JPWO2008023714A1 - Measuring method and measuring program - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method capable of measuring the distance of a target object to the target object and the surface shape of the target object using ultrasonic waves, and particularly capable of measuring even when the target object is located obliquely. SOLUTION: A step S1 for continuously outputting ultrasonic waves of a first frequency, a step S2 for sampling reflected waves from a target object related to the ultrasonic waves of the first frequency, and a sampled first sampling Step S3 for calculating the relative speed of the target object based on the data string, Step S4 for outputting the ultrasonic wave of the second frequency in a pulse shape, and the target object relating to the ultrasonic waves of the first and second frequencies. Step S5 of sampling the reflected wave, and detecting one or a plurality of reflection times related to the ultrasonic wave of the second frequency based on the sampled second sampling data string, and up to the target object based on the reflection time Or step S6 for calculating the number and depth of steps on the surface of the target object. Since this method can detect the distance and level difference to the wall, it can be used for garage of a car. [Selection] Figure 6

Description

  The present invention relates to a measurement method and a measurement program for measuring the speed of an object, the distance to the object, and the like, and can be applied particularly when the target object is directed obliquely. Measurement method and measurement program for measuring distance to target object by calculating frequency spectrum of reflected wave from target object related to ultrasonic wave having single frequency or two different kinds of frequencies transmitted separately, and measurement program And a measuring device. Moreover, this measurement method etc. can be used for parking assistance of a motor vehicle.

  As a method of measuring the distance to an object using ultrasonic waves, a method in which the distance is measured by measuring the time from ultrasonic wave emission to reflected wave acquisition and multiplying it by the speed of sound is generally used. Met. On the other hand, a method for measuring not only the distance but also the moving speed of the object and a method with high measurement accuracy have been proposed. For example, as described in Patent Document 1, a speed measuring device that measures the speed of a target object such as a toy and an entertainment device using ultrasonic waves has been developed. In this velocity measuring device, an ultrasonic signal is transmitted toward a target object by converting an electrical signal having an ultrasonic frequency of 40 kHz using a piezoelectric element of a transmitter. The ultrasonic wave reflected from the target object is converted into an electric signal by the piezoelectric element of the receiver. When an electric signal having an ultrasonic frequency of 40 kHz generated on the transmitter side and an electric signal converted on the receiver side are input to the mixer, an electric signal having a difference frequency (beat frequency) between the two signals is input. A signal can be obtained. This frequency difference value uniquely corresponds to the relative velocity of the target object. Therefore, it is possible to calculate the speed of the target object by specifying the frequency of the electric signal of the beat frequency using an edge detector, a timing circuit, or the like.

  Patent Document 2 discloses a measurement method that uses electromagnetic waves to measure the speed of a target object such as an automobile and the distance to the target object. In this method, the frequency of the electromagnetic wave radiated from the antenna is increased and decreased at a constant rate. An intermediate frequency signal is generated by mixing the reception signal related to the electromagnetic wave reflected by the target object and received by the antenna and the transmission signal related to the transmitted electromagnetic wave. Specify the frequency of the intermediate frequency signal when the frequency of the radiated electromagnetic wave increases and the frequency of the intermediate frequency signal when the frequency of the radiated electromagnetic wave decreases, and solve the simultaneous linear equations using these as coefficients. Thus, the speed of the target object and the distance to the target object can be calculated.

  Patent Document 3 discloses a method for extracting a first reflected pulse from noise for the purpose of highly accurate distance measurement, calculating a distance, and calculating a sound speed from an arrival time to a sensor at a known distance. ing. In this method, 8 pulses of ultrasonic waves of a specific frequency are radiated, the received wave is greatly amplified for each noise, passed through a filter, correlated with the sine wave equivalent to the emitted ultrasonic wave, and the extracted waveform is zero-crossed. The point period is calculated, and the point where the specific period lasts for 8 pulses is regarded as the time when the reflected wave arrives.

JP 2005-54063 A Japanese Patent No. 3457722 International Publication WO2005 / 010552 Pamphlet JP 2007-98967 A Japanese Patent Laying-Open No. 2005-201637 JP-A-8-324366

In the invention described in Patent Document 1, there is a problem that only the velocity of the target object can be measured using ultrasonic waves. In the invention described in Patent Document 3, it is possible to measure with high accuracy, but there is a problem that the object to be measured is only the distance to the object.
Further, in the conventional measurement method, when the target object 24 is positioned perpendicular to the radiation direction from the ultrasonic transmission unit 22 in the measurement apparatus 21 as shown in FIG. The distance to the target object and the speed of the target object can be measured by receiving the reflected wave at the ultrasonic receiver 23 located adjacent to the unit 22. However, when the target object is located obliquely as shown in (b), there is a problem that the intensity of the reflected wave received by the ultrasonic wave receiving unit 23 is weak and the distance measurement cannot be performed.

ただし、Ｒ_（θ）は指向性関数であり、数式２で与えられる。

ここで、Ｐ_０は放射音圧、Ｚは測定装置−物体間距離、θは測定装置と物体とのなす角度、ａは発振器の開口半径、ｋは放射する超音波の波数である。Explain that it is difficult to measure an object located obliquely. As shown in FIG. 2, in the measurement of the target object 24 positioned obliquely by the measurement device 21 including the transmission unit 22 and the reception unit 23, the reflected wave by the ultrasonic object radiated from the actual transmission unit 22 is It can be regarded as an ultrasonic wave radiated from the mirror image transmission unit 32.
The sound pressure when the ultrasonic wave radiated from the mirror image transmission unit 32 reaches the real image reception unit 23, that is, the reception sound pressure P of the reflected wave, is given by Equation 1.

However, R _(θ) is a directivity function and is given by Equation 2.

Here, P ₀ is the radiation sound pressure, Z is the distance between the measuring device and the object, θ is the angle between the measuring device and the object, a is the opening radius of the oscillator, and k is the wave number of the emitted ultrasonic wave.

In Equation 1, when the wavelength λ = 0.85 cm (wavelength in air with respect to an ultrasonic wave having a frequency of 40 kHz) and a = 1 cm, the directivity function R _(θ) is 0 in the range of 0 ° ≦ θ ≦ 90 °. Is calculated, θ = 32 °. That is, when an ultrasonic wave having a frequency of 40 kHz is radiated, the reflected wave reaches the sensor theoretically if the angle with the object is 32 ° or less. However, in practice, the attenuation is large due to the deviation from the center of the directivity, the arrival distance, and the like, making measurement difficult.

  The present invention has been made in order to solve the above-described problems, and provides a measurement method, a measurement program, and a measurement apparatus that can measure the distance to a target object using a relatively simple technical configuration. The purpose is to provide. It is another object of the present invention to provide a measurement method, a program, and an apparatus that can measure the distance to the target object and the speed of the target object. It is another object of the present invention to provide a measurement method, a measurement program, and a measurement apparatus that can detect the surface shape of a target object. Furthermore, an object of the present invention is to provide a measurement method, a program, and a measurement apparatus that detect the distance of a target object even when the target object is located obliquely. It is another object of the present invention to provide a measurement method, a program, and a measurement apparatus that detect the distance and surface shape of the target object even when the target object is located obliquely. It is another object of the present invention to provide a car garage storage method using the measurement method and program. It is another object of the present invention to attach the measuring device to an automobile so that it can be used for supporting garage entry of the automobile.

In order to solve the above technical problem, a measurement method or a measurement program according to the present invention includes a step (step) of continuously outputting ultrasonic waves of a first frequency over a predetermined period, A step (step) of sampling a reflected wave from the target object related to the ultrasonic wave, a step (step) of calculating a relative velocity of the target object based on the sampled first sampling data sequence, and a step over a predetermined period. A step (step) of outputting ultrasonic waves of the second frequency in a pulsed manner after continuously outputting ultrasonic waves of the first frequency, and relating to the ultrasonic waves of the first frequency and the ultrasonic waves of the second frequency Whether the reflected wave from the target object is sampled (step) and whether the second frequency ultrasonic wave is transmitted based on the sampled second sampling data string A step (step) of detecting one or a plurality of reflection times until the target object is reflected and received, and a distance to the target object or a surface of the target object based on the detected one or more reflection times And a step of calculating the number and depth of the upper steps.
Accordingly, it is possible to measure the relative speed of the target object, the distance to the target object, and even the surface shape of the target object using a relatively simple technical configuration. In particular, it is possible to accurately measure the distance to the target object positioned obliquely with respect to the measuring device.
In addition, each said process (step) does not necessarily need to be performed in the order described. The process (step) described before may be executed later than the process (step) described later, and the process (step) described before and the process (step) described later are performed. You may make it perform in parallel. For example, the step of calculating the relative velocity of the target object based on the first sampling data string may be executed after the step of outputting the ultrasonic wave of the second frequency in a pulse shape, and these steps are performed in parallel. May be executed automatically.

The measurement method or the measurement program according to the present invention includes a step (step) of continuously outputting ultrasonic waves of the first frequency over a predetermined period, and continuously outputting ultrasonic waves of the first frequency over a predetermined period. And outputting the ultrasonic wave of the second frequency in the form of pulses, and sampling the reflected wave from the target object related to the ultrasonic wave of the first frequency and the ultrasonic wave of the second frequency. A step (step), a step (step) of calculating the relative velocity of the target object based on the sampled sampling data sequence, and an ultrasonic wave having the second frequency transmitted based on the sampled sampling data sequence A step (step) of detecting one or a plurality of reflection times until the object is reflected and received, and based on the detected one or more reflection times. There are, in which as a step (step) for calculating the number and depth of the step on the surface of the distance or the object, to the object.
Accordingly, it is possible to measure the relative speed of the target object, the distance to the target object, and even the surface shape of the target object using a relatively simple technical configuration. In particular, it is possible to accurately measure the distance to the target object positioned obliquely with respect to the measuring device. In addition, the sampling data is stored because it is sufficient to perform sampling once to calculate the distance to the target object as well as the relative speed of the target object and the number and depth of steps on the surface of the target object. It is possible to simplify sampling data storage processing, transfer processing, and the like in the storage means, and the system configuration of the measuring apparatus can be simplified.
In addition, each said process (step) does not necessarily need to be performed in the order described. The process (step) described before may be executed later than the process (step) described later, and the process (step) described before and the process (step) described later are performed. You may make it perform in parallel. For example, the step of calculating the relative velocity of the target object based on the sampling data sequence may be performed after the step of detecting one or a plurality of reflection times based on the sampling data sequence, and these steps may be performed in parallel. You may make it perform to.

Moreover, the measuring method according to the present invention outputs ultrasonic waves of the second frequency for approximately one wavelength.
Accordingly, if the reflection times of the plurality of reflected waves reflected from the surface portions having different heights on the surface of the target object are shifted by a time corresponding to approximately one wavelength of the ultrasonic wave, the ultrasonic wave receiving unit A plurality of reflected waves can be received separately without being superimposed, and the resolution related to the calculation of the difference in height (depth of the step) between different surface portions can be improved.

In addition, the measurement method according to the present invention includes a sampling data sequence sampled to detect one or a plurality of reflection times from when the ultrasonic wave of the second frequency is transmitted until it is reflected by the target object and received. Are divided into minute sections, and the length of each minute section is made equal to approximately one wavelength of ultrasonic waves of the second frequency.
Thereby, since the minimum time width capable of detecting the frequency spectrum related to the ultrasonic wave of the second frequency is set as the minute section, a plurality of pieces reflected from the surface portions having different heights on the surface of the target object It is possible to reduce the lower limit value of the depth of the step that makes it possible to receive the reflected wave in different micro intervals, and it is possible to improve the resolution related to the calculation of the depth of the step.

