Blogs

On the APM developer mailing list, the team recently posted their software roadmaps. Everyone is welcome to join the dev list themselves and follow this, but for those who aren't already signed up, I thought I'd post them here. 

As most of you know, the big recent leap has been full ArduCopter support for the 32-bit PX4 autopilot board, which is now complete and we'll talk about more soon. But in the meantime, here's the ArduCopter software near term to-do list, from team lead Randy Mackay (some of these are already in ArduCopter 2.9.2, which is in beta testing and will be released soon)

• inertial navigation for loiter and waypoints
• compensation for motor interference of compass that leads to heading inaccuracy
• limits (aka geofencing) rework to make more reliable and use less memory
• px4 support
• bug fixes and small enhancements including:
  • single channel failsafe detection
  • make smoother throttle transition from manual <-> auto flight modes
  • rssi pin
  • user controlled yaw-behaviour parameter for auto missions
  • auto loiter command fix-up (ignoring altitude provided by user)
  • auto ignoring altitude as requirements for completing a waypoint
  • CH6 doesn't work for tuning when gimbal is enabled
  • waypoints don't output in dataflash like on arduplane meaning you can't see the waypoints in goggle earth
  • fix flip code
  • i2c sonar
  • do_jump is broken
  • fix hil
  • send failsafe message to ground station

Personally I don't plan more than about 1~2 months ahead because priorities change and because team members are mostly free to work on what interest's them so you end up with happy surprises while also having issues that don't get solved for a long time (especially lower priority items).

The Economist on the positive potential of civilian drones (via Business Insider):

WHENEVER a hiker gets lost in Mesa County, a rugged area in western Colorado, Benjamin Miller of the local police force does not bother to join the search on foot.

His department is a trailblazer in the use of unmanned aircraft, and he launches a drone equipped with an infrared camera to search from the skies. No wayward ramblers have been rescued in this way yet, but he hopes to find one soon.

Drones are best known for their role in the Afghan war, where they both monitor and strike at enemy forces. Now the Federal Aviation Administration has been ordered to find a way to integrate them into American airspace by 2015. The attraction of drones for domestic users is their ability to carry sensors, such as cameras and spectrometers, rather than weapons. This suggests they could be useful in commerce and research, as well as policing. Already scores of organisations have received special approval from the FAA to fly drones. Although there is no regularly updated master list in the public domain, organisations that have received permission range from universities in North Dakota and Michigan to the Departments of Agriculture and Energy. A number are police departments, and it is this development that is stirring up concerns about privacy and protests from local residents.

Their fears are centred on the prospect of surveillance. Since drones can be far cheaper to buy than helicopters--tens of thousands of dollars, as against a few million--the worry is that cameras will be sent up into the sky far more frequently. Even if they are not on a deliberate spy mission, they may capture incidental footage that leads to an investigation, such as evidence of marijuana plantations. Still, at least in Mesa County, the drones have been used for search and rescue efforts and photographing crime scenes. "We're not spying on everybody," says Mr Miller. "We haven't done a single surveillance mission."

In any case, it may not be so easy for a police department to perform round-the-clock surveillance. Their drones are much less sophisticated than military types like Predators, which can remain aloft for 40 hours at a height of 25,000 feet or 8,000 metres (although the Department of Homeland Security has purchased ten Reapers, a new version of the Predator, for border patrols.) The FAA specifies that drones used by public-safety agencies must weigh 4.4lb (2 kilograms) or less, which can be increased to 25lb if the operator is judged proficient. And they are governed by strict rules in the air. They cannot fly higher than 400 feet and must remain within the line of sight of the operator.

Some police forces, however, face obstacles. Florida lawmakers have proposed limiting their use in the state. And in Seattle, two drones that were bought in 2010 for police use have never gone into service. After a hullabaloo, the mayor announced that the programme was to be scrapped. It will soon be easier for police forces to have more eyes in the sky, but first they will have to win over a hostile public.

