AMPOS

Posted on Monday, March 28th, 2022

Client	Chris Kraft
Professor(s)	Howard Rosenblum,
Program	Electrical Engineering Technology, Computer Engineering Technology, Mechanical Engineering Technology.
Students	Team Lead: Jonathan Mann Team Members: Mulham Hajjat, Meech Lamirande-Kabussa, Amanda Mullen, Bhavneet Singh

Project Description:

This project is focused on helping people with temporary or permanent conditions when they are unable to control the flexion of their knee. The brace is designed to be very convenient to use because, unlike a normal brace that keeps the knee in place and doesn’t allow movement, this brace can sense when the knee is required to be locked and unlocked giving more flexibility and comfort while walking. The other smart-brace options that are currently available in the market, based on a similar concept of locking and unlocking when required, are prohibitively expensive and unaffordable for many people who could use them; however, the goal of our brace’s design is specifically to reduce the cost while providing a similar user experience as the much more expensive alternatives.
The knee brace unit is designed around an electromagnetic brake, which has been attached to a series of gears for increasing the torque figures, holds the knee in extended position if the pressure is put on the affected leg. Once the pressure is released from the leg and user proceeds with walking, the unit senses this change and unlocks the knee so that the leg can be flexed (folded backwards) as normal. This cycle of locking and unlocking carries on in accordance with the gait cycle of the user. For determining the phase of the user’s gait, a combination of sensors is used to collect data. These sensors include pressure sensors beneath the foot to determine if the pressure is being put on the affected leg, an angle sensor to determine the angle of the knee joint and detect when the knee is fully extended and ready to be locked, and a fall sensor (accelerometer) to detect any event of user falling or stumbling. The communication between these sensors is wireless and is carried out using Bluetooth modules. All this information is fed to a micro computer, in this case a Raspberry Pi Pico, which has been programmed to take in the sensor data, determine the resistance needed, and provide voltage to the brake to lock or unlock the knee at the right position and time. The system runs on a portable battery pack which can be carried around the waist.

Note:
Our product is a prototype version and is therefore made by using 3D printing methods. Further designs will need to be more durable to support sustained bodyweight.