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Gyro based Gimble

Posted by Dave Skala on February 17, 2009 at 11:58pm
Good day everyone. I never post because I'm a busy guy but hey, let's take advantage of everyone's Expertise!!Here's my current project:We have contracts with Forestry related clients. Currently we haul Repeaters and cellular links up to 3000'AGL to supply them with instant radio/cellular communications. Our system is solar powered and stays aloft for about a week at a time.Recently we were asked to set up camera racks on a picovet for it and so the projects begin!We are using standard off the shelf Pan Tilt Zoom dome cameras (Like store security uses) with a 5.8Ghz downlink for video and pan. We control the system using a joystick and DVR / software package..Our issues so far.Leveling is ok with the Picovet system and keeps the rack fairly stable. Software will handle most of the bounce BUT sometimes the balloon does a complete 360! When this happens, we lose our targets. We will rarely go to full zoom (X30) and normally no more than X15 zoom.We are thinking of two options:Make a 360 pivot point with a slip ring system and a heading hold gyro that will rotate the entore camera dome when a gust hits... (or something like that)ORFigure out a way that a program in the controller could rotate the already exhisting pan of the dome to compensate for balloon drift. Maybe a compass lock sensor of some sort? but could it be piggybacked on that 5.8Ghz video signal??Ideas???? Want to help us?? or be a contractor for this project??Let us know.Thanks again,Dave SkalaAerosight.com
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Government charges woman with illegal export of autopilots to China

Posted by James Ross on February 17, 2009 at 4:25pm
If you're about to deal with interested parties overseas, consider this:Maryland woman charged with illegal export of miniature aircraft controls to Chinatext_link.gif
WASHINGTON (AP) — A Maryland woman was charged Friday with exporting miniature controls for small unmanned aircraft to China.The government says the controls are the world's smallest and involve a technology that cannot be shared with China because of national security concerns. The devices can be used to fly small military reconnaissance planes.Yaming Nina Qi Hanson of Silver Spring, Md., is accused of taking the controls to China last August without a required export license. If convicted, she faces a maximum sentence of 20 years in prison and a $1 million fine (emphasis mine -J).Qi Hanson and her husband, Harold Hanson, arranged over e-mail to buy the controls from a Canadian company, MicroPilot of Manitoba, according to the criminal complaint. Company officials told the couple they could ship the controls to the United States but the couple would have to get an export permit to send the controls to another country.
Read the full articleIt doesn't really help anyone here to have the government use this incident as an excuse to crack down on amateur unmanned aerial vehicles. So please don't do anything stupid like this.
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3D Robotics

Status update on ArduPilot production

Posted by Chris Anderson on February 16, 2009 at 10:34am
Here's a Sparkfun engineering report on those last few boards that got out with incorrect fuse settings. Short form: the glitches from a few weeks ago should now all be gone: "A small number of boards that did not have the correct fuse setting got mixed into the batch that are correctly programmed. Currently, production is programming the correct fuses on all new builds. I am getting someone to go through our storefront stock right now to make sure the correct fuse settings are programmed. So, all boards from now on will have the correct fuse setting and boards sent out after 2/5 that do not have the correct fuse setting should be minimal anyway. Sorry for the confusion and we are sending new boards (hopefully with correct fuse settings now) to customers that have issues and do not have AVR programmers."
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T3

