Remember timm?

[Burgerman]

Well he ran himself over!

I was rolling out of my bathroom and my tire hit the door jam and I lost my balance
and as I was falling out. My hand hit the joystick and pulled it in full speed
as I hit the ground face forward then the chair ran me over!!

Was in the hospital for 2 weeks and bed bound 2 months

Better now day by day and rehab

[martin007]

Sad experience.

[steves1977uk]

Ouch!!!! Bet that hurt a lot! Did his chair continue to drive itself forward after the joystick was released??? This is why stock programming is dangerous!

Steve

[biscuit]

Idk... Riding over myself is a new one, but I'm always dropping my jumper or hooking my sleeves over the joystick and sending the machine haring off over all manner of obstacles including handbags, car keys, feet and shins, while I scrabble at freeing the joystick. I have it programmed for a gentle glide to a halt, as I don't want to be pitched out and I feel emergency stops are best done by pulling the js back.

Mostly the things that stock programming failed me on is the turning acceleration and deceleration. The granny chairs I've had aren't too bad with that, but the proper chairs have all needed that basic programme correction. And sometimes I've fixed other, dangerous stock mis-programming, and finally I do lots of tweaking afterwards the way I like it.

[Burgerman]

Ditto. All stock chairs have frankly dangerous steer delays etc as stock. Every last one. People think its them, and they need to "learn" the chair!

All my chairs only brake when I command it (back stick). All forward and reverse DECELERATION set as low as possible. So they roll unless I purposely brake.
All my chairs have turn acc, turn dec, min turn acc, min turn dec, all set to 100 to make them turn when told, by the amount I say, when I say. And so they stop turning instantly when told to do so. Nothing else makes any sense.

All chairs should be this way as stock. Then if you choose to make them uncontrollable, thats up to you.

[slomobile]

What programming can fix this situation?
We need the chair to decelerate gently when at speed or going downhill so we don't tip over face first.
However if the chair is stopped and it gets a sudden full throttle, it should stop right away when the stick is let go.

Short full throttle duration from a dead stop only gets applied accidentally (it should stop right away)
or when going over a threshold or other obstacle (should also stop right away once past threshold)
or by a newbie that needs to learn. (nothing teaches faster than getting bucked off)
or back stick braking is a similar situation.

The ramp slope for deceleration should be proportional to chair speed, but it seems to be constant. This is easy to program into a robot with encoders but Rnet does not usually have encoders, and even on a chair that does, I don't know how to configure R-net to decelerate like that. Is this a fundamental problem of the motor compensation model not estimating RPM accurately enough at low speed, or just not having the parameters set correctly?

[Burgerman]

In this case he KEPT pulling the joystick... So no programming would make any difference. I wasnt refering to this case. Just normal use. A seat belt would have helped. And if it steered properly then he likely wouldnt have hit any door frame in the first place.

[slomobile]

In this case he KEPT pulling the joystick... So no programming would make any difference. I wasnt refering to this case. Just normal use. A seat belt would have helped. And if it steered properly then he likely wouldnt have hit any door frame in the first place.

Ah, I thought his hand came off the stick when he fell and it kept going a couple seconds due to programming. The question still stands though, I cannot turn up deceleration any more than it is now, but the run on with hands off stick when going slow in small spaces keeps pinning me against stuff.

[Burgerman]

My chairs are the exact opposite. Deceleration is set as low as it will allow. Makes for a smoother ride, easier to release the stick to slow just like lifting off the gas pedal in a car. And just like a car my brakes are by choice. In a car you press the pedal. In a chair you pull the stick back. And that stops you very rapidly.

You dont want the chair decelerating in an uncomforable way unless YOU choose this. Or it becomes jerky to drive.

Watch, http://www.wheelchairdriver.com/gopro/control.mp4
Note that this wouldnt be possible without your hand cupping the side of the controller and 2 fingers to move the stick accurately. Hand position is everything.
Rear drive, wheelies all the time, through a door 2 inches wider than my chair. Dog is used to it. Gets out he way.
This is 100% forward accel.
100% min acceleration.
Same for reverse.
Back stick braking 95%
20% forward and backward deceleration.
45% turn rate.
45% min turn rate.
90 and then back to 100 turn acceleration, minimum turn acceleration, and turn deceleration, min turn deceleration. So it turns and stops turning when told...

[biscuit]

In this case he KEPT pulling the joystick... So no programming would make any difference. I wasnt refering to this case. Just normal use. A seat belt would have helped. And if it steered properly then he likely wouldnt have hit any door frame in the first place.

I hit door jambs despite my programming. Even using the walker, when I am terribly slow. On the chair, max speed combine with less than instantaneous reactions and dropping my stuff onto the joystick so I crash the thing all the time.

I can't twist my head around why anybody would find their chair easier to control with delayed turning acceleration. That's confusing. At least mine promptly stops heading for things when I eventually tell it to.

