This project was started in , electronics and control loops. Because I always need a cool project to learn new things, it was clear that something that can fly had to be built.
The project started as a "tricopter-only" project, but as I wanted to build smaller vehicles with more payload capacity, I decided to make some quadrotor, hexacopter and Y6 hexacopter firmwares too. My main interest is to build very small MAVs that fly as good as larger ones (or even better) and that can be controlled by wireless video link. I also experimented with autonomous flight in GPS-denied areas (video), and with GPS assisted autonomous hover (video).
-- William

Contact: Shrediquette @ g m x . d e --- All content published under CC Attribution-Noncommercial-Share Alike 3.0 Germany

QRC Progress - Part I

Tonight, I assembled the first parts... Everything seems to fit as expected :)



QRC5 design

The QRC5 incorporates some ideas that I had when I was designing the GEMiNi and the HEXO+. First of all, it's not a hex- or trirotor anymore, it is one of my first quadrotors... Personally, I think quadrotors are a bit boring. But there are many FPV racing events coming up, and I am sure that most of them will have several different regulations and limit the battery voltage, the amount of motors or the rotor diameter. The most 'standard' racing copters are quadrotors, they have 3S batteries and 5" props. I am sure that they will get their own racing class. I would like to be able to compete with them, therefore I decided to design a copter for this standard class, even when I am not the biggest fan of quadrotors or racing rules and classes.
The Shrediquette QRC5 fits the 250mm quadrotor racing class
Tilted propellers have become popular since the GEMiNi was presented, and in my opinion they really have an advantage. The aerodynamic drag is reduced quite a bit in fast forward flight. And, also important, the drag is increased in slow flight and during braking. This part becomes important on racetracks with sharp corners.
The QRC5 does not really have tilted propellers, but a tilted body (which is very similar). When only the body is tilted, there is little vertical offset between the propeller disks, which seems to be advantageous for the flight control.
The body is tilted 30° backwards, leaving the propellers on a relatively similar plane
The arms that connect the motors with the body are flat plates that are aligned with the dominant flow direction: Below the rotors, the flow will be 95% perpendicular to the rotor disks, no matter how fast we fly. The flat plates have very little drag, which will increase the maximum flight speed. Each of these plates are made from a three-layer sandwich (glass fibre, end grain balsa, glass fibre). This results in extremely rigid and lightweight arms.
Top view: The flat arms are parallel to the main flow direction
I'll again use the 'CCD-Killer' CMOS camera by Fatshark. For me, this is still the best camera, even much more expensive CCD cameras don't give such a great image. The camera is tilted 13° up (with respect to the propellers).
The CCD-Killer sits between the arms

Shrediquette QRC5 renders

Just ordered the first 3D printed parts on Shapeways.com :-D
Here are some pictures of the racing quad:
 





Shrediquette QRC5 (5 inch / 250mm tilted-body FPV racing quad)

Hi!
FPV racing is becoming really popular (yaay!), and I will be attending a nice FPV race event in about two months in Saarbrücken (http://fpvairrace.de/). I will compete with the GEMiNi, and eventually with a new tilted-body quad design with 5" props and MN1806 motors. I am posting some very early and not so interesting concept pictures. I am doing this to keep my motivation high: My time for the hobby is still severely limited, but I really want to build some new stuff - and this post helps to remind me of what I want to do... As soon as there is some progress, I'll update this text.

 



video

PhD thesis finished


Recently, I finished publishing my PhD thesis. The public defense will take place on the 31. of october 2014. Although my thesis mostly deals with aerodynamics and flapping flight, there is one chapter that could also be of interest to the readers of my multirotor blog:
Chapter 5: Micro Air Vehicles - linking aerodynamics with application
Here is the full thesis.

TBS Gemini preorder started!

The pre-order for the GEMiNi recently started (Monday 13. Oct., 10pm HK time, 7-10am USA, 4pm EU, midnight Australia), and I guess you might need to be quick to get one...
The link to the pre-order:
http://www.team-blacksheep.com/gemini

2nd place in the IMAV 2014 competition!