X-Plane simulator for Lego NXT AutoPilot

Posted by Sami Finnila on February 16, 2009 at 7:30am

Here's a auto pilot simulator for NXT AutoPilot based on Michal B's ArduSim.All you need is Lego NXT, RobotC and bluetooth-abled computer to run this simulator. You don't need any of the sensors NXT AutoPilot requires to be able to fly. Although you can add servo controller if you like. As before this simulator is based on X-Plane simulator.Here's how it basically works:-LegoSim.exe communicates between X-Plane (thorugh UDP) and NXT (through bluetooth).-NXT receives GGA sentence (1hz) and the planes attitude (10hz) from LegoSim and sends back servo positions and the telemetry it received as a double check.-LegoSim saves the co-ordinates it received to a .kml file which you can then open in google earth.-LegoSim sends the servo positions to X-Plane.Which closes the circle, so to speak...You should note when using this simulator that the real AutoPilot updates it's attitude and servo positions at almost 300 hz so you can't use the same PID values for your stabilization when flying for real.To replicate this simulation you need:- X-Plane (set it up as described in THIS blog post BUT USE 49003 as the port you define in the settings!!)-Now pair your NXT with your computers bluetooth and memorize the COM port it uses to connect.-Download LegoSim_v.0.0.zip-You can run the LegoSim already and set the IP to 127.0.0.1 and the port to 49003. Set the COM port to the one that NXT uses with your computer and the baud rate to maximum.-Next you need to download and compile with RobotC (ver. 1.45 or above) the AutoPilot for your NXT: NXT AutoPilot Simulator v.0.0.zip- Now in X-Plane set your loaction to Innsbruck and your aircraft to Cessna.- Finally: Press start in LegoSim and then start the AutoPilot program in NXT (you may need to start the AutoPilot several times before it runs OK due to some bugs in my code). Now just release your breaks in X-Plane by pressing b and the auto pilot will take off. (After you have started the AutoPilot you can also hit the "Google Earth"-button in LegoSim..Here are some screenshots of the simulation:Waiting for NXT AutoPilot to start:

Take off...

In flight:

And finally here's a snap shot of two different fly paths one in perfect conditions and the other in heavy wind/turbulence:

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Moderator

Wing upgrade for Superstar (SPAD wing)

Posted by Gary Mortimer on February 16, 2009 at 5:46am
Quite by chance I had a Superstar.When DIYdrones first flighted I was amused to see one being used and I think I have seen in somewhere in the East a military one.

That one having an off and landing on a house which made the local papersAnyhow, after many many fun hours teaching three or four people to fly with the Superstar, whilstI was overseas my young aviator decided to use the Superstar as a chuck glider from the top of their climbing frame.This went well for several flights so I am told, the garden being on a slight slope allowed the Superstar to fly all the way to the bottom.It was not perhaps designed for such things.I was slightly miffed bcause I had recently stripped the covering as it was tatty and the aircraft was now a spirited red.Well the wings were, the fuse had only been started.To cut a long story short, more out of boredom but also out of a desire to prove Dean wrong.For it is he that said he had failed to find an aircraft that the Attopilot could not fly.I determined to make a set of wings, with my boys,from some roofing foam that we had. The fuselage we simply nicked some correx signboards and glued them onto the gaps.Later having flown it, I thought that if I got to 5 hours flying time I would put the dimensions out there so that somebody could do a better job!All we did was tape some dowels in it for strength, cutting it first to what looked the right size in proportion to the airframe. Its a polyhedral 5% crank at the centre 15 at the tips. Again that just looked right.The aerofoil was a soldering iron cut steeper at the front shallower at the back.Then everything was taped together with reinforced tape.Just yesterday I measured it for the first time, the tips are 30 cm and main 90 cm each side making a total of 2.4m Cord 30cm. Quite a neat number for something that was just done by eye!To make things look right on the airframe, the weight and drag of wheels was forgotten.Looked like the thing was going to be short coupled so I increased the length of the rudder and elevator to bring things back a bit.For the first flight it was plain that we needed to strengthen the middle a little as the wings virtually tried to clap. But it flew.On the third flight I added my co pilot, because I also wanted to explore rudder elevator only with the co pilot. I forgot to mention no ailerons in this bird.In the three aircraft I have tried with rudder elevator and co pilot I have found that as long as the gain is reduced the co pilot handles it pretty well. This particular wing has quite a dihedral and the aircraft is inherantly stable.Test flying commenced on the 31st of January and 16 days later after 33 flights 5 hours have been achived, it would have been quicker, but the weather has not played ball.Now done properly, perhaps a built up wing or even a better foam one, properly cut, I am certain the performance will improve.A wing upgrade for your Ardupilot equiped Superstar will increase useful load, and time in the air.I'm using a Dualsky 50 equivalent motor, RAM 12 x 6 prop, 40 amp esc and 3S 2100 lipo.I'm sure somebody here will come up with a neater solution, but I know these measurements work for me so they should for you!With a better matched power set up with electric prop lighter wing and no bodged tail I'm sure an hour would be possible.

