Moderator

Airspeed Sensor Normal?

Hi folks,

I just installed an airspeed sensor on my new APM 2.5.. I have enabled it in mission planner and it seems to be workig well? But when I click on enable airspeed the horizon pitches up and down depending on the airspeed reading, so if I blow down the tube the artificial horizon pitches down and if in stabilize or another autopilot mode, the plane tries to compensate by raising the nose? Is this normal?

You need to be a member of diydrones to add comments!

Join diydrones

Email me when people reply –

Replies

  • It is perfectly normal for the pitch to be slightly erratic without a GPS lock while using a airspeed sensor.  You will probably notice that while the airplane is sitting still in zero wind the airspeed will jump around a few m/s.  That is because it takes very little pressure difference to change a couple m/s while near zero. Once the aircraft is above 5-10 m/s it takes a larger change in pressure to increase/decrease the speed. 

    The reason why this affects your pitch before GPS lock is because it feeds into AHRS.  I do not know all the technical terms but basically since there isn't a GPS lock it uses the airspeed to help in accelerometer/acceleration correction.  I know there are people that understand the code better than I do that could explain it, I am more familiar with Piccolo.  Bottom line is what you are seeing is normal and not a problem :)

  • Any update ?
  • I've experienced the same problem. I just bought brand new apm 2.5+ and speed sensor.:/
  • I've experienced the same problem for some time now.

  • I have the same problem. When GPS fix is obtained the problem goes away, and when GPS fix is lost, then it appears again.  If the GPS fix is lost for some reason during the flight, then the autopilot would try to stall the plane so that it would not fly far away?

  • Hi Dean.

    You right, the airspeed should not affect pitch indication but your fault rang a bell with me. Im sure I had that when I first plugged it in and I have a vague memory it was some obscure parameter. Sorry cant be more accurate.

    Have just checked it again and the horizon is not affected by blowing in but the elevator does react in auto modes (not stabilize).

    On this subject, my pitot was pissing air out everywhere when I first got it so took it apart to have a look.

    Here is my fix.

    http://diydrones.com/forum/topics/pitot-tube-question

    (on my sons I.D. – Leo Hogg).

     

    Vince

     

     

This reply was deleted.

Activity

DIY Robocars via Twitter
RT @chr1sa: Just a week to go before our next @DIYRobocars race at @circuitlaunch, complete with famous Brazilian BBQ. It's free, fun for k…
4 hours ago
DIY Robocars via Twitter
How to use the new @donkey_car graphical UI to edit driving data for better training https://www.youtube.com/watch?v=J5-zHNeNebQ
Monday
DIY Robocars via Twitter
RT @SmallpixelCar: Wrote a program to find the light positions at @circuitlaunch. Here is the hypothesis of the light locations updating ba…
Nov 26
DIY Robocars via Twitter
RT @SmallpixelCar: Broke my @HokuyoUsa Lidar today. Luckily the non-cone localization, based on @a1k0n LightSLAM idea, works. It will help…
Nov 25
DIY Robocars via Twitter
@gclue_akira CC @NVIDIAEmbedded
Nov 23
DIY Robocars via Twitter
RT @luxonis: OAK-D PoE Autonomous Vehicle (Courtesy of zonyl in our Discord: https://discord.gg/EPsZHkg9Nx) https://t.co/PNDewvJdrb
Nov 23
DIY Robocars via Twitter
RT @f1tenth: It is getting dark and rainy on the F1TENTH racetrack in the @LGSVLSimulator. Testing out the new flood lights for the racetra…
Nov 23
DIY Robocars via Twitter
RT @JoeSpeeds: Live Now! Alex of @IndyAChallenge winning @TU_Muenchen team talking about their racing strategy and open source @OpenRobotic…
Nov 20
DIY Robocars via Twitter
RT @DAVGtech: Live NOW! Alexander Wischnewski of Indy Autonomous Challenge winning TUM team talking racing @diyrobocars @Heavy02011 @Ottawa…
Nov 20
DIY Robocars via Twitter
Incredible training performance with Donkeycar https://www.youtube.com/watch?v=9yy7ASttw04
Nov 9
DIY Robocars via Twitter
RT @JoeSpeeds: Sat Nov 6 Virtual DonkeyCar (and other cars, too) Race. So bring any car? @diyrobocars @IndyAChallenge https://t.co/nZQTff5…
Oct 31
DIY Robocars via Twitter
RT @JoeSpeeds: @chr1sa awesomely scary to see in person as our $1M robot almost clipped the walls as it spun at 140mph. But it was also awe…
Oct 29
DIY Robocars via Twitter
RT @chr1sa: Hey, @a1k0n's amazing "localize by the ceiling lights" @diyrobocars made @hackaday! It's consistently been the fastest in our…
Oct 25
DIY Robocars via Twitter
RT @IMS: It’s only fitting that @BostonDynamics Spot is waving the green flag for today’s @IndyAChallenge! Watch LIVE 👉 https://t.co/NtKnO…
Oct 23
DIY Robocars via Twitter
RT @IndyAChallenge: Congratulations to @TU_Muenchen the winners of the historic @IndyAChallenge and $1M. The first autonomous racecar comp…
Oct 23
DIY Robocars via Twitter
RT @JoeSpeeds: 🏎@TU_Muenchen #ROS 2 @EclipseCyclone #DDS #Zenoh 137mph. Saturday 10am EDT @IndyAChallenge @Twitch http://indyautonomouschallenge.com/stream
Oct 23
More…