A system of robotic surgery includes components capable of drilling a bore in the cranium of a patient in connection with craniotomy and other cranial surgeries. A perforator associated with such system is controlled by suitable computer-implemented instructions to maintain the perforator tip along a desired trajectory line while moving the perforator bit at locations proximal to such perforator tip in a circular motion, thereby imparting a conical oscillation to the perforator bit relative to the trajectory line. The angle at which the perforator bit is oscillated relative to such trajectory line results in the bore formed in the cranium having a diameter larger than the bit diameter, and the larger diameter and related conical oscillation is selected so as to reduce frictional force opposing withdrawal of the bit from the situs of the bore, thereby reducing the risk of jamming of the bit during its associated operations.