CN106712246A - Self-powered sensing system based on surface acoustic wave sensor and control method thereof - Google Patents

Self-powered sensing system based on surface acoustic wave sensor and control method thereof Download PDF

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Publication number
CN106712246A
CN106712246A CN201611089960.5A CN201611089960A CN106712246A CN 106712246 A CN106712246 A CN 106712246A CN 201611089960 A CN201611089960 A CN 201611089960A CN 106712246 A CN106712246 A CN 106712246A
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China
Prior art keywords
energy
sensor
signal
circuit
acoustic wave
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牟笑静
周鸿�
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Chongqing University
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Chongqing University
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    • HELECTRICITY
    • H02GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02JCIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J7/00Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries
    • H02J7/34Parallel operation in networks using both storage and other dc sources, e.g. providing buffering
    • H02J7/345Parallel operation in networks using both storage and other dc sources, e.g. providing buffering using capacitors as storage or buffering devices
    • GPHYSICS
    • G08SIGNALLING
    • G08CTRANSMISSION SYSTEMS FOR MEASURED VALUES, CONTROL OR SIMILAR SIGNALS
    • G08C17/00Arrangements for transmitting signals characterised by the use of a wireless electrical link
    • G08C17/02Arrangements for transmitting signals characterised by the use of a wireless electrical link using a radio link
    • HELECTRICITY
    • H02GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02KDYNAMO-ELECTRIC MACHINES
    • H02K35/00Generators with reciprocating, oscillating or vibrating coil system, magnet, armature or other part of the magnetic circuit
    • H02K35/04Generators with reciprocating, oscillating or vibrating coil system, magnet, armature or other part of the magnetic circuit with moving coil systems and stationary magnets
    • HELECTRICITY
    • H02GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02NELECTRIC MACHINES NOT OTHERWISE PROVIDED FOR
    • H02N2/00Electric machines in general using piezoelectric effect, electrostriction or magnetostriction
    • H02N2/18Electric machines in general using piezoelectric effect, electrostriction or magnetostriction producing electrical output from mechanical input, e.g. generators
    • H02N2/186Vibration harvesters
    • HELECTRICITY
    • H04ELECTRIC COMMUNICATION TECHNIQUE
    • H04WWIRELESS COMMUNICATION NETWORKS
    • H04W84/00Network topologies
    • H04W84/18Self-organising networks, e.g. ad-hoc networks or sensor networks

Abstract

The invention discloses a self-powered sensing system based on a surface acoustic wave sensor and a control method thereof. The system comprises an energy collection system which is connected with a signal processing and radio frequency energy control circuit; the signal processing and radio frequency energy control circuit which is connected with a cloud side database; and the cloud side database which is used for performing interaction of cloud side data with an intelligent terminal. Control of the control method is performed through a microcontroller. The system includes an energy collector which can collect vibration energy and radio frequency energy to be used by the sensor so that the problem of performing state monitoring of a target in the environment without power or the environment having power supply difficulty and wired energy supply difficulty can be solved; when external (vibration) energy is insufficient, radio frequency energy can be emitted through a radio frequency energy emitter to be collected by the radio frequency energy collector and transmitted to the sensor for power supply; and the sensor can be actively awakened to work under the condition of insufficient external energy so as to eliminate the risk of system breakdown.

Description

A kind of self energizing sensor-based system and control method based on surface acoustic wave sensor
Technical field
The invention belongs to sensor technical field, more particularly to a kind of self energizing sensing system based on surface acoustic wave sensor System and control method.
Background technology
Surface wave sensor is that the frequency based on surface acoustic wave resonance changes with the change of measurand, so as to survey Measure a kind of novel sensor of physical quantity.The parameters such as measurement pressure, acceleration and temperature can be made with SAW device Sensor.Due to being manufactured using semiconductor integrated technique, therefore micro-structural can be made, it is lightweight, and because its output frequency Signal, so strong antijamming capability, is easy to implement Numerical Control.
Wireless sensor network (Wireless Sensor Networks, WSN) is a kind of distributed sensor, by big The wireless network that the static or mobile sensor of amount is constituted in the way of self-organizing and multi-hop.WSN nodes usually require that size Very little, with low cost, low-power consumption, it is multi-functional the features such as.
Surface acoustic wave sensor meets the requirement of WSN nodes, and its size is small, can mass produce, low cost, low in energy consumption. The combination of sound surface probe and WSN will bring one of information Perception to change.
Traditional sensor is powered using dc source, if want to some in some are without the difficult environment of electricity, power supply Equipment or environment carry out condition monitoring, then setup state monitoring system is very difficult, while using wired mode connection system Each equipment, it will greatly bothered to construction wiring tape.Accordingly, it would be desirable to a kind of use self-powered wireless senser system System, solves the problems, such as without electricity or power supply difficulty, be difficult to carry out condition monitoring to target in the environment using wired energy supply.
General self energizing wireless sensing circuit, relies solely on the energy during energy harvester collects surrounding environment, however, all The energy in collarette border is typically all change, when ambient energy is smaller, i.e., is not enough to by the energy that energy harvester is collected When driving sensor, whole system will paralyse, and unpredictable consequence occur.