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Ardupilot Shield

Posted by bGatti on February 15, 2009 at 7:00pm
So here is a first pass at a Shield for the Ardupilot capable of hosting many of the 3v devices available at Sparkfun.Xbee Pro3v GPS - externalVenus GPS module with chip Ant.2 Axis Gyro3 Axis AccelA Plug for the IR Sensor ModuleThe Board needs more work etc,... But I thought it would be invaluable to put something up as a conversation starter.Eagle Files...OS - Credit: ArduPilot base board for pin locations etc ... Thanks Everyone (Help anyone?)
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Continental Flight - Autopilot right / Pilot Wrong?

Posted by bGatti on February 15, 2009 at 6:26pm
http://www.bloomberg.com/apps/news?pid=20601103&sid=aK22vWGF.UNw&refer=usThis report of the Accident suggests that the rudimentary Autopilot (actually a pilot assist function that gently pushes the stick in the right direction during a stall) - may have been working correctly, and the Pilot reacted by pulling the plane into a 30 degree up attitude, what follows a 30 degree attitude on a flaps-down plane at landing speed is obvious enough.So I propose that at some point, computers will be better able to calculate the physics of flight in real time than any human pilot, and much better than the average fear-afflicted human pilot. Already, the more complicated airplanes are flown only by computer, and not by pilot (Space Shuttle on Reentry etc...)Have we not passed that point? And is the continued reliance on Human Operators contributing to Air accidents?
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T3

update: GentleNAV RTL firmware revision & IMU progress

Posted by William Premerlani on February 15, 2009 at 1:46pm
This is an update on two topics.1. A minor revision to GentleNAV RTL firmware.2. Progress to date on an algorithm to combine 3 axes gyro, accelerometer, and GPS information.1. While working on my next project, I discovered a minor error in the GentleNAV RTL firmware that runs on the UAV DevBoard.There are adjustments in the GentleNAV firmware to the pitch and yaw gyro signals to compensate for variation in A/D conversion of the gyro signals due to changes in battery voltage. Unfortunately, in doing the port from my previous board to the new board, I added the correction instead of subtracting. I did not notice the error during testing because I supply my board with regulated 5 volts from my electronic speed control.Anyway, I have revised both the code and the documentation.2. In case you are wondering what my next project is, I am presently working with Paul Bizard on a simple, fast, accurate algorithm for combining gyro, accelerometer, and GPS information into an estimate of the orientation of a plane. We do not have all of the details worked out, but we are making good progress.Today I implemented one of the components of the algorithm. Paul and I refer to it as update and normalization. It is a routine that uses gyro information only to update a matrix of direction cosine factors and maintains the orthogonality conditions. It works quite well, the drift is extremely low, on the order of a degree per minute. I can spin the board 10 revolutions forward and then 10 back, and the orientation estimate returns to the starting point.The bulk of the implementation uses vector and matrix library routines furnished by MicroChip that they tailored to the dsPIC30 hardware. Execution is very fast. Total execution time so far is 200 microseconds every 20 milliseconds using the 16 MHz clock.The next step is to adjust roll and pitch drift with accelerometer information. When I get that done, I will make that firmware available here as a demo.After that we will adjust yaw drift, and make adaptive gyro gain adjustments. We do not have all of the details worked out, but because of the astounding precision of the unadjusted algorithm, I do not think it will be very difficult.Bill Premerlani
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YARB robotic blimp controlled by Google Android G1 phone

