Posted by Chris Anderson on September 15, 2008 at 9:30pm
Jordi has finished the first pass on the code for the new BlimpDuino boards. It's best to consider this pre-alpha and not fully functional, but if you want to see how we read IR and ultrasonic sensors, read RC channels, drive a servo and twin motors and use PID loops to hold altitude and navigate, you'll find it instructive. It's practically a primer in Arduino robotics.
Of particular note are the PID control loops, which are a big step up from the basic P (proportional only) loops we were using before. There's also some new code to check the battery voltage and shut down if gets too low, protecting the LiPo.
Overall, this code is designed to be efficient and to conserve power. We run the Atmega using its internal 8Mhz clock rather than the 20mhz external crystal we use with ArduPilot, and we keep ultrasonic pings to a minimum.
The main thing we need to add now is my RC-mode code.
The code is here.
Stay tuned for proper beta code in a week after Jordi's been able to test it in the air.
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Posted by Chris Anderson on September 15, 2008 at 9:23pm
I didn't really warm to podcasts until I got an iPhone, which I naturally sync every day (something I never did with the iPod). Now there's always fresh spoken-word content on my phone, and it's exactly the stuff I want rather than than whatever happens to be on the radio. What I want to listen to is smart shows about UAVs and robots, and fortunately, I've found one. It's called Robots, and you can get it free on iTunes or directly from its website.
For UAVs, check out two recent shows: DelFly and Europe's Micro Air Vehicle Competition and A Robot Fly at Harvard.
You can also check out this show on Flying Insects and Robots from their preview podcast series.
They're all interviews with the researchers themselves, so they're substantive, and they're well produced so they're entertaining. The only think I like to see them do is also cover larger UAVs. They're not as amazing as the tiny flapping ones, but they're more practical.
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Hey everybody...what batteries do you use to power your blimps? From searching around here, I see that Li Pol or AAA are two common choices. Chris mentioned something about having capacity for only about 300mAh with such a system. Is this generally agreed upon? What stops anyone from using 4 or more AAA in series. They seem to be pretty light, 7.6 g per energizer lithium, and provide decent mAh (1250 mAh ... yeah right). Other options, specifically rechargeable NiMH, like the rayovac ic3's, are quite alluring as well, although I assume these are heavier, potentially too heavy for the payload.So what am I missing?my setup is an arduino with two micro servos (one servo is constantly sweeping but this could be changed), a pyroelectric sensor (eltec 442-3), ultrasound, and two n20 motors. I would love to get at least ~1 hour of runtime off of a discharge of AAA's. I think Li Pol would better fit my desires however I would rather get the blimp up and running before I make that investment.I really appreciate it,Ari
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Posted by Chris Anderson on September 14, 2008 at 7:25pm
The South African researchers claim this Zagi flying wing can carry 500 grams of medicine or medical supplies to a location that's otherwise hard to reach. "Clinics in remote areas of South Africa can only be reached on unpaved roads that are impassable in rain," the article says. Given that the range of these electrics is just a few miles, this clearly isn't the right platform, but it's a good concept regardless. [From New Scientist]
Video:
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Posted by HugePanic on September 14, 2008 at 1:00pm
I have bad news here.UAV_Eins hast left at about 15:30Uhr. It just disapeard in the windy skys over southern Hamburg.Way too strong winds, and no way to land securely at the village. So i had to steer higher to avoid further damage. It got just out of sight, and was nowere to be found.With no phone number or name on, the chance to get it back is minimal.So RIP UAV_Eins...RIP about 150€ materialRIP about 15h work...The King is dead, long live the King.. --> UAV_ZwoHere are some Pictures of UAV_EinsRegards
Posted by Chris Anderson on September 13, 2008 at 9:30am
This is just a gripe. Throughout the electronics world polarized components are marked with the stripe or other distinctive marking on the positive terminal. That's fine. But why is that on SMD LEDs the dot and/or green stripe is on the negative side (the cathode)? For through-hole versions, LEDs follow the usual convention, with the positive terminal having the long lead. But only in the SMD versions is it reversed. I know this, of course, so I adjust accordingly, but every time I need to remind myself of this I wonder how such standard-setting error could have happened. Does anyone know?
