Force transmission control in multilateral system for teletraining

Recently, skill preservation of an expert has been a serious problem of the medical or production fields. It is difficult to acquire a human motion including touching motion by the conventional visual-based system. A touching motion is inherently bilateral, since an action is always accompanied by a reaction. A bilateral force feedback control is necessary to acquire the human's skill. This paper proposes a haptic teletraining system by multilateral force feedback control. Since the multilateral control transmits haptic information among three or more remote systems, it is possible to train remote trainee by one skilled trainer simultaneously. In the proposed haptic teletraining system, each local system consists of a master-slave system. Since a touching motion is subject to the "law of action and reaction", it is possible to decompose the force information into action force and reaction force by using the bilateral control. Thus the skilled motion by a trainer is acquired and saved as a digital database integrated with his haptic information. The proposed system is applied to one-trainer/two-trainee system. As a result, a motion including contact with the environment is transmitted and trained with vivid force feedback. The experimental results show viability of the proposed method.