Re: Plane drops after take off on energyadaptative loop

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Re: Plane drops after take off on energyadaptative loop

Tobias
Hi Joseph,

energy-loop is the way to go, just to answer your last question. :-)

regarding the unwonted behavior - first thing to check is: is your airframe well tuned? I mean is it holding altitude and speed well. after a wile?
If so you should check probably the values for ( ) against the flight log for straight flight and climb.
<!-- auto throttle inner loop -->
<define name="AUTO_THROTTLE_NOMINAL_CRUISE_THROTTLE" value="0.3"/>
<define name="AUTO_THROTTLE_NOMINAL_CRUISE_PITCH" value="0."/> <!-- default 0 -->
<define name="AUTO_THROTTLE_CLIMB_THROTTLE_INCREMENT" value="0.1" unit="%/(m/s)"/>


in the scenario you described you are changing from fixed values to the energy loop - its always a good idea to have the plane in a rather similar attitude/speed to do this. So what is your alt for stby? just thing about it - if it is the same alt as your deroute from the previous block try to increase the stby alt or decrease the deroute alt 
      <exception cond="GetPosAlt() > ground_alt+50" deroute="Standby"/>

this allows the plane to catch up.

cheers Tobi

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Re: Plane drops after take off on energyadaptative loop

Christophe De Wagter

Fill the nominal cruise pitch (about 20 to 25 degrees) into the nominal cruise pitch: RadOfDeg(25)

PS: your cruise pitch looks quite large. Might want to look at the tuning of your inner loop, the placement of your IMU etc...

On Feb 23, 2016 20:56, "Tobias" <[hidden email]> wrote:
Hi Joseph,

energy-loop is the way to go, just to answer your last question. :-)

regarding the unwonted behavior - first thing to check is: is your airframe well tuned? I mean is it holding altitude and speed well. after a wile?
If so you should check probably the values for ( ) against the flight log for straight flight and climb.
<!-- auto throttle inner loop -->
<define name="AUTO_THROTTLE_NOMINAL_CRUISE_THROTTLE" value="0.3"/>
<define name="AUTO_THROTTLE_NOMINAL_CRUISE_PITCH" value="0."/> <!-- default 0 -->
<define name="AUTO_THROTTLE_CLIMB_THROTTLE_INCREMENT" value="0.1" unit="%/(m/s)"/>


in the scenario you described you are changing from fixed values to the energy loop - its always a good idea to have the plane in a rather similar attitude/speed to do this. So what is your alt for stby? just thing about it - if it is the same alt as your deroute from the previous block try to increase the stby alt or decrease the deroute alt 
      <exception cond="GetPosAlt() > ground_alt+50" deroute="Standby"/>

this allows the plane to catch up.

cheers Tobi

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Re: Plane drops after take off on energyadaptative loop

Christophe De Wagter

It takes a few moments for the integrator to find out you need a 20 degree pitch up to stay level, which explains the sudden dive followed by normal flight. As default value for the pitch integrator the cruise pitch from the airframe file is used.

On Feb 24, 2016 01:53, "Christophe De Wagter" <[hidden email]> wrote:

Fill the nominal cruise pitch (about 20 to 25 degrees) into the nominal cruise pitch: RadOfDeg(25)

PS: your cruise pitch looks quite large. Might want to look at the tuning of your inner loop, the placement of your IMU etc...

On Feb 23, 2016 20:56, "Tobias" <[hidden email]> wrote:
Hi Joseph,

energy-loop is the way to go, just to answer your last question. :-)

regarding the unwonted behavior - first thing to check is: is your airframe well tuned? I mean is it holding altitude and speed well. after a wile?
If so you should check probably the values for ( ) against the flight log for straight flight and climb.
<!-- auto throttle inner loop -->
<define name="AUTO_THROTTLE_NOMINAL_CRUISE_THROTTLE" value="0.3"/>
<define name="AUTO_THROTTLE_NOMINAL_CRUISE_PITCH" value="0."/> <!-- default 0 -->
<define name="AUTO_THROTTLE_CLIMB_THROTTLE_INCREMENT" value="0.1" unit="%/(m/s)"/>


in the scenario you described you are changing from fixed values to the energy loop - its always a good idea to have the plane in a rather similar attitude/speed to do this. So what is your alt for stby? just thing about it - if it is the same alt as your deroute from the previous block try to increase the stby alt or decrease the deroute alt 
      <exception cond="GetPosAlt() > ground_alt+50" deroute="Standby"/>

this allows the plane to catch up.

