Toru Oshima, Tomohiko Fujikawa and Minayori Kumamoto

Abstract:
In a mechanical joint drive used in robot arms, 1 actuator drives each joint. To drive joints in musculoskeletal animal limbs, in which skeletal muscles are used as actuators, a pair of bi-articular muscles drives 2 joints simultaneously in addition to a pair of monoarticular muscles for driving 1 joint. In our study, the mutual coordination of antagonistic mono-articular and antagonistic bi-articular muscles in in the horizontal arm plane were examined using electromyogram, results were analyzed by a mechanical 2-joint link model, and the relationship between the pattern of coordination of antagonistic muscles and output force generated by the arm clarified. A neural network model that generates the pattern of coordination was proposed to clarify the difference between conventional robots and animals in the force control mode for limbs.

Keywords: robot arm, bi-articular muscle, mono-articular muscle, force control, neural network model