Abstract: An apparatus determines the position of an object with respect to a reference coordinate system. Preferably, the apparatus includes a target attached to the object, the target moves within a defined region and has a surface with a first pattern thereon. A projection device projects a second pattern upon the surface. A sensing device provides an image signal indicative of the target surface including the first pattern and the second pattern. An analyzer receives the image signal and determines the position of the object based on the position of images of the first pattern and the second pattern.

Abstract: A sensing apparatus for sensing at least two physical quantities is disclosed. The sensing apparatus includes a first transducer that provides a first output signal proportional to a first measured quantity represented and a second transducer that provides a second output signal proportional to a second measured quantity. An excitation regulator device is connected to the first transducer and the second transducer. The excitation regulator device provides an excitation signal to the second transducer so that the second transducer output signal is referenced to the first transducer output signal in order to obtain a resultant output signal which is a combination of the first and second output signals.

Abstract: A material test system capable of applying multiple force load components simultaneously includes a first actuator connected in parallel with a spring element. The first actuator and the spring element in turn are connected in series with the test specimen and a second actuator. The spring element is substantially rigid in order to transfer the force load from the second actuator to the test specimen yet substantially compliant in order to allow transfer of the force load from the first actuator to the test specimen.

Abstract: A feedback control system modifies a drive signal to a plant which provides an achieved response signal in response to the drive signal. A first summing element provides a response error signal representing the difference between a desired response signal and the achieved response signal. An adaptive filter adjusts the response error signal in accordance with a dynamic behavior of the adaptive filter to provide a drive correction signal, the dynamic behavior being adjusted by a compensation device in response to the drive signal and the achieved response signal. A second summing element provides a corrected drive signal representing the sum of the drive signal and the drive correction signal. A storage device delays the corrected drive signal and a converter generates the drive signal during the next iteration as a function of the delayed corrected drive signal.

Abstract: A tester is disclosed that applies forces to selected portions of a vehicle seat. The tester includes force application members that are mounted for pivotal movement about a common pivot axis. Actuators connected to the force application members apply the forces to the selected portions of the back of the seat in either a simultaneous or sequential manner.

Abstract: A structural assembly that measures forces along and moments about three orthogonal axis with very low cross-talk or likelihood of affecting the reading the in one axis from loads and in another axis is disclosed. The assembly comprises a compact assembly having orthogonal links oriented in a nested arrangement in different planes and within recesses of the assembly.

Abstract: A feedback control system provides an adjusted command signal to a plant in response to a command signal having a plurality of command signal components. The plant controls a subsystem and provides a feedback signal representative of the subsystem's achieved response to the adjusted command signal. An adaptive filter adjusts the amplitude and phase of relatively high frequency command signal components in accordance with a dynamic behavior of the adaptive filter. A compensation device adjusts a dynamic behavior of the adaptive filter in response to the feedback signal and the adjusted command signal. In one form of the invention, a low-pass filter passes command signal components of relatively low frequency, and a summing element generates the adjusted command signal in response to the output from the adaptive filter and the command signal components passed by the low-pass filter.

Abstract: A variable rejection level system for a magnetostrictive transducer which improves the detectability of magnetostrictive pulses along a waveguide in the presence of background noise on the waveguide.

Abstract: A structural assembly that measures forces along and moments about three orthogonal axes with very low cross talk or likelihood of affecting the reading in one axis from loads in another axis is disclosed. The assembly comprises a support structure having a longitudinal axis that is positioned on an axis of the plurality of orthogonal axes. The support structure is substantially compliant for moments about the longitudinal axis and substantially rigid for forces along the orthogonal axes and for moments about the non-longitudinal orthogonal axes. Structural elements of the support structure are joined together with elliptical fillets to minimize stress concentration within the structure. A torque cell that measures moments about the longitudinal axis is positioned concentrically about the longitudinal axis either within a cavity located in the support structure or cylindrically around the support structure.

Abstract: A modular magnetostrictive displacement sensor is disclosed having a waveguide of magnetostrictive material extending from a first housing and protected by a member of fiber reinforced composite material. There is circuitry in the first housing for generating electrical pulses along the waveguide and a converter for generating an electrical signal in response to a torsion pulse in the waveguide caused by a magnet disposed proximate the waveguide when the electrical pulse passes the magnet position. In one embodiment the waveguide and its protective member is received within a second housing. One or more magnets may be mounted within the second housing or externally on or near the second housing for movement to the waveguide. Alternatively the sensor may be used without the second housing.