This year, the 'International Micro Air Vehicle Conference and Flight Competition' (IMAV2014) took place on the 13th of August in the Netherlands. I am very happy to announce that together with my team (called 'Dipole', consisting of Prof. Klaus-Peter Neitzke, Dr. Hans-Peter Thamm and me = William Thielicke), we won the second prize in the IMAV competition!


Fifteen international teams accepted the challenge and tried to score points in the simulation of a major natural disaster inside a small artificial village. Several tasks had to be solved during a 30 minute time slot: Creating a stitched orthophoto of the whole village; flying through the village and identifying house numbers and survivors inside the houses; observing a given spot; entering a two-storeyed house and flying through the rooms while identifying objects in the rooms (see the detailed rules here). Points were awarded for each of these tasks, and summed for the final score.

Our team used three different multirotors in parallel, including my 'GEMiNi' hexrotor, an 'Alpha' quadrotor by Klaus-Peter Neitzke and the larger 'Geocopter' by Hans-Peter Thamm. This year, the 'Alpha' and the 'GEMiNi' were again the smallest vehicles of the competition. While the 'Geocopter' flew over the village autonomously creating a high-resolution orthophoto, the 'Alpha' and 'GEMiNi' went through the houses of the village to identify some house numbers. This was pretty challenging, because we had to use 5.8 GHz for the video link, and there were a lot of obstacles between the antennas, making the video quality very poor. These copters also entered a large house and flew through many rooms. This was not as easy as I thought, as there was a strong wind that was clearly noticeable also inside the house (because the windows were open). The space in the rooms was very limited, and we didn't know anything about the floor plan and potential obstacles before we entered the building.

The first prize went to the team of the National University of Singapore. They came with eighteen people and ten copters. Most of these copters were equipped with impressive laser range finders and other fancy sensors. This team really deserved the first prize, they did a great job!

Here's the scoring of the first three teams, the scoring of the other teams can be found here.

1st prize 

National University of Singapore (Singapore) points: 683
Onboard automatic image stitching, onboard number recognition(*), onboard autonomous laser-based room navigation, onboard computer vision based precision roof landing, autonomous takeoffs, autonomous landings (*), onboard computer vision based 7-segment digit recognition (*), autonomous flying WiFi-relay.

2nd prize 

Team Dipole (Germany) points: 425
Smallest MAV's of the competition. Very talented FPV flight with many take-off, precision landings, reading house numbers, visiting 18 indoor rooms (several double and not counted), recognizing 16 indoor objects correctly. Geocopter auto-take-off and flight, precision auto landing and partial high resolution ortophoto.

3rd prize 

Ecole Nationale de l'Aviation Civile (France) points: 189
Autonomous takeoff, Best overall photomission, all blockades visible, full village high resolution map at 6cm/pixel, autonomous computer vision based 7-segment display reading (**), longest correct observation string, autonomous roof landing (*), reading house numbers with many ARdrones in autonomous flight. Several autonomous landings.

(*) Item attempted but either failed, or needed manual flight, or not according to competition rules.
(**) Item attempted in autonomous mission mode, but human intervention was needed and it got scored in autonomous flight mode.

Here are some photos of the event:

The GEMiNi entering a building
Klaus-Peter and a judge
Award ceremony
The trophy
NUS UAV Research group (1st place, Singapore)
NUS UAV Research group (1st place, Singapore)
Williams FPV flight
Location of the competition
I would like to thank the organization committe, it was really great fun - again! We're looking forward to next year in Aachen!

TBS GEMiNi

Letting the cat out of the bag 

The TBS GEMiNi is a small hexrotor that is meant for fpv racing. The frame is based on my Shrediquette GEMiNi that I developed in spring 2013. Team Blacksheep (Trappy, Riscyd and Perna) contacted me a while ago, and we started to modify the design in order to improve it further and to make it more user and crash friendly. After some information had already leaked before the offical release (may it be on purpose or not... ;-D), the new TBS GEMiNi has now been officially announced on fpvlab.com. This means that you can very soon buy the GEMiNi multicopter!

