EP0527135A1 - Method and apparatus for structural actuation and sensing in a desired direction - Google Patents
Method and apparatus for structural actuation and sensing in a desired directionInfo
- Publication number
- EP0527135A1 EP0527135A1 EP91904828A EP91904828A EP0527135A1 EP 0527135 A1 EP0527135 A1 EP 0527135A1 EP 91904828 A EP91904828 A EP 91904828A EP 91904828 A EP91904828 A EP 91904828A EP 0527135 A1 EP0527135 A1 EP 0527135A1
- Authority
- EP
- European Patent Office
- Prior art keywords
- actuator
- sensor element
- substrate
- attaching
- sensor
- 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.)
- Withdrawn
Links
- 238000000034 method Methods 0.000 title claims abstract description 25
- 239000000758 substrate Substances 0.000 claims abstract description 97
- 229910001285 shape-memory alloy Inorganic materials 0.000 claims abstract description 14
- 239000007767 bonding agent Substances 0.000 claims description 15
- 239000000463 material Substances 0.000 claims description 11
- 230000003213 activating effect Effects 0.000 abstract 1
- 239000013078 crystal Substances 0.000 description 15
- 238000005452 bending Methods 0.000 description 10
- 230000008878 coupling Effects 0.000 description 5
- 238000010168 coupling process Methods 0.000 description 5
- 238000005859 coupling reaction Methods 0.000 description 5
- 238000006073 displacement reaction Methods 0.000 description 4
- 239000011159 matrix material Substances 0.000 description 4
- 230000009467 reduction Effects 0.000 description 4
- 230000001629 suppression Effects 0.000 description 4
- 230000006399 behavior Effects 0.000 description 3
- 239000002131 composite material Substances 0.000 description 3
- 230000006870 function Effects 0.000 description 3
- 230000009471 action Effects 0.000 description 2
- 229910052782 aluminium Inorganic materials 0.000 description 2
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 description 2
- 238000013459 approach Methods 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical class [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 1
- 239000004593 Epoxy Substances 0.000 description 1
- 230000001133 acceleration Effects 0.000 description 1
- 238000004458 analytical method Methods 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 230000001419 dependent effect Effects 0.000 description 1
- 238000001514 detection method Methods 0.000 description 1
- 238000011161 development Methods 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 230000001939 inductive effect Effects 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 238000005259 measurement Methods 0.000 description 1
- 229910052751 metal Inorganic materials 0.000 description 1
- 239000002184 metal Substances 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 230000010355 oscillation Effects 0.000 description 1
- 230000008685 targeting Effects 0.000 description 1
- 238000012546 transfer Methods 0.000 description 1
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01P—MEASURING LINEAR OR ANGULAR SPEED, ACCELERATION, DECELERATION, OR SHOCK; INDICATING PRESENCE, ABSENCE, OR DIRECTION, OF MOVEMENT
- G01P15/00—Measuring acceleration; Measuring deceleration; Measuring shock, i.e. sudden change of acceleration
- G01P15/02—Measuring acceleration; Measuring deceleration; Measuring shock, i.e. sudden change of acceleration by making use of inertia forces using solid seismic masses
- G01P15/08—Measuring acceleration; Measuring deceleration; Measuring shock, i.e. sudden change of acceleration by making use of inertia forces using solid seismic masses with conversion into electric or magnetic values
- G01P15/09—Measuring acceleration; Measuring deceleration; Measuring shock, i.e. sudden change of acceleration by making use of inertia forces using solid seismic masses with conversion into electric or magnetic values by piezoelectric pick-up
- G01P15/0922—Measuring acceleration; Measuring deceleration; Measuring shock, i.e. sudden change of acceleration by making use of inertia forces using solid seismic masses with conversion into electric or magnetic values by piezoelectric pick-up of the bending or flexing mode type
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B64—AIRCRAFT; AVIATION; COSMONAUTICS
- B64C—AEROPLANES; HELICOPTERS
- B64C27/00—Rotorcraft; Rotors peculiar thereto
- B64C27/001—Vibration damping devices
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01B—MEASURING LENGTH, THICKNESS OR SIMILAR LINEAR DIMENSIONS; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS
- G01B7/00—Measuring arrangements characterised by the use of electric or magnetic techniques
- G01B7/16—Measuring arrangements characterised by the use of electric or magnetic techniques for measuring the deformation in a solid, e.g. by resistance strain gauge
-
- 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
- G01L1/12—Measuring force or stress, in general by measuring variations in the magnetic properties of materials resulting from the application of stress
- G01L1/125—Measuring force or stress, in general by measuring variations in the magnetic properties of materials resulting from the application of stress by using magnetostrictive means
-
- 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
- G01L1/16—Measuring force or stress, in general using properties of piezoelectric devices
-
- H—ELECTRICITY
- H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
- H10N—ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
- H10N30/00—Piezoelectric or electrostrictive devices
- H10N30/01—Manufacture or treatment
- H10N30/07—Forming of piezoelectric or electrostrictive parts or bodies on an electrical element or another base
- H10N30/072—Forming of piezoelectric or electrostrictive parts or bodies on an electrical element or another base by laminating or bonding of piezoelectric or electrostrictive bodies
- H10N30/073—Forming of piezoelectric or electrostrictive parts or bodies on an electrical element or another base by laminating or bonding of piezoelectric or electrostrictive bodies by fusion of metals or by adhesives
-
- H—ELECTRICITY
- H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
- H10N—ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
- H10N30/00—Piezoelectric or electrostrictive devices
- H10N30/20—Piezoelectric or electrostrictive devices with electrical input and mechanical output, e.g. functioning as actuators or vibrators
- H10N30/204—Piezoelectric or electrostrictive devices with electrical input and mechanical output, e.g. functioning as actuators or vibrators using bending displacement, e.g. unimorph, bimorph or multimorph cantilever or membrane benders
-
- H—ELECTRICITY
- H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
- H10N—ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
- H10N30/00—Piezoelectric or electrostrictive devices
- H10N30/20—Piezoelectric or electrostrictive devices with electrical input and mechanical output, e.g. functioning as actuators or vibrators
- H10N30/208—Piezoelectric or electrostrictive devices with electrical input and mechanical output, e.g. functioning as actuators or vibrators using shear or torsion displacement, e.g. d15 type devices
Definitions
- the present invention is directed to the directional attachment of an actuator/sensor to a substrate. More specifically, the present invention is directed to the directional attachment of an actuator/sensor to a substrate such that it is possible to actuate/sense strains in the substrate in a desired direction, regardless of the passive stiffness properties of the substrate, actuator element, or sensor element.
- a structure can only be actuated by a piezoelectric, magnetostrictive, thermally actuated lamina (including bimetallic) or shape memory alloy (SMA) elements isotropically, which means that a twist or torsional deflection can be produced in the structure if and only if it is fully attached and extension-twist or bending-twist coupled.
- SMA shape memory alloy
- FIG. 7 shows two fully attached actuator/sensor elements 10 attached to a substrate 30 in a bending-twist coupled arrangement.
- Figure 8 shows two fully attached
- actuator/sensor elements 10 attached to a substrate 30 in an extension twist coupled arrangement.
- these arrangements do not allow twist or torsional deflections in a substrate to be actuated or sensed regardless of the passive structural properties of the substrate.
- Coupling actuator/sensor elements to structures has been shown to be particularly useful in controlling and reducing vibration in several types of aeronautical and aerospace structures. Applications include vibration suppression in space trusses, dynamic control of camber and twist for gust alleviation and flutter suppression on fixed wing surfaces. Vibration suppression in rotorcraft could also be enhanced through the use of intelligent actuators because current methods of vibration reduction in
- helicopters including differences in individual blade tracking and magnitude and locations of dynamic stall.