cheers Tobi

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Re: Plane drops after take off on energyadaptative loop

josibarns
Tobias, thanks! my plane is tuned pitch down to make landing easier, I will modify that. The standby waypoint in 50 m above the deroute.

Christophe, thanks! Yes my nominal pitch is high because I fly really close to stall speed and thus need a high angle of attack. Could I instead increase the nominal throttle and fly with a pitch near 0?

Best,
Joseph

On Tue, Feb 23, 2016 at 12:57 PM, Christophe De Wagter <[hidden email]> wrote:

It takes a few moments for the integrator to find out you need a 20 degree pitch up to stay level, which explains the sudden dive followed by normal flight. As default value for the pitch integrator the cruise pitch from the airframe file is used.

On Feb 24, 2016 01:53, "Christophe De Wagter" <[hidden email]> wrote:

Fill the nominal cruise pitch (about 20 to 25 degrees) into the nominal cruise pitch: RadOfDeg(25)

PS: your cruise pitch looks quite large. Might want to look at the tuning of your inner loop, the placement of your IMU etc...

On Feb 23, 2016 20:56, "Tobias" <[hidden email]> wrote:
Hi Joseph,

energy-loop is the way to go, just to answer your last question. :-)

regarding the unwonted behavior - first thing to check is: is your airframe well tuned? I mean is it holding altitude and speed well. after a wile?
If so you should check probably the values for ( ) against the flight log for straight flight and climb.
<!-- auto throttle inner loop -->
<define name="AUTO_THROTTLE_NOMINAL_CRUISE_THROTTLE" value="0.3"/>
<define name="AUTO_THROTTLE_NOMINAL_CRUISE_PITCH" value="0."/> <!-- default 0 -->
<define name="AUTO_THROTTLE_CLIMB_THROTTLE_INCREMENT" value="0.1" unit="%/(m/s)"/>


in the scenario you described you are changing from fixed values to the energy loop - its always a good idea to have the plane in a rather similar attitude/speed to do this. So what is your alt for stby? just thing about it - if it is the same alt as your deroute from the previous block try to increase the stby alt or decrease the deroute alt 
      <exception cond="GetPosAlt() > ground_alt+50" deroute="Standby"/>

this allows the plane to catch up.

cheers Tobi

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Re: Plane drops after take off on energyadaptative loop

Christophe De Wagter

If the high pitch angle is fine for you, just type the desired-pitch value you see during normal cruise as nominal cruise pitch in your airframe file. Otherwise your controller will start with this value (in your case about 20 deg) too little pitch and it takes a few seconds for the controller to correct such a big angle, especially when you activate it in (slight) underspeed, in which the initial reaction is to slightly nose down a few degrees extra before it finally notices the dramatic dive and starts to correct for this using the diff i  gain.

Nominal-cruise-pitch is  used as initial value for energy control. Put a reasonable value in there ( in your case RadOfDeg(22) linking at your graphs )

On Feb 24, 2016 02:17, "Joseph Muhlhausen" <[hidden email]> wrote:
Tobias, thanks! my plane is tuned pitch down to make landing easier, I will modify that. The standby waypoint in 50 m above the deroute.

Christophe, thanks! Yes my nominal pitch is high because I fly really close to stall speed and thus need a high angle of attack. Could I instead increase the nominal throttle and fly with a pitch near 0?

Best,
Joseph

On Tue, Feb 23, 2016 at 12:57 PM, Christophe De Wagter <[hidden email]> wrote:

It takes a few moments for the integrator to find out you need a 20 degree pitch up to stay level, which explains the sudden dive followed by normal flight. As default value for the pitch integrator the cruise pitch from the airframe file is used.

On Feb 24, 2016 01:53, "Christophe De Wagter" <[hidden email]> wrote:

Fill the nominal cruise pitch (about 20 to 25 degrees) into the nominal cruise pitch: RadOfDeg(25)

PS: your cruise pitch looks quite large. Might want to look at the tuning of your inner loop, the placement of your IMU etc...

On Feb 23, 2016 20:56, "Tobias" <[hidden email]> wrote:
Hi Joseph,

energy-loop is the way to go, just to answer your last question. :-)

regarding the unwonted behavior - first thing to check is: is your airframe well tuned? I mean is it holding altitude and speed well. after a wile?
If so you should check probably the values for ( ) against the flight log for straight flight and climb.
<!-- auto throttle inner loop -->
<define name="AUTO_THROTTLE_NOMINAL_CRUISE_THROTTLE" value="0.3"/>
<define name="AUTO_THROTTLE_NOMINAL_CRUISE_PITCH" value="0."/> <!-- default 0 -->
<define name="AUTO_THROTTLE_CLIMB_THROTTLE_INCREMENT" value="0.1" unit="%/(m/s)"/>


in the scenario you described you are changing from fixed values to the energy loop - its always a good idea to have the plane in a rather similar attitude/speed to do this. So what is your alt for stby? just thing about it - if it is the same alt as your deroute from the previous block try to increase the stby alt or decrease the deroute alt 
      <exception cond="GetPosAlt() > ground_alt+50" deroute="Standby"/>

this allows the plane to catch up.

cheers Tobi

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Re: Plane drops after take off on energyadaptative loop

Balázs GÁTI
Dear Joseph!

Flying close to the stall speed is not the safest way of operation,
because the aerodynamic behavior of the airplane changes very
non-linear. Thus the controller won't be able to keep the demanded
altitude, speed, AoA, as you would expect.

Of course UAV is the best device to research stall but I suppose you
don't like it during take-off. :)

Balazs




2016.02.23. 21:57 keltezéssel, Christophe De Wagter írta:

