The other alternative control modality was a 3D joystick
(Figure 3) which was originally designed for haptic video game
playing by Falcon Technology®. It was reprogrammed and
adapted as a 3D joystick controller for the robotic arm. A
handle developed for users with no finger gripping ability was
positioned in the center of the joystick. The 3D joystick
provides users a method of directed selection to control the
robotic arm elements to move in 3D Euclidean space. The
handle of 3D joystick was positioned at the center of the
joystick as a home (or rest) position if not used by the user.