改进遗传算法PID在电液伺服系统的应用

Application of Improved Genetic Algorithm PID Controller in Electro-Hydraulic Servo System

由于电液伺服系统在工业控制过程中存在非线性、参数时变等问题,运用常规的PID控制不能保证系统的控制精度,因此设计了一种新型的PID控制方法。该方法体系结构由常规PID控制器和改进遗传算法两部分组成,主要是运用改进遗传算法实现对PID控制参数的自适应调节,提高对电液伺服系统的实时调节控制能力。其中改进遗传算法对遗传算法父代的选择方式和交叉变异机理,分别运用了精英保留机制的轮盘赌策略和自适应调节策略,改善了遗传算法容易陷入局部极值的缺点,提高了算法的全局搜索能力和收敛速度,进而实现了对PID控制参数的寻优整定。将该方法应用于电液伺服系统数学模型中,并利用MATLAB/SIMULINK进行仿真。结果表明,该方法具有良好的鲁棒性和自适应性,改善了系统的超调、震荡等特性,提高了控制系统动态响应速度和稳态精度,对参数时变、非线性控制系统具有很好的应用价值。

Because of the non-linearity and parameter time-varying in the process of industrial control,the conventional PID control cannot guarantee the control precision of the system,a new PID control method is designed. The architecture of this method is composed of conventional PID controller and improved genetic algorithm. It mainly uses the improved genetic algorithm to realize the adaptive adjustment of PID control parameters and to improve the real-time regulating and control capability of electro-hydraulic servo system. The improved genetic algorithm has used the roulette strategy and adaptive adjustment strategy of the elite retention mechanism respectively into the selection mode of parent and cross mutation mechanism of genetic algorithm,the shortcoming of easily falls into local extreme value in genetic algorithm is overcome,and the global searching capability and convergence speed are improved,thus the optimizing tuning of the PID control parameter can be implemented. The method is applied in the mathematical model of electro-hydraulic servo system and simulated by MATLAB/SIMULINK. The results show that the method has good robustness and adaptability,and improves the overshoot and oscillation features and the dynamic response speed and steady-state accuracy of the control system; these are of great value to the parameter time-varying and nonlinear control systems.