How to Crash your Drone in 30 Seconds……. Or Hopefully not with a Little Information

How to Crash your Drone in 30 Seconds…….Or Hopefully not with a Little Information

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So if you’ve got a RC plane, Helicopter or Multirotor for Christmas congratulations, I’m sure you’re going to really enjoy it. I’m hopefully going to explain the opposite of the article title and give you some pointers so you don’t crash your new drone. It should also make your flying more enjoyable and less stressful.

Now for starters like anything most things there are a couple of rules that you need to understand. Generally drones are governed by the countries airspace authority, such as the CAA in the UK and the FAA in the USA. Policy, advisories and rules exist to separate RC aircraft from manned aircraft, keeping them apart and avoiding collisions. Globally airspace authorities are struggling to keep pace with the massive explosion of the hobbyist and commercial drone market. However the general rules are:

FAA know

  1. Fly no higher than 400 feet. Why? Manned aircraft do not fly below 400’, small drones no higher than 400’, therefore they avoid collisions. Never ever fly above 400’ AGL (above ground level) your risking people’s lives.
  2. Always keep your aircraft in sight, you need to be able to determine where is pointing, which direction it’s traveling and be able to recover it and fly it safely back to you. If you cannot see you don’t have correct situational awareness and you likely to crash or have a flyaway (more later.)
  3. Never fly within 5 miles of an airport or on the approach paths to an airport. Again it’s pretty commonsense, but worth mentioning.
  4. If you see a manned aircraft nearby, avoid any chance of flying nearby and if possible land.
  5. Do not fly over or near people. Well the reason is pretty obvious, loose control and you can really hurt someone, if your batteries run out of power, you’ve got a 2lb flying brick falling from 400’, yes it could really hurt.
  6. Don’t fly over Stadiums, this is generally restricted airspace during sporting or events. Again you don’ want your drone falling on people.
  7. Join a club and take a lesson.
  8. Inspect your drone for loose parts, good wiring connections, and tight propellers. Now is the time to find out your wing is loose, not 300’ up in the air.
  9. Do fly for fun, not commercially unless you have a commercial license.
  10. Normally weight restrictions apply, in the USA don’t fly a RC aircraft over 55lbs (unless waivered.)
  11. Don’t fly recklessly or dangerously. If you fly dangerously you can be arrested for reckless endangerment.
  12. Respect privacy. Drone privacy regulations are been formulated and discussed, but normal privacy laws apply. Doesn’t matter if it’s a drone, camera, telescopic, spying on your neighbors is illegal.

For the USA here is a short FAA video on small UAV policies. http://www.faa.gov/tv/?mediaId=997

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OK so that is a quick discussion on the present policy, advisories and regulations, but let’s give you some hard learned lessons and pointers to help you fly safe. So how can you fly safer? Here are some pointers:

  1. When you get your drone, read the instructions cover to cover. Follow the instructions. This is where problems first start. You need to know what each knob, switch, lever on the transmitter does. You need to know the calibration procedures, most drones after been turned on need to be left untouched to calibrate the electronics, plus get things like compass and GPS calibrated. Imagine taking off with your compass wrong and GPS thinking you’re in Cape Town, South Africa, when you’re actually in Huddersfield, England? Well when you take off it’s going to start flying to South Africa! That’s called a “Flyaway”, where the drone just fly’s away out of your control (again flyways mentioned soon.)
  1. Join your local flying club, in the USA your local AMA @modelaircraft club. The people here enjoy RC flying and have lots of knowledge, people who can help train you and hold events like flying contests, fun fly days, BBQ’s etc. Contact your AMA club and attend.
  1. Buy a flight simulator, it really will save you money in the long term. Flight simulators from Real Flight http://www.realflight.com/ . Are very realistic in graphics and flight dynamics. You can learn to difficult maneuvers without crashing, and if you do you just hit RESET and you’re flying again. This really will save you lots of money and climbing trees. Flight simulators are particular important for RC planes where you need to learn takeoff and landings, this is where most crashes occur for beginners. It also teaches you about orientation. Normally a RC plane, copter follows the direction of your transmitter sticks when viewed from behind, however when the plane or copter is pointing towards you the transmitter stick movements are reversed! This is another reason for beginner crash, you’re up in the air and no idea front from back, and you’ve taken off in your back yard and stuffed it into that 40’ conifer tree. Trust me, get a flight simulator fly in manual mode, and avoid all those fancy stabilization modes for now. Fly until its subconscious. Once you have done that, go fly at your RC Club field with seasoned pilots. You’re still going to crash but no way near as if you hadn’t practiced on a simulator. Also the best way to improve is to avoid crashing on the simulator. Fly as if the aircraft was real. You’ll learn a lot faster, practice each simulator session with a set maneuver to improve in mind i.e. take-off, landing, level turns, loops, rolls etc.