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Posted by Chris Anderson on September 12, 2008 at 2:00pm
After some wasted time with expensive PCB design errors, we've finally got a release candidate of the production version of the BlimpDuino board. It's version V431.
Changes from previous versions include:
--Square, rather than rectangular, so the IR detectors are all on the outside of the board (and thus free of interference) and evenly spaced for optimal sensing.
--Improved power supply, with lower profile and LiPo low-voltage cut-off (to protect the batteries)
--Vectoring servo now output on a digital pin (10) to use timer-based Arduino servo library
--Various layout tweaks to give more room for various connectors and the on/off switch
--Bug fixes
You can buy the boards here.
Here are the Eagle 5 files: schematic, board.
Here are the components you'll need (Digikey part numbers unless otherwise stated):
Posted by Chris Anderson on September 11, 2008 at 11:51pm
The autonomous helicopter team that we wrote about earlier will give an airshow on the Stanford campus this Monday, Sept 15th at 10:30 am. All are invited. Directions:
To Google directions, search for "Oak Rd & Stock Farm Rd, Stanford, CA"
Driving directions: From I-280: Take the Sand Hill Road exit, drive east for two miles, turn right on Stock Farm Road. Drive one block, turn left on Oak Road. Drive 100 yards, stop at grass field on the left.
From Highway 101, take the Embarcadero Road exit in Palo Alto. Drive west on Embarcadero for two miles, turn right on El Camino Real. Drive one mile, then turn left on Sand Hill Road. Drive 1.3 miles, turn left on Stock Farm Road. Drive one block, turn left on Oak Road. Drive 100 yards, stop at grass field on the left.
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Posted by HugePanic on September 11, 2008 at 1:02pm
The plan for step 2 is to install the FMA - CoPilot as well as the Arduino board for rudder control.Yesterday the first flight with the CoPilot alone were sucsessfully done.This was the first time i was flying a aircraft with some stabilisation help. The FMA CoPilot is a veryveryvery impressive piece of hardware. It even saved the airframe from a crash during estimation of the COG.Now i have to explan the pitch issues i have had with the single aileron. As described in Step 1, the aileron results in large pitching moments.Before activating the CoPilot i was convinced to need a secon aileron.But with the CoPilot active, i had to rethink. The plane is so extremly easy to handle. Set a thrust level, and control it with the rudder. The plane flies like a slotcar on it's tracks. Veryvery precise and stable. I was able to start and land without further changes to the setup at the first trials.The pitching moment of the aileron is compensatet by the CoPilot. If it is necessary at the further development of the plane to recover the plane completely manual, i know that i can fly and land the plane securely. It doesn't fly pretty well in manual mode, but I don't care.Introduction of the Arduino board will start next week. I have to buy more parts....
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Posted by HugePanic on September 11, 2008 at 11:00am
Target of Step 1 was to build a RC Plane with "good" handling for the use as a UAV.I chose a Foam/Depron design with KFm1 (Kline-Fogleman) wing and a box type fuselage.Elevator and rudder are flat.Dimensions:Span: 1.25mLengt: about 1mWeight: about 500g (with FMA-Co-Pilot)These wings are a surprisingly well working compromise for a universal "utility" airfoil.The Step is located at 50% chord length. There is one CF spar, and a plywood reinforcement.First flight went well. I had to adjust the motor angles after that, but thats the same at all aircraft i think.One special point is the single aileron.I don't want to fly any aerobatics, so one aileron should be enough, and it is.After the first flight I enlarged the aileron until the wingtip, now there is enough authority for a uav, even at windy days. The only problem is was that the deep chord of the wings in combination with the single aileron design creates very large pitching moments.I have to programm my transmitter to get them away for manual flight.But the plane is easy to fly for me, event with manual compensation of these moments.See "Step 2" for more about this
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Posted by Chris Anderson on September 10, 2008 at 7:48pm
As they say, the last 10% of the development takes 90% of the time. But we're getting close. Here's the latest:
--ArduPilot: we're now on the second beta of the commerical board, which will be manufactured and sold by a commerical partner to be named soon. Fingers crossed, we've finally squashed all the bugs. As soon as the manufactured boards (PCB plus robotic pick-and-place SMD component assembly) come back from our partner in a week or two, we'll optimize the code on the simulator, and then tweak settings in the air on various airframes. I don't think we'll have a formal beta-testing process, since all the changes will be in the open source code, not the hardware, and will be constantly evolving with your help.
