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3D Robotics

MAV wing differential

From BotJunkie:

"Part of the appeal of flapping wing micro air vehicles is that (unlike helicopters) they offer some resilience against crashing into obstacles. Crashing is still bad, though, and (with some exceptions) significant damage to things that fly generally keeps those things from continuing to be useful. To mitigate this, Harvard University has developed an itty bitty differential to keep a pair of wings (say, on arobot bee or robot fly) generating the same amount of torque, even if one of those wings is damaged. The beauty of the PARITy differential (Passive Aeromechanical Regulation of Imbalanced Torques) is that it’s completely mechanical, and simply due to its design it will (for example) increase the flapping speed of a damaged wing to match the torque output of a paired, undamaged wing. Basically, it’s the same kind of thing that you have controlling the power to the wheels in your car, except about a million times smaller."
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Another Quad

I'm starting to build my own quadcopter. I'm a newbie in UAV world so I'm trying to understand all the concepts behind with this project.

I started from scratch building my own IMU and all the control (I don't have a RC system yet).

Here are my specs for now:

Control Board:
  • Arduino Mega
  • 3 LY530AL gyros
  • 1 ADXL330 accelerometer
  • 1 XBee Pro module
Mechanical parts:
  • 4 AX 2308n 1100kv rotor
  • 4 Flying 20A ESC with BEC
  • 4 8x3.8 SF Regular props (well... I cannot found pusher props here so I will use the Jose Julio's idea to turn some degrees in front and rear rotors)
  • 3000mAh 3S mystery battery
I'm sure I have miscalculated something but for now, if it hover with some stability and control I'll be happy.

Nothing is working for now, but I did some tests with rotors and ESCs (breaking one rotor in the process).

Here are some pics of the frame and mounting:



All the photos are posted on my profile and as soon as I get the other photos with my brother I'll upload than.

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ArmQuad v. 016 outdoor




I am continuing the ArmQuad software development.
I believe that soon I will release for FREE a ACRO software version with current (or improved ) performance that can be seen in these 2 videos.

Un saluto agli Italiani presenti in questa community.



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3D Robotics

The HoverFly folks got in touch to tell me about their new quadcopter control board, the HoverFly Pro, which will be hitting the market in October for $360. It's got twin Parallax Propeller chips (that's also the chip used by AttoPilot), and has the standard quad controller features with the addition of built-in OSD. That seems like a pretty good price for a plug-and-play (closed source) system. It's not a full autopilot, since there's no navigation ability, but the site lists a forthcoming GPS version, so maybe that's coming (or maybe that's just for position hold--the closed source autopilots have serious regulatory restrictions, which normally limits their waypoint abilities, but we'll just have to wait and see in this case.)

From their site:

Feature List:

- Plug-N-Fly - just hookup to your quad and fly. No calibration software and no tweaking needed.

- All boards come fully assembled. The HoverflyPro is precision
manufactured. Sensors are the smallest on the market and the entire
board is assembled by pick-and-place robots.

- Features 2 Parallax Propeller MCUs that provide a total of 16 microprocessors running in parallel for the fastest data collection and
control of your Electronic Speed Controllers (ESCs).

- MCUs operate at 80Mhz for a total of over a GHz of processing power.

- Operates with Brushed or Brushless motors.

- Support for standard PWM Speed Controllers (I2C is not required).

- On-board voltage conversion switches automatically for 5.0V or 6.0V ESCs.

- UltraPWM technology means better stability. The PWM signal is compressed to achieve a faster update rate without using I2C ESCs.

- Scalable Control - Use any size motor or frame. HoverflyPro is capable of running very large motors.

- Not limited to tiny cameras. You pick the motors, battery and frame for the payload you want to carry.

- On-board voltage regulation. Input power range 6V-15V.

- Direct USB programming. No need to connect flight battery for
programming. Use the Windows update client and any mini-USB cable to
connect to the HoverflyPro. Programming clip no longer needed.

- Position holding gyros on all axes.

- FREE software upgrades. Windows update client notifies you of software updates. A simple USB connection provides quick and easy
software updates.

- You choose the configuration. Quad, Hex, or Octo. In Quad configuration you can pick "+" or "X" orientation.

- Altitude hold via barometer / accelerometer

- Auto leveling

- Automatic Pitch,Roll compensation for video and still cameras.

