JPS6215129A - Detecting device for condition of driving car asleep - Google Patents

Abstract

PURPOSE:To prevent a driver effectively from driving a car asleep by configurating a device in such a way that, when the number of detected signals from the plural number of pulse sensors all exceeds the specified level in strength, and a means is provided so as to pick up an effective one out of the said signals. CONSTITUTION:In order to select two of optimum pulse sensors 11, by which driver's pulse can be picked up, out of the plural number of pulse sensors 11 arranged on a steering wheel, signals detected by each of these sensors are inputted in order through a multi-plexer 45, and analogue switch SW, and a converter 47. When the condition of driving a car asleep is detected, two of the analogue switches selected out of analogue switches SW1 through SW16 are turned on, and amplified detected signals are inputted through a converter 49. This configuration allows only an effective pulse signal of the driver to be detected enabling the condition of driving the car asleep to be detected with high accuracy.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention detects the pulse of a vehicle driver using a pulse sensor consisting of a pair of light emitting and light receiving members, and detects drowsy driving based on changes in the pulse. This invention relates to a driving detection device.

[Prior Art] In order to prevent accidents caused by drowsiness of a vehicle driver, various drowsy driving detection devices for detecting drowsiness of a vehicle driver have been devised.
As described in Japanese Patent Application Laid-open No. 22537 and Japanese Patent Application Laid-Open No. 120133/1987, there is a method that detects the pulse of a vehicle driver using a pair of projecting/receiving members and detects dozing based on changes in the pulse. . This is because, as shown in Figure 2, the translucency of blood is different when blood is flowing and when it is stopped.
As shown in FIG. 3, a pair of pulse sensors consisting of a light emitting member 1 that emits light of a predetermined wavelength and a light receiving member 3 that receives the light are used to detect the intensity of the light that hits the bone 7 through the blood vessel 5 and is reflected. The idea is to detect the pulse from the periodic changes and detect dozing off.

[Problems to be Solved by the Invention] As described in the above-mentioned publications, the pulse sensor is usually installed directly in the hand of the vehicle driver or on the steering wheel. If the vehicle driver moves his/her hand and compresses a blood vessel, or if a shock is applied to the pulse sensor itself, the detection signal output from the pulse sensor may be disrupted, making it difficult to detect the pulse properly.

That is, as shown in FIG. 4, the pulse signal output from the pulse sensor constantly changes according to the heartbeat of the vehicle driver, as shown by the solid line, and the pulse can be detected satisfactorily. When the driver of the vehicle applies force to his/her hand, noise as shown by the broken line is generated, causing a problem in which accurate pulse detection cannot be performed.

Therefore, the present invention has been made with the object of accurately detecting the pulse rate that changes depending on the heartbeat of a vehicle driver by using a plurality of pulse sensors, and thereby making it possible to effectively prevent drowsy driving. Therefore, I adopted the following configuration.

[Means for Solving the Problems] That is, the configuration of the present invention as a means for solving the above problems includes a pair of light projecting/receiving members M1. When the plurality of pulse sensors M3 that detect pulses from the hands of the vehicle driver and the plurality of detection signals outputted from each of the pulse sensors M3 are both at a predetermined level or higher, the detection signals are determined as valid pulses. a pulse signal extraction means M4 for extracting the pulse signal as a signal; a pulse data creation means M5 for creating a pulse data of the vehicle driver based on the pulse signal extracted by the pulse signal extraction means M4; The gist of the present invention is a drowsy driving detection device comprising: drowsiness detection means M6 for detecting drowsiness of a vehicle driver by comparing pulse data set in advance with reference pulse data set in advance.

Here, the pulse sensor M3 is composed of a light projecting member M1 and a light receiving member M2, similar to the conventional sensor shown in FIG.
It detects the intensity of reflected light reflected from bones through blood vessels, and as shown in Figure 2, the pulse of the light emitted from the light projecting member M1 can be clearly distinguished between when the blood is flowing and when it is braking. It is desirable to use a wavelength of 600 nm or more. Further, an LED that emits light of a predetermined wavelength can be used as the light projecting member M1, and a phototransistor that can receive the light and output a detection signal according to its intensity can be used as the light receiving member M2. In this case, by using a plurality of phototransistors in parallel, a large detection signal can be obtained.