The content of the invention
It is an object of the invention to provide a kind of self energizing sensor-based system based on surface acoustic wave sensor and control method, Aim to solve the problem that without electricity or power supply it is difficult, be difficult to carry out condition monitoring to target in the environment using wired energy supply;It is existing from Energy supply wireless sensing circuit, relies solely on the energy during energy harvester collects surrounding environment, however, the energy one of surrounding environment As all be change, when ambient energy is smaller, i.e., by energy harvester collect energy be not enough to drive sensor when, it is whole Individual system will paralyse, the problem for unpredictable consequence occur.
The present invention is achieved in that a kind of self energizing sensor-based system based on surface acoustic wave sensor, described based on sound The self energizing sensor-based system of surface wave sensor includes:
Energy collecting system, is connected with signal transacting and radio frequency energy amount control circuit, for by the vibrational energy of ambient energy Amount and RF energy are converted to regulated power and drive working sensor, and the letter for being detected sensor by antenna using sensor Number it is transferred to signal transacting and radio frequency energy amount control circuit;
Signal transacting and radio frequency energy amount control circuit, are connected with cloud database, for the signal of sensor transmissions to be entered The microcontroller of a series for the treatment of of row, input signal treatment and radio frequency energy amount control circuit;Microcontroller on the one hand, in vibrational energy When amount deficiency but needs working sensor, the RF energy transmitter of control signal treatment and radio frequency energy amount control circuit is penetrated Frequency energy, energizing quantity collection system collecting energy;On the other hand, after microcontroller obtains sensor information, it is uploaded to high in the clouds number According to storehouse;
Cloud database, for high in the clouds data and intelligent terminal to be interacted.
Further, the energy collecting system includes:
Vibrational energy collector, is connected with energy management circuit, the vibrational energy for collecting surrounding;
RF energy collector, is connected with energy management circuit, for electric energy to be switched into electromagnetism by antenna in transmitting terminal Ripple, electric energy is switched in receiving terminal again by antenna by electromagnetic wave;
Energy management circuit, is connected with working sensor circuit, for by collected alternation, high frequency, unstable Electric energy is changed into direct current after rectification, storage, voltage stabilizing are processed, the electric energy that the energy of stabilization is used for sensor;
Working sensor circuit, is converted to oscillator signal, by antenna propagation to microcontroller by the heat transfer agent of sensor Device.
Further, RF energy collector uses RF energy collector Super-material antenna;The RF energy collector Super-material antenna uses the split ring resonator of Meta Materials, used as energy collection unit;The RF energy collector Meta Materials day The substrate of line uses polytetrafluoroethylglass glass fiber reinforcing material Rogers Duroid RT5880, and split ring resonator is using gold Au Material.
Further, vibrational energy collector includes:
Mass drives piezoelectric bending, and vibrational energy is switched into the piezo-electric effect part of electric energy;
Mass motion is moved with moving winding in the magnetic field that bar magnet is provided, and magnetic flux changes in coil, produces electricity The electromagnetic induction part of energy;
The piezo-electric effect part and electromagnetic induction part are electrically connected with energy management circuit.
Further, energy management circuit is by ac-to-dc rectifier, MPPT converters, energy storage circuit and voltage stabilizing electricity Road;
The ac-to-dc rectifier, is connected with MPPT converters, for the alternating current collected by energy harvester is whole It is direct current to flow;The ac-to-dc rectifier is made up of four diodes;
The MPPT converters, are connected with energy storage module, and the MPPT converters are by inductance L1, electric capacity C1, diode D5, metal-oxide-semiconductor Q, resistance R1 and MPPT control circuit composition;Inductance L1 is used to stop the friendship that the direct current after AC rectification contains Flow component is filtered;Electric capacity C1 is used to filter the alternating component on dc source;Diode D5 is used to ensure the sense of current; Resistance R1 is used for the current signal in circuit to be changed into voltage signal for MPPT control circuits;MPPT controls circuit by micro-control Device TIMSP430 processed and programmable pulse pio chip LTC6906 is constituted, and it is R1 both end voltages that the MPPT controls circuit input end Signal, output end is pwm signal;MPPT is used to make input source be operated near the maximum power point of MPPT, makes energy harvester More electric energy can be exported, the direct current of rectifier is effectively stored in super capacitor, so that sensor is used;Metal-oxide-semiconductor Q For controlling the pwm signal that circuit is exported to adjust the power output of MPPT converters according to MPPT, Q holds for MPPT converters Units;
Energy storage circuit, is connected with mu balanced circuit, and for the energy storage for circuit, the energy storage circuit is by super electricity Hold composition;
The mu balanced circuit is made up of voltage-stablizer LTC1877 and chip circumference outer member;The mu balanced circuit and sensing Device operating circuit is connected.
