2004 Vol.17(Supplement)
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2004, 18(Supplement).
Abstract:
Nowadays the research and development of CNG engine is coming into a hotspot in engine industry of China. Because of the specific character of turbo-charged CNG engine, the ignition needs more energy than petrol engine. The hardware and software of electronic controlled high-energy direct ignition system (ECHDIS) based on microprocessor used in turbo-charged natural gas engine are described, the simulation results of the ignition circuit in the design of system which is used to instruct the design of the system are also given out. The experiment results show that the system reach the requirement, the result of ignition energy is according to the simulation result.
Nowadays the research and development of CNG engine is coming into a hotspot in engine industry of China. Because of the specific character of turbo-charged CNG engine, the ignition needs more energy than petrol engine. The hardware and software of electronic controlled high-energy direct ignition system (ECHDIS) based on microprocessor used in turbo-charged natural gas engine are described, the simulation results of the ignition circuit in the design of system which is used to instruct the design of the system are also given out. The experiment results show that the system reach the requirement, the result of ignition energy is according to the simulation result.
2004, 18(Supplement).
Abstract:
Testing the dynamic response characteristics of the whole transmission system with roller gear cam indexing mechanisms by changing its some parameters has been made. The experiments mainly test changing circumstances of tangential acceleration at arbitrary point of the pitch circle on the loaded plate to simulate working of load and decided dynamic characteristics of the system. According to the results of the experiments, the conclusions that the indexing case has many different resonance frequencies in actual working condition and the backlash between roller gear and cam has relationship with the indexing quality of roller gear cam indexing mechanism have been drawn.
Testing the dynamic response characteristics of the whole transmission system with roller gear cam indexing mechanisms by changing its some parameters has been made. The experiments mainly test changing circumstances of tangential acceleration at arbitrary point of the pitch circle on the loaded plate to simulate working of load and decided dynamic characteristics of the system. According to the results of the experiments, the conclusions that the indexing case has many different resonance frequencies in actual working condition and the backlash between roller gear and cam has relationship with the indexing quality of roller gear cam indexing mechanism have been drawn.
2004, 18(Supplement).
Abstract:
Aimed at sensitivity to profile and position error, selecting crank-leader mechanism as example, through constraint analysis, discover that planar closed chain mechanism is subjected to ideal plane, in fact, in which there normally is redundant constraint. This kind of redundant constraint resulted that the system is very sensitive to manufacture error, and require very high manufacture precision. Therefore, configure constraint and freedom rightly, and design self-adjustability mechanism, all these methods will decrease sensitivity resulted from error, reduce manufacture cost and assembly difficulty, promote transmission efficiency, and prolong using life. In this way, oriented from structure factors, it eliminate effect on machine quality resulted from error, which include manufacture, assembly and working condition, so whole mechanism's robustness has improved obviously.
Aimed at sensitivity to profile and position error, selecting crank-leader mechanism as example, through constraint analysis, discover that planar closed chain mechanism is subjected to ideal plane, in fact, in which there normally is redundant constraint. This kind of redundant constraint resulted that the system is very sensitive to manufacture error, and require very high manufacture precision. Therefore, configure constraint and freedom rightly, and design self-adjustability mechanism, all these methods will decrease sensitivity resulted from error, reduce manufacture cost and assembly difficulty, promote transmission efficiency, and prolong using life. In this way, oriented from structure factors, it eliminate effect on machine quality resulted from error, which include manufacture, assembly and working condition, so whole mechanism's robustness has improved obviously.
2004, 18(Supplement).
Abstract:
Firstly, based on the Jacobian matrixes relating the input speeds with the output speeds of mechanisms, a general method, which is used for solving the singularities of planar multi-loop multi-DOF mechanisms with sliding pairs, is presented. Secondly, four kinds of singularities of the hybrid mechanisms used in the metal forming presses are analyzed in detail by this method. Its five kinds of singular positions whose characteristics are discussed respectively are discovered. And three methods are proposed on how to avoid the singular positions of planar multi-loop multi-DOF mechanisms with sliding pairs. Based on the assemblability of planar single-loop N-bar kinematic chains or linkages, the geometry conditions are investigated and discovered to avoid the singular positions of the hybrid mechanisms. In order to verify aforementioned conclusions, a case is given in which the singular curves are plotted and simulated.
Firstly, based on the Jacobian matrixes relating the input speeds with the output speeds of mechanisms, a general method, which is used for solving the singularities of planar multi-loop multi-DOF mechanisms with sliding pairs, is presented. Secondly, four kinds of singularities of the hybrid mechanisms used in the metal forming presses are analyzed in detail by this method. Its five kinds of singular positions whose characteristics are discussed respectively are discovered. And three methods are proposed on how to avoid the singular positions of planar multi-loop multi-DOF mechanisms with sliding pairs. Based on the assemblability of planar single-loop N-bar kinematic chains or linkages, the geometry conditions are investigated and discovered to avoid the singular positions of the hybrid mechanisms. In order to verify aforementioned conclusions, a case is given in which the singular curves are plotted and simulated.
2004, 18(Supplement).
Abstract:
A vibration absorber for the suspending beam subjected to the impulse excitation has been developed following the suppose, which is for solving the problems of vibration existed in the systems like the robotics and gun. The isolation and absorption theory for the vibration of the rigid bodies and the elastic beams have been employed and developed to analyze the absorber after simplifying the excitations exerted on the beam, the vibration absorption principles are expressed in terms of waves of propagating so that the design of absorber can be proceeded by analysis of the transmission and reflection coefficients matrices. The form and structure of the absorber, the design method based on the experiments, and the nonlinearity of the absorber have also been discussed. The test and experiment of the isolation vibration show the effectiveness of the new equipment. The vibration absorber is a solution to the vibration at the end of the beam subjected to the impulse excitation.
A vibration absorber for the suspending beam subjected to the impulse excitation has been developed following the suppose, which is for solving the problems of vibration existed in the systems like the robotics and gun. The isolation and absorption theory for the vibration of the rigid bodies and the elastic beams have been employed and developed to analyze the absorber after simplifying the excitations exerted on the beam, the vibration absorption principles are expressed in terms of waves of propagating so that the design of absorber can be proceeded by analysis of the transmission and reflection coefficients matrices. The form and structure of the absorber, the design method based on the experiments, and the nonlinearity of the absorber have also been discussed. The test and experiment of the isolation vibration show the effectiveness of the new equipment. The vibration absorber is a solution to the vibration at the end of the beam subjected to the impulse excitation.
2004, 18(Supplement).
Abstract:
In the past years parallel machine tools (PMTs) have drawn more and more interest for the advantages of high rigidity, low cost, high accuracy, high velocity and high acceleration. Parallel machine tool prototype design includes conceptual design, kinematic detail design, dynamic design, etc. The conceptual design is an iterative, complex, decision-making and creative process. Conceptual design mostly focuses on parallel manipulators enumeration in current research. The purpose of this paper is to provide a computer-aided conceptual design approach for parallel machine tool design. Firstly the design procedure and system architecture framework of parallel machine tool is proposed. Then a virtual conceptual design method is put forward which includes three steps: ①Design requirement specification. ②Motion dispatching. ③Parallel mechanism and other mechanism configuration design. ④3D modeling and simulation. The conceptual design software park for PMT is developed by UG development with Visual C++. The whole virtual conceptual design process and essential technique are illustrated by examples.
In the past years parallel machine tools (PMTs) have drawn more and more interest for the advantages of high rigidity, low cost, high accuracy, high velocity and high acceleration. Parallel machine tool prototype design includes conceptual design, kinematic detail design, dynamic design, etc. The conceptual design is an iterative, complex, decision-making and creative process. Conceptual design mostly focuses on parallel manipulators enumeration in current research. The purpose of this paper is to provide a computer-aided conceptual design approach for parallel machine tool design. Firstly the design procedure and system architecture framework of parallel machine tool is proposed. Then a virtual conceptual design method is put forward which includes three steps: ①Design requirement specification. ②Motion dispatching. ③Parallel mechanism and other mechanism configuration design. ④3D modeling and simulation. The conceptual design software park for PMT is developed by UG development with Visual C++. The whole virtual conceptual design process and essential technique are illustrated by examples.
2004, 18(Supplement).
Abstract:
To obtain more DOFs by fewer actuators with lower control difficulty, under-actuated mechanical fingers are needed, so that a robot hand can grasp objects much better and is more similar to human hand. The design idea on under-actuated fingers is enlarged, and an experimental under-actuated finger mechanism is developed. As a finger of a robot hand or a part of a finger, this mechanism makes a robot hand has fewer drivers, but more DOFs. It can realize passive adaptive grasping objects of different shapes and sizes without any extra requirements of control precision. With the properties of small, light, but reliable, it is easy to produce. The main parameters for design are also described in detail.
