Decoupling Compensation for Damping Improvement of the Electrohydraulic Control System With Multiple Actuators

This paper proposes a decoupling compensation method for damping improvement of the electrohydraulic control system with multiple actuators. The low damping property of hydraulic systems has been a remarkably troublesome issue for a few decades. Previously, this issue with one actuator has been addressed effectively by state feedback and signal compensation, e.g., dynamic pressure feedback. However, the poor damping with multiple actuators is still intractable and pendent due to the complex coupling effect of different loads. A decoupling compensator based on pump/valve combined control is proposed for a typical electrohydraulic system with multiple actuators for mobile machinery. Using decoupling control of different load branches, the coupling hydraulic circuit with multiple cylinders is transformed into multiple separate single-cylinder circuits with dynamic compensation. The dynamic characteristics of different actuators are then improved synchronously without mutual interference, while the steady performance remains the same without loss of controllability. Compound motion tests on a 2-ton hydraulic excavator were carried out. The results showed that the proposed compensator reduced velocity and pressure oscillations under different working conditions, so the dynamic performance is improved for the multiactuator system.