JP2003214833A - Distance measuring device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a distance measuring device using ultrasonic wave whose measuring range is not limited. <P>SOLUTION: The distance measuring device that measures a distance to an object by using ultrasonic wave, is provided with a preset distance range storage means 2 that stores a plurality of preset distance ranges, and a sending condition storage means 3 that stores a condition of sending ultrasonic wave according to the preset distance ranges. Thus, the energy of ultrasonic wave in an ultrasonic wave sending part 4 is made small to reduce a direct wave of the ultrasonic wave, permitting short-distance measurement, and furthermore, the energy of ultrasonic therein is made large so that long-distance measurement is made possible. Therefore, such a distance measuring device whose measuring range is not limited can be obtained. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a distance measuring device for measuring a distance to an object to be measured in a non-contact manner using ultrasonic waves.

[0002]

2. Description of the Related Art A conventional technique will be described with reference to FIGS.

First, the configuration of the prior art will be described with reference to FIG.

In FIG. 11, reference numeral 14 is a distance measurement starting means, which outputs a distance measurement start signal when starting the distance measurement.

When the distance measurement start signal from the distance measurement start means 14 is input, the transmission signal output means 15 transmits a signal of a specific frequency to the ultrasonic transmission sensor 16.

Reference numeral 16 denotes an ultrasonic wave transmission sensor, which transmits an ultrasonic wave to a measuring object whose distance is to be measured by inputting a signal of a specific frequency by the transmission signal output means 15.

Reference numeral 17 denotes an ultrasonic wave reception sensor, which receives the reflected wave of the ultrasonic measurement object sent from the ultrasonic wave transmission sensor 16 and outputs a reception signal.

The distance measuring means 18 is the distance measuring starting means 1
The distance measurement start signal of 4 and the reception signal of the ultrasonic receiving sensor 17 are input, the distance from the distance measurement start signal and the reception signal to the measurement object is calculated, and the distance output is output.

Next, the operation will be described with reference to FIG.

FIG. 2 is a diagram showing an ultrasonic wave transmitted by the ultrasonic wave transmitting sensor 16, a direct wave, and a reflected wave by the ultrasonic wave receiving sensor 17. However, the horizontal axis is time and the vertical axis is the amplitude of the waveform.

As shown in FIG. 2, the ultrasonic transmission sensor 16
There is a time lag Δt between the transmitted wave of the ultrasonic wave and the reflected wave of the ultrasonic wave reception sensor 17. This indicates that it takes time Δt before the ultrasonic wave transmitted from the ultrasonic wave transmission sensor 16 is reflected on the measurement object and returned to the ultrasonic wave reception sensor 17. This time difference Δt can be expressed as Δt = (L1 + L2) / V.

However, the distance L1 (cm) from the ultrasonic transmission sensor 16 to the measuring object, the distance L2 (cm) from the measuring object to the ultrasonic receiving sensor 17, and the ultrasonic velocity V (cm / msec). ).

If the ultrasonic transmission sensor 16 and the ultrasonic reception sensor 17 are installed at almost the same place, the distance L between the distance measuring device and the object to be measured is L = L1 = L2. Can be expressed as

L (cm) = 17 (cm / msec) × Δt It was calculated assuming that the ultrasonic velocity V was 34 (cm / msec).

That is, the ultrasonic wave transmission time t1 of the ultrasonic wave transmission sensor 16 and the reception time t2 of the reflected wave of the ultrasonic wave reception sensor 17 are measured, and the time difference Δt is calculated to obtain the ultrasonic wave transmission sensor 16 and the ultrasonic wave reception. The distance between the distance measuring device in which the sensor 17 is installed and the measuring object can be measured.

Direct waves are also shown in FIG. The direct wave means the ultrasonic wave transmitting sensor 16 to the ultrasonic wave receiving sensor 1
7 is an ultrasonic waveform directly transmitted to a printed circuit board, a housing, etc., and its time and amplitude are determined by the transmission time of the transmission wave, transmission energy, and the like.

The distance measuring means 18 is the distance measuring starting means 1
The distance is measured by measuring the times t1 and t2 when the distance measurement start signal of 4 and the reception signal of the ultrasonic receiving sensor 17 are input, and obtaining the time difference Δt.

[0018]

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention
According to the operation, by measuring the transmission time t1 and the reception time t2 of the ultrasonic waves and calculating the time difference Δt between them, the distance L between the distance measuring device and the measurement object can be measured.

However, since the energy when the ultrasonic wave propagates decreases in inverse proportion to the distance, when the energy of the transmitted wave of the ultrasonic wave transmission sensor 16 is small, the object to be measured becomes far, or the object to be measured is reflected. The distance cannot be measured when the material is difficult to perform, or when the direction of the ultrasonic transmission sensor 16 is not toward the measurement object.