To obtain more DOFs by fewer actuators with lower control difficulty, under-actuated mechanical fingers are needed, so that a robot hand can grasp objects much better and is more similar to human hand. The design idea on under-actuated fingers is enlarged, and an experimental under-actuated finger mechanism is developed. As a finger of a robot hand or a part of a finger, this mechanism makes a robot hand has fewer drivers, but more DOFs. It can realize passive adaptive grasping objects of different shapes and sizes without any extra requirements of control precision. With the properties of small, light, but reliable, it is easy to produce. The main parameters for design are also described in detail.
2004, 18(Supplement).
Abstract:
A novel 5-axis parallel machine tool family is presented. The basic idea behind this family is to use an additional passive constraint limb to restrict the rotational DOF(Degrees of freedom) of the moving platform, which is an unnecessary DOF in the 5-axis machining process. The structures of the constraint limb are synthesized by screw theory. By adding sensors on the joints of the constraint limb, the configuration of the moving platform is available by reverse kinematics so that closed-loop control for the machine tool can be implemented.
A novel 5-axis parallel machine tool family is presented. The basic idea behind this family is to use an additional passive constraint limb to restrict the rotational DOF(Degrees of freedom) of the moving platform, which is an unnecessary DOF in the 5-axis machining process. The structures of the constraint limb are synthesized by screw theory. By adding sensors on the joints of the constraint limb, the configuration of the moving platform is available by reverse kinematics so that closed-loop control for the machine tool can be implemented.
2004, 18(Supplement).
Abstract:
A novel mechanical press for precision drawing is presented, which is composed of a nine-bar linkage driven by hybrid mechanism. The motion of this linkage is studied by kinematics analysis firstly. The optimization method and model are developed. The actual displacement curves of slider can approach to the ideal ones by two step's optimization. The dimension of the linkage and the motion rules of servomotor have been optimized. Therefore, by rightly designing the input motion of servomotor, the slider can pass through a group of more desired trajectory suitable for precision drawing.
A novel mechanical press for precision drawing is presented, which is composed of a nine-bar linkage driven by hybrid mechanism. The motion of this linkage is studied by kinematics analysis firstly. The optimization method and model are developed. The actual displacement curves of slider can approach to the ideal ones by two step's optimization. The dimension of the linkage and the motion rules of servomotor have been optimized. Therefore, by rightly designing the input motion of servomotor, the slider can pass through a group of more desired trajectory suitable for precision drawing.
2004, 18(Supplement).
Abstract:
The characteristics of surface generation of roller gear cam are studied by applying meshing theory of conjugate surfaces. Transformation matrixes between indexing cam and rollers in turret are defined first. Then the enveloping condition between cam and rollers in turret is derived by enveloping theory. Based on above work, cam surface equations are built. According to the enveloping properties of this kind of mechanism, solid model of cam is obtained through Boolean operation. The application software is developed in the environment of solid edge and an example of a roller gear indexing cam used in engineering practice is given. The solid model generating using this method reflects the geometry characteristic and can be used in analysis of cam profile. This method can also be expanded to solid modeling of more complicated cam surface.
The characteristics of surface generation of roller gear cam are studied by applying meshing theory of conjugate surfaces. Transformation matrixes between indexing cam and rollers in turret are defined first. Then the enveloping condition between cam and rollers in turret is derived by enveloping theory. Based on above work, cam surface equations are built. According to the enveloping properties of this kind of mechanism, solid model of cam is obtained through Boolean operation. The application software is developed in the environment of solid edge and an example of a roller gear indexing cam used in engineering practice is given. The solid model generating using this method reflects the geometry characteristic and can be used in analysis of cam profile. This method can also be expanded to solid modeling of more complicated cam surface.
2004, 18(Supplement).
Abstract:
The method to design a compact hand for humanoid robots is explored. The developed humanoid hand has human-like 5 fingers and 14 joints, driven through cable by two motors. The ratios of cable gear are decided based on human's hand configuration for manipulating fundamental tasks such as grasping cups, holding books, shaking hands and making gesture. The size of the developed humanoid hand is similar to the human's, and its mass is 0.39 kg. The effectiveness of our developed humanoid hand was confirmed by experiments.
The method to design a compact hand for humanoid robots is explored. The developed humanoid hand has human-like 5 fingers and 14 joints, driven through cable by two motors. The ratios of cable gear are decided based on human's hand configuration for manipulating fundamental tasks such as grasping cups, holding books, shaking hands and making gesture. The size of the developed humanoid hand is similar to the human's, and its mass is 0.39 kg. The effectiveness of our developed humanoid hand was confirmed by experiments.
2004, 18(Supplement).
Abstract:
Tribology properties of the friction pair composed of silicon nitride Si3N4 ceramic and chilled cast iron, which will possibly be used as antiwear materials for automotive engines, are studied. In the experimental design, the method called uniform distribution is adopted to choose the reasonable values of parameters, and wear rates, wear mechanism under unlubricated condition are measured and analyzed. In addition, friction coefficients in different lubricant states are also obtained and compared. The experimental results reveal that fatigue wear is dominant to Si3N4 ceramic, but adhesive wear is obvious to chilled cast iron; the friction coefficients between Si3N4 ceramic and chilled cast iron under unlubricated condition are much bigger than lubricated condition.
Tribology properties of the friction pair composed of silicon nitride Si3N4 ceramic and chilled cast iron, which will possibly be used as antiwear materials for automotive engines, are studied. In the experimental design, the method called uniform distribution is adopted to choose the reasonable values of parameters, and wear rates, wear mechanism under unlubricated condition are measured and analyzed. In addition, friction coefficients in different lubricant states are also obtained and compared. The experimental results reveal that fatigue wear is dominant to Si3N4 ceramic, but adhesive wear is obvious to chilled cast iron; the friction coefficients between Si3N4 ceramic and chilled cast iron under unlubricated condition are much bigger than lubricated condition.
2004, 18(Supplement).
Abstract:
A comprehensive dynamic analysis is performed for the impulse variable speed device. On the one hand, the system is simplified an equivalent dynamic model considering the friction in pairs and the speed of electromotor. On the other hand, the dynamic model of wedge process is constructed for the roller clutch involving the elastic contact and the rolling friction. Finally, the kineto-elastodynamic (KED) analysis is carried out for this mechanism in consideration of all the factors mentioned above. Then the characteristic kinematic and dynamic, the constrained forces in pairs and the dynamic proc-ess of the roller clutch are educed considering the vibration. A basis for the development and dynamic design of the variable speed device are provided.
A comprehensive dynamic analysis is performed for the impulse variable speed device. On the one hand, the system is simplified an equivalent dynamic model considering the friction in pairs and the speed of electromotor. On the other hand, the dynamic model of wedge process is constructed for the roller clutch involving the elastic contact and the rolling friction. Finally, the kineto-elastodynamic (KED) analysis is carried out for this mechanism in consideration of all the factors mentioned above. Then the characteristic kinematic and dynamic, the constrained forces in pairs and the dynamic proc-ess of the roller clutch are educed considering the vibration. A basis for the development and dynamic design of the variable speed device are provided.
2004, 18(Supplement).
Abstract:
The kinematics of 1-DOF planar parallel unsymmetrical mechanisms—RSSR-SC has been studied with kinematical influence coefficient method. Some novel kinematical performance indices for parallel mechanism including velocity and acceleration indices are presented based on the kinematics influence coefficient matrices. According to these performance indices, the kinematical performance of mechanisms—RSSR-SC is studied and the relationship between the design parameters and its kinematical performance are given by performance atlases which would be helpful for mechanism design.
The kinematics of 1-DOF planar parallel unsymmetrical mechanisms—RSSR-SC has been studied with kinematical influence coefficient method. Some novel kinematical performance indices for parallel mechanism including velocity and acceleration indices are presented based on the kinematics influence coefficient matrices. According to these performance indices, the kinematical performance of mechanisms—RSSR-SC is studied and the relationship between the design parameters and its kinematical performance are given by performance atlases which would be helpful for mechanism design.
2004, 18(Supplement).
Abstract:
A new physical meaning of manipulability measure is given. Reduced manipulability is analyzed, and arm length index and rotation angle index which express fault tolerant workspace and actual manipulability respectively are proposed. Synchronous fault tolerant planning of joint motion and end-effector motion is researched by simulation examples for a planar 3R manipulator. Research results show that the maximization of rotation angle index can avoid the singular configuration of the reduced manipulator at a failure moment, while the maximization of arm length index can avoid the singular configuration of the reduced manipulator after a failure.
A new physical meaning of manipulability measure is given. Reduced manipulability is analyzed, and arm length index and rotation angle index which express fault tolerant workspace and actual manipulability respectively are proposed. Synchronous fault tolerant planning of joint motion and end-effector motion is researched by simulation examples for a planar 3R manipulator. Research results show that the maximization of rotation angle index can avoid the singular configuration of the reduced manipulator at a failure moment, while the maximization of arm length index can avoid the singular configuration of the reduced manipulator after a failure.
