Multirotors (2010 - 2012)
Interested in electrical propulsion systems, I developed a couple of generations of quadcopter and tricopter platforms, these acted as my first introduction into the field of drones. Built before the drone hype cycle peak, there was little information around at the time regarding flight controllers, component selection and propulsion choices. I also used drones as the basis of a few Blender 3D modelling and animation doodles.
- General Prototyping
Left/below: The final tricopter version and a render of one of the earlier tricopter designs.
First generation quadcopter
Back in 2010 there were no direct build tutorials avaiable for building drones, let alone off-the-shelf products or kits; the only information avaiable was in short blog posts, comment sections and discussion forums. The main guidance used for the first generation of quadcopter was a 2010 DiyDrones blog post, with some part specifications as a starting point. The blog post used a ArduIMU V2, however due to price constraints I used the ArduIMU V1, a small attitude and heading reference system (AHRS) comprised of an ATMEGA328 microcontroller and a sub-boards on each axis, each with a accelerometer/gyroscope chip...
I don't have any photos of the first generation of quadcopter, but there's a couple of old youtube videos that I uploaded after a couple of years of having the quadcopter. Once new flight controllers were released, I updated the hardware to make PID tuning easier and to make the quadcopter smoother during flight, however due to the magnitude of on-board vibrations a new multicopter platform would have been the best route for better flight characteristics.
At the time I was also experimenting with Blender modelling and rendering, so I developed another custom quadcopter frame in AutoCAD, imported the DXFs into Blender and 'virtually assembled' the drone. I ended up laser cutting the quadcopter frame out of Delrin, however no photos were taken at the time and I moved onto the tricopter variant without flying the new quadcopter frame.
The quadcopter lacked accuracy when flying and felt too robotic for my liking, causing me to turn my attention to tricopters. Quadcopters use two sets of counterrotating propellers to provide lift, then vary the speed of each set in order to turn through the principle of conservation of angular momentum. However, tricopters only have three blades, so it's not possible to rotate through the same principles. Instead tricopters incorporate a servo mounted to the tail, rotating the rear motor and alternating the direction of thrust, causing the tricopter to turn. Consequently, the tricopter flies similarly to a speedboat, contrasted to the bulldozer robotic nature of the quadcopter.
The original iterations had little adaptability, however the final derivative comprised of a sleeker design and space for additional equipment, as well as electrical changes to accommodate an on-board camera. The flight time was roughly 15-20 minutes, depending upon flying style and payload. Again, a custom design was drawn up in AutoCAD and lasercut; I played around with the design in Blender whilst designing the tricopter, rendering a quick concept using Blender's cycles render engine. Given that the technology was advancing very rapidly at that stage of the hype-cycle, a different flight controller from the quadcopter was used, however the flight controller and Electronic Speed Controllers (ESCs) were flashed with updated firmware to increase the stability of the tricopter whilst flying, by allowing for a higher sensor refresh rate, and larger heatsinks were added to deal with additional current draw for greater tricopter speeds.
Over the years there were multiple upgrades, notably an on-board camera allowing for simultaneous HD (1080p) recording and live output for transmission to a user headset for First Person Viewing (FPV). There were other minor hardware changes, including switching over to carbon fiber propellers, increasing durability and reducing vibrations through the frame that would disrupt both the Inertial Measurement Unit (IMU) sensors and video footage.