Output adaptive control of a skid steering autonomous vehicle

This work presents the design as well as the evaluation of an output adaptive controller which must induce the stabilization of the tracking error for a class of skid steered autonomous vehicle (SSAV). The control design includes a nonlinear transformation (diffeomorphism) using a simplified SSAV mathematical model. This diffeomorphism justifies the transformation of the control problem in the original coordinates to a suitable chain of integrator system (third-order). In this study, the available measurements are the position and orientation of the SSAV. The aforementioned condition, encourages the implementation of a modified super twisting algorithm (STA) which is applied as a recursive differentiator which may estimate the velocity and acceleration of the SSAV efficiently. Based on the estimated states, an adaptive controller provides the asymptotic stability of the tracking trajectories for the SSAV. Numerical evaluation comparing the proposed adaptive controller with a state feedback controller confirmed the design of the suggested control structure.