Abstract
A six-muscles model of the human arm is useful to analyze dynamic tasks because the stiffness and the joint torque can be estimated easily by the muscle activity and the arm posture angle. The estimation method of the six-muscles model is required to achieve the stiffness analysis in the dynamic task. However, it is difficult to estimate stiffness parameters on any actual tasks because the muscle model has many bio-parameters and it has nonlinear terms in the previous estimation method. We propose a new estimation method of stiffness parameters in the six-muscles model. We assume the each muscle has same elastic property and the elastic coefficients of the muscles are determined based on a common longitudinal elastic modulus. Then, well known least square method with the gradient method of the longitudinal elastic modulus can be applied for the muscle parameters estimation. Moreover, the effectiveness of the estimation method is evaluated by stiffness analysis comparing with the results in previous studies.