Further, a plurality of pulse sensors M3 (at least two or more) are provided, and the pulse signal extraction means M4 validates the detection signals when the plurality of detection signals outputted from each pulse sensor M3 are both at a predetermined level or higher. This is to extract only a valid pulse signal even if the detection signal output from each pulse sensor M3 contains noise as shown in Fig. 4. .

That is, for example, if two pulse sensors M3 are provided on the left and right hands, effective detection signals generated in response to heartbeats will be generated simultaneously from the left and right pulse sensors M3, but noise etc. will differ for each sensor. Therefore, only valid detection signals generated simultaneously from each pulse sensor are extracted as pulse signals.

Next, the pulse data creating means M5 creates pulse data of the vehicle driver based on the valid pulse signal extracted by the pulse signal extracting means M4. The peak interval (pulse interval) of each pulse signal is measured multiple times, and the average pulse interval is determined from the timing results.

The pulse rate, variance, etc. may be configured to be calculated as pulse data.

Furthermore, the drowsiness detection means M6 compares the various kinds of pulse data created above with preset reference pulse data to detect drowsiness of the vehicle driver.
In this case, drowsiness may be detected simply from pulse data alone, but by configuring this detection operation to be carried out only when the vehicle speed is equal to or higher than a predetermined speed, the accuracy of detecting drowsy driving can be improved. In other words, it is thought that vehicle drivers do not fall asleep while driving at low speeds, but drowsiness occurs when the vehicle is running stably at a predetermined speed or higher. By not performing the detection operation, it is possible to prevent false detection under the operating conditions.

[Function] In the drowsy driving detection device of the present invention configured as described above, when the detection signals output from the plurality of pulse sensors are both equal to or higher than a predetermined level, the detection signal is extracted as a pulse signal, and the drowsy driving detection device detects the drowsy driving. will be detected. Therefore, even if, for example, the driver moves his hands and generates noise from the pulse sensor, that noise will be removed, and drowsy driving detection will be performed using only valid pulse signals that correspond to the vehicle driver's heartbeat. It is possible to improve the accuracy of detecting dozing.

[Example] An embodiment of the present invention will be described below with reference to the drawings.

FIG. 5 is a block diagram showing the overall configuration of a drowsy driving alarm system that detects drowsy driving by a vehicle driver when the vehicle is traveling at a predetermined speed or higher, and issues a warning to the vehicle driver with an alarm buzzer. be. In this embodiment, 16 pulse sensors are installed on the steering wheel, and the two most effective sensors for detecting the pulse of the vehicle driver are extracted from among them, and these sensors are used to detect drowsy driving. is configured to run.

In the figure, reference numeral 11 represents 16 pulse sensors distributed on the wheel ring 15 of the steering wheel 13, as shown in FIG. , an LED 7 that emits infrared light with a wavelength of 920 [nm], four phototransistor boards 9a to 19d that receive the light and output a detection signal according to the intensity of the light, and are provided in each of these parts. , optical filters 21a to 2 that cut off light incident from the outside.
1e, and terminals 23, 25, and 27 for inputting drive signals to the LED 7 and for taking out detection signals from the phototransistors 19a to 19d.

Next, a control circuit 29 is provided on the boss portion 31 of the steering wheel 13 shown in FIG. 6, and drives each of the pulse sensors 11 and inputs detection signals to detect drowsiness of the vehicle driver and perform alarm processing. A vehicle speed signal and battery voltage from a vehicle speed sensor 35 are input to this control circuit 29 via a slip ring 33 shown in FIG. 6 provided between the steering wheel 13 and the vehicle body.

