CN201264489Y - Automotive tire pressure monitoring method based on tyre impedance - Google Patents

Automotive tire pressure monitoring method based on tyre impedance Download PDF

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Publication number
CN201264489Y
CN201264489Y CNU2008203011756U CN200820301175U CN201264489Y CN 201264489 Y CN201264489 Y CN 201264489Y CN U2008203011756 U CNU2008203011756 U CN U2008203011756U CN 200820301175 U CN200820301175 U CN 200820301175U CN 201264489 Y CN201264489 Y CN 201264489Y
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tire
saw resonator
impedance
module
pressure
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张向文
许勇
潘明
樊永显
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Guilin University of Electronic Technology
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Guilin University of Electronic Technology
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Abstract

The utility model discloses a vehicle tire pressure monitoring device based on the tire impedance. A sound surface wave resonator is embedded into the inside of the tire, and the tire capacity and the resistance which are made of tire rubber and steel wire are taken the external impedance load of the sound surface wave resonator. The changed of the tire impedance is caused by the change of the tire status, and the change of the resonance frequency of the sound surface wave resonator is caused by the change of the tire impedance. The resonance of the sound surface wave resonator is generated and the signal of resonance frequency is sent out without power and wire through an external pulse excitation, and therefore the testing of the tire status without power and wire can be achieved. In the testing process of the tire status, different steel wires and a plurality of sound surface wave resonators are connected and a plurality of sound wave resonators with different external impedance loads are formed. The status testing of tire pressure, temperature, wear, aging and so are can be achieved by using the combination of the resonance frequency of a plurality of sound surface wave resonators.

Description

Automobile tire pressure monitor based on the tire impedance
(1) technical field:
The utility model relates to a kind of vehicle safety travel monitoring device, particularly a kind of automobile tire pressure monitor based on the tire impedance.
(2) background technology:
In running car, tire blow-out is that all drivers worry the most and the most difficult prevention that it can cause or bring out serious traffic accident.Particularly when running at high speed, tire blow-out will be dangerous more, and the security expert points out, when the automobile speed per hour surpassed more than 160 kilometers, tire blow-out and the mortality that causes were almost near 100%.Therefore according to theoretical analysis, before the tire blow-out, the pressure of tire can occur unusually, the danger by can fundamentally avoiding tire blow-out to cause to the warning of the monitoring of tire pressure and abnormal condition.In addition, if the inflation pressure deficiency of tire, then tire drag increases, automobile fuel consumption increases, tyre surface abnormal wear aggravation simultaneously, cause tire to be scrapped in early days, therefore, the real-time monitoring of tire pressure and the warning of abnormal condition are had very important significance to safety, economy and the stability that improves automobile.
Existing tire pressure measurement method, the patent that is called " motor tire infrabar annunciator " as the name of CN209245 notification number, this patent is that sensor is fixed on direct contact and the measurement that realizes tire pressure and temperature on the wheel hub, but, this installation process more complicated, tire need be got on to fall into the fixing of line sensor from steel ring, fixed sensing takes place loosening in the long-time rotation of tire and vibration processes easily or comes off, tire when inclement weather and high-speed motion, the high temperature that inside tires forms, wet environment very easily reduces the performance of sensor even damages sensor.In addition, this method of measurement is owing to be installed in sensor the inside of tire, the power supply that need be able to power for a long time, the performance-oriented lithium battery power supply of general use, but the life-span of lithium cell is limited, and it is very inconvenient to change battery, and the lithium cell volume and weight is bigger, increased the dynamic load of tire rotation, the dynamical equilibrium of destructible tire, discarded battery also can cause the pollution of environment.
For fear of the sensor in the problem aspect the installation, 2005, be R.Matsuzakia and A.Todoroki in 2005 the 119th phases " Sensors and Actuators " the 323rd? publish an article on 31 pages " utilizing electric capacity and oscillating circuit to carry out the wireless measurement (Wireless Strain Monitoring of Tires Using ElectricalCapacitance Changes with an Oscillating Circuit) of squeegee action ", the tyre surface condensance variation that the tire pressure variation is caused first is converted into the frequency change wireless transmission and comes out, be about to tread of tyre rubber and steel wire and regard capacity cell as, rubber is dielectric material, steel wire is a conductive material, and rubber between the adjacent wires and steel wire can be formed a tire capacity cell together.In tire module, the variation of tire pressure causes the distortion of tire protector, distance between the tyre surface steel wire changes, the electric capacity of the cond of being made up of tyre surface steel wire and rubber changes, changes in capacitance process CR oscillator is converted into the variation of frequency, launches by the antenna of projector.Externally module receiver receives the frequency signal of projector emission, and calculates through frequency counter and to give computer and handle, and the variation of the survey frequency signal that obtains is converted into the variation of tire pressure, thereby realizes the wireless measurement of tire pressure.Though can save conventional tire pressure sensor like this, the various troubles that occurred when having avoided conventional sensors is installed, but when utilizing tire condensance and CR oscillator to carry out the wireless measurement of tire pressure, measurement signal needs power supply when emission, the performance-oriented lithium battery power supply of general use, therefore still there is the variety of issue that uses powered battery to exist in this tire condition method of measurement, in addition, CR oscillator and projector are made up of electronic components such as resistance and amplifiers, it is very big to carry out tyre surface embedding mounting hardness, and can influence tread of tyre elasticity and rigidity after installing.
