Rotor count limit for gz_sim of VTOLS?

I am trying to build a gazebo (new, not classic) simulator for an octorotor vtol vehicle. However, it seems that there is a hard limit on the amount of total ESCs to 8, even though the total number of supported motors goes up to 12. The sim_gz parameter only goes up to a total count of 8, so I can’t add my aircraft’s pusher motor. When I try, I get the following error:

[Err] [] You tried to access index 8 of the Actuator velocity array which is of size 8

Does anyone have a suggested workaround for this? Is it just not possible to build an octorotor VTOL simulator in gazebo at the moment?


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Hi @bloodbornekart , could you share the gz VTOL octorotor model that you are trying to build and the associated PX4 airframe file please?

Hi Benja, thank you for your reply. I will send the files as soon as I can. However, I think that the problem isn’t in the SDF file because the motors are laid out properly into 8 seperate motor plugins (I tried grouping them into pairs to make it behave as a quadrotor, and it works fine). The airframe I am using is just the standard VTOL airframe file but with the motor number increased to 9.

The issue I am running into seems to be that the esc count parameter only goes up to 8, so I can’t add the pusher prop. It’s also seen in the QGroundControl actuator UI, where it will show 9 motors but only 8 available ESCs for assignment.

Did you solve the issue? Because I have the same one but with 8 motors for lift and 2 for cruise :smiley:

Thanks for your help!