Position and velocity integral in Simulink

Hello, my problem is as follows:

When I use two integrals to compute velocity and position from an acceleration, and I have limits on the position integral, I need the velocity integral to not 'windup' when the position is limited. That is, the velocity should be reset to 0 as long as the position is limited. However, if I do this using the saturation port of the position integral and a hold level reset on the vel. integral, the position will stick to the limit as the velocity is unable to change from 0 again.

How do I accomplish this?

Thank you

Rasmus Larsen

Answer 1

[Guy Rouleau]

The Second Order Integrator is designed especially for that:

http://www.mathworks.com/help/simulink/slref/secondorderintegrator.html

Answer 2

[Rasmus]

I seem to have been able to do it using the saturation port and an 'either' reset port. However the simulation grinds to an absolute halt with this setup. Any advice?

Edit: No, it still does not work. It's really not possible to use the saturation port in any simple way to fix this..