A little bit of theory: How do Quadcopters fly?

How do Quadcopters fly?

 

Quadcopeters as the name suggests use four motors to fly. Two motors rotates in clockwise direction and another two in counterclockwise direction. In this way their are balancing quadcopters rotation. When four clockwise motors would be used on the copter, it will start rotating always in clockwise direction and if only four counterclockwise motors copter would be rotating in counterclockwise direction. Having two pairs of contrary motors cause Quadcopters to stay in place. Peacefully hovering above ground. When speed on all motors equally increases or decreases drone will vertically take-off from the ground or

Good to know: lift, drag and thrust.

Piloting

 

Quadcopter or any other copter, airplane or object can be rotated around three axis, they are called roll, pitch and yaw.

  • Rotation around the front-to-back axis is called roll.
  • Rotation around the side-to-side axis is called pitch.
  • Rotation around the vertical axis is called yaw.

Airplanes use ailerons, rudder and elevator to rotate around one or another axis. However copters doesn’t have them instead use four motors with propellers. Airplanes are more intuitive to understand but quadcopters are not as complex as they look.

 

Roll, Pitch & Yaw

Always to rotate drone through one or another axis two motors on one side need to speed up and other two motors on opposite side must be inversely changed.

Roll axis

 

To lean drone to right both left motors speed need to be increased and speed of both right motors decreased. To lean to left both right motors speed should be increased and left decreased.

Pitch axis

 

 

Rotating a drone thought pitch axis requires speed change of back and front motors. To lean forward speed of ‘front’ motors need to be decreased and speed of ‘back’ should be increased. To lean backward speed of ‘front’ need to be increased and ‘back’ should be decreased.

Yaw axis

 

 

Yaw axis full move explanation is a little bit more complex then other two axis. I would like to explain the basics here but if you would like to know more, just google it. Also good thing is that all flight controllers have this knowledge injected to their ‘brain’. In the nutshell, to turn drone left or right two diagonally across motors must speed up and second two should slow down.

Setup Raspberry PI (+navio) Raspbian and Flight Control Software (Autopilot)

 

Setting up Raspberry Pi is very easy and you can find a lot of guides step by step on the internet. By just to make it easy for you I will add quick guide of Raspberry Pi Raspbian OS installation.

 

Raspbian OS Installation

 

1) First download: Raspbian Operating System ISO file

Raspbian

2) Download & Install: Win32diskimager Tool which Installs ISO on microSD card)

https://sourceforge.net/projects/win32diskimager/

3) Upload Raspbian ISO to SD Card using win32diskimager

 

Flight Control Software (Autopilot)

 

There are two main free flight controllers Ardupilot and PX4. I think they both are good. They have very strong community which as I have noticed works all week to make their software as best as possible. Ardupilot is more mature flight controller which I think also supports more platforms rovers and subs. On the other hand PX4 as I have read is more advance in accordance to multicopters plus has more modern architecture which uses 32bit CPU and supports more peripherals. But also Ardupilot has much much better documentation so for users which are not very tech people it will be much easier to do anything related to drones. As it also contains some documentation about drone build.

My plan is to start with PX4 and see how it will work for me. I will keep you blog posted. If not I will test Ardupilot. I will be also working on their code so I could have some other thoughts later which I will post about. So let’s see how we can install both software on raspbian with navio2.

 Ardupilot Flight Control Software Installation

 

Whole installation process you can find on emlid.com docs page at:

https://docs.emlid.com/navio2/Navio-APM/installation-and-running/

 

 PX4 Flight Control Software Installation

 

PX4 support Navio2 board from I think couple months so there is not much guide how to install it best link I have found is the one below.

https://dev.px4.io/hardware-rpi.html

 

Good luck,

Radek

 

 

 

Investigation of adequate drone. #Part 2: Drone parts – my build.

Last week I started “Investigation of adequate drone” series. I will share my whole Do-It-Yourself drone experience. Today we will go through quickly through elements quadcopter drone is build from.