Abstract: A linear position indicator which converts the position of a magnet to an analog voltage. The illustrative sensor incorporates a velocity adaptive noise window to improve sensor performance in the presence of noise.

Abstract: A gas convection assembly is disclosed for maintaining a desired temperature gradient on a test portion of a test specimen. The assembly includes a housing having a chamber defined by bounding walls. The chamber is accessible through apertures in the housing. The housing is positioned relative to the test specimen such that the apertures are substantially aligned along a longitudinal axis of the test specimen with the test portion located in the chamber and end portions of the test specimen that extend out the apertures. A fan is provided to force gas into the chamber to heat or cool the test portion.

Abstract: A density measuring device having a float with a marker provided therein that is connected by a pair of springs to each of the two supports which are on opposite sides of the float along a guide. A sonic waveguide arrangement is provided extending along this guide past at least one of the supports which can measure the relative positions of the float to thereby determine the effective buoyant force on the float and so the density of the fluid in which the float is submerged. Use of a further float permits determining fluid levels.

Abstract: A road simulator for testing components of automobiles using a wheel assembly, including a tire that is to be loaded by simulation of actual road forces. A low mass flexible web harness is placed over the tire and has web extensions loaded in tension in at least one lateral direction for simulating forces transmitted to the tire at the tire patch without having any substantial mass applied to the tire. High strength, low mass webs are used for the loading link and harness, such as a nylon, Aramid fibers , or carbon filament materials. The harness permits simulating very closely the actual friction forces on a tire, particularly in relation to lateral direction loading without having test fixture mass affect the test.

Abstract: A magnetostrictive position measuring instrument for generating square-wave-in-quadrature output pulses indicating magnet position along a waveguide.

Abstract: A clamp assembly for selectively friction clamping a member with respect to a column includes inner and outer threaded portions positioned concentrically around the column and within a housing attached to the member. The inner and outer threaded portions are threaded together to transfer force therebetween. A sealed chamber between the inner and outer threaded portions is selectively pressurized to cause an inner surface on the inner threaded portion to displace inwardly onto an outer surface of the column and the outer threaded portion displacing outwardly to provide frictional resistance to longitudinal movement of the member with respect to the column. The inner thread portion and the outer thread portion have a thread pitch difference to substantially compensate for strain deformation occurring thereupon.

Abstract: A magnetic sight gage sensor comprises a sensor for determining the liquid level in a process vessel utilizing a magnetic float on the interior of a tube. The tube is connected at different levels to a process vessel and contains a liquid that is maintained at the same level as the liquid inside the process vessel. A magnetostrictive displacement transducer is coupled to the tube or sight glass on the exterior of such glass, so it is out of the process fluid. The transducer provides signals indicating the position of the float relative to a reference position on the transducer. The tube or sight glass is made of a non-magnetic material in order to allow transmission of the magnetic field from the float to the transducer.

Abstract: In a feedback control system, a reference input element adjusts the amplitude and phase of a sinusoidal component of a command signal applied to the control system to cancel the transfer effects of the feedback loop, substantially eliminating error between a feedback signal and the common signal. The reference input element processes the sinusoidal component of a command signal through a network metaphor of a trigonometric identity. Adjustment of weights of the trigonometric identity permits arbitrary adjustment of the amplitude and phase of the command signal. A comparison of the command signal and the feedback signal, or of analogous signals, is used as an input to an automated trigonometric identity weight adjustment routine in the reference input element.

Abstract: An extensometer for measuring strain in a specimen on which the extensometer is mounted which has two arms joined together at first ends, and with specimen engaging knife edges at the second ends. The knife edges will engage a specimen at spaced locations, so that when the specimen is subjected to a load, the knife edges will separate, and the amount of separation will be an indication of the strain in the specimen. The distance between the knife edges is known as the "gage length" and the present invention relates to providing for mounting the knife edge contact points in a selected plurality of positions in which the gage length of the extensometer is changed from other of the positions of the knife edges.

Abstract: A system and method for measuring the absolute position of one body which is constrained to move with respect to another body includes a plurality of magnetic identification units, which are adapted to be mounted in a predetermined absolute position on a first body. Each of the magnetic identification units has an identity characteristic that is associated therewith. A Sensor having a transducer is adapted to be fixed to a second body. The transducer is adapted to sense (a) the relative distance of at least one of the magnetic identification units with respect to a benchmark location which is fixed relative to the transducer and the second body. It is also equipped to sense the identity characteristic of the sensed unit. A controller is provided to receive data representing the relative distance and identity characteristic of the sensed unit from the sensor.