JP6926680B2 - Attendance detection system, presence detection device, presence detection method and program - Google Patents

Description

The present invention relates to an attendance detection system for detecting the presence of a person, an attendance detection device, an attendance detection method, and a program for causing a computer to execute an attendance detection process.

For moving objects such as automobiles and passenger planes that are accompanied by engine vibration, it detects the presence of a person to improve safety such as forgetting to fasten the seat belt and preventing accidental starting, and convenience such as searching for vacant seat information and managing seats. Has been improved.

As a method of detecting the presence of a person, a method of determining the presence or absence of a person from a camera image of the seat, and a method of determining the presence or absence of a person by using pattern recognition for a signal obtained from a piezoelectric sensor installed on the seat surface. There are known methods, a method of detecting presence by performing frequency analysis on a signal obtained from a piezoelectric sensor installed on a seat surface and detecting a signal peculiar to the human body (see, for example, Patent Document 1). ).

However, the method using a camera image has a problem that a large amount of calculation is required for image processing for detecting a person. Further, in the method using pattern recognition, it is necessary to prepare teacher data for various signal patterns in order to improve the accuracy, and there is a problem that the amount of calculation for pattern recognition increases as the teacher data increases. rice field. Further, the method of performing frequency analysis has a problem that a large amount of calculation is required for the Fourier transform for frequency analysis.

The present invention has been made in view of the above problems, and an object of the present invention is to provide a system, an apparatus, a method and a program capable of detecting the presence of a person with a small amount of calculation.

In order to solve the above-mentioned problems, in one embodiment of the invention, it is an attendance detection system that detects the presence of a person.
An extreme value detecting means that detects a plurality of extreme values from the measurement results of the measuring means that measures the change in the force applied to the seat, and
Among a plurality of extreme values detected by the extreme value detecting means, the difference value between the maximum value and the minimum value that are adjacent in time is calculated, and the difference between the maximum difference value and the minimum difference value among the calculated difference values is calculated. As a judgment value, and a calculation method
Provided is an attendance detection system including a determination means for determining whether or not a person is present or absent based on a determination value calculated by the calculation means.

According to the present invention, the presence of a person can be detected with a small amount of calculation.

The figure which showed the 1st configuration example of the presence detection system. The figure which showed the structure of the piezoelectric sensor which constitutes the presence detection system, and an example of the signal output from the piezoelectric sensor. The figure which showed an example of the signal output from the piezoelectric sensor when a person sits down and leaves a seat. The figure which showed an example of the signal output from the piezoelectric sensor when an object is put on a seat and is removed. The figure which showed an example of the signal output from the piezoelectric sensor when a person is seated and left in the seat while the engine is running, and an object is placed and removed. The figure explaining the calculation procedure of the judgment value for judging the presence or absence of a person in a seat. The figure explaining the judgment value at the time of absence in the engine operating state. The figure explaining the judgment value at the time of absence in the engine non-operating state. The figure explaining the signal output from a piezoelectric sensor, the determination value, and the determination result. The figure which compared the computational complexity for 1000 data. The figure which showed the configuration example of the information processing part provided in the presence detection system. A flowchart showing the flow of the presence detection process in the engine operating state. The figure which showed the 2nd configuration example of the presence detection system. The figure which showed the configuration example of the control part. The flowchart which showed the 1st example of the process which controls a moving body based on the presence detection result. The flowchart which showed the 2nd example of the process which controls a moving body based on the presence detection result. The figure which showed the 3rd configuration example of the presence detection system. The flowchart which showed the 3rd example of the process which controls a moving body based on the presence detection result. The figure explaining the method of preventing the misjudgment of sitting. The figure explaining the method which further reduces the calculation amount in the presence detection processing. The figure explaining the method of shortening the time required for absenteeism determination. The figure explaining the specific method for shortening the time required for absenteeism determination.

FIG. 1 is a diagram showing a first configuration example of an attendance detection system that detects the presence of a person. The presence detection system is installed on the seat surface 10a of the seat 10 for a person to sit on, and includes a sensor 11 as a measuring means for measuring a change in the force applied to the seat surface 10a. The sensor 11 may be installed so as to be exposed on the seat surface 10a, or may be installed under the seat cover or the like of the seat surface 10a.

The attendance detection system includes an attendance detection device that is connected to the sensor 11 and detects the presence of a person based on a signal from the sensor 11. In the example shown in FIG. 1, the presence detection device includes an input unit 12, a storage unit 13, and an information processing unit 14. The input unit 12 inputs the signal output from the sensor 11, and the storage unit 13 stores the signal input by the input unit 12 as the measurement result of the sensor 11. The information processing unit 14 determines whether or not a person is present in the seat 10 based on the measurement result stored in the storage unit 13.

The input unit 12 includes an input / output I / F and a network I / F, and is connected to the sensor 11 by a cable or the like. When the sensor 11 is a device capable of wireless communication, the input unit 12 may be a wireless communication unit, perform wireless communication with the sensor 11, and input a signal from the sensor 11. The input unit 12 acquires the signal output from the sensor 11 as a measurement result (measurement data) at regular time intervals.