(3) utility model content:
Technical problem to be solved in the utility model provides a kind of need not to use powered battery, the easy automobile tire pressure monitor based on the tire impedance of installation.
The utility model is for realizing the designed automobile tire pressure monitor based on the tire impedance of said method, comprise that the variation with caused tyre surface electric capacity of tire pressure and resistive impedance is converted into the tire module that the frequency change wireless transmission is come out, and find the solution the external module that tire pressure changes according to the frequency change that receives.Described external module is continued to use the external module formation that prior art is used always, and described each tire module comprises at least one SAW resonator, near-end antenna and the matched impedance that is embedded in the rubber for tire; One end of SAW resonator links to each other with public steel wire G in the tire protector rubber by matched impedance, and the other end is by lead and the bead wire S that is different from public steel wire G nLink to each other, also be connected to the near-end antenna between SAW resonator and matched impedance.The SAW resonator of tire module is in the excitation that is subjected to the RF pulse signal that external module sends, resonance takes place under the influence of tire pressure, and resonant frequency returning to external module is carried out frequency computation part, and then solve the pressure of tire by the near-end antenna.
Because the variation of tyre temperature can cause the skew of the center resonant frequency of SAW resonator, therefore in order to eliminate the influence of these factors, make that the result of a measurement of tire pressure is more accurate, need carry out Compensation of Measuring Error.As improvement, can also embed the SAW resonator group that links to each other and form by two SAW resonators with same structure and identical central resonant frequency in the rubber for tire of described tire module.The end that two SAW resonators join links to each other with public steel wire G by matched impedance, and one at the other two ends of SAW resonator group link to each other with public steel wire G by lead, and one by lead and the bead wire S that is different from public steel wire G nLink to each other, also be connected to the near-end antenna between SAW resonator and matched impedance.Because temperature traverse is the same to the influence of two SAW resonator center resonant frequency, therefore, utilize the resonant frequency of these two SAW resonators just can eliminate the influence of temperature, obtain correct tire pressure measurement value the SAW resonator center resonant frequency.
Be positioned at a plurality of SAW resonators and/or all shared matched impedance of SAW resonator group and the near-end antenna of same tire module.
Be positioned at the different SAW resonators of same tire module and/or the bead wire S that the SAW resonator group is connect nHave nothing in common with each other, promptly external tire impedance difference is found the solution other tire parameter that those can influence the tire pressure measurement result with this, as temperature, wearing and tearing and the degree of aging etc. of tire.According to the number of selected SAW resonator of the number of the required parameter of finding the solution and/or SAW resonator group, and make each SAW resonator and/or SAW resonator group have different center resonant frequency.Utilize the resonant frequency of 2n SAW resonator of the individual SAW resonator group of n (n 〉=3), according to tire parameter (as pressure and/or temperature and/or wearing and tearing and degree of aging etc.) and the relation of tire impedance and the relation of tire impedance and SAW resonator resonant frequency, can obtain multiple parameter (as pressure and/or temperature and/or wearing and tearing and the degree of aging etc.) information of tire simultaneously by data fusion method.
Described external module comprises interconnective far-end antenna and RF transceiver, frequency counter, microcontroller and power supply;
Far-end antenna and RF transceiver: be used for to SAW resonator and/or SAW resonator group emission RF pulse signal, and receive the resonant frequency impulse singla that SAW resonator and/or SAW resonator group are returned;
Frequency counter: be used for the resonant frequency that receives is calculated, and result of calculation is sent into microcontroller;
Microcontroller: be used to control the time and the frequency size of the mode of operation of far-end antenna and RF transceiver and/or emission RF pulse signal and/or receive the time of resonant frequency signal and find the solution concrete state (as pressure and/or temperature and/or wearing and tearing and the ageing state etc.) information of tire according to the relation between tire condition (as pressure and/or temperature and/or wearing and tearing and degree of aging etc.) and the SAW resonator resonant frequency.
The tricks of described RF transceiver and far-end antenna is identical with the number of tire module, the corresponding tire module of every suit RF transceiver and far-end antenna.
