Visual servoing for human-robot interaction in the wheelchair-based rehabilitation robot

We provide an introduction to the overall structure of a new wheelchair-based robotic arm system, KARES II, and its human-robot interaction technologies which assist independent life of the elderly and the disabled that have disadvantages in sensory and motor functions of their limbs. First of all, the tasks of a robotic arm are specified. Next, several human-robot interaction technologies are presented to perform the defined tasks in comfortable and safe ways. In addition, the input/output relation of several interaction technologies, such as an eye-mouse, a haptic suit, bio-signal recognition and visual servoing, is described under two essential factors: one is intention reading of the user, and the other is the autonomous capability of the robot. Among those technologies, we concentrate on visual servoing that is a good solution for reducing the burden of a user in a wheelchair with a robotic arm. We mention difficulties of visual servoing in the wheelchair-based robotic arm. It is found that visual servoing using space variant vision has several merits in an eye-in-hand configuration. Specially, a nearby target is handled efficiently through a modified log-polar mapping