The storage unit 13 is an HDD (Hard Disk Drive), a flash memory, or the like, and stores measurement data acquired by the input unit 12 at regular time intervals. The information processing unit 14 includes a storage device such as a CPU (Central Processing Unit), a RAM (Random Access Memory), a ROM (Read Only Memory), and a flash memory, executes a program stored in the storage device, and executes the storage unit 13. It is determined whether or not a person is present in the seat 10 by using the measurement data stored in the seat 10.

The presence detection system can detect the presence in a static place such as an office, a movie theater, or a theater where vibration does not occur, but it depends on the operation of the engine of a private car, bus, railroad, passenger plane, etc. It is possible to detect the presence of a person even in a moving body that causes vibration. Although the presence detection device has been described as not including the sensor 11 in FIG. 1, the presence detection device may include the sensor 11.

As the sensor 11, the piezoelectric sensor shown in FIG. 2A can be used. The piezoelectric sensor is composed of a piezoelectric element 20 and two electrodes 21 and 22 sandwiching the piezoelectric element 20, and when a force is applied in the direction of compressing the piezoelectric element 20, a negative voltage is generated to cause the piezoelectric element 20 to be pressed. It has the characteristic that a positive voltage is generated when a force is applied in the stretching direction. That is, when a person sits on the seat surface 10a on which the piezoelectric sensor is installed, the piezoelectric element 20 is compressed, so that a negative voltage is generated. On the other hand, when a person leaves the seat, the compressed piezoelectric element 20 is stretched in an attempt to return to its original state, so that a positive voltage is generated.

The output signal of the piezoelectric sensor is represented as a change in voltage with time, as shown in FIG. 2 (b). The example shown in FIG. 2 shows an example in which the polarity of the generated voltage is positive when the electrode 21 on the upper surface is positive, and shows the opposite polarity when the electrode 22 on the lower surface is positive. The piezoelectric sensor detects a change in the force applied to the piezoelectric element 20 and generates a voltage. Therefore, when a constant force is continuously applied, for example, when an object is placed on the sensor, the voltage is applied. Does not occur.

In FIG. 2A, the piezoelectric element 20 has a peak at the point where the change in force when pushing and releasing the piezoelectric element 20 is the largest, and takes an extreme value at that peak.

With reference to FIG. 3, regarding the signal output from the sensor 11 when a person sits down and leaves the seat, with reference to FIG. 4, the signal is output from the sensor 11 when an object is placed on the seat 10 and removed. The signal to be generated will be described. Hereinafter, the sensor 11 will be described as the piezoelectric sensor shown in FIG. When a person sits on the sensor 11 installed on the seat surface 10a, as shown in FIG. 3, the piezoelectric element 20 of the sensor 11 is compressed, a negative voltage is generated as a signal, and when the person leaves the seat, the sensor 11 A positive voltage is generated as a signal by returning the compression and contraction of the piezoelectric element 20 of the above. Further, when a person stands still while seated, minute vibrations are generated on the body surface in contact with the seat surface 10a due to the heartbeat activity and the respiratory activity of the human body. Therefore, a signal synchronized with the body movement is generated.

On the other hand, when an object is placed on the seat surface 10a, as shown in FIG. 4, the piezoelectric element 20 of the sensor 11 is compressed, a negative voltage is generated as a signal, and when it is removed, the piezoelectric element of the sensor 11 is removed. When the compression of 20 returns, a positive voltage is generated as a signal. Therefore, the waveform is similar to that of a person sitting and leaving. However, as long as the state in which an object is placed on the seat surface 10a continues, a minute vibration is not generated unlike the human body, so no signal is generated.

3 and 4 show signal waveforms when a person is simply seated and left in seat 10 and an object is placed and removed. When the seat 10 is a moving body such as a vehicle or a passenger plane driven by an engine, vibration by the engine (engine vibration) is accompanied. Then, as shown in FIG. 5, positive and negative voltages are generated as signals even when a person is absent or while the state in which an object is placed continues, and the person is present only by the presence or absence of the signal. It is difficult to detect.

However, referring to FIG. 5 in detail, when a person is present, the signal has a mixture of waveforms having a large amplitude (peak) and a waveform having a small peak, whereas when a person is absent or an object is placed. In this case, it can be seen that the waveforms in which the signals have similar peaks are continuous. From this, it is possible to distinguish between the presence of a person and the absence of a person or the state in which an object is placed, depending on whether the waveform has large and small peaks or the waveforms having similar peaks are continuous. Based on, the presence or absence of a person can be determined.

A procedure for calculating a determination value for determining the presence or absence of a person on the seat 10 will be described with reference to FIG. FIG. 6A is a diagram showing an output signal from the sensor 11 and a pulsating waveform obtained by enlarging a part of the output signal. The sensor 11 outputs a signal in which positive and negative peaks are alternately continuous due to engine vibration and the presence of a person. The input unit 12 acquires the output signal at regular time intervals, and the storage unit 13 stores the acquired signal as measurement data. The storage unit 13 stores waveform data for a certain period in the past from the present time, and deletes data before the certain period in the past.

