[ODE] How to calculate force ?

[Marco Vienup]

Hello everyone,
i am working on a six leged robot simulation using ode for the physics.
Now I want calculate the force which each leg is pressed to the ground. 
Draft:
		**  Leg
            **
            **
         ======== Ground
            ^^
            ||   Searched force   


My first effort was to use a contact joint between leg and ground.
and then use dJointGetFeedback to get the force.
After each worldstep I delete all contacts so I got wrong 
( not calculated ) values from the dJointGetFeedback function.
So I tryed to to create the contact joint only once and call
worldstep a couple of times so it can calculate good values.
But now my problem is that my robot bounces on the ground and
then he is flying away :o). I would think that I use wrong
parameter for dContact...
Perhaps someone can tell me an even more easier way to get my force.
Or an example how to set um the contact joint.

Thx a lot

Marco