CN204650760U - A kind of wireless geomagnetism vehicle checker adopting interval conversion power supply pattern - Google Patents
A kind of wireless geomagnetism vehicle checker adopting interval conversion power supply pattern Download PDFInfo
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Abstract
The utility model discloses a kind of wireless geomagnetism vehicle checker adopting interval conversion power supply pattern, comprise connect successively battery supply, power management chip, the first power supply control circuit in parallel and the second power supply control circuit, microcontroller and radio receiving transmitting module; Described first power supply control circuit comprises the first power supply control chip, the first magnetoresistive transducer and the ADC module that connect successively, second power supply control circuit comprises the second power supply control chip, the second magnetoresistive transducer and the 2nd ADC module that connect successively, and described power supervisor is connected with described first magnetoresistive transducer by described first power supply control chip.Improve the accuracy of detection signal when vehicle arrives.
Description
Technical field
The utility model relates to road vehicle detection technique field, particularly relates to a kind of wireless geomagnetism vehicle checker adopting interval conversion power supply pattern.
Background technology
Road vehicle detection technique is one of gordian technique of intelligent transportation.Can be obtained the Real-Time Traffic Volume information in road a certain traffic section or a certain track by vehicle detection, these transport information contribute to road management, and person carries out communications policy, also contributes to traffic participant and carries out trip planning.
Current wagon detector (hereinafter referred to as " vehicle checker ") mainly comprises: loop sensors, video vehicle checker, microwave vehicle checker, earth magnetism vehicle checker etc.Wherein, loop sensors is applied to urban traffic intersection more, and accuracy of detection is high, good reliability, but installation and maintenance more complicated; Video vehicle checker is larger by the impact of weather, light; Microwave vehicle checker is applied to the vehicle speed measurement of fastlink more, easily by the interference of environment, easily causes undetected by occlusion.Earth magnetism vehicle checker based on magnetoresistive transducer utilizes vehicle iron-holder comparatively large, carries out vehicle detection by the change detecting vehicle arrival and surrounding's local space terrestrial magnetic field caused when leaving.The advantage of earth magnetism vehicle checker mainly not by weather environment impact, not by other occlusions impact, volume is little and construction and installation are simple.Along with the maturation gradually of magnetoresistive sensor technology and wireless short range communication technology etc., the wireless geomagnetism vehicle checker that can be used for road vehicle detection obtains certain investigation and application.One is had to the vehicle detection of the traffic section of multilane, usual earth magnetism vehicle checker is all embedded in the middle position in every bar track.
In the middle of traffic practical application, by installing the detection that multiple wireless geomagnetism vehicle checker and trackside wireless receiver just can realize a traffic section (many tracks).The data collected are sent to trackside receiver by vehicle checkers all in this traffic section.One group of wireless geomagnetism vehicle checker on a traffic section and trackside receiver constitute a communication control net.This communication control net is exactly in fact a small-sized radio sensing network (WSN, Wireless Sensor Network).WSN is the network system that multiple sensor node is formed by short-distance wireless communication mode, and it can realize the collection of field data in industry-by-industry, process and transmission.Each node of usual WSN is made up of a sensing module, radio receiving transmitting module, microcontroller (MCU), (group) battery.For two-way eight tracks and a vehicle checker is installed in every track, 8 vehicle checkers (i.e. sensing node) and 1 trackside receiver (i.e. Centroid) form a WSN simplified (star topology).Vehicle data is uploaded to trackside Centroid by wireless short range communication module by car test sensing node; Trackside Centroid also can by the control command of wireless short range communication module transmission to multiple or single car test sensing node in addition.
The function of wireless geomagnetism vehicle checker mainly contains vehicle and there is detection and Bus-Speed Monitoring, and when the road of the multilane of reality is applied, every bar track all needs at least to install a vehicle checker.There is the principle detected in vehicle: when vehicle is by vehicle checker, vehicle checker peripherally signal magnetic field changes, when after this change triggers sensor detection threshold, vehicle checker thinks have vehicle to pass through.The principle of Bus-Speed Monitoring is: lay the fixing magnetoresistive transducer of two distances at vehicle heading, obtains Vehicle Speed by calculating distance (distances between two magnetoresistive transducers) with the ratio of mistiming (vehicle is through the mistiming of these two sensors).Wherein there is detection and can complete based on a magnetoresistive transducer in vehicle, and the cooperation that the speed of a motor vehicle and vehicle commander detect needs two magnetoresistive transducers could realize.Therefore, there are two large class wireless geomagnetism vehicle checkers in actual applications:
(1) one class is 2 vehicle checkers that test the speed, and namely only installs a magnetoresistive transducer in single vehicle checker.When this kind of vehicle checker is installed on a track with single form, only exists for detecting vehicle, if will car speed be detected, then needing along vehicle heading, two these type of vehicle checkers to be installed in a track at certain intervals.
(2) another kind of is Single-point velocity determination vehicle checker, is namely provided with two magnetoresistive transducers in single vehicle checker.Like this, a track only needs installation vehicle checker can realize Bus-Speed Monitoring function.
Compared with 2 vehicle checkers that test the speed, the advantage of Single-point velocity determination vehicle checker is: because a track only needs installation vehicle checker, therefore have construction volume little, the feature that cost is low.
