Great list of trends to watch in 2012 from Make Magazine. The full list:
- Drone Journalism
- Wearables
- 3D Printing
- Internet of Things
- Arduino hits 1 million units
- World "Kinect'd"
- Crowdfunding
- Libraries becoming hackerspaces
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These flying thresher designs show up every now and then. They supposedly have some sort of aerodynamic advantages, but it's not clear what they are since they never seem to make it out of the lab. Here's the latest, from the University of Maryland.
From the video description:
Cyclocopter utilizes cycloidal-rotors (cyclorotors), a revolutionary horizontal axis propulsion concept which has many advantages such as higher aerodynamic efficiency and maneuverability. One of the key advantages of the cyclorotor is its thrust vectoring capability, which is utilized in the present study for yaw control. The present vehicle has a twin-cyclorotor and a horizontal tail rotor configuration where each of the rotors is powered using independent motors.
The cyclorotor design was optimized based on the detailed experimental studies conducted by Dr. Moble Benedict, Mr. Tejaswi Jarugumilli and Prof. Inderjit Chopra. A novel attitude control technique is developed using differential RPM control and thrust vectoring of the cyclorotors for rolling and yawing, and horizontal tail rotor for pitch control. For closed-loop attitude stabilization of the vehicle, a proportional-derivative controller was implemented on an onboard 1.5 gram processor-sensor board. Using this control system, the stable autonomous hover of the cyclocopter was successfully demonstrated.
Inspired by avh's Thingverse 3D files for a replacement ArduCopter frame (shown above), the MakerBot blog has offered a challenge:
9000 internet points and bragging rights to the person who can get me an on-board flight video from any kind of ‘copter sporting any number of printed parts.
I'm not sure what the current conversion rate is between internet points and dollars, but this is worth doing for the bragging rights alone.
I’ve been wondering, what would be the easiest way to route telemetry and commands from APM to Internet. Using 3G modem, would provide almost unlimited range (I know there has been some discussions about this in DiyDrones forum. Here in Finland the GSM network is very covering, but due the way the cellular towers are optimized, maximum altitude where the connection works is probably less than 200 m.)
In theory, list of required hardware is not long. One just needs to receive messages from APM and encapsulate them to UDP packets and send via 3G modem and vice versa. Unfortunately handling PPP communications is too large task for simple microcontrollers. I ended up using BeagleBoard for the sake of easy development and since I had one at hand. I realize that BeagleBoard (which essentially is full computer by itself) is an overkill, but it’s not very heavy and fits easily inside Maja’s fuselage. Basically any embedded system, capable of running linux and acting as an usb host would do. Maybe in the future I figure out some additional tasks for BeagleBoard to do.
The setup works quite nice now. Unfortunately I haven't been able to do much flight testing. Weather constantly sucks this winter here in Finland. As you can see I already installed skis, but there's not even snow, even though it's almost new year.
I wrote more detailed post to my blog, with link to sources: http://antibore.wordpress.com/2011/12/28/routing-apm-communications-to-internet/
Yesterday we scanned an area of around 2 million square meters and made an Ortophoto model with DEM 3d output. The flight was 15 min long. As you can see from the 3d model we scanned an area with diverse terrain. What is fascinating here is that the altitude error is less than 0.5m. From these models we can calculate yearly wood volume changes, we do landslide analysis, do research for flooding areas and more unlimited options.
Helicopters, HTML & democracy: be a HACKER-JOURNALIST
Making software in the newsroom is the best job I’ve ever had.
It’s great work, and it’s for a purpose. We’re not here to “save journalism” (whatever that means) — we’re here to save democracy.
Requirements
- A passion for the news
- Serious programming skills
- An understanding of the inner workings of the web
- Attention to detail and love for making things
- A genuine and friendly disposition
On any given day you might implement a responsive web design w/ HTML5 + CSS3, explore a dataset with a reporter looking over your shoulder, or help invent new ways to report the news.
Bonus points for…
- Experience flying quad-rotor helicopters or mapping balloons
- Information / graphic design
- User experience / usability / empathy
Enter shameless link to sUAS News here
Another Christmas/New Year's video. Enjoy!
This one was made using something like puppetry: an "actor" would hold a quadrocopter (props off) and move it. The motion would be reflected by another (flying) quadrocopter -- so you can do fun things like try to express emotions, walk around with some sort of a gait, look at things, etc.
Happy Holidays!
Hi,
we have performed RC range simulations for 2 systems:
35MHz, 2.5m mean antenna height, 1m receiver height (vertical mast on the UAV)
and
2.4GHz, 2m TX antenna height, 0.5m receiver height (short antennas)
in order to simulate it over a vast terrain we know and use.
The range plot was made from 4km2 elevation model made by Pix4D and Pteryx UAV.