FIG. 6B is a diagram showing the maximum value and the minimum value as the extreme values of the pulsating waveforms of the signals acquired at regular time intervals by detecting the extreme values. The information processing unit 14 refers to the waveform data stored in the storage unit 13 and detects an extreme value from this waveform. The extreme value is the voltage value of the peak of the pulsation waveform, the maximum value is the voltage value of the positive peak, and the minimum value is the voltage value of the negative peak. The extremum can be detected as a voltage value when, for example, a function that approximates the waveform is obtained, the function is differentiated to obtain the derivative, and the derivative becomes 0. This method is an example and is not limited to this method.

FIG. 6C is a diagram showing a method of calculating the difference value between the maximal values that are adjacent in time among the detected extreme values. In the pulsation waveform, positive and negative peaks are alternately continuous, so the maximum values that are adjacent in time are the voltage value of a certain positive peak (first voltage value) and immediately before or after the positive peak. Indicates the voltage value (second voltage value) of the positive peak one before or one after the negative peak in. The difference value between the maximum values is a value obtained as the difference between the first voltage value and the second voltage value.

FIG. 6D is a diagram showing a method of calculating the difference value between the minimum values that are adjacent in time among the detected extreme values. The temporally adjacent minimum values are the voltage value of a certain negative peak (third voltage value) and the negative one immediately before or one after the positive peak immediately before or after the negative peak. The peak voltage value (fourth voltage value) of. The difference value between the minimum values is a value obtained as the difference between the third voltage value and the fourth voltage value. In this way, the difference between all adjacent maxima and minima is calculated.

FIG. 6E is a diagram showing a method of calculating a determination value used for determining presence from the calculated difference value. Extract the maximum difference value and the minimum difference value from the calculated difference value. Then, as shown in FIG. 6 (f), the difference between the extracted maximum difference value and the minimum difference value is calculated as a determination value. When a waveform with a large peak and a waveform with a small peak are mixed in the pulsation waveform, the determination value becomes a large value.

FIG. 7 is a diagram showing a method of calculating the difference value between the maximum value and the minimum value when an object is placed on the seat 10 or when the vehicle is absent under engine vibration. Further, FIG. 8 is a diagram showing a method of calculating the difference value between the maximum value and the minimum value when the engine is not operating and is absent. In each case, since the waveforms having the same peaks are continuous, the difference value between the maximum values and the difference value between the minimum values are small values. Therefore, even if the maximum difference value and the minimum difference value are extracted and the difference between the extracted maximum difference value and the minimum difference value is calculated as a judgment value, the calculated judgment value is a small value.

It should be noted that the waveforms having the same peaks are continuous when the object is placed on the seat 10 and when the object is placed under the engine vibration, but the object placed on the seat surface 10a resonates with the engine vibration. Since it vibrates in synchronization with the engine vibration cycle, the waveform has a large peak as shown in FIG. Further, the closer the resonance frequency depending on the mass of the object and the frequency of the engine vibration are, the larger the peak becomes.

When a mixture of large and small waveforms indicates that a person is present, it can be determined whether or not a person is present in the seat 10 depending on whether or not the determination value is large. As shown in FIG. 9, whether or not the determination value is a large value can be determined by providing a threshold value EPth and determining whether or not the determination value is equal to or greater than the threshold value EPth.

The determination based on the determination value may determine whether or not the patient is present based on the determination value for a certain period in the past. For example, a method of determining absent when the determination value is continuously below the threshold EPth for a certain period of time, or when there is a certain percentage or more of the determination values within the past fixed period that are equal to or greater than the threshold EPth. A method of determining presence can be used.

FIG. 10 shows the amount of calculation when the judgment value is calculated for the data of 1000 points in the past and the amount of calculation when the frequency analysis by the conventional fast Fourier transform (FFT) is performed on the same data. It is a figure. From the results shown in FIG. 10, it can be seen that the method using the determination value requires less calculation than the method using the conventional FFT. Therefore, in the method using the judgment value, the judgment can be performed at the same speed as the method using the FFT even if a machine with low specifications is used, and as a result, the cost of the system can be suppressed. ..

FIG. 11 is a diagram showing a configuration of an information processing unit 14 for realizing the above processing. The information processing unit 14 includes at least an extreme value detection unit 30, a calculation unit 31, and a determination unit 32. The extreme value detection unit 30 detects a plurality of extreme values from the measurement results of the sensor 11 that measures the change in the force applied to the seat, which is stored in the storage unit 13. Extreme values include both maximum and minimum values.

The calculation unit 31 calculates the difference value between the maximum values and the minimum values that are adjacent in time among the plurality of extreme values detected by the extreme value detection unit 30. Then, the calculation unit 31 extracts the maximum difference value and the minimum difference value among the calculated difference values, calculates the difference between the extracted maximum difference value and the minimum difference value, and determines the calculated difference value. Output as.

