Hello friends. While doing a software review on input shaping in the Arducopter software, I came across the rotor thrust angle section in attitude control. Has anyone studied whether the rotor type in helicopter control would change these assumptions? For example, in a helicopter with a teething rotor structure, the thrust vector will not coincide with the vertical axis of the body. Wouldn’t these acceptances create some control delays?
Hi Michael,
I hadn’t thought about that. I guess that it depends on which part of the attitude controller that you are referring. So there is a method (thrust vector rotation angles) that determines the angle between the target attitude and the actual attitude. This is really just determining the difference between the two and it is done with the body axis vertical vector, called thrust vector, so as to compute it in quaternions rather than Euler angles. At least that is my interpretation of that method. @leonardhall may have more to say for that.
The other input methods (input_thrust_vector …) are providing the requested orientation in a different format. Again I think this was done to use quaternions rather than Euler angles to pass the desired orientation to the attitude controller.
So even though thrust vector is used throughout the attitude controller, it is more representing the vertical vector for determining the orientation of the aircraft.
For heli’s we could take this a step further to track the rotor thrust vector, but that would be better suited to be done at the motors library level where the rotor dynamics would be coded in with the appropriate parameters to adjust the behavior.
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Hello Bill,
Can I try to use your heli tuning method for big quad copter ?
Your feedforward méthodologie seems to be more adapted to big multirotor.
But I don’t know if in multirotor type the control algorithm are the same.
Please let me know.
King regards.