dynamics

[rrwbearz]

Does anyone know of any sites that explain the dynamics of a quadrotor (mathematics)? Thanks.

[eddymoore]

It's not a hard thing to analyse.

You need to understand the mechanics of a rigid body with 6 degrees of freedom. Google for Euler angles and inertia matrices.

Helicopter dynamics and the gyro equations should take care of the rotory part. Again, there's plenty of that on google.

From a control point of view, quadrotors are nice in that, for small deviations from horizontal, you can completely decouple the axes from a control standpoint. So you have two axes, x and y, and the x axis control only cares about x axis sensors and only talks to x axis motor controllers. The same is true for the y axis.

This works ok, but when your comprehension catches up after a few hours of study, you'll want to start looking at things like quaternions. Again, google.

Good luck.

[rrwbearz]

Thanks Eddy. Much appreciated. I was able to dig up some old mechanics textbooks of mine which explained mechanics and kinematics of rigid bodies. Also found another book on quaternions.