Realtime Optimization in Dymola

Question

I was wondering if anyone who has used the Optimization Library in Dymola has been able to utilize the RealtimeOptimization function without having explicit plant constitutive equations to input into the criteriaFunction? Specifically, I am trying to use some of my model's states as the criteria function, but when I input y[1] := mymodel.state; with or without quotes around the state, Dymola rejects the function. Any thoughts would be very helpful. Thank you.

Answer 1

You could try adding outputs (Modelica.Blocks.Interfaces.RealOutputs) to the top level of the model and then linking these to the states by using Modelica.Blocks.Sources.RealExpression blocks.

Then when using the optimisation function goto the criteria page and use the Select button and select these outputs to add them as criteria.

Answer 2

It is not possible to have access to model variables inside a function. You have to provide the values of the variables through the inputs to the function. The task RealtimeOptimization is aimed to be called during the simulation of a Modelica model. The criteria function has the defined inputs nTuners, nCriteria, tuners[nTuners]. You can add additional input variables, see the Example Optimization.Tasks.RealtimeOptimization.Examples.Example02.RunSampled and the record UserData in the function Optimization.Tasks.RealtimeOptimization.Examples.Example02.criteriaFunc02. By these additional variables you could transfer some state variables into the critiera function.

Maybe we can assist you, if you provide more information about your setting. I am the main developer of the Optimization library in Dymola.