In use, under being all embedded in central road surface, if battery supply depleted of energy, the mode can only taking out car test node by excavating road surface changes battery to wireless geomagnetism vehicle checker.So in the use procedure of car test node, how can reduce the power consumption of car test node, the serviceable life extending battery just becomes crucial technology.And in earth magnetism vehicle checker equipment, the average power consumption of magnetoresistive transducer is maximum, therefore in practical application, the magnetoresistive transducer in vehicle checker is intermittent power supply, namely just powers to sensor in ADC sampling period.Because the sampling time length of ADC is fixing, therefore intermittent power supply frequency less (namely the intermittent power supply cycle is longer), the average power-on time of sensor is shorter, and corresponding average power consumption is lower.But line frequency must the realization of guarantee sampling functions consistent with the sample frequency of ADC, and ADC sample frequency is lower, then the accuracy of vehicle characteristics curve that obtains of sensor is lower.The vehicle that too low sample frequency can cause high speed to be passed through is undetected, and Bus-Speed Monitoring precision also can be caused to reduce.It is more obvious that the contradiction of this power consumption and accuracy of detection shows in Single-point velocity determination vehicle checker.This is that volume owing to will ensure equipment is little as far as possible, and two magnetoresistive transducer mounting distances of its inside are very near, the normally magnitude of 100mm.According to the measuring principle of magnetoresistive transducer, in order to ensure certain rate accuracy, just need the precision of two magnetic resistance detection curve eigenwert mistimings of guarantee.For the same speed of a motor vehicle, along with two magnetoresistive transducer space lengths reduce, the corresponding mistiming just reduces, and required sample frequency just must increase.And under magnetoresistive transducer is in the pattern of high-frequency power supply and sampling, power consumption will be very high, causes the battery life of car test node low, finally causes the Single-point velocity determination formula vehicle checker operational use time short always.
So, in the Single-point velocity determination wireless geomagnetism vehicle checker of prior art, due to two magnetoresistive transducer close together, cause problem conflicting between power consumption and accuracy of detection particularly outstanding.
Utility model content
The purpose of this utility model is to provide a kind of wireless geomagnetism vehicle checker adopting interval conversion power supply pattern, thus solves the foregoing problems existed in prior art.
To achieve these goals, the technical solution adopted in the utility model is as follows:
Adopt a wireless geomagnetism vehicle checker for interval conversion power supply pattern, comprise connect successively battery supply, power management chip, the first power supply control circuit in parallel and the second power supply control circuit, microcontroller and radio receiving transmitting module; Described first power supply control circuit comprises the first power supply control chip, the first magnetoresistive transducer and the ADC module that connect successively, second power supply control circuit comprises the second power supply control chip, the second magnetoresistive transducer and the 2nd ADC module that connect successively, described power supervisor is connected with described first magnetoresistive transducer by described first power supply control chip, a described ADC module is connected with described microcontroller, and described microcontroller is connected with described first power supply control chip by the first Energy control pin; Described power supervisor is connected with described second magnetoresistive transducer by described second power supply control chip, and described 2nd ADC module is connected with described microcontroller, and described microcontroller controls pin by second source and is connected with described second power supply control chip.
Further, described wireless geomagnetism vehicle checker also comprises the first high-speed equipment amplifier and the second high-speed equipment amplifier, the input end of described first high-speed equipment amplifier is connected with the signal output part of described first magnetoresistive transducer, and the output terminal of described first high-speed equipment amplifier is connected with the input end of a described ADC module; The input end of described second high-speed equipment amplifier is connected with the signal output part of described second magnetoresistive transducer, and the output terminal of described second high-speed equipment amplifier is connected with the input end of described 2nd ADC module.
Preferably, described microcontroller comprises the signal processing module and data processing module that connect successively according to signal transmission direction, described signal processing module respectively with a described ADC module and described 2nd ADC model calling, described data processing module is connected with described radio receiving transmitting module.
Preferably, described first magnetoresistive transducer is parallel with the travel direction of vehicle with the geometry line of described second magnetoresistive transducer, and at a distance of 120mm between described first magnetoresistive transducer and described second magnetoresistive transducer.
Preferably, described battery supply adopts 3.6 volts of lithium thionyl chloride cells, and described power management chip adopts LDO chip TLV70030D.
Preferably, described first power supply control chip and described second power supply control chip all adopt the metal-oxide-semiconductor FDN304P of P raceway groove.
Preferably, described first magnetoresistive transducer and described second magnetoresistive transducer all adopt AMR magnetoresistive transducer, and the chip of described magnetoresistive transducer adopts single-axis sensors HMC1021Z.
Preferably, described microcontroller adopts MSP430 chip series.
Preferably, described radio receiving transmitting module adopts CC1101 radio receiving transmitting module.
Preferably, described first high-speed equipment amplifier and described second high-speed equipment amplifier all adopt INA331 amplifier.
The beneficial effects of the utility model are: the vehicle checker that the utility model provides for Single-point velocity determination, microcontroller controls power supply control chip by Energy control pin, realize break-make and the break-make frequency change of magnetoresistive transducer and ADC module, and then achieve interval, the conversion power supply to magnetoresistive transducer.Low frequency intermittent power supply frequency is adopted, now only for the detection of vehicle existence when vehicle does not arrive; And when detecting that vehicle arrives, switch to high frequency intermittent line frequency at once, thus both ensure that the pinpoint accuracy realizing Bus-Speed Monitoring under high-frequency ADC sampling, can avoid again when vehicle does not arrive, adopt high-frequency intermittent power supply waste power consumption; And in order to ensure that power consumption is low as far as possible, no matter when high-frequency is powered or when low frequency is powered, all adopt intermittent power supply.Therefore, the vehicle checker that the present embodiment provides, by intermittent power supply and conversion power supply two approach, reduce power consumption, improve battery life, and then extend the operational use time of vehicle checker, and pass through conversion power supply, improve the accuracy of detection signal when vehicle arrives, preferably resolve problem conflicting between power consumption and Bus-Speed Monitoring accuracy.
Accompanying drawing explanation
Fig. 1 is the structural representation of the wireless geomagnetism vehicle checker that the utility model embodiment one provides;
Fig. 2 is the schematic diagram of the magnetoresistive transducer cycle intermittent power supply that the utility model embodiment one provides;
Fig. 3 is the method flow schematic diagram of the wireless geomagnetism vehicle checker interval conversion power supply that the utility model embodiment two provides;
Fig. 4 is the method flow schematic diagram of the wireless renewal of wireless geomagnetism vehicle checker MCU program that the utility model embodiment three provides;
Fig. 5 is the method flow schematic diagram of the wireless renewal of wireless geomagnetism vehicle checker MCU program that the utility model embodiment four provides;
Fig. 6 be a kind of vehicle of providing of the utility model embodiment five by time magnetoresistive transducer signal curve actual test pattern.