 

Features of the TBS GEMiNi

  • Forward-tilting motors for efficient, high speed flight
  • Built-in FPV camera (TBS ChipChip V2)
  • Optional HD camera (Mobius Action Cam)
  • CORE OSD/power supply with integrated current sensor
  • Ready for long range FPV
  • Custom 4A ESCs with SimonK firmware
  • Custom T-motors
  • 4" propellers
  • Motor distance: ca. 215 mm = 8.5"
  • Taulabs Quanton-based flight control
  • Crash-friendly, yet integrated layout
  • Top speed: About 90 km/h
  • Weight: About 340-370 g
  • Price: Less than 600 USD


The package includes the TBS Gemini main frame + plastic parts, a canopy for race and film, the motors /  ESCs / props, a flight control, a pre-configured CORE PNP25 (optionally upgrade to CORE PRO), a FPV camera, a TBS BOSS 5.8GHz (optionally upgrade to 2.4GHz), a 3S battery and a fancy carrying case. The GEMiNi can be ordered by end of august, and it will be shipped by late september.


What about the tilted propellers and the canopies?

On the GEMiNi hexrotor, the motors are tilted 10 degrees forward in order to decrease the angle of attack of the copters body in forward flight, which decreases the net aerodynamic drag in fast translational flight. Additionally, the canopies help to reduce the drag coefficient of the copter. I measured the effects in a wind tunnel using a two-axes force balance, and the results show that the drag is reduced by something around 30%. See my detailed wind tunnel measurements here.
The handling of the copter is not affected as long as the IMU is aligned parallel to the propellers (you can also rotate the IMU by software via calibration). It seems likely that tilted propellers might become more popular in the future, similar to my 2010 "design invention", the spider frame.

 

What are the differences compared to the Shrediquette GEMiNi?

On the TBS GEMiNi, we don't use my own flight controller (Shrediquette Xmega MPU60X0), but a Taulabs Quanton based controller. In "heading hold" (= angular velocity control), it feels very much like my flight controller. But the Taulabs also has a "stabilize" mode (= angle control), which makes it more suitable for the broader audience and for beginners. Taulabs additionally has a large number of  interesting features that I like a lot.
Furthermore, the TBS version is slightly larger and it has a canopy with a larger volume. This allows for using larger batteries, a broader range of video transmitters and larger receivers (hence people can install the gear they want). TBS selected some very nice and light custom T-motors, these are much better than the cheap turnigy motors I initially used. The ESCs were also developed by TBS epecially for the GEMiNi.

On my balsa/glassfibre sandwich chassis, the motors are mounted with 10 degrees tilt by using some preliminary construction. TBS had the great idea to deform the whole arms in order to get the 10 degrees tilt. After some tests, they however decided not to use a sandwich frame.
There are also no LEDs on the canopy. This is because it is team black sheep that produces the copter and not team christmas tree sheep. But LEDs can easily be added to facilitate LOS flight.
For me, the most important difference is the 4S capability. The ESCs I had to use in the Shrediquette GEMiNi were actually designed for 2S and I was using them at 3S. The custom TBS ESCs allow to use 4S (which I do all the time), that makes the TBS GEMiNi pretty fast.


The most important question: How to convince your wife that you need to get the TBS GEMiNi...

I started working on the GEMiNi while it was clear that I'd soon become father of twins. So I decided to make something beautiful and dedicate it to my gemini girls. The idea was to sell some canopies and invest the money in diapers. Now, I am extremely happy with the result (the girls are just awesome), and each TBS GEMiNi somewhat actively contributes to bringing them up. I am sure that is something your wife would support :-D


GEMiNi girls on my custom longboard

12" multirotor propeller tests

Recently, I tested some 12" propellers as I want to make a 12" hexrotor (nothing special, existing 3rd party frame). There are some different opinions about these propellers, but I was missing a direct comparison. I tested 3S (12 Volts) and 4S (16 Volts) and measured the thrust and the current on a test stand, simulating hovering flight. I used a RCtimer HP2814(3536)-710KV motor and an AfroESC 20A slim speed controller.

