Energy-saving adaptive robust motion control of single-rod hydraulic cylinders with programmable valves

This paper studies the energy-saving adaptive robust motion control of a single-rod hydraulic cylinder through the use of programmable valves. The programmable valve used in this study is a unique combination of five proportional cartridge valves connected in such a way that the meter-in and meter-out flows can be independently controlled by four of the valves as well as a true cross port flow controlled by the fifth valve. The programmable valve decouples the meter-in and meter-out flows which in turn allows tremendous control flexibility. Although at the expense of controller complexity, if well utilized, the added control flexibility can be used to significantly reduce the fluid power energy usage in a number of motion and loading conditions to meet society's need for energy conservation without sacrificing achievable motion control accuracy. Such a coordinated control solution is provided and is shown to be effective through both simulation and experimental results in the likely operating conditions of a typical industrial backhoe loader arm.