JP2006317356A - Ultrasonic human body sensor, toilette device having same, and human body detection method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To detect a human body in a small space like a toilette space where many reflective members exist and in a situation in which complicated reflections are generated. <P>SOLUTION: An ultrasonic wave is intermittently transmitted toward a monitored space while receiving a reflected wave corresponding to the transmission. Each time intermittent transmission is made, a reception signal output correspondently to the reflected wave is sequentially sampled in a prescribed cycle and A/D converted into reception waveform data comprising a plurality of sample values. Then, among the waveform data, reception waveform data obtained at times when no human body exists are stored as referential waveform data. A comparison is made for each sample value between sequentially output reception waveform data and the referential waveform data. Differences between the sample values are sequentially added up from a headmost sample value. When the additional value exceeds a first threshold, it is determined that a human body exists in the monitored space. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an ultrasonic human body sensor, and more particularly to an ultrasonic human body sensor that can detect a human body even in a situation where a complicated reflection occurs in a space that is narrow like a toilet space and has many reflecting members.

  Conventionally, an ultrasonic sensor has been used as a sensor for detecting an object in a predetermined area. For example, an obstacle sensor for detecting an obstacle in front of or behind a car, an ultrasonic for confirming the presence of a person in an elevator. It is often used as a human body sensor or the like (for example, see Patent Document 1).

  This ultrasonic sensor is a sensor using a piezoelectric element, and detects a human body based on transmission / reception of ultrasonic waves by this piezoelectric element. Hereinafter, the operation principle of the ultrasonic sensor will be specifically described with reference to the drawings. FIG. 13 is an operation principle diagram when the ultrasonic sensor is used as a distance sensor.

  The ultrasonic sensor has a piezoelectric element. When a pulse voltage in the ultrasonic region is applied to the piezoelectric element, the piezoelectric element distorts and vibrates, and an ultrasonic wave is transmitted as shown by a transmission waveform A. The transmitted wave hits the human body, and the reflected ultrasonic wave is received by the piezoelectric element as the received waveform B.

  In this way, when the ultrasonic wave is transmitted as the transmission waveform A and received as the reception waveform B after T time, if the ultrasonic wave propagation velocity V is V, the distance to the object is V × T / 2 to know. Therefore, it is possible to detect the distance or presence of the human body by converting the received reflected wave into a voltage signal and calculating V × T / 2 by the processing circuit.

  For example, when it is attempted to detect the presence of a human body or an obstacle in a space monitored by an ultrasonic sensor, if the ideal situation is that there is no object that blocks or reflects ultrasonic waves in the middle, the above-mentioned It can be received at the time required for such theoretical calculations, and the presence of human bodies and obstacles can be captured.

  In addition, when trying to detect whether or not a person is present in an elevator having a relatively wide space, a fixed object is stored in advance as a reference waveform based on a reflected wave waveform when no person is present, and the reference There is one that determines that there is a person when a reflected wave having a difference from the waveform is received (see, for example, Patent Document 2).

JP-A-4-38363 JP-A-56-160673

  However, if the ultrasonic sensor configured by the above-described conventional technique is used to detect a human body entering and exiting a narrow space such as a toilet, the reflected wave of the ultrasonic wave toward the human body hits a wall or a figurine. Then, irregular reflection occurs, and many reflected waves are generated everywhere in one transmission. In addition, there is one that reflects twice on the object like a reflected wave C in FIG. Since ultrasonic waves are waves that propagate in the air, when a large number of reflections occur in this way, the reflected waves overlap each other and become stronger, weaker, or sometimes lost.

  In addition, the reflected wave is attenuated when it hits the human body, but the attenuation ratio varies greatly depending on the material such as clothes worn by the person, and the direction of the reflection is various.

  In this way, the magnitude and direction of the amplitude of the reflected wave is not uniform, so the reflected wave from the human body is extracted based on the difference in waveform between when there is a person and when there is no person, as in the past. It is difficult to detect the human body from the position.

  The present invention has been made in view of the above problems, and an ultrasonic human body sensor that can easily detect a human body in a situation where a complicated reflection occurs in a space that is narrow like a toilet space and has many reflecting members. The purpose is to provide.

