PAL

Prostheses can help amputees to live more independent, healthy and active lives and lets them be part of the society with lesser limitations and stigmatization. However, access to these devices is extremely limited, and even when they are accessible, prostheses are often not accepted by the users due to a lack of functionality, comfort and appearance. The industry today focuses on high-tech products, while simpler, more affordable solutions are being mostly neglected. In this thesis project, I tried finding ways to improve accessibility, functionality and acceptance. I did this in close collaboration with users, stakeholders and my collaborating partner Agile Robots. The final concept combines advantages of both electric and mechanical prostheses in a completely novel way.

The prosthesis can be cost-effectively tailor-made and customized using a configurator software based on the users’ individual needs and desires. This process is facilitated by leveraging technologies like 3D-printing to reduce cost and manual work effort. It is cable-actuated by body movements using a breathable undershirt that is locally reinforced to equally distribute the pulling forces. The detachable shirt is worn under the regular clothing. Using body power eliminates the need for heavy batteries and motors, allows for intuitive and fast control and creates natural force feedback. A lock-switch can be triggered myoelectrically by tensing the muscles in the stump. It locks and unlocks the grip, which facilitates moving around with a grasped object. The energy needed for the switch can be harvested from the users’ movements. The hand can perform the three most important grips in a reliable way, and it can be cleaned using a washing machine or a dishwasher. Users can also attach inexpensive, 3D-printed modules for specific activities to the prosthesis. When turning the wrist, the flexible socket creates a natural form transition to the arm.