Introduction

Traditionally, robotic manipulators are usually bolted on the fixed base. The

workspace of such a fixed base manipulator is a limited volume of the oper-

ation space that can be reached by the end-effector of the manipulator. The

workspace is limited and tasks must be carefully structured so that the ma-

nipulator can reach parts to be assembled. This is typically achieved by means

of conveyor belts or other transporting devices. In the recent several decades,

there has been a great deal of interest towards mobile robots [9], [8], [21], [154].

A mobile robot typically refers to a mobile platform or vehicle, equipped with

computing units and various sensors. The study of mobile robots is mostly

concentrated on a central question: how to move from here to there in a struc-

tured/unstructured environment. It involves many issues such as kinematics,

dynamics, motion planning, navigation, control and coordination.