 

Quadcopter

Quadcopter is a great type of drone to start with. Is more agile then hexacopter or octacopter as it’s smaller which makes it more easier to control and safer then it’s other bigger or more complicated brothers with doubled propellers.

It is good to remember that propellers are like little knifes which can hurt, so be careful!

Finally quadcopter I think is the cheapest look-like-popular-drones copter overall starting from frame price to number of propellers.

All my future blog posts will be related to quadcopter drone as that’s the drone I bought.

 

Drone elements

 

Below I would like to list all parts I think are necessary to build a proper drone. Also giving you name of element I have bought as I know now how hard it is to build your own drone. I was strangling, comparing, thinking and planning all week to finally order this what is in below table.

When I was ordering my quadcopter I was really close to skip couple elements like e.g. power distribution board or very useful mounting foam and other little but sometimes critical elements. Unfortunately, other blogs I have read about building a drone doesn’t include such as ‘not importans’ elements. Which I think is wrong as without them assembling the drone still will be possible but much harder to do.

Below is the table from my excel file which contains my drone elements. Actually it contains everything related to my very first drone assembly including threadlocker and heat sink tubes.

Table of my drone elements

Elements type What I bought
Multicopter frame F450 Quadcopter Frame with integrated PDB
ESCs CICADA BLHELI_S ESC (30A) – BB2 UT EDITION
Motors MT 2216 810Kv Muticopter Motor
Propellers 9443 Self-locking Propeller Pack
Propellers 10×45 Propeller Set Carbon Fiber (discount)
6/9+ channel RC transmitter FLYSKY FS-I6 TRANSMITTER WITH FS-IA6 RECEIVER
GPS Mount Foldable GPS Mast Mount
LiPo battery Tattu 1300mAh 14.8V 45C 4S1P Lipo Battery Pack
LiPo battery GENS ACE 3300MAH 11.1V 25C 3S1P LIPO
Charger SKYRC E450 LIPO/LIFE/LIHV BATTERY CHARGER
Wiring Navio Wire pack for Navio2
Flight Controller board Navio2
GPS Antenna GPS/GNSS antenna MCX for Navio
Power Module HIGH VOLTAGE APM POWER MODULE WITH 3A UBEC
Anti-vibration bed VIBRATION DAMPING MOUNTING SET
Propellers guard 5″ PROPELLER GUARD PACK
Cables Male XT60 wire – 10cm
Cables Female XT60 wire – 10cm
T-plug cable MALE DEANS / T-PLUG WIRE – 10CM
Adaptor Male T plug to Female XT60 Adaptor
Legs HIGH LANDING GEAR FOR F450/SK480/F550
SD  16GB microSD

As you can see I didn’t add any gps antenna and microsd card as I had them at home, but you can easily look for them at any shop. Also I haven’t ordered threadlocker blue, battery holder and heat shrink tubes as I bought them in local store.

Some parts could be unavailable in store you will be buying from, then I would recommend to find similar elements but from other manufactures. Trust me it is hard to find a copters related store which will have everything you want. Most of the time it is a hunting for the best equipped store which have as much items you need.

My order

I order everything from Unmannedtech as they had elements all really wanted plus some others in decent price. In my case I was looking for store which will have F450 Quadcopter Frame, not to expensive carbor fiber propellers, navio2 board in good price and decent cheap transmitters. Which I all found there. But as I live in Ireland it was a priority for me to order from one shop from Ireland or UK. If you leave in UK or another in EU where you have more diy shops or you have couple weeks to wait for an order you will be might be able to lower the costs by ordering from couples different stores

Investigation of adequate drone. #Part 1: Online stores.

Autonomous Drone project post

I wish you enjoyed my introductory post if not I am invite you to read it before this post. It contains the plan for this project.

 

Ah, the investigation… It took me half Saturday and half Sunday already. And to be honest I don’t know which drone I should buy not to mention which stabilization and control hardware I should use. I will try to find out it next week and I will let you know in my next blog post.

