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MiltyOO
Posts: 4
After joining and looking over this site, I think I am in the wrong place. The reading I get here is way over my head.
I have been a T-4 para. for almost 12 years now. I have a shop in the back that I work on used construction equipment and sell the same. I have been in constuction all my life and welded in necular power houses so I have that knowledge and have my shop set up to do it.
My delima is that I do not know anything about the electronics, motors, microswitches ect.
I want to build a wheel chair (I repair the 2 that I have all the time) except the electronic parts.
My first question is how do I find motors strong enough to pull my 300+ pounds arround in the sand at the beach? Do they even need to be wheelchair motors?
Do not want to write a novel on my first post so I'll end for now.
Any help would be greatly appreciated.
Thanking you in advance,
Milton
I have been a T-4 para. for almost 12 years now. I have a shop in the back that I work on used construction equipment and sell the same. I have been in constuction all my life and welded in necular power houses so I have that knowledge and have my shop set up to do it.
My delima is that I do not know anything about the electronics, motors, microswitches ect.
I want to build a wheel chair (I repair the 2 that I have all the time) except the electronic parts.
My first question is how do I find motors strong enough to pull my 300+ pounds arround in the sand at the beach? Do they even need to be wheelchair motors?
Do not want to write a novel on my first post so I'll end for now.
Any help would be greatly appreciated.
Thanking you in advance,
Milton
Comments
I might sugest downloading Whats a microcontroller and Basic Stamp yo start with. Lots of good info here in the tutorial section on home page.
As for motors I have enough power wiyh what comes with it. Do a search for power chairs and check Invacare. Sorry I dont have links...
http://www.tankchair.com/our-products/
NO?
Make your own.
http://www.instructables.com/id/How-to-make-custom-and-strong-tank-tracks-for-very/
http://www.pinterest.com/pin/68679963037882714/
http://makezine.com/2010/10/27/how-to-diy-tank-treads-from-roller/
Once you get the treads made, you will need a frame welded to the wheelchair.
Use milling machine DC motors with DC drives.
Get 2 - 40 in-lb DC Brush Servo
Get 2 - DC 1's
[IMG]http://www.ajaxcnc.com/images/DC1 small.jpg[/IMG]
You can control both DC singles using differential input.
You will need to contact ajax to learn more on the protocol and differential signal levels.
Dont ask me why im plugging these people, they are the ones who let me go in 2008, completely destroying my life, and they didn't even bat an eye.
(see how much i want to help parallax forums)
Prices here:
http://www.ajaxcnc.com/ajax-cnc-components/
Once you get that far, come back here and ask for info on what to do to control the Differential inputs using many different parallax product combinations.
Much cheaper than 30k. But you will be working your butt off, putting lots of time into it, making your own controller for the DC1's
You are now: FOUND √
Moderator Monkey,
Still dosen't look amused.
You just can't win with this guy.
don't get discouraged if some of this electronic stuff seems confusing. As somebody already suggested, have a look at this:
http://www.parallax.com/sites/default/files/downloads/28123-Whats-a-Micro-v3.0.pdf
Parallax is excellent when it comes to providing educational materials. Their beginner kits are reasonable and their materials will walk you through the learning process step by step. This forum is also here when you get stuck. My suggestion is to force yourself to read through some of the materials and don't even worry if it makes sense to you the first time through. After a couple of reads and perhaps some experiments, you will find that the concepts will eventually sink in.
Heck, if I could learn this stuff, anyone can.
Get a used power chair. Make some hubs mount the tracks I don't know how many u will need you will have to experiment.
You can even use the stock controls.
Or build your own if u get a motor driver
There is a million ways to do this.
http://m.youtube.com/watch?v=8IUOcqocCKM
Tracks are a huge expense and they are going to damage a lot of surfaces. Big tires with lots of tread would be far more versatile and cheaper.
I would also plan on using 4 motors and AWD.
Erlend
http://www.wheelchairdriver.com/
and tankchair!
http://www.powerchair-review.co.uk/tankchair.htm
Traction may not be so much an issue of more power as it is about having oversize and under-inflated tires. I just thought you might investigate this with some of the beach buggy enthusiast before you buy or build something extravagant and potentially disappointing.
An if you can't find wider hubs and tires for your chair, you might be able to make your own dual tires to increase traction. You might be the first to start a trend if successful.
4WD would be a big help as well. This could be an interesting project.
http://www.popularmechanics.com/cars/how-to/repair/how-to-drive-on-sand-beaches
Me and a couple of friends adapted an old Jazzy wheelchair we found at the local waste disposal for a mutual friend of ours. We extended the base for stability and adapted the rear axle hubs to take small tractor wheels, on the front we put 6 inch cart wheels. The front was extended with two A frames with a connecting foot plate, when the foot plate is removed the A frames swing back so it takes less room when transporting.
That was 6 years ago and that thing is still going strong to this day, the test was on compacted sand but through wooded areas it really excells, it will ride over a 4 inch fallen tree trunk like it is a twig.
