Where to find PGDT programmer software

[Burgerman]

because their controllers are running a different algorithym than rear wheel drive chairs

All it does is reduce steering sensitivity as you increase speed.

FORGET programming or controllers. Think physics. Anything with the C of G behind the Centre of Pressure is naturally unstable. The vehicle WANTS to spin around and go backwards. Given enough speed, it will do so even if the drive wheels are on a SOLID axle and have to rotate together as a pair. The tyres will lose the fight, and it will swap ends.

No programming can fix the physics. Its the same with an aircraft.

Pitch stability (up/down) requires that the C of G is in front of the Centre of aerodynamic pressure. Or nose heavy if you prefer.

If it is, then a climb or dive is automatically CORRECTED. Or a naturally stable configuration. Like a rear drive powerchair.

If its in the SAME position, (CoG + CoP) then it becomes neutrally stable. As in it goes exactly where pointed but does not auto correct any pitch change. This is where most aerobatic planes are configured. Point it downwards and it will continue, without correcting into the ground in a straight line. This is a Segway, or mid drive chair.

However if C of G is even a tiny bit behind centre of pressure, the aircraft becomes violently unstable. And minute pitch change is amplified. It becomes un-flyable and crashes. This is your front drive chair.

NO amount of rigging the control system on your powerchair can defeat the actual physics. It can disguise it up to a point. But in the background you are pushing a rope - like the Indian rope trick.

[falco peregrinus]

All it does is reduce steering sensitivity as you increase speed

Yet again, thank you Burgerman. That makes sense. And it gives me a theoretical basis to justify experimenting with Front Drive Rate on my Jazzy, because that is exactly what is happening now, even after programming the chair in accordance with all your other suggestions. Clearly what I want - greater responsiveness at full speed - can be achieved by reducing Front Drive Rate. And probably further than the 10 point reduction to 70 that I was thinking of doing. Your explanation of it explains why the value is a percentage. I'm definitely going to play with Front Drive Rate now. I'm sure it needs reducing, because when I increased it to 100, the chair became even more unresponsive than it was before I gave up on the dealers and reprogrammed it myself in accordance with your other suggestions.
Thank you once again!
Falco

[Burgerman]

Turn front drive rate off. Tell it its rear drive. It will be fine.

Its a disguise to make front drive seem more stable. It does so by removing your control...

The other thing is battery voltage, and how much the controller leaves in reserve when you are at full speed. If it is already at 24v, then there's no extra left for turning. So it can only slow one wheel. Most systems leave about 10 percent in reserve. Hence 22v. in a straight line. Or say 90 percent is "full" speed. Batt weak? Less in reserve...

[falco peregrinus]

Burgerman writes:

All it does is reduce steering sensitivity as you increase speed

and suggests

Turn front drive rate off. Tell it its rear drive. It will be fine.

But after today's experience, I think there must be more to Front Wheel Drive Rate than that. The value for it on my VSI on my Jazzy, when I first got it, was 80. I tried setting it to 100, and within 30 feet I was turning around and heading back to the laptop to change it back again to 80 - at 100 the driveability was zilch and the responsiveness was 0. The chair was behaving even worse than when I first got it, before I reprogrammed it!
And today I tried setting it to 50, and again, within 30 feet I had ripped out the laptop again and was reprogramming it back to 80. At 50, just as at 100, responsiveness was terrible and driveability was zilch. But at 80 it's good. Not perfect, but good. At 80 there's a little too much movement in the joystick before you get a change in direction when driving at top speed, but it's not so much that I can't live with it if I can't find a way to reduce it.
The only information I can find, anywhere, on Front Wheel Drive Rate is in a VR2 Technical Manual (SK77898/4). It says:

7.3 FRONT WHEEL DRIVE RATE
Front Wheel Drive Rate adjusts the driving characteristics of the VR2 to suit a wide range of front wheel driven wheelchairs.
Adjustable between 1 and 100 in steps of 1.
Increasing this value means that the VR2's software is more suitable for higher speed front wheel drive wheelchairs.

which really isn't particularly informative. If anyone has a better, more meaningful description of what Front Wheel Drive Rate is, or knowledge of a better way to set it optimally for a particular chair other than trial and error, please post it. Does anyone have any experience with Front Wheel Drive Rate that they can pass on? Does anyone know what Front Wheel Drive Rate is set to on their chair? (It's a PGDT controller setting.)
Falco.

[woodygb]

It's no more useful than what you've found ...but the "HELP" files in the Programmer software also lists Front Wheel Drive Rate.

e.g. NewVSI

Front Wheel Drive Rate


Front Wheel Drive Rate adjusts the driving characteristics of the newVSI to suit a wide range of front wheel drive wheelchairs. Adjustable between 1 and 100 in steps of 1.

