Study on the Influence of Cuff Width and Air Pressure on Human Discomfort of Simulated Circumferential Soft Lower Limb Exoskeleton Compression

Abstract

The physical interactions between the user and hard or soft exoskeleton are quite different, with the soft exoskeleton exerting pressure on the limb through the cuff. In order to achieve better comfort, we need to carefully study the way the cuff is covered. The purpose of this study was to explore whether there is a “critical pressure” in the relationship between inflation pressure and contact area and find the influence of different cuff widths on discomfort under different inflation pressures, so as to provide guidance for the design of soft exoskeleton and improve user comfort. 18 healthy participants were tested using two sizes of pneumatic cuffs, inflated at the middle of their thighs. The results showed that under lower inflation pressures, the wider pneumatic cuff has higher comfort. And with the increase of inflation pressures, the narrower pneumatic cuff shows higher comfort. It also proves that there exits a threshold pressure between force and contact area under circumferential compression. According to the findings, if the inflation pressure exceeds 4kPa, it is recommended to use a narrow cuff, and in order to ensure the firmness and reliability of the cuff in contact with human body, the compressive force can be appropriately increased.