PINNED - Roboteq Controller - developing for powerchairs

[wilsonintexas]

Thanks for tegh update.

been watching a one year old try and turn and accelerate, he misses the turns as well.

more later.

double checking on the temp range my daughtger would likely be using her poutside chair in, she is in Alaska. I think that it may rule out batteries... wathcing the other thread on cold temp and shortened life cycles for batteries.

I was expecting shortened range, but not necessar.y shortened life cycle.. But that is another thread.

[Burgerman]

LiFePO4 batts last a very long time. 10 to 15 years expected If looked after.
No above 3.6v ever, no below 2.7v ever, no heavy current charge or discharge use, no cell imbalance. Stored at say 60 to 70 percent full when unused - not full, and in a cool place.

Basically the opposite to what you get with a BMS and dumb charger, in a small capacity low C rate pack, used hard... Do the opposite, use the biggest pack possible and as high C rate a pack as possible, no BMS and charge with a cell balancing charger. This way they should last forever and you get better performance as well as huge range or more speed.

LiPo batteries as we use for hobby stuff last a few months use only. If we store them for winter, the fridge is perfect. 2 Centigrade. This makes them survive till summer without swelling up or going high resistance. The cold makes them age slower. But we don't USE them when cold as they perform badly. At first. But as you use them (hard) in models they warm up, and end the flight quite toasty!

[Burgerman]

Just to clarify something.

It takes 4x the energy to reach 8mph compared to say a 4mph chair. It takes 4x this energy again to reach 16mph from 8mph. And the same is true of deceleration as well as stopping distances.

So if it takes say 1kwh to reach 4mph (it doesn't! Its just for the purposes of demonstration), then it also takes 4x this 1kwk = 4kwh to reach 8mph. And then 4x this = 16kwh to reach 16mph.

Conversely it takes 4x the distance to stop from 8mph than it does from 4mph.
And another 4x further to stop from 16mph. A total if 16 times as far. And this is quite scary. Requires responsible use.

The stopping (or control anticipation) requires you to cover some 16 times the distance required to stop a 4mph chair. You cant just "stop" in a few meters. Lets say 3 meters from 4mph. That will now be some 48 meters! Or a very long way in front. As such 16mph feels very fast. And requires some care and responsibility in use or you are likely to break your legs or someone else's. You also have 16x the kinetic energy if you hit something. The throttle goes both ways.

[wilsonintexas]

I was just on the roboteq web sire, looking for some information on controllers. They have a listing that SEGUL in france is using their hdc2450 controller in a wheel chair. I think that it is the same controller you are using (50 volt, 150 amp). I tried looking for some more info on it, since they are using a 50volt controller, i am guessing they are running mroe than 24 volts.

I did a few googles and did not find much more info on the chair.

[Burgerman]

Cant find anything. They will be having serious issues without lenny's complex script and current sensors!!!

[woodygb]

It might be SEGULA.

http://www.stabiload.net/medias/media/other/37/plaquette-uk-2014.pdf

PAGE 17

– Development of a highly innovative electric
wheelchair

[wilsonintexas]

I was hoping that since they were using a 50v controller, they were using some serious batteries and power. But could not find much.

[wilsonintexas]

correct segulA.... sorry about that.....


looks like thye did another 24 volt, 60ah 6mph wheel chair...... and they say that it was done with inlut from users..... I guess they were french users....

found a web site it looks like they are just launching it. This is a google translanion so you have to take a few liberties.

TOPICALITY CONTACTS
Products
Products> Whing


Whing, the path to independence
The Whing is the innovative electric wheelchair course by the users themselves. Whing has sophisticated basic features to meet a perfect customization of the chair for each user by combining the best comfort, the most suitable positioning and maximum performance

The seat of Whing is fully automated to support all body movements in comfort and safety.

