关键词: 六自由度并联平台, 液压伺服系统, 比例-积分-微分（PID）控制, 遗传算法

Abstract: The single channel electro-hydraulic servo system is a system with nonlinear and time-varying, and has a small damping ratio, parameter varies a lot, high degree of nonlinear characteristics. The traditional PID control is hard to meet the requirements of the control precision of 6-DOF parallel platform. In order to meet the requirements of system control accuracy, this paper uses a genetic algorithm to optimize the parameters of PID controller, in the  mathematical model of single channel electro-hydraulic servo system. The simulation results show that the performance of the control system improves a lot, proves the feasibility and effectiveness of the improved algorithm, overcomes the drawback of traditional PID parameters setting time consuming, provides the effective method to deal with the practical problem and the adaptive （robustness） also improves.

Key words: 6-Degree Of Freedom（DOF） parallel platform, hydraulic servo system, Proportion Integration Differentiation（PID） control, genetic algorithm