CN101173986B - Ultrasonic distance measuring apparatus without blind zone - Google Patents
Ultrasonic distance measuring apparatus without blind zone Download PDFInfo
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Abstract
The invention relates to an ultrasonic range finder without blind areas, which comprises an ultrasonic wave transmitter module, an ultrasonic receiver module, a signal amplifier module, a signal processor module, a signal storage and control module, a waveform adjuster module and a signal compensation module; wherein, the transmitter module is used to transmit ultrasonic waves to the object under test, and the receiver module is used to receive the echoes reflected by the object to be tested; the amplifier module is electrically connected with the receiver module and is intended to amplify the echoes, and the signal processor module is connected with the signal amplifier module and used to calculate the initial range value. The signal storage and control module is connected with the signal processor module and utilized to record the initial range value and control the output of the ultimate range value; the waveform adjuster module is connected with and controlled by the signal storage and control module; and is used for adjusting the waveforms of ultrasonic waves transmitted by the transmitter module at real time. Moreover, the signal compensation module is connected with the signal storage and control module. The invention has the advantages of large range with the measuring distance up to 10 m, no blind area, and the capability of full-range measurement with high precision up to 1 mm.
Description
Technical Field
The present invention relates to a distance measuring apparatus, and more particularly, to an ultrasonic distance measuring instrument without a blind area, which calculates a distance to an object to be measured by measuring a propagation time of ultrasonic waves.
Background
Ultrasonic waves are often used for distance measurement, such as distance meters and level meters, because the ultrasonic waves have strong directivity, do not need to contact an object, are slow in energy consumption and are far away from a medium in propagation. The ultrasonic detection is often relatively rapid and convenient, the calculation is simple, the real-time control is easy to realize, and the requirement of industrial practicality can be met in the aspect of measurement precision, so that the ultrasonic detection method is widely applied to the development of mobile robots.
The ultrasonic range finder transmits ultrasonic waves to a target object through the ultrasonic generator, the ultrasonic waves are reflected back to the ultrasonic range finder when reaching the target object, and the sound wave receiver in the ultrasonic range finder receives the sound waves transmitted by the target object and automatically records the time from the sound wave transmitting moment to the moment when the sound waves are reflected back to the ultrasonic range finder by the target object. Since the speed of transmission of the acoustic wave in the transmission medium is known, the distance from the acoustic wave generator to the target object can be calculated.
As shown in fig. 1, is a general functional block diagram of ultrasonic ranging. The ultrasonic transmitter 1 transmits a beam of ultrasonic waves in a certain direction at a fixed angle alpha and a fixed frequency, timing is started at the same time of transmitting time, the ultrasonic waves propagate in the air and return immediately when encountering an obstacle 3 on the way, and the ultrasonic receiver 2 stops timing immediately when receiving the reflected waves. The propagation speed of the ultrasonic wave in the air is 340m/s, and the distance(s) of the transmitting point from the obstacle can be calculated according to the time t recorded by the timer, namely: and s is 340t/2, and t is the timing time. Of course, the ultrasonic wave may propagate in other propagation media, and assuming that the propagation speed of the ultrasonic wave in the propagation medium is v m/s, the distance s between the emitting point and the obstacle is vt/2.
Therefore, the measuring distance can be obtained by only controlling the transmitting time of the ultrasonic wave and collecting the round-trip time interval from the self-transmission of the ultrasonic wave to the receiving of the transmitted wave from the measured object.
Here, the installation distance between the transmitting head 1 and the receiving head 2 is fixed to x, the distance between x and the measured object 3 forms an acute isosceles triangle, while the coverage area of the transmitted wave is limited, i.e., the angle α of the transmitted wave is limited, so that when the measured object comes close to the sensor, the acute isosceles triangle is transformed to an obtuse isosceles triangle, and due to the limitation of α, when the measured object comes very close to the sensor, the obtuse angle cannot be further increased, thus forming a blind zone, which is basically an inherent characteristic of the ultrasonic rangefinder.
The ultrasonic distance measuring instrument has the advantages of reliable performance, simple structure, low production cost, convenient use, high measuring precision, capability of working in severe environment and the like.
The main application range of ultrasonic ranging is as follows: real-time measurement of the diameter of a winding drum, monitoring of working conditions, size classification or selection of objects, control of bedding planes and liquid levels, proximity early warning or safety precaution, non-contact distance measurement, system output and the like.
