Traction control for an M35 series.

[Heath_h49008]

So we all hate getting stuck, and lockers are wonderful, but 3 would add up to $1500 plus installation which in most cases would require pulling the axle.

But we do know that an open differential can deliver even torque if the side that spins has the brakes applied.

So we would need a speed sensor on both sides of the axle, and some way to modulate brake pressure side to side if the speed of one side exceeds the other by "x" amount. So a simple processor, two sensors, and a way of generating brake fluid pressure and sending it in a controlled manner to one side or the other is all we need.

The sensors could read off the wheel studs by drilling through the backing plate, or adding something to generate a signal on the hub... we have room to play with however we rigged it. The processor would be a scratch build with drivers for the ABS/Traction Control module. These are getting more common in the scrap yards, and as long as you paired it for one axle instead of trying to manage a whole vehicle stability system, the programming would be simple.

Honestly, with the right manufacturing behind it, it could be built cheap with one fluid line in, two out and power to run it. Oh, and you could add ABS at the same time with a software change if you sourced the right module.

I'm just throwing the idea out there in case anyone has any thoughts on how it could be done.

 

[patracy]

1. Anything you find in the junk yard will be 12v, ABS tends to use a sizeable amount of amperage too.
2. The sensors would work in theory, until the first time the drums get packed in mud/water/junk.
3. The wheels studs are on the hub, bolted to the drum, the studs wouldn't be visible to the hall effect sensor. Nor would six points be enough resolution. (Nor would the bolts holding the drum to the hub)
4. You'll have to re-plumb the entire system.
5. ABS actuators only handle two channels. The front and the rear. You've got three axles to control. You'll need another controller.
6. How much programming have you done? I'm starting to learn a little about GM ECM/TCM programming under a HPTuners interface. It's not all that simple. You'll need to understand the language the controller needs, address any interfacing issues that you might have to overcome if it's not canbus.
7. You're going to have to find something that can deal with the volumes needed for the wheel cylinders.
8. The actuator isn't a user serviceable item. You'll need to swap the rest of the vehicle to DOT 3/4. Otherwise I can see it getting gummed up.
9. You'll need a two channel MC, as well as a means to increase the pressure. (I'd question how fast the air packs can return fluid in the system you're thinking)
10. Didn't they try a "modernization" program on the deuce called the A3? I've seen more complaints out of overly complex systems.

It might be cheap thinking about the core components to make some system like this. But your cost to get something working will exceed $1500. Easily.

 

[swbradley1]

PA is pretty spot on with his comments but I will add one. In my mind the programming of a controller would be the easiest part. Since you are starting from scratch anyway I would use a simple microcontroller.

Doesn't Steve already have an ABS axle on his website?

http://differentialeng.com/TwoHalfTonMilitaryRockwell.htm

?????

 

[patracy]

PA is pretty spot on with his comments but I will add one. In my mind the programming of a controller would be the easiest part. Since you are starting from scratch anyway I would use a simple microcontroller.

Doesn't Steve already have an ABS axle on his website?

http://differentialeng.com/TwoHalfTonMilitaryRockwell.htm

?????

That wouldn't work in the fashion he's looking for since it pulls off from the drive gear.

 

[ivbeenrokd]

I like traction control on modern vehicles for std road driving but in an Offroad situation where I would want lockers I prefer to turn the traction control off every time (even if I don't have lockers). I think lockers would likely be easier, less expensive, and a better end result.

 

[swbradley1]

That wouldn't work in the fashion he's looking for since it pulls off from the drive gear.

Yes, but at least some of the engineering is already done, even if it is for both at the same time.

 

[Heath_h49008]

Patracy is correct... a better reluctor ring would be needed. It would have to be on the hub, which would be interesting given the hub flipping, but not insurmountable.

Mud and water doesn't bother standard ABS rings/sensor pairs, so this one wouldn't be any more vulnerable.

My programming has been CNC "G" coding for machines, C, C#, and the general WYSIWYG classwork they push in today's colleges. I'm no expert, but I can digitally whittle and not run the tool into the head most of the time.

