Estimation of mechanical impedance at end effector of arm based on frequency analysis

Comprehension of the arm condition is important for realization of effective rehabilitation support. In this paper, the measurements of the estimation of the impedance at the end effector of the arm are performed based on frequency analysis. Two experiments of the active muscle condition and relaxed muscle condition of the arm are carried out on the three directions determined in accordance with the functionally effective muscle (FEM) theory that the output direction at the end effector of the arm is derived from the output of the specific muscle groups. These experiments indicate how much the arm can increase the stiffness of the each direction at the end effector of the arm on the FEM theory. The experimental results show that the condition of specific muscle group can be evaluated from the impedance at the end effector of the arm.