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  1. Fly in a big open space, not your back yard unless it’s big! Flying in a small area with limited beginner skills probably means you’re going to crash, your reaction skills and muscle memory haven’t had the correct training yet. You need to subconsciously react, normally if you have to think about which direction you’re pointed, or what to do, you’ve already crashed.
  1. Fly two mistakes high. It’s an old saying but very true. You’ll come to learn what you safety margin is, but your should be able to make two mistakes and recover before you crash. This is more applicable to planes, as nowadays Multirotor have stability recovery systems which recover if you let go of the sticks. Planes if you let go of the sticks they just crash (unless they have the new recovery systems now entering the market.)
  1. Never fly over your head or behind you. It’s the best way to loose orientation and crash. It’s also a safety issue, as any spectators should be stood behind you.
  1. Never fly into the sun. There is a reason WW2 fighter pilots dove out of the sun on their prey, you cannot see and will lose sight of your aircraft and probably crash.
  1. Always check your transmitter and aircraft batteries are fully charged before taking off. There is nothing like the fear of hearing the beeper as your transmitter batteries run out of power and you try desperately to land your aircraft before you lose connection and it flies off in to the sunset.
  1. Avoid Flayaways or recover from them. This can be caused by a number of issues such as firmware updates of your drone, bad GPS and compass calibration, incorrect switch settings etc. Main thing be very careful after doing a firmware update on your drone, and make sure you have completed the correct compass and GPS calibrations. Also be careful when flying with GPS when Solar Flare activity is high, this can disrupt GPS and cause flyaways. If your drone starts to fly where you don’t expect it do the following:
    1. Check your switch settings and move to correct positions.
    2. If that is OK, switch to MANUAL.
    3. If that doesn’t work, switch to RTL or LAND.
    4. If that doesn’t work turn off your Transmitter and the failsafe’s should kick in.
    5. Follow the Instructions for your drone about Flyaway recovery.

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  1. For RC planes practice dead-stick landings, where you throttle the engine all the way back and land by gliding. It’s a good technique to learn for WHEN your motor quits in the future, either from a lack of gas or a low battery.
  1. For Collective pitch helicopters practice autorotation’s, where you cut the throttle and use the blades energy to keep you flying with a flare at the bottom for landing.
  1. Don’t try engine off landing on fixed pitch Multirotor, you’ll just dig a hole in the ground as it falls like a brick.
  1. Follow a checklist every time you fly, manned aircraft do it, it gets you into a routine of checks that no matter how obvious will help you spot issues before they become crashes.
  1. Always aim to land with >20% battery or fuel left. All you need is somebody to crash on your landing area and you’ll be glad you had that spare fuel. Plus it helps your batteries.
  1. Use small smooth control inputs, imagine you’re holding two glasses of water filled to the top. Don’t spill the water, make smooth small movements. Big fast movements over-control your aircraft and before you know it it’s in a death spiral or rocking violently from side to side. Smooth is king. If you’re out of control, center your controls, let the aircraft recover and then take control again.
  1. For RC planes always take-off into the wind and land into the wind, you get more lift and slower takeoff and approach speeds.
  1. For all aircraft monitor the wind and be prepared for gusts. If it’s too windy land.
  1. Practice crosswind landings on the simulator, A LOT, then try them at the flying field.
  1. Practice the basics before trying more complicated flight modes. The basics will save your aircraft when everything else goes wrong.
  1. Have fun, but be safe.

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FPV Racer Photograph courtesy of Hovership

Merry Christmas

Iain

@theUAVguy

https://twitter.com/theUAVguy

http://www.kextrel.com

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eXom – the drone that lets you focus on your work, not on flying

eXom – the drone that lets you focus on your work, not on flying
senseFly brings next-generation rotary UAVs to life at Intergeo 2014

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Sensefly who is well known for its eBee Ag and eBee RTK fixed wing drones, but they have now moved into the Multirotor arena. Announced at Intergeo, Berlin, today the Sensefly Exom was launched to the public. The development has taken over two years, and Sensefly has added some new unique features to the quadcopters functionality which give the Exom unprecedented situational awareness.

