Towards Designing an Energy-Efficient Semi-Active Bipedal Walker that Performs Tai-Chi Gait

T.-Y. Wu and T.-J. Yeh (Taiwan)


Bipedal walker, semi-active, natural dynamics.


In this paper, a semi-active bipedal walker which combines the merits of powered and passive walkers is proposed. The semi-activeness is motivated by Tai-Chi, the ancient Chi nese martial art, in which the practitioner has to learn to actuate only part of his/her muscles to control the motion of the center of gravity and relax the others. Likewise, for the proposed walker during most of a walking cycle, only half of the joints are actuated to control the trajectory of the center of gravity, and the other half remain unactuated but have springs connected between adjacent links. It is ex pected that by having unactuated joints, the walker can pre serve the power saving feature of the passive walker, and by having actuated joints under active control, the walker can also achieve the stability and performance of the powered walker. The feasibility of the proposed walker, including the system design and the control strategy, is veriļ¬ed by numerical simulations and hardware implementation. Ex periments indicate that the semi-active walker consumes 80% less the electrical power of the powered walker that performs the similar gait.

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