Designing a knee brace with a controller-driven locking mechanism
Senior Design project // Client: Fidelity Orthopedic Inc. (Dayton, OH)
Duration: 2016-2017, 8 months
Teammates: Francisca Fajardo, Tin Do, Trung Do
Team roles: All team members (4) contributed to every aspect of the project. Specifically, I worked on writing all reports and deliverables including the IRB testing protocol, development of electrical components and Arduino Uno code, and overall design concept of the knee brace and locking mechanism, including mechanical design and prototype construction.
Objective
Develop a knee brace that incorporates a locking mechanism operated by an external user-controlled remote.
Automatic adjustment of brace settings (eliminating hardship of bending over and manually adjusting settings at the knee, a characteristic of currently available locking knee braces.
Has the ability to offer free range of motion, fixed range of motion, and fixed angle positions of the braced knee.
Discrete and stylish design.
Cost effective.
Made for rehabilitation purposes and as a permanent aid.
A testing protocol was also produced in accordance with and approved by the IRB (Internal Review Board) in order to test the prototype on human subjects (however, testing was not performed due to time constraints of project).
Total final cost of brace achieved: $430 (with a project limit of $500)
Concept Design
The original concept design included a locking mechanism on both sides of the knee
The updated design uses only one locking mechanism positioned on one side of the knee. Excess material eliminated to prevent bunching up of material around the knee.
The final design uses less material required for construction. Lightweight, durable, stylish, washable, and easy application/ removal.
Optimization of the locking mechanism
The design of the locking mechanism (specifically the grooved gear) is at the heart of this project. It is a completely original design and was truly a hard concept to tackle.
The challenge
We wanted to offer the user the option to restrict their range of motion at increments of 15 degrees for flexion and extension of the knee. This was the biggest challenge.
Once we designed the component with enough grooves to offer this option, we found it made the component weak; the walls between the grooves would never be able to withstand the pressure applied to them.
We were then left with the question: how do we design the locking component in such a way that it maintains mechanical durability and offers the option for motion restriction at 15 degree increments?
Innovative design
Our solution led us to a really innovative final design of this component.
It includes four inner grooves spaced adequately on one side and three grooves positioned unaligned on the opposite side.
This design actually offers the same number of angle options as the original design, but with less grooves and higher durability!
Our final design included two stoppers that move opposite and away from the center of the gear. When one stopper locks into a groove, the other stopper simply aligns with the wall on the opposite side of the gear. We only need to utilize one stopper to lock the mechanism (hence, lock the knee), but when two are present they offer more locking options from either side of the gear.
The final locking mechanism concept
Concept Branding
A stylish knee brace?! Redefining the style of a disability.
Concept branding was something my team and I enjoyed doing as a bonus to our project. We wanted to express the vision of our knee brace in a marketing and social aspect. These pictures express how our knee brace design can also appeal to a youthful and active audience in a stylish manner.
My team and advisor on the day of our final presentation.