Modeling and Analysis of a Semiactive Power-Assisted Unit Based on Hydraulic Accumulator

Abstract

The hydraulic accumulator is widely used for storing energy in hydraulic system, but it is a passive device; the flowrate and volume of hydraulic oil adjusted by the accumulator are not well adapted to working-condition changes or payload disturbances. A novel semiactive power-assisted unit (PAU), which is a flow valve-controlled accumulator virtually, is proposed. The flowrate and volume of the accumulator can be regulated by adjusting the spool-opening of the flow valve. The mathematical model of the semiactive PAU is deduced. Then the static characteristic and dynamic characteristic of the PAU are presented. The simulations of the proposed PAU applied in variable-speed electrohydraulic drive system are implemented. The results show the influences of PAU's main parameters on its performance.