The determination unit 32 refers to the measurement result stored in the storage unit 13 based on the determination value output by the calculation unit 31, and determines whether or not the person is present or absent at each time. The determination unit 32 uses the threshold EPth to determine whether or not the determination value is equal to or greater than the threshold EPth. Determined to be absent. Here, the configuration of the information processing unit 14 as one unit including the extremum detection unit 30, the calculation unit 31, and the determination unit 32 is illustrated, but the present invention is not limited to this, and each unit is separated and separate. It may be configured as a unit.

FIG. 12 is a flowchart showing the flow of the presence detection process in the engine operating state. The presence detection process starts from step 1200, and in step 1205, the input unit 12 acquires the measurement data from the sensor 11 installed on the seat surface 10a at regular time intervals, for example, every 1 ms. Here, it is set every 1 ms, but it may be every 0.5 ms, every 2 ms, or the like. In step 1210, the acquired measurement data is stored in a predetermined storage area M of the storage unit 13.

In step 1215, the information processing unit 14 confirms whether or not the number of data stored in the storage area M is a certain number (n) or more. The number of data can be set in advance according to how much the past data is used in the calculation of the determination value, and can be, for example, 1000. When the number of data is large, the accuracy of presence determination is improved, but the responsiveness is lowered. On the contrary, when the number of data is small, the accuracy of the presence determination is lowered, but the responsiveness is improved. If the number is less than n, the process returns to step 1205.

If there are n or more, the process proceeds to step 1220, and the data is deleted from the beginning of the storage area M, that is, the oldest data so that the number of data stored in the storage area M is n. Therefore, the presence detection device can be provided with a processing unit that performs a predetermined process such as deleting the data in the storage unit 13. When the number of data is n after the deletion, in step 1225, the extremum detection unit 30 detects the extremum from the n data.

In step 1230, the calculation unit 31 calculates the difference value between the maximum values and the minimum values that are adjacent in time among the detected extreme values. Then, in step 1235, the calculation unit 31 extracts the maximum difference value and the minimum difference value from the calculated difference values, and calculates the difference between the extracted maximum difference value and the minimum difference value. The calculation unit 31 outputs the calculated difference as a determination value.

In step 1240, the determination unit 32 compares the determination value with the threshold EPth and determines whether the determination value is equal to or greater than the threshold EPth. If it is equal to or higher than the threshold value EPth, the process proceeds to step 1245, and it is determined that the user is present. On the other hand, if it is less than the threshold value EPth, the process proceeds to step 1250, and it is determined that the user is absent. When these determinations are completed, the process proceeds to step 1255 to end the presence detection process.

The presence detection system may only perform the presence detection shown in FIG. 1, but has an additional function such as controlling the moving body 1 having a seat based on the presence detection result. There may be. FIG. 13 is a diagram showing a second configuration example of an attendance detection system that detects the presence of a person. In the example shown in FIG. 12, the presence detection device includes an information acquisition unit 15 and an instruction unit 16 in addition to the input unit 12, the storage unit 13, and the information processing unit 14. Since the input unit 12, the storage unit 13, and the information processing unit 14 have already been described, only the information acquisition unit 15 and the instruction unit 16 will be described here.

The information acquisition unit 15 acquires information (mobile body information) regarding the moving body 1 such as the operating state of the engine mounted on the moving body 1, the state of the accelerator and the side brake, and the temperature inside the vehicle. The moving body 1 is equipped with a control unit (control unit) for controlling the engine ON / OFF, accelerator, side brake, air conditioner for adjusting the temperature inside the vehicle, etc., and the information acquisition unit 15 is a control unit. Can communicate with and acquire mobile information.

The instruction unit 16 instructs the control unit to perform control such as applying the brake, sounding the horn, turning on the light, raising the room temperature, and lowering the room temperature. The instruction unit 16 refers to the moving body information acquired by the information acquisition unit 15, and gives an instruction to the control unit based on the determination result of the determination unit 32.

The instruction unit 16 applies the brake when, for example, the presence detection result of the determination unit 32 is absent and the side brake information, which is one of the moving object information acquired by the information acquisition unit 15, is OFF. To prevent accidental starting. In addition, the instruction unit 16 can instruct the passengers outside the vehicle to sound the horn, turn on the light, or both, and notify the passenger outside the vehicle that he / she has forgotten to apply the side brake.

When the accelerator information, which is one of the moving body information, is information indicating that the accelerator is being stepped on, the instruction unit 16 does not stop the traveling of the moving body 1 even if the presence detection result is absent. Can be instructed. As a result, even if the determination unit 32 mistakenly determines that the moving body is absent while the occupant is traveling, the traveling can be continued and the occupant's safety can be ensured.

