Integrated Design Of Polynomial Nonlinear Modeling And Control Of Electro-hydraulic Servo Systems

In this paper,the polynomial nonlinear modeling and control of electro-hydraulic servo system is designed based on the actual electro-hydraulic servo console.It mainly includes two parts:the design and implementation of the polynomial nonlinear control method and the design and implementation of the mixed policy value iterative control method.In the design of the polynomial nonlinear control method and its experimental scheme,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 H∞ 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 of the control process and does better in disturbance rejection.The design method proposed in this section provides a feasible scheme for the practical application of nonlinear H∞ control in the field of electrohydraulic servo system control.In the design of mixed policy value iterative control and its experimental scheme,firstly,a polynomial nonlinear H∞ control law is redesigned,which can ensure that the system has nonlinear control H∞ performance index,and the solution method of the control law is given.Secondly,referring to the policy network and value network of reinforcement learning,value iterative algorithm is added in the process of solving the polynomial nonlinear H∞ control law.The problem of solving the polynomial nonlinear H∞ control law is transformed into a single objective polynomial global optimization problem which can be solved by genetic algorithm,so as the mixed policy value iterative control is proposed.Thirdly,the PID control parameters of the electrohydraulic servo system are optimized by genetic algorithm as a comparison with the mixed policy value iterative control.Finally,the proposed control law is applied to the polynomial nonlinear model of the electro-hydraulic servo console.The experimental results show that,compared with the polynomial nonlinear H∞ control law and PID control optimized by genetic algorithm,mixed policy value iterative control law has stronger robustness and control performance.The two parts above,from the design of theoretical methods to the actual,simulation experiments,fully validate the effectiveness of the two design schemes,which lays the foundation for designing a nonlinear H∞ control system for an actual electro-hydraulic servo system.