2 years warranty
The Whing chair has a frame of 6-wheel independent suspension. This improves user comfort including pavers or during obstacle clearance of up to 7 cm.
An electronic system was developed to allow users to control all cylinders to 2 integrated modes:
Manual mode with possibility to control each cylinder independently
Automatic mode with the possibility of pre-program four positions chosen by the user in accordance with the purposes of compensation of the user.
Options

Kit Road
Custom tablet
Door respirator
Door backpack
Compatible different special cushions, seat elements
A series of remote display has been integrated to view the Whing management system with computer graphics in color, incorporating a decidedly attractive and environment control.

The chair uses batteries Whing new generation Lithium ion technology allows greater autonomy and a lifetime much larger than other chairs.
Available in white and customizable stickers on different topics
Personalize it to your taste by combining several colors.

Technical specifications Whing

Category: B (indoor & outdoor)
Lithium-ion battery: 25.2V / 60Ah
Engine: 2 x 400 watt
Battery life: 31 Km
Maximum speed: 10 km / h
Frame width: 63.5 cm
Length with pallet: 130 cm
Minimum length: 104 cm
Folder, hamstrings & armrests: Electric & offset
Turning radius: 70 cm
Seat width: 35 - 50 cm
Seat depth: 42 - 53 cm
Back height: 46/60 / 66cm
Height floor / seat: 41-79 cm
Tilt seat: 13 ° (Trendelenburg) - 15 ° (sloping)
Backrest angle: -80 to 0 °
Crossing: 7 cm
Lift & stander: Electric
Electronics: E-Whing
Fixing system: 4 attachment points
Suspension Front / Rear: yes
Maximum user weight: 120 kg
Empty weight: 167 kg
Society Welcome Products

will try to get some of the pictures in a few minutes.
this is one picture.



the basic web site is: (needed to have google translate)
http://www.drk-mobility.com/societe

the chair is called wht whing

[Burgerman]

60Ah x 24v = 1440 watt hours. And it uses a BMS... Expect the battery to last either not long at all or about 3 years if you are lucky. Misses out on the huge efficiency gain of around 100 percent by using double the voltage. No idea about drivability, and the code it must run. Hopefully not roboteqs stock tank steer built in one as its unusable.

My batt is 3240 watt hours for eg. 2.5 times better, 2.5x less hard worked. And at 45v around 90 to 100 percent more efficient.
Wills is I cell more voltage, and 45Ah giving about 2150 watt hours. Less - but its also brushless so gains efficiency back.

They have done exactly as I expect all wheelchair manufacturers will do. Lithium for the sake of it (marketing) and totally missed the point and all the possible advantages they really can offer. It could have had 100 to120Ah of LiFePO4 in the space its lead batteries came out of. That setup will offer very little over lead even if reliable. They just fitted lithium "lead replacement" bricks... The equivalent to fitting 35Ah lead batteries to an 8mph wheelchair.

[wilsonintexas]

I think that the max speed is 6.2 mph not even 8 mph.

oh well.

[LROBBINS]

John,

It's been a long time since you've said anything about the "lag on initial acceleration - runaway acceleration" problem and I'm wondering what the situation is. If I remember correctly, your last comments were that you thought that adjusting motor compensation might resolve the problem, but you haven't said whether it did. So how about an update on the driveability experience?

I don't think that you should be settling for "good enough" so if there are still any problems I'd like to get back to diagnosing them and then working on the script as needed. As well as refining the code, or adding functionality if needed, it may also be possible to simplify it - the shorter it is, the more responsive it can be. Some examples:

The script has separate acceleration and deceleration values for the left and right motors. I don't really think that this is needed, but is that your real world experience? (having one acceleration and one deceleration setting for both motors won't make the script any faster, just would be a bit neater).

I had added two parameters that can vary acceleration and deceleration, either positively or negatively, with motor current draw - that is AccelMotorComp and DecelMotorComp. Is this of any use at all? If they're not needed, getting rid of those calculations would make the script a tiny bit more nimble.