At present, two methods are generally adopted for designing an ultrasonic range finder: firstly, the ultrasonic distance measuring instrument is designed by using an application specific integrated circuit, but the cost of the application specific integrated circuit is very high; and the other is designed by using conventional discrete devices and a single chip microcomputer. However, the two methods have the greatest common problem that the measurement blind area is large, and the blind area is usually more than 15cm for short-distance measurement, such as 1m range; the dead zone in the range of 2m reaches more than 20cm, the dead zone above 6m reaches 40cm, and some products even reach 80 cm. When the sensor is used, the large blind area can not realize the short-distance measurement, the short-distance measurement is just like a blind person, and the long-distance measurement can only be seen by far. Under the state of the prior art, the ultrasonic range finder is difficult to simultaneously ensure that the dead zone is reduced and the range is large. In addition, the characteristics of the ultrasonic distance measuring instrument make it have a very large application range, so that an ultrasonic distance measuring instrument which can reduce a blind area and has a large measuring range is needed.
Disclosure of Invention
The technical problem to be solved by the invention is to provide an ultrasonic distance meter without a blind area, which has a large measuring range, a measuring distance of 10m, no measuring blind area, full-range measurement and a measuring precision of 1 millimeter (1mm), aiming at the defects of large measuring blind area, limited measuring range and low precision in the prior art.
The technical scheme adopted by the invention for solving the technical problems is as follows: the ultrasonic range finder without the blind area is constructed and comprises an ultrasonic wave transmitting module for transmitting ultrasonic waves to a measured object, an ultrasonic wave receiving module for receiving echo waves reflected by the measured object, a signal amplifying module which is electrically connected with the ultrasonic wave receiving module and used for amplifying the echo waves, a signal processing module which is connected with the signal amplifying module and used for calculating to obtain a preliminary distance value, and a signal storage and control module which is connected with the signal processing module and used for recording the preliminary distance value and controlling to output a final distance value; and the waveform adjusting module is connected with and controlled by the signal storage and control module and is used for adjusting the shape of the ultrasonic wave transmitted by the ultrasonic wave transmitting module in real time.
The ultrasonic range finder without the blind area further comprises a signal compensation module connected with the signal storage and control module.
In the ultrasonic range finder without the blind area, the flow of processing signals by each module comprises the following steps:
(S301) firstly, carrying out ultrasonic full-power transmission;
(S302) detecting whether a receiving signal exists, if so, turning to the step (S303), otherwise, returning;
(S303) counting and calculating a preliminary distance value between the measured object and the measured object;
(S304) recording the obtained preliminary distance value;
(S305) adjusting a duty cycle of a transmit waveform;
(S306) judging whether the recording times is more than the preset times, if so, turning to the step (S307), otherwise, turning to the step (S302);
(S307) data fusion processing is performed, signal compensation is performed, and the final distance value is output, and the process returns to step (S302).
In the ultrasonic range finder without a blind zone of the present invention, the adjusting the duty ratio of the transmission waveform in (S305) includes: judging whether the distance value obtained in the step (S304) is larger than a first preset value or not, and if so, adjusting the duty ratio of the square wave to be a first duty ratio; otherwise, judging whether the distance value is smaller than a second preset value, if so, adjusting the duty ratio of the square wave to be a second duty ratio, otherwise, adjusting the duty ratio of the square wave to be a third duty ratio.
In the ultrasonic range finder without a blind area of the present invention, the predetermined number of times in the step (S305) is 3, 4 or 5; the first predetermined value is 6 meters and the second predetermined value is 1 meter; the first duty cycle is 75%, the second duty cycle is 25%, and the third duty cycle is 50%.
In the ultrasonic distance meter without the blind area, the data fusion processing in the step (S307) is to simply remove the maximum value and the minimum value from the signals acquired by the predetermined times and to average the remaining values.
In the ultrasonic distance meter without blind area, the signal compensation in the step (S307) is performed by the signal compensation module in three ways: (1) compensating the difference between the moment of receiving the echo and the trigger counting stop after the signal processing is finished; (2) compensating the counting precision of the single chip microcomputer; (3) the influence of the environment on the sound velocity of the ultrasonic wave is compensated.
