Study on casting manipulation (midair control of gripper by impulsive force)

We have been developing a casting manipulator which includes a flexible string in the link mechanism to enlarge the work space of the manipulator. During casting manipulation, a gripper is thrown to its target by releasing the string at a suitable time after generating enough motion by swinging. In this paper we deal with the midair control of the gripper after throwing it. First, we consider the factors which disturb the trajectory of the gripper, and point out the necessity of modifying the trajectory after throwing the gripper. Then we propose the utilization of an impulsive force applied to the gripper in the air through the string by restricting the motion of the string. Investigating the impulsive force generation through experiments, we confirmed the effectiveness of the method which was evaluated by comparing the results of numerical simulations with those of our experiments using the experimental casting manipulator hardware