I was thinking of designing and building my own autopilot for a project.
I do have a APM 2.6 and its a brilliant piece of hardware but a little too complicated for what I have in mind.
What I need is a autopilot that is basicaly a 3 axis flight stabilizer, I have no need to fly waypoints autonomously but it must have a auto takeoff, auto landing function eg. at takeoff it automatically assumes a given speed an climb attitude to a programmed altitude and landing it assumes a landing profile and autonomously land.
"Return to controller" function eg. The uav returns to the controller not a fixed gps location meaning the operator are free to move around and the uav will return to him.
The primary flight mode will be similar to FBWA it should hold its altitude, heading and level the wings and changing direction you simply steer it to a new heading or altitude then leave the controls.
It should also have a "circle" function eg. when selected the drone starts to circle an area and keeps doing so until a new function is given.
Auto throttle eg. the speed of the uav will never go lower than stall speed and it will maintain a specified cruising speed even in head winds.
Full telemetry communication at 10 km range without the need for directional antennas.
Video for 10 km range and have a integrated OSD.
Be able to stabilize brushless motors for a camera gimble.
The autopilot should basically do all the processing work eg. no need for a large complicated ground station like a laptop. The ground station is basically the controller, telemetry radio and video receiver/ screen all in one. The initial setup can be done with a computer.
Is something like this possible? If so where do I start? Think Hubsan spyhawk but with more fuctions.
Replies
I have one comment. You said that you want the UAV to maintain a constant cruise speed even in a headwind.
This is a concept that many, many ground based pilots have trouble to grasp but can have drastic consequences if not properly understood.
To the aircraft in flight, there is no headwind, tailwind, crosswind. Its reference is the air mass it is moving within.
The ground based pilot however, is anchored to the ground and so does feel the air mass moving past. (wind)
The aircraft travelling at an airspeed of 100 mph, can turn and travel in any direction and will always have an airspeed of 100 mph if all things are done in a coordinated fashion.
The mistake rc pilots make is that watching the aircraft from the ground, we see its airspeed modified by the wind speed, and see the resulting groundspeed.
To many rc planes have been lost due to the aircraft turning downwind, and as its groundspeed increases the pilot throttles back, bringing the airspeed back to its stall speed.
An extreme example of this is if the wind speed was 100 mph, the aircraft travelling up wind at an airspeed of 100mph, has a groundspeed of 0 mph.
As it turns downwind, it picks up groundspeed until its going 200 mph across the ground.
If you mean that you want a steady groundspeed, then you will have to adjust its airspeed to achieve that, and this is where the stall speed override will come into play when the UAV is travelling downwind.