What's surprising is that drones didn't require any groundbreaking new technology to emerge.
So, why did they take so long to become mainstream?
What's changed is economics. Drones were initially incredibly expensive, but the price of electronics, motors, and batteries have come down and become smaller and lighter over time. Only fairly recently have those prices fallen to the point where normal people could afford them, and well-funded people could afford large quantities of them.
Biggest reasons are a) availability of ARM based SOCs that have some pretty good processing b) Lithium batteries
Back in 2000s, lithium batteries were coming out, but werent as safe. Being into the RC world, you would see plenty of battery fires. If you wanted to be safe, you generally went with NiMH batteries, which were heavier.
In terms of aerodynamic efficiency, its much more efficient to move large amount of air slowly rather than small amount of air fast, and the efficiency gains from this are higher than efficiency gains from running multiple small motors rather than one large motor.
Additionally, there were some notional autopilots microcontrollers, but they weren't really that good in terms of being able to do accurate AtoD sampling.
Thats why RC helicotpers were used heavily as "drones" back in the day, with the bigger ones running on gas engines that could support heavier payloads that included a stabilizer autopilots. With a helicopter, you also used to have a stabilizing flybar that could give you stability in place of flight controller with a gyro.
Once Lithium batteries became safer, cheaper, and higher energy density, and microcontrollers like STM32 with Cortex chips came out that got some A2D samplers into the GHZ range, drones became more viable due to mechanical simplicity (controlling motors rather than a complicated swash plate linkage), especially since the body can be flat carbon fiber pieces that are very cheap to make and are very strong and light.
Brushless DC motors, strong injection molded plastics, PID control algorithms, rechargeable battery energy density, fast CPUs, communication protocols, maybe geolocation via GPS. Without any one of these (and probably 5 or 6 more) quadcopters wouldn't be feasible.
Gas powered remote control flight has certainly been available for a long time, however commercial GPS for navigation and high bandwidth wireless connections and cameras for video feed certainly weren't available. These RC planes used to be a novelty, you'd fly within visual line of sight only. Now you can bomb targets 1000 km away with them with decent accuracy as shown in Ukraine - Russia war.
- Boom of small & lightweight HD cameras, your GoPros and the like.
- Proliferation of video editing tools – and more importantly skills – as internet-based video platforms grew more popular.
- Quadcopters (and other RC aircraft) became cheaper and more stable with each passing year.
Each of these democratised aerial photography – something you could only do if you hired an aircraft and souped-up camera to go with it, an insane expense. Then like any other technology, the more people use it, the more uses we find for it.
The smartphone revolution was a gamechanger for the price and availability of GPS receivers as well as accelerometer/gyro systems.
Especially in the context of recon and military deployments.
So they’ve captured more of a mindshare I guess.
https://en.wikipedia.org/wiki/Second_Nagorno-Karabakh_War#Dr...
In terms of hardware, a small drone is essentially a smartphone connected to motors, right? The autopilot needs a bunch of sensors to estimate its position, and it turns out that many of them (e.g. IMU, GPS) are part of smartphones.
With the mass production of the smartphones, those components have become infinitely cheaper, making it possible for a student to build a drone at home. If you look at open source autopilots like Ardupilot, it seems to correspond to the era of smartphones, I think.
- Cheap, highly accurate, low current draw accelerometers.
- Cheap, low current draw and miniaturized GPS modules.
- Cheap, low current draw wi-fi radios with excellent range.
- Cheap, low current draw, high resolution, high quality cameras.
All of these are recent advancements.
tl;dr: All of the needed ingredients became cheap and low current draw.
batteries, compact and capable of high load
power circuits (both in power and the size)
demand
compact electric engines capable of high torque with high load for the long enough time