Further, the working sensor circuit is made up of Pierce oscillating circuits, driving and match circuit, antenna;Institute Pierce oscillating circuits are stated to be passed by gain amplifier U1, resistance R4, resistance R5, resistance R6, electric capacity C6, electric capacity C7, surface acoustic wave Sensor SAW, inductance L4 are constituted;The driving and match circuit are made up of power amplifier U2, inductance L3 and C5;
The surface acoustic wave sensor SAW is used to sense, and temperature, pressure physical signalling are converted to the electric signal of vibration;
Gain amplifier U1 amplifies for gain;Resistance R4, R5 and R6 are used to adjust the quiescent point of amplifier so that U1 is in and amplifies working condition;Inductance L4 is used to improve the frequency stability of oscillating circuit;Vin is the power supply electricity of oscillating circuit Pressure;On the one hand SAW resonator SAW constitutes the bandpass filter of pin network form with the electric capacity of C6, C7 two, on the other hand, On resonator resonant frequency, there is provided 180 degree phase shift, so that Pierce oscillating circuits meet amplitude balance and phase equilibrium Two conditions of vibration, and then entirely oscillating circuit vibration is got up;
The driving and match circuit are used to for transducing signal to propagate to antenna;Power amplifier U2 constitutes drive module; Inductance L3 and C5 constitute match circuit, for by the matches impedances of the impedance of antenna and amplifier.
Further, signal transacting and radio frequency energy amount control circuit be used for the signal from sensor after filtering, amplify, After Zero-IF demodulator, analog-to-digital conversion in incoming microprocessor, so as to reach the purpose of read sensor information;It is additionally operable to microprocessor Device control high power RF transmitter transmitting RF energy is used for sensor, in the case of low outside energy, is actively waken up and is passed Sense device working;
It is described by the signal from sensor after filtering, amplification, Zero-IF demodulator, incoming microprocessor after analog-to-digital conversion In, include so as to reach the method for purpose of read sensor information:
1) enter radio-frequency filter M1 after sensor signal is received through signal receiving antenna, filter mixed and disorderly outside useful band Signal;
2) low-noise preamplifier G1 is entered back into;
3) in entering back into zero intermediate frequency receiver Max7033, the zero intermediate frequency receiver Max7033 by low-converter J1, J2, Plate upper filter M2, M3 and low-noise amplifier G2, G3 are constituted;G1 signals out exist with signal source by the signal of orthogonalization Down-frequency conversion is carried out in low-converter J1, J2, the signal for obtaining enters high-order low-frequency filter on piece, obtains fundamental frequency signal; Because signal is weaker, the not up to range ability of AD analog-to-digital conversions strengthens signal by amplifier G2, G3;
4) AD is entered back into, is data signal by analog-signal transitions;
5) data signal enters microprocessor after, completes the task of read sensor information;
The microprocessor control high power RF transmitter transmitting RF energy is used for sensor, in low outside energy In the case of, the method for actively waking up working sensor includes:
(1) when artificial needs actively read sensing data, wake-up button is pressed, microcontroller sends startup transmitter The signal of work;
(2) signal enters in radio-frequency transmissions chip nRF905, and the nRF905 chips are used to turn into signal source, produces radio frequency letter Number;Afterwards, in radiofrequency signal ingoing power amplifier RF5110G, the RF5110G chips are used to strengthen the energy of radiofrequency signal;
(3) RF energy is launched by antenna.So as to realize actively waking up working sensor.
Another object of the present invention is to provide a kind of controlling party of the self energizing sensor-based system based on surface acoustic wave sensor Method, the control method of the self energizing sensor-based system based on surface acoustic wave sensor is comprised the following steps:
One) after system starts running, receiver is in holding state, and ambient energy is collected in energy collecting system operating;
Two) microcontroller judges whether that sensor has signal to transmit;
Three) in the case of having signal to transmit, microprocessor control receiver receives transducing signal, normal operation of sensor;
If four) sensor no signal enters receiver, represent that the electric energy that ambient energy deficiency or super capacitor are stored is inadequate, Then RF energy transmitter is in holding state;
Five) microcontroller determines whether artificial active trigger signal, if Triggerless, returns to the standby shape of receiver State, if there is trigger signal, into next step;
Six) microprocessor control RF energy transmitter transmitting RF energy;
Seven) microcontroller is determined whether artificially to terminate transmission signal, and previous step is returned if without transmission signal is terminated, after Supervention penetrates RF energy;
If eight) there is termination transmission signal, microcontroller sends signal, closes RF energy transmitter;
Nine) the standby transition of receiver is returned, restarts new circulation.
Another object of the present invention is to provide it is a kind of be provided with it is above-mentioned based on surface acoustic wave sensor self energizing sensing The tire pressure monitoring system of system.
Another object of the present invention is to provide it is a kind of be provided with it is above-mentioned based on surface acoustic wave sensor self energizing sensing The rail temperature monitoring system of system.
The self energizing sensor-based system based on surface acoustic wave sensor that the present invention is provided, energy content collector can be collected and shaken Energy and RF energy are used for sensor, can solve without electricity or power supply it is difficult, be difficult in the environment using wired energy supply The problem of condition monitoring is carried out to target.Additionally, the system contains radio frequency (Radio Frequency) energy harvester and radio frequency energy Amount transmitter, when extraneous (vibration) energy is inadequate, can launch RF energy by RF energy transmitter, be received for RF energy Storage collects energy and to sensor power.Based on this function, the present invention can actively wake up under extraneous energy starvation operating mode Working sensor, eliminates the risk of systemic breakdown.
The present invention can be used for tire pressure monitoring, as tire pressure monitoring system (TPMS);For rail temperature monitoring;For Engine temperature is monitored.
