JP5293356B2 - Arousal level drop determination device - Google Patents

Description

  The present invention relates to a wakefulness level decrease determination device, and more particularly, to a wakefulness level decrease determination device that determines a decrease in wakefulness level in a driver who drives a vehicle.

  When a driver who drives a vehicle suffers from a decrease in arousal level due to drowsiness or the like, the driving of the vehicle may be hindered. Therefore, as a wakefulness level decrease determination device that determines a decrease in wakefulness level when the driver's wakefulness level decreases, conventionally, the vehicle's steering angle is detected, and a dozing operation is detected based on the detected steering angle. An operation detection device is known (see, for example, Patent Document 1).

  In this drowsy driving detection device, a delay signal is generated by performing a delay process on the steering angle signal obtained by detecting the steering angle, and a difference output is obtained from the difference between the steering angle signal and the delay signal. The zero point is detected from the change in the sign in the difference output, the corrected steering cycle is obtained from the detected zero point, and the driver's sleepiness is detected based on the corrected steering cycle.

Japanese Patent No. 2970384

  However, the dozing operation detection device disclosed in Patent Document 1 only obtains a differential output from the steering angle signal and the delay signal and obtains a corrected steering cycle. For this reason, since the shape of the traveling path of the vehicle is not taken into consideration, there is a problem that the accuracy of detecting drowsiness (decrease in wakefulness) may be lowered depending on the form of the traveling path.

  Accordingly, an object of the present invention is to provide a wakefulness level decrease determination device that can accurately determine a decrease in the wakefulness level of a driver in accordance with the traveling path of a vehicle.

A wakefulness reduction determination device according to the present invention that solves the above-described problem is a wakefulness reduction determination device that determines a state of reduced wakefulness of a driver who drives a vehicle based on a steering state of the vehicle, the steering angle of the vehicle A steering angle detection means for detecting a steering change index detection means for detecting a steering change index for a driver driving the vehicle based on the steering angle detected by the steering angle detection means, and a curve state on the travel path of the vehicle. Detected by the curve state detection means, the wakefulness level reduction determination means for determining that the driver's wakefulness level is in a lowered state when the steering change index exceeds a predetermined threshold, and the curve state detection means based on the curve state, and a awareness decrease determination threshold setting means for setting the awareness decrease determination threshold value used in the awareness decrease determination means, the steering change indicator is modified Wherein the steering change power der Rukoto is an integral value of the difference signal between the steering angle signal and the steering angle delay signal during one cycle of the steering cycle.

  The threshold for wakefulness determination according to the present invention is based on the curve state of the travel path on which the vehicle travels detected by the curve state detection means when determining the driver's wakefulness. The threshold value is set. When the curve state of the travel path of the vehicle changes, the magnitude of the curve state affects the steering change index. For this reason, by setting the arousal level decrease determination threshold value used when the driver's arousal level decreases when the steering change index exceeds the arousal level decrease determination threshold value, The decrease in the driver's arousal level can be accurately determined according to the travel path.

  The “curve state” in the present invention can be expressed by, for example, a curve radius (curve R), a curvature of the curve, or the like.

  Here, the arousal level decrease determination threshold value setting means may be configured to increase the awakening level decrease determination threshold value as the curve state is steeper.

  As the curve state is steeper, the influence on the steering change index becomes larger. For this reason, as the curve is steeper, by increasing the arousal level decrease determination threshold value, it is possible to accurately determine the decrease in the driver's arousal level according to the traveling path of the vehicle.

Furthermore, the steering change index detection means has a steering cycle calculation means for calculating a corrected steering cycle that becomes a steering change index based on the steering angle detected by the steering angle detection means. Delay means for delaying a steering angle signal based on the steering angle detected by the detection means for a predetermined time; and difference calculating means for calculating a difference between the steering angle signal and a delay signal obtained by delaying the steering angle signal by the delay means; A zero point detecting means for detecting a zero point from a change in the sign of the difference output based on a calculation result in the difference calculating means, and calculating an interval between the zero points detected by the zero point detecting means as a corrected steering cycle. It can be set as an aspect.

  As described above, by using the difference between the steering angle signal and the steering angle delay signal obtained by delaying the steering angle signal as the steering change index, the driver's steering change can be suitably determined.

The steering change index detecting means has a steering period calculating means for calculating a corrected steering period based on the steering angle detected by the steering angle detecting means, and the steering period calculating means delays the steering angle signal for a predetermined time. Delay means for calculating, a difference means for calculating a difference between the detected steering angle signal and the delay signal from the delay means, and a zero point detection means for detecting a zero point from a change in the sign of the difference output from the difference means, The interval between the zero points detected by the zero point detection means is calculated as a corrected steering cycle, and is composed of an integrated value of the difference output during one cycle of the corrected steering cycle, and the steering change power as a steering change index is calculated. And a steering change power calculating means for calculating.

  Thus, the steering change of the driver can be more suitably determined by using the steering change power that is an integral value of the difference output during one period of the correction steering cycle as the steering change index. As the steering change index, in addition to the steering change power in the present invention, a time corresponding to one cycle of the corrected steering cycle when obtaining the steering change power, the maximum value of the steering angle amplitude in the corrected steering cycle, or the like can also be used. .

  Further, the vehicle speed detection means for detecting the vehicle speed of the vehicle is further provided, and the curve state detection means is based on the change in the steering angle detected by the steering angle detection means and the vehicle speed detected by the vehicle speed detection means. It can be set as the aspect which detects the curve state in a road.

  Thus, by obtaining the curve state based on the steering angle and the vehicle speed of the vehicle, it is possible to eliminate the need for a separate detection means for detecting the curve state. Therefore, the apparatus configuration can be simplified correspondingly.

A wakefulness level decrease determination device according to the present invention that solves the above-described problem is a wakefulness level decrease determination device that determines a reduced state of wakefulness level of a driver driving a vehicle based on a steering state of the vehicle. Steering angle detecting means for detecting a steering angle, steering change index detecting means for detecting a steering change index in a driver who drives the vehicle based on the steering angle detected by the steering angle detecting means, and a curve on the traveling path of the vehicle Comparison of a curve state detection means for detecting a state, a threshold value set according to the curve state detected by the curve state detection means, and a steering change index detected by the threshold value and the steering change index detection means based on, and a awareness decrease determining means for determining awareness of the driver, steering change indicator, the difference between the steering angle signal and the steering angle delay signal during one cycle of the corrective steering cycle Wherein the steering change power der Rukoto is an integral value in the signal.

  According to the arousal level lowering determination apparatus according to the present invention, it is possible to accurately determine the decrease in the driver's arousal level according to the traveling path of the vehicle.

It is a block block diagram of the arousal level fall determination apparatus which concerns on 1st Embodiment. It is a flowchart which shows the process sequence of the arousal level fall determination apparatus. It is a flowchart which shows the procedure of a steering change power calculation process. (A) is a graph showing the change over time of the steering angle signal and the delay signal, (b) is a graph showing the change over time of the difference signal, and (c) is a graph showing the change over time of the absolute value of the difference signal. is there. It is a flowchart which shows the procedure of a threshold value determination process. (A) is a graph which shows a time-dependent change of the steering angle signal of a long period, (b) is explanatory drawing for calculating | requiring a steering angle vector. It is a graph which shows a time-dependent change of the total steering change power which multiplied the steering change power by the correction steering cycle. It is a block block diagram of the wakefulness fall determination apparatus which concerns on 2nd Embodiment. 5 is a graph showing changes with time of an actual curve R and a reference curve R. (A) is a graph for explaining an actual curve R unit time vector and a reference curve R unit time vector, and (b) is a graph in which the starting point of the actual curve R unit time vector and the reference curve R unit time vector is zero. (C) is a graph showing an actual curve R vector deviation curve and a reference curve R vector deviation curve. It is a graph which shows a steering change power statistical curve and a reference | standard steering change power statistical curve.

  Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. In the description of the drawings, the same elements are denoted by the same reference numerals, and redundant description is omitted. For the convenience of illustration, the dimensional ratios in the drawings do not necessarily match those described.

  FIG. 1 is a block configuration diagram of a wakefulness decrease determination apparatus according to the first embodiment of the present invention. As shown in FIG. 1, the wakefulness level decrease determination device according to the present embodiment includes a wakefulness level decrease determination ECU 1. A steering angle sensor 2 and a vehicle speed sensor 3 are connected to the awakening level decrease determination ECU 1. Further, an alarm device 4 is connected to the arousal level decrease determination ECU 1. The arousal level decrease determination ECU 1 includes a steering change power calculation unit 11, a curve R calculation unit 12, a wakefulness level decrease determination threshold value determination unit 13, and a wakefulness level decrease determination unit 14. Further, the steering change power calculation unit 11 is provided with a delay circuit 11A, a difference circuit 11B, a zero point detection circuit 11C, and a steering change power calculation circuit 11D.

  The steering angle sensor 2 is a sensor that detects the steering angle of the steering wheel input by the driver. The steering angle sensor 2 transmits the detected steering angle as a steering angle signal to the delay circuit 11A and the difference circuit 11B provided in the steering change power calculation unit 11 in the arousal level reduction determination ECU 1.

  The vehicle speed sensor 3 is a sensor that detects the speed of the vehicle. The vehicle speed sensor 3 transmits the detected vehicle speed as a vehicle speed signal to the curve R calculation unit 12 in the arousal level decrease determination ECU 1.

  The alarm device 4 is provided in a vehicle, for example, and includes a speaker that emits voice to the driver. The alarm device 4 outputs a sound corresponding to the arousal level decrease information output from the arousal level decrease determination ECU 1 to urge the driver to pay attention.

  The steering change power calculation unit 11 in the wakefulness reduction determination ECU 1 calculates a corrected steering cycle based on the steering angle signal transmitted from the steering angle sensor 2. In calculating the corrected steering cycle, the delay circuit 11A performs a delay process on the steering angle signal transmitted from the steering angle sensor 2 to generate a delay signal. The delay circuit 11A outputs the generated delay signal to the difference circuit 11B.

  The difference circuit 11B performs a difference process on the steering angle signal transmitted from the steering angle sensor 2 and the delay signal output from the delay circuit to generate a difference signal. The difference circuit 11B outputs the generated difference signal to the zero point detection circuit 11C and the steering change power calculation circuit 11D.

  The zero point detection circuit 11C detects the zero point of the steering angle change based on the difference signal output from the difference circuit 11B. The zero point detection circuit 11C outputs a zero point signal based on the detected zero point to the steering change power calculation circuit 11D.

  The steering change power calculation circuit 11D calculates a steering change power serving as a steering change index based on the difference signal output from the difference circuit 11B and the zero point signal output from the zero point detection circuit 11C. This steering change power is composed of an integral value of the difference signal during one period of the corrected steering cycle. The steering change power calculation circuit 11 </ b> D outputs a steering change power signal based on the calculated steering change power to the arousal level decrease determination unit 14.

  The curve R calculation unit 12 calculates the curve R of the travel path of the vehicle based on the steering angle signal transmitted from the steering angle sensor 2 and the vehicle speed signal transmitted from the vehicle speed sensor 3. When calculating the curve R of the travel path of the vehicle, the long-time interval steering angle in the steering angle signal transmitted from the steering angle sensor 2 is used. The curve R calculation unit 12 outputs a curve R signal based on the calculated curve R to the arousal level decrease determination threshold value determination unit 13.

