.Modelica_Requirements.Examples.AircraftRequirements.LimitedControlFrequency

Information

This example demonstrates the modeling and verification of the following aircraft requirement:

Requirement:
The frequency of the control signal of the valve must not exceed 1.5 Hz during more than 2 seconds.

This is an informal requirement. It is interpreted in the following formal way:

Formalized requirement:
The mean frequency of the control signal of the valve must not exceed 1.5 Hz during any 2 seconds time window. The mean frequency freqHzMean in this window is defined as

T        : Length of sliding window (= 2 seconds)
nCrossing: Number of threshold crossing edges of check in the last T seconds

if nCrossing > 1 then
  freqHzMean = 1/(T/( (nCrossing-1)/2 ));
else
  freqHzMean = 0
end if;

This requirement can be modelled with the ChecksInSlidingWindow.MeanFrequency block.

Setup of this example:

results in

	simulation result