  In order to solve such a problem, the invention according to claim 1 is directed to ultrasonic transmission / reception means for intermittently transmitting ultrasonic waves toward a monitoring space and receiving reflected waves for the transmission, and the ultrasonic transmission / reception means. Each time the ultrasonic wave is transmitted intermittently, the received signal output corresponding to the reflected wave is sequentially sampled at a predetermined period, A / D converted, and a received waveform composed of a plurality of sampling values Received waveform conversion means as data; reference waveform storage means for storing received waveform data obtained at a timing when no human body is present as reference waveform data out of the received waveform data output from the received waveform conversion means; The received waveform data sequentially output from the received waveform converting means is compared with the reference waveform data to determine the presence or absence of a human body in the monitoring space, and the result is output. An ultrasonic human body sensor comprising: a determination unit that compares the received waveform data with the reference waveform data for each sampling value, and calculates a difference between the sampling values from the first sampling value. A sequential addition is performed, and when the added value exceeds a first threshold, it is determined that a human body exists in the monitoring space.

  Further, the invention according to claim 2 is characterized in that the determination means is located at a position in the monitoring space corresponding to the sampling timing of the sampling value when the added value exceeds the first threshold value or closer to the position. It is characterized in that it is determined that a human body exists and the position information is stored in a storage means.

  Moreover, the invention according to claim 3 corresponds to the sampling timing of the sampling value when the determination value exceeds the first threshold value even when the addition value exceeds the first threshold value. If it is determined that the position in the monitoring space is a position more than a predetermined distance from the position information already stored in the storage means, the update of the position information stored in the storage means is not performed. Features.

  In the invention according to claim 4, the determination means may calculate the sampling values before and after the sampling value when the addition value exceeds the first threshold value, even when the addition value exceeds the first threshold value. When the difference is less than the second threshold, it is not determined that the human body exists at or near the position in the monitoring space corresponding to the sampling timing of the sampling value when the first threshold is exceeded. It is characterized by.

  The invention according to claim 5 is characterized in that the determination means can change a range of the monitoring space.

  The invention described in claim 6 is a toilet device including the ultrasonic human body sensor described in any one of claims 1 to 5.

  According to the seventh aspect of the present invention, human body detection is performed in which ultrasonic waves are intermittently transmitted toward a monitoring space, and the presence / absence of a human body is determined using ultrasonic transmission / reception means for receiving reflected waves in response to the transmission. Each time the ultrasonic wave is transmitted intermittently by the ultrasonic wave transmitting / receiving means, the reception signal output corresponding to the reflected wave is sequentially sampled at a predetermined period and A / D converted, Receiving waveform data composed of a plurality of sampling values, storing received waveform data obtained at a timing when no human body is present among the received waveform data as reference waveform data, and receiving waveform data Is compared with the reference waveform data for each sampling value, and the difference between the sampling values is added sequentially from the first sampling value. When a exceeds a first threshold value, and wherein determining a human body is present, it is a human body detection method having the monitoring space.

  According to the first aspect of the present invention, the received waveform data and the reference waveform data are compared for each sampling value, and the difference between the sampling values is sequentially added from the first sampling value, and a human body is expected. By determining that there is a human body when the first threshold value is exceeded, signals below the threshold value that were not used in the past are also effectively used, and fine and complex changes in the vicinity of the sensor are accumulated, improving noise resistance. The human body detection rate can be improved.

  In addition, according to the invention described in claim 2, by having a storage unit that can determine the position where the human body exists and stores the position corresponding to the sampling timing when the addition value exceeds the first threshold, It can be easily compared whether or not the detection position of the human body has changed beyond a predetermined distance.

  According to the third aspect of the invention, the position in the new monitoring space obtained as a result of the sequential addition from the leading sampling timing is abruptly farther than the predetermined value compared with the stored position information. If this happens, the waveform disappears due to the interference of the reflected wave, or the received signal due to multiple reflections is considered to be a change in the received waveform data that is not related to the movement of the human body, and is ignored to increase the human body detection probability. Is possible.

  According to the fourth aspect of the present invention, it is determined that the threshold value is exceeded due to accumulation of the difference between the sampling values that mean noise, and the detection probability of the human body can be increased.

  According to the invention described in claim 5, the farthest point for determining the presence or absence of the human body can be set, and various monitoring spaces can be handled.

  Further, according to the invention described in claim 6, by applying the ultrasonic human body sensor to the toilet device, the probability of detecting the human body in the toilet device can be increased.

  According to the seventh aspect of the present invention, the difference between the received waveform data when there is no human body after A / D conversion and when there is no human body is compared with the threshold value immediately as in the conventional case, and less than that is ignored. Instead of reducing the information, the detection accuracy can be easily increased by sequentially adding the differences of the received waveform data and comparing with the combination of the value and the threshold value.

  An ultrasonic human body sensor according to an embodiment of the invention will be specifically described below with reference to the drawings. FIG. 1 is a block diagram showing the overall configuration of an ultrasonic human body sensor according to an embodiment of the present invention.