Therefore, in general, when measuring a distance by ultrasonic waves, it is possible to measure medium and long distances or to measure even when the object to be measured is difficult to reflect.
An ultrasonic wave with large energy is transmitted.

However, by increasing the energy of the transmission wave transmitted from the ultrasonic transmission sensor 16, the energy of the direct wave from the ultrasonic transmission sensor 16 to the ultrasonic reception sensor 17 also increases.

Therefore, when the distance to the object to be measured is short, the direct wave and the reflected wave cannot be distinguished, so that the distance between the distance measuring device and the object to be measured cannot be accurately measured.

That is, according to the configuration and operation of the above-mentioned prior art, the ultrasonic measurement range is determined by the ultrasonic transmission energy of the ultrasonic transmission sensor 16. If the transmission energy is large, the distance to the object to be measured is short. If the energy cannot be measured accurately and conversely the energy is small, the distance to the measurement object is long, or the measurement object is a material that is difficult to reflect, or the orientation of the ultrasonic transmission sensor 16 is the measurement object. It is not possible to measure the distance to the object to be measured, such as when not facing the object.

As described above, the conventional technique has a problem that the measurement range of the distance measuring device using ultrasonic waves is limited.

The present invention solves the above-mentioned conventional problems, and an object of the present invention is to provide a distance measuring device using ultrasonic waves, which does not limit the measuring range.

[0026]

SUMMARY OF THE INVENTION In order to solve the above problems, the present invention provides a method for measuring the distance to an object to be measured by ultrasonic waves according to the state of the distance measuring device or the state of the object to be measured. The distance measuring device was used to change the conditions for transmitting sound waves.

As a result, first, by transmitting a small amount of energy of the ultrasonic wave transmitting sensor, the direct wave of the ultrasonic wave is reduced to enable the short distance measurement. The energy of the ultrasonic wave transmission sensor is large, and the reflected wave of the ultrasonic wave is increased by sending out the ultrasonic wave. When the distance of the measuring object is long, the distance when the measuring object is a material that is difficult to reflect, etc. It enables measurement.

Therefore, the measurement range is limited by changing the transmission energy of the ultrasonic wave by the ultrasonic wave transmission sensor (ultrasonic wave transmission section) according to the state of the measuring object and the state of the distance measuring device. It is possible to provide a distance measuring device using ultrasonic waves.

The present invention is more effective when it has only one ultrasonic wave transmission sensor (ultrasonic wave transmission section).

[0030]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The invention according to claim 1 sets an ultrasonic wave transmission condition according to the state of a distance measuring device for measuring the distance to an object to be measured by ultrasonic waves or the state of the object to be measured. The distance measuring device was changed.

Thus, for example, first, by transmitting an ultrasonic wave having a small energy, the direct wave of the ultrasonic wave is reduced and a short distance can be measured.
Next, by transmitting ultrasonic waves with large energy, the reflected wave of ultrasonic waves is increased, so that distance measurement can be performed when the distance to the measurement target is long or when the measurement target is a material that is difficult to reflect. It is what Therefore, depending on the state of the measuring object, the state of the distance measuring device,
By changing the ultrasonic wave transmission energy by the ultrasonic wave transmission sensor, the distance of the measurement object can be measured in any case.

According to the second aspect of the present invention, the distance measuring device for measuring the distance to the measuring object by ultrasonic waves and the distance measuring device for changing the ultrasonic wave sending conditions according to the distance between the measuring object. And

Accordingly, when the target distance is long, the ultrasonic wave transmission energy is increased, and when the target distance is short, the ultrasonic wave transmission energy is decreased, so that the distance to the object to be measured can be increased at any distance. Can be measured. Further, since the pinpoint distance measurement for measuring whether or not the measurement object exists at the set distance is performed, the distance range of the measurement object can be measured, the distances of a plurality of measurement objects can be simultaneously measured, and the like. .

According to a third aspect of the present invention, there are provided set distance range storage means for storing a plurality of set distance ranges, and sending condition storage means for storing ultrasonic wave sending conditions according to the plurality of set distance ranges. The distance measuring device is provided which measures the distance to the object to be measured by ultrasonic waves.

As a result, the optimum conditions for sending to the ultrasonic wave sending unit in the set range are stored, and the distance is measured by ultrasonic waves under that condition, so that the distance can be measured more easily over a wider range.

According to a fourth aspect of the present invention, in addition to the invention according to the first or second aspect, a set distance range storage means for storing a plurality of set distance ranges and a super unit corresponding to the plurality of set distance ranges are provided. A distance measuring device is provided, which is provided with a sending condition storage unit that stores sending conditions of sound waves, and that measures a distance to an object to be measured by ultrasonic waves.

Thus, in addition to the effect of the first or second aspect, the optimum sending condition to the ultrasonic sending unit for the set range is stored and the distance measurement by the ultrasonic wave is performed under the condition.
Distance measurement can be performed more easily in a wider range.

