Basic research on power limb using variable stiffness mechanism

The number of aged people is increasing rapidly and this problem will be more serious in Japan. For this reason, there will be many disabled people who have difficulty in walking in the near future. As one area of engineering support for them, a new control method and mechanism for a power limb are proposed in this paper. The main function of the power limb is to support and transport the human body, and so far, electric motors have been used as actuators. However, a general control method for the power limb has not been established. Furthermore, there is an important problem that the mechanism using only motors costs a large amount of energy during walking. In this paper, past research for artificial legs including power limbs and their problems are reviewed, and a new method for the control of a power limb is proposed. First, to realize effective walking, a novel method for determination of walking parameters is identified. Next, a new design method using variable stiffness to suppress the energy consumption at the knee joint is described. The simulation results show the effectiveness of the proposed method.