Advice on implementing variable pitch propeller in gazebo for px4_sitl

PX4 Autopilot
1

Hi

I’m working on drone which uses an additional variable pitch propeller on the back, controlled via some ROS topic.

This propeller allows forwards and backwards movement without altering the drones pitch.

I am attempting to create my drone in the px4_sitl, but am unsure on the best way to create this variable pitch propeller.

The propeller spins at a constant RPM, with the pitch being changed allowing a variable velocity.

My current approach is to create a new propeller that is similar to the typical quadrotor propellers, using the libgazebo_motor_model.so plugin.

I am extending the plugin to allow the ROS topic to vary the motorConstant parameter and turningDirection, allowing forwards and backwards movement.

I have reduced the timeConstants, this I think will work but it’s not ideal- is there a better way to implement a ‘real’ variable pitch, rather than essentially just switching the motor in and out of reverse quickly?

Thanks for any input

2

Just in case anyone comes across this in the future, I implemented my variable pitch propeller by
creating a new plugin, a modified version of motor_model plugin to subscribe to a ROS topic obtaining a pitch value between -1 and 1.

Where the force is calculated in motor_model.cpp (force * scalar) I then multiplied by my pitch value, this works as I’d hoped.

3

@Uplinkc60 Would be awesome if you could contribute your changes to https://github.com/PX4/sitl_gazebo