Traction control for an M35 series.

[Recovry4x4]

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).

This is exactly my thoughts and if you need automatic, the NoSpin has been rock solid for 60 years.

 

[Heath_h49008]

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.

That's about what I'm thinking. Most of the SUVs built in the last few years have pressure generating ABS/Traction control systems because it's linked with the mandated stability systems.

Obviously a plain ABS module wouldn't do it.

But thinking about pressure and fluid capacity, our wheel cylinders are much smaller than disk systems, so that might not actually be that tough to find.

Dealing with the stability control might be ugly, or it might not. I don't know enough about the systems inter-connectivity to know if it could be separated easily in any available module. ABS and Traction Control are really dumb systems. All they do is sense brake activation, and compare hub sensor speed readings.

If: Wheelspeed A > wheel B
and: brakes not applied
Then: Add pressure to wheel cylinder A
Else: Wheelspeed A = 0
And; Brakes applied
Then: Release pressure from Wheel cylinder A

Repeat that 4-6 times and add a bunch of other "Ifs" and "Else" for speed, and fault detection and you have a system.

It really isn't vastly more complicated a logic circuit. But modulating the required signals could be interesting, and finding a better way to acquire wheel speed looks like a fun problem.

Of course just dropping in lockers is a better idea. I never said this was a SANE thing to do, just a question of how tough would it be to be crazy?

It's winter, and between work and classes I'm becoming a very dull man without some problem to fiddle with.

 

[rustystud]

From my experience working on these systems on large vehicles, they are far more trouble then they are worth. The number 1 issue with brakes is usually the ABS , TCC system . Also you will have to go to DOT 3 fluid since Silicone foams when pulsed . The only reason OEM went to ABS and TCC is because drivers are getting stupid ! They do not know how to drive anymore. Our busses all have these systems and they are more complicated then you think. There interconnected to the engine and transmission ECM's and yes they all use shielded cable (expensive ! ) . You will need a laptop to talk to the system, and the adapters to connect to the module, more money ! Can it be done, sure . Is it wise to do it ? NO. Lockers are a time proven system. Go with what works.

 

[Heath_h49008]

I think some of you are missing the point here...

I'm not asking which is better, lockers or a completely untried system. (That is obvious) This is a thought experiment about what could be done to build an ABS/TC with mostly off the shelf parts.

Yes, lockers are awesome. I will name a child "locker" because they are wonderful in the near future.

 

[bugwhacker]

ABS for a hydraulic brake system is easy enough to do. ATC is a whole other ball game because there isn't an off the shelf ABS/ATC hydraulic controller sized for a medium duty truck that I am aware of. Secondly you would need in addition to the ABS hardware a steering angle input sensor and a way to reduce horsepower to the over all drive-train. A throttle stop might work much like the FDC that is on the Multi. just something to defuel the motor.

All that being said convert over to air brakes and all the parts are there on the shelf waiting for you to build it.

My 2 cents install ABS and lockers. I am working on ABS for the deuce right now and think I have a tone ring worked out for the Big rotor disc conversion.

 

[mudguppy]

he's not trying to reduce engine power to the wheels to prevent slipping (i.e. on a wet road), but rather transfer power from a slipping wheel to a wheel with traction.

...

Heath,

I was actually thinking about this yesterday (now you've got ME pondering it!!!). you would really need the system to look at each axle as a zone and simply compare speeds between each side of each axle: A-B for axles 1 - 3.

Like you said, logic is something straight forward:
If A > B by xx%,
Then apply brake to A,
Until A is near equal to B by xx%

then repeat for the other 2 axles.

I do think it is completely doable in conceptual terms to make a functional system, even if it is a manual on/off switch of when you want to system on - avoiding the complex interlocks of speed, mode, xcase range, etc.

I really think the long pole in the tent is the logistics of a firmware controller making it work, and tieing in the pressure system to the existing single circuit brake system.

I want to see you do it.