Read more: 

I've got no idea what this short film is supposed to be about, but if you'd like to see more drones with your bikinis (or the other way around), it's just three minutes long.

(Via BoingBoing)

I Have inserted the starting pass at a much needed section on Vibration Control in the ArduCopter Wiki and would very much like feedback for corrections or additions from you all.

This is  the close coupled mount that I use on my little F330 Flamewheel.

To achieve this plus and minus one tenth G vibration dampening.

In any case, please review the Vibration Control Wiki section under Assembly and give me some (constructive) feedback.

Thank You,

Gary McCray

There have been infrared-guided toy helis before, but they've never worked very well. Perhaps this new one from AirHogs, with a cage to protect the prop, will work better.

From Gizmag:

There are plenty of remote-control micro helicopters that are operated via a smartphone app or a dedicated control unit, and even one that’s controlled by the user’s brain, but Air Hogs has come up with yet another approach. The company’s soon-to-be-released AtmoSphere chopper moves in response to the proximity of the user’s hand.

The AtmoSphere has an infrared sensor on the bottom, that is able to detect solid surfaces up to six inches (152 mm) below the helicopter. When an object (such as a hand) is detected, the aircraft stops and hovers in place. If that object comes closer, the AtmoSphere responds by moving up. It can additionally be moved sideways, simply by pushing gently against its sides.

There’s also an autonomous mode, it which it will move about on its own – the cage surrounding its rotor blades should allow it to bump against ceilings and walls without getting damaged.

Recharging is conducted by placing the helicopter in a small charging cradle, that requires six AA batteries – there’s no word on run time.

The AtmoSphere should be available sometime this year, priced at US$24.99.

Another cool plug-and-play EDA tool with circuit template library for EagleCAD - thanks to open XML (aforementioned)

From HackEDA via DangerousPrototypes

From Jason Kottke:

Geoff Manaugh of BLDGBLOG ruminates on optical calibration targets, weird landscape relics scattered across military bases made to check the resolution of cold war era photograph-snapping spy planes. You can find one target on Google Maps here.

"Although I am truly fascinated by what sorts of optical landmarks might yet be developed for field-testing the optical capabilities of drones, as if the world might soon be peppered with opthalmic infrastructure for self-training autonomous machines, it is also quite intriguing to realize that these calibration targets are, in effect, ruins, obsolete sensory hold-overs from an earlier age of film-based cameras and less-powerful lenses. Calibrating nothing, they are now just curious emblems of a previous generation of surveillance technology, robot-readable hieroglyphs whose machines have all moved on."

Ok - so the critical sub systems for keeping balance, headings etc, are probably best served by a RISC type processor like the ARM and ATMega processors. But on top of that, you could put something that allows an easy access to image processing, communication, logging etc.. In the USAV project I use an Android phone (ARM 600 mHz) to handle the more high level stuff - such as navigation, telemetry, Twitter integration etc... Even though this system is remarkable fast when doing just that (a distance + heading calculation takes roughly 2 milliseconds), this system will be affected once starting to do image processing etc...

I just stumbled across this little thing, that surely would be more powerful and extendable.It has an 1.6 GHz atom processor and uses only roughly 4 watts. You can run any operating system on it and connect usb devices.

The size is only 3.50 x 2.36 x 0.63 inches (89 x 60 x 16mm) which would make it fit in many UAV's.

http://www.linuxfordevices.com/c/a/News/Toradex-Xiilun-PC-and-Topaz-SBC/

A few changes in build plans but still on track. Build parts starting to arrive slowly but surely. A few delivery mishaps that have delayed the build and resulted in going with an Xbee pro S1 rather than the 3DR telemtry. To be honest I flip flopped, decided on Xbee, then 3DR and due to a cancelled order being shipped ended up with the Xbee.

While waiting for parts I have been reading the wiki and forums daily. I can not stress how important this is as a process before and during the build. Reading troubleshooting post and watching videos on calibration of RC controller and setting up of mission planner.

