FridgeFreezer Posted April 18, 2008 Author Share Posted April 18, 2008 There are TC routines in development for MS (besides the existing rate-of-rise anti-rev one) although you could bodge it by connecting wheel speed sensors to a comparator and when a threshold is reached it triggers the knock sensor input on the MS, that would then do the retarding thing. I guess the GPS setup would need to compare wheel speed to GPS speed to decide if you were spinning? Quote Link to comment Share on other sites More sharing options...
Astro_Al Posted April 18, 2008 Share Posted April 18, 2008 Would GPS have the resolution to do this? Al. Quote Link to comment Share on other sites More sharing options...
dollythelw Posted April 18, 2008 Share Posted April 18, 2008 it gets speed down pretty well Al Quote Link to comment Share on other sites More sharing options...
LandyManLuke Posted April 18, 2008 Share Posted April 18, 2008 Most GPS receivers have an update frame time of 1s - that'd be pretty poor. the ETC i'm designing has a frame time of 4ms. GPS is good for speed because it measures displacement over time, using a moving average i would imagine. Unless of course you can get hold of GPS receivers with a quicker frame time? maybe DGPS/survey units can do it? Quote Link to comment Share on other sites More sharing options...
Astro_Al Posted April 18, 2008 Share Posted April 18, 2008 But even then, your speed is a derivative of your position (change of) - so is fundamentally limited by the resolution of the position no matter how fast you can sample. Thats whats confusing me. But hey - if it works, it works! Al. Quote Link to comment Share on other sites More sharing options...
Daan Posted April 18, 2008 Share Posted April 18, 2008 Its been used in WRC for quite some time actually. The ecu compares wheelspeed with gps speed (in forward direction) and cuts engine power by retarding the ignition if it thinks there is too much power. If the GPS signal is not clear than a groundspeedsensor is used as the second option. this is basically a radar that looks forward down to the road at an angle. The radar sensor is now banned, but I think the GPS sensor could still be utilised for this. Pi research did all the work for mainly Ford and Skoda. Daan Quote Link to comment Share on other sites More sharing options...
david1701 Posted April 19, 2008 Share Posted April 19, 2008 wow, i woulda thought that the gps lag would have been an issue aswell, cos the problem is latency in the circuit (ie how instantaneous corrections are) and that this can be a problem just building normal traction control computers, let alone adding in a huge 2 way lag of talking to a satellite. Quote Link to comment Share on other sites More sharing options...
LandyManLuke Posted April 19, 2008 Share Posted April 19, 2008 1 way. GPS receivers don't talk to satellites. I don't know any details of the system Daan's talking about, but i think it's fair to say it'll be well removed from civilian/hobby GPS receivers. Quote Link to comment Share on other sites More sharing options...
david1701 Posted April 20, 2008 Share Posted April 20, 2008 well then, i apologise for my ignorance, i shall go and edumacate myself on gps Quote Link to comment Share on other sites More sharing options...
steve_d Posted April 20, 2008 Share Posted April 20, 2008 I know nothing about electronics but for the traction control with GPS I would have thought the system would just assume the speed had remained constant from the last GPS calculation which others have said may be a relatively large gap. During this time a faster calculation could be taking place using the wheel speed sensors and appropriate power reductions taking place. Steve Quote Link to comment Share on other sites More sharing options...
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