HobbyKing.com New Products Flash Sale
Reply
Thread Tools
Old Jan 09, 2012, 04:52 AM
Mmmmmmm!
WiseDuck's Avatar
Kingdom of Sweden, Dalarna County, Sater
Joined Oct 2011
3,353 Posts
Good test. I'm gonna have a look at the props and whatnot later. I haven't actually balanced the motors or the props. People say that Tiger motors are good, so I figured I wouldn't have to balance the motors. People also say that APC props are good, so I didn't balance those either. I'll have a look at both later and see what can be done. The quad is certainly flyable but I'm sure GoPro footage wouldn't look good with all that wobble. I'll record a movie later and post it here.

What exactly is "TRUSTED_ACCZ" anyway? Is it disabled by default?
WiseDuck is offline Find More Posts by WiseDuck
Reply With Quote
Sign up now
to remove ads between posts
Old Jan 09, 2012, 08:24 AM
Mmmmmmm!
WiseDuck's Avatar
Kingdom of Sweden, Dalarna County, Sater
Joined Oct 2011
3,353 Posts
Alrighty, have a random video. Still wobbles a bit, haven't fiddled with the settings or balanced anything. Just figured I'd test it outside for a bit. I also tested the barometer, it looked alright at first but then it started to overcorrect to the point where it would eventually hit the ground. So right now it doesn't work in an emergency at all, it WILL oscillate up and down until the movement is so large it'll crash. I have NO idea how to tune the barometer. Any ideas?

http://www.youtube.com/watch?v=-OqylcjOEDY

My settings:
WiseDuck is offline Find More Posts by WiseDuck
Reply With Quote
Old Jan 09, 2012, 10:26 AM
Registered User
Deutschland, Schleswig-Holstein, Kiel
Joined Jan 2011
431 Posts
Quote:
Originally Posted by Erknie View Post
As I mentioned above, it's not specific to the ADXL345 it also effects most popular accelerometers, BMA020, BMA180 see this thread for a serious discussion http://www.multiwii.com/forum/viewtopic.php?f=8&t=849
the adxl345 is far more sensitive to vibrations than the bma020.


i tested both with my new quad - with absolute same setup. some little vibrations due cf2822 motors.

with adxl345 there is no chance of stable hover, GUI shows in ACC pitch + ACC roll fluctuating between +50 and -50 , somtetimes up to 100.....
the copter "levels" to that wrong measure .....

with bma020 fluctuates between + 10 and -10, hovers stable and levelled.


imho its better to buy a bma020 for 5 euro extra, and get rid of that vibration-dampening this way.


the mentioned gaui propsavers are great, but they are 5 euro each, and dont help in case of cheap vibrating motors, or after the first little crash with slightly bend motor shaft....

the bma doesnt care that much about vibrations.

maybe, if there are too much vibrations, it may drift, but i did nt have that ACC drift issue with my (bma020)-copters.

the adxl345 is a very nice sensor, but its not quite good usable in vibrating environment.

i recommend to change the ACC of crius lite to bma020 breakout, instead of permanently trying to get rid of vibrations.

my copters fly well even without balancing props or motors. why should i use a sensor, which forces me to buy very expensive vibrationless motors + balancing every prop, if i can get a working ACC breakout for 5 euro?
who cares the 2 gram extra weight....
alteskind is offline Find More Posts by alteskind
Reply With Quote
Old Jan 09, 2012, 10:30 AM
Mmmmmmm!
WiseDuck's Avatar
Kingdom of Sweden, Dalarna County, Sater
Joined Oct 2011
3,353 Posts
Where do you get this acc breakout? And how do you connect it to the board? (Which pins, what changes need to be made in the code etc.) Does the SE version of the Crius board use the same ADXL345 accelerometer? I get a lot of wobble, tuning hasn't changed the stability much but maybe I'm doing something wrong. It works well enough for flying, but it would be real nice to be able to take off into a perfectly level and stable hover.
WiseDuck is offline Find More Posts by WiseDuck
Reply With Quote
Old Jan 09, 2012, 10:52 AM
MyFlyDream
erazotropa's Avatar
The Netherlands
Joined Jun 2010
414 Posts
I have read that using the TRUSTED_ACC, will disable the MAG and altititude!

