Dynamic impact shot control with VSC servo

A control method for dynamic shot is proposed. A goal is to realize a juggling motion with the shot of a hanging ball by a club mounted on a motor. To succeed in juggling stably, it is necessary to make the club-head reach to the target position while keeping the specified velocity just on a fixed time. The needed velocity for hitting the ball and the rest time by collision are obtained by the energy-based calculation. By using these information a smooth reference trajectory for the motor-drive is computed in real time. To make the motor to trace the reference path exactly, we adopt a variable structure control (VSC) approach. VSC is well known as one of high robust control techniques, but it tends to chatter on real systems. To avoid this problem, we propose new type of VSC. The input law is obtained with a form of integral of the sign function of a switching sliding mode, therefore there is less chattering than the conventional VSC method. The effectiveness of the strategy of juggling using the proposed VSC is verified through a simulation and experiment