Manipulation model of thread-rotor object by a robotic hand for high-speed visual feedback control

Robotic manipulation of a flexible object is a challenging task due to the complexity in modeling and control. Moreover, at high speed, manipulation becomes a more difficult task. Using high-speed sensors and actuators can make such manipulation more easily achievable, thereby increasing a robot´s usefulness. In this paper, we use a button spinner as an example. The objective is to observe and control the twisting of flexible threads at high speed. Our contributions are as follows: First, we develop an extended twisting model for a pair of threads. Second, we propose a practical method to measure the twist of the threads via angular position of a rotor. This method works even when the thread is being twisted at very high speed, more than sixteen thousands revolutions per minute, theoretically. Finally, we show the validity of our model using simulation. In our method, control of the button spinner is considered to be performed without any force feedback, only with visual feedback.