A robust trajectory tracking controller for constrained and perturbed unicycle mobile robots

This paper contributes to the design of a robust control strategy for the trajectory tracking problem in constrained and perturbed unicycle mobile robots. The proposed robust control strategy is composed of two controllers: a linear and a nonlinear. The linear control design is based on the barrier Lyapunov function and the attractive ellipsoid method, and it considers the input saturation, the state constraints, and some parameter uncertainties. On the other hand, the nonlinear part is based on an integral sliding-mode control approach that deals with the effect of some matched disturbances and the input saturation constraints. The proposed scheme guarantees asymptotic convergence to zero of the tracking error coping with the system constraints and disturbances. Simulation results are presented in order to show the advantage of the proposed algorithm with respect to an MPC-based robust controller. Some experimental results, using the QBot2 unicycle mobile robot, validate the effectiveness of the proposed robust control strategy.