> If the high pitch angle is fine for you, just type the desired-pitch
> value you see during normal cruise as nominal cruise pitch in your
> airframe file. Otherwise your controller will start with this value (in
> your case about 20 deg) too little pitch and it takes a few seconds for
> the controller to correct such a big angle, especially when you activate
> it in (slight) underspeed, in which the initial reaction is to slightly
> nose down a few degrees extra before it finally notices the dramatic
> dive and starts to correct for this using the diff i  gain.
>
> Nominal-cruise-pitch is  used as initial value for energy control. Put a
> reasonable value in there ( in your case RadOfDeg(22) linking at your
> graphs )
>
> On Feb 24, 2016 02:17, "Joseph Muhlhausen" <[hidden email]
> <mailto:[hidden email]>> wrote:
>
>     Tobias, thanks! my plane is tuned pitch down to make landing easier,
>     I will modify that. The standby waypoint in 50 m above the deroute.
>
>     Christophe, thanks! Yes my nominal pitch is high because I fly
>     really close to stall speed and thus need a high angle of attack.
>     Could I instead increase the nominal throttle and fly with a pitch
>     near 0?
>
>     Best,
>     Joseph
>
>     On Tue, Feb 23, 2016 at 12:57 PM, Christophe De Wagter
>     <[hidden email] <mailto:[hidden email]>> wrote:
>
>         It takes a few moments for the integrator to find out you need a
>         20 degree pitch up to stay level, which explains the sudden dive
>         followed by normal flight. As default value for the pitch
>         integrator the cruise pitch from the airframe file is used.
>
>         On Feb 24, 2016 01:53, "Christophe De Wagter"
>         <[hidden email] <mailto:[hidden email]>> wrote:
>
>             Fill the nominal cruise pitch (about 20 to 25 degrees) into
>             the nominal cruise pitch: RadOfDeg(25)
>
>             PS: your cruise pitch looks quite large. Might want to look
>             at the tuning of your inner loop, the placement of your IMU
>             etc...
>
>             On Feb 23, 2016 20:56, "Tobias" <[hidden email]
>             <mailto:[hidden email]>> wrote:
>
>                 Hi Joseph,
>
>                 energy-loop is the way to go, just to answer your last
>                 question. :-)
>
>                 regarding the unwonted behavior - first thing to check
>                 is: is your airframe well tuned? I mean is it holding
>                 altitude and speed well. after a wile?
>                 If so you should check probably the values for ( )
>                 against the flight log for straight flight and climb.
>                 <!-- auto throttle inner loop -->
>                 <define name="AUTO_THROTTLE_NOMINAL_CRUISE_THROTTLE"
>                 value="0.3"/>
>                 <define name="AUTO_THROTTLE_NOMINAL_CRUISE_PITCH"
>                 value="0."/> <!-- default 0 -->
>                 <define name="AUTO_THROTTLE_CLIMB_THROTTLE_INCREMENT"
>                 value="0.1" unit="%/(m/s)"/>
>
>
>
>                 in the scenario you described you are changing from
>                 fixed values to the energy loop - its always a good idea
>                 to have the plane in a rather similar attitude/speed to
>                 do this. So what is your alt for stby? just thing about
>                 it - if it is the same alt as your deroute from the
>                 previous block try to increase the stby alt or decrease
>                 the deroute alt
>                        <exception cond="GetPosAlt() > ground_alt+50"
>                 deroute="Standby"/>
>
>                 this allows the plane to catch up.
>
>                 cheers Tobi
>
>                 _______________________________________________
>                 Paparazzi-devel mailing list
>                 [hidden email]
>                 <mailto:[hidden email]>
>                 https://lists.nongnu.org/mailman/listinfo/paparazzi-devel
>
>
>         _______________________________________________
>         Paparazzi-devel mailing list
>         [hidden email] <mailto:[hidden email]>
>         https://lists.nongnu.org/mailman/listinfo/paparazzi-devel
>
>
>
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>     Paparazzi-devel mailing list
>     [hidden email] <mailto:[hidden email]>
>     https://lists.nongnu.org/mailman/listinfo/paparazzi-devel
>
>
>
> _______________________________________________
> Paparazzi-devel mailing list
> [hidden email]
> https://lists.nongnu.org/mailman/listinfo/paparazzi-devel
>

--
Balazs GATI, PhD
associate professor
      Department of Aeronautics, Naval Architecture and Railway Vehicles
      Budapest University of Technology and Economics

Address:   Budapest
           Stoczek u 6. J. ép. 423
           1111
Tel:       +(36)-1-463-1960
Fax:       +(36)-1-463-3080
Homepage: http://vrht.bme.hu/

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Re: Plane drops after take off on energyadaptative loop

josibarns
Thanks Guys!

It looks like I am flying too slowly, I honestly thought the AoA was around 5 degree and didn't think of checking the log. I will test the plane again this weekend with your recommendations and report.

Joseph

On Wed, Feb 24, 2016 at 2:29 AM, Balazs GATI <[hidden email]> wrote:
Dear Joseph!

Flying close to the stall speed is not the safest way of operation, because the aerodynamic behavior of the airplane changes very non-linear. Thus the controller won't be able to keep the demanded altitude, speed, AoA, as you would expect.