The invention also provides an ultrasonic distance measurement method, which comprises the following steps: (a) firstly, carrying out ultrasonic full-power transmission; (b) detecting whether a received signal exists, if so, turning to the step (c), otherwise, returning; (c) counting and calculating a preliminary distance value between the measured object and the measured object; (d) recording the obtained preliminary distance value; (e) adjusting a duty cycle of a transmit waveform; (f) judging whether the recording times are more than the preset times, if so, turning to the step (g), otherwise, turning to the step (b); (g) and (c) carrying out data fusion processing, compensating signals, outputting final distance values, and returning to the step (b).
In the ultrasonic ranging method of the present invention, the adjusting the duty cycle of the transmit waveform in (e) comprises: judging whether the distance value obtained in the step (d) is larger than a first preset value or not, and if so, adjusting the duty ratio of the square wave to be a first duty ratio; otherwise, judging whether the distance value is smaller than a second preset value, if so, adjusting the duty ratio of the square wave to be a second duty ratio, otherwise, adjusting the duty ratio of the square wave to be a third duty ratio.
In the ultrasonic ranging method of the present invention, the data fusion processing in step (g) is to simply remove the maximum value and the minimum value from the signals acquired for a predetermined number of times, and average the remaining values.
The ultrasonic range finder without the blind area has the following beneficial effects: the range finding blind area is eliminated, and full-range measurement can be achieved; the measuring range is large, and the measuring distance can reach 10 meters. In addition, the signal compensation module can improve the measurement accuracy, and the measurement accuracy is as high as 1 millimeter.
Drawings
The invention will be further described with reference to the accompanying drawings and examples, in which:
FIG. 1 is a schematic block diagram of ultrasonic ranging in the prior art;
FIG. 2 is a logic block diagram of a preferred embodiment of the blind-zone-free ultrasonic rangefinder of the present invention;
FIG. 3 is a signal processing flow diagram of a preferred embodiment of the blind-zone-free ultrasonic rangefinder of the present invention;
FIG. 4 is a schematic block diagram of the preferred embodiment of the non-blind zone ultrasonic rangefinder of the present invention;
FIG. 5 is a flow chart of adjusting the duty cycle of the transmitted waveform in a preferred embodiment of the non-blind zone ultrasonic range finder of the present invention;
FIG. 6 is a schematic circuit diagram of a preferred embodiment of the non-blind zone ultrasonic rangefinder of the present invention.
Detailed Description
FIG. 2 is a logic block diagram of a preferred embodiment of the non-blind zone ultrasonic rangefinder of the present invention. The ultrasonic wave signal amplification module, signal processing module, signal storage and control module, waveform adjustment module and signal compensation module. The ultrasonic wave transmitting module transmits ultrasonic waves to the obstacle. The ultrasonic wave is transmitted back after reaching the barrier, and the ultrasonic wave receiving module receives the transmitted ultrasonic wave and transmits the transmitted ultrasonic wave to the signal amplifying module. The signal is amplified and then transmitted to the signal processing module, and the signal processing module counts and calculates a preliminary distance value. This preliminary distance value is then transmitted to a signal storage and control module, which stores and records the number of measurements. And meanwhile, the waveform adjusting module can be controlled to adjust the duty ratio of the transmitted waveform according to the initial distance value. The waveform adjusting module adjusts the duty ratio of the transmitted waveform according to the recorded distance value, so that the transmitting power is adjusted, and the amplification factor is adjusted in a phase-changing manner. After the signal acquisition of predetermined number of times, signal storage and control module can fuse all preliminary distance values of record and handle in order to guarantee to eliminate the error signal, send the distance value after handling to signal compensation module at last and carry out signal compensation to output has the final distance value of certain measurement accuracy.
FIG. 3 is a flow chart of signal processing in a preferred embodiment of the blind-zone-free ultrasonic range finder of the present invention. In step 301, the ultrasound transmission module first performs full power transmission. Next, in step 302, the ultrasonic receiving module detects whether there is a received signal, if yes, go to step 303, otherwise return to. In step 303, the signal is amplified by the signal amplification module and counted by the signal processing module and a preliminary distance value is calculated. In step 304, the signal storage and control module records the preliminary distance value obtained in step 303. In step 305, the waveform adjustment module adjusts the duty cycle of the transmitted waveform according to the preliminary distance value, so as to adjust the transmitted power, and further, the phase-variable adjustment amplification factor. In step 306, the signal storage and control module determines whether the recorded number of times is greater than a predetermined number of times, if so, it indicates that the distance value required for recording has been recorded, and the process goes to step 307, where the data is fused, and the signal compensation module compensates the distance value and outputs the final result. If the predetermined number of times has not been reached, then proceed to step 302. After the final distance value is output in step 307, the process returns to step 302, and the next final distance value is calculated, recorded, and output.
The modules of the ultrasonic range finder without blind area according to the present invention will be further described with reference to the preferred embodiment of the present invention.
1. Ultrasonic transmitting module
The preferred embodiment of the present invention employs a transmission enhanced 40k frequency square wave excitation ultrasonic transmitter. The single-chip microcomputer software generates 40k square waves, and the transmitter hardware adopts two-way signals, namely square wave signals are provided at two ends of the ultrasonic transmitting head. Typically a single signal is used. Therefore, the strength of the transmitted signal can be enhanced according to the situation, and the frequency of the signal is not changed, so that the strength of the transmitted signal can be adjusted.
The problem of the ultrasonic sensor that the measurement blind area is larger in the case of a larger detection distance is because the transmission power must be increased if the detection distance is to be increased. The larger the transmitting power of the transmitter is, the more easily the receiver receives the error signal when detecting the object in the close range. The missignal is a signal reflected by a measured object, which is not detected by ultrasonic waves, but a transmitted waveform directly interferes with a receiver, namely a cross-talk signal. Therefore, if a long detection distance and a small blind area, even a blind area, are to be realized, it is necessary to change the transmission mode, that is, to adopt the acoustic waveform segmentation adjustment technique.
In the preferred embodiment of the present invention, the signal is transmitted in a segmented manner instead of a conventional fixed signal strength manner. When detecting long-distance objects, the transmitting module transmits at full power; when detecting an object with a distance between the middle section and the object, enabling the transmitting module to transmit by adopting half power; when detecting a short-distance object, the transmitting module is made to adopt low power. Therefore, the problem of a large blind area caused by interference caused by the super-strong signal can be solved.
However, to solve the blind area inherent to the ultrasonic sensor itself, the waveform of the signal must be changed. As can be seen from fig. 1, the blind area is formed because the angle α is fixed, and when the distance between the object to be measured and the ultrasonic sensor is very close, the triangle formed by the detected waveform cannot be deformed any more, i.e. the obtuse angle of the isosceles triangle cannot be enlarged any more, so that the blind area is formed. In the preferred embodiment of the present invention, as shown in fig. 4, when the distance between the object to be measured 3 and the ultrasonic sensor is gradually decreased, the shape of the ultrasonic wave can be adjusted in real time, that is, the angle α of the emission waveform of the ultrasonic wave is gradually increased, so as to eliminate the blind area triangle.
2. Ultrasonic receiving module
The ultrasonic receiving module is matched with the ultrasonic transmitting module and is used for receiving ultrasonic waves reflected by the object to be measured. In the preferred embodiment of the present invention, the ultrasonic receiving module is the same as the prior art and will not be described in detail herein.
3. Signal amplification module
The received ultrasonic wave modulated pulses are converted into alternating voltage signals, the signal amplitude of which varies with distance. In the case of a long distance, the echo of the acoustic wave is weak, and thus the amplitude of the signal converted into an electric signal is small, and amplification processing is required. Signals are usually amplified by 2-3 stages, and the amplification factor is about hundreds of thousands of times. If the signal is weak (long distance) and amplified according to the conventional mode, the signal is enhanced; when the signal is strong (at a close distance), the signal is amplified to be too strong to be saturated, which further causes a blind area to be formed. Thus, there is a contradiction, and it is necessary to ensure that both weak and small signals are amplified sufficiently and strong signals are not distorted during signal amplification and processing. In the preferred embodiment of the invention, the control of signal processing is realized by combining hardware and software, and the amplification degree can be intelligently adjusted to balance the amplification degree. The specific adjustment method will be described in the following waveform adjustment block.
4. Signal processing module
After the signals are amplified, in signal processing, the propagation time of the ultrasonic waves is obtained by counting the time difference from the transmission of the ultrasonic waves to the reception of the echo waves, and then the preliminary distance value of the measured object can be calculated.
5. Signal storage and control module
The signal storage and control module can record the initial distance value obtained by the signal processing module and control the waveform adjusting module to carry out waveform adjustment according to the size of the distance value. And meanwhile, calculating the recording times, judging whether the recording times reach the preset times, and if so, performing fusion processing on all the preliminary distance values within the preset times to eliminate error signals. Meanwhile, the data after fusion processing can be transmitted to the signal compensation module, the signal compensation module is controlled to perform compensation processing on the data, and a final distance value with enough precision is obtained.
