Position Control VBL2360

6 years 1 month ago #29529642 by rajeshwar
I am trying to control BLDC motors in position as well as in speed mode. Feedback sensor for speed control is inbuilt Hall sensors and for position feedback, I have installed potentiometer.

Problem with position control is that when the actuator reaches its desired position, the motor is still humming. In Roborun application software I can clearly see the Hall speed parameter varying. I tried changing the dead band , and P, I, D parameters. The transition is smooth however, the when it reaches its destination, motor keeps on vibrating.


In speed control mode, when I give command from Roborun software, the motors starts to rotate at full speed and then stops after 1 second and then it again starts rotating with full speed. This cycle continues till I power off the controller. The motor is running fine in open loop mode.

Thanks,
Rajeshwar

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6 years 1 month ago #29529643 by Griffin Baker
Replied by Griffin Baker on topic Position Control VBL2360
If it is vibrating, then most likely the issue is with the tuning. If you go into the "run" tab, can you do the following?

Set some channels in the bottom right area of the browser.

Motor command
motor power
hall speed

and then give the motor a command that allows the condition to appear. Then stop the command. At the bottom is a save to disk button. Please save the file and upload here via a compressed folder as the upload file without being zipped first seems to be a problem.

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6 years 1 month ago #29529663 by rajeshwar
Replied by rajeshwar on topic Position Control VBL2360
pls find the log file attached.

What could be possible reason for closed loop speed control mode not operating in desired way?

File Attachment:

File Name: ChartLog_D4J1.zip
File Size:4 KB
Attachments:

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6 years 1 month ago #29529664 by TechSupport
The PID definitely appears like it isn't tuned. I see a bunch of oscillations.

In the position mode, you need to adjust your P gain first to where it moves to the position as close as it can without oscillations. Then you add in a little I gain so that it tries to reach the desired position. At that point if it starts to oscillate, you can reduce the integrator limit as it will reduce the integrator output down to x% over the sum of the error.

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6 years 1 month ago #29529665 by rajeshwar
Replied by rajeshwar on topic Position Control VBL2360
I tried different values of P, I and D values. You have suggested to change values of P, I and integrator limit. How about changing value of D?.
What should be initial values of P, I, D and integrator limit parameters?

I am still struggling to control the motor in closed loop speed control mode. Can you help me in that too please.

Thanks

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6 years 1 month ago - 6 years 1 month ago #29529666 by TechSupport
In speed mode, you work with the I gain parameter. Add just enough so that it gets close to the desired speed as possible without oscillations. You add in a small amount of D gain for the extra boost. You add in small P gain to allow it to get to the desired speed. Leave the integrator alone in this mode, since it runs primarily on that.

Also, what is the firmware date you are using? In the console tab, send in this command. ?fid

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6 years 1 month ago #29529668 by rajeshwar
Replied by rajeshwar on topic Position Control VBL2360
What should be initial values of P, I, D and integrator limit parameters in position control mode?

I have updated the drives with latest firmware.

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6 years 1 month ago #29529669 by TechSupport
Start with something low for you I gain and 0 for all other gains. Then increase as you see fit.

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