2004, 18(Supplement).
Abstract:
The maintenance of high voltage power line is very difficult job and the usage of robot is a good solution. The dynamic character of robot and its supporting mechanism in operation of maintenance of high voltage power line is analyzed. Object tracking scheme based on visual servoing is presented to track the object, which is in relative motion. Trajectory prediction of moving object is formed by differential features of intrinsic geometry. Window technique is used to improve the efficiency of feature searching and processing. Experiments of replacing old insulators on 4 kV voltage power line were conducted and the control methods were verified.
The maintenance of high voltage power line is very difficult job and the usage of robot is a good solution. The dynamic character of robot and its supporting mechanism in operation of maintenance of high voltage power line is analyzed. Object tracking scheme based on visual servoing is presented to track the object, which is in relative motion. Trajectory prediction of moving object is formed by differential features of intrinsic geometry. Window technique is used to improve the efficiency of feature searching and processing. Experiments of replacing old insulators on 4 kV voltage power line were conducted and the control methods were verified.
2004, 18(Supplement).
Abstract:
A novel approach for modeling the manipulator kinematics and solving the feasible motions of a manipulator is presented. The precise path tracking of the end effector through singular configurations is achieved. The linear dependence of the columns and the corresponding rows of the Jacobian matrix at a singular configuration is found by using the null-space approach. As a result, the feasible motions in Cartesian space can be determined. A unique mapping between the feasible motion in Cartesian space and the joint space motion ensures precise path tracking of a manipulator through singular configurations.
A novel approach for modeling the manipulator kinematics and solving the feasible motions of a manipulator is presented. The precise path tracking of the end effector through singular configurations is achieved. The linear dependence of the columns and the corresponding rows of the Jacobian matrix at a singular configuration is found by using the null-space approach. As a result, the feasible motions in Cartesian space can be determined. A unique mapping between the feasible motion in Cartesian space and the joint space motion ensures precise path tracking of a manipulator through singular configurations.
2004, 18(Supplement).
Abstract:
An overview of innovative design of the indexing cam mechanisms is presented. The improvement of the existing mechanism and some inventions are introduced. The properties of traditional types of indexing cam mechanisms and their improvements are discussed. Some new types of indexing cam mechanisms are given to point out the trends of development in such mechanisms. The creative design of the planetary indexing cam mechanism is highlighted, and a prototype of this new mechanism is introduced.
An overview of innovative design of the indexing cam mechanisms is presented. The improvement of the existing mechanism and some inventions are introduced. The properties of traditional types of indexing cam mechanisms and their improvements are discussed. Some new types of indexing cam mechanisms are given to point out the trends of development in such mechanisms. The creative design of the planetary indexing cam mechanism is highlighted, and a prototype of this new mechanism is introduced.
2004, 18(Supplement).
Abstract:
A parametric model for the dynamics of an adjustable linear oil damper equipped in advanced rail vehicles is developed. Instantaneous flow loss, oil compressibility, oil temperature and valve dynamics, etc. are taken into account in the nonlinear modeling process. A computer package based on the model is developed in MATLAB environment and numerical analyses are carried out on the damping performance by help of parameters identification. Experiments with a CAT rig are done at last and satisfied agreement is achieved between the numerical prediction and experiments. Oil temperature effect on the damping force rating is also investigated.
A parametric model for the dynamics of an adjustable linear oil damper equipped in advanced rail vehicles is developed. Instantaneous flow loss, oil compressibility, oil temperature and valve dynamics, etc. are taken into account in the nonlinear modeling process. A computer package based on the model is developed in MATLAB environment and numerical analyses are carried out on the damping performance by help of parameters identification. Experiments with a CAT rig are done at last and satisfied agreement is achieved between the numerical prediction and experiments. Oil temperature effect on the damping force rating is also investigated.
2004, 18(Supplement).
Abstract:
The dynamic response of the vibration of a lunar lander to the impact of the moon surface with damping has been investigated. Based on the general analysis for landing process of the lunar lander, the dynamic model of the linear damping free vibration with multi-degrees of freedom is set up by means of the way of collision between elastic bodies. A formula concerning the vibration of the lunar lander has been obtained from a theoretical analysis. The vibration equations of the lunar lander is analyzed from the Lagrange equations. Basing on the ADAMS mechanical simulation software, a microgravity environment has been established in computer. The result has been verified by a numerical example, and the simulation result is in very good agreement with the calculated one. The conclusions obtained can be used for design and analysis of the vibrations of the lunar lander.
The dynamic response of the vibration of a lunar lander to the impact of the moon surface with damping has been investigated. Based on the general analysis for landing process of the lunar lander, the dynamic model of the linear damping free vibration with multi-degrees of freedom is set up by means of the way of collision between elastic bodies. A formula concerning the vibration of the lunar lander has been obtained from a theoretical analysis. The vibration equations of the lunar lander is analyzed from the Lagrange equations. Basing on the ADAMS mechanical simulation software, a microgravity environment has been established in computer. The result has been verified by a numerical example, and the simulation result is in very good agreement with the calculated one. The conclusions obtained can be used for design and analysis of the vibrations of the lunar lander.
2004, 18(Supplement).
Abstract:
The spatial compliance behavior of the robots with elastic joints and links via screw theory is studied. After a brief discussion on the screw theory of robots with elastic joints, the Von Mises' beam theory is introduced to represent for the spatial compliance of the link, and the compliance behavior of the manipulator with elastic links is analyzed. Then, the kinematics of the robots with elastic links and joints is further discussed. And the connection between the compliance of the whole manipulator system and its individual joints and links is obtained. It is convinced by our study that the screw theory is a facilitated mathematical tool for the representation and analysis of robotic system with spatial compliance.
The spatial compliance behavior of the robots with elastic joints and links via screw theory is studied. After a brief discussion on the screw theory of robots with elastic joints, the Von Mises' beam theory is introduced to represent for the spatial compliance of the link, and the compliance behavior of the manipulator with elastic links is analyzed. Then, the kinematics of the robots with elastic links and joints is further discussed. And the connection between the compliance of the whole manipulator system and its individual joints and links is obtained. It is convinced by our study that the screw theory is a facilitated mathematical tool for the representation and analysis of robotic system with spatial compliance.
2004, 18(Supplement).
Abstract:
In order to deal with the troublesome situation in analyzing the complicated mechanism precision, a modular differentiation method for mechanism precision analysis is put forward to simplify the work, and the method is very suitable to the computation through computer. Also general error influence coefficient equations are deduced for several common use basic mechanisms, and a analytical example is shown.
In order to deal with the troublesome situation in analyzing the complicated mechanism precision, a modular differentiation method for mechanism precision analysis is put forward to simplify the work, and the method is very suitable to the computation through computer. Also general error influence coefficient equations are deduced for several common use basic mechanisms, and a analytical example is shown.
2004, 18(Supplement).
Abstract:
A beam element model with 2 nodes and 10 degrees of freedom for elastic linkage mechanism with alloy damped sandwich structure is put forward. Both shear and axial deformations in damping layer of the beam are taken into account in the model. The damping is considered according to complex damping model, and the element mass matrix, complex stiffness matrix as well as element differential equations of motion are deduced. Furthermore, element models are assembled into a system model, which is a differential equation with variable coefficient matrixes, and the corresponding numerical method for the model is developed. Agreements between numerical analysis and experimental results are quite well. It is fully shown that the theoretical model and the numerical method addressed in the paper are correct and feasible.
A beam element model with 2 nodes and 10 degrees of freedom for elastic linkage mechanism with alloy damped sandwich structure is put forward. Both shear and axial deformations in damping layer of the beam are taken into account in the model. The damping is considered according to complex damping model, and the element mass matrix, complex stiffness matrix as well as element differential equations of motion are deduced. Furthermore, element models are assembled into a system model, which is a differential equation with variable coefficient matrixes, and the corresponding numerical method for the model is developed. Agreements between numerical analysis and experimental results are quite well. It is fully shown that the theoretical model and the numerical method addressed in the paper are correct and feasible.
2004, 18(Supplement).
Abstract:
A robust synthesis model considering structural and mechanical errors for the elastic linkages is constructed and its synthesis procedure is presented. This model overcomes disadvantages of the previous works that usually dealt with these two kinds of errors separately, not incorporated. A 4-bar path generating linkage is selected for numerical illustration. The comparison of the results from the robust synthesis procedure with those from the traditional deterministic synthesis indicates that the former has a more accurate results than the latter.
A robust synthesis model considering structural and mechanical errors for the elastic linkages is constructed and its synthesis procedure is presented. This model overcomes disadvantages of the previous works that usually dealt with these two kinds of errors separately, not incorporated. A 4-bar path generating linkage is selected for numerical illustration. The comparison of the results from the robust synthesis procedure with those from the traditional deterministic synthesis indicates that the former has a more accurate results than the latter.
