Wheelchair assistence...

[urosv]

Hi Guys...
Is there a way to build wheelchair assistance pushing with PW-12H. The idea is that person who uses wheelchair is not capable of steering and using Joystick / Hum motor KIT so the transportation is only done by healthy man who is pushing the person. This person is old and can no longer push everywhere so he needs some sort of assistance. What can be used to best solve this problem.
 Thanks for any ideas...

[GM Canada]

There is no rule as to where you mount the joystick. You could mount it near the push handles at the back.

Gary

[urosv]

Since there is no need for steering and extra costs I will ask differently. Need two motors, throttle control on the handle behind and 2x 12V12Ah at the bottom, and thats it ? Now there is a problem at PW-12H if EM brake will work and what is with the wiring schema on such...?

[Bikemad]

Since there is no need for steering and extra costs I will ask differently. Need two motors, throttle control on the handle behind and 2x 12V12Ah at the bottom, and thats it ? Now there is a problem at PW-12H if EM brake will work and what is with the wiring schema on such...?

As powered steering is not required, one motor should be sufficient to provide the required assistance.
If a single wheel was mounted centrally behind the wheel chair, it would have to be able to pivot sideways to give a caster action, making the steering much easier.

A single wheel in the centre should leave enough room either side of it for the feet of the person doing the pushing.

It might also be possible to come up with some form of hinged swinging arm assembly that would allow the motorised wheel to be raised when not in use, in order to alleviate any unwanted resistance from the geared motor, when pushing without motor assistance.

If the wheel chair was stable enough, an additional seat and fold down footrests could possibly be added for the driver to use on the flat or downhill when they'd had enough of pushing.

A 16" Magic Pie (with the speed suitably limited) would certainly be interesting.

Alan

P.S. I was just looking for some wheelchair pictures and discovered that someone's already developed a single wheel drive device called a powerstroll.


It just needs a seat and some footrests and my original idea would have been completely realised.

 

[urosv]

Bikemad, nice solution but to much "stuff".
What kind of electrical connection schema does PW-12H have ? I'm sure that there is also different gearing inside to suit wheelchairs others are not as suited as PW-12H. There is no need to be directly on centre it can be at the side also. There is no big speed and sudden drag. The simple way is to replace one wheel if the other is the same width.

[Bikemad]

What kind of electrical connection schema does PW-12H have ? 

I have attached a couple of diagrams taken from the user guide which clearly shows all of the connections.

The thick black and red wires are the motor wires and the two thin red wires on each motor are for the brake mechanism.
I would assume that the brake unit needs to have a constant voltage supplied to disengage it, so that the brake would automatically be applied if the battery accidentally became disconnected.

If you are intending to use a basic brushed speed controller instead of the Joystick Version it might make the wheelchair more difficult to steer. You could alternatively use a 48 volt battery and controller and then wire the two motors in series which would give much better steering. As this is a brushed DC motor, reversing the motor wires would also reverse the direction of the motor.

According to the Dimensional drawing the wheels have an 18mm diameter axle to attach to the wheelchair. I have modified a diagram of an existing mounting bracket to hopefully show the correct sizes. (see attachment below.)

If you did use a single motor, and the wheel was offset too far to one side, it would continually try to turn the wheelchair one way when climbing hills, and the other way when decelerating down a hill (or reversing up it), making it difficult to maintain a straight line.
I would be like pushing a loaded supermarket trolley with a stiff wheel on one side.

Alan
 

[urosv]

Can you comment this picture. Is this the right configuration and is HUB24S the right motor for this. Single shaft will be used because it is simple and holdings will be replaced accordion.

[Bikemad]

These motors are intended to be fitted as fixed rear wheels, and I think it could cause a problem with the steering if fitting them on the front with the pivoting caster action, unless you get them perfectly centred on the same centre line as the pivot assembly.
Because of the amount of movement (at least 360 degrees) required by the front wheels, I think the motor cables could easily become entangled, or may even fail due to fatigue caused by the constant movement.

Although the BAC cruise controller has the ability to be set for brushed or brushless motors in the software, I'm not sure how the motors would actually connect to it, but I'm guessing they would just use two out of the three phase wire connections.

Alan
 

[urosv]

Comment on pivot problem is real. Thanks. 360 degreees rotation is disabled with some sort of block screw so wires are not in danger. Maybe it would be easier to use HUB24A -- 8" Brushed Gear. Is there any detailed drawing on dimensions of this motor and the tire material if it can be used for wheelchair in this configuration on the image ?

[Bikemad]

360 degreees rotation is disabled with some sort of block screw so wires are not in danger. Maybe it would be easier to use HUB24A -- 8" Brushed Gear. Is there any detailed drawing on dimensions of this motor and the tire material if it can be used for wheelchair in this configuration on the image ?

In order for the wheelchair to go backwards in a straight line, the castering wheels must be able to pivot through 180 degrees in either direction (360 total) or the wheels will just lock up. To steer in reverse would need much more than 360 degrees of movement.

I honestly don't think that front wheel drive is going to be feasible, unless you are prepared to fabricate a purpose made steering mechanism, which would have to be linked to a steerable set of handlebars mounted on the rear.

I can't see any dimensional drawings for the HUB24A, the drawing links show a HUB24M, which isn't even mentioned on the site:



Bear in mind the axle on this motor is 211mm wide with wires exiting from both ends!

Alan
 

[urosv]

The rotation will be possible ~300 degrees, not entirely disabled, just for the wire's sake. The wheel holder should be fabricated from scratch. The user cant handle the wheelchair so only the man behind rudder can steer and push. The motorized wheels will only be there to help. The back 18" wheels need to be modular to put them on/off instantly so rear kits are not possible, also another middle motor is not possible. I still think that front solution is the best compromise, not the best solution but it will do the trick. Is there a problem attaching 902/902 controller to 2 motor configuration ?

[CarlT]

Is there a way to make a push-pull throttle for a power-assisted wheel on a wheel chair? It would be similar to the powered walk-behind mowers where when you push the mower or wheelchair, it powers up and when you pull it powers down. I don't now if you need reverse, so basically it could perhaps the gear could disengage when you pull on the handle to back up the wheel chair or put it on a wheelchair lift. Basically one or both of the handles could be the push-pull throttle.

[urosv]

CarlT: If I understand you correctly you want to have a button for forward or/and button for reverse. If so I want to tell that ordinary throttle handle is best solution since wheelchair motors don't reach heigh speed. If you need this anyway, we talked about and Bikemad also presented a solution : http://goldenmotor.com/SMF/index.php?topic=2851.0