Of course UAV is the best device to research stall but I suppose you don't like it during take-off. :)

Balazs




<a href="tel:2016.02.23.%2021" value="+12016022321" target="_blank">2016.02.23. 21:57 keltezéssel, Christophe De Wagter írta:
If the high pitch angle is fine for you, just type the desired-pitch
value you see during normal cruise as nominal cruise pitch in your
airframe file. Otherwise your controller will start with this value (in
your case about 20 deg) too little pitch and it takes a few seconds for
the controller to correct such a big angle, especially when you activate
it in (slight) underspeed, in which the initial reaction is to slightly
nose down a few degrees extra before it finally notices the dramatic
dive and starts to correct for this using the diff i  gain.

Nominal-cruise-pitch is  used as initial value for energy control. Put a
reasonable value in there ( in your case RadOfDeg(22) linking at your
graphs )

On Feb 24, 2016 02:17, "Joseph Muhlhausen" <[hidden email]
<mailto:[hidden email]>> wrote:

    Tobias, thanks! my plane is tuned pitch down to make landing easier,
    I will modify that. The standby waypoint in 50 m above the deroute.

    Christophe, thanks! Yes my nominal pitch is high because I fly
    really close to stall speed and thus need a high angle of attack.
    Could I instead increase the nominal throttle and fly with a pitch
    near 0?

    Best,
    Joseph

    On Tue, Feb 23, 2016 at 12:57 PM, Christophe De Wagter
    <[hidden email] <mailto:[hidden email]>> wrote:

        It takes a few moments for the integrator to find out you need a
        20 degree pitch up to stay level, which explains the sudden dive
        followed by normal flight. As default value for the pitch
        integrator the cruise pitch from the airframe file is used.

        On Feb 24, 2016 01:53, "Christophe De Wagter"
        <[hidden email] <mailto:[hidden email]>> wrote:

            Fill the nominal cruise pitch (about 20 to 25 degrees) into
            the nominal cruise pitch: RadOfDeg(25)

            PS: your cruise pitch looks quite large. Might want to look
            at the tuning of your inner loop, the placement of your IMU
            etc...

            On Feb 23, 2016 20:56, "Tobias" <[hidden email]
            <mailto:[hidden email]>> wrote:

                Hi Joseph,

                energy-loop is the way to go, just to answer your last
                question. :-)

                regarding the unwonted behavior - first thing to check
                is: is your airframe well tuned? I mean is it holding
                altitude and speed well. after a wile?
                If so you should check probably the values for ( )
                against the flight log for straight flight and climb.
                <!-- auto throttle inner loop -->
                        <define name="AUTO_THROTTLE_NOMINAL_CRUISE_THROTTLE"
                value="0.3"/>
                        <define name="AUTO_THROTTLE_NOMINAL_CRUISE_PITCH"
                value="0."/> <!-- default 0 -->
                        <define name="AUTO_THROTTLE_CLIMB_THROTTLE_INCREMENT"
                value="0.1" unit="%/(m/s)"/>



                in the scenario you described you are changing from
                fixed values to the energy loop - its always a good idea
                to have the plane in a rather similar attitude/speed to
                do this. So what is your alt for stby? just thing about
                it - if it is the same alt as your deroute from the
                previous block try to increase the stby alt or decrease
                the deroute alt
                       <exception cond="GetPosAlt() > ground_alt+50"
                deroute="Standby"/>

                this allows the plane to catch up.

                cheers Tobi

                _______________________________________________
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--
Balazs GATI, PhD
associate professor
     Department of Aeronautics, Naval Architecture and Railway Vehicles
     Budapest University of Technology and Economics

Address:   Budapest
          Stoczek u 6. J. ép. 423
          1111
Tel:       <a href="tel:%2B%2836%29-1-463-1960" value="+3614631960" target="_blank">+(36)-1-463-1960
Fax:       <a href="tel:%2B%2836%29-1-463-3080" value="+3614633080" target="_blank">+(36)-1-463-3080
Homepage: http://vrht.bme.hu/


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Re: Plane drops after take off on energyadaptative loop

josibarns
Just to report, I re-trimmed the plane and re-tuned the pitch loop, I also increase the initial nominal cruise pitch to 1 degree and played with the energy total and energy diff gains, it seems to have solved the issue.

Thanks again!



