1、Introduction
When a person writes some things on a blackboard, he/she positions his/her arm in a comfortable writing configuration by moving his/her body rather than reaching out the arm. The same situation happens in many cases such as people transporting a heavy object cooperatively. Therefore, when a mobile manipulator performs a manipulation task, it is desirable to bring the manipulator into certain preferred configurations by appropriately planning the motion of the mobile platform.
If the trajectory of the manipulator end point in a fixed coordinate system(world coordinate system) is known a priori, then the motion of the mobile platform can be planned accordingly. If the motion of the manipulator end point is unknown a priori, e.g., driven by a visual sensor or guided by a human operator, the path planning has to be made locally and in real time rather than globally and off line.