Embodiment
In order to make the purpose of this utility model, technical scheme and advantage clearly understand, below in conjunction with accompanying drawing, the utility model is further elaborated.Should be appreciated that embodiment described herein only in order to explain the utility model, and be not used in restriction the utility model.
Embodiment one
As shown in Figure 1, the utility model embodiment provides a kind of wireless geomagnetism vehicle checker adopting interval conversion power supply pattern, comprise connect successively battery supply, power management chip, the first power supply control circuit in parallel and the second power supply control circuit, microcontroller and radio receiving transmitting module; Described first power supply control circuit comprises the first power supply control chip, the first magnetoresistive transducer and the ADC module that connect successively, second power supply control circuit comprises the second power supply control chip, the second magnetoresistive transducer and the 2nd ADC module that connect successively, described power supervisor is connected with described first magnetoresistive transducer by described first power supply control chip, a described ADC module is connected with described microcontroller, and described microcontroller is connected with described first power supply control chip by the first Energy control pin; Described power supervisor is connected with described second magnetoresistive transducer by described second power supply control chip, and described 2nd ADC module is connected with described microcontroller, and described microcontroller controls pin by second source and is connected with described second power supply control chip.
In actual use, in order to reduce construction volume, reduce the destructiveness of road pavement, the magneto-resistive sensor device being arranged on track central authorities adopts powered battery, and by the mode of wireless short range communication, information of vehicles is transferred to roadside device.Roadside device will send the data center on backstage to by telecommunication technique after information of vehicles process.By the mode of powered battery and radio communication, just eliminate power cable and the communications cable burying underground on road surface.
But the delivery of battery is limited, the wireless geomagnetism vehicle checker provided in the utility model embodiment, the method of intermittent power supply and frequency-change sampling can be adopted, under the prerequisite reducing power consumption, also can improve the accuracy to Bus-Speed Monitoring, the practical work process of this wireless geomagnetism vehicle checker is:
Battery supply provides power supply for whole wireless geomagnetism vehicle checker, and power management chip is changed the voltage that battery provides, for wireless geomagnetism vehicle checker provides stable voltage.Magnetoresistive transducer is for gathering the signal of passing cars, and signal is sent to ADC module, signal is sent to microcontroller by ADC module, and the sensor signal of microcontroller to input carries out analyzing and processing, the judgement carried out vehicle arrival and leave, the fast isoparametric calculating of driving of going forward side by side.In addition, microcontroller controls power supply control chip by Energy control pin, performance period intermittent break-make and the change of line frequency, and then make power supply be magnetoresistive transducer and ADC module carry out resting period property, the power supply of frequency conversion.Work period of microprocessor controls magnetoresistive transducer power-up period and ADC module is synchronous, ensures only when ADC module is sampled to magnetoresistive transducer input signal, just powers to magnetoresistive transducer, and other times magnetoresistive transducer is powered and is in off state.Magnetoresistive transducer is in the working method of cycle intermittent power supply, as shown in Figure 2.In one cycle, the ratio of power-on time and turn-off time is less, and the average power consumption that magnetoresistive transducer is contributed is less.
The conversion power supply process of magnetoresistive transducer is specially, and signal is sent to microcontroller by ADC module by magnetoresistive transducer, after microcontroller receives signal, and judgement signal carried out vehicle arrival and left by the threshold value set in advance.If microcontroller is thought do not have vehicle, then by making the cycle intermittent power supply frequency of magnetoresistive transducer be in lower frequency to the control of power supply control chip, equipment is made to be in the work of more low-power consumption.Once microcontroller detects that vehicle arrives, then improve ADC sample frequency and corresponding magnetoresistive transducer line frequency, ensure next step degree of accuracy that speed of a motor vehicle is calculated.By this conversion power supply, ensure that and depositing in case without vehicle, the power consumption of magnetic resistance vehicle checker is lower.
Visible, the wireless geomagnetism vehicle checker that the utility model embodiment provides, power supply control chip is controlled by the Energy control pin of microcontroller, realize power supply break-make and the frequency change of magnetoresistive transducer and ADC module, and then realize interval conversion power supply, and no matter be in low frequency power supply situation or high frequency electric power thus supplied, all adopt intermittent power supply.So, compared with the working method of powering with lasting, same frequency, adopt the wireless geomagnetism vehicle checker that the utility model embodiment provides, by intermittent power supply and conversion power supply two approach, reduce power consumption, so greatly improve battery life, extend the operational use time of vehicle checker; In addition, by conversion power supply, also improve the accuracy that information of vehicles when vehicle arrives detects.Thus preferably resolve the problem that there is contradiction between energy consumption of the prior art and accuracy in detection.
In the present embodiment, described wireless geomagnetism vehicle checker also comprises the first high-speed equipment amplifier and the second high-speed equipment amplifier, the input end of described first high-speed equipment amplifier is connected with the signal output part of described first magnetoresistive transducer, and the output terminal of described first high-speed equipment amplifier is connected with the input end of a described ADC module; The input end of described second high-speed equipment amplifier is connected with the signal output part of described second magnetoresistive transducer, and the output terminal of described second high-speed equipment amplifier is connected with the input end of described 2nd ADC module.
In said structure, by arranging high-speed equipment amplifier between magnetoresistive transducer and ADC module, the signal that magnetoresistive transducer collects can be amplified, transferring to again in ADC module after amplification.
In the present embodiment, described microcontroller comprises the signal processing module and data processing module that connect successively according to signal transmission direction, described signal processing module respectively with a described ADC module and described 2nd ADC model calling, described data processing module is connected with described radio receiving transmitting module.
By adopting said structure, after the signal that two magnetoresistive transducers in wireless geomagnetism vehicle checker collect is sent to two corresponding ADC modules respectively, be sent to again in microcontroller, in the microcontroller, first signal is processed signal by signal processing module, and such as filtration waits process, then, processed again by data processing module, such as to the calculating etc. of the speed of a motor vehicle, vehicle commander, and by radio receiving transmitting module, information of vehicles is sent to drive test node.
Wherein, in signal processing module, two signals are processed respectively, calculate the speed of a motor vehicle or vehicle commander according to information such as the eigenwerts between two signals.