Today I will share with you my experience with drones and drone related parts online stores. I will try to summarise what I have learned in the last two days.

 

During my search I have noticed that significant number of online shops don’t keep their stock updated. I am looking for pretty small drone to start with, which will cost me maximum £400 including everything. But unfortunately in drones world it is not much. So when I have visited five first websites they had their stock empty with good but still cheap drones or the shipping time was around 14-28 days.

That being said, some people order drones from Chinese online retailers. In my opinion drone is a pretty quick thing with crazy fast rotating propellers and when bought cheap could do more harm then pleasure. Some with drone controllers, actually especially them buy at some well known store.

Selection:

I have found two looking good online stores in UK and Ireland but also I think it is really worth to check list of stores recommended by Ardupilot as I believe they have immensely more experience in it then I do:

Online stores recommended by Ardupilot

Stores I have found and I hope I will order from are UnmannedTech UK and RadioControlled ROI as they seem to have couple interesting drones and parts. But I will let you know as if they will have too many things out of stock I could order from other.

Kits:

Another way to buy a diy drone is to buy whole kit with flight controller like Erle copter but it’s especially when adding more parts can grown quickly to couple hundred of pounds.

Building own drone:

Last way is to build your own drone. Drone could cost a little bit more but will be equipment in parts that are ideal for your drone. But if don’t have much experience in drone architecture it might be better to purchase a low cost drone at the beginning. Then in the future build your own dream drone.

Let me know in the comments what you decide to purchase.

Introducing “Autonomous Drone” – my Get Noticed 2017 apparatus.

The Autonomous Drone is my new motivator-project to do a little bit more after work hours. An overall idea is to build a drone which will be able to do couple different things.

 

Plan:

First part:

First thing on my plan is purchasing a drone. This sounds easy but is not. DoItYourself drones need to be assembled manually, you need to carefully solder it and screw everything as manual says. Also it is good to plan what other parts you would like to equip your drone with. Like battery, flight controller, radio receiver, camera and many many more. And here it starts to be a little bit tricky. Drone need to be balance as best as possible and when you are assembling it you need to check if e.g. battery should be more on the back or maybe at front to balance the drone.

Second, ah silly thing but the drone will need to fly, finger cross everything is connected.

When will be able to hang in the air, just hover for couple minutes. I will start working on small WiFi controller.

Then drone firmware also will need to be extended with wifi controller code which will be able to understand wifi controller commands and transform it to real drone moves.

When all of this will be finished then will be a best time to start working on autonomous… Oh no, actually drone will need to be extended with some telemetry before autonomous. Will be extended with GPS module, accelerometer,  gyroscope, distance sensors and probably couple more.

The one thing I haven’t yet found-out is how to measure drone displacement inside a room when there won’t be a GPS signal obtainable. Probably I will need to work on some anti-collision system.

Perfect, we have everything, we can finally start working on autonomous code? Assuming all above sensor are communicating with drone control unit and they are working correctly, y… maybe, but no…

Second part:

Because, the second part of the project is cloud (Azure or AWS). All sensors data will need to be aggregated and pushed to Azure where some analysis will be done. I am planning to use cloud to correct my autonomous code based on analysis made. I am not yet sure how but I will find a way to do it. In sum it is always better to start collecting data from the beginning of the work on something then later without having view on full process from the start to ‘now’.

When it’s done, yes I can…! No, I can’t… I forgot about one more thing. On a windy day or with people in the room, drone could be randomly moved or even be turned over. And this displacement need to be included in real-time flying calculations to immediately make a correction on the flight plan.

Come on! Let’s do some work on autonomous code.  Okay, okay! We can start now. Ah relief, happy days!

Autonomous part of the project will be the most complicated part but I cannot wait when I will start working on it. I have hope that above tasks will be finishes in next couple weeks/free weekends. So I could start coding as soon as possible!

I hope you enjoyed my preface. If you have some questions and comments please feel free to ask. I started simplebug.net blog to share my experience with you.

Good luck,

Radek