In the measurement method according to the present invention, the relative speed of the target object is used to correct the distance to the target object or the depth of the step on the surface of the target object.
Thereby, the distance to the target object or the depth of the step on the surface of the target object can be calculated with higher accuracy.

Further, the measurement method according to the present invention applies a fast Fourier transform to a sampling data sequence obtained by arranging a plurality of zeros after a sampling data sequence sampled in order to calculate the relative velocity of the target object. Thus, the frequency spectrum of the reflected wave from the target object related to the ultrasonic wave of the first frequency is calculated.
As a result, the frequency resolution of the frequency spectrum calculated for the reflected wave related to the ultrasonic wave of the first frequency is increased, and the peak frequency related to the reflected wave can be detected more accurately. The speed resolution relating to the calculation of the relative speed can be improved.

Further, the measurement method according to the present invention, after applying a window function to the sampling data sequence obtained by arranging a plurality of zeros after the sampled data sequence sampled to calculate the relative velocity of the target object, Fast Fourier transform is applied.
As a result, it is possible to reduce the error of the frequency spectrum calculated for the reflected wave related to the ultrasonic wave of the first frequency and to detect the peak frequency related to the reflected wave more accurately. An error related to the calculation of the relative speed can be reduced.

In addition, the measurement method according to the present invention includes a sampling data sequence sampled to detect one or a plurality of reflection times from when the ultrasonic wave of the second frequency is transmitted until it is reflected by the target object and received. A high-speed sampling data string obtained by dividing a section made up of the entire sampling data contained in the sub-section into minute sections and repeatedly arranging the sampling data strings made up of the sampling data existing in each minute section. By applying the Fourier transform, the frequency spectrum of the reflected wave received in the minute section is calculated.
As a result, the frequency resolution of the frequency spectrum calculated for the reflected wave from the target object is enhanced, and it becomes possible to detect a minute section in which the reflected wave related to the ultrasonic wave of the second frequency is received with higher accuracy. Therefore, it is possible to reduce an error related to the calculation of the distance to the target object.

In the measurement method according to the present invention, a fast Fourier transform is applied after a window function is applied to a sampling data sequence obtained by repeatedly arranging sampling data sequences consisting of sampling data existing in a minute interval. Is.
As a result, it is possible to reduce the error of the frequency spectrum calculated for the reflected wave from the target object, and to detect the minute section in which the reflected wave related to the ultrasonic wave of the second frequency is received with higher accuracy. Therefore, it is possible to further reduce the error related to the calculation of the distance to the target object.

Further, the measurement method according to the present invention includes a step of continuously outputting an electromagnetic wave having a first frequency over a predetermined period, a step of sampling a reflected wave from a target object relating to the electromagnetic wave having the first frequency, and a sampling Calculating the relative velocity of the target object based on the first sampled data sequence, and continuously outputting the electromagnetic wave of the first frequency over a predetermined period, and then pulsing the electromagnetic wave of the second frequency A step of outputting, a step of sampling a reflected wave from the target object related to the electromagnetic wave of the first frequency and the electromagnetic wave of the second frequency, and an electromagnetic wave of the second frequency based on the sampled second sampling data string Detecting one or a plurality of reflection times from when a signal is transmitted to when it is reflected by the target object and received, and the one or more reflection times detected Based on, in which as a step of calculating the number and depth of the step on the surface of the distance or the object, to the object.
Accordingly, it is possible to measure the relative speed of the target object, the distance to the target object, and even the surface shape of the target object using a relatively simple technical configuration.
Note that the above steps do not necessarily have to be performed in the order described. The process described before may be executed after the process described later, and the process described before and the process described later may be executed in parallel.

The measurement method according to the present invention includes a step of continuously outputting an electromagnetic wave having a first frequency over a predetermined period, and a second method after continuously outputting the electromagnetic wave having a first frequency over a predetermined period. A step of outputting a frequency electromagnetic wave in a pulse shape, a step of sampling a reflected wave from the target object related to the electromagnetic wave of the first frequency and the electromagnetic wave of the second frequency, and the target object based on the sampled sampling data string And calculating one or a plurality of reflection times from when the electromagnetic wave of the second frequency is transmitted to the target object after being reflected based on the sampled sampling data string. And the distance to the target object or the number and depth of steps on the surface of the target object based on one or more detected reflection times It is obtained so as to have a that step.
Accordingly, it is possible to measure the relative speed of the target object, the distance to the target object, and even the surface shape of the target object using a relatively simple technical configuration. In addition, the sampling data is stored because it is sufficient to perform sampling once to calculate the distance to the target object as well as the relative speed of the target object and the number and depth of steps on the surface of the target object. It is possible to simplify sampling data storage processing, transfer processing, and the like in the storage means, and the system configuration of the measuring apparatus can be simplified.
Note that the above steps do not necessarily have to be performed in the order described. The process described before may be executed after the process described later, and the process described before and the process described later may be executed in parallel.

Further, the measurement method or the measurement program according to the present invention includes a step of outputting ultrasonic waves of a predetermined frequency in a pulse shape, a step of sampling reflected waves from a target object related to the ultrasonic waves of the predetermined frequency, and sampling. Based on the sampled data sequence, the reflection time from when the ultrasonic wave of the predetermined frequency is transmitted until it is reflected by the target object and received is detected, and based on the detected reflection time, the target object is detected. And a step of calculating a distance.
This makes it possible to measure the distance of the target object to the target object using a relatively simple technical configuration. In particular, it is possible to accurately measure the distance to the target object positioned obliquely with respect to the measuring device.

The measuring method according to the present invention outputs the ultrasonic wave having the predetermined frequency for approximately one wavelength.
As a result, if the reflection time of the reflected wave reflected on the surface of the target object is shifted by a time corresponding to approximately one wavelength of the ultrasonic wave, the spectral intensity in the frequency band of the emitted ultrasonic wave is reduced in the ultrasonic wave receiving unit. Since the time resolution when searching can be improved, the resolution can be improved when calculating the distance of the target object.

Further, the measurement method according to the present invention provides a sampling included in a sampling data sequence sampled to detect a reflection time from when an ultrasonic wave having the predetermined frequency is transmitted until it is reflected by a target object and received. Fast Fourier transform is applied to the sampling data sequence obtained by dividing the entire data segment into minute segments and repeatedly arranging the sampling data sequence consisting of the sampling data existing in each minute segment. Thus, the spectrum intensity of the frequency band to which the predetermined frequency of the reflected wave received in the minute section belongs is calculated.
As a result, the intensity of the frequency band to which the predetermined frequency calculated for the reflected wave belongs can be detected with high accuracy, and the peak position can be obtained with high accuracy, so that the distance to the target object can be measured with high accuracy. Can do. Furthermore, a measurement method having resistance against mixing of white noise is provided.

On the other hand, the measuring apparatus according to the present invention includes a first ultrasonic transmission unit that continuously outputs ultrasonic waves of the first frequency over a predetermined period, and a first ultrasonic wave that outputs ultrasonic waves of the second frequency in a pulse shape. 2 ultrasonic transmission units, ultrasonic reception units transmitted from the first and second ultrasonic transmission units, and reflected waves from the target object related to the received ultrasonic waves of the first and second frequencies. A sampling unit for sampling, a relative velocity calculation unit for calculating a relative velocity of the target object based on a sampling data string related to the sampled ultrasonic waves of the first frequency, and sampling data related to the sampled ultrasonic waves of the second frequency A reflection time calculation unit that detects one or a plurality of reflection times from when the ultrasonic wave of the second frequency is transmitted based on the sequence to when it is reflected by the target object and received, and one or more detected Based on the reflection time, it is obtained so as to have to calculate the number and depth of the step on the surface of the distance or the object, to the object, the distance and the difference in level calculation unit.
Accordingly, it is possible to measure the relative speed of the target object, the distance to the target object, and even the surface shape of the target object using a relatively simple technical configuration. In particular, it is possible to accurately measure the distance to the target object positioned obliquely with respect to the measuring device.

In the measuring apparatus according to the present invention, the second ultrasonic wave transmitting unit outputs ultrasonic waves of the second frequency for approximately one wavelength.
Accordingly, if the reflection times of the plurality of reflected waves reflected from the surface portions having different heights on the surface of the target object are shifted by a time corresponding to approximately one wavelength of the ultrasonic wave, the ultrasonic wave receiving unit A plurality of reflected waves can be received separately without being superimposed, and the resolution related to the calculation of the difference in height (depth of the step) between different surface portions can be improved.

Further, in the measuring apparatus according to the present invention, the distance and step calculation unit corrects the distance to the target object or the depth of the step on the surface of the target object using the relative speed calculated by the relative speed calculation unit. To do.
Thereby, the distance to the target object or the depth of the step on the surface of the target object can be calculated with higher accuracy.

The measurement apparatus according to the present invention further includes a fast Fourier transform processing unit that performs a fast Fourier transform process on a sampling data sequence from the target object related to the ultrasonic wave of the first or second frequency, and the fast Fourier transform process. The result of the unit is used for processing in the relative speed calculation unit or the distance and step calculation unit, respectively.
As a result, the frequency resolution of the frequency spectrum calculated for the reflected wave related to the ultrasonic wave of the first frequency is increased, and the peak frequency related to the reflected wave can be detected more accurately. The speed resolution relating to the calculation of the relative speed can be improved. Further, the frequency resolution of the frequency spectrum calculated for the reflected wave from the target object is enhanced, and it is possible to more accurately detect a minute section in which the reflected wave related to the ultrasonic wave of the second frequency is received. Thus, errors related to the calculation of the distance to the target object can be reduced.

The measuring apparatus according to the present invention further includes a window function processing unit for applying a window function to a sampling data string from the target object related to the ultrasonic wave of the first or second frequency, and the window function processing unit Is output to the fast Fourier transform processing unit.
As a result, it is possible to reduce the error of the frequency spectrum calculated for the reflected wave related to the ultrasonic wave of the first frequency and to detect the peak frequency related to the reflected wave more accurately. An error related to the calculation of the relative speed can be reduced. In addition, since it is possible to reduce the error of the frequency spectrum calculated for the reflected wave from the target object, it is possible to detect a minute section in which the reflected wave related to the ultrasonic wave of the second frequency is received with higher accuracy. Further, it is possible to further reduce errors related to the calculation of the distance to the target object.

The measuring device according to the present invention includes an ultrasonic transmission unit that outputs ultrasonic waves of a specific frequency in a pulse shape, an ultrasonic reception unit that is transmitted from the ultrasonic transmission unit, and an ultrasonic wave that is received at the specific frequency. A sampling unit that samples a reflected wave from the target object related to the sound wave, and an ultrasonic wave of the frequency is transmitted based on the sampled data sequence related to the sampled ultrasonic wave of the specific frequency and then reflected and received by the target object A distance calculation unit that detects a reflection time until the target object is detected and calculates a distance to the target object based on the detected reflection time.
This makes it possible to measure the distance to the target object using a relatively simple technical configuration. In particular, it is possible to accurately measure the distance to the target object positioned obliquely with respect to the measuring device.

