Design and Preliminary Evaluation of a Torso Stabiliser for Individuals with Spinal Cord Injury

Spinal cord injuries generally result in sensory and mobility impairments, with torso instability being particularly debilitating. Existing torso stabilisers are often rigid and restrictive. We present an early investigation into a non-restrictive 1 degree-of-freedom (DoF) mechanical torso stabiliser inspired by devices such as centrifugal clutches and seat-belt mechanisms. First, the paper presents a motion-capture (MoCap) and OpenSim-based kinematic analysis of the cable-based system to understand the requisite device characteristics. The evaluation in simulation resulted in the cable-based device to require 55-60\,cm of unrestricted travel, and to lock at a threshold cable velocity of 80-100\,cm/s. Next, the developed 1-DoF device is introduced. The proposed mechanical device is transparent during activities of daily living, and transitions to compliant blocking when incipient fall is detected. Prototype behaviour was then validated using a MoCap-based kinematic analysis to verify non-restrictive movement, reliable transition to blocking, and compliance of the blocking.