[Bug] Constant force on spacecraft after make

[joris997]

Describe the bug

During initial operation, the /fmu/out/actuator_motors should publish actuation signals of all actuators of value 0.0 and the robot should remain static. This is not what happens. Instead, a constant force is being exerted on the platform.

This bug seems to be unique to Gazebo Garden.
I haven't tested this, but @Pedro-Roque told me this does not happen in the old Gazebo (see readme install instructions of this repo)

To Reproduce

1. source ros and microros
2. start the microros service ros2 run micro_ros_agent micro_ros_agent udp4 --port 8888
3. make PX4-Space-Systems with the 2D space platform make px4_sitl gz_spacecraft_2d
4. observe the movement

Other than that, you can additionally use QGroundControl and arm the robot. In position-mode, the robot behaves as expected and moves to the origin. In acro-mode, the robot is also subjected to this constant force.

Expected behavior

The robot remains static

Screenshot / Media

Arming the robot, enabling position mode, these are the /fmu/out/actuator_motors output

Armin the robot, acro-mode, these are the /fmu/out/actuator_motors output

Software Version

PX4-Space-Systems with Gazebo Garden with the DISCOWER px4_msgs and the DISCOWER gz-sim

Vehicle type

spacecraft_2d which grabs kth_freeflyer

Additional context (what I tried)

I created a custom kth_freeflyer model which has its maximum actuation set to 0.0. In this scenario, after startup, the robot does not move at all, indicating that there is something wrong on our end, not necessarily on Gazebo or the world file.

[Pedro-Roque]

I could not reproduce your problem @joris997 . I do observe the force but the vehicle motion seems decoupled from actuator_outputs. In my case these are constantly zero. I'll check further on gazebo.

[Pedro-Roque]

This issue is now fixed: there was a problem when targetDutyCycle was zero, that it would equal the beginning of the duty cycle, and therefore it would fire all thrusters.

This was fixed on the last commit to gazebosim/gz-sim#2431