Here are the props I tested:
The propellers under test: APC Multi Rotor 12x4.4" ; Xoar Electric precision 12x4" ; Maxxprod EPP 12x4.5" ; Aeronaut CAM Carbon light 12x5" ; Graupner E PROP 12x6"
The results clearly show that the popular Graupner E PROP isn't really the first choice for hovering. It requires about 13% more power than the Aeronaut prop for the same amount of thrust during hovering flight. I think the chord length is too small close to the tip (I know that high aspect ratio wings have less induced drag, but here, other effects seem to dominate). The Graupner propeller also makes much more noise than the Aeronaut prop - which is the most quiet prop and also my favourite propeller. Interestingly, it has the largest (mean) chord length and the largest blade area of all props I tested. The APC multirotor is very similar, but has a higher weight. The Maxxprod is not stiff enough for these motor speeds and really shouldn't be used for heavier multirotors. I included it just because I had one lying around. The Xoar wood propellers are really beautiful, very well manufactured and light, but they have a pretty thick airfoil.
Here are the measurements:
Thrust and power at 3S (12 Volts)

Thrust and power at 4S (16 Volts)
The weight of propellers is also pretty crucial, as lighter propellers enable faster prop accelerations and decelerations which is advantageous for the flight stability. Here are the weights:

Graupner E PROP 12x6"21 g
APC Multi Rotor 12x4.4"22 g
Aeronaut CAM Carbon light 12x5"17 g
Maxxprod EPP 12x4.5"9 g
Xoar Electric precision 12x4"16 g

So, my choice is the Aeronaut CAM carbon light propeller (they exist in quite a number of diameters).

"Die Große Show der Naturwunder" - some images...

I found some images of my TV show appearance (to be broadcasted on 31.07.14) in the web:
Images taken from TVinfo.de (note to the copyright owners: if you don't want to see your images here, drop me an email!)
Hosts and celebreties
Yogeshwar and me
GEMiNi flight in the studio
Quiz show elements

Die große Show der Naturwunderam 31.07.2014 um 20:15 Uhr auf ARD Heiß her geht es diesmal in "Die große Show der Naturwunder". Frank Elstner und Ranga Yogeshwar präsentieren ein geniales Löschmittel und einen neuartigen Flugroboter, der die Natur zum Vorbild hat.Zu Gast sind Comedian Guido Cantz, die Schauspielerinnen Stefanie Stappenbeck und Marie Bäumer sowie Fernsehkoch Horst Lichter. Sie stellen sich den Quizfragen, müssen aber auch außerhalb des Studios ran.Bildvia TVinfo

IMAV 2014 !


The 2014 International Micro Air Vehicle Conference and Competition (IMAV 2014) will take place on August 12-15 in Delft, The Netherlands. I am very happy that I can join this event again this year (after my longer 'baby-break' last year). Just as in the previous IMAV competitions, I'll team up with Tumba. He will use several autonomous and FPV-controlled "Alpha" quadrotors and I will take some FPV BOLTs and GEMiNis with me. This year, the competition is especially fun, because the organization committee from TU Delft decided to combine the indoor and outdoor competitions in a single event. Tasks include to create a photomap of a village, detect obstacles, street numbers and open windows, and to finally enter some houses and explore the rooms. This might be pretty challenging, depending on the wind conditions and the video link quality. You can have a look at the competition rules here.
I am very much looking forward to the event, and I expect to see a lot of very interesting and great autonomous systems from different teams all over the world!

The BOLT Y6 hexrotor
The GEMiNi FPV racing hexrotor


--> Results in this post here! <-- a="">

HEXO+ autonomous aerial cam, kickstarter campaign

Maybe you've already heard of the HEXO+ follow-me copter. The kickstarter campaign recently ended and it was really successful. Check it out here:

HEXO+ on Kickstarter

As you might already guess from the look of this hexrotor, I was involved in designing the airframe and selecting the electrical components for this project. Here are some pictures of early prototypes:


The idea was to make something pretty aerodynamic. The booms are flat plates (each is a very stiff and light sandwich of glas fibre / balsa end-grain / glas fibre) that are arranged parallel to the airflow of the propellers (8"). They hence have very low aerodynamic drag, similar to the body of the copter which is tilted 30° with respect to the propeller plane. Unfortunately, my time for supporting the development of the HEXO+ project will be very limited in the future. But as I really like these kind of projects, I'll try to stay involved somehow.

HEXO+: Your Autonomous Aerial Camera -- Kicktraq Mini