Classical Tuning Module

Use the Classical Tuning module to tune the servo system manually or if EasyTune does not produce optimal gains. You can find this module in the Servo Topic of the Configure workspace in Automation1 Studio. Make sure that you are in Basic Editing mode.

IMPORTANT: For more information about the Classical Tuning module and servo tuning, see the Servo Tuning user guide.

Manual Servo Tuning

Use the Manual Servo Tuning tool to manually adjust the servo gains and feedforward gains based on time-series data that is collected during repeated motion. Manual Servo Tuning can help you optimize one move or a small set of moves.

IMPORTANT: Before you use the Manual Servo Tuning tool, the axis that you select must be stable.

  1. In the Axes category of Automation1 Studio, select the Servo topic. Then make sure that you are in the Basic Editing mode.
  2. In the Classical Tuning module, select the Manual Servo Tuning tab at the top of the application.
  3. At the top of the module, click the drop-down arrow to select the axis that you want to configure.
  4. On the Classical Tuning toolbar, click Configure Signals. In the dialog that comes into view, configure the signals that the application will collect while motion is executing. The signals that you configure for the Motion 1 command will also apply to the Motion 2 command. The types of signals that you can collect and plot include:
  5. Configure the Motion 1 and Motion 2 commands before you send them to the controller. To do this, type the commands that you want to use into the adjacent text boxes. For example, you can use the MoveAbsolute() function.
  6. To execute the commands for Motion 1 and Motion 2, click one of the adjacent Execute Command buttons . The controller sends these motion commands to the stage. The stage executes the motion, collects the data, and plots the signals that you collected.
  7. Execute single or repeated motion on the selected axis. Do one of the options that follow:
    • To execute single motion, click one of the adjacent Execute Command buttons for Motion 1 or Motion 2.
    • To execute repeated motion, click the Collect Repeated Motion button .
  8. Adjust the servo gains and feedforward gains. You can do this by entering their new values in the gains boxes at the bottom of the window.
  9. To apply the servo and feedforward parameter values to the controller, click the Apply button.
  10. Execute the motion again. Then examine the performance of the selected axis.
  11. When the performance of the selected axis is satisfactory, click the Save All button on the bottom-left corner of the application. This makes sure that the updated parameters will have an effect after the next controller reset.
  12. If you want to return the servo loop gain values to their most recent configured state, click the Discard button.

Closed Loop Tuning

The Closed LoopClosed A broad term relating to any system where the output is measured and compared to the input. Output is adjusted to reach the desired condition. Tuning tool commands the selected axis to do a predefined sinusoidal motion profile. The tool automatically measures the motion that occurred and calculates a set of servo gains based on the information that you specified. The function of the Closed LoopClosed A broad term relating to any system where the output is measured and compared to the input. Output is adjusted to reach the desired condition. Tuning algorithm is to translate a set of tuning specifications, based on the open-loop magnitude crossover frequency and the phase margin, into a set of servo gains.

IMPORTANT: Before you use the Closed LoopClosed A broad term relating to any system where the output is measured and compared to the input. Output is adjusted to reach the desired condition. Tuning tool, the axis that you select must be stable.

  1. In the Axes category of Automation1 Studio, select the Servo topic. Then make sure that you are in the Basic Editing mode.
  2. In the Classical Tuning module, select the Closed LoopClosed A broad term relating to any system where the output is measured and compared to the input. Output is adjusted to reach the desired condition. Tuning tab at the top of the application.
  3. At the top of the module, click the drop-down arrow to select the axis that you want to configure.
  4. In the Oscillation Options toolbar, configure the oscillation Amplitude (primary units) and Frequency (Hz).
  5. In the Calculation Options toolbar, enter a target Crossover Frequency (Hz) and Phase Margin (deg).

    6. Tip: For information about applicable target values for a range of mechanical devices, refer to the Selecting a Maximum Target Crossover Frequency section of this guide. A phase margin in the range of 32 degrees to 45 degrees is permitted for most conditions.

