Main 8 Port, no PWM Signal

PX4 Autopilot VTOL 🚁
1

Hey,
I am currently setting up a new VTOL.
It is very similar to the E-Flight Convergence but can also tilt the rear motor in flight direction. Therefor I just use the Convergence Airframe definition and added a slightly changed mixer definition into the /etc/mixers directory on the Pixhawk. I am using the CUAV V5 Nano flight controller. It has 8 PWM outputs on the main-port, but no aux-port.
The only thing I canged with the mixer file is to replace the “Null Mixer” ( Z: ) with the mixer for my rear motor.

M: 1
S: 1 4 0 -20000 10000 -10000 10000

The mixing for the rear motor works fine, but my left elevon does not move (output 8).
Also in the attached logfile there is no Output 7 logged. (Actuator Outputs Main).

bokeh_plot%20(8)
bokeh_plot%20(8)1260×504 61.7 KB

Don’t pay to much attention to the logfile, the PID’s are not tuned yet. Any tips in that regard are appreciated tough.

I also have another question regarding the Yaw Check Bit, what does that mean exactly?

The whole mixer file:

Summary

Adapted E-flite Convergence Tricopter Y-Configuration Mixer

Motors

R: 3y 10000 10000 10000 0

Tilt mechanism servo mixer

#Center up:2000 down:1000
M: 1
S: 1 4 0 -20000 10000 -10000 10000

#RIGHT up:2000 down:1000
M: 2
S: 1 4 0 -20000 10000 -10000 10000
S: 0 2 5000 5000 0 -10000 10000

#LEFT up:1000 down:2000
M: 2
S: 1 4 0 20000 -10000 -10000 10000
S: 0 2 5000 5000 0 -10000 10000

#Elevon mixers

M: 2
S: 1 0 7500 7500 0 -10000 10000
S: 1 1 8000 8000 0 -10000 10000

M: 2
S: 1 0 7500 7500 0 -10000 10000
S: 1 1 -8000 -8000 0 -10000 10000

2

After a lot of frustration i got the mixer working correctly by just changing the order.
I moved the two elevon-mixer up, right after the motors and moved the three tilt servo outputs down. I did not change anything other than that and everything moves as expected. So there must be something wrong in the way px4 handels mixer files.

3

Hey Thomas. Glad we could get it to work!

if this is reproducible consider opening an issue on github or perpaphs if it’s intended we should add it to the documentation.