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EVOLUTION OF MARCY-1

Posted by Jack Crossfire on January 8, 2010 at 10:00am
Still no idea how to protect the propeller without a plastic injection molded shroud. This is 1 area where a $1000 makerbot would come in handy. Just don't have a $130,000,000 government real estate loan to store it on.

Marcy-1 came in just as heavy as Vika 3. The surface mount board, integrated radio, & new name made no difference. She has a lot more wood than Vika 3 but is more balanced.http://www.rcgroups.com/forums/showthread.php?t=1044312Tried spinning up on a table to ensure stability before lifting off. Didn't have enough thrust to break free of the rod & spinning was unbalanced.

On the test stand for Her 1st revolutions.

Now a test stand video for posterity.Finally, a full power liftoff on the golf course led to this.

Then tried this to get more moment of inertia, unsuccessfully.

She's too unstable. They seem to require precise balance like a propeller. The balance requirement means she needs a 2nd PWM to translate horizontally.The Bladestar must not have used imbalance for translation but relied on the fact that its engines blew sideways. Another point for monocopters.Steve Morris did indeed make a spin copter & it required 2 PWM's for horizontal motion.Also, since the Bladestar appeared, all monocopters have switched from photodiodes to single axis magnetometers for position sensing, making the Marcy 1 aircraft board already busted. Magnetometers would be much easier than photodiodes but we figured their update rate was too slow. Not anymore.Instead of computing north, they just sense an arbitrary sine wave on a single axis magnetometer & rely on a hard coded point in the sine wave to determine where North is.So a silly spin copter is a much harder problem than first envisioned. Marcy 1 needs to be a monocopter.MONOCOPTER NOTESMonocopters use a "balance beam" to keep the angle of attack level. There are no photographs of the Lockheed Samurai but the low resolution video shows it probably uses a gyro instead of balance beam to control angle of attack.It also has a winglet to make it more stable.Predictably, the Goog has nothing on sizing a monocopter since there are no monocopter Adsense hits. Nothing to do but cut some wood.

That lasted about 4 hours. At full power she couldn't exit the launch rod. Shortened the launch rod enough for her to fall off & she went straight into the ground, probably due to insufficient RPM.Tried increasing angle of attack, grinding down the launch stand, & suspected imbalance was causing her to hang up on the launch stand.BALSA TERRORISM

Finally made a number of monocopter variations & a symmetric blade design just to see what would happen if we got her as balanced as possible. The monocopter is very hard to balance because of the limited payload room.The symmetric Marcy 1 finally worked. She lifted off the stand & into a stable hover before running out of room & crashing. Here's the video of the tests leading up to & including success.Balance is everything. A monocopter has to be perfectly balanced about the axis of rotation & the point the launch stand attaches to.

Note that Steve Morris also did this many years ago. He seemed to start over when switching from aerodynamics research to autonomous flight. Here's his monocopter.

Meanwhile, more Marcy-1 evolutions reduced her size, returned her to asymmetry & increased her RPM to achieve useful POV illusions someday, though her disk radius is fixed & limited by weight. The asymmetric wing is seen as important for achieving horizontal translation.That's basically a Bladestar for a lot more money & made by a strange country. The extremely fine traces on Marcy 1 are plagued by dirt. Don't be surprised if the radio appears dead after a landing.In addition to balance, a loss of control after exiting the launch stand can be caused by insufficient power. Move the motor farther from the CG to increase power. There is an optimum distance from the CG at which the motor provides maximum power yet the counterweight is not so far away that the wing is symmetric. The Goog has nothing on this.A test without the balance beam showed it is indeed required for a stable angle of attack. The Goog has nothing on the optimum balance beam size.Suspect Marcy-2 will be a large monocopter. A very large monocopter using a foam wing promises the longest hover time of any VTOL & complete control with only 1 PWM signal.SI4421 VS MRF49XA

Meanwhile, conversion from 72Mhz to 900Mhz isn't going so well. The Si4421 is pin compatible with the MRF49XA but seemingly not electrically compatible. Briefly got SPI out of it due to no particular code change & it went away. It's generating SPI but the PIC isn't receiving it.SPEAKING OF MARCY-1Going to try approaching the AIR FORCE HEROINE again so if we suddenly stop flying you'll know it was another DISASTER.
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My Ardupilot Funjet

Posted by Max on January 8, 2010 at 12:00am
Here is the latest vid, code changes are in the video... anyone have any comments?? :PWell a long time has passed since my "ardustar" flew.Been flying more FPV then anything but I pulled my finger out and slapped my ardu in the funjet - been meaning to do it for so long.Anyway it hasnt flown yet but all the gear is installed and ground tests have been completed!So tomorrow morning is the big day...Im using the stock standard 2.4 ardu code but setup for v tail mixing of course.Im assuming its going to be very twitchy... ill have a play with the code at the park but I think 2.5 will be getting installed as soon as its released.Also put a complete FPV system on the funjet along with 180 degree pan, ill tune the autopilot according to what the camera see's on the plane, should be easy to see if any oscillation problems are resolved that way...Anywho here are the pictures I just took :)Hopefully it will still look this nice tomorrow after the tests hehe...

