How do I write an If into a IPG variable instead of a switch in CM4SL?

alberto · 30 January 2022 13:20

I am currently developing an IPG model in Simulink to simulate the Driver Aids of a Formula Student car.
The problem I am facing is that I want to write a 0 into a variable (PT.Control.Engine.Trq_trq) given certain condition, but when that condition does not fulfill I want the variable to remain as IPG calculates it.
By using an If block, IPG gives me an error about subsystems conflict. Also I tried by writing the same variable (PT.Control.Engine.Trq_trq) in a switch into the same variable, but it did not work.
Right now I am using the structure in the figure. Does anyone know how to implement this?
Thank you,
Alberto

mariano.carpinelli · 31 January 2022 16:04

Hi Alberto, thanks for your question.

You should be able to use both the switch approach (see below):

mariano.carpinelli · 31 January 2022 16:05

and the “if” block approach:

mariano.carpinelli · 31 January 2022 16:05

I have tested the 2 configurations in the screenshots above and they are equivalent (the Engine Torque Target calculated internally by CM is used for the first 10s and after that a 0 target torque is assigned).

The details of the implementation, i.e. which CM signals you need to read/write, depend on the powertrain configuration you are using. In the example above I used the Examples/DemoCar with a convetional powertrain. However to be able to use the PT.Control.GasInterpret.Trq_trg and PT.Control.Engine.Trq_trg signals, the Gas Interpreter option needs to be selected in the PT Control tab:

I hope this helps.

Cheers,
Mariano