quadrotor

Started by RVRENJITH, November 27, 2009, 05:20:21 PM

Previous topic - Next topic

0 Members and 1 Guest are viewing this topic.

anwar

What he has is -+150 deg/sec.  Should work fine ! 

Not sure why the question about 50deg/sec....  availability of more ?
Hangar : Please see my introduction.
RC India forum and me : About this forum.

RVRENJITH

i just asked this question in order to get an idea abt gyros output...........i am havng +-150degree/sec gyro.......is it enough for my project.......
what do u feel abt that??

RVRENJITH

Can anybody provide me with some resources that would help me in developing the 'stabilization part' of the programming in a quadrotor??

RotorZone

Now you are going where I don't have any practical experience. The standard way is to use a PID loop for the control system. The problem with this is I'm not aware of any way to come up with the coefficients other than by experimentation. From what ever simulations I have played with, it is not very difficult to get a reasonably stable system just by judicious trial and error tuning. If you are looking for the most theoretically optimal solution, then I'm clueless how to get there. If I were to do it, I would just tune it by flying it. If you have RC control and you can switch on and off the stabilization, you should be able to do it safely. You might also need Kalman filtering for the accelerometer signals. I'm getting outta here before you ask about Kalman....

Probably you could take a look at the paparazzi code (open source). You might be able to adapt the Kalman code from there.

RVRENJITH

#29
I have shortlisted two motors for my quadrotor........there urls are pasted below.......
http://www.hobbyking.com/hobbyking/store/uh_viewItem.asp?idProduct=4700&Product_Name=hacker_Style_Brushless_Outrunner_20-22L
http://www.hobbyking.com/hobbyking/store/uh_viewItem.asp?idProduct=9996&Product_Name=ADH30S_Micro_brushless_outrunner_6100kv

Please suggest if any other good motors are available .........itz very urgent.........

anwar

The two you have listed are vastly different in terms of everything (KV, current, weight, size).  Are you undecided, so you are getting both ?

Remember that selection of motors start with the AUW of the intended aircraft.  Are you basing your selection on this ?
Hangar : Please see my introduction.
RC India forum and me : About this forum.

RVRENJITH

The total weight of the quadrotor will b close to 1800gms.
So which motor should i use??
Do u have any suggestions??

anwar

Hmm... here is where my lack of any sort of direct experience with these things show up  :(

Usually, there are rules of thumb like you have to have around 400watts power for each 1000grams of AUW.  But since this is a quad-rotor, and there are 4 motors sharing the load, my guess is that you should be able to go with less. I am not sure if that is 25% of what is normally required, so if I were you, I would over engineer it a bit.

Hangar : Please see my introduction.
RC India forum and me : About this forum.

antojk

My piece of advice on the microcontroller. Check out

http://arduino.cc

It is a great place to start on an atmel based microcontroller project. There is lot of reference projects and libraries for servo control, i2c, pwm, mems sensor interfacing etc. A development environment and bootloader support coming from an MIT inspired project project. And a great coding metaphor to work on. Also, you have a number of clone designs to work with and a really great open source community.

http://diydrones.com/profiles/blogs/ardupilot-home-page

The above link shows them using the same dev platform for an autopilot for DIY drones. They have deployed advanced logic like Kalman filtering and prediction to get the autopilot working.

The boards for dev are available in India from

http://ashwin.venkat.googlepages.com/arduino

A great advantage, the whole thing is OpenSource tech, including various add on daughterboards etc.

In fact I used the setup to dev a transmitter. I am now planning to use the Maxstream module add on board for radio link

arunreddy

hi RVRENJITH,

FYI : There is loads of material at http://www.rcgroups.com/forums/showthread.php?t=1097355

Hope it will be of some help to you..!!


-Arun Reddy.
---------------------------------------
Trying to build a QUADROTOR.
Motivated by Ashish Bhatt's Quadrotor in 3 Idiots.

dinil

http://arduino.cc

hey now arduino available at cochin

RVRENJITH

please help........

it has been along time since i have been searching for the brushless motors and the ESC in india.
Now since there no time i am planning to order these motors and the ESC from the US.
and i am using a 10*8 propeller.
The motor is http://www.hobbyking.com/hobbycity/store/uh_viewItem.asp?idProduct=5691
The ESC is http://www.hobbyking.com/hobbycity/store/uh_viewItem.asp?idProduct=5691
will these combo do the work.
the total weight of the craft is supposed to be around 1600 gms.


RVRENJITH

Is there any relation between the size of propellers used and and the voltage of the LiPo cell used??
If the propellers used are 10*8 ,then cant be a battery with 11.1V be used??

rcforall

Yes is the simple answer  and  the key to understanding it lies in  the basic fundamental of a DC Motor  which is high school  physics .

