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WO2025198473A1 - Dispositif de mesure de déplacement ou de contrainte - Google Patents

Dispositif de mesure de déplacement ou de contrainte

Info

Publication number
WO2025198473A1
WO2025198473A1 PCT/NL2025/050140 NL2025050140W WO2025198473A1 WO 2025198473 A1 WO2025198473 A1 WO 2025198473A1 NL 2025050140 W NL2025050140 W NL 2025050140W WO 2025198473 A1 WO2025198473 A1 WO 2025198473A1
Authority
WO
WIPO (PCT)
Prior art keywords
connection
measurement
displacement member
displacement
connection region
Prior art date
Legal status (The legal status 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 status listed.)
Pending
Application number
PCT/NL2025/050140
Other languages
English (en)
Inventor
Marinus Jacobus Van Der Hoek
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Compass Europe Group BV
Original Assignee
Compass Europe Group BV
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 Compass Europe Group BV filed Critical Compass Europe Group BV
Publication of WO2025198473A1 publication Critical patent/WO2025198473A1/fr
Pending legal-status Critical Current
Anticipated expiration legal-status Critical

Links

Classifications

    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01L—MEASURING FORCE, STRESS, TORQUE, WORK, MECHANICAL POWER, MECHANICAL EFFICIENCY, OR FLUID PRESSURE
    • G01L1/00—Measuring force or stress, in general
    • G01L1/20—Measuring force or stress, in general by measuring variations in ohmic resistance of solid materials or of electrically-conductive fluids; by making use of electrokinetic cells, i.e. liquid-containing cells wherein an electrical potential is produced or varied upon the application of stress
    • G01L1/22—Measuring force or stress, in general by measuring variations in ohmic resistance of solid materials or of electrically-conductive fluids; by making use of electrokinetic cells, i.e. liquid-containing cells wherein an electrical potential is produced or varied upon the application of stress using resistance strain gauges
    • G01L1/2206—Special supports with preselected places to mount the resistance strain gauges; Mounting of supports
    • G01L1/2243—Special supports with preselected places to mount the resistance strain gauges; Mounting of supports the supports being parallelogram-shaped
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01L—MEASURING FORCE, STRESS, TORQUE, WORK, MECHANICAL POWER, MECHANICAL EFFICIENCY, OR FLUID PRESSURE
    • G01L1/00—Measuring force or stress, in general
    • G01L1/04—Measuring force or stress, in general by measuring elastic deformation of gauges, e.g. of springs
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01L—MEASURING FORCE, STRESS, TORQUE, WORK, MECHANICAL POWER, MECHANICAL EFFICIENCY, OR FLUID PRESSURE
    • G01L1/00—Measuring force or stress, in general
    • G01L1/20—Measuring force or stress, in general by measuring variations in ohmic resistance of solid materials or of electrically-conductive fluids; by making use of electrokinetic cells, i.e. liquid-containing cells wherein an electrical potential is produced or varied upon the application of stress
    • G01L1/22—Measuring force or stress, in general by measuring variations in ohmic resistance of solid materials or of electrically-conductive fluids; by making use of electrokinetic cells, i.e. liquid-containing cells wherein an electrical potential is produced or varied upon the application of stress using resistance strain gauges
    • G01L1/2206—Special supports with preselected places to mount the resistance strain gauges; Mounting of supports
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01L—MEASURING FORCE, STRESS, TORQUE, WORK, MECHANICAL POWER, MECHANICAL EFFICIENCY, OR FLUID PRESSURE
    • G01L5/00—Apparatus for, or methods of, measuring force, work, mechanical power, or torque, specially adapted for specific purposes
    • G01L5/0061—Force sensors associated with industrial machines or actuators
    • G01L5/0076—Force sensors associated with manufacturing machines
    • G01L5/0085—Force sensors adapted for insertion between cooperating machine elements, e.g. for measuring the nip force between rollers
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01L—MEASURING FORCE, STRESS, TORQUE, WORK, MECHANICAL POWER, MECHANICAL EFFICIENCY, OR FLUID PRESSURE
    • G01L5/00—Apparatus for, or methods of, measuring force, work, mechanical power, or torque, specially adapted for specific purposes
    • G01L5/0095—Apparatus for, or methods of, measuring force, work, mechanical power, or torque, specially adapted for specific purposes measuring work or mechanical power
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01L—MEASURING FORCE, STRESS, TORQUE, WORK, MECHANICAL POWER, MECHANICAL EFFICIENCY, OR FLUID PRESSURE
    • G01L5/00—Apparatus for, or methods of, measuring force, work, mechanical power, or torque, specially adapted for specific purposes
    • G01L5/13—Apparatus for, or methods of, measuring force, work, mechanical power, or torque, specially adapted for specific purposes for measuring the tractive or propulsive power of vehicles
    • G01L5/133—Apparatus for, or methods of, measuring force, work, mechanical power, or torque, specially adapted for specific purposes for measuring the tractive or propulsive power of vehicles for measuring thrust of propulsive devices, e.g. of propellers
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01L—MEASURING FORCE, STRESS, TORQUE, WORK, MECHANICAL POWER, MECHANICAL EFFICIENCY, OR FLUID PRESSURE
    • G01L5/00—Apparatus for, or methods of, measuring force, work, mechanical power, or torque, specially adapted for specific purposes
    • G01L5/16—Apparatus for, or methods of, measuring force, work, mechanical power, or torque, specially adapted for specific purposes for measuring several components of force
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01L—MEASURING FORCE, STRESS, TORQUE, WORK, MECHANICAL POWER, MECHANICAL EFFICIENCY, OR FLUID PRESSURE
    • G01L5/00—Apparatus for, or methods of, measuring force, work, mechanical power, or torque, specially adapted for specific purposes
    • G01L5/16—Apparatus for, or methods of, measuring force, work, mechanical power, or torque, specially adapted for specific purposes for measuring several components of force
    • G01L5/161—Apparatus for, or methods of, measuring force, work, mechanical power, or torque, specially adapted for specific purposes for measuring several components of force using variations in ohmic resistance
    • G01L5/1627—Apparatus for, or methods of, measuring force, work, mechanical power, or torque, specially adapted for specific purposes for measuring several components of force using variations in ohmic resistance of strain gauges
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01L—MEASURING FORCE, STRESS, TORQUE, WORK, MECHANICAL POWER, MECHANICAL EFFICIENCY, OR FLUID PRESSURE
    • G01L5/00—Apparatus for, or methods of, measuring force, work, mechanical power, or torque, specially adapted for specific purposes
    • G01L5/16—Apparatus for, or methods of, measuring force, work, mechanical power, or torque, specially adapted for specific purposes for measuring several components of force
    • G01L5/166—Apparatus for, or methods of, measuring force, work, mechanical power, or torque, specially adapted for specific purposes for measuring several components of force using photoelectric means