Brief description of the drawings
Fig. 1 is the self energizing sensor-based system schematic diagram based on surface acoustic wave sensor provided in an embodiment of the present invention.
Fig. 2 is energy collecting system schematic diagram provided in an embodiment of the present invention.
In figure:1st, mass;2nd, piezoelectric;3rd, coil and bar magnet;4th, RF energy collector Super-material antenna;5th, energy Buret manages circuit;6th, working sensor circuit;7th, antenna;8th, energy collecting system;9th, signal transacting and RF energy control electricity Road;10th, cloud database.
Fig. 3 is energy management circuit schematic diagram provided in an embodiment of the present invention.
Fig. 4 is working sensor module diagram provided in an embodiment of the present invention.
Fig. 5 is signal transacting provided in an embodiment of the present invention and RF energy electric operation control circuit figure.
Fig. 6 is vibrational energy collector schematic diagram provided in an embodiment of the present invention.
Fig. 7 is the control method stream of the self energizing sensor-based system based on surface acoustic wave sensor provided in an embodiment of the present invention Cheng Tu.
Fig. 8 is RF energy collector Super-material antenna schematic diagram provided in an embodiment of the present invention.
Specific embodiment
In order to make the purpose , technical scheme and advantage of the present invention be clearer, with reference to embodiments, to the present invention It is further elaborated.It should be appreciated that the specific embodiments described herein are merely illustrative of the present invention, it is not used to Limit the present invention.
Below in conjunction with the accompanying drawings and specific embodiment is described in detail to application principle of the invention.
As shown in figure 1, the self energizing sensor-based system based on surface acoustic wave sensor provided in an embodiment of the present invention, including:
Energy collecting system 8, is connected with signal transacting and radio frequency energy amount control circuit, for by the vibrational energy of ambient energy Amount and RF energy are converted to regulated power and drive working sensor, and the letter for being detected sensor by antenna using sensor Number it is transferred to signal transacting and radio frequency energy amount control circuit;
Signal transacting and radio frequency energy amount control circuit 9, are connected with cloud database, for the signal of sensor transmissions to be entered The microcontroller of a series for the treatment of of row, input signal treatment and radio frequency energy amount control circuit;Microcontroller on the one hand, in vibrational energy When amount deficiency but needs working sensor, the RF energy transmitter of control signal treatment and radio frequency energy amount control circuit is penetrated Frequency energy, energizing quantity collection system collecting energy;On the other hand, after microcontroller obtains sensor information, it is uploaded to high in the clouds number According to storehouse;
Cloud database 10, for high in the clouds data and intelligent terminal to be interacted.
Self energizing sensor-based system principle based on surface acoustic wave sensor provided in an embodiment of the present invention realizes surface acoustic wave The self energizing function of sensor-based system, specifically includes as follows:
1) the collected energy of the present invention includes vibrational energy and RF energy.
2) a vibrational energy part is converted to electric energy by the piezo-electric effect of piezoelectric, and another part passes through electromagnetic induction Be converted to electric energy.RF energy is converted to electric energy by RF energy collector.
3) energy for being gathered is processed as sensor power by electric power management circuit rectification, storage, voltage stabilizing etc..Sensor By heat transfer agent by array signal processing and control circuit.
4) signal that sensor is transmitted through is carried out a series for the treatment of, incoming microcontroller by signal processing circuit.Work as vibration When energy deficiency but needs working sensor, microprocessor control high power transmission device transmitting RF energy is adopted for RF energy Collector works, and collection RF energy drives working sensor.
5) after microcontroller obtains sensor information, cloud database is uploaded to, high in the clouds data can be entered with terminal such as mobile phone Row interaction, it is " Internet of Things " further to expand.
Advantages of the present invention is embodied in:Prior art self energizing wireless sensing circuit, relies solely on energy harvester collection Energy in surrounding environment, however, the energy of surrounding environment is typically all change, when ambient energy is smaller, i.e., by energy When the energy that amount collector is collected is not enough to drive sensor, whole system will paralyse, and unpredictable consequence occur.This hair It is bright containing radio frequency (Radio Frequency) energy harvester and RF energy transmitter, when extraneous (vibration) energy is inadequate, can RF energy is launched by RF energy transmitter, energy is collected and to sensor power for RF energy collector.Based on this Function, the present invention can actively wake up working sensor under extraneous energy starvation operating mode, eliminate the risk of systemic breakdown.
As shown in Fig. 2 energy collecting system:
Energy collecting system purpose is to be converted to surely ambient energy (such as vibrational energy and the actively RF energy of transmitting) Determine electric energy to be used for sensor.Implement process as follows:
1) vibrational energy can trigger coil and bar magnet in coil and bar magnet 3 directly mutually to move, and then cause coil Middle magnetic flux changes, and electromagnetic induction phenomenon occurs, so as to vibrational energy is converted into electric energy.
2) vibrational energy also results in the up-down vibration of mass 1, and mass vibration can cause the stress of piezoelectric 2, go out Existing piezo-electric effect, electric energy is converted to by vibrational energy.
3) RF energy collector is that electric energy is switched into electromagnetism by RF energy collector Super-material antenna 4 in transmitting terminal Ripple, electric energy is switched in receiving terminal again by RF energy collector antenna by electromagnetic wave, and the work of antenna is frequently in transfer process Rate must be identical with the frequency of received signal.