  Based on the curve R signal output from the curve R calculation unit 12, the wakefulness level decrease determination threshold value determination unit 13 determines a wakefulness level decrease determination threshold value when performing the wakefulness level decrease determination. The arousal level decrease determination threshold value determination unit 13 stores a wakefulness level decrease determination threshold value map indicating a correspondence relationship between the curve R and the arousal level decrease determination threshold value. In the wakefulness level decrease determination threshold value map, the wakefulness level decrease determination threshold value is set such that the smaller the curve R (the steeper curve), the larger the wakefulness level decrease determination threshold value. The arousal level decrease determination threshold value determination unit 13 outputs a wakefulness level decrease determination threshold value signal based on the determined arousal level decrease determination threshold value to the arousal level decrease determination unit 14.

  The arousal level reduction determination unit 14 outputs the steering change power based on the steering change power signal output from the steering change power calculation circuit 11D in the steering change power calculation unit 11 and the arousal level reduction determination threshold value determination unit 13. Compare with the arousal level drop threshold. When the steering change power exceeds the arousal level decrease determination threshold value as a result of the comparison between the steering change power and the arousal level decrease determination threshold value, the arousal level decrease determination unit 14 sends an alarm signal to the alarm device 4. Send to.

  Next, the operation of the wakefulness reduction determination apparatus according to this embodiment will be described. FIG. 2 is a flowchart showing a processing procedure of the arousal level lowering determination apparatus. As shown in FIG. 2, in the wakefulness reduction determination device, the wakefulness reduction determination ECU 1 first acquires the steering angle of the vehicle based on the steering angle signal transmitted from the steering angle sensor 2 (S 1), and then The vehicle speed of the vehicle based on the vehicle speed signal transmitted from the vehicle speed sensor 3 is acquired (S2).

  Subsequently, the steering change power calculation unit 11 performs a steering power change calculation process for calculating the steering change power based on the acquired steering angle of the vehicle (S3). The steering change power calculation process is performed according to the flow shown in FIG. As shown in FIG. 3, in the steering change power calculation process, first, the delay circuit 11A performs a delay process on the steering angle signal transmitted from the steering angle sensor 2 (S11) to generate a steering angle delay signal. To do. In this embodiment, the delay time for performing the delay process is set to 0.2S.

  Subsequently, a steering angle difference calculation process is performed in the difference circuit 11B (S12). In the steering angle difference calculation process, the steering angle delay signal generated by the delay process is subtracted from the steering angle signal transmitted from the steering angle sensor 2 in accordance with the change with time to generate a steering angle difference signal. FIG. 4A shows changes with time of the steering angle signal and the steering angle delay signal. As shown in FIG. 4A, the steering angle signal SS and the steering angle delay signal DS have the same waveform, and the steering angle delay signal is in a position state where the steering angle signal is shifted. . By performing difference processing on the steering angle signal SS and the steering angle delay signal DS, a steering angle difference signal HS having a waveform shown in FIG. 4B is generated.

  When the steering angle difference calculation process is completed, the absolute value process is performed in the zero point detection circuit 11C (S13). In the absolute value process, a process of converting a negative sign to a positive sign is performed in a range where the steering angle difference amplitude in the steering angle difference signal HS is in a minus region. By performing absolute value processing on the steering angle difference signal HS having the waveform shown in FIG. 4B, the steering angle absolute value signal AS shown in FIG. 4C is generated.

  After generating the steering angle absolute value signal AS, the zero point detection circuit 11C detects the zero point in the steering angle difference signal HS (S14). The zero point detection circuit 11C detects the turning point in the steering angle absolute value signal AS as the zero point in the steering angle difference signal HS.

  When the zero point is detected in this way, the steering change power calculation circuit 11D detects the steering cycle (S15). As the steering cycle, the interval between the zero points taken out by the zero point detection circuit 11C is detected as the steering cycle. After detecting the steering cycle, the steering change power calculation circuit 11D calculates the steering change power for each detected steering cycle (S16). The steering cycle power is calculated by time-integrating the steering angle absolute value signal AS. Thus, the steering change power calculation process is terminated.

