Integrated design of body and motion improving motion performance of ball throwing robot

Abstract

This paper proposes an integrated robot design method which designs a robot body and a robot motion simultaneously to maximize the robot motion performance. The integrated robot design method is available to design a multi degrees of freedom (DOFs) robot, and it is validated by experiments of a ball throwing robot which has 9 DOFs. The design parameters are the motion pattern and the robot body parameters, and these initial values are optimized by a gradient method to maximize (or minimize) evaluation functions which are given from throwing task conditions. The throwing task conditions contain (i) maximization of ball flyingdistance, (ii) collision avoidance between flying ball and robot hand, (iii)velocity evaluation of motion , (iv) self collision avoidance and (v) limitations of joint angle, angular velocity and torque, etc.. These conditions are utilized as the constraints to obtain the realizable robot motion. A ball throwing motion performed by a human is transformed to a motion pattern of the ball throwing robot, and the robot body parameters are designed simultaneously. Two cases, which contain the improved motion 1 (the robot motion pattern is only designed) and improved motion 2 (the robot motion pattern and the robot body parameters are designed simultaneously), are compared, and these average ball flying distances are 1.33 m and 1.87 m. As a result, the robot motion performance is improved, and effectiveness of the integrated robot design method is demonstrated.

Keywords

• integrated robot design
• body design
• motion design
• ball throwing robot
• human motion