Tracking control of a mobile manipulator with fuzzy PD controller

In this paper, we suggest a fuzzy PD controller for a dynamic model of nonholonomic mobile manipulator in order to treat the trajectory tracking control and to eliminate the effect of external force on the end-effector. Firstly, the dynamic model of the mobile robot in motion space is detailed. Secondly, a fuzzy PD controller is conceived to adjust the parameters of the PD controller online depending on the actual state of the dynamic system. In particular, the mobile robot can follow every path such as a straight line or a sinusoid. Simulation results are given to demonstrate the effectiveness of the proposed controller and to illustrate the coordination of two subsystems in performing the desired trajectory.

1. Introduction

A mobile manipulator is composed of a mobile platform carrying a standard robotic manipulator. Such robotic system merges the skills of the manipulator with the increased workspace capabilities of the base, and thus is particularly suited for field and service robotic applications ([1], [2]). The nonholonomic kinematic constraints provoked by the wheeled configuration, the complex structure and the coupled dynamics between the mobile platform and the manipulator are among the features that make the control of mobile manipulator very challenging.