4) energy management circuit 5 be by collected alternation, high frequency, unstable electric energy by rectification, storage, surely The electric energy that the treatment such as pressure is changed into direct current, the energy of stabilization is used for sensor.
5) purpose of working sensor circuit 6 is that the heat transfer agent of SAW device is converted into oscillator signal, is passed through Antenna 7 propagates to microcontroller.
Piezoelectric can take PDMS (Polydimethylsiloxane, dimethyl silicone polymer) film in figure.Additionally, The working frequency of RF energy reception antenna must be identical with the frequency of transmitting radiofrequency signal.
As shown in figure 3, energy management circuit:
The circuit main purpose is that collected alternation, high frequency, unstable electric energy are passed through into rectification, storage, voltage stabilizing Deng the electric energy that treatment is changed into direct current, the energy of stabilization is used for sensor.The circuit is mainly made up of four parts, i.e. AC-DC Rectifier, MPPT (Maximum Power Point Tracking, MPPT maximum power point tracking) converter, energy storage circuit and Mu balanced circuit.Specifically effect is as follows for each component:
1) ac-to-dc rectifier:It is direct current that the module is act as the AC rectification collected by energy harvester. The module is made up of four diodes, and because diode has one-way conduction characteristic, alternating current is by the electricity after diode rectification Stream direction is the conducting direction of diode.Electric current flows into clockwise direction in Fig. 3.
2) MPPT converters:The converter is more crucial part in whole energy management circuit.The converter is by electricity Sense L1, electric capacity C1, diode D5, metal-oxide-semiconductor Q, resistance R1 and MPPT control circuit composition.Wherein inductance L1 plays filtering, Direct current after AC rectification contains AC compounent, and passing through for AC compounent can be stopped using inductance, (allows direct current to pass through, no Exchange is allowed to pass through) play a part of filtering., electric capacity C1 play a part of to filter the alternating component on dc source, diode D5 To ensure the sense of current.R1 is that the current signal in circuit is changed into voltage signal to be used for MPPT control circuits.MPPT is controlled Circuit is R1 both end voltage signals by microcontroller TIMSP430 and programmable pulse pio chip LTC6906, module input, It is output as PWM (Pulse-Width Modulation, pulsewidth modulation) signal.MPPT act as making input source be operated in it most Near high-power point, energy harvester is exported more electric energy, the direct current of rectifier is effectively stored in super electricity Rong Zhong, so that sensor is used.Metal-oxide-semiconductor Q act as controlling the pwm signal that circuit is exported to adjust MPPT converters according to MPPT Power output, Q for MPPT converters executive component.
3) energy storage circuit:The circuit is the accumulator of circuit, is made up of super capacitor.The electric capacity of the super capacitor The order of magnitude is farad (F), and voltage level is volt (V).
4) mu balanced circuit:Mu balanced circuit is made up of Linear Techn Inc. voltage-stablizer LTC1877 and chip circumference outer member. The input voltage range of the chip is 2.65V to 10V, is output as 3.3V, is steady a high efficiency, one chip, synchronous buck type Depressor, using a kind of constant frequency, current mode architecture.Additionally, the conversion efficiency of LTC1877 is very high, 95% is reached as high as, System power dissipation can be reduced.
As shown in figure 4, working sensor circuit:
The circuit purpose is gone out to make normal operation of sensor, and transducing signal being amplified by antenna propagation.The circuit It is made up of gain amplifier U1, resistance R1, surface acoustic wave sensor SAW, power amplifier U2, antenna and match circuit.Each unit Specifically effect is as follows for device:
1) surface acoustic wave sensor SAW plays sensing, and the physical signallings such as temperature, pressure can be converted to the telecommunications of vibration Number, sensor is resonant mode surface acoustic wave sensor, and its resonant frequency is in dependency relation with measured physical quantity.
2) sensor oscillator circuit selection Pierce pierce circuits, advantage is that reliability and stability are high.Wherein, gain Amplifier U1 plays gain amplification, and resistance R4, R5 and R6 adjust the quiescent point of amplifier so that U1 is in and amplifies work State.The frequency stability for acting as improving oscillating circuit of inductance L4, Vin is the supply voltage of oscillating circuit, surface acoustic wave On the one hand resonator constitutes the bandpass filter of pin network form with the electric capacity of C6, C7 two, on the other hand, is resonated frequently in resonator In rate, there is provided 180 degree phase shift.So that oscillating circuit meets two conditions of vibration, i.e. 1. amplitude balance 2. phase equilibrium, And then whole oscillating circuit vibration is got up.
3) drive and match circuit:The circuit purpose is that transducing signal is propagated into antenna.Drive module is by power amplification Device U2 is constituted, and match circuit is made up of inductance L3 and C5, by the impedance of antenna and the matches impedances of amplifier.
In the measurement data of surface acoustic wave oscillating circuit, the operating point of oscillating circuit is near 434MHz.