In the present embodiment, described first magnetoresistive transducer is parallel with the travel direction of vehicle with the geometry line of described second magnetoresistive transducer, and at a distance of 120mm between described first magnetoresistive transducer and described second magnetoresistive transducer.
Wherein, in the process that magnetoresistive transducer uses in wireless geomagnetism vehicle checker, if by a magnetoresistive transducer Embedded installation below a certain track of road, by adjustment sensor threshold value, then passing through of this track upper vehicle can only be detected, and the interference of fellow road-users can not be subject to.If a certain track is provided with the magnetoresistive transducer of two in a distance, then two sensor distance are exactly the speed of vehicle divided by the mistiming through two magnetoresistive transducers, if two sensor distance are much smaller than vehicle commander, then this speed can regard vehicle instantaneous velocity as; Compared with Vehicle length, sensor can regard a point as, then leaving sensor time with the arrival difference of sensor time and the product of the speed of a motor vehicle is exactly vehicle commander.
According to above-mentioned principle, in the present embodiment, the first magnetoresistive transducer is parallel with the travel direction of vehicle with the geometry line of the second magnetoresistive transducer, and at a distance of 120mm between described first magnetoresistive transducer and described second magnetoresistive transducer.
In the present embodiment, described battery supply adopts 3.6 volts of lithium thionyl chloride cells, and described power management chip adopts LDO chip TLV70030D, and described first power supply control chip and described second power supply control chip all adopt the metal-oxide-semiconductor FDN304P of P raceway groove; Described first magnetoresistive transducer and described second magnetoresistive transducer all adopt AMR magnetoresistive transducer, and the chip of described magnetoresistive transducer adopts single-axis sensors HMC1021Z, described microcontroller adopts MSP430 chip series, described radio receiving transmitting module adopts CC1101 radio receiving transmitting module, and described first high-speed equipment amplifier and described second high-speed equipment amplifier all adopt INA331 amplifier.
Wherein, battery input voltage is converted to 3 volts of stable voltages by LDO chip TLV70030D is that whole circuit is powered.
Magnetoresistive transducer mainly comprises giant magnetoresistance (GMR), anisotropic magnetoresistive (AMR), tunnel magnetoresistive (TMR).These three kinds of magnetoresistive transducers can sense that vehicle arrives the change of the signal magnetic field peripherally caused.In the present embodiment, adopt AMR magnetoresistive transducer.Magnetoresistive sensor chip selects the single-axis sensors HMC1021Z of HoneyWel l company, and this analog sensor has the response frequency of nanosecond, at least normally can work in the resting period of 5kHz powers.HMC1021Z is a Wheatstone bridge, and resistance is 1 kilo-ohm, powers for 3 volts, and the electric current of a sensor chip consumption is 3mA.In order to reduce working current, intermittent power supply control is carried out to magnetoresistive transducer.Not needing to turn off sensor power in the time of sampling to sensor.Power supply control chip adopts a kind of metal-oxide-semiconductor FDN304P of P raceway groove, and realize magnetoresistive transducer supply current break-make and control, this chip switch speed of response is nanosecond, can realize the high speed control system of switching on or off electricity of magnetoresistive transducer.And cut-off current extremely low (1uA), sensor low-power consumption when can ensure cut-off current.
In the present embodiment, the simulating signal that AMR sensor detects is sent in high-speed equipment amplifier.Due in order to reduce power consumption, magnetoresistive transducer can be in the duty of high speed break-make, output signal is also the high-frequency signal being at least 10kHz, therefore in the present embodiment, adopt the high-speed low-power-consumption instrumentation amplifier INA331 of TI company, this amplifier speed of response is also in nanosecond, ensures that the signal of 5kHz can not distortion.Microcontroller adopts the low-power chip MSP430 series of TI company, and radio receiving transmitting module is the CC1101 of TI company, works in 433MHz.
Embodiment two
As shown in Figure 3, the wireless geomagnetism vehicle checker utilizing the utility model embodiment one to provide carries out the method for interval conversion power supply, can comprise the steps:
S1, judges whether the first magnetoresistive transducer detects and if so, then forwards S2 to by the signal that vehicle arrives, otherwise, adopt first frequency intermittent power supply;
S2, adopt second frequency intermittent power supply, second frequency is higher than first frequency;
S3, judges whether the second magnetoresistive transducer detects and if so, then forwards S4 to by the signal that vehicle arrives, otherwise, find S6;
S4, judges whether the first magnetoresistive transducer or the second magnetoresistive transducer detect and if so, then forwards S5 to by the signal that vehicle leaves, otherwise, forward S7 to;
S5, calculates and process bicycle information, and enters next circulation;
S6, judges whether the second magnetoresistive transducer detects time-out, if so, then thinks that vehicle stops, and forwards S5 to, otherwise forward S2 to;
S7, judges whether the first magnetoresistive transducer or the second magnetoresistive transducer detect time-out, if so, then thinks that vehicle stops, and forwards S5 to, otherwise forward S4 to.
In order to reduce the power consumption of magnetoresistive transducer, extend the serviceable life of battery, in the present embodiment, adopt the mode of intermittent power supply, but, when the power-on time length of the magnetoresistive transducer required for ADC module is certain, intermittent power supply frequency is lower, and power supply is less with the time scale turned off, the power consumption of magnetoresistive transducer contribution is less, otherwise power supply is larger with the time scale turned off, the power consumption of magnetoresistive transducer contribution is larger.And adopt lower intermittent power supply frequency, in one-period, the time that magnetoresistive transducer is powered is short, the time turned off is long, although the power consumption of reducing, but, may cause within the time period turned off, vehicle passes through, thus make magnetoresistive transducer the information of vehicle cannot be detected, or survey by mistake, therefore, in order to improve the accuracy of measurement, in the present embodiment, when vehicle arrives, improve the intermittent power supply frequency of magnetoresistive transducer, as will be understood by the skilled person in the art, when intermittent power supply frequency is higher, when reaching certain value, the working method of power supply continuously can be regarded as, therefore, there will not be magnetoresistive transducer the information of vehicle cannot be detected, or situation about by mistake surveying.And under raising car test information accurately prerequisite, in order to reduce the power consumption of magnetoresistive transducer further, extend the serviceable life of battery, in the present embodiment, when vehicle does not arrive, use lower intermittent power supply frequency, but this line frequency ensures to be enough to the arrival information that vehicle can be detected.
