PROJECT TITLE :

Assessment of Multi-Joint Coordination and Adaptation in Standing Balance: A Novel Device and System Identification Technique

ABSTRACT:

The ankles and hips play an necessary role in maintaining standing balance and also the coordination between joints adapts with task and conditions, just like the disturbance magnitude and type, and changes with age. Assessment of multi-joint coordination requires the application of multiple continuous and freelance disturbances and closed loop system identification techniques (CLSIT). This paper presents a completely unique device, the double inverted pendulum perturbator (DIPP), which will apply disturbing forces at the hip level and between the shoulder blades. In addition to the disturbances, the device can provide force fields to review adaptation of multi-joint coordination. The performance of the DIPP and a completely unique CLSIT was assessed by identifying a system with known mechanical properties and model simulations. A double inverted pendulum was successfully identified, while force fields were ready to keep the pendulum upright. The estimated dynamics were similar as the theoretical derived dynamics. The DIPP features a sufficient bandwidth of seven Hz to spot multi-joint coordination dynamics. An experiment with human subjects where a stabilizing force field was rendered at the hip (1500 N/m), showed that subjects adapt by lowering their management actions around the ankles. The stiffness from upper and lower section motion to ankle torque dropped with 30percent and forty eightpercent, respectively. Our strategies enable to check (pathological) changes in multi-joint coordination with adaptive capability to take care of standing balance.