- Built in control for pan/tilt when in altitude hold mode

- Simple to use. Comprehensive instructions to ensure your success.

- Use any receiver and transmitter. HoverflyPro automatically senses and uses any PWM input.

- Basic and Aerobatic mode. Basic uses accelerometer to keep the quad level when the sticks are centered. It limits the maximum bank
angle achievable. Aerobatic allows the user to rely on the gyros only
for stable, but more extreme performance.



Detailed Specifications

- 2.75" x 2.75" (70mm x 70mm)

- Board height - < 0.5" (12.7mm)

- Programming power - USB or flight battery

- Flight battery - Input power range 6V-15V. Power connection is symmetric (no wrong way to connect power).

- 8x Receiver inputs

- 8x ESC outputs

- Camera Pan/Tilt outputs for camera mount stabilization

- 2x Future outputs (3-pin)

- On-Screen Display (OSD) input and output (3-pin).

- Buzzer

- RGB LED

- XYZ Digital Gyroscope

- XYZ Digital Accelerometer

- Pressure/Barometric Sensor

- Expansion Interface (12-pin)

- ESC voltage conversion output module

- Flight Battery voltage level sensor (for OSD and emergency modes)

- Programming switch (2-position). Base program and advanced feature programs required during update.

- Manual Gain adjustment (potentiometer)

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These camera's are $299, full widescreen HD, 2 hours of battery life. They come with a waterproof casing and are very resistant to shock. Combined with a 16Gb SD card, you can shoot about 4 hours of video. My brother works in LA and he just bought a few of these for a documentary he is going on oyster farming. He has some pretty impressive vids of dredging for the oyster bags under water. I think this would be a perfect addition to arduCopter.
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QuadRotor Project

3689369260?profile=original

I have started my quadrotor project.

Im using the mikrokopter frame with some additional center plates and a few modifications.
E-flite motors, with E-flite ESC. An arduino MEGA board. A Vectornav VN-100 which includes magnetometers, accelerometers, gyros, and an onboard kalman filter. Xbee PRO modules. Laptop with Labview.

Right now Im testing and tunning my own PID controller. Here are some pics of my quad and a small clip showing the actual behaviour of the controller, which I have to improve.




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3D Robotics

Arduino 19 Out Now

You can download it here.

Mostly minor changes, although APM folks who use the Serial Monitor will appreciate the increased control there.

  • SPI library.
  • The Ethernet library has been refactored to use the new SPI library. Existing sketches will need: #include <SPI.h> added to the top of their code. Just select SPI from the Sketch > Import Library menu.
  • String class
  • A0, A1, etc. aliases for the analog input pins
  • shiftIn() function
  • Added Arduino Pro 5V and Arduino Fio to the boards menu
  • Added control over automatic scrolling and outgoing line endings in the serial monitor
Full release notes are here.
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3D Robotics

T3-Round 8 Deadline Extended to Monday

Well, I did it again: scheduled the T3 contest to end on a 3-day weekend in the US and forgot about the holiday. This is Labor Day in the US, and most people have Monday off, so I'm extending the deadline by 24 hours to 12:00 midnight PST on Monday.


BTW, we now have two successful entries. Brakar's very creative double-egg drop mechanism is above. They didn't break!


Get out there and drop some eggs! As always, entries in the comments here.


And remember the egg-drop command is now in the stock ArduPilot code. Couldn't be easier...just uncomment this routine in the Events tab and assign a waypoint to your target location:


{

/*

float temp = (float)(current_loc.alt - home.alt) * .01;

egg_dist = sqrt(temp / 4.903) * (float)ground_speed *.01;


if(wp_index == 3){

wp_radius = 10;

if(wp_distance < egg_dist){

servo_out[CH_RUDDER] = PAYLOAD_OPEN;

}

}else{

wp_radius = 20;

servo_out[CH_RUDDER] = PAYLOAD_CLOSED;

}

*/

}

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1 YEAR AGO

was our trip to NASA.



The thing that disappointed us was how banal the aircraft were. Our focus was always making the hopelessly unstable stable through software & here our government was flying tried & true, statically stable gliders, pushers, & R-maxes. It was hardly the crazy stunt that Ares-1 was.



Sadly, we were depressed about the Air Force. Last year seemed to be a dead cat bounce driven by hope, but the most basic thing never happened with the Air Force & now we're winding down again.

