How works the ConfigurableJoint?

Hi

I'm using the configurable joint in order to simulate some pistons (slider) constraint. As first example I'm trying to model a simple lift with and without load (think to a forklift).

The physic rig is pretty trivial (anchor and limit parameters) and works as expected moving the component in the editor, but the control of this constraint is very very strange.

I'm using the 2018.1.0f2. The slider/constraint act on Y, so I've configured the Y drive using a maximumForce and TargetVelocity adding a speed on Y. I've tried tiny and huge values for both parameters but I cant see no movement.

So, I've tried to add some value != 0 inside the PositionDamper field and the constraint start to move.
Ok, but is uncontrollable like that!! First of of all I'm not able to understand why I need to use PositionDamper parameter in order to see a movement. Then, if there is a load on constraint (on the forks) the PositionDamper need to be bigger in order to see the movement. Unfortunately, if there is no load the contraint velocity is much bigger, se we need two different configurations with load or without.

This behaviour doesn't make sense: the motor behaviour (up/down movement) have to be the same with or without load (assuming to setup a correct force value for the mass to lift-up).

I'm thinking to the hinge constraint: I need velocity and force parameters only in order to do a correct movement. I think the PositionDamper just confusing me.

Can you suggest to me some correct configuration?

Many thanks, bye

 

No idea?