Described microcontroller also links to each other with memory device and/or warning device and/or read out instrument, and memory device is used to store the safe pressure scope of tire, pressure-frequency and/or temperature-frequency and/or wearing and tearing and aging-frequency relation and each tire pressure value and/or temperature and/or the wearing and tearing and degree of aging of measuring of tire; Warning device is used in the hypertonia of tire or crosses when hanging down, and sends alerting signal; Read out instrument is used for the force value of display of tyre and/or the state and/or the fault type of tire.
External module is according to the concrete state (as temperature and/or wearing and tearing and degree of aging etc.) of tire, utilize the pressure security scope of tire under different conditions (as temperature and/or wearing and tearing and degree of aging etc.) of memory stores, pass through intelligent inference, pressure security state to tire under the current state is made right judgement, if the hypertonia of tire or low excessively, microcontroller is given warning device give a signal and read out instrument give a signal, if the pressure state of tire is normal, microcontroller is only given the read out instrument give a signal.
The utility model realizes that according to the relation between the resonant frequency of the relation of the electric capacity of tire pressure and tire protector and resistive impedance and tire protector impedance and SAW resonator the passive and wireless of tire pressure detects, save conventional sensor, reduced cost; The tire module volume of monitoring system is very little, the anti-electromagnetic interference and the resistance to heat of the SAW resonator of tire module are all fine, can in tire production process, directly embed in the rubber that is installed in the tread of tyre steel wire floor problems such as the installation the problem includes: of having avoided the tire module of present system for monitoring pressure in tyre to be installed in tire tube valve position or wheel hub position problem, fixing and performance impact; Tire module adopts passive mode of operation, avoid using in the present system for monitoring pressure in tyre active sensor need use powered battery and limit the monitoring system problem and the battery pollution problem in service life, also avoided the problem that adopts active sensor hour wheel loose tool piece volume and weight to increase the dynamic load of tire rotation greatly in the present system for monitoring pressure in tyre and influence the dynamical equilibrium of tire.
(4) description of drawings:
Below in conjunction with the drawings and specific embodiments the utility model is further elaborated.
Fig. 1 is the structural representation of a kind of embodiment of the present utility model.
Fig. 2 is the workflow diagram of the external module of corresponding diagram 1.
Fig. 3 is the structural representation of the SAW resonator group Mn of another kind of embodiment of the present utility model.
Fig. 4 is for to be embedded in a plurality of SAW resonator group Mn bonded assembly scheme drawings as Fig. 3 at same tire.
Fig. 5 is the workflow diagram of the external module of corresponding diagram 4.
Description of drawings: 1, external module; 2, tire module; 3, substrate; 4, SAW resonator; 5, SAW resonator group.
(5) specific embodiment:
Embodiment 1:
Embodiment based on the automobile tire pressure monitor of tire impedance can be made up of as shown in Figure 1 at least one tire module 2 and external module 1.The tire module 2 that is positioned at different kinds of tyre comprises SAW resonator 4 that is embedded in tire protector steel wire floor rubber and steel wire, near-end antenna and the matched impedance that is attached thereto.SAW resonator 4 is made up of interdigital transducer and two duplicate parasites on substrate 3 and substrate 3 surfaces, and parasite is the both sides that are arranged in interdigital transducer of symmetry fully.One end of the interdigital transducer of SAW resonator 4 links to each other with matched impedance, should also link to each other the other end of the interdigital transducer of SAW resonator 4 and tyre surface steel wire S with the near-end antenna by end in addition nLink to each other.One end and the near-end antenna of matched impedance link together, and the other end connects public steel wire G.Public steel wire G is the direct coupled tyre surface steel wire of the interdigital transducer S that is different from SAW resonator 4 nAnother root steel wire.Steel wire is a conductive material, and rubber is dielectric material, and in addition, the carbon black that rubber contains is a conductive material, like this by tyre surface steel wire S n, public steel wire G and the rubber between them can form the electric capacity and the resistive impedance of tire, this tire electric capacity and resistive impedance can be regarded the external tire impedance load of SAW resonator 4 as.When the pressure of tire changes, bead wire S nAnd the distance between public steel wire G changes, bead wire S n, public steel wire G and rubber impedor electric capacity and the resistance formed changes, the impedance load of SAW resonator 4 changes, the resonant frequency of SAW resonator 4 changes.
External module 1 is made up of far-end antenna, RF transceiver, frequency counter, microcontroller, memory device, alarm display device and power supply, and power supply is generally the power supply of automobile.Owing to there are a plurality of tire modules 2, in order to carry out the differentiation of tire module 2, external module 1 can be provided with many cover RF transceivers and far-end antenna, its tricks is identical with the number of tire module 2, the corresponding tire module 2 of every suit transceiver and far-end antenna, and RF transceiver and antenna be installed on the screening hawk on tire top.Frequency counter, microcontroller, memory device and displaying alarm are installed in the operator's compartment, every suit far-end antenna and transceiver all are wired to the frequency counter and the microcontroller of external module 1, microcontroller links to each other with frequency counter, transceiver and displaying alarm, and memory device can be stored the safe pressure scope and the preceding tire pressure value of measuring several times of tire.