  In the measuring apparatus according to the present invention, the ultrasonic wave transmission unit outputs the ultrasonic wave having the specific frequency for approximately one wavelength. As a result, if the reflection time of the reflected wave reflected on the surface of the target object is shifted by a time corresponding to approximately one wavelength of the ultrasonic wave, the spectral intensity in the frequency band of the emitted ultrasonic wave is reduced in the ultrasonic wave receiving unit. Since the time resolution when searching can be improved, the resolution can be improved when calculating the distance of the target object.

The measurement apparatus according to the present invention further includes a fast Fourier transform processing unit that performs a fast Fourier transform processing on a sampling data string from the target object related to the ultrasonic wave of the specific frequency, and the result of the fast Fourier transform processing unit is obtained. This is used for processing in the distance calculation unit. As a result, the intensity of the frequency band to which the predetermined frequency calculated for the reflected wave belongs can be detected with high accuracy, and the peak position can be obtained with high accuracy, so that the distance to the target object can be measured with high accuracy. Can do. Furthermore, a measuring apparatus having resistance against mixing of white noise is provided.

In addition, an automobile according to the present invention includes a vehicle body and the measurement device, and the measurement device is attached to a front end and a rear end of a left side surface and / or a right side surface of the vehicle body.
Thereby, since the measuring device is provided, the distance to the wall surface and the like can be measured. In particular, even when the measuring device and the wall surface are inclined, it is possible to measure with high accuracy. Can be done.

  In addition, the automobile according to the present invention is one in which the measuring device is attached so that the ultrasonic radiation direction of the measuring device is perpendicular to the left side surface or the right side surface. As a result, the distance from the wall surface can be accurately measured, and the garage of the automobile can be easily and safely stored.

Further, the method of putting a car into a garage according to the present invention is a garage putting method having a wall surface having a step near the entrance, wherein the distance and step to the wall surface are measured by the measuring device of the car. The measurement is continuously performed, and the handle is operated when the state changes from a state where no step is detected to a state where a step is detected.
As a result, the distance to the wall surface and the step are continuously measured, and the steering wheel is operated when the step changes from the state where the step is not detected to the state where the step is detected. It can be done safely.

  According to the present invention, there is an effect that the distance to the target object can be accurately measured using a relatively simple technical configuration. In addition, there is an effect that it is possible to accurately measure the distance to the target object that is positioned obliquely with respect to the measuring device.

It is a figure which shows the distance measurement with respect to the object located diagonally. It is a figure explaining the distance measurement with respect to the object located diagonally. It is a block diagram which shows the structure of the measuring apparatus which implement | achieves the measuring method by Embodiment 1 thru | or 3. It is a timing chart which shows the method of producing | generating the electrical signal of an ultrasonic frequency with a PWM signal generator. It is a figure which shows the time passage of the frequency of the ultrasonic wave output from a speaker. 3 is a flowchart illustrating a measurement method according to Embodiment 1. It is a flowchart which shows the calculation method of the relative speed of a target object. It is a figure which shows the increase process of the sampling data in a sampling data sequence. It is a figure which shows the frequency spectrum of a reflected wave. It is a flowchart which shows the calculation method of the distance to a target object, the number of steps on the surface of a target object, and the depth. It is a figure which shows the increase process of the sampling data in a sampling data sequence. It is a figure which shows the aspect of the measurement of the level | step difference on the surface of a target object. It is a figure which shows the time passage of the spectrum intensity | strength of the 20 kHz band which concerns on the reflected wave received. 6 is a flowchart illustrating a measurement method according to Embodiment 2. It is a block diagram which shows the structure of the measuring apparatus which implement | achieves the measuring method by Embodiment 3. FIG. 10 is a flowchart illustrating a measurement method according to Embodiment 3. 12 is a flowchart illustrating a method for calculating a distance to a target object according to the third embodiment. FIG. 10 is a diagram illustrating a distance calculation method according to a third embodiment. It is a figure which shows the example which implemented the measurement by this invention with respect to the inclined target object. It is a figure which shows the measured value of (theta) 1 and (theta) 2 by 1st and 2nd embodiment. It is a figure which shows the comparison by three methods of (theta) 2 measured value. It is a figure which shows the garage of the motor vehicle by the method of this invention. It is a figure which shows the detection condition of the reflected wave at the time of entering the garage of a motor vehicle. It is a flowchart which shows the procedure of garage entry.

Explanation of symbols

21: Measuring device
22: Ultrasonic transmitter 23: Ultrasonic receiver 24: Target object
25: First surface portion 26: Second surface portion
29: Flat plate
32: Mirror image ultrasonic transmitter
100, 150: Measuring device
101: Microcomputer
102: Personal computer 103: D / A converter
104: PWM signal generator
105: Multiplier
106, 109: Amplifier
107: Speaker 108: Microphone 110, 160: Sampling unit 111, 161: Memory 130: Relative speed calculation unit 135: Reflection time calculation unit 140: Distance and step calculation unit 145: Distance calculation unit 154: Window function processing unit 155: FFT Processing unit 157: Ultrasonic transmitter 158: Ultrasonic receiver 170: Control unit 204: Car body 205: Road 210: Car 220 equipped with measuring device 220: Garage 225: Wall 230: Step 241: Device attached to the front end of the car body 242: Device attached to the rear end of the vehicle body 249: Ultrasonic radiation direction

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
Embodiment 1 FIG.
FIG. 3A is a block diagram showing the configuration of the measuring apparatus 100 that realizes the measuring method according to this embodiment.
The microcomputer 101 performs processing for generating an electrical signal having an ultrasonic frequency, sampling processing for an electrical signal obtained by piezoelectric conversion of a reflected wave from a target object, and the like. The microcomputer 101 A / D (analog / digital) converts the signal received by the microphone 108 and performs sampling processing, a memory 111 for storing the sampled data, and D / A (digital / analog). ) Converter 103 and PWM (Pulse Width Modulation) signal generator 104.

  The D / A converter 103 of the microcomputer 101 converts, for example, an 8-bit digital signal into an analog signal. Multiplier 105 outputs an electric signal obtained by multiplying the electric signal output from D / A converter 103 and the electric signal output from PWM signal generator 104. The amplifier 106 amplifies the electrical signal output from the multiplier 105. The speaker 107 piezoelectrically converts the electrical signal output from the amplifier 106 and outputs an ultrasonic wave.

In addition, the microphone 108 that outputs an electric signal receives an ultrasonic wave (reflected wave) reflected from an object to be measured and piezoelectrically converts it, and the amplifier 109 amplifies the electric signal output from the microphone 108. The sampling unit 110 converts the analog signal output from the amplifier 109 into, for example, a 10-bit digital signal value at a predetermined sampling interval. The memory 111 has a function of sequentially storing the digital signal values sampled by the sampling unit 10 and is a RAM having a capacity of 2 kbytes, for example.
The personal computer 102 inputs the sampling data string from the microcomputer 101 and applies FFT (Fast Fourier Transform) processing or the like to calculate the speed of the target object, the distance to the target object, and the like. As shown in FIG. 3B, the personal computer 102 includes a relative speed calculation unit 130, a reflection time calculation unit 135, and a distance and level difference calculation unit 140. Further, the personal computer 102 has an FFT processing unit 155 for applying the FFT processing when the relative speed calculation unit 130 and / or the reflection time calculation unit 135 performs processing. In order to apply the FFT processing after applying the window function to the sampling data string, a window function processing unit 154 is provided as necessary. The sampling data string stored in the memory 111 of the microcomputer 101 is sent to the relative speed calculation unit 130 and the reflection time calculation unit 135 of the personal computer 102, and the FFT processing unit 155 applies the FFT processing to make the relative to the target object. Calculate speed and reflection time. If necessary, the window function processing unit 154 performs window function processing. In addition, from the result calculated by the reflection time calculation unit 135, the distance and level difference calculation unit 140 may also use the result calculated by the relative speed calculation unit 130 and the distance to the target object and the target object. The number and depth of steps on the surface of the substrate are calculated.

  FIG. 4 is a timing chart showing a method for generating an electrical signal having an ultrasonic frequency by the PWM signal generator 104. The microcomputer 101 includes a timer counter, a clock signal generator, and registers A and B (not shown). The count value of the timer counter is incremented by 1 each time a rising edge or a falling edge of the clock signal generated from the clock signal generator is detected. The PWM signal generator 4 changes the output voltage value to 0 V when the count value of the timer counter matches the numerical value stored in the register B, and outputs the output voltage when the count value of the timer counter matches the numerical value stored in the register A. The value is changed to a predetermined voltage value, for example, 5V.

    The timer counter is configured to return the count value to zero in order to reset the counting process when the count value matches the numerical value stored in the register A. In such an apparatus configuration, by making the numerical value stored in the register A twice the numerical value stored in the register B, the PWM signal generator 104 outputs a rectangular wave electric signal having a duty ratio of 50%. can do. Furthermore, a rectangular wave electric signal having a desired frequency can be obtained by appropriately selecting numerical values stored in the register A and the register B according to the frequency of the clock signal generated from the clock signal generator. . As shown in FIG. 4, by storing appropriate numerical values in the register A and the register B, it is possible to generate an electrical signal having an ultrasonic frequency with a period of 25 μsec and a frequency of 40 kHz. In addition, the numerical value stored in the register A and the register B is set to be twice the numerical value stored when generating the electrical signal having the ultrasonic frequency of 40 kHz, so that the ultrasonic wave having a period of 50 μs and a frequency of 20 kHz is obtained. It is possible to generate a frequency electrical signal.

    However, if rectangular ultrasonic waves are suddenly output from the speaker 107, audible sound waves are mixed. In order to solve such a problem, when the output of the electrical signal of the ultrasonic frequency from the PWM signal generator 104 is started, the half-sine signal is sent from the D / A converter 103 so as to be synchronized with the electrical signal. Output a wave. In the multiplier 105, the rectangular wave electric signal output from the PWM signal generator 104 and the half sine wave electric signal output from the D / A converter 103 are multiplied, thereby obtaining a rectangular ultrasonic frequency. A wave electric signal is AM-modulated by a half-sine wave. Thereby, the first part of the electrical signal of the rectangular wave of the ultrasonic frequency is blunted, and it becomes possible to reduce the sound wave output in the audible range.

  Next, a measurement method using this system will be described. FIG. 5 is also a diagram showing the time lapse of the frequency of the ultrasonic wave output from the speaker 107. As shown in FIG. 5, the speaker 107 continuously outputs a 40 kHz ultrasonic wave over a period of 2 msec, and then outputs a 20 kHz ultrasonic wave in a pulse shape over a period of 50 μsec. 50 μs corresponds to one wavelength of 20 kHz ultrasonic waves. In this invention, the relative velocity of a target object is calculated by calculating | requiring the frequency spectrum of the reflected wave from the target object which concerns on the 40kHz ultrasonic wave output continuously. Further, by detecting the reflection time defined as the time from when the ultrasonic wave of 20 kHz is transmitted until it is reflected and received by the target object for each surface portion having a different height on the surface of the target object, The distance to the target object and the number and depth of steps on the surface of the target object are calculated.

  FIG. 6 is a flowchart showing a measurement method according to Embodiment 1 of the present invention. As described above, 40 kHz ultrasonic waves are continuously output over a period of about 2 milliseconds (step S1). Next, the reflected wave from the target object related to the transmitted 40 kHz ultrasonic wave is sampled over a period of about 10 milliseconds (step S2). The ultrasonic receiver 108 converts the received ultrasonic wave into an electric signal. The sampling unit 110 samples the electrical signal amplified by the amplifier 9 at a sampling interval of 10 μs, converts it into 1024 digital signal values, and outputs the result. In order to obtain 1024 sampling data at a sampling interval of 10 μs, this sampling process takes about 10 milliseconds.