Speed and torque  in a DC  Motor  are inversely proportional .

In the case of a BLDC Motor  KV = RPM/V

So now can you understand the relation between prop size and  voltage if the prop is considered to be the load .
Sai
www.zuppa.io : vehicle telematics, ADAS, IoT , Drones

anwar

Quote from: RVRENJITH on March 05, 2010, 02:58:55 PM
Is there any relation between the size of propellers used and and the voltage of the LiPo cell used??
If the propellers used are 10*8 ,then cant be a battery with 11.1V be used??

This has been discussed many times before, but to summarize (again!) :

1.  The motor prop combination is determined by the weight of the model and the type of flying.

2.  You have to choose a prop that is in the list of supported props for the motor (determined by the KV rating of the motor mostly, which in turn translates to the rpm at which the motors turns). 

3.  The load rating of the motor (as measured by the current drawn in amperes) by a given motor/prop combination determines the speed controller to be used, and that in turn determines the battery voltage (lipo cell count).

Now based on this, you will realize that it is not easy to give a "yes or no" type of answer to your question.  Unless we know what motor and ESC are being used. 

You have posted the motor link twice above instead of the ESC link.  And for that motor, the recommended props are 11x4.7, 11x3.8 and 11x5.5.  A 10x8 does not look at it is suitable, if you are asking about that motor. 

Plus the ESC still needs to be clarified, which has a direct impact on lipo selection.

You have to be careful with the prop selection, or the results can burn your pocket !
Hangar : Please see my introduction.
RC India forum and me : About this forum.

RVRENJITH

in a quadrotor four propellers are used out of which two are pusher type and two are tractor type.
what should one do if the two variants of the suggested props for a given motor are not available??


RVRENJITH

i am having so much doubt regarding quadrotor because i have learned about the quadrotor from google and referring to several threads.

Now i am really confused.I have taken a project done by the columbia university guys as my reference and till now i was taking my steps according to that and i have ordered a 10*8 propeller set.I have already spent a lot of money for getting the gyroscopes and accelerometers.
Now after your reply i feel that i made many mistakes.

Can you suggest me the brushless DC motors,ESC,propellers and the battery to be used and also the place from where these stuffz can be brought(from india)

Please help me out its very urgent.

anwar

To be clear, I did not say a 10x8 will never work. It needs to be paired with an appropriate motor and ESC, that's all.  If you are following an earlier setup, please follow it (as close as you can ) for everything.  So see what motor (how many watts and how much KV rating) they were using, and find the closest one for your project.  Similarly for the ESC, see what was the amps rating.

I am not sure at all on what is the thrust distribution in a quad-rotor (no experience at all).  Please see what the Columbia guys did (basically, what was the AUW of their hovercraft, and what wattage motors they used), and that should give you a fair idea of what type of motor you need to get.  Once you know what you need, you should be able to find the equipment locally.

Hangar : Please see my introduction.
RC India forum and me : About this forum.

rcforall

#43
Renjith ,
The number of Quad Projects going around in India are many  that we know of itself  .
The fundamentals for set up selection has to be understood  and not  copied letter to letter word to word .
We have the set up and the 3 blade  props in matched  pairs available for them and many  students including those from IIT's buy these from us  for their projects .
Its the motor that is critical  that has to determine the prop and not the prop determining the motor.

As Anwar says  it is not that the 10 x 8 will not be suitable but since you have  bought the prop you now have to  settle on the motor to spin that prop .

But be aware that you have to have sufficient stock of the props  if you are going that way as the likely hood of breaking  them on testing is high.
Otherwise the better is to keep those you have bought as spares and redesign  a motor, prop , battery combo over again .

The electronics that  goes into it will remain the same irrespective of the power system hence that is not a waste .

So cheer up  nothing to get confused about , relax  and think rather  than get worried  , from what you say it looks that  you are  confused onlly because of the props you have bought  which  actually is the least of the problems.

Sai
www.zuppa.io : vehicle telematics, ADAS, IoT , Drones

denis

you can buy from rotor sports chennai.
buy online from rotor.co.in

vivekr

im from pune n doing quadrotor as my final year project.Im ordering req. components from rotor.co.in chennai. plz somebody tell me how many days it will take for actual delivery after payment?

amir

3-4 as per my experience
Amir Shabeeh Ahmed
www.fbots.in

pankaj

#47
i m trying to build quadrotor almost since 2 years,

to read my full experience just goto

http://pankajwasv.blogspot.com/
and you have come to right place,rcindia has all you need

RVRENJITH

i have made the structure and had a mini lift off.........but its using a remote control....
i need help in programming out the PID controller for the quadrotor......help me out.....


dinil