JP2011164825A - Driving state determination apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a driving state determination apparatus which can suitably determine a driver's awakening state by detecting pressure distribution applied to a driver's seat during driving. <P>SOLUTION: The driving state determination apparatus includes a pressure detection means for detecting pressure distribution applied at least to a driver's seat back and a driver's seat part, and a determination means for determining a driver's awakening state on the basis of a change in the pressure distribution detected by the pressure detection means. Further, the determination means determines the driver's awakening state on the basis of whether a change in the detected pressure distribution has periodicity. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

The present invention relates to a driving state determination device capable of appropriately determining a driver's arousal state by detecting a pressure distribution acting on a driver's seat during driving.

The so-called dozing driving in which the driver who is driving the vehicle falls into a non-wake state is a major factor in traffic accidents. Therefore, there has been a demand for the development of a device that can efficiently prevent this dozing operation. In particular, in the development of such a dozing prevention device, it is possible to know what is a non-wake state that can cause a traffic accident called dozing, and to properly fall asleep based on this knowledge. The state needs to be detected.

For example, there is an apparatus that performs image recognition on an image of a driver's head photographed by a camera to determine the driver's arousal state (Patent Document 1). Specifically, it is a method of detecting a look away or a doze from the image data of the driver's head taken using an indoor camera already installed to prevent intrusion of suspicious persons.

As another example, there is a device that detects a dozing state by a decrease in pressure acting on a driver's seat (Patent Document 2). Specifically, this is a method of detecting whether or not the driver is asleep by detecting the driver's driving posture based on the gripping force of the driver acting on the steering wheel and the pressure acting on the driver's seat. There is also an apparatus that avoids a side-by-side operation by detecting the driver's driving posture from the pressure acting on the seat, although it is not intended to detect and judge a dozing state (Patent Document 3).

However, in the case of the device of Patent Document 1, the state of wakefulness is determined from the driver's gaze direction and the behavior of the face tilt, and the head behavior in a normal state and the head behavior in an abnormal state such as dozing Since it is difficult to distinguish between the two, there is a possibility of false detection. In addition, in the case of the apparatus of Patent Document 1, it cannot be applied to a vehicle in which an indoor camera is not installed in the first place or a vehicle in which an increase in cost due to the installation of a new indoor camera is not desired.

Also, in the case of the device of Patent Document 2, the dozing state is determined only by the pressure acting on the driver's seat being lowered, and the possibility of erroneous detection is high. On the other hand, in the case of the device of Patent Document 3, a control logic is constructed as to what is an aside operation, and the pressure condition acting on the driver's seat is used as a part of this logic, The detection of a representative non-wake state requires a different logic construction, and the device of Patent Document 3 cannot be substituted.

JP 2005-62911 A JP-A-4-78622 JP 2000-172965 A

The present invention has been made in view of the above problems, and it is possible to determine the driver's arousal state by focusing on the change in pressure distribution acting on the driver's seat and detecting this change in pressure distribution. An object of the present invention is to provide an operating state determination device.

The driving state determination device according to the present invention includes a pressure detection unit that detects a pressure distribution acting on at least a driver's seat back and a headrest, and a driver's arousal state based on a change in the pressure distribution detected by the pressure detection unit. And determining means for determining.

It is known that when the driver falls into a so-called dozing state, a specific behavior is made (generally referred to as “cooking”). It has been found that the driver's behavior in such a state has periodicity. In the driving state determination device of the present invention, it is assumed that the state in which the behavior of the driver with periodicity appears is a dangerous “non-wake state” typified by falling asleep. Specifically, this driving state determination device detects a “change in pressure distribution” acting on the driver's seat, and determines whether or not this change has “periodicity”. Can be determined.

In addition, the operating state determination device of the present invention knows that it is sufficient to detect the change in the pressure distribution of the “seat back and seat seat portion” out of the pressure distribution acting on the driver's seat, and This is advantageous in that it is possible to provide a simple and clear control configuration in detecting whether or not the driver is in the “non-wake state” in that the “wake state” of the driver is determined based on the above.