Posted by Howard Gordon on February 15, 2009 at 12:00pm

The open source Google Android G1 phone seemed like an obvious platform for wireless robotic control, so we created an Android-based console. After running this first with the ground-based Surveyor SRV-1 robot, we made a few small modifications and used it to control the Surveyor YARB. The tilt sensors in the Android phone work quite nicely for rotor control - we have proportional steering so the amount of tilt controls the amount of power, and live video is displayed on the Android screen from the blimp's onboard Surveyor SRV-1 Blackfin camera, carried via the same radio channel that sends the control signals.The project is hosted on Google Code at code.google.com/p/srv1console/ as well as www.surveyor.com.Here are some first flight videos -
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Ardupilot activating a Canon camera running CHDK

Posted by Nick Sargeant on February 15, 2009 at 6:46am
I'm looking to get the ardupilot to take photo's using my Canon camera that runs CHDK perhaps when it reaches a waypoint.CHDK has a USB remote shutter function described [URL=http://chdk.wikia.com/wiki/USB_Remote_Cable]here[/URL]Im not sure if any of you have experience with this, but I am right in thinking all i would need to do is get the ardupilot set one spare pin to HIGH for say 200ms when it reaches the desired waypoint?Also, on a side note, I would like to buy the Xbee Pro 868 dev kit but I'm having trouble finding a distributor that would get it to Australia for a reasonable price.Would anyone in the US with a reputable record on DiyDrones be willing to forward this to me in Australia? I would cover all delivery expenses of course.Thanks for your help.Nick
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ArduPilot installed in plane, indoor testing and simulations done

Posted by Michal B on February 15, 2009 at 12:30am
It's still freezing cold outside, so I'm playing by PC with more simulations.My first UAV is ready to go, for now I hooked by FTDI cable to PC, and checking if everything is OK, before going out to make a real flight.The plane may look fragile and ugly, well it is, but at present it is my working plane which I'm used to. Also it was cheap, and is very easy to cut holes in it for adding more wires and putting in more electronics. It weights about 400 gr. Once I make this fly and tested, I plan to go higher to a new 1100gr fuselage.My simulation setup is described in this blog.I run the simulation, and watch if real plane turns servos as expected. Only motor signal is disabled for now (don't need too much wind on my table). All looks fine, so now just waiting for springtime...Plane details:

And ready to fly:

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Let the projects begin!!!

Posted by Blair Davis on February 14, 2009 at 8:11pm

And now the Fun Begins

It's time, the planing is complete, the mission has been established, and the electronics platform for the HK1, is on order. I have taken easy route, and decided to order a plane that I will customize for my project, I think that this will be fairly successful and as my first UAV I think that's saying alot! I will take the wing set and install them into a redesigned fuse, that will house the electronics and powerplant. This plane is unique and blends the hobbies, that I love! Robotics, R/C planes and Rockets, just to name and few! And if you think that is a type then you are nistaken! that is correct, this UAV is desiged the be a Quick Response Vehicle, what's the use in working on a electronics Prototype if you don't have a goal for it? This particular plane will be rocket powered on take off allowing it to be dispached to a locatation that we may not be able to get to quickly and then transistion into a slow flight, currently I am working on a time on station of like three - five hours, but to start, lets just work on getting her home! .... Pictures on and schematics to come shortly so stay tuned the build will be awesome!On a side note, anyone out there have any guidance for vision tracking? and help on one of those awesome little camera ball units?

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Main DIYdrones page "Latest Activity" without user avatars?

Posted by Reto on February 13, 2009 at 4:29am
I noticed yesterday, that the user avatar pics in the "Latest Activity" row, were not shown anymore... at least in my browser). I have some icon instead (one of the following icon from xg_icon-333333.png):

xg_icon-333333.png

Was there some change or update to the blog engine?I think Chris can easily fix this aesthetic technical detail. Thanks in advance, Chris.
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Newbie AVR programming... the hard way!