2004, 18(Supplement).
Abstract:
Use Cnv group decomposes distributed polynomial into the orthogonal functions in periodic region, and the periodic function is approached by those orthogonal functions. The structure of beam is expanded to periodic region and additional forces is added to the beam to make the displacement of beam to be periodic function, and therefore the displacement can be approached by those orthogonal function. Efficiency of the partial defined function are gotten by the Rice method, and the additional forces are determined by boundary condition. This method is elementally to be finite element method. Because of using the orthogonal function the calculation is greatly reduced the calculation is similar to method of boundary element.
Use Cnv group decomposes distributed polynomial into the orthogonal functions in periodic region, and the periodic function is approached by those orthogonal functions. The structure of beam is expanded to periodic region and additional forces is added to the beam to make the displacement of beam to be periodic function, and therefore the displacement can be approached by those orthogonal function. Efficiency of the partial defined function are gotten by the Rice method, and the additional forces are determined by boundary condition. This method is elementally to be finite element method. Because of using the orthogonal function the calculation is greatly reduced the calculation is similar to method of boundary element.
2004, 18(Supplement).
Abstract:
A computerized method is presented to calculate the spatial cam surfaces without their analytic expressions. Given the definitions of the follower surface and the assembly configuration as well as the motions, a computerized model and algorithm are developed to compute the cam surfaces through transformation of the enveloping condition. This new idea makes it possible to construct a truly versatile CAD/CAM program for whatever type cam mechanisms. This new method is illustrated with an example.
A computerized method is presented to calculate the spatial cam surfaces without their analytic expressions. Given the definitions of the follower surface and the assembly configuration as well as the motions, a computerized model and algorithm are developed to compute the cam surfaces through transformation of the enveloping condition. This new idea makes it possible to construct a truly versatile CAD/CAM program for whatever type cam mechanisms. This new method is illustrated with an example.
2004, 18(Supplement).
Abstract:
The analysis and simulation of the dynamical behaviour of a novel two-wheeled mobile robot are reported. Its novelty is lying in the ease with which it can be controlled, as a result of its qua-siholonomy, a concept introduced elsewhere. The mathematical model of the robot is formulated in the framework of the Lagrange formalism, by means of an orthogonal complement and the holonomy matrix, concepts introduced in previous works. A few simulations for the validation of the aforemen-tioned model have been conducted. Moreover, the dynamic response to different inputs and different initial conditions are provided, which is crucial for the design and control of the robot.
The analysis and simulation of the dynamical behaviour of a novel two-wheeled mobile robot are reported. Its novelty is lying in the ease with which it can be controlled, as a result of its qua-siholonomy, a concept introduced elsewhere. The mathematical model of the robot is formulated in the framework of the Lagrange formalism, by means of an orthogonal complement and the holonomy matrix, concepts introduced in previous works. A few simulations for the validation of the aforemen-tioned model have been conducted. Moreover, the dynamic response to different inputs and different initial conditions are provided, which is crucial for the design and control of the robot.
2004, 18(Supplement).
Abstract:
The point of view that the uncertainty of planar constraint causes overconstraint to exert a series of harmful influences on mechanisms because of inevitable errors and other factors is presented. An analysis method is introduced to determine the number and characteristics of overconstraint. Some principles for the arrangement of kinematic pairs are also proposed. The test of mechanical efficiency verified the methods for reducing and eliminating harmful influences come from overconstraint.
The point of view that the uncertainty of planar constraint causes overconstraint to exert a series of harmful influences on mechanisms because of inevitable errors and other factors is presented. An analysis method is introduced to determine the number and characteristics of overconstraint. Some principles for the arrangement of kinematic pairs are also proposed. The test of mechanical efficiency verified the methods for reducing and eliminating harmful influences come from overconstraint.
2004, 18(Supplement).
Abstract:
A case-based similar design method is proposed for design concept generation of mechanical products. At first design requirement model and concept case model are established. Design requirement model is a tree-like data structure with three branches: usage branch, function branch and design restrict branch whose leaves denoting design requirement items. Concept case model is a tree-like data structure with four branches: usage branch, function branch, character branch and structure branch. Concept cases are put into a concept case base. Conceptual design compares design requirement with each concept case in the concept case base. Comparing result is measured by simi-lar degree. Finally concept case is selected according to concept cases sorting result by similar degree. The key problems are discussed such as similar item generation, similar degree calculation, etc.
A case-based similar design method is proposed for design concept generation of mechanical products. At first design requirement model and concept case model are established. Design requirement model is a tree-like data structure with three branches: usage branch, function branch and design restrict branch whose leaves denoting design requirement items. Concept case model is a tree-like data structure with four branches: usage branch, function branch, character branch and structure branch. Concept cases are put into a concept case base. Conceptual design compares design requirement with each concept case in the concept case base. Comparing result is measured by simi-lar degree. Finally concept case is selected according to concept cases sorting result by similar degree. The key problems are discussed such as similar item generation, similar degree calculation, etc.
2004, 18(Supplement).
Abstract:
A systematic method to design dimension of every component and load balance mechanism for satellite gear trains(SGTs) is provided. Based on investigation of the transmitting characteristics of the trains, the calculating formulae are deduced for the torque of every component of SGTs. The structural characteristics of load balance for SGTs is analyzed, some design schemes are presented for load balance system of SGTs. A new calculating method is presented for equivalent error capacity of the load balance mechanism by considering probability characteristics of the system which are originated by manufacturing errors and assembling deformation of SGTs.
A systematic method to design dimension of every component and load balance mechanism for satellite gear trains(SGTs) is provided. Based on investigation of the transmitting characteristics of the trains, the calculating formulae are deduced for the torque of every component of SGTs. The structural characteristics of load balance for SGTs is analyzed, some design schemes are presented for load balance system of SGTs. A new calculating method is presented for equivalent error capacity of the load balance mechanism by considering probability characteristics of the system which are originated by manufacturing errors and assembling deformation of SGTs.
2004, 18(Supplement).
Abstract:
A new method is proposed, by which the installation stiffness of machines can be identified on the base of experimental modal data, eigenfrequencies and eigenmodes for changed mounting stiffness can be predicted. The present method is successfully applied on a printing unit of a sheet-fed printing machine, which is investigated experimentally and theoretically. The identified stiffness points out, that the printing unit is unevenly installed, and this fact has been verified through thefollowed measurement. According to the simulation results, the uneven installation has an obvious influence on the printing quality.
A new method is proposed, by which the installation stiffness of machines can be identified on the base of experimental modal data, eigenfrequencies and eigenmodes for changed mounting stiffness can be predicted. The present method is successfully applied on a printing unit of a sheet-fed printing machine, which is investigated experimentally and theoretically. The identified stiffness points out, that the printing unit is unevenly installed, and this fact has been verified through thefollowed measurement. According to the simulation results, the uneven installation has an obvious influence on the printing quality.
2004, 18(Supplement).
Abstract:
Shape selection and dimension design of direct jet spray nozzle are done. Relationship between system pressure p, nozzle inner structure dimension and outer atomization characteristics are analyzed. Simulation results show that the nozzle outlet diameter and system pressure are the crucial two factors for spray atomization. When system flow rate qv is 16 Ml/r and system pressure p is 14 Mpa, the optimal outlet diameter is about 1.5 mm, Trifle fluctuation of outlet diameter may cause great affection to water droplets' sauter mean diameter (SMD)D32, and 8~9 Mpa is the baseline of stable atomization pressure. Simulation results are experimentally verified. Besides, nozzle cylinder length l/d = 2 and pinch angle a = 30˚~60˚ is the best structure to this type of nozzle, jet distance is about 9 m in this condition.
Shape selection and dimension design of direct jet spray nozzle are done. Relationship between system pressure p, nozzle inner structure dimension and outer atomization characteristics are analyzed. Simulation results show that the nozzle outlet diameter and system pressure are the crucial two factors for spray atomization. When system flow rate qv is 16 Ml/r and system pressure p is 14 Mpa, the optimal outlet diameter is about 1.5 mm, Trifle fluctuation of outlet diameter may cause great affection to water droplets' sauter mean diameter (SMD)D32, and 8~9 Mpa is the baseline of stable atomization pressure. Simulation results are experimentally verified. Besides, nozzle cylinder length l/d = 2 and pinch angle a = 30˚~60˚ is the best structure to this type of nozzle, jet distance is about 9 m in this condition.
2004, 18(Supplement).
Abstract:
A three-ring planetary gear transmission is a novel type of planetary transmission with small tooth number difference. Compared with traditional planetary and gear transmissions, it has many distinguished advantages such as large speed-reduction ratio, high load capability, compact volume etc. One main problem of this transmission is, however, the pre-mature fatigue of bearings. Based on dynamic simulation, this paper analyzes the dynamic load of the planetary bearings and housing bearings in both input shaft and support shaft. The analysis result indicates that the planetary bearings in input shaft are in the most severe condition of load. This is almost coincided with the fatigue records of bearings reported in past publications. A guideline for design of the transmission can be drawn .
