Exploratory design of a compliant mechanism for a dynamic hand orthosis: Lessons learned

Abstract

Abstract-This study does not describe a success-story. Instead, it describes an exploratory process and the lessons learned while designing a compliant mechanism for a dynamic hand orthosis. Tools from engineering optimization and rapid prototyping techniques were used, with the goal to design a mechanism to compensate for hypertonic or contracted finger muscles. Results show that the mechanism did not reach its design constraints, mostly because it could not provide for the necessary stiffness and compliance at the same time. Hence, the presented approach is more suited for design problems with either lower forces or less displacement. It was concluded that physiological stiffness models are an important part when modeling hand orthoses. Moreover, further research on compliant mechanisms in dynamic hand orthoses should focus on the feasibility of implementing more complex three-dimensional shapes, i.e., compliant shell mechanisms.

Design of an Electrohydraulic Hand Orthosis for People with Duchenne Muscular Dystrophy Using Commercially Available Components

“…The design criteria for the presented hand orthosis were similar to a mechanism that was designed in a previous study by Bos et al [21]. Specifically, the number of degrees of freedom, size of the design domain and maximum resultant force on the skin were kept the same.…”