Q Logic 3 Programmers

[Raro]

I give up.

I can't believe it

[Burgerman]

By reducing compensation in error, in order to try and make a chair smoother due to inability to use controls properly you are destroying every thing the complex algo that drives the chair is trying to do. And making it dangerous at the same time.

[Flagmax]

Adjusting the Load Compensation on my Invacare Aviva RX20 US version with Dynamic Linx has been the best thing I have ever done.

I state my case, these are just a few responses from actual Aviva owners

"The drive is totally different. I have the program key and it's still a little jerky."
"I agree. The jerkiness is ridiculous. Can't have anything hot when moving about the house. Tried to adjust the controls and not any better. I have to position the chair to point forward to move or it throws you to which ever side the tires grab. Tearing up my carpet! "
"I used it, tried to get used to it, and experienced all the things you’re talking about here - crappy rough jerky driving, crappy loose programming, quality of life decreases and physical pain as well."
"Everything on this thread is exactly what I'm experiencing. My quality of life and self confidence in managing all parts of my life-- professional job, driving my van, moving down narrow sidewalk, visiting homes of friends, etc.-- has gone downhill dramatically since I've been using this wheelchair. Has anyone come up with any adjustments/modifications that help? I'm at my wits' end!"
"The Aviva sits in my basement collecting dust. I also hate: 1. Slow top speed, 2. lack of fine control through the joystick."
"Nope, every issue you’re describing i’m also having. I’ve had quickie chairs for years and they changed to invacare and there is nothing I like about it."

The common complain is "jerkiness". How could so many people be experiencing the same issues? Some tried to adjust settings but to no avail.

Are you going to trust Invacare to correctly set the Load Compensation on a chair they used bushings for front casters?

Lowering Load Compensation is as dangerous as Lowering Speed. I tried at zero, it basically makes the chair gutless. No, it does not takes off when loaded. Now if you increase it too much, that is dangerous. The chair starts bucking like a wild horse. Again, I tried both.

To get the best performance out a chair the Load Compensation should be adjusted as the motors age. If you install new or different motors, the Load Compensation needs to be adjusted. This should be done before you adjust Speeds, Acceleration, Deceleration, Torque/Power, etc. Load Compensation affects every other setting.

Implying that the jerkiness is "due to inability to use controls properly" is wrong. I know people that some drive with their fingers, hand, shoulder, chin and foot. Trying to tell them how to hold a joystick is ridicules'. If you barely move the joystick, and you hear the brakes release and the chair jumps or jerks and starts moving, then more then likely the Load Compensation is too high.

Anyways, this info is based my personal experience (many hours testing) and reading few service manual and seeing video's of other people setting the Load Compensation.

In the end all that matters is that it worked for me. Now I even setup up a profile based on your "To make a powerchair STEER PROPERLY" post This thing is a rocket now

Regards.

[shirley_hkg]

You hit the nail on the head.

[Flagmax]

Can I bill you for new tires since the rocket profile is so fun outdoor but I the tires are going to be shot in a jiffy with the way I take corners

[Burgerman]

Do they slide when you decelerate and turn at the same time?
Mine dont.
If yours do the chair is way too nose heavy! And again on a slippy surface or smooth tiles you lose contol. The tyres shouldnt slip.

The "rocket" profile should work perfecly indoors too. You should never need any other profiles. As long as you set all the minimums correctly.

As for compensation it is dangerous to set it low. But its not obvious why until you experience control loss. Because in order to have proper control in a situation where 1 wheel sees some resistance then theres no correcton. So you fall off that ramp or try to correct via the joystick and when that resistance is overcome the chair now runs away in the direction you were correcting. Because you have too much "gas"... Compensation works fast. More or less instantly. Not like the corrections you make with your stick. And independently on each wheel. You cant do this because that all depends on the corrections you make.

Same applies when say trying to overcome a curb or even a small threshold. You might need full "stick" with low compensation. In order to make it ramp up power high enough. Then once power rises slowly at your choosen acceleration rate it may be at 24V. Then it climbs the threshold or curb, or raised edge on one wheel etc. And now you have max gas, it shoots off like a rocket as resistance gone! (with different resistance at each wheel - so not in a straight line either!) and then you have to try and shut down power before it runs into something or flips... But you cant do it fast enough as your deceleration and turn rates you programmed in means that takes too long. Much longer than compensation. That reduced power as the chair reached the top of the obstacle.

