Research On High Performance Control Method Of Electro-hydraulic Position Servo System Based On Disturbance Observer

The electro-hydraulic position servo system is a common hydraulic servo system widely used in national defense and civil industry.Its main task is to drive the inertial load through a double output rod hydraulic cylinder controlled by a servo valve,so that the inertial load can track the predetermined reference trajectory as much as possible.Based on the high-performance requirements of the electro-hydraulic position servo system in engineering practice,it is very important to achieve high-precision tracking control of the electro-hydraulic position servo system.However,in the long-term use of electro-hydraulic position servo systems in practical engineering,the wear and tear of internal components,different inertia load sizes,and working environments at different temperatures can all cause changes in system parameters,thereby affecting the performance and effectiveness of controllers containing system parameters.In addition,in actual working environments,there are often various external disturbances that prevent the electro-hydraulic position servo system from accurately driving the inertial load and accurately tracking the desired trajectory.To address the above issues,traditional control algorithms cannot achieve satisfactory results.Therefore,the research on how to suppress external disturbances and the impact of system parameter changes on control performance of electro-hydraulic position servo systems is of great significance.The main research content of this article is as follows:1.A control strategy for an electro-hydraulic position servo system with strong disturbances is studied.A mathematical model is established for an electro-hydraulic position servo system with strong disturbances.On this basis,an adaptive super-twisting sliding mode control method based on finite-time generalized extended state observer is proposed.Firstly,the parametric uncertainties,external disturbances,and unmodeled dynamics in the electro-hydraulic position servo system are considered as the comprehensive disturbance of the system.A finite-time generalized extended state observer is designed to observe the comprehensive disturbance in the electro-hydraulic position servo system in real time,and it is used in the design of the controller to suppress the influence of the comprehensive disturbance on the control performance of the system.Secondly,an adaptive super-twisting sliding mode controller is proposed,which not only suppresses the chattering problem existing in the traditional sliding mode control,but also makes the system have better rapidity and convergence effects.Subsequently,the finite-time convergence of the tracking error of the closed-loop system is verified using Lyapunov stability theory.Finally,the effectiveness of the proposed method is verified by comparing simulation results.2.A control strategy of an electro-hydraulic position servo system with parametric uncertainties and composite disturbances is studied.Firstly,in order to achieve finite-time convergence of the tracking error of the closed-loop system,a nonsingular fast terminal sliding surface is designed,which can have better rapidity and convergence effects than traditional terminal sliding surfaces.Secondly,the electro-hydraulic position servo system is divided into two subsystems containing comprehensive disturbances,and disturbance observers are respectively established for real-time observation.Based on the backstepping method,a nonsingular fast terminal sliding mode controller based on disturbance observers is designed.Then it is proved by Lyapunov stability theory that the tracking error of the system can converge to the bounded neighborhood in finite time.Finally,the effectiveness of the proposed algorithm is verified through simulation.3.A control strategy for an electro-hydraulic position servo system with prescribed performance control is studied.In order to further address parametric uncertainties and composite disturbances in the electro-hydraulic position servo system,an extended sliding mode observer with parametric adaptive law is constructed by integrating an adaptive nonlinear feedback tracking control design to observe the composite disturbances in real time.In order to ensure that the tracking error of the system can be limited to a given region,an improved prescribed performance function and an error transformation function are proposed.A nonlinear adaptive feedback controller based on an extended sliding mode observer is designed using the backstepping method.In the process of controller design,a tracking differentiator is introduced to estimate the derivative of the virtual control law and solve the "differential explosion" problem that may occur in the traditional backstepping method.Then,it is demonstrated through Lyapunov stability theory that the proposed control method can strictly limit the system tracking error to a prescribed range.Finally,the effectiveness of the proposed control strategy is verified through simulation.