In a preferred embodiment of the invention, the signal is acquired 5 times, simply removing the maxima and minima, leaving the values to be averaged. The reason why 5 times of collection are performed is that if the number of times is too large, the measurement time is too long, which results in slow reaction and non-compliance with the real-time requirement. Of course, it will be understood by those skilled in the art that the number of signal acquisitions may also be adjusted as desired. However, if the number of signal acquisition times is too large, the calculation time is easily too long, and the response is slow; and if the number of signal acquisition times is too small, the fusion value is not achieved. The number of signal acquisitions is preferably selected to be 3-5.
6. Waveform adjusting module
As shown in fig. 5, a flow chart for adjusting the shape of the ultrasonic wave in real time according to the change of the detection distance is given. Firstly, the 40k square wave is realized by high and low levels, and the square wave is output to a relevant pin of a singlechip, so that the emission of ultrasonic waves is realized. Then, it is determined whether the distance between the object to be measured and the ultrasonic sensor is greater than a first predetermined value, in the preferred embodiment, the first predetermined value is 6 meters, and if so, the duty ratio of the square wave is adjusted to a first duty ratio, in the preferred embodiment, the first duty ratio is selected to be 75%. If the distance between the measured object and the ultrasonic sensor is smaller than the first predetermined value, it is determined again whether the distance between the measured object and the ultrasonic sensor is smaller than a second predetermined value, in the preferred embodiment, the second predetermined value is 1 meter, and if the distance between the measured object and the ultrasonic sensor is smaller than the second predetermined value, the duty ratio of the square wave is adjusted to be a second duty ratio, in the preferred embodiment, the second duty ratio is selected to be 25%. If the distance is greater than the second predetermined value and less than the first predetermined value, in the preferred embodiment, i.e. the distance value is between 1 and 6 meters, the duty cycle of the square wave is adjusted to a third duty cycle, which in the preferred embodiment is chosen to be 50%. In the preferred embodiment of the invention, the square wave duty cycles used are 25%, 50% and 75%, respectively. Those skilled in the art will appreciate that other ranges of values of square wave duty cycle may be employed.
In the waveform adjusting module, the transmitting power can be adjusted by adjusting the duty ratio of the transmitting waveform. The transmitting power of the ultrasonic transmitting module is adjusted, which is equivalent to adjusting the amplification factor in the signal amplifying and processing module, so that different amplification factors are adopted for signals with different strengths according to the distance, thereby ensuring that weak signals are amplified sufficiently and strong signals are not distorted.
7. Signal compensation module
In order to ensure the measurement accuracy, three aspects of compensation exist in the signal acquisition process, namely, a difference exists between the moment when the echo is received and the triggering of counting stop after the signal processing is finished, and compensation is needed; secondly, the single chip microcomputer compensates the counting precision; and thirdly, the influence of the environment such as temperature on the sound velocity of the ultrasonic wave is compensated.
(1) The error formed in the first case is relatively random, since the received first echo is not necessarily formed by the reflection of the first wave transmitted before, and may be reflected back by one of the transmitted series of waves, i.e. lost, therefore, 5 acquisitions are performed in the previous data acquisition, and the error is compensated, and the systematic error compensation is performed through the following (4) th strip.
(2) And the second condition can adopt a singlechip with high main frequency, and the minimum instruction period is selected as the step value of counting during counting, so that the counting interval can be accurately collected, the counting precision is improved, and the measurement precision is directly improved.
(3) And the temperature compensation of the third case, because the transmission speed of the sound wave is influenced by the temperature and the medium,
C＝331.5+0.607t(m/s)
in the above formula, C is the sound velocity, where C is 340m/s is the velocity at 15 ° at normal temperature, and t is the temperature, and as can be seen from the above formula, the velocity is greatly affected by the temperature, and if temperature compensation is not performed, the measurement accuracy of the sensor is affected.
Temperature compensation requires the use of a temperature sensor in the system to detect the ambient temperature in real time and calculate the value of the speed of sound C, thereby obtaining the distance value at this speed.
(4) And (5) calibrating the sensor. The sensor carries out a series of distance measurement, obtains the difference between the measured value and the true value, obtains the system error, and carries out proportion compensation.