Wherein, microcontroller is by controlling power supply control chip, realize the break-make of magnetoresistive transducer, when magnetoresistive transducer detects vehicle arrival information, and after signal is sent to microcontroller by ADC module, microcontroller is by controlling power supply control chip, realize the raising of intermittent power supply frequency, when magnetoresistive transducer detects the information that vehicle leaves, and after signal is sent to microcontroller by ADC module, microcontroller, by controlling power supply control chip, realizes the reduction of intermittent power supply frequency.
And no matter adopt great frequency, by microprocessor controls magnetoresistive transducer, under making it be in cycle intermittent power supply pattern, greatly reduce power consumption.
Wherein, described first frequency is 100Hz ~ 1kHz, and described second frequency is 1KHz ~ 10kHz.When vehicle does not arrive, adopt the intermittent power supply frequency of 100Hz ~ 1kHz, arrival vehicle being detected can be ensured; After vehicle arrives, adopt the intermittent power supply frequency of 1KHz ~ 10kHz, the accuracy in detection of the speed of a motor vehicle can be ensured.
Embodiment three
As shown in Figure 4, the wireless geomagnetism vehicle checker that the present embodiment provides the utility model embodiment one, carries out the method for the wireless renewal of MCU program, can comprise the steps:
A1, trackside node wireless broadcast MCU program enters the order upgrading waiting status;
A2, all wireless geomagnetism vehicle checkers receive MCU program enter upgrade waiting status order after, to drive test node send response, meanwhile, MCU program enters renewal waiting status;
A3, after trackside node receives the response of all wireless geomagnetism vehicle checkers transmission, according to equipment serial number, one by one to the order that each wireless geomagnetism vehicle checker transmission MCU program upgrades at once;
A4, each wireless geomagnetism vehicle checker arranges application program wireless renewal mark in Flash, and carries out equipment and restart.
Adopting said method, so that the later maintenance of wireless geomagnetism vehicle checker, when not taking out the wireless geomagnetism vehicle checker be embedded in below road, can complete the renewal of program code.
Embodiment four
After ensureing the failure of wireless geomagnetism vehicle checker application program update, wireless geomagnetism vehicle checker still can work, the wireless geomagnetism vehicle checker that the present embodiment provides for the utility model embodiment one, provide one section " start-up routine ", this program and application program, not in same code area, can work alone.After equipment is restarted, first perform this start-up routine, if find that Flash exists " application program is wireless, and renewal indicates ", then start application program in wireless renewal MCU.Otherwise, cancel and upgrading, the application program that normal execution is original.
As shown in Figure 5, concrete method can be:
In the method for the wireless renewal provided in embodiment three, also comprise the steps: after A4
B1, after equipment is restarted, judges whether the wireless renewal mark of application program exists, and if so, then forwards B2 to, otherwise, forward B5 to;
B2, sends the wireless update request of application program;
B3, waits for wireless receiving application program update code;
B4, judges that whether the stand-by period is more than three seconds, if so, then forwards B7 to, otherwise, judge whether to receive application program update code, if so, then forward B8 to, otherwise, forward B3 to;
B5, executive utility;
B6, judges whether to receive the wireless more newer command of application program, if so, then forwards A4 to, otherwise, forward B5 to;
B7, removes the wireless renewal mark of application program in Flash, then forwards B5 to;
B8, receives application program update code, and verifies, judge whether to receive successfully, if so, then forward B9 to, otherwise, forward B2 to;
B9, erasing application program source code, writes more fresh code carry out reader check, judges whether application program is updated successfully, if so, then forward B7 to, otherwise, forward B2 to.
Embodiment five
The interval conversion power supply method that the wireless geomagnetism vehicle checker adopting embodiment one to provide and embodiment two provide, in outfield inspection vehicle speed.
Wherein, the distance of the first magnetoresistive transducer and the second magnetoresistive transducer is set to 120mm; The geometry line of two magnetoresistive transducers is parallel with vehicle heading.Through the order of two magnetoresistive transducers in travelling according to vehicle, by the magnetoresistive transducer of most advanced for vehicle mistake, be labeled as the first magnetoresistive transducer, by the magnetoresistive transducer of vehicle back process, be labeled as the second magnetoresistive transducer.
Minibus (adopts the result that hand-held radar meter detects with 60km/h speed, this speedometer error is positive and negative 1km/h) by above two magnetoresistive transducers time, the time dependent actual curve of output voltage of two magnetoresistive transducers is as shown in Figure 6.In Fig. 6, curve 1 is the signal that the first magnetoresistive transducer detects, and curve 2 is the signal that the second magnetoresistive transducer detects.
First magnetoresistive transducer output voltage exceedes threshold value and namely shows that vehicle arrives.As can be seen from Figure 6, the background voltage of the first magnetoresistive transducer is 1.75V.If threshold value be change in voltage more than 0.25V, as shown in Figure 6, the first magnetoresistive transducer reaches threshold value (for 1.5V) in the moment zero.
Be that (namely in the intermittent power supply cycle, magnetoresistive transducer the shortest opening time of powering is 0.1ms, and now magnetoresistive transducer electric current is 3mA for the situation of 0.1ms for supply voltage 3V, magnetoresistive transducer resistance 1k Ω, ADC retention time of sampling; All the other time magnetoresistive transducers are powered shutoff, and electric current is close to zero), computing equipment power consumption:
(1) when ADC sample frequency and magnetoresistive transducer cycle, intermittent power supply frequency was 1kHz, in one-period, the average current of (1ms) magnetoresistive transducer is: 3mA*0.1/1=0.3mA
(2) when ADC sample frequency and magnetoresistive transducer cycle, intermittent power supply frequency was 5kHz, in one-period, the average current of (0.2ms) magnetoresistive transducer is: 3mA*0.1/0.2=1.5mA:
In both cases, calculating the speed of a motor vehicle by two magnetoresistive transducer vehicle characteristics value mistimings is:
(1) when not taking frequency conversion measure, when when namely vehicle arrives, sample frequency is still 1kHz, namely magnetoresistive transducer sampling interval is 1ms.Article two, eigenwert (the first peak value) mistiming of curve is 7ms.By calculating, obtaining device measuring speed is 61.7km/h.Absolute error is+1.7km/h, and relative error is (61.7-60)/60=+2.9%.