According to a fifth aspect of the present invention, in addition to the third or fourth aspect of the present invention, distance control means is provided, and the set distance range storage means receives the distance control signal from the distance control means. As a result, a distance measuring device for starting the output in the set distance range is provided.

As a result, since the distance measurement starts after the distance control signal is input, the set distance range currently being measured can be accurately known by checking the time from the distance control signal, so that more accurate distance measurement can be performed. It can be carried out.

According to a sixth aspect of the present invention, in addition to the fifth aspect of the invention, when the distance of the object to be measured can be measured, the set distance range storage means stops the output of the set distance range. The measuring device was used.

Therefore, when the distance measurement is completed, the distance measurement is stopped, so that no time is wasted, and the distance measurement can be speeded up.

According to a seventh aspect of the present invention, in addition to the fifth or sixth aspect of the present invention, a distance measurement time storage means for storing distance measurement time is provided, and the distance control means has an interval of the distance measurement time. The distance measurement device outputs a distance control signal.

Since the distance measurement is performed at intervals of the distance measurement time stored in the distance measurement time storage means, the latest distance information can always be collected.

The invention described in claim 8 is particularly characterized by claim 7.
In the distance measuring device, the distance measuring time stored in the distance measuring time storing means described in 1 is equal to or longer than the minimum time determined by the set distance range stored in the set distance range storing means.

Therefore, although the distance can be actually measured by setting the minimum time for the distance measurement time,
Since the distance measurement time starts shortly after the next distance measurement cycle starts and the distance measurement cannot be stopped, the reliability of the distance measurement result can be further improved.

The invention described in claim 9 is particularly characterized by claim 7.
Alternatively, if the distance control means described in 8 cannot measure the distance at the distance measurement time interval stored in the distance measurement time storage means, the distance to the measurement object is set to be stored in the set distance range storage means. The distance measuring device was determined to be within the distance range.

Therefore, by determining that the object to be measured is within the set distance range, it is possible to speed up the measurement time without wasting time during the distance measurement.

According to the tenth aspect of the present invention, in particular, the sending condition storage means according to any one of the third to ninth aspects,
When the set distance range is short, the distance measuring device is used to shorten the ultrasonic wave transmission time.

Therefore, the distance can be accurately measured even when the set distance is short by reducing the ultrasonic wave transmission energy. Further, since shortening the sending time can be realized with a simple configuration, it is possible to more easily perform distance measurement in a wide range.

According to an eleventh aspect of the present invention, the transmission condition storage means according to any one of the third to tenth aspects stores the frequency of the ultrasonic wave and responds to the set distance range by the set distance range storage means. The distance measuring device outputs the frequency of ultrasonic waves.

Therefore, by changing the frequency of the ultrasonic wave in accordance with the setting range, even if a large number of reflected waves of the ultrasonic wave are returned to the ultrasonic wave receiving sensor at one time, which frequency range is in the setting range? By checking, it is possible to measure the distance of the measuring object more accurately without erroneous detection.

[0052]

Embodiments of the present invention will be described below with reference to the drawings.

(Embodiment 1) FIG. 1 is a block diagram showing the configuration of a distance measuring device according to a first embodiment of the present invention. In FIG. 1, 1 is a distance control means, which outputs a distance control signal to the set distance range storage means 2 at a time interval T stored in the control interval storage means 8 when a distance measurement command is given, and starts distance measurement. . The set distance range storage means 2 stores set distance ranges for distance measurement by a plurality of ultrasonic waves, and when the distance control signal of the distance control means 1 is input, the set distance ranges are generally sent in order from a short distance. Output to the means 3. The sending condition storage means 3 stores sending conditions to the ultrasonic wave transmitting unit 4 corresponding to the set distance range,
When the set distance range stored in the set distance range storage means 2 is input, the transmission condition signal is output to the ultrasonic wave transmission unit 4.

The ultrasonic wave transmission unit 4 changes the state of the ultrasonic wave transmission sensor according to the transmission condition signal stored in the transmission condition storage means 3 and irradiates the measurement object with ultrasonic waves. The ultrasonic wave reception unit 5 receives the reflected wave of the ultrasonic wave to the measurement object from the ultrasonic wave transmission unit 4, detects the waveform, and outputs it as an ultrasonic wave reception signal.

The distance calculating means 6 receives the sending condition signal of the sending condition storing means 3 and the ultrasonic receiving signal of the ultrasonic receiving section, and the time interval Δ between the sending condition signal and the ultrasonic receiving signal.
The distance L from t to the object to be measured is calculated by the following formula and output as a distance output.