Here, it has been described that the presence detection system does not have a control unit, but a system including the control unit may be used as the presence detection system. When the presence detection system includes a control unit, the control unit can make a judgment based on the determination result and perform control such as sounding the horn without receiving an instruction from the instruction unit 16. Therefore, when the presence detection system includes a control unit, the presence detection system does not have to include the instruction unit 16.

Here, with reference to FIG. 14, the control unit 40 included in the moving body 1 will be briefly described. The control unit 40 is composed of a plurality of vehicle control computers called ECUs (Electronic Control Units), and the plurality of ECUs form an in-vehicle network called CAN (Controller Area Network) so that they can communicate with each other. It has become.

Examples of the plurality of ECUs include an ECU 41 for vehicle body control, an ECU 42 for collecting engine information, an ECU 43 for collecting temperature information, an ECU 44 for collecting brake information, and an ECU 45 for collecting accelerator information. An engine information acquisition sensor 46 for acquiring engine information is connected to the engine information collecting ECU 42. As engine information, the number of revolutions of the engine and the like can be mentioned. A temperature information acquisition sensor 47 for measuring the temperature inside the vehicle is connected to the temperature information collecting ECU 43.

A brake information acquisition sensor 48 for acquiring information such as ON / OFF of the side brake is connected to the brake information collecting ECU 44. An accelerator information acquisition sensor 49 for acquiring information on whether or how much the accelerator is being depressed is connected to the accelerator information collecting ECU 45.

The vehicle body control ECU 41 is connected to the engine information collecting ECU 42, the temperature information collecting ECU 43, the brake information collecting ECU 44, and the accelerator information collecting ECU 45, and provides the information acquired by each ECU to the presence detection system. When the presence detection system includes the control unit 40, the vehicle body control ECU 41 receives an acquisition request from the information acquisition unit 15, instructs each ECU to collect each information, and acquires the information from each ECU. Each information is transmitted to the information acquisition unit 15.

With reference to FIG. 15, the false start prevention control executed by the presence detection system shown in FIG. 13 will be described. The control is started from step 1500, and in step 1505, the instruction unit 16 confirms whether or not the presence detection result of the driver's seat is absent. If he / she is present, there is no risk of erroneous start, so the process proceeds to step 1525 and the erroneous start prevention control is terminated. If the driver is absent, the process proceeds to step 1510, and the information acquisition unit 15 acquires side brake information from the control unit 40.

In step 1515, the indicator unit 16 refers to the side brake information and confirms whether or not the side brake state is OFF. When the state is ON and the side brake is applied, there is no risk of erroneous starting, so the process proceeds to step 1525 and this control is terminated. When the state is OFF, the process proceeds to step 1520, and the instruction unit 16 instructs the control unit 40 to apply the side brake. Upon receiving the side brake applied by the control unit 40, the process proceeds to step 1525 to end the erroneous start prevention control. It should be noted that this control can be performed again after a certain period of time has elapsed from the end of the control in step 1525.

Next, with reference to FIG. 16, the indoor temperature control of the moving body 1 executed by the presence detection system shown in FIG. 13 will be described. Control is started from step 1600, and in step 1605, the instruction unit 16 confirms whether or not the presence detection results for all the seats in the vehicle are absent. When even one person is present, the passenger can adjust the temperature in the room by himself / herself, so that the process proceeds to step 1625 and the room temperature control is completed. If the person is absent, the process proceeds to step 1610, and the information acquisition unit 15 acquires the room temperature information.

In step 1615, the indicator 16 refers to the room temperature information and confirms whether the room temperature is lower than the preset minimum temperature TLow or higher than the maximum temperature THigh. When the room temperature is TLow or more and THigh or less, it is assumed that the temperature control does not need to be performed, and the process proceeds to step 1625 to end the room temperature control. If the room temperature is lower than TLow, or if the room temperature is higher than THigh, it is necessary to perform temperature control. Therefore, the process proceeds to step 1620, and the instruction unit 16 raises the room temperature or raises the room temperature with respect to the control unit 40. Instruct to lower.

Upon receiving that the control unit 40 adjusts the temperature in the room and the room temperature is within the range of TLow or more and THigh or less, the process proceeds to step 1625 and the room temperature control is terminated. Similar to the false start prevention control, this control can be re-executed after a certain period of time has elapsed from the end of the control in step 1625. Adjusting the temperature inside the vehicle does not directly affect safety and can be carried out as needed.

FIG. 17 is a diagram showing a third configuration example of an attendance detection system that detects the presence of a person. In the example shown in FIG. 17, the presence detection device includes a biological information detection unit 17 in addition to the input unit 12, the storage unit 13, the information processing unit 14, the information acquisition unit 15, and the instruction unit 16. Since the input unit 12, the storage unit 13, the information processing unit 14, the information acquisition unit 15, and the instruction unit 16 have already been described, only the biological information detection unit 17 will be described here.

The biometric information detection unit 17 detects biometric information for discriminating the occupant. In this example, it is determined whether the passenger is an infant or a non-infant, and when the passenger is only an infant, the outside of the moving body 1 is notified in order to prevent the passenger from being left behind in the vehicle in the summer or winter. Explain as a thing.

