Throwing motion control experiment utilizing 2-link arm passive joint

This paper describes the throwing motion control experiment utilizing a 2 link arm with a passive joint. In throwing, dexterous actions can be seen. Dexterous throwing uses energy transfer from a trunk of the body to a hand and a physical constraint at the elbow joint. However, human throwing is very difficult to analyze all features, because throwing motion performs in three dimensions. Therefore, under-actuated 2 link model is applied in this paper. Proposed model has a spring joint which is represented as an armpsilas stiffness and a constraint at elbow joint. For this model, the control method based on output zeroing which specifies the path of the ball at the end-effector is proposed. By developing an experimental equipment and carrying out experiments of throwing motion control, the effectiveness of the proposed control method is verified.