Mixing RC Aux1 and Yaw channel in Dynamic control allocation

PX4 Autopilot Multicopter 🛸
1

I am building a multirotor that would hover at a set altitude and move like a tank (skid steer) with two motors that pull it forward and control Yaw using differential thrust.

In the previous version of PX4, I made a custom mixer file to mix Aux 1 (desired forwarding throttle) and yaw using the mixer lines below but I have no idea how I do it with the new system. The original system was limited to manual control of forward thrust and I would like the controller to use the forward thrust when doing position hold and waypoint following instead of pitching forward to move forward.

At the moment I have yaw being sent to the motors by setting their position and orientation to forward with SYS_CTRL_ALLOC = 1, CA_airframe = custom and that is really slick but how do I mix in the desired forward thrust?

Any assistance would be appreciated.

Example of the legacy style mixer file
R: 4x

5: right
M: 2
S: 0 2 -10000 -10000 0 -10000 10000
S: 3 5 10000 10000 0 -10000 10000

6: left
M: 2
S: 0 2 10000 10000 0 -10000 10000
S: 3 5 10000 10000 0 -10000 10000

Current actuator tab

image
image1399×870 113 KB

2

In your current configuration, the control allocation module is already able to use the forward motor to track forward thrust setpoints. However the control pipeline of the generic multirotor can’t exploit this functionality and all desired forward acceleration are converted to non-zero pitch references.

3

Thank you, that confirms I need a custom controller to really take advantage of the new control allocation module for this configuration. I will go digging through the example of the Onmicopter to see what they did there.

Link to Omnicopter