Human Joint Impedance Estimation With a New Wearable Device Utilizing Snap-Through Buckling of Closed-Elastica

We propose a new wearable device for human joint impedance estimation. The device utilizes snap-through buckling of closed-elastica to impose perturbations on human joints. Actuation is based on the law of momentum conservation, that is, the proposed device induces an impact on human joint dynamics. The snap-through buckling generates a comparatively high velocity even with small actuators, and thus, the device is significantly lighter in weight and more compact compared to conventional systems. In addition, it can impose a torque perturbation on a human joint within a sufficiently short time period. Because of the perturbation in the short period, the estimation algorithm also developed in this letter enables us to consider the resulting response as an impulse response, and thereby no synchronization between the input-output data is required. We conduct pilot tests to verify the proposed method for ankle joint impedance estimation and discuss the basic performance of this method compared to the related work. We also discuss the viability of using this method for a variety of purposes in human joint impedance estimation.