Robust PD control of unmanned land vehicles

For the velocity-following problem of an unmanned land vehicle, the classical PD control law is shown to be robust with respect to highly nonlinear dynamics by properly choosing the control gains. The tracking error system is shown to be uniformly and ultimately bounded. The choices for the gains depend only on the bound of the nonlinear dynamics. Even though the coefficients of the polynomial bounding function are unknown, the robustness PD law can be guaranteed by simply increasing the gains that satisfy certain inequalities. Experiment results are presented to validate the conclusions.<>