Rotation control of polygonal prism by multi-legged robot

Rotation is one of efficient transportation methods for big or heavy object. For implementing the rolling operation to the small and light weight robot, it is necessary to consider the movable range of the robot, balance, actuator power and friction control. In this paper, we propose a new method of forward and backward rolling manipulation by using whole body motion for multi-legged robot. To control the balance, the weight shift control considering the Imaginary Zero Moment Point (IZMP) of the object is implemented. When the IZMP is beside the support polygon of the object, the object has rotational force. The rotational force is controlled by the force from the robot, and it can be manipulated by controlling the robot's CoM position and the internal force generated by joint actuators. The internal force can adjust the rotational force but it should be generated considering the friction forces between the object and the floor etc. We analyze available internal force with friction by kinematic solution, and it is implemented to the small multi-legged robot by using position and torque control. The effectiveness is confirmed through experiments.