The biological information may be any information as long as it can determine whether or not the child is an infant, and examples thereof include a pulse rate. The pulse rate changes with adulthood and is about 60 to 90 times / minute in adults, whereas it is 100 to 140 times / minute in infants and 80 to 110 times / minute in infants, which is higher than that in adults. From this, for example, 100 times / minute is used as a reference value, and if it is 100 times / minute or more, it can be determined to be an infant, and if it is less than 100 times / minute, it can be determined to be a non-infant.

The biological information detection unit 17 uses waveform data having large and small peaks stored in the storage unit 13 when the presence detection result is present, and the pulse rate is calculated from the number of waveforms having a large amplitude within a certain period of time. Can be calculated. The information processing unit 14 includes a discriminating unit that discriminates the occupant based on the pulse rate calculated by the biological information detection unit 17, and can determine whether or not the occupant is an infant.

When the presence detection result is present, the in-vehicle temperature information acquired by the information acquisition unit 15 indicates that the temperature inside the vehicle is out of a certain temperature range, and only infants are in the vehicle, the instruction unit 16 informs the control unit 40. Instruct them to honk, turn on the light, or both. As a result, it is possible to notify a person outside the vehicle and prevent a fatal accident due to the abandonment of an infant. In addition, when the pulse rate calculated by the biometric information detection unit 17 is 100 times / minute or more continuously for a certain period of time in all the seats determined to be present, the discriminating unit is an infant in the vehicle. Determine as only.

As a method of notifying people outside the vehicle, in addition to sounding the above horn and turning on the light, displaying characters on the display installed on the vehicle body, and projecting information on windows such as the windshield. The method of doing this can be mentioned. Further, when a child rides, a child seat or a baby seat may be used, but by attaching the sensor 11 to the seat surface of the child seat or the like, it is possible to detect the presence of the infant as well.

With reference to FIG. 18, the infant abandonment prevention control executed by the presence detection system shown in FIG. 17 will be described. The control is started from step 1800, and in step 1805, the instruction unit 16 confirms whether or not even one person is present as the presence detection result. If absent, the process proceeds to step 1845 to end the abandonment prevention control. When present, the process proceeds to step 1810, and the information acquisition unit 15 acquires the temperature information inside the vehicle.

In step 1815, the indicator 16 refers to the vehicle interior temperature information and confirms whether the vehicle interior temperature is lower than the preset minimum temperature TLow or higher than the maximum temperature THigh. When the temperature inside the vehicle is within the range of TLow or more and THigh or less, it is assumed that the temperature control does not need to be performed, and the process proceeds to step 1845 to end the abandonment prevention control. If the temperature inside the vehicle is lower than TLow, or if the temperature inside the vehicle is higher than THigh, the process proceeds to step 1820, and the biometric information detection unit 17 obtains data acquired from sensors 11 installed in all seats determined to be present. Use to calculate the pulse rate. Then, in step 1825, the biological information detection unit 17 stores the detected pulse rate in the storage unit 13.

In step 1830, the indicator 16 confirms whether the pulse rate has been continuously stored for a certain period of time, for example, m minutes or more. The period m is the time for the passenger to continuously detect the pulsation in order to determine that the child is an infant, and it is considered that the pulse rate does not remain elevated for more than 5 minutes while driving for an adult. Therefore, for example, it can be set to 5 minutes. If it is not stored, the process returns to step 1820, and if it is stored, the process proceeds to step 1835.

In step 1835, the indicator 16 confirms whether the stored pulse rate is continuously equal to or greater than the reference value p for m or more. The reference value p of the pulse rate is a pulse rate for determining the passenger as an infant, and can be, for example, 100 times / minute. If all of the pulse rates are above the reference value p, all present are determined to be infants, proceed to step 1840, and if even one of the pulse rates is below the reference value p, the passenger is an adult. Therefore, the process proceeds to step 1845 to end the abandonment prevention control.

In step 1840, the instruction unit 16 instructs the control unit 40 to sound the horn and turn on the light. The control unit 40 receives an instruction from the instruction unit 16 to sound the horn and turn on the light. As a result, after notifying the person outside the vehicle, the abandonment prevention control is terminated in step 1845. This control can also be performed again after a certain period of time has elapsed from the end of the control in step 1845.

The presence detection system instructs the vehicle body control ECU 41 to sound the horn, turn on the light, apply the side brake, raise the vehicle interior temperature, decrease the vehicle interior temperature, etc., and the vehicle body control ECU 41 gives the instruction. In response, it executes processing such as ringing the horn. When the control unit 40 is included in the presence detection system, the control unit 40 provides the information acquired by each ECU to the presence detection device in the system, and receives an instruction from the presence detection device to turn on the horn. It is possible to execute processing such as ringing.

