Directional stiffness attachment design for an upper limb exoskeleton

One of the major problems in the project of an exoskeleton is the design of adequate attachments or fixations between the human body and the robotic device. In this work it has been proposed, analyzed and tested a new design for a compliant exoskeleton fixation based on metallic strips. These strips behave as a rigid interface in the sagittal plane of the arm and act as compliant interfaces to compensate for misalignments between the exoskeleton and the human limb. The design concept has been modelled and analyzed mathematically and then included in an exoskeleton prototype for the upper arm with three degrees of freedom. The load tests have provided a range of feasible values for the strips. These values have been used to build the attachments of an upper limb exoskeleton with three actuated degrees of freedom. The system is ready for tests with humans to determine the actual force transfer between the human and the exoskeleton during typical arm movements and if this system improves user comfort.