Pressure-Velocity Compound Control Strategy of Hydraulic System

Taking the valve control cylinder system controlled by proportional relief valve and proportional speedregulating valve as the research object, this paper established a dynamics model of hydraulic system. The friction force of propulsion hydraulic cylinder was compensated based on LuGre model. The bristly observer was established to estimate the motion characteristics of the spool and the stability of the observer was proved by Lyapunov first method. The uncertainty of hydraulic system was integrated with external load interference, and the adaptive rate was estimated. Based on the inverse integral adaptive control algorithm, a pressure-velocity compound control strategy was proposed and the stability of the control strategy was verified. Based on the hydraulic cylinder speed control, the pressure error was introduced into the speed expectation to realize the pressure-flow compound control of valve control cylinder system. The co-simulation platform of the valve-controlled cylinder system was established in AMESim and Matlab, and the speed regulation, sudden load and load disturbance of the valve-controlled cylinder system were simulated and analyzed under different error proportions. The simulation results show that the pressure-velocity composite controller has good control performance under the conditions of speed regulation, sudden load and load disturbance of the valve control cylinder system. The overflow control of proportional relief valve effectively reduces the fluctuation and overshoot of system pressure. Overchanging the proportion of pressure error can effectively change the distribution of pressure and velocity error when the formation changes abruptly. In practical engineering, the distribution of compound control error can be carried out by changing the proportion of pressure error according to the need.