Posted by Reto on February 13, 2009 at 12:46am
Hi allI like exploring things. When a problem occurs, I like finding out what went wrong... and I like correcting mistakes I made!When ArduPilot came in, step 1 was to check if the CKDIV8 fuse setting was correct... It wasn't. CTRL not working.Step 2: set the fuse correctly. For that, I needed an AVR programmer... no programmer in the house (I'm a newbie).Step 3: get an AVR programmer:- option A: buy what was recommanded on this site (easy way)- option B: do one myself (hard way)Step 4 (I chose option B): get information (AVR programming), choose an easy hardware solution (I chose the DAPA parallel cable solution), do it (cutting an end of a DB25 cable, wiring as information found online to an ISP connector)Step 5: get free programmer software from the web which accommodates DAPA AVR cable... found itStep 5: connect the AVR DAPA cable to ArduPilot's ISP pins, load software, try out reading the signature of the ATtiny45 chip... it works!Step 6: take a look at the fuses... seems logic and easy, but there, the newbie mistake happens:I thought "fuse = 1 = set" "fuse = 0 = not set".... MISTAKE, but I did not know at the time!!!Step 7: setting the fuses as recommended on DIYdrones with help of available information understood by a newbie:I turned all fuses = 0.Step 8: checking if CTRL works... nope!Step 9: connecting the ISP again to check the fuses... ATtiny not recognized by the AVR, no signature read!!!Step 10: the newbie is stuck, reads some more online information, finds out that fuses set = 0 are ENABLED (not disabled as previously thought). I find out that the RSTDISBL fuse, once enabled, blocks ISP access to the ATtiny45. I also found out that DWEN enabled can cause problems for ISP. Fortunately, SPIEN was not reprogrammed (not accessible with the programmer software I used).Only solution to get the RSTDISBL fuse set = 1 again is called "High Voltage Programming". But for that, one needs an adapted AVR programmer capable of applying 12V to the RESET pin of the ATtin45. And this probably cannot be done with the chip installed in a 5V circuit.Step 11: the newbie asks for some more help with some simple questions:a) Has someone experienced doing a High Voltage Programming of a uC installed in circuit? What precautions have to be made.b) Is it possible to disconnect the uC from the board to HV program it, and then reinstall it again?c) Would it be easier to buy a new uC, flash it, and setting it on the board?d) Does the ATiny45 need having its EEPROM programmed? Where can I find the necessary EEPROM hex file? Or is the flash hex all it needs?Additional information about my setup:- I ordered an AVRISP STK500, but it could take some time to get in (the item is sold for 80 USD in Switzerland, so I ordered from abroad for 35 USD!- I also ordered an Arduino Duemilanove, breadboard and components... I found someone having done a High Voltage AVR for setting wrong fuses with an Arduino board (another way to learn a lot of things).Well, so far as a newbie, I learned a lot from all this... the hard way. And since I am as I am, I'll probably go on that way.Of course, in the meantime, my Kadet Senior airframe is not getting much further...But in the meantime, if someone is willing to share some experience or help, I'll welcome him.
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Communication keeps getting cheaper

Posted by Jack Crossfire on February 13, 2009 at 12:30am

Module_Transparent_sm.jpg

These are basically 300ft XBee's for $10. They have no UART, only SPI. They don't have the GPIO functions of XBee's. They're the same size as XBee's. The idea is to bring the data processing of a really powerful computer on the ground to ever smaller, cheaper aircraft with these high speed radios.MicrochipHopefully Microchip is following the Sparkfun model of selling prototyped versions of its chips & not running short batches for reference designs.
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I'm still confuzed on the power for the board

Posted by Bill Raymond on February 12, 2009 at 10:04pm
Hey guys I've fried 2 boards already, first one dunno why. The second time was a stupid impatient error of judgment. Anyways, unlike most of you I have a Nitro engine so no ESC. I'm tired of shorting my board so I want to make sure I understand 100% where my power can come from. I got my board in the mail yesterday, but the back is stamped 1-12-09. It looks like the new ones. I'm not a newbie to electronics, I'm just paranoid now. Thanks
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