Decided to make my own power distribution harness and forgo the distribution board I bought to save weight and  space on the frame and keep it low profile. Fairly tidy soldering job with heat shrink and testing the connection with a volt meter. Trying to keep weight down by shortening cable lengths to keep things tidy.  Lots of soldering this weekend on ESCs as well as resistor and cap for the sonar sensor.

Purchased two black closed cell (water and fireproof) foam blocks (1 prototype - 1 final) to make a custom canopy. Planning on mounting APM, telemetry, sonar, optical flow, airspeed sensor and receiver to the foam. Going to extend the central mount with the space carbon fibre tubing I have to allow the mounting of two large lipos. This should help vibration and endure spacing between sensors that are affected by magnetic and electrical noise from motors and ESCs. Settled on FrSky TX/Rx with Turnigy 9XR and 2x 5200mah 3s lipos.

Next step is mounting all the above to the frame in anticipation of the final parts Arduino Pilot Mega Flight Computer + GPS + Power module. But before I get ahead of myself I need to refine my setup/ calibration plan as well as flight checklist.

Big thanks to Multirotor.co for the T-Motors parts. Look forward to ordering some MN4014-11 330KV motors for my next build - X8 ;)

 Oklahoma Governor Mary Fallin announced a strategic plan for the state's unmanned aerial vehicle industry - A Strategic Plan for the Development of an Unmanned Aerial Systems Enterprise in the State of Oklahoma

From their home page - "USA-OK is a state chapter of the Association for Unmanned Vehicle Systems International (AUVSI). USA-OK members represent Oklahoma industry, academia, and government. The USA-OK was created in February 2009 in order to promote the emerging unmanned systezms industry in Oklahoma. Read More"

I came across this interesting article and video today. This is the first time I have ever heard of 'Fluoride' batteries.    https://www.youtube.com/watch?v=Itd4V72VvTg    http://www.dailytech.com/Researchers+Create+Fluoride+Battery+Look+to+Replace+Lithiumion+Technology/article23093.htm    Obviously, one of the greatest issues facing the future of drones is flight time. 15 minutes just does not cut it.    Battery technology impacts drones, I think, far more than smart phones. This is simply because drones physically propel themselves in the real world, where as a phone just runs code and lights a screen for the most part.    From what I understand, 'fluoride' is superior over lithium as a battery material in that lithium can store one free electron per atom as opposed to flour ides ability to store 3.    I am wondering what is driving battery research.

Bruce from RC Model Reviews has some very interesting points on this topic and he mentions something about him developing something for FPV models to detect full scale aircraft.

If you fly any type of RC model airplane then you ought to be concerned that various politicians around the world are seeking to have "drones" banned. These people aren't talking about the Predator or Reaper drones we see unleashing hellfire missiles at "insurgents", they want to remove your right to fly any RC model with a camera -- or even any model capable of carrying a camera.

We (the RC and especially the FPV community) need to stand up and be heard now, before it's too late.

I'd love to hear from viewers as to how they think the RC community should respond to this threat to the hobby. Is it time to form a global FPV body which can bring the strength of numbers to weigh when challenging this threat?

And please... don't call any FPV model a "drone" -- it's an RC model (whether it has a camera or not).

Take a look at asena21.pl

Valentine Heart with dedication has been crafted on the sky using autonomous UAV.

Well beyond visual range, below frost point, in dense fog. Somehow it worked, over wast swamps near Wrocław, Poland (pronounciation: WrocLove).

The webpage looks like a quick mash-up but it's there. 4x3km, at 300m AGL.

A movie will come a few days later.

Raw flight recording https://vimeo.com/59659590

You are probably familiar with optical flow sensors which provide extremely precise measurement of ground speed (and therefore position) for quadcopters and computer mice.  The PX4FLOW is the most-recent example but there are many others.