When the microcontroller of external module 1 after some RF transceivers send exomonental order, this RF transceiver sends the RF pulse signal identical with the center resonant frequency of SAW resonator 4 by far-end sky alignment tire module 2.The interdigital transducer of the near-end antenna direct connection SAW resonator 4 of tire module 2, SAW resonator 4 utilizes interdigital transducer that the radiofrequency signal that receives is converted into the surface acoustic wave on SAW resonator 4 substrates 3 surfaces, and surface acoustic wave is propagated between the interdigital transducer of SAW resonator 4 and parasite resonance is taken place.Electric capacity and resistive impedance that the external tire impedance that links to each other with SAW resonator 4 is a tire, the electric capacity of tire and resistive impedance are subjected to the influence of the factors such as pressure of tire, the resonant frequency of SAW resonator 4 is subjected to the influence of external tire impedance, therefore, the states such as pressure of tire can reflect by the resonant frequency of SAW resonator 4.The resonant frequency signal of SAW resonator 4 is converted into the electromagnetic pulse signal of same frequency by the interdigital transducer of SAW resonator 4, and this electromagnetic pulse signal is launched by the near-end antenna of tire module 2.
The transceiver of external module 1 is after having launched impulse singla, after the received pulse order that the microcontroller of receiving external module 1 sends, enter receiving condition, in case after receiving the impulse singla of corresponding tire module 2 transmissions, send the received pulse signal to calculating that frequency counter carries out impulse rate.The impulse rate that calculates is given microcontroller, microcontroller carries out the calculating of tire pressure according to the relation between the change of resonance frequency of tire pressure variation and SAW resonator 4, the safe range that 2 former the tire pressure signals of this tire module and the tire pressure of the tire pressure that calculates and memory stores changed compares then, utilize intelligent algorithm judge the pressure state of tire be too high, cross low or normal.If the tire pressure state is too high or too low, microcontroller is given the warning device give a signal, and warning device sends alerting signal; Simultaneously, microcontroller is given the read out instrument give a signal, the state of display of tyre and fault type, otherwise microcontroller is only given the read out instrument give a signal, demonstrates the force value of tire.
The time of the time of the microprocessor control RF transceiver of external module 1 and the mode of operation of far-end antenna and transmitter pulse signal, frequency and received pulse signal.Each emission or reception order can only send to a transceiver, and a transceiver job promptly can only be arranged each time.After the pressure measurement data of all tire modules 2 was all received, microcontroller was determined the time opening of measurement next time according to the pressure condition of tire.When the pressure anomaly of tire, should shorten the time between twice measurement, otherwise, can increase the time between twice measurement.
When having the individual tire module 2 of m (m〉1), as Fig. 2, the workflow of present embodiment external module 1 is as follows:
A) time T 2 of exomonental time T 1 of initialization and received pulse, the definition transceiver be numbered i (i=1~m, m are the number of tire module 2), and initialization i=1 changes step b) over to;
B) judge whether i surpasses m+1, promptly whether has detected all tire modules 2, if do not have, changes step c) over to, otherwise changes step d) over to;
C) microcontroller of external module 1 sends the transmitter pulse order to i transceiver, i transceiver passes through far-end antenna transmission RF pulse signal after receiving the transmitter pulse order, be T1 launch time, then, the microcontroller of external module 1 sends the received pulse order to i transceiver, after i transceiver received the received pulse order, the far-end antenna of i transceiver is in the received pulse signal condition, wait for and receive the resonant frequency signal pulse that tire module 2 returns, time of reception is T2, at last, i transceiver sent the impulse singla of receiving into frequency counter and carried out frequency computation part, and result of calculation is sent into microcontroller, microcontroller change according to the pressure of tire and the frequency change of SAW resonator 4 between relation find the solution the pressure of tire, i=i+1 changes step b) over to;
D) microcontroller of external module 1 is according to pressure change signal and 2 former the tire pressure signals of each tire module of memory stores and the safe range that tire pressure changes of m the tire module 2 that receives, utilize intelligent algorithm to carry out the intelligent decision of m tire pressure state, if the too high or hypotony of pressure state abnormal pressure of some tires, change step e) over to, if the pressure state of all tires is all normal, change step f) over to;
E) microcontroller of external module 1 sends alarm command to warning device, warning device sends alerting signal, microcontroller sends tire pressure status information and force value to read out instrument, read out instrument shows the pressure state of each tire, if pressure anomaly, the concrete state of display abnormality, if pressure is normal, only show force value, wait for interval time of measurement T3, change step a) over to;
F) microcontroller of external module 1 sends the concrete force value of each tire to read out instrument, and read out instrument shows the force value of each tire, waits for interval time of measurement T4 then, and T4 can change step a) over to greater than T3.