Moreover, it is preferable that the said determination means in the driving | running state determination apparatus of this invention determines a driver | operator's arousal state based on whether the change of the detected pressure distribution has periodicity.

In this driving state determination device, it is determined whether or not the change in pressure distribution has “periodicity” after determining whether or not the driver is in the “non-wake state”. It is further advantageous in that it is possible to provide a clear control structure in detecting whether or not the driver is in the “non-wake state” by using the periodicity of the pressure distribution change as a control logic in the driving state determination device. .

According to the driving state determination device of the present invention, attention is paid to a change in the pressure distribution acting on the driver's seat, and the driving in which the driver's arousal state can be determined by detecting the change in the pressure distribution. A state determination device is provided, and a driver's arousal state (sleeping state) can be determined by a simple and clear control device.

It is a block diagram which shows an example of the driving | running state judgment apparatus of this invention, and its peripheral device. It is the block diagram which showed an example of the detail of the driving | running state judgment apparatus of FIG. It is the schematic which copied the state where the driver sat on the seat. It is a block diagram which shows the detail of the determination means shown in the block diagram of FIG. It is a flowchart which shows the dozing determination process (A pattern) performed by the arousal state determination means of FIG. FIG. 6 is a continuation of the flowchart showing the dozing determination process of FIG. 5. It is an example which shows the change of the pressure distribution from each pressure sensor. It is the schematic diagram which showed the pressure distribution of the hip part vicinity which acts on a seat seat part, (a) is normal time, (b) has shown the time of dozing. It is a flowchart which shows the dozing determination process (B pattern) performed by the arousal state determination means of FIG. FIG. 10 is a continuation of the flowchart showing the dozing determination process of FIG. 9. It is an example which shows the change of the pressure distribution from each pressure sensor.

Embodiments of the present invention will be described below with reference to the drawings.
First, FIG. 1 is a block diagram showing an example of the driving state determination device 10 and its peripheral devices according to the present invention, and FIG. 2 is a block diagram showing an example of details of the driving state determination device 10 of FIG. FIG. 3 is a schematic view showing a state in which the driver is sitting on the seat.

As shown in FIG. 1, the driving state determination device 10 first receives individual pressure signals from a pressure sensor 16 installed on a driver's seat 15. As shown in FIG. 3, the driver 11 is carried on the seat 15 while the vehicle is traveling. Specifically, the seat 15 carries each part of the driver 11, the head portion 11c is carried by the headrest 15c, the back portion 11a is carried by the seat back 15a, and the collar portion 11b is carried by the seat seat portion 15b. Further, a head pressure sensor 16c, a back pressure sensor 16a, and a seat pressure sensor 16b are disposed (built in) in the headrest 15c, the seat back 15a, and the seat seat 15b, respectively, and detect the acting pressure. To do. However, the pressure sensor 15 is not necessarily required for the head portion, the back portion, and the seat portion, and is determined according to the dozing determination logic described later.

Returning to FIG. 1 again, pressure signals from the back pressure sensor 16 a, the seat pressure sensor 16 b, and the head pressure sensor 16 c are transmitted to the driving state determination device 10. As shown in FIG. 2, the operating state determination device 10 includes a pressure distribution detection unit 12 and a determination unit 14. The pressure distribution detecting means 12 detects and sets a pressure peak from the pressure signal received from the pressure sensor 16.

Specifically, in the case of the back pressure sensor 16a disposed on the seat back 15a, one on each of the left and right sides of the seat back 15a, preferably one each on the top and bottom (that is, four on the back). The pressure peak value at each location and its position are detected. Further, in the case of the seat pressure sensor 16b disposed in the seat seat portion 15b, like the back pressure sensor 16a, one each on the left and right sides of the seat seat portion 15b, preferably one each in the front and rear are disposed (that is, 4 points are arranged on the seat), and the pressure peak value and the position of each point are detected. Further, in the case of the head pressure sensor 16c disposed on the headrest 15c, the headrest sensor 15c is disposed at one location to detect the pressure peak value and the position thereof. The pressure sensor 16 may be a general-purpose sheet. Further, the detected pressure peak has a certain range in order to prevent noise, and may have a width as large as so-called surface pressure.