 

In addition to seeing what its TripleView camera head sees, eXom’s five vision sensors also enable you to see in the direction the drone is moving – like the visual parking displays in modern high-end cars – for enhanced awareness and safe operation. These sensors work in harmony with eXom’s five ultrasonic sensors to ensure you always know the drone’s distance from nearby objects. Plus, eXom includes the extra security of automated proximity warnings, and shock-absorbent carbon fibre shrouding protects eXom’s rotors in case of surface contact.

 

In another first for a civil drone system, the eXom’s autopilot-controlled TripleView head allows you to view and record any type of imagery required – HD video, ultra-high-resolution stills, thermal data, or all of the above. All without needing to land in order to swap cameras. Since its head faces the front, eXom can fly up close to target structures for sub-millimetre data resolution. The head’s 270° vertical field of view also means eXom can document objects directly above it; crucial for challenging tasks such as inspecting underside of a bridge.

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eXom’s unparalleled level of sensory intelligence means it is easily controlled, even in the most demanding situations (e.g. approaching a high target positioned hundreds of metres away), without the need for a remote control or piloting skills. Simply choose your flight mode:

Interactive ScreenFly mode – click or tap the on-screen video feed to define an object of interest. eXom’s intelligent autopilot moves the drone into position and directs its TripleView head automatically.
Autonomous mode – define the area to map using the drone’s eMotion software. The software automatically generates the drone’s flight plan, then eXom takes off, flies, acquires imagery and lands itself (similar to senseFly’s fixed-wing eBee drones).

With so many unique features in one safe, robust platform, senseFly is pioneering innovation in the civil drone field. “We are thrilled to announce the eXom and look forward to demonstrating this next-generation platform to Intergeo visitors,” said Jean-Christophe Zufferey, CEO and co-founder of senseFly. “We designed eXom to be unlike any other rotary drone; a fully-integrated imaging platform rather than just a remote-controlled aircraft with cameras attached. This allows users to focus on their work, not on flying.”

Iain

@theUAVguy

http://www.kextrel.com

Which Aerial Platform to use for Precision Agriculture?

Which Aerial Platform to use for Precision Agriculture?

eBee Ag Drone With Case

In my previous post I discussed how UAV’s can help with Precision Agriculture. In this post I’ll discuss the platforms that can be used at this time, ranging from off the shelf complete packages, to do-it-yourself airframes.

So one thing to note is that no single platform is suitable for all applications. The type of platform is dependent on a number of factors such as land topography, area of coverage, environmental conditions such as wind, direction and cloud ceilings. For example a small vineyard with elevation changes in a mountainous region is going to require a different platform, than a large artichoke field which is flat and near a windy coastline. Both these scenarios require different platforms.

Multi-Rotors v Fixed-Wing

In general multirotors are great for small aerial PA projects, 0.2 sq mile. They have endurance of approximately 20 minutes allowing coverage of smaller areas, have good wind resistance to approximately 20 to 25mph dependent on model, can cope with rapidly changing land elevations, and can fly lower for higher resolution. Also the take-off and landing area requirements are significantly smaller. The downside as mentioned is their limited range, which means that for large areas multiple flights are necessary with associated image stitching and complication.

For medium to large areas, 4 sq miles, fixed wing platforms dominate. The reason is endurance, fixed-wings as the name suggest generate lift off their fixed-wings, so as long as they have enough forward motion to generate lift they stay airborne. In a multirotor all the lift comes from the motors and propellers. If both a multi-rotor and a fixed-wing use the same battery, the more efficient fixed wing will be able to fly much longer. Normally up to 3 times as long.

So what are desired requirements for an aerial platform?

Safety and Redundancy

Well for anything aerial safety is key, and the lesson learned from manned and RCMA (RC model aircraft), is that redundancy is key. On a multirotor, the lower the number of rotors you have, the more catastrophic the event if a motor or propeller fails. Losing a propeller or motor on a tricopter (3) or quad copter (4) will normally always result in a crash. Using Y6 (6), and hexacopter (6) formats allows for a motor/propeller issue, but for the platform to be landed. The same is true of X8 (8) and octocopters (8).

Another area of redundancy is servicing and repair. Multirotors as the name suggests are made from a number of motors which operate in tandem to control the flight of the UAV. Normally the motors are the only moving parts on a multirotor except for maybe a gimbal. As such there are less moving parts to fail. The safety concern with multirotors, is that they have no lift mechanism other than the motors and propellers. The problem here is that if the motors stop, they just fall out of the sky. On a fixed-wing, if the motor/s stops, the wing still generates lift and you can glide to a landing.