Embodiment 2:
Present embodiment is by embedding a plurality of SAW resonator groups 5 in inside tires, not only can obtain pressure, temperature, wearing and tearing and the ageing information of tire simultaneously, can also carry out the correct judgement of tire pressure safe condition according to the tire pressure, temperature, wearing and tearing and the ageing information that obtain.
The structure of the external module 1 of present embodiment is identical with embodiment 1, texture ratio embodiment 1 complexity of its tire module 2, and promptly each tire module 2 mainly is made up of SAW resonator group 5, near-end antenna and matched impedance.This SAW resonator group 5 is that two SAW resonators 4 with identical structure interconnect and form, the end that two SAW resonators 4 join links to each other with public steel wire G by matched impedance, also is connected to the near-end antenna between SAW resonator 4 and matched impedance.One at the other two ends of SAW resonator group 5 link to each other with public steel wire G by lead, promptly do not connect external tire impedance; One by lead and the bead wire S that is different from public steel wire G nLink to each other, promptly connect external tire impedance, as shown in Figure 3.
When the temperature traverse of inside tires, variation of temperature can cause the variation of SAW resonator 4 center resonant frequency, thereby causes measured error.The utility model can also utilize the SAW resonator 4 that does not connect external tire impedance to carry out Compensation of Measuring Error, because variation of temperature can influence the center resonant frequency of the SAW resonator 4 that connects external tire impedance equally.In addition, the structure and the center resonant frequency of these two SAW resonators 4 are identical, and environment of living in is also identical, and therefore, the frequency change that temperature traverse causes on these two SAW resonators 4 should be the same.So, utilize the frequency change of these two SAW resonators 4 just can eliminate the measured error that temperature traverse causes, thereby obtain correct tire pressure status information.
In addition, when utilizing SAW resonator group 5 to carry out tire pressure measurement, because the safe pressure scope difference of tire under different temperatures, tire is also different with safe pressure scope under the degree of aging in difference wearing and tearing, therefore, external module 1 also needs to obtain temperature information and the Tyte Wear and the ageing state information of inside tires in order to carry out the correct judgement of tire pressure safe condition.At this moment, for the influence to SAW resonator 4 center resonant frequency of the pressure, temperature, wearing and tearing and the ageing state information that obtain tire simultaneously and compensates, present embodiment is embedded in the individual SAW resonator group 5 with different center resonant frequency of n (n 〉=3) at same tire and realizes.As shown in Figure 4, in order to obtain more tire information simultaneously, this enforcement can be embedded in a plurality of SAW resonator groups 5 at same tire, the end that these SAW resonator groups 5 link to each other all links to each other with public steel wire G by same matched impedance, and at public steel wire G and the indirect same near-end antenna of matched impedance.Two residue ends of each SAW resonator group 5, an end of external impedance and different bead wire S nLink to each other, an end of cock wheel tire impedance does not all link to each other with public steel wire G.The external tire impedance end of each SAW resonator group 5 bonded assemblys bonded assembly bead wire S of institute nDifference, its center resonant frequency are also different, but they do not connect external tire impedance end and link to each other with public steel wire G all the time.Measure the change of resonance frequency of two SAW resonators 4 of each SAW resonator group 5 respectively, then the information of measuring is carried out tire pressure, temperature, wearing and tearing and the ageing state information that data fusion can obtain needs.External module 1 can be according to the concrete wearing and tearing and the ageing state of tire, and the temperature regime in the tire, utilize the pressure security scope of the tire of memory stores at different temperatures, different wearing and tearing and degree of aging, by intelligent inference, the pressure security state of tire under Current Temperatures and current wearing and tearing and the degree of aging is made right judgement.If the hypertonia of tire or low excessively, microcontroller is given the warning device give a signal, and warning device sends alerting signal; Simultaneously, microcontroller is given the read out instrument give a signal, the state of display of tyre and fault type, if the pressure state of tire is normal, microcontroller is only given the read out instrument give a signal, demonstrates the force value of tire.
Suppose that each the SAW resonator group 5 external tire impedance end that is embedded in the motor tire connect bead wire S respectively j(j=1,2,3 ... n), each SAW resonator group 5 has different center resonant frequency f J0(j=1,2,3 ... n), and will have certain difference between the center resonant frequency of each SAW resonator group 5, promptly the maximum that all is greater than external tire impedance of the difference between each SAW resonator group 5 center resonant frequency changes SAW resonator 4 resonant frequencys cause and changes.Center resonant frequency according to SAW resonator group 5, design SAW resonator group 5, matched impedance and near-end antenna under each frequency, matched impedance that links to each other with SAW resonator group 5 and near-end antenna all are the process optimal designs, under the condition that satisfies SAW resonator 4, matched impedance and near-end antenna tyre surface embedding installation, the capacity usage ratio of SAW resonator group 5, frequency stability, insertion loss and quality factor Combination property are best, the near-end antenna transmit and receive performance the best.