The pressure data from the pressure distribution detection means 12 is determined by the determination means 14. As shown in the block diagram of FIG. 4, the determination unit 14 includes a normal posture determination unit 141, an arousal state determination unit 142, a vehicle speed determination unit 143, and a massage mode selection unit 144. First, the normal posture determination means 141 determines and stores a normal driving posture (normal driving posture) in which a person is not asleep. The determination of the normal driving posture is made from two viewpoints. First of all, the normal driving posture specific to each individual is set. One is set as a normal driving posture from the pressure value and position of each pressure peak detected by the pressure distribution detecting means 12. Specifically, the distance between the pressure peak positions detected by the pressure sensors 16a to 16c and the pressure values thereof, and the pressure peak positions of the back pressure sensor 16 and the seat sensor 16b disposed on the left and right sides, The normal driving posture of each individual is set by the distance between the pressure peak positions of the back pressure sensor 16 and the seat sensor 16b arranged in the above. The other is to determine a posture with the largest number of times as a normal driving posture by setting a pressure value and a position where a pressure peak appears long.

Next, the awakening state determination means 142 determines the awakening state of the driver 11, that is, determines whether or not the driver 11 is in a dozing state. The awakening state determination means 142 determines from the temporal change in the pressure distribution acting on the seat 15, but in this determination, a precondition for determination is set. For example,
(1) It has been operating continuously for a predetermined time from the start of operation.
(2) Although the condition of (1) is not satisfied, the vehicle is operated for a predetermined time or more before the current operation.
(3) A doze is determined before driving this time.
In such a case, the detection level of dozing determination may be set high because it is particularly easy to fall into a dozing state.

In some cases, the detection level setting for the dozing determination is made to depend on the vehicle speed using the vehicle speed determining means 143. In this case, the vehicle speed determination means 143 receives the vehicle speed signal 18 (see FIG. 1) from the speed sensor 18 and classifies the vehicle speed into a plurality of levels. Set the detection level. The greater the vehicle speed, the greater the risk, so it is easier to be determined to fall asleep.

Next, returning to the wakefulness determination means 142, the specific determination concept of the wakefulness state (sleeping state) will be described. First, the concept about the relationship between the pressure distribution detected by the seat back 15a, the seat seat 15b, and the headrest 15c and the arousal state will be described.

First, an arousal state may be determined only from a change in the pressure distribution of the seat back 15a. This is based on the fact that in the dozing state, there is a high possibility that the back portion 11a of the driver 11 is separated from the seat back 15a. More preferably, paying attention to the pressure distribution from the back pressure sensor 16a disposed on the upper left and right sides of the seat back 15a among the changes in the pressure distribution on the seat back 15a, the pressure distribution on the upper portion of the seat back 15a Whether the driver 11 is awake is determined based on whether or not the vehicle has changed. According to this determination, it is possible to capture a phenomenon in which the upper part of the back part 11a of the driver 11 swings to the left and right when taking a nap, and the awakening state of the driver 11 can be determined more accurately.

Moreover, the case where an arousal state is judged only from the change of the pressure distribution of the seat seat part 15b is also considered. This is based on the fact that the center of gravity of the buttocks 11b of the driver 11 is likely to move at the seat seat 15b in the dozing state. More preferably, paying attention to the pressure distribution from the seat pressure sensor 16b disposed at the front and rear portions of the seat seat portion 15b as described above, whether or not the pressure distribution of the seat seat portion 15b has changed in the front-rear direction. Based on this, the awakening state of the driver 11 is determined. According to this determination, the phenomenon that the center of gravity of the buttocks 11b of the driver 11 sways in the front-rear direction when snoozing can be captured, and the awakening state of the driver 11 can be determined more accurately.

FIG. 8 is a pressure distribution schematic diagram showing how the pressure distribution of the flange portion 11b in the seat seat portion 15b moves forward of the vehicle. The hatched portion shows the pressure peak.

