Experimental comfort assessment of an active exoskeleton interface

Walking assistive devices are designed to improve the mobility of the user. Although promising, active devices have a problem: they become uncomfortable after prolonged usage. Large motor torques provided by active devices effectively assist the movements of the user. However, these torques transfer forces to the user's limbs creating significant discomfort and limiting the duration of usefulness. This work used force mapping in an attempt to identify zones of pressure concentration that may cause discomfort as well as examined the effect that various pads had on these zones. The device tested in this research was the K-SRD TM by B-Temia Inc. Force analysis identified certain zones of high force concentration. Possible causes were identified and potential solutions were suggested. Furthermore, the padding testing showed that the force transfer was similar regardless of the thickness of the pads. However, the stiffer padding materials distributed the forces over a greater area and decreased the pressure at the interface. This seems to indicate that the thickness of padding is less important than the distribution of applied forces. In all, interfaces that distribute forces over large surface areas may be beneficial. Further research efforts are needed in order to develop a physical human-machine interface that will ensure the success of exoskeletons in the future.