When the microcontroller of external module 1 after some transceivers send exomonental order, this transceiver is f by far-end antenna transmission frequency at first 10RF pulse signal, f 10Be the center resonant frequency of first SAW resonator group 5M1 of tire module 2, i.e. M 1The center resonant frequency of two SAW resonators 4.The near-end antenna of transceiver and the cooresponding tire module 2 of far-end antenna receives the RF pulse signal of emission therewith, two SAW resonators 4 of each SAW resonator group 5 of near-end antenna direct connection of tire module 2, the interdigital transducer of SAW resonator 4 is converted into surface acoustic wave with the RF pulse signal that receives and propagates on substrate 3 surfaces of SAW resonator 4, because first SAW resonator group 5M of tire module 2 1The center resonant frequency of two SAW resonators 4 consistent with the frequency of received pulse signal, therefore, at two SAW resonators 4 of this SAW resonator group 5 resonance take place.Suppose that the resonant frequency by a SAW resonator 4a who does not link to each other with the tire impedance of same SAW resonator group 5 is f 11, the resonant frequency of the SAW resonator 4b that another links to each other with the tire impedance is f 12Wherein surface resonator a can be subjected to f 12To the influence of tire internal temperature, temperature can cause the skew of this SAW resonator 4a center resonant frequency, supposes that the skew that causes is Δ f T1, so its resonant frequency is:
f 11=f 01+Δf T1 1
The SAW resonator 4b that links to each other with the impedance of tire, the pressure of tire, temperature, wearing and tearing and the aging variation that all can cause external tire impedance, the variation of external tire impedance causes this SAW resonator 4b change of resonance frequency again, is assumed to f 1(P, T, W).Tyre temperature causes the shifted by delta f of the center resonant frequency of SAW resonator 4b equally in addition T1, therefore, the resonant frequency of this SAW resonator 4b is:
f 12=f 01+f 1(P,T,W)+Δf T1 2
SAW resonator 4a and SAW resonator 4b are converted into self resonant frequency signal the electromagnetic pulse signal of same frequency respectively, and this electromagnetic pulse signal is launched by the antenna of tire module 2.The transceiver of external module 1 is after having launched impulse singla, after the received pulse order that the microcontroller of receiving external module 1 sends, enter receiving condition, behind the impulse singla that receives corresponding tire module 2 transmissions, the received pulse signal is sent to the calculating that frequency counter carries out impulse rate, utilize frequency counter to obtain frequency f respectively 11And f 12, give microcontroller with the frequency that obtains then.
Next, the microcontroller of external module 1 sends exomonental order to same transceiver once more, and this transceiver is f by far-end antenna transmission frequency 20RF pulse signal, f 20Center resonant frequency for second SAW resonator group 5 of tire module 2.Can obtain SAW resonator group 5M according to identical principle external module 1 2The resonant frequency f of two SAW resonators 4 21And f 22
Then, can obtain the resonant frequency signal of two SAW resonators 4 of other SAW resonator group 5 after the same method, the microcontroller of external module 1 is found the solution following formula on the basis of the frequency signal that obtains:
f 11 = f 01 + Δf T 1 f 12 = f 01 + f 1 ( P , T , W ) + Δf T 1 f 21 = f 02 + Δf T 2 f 22 = f 02 + f 2 ( P , T , W ) + Δf T 2 , n ≥ 3 · · · f n 1 = f 0 n + Δf Tn f n 2 = f 0 n + f n ( P , T , W ) + Δf Tn - - - 3
The method of finding the solution can adopt data fusion and intelligent algorithm, and therefore, external module 1 can obtain pressure, temperature, wearing and tearing and the ageing state information of tire.Utilize this method to measure the pressure of tire, temperature, when wearing and tearing and ageing information, the method of demarcating is the tire pressure of employing standard, temperature sensor and LCR tester to tire at different pressures, different temperatures, the impedance of different wearing and tearing and degree of aging is measured, the result that will measure compares with the frequency of utilizing method of measurement of the present utility model to measure then, obtain pressure-frequency, temperature frequency, the corresponding relation of wearing and tearing and aging frequency, then this corresponding relation is deposited in the memory device of external module 1, according to these corresponding relations, the microcontroller of external module 1 can solve concrete tire pressure according to the frequency signal that obtains, temperature, wearing and tearing and degree of aging.
