Tarsusmeter: Development of a wearable device for ankle joint impedance estimation

Abstract

We present the development and basic evaluation of a new wearable device for estimation of ankle joint impedance called Tarsusmeter. The device is intended for application with persons with locomotion disabilities to quantify the ankle joint impedance, especially in cases of spasticity where the joint's impedance is expected to differ significantly from healthy persons. The lack of a simple and light weight solution to provide objective evaluation of ankle joint impedance motivates the design criteria of this device to be as such. The target application is also to quantify variable stiffness actuator based orthosis in-vivo. Thus the form factor avoids overlap with custom shapes of such orthosis. The paper presents the mechanical design of the device, physical simulations to characterize the device-leg system, the used algorithm for impedance parameter estimation, and preliminary testing of the device.

Feasibility Validation on Healthy Adults of a Novel Active Vibrational Sensing Based Ankle Band for Ankle Flexion Angle Estimation

“…Mechanical methods are commonly used in the clinical environment or integrated into the orthosis due to their high accuracy and low cost [4] . The mechanical methods usually utilize a rotating frame, attach the ends of the frame to the foot and shank and measure the intersection angle of the frame to get the ankle flexion angle [5] . However, the instruments are usually cumbersome and will be inconvenient in daily life for continuous measurement.…”