电液伺服系统多项式非线性建模与控制一体化设计

常规电液伺服系统PID控制无法克服非线性因素影响,存在跟踪准确性和鲁棒性问题.因此,本文提出电液伺服系统多项式非线性H_∞控制律设计方法,改进电液伺服系统的控制性能与鲁棒性.首先利用多项式非线性模型对电液伺服系统进行系统辨识,得到以误差作为状态变量的多项式非线性模型;然后设计多项式非线性控制律,证明所提出控制律可以保证系统从干扰至控制输出L₂增益小于等于设定值,并且在系统干扰为零时保证误差全局渐进收敛,同时给出了控制律的求解方法.最后对提出的控制律进行实验验证.实验结果表明:相较于常规PID控制,多项式非线性控制律能够改善实验台伺服缸控制过程的瞬态响应,具有更好的抗干扰能力.本文提出的设计方法为非线性H_∞控制在电液伺服系统控制领域的实际应用提供了可行方案.

Integrated design of polynomial nonlinear modeling and control of electro-hydraulic servo systems

The conventional electro-hydraulic servo system PID control cannot overcome the influence of nonlinear factors,and has tracking accuracy and robustness problems.Therefore,a polynomial nonlinear H_∞control law design method is proposed to improve the control performance and robustness of electro-hydraulic servo systems.Firstly,a polynomial nonlinear model is used to identify the electro-hydraulic servo system,and a polynomial nonlinear model with tracking error as state variables is obtained.Secondly,the polynomial nonlinear control law is designed.The control law can ensure the system has L₂-gain from disturbance to output less than or equal to a set value,and global asymptotic convergence of the error is achieved when the system disturbance is zero.The solution method of the control law is given as well.Finally,the proposed control law is experimentally verified.The experimental results show that,compared with the conventional PID control,the polynomial nonlinear control law can improve the transient response during the control process and does better in disturbance rejection.The design method proposed in this paper provides a feasible scheme for the practical application of nonlinear H_∞ control in the field of electro-hydraulic servo system control.