This paper deals with cooperative transportation by a group of car like mobile robots regrasping an object. The authors propose the following approach: (1)designing a robot hand system, end-effector with compliant passive joint set up with offset: (2)robot motion planning by optimizing under constraints of available torque limitation that can be applied to an object. This end-effector enables us to avoid complications with motion planning because of non-holonomic characteristics. It also enables cooperation among robots that have errors in positioning. And torque limitation is considered in order to prevent slipping between the wheels and a floor. The effectiveness of the motion planning algorithm has been verified by transport simulations. Experiment shows that cooperative transportation can be realized.