(2), when when vehicle arrives, sample frequency becomes 5kHz, namely magnetoresistive transducer sampling interval is 0.2ms.Article two, eigenwert (the first peak value) mistiming of curve is 7.2ms.By calculating, obtaining device measuring speed is 60km/h.Identical with radar meter testing result.
By in above-mentioned two kinds of situations when vehicle does not reach and when vehicle arrives, the power consumption calculated and the result of the speed of a motor vehicle, can find out, the interval conversion power supply method that the vehicle checker adopting embodiment one to provide and embodiment two provide, the Bus-Speed Monitoring result precision obtained is high, ensure that equipment power dissipation is lower when arriving without vehicle simultaneously.
Embodiment six
Wireless geomagnetism vehicle checker is by carrying out data interaction between radio receiving transmitting module and drive test Centroid, so, the power consumption of the radio receiving transmitting module in wireless geomagnetism vehicle checker is maximum, so, how to effectively reduce the power consumption of wireless geomagnetism vehicle checker, extend the serviceable life of battery, it is crucial that need the power consumption reducing radio receiving transmitting module.
The present embodiment provides a kind of method reducing the radio receiving transmitting module power consumption of wireless geomagnetism vehicle checker for the wireless geomagnetism vehicle checker that embodiment one provides, and comprising:
When wireless geomagnetism vehicle checker is in holding state, radio receiving transmitting module wakes up once at interval of the first setting-up time section, the accepting state of the first channel is entered after waking up, the activation command that wait-receiving mode trackside Centroid sends within the first accepting state time period of setting, if received, then wireless geomagnetism vehicle checker performs activation command and enters duty, otherwise wireless geomagnetism vehicle checker keeps holding state; The described first accepting state time period is greater than the frequency of described first channel;
When wireless geomagnetism vehicle checker is in running order, radio receiving transmitting module enters the second channel, all wireless geomagnetism vehicle checkers put in order according to track number, wake up successively, after waking up, in the data transmitting time of setting, complete data successively send, the data transmitting time sum of all wireless geomagnetism vehicle checkers equals the second setting-up time section; Each wireless geomagnetism vehicle checker wakes up once in each second setting-up time section;
After radio receiving transmitting module completes data transmission, the synch command that wait-receiving mode drive test Centroid sends within the second accepting state time period of setting or control command, if received, then wireless geomagnetism vehicle checker performs synch command or control command, radio receiving transmitting module enters dormant state, waits for and waking up next time; Otherwise radio receiving transmitting module directly enters dormant state, wait for and waking up next time.
In order to prevent from being in different conditions wireless geomagnetism vehicle checker between the air interference of air interference and dissimilar communication, in the present embodiment, choose two different frequencies, mark off two channels, be denoted as the first channel and the second channel respectively, and the activation command that the first channel sends for receiving drive test Centroid during holding state, be used for preventing from being formed with the wireless geomagnetism vehicle checker of duty disturbing; Second channel is used for the data transmission and reception Centroid control command of wireless geomagnetism vehicle checker to drive test Centroid.
Wireless geomagnetism vehicle checker has standby and work two states.
Holding state is state when dispatching from the factory, and now equipment only has unique ID number, not yet distributes track number.At holding state, the whole dormancy of all circuit of wireless geomagnetism vehicle checker equipment, close car test function (magnetoresistive transducer is in power supply off state), power consumption is extremely low.Wake up once every the first setting-up time section (such as 5 minutes) radio receiving transmitting module, the accepting state of the first channel is entered, the activation command that wait-receiving mode trackside Centroid sends within the first accepting state time period (such as 150ms) of setting after waking up.After this mode makes to dispatch from the factory, wireless geomagnetism vehicle checker consume battery power is extremely low, is convenient to long-time storage and transport, and does not produce interference to other wireless networks in transit; Can meet simultaneously wireless geomagnetism vehicle checker Embedded installation under road surface after, network inter-sync in 5 minutes and enter duty at most.
Duty refers to that wireless geomagnetism vehicle checker is transported to on-the-spot and after installation formal initiate mode.In working order, wireless geomagnetism vehicle checker has car test function, timing uploading data function, receives and implementation center's node orders function.Wireless geomagnetism vehicle checker is transformed into duty from holding state and is referred to as " activation ".Activation comprises that node car test function is enabled, node track number is distributed, multi-node wireless communication networks.
In actual use, wireless geomagnetism vehicle checker can enter duty from holding state in accordance with the following steps:
Step one, trackside Centroid sends an activation command at the first channel every (such as 100 milliseconds) at regular intervals, activation command comprise No. ID with the corresponding relation in track number, and time synchronizing signal.For the activation command of the first channel, be specify id command.Specific a group ID is only had just to perform this order.
Step 2, first whether wireless geomagnetism vehicle checker check containing self ID number in activation command, if not containing self ID number, then do not perform any order.If containing self ID number, then according to activation command configuration self track number and time, and enable car test function (the activation command transmission frequency due to drive test Centroid be 100 milliseconds once, and wireless geomagnetism vehicle checker radio receiving transmitting module keeps accepting state 150 milliseconds after waking up at every turn, therefore radio receiving transmitting module one receives an activation command surely after the first time period that interval sets is waken up).
In the utility model embodiment, after wireless geomagnetism vehicle checker enters duty, coarse grained time division multiplex can be adopted to ensure, and multiple wireless geomagnetism vehicle checker regularly can upload vehicle data.Uploaded a vehicle data for one minute, 1 minute is divided into n m second (namely each slot length is m second), each vehicle checker takies one of them time slot and sends data.N represents wireless geomagnetism vehicle checker capacity.