The microcontroller of external module 1 is according to finding the solution tire pressure, temperature, wearing and tearing and the ageing state information that obtains, utilize the pressure security scope of the tire of memory stores at different temperatures, different wearing and tearing and degree of aging, by intelligent algorithm the pressure security state of tire tire under Current Temperatures and current wearing and tearing and degree of aging is made judgement, if the hypertonia of tire or low excessively, microcontroller is given the warning device give a signal, and warning device sends alerting signal; Simultaneously, microcontroller is given the read out instrument give a signal, the state of display of tyre and fault type, if the pressure state of tire is normal, microcontroller is only given the read out instrument give a signal, demonstrates the force value of tire.
The time of the time of the microprocessor control RF transceiver of external module 1 and the mode of operation of far-end antenna and transmitter pulse signal, frequency and received pulse signal.Each emission or reception order can only send to a transceiver, and a transceiver job promptly can only be arranged each time.After the measurement signal of all tire modules 2 was all received, microcontroller was determined the time opening of measurement next time according to the pressure state of tire.When the pressure anomaly of tire, should shorten the time between twice measurement, otherwise, can increase the time between twice measurement.
When existing the individual tire module 2 of m (m〉1) and each tire module 2 that the individual SAW resonator group 5 of n (n 〉=3) is arranged, as Fig. 5, the workflow of present embodiment external module 1 is as follows:
A) time T 2 of exomonental time T 1 of initialization and received pulse, the definition transceiver be numbered i (i=1~m, m are the number of tire module 2), and initialization i=1 changes step b) over to;
B) judge whether i surpasses m+1, promptly whether has detected all tire modules 2, if do not have, changes step c) over to, otherwise changes step g) over to;
C) definition SAW resonator group 5 be numbered j (j=1~n, n are the number of SAW resonator group 5), and initialization j=1 changes step d) over to;
D) judge whether j surpasses n+1, promptly whether has obtained the metrical information of all SAW resonator groups 5 of this tire module 2, if do not have, changes step e) over to, otherwise changes step f) over to;
E) microcontroller of external module 1 sends the transmitter pulse order to i transceiver, i transceiver passes through far-end antenna transmission RF pulse signal after receiving the transmitter pulse order, be T1 launch time, and transmitting frequency is the center resonant frequency f of j SAW resonator group 5 of tire module 2 0jThen, the microcontroller of external module 1 is sent out the received pulse order to i transceiver, after i transceiver received the received pulse order, the far-end antenna of i transceiver is in the received pulse signal condition, wait for receiving the resonant frequency signal pulse that tire module 2 returns, time of reception is T2, and is last, i transceiver sent the impulse singla of receiving into frequency counter and carried out frequency computation part, result of calculation is sent into microcontroller, and j=j+1 changes step d) over to;
F) utilize the corresponding relation of pressure-frequency, temperature frequency, wearing and tearing and the aging frequency of memory stores, according to the relation between pressure, temperature, wearing and tearing and the degree of aging of the survey frequency of n SAW resonator group 5 of tire module 2 and tire, find the solution concrete pressure, temperature, wearing and tearing and the degree of aging of tire by data fusion method, i=i+1 changes step b) over to;
G) microcontroller of external module 1 is according to pressure, temperature, wearing and tearing and the ageing state information of m the tire module 2 that receives, utilize the pressure security scope of the tire of memory stores at different temperatures, different wearing and tearing and degree of aging, by intelligent algorithm the pressure security state of m tire tire under Current Temperatures and current wearing and tearing and degree of aging is made judgement, if the too high or hypotony of pressure state abnormal pressure of some tires, change step h over to), if the pressure state of all tires is all normal, change step I over to);
H) microcontroller of external module 1 sends alarm command to warning device, warning device sends alerting signal, microcontroller sends tire pressure status information and force value to read out instrument, read out instrument shows the pressure state of each tire, if pressure anomaly, the concrete state of display abnormality, if pressure is normal, only show force value, wait for interval time of measurement T3, change step a) over to;
I) microcontroller of external module 1 sends the concrete force value of each tire to read out instrument, and read out instrument shows the force value of each tire, waits for interval time of measurement T4 then, and T4 can change step a) over to greater than T3.
The utility model is not limited only to the foregoing description; need only and be embedded in SAW resonator 4 or SAW resonator group 5, and the tire self capacity and the resistance of bead wire and rubber formation is just belonged to protection domain of the present utility model as its external impedance at rubber for tire.

Claims (6)

  1. [claim 1] is based on the automobile tire pressure monitor of tire impedance, comprise external module (1) and at least one tire module (2), it is characterized in that: described each tire module (2) comprises at least one SAW resonator (4), near-end antenna and the matched impedance that is embedded in the rubber for tire; One end of SAW resonator (4) links to each other with public steel wire G in the tire protector rubber by matched impedance, the other end links to each other with the bead wire Sn that is different from public steel wire G by lead, also is connected to the near-end antenna between SAW resonator (4) and matched impedance.
