Nonlinear controller design for a mobile manipulator trajectory tracking

Abstract EN

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 parameters.