A surgical instrument includes a shaft, an end effector, and an articulation mechanism. The end effector is movable between a first position where the end effector is aligned with a longitudinal axis of the shaft, and a second position where the end effector is disposed at an angled relative to the longitudinal axis. The articulation mechanism includes a proximal gear disposed in mechanical cooperation with the shaft, a distal gear disposed in mechanical cooperation with the end effector, a first lateral gear disposed in contact with the proximal gear and the distal gear, and a second lateral gear disposed in contact with the proximal gear and the distal gear.

A vertical articulated robot has a base installed on a mounting surface, a first axis supported parallel to the mounting surface by the base, a pivot frame rotatable by the first axis, a second axis supported orthogonal to the first axis by the pivot frame, a lower arm rotatable by the second axis, a third axis supported parallel to the second axis by an end of the lower arm opposite to the second axis, a connecting arm rotatable by the third axis, a fourth axis supported orthogonal to the second axis and third axis by the connecting arm, and an upper arm including a holding arm rotatable by the fourth axis, and the first axis enables the second axis, the lower arm, the third axis, and the upper arm to make a substantially vertical circular motion relative to the mounting surface.