L (cm) = 17 (cm / msec) × Δ
t (msec) Further, the distance calculation means 6 also receives the control interval T of the control interval storage means 8 from the time when the sending condition is input until the time when the next distance control signal is output becomes the control interval T or more. If the ultrasonic reception signal is not input, it is assumed that the distance to the measurement object is the maximum set distance Lmax or more.

Reference numeral 7 denotes a distance measurement stopping means, which determines that the distance has been determined when the distance output L is output by the distance calculating means 6, and outputs a set distance range stop signal to the set distance range storage means 2.
Then, the output of the set distance range of the set distance range storage means 2 is stopped.

Next, the operation of this embodiment will be described.

First, transmission waves, reception waves, and direct waves of ultrasonic waves will be described with reference to FIG. FIG. 2 is a diagram showing a time chart of ultrasonic transmission waves, reception waves, and reflected waves. However, the vertical axis represents the ultrasonic wave amplitudes A1 and A2, and the horizontal axis represents the time t.

As shown in FIG. 2, an ultrasonic wave which generally belongs to an ultrasonic wave region of about 40 kHz is transmitted from the ultrasonic wave transmitter 4 to the object to be measured. The reflected wave of the ultrasonic wave reflected from the measuring object is received by the ultrasonic wave receiving unit 5 after a time difference Δt from the transmission wave being transmitted. Further, since the ultrasonic wave transmitting unit 4 and the ultrasonic wave receiving unit 5 are set in the same distance measuring device, the transmitted wave becomes a direct wave of time Δt1 via the body of the distance measuring device and the printed circuit board, and the ultrasonic wave is received. Propagate to part 5.

Next, the principle of distance measurement by the ultrasonic measuring device will be described.

When the distance from the ultrasonic wave receiving unit 4 to the measuring object is L1 and the distance to the measuring object is L2, Δt = (L1 + L2) / V can be calculated. However, V is the velocity of the sound wave, and V is approximately 34 (cm / msec). If the setting positions of the ultrasonic wave transmitting unit 4 and the ultrasonic wave receiving unit 5 are the same, then L = L1 = L2, so the above equation is L (cm) = 17 (cm / msec) × Δt (msec) It can be transformed into (1) and the time difference Δt measured by the equation (1)
By substituting
Can be asked.

Next, the direct wave of ultrasonic waves will be described.

It has been empirically known that the energy of the direct wave of the ultrasonic wave in FIG. 2 generally increases in proportion to the energy of the transmitted wave. Also,
Even if the reflected wave is received in the time zone in which the direct wave of the ultrasonic wave exists, the direct wave and the reflected wave cannot be distinguished. Therefore, it can be understood that the ultrasonic measurement device of FIG. 2 has a dead zone time in which the distance cannot be measured until the time Δt1 when the direct wave disappears after the transmission wave of the ultrasonic wave is transmitted.

Next, the reflected waves of ultrasonic waves will be described.

The energy E of ultrasonic waves is attenuated while propagating in air, and the energy E of ultrasonic waves is generally the propagation distance r.
Can be expressed by the following equation.

E ∝ 1 / r ^ 2 That is, the longer the distance L to the object to be measured,
It can be seen that the energy of the reflected wave of the ultrasonic wave receiver 4 decreases in inverse proportion to the square of the distance.

From the relationship among the transmitted wave of ultrasonic waves, the direct wave, and the reflected wave described above, when the distance L to the object to be measured is short, in order to shorten the dead zone region Δt1 due to the direct wave,
It can be seen that the energy of the transmitted wave must be reduced. On the contrary, when the distance L to the measurement target is long, it is understood that the energy of the transmitted wave must be increased in order to increase the energy of the reflected wave.

Next, the operation of the set distance range storage means 3 and the transmission condition storage means 4 will be described with reference to FIG. Figure 3
FIG. 4 is a diagram showing a time chart of a transmitted wave, a received wave, and a reflected wave of ultrasonic waves. However, the vertical axis represents the ultrasonic amplitude A.
1, A2, and the horizontal axis represents time t. FIG. 3 illustrates the method used in this example to extend the range of the distance measuring device.

First, the first transmission wave having a small transmission wave energy is transmitted in order to measure the range in which the distance to the measurement object is short, and after time T1, the transmission wave energy is large in order to measure the range in which the distance is long. The second transmission wave is transmitted. That is, the first transmission wave measures the first distance time T1 from the distance range x1 to x2, and the second transmission wave measures the second distance measurement time T2 from the distance range x3 to x4. However, x1 <x2 and x3 <x4.

As shown in FIG. 3, the first set distance time T
Since the second reflected wave does not return within 1, it is determined that the distance to the measurement object is the set distance x2 or more. After that, the second transmission wave is transmitted, and the reception wave returns with the time difference Δt within the second set distance time T2, and thereby the distance L to the measurement object is calculated from the formula (1), thereby measuring the measurement object. The distance to can be measured. However, x3 <L <x4.

