Abstract: The present invention relates generally to a metrology framework for determining the position of a first object, such as an operator, relative to a second object when the first object is moved relative to the second object. The metrology framework comprises a plurality of extensible instrument arms that are operatively connected in proximity to the first object and the second object. A sensor is in communication with each extensible instrument arm to provide a signal indicative of the extension of the instrument arm. The combination of the signals can be used to determine the position of the first object relative to the second object in all six degrees of freedom.

Abstract: A machine such as a machine tool includes a pair of spaced platforms. One platform (11, 31, 185, 72, 159, 142) may mount an operator such as a tool in a spindle and the other platforms (10, 20, 180, 170, 144, 163) may mount an object such as a workpiece. The spaced platforms are joined by six powered and extensible legs (20-25, 40-45, 64-69, 145-150, 166, 182-84, 187-89) joined to the respective platforms by universal joints. The length of the legs is individually manipulated to vary the position of the platforms and, therefore, the object and operator relative to each other in six axes. The powered legs may be hydraulic cylinders (20-25) or recirculating ball screw driven (195, 197, 198). The distance between the spaced platforms may be measured by separate extensible instrument arms (130, 131, 171) which join the platforms. The instrument arms may use a digital position device (238, 240) to measure the extension and contraction of the instrument arms or may use a laser interferometer (267) for that purpose.