Pride Mobility Accu-Trac reviews/comments?

[RRolf]

I am specing out a replacement power chair for my wife, and wondered what people have to say about the Pride/Quantum Accu-Trac option.
(nothing seems to have been posted on this site about it)
Is it worth the $600+ cost? How well does it handle slippage on wet grass, ice and snow?
My underderstanding is that it is primarily a $$ software option. Has anyone tried turning it on and off to see how significantly it improves steering?
Are there any down sides? Loss of range? Lower top speed?
(I can't see a speed for accutrac on the Q6000z spec sheet but Pride factory tells me 6 MPH and it uses the standard motors).

We get out a lot, and icy patches on our sidewalks (and poorly shoveled walks) present a bit of a challenge for her when the wheels slip.
We also do a lot of outdoor hiking, so something that makes her steering effort less challenging on dirt trails would be worth while IF IT WORKS.

Is the G-trac from Invacare better? At $1500 I expect it to handle ice patches well, but does it?

I am currently looking at the Quantum Q6000Z with 100A Q-Logic ctlr as the best compromise between ground clearance, size, price and performance.
And Pride is about the only brand carried around here.

And comments or suggestions welcomed.

Bob

[Burgerman]

All of the CLOSED LOOP systems that help you track including prides one, or some gyro based ones, have the same issues. They remove the "feel" or feedback.

You cant tell how much torque is being applied. This means you cant feel what's happening. I personally wouldn't want it as a gift. If however you are struggling with control or don't have normal joystick setup, or are using non proportional control systems, then it can be helpful. If you don't need it, avoid.

Also much more important, I wouldn't want any chair I could not program correctly. This basically means don't buy anything pride, as they keep all the tools away from the users. This has way more affect on steering than accutrack or whatever.

Is the G-trac from Invacare better? At $1500 I expect it to handle ice patches well, but does it?0

If a correctly programmed chair cant handle the ice, accutrac or any other gyro or closed loop wheel position system cant help you. If theres no grip, then nothing can help. And an automated system trying to keep you straight may be worse than not having one as it just tries to correct regardless of any wheel spinning. It doesn't understand ice!

[LROBBINS]

Tracking systems, as Burgerman said in a different way, do not improve traction. They improve the ease of tracking straight over uneven terrain. Not very useful for people with good joystick feel, but extremely useful for those using things like head switch arrays or sip-and-puff or any other non-proportional control. Same is true for a regular joystick if the user can't use it in proportional fashion. If you can drive reasonably well with a joystick, if your batteries and wiring are low resistance, and if motor compensation is adjusted to where it should be, close-loop tracking adds little or nothing.

Ciao,
Lenny

[Burgerman]

Only tested it once. Quite apart from adding little or nothing, it actually makes the thing very unpredictable and was hard to judge what was happening under the wheels.

It feels quite horrid.
And can be quite dangerous.
EG almost broke toes trying to gently open a stuck door with my feet as usual. Because it keeps adding torque as you move to "compensate" for resistance without you having to try. With a normal setup the chair will need more "stick" to move against an obstacle or slope etc. This is a form of terrain or force feedback. Mostly this is lacking in any automated enhanced tracking or closed loop control system.

They all work a little differently. Some use a wheel or motor position sensor, some use a solid state gyro. Some use both. They help some people with control difficulty or alternative controls to go straight or track accurately. But as Lenny says you don't need (or in fact want) this if you have normal joystick skills.