1. A method of determining the position of a virtual tool center point used with a robot relative to a known coordinate system of the robot, the method comprising: sensing the position and orientation of a measurement point of a reference component in a sensor coordinate system using a sensor associated with the robot; determining the differences in position and orientation between the measurement point and the virtual tool center point in the sensor coordinate system; and moving the virtual tool center point to be in registration with the measurement point; wherein determining a difference in position between the measurement point and the virtual tool center point comprises sensing at least one positional value along a coordinate axis in the sensor coordinate system, and wherein moving the virtual tool center point to be in registration with the measurement point is based on the determined difference in position; and wherein the method further comprises bringing the sensor into spatial proximity with the measurement point such that the measurement point can be sensed by the sensor.