Design and experiment of an improved dual-accumulator hydraulic fully active suspension system

This paper presents a dual-accumulator hydraulic active suspension (DAHAS) system capable of switching between active and semi-active modes. Unlike conventional designs, the proposed actuator integrates a motor-pump unit (MPU) for low-frequency vibration control (below 5 Hz) and a dual-valve continuous damping control (CDC) damper for higher-frequency disturbances (15–20 Hz and above). The dual-valve configuration enables independent regulation of compression and rebound strokes, extending the controllable damping range. A seven-degree-of-freedom vehicle model with random road excitation is established, and the motion-mode energy method is used to identify the dominant vibration mode. A coordination control framework is developed, where a sliding mode controller governs the active mode, while a skyhook control strategy handles the semi-active mode. Simulation and experimental results demonstrate that the proposed system significantly improves ride comfort and handling stability across a broad frequency spectrum while reducing energy consumption by selectively activating the MPU.