  The memory 111 sequentially stores 1024 sampling data. After all the sampling data related to the first sampling process is stored in the memory 111, a sampling data string composed of all the sampling data stored in the memory 111 is transferred to the relative speed calculation unit 130 of the personal computer 102. The relative speed calculation unit 130 calculates the relative speed of the target object based on the transferred sampling data sequence (step S3).

  Here, the calculation of the relative speed of the target object performed by the relative speed calculation unit 130 will be described in detail. FIG. 7 is a flowchart showing a method for calculating the relative speed of the target object. In the first embodiment, the number of sampling data included in the sampling data string is increased in order to increase the frequency resolution of the frequency spectrum calculated for detecting the peak frequency of the reflected wave (step S11). FIG. 8 is a diagram showing an increase process of sampling data in the sampling data string. As shown in FIG. 8, 64512 “0” s are arranged after the sampling data sequence composed of 1024 sampling data, thereby generating a sampling data sequence composed of 65536 sampling data. If a sampling data string composed of 65536 sampling data is obtained, a Hanning window function is applied to the sampling data string (step S12). Next, FFT (Fast Fourier Transform) is applied to the sampling data sequence multiplied by the Hanning window function to calculate a frequency spectrum related to the reflected wave (step S13). If the peak frequency is detected, the relative speed of the target object is calculated based on the peak frequency (step S14).

By increasing the number of sampling data included in the sampling data string from 1024 to 65536, the frequency resolution is improved from 100 Hz to 1.5 Hz. Further, as the frequency resolution is increased, the speed resolution related to the relative speed of the target object is also improved from 87 cm / second to 1.3 cm / second accordingly. FIG. 9 is a diagram showing the frequency spectrum of the reflected wave. As shown in FIG. 9, the peak frequency of the reflected wave deviates from 40 kHz due to the Doppler effect resulting from the motion of the target object. Here, the relative speed of the object to Vs, the sound velocity c, the frequency of the ultrasonic wave transmitted to f ₀ from the speaker 107, when the reflected wave peak frequency receive f ₁ to the microphone 108, of the target object relative The speed Vs is given by the following equation (1).
Vs = c · (f ₁ −f ₀ ) / (f ₁ + f ₀ ) (1)

  As shown in FIG. 5, after continuously outputting 40 kHz ultrasonic waves over a period of about 2 msec, pulsed ultrasonic waves of 20 kHz are output over a period of 50 μsec (step S <b> 4). If pulsed ultrasonic waves of 20 kHz are output, the reflected wave from the target object is sampled over a period of 10 milliseconds immediately after that (step S5). Also in this case, in order to calculate the frequency spectrum of the reflected wave, the sampling unit 110 samples the electrical signal amplified by the amplifier 109 at a sampling interval of 10 μs, as in the first sampling process. Convert to 1024 digital signal values and output. That is, after outputting a 20 kHz ultrasonic wave, sampling of the reflected wave is continued for a period of about 10 milliseconds.

  The memory 111 sequentially accumulates 1024 sampling data related to the second sampling process. Note that since the 1024 sampling data accumulated in the memory 111 by the first sampling process to calculate the relative speed of the target object have already been transferred to the relative speed calculation unit 130 of the personal computer 2, the current sampling is performed. Data storage may be performed in such a manner that the memory element storing the previous sampling data is overwritten. After all the sampling data related to the second sampling process is accumulated in the memory 111, the sampling data string composed of the sampling data accumulated in the memory 111 is transferred to the reflection time calculation unit 135 of the personal computer 102. The reflection time calculation unit 135 calculates the reflection time based on the transferred sampling data sequence, and the distance and step calculation unit 140 calculates the distance to the target object and the number and depth of steps on the surface of the target object. Calculate (step S6).

  Here, calculation of the distance to the target object, the number of steps on the surface of the target object, and the depth performed by the reflection time calculation unit 135 and the distance and level difference calculation unit 140 will be described. FIG. 10 is a flowchart illustrating a method of calculating the distance to the target object, the number of steps on the surface of the target object, and the depth. If a sampling data string composed of 1024 sampling data is obtained, the observation section composed of the sampling data string is divided into minute sections composed of five sampling data (step S21). As described above, since the sampling interval is 10 μsec, the length of the minute section is 50 μsec. This corresponds to one wavelength of a signal having an ultrasonic frequency of 20 kHz. That is, the minute interval is set as an interval having a minimum time width in which a 20 kHz frequency spectrum can be detected by FFT.

  When the division into the minute sections is completed, it is detected whether or not the reflected wave related to the 20 kHz ultrasonic wave is received in order for each minute section. Here again, the number of sampling data included in the sampling data string is increased for each minute section in order to increase the frequency resolution of the frequency spectrum calculated for the reflected wave received in the minute section (step S22). . FIG. 11 is a diagram showing an increase process of sampling data in the sampling data string. As shown in FIG. 11, a sampling data string composed of 2048 sampling data is generated by repeatedly arranging a sampling data string composed of five sampling data for each minute section. If a sampling data string composed of 2048 sampling data is obtained, a Hanning window function is applied to the sampling data string (step S23). An FFT is applied to the sampling data string multiplied by the Hanning window function to calculate a frequency spectrum related to the reflected wave (step S24).

  If the frequency spectrum is calculated, it is determined whether or not the peak frequency in the minute section is about 20 kHz (step S25). If the peak frequency is about 20 kHz, it is recognized that the reflected wave related to the 20 kHz ultrasonic wave output in a pulse shape is received in the minute section. Therefore, the position on the time axis of the minute section is specified. Then, the reflection time related to the 20 kHz ultrasonic wave is obtained (step S26). This detects the time (reflection time) that has elapsed since the 20 kHz pulsed ultrasonic wave was output until it was reflected by the target object and received.

FIG. 12 is a diagram illustrating an aspect of measuring a step on the surface of the target object. In the measurement apparatus 21, the ultrasonic transmission unit 22 is provided as a speaker 107, for example, and the ultrasonic reception unit 23 is provided as a microphone 108, for example. In addition, the target object 24 to be measured has a first surface portion 25 and a second surface portion 26 of the target object 24 that is positioned with a step from the first surface portion 25. . Since the distance from the measuring device 21 to the first surface portion 25 is different from the distance to the second surface portion 26, the ultrasonic wave transmitted from the ultrasonic transmitter 22 is reflected by the first surface portion 25. The reflection time T ₁ until the ultrasonic wave reception unit 23 receives the signal and the ultrasonic wave transmitted from the ultrasonic wave transmission unit 22 is reflected by the second surface unit 26 and received by the ultrasonic wave reception unit 23. the a reflection time T ₂ of the results is time lag.

  FIG. 13 is a diagram showing the time lapse of the spectrum intensity in the 20 kHz band related to the received reflected wave. In FIG. 13, the spectrum intensity in the 20 kHz band is shown for each minute section. In this embodiment, since the minute section is configured to have the minimum section width (50 μsec) that can detect the peak frequency of 20 kHz, the super section reflected from the different surface portions 25 and 26 of the target object 24. It is possible to reduce the lower limit value of the step depth required to enable reception of sound waves in different micro sections, and to greatly improve the resolution of the step depth.

If it is not determined in step S25 that the peak frequency is about 20 kHz, and after the processing in step S26 is completed, whether there is a minute interval in which the reflected wave related to the 20 kHz ultrasonic wave should be detected. It is determined whether or not (step S27). If it is determined that the minute section remains, the process proceeds to step S22 in order to detect the reflected wave related to the 20 kHz ultrasonic wave for the next minute section. If it is determined that the detection of the reflected wave related to the 20 kHz ultrasonic wave is completed for all the minute sections, the target object is reached based on one or a plurality of reflection times (T ₁ , T ₂ ,...). And the number and depth of steps on the surface of the target object are calculated (step S28).

As shown in FIG. 13, taking as an example a case where a reflected wave having a peak frequency of about 20 kHz is detected in two minute sections by the reflection time calculation unit 135, the distance to the target object by the distance and step calculation unit 140, and A method for calculating the number and depth of steps on the surface of the target object will be described. Here, the reflection time from when the ultrasonic wave of 20 kHz is transmitted to T ₁ until it is reflected and received by the first surface portion 25, the second surface portion after the ultrasonic wave of T ₂ is transmitted to T ₂ The reflection time until the light is received after being reflected by 26, R is the distance to the target object. The distance R to the target object is given by the following equation (2) by compensating for the influence of the relative speed Vs of the target object calculated by the relative speed calculation unit 130.
_{R = (T 1/2)} (c-Vs) (2)
By substituting equation (1) into equation (2), the distance R to the target object is also given by equation (3) below.
R = T ₁ · c · f ₀ / (f ₁ + f ₀ ) (3)

Further, the depth H of the step is given by the following equation (4).
H = (T ₂ −T ₁ ) · c · f ₀ / (f ₁ + f ₀ ) (4)
In the above example, the number of steps is one because there are two minute sections in which the reflected wave related to the 20 kHz ultrasonic wave is detected. The number of steps detected by the present invention is not limited to one. For example, if there are three minute sections in which reflected waves are detected, the number of steps is two, and the minute steps in which reflected waves are detected. If there are four sections, the number of steps will be three. The depth of each step is calculated in the same manner using the above equation (4).

  By using the measurement method as described above, the relative velocity of the target object can be measured with a velocity resolution of about 1.5 cm / sec, with 3.0 cm / sec as the lower limit. The measurement error was about 15 percent. Moreover, about the measurement of the depth of a level | step difference, the measurement accuracy of about 2 cm was able to be obtained.

As described above, in the measurement method according to the first embodiment, a 40 kHz ultrasonic wave is continuously output over a period of about 2 milliseconds, and a reflected wave from a target object related to the 40 kHz ultrasonic wave is about 10 milliseconds. A step of sampling over a period of time, a step of calculating a relative velocity of the target object based on a sampling data string composed of 1024 sampling data sampled at the first time, and an ultrasonic wave having a frequency of 40 kHz was continuously output. A step of outputting a 20 kHz ultrasonic wave in a pulse form later, and a 40 kHz ultrasonic wave immediately after outputting a 20 kHz ultrasonic wave in a pulse form after transferring a sampling data string related to the first sampling process to the personal computer 2 The reflected wave from the target object related to the 20 kHz ultrasonic wave is about 10 ms. One or a plurality of reflections from when a 20 kHz ultrasonic wave is transmitted to a target object after being transmitted based on a sampling data sequence composed of 1024 sampling data samples sampled for the second time Since it is configured to include a step of detecting time and a step of calculating the distance to the target object and the number and depth of steps on the surface of the target object based on the detected one or more reflection times. Using a relatively simple technical configuration, it is possible to measure the relative speed of the target object, the distance to the target object, and even the surface shape of the target object.
In particular, it is possible to accurately measure the distance to the target object positioned obliquely with respect to the measuring apparatus.

In addition, since the ultrasonic wave of 20 kHz is output only for one wavelength, the reflection times T ₁ related to a plurality of reflected waves reflected from the surface portions 25 and 26 having different heights on the surface of the target object, If T ₂ is shifted by a time corresponding to approximately one wavelength of the 20 kHz ultrasonic wave, the ultrasonic wave receiving unit 23 can separate and receive these plural reflected waves without superimposing them. The resolution related to the calculation of the difference in height between the surface portions 25 and 26 (step depth H) can be improved.

  Further, the observation section given as a sampling data string composed of 1024 sampling data sampled the second time is divided into minute sections given as detection units of reflected waves, and the length of each minute section is set to 20 kHz. Since the section having the minimum time width in which the frequency spectrum related to the 20 kHz ultrasonic wave can be detected is set as the minute section. It is possible to reduce the lower limit value of the depth H of the step that enables a plurality of reflected waves reflected from the surface portions 25 and 26 having different heights on the surface of the surface to be received in different minute sections, The resolution related to the calculation of the depth H of the step can be improved.

  Further, using the relative velocity of the target object calculated based on the sampling data sequence consisting of 1024 sampling data sampled the first time, the sampling data sequence consisting of 1024 sampling data sampled the second time is used. Since it is configured to correct the calculated distance to the target object and the depth of the step on the surface of the target object, the distance to the target object and the depth of the step on the surface of the target object can be more accurately determined. Can be calculated.

  Further, fast Fourier transform is applied to a sampling data sequence consisting of 65536 sampling data obtained by arranging 64512 zeros after a sampling data sequence consisting of 1024 sampling data sampled at the first time. Therefore, since the frequency spectrum of the reflected wave from the target object related to the ultrasonic wave of 40 kHz is calculated, the frequency resolution of the frequency spectrum calculated for the reflected wave is increased, and the peak frequency related to the reflected wave is increased. Since it becomes possible to detect with higher accuracy, it is possible to improve the speed resolution related to the calculation of the relative speed of the target object.

  After applying a Hanning window function to a sampling data sequence consisting of 65536 sampling data obtained by arranging 64512 zeros after a sampling data sequence consisting of 1024 sampling data sampled for the first time Since the fast Fourier transform is applied, it is possible to reduce the error of the frequency spectrum calculated for the reflected wave related to the 40 kHz ultrasonic wave and detect the peak frequency related to the reflected wave more accurately. Therefore, an error related to the calculation of the relative speed of the target object can be reduced.

  In addition, the observation section given as a sampling data sequence composed of 1024 sampling data sampled the second time is divided into minute sections for every five sampling data, and each minute section exists in the minute section. By applying a fast Fourier transform to a sampling data sequence consisting of 2048 sampling data obtained by repeatedly arranging sampling data sequences consisting of five sampling data, the frequency of the reflected wave received in the minute interval Since the spectrum is calculated, the frequency resolution of the frequency spectrum calculated for the reflected wave related to the ultrasonic wave of 40 kHz and the ultrasonic wave of 20 kHz is increased, and the minute section in which the reflected wave related to the ultrasonic wave of 20 kHz is received. Can be detected more accurately Since the, it is possible to reduce the error according to the calculation such as the distance to the object.

  Further, after applying a Hanning window function to a sampling data sequence consisting of 2048 sampling data obtained by repeatedly arranging sampling data sequences consisting of 5 sampling data existing in a minute section, fast Fourier transform is applied. Since it is configured as described above, the error of the frequency spectrum calculated for the reflected wave related to the ultrasonic wave of 40 kHz and the ultrasonic wave of 20 kHz is reduced, and the minute section in which the reflected wave related to the ultrasonic wave of 20 kHz is received is more accurately. Since it becomes possible to detect, the error concerning calculation of the distance to the target object and the like can be further reduced.

  In the first embodiment, the relative velocity of the target object is calculated, and then a 20 kHz pulsed ultrasonic wave is output. The order in which each step is executed is shown in FIG. It is not limited to the mode shown in the flowchart. For example, by storing the sampling data transferred to the storage means in the personal computer 102, the relative speed of the target object, the distance to the target object, and the surface of the target object after all the sampling processes are completed You may comprise so that the number and depth of a level | step difference may be calculated collectively. Moreover, you may comprise so that the process of outputting a 20-kHz pulse-form ultrasonic wave and the process of calculating the relative velocity of a target object may be performed in parallel.

  Further, 40 kHz is used as the frequency of the ultrasonic wave that is continuously output to calculate the relative velocity of the target object, and the distance to the target object and the number and depth of steps on the surface of the target object are calculated. 20 kHz is used as the frequency of ultrasonic waves output in a pulsed manner, but the frequency of ultrasonic waves used is not limited to these frequencies, and ultrasonic waves of various frequencies can be used. Needless to say. The period during which 40 kHz ultrasonic waves are continuously output is not limited to 2 milliseconds, and the period required for the first and second sampling processes is not limited to 10 milliseconds. In the first sampling process and the second sampling process, the number of data to be sampled is not limited to 1024 each. Furthermore, in order to improve the frequency resolution, the number of data in the sampling data string obtained by increasing the number of sampling data included in the sampling data string related to the first sampling process is not limited to 65536. The number of data in the sampling data string obtained by increasing the number of sampling data included in the sampling data string composed of the five sampling data existing in the minute section is not limited to 2048. The frequency, sampling interval, sampling period, the number of sampling data, the increase in the number of sampling data, etc. used for the ultrasonic, the CPU, memory, sampling unit, A / D converter, It will be understood that it can be appropriately changed according to the performance of a device such as a D / A converter or an oscillator.

  In the first embodiment, the frequency of ultrasonic waves (20 kHz) output in a pulse form is set lower than the frequency of ultrasonic waves (40 kHz) output continuously. It is good also as a structure made higher than the frequency of the ultrasonic wave which outputs the frequency of a sound wave continuously. The higher the frequency of the ultrasonic wave, the shorter the cycle. Therefore, it becomes possible to shorten the time width of the minute section for detecting the ultrasonic wave of the frequency. Since the resolution for calculating the depth H of the step becomes higher as the minute interval becomes shorter, it is preferable to set the frequency of the ultrasonic wave to be output in a pulse shape higher.

  Furthermore, in the above-described first embodiment, the measurement apparatus shown in FIG. 3 is configured. However, the measurement apparatus is not limited to such an apparatus form, and can be realized in various forms. It is. For example, it is of course possible to form a dedicated measuring device by integrating means for realizing the respective steps described in the flowchart shown in FIG.

Embodiment 2. FIG.
Next, a measurement method according to Embodiment 2 of the present invention will be described. Compared with the measurement method according to the first embodiment, the measurement method according to the second embodiment is based on a single sampled data sequence sampled over a period of about 10 msec. And the number and depth of steps on the surface of the target object are calculated. Note that the configuration and the like of the measurement apparatus that implements the measurement method according to the second embodiment are the same as those of the first embodiment, and thus description thereof is omitted.

  FIG. 14 is a flowchart showing a measurement method according to Embodiment 2 of the present invention. First, a 40 kHz ultrasonic wave is continuously output from the ultrasonic transmitter 107 over a period of 2 msec (step S31). As for the time lapse related to the output of the ultrasonic wave, the mode shown in FIG. After the 40 kHz ultrasonic wave is continuously output, a 20 kHz pulsed ultrasonic wave is output from the ultrasonic transmitter 107 over a period of 50 μs (step S32). As described above, the output time of 50 μs corresponds to one wavelength of 20 kHz ultrasonic waves.

  Based on the output mode as shown in FIG. 5, the 40 kHz ultrasonic wave received by the ultrasonic receiver 108 in response to the output of the continuous 40 kHz ultrasonic wave and the pulsed 20 kHz ultrasonic wave. And the reflected wave from the target object which concerns on a 20 kHz ultrasonic wave is sampled in the sampling part 110 over the period of 10 milliseconds (step S33). For the sampling period of 10 milliseconds, the frequency spectrum related to the 40 kHz ultrasonic wave that is output continuously and the frequency spectrum related to the 20 kHz ultrasonic wave that is output in a pulsed manner have a predetermined accuracy or higher. It is necessary to appropriately set the start (or end) of sampling so that it can be detected with accuracy.

  For example, when the reflection time of the ultrasonic wave is 2 milliseconds or more, sampling of the reflected wave from the target object is started immediately after the 20 kHz pulsed ultrasonic wave is output, as in the first embodiment. You may comprise. In addition, when the ultrasonic reflection time is less than 2 milliseconds, if sampling is not started before the 20 kHz pulsed ultrasonic wave is output, a large part of the 40 kHz ultrasonic wave that is continuously output is generated. There may be a case where the ultrasonic wave receiving unit is reached before the sampling is started and the frequency spectrum cannot be calculated with sufficient accuracy. However, when the sampling start is set to an arbitrary time before outputting the 20 kHz pulsed ultrasonic wave, the time from the start of sampling until the 20 kHz pulsed ultrasonic wave is output is clarified. It is necessary to configure the apparatus so that it can be identified. Such an apparatus configuration is necessary for specifying the reflection time of a 20 kHz pulsed ultrasonic wave, and can be realized by using, for example, a timer counter in the microcomputer 1.

  Over the sampling period, the microphone 108 receives the ultrasonic wave reflected from the target object, and converts the received ultrasonic wave into an electrical signal. The sampling unit 110 performs A / D conversion on the electrical signal amplified by the amplifier 109, samples it at a sampling interval of 10 μs, converts it into 1024 digital signal values, and outputs it. In order to obtain sampling data at an interval of 10 μs, this sampling process takes about 10 milliseconds. The memory 111 sequentially stores 1024 sampling data. After all the sampling data related to the sampling process is accumulated in the memory 111 of the microcomputer 1, the sampling data string composed of all the sampling data accumulated in the memory 111 is the relative velocity calculation unit 130 and the reflection time calculation of the personal computer 102. Is transferred to the unit 135.

  The relative speed calculation unit 130 calculates the relative speed of the target object based on the transferred sampling data sequence (step S34). As described above, based on this sampling data string, the distance to the target object and the number of steps on the surface of the target object and the depth are calculated together with the relative speed of the target object. The data related to the sampling data string is stored in a predetermined storage area in a memory (not shown) separately provided in the personal computer 102 and calculated by the relative velocity calculation unit 130 and the reflection time calculation unit 135. It is preferable to configure to read appropriately.

  The calculation method of the relative speed of the target object performed by the relative speed detection unit 130 is performed using the same algorithm as the relative speed calculation method according to the first embodiment shown in FIG. Again, in order to increase the frequency resolution of the frequency spectrum calculated in order to detect the peak frequency of the reflected wave, as shown in FIG. 8, there are 64512 data after the sampling data string consisting of 1024 sampling data. By arranging “0”, a sampling data string composed of 65536 sampling data is generated. If a sampling data string composed of 65536 sampling data is obtained, a Hanning window function is applied to the sampling data string. Next, FFT is applied to the sampling data string multiplied by the Hanning window function to calculate a frequency spectrum related to the reflected wave. If the peak frequency is detected, the relative speed of the target object is calculated based on the peak frequency.

  After calculating the relative velocity of the target object, the reflection time calculation unit 135 calculates the reflection time based on the transferred sampling data sequence, and the distance and step calculation unit 140 calculates the distance to the target object and the surface of the target object. The number and depth of the upper steps are calculated (step S35). Regarding the calculation method of the distance to the target object, the number of steps on the surface of the target object, and the depth performed by the distance and step calculation unit 140, the calculation method of these numerical values according to the first embodiment shown in FIG. A similar algorithm is used. In this case as well, an observation section composed of a sampling data string composed of 1024 sampling data is divided into minute sections composed of five sampling data. As described above, since the sampling interval is 10 μs, the length of the minute section is set to be approximately equal to one wavelength (50 μs) of 20 kHz ultrasonic waves.

