Internal force control for rolling operation of polygonal prism

Abstract

Rotation is one of efficient transportation method for big or heavy object. For implementing the rolling operation to the small and light weight robot, the friction control is necessary considering its movable range, balance and actuator power. In this paper, we propose a new rolling manipulation by using whole body motion for multi-legged robot. The weight shift control is implemented considering the Imaginary Zero Moment Point (IZMP) of the object to control the balance. 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. The internal force can adjust the rotational force but it should consider 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 torque control. The effectiveness is confirmed through experiments.