As for the total upgrade required, I don't see that as a negative. The same issues exist for master cylinders... volume, hydraulic boosting vs saving the airpacks, etc.

More than $1500? The first one will be for certain. But if you already want better brakes the relative cost is cut, if you have a 12v circuit with a battery equalizer or 12v system, your costs are cut, and if you have power steering to power a hydroboost master... you get the idea.

I guess the real issue is to try to build it for one axle. A rear to keep it as simple as we can.

 

[patracy]

Patracy is correct... a better reluctor ring would be needed. It would have to be on the hub, which would be interesting given the hub flipping, but not insurmountable.

Mud and water doesn't bother standard ABS rings/sensor pairs, so this one wouldn't be any more vulnerable.

My programming has been CNC "G" coding for machines, C, C#, and the general WYSIWYG classwork they push in today's colleges. I'm no expert, but I can digitally whittle and not run the tool into the head most of the time.

As for the total upgrade required, I don't see that as a negative. The same issues exist for master cylinders... volume, hydraulic boosting vs saving the airpacks, etc.

More than $1500? The first one will be for certain. But if you already want better brakes the relative cost is cut, if you have a 12v circuit with a battery equalizer or 12v system, your costs are cut, and if you have power steering to power a hydroboost master... you get the idea.

I guess the real issue is to try to build it for one axle. A rear to keep it as simple as we can.

Mud doesn't bother reluctor rings? Umm, yeah, it can.

I understand that you can code your software. But you'll either need to find a very very simple ABS module that uses only signals, or a canbus module, then learn canbus.

$1500 even in a large/mass production will be hard to make. And you're going to eat at least $200 into that number just getting a 12V system on a deuce.

Maybe if you found a single channel module or used a standard automotive one at the rear axle (you'd have to tee their inputs) to run the rear. Perhaps you might get it to work.

Good luck with it though. I just personally think it's a lot of hassle for minimal gain.

 

[mudguppy]

Do we believe we can get a processor (to include hardware, firmware, and programing development) to do all this (6 wheel speed monitoring) for less than $1500 by itself?

you also need to add a pump separate of the braking system to provide braking pressure to any 1 - 3 spinning wheels.

while neat (modern, on par with high end off-road TCS systems), I still think you'll be money ahead even after installing 3 ARBs...

btw, I'm not against it by any means. Seems pretty tough to get the system put together - honestly, the wheel speed sensors might be the easiest part of the system...

 

[eaw46]

Here is how we do it in a Hummer and I did try it with my 6X6s and it helps but does not work as well. Eddy


The HUMMER diffs were designed for ease of use by military drivers, and it's my understanding from talking to many military HMMWV drivers that they have NEVER heard of "brake-throttle modulation", the most common comment being, "we just go till we get stuck, then put it in hi-lock and rock it back and forth till we get out".
As I understand it, BTM was discovered kind of by accident, and was not a design feature, but it WORKS.
I have a method I call "Constant-torque Modulation" which I find works even better than the standard BTM in the most extreme situations.
One of the things I found at Moab was that finesse is everything, and large power changes, rushing obstacles, jamming brakes and otherwise being ham-handed is detrimental to forward progress and wallet thickness, so I experimented with a modification of BTM.
When I approach an obstacle, I set up for the climb and when ready I apply FULL brakes. Then, I apply throttle and run the engine up into the best-torque range AND LEAVE IT THERE. In other words, I keep the throttle pressure the same throughout the climb. Then I use the BRAKES to adjust speed, NOT the throttle.
I have found that for the most extreme situations that this provides a much smoother climb with less slippage, bouncing, pounding or traction-breaking. I watched other drivers as they would approach, begin the climb, modulate, and then goose the gas part way up because they felt they were slipping. All this did was screw them up.
The constant-torque method offers you the most available torque for the whole climb at a steady power-state which does not fluctuate, while also ensuring that your Torsen's will be fully locked at all times so you don't spin a wheel and possibly snap a half-shaft through weak modulation pressure. The power input to the wheels is very smooth and I have been able to calmly walk up virtually every obstacle I have ever done at Moab with the sole exception of the Rockpile in Pritchett canyon, which required a slight run for inertial assistance due to my weight.
I most especially use constant-torque on DOWNHILLS, where it provides very, very precise control of your forward progress with little chance of accidentially "goosing" the pedal as you slide off the edge and bang down onto something on Nosedive, something I observed was a real problem. With the brakes already fully on, you just let off a hair to creep forward as needed.
Yes, it's hard on brakes and tranny, and should only be used on the severest of obstacles, using regular BTM on less demanding ones, but it's worth the effort, as it results in a smooth, finessed crawl rather than a banging, clanking gut-buster.
Try it sometime, you'll like it.