  In addition, in order to increase the frequency resolution of the frequency spectrum calculated for the reflected wave received in the minute section for each minute section, the number of sampling data included in the sampling data string as shown in FIG. To increase. That is, a sampling data string consisting of 2048 sampling data is generated by repeatedly arranging a sampling data string consisting of five sampling data for each minute section. If a sampling data string composed of 2048 sampling data is obtained, a Hanning window function is applied to the sampling data string. An FFT is applied to the sampling data string multiplied by the Hanning window function to calculate a frequency spectrum related to the reflected wave.

  If the frequency spectrum in each minute section is calculated, the position on the time axis of the minute section where the peak frequency is about 20 kHz is specified, and the reflection time related to the 20 kHz ultrasonic wave is obtained. As described above, sampling in the measurement method according to the second embodiment is not started immediately after a 20 kHz ultrasonic wave is transmitted. For this purpose, the position on the time axis at which the 20 kHz ultrasonic wave is transmitted and the position on the time axis of one or more minute sections having a peak frequency of about 20 kHz are identified, and one or more reflection times are obtained. Is calculated. The method for calculating the distance to the target object and the number and depth of steps on the surface of the target object based on one or a plurality of reflection times is the same as that of the first embodiment, and thus the description thereof. Is omitted.

  As described above, according to the measurement method according to the second embodiment, a 40 kHz ultrasonic wave is continuously output over a period of about 2 milliseconds, and an ultrasonic wave having a frequency of 40 kHz is continuously output and then 20 kHz. The target object according to the step of outputting the ultrasonic wave in the form of pulses and the ultrasonic wave having the frequency of 40 kHz and the ultrasonic wave having the frequency of 20 kHz according to outputting the ultrasonic wave having the frequency of 40 kHz and the ultrasonic wave having the frequency of 20 kHz. Sampling a reflected wave from 10 msec over a period of 10 milliseconds, calculating a relative velocity of the target object based on a sampling data string composed of 1024 sampled sampled data, and 1024 sampled sampling data A 20 kHz ultrasonic wave is transmitted based on a sampling data sequence consisting of Detecting one or a plurality of reflection times from the reflection to the target object until reception, and the distance of the target object and the number of steps on the surface of the target object based on the detected one or more reflection times And measuring the depth, and using a relatively simple technical configuration, measure the speed of the target object, the distance to the target object, and even the surface shape of the target object. Is possible. In addition, since it is sufficient to perform one sampling to calculate the distance to the target object as well as the relative speed of the target object and the number and depth of steps on the surface of the target object, This makes it possible to simplify sampling data storage processing, transfer processing, and the like in the RAM 111, and to simplify the system configuration of the measuring apparatus. In particular, it is possible to accurately measure the distance to the target object positioned obliquely with respect to the measuring apparatus.

  Note that the 20 kHz ultrasonic wave is output only for one wavelength, and the length of the minute section obtained by dividing the observation section made up of the entire sampling data string is substantially equal to one wavelength of the 20 kHz ultrasonic wave. To correct the distance to the target object and the depth of the step on the surface of the target object using the calculated relative speed of the target object, and the frequency for the observation section consisting of the entire sampling data string Applying a fast Fourier transform to a sampling data sequence consisting of 65536 sampling data obtained by arranging 64512 zeros after a sampling data sequence consisting of 1024 sampling data when calculating the spectrum, Window function for sampling data string consisting of 65536 sampling data Applying the Fast Fourier Transform after applying the data, from the 2048 sampling data obtained by repeatedly arranging the sampling data sequence consisting of 5 sampling data when calculating the frequency spectrum for a minute section consisting of 5 sampling data sequence Each effect obtained by applying the fast Fourier transform to the sampling data sequence comprising the above and applying the fast Fourier transform after applying the window function to the sampling data sequence comprising the 2048 sampling data described above Since is the same as in the first embodiment, the description thereof is omitted.

  Further, the order of executing the respective steps constituting the measurement method in order to realize the measurement method according to the second embodiment is not limited to the mode shown in the flowchart shown in FIG. For example, the step of calculating the relative velocity of the target object based on the sampling data sequence may be executed after the step of detecting one or a plurality of reflection times based on the sampling data sequence, and these steps may be performed in parallel. It is good also as a structure to perform to. Further, in the same manner as in the first embodiment, the ultrasonic frequency, sampling interval, sampling period, number of sampling data, number of increase in sampling data, etc. used in the measurement method according to the second embodiment are used. It will be understood that the CPU, memory, A / D converter, D / A converter, oscillator, and other devices incorporated in the apparatus can be appropriately changed. Furthermore, the measuring apparatus can take various apparatus forms as long as all the means for realizing the respective steps described in the flowchart shown in FIG. 14 are provided.

Embodiment 3 FIG.
Next, a measurement method according to Embodiment 3 of the present invention will be described. Compared with the measurement method according to the first and second embodiments, the measurement method according to the third embodiment transmits a single-frequency ultrasonic wave in the form of a pulse and generates a sampling data string sampled over a period of about 10 msec. Based on this, only the distance to the target object is calculated. For the configuration of the measuring apparatus that implements the measuring method according to the third embodiment, the apparatus used in the first embodiment and the second embodiment shown in FIG. 3 can be used. However, in this embodiment, only one necessary function is used because there is only one ultrasonic frequency, and the calculation of the relative velocity and the number of steps on the surface of the target object and the depth are not calculated. .

  Moreover, the apparatus which implements this embodiment can also take a structure like FIG. This configuration is simpler than the configuration of FIG. The apparatus 150 used in the present embodiment includes an ultrasonic transmitter 157 that is a transmission source of ultrasonic waves emitted at a predetermined single frequency toward a target object, and an ultrasonic receiver that receives ultrasonic waves reflected by the target object. 158, a sampling unit 160 for performing A / D (analog / digital) conversion on the signal received by the ultrasonic receiver 158 and performing sampling processing, a memory 161 for storing the sampled data, and ultrasonic waves of the frequency are transmitted. The distance calculation unit 145 and the distance calculation unit 145 calculate the distance to the target object based on the detected reflection time after detecting the reflection time until the target object is reflected and received. Controls the oscillation of the FFT processing unit 155 and the ultrasonic transmitter 157 that apply the FFT processing and the like by inputting the sampling data string, and also controls the entire apparatus And a control unit 170 of the fit. The sampling unit 160, the memory 161, the distance calculation unit 145, the FFT processing unit 155, and the control unit 170 can be installed in a computer and configured with hardware or software.

  The ultrasonic receiver 158 receives an ultrasonic wave (reflected wave) reflected from an object to be measured, and performs piezoelectric conversion to output an electric signal. Electrical signal amplifiers are provided as required. The sampling unit 160 converts the analog electrical signal output from the ultrasonic receiver 158 into, for example, a 10-bit digital signal value at a predetermined sampling interval. The memory 161 has a function of sequentially storing the digital signal values sampled by the sampling unit 160, and is a RAM having a capacity of 2 kbytes, for example.

  FIG. 16 is a flowchart showing a measurement method according to Embodiment 3 of the present invention. The emitted ultrasonic waves in the form of pulses of 20 kHz are output from the ultrasonic transmitter 157 over a period of 50 μsec (step S51). The output time of 50 μs corresponds to one wavelength of 20 kHz ultrasonic waves. This can be realized by sending a transmission command from the control unit 170 to the ultrasonic transmitter 157 during the period. The output time may be for one wavelength, for example, for four wavelengths. The longer the output period, the stronger the energy of the received ultrasonic wave, so that a better result can be obtained. On the other hand, if the output period is shortened to one wavelength, the measurement resolution is improved.

  The sampling unit 160 samples the reflected wave from the target object related to the radiation ultrasonic wave (20 kHz) over a period of 10 milliseconds (step S52).

  Over the sampling period, the ultrasonic receiver 158 receives the ultrasonic wave reflected from the target object, and converts the received ultrasonic wave into an electrical signal. The sampling unit 160 samples the received electrical signal at a sampling interval of 10 μs, converts it into 1024 digital signal values, and outputs the digital signal value. In order to obtain sampling data at an interval of 10 μs, this sampling process takes about 10 milliseconds. The memory 161 sequentially stores 1024 pieces of sampling data. After all the sampling data related to the sampling process is accumulated in the memory 161, a sampling data string including all the sampling data accumulated in the memory 161 is transferred to the distance calculation unit 145.

  The reflection time is calculated based on the sampling data sequence transferred to the distance calculation unit 145, and the distance to the target object is calculated from the result (step S53).

  Here, calculation of the distance to the target object performed by the distance calculation unit 155 will be described. FIG. 17 is a flowchart illustrating a method for calculating the distance to the target object. FIG. 18 is a diagram showing a distance calculation method according to this embodiment. In FIG. 18A, the horizontal axis represents time and the vertical axis represents the received ultrasonic intensity. In this state, since the received reflected wave signal is buried in noise, the reflected wave signal is extracted by FFT processing. A sampling data string composed of 1024 sampling data is obtained from the received ultrasonic intensity value by the sampling unit 160. Further, the observation section composed of the sampling data string is divided into minute sections composed of ten sampling data (step S61). As described above, since the sampling interval is 10 μsec, the length of the minute section is 100 μsec.

When the division into the minute sections is completed, the spectrum intensity of the frequency band to which the frequency of the emitted ultrasound belongs is obtained for the ultrasound received for each minute section. For each minute interval, the number of sampling data included in the sampling data string is increased in order to increase the frequency resolution of the frequency spectrum calculated for the reflected wave received in the minute interval (step S62). FIG. 18B is a diagram showing an increase process of sampling data in the sampling data string. As shown in this figure, for each of the small sections, by arranging repeatedly sampled data sequence D ₀ to D ₉ consisting of ten sampling data, and generates a sampled data sequence consisting of 2048 sampling data. If a sampling data string composed of 2048 sampling data is obtained, FFT is applied to the sampling data string to obtain the spectrum intensity of the frequency band to which the frequency of the emitted ultrasonic wave belongs (step S63). Further, the spectrum intensity is calculated for all minute sections (step S64).

When the spectrum intensity of the frequency band to which the frequency of the radiated ultrasonic wave belongs is obtained for all the minute sections, the time dependency of the spectrum intensity of the frequency band is obtained as shown in FIG. In FIG. 18C, the spectral intensity of the frequency band to which the frequency of the emitted ultrasonic wave belongs is shown for each minute section. That is, the horizontal axis represents time, and the vertical axis represents the spectrum intensity of the 20 kHz band to which the frequency of the emitted ultrasonic wave belongs. Next, a position where the spectrum intensity is maximum, that is, a peak position is obtained (step S65). Since the time corresponding to the peak position is the reception time of the reflected ultrasonic wave, the time T (reflection time) elapsed from when the ultrasonic wave is output until it is reflected and received by the target object is calculated. Is calculated (step S66). The distance R to the target object is given by the following equation (5), where T is the aforementioned T and the sound speed is c.
R = (T / 2) · c (5)

  As described above, the measurement method according to the third embodiment includes a step of outputting a 20 kHz ultrasonic wave in a pulse shape and a step of sampling a reflected wave from a target object related to the 20 kHz ultrasonic wave over a period of about 10 milliseconds. And a reflection time from when the ultrasonic wave of 20 kHz is transmitted until it is reflected by the target object and received based on a sampling data string consisting of 1024 sampled sampling data, and the detected reflection time is And the step of calculating the distance to the target object based on this, it is possible to measure the distance to the target object using a relatively simple technical configuration. In particular, it is possible to accurately measure the distance to the target object positioned obliquely with respect to the measuring apparatus. In particular, it is possible to accurately measure the distance to the target object positioned obliquely with respect to the measuring device.

  Further, the observation section given as a sampling data string composed of the sampled 1024 sampling data is divided into the small sections for each of the ten sampling data, and 10 pieces existing in the small section for each small section. The frequency spectrum of the reflected wave received in the minute section is calculated by applying the fast Fourier transform to the sampling data string consisting of 2048 sampling data obtained by repeatedly arranging the sampling data string consisting of the sampling data of Therefore, the frequency resolution of the frequency spectrum calculated for the reflected wave related to the 20 kHz ultrasonic wave can be increased, and a minute section in which the reflected wave related to the 20 kHz ultrasonic wave is received can be detected with higher accuracy. Because it becomes possible, up to the target object It is possible to reduce the error according to the calculation of the release. Furthermore, the measurement method and apparatus which have tolerance also with respect to mixing of white noise are provided.

In addition, in the apparatus that implements the present embodiment, only one ultrasonic frequency is used, and only the position of the target object is measured. Accordingly, since an ultrasonic transmission element capable of transmitting a predetermined single frequency can be used, a simpler device configuration than that of the first and second embodiments can be adopted, and the measurement speed is also high. It becomes. Furthermore, the method according to this embodiment can be used for most ultrasonic sensor systems.

  Although 20 kHz is used as the frequency of the ultrasonic wave, the frequency of the ultrasonic wave used is not limited to this, and it goes without saying that ultrasonic waves of various frequencies can be used. Further, the period for outputting the ultrasonic waves is not limited to one wavelength, and may be, for example, four wavelengths. The period required for the sampling process is not limited to 10 milliseconds. In the sampling process, the number of data to be sampled is not limited to 1024 each. Further, the number of sampling data existing in the minute section is not limited to ten. The number of data in the sampling data string obtained by increasing the number of sampling data included in the sampling data string composed of 10 sampling data existing in the minute section is not limited to 2048. About the frequency of the ultrasonic wave used, sampling interval, sampling period, the number of sampling data, the number of sampling data existing in a minute section, the increase number of sampling data, etc., the memory used for the measuring device used, It will be understood that the sampling unit, the ultrasonic transmitter, and the ultrasonic receiver can be appropriately changed according to the performance of the device.

  6, 7, 10, 14, 16, and 17, the measurement program comprising the program code for executing the steps described in the flowcharts is a CD-ROM or DVD in which the measurement program is stored. It can be used by obtaining a storage medium such as a ROM, or by downloading from an external server in which the measurement program is stored. A measurement program read from an information storage medium or downloaded from an external server is installed in, for example, a storage unit of a microcomputer, a personal computer, or a dedicated terminal integrated for measurement. The measurement method described in the first to third embodiments can be realized by executing the measurement program installed in the storage unit by, for example, the CPU in the dedicated terminal.

  In addition, the measuring method demonstrated by said Embodiment 1 thru | or 3 does not limit this invention, and is disclosed aiming at illustrating. The technical scope of the present invention is defined by the description of the scope of claims, and various design changes can be made within the technical scope of the invention described in the scope of claims. For example, in the first or second embodiment, the configuration is such that the speed of the target object, the distance to the target object, and the like are measured using two types of ultrasonic waves having a single frequency or different frequencies. It is also possible to measure using two types of electromagnetic waves having different frequencies. For example, one laser beam generator for generating a laser beam with a specific frequency or two laser beam generators for generating laser beams with different frequencies are provided, and a laser beam output using an electronic switch or the like is provided. What is necessary is just to comprise so that it may change suitably. Even in this case, the speed of the target object, the distance to the target object, and the like can be calculated using Equations (1) to (5) in the same manner as when ultrasonic waves are used.

In the measurement method described in the first or second embodiment, the distance to the target object and the number and depth of steps on the surface of the target object are calculated based on the detected one or more reflection times. In this configuration, only the distance to the target object is calculated based on the detected one or more reflection times, or the step on the surface of the target object is calculated based on the detected one or more reflection times. It is also possible to adopt a configuration in which only the number and depth are calculated. It will be understood that all these aspects of the invention are included in the technical scope of the present invention.
Experimental example.

The measurement experiment of the distance and level difference of the inclined arrangement object was performed by the measurement method of the present application. The arrangement of the measuring device 21 and the target object 24 is shown in FIG. The target object 24 includes two flat plates 29 having a width of 15 cm and a height of 60 cm arranged so as to have a step of 2 cm. Measurement was performed by increasing the angle θ between the target object 24 and the measuring device 21. The frequency of the emitted ultrasonic wave was 20 kHz. The distance Z between the measuring device 21 and the target object 24 was changed in five steps within a range of 50 cm to 150 cm.
The measuring apparatus has the configuration shown in FIG. The speaker 107 corresponding to the ultrasonic transmission unit uses an acoustic speaker FOSTEX FT17H, and the microphone 108 corresponding to the ultrasonic reception unit uses an acoustic microphone AV LEADER PHM903.

  According to the method of Embodiment 1 or 2 (dual frequency type) of the present invention, “maximum object inclination angle θ1 at which the object surface step can be accurately measured” and “object surface step cannot be measured for each distance Z. The maximum object inclination angle θ2 ”that can accurately measure the existence distance of the object was measured. In the measurement of θ1, the inclination angle of the object is increased in units of 1 ° at each measurement apparatus-target object distance, measurement is performed 10 times at each inclination angle, and it is determined that the object surface step can be read from all 10 results. The maximum object tilt angle was set. The criterion for “reading the object surface step” is that two peaks from the step are clearly seen in the spectrum intensity of the emitted ultrasonic wave at 20 KHz, and the distance between each peak matches the actual depth of the step. It was decided. Further, “the object surface step cannot be read” is a case where only one peak is clearly detected but the other peaks are not clear or only one peak can be detected. In this case, it becomes the measurement object of θ2, and “the object existing distance can be measured accurately” means that the S / N ratio of the peak of the same frequency spectrum intensity as the frequency of the transmitter is 2 or more, and the peak distance value is actually The distance value of the measured object was the same. FIGS. 20A and 20B show θ1 and θ2 with respect to the distance Z, respectively. In FIG. 20 and FIG. 21 to be described later, the horizontal axis represents the distance Z in cm, and the vertical axis represents θ1 or θ2 in degrees.

Further, in the method of Embodiment 3 (single frequency type) of the present invention and the conventional measurement method, the step cannot be measured, but the distance to the target object can be measured. The maximum object inclination angle that can be measured is measured as θ2. Also in this case, the case where the S / N ratio was 2 or more was determined as “distance measurement possible”. FIG. 21 shows a comparison of θ2 by measurement of the two-frequency type, the one-frequency type, and the conventional type. The conventional type is a distance measurement method in which an ultrasonic pulse radiated from a transmitter is received by a receiver, the intensity of the reflected wave is measured, and the reflection time is obtained from the peak position of the reflected wave intensity. In the conventional measurement, the apparatus configuration is the same as that shown in FIG. 3, and a part of the processing flow of Embodiment 1 of the present invention is used. In FIG. 21, B is a measurement by a two-frequency type, A is a measurement by a one-frequency type, and C is a measurement value by a conventional type. FIG. 21 shows that the distance can be measured even with a large inclination angle compared to the conventional type in both the two-frequency type and the one-frequency type. Therefore, the method of the present invention is effective as a distance measuring method for an object positioned obliquely. In particular, the two-frequency type can read the step even if the target object is tilted.

Application to parking support for cars.
The measuring method according to the present invention can detect the distance to the wall and, in some cases, the relative speed and level difference, and in particular, can accurately measure even when the wall is oblique to the measuring device. Can be used. Further, by attaching the measuring device according to the present invention to the body of an automobile, it is possible to facilitate the garage of the automobile. The attachment positions are attached to the left and right ends or the front and rear ends of both ends. That is, (1) left front end and left rear end, (2) right front end and right rear end, (3) left front end, left rear end, right front end and right rear end may be used. Moreover, it is preferable to attach the measuring device 21 to the vehicle body so that the ultrasonic waves emitted from the ultrasonic transmission unit 22 such as the speaker 197 and the ultrasonic transmitter 157 are radiated perpendicularly to the left and right side surfaces of the vehicle body. This is because the distance from the wall surface arranged parallel to the longitudinal direction of the vehicle body can be measured with high accuracy.

  The following procedures are used to store a garage by the measurement method according to the present invention and to store a garage of an automobile having the measuring device according to the present invention attached to the vehicle body. FIG. 22 shows a situation where the automobile 210 to which the measuring apparatus 100 shown in FIG. 3 is attached enters the garage 220 while backing up. Since there is a wall 225 along the road 205, the measuring apparatus is used. It is possible to enter the garage by detecting the position of the wall. The wall 225 has a step 230 made of a depression recessed at a right angle at the entrance of the garage 220. This embodiment shows a device attached to the left side of the vehicle body to turn left into the garage while backing, and has a device 241 attached to the front end of the vehicle body 204 and a device 242 attached to the rear end. And Furthermore, in this example, substantially only the device 242 attached to the rear end is used for garage storage, so the device 241 attached to the front end is not necessary. The devices 241 and 242 are preferably attached to the vehicle body so that the ultrasonic radiation direction 249 emitted from the ultrasonic transmission unit is emitted perpendicularly to the left and right side surfaces of the vehicle body.

  The automobile 210 moves in the order of (1) → (2) → (3) → (4) in FIG. FIG. 23 shows the detection result by the device, where (a) corresponds to the device 241 and (b) corresponds to the device 242. Further, (1) to (4) correspond to the positions (1) to (4) of the automobile in FIG. In each graph shown in FIG. 23, the horizontal axis represents time, and the vertical axis represents the spectrum intensity of the frequency band to which the frequency of the emitted ultrasonic wave belongs. FIG. 24 is a flowchart showing a procedure for entering a garage. At the start of entering the garage, the car starts moving straight back (step S81), and starts measuring the distance to the wall (step S82). Measurement will continue until parking is completed. At the position (1), since the two devices 241 and 242 both detect the flat wall 230, only one surface is detected. This is (1) and (b) in FIG. When the automobile backs and reaches the position (2), the rear measuring device 242 detects the step 230 (step S83). That is, two surfaces are detected due to the presence of the step 230. This is (2) and (b) in FIG. At this point, the steering wheel is turned off (step S84), and the car turns while turning. In the process, an oblique state (3) is obtained. At this time, a state in which the step is not detected occurs due to the angle relationship between the step 230 and the measurement layer value 242 behind. This corresponds to the state of detecting only one surface shown in (3) and (b) of FIG. In addition, the car turns back while turning. Thereafter, the automobile changes its direction by 90 ° from the initial state, and the rear of the vehicle body enters a garage (4). At this time, the device 242 again detects two surfaces by the step 230 (step S85). ). This corresponds to (4) and (b) of FIG. At this time, the steering wheel is returned (step S86), and then the vehicle travels straight forward, stops at a predetermined position, ends the measurement by the apparatus (step S87), and finally completes garage entry. In this way, by detecting the two surfaces with the devices 241 and 242 attached to the end portions of the vehicle body → detecting the one surface → detecting the two surfaces and corresponding to the operation of the steering wheel, it is easy to put the car into the garage. It is possible to proceed safely.