- intelligent actuators can impart, direct manipulation of the rotor blade and bending is currently not feasible.
- the strain energy in a beam demonstrates the relationship between the passive structure or substrate (laminate, lam.) and the actuator/sensor (a/s) as follows:
- N number of plys
- k individual ply
- z distance through the thickness, as given in Jones, 1975.
- the strain actuation matrix is composed of actuation voltages, E x , and charge coefficients, d xx , and according to equation 29 from a paper titled "Development of Piezoelectric Technology for
- d 33 direct charge coefficient ( ⁇ strain/ (V/mm) )
- d 15 shear coupling charge ( ⁇ strain/ (V/mm) )
- the strain sensing matrix is composed of sensing voltages, V x , and voltage coefficitnt ⁇ , g xx .
- V 1 potential across crystal in longitudinal
- V 2 potential across crystal in transverse direction
- V 3 potential across crystal in thickness direction
- g 31 transverse voltage coefficient
- actuation/sensing that current (isotropic) types of fully attached actuator/sensor elements can actuate/sense are longitudinal extension, ⁇ 0 11 , lateral extension, ⁇ 0 22 , longitudinal bending, k 11 , and lateral bending, k 22 .
- ⁇ 0 11 cannot be distinguished from ⁇ 0 22 ' and k 11 cannot be distinguished from k 22 .
- the shear strain, ⁇ 0 12 , and the twist, k 12 cannot be actuated or sensed at all. Disclosure of the Invention
- one object of the present invention is to provide a novel system of directionally attaching of an actuator/sensor to a structure in which it is possible to sense a strain in the structure or actuate the structure in a desired direction, regardless of the passive stiffness properties of the structure, actuator element, or sensor element.
- Another object of the present invention is to attach an actuator/sensor to a structure such that torsional and bending deflections can be actuated/sensed.
- Yet a further object of the present invention is to attach an actuator/sensor to a structure such that the actuator/sensor behaves in an anisotropic way.
- apparatus, system and method for actuating or sensing strains in a substrate including at least one
- actuator/sensor element having transverse and longitudinal axes, wherein the actuator/sensor element is attached to the substrate in such a manner that the stiffness of the actuator/sensor element differs in the transverse and longitudinal axes of the actuator/sensor element.
- FIGURE 1a and 1b represents first and second
- FIGURE 2 (a-h) represents alternative techniques of a directionally attached actuator/sensor
- FIGURE 3 represents a third embodiment of a
- FIGURE 4 represents a side view of the embodiment of FIGURE 3;
- FIGURE 5 represents an end view of the embodiment of FIGURE 3 .
- FIGURE 6 represents an aeronautical element utilizing particular actuator/sensors of piezoelectric crystals which are directionally attached;
- FIGURE 7 represents a bending-twist coupled
- FIGURE 8 represents an extension-twist coupled
- FIGURE 9 represents a feedback control system for use with a directionally attached actuator/sensor system.
- FIGURE 1(a) thereof, in which a first embodiment of a directionally attached piezoelectric actuator/sensor of the present invention is shown.
- the present invention can operate utilizing
- piezoelectric, magnetostrictive, shape memory alloy (SMA) and thermally actuated lamina (including bimetallic) actuator/sensor elements and in a preferred embodiment utilizes piezoelectric actuator/sensor elements.
- the present invention can operate in a preferred embodiment utilizing conventional stamped and extruded piezoelectric elements.
- Conventional stamped piezoelectric elements have been found to be about 1.5 times more effective than extruded piezoelectric elements.
- the present invention is operable on any substrates which actuator/sensor elements are
- conventional circuitry can be used to generate and apply to the actuator element actuation signals, or to sense signals produced by the element in the detection of strains occurring in a
- the present invention utilizes a system of directional attachment of an actuator or sensor element onto a
- the present invention utilizes a partial attachment system as shown in FIGURE 1(a), in which a portion of the
- actuator/sensor is made inactive in one strain (i.e., the transverse strain) and is made active in the other strain (i.e., the longitudinal strain).
- an actuator/sensor 10 is attached to a substrate 30 only in the area defined as the area of attachment 20. This area of attachment can take on an area in the range of
- FIGURE 1(b) represents an inverse ellipse partial attachment pattern which the area of attachment between the actuator/sensor and substrate can take on to achieve the same results as that of FIGURE 1(a).
- the actuator/sensor elements can be attached to the substrate using conventional surface bonding techniques utilizing a bonding agent such as M-Bond 200TM manufactured by The Loctite Co. (through M-Line Products) or a
- actuator/sensor elements is by embedding the
- Figure 2(a) shows the inverse elipse pattern described in Figure 1(b) above and Figure 2(b) shows the central third attachment pattern described in Figure 1(a) above.
- the bonding agent may also be only applied to the piezoelectric element at its edge portions in its traverse axes.
- the actuator/sensor element need only be rigidly attached at its transverse axes edges.
- the actuator/sensor element can be embedded in the substrate utilizing any of the above cited patterns so long as the edges in the transverse axes are rigidly attached and the edges in the longitudinal axes are
- actuator/sensor element is either placed on the surface of the substrate on embedded into the substrate. That is, with reference to Figures 2(e-h), the actuator/sensor elements will be embedded into a slot in the substrate.
- the size of the slot in the substrate can be manipulated to provide the flexible and rigid attachment areas. That is, if the size of the slot in the substrate is chosen such that the actuator/sensor element fits snugly in the slot in the longitudinal direction and loosely in the slot in the transverse directions, then the rigid (snug) and flexible (loose) attachments as shown in Figures 2(e-h) will be effectuated.
- the slot in which the actuator/sensor element is embedded then must be slightly larger than the
- actuator/sensor element in the transverse direction, allowing enough extra space for the actuator/sensor element to expand and just large enough in the longitudinal
- the manner in which the actuator/sensor element is placed on the surface of the substrate can also effectuate a rigid attachment at its transverse axis edges. This can be accomplished, for example, by placing the actuator/sensor element between two rigid members which extend above the surface of the
- FIGURES 1 and 2 operate such that when the actuator/sensor element becomes active, stress is rapidly distributed to the free edges in the longitudinal strain. In this way, the embodiments of FIGURES 1 and 2 operate such that the unattached sides of the actuator/sensor element contribute to the longitudinal stiffness of the element and therefore make the
- actuator/sensor element impart more longitudinal than transverse stiffness to the substrate.
- the end effect is that the stiffness of the actuator/sensor as seen from the substrate is greater in the longitudinal direction than it is in the transverse direction.
- FIGURES 3-5 show a second system of attaching an actuator/sensor to a substrate in such a way that the same results as described with reference to FIGURES 1 and 2 are achieved.
- the system of FIGURES 3-5 achieves these results by increasing the aspect ratio and bond line thickness of the actuator/sensor element to the point where the finite amount of shear lag present in the bond line significantly reduces the transverse stiffness of the element.
- the aspect ratio is defined as L a/s /W a/s and the bond line thickness is shown as B T in Figures 3-5.
- the aspect ratio should take on values greater than 10:1 and the bond line thickness should be approximately the same as the
- FIGURES 3-5 detail exaggerated deflections of the bonding material to illustrate the finite shear lag in longitudinal and
- actuator/sensor Le reflects the effective length of the actuator that actually produces strain in the substrate or the length of the sensor that actually has strain produced in it by the substrate.
- the ratio of the effective length of the actuator/sensor Le divided by the actual length La/s should be approximately equal to one.
- Le/La should be a factor of 2 or more greater than the width effectiveness ratio, We/Wa.
- transverse shear lag can produce the beneficial effect of further reducing the effective width of the actuator/sensor while maintaining a high effective length.
- FIGURES 1 and 2 utilize a system which combines the partial attachment technique of FIGURES 1 and 2 with the transverse shear lag techniques of FIGURES 3-5.
- Equation 1 Since directional attachment effectively reduces the stiffnesses of the actuator/sensor, E Ta/s ⁇ E La/s . From equations 1 the reduced stiffnesses, E* 1111a/s ⁇ E* 2222a/s and from equations 2, the rotated reduced stiffnesses are not equal to the non-rotated values with E 1112a/s ⁇ 0, E 2212a/s ⁇ 0. The resulting actuation/sensing stiffness matrix is fully populated. With the implementation of directional attachment, equation 3 takes the form of equation 8.
- V Equation 8 shows that through directional attachment, any mode of strain can be forced/detected if the
- actuator/sensor is sensitive to just one or two extensional strains: ⁇ 0 11 and/or ⁇ 0 22 .
- Most types of sensor/actuator materials are isotropic and sensitive in just this way. And as demonstrated by equations 4 through 7,
- actuator/sensor elements are particularly well suited for directional attachment.
- Figure 6 shows one implementation of directionally attaching actuator/sensor elements onto an aeronautical member such as an airfoil or rotor blade.
- those actuator/sensor elements are piezoelectric elements, but may also be magnetostrictive, shape memory alloys or thermally actuated lamina (including bi-metallix) elements. As shown in
- FIG. 6 a plurality of piezoelectric elements 10, as represented by the dark lines, are attached to an
- the piezoelectric elements 10 are attached in one of the above-described techniques, that is,
- the piezoelectric elements 10 will behave in an anisotropic way and thus are able to impart a torsional deflection or sensing to the aeronautical element. This torsional deflection or sensing can then be implemented for such reasons as vibration reducing, in-flight tracking blade and dynamic stall reduction. Attaching the piezoelectric elements 10 at a 45° to the aeronautical member 50 allows the piezoelectric elements 10 to maximize the torsional deflection imparted or sensed to or from the aeronautical member 50. However, the angle of the piezoelectric
- the elements can take on any value dependent on the amount of torsional deflection to be actuated or sensed. It is noted that the spacing of the piezoelectrical elements in this configuration is important. If the spacing is too large, then the effective density is reduced. If the spacing is too small, then capillary action may draw the bonding agent between the piezoelectric elements. If the bonding agent accumulates between the crystals, then the directionality is destroyed as the behavior of the piezoelectric elements becomes quasi-isotropic; and accordingly, twist and
- the directional attachment techniques of the present invention may have many applications such as actuation and sensing of rotor blade and aircraft wing twist and bending distribution, actuation and sensing of space-based structures including space-trusses,
- torque actuation and sensing including simultaneously actuating and sensing high frequency variations in torque and bending loads, and use in Multi-mode accelerometers.
- directionally attached actuator/sensor elements can be accomplished in several ways, each being slightly different than the others as the different types of actuator/sensor materials behave differently.
- the voltage signal can be steady-state, time-variant, or impulse.
- Each of the types of actuations will produce specific deflections as prescribed by the manufacturers. If the directionally attached piezoelectric crystals are used for sensing, an impulsive, steady-state or time-variant structural strain will produce voltages across the crystal faces according to the manufacturers data. These sensed voltages or actuated strains can be used alone (for structural actuation only or structural sensing only) or simultaneously in a feedback loop
- the aeronautical member or rotor blade shown in Figure 6 can utilize the feedback loop arrangement shown in Figure 9.
- Fexternal and Fpiezo is a signal represented as Fnet in Figure 9 which is then input into the feedback loop.
- This signal Fnet represents a signal to be cancelled by the feedback loop. That is, this signal Fnet is to be
- aeronautical member will vary from one aeronautical member to the other and is represented in Figure 9 as box 110, Blade Structure.
- the signal Fnet then, which will be a function of the specific blade structure of the
- aeronautical member as represented by box 110 can be represented by a function of three signals , displacement X, velocity X', and acceleration X", as shown in Figure 9. In the present case, it is the displacement X of the
- the piezoelectric sensor 120 will sense the displacement in the aeronautical member and output it as a voltage signal represented as V x in Figure 9.
- This signal V x then will be fed into a signal conditioner 130.
- the specifics of the signal conditioner 130 will vary from application to application and any conventional signal conditioner which acts in such piezoelectric circuits may be employed, such as a PCB Brand Model 482A04.
- the signal output from the signal conditioner 130 will then be fed into an amplifier 140 which multiplies the signal by k.
- the output from this amplifier 140 will then be applied to the piezoelectric actuators 150.
- a certain force will then be imparted onto the piezoelectric actuators as represented by Fpiezo in Figure 9. In this way, Fpiezo will approach Fexternal and consequently Fnet will be minimized.
- the magnetic field is generated (most frequently) through the use of electrical current passing through wires near-by or surrounding the magnetostrictive element.
- the magnetic field causes the element to expand which induces structural strains.
- structural strains induce the magnetostrictive element to create a magnetic field which is sensed by electrical wires adjacent to the element.
- the control loop arrangement is similar to that shown in Figure 9 can be employed utilizing magnetostrictive elements, but with an intermediate magnetic field. Again, the
- magnetostrictive elements can be used for sensing alone, actuation alone, or actuation and sensing at the same time.
- strains can be induced by the use of a thermal, electrical, or electro-thermal triggers. No sensing is currently feasible with the use of shape-memory alloys.
- thermal changes or gradients must be applied to the laminate to produce strains.
- Two or more materials that have different coefficients of thermal expansions can be directionally attached so as to impart orthotropic actuation loads.
Landscapes
- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Aviation & Aerospace Engineering (AREA)
- Manufacturing & Machinery (AREA)
- Micromachines (AREA)
- General Electrical Machinery Utilizing Piezoelectricity, Electrostriction Or Magnetostriction (AREA)
Abstract
L'invention se rapporte à un appareil, à un système et à un procédé qui servent à activer ou à détecter des contraintes dans un substrat (30) et qui utilisent au moins un élément actuateur/détecteur (10) ayant un axe transversal et un axe longitudinal. L'élément actuateur/détecteur (10) est fixé au substrat (30) de façon à ce que la rigidité de l'élément actuateur/détecteur (10) dans l'axe transversal soit différente de sa rigidité dans l'axe longitudinal. Ainsi, on peut détecter ou activer des contraintes, s'exerçant dans le substrat (30), dans une direction désirée, quelles que soient les propriétés de rigidité passive du substrat, de l'élément actuateur ou de l'élément détecteur. Un élément actuateur/détecteur isotrope (10) fixé à un substrat (30) de cette manière peut alors fonctionner de manière anisotrope. Dans un mode de réalisation préféré, l'élément actuateur/détecteur (10) est collé au substrat (30) dans une zone de fixation (20) occupant seulement le tiers central de l'élément actuateur/détecteur (10) dans son axe longitudinal. L'élément actuateur/détecteur (10) peut être constitué par un élément piézo-électrique, magnétostrictif fait de lames (y compris bimétalliques) thermiquement activées ou d'un alliage à mémoire de forme.An apparatus, system and method for activating or detecting stresses in a substrate (30) and using at least one actuator / detector element (10) having a transverse axis and a longitudinal axis. The actuator / detector element (10) is fixed to the substrate (30) so that the rigidity of the actuator / detector element (10) in the transverse axis is different from its rigidity in the longitudinal axis. Thus, one can detect or activate stresses, acting in the substrate (30), in a desired direction, whatever the passive stiffness properties of the substrate, the actuator element or the detector element. An isotropic actuator / detector element (10) fixed to a substrate (30) in this way can then operate anisotropically. In a preferred embodiment, the actuator / detector element (10) is bonded to the substrate (30) in a fixing zone (20) occupying only the central third of the actuator / detector element (10) in its longitudinal axis. . The actuator / detector element (10) may consist of a piezoelectric, magnetostrictive element made of thermally activated blades (including bimetallic) or of a shape memory alloy.
Description
Claims
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US48559990A | 1990-02-27 | 1990-02-27 | |
US485599 | 1990-02-27 |
Publications (2)
Publication Number | Publication Date |
---|---|
EP0527135A1 true EP0527135A1 (en) | 1993-02-17 |
EP0527135A4 EP0527135A4 (en) | 1993-11-03 |
Family
ID=23928760
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
EP19910904828 Withdrawn EP0527135A4 (en) | 1990-02-27 | 1991-02-22 | Method and apparatus for structural actuation and sensing in a desired direction |
Country Status (3)
Country | Link |
---|---|
EP (1) | EP0527135A4 (en) |
JP (1) | JPH05508117A (en) |
WO (1) | WO1991012953A1 (en) |
Families Citing this family (8)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US5440193A (en) * | 1990-02-27 | 1995-08-08 | University Of Maryland | Method and apparatus for structural, actuation and sensing in a desired direction |
US5424596A (en) * | 1992-10-05 | 1995-06-13 | Trw Inc. | Activated structure |
US6791098B2 (en) | 1994-01-27 | 2004-09-14 | Cymer, Inc. | Multi-input, multi-output motion control for lithography system |
US6404107B1 (en) | 1994-01-27 | 2002-06-11 | Active Control Experts, Inc. | Packaged strain actuator |
US6781285B1 (en) | 1994-01-27 | 2004-08-24 | Cymer, Inc. | Packaged strain actuator |
US6959484B1 (en) | 1994-01-27 | 2005-11-01 | Cymer, Inc. | System for vibration control |
US6420819B1 (en) * | 1994-01-27 | 2002-07-16 | Active Control Experts, Inc. | Packaged strain actuator |
US5869189A (en) * | 1994-04-19 | 1999-02-09 | Massachusetts Institute Of Technology | Composites for structural control |
Family Cites Families (7)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US2558563A (en) * | 1948-10-29 | 1951-06-26 | Gen Electric | Piezoelectric strain gauge |
US2920480A (en) * | 1956-01-18 | 1960-01-12 | Haas Tibor | Methods for indicating the expiration of the assigned or safe life of structural members |
US3136154A (en) * | 1958-11-20 | 1964-06-09 | Douglas Aircraft Co Inc | Fatigue monitor |
GB1149636A (en) * | 1966-04-20 | 1969-04-23 | Vitaly Alexandrovich Vinokurov | Method and apparatus for measuring residual stresses in structural members |
US3786679A (en) * | 1972-04-12 | 1974-01-22 | Battelle Memorial Institute | Fatigue indication |
US4725020A (en) * | 1980-12-09 | 1988-02-16 | The Boeing Company | Control system incorporating structural feedback |
IT206727Z2 (en) * | 1985-09-17 | 1987-10-01 | Marelli Autronica | THICK FILM EXTENSIMETRIC SENSOR FOR DETECTION OF STRESSES AND DEFORMATIONS IN ORGANS OR MECHANICAL STRUCTURES |
-
1991
- 1991-02-22 EP EP19910904828 patent/EP0527135A4/en not_active Withdrawn
- 1991-02-22 WO PCT/US1991/001060 patent/WO1991012953A1/en not_active Application Discontinuation
- 1991-02-22 JP JP91505574A patent/JPH05508117A/en active Pending
Non-Patent Citations (2)
Title |
---|
No further relevant documents disclosed * |
See also references of WO9112953A1 * |
Also Published As
Publication number | Publication date |
---|---|
EP0527135A4 (en) | 1993-11-03 |
JPH05508117A (en) | 1993-11-18 |
WO1991012953A1 (en) | 1991-09-05 |
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