Increase Iris Power - Gazebo

PX4 Autopilot
1

I want to make some changes to the IRIS model. (I use gazebo simulator)

  1. I want to increase the weight of the drone but still relatively maintain the performance in terms of speed, acceleration and thrust.
  • What changes are required to make?
  • there is any equation or guidelines for such changes?
  • I checked this topic (#110) but its for VTOL model and I dont know the value of some parameters such as Max Thrust [N] Max Applied Voltage [V].
  • I tried to make some changes but without success, the drone loses control.
  1. In addition, I want to improve the performance of the drone in terms of speed, acceleration and thrust.
  • I tried to make a number of changes to the parameter in the SDF file for each motor.

These are the default parameters:

    <plugin name='front_right_motor_model' filename='libgazebo_motor_model.so'>
      <robotNamespace/>
      <jointName>rotor_0_joint</jointName>
      <linkName>rotor_0</linkName>
      <turningDirection>ccw</turningDirection>
      <timeConstantUp>0.0125</timeConstantUp>
      <timeConstantDown>0.025</timeConstantDown>
      <maxRotVelocity>1100</maxRotVelocity>
      <motorConstant>5.84e-06</motorConstant>
      <momentConstant>0.06</momentConstant>
      <commandSubTopic>/gazebo/command/motor_speed</commandSubTopic>
      <motorNumber>0</motorNumber>
      <rotorDragCoefficient>0.000175</rotorDragCoefficient>
      <rollingMomentCoefficient>1e-06</rollingMomentCoefficient>
      <motorSpeedPubTopic>/motor_speed/0</motorSpeedPubTopic>
      <rotorVelocitySlowdownSim>10</rotorVelocitySlowdownSim>
    </plugin>

And again after many failed attempts I posted this Topic.

Will making changes only in the SDF file give the solution?

I assume itā€™s easy to modify but Iā€™ve reached a dead end.

2

The gazebo motor plugin lacks organized documentations in my opinion,
but my experience tells that the ā€œmotorConstantā€ increases the thrusts of each motor.

You would likely have to retune the PID gains though. If you are not going to replace the PID controller in the firmware to other structure of controller, the performance of the drone would be mostly dependent on the PID gains.

-Kangmin

1 Like
3

Hi @kangmin7, thanks for your reply.

I changed the ā€˜motorConstantā€™ parameter in the SDF file but the max velocity and acceleration of the drone are remained the same.

however I noticed one change in the Qgroundcontrol. the ā€˜Throttleā€™ has changed.
with the original ā€˜motorConstantā€™ value: the Throttle was 100%
with bigger ā€˜motorConstantā€™ value: the Throttle was 45%

So I assume there is another limitation somewhere else that limit the drone.
Do you have any suggestions?

thanks.

4

Could you tell what the maximum velocity was?

The QGC parameter could be limiting the maximum velocity,
so you may have to change that too

5

You can check this issue on github, There is an explanation of how to increase maximum velocity of the iris drone.

Iftach.

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