  As shown in FIG. 1, an ultrasonic human body sensor 10 according to an embodiment of the present invention includes an oscillating means 1, a booster circuit 2, an ultrasonic transmitting / receiving means 3, a receiving / detecting circuit 4, and a received waveform converting means 5. And a reference waveform storage means 6 and a determination means 7.

  The oscillating means 1 is controlled by the judging means 7 and generates a pulse signal in the ultrasonic frequency band (hereinafter referred to as “ultrasonic region pulse”). The ultrasonic region pulse thus generated is Are output to the booster circuit 2. The determination unit 7 controls the oscillation unit 1 so as to intermittently output ultrasonic region pulses that are continuous for a predetermined time at predetermined intervals. This predetermined time is a time required for the piezoelectric element inside the ultrasonic transmitting / receiving means 3 to vibrate to emit ultrasonic waves, and is usually about several hundreds of μs. Further, the predetermined interval varies depending on temporal sensitivity for detecting a human body, and is 100 ms in the embodiment of the present invention.

  The ultrasonic region pulse output from the oscillating means 1 is boosted by the booster circuit 2, and the ultrasonic wave transmitting / receiving means 3 intermittently monitors the ultrasonic waves for a predetermined time with the boosted high voltage ultrasonic region pulse signal. (Hereinafter referred to as “monitoring space”). Corresponding to the reflected wave for each transmission wave transmitted intermittently, the output reception signal is detected via the reception / detection circuit 4 and taken into the reception waveform converting means 5.

  The reception signal output corresponding to the reflected wave every time transmission is intermittently sampled in a predetermined cycle after the reception mask is completed, and the signal is converted to A via the A / D conversion means of the reception waveform conversion means 5. / D converted and converted into received waveform data composed of a plurality of digital sampling values.

  The above-described reception mask is a piezoelectric element in which the ultrasonic transmission / reception means 3 is integrated with a transmission / reception unit, and is necessary for performing transmission and reception with the same piezoelectric element. Immediately after transmission of the ultrasonic transmission / reception means 3, vibration during transmission remains, which is generally referred to as “reverberation”. The time until the reception signal is stabilized after the reverberation is attenuated, the reception waveform conversion means 5 is started. A process for delaying the reception is a reception mask.

  In the embodiment of the present invention, the reception mask is 1 ms, and then the received signal is sampled 100 times in a cycle of 50 μS, thereby being converted into received waveform data composed of 100 sampling values.

  The range of the received waveform data to be sampled is a time range of 1 to 6 ms after transmission. When the sound speed is 340 m / s, sampling is performed by dividing the interval into 100 equal parts within a distance range of 17 cm to 102 cm. . That is, the distance D [cm] corresponding to the nth sampling data is calculated by (D = 17 + 0.85 × n).

  The received waveform data output from the received waveform conversion means 5 is stored in the reference waveform storage means 6 as reference waveform data at a timing when there is no human body. After the acquisition of the reference waveform data, the digital value of the received waveform converting means 5 is sent as received waveform data directly to the determining means 7 without passing through the reference waveform storage means 6, and this reference waveform data and received waveform converting means are sent. The received waveform data sequentially output from 5 is compared and calculated. As a result of this comparison calculation, the determination means 7 determines the presence or absence of a human body in the monitoring space and outputs a detection signal.

  The comparison operation by the judging means 7 compares the received waveform data with the reference waveform data for each sampling value, sequentially adds the difference of the sampling values from the first sampling value, and the added value sets the first threshold value. When it exceeds, it is determined that a human body exists in the monitoring space. The oscillating means 1, the received waveform converting means 5, the reference waveform storing means 6, and the judging means 7 are computers 8, which are contained in one package.

  2 to 4 will be described as specific examples obtained as a result of the configuration of FIG. 2 to 4 are explanatory diagrams of the operation of the determination means of the ultrasonic human body sensor 10 according to the embodiment of the present invention. Reference waveform data, received waveform data, differential waveform data obtained by taking a difference between both signal waveform data, and difference The two-dimensional display figure of the data which sampled the waveform data and added sequentially from the head sampling value is shown. The horizontal axis indicates the sampling timing number indicating the order of sampling timing (hereinafter referred to as “timing number”), and the vertical axis indicates the sampling value.

  First, the operation of the ultrasonic human body sensor 10 in a state where a human body wearing normal clothes is present at a distance of about 40 cm from the ultrasonic transmission / reception means 3 will be specifically described with reference to FIG.

  FIG. 2A shows received waveform data when the human body is not in the monitoring space, that is, reference waveform data. In the present embodiment, since the received signal is received waveform data by sampling 100 times, the timing numbers are from 1 to 100 in the sampling order.