Further, in order to more accurately determine the dozing state by the awake state determination unit 142, the pressure distribution changes in the seat back 15a and the seat seat 15b have periodicity, that is, the pressure distribution changes within a predetermined time. The condition of being repeated several times is required. This is to prevent the driver 11 from happening to be close to a dozing state, and if the same pressure distribution change is repeated, it is possible to reliably distinguish the dozing state or not.

Further, detection of a change in the pressure distribution of the headrest 15c is not essential but may be required. This is because the head 11c normally operates first when it becomes a doze state. In this case, the change in the pressure distribution of the headrest 15c is usually determined by whether or not the pressure value becomes zero.

Here, an example of logic for determining whether or not the wakefulness determination unit 142 falls into a doze state will be described in detail as an A pattern and a B pattern. First, the control flow of the wakefulness determination means 142 in the A pattern will be described with reference to FIGS. 5 to 6, and the time-series display of the change in pressure distribution acting on the seat will be described with reference to FIG. 7. In the A pattern, a state in which the head 11c of the driver 11 tilts forward and then returns to the original state is repeated (repeated) several times, and is determined to be a doze state. First, it is determined whether or not the pressure acting on the headrest 15c is detected (S10). Thereby, it is determined that the head 11c of the driver 11 is inclined forward. 7 shows that the pressure peak value of the headrest 15c reaches zero.

If no pressure is detected, it is determined whether or not the pressure value of the pressure peak at the top of the seat back 15a (hereinafter referred to as “pressure peak value”) is decreasing (S12). Thereby, it is determined that the back portion 11a of the driver 11 is directed forward from the seat back 15a. Referring to the second row from the top in FIG. 7, it can be seen that the pressure peak value at the upper part of the seat back 15a (the upper side of the back part 11a) decreases with a delay from the pressure peak value of the headrest 15c.

If it is determined that the pressure peak value at the upper part of the seat back 15a has decreased, it is determined whether or not the position of the pressure peak of the seat seat 15b has moved forward (S14). Thereby, it is determined that the entire body of the driver 11 is inclined forward. The forward movement of the pressure peak position can also be determined from a decrease in the pressure peak value at the rear of the seat seat 15b or an increase in the pressure peak value at the front of the seat seat 15b. Referring to the third to fourth stages from the top in FIG. 7, the pressure peak value at the rear portion (behind the flange portion 11b) of the seat seat portion 15b decreases with a delay from the pressure peak value of the seat back 15a. It can be seen that the pressure peak value at the front part of 15b (in front of the flange part 11b) is increasing at the rear part of the seat seat part 15b (behind the flange part 11b).

Further, it is determined that the series of phenomena has occurred within a predetermined time (approximately within a few seconds). That is, it is determined whether or not the time t1 required for the determination steps S10 to S14 is within a predetermined time T1 (t1 ≦ T1) (S16). FIG. 7 shows an example where t1 ≦ T1.
Further, it is also determined whether or not the change rate of the pressure peak value detected by the headrest 15c, the seat back 15a, and the seat portion 15b, that is, the change rate of the pressure distribution is moderate (S18). This is because in the dozing state, the movement is slower than the normal driving posture.

Next, the time until the changed pressure distribution is restored is set. Specifically, as shown in FIG. 7, a time t2 from when the pressure peak value changes until it returns to the original pressure peak value is measured (S20). Depending on the time t2, a different doze determination is made. First, it is determined whether the time t2 until the pressure peak value returns is longer than the predetermined time T2 (whether t2 ≧ T2) (S22). That t2 is large means that the state in which the pressure distribution has changed has been continued for a long time, and is a state in which the user has fallen asleep. When this state is reached, it is determined that the patient is dozing (S32).