As shown in the figure, the control circuit 29 includes a CPU 37. ROM39. RAM
41, etc., and the detection signals from each of the pulse sensors 11 are
Multiplexer 45° analog switch SWO and A/
via the D converter 47 or the amplifiers A1 to A1B,
Analog switches SW1-5W16 and A/D converter 4
It is input via 9. That is, when extracting the two optimal pulse sensors 11 capable of detecting the vehicle driver's pulse from the 16 pulse sensors 11, each pulse rate is The detection signals of the sensors 11 are sequentially input, and when drowsy driving is detected, two analog switches corresponding to the extracted two pulse sensors 11 are turned on among the analog switches SW1 to SW1B, and the amplifiers (among them A1 to A16) are turned on. The detection signal amplified by two corresponding amplifiers) is input via the A/D converter 49.

The control circuit 29 also includes an oscillation circuit 51 that oscillates at IKHz, a drive circuit 53 that operates based on a signal from the oscillation circuit 51 and drives the LED 7 of each pulse sensor 1, and a microcomputer 43 that prevents the vehicle driver from falling asleep. Alarm buzzer 57 activated via buffer circuit 55 when detected
, vehicle speed sensor 3 input via slip ring 33
A buffer circuit 59 inputs the vehicle speed signal from 5 to the microcomputer 43, and a power supply circuit 61 controls the battery voltage input via the slip ring 33 to a predetermined stable voltage and applies it to each of the above parts. There is.

Furthermore, as mentioned above, the control circuit 29 is connected to the steering wheel 1.
By providing the hub portion 31 of No. 3, the wiring between the numerous pulse sensors 11 provided on the steering wheel becomes simple, and the wires will not be disconnected by the steering operation.

Next, FIG. 8 shows the electric circuit of the drive circuit 53 and pulse sensor 11. As shown in the figure, the drive circuit 53 is made up of a transistor Tr1 and a resistor R1, which are turned on and off by a control signal from the imaging circuit.
The LED 17 is driven. Then, the emitted light reflected from the bone by the emitted light is received by the photo 1 helangisters 19a to 19d, respectively, and a voltage corresponding to the intensity of the light is applied to the resistor R.
2 and is output as a detection signal to a multiplexer 45 or an amplifier.

The drowsy driving detection and warning process executed by the microcomputer 43 will be described in detail below with reference to the flowcharts shown in FIGS. 9 to 12.

First, FIG. 9 shows a pulse data calculation routine, which is a main routine that is repeatedly executed by the microcomputer 43.

As shown in the figure, when this process starts, first step 1
At step 00, initialization processing is executed to clear the values of counter flags, etc. used in the processing described later, and the process proceeds to the next step 101.
to move to. In step 101, as described above, two pulse sensors capable of detecting a pulse are selected from among the 16 pulse sensors 11.
The process of extracting each pulse sensor (hereinafter referred to as effective sensor) is executed in accordance with the flow shown in FIG. 10, which will be described later, and the process moves to the next step 102.

In step 102, in a peak detection routine for detecting the peak of the pulse signal shown in FIG. 11, which will be described later, a flag NGF, which is set when the peak of the pulse signal is not detected for a predetermined period of time or more, is reset, and in the next step 103, the flag NGF is reset. Determine whether NGF is in the set state. and N
If GF=1, go back to step 102 and extract effective sensors, while if NGF=O, step 1
04, it is then determined in the peak detection routine whether the flag F1, which is set when the peak of the pulse signal is detected, is set. Then, if F1=1, the process moves to the next step 105, and if not, the process moves to the above-mentioned step 103 again.

In step 105, it is determined whether the value of the counter i, which is incremented every time a peak of the pulse signal is detected in step 107, which will be described later, is rOJ. Moshitei=
If YES, the process moves to step 106 to clear the timer and start time measurement, and in step 107, the (direction) of the counter i is incremented, and the process returns to step 103 again.On the other hand, if i=Q, the process moves to step 108. Then, in step 108, the time Ti (pulse interval) from when the peak of the pulse signal was detected last time to when it is detected this time is read from the timer and recorded.Next, in step 109, the timer is cleared and time measurement is started again. Then, the process moves to step 110. In step 110, the above step 102 is performed.
Execute the effective sensor extraction process in the same way as in step 11.
Move to 1.