I had added AccelMixMode that can be sent to 1 to truncate accel/decel mixing at 0, or 2 to boost the opposite motor's accel/decel if one motor would be < 0. I suspect that this makes little difference, but mode 2 makes more sense to me (should be a wee bit more responsive in some situations), so if it doesn't make any difference I'd just get rid of the parameter and simplify the subroutine to always do the equivalent of AccelMixMode = 2.

I also have an ulterior motive for asking these things. I have the Programming-over-CAN node for the CANbus system done (writing a sort of user's manual at the moment). It lets one do initial calibration or re-calibration (even detects whether initial setup has been done) and adjust all parameters in all nodes with only one connection between PC and any CANbus jack, but I didn't yet include the Roboteq-specific parameters (accel/decel and motor resistance). Once we're pretty sure which of those are really useful, I'll modify the program so that those setting are handled over the same one PC connection. Roborun would only be needed for setting up the profile to match one's wiring and for Roboteq firmware updates.

Ciao,
Lenny

[Burgerman]

Since they have been shovelling mountains of corrosive salt on to the roads I have not been using it. Or rather not outdoors.

I don't think there is any real system delay, as such. It happens because have the acceleration programming backed right off at the moment compared to my PG Drives chairs to a large degree. So the initial instant urg, that lifts the wheels without moving more than 1 inch is gone. It builds more slowly.

In a slow 24v chair I have acc set to pretty much instant. So I jab the stick and it jumps. Hard acceleration. As it gets to 2mph acceleration (power and torque) drop away fast even at 100 percent pulse width. So it doesn't want to go crazy and accelerate like a dragster and spit me out. So I can gun it and acceleration tails away from that moment on as I reach terminal 6mph...

With double that voltage, and acceleration set likewise, yes it leaves instantly. No delay. But acceleration is limited only by the pulse-width. At 8 to 12 mph it will STILL accelerate just as hard as it did initially. To the point where it tries to deliver 45V x 150A x 2 = 13.5 kW... So the initial acceleration is too high from say 2mph onwards.

Its hard to explain. But with acceleration set to high, its fine initially from zero. Then you get rolling. But 3mm of stick will flip you at 10mph... Its a bit like a 300mph top fuel car with its 1 gear. Once they get rolling, and the tyres get some grip from the wing, they accelerate much harder and sometimes flip...

I suspect I need to make a few settings changes outside somewhere flat where I can do some proper testing as soon as the spring turns up. Indoors with acceleration turned up, but speed set low with the pot its fine. Its when you leave the wheelchair 6mph speeds and go fast that it becomes a bit strange. But I suspect that it just needs a few settings sorting out.

I don't want to get it covered in salt and crud yet though! I have 3 other chairs.

I suspect the real issue is this. Guesstimated at stall...
100A 24V mobility controller is making at stall 2x 100A x 24V @ 20 motor volts. 2000 Watts. 100% PULSEWIDTH
150A 45V Roboteq controller is making at stall 2x 150A x 45V @ 30 motor volts. 3000 Watts. 60% PULSE

This is OK...

At 3mph mobility controller delivering 50A @100% PULSE
At 3mph Roboteq controller delivering150A @ 70% PULSE

This is wild, 3x the acceleration...

At 6mph mobility controller 10A @100% PULSE and no longer accelerating.
At 6mph Roboteq controller 150A @ 80 PULSE (remembering that the acceleration may be even ahead of the chair due to current limiting)

This is flip city and accelerating like a dragster... Any time Amps exceed say 70A the front lifts, Torque = Amps...

Same at 10, 12 mph. Only after this does the torque and acceleration start to tail off towards a 15 / 16mph constant.

[LROBBINS]

Ok, if that's the problem, and I await better English weather for you to find out, it would be easy to program things so that base acceleration and deceleration decrease as speed increases. I'd think that two parameters would do it: at what motor output do you want accel to get "softer"? how "soft" do you want it to be at full power output? To do this we have to measure output power, not stick position, but we already retrieve the needed numbers in the MixAccel subroutine. Two more user settings and perhaps 3 lines of code would do the trick. If it is this, we get rid of AccelMotorComp and DecelMotorComp and associated calculations.
Ciao,
Lenny

[Burgerman]

That sounds like it would probably do it.

