Development of tele-operation system for a crane without overshoot in positioning

A tele-operation system for a crane is developed. The crane consists of a small actuator and a large actuator in x and y direction respectively. The large actuators are controlled by input signals from an operator and the small actuators are used as a regulator and feedback controlled by a wire angle sensor. Since a motion of the suspended object can be approximated as a second order system, overshoots of the object inevitably happen at the moment when the operator give a stop command to the system. To avoid this overshoots, a novel user interface is developed where operators indicate via points or target point of the object on a monitor screen from the camera imaging the scene below the crane. The system interpolates the via points by using four order functions and give the velocity commands to the crane until the inputs of the via points are stopped. The final point is regarded as the target point. From experimental results, the effectiveness of the developed control system and its control algorithm is verified.