Study on the Effects of Rotation Axis Misalignment in an Exoskeleton-Human Hip Joint

The paper presents research on one DOF (Degree of Freedom) hip joint of an exoskeleton regarding the possibilities and effects of rotation axis misalignment in the hip joint. By rotation axis misalignment, we understand the difference of alignment between the hip joint axis of rotation in human and exoskeleton; we also consider only parallel, not angular axis misalignments in our model. The proposed approach for the development of exoskeletons is to take into consideration inherent axis misalignments and analyze the possibilities to reduce their effects on the ergonomics of the device. The first step in this approach is the quantification of effects of rotation axis misalignments in exoskeletons and to achieve this, we developed the kinematic model which is presented in this paper. Most approaches focus on perfectly aligned axis of rotation, while this is not the case in our study, we focus on an acceptable misalignment for the user.