1995 Vol.8(2)
Display Mode： |
1995, 9(2).
Abstract:
A numerical analytic process is suggested combing direct boundary element method with discrete vortex method and internal flow in cross-flow fan calculated. The process considers not only function of impeller, but also effect of volute casing. Internal flow field of cross-flow fan is practically measured, and results compared with that from calcuation. It shows that the process is expected to be used in predicting performances of fluid machinery.
A numerical analytic process is suggested combing direct boundary element method with discrete vortex method and internal flow in cross-flow fan calculated. The process considers not only function of impeller, but also effect of volute casing. Internal flow field of cross-flow fan is practically measured, and results compared with that from calcuation. It shows that the process is expected to be used in predicting performances of fluid machinery.
1995, 9(2).
Abstract:
The magnetic fluid is used as working medium in pilot stage of electro-hydraulic servo amplifier. Utlizing the magnetization viscous character of the fluid, a new type of electro-hydraulic servo amplifier without any moving parts in its pilot stage has been developed. This research provides a way for improving the frequency property and reliability of electro-hydraulic servo elements.
The magnetic fluid is used as working medium in pilot stage of electro-hydraulic servo amplifier. Utlizing the magnetization viscous character of the fluid, a new type of electro-hydraulic servo amplifier without any moving parts in its pilot stage has been developed. This research provides a way for improving the frequency property and reliability of electro-hydraulic servo elements.
1995, 9(2).
Abstract:
Existing approaches to automatic assembly planning often lead to combinatorial explosion. When the parts composing the assembly increase in number, computer-aided planning becomes much slower than manulal planning. Efforts to reduce the computing time by taking into account various constraints and criteria to guide the search for the optimal plan requires too much input information, so as to offset the convenience of automatic assembly planning. In addition, as the planner becomes more conplicated, such efforts often fail to reach the objective. This papter presents a new concept-"unit", asserting that the internal structure of an assembly is hierachical. Every disassembly operation only handles several units, no matter how many parts are involved. Furthermore, the scenario of disassembly is brought to light. It relates to only two key data-the liaison type and the assembly direction. The computational cast of this approach is roughly proportional to the number of parts. A planner, implementing these principles can generate the optimal assembly plans dramatically faster than the known approaches.
Existing approaches to automatic assembly planning often lead to combinatorial explosion. When the parts composing the assembly increase in number, computer-aided planning becomes much slower than manulal planning. Efforts to reduce the computing time by taking into account various constraints and criteria to guide the search for the optimal plan requires too much input information, so as to offset the convenience of automatic assembly planning. In addition, as the planner becomes more conplicated, such efforts often fail to reach the objective. This papter presents a new concept-"unit", asserting that the internal structure of an assembly is hierachical. Every disassembly operation only handles several units, no matter how many parts are involved. Furthermore, the scenario of disassembly is brought to light. It relates to only two key data-the liaison type and the assembly direction. The computational cast of this approach is roughly proportional to the number of parts. A planner, implementing these principles can generate the optimal assembly plans dramatically faster than the known approaches.
1995, 9(2).
Abstract:
Polishing ceramics with a bonded diamond abrasive and fine-grain soft abrasives was carried out. The different material removal mechanism of the two kinds of abrasives was pointed out through the measurement of the material removal rate vs.polishing time and polishing speed repectively. XPS examination proved that a mechanochemical reaction took place when polishing Sialon, a kind of non-oxide ceramics, with the Cr2O3 bonded abrasives disc.
Polishing ceramics with a bonded diamond abrasive and fine-grain soft abrasives was carried out. The different material removal mechanism of the two kinds of abrasives was pointed out through the measurement of the material removal rate vs.polishing time and polishing speed repectively. XPS examination proved that a mechanochemical reaction took place when polishing Sialon, a kind of non-oxide ceramics, with the Cr2O3 bonded abrasives disc.
1995, 9(2).
Abstract:
A simple analytical model method for dynamics of robotic manipulators is proposed. Problem of deriving model matrix elements is transformed into problem of solving for driving force and driving torque under specified condition by recursive dynamic equations. Expressions of reaction force in arbitrary joint in numeric-symbolic form are also derived. The properties of model matrices are given. Corresponding software which can recognize and manipulate symbols is developed and can be used to generate model and real-time code of robotic dynamics.
A simple analytical model method for dynamics of robotic manipulators is proposed. Problem of deriving model matrix elements is transformed into problem of solving for driving force and driving torque under specified condition by recursive dynamic equations. Expressions of reaction force in arbitrary joint in numeric-symbolic form are also derived. The properties of model matrices are given. Corresponding software which can recognize and manipulate symbols is developed and can be used to generate model and real-time code of robotic dynamics.
1995, 9(2).
Abstract:
The forms of the vibration disturbances inside the epicyclic gear train are analyzed. The frequency equations for the inner disturbances of the epicyclic gearing with one or two degrees of freedon have been built. The latter of them is a 3-dimension problem and the range of the disturbance frequencies covers a series of planes inside the 3-dimension coordinates. As a result, the chances to lead to the system resonance are developed. The calculating results indicate that in the design process of the shaft system, the chances of resonance can be reduced by tunning the dynamic parameters and the structure of the system.
The forms of the vibration disturbances inside the epicyclic gear train are analyzed. The frequency equations for the inner disturbances of the epicyclic gearing with one or two degrees of freedon have been built. The latter of them is a 3-dimension problem and the range of the disturbance frequencies covers a series of planes inside the 3-dimension coordinates. As a result, the chances to lead to the system resonance are developed. The calculating results indicate that in the design process of the shaft system, the chances of resonance can be reduced by tunning the dynamic parameters and the structure of the system.
1995, 9(2).
Abstract:
The vibrational power flow in the beam-plate assemblies and then with the isolators is investigated using analytical "power flow" approach based on the some concepts of mechannical mobility and structural dynamics. Theoretical expressions of the power flow in the structures are given and examined. The numerical results of the expressions are good agreements with the measuring results obtained by the technique of vibration intensity. On the basis of these results, possible ways of reducing the vibrational power flow in the structures suggested.
The vibrational power flow in the beam-plate assemblies and then with the isolators is investigated using analytical "power flow" approach based on the some concepts of mechannical mobility and structural dynamics. Theoretical expressions of the power flow in the structures are given and examined. The numerical results of the expressions are good agreements with the measuring results obtained by the technique of vibration intensity. On the basis of these results, possible ways of reducing the vibrational power flow in the structures suggested.
1995, 9(2).
Abstract:
The vibration response formulas of the mechanical system under the affect of the vari-frequency exciting force are deduced. It is proved by the theoretical analysis and experimental results that the vibration response amplitude of the mechanical system under the affect of the vari-frequency exciting force is far smaller than that under the affect of the constant frequency exciting force on condition that the exciting force amplitudes are just the same; while the vari-frequency rate χincreases to 5 Hz per second the vibration amplitude will decrease to 10% only as low as that under the affect of the constant frequency exciting force. All these conclusions will be of significance for revealing the mechanism of suppressing chatter in vari-speed cutting and analyzing the experimental results of sine-wave scanning exciting test.
The vibration response formulas of the mechanical system under the affect of the vari-frequency exciting force are deduced. It is proved by the theoretical analysis and experimental results that the vibration response amplitude of the mechanical system under the affect of the vari-frequency exciting force is far smaller than that under the affect of the constant frequency exciting force on condition that the exciting force amplitudes are just the same; while the vari-frequency rate χincreases to 5 Hz per second the vibration amplitude will decrease to 10% only as low as that under the affect of the constant frequency exciting force. All these conclusions will be of significance for revealing the mechanism of suppressing chatter in vari-speed cutting and analyzing the experimental results of sine-wave scanning exciting test.
1995, 9(2).
Abstract:
An preliminary design tool—LLTCA (lubrication and loaded tooth contact analysis) for spiral bevel and hypoid gears is presented, which combines the thermal-EHL analysis with LTCA. The LTCA is used to predict the contact behavior, the geometry of tooth surfaces, normal load, and kinematics for thermal-EHL analysis between the mating surfaces. From the results of thermal-EHL the designer can predict the lubrication performance which usually include the oil film forming ability, film pressure and the increment of temperature. In the LLTCA model the contact behavior, lubrication performance, running condition and tooth geometry which is the resultant of manufacturing parameters are all considered.
