This paper discusses the planning and control problems of a robot manipulator for a class of constrained motions. The task under consideration is to control a robot such that a tool grasped by the end-effector of the robot follows a path on an unknown surface with the aid of a single camera vision system. To accomplish the task, we propose a new planning and control strategy based on multisensor fusion. Three different sensors-joint encoders, a wrist force-Torque sensor and a vision system with a single camera fixed above a workspace-Are employed. We decouple control variables into two sub-spaces: one is for force control and the other for control of constrained motion. We also develop a new scheme by means of sensor fusion to handle the uncertainties in an uncalibrated workspace. The contact surface is assumed to be unknown and the precise position and orientation of the camera with respect to the robot is also unknown.