FIG. 6 is a schematic circuit diagram of a preferred embodiment of the non-blind zone ultrasonic rangefinder of the present invention. In fig. 6, the ultrasonic wave emission is shown on the left, and IOA0 and IOA1 are output ports of the single chip microcomputer, and are used for applying excitation signals to the ultrasonic wave emission device, and signal conditioning is performed through the two ports; the right side is an ultrasonic signal receiving and amplifying processing module, the IOA3 is an input signal of the single chip microcomputer, the single chip microcomputer is omitted in the figure, and the single chip microcomputer processes the input signal of the IOA3 to obtain a distance value.
The invention also provides an ultrasonic distance measurement method. Firstly, ultrasonic full power transmission is carried out, then whether a received signal exists is detected, if not, the detection is returned to continue, and if so, counting is carried out and a preliminary distance value between the ultrasonic full power transmission and the object to be detected is calculated. And then recording the obtained preliminary distance value and adjusting the duty ratio of the transmitted waveform in real time according to the preliminary distance value, if the preliminary distance value is greater than a first preset value, adjusting the duty ratio of the square wave to be a first duty ratio, if the preliminary distance value is less than a second preset value, adjusting the duty ratio of the square wave to be a second duty ratio, and if the preliminary distance value is between the first preset value and the second preset value, adjusting the duty ratio of the square wave to be a third duty ratio. And then judging whether the recording times are more than the preset times, if not, continuously detecting whether a received signal exists, if so, performing fusion processing, compensating the signal and outputting a final distance value. The data fusion process described herein is a process of simply removing the maximum and minimum values from the signals acquired a predetermined number of times and averaging the remaining values.
In a preferred embodiment of the invention, said predetermined number of times is 3, 4 or 5. If the number of signal acquisition times is too large, the calculation time is easily too long, and the response is slow; and if the number of signal acquisition times is too small, the fusion value is not achieved. The number of signal acquisitions is preferably selected to be 3-5. The first predetermined value is 6 meters and the second predetermined value is 1 meter. The first duty cycle is 75%, the second duty cycle is 25%, and the third duty cycle is 50%. These values are selected for use in the preferred embodiment and it will be apparent to those skilled in the art that other values may be used without departing from the spirit and scope of the invention.
The ultrasonic range finder without the blind area eliminates the range finding blind area and can achieve full-range measurement; the measuring range is large, and the measuring distance can reach 10 meters. In addition, the signal compensation module can improve the measurement accuracy of the ultrasonic distance measuring instrument, and the measurement accuracy is up to 1 millimeter.
Claims (5)
1. An ultrasonic distance meter without blind area comprises an ultrasonic wave transmitting module for transmitting ultrasonic waves to a measured object, an ultrasonic wave receiving module for receiving echo waves reflected by the measured object, a signal amplifying module which is electrically connected with the ultrasonic wave receiving module and amplifies the echo waves, a signal processing module which is connected with the signal amplifying module and calculates to obtain a preliminary distance value, and a signal storage and control module which is connected with the signal processing module and is used for recording the preliminary distance value and controlling to output a final distance value,
further comprising:
the waveform adjusting module is connected with and controlled by the signal storage and control module and is used for adjusting the duty ratio of the ultrasonic wave transmitted by the ultrasonic wave transmitting module;
the signal compensation module is connected with the signal storage and control module; and is
The process of processing signals by each module of the non-blind area ultrasonic range finder comprises the following steps:
(S301) the ultrasonic wave transmitting module firstly transmits the ultrasonic wave with full power;
(S302) the ultrasonic receiving module detects whether a receiving signal exists, if so, the step is carried out (S303), otherwise, the step is returned;
(S303) amplifying the signal by a signal amplifying module, counting by a signal processing module and calculating a preliminary distance value;
(S304) the signal storage and control module records the preliminary distance value obtained in step (S303);
(S305) the waveform adjusting module adjusts a duty ratio of the transmission waveform according to the preliminary distance value, thereby adjusting transmission power;
(S306) the signal storage and control module judges whether the recording times are more than the preset times, if so, the step is carried out (S307), otherwise, the step is carried out (S302);
(S307) carrying out data fusion processing, carrying out signal compensation by a signal compensation module, outputting a final distance value, and returning to the step (S302); wherein,
the adjusting the duty cycle of the transmit waveform in the step (S305) includes: judging whether the distance value obtained in the step (S304) is larger than a first preset value or not, and if so, adjusting the duty ratio of the square wave to be a first duty ratio; otherwise, judging whether the distance value is smaller than a second preset value, if so, adjusting the duty ratio of the square wave to be a second duty ratio, otherwise, adjusting the duty ratio of the square wave to be a third duty ratio;
the first predetermined value is 6 meters and the second predetermined value is 1 meter; the first duty cycle is 75%, the second duty cycle is 25%, and the third duty cycle is 50%.
