Mathematical Model used in UAV toolbox

Greetings.

I want to obtain the mathematical model of the drone used by the UAV toolbox. This will help me develop some controllers based on the knowledge of the mathematical model of the drone. I was unable to find it in the UAV toolbox documentation .

Thanks in advance.

Answer 1

[Jianxin Sun]

Math behind UAV Guidance Models:

multirotor

fixedwing

[Nishanth Rao]

@Jianxin Sun In the mathematical model provided, could you please confirm the equation for the vector ? The has an error term but the derivative term has only a single dot i.e., ? The equation for also seems different than .

Thanks.

[Jianxin Sun]

Thanks for point out this issue in the documentation. The formula is correct but the was wrong, it should be using instead of . We will correct this documentation issue. The actual software implementation is still correct.

[Jianxin Sun]

The control commands are roll (), pitch (), yaw rate (), and thrust (T)

[Jianxin Sun]

The control for roll and ptich angles are similar, their goal is to achieve a given roll/pitch angle with 0 angular velocity. Thus the PD controller is formulated as described in the doc page, with the modification I gave in previous comments. The controller can be see as

[Nishanth Rao]

It seems to me that the equations on the UAV guidance model page hasn't been changed to the right equations.

Also, the rotation matrix described in the page converts vector from inertial frame to body frame (this is also justified from the kinematic equations), but the sentence just above the rotation matrix says the opposite.

This is really frustrating, as these small mistakes can lead to a huge output error while implementing for a non-linear system. I hope these mistakes will be corrected.

Thanks.