Robust Optimal Tracking Control for Wheel Mobile Robot: An Actor–Critic Approach

The robust optimal trajectory tracking control problem for a non-holonomic wheel mobile robot usually remains a difficult problem due to the nonlinearity and non-holonomic constraint of this robot. Moreover, the presence of external disturbances acting on the system may lead to degraded control performance or even instability. To overcome these challenges, a hierarchical control structure, including kinematic and dynamic control loops, is developed to address the non-holonomic constraints of the robot. In the dynamic control loop, a nonlinear disturbance observer is proposed to estimate and compensate for disturbances. Furthermore, based on the actor-critic control strategy, an optimal controller is developed, which achieves the optimal trajectory tracking. redBy this way, the non-holonomic wheel mobile robot equipped with the proposed controller not only achieve the optimal trajectory tracking but also maintains robustness against disturbances. A simulation result built in the MATLAB software is conducted to confirm the superior performance of the proposed method. Compared to PD control approach, the proposed control approach achieves superior performance indices.