Active Disturbance Rejection Decoupling Control for Independent-Metering Electro-Hydraulic System With Online Compensation Information

Aiming at the problems of complex operating conditions, large load disturbance, strong coupling of pressure and position control subsystems, and time-varying parameters of independent metering electro-hydraulic servo system (IMEHSS), an active disturbance rejection decoupling (ADRC) control method with online compensation information is proposed in this paper. In this study, the internal coupling of subsystems is treated as the part of total disturbances, and decoupling control is realized by estimating and compensating the total disturbance through extended state observer. In position control subsystem, the cylinder dynamic changes caused by the inlet chamber flow rate of cylinder and the deviation of the nominal calculated flow rate from actual calculated flow rate are calculated in real time. And these calculated values are compensated to the controller as online information to improve the control accuracy and the disturbance rejection ability of position control. By calculating the cylinder velocity in real time to obtain the effect of cylinder speed on the change of return chamber pressure and compensating it into the controller to improve the return chamber pressure control accuracy. The online information compensation method presented in this paper reduces the amount of total disturbance and thus reduces the burden of extended state observer. At the same time, this method can realize the proportional relationship between the regulation parameters and control signals in the passive pressure control subsystem, which simplifies the tuning process of parameters. Finally, to verify the effectiveness and rationality of the method, simulations and experiments are carried out.