Also, if it is determined that the time t2 until the pressure peak value returns is shorter than the predetermined time T2 (t2 ≦ T2) (S22), it cannot be said that the user has fallen asleep, but if it repeats many times, it is a doze state It is thought that. Therefore, in line with this idea, first, the number of times C1 (the number of iterations C1) in which the entire determination process of S10 to S22 is repeated is added and set (S24). Thereafter, it is determined whether or not the entire determination process of S10 to S22 has been repeated N times or more, that is, whether or not the number of repetitions C1 ≧ N. When it is determined that the entire determination process of S10 to S22 has been repeated N times or more, the time t3 required for the number of repetitions (number of repetitions) C1 is determined to be within a predetermined time T3 (t3 ≦ T3) (S28) It is determined that the state is a so-called “cook licking” state that repeats awakening and non-awakening, and is a dozing state (S32). If it is determined that the time t3 required for the number of repetitions (number of repetitions) C1 of the entire determination process of S10 to S22 is equal to or greater than the predetermined time T3 (t3 ≧ T3) (S28), the number of repetitions C1 is subtracted by one. Processing is performed (S30).

Secondly, the control flow of the arousal state determination means 142 in the B pattern will be described with reference to FIGS. 9 to 10, and the time series display of the change in pressure distribution acting on the seat will be described with reference to FIG. 11. In the B pattern, a state in which the head 11c of the driver 11 tilts to the left side and then returns to the original state is repeated (repeated) several times, and is determined to be a doze state. First, it is determined whether or not the pressure acting on the headrest 15c is detected (S40). 11 shows that the pressure peak value of the headrest 15c has reached zero.

If no pressure is detected, it is determined whether or not the pressure peak value on the upper right side of the seat back 15a has decreased (S42). Thereby, it is determined that the back portion 11a of the driver 11 is directed leftward from the seat back 15a. Referring to the second row from the top in FIG. 11, it can be seen that the pressure peak value on the upper right side of the back of the seat back 15a decreases with a delay from the pressure peak value of the headrest 15c.

If it is determined that the pressure peak value on the right upper side of the seat back 15a has decreased, it is subsequently determined whether or not the pressure peak value on the left upper side of the seat back 15a has decreased (S44). Referring to the third row from the top in FIG. 11, it can be seen that the pressure peak value on the left side on the back of the seat back 15a decreases after the pressure peak value on the right side on the back of the seat back 15a. Further, as shown in the second to third stages of FIG. 11, the pressure peak value is larger after the pressure peak value on the left side on the back portion is decreased than after the pressure peak value on the right side on the back portion of the seat back 15a is decreased. Recognize. This is because when the driver 11 is tilted forward on the left side, the right side of the back part is directed away from the seat back 15a.

Next, it is determined whether or not the forward movement of the pressure peak point on the left side of the seat seat portion 15b and the peak value have increased (S45). As a result, it is determined that the entire body of the driver 11 is tilted to the left. Referring to the fourth row from the top in FIG. 11, it can be seen that the pressure peak value on the left side of the seat seat portion 15b (the left side of the flange portion 11b) increases substantially simultaneously with the pressure peak value of the seat back 15a.

Further, when it is determined that the pressure peak value of the seat seat 15b is increased, it is determined that the above-described series of phenomena has occurred within a predetermined time (approximately within a few seconds) (S46). That is, it is determined whether the time t4 required for the determination process of S40 to S45 is within the predetermined time T4 (t4 ≦ T4) (S48). FIG. 11 shows an example where t4 ≦ T4. It is also determined whether or not the change rate of the pressure peak value detected by the headrest 15c, the seat back 15a, and the seat portion 15b, that is, the change rate of the pressure distribution is moderate (S48). This is because in the dozing state, the movement is slower than the normal driving posture.

Next, the time until the changed pressure distribution is restored is set. Specifically, as shown in FIG. 11, a time t5 from when the pressure peak value changes until it returns to the original pressure peak value is measured (S50). Depending on the length of this time t5, a different doze determination is made. First, it is determined whether the time t5 until the pressure peak value returns is longer than the predetermined time T5 (whether t5 ≧ T5) (S52). That t5 is large means that the state in which the pressure distribution has changed has been continued for a long time, and is a state in which the user has fallen asleep. When this state is reached, it is determined that the patient is dozing (S62).

