Evaluation of Control Interfaces for Active Trunk Support

A feasibility study was performed to evaluate control interfaces for a novel trunk support assistive device (Trunk Drive) namely, joystick, force on sternum, force on feet and EMG (electromyography) to be used by adult men with Duchenne Muscular Dystrophy (DMD). The objective of this study was to evaluate the performance of the different control interfaces during a discrete position tracking task. We built a one degree of freedom flexion- extension active trunk support device that was tested on 10 healthy men. An experiment, based on Fitts law, was conducted whereby subjects were asked to steer a cursor representing the angle of the Trunk Drive into a target that was shown on a Graphical User Interface (GUI), using the control interfaces mentioned above. The users could operate the Trunk Drive via each of the control interfaces. In general, the joystick and force on sternum were the fastest in movement time (more than 40%) without any significant difference between them but there was a significant difference between force on sternum on the one hand, and EMG and force on feet on the other. All control interfaces proved to be feasible solutions for controlling an active trunk support, each of which had specific advantages