FAQ

What is the purpose of the project?

Our project is focused on helping people with degenerative arm functioning and assist them with doing everyday lifting tasks. As mentioned throughout, people with muscular dystrophy, more specifically becker muscular dystrophy and brachial plexus palsy are the targeted group. However, the device will also be suitable for anyone who is looking to improve their arm functionality.

What is the weight constraint on the arm?

On average, an arm weighs about ~5.3% of your total body weight, depending on your gender, among other factors. A leg is about 17.5%. This means for a 150lb average human being, an arm weighs ~8lb. According to this information, making the exoskeletal arm more than 5-7 pounds would cause a considerably large weight to be bearing down on the arm. Considering that people who would be wearing this device are people who are already impaired arm functioning, it will be crucial to make the device under 7 pounds.

Will the device bear down on the arm, not allowing it to be lifted up?

As said in the question above, the weight constraint should be enough to make the arm light enough for the average user to lift. If it is found through testing that the device is too heavy or changes the neutral position of the arm, a back brace will be incorporated into the design.

How will the program be controlled?

The power of the motor will be controlled by using basic circuit theory. Batteries will be connected to a circuit with varying resistor combinations that will alter the output voltage of the circuit and thus give differing ranges of power. These circuits will be connected to different switches which will be accessible to the user in their fingertips.

Update: The arm will be controlled by using the arduino environment. The Arduino is a micro-controller that can be programmed to control various electronic components. The Arduino is used in a circuit with transistors, resistors and relays to switch the motor on and off.

Update: The final design that was used to control the prototype was a relay board with two relays - each controlling the one direction of movement of the motor. These could be switched on and off using two buttons.

What are the dangers and how are they being avoided?

The most significant hazard that could occur with using the device is the malfunctioning of the motor. The motor might produce too much force to hyper-extend the arm or even break it. To avoid this from happening, the circuit will have a fail switch along with the power control switch that can be pressed instantly to cut of the entire circuit.
Another danger might be the use of high capacity batteries and wires close to the body. Proper casing of the wires and batteries will be implemented to avoid these.
Dangers concerning the comfort of the device will be be only dealt with once a working prototype is made.