On Wed, Feb 24, 2016 at 10:51 AM, Joseph Muhlhausen <[hidden email]> wrote:
Thanks Guys!

It looks like I am flying too slowly, I honestly thought the AoA was around 5 degree and didn't think of checking the log. I will test the plane again this weekend with your recommendations and report.

Joseph

On Wed, Feb 24, 2016 at 2:29 AM, Balazs GATI <[hidden email]> wrote:
Dear Joseph!

Flying close to the stall speed is not the safest way of operation, because the aerodynamic behavior of the airplane changes very non-linear. Thus the controller won't be able to keep the demanded altitude, speed, AoA, as you would expect.

Of course UAV is the best device to research stall but I suppose you don't like it during take-off. :)

Balazs




<a href="tel:2016.02.23.%2021" value="+12016022321" target="_blank">2016.02.23. 21:57 keltezéssel, Christophe De Wagter írta:
If the high pitch angle is fine for you, just type the desired-pitch
value you see during normal cruise as nominal cruise pitch in your
airframe file. Otherwise your controller will start with this value (in
your case about 20 deg) too little pitch and it takes a few seconds for
the controller to correct such a big angle, especially when you activate
it in (slight) underspeed, in which the initial reaction is to slightly
nose down a few degrees extra before it finally notices the dramatic
dive and starts to correct for this using the diff i  gain.

Nominal-cruise-pitch is  used as initial value for energy control. Put a
reasonable value in there ( in your case RadOfDeg(22) linking at your
graphs )

On Feb 24, 2016 02:17, "Joseph Muhlhausen" <[hidden email]
<mailto:[hidden email]>> wrote:

    Tobias, thanks! my plane is tuned pitch down to make landing easier,
    I will modify that. The standby waypoint in 50 m above the deroute.

    Christophe, thanks! Yes my nominal pitch is high because I fly
    really close to stall speed and thus need a high angle of attack.
    Could I instead increase the nominal throttle and fly with a pitch
    near 0?

    Best,
    Joseph

    On Tue, Feb 23, 2016 at 12:57 PM, Christophe De Wagter
    <[hidden email] <mailto:[hidden email]>> wrote:

        It takes a few moments for the integrator to find out you need a
        20 degree pitch up to stay level, which explains the sudden dive
        followed by normal flight. As default value for the pitch
        integrator the cruise pitch from the airframe file is used.

        On Feb 24, 2016 01:53, "Christophe De Wagter"
        <[hidden email] <mailto:[hidden email]>> wrote:

            Fill the nominal cruise pitch (about 20 to 25 degrees) into
            the nominal cruise pitch: RadOfDeg(25)

            PS: your cruise pitch looks quite large. Might want to look
            at the tuning of your inner loop, the placement of your IMU
            etc...

            On Feb 23, 2016 20:56, "Tobias" <[hidden email]
            <mailto:[hidden email]>> wrote:

                Hi Joseph,

                energy-loop is the way to go, just to answer your last
                question. :-)

                regarding the unwonted behavior - first thing to check
                is: is your airframe well tuned? I mean is it holding
                altitude and speed well. after a wile?
                If so you should check probably the values for ( )
                against the flight log for straight flight and climb.
                <!-- auto throttle inner loop -->
                        <define name="AUTO_THROTTLE_NOMINAL_CRUISE_THROTTLE"
                value="0.3"/>
                        <define name="AUTO_THROTTLE_NOMINAL_CRUISE_PITCH"
                value="0."/> <!-- default 0 -->
                        <define name="AUTO_THROTTLE_CLIMB_THROTTLE_INCREMENT"
                value="0.1" unit="%/(m/s)"/>



                in the scenario you described you are changing from
                fixed values to the energy loop - its always a good idea
                to have the plane in a rather similar attitude/speed to
                do this. So what is your alt for stby? just thing about
                it - if it is the same alt as your deroute from the
                previous block try to increase the stby alt or decrease
                the deroute alt
                       <exception cond="GetPosAlt() > ground_alt+50"
                deroute="Standby"/>

                this allows the plane to catch up.

