TECS With QuadPlane

Hello everyone,

I’ve encountered something weird with the way that TECS works on quad planes.
The output for throttle, which is received from TECS, is different than the output to the tilted motors.
It looks as if there’s a slew rate cap (which I wasn’t able to locate) that does not match with the throttle’s change rate.

I’m attaching a log (firstflight) that was created by running RF9 with the model found here.
The parameters used are the ones in the folder, but I’ve changed the servo function for servo9 to be throttle, with the min, max, and trim values adjusted so that the logs could easily show the throttle demand from TECS alongside the output for the tilted motors (graph RCOU.C5 RCOU.C6 RCOU.C9). I also changed the relevant flight modes to be QHOVER and FBWB.

The airspeed TECS requests and the one achieved are different towards the end of the FBWB phase where my throttle stick is at the bottom.

I ran another flight, and I’m attaching the second log as well (secondflight).
Note: please disregard the timestamp on the log, my clock was acting strange. The secondflight log is the one for the second test.

For the second test I changed the maximum and minimum speed to be 35 and 20 compared to 28 and 10 respectively (m/s).

I’d like to know why does this happen and whether it’s intentional or not. Any help would be appreciated.

Logs: Link
I’m sorry about the inconvenience of the link, it wouldn’t let me upload the compressed logs.

Thank you,

I have an update regarding this.

I’ve dug through the code and found out that before passing throttle to the tilt servos it runs an adjustment function which takes into account battery and Q_M throttle expo and spin parameters.

I can understand why these are taken into account but why are these parameters not set for standard planes? to get to the Q_M parameters Q_ENABLE must be set, which means we’re running a quadplane.

I can’t find any equivalent “regular plane” expo parameters. Assuming that there’s an equivalent throttle adjustment for planes. But then again the throttle is used for the propellers directly. Even throttle left and throttle right appear to be set using the DT and throttle only.

I’m having trouble understanding how this works for planes, but I guess this subject deviates from the title.

Edit: I was told on Discord that there’s no need for throttle adjustments for forward flight.