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My Ground station Beta 2 modding

Posted by Mark B on January 7, 2010 at 9:22am
About MeI'm a LabVIEW programmer/user by profession and I'm also a keen hobbyist/maker so I came across DIY Drones on my hunt for my next project. (Possibly a quadrotor heli...)I saw the groundstation program and downloaded the code to have a look. I couldn't resist modifying the code to be more efficient and 'proper' and I tinkered with the UI.Ground station Beta 2, MB mod v1 UI Preview

Just a little preview mind, I'm in the middle of refactoring the code to make it scalable. This is my way of giving back to the open source community. I am interested in any comments about desired features in the ground station code, such as integration with google maps, custom controls that look like airplane controls, etc is possible.Credit is due to automatik for the current version of the ground station code that I based my mod on.
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UAV inspired by maple seed

Posted by jaron on January 7, 2010 at 6:59am
Lockheed Martin has test flown the Samarai prototype UAV monocopter late last year. Its design is inspired by the maple seed and couldn't be more minimalistic.It's got a 760 mm (30") wingspan, is electrically powered and was built by using off-the-shelf components.
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Wi-Fi Quadraopter with two cameras

Posted by Ty on January 5, 2010 at 7:55pm
I don't know if anyone posted about this before (I missed it if they did).It's on display at the CES in Las Vegas.It struck me, because when I first started playing, I wondered why there weren't any 802.11 telemetry/control models discussed on here. Now I find a quadricopter design, that looks incredibly refined.No price yet (Their website mentions a loaner and developer support for $1200 US)Via EngadgetParrot Website

ar.drone-flying.jpg

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3D Robotics

Come to AUVSI meeting this Friday at NASA Ames

Posted by Chris Anderson on January 5, 2010 at 3:30pm
DIY Drones is a sponsor of the AUVSI Silicon Valley one-day meeting at NASA Ames this Friday (Jan 8), focusing on UAV use for fires and other emergency response. We get a free guest pass as a result, which I'll give to the first person who asks for it in the comments below (you must be a US Citizen or permanent resident, due to NASA rules). Here's the description: "The Silicon Valley Chapter, AUVSI will conduct a forum on Friday, January 8, 2010 to review and discuss the results of the recent exercise held at the Naval Postgraduate School. The exercise investigated the effect of unmanned vehicles on emergency response to wild fires and was modeled after Basins and Indian fires in California in 2006. The exercise involved Forest Service fire experts, government emergency management officials, local emergency responders and unmanned systems experts. The forum will also delve into the wider applications for unmanned technologies in public safety. AUVSI intends to continue these exercises in the use of unmanned system technology in public safety, and they will announce the topic for the next exercise at the forum. " You don't have to be a AUVSI member to attend. It's just $15 and you can sign up online here. If you're a US Citizen, you can also show up and pay at the door on the day.
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3D Robotics

DIY Drones now at 7,000 members!

Posted by Chris Anderson on January 5, 2010 at 10:30am

Today we hit another milestone, with 7,000 members. Over the past year, traffic on DIY Drones has grown more than 3x, from an average of 5,000 page views per day a year ago, to 18,000 today, with a current average of 5,000 vistors per day. We are adding 1,000 members every 70 days, or an average of 14 a day, a pace that is speeding up. At this rate, I expect we'll end 2010 with around 15,000 members, which is kind of awesome. Thanks all!
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3D Robotics

Housekeeping note--blog post or forum thread?

Posted by Chris Anderson on January 5, 2010 at 7:35am
Just a reminder to the community members and especially the moderators: blog posts are for information of general interest to the community. Questions and requests for help should be posted in the discussion forum. Moderators: If someone accidentally submits a blog post that should have been in the discussion forum, do not approve it. Instead, copy it and paste it into a PM to author, asking them nicely to repost in the discussion forum. Then delete the post. If we work hard on maintaining this distinction, we will continue to have a high signal to noise ratio in the center column. Many thanks! Chris
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SPI between ArduPilot, ArduIMU, SCP1000

