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From: Georges Alban on 15 Mar 2010 07:47
I've developed a simulink-model for the revolution control of a PMSM (from Simpower library). But the auto-tune functionality of the PID is generating some errors ("To many outputs requested. Most likely cause is missing [] around left hand side that has a comma separated list expansion"). I've already watch the webinar on this topic, but no solution. Can somebody help me to resolve this? Thank you in advance for your support.
From: Rong on 15 Mar 2010 14:41
I'm contacting Georges for more information. Stay tuned.

Rong
From: Rong on 15 Mar 2010 17:06
Hi, Georges,

The error dialog you saw was a known bug and fixed in our R2010a release. Meanwhile, please refer to the following bug report and implement the workaround for R2009b.

http://www.mathworks.com/support/bugreports/583793

One more thing. You will see a new error dialog shown below after the previous one is gone, stating that "Linearization aborted because the linear plant model seen by the PID block is effectively 0."

It is a legitimate error message because the linear plant at the initial operating point (in this case at t=0) is a static gain of 0, which cannot be used to tune PID.

To fix it, use Control and Estimation Tools Manager to analyze your model and determine why the plant linearizes to zero.

To perform this analysis, use the Simulink Control Design linearization tools to create the same linear model seen by the PID controller. To define the plant for linearization:

• Create a linearization input point at the controller output: Right-click on the signal at the PID Controller block output, and select Linearization Points > Input Point from the drop-down menu.

• Create a linearization output point at the controller input: Right-click on the signal at the PID Controller block input, and select Linearization Points > Output Point from the drop-down menu.

• Create an open-loop point at the controller input: Right-click on the signal at the PID Controller block input, and select Linearization Points > Open Loop from the drop-down menu.

For more information about linearization points, see user guide on “Selecting Inputs and Outputs for the Linearized Model”.

After you create the linearization points, use the procedure described in “Steps for Linearizing Models Using the GUI” to linearize the plant in your Simulink model. You can then analyze your model to determine why it linearizes to zero and take corrective actions. See “Troubleshooting Exact Linearization Results” for information about correcting linearization problems.

Hope it helps.

Rong
From: Rong on 15 Mar 2010 17:14
Hi, Georges,

The error dialog you saw was a known bug and fixed in our R2010a release. Meanwhile, please refer to the following bug report and implement the workaround for R2009b.

http://www.mathworks.com/support/bugreports/583793

One more thing. You will see a new error dialog shown below after the previous one is gone, stating that "Linearization aborted because the linear plant model seen by the PID block is effectively 0."

It is a legitimate error message because the linear plant at the initial operating point (in this case at t=0) is a static gain of 0, which cannot be used to tune PID.

To fix it, use Control and Estimation Tools Manager to analyze your model and determine why the plant linearizes to zero.

To perform this analysis, use the Simulink Control Design linearization tools to create the same linear model seen by the PID controller. To define the plant for linearization:

• Create a linearization input point at the controller output: Right-click on the signal at the PID Controller block output, and select Linearization Points > Input Point from the drop-down menu.

• Create a linearization output point at the controller input: Right-click on the signal at the PID Controller block input, and select Linearization Points > Output Point from the drop-down menu.

• Create an open-loop point at the controller input: Right-click on the signal at the PID Controller block input, and select Linearization Points > Open Loop from the drop-down menu.

For more information about linearization points, see user guide on “Selecting Inputs and Outputs for the Linearized Model”.

After you create the linearization points, use the procedure described in “Steps for Linearizing Models Using the GUI” to linearize the plant in your Simulink model. You can then analyze your model to determine why it linearizes to zero and take corrective actions. See “Troubleshooting Exact Linearization Results” for information about correcting linearization problems.

Hope it helps.

Rong
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