A few Teething problems with APM 2.5

[benchmark]

I own 2 Nazas and one wookong controller and this is my first APM controller. I think it is fantastic and i am eager to get it working perfectly.

Can anyone help me with some advice, i seem to be having some teeting problems with my APM2.5

First, let me mention that i have the APM 2.5 with uBlox -6H GPS  mounted on the tricopter with 750kv motors, 10x4.7 props and 3 S batteries.

It flew perfect yesterday for my maiden test flight , i have 2 modes, Stabilize, loiter and RTL  (all with Simple mode enabled), everything worked flawlessly yesterday but today it seems to be acting up.


Here are my problems and questions.

1. It flys great in Stabilize apart from the fact that it does not fly in a straight line deviates to the left if i send it forward, likewise it deviates to the right if i pull the pins back, This is not so much of a problem but it would be nice if it flew forward in a straight line.
Attempted solutions: I  thought it was a compass problem so i recalibrate d my compass , but no change. I also disables automatic declination and set my declination manually but it did not help. I can always adjust my trim on the radio but i  would like it to be better without trimming on the radio.

2. If i switch to Loiter or RTL, it starts to drift seriously and attempted to flip. This is strange because it worked fine yesterday ! :eek:
Attempted solutions: i recalibrated my Magnetometer but no change. Yes, i wait for a full GPS lock before i take off.

3. If and when i get Loiterto work again, Can i fly around in constantly after activating loiter mode until i am ready to land? i know the throttle pin now only controls altitude but this will still allow me to hold position if i release the radio pins,  something like flying in GPS mode with the Naza and wookong ....or is this discouraged with the APM?

4. finally, when i am in the field with the laptop and  go into the mission planner, my google map does appear on my location, it works fine at home when i have internet coverage. Does the mission planner need internet service to construct maps in the mission planner?

[firey1]

i can only answer No4
yes you need an internet connection for the maps to update

[Gaza07]

I was going to say about number 4 but the other problems are very strange 

[rickp]

1. It flys great in Stabilize apart from the fact that it does not fly in a straight line deviates to the left if i send it forward, likewise it deviates to the right if i pull the pins back, This is not so much of a problem but it would be nice if it flew forward in a straight line.
Attempted solutions: I  thought it was a compass problem so i recalibrate d my compass , but no change. I also disables automatic declination and set my declination manually but it did not help. I can always adjust my trim on the radio but i  would like it to be better without trimming on the radio.

Maybe your APM is too close to your power distribution board, and its causing interference?

Motor interference compensation in AC 2.9.2

2. If i switch to Loiter or RTL, it starts to drift seriously and attempted to flip. This is strange because it worked fine yesterday ! :eek:
Attempted solutions: i recalibrated my Magnetometer but no change. Yes, i wait for a full GPS lock before i take off.

I';d work up slowly to this. First get alt+hold working well. If you';re on 2.9.1 its worth checking your vibration levels - as it uses the z accelerometer to help it hold altitude. That same technique will be used for x and y in 2.9.2.

3. If and when i get Loiterto work again, Can i fly around in constantly after activating loiter mode until i am ready to land? i know the throttle pin now only controls altitude but this will still allow me to hold position if i release the radio pins,  something like flying in GPS mode with the Naza and wookong ....or is this discouraged with the APM?

Yes, this is the intention - and should be improved in 2.9.2.

4. finally, when i am in the field with the laptop and  go into the mission planner, my google map does appear on my location, it works fine at home when i have internet coverage. Does the mission planner need internet service to construct maps in the mission planner?

If you go to Flight Planner, then right-click and select ';Map Tool'; and ';Prefetch'; - you can collect the mapping tiles for your flight field in advance, at the zoom level you want.

[Gaza07]

Excellent reply Rick the ';Prefetch'; maps thing should be very useful 

Maybe your APM is too close to your power distribution board, and its causing interference?

Motor interference compensation in AC 2.9.2

I';d work up slowly to this. First get alt+hold working well. If you';re on 2.9.1 its worth checking your vibration levels - as it uses the z accelerometer to help it hold altitude. That same technique will be used for x and y in 2.9.2.

Yes, this is the intention - and should be improved in 2.9.2.

If you go to Flight Planner, then right-click and select ';Map Tool'; and ';Prefetch'; - you can collect the mapping tiles for your flight field in advance, at the zoom level you want.

[peter_a]

Have I gone deaf or is the volume very very low !!!!!

I can ( Just ) hear it with headphones on the laptap !!!!

[rickp]

Yeah, Randy had the mic gain too low on that video.

[benchmark]

Thanks for the response guys.
It seems that i was able to reproduce that youtube video on my center and my compass also gets affected by the motors it seems, it get off up to 30 degrees.
I did also try to do the ';compassmot'; command in the Terminal setup but it keeps telling me  ';invalid command, type Help for list of commands';

What do i do now?

Thanks you for the tip about Prefetching the maps. 

[rickp]

';compassmot'; will be in 2.9.2

[benchmark]

I see , i guess i have to wait for the 2.9.2 release, at least there is hope. At the moment my PCB board is on the bottom deck and the APM board is on top of it on the next deck. I may try to lift my whole APM board unto some kind of elevated platform i may construct. Cana sheet of aluminum tape between them also help to reduce the interference?

[peter_a]

What is the size of your craft benchmark ?

Just seeing if bigger arms would be an advantage by moving the motors away from the control board , or is it the esc`s making the interference  ?

[benchmark]

its actually a large foldable tricopter, the motors themselves are 45 cam from the APM board but from what i can read on the internet , its not the motors themselves that is the main problem but the current the motors are drawing from the PCB board on the frame that messes up the magnetometer compass readings.

[rickp]

I see , i guess i have to wait for the 2.9.2 release, at least there is hope. At the moment my PCB board is on the bottom deck and the APM board is on top of it on the next deck. I may try to lift my whole APM board unto some kind of elevated platform i may construct. Cana sheet of aluminum tape between them also help to reduce the interference?

No. You can';t shield magnetism like that! Best introduce as much of a gap as possible.

[kym]

Rickp says something I am now finding interesting.

The accelerometers are/will be used to help maintain position/alt locks.

Am I right in assuming all the FC firmware are relatively straightforward PID codes rather than
use Kalman-style data fusion?

In the latter technique (and perhaps the related "Particle Filter" methods) the information from all instruments is extracted to achieve optimal control. So to maintain an alt lock all of the
accel info, orientation, magnetometer info, gps info, etc are "fused" together to product a coherent mathematical model of what the aircraft is doing, and hence is able (hey -- at least theoretically :) to achieve an optimal alt lock.

When Kalman filters have extracted what they need from the data, all that';s left is white noise. In that sense they are "optimal".

Maybe this is asking an avr8 to do too much; but it would seem some of the firmwares should be doing it thisaways.

If not, public code is available to do it, and it';s quite interesting to get it going and overcome the methods various known limitations and foibles.