MikeNH

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"Zero the integral when throttle is low" (Wizard bug?)
« on: October 30, 2017, 12:36:55 am »
For months my quad with Revolution FC and GCS 16.09 has been suddenly surging and leaping either into the air uncontrollably or flipping on takeoff. I've done lots of searches on these symptoms and have seen the common solutions but the problem persisted UNTIL I saw posts indicating that "Zero the integral when throttle is low" should be checked (enabled).  This setting is on the LP Stabilization page.

Once I enabled this, the quad took off beautifully under complete control because the throttle was able to be increased gradually.

Posts indicate that this setting should be enabled by default. Mine was not and I didn't touch it. After enabling it, I ran through the vehicle and transmitter setup and found that it was again disabled (unchecked). Bug?

Before retesting this, I wanted to see if there has been a bug reported on this issue. If there isn't, I will reconfirm this behavior and create the "steps to recreate" the problem. I can't find where the list of bugs are or instructions on creating a bug report. I think because we are encouraged to participate, instructions creating a bug report should be easy to find. Where am I going wrong? I've looked at GitHub and BitBucket. To create or search for bug reports is not obvious.

Please point me to where I can search for existing Librepilot bugs and create a new one if appropriate.

Thanks
« Last Edit: October 30, 2017, 12:49:24 am by MikeNH »

mr_w

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Re: "Zero the integral when throttle is low" (Wizard bug?)
« Reply #2 on: October 30, 2017, 08:44:52 pm »
The default for this is enabled.  Did you use someone else's config file?  Perhaps a template?  Maybe forgot you changed it?  :)  I have helped with this issue quite a few times in the past year and would like to know where it comes from.  :)

You get the default when you "Erase Settings", but if you import someone's UAV file all bets are off.  I also wonder about this possibly coming from an "import vehicle template".

$ grep -i integral shared/uavobjectdefinition/*
shared/uavobjectdefinition/stabilizationsettings.xml:   <field name="LowThrottleZeroIntegral" units="" type="enum" elements="1" options="False,True" defaultvalue="True"/>

f5soh

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Re: "Zero the integral when throttle is low" (Wizard bug?)
« Reply #3 on: October 30, 2017, 10:45:43 pm »

MikeNH

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Re: "Zero the integral when throttle is low" (Wizard bug?)
« Reply #4 on: October 31, 2017, 02:38:10 am »
It appears that a bug report has been created describing the cause which is beyond my understanding. If there is anything I can do, please let me know.

Mike

f5soh

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Re: "Zero the integral when throttle is low" (Wizard bug?)
« Reply #5 on: October 31, 2017, 11:51:45 am »
Quote
Some enum options like EnablePiroComp, EnableThrustPIDScaling or LowThrottleZeroIntegral are not imported correctly from templates.

In a JIRA description you do not need to describe the cause but describe the issue and steps to reproduce if something special. Most of the time we do not know the cause at start :)
The cause of badly imported True/False settings from templates is clearly identified now.

After a JIRA issue opened and some work on it, a pull request (here) is created, this PR will be reviewed/tested/approved before finally merged to current source code.

MikeNH

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Re: "Zero the integral when throttle is low" (Wizard bug?)
« Reply #6 on: November 01, 2017, 02:39:19 am »
Thank you for the process description. I will humbly make a suggestion as a solution from a complete newbee...

1 - Make the check box description less technical. Rather than "Zero the integral when throttle is low", how about "Enable to make takeoffs smoother". Then in the fly-out could have the technical description about the "I" in "PID".

2 - Put this very important feature in a prominent place on the Stabilization page rather than at the bottom where it can't be seen unless the user scrolls to the bottom.

As a new person who knew nothing, I followed the vehicle wizard instructions very closely. Those instructions include importing a template. Well, every one of the templates with a single exception, disables this significant capability.

Again, this is just the perspective of a person new to this hobby.

Thank you for a terrific application!

Mike

f5soh

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Re: "Zero the integral when throttle is low" (Wizard bug?)
« Reply #7 on: November 01, 2017, 11:08:25 am »
You can learn a lot just looking at Tooltips.
Here is the tooltip for "Zero the integral when throttle is low" :
Quote
This function will avoid integral windup when at idle. Integral windup is an accumulation of over-correction and can make the vehicle flip during a slow takeoff.

This option has not more "weight" than others in this tab.
Is at bottom because this option affect all the banks at same time.



Without the bug, this option will be enabled all times so you learned something technical at end ;)
« Last Edit: November 01, 2017, 11:11:36 am by f5soh »