Zhang Jian-wu

Perturbation analyses for the postbuckling of simply supported rectangular plates under uniaxial compression

In this paper, applving perturbation method to von Kármán nonlinear large deflection equations of plates by taking deflection as perturbation parameter, the posibuckling behavior of simply supported rectangular plates under uniaxial compresion is investigated. Two types of in-plane boundary conditions are now considered and the effects of initial imperfections are also studied. It is found that the theoretical results are in good agreement with experiments.The method suggested in this paper which has not been found in previous papers is rather simple and easy for the postbuckling analysis of rectangular plates.

FUZZY NEURAL NETWORKS CONTROL OF A SEMI-ACTIVE SUSPENSION SYSTEM WITH DYNAMIC ABSORBER

For a semi-active suspension design, an important subject is to determine the control law which can achieve good performance both in ride and handling performance. Because of its superiority in non-linear control systems and capability of learning on-line, the fuzzy neural networks (FNNs) control scheme is proposed in this paper for a semi-active suspension system with dynamic absorber. The quarter vehicle model is described by a nonlinear system with three DOF subject to irregular excitation from a road surface and FNNs control scheme is employed. The on-line learning of FNNs to optimize fuzzy inference system is presented. Four kinds of methods, including passive suspension respectively with and without dynamic absorber, semi-active suspension respectively using fuzzy control and FNNs control, are investigated by computer simulation and comparison is made. It is indicated that the semi-active suspension system employing the FNNs control strategy proposed in this paper is more effective in improving the performance of vehicles by comparing with other methods and also shown how the addition of a dynamic absorber reduces the excessive vibration of the wheel mass by a great amount. For the covering abstract see ITRD E108169.

The rapid development of hybrid ISG control system by on-line debugging system

An integrated starter/generator (ISG) hybrid propulsion system is being developed that has a parallel configuration. A small engine which is used to supply power approximately equal to the average load power is coaxially configured with an induction motor with an external rotor which is used to supply the peaking power required by the required peaking load of vehicle. The motor can also absorb the excess power of the engine while the load power is less than the peak power. The excess power will be used to charge the vehicular battery pack to keep state of charge (SOC) of the battery pack as the regenerative braking power. With the electrically assist principle, a controller for hybrid ISG assemble has been developed, and a fuzzy logic control strategy used to control the ISG system and motor was discussed. The control system for hybrid propulsion system is responsible for collecting information relative to vehicle and judges the load rate of engine and motor, and finally decides the operating state and rate of power distribution between engine and motor. By optimizing the system efficiency and minimizing fuel consumption and emission, the optimal performance will be reached. Electronics control unit (ECU) of hybrid propulsion system controls ECUs of engine, motor and automatic mechanics transmission (AMT), and monitors the state of battery management system (BMS), they communicate with each other and exchange information by control area network (CAN) bus interface. In order to accelerate developing process of hybrid propulsion system, a rapid developing system called on-line debugging and programming software has been developed. This system runs in PC, and communicates with the ECU of hybrid propulsion system by serial communication interface (SCI) RS232, but the ECU of hybrid propulsion system communicates with the ECUs of engine, AMT, BMS and accessory by CAN bus. This system mainly includes the following functions: (1) field test and bench test, (2) parameter calibration, (3) on-ling debugging for HEV, AMT and CAN bus, (4) vehicle dynamics simulation, (5) on-line programming, (6) troubleshooting etc. Those functions may achieve the rapid development on hardware and software of control system for hybrid propulsion system. In addition, the on-line debugging and programming system can monitor state information of overall system and modify parametric maps or update control program onboard by the on-line debugging or programming function. Based on the on-line debugging software package developed by our group at HUBEI automotive industries institute, the hybrid ISG assemble and its controller have been designed. Finally, experiments verify that the system is feasible and reliable, it can save 30%-50% developing time for the ISG hybrid propulsion system.

Real-time estimation algorithm of vehicle lateral speed

A real-time estimation algorithm of lateral speed for center of the vehicle mass, which is called composite method, and used for vehicle stability control (VSC) system, is introduced. The algorithm makes full use of advantages of direct integration method of the lateral speed modeling estimation method. Based on the composite estimation model, the equations of continuity state are dispersed, and the calculation of feedback matrix for closed loop observer and coefficient matrix of discrete model are presented. The test results show that the composite method draws the advantages of both the direct integration method(the insensitivity) and lateral speed modeling estimation method(non-accumulated errors). The composite method can successfully avoid disadvantages of both the direct integration method and the modeling estimation method, and show the better performance.

WCET analysis for gasoline engine control

An architecture and worst-case execution time (WCET) analysis is proposed for vehicle real-time control unit. In the WCET analysis, modeling, scheduling and verifying are implemented. This paper investigates into single cylinder gasoline engine control system, which is featured by complex state-varying temporal parameters. The worst case happens when engine speed increases to maximum. For timing analysis, a coordination transformation from absolute time axle to crankshaft rotational phase is applied. The established workload model includes six tasks distributed on three processors. An updated triple as [P E d] is defined to specify temporal parameters, and an interconnection graph is compiled to describe the timing and resource dependency explicitly. A local nonpreemptive timer-triggered (LNPTT) scheduling algorithm is designed and verified in terms of feasibility concerned both prerequisite and sufficient conditions. Simulations and experiments for LNPTT, compared with round-robin scheduler, are implemented. The results show, the established real-time model is suitable for WCET analysis, and LNPTT is feasible and reliable for gasoline engine control system, while round-robin scheduler is unreliable for this issue.

On the refined first-order shear deformation plate theory of Kármán type

A new refined first-order shear-deformation plate theory of the Kármán type is presented for engineering applications and a new version of the generalized Kármán large deflection equations with deflection and stress functions as two unknown variables is formulated for nonlinear analysis of shear-deformable plates of composite material and construction, based on the Mindlin/Reissner theory. In this refined plate theory two rotations that are constrained out in the formulation are imposed upon overall displacements of the plates in an implicit role. Linear and nonlinear investigations may be made by the engineering theory to a class of shear-deformation plates such as moderately thick composite plates, orthotropic sandwich plates, densely stiffened plates, and laminated shear-deformable plates. Reduced forms of the generalized Kármán equations are derived consequently, which are found identical to those existe in the literature.

Study on Expressing Principles of Semantics in Product Design

Product semantics is a tool in product design to generate newer, better and more meaningful forms. Consumer preference and perception of products strongly influence a products acceptability. Both are expressed by words that may be studied using product semantics. As product semantics spreads rapidly in product design, it faces more interrogative challenges from the lack of empirical evidence to substantiate the claims of some product semanticists. Based on the study of product semantics design methods, this paper presents several principles which should be followed for expressing semantics in product design. Then, it explains the meanings of these principles by some examples. These principles should be helpful in product design.

Discrete control of electrical controllable clutches using /spl delta/ operators

A discrete model described by delta transformation converges to its continuous counterpart as sample time T/spl rarr/0. This paper introduces delta transformation into the clutch engaging process control in automatic mechanical transition (AMT) of an automobile. A minimum-time controller and a pole-zero cancellation controller are designed respectively to track the ideal angle velocity of an output shaft. Compared with z transformation, delta transformation has better performance for round off noise caused by finite word length, but more calculations are needed.