Design Of Servo Control System For Bionic Hydraulic Quadrupedrobot

The hydraulic bionic quadruped robot has become a hot issue in the field of robotics research due to its high load capacity,strong terrain adaptability,large output torque,high motion accuracy,and strong power density.Servo system is the core key component of the quadruped robot actuator.When the external load and temperature change,the model parameters are prone to drift change,which brings challenges to the high precision control of the servo system.The traditional PID control method is difficult to meet the control requirements of this type of uncertain model.In this paper,the mathematical model of the servo valve,hydraulic cylinder and other components in the hydraulic bionic quadruped robot servo system is established,and the two-stage series servo valve controller and hydraulic cylinder controller are established using the auto-disturbance control method.First,a tracking differentiator is established to simulate the tracking command and the differential value of the tracking command,and the high-frequency noise of the system is filtered by the low-pass characteristic of the differentiator.Secondly,an expanded state observer is designed to observe the input and output commands of the servo system to obtain the observed values of each state variable of the servo system,and to obtain the expanded state observations of the total disturbance of the system model.By observing and compensating the total disturbance of the system,the original uncertainty model becomes a pure integral link,which is easy to control the system.Finally,a nonlinear control law and model parameter tuning are designed to achieve high-precision control of the system.The system model and the controller model are established on the Maltab/Simulink platform,and the parameters of the servo system are injected into the time-varying disturbance.The auto-disturbance rejection controller based on the expanded state observer realizes the tracking of different instructions.The simulation results verify the correctness and effectiveness of the auto disturbance rejection algorithm in the control application of hydraulic servo system.