Development of Master-slave Type Lower Limb Motion Teaching System

Abstract

Motor skill learning is fundamental in many physical activities of human. In the processes of learning of motor skills, learners often receive visual or physical information about postures from teachers. However, the information about postures usually cannot be transmitted precisely. In this paper, we propose a motion teaching system to transmit teachers' motion to learners directly by using a motion capture and an assist suit. The assist suit, which has a pneumatic artificial rubber muscle (PARM) as an actuator, was designed to move a learner's hip joint with less loss of assistive force and less constraint of motion. Hip joint motion of a teacher can be transmitted to the assist suit by master-slave control. In addition, to compensate the delay of the PARM, posture of the teacher is predicted before the occurence by a recurrent neural network by using electromyogram signals and the past joint angle. We confirmed the system can transmit a teacher's motion to a learner in real time, and with the neural network, the delay of the learner's motion could be suppressed to approximately 0.1s, which is enough to feel visual and physical information synchronous. Therefore, the proposed motion teaching system would have the ability to transmit teachers' motion to learners visually and physically with precision sufficient to facilitate skill transmission.