02/16/2017 at 11:33 •
Hi, unfortunately due to a lack of resources this project has been postponed for over a year, I hope to purchase the equipment I need this summer to work on version 2. A 3D printer would be a good start. It won't take long to build.
01/25/2017 at 22:46 •
IN NEED OF SUITABLE FABRICATION FACILITIES
The design for project T has been improved and parts have been purchased but fabrication will not start until I have found suitable facilities so I have postponed this project for a year.
I am looking to get this project finished!
01/25/2017 at 22:43 •
I'll always miss version 1
01/25/2017 at 22:41 •
I've attached videos of version 1 of project T performing some control & propulsion actions for demonstration purposes.
As you can see having telemetry output with a measly Atmega328p caused significant delay in the responsiveness of the control loop. A teensy is far more suitable for this type of project.
01/25/2017 at 22:31 •
Time for propulsion measurements to define the values for the asymmetry of the thrust produced so that this can be factored into control software for stable flight.
Using my tablet as a Bluetooth controller to incrementally increase the % of throttle on the individual outputs
As well as a crude measuring stand setup and a camera recording the displayed values of thrust in grams.
This device was cheap and produced very poor results, after releasing applied force the value displayed would not return to 0 which showed this device was of true Chinese quality and hindered my 'science'
The graph showed a predictable result, as the coaxial rotor was twice the size and consisted of two rotors (2x2=4) the asymmetry was approximately 4 and more importantly it was apparently quite linear.
The testing also resulted in structural failure due to the lack of strong coaxial motor mount material. If only I had a workshop where I could machine aluminum..
Since balsa wood was easy to work with it was also easy to quickly make another mount which I used for testing software and concluded this version 1 of project T was not flight capable so my end objective for this version was not to get it to fly and that objective has been pushed to version 2 of project T which will require proper fabrication facilities.
01/25/2017 at 22:17 •
My least favourite part of any project - software
The software was long, messy and hard to follow for any life form other than myself.
There were also dozens of test code files I wrote for each of the sensors and functions of the flight computer since I wrote all of the software from scratch (inadvisable unless if you're trying to show off like I was).
Instead I've provided a slide from a presentation I gave on the project which shows some principle software.
The rest mostly consists of standard code for each of the input/output components including:
ESC output, current sensing input, Bluetooth output & input, state estimation.
I should also note that none of this software will be used in the second version of project T as I will be utilising a commercially available flight computer together with open source software which I will modify slightly to factor in the unique propulsion configuration and asymmetric control parameters.
01/25/2017 at 22:07 •
As repeatedly mentioned; due to a lack of facilities, time, budget, the fabrication process was extremely poor as was the structural quality.
There is a saying "TONY STARK WAS ABLE TO BUILD THIS IN A CAVE, WITH A BOX OF SCRAPS!!!"
Well I built this in my garden, with a box of scraps! too so...
Not bad, not bad at all Allen *taps one's self on the back*
01/25/2017 at 21:50 •
As the initial project was a demonstration of my abilities, coupled with my electronics background, I decided to design my own flight computer as well as my own flight software.
The flight computer consists of essential components for autonomous flight.
The MCU used is an Atmega328p, the Arduino bootloader is burnt to memory and Arduino IDE is used for programming via an SPI header.
Components include MPU9250, BMP280, HM-10, ultrasonic sensor, and current sensors
Eagle CAD was used for schematic and PCB layout as shown below
Due too previously stated limited facilities I was not able to use through hole plating and had to drill & solder vias manually which severely reduces the quality and design flexibility of the PCB, I recommend PCB design to be done well in advanced of deadlines & order cheap PCBs from china with cheap shipping postage.
Due to fake bluetooth module issues this PCB was not utilised in the Project T demonstrator
01/25/2017 at 19:29 •
The electronic systems consisting of electronic propulsion, power, and flight computer were designed simultaneously with the structure of the UAV.
Structural CAD for Project T is below
Bottom carbon fiber sheet CAD
Coaxial motor mount CAD
Finished CAD with all measurements calculated
01/25/2017 at 19:21 •
The most crucial step
The technology demonstrator has to be designed such that it can be built as quickly as possible with as little effort or complexity as possible while maintaining an affordable budget.
The system design is based on these parameters therefore it is not necessarily the optimal design for demonstration or technological progress.
My 1st design was based on not having enough money or any proper equipment and extremely limited time.
Therefore it was rushed, poorly built, and some mechanical & electronic components were not of the quality needed to make the 1st version a success.
A lot of knowledge & experience was gained however.
Suitable components have now been selected for a 2nd version of Project T but equipment is still lacking and therefore the project is pending suitable facilities for fabrication of the mechanical structure and airfoils.