Lan-Anh wants a device that supports her right arm so that she can lift it and manage her daily living.

About Lan-Anh

Lan-Ahn is from Vietnam and came to Switzerland through Terre des Hommes for a back operation at the age of 18. She works as a businesswoman at UBS. Due to polio, Lan-Ahn works with one hand. With the 5-finger system she is not only very efficient on the computer, but she also likes to maintain it herself. In her spare time Lan-Ahn likes to tinker with her own tools that make her everyday life easier.

Challenge

Since Lan-Ahn was 2 years old, she has had polio and difficulty lifting her upper arms. In everyday life, she therefore uses her left hand almost exclusively to support her right hand and thus bring it into a functional position. This makes it difficult for her to do two-handed everyday tasks such as cutting vegetables or rolling dough. Lan-Ahn would like a device that supports her right arm so that she can perform such activities again.

Solution

The "LanArm" project is ambitious and complex. Lan-Anh has limited motor function in her upper arms and shoulders, but she can use her lower arm and her hand. Therefore, the objective of the project was to design a system that could allow her to raise, maintain and lower her right arm from a working position (in front of her at chest to shoulder level). Only one arm was considered for the project since she is currently only use the right arm for manipulation, and it reduced the level of complexity.

After thorough brainstorming, manipulations and tests, the team could explore, validate or reject potential concepts for the support. For instance, due to Lan-Anh very shoulder musculation, a support system anchored at the shoulder like a backpack was not a viable option for her.
Following this main design constraint, the team ingeniously designed a waist support that Lan-Anh can open, close, and adjust single-handedly. The tailored belt is based on a commercial belt provided by Orthopartner AG, that have been modified to the exact needs and dimensions of Lan-Anh and is the fixation for her arm support. Multiple hinge systems have been tested and prototyped to find out what hinge could be used and where should it be located.
A commercial self-locking hinge has been selected, as it allows free movement in one direction and locks on the other. The most appropriate location for the hinge to be mounted has been determined at the back of Lan-Anh's shoulder; it enables full motion, does not block her movement and do not collide with her wheelchair when she sits. Once the hinge selected, the arm support could be prototyped using wood and metal plates.
In parallel, a custom comfortable armrest has been designed that Lan-Anh can firmly attach to her arm by herself. She is able to sweep and move her arm with the support to complete her task.
Finally, the team designed the release mechanism for the hinge using an Arduino, a servo-motor and a 9V battery. The motor was directly mounted at the hinge and allows Lan-Anh to unlock the hinge with a simple button placed at the waist and release the arm support.

The prototype at the end of the weekend was functional and enabled Lan-Anh to press a wall button in a proof-of-concept. A large part of the team is still very motivated after the event and is now finalizing the prototype to prepare it for long-term use at home. Stay tuned to see the future of Lan-Arm!