Treat it as a kind of reminder of what happens when landing using FPV.
We know the results are valid since they match our experience
and measurements of range at several altitude levels.
We don't name the systems but mentioned RC systems are the best hobby grade you can buy off the shelf without law & power restrictions.
Things look perfect at flight altitude of 5m, but even with slightly undulated area the horror starts during touchdown, you get anything from 300m to 2km range. The area pictured is 2x2km.
Atmosferic wave diffraction is accounted for (negligible impact here).
ftp://ftp.aerialrobotics.eu/2011-05-18%20czyste/czyste1_txrange_2m.kmz
866MHz 100mW modems were tested and have shown similar range as 35MHz range at ground level (but only with huge 35MHz antenna, strictly vertical). The plot really shows where we have 95% modem bandwidth or good RC control, when overall low control latency is required: during the landing.
From IEEE Spectrum, a report on the latest EPFL research on bio-inspired flying robots:
Gliding is a very efficient way for getting from getting from point A to point B. Jumping is a very efficient way of getting into the air at point A, especially if there are a bunch of obstacles between point A and point B that it would be a good idea to be airborne to make it over. Grasshoppers have been doing this for, I dunno, probably like a hundred million years, and roboticists at EPFL are starting to design their robots with the same kind of jumping talents and expandable wings as our orthopteran friends.
The jumping part, and the crawling around on the ground part, is somewhat impaired by the bot's giant wings, which is why getting this whole folding thing figured out would be pretty cool. Here's the locust-inspired folding mechanism in action:
Video of ROFL Tuning Session with spectacular crash when we deliberately detune one of the PID values! No quadcopters harmed (much) in the making of this video. Video of stable flight below.
By the way, the ROFL quadcopter kit is still on sale on my website: http://www.universalair.co.uk/catalog/rofl for special Christmas/New year price!
The video shows our tuning set up, this is the setup we use to test and tune new control schemes for our ROFL kits, and you can see part of our debug console running on a laptop - it's an app that contains logging functionality, displays raw hex values from the quad, and also sends various parameters with plenty of input boxes and sliders. There are no labels on the sliders and the input boxes because the speed at which we develop the code means we repurpose these inputs for different parameters several times a day. End-users of the quadcopter kit will have a much more streamlined interface that can be used to fine-tune their quads.
The ROFL we use for code development is our ROFL-H variant, which uses Hivebrain instead of Forebrain for the control board. Hivebrain is the same ARM Cortex-M3 powered microcontroller board, but with an integrated surface-mounted XBee module with external antenna. The computer has another Hivebrain module connected over USB (that you can see in the foreground), communicating with the debug console over USB-HID, which we find to be a lot more reliable than USB-Serial that you would normally use with XBees, and a lot easier to implement since Hivebrain/Forebrain has a built-in USB-HID stack in ROM.
At the end, as a quick demonstration, we change one PID component to zero just to see what happens. Turns out this is a bad idea and leads to fast growing oscillations!
Here is another video taken in the same session, testing the current codes response to external disturbances, I use my right hand on the cyclic, so when I am using it to push the quadcopter around I only have throttle and yaw command available. The clutter and confines of the garage are a bit limiting, and we need to add finer throttle control. We are moving to some larger testing grounds soon!
As an engineer of rapidly growing experience, one of the hardest lessons I have learnt is how much time testing and tuning can take.
In an ideal engineering world, no testing is required, and no design modifications are needed during the build. The closest we come to this ideal is in the design and manufacture of very high cost structures such as civil turbofan engines and bridges. However, because these structures are so critical we have to use 99% previously proven theory and design methods, which in turn means changes are incremental, it is not economical to make wild guesses and risk significant differences from one version to another.
Micro UAV design is much the opposite, making exciting new designs into uncharted territory can be very rewarding, discovering new operating regions and performance gains, importantly it is also feasible to do this as mistakes are not economically self destructive.
ROFL, shown flying in the video above, is what I'd class as a structural design tangent, it differs from already available UAVs not in concept, as it uses a conventional quadcopter layout, but in structural design.
The vertical plate design makes the construction extremely simple, the frame very cheap, highly modifiable, at no sacrifice to weight or stiffness. Yet it is very much still a quadcopter.
Converging on a successful mechanical design and writing the initial flight code was a small part of the challenge however, the BIGGEST CHALLENGE then became streamlining the code modifications and tuning!
If each time you make major changes to the code, you have to retune, it's easy to see where a lot of your time is going to be spent over a few months!
Here's a good post by Mark Suster, a VC, on "The amazing power of deflationary economics for startups", which I think neatly explains the economic and innovation model behind 3D Robotics and most other open source hardware companies.
It starts by reminding us of the classic disruptive business model from the Innovator's Dilemma:
In the simplest form, new startups have a product that is INFERIOR to that offered by the competition but at a dramatically lower price with the seller opting for a very thin margin on their product.
Initially their only customers are people who can get by on the reduced functionality or perhaps don’t have the money to spend on the expensive product.
Often it turns out that the market is greatly expanded by having a lower price point new entrant. And over time the new entrant attracts enough business that, as depicted in the graph above, the quality of the product slowly increases over time.
The new entrant keeps margins low but suddenly has a lot of profits due to large volumes of business.
How does the incumbent respond? Not by dropping price & quality – they don’t have an advantage there. Instead they spend more money trying to innovate on product quality and call attention to the weaknesses of the new entrants product quality.
Often major customers defect en masse to the new entrant as they realize that the huge price premium is not justified by the product differentials.
It then provides some questions to ask to see if your product/service fits this bill:
- Does your product dramatically reduce costs in an industry with large incumbents and fat margins?
- Can you provide a narrowly focused product to a niche of that market who will be attracted to dramatically lower costs?
In the case of UAVs, both these seem true: most companies in this space price their products like military-industrial products, not consumer electronics. They typically have the margins of defense contractors. Meanwhile, the civilian/amateur market for UAVs is much more price sensitive and has been poorly served to date, both because of the high prices and also the regulatory restrictions on closed-source vendors.
The open source entrants in this space have the opportunity to be classic disruptors: faster, cheaper and, eventually, better. Starting with the original open source autopilot, Paparazzi, they were initially dismissed as being buggy, hard to use and poorly supported. But as more teams entered the fray, the open source autopilots got dramatically better, and prices continued to fall. Meanwhile the volumes rose: the ArduPilot project, for example, has shipped nearly 10,000 autopilot boards across all its varieties: that's more than all but a handful of the biggest aerospace companies.
Sure, there's still a lot of work left to do to make the open source autopilots as robust as a milspec one, but the gap is closing fast and the open source ones sell for $200 while the milspec ones go for 20 times that or more.
At 3D Robotics (the hardware company behind the DIY Drones store) we think about open source hardware as a "90/10" opportunity: 90% of the performance of commercial alternatives at 10% of the price.
Of course, we'd like to do even better over time--we think that the open source innovation model is not just cheaper than closed source, but can be better, too (think Linux, Firefox, Apache, etc). So maybe 110/10 is possible, or even more when you include things that open source projects are good at, such as introducing new feature quickly and creating open platforms for user innovation.
These are still early days, but I think the civilian UAV market will someday be even bigger than the military one. If the Innovator's Dilemma holds true, bet on the little guys moving fast and cheap to eventually dominate.
4 flying robots in top 5, short piece on engineering.tv.
Samarai UAV Inspired by Maple Seed wins - looks like one of Jack's.
Its interesting that they are doing cool things but not quite breaking out commercially
But the other side of the coin is lots of money is being thrown at UAS in Europe and America really is beginning to fall behind.
Maybe ETH will put out their own or an enhanced opensource AP one day
Made a program that spun Marcy 1 in a variety of throttle & cyclic settings, to measure the effect of cyclic on period.
Regardless of battery charge & battery weight, period for every throttle & cyclic had roughly the same curves. Subsequent test runs got amazingly similar results. The only thing affecting period was PWM.
That was subtracting cyclic from throttle to flatten the curve, but it did the opposite. What seems to be happening is cyclic subtracting more throttle than it's adding which causes RPM to go down.
Then the throttle hits minimum on the subtracted side, but keeps adding cyclic on the added side, which causes RPM to go up. Then we're hitting the limit on the active side & the inactive side for all greater cyclic, so RPM is constant.
Adding straight cyclic to straight throttle gave more consistent RPM curves.
Another algorithm which just subtracted exactly as much cyclic as it added, with the maximum determined by total throttle got pretty flat curves.
Even if we can't fly anywhere, the test jig did show some usefulness. The next great task is making a test jig for altitude.
Then, there was this thing from many months ago.
Thought it could be used as a super cheap airfoil in a monocopter. It
would be limited to the smallest power system. The torque would destroy it. The motor would have to be mounted on it. Extra weight would be required on the balance beam.
Finally decided to move the GUI to C++ from Java. Java is what makes money, but was real clunky & slow. Java required a 188MB development kit on every computer we wanted to compile it on.
Here, the C++ rewrite is on the right & the Java version is on the left. The main difference is how Java uses a proportional font while C++ uses a fixed font, which looks much better.
Lowpass vs averaging notes
After 3 years involved in the subject, we now think averaging is a better deal than lowpass filtering. Lowpass filtering is supposed to remove aliasing, but for all the talk of aliasing, let's consider the disadvantages.
