Experimental validation of an optimum design method for a ball throwing robot considering degrees of freedom, link parameters, and motion pattern

Abstract

This paper considers a particular case of a robot body design method which determines degrees of freedom (DOFs) number and link parameters to maximize a target task performance, and feasibility of this design method is validated by several experiments. In this paper, the target task is to throw a ball a long distance, and a multi DOFs ball throwing robot is designed and manufactured for the experimental validations. Design parameters are the robot body parameters and its motion pattern, and they are designed to maximize ball reaching distance under long throw task conditions. To define the link lengths and the robot DOFs number as design parameters, it is assumed that robot links have identical actuators, and these link parameters are defined as functions of link lengths. This design method is applied to the manufactured ball throwing robot, and its body parameters and motion pattern are designed. The ball reaching distance is changed along with the DOFs number, and as a result, 5 DOFs robot body and its throwing motion are obtained, and the ball reaching distance is maximized. Finally, the ball throwing experiments of the designed 2 DOFs and 5 DOFs robots are executed in each 8 trial. Average values of the ball reaching distance are close to the calculation results, therefore, the feasibility of the calculation results is demonstrated.

Keywords

• robot body design
• robot motion design
• ball throwing task
• joint degrees of freedom number
• link parameters