基于GA的直线伺服系统H_∞优化控制的研究

Research on H_∞ Optimization Control Based on Genetic Algorithm for Linear Servo System

针对永磁直线伺服系统存在的不确定性扰动,提出基于遗传算法(GA)的H∞混合灵敏度控制方法。根据永磁直线伺服系统的数学模型,对电流环采用PI控制,用根轨迹法来确定控制器的参数;以参考输入和扰动作为系统的输入向量,考虑系统对参考输入的跟踪和对扰动输入的抑制,将速度控制器设计归结为H∞混合灵敏度问题;在选择多个加权函数时,以性能指标作为相应的适应度函数,采用遗传算法选取加权函数,设计伺服系统的H∞优化控制器。对系统进行计算机仿真。仿真结果表明,用该方法设计的系统,其抑制扰动和跟踪给定信号的性能得到改善,满足高性能数控机床永磁直线伺服系统控制的要求。

A H∞ mixed sensitivity control method based on genetic algorithm （GA） was mentioned aiming at the uncertain disturbance of permanent magnet linear servo system. According to the mathematical model of permanent magnet linear servo system, the current loop was controlled by PI control and the controller parameters were determined by root locus method. Taking reference inputs and disturbances as the system input vectors, considering tracking of the reference input and suppressing of disturbance input, the speed controller design was come down to H∞ mixed sensitivity problem. When selecting multiple weighting functions, taking the performance indicators as the corresponding fitness function, genetic algorithm was used to select the weighting functions to design H∞controller of servo system. The simulation of the system was carried out. The simulation results show that the system designed using this method has good anti-disturbance performance and tracking performance for given signal. It meets the control requirement of high-performance CNC machine tool permanent magnet linear servo system.