Control system design for robot arms playing inside-loop yoyo trick

This study aims to realize a dexterous yoyo trick called “inside-loop” by a robot. In the inside-loop, a yoyo is thrown in an arc from the bottom to the front, passed between the arm and the body, accelerated by quick twisting of the wrist and thrown again to the front. Therefore, the yoyo loops around the hand. To realize this trick, the yoyo model including pulling the yoyo up by taking up the slack string, which is similar to the real behavior, is derived. A reference of a position of the hand is decided by simulations patterned on a human motion, and a controller solves discrete-time optimal control problems every control period. These are verified through numerical simulations. As a result, the inside-loop is realized by the robot.