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Tutorial #5: Optimization

To find the input settings that would make the Red Ball go 70 inches and the Green Ball go 60 inches, we need a more powerful tool than the surface plot. DOE PRO comes with a powerful feature called "Multiple Response Optimizer" which allows us to find inputs that meet our output goals.

 

First, we need to select the regression table that has the model we would like to optimize. Click on the worksheet entitled "Regression Table (2)" by using the "tabs" at the bottom of the worksheets. The active worksheet should be our second regression model. To start the optimizer, select "DOE PRO" - "Graphs and Optimization" - "Multiple Response Optimizer…" from the Excel menu bar. The Optimizer will now start the process of finding out how and what we want to optimize.

 

First we will tell the optimizer a little about our inputs. Specifically, we will define the range in which we will allow the optimizer to search for an ideal solution. We will also tell the optimizer if our inputs are continuous or not. Remove the check mark next to "Stop Angle" to tell the optimizer that the input is discrete (we can’t have a stop angle of 2.5, only 2, 3, or 4). Click "OK" when done.

 

Optimizer step 1

 

Next, DOE PRO will give us the option to enable "Cpk Optimization". We are not going to use Cpk Optimization in this example, so click on "OK" to move to the next step.

 

Optimizer Step 2

 

The next window that appears is the "Multiple Response Optimizer (Step 3 of 3) - Constraint Editor". It is here that we will tell DOE PRO that we want the Red ball to go 70 inches and the Green ball to go 60 inches. When we first come to this screen the "Current Constraints" box is empty.

 

Optimizer Step 3

 

Change the "Type Optimization" to "=" and type in the value "70" under "Target Value" and press the "Add Constraint" button.

 

Optimizer step 4

 

Change the "Response" to "Green Ball" and change the "Target Value" to "60". Press the "Add Constraint" Button.

 

Optimizer step 5

 

The "Current Constraints" area should now indicate that we have two constraints.

  • "Red Ball: Set Y-hat=70 - Weight=50"
  • "Green Ball: Set Y-hat=60 - Weight-50"

We are now ready to press the "Optimize" button. DOE PRO will attempt to find a combination of the inputs that will meet our output constraints. When DOE PRO is done, the input values will be displayed at the bottom of the screen. If you don’t like the settings DOE PRO has found, you can press the "Optimize Again" button.

 

Optimizer Step 6

 

When you are happy with the results of the Optimizer, click on the "Settings To Worksheet" button. The Optimizer will place the optimal input settings into the "Prediction" area of the regression worksheet.

 

Optimizer Result

 

For more information on other features in DOE PRO, see the user's manual or help system.