Now fixed-wing moving part failures tend to be catastrophic in failure, unless there are redundant actuators. On a generic fixed-wing airframe you have actuators that control roll, pitch, yaw and throttle. Normally that translates into two independent airelons for roll, two elevators which are normally joined for pitch and a single rudder for yaw. That equates to 4 actuators/servos and a throttle control. To increase safety this can reduce to two airfoil actuators and a throttle control. Here the pitch and roll are combined in what is termed an elevon system, where the left and right ailerons are moved in combination. Both airelons up induces a climb, both aileron down is a dive, left aileron down, right up is a right roll. Now if the left aileron is moved up and the right aileron is left neutral, the plane with roll left and pitches up. This type of control is normally associated with airframes that are called flying wings. To further increase safety, multiple actuators can be also placed on a single airfoil, as such if one fails, the other takes over as a backup.

So what we are doing here is reducing the number of moving parts that can fail, and where we cannot minimize anymore, then add redundancy in the form of parallel actuators or motors.

Another key area is auto-pilots, just like you Windows PC rebooting and installing updates without warning, you need to ensure you have a safety-critical autopilot. If you autopilot reboots in mid-air, on your multirotor the motors will stop and it will just fall out of the air, on a fixed wing it may glide off into the sunset. Other safety issues are flyways, this can be due to poor autopilot firmware, GPS glitches, power supply spikes etc. Ensure you are using certified autopilots with stable code, good supply distribution, and high quality GPS and even redundant GPS units. In some cases redundant telemetry, RC receivers and autopilots are also employed.

A final safety feature is geo-fencing. Here an invisible fence is placed around the flight path by the mission planning software. If a geo-fence is breached, such as due to a failure of GPS loss of lock, GPS glitching, lost telemetry link etc., that the platform returns to the takeoff site and either loiters allowing a manual landing or auto-lands.

Safety is key, this industries growth will be defined by how safe it is.

Spares

It’s great buying that cheap UAV or airframe from overseas, but what happens when you have a rough landing? Can you get spares readily? This is an important consideration, if you ding a wing, you don’t want to wait 2 weeks for international shipping. Makes sure you either have an inventory of spares, or have a nearby dealer who has a good supply.

Stability and Image Quality

It’s true that the fun focus is on the flying, but flying is only 20% of the overall work. The other 80% is flight preparation, post flight and then data retrieval and processing of the images. However you can have poor images due to poor camera choice, no gimbal or a badly stabilized camera gimbal, badly designed autopilot or inefficient stability algorithm, a badly setup multirotor with bad gain settings, poorly balanced propellers etc. All these issues can lead to inferior image quality. And as with most processes, if you put bad images in, you are going to get poor data out. As such although flight time is only 20% of the process, it is key to getting quality data.

So you need to look for a good camera which has approx. 12Mega pixel, with the best possible dynamic range, with integrated image stabilization. The cameras are normally modified with new filters for NIR etc. I’ll discuss cameras and modifications in the next blog. At present the go to camera is a Canon S110 with NIR using filters from people like Event 38. Other cameras such as the Canon SX260 and S100 are also used. You notice the predominance of Canon cameras, this is because they are easily modified for filters and updated with control software called CHDK.

For fixed wing operations having the camera hard mounted to the airframe is the norm. Normally due to the forward speed of a fixed-wing platform and the autopilot, it is normally flying wings level during image capture. On multirotors, due to wind effects, direction of travel, the airframe can be leaning into the wind/direction of travel, and as such a 2 axis gimbal is normally used. These gimbals can be servo or brushless, as this is still pictures a quality servo gimbal can work as well as a brushless gimbal, without the associated cost. The gimbal levels the camera and removes any autopilot sudden corrections.

Autopilots are very important for image quality, a poor autopilot can wander off path giving incorrect image overlaps, jerkiness in control response and just about spoil your day.

So based on the above information, I know there was a lot compacted into a small space, here are some picks for Agriculture UAV’s with some pros and cons:

Fixed-Wing Complete (with associated GCS)

senseFly eBee Ag https://www.sensefly.com/drones/ebeeag.html

Pro – Well integrated package using S110 cameras and PIX4D software. Very small.