I dont remember the total cost but it was less than $400 and as you might guess the majority of that was wheels and batteries. If you do a web search Im sure you will find commercial products that do the same but the cost is in the thousands.
Here is a link to a video of its Inaugural test run.
http://www.youtube.com/watch?v=ghWNa-__df8
Loopy Byteloose is absolutely right about tire pressure on sand, it runs a lot better with a lower pressure than you would use on a paved area.
This project is very much about the suspension design as it is about electronic control. In fact, I suspect a lot of people might feel the electronic control would be rather easy to hack and modify to a custom system.
If it is 2WD, I am serious about suggesting adding the motors to make it 4WD. After all, instead of merely replacing smaller 2WD motors with bigger ones, you can combine the power of both and have an added boost of 4 wheels pulling. But I really don't know if it would be unwise to have a 4WD with different available power to the 2 wheels in the front and the 2 in the back.
You may find that you just want to start with a whole new under-carriage frame and switch it out with the existing one. Once you start using things like tractor wheels, you are going to have wheel clearance problems to contend with.
It really is simple, sand requires a more enhanced suspension and 4WD to get the most traction. While it is off-road purposed, I suspect that it will be a nice ride on the roadway as well.
You could even go to 6 wheel drive if your ambitions are so inclined -- or half-track style.
to come down the ramp with all four tires nearly flat, and in 4-wheel drive. He would be down hard,(stuck), and needing a tow before he could get to Sand Highway...
We learned to not 'air down' until you must, and then if you are still spinning, then put it in 4-wheel drive.
It is really more about technique then muscle, when you are back in the sand dunes,
A large tire contact surface area is more important than weight, if you just want to cruise around the dunes at the legal speed limit.
Now, if it is Competition Hill you want to climb, then you will want to use a different type of tire, A Paddle tire, one that is designed to grab sand and throw it backwards.
and that is where the Horsepower will be needed, and the vehicle weight is kept to a minimum.
Not as much technique or finesse needed here, just 'punch it', and stay on top of the sand...:)
-Tommy
You are no longer lost. There are all kinds of people (including me), who knew nothing of electronics until they came across the Propeller… so put this on your "must have" list:http://www.parallax.com/product/32910
The problem is that there are a lot of little facts and concepts that you will need and they are best introduced by this: http://www.parallax.com/product/32910
You can cheat and download the manual and then use your activity board to go through the exercises.
I have a long term project to build a semi-autonomous wheelchair, which you don't need. You don't need wheelchair motors either, but I think they are the best(cheapest) source of power. Eventually, I want my semi-autonomous wheelchair to have 4 wheels. So, I have built and added quadrature encoders to
the current two wheel drive version. Most wheelchairs use 24V motors and sip 10 to 15A each. I am using an overstuffed controller from. If I were to do it again, I would use Parallax's controllers… go to 4 wheels immediately and only use half or two thirds the voltage.
The weight isn't the problem on sand… it is the weight distribution. The fatter the tires and the more tires you have on the ground the better.
Again, welcome to the forum. You won't find a better place to spend your time.
Rich
There isn't much I can't do with a Propeller at this point but I can't weld:)
There are several others on the forum who have expressed an interest in wheelchair related issues.
I am in central Illinois. Where r u? maybe we could hold a 5 man wheelchair convention.
Rich
Going down this road of modifications is an endless game of trade-offs.
So exploring little cheap mods first is going likely get you into seeking the best answers for you personally without too many disasters along the way.
And you are going to either have to figure out how your existing powerchair is wired before you add mods to it (a reverse-engineering research project, or you are going to have to provide a complete from scratch replacement).
A $$$ budget is a helpful starting point.
I am just taking a pragmatic approach of getting the most bang for one's buck. I'd love the $30,000 tracked chair that could climb over the neighbor's dog and up his front stairs, but just modifying the drive wheels to have dual hubs and tires might get a lot more immediate results.. no need to rewire, no need to build motor drives into wheels that steer.. no need to add more batteries And maybe easily removed if the results are a dismal failure.
A development strategy that builds knowledge as it goes and doesn't eat you out of house and home is wise. These chairs are not cheap.
Most tracked 'wheelchairs' I've seen can't handle a 9% incline, meaning they're rubbish off road.
(They're even rubbish on the road some places... )
I hve a couple of 'off the wall' suggestions...
BLDC motors used for electric bicyles, MC and car conversions...
http://www.goldenmotor.com
You can get hub-mounted motors delivering up to 1.5Hp...
For the 'normal form factor' motors, the sky's the limit, or something like that...
http://www.scaledtanks.com
If it's tracked, these guys know something about it...
(And someone there probably built a scaled down version of it... )
Some of them make tracks out of pieces of metal bolted to old conveyor belts.
Just admit it, if it's going to be tracked, woldn't you rather it used the same proven design as a tank?
* Forklift motors
* Forklift wheels and tires
* Hovercraft (there are a few on the forums that have these and perhaps could advise)
You are welcome! Glad to see you're still actively pursuing the project.