How it works

The optical flow sensor provides a 2D measurement of the angular speed of the image that is moving through its field of view, which is perfect for a mouse but by itself not that useful for a free-flying robot. It cannot differentiate between a near thing moving slowly, a far thing moving quickly, or its own camera rotating. Optical flow must be integrated with other kinds of sensor data for it to make sense in 3D space.

For those familiar with trigonometry, the diagram at right provides an intuitively-correct way of understanding how the various sensors are integrated, and how it can be possible to calculate an unknown value from known measurements.

• Point C represents the center of the optical flow sensor’s view.
• Length b is the current altitude above ground level (AGL) as reported by sonar.
• Angle α is the raw optical flow, minus the current pitch rate as reported by the gyro. (Pitching up or down changes the viewpoint of the sensor, adding to the optical flow. We have to subtract this out to get a grounded measurement.)
• Length a is the ground speed of the craft.

So, given altitude from sonar, pitch rate from the IMU, and optical flow, we can calculate ground speed.

While helpful for visualizing the math, the trigonometric method is only actually correct at α = 0. At α = 90°, a and h hit infinity, which is obviously nonsense. To calculate the actual distance traveled, you must calculate the sum of the movement across point C, which, when you do the calculus, ends up being the exact same formula used to calculate the length of the curved section of a circle segment. I've illustrated this with the second diagram at right.

It might seem that adding that curve to the equation has hopelessly complicated things, but in reality it makes the equation simpler, with no trigonometric functions at all. If I take out the obvious unit conversions, it looks like this:

ground speed = (optical flow - pitch rate) × altitude

A problem, and a solution

In the above formula altitude is a known value directly measured by sonar. Sonar works well in quadcopters and other craft which fly in a hover regime, but tends to be much less reliable in planes, where accurate AGL measurement is probably even more important, especially for landing.

Fortunately, ground speed is not an unknown in planes. GPS and airspeed measurements provide highly-accurate ground speed measurements (there are errors but they’re small compared to the higher speed of the craft). With ground speed solved, we can use basic algebra to move the terms around and solve for a different unknown:

altitude = ground speed / (optical flow - pitch rate)

Thus, we have a reliable and accurate measurement of altitude which works at even greater range than sonar.

Work to be done

The new PX4FLOW has its own sonar altimeter and gyros and performs all sensor integration internally. To add ground speed as an input and altitude as an output, one of the following will need to occur:

• Autopilot reports ground speed to the PX4FLOW, which then integrates it with its own sensors and sends back the calculated altitude, or
• PX4FLOW reports raw optical flow rates to autopilot. All other PX4FLOW sensors are turned off. Autopilot integrates optical flow with its own sensor data, providing improved accuracy of altitude, ground speed, position, and winds aloft.

The second option is the winner in my opinion, as it enables drop-in use of less complex optical flow hardware. I really don’t understand why a redundant IMU was placed on the PX4FLOW in the first place.

Please note that I’m not in a position to do this work myself. My own plane does not have any optical flow sensor, and probably won’t for a long time.  I’m OK with hard landings. I’m just offering the math that you’ll need to implement your own.

Caveats

You may find that your optical flow sensor stops sending intelligible data as the ground gets close. This problem is also encountered with sonar, which has a minimum measurable distance due to the sensor deafening itself while generating the same sound that it needs to listen for. Optical flow fails for a different reason. If we solve for a different unknown we can see why:

optical flow = (ground speed / altitude) + pitch rate

As altitude approaches zero, optical flow will approach infinity. I don’t know the limits of the PX4FLOW (and I don’t have one to test) but I assume the limits are lower than you would want. There are several solutions to mix and match:

• Install flaps, land at slower speeds.
• Mount the optical flow board higher, perhaps under a wing instead of the belly.
• Install a wider-angle lens on the optical flow sensor. The PX4FLOW camera has a 16mm focal length. A shorter lens will widen the view and reduce the detected optical flow. Use simple lenses only, not fisheye/GoPro/FPV, as geometric distortion will cause bad results. Do not use any lens which causes vignetting (black corners) as you will then need to digitally reduce the sample area which will defeat the purpose.
• Solve it in software: Before landing, collect terrain data with a fly by, continue to measure altitude as long as possible on approach, and complete the landing the using the other available sensors.

