Mobile robot predictive trajectory tracking

For a two-wheeled differentially driven mobile robot a trajectory tracking concept is developed. A trajectory is a time-indexed path in the plane, i.e. in the three-dimensional configuration space consisting of position and orientation. Due to the nonholonomic nature of a rolling wheel, the system cannot be stabilized by a continuous time-invariant feedback or by feedback linearization. A novel approach taken in this paper to solve the nonholonomic control problem consists of nonlinear predictive control in conjunction with linear state space control with integration of the control error. Based on a Gauss-Newton algorithm, predicted future position errors are minimized by numerical computation of an optimal sequence of control inputs using prespecified shape functions.