My Final Project
The idea for my final project is an aadaptable motor for wheelchairs. Its purpose is to push the wheelchair using a motor so that the user may be able to do other activities involving the hands.
Research
The idea of working on a wheelchair began when I saw this Instagram reel and kept thinking about it. Since I study Biomedical Engineering, I thought that could be a great projet to develop. The video made me realise that there is a problem for people with disabilities and/or their carer when they have more things to do. Also it is uncomfortable for wheelchair users to keep pushing the wheelchair all the time.
Some of the existing wheelchair motors are the following:
For this project I am still deciding if using one or two wheels. I think I will be using two, as well as two motors to move them and give direction to the wheelchair. Also, it is going to need tubes to attach the wheels to any type of wheelchair, because not all of them have a horizontal tube at the back. The importance of having two new wheels and not using the ones of the chair itself is that not all of the wheelchairs' wheels are accesible. So there is no way to control those wheels without modifying the wheelchair and maintain the project as an adaptable motor. I find it important for it to be adaptable as a lot of people already have a wheelchair and it is not possible for them to afford an electric wheelchair.
About the Wheelchairs
To know more about the wheelchairs I went to the Biomedical Engineering Laboratory to observe the wheelchairs that are there. In the classroom I found that all of them are different:
For that reason I had to change some aspects of the sketch.
About Weights
The users would be mexican people (I'm from Mexico :D), so I based on this to know how much weight the motors are going to be exposed to. According to INEGI (National Institute of Statistic and Geography or Instituto Nacional de Estadística y Geografía), the average weight of mexican people is 74.8 kg. Although that's the average weight, the SENADIS (Chile's National Disability Service or Servicio Nacional de la Discapacidad) explains in the Standard Wheelchair Descriptive Sheet that the maximum user weight is usually 130 kg and the wheelchair weight is 15 kg, giving a total of 145 kg that would be carried by the motors.
I also searched for the weight supported by already existing wheelchair motors:
- Power Pack Plus: 159 kg
- Empulse R20: 190 kg
- JQ-B2 Moving Booster: 100 kg
About Motors
There are different kind of motors, but the ones I'd be using are DC motors, because they are easier to control. However, it is important to know exactly which motor is the one perfect for the project, so I researched about them.
| Gearmotors | Peak Torque | Max. Load | Size | Energy | Price | Extra Comments |
|---|---|---|---|---|---|---|
| MPW86 Wheel Drive MobilePower™ | 35 Nm | 227 kg | 86mm brushless DC gear motor, 200mm wheel | 24 V | $903 | For automated guided vehicles and autonomous mobile robots. |
| MP36 Right-Angle Gearmotor MobilePower™ Series | 109.9 Nm | - | 93 mm | 24 V | $391 | For power wheelchairs and other mobile traction applications. |
| MPP36 Right-Angle Gearmotor MobilePower™ Series | 144.9 Nm | - | 93 mm | 24 V | $567 | For bariatric power wheelchairs and other mobile traction applications. |
| MPS32 Right-Angle Gearmotor MobilePower™ Series | 108 Nm | - | 100 mm | 24 V | $464 | For bariatric power wheelchairs and other mobile traction applications. |
| Brushless DC Motors | Peak Torque | Max. Load | Size | Energy | Price | Extra Comments |
|---|---|---|---|---|---|---|
| MPW86 Wheel Drive MobilePower™ | 35 Nm | 227 kg | 86mm brushless DC gear motor, 200mm wheel | 24 V | $903 | For automated guided vehicles and autonomous mobile robots. |
About Batteries
About Regulators
Sketch
First Sketch (31/01/2024)
I have to tentative sketches, one for each of the ideas (one or two wheels).
Programming and PCB
Regarding the PCB for the project I have been working with DC motors (Outputs week) and PWM (Embedded Programming Week) in order to be able to control de motors.
