Wheelchair pusher robot

A compact and simple wheelchair pushing device. It almost feels like the invisible man is pushing you forward. I have more then one additional device I can connect to my wheelchair and all of them are useful but what I was missing the most was something compact that can go into the car and can be an additional assistant when you go on a walk with your wife but the road is uphill or uneven.

See here on YouTube https://youtu.be/l2qZZt24OhY

It also should be hidden so going into a restaurant doesn't make your wheelchair much larger. I have one of these bikes you put in the front but these you need to leave outside and they are bulky to travel with.

This device is just great and not that hard to build. I have a Panthera U3 wheelchair and for every wheelchair you might need to design it a little different. So 3D printing in this case is just the right way to do this.

What I bought to make this work.

1. You need an electric wheel. I bought a spare wheel (E_Scooter 3000/3100 F lat Wheel Set 799, SEK (NetOnNet)). It has three wires to control the motor and about 5 wires (+,- and a sensor for the three stages). There is not much explanation but you can't do much wrong and you find some youtube video's that can educate how to use it.

2. You need a controller that can run this motor. Look for skateboard controllers as they have already thought about something you keep in your hand remotely. I bought (36V Single Wheel Hub Motor Electric System Driver Pulse Longboard Skateboard Controller Remote ESC Substitute - 36V - For 424 SEK)

3. You need a battery pack. I took the same one as I have on my electric bike. It doesn't matter what brand you buy but make sure you have the voltage right. In my case I had a 36V battery so I selected my wheel and controller for 36V. You have also 24V and 12V I think....

4. You need a frame. 3D printed material is not strong enough. I bought an aluminium profile kit. (Ratrig Startkit med 12 aluminium profiler 999SEK (Kjell & Company). I only needed three of 50cm so got loads for more projects. They are about 2cmx2cm wide.

5. You need two v-profiles that will hold the wheel. I got these in a do-it-yourself shop and had to make the whole a little bigger. They cost about 50SEK together.

6. The last part are a number of connectors. Like for the power supply and for the sensors. I got these in an electronic shop online and you need to do a little bit of soldering. When the motor is vibrating instead of rolling it means that you sensor wires and three motor wires need to be swapped around. I simple do a trial and error until the wheel start rolling.

7. You need some screws, axis and bolds. These you can buy in a do-it-yourself shop. I needed two axis. One that connects the wheelchair clem to the motor. Its important that the wheel has some up/down freedom otherwise you would not be able to do a wheelie...

8.. Battery is a 36V 11.6Ah BiXPower battery and connector. You have different sizes and measures but they all use the same connector. Use what you can find as long your control and battery have the same voltage. (The attach plate might need to be redesigned). (bixmart.com) The 8.4Ah should be more than sufficient.

Important to know

• Make sure that the wheel touch the floor more or less at the same line of your back wheels. This makes sure that the wheel will not be dragged aside when turning the wheelchair around it's axis.
• This design doesn't allow the motor to brake. You can make the wheel spin backwards but it will have no or low grip on the floor when you do so. This means that you need to be able to brake by hand! The wheel pushes forward because it has an upwards push while moving forward pushing the wheel firm to the ground.
• Be careful! It works for me and I have a lot of fun with this but such wheel can have a lot of power and using it wrongly might injure you or damage your chair. I connected this to the middle bar of my chair that looks strong enough for this design. This wheel I have chosen can go up to 20 per hour. No need to say that it wold be stupid to go that fast with those small wheels in front...

Fusion360 files in case you want to modify the design for your own wheelchair.
Batteryplate: https://a360.co/33miy5l
ElectronicHouse: https://a360.co/34i6y4i
HandScrew:https://a360.co/3ip8sF9
SplashScreen:https://a360.co/3jso1NU
Stopper:https://a360.co/3njWfWf
Wheelcap:https://a360.co/34nkyJU
WheelcapWire:https://a360.co/34hYosB
WheelchairClemV2:https://a360.co/33mjxT5
WheelCover:https://a360.co/30srrbS