Throwing motion control based on output zeroing utilizing 2-link underactuated arm

This paper deals with motion control of throwing generated by dexterous action. Dexterous actions can be seen in many sports. In baseball pitching, dexterous throwing seems to use energy transfer and a physical constraint at the elbow joint. To implement the dexterous throwing, two types of two-link underactuated manipulator are presented. One model has a spring at 2nd joint which represents an arm´s stiffness and a constraint at elbow joint, another model has a physical absolute constraint at elbow joint. For these models, throwing motion control method based on output zeroing which specifies the path of the ball held by an end-effector is proposed. The proposed control strategy realizes the energy efficient motion for throwing to the desired direction. Simulation and experimental results show the effectiveness of the proposed control method.