  FIG. 2 (B) is a diagram showing received waveform data in a state where a human body wearing normal clothes is present at a distance of about 40 cm from the ultrasonic transmission / reception means 3, and a timing number compared to FIG. 2 (A). Sampling values near 10, 30, 85 are high.

  FIG. 2C shows a result of performing a difference calculation by comparing the reference waveform data shown in FIG. 2A and the received waveform data shown in FIG. 2B for each sampling value at the same sampling timing. That is, the calculation of the difference value obtained by subtracting the sampling value of the timing number n of the reference waveform data from the sampling value of the timing number n of the received waveform data is performed sequentially from the first 1 of the timing number to the timing number 100.

  In FIG. 2D, the determination means 7 sequentially adds the difference value for each sampling value between the received waveform data and the reference waveform data shown in FIG. The result is shown.

  The determination means 7 is configured to sequentially add from the sampling value of the leading timing number 1 in this way, and to determine that a human body exists in the monitoring space when the addition value exceeds the first threshold value. ing. In the present embodiment, the first threshold is set to 200, and the timing number when the added value exceeds 200 is 24. In the present embodiment, since the distance D [cm] of the n-th sampling value can be calculated by (D = 17 + 0.85 × n), the determination unit 7 is located at a position 37 cm from the ultrasonic transmission / reception unit or from 37 cm. It is determined that the human body exists within a close range.

  Next, the operation of the ultrasonic human body sensor 10 in a state where there is a human body wearing fluffy clothes at a distance of about 40 cm from the ultrasonic transmission / reception means 3 will be specifically described with reference to FIG. Note that FIG. 3A is a diagram illustrating reference waveform data, which is the same as FIG. 2A, and thus description thereof is omitted here.

  FIG. 3B is a diagram showing received waveform data in a state where there is a human body wearing fuzzy clothes at a distance of about 40 cm from the ultrasonic transmission / reception means 3, and the human body is at the same distance but fuzzy. Since the ultrasonic waves are irregularly reflected by the clothes, the sampling value is generally lower than that in FIG.

  FIG. 3C shows a result of calculating a difference value for each sampling value between the received waveform data and the reference waveform data by the determination unit 7, and FIG. 3D is a diagram of FIG. The result of sequentially adding the difference value for each sampling value between the received waveform data and the reference waveform data from the sampling value of the leading timing number 1 shown in FIG.

  Here, since the timing number when the added value exceeds 200 is 24, the determination unit 7 determines that the human body exists at a position 37 cm or closer to 37 cm from the ultrasonic transmission / reception unit.

  Because the human body that entered the surveillance space wears fuzzy clothes, the difference value becomes small and difficult to distinguish from noise etc., but by adding the difference value in this way, It becomes possible to detect the distance where the human body exists.

  Next, the operation of the ultrasonic human body sensor 10 in a state where no human body is present will be specifically described with reference to FIG. Note that FIG. 4A is a diagram showing reference waveform data, which is the same as FIG. 2A, so the description thereof is omitted here.

  FIG. 4B is a diagram illustrating reference waveform data in a state where the human body is not in the monitoring space and is receiving reflected waves and noise such as toilet mats and fluctuations caused by wind.

  FIG. 4C shows the result of calculating the difference value for each sampling value between the received waveform data and the reference waveform data by the determination unit 7, and FIG. 4D is the result of FIG. The result of sequentially adding the difference value for each sampling value between the received waveform data and the reference waveform data from the sampling value of the head timing number (n = 1) shown in FIG.

  Here, the determination means 7 has a timing number of 85 (89 cm in terms of distance) when the added value exceeds 200, but in this embodiment, the monitoring space is 80 cm from the ultrasonic human body sensor 17. Since it is set within the distance, it is determined that no human body exists in the monitoring space. This monitoring space is set in the determination means 7 by the fourth threshold value.

  In addition, when the monitoring space is set to the maximum space that can be monitored, that is, within a distance of 102 cm from the ultrasonic human body sensor 10, even if the added value exceeds 200, the added value is When the difference between the sampling values of the sampling timings before and after the sampling value of the sampling timing when exceeding 200 is less than the second threshold, it is assumed that the human body is present at a position of 85 cm or a range of 85 cm from the ultrasonic transmission / reception means. Is not judged. In the present embodiment, the second threshold is set to 25.

  As described above, even when the added value exceeds the first threshold, when the difference between the sampling values before and after the sampling value when the first threshold is exceeded is less than the second threshold, the first Since it is not determined that a human body is present at or near the position in the monitoring space corresponding to the sampling timing of the sampling value when the threshold value is exceeded, no erroneous detection due to noise will occur.

  Further, since the monitoring space can be changed within the space that can be monitored by changing the fourth threshold value, the setting and changing of the monitoring space is facilitated.