ArduPilot will be sold as a board with SMD parts already soldered and basic firmware loaded in both the Atmega and Attiny (for the failsafe). The user will have to solder on a few easy through-hole parts, such as connectors, which will come in the kit. Out of the box, the autopilot will be return-to-launch only, which is to say that when enabled it will simply return the GPS coordinates of its starting position. Adding waypoints will simply be a matter of adding GPS coordinates to the code in the Arduino IDE and downloading it.
Later, we'll have stand-alone waypoint editing and groundstation software, but that may not be done until we release ArduPilot Pro, early next year. Right now I'm expecting ArduPilot to go on sale around the end of October, target price $29. (required GPS and FMA Co-Pilot sold separately)
--BlimpDuino: Tomorrow I'll post the final board and component parts list, and the beta code a few days later. This board has evolved considerably since its orgins, with the addition of vectoring thrusters, an optional RC mode and ports for optional Bluetooth, magnetometer (compass) and other sensors. This one will go through a beta-testing process (positions already filled, sorry!) before commerical release.
The commerical kit will consist of the everything you need to make a programmable autonomous blimp (board, gondola, motors and vectoring thruster assembly, envelope and one ground beacon), which I believe is the first time such a product has been offered. The only thing you'll need to add is helium, a LiPo battery and a RC unit if you want to also enable manual control. Target price: well under $100.
We hope to have BlimpDuino on the market in November.
As always, both ArduPilot and BlimpDuino will remain totally open source, so if you'd rather order the parts from the various suppliers and build it yourself, you're very much encouraged to do so and we'll do our best to help you. The commercial versions are for those who don't feel confident enough with SMD soldering or otherwise want the security of a pre-made board. We don't intend to make money on them (although we'll ensure that our commerical partner can get a margin that makes it worth their while to offer it)
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From the autopilot's easiest, most newbie task: inserting the boot CD:
"On some laptops, you have to enter "knoppix nopcmcia", otherwise it hangs."
In Paparazzi land, that's actually the way they talk. You have been warned.