The lowpass filter doesn't buy anything else except removing aliases. A simple, 1st order lowpass filter is not going to chop off exactly at the nyquist frequency. It needs to remove way below the nyquist frequency before all the aliases are truly gone. Finally, it takes a lot of fixed point spagetti code if you want it to work fast, without an FPU.
The lowpass filtering we've used has probably not been as good as the averaging we used before. It's probably caused more oscillation by increasing lag time than averaging caused by letting aliases pass through.
Having said that, the damping foam & ballast we use has allowed the lowpass filter to pass 1/8 its bandwidth in the roll & pitch direction, while passing 1/4 its bandwidth in the yaw direction. That's just as good as averaging, so we're not inclined to change it.
145Mhz radio notes
Some ideas for a voltage controlled oscillator came to mind. Basically, fabricate a multivibrator which can get in the 145Mhz range. Feed a counter with it & have a microprocessor PWM the input voltage. That might get close enough to use only a 256khz ADC.
Common transistors only get 2:1 gain at 150Mhz. The counter would need a high voltage swing. Just don't have enough instrumentation to test the thing. Something could certainly be built in the 1Mhz range, just to test software radio.
What you want is the AD9552, a frequency up converter. That can generate exactly 145.8Mhz for $14. Nothing is cheap in this business. Anything providing decent reception is going to be comparable to a $100 scanner.
This operation has little point. The ISS broadcasts a repeating morse code beacon. You'd get it for 30 minutes per orbit. There was more point in the trapezoidian equatorial mount. That produced images.
Just found this in the news:
The Sea Shepherd ship, Steve Irwin, deployed a drone to successfully locate and photograph the Japanese factory ship Nisshin Maru on December 24th.
Would be interesting to get more information about the system they use... (Range endurance etc.)
Especially the recovery on the small helicopter deck could be challenging.
Merry Christmas to all !!
Marc
The dev team is delighted to give a Christmas present to ArduPlane users in the form of a new geo-fencing feature!
Geo-fencing allows you to define a GPS fence around your flying area, plus a minimum and maximum altitude. Within the fence you can fly ArduPlane normally in any mode you like. If you go outside the fenced area then the APM will automatically take over and bring the plane back to a pre-defined return point, ready for you to have another go.
We're hoping that this feature will both help beginners learn to fly, and also allow experts to perfect complex aerobatic stunts while minimising the risk of a crash. It is also ideal for ensuring that local club rules on flight boundaries and maximum altitude are followed.
You can read all about how to setup and use the new feature in the ArduPlane wiki, but I thought it might be fun to tell you about a test I did of geo-fencing yesterday at my local flying field.
It was Christmas eve, and I was at CMAC testing the geo-fencing code. A family had turned up to watch the planes flying, including Wilson, a 5 year old who loves aeroplanes
I thought this would be the perfect opportunity to test geo-fencing as a training tool, so I asked Wilson if he'd like to try flying a plane by himself. As you might imagine, he enthusiastically agreed!
I took up my SkyWalker with the APM2 fitted, and then enabled the geo-fence. At first I put it in a loiter at about 70 meters, and showed Wilson how he could control the loiter using the transmitter sticks. After mastering that we put the plane in FBWA mode, and Wilson flew it himself. He was delighted!
The fencing really made a difference, as he made some mistakes and flew outside the defined area or too low a few times, but each time the APM took over and brought the plane back to the return point, where it loitered ready for him to have another go. We then flicked the trainer switch to give him control again, and he took the plane around more than a dozen circuits. Not bad for the first time flying a plane at that age!
I also did some test flights with my SkyFun yesterday, and I was delighted to find it worked very well with geo-fencing. One of the reasons I added the geo-fencing feature was to help me improve my manual flying skills. I've found that flying with the APM stabiliser enabled means that my flying skills don't improve as much as I'd like, so I really wanted to practice flying more in manual mode, but I also found that in manual I tend to crash far too often. With the geo-fence enabled I can fly in manual with a safety net. That allows me to really improve my flying skills without crashing. It means I don't need to remember to change modes when I get in trouble - the APM is constantly monitoring my position and altitude, and if I am about to crash it takes over and brings the plane back ready for another try. Great fun!
Many thanks to Wilson for test flying the new ArduPlane code and happy Christmas to ArduPlane users everywhere!
Enjoy your toys, spend time with your families and get ready for a rocking New Year!
(Graphics from the always awesome Max Levine, who's the closest team member to Jerusalem!)
My friends Raven was nearly taken out by Santa!
Some people will already be in it, some about to start and I guess for a few its ages.
Either way I hope you have been good and Santa brings what you were after.
Be safe everybody and have a great time with your friends and families.
Have a nice X-mas... :-)