  FIG. 5 shows periodically the received waveform data, reference waveform data, differential waveform data obtained by taking the difference between both signal waveform data, and data obtained by sampling the differential waveform data and sequentially adding them from the first sampling value. The result obtained continuously several times is displayed in a three-dimensional graph.

  FIG. 5A shows a case where the user performs an operation of entering the toilet, and shows a plurality of received waveform data moving from far away toward the ultrasonic human body sensor 10. The X axis (horizontal direction in FIG. 5) indicates the sampling timing, the Y axis (vertical direction in FIG. 5) indicates the strength of the received signal waveform, and the Z axis (depth direction in FIG. 5) indicates the elapsed time. Since no human body is detected from S1 to S12 on the Z axis, the data is the same as the reference waveform data of FIG.

Received signals are obtained in various sizes, from 1 to 27 on the X axis, and strong received signals are obtained at the intersections in the vicinity of the X axis 27 near the Z axis S21. Is difficult.
FIG. 5B shows reference waveform data for a plurality of times in a state where no human body exists. Since it is the reference value stored in the reference waveform storage means, there is no change in the Z-axis direction representing the passage of time unless it is stored again. A strong signal that is greatly affected in the Y-axis direction from 0 to around 10 in the X-axis direction shows reverberation.

  FIG. 5C shows differential waveform data obtained by digitally calculating and subtracting reference waveform data from received waveform data. The reverberation part at the head of the A / D conversion sampling timing of the received waveform data in FIG. 5A is removed by the calculation for calculating the difference, and only the received signal remains as the human body moves. . It has become clear that there are a large number of reflected waves in addition to the received signals having strong intersections near the X axis 27 near the Z axis S21 described above.

  FIG. 5D shows the result of sequentially adding the differential waveform data of FIG. 5C from the first sampling value. On the Z axis S19, it can be determined that the first threshold is exceeded at the X axis 10. Similarly, the first threshold value does not exceed on the Z axis S15. When the first threshold value is exceeded, a determination is made in comparison with the second threshold value and the fourth threshold value, and a detection signal is output.

  Next, the ultrasonic human body sensor 10 configured as described above will be specifically described below with reference to the drawings. FIG. 6 is a flowchart of a main routine showing the operation of the ultrasonic human body sensor 10 in the present embodiment, FIG. 7 is a flowchart of a transmission / reception processing subroutine showing the operation of the ultrasonic human body sensor 10 in the present embodiment, and FIG. FIG. 9 is a flowchart of the difference calculation subroutine, FIG. 9 is a flowchart of the detection determination subroutine.

  As shown in FIG. 6, in the main routine for human body detection, when the power is turned on, the determination means 7 drives the oscillation means 1 to intermittently generate ultrasonic region pulses, thereby causing the ultrasonic transmission / reception means 3 to A reception signal that is intermittently transmitted with ultrasonic waves and is output corresponding to the reflected wave for each transmission is sequentially sampled at a predetermined cycle by the received waveform conversion means 5 and A / D converted, and a plurality of samplings are performed. Transmission / reception processing that constitutes reception waveform data composed of values is performed (step S001). The received waveform data obtained in step S001 is stored in the reference waveform storage means 6 as reference waveform data, and is used as data for calculation with received waveform data described later (step S002).

  In the present embodiment, the reference waveform is stored unconditionally (step S002) at a timing corresponding to immediately after the main routine is started, and immediately after the power switch is turned on in the case of a general electric device. It is also possible to determine that there is no person because there is no fluctuation in the received waveform data, and to update the storage of the reference waveform at any time under that condition.

  Next, the determining means 7 drives the oscillating means 1 to generate ultrasonic region pulses, thereby transmitting ultrasonic waves from the ultrasonic transmitting / receiving means 3 in the same manner as in step S001, performing transmission / reception processing, and from the human body. The received waveform data including the reflection of the light and the reflection from the installation member such as the toilet mat are acquired (step S003). The determination means 7 compares the acquired received waveform data with the reference waveform data, performs difference calculation processing in the order of A / D conversion sampling timing, and creates difference calculation processing data (step S004).

  Furthermore, the determination means 7 performs a detection determination process as to whether or not a human body exists based on the received waveform data, the reference waveform data, the difference calculation process data, and the like (step S005). Further, in order to acquire the received waveform data at a predetermined cycle, a timer of 100 ms is set after the end of the detection determination process (step S006), and the ultrasonic human body sensor 10 is directed toward the monitoring space in order to detect the presence or absence of a human body. The operation of transmitting and receiving ultrasonic waves is repeated intermittently.

