Arduino Forum

Using Arduino => Sensors => Topic started by: jone31 on Sep 30, 2016, 07:52 pm

Title: Question about angulare motion
Post by: jone31 on Sep 30, 2016, 07:52 pm
Hi there, i have a simpile question abpur angulare velocity.

i want to know if a quadcopter fly with angle 15 degrees. the angulare motion change or equal to 0 ??.

logicaly it equal to 0.

but me i have a problem to progrmming my quadcopter.
i want to contol il with angulare rate. but the problem i can't change the orionation of the quadcopter if the stick in the center. i should send negative value to turn it in the right. and positve value for theleft orientation.

i saw video on youtube that when the stick =0, the quadcopter stop turning !!!! ??? i don't understand why.
logicaly it keep his last moove.
let's we say my input = 50°/s and my sensor is 0°/s so the controler = -50/s so this value will sent to the motor for spining. so when the motor in his max spining the angulare rate =0. because there is no motion. so even we send positive 1  12   40  50 the quadcopter will not moove , iyt keep the max orientation. so i should send negative value to spin because the new commande will be -50°/s sensor =0  se the output will be -50 and it will spin the quadcopter to the max left.

me i attache the drone he is not flying. so i want to know if the drone fly with 15 ° is the angulare rate =0 or not

please helpe

Title: Re: Question about angulare motion
Post by: vaj4088 on Sep 30, 2016, 08:29 pm
Maybe there is a language barrier but I did not understand the question.

I read that the quadcopter flies with an angle of 15 degrees, but I saw nothing about what axis this refers to.

I saw references to "the motor", but this is a quadcopter so there should be four motors.

I do not like looking at You Tube videos, but one was referenced without providing a URL.

I can say this:  If the drone flies in a straight line in any fixed orientation, there is no angular rate.

In fact:

orientation not changing <=> zero angular rate

Getting from 0 degrees to 15 degrees will require an angular rate during that time.
Title: Re: Question about angulare motion
Post by: jone31 on Sep 30, 2016, 08:50 pm
Thanks for the replay.i'm sorry that i didn"t give details.

my problem is i don't understand how we can change the oriontation of the quadcopter only using angulare rate.

for me it is not logical. i will tell why.
imagine you have a control loop . 2 inputes, first input is the sensor of an angulare rate and senconde input is the desirede angulare rate. the outputs is a value that send to the motors. ok

so if i my sensor give me 0°/s and me i want to send 130°/s so the outpute is -130 and this value will rich the motors  forwad motor will be more than the backword motors. ok

now imagine the quadcopter is in his full right. in that moment the angulare rate = 0 because there is no motion.


so if i send the value 0°/s my otpute will be 0 so the motor will continu in his full left. logicaly
but looking this video
https://www.youtube.com/watch?v=CHSYgLfhwUo

from the minute 32.23 to 33.42. when he send the 0°/S the quadcopter will not keep hid full left. he will rich the 0°/s !!!!???? but before when he was at full left his angulare rate is 0, so how do you explaine that the quadcopter will not keep his full left when you send him 0°/S

could you explaine me this please



 
Title: Re: Question about angulare motion
Post by: AWOL on Sep 30, 2016, 08:59 pm
Could you maybe try posting in the French section of the forum?
Title: Re: Question about angulare motion
Post by: jone31 on Sep 30, 2016, 09:14 pm
nop
Title: Re: Question about angulare motion
Post by: AWOL on Sep 30, 2016, 09:34 pm
Would you like to explain "nop"?

Could you maybe try Google translate?
Title: Re: Question about angulare motion
Post by: Delta_G on Sep 30, 2016, 11:46 pm
Would you like to explain "nop"?

Could you maybe try Google translate?
I think he means he doesn't want to try in French where he might be able to effectively communicate with someone and solve his problem but would rather keep posting incoherent nonsense here and never get it working.

OP:  is that about right?
Title: Re: Question about angulare motion
Post by: vaj4088 on Oct 01, 2016, 12:07 am
I do not understand this part of the video, but then I do not understand the questions either.
Title: Re: Question about angulare motion
Post by: jremington on Oct 01, 2016, 01:47 am
Quote
I think he means he doesn't want to try in French where he might be able to effectively communicate with someone and solve his problem but would rather keep posting incoherent nonsense here and never get it working.
jone31 has been working on understanding "angular rate" for a few weeks now. At this rate he/she might have a properly functioning quadcopter in perhaps a decade, two decades tops.
Title: Re: Question about angulare motion
Post by: PaulMurrayCbr on Oct 01, 2016, 05:11 am
Is there any way to change the orientation of a quadcopter? Only way I can think of is a tricky aerial manoeuvre where you lift one side, lift a side next to that one, then drop the copter back down to horizontal.
Title: Re: Question about angulare motion
Post by: vaj4088 on Oct 01, 2016, 05:31 am
All 3D objects, including quadcopters, have three orthogonal axes.  Orientation can change by rotating around one or more of these axes.

You could call the axes X, Y and Z, and you could call the orientation changes yaw, pitch, and roll.
Title: Re: Question about angulare motion
Post by: AWOL on Oct 01, 2016, 10:11 am
Is there any way to change the orientation of a quadcopter? Only way I can think of is a tricky aerial manoeuvre where you lift one side, lift a side next to that one, then drop the copter back down to horizontal.
I thought they used gyroscopic precession, biasing the speed of the clockwise and anticlockwise motors.
Title: Re: Question about angulare motion
Post by: MarkT on Oct 01, 2016, 10:23 am
I thought they used gyroscopic precession, biasing the speed of the clockwise and anticlockwise motors.
That's nothing to do with precession, that's just applying a net torque by balancing the torques
from the two sets of props that counter-spin.


Back to the original question - you are asking why a particular quadcopter's control software is
programmed as it is - that is a question for the author of that software, not for the Arduino
forum.
Title: Re: Question about angulare motion
Post by: jone31 on Oct 01, 2016, 12:03 pm
Thanks i solve the problem, ni my pid the I is to high, cheeeears ;)