A three-ring planetary gear transmission is a novel type of planetary transmission with small tooth number difference. Compared with traditional planetary and gear transmissions, it has many distinguished advantages such as large speed-reduction ratio, high load capability, compact volume etc. One main problem of this transmission is, however, the pre-mature fatigue of bearings. Based on dynamic simulation, this paper analyzes the dynamic load of the planetary bearings and housing bearings in both input shaft and support shaft. The analysis result indicates that the planetary bearings in input shaft are in the most severe condition of load. This is almost coincided with the fatigue records of bearings reported in past publications. A guideline for design of the transmission can be drawn .
2004, 18(Supplement).
Abstract:
Six parallel cables drive the feed cabin of a large radio telescope to track a radio source with a span of 500 m. Having a large span and a configuration of parallel robot, the cabin-cable system can be considered as a huge parallel cable robot. A scheme for calibration of the initial cable lengths is presented based on the relationship between the cable lengths and tensions. The calibration is implemented indirectly by tuning the initial moments of the six servomotors. The experiment of 50 m scaled model verifies the necessity and validity of the calibration.
Six parallel cables drive the feed cabin of a large radio telescope to track a radio source with a span of 500 m. Having a large span and a configuration of parallel robot, the cabin-cable system can be considered as a huge parallel cable robot. A scheme for calibration of the initial cable lengths is presented based on the relationship between the cable lengths and tensions. The calibration is implemented indirectly by tuning the initial moments of the six servomotors. The experiment of 50 m scaled model verifies the necessity and validity of the calibration.
2004, 18(Supplement).
Abstract:
Ohio State (OSU) and Stanford Universities are cooperating to understand quadruped galloping through the design of a self-contained, biomimetic, galloping robot. The leg for this quadruped was first designed at Ohio State University (OSU). A second-generation leg, with the same functional geometry, has been designed and tested at Stanford University. The objective of these tests was to determine that the single leg would be capable of prolonged operation at a velocity of 5m/s, and that the control system, developed in simulation, would function under real-world conditions. The mechanical design of the quadruped is based on properties of biological quadruped animal legs. Important biomimetic design characteristics include minimal impact loss, elastic energy storage, and low inertia. The cable linkage, which works against a large spring to flex the knee, is uncoupled from the front-to-back hip actuator through a parallelogram-like cable mechanism. The controller developed for the leg is a direct adaptive fuzzy controller. The direct adaptive approach does not require system identification and can use heuristics to successfully control a complex system. With this controller, a single 2DOF leg constrained in yaw, pitch, roll and transverse translation can be successfully controlled. This controller was executed once each cycle at the top-of-flight. Parameters set by the controller were passed to PD controllers at each of the 2 joints: the hip and cable-actuated knee. The control of this leg required only 7×5×3 = 105 rules, each with a corresponding output for thigh and knee angle. This controller was implemented on an embedded processor attached to the leg. The leg reached a speed of 3 m/s. Modifications to the leg will increase this speed. The controller successfully adapted to the leg.
Ohio State (OSU) and Stanford Universities are cooperating to understand quadruped galloping through the design of a self-contained, biomimetic, galloping robot. The leg for this quadruped was first designed at Ohio State University (OSU). A second-generation leg, with the same functional geometry, has been designed and tested at Stanford University. The objective of these tests was to determine that the single leg would be capable of prolonged operation at a velocity of 5m/s, and that the control system, developed in simulation, would function under real-world conditions. The mechanical design of the quadruped is based on properties of biological quadruped animal legs. Important biomimetic design characteristics include minimal impact loss, elastic energy storage, and low inertia. The cable linkage, which works against a large spring to flex the knee, is uncoupled from the front-to-back hip actuator through a parallelogram-like cable mechanism. The controller developed for the leg is a direct adaptive fuzzy controller. The direct adaptive approach does not require system identification and can use heuristics to successfully control a complex system. With this controller, a single 2DOF leg constrained in yaw, pitch, roll and transverse translation can be successfully controlled. This controller was executed once each cycle at the top-of-flight. Parameters set by the controller were passed to PD controllers at each of the 2 joints: the hip and cable-actuated knee. The control of this leg required only 7×5×3 = 105 rules, each with a corresponding output for thigh and knee angle. This controller was implemented on an embedded processor attached to the leg. The leg reached a speed of 3 m/s. Modifications to the leg will increase this speed. The controller successfully adapted to the leg.
2004, 18(Supplement).
Abstract:
The involute gearing with small tooth number is usually referred to gearing transmission including a pinion with few teeth. Such problems as continuous transmission, avoiding undercutting and pointing of the pinion must be solved in the design. On the base of analyzing gearing with small tooth number, design points of the gearing with small tooth number are studied. Different minimum helix angle and corresponding modification coefficient of the pinion when the number of tooth of pinion is different. From the angle of practical using, the recommended practical number of teeth, helix angle and range of the modification coefficient of the pinion are given, which will provide scientific basis for selecting basic parameters appropriately.
The involute gearing with small tooth number is usually referred to gearing transmission including a pinion with few teeth. Such problems as continuous transmission, avoiding undercutting and pointing of the pinion must be solved in the design. On the base of analyzing gearing with small tooth number, design points of the gearing with small tooth number are studied. Different minimum helix angle and corresponding modification coefficient of the pinion when the number of tooth of pinion is different. From the angle of practical using, the recommended practical number of teeth, helix angle and range of the modification coefficient of the pinion are given, which will provide scientific basis for selecting basic parameters appropriately.
2004, 18(Supplement).
Abstract:
High frequency response linear motor has been applied in all kinds of industry field, such as hard disk drive and non-circular turning. The linear motor applied in the non-circular CNC turning was researched. Because in order to obtain the non-circular part profile, the linear motor must move to-and-fro in high frequency, the dynamic goal tracking is very difficult. This research has been started for many years, and several control arithmetic (for example, PID and repetitive control) have been researched and applied, but the control accuracy has not been improved evidently. The new design method of all-digital-feedback linear servo motor is presented, and PID feedback + Iterative Learning Control for the linear motor control system is constructed. Experiment research indicates that the control performance has been improved greatly. This system has been applied the Non-circular CNC system.
High frequency response linear motor has been applied in all kinds of industry field, such as hard disk drive and non-circular turning. The linear motor applied in the non-circular CNC turning was researched. Because in order to obtain the non-circular part profile, the linear motor must move to-and-fro in high frequency, the dynamic goal tracking is very difficult. This research has been started for many years, and several control arithmetic (for example, PID and repetitive control) have been researched and applied, but the control accuracy has not been improved evidently. The new design method of all-digital-feedback linear servo motor is presented, and PID feedback + Iterative Learning Control for the linear motor control system is constructed. Experiment research indicates that the control performance has been improved greatly. This system has been applied the Non-circular CNC system.
2004, 18(Supplement).
Abstract:
The dexterous workspace is of significant importance in design of a planar manipulator. To determine the dexterous workspace of a planar 3-DOF parallel manipulator, the auxiliary linkages are constructed with the reference point of the moving platform as the fixed hinge. If the reference point lies in the dexterous workspace, the moving platform should be able to rotate around the reference point by the definition of the dexterous workspace and the platform becomes the crank in the auxiliary linkage. Based on the Grashof criteria for the auxiliary linkages, the conditions for the reference point to lie in the dexterous workspace are derived and the boundary of the dexterous workspace can then be drawn in a simple graphical method. Different examples are given to verify the effectiveness of the method and meanwhile the possible separation of the dexterous workspace is analyzed.
The dexterous workspace is of significant importance in design of a planar manipulator. To determine the dexterous workspace of a planar 3-DOF parallel manipulator, the auxiliary linkages are constructed with the reference point of the moving platform as the fixed hinge. If the reference point lies in the dexterous workspace, the moving platform should be able to rotate around the reference point by the definition of the dexterous workspace and the platform becomes the crank in the auxiliary linkage. Based on the Grashof criteria for the auxiliary linkages, the conditions for the reference point to lie in the dexterous workspace are derived and the boundary of the dexterous workspace can then be drawn in a simple graphical method. Different examples are given to verify the effectiveness of the method and meanwhile the possible separation of the dexterous workspace is analyzed.
2004, 18(Supplement).
Abstract:
The methods widely used to represent the motions data of mechanisms at present are not very direct. Two types of new methods, one scalar-based and one vector-based, are proposed to improve the visualization of the motions data, and their representing examples are also presented with planar four-bar mechanisms. The new methods could provide more intuitive graphical impressions on a global overview or local detail in a complete cycle and relationships between each variable.
The methods widely used to represent the motions data of mechanisms at present are not very direct. Two types of new methods, one scalar-based and one vector-based, are proposed to improve the visualization of the motions data, and their representing examples are also presented with planar four-bar mechanisms. The new methods could provide more intuitive graphical impressions on a global overview or local detail in a complete cycle and relationships between each variable.
2004, 18(Supplement).
Abstract:
The formulation of the inverse kinematics and dynamics of a novel 3-axis hybrid machine tools is presented. This machine tools is based on a 2-DOF parallel platform and serial kinematic chain. The position analysis is firstly performed. The velocity and accelera-tion formulas of the links and sliders are derived. The forces acting on the joints can be determined according to the force and moment equilibriums of the links. Subsequently the driving forces of the actuators are derived from the force equilibrium of the sliders. The sensitivities model construction of inverse kinematics and dynamics to the errors of motion model parameters are developed. The presented approach can also be applied to other less DOF parallel manipulators.
The formulation of the inverse kinematics and dynamics of a novel 3-axis hybrid machine tools is presented. This machine tools is based on a 2-DOF parallel platform and serial kinematic chain. The position analysis is firstly performed. The velocity and accelera-tion formulas of the links and sliders are derived. The forces acting on the joints can be determined according to the force and moment equilibriums of the links. Subsequently the driving forces of the actuators are derived from the force equilibrium of the sliders. The sensitivities model construction of inverse kinematics and dynamics to the errors of motion model parameters are developed. The presented approach can also be applied to other less DOF parallel manipulators.
2004, 18(Supplement).
Abstract:
The structure and operation principles of ocean wave twin-floater generator are presented. On the base of mechanical mathematical model, the interrelations of main parameters are analyzed. And harmonic drive gear is applied in the device. All will provide the theoretical base for further design of ocean wave twin-floater generator.
The structure and operation principles of ocean wave twin-floater generator are presented. On the base of mechanical mathematical model, the interrelations of main parameters are analyzed. And harmonic drive gear is applied in the device. All will provide the theoretical base for further design of ocean wave twin-floater generator.
2004, 18(Supplement).
Abstract:
A human-machine intelligent control system for grinding is proposed. The system integrates human brain intelligence with machine intelligence. First, the expert system based on neural network decides the initial grinding parameters. Second, the adaptation control system handles the grinding process through the multi-feed and setting overshoot optimization methods. Third, the human-machine interaction adaptation system and two fuzzy–neural networks revise the process parameters in real-time. The experiment of the external cylindrical grinding is conducted. The results show that human-machine intelligent control system is feasible, and can significantly increase grinding efficiency and quality.
A human-machine intelligent control system for grinding is proposed. The system integrates human brain intelligence with machine intelligence. First, the expert system based on neural network decides the initial grinding parameters. Second, the adaptation control system handles the grinding process through the multi-feed and setting overshoot optimization methods. Third, the human-machine interaction adaptation system and two fuzzy–neural networks revise the process parameters in real-time. The experiment of the external cylindrical grinding is conducted. The results show that human-machine intelligent control system is feasible, and can significantly increase grinding efficiency and quality.
2004, 18(Supplement).
Abstract:
Based on the theory of neural network, the nonlinear modeling of reliability model is discussed. Firstly, the general concept and basic method to set up reliability model is introduced. Secondly, the reliability model is deduced. Finally, the simulation result demonstrates the efficiency of the reliability model.
Based on the theory of neural network, the nonlinear modeling of reliability model is discussed. Firstly, the general concept and basic method to set up reliability model is introduced. Secondly, the reliability model is deduced. Finally, the simulation result demonstrates the efficiency of the reliability model.
2004, 18(Supplement).
Abstract:
A torsion hydraulic time-delay coupler is developed, which is used for buffering the reversing impact torque of the long-stroke petroleum pumping unit system. Through its hydraulic buffering function, this coupler converts the abrupt reversing rotation of the driving shaft into a smoothly and uniformly variable reversing rotation of the shaft of the working machine (the drum of the long-stroke pumping unit). According to the practical working conditions and the Bernoulli equation in fluid mechanics, the formulas for calculating the hydraulic pressure and the torque in reversing are derived. Then, through the energy method, the delay time and rotational angle are determined. Finally, the related factors that influence the relationship of torque versus delay time are analyzed by means of a program generated to calculate the results. The calculations show that this coupler produces an excellent buffering effect.
A torsion hydraulic time-delay coupler is developed, which is used for buffering the reversing impact torque of the long-stroke petroleum pumping unit system. Through its hydraulic buffering function, this coupler converts the abrupt reversing rotation of the driving shaft into a smoothly and uniformly variable reversing rotation of the shaft of the working machine (the drum of the long-stroke pumping unit). According to the practical working conditions and the Bernoulli equation in fluid mechanics, the formulas for calculating the hydraulic pressure and the torque in reversing are derived. Then, through the energy method, the delay time and rotational angle are determined. Finally, the related factors that influence the relationship of torque versus delay time are analyzed by means of a program generated to calculate the results. The calculations show that this coupler produces an excellent buffering effect.
2004, 18(Supplement).
Abstract:
A new method for vibration damping analysis of general multi-layered rectangular plates consisting of arbitrary number of layers of orthotropic materials has been developed by method of basic elastic equation and Tailor series. The solution for a multi-layered plate with simply supported edges has taken in series summation form and resonating. Affection of thickness of viscoelastic core and thickness of constrained layer has been considered and the solution of a calculation example has been got. Present method also could be used for mechanical performance and damping analysis of composite plates.
A new method for vibration damping analysis of general multi-layered rectangular plates consisting of arbitrary number of layers of orthotropic materials has been developed by method of basic elastic equation and Tailor series. The solution for a multi-layered plate with simply supported edges has taken in series summation form and resonating. Affection of thickness of viscoelastic core and thickness of constrained layer has been considered and the solution of a calculation example has been got. Present method also could be used for mechanical performance and damping analysis of composite plates.
2004, 18(Supplement).
Abstract:
The inverse Jacobian matrix of a robot contains highly useful information about the performances of the robot, for example about its accuracy and dexterity. Unfortunately these information are available only mostly through the eigenvalues of this matrix which are pose and design parameters dependent. Interval analysis based algorithms is presented that allow to extract useful information from any matrix such as minimal and maximal eigenvalues and minimal condition number.
The inverse Jacobian matrix of a robot contains highly useful information about the performances of the robot, for example about its accuracy and dexterity. Unfortunately these information are available only mostly through the eigenvalues of this matrix which are pose and design parameters dependent. Interval analysis based algorithms is presented that allow to extract useful information from any matrix such as minimal and maximal eigenvalues and minimal condition number.
2004, 18(Supplement).
Abstract:
A new type of top-coal caving hydraulic support and its characteristic are discussed. The multi-freedom mechanism of the support is simplified as a planar mechanism to get a direct analytic solution. The kinematic analysis of the support are made to present the equations which indicate the parametric relationship of geometry and motion of the components. The key formula deduced here can be used not only to virtual reality but also to practical application of the hydraulic supports. In order that the top beam of support can move horizontally, which makes the support work perfectly and effectively, the front and back legs must move at certain velocity coordinately. With the method of virtual design, the errors and faults are fined easily, many improvements are made in time, which makes the new hydraulic support developed successfully.
A new type of top-coal caving hydraulic support and its characteristic are discussed. The multi-freedom mechanism of the support is simplified as a planar mechanism to get a direct analytic solution. The kinematic analysis of the support are made to present the equations which indicate the parametric relationship of geometry and motion of the components. The key formula deduced here can be used not only to virtual reality but also to practical application of the hydraulic supports. In order that the top beam of support can move horizontally, which makes the support work perfectly and effectively, the front and back legs must move at certain velocity coordinately. With the method of virtual design, the errors and faults are fined easily, many improvements are made in time, which makes the new hydraulic support developed successfully.
2004, 18(Supplement).
Abstract:
The improved motion law combined of simple harmonic and trapezium has much more applied value in engineering for the jerk of which is continuous. The mathematical model of this improved motion law is rebuilt and the equations of displacement, velocity, acceleration and jerk as well as their relative parameters are concluded. From the eigenvalues of the optimized motion law it is concluded that it has clearly more stability than that is not improved.
The improved motion law combined of simple harmonic and trapezium has much more applied value in engineering for the jerk of which is continuous. The mathematical model of this improved motion law is rebuilt and the equations of displacement, velocity, acceleration and jerk as well as their relative parameters are concluded. From the eigenvalues of the optimized motion law it is concluded that it has clearly more stability than that is not improved.
2004, 18(Supplement).
Abstract:
Geared linkages are useful combined mechanisms, which can be formed by combining planar linkages with one or more pairs of gears. As a result output motions can be obtained with reversing, nonreversing without dwell or nonreversing with dwell. As an example consider the design of the regressive and irregressive two-gear four-bar linkages with prescribed dwell characteristics. First of all, the non-linear equations are derived from the instantaneous dwell conditions. Then a simplified algorithm is given, including relevant analytical solutions and the crank existing conditions, and the homotopy iteration method is introduced to solve the non-linear equations, all solutions can be found easily without initial value selection. Finally the numerical examples are provided.
Geared linkages are useful combined mechanisms, which can be formed by combining planar linkages with one or more pairs of gears. As a result output motions can be obtained with reversing, nonreversing without dwell or nonreversing with dwell. As an example consider the design of the regressive and irregressive two-gear four-bar linkages with prescribed dwell characteristics. First of all, the non-linear equations are derived from the instantaneous dwell conditions. Then a simplified algorithm is given, including relevant analytical solutions and the crank existing conditions, and the homotopy iteration method is introduced to solve the non-linear equations, all solutions can be found easily without initial value selection. Finally the numerical examples are provided.
2004, 18(Supplement).
Abstract:
The optimal design for a kind of speed changeable sheet-fed mechanism is researched based on gear-connecting rod mechanism, applying to high-speed press. A mathematic model of optimal design is built on the basis of analysis of theoretical analysis, the objective function is built based on the speed with which the sheet arriving the front lay, and the solving method is approached also. This kind of method of optimal design is correct and with a great value to application by being verified through an example.
The optimal design for a kind of speed changeable sheet-fed mechanism is researched based on gear-connecting rod mechanism, applying to high-speed press. A mathematic model of optimal design is built on the basis of analysis of theoretical analysis, the objective function is built based on the speed with which the sheet arriving the front lay, and the solving method is approached also. This kind of method of optimal design is correct and with a great value to application by being verified through an example.
2004, 18(Supplement).
Abstract:
The cracked rotor is a piecewise linear system due to the breath of crack in shaft with rotation. For the nonsmooth system, the motion equation is derived and solved with numerical integration method. From the result, it can be seen that there exists the grazing bifurcation in the response. The grazing bifurcation can give rise to jump between periodic motion, quasi-period from period, chaos and intermittent chaos.
The cracked rotor is a piecewise linear system due to the breath of crack in shaft with rotation. For the nonsmooth system, the motion equation is derived and solved with numerical integration method. From the result, it can be seen that there exists the grazing bifurcation in the response. The grazing bifurcation can give rise to jump between periodic motion, quasi-period from period, chaos and intermittent chaos.
2004, 18(Supplement).
Abstract:
A systematic methodology for the creation and classification of movable tooth gear mechanisms is introduced. The approach is partly enumerative and partly analytical. Two kinds of movable tooth gear drives are categorized and the kinematic mechanism structures are sketched and evaluated. The results are helpful in creative design of feasible mechanisms and the dimensional synthesis, kinematics and dynamics analyses, design optimization, and design detailings.
A systematic methodology for the creation and classification of movable tooth gear mechanisms is introduced. The approach is partly enumerative and partly analytical. Two kinds of movable tooth gear drives are categorized and the kinematic mechanism structures are sketched and evaluated. The results are helpful in creative design of feasible mechanisms and the dimensional synthesis, kinematics and dynamics analyses, design optimization, and design detailings.
2004, 18(Supplement).
Abstract:
For circular arced rotors in Roots blower, there are three different kinds of profile of the transverse section. The equations of the profiles of these three kinds of three-lobe circular arced rotor are derived in details in this article. The explicit expression of the radius of curvature of the profile and the maximum ratio of ra/a are derived. The characteristics of these three different kinds of circular arced rotors are discussed and compared. The equations of the helicoids of the helical rotor and the axial section of the milling cutter are derived. The cutting parameters and interference problem during cutting are discussed deeply.
For circular arced rotors in Roots blower, there are three different kinds of profile of the transverse section. The equations of the profiles of these three kinds of three-lobe circular arced rotor are derived in details in this article. The explicit expression of the radius of curvature of the profile and the maximum ratio of ra/a are derived. The characteristics of these three different kinds of circular arced rotors are discussed and compared. The equations of the helicoids of the helical rotor and the axial section of the milling cutter are derived. The cutting parameters and interference problem during cutting are discussed deeply.
2004, 18(Supplement).
Abstract:
According to the characteristics of gear trains, tri-color-graph is introduced to describe to the structure. Further more tri-color-tree is proposed to describe structure characteristics of gear trains. Concepts, such as parent array, leaf couple array, and leaf couple parent array, are defined to express digitally the structure of gear trains. A new method of type synthesis of gear trains is presented. The key of the method is to develop the higher class of gear trains by adding basic structure chain to the original train. This method is effective and is easy to perform with computer.
According to the characteristics of gear trains, tri-color-graph is introduced to describe to the structure. Further more tri-color-tree is proposed to describe structure characteristics of gear trains. Concepts, such as parent array, leaf couple array, and leaf couple parent array, are defined to express digitally the structure of gear trains. A new method of type synthesis of gear trains is presented. The key of the method is to develop the higher class of gear trains by adding basic structure chain to the original train. This method is effective and is easy to perform with computer.
2004, 18(Supplement).
Abstract:
A new approach for decomposing the planar geared linkage mechanisms (GLM) into a series of sequential independent basic simple links and dyad link groups is presented, which can be realized in a computer automatically. According to the tricolor graph, which is introduced to describe the topological relationship between the kinematic pairs and the links in a GLM, the criteria and procedure of GLMs' structure decomposition by the theory of type transformation are established, which make the structure decomposing procedures of GLMs and planar linkage mechanisms (PLM) unified. Finally, the examples of structure decomposition are given. The research serves as the basis for establishing the general method for the kinematic analysis of GLMs.
A new approach for decomposing the planar geared linkage mechanisms (GLM) into a series of sequential independent basic simple links and dyad link groups is presented, which can be realized in a computer automatically. According to the tricolor graph, which is introduced to describe the topological relationship between the kinematic pairs and the links in a GLM, the criteria and procedure of GLMs' structure decomposition by the theory of type transformation are established, which make the structure decomposing procedures of GLMs and planar linkage mechanisms (PLM) unified. Finally, the examples of structure decomposition are given. The research serves as the basis for establishing the general method for the kinematic analysis of GLMs.
2004, 18(Supplement).
Abstract:
According to the work conditions of a press machine, the theoretical and experimental research on the starting rapidity and the even speed are carried out for an electro-hydraulic proportional position control system (EHPPCS) with a single-rod cylinder. Numerical simulations are carried out in the toolbox SIMULINK of MATLAB. In experiments, PID control law is adopted, because the PID control algorithm is simple in operation, is characteristics of good computer real-time control, and possesses the good adaptability of changing parameters of control system itself and controlled object. The results of simulations and experiments show that the EHPPCS has excellent starting rapidity, excellent even speed and higher position control precision.
According to the work conditions of a press machine, the theoretical and experimental research on the starting rapidity and the even speed are carried out for an electro-hydraulic proportional position control system (EHPPCS) with a single-rod cylinder. Numerical simulations are carried out in the toolbox SIMULINK of MATLAB. In experiments, PID control law is adopted, because the PID control algorithm is simple in operation, is characteristics of good computer real-time control, and possesses the good adaptability of changing parameters of control system itself and controlled object. The results of simulations and experiments show that the EHPPCS has excellent starting rapidity, excellent even speed and higher position control precision.
2004, 18(Supplement).
Abstract:
Grasp planning is one of key issues for robotic dexterous hands to accomplish the desired tasks. A possible technical solution is master-slave operation. Human hand and robot hand operate as the master and the slave, respectively. The motion mapping from human hand to robot hand is presented and implemented in a virtual environment so that the robot hand can accomplish the grasp tasks by human demonstrations. The simulation results illustrate the validity of the method.
Grasp planning is one of key issues for robotic dexterous hands to accomplish the desired tasks. A possible technical solution is master-slave operation. Human hand and robot hand operate as the master and the slave, respectively. The motion mapping from human hand to robot hand is presented and implemented in a virtual environment so that the robot hand can accomplish the grasp tasks by human demonstrations. The simulation results illustrate the validity of the method.
2004, 18(Supplement).
Abstract:
A new cutter's control method is produced, which realizes the one-side machining of the globoidal cam. A example is presented, and the result shows the new method has great practical value. A new type of point contact mechanism is presented, a hyperboloidal roller replaces for the cylindrical roller in assembly, the point contact with hyperboloidal roller overcomes the defects of linear engagement and enhances the mechanism's toleration of and adaptability to error. Using the method can help to improve the positioning and indexing accuracy and whole performance of the mechanism.
A new cutter's control method is produced, which realizes the one-side machining of the globoidal cam. A example is presented, and the result shows the new method has great practical value. A new type of point contact mechanism is presented, a hyperboloidal roller replaces for the cylindrical roller in assembly, the point contact with hyperboloidal roller overcomes the defects of linear engagement and enhances the mechanism's toleration of and adaptability to error. Using the method can help to improve the positioning and indexing accuracy and whole performance of the mechanism.
