Programming Otto Bock C2000

[Burgerman]

Quite obviously, it has no other way to steer.

Tank steering works in the absolute opposite sense. You cant mix the two.

If it has tank steer on the drive motors, and you use only this, then the "casters" will not caster! They have no trail, they are symetrical, wrong geometry.

[FelipeOliveira]

Quite obviously, it has no other way to steer.

Tank steering works in the absolute opposite sense. You cant mix the two.

If it has tank steer on the drive motors, and you use only this, then the "casters" will not caster! They have no trail, they are symetrical, wrong geometry.

Good morning BM!

I managed to disable the servos.

And it happens exactly as you said, "IMPOSSIBLE TO TURN".

But as expected, I used the Ottobock B400 forks. I removed the axles and replaced them with machined ones of a compatible size.

But unfortunately I made a mistake, paying attention to the wheel diameter. This caused it to hit the chassis... but I'm already taking care of correcting that.

But to test it, I put on 7" Jazzy wheels. And it worked, it turned easily...

Now I'm having a little difficulty configuring it. It's very sensitive, very difficult to drive in a straight line...

And since you have a high level of knowledge, if possible, could you guide me on how to adjust the parameters in the way you believe is most correct?

[Burgerman]

1. It has 2 drive motors?
2. these are controlled SEPERATELY via two seperate channels?
3. this has 4 pole motors?
4. how did you disable the servos, in programming. Can you describe?
5. can you send me a copy of your settings file?
6. Presume R-Net?
7. do you have normal hands, good control skills?
8. correct joystick position so that your palm sits alongside the joystick pod and your fingers and thumb control the joystick?
9. is this now FRONT DRIVE and free to rotate casters on the rear?
10. does it have a GYRO and is that an R-Net one?
11. is your power module a normal 120A per channel with tank steer algorythm?

OK if its front drive and has no gyro it will be almost impossible to go in a straight line. Physics tells it that the CASTERS want to be in the front. It will attempt to turn around and face caster wheel first at all times. This gets worse as the speed increases. You cannot defeat physics. So in an attempt to do so, front drive chairs need a gyro module that attempts to correct this behaviour. But in doing so it needs large chunks of motor steer power much of the time, and so it "steals" this from the system and has a higher priority than the joystick. So once programmed to steer correctly then you feel that and its unpleasant. Thats why I only use rear drive chairs.

If yours is already rear drive and front casters than its probably just a programming issue.

SEND ME your settings file.
Video the problem.

I wait!

[Burgerman]

Its not r-net is it...

Answer the questions anyway!
And show a video of the problem. Because I dont know what "too sensitive" actually means.

[FelipeOliveira]

Its not r-net is it...

Answer the questions anyway!
And show a video of the problem. Because I dont know what "too sensitive" actually means.

https://vimeo.com/1158679883

It's very difficult to ride in a straight line, and any slip-up makes the rear end spin out, lol.

If you want, I can send you the original and current settings.

[Burgerman]

Says "couldnt find that video" ?

If its spinning out and trying to swap ends then that just physics. Front drive rear caster is unstable. It will drive great in reverse.

Yes send profile of before and after.

[FelipeOliveira]

Says "couldnt find that video" ?

If its spinning out and trying to swap ends then that just physics. Front drive rear caster is unstable. It will drive great in reverse.

Yes send profile of before and after.

https://drive.google.com/drive/folders/ ... hs8-OOHAlK

[Burgerman]

OK.

That is EXACTLY what I would expect to happen. That is because the mass (centre of mass, centre of gravity) and you, are all behind the drive wheels. That is quite literally physics in action. It creates an unstable chair. So any small turn is automatically increased/accelerated. Which then causes it to accelerate into an even tighter turn. And then again and you spin. The chair wants to go backwards.

Drive it in reverse and it will go straight...

If you take a manual push wheelchair. and then push it and release it, it will travel away in a straight line.
If you take a manual push wheelchair, and turn it around so its bigwheels are in the front and then push it away backwards, it will do EXACTLY what your chair does.

This is why I never ever want a front drive wheelchair. Here are your options:

1. Turn the seat around so the drive wheels are in the rear and the casters at the front! A rear drive chair. Now it will drive straight, and be stable.
If you dont want that:
2. You need to fit a GYRO like this: https://industrial.curtisswright.com/en ... yro-module
That will DETECT when the chair begins to swing out and use the motor power to correct it before it gets bad enough to feel. The problem is that while it works, with careful programming it feels horrible. You can feel that its trying to take control every time you do any sharp turn.

Of course you will need to use the same brand as your control system.

Personally I would junk the ENABLE 50?? and just fit 120A R-Net. And an R-Net gyro.

What is your MOTOR COMPENSATION set to? That also aids in preventing the chair being unstable (a little).
And you should set TURN ACCELERATION. MINIMUM TURN ACCELERATION. TURN DECELERATION. MINIMUM TURN DECELERATION (ALL 4) to 100.
Then you should set TURN SPEED to a low setting. To start with. And MINIMUM TURN SPEED ALSO TTO A LOW SETTING TOO.

