QuadRotor UAV
Welcome to my custom built QuadRotor UAV web page. Inspiration for this machine came from the original full sized manned craft which were developed back in the 1920s. The US military also developed various unmanned versions in the 1950s. The PA-4 "Sea Bat" (see pic below) is one example.
The
beauty of these flying machines is the fact that mechanically they are
of very simple design. There are no expensive swash plate mechanisms
and not a single aileron, elevator or rudder in site. As a result,
there is also no need for servos. What is gained
in
simple mechanics though, must
be compensated for in electronics hardware and microcontroller
firmware. There
are numerous electronic hardware design methods possible for flight
control, but
the minimal hardware requirement is a set of three piezo
gyroscopes,
at least one microcontroller, four geared brushed or direct drive
brushless motors and a pair each of cw/ccw rotors. Three simultaneous
PID
algorithms
are implemented
in microcontroller firmware for
pitch, roll and yaw control.
PID update frequency is 1Khz, although the video clip below was taken
with the old 50Hz update frequency.
UPDATE - March 2009 !
While working on custom ESC design, I discovered there were people re-programming cheap Chinese
off the shelf Atmel ATMega8 based ESCs, for 400Hz update using TWI interface.
Thanks to Quax from Germany for all his hard work, proving it possible.
So, I figured if 400Hz TWI was possible, then so too should 1Khz SPI.
After writing assembler code for the Dynam brand 25 amp ESCs, I now have 1Khz update via SPI.
Sounds a simple task, but believe me, there's a lot of work involved.
The biggest headache was coming to grips with BEMF detection. The Chinese ESCs use a 9 resistor detection method. These wire directly from the motor phase windings to the Atmel analogue multiplexer/comparator. No filter capacitors used, so no hardware filter delay problems. I wrote a simple 32 bit moving average digital filter for BEMF detection . Fortunately, the digital filter delay period is the same for all motor RPMs, so can be allowed for in the phase switching timing calculations.
Between each BEMF detection point and the next phase switching point, the ESC opens it's SPI port to receive new 16bit update data if available, from the master micro.
The ESC can, therefore, receive data faster than 1Khz, ie. at the phase switching frequency.
This is limited to 1Khz by the master micro, however.
Pics to follow:
UPDATE 2008 !
I'm currently working on a 3 phase brushless motor version with custom built ESCs.
Speed control is updated at 1Khz via SPI.
Unfortunately, commercial ESCs only update at 50Hz, so are unusable in a 1Khz PID system,
hence the custom built requirement.
VERSION #2 Machine
Click on pics for larger images
Custom built control PCB Block diagram Custom built carbon fibre body
In flight #1 In flight #2
Video Download:
Flight1Nov2006.wmv 4.14 Mb Version #2 Machine
Document Download:
Energy-Efficient_Autonomous_Four-Rotor_Flying_Robot_Controlled_at_1_Khz.pdf
Daniel Gurdan, Jan Stumpf, Machael Achtelik, Klaus-Michael Doth, Gerd Hirzinger, Daniela Rus
UPDATE - March 2009 !
While working on custom ESC design, I discovered there were people re-programming cheap Chinese
off the shelf Atmel ATMega8 based ESCs, for 400Hz update using TWI interface.
Thanks to Quax from Germany for all his hard work, proving it possible.
So, I figured if 400Hz TWI was possible, then so too should 1Khz SPI.
After writing assembler code for the Dynam brand 25 amp ESCs, I now have 1Khz update via SPI.
Sounds a simple task, but believe me, there's a lot of work involved.
The biggest headache was coming to grips with BEMF detection. The Chinese ESCs use a 9 resistor detection method. These wire directly from the motor phase windings to the Atmel analogue multiplexer/comparator. No filter capacitors used, so no hardware filter delay problems. I wrote a simple 32 bit moving average digital filter for BEMF detection . Fortunately, the digital filter delay period is the same for all motor RPMs, so can be allowed for in the phase switching timing calculations.
Between each BEMF detection point and the next phase switching point, the ESC opens it's SPI port to receive new 16bit update data if available, from the master micro.
The ESC can, therefore, receive data faster than 1Khz, ie. at the phase switching frequency.
This is limited to 1Khz by the master micro, however.
Pics to follow:
UPDATE 2008 !
I'm currently working on a 3 phase brushless motor version with custom built ESCs.
Speed control is updated at 1Khz via SPI.
Unfortunately, commercial ESCs only update at 50Hz, so are unusable in a 1Khz PID system,
hence the custom built requirement.
VERSION #2 Machine
Click on pics for larger images
Custom built control PCB Block diagram Custom built carbon fibre body
VERSION #1 Machine
Click
on pics for larger images
Custom
built control PCB
Double
sided PCB
#1 Machine
Block
diagram
In flight #1 In flight #2
Video Download:
Flight1Nov2006.wmv 4.14 Mb Version #2 Machine
Document Download:
Energy-Efficient_Autonomous_Four-Rotor_Flying_Robot_Controlled_at_1_Khz.pdf
Daniel Gurdan, Jan Stumpf, Machael Achtelik, Klaus-Michael Doth, Gerd Hirzinger, Daniela Rus
Convertawings Model "A"
Quadrotor 1956
Links
To Other Quadrotor Builders' Web Sites
| NAME |
COUNTRY |
URL |
|
| Bizart Bizart |
Bulgaria Bulgaria |
Homepage Microdrones Ltd |
http://quadrotor.atspace.org/ http://www.microdrones-bulgaria.com/ |
| Crac | France | Homepage | http://www.skymixer.com |
| Danvel | Spain | Homepage | http://www.angelfire.com/electronic2/danvel/ |
| JoseJ JoseJ |
Spain Spain |
MicroHeli4
Forum RotHeli1 Forum |
http://www.rcgroups.com/forums/showthread.php?t=297067 http://www.rcgroups.com/forums/showthread.php?t=394375 |
| Kwaiweng | Malaysia | Homepage | http://www.angelfire.com/electronic2/waiweng/ |
| Spaceclam | USA |
Homepage | Website Down |
| Tve |
USA |
Homepage |
Website Down |
| Zarx | Canada | Homepage | http://www.angelfire.com/alt2/j-c-paul/Draganfly/ |
E-MAIL
Jim Kearns
Christchurch, New Zealand
2005
Jim Kearns
Christchurch, New Zealand
2005