A surgical system or assembly for performing cardiac surgery includes a surgical instrument (82); a servo-mechanical system engaged to the surgical instrument for operating the surgical instrument; and an attachment assembly for removing at least one degree of movement from a moving surgical cardiac worksite. The surgical system or assembly also includes a motion tracking system (88); and a control computer (34) engaged to the attachment assembly, the motion tracking system and to the servo-mechanical system for controlling movement of the attachment assembly and for feeding gathered information to the servo-mechanical system for moving the surgical instrument.