Posted from the Hummer Knowledge base. Humvee.net

 

[mudguppy]

Torsen diffs are not open diffs - they rely on torque bias, which is why applying more brake allows the 'seeming' transfer of power. It actually just changes the bias of the diff - the brakes don't transfer the power, the diff bias does.

 

[Mercunimog404]

Here is how we do it in a Hummer and I did try it with my 6X6s and it helps but does not work as well. Eddy


The HUMMER diffs were designed for ease of use by military drivers, and it's my understanding from talking to many military HMMWV drivers that they have NEVER heard of "brake-throttle modulation", the most common comment being, "we just go till we get stuck, then put it in hi-lock and rock it back and forth till we get out".
As I understand it, BTM was discovered kind of by accident, and was not a design feature, but it WORKS.
I have a method I call "Constant-torque Modulation" which I find works even better than the standard BTM in the most extreme situations.
One of the things I found at Moab was that finesse is everything, and large power changes, rushing obstacles, jamming brakes and otherwise being ham-handed is detrimental to forward progress and wallet thickness, so I experimented with a modification of BTM.
When I approach an obstacle, I set up for the climb and when ready I apply FULL brakes. Then, I apply throttle and run the engine up into the best-torque range AND LEAVE IT THERE. In other words, I keep the throttle pressure the same throughout the climb. Then I use the BRAKES to adjust speed, NOT the throttle.
I have found that for the most extreme situations that this provides a much smoother climb with less slippage, bouncing, pounding or traction-breaking. I watched other drivers as they would approach, begin the climb, modulate, and then goose the gas part way up because they felt they were slipping. All this did was screw them up.
The constant-torque method offers you the most available torque for the whole climb at a steady power-state which does not fluctuate, while also ensuring that your Torsen's will be fully locked at all times so you don't spin a wheel and possibly snap a half-shaft through weak modulation pressure. The power input to the wheels is very smooth and I have been able to calmly walk up virtually every obstacle I have ever done at Moab with the sole exception of the Rockpile in Pritchett canyon, which required a slight run for inertial assistance due to my weight.
I most especially use constant-torque on DOWNHILLS, where it provides very, very precise control of your forward progress with little chance of accidentially "goosing" the pedal as you slide off the edge and bang down onto something on Nosedive, something I observed was a real problem. With the brakes already fully on, you just let off a hair to creep forward as needed.
Yes, it's hard on brakes and tranny, and should only be used on the severest of obstacles, using regular BTM on less demanding ones, but it's worth the effort, as it results in a smooth, finessed crawl rather than a banging, clanking gut-buster.
Try it sometime, you'll like it.


Posted from the Hummer Knowledge base. Humvee.net[

Oops

 

[Lieutenant Dan]

Mud and water doesn't bother standard ABS rings/sensor pairs, so this one wouldn't be any more vulnerable.

Wrong, mud is the worst on abs sensors. I had a 08 wrangler 6" lift with 37's. It had abs and ebs systems where the brakes could take over of to much body roll was sensed through a gyro I believe. When you put it in 4x4 Low the computer automatically turned off the abs. Get some good mud packed in there and try doing a steep downhill decent. Abs is not fun off road. Plus I think your trying to over complicate a simple vehicle. KISS is what comes to mind.

