Papers by Author: Jun Wei Li

Abstract: The switch reluctance motor (SRM) speed control system is often difficult to control due to its nonlinearities and parameter variations. In this paper, a fuzzy logic control (FLC) system has been presented to speed control of the SRM. The control system is composed of speed controller and current controller. The main task of the speed controller is to provide the appropriate control signal to the current controller based on the difference between the desired speed and the actual speed of the motor. In the speed control part, the fuzzy controller is used to reject the unknown and uncertain parameters in the SRM and in the load torque. The current controller evaluates the difference between the actual and the desired phase current and implements hysteresis current control. Simulation results demonstrate the effectiveness of the proposed control strategy under different operating conditions of the SRM.

Abstract: A neuro-fuzzy control (NFC) system is developed to control the suspension system of vehicle due to its nonlinearity and parameter variations. A neural network (NN) is used to adjust the premise parameters and the consequent parameters in fuzzy logic control (FLC). Simulation results by using NFC are compared with those of the conventional PID controller and passive suspension system. Based on the simulation, it can be concluded that the neuro-fuzzy controller shows a good performance in both passenger comfort and vehicle handing in comparison to the conventional PID controller and passive suspension system.

Abstract: A coordinated control strategy based on Direct Yaw Moment Control (DYC) and slip rate control was proposed aiming at improving vehicle stability. The system was divided into two layers: an upper layer and a lower layer. DYC was the upper-layer control, which calculates the additional yaw moment exerted on the vehicle based on the working condition of the vehicle. A simplified arithmetic of transferring additional yaw moment to desired slip rate was adopted in order to achieve differential braking. Slip rate controller was the lower-layer control that exerts braking force on the braking wheels to achieve the desired slip rate and to achieve desired yaw moment.

Abstract: Vehicle reference model with two degree of freedom and multi-body vehicle dynamic model are set up at first. This paper presents a Fuzzy control strategy to deal with the nonlinear, time-varying characteristics of the system, which can control the feedback of yaw rate and side slip angle. The simulation results show that the Fuzzy control method can remarkably enhance the handling stability and safety of the vehicle in complex road and driving conditions.

Abstract: Based on the vehicle dynamic model and it’s parameters, the drive train arrangement is chosen composed of power batteries, an electric motor and transmission, and the components’ performance parameters are determined according to the design requirement of performance indexes. The model of the electric vehicle is built, and the simulation and analysis of vehicle performance indexes, such as the ability to accelerate, top speed, climbing performance and the driving range, are conducted. The simulation results show that the performance index of the electric vehicle can fully meet the design requirement.

Abstract: Based on the analysis of two kinds of torsion absorber of automobile power train, a power train idling vibration model with nine degrees of freedom is established, the generalized Jacobin algorithms and the compiled Matlab procedures are used to calculate the idling natural frequency and idling natural vibration model. The results show that the dual mass flywheel torsion absorber can keep the power train from idling resonance compared with the clutch torsion absorber and play a good role in attenuating the low frequency torsion vibration of power train.

Abstract: A two degrees of freedom nonlinear dynamics model of self-excited vibration induced by dry-friction of brake disk and pads is built firstly, the numerical method is taken to study the impacts of damping on automobile brake groan. The calculation result shows that the variation of damping coefficient and has different influence on automobile brake groan. and all have A critical value, when damping coefficient greater or less than the critical value the brake disk and pad possess the different vibration state respectively.