A high-speed method of detecting contact-state transitions and its implementation in a task-coordinate manipulation system

We have developed a highly reliable method of detecting contact-state transitions in real time. In the detection algorithm, feature variables, which fluctuate abruptly when a contact state transition occurs, are selected. The differential of the feature trajectory is monitored to distinguish the transition region from the stable region. To confirm that a state transition has actually occurred in the region, the duration of the region is measured. With this method, a contact-state transition can be detected with a 40-msec delay. We also have developed an experimental manipulation system, in which motion execution management and motion monitoring and execution modules operate independently. Using transputers and a six-degree-of-freedom direct-drive manipulator, a square-peg insertion task is carried out to evaluate the effectiveness of the detection method in an actual environment. The experimental results show that contact-state transitions can be accurately detected and that motion commands can be quickly switched by using the detected transition information