Energy-saving control for electro-hydraulic systems under time-varying negative loads

Abstract

In a hydraulic system, employment of counterbalance valve introduces sizable energy consumption. In addition, a pressure-feedback control architecture with inflexible parameters causes instability under time-varying negative loads. As an alternative, an adjustable meter-out orifice was adopted, and a stable controller was proposed in this study. By combining inlet pressure and velocity, the concept of a flow rate follower was developed. Mathematical analysis of dynamic model illustrated that both the inlet pressure and velocity converged to a range related to the flow rate follower bounds. Feedback linearization with robust control was utilized such that flow rate follower converged in the presence of parametric uncertainties; meanwhile, a high-gain load observer was constructed for disturbance compensation. The effectiveness of the controller was verified by experiments and its performance discussed. As a result, the inlet pressure was held near a specified low value, thus significantly reducing energy consumption. Also, the velocity matched the supply flow rate, and the oscillations were acceptable in applications.

Modeling and control of a high-quality electro-hydraulic actuator driven via an induction motor under intelligent indirect vector control

“…Based on research on a system that included counterbalance valves with time-varying negative loads and a variable meterout flow control valve, Jin and Wang [33] produced a stable controller. The controller modifies the actuator's velocity and the load state to change the pump displacement.…”

Modeling and Control of a High-Quality Electro-hydraulic Actuator Driven by an Induction Motor under Intelligent Indirect Vector Control

“…Based on research on a system that included counterbalance valves with time-varying negative loads and a variable meter-out flow control valve, Jin and Wang [35] produced a stable controller. The controller modifies the actuator's velocity and the load state to change the pump displacement.…”

Adaptive Backstepping Sliding Mode Control for the Vertical Launching Barrel-Cover of the Underwater Missile

“…The vertical launching barrel-cover of the underwater missile adopts electro-hydraulic servo system to drive the launching barrel-cover [4]. However, the symmetry device has the characteristics of parameter uncertainty [5], load time-varying [6], strong nonlinearity of motion [7,8], and coupling [9,10] during the submarine movement [11]. Therefore, the study of the nonlinear adaptive anti-interference control method is of considerable significance to the improvement of the performance of the barrel-cover system [12].…”