Deactivate a switch block once the threshold is achieved.

Hi! I have a 3dof mass spring damper system and I want to apply a force (exponential law) on it when the velocity of one of the bodies overpasses a zero value (velocity initially negative). I used a switch block but I want it to be deactivated once the force is applied, so that the force will act for the remaining time, since the said velocity has an oscillatory behaviour and when it becomes negative the switch shuts down the force again (and I don't want this). Do you have any suggestions?

Answer 1

[Jonas]

https://nl.mathworks.com/help/simulink/ug/enabled-subsystems.html

[Vito Murgida]

Hi Jonas, thank you so much for the answer!

Honestly I'm not expert with Simulink, I tried your solution but it doesn't work. I obtain a force constantly zero and also the velocity I use as the control signal is constantly zero (it should be negative at the beginning, since this is the initial conditions I gave to system).

If I don't close the loop it works.

I'm quite sure this is not the correct way of using enabled subsystem. If you have any suggestion I will be grateful to you, otherwise, thank you anyway!