I need to test in warm, on grass, getting flipped out at speed because power keeps building fast even as you back off is scary, and quite worrying. This chair feels like its going 3x faster than you would expect!

[Irving]

Maybe you need to start a new category down at the Pod, Wheelchair drag racing

seriously tho, for testing maybe some longer/higher wheelie bars to catch you if it goes pear shaped!

[Burgerman]

The difference is 14kw capability at 9mph. It pretty much goes! Or wants to.

[Burgerman]

I am just fitting a 4 segment super cheap battery level meter.
Works from 4V to 50V

2 wires. Black / Red are power (4V to 50V brightness doesn't change) and 0V. Its bright.
3rd wire, Voltage sensor wire. This 0V to 50V.

It's very accurate. I tested it at 5V and 12V and 31V as that's as high as my power supply goes.
Its absolutely spot on and matches my calibrated fluke test meter. In the event it doesn't, there's a tiny pot on the rear that allows you to adjust it.

For my purposes, the power and sensor wire can be connected to the battery positive. And the neg to the neg.

Its tiny so will sit behind the pod.

This is all you need for lithium to know when to go home. I already have a low voltage flash LED from Lennys script. But its nice to see real time voltage during the day.

Lithium Ion Phosphate starts at 3.6V per cell, and drops to 3.3x fast. in a few hundred yards. It pretty much stays there most of the day so to get any idea of what's happening you really need 2 decimal places. I will check the actual voltages to .xx Volts as I discharge the battery with the Hyperion. And make a note. So I can see approx. where I am. At 3.0V per cell its about done though. So it should start at 44 to 46V. And fall to 42 volts most of the day. And when it drops faster to 40V then Its about 80 percent done.

[Irving]

not bad for £3.50-odd depending on LED colour (or £1.99 in blue from another supplier)

[Burgerman]

http://www.ebay.co.uk/itm/LED-Blue-Digi ... 1131954951

Cheaper = bigger. Digital Tube Size: 0.46"

This one I have is tiny. Note the AA battery. Its 0.36" tall numbers.

Mines only black because I sprayed it. I think will already has one?

[Williamclark77]

Yup. That's exactly what I've always been using for a battery gauge. Mine is in my joystick housing. I did put mine on a button so I could turn just it on/off. Too bright! It puts out a lot to be so tiny (that's what my ole lady says). I really see no need for anything else to monitor the battery's state of charge. I need to take a picture one day.

[Burgerman]

I tried, its so bright that it blows the green channel. So you underexpose by 3 stops to get the green LED, and the picture is black... So you use the flash. Terrible thing to photograph!

Tell me at what voltage do you decide what?

I realise you have 14S and I have 13S and I will do the math! So far I never went far enough in 3 days to bother my battery! Unlike the always dead lead... So I wasn't going to bother with any gauge. Just watch what went back in. One of my hyperions went bang. They do not like it if you connect a powerful battery like yours before the charger is powered up for at least a minute. It does something very fast to the Mosfets... That's 2 now down out of 5. Another one went a bit mad. They do get used a lot here though. And abused on massive batteries and thrown around.

And they don't make them any more. So I am going to look at the stupidly expensive Powerlab 8v2.


But there's a newer version of that coming out any minute so am hanging on... Its software is really hard work in comparison. And the obvious problem for you and me is that we will need to split charge as they only do 8S each... So need TWO of them. And have to do a bit of a rewire.

I would get an iCharger but the software is missing... Although you don't really need it. I like it! Also daft money.

[Williamclark77]

You'll have to take 2 or 3 pictures at different exposures and combine them. Either HDR software to combine or lay them on top of each other in Photoshop and erase bits. Time consuming.