Therefore, the distance measuring device of the system shown in FIG.
Measuring range x1 to x2 or measuring range x3 to x4
The distance from the measurement range x1 to x4 can be measured, as compared with the case where there is only one transmitted wave. Therefore, by changing the transmission wave energy and transmitting a plurality of transmission waves, the measurement range of the distance measuring device can be dramatically expanded.

When the example of FIG. 3 is shown as an example, the set distance range storage means 2 stores the set distance range x1 to x2 or the set distance range x3 to x4, and the distance control signal from the distance control means 1 is received. When input, the set distance range x1 to x2 is first output, and then the set distance range x3 to x4 is output to the sending condition storage means 3.

When the set distance range x1 to x2 by the set distance range storage means 2 is input, the transmission condition storage means 3 ultrasonically transmits the transmission conditions of the first transmission wave, for example, the transmission time and the amplitude of the transmission wave. Output to section 4. Further, if the set distance / distance range set by the set distance range storage means 3 is x3 to x4, the transmission wave condition storage unit 3 similarly outputs the transmission condition of the second transmission wave to the ultrasonic transmission unit 4. further,
The distance calculation unit 6 measures the time Δt until the reception wave is input to the ultrasonic wave reception unit 5 by using the time when the transmission condition is output by the transmission wave condition storage unit 3 as a trigger, and (1)
The distance is calculated by substituting it into the formula and the distance is output.

When the distance calculation means 6 outputs the distance, the distance measurement stop means 7 outputs a distance measurement stop signal to the set distance range storage means 2 on the assumption that the distance of the object to be measured can be measured. , Stop transmitting ultrasonic waves. In the above description, as a method of changing the transmitted wave energy,
Although the amplitude and the transmission time of the transmitted wave are described, the simplest method is to change the transmitted time of the transmitted wave, and this method does not require a complicated configuration change of the ultrasonic transmission unit 4, so it can be easily realized. it can.

Further, by changing the transmission frequency between the first transmission wave and the second transmission wave, it is possible to distinguish the reflected wave by the first transmission wave and the reflection wave by the second transmission wave from the ultrasonic frequency. Therefore, it is not necessary to set the first set distance time T1 to be long, as long as it is equal to or longer than the time when the first direct wave disappears. Therefore, by changing the transmission frequency for each transmission wave, it is possible to speed up the distance measurement by ultrasonic waves.

Next, the operation of the distance control means 1 and the control interval storage means 8 will be described with reference to FIG.

FIG. 4 is a diagram showing a time chart of a transmitted wave, a received wave, and a reflected wave of ultrasonic waves. However, the vertical axis represents the ultrasonic wave amplitudes A1 and A2, and the horizontal axis represents the time t.
Further, in FIG. 4, similarly to FIG. 3, the first distance time T1 is measured from the distance range x1 to x2 by the first transmission wave, and the second distance measurement is performed from the distance range x3 to x4 by the second transmission wave. The result of measuring the time T2 is shown.

As shown in FIG. 4, the distance range x1 to x2
Even if the first set distance time T1 for measuring the distance between them and the second set distance T2 for measuring the distance between the distance ranges x3 and x4 are reached, no received wave is received. That is, the distance L between the measuring object and the distance measuring device is the maximum distance x in the set distance range.
It can be seen that it is 4 or more. Therefore, as shown in an example of FIG. 4, the minimum distance time Tmax obtained by adding the first set distance time T1 and the second set distance time T2 is set as the control interval T, and the control interval is set after the distance measurement is started. If it is T time or more, the distance between the measurement object and the distance measuring device is set to the maximum distance x4 or more. Then, when the control interval T time has elapsed, the first transmission wave is transmitted again, and distance measurement is performed. Therefore, the distance measurement can be performed in the cycle of the control interval T time, and the distance measurement can be speeded up.

The shortest control interval T time in FIG. 4 is the sum of the first set distance time T1 and the second installation time T2, but is generally stored in the sending condition storage means 3. It may be equal to or longer than the minimum time obtained by adding all the ultrasonic wave transmission times of the ultrasonic wave transmitter 4.

The distance control means 1 outputs a distance control signal to the set distance range storage means 2 so that the distance measurement is performed in the cycle of the control interval T stored in the control interval storage means 8. Further, the distance calculation means 6 refreshes the distance measurement from the distance measurement at each control interval T by the control interval storage means 8, and when the received wave is not input within the control interval T, the object is measured. Distance output of the distance measuring device is performed assuming that the distance L is equal to or larger than the maximum distance set.

In this embodiment, set distance range storage means for setting a plurality of measurement distance ranges, and sending condition storage for storing ultrasonic wave sending conditions according to a plurality of set distances stored in the set distance range storage means. It is equipped with a means, stores the optimum sending condition to the ultrasonic sending unit in the set range, and performs distance measurement by ultrasonic waves under the condition, so that distance measurement can be performed more easily in a wider range. .

