Research On Full-state Constraints And Dynamic Surface Control Of Electro-hydraulic Servo System

The electro-hydraulic servo control system is a time-varying,strong nonlinear uncertain system.In actual control,these uncertainties are difficult to obtain accurate mathematical models,and the control objects are often complicated and there are external disturbances and parameters.In industrial production and application,it is very necessary to protect the system and personal safety as well as the ecological environment,so the actual control system must operate under certain constraints.Therefore,an important research field in the electro-hydraulic servo system control problem is the boundedness of the full state error.In the electro-hydraulic servo system of this study,the full-state error constraint indicates the tracking accuracy of the hydraulic cylinder position,the rate limit of the hydraulic cylinder response,and the feasible load pressure boundary of the hydraulic cylinder,ensuring that the state constraint is not destroyed is to ensure the normal operation of the system.In this study,a dynamic surface control method for electro-hydraulic servo system based on obstacle Lyapunov function is proposed to realize the full-state error constraint under uncertain nonlinear conditions.Firstly,the working principle of electro-hydraulic servo system is analyzed,and the electro-hydraulic servo system model is constructed as a state space strict feedback model.Secondly,according to the required position tracking accuracy,the rate limit of the hydraulic cylinder response and the load pressure boundary,the BLF constraint control method is used to constrain the system state error under the required constraints.In the reverse iteration,the dynamic surface method is used instead of the continuous derivation of the dummy variable to design the stability function,thus avoiding the "differential explosion" phenomenon occurring in the reverse recursive process and suppressing the system's severe flutter response.In addition,the proposed full-state error constraint and dynamic surface control method are simulated and verified,and compared with the traditional electro-hydraulic servo system PID controller.The simulation results of the hydraulic parameters under ideal conditions are considered.The simulation results of the uncertainty parameters and external disturbances can be verified from the simulation results,and the designed full-state error constraint controller can achieve the expected performance requirements.Finally,this study verified the validity and reliability of the full-state error constraint and dynamic surface control method of the electro-hydraulic servo system designed in the previous chapters.A set of mechanical arm test platform and integrated data acquisition system were built and implemented on the platform.The semi-physical simulation experiment verified the correctness of the mathematical model and theoretical analysis through experiments,and confirmed the improvement of the performance of the electro-hydraulic servo system.This study also accumulated a large amount of experience and experimental data for the improvement of advanced control methods and system upgrades of electro-hydraulic servo systems.At the same time,the platform built in this study can debug and verify the advanced control algorithms of new designs that may be needed in the future.