Autotuning Error: Insufficient Travel Range

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Autotuning Error: Insufficient Travel Range

Postby mars_bruce_lee » Fri Dec 07, 2018 9:20 pm

Autotuning Error: Insufficient Travel Range
In the autotuning process,Often appear Autotuning Error: Insufficient Travel Range.

Since the system has a given constant voltage and the speed fluctuates, the speed is not stable.
So appear Insufficient Travel Range,Actually has nothing to do with the length of the trip
Is there such a possibility?
mars_bruce_lee
 
Posts: 210
Joined: Thu Dec 26, 2013 10:12 pm

Re: Autotuning Error: Insufficient Travel Range

Postby Jacob Paso » Mon Dec 10, 2018 8:50 am

The autotuning motion works as follows:

The Profile
For hydraulic systems or velocity mode motors, when you instruct the wizard to move the axis, it will generate an open loop voltage profile similar to that shown below. Notice that this move will not necessarily take up the entire range between the specified beginning and ending points. On many hydraulic systems, the moves takes only a couple of inches.
autotuning.png
autotuning.png (5.02 KiB) Viewed 38 times

Section A: The Control Output ramps up to the user-specified Output Voltage at the specified Ramp Rate. The Control Output stays at that value until the axis stops accelerating, at which point it goes to section B.
Section B: The Control Output ramps down to half of the user-specified Output Voltage. The Control Output stays at that value until the axis stops accelerating, at which point it goes to section C.
Section C: The Control Output ramps back up to the user-specified Output Voltage. The Control Output stays at that value until the axis stops accelerating, at which point it goes to section D.
Section D: The Control Output ramps down to zero.

Since the length of sections A, B and C depend on when the axis stops accelerating, the time of this move profile will vary from system to system. Typically, it is less than 0.5 seconds. If the Actual Position gets too close to the specified End Position at any time during the profile, the voltage will go to zero immediately. If the feedback signal is noisy, the acceleration will be noisy, and the autotuning wizard will not see that the acceleration is not settling down, so section B may take too long, and may exceed the time limit, or the position limit.

If the autotuning doesn't work, try tuning the axis with just the Proportional gain. Make sure to get plots of both directions of motion, then use the Tuning Wizard and select Use an Existing Plot.
Jacob Paso
 
Posts: 530
Joined: Thu Jan 03, 2008 3:18 pm

Re: Autotuning Error: Insufficient Travel Range

Postby mars_bruce_lee » Tue Dec 11, 2018 12:41 am

Jacob Paso wrote:The autotuning motion works as follows:

The Profile
For hydraulic systems or velocity mode motors, when you instruct the wizard to move the axis, it will generate an open loop voltage profile similar to that shown below. Notice that this move will not necessarily take up the entire range between the specified beginning and ending points. On many hydraulic systems, the moves takes only a couple of inches.
The attachment autotuning.png is no longer available

Section A: The Control Output ramps up to the user-specified Output Voltage at the specified Ramp Rate. The Control Output stays at that value until the axis stops accelerating, at which point it goes to section B.
Section B: The Control Output ramps down to half of the user-specified Output Voltage. The Control Output stays at that value until the axis stops accelerating, at which point it goes to section C.
Section C: The Control Output ramps back up to the user-specified Output Voltage. The Control Output stays at that value until the axis stops accelerating, at which point it goes to section D.
Section D: The Control Output ramps down to zero.

Since the length of sections A, B and C depend on when the axis stops accelerating, the time of this move profile will vary from system to system. Typically, it is less than 0.5 seconds. If the Actual Position gets too close to the specified End Position at any time during the profile, the voltage will go to zero immediately. If the feedback signal is noisy, the acceleration will be noisy, and the autotuning wizard will not see that the acceleration is not settling down, so section B may take too long, and may exceed the time limit, or the position limit.

If the autotuning doesn't work, try tuning the axis with just the Proportional gain. Make sure to get plots of both directions of motion, then use the Tuning Wizard and select Use an Existing Plot.


Thanks,
From the curve, the voltage has been completed according to the Profile,see below。
In theory, the voltage curve has already been completed, and it should not be warned.
Attachments
旋转补偿02_AutoTuning_01.rmcplots
Auto tuning plots
(2.81 MiB) Downloaded 2 times
截图12.png
截图12.png (35.42 KiB) Viewed 34 times
mars_bruce_lee
 
Posts: 210
Joined: Thu Dec 26, 2013 10:12 pm

Re: Autotuning Error: Insufficient Travel Range

Postby Jacob Paso » Tue Dec 11, 2018 5:11 pm

I think the last ramp-down of the Control Output was because the error occurred, rather than because the profile was complete. In any case, the plot probably has enough data to use for the autotuning. The error message is only caution, and you can continue the autotuning.

It is fairly common to do the autotuning to do an initial tuning of the system, then make moves that represent typical machine motion, and use plots from those motions to run the tuning wizard again, using existing plots. This way, you are tuning based on what the machine really does, rather than whatever motion the autotuning happens to make.
Jacob Paso
 
Posts: 530
Joined: Thu Jan 03, 2008 3:18 pm


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