The determination unit 32 determines that the user is present when the determination value is equal to or greater than the threshold EPth, but the determination value may be equal to or greater than the threshold EPth even when he / she is not actually present. For example, when the door of the moving body is closed when the moving body is absent, or when the hand lightly touches the seat surface 10a. In such a case, if it is determined that the person is present, the determination will be erroneous, and it is necessary to prevent this. Therefore, a seating determination threshold EPs is provided separately from the threshold EPth, and it is determined that the person is present only when the determination value becomes equal to or greater than the seating determination threshold EPs.

When the output from the sensor 11 is represented by the waveform shown in FIG. 19 (a), as shown in FIG. 19 (b), there is a portion where the threshold EPth alone exceeds the threshold EPth even when absent. , It will be judged as being present. However, by providing the seating determination threshold EPs which are higher than the threshold EPth, it is possible to appropriately determine the absence even when the person is absent. This is based on the fact that a large impact is applied to the piezoelectric sensor at the time of sitting, and the judgment value at the moment of sitting becomes large.

The information processing unit 14 of the attendance detection system can always execute the attendance detection process, but if it is possible to determine whether or not to leave the seat in addition to the above-mentioned seating determination, the person is present during that time. Since it is clear, the presence detection process during that period can be stopped. As a result, the processing performed by the information processing unit 14 can be reduced, and the amount of calculation in the system can be reduced.

When leaving the seat, a large impact is applied to the piezoelectric sensor, so that a large positive voltage is generated. Therefore, as in the case of sitting down, the leaving seat can be determined by providing the leaving seat determination threshold value VL as shown in FIG. 20 (a). Therefore, the information processing unit 14 can stop the presence detection process until the voltage of the measurement data becomes equal to or higher than the departure determination threshold value VL after once determining the presence.

However, even in actions such as shaking the body while sitting or shifting the sitting position, a large impact similar to that when leaving the seat is given to the piezoelectric sensor. Therefore, as shown in FIG. 20 (b), when the voltage of the measurement data becomes equal to or higher than the vacancy determination threshold value VL, the presence detection process is restarted, and only while the voltage becomes VL or higher and a certain period of time elapses. The judgment value can be calculated and the presence detection can be performed. This is because it is possible to determine whether the person is present or absent by calculating the determination value and detecting the presence of the person while a certain period of time elapses. Since it is not known when to be seated while absent, the presence detection process is executed.

The seat surface 10a of the seat 10 may be made of a hard material or a soft material. The hard material has a small sinking when seated, and the piezoelectric element of the sensor 11 is compressed and contracted relatively quickly after leaving the seat. .. On the other hand, the soft material has a large sinking when seated, and the piezoelectric element is gradually compressed and contracted. Then, as shown in FIG. 21A, the voltage output by the sensor 11 gradually decreases, and it takes a certain amount of time until the voltage becomes zero.

In the period when the voltage gradually decreases, the calculated judgment value becomes a relatively large value, and does not fall below the threshold value EPth until the voltage converges to near 0. In this case, as shown in FIG. 21B, it takes time to determine that the person is absent.

The output of the sensor 11 installed on the seat surface 10a made of a soft material contains a bias component that moderates the change in the output. The bias component is a voltage component as shown in FIG. 22 (a), and by removing this, the voltage as shown in FIG. 22 (b) quickly decreases to near 0, and the time required for absentee determination is shortened. can do. The removal of this bias component can also be performed by the processing unit described above.

As a method for calculating the bias component, for example, a least squares method (regression analysis), a principal component analysis, a weighted least squares method, or the like can be used. These methods are well-known statistical methods and are not described in detail here.

As described above, the extreme value is detected from the output waveform of the sensor 11, the difference value between the adjacent maximum value and the minimum value is calculated, and the difference between the maximum difference value and the minimum difference value is used as a determination value. Since it is calculated and the presence detection is performed based on whether or not the determination value is equal to or greater than the threshold value, the presence detection can be performed with a smaller amount of calculation as compared with the conventional method using frequency analysis or the like.

By controlling the moving body using the presence detection result, it is possible to realize prevention of erroneous starting, temperature adjustment in the vehicle, notification for preventing infants from being left behind in the vehicle, and the like. Further, even if noise such as touching the seat surface is generated, the presence detection can be performed without erroneous determination. Further, it is possible to reduce the presence detection process while the seat is present, and it is possible to make an appropriate determination according to the material of the seat surface.

So far, the present invention has been described with the above-described embodiments as a presence detection system, a presence detection device, a presence detection method, and a program. However, the present invention is not limited to the above-described embodiment, and can be modified within the range conceivable by those skilled in the art, such as other embodiments, additions, changes, and deletions. .. Further, any aspect is included in the scope of the present invention as long as the action / effect of the present invention is exhibited. Therefore, it is possible to provide a recording medium on which the program is recorded, a program providing server that provides the program, and the like.

