A robotic surgical system may include a cannula attachment device or cannula mount having a locking mechanism configured to pivot between an unlocked position and a locked over-center position. The locking mechanism may actuate a clamp or other feature that is configured to move between a closed position and an open position. The clamp may include a locating structure with one or more tapered surfaces that is configured to mate with a corresponding structure disposed on a portion of a cannula when the cannula is positioned in the cannula attachment device. The locating structure may guide the cannula into the attachment device, as well as assist with orientating the cannula relative to the attachment device.