1998 Vol.11(2)

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MICROBIOLIGICALLY INFLUENCED CORROSION ON WELD OF STAINLESS STEEL 304L
1998, 12(2).
[Abstract](2135) [PDF 294KB](27)
Abstract:
The influence of welding defects on MIC (microbiologically influenced corrosion) was studied. The open circuit potential (OCP) was measured during MIC test. It was found that OCP shifted to a higher level when the system was inoculated with bacteria and it decreased dramatically when MIC started. Among a series of welding defects golden heat tint was found the most susceptible to MIC. The tubercles over pitting were observed with SEM. Some elements inside of the tubercles were analysed with EDXA. Microbiological analysis of a corroded and a non-corroded sample revealed no significant difference between them with the exception of the number of the manganeseoxidising bacteria.
RESEARCH AND APPLICATION OF AS-CAST WEAR RESISTANCE HIGH CHROMIUM CAST IRON
1998, 12(2).
[Abstract](2142) [PDF 209KB](239)
Abstract:
The influence of alloy elements, such as boron and sillicon, on the microstructure and propertise of as-cast high chromium cast iron is studied. The results show that boron and silicon have a great effect on the mechanical properties and the wear resistance. Through proper addition of boron and silicon, the properties of as-cast high chromium cast iron can be improved dffectively. Through analyzing the distribution of elements by scanning electron microscope, it has been shown that the addition of boron and silicon lowers the mass fraction of chromium saturated in as-cast austenite, and makes it unstable and liable to be transformed into martensite. The as-cast high chromium cast iron with proper content of boron and silicon is suitable for the manufactrue of lining for asphalt concrete mixer and its wear resistane is 14 times that of lining made of low alloy white cast iron.
CHARACTERISTICS OF LOW TEMPERATURE ION PLATING TiN COATINGS
1998, 12(2).
[Abstract](2120) [PDF 213KB](168)
Abstract:
The TiN coatings were deposited onto the low carbon steel substrates with different temperatures (150, 250, 350 and 450 ℃), using hollow cathode discharge (HCD) ion plating method. The measurments of the microhardness and wear resistance of the coatings show that the hardness value slowly increases and the wear resistance remains almost unchanged with increasing the substrate temperature from 150℃ to 450℃. The reason for effect of the substrate temperature on the properties and morphologies of the coatings was investigated by means of X-ray diffraction and scanning electron microscope (SEM).
NEW APPROACHES FOR COMPUTING DYNAMIC LOAD-CARRYING CAPACITY OF MULTIPLE COOPERATING ROBOTIC MANIPULATORS
1998, 12(2).
[Abstract](2143) [PDF 196KB](162)
Abstract:
A novel unified method for computing the dynamic load-carrying capacity (DLCC) of multiple cooperating robotic manipulators is developed. In this method, the kinematic constraints and the governing dynamic equations of the multiple robor system are formulated in the joint space by using the method of transference of dependence from one set of generalized coordinates to another, and the virtual work principle, which includes the readily available dynamics and joint torques of individual manipulators, and the dynamic of payload. Based on this dynamic model, the upper limit of the DLCC at any points on a given trajectory is obtained by solving a small-size linear programming problem. This method is conceptually straightforward, and it is applicable also to the cases of multi-fingered robot hands and multi-legged waliing machines.
WHEELBASE PREVIEW OPTIMAL CONTROL FOR ACTIVE VEHICLE SUSPENSIONS
1998, 12(2).
[Abstract](2127) [PDF 228KB](353)
Abstract:
An algorithm in which the optimal control law takes the advantage of the correlation between front and reaqr inputs, I.e., wheelbase preview information, for an active vehicle suspension design is described. Based on simulations, the potential improvements from wheelbase preview and the effects of preview time are investigated.
RESEARCH ON BEHAVIORS OF ELECTRORHEOLOGICAL FLUID-BASED SEMIACTIVE ROBOT FINGERTIPS
1998, 12(2).
[Abstract](2161) [PDF 230KB](191)
Abstract:
A new design of robot gripper with electrorheological fluid (ERF) semiactive tips is described. There are two remarkable properties using this fingertip. One is the higher lifting capability at little grasp force, which can realize stable grasp. Another is the damping controllable which can be used for controlling contact forces. A viscoelastic-plastic model for normal direction of the fingertip is proposed to explore the contact behavior. The electric field strength is induced into the dynamic model of contact trasition for simulations. The simulation results and conclusions are given.