In step 111, it is determined whether the value of the counter 1 has reached 16, that is, whether the pulse intervals Ti read and recorded in step 108 have reached 16 in total, T1-T16. If the output is 16, step 107 increments 1 and steps 1
If 1=16, the process moves to the next step 112.

In step 112, the past 16 pulse signals are read and recorded every time the peak of the pulse signal is detected in step 108.
Based on the pulse intervals T1 to T, 16, the average pulse interval Ta
, the average pulse rate N, and its variance B are calculated as pulse data, and the process moves to step 113. And step 11
In step 3, the value of counter 1 is set to "1" in order to read the 16 pulse intervals T1 to T1B again from the next time, and the process moves to step 103.

Note that the average pulse interval Ta is determined in step 112 above.

When calculating the average pulse rate N and the variance B, the following equations are used.

B=Σ(Ti-Ta)2/16 Next, the effective sensor extraction process executed in step 102 or step 110 will be described with reference to the flowchart shown in FIG. 10.

This process is started after prohibiting the execution of a peak detection routine or a dozing detection routine, which will be described later, to be executed at predetermined time intervals in step 200, and first, in step 201.
At step 202, all the analog switches SWI to 5W16 are turned off, and the analog switch SWO is turned on, and the process moves to the next step 202. Then, in step 202, it is determined whether or not the LED 7 of each pulse sensor 11 is driven based on the control signal for the LED 7 output from the transmitting circuit 51, and the process is repeated until the LED 7 is driven. .

Next, when the LEDl 7 is driven, the process moves to step 203, where the detection signal Dj from the j-th pulse sensor 11 is read and recorded, and the process moves to step 204. Then, in step 204, the value of j is incremented, and in step 2
Move to 05. In step 205, it is determined whether the value of j is 17 or apricot, and if the value of j is not 17, the process returns to step 202. Here, the processing in steps 202 to 205 above represents processing for individually driving the 16 pulse sensors 11 and reading their detection signals D1 to D1B. If so, j=17, and step 206 is executed.

In step 206, the value of j is set to "1", and the process moves to the next step 207. Then, in step 207, it is determined whether or not there are two or more signals equal to or higher than a predetermined value among the 16 detection signals D1 to D16 read above. , proceed to step 208. In step 208, the analog switch corresponding to the pulse sensor that outputs the top two detection signals among the read detection signals D1 to [)16 is turned on, and the analog switch SWO@OFF is turned on, and - The process moves to step 209. In step 209, the interrupts that were prohibited in step 200 are enabled, and the processing of this routine is exited.

On the other hand, if it is determined in step 207 that there are no two or more of D1 to D1B that are equal to or greater than a predetermined value, the process moves to step 202. In this way, in step 207, r
The determination of NOJ and the transition to step 202 are made only when the process of step 102 shown in FIG. The detection signal is large and effective sensors can be extracted by one processing.

As explained above, in the pulse rate data extraction routine which is the main routine, every time the peak of the pulse signal is detected,
Although the pulse data is calculated from the pulse interval timed, the effective sensor used to detect the pulse signal is extracted every time a peak is detected, so the accuracy of the pulse data can be improved.

Next, the peak detection routine shown in FIG.
Executed every ecl to detect the peak of the pulse signal.

When the process is started, step 301 is first executed to read the time measured by the timer that has started counting in the pulse data calculation routine. Then, in step 302, it is determined whether or not the measured time T of the timer read above is 1.5 seconds or more, and if T≧1.5, the process moves to step 303. This process is a process to determine whether 1.5 seconds or more has passed since the previous peak was detected, and since the pulse interval of a human being is usually not more than 1.5 seconds, in this case, This is executed to assume that the currently used sensor is abnormal and to instruct the extraction of valid sensors again. Therefore, in step 303, the flag NGF is set to re-extract effective sensors, and in step 304, the value of i is set to rOJ,
The processing of this routine is temporarily ended.