An preliminary design tool—LLTCA (lubrication and loaded tooth contact analysis) for spiral bevel and hypoid gears is presented, which combines the thermal-EHL analysis with LTCA. The LTCA is used to predict the contact behavior, the geometry of tooth surfaces, normal load, and kinematics for thermal-EHL analysis between the mating surfaces. From the results of thermal-EHL the designer can predict the lubrication performance which usually include the oil film forming ability, film pressure and the increment of temperature. In the LLTCA model the contact behavior, lubrication performance, running condition and tooth geometry which is the resultant of manufacturing parameters are all considered.
1995, 9(2).
Abstract:
An element based on the harmonic functions for performing vibration analysis of linkages was developed to propose the matrix-transit equations and the kineto-elastrodynamics (KED) different equations. Method and the KED equations was continllous undertaken by the modal superposition approach. The results from those equations include the quasistatic parst and the dynamic parts. The dynamic parts equaled to the developing parts of the computation accurations.
An element based on the harmonic functions for performing vibration analysis of linkages was developed to propose the matrix-transit equations and the kineto-elastrodynamics (KED) different equations. Method and the KED equations was continllous undertaken by the modal superposition approach. The results from those equations include the quasistatic parst and the dynamic parts. The dynamic parts equaled to the developing parts of the computation accurations.
1995, 9(2).
Abstract:
The increasing demand on robotic system performance leads to the use of advanced control strategies. This paper proposes a method of nonlinear feedback control introducing fuzzy inference into model-following adaptive control for the nonlinear robot manipulator systems. The fuzzy inference is introduced to treat the nonlinearties of the control systems. Furthermore, the stability of the system is discussed by the fuzzy stability theory based on the Lyapunov's direct method. In the closed loop, the robotic system asymptotically converge to the reference trajectory with a prescribed transient response.
The increasing demand on robotic system performance leads to the use of advanced control strategies. This paper proposes a method of nonlinear feedback control introducing fuzzy inference into model-following adaptive control for the nonlinear robot manipulator systems. The fuzzy inference is introduced to treat the nonlinearties of the control systems. Furthermore, the stability of the system is discussed by the fuzzy stability theory based on the Lyapunov's direct method. In the closed loop, the robotic system asymptotically converge to the reference trajectory with a prescribed transient response.
1995, 9(2).
Abstract:
The using situation at present is summarized about the seal for process thick liquid pump. It is reasonalbe that sealing scheme is composed of secondary impeller and centrifugal block stop seal. Main formulas are deduced and some problems are pointed out on design and calcualtion of centrifugal block stop seal.
The using situation at present is summarized about the seal for process thick liquid pump. It is reasonalbe that sealing scheme is composed of secondary impeller and centrifugal block stop seal. Main formulas are deduced and some problems are pointed out on design and calcualtion of centrifugal block stop seal.
1995, 9(2).
Abstract:
The topographic information of a closed world is expressed as a graph. The plural moving objects which go and back in it according to a single moving strategy are supposed. The moving strategy is expressed by numerical valuse as a decision table. Coding is performed with this table ad chromosomes, and this is optimized by using genetic algorithm. These environments were realized on a computer, and the simulation was carried out. As the result, the learning of the method to act so that moving objects do not obstruct mutually was recognized, and it was confirmed that these methods are effictive for optimizing moving strategy.
The topographic information of a closed world is expressed as a graph. The plural moving objects which go and back in it according to a single moving strategy are supposed. The moving strategy is expressed by numerical valuse as a decision table. Coding is performed with this table ad chromosomes, and this is optimized by using genetic algorithm. These environments were realized on a computer, and the simulation was carried out. As the result, the learning of the method to act so that moving objects do not obstruct mutually was recognized, and it was confirmed that these methods are effictive for optimizing moving strategy.
1995, 9(2).
Abstract:
The influences of joints'error, motion history, speed and robot posture on repeatability are analyzed and the mathemaical expressions of the quantity, direction and distribution of the stochastic positional error are derived. Using this model the magnitude and direction of the stochastic positional error afer any motion can be preestimated and compensated.
The influences of joints'error, motion history, speed and robot posture on repeatability are analyzed and the mathemaical expressions of the quantity, direction and distribution of the stochastic positional error are derived. Using this model the magnitude and direction of the stochastic positional error afer any motion can be preestimated and compensated.
E-mail Alerts
