Energy-Saving Control of Single-Rod Hydraulic Cylinders with Programmable Valves and Improved Working Mode Selection

This paper studies the energy-saving adaptive robust precision motion control of a single-rod hydraulic cylinder through the use of programmable valves. The programmable valves 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 valves decouple the meter-in and meter-out flows providing tremendous flexibility to control the cylinder motion while decreasing the energy usage by utilizing the potential and kinetic energy of the load. This paper investigates the different working conditions of the programmable valves and proposes a simple yet effective way to use the programmable valves based on the desired states and current states.