Searching Youtube I found this video.  I wonder how many Arducopters are still in parts?

From Wired:

For a day, a sandy-haired Virginian named Jeremy Novara was the hero of the nascent domestic drone industry.

Novara went to the microphone at a ballroom in a Ritz-Carlton outside Washington, D.C. on Wednesday and did something many in his business want to do: tenaciously challenge the drone regulators at the Federal Aviation Administration to loosen restrictions on unmanned planes over the United States.

....

Full Story:

Domestic-Drone Industry Prepares...

"Researchers at Universidad Carlos III de Madrid (UC3M) have developed a new system which improves the ability of a GPS to determine a vehicle's position as compared to that of conventional GPS devices by up to 90 percent, and which can be installed in any vehicle at a very low cost.

The system, which is based on sensorial fusion, was jointly designed and developed by the Applied Artificial Intelligence Group (GIAA - Grupo de Inteligencia Aplicada Artificial) and the Systems Intelligence Laboratory (LSI - Laboratorio de Sistemas Inteligentes) at UC3M. The prototype incorporates a conventional GPS signal with those of other sensors (accelerometers and gyroscopes) in order to reduce the margin of error in establishing a location."

Seems like magic, when it's not really and already out on Diydrones! Welcome to arducopter 2.9.2 :)

Full article at http://www.gpsdaily.com/reports/A_system_that_improves_the_precision_of_GPS_in_cities_by_90_percent_999.html

I just received a note from Lee Felsenstein that he will be speaking today as detailed below. (note: Pacific time).  For those not familar, Lee was a member of the Homebrew Computer Club and designer of the Osborne I and many other ground-breaking products.

It should be an interesting talk.

Date: 12 Feb 2013 03:16:43 -0800 
From: Lee Felsenstein <lee@fonlyinstitute.com> 
Subject: EE380 talk Wednesday 4:15PM - Makers, Hackers and the Personal computer Revolution  

I will be giving the EE380 colloquium lecture Wednesday (2/13) at 4:15 PM, on the parallels and divergences between the maker movement and the early personal computer industry (when it, too was still a "movement", propelled by passion and not riches).  With about 36 hours to put the slides and the outline together it will be interesting to see the results. They will be streamed live and available for replay later - see http://EE380.Stanford.edu .  For more shameless self-promotion I offer my new website www.leefelsenstein.com . I really must put up a notice of the 380 event there... 

Hi All, This forum has been so helpful so I thought I would give back and contribute...
I was trying to understand how a previous poster on this forum actually did the 6 Position 2 Pole Rotary Switch Mod with LED Feedback. No where is there a write up on the HOW-TO for the LEDs but there is lots of information on the 6 Mode Selection. 

Firstly, these posts below are great and have been very helpful.  I take no credit on the Mode Selection.  I just figured out the LED part is all.  ;)

There is a DIY Post by Max Levine dated March 30,2011 and another on April 1, 2012. This post shows a picture of the LED's but no writeup to be found.
There is a DIY Post by ARHEXA doing the same thing but no information on LED's. (June 2, 2011)
There is a DIY Post by Paul Mather on DIY DRONES showing how to do this minus the LED's. (June 11, 2011)

Well, all that being said, I knew this is a MOD that I had to have and was not giving up on getting it done.

So let me show the Pictures.... and then I will explain some more.

You might be saying to yourself, why is there only 5 LED's? Good question. If you look closely there is only room on the panel in my desired location for 5 LED's.

