Robot body design including degrees of freedom and link parameters maximizing ball throwing performance

This paper proposes a particular case of a robot body design method which determines a degrees of freedom (DOFs) number and link parameters to maximize a target task performance. The DOFs number is an essential point to be considered in the robot body design problem. In this paper, the target task is to make a long throw, and multi DOFs ball throwing robot is designed. Design parameters are the robot body parameters and its motion pattern, and they are designed to maximize ball flying distance under long throw task conditions. To define the link lengths and the robot DOFs number as design parameters, it is assumed that intermediate links of the robot have identical actuators, and these link parameters are defined as functions of link lengths. These links are chained to construct the whole link system. Because of this assumption, the motion equation, which is utilized in the task conditions, is determined by the given robot DOFs number and link lengths. The proposed method was applied to the ball throwing robot model, and its body parameters and motion pattern were designed in the proposed calculation algorithm. As a result, 5 DOFs robot and its throwing motion were obtained, and the ball flying distance was maximized. The ball flying distance was changed along with the DOFs number, and the effectiveness of the proposed design method was demonstrated.