Kinematics, dynamics and control of wheeled mobile robots

The controllability of nonholonomic robot systems is proved for six common wheel and axle configurations that possess two or three degrees of freedom. After the kinematics and dynamics were modeled using the synchro-drive vehicle as an example, it was proved that continuous feedback stabilization of the vehicle to an equilibrium point is impossible. The dynamic model so developed is also used to prove that simple controllers are sufficient to guarantee stability for the drive- and steering-angle components of synchro-drive vehicles. Although the underlying control systems are stable, the experimental results demonstrated that potential-field navigation can lead robot trajectories to an unexpected invariant set. The results reported can easily be extended to the modeling and control of other mobile robot systems