As shown in figure 5, signal transacting and radio frequency energy amount control circuit:
Signal transacting and the purpose of circuit is controlled to be:One, by the signal from sensor after filtering, amplify, zero intermediate frequency After demodulation, analog-to-digital conversion in incoming microprocessor, so as to reach the purpose of read sensor information.Two, microprocessor control is high Power radio frequency transmitter transmitting RF energy is used for sensor, in the case of low outside energy, actively wakes up working sensor. Implement step as follows:
Purpose one realizes step:
1) enter radio-frequency filter M1 after sensor signal is received through signal receiving antenna, filter mixed and disorderly outside useful band Signal.
2) low-noise amplifier must be used into low-noise preamplifier G1, G1 after, it is to avoid bring noise signal into, Influence system signal quality.
3) enter in zero intermediate frequency receiver Max7033 after, the principle of zero intermediate frequency receiver Max7033 is:By down coversion Device J1, J2, plate upper filter M2, M3 and low-noise amplifier G2, G3 composition.G1 signals out are with signal source by orthogonalization Signal down-frequency conversion is carried out in low-converter J1, J2, the signal for obtaining enter piece on high-order low-frequency filter, obtain base Frequency signal.Because signal is weaker, the range ability of not up to AD (analog-to-digital conversion), so as to increased amplifier G2, G3.Zero intermediate frequency Demodulation advantage is that IF signal frequency is zero, in the absence of image frequency, therefore in the absence of image frequency interference problem, it is not necessary to High q-factor bandpass filter, can very well realize single-chip integration, and receiver power consumption and interference are also reduced in addition.
4) enter AD after, be data signal by analog-signal transitions.
5) data signal enters microprocessor after, completes the task of read sensor information.
Purpose two realizes step:
1) when people needs actively to read sensing data, wake-up button is pressed, microcontroller sends startup transmitter work The signal of work.
2) signal enters in radio-frequency transmissions chip nRF905, and the chip act as turning into signal source, produces radiofrequency signal.It Afterwards, in radiofrequency signal ingoing power amplifier RF5110G, the chip act as strengthening the energy of radiofrequency signal.
3) RF energy is launched by antenna.So as to realize target two.
Surface acoustic wave sensor its part is made up of piezoelectric, reflecting grating, interdigital electrode, pad, wire.
The measurement data of the reflectance factor S11 of SAW device as vector network analyzer measure obtained by, the sound table Face wave resonant frequency is that near 432MHz, the design of oscillating circuit needs to be designed according to the frequency of oscillation of the device.
As shown in fig. 6, vibrational energy collector:
The energy harvester, piezoelectric can use PDMS.The energy harvester can reach the purpose for collecting vibrational energy. And vibrational energy point two parts are collected, i.e., 1. mass 1 drives the bending of piezoelectric 2, so as to piezo-electric effect occur, will vibrate Energy switchs to electric energy, and 2. mass motion is moved with moving winding in the magnetic field that permanent magnet 3 is provided, and magnetic flux becomes in coil Change, from electromagnetic induction effect, electric energy will be produced.
The output current of energy harvester and the data of output voltage are collected by data collecting card, are energy The output parameter of collector.
As shown in fig. 7, the control method of the self energizing sensor-based system based on surface acoustic wave sensor;
It is described in detail below:
1) after system starts running, receiver (containing microcontroller, signal processing circuit) is in holding state, collection of energy Ambient energy is collected in system operating;
2) microcontroller judges whether that sensor has signal to transmit;
3) in the case of having signal to transmit, microprocessor control receiver receives transducing signal, normal operation of sensor;
If 4) sensor no signal enters receiver, represent that the electric energy that ambient energy deficiency or super capacitor are stored is inadequate, Then RF energy transmitter is in holding state;
5) microcontroller determines whether artificial active trigger signal, if Triggerless, returns to the standby shape of receiver State, if there is trigger signal, into next step;
6) microprocessor control RF energy transmitter transmitting RF energy;
7) microcontroller is determined whether artificially to terminate transmission signal, and previous step is returned if without transmission signal is terminated, after Supervention penetrates RF energy;
If 8) there is termination transmission signal, microcontroller sends signal, closes RF energy transmitter;
9) the standby transition of receiver is returned, restarts new circulation.
As shown in figure 8, RF energy collector Super-material antenna application advantage:When emission of radio frequency signals source and antenna away from From farther out when, the efficiency of energy collection of ordinary antennas is not high.And using the split ring resonator of Meta Materials, as collection of energy list Unit, the collection efficiency of unit area is higher.(Meta Materials (meta-material) are the artificial materials with unusual electromagnetic property, Typically it is made up of the construction unit periodic arrangement much smaller than wavelength, such as there is the left hand material of negative index and negative magnetoconductivity simultaneously Material.) substrate of the antenna can use polytetrafluoroethylglass glass fiber reinforcing material Rogers Duroid RT5880.Opening resonance Ring can be using golden (Au) as material.
Electric field obtained from finite element analysis is carried out to the split ring resonator of Super-material antenna using simulation software to distribute, Electric field is stronger at the opening of split ring resonator, can from there gather electric energy.
Self energizing sensor-based system based on surface acoustic wave sensor and control method that the present invention is provided, energy content are collected Device, can collect vibrational energy and RF energy is used for sensor, can solve without electricity or power supply it is difficult, be difficult using wired confession The problem of condition monitoring is carried out in the environment of energy to target.Additionally, the system contains radio frequency (Radio Frequency) collection of energy Device and RF energy transmitter, when extraneous (vibration) energy is inadequate, can launch RF energy by RF energy transmitter, supply RF energy collector collects energy and to sensor power.Based on this function, the present invention can be in extraneous energy starvation operating mode It is lower actively to wake up working sensor, eliminate the risk of systemic breakdown.