Now I'm not trying to bash you or tell you what to do, but in a offroad vehicle such as a deuce lockers will far better serve from traction control.

 

[Heath_h49008]

Oh this is a thought experiment at this point.

I'm just trying to probe the hive mind here to see what others might think. I know it's possible, but wonder if it can be made practical with some creative parts swapping.

Cutting corners by say... grabbing a 4 wheel ABS/traction control module out of the junk yard and rigging it up for the whole trunnion in a 6x6, or all 4 wheels in a bobber. That would need to be matched for fluid capacity, 12v power and the wheel sensors. Possible? I don't know. An F450 would seem to be a near direct swap for a bobber. But the only way to know is to talk it out with the only bunch of guys I know of who have any idea of what I'm talking about.

Sticking a reluctor ring on a hub inside a drum would seem to me to be the best way to keep it clean and functional. I've seen them fail when cracked, as in the old F-150s that used to get a cracked reluctor rings and activate the ABS on every rotation, but I've never seen one packed with dirt/mud just stop reading at all. Did it kick a code?

 

[Lieutenant Dan]

Yeah something about fault reading I such a such wheel speed sensor. It got bad a few times, it wouknt read one sensor and the computer would think that wheel wasn't spinning so the computer thought it was locked and skidding so it would cut engine power and brake opposite corners aka traction control. It was a know problem in the new jk wranglers so some guys found the wiring and tapped a switch into it disabling the abs/ebs systems.

 

[ATPTac]

I've actually seen just overall road debris and rust build up on an ABS rings cause a failure (I've seen this problem on several 04-08 Maxima's). On the ones I've dealt with the ABS ring was part of the hub/bearing assembly, if it goes long enough it actually damages the ABS ring and the wheel speed sensor. The instances I've seen cause the ABS to very sporadically activate when driving at low speeds. Unfortunately every case I've had, the hub/bearing had to be replaced and the wheel speed sensor as well.

I guess the whole point of me writing that was to say that any kind of build up on an ABS ring can damage the system and cause it to go haywire.

Now I think that Heath has a very interesting idea. I'd love to see it done and see the engineering that goes into it. Would I want to put this system on my truck? Probably not, one of the reasons I got an M35 was for the simplicity of the truck, plus I'd rather spend the money that would go into this system on lockers and/or other upgrades. But I definitely think it would be something very cool to have on one of these trucks, and would absolutely justify bragging rights.

 

[Flyingvan911]

My 2008 E-150 has a big gear behind the hubs that the ABS sensor reads. I think lockers might be the better way to go. Even an experienced person could get hammered if the modified brake system fails and hurts someone. No trying to shoot down your idea but I thought the liability issue might be a good thing to keep in mind.

 

[mudguppy]

... That would need to be matched for fluid capacity, ...

The thing that's different between ABS and traction control is the action that is taken when speed differential (slip in TCS, stall in ABS) is sensed:

• ABS - opens a valve to momentarily relieve braking pressure in the stalled wheel zone in order to let the stalled wheel(s) regain speed, then close to let the braking system re-apply pressure, and repeat (rapidly) until speed differential is within tolerance. This is typically the speed differential value between either front wheel compared to either rear wheel, then pressure it typically relieved to the entire zone of the braking circuit - F/R or FR/FL/R.
• TCS - senses wheel speed differential and utilizes a separate hydraulic system to independently apply braking pressure to the specific slipping wheel(s) until speed differential is minimized.

This is way more complicated than salvaging junkyard parts and putting 12V to it. OR, start looking for a luxo SUV TCS module/system and start dissection / analysis.

 

[jesusgatos]

Cheapest/easiest way to use the brakes to improve traction is to add cutting brakes. Nothing automatic about it, but it's effective (compared to open diffs).

 

[ducer]

For ABS you could source the parts from Bosch for their over the road trucks but be prepared to spend upwards of $10,000. You havent even touched on the shieled wire for the sensors (emi).
Cutting brakes or lockers easy and effective and comparably cheap!

Denny