Research On Fuzzy Sliding Mode Controller And Its Application To Electromechanical System

The electromechanical system is more and more complicated with the rapid development of science and technique, and the requirement of precision, respond time, stability and adaptive ability is also improved. However, due to the non-linear dynamic characteristic of electromechanical system, external disturbance and parameter uncertainty, it is difficult to be control precisely such nonlinear-system when adopting the conventional control arithmetic. In this paper, two control arithmetics based on the sliding mode controller are proposed for the purpose of improving the robustness and real-time requirement, respectively. The sliding and global stability of these two controllers are approved in terms of Lyapunov full quadratic form. The fuzzy logic adaptive system is introduced to tune the parameters of sliding mode controller. The performance of controlled system is improved effectively by adopting the proposed fuzzy sliding mode controllers.However, the expensive computing requirement of the complicated algorithm in fuzzy sliding mode controller (FSMC) may limit its on-line application to the complicated electromechanical system. Therefore, the enhanced fuzzy sliding mode controller (EFSMC) is proposed to improve the real-time requirement of the non-linear controlled system. The region-wise linear fuzzy adaptive system is adopted to tune the gain of the sliding mode controller, which can force the states of controlled system hit the sliding mode surface, quickly. The number of the fuzzy rules for the fuzzy logic adaptive tuner is also reduced. As a result, the complexity of FSMC is reduced, which ensure the real-time requirement of the controlled system.In addition, in order to improve the robustness of the controlled system and alleviate the chattering phenomenon, the dynamic sliding mode controller with fuzzy adaptive tuning (FADSMC) is proposed in this paper. For a real controlled system, the external disturbance and measuring noise must be considered during the design of the controller. Therefore, it is difficult to obtain the smooth control output for the conventional controller. Especially, for a class of controlled system which require the control force and its change as the control input of the servo system, the discontinuous jump will occur when the (U(k)-U(k-1))/Δt=ΔU is adopted to compute the change of control force. Then, the controlled system will not work stably and the robustness and control precision is reduced. However, the change of control force can be obtained by adopting the dynamic sliding mode controller. The control force can be easily obtained from the integral of its change. A smoother control force can be obtained and the chattering phenomenon is also alleviated. The fuzzy adaptive system is introduced to improve the robustness and stability of the controlled system.In this paper, three simulation systems and an experiment system are adopted to demonstrate the proposed controllers. (1) A 2 degree of freedom (DOF) polar manipulator and a 3-DOF parallel manipulator simulation system have been carried out to demonstrate the performance of the proposed the proposed EFSMC controller. (2) The proposed FADSMC controller is applied in the active suspension system to improve its performance. The simulation results are compared with that of the passive suspension, LQG control active suspension and CSMC control active suspension system. (3) The rapid prototype experiment of the automated clutch of AMT based on the dSPACE is designed to demonstrate the performance of the proposed EFSMC and FADSMC. The simulation and experimental results show that the better performance can be obtained by adopting the proposed controllers.