Have you ever looked at a
Have you ever looked at a tractor? All the weight is in the front. You have to keep the center of gravity as far forward as possible. I don’t understand why you think “traction control” is going to help you pull more weight. You aren’t losing traction, which is the only circumstance where traction control is useful. It’s not like the arduino is going to make your motors stronger.
That is true but it would
That is true but it would also take the traction off the back wheels. Have a look at this: http://www.youtube.com/watch?v=xn66IzXP5Ag my bot will probably behave the same on loose stuff
A bit more on the slow type of tractorpulling…
There are two types of tractorpulling. The fast and spectacular one, and the slow and technical one. My aim is more at the slow type. Thats because i want to learn more about traction control systems. There will be no lifting in the slow type of tractorpulling. Thats why i need the traction control systems. I want my bot to be unbeatable when there is almost no grip at all!
Just to get a few things clear 
Crossed wires
Ah, yes. You can do slip-diff traction control by adding rotary position sensors on the powered wheels. I don’t know how effective that would be on a small model, though, if both wheels are spinning (as seems likely).
Having thought about my last post a little more, I also think you might be able to do something novel to allow you to use only rear wheel encoders for the case where both rear wheels are spinning. Here’s my thinking: for any given current through your motors, there may well be an expected maximum speed. If the wheels are turning too fast for the amount of current being supplied, then they must be spinning. For example, if you’re putting 10A (ha ha) through your motors and the wheels are spinning at 60RPM, then they’re probably not slipping. If they’re spinning at 600RPM, then they probably are.
Edit: Actually, that’s complete rubbish. Tamiya models can draw 10A when they’re going like stick and also when they’re under load.
Rethink: What you need to do is look for a rapid, uncommanded speed increase. Clearly, if your’ making a high-torque tractor, you’ll want to ramp the current slowly. If the wheels start moving disproportionately quickly, you need to back off on the juice.
Pullin’
Heh heh, then you should probably disregard everything I said! My solution is probably somewhat atypical!!
"What you need to do is look
"What you need to do is look for a rapid, uncommanded speed increase." WOW! thats a very interesting thought! I will try to realize it when I have got the encoders on. What I also want to test: Encoders on all the wheels, the fastest wheel can spin only 5% or so faster than the slowest measured speed in a straight line. The wheel size corrected off course…
the rethink piece you said
the rethink piece you said is highly usable! Simple yet theoretically effective!
It depends on where the load
It depends on where the load is connected, if the connection point is forward from the rear wheels it’ll stop the front coming up. If the load connection is behind the rear wheels then because the wheelie bar is unpowered it will still help resist any rotation about the connection point.
True
Following our regulations based on the original, the load is connected behind the axle and level or lower than the axle. Maybe i will put one on. There is a wonderful connection point i could use.
Yes
Yours is the obvious way to do it and I think that’s probably what’s used in cars in combination with slip diff. You still have the problem of the front wheels lifting, though. On the other hand, if you wanted to make a speed machine, you could get teh best acceleration by cmparing the speeds of teh powerd and unpowered wheels. If the powered wheels are moving more rapidly than the unpowered then you back off the juice. That would give maximum traction during a straight-line start. Still have the problem of the front wheels lifting, on a real speed machine, though.