  When the steering change power calculation process is completed, the arousal level decrease determination threshold value determination process is performed (S4). The arousal level decrease determination threshold value determination process is performed according to the procedure shown in FIG. As shown in FIG. 5, in the arousal level decrease determination threshold value determination process, first, the curve R calculation unit 12 calculates the long-time interval steering angle amplitude based on the steering angle signal transmitted from the steering angle sensor 2. Store (21). Based on the long-time interval steering angle amplitude stored here, a long-term interval steering angle change with time is obtained.

  For example, when the vehicle is traveling on a curved road, the long-time interval steering angle change with time draws a waveform as shown in FIG. In the waveform shown in FIG. 6A, for example, the time from when the steering angle amplitude becomes 0 or more until it becomes 0 again is about 10 seconds. Therefore, compared with the change with time of the steering angle signal shown in FIG. 4A, the cycle is very long. In other words, the change with time of the steering angle signal shown in FIG. 4A is a minute change obtained by extracting a part of the waveform shown in FIG.

  Subsequently, the curve R calculation unit 12 stores the long-time interval vehicle speed based on the vehicle speed signal transmitted from the vehicle speed sensor 3 (S22). Based on the long-time interval vehicle speed stored here, a long-time interval vehicle speed change with time is obtained. When the long-time interval steering angle change with time and the long-time interval vehicle speed change with time are thus obtained, the amount of movement of the vehicle is calculated (S23). The movement amount of the vehicle is calculated based on the measurement time when measuring the long-time interval vehicle speed and the long-time interval vehicle speed.

  After calculating the movement amount of the vehicle, a long-time interval steering angle amplitude difference is calculated (S24). The long-time interval steering angle amplitude difference is obtained as a difference in steering angle amplitude before and after a predetermined unit time. For example, in the waveform depicting the long time interval steering angle change with time shown in FIG. 6B, the steering angle amplitude at the first measurement time t1 and the second measurement time t2 after a predetermined time has elapsed from the first time t1. A difference in steering angle amplitude is obtained as compared with the steering angle amplitude. This steering angle amplitude difference is calculated at each measurement time t1 to tn, and a long time interval steering angle amplitude difference is obtained by all the steering angle amplitude differences at each measurement time t1 to tn.

  When the long-time interval steering angle amplitude difference is obtained, the respective steering angle vectors at the respective measurement times t1 to tn are calculated (S25). The steering angle vector is a vector that connects the vertices of the steering angle amplitude when the respective steering angle amplitudes at the measurement times t1 to tn are histogrammed. For example, the first steering angle vector is a vector that connects the top of the steering angle amplitude at the first measurement time t1 and the top of the steering angle amplitude at the second measurement time. The steering angle vector is calculated based on the relationship between the steering angle amplitude difference at each time and the predetermined interval.

  Thus, when the steering angle vector at each measurement time is obtained, the curve R of the traveling path of the vehicle is calculated (S25). The curve R of the travel path of the vehicle can be calculated from the steering angle vector at each measurement time t1 to tn and the vehicle speed based on the vehicle speed signal transmitted from the vehicle speed sensor 3. Specifically, the direction and distance in which the vehicle has traveled can be obtained by multiplying the steering angle vector and vehicle speed at each measurement time t1 to tn. A travel route is obtained by connecting the travel direction and distance of the vehicle with respect to the measurement times t1 to tn. From this travel route, the curve R of the travel route of the vehicle can be obtained.

  After calculating the curve R, the arousal level decrease determination threshold value determination unit 13 determines the arousal level decrease determination threshold value corresponding to the curve R (S27). The arousal level decrease determination threshold value determination unit 13 refers to the calculated curve R in the arousal level decrease determination threshold value map, and determines the arousal level decrease determination threshold value. Thus, the arousal level decrease determination threshold value determination process is terminated.

