Nonlinear supply pressure control for a variable displacement axial piston pump

Abstract

For many electro-hydraulic pump-controlled systems, supply pressure control of the hydraulic pump is of great importance. However, the control performance is significantly affected by unknown time-varying load flow requirements. To improve the supply pressure tracking performance in the presence of unknown time-varying load flow disturbances, a nonlinear controller is designed based on the control-oriented mathematical model presented in this article. First, a disturbance observer is used to estimate the unknown time-varying load flow; a nonlinear feedforward controller is then derived using the differential flatness property of the system based on the estimated load flow; in addition, a feedback controller is implemented to stabilize the system. Sliding mode control is also used to compensate for load flow estimation error. The stability of the whole system is proved using Lyapunov theory. Experimental results demonstrate that the proposed control strategy has good supply pressure tracking performance.

Investigation into the Effects of the Variable Displacement Mechanism on Swash Plate Oscillation in High-Speed Piston Pumps

“…Figure 6a shows the comparison of the improved model results and the common model results at the flow rate 1.5 L/min. The common model is based on previous research on the piston pump system [20][21][22][23][24][25][26][27]. There are significant differences between the two results.…”

“…They achieved adjustable swash plate vibration reduction at the desired frequency by the active vibration control. In the studies on the electro-hydraulically controlled variable displacement pumps [21][22][23][24], the swash plate angle of the piston pump was measured and controlled, but no obvious oscillatory behavior of the swash plate angle was noticed. The displacement angle was also measured with a Hall-effect sensor in a hardware-in-the-loop simulation test rig by Larsson et al; he used a pole placement approach combined with a lead-compensator controller architecture to control the swash plate angle [25,26].…”

Driving pulsation analysis of electro-hydraulic robot

“…Then the internal mechanical structure of the plunger variable displacement pump is further optimized Sa et al, 2014a, 2015b). (Wei J, et al, 2015) designed a nonlinear controller based on the control-oriented mathematical model, and the stability of the whole system is proved using Lyapunov theory. In addition, a reducing the output flow pulsation rate method by optimizing the valve plate structure of the plunger variable displacement pump was proposed in 2017 (Wu et al, 2017), and the optimal simulation results were obtained by using AMESIM software: when the output pressure of the constant pressure variable pump was 200 bar, 300 bar and 400 bar, the output flow pulsation rate decreased by 37.05%, 38.54% and 41.04%, respectively.…”

Research on Control Methods for the Pressure Continuous Regulation Electrohydraulic Proportional Axial Piston Pump of an Aircraft Hydraulic System

“…Koivumaki [21] proposed for the first time not using any linearization or order reduction, and an adaptive and model-based discharge pressure control design for the variable displacement axial piston pumps (VDAPPs), whose dynamical behaviors are highly nonlinear and described by a fourth-order differential equation. A nonlinear supply pressure controller for a variable displacement axial piston pump was proposed in reference [22]. A load flow disturbance observer was proposed to deal with unknown and time-varying load flow.…”