WO1994024534A1 - Capteur a fibre optique pour suspension de vehicule - Google Patents

Capteur a fibre optique pour suspension de vehicule Download PDF

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Publication number
WO1994024534A1
WO1994024534A1 PCT/US1994/003141 US9403141W WO9424534A1 WO 1994024534 A1 WO1994024534 A1 WO 1994024534A1 US 9403141 W US9403141 W US 9403141W WO 9424534 A1 WO9424534 A1 WO 9424534A1
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WO
WIPO (PCT)
Prior art keywords
sensor
suspension
flexible beam
vehicle
fiber optic
Prior art date
Application number
PCT/US1994/003141
Other languages
English (en)
Inventor
Lee A. Danisch
Kenneth M. Cyll
Original Assignee
Control Devices,Inc.
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Control Devices,Inc. filed Critical Control Devices,Inc.
Publication of WO1994024534A1 publication Critical patent/WO1994024534A1/fr

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Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60G—VEHICLE SUSPENSION ARRANGEMENTS
    • B60G17/00—Resilient suspensions having means for adjusting the spring or vibration-damper characteristics, for regulating the distance between a supporting surface and a sprung part of vehicle or for locking suspension during use to meet varying vehicular or surface conditions, e.g. due to speed or load
    • B60G17/015—Resilient suspensions having means for adjusting the spring or vibration-damper characteristics, for regulating the distance between a supporting surface and a sprung part of vehicle or for locking suspension during use to meet varying vehicular or surface conditions, e.g. due to speed or load the regulating means comprising electric or electronic elements
    • B60G17/019—Resilient suspensions having means for adjusting the spring or vibration-damper characteristics, for regulating the distance between a supporting surface and a sprung part of vehicle or for locking suspension during use to meet varying vehicular or surface conditions, e.g. due to speed or load the regulating means comprising electric or electronic elements characterised by the type of sensor or the arrangement thereof
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B1/00—Instruments for performing medical examinations of the interior of cavities or tubes of the body by visual or photographical inspection, e.g. endoscopes; Illuminating arrangements therefor
    • A61B1/005—Flexible endoscopes
    • A61B1/009—Flexible endoscopes with bending or curvature detection of the insertion part
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01D—MEASURING NOT SPECIALLY ADAPTED FOR A SPECIFIC VARIABLE; ARRANGEMENTS FOR MEASURING TWO OR MORE VARIABLES NOT COVERED IN A SINGLE OTHER SUBCLASS; TARIFF METERING APPARATUS; MEASURING OR TESTING NOT OTHERWISE PROVIDED FOR
    • G01D5/00—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable
    • G01D5/26—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable characterised by optical transfer means, i.e. using infrared, visible, or ultraviolet light
    • G01D5/32—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable characterised by optical transfer means, i.e. using infrared, visible, or ultraviolet light with attenuation or whole or partial obturation of beams of light
    • G01D5/34—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable characterised by optical transfer means, i.e. using infrared, visible, or ultraviolet light with attenuation or whole or partial obturation of beams of light the beams of light being detected by photocells
    • G01D5/353—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable characterised by optical transfer means, i.e. using infrared, visible, or ultraviolet light with attenuation or whole or partial obturation of beams of light the beams of light being detected by photocells influencing the transmission properties of an optical fibre
    • G01D5/3537—Optical fibre sensor using a particular arrangement of the optical fibre itself
    • G01D5/35374—Particular layout of the fiber
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01D—MEASURING NOT SPECIALLY ADAPTED FOR A SPECIFIC VARIABLE; ARRANGEMENTS FOR MEASURING TWO OR MORE VARIABLES NOT COVERED IN A SINGLE OTHER SUBCLASS; TARIFF METERING APPARATUS; MEASURING OR TESTING NOT OTHERWISE PROVIDED FOR
    • G01D5/00—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable
    • G01D5/26—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable characterised by optical transfer means, i.e. using infrared, visible, or ultraviolet light
    • G01D5/32—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable characterised by optical transfer means, i.e. using infrared, visible, or ultraviolet light with attenuation or whole or partial obturation of beams of light
    • G01D5/34—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable characterised by optical transfer means, i.e. using infrared, visible, or ultraviolet light with attenuation or whole or partial obturation of beams of light the beams of light being detected by photocells
    • G01D5/353—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable characterised by optical transfer means, i.e. using infrared, visible, or ultraviolet light with attenuation or whole or partial obturation of beams of light the beams of light being detected by photocells influencing the transmission properties of an optical fibre
    • G01D5/3537—Optical fibre sensor using a particular arrangement of the optical fibre itself
    • G01D5/35377—Means for amplifying or modifying the measured quantity
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60G—VEHICLE SUSPENSION ARRANGEMENTS
    • B60G2204/00—Indexing codes related to suspensions per se or to auxiliary parts
    • B60G2204/10—Mounting of suspension elements
    • B60G2204/11—Mounting of sensors thereon
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60G—VEHICLE SUSPENSION ARRANGEMENTS
    • B60G2401/00—Indexing codes relating to the type of sensors based on the principle of their operation
    • B60G2401/14—Photo or light sensitive means, e.g. Infrared
    • B60G2401/144—Fiber optic sensor

Definitions

  • the present invention relates to a sensor for sensing the displacement of the suspension system on a vehicle such as, for example, an automobile.
  • a sensor for sensing the displacement of the suspension system on a vehicle such as, for example, an automobile.
  • Use of the term "displacement” relates to the distance between the axle of any wheel and a reference point on the frame of a vehicle, or to an angular deflection of an upper or lower control arm connecting a wheel assembly to the frame of a vehicle, or to an angular deflection of a torsion bar providing a suspension force between a wheel assembly and the frame of a vehicle, or to axial deflection of a coil or air spring providing a suspension force between a wheel assembly and the frame of a vehicle, or to various combinations of the foregoing or other related displacements.
  • the present invention uses a fiber optic bending and positioning sensor as described in U.S. patent applications Serial No ⁇ 07/738,560 filed on July 31, 1991, and entitled Fiber Optic Bending and Positioning Sensor and Serial No. 07/915,283 filed on July 20, 1992, and having the same title, each naming Lee A. Danisch as inventor.
  • Such bending and positioning sensors are also described in "Bend-enhanced Fiber Optic Sensors", SPIE: The International Society of Optical Engineering, L.A. Danisch, Volume 1795, 204-214, September, 1992, Boston, MA, USA; "Smart Bone", Final Report for Canadian Space Agency Contract 9F006-1-0006/01-OSC, L.A.
  • the control of displacement of a suspension system will be automatic and will be useful to enable maintenance of a constant suspension displacement over a wide range of weight being carried by the automobile.
