Visual guidance of an active handheld microsurgical tool

In microsurgery, a surgeon often deals with anatomical structures of sizes that are close to the limit of the human hand accuracy. Robotic assistants can help to push beyond the current state of practice by integrating imaging and robot-assisted tools. This paper demonstrates control of a handheld tremor reduction micromanipulator with visual servo techniques, aiding the operator by providing three behaviors: "snap-to", motion scaling, and standoff regulation. A stereo camera setup viewing the workspace under high magnification tracks the tip of the micromanipulator and the object being manipulated. Individual behaviors are activated in task-specific situations when the micromanipulator tip is in the vicinity of the target. We show that the snap-to behavior can reach and maintain a position at a target with Root Mean Squared Error (RMSE) of 17.5 ± 0.4 μm between the tip and target. Scaling the operator's motions and preventing unwanted contact with non-target objects also provides a larger margin of safety.