In the present embodiment, the output of the set distance range is started by inputting the distance control signal from the distance control means to the set distance range storage means, and the distance measurement is performed after the distance control signal is input. Therefore, since the set distance range currently measured can be accurately known by examining the time from the distance control signal, more accurate distance measurement can be performed.

In this embodiment, the output of the set distance range is stopped when the distance of the distance object can be measured in the set distance range storage means, and the distance measurement is stopped when the distance can be measured. By doing so, it is possible to speed up the distance measurement since no time is wasted.

In this embodiment, the distance control means outputs the distance control signal at intervals of the distance measurement time stored in the distance measurement time storage means. Since distances are measured at intervals, the latest distance information can always be collected.

Further, in the present embodiment, the distance measurement time stored in the distance measurement time storage means is equal to or longer than the minimum time determined by the set distance stored in the set distance range storage means. By setting the minimum time, the distance can actually be measured, but the distance measurement time is short, so the next distance measurement cycle will not start and the distance measurement will not stop. It can improve reliability.

Further, in this embodiment, if the distance cannot be measured by the time interval stored in the distance measurement time storage means, it is determined that the distance to the object to be measured is equal to or larger than the set range. Therefore, by determining that the measurement target is at or above the set distance, it is possible to speed up the measurement time without wasting time during the distance measurement.

Further, in the present embodiment, when the set distance is short, the sending condition is to shorten the sending time of the ultrasonic wave. By reducing the sending energy of the ultrasonic wave, the distance is accurately set even when the set distance is short. Can be measured. Further, since shortening the sending time can be realized with a simple configuration, it is possible to more easily perform distance measurement in a wide range.

Further, in this embodiment, the transmission condition storage means stores the frequency of the ultrasonic wave and outputs the frequency of the ultrasonic wave according to the setting range by the setting range storage means. By changing the frequency of the sound wave, even if a large number of reflected waves of the ultrasonic wave are returned to the ultrasonic wave receiving sensor at one time, by checking the setting range of the frequency, it is possible to obtain more accurate detection without false detection. The distance of the measuring object can be measured accurately.

(Second Embodiment) Next, a second embodiment of the present invention will be described.

The configuration and operation of the second embodiment are obtained by adding the configuration and operation of changing the ultrasonic wave transmission conditions depending on the type of the object to be measured to the configuration and operation of the first embodiment. Therefore, in the following, the configuration and operation of the second embodiment will be described focusing on the differences from the configuration and operation of the first embodiment, and other configurations and operations will be the same as those of the first embodiment. The description is omitted.

In FIG. 5, reference numeral 9 denotes a measurement state information storage means, which stores the measurement state information such as the color, material, ultrasonic angle, frequency, etc. of the measuring object to be measured by ultrasonic waves, When the distance control signal from the control means 1 is input, the measurement state information is output. The measurement state sending condition storage means 10 determines the sending condition of the ultrasonic wave sending part 4 from the measurement state information by the measurement state information storing means 9 and outputs it as the measurement state sending condition.

Next, the operation of the second embodiment will be described.

First, the operation of the measurement state sending condition storage means 10 will be described with reference to FIGS. 6 and 7. 6 and 7
FIG. 4 is a diagram showing a time chart of a transmitted wave, a received wave, and a reflected wave of ultrasonic waves. However, the vertical axis represents the ultrasonic amplitude A.
1, A2, and the horizontal axis represents time t. Further, FIG. 6 shows a measurement result when a sofa is used as the measurement target, and FIG. 7 shows a measurement result when a wooden wall is used as the measurement measurement target.

Since the sofa is made of a softer material than a wooden wall, it is difficult for ultrasonic waves to be reflected. Therefore, as shown in FIGS. 6 and 7, the amplitude of the received ultrasonic wave reflected by the sofa is smaller than that of the received ultrasonic wave reflected by the wooden wall. In other words, in order to detect the distance to the sofa stably,
The energy of the transmitted waves of ultrasonic waves must be increased. Therefore, for the purpose of short-distance measurement, ultrasonic waves with low energy are sent to measure the distance to the object to be measured, and if the measurement is impossible, ultrasonic waves with higher energy are sent although the measurable range is narrowed. This makes it possible to measure the distance of an object to be measured, such as a sofa, where ultrasonic waves are less likely to be reflected. In the above, the operation of the distance measuring device is described with the information of the measuring object as the material of the measuring object, but the angle, distance, structure of the measuring object, the angle of the ultrasonic wave of the ultrasonic measuring device, the product number, etc. Any information may be used as long as it has an influence on the reflectance of the ultrasonic wave as shown in FIG.

