Servers by jDrones

Less throw in acro then in manual flight

(Christian) #1


I’m trying to find why i get less throw on the servos in acro mode then i have in manual mode.
I would like to fly with Acro and still have the same feeling like i do in manual mode.

What parameter should i change?


(Hunt0r) #2

Have you started by reading the documentation about ACRO mode? In it, you’ll find that several key parameters determine the ACRO behavior, and searching for ACRO parameters will find the rest…

(Christian) #3

Yes i have looked in the documents but i can’t still figure out what params to change to get more throw on the ailerons.
I find how to get faster response with less stick input but i’m not intrested in that.
I just wanna fly like normal but have the pixhawk compensating for wind.

(Hunt0r) #4

It seems either I don’t understand your goal, or you don’t understand plane control. Probably there’s some misscommunication, let’s figure that out.

Roll rate is caused by aileron deflection.[1] So therefore “more throw on the ailerons” is equivalent to “faster response with less stick input.” Or am I mistaken?

Perhaps you could be more specific in describing what behavior(s) you hope the plane to have while flying in various winds?

[1] This statement omits some unnecessary complexity…

(Christian) #5

Okey no problem, i’ll try to explain more in detail. :slight_smile:

In Manual mode my Ailerons have about 20mm throw at full stick input.
As soon as i switch from Manual mode to Acro mode (keeping full stick input) i get less throw, about 10mm in both directions. But my goal is to keep the 20mm throw at 100% stick input even in acro mode.
I have the 10mm throw at about ~25% stick input and the 75% that is left of the stick input is just a deadzone.

Even if i try to increase the Roll Rate i don’t get desired throw (20mm) just faster response on the stick inputs.
It’s like the Endpoint of the servos decrease as soon as i switch to acro mode.

Well i like the acro mode more then lets say stabilized that will keep the plane level as soon as i drop the sticks.

(Hunt0r) #6

Ah! Thank you, I think I understand the issue now.

ACRO mode controls the plane’s roll-rate, via the roll-rate PID controller. The ground-test that you describe isn’t necessarily a fair test of ACRO’s performance: if you give roll-stick but the plane doesn’t sense that it rolls accordingly (because it’s not actually flying) then it has logic to decide how to resolve that situation. Evidently that logic has some (at least temporary) limit at less than 20mm throw, which is why you don’t see full-deflection of the ailerons.

That “logic” (the PID controller + safety limits + other parameters) isn’t simple, but it IS fully configurable, if you are dedicated to learning how.

But from your description of your desired behavior, it sounds like you want aggressive control of the plane when using the sticks, and for it to stabilize itself when you release the sticks. I think ACRO is the right mode for you. Would you try temporarily ignoring your ground-test and flying ACRO the way it’s designed? Configure it through it’s standard parameters, and see if you can get your desired behavior.

Your plane has some aerodynamic limits on how aggressive it can fly… but if you can’t configure ACRO to fly as aggressively as MANUAL, then post back here (maybe also with DataFlash logs comparing MANUAL and ACRO flight?) and I (or others) can probably point you towards other parameter changes.

(Christian) #7


It sound like i have to increase P or I on the Roll to get same feeling when in Manual mode. So i get the airplane to roll in Acro mode like it does in Manual mode.
I’ll get back in a few month maybe weeks when i get to fly again :stuck_out_tongue: