Research on two kinds of servo control elements effect on highly integrated valve-controlled cylinder

The joint drive of quadruped robot, the highly integrated valve-controlled cylinder (HIVC), whose control performance could effect on the whole machine of the robot directly. In this paper, based on the structure principles of flow servo valve and pressure-flow servo valve, the mathematical models of above two kinds of servo valve are established to analyze their dynamical performance respectively. To ensure the accuracy of the analysis results, the flow gain of above two kinds of servo valve are unified, then using them for force close loop control of HIVC on the performance test platform of HIVC, the effects of step force and sinusoidal force on the force control performance of HIVC with different forward channel gain are tested, moreover, the force control performance of HIVC under different frequency position disturbance are tested. The test results indicates both flow servo valve and pressure-flow servo valve can realize force close loop control of HIVC, but by comparison, due to the load pressure which is existed in pressure-flow servo valve power level spool equilibrium process, the output flow decrease sharply with load force increasing, which can lead the load force control performance of HIVC which consists of pressure-flow servo valve is inferior to those which consists of flow servo valve. All the research conclusions can provide a theoretical and experimental foundation for the selection of servo control element of HIVC.