Clarification on Each Dimension's Meaning for ActionType.VEL about gym-pybullet-drones

[JacopoPan]

Hi @input-0313

yes, you are correct, the first 3 components of the 4D action space in ActionType.VEL are interpreted as a direction in the 3D space, normalized to a unit vector, and then multiplied by the 4th component, interpreted as the desired velocity magnitude.

Of course, as you noted and if you prefer, you can modify this simply by re-implementing method _preprocessAction (part of the reason for doing this was simply to preserve the action space dimension across aviaries and not not change network architectures between learning example).

[input-0313]

@JacopoPan Hello
Thanks for your previous reply. I'm implementing horizontal flight with the CF2X drone model, where the URDF file specifies a maximum flight speed of 30km/h. I've set the action space's xyz velocity thresholds at 8m/s before passing them into the controller, based on the speed unit in BaseRLAviary's "self.SPEED_LIMIT".

However, the actual drone speeds seem substantially lower than these set points. Does PyBullet have an intrinsic speed limit, or are there constraints on the velocities fed into the controller? Additionally, the drone occasionally flips or exhibits instability—might this be due to a need for PID tuning? If so, could you recommend some resources for PID parameter optimization?
Thank you for your time and assistance.