Increasing this value means that the newVSI's software is more suitable for higher speed front wheel drive wheelchairs.

VR2

Front Wheel Drive Rate

Adjusts the operation of the specialist software for Front Wheel Drive Wheelchairs.

The programmable range is 0% to 100%. If set to 0%, then conventional rear wheel drive control is always applied. The higher the value selected the more pronounced the impact of either front wheel drive algorithm. A higher value may be suitable for faster front wheel drive wheelchairs.

[falco peregrinus]

The higher the value selected the more pronounced the impact of either front wheel drive algorithm.

Thanks Woody. I thought I'd read somewhere that there was a different algorithym used for front wheel drive chairs. Couldn't remember where. The memory isn't what it used to be anymore, unfortunately.
Thanks for looking it up for me.
Falco

[falco peregrinus]

Woody, I'm contemplating making up a lead to plug into my VSI and connect to my multimeter so I can check battery voltage every now and then while I'm using the chair. The only info I can find on VSI XLR pinouts anywhere is in your diagram of how to make up an interface cable. Am I correct in thinking that if I connect the multimeter positive to pin 1 of the XLR connector and the multimeter negative to pin 2 of the XLR connector, I will be able to monitor battery voltage live while I use the chair?
Falco

[woodygb]

[falco peregrinus]

Thanks Woody.
Falco.

[Burgerman]

Your meter will tell you if its the correct way around. I just shove the probes in...

See viewtopic.php?f=2&t=3582

If your meter cant update at high speed - and most only do 1 or 2 updates a second - you may not see how low it goes on hard acceleration or when turning on soft ground etc.

Or fit an Anderson connector to the chair. Or do this: http://www.wheelchairdriver.com/wheelch ... ectors.htm

Or http://www.wheelchairdriver.com/faster- ... arging.htm

That makes a much better charging connector (thicker cables, fast charger capable, can run accessories, inverters, etc)

While you are at it! Your batteries will love you for it.

[falco peregrinus]

In the absence of any information on the PGDT parameter Front Wheel Drive Rate that would provide a structured, logical approach to setting Front Wheel Drive Rate on my Jazzy, I resorted today to trial-and-error testing.
The FWDR was set to 80% on the VSI when I got it. As I previously reported, at both 100 and at 50 the chair behaviour was so bad that I reverted back to 80 almost immediately after the change.
Today I took a more planned approach, and went to a quite, rarely-used bike path in a local park where I could test the FWDR in ideal conditions. To make a long story short, after testing I concluded that 80% was the best possible FWDR value for my Jazzy, so it is now back where it was when I got it. Here are the results:
At 80%, there was a good 1/2 inch slop in the joystick at full speed. Ie, I could jiggle it and no change of direction resulted. (I would have liked to reduce that a little - but it seems I can not.)
70% was noticeably a little worse than 80% in responsiveness.
90% produced greater slop than 80, but was unsatisfactory in a different way than 70. The behaviour at 70% left me without confidence in my ability to control the chair. It was stressful. 90% wasn't stressful - it just had greater slop than at 80.
75% wasn't quite as good as 80%
78% was very similar to 80%. Perhaps not quite as good as 80%, but perhaps no different to 80%.
85% was more vague than 80%.
Conclusions: 80% is the best possible. So I put FWDR back to 80 and called the job done.
Perhaps this information may be useful to others with a mid or front wheel drive chair.
Falco

[falco peregrinus]

Perhaps I should refine my conclusions a little. I stated my conclusion as "80% is the best Front Wheel Drive Rate for my Jazzy" - but when one thinks about it, that statement is perhaps a little broader than my test results have demonstrated. All I have really shown is that 80% is the best Front Wheel Drive Rate for an old VSI controller for my Jazzy. And I mean old. PGDT don't even have a picture of my VSI on their website any more. Mine also includes the ability to control two actuators. Current model VSI and New VSI do not include the ability to control any actuators at all. My Jazzy is about eight years old now. Anyway, my point is that a Jazzy with a different controller, running a different front wheel drive algorithym, just might have a different optimal Front Wheel Drive Rate than that which is optimal on my Jazzy with it's old VSI.
Falco

[Burgerman]

The actual best front drive rate will depend on a few things.

How unstable it is, being the important one. So how far the actual centre of mass is behind a line drawn between drive wheels. If its 6 inches it will be TWICE as bad as if its 3 inches. Drastically changing its stability.

Motor torque/gearing (speed)

Impedance (how fast torque drops away as speed increases) and actual motor compensation amount set.

Total weight.

