‫Welcome back.
‫So let's rotate the body frame with respect to the inertial frame by rotating about the fixed axis.
‫So first we rotate about the fixed x axis, like this positive rotation according to the right hand
‫rule.
‫And if you rotated by 90 degrees, then you will get this result.
‫Then you rotate about the inertial y axis and you have this and then about the Z axis and you are here.
‫And now let's do the same thing.
‫But now we rotate about the moving frame.
‫So first we rotate about the body frame x axis by 90 degrees.
‫You get this one, which is the same like this one here, which makes sense because when you rotated
‫about the body frame x axis, then at the beginning your body frame x axis overlapped with the inertial
‫frame x axis.
‫So it's logical that here the result is the same like here.
‫However, now instead of rotating about the inertia frame y axis, you rotate about the body frame y
‫axis.
‫And if you do that, then you will get this result.
‫And finally, you rotate about the body frame Z axis, not the inertia frames the axis, but body frame,
‫Z axis.
‫And you end up having this configuration.
‫There you go.
‫As you can see, it also matters if you rotate about the fixed X, Y, Z axis, which is called a fixed
‫angle approach, or you rotate about the moving X, Y, Z axis, which is called an oiler angle approach.
‫So now you know how to completely determine the position and the orientation of your drone.
‫You have to specify the position of the drone, the orientation angles, whether you use the right hand
‫rule or not, and probably you do because everybody does it.
‫Then you also have to specify the rotation order convention and whether you use a fixed angle approach
‫or an oilor angle approach.
‫But now a question to you.
‫How would you rate the oil or angles in the vector matrix form?
‫And for that, I'm going to give you another exercise again.
‫At the beginning, your body and inertial frames overlap, then make three consecutive rotations each
‫power to radians, first using the R sub X, Y, Z convention using the fixed angle approach and then
‫R sub z, y, x convention using the oilor angle approach.
‫Try to do this exercise by yourself first and see what you will get.
‫See how in both cases the body frames end up in which configuration.
‫See you in the next video.