                cheers Tobi

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--
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associate professor
     Department of Aeronautics, Naval Architecture and Railway Vehicles
     Budapest University of Technology and Economics

Address:   Budapest
          Stoczek u 6. J. ép. 423
          1111
Tel:       <a href="tel:%2B%2836%29-1-463-1960" value="+3614631960" target="_blank">+(36)-1-463-1960
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Homepage: http://vrht.bme.hu/


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Re: Plane drops after take off on energyadaptative loop

flixr
Administrator
FYI, there was a bug/regression in energy_ctrl that has been fixed
now: https://github.com/paparazzi/paparazzi/pull/1597

On Fri, Mar 11, 2016 at 5:16 AM, Joseph Muhlhausen <[hidden email]> wrote:

> Just to report, I re-trimmed the plane and re-tuned the pitch loop, I also
> increase the initial nominal cruise pitch to 1 degree and played with the
> energy total and energy diff gains, it seems to have solved the issue.
>
> Thanks again!
>
>
>
> On Wed, Feb 24, 2016 at 10:51 AM, Joseph Muhlhausen <[hidden email]>
> wrote:
>>
>> Thanks Guys!
>>
>> It looks like I am flying too slowly, I honestly thought the AoA was
>> around 5 degree and didn't think of checking the log. I will test the plane
>> again this weekend with your recommendations and report.
>>
>> Joseph
>>
>> On Wed, Feb 24, 2016 at 2:29 AM, Balazs GATI <[hidden email]> wrote:
>>>
>>> Dear Joseph!
>>>
>>> Flying close to the stall speed is not the safest way of operation,
>>> because the aerodynamic behavior of the airplane changes very non-linear.
>>> Thus the controller won't be able to keep the demanded altitude, speed, AoA,
>>> as you would expect.
>>>
>>> Of course UAV is the best device to research stall but I suppose you
>>> don't like it during take-off. :)
>>>
>>> Balazs
>>>
>>>
>>>
>>>
>>> 2016.02.23. 21:57 keltezéssel, Christophe De Wagter írta:
>>>>
>>>> If the high pitch angle is fine for you, just type the desired-pitch
>>>> value you see during normal cruise as nominal cruise pitch in your
>>>> airframe file. Otherwise your controller will start with this value (in
>>>> your case about 20 deg) too little pitch and it takes a few seconds for
>>>> the controller to correct such a big angle, especially when you activate
>>>> it in (slight) underspeed, in which the initial reaction is to slightly
>>>> nose down a few degrees extra before it finally notices the dramatic
>>>> dive and starts to correct for this using the diff i  gain.
>>>>
>>>> Nominal-cruise-pitch is  used as initial value for energy control. Put a
>>>> reasonable value in there ( in your case RadOfDeg(22) linking at your
>>>> graphs )
>>>>
>>>> On Feb 24, 2016 02:17, "Joseph Muhlhausen" <[hidden email]
>>>> <mailto:[hidden email]>> wrote:
>>>>
>>>>     Tobias, thanks! my plane is tuned pitch down to make landing easier,
>>>>     I will modify that. The standby waypoint in 50 m above the deroute.
>>>>
>>>>     Christophe, thanks! Yes my nominal pitch is high because I fly
>>>>     really close to stall speed and thus need a high angle of attack.
>>>>     Could I instead increase the nominal throttle and fly with a pitch
>>>>     near 0?
>>>>
>>>>     Best,
>>>>     Joseph
>>>>
>>>>     On Tue, Feb 23, 2016 at 12:57 PM, Christophe De Wagter
>>>>     <[hidden email] <mailto:[hidden email]>> wrote:
>>>>
>>>>         It takes a few moments for the integrator to find out you need a
>>>>         20 degree pitch up to stay level, which explains the sudden dive
>>>>         followed by normal flight. As default value for the pitch
>>>>         integrator the cruise pitch from the airframe file is used.
