Let's Make Robots!


pull things with intelligent traction control

What will it do?

- Try to pull a heavy object for a given time or distance

- RC with driving aid (Hybrid)

- Maby long range with a trailer (extra battery's)

- Maby some other ideas I get from you...

About the first video: This is the first autonomous pull it ever did! It did pretty well, not as good as manual RC but above expectations. I tried to simulate a pull in the code. Start with a little bit of power to tention everything, Build up the power till it starts to roll, floor it and go!

The video also demonstrates whats wrong; the nose jumps a lot. Looks cool but doesnt go anywhere. Thats why you need traction control and some tilt sensing technique. Traction above raw power. 

And how will it do that?

- With encoders at the back wheels

- An arduino

- A 20A RC speed controller 

- Ordinary traction control 

- Some things i havent figured out yet such as, line following sensors, an internal amp meter to measure power, distance measuring sensors and tilt sensors

- With help, A self learning traction system. 

- Maybe some other techniques I get from you...


What works right now:

Servo steering

BEC Power from the speed controller for the arduino and servo. Only 1 battery needed and no extra circuitry!

Potentiometer Driving(running behind it turning knobs...)


What problems occured:

- the battery is flat after just one pull like in the video! Maybe because the battery is old, maybe because of the amps drawn when it is almost stalling...


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"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..
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.

You know what would improve traction but add very little complexity or weight? A wheelie bar.

You could spring-load it and use a mechanical limiter to keep all 4 wheels on the ground, or failing that at least keep the back 2 on the ground with good force.

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
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.
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.

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 ;-) 

Heh heh, then you should probably disregard everything I said! My solution is probably somewhat atypical!!
the rethink piece you said is highly usable! Simple yet theoretically effective!