A robotic surgery system includes a control unit assembly that supports and operates one or more robotic tools and a mechanical arm assembly that movably supports the control unit assembly in space. The mechanical arm assembly includes a boom assembly with one or more boom arms rotatably coupled to each other via one or more joints and having one or more actuators. An elevating linkage assembly is coupled to the boom assembly and has an actuator operable to allow vertical movement of the control unit assembly in a substantially weightless manner. Yaw and pitch control assemblies are interposed between the elevating linkage assembly and the control unit assembly and have actuators operable to allow movement of the control unit assembly in yaw and pitch. The one or more actuators are actuatable to allow movement of the control unit assembly in space upon actuation of one or more user interfaces of the control unit assembly.