Prescribed-Time Adaptive Robust Force Control of a Pump-Controlled Active Suspension Actuator for Rapid Pressure Build-Up

To address insufficient effective flow, delayed force response, and degraded tracking accuracy of pump-controlled active hydraulic suspension actuators during rapid pressure build-up and frequent reversal, a prescribed-time adaptive robust force control method based on a fixed-time flow-deficit observer is proposed. Pump leakage, oil compression, and reversal pressure reconstruction are uniformly represented as an equivalent flow deficit, which is estimated online and compensated by feedforward. By combining the prescribed-time performance function, adaptive law, and continuous robust term, the method constrains the force error and suppresses uncertainty. Stability analysis shows that all closed-loop signals are uniformly ultimately bounded and that the force error enters the specified boundary within the prescribed time. Experimental results demonstrate that the proposed method improves rapid pressure build-up and dynamic force-tracking accuracy under step and sinusoidal commands.