Nonlinear tracking control for nonholonomic mobile robots with input constraints: an experimental study

This paper presents experimental results of nonlinear trajectory tracking controllers for nonholonomic mobile robots with fixed-wing UAV-like input constraints. Programmed to emulate an unmanned air vehicle flying at constant altitude, a nonholonomic mobile robot is assigned to follow a desired trajectory to transition through a sequence of targets in the presence of static and dynamic threats. Two velocity controllers with input constraints are proposed for tracking control. Hardware results using these two velocity controllers are compared to simulation results of dynamic controllers based on nonsmooth backstepping to demonstrate the effectiveness of our approach.