On the other hand, if it is determined in step 302 that T<1.5, step 305 is executed, and the two effective sensors extracted in the effective sensor extraction routine of FIG. The detection signals v1 and v2 inputted are read, and the process moves to the next step 306. In step 306, it is determined whether vl and v2 are both greater than a predetermined value, and if both vl and v2 are not greater than the predetermined value, in step 307 flag F2 is reset, and this routine is temporarily terminated.

Next, in step 306, if it is determined that both Vl and v2 are greater than the predetermined value, the process moves to the next step 308, where the two detection signals 1 and V2 are added to calculate the pulse signal VO(n>, and the pulse signal VO(n>) is calculated. The process moves to step 309. In step 309, it is determined whether the flag F2 is set, that is, after both Vl and V2 are equal to or greater than a predetermined value, the process proceeds to step 309.
9 is executed for the first time. If this process is the first, since the flag F2 was reset in step 307 during the previous process, rNOJ is determined in step 309, and Stellar P31
Transition to 0.

After setting the flag F2 in step 310, the process moves to step 311, where the value of the counter C1 is incremented. Then, in the next step 312, the flag F3 is reset, and in step 313, the value of the counter C2 is cleared, and the processing of this routine is temporarily ended.

On the other hand, if rYEsJ is determined in step 309, step 314 is executed, and step 30B is performed.
The pulse signal @yO(n> obtained in step 1) is compared in magnitude with the pulse signal yo(n-1) obtained in the previous process.

Then VO(n>≧■0(n-1>, step 3
1''1- to step 313 are executed to temporarily end the processing of this routine, and conversely, VO(n) to VO(n-
1), the process moves to step 315. Note that the process in step 314 is a process for determining whether or not the pulse signal is rising, and while the pulse signal is rising, the counter C1 is repeatedly counted in step 311.

Next, in step 315, it is determined whether the flag F3 is in the reset state, and if flag F3=O, then in step 316, it is determined whether the value of the counter C2 is 1 or more. If C2 is 1, step 3~
After reading and recording the value of the counter C1 in step 17, the process moves to step 318 to clear the counter C1, and in step 319 the value of the counter C2 is incremented, and the processing of this routine is temporarily ended.

On the other hand, if it is determined in step 316 that C2≧1, then in step 320, it is determined whether the value of counter C2 is equal to or greater than a predetermined value by 2 (for example, 2).

If 02<K2, the process moves to step 319, and if C2≧2, the process moves to step 321.

Next, in step 321, the flag F3 is set, and the process proceeds to the next step 322, in which it is determined whether the value of the counter C1 is greater than or equal to a predetermined value Kl (for example, 16). If C1≧1, a flag F1 indicating peak detection is set in step 323, and if C1 is particularly 1, the process of this routine is directly terminated.

The process of the peak detection routine executed in this way is as follows:
The detection signal 1 and V2 output from the pulse sensor are both above a predetermined value, and the pulse signal VO (n > 1 continues to rise for more than a predetermined time determined by 1, and then the counter
The peak will be detected when it has fallen for a predetermined period of time determined by .

Next, FIG. 12 shows a drowsiness detection routine for detecting drowsiness of the vehicle driver from the pulse rate data obtained in the pulse rate data calculation routine, and this process is executed by an interrupt every second.

As shown in the figure, when the process starts, it is first determined in step 401 whether or not the pulse rate N is smaller than a preset reference pulse rate NS, and if N≧NS, the routine is immediately terminated. . On the other hand, if it is determined in step 401 that N<NS, the process moves to the next step 402 and the difference between the calculated pulse variance B and the reference value Bs is set to a predetermined value β.
Determine whether it exceeds. And (B-Bs)≦
If it is β, the processing of this routine is continued as it is; on the other hand, if (B-as>>β), the process moves to step 403.

In step 403, it is determined whether the traveling speed of the vehicle determined based on the signal from the vehicle speed sensor 35 is 5Qkm or more, and if it is less than 50km, the process of this routine is directly terminated, and if it is 5Qkm or more, the process proceeds to the next step. 404
to move to. Then, in step 404, the above-mentioned alarm buzzer is activated.
57 to give a warning to the vehicle driver, and the process of this routine ends.

