Abstract: A measurement system for precisely measuring the distance between two points is disclosed. The measurement system includes a laser interferometer assembly having a beam splitter and a first reflector disposed to reflect a laser beam along a linear path. The laser interferometer assembly cooperates with a deadpath elimination cell having a sealed hollow interior region. The hollow interior region is sealed by at least one window disposed at the end of the hollow interior region proximate the first reflector. A second reflector is disposed on the opposite side of the hollow interior region and is oriented to reflect the laser beam back along the linear path. Thus, the volume and quantity of gas within the hollow interior remains constant to increase the accuracy in measuring the distance between the first and second reflectors.

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.

Abstract: An automatic dynamic error compensator for compensating the position error arising within a servo drive system includes a measuring head which is operative to measure the relative indicated position of two or more measuring vanes on the movable member. The measuring head, together with a feedback transducer, that measures indicated movable member position, are coupled to a feedback system. The feedback system determines the indicated movable member position from the feedback transducer reading and then compares the indicated movable member position to the known vane position upon occurrence of a vane crossing to yield a compensating value.

Abstract: A device (10) for measuring the difference in elevation between first and second substantially horizontal surfaces (12a, 12b) includes first and second chambers (10a, 10b) respectively located on the surfaces (12a, 12b). The chambers contain quantities of a fluid such as mercury (116) and are coupled together through a conduit (20) which enables mercury (116) to flow between them as required, so that the mercury levels in the chambers will be in the same horizontal plane. A first device (140a) is mounted at a first distance above the fluid in the first chamber and at a fixed distance above the first surface (12a). Likewise, a second device (140b) is mounted at a second distance above the fluid in the second chamber, and at the same fixed distance above the second surface (12b).

Abstract: Remote control of a computer numerically controlled (CNC) machine tool is facilitated by an intelligent portable control box coupled to the CNC machine tool through a radio frequency link, typically taking the form of a single conductor coaxial cable. The portable control box includes a transmit/receive circuit and a plurality of input devices and output devices, the transmit/receive circuit, the input devices and output devices all being coupled to, and controlled by a microcomputer. Information from the CNC machine tool indicative of machine tool operating conditions is transmitted across the RF link in the form of carrier keyed radio frequency signals to the portable control box. The transmit/receive circuit demodulates the carrier keyed signals and in accordance with the demodulated signals supplied thereto from the output transmit/receive circuit, the microcomputer renders the output devices operative to display machine tool operating characteristics.

Abstract: An analog signal which occurs in a computer controlled machine tool is converted to digital form at the machine tool site and is stored in a memory portion of the machine tool computer. The digitized analog signal is subsequently read out of the memory and is transmitted to a remote diagnostic unit via a conventional digital transmission link. The digitized analog signal received by the diagnostic unit is stored in a memory portion of the diagnostic computer and is subsequently read out and converted back to analog form for display on an oscilloscope in the diagnostic unit to aid in the diagnosis of existing or incipient faults in the machine tool.