CONTROL OF MECHANICAL SYSTEMS WITH ROLLING CONSTRAINTS - APPLICATION TO DYNAMIC CONTROL OF MOBILE ROBOTS

There are many examples of mechanical systems that require rolling con tacts between two or more rigid bodies. Rolling contacts engender nonh olonomic constraints in an otherwise holonomic system. In this article , we develop a unified approach to the control of mechanical systems s ubject to both holonomic and nonholonomic constraints. We first presen t a state space realization of a constrained system. We then discuss t he input-output linearization and zero dynamics of the system. This ap proach is applied to the dynamic control of mobile robots. Two types o f control algorithms for mobile robots are investigated: trajectory tr acking and path following. In each case, a smooth nonlinear feedback i s obtained to achieve asymptotic input-output stability and Lagrange s tability of the overall system. Simulation results are presented to de monstrate the effectiveness of the control algorithms and to compare t he performance of trajectory-tracking and path-following algorithms.