In the drowsy driving prevention device of this embodiment configured as described above, two effective sensors capable of detecting pulse are first extracted in the effective sensor extraction routine shown in FIG. This is a process to ensure that the pulse signal can be detected consistently even if the position of the hand placed on the steering wheel changes, and by executing this process every time a peak is detected, the pulse signal can be detected well. You will be able to do this.

Next, in the peak detection process, when the detection signals @v1 and ■2 from the two pulse rate sensors are both greater than a predetermined value, the value obtained by adding these values is used as a pulse signal, and the peak is detected. However, as shown in FIG. 13, even if there is noise in the detection signals V1 and v2, the pulse signal
As for O, it becomes a good signal without that noise,
Even if there is some deviation between the two detection signal peaks, the averaged peak can be detected. Further, in this embodiment, when the pulse signal VO continues to rise for a predetermined period of time or more, and then falls for a predetermined period of time, the peak of the pulse signal is detected and the flag F1 is set. Even if both V1 and v2 exceed a predetermined value, the peak is not detected.

Here, in the above embodiment, two effective sensors are extracted from the 16 pulse sensors to obtain a pulse signal, but as an effective sensor, a pulse sensor that outputs a detection signal of a predetermined level or higher is selected. You may also extract all of them.

Further, in the embodiment described above, a large number of pulse sensors provided on the steering wheel are used, but the pulse sensors may be directly attached to the left and right hands of the vehicle driver, for example. Furthermore, when a large number of pulse sensors are provided on the steering wheel, the left and right constitute a pulse sensor group, and when two types of pulse signals output from each sensor group both exceed a predetermined value,
Drowsy driving may be detected by detecting the peak of the pulse signal and creating pulse data based on this.

[Effects of the Invention] As detailed above, in the drowsy driving detection device of the present invention, when the detection signals output from the plurality of pulse sensors both exceed a predetermined level, that signal is extracted as a valid pulse signal. and is configured to create pulse data based on the pulse signal. Therefore, even if the vehicle driver moves his hands and noise occurs in the detection signal, the noise can be effectively removed, and the obtained pulse rate data will be accurate pulse data that corresponds to the vehicle driver's heartbeat. Therefore, the detection accuracy of drowsy driving is improved, and even when issuing a warning to the vehicle driver, it becomes possible to execute the warning properly.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing the configuration of the present invention, FIG. 2 is a line diagram showing the translucency characteristics of blood, FIG. 3 is an explanatory diagram explaining the configuration and principle of a conventionally used pulse sensor, and FIG. Figure 4 is a diagram showing the detection signal obtained by the pulse sensor.
FIG. 5 is a block diagram showing the overall configuration of the drowsy driving prevention device of the embodiment, FIG. 6 is a layout diagram of the pulse sensor provided on the wheel ring of the steering wheel, and FIG. 7 is an explanation showing the configuration of the pulse sensor. 8 is an electric circuit diagram showing a pulse sensor and its drive circuit, FIG. 9 is a flow chart showing a pulse data calculation routine, FIG. 10 is a flow chart showing an effective sensor extraction routine, and FIG.
FIG. 1 is a flowchart showing a peak detection routine, FIG. 12 is a flowchart showing a dozing detection routine,
FIG. 13 is a diagram showing detection signals Vl and V2 output from two effective pulse sensors and a pulse signal obtained from these detection signals. M3, 11...Pulse sensor 17...LED 19a, 19b, 19c, 19d...Phototransistor 29...Control circuit 43...Microcomputer 53...Drive circuit

Claims (1)

[Claims] A plurality of pulse sensors that are composed of a pair of light emitting/receiving members and detect pulses from the hands of a vehicle driver, and a plurality of detection signals output from each of the pulse sensors are both at a predetermined level or higher. a pulse signal extraction means for extracting the detected signal as a valid pulse signal; and based on the pulse signal extracted by the pulse signal extraction means,
A pulse data creation means for creating pulse data of the vehicle driver; and a dozing detection means for comparing the created pulse data with preset reference pulse data and detecting dozing of the vehicle driver. A drowsy driving detection device characterized by: