Need Help on Loiter and Altitude Hold mode setting- APM

[rajatuj]

I need some help to set the loiter and alt hold mode for my APM Quad , I was trying to fly the quad with any of these two flight mode.
The Issue I am facing is when I switch to any of this mode my quad start abnormal behavior and start to climb up very quickly . All though my purpose  to fly my quad in this mode is to get a stable flight so that I can hold the quad on one position and on certain height but unfortunately  the quad crashed up with the ceiling and I lost two arms and propeller  
Can anyone help me with this and let me know how can I achieve the stable flight with these modes .
If there is any other mode available where I can get stable flight then  please  let me know

Thanks in advance

[akhilzid]

First of all, Don't try althold or Loiter Indoors.

and First setup althold before Loiter.

Read this first: http://copter.ardupilot.com/wiki/altholdmode/#controls

and ask here if any doubt or confusions.

[rajatuj]

Thanks Akhil ..

Then which mode should I select if i want an stable flight indoor ??

If I want to try these modes  out  door then what height should i kept my quad ..

[saikat]

This is a classic symptom - if you do not cover you barometer sensor
with some dark coloured sponge/foam etc..

Have you covered your barometer sensor ??

[rajatuj]

No I haven't covered the berometer  or any other part on my quad ..
is this the root cause of the  issue  I am facing

[akhilzid]

while indoors No modes can make stand still without additional modifications (but somebody done with external processing units and additional sensors),
perfect tuned (CG & PID) copters can almost stable in stabilize mode. but always need an eye on them and cant be unattended state.

with Ultrasonic sensor and optical flow sensors can be stabilized in low altitude(near 50 cm), and without that you need to maintain at least 5 meters from ground.

if its cross windy outside then need to maintain more distance.

[rajatuj]

Ok let me order a new frame again and then I'll test these modes outdoor after covering the Barometer and placing the GPS far from the ESC and APM..

[phanivyas]

Fine tune Stabilize mode first and then Alt Hold. Why do you want to fly indoors? Is your APM enclosed in its case? Vibration levels should be in control & correct Thr_Mid value is required for stable Alt Hold performance.

[rajatuj]

How can I fine tune the Stabalize mode please share some reference ..

As such there is no specific reason for flying the quad indoor .. but  mostly I  got time to work on the quad in the night after my working hours .

yes APM is covered with the case ..

what would be the standard vibration level and how can I correct the Thr_mid value please share the reference ...

thanks in advance

[phanivyas]

What is your frame, motors & props? You can fly OK with the default stabilize mode PIDs but slight tuning of Stab Rate P, Rate P & I for Roll & Pitch is required for better performance. Enable IMU logging, fly the quadcopter, download the dataflash logs and plot the Accel X,Y,Z for analyzing vibrations.

http://copter.ardupilot.com/wiki/flying-arducopter/flight-modes/stabilize-mode/
http://copter.ardupilot.com/wiki/introduction/

Read this first, it will be helpful.

[rajatuj]

Thanks for sharing the details let me go through it and get back to you with the updates..

[rajatuj]

I am using S500, porps - 10x4.5 and motor  Emax Motor 980KV

[rajatuj]

Hi all ..

Need help to setup ALT Hold Flight mode with the APM ..

I have gone through the steps shown on the http://copter.ardupilot.com/wiki/altholdmode/

I have setup all the things  but want to know what is  the ideal behavior when I  shift the quad in this mode .

This time I don't want my Quad to crash again

If anybody have tried this mode earlier then please help me out and share the standard behavior of the quad when I shift the quad in this mode .

Thanks in advance.

[phanivyas]

Multirotor will takeoff once you raise throttle stick above than mid position. When your quad reaches comfortable altitude then center the throttle stick. It should hover at mid position. This should be fine tuned with Thr_Mid parameter. For beginners, reduce Pilot_Velz_Max param to 50m/sec and give it a try. Once you fine tune this mode you can increase it later.

[rajatuj]

Thanks Phani

What would be the Thr_Mid value which I should set

[phanivyas]

You have to figure it out with the help of dataflash log. Read the web tutorial completely before attempting a flight.

http://copter.ardupilot.com/wiki/ac_throttlemid/

[rajatuj]

Thanks Again let me check and get back to you

[SideWinder]

Let the mid throttle be default. You can set that after your next flight.
And please enable logging as it really helps to pinpoint issue. "Enable All" option should be set for logging.

Please cover the barometer properly. Some methods have been mentioned @

http://www.rcgroups.com/forums/showpost.php?p=27054388&postcount=1069

I prefer method 3.

.....For beginners, reduce Pilot_Velz_Max param to 50m/sec and give it a try. Once you fine tune this mode you can increase it later.

@ phanivyas... i think you meant 500cm/sec or 5m/sec. 50m/sec is too much even for an intermediate pilot.

[phanivyas]

@sidewinder: thanks for correcting. yes it is 50cm/sec

[rajatuj]

@sideWinder: I  am using covered APM do I need to follow any of this step to cover the barometer ..

http://www.thanksbuyer.com/image/cache/data/sku-26024-3-600x600.jpg

[phanivyas]

Baro is sensitive to wind and light. So covering the baro with dark foam helps even if you use plastic case/cover.

[rajatuj]

Ok let me do it .. thanks