In the United States there are between 236,000 and 327,000 people with spinal cord injuries related to trauma. These injuries are one of the main causes in decrease movement in the upper and lower arm . Due to the decrease in functionality of the arm, many of these people can no longer perform daily tasks such as eating or brushing their teeth.
The creation of a device that would help the patient perform these tasks would allow the user to regain independence. With this idea in mind an assistive robotic brace was developed.
The final design allowed the arm to flex, extend and rotate at the elbow. These motions were provided by one of two actuating forces and consisted of actuation points on the upper and lower arm and cable guides. The main pieces in the software-driven architecture included a Raspberry Pi as the central communication tool and two mbed platforms.
One mbed controlled EMG information and the other controlled the actuators.. Mbed code has been produced to interact with the API and to drive McKibbons, Stepper, and DC motors. Mbed code has also been written to communicate with and use the EMG that was built for this project.
All the mbed code is interrupt driven with single byte instructions from the Raspberry Pi. In the EMG code a main timer interrupt handles reading and basic single processing while a main loop handles board communication.
This code handles squared sums of the data for the RMS signal processing, but rectifying and normalizing the single for more advanced processing would be handled by the Raspberry Pi. The motor driver code runs a single main loop with sensors and motor outputs being read, processed and issued to satisfy arm force or velocity control.
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