1 ... Moving body 10 ... Seat 10a ... Seat surface 11 ... Sensor 12 ... Input unit 13 ... Storage unit 14 ... Information processing unit 15 ... Information acquisition unit 16 ... Indicator 17 ... Biometric information detection unit 20 ... Piezoelectric elements 21, 22 ... Electrode 30 ... Extreme value detection unit 31 ... Calculation unit 32 ... Judgment unit 40 ... Control unit 41 ... ECU for vehicle body control
42 ... ECU for collecting engine information
43 ... ECU for collecting temperature information
44 ... ECU for collecting brake information
45 ... ECU for collecting accelerator information
46 ... Engine information acquisition sensor 47 ... Temperature information acquisition sensor 48 ... Brake information acquisition sensor 49 ... Accelerator information acquisition sensor

Japanese Patent No. 3012751

Claims (11)

It is an attendance detection system that detects the presence of a person.
An extreme value detecting means that detects a plurality of extreme values from the measurement results of the measuring means that measures the change in the force applied to the seat, and
Among the plurality of extreme values detected by the extreme value detecting means, the difference values between the temporally adjacent maximum values and the minimum values are calculated, and the maximum difference value and the minimum difference value among the calculated difference values are calculated. A calculation method that calculates the difference between values as a judgment value,
The present invention includes a determination means for determining absence until the determination value calculated by the calculation means becomes equal to or higher than the first threshold value, and determining presence when the determination value becomes equal to or higher than the first threshold value. Attendance detection system. An acquisition means for acquiring mobile information about the moving body from a control means for controlling the moving body having a seat, and
The present invention according to claim 1, further comprising an instruction means for instructing the control means to control the moving body based on the moving body information acquired by the acquisition means and the determination result of the determination means. Seat detection system. The acquisition means acquires information on the traveling of the moving body as the moving body information, and obtains information about the traveling of the moving body.
When the instructing means is determined to be absent by the determination means and the moving body can travel in the information regarding the traveling of the moving body acquired by the acquisition means, the moving body cannot travel. The presence detection system according to claim 2, wherein the attendance detection system is instructed to do so. The acquisition means acquires temperature information in the moving body as the moving body information, and obtains the temperature information in the moving body.
When the indicating means is determined to be present by the determining means and the temperature inside the moving body is outside a certain range in the temperature information acquired by the acquiring means, the temperature inside the moving body is set to the temperature inside the moving body. The presence detection system according to claim 2 or 3, which instructs the temperature to be adjusted within a certain range. Biological information detecting means for detecting biological information from the measurement results of the measuring means, and
Including a discriminating means for discriminating a occupant riding on a moving body based on the detection result of the biological information detecting means.
The present invention according to any one of claims 2 to 4, wherein the instruction means instructs the control means to notify a person outside the moving body according to the determination result of the determination means. Seat detection system. The presence detection system according to any one of claims 2 to 5, further comprising a measuring means for measuring a change in a force applied on the seat and a control means for controlling a moving body having the seat. .. After determining that the determination means is present, the determination means stops the process of determining whether the person is present or absent, and when the measurement result of the measuring means becomes equal to or higher than the second threshold value, the determination means determines whether the person is present or absent. The presence detection system according to any one of claims 1 to 6 , which restarts the process of performing. A processing means for executing a predetermined process on the measurement result of the measuring means is included.
The presence detection system according to any one of claims 1 to 7 , wherein the extreme value detecting means detects the plurality of extreme values from the measurement result processed by the processing means. It is an attendance detection device that detects the presence of a person.
An extreme value detecting means that detects a plurality of extreme values from the measurement results of the measuring means that measures the change in the force applied to the seat, and
Among the plurality of extreme values detected by the extreme value detecting means, the difference values between the temporally adjacent maximum values and the minimum values are calculated, and the maximum difference value and the minimum difference value among the calculated difference values are calculated. A calculation method that calculates the difference between values as a judgment value,
It includes a determination means for determining absence until the determination value calculated by the calculation means becomes equal to or higher than the first threshold value, and determining presence when the determination value becomes equal to or higher than the first threshold value. Attendance detection device. It is a presence detection method that detects the presence of a person.
A step of detecting multiple extreme values from the measurement results of a measuring means that measures the change in force applied to the seat, and
Among the plurality of detected extreme values, the difference value between the maximum value and the minimum value that are adjacent in time is calculated, and the difference between the maximum difference value and the minimum difference value among the calculated difference values is determined. And the steps to calculate as
A presence detection method including a step of determining absenteeism until the calculated determination value becomes equal to or higher than a first threshold value, and determining presence when the determination value becomes equal to or higher than the first threshold value. A program that causes a computer to execute a process to detect the presence of a person.
A step of detecting multiple extreme values from the measurement results of a measuring means that measures the change in force applied to the seat, and
Among the plurality of detected extreme values, the difference value between the maximum value and the minimum value that are adjacent in time is calculated, and the difference between the maximum difference value and the minimum difference value among the calculated difference values is determined. And the steps to calculate as
A program for executing a step of determining absenteeism until the calculated determination value becomes equal to or higher than the first threshold value, and determining that the patient is present when the determination value becomes equal to or higher than the first threshold value.

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