Abstract: In order to realize the tracking task of heavy or spacio-us bodies, robotic system are often needed due to the limitation of con-trot torque of a single robot.W hen a body is grasped by the end-effectors of several robots, the determination of force/torque of eachrobot is not unique. Furtherrnore conflict phenomenon among robotsAlloy occur and in consequent。may cause instability of the system inthis paper, a new'`Masterr-helper"control strategy is suggested to reme-dy these problems. Simulation of a two-robot system verifies theeffuctiveress of the proposed method.

Key words: rohotic system, tracking task, constrained control, ma- ster-lreiper control strategy