So I had two choices : 
First, I could have a 6th Mode with no LED feedback/Indicator/Label
or
Second, just make a 5 Pos Switch and 5 Mode Selection with Labels

I decided to do the latter. I have limited space in my T9x as I have done many mods to it thus far. That being said, that was really the only location that made sense to me to put the LED's and I really don't think I will be using any more than 5 Modes at any given time. And yes, I made a custom Face Plate for the Switch (will explain later).

EDIT: And that when you calibrate your radio sticks/switches/pots, it will mess up your mode selects.  The following configuration will always work and never mess up by a calibration of the radio sticks.

Attached is the How-To-Guide

Here is the Wiring Diagram as well.

All the best!

LTMNO

Hi guys, 

I got permission from my customer to share this story.  

The quad is a DJI Phantom, RTF in 10 minutes when you get your box delivered to you. yes no kidding, it's that simple. 

Of course this kind of product brings a lot of new beginner customers (as well as experienced one looking for a small form factor and easy of flying). 

So here is the story of this customer 4-5 flight, in a super wide open area, safe, really safe for experimentation. 

This is the video of the "trigger failsafe to save my $$$" event. 

Why I post this? 

I really think we should go in that direction for the APM failsafe out of the box. Granted we have more options but complexity and flexibility is not a reason to not have a basic default behavior even if not set in mission planner (for these beginners not reading instructions!) 

(below it is the text version of what was going on his mind.)

Enjoy! 

Dany

CanadaDrones

I didn't know what had gone wrong.  I was baffled and confused when it 
all went wrong so suddenly.  It was only while studying the video later 
that I figured it out.

I normally fly in GPS mode.  That's pretty much idiot-proof as long as 
the Phantom has a good satellite-lock.  But I had switched to Atti mode 
to experiment with improving video smoothness.

You can tell from the video it's in Atti mode.  I flew past my wife at 
high speed, then levelled off and swung it around to point back.  If it 
had been in GPS mode, it should have stopped by itself and hovered in 
that spot.  But in Atti mode it kept right on sailing further away, 
still at fairly high speed.

The problem was that it was such a bright sunny day, with bright snow 
and black trees in the background.  As it drifted even further away from 
me I wasn't sure and couldn't see anymore which way it was facing.  So I 
switched to Home-Lock and pulled back on the stick, thinking that should 
bring it straight back to me regardless of which which direction it was 
aimed at the time.  That was the plan anyway.

I didn't realize that Home-Lock doesn't work in Atti-mode.  I'd never 
tried that combination before.

So, when I pulled full back on the stick, the Phantom responded (quite 
properly) by backing up even more quickly away from me.  And that REALLY 
surprised me, because I wasn't expecting that at all.

At that point I should still have been able to figure out what was 
happening and recover.  But I was so stunned by this unexpected 
reaction, I just didn't know what to do.  I looked down at the 
transmitter to confirm it was actually in Home-Lock mode.  But when I 
looked back up I couldn't even see the Phantom anymore.

Last I saw it, it was heading for the trees across the lake.  So my only 
thought was to add throttle to ensure it clears the trees.

It was much too far away from me.  Did it just go out of transmitter 
range?  Maybe.  But fail-safe should have kicked in automatically then. 
 Did it lose satellite-lock?  If that's the case, then I'm really in 
trouble because I can't even see it anymore to control it manually and 
it might already be headed on its way back to China right now.

I was undecided about turning off the transmitter to force a fail-safe 
return to home.  If it has lost satellite-lock, then turning off the 
transmitter will kill any slim chance at all of my regaining control. 
But I didn't know what else to do.

Turns out, as you can see from the video, I had a solid transmitter 
connection the whole time.  I should have simply switched to GPS mode. 
Then Home-Lock would have worked perfectly.

But in panic, I switched off the transmitter, and instantly fail-safe 
kicked in and saved my butt.  But, it had already been flying for ~6 
minutes, and I was worried it was going to run out of battery time 
before I could get it back to the ground.