Experimentally validated models for switching energy of low pressure drop digital valves for lightweight portable hydraulic robots

The most critical factors for a switching valve in a lightweight, portable hydraulic systems are low pressure drop, low power consumption, fast response time, and small size and weight. In this paper, experimentally validated models are proposed for switching energy required by two valve architectures with minimum pressure drop (ball and butterfly valves). The orifice in a hydraulic valve creates a pressure drop across the valve that needs to be minimized especially for low-pressure passive applications. The ideal switching valve for a hydraulic device is one with an opening diameter that is the same as the hose diameter. Several valve architectures with low pressure drop can be motorized to be used as a digital valve. The valve operation mechanism determines the power consumption of the valve. In this paper, the energy to switch state was modeled for two rotary valve types: butterfly and ball. The model was being used to find the best valve configuration for low-pressure digital hydraulics. The model was validated through experiments on a low-pressure ball valve, a high-pressure ball valve, and a low-pressure butterfly valve. The butterfly valve has the lowest switching energy for the same geometry; however, this valve has a small pressure drop due to the presence of the disc in the open position. We conclude that either ball or butterfly valves are suitable for low-pressure, small-scale hydraulic applications.