read: http://www.multiwii.com/forum/viewto...=8&t=849#p5027
erazotropa is offline Find More Posts by erazotropa
Reply With Quote
Old Jan 09, 2012, 11:11 AM
Registered User
United Kingdom, England, Redcar
Joined Jan 2006
3,291 Posts
se
ATMEGA328P microcontroller
ITG3205 three-axis digital gyroscope
BMA180 triaxial accelerometer
BMP085 pressure sensor
HMC5883L axis magnetoresistive sensor (electronic compass)

doesnt look like it
scousethief is online now Find More Posts by scousethief
Reply With Quote
Old Jan 09, 2012, 11:32 AM
Registered User
Deutschland, Schleswig-Holstein, Kiel
Joined Jan 2011
431 Posts
Quote:
Originally Posted by erazotropa View Post
I have read that using the TRUSTED_ACC, will disable the MAG and altititude!

read: http://www.multiwii.com/forum/viewto...=8&t=849#p5027
hm, thats not the words there.....


"3) With not TRUSTED_ACCZ you cannot use MAG and Alt. Hold"



does this mean, u have to use trusted ACC if u want to use mag/baro hold? it will depend on....... http://www.multiwii.com/forum/viewto...t=562&start=40
alteskind is offline Find More Posts by alteskind
Last edited by alteskind; Jan 09, 2012 at 01:24 PM.
Reply With Quote
Old Jan 09, 2012, 11:43 AM
Registered User
Deutschland, Schleswig-Holstein, Kiel
Joined Jan 2011
431 Posts
Quote:
Originally Posted by WiseDuck View Post
Where do you get this acc breakout? And how do you connect it to the board? (Which pins, what changes need to be made in the code etc.) Does the SE version of the Crius board use the same ADXL345 accelerometer? I get a lot of wobble, tuning hasn't changed the stability much but maybe I'm doing something wrong. It works well enough for flying, but it would be real nice to be able to take off into a perfectly level and stable hover.
the SE version has bma180,


if your copter flies stable in acro mode , then the wobbles are ACC made.

the breakout can be bought from member "kinderkram", flyduino.net, viacopter.eu and some others. for germans its cheapest to buy from ELV due low shipping price + less resaler charge

the breakout can be put to the free space on the lite board, and connected to the dedicated connectors on the lite board (GND, 5V, SDA,SCL)

in sketch just comment the adxl345, and uncomment the bma020


u ll find connection shematic there
http://www.rcgroups.com/forums/attac...mentid=3668704
alteskind is offline Find More Posts by alteskind
Last edited by alteskind; Jan 09, 2012 at 11:49 AM.
Reply With Quote
Old Jan 09, 2012, 03:30 PM
MyFlyDream
erazotropa's Avatar
The Netherlands
Joined Jun 2010
414 Posts
Quote:
Originally Posted by alteskind View Post
hm, thats not the words there.....


"3) With not TRUSTED_ACCZ you cannot use MAG and Alt. Hold"



does this mean, u have to use trusted ACC if u want to use mag/baro hold? it will depend on....... http://www.multiwii.com/forum/viewto...t=562&start=40

Well if you read it that way
erazotropa is offline Find More Posts by erazotropa
Reply With Quote
Old Jan 09, 2012, 03:53 PM
Registered User
Australia, QLD, Brisbane
Joined Nov 2011
949 Posts
Quote:
Originally Posted by WiseDuck View Post
Where do you get this acc breakout? And how do you connect it to the board? (Which pins, what changes need to be made in the code etc.) Does the SE version of the Crius board use the same ADXL345 accelerometer? I get a lot of wobble, tuning hasn't changed the stability much but maybe I'm doing something wrong. It works well enough for flying, but it would be real nice to be able to take off into a perfectly level and stable hover.

Accelerometers are meant to detect movement, it's their job, vibration is movement.

So let me get this right, instead of balancing your Tiger motors and APC props to get rid of unwanted vibrations, you are going to the effort of changing the accelerometer. Do you realize that the ADXL345 g range can be programmed for less sensitivity than the BMA020? 16g vs 8g Perhaps you should read the data sheets for both.
Erknie is offline Find More Posts by Erknie
Reply With Quote
Old Jan 09, 2012, 03:58 PM
Mmmmmmm!
WiseDuck's Avatar
Kingdom of Sweden, Dalarna County, Sater
Joined Oct 2011
3,353 Posts
I'm not changing it. And how is the sensitivity programmed? (The SE version uses BMA180 accelerometers) I suppose I could try to balance everything tomorrow, but my methods are crude at best and the parts are supposed to be at least above average. Before I balance anything I'm gonna have another look at the settings.
WiseDuck is offline Find More Posts by WiseDuck
Reply With Quote
Old Jan 09, 2012, 04:01 PM
Registered User
Deutschland, Schleswig-Holstein, Kiel
Joined Jan 2011
431 Posts
Quote:
Originally Posted by Erknie View Post
Accelerometers are meant to detect movement, it's their job, vibration is movement.

