Hi everyone,

I’m an engineer with Teknic and I ran across your thread. I just wanted to comment on some statements that have been made and provide some support recommendations.

ClearPath is a high performance servo drive integrated with an 8-pole, 3 phase brushless servo motor with encoder. It is designed, built, and supported in the USA. When the motor is properly tuned for your load and mechanics, it should not feel “spongy”.

As bobmagnuson mentioned, you can get an idea of the performance you should be getting by watching the YouTube video he recommended (https://youtu.be/n33fCmUu9A8?t=875) where a guy using ClearPath on a CNC machine demonstrates the disturbance rejection.

If you look at the ClearPath diagnostic display, you’ll see that by leaning hard into the gantry, he only deflects the servo motor about 40-50 counts. (That deflection amounts to about 2.8 degrees on the motor shaft on the model he is using. The rest of the movement you see is compliance in the mechanics.)

Our experience is that the auto-tuner does a good job creating a robust motor file for over 90% of automated applications. That said, it is very difficult to create an algorithm that can perfectly automate this complex process every single time. An automation engineer has the advantage of being able to look at the mechanical design and listen to the customer describe the application objectives in order to create the appropriate tuning file.

In order for the auto-tuner to create a tuning file, it has to create motion and then look at the resulting encoder and torque data. This data is analyzed using FFT analysis and adjustments are made to the various gains up and down in an effort to optimize objectives such as low tracking error, quick settling, and minimal vibration. Sometimes a compromise needs to be made between factors such as audible noise and stiffness due to details like reflected inertia and the mechanical design.

Fortunately, we have a path for users to follow to help optimize performance:

1. MSP Fine Tuning: In MSP under Setup/Tuning/Fine Tuning, you can select “Apply Fine Tuning” and adjust the slider bar. If your axis appears to be “spongy”, you can move the slider bar to the right (or “stiffer” side). If the axis is stiff enough but has some audible noise, you can move the slider bar to the left (or “quieter” side).

2. Re-run Auto-tune: In MSP go to File/Save Configuration File and save your existing motor file (.mtr file) with a unique name. This will ensure that you can revert to the existing tuning file if needed. Then make sure that the axis is fully loaded for the worst case load scenario (e.g. if your load varies between 120-160 lbs, use 160 lbs). Make sure that the load is fully secured. Run the auto-tuner again. During the auto-tuning process, check to see if you have limited the torque of the motor. Limiting the torque can negatively affect the results of the auto-tuning process. Now repeat the tuning process and after the auto-tuner has finished running, adjust the “Fine-Tuning” slider if needed.

3. Free Direct Support: If you are still not getting the performance that you expected, you can always contact Teknic for factory direct support. Our engineers will discuss your application design and performance objectives with you and then use advanced manual tuning techniques to help optimize the tuning file.
If you have additional questions or need technical support, please give us a call at 585-784-7454 between 8AM-6PM EST, or use the "Contact Us" form on Teknic’s website:

https://www.teknic.com/contact/

Best,

Aaron B. - Teknic Servo Systems Engineer