4-SPS(PS)并联机构模糊自适应滑模控制系统设计

Design of Fuzzy-Adaptive Sliding Mode Control System for the 4-SPS(PS) Parallel Mechanism

针对并联机构传统控制方式轨迹跟踪精度误差较大的缺陷,提出了一种基于4-SPS(PS)并联机构的动力学方程和模糊自适应(Fuzzy-Adaptive SMC)滑模控制器的控制系统。首先,基于螺旋理论及反螺旋理论,设计了一种4-SPS(PS)并联机构,并采用微运动法(Micro-Motion Method)对机构的运动学方程进行了探讨。其次,基于机构的动力学方程,结合模糊自适应算法,设计了一种新型滑模控制器(SMC),模糊自适应算法的作用是实时地修正系统的不确定和非线性项参数,有效抑制了SMC系统的抖振现象。最后,建立了机构的系统仿真框图和实验平台,分别对机构进行仿真分析和实验研究。结果表明:模糊自适应滑模变结构控制器的轨迹跟踪精度高,鲁棒性强,稳态误差小,从而验证了该新型SMC控制器的有效性。

The conventional controller for parallel mechanism has a defect that the trajectory tracking error is larger, a control system was designed based on the dynamic equation of 4-SPS（PS） parallel mechanism and the fuzzy-adaptive sliding mode controller. Firstly, a 4-SPS（PS） parallel mechanism was proposed based on screw and anti-screw theory, then the kinematic equation of mechanism was discussed by using micro-motion method. Secondly, based on the dynamic equation of mechanism, a new SMC controller was presented by combining the fuzzy-adaptive algorithm with the sliding mode controller, and the fuzzy-adaptive algorithm is introduced to modify the uncertain and nonlinear parameters of the system, accordingly it can effectively solve the chattering problem in sliding mode control system. Finally, the simulation diagram of manipulator and experimental platform were established, and the simulation analysis and experimental research were carried out. The results show that the fuzzy-adaptive sliding mode controller has high precision, strong robustness and small steady-state error, which verifies the effectiveness of new SMC controller.