So let me get this right, instead of balancing your Tiger motors and APC props to get rid of unwanted vibrations, you are going to the effort of changing the accelerometer. Do you realize that the ADXL345 g range can be programmed for less sensitivity than the BMA020? 16g vs 8g Perhaps you should read the data sheets for both.
some motors, as cf2822, are vibrators. there is nothing u can do than change motors to (more expensive) smooth motors.


i am very interested in trying to make the adxl345 less sensitive.
but i dont know how, i didnt find an answer although i searchred...

what has to be changed in sketch? could u give me a hint?
alteskind is offline Find More Posts by alteskind
Reply With Quote
Old Jan 09, 2012, 04:09 PM
Registered User
Australia, QLD, Brisbane
Joined Nov 2011
949 Posts
Quote:
Originally Posted by alteskind View Post
some motors, as cf2822, are vibrators. there is nothing u can do than change motors to (more expensive) smooth motors.


i am very interested in trying to make the adxl345 less sensitive.
but i dont know how, i didnt find an answer although i searchred...

what has to be changed in sketch? could u give me a hint?
There are many ACC parameters you can adjust, please read this thread, it is now the 3rd time I have posted it.

http://www.multiwii.com/forum/viewtopic.php?f=8&t=849
Erknie is offline Find More Posts by Erknie
Last edited by Erknie; Jan 09, 2012 at 08:40 PM.
Reply With Quote
Old Jan 09, 2012, 04:15 PM
Registered User
Austin, TX
Joined Jan 2009
853 Posts
Quote:
Originally Posted by alteskind View Post
hm, thats not the words there.....


"3) With not TRUSTED_ACCZ you cannot use MAG and Alt. Hold"



does this mean, u have to use trusted ACC if u want to use mag/baro hold? it will depend on....... http://www.multiwii.com/forum/viewto...t=562&start=40
per this response http://www.multiwii.com/forum/viewto...start=20#p6694, if you do not have TRUSTED_ACCZ, then the altitude hold loop still works BUT only uses the BARO data and not the Z-VEL data in the loop to hold altitude..(VEL is inner loop and ALT is outer loop....like LEVEL is outer loop while GYROS are the inner loops in stable mode)....so if your ACC-Z data is noisy when the motors run, you have to disable (this is the default in the code) TRUSTED_ACCZ...if its not, you can enable it to help stop vertical movement...then the VEL P&D terms have effect (note that only ALT P & I terms have effect in V1.9)

note that its been observed that the VEL loop has some bugs....several people are working on the code right now....in addition, there seems to be imminent improvements in the stable mode (LEVEL) by some config code changes to the ACC sensor operation to reduce vibration effects which create drift, by increasing the allowable measuring range of the sensors (8G instead of 2G)...you could try some of the development branches to see them if you like to experiment...I'll just wait myself
Atx_Heli is offline Find More Posts by Atx_Heli
Last edited by Atx_Heli; Jan 09, 2012 at 04:21 PM.
Reply With Quote
Old Jan 09, 2012, 04:16 PM
Mmmmmmm!
WiseDuck's Avatar
Kingdom of Sweden, Dalarna County, Sater
Joined Oct 2011
3,353 Posts
Yeahhh... No. I don't know. I see chunks of code there. I'll just paste it somewhere and see what happens I guess. I'm no programmer.
WiseDuck is offline Find More Posts by WiseDuck
Reply With Quote
Reply


Thread Tools

Similar Threads
Category Thread Thread Starter Forum Replies Last Post
New Product Full Foxtech AIO Glasses Review Guizmo12 FPV Equipment 1362 Dec 13, 2014 08:08 PM
Sold Arduino / MultiWii / Megapirates Boards 3rdeyepro Aircraft - Electric - Multirotor (FS/W) 3 Dec 03, 2011 09:43 PM
Wanted MSR 5in1 boards and MCPX 3in boards beachflyer Aircraft - Electric - Helis (FS/W) 3 Nov 22, 2011 10:14 PM
Discussion Foxtech AIO goggles RX? Teamsherman FPV Talk 2 Oct 02, 2011 11:06 AM
Sold 3 x PCB boards for multiwii copter for $28 madushan2008 Aircraft - Electric - Multirotor (FS/W) 1 Sep 06, 2011 07:53 AM