  • a smoother ride will be provided when travelling over rough roads or when cornering or braking occurs.
  • the automatic control of the displacement of the suspension system also enables variation of the average displacement for various operating conditions such as high speed.
  • a sensing means which converts geometrical displacement to a signal which may talce the form of a continuously variable electrical parameter such as current or voltage or a continuously variable optical parameter such as intensity.
  • a signal is capable of driving a display which indicates the degree of displacement of the suspension system.
  • Control means may also be responsive to such a signal to control the displacement of the suspension system to the extent desired, actual control being exerted in response to sensor signals by means of pneumatic, hydraulic or electromagnetic means and the like.
  • One control means commonly used in the automotive industry are air springs.
  • a number of technologies may be adapted for use in providing means for sensing the displacement of a suspension system. These include linear variable displacement transformers, linear potentiometers, linear encoders, linear capacitance sensors, linear magnetic reluctance devices, and their rotary counterparts.
  • Such sensors typically include mechanical parts which are subjected to relative motion to sense any change in distance between an axle of a wheel and the frame of the vehicle.
  • linear sensors generally include two concentric mechanical parts, such as a piston and cylinder, which move with respect to each other. Each such part is attached to reference points associated with either the vehicle frame or the wheel assembly.
  • motion of the reference attachment points generally involves a combination of vertical translations and angular deflection with at least two degrees of freedom due to the use of flexible rubber torsional bushings to attach control arms to the frame.
  • the sensors, and any sealing means associated therewith must be low in cost and easy to manufacture.
  • the mechanical complexity of sensor means having multiple moving, sliding parts may tend to provide poor reliability and are costly and difficult to manufacture.
  • a less complex structure is particularly desirable considering that sensors must normally not require maintenance or replacement for long time or travel periods, typically 10 years or 150,000 miles.
  • the sensors must be easy to install.
  • the present invention provides an improved sensor means for sensing automatically and/or controlling the displacement of a suspension system and particularly a suspension system of a vehicle such as, for example, an automobile.
  • An object of the present invention is to provide such a sensor means which is not mechanically complex yet provides desirable reliability.
  • a further object of the present invention is to provide such a sensor means which does not include mechanical parts which move with respect to each other.
  • Yet a further object of the present invention is to provide such a sensor which is not adversely a fected by the operational environment.
  • Another object of the present invention is to provide such a sensor which does not require a sealing means.
  • a further object of the present invention is to provide such a sensor which is low in cost and easy to manufacture and install.
  • Another object of the present invention is to provide such a sensor which does not normally require maintenance or replacement for long times and travel periods.
  • a suspension sensor comprising a flexible beam and a fiber optic bending and positioning sensor mounted to the flexible beam.
  • the curvature of the beam when flexed adjacent a treated zone of the fiber optic bending and positioning sensor is linearly responsive to suspension displacement over at least a full range of travel of suspension and the range of such curvature is within the linear response range of the fiber optic bending and positioning sensor.
  • linearization may be effected by processing sensor signals using a microprocessor or analog circuit.
  • the suspension sensor of the present invention is useful in a vehicle suspension system which includes an electronic measuring system for sensing and controlling displacement between a vehicle frame and/or body and a vehicle wheel system.
  • Figure 1 is a diagrammatic illustration of a bending sensor apparatus, with the sensor shown cemented to a bending beam;
  • Figure 2 is a cross-section through a fiber optic bending and positioning sensor
  • Figure 3 is a cross-section similar to that of Figure 2, illustrating a modification thereof;
  • Figure 4 is a perspective view, on a large scale, of part of a light guide showing a form of surface treatment;
  • Figure 5 is a side elevation of the light guide of Figure 4;
  • Figure 6 is a transverse cross-section of the sensor as on line X-X in Figure 5;
  • Figure 7 illustrates an alternate form of surface treatment of the light guide
  • Figure 8 is a side elevation of the light guide of Figure 7;
  • Figure 9 is a transverse cross-section of the sensor as on line Y-Y of Figure 8.
  • Figure 10 is a transverse cross-section of a sensor showing the axes of maximum and minimum sensitivity to bends
  • Figure 11 is a perspective view of a sensor employing a non-emitting reference fiber paired with an emitting, sensing, fiber;
  • Figure 12 is a perspective view of a triple sensor for detecting the three dimensional bend vector
  • Figure 13 is a cross-sectional view of the triple sensor on the line Z-Z of Figure 12, showing the 120° arrangement of emitting sections;
  • Figure 14 is a schematic diagram showing light paths and electronic circuitry
  • Figure 15 shows an alternative form of the light guide return path
  • Figure 16 shows an alternative application of the sensor, to measurement of position
  • Figure 17 is a perspective view of a suspension sensor of the present invention including a curved flexible beam and fiber optic bending and positioning sensor mounted thereto;
  • Figure 18 is a view of the suspension sensor of Figure 17 mounted to a vehicle suspension system
  • Figures 19 to 23 are alternative embodiments of a suspension sensor of the present invention mounted to a vehicle suspension system
  • Figure 24 is a view of a vehicle suspension system embodying the suspension sensor of the present invention.
  • Figure 25 is a schematic diagram showing light paths and electronic circuitry of a preferred embodiment.
  • FIGS 26 to 29 are graphs representative of various applications of the present invention as described herein.
  • a fiber optic bending and positioning sensor comprises a fiber optic light guide having a light emission surface extending in a thin band on a side of the fiber for at least part of its length.
  • This surface can merely be the exposed surface of the fiber core or the exposed surface can be textured, for example, have serrations, corrugations or other roughness. This leads to bending or position sensors with particular characteristics. In all cases, including where the surface of the fiber is merely exposed and when the surface is textured, the light transmitted increases for bends in which the light emission surface becomes concave outward from the axis of the fiber, and decreases when it becomes concave inward.
  • the percentage change of light for bends in the plane of maximum sensitivity is greater for textured surface fibers than for untreated fibers, but both provide measurement with simple instrumentation for small angles of bend.
  • untreated fibers is meant fibers which have a smooth exposed core.
  • the sensitivity is approximately that obtainable with resistance strain gauges, but the sensor requires no elongation of the material to which it is mounted to obtain a response. The sensor could be located along the neutral axis of a bending beam, and still indicate bending angle.
  • fibers are composed of a core and a cladding, usually with a buffer layer and a jacket placed over the cladding to protect it.
  • the exposed surface referred to is the exposed core.
  • the fiber can be fused quartz, or of plastic material.
  • a sensor made in this way has distinct advantages over other fiber optical sensors used to measure displacement or bending.
  • a single straight fiber treated in this way can be used to measure very small angles of bend, using simple instrumentation which measures only the percentage of light passing from one end of the fiber to the other.