  2. [claim 2] automobile tire pressure monitor based on the tire impedance according to claim 1, it is characterized in that: described tire module (2) also comprises at least one SAW resonator group (5), this SAW resonator group (5) interconnects by two SAW resonators (4) with same structure and identical central resonant frequency and forms, the end that two SAW resonators (4) join links to each other with public steel wire G by matched impedance, also be connected to the near-end antenna between SAW resonator (4) and matched impedance, one at the other two ends of SAW resonator group (5) link to each other with public steel wire G by lead, and one links to each other with the bead wire Sn that is different from public steel wire G by lead.
  3. [claim 3] automobile tire pressure monitor based on the tire impedance according to claim 1 and 2 is characterized in that: described different SAW resonators (4) and/or shared matched impedance of SAW resonator group (5) and the near-end antenna that is positioned at same tire module (2).
  4. [claim 4] automobile tire pressure monitor based on the tire impedance according to claim 1 and 2, it is characterized in that: describedly be positioned at the different SAW resonators (4) of same tire module (2) and/or bead wire Sn that SAW resonator group (5) is connect has nothing in common with each other, promptly each SAW resonator (4) and/or SAW resonator group (5) have different external tire impedances.
  5. [claim 5] automobile tire pressure monitor based on the tire impedance according to claim 1 and 2 is characterized in that: described external module (1) comprises at least one interconnective far-end antenna and RF transceiver, frequency counter, microcontroller and power supply;
    Far-end antenna and RF transceiver: be used for to SAW resonator (4) and/or SAW resonator group (5) emission RF pulse signal, and receive the resonant frequency impulse singla that SAW resonator (4) and/or SAW resonator group (5) are returned;
    Frequency counter: be used for the resonant frequency that receives is calculated, and result of calculation is sent into microcontroller;
    Microcontroller: be used to control the time and the frequency size of the mode of operation of far-end antenna and RF transceiver and/or emission RF pulse signal and/or receive the time of resonant frequency signal and change the pressure of finding the solution tire according to survey frequency.
  6. [claim 6] automobile tire pressure monitor based on the tire impedance according to claim 5, it is characterized in that: the tricks of described RF transceiver and far-end antenna is identical with the number of tire module (2), the corresponding tire module (2) of every suit RF transceiver and far-end antenna.
CNU2008203011756U 2008-06-16 2008-06-16 Automotive tire pressure monitoring method based on tyre impedance Expired - Lifetime CN201264489Y (en)

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Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN101348059B (en) * 2008-06-16 2011-01-05 桂林电子科技大学 Automotive tire pressure monitoring method based on tyre impedance and apparatus thereof
CN104228477A (en) * 2013-06-07 2014-12-24 固特异轮胎和橡胶公司 Abradeable sensor system for tire wear monitoring
CN104280174A (en) * 2013-07-12 2015-01-14 上海仪电电子股份有限公司 Vehicle surface pressure detection system and method
CN104786752A (en) * 2015-04-07 2015-07-22 桂林电子科技大学 Intelligent tire pressure monitoring system based on structure electrons and implementation method of system
WO2016041391A1 (en) * 2014-09-19 2016-03-24 软控股份有限公司 Patch-type passive surface acoustic wave sensing device and intelligent tire
CN106274306A (en) * 2015-06-26 2017-01-04 奥特润株式会社 Device for monitoring tyre pressure based on tire characteristics and method thereof

Cited By (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN101348059B (en) * 2008-06-16 2011-01-05 桂林电子科技大学 Automotive tire pressure monitoring method based on tyre impedance and apparatus thereof
CN104228477A (en) * 2013-06-07 2014-12-24 固特异轮胎和橡胶公司 Abradeable sensor system for tire wear monitoring
CN104228477B (en) * 2013-06-07 2017-08-08 固特异轮胎和橡胶公司 For tire wear monitor can abrasion sensor system
CN104280174A (en) * 2013-07-12 2015-01-14 上海仪电电子股份有限公司 Vehicle surface pressure detection system and method
CN104280174B (en) * 2013-07-12 2016-10-05 上海仪电电子股份有限公司 A kind of surface of vehicle pressure detecting system and detection method
WO2016041391A1 (en) * 2014-09-19 2016-03-24 软控股份有限公司 Patch-type passive surface acoustic wave sensing device and intelligent tire
CN104786752A (en) * 2015-04-07 2015-07-22 桂林电子科技大学 Intelligent tire pressure monitoring system based on structure electrons and implementation method of system
CN104786752B (en) * 2015-04-07 2017-04-26 桂林电子科技大学 Intelligent tire pressure monitoring system based on structure electrons and implementation method of system
CN106274306A (en) * 2015-06-26 2017-01-04 奥特润株式会社 Device for monitoring tyre pressure based on tire characteristics and method thereof
CN106274306B (en) * 2015-06-26 2018-04-06 奥特润株式会社 Device for monitoring tyre pressure and its method based on tire characteristics

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