[Burgerman]

Beats me too.
Every last chair sold is set up this way ever since some programmer decided that "turn acceleration" or rather a reduced amount of it was a good idea. So for 20 years or more every single chair sold has 4 settings that are absolutely stupid. And these mean that every last chair drives in what I call hovercraft mode.

I have removed the walls (where set) and then set:
turn accel,
min turn accel,
turn deceleration,
min turn deceleration all to 100.

This effectively makes it turn and stop turning when you tell it instead of "accelerating" into any turn input and keeping on turning ever more, long after you told it to go straight...

If the turning is then too "sharp" or sensitive you should then REDUCE turn speed, and minimum turn speed instead.

This is basically 4 walls moved, and 4 acc/dec settings set to max.
The difference on peoples faces after spending years "learning" to drive a chair tells me everything I need to know.
Nobody yet in 25 years of doing this, has ever said put it back! The difference is a chair where you never give it a thought. That simply goes where you think it should, literally to the mm. With absolute confidence. Its not a small difference. All those that never tried this will tell you that their chairs steer fine! Because they simply do not understand the difference.

Quite why they send them all out this way? Not a clue. Its dangerous and its stupid.

[thamesmud]

I once had a noxious Invacare mid drive and managed to catch the joystick on the backdoor frame entering the house. The motors kept running, I couldn't un jam the controls and the chair stayed wedged in the door skidding its wheels. I was lucky as there were a couple of lads working in my garden and they were able to lift the chair up and pull it back enough to free the joystick.
I got rid of the horrible piece of crap and won't do that again. BM types all the way for me now.

[Burgerman]

Joysticks for normal arms should be inboard of the arm centreline for comfort and so that the fingers can cradle the joystick pod to give a firm static position so that your thumb and forefinger can accurately control the joystick. And so that the joystick can never hit a door frame, and your fingers are also safe. Without this you cannot steer the chair properly anyway.

[ex-Gooserider]

My joystick is at the end of my chair arm, very slightly inboard of the centerline of the arm...
I frequently have problems with accidentally hitting the stick w/ my belly when bending over to pick things up off the floor on that side, worse in the winter when wearing my heavy coat... Probably would be less of a problem if I lost a (quite a) few pounds

The other one that has gotten me on more than a few occasions is when I'm trying to ease under a table or similar furniture and the pod barely slides under, until the actual stick hits... (usually happens in restaurants and places like that where I don't know the table...) If I'm lucky the chair bounces straight back, if not the stick can jam under the table in some random position and then the fun starts....

Snagging the stick is definitely one of the hazards of being in a chair, and it's about the only time the faster response of BM style settings is a problem, as the 'hovercraft' settings at least allow more time to recover..... (or at least scream.... )

ex-Gooserider

[Burgerman]

But a rapid response should actively push the chair back away, where it came from so actively averting the problem?
However those people that just dont get it always insist on leaning or putting their hand on it while talking to do you get a shock as you bat their hand away.

Or kids that always grab it and then run over themselves. It teaches them to stop touching stuff they have no right to touch very well!

[700R]

To prevent issues when stationary I always change the mode the moment I stop to tilt. It stops any unwanted movements either from anyone touching it or me bending to pick or move something.

[Burgerman]

Depending how long for, and is there are people that will try to lean on it (happens all the time) then I just turn off or to speed 1 which is practically the same thing.

[Burgerman]

Do you get those people that think they can grab hold of the chair to prop themselves up? Or hang a bag on it? Such as in shopping centre lifts. Really pisses me off. I usually turn fast or reverse into them a bit. Soon wakes them up. Likewise they all pile into a lift before you get chance to turn to face forwards? Well I do it anyway. Just do it slowly and keep turnng. They all do a sort of dance and get out of the way. I lost patience with the ignorant or stupid many years back.

[thamesmud]

I find running the seat up a bit in shopping centres helps a lot with keeping people out of the way. I don't know if it because of the eye contact or the fact that the chair just looks a lot more imposing, more scary shit than awwww poor thing.

[700R]

Absolutely! People tend to think my chair is there for their convenience until I tell them. People that you don't know attempting to lean on it get short shrift though and often words aren't necessary just a flick of the joystick. The CJSM2 is not the best protected bit of kit when it comes to people leaning on it or using it as a steady. Again, I have to act fast to prevent easy damage. I've regularly had people lean on my armrests when seated but it doesn't last long. It's not a territorial thing but I need all the chair to correct positioning or moving when I want to and not after seeking approval. I'm sure to those that are oblivious or just plain ignorant they must think we are the rude ones carrying a chip or two.

[700R]

I find running the seat up a bit in shopping centres helps a lot with keeping people out of the way. I don't know if it because of the eye contact or the fact that the chair just looks a lot more imposing, more scary shit than awwww poor thing.

They way we present ourselves does factor in to how we are looked upon but the stealth raiders appear from nowhere sometimes and still need politely but firmly informing you aren't up for sharing.