Research On Sliding Mode Control Of Electro-hydraulic Proportional Position Control System For Nuclear Robot

Electro-hydraulic proportional position control system is a kind of control system between electro-hydraulic switch control system and electro-hydraulic servo control system.It has strong environmental adaptability and is easy to maintain.Applying electro-hydraulic proportional technology to nuclear robot can improve its ability to adapt to nuclear radiation environment and system stability.In order to connect the end effector with the tool converter smoothly and accurately,the electro-hydraulic proportional position control system of the nuclear robot needs to track the desired trajectory accurately.The existing electro-hydraulic proportional position control system is highly nonlinear and the load is uncertain,the traditional linear control methods are difficult to meet the need of control precision,hence it is of great significance to study the sliding mode control of electro-hydraulic proportional position control system with good robustness and strong anti-jamming ability.The main contents of this thesis are as follows:(1)The development status of nuclear robot and electro-hydraulic proportional position control system is analyzed systematically.The basic principle of PID control algorithm and sliding mode control algorithm are summarized.The cause of chattering in sliding mode control algorithm and its solution are expounded.(2)The structure and operating parameters of the electro-hydraulic proportional position control system for nuclear robot are studied.The state space equation of the electro-hydraulic proportional control system is established by derivation of the mechanical balance equation,the dynamic flow characteristic equation of electro-hydraulic proportional valve and the flow continuity equation of hydraulic cylinder.(3)The sliding mode controller is designed,and the asymptotic stability of the system is studied by Lyapunov direct method.The position tracking of hydraulic cylinder is simulated and analyzed by Matlab/Simulink software,and the control parameters of sliding mode controller are optimized to restrain its chattering.(4)The experimental platform of the automatic tracking of the bucket rod hydraulic cylinder of the nuclear robot is built,and the PID control program and the sliding mode control program are compiled by using Lab VIEW/Mathscript.The trajectory tracking ability of the two control algorithms to the electro-hydraulic proportional position control system is compared and analyzed.The practicability and control performance of the sliding mode controller are verified by the experimental results.Simulation and experimental results show that,compared with the traditional PID control algorithm,the sliding mode control algorithm can improve the tracking performance and control precision of the electro-hydraulic proportional position control system of the nuclear robot,and improve the control precision and performance of the tool converter for automatic docking,which is an important basis for further autonomous control of the nuclear robot.