2. The non-blind area ultrasonic range finder of claim 1,
the predetermined number of times in the step (S305) is 3, 4, or 5.
3. The ultrasonic range finder without blind spot according to claim 1, wherein the data fusion process in step (S307) is to simply remove the maximum value and the minimum value of the signals acquired through the predetermined number of times and average the remaining values.
4. An ultrasonic distance measuring method is characterized by comprising the following steps:
(a) firstly, carrying out ultrasonic full-power transmission;
(b) detecting whether a received signal exists, if so, turning to the step (c), otherwise, returning;
(c) counting and calculating a preliminary distance value between the measured object and the measured object;
(d) recording the obtained preliminary distance value;
(e) adjusting the duty ratio of a transmitting waveform according to the preliminary distance value to adjust transmitting power;
(f) judging whether the recording times are more than the preset times, if so, turning to the step (g), otherwise, turning to the step (b);
(g) performing data fusion processing, performing signal compensation, outputting a final distance value, and returning to the step (b); wherein,
the adjusting the duty cycle of the transmit waveform in step (e) comprises: judging whether the distance value obtained in the step (d) is larger than a first preset value or not, and if so, adjusting the duty ratio of the square wave to be a first duty ratio; otherwise, judging whether the distance value is smaller than a second preset value, if so, adjusting the duty ratio of the square wave to be a second duty ratio, otherwise, adjusting the duty ratio of the square wave to be a third duty ratio;
the first predetermined value is 6 meters and the second predetermined value is 1 meter; the first duty cycle is 75%, the second duty cycle is 25%, and the third duty cycle is 50%.
5. The ultrasonic ranging method according to claim 4, wherein the data fusion process in the step (g) is to simply remove the maximum value and the minimum value of the signals acquired after a predetermined number of times and average the remaining values.
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| CN2006100633989A CN101173986B (en) | 2006-10-30 | 2006-10-30 | Ultrasonic distance measuring apparatus without blind zone |
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| CN2006100633989A CN101173986B (en) | 2006-10-30 | 2006-10-30 | Ultrasonic distance measuring apparatus without blind zone |
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| CN2006100633989A Expired - Fee Related CN101173986B (en) | 2006-10-30 | 2006-10-30 | Ultrasonic distance measuring apparatus without blind zone |
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| CN109493633A (en) * | 2018-12-20 | 2019-03-19 | 广州小鹏汽车科技有限公司 | It is a kind of can parking stall detection method and device |
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| CN111679281B (en) * | 2020-05-27 | 2023-06-16 | 南京汽车集团有限公司 | Method for improving detection performance of ultrasonic sensor |
| CN112162289B (en) * | 2020-08-28 | 2023-11-17 | 国创移动能源创新中心(江苏)有限公司 | Ultrasonic ranging method and device |
| CN112630781A (en) * | 2020-11-27 | 2021-04-09 | 深圳数联天下智能科技有限公司 | Ultrasonic distance measuring device and ultrasonic distance measuring method |
| CN114035246B (en) * | 2021-03-26 | 2024-02-27 | 山东省气象局大气探测技术保障中心(山东省气象计量站) | Meteorological verification switching module, annular conveying device and application method of meteorological verification switching module |
| CN113932881B (en) * | 2021-10-15 | 2023-11-10 | 常州市成丰流量仪表有限公司 | Method for measuring and calculating dead zone-free magnetostrictive material level sensor |
| CN114322867B (en) * | 2021-11-22 | 2024-03-22 | 天津大学 | Coaxial double-rotor-wing tip distance measurement system and method based on ultrasonic measurement |
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| US3586936A (en) * | 1969-10-16 | 1971-06-22 | C & B Corp | Visual tuning electronic drive circuitry for ultrasonic dental tools |
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| US3586936A (en) * | 1969-10-16 | 1971-06-22 | C & B Corp | Visual tuning electronic drive circuitry for ultrasonic dental tools |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN109493633A (en) * | 2018-12-20 | 2019-03-19 | 广州小鹏汽车科技有限公司 | It is a kind of can parking stall detection method and device |
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