Simultaneous control of trajectory tracking and coordinated allocation of rocker-bogie planetary rovers

摘要

The tracking control and the coordinated allocation control of the planetary rover on soft uneven terrain are rarely addressed at the same time. This paper presents a simultaneous control method of trajectory tracking and coordinated allocation to track the desired trajectory and keep little internal forces. The proposed method consists of two parts: the trajectory tracking controller based on the kinematic model and the coordinated allocation controller based on the dynamic model. In other words, both motion information and force information are used. By rewritten the kinematic model, an improved linear active disturbances rejection control (ILADRC) controller is designed to decrease the longitudinal and lateral tracking errors caused by slipping and skidding. Then by employing the H_2/H_∞ controller based on the dynamic model, the rover inputs are obtained, and by solving the QP problem using the active-set method, the rover inputs are allocated to each wheel to decrease the internal forces. Based on the wheel-terrain mechanics, the force tracking controller in speed mode is designed using the ILADRC. The final control inputs are the weighted sum of these two angular velocities inputs. Experimental results demonstrate that the controller can decrease the internal forces between wheels on the same side by at least 60%, yet with satisfactory tracking performance.