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RE: [Paparazzi-devel] Reply to "How to adjust surface travel and throttl


From: Edixon Giraldo
Subject: RE: [Paparazzi-devel] Reply to "How to adjust surface travel and throttle? (Edixon Giraldo)"
Date: Tue, 17 Aug 2010 10:00:30 -0500

This is a great explanation Chris.  Thank you very much.  Let me just clarify, I take off in MANUAL and switch to AUTO1 high enough.  Do I launch the A/C in the GCS, or, am I just switching to AUTO1 and controling with the radio to check the roll and pitch angles?  I already see from the commands in the aircraft.xml that I don't have the same section for the AUTO1 as you mentioned.  I need to correct that.  Maybe that would make things better.
 
The section:
 
 <define name="HORIZ_SENSOR_TILTED" value="1"/>
 <define name="LATERAL_CORRECTION" value="1.0"/>
 <define name="LONGITUDINAL_CORRECTION" value="1.0"/>
 <define name="VERTICAL_CORRECTION" value="1.5"/>

calibrates the PFD to actual angles, correct?  I am just making sure that is what I understood.
 
How about the throttle part?  How do I match the throttle of Auto2 to that of manual and Auto1 to maintain cruise speed?
 
Thanks.
 
Eddie.
 
> Date: Tue, 17 Aug 2010 17:35:37 +0300
> From: address@hidden
> To: address@hidden
> Subject: [Paparazzi-devel] Reply to "How to adjust surface travel and throttle? (Edixon Giraldo)"
>
> I always hand launch in auto2 without a single failure until now.
> What i simply do is in the early stages of tuning to fly manual first
> and engage AUTO1 high
> enough in order to see if the plane turns as expected.
> In the airframe file there is a section that defines the maximum bank
> angles in AUTO1
> <section name="AUTO1" prefix="AUTO1_">
> <define name="MAX_ROLL" value="RadOfDeg(45)"/>
> <define name="MAX_PITCH" value="RadOfDeg(45)"/>
> </section>
> and i always make sure that i can achieve those during AUTO1 flight.
>
> If i can't then the PFD is not showing the actual pitch and roll angles
> because the
> <define name="HORIZ_SENSOR_TILTED" value="1"/>
> <define name="LATERAL_CORRECTION" value="1.0"/>
> <define name="LONGITUDINAL_CORRECTION" value="1.0"/>
> <define name="VERTICAL_CORRECTION" value="1.5"/>
> need to be adjusted.
>
> You can also adjust each side alone using those definitions:
> <define name="CORRECTION_UP" value="1."/>
> <define name="CORRECTION_DOWN" value="1."/>
> <define name="CORRECTION_LEFT" value="1."/>
> <define name="CORRECTION_RIGHT" value="1."/>
>
> Then after i achieve correct roll and pitch indications i increase the
> roll and pitch gains until
> the oscillations just begin.
> Finally i decrease the gain 500 units from where the oscilations begin.
> For example if the oscillations start at a gain of -7500 then i set the
> gain at -7000.
> Those gains mainly affect the servo movement when you roll and/or pitch
> the aircraft
> as the calculate the servo movement from the angle error.
> For example if the wind has forced the plane to roll -10 degrees (to the
> left, positive is to the right)
> then the autopilot will calculate that it needs to change the aileron
> servo pulse width from 1500 to 1600 with a gain of -5000 and to 1700 if
> the gain is set to -10000!!!
> I hope i made that clear.
> This of course will only work if the -10 degrees the autopilot sees are
> indeed -10 degrees and not -20
> because your PFD indications are in error.
> To make things worst if you use slow servos you will find that the
> minimum needed gain induces oscillation where if you have used fast
> servos (0.1ms or lower) you could increase the gain even more.
> A slow servo will take more time to get to the desired angle and until
> it reaches it's position
> the autopilot sees that the plane is not responding well and commands
> more servo travel.
> When the servo finally reaches the commanded angle the plane has started
> to roll to the opposite side
> due to over correction and the autopilot commands an opposite servo
> movement only to overshoot again and the oscillation start.
> Chris
>
>
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