  The invention of the present application is a sensor for acquiring information such as speed information, distance information, and surface shape information relating to an object moving in the surrounding environment, such as an external sensor for an autonomous mobile robot, an inter-vehicle information sensor for an automobile, and an automobile auto It can be widely applied to sonar systems in parking systems, sensors on production lines, security sensors, and the like.

Claims (29)

Continuously outputting ultrasonic waves of a first frequency over a predetermined period;
Sampling a reflected wave from a target object related to an ultrasonic wave of a first frequency;
Calculating a relative velocity of the target object based on the sampled first sampling data sequence;
Outputting ultrasonic waves of the second frequency in a pulsed manner after continuously outputting ultrasonic waves of the first frequency over a predetermined period; and
Sampling reflected waves from a target object related to ultrasonic waves of a first frequency and ultrasonic waves of a second frequency;
Detecting one or a plurality of reflection times from when the ultrasonic wave of the second frequency is transmitted based on the sampled second sampling data string until it is reflected by the target object and received;
And a step of calculating the distance to the target object or the number and depth of steps on the surface of the target object based on the detected one or more reflection times. Continuously outputting ultrasonic waves of a first frequency over a predetermined period;
Outputting ultrasonic waves of the second frequency in a pulsed manner after continuously outputting ultrasonic waves of the first frequency over a predetermined period; and
Sampling reflected waves from a target object related to ultrasonic waves of a first frequency and ultrasonic waves of a second frequency;
Calculating a relative velocity of the target object based on the sampled sampling data sequence;
Detecting one or more reflection times from when the ultrasonic wave of the second frequency is transmitted based on the sampled sampling data sequence until it is reflected by the target object and received;
And a step of calculating the distance to the target object or the number and depth of steps on the surface of the target object based on the detected one or more reflection times. The measurement method according to claim 1 or 2, wherein an ultrasonic wave having a second frequency is output for approximately one wavelength. A section composed of the entire sampling data included in the sampling data sequence sampled to detect one or a plurality of reflection times from when the ultrasonic wave of the second frequency is transmitted until it is reflected by the target object and received. The measurement method according to claim 1 or 2, wherein the measurement is divided into minute sections, and the length of each minute section is made equal to approximately one wavelength of the ultrasonic wave of the second frequency. 3. The measurement method according to claim 1, wherein the distance to the target object or the depth of the step on the surface of the target object is corrected using the relative speed of the target object. By applying a fast Fourier transform to a sampling data string obtained by arranging a plurality of zeros after a sampling data string sampled in order to calculate the relative velocity of the target object, ultrasonic waves of the first frequency are applied. The measurement method according to claim 1, wherein a frequency spectrum of a reflected wave from the target object is calculated. A fast Fourier transform is applied after a window function is applied to a sampling data sequence obtained by arranging a plurality of zeros after the sampled sampling data sequence to calculate the relative velocity of the target object. The measuring method according to claim 6. A section composed of the entire sampling data included in the sampling data sequence sampled to detect one or a plurality of reflection times from when the ultrasonic wave of the second frequency is transmitted until it is reflected by the target object and received. By applying a fast Fourier transform to the sampling data sequence obtained by repeatedly arranging the sampling data sequence composed of the sampling data existing in the minute interval for each minute interval. The measurement method according to claim 1, wherein the frequency spectrum of the reflected wave received in the section is calculated. 9. The measurement method according to claim 8, wherein a fast Fourier transform is applied after a window function is applied to a sampling data string obtained by repeatedly arranging sampling data strings composed of sampling data existing in a minute section. . Continuously outputting ultrasonic waves of a first frequency over a predetermined period;
Sampling a reflected wave from a target object related to ultrasonic waves of a first frequency;
Calculating a relative velocity of the target object based on the sampled first sampling data string;
Outputting ultrasonic waves of the second frequency in a pulsed manner after continuously outputting ultrasonic waves of the first frequency over a predetermined period;
Sampling reflected waves from a target object related to ultrasonic waves of a first frequency and ultrasonic waves of a second frequency;
Detecting one or a plurality of reflection times from when the ultrasonic wave of the second frequency is transmitted based on the sampled second sampling data string until it is reflected by the target object and received;
And a step of calculating the distance to the target object or the number and depth of steps on the surface of the target object based on the detected one or more reflection times. Continuously outputting ultrasonic waves of a first frequency over a predetermined period;
Outputting ultrasonic waves of the second frequency in a pulsed manner after continuously outputting ultrasonic waves of the first frequency over a predetermined period;
Sampling reflected waves from a target object related to ultrasonic waves of a first frequency and ultrasonic waves of a second frequency;
Calculating a relative velocity of the target object based on the sampled sampling data sequence;
Detecting one or a plurality of reflection times from when the ultrasonic wave of the second frequency is transmitted based on the sampled sampling data sequence until it is reflected by the target object and received;
And a step of calculating the distance to the target object or the number and depth of steps on the surface of the target object based on the detected one or more reflection times. Continuously outputting an electromagnetic wave having a first frequency over a predetermined period;
Sampling a reflected wave from a target object related to an electromagnetic wave of a first frequency;
Calculating a relative velocity of the target object based on the sampled first sampling data sequence;
Outputting the electromagnetic wave of the second frequency in a pulsed manner after continuously outputting the electromagnetic wave of the first frequency over a predetermined period;
Sampling a reflected wave from a target object related to an electromagnetic wave of a first frequency and an electromagnetic wave of a second frequency;
Detecting one or a plurality of reflection times from when the electromagnetic wave of the second frequency is transmitted based on the sampled second sampling data string until it is reflected by the target object and received;
And a step of calculating the distance to the target object or the number and depth of steps on the surface of the target object based on the detected one or more reflection times. Continuously outputting an electromagnetic wave having a first frequency over a predetermined period;
Outputting the electromagnetic wave of the second frequency in a pulsed manner after continuously outputting the electromagnetic wave of the first frequency over a predetermined period;
Sampling a reflected wave from a target object related to an electromagnetic wave of a first frequency and an electromagnetic wave of a second frequency;
Calculating a relative velocity of the target object based on the sampled sampling data sequence;
Detecting one or more reflection times from when the electromagnetic wave of the second frequency is transmitted based on the sampled sampling data sequence until it is reflected by the target object and received;
And a step of calculating the distance to the target object or the number and depth of steps on the surface of the target object based on the detected one or more reflection times. Outputting ultrasonic waves of a predetermined frequency in a pulse form;
Sampling a reflected wave from a target object related to the ultrasonic wave of the predetermined frequency;
Based on the sampled sampling data string, the reflection time from when the ultrasonic wave of the predetermined frequency is transmitted until it is reflected and received by the target object is detected, and based on the detected reflection time, the target object is detected. And a step of calculating the distance. The measurement method according to claim 14, wherein the ultrasonic wave having the predetermined frequency is output for approximately one wavelength. A section made up of the entire sampling data included in the sampling data sequence sampled to detect the reflection time from when the ultrasonic wave of the predetermined frequency is transmitted until it is reflected by the target object and received is divided into minute sections. Then, by applying a fast Fourier transform to the sampling data sequence obtained by repeatedly arranging the sampling data sequence composed of the sampling data existing in the minute interval for each minute interval, the signal is received in the minute interval. The measurement method according to claim 14, wherein the spectrum intensity of a frequency band to which the predetermined frequency of the reflected wave belongs is calculated. Outputting ultrasonic waves of a predetermined frequency in a pulse form;
Sampling a reflected wave from a target object related to the ultrasonic wave of the predetermined frequency;
Based on the sampled sampling data string, the reflection time from when the ultrasonic wave of the predetermined frequency is transmitted until it is reflected and received by the target object is detected, and based on the detected reflection time, the target object is detected. And a step of calculating the distance. A first ultrasonic transmission unit that continuously outputs ultrasonic waves of a first frequency over a predetermined period;
A second ultrasonic transmission unit that outputs ultrasonic waves of the second frequency in a pulsed manner;
A receiving unit for ultrasonic waves transmitted from the first and second ultrasonic transmitting units;
A sampling unit that samples the reflected wave from the target object related to the received ultrasonic waves of the first and second frequencies;
A relative velocity calculation unit that calculates a relative velocity of the target object based on a sampling data string related to the sampled ultrasonic waves of the first frequency;
Reflection for detecting one or a plurality of reflection times from when the ultrasonic wave of the second frequency is transmitted to the target object after being received based on the sampled data sequence related to the sampled ultrasonic wave of the second frequency A time calculator,
A distance and step calculation unit that calculates a distance to the target object or the number and depth of steps on the surface of the target object based on the detected one or more reflection times; apparatus. The measuring apparatus according to claim 18, wherein the second ultrasonic wave transmitting unit outputs ultrasonic waves of the second frequency for approximately one wavelength. The distance and step calculation unit corrects the distance to the target object or the depth of the step on the surface of the target object using the relative speed calculated by the relative speed calculation unit. The measuring device described. A fast Fourier transform processing unit that performs a fast Fourier transform processing on a sampling data string from the target object related to the ultrasonic waves of the first or second frequency, and the result of the fast Fourier transform processing unit is the relative velocity calculation unit or The measurement apparatus according to claim 18, wherein the measurement apparatus is used for processing in the processing in the distance and level difference calculation unit. A window function processing unit for applying a window function to the sampling data string from the target object related to the ultrasonic wave of the first or second frequency, and the output result of the window function processing unit is converted into the fast Fourier transform process. The measurement apparatus according to claim 21, wherein the measurement apparatus inputs the signal to the unit. An ultrasonic transmission unit that outputs ultrasonic waves of a specific frequency in a pulse form;
An ultrasonic receiving unit transmitted from the ultrasonic transmitting unit;
A sampling unit that samples a reflected wave from a target object related to the received ultrasonic wave of the specific frequency;
Based on the sampling data string relating to the sampled ultrasonic waves of the specific frequency, the reflection time from the transmission of the ultrasonic waves of the frequency to the reception of the target object is detected, and the detected reflection time is detected. And a distance calculating unit that calculates a distance to the target object. The measurement apparatus according to claim 23, wherein the ultrasonic wave transmission unit outputs ultrasonic waves of the specific frequency for approximately one wavelength. A fast Fourier transform processing unit that performs fast Fourier transform processing on a sampling data sequence from the target object related to the ultrasonic wave of the specific frequency, and uses a result of the fast Fourier transform processing unit for processing in the distance calculation unit; 24. The measuring apparatus according to claim 23.   An automobile having a vehicle body and the measurement device according to claim 18, wherein the measurement device is attached to a front end and a rear end of a left side surface and / or a right side surface of the vehicle body.   An automobile having a vehicle body and the measurement device according to claim 23, wherein the measurement device is attached to a front end and a rear end of a left side surface and / or a right side surface of the vehicle body.   28. The automobile according to claim 26 or 27, wherein the measuring device is mounted so that an ultrasonic radiation direction of the measuring device is perpendicular to the left side surface or the right side surface. A method of putting a car according to claim 26 into a garage having a wall surface having a step near the entrance,
The distance and level difference to the wall surface are continuously measured by the measuring device of the automobile, and the handle is operated when the level changes from the state where the level difference is not detected to the level where the level difference is detected. How to garage.

Images