Hi,

I'm totally new to this forum so please forgive me if I'm posting this in a wrong folder. I'm working on robotics and I'm currently running in to some rotation problems which kinda run over my head at the moment. I try to understand what I'm doing wrong but can't seems to find what I'm doing wrong. Hopefullly somebody can help me out.

Using a cartesian coordinate system; I'm using a Pitch-Roll-Yaw rotation matrix to calculate the position of point P from from the Origin (O) with the given angles (Z-theta, Y-beta, X-alfa)

the Rotation Matrix:

$\displaystyle Q = Qz,theta * Qy,beta * Qx,alfa$

Q = [cos(b)*cos(t), -cos(a)*sin(t)+cos(t)*sin(a)*sin(b), sin(a)*sin(t)+cos(a)*cos(t)*sin(b)

;cos(b)*sin(t), cos(a)*cos(t)-sin(a)*sin(b)*sin(t), -cos(t)*sin(a)+cos(a)*sin(b)*sin(y)

;-sin(b), cos(b)*sin(a), cos(a)cos(b)]

This equation allows me to calculate the position of point P with the given angles alfa, beta and theta.

$\displaystyle P[x;y;z] = Q * O[x;y;z]$

I'm looking for a method to inverse this matrix. Meaning that I would like to calculate the 3 angles from the 2 given points P[x;y;z] and O[x;y;z].

Can somebody tell me how to find rotations (alfa, beta, theta) from two given positions?

Help is very appriciated!

Thanks!

Xan