遗传算法在直流伺服系统摩擦补偿中的应用

针对直流伺服系统中存在的摩擦干扰问题,提出了一种基于遗传算法(GA)进行摩擦补偿的设计方案.首先根据直流伺服系统的摩擦特性建立摩擦模型,再将摩擦补偿引入直流伺服系统的反馈控制结构中,获取伺服电机的位置误差.采用遗传算法对摩擦补偿模型进行系统辨识,使摩擦补偿量在数值上不断地逼近实际的摩擦干扰,并利用摩擦补偿量来抵消摩擦给伺服系统带来的影响,遗传算法中目标函数的选择考虑了系统在过渡过程和稳态时的控制要求.经过参数优化得出的摩擦补偿模型,弥补了以往直流伺服系统受摩擦干扰影响动、静态性能较差的缺陷,从而保证了伺服电机具有较高的跟踪精度.仿真结果表明,该方案与无摩擦补偿情况相比,直流伺服电机转速响应的调节时间缩短了0.12 s,稳态误差降低了1%,系统具备较强的抗摩擦干扰能力和参数鲁棒性.

Application of Genetic Algorithm to Friction Compensation in Direct Current Servo Systems

Focusing on the problem of the friction disturbances in direct current(DC) servo system,a scheme of friction compensation with genetic algorithm(GA) is proposed.A friction model is established according to the friction characteristics of a DC servo system;then,the friction compensation is introduced to the feedback control structure of DC servo system to calculate the position error of the servo motor.Genetic algorithm is adopted to identify the friction compensation model,and to make the quantity of friction compensation approximates to the practical friction disturbance unceasingly,so that the influence of friction on the servo system is eliminated.Moreover,the objective function of genetic algorithm is selected according to the control demands in the transition process and steady state of the system.The friction compensation model obtained from optimized parameters compensates the low dynamic and static performance of the previous DC servo systems due to friction disturbance,and ensures that the servo motor has higher track precision.Simulation results demonstrate that,compared to the case without friction compensation,the adjusting time of rotating speed response of the DC servo motor is decreased by 0.12 s,and the static error is lowered by 1%,meanwhile the system has better restraint ability against friction disturbance and parameter robustness.