Adaptive Robust Control of a Pump Control Hydraulic System

Pump control hydraulic systems have been widely used in industry by the advantages of no throttling loss and overflow loss as well as high power-to-volume ratio. However, the characteristics of high order dynamics, high nonlinearities and disturbances make the accurate position control of those systems very challenging. And to implement the controllers easily, some dynamics such as servo motor loop are usually ignored in most of existing methods, which may lead to the limitation of closed-loop bandwidth and disturbance rejection ability. In this paper, adaptive robust control (ARC) algorithm is utilized in a pump control electro-hydrualic system. The ARC guarantees the stability and high performance in the presence of model uncertainties and nonlinear disturbances. For the high-order of the hydraulic system, a modified three-step backstepping method is constructed which is covering the whole electro-hydraulic system. The servo motor-pump dynamics is taken into considered in the three-step adaptive backstepping controller design. Theoretical control performance based on Lyapunov functions and the simulation results proved that the control strategy this paper proposed achieved high performance in spite of the nonlinearities and uncertainties.