Comparative study of tracking control for a mobile manipulator: Nonholonomic and dynamic cases

This paper gives an in-depth treatment of the modeling and control of a mob ile manipulator which consists of a robotic manipulator mounted upon a mobi le robot. By neglecting slip of the platform's tires, nonholonomic constrai nts are introduced into the equations of motion. By considering wheel slip, the assumption of nonholonomic motion is violated. Nonholonomic and dynami c models of a mobile manipulator are developed and compared using the Lagra nge -d'Alembert formulation and the Newton-Euler method, respectively. The dynamic model which considers wheel slip incorporates a nonlinear tire fric tion model. The tracking problem is investigated by using input-output line arization for the nonholonomic model. For the dynamic model, a robust contr ol method based on a matching condition is developed to eliminate the harmf ul effects of wheel slip, which acts as a disturbance to the system. Then, the effect of wheel slip on the tracking of commanded motion is identified via simulation. The effectiveness of the proposed control algorithm is demo nstrated through computer simulation.