  • the same single fiber sensor indicates direction of bending, so that two or more parallel fibers attached to a structure and arranged to have maximum sensitivity planes at angles to each other could be used to measure the bending vector, indicating magnitude and direction in three-space of the bend.
  • a triplet of fibers arranged to have axes of maximum sensitivity at 120° to each other is analogous to a strain gauge rosette, which measures the strain vector in the plane of the rosette gauge.
  • Fibers having roughened or similar surfaces for light emission are described in U.S. patent 4,880,971 in the name of Lee A. Danisch, one of the present applicants.
  • a fiber optic bending, and positioning, sensor comprises a fiber optic light guide having a light emission surface extending in a relatively thin band on one side of the fiber for at least part of its length.
  • a light emission surface can be the bare surface of the fiber core with the cladding, coating, and buffer layer if present removed locally, or the surface can be textured by serrations, etching, or abrasion or other, such that light can leak out through only that portion of the circumference of the fiber.
  • Lengths of fiber beyond the part having the emission surface serve as light guides to convey light to and from the part.
  • the emission surface is positioned so that bending of the fiber affects the light transmission effect of the surface.
  • the amount of light is measured by standard techniques.
  • One such technique would employ a light emitting diode at one end of the fiber, and a photodiode at the other. It is not necessary to use special mode- enhanced fibers or special light sources.
  • the light may be monochromatic or of broad spectrum.
  • coatings would include semi-opaque adhesives with a high index of refraction, graphite or dye-filled epoxies, a surrounding metal or plastic sleeve filled with epoxy, and heat-shrinkable tubing. It is possible to employ fibers of virtually any diameters. Fibers with core diameters of 0.125 to 1.0 mm have been used.
  • Bending changes the portion of light able to escape from the emission surface, in such a way that bends which make the treated region concave outward decrease the loss of light, and opposite bends increase the loss of light.
  • the strip of emission surface of the fiber can vary in length from a few millimeters to meters.
  • the output signal will represent the average bend of the strip.
  • the application of torsion and axial tension to the fiber have negligible effect on the output.
  • the only important input is bending.
  • the fiber is very limp in bending, and responds only to bending angle, not to elongation of the member to which it is attached. Therefore it requires virtually no force to produce an output.
  • An amplifier would be used to detect the amount of light falling on the photodetector. Standard techniques can be used to improve sensitivity.
  • One method that has been used is to chop the light by rapidly turning on and off the light emitting diode, and employing synchronous detection in the amplifier. This has the advantage of eliminating many types of electric noise and the effects of stray light.
  • Another method is to employ a reference channel that passes some of the light through a non- emitting fiber, such that all measurements are referenced to this channel. This has the advantage of greatly diminishing the effects of variations in the light source and electronic circuits, and effects in the fiber optics not originating in the emission strip.
  • Various forms of display, recording and control can be provided.
  • Figure 1 illustrates a bending sensor 10 mounted with adhesive on bent beam 11.
  • light is conveyed from a photo-emitter 12 through a plastic or other optical fiber light guide 13 to the sensor portion 10, and thence through guide 14 to a photo-detector 15.
  • the light guide near the sensor region 10 has had its outer protective jacket removed, and the light conducting core exposed along a strip on the surface; portions 13 and 14 leading to the sensor region may have the jacket in place.
  • the sensing portion 10 is adapted to sense bending.
  • the photo-emitter 12 and photo-detector 15 are part of an electronic measuring system 16 and display 17.
  • Figure 2 illustrates, in cross-section a conventional optical fiber wave guide 18 having a light conducting fiber 19 and a cladding 20.
  • the cladding is removed locally, at 21, extending in a band along the fiber 19, to form a light emitting surface 22.
  • the band can be formed by deliberately removing cladding as by abrasion, melting, etc. or by displacement as by pressure or rubbing on the fiber, for example by a heated tool, depending upon the particular form of fiber.
  • Figure 3 illustrates a modification of the arrangement of Figure 2, in which the light emitting surface band 21 is covered with a light absorbent material 20a.
  • Typical materials for the coating 20a are graphite filled epoxy resin, dye-filled resins and similar materials.
  • the use of the coating 20a prevents emitted light interfering with any other instrument or structure and also prevents any back reflection into the fiber, which would affect the measurements.
  • the additional coating 20a can be applied only over the band 21, but more commonly is applied around the entire fiber.
  • FIGs 4, 5 and 6 illustrate one example of a fiber 19 with the emitting surface textured.
  • Serrations 23 have been created on one side of the fiber, as by pressing it onto the surface of a file. Similar serrations can be created by heat forming and molding. Both plastic and glass optical fibers can be so formed. Heat forming can be accomplished by pressing the fiber slightly onto a heated metal surface which can be serrated, corrugated, or otherwise formed. The angle of the serrations can vary. It is not necessary to first remove the cladding of the fiber as this will be displaced. After treatment, a sensor portion emits some light along the length while transmitting a portion of any light within it to either end.
  • Figures 7, 8 and 9 illustrate another form of serration of a fiber 19.
  • the wedge- shaped serrations 23 of the sensing portion 10 are separated by small spaces 24.
  • the exact shape of the serrations can vary considerably.
  • Diamond-shaped serrations have also been successfully used. These are formed by pressing the fiber against a file with a pattern of intersecting serrations.
  • one side of the fiber can be abraded by sanding, sand-blasting, etching, or other means of removing or changing the cladding layer.
  • Figure 10 illustrates the axes of maximum and minimum sensitivity, and the direction of signal change of a bending sensor.
  • the light emitting surface band is 22 at the top of the sensing section of the fiber. Bends within the vertical plane containing A-A produce the maximum change in transmission of light through the fiber. Thus A-A is called the axis of maximum sensitivity. For bends concave upward, the transmission increases. For bends concave downward, the transmission decreases. The minimum change in transmission occurs for bends in the horizontal plane containing B-B. Bends in this plane produce negligible change in transmitted light, so B-B is called the axis of minimum sensitivity. Intermediate response occurs for bends off the major axes, such as at C-C.
  • This intermediate response is a cosine function of the angle between the plane of maximum sensitivity and the plane of the angle of the bend.
  • + and - signs have been placed to indicate increases and decreases in transmitted light relative to the transmission of the fiber when it is straight.
  • the surface band 22 can be just bare fiber, as in Figure 2, or textured, as, for example, in Figures 4 to 9.
  • Figure 11 illustrates a sensor including a paired reference fiber. Fiber 19 has a sensing portion 10. Fiber 25 has no sensing portion. The pair are used in dual detection methods, where all measurements are referenced to the transmission through fiber 25.
