Strip-driven devices for the spatial motion guidance of human joints

Orthoses and exoskeletons need devices that can replicate the natural spatial motion of human joints. These devices should be simple and should have a high accuracy, in order not to constrain and load the joints unnaturally. In this study, strip-driven devices are proposed to guide the spatial joint motion. Classic planar devices are generalized to obtain rolling without slipping between two ruled surfaces. The special case of spherical motion is presented and analysed in details. The influence of several design parameters on the kinematic and static behaviour of these devices is also presented.