The most I've taken out of my battery is 28ah. And that took about 10 HARD ROUGH miles over two days. Mine is 50.3 to 50.4 volts when taken off charge. It drops to 46.5v almost immediately and stays there until about 15 or 18 ah are removed. It then drops to 45.8 to 46.0v until 25 or so has been removed. It then drops a bit to 45.0 or so. That's as low as I've gotten it.

It does start dropping a good bit more under a hard load once I've pulled 15 or so ah out of it. Nothing bad though. It starts out dropping about 1 volt under a long heavy load, but recovers to 46.5v within a few seconds. As the battery gets 15 or so ah pulled out it will drop about 2 volts or so under a load and takes a bit longer to recover, but not much. Maybe 10 seconds.

Pure laziness or just testing is the only reason I'll get it lower. I don't charge it unless I'll be in it shortly so that it doesn't sit on full.

[Burgerman]

You realise that your LEAD chair hits 16 to 17 volts if you hit it hard? From about 25.5. So a 9 volt drop on 25v. That's about 30%!!! Much worse if a bit discharged. You still hit the same volts, but less amps because the controller "lets go" to keep it alive and protect the batteries.

Lead really is crap in comparison. What do you have 45Ah? 48v? You should get 3x the range of a brushed lead powered chair at least, maybe more.

Do you have a hobby style Watt Meter?
Connect it up, drive at 4, 6, 8, more MPH over a measured mile on the flat somewhere. And see what it uses. I did that with my phone. The GPS measures a true mile. Do it both ways.

Then you will know true range give or take a few percent.

https://www.youtube.com/watch?v=Lxv9Rozs774 Cheap, work well. Plug in temporarily. The lower your motor impedance and the higher the batter voltage the bigger the difference between motor and battery Amps. Total watts is the same. But you win by getting lots of torque with very few motor VOLTS.

[Williamclark77]

Nope. I don't have one. I had one of these hooked up for a while. Not exactly but looked the same.

http://www.ebay.com/itm/DC-0-120V-0-100 ... 2a4a57e9f9

Waste of time and effort. Per the instructions it has to be calibrated at several different amp levels. If I had the equipment to put it under a calibrated 1, 10, 25, 50, and 100 amp load to calibrate it to, I most likely wouldn't need the device. For measuring amps and ah it was worthless. For measuring several other things it was fine. Glad I ended up not needing such.

I hope to do some real testing when the weather permits.

[Irving]

Just ordered a couple, silly not to at that price.

[LROBBINS]

I too would order one or more of these voltmeters, but none of the dealers linked to in your messages will post to Italy. There were ca 600 items on ebay.com when I searched for voltage indicator, but none like these. If you come across a dealer who will ship to Italy, let me know. Ciao, Lenny

[Irving]

I too would order one or more of these voltmeters, but none of the dealers linked to in your messages will post to Italy. There were ca 600 items on ebay.com when I searched for voltage indicator, but none like these. If you come across a dealer who will ship to Italy, let me know. Ciao, Lenny

Lenny happy to order some and ship them to you... postage UK -> Italy 5 biz day untracked, £3.20!

[Burgerman]

I can do it too if you want. I have the green and the blue ones and will be ordering more. Better than red or yellow somehow.

EVERY powerchair charger needs one fitting, even stock ones. That extra digit is useful to see trends. Every powerchair and charger needs one! There's also one on my vans battery (inside the van).

Super accurate - esp once calibrated. And every power supply, or device needs one. About 16mA draw though. So needs a switch if you leave it on anything with a battery for more than a day or two.

[LROBBINS]

Here's an outline of how to use the Programmer node for the WheelchairCAN system. Unfortunately, by the time all the images were compressed enough to make it possible to attach the file, the text in the screen shots has become pretty hard to read. If you'd like a more readable copy let me know and I'll send it by e-mail.

I'd originally thought to make a fancy GUI specifically for this, but then decided to make my life easier by just using the Arduino IDE. It's not as pretty as what one could do with a GUI made specifically for this, but I think it's pretty workable.

Ciao,
Lenny

[Burgerman]

Very good. I think. But I don't understand it