Con – Integration costs approx. $25,000 including PIX4D software

Event 38 E384 http://www.event38.com/ProductDetails.asp?ProductCode=E384

Pro – Well sorted package based on 3D Robotics Aero, $2,399. $3700 extra for AgiSoft software

Con – Highwing design, more susceptible to damage, more moving parts

3D Robotics Aero https://store.3drobotics.com/products/3DR-Aero

Pro – Designed by 3DR around Pixhawk autopilot $1350, supported by Pix4D +$3000 annual

Con – Highwing, more susceptible to damage, more moving parts, no defined camera area

Ritewing Zephyr II with Ruby Autopilot http://www.ritewingrc.com/Zephyr_II_ARF.html

Pro – Proven design

Con – Ruby autopilot does not support waypoint navigation at this time

Fixed-Wing Airfarmes

Range Video RVJet http://www.rangevideo.com/en/18-rvjet

Pro – Very stable design for autonomous flight

Con – Long wing easy to damage, no defined horizontal camera area

Skywalker X8 as used by Robo Flight RF 1 http://www.roboflight.com/products/

Pro – Large stable flying wing, able to carry large payloads over long distances, has camera area

Con – Parts from overseas, very large

Phantom V2 Flying Wing http://pixhawk.org/platforms/planes/phantom_fpv_flying_wing

Pro – Small airframe, flying wing that can be taken apart, very stable, has camera area

Con – Parts from overseas

Fixed-Wing Autopilots (with associated Ground Control System and Mission Planning Software)

3D Robotics APM2.6 https://store.3drobotics.com/products/apm-2-6-kit-1

Pro – Established fixed-wing autopilot

Con – Running out of processing power and memory, surpassed by 3DR Pixhawk

3D Robotics Pixhawk http://3drobotics.com/pixhawk/

Pro – Carries on from where APM2.6 left-off

Con – Newer architecture

Roberta Goose http://www.robota.us/Goose/dp/B00EGT0ZCY

Pro – Very reliable, used by Gene Robinson for Search and Rescue

Con – Expensive $3995

Airware http://www.airware.com/

Pro – Modular autopilots for who range of UAV’s

Con – Very Expensive

Complete Multirotor for Scouting (with associated GCS)

3D Robotics Iris https://store.3drobotics.com/products/IRIS

Pro – Integrated proven design with support

Con – In-demand

DJI Phantom 2 Vision+ http://www.dji.com/product/phantom-2-vision-plus

Pro – Integrated proven design with support

Con – In-demand

Complete Multirotor with Lift capability for NVDI Cameras (with associated GCS)

3D Robotics X8 https://store.3drobotics.com/products/3dr-rtf-x8-2014

Pro – Proven Pixhawk X8 copter with PA mission planning and Pix4D software support, $1350

Con – Needs more hands on experience required with mission planning

3D Robotics Y6 https://store.3drobotics.com/products/3dr-rtf-y6-2014

Pro – Proven Pixhawk Y6 copter with PA mission planning and Pix4D software support, $1000

Con – Needs more hands on experience required with mission planning

Aerialtronics Zenith http://www.aerialtronics.com/products

Pro – Very professional high quality design

Con – Expensive at $25,000

DJI S800 http://www.dji.com/product/spreading-wings-s800-evo

Pro – Very professional high quality design

Con – Expensive at $10,000

DJI S1000 http://www.dji.com/product/spreading-wings-s1000

Pro – Very professional high quality design

Con – Expensive at $25,000

Multirotor Flight Controllers (with associated Ground Control and Mission Planning Software)

DJI A2 http://www.dji.com/product/a2

Pro – Established highend multirotor autopilot

Con -Cost

DJI Wookong-M http://www.dji.com/product/wookong-m

Pro – Established multirotor autopilot

Con -Cost

DJI NAZA V2 http://www.dji.com/product/naza-m-v2

Pro – Established entry level multirotor autopilot

Con – Recorded flyaways due to GPS glitching

3D Robotics APM2.6 https://store.3drobotics.com/products/apm-2-6-kit-1

Pro – Established multirotor autopilot

Con – Running out of processing power and memory, surpassed by 3DR Pixhawk

3D Robotics Pixhawk http://3drobotics.com/pixhawk/

Pro – Carries on from where APM2.6 left-off

Con – Newer architecture

OpenPilot Revolution http://www.openpilot.org/products/openpilot-Revolution-platform/

Pro – Open source firmware, proven

Con – Not as widespread as other autopilots at this time

Airware http://www.airware.com/

Pro – Modular autopilots for who range of UAV’s

Con – Very Expensive

So the question is do you spend $25,000 on a senseFly eBee AG or do you buy a 3DR Aero for $1350? Same with the multirotors, do you spend $25,000 for an Aerialtronics Zenith or $1350 for a 3DR X8. I guess it depends on how deep your pockets are.

Thanks for reading, next posting will be about cameras for PA.

Regards

@theUAVguy

http://www.kextrel.com

iain.butler@kextrel.com