Multi-objective combined adaptive control of wheel-legged composite all-terrain chassis for hilly areas

The all-terrain chassis of the wheel-legged composite structure exhibits significant adaptability to complex terrains. However, the high degree of operational freedom complicates the control of the overall attitude, resulting in an increased risk of instability during the attitude adjustment process. Additionally, environmental sensing sensors frequently prove inadequate for practical engineering applications. To address these challenges—specifically, enhancing trafficability and stability while minimizing sensor dependency—this paper introduces a novel multi-objective adaptive control method designed for unknown terrains. The primary contribution of this research is a gravity-compensated proportional-derivative (PD) control strategy based on a virtual controlled object. This approach relies solely on body attitude and outrigger motion data obtained from onboard inertial measurement units (IMUs) and angle sensors, which do not interact with the environment, to track a desired virtual height. The control output force is directed toward the motion of the hydraulic cylinder and is integrated with expected ground clearance control to achieve adaptive stabilization of the entire machine. Importantly, this method capitalizes on the numerical characteristics of the hydraulic cylinder’s driving force during ground contact, allowing for adaptation without the need for direct terrain sensing. Simulation experiments conducted on unilateral slopes and continuous undulating terrains validate the feasibility of the proposed control strategy, demonstrating effective maintenance of attitude and wheel-ground contact.