Wherein time slot is the data transmitting time of described setting.
The data transmitting time of described setting can be: the transmitting time of packet, resend time and protection sum interval time.
Such as, if the longest transmitting time of packet of a wireless geomagnetism vehicle checker is 1 second, do not confirm that the words of wrapping only are retransmitted once (1 second), add 1 second protection interval, can determine that the data transmitting time of slot length and described setting is 3s, namely each wireless geomagnetism vehicle checker only takies the time transmission data of 3s in 1min, after data are sent completely, within the regular hour, (such as 100ms) does not receive other control command or synch command, then directly can enter dormant state, until enter next 1min, even if after data are sent, have received other control command or synch command, after forward command, also dormant state can be entered, until enter next 1min.So, even if wireless geomagnetism vehicle checker in working order under, radio receiving transmitting module transmission data and real time of forward command also very short, greatly reduce power consumption.
The data transmitting time of described setting can also be: the second setting-up time section divided by wireless geomagnetism vehicle checker number, the result obtained.
Such as, in earth magnetism is wireless vehicle checker, have 4 wireless geomagnetism vehicle checkers, then 1 minute can be divided into 4 15 seconds.Then within the time of 1min, the slot length that each wireless geomagnetism vehicle checker takies is 15 seconds.For 1 second long packet, confirm bag if do not received, in these 15 seconds, wireless geomagnetism vehicle checker packet just can be retransmitted repeatedly.
In practical operation, can be according to the actual requirements, above-mentioned any one mode is adopted to determine the slot length that a wireless geomagnetism vehicle checker takies within the regular hour, track number and timeslot number one_to_one corresponding, by distributing track number to wireless geomagnetism vehicle checker, the slot index that wireless geomagnetism vehicle checker takies can be determined.
In a preferred embodiment of the present utility model, described first setting-up time section can be 5min, the frequency of described first channel can be 100ms, the described first accepting state time period can be 150ms, described second setting-up time section can be 1min, the described second accepting state time period can be 100ms, and described activation command comprises the corresponding relation in No. ID, wireless geomagnetism vehicle checker and track number, and time synchronizing signal.
Adopt the method for radio receiving transmitting module power consumption in above-mentioned reduction wireless geomagnetism vehicle checker, the communication of whole wireless geomagnetism vehicle checker can be realized as follows:
(1) for mounted wireless geomagnetism vehicle checker device id number, Centroid issues activation command (wireless geomagnetism vehicle checker wireless module is waken up and once received wait 150 milliseconds for 5 minutes) with 100 milliseconds of frequencies once at the first channel, the wireless geomagnetism vehicle checker making Embedment and installation good networks (after time synchronized, track number is exactly the communication time slot number of wireless geomagnetism vehicle checker).
(2) after wireless geomagnetism vehicle checker enters duty, Centroid and wireless geomagnetism vehicle checker are switched to " the second channel ".Wherein, trackside Centroid switches to passive reception data mode from initiatively sending activation command state, waits for the data upload of multiple wireless geomagnetism vehicle checker; Wireless geomagnetism vehicle checker switches to every 1 minute active upload vehicle data state from the state to be activated such as passive.Wireless geomagnetism vehicle checker radio receiving transmitting module is waken up once according to timeslot number is per minute and sends data.According to on-site wireless environment and actual demand, the unresponsive sending times of trackside Centroid can be configured.Usually, after power consumption and data transmission credibility balance, sending times is 1 time.
(3) at the second channel, wireless geomagnetism vehicle checker enters accepting state after sending data at once, wait for that 100 milliseconds with the synch command or other control commands of observing whether to have Centroid to send, if without, radio receiving transmitting module enters dormant state at once.
(4) at the second channel, every 10 minutes, trackside Centroid is unified transmission temporal information and is carried out time synchronized.Prevent the skew that wireless geomagnetism vehicle checker clock causes for a long time.
In above-mentioned communication plan, radio communication load is nearly all valid data, and waste power consumption is few.
By adopting technique scheme disclosed in the utility model, obtain effect useful as follows: the vehicle checker that the utility model provides for Single-point velocity determination, microcontroller controls power supply control chip by Energy control pin, realize break-make and the break-make frequency change of magnetoresistive transducer and ADC module, and then achieve interval, the conversion power supply to magnetoresistive transducer.Low frequency intermittent power supply frequency is adopted, now only for the detection of vehicle existence when vehicle does not arrive; And when detecting that vehicle arrives, switch to high frequency intermittent line frequency at once, thus both ensure that the pinpoint accuracy realizing Bus-Speed Monitoring under high-frequency ADC sampling, can avoid again when vehicle does not arrive, adopt high-frequency intermittent power supply waste power consumption; And in order to ensure that power consumption is low as far as possible, no matter when high-frequency is powered or when low frequency is powered, all adopt intermittent power supply.Therefore, the vehicle checker that the present embodiment provides, by intermittent power supply and conversion power supply two approach, reduce power consumption, improve battery life, and then extend the operational use time of vehicle checker, and pass through conversion power supply, improve the accuracy of detection signal when vehicle arrives, preferably resolve problem conflicting between power consumption and Bus-Speed Monitoring accuracy.
Each embodiment in this instructions all adopts the mode of going forward one by one to describe, and what each embodiment stressed is the difference with other embodiments, between each embodiment identical similar part mutually see.
Those skilled in the art it should be understood that the sequential of the method step that above-described embodiment provides can carry out accommodation according to actual conditions, also can carry out according to actual conditions are concurrent.
The hardware that all or part of step in the method that above-described embodiment relates to can carry out instruction relevant by program has come, described program can be stored in the storage medium that computer equipment can read, for performing all or part of step described in the various embodiments described above method.Described computer equipment, such as: personal computer, server, the network equipment, intelligent mobile terminal, intelligent home device, wearable intelligent equipment, vehicle intelligent equipment etc.; Described storage medium, such as: the storage of RAM, ROM, magnetic disc, tape, CD, flash memory, USB flash disk, portable hard drive, storage card, memory stick, the webserver, network cloud storage etc.