  FIG. 7 is a flowchart of the transmission / reception process, and shows the detailed contents of the transmission / reception process (steps S001 and S003) of the main routine. This flowchart is processed as a subroutine.

  The ultrasonic human body sensor 10 outputs an ultrasonic transmission pulse from the ultrasonic transmission / reception means 3 (step S101), and takes time until the piezoelectric element is stabilized after transmission, in this example, 1 ms ( In step S102), in order to make the received signal into a plurality of sampling data, 1 is substituted into the timing number n to initialize the count (step S103).

  The reception waveform conversion means 5 performs A / D conversion on the reception signal taken in by the reception / detection circuit 4 (step S104), and outputs the result as data (1) (step S105). The timing number n is counted up (step S106), and the output of data (n) is repeated by repeating A / D conversion of the received signal until the timing number n reaches 100 times (step S107: No). When it is greater than 100 times (step S107: Yes), the process returns to the main routine (step S108). In this way, received waveform data composed of 100 sampling values of data (1) to data (100) is generated. In the case of this embodiment, the program is adjusted so that the loop time for repeating A / D conversion is 50 μs.

  FIG. 8 is a flowchart of the reference value storing process, showing the detailed contents of the reference value storing process (step S002) of the main routine. This flowchart is processed as a subroutine. In order to perform this reference value storage processing, the reference waveform storage means 6 receives the sampling values data (n) output from the received waveform conversion means 5 in order from data (1) in a state where no human body is detected. Therefore, the count is initialized by substituting 1 for the timing number n of the sampling value (step S201). Next, one piece of data (1) output from the received waveform converting means 5 is stored as reference waveform data ref (1) (step S202).

  Then, the reference waveform storage means 6 counts up the timing number n of the sampling value (step S203), and until the timing number n reaches 100 times (step S204: No), the data (n) is used as the reference waveform data ref. The operation of storing as (n) is repeated, and when n becomes larger than 100 times (step S204: Yes), the operation of storing the received waveform data as reference waveform data ends.

  Thereafter, the ultrasonic human body sensor 10 stores 100 as an initial value in storage means x for storing position information in the monitoring space (hereinafter abbreviated as position information storage means x. X is a numerical value corresponding to the timing number n). Is substituted (step S205), and the process returns to the main routine (step S206).

  FIG. 9 is a flowchart of the difference calculation process, showing the detailed contents of the difference calculation process (step S004) of the main routine. This flowchart is processed as a subroutine. The determination means 7 substitutes 1 for the timing number n and initializes the count (step S401). Next, the difference waveform data dif (n) is created by taking the difference between the received waveform data and the stored reference waveform data (step S402).

  When the dif (1) obtained from the difference is negative (step S403: Yes), the determination unit 7 replaces dif (1) with 0 (step S404), while if dif (n) is 0 or more ( Step S403: No), dif (1) is not replaced. Thereafter, the determination unit 7 up-counts the timing number n (step S405) and repeats the operations from step S402 to S404. That is, the sampling values from timing numbers 2 to 100 are taken in the order of timing numbers, the difference between the sampling values of the received waveform data and the reference waveform data is taken and corrected so that the difference does not become negative, and the difference waveform data dif (n) Is generated. Thereafter, when the timing number n becomes larger than 100 times (step S406: Yes), the process returns to the main routine (step S407).

  FIG. 10 is a flowchart of the detection determination process, showing the detailed contents of the detection determination process (step S005) of the main routine. This flowchart is processed as a subroutine. Since the determination means 7 performs arithmetic processing on the received signal as a plurality of digital sampling data, the count is initialized by substituting 1 into the timing number n of the sampling value, and sequentially added from the sampling value of the leading timing number 1 Sum (0), which is the initial value of the addition value of, is initialized to 0 (step S501).

  Next, the determination means 7 adds difference calculation processing data dif (), which is a difference value between the reference waveform data and the reception waveform data, to the reception waveform difference addition data sum (0) which is a value before adding the sampling value of timing number 1. 0) is added to generate reception waveform difference addition data sum (1) (step S502).

  Further, the determining means determines that sum (1) calculated in step S502 is equal to or higher than TH1, which is the first threshold for determining the presence of a human body (200 or higher in the present embodiment) (step S503: Yes). Because there is a human body, go to the next step.

  Even when the first threshold value is exceeded, when the slope before and after sum (n) is small, in order to determine that there is no human body in the position of timing number n, the determination means 7 uses sum (n) Is calculated as dif (n + 1) + dif (n), which is the amount of change in the received waveform difference addition data before and after the sampling value when exceeds the first threshold. If the result of dif (n + 1) + dif (n) is greater than or equal to the second threshold TH2 (step S504: Yes), sum (n) does not exceed the first threshold TH1 due to the accumulation of fine noise. A determination is made that a human body is detected.

