Figure 2.

Coordinate systems of the AMiCUS system. Degrees of Freedom (DOFs) of the same color are controlled by the same head DOF. The zero orientation of the head coordinate system depends on whether the cursor or the robot is controlled. During robot control, the head coordinate system is denoted by ${}^{h_r}\mathbf{\alpha }={ }^{h_r}(\phi ,\vartheta ,\psi ){}^T$ and ${}^{h_c}\mathbf{\alpha }={ }^{h_c}(\phi ,\vartheta ,\psi ){}^T$ during cursor control.