人工現実感による上肢訓練および筋力計測システムの開発

抄録

This paper reports on a virtual training environment developed using virtual reality technology with force and visual image feedback capability. In our system: (1) A light and safe force-display implemented using a pneumatic rubber actuator is available. It has a wide range of motion and large driving force comparable to those of human joints and muscle. (2) The trainee's muscle characteristics can be measured. (3) The parameters of the training environment (e. g. spring constant, weight of dumbbell) can be changed easily so as to obtain an environment best fitting the characteristics of human muscle. In order to accomplish the above purposes, a system must be capable of freely generating and controlling the physical and psychological elements of a training environment. For the first step, applying virtual reality techniques, we are developing a computer controlled training system which can generate and control various audio/visual images and forces to be applied to the trainee. Currently, however, we have decided to limit the scope of implementation to the upper extremity as the training target, and to visual images for the environmental information. The trainee using this system wears a force-display which can apply force to his/her upper extremity and a head mount display through which he/she can see the virtual world, a room with wall, windows, etc., in which a spring and a dumbbell are placed in the room. The trainee can "use" these sporting goods and can feel forces on his/her upper extremity as if he/she were actually exercising using them. By measuring the trainee's muscle characteristics and setting them in the system's computer before starting a training session, an improved training environment results. In addition, in the case of rehabilitation, the system can provide information such as video images of rehabilitation history data, which can help increase the trainee's motivation for attending the exercise. In our system, an important role is played by the actuators which are attached to the force-display to generate various reaction forces. An actuator serving those purposes should be safe, small, light, and capable of high force output. As human muscle of the upper extremity is much stronger than the muscle of the fingers, an actuator with high output is very desirable. It is also important that the apparatus not feel unpleasant to the trainee when he/she wears the force-display. For these reasons, we have chosen a pneumatically controlled rubber actuator.