  Next, even when sum (n) exceeds the first threshold value TH1, the result of dif (n + 1) + dif (n) is equal to or greater than the second threshold value TH2, and the determination means 7 determines that a human body exists, There are cases where reflection occurs multiple times in a narrow space such as a toilet, or ultrasonic waves interfere with each other, resulting in a received waveform that seems to have moved far away. For this reason, when the processing of not allowing a sudden change in the distance beyond what is normally considered and the reflection of the ultrasonic wave at a short distance, the determination means 7 determines that there is a human body at a short distance, and how sudden it is. Even if it is a distance change, the process of accepting the change to the short distance side unconditionally is simultaneously performed. The determination means 7 uses the position information stored in the position information storage means x as the position in the monitoring space corresponding to the timing number n of the sampling value when the first threshold value is exceeded for the above (until then, It is determined whether the distance is greater than a predetermined distance TH3 from the value stored as the human body is at that position (step S508).

  If the determination means 7 determines that the current timing number n has not moved to the side farther than the position information storage means x by a predetermined distance TH3, which is the third threshold value (step S510: No), the determination means 7 It is determined that a human body is present, and the value of n corresponding to the timing number when the first threshold value corresponding to the position in the monitoring space is exceeded is substituted into the position information storage unit x in the storage area of the determination unit 7, Information is updated (step S511).

  If sum (n), which is an addition value obtained by adding the difference between the sampling values of the received waveform data and the reference waveform data from the first sampling value, is less than the first threshold value TH1 (step S503: No), the timing number n is increased. Counting (step S505), and if the timing number n is 100 times or less (step S506: No), the process returns to step S502 and the addition is repeated.

  If it is determined in step S503 that sum (n) has exceeded the first threshold value TH1, the determination unit 7 determines the difference dif between the difference values before and after the timing number n of the added value exceeding the first threshold value. If (n + 1) + dif (n) is less than TH2, which is the second threshold value (step S504: No), the timing number n is counted up (step S505) as in step S503, and the timing number n is 100 times or less. If so (step S506: No), the process returns to step S502 and the addition is repeated.

  If the difference between the timing number n of the added value exceeding the first threshold and the position information stored in the position information storage means x is equal to or greater than a predetermined distance TH3, which is the third threshold (step S510: Yes), a plurality It is judged that the value of the timing number n is unreliable just because the received waveform has been moved as if the human body has moved far away due to the reflection and the interference between the ultrasonic waves. The stored position information is updated by adding 1 (step S507). The reason for adding 1 is to avoid that x cannot be updated forever.

  When the position information storage means x exceeds 100 (step S508: Yes), 100 is substituted into the position information storage means x (step S509), and when the position information storage means x does not exceed 100 (step S508). : No), the position information storage means x remains as it is.

  Next, the determination means 7 is greater than the fourth threshold TH4 for determining whether the position information storage means x is within the farthest point of the monitoring space where a human body that can be variably set must be detected (step S512: No). ) A human body is not detected (step S513), and if it is the following (step S512: Yes), a human body is detected (step S514), a detection signal is output, and the process returns to the main routine (step S515).

    When the timing number n is larger than 100 (step S506: Yes), it is determined by the determining means 7 that there is only noise, and the process returns to the main routine in the same flow from step S507 (step S515).

  As described above, according to the present invention, in order to reliably determine whether or not a human body exists in a monitoring space in which a large number of reflective objects are present using an ultrasonic human body sensor, The difference between the case where the human body exists and the case where the human body does not exist is sequentially added, and it is determined that the human body exists where the first threshold value is exceeded. When the change is small or when the detection position suddenly fluctuates far away, erroneous determination can be prevented by not determining that a human body exists.

  Moreover, the probability of detection of a human body becomes high by making the ultrasonic human body sensor 10 in this Embodiment into a toilet apparatus. The configuration will be described below with reference to FIGS. 11 and 12 show a toilet apparatus to which the ultrasonic human body sensor 10 according to the embodiment of the invention is applied.

  As shown in FIG. 11, a toilet apparatus 20 is disposed in a toilet room 30, and the ultrasonic human body sensor 10 is attached to the lower part of the toilet apparatus 20 at the front lower part thereof.

  When the presence of a human body is detected based on a detection signal from the ultrasonic human body sensor 10, the toilet apparatus performs control to open the toilet lid, and then performs control to close the toilet lid when it is detected that the human body has disappeared. .

