Magmotors, UK Supplier?

[Burgerman]

i am just wondering if those magmotors (www.robotmarketplace.com) are available anywhere in the UK. Fancy trying a set on my off road/indoor/outdoor chair! www.wheelchairdriver.com/images-life/powerchair.jpg

Because of carriage, damned UK customs ripping us off (they check EVERYTHING that ships from the US and charge additional charger on top of vat...) etc.

And a roboteq controller possibly. Also uk supplier? Need to see the software otions and other details. Want exponential, but no delays... Just like my rc planes and helis. And my ford granadas steering...

[JoeC]

Their website says they are temporarily out of stock, but some online sellers don't update their pages very well:

http://www.active-robots.com/products/m ... otor.shtml

You might have some luck giving them a call.

Oh, and it says that they do have the roboteq in stock:

http://www.active-robots.com/products/m ... oteq.shtml

Regarding the Roboteq, I think you'll be able to get exactly the response you're looking for, but you'll need to feed it an actual RC signal to get it. The guy using it here tried the analog input to start, and the programming options were far too coarse to hit the mark. He replaced the direct analog in with a link to an RC joystick, with a transmitter and receiver spaced several inches apart (using the same mode of fail safe operation that you describe), and has a much better time with it.

Looking at the user manual, it looks like the maximum ramp rate is from zero to full output in just under a tenth of a second- a little better than twice my measured results on the DX, and about ten times better than what I measured on the P&G Pilot+. I don't think you'll be disappointed.

[Burgerman]

Thanks. Not cheap then!

This is interesting. It can do true non delayed exponential, like my transmitter, with an analogue input rather than timed "accelerations" like powerchair controllers... No rc transmitter needed? Shape of curces programmable by pc etc just like my rc transmitter. Maybe I am looking at the wrong thing?

That alone makes this controller better than the dynamic or the p and g powrchair controllers, The inductive joysticks in the pods we already use can still be used with it too, with the analog 0 to 5v input, and radio control too without building my box of tricks!

http://www.active-robots.com/products/m ... manual.pdf

[JoeC]

This may be nitpicking, but the AX2550 does change its speed at a programmable acceleration rate. The fastest rate available is 18.5% change in 16 milliseconds, 0.085 second delay from the time you move the joystick to full and when full power is applied. P&G and Dynamic don't tell you their ramp rates, but I've measured them at 1 second for P&G, and a little better than 0.25 seconds for Dynamic.

Roboteq is almost 4x faster at ramping than the Dynamic DX (didn't check the DX2), which is a little better than 4X faster than the P&G. They have a section in the manual on setting the acceleration time- I didn't see any option to disable it for a hard start.

Too bad about the price- it looks like you're paying about 150 pounds more for the AX2550 than we would over here.

[Burgerman]

That ramp up info for dx compared to p and g is interesting. Are you sure its 1 second? Mines definitely got its front wheels in the air before I get the stick to full forwards! Thats much less than a second. But maybe so I never measured it. With the motor compensation set higher than "normal" it seems to fairly jump into action...

But that "ramp up" should be programmable. Plus the time taken to run the code of course. So it cant be instant.

As for cost its the same with everything. Thats why I imported my van from the US since it was half the price of a "proper" right hand drive one!

[JoeC]

I didn't touch the compensation on my P&G, so perhaps you're right that it could be better. What I did was measure the current at 100 hz, and plot each point to see the time it took to move from zero to its max of 80. It was a smooth straight line that starts at about 50/100s, and ends at about 150/100s.

pg80.jpg (57.29 KiB) Viewed 4035 times

There was no problem lifting the wheels with that controller once the seating position was correct.