Hi guys,
I'm a new member in the DIYDrones family, and this is my first blog post sharing some of the monocopters that I've built as a hobby project.
I started making my own monocopters back in 2011 after watching the inspiring work on monocopters from University of Maryland, Lockheed Martin and ERAU. I was fascinated with the way the monocopter flies without a fixed heading and yet controllable. So I started trying to make one out of some small and cheap parts I could find at that time, using the UMD design as a reference.
I was kind of surprised at that time that it managed to take off. Here's a video that I took:
Excited with the result, I immediately began to work on the control. With great help from the 2008 MIT paper "Fly-by-wire Control of a Monocopter" by James Houghton and Woody Hoburg, I tried to implement the equations presented in the paper into Arduino code.
The microcontroller chosen was Teensy 2.0 for its relatively small size. MicroMag 2 was used as the sensor for heading reference and a LPY5150AL was used for RPM sensing. Here are some photos of the board I made to house the electronics:
The motor used was Turnigy 1400 Brushless Indoor Motor 4500kv paired with a small 6 Amp ESC. Props used is GWS EP-3030 and battery is 2S 450mAH LiPo. Receiver used was FrSky D4R-II with PPM output and MKS DS480 was chosen for its speed.
The construction of the frame was improved by utilizing Carbon Fibre sheets, built in a way very similar to the UMD prototype. Electronic components are mostly secured with heat shrink tubes and the motor is mounted on a square aluminium tube which is secured to the carbon fibre frame with screws. Some photos of the final build:
Here's a video of the first successful controlled flight indoor:
Here's another video of indoor flight:
The prototype weighs 90 grams and hovers for around 5-7 minutes.
After the first successful prototype I wanted to add more sensors but was limited by the lack of space for more electronics. So this time I tried to make another prototype with Lockheed Martin's design.
A 3D model of the wing and body of the new prototype was created with SolidWorks and subsequently printed using the SLS 3D Printer, Formiga P100 in the Fabrication Lab in SUTD. Here's a SolidWorks render and some photos of the assembled prototype:
A RGB LED Module that I got from a friend is included in this prototype for some POV coolness.
Here's a video of the second prototype:
As of now a monocopter, except for its cool factor, has not much of a use.
However I hope my post will be helpful for those looking to make one of this fascinating little fliers :)
Comments
Is there any way I could access your solid works design. I am attempting to build a similar design but not very good with solid works. Please let me know, thanks!
Hi
you had done a good work.
I'm working on same monocopter and something bother me about it. how can I control it's altitude?
I think your doing it with changing motor RPM. but how you know what's the suitable RPM ?
man! this is awsome stuff, love the led's!
This is great!
That's just SO awesome!! Great job! Hope to build one myself someday soon :D
I'm new to this and it is very cool! I am curious if one could use this as a main rotor for a helicopter and thereby get a stable platform. I read that if a helicopter main rotor is self powered, a tail rotor is not needed.
Impressive !
Actually the first one who built a monocopter was nature. Indeed what you have built mimics (maybe you did not realize it) the fruit of the "ash" tree which is made of a bulb and a wing. When it falls from the tree it flies as a monocopter away from the tree.
The following picture shows how it flies by spinning around its CG:
@ Ying Hong
I left ERAU before the team integrated the wii sensor so I don't know how well it works. You should take a look at the WiiDAR project. They show how to make a lidar using a wii controller.
As you know its all about the weight. More weight = higher rotation speed. This makes the control harder. I'm currently using a Sharp 2y0a21 sensor because of its weight. My monocopter is only 60 grams. My navigation relies on staying close to the wall and using it as a reference for orientation (in combination with the magnetometer).
If you are not in a rush to do wall avoidance. I think you are better off with a LIDAR lite sensor. It is only 12 grams :). The only issue is that you have to pre-order them. I'm waiting to get my hands on one.
@mP1 Servo speed is critical. I changed to a "magnetic servo" (its basically a micro solenoid) because of its speed.
Really cool. Have you tried flying dead stick from altitude? If the descent rate is slow enough i could imagine this being used as a guided, air sampling device. Drop a few from a plane or larger drone and let them descend slowly through the air and back to the landing zone. Maybe add some of this camera technology too: http://www.serveball.com/
Thanks guys! I'm aware of Jack Crossfire's great work on monocopters, in fact I've been following his blog since he started making monocopters.
Currently the electronics on board of the new prototype are pretty limited, I'm planning to upgrade the electronics to include GPS and barometer for some autopilot features. Considering using PX4 interfaced with the sensors I'm using.
Would also like to have features such as wireless upload of images for the POV display in flight. I think it will probably take another year before I complete these tasks and come up with something more useful and presentable.
@JR
Great to hear from you! The ERAU design is really well done and I'm considering using EDF for the next prototype as well. I saw in the 2010 paper that you guys are using a PixArt sensor from the Wii Mote for range finding? I will be trying to use the LIDAR from the Neato to do the wall avoidance, but it's a little bit heavy at 30 grams. What do you think?
@Mustafa
Thanks for your suggestion! However I'm not sure whether there will be any demand for things like this. There isn't much it can do with it's continuously spinning body and it will probably take much more work before it can be considered for Kickstarter.
@mP1
That is the reason that I chose to use servos that are normally used for hell tail rotor. The fastest I could find was MKS DS95i. However I'm not sure whether it can make do with a slower servo.
@Quadzimodo
Theoretically with a single rotor blade it should be more efficient than heli rotors with two rotor blades due to one less blade tip vortex generated. However I believe that efficiency can only be achieved with more optimization in the design to reduce drag. As the prototype with LEDs rotates at a fairly high RPM of around 720 rpm and weighs around 250 grams, I would not consider it safe enough to be flying around people, perhaps the first prototype would do better as it's much lighter. I feel that the current prototype is not good enough yet which is why I'll be improving on the design and feature before considering selling it.
@Oliver
The prototype with LEDs spins at around 720 rpm or around 12 rotations per second during hover.
@Rana
As the body is constantly spinning, it won't be easy to get any useful video and images from a monocopter. However Lockheed Martin has achieved this by synchronizing the camera frame rate with the rotation rate of the monocopter. I believe Jack has also worked on this before. There are definitely downsides as this method can only work well enough in areas with good lighting condition and it will never match the kind of quality that you can get with multirotors. This is why I'm thinking of other uses like the POV LED display, which as mentioned by Quadzimodo, has potential uses in advertising and communications..
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