k4nnon Posted October 18, 2023 Report Share Posted October 18, 2023 Hey all Link G4x PnP user here. I have a question in regards to setting up traction control/power management in my vehicle. I have a 2006 USDM evo 9 that I am getting ready to send individual wheel speed via CAN to the link. However the evos use a trans speed sensor for vehicle speed. How is the link going to know when there is a loss of traction to implement the traction control/power management being that all 4 wheels are drive wheels? A loss of traction would only indicate an increase in mph/rpm correct? Im confusing myself. Please let me know if anyone has any input on this thankyou!! Quote Link to comment Share on other sites More sharing options...
koracing Posted October 18, 2023 Report Share Posted October 18, 2023 If you are sending all 4 wheel speeds to the ecu, then seeing a difference exceeding somethreshold in those wheels speeds should indicate a lack of traction. I'm assuming you don't have all 4 wheels fully locked together when driving - there should be some type of differential coupling that allows enough slip and potentially cause a large difference of speed between 1 or 2 of the wheels compared to the rest. Alternatively you can try to fit a GPS based speed sensor that would be your "actual speed" versus vehicle reported speed, but I don't know how well or fast a GPS sensor acts. Perhaps something can be done using the internal accelerometer versus rate of change of vehicle speed? k4nnon 1 Quote Link to comment Share on other sites More sharing options...
k4nnon Posted October 18, 2023 Author Report Share Posted October 18, 2023 @koracing hey thanks for the reply. I assume that a loss of traction would probably exceed some particular mph within a certain amount of time and kick the traction control to start working but I would have to actually figure out what that limit is, which may be difficult, especially on different surfaces. I seen in the "share your math block" forum someone posted a math block to calculate front wheel vs rear wheel slip for awd. Maybe I can set up something like that and use a math block to determine slip amount? Thanks again for the input! Quote Link to comment Share on other sites More sharing options...
koracing Posted October 18, 2023 Report Share Posted October 18, 2023 I think with what's actually there in the ecu already that makes the most sense to me would be wheel speed versus accelerometer. Not sure exactly how you would go about setting it up though. Quote Link to comment Share on other sites More sharing options...
k4nnon Posted October 18, 2023 Author Report Share Posted October 18, 2023 I had some conversation with a coworker and I can just reassign my vehicle speed source to one of my wheel speed inputs instead of transmission speed sensor. That tales care of the wheel speed/trans speed issue. Just need to find a proper way to determine wheel slip while all 4 wheels are driving wheels. Like you mentioned, Im sure there will be a visible difference in a log when traction loss is happening. Its gonna be a bit before im able to test some things but forward thinking the process.. Thanks again for the added input. If you have anymore suggestions/ideas let me know! Quote Link to comment Share on other sites More sharing options...
Confused Posted October 18, 2023 Report Share Posted October 18, 2023 The Slip calculation for Traction Control needs to see a difference between Driving (powered) and Driven (unpowered) speed sources, to determine when to cut power... From the Help, your options for speed sources are: LF Wheel Speed RF Wheel Speed LR Wheel Speed RR Wheel Speed Average Front Speed Average Rear Speed Min Front Speed Max Front Speed Min Rear Speed Max Rear Speed Average Four Wheels GP Speed 1 GP Speed 2 GP Speed 3 GP Speed 4 Outside Front Speed Outside Rear Speed GPS Speed With 4 Driving (powered) wheels, though, the faster wheel could be either front OR rear, left OR right, so none of those are really suitable for finding an "obvious" way of determining slip - unless you can find a GPS Speed sensor which reacts quickly enough - a fast-acting 100-200Hz one is pretty expensive though! Your gearbox speed sensor is essentially "Average Four Wheels" - so not sure that this will gain you much... but maybe there's something I've missed! I've also got a 4WD Mitsubishi - a Legnum VR-4, this has some form of Traction Control - so someone out there somewhere has figured out a way of doing it with just 4 wheel speed sensors, gearbox speed sensor and maybe the accelerometers from the AYC/ASC system... k4nnon 1 Quote Link to comment Share on other sites More sharing options...
k4nnon Posted October 19, 2023 Author Report Share Posted October 19, 2023 @Confused hey thanks for the input. Im actually not even sure this traction control adventure is a possibility or not. It doesnt sound like there is a good way to separate driving wheels from slipping wheels in an awd system like mine. There is essentially no undriven element. Ill keep thinking but may be a lost cause haha. Thanks for the input and if you think of anything else please let me know. Quote Link to comment Share on other sites More sharing options...
koracing Posted October 19, 2023 Report Share Posted October 19, 2023 There must be a way to use the built in accelerometer in the Link with possibly a math channel to turn into driven wheel speed... Quote Link to comment Share on other sites More sharing options...
Adamw Posted October 19, 2023 Report Share Posted October 19, 2023 Yeah, there are not too many easy options with AWD systems like the Evo. For straight-line type racing or launching it is more common to do some sort of open loop power management based on some predetermined curve of maximum possible wheel speed acceleration vs time or speed. I have seen LIDAR or RADAR and even fifth wheels used in some applications. The G5 would likely be able to do closer to traditional slip based TC using its "GPS". The G5 uses a high speed GPS with sensor fusion and dead-reckoning which should remove most of the typical lag from GPS reported speed (not fully implemented or tested yet). Confused 1 Quote Link to comment Share on other sites More sharing options...
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