High Precision Energy Saving Motion Control of Hydraulic Cylinder Based on Integration of Valves and Pump

The independent metering approach makes the two chamber pressure states of the hydraulic actuator completely controllable, which offers the opportunity for energy conservation by reducing the working pressure. However, there still remains a great deal of throttling losses since the entire flow rate is throttling controlled with the valves. In order to avoid throttling losses, the direct pump controlled system might be an option, but the relatively slow dynamic response restricts its application in occasions with response and precision demands. To realize further energy conservation and simultaneous high precision tracking performance, this paper proposes a brand new hardware configuration which integrates the direct pump control, independent metering, and energy reuse methods and takes advantages of their respective strengths. The adaptive robust control approach is applied to deal with the nonlinear control problems. Comparative simulations are done with the focuses on energy consumption and tracking performance.