Servers by jDrones

Setting servo limits, and airspeed

fly-for-effect
(James Miller) #1

When setting up Arduplane, where should I set up the desired surface travel? In arduplane, or in my transmitter? If, for example, I need 10mm elevon “up” travel, should I set this up in my transmitter as usual, and set maximum safe servo travel in arduplane parameters, or the other way around?

As well, Airspeed alters the needed travel. It seems Arduplane must vary the amount of control surface movement, and if so, based on Airspeed? and/or deviation from desired position/rate §?
In another controller I used for a long time, I’d set surface travel in my transmitter, and the controller would vary the amount of surface travel a lot- sometimes to the limits of servo travel.
On a bungee or tow line launch, surface travel must be greater during the first few seconds to keep the bird under control. Does this happen depending on airspeed ? GPS speed?
Thanks all. New (ish) here.

(Peter Hall) #2

you control the throws with the servo parameters

http://ardupilot.org/plane/docs/servo-functions.html#controlling-servo-throw-trim-and-reversal

Deflections are scaled with estimated airspeed, this is based on the gps speed if you don’t have a airspeed sensor

(Mike D) #3

You want to set up your surface travel ranges and trims in Mission Planner. This is where you set the absolute minimum and maximum deflections for each servo.

I think that adjusting the SCALING_SPEED param will adjust how to reduce your throws.

I know of some people who take off in manual and engage autopilot modes once the plane is in the air, which is the easiest method to start with. You could look into doing automatic takeoffs, there are a lot of parameters that you should adjust if using a catapult launch with an auto takeoff. http://ardupilot.org/plane/docs/takeoff-mode.html

(James Miller) #4

“Deflections are scaled with estimated airspeed, this is based on the gps speed if you don’t have a airspeed sensor”
Been trying to discover this for quite some months. Thanks very much.
Still the question of how much deflection and —where does it start? Do I set up the max safe throws and expect the FC to reduce them at higher speed? --using the amount that achieves the desired position/rate?

(James Miller) #5

Thanks. I’ll set up the safe maximum travels, and fiddle with the scaling parameter to see what it does.

(Peter Hall) #6

yeah, set the max throws and leave it to the flight controller, it will typically fly sort of spongy to start with, a auto-tune will get it flying nice.