GRADUALLY increase Motor Load Compensation in small steps at a time like 5mOhm. Or the chair can become dangerous and run away and be unstoppable.

Does that help?

[FelipeOliveira]

OK.

That is EXACTLY what I would expect to happen. That is because the mass (centre of mass, centre of gravity) and you, are all behind the drive wheels. That is quite literally physics in action. It creates an unstable chair. So any small turn is automatically increased/accelerated. Which then causes it to accelerate into an even tighter turn. And then again and you spin. The chair wants to go backwards.

Drive it in reverse and it will go straight...

If you take a manual push wheelchair. and then push it and release it, it will travel away in a straight line.
If you take a manual push wheelchair, and turn it around so its bigwheels are in the front and then push it away backwards, it will do EXACTLY what your chair does.

This is why I never ever want a front drive wheelchair. Here are your options:

1. Turn the seat around so the drive wheels are in the rear and the casters at the front! A rear drive chair. Now it will drive straight, and be stable.
If you dont want that:
2. You need to fit a GYRO like this: https://industrial.curtisswright.com/en ... yro-module
That will DETECT when the chair begins to swing out and use the motor power to correct it before it gets bad enough to feel. The problem is that while it works, with careful programming it feels horrible. You can feel that its trying to take control every time you do any sharp turn.

Of course you will need to use the same brand as your control system.

Personally I would junk the ENABLE 50?? and just fit 120A R-Net. And an R-Net gyro.

What is your MOTOR COMPENSATION set to? That also aids in preventing the chair being unstable (a little).
And you should set TURN ACCELERATION. MINIMUM TURN ACCELERATION. TURN DECELERATION. MINIMUM TURN DECELERATION (ALL 4) to 100.
Then you should set TURN SPEED to a low setting. To start with. And MINIMUM TURN SPEED ALSO TTO A LOW SETTING TOO.

GRADUALLY increase Motor Load Compensation in small steps at a time like 5mOhm. Or the chair can become dangerous and run away and be unstoppable.

Does that help?

Hello BM,

Of course it helps, that's why I asked you directly because I knew you would respond with valuable details and a lot of knowledge.
As soon as it arrives at the service center, I'll send you the settings. What I'd also like to change, and haven't found how to do, is the speed of the Stand Up function. I'll send the information later today. Thank you for your attention.

[Burgerman]

I might not be able to help.
But can have a look. You either need a gyro, or turn the seat around 180 degrees so its going the right way...

Front wheel drive is a (the) problem.

http://www.wheelchairdriver.com/gopro/unstable.mp4

It's very difficult to ride in a straight line, and any slip-up makes the rear end spin out, lol.

FelipeOliveira

[FelipeOliveira]

I might not be able to help.
But can have a look. You either need a gyro, or turn the seat around 180 degrees so its going the right way...

Front wheel drive is a (the) problem.

http://www.wheelchairdriver.com/gopro/unstable.mp4

It's very difficult to ride in a straight line, and any slip-up makes the rear end spin out, lol.

FelipeOliveira

Good evening BM

I JUST ADDED THE CONFIGURATION INFORMATION

Initial with Servos and Current without Servos

“CPF” and “XLS”

Inside the same shared DRIVE folder

https://drive.google.com/drive/folders/ ... nr0Y5IDj_M

Regarding your suggestion to invert the seat to make it Rear-Wheel Drive, honestly, I looked… looked. And I couldn't imagine how lol

[Burgerman]

OK.
I took a look.
You have 3 big seperate problems. EACH one will cause huge problems on their own.
1. Front drive NO GYRO.
2. Turn programming settings (and possible compensation settings) that are full HOVERCRAFT. Its not possible to have control that way.
3. Bad hand joystick skills (not your fault) and joystick in the wrong position making it impossible to hold the pod correctly which you will need to do once the programming is fixed..

That is EXACTLY what I would expect to happen. That is because the mass (centre of mass, centre of gravity) and you, are all behind the drive wheels. That is quite literally physics in action. It creates an unstable chair. So any small turn is automatically increased/accelerated. Which then causes it to accelerate into an even tighter turn. And then again and you spin. The chair wants to go backwards.

Drive it in reverse and it will go straight...

If you take a manual push wheelchair. and then push it and release it, it will travel away in a straight line.
If you take a manual push wheelchair, and turn it around so its bigwheels are in the front and then push it away backwards, it will do EXACTLY what your chair does.

This is why I never ever want a front drive wheelchair. Here are your options:

1. Turn the seat around so the drive wheels are in the rear and the casters at the front! A rear drive chair. Now it will drive straight, and be stable.
If you dont want that:
2. You need to fit a GYRO like this: https://industrial.curtisswright.com/en ... yro-module
That will DETECT when the chair begins to swing out and use the motor power to correct it before it gets bad enough to feel. The problem is that while it works, with careful programming it feels horrible. You can feel that its trying to take control every time you do any sharp turn.

Without a gyro, its never going to work...

Personally I would junk the ENABLE 50?? and just fit 120A R-Net. And an R-Net gyro.

Because I understand R-net and can easily configure it. Because thats going to be essential too. Unless you can find a gyro for a enable 50 curtiss system.

What is your MOTOR COMPENSATION set to? That also aids in preventing the chair being unstable (a little).

You MUST set this correctly, and you CANNOT do that with hovercraft steering settings. So do the following!!!

And you should set TURN ACCELERATION. MINIMUM TURN ACCELERATION. TURN DECELERATION. MINIMUM TURN DECELERATION (ALL 4) to 100.
Then you should set TURN SPEED to a low setting. To start with. And MINIMUM TURN SPEED ALSO TTO A LOW SETTING TOO.

THEN

GRADUALLY increase Motor Load Compensation in small steps at a time like 5mOhm. Or the chair can become dangerous and run away and be unstoppable.

That is the ONLY solution, and your turn accel and deceleration settings would make even a rear drive chair unusabe too. But this is a whole diferent issue. Because once you do the above, you have the wrong hands, wrong joystick position to take control in the way you need to to make that chair go straight anyway...

Watch and read this thread carefully!!!
https://www.wheelchairdriver.com/board/ ... =2&t=12707

[FelipeOliveira]

Good evening.
Thank you very much for the quick reply!!!
I'll read the indicated topic now, but first...
I just remembered that some time ago, I received some Paragolfers assembled by PBT (PowerBasetech) Mr. Christian, and the Paragolfers work with front-wheel drive, and one of them used the EnAble50, and I don't recall seeing anything besides the power module. I was wondering how it was configured... at the moment I have a Paragolfer here, but with Rnet and it also doesn't have anything besides the...…

This link is for the Paragolfer Motion X4 with Rnet.

https://youtu.be/_YvaHzv5Big?si=wx6hHXrv7d27FI_8

[Burgerman]

It has much of the same issues that yours does. Looking at the way it moves.

But a combination of correct motor compensation and the way the steering programming is configured, helps to make it more controllable. But also the front drive wheels are wider apart and so the rear is kept more under control.

And in R-Net theres are whats known as stability algorythms which use motor compensation to sense the rear swing and auo matically correct it based on motor current changing. They also have an algorythm designed to slow the chair or limit its wheel acceleration as you exit a turn and more.

But the only way to make it properly stable is a gyro module. Or make it rear drive. Set your reverse speed to say 80%. Now try driving backwards. You will find that it is totally stable and wants to go straight. You now need to force it to turn.

[Burgerman]

As well as the normal DRIVING controls, that need to be set correctly. R-net has a few additional settings that work independently to try and make a front drive chair usable.

There are:

1. FRONT WHEEL DRIVE SETTINGS: which use a different algo to try and make a front drive more controllable. And change the shape of the joystick "gate" electronically and other things. No module needed.

2. ADVANCED ELECTRONIC STABILITY: which attempts to use an exadurated motor compensation setting on TURN (differential motor speed - measured as changes in current) to correct unwanted turn. No module needed.

3. ADVANCED STABILITY MODULE: which is a type of basic accelerometer that also tries to use motor power to correct unwanted turning. This is a tiny module.

4. GYRO: This is a RATE GYRO is a 1 inch square module that accurately measures the chairs angle and so can detect if the chair turns when uncomanded. And this then adds more or less power to the drive wheels to make it go straight. This is the only thing that really works at any kind of speed. Because the instability gets worse as you get faster at a high rate!

NON of the above will do anything useful is motor compensation is set too low. And will do some very scary stuff if its set too high. And the only way to set compensation properly is by "feel" or seat of pants. And that also requires CORRECT and real time turn settings as described several times already and good hand/joystick positioning and skills/dexterity.


This is why I say I would swap it to R-Net, and add a gyro, and then program it correctly.

But generally you would use 1, 2 and either 3 or 4.

However the real problem that all of these things are trying to address is that a front drive and rear caster powerchair is a wildly unstable platforM. Physics tells it that it must spin around and put the drive wheels at the back, casters in front. All of this complication is an attempt to defeat physics. Which even when properly configured, and with a gyro is only partly successful. Because it needs all the power the control system has to prevent spin out. That takes away USER control. And it feels horrid! And slows the chair at times.
Turn the seat around and you dont need any of it.

[Burgerman]

Or...

2 bus cables, a seating and lights module, and a 120A power module. £50.

A joystick £80 brand new, offer accepted.

Then you need a PROGRAMMER and an R-Net GYRO module.

[Burgerman]

This will make it go straight...
https://www.ebay.co.uk/itm/127279392935

ebay R-Net GYRO module. These sell for £40 to £120 on ebay.

120A power module, 25 dollars.
https://www.ebay.com/itm/157293949373
And 20 dollars
https://www.ebay.com/itm/157488441909

Programmers are problematic. 2 on ebay right now but they are more than the new price!
https://www.ebay.com/itm/168110555106