Abstract –In this paper, a mobile manipulator consisting of four degrees of freedom
(4-DOF) robotic manipulator mounted at the top of a mobile platform (front point) of a
mobile robot with four differential drive wheels is presented. A mobile manipulator
combines the dexterous manipulator capability offered by fixed-based manipulators and
the mobility offered by the mobile robot. The work involves the modeling of mobile
manipulator robot and using the partial feedback linearization approach. The central
idea is to algebraically transform nonlinear systems dynamics into partially linear form,
so that linear control techniques can be applied to control on the wheel mobile
manipulator robot in order to track any trajectory such as an ellipse, circle….etc,
without violating the non holonomic constraints. However, and in order to consider the
uncertainty in system parameters and the effects of the external disturbances a nonlinear
PID controller is proposed in this work. The results demonstrate a good ability of the
designed nonlinear PID controller in regulating the mobile robot to track the desired
path in the presence of the external disturbances and the uncertainty in system