Naturally Compliant Dexterous Anthropomorphic Hand via Novel Modular Soft-Rigid Hybrid Robotics Approach: Design Rationale, Assembly Methods, and Evaluation

In this paper, we propose a modular soft-rigid hybrid (MSRH) approach for designing a highly anthropomorphous and dexterous robotic hand. This MSRH approach allows the robotic hand to possess an inherently soft and compliant interface suitable for pHRI while maintaining the structural rigidity of the robot with the usage of rigid skeletons. We share the details of the design rationale, fabrication and assembly methods, and evaluation of the first prototype. Even though the presented prototype is scaled to be 125% of the average human hand, the mechanical components only weigh less than 450 g. The modular design approach allows the MSRH hand to have low manufacturing costs and a short lead time. Creation of the presented prototype costs less than ${\$}$100 CAD and can be built in three days from scratch with two-person labour. The usage of pneumatic soft robotic actuators also provides flexibility over choosing the number of controlled DOF and joint coupling. This hence provides a new angle to tackle spatial constraint that normally arises in robotic hand design with increased anthropomorphism. Lastly, the dexterity of the proposed hand is demonstrated by evaluating the hand using taxonomies highly relevant to replicating tasks humans perform daily.