Where To Put The Flight Control Software - UAV or Ground?

[FirmamentFX]

As far as I can see there are 2 ways of building a flight control system for a UAV:

1 - The software and processor is in the aircraft:
All that is sent from the ground is a series of control signals to activate functions on the aircraft. From the aircraft the ground station receives sensor data (GPS, Inertial Data, microswitch data, positional sensors etc.)

Advantages
- Autopilot can be used from inside the aircraft, therefore the aircraft can go beyond radio range. In the even of radio signal loss, it can be programmed to return to an area where radio signal can be picked up again.

Disadvantages
- Complicated data transfer mechanism. The control signals sent to the aircraft are then processed, turned into control surface / switch commands, which are then activated. Sensors then work out if these commands have been carried out and relay the data back to the ground.
- Complex and potentially heavy system in the aircraft. A full computer would be necessary to process commands.


2 - The software is on the ground:

Advantages
- There is no need for a massively complicated system in the aircraft. Data can be processed using a high powered laptop or similar on the ground.
- Simplification of data transfer: there would be no need for complicated transfer systems.

Disadvantages
- The UAV is limited to radio range. Autopilot could not operate out of range because the autopilot is on the ground.


What do you think?

Martin

[sergey123]

Definitely option number one. Complete autopilot system on aircraft.
1) Probability of losing aircraft because communications delays, radio noise and etc will so high that it will be much more fun and less expensive to crash it manually in on local air club field.
2) CPU on aircraft: almost any real CPU have enough power to do all required processing and stabilize, direct aircraft on all submitted way points. Extra power may be required only for submitting to ground station high compressed video stream (live mpeg4) in low bandwidth channel. Ideally communications between airframe and ground station not needed al all. You can setup waypoint on the ground after that switch autopilot on and it will auto takeoff fly around, make pictures and etc and land by itself.
3) By having complete autopilot system on aircraft you will have ability of using different type of communications with it even if it been lost. Ceil phone, satellite phone and etc. Just call aircraft and ask question where are you? You do not need any bandwidth for doing so. Or correct direction on the fly? Connect, new waypoint, commit, and disconnect – all in a sec.
4) Emergency landing, return to base – easy. Something wrong with any sensors or something – return to base, turn of engine, open parachute..

5) :)))) just more fun …………

[FirmamentFX]

I see what you're saying.

On the ground you would want:
Displays - Primary Flight Display, Navigation Display, ECAM (Engine/Warning Displays, System Display), MCDU display.
Inputs - Joystick, Thrust Levers, Various Panels (ie a custom keypad or keyboard with overlay).
Video Link - This doesn't even need to go through the processing system. Complete Tx/Rx systems can be bought very cheaply (http://www.digitaltelemetry.co.uk).

Assuming all of the above, the data transfer:

From GROUND to AIR: Command Inputs (joystick/thrust/switches)
From AIR to GROUND: Display Data (actual graphics can be generated on the ground computer), and Video Link (on a separate system).

You could get all silly and have "force feedback" to the joystick, but that's going a bit overboard :))

Actually, when it's typed out in its basic form it looks simpler than I had imagined!

I would also integrate a "get you back down" system, which would be a regular R/C transmitter which commands a futaba (or similar) receiver in the UAV with basic controls (pitch, roll, yaw, thrust, flaps & slats, landing gear), The receiver in the aircraft is linked on a separate elec and radio system to the servos.

M

[sergey123]

For sure everything what you saying about ground station is great just an addition to onboard autopilot to see plane position and parameters, change direction, change waypoint, see real video and etc – all these just great but it is a second step after having flying on its own plane :) .... its just my thoughts …..

In any case GOOD LUCk !!!

[TheBobby]

Autopilot MUST be in the aircraft. Imagine that u loose radio transmission for 1 sec, even if you are in the range. What will hapen ?
I'm fully agree with Sergey123, this have to be embedded. Ground software is only for displaing data (GPS position, atitude, altitude, video, ....)
You can manage way points on the ground and send it to the aircraft, but the stabilisation and the autopilot have to be onboard !

Good luck for your project.

[typicalaimster]

I'd suggest putting the autopilot in the plane.. Loss of Link is a big factor as mentioned above. Let the autopilot computer onboard the plane do it's job. Return to home can be one of the simple jobs.

There may be times when a flight control system needs to remain on the ground. For example a joystick control software that sends the control commands up to the plane via RS-232.