Efficient discrete force control of cylinders may be realised by having multi-chambered cylinders, where the pressure of the chambers are shifted between fixed pressure levels of a secondary controlled system. However, the pressure shifting on a volume where the dynamics of pressure propagation is negligible have been be proven to have an unavoidable minimum loss due to the compressibility of the fluid. This paper investigates the effect of the pressure propagation in the connection and concludes that except more complex shifting schemes are introduced, the minimum loss remains unchanged. The paper analysis however also demonstrates and suggests, that with a clever valve control and shifting scheme, increased efficiency of a shift is obtainable by utilising the pipeline inductance.
Applied Mechanics and Materials, 2012, Vol 233, p. 72-75
Digital Hydraulics; Discrete Displacement; Fluid Power; Hose; Pressure Propagation; PTO; Secondary Controlled System; Wave Energy