A tool holder for use as a surgical assistant, the tool holder including: first and second beam members； a frame； at least one linkage member coupled to the frame and the first and second beam members； a mounting configuration to hold a tool, the mounting configuration being coupled to the first and second beam members； and a drive mechanism mounted with respect to the frame, wherein the at least one linkage member and the mounting configuration are coupled to the first and second beam members in a parallelogram configuration, the drive mechanism is configured to drive a tilt movement of the mounting configuration with respect to the frame by movement of the first beam member with respect to the second beam member to orient the mounting configuration to a tilt angle, and the drive mechanism is configured to drive a pan movement of the tool about a pan axis, the drive mechanism being further configured to orient the pan axis with respect to the frame dependent on the tilt angle.