  As shown in FIG. 12, the ultrasonic human body sensor 10 detects the presence / absence of a human body within a predetermined angle range within a distance D1 of the monitoring space S (hereinafter referred to as “monitoring space distance”). The monitoring space distance D1 can be set to the monitoring space up to a distance of D2 by changing the fourth threshold value of the ultrasonic human body sensor 10.

The block diagram which shows the whole structure of the ultrasonic human body sensor of embodiment of this invention. Operation | movement explanatory drawing of the determination means of the ultrasonic human body sensor of embodiment of this invention. Operation | movement explanatory drawing of the determination means of the ultrasonic human body sensor of embodiment of this invention. Operation | movement explanatory drawing of the determination means of the ultrasonic human body sensor of embodiment of this invention. 3 is a three-dimensional graph showing received waveform data, reference waveform data, difference waveform data obtained by taking a difference between the two signal waveform data, and difference waveform data at predetermined intervals according to an embodiment of the present invention. The control flowchart explaining the main routine of the ultrasonic human body sensor of embodiment of this invention. The control flowchart explaining the transmission / reception processing subroutine of embodiment of this invention. The control flowchart explaining the reference value storage process subroutine of embodiment of this invention. The control flowchart explaining the difference calculation process subroutine of embodiment of this invention. The control flowchart explaining the detection determination processing subroutine of embodiment of this invention. The figure which shows the installation condition of the toilet apparatus of embodiment of this invention. The figure which shows the installation condition of the toilet apparatus of embodiment of this invention. The figure explaining the operation principle of an ultrasonic wave.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Oscillation means 2 Booster circuit 3 Ultrasonic transmission / reception means 4 Reception / detection circuit 5 Received waveform processing means 6 Storage means 7 Determination means 8 Microcomputer

Claims (7)

Ultrasonic transmission / reception means for intermittently transmitting ultrasonic waves toward the monitoring space and receiving reflected waves for this transmission;
Each time the ultrasonic wave is transmitted intermittently by the ultrasonic wave transmitting / receiving means, the reception signal output corresponding to the reflected wave is sequentially sampled at a predetermined period and A / D converted, and a plurality of sampling values are obtained. Received waveform conversion means to be configured received waveform data;
Of the received waveform data output from the received waveform converting means, reference waveform storage means for storing received waveform data obtained at a timing when no human body is present as reference waveform data;
An ultrasonic human body sensor comprising: determination means for comparing the received waveform data sequentially output from the received waveform converting means with the reference waveform data to determine the presence or absence of a human body in the monitoring space and outputting the result In
The determination unit compares the received waveform data with the reference waveform data for each sampling value, sequentially adds the difference between the sampling values from the first sampling value, and the added value exceeds a first threshold value. An ultrasonic human body sensor that determines that a human body is present in the monitoring space.   The determination means determines that there is a human body at or near the position in the monitoring space corresponding to the sampling timing of the sampling value when the added value exceeds the first threshold, and the position information The ultrasonic human body sensor according to claim 1, wherein the ultrasonic human body sensor is stored in a storage unit.   Even if the addition value exceeds the first threshold value, the determination means has a position in the monitoring space corresponding to the sampling timing of the sampling value when the first threshold value is exceeded. 3. The ultrasonic wave according to claim 2, wherein when the position information is determined to be a position that is a predetermined distance or more than the position information already stored in the storage device, the update of the position information stored in the storage means is not stored. Human body sensor.   When the difference between the sampling values before and after the sampling value when the addition value exceeds the first threshold is less than the second threshold, even if the addition value exceeds the first threshold, The determination that the human body is present at or near the position in the monitoring space corresponding to the sampling timing of the sampling value when the first threshold value is exceeded is not performed. The ultrasonic human body sensor described in 1.   The ultrasonic human body sensor according to claim 1, wherein the determination unit can change a range of the monitoring space.   A toilet apparatus comprising the ultrasonic human body sensor according to any one of claims 1 to 5. A human body detection method for intermittently transmitting an ultrasonic wave toward a monitoring space and determining the presence or absence of a human body using an ultrasonic transmission / reception unit that receives a reflected wave with respect to the transmission,
Each time the ultrasonic wave is transmitted intermittently by the ultrasonic wave transmitting / receiving means, the reception signal output corresponding to the reflected wave is sequentially sampled at a predetermined period and A / D converted, and a plurality of sampling values are obtained. A step of configuring received waveform data,
Of the received waveform data, storing received waveform data obtained at a timing when a human body does not exist as reference waveform data;
A comparison between the received waveform data and the reference waveform data is performed for each sampling value, a difference between the sampling values is sequentially added from the first sampling value, and when the added value exceeds a first threshold value, Determining that a human body is present in the surveillance space;
A human body detection method.

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