State of the Art in Hydraulic Switching Control - Components, Systems, Applications

Hydraulic switching control is defined as doing control via fast on-off valves. It currently is driven forward predominantly by fields of application which so far have not been strongholds of hydraulic drive technology. Both, analogy and duality to electrical switching systems exist, the latter prohibiting a direct transfer of many electrical switching principles to hydraulics. The very key component of hydraulic switching control is the fast switching valve. But also very fast check valves for high flow rates are important. Switching causes strong pressure fluctuations. They must be prevented from going beyond accepted areas. Proper attenuation devices or a proper tuning of the system can provide filtering of pulsation. A handful converter principles are known in hydraulics, but definitely many more can be found. They can control pressure, flow rate, or output power. The most challenging problem in the development is a proper design to meet cost, noise, and low pressure ripple requirements yet preserving a good efficiency.