  6. Click the Start Closed LoopClosed A broad term relating to any system where the output is measured and compared to the input. Output is adjusted to reach the desired condition. Tuning button .
  7. If the axis cannot complete the motion because the controller generates a Position Error Fault, divide the oscillation amplitude or excitation frequency by 2. Then click the Start Closed LoopClosed A broad term relating to any system where the output is measured and compared to the input. Output is adjusted to reach the desired condition. Tuning button to do Closed LoopClosed A broad term relating to any system where the output is measured and compared to the input. Output is adjusted to reach the desired condition. Tuning again.
  8. If the Closed LoopClosed A broad term relating to any system where the output is measured and compared to the input. Output is adjusted to reach the desired condition. Tuning tool tells you that an invalid inertia was calculated, multiply the oscillation Amplitude (primary units) or Frequency (Hz) by two. Then click the Start Closed LoopClosed A broad term relating to any system where the output is measured and compared to the input. Output is adjusted to reach the desired condition. Tuning button to do Closed LoopClosed A broad term relating to any system where the output is measured and compared to the input. Output is adjusted to reach the desired condition. Tuning again.
  9. If the quality estimate is less than 50%, do not apply these changes. Increase the values of the oscillation Amplitude (primary units) and the Frequency (Hz). Then click the Start Closed LoopClosed A broad term relating to any system where the output is measured and compared to the input. Output is adjusted to reach the desired condition. Tuning button to do Closed LoopClosed A broad term relating to any system where the output is measured and compared to the input. Output is adjusted to reach the desired condition. Tuning again.
  10. To apply the servo parameter values to the controller, click the Apply Changes button.
  11. If the axis is stable when the new servo parameter values are applied and if it is necessary for you to have higher dynamic performance, do one of the options that follow:
  12. If the axis is unstable when the new servo parameter values are applied, do the steps that follow:
    1. Reset the controller to go back to the previous servo parameters that are stable.
    2. Lower the value of the Crossover Frequency (Hz) or Phase Margin (deg).
    3. Click the Start Closed LoopClosed A broad term relating to any system where the output is measured and compared to the input. Output is adjusted to reach the desired condition. Tuning button to do Closed LoopClosed A broad term relating to any system where the output is measured and compared to the input. Output is adjusted to reach the desired condition. Tuning again.
  13. When the performance of the selected axis is satisfactory, click the Save All button on the bottom-left corner of the application. This makes sure that the updated parameters will have an effect after the next controller reset.

Open Loop Tuning

The Open Loop Tuning tool moves the selected axis by injecting open-loop current into the axis when it is not under closed-loop control. This tool automatically measures the motion that occurred and calculates a set of servo gains based on the information that you specified. If you use this tool, it is not necessary for the selected axis to be stable or enabled. The function of the Open Loop Tuning algorithm is to translate a set of tuning specifications, based on the open-loop magnitude crossover frequency and the phase margin, into a set of servo gains.

WARNING: Because this is an open-loop tool, use it only when the axis that you are tuning is free from external forces. For example, if an axis moves in the vertical direction and uses closed-loop control to counteract gravity, then the axis will free-fall if you try to tune it with the Open Loop Tuning tool.

  1. In the Axes category of Automation1 Studio, select the Servo topic. Then make sure that you are in the Basic Editing mode.
  2. In the Classical Tuning module, select the Open Loop Tuning tab at the top of the application.
  3. At the top of the module, click the drop-down arrow to select the axis that you want to configure.
  4. In the Tuning Options toolbar, configure the Excitation Time (ms) and the Percent Average Current.
  5. In the Calculation Options toolbar, enter a target Crossover Frequency (Hz) and Phase Margin (deg).

    6. Tip: For information about applicable target values for a range of mechanical devices, refer to the Selecting a Maximum Target Crossover Frequency section of this guide. A phase margin in the range of 32 degrees to 45 degrees is permitted for most conditions.

  6. Click the Start Open Loop Tuning button .
  7. If the Open Loop Tuning tool tells you that an invalid inertia was calculated, multiply the Excitation Time (ms) or the Percent Average Current by two. Then click the Start Open Loop Tuning button to do Open Loop Tuning again.
  8. If the quality estimate is less than 50%, do not apply these changes. Increase the values of the Excitation Time (ms) and the Percent Average Current. Then click the Start Open Loop Tuning button to do Open Loop Tuning again.
  9. To apply the servo parameter values to the controller, click the Apply Changes button.
  10. If the axis is stable when the new servo parameter values are applied, Aerotech recommends that you use a different tuning tool that keeps the axis under closed-loop control, such as Closed LoopClosed A broad term relating to any system where the output is measured and compared to the input. Output is adjusted to reach the desired condition. Tuning or the Frequency Response module.

Related Help Pages 

Servo Topic

Axes Category Overview