Finally, also it should be noted that, in this article, the such as relational terms of first and second grades and so on is only used for an entity or operation to separate with another entity or operational zone, and not necessarily requires or imply the relation that there is any this reality between these entities or operation or sequentially.And, term " comprises ", " comprising " or its any other variant are intended to contain comprising of nonexcludability, thus make to comprise the process of a series of key element, method, commodity or equipment and not only comprise those key elements, but also comprise other key elements clearly do not listed, or also comprise by the intrinsic key element of this process, method, commodity or equipment.When not more restrictions, the key element limited by statement " comprising ... ", and be not precluded within process, method, commodity or the equipment comprising described key element and also there is other identical element.
The above is only preferred implementation of the present utility model; it should be pointed out that for those skilled in the art, under the prerequisite not departing from the utility model principle; can also make some improvements and modifications, these improvements and modifications also should look protection domain of the present utility model.
Claims (10)
1. adopt a wireless geomagnetism vehicle checker for interval conversion power supply pattern, it is characterized in that, comprise connect successively battery supply, power management chip, the first power supply control circuit in parallel and the second power supply control circuit, microcontroller and radio receiving transmitting module; Described first power supply control circuit comprises the first power supply control chip, the first magnetoresistive transducer and the ADC module that connect successively, second power supply control circuit comprises the second power supply control chip, the second magnetoresistive transducer and the 2nd ADC module that connect successively, described power supervisor is connected with described first magnetoresistive transducer by described first power supply control chip, a described ADC module is connected with described microcontroller, and described microcontroller is connected with described first power supply control chip by the first Energy control pin; Described power supervisor is connected with described second magnetoresistive transducer by described second power supply control chip, and described 2nd ADC module is connected with described microcontroller, and described microcontroller controls pin by second source and is connected with described second power supply control chip.
2. the wireless geomagnetism vehicle checker adopting interval conversion power supply pattern according to claim 1, it is characterized in that, described wireless geomagnetism vehicle checker also comprises the first high-speed equipment amplifier and the second high-speed equipment amplifier, the input end of described first high-speed equipment amplifier is connected with the signal output part of described first magnetoresistive transducer, and the output terminal of described first high-speed equipment amplifier is connected with the input end of a described ADC module; The input end of described second high-speed equipment amplifier is connected with the signal output part of described second magnetoresistive transducer, and the output terminal of described second high-speed equipment amplifier is connected with the input end of described 2nd ADC module.
3. the wireless geomagnetism vehicle checker adopting interval conversion power supply pattern according to claim 1, it is characterized in that, described microcontroller comprises the signal processing module and data processing module that connect successively according to signal transmission direction, described signal processing module respectively with a described ADC module and described 2nd ADC model calling, described data processing module is connected with described radio receiving transmitting module.
4. the wireless geomagnetism vehicle checker adopting interval conversion power supply pattern according to claim 1, it is characterized in that, described first magnetoresistive transducer is parallel with the travel direction of vehicle with the geometry line of described second magnetoresistive transducer, and at a distance of 120mm between described first magnetoresistive transducer and described second magnetoresistive transducer.
5. the wireless geomagnetism vehicle checker adopting interval conversion power supply pattern according to claim 1, it is characterized in that, described battery supply adopts 3.6 volts of lithium thionyl chloride cells, and described power management chip adopts LDO chip TLV70030D.
6. the wireless geomagnetism vehicle checker adopting interval conversion power supply pattern according to claim 1, it is characterized in that, described first power supply control chip and described second power supply control chip all adopt the metal-oxide-semiconductor FDN304P of P raceway groove.
7. the wireless geomagnetism vehicle checker adopting interval conversion power supply pattern according to claim 1, it is characterized in that, described first magnetoresistive transducer and described second magnetoresistive transducer all adopt AMR magnetoresistive transducer, and the chip of described magnetoresistive transducer adopts single-axis sensors HMC1021Z.
8. the wireless geomagnetism vehicle checker adopting interval conversion power supply pattern according to claim 1, it is characterized in that, described microcontroller adopts MSP430 chip series.
9. the wireless geomagnetism vehicle checker adopting interval conversion power supply pattern according to claim 1, it is characterized in that, described radio receiving transmitting module adopts CC1101 radio receiving transmitting module.
10. the wireless geomagnetism vehicle checker adopting interval conversion power supply pattern according to claim 2, it is characterized in that, described first high-speed equipment amplifier and described second high-speed equipment amplifier all adopt INA331 amplifier.
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| CN104900068A (en) * | 2015-06-04 | 2015-09-09 | 交通运输部科学研究院 | Vehicle detector, method for intermittent and variable-frequency power supply, and method for reducing power consumption of wireless transceiver module |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN104900068A (en) * | 2015-06-04 | 2015-09-09 | 交通运输部科学研究院 | Vehicle detector, method for intermittent and variable-frequency power supply, and method for reducing power consumption of wireless transceiver module |
| CN107134151A (en) * | 2016-02-29 | 2017-09-05 | 胡睿 | Using NFC technique and the method for geomagnetic type vehicle checker data interaction |
| CN106060687A (en) * | 2016-06-08 | 2016-10-26 | 钰太芯微电子科技（上海）有限公司 | Multi-mode microphone power supply system |
| CN106128118A (en) * | 2016-06-08 | 2016-11-16 | 青岛交通科技信息有限公司 | A kind of wireless vehicle detecting system |
| CN106060687B (en) * | 2016-06-08 | 2024-05-17 | 钰太芯微电子科技（上海）有限公司 | Multi-mode microphone power supply system |
| CN106355898A (en) * | 2016-11-04 | 2017-01-25 | 南京理工大学 | Method and device for speed measurement based on geomagnetic sensing |
| WO2020006925A1 (en) * | 2018-07-05 | 2020-01-09 | 南京理工大学 | Vehicle detection method based on uniaxial geomagnetic sensor |
| US11373523B2 (en) | 2018-07-05 | 2022-06-28 | Nanjing University Of Science And Technology | Method for vehicle detection based on single-axis geomagnetic sensor |
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