As described above as the material of the object to be measured, the measurement state delivery condition storage means 10 stores the delivery conditions of the ultrasonic wave delivery section 4 according to the measurement state information stored in the measurement state information storage means 9. I remember. When the information of the measurement object is input from the measurement state information storage unit 9, the measurement state transmission condition storage unit 10 outputs the transmission conditions of the corresponding ultrasonic transmission unit 4 to the ultrasonic transmission unit 4.

In this embodiment, the ultrasonic wave sending conditions are changed according to the state of the measuring object as the distance measuring object and the state of the distance measuring device for measuring the distance to the measuring object by ultrasonic waves. Yes, for example, first, by transmitting an ultrasonic wave having a small energy, the direct wave of the ultrasonic wave is reduced to enable a short distance measurement, and then,
By transmitting ultrasonic waves with large energy, the reflected waves of ultrasonic waves are increased to enable distance measurement when the distance to the measurement target is long or when the measurement target is a material that is difficult to reflect. Is. Therefore, the distance of the measuring object can be measured in any case by changing the ultrasonic wave transmission energy by the ultrasonic wave transmitting sensor according to the state of the measuring object and the state of the distance measuring device.

(Embodiment 3) Next, a third embodiment of the present invention will be described.

The configuration and operation of the third embodiment are as follows:
The configuration and the operation of changing the ultrasonic wave transmission conditions according to the distance between the measurement object and the distance measuring device are added to the configuration and the operation of the embodiment. Therefore, in the following, the configuration and operation of the third embodiment will be described focusing on the differences from the configuration and operation of the first and second embodiments, and other configurations and operations will be described in the first and second embodiments. The detailed description will be omitted as it is the same as.

In FIG. 8, reference numeral 11 is a set distance range storage means, which stores a plurality of distances to be measured by ultrasonic waves and set distance ranges. When the distance control signal from the distance control means 1 is input, the set distance range storage means 11 sequentially outputs the stored set distance ranges to the distance sending condition storage means 12.
The distance sending condition storage means 12 is the set distance range storage means 1
The set distance range output by 1 is input, and the sending condition to the ultrasonic wave sending unit 4 is output from the set distance range. Also, 13
Is a distance determining means, which receives the set distance by the set distance storing means 11, the sending condition by the distance sending condition storing means 12, and the received wave input signal by the ultrasonic wave receiving unit 5. The distance determining means 13 determines whether or not there is an object to be measured in the set distance range based on the set distance range of the set distance range storage means 11 and the sending conditions of the distance sending condition storage means 12, and if there is a measuring object, The set distance range is output as distance output.

Next, the operation of the third embodiment will be described.

FIG. 9 is a diagram showing the set distance x and the ultrasonic wave transmission time ts by the ultrasonic wave transmission unit 4. However, the horizontal axis is shown as the set distance x and the transmission time ts.

As shown in FIG. 9, the longer the set distance x measured by ultrasonic waves, the longer the transmission time ts. This is because the reflected wave from the measurement object becomes smaller as the set distance x becomes longer, and the energy of the transmitted wave must be increased. The set distance range storage means 11 continuously outputs the set distance x when the distance control signal from the distance control means 1 is input. Although a method of changing the ultrasonic wave transmission time ts with respect to the set distance x has been described above with reference to FIG. 9, the point is that a method of changing the energy of the transmission wave is essential, and other methods are used. A method such as a method or a method of changing the amplitude of the transmitted wave may be used. The distance transmission condition storage means 3 outputs the ultrasonic wave transmission conditions corresponding to the set distance x of the set distance range storage means 11, that is, the ultrasonic wave transmission time ts according to the example of FIG.

Next, the operation of the distance determining means 13 will be described with reference to FIG.

FIG. 10 is a diagram showing a time chart of a transmitted wave, a received wave, and a reflected wave of ultrasonic waves. However, the vertical axis represents the ultrasonic wave amplitudes A1 and A2, and the horizontal axis represents the time t.

In FIG. 10, the distance x to the object to be measured
Then, the time difference Δt between the transmitted wave and the received wave of the ultrasonic wave is Δt (msec) = x (cm) / 17 (cm / msec) (2). That is, the time difference Δt = x with respect to the set distance x
It is possible to know whether or not the measurement target is at the measurement distance x by determining whether or not the received wave of the ultrasonic wave is input at / 17.

The distance judging means 13 determines the time difference Δt1 = (t11) -from the time t11 when the sending condition of the distance sending means 12 is output and the received wave input signal t12 of the ultrasonic wave receiving section 5.
(T12) is calculated, and it is determined whether or not the time difference Δt according to the equation (2) at the set distance x by the set distance range storage means 11 is the same value as Δt1. If it is determined that they are the same value, the distance output is performed assuming that the measuring object is present at the set distance x.

