Practical adaptive robust tracking control of the dual-valve parallel electro-hydraulic servo system with reduced-order model

Abstract

To meet the increasing demand for trajectory tracking accuracy and high-efficiency requirements in modern mobile machinery, this paper proposes a practical adaptive robust control method based on the dual-valve parallel electro-hydraulic servo system. Existing tracking control strategies for such servo systems rely on a backstepping method and assume that full states are known, which is stringent in practice. To cope with the problem, we reduce the mathematical model order of the studied system using singular perturbation theory in this paper, and only the position feedback is required for the control implementation. Then, to achieve high accuracy tracking control, a direct adaptive robust control scheme combing with a dynamic flow allocation layer is adopted to synthesize the controller. With this method, parameter uncertainties and load disturbance are rejected, and valve characteristics are considered in the dynamic flow allocation layer to solve the flow redundancy problem, respectively. Convergence of the simplified system tracking results is proved theoretically. Extensive co-simulations and experimental tests are carried out to illustrate the effectiveness of the proposed strategy, both tracking precision and flow distribution can be achieved efficiently by simple parameter adjustments in the field.

Terminal Sliding Mode Force Control Based on Modified Fast Double-Power Reaching Law for Aerospace Electro-Hydraulic Load Simulator of Large Loads

“…By manipulating the connection stiffness [6] and arm length [7] between the loading mechanism and the steering gear system, the connection mechanism is optimized in conjunction with a control algorithm, thus effectively mitigating the surplus force. The dual-valve parallel control that consists of the large flow valve and small servo valve is designed to achieve a high control accuracy in electro-hydraulic servo systems in [8]. To reduce the extra torque generated by the forced flow, substitution of the pressure servo valve for the flow servo valve is adopted in the passive force control system, to form a pressure closed-loop control for obtaining high-precision torque tracking in [9].…”