A Novel Parallel Mechanism-Based Dynamic Wearable Assistive Device for Neck Rehabilitation

This paper details a dynamic Wearable Assistive Device (WAD) for individuals suffering from chronic neck pain. Individuals should wear conventional cervical collars, which limit head mobility to a single configuration. A dynamic WAD is designed based on the human anatomical head/neck data and a dimensional synthesis study has been conducted using a loop-closure approach, based on the input parameters like dimensions of the top and base platforms and neck height have been taken into consideration for synthesis. Based on the dimensional synthesis, for the given geometrical parameters the proposed device achieved a maximum angular tilt of 19∘ for flexion, extension of 19∘ and lateral bending (right and left) of 38∘. However, a major concern in WADs is related to evaluating the performance of the device by assessing the strain on the surface muscles. To address this problem, strain gauges are considered for strain measurement on the surface muscles because they are simple, readily available and low cost when compared to electromyography. Nevertheless, based on the existing survey surface neck muscle strain measurement using a strain gauge has yet to be studied for the controlled head/neck motions. Hence, a NI-9236 C Series Strain Quarter Bridge Input Module DAQ (Data Acquisition system) is used to examine the strain generated on neck surface muscles. Experimental studies were conducted for the test subjects with and without WAD. The various neck surface muscle strain values for head/neck motions were plotted using NI DAQ Express and the results are discussed in detail and simulation studies conducted for various human head/neck dimensions using MATLAB. The obtained strain results for the test subjects were found to be satisfactory as the strain produced on the neck surface muscles using WAD was reduced by approximately 25% than the strain generated without WAD. The findings suggest that by using the proposed WAD, controlled head/neck motions can be achieved and might be used for neck rehabilitation purposes.