Saturday, 7 February 2015

Multicopter. Development phases. (Part 8)

In this blog I'm going to look at the possible routes that multicopter development can go. Thus far I've identified 3 phases. My goal is to develop a phase 3 multicopter as described below. But the technology is changing rapidly so there may soon be still more phases.

Phase 1.

  • A remote controlled model is produced. In my case the airframe is produced on the 3D printer. 
  • A cheap and simple flight control is needed to maintain stability. 
  • The craft has no autonomous features - it is under manual control, by the pilot on the ground, all the time.

Phase 2. Onboard cameras/video are added. Here we enter the realm of the consumer drone products that are currently in the shops. Certain parts of industry are going to considerable lengths to de-skill model flying and turn the camera carrying drone into a consumer gadget.
These feature:

  • A flight control system of greater complexity. 
  • A video transmitter streams video back to the operator from the on-board camera. 
  • The control system allows him to steer the drone and set up various shots.  

Phase 3, the third level of increasing complexity, is still only within the advanced DIY or professional range of operators. Here a still more complex flight control system is needed. The machine is capable of  autonomous flight but a variety of direct control modes, intended to make operation easier are possible.
  • Flight planning is carried out on a ground station, usually a laptop. The operator plans a route for the drone and uploads it as a set of waypoints.
  • The drone has a long range two way data link and parameters such as speed, position, altitude and battery condition are streamed back to the ground station.
  • Additional sensors such as 'Optical Flow' are used to improve automatic positioning. This sensor uses a downwards looking video camera which analyses the machine's movement over the ground in a similar way to an optical mouse. This gives a position and instantaneous speed far superior to GPS. Useful for indoor operation and applications that require great motion accuracy.
  • Operation well beyond line of sight range is possible, a radio modem passes commands from a ground station laptop to the drone.
  • Automatic return to home. This uses GPS so that the onboard flight controller can steer back to the take-off point. 
  • Possibly auto-land so that an unskilled pilot can get the drone (and an expensive camera) back on the ground safely. 
  • Sometimes, 'Follow-me' where the operator carries a GPS receiver which tells the drone where the operator is. The drone will turn towards him, video him and follow him. 

Phase 4 and beyond are science fiction. 
  • A large drone with long flight duration, probably using an internal combustion engine to top off the battery system.
  • The machine is big enough to carry a man but it is largely autonomous. 
  • Multiple motors are used to give safety critical redundancy. 
  • Flying is de-skilled to the point of setting the destination in the navigator and letting the machine get on with it. 
  • You can summon the drone, automatically, to pick you up from the pub.
  • It's a commercial product costing about the same as a Tesla automobile.
Phase 4 is the fun part and don't expect to have to wait long. I've already seen an ultralight aircraft take off with one man onboard. It climbed to altitude automatically, the man took to his parachute and the aircraft landed itself. So here's something to be getting on with.


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