  • fiber 25 is arranged mechanically in the same way as fiber 19, most errors are eliminated from the measurement, by virtue of the fact that untreated fibers show little change in transmission for small bend angles (roughly less than 20°, whereas formed fibers are optimized for response to bending) .
  • Figure 12 illustrates three fibers, arranged to form a sensing system capable of detecting the three- dimensional vector describing the applied bend.
  • Each fiber has a light emission portion 10, just bare fiber or formed with serrations or abrasions.
  • the sensing portions are arranged so that the axes of maximum sensitivity are at 120" to each other.
  • Figure 13 shows this relationship more clearly. Solving simultaneous equations for the magnitude and sign of the transmissions of the fibers will yield the three components of the bend vector of an element, such as a beam, to which the sensor has been affixed.
  • Alternate arrangements of the fibers are possible, such as having the sensing portions facing at different angles, triangular rather than flat bundles, or having the fibers separated from one another.
  • the fibers are conventional in that they are composed of the main fiber, of glass, plastic or other, with a cladding layer. The cladding layer is locally removed at the sensor positions 10 as mentioned above, by various means.
  • Figure 14 illustrates one simple example of electronic circuitry that can be used to measure the transmission of light through a paired sensor element such as that shown in Figure 11.
  • fiber 19 (shown coiled to indicate arbitrary placement and length of the guide conveying light to and from the sensing portion) has the light emitting strip at 10.
  • Both fibers are illuminated by photoemitters El and E2, which are light emitting diodes.
  • Photodetectors DI and D2 which receive light from the fibers, are PIN photodiodes, backbiased with 12 Volts to enhance the speed of their response to light energy.
  • Ul and U2 are high input impedance operational amplifiers arranged as transimpedance amplifiers, converting light energy linearly into voltages fed to the inputs of U3, which is an operational amplifier connected as a differential amplifier with a gain of 10.
  • the gain of amplifier U2 can be varied with Rl so that for a straight fiber, the inputs to U3 are equal.
  • the optoelectronic circuit is analogous to a two-armed bridge such as is used to make strain-gauge measurements. Errors due to degradations in the fibers, connector variations, temperature fluctuations, and the like tend to cancel before reaching the output of U3.
  • the output of U3 is a voltage which varies with bending at the band portion 10.
  • the output voltage can be further amplified and sent to a display unit or used to control various parameters, such as actuators designed to minimize the angle of bend.
  • circuitry is possible, including variations with much greater immunity to error sources.
  • One such variation would use the same light source and detector, separating the signals by chopping them at different frequencies and employing synchronous detection.
  • Another variation is to replace U3 in Figure 14 with a divider circuit, so that the sensor signal is divided arithmetically by the reference signal.
  • Figure 15 illustrates a variation of the sensor design which eliminates loops of light guide past the sensing portion.
  • Light from a photo-emitter enters the system through guide 19 and passes through the sensing portion 10.
  • Another sensing portion 27 faces sensing portion 28 on guide 29.
  • Guide 29 carries light back to a photo-detector.
  • the junction region at 27 and 28 is held rigidly by the cap and adhesive so that it does not respond to bending. This arrangement allows the use of parallel fibers without return loops, which can be an advantage when embedding the sensors in long, narrow structures.
  • the ends of the fibers inside the cap may simply be cleaved orthogonally (or at other angles) to the long axis of the fiber, with the fibers otherwise not being modified to have sensing portions.
  • Light from one fiber may be partially directed into the second fiber by filling the cap with a semi-opaque material that diffusely reflects and or refracts the light so that a substantial portion is transferred from one fiber to the other.
  • Suitable diffusing materials include clear epoxy with an added dye or clear epoxy containing a suspension of small particles such as silica microspheres.
  • the cap may be eliminated or may be non- reflective, as the diffusing materials are sufficient to provide coupling from one fiber to the other.
  • the cap is of reflective material such as smooth metal and is arranged to have the inner portion of its end face spaced a short distance away from the fiber ends. At a particular distance, reflection of light by the cap from the first fiber into the second fiber will be maximal. This distance is of the order of one to several fiber diameters.
  • the cap may be filled with clear adhesive, such as epoxy or light cured index- matching adhesive.
  • a mirror can be used to reflect light from the distal end of the sensor fiber back into a return fiber.
  • a directional coupler can be used with a single sensor fiber which has a mirror mounted at its distal end. The coupler is used to pass light to the proximal end of the fiber from the emitter, and to direct reflected light emanating from the proximal end of the fiber, into the detector. Typically, the directional coupler would be placed between the emitter, the detector, and the proximal end of the floor.
  • a loop-back its size may be minimized by heat-forming the fiber to have a permanent small-radius bend, which may be held rigid by cementing it to the substrate. Although this may be done to glass or silica fibers, it is most convenient to heat form plastic fibers, which may be held thusly in a permanent bend with a radius of a few millimeters.
  • Figure 16 illustrates the application of the bending sensor to the measurement of displacement.
  • Vertical displacement 32 between blocks 33 and 34 (representing, for example, moving parts of a mechanical system), is measured by a bend-sensing region 10 in guide 19, cemented into flexible beam 35, which is attached to the two blocks. Similar fixturing, with or without a flexible beam, would enable the measurement of angles, such as pedal position, over a large range.
  • the width of the emission band around the circumference of the fiber will determine the sensitivity of the fiber to bends, with wider bands producing a large percentage change per degree of bend. However, very wide bands will tend to increase the sensitivity to bends in the axis of minimum sensitivity. Typical sensors have emission bands that cover 5 degrees to 30 degrees of the circumference of the fiber, but other values will work, including bands covering 180 degrees or more of the circumference.
  • the length of the emission band can vary. It can be any length from millimeters to meters but there is less gain in sensitivity for long lengths, than expected. There is an optimum length for the strip, which is a function of the diameter of the fiber, its emission band width, the treatment method and the minimum linear deflection angle desired.
  • Long sensors can be formed by alternating lengths of fibers with an emission strip with lengths of fully clad fibers. Short sensors will be less sensitive, but more specific as to location of bend along the length of the member to which they are attached. However very short sensors can be made, such as 8 mm sensors on 125 micron fibers.
  • Sensors in accordance with the invention have various advantages, and useful characteristics. No special electronics are required to measure interference patterns, it is only necessary to measure the amount of light transmitted. Cost is orders of magnitude below that for interference (OTDR) techniques. Sensitivity is in the same range as that of resistance strain gauges. For many situations, particularly when the sensors are mounted near the neutral axis for a bending beam, changes in signal per microstrain are greater than those for resistance strain gauges, as measured in percent. The linear range is very large. They are particularly suited to measurement of bending in aircraft wings, helicopter blades, machinery, robot arms, or large structures. They are not affected by temperature, since measurement is not dependent on small changes in length of the fiber or its sensing portion. This is a distinct advantage over resistance strain gauges, which have a relatively narrow range of temperature resistivity unless compensated, and over interference techniques, which are affected even more by temperatures than are resistance gauges. They can be used to measure position, with a large dynamic range.
  • the present invention uses bending and positioning sensors which may be treated over a short zone as described herein to impart qualities including sensitivity, linearity, polarity and directionality. Typically, such sensors will be treated over a length of about 8 mm. Such sensors will typically be 3000 times more sensitive to curvature than an untreated fiber. Light transmission through the treated zone will be linearly responsive to curvature over a range of 150 degrees per centimeter of treated zone. Light throughput will increase for positive bends in a plane and will decrease for negative bends. The response to bending will be maximum in a plane of maximum sensitivity and will decrease as a cosine function to zero or near-zero in a plane orthogonal to the plane of maximum sensitivity.
  • the fiber optic bending and positioning sensor thus far described herein is hereinafter referred to as a BEF (bend enhanced fiber) sensor.
  • the suspension sensor of the present invention comprises a flexible beam, which is attached at its ends to reference points related to a frame and/or body, and wheel positions, of a vehicle and a fiber optic bending and positioning (BEF) sensor of the type described above.
  • the BEF sensor is mounted to the flexible beam.
  • the curvature of the beam when flexed adjacent a treated zone of the fiber optic bending and positioning sensor is linearly responsive to suspension displacement over at least a full range of travel of suspension and the range of such curvature is within the linear response range of the BEF sensor. This combination will produce an output signal from the BEF sensor that is linearly and monotonically related to suspension positioning.
  • the geometry of the flexible beam may be arranged such that its curvature near the attachment point of the BEF sensor will be relatively unchanged when curvature of other parts of the beam is changed due to external forces such as, for example, impacts from debris, or the ends of the beam are displaced outside of the plane that the flexible beam occupies, or torques are applied around the long axis of the beam, especially at its ends.
  • the suspension sensor includes a thin flexible beam preferably having a rectangular cross section curved in a roughly circular or parabolic arch such that the attached BEF sensor has its treated zone arranged parallel to the long axis of the beam, near the apex of the arch, on the wider surface of the rectangular cross section.
  • the curvature tends to take on a value that does not vary significantly over the length of the arch in the vicinity of the sensor.
  • external forces applied to the sides of the arch will have a minimal effect on the average curvature near the peak of the arch, which is being sensed by the BEF sensor.
  • the cross sectional shape resists bending of the substrate except in the degree of freedom expressing the curvature of the arch, so that external forces applied to lines outside the plane of the arch will have little effect on the sensor reading.
  • the BEF sensor is relatively immune to torques about its long axis, which are diminished in any event by the shape of the cross section and the length of the arch, so that torques applied around the long axis of the arch at its attachment points to the parts being measured will have little or no effect on the sensor readings. Because of a combination of the torque immunity and relative immunity to forces applied along lines out of the plane of the arch, the sensor is relatively immune to displacement of its attachment points outside the plane of the arch.
  • a suspension sensor 100 includes a curved flexible beam 102 having a rectangular cross section 104 and being curved in an arch 106 having an apex 108.
  • Arch 106 will be equal to or less than 360 degrees but greater than 0 degrees. In the embodiment of Figure 17, arch 106 is about 180 degrees.
  • a BEF sensor 110 is mounted to the curved flexible beam 102 such that the treated zone 112 of the BEF sensor is located at the curvature provided by the arch 106.
  • the treated zone 112 is arranged parallel to a long axis 114 of the curved flexible beam 102 near the apex 108 of the curved flexible beam on the wider outer surface 116 of the rectangular cross section 104.
  • Figure 18 schematically depicts the suspension sensor 100 of Figure 17 mounted to a vehicle for use in control of the displacement of the suspension system thereof.
  • Figure 18 depicts a portion of a vehicle 118 including a portion 120 and a control arm 122.
  • the suspension sensor 100 is mounted between the portion 120 and the control arm 122 such that one end 124 of the curved flexible beam 102 is attached to the portion 120 by a bolt 126 and an opposite end 128 of the curved flexible beam is attached to the control arm 122 by a bolt 130.
  • the control arm 122 is moveable relative to the portion 120 in the direction of arrow 132 by virtue of the pivotal connection at 134.
  • the portion 120 of the vehicle 118 may be a vehicle frame, the body of the vehicle and the like but is referred to herein merely as the frame.
  • the arch 106 is about 180 degrees.
  • the suspension sensor 100 By locating the suspension sensor 100 further away from the pivotal connection at 134, the suspension sensor will be sensitive to angular and linear deflections of the control arm relative to the frame.
  • the suspension sensor By mounting the suspension sensor closer to the pivotal connection at 134 the suspension sensor will be predominantly sensitive to angular deflection.
  • the senor of the present invention may be mounted in several different ways that can affect its linear range. This can be used to make the sensor read in a linear portion of its range without any adjustments other than the design of brackets that hold it -to the parts being measures.
  • Figures 19 to 21 schematically depict three other suspension sensors mounted between a frame 120 and a control arm 122, like reference numerals designating like elements.
  • opposite ends of a suspension sensor 100 are mounted to the frame 120 and control arm 122 of the vehicle 118.
  • the arch 106 is about 90 degrees and the treated zone 112 of the BEF sensor 110 is mounted on the wider inner sensor surface 116 of the rectangular cross section of the curved flexible beam 102.
  • This embodiment is particularly useful near the pivoted connection 134 where angular deflections predominate over linear deflections, the sensor of Figure 19 mounted in this manner being predominantly sensitive to angular deflection.
  • the arch 106 is about 360 degrees and the treated zone 112 of the BEF sensor 110 is mounted on the wider outer surface 116 of the rectangular cross section of the curved flexible beam 102.
  • the suspension sensor will sense angular and linear deflection.
  • a suspension sensor 100 is provided which is mounted in such a manner that deflection of the control arm 122 relative to the frame 120 will cause the opposite ends of the curved flexible beam 102 to move in a manner that widens or narrows the arch 106 depending upon the direction of movement of such ends relative to each other, movement of the ends towards each other narrowing the arch and movement of such ends away from each other widening the arch.
  • the ends 124', 128' of the curved flexible beam 102' are disposed, relative to each other and the frame 120 and control arm 122 which each is respectively attached to, for movement along the long axis 114' of the curved flexible beam in response to movement of the control arm 122 relative to the frame 120.