Now it POSSIBLE that compensation is set too high from the factory. But thats extremely unlikely as every time they turn it on and move it it will be obvious to anyone. But they may have done that to try and make it turn in place properly with a stupidly nose heavy and dodgy caster setup. Possibly.

The common complain is "jerkiness". How could so many people be experiencing the same issues? Some tried to adjust settings but to no avail.

Because most preople and most experts are frankly idiots. They have no clue or no OEM programmer and wouldnt know how to use it to save thir lives. Plus in the case of your chair you can adjust compensation in a thousand ways not just higher or lower. You can also adjust initial movement damping, and initial torque to aid turning seperately from forward/backward etc. THAT is how you should be making it smoother not reducing compensation. And non of this will work properly if its nose heavy.

To SET compensation do the following.
Set speed to the lowest possible. Indoor on 1.
Drive on a flat surface at speed 1 FULL STICK. So its going 1 mph. As it approaches a steep ramp and begins to climb it, does it slow AT ALL? Does it speed up AT ALL? Be very vigilant. Listen to motors.
If set correctly it will be absolutely constant speed.
If it slows increase compensation.
If it speeds up decrease compensation.
Steep ramp...

[Burgerman]

Implying that the jerkiness is "due to inability to use controls properly" is wrong. I know people that some drive with their fingers, hand, shoulder, chin and foot. Trying to tell them how to hold a joystick is ridicules'.

No it isnt. I have programmed dozens of peoples chairs over the last 27 years. And its literally impossible for any user including me to drive my own chairs with any kind of accuraccy unless you hand has some reference point or that you can move the joystick with mm accuracy over uneven ground, bumps, and for high levels of acceleration not to feed back into the controlof the stick. For people that cannot do this we have to make quite huge compromises to almost all of the settings. Which may allow them to have better control, but not great control.

Imagine trying to fly a RC heli while you ONLY touch the sticks. With someone else holding the transmitter... How do you suppose that would work out.

So first job when someone comes here is to FIX the joystick position, in some way that they have at least better control and some fixed refrence point. Maybe a velcro strap in a arm. Whatever it takes. However you do it. Hovering over a joystick with all your hand or fingers grabbing it from the top, while arm just rested on the chair just cannot work. Unless you reduce turn speeds, acceleration and deceleration rates to levels that I consider rediculous.

If you barely move the joystick, and you hear the brakes release and the chair jumps or jerks and starts moving, then more then likely the Load Compensation is too high.

Thats caused by many things.
1. Minimum forward acceleration.
2. so called Torque. Which is not really it simply ELEVATES the initial stick movement (so instead of the joystick movement starting at 1% it begins at say 5%. And still ends at 90%. The idea being that the chair starts to move instantly at VERY SMALL STICK MOVEMENTS. on heavy carpets, a ramp, or whatever.
3. Damping. This smooths the transition from that 0% to the next position.

By attempting to do this by reducing overall compensation you cause other control mixing problems that change as load increases making accurate steer response on uneven terrain or lateral slope unpredictable.

[LROBBINS]

It is quite possible that somewhere in its history Invacare changed the motor (and or wiring - remember that Invacare had a mandatory recall some years back from wiring fires) from high impedance to low impedance and "forgot" to change compensation. Given the overall level of incompetence, it is conceivable that they then put it on the market without ever noticing that it was on the edge of disaster (or even ever driving it)!

[Burgerman]

To SET compensation do the following.
Set speed to the lowest possible. Indoor on speed 1.

Drive on a flat surface at speed 1 at FULL STICK. So its going about 1 mph. As it approaches a steep ramp and begins to climb it, does it slow AT ALL?
Does it speed up AT ALL? Be very vigilant. Listen carefully to motors.
If set correctly it will be absolutely constant speed. The ramp alone, no matter how steep should not affect the speed at all.
If it slows a little increase compensation.
If it speeds up at all decrease compensation.
Test on steep ramp with level ground in front of it.

Anything is possible. Hence the above. Only one way to find out for sure.

Its important to understand that the motor compensation setting is a motor electrical impedance setting designed to compensate exactly for load. It doesent only affect ramps but everything. It must be set correctly. Especially if wrong. By doing the above.
It is NOT a user setting designed to control how smooth a chair feels. There are other setting that can do this without setting compensation incorrectly.

HERES what PG say:
IGNORE THE BLUE unless you can measure that accurately.

Compensation matches the Power Module to the motors used on the wheelchair. This is necessary to achieve optimal performance and control.