Presently preferred embodiments of the present invention is the foregoing is only, is not intended to limit the invention, it is all in essence of the invention Any modification, equivalent and improvement made within god and principle etc., should be included within the scope of the present invention.

Claims (10)

1. a kind of self energizing sensor-based system based on surface acoustic wave sensor, it is characterised in that described based on surface acoustic wave sensing The self energizing sensor-based system of device includes:
Energy collecting system, is connected with signal transacting and radio frequency energy amount control circuit, for by the vibrational energy of ambient energy and RF energy is converted to regulated power and drives working sensor, and is passed by the signal that antenna detects sensor using sensor It is defeated by signal transacting and radio frequency energy amount control circuit;
Signal transacting and radio frequency energy amount control circuit, are connected with cloud database, for the signal of sensor transmissions to be carried out into one The microcontroller of series of processes, input signal treatment and radio frequency energy amount control circuit;Microcontroller on the one hand, in vibrational energy not When foot but needs working sensor, the RF energy transmitter transmitting radio frequency energy of control signal treatment and radio frequency energy amount control circuit Amount, energizing quantity collection system collecting energy;On the other hand, after microcontroller obtains sensor information, it is uploaded to cloud database;
Cloud database, for high in the clouds data and intelligent terminal to be interacted.
2. the self energizing sensor-based system of surface acoustic wave sensor is based on as claimed in claim 1, it is characterised in that the energy Collection system includes:
Vibrational energy collector, is connected with energy management circuit, the vibrational energy for collecting surrounding;
RF energy collector, is connected with energy management circuit, for electric energy to be switched into electromagnetic wave by antenna in transmitting terminal, Electromagnetic wave is switched to electric energy by receiving terminal again by antenna;
Energy management circuit, is connected with working sensor circuit, for by collected alternation, high frequency, unstable electric energy The electric energy that the energy for be changed into direct current after rectification, storage, voltage stabilizing are processed, stablizing is used for sensor;
Working sensor circuit, is converted to oscillator signal, by antenna propagation to microcontroller by the heat transfer agent of sensor.
3. the self energizing sensor-based system of surface acoustic wave sensor is based on as claimed in claim 2, it is characterised in that RF energy Collector uses RF energy collector Super-material antenna;RF energy collector Super-material antenna the opening using Meta Materials Mouth resonant ring, as energy collection unit;The substrate of the RF energy collector Super-material antenna uses polytetrafluoroethylene (PTFE) glass Glass fibre reinforced materials Rogers Duroid RT5880, split ring resonator uses gold Au materials.
4. the self energizing sensor-based system of surface acoustic wave sensor is based on as claimed in claim 2, it is characterised in that vibrational energy Collector includes:
Mass drives piezoelectric bending, and vibrational energy is switched into the piezo-electric effect part of electric energy;
Mass motion is moved with moving winding in the magnetic field that bar magnet is provided, and magnetic flux changes in coil, produces electric energy Electromagnetic induction part;
The piezo-electric effect part and electromagnetic induction part are electrically connected with energy management circuit.
5. the self energizing sensor-based system of surface acoustic wave sensor is based on as claimed in claim 2, it is characterised in that energy management Circuit is by ac-to-dc rectifier, MPPT converters, energy storage circuit and mu balanced circuit;
The ac-to-dc rectifier, is connected with MPPT converters, for being by the AC rectification collected by energy harvester Direct current;The ac-to-dc rectifier is made up of four diodes;
The MPPT converters, are connected with energy storage module, the MPPT converters by inductance L1, electric capacity C1, diode D5, Metal-oxide-semiconductor Q, resistance R1 and MPPT control circuit composition;Inductance L1 is used to stop the exchange that the direct current after AC rectification contains Component is filtered;Electric capacity C1 is used to filter the alternating component on dc source;Diode D5 is used to ensure the sense of current;Electricity Resistance R1 is used for the current signal in circuit to be changed into voltage signal for MPPT control circuits;MPPT controls circuit by microcontroller Device TIMSP430 and programmable pulse pio chip LTC6906 is constituted, and the MPPT controls circuit input end to believe for R1 both end voltages Number, output end is pwm signal;MPPT is used to make input source be operated near the maximum power point of MPPT, enables energy harvester More electric energy are enough exported, the direct current of rectifier is effectively stored in super capacitor, so that sensor is used;Metal-oxide-semiconductor Q is used In controlling the pwm signal that circuit is exported to adjust the power output of MPPT converters according to MPPT, Q is the execution of MPPT converters Element;
Energy storage circuit, is connected with mu balanced circuit, and for the energy storage for circuit, the energy storage circuit is by super capacitor group Into;
The mu balanced circuit is made up of voltage-stablizer LTC1877 and chip circumference outer member;The mu balanced circuit and sensor work Make circuit connection.
