Design, Simulation, and Construction of a Prototype Transhumeral Bio-mechatronic Prosthesis

This document presents the development of a low-cost, right limb transhumeral prosthesis prototype, which incorporates basic movements to recover the performance of some activities of daily living for people who have suffered an amputation of the limb above the elbow. Firstly, the anthropometry of the patient’s limb is defined, which will set the prosthesis’s dimensioning. Afterward, a mechanism is established that meets the required degrees of freedom, and finally, the prosthesis prototype is designed considering materials, dimensions, and geometry for each part. It is mainly used 3D printing by deposition with ABS material, and conventional manufacturing processes with chip removal. The elements were designed, taking into account the anthropometric measurements of a 45-year-old transhumeral amputation patient with a height of 1.61 m, a 3D scan of the healthy arm, and the stump was performed with the Eva Artec scanner. The results consist of a prototype prosthesis with 4 degrees of freedom: flexion-extension of the elbow with a range of movement of 120°, prone supination with a range of movement of 180°, flexion-extension of the wrist with a range of movement of 60° and in the ulnar-radial deviation with a range of movement of 70°, with a total weight of 1.65 kg. The transhumeral prosthesis adapts to the prototype of the “MAKI 3.0” hand prosthesis, which has only one degree of freedom and a weighs 326 g.