Mitsubishi XYZ-ABC format¶

The pose format that is used by Mitsubishi robots is the same as that for KUKA robots (see KUKA XYZ-ABC format), except that $A$ is a rotation around $x$ axis and $C$ is a rotation around $z$ axis. Thus, the rotation is computed by $r_z(C) r_y(B) r_x(A)$ .

Conversion from Mitsubishi-ABC to quaternion¶

The conversion from the $ABC$ angles in degrees to a quaternion $q=(\begin{array}{cccc}x & y & z & w\end{array})$ can be done by first converting all angles to radians

$A_r = A \frac{\pi}{180} \text{,} \\ B_r = B \frac{\pi}{180} \text{,} \\ C_r = C \frac{\pi}{180} \text{,} \\$

and then calculating the quaternion with

$x = \cos{(C_r/2)}\cos{(B_r/2)}\sin{(A_r/2)} - \sin{(C_r/2)}\sin{(B_r/2)}\cos{(A_r/2)} \text{,} \\ y = \cos{(C_r/2)}\sin{(B_r/2)}\cos{(A_r/2)} + \sin{(C_r/2)}\cos{(B_r/2)}\sin{(A_r/2)} \text{,} \\ z = \sin{(C_r/2)}\cos{(B_r/2)}\cos{(A_r/2)} - \cos{(C_r/2)}\sin{(B_r/2)}\sin{(A_r/2)} \text{,} \\ w = \cos{(C_r/2)}\cos{(B_r/2)}\cos{(A_r/2)} + \sin{(C_r/2)}\sin{(B_r/2)}\sin{(A_r/2)} \text{.}$

Conversion from quaternion to Mitsubishi-ABC¶

The conversion from a quaternion $q=(\begin{array}{cccc}x & y & z & w\end{array})$ with $||q||=1$ to the $ABC$ angles in degrees can be done as follows.

$A &= \text{atan}_2{(2(wx + yz), 1 - 2(x^2 + y^2))} \frac{180}{\pi} \\ B &= \text{asin}{(2(wy - zx))} \frac{180}{\pi} \\ C &= \text{atan}_2{(2(wz + xy), 1 - 2(y^2 + z^2))} \frac{180}{\pi}$