ESTIMATION OF OBJECT GRAVITY AND WRENCH EXERTED ON OBJECT USING MULTIFINGERED HAND WITH FORCE/TORQUE SENSORS
1998, 12(2).
[Abstract](2132) [PDF 226KB](117)
Abstract:
From the point of view of real application of multifingered hand, the problem of estimating the gravity of a graped object and the wrench exerted on the object by the external environment, using multifingered hand equipped with force/troque sensors, is addressed. At first the problem is modeled mathematically by the concept of wrench, then gravitational effect of fingertips is taken into accounted to eliminate the biasing effect in real implementation. On experimental system HKUST HAND, some experiments are carried out to implement and verify the proposed approach. This is an introduction to real application of multifingered hand, such as assembly of parts.
PREDICTION OF MICROSTRUCTURE EVOLUTION DURING HOT EXPANDING-EXTRUSION FORMING OF RESTRAINING RINGS
1998, 12(2).
[Abstract](2169) [PDF 160KB](91)
Abstract:
A mathematic model for dynamic and static recrystallization of Mn18Cr18N steel is presented. Hot expanding-extrusion forming and air cooling process of 600 MW retaining ring has been simulated by the combination of thermos-coupled rigid viscoplasitic FEM with this model, and grain size distribution on cross-section of ring is shown. The essential results can be provided for use of the new technique.
FUZZY STABILITY ANALYSIS OF MODE COUPLING CHATTER ON CUTTING PROCESS
1998, 12(2).
[Abstract](2166) [PDF 163KB](92)
Abstract:
The influence of fuzzy unceratinty factors is considered on the analysis of chatter occurring during machine tool cutting process. Using fuzzy mathematics analysis methods, a detailed discussion over fuzzy stability analysis problems is presented related to the mode coupling chatter with respect to intrinsic structure fuzzy factors, and the possibility distribution of the fuzzy stabillity cutting range and the confidence level expressions of the fuzzy stability cutting width are given.
APPLICATION OF STEP IN CAD/CAPP INTEGRATION
1998, 12(2).
[Abstract](2176) [PDF 251KB](65)
Abstract:
A brif discussion of the content and methodology of STEP is given, and STEP based strategies for CAD/CAPP information integration is pointed out. A STEP based feature technology in which a threelayer feature definition is included is discussed, the content of feature information is analyzed and a stratified CAD feature library is shown. On these bases, a commonly shared part information model is proposed. The architecture of the integrated CAD/CAPP system is presented.
APPROACH TO FAULT ON-LINE DETECTION AND DIAGNOSIS BASED ON NEURAL NETWORKS FOR ROBOT IN FMS
1998, 12(2).
[Abstract](2190) [PDF 252KB](112)
Abstract:
Based on radial basis function (RBF) neural networks, the healthy working model of each subsystem of robot in FMS is established. A new approach to fault on-line detection and diagnosis according to neural networks model is presented. Fault double detection based on neural network model and threshold judgement and quick fault identification based on multi-layer feedforward neural network model and threshold judgement and quick fault identification based on multi-layer feedforward neural networks are applied, which can meet quickness and reliability of fault detection and diagnosis for robot in FMS.
EXPERIMENTAL STUDY ON INFLUENCE OF SUPPLIED PRESSURE FLUCTUATION ON OUTPUT ARACTERISTIC OF PRESSURE CONTROL SYSTEM OF ROLLING MILL
1998, 12(2).
[Abstract](2172) [PDF 193KB](132)
Abstract:
The infulence of supplied pressure fluctuation on output accracy for the electro-hydraulic pressure control system of the rolling mill is discussed. Based on the bond graph theory and experimental study, the relationship between the variation of system output pressure and the supplied pressure fluctuation and the influence of the system bandwidth on system output pressure are provided. A theoretical base for determining the allowable fluctuation range of pressure and accurate design of constant pressure source system is obtained.
STUDY ON MODULAR FAULT TREE ANALYSIS TECHNIQUE WITH CUT SETS MATRIX METHOD
1998, 12(2).
[Abstract](2159) [PDF 211KB](142)
Abstract:
A new fault tree analysis (FTA) computation method is put forth by using modularization technique in FTA with cut sets matrix, and can reduce NP (Nondeterministic polynomial) difficulty effectively. This software can run in IBM-PC and DOS 3.0 and up. The method provides theoretical basis and computation tool for application of FTA technique in the common engineering system.