6. the self energizing sensor-based system of surface acoustic wave sensor is based on as claimed in claim 2, it is characterised in that the sensing Device operating circuit is made up of Pierce oscillating circuits, driving and match circuit, antenna;The Pierce oscillating circuits are put by gain Big device U1, resistance R4, resistance R5, resistance R6, electric capacity C6, electric capacity C7, surface acoustic wave sensor SAW, inductance L4 compositions;The drive Dynamic and match circuit is made up of power amplifier U2, inductance L3 and C5;
The surface acoustic wave sensor SAW is used to sense, and temperature, pressure physical signalling are converted to the electric signal of vibration;
Gain amplifier U1 amplifies for gain;Resistance R4, R5 and R6 are used to adjust the quiescent point of amplifier so that at U1 In amplification working condition;Inductance L4 is used to improve the frequency stability of oscillating circuit;Vin is the supply voltage of oscillating circuit;Sound On the one hand surface resonator SAW constitutes the bandpass filter of pin network form with the electric capacity of C6, C7 two, on the other hand, in resonance On device resonant frequency, there is provided 180 degree phase shift so that Pierce oscillating circuits meet amplitude balance and phase equilibrium vibration Two conditions, and then entirely oscillating circuit vibration is got up;
The driving and match circuit are used to for transducing signal to propagate to antenna;Power amplifier U2 constitutes drive module;Inductance L3 and C5 composition match circuits, for by the matches impedances of the impedance of antenna and amplifier.
7. the self energizing sensor-based system of surface acoustic wave sensor is based on as claimed in claim 1, it is characterised in that signal transacting And radio frequency energy amount control circuit be used for the signal from sensor after filtering, amplifications, Zero-IF demodulator, biography after analog-to-digital conversion In entering microprocessor, so as to reach the purpose of read sensor information;It is additionally operable to microprocessor control high power RF transmitter Transmitting RF energy is used for sensor, in the case of low outside energy, actively wakes up working sensor;
It is described by the signal from sensor after filtering, amplification, Zero-IF demodulator, after analog-to-digital conversion in incoming microprocessor, So as to the method for reaching the purpose of read sensor information includes:
1) enter radio-frequency filter M1 after sensor signal is received through signal receiving antenna, filter the mixed and disorderly letter outside useful band Number;
2) low-noise preamplifier G1 is entered back into;
3) enter back into zero intermediate frequency receiver Max7033, the zero intermediate frequency receiver Max7033 is by low-converter J1, J2, piece Wave filter M2, M3 and low-noise amplifier G2, G3 are constituted;G1 signals out are with signal source by the signal of orthogonalization in lower change Down-frequency conversion is carried out in frequency device J1, J2, the signal for obtaining enters high-order low-frequency filter on piece, obtains fundamental frequency signal;Due to Signal is weaker, not up to the range ability of AD analog-to-digital conversions, and signal is strengthened by amplifier G2, G3;
4) AD is entered back into, is data signal by analog-signal transitions;
5) data signal enters microprocessor after, completes the task of read sensor information;
The microprocessor control high power RF transmitter transmitting RF energy is used for sensor, in low outside energy situation Under, the method for actively waking up working sensor includes:
(1) when artificial needs actively read sensing data, wake-up button is pressed, microcontroller sends startup transmitter work Signal;
(2) signal enters in radio-frequency transmissions chip nRF905, and the nRF905 chips are used to turn into signal source, produce radiofrequency signal; Afterwards, in radiofrequency signal ingoing power amplifier RF5110G, the RF5110G chips are used to strengthen the energy of radiofrequency signal;
(3) RF energy is launched by antenna.So as to realize actively waking up working sensor.
8. a kind of control method of the self energizing sensor-based system based on surface acoustic wave sensor as claimed in claim 1, it is special Levy and be, the control method of the self energizing sensor-based system based on surface acoustic wave sensor is comprised the following steps:
One) after system starts running, receiver is in holding state, and ambient energy is collected in energy collecting system operating;
Two) microcontroller judges whether that sensor has signal to transmit;
Three) in the case of having signal to transmit, microprocessor control receiver receives transducing signal, normal operation of sensor;
If four) sensor no signal enters receiver, represent that the electric energy that ambient energy deficiency or super capacitor are stored is inadequate, then penetrate Frequency energy emitter is in holding state;
Five) microcontroller determines whether artificial active trigger signal, if Triggerless, returns to receiver holding state, If there is trigger signal, into next step;
Six) microprocessor control RF energy transmitter transmitting RF energy;
Seven) microcontroller is determined whether artificially to terminate transmission signal, and previous step is returned if without transmission signal is terminated, and continues to send out Penetrate RF energy;
If eight) there is termination transmission signal, microcontroller sends signal, closes RF energy transmitter;
Nine) the standby transition of receiver is returned, restarts new circulation.
9. it is a kind of be provided with described in claim 1 based on surface acoustic wave sensor self energizing sensor-based system tire pressure monitoring system System.
10. it is a kind of be provided with described in claim 1 based on surface acoustic wave sensor self energizing sensor-based system rail temperature Degree monitoring system.
CN201611089960.5A 2016-12-01 2016-12-01 Self-powered sensing system based on surface acoustic wave sensor and control method thereof Pending CN106712246A (en)

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CN113447079A (en) * 2021-06-29 2021-09-28 南昌路兴交通工程监理咨询有限公司 Bridge detecting system
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Application publication date: 20170524