Evolution of the Utah Arm to Improve User Function

Abstract

An ambitious re-development of the Utah Arm was guided by direct clinical feedback, producing a list of features to improve the full-electric prostheses. The goals of the development focused on the following: • Smoother transition from elbow motion to hand function, and vice versa, i.e., more effortless locking and unlocking by the wearer, with many more locking positions. • Quieter operation of the elbow, both during the locking and unlocking operations (which can produce an audible “click” of the lock pin}, and during the powered freeswing function, which produces audible motor and gear noise. • More convenient connection of the prosthesis to the prosthetist’s or therapist’s computer for adjustment and training, which required a hard-wired connection of cables. • Wider range of input devices, as well as TDs, to take advantage of all available input sensors and output devices. Rather than “start over”, the technical capabilities and approach of the existing Utah Arm fullelectric system were used as a starting point, giving more advantages than disadvantages. Development time is greatly shortened by taking the approach of modifying an existing component, without the risks of using unproven designs. It is important to realize as well – the product is intended for clinical, rather than laboratory use, so practicality is of a very high priority.