Feasibility study of an upper arm support based on bending beams

People with neuromuscular diseases request an arm support close to the body for assistance with their arm movements. This paper proposes a concept for a passive arm support based on bending beams to support the eating movement and that is close to the body. Simulations resulted in the final configuration and dimensions of the beams, optimized to balance an arm. One Carbon-fiber-reinforced polymer beam with dimensions 0.22×0.0041×0.0027m at the medial side and one at the lateral side of the upper arm deliver the required energy for balancing the arm. Experimental evaluation of a prototype demonstrated the technical principle; more than 87% of the moment around the shoulder was balanced between 0 and 1.1rad. A second prototype was built for evaluation of the concept in relation to the body. The width of the elastic and structural elements was only 2× 7.5mm, which is more than four times smaller than in current arm supports. From this it was concluded that bending beams have the potential to make an arm support that is close to the body an can balance the arm in a single plane.