We're not completely dead yet, but we conceded flying UAV's on the golf course is never going to be the happy escape that it was. That was really our #1 weapon against the reality of getting old, forsaking love & all the other stuff in the pursuit of feminism. There was but 1 way our hobby could fail & it failed as hard as it could. Thought it would come back for a year but it wasn't possible.

Nothing we did that year in place of flying actually comes across as enjoyable, just because it was a year in which progress came & went.

Indeed, the most trouble we ever got into was trying to forsake love by spending all our time flying UAV's on a golf course.


HELIX ANTENNA CONTINUES



Open drain hack to get the uBlox to work. It needs configuration commands every time it starts.





Ublox strapped in. Haven't seen any difference between this & the patch antenna on the bench.





Rebuilt yet again.



1 day later. PID calibration required for manual attitude control. The human takes it to levels the autopilot never did. This time, we're shooting to make attitude control permanent.



NOW WE HAVE CAMERA #4.



1080p finally got cheap enough to upgrade from the $100 Canon A's we were crashing to a $190 Sanyo, our very 1st 1080p camera.

The fixed lens & electronic image stabilization shouldn't break in a crash like the telescoping lenses & mechanical image stabilization did. Unfortunately this camera has a rolling shutter. Still photos suck. It gives up a lot of the picture fidelity of the $100 cameras in the name of HD video. Video is recorded at 13Mbps which is not enough for water.

The stock battery dies after only 40 minutes. Buy several aftermarket batteries.



Wasted no time in building a battery eliminator, but this circuit ended up heavier than a stock battery.

Continuous shooting mode requires reducing the compression quality, but haven't noticed any difference between compression qualities.

The battery charger blew up immediately due to a stray solder ball. Be sure to open it up if it rattles. Fortunately, managed to salvage it.

Now some ground footage in case you're in the market.












Looks like Dean successfully blocked Hobbyking from selling clones of its connectors. Ended up using those for all our gadgets & now the price is back to income tax levels.

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GPS news -- PRN 25 now active

In an earlier forum discussion I made the comment that GPS Satellite 25 was having some checkout issues. It has now been declared operational. Story below:



"GPS satellite SVN62 (PRN25) was set healthy today (27 August) at 04:10 UTC.

The satellite, the first of 12 Block IIFs, was launched on 28 May 2010 and went through a three-month evaluation and commissioning period.

Despite some concerns about anomalous fluctuations in the phase of the L5 carrier and in the signal from the currently active rubidium clock package that may affect some high accuracy users, the satellite's performance meets the acquisition specifications. These are the specifications set by the GPS Wing that the satellite's manufacturer, Boeing, must meet.

The satellite was handed over to the U.S. Air Force's Second Space Operations Squadron by Boeing and the GPS Wing on Wednesday."

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SMi’s Unmanned Aircraft Systems 2010 will explore a complete overview of UAS in military, commercial and civilian sectors. Attend and enjoy this unique networking opportunity with key industry leaders and decision makers from the field of UAS. Assess the latest national strategies and industry technology and ensure your organization is strategically placed to benefit from the dynamic growth sector in the global aviation industry.


17th to 18th November 2010, Millennium Gloucester Hotel, London, United Kingdom.







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Aileron modification

3689367790?profile=originalFitting ailerons is not exactly new to the EasyStar so here is my rendition.
Using 1" masking tape I laid out a strip across the entire straight part of the wing









3689367902?profile=originalMarked 10cm from edge of surface (the first part that can be seen when assembled not the hidden section).
Marked 40cm from that mark along.
Cut along both marks
Cut along the side of the masking tape.









3689367826?profile=originalMeasured 5mm back from cut edge (depth of wing in cut)
Cut a diagonal section from the wing (to allow aileron movement)









Using masking tape to template the servo and its throw area (about 1cm longer than just the servo).
Used masking tape to make straight line from box section cut out.
Stuck servo template below masking tape line.
Using scapel I cut out the servo hole and a groove along the masking tape line.








The servo has two tabs so with the servo partially in I marked the foam and cut out little sections for the tabs. It goes in really snug now.









.
To hide the wire I cut a 5mm groove along the box section insert.
With the servo extension cable attached I positioned the connector part on the box section insert and pushed to mark it.
I then cut out that area with a scapel
Cut another groove where the wing meets the chassis for the cable to exit (and attach to the chassis







All closed up and pushed together.
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