[ODE] Rolling Friction and Climbing

[Abheek Bose]

Hi..

I am developing a wheeled robot which can go over obstacles (say a
simple block). The robot has 4 powered wheels and 1 passive castor
wheel at the back. Now this is the problem:

the 4 wheels can climb the box whose thickness/height is less than the
wheel RADIUS.. but the wheel at the back tends to get stuck. This we
have tested on a similar real robot but it does not happen this way.
It seems that it has something to do with 2 contact points

the friction model i am using is with dContactApprox and a parameter mu of 1.3 

I have read the FAQ which recommends using a damping technique to
simulate the rolling friction and have also hunted rolling friction
topics in the mailing list.... but all of these, i guess, are for
rolling on a plane ground.... and not for when it tries to overcome a
small block!

if some1 can come up with any suggestions... it would be really great!
thanx a lot

PS: my thesis depends on this!! 

cheers!