PGDT recommend this value is initially set to 70% of the total resistance of the motor’s armature, and all the connectors and cables between the motor and the Power Module motor output. Motor manufacturers should be able to supply a figure the motor’s armature resistance and typical connector and cables may be around 40mOhm.

Example: The motor has a specified armature resistance of 100mOhms, and cables and connectors between the motor and the Power Module are estimated to be 40mOhm. This gives a total value of 140mOhm. The value of Compensation should therefore be set to 70% of 140mOhm = 100mOhm.
Once this value has been programmed, some drive testing should be carried out.


Then drive the wheelchair towards a gradient at a very low speed, perhaps 10%. There should be no reduction in speed as the wheelchair climbs the gradient. If the speed drops or the wheelchair stops, then the value of Compensation may be too low and needs to be increased.

As a final check, drive the wheelchair up a gradient at full speed and release the joystick. The wheelchair should come to a smooth, complete stop and should not rollback before the brakes are applied. If the wheelchair does roll-back, then try increasing the value of Compensation slightly. If the wheelchair appears to drive slightly up the gradient before the brakes are applied, then the value of Compensation should be reduced slightly.


WARNING:

These tests should be conducted in an open space and a restraining device such as a set belt should always be used. PGDT accepts no liability for losses of any kind arising from failure to comply with this condition.

The wheelchair manufacturer is responsible for ensuring that the value of Compensation is correctly set for the motors being used on the wheelchair. This is particularly important if replacement motors are being sent out to upgrade a wheelchair already in the field. Failure to comply with this requirement may result in poor control characteristics, which in extreme instances can make a wheelchair uncontrollable and potentially unsafe. PGDT accepts no liability for losses of any kind arising from failure to comply with this condition.

The wheelchair manufacturer is responsible for always ensuring that any replacement motors supplied as spare parts are fully compatible with the originals that the system was programmed to match. Failure to comply with this requirement may result in poor control characteristics, which in extreme instances can make a wheelchair uncontrollable and potentially unsafe. PGDT accepts no liability for losses of any kind arising from failure to comply with this condition.

A control system must not be moved from one wheelchair type to another without first ensuring that the system is correctly programmed for the wheelchair it is intended to fit it to. Even if control systems have the same PGDT part number, they may not be programmed the same. Failure to ensure the system is correctly programmed for the wheelchair may result in a hazardous condition. PGDT accepts no liability for losses of any kind arising from failure to comply with this condition.

[hotwheels_75]

the main issue is that I don't have a programmer and can't change anything myself. Well I do have a programmer but it's not compatible with this new chair. I didn't find the Aviva appealing at all. Same with the bounder's and I'm not sure how available they are where I am. There's really only two medical equipment dealers left that I'm aware of and I think it's become a competition of which one sucks more.I guess I just have to try it out and hope for the best,my hopes are not high.... They are currently laying in the dirt. This rep is a moron.

hotwheels_75, what issues are you having with with R-Trak?

I have the Aviva RX20 and I would not recommend it unless you do this fix from day one https://www.wheelchairdriver.com/board/ ... 60#p207949
Otherwise it steers like garbage when you load up casters going up/down ramps. After doing the fix it steers fine. I also know a person that put less than 200 miles on hers Aviva and both axle bearings gone bad. Makes grinding/snapping noises. I put 60 miles on mine and so far its fine.

As for another electronics option besides R-Net it is Dynamic Linx. The Dealer dongle is available and with patched software you get OEM level access. You can set global speeds, compensation, brakes voltage, inhibits, etc...

Is Bounder not available in Canada? https://wheelchairs.com/
https://wheelchairs.com/resources/pdf/b ... ochure.pdf

[Burgerman]

I long ago stopped being reliant on fools. I buy new chairs with serious discount. I buy chairs with less than 3 hours on them for 1/4 the original price from eBay. I allowed the wheelchair services to supply one TO MY SPEC. And I rebuild and improve my existing ones to better than new spec.

I also bought 4 or 5 complete R-Net 120 Amps systems, complete with seating, and cables, high end joystcks all either unused or actually brand new CHEAP!

I will never buy any chair that isnt R-net as thats basically the lst man standing. The rest are now all locked down and its even getting harder to get R-Net programmers.
Likewise I wont buy anything that isnt 4 pole, rear drive, and that I can get parts for.

You can either do the same while its just still possible, or be screwed by the system. But thats how its got!