Optimization and Automated Tradeoff

Import Models to Optimize

To open the CAGE browser and set up your optimization:

1. Start the CAGE Browser part of the Model-Based Calibration Toolbox™ product by typing

   cage
   

2. If you have not imported models, click Import Models. After you have imported models, you can optimize them.

   For any optimization, you need one or more models. You can run an optimization at a single point, or you can supply a set of points to optimize. The steps required are:

   1. Import a model or models.

   2. Set up a new optimization.

3. If you have imported models, click Optimization in the Processes pane.

   

You can use the Optimization view to set up, run, view, and export optimizations. You must also set up optimizations here in order to use them for automated tradeoff.

When you first open the Optimization view both panes are blank until you create an optimization. After you set up your optimizations, the left Optimization pane shows a tree hierarchy of your optimizations, and the right hand panes display details of the optimization selected in the tree, as with other CAGE processes.

The following tutorial guides you through this process to evaluate this optimization problem: MaxTQ (SPK, N, L).

That is, find the maximum of the torque model (TQ) as a function of spark (SPK), engine speed (N), and load (L). You will use the NOXFLOW model to constrain these optimization problems.

For any optimization, you need to load one or more models. You can use the CAGE Import tool to import models from Model Browser projects. For this tutorial you can load a CAGE project from the mbctraining directory that contains two models for the optimization problems. Load the project containing models to optimize as follows:

1. Select File > Open Project to choose the tradeoffInit.cag file, found in the matlab\toolbox\mbc\mbctraining directory, then click OK.

   The tradeoffInit.cag project contains two models and all the variables necessary for this tutorial.

2. CAGE displays the Models view. You can view your models at any time by clicking the Models button in the Data Objects pane.

   

   Observe that the project you have opened contains two models: TQ_Model and NOXFLOW_Model. In this tutorial you use these models to optimize torque values subject to emissions constraints.

3. To view the items in the Variable Dictionary, click the Variable Dictionary button in the Data Objects pane.

   

   The Variable Dictionary view appears, displaying the variables, constants, and formulas in the current project. The project already has the relevant variables defined, so you do not need to import a variable dictionary. Note that the variables have ranges and set points defined.