Chen Zhi-mei

A new antiwindup speed controller for induction motor drive system

The windup phenomenon appears and results in performance degradation when the proportional-integral (PI) speed controller output is saturated for the motor drive system. A new antiwindup speed controller is proposed to improve the speed control performance of the motor drive system. Based on the internal model control (IMC) method, the proposed controller is designed, the parameters of which are expressed directly in the system parameters and the desired closed loop bandwidth. This simplifies the speed controller design procedure, and trial-and-error can be avoided. Some simulated results are provided to demonstrate the effectiveness of the proposed controller.

A control scheme based on discrete time-varying sliding surface for position control systems

A sliding mode control scheme for second-order discrete system is proposed using the time-varying sliding surface instead of the fixed sliding surface. The time-varying sliding surface is designed first to pass arbitrary initial states, and subsequently move towards a final sliding surface by rotating. The sliding surface rotating procedures are presented in detail. The proposed control scheme is applied to a position control system. Simulation results show that the scheme provides high performance dynamic characteristics, and is insensitive to uncertainties including parameter variations and external disturbance in the whole control process.

Terminal Sliding Mode Control for Multi-degree-of-Freedom Robot Based on Genetic Algorithm

According to trajectory tracking of robot, a method of a terminal sliding model controller based on genetic algorithms is presented. By using genetic algorithm to select the optimum parameters of fast terminal sliding mode, the system state variables are guaranteed to reach the sliding mode manifold quickly and stay on it all the time in finite time, and then the trajectory tracking control is realized. A simulation study is made on a two-degree-of-freedom robot system, and the results show that the system has good dynamic performance and good robustness, and the chattering can be effectively eliminated.

A new method of sliding mode control and application to AC servo system

A new sliding mode control method is presented in this article for AC servo system. Combining fuzzy control and sliding mode control, the chattering of sliding mode control is solved. Introducing an integral element, the stable-state precision is enhanced. The sliding surface designed by means of this method is a time-varied one, which has powerful robustness to parameter variations and external disturbances. Simulation study results show that this method is correct and effective.

Integral sliding mode variable structure control based on fuzzy logic

Based on fuzzy logic, a method of integral sliding mode variable structure control is presented, which is applied to a class of linear system in the presence of disturbances and model uncertainties. This method is formed by combing sliding mode variable structure control with fuzzy control, furthermore an integral control is introduced into it in order to eliminate steady-state error and improve control precision. Simulation results show that the control system not only exhibits strong robustness, excellent tracking characteristics and controlling effects, but also avoids the chattering phenomenon.