Definitions

  • the present invention relates to a device for measuring displacement or strain, in particular for measuring extremely small phenomena, such as displacement or deformation of relatively rigid measurement objects.
  • US 3.438.251 A discloses a transducer which can be used either to measure displacement or to measure force, the former if the transducer resists motion with a negligible force, and the latter if the transducer produces a significant resisting force.
  • Readout is by optics, for example by a beam of collimated light from an autocollimator entering the transducer, traversing a prescribed path within the transducer, and being returned to the autocollimator for sensing.
  • a force transducer it may be made in combination with external or internal springs to provide greater resisting force than can be generated by full-scale deflection of the motion transducer alone.
  • “Full-scale” is determined by the maximum angle the accessory autocollimator can accommodate, or alternately, by the maximum nonlinearity per mitted between the true motion or force input and the displayed reading.
  • the transducer is in the form of a hollow square with rigid sides hinged at the corners and reflecting means on the sides are optically aligned to transmit an incident beam successively to adjacent reflecting means.
  • WO 2016/149819 A1 discloses a sensor assembly that can measure axial and lateral forces and/or axial and lateral torques acting on an instrument independent of steady state temperature variations.
  • the sensor assembly has a sensor body for coupling to the instrument such that a shaft and tip of the instrument extend from opposing ends of the sensor body.
  • the sensor body has first and second strain sensing regions.
  • the sensor assembly further includes first and second strain sensors coupled to and configured to measure axial strain of the first and second regions. When the sensor body is coupled to the instrument each of the first and second regions experience an opposite one of a tensile axial strain and a compressive axial strain in response to an axial force or an axial torque acting on the tip of the instrument.
  • EP 3.312.556 A1 discloses a transducer for assisting in measuring displacement or strain in an object of interest.
  • the transducer comprises a plate having at least two end sections for mounting the transducer to the object of interest.
  • the transducer furthermore comprises a flexible connection between the two end sections.
  • the flexible connection comprises a plurality of rigid portions and flexible interconnections between the rigid portions for allowing relative movement of the rigid portions with respect to each other.
  • the flexible connection has a central section comprising two rigid portions spaced from each other over a distance and adapted for positioning a strain sensing element at the spacing in between said two rigid portions.
  • the rigid portions and flexible interconnections are arranged so that a displacement applied to the end sections results in a relative displacement at the spacing in the central section that is larger than the relative displacement applied to the end sections.
  • Another problem with the abovementioned devices is that the devices may not be energy-neutral, i.e. the energy required for “stretching” the device may be different from the energy needed to “relax” the device.
  • An object of the present invention is thus to provide an abovementioned device for measuring displacement or strain, wherein sensitivity to differences in temperature is decreased.
  • Another object of the present invention is thus to provide an abovementioned device for measuring displacement or strain that is more “energyneutral”.
  • Yet another object of the present invention is thus to provide an abovementioned device for measuring displacement or strain, wherein out-of-plane strain is more properly dealt with.
  • Yet another object of the present invention is thus to provide an abovementioned device for measuring displacement or strain, wherein the influence of wavelength noise on the measurement results is decreased.
  • a device for measuring displacement or strain comprising: a first portion having a first connection region for connection to a first measurement part, a second portion, spaced-apart from the first portion in an axial direction along a main axis, having a second connection region for connection to a second measurement part, wherein the first portion and the second portion are configured to be displaceable relative to each other in the axial direction and/or in a lateral direction transversal to the axial direction, when, respectively, an axial force and/or a lateral force is applied to the first connection region by the first measurement part and/or the second connection region by the second measurement part, a connection portion, connecting the first portion and the second portion to each other, wherein the axial force and/or the lateral force is transferred between the first portion and the second portion by the connection portion, wherein the axial stiffness and/or the lateral stiffness of the connection portion in the axial direction and/or lateral direction is lower than an axial stiffness and/or lateral stiffness
  • the abovementioned device is capable of achieving accurate measurement of the deformation of the object by “amplification” of the effects resulting from deformation of the object and subsequent sensing of the amplified effects.
  • the device can be operated in “differential mode”, which enables compensation of the effect of temperature on thermal expansion of the transducer. Furthermore, the device is thus more “energy-neutral”, out-of-plane strain is optimally dealt with and wavelength noise on the measurement results is decreased.
  • the device is suitable for measuring displacement or strain.
  • Displacement or strain may be caused by a plurality of chemical and/or physical phenomena, which causes “actuation” of the device and thus, in turn, some form of displacement or strain exerted on the device.
  • Such displacement or strain (directly) translates into displacement of the displacement member, for instance proportional displacement, such as “1-on-1” or equal displacement, which may be measured with appropriate measurement means, such as optical sensors.
  • the device may also be used for measuring displacement or strain as a result of torque applied around the main (X-)axis or a bending moment applied around a Z-axis, i.e. an axis perpendicular to the main (X-)axis and a Y-axis aligned with the lateral direction, or a bending moment applied around the Y-axis aligned with the lateral direction.
  • stiffness is generally to be interpreted as resistance to deformation or strain due to an applied force (or torque/bending moment).
  • the expression “lateral” furthermore generally relates to a direction perpendicular to the axial direction.
  • lateral stiffness thus generally relates to “shear stiffness”.
  • US 8.186.232 B2 discloses a displacement sensor which seeks to detect displacements along a linear axis (X). Measurement errors due to unwanted displacement (and rotation) on other axes are minimized by employing a structure with "anisotropic stiffness". It should be noted that the displacement member disclosed by US 8.186.232 B2 does not extend freely from the connection region, because the displacement member is connected to the rest of the sensor by intermediate structures. The displacement member is thus involved in force transfer, in contrast to the present disclosure. Furthermore, because the displacement member is connected to the rest of the sensor by intermediate structures, tuning of the (amplification of the) sensor according to US 8.186.232 B2 is difficult, due to “interference” of the intermediate structures.
