Recently I had opportunity to talk with two SMA child families and discuss issues in existing exoskeleton solutions. Before that, they mentioned rubber bands of Angel Arms and Magic Arms are difficult to setup, and change its characteristics over time. I came out with a new idea and wanted to verify it with them.   I prepared some generic images of concepts and ask the parents to choose the most comfortable in their opinion. I tried not to bias their decisions, and restrict myself to raw description. A-B test used with parents   They agreed elimination of rubber bands and separation active and passive modules were good starting point.   I did several design choices to follow: the device should be fully mechanical the device should be counterweight driven the active (counterweight) module should be separated from passive (exoskeleton) module passive device (exoskeleton) could be mounted to corset forearm axis should be always

  Another low budget 3D printed arm exoskeleton is one released by Magic Arms . This is the most advanced (lo budget) project so far and evolved from well known among children’s orthopedists WREX. WREX is acronym of Wilmington Robotic EXoskeleton and is apparatus for automating arm and grasping movement training for rehabilitation of patients with motor impairment , as stated in headline of its USpatent .   Basically WREX design is more resistant to misalignment on the cost of complexity. It adds second arm to first stage of exoskeleton to always position elbow yaw axis equally and enlarge range of motion.   I printed exoskeleton believed to be Magic Arms from files from my friend physiotherapist and tested with boy who was using Angel Arms before. I used Form Futura HDglass for its FDA approval and Carbonfill for its stiffness as a main materials. Unfortunately the device I made was too large (printed without scaling), heavy and coarse to give a good results. Main problem i