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Posted by HugePanic on September 5, 2008 at 1:30pm
This is a report of my first scratch build UAV.Great News, i just finish the maiden flight tonight! Everything went well. Aileron controll is litte too less, as expected with just one aileron! ;)I have to move COG and enlage the single aileron before the next few testflights.BASICSStep1: (Still under work)/b>-Build a RC plane with at least 300g of cargo capacity.-The cargo compartment shall be located at the COG, size about 100x100x150mm.-Two smaller cargo bays. Located front and aft of the COG. Sizes are 60x60x120mm each <-- Updated-The plane should be flying stable, with a low wingloading and good flight characteristicsStep2:-FMA Co-Pilot stabalized flight-Arduino-Auto-Pilot controling ot the rudder for simple maneuvers-Autopilot can be switched during flight (remote controlled)Step3:-Installation of the GPS Sensor-Autopilot controls throttle and HeightStep4:-Waypoint navigationStep5:-Autopilot controlled (throw) launches-Autopilot controlled landings.Design GOALI like the KISS prinziple. So everything should be cheap, but good.My ideas:-Use a single Aileron on left wing only-Mount the FMA-Sensor on a movable platform for advanced Aircraft control (see Forum)-Use the standard aproach with a Adruino Board-Materials:-6mm Depron-CF wing spar-2.5mm Balsa for reinforcement-Lots of hotglue, some tape and a minimum amount of epoxyPart List:-Arduino 10000 Board for Autopilot-FMA Co-Pilot-Cheap 150W Outrunner-25A ESC-Graupner 8Ch Syntesizer RX-3s 1000mAh LiPo Battery-Cheapo 10g Servos for about everything (Aileron, Rudder, Elevator, Sensor-Tilt)Read more…3D Robotics
Posted by Chris Anderson on September 5, 2008 at 12:47pm
Autopilots are export controlled by the International Traffic in Arms Regulations (ITAR), which is why it's very difficult for US manufacturers to sell abroad without incredibly complicated guarantees about security procedures put in place by the buyer. That doesn't just apply to autopilot hardware; it also covers autopilot software, groundstation code and other technology in digital form such as schematics. And "export" doesn't just mean physically sending boxes abroad, it also covers "export by electronic means" such as over the Internet.
So why haven't we been arrested? We publish autopilot code, schematics and PCB design files here, and nearly half of our user base is outside the US. The answer is the "public domain exclusion" in ITAR. Because we're open source and release everything to the general public, it's no longer subject to export control.
Here's a good briefing presentation on ITAR rules. Page 19 says the following:
No Export License is required if the information is:
– Published in periodicals, books, print, electronic, or any other media
available for general distribution to any member of the public
– Generally accessible or available to the public through sales at
newsstands/bookstores and available without restriction
– Readily available at libraries open to the public or at university
libraries
– In patents and open patent applications available at any patent office
– Released with unlimited distribution at an open conference, meeting,
seminar, trade show, or other open gathering and generally
accessible to the general public
– Available in any form after approval by the cognizant U.S.
government department or agency
– Available through fundamental research in science and engineering
at accredited institutions of higher learning in the U.S. where the
resulting information is ordinarily published and shared broadly in the
scientific community (see 22 CFR § 120.11(a)(8))
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Posted by Chris Anderson on September 5, 2008 at 12:32pm
If you positively, absolutely have to DIY everything, here's a how-to on building your own electric heli with a CD-ROM motor. It's the first Angelfire site I've seen for about a decade, so be prepared for a jarring '90s flashback on website design ;-) Still, the thing flies and my hat's off to this guy for the guts to scratch-build something so challenging.
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Posted by Rory Paul on September 3, 2008 at 8:30pm
I cam across this information while doing some research today. I thought that this was a very interesting application of small UAS technology. I do not believe that it would be currently viable with the very technical nature of the systems and the skill set required to operate them but still a very interesting concept.http://www.nhls.ac.za/about_news.html
Posted by Howard Gordon on September 3, 2008 at 7:10am
SmallParts.com is a pretty handy website for prototype builders - I stumbled across them when looking for nylon fasteners and found lots of other interesting stuff - gears, belts, cables, springs, bearings, shafts, tools, etc. Prices are reasonable, though freight is a bit expensive - it cost $8 to get $15 worth of parts via UPS, but otherwise, no complaints. In any case, the site is worth a visit.
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Over at RCUniverse, Greg Covey has written a two-part story/tutotial on how he turned a Multiplex Magister foam trainer into a working homage to the Bell/Agusta BA609 Tiltrotor VTOL aircraft.
The tail thruster looks a little funky to me (it doesn't reverse, so the plane always flys a bit tail-heavy with that thruster compensating) but otherwise it's a very impressive first pass at a fucntioning VTOL. It's not clear to me why the tail rotor is needed at all (it isn't in the full-size plane), but perhaps this will be explained in part two of the series, coming soon.
[Thanks to Craig Horner for the link]
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