What do FPV flight controllers do?

[pedz]

I have a DJI Avata. I mention this because I’m not 100% sure if it behaves like other FPV drones. I can’t find a flight simulator that works with my controller so I’m just putting the Avata into manual mode and flying (and crashing) it. I’m slowly getting the hang of it but I’m trying to make sense of what I’m seeing and doing.

I’ve flown RC planes and they generally have a dihedral and are balanced so more or less if you do nothing, the plane is stable. And, with a drone like a DJI Mavic, if you let go of the sticks, the drone will stop and be stationary in the air. But the Avata in manual mode seems different from both of these. Once it starts tilting to the left, for example, it will stay tilted at the same angle until the pilot puts in an input to change that angle. Which confuses me. If that is the case, then what is the flight controller doing? Or… am I misinterpreting what I’m seeing?

 

[Kilrah]

Manual on Avata, equivalent to "Acro" on other systems intentionally removes most of the "helpers". Your sticks become an angular speed command for each relevant axis. So stick centered = do not rotate around that axis i.e. keep doing what you're doing, and throttle is direct.

The FC still controls motor speeds in order to obey those angular speed commands, since it's entirely impossible to directly control each motor manually to achieve it.

I’ve flown RC planes and they generally have a dihedral and are balanced so more or less if you do nothing, the plane is stable.

It's somewhat like a competition aerobatics plane in comparison to a trainer, no dihedral, symmetric wings, and adjusted/balanced/compensated so that without input it as much as possible stays on its course whatever the situation instead of trying to bring itself back to level, which is unwanted if you're trying to be in control to do something precise. Of course it does mean you have to be in control, it won't do anything you don't command.

 

[rktman]

In manual mode the FC is responsible for controlling the thrust of the 4 motors so that what you command is carried out (i.e. roll left stick the FC will increase the speed of the two right motors and decreases the two left), and hold aircraft attitude when there is no command input.

 

[Deleted member 10023]

In manual mode the FC is responsible for controlling the thrust of the 4 motors so that what you command is carried out (i.e. roll left stick the FC will increase the speed of the two right motors and decreases the two left), and hold aircraft attitude when there is no command input.

I have three non-DJI FPV drones: cinelog 20, nazgul evoque f5, and a custom one I built. None hold altitude when I stop stick inputs. Depending on the the last thrust input, the drone will drop from the sky or climb. Maybe if you have one with a barometer and gps you can program it like a DJI drone to hold altitude. For me, maintaining altitude and position is accomplished by balancing stick inputs.

Now the Avata in sport and normal will hold altitude once stick inputs are halted. In manual mode (acro) it will behave like a typical FPV drone requiring pilot input for all control.

 

[Deleted member 10023]

I have a DJI Avata. I mention this because I’m not 100% sure if it behaves like other FPV drones. I can’t find a flight simulator that works with my controller so I’m just putting the Avata into manual mode and flying (and crashing) it. I’m slowly getting the hang of it but I’m trying to make sense of what I’m seeing and doing.

I’ve flown RC planes and they generally have a dihedral and are balanced so more or less if you do nothing, the plane is stable. And, with a drone like a DJI Mavic, if you let go of the sticks, the drone will stop and be stationary in the air. But the Avata in manual mode seems different from both of these. Once it starts tilting to the left, for example, it will stay tilted at the same angle until the pilot puts in an input to change that angle. Which confuses me. If that is the case, then what is the flight controller doing? Or… am I misinterpreting what I’m seeing?

Echoing what was stated above, the FC in manual mode is adjusting motor speeds to achieve the angular state of the drone and desired thrust. It is interesting.

The Avata is a great drone but not the best for a beginner to learn manual flying on. With a typical FPV drone, you have multiple states you can fly the drone in working up to full manual (acro). Angular mode keeps the drone relatively level when flying. Horizon mode levels the drone when stick inputs are halted but also allows you to aggressively flip and roll the drone 360 degree. Acro mode the drone stays in the same position relative to the last stick input. The Avata in normal and sport mode does not provide varying levels of control just a speed bump.

 

[rktman]

Back to the discussion, holding attitude is the most important thing the FC does in manual flight. And it is very actively monitoring the gyro and constantly controlling individual motor thrust to hold the pitch and roll angle when there's no stick input.

Without this the aircraft would be tumbling all over the place.

 

[GFields]

Stay on topic and NO more personal attacks or this thread WILL be closed!