  When the arousal level decrease determination threshold value determination process is completed, the arousal level decrease determination unit 14 performs the arousal level decrease determination process (S5). When performing the arousal level reduction determination process, the steering change power output from the steering change power calculation unit 11 is compared with the arousal level reduction determination threshold value output from the arousal level reduction determination threshold value determination unit 13. To do. Then, when the steering change power exceeds the arousal level decrease determination threshold value, it is determined that the driver's arousal level has decreased and the driver's drowsiness has increased. On the other hand, when the steering change power is equal to or lower than the arousal level decrease determination threshold value, it is determined that the driver's awake level is not decreased and the driver is in a normal state.

  Then, it is determined whether or not the driver's arousal level has decreased as a result of the arousal level decrease determination process (S6), the steering change power exceeds the arousal level decrease determination threshold value, and the driver's arousal level decreases. If it is determined that the driver's drowsiness has increased, an alarm process for transmitting an alarm signal to the alarm device 4 is performed (S7). And the process in the arousal level fall determination apparatus is complete | finished.

  On the other hand, if it is determined that the steering change power is equal to or less than the arousal level decrease determination and the driver's awakening level is not decreased and the driver is normal as a result of the awakening level decrease determination, Without performing the alarm process for transmitting the alarm signal, the process in the arousal level lowering determination device is terminated as it is.

  As described above, in the arousal level decrease determination device according to the present embodiment, the arousal level decrease determination threshold value when performing the arousal level decrease determination based on the curve R of the traveling path of the vehicle is adjusted and determined. For this reason, even when the curve R of the travel path of the vehicle changes, it is possible to accurately determine the decrease in the driver's arousal level.

  Here, the smaller the curve R of the travel path of the vehicle and the steeper curve, the greater the influence of the driver's arousal level on the steering angle change. In this regard, in the wakefulness level decrease determination device according to the present embodiment, specifically, when the curve R of the travel path of the vehicle is small and the curve is steep, the wakefulness level decrease determination threshold value is increased. Yes. For this reason, it is possible to accurately determine the reduction in the driver's arousal level according to the traveling path of the vehicle.

  Further, when calculating the steering change power, a difference signal obtained from the difference between the steering angle signal and the steering angle delay signal is used. For this reason, the state of the driver's steering change can be accurately determined. Moreover, the steering change power is an integral value in the difference signal between the steering angle signal and the steering angle delay signal during one period of the corrected steering cycle. For this reason, a driver's steering change can be judged more suitably.

  In this embodiment, the steering change power, which is the integral value of the difference signal, is used as the steering change index. However, as shown in FIG. 7, the product of the steering change power and the corrected steering cycle can be used. In this case, when the threshold value for determining the arousal level is set for the product of the steering change power and the corrected steering cycle, and the product of the steering change power and the corrected steering cycle exceeds the threshold level for determining the arousal level Therefore, it is determined that the arousal level is lowered. In addition, the arousal level decrease determination threshold value when this determination is performed is determined according to the curve R of the travel path of the vehicle. Alternatively, instead of the product of the steering change power and the corrected steering cycle, a result obtained by adding a predetermined calculation to the steering change power and the corrected steering cycle can be used as the steering change index. For example, the product of the steering change power and the corrected steering cycle is represented by a rectangle as shown in FIG. 7, but this shape may be an elliptical shape.

  Next, a second embodiment of the present invention will be described. FIG. 8 is a block configuration diagram of the arousal level decrease determination device according to the present embodiment. As shown in FIG. 8, the arousal level lowering determination apparatus according to the present embodiment includes a reference curve R storage unit 21 in which the arousal level reduction determination ECU 10 is compared with the arousal level reduction determination apparatus according to the first embodiment. And the curve R comparison unit 22 are different.

  The reference curve R storage unit 21 in the arousal level decrease determination ECU 10 according to the present embodiment stores the actual curve R of the traveling path of the vehicle as the reference curve R. Similarly to the first embodiment, the curve R calculation unit 12 uses the steering angle based on the steering angle signal transmitted from the steering angle sensor 2 and the vehicle speed based on the vehicle speed signal transmitted from the vehicle speed sensor 3. A curve R of the travel path of the vehicle is calculated. The curve R calculation unit 12 outputs a curve R signal based on the calculated curve R to the curve R comparison unit 22 together with the arousal level decrease determination threshold value determination unit 13.