So will really need setting individually as people are different shapes and weights, and chairs laid out and programmed differently. Which as usual is a good reason that the programming tools should be available for all of us as required. And not kept under lock and key.

[falco peregrinus]

I was hoping to find an equation listing all the variables known to affect it, and calculate the theoretical ideal - but I didn't do any good looking for it. If such a thing exists, it doesn't seem to have ever been put up on the internet - or if it has, then Google has never found it. It would have been very interesting and informative to have studied the equation and seen the magnitude and nature of the relationships between the different influences/ variables. Trial and error, as a testing method, leaves a lot to be desired. For example, the instability at less than 80% was different, in a way for which I find it difficult to find words to describe, than the instability at greater than 80%. (And "instability" probably isn't really the best word to describe it anyway.) It would have been very interesting to have had an equation that could explain that. And I could feel little difference between 78% and 80% - but was that simply because I, as a human being, was insufficiently sensitive to the differences to detect them? An equation would have told me that. Without an equation, I'm forced to the line of thought "well, I couldn't detect any noticeable difference, but maybe the manufacturer had a reason to choose 80 over 78, so I'll stick to the value the manufacturer chose."
Falco.

[Burgerman]

but was that simply because I, as a human being, was insufficiently sensitive to the differences to detect them?

Theres no "correct" setting. All you are doing is trying to 'hide' the naturally unstable configuration by dulling steering response through either delays (accelerations / decelerations) or reducing sensitivity.

So the "correct" setting is the compromise that a specific user is happiest with. So 78 percent feels the same as 80? Then use either! That's what its for. So even if you had a spread sheet with all the parameters that affect response - there is no "correct" setting.

[ex-Gooserider]

Also there may be other parameters that would impact the best setting if you changed them - some controllers have "dead band" settings that control how much stick wiggle it takes before the chair responds. BM probably wants a really small deadband as he has good control function. A person with poor control or spasticity might need / want more... There are also turning rate settings, and so on... Changing any of these might impact how sensitive your stick is, which will change the optimal FDR setting.

Playing w/ programming tends to be an iterative process - change one item then see how it affects other ones, and round and round you go...

ex-Gooserider

[Rousie]

Been watching this topic for some time, but was wondering if anyone has the modified tag file for the S-Drive? I have dealer-only version, and would like the options of OEM spec if possible!

Thanks all!

[woodygb]

Tag files ...Here you go.

http://support.pgdt.com/Remote-Service- ... mmers.aspx

[Rousie]

Does anyone have a new location of the OEM Spec Programming software? Tried the link in the post before, but it's exceeded the bandwidth... If anyone can supply it, i can host the files without any restrictions...

[woodygb]

What bandwidth is exceeded?

The pgdt link that I posted works fine for me .

[woodygb]

What version dealer level software do you have?

[Rousie]

Hi mate, 11.3.0 is the version i have, also 10.0 i think too!

[woodygb]

Download the pgdt software link that I gave above.

The C level tag files that it gives you just want renaming and putting into the dealer level.

eg.

S-Drive 130 Iss C-8.0.16
becomes and replaces
S-Drive 130 Iss A-11.3.0

[Rousie]

Just done the above, but when opened, it still says i have dealer access A... Not actually connected it up yet. but thought i would ask first!

[woodygb]

The Dealer blurb stays the same..... BUT the level of parameters that you can access changes.

Let me know how you get on.

[Rousie]

You're right, it's opened up a whole new world! GREAT...

Now, how do i get the cable to work with Powerchairs? I have a genuine PGDT cable for scooters, and had the idea that i could buy a female P4 Molex connector, some wire, and a 3 Pin Neutrik XLR to be able to convert it, but no idea if this would work or if i need any more parts?

Thanks for your help.

[woodygb]

Just putting a neutrik plug on the end of the scooter lead doesn't work...I did briefly try that myself..

It would be easier to just make the USB lead.

I will however revisit ( sometime ) the Scooter - Powerchair conversion adapter.

[Rousie]

Could you point me in the direction of making my own?

[woodygb]

Any radio programming cable ( KPG Baofeng etc ) seem to work with the addition of the diode.

There appears to be NO SET colour for the wires ...the wire colours seem to vary depending on the whim of the Chinese supplier of the cable.

Popping the case is the only way to be absolutely sure.... you should however be able to identify the earth wire using a multimeter and check continuity between the metal USB housing and the various wires that you have once the plug is cut off.

You then have a 50-50 chance of getting the diode in the correct wire. ... NO harm will become anything if you have the TX /RX the wrong way around.

[Rousie]

Excellent! i'd imagine ebay is full of these cables, but to save me a little time (and reading) could you point one out to me? Also the relevant diode?

I more than likely have all the parts required, but finding them is another story.

Any further help would be appreciated.