>>>>
>>>>         On Feb 24, 2016 01:53, "Christophe De Wagter"
>>>>         <[hidden email] <mailto:[hidden email]>> wrote:
>>>>
>>>>             Fill the nominal cruise pitch (about 20 to 25 degrees) into
>>>>             the nominal cruise pitch: RadOfDeg(25)
>>>>
>>>>             PS: your cruise pitch looks quite large. Might want to look
>>>>             at the tuning of your inner loop, the placement of your IMU
>>>>             etc...
>>>>
>>>>             On Feb 23, 2016 20:56, "Tobias" <[hidden email]
>>>>             <mailto:[hidden email]>> wrote:
>>>>
>>>>                 Hi Joseph,
>>>>
>>>>                 energy-loop is the way to go, just to answer your last
>>>>                 question. :-)
>>>>
>>>>                 regarding the unwonted behavior - first thing to check
>>>>                 is: is your airframe well tuned? I mean is it holding
>>>>                 altitude and speed well. after a wile?
>>>>                 If so you should check probably the values for ( )
>>>>                 against the flight log for straight flight and climb.
>>>>                 <!-- auto throttle inner loop -->
>>>>                         <define
>>>> name="AUTO_THROTTLE_NOMINAL_CRUISE_THROTTLE"
>>>>                 value="0.3"/>
>>>>                         <define
>>>> name="AUTO_THROTTLE_NOMINAL_CRUISE_PITCH"
>>>>                 value="0."/> <!-- default 0 -->
>>>>                         <define
>>>> name="AUTO_THROTTLE_CLIMB_THROTTLE_INCREMENT"
>>>>                 value="0.1" unit="%/(m/s)"/>
>>>>
>>>>
>>>>
>>>>                 in the scenario you described you are changing from
>>>>                 fixed values to the energy loop - its always a good idea
>>>>                 to have the plane in a rather similar attitude/speed to
>>>>                 do this. So what is your alt for stby? just thing about
>>>>                 it - if it is the same alt as your deroute from the
>>>>                 previous block try to increase the stby alt or decrease
>>>>                 the deroute alt
>>>>                        <exception cond="GetPosAlt() > ground_alt+50"
>>>>                 deroute="Standby"/>
>>>>
>>>>                 this allows the plane to catch up.
>>>>
>>>>                 cheers Tobi
>>>>
>>>>                 _______________________________________________
>>>>                 Paparazzi-devel mailing list
>>>>                 [hidden email]
>>>>                 <mailto:[hidden email]>
>>>>
>>>> https://lists.nongnu.org/mailman/listinfo/paparazzi-devel
>>>>
>>>>
>>>>         _______________________________________________
>>>>         Paparazzi-devel mailing list
>>>>         [hidden email] <mailto:[hidden email]>
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>>>>
>>>>
>>>>
>>>>     _______________________________________________
>>>>     Paparazzi-devel mailing list
>>>>     [hidden email] <mailto:[hidden email]>
>>>>     https://lists.nongnu.org/mailman/listinfo/paparazzi-devel
>>>>
>>>>
>>>>
>>>> _______________________________________________
>>>> Paparazzi-devel mailing list
>>>> [hidden email]
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>>>>
>>>
>>> --
>>> Balazs GATI, PhD
>>> associate professor
>>>      Department of Aeronautics, Naval Architecture and Railway Vehicles
>>>      Budapest University of Technology and Economics
>>>
>>> Address:   Budapest
>>>           Stoczek u 6. J. ép. 423
>>>           1111
>>> Tel:       +(36)-1-463-1960
>>> Fax:       +(36)-1-463-3080
>>> Homepage: http://vrht.bme.hu/
>>>
>>>
>>> _______________________________________________
>>> Paparazzi-devel mailing list
>>> [hidden email]
>>> https://lists.nongnu.org/mailman/listinfo/paparazzi-devel
>>
>>
>
>
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