In this embodiment, the ultrasonic wave transmission conditions are changed in accordance with the distance between the object to be measured and the distance measuring device. When the target distance is long, the ultrasonic wave is not transmitted. By increasing the delivery energy and reducing the delivery energy of ultrasonic waves when the distance is short, the distance of the measurement object can be measured at any distance. Further, since the pinpoint distance measurement for measuring whether or not the measurement object exists at the set distance is performed, the distance range of the measurement object can be measured, the distances of a plurality of measurement objects can be simultaneously measured, and the like. .

[0109]

As described above, according to the present invention, the ultrasonic wave transmitted by the ultrasonic wave transmitter is changed according to the state of the measuring object, the state of the distance measuring device, the distance between the distance measuring device and the measuring object, and the like. By changing the transmission energy, it is possible to provide a distance measuring device using ultrasonic waves without limiting the measurement range.

Further, it is possible to provide a distance measuring device using ultrasonic waves, which can easily perform the distance measurement in a wide range.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of a distance measuring device according to a first embodiment of the present invention.

FIG. 2 is a time chart showing ultrasonic transmission waves, reception waves, and reflected waves.

FIG. 3 is a time chart showing operations of a set distance range storage means and a sending condition storage means.

FIG. 4 is a time chart showing the operation of the control interval storage means.

FIG. 5 is a block diagram showing a configuration of a distance measuring device according to a second embodiment of the present invention.

FIG. 6 is a time chart showing the operation of the measurement state information storage means and the measurement state transmission condition storage means.

FIG. 7 is another time chart showing the operation of the measurement state information storage means and the measurement state transmission condition storage means.

FIG. 8 is a block diagram showing a configuration of a distance measuring device according to a third embodiment of the present invention.

FIG. 9 is a diagram showing a relationship between a set distance and a sending time.

FIG. 10 is a time chart showing the operation of the distance determination means.

FIG. 11 is a block diagram showing the configuration of a conventional distance measuring device.

[Explanation of symbols]

1 Distance control means 2 Setting distance range storage means 3 sending condition storage means 4 Ultrasonic transmitter 5 Ultrasonic receiver 6 Distance calculation means 7 Distance measurement stopping means 8 Control interval storage means 9 Measurement state information storage means 10 Measuring state sending condition storage means 11 setting distance range storage means 12 Distance sending condition storage means 13 Distance judgment means

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Keiko Noda             1006 Kadoma, Kadoma-shi, Osaka Matsushita Electric             Sangyo Co., Ltd. (72) Inventor Yoji Uitani             1006 Kadoma, Kadoma-shi, Osaka Matsushita Electric             Sangyo Co., Ltd. F term (reference) 2F068 AA06 BB01 DD03 DD05 FF03                       FF12 FF25 PP03 PP05 QQ42

Claims (11)

[Claims] 1. A distance measuring device for changing ultrasonic wave sending conditions according to a state of a distance measuring device for measuring a distance to an object to be measured by ultrasonic waves or a state of the object to be measured. 2. A distance measuring device for measuring a distance to an object to be measured by ultrasonic waves, and the object to be measured according to the distance.
A distance measuring device that changes the ultrasonic wave transmission conditions. 3. An object to be measured by ultrasonic waves, comprising: a set distance range storage means for storing a plurality of set distance ranges; and a delivery condition storage means for storing an ultrasound delivery condition according to the plurality of set distance ranges. A distance measuring device that measures the distance to an object. 4. An object to be measured by ultrasonic waves, comprising: set distance range storage means for storing a plurality of set distance ranges; and delivery condition storage means for storing an ultrasound delivery condition according to the plurality of set distance ranges. The distance measuring device according to claim 1 or 2, which measures a distance to an object. 5. A distance control means is provided, and the set distance range storage means starts outputting the set distance range when a distance control signal from the distance control means is input.
Alternatively, the distance measuring device according to item 4. 6. When the distance of the measuring object can be measured,
The distance measuring device according to claim 5, wherein the set distance range storage means stops outputting the set distance range. 7. The distance measuring device according to claim 5, further comprising distance measuring time storage means for storing distance measuring time, wherein the distance control means outputs a distance control signal at intervals of the distance measuring time. 8. The distance measuring device according to claim 7, wherein the distance measurement time stored in the distance measurement time storage means is equal to or longer than the minimum time determined by the set distance range stored in the set distance range storage means. 9. The distance control means sets the distance to the object to be measured stored in the set distance range storage means when the distance measurement cannot be performed at the distance measurement time intervals stored in the distance measurement time storage means. The distance measuring device according to claim 7, wherein it is determined that the distance is equal to or larger than the distance range. 10. The transmission condition storage means shortens the ultrasonic wave transmission time when the set distance range is short.
The distance measuring device according to any one of 1. 11. The transmission condition storage means stores the frequency of the ultrasonic wave, and outputs the frequency of the ultrasonic wave according to the set distance range by the set distance range storage means. Distance measuring device.