If it is determined that the time t5 until the pressure peak value returns is shorter than the predetermined time T5 (t5 ≦ T5) (S52), it cannot be said that the user has fallen asleep, but if it repeats many times, it is a doze state It is thought that. Therefore, in line with this idea, first, the number of times C2 (the number of iterations C2) in which the entire determination process of S40 to S52 is repeated is added and set (S54). Thereafter, it is determined whether or not the entire determination process of S40 to S52 has been repeated N times or more, that is, whether or not the number of repetitions C2 ≧ N (S56). When it is determined that the entire determination process of S40 to S52 has been repeated N times or more, the time t6 required for the number of repetitions (number of repetitions) C2 is determined to be within the predetermined time T6 (t6 ≦ T6) (S58) It is determined that the state is a so-called “cook licking” state that repeats awakening and non-awakening, and is a dozing state (S62). If it is determined that the time t6 required for the number of times (the number of repetitions) C2 of repeating the entire determination process of S40 to S52 is equal to or greater than the predetermined time T6 (t6 ≧ T6) (S58), the number of repetitions C2 is subtracted by one. Processing is performed (S60).

In the B pattern described above, a state in which the head 11c of the driver 11 tilts to the left and then returns to the original state is repeated (repeated) several times. A case where the head 11c of the head is inclined to the right side or a case where the head portion 11c swings to the right and left can be similarly considered.

Returning to FIG. 1 to FIG. 2 and FIG. As shown in FIG. 4, the determination unit 14 of the driving state determination apparatus 10 includes a massage mode selection unit 144 in addition to the normal posture determination unit 141, the awake state determination unit 142, and the vehicle speed determination unit 143 described above. When it is determined that the driving state determination device 10 is in the dozing state, the driver 11 is warned by performing massage according to the detection level (described above). The warning by the massage is advantageous in that the driver 11 does not feel uncomfortable compared to the warning sound or the like even if the detection level is set to be lower than necessary and it is determined to be asleep. The massage mode selection means 144 of the determination means 14 selects massage according to the detection level. Referring to FIG. 1, the present driving state determination device 10 receives a signal from the mode selection switch 20, but the massage mode selection means 144 also performs a process of selecting a massage mode based on the signal from the mode selection switch 20. ing.

Further, a determination signal is transmitted from the driving state determination device 10 to the control drive unit 22. Thereafter, the control signal is converted into a drive signal by the control drive unit 22 and drive control of the actuator 24 is performed. The actuator 24 includes a back actuator 24a and a seat actuator 24b, and is built in the seat back 15a and the seat seat 15b, respectively.

As described above, according to the driving state determination device of the present invention, the driver's arousal state can be determined with a simple and clear control configuration by detecting the change in the pressure distribution acting on the driver's seat.
As mentioned above, although embodiment of this invention has been described, the driving | running state detection apparatus of this invention is not limited to this, The other modified example which does not deviate from the spirit and teaching of description of a claim It will be apparent to those skilled in the art that there are variations and improvements.

DESCRIPTION OF SYMBOLS 10 Driving | running state determination apparatus 12 Pressure distribution detection means 14 Determination means 15 Seat 15a Seat back 15b Seat seat part 15c Headrest 16 Pressure sensor 16a Back part pressure sensor 16b Seat part pressure sensor 16c Head pressure sensor 18 Vehicle speed signal (speed sensor)
20 Mode selection switch 22 Control drive unit 24 Actuator 141 Normal driving posture determination unit 142 Awake state determination unit (slumber determination unit)
143 Vehicle speed judgment means 144 Massage mode selection means

Claims (2)

Pressure detection means for detecting a pressure distribution acting on at least the driver's seat back and seat seat;
A driving state determination device comprising: a determination unit that determines a driver's arousal state based on a change in pressure distribution detected by the pressure detection unit. The driving state determination device according to claim 1, wherein the determination unit determines a driver's arousal state based on whether or not the detected change in pressure distribution has periodicity.

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