  • end 124' will move in the direction of arrow 136 and end 128' will move in the direction of arrow 138.
  • the BEF sensor 110 is mounted to the outer surface 116' of the curved flexible beam 102' at a position where a curved portion of the curved flexible beam will effectively pass over the BEF sensor during relative movement between the frame 120 and mounting arm 122.
  • the location of the sensor 110 will change as the arch effectively "rolls" upon itself in order to measure displacement.
  • a suspension sensor having a non-curved flexible beam which is approximately straight at the center of the range.
  • the flexible beam includes a first segment 142 and a shorter second segment 144 orthogonal to the first segment 142.
  • a BEF sensor 110 may be mounted upon the first segment 142, or alternatively, as depicted in phantom lines at 110' upon the second segment 144.
  • an "L"-shaped spring is provided having a short leg 144 which permits some right- left motion as depicted by arrow 146 while responding to deflection in the direction of arrow 148.
  • Figure 23 depicts another embodiment of the present invention wherein the curved flexible beam of the suspension sensor comprises at least one turn 150 of a spring such as helical spring 152.
  • the BEF sensor 110 is mounted at the turn 150 as depicted in the drawing.
  • Spring 152 undergoes linear deflection in response to relative movement between frame 120 and mounting arm 122 such that the BEF sensor 110 will read the changes in curvature of the turn 150.
  • any configuration of arch -mounted or spring-mounted sensor may be mounted inside, around or next to a typical air spring.
  • the helical spring 152 may be mounted within an air spring 154 of known construction.
  • such an air spring will include a flexible wall 156 which may be fabricated from rubber.
  • the arch of the turn 150 and the BEF sensor 110 attached thereto are disposed in a sealed environment so that damage from outside sources is virtually impossible.
  • the arch of the curved flexible beam and the BEF sensor attached thereto may be placed inside a rubber hose, corrugated pipe or other covering which provides a sealed environment.
  • the sensor since the light in the system is completely contained in an optical fiber, the sensor will be immune to the effects of water, dirt, etc. even without protection by a hose or the like.
  • the wall 156 may constitute the curved flexible beam in which case the BEF sensor 110 depicted in Figure 23 may be replaced by BEF sensor 110' which as depicted in phantom lines is mounted relative to the flexible wall.
  • the BEF sensor 110' may be mounted on the curving portion of the flexible wall 156 as depicted in Figure 23 or may be embedded in such curving portion.
  • vehicle 118 includes a frame 120 and a control arm 122 having one end pivotally connected relative to the frame at pivotal connections 134 and an opposite end attached to a wheel system 160 which includes the usual axle, not shown.
  • a suspension sensor of the present invention such as the suspension sensor 110 depicted in Figures 17 and 18 is mounted to the frame 120 and control arm 122 as described herein.
  • Light is conveyed from a photo-emitter 162 through a plastic or other optical fiber light guide 164 to the sensor portion 108 of the BEF sensor 110, and then through guide 166 to a photo- detector 168.
  • the sensing portion 108 senses bending of the BEF sensor 110 caused by displacement of the control arm 122 relative to frame 120, the control arm being displaced by virtue of displacement of the wheel system 160 to which it is attached.
  • the photo-emitter 162 and photo-detector 168 are part of an electronic measuring system 170 which responds to changes in the intensity of light caused by such displacement to control an air valve system 182.
  • the embodiment depicted in the schematic diagram of Figure 25 is a simple form of such an electronic measuring system in those instances where the suspension sensor 110 is a paired sensor element such as that shown in Figure 11.
  • the sensor and reference fibers need not be paired.
  • the reference fiber may be provided such that it does not leave the electronics enclosure, as it is not expected that it will be necessary to compensate for lead bending or darkening of the sensor fiber, but only for variations in intensity of the light source and sensitivity of the detectors.
  • fiber 172 (shown coiled to indicate arbitrary placement and length of the guide conveying light to and from the treated section) has the light emitting strip at 174.
  • Fiber 176 which is otherwise the same as fiber 172, has no treatment at 178, which represents a section of the fiber in close proximity to sensor section 174.
  • Both fibers are illuminated by a single photo-emitter El, which is a light emitting diode.
  • Photodetectors Dl and D2 which receive light from the fibers, are PIN photodiodes kept in close proximity to each other so that changes in temperature will affect their sensitivities in a closely matched way.
  • Ul and U2 are high input impedance operational amplifiers arranged as transimpedance amplifiers, converting light energy linearly into voltages.
  • the gains of these two amplifiers can be adjusted by means of variable resistors Rl and R2.
  • the noninverting inputs of Ul and U2 are connected to junction point A, which is held at a constant fraction (approximately 49 mV) of the power supply voltage Vcc (nominally 5 V) by virtue of the resistor divider chain R3, R4, and R5.
  • junction A This connection to junction A together with another connection of U4 to junction B as described below, ensures that the output voltages of Ul and U2 include an offset voltage which reflects changes in the power supply voltage Vcc, so that ultimately the output voltage of the entire sensor circuitry, Vout, will be approximately ratiometric to the supply voltage Vcc.
  • the positive voltage at A also prevents false signals due to operating the inverting inputs of some single-voltage-supply operational amplifiers near ground potential.
  • the output of Ul is fed to operational amplifier U3, which serves to amplify the voltage proportional to the intensity of light travelling through the treated fiber, and to allow for addition of an offset voltage supplied by the resistor divider formed by R6 and R7.
  • the output voltage of U3 is applied to the output terminal Vout, through transistor Tl, which serves to supply current to devices, such as an electronic control module, 180 in Figure 24, performing active suspension control, connected to the sensor electronics which may exceed the current sourcing capabilities of U3.
  • Rl and R6 may be used to adjust gain and offset, respectively, of the electronics connected to the treated fiber.
  • the output of U2 is connected to operational amplifier U4, which provides an output signal proportional to the intensity of light travelling through the untreated reference fiber.
  • Transistor T2 provides the output of U4 with enough current sourcing capability to operate photo-emitter El, which is connected to T2 via junction point C.
  • Operational amplifier U4 has its noninverting input connected to junction point B, which is maintained at a constant fraction of the supply voltage Vcc, by virtue of resistor divider chain R3, R4, R5.
  • This voltage provides a reference to the amplification chain U2, U4, T2, so that the light intensity of El is maintained at a level minimally affected by ageing of the photo-emitter or fibers, changes of the photo-emitter intensity due to temperature changes, or effects such as bending of the untreated portions of the leads (in the case where the fibers 172 and 176 follow the same physical pathway and are bent in the same fashion), or changes in the sensitivities of the two photodetectors. Voltages from junction points A and B are applied to the circuit in such a way that the output voltage Vout is approximately ratiometric with the supply voltage Vcc. Potentiometer R2 Is used to adjust the illumination setpoint of the photo-emitter El.
  • circuitry are possible, and will be readily apparent to those skilled in the art. These include, but are not limited to, variations including a sensor and reference path that are combined by subtraction or division so that common-mode errors have a minimal effect on the output signal, and variations in which no reference is used.
  • a time derivative of the displacement signal may be obtained for use in suspension control. Circuitry need not be based on continuous (in time) light signals. It is possible to use chopped or pulsed light should it be necessary to minimize the effects of stray light or to reduce drift of the signals due to slow changes in direct current voltages which may occur as error sources in the electronic devices.
  • Other variations may include those instances in which the sensor is not linear, or at least not perfectly linear, linearization in such instances being effected by processing the sensor signals using a microprocessor or analog circuit.
  • digital or analog circuitry may be used to provide signals that are not directly proportional to the light intensity changes from the sensor fiber. Such circuitry could be used in cases where the light variation is not sufficiently linear with deflection, or where a non-linear (for example logarithmic) response is desirable.
  • Other variations include changes in the components. For instance, there are many options for using different operational amplifiers, transistors, photo-emitters, detectors, and other components. Photo-emitters need not be of visible wavelength as those shown. Equivalent operation may be achieved with light of infrared or other wavelengths.
  • air valve system 182 is disposed between a typical air reservoir 184 and air spring 186 which extends between the frame 120 and wheel system 160.
  • the electronic measuring system 170 controls air valve system 182 through electronic control module 180 in- a known manner such that any deviation of the distance between the frame 120 and wheel system 160, relative to a desired value, will cause air to be supplied to or released from the air spring 186 in a known manner to raise or lower the frame 120 relative to the wheel system 160, back to the desired height.
  • the electronic measuring system 170 may be coupled to a display 188 which is directed by the electronic measuring system 170 to display the degree of displacement.
  • both leads of the sensor fiber pass from the electronics enclosure to the metal strip from the same end of the strip.
  • the substrate which is too flexible to be robust, is attached by means of tape or adhesive to another, thicker, metal strip, typically 0.86 to 1.0 mm thick, and of the same size as the substrate.
  • These strips are pushed into a rubber hose, of inside diameter typically 9.5 mm. Together, these strips, and the hose, are formed into an arch by bolting them through holes at the ends of the strips to the appropriate parts of the suspension.
  • the hose is chosen to have a stiffness in bending considerably less than that of the metal parts, so that the structural properties of the arch are formed primarily by the metal parts.
  • the arch is formed so that the treated side of the fiber faces out (it is convex outward), so that the intensity of light passing through the fiber decreases with increasing curvature of the arch.
  • Figure 26 represents the light intensity signal from a BEF sensor as described above having an arch length of 30 mm, attached to a fixture as sketched below the graph.
  • the sensor arch covers approximately 180 degrees of a circle near the mid-point of the angular deflections of the fixture.
  • the short line S on the arch indicates that the treated section of the fiber is attached near the mid point of the arch.
  • the fixture allows for angular movement of the lower arm (for, example, a lower control arm for the right front wheel of an automobile) . All other portions of the fixture are in a common fixed physical reference frame.
  • the x axis of the graph shows the angle of the lower arm where 20 degrees represents its horizontal position, zero degrees is its fully raised position, and 40 degrees is its fully lowered position.
  • the distance between the mounting holes of the sensor arch is approximately 10 cm.
  • the mounting holes are approximately 21.5 cm from the pivot point of the lower arm.
  • the attachment of the arch is such that, for angular excursions of the lower arm. the arch undergoes a combination of angular and linear deflections of its "arms" (the relatively straight sections near the attachment points), such that the attachment points nearly touch when the lower arm is raised to 0 degrees, and the arch is nearly stretched as far as possible at 40 degrees.
  • the graph expresses the output of the sensor as a percentage throughput, where 100 percent is the intensity of light when the arch has the greatest curvature.
  • Figure 27 represents the output of a different sensor attached to the same fixture as used in Figure 26.
  • the sensor is an arch 150 mm long (arch length) and describes an arc that is approximately 90 degrees of a circle when the lower arm is horizontal.
  • the short line S in the sketch below the graph indicates that the treated zone of the fiber is attached to the arch near its mid point.
  • the sketch below the graph indicates the approximate dimensions of the arch when the lower arm is horizontal.
  • the upper arm of the arch is attached to a vertical fixed portion of the fixture somewhat to the left of the pivot point of the lower arm (many different mounting points will work) . Mounting points are selected that provide the maximum linear range for the sensor.
  • the vertical and horizontal coordinates may be adjusted as desired for mounting, as well as the angle of attachment.
  • the horizontal arm of the arch is attached to the lower arm at a point approximately 7.8 cm from the pivot point, and approximately along a radius extending out from the pivot point.
  • the arms of the arch undergo predominantly angular deflections, with a minimum change in the distance between its attachment points.
  • Figure 28 is similar to Figure 26, except that a wooden hinged fixture is used to deflect the same sensor.
  • the attachment point is 24.5 cm instead of 21.5 cm, and the x axis is the linear distance between the two mounting points. Again, the output is linear.
  • Figure 29 represents three sets of data points for a similar sensor (30 cm long, but without a rubber hose, the hose not being relevant, and without a turnaround which also is not relevant).
  • the treated side of the fiber was mounted facing inward, so that light intensity increases as the curvature of the arch increases. This also is irrelevant, because in all examples the sensor fiber is being operated in its linear regions.
  • the fixture in this case is a linear stage, so that no angular deflections are being applied to the arch other than fixed angular deflections resulting from mounting the arms of the arch on metal blocks with different fixed slopes.
  • the blocks were attached to the horizontally-moving parts of the stage. Three attachment angles were used: perpendicular (vertical - see sketch for data points "- 1 -"); 26 degrees from vertical inward (see sketch for "A" data points); and 26 degrees outward (see sketch for "B" data points).
  • Suspension sensors of the present invention provide various advantages relative to prior art sensors.
  • the suspension sensor of the present invention is not mechanically complex. With the exception of the bending or flexing elements, no moving parts are required. Regardless of the degree of simplicity of the apparatus, it achieves desirable reliability, it being possible to measure angles or displacements or both in a monotonic, linear fashion.
  • the suspension sensor of the present invention is not adversely affected by the operational environment. Since it relies upon an optical system with all of the light contained in an optical fiber it is immune to external influences such as water, dirt, etc., and does not require a sealing means. An additional benefit of such an optical system is that since the measurement of displacement is an optical one based upon changes in intensity of light, there is virtually no limit on the speed of response of the system.
  • the sensor may be placed in a completely sealed environment such as a rubber hose or corrugated pipe, thereby protecting the sensor from damage due to any impact.
  • the suspension sensor of the present invention is low in cost and easy to manufacture and install. In addition, such a sensor will not normally require maintenance or replacement for long time and travel periods. In considering the geometry of the suspension sensor of the present invention, there are several features which are noteworthy. For example, it will be apparent to those skilled in the art that for most displacements of the sensor due to extraneous forces or torques, the sensor readings will be minimally affected. In addition, the arch form of the sensor is amenable to placement near pivot points such that it is protected from impact by the parts to which it is attached. The measurement of suspension deflection may be made near the pivot point of the suspension parts so that the sensor need undergo minimal or zero linear deflection. In addition, for any given mounting location, the sensor may be mounted in several different ways that can affect its linear range.

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Abstract

L'invention concerne un capteur (100) pour une suspension sous la forme d'un détecteur à fibre optique de flexion et de position (110), qui est monté sur un longeron flexible (102) lequel est fixé à ses extrémités (124, 128) à des points de référence (120, 122) de position du cadre et/ou châssis et des roues du véhicule. Le capteur de la suspension est utilisé pour détecter et/ou commander le déplacement du système de suspension d'un véhicule, tel qu'une automobile.
PCT/US1994/003141 1993-04-15 1994-03-23 Capteur a fibre optique pour suspension de vehicule WO1994024534A1 (fr)

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US08/045,796 1993-04-15

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Cited By (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0900396A1 (fr) * 1996-04-01 1999-03-10 Keith H. Wanser Capteur a fibre optique faisant appel a la deformation d'une longueur de fibre suspendue librement
WO2001089863A3 (fr) * 2000-05-25 2002-06-13 Holland Neway Int Inc Systeme de correction de hauteur et capteur associe
US6471710B1 (en) 1999-08-13 2002-10-29 Advanced Sensor Technology, Llc Probe position sensing system and method of employment of same
EP1473482A1 (fr) * 2003-05-02 2004-11-03 Continental Aktiengesellschaft Ressort pneumatique à hauteur réglable
DE10237361B4 (de) * 2002-08-12 2007-07-19 Deutsches Zentrum für Luft- und Raumfahrt e.V. Verfahren zur Herstellung eines faseroptischen Sensors und damit hergestellter Sensor
FR2983954A1 (fr) * 2011-12-13 2013-06-14 Renault Sa Ressort avec capteur de deformation integre.
EP2842777A1 (fr) * 2013-08-30 2015-03-04 PSS Consultancy & Equipment B.V. Capteur de fibre optique pour un systéme de suspension de véhicule automobile
US9452657B1 (en) 2015-12-22 2016-09-27 Ford Global Technologies, Llc Height determination for two independently suspended wheels using a height sensor for only one wheel
US10933711B2 (en) 2019-03-22 2021-03-02 Ford Global Technologies, Llc Suspension sensor

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US4761073A (en) * 1984-08-13 1988-08-02 United Technologies Corporation Distributed, spatially resolving optical fiber strain gauge
US5044205A (en) * 1986-10-15 1991-09-03 Strabag Bau-Ag Method for monitoring deformations with light waveguides
US5097252A (en) * 1987-03-24 1992-03-17 Vpl Research Inc. Motion sensor which produces an asymmetrical signal in response to symmetrical movement
US5126558A (en) * 1990-11-14 1992-06-30 Hughes Aircraft Company Joint position detector with fiber optical microbend loop

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Publication number Priority date Publication date Assignee Title
US4761073A (en) * 1984-08-13 1988-08-02 United Technologies Corporation Distributed, spatially resolving optical fiber strain gauge
US5044205A (en) * 1986-10-15 1991-09-03 Strabag Bau-Ag Method for monitoring deformations with light waveguides
US5097252A (en) * 1987-03-24 1992-03-17 Vpl Research Inc. Motion sensor which produces an asymmetrical signal in response to symmetrical movement
US5126558A (en) * 1990-11-14 1992-06-30 Hughes Aircraft Company Joint position detector with fiber optical microbend loop

Cited By (17)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0900396A4 (fr) * 1996-04-01 2000-07-19 Keith H Wanser Capteur a fibre optique faisant appel a la deformation d'une longueur de fibre suspendue librement
EP0900396A1 (fr) * 1996-04-01 1999-03-10 Keith H. Wanser Capteur a fibre optique faisant appel a la deformation d'une longueur de fibre suspendue librement
US6471710B1 (en) 1999-08-13 2002-10-29 Advanced Sensor Technology, Llc Probe position sensing system and method of employment of same
US7306239B2 (en) 2000-05-25 2007-12-11 Haldex Brake Corporation Height control system and sensor therefor
JP2004511379A (ja) * 2000-05-25 2004-04-15 ザ　ホランド　グループ，インコーポレイテッド 高さ制御システムおよびそのためのセンサ
US6991239B2 (en) 2000-05-25 2006-01-31 Haldex Brake Corporation Height control system and sensor therefor
WO2001089863A3 (fr) * 2000-05-25 2002-06-13 Holland Neway Int Inc Systeme de correction de hauteur et capteur associe
CN100376415C (zh) * 2000-05-25 2008-03-26 霍兰集团公司 高度控制系统及其传感器
DE10237361B4 (de) * 2002-08-12 2007-07-19 Deutsches Zentrum für Luft- und Raumfahrt e.V. Verfahren zur Herstellung eines faseroptischen Sensors und damit hergestellter Sensor
EP1473482A1 (fr) * 2003-05-02 2004-11-03 Continental Aktiengesellschaft Ressort pneumatique à hauteur réglable
FR2983954A1 (fr) * 2011-12-13 2013-06-14 Renault Sa Ressort avec capteur de deformation integre.
WO2013087580A1 (fr) * 2011-12-13 2013-06-20 Renault S.A.S. Ressort avec capteur de deformation integre
US9352629B2 (en) 2011-12-13 2016-05-31 Renault S.A.S. Spring having a built-in deformation sensor
EP2842777A1 (fr) * 2013-08-30 2015-03-04 PSS Consultancy & Equipment B.V. Capteur de fibre optique pour un systéme de suspension de véhicule automobile
WO2015028266A1 (fr) * 2013-08-30 2015-03-05 Pss Consultancy & Equipment B.V. Véhicule et suspension de véhicule
US9452657B1 (en) 2015-12-22 2016-09-27 Ford Global Technologies, Llc Height determination for two independently suspended wheels using a height sensor for only one wheel
US10933711B2 (en) 2019-03-22 2021-03-02 Ford Global Technologies, Llc Suspension sensor

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