  The curve R comparison unit 22 outputs the curve R signal output when the actual curve R representing the curve R in the locus of the curve on which the vehicle actually travels based on the curve R signal output from the curve R calculation unit 12 is output. The reference curve R of the traveling road at the position corresponding to the actual curve R based on is read from the reference curve R storage unit 21. The curve R comparison unit 22 compares the actual curve R based on the output curve R signal output from the curve R calculation unit 12 with the reference curve R read from the reference curve R storage unit 21, and according to the comparison result. The curve R comparison signal is output to the arousal level decrease determination unit 14.

  The arousal level reduction determination unit 14 outputs the steering change power based on the steering change power signal output from the steering change power calculation circuit 11D in the steering change power calculation unit 11 and the arousal level reduction determination threshold value determination unit 13. Based on the curve R signal output from the curve R comparison unit 22 based on the comparison result with the arousal level decrease determination threshold value, the arousal level decrease determination is performed.

  Next, a processing procedure in the wakefulness reduction determination apparatus according to the present embodiment will be described. In the wakefulness level decrease determination device according to the present embodiment, the wakefulness level decrease determination threshold value determination process (S4) and the wakefulness level decrease determination are compared with the processing procedure in the wakefulness level decrease determination process according to the first embodiment. The point that the curve R comparison process enters between (S5) and the arousal level decrease determination process are different. Hereinafter, a processing procedure in the wakefulness reduction determination apparatus according to the present embodiment will be described focusing on differences from the first embodiment.

  First, the curve R comparison process will be described. In the curve R comparison process, the curve R comparison unit 22 reads the reference curve R from the reference curve R storage unit 21 when the curve R signal is output from the curve R calculation unit 12. Next, the actual curve R based on the curve R signal output from the curve R calculation unit 12 is compared with the reference curve R read from the reference curve R storage unit 21.

  In the comparison between the actual curve R and the reference curve R, first, the smoothness of the rise of the steering angle amplitude with time in the actual curve R and the comparison curve R is compared. Here, an example of a comparison result between the actual curve R and the reference curve R is shown in FIG. In FIG. 9, the change with time of the steering angle amplitude in the actual curve R is shown as an actual curve R curve RC, and the change with time of the steering angle amplitude in the reference curve R is shown as a reference curve R curve BC. Here, the actual curve R curve RC when the driver's arousal level is low is shown as the actual curve R curve RC.

  In comparing the change over time in the steering angle amplitude between the actual curve R and the reference curve R, when the driver's arousal level is low, the steering delay rises as shown in FIG. The rise of the reference curve R curve BC becomes smoother as soon as the rise of the actual curve R curve RC than the rise of BC. After that, the one-side reference curve R curve BC has a smaller steering angle amplitude than the actual curve R curve RC, and remains as it is for a while after the vertex of the curve R is exceeded. Thereafter, the reference curve R curve BC again has a larger steering angle amplitude than the actual curve R curve RC.

  In consideration of such a tendency, the curve R comparison unit 22 compares the steering angle amplitude changes with time of the actual curve R and the reference curve R, and the rise of the actual curve R curve RC is the same as that of the reference curve R curve BC. When it is abrupt later than the rising, the driver outputs a wakefulness level decrease signal that is determined to have decreased the wakefulness level of the driver to the wakefulness level determination unit 14.

  In the arousal level reduction determination unit 14, a curve R is determined in response to the determination of the arousal level reduction based on the arousal level reduction threshold value based on the arousal level reduction threshold signal output from the arousal level reduction determination threshold value determination unit 13. The arousal level reduction determination is performed in consideration of the presence or absence of the arousal level reduction signal output from the comparison unit 22. Specifