Summary of the invention
In order to solve the problems, such as body surface multi-physiological-parameter multimetering, and solves the energy supply that sensor continues working and askTopic, the invention proposes the passive sensing networks for being suitable for material surface physiological compensation effects.The present invention is based on a kind of multi-directionThe Multi-angle ultrasound energy converter of transmitting arranges multiple surface acoustic wave sensing units, around the energy converter with material surface itselfFor acoustical signal transmission channel, Multi-angle ultrasound energy converter provides instantaneous operating power source, and reception sound for surface acoustic wave sensing unitSurface wave sensing unit returns to the monitoring signals of coming, and then reads the measured material surface supplemental characteristic of analysis.
An object of the present invention is to provide a kind of passive sensing networks suitable for material surface parameter monitoring.
Passive sensing network suitable for material surface parameter monitoring of the invention includes: control circuit, Multi-angle ultrasoundEnergy converter and multiple surface acoustic wave sensing units；Wherein, control circuit is electrically connected to Multi-angle ultrasound energy converter；Multi-angle is superSonic transducer half is embedded in detected materials surface；Multiple abutting measured material surfaces are arranged on the periphery of Multi-angle ultrasound energy converterSurface acoustic wave sensing unit；Control circuit issues control signal to multi-angle ultrasonic transducer, and the form for controlling signal is telecommunicationsNumber；Using Multi-angle ultrasound energy converter as communication node, using detected materials surface as communication channel, using acoustical signal as energy andThe carrier of signal carries out energy with each surface acoustic wave sensing unit for being arranged in Multi-angle ultrasound energy converter periphery or information passesIt is defeated；Multi-angle ultrasound energy converter converts the electrical signal to acoustical signal；Acoustical signal propagates surface acoustic wave sensing along detected materials surfaceUnit receives acoustical signal, perceives the measured material surface parameter around position, and will carry measured material surface parameter letterThe acoustical signal of breath is back to Multi-angle ultrasound energy converter by measured material surface；Multi-angle ultrasound energy converter changes acoustical signalAt control circuit is transmitted to after electric signal, the information on measured material surface is analyzed and extracted to control circuit, and then realizes to testedIt is monitored while material surface multiple spot multi-parameter.
Control circuit includes: that energy issues module and signal analysis module；Wherein, energy issues module and issues with energyControl signal, such as transient pulse etc., and be transmitted to Multi-angle ultrasound energy converter；Signal analysis module handles Multi-angle ultrasoundThe information on measured material surface is extracted and analyzed to the acoustical signal that energy converter receives.
Multi-angle ultrasound energy converter includes center mass layer, main piezo crystals lamella harmony matching layer；Wherein, center mass layerShape be polygon terrace with edge, the number of edges of polygon terrace with edge is 3~10, and center mass layer uses high density material；PolygonA piece of piezoelectric chip is respectively set in each side of the center mass layer of shape prismatic table shape, thus in the side of polygon terrace with edge oneWeek forms main piezo crystals lamella, keeps independent mutually in the piezoelectric chip of different directions；It is set in the outer surface of main piezo crystals lamellaSet one layer of acoustic matching layer；To form the Multi-angle ultrasound energy converter of polygon inverted trapezoidal shape, Multi-angle ultrasound energy converterUpper surface is less than lower surface, and the top half of Multi-angle ultrasound energy converter is embedded in measured material surface；Control circuit is electrically connected toMain piezo crystals lamella；Control circuit sends an electrical signal to main piezo crystals lamella, causes each mutual of center mass layer outer surfaceIndependent piezoelectric chip vibration, converts the electrical signal to acoustical signal, and center mass layer is guaranteed each mutually only by big inertiaFor vertical piezoelectric chip in vibration, Multi-angle ultrasound energy converter does not have big positional shift, and acoustic matching layer reduces acoustical signalEnergy attenuation when propagating from from Multi-angle ultrasound energy converter to measured material surface, improves propagation efficiency；When surface acoustic wave sensesWhen unit returns to the acoustical signal for carrying measured material surface parameter information by measured material surface, is reduced and passed by acoustic matching layerEnergy attenuation is broadcast, main piezo crystals lamella experiences vibration, converts acoustic signals into electric signal, and be transmitted to control circuit.
Surface acoustic wave sensing unit includes: surface acoustic wave transducing portion and surface acoustic wave transducing part, is passed through therebetweenConducting wire connection；Surface acoustic wave transducing portion receives the acoustical signal propagated along measured material surface, and acoustical signal is converted to telecommunicationsIt number is transmitted to surface acoustic wave transducing part, surface acoustic wave transducing part perceives the parameter on surrounding measured material surface, and will carryThe electric signal transmission of measured material surface parameter information to surface acoustic wave transducing portion, surface acoustic wave transducing portion turns electric signalIt is changed to acoustical signal, and Multi-angle ultrasound energy converter is transmitted to by measured material surface.The upper surface of surface acoustic wave transducing portionLess than lower surface, the top of surface acoustic wave transducing portion is partly embedded in measured material surface.
Surface acoustic wave transducing portion includes acoustic impedance matching layer, unit piezo crystals lamella and big quality structure layer；Wherein, existAcoustic impedance matching layer is arranged in the front surface of unit piezo crystals lamella, and big quality structure is arranged in the rear surface of unit piezo crystals lamellaLayer；Acoustic impedance matching layer faces Multi-angle ultrasound energy converter, so that low damply passing along the acoustical signal that measured material surface is propagatedSurface acoustic wave transducing portion is transported to, the receiving efficiency of surface acoustic wave transducing portion is improved；Unit piezo crystals lamella experiences vibrationAnd acoustical signal is converted into electric signal, it is transmitted to surface acoustic wave transducing part；Electric signal from surface acoustic wave transducing part drawsPlay the vibration of unit piezo crystals lamella, convert electrical signals to acoustical signal, big quality structure layer guarantee acoustical signal towards it is given forwardIt propagates in direction；Acoustic impedance matching layer makes acoustical signal is low damply to propagate to measured material surface, improves propagation efficiency.
Unit piezo crystals lamella is tabular, and the front surface of the rear surface of impedance matching layer and big quality structure layer is flatFace is separately positioned on the front surface and rear surface of unit piezo crystals lamella；The upper surface of impedance matching layer and big quality structure layerRespectively less than lower surface.The upper and lower surfaces of surface acoustic wave transducing portion are vertical with front surface and rear surface.
Surface acoustic wave transducing part includes piezoelectric sheet layer, sensitive layer and interdigital electrode；Wherein, piezoelectric sheet layer is as soundThe propagation medium of signal uses piezoelectric material；Sensitive layer and interdigital electrode are separately positioned on piezoelectric sheet layer；Interdigital electrode clothIt sets in the centre of piezoelectric sheet layer, or is arranged in the both ends for being located at sensitive layer on piezoelectric sheet layer；Interdigital electrode uses metalMaterial；The electric signal that unit piezo crystals lamella transmits is converted to acoustical signal and passed on the surface of piezoelectric sheet layer by interdigital electrodeIt broadcasts, sensitive layer perceives the parameter on surrounding measured material surface, when parameter (temperature, humidity) changes, sensitive layer and piezoelectricityLamella interaction, and influence acoustical signal surface wave propagation characteristic；Interdigital electrode will carry measured material surface parameter letterThe acoustical signal of breath is converted to electric signal, and is transmitted to unit piezo crystals lamella.
Measured material can be soft material, be also possible to hard material；If measured material is soft material, Multi-angle ultrasound is changedMeasured material surface is close in the upper surface of energy device and surface acoustic wave transducing portion, and applies in pressure indentation soft material, so that softMaterial deformation is recessed, so that the upper surface of Multi-angle ultrasound energy converter and surface acoustic wave transducing portion half is embedded in measured material tableIn face；It is preset with Multi-angle ultrasound energy converter harmony surface on measured material surface in advance if measured material is hard materialThe recess that wave transducing portion matches, so that the upper surface of the two half is embedded in measured material surface.
It is another object of the present invention to provide a kind of passive sensing networks suitable for material surface parameter monitoringMethod for sensing.
The method for sensing of passive sensing network suitable for material surface parameter monitoring of the invention, comprising the following steps:
1) control circuit issues control signal to multi-angle ultrasonic transducer, and the form for controlling signal is electric signal；
2) Multi-angle ultrasound energy converter converts the electrical signal to acoustical signal；
3) acoustical signal is propagated along detected materials surface；
4) surface acoustic wave sensing unit receives acoustical signal, and converts acoustic signals into electric signal；
5) the measured material surface parameter around surface acoustic wave sensing unit perception position；
6) acoustical signal for carrying measured material surface parameter information is passed through measured material surface by surface acoustic wave sensing unitIt is back to Multi-angle ultrasound energy converter；
7) Multi-angle ultrasound energy converter is transmitted to control circuit after acoustical signal is transformed into electric signal；
8) information on measured material surface is analyzed and extracted to control circuit, and then realizes and join to measured material surface multiple spot moreIt is monitored while number.
Wherein, in step 2), Multi-angle ultrasound energy converter converts the electrical signal to acoustical signal, specifically includes following stepIt is rapid:
A) electric signal sent from control circuit causes each mutual of center mass layer outer surface to main piezo crystals lamellaIndependent piezoelectric chip vibration, converts the electrical signal to acoustical signal；
B) center mass layer guarantees each mutually independent piezoelectric chip in vibration, multi-angle is super by big inertiaSonic transducer does not have big positional shift；
C) energy that acoustic matching layer reduces when acoustical signal is propagated from Multi-angle ultrasound energy converter to measured material surface declinesSubtract, improves propagation efficiency.
In step 3), the top half of Multi-angle ultrasound energy converter and surface acoustic wave transducing portion is embedded in measured material surfaceIt is interior, so that main piezo crystals lamella carries out acoustical signal communication propagation and unit piezoelectricity by acoustic matching layer and measured material surfaceWafer layer carries out acoustical signal communication by acoustic impedance matching layer and measured material surface and propagates.
In step 4), surface acoustic wave sensing unit receives acoustical signal, and converts acoustic signals into electric signal, specifically includesFollowing steps:
A) acoustic impedance matching layer faces Multi-angle ultrasound energy converter, so that low declining along the acoustical signal that measured material surface is propagatedIt is transmitted to surface acoustic wave transducing portion with subtracting；
B) unit piezo crystals lamella, which is experienced, vibrates and acoustical signal is converted to electric signal, is transmitted to surface acoustic wave detecting meansPoint.
In step 5), surface acoustic wave sensing unit perceives measured material surface parameter, specifically includes the following steps:
A) electric signal that unit piezo crystals lamella transmits is converted to acoustical signal and in the table of piezoelectric sheet layer by interdigital electrodeIt propagates in face；
B) parameter on sensitive layer perception surrounding measured material surface, when parameter changes, sensitive layer and piezoelectric sheetLayer interaction, and influence acoustical signal surface wave propagation characteristic；
C) acoustical signal for carrying measured material surface parameter information is converted to electric signal by interdigital electrode, and is transmitted to listFirst piezo crystals lamella.
In step 6), acoustical signal is back to Multi-angle ultrasound by measured material surface and changed by surface acoustic wave sensing unitEnergy device, specifically includes the following steps:
A) electric signal from surface acoustic wave transducing part causes unit piezo crystals lamella to vibrate, and converts electrical signals to soundSignal；
B) big quality structure layer guarantees that acoustical signal is propagated towards assigned direction；
C) acoustic impedance matching layer makes acoustical signal is low damply to propagate to measured material surface, improves propagation efficiency.
In step 7), acoustical signal is transformed into after electric signal by Multi-angle ultrasound energy converter is transmitted to control circuit, specificallyThe following steps are included:
A) acoustical signal of the carrying measured material surface parameter information returned by measured material surface, passes through acoustic matching layerSo that propagating to main piezoelectric chip with reducing energy attenuation；
B) main piezo crystals lamella experiences vibration, converts acoustic signals into electric signal, and be transmitted to control circuit.
In step 8), control circuit processing analysis extracts the information on measured material surface, specifically includes: control electricityThe acoustical signal that receives of signal analysis module processing Multi-angle ultrasound energy converter on road, the acoustical signal medium wave peak returned by monitoring itBetween time difference or the spectral characteristic of acoustical signal judge the feature of the inner material on measured material surface.
Passive sensing network of the invention can be used for the physiological parameter of engineering structure surface parameter measurement or human body surfaceMonitoring.
Advantages of the present invention:
Using the acoustical signal small feature of propagation attenuation on the surface of the material, use material surface as ultrasound-transmissive channel, intoAnd solve decaying, wiring and it is anti-interference the problems such as；Using the instantaneous working characteristics of surface acoustic wave sensing unit, instantaneous sound is usedSignal provides its operating power source, so that sensor itself no longer needs battery supplied；Using Multi-angle ultrasound energy converter, in conjunction with moreA surface acoustic wave sensing unit realizes the multiposition of material surface multiple parameters while measuring, and forms measurement network.
Specific embodiment
With reference to the accompanying drawing, by specific embodiment, the present invention is further explained.
As shown in Figure 1, the passive sensing network suitable for material surface parameter monitoring of the present embodiment includes: control circuit3, Multi-angle ultrasound energy converter 1 and multiple surface acoustic wave sensing units 2；Wherein, control circuit is electrically connected to Multi-angle ultrasoundEnergy converter 1；Multi-angle ultrasound energy converter 1 half is embedded in detected materials surface 4；On the periphery of Multi-angle ultrasound energy converter, arrangement is multipleIt is close to the surface acoustic wave sensing unit 2 on measured material surface.Signal connection and acoustic-electric conversion regime are as shown in Figure 2.
As shown in figure 3, Multi-angle ultrasound energy converter includes center mass layer 13, main piezo crystals lamella 12 and acoustic matching layer11；Wherein, the shape of center mass layer 13 is 8 side shape terrace with edges, and center mass layer 13 uses high density material；In polygon terrace with edgeA piece of piezoelectric chip is respectively set in each side of the center mass layer of shape, to be formed within one week in the side of polygon terrace with edgeMain piezo crystals lamella 12 keeps independent mutually in the piezoelectric chip of different directions；It is arranged one in the outer surface of main piezo crystals lamellaLayer acoustic matching layer 13；To form the Multi-angle ultrasound energy converter of polygon inverted trapezoidal shape, Multi-angle ultrasound energy converter it is upperSurface is less than lower surface.In the present embodiment, the upper surface of the centrally disposed quality layers 13 of control circuit 3.
As shown in figure 4, Multi-angle ultrasound energy converter 1 using measured material surface as communication channel, is sensed with surface acoustic waveThe transmission of 2 acoustical signal of unit.
As shown in figure 5, surface acoustic wave sensing unit includes: surface acoustic wave transducing portion and surface acoustic wave transducing part；SoundSurface wave transducing portion includes acoustic impedance matching layer 21, unit piezo crystals lamella 22 and big quality structure layer 23；Wherein, in unitAcoustic impedance matching layer 21 is arranged in the front surface of piezo crystals lamella 22, and big quality structure is arranged in the rear surface of unit piezo crystals lamellaLayer 23.Surface acoustic wave transducing part includes piezoelectric sheet layer 24, sensitive layer 25 and interdigital electrode 26；Wherein, piezoelectric sheet layer 24Propagation medium as acoustical signal uses piezoelectric material；Sensitive layer 25 and interdigital electrode 26 are separately positioned on piezoelectric sheet layer；Interdigital electrode 26 is arranged in the both ends for being located at sensitive layer 25 on piezoelectric sheet layer.
Passive sensing network can be affixed on body surface, such as abdomen, back, upper limb or lower limb position, sensing networkCentral node is Multi-angle ultrasound transducer architecture 1, which is responsible for providing pulse energy and processing returns to the acoustical signals come.?Around Multi-angle ultrasound transducer architecture 1, it is furnished with multiple surface acoustic wave sensing units 2,1 harmony of Multi-angle ultrasound transducer architectureUsing human body as communication channel between surface wave sensing unit 2, energy is carried out as the carrier of energy and signal using sound wave or information passesIt is defeated.Surface acoustic wave sensing unit 2 can realize the measurement to a variety of physiological parameters, by taking abdomen as an example, the parameter that can be monitored include butIt is not limited to body temperature, heartbeat signal, breath signal, bladder signal etc..
When human body physiological parameter generation quantitatively changes, it will lead to the object properties of the sensitive layer of surface acoustic wave transducing partVariation, or directly result in surface acoustic wave transducing part physical characteristic itself and change, thus lead to surface acoustic wave detecting meansCorresponding quantitative variation can also occur for the velocity of wave or resonant frequency divided, therefore can pass through the acoustical signal medium wave peak of monitoring returnBetween time difference or the spectral characteristic of acoustical signal judge the characteristic of physiological signal.In addition, when interdigital electrode is arranged in pressureVelocity of wave variation when being located at the both ends of sensitive layer on electric lamella, in detectable signal；When interdigital electrode is arranged in piezoelectric sheetThe variation of resonant frequency when centre of layer, in detectable signal.
Here by taking the detection to human body temperature as an example, illustrate that surface acoustic wave sensing unit is to body surface signal used in the present inventionTesting principle:
When body surface temperature changes, the acoustic velocity that will lead to surface acoustic wave transducing part constituent material occursChange, the geometry spacing of interdigital electrode can also occur to change accordingly on surface acoustic wave transducing part.These variations will lead to soundQuantitative variation occurs for the resonant frequency of surface wave transducing part, also results in surface acoustic wave transducing part and is returning to energy converterSignal in, the time difference (that is, velocity of wave) between wave crest and wave crest changes.And as shown in fig. 6, the variation of shell temperature,It is in quantitative relationship between the frequency variation or the variation of velocity of wave of surface acoustic wave sensing unit, therefore can be passed from surface acoustic waveIt is poor by spectrum analysis or measurement peak peak time in the signal that sense part returns, carry out inverse body surface temperature.
In addition to for human body surface, which can also be used in engineering structure surface, such as: the measurement network can be setIn on aircraft, for detect flight each section whether by bird collisions or damage；The network can be set to long-span bridgeOn the drag-line of beam, for detecting the pulling force and Vibration Condition of drag-line；It can will change network on petroleum pipeline, for detecting oil leakAnd oil mass transmits situation.
It is finally noted that the purpose for publicizing and implementing example is to help to further understand the present invention, but this fieldTechnical staff be understood that without departing from the spirit and scope of the invention and the appended claims, it is various replacement and repairIt is all possible for changing.Therefore, the present invention should not be limited to embodiment disclosure of that, and the scope of protection of present invention is to weighSubject to the range that sharp claim defines.