Graph-based methodology for the kinematic synthesis of wearable assistive robots for the lower limbs

Non-anthropomorphic wearable robots (WRs) give good grounds for expecting advantageous performances over traditional anthropomorphic solutions from both the standpoints of ergonomics and of the dynamical interaction with the human body. However, the kinematic design of non-anthropomorphic WRs can be too challenging for conventional synthesis methods, due to the large number of open design parameters. To support the designer, this paper presents a systematic approach, which allows to produce the whole set of independent kinematic solutions for lower limbs orthoses with given properties. This method has been implemented to derive the atlas of independent kinematic solutions which can be used for the kinematic design of a planar wearable robot for the lower limbs. The proposed methodology includes two tests specifically devised to solve the problem of enumeration of kinematic structures of wearable robots: the HR-isomorphism and the HR-degeneracy tests.