Posted by Dale on January 4, 2010 at 9:30pm
Finaallly tonight got this to work more completely. SCP baro sensor to IMU was not so hard. Getting IMU and Pilot to work was more trouble for me.The layout I chose is: ArduIMU is spi master, SCP1000 and ArduPilot are slaves.ArduIMU requests airspeed from the ArduPilot, it will be used in combination with the gps based speed in the IMU. It will send the resulting AHRS data to the ArduPilot, as a predefined message, with variables in a certain order. The IMU requests baro from the SCP1000, it will be used in the IMU for altitude, better than the gps altitude. The IMU has the gps connected to it, it will send the req'd lat/lon, etc to the Ardupilot also over spi.As a slave on spi bus, ArduPilot uses the SPI interrupt to trigger shifting each new byte of data in & out of the spi data register SPDR. like this: http://www.rocketnumbernine.com/2009/07/03/using-spi-on-an-avr-3/Even though it's a slave, The SCP1000 uses an extra input to the IMU to tell it when it is ready with a new pressure reading, then the IMU proceeds with asking for it over spi. It could be done other ways, but in higher resolution mode, the SCP only samples about every .5 second. So this way the data is collected precisely when it's available.Pins on ArduPilot:this won't really work with current boards so well, for normal planes. I require only one servo channel. The spi slave requires use of d10, as SS, normally used for servo 2 output. Soldered to a via to access it and get it to a header with the d11, d12, d13.Pins on ArduIMU v1:needed two additional pins, output SS to the Ardupilot, and an input for data ready from the SCP1000. soldered to d8 and d9 (pins 12,13) on the atmega, and brought to a female header. the normal spi pins are nicely available already.Level converter:The SCP1000 is a 3.3v device, don't fry it with 5v lines. made a level converter with a dozen or so discrete components. like this: http://delphys.net/d.holmes/hardware/levelshift.html I even tortured myself with tiny surface mount transistors, oh so fun!Code:If anyone desires a similar scheme maybe this is a starting point. And maybe people will have suggestions for me. I'm sure there are things to improve. With the 1280 based ArduPilot, pins should not be an issue, and this should be faster communication between the micros than UART. But the code may be more complicated, and harder for people to get into.What it does so far is get the airspeed data from ArduPilot back to IMU, in response to a particular message number. And read the pressure sensor. Next will add one larger message from the IMU, with all the data that Pilot would like to have. Should be not too hard, framework is there for messages, just define them appropriately on both ends. There are added .pde files, spi.pde and scp1000.pde that have the relevant code, and some variables and declarations on the main .pde file. should be able to just take the spi and scp1000 files to add in to other code.ardu_100104.tar.gzThis is based on not the latest IMU & AP code, I need to work with that next too. Oh, the IMU code also is modified for 406 gps.Hope this is helpful, please let me know if any questions / comments. Thanks!
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3D Robotics

Modular board strategy for ArduPilot Mega

Posted by Chris Anderson on January 4, 2010 at 5:38pm

In a previous post, I discussed our mainboard approach for ArduPilot Mega. In this post, I'd like to share our thinking about the expansion boards ("shields", in Arduino-speak). As you can see in the above diagram, the core ArduPilot Mega will consist of two layers, just like the current ArduPilot. The core autopilot board will remain constant, while the IMU board will come out in versions, improving as sensor technology evolves. But there is also the option to add a third layer, which is an expansion board for additional functionality. We will break out as many I/O (analog and digital) pins as possible to the expansion board, along with at least two serial ports. Some of the boards, such as the DIY sensor board, will be dual voltage. Some of the boards proposed above may be ones for which there would be enough demand that we'd make and sell them ourselves. Others may be created by the community. ArduPilot is an open standard, like the rest of Arduino, so we'd like to encourage people to come up with their own shields, just as the community has done with the core Arduino boards. So what do you think? Have we missed any obvious expansion board candidates? Any design decisions we should be making with the core ArduPilot Mega board or IMU to allow for more expansion options? (Remember, size is at a premium, so suggestions that require bigger or more expensive mainboards tend not to carry the day)
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3D Robotics

Help AUVSI lobby the FAA for better UAV regs

Posted by Chris Anderson on January 4, 2010 at 3:40pm
From my email today: "Happy New Year AUVSI Members! One of AUVSI's primary goals set by our membership has been to work with Congress and the FAA to move forward implementation of UAS into the National Air Space. While this is an ongoing challenge for our industry, we are making headway. We have scheduled a meeting with the leadership of the Unmanned Aircraft Office of the FAA this week and value your input. I am inviting you, as a member of AUVSI, to have your say on these important matters. If you would like to contribute to the conversation, please email me any topics/questions that you would like us to address with the FAA no later than COB this Wednesday, 6 January, 2010. We are planning to conduct a productive discussion on the challenges our industry faces, so please email me your professional comments and input for consideration at west@auvsi.org. I look forward to hearing from you. Thank you, Gretchen" Please feel to offer suggestions whether you're a AUVSI member or not. (But if you're not, consider joining. It's cheap--$50 for a one year individual membership--and you get the Unmanned Systems magazine each month as part of your membership)
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