  • US 5.510.581 A discloses a flat load cell for weighing an object with two beams that, upon lateral force exertion, bend in an “S-shaped manner” in order to negate the effects of such lateral forces, so that the weighing of the object is not affected.
  • the load-receiving tongue disclosed by US 5.510.581 A again appears to be involved in force transfer, in contrast with the present disclosure.
  • US 5.510.581 A is furthermore (thus) not suitable for measuring lateral forces.
  • US 2009/100941 A1 discloses a device for measuring all kinds of “mechanical quantities”, for example by measuring a distance between two displacement members, wherein the distance varies in a non-linear manner in response to a force applied in a direction perpendicular to the displacement members. Because the distance is not proportional to the force applied, predictable and tunable “amplification” is hard to achieve with such a device.
  • An embodiment relates to an aforementioned device, wherein the displacement member extends freely from the first portion, such as from the first connection region, i.e. the displacement member is not connected to surrounding structures of the device, except for the position where the displacement member connects to the first portion, such as the first connection region.
  • the displacement member thus does not “interfere” with force transfer.
  • connection portion transfers the axial and/or lateral force between the first portion and the second portion without involving the displacement member, i.e. the connection portion essentially transfers 100% of the axial and/or lateral force between the first portion and the second portion.
  • An embodiment relates to an aforementioned device, wherein the displacement member extends along the main axis.
  • the displacement member extends along the main axis.
  • An embodiment relates to an aforementioned device, wherein the displacement member does not transfer any axial force and/or lateral force between the first connection region and the second connection region, i.e. the displacement member does not transfer any axial and/or lateral force between the first connection region and the second connection region.
  • An embodiment relates to an aforementioned device, wherein the axial stiffness and/or lateral stiffness of the connection portion comprises the lowest axial stiffness and/or lateral stiffness present between the first connection region and the second connection region.
  • the axial stiffness and/or lateral stiffness should not be so low that the connection portion itself gets damaged, as the skilled person will understand.
  • connection portion has a total force transferring cross-sectional area lower than a total force transferring cross-sectional area of the first portion and/or second portion adjacent to the connection portion.
  • connection portion will then maximally deform (provided a material is chosen for the connection portion that has an appropriate modulus of elasticity) and the device sensitivity is then most optimal.
  • An embodiment relates to an aforementioned device, wherein the total force transferring cross-sectional area of the connection portion constitutes the lowest total force transferring cross-sectional area between the first connection region and the second connection region. Analogous to the above, optimal sensitivity of the connection portion can then be obtained.
  • An embodiment relates to an aforementioned device, wherein the total force transferring cross-sectional area of the connection portion is 10 - 30%, such as 15 - 25% of the total force transferring cross-sectional area of the first portion and/or second portion adjacent to the connection portion. In practice, such a total force transferring cross-sectional area leads to sufficient deformation of the connection portion, i.e. sufficient sensitivity of the transducer, whereas the connection portion is still able to transfer significant force between the first connection region and the second connection region.
  • An embodiment relates to an aforementioned device, wherein the first and/or second portion comprises a space into which a free end of the displacement member extends, wherein one or more sensors, such as optical or electrical sensors, are arranged in the space and/or in the first and/or second portion adjacent to the space for sensing the displacement of the free end of the displacement member in the axial direction and/or the lateral direction.
  • the space can thus be conveniently used for measuring the axial and/or lateral displacements of the free end of the displacement member, by arranging the one or more sensors - in all sorts of configurations - in the area surrounding/enclosing the space.
  • An embodiment relates to an aforementioned device, wherein the displacement member has an intermediate portion connecting the free end of the displacement member to the connection portion, wherein the free end has a width in the lateral direction larger than a width of the intermediate portion.
  • the displacement member has a sort of “head” (the free end of the displacement member) suitable for measurements and a “stem” (the intermediate portion) to displace the head in the axial and lateral directions.
  • the “stem” may have a smaller width than the “head” in order to not unduly weaken the first and/or second portion through which the stem extends (and freely moves).
  • one or more sensors can thus be specifically arranged to measure the axial displacement of the head, such as on the “front side” or the “back side” of the head (when seen in the axial direction) which would otherwise be more difficult to achieve.
  • An embodiment relates to an aforementioned device, wherein the width of the free end of the displacement member is 2 - 5 times, such as 2 - 4 times, larger than the width of the intermediate portion.
  • at least one sensor can thus be arranged on one or both lateral sides of the displacement member to measure the axial displacement of the free end of the displacement member, i.e. the head without weakening the structure of the first and/or second portion.
  • An embodiment thus relates to an aforementioned device, wherein one of the sensors is arranged for sensing the displacement of the free end of the displacement member in the axial direction.
  • An embodiment relates to an aforementioned device, wherein one of the sensors is arranged for sensing the displacement of the portion of the displacement member in the lateral direction.
  • the optical sensor can also be arranged to measure the displacement of the free end of the displacement.
  • connection portion comprises one or more, such as two, three or four, connection members extending in the axial direction, wherein the one or more connection members are arranged in a symmetric manner with respect to the main axis.
  • the deformability of the connection portion can be designed and tuned in a relatively easy manner by adding or removing one or more connection members depending on the application.
  • the deformability of the connection portion is also relatively well-predictable.
  • An embodiment relates to an aforementioned device, wherein the first portion, the second portion, the connection portion, the displacement member and the one or more sensors are arranged in such a way, that the device has a plate-like shape.
  • a plate-like shape is relatively easy to connect to an object to be measured.
  • An embodiment relates to an aforementioned device, wherein the plate-like-shaped device is curved around a curvature axis parallel to the main axis.
  • the plate-like-shaped device can be attached to curved surfaces.
  • “Plate-like” in this respect is thus not to be exclusively interpreted as being “planar” (i.e. extending along a certain geometrical plane).
  • An embodiment relates to an aforementioned device, wherein the plate-like-shaped device is curved around a curvature axis parallel to the main axis, in such a way, that the plate-like-shaped device fully encloses the curvature axis, creating a ring-shaped device.
  • the plate-like-shaped device can be installed onto a tube or shaft or can even be designed to be an integral part of such a tube or shaft.
  • An embodiment relates to an aforementioned device, wherein the one or more sensors for sensing the displacement of the displacement member in the axial direction and/or the lateral direction comprise one or more optical sensors and/or one or more electrical sensors.
  • a measurement assembly comprising: a first measurement part, a second measurement part, an aforementioned device, wherein the first portion of the device is connected to the first measurement part with the first connection region, and wherein the second portion of the device, spaced-apart from the first portion in the axial direction along the main axis, is connected to the second measurement part with the second connection region.
  • US 4.079.624 A discloses a cylindrical body with opposite sensors placed to measure axial and/or torsional forces in the cylindrical body. To this end, the sensors are equipped with piezo-resistive elements that can be arranged in various ways and orientations. However, US 4.079.624 A does not in any way relate to the “strain amplification” concept underlying the present disclosure.
  • An embodiment relates to an aforementioned measurement assembly, wherein the first measurement part and the second measurement part belong to a single measurement object.
  • the single measurement object could for instance be a tube or shaft.
  • An embodiment thus relates to an aforementioned measurement assembly, wherein the first measurement part and the second measurement part have a tubular shape.
  • An embodiment relates to an aforementioned measurement assembly, wherein, in the axial direction, the first connection region is integrated with or transitions into the first measurement part and/or wherein the second connection region is integrated with or transitions into the second measurement part.
  • the device can be conveniently integrated “by design” in between the first and second measurement parts and/or in the measurement object.
  • An embodiment relates to an aforementioned measurement assembly, wherein the first measurement part and the second measurement part comprise a first wall segment and a second wall segment, respectively, of a tubular wall of a single, tubular measurement object, having a centerline, wherein the second portion, the connection portion, the displacement member and the one or more sensors are arranged in such a way, that the device has a plate-like shape, wherein the plate-like-shaped device is curved around the centerline of the tubular measurement object, wherein the first connection region is connected to an outer surface of the first wall segment and the second connection region is connected to an outer surface of the second wall segment.
  • the device can be attached conveniently to an outer surface of a curved measurement part of measurement object.
  • An embodiment relates to an aforementioned measurement assembly, wherein the first measurement part and the second measurement part comprise a first wall segment and a second wall segment, respectively, of a tubular wall of a single, tubular measurement object, having a centerline, wherein the second portion, the connection portion, the displacement member and the one or more sensors are arranged in such a way, that the device has a plate-like shape, wherein the plate-like-shaped device is curved around the centerline of the tubular measurement object, wherein, in the axial direction, the first connection region is integrated with or transitions into the first wall segment and wherein the second connection region is integrated with or transitions into the second wall segment.
  • the device can be integrated with a tubular measurement object or between first and second measurement parts.
  • An embodiment relates to an aforementioned measurement assembly, comprising a plurality of laterally connected plate-like-shaped devices, wherein the plate-like-shaped devices are curved around the centerline in such a way, that the plate-like-shaped devices fully enclose the centerline, creating a ring-shaped device forming an intermediate wall segment between the first wall segment and the second wall segment.
  • the device can between tubular first and second measurement parts. The device can thus even be retrofitted between existing tubular parts.
  • Another aspect of the invention concerns a motor assembly, comprising a motor and an aforementioned measurement assembly, wherein the motor is configured for driving the tubular measurement object around the centerline of the tubular measurement object.
  • the device can thus be advantageously used for measuring torque, thrust, et cetera, produced by the motor and exerted on the tubular measurement object (and any reaction forces or torque exerted on the tubular measurement object, for instance by a fluid, bearings, et cetera).
  • Another aspect of the invention concerns a mixing device, comprising an aforementioned motor assembly, wherein the motor is configured for driving the tubular measurement object around the centerline of the tubular measurement object for mixing a substance, wherein the tubular measurement object is arranged for transferring driving forces from the motor to the substance to be mixed.
  • a particular embodiment foreseen by the Applicant concerns a mixing device for mixing substances, such as fluids, wherein the tubular measurement object preferably comprises a shaft, preferably provided with stirring or mixing means, such as a propeller, helix, or the like, for transferring driving/mixing forces produced by the motor assembly to the substance(s) to be mixed.
  • stirring or mixing means such as a propeller, helix, or the like
  • Figure 1 shows an example embodiment of a device according to the invention
  • Figure 2 shows a close-up of the axially arranged optical sensors of Figure 1 , wherein the optical sensors are embodied by a set of reflecting mirrors;
  • Figures 3A and 3B show an example embodiment of a device according to the invention in an axially undeformed and a deformed condition, respectively;
  • Figure 4 shows a perspective view of an example embodiment of a device according to the invention, wherein the device has a plate-like shape
  • Figure 5 shows an example embodiment of a device according to the invention, serving to illustrate the effects of thermal expansion
  • Figure 6 shows an example embodiment of a device according to the invention, wherein the device is shown in a laterally deformed condition, with the optical sensors being laterally arranged;
  • Figures 7A and 7B show cross-sensitivity of laterally and axially responsive optical sensors, respectively;
  • Figures 8A and 8B show an example embodiment of a mechanical transducer for transferring forces to an optical sensor enclosed by the mechanical transducer;
  • Figure 8C shows the change in gap distance for the mechanical transducer shown in Figures 8A and 8B;
  • Figure 9 shows a graph with the mechanical amplification factor (relative displacement amplification factor) for the mechanical transducer of Figures 8A and 8B;
  • Figure 10 shows an example embodiment of a device according to the invention, comprising three abovementioned mechanical transducers (as depicted in Figures 8A and 8B);
  • Figures 11A and 11 B show an example embodiment of a measurement assembly according to the invention, comprising a first measurement part, a second measurement part, and an example embodiment of one, respectively two, devices according to the invention connecting the first measurement part and the second measurement part in the axial direction;
  • Figure 12 shows an example embodiment of a measurement assembly according to the invention, comprising a tubular measurement object and an example embodiment of a device according to the invention, having a curved, platelike shape, wherein the device is attached to an outer wall surface of the tubular measurement object;
  • Figure 13 shows an example embodiment of a measurement assembly according to the invention, comprising a tubular measurement object and example embodiments of a plurality of laterally connected plate-like-shaped devices according to the invention, forming a ring-shape, with the device being curved around the centerline of the tubular measurement object, wherein the ring-shaped device is integrated with or transitions into wall segments of the tubular measurement object in the axial direction;
  • Figure 14 shows an example embodiment of a mixing device according to the invention.
  • Figures 15a-15c show example embodiments of a connection member according to the invention.
  • Figure 1 shows an example embodiment of a device 1 according to the invention.
  • a device 1 for measuring displacement, deformation or strain is shown.
  • the device 1 as shown comprises a first portion 2 having a first connection region 3 for connection to a first measurement part 4.
  • the device 1 also comprises a second portion 5, spaced-apart from the first portion 2 in an axial direction (X) along a main axis X, having a second connection region 6 for connection to a second measurement part 7.
  • the first connection region 3 and the second connection region 6 may provide connection or attachment to the first measurement part 4 and the second measurement part 7, respectively, by means of bolting, screwing, clamping, welding, gluing or any other suitable connection means.
  • ball bearings could also be used.
  • the first portion 2 and the second portion 5 are configured to be displaceable or deformable relative to each other in the axial direction X and/or in a lateral direction Y transversal to the axial direction X, when, respectively, an axial force and/or a lateral force is applied to the first connection region 3 by the first measurement part 4 and/or the second connection region 6 by the second measurement part 7.
  • Figure 1 shows a measurement assembly 17, comprising a first measurement part 4, a second measurement part 7 and the aforementioned device 1 , wherein the first portion 2 of the device 1 is connected to the first measurement part 4 with the first connection region 3, and wherein the second portion 5 of the device 1 , spaced-apart from the first portion 2 in the axial direction along the main axis X, is connected to the second measurement part 7 with the second connection region 6.
  • the device 1 may be embodied by a monolithic body or element.
  • the device 1 also comprises a connection portion 8, connecting the first portion 2 and the second portion 5 to each other.
  • the axial force and/or the lateral force is transferred between the first portion 2 and the second portion 5 by the connection portion 8.
  • the axial stiffness and/or the lateral stiffness of the connection portion 8 in the axial direction X and/or lateral direction Y is lower than an axial stiffness and/or lateral stiffness of the first portion 2 and/or second portion 5 adjacent to the connection portion 8.
  • the connection portion 8 is symmetric with respect to the main axis X.
  • the device 1 furthermore comprises a displacement member 9 connected to the first portion 2 and/or second portion 5.
  • the displacement member 9 is displaceable along with the first portion 2 and/or second portion 5.
  • the displacement member 9 as shown in Figure 1 is connected to the first portion 2.
  • the displacement member 9 does not transfer any axial force and/or lateral force between the first portion 2 and the second portion 5.
  • the device 1 moreover comprises one or more optical sensors 10, 10A, 10B, 10C, 10D for sensing the displacement of the displacement member 9 in the axial direction X and/or the lateral direction Y.
  • optical sensors 10A, 10B, 10C, 10D for sensing the displacement of the displacement member 9 in the axial direction X and/or the lateral direction Y.
  • electrical sensors may also be used, provided the device 1 is carefully designed.
  • the axial stiffness and/or lateral stiffness of the connection portion 8 comprises the lowest axial stiffness and/or lateral stiffness present between the first connection region 3 and the second connection region 6.
  • the first portion 2 and/or second portion 5 comprises a space 11 into which a free end 12 of the displacement member 9 extends.
  • the one or more optical sensors 10, 10A, 10B, 10C, 10D are arranged in the space
  • the one or more optical sensors 10 to detect the parameter(s) of interest may be arranged or attached at various locations in or around the space 11 , as depicted in Figure 1 .
  • the displacement member 9 as shown in Figure 1 has an intermediate portion 13 connecting the free end 12 of the displacement member 9 to the connection portion 8.
  • the free end has a width W12 in the lateral direction Y larger than a width W13 of the intermediate portion 13.
  • the width W12 of the free end 12 of the displacement member 9 may be 2 - 5 times, such as 2 - 4 times, larger than the width W13 of the intermediate portion 13.
  • optical sensors 10A and 10B of the example embodiment of the device as shown in Figure 1 are arranged for sensing the displacement of the free end
  • optical sensors 10 are arranged for sensing the displacement of the intermediate portion 13 of the displacement member 9 in the lateral direction Y.
  • the one or more optical sensors 10 may comprise an optical fiber 32, for instance routed along locations of interest as shown in Figure 1 , as well as fiber fixation (points) 33 for fixing the optical fiber 32 in or around the space 11 , and furthermore one or more (optical) sensing elements 31 , such as Fiber Bragg Gratings (FBG’s).
  • FBG Fiber Bragg Gratings
  • connection portion 8 preferably comprises one or more, such as two (as shown in Figure 1), three or four, connection members 14 extending in the axial direction X.
  • the one or more connection members 14 are arranged in a symmetric manner with respect to the main axis X.
  • the device 1 can be from metal or non-metal, like ceramics, as to construct an all “dielectric” device 1.
  • Figure 2 shows a close-up of the axially arranged optical sensors 10 of Figure 1 , although the optical sensors 10 are now embodied by a set of reflecting mirrors 34 (connected to an optical fiber 32) to measure the deformation of the device 1 , like e.g. with an interferometric- or wavelength-modulated technique.
  • the set of reflecting mirrors 34 are plan-parallel and may operate in e.g. interferometry mode.
  • Figures 3A and 3B show an example embodiment of a device 1 according to the invention, such as the embodiment of Figure 1 , in an axially undeformed and a deformed condition, respectively.
  • Figure 3B shows the (planar) device 1 in deformed condition, resulting from e.g. an external force or displacement of the first and/or second connection regions (see e.g. Figure 1).
  • the connection portion 8 and the connection members 14 may be designed to have much smaller lateral dimensions than any other part of the device 1 , the deformation as shown will result from deformation of the connection members 14. Note the equivalence of the variation AL at various locations of the device 1 (by design).
  • Characteristic for the invention is that, given a rigid coupling between the object and the first connection region 3 and second connection region 6 of the device 1 and a (designed-in) low stiffness of the connection portion 8, the change in distance Li between the first and second connection regions of the device 1 , denoted by AL, is transferred via the displacement member 9 - with the displacement member 9 by design not being deformed by the deformation of the measurement object - to a change in distance L2.
  • AL the relative displacement over a gap denoted by £, is given by:
  • the relative displacement (‘strain’), £1, of the measurement object is converted into a relative displacement denoted by £ with an amplification factor given by Li I L2.
  • the mechanical amplification factor can be adjusted to the desired sensitivity of the device 1.
  • the displacement in the axial direction X, AL can be measured using a suitable optical sensor 10, which can be of various constructions and based on a multitude of operating principles.
  • a fiber-optic based sensor is the Fiber Bragg Grating (FBG), but other sensing mechanisms can be applied as well.
  • contactless sensing techniques like interferometry using a set of plan parallel mirrors as depicted in Figure 2 can be used. Careful design of the device 1 allows the use of electrical sensors, such as capacitive transducers or alike.
  • the indicated deformation of the device 1 e.g. results in signals for the optical sensors 10 shown in the lower right part of the space 11 , i.e. optical sensors 10A and 10B, as shown in Figure 1 having an equal amplitude, but opposite sign.
  • pretensioning of the optical fibers 32 is required to achieve an operating range spanning a decrease in distance L2 as well. In that case, during assembly of the optical sensors 10, pre-tensioning of the optical fibers 32 of the optical sensors 10 will be at the same level.
  • optical fiber-based sensors 10 are used as depicted in Figure 1 , conservation of symmetry in in-plane lateral forces acting on the displacement member 9 can be “balanced” even more by attachment of optical fibers 32 at the locations shown in Figure 1. These optical fibers 32 are to be stretched to the same amount as the optical fibers 32 actually involved in “sensing” in order to balance out pre-tensioning forces even further, or to increase the resonance frequency of the displacement member 9.
  • the described device 1 geometry can be used as a “stand-alone” element, mounted to an object of which the effects are to measured, or the device 1 geometry can be directly machined into the material (like a wall) of an object of which properties of interest are to be monitored (see e.g. Figure 13).
  • Figure 4 shows a perspective view of an example embodiment of a device 1 according to the invention, such as the embodiment of Figure 1 , wherein the device 1 has a plate-like shape 15. More specifically, the first portion 2, the second portion 5, the connection portion 8, the displacement member 9 and the one or more optical sensors 10 (not shown for sake of clarity) are arranged in such a way, that the device 1 has a plate-like shape 15, i.e. having a relatively large length and width (in the X and Y directions) compared to a thickness of the device 1 (i.e. perpendicular to X and Y directions), for instance a thickness of 1 - 5% of a length in the X direction or 1 - 5% of a width in the Y directions.
  • connection portion 8 as shown in Figure 4 has a total force transferring cross-sectional area As lower than a total force transferring cross- sectional area A2, As of the first portion 2 and/or second portion 5 adjacent to the connection portion 8.
  • the total force transferring cross-sectional area As of the connection portion 8 constitutes the lowest total force transferring cross-sectional area between the first connection region 3 and the second connection region 6.
  • the total force transferring cross-sectional area As of the connection portion 8 is 10 - 30%, such as 15 - 25% of the total force transferring cross-sectional area A2, As of the first portion 2 and/or second portion 5 adjacent to the connection portion 8.
  • Figure 5 shows an example embodiment of a device 1 according to the invention, serving to illustrate the effects of thermal expansion.
  • optical sensor 10A and 10B as depicted in the lower right part of the space 11 in Figure 1 , and (axial) reference points A, B, C and D as shown Figure 5, optical sensor 10A will respond to the difference in distance BA, while optical sensor 10B will respond to a change in distance DC.
  • R as a reference point, the temperature-induced displacement of point A (AA) amounts to:
  • ADC L2 . a .
  • AT Thermal expansion of the device 1 therefore results in an equal change of the distance L2 at the locations of optical sensor 10A and 10B.
  • the difference between optical sensor 10A and 10B is therefore insensitive to temperature.
  • Figure 6 shows an example embodiment of a device 1 according to the invention, wherein the device 1 is shown in a laterally deformed condition, with the optical sensors 10 being laterally arranged (i.e. laterally extending). Sensing of lateral movements of the first portion 2 of the device 1 is depicted in Figure 6 and can be measured using the laterally arranged optical sensors 10.
  • the optical sensors 10 again operate as a set of sensors with an identical response in amplitude but with opposite sign.
  • Figures 7A and 7B show cross-sensitivity of laterally (R y ) and axially responsive (R x ) optical sensors 10, respectively.
  • the cross-sensitivity response R x will be the same for optical sensors 10C and 10D.
  • the cross-sensitivity S cancels out in the result, as illustrated by the following example:
  • Figures 8A and 8B show an example embodiment of a mechanical transducer 36 for transferring forces to an optical sensor 10 enclosed by the mechanical transducer 36. If an amplification factor (say: A1) is not sufficient to achieve the required sensitivity or required signal to noise ratio, a concept of an alternative construction of a mechanical amplifier 36 is shown in Figures 8A and 8B, depicting a preferably monolithic planar object consisting of rigid elements 38 connected by elastic hinges 39. According to Figure 8C, the change in gap distance G of the “diamondshaped” transducer 36, denoted by AG, is given by:
  • Ax (-y / x) .
  • AL can be expressed by:
  • AL EO. L, In which £ 0 represents the variation in strain of the object to which the diamond structure is mounted to.
  • strain amplification (A) is given by:
  • the mechanical amplification factor can be written as:
  • a m represents the relative displacement of the transducer 36 with respect to the relative displacement of the object.
  • Figure 9 shows a graph with the mechanical amplification factor (relative displacement amplification factor) for the mechanical transducer 36 of Figures 8A and 8B.
  • Figure 10 shows an example embodiment of a device 1 according to the invention, comprising three abovementioned mechanical transducers 32 (as depicted in Figures 8A and 8B), wherein one of the mechanical transducers 36 is axially arranged and two of the mechanical transducers 36 are laterally arranged.
  • Figures 11A and 11 B show an example embodiment of a measurement assembly 17 according to the invention, comprising a first measurement part 4, a second measurement part 7, and an example embodiment of one, respectively two, devices 1 according to the invention connecting the first measurement part 4 and the second measurement part 7 in the axial direction X.
  • Figures 11 A and 11 B serve to illustrate that sensing can be done in multiple dimensions.
  • the devices 1 are shown as a rectangular element mounted to the measurement parts 4, 7. However, the device 1 can have various (sensing) geometries to optimize the response to the parameters of interest (e.g. the design shown in Figure 1).
  • Figure 12 shows an example embodiment of a measurement assembly 17 according to the invention, comprising a tubular measurement object 23 and an example embodiment of a device 1 according to the invention, having a curved, plate-like shape 15.
  • the device 1 is attached to an outer wall surface 24, 25 of the tubular measurement object 23.
  • Figure 12 more in particular shows that the first measurement part 4 and the second measurement part 7 belong to a single measurement object 18.
  • the first measurement part 4 and the second measurement part 7 have a tubular shape 19.
  • the first measurement part 4 and the second measurement part 7 comprise a first wall segment 20 and a second wall segment 21 , respectively, of a tubular wall 22 of a single, tubular measurement object 23, having a centerline C.
  • the second portion 5, the connection portion 8, the displacement member 9 and the one or more optical sensors 10 are arranged in such a way, that the device 1 has a plate-like shape 15, wherein the plate-like-shaped device 15 is curved around the centerline C of the tubular measurement object 23.
  • the first connection region 3 is connected to an outer surface 24 of the first wall segment 20 and the second connection region 6 is connected to an outer surface 25 of the second wall segment 21.
  • the device 1 can thus be advantageously used to measure torsional forces/deformations as well as axial forces/deformations. Instead of attaching the plate-like-shaped device 1 to the outer wall surfaces 24, 25 the device 1 could also be machined/milled into the tubular wall 22.
  • Figure 13 shows an example embodiment of a measurement assembly 17 according to the invention, comprising a tubular measurement object 23 and example embodiments of a plurality of laterally connected plate-like-shaped devices 1 , 15 according to the invention, forming a ring-shape 16, with the devices 1 , 15 being curved around the centerline C of the tubular measurement object 23.
  • the ring-shaped device 16 is integrated with or transitions into wall segments 20, 21 of the tubular measurement object 23 in the axial direction X, i.e. in the axial direction X, the first connection region 3 is integrated with or transitions into the first measurement part 4 and/or the second connection region 6 is integrated with or transitions into the second measurement part 7.
  • the first measurement part 4 and the second measurement part 7 comprise a first wall segment 20 and a second wall segment 21 , respectively, of a tubular wall 22 of a single, tubular measurement object 23, having a centerline C.
  • the second portion 5, the connection portion 8, the displacement member 9 and the one or more optical sensors 10 are arranged in such a way, that the device 1 has a plate-like shape 15, wherein the plate-like-shaped device is curved around the centerline C of the tubular measurement object 23, wherein, in the axial direction X, the first connection region 3 is integrated with or transitions into the first wall segment 20 and wherein the second connection region 6 is integrated with or transitions into the second wall segment 21.
  • the measurement assembly 17 comprises a plurality of laterally connected plate-like-shaped devices 1 , 15, wherein the plate-like-shaped devices 15 are curved around the centerline C in such a way, that the plate-like-shaped devices 15 fully enclose the centerline C, creating a ring-shaped device 16 forming an intermediate wall segment 26 between the first wall segment 20 and the second wall segment 21.
  • One of the optical sensors 10 may be axially arranged to measure “thrust”, while another optical sensor 10 may be laterally arranged to measure “torque”.
  • FIG 14 shows an example embodiment of a mixing device 29 according to the invention.
  • the mixing device 29 comprises a motor assembly 27, comprising a motor 28 and an aforementioned measurement assembly 17.
  • the motor 28 is configured for driving the tubular measurement object 23 around the centerline C of the tubular measurement object 23 for mixing a substance 30.
  • the tubular measurement object 23 is thus arranged for transferring driving forces from the motor 28 to the substance 30 to be mixed.
  • the optical fibers 32 are to be pre-stressed as to allow positive and negative variations in AL. Therefore, the optical fibers 32 act as a pre-tensioned ‘spring’.
  • E p the potential energy stored in a spring, elongated over a length x is given by:
  • the pre-strain, £ 0 , and unstrained length, Lo are equal.
  • the length between the fixation points 33 is set equal for both optical fibers 32.
  • the spring constant, k is equal for a set of differentially operated optical fibers 32.
  • Figures 15a - 15c show example embodiments of a connection member 14 according to the invention.
  • Figure 15a shows a relatively straightforward embodiment of the connection member 14, i.e. a connection member 14 having a constant cross-section.
  • Figure 15b shown a connection member 14 having a curved shape.
  • Figure 15c shows a connection member 14 having a decreasing/increasing cross-section (like an hourglass).
  • pairs of such connection members 14 are to be arranged in a symmetrical fashion with respect to the main (X-)axis.
  • the connection member 14 may even e.g. comprise one or more piezo elements - or such piezo elements may be arranged separately between the first portion 2 and the second portion 5.
  • connection portion As. Total force transferring cross-sectional area of connection portion

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  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Chemical & Material Sciences (AREA)
  • Analytical Chemistry (AREA)
  • Engineering & Computer Science (AREA)
  • Combustion & Propulsion (AREA)
  • Ocean & Marine Engineering (AREA)
  • Length Measuring Devices With Unspecified Measuring Means (AREA)
  • Measurement Of Length, Angles, Or The Like Using Electric Or Magnetic Means (AREA)
  • Length Measuring Devices By Optical Means (AREA)

Abstract

L'invention concerne un dispositif (1) permettant de mesurer un déplacement ou une contrainte, comprenant : une première partie (2) présentant une première région de raccordement (3) à une première partie de mesure (4), une seconde partie (5), espacée de la première partie dans une direction axiale (X) le long d'un axe principal (X), présentant une seconde région de raccordement (6) à une seconde partie de mesure (7), une partie de raccordement (8), reliant la première partie et la seconde partie, la force étant transférée entre la première partie et la seconde partie par la partie de raccordement, un élément de déplacement (9) raccordé à la première partie, l'élément de déplacement ne transférant aucune force entre elles, et un ou plusieurs capteurs (10) pour détecter le déplacement de l'élément de déplacement dans la direction axiale et/ou la direction latérale.
PCT/NL2025/050140 2024-03-21 2025-03-21 Dispositif de mesure de déplacement ou de contrainte Pending WO2025198473A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
NL2037310 2024-03-21
NL2037310A NL2037310B1 (en) 2024-03-21 2024-03-21 Device for measuring displacement or strain

Publications (1)

Publication Number Publication Date
WO2025198473A1 true WO2025198473A1 (fr) 2025-09-25

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Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3438251A (en) 1965-07-26 1969-04-15 Lord Corp Optical transducer
US4079624A (en) 1976-12-29 1978-03-21 Kulite Semiconductor Products, Inc. Load washer transducer assembly
US5510581A (en) 1994-05-18 1996-04-23 Angel; Shlomo Mass-produced flat multiple-beam load cell and scales incorporating it
US6817255B2 (en) * 2001-09-12 2004-11-16 The Board Of Trustees Of The University Of Illinois Apparatus and method for testing of microscale to nanoscale thin films
US20090100941A1 (en) 2007-09-17 2009-04-23 Andreas Scheidl Device for measuring mechanical quantities, method for measuring mechanical quantities and use of a device for measuring mechanical quantities
US8186232B2 (en) 2006-05-30 2012-05-29 The Timken Company Displacement sensor
WO2016149819A1 (fr) 2015-03-23 2016-09-29 Janabi-Sharifi Farrokh Ensembles capteurs de force et de couple insensibles aux variations de température
EP3312556A1 (fr) 2016-10-23 2018-04-25 Vrije Universiteit Brussel Transducteur d'amplification de contrainte mécanique

Patent Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3438251A (en) 1965-07-26 1969-04-15 Lord Corp Optical transducer
US4079624A (en) 1976-12-29 1978-03-21 Kulite Semiconductor Products, Inc. Load washer transducer assembly
US5510581A (en) 1994-05-18 1996-04-23 Angel; Shlomo Mass-produced flat multiple-beam load cell and scales incorporating it
US6817255B2 (en) * 2001-09-12 2004-11-16 The Board Of Trustees Of The University Of Illinois Apparatus and method for testing of microscale to nanoscale thin films
US8186232B2 (en) 2006-05-30 2012-05-29 The Timken Company Displacement sensor
US20090100941A1 (en) 2007-09-17 2009-04-23 Andreas Scheidl Device for measuring mechanical quantities, method for measuring mechanical quantities and use of a device for measuring mechanical quantities
WO2016149819A1 (fr) 2015-03-23 2016-09-29 Janabi-Sharifi Farrokh Ensembles capteurs de force et de couple insensibles aux variations de température
EP3312556A1 (fr) 2016-10-23 2018-04-25 Vrije Universiteit Brussel Transducteur d'amplification de contrainte mécanique

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