2004, 18(Supplement).
Abstract:
One kind of fitting feature and information connection among assembly parts is presented. At first, analyze the topological and fitting connection of parts that consist of the assembly body. Then create the fitting connection chain and vector matrix of parts. At last, build the fitting parts chain that consists of the close assembly loop based on fitting connection chain and vector matrix of parts. After obtaining the assembly parts chain, the system can analyze the fitting parts chain and the dimensional relation of all fitting parts, and then obtain the dimension chain of the close assembly loop based on the dimensional relation, the fitting connection chain and vector matrix of parts. The designer can uniquely determine the assembly parts chain of product assembly body by using this method, it is efficient to analyze and obtain the parts and dimension chain of complex assembly body.
One kind of fitting feature and information connection among assembly parts is presented. At first, analyze the topological and fitting connection of parts that consist of the assembly body. Then create the fitting connection chain and vector matrix of parts. At last, build the fitting parts chain that consists of the close assembly loop based on fitting connection chain and vector matrix of parts. After obtaining the assembly parts chain, the system can analyze the fitting parts chain and the dimensional relation of all fitting parts, and then obtain the dimension chain of the close assembly loop based on the dimensional relation, the fitting connection chain and vector matrix of parts. The designer can uniquely determine the assembly parts chain of product assembly body by using this method, it is efficient to analyze and obtain the parts and dimension chain of complex assembly body.
2004, 18(Supplement).
Abstract:
A computerized method is presented to calculate the spatial cam surfaces without their analytic expressions. Given the definitions of the follower surface and the assembly configuration as well as the motions, a computerized model and algorithm are developed to compute the cam surfaces through transformation of the enveloping condition. This new idea makes it possible to construct a truly versatile CAD/CAM program for whatever type cam mechanisms. This new method is illustrated with an example.
A computerized method is presented to calculate the spatial cam surfaces without their analytic expressions. Given the definitions of the follower surface and the assembly configuration as well as the motions, a computerized model and algorithm are developed to compute the cam surfaces through transformation of the enveloping condition. This new idea makes it possible to construct a truly versatile CAD/CAM program for whatever type cam mechanisms. This new method is illustrated with an example.
2004, 18(Supplement).
Abstract:
The working process of a client-server system to simulate and control remote robot via Internet is described. OpenGL is chosen to accomplish robot dynamic simulation according to the information of robot position and motion. And robot remote control protocol (RRCP) based on TCP/IP to accomplish remote communication between manipulator and robot is designed. The manipulator at remote place can simulate the motion state of robot and control robot to perform correlative operations according to the feedback information. Moreover, a new method of solving the problem of delay is showed. Firstly, since the information that is transmitted to client by server is only about parameters of robot motion, data are less than image information. Secondly, reasonable threshold values at server are set, thus the dynamic information of robot is encapsulated and sent to client only when the parameter values are higher than the threshold values and not every moment. So few data are transmitted on network, congestion is reduced, and the problems of delay and losing data packets are improved.
The working process of a client-server system to simulate and control remote robot via Internet is described. OpenGL is chosen to accomplish robot dynamic simulation according to the information of robot position and motion. And robot remote control protocol (RRCP) based on TCP/IP to accomplish remote communication between manipulator and robot is designed. The manipulator at remote place can simulate the motion state of robot and control robot to perform correlative operations according to the feedback information. Moreover, a new method of solving the problem of delay is showed. Firstly, since the information that is transmitted to client by server is only about parameters of robot motion, data are less than image information. Secondly, reasonable threshold values at server are set, thus the dynamic information of robot is encapsulated and sent to client only when the parameter values are higher than the threshold values and not every moment. So few data are transmitted on network, congestion is reduced, and the problems of delay and losing data packets are improved.
2004, 18(Supplement).
Abstract:
With the widespread application of computer, control and microelectronics into mechanism, generalized executive mechanism has become a branch of modern mechanisms. The state-of-the-art of existing knowledge base of mechanical system and mechatronic system are analyzed. The composition system of knowledge base of generalized executive mechanism is developed by means of functional analysis method. From the motion characteristics viewpoint, the content of the knowledge base is discassed. Applied examples about selected scheme in the knowledge base are provided. Generalized executive mechanism is also the important component part of mechatronic system. The knowledge base can effectively aid conceptual design of mechatronic system and support product creative design.
With the widespread application of computer, control and microelectronics into mechanism, generalized executive mechanism has become a branch of modern mechanisms. The state-of-the-art of existing knowledge base of mechanical system and mechatronic system are analyzed. The composition system of knowledge base of generalized executive mechanism is developed by means of functional analysis method. From the motion characteristics viewpoint, the content of the knowledge base is discassed. Applied examples about selected scheme in the knowledge base are provided. Generalized executive mechanism is also the important component part of mechatronic system. The knowledge base can effectively aid conceptual design of mechatronic system and support product creative design.
2004, 18(Supplement).
Abstract:
Aimed at bad robustness of taphole drill of 1 200 m3 blast furnace in a iron and steel works, overcon-straint of the mechanism is analyzed, which is closed-chain six-bar mechanism. Then its structure design to eliminate overconstraint is discussed, and non-overconstraint basic links combinations and their configuration pattern are presented, combined with working characteristic and movement precision requirement of taphole drill, desired configuration pattern is selected. In this way, the ma-chine runs smoothly, its efficiency is high.
Aimed at bad robustness of taphole drill of 1 200 m3 blast furnace in a iron and steel works, overcon-straint of the mechanism is analyzed, which is closed-chain six-bar mechanism. Then its structure design to eliminate overconstraint is discussed, and non-overconstraint basic links combinations and their configuration pattern are presented, combined with working characteristic and movement precision requirement of taphole drill, desired configuration pattern is selected. In this way, the ma-chine runs smoothly, its efficiency is high.
2004, 18(Supplement).
Abstract:
The kinematics of 3-DOF planar parallel symmetrical mechanisms—3RRR are studied with kinematical influence coefficient method. Some novel kinematical performance indices for parallel mechanism including velocity and acceleration indices are presented based on the kinematics influence coefficient matrices. According to these performance indices, the kinematical performance of mechanisms—3RRR is studied and the relationship between the design parameters and its kinematical performance are given by performance atlases which would be helpful for mechanism design.
The kinematics of 3-DOF planar parallel symmetrical mechanisms—3RRR are studied with kinematical influence coefficient method. Some novel kinematical performance indices for parallel mechanism including velocity and acceleration indices are presented based on the kinematics influence coefficient matrices. According to these performance indices, the kinematical performance of mechanisms—3RRR is studied and the relationship between the design parameters and its kinematical performance are given by performance atlases which would be helpful for mechanism design.
2004, 18(Supplement).
Abstract:
A piece of cross-disciplinary research is introduced where textile science and garment engineering are associated with the development of garment handling devices. A domestic chore is focused on, the process in domestic ironing is reviewed ,and the technology which is potentially useable for the automatic ironing where the most frequent task is to handle a piece of fabric and a pair of garment is investigated. This requires the study of garment handling and its corresponding devices for the task. Garment handling is categorised into several steps and common handling operations are highlighted. The analysis results in the categorisation of gripping and handling devices with potential applications to domestic automation. This leads to the study of garment folding and unfolding with relevant techniques and algorithms. Some potential technology in multi-fingered robotic hands are presented.
A piece of cross-disciplinary research is introduced where textile science and garment engineering are associated with the development of garment handling devices. A domestic chore is focused on, the process in domestic ironing is reviewed ,and the technology which is potentially useable for the automatic ironing where the most frequent task is to handle a piece of fabric and a pair of garment is investigated. This requires the study of garment handling and its corresponding devices for the task. Garment handling is categorised into several steps and common handling operations are highlighted. The analysis results in the categorisation of gripping and handling devices with potential applications to domestic automation. This leads to the study of garment folding and unfolding with relevant techniques and algorithms. Some potential technology in multi-fingered robotic hands are presented.
2004, 18(Supplement).
Abstract:
Paper machine has a broad market in China. Improving product or developing new product is very important for the enterprise to keep the advantage in the competition. Technology evolution of TRIZ can be used to forecast the future technology of the product. Using the patterns and lines of technology evolution, the future technologies of the paper machine parts, such as former, press roll and doctoring device, are proposed. These future technologies can guide the designer to the right direction of developing the new product.
Paper machine has a broad market in China. Improving product or developing new product is very important for the enterprise to keep the advantage in the competition. Technology evolution of TRIZ can be used to forecast the future technology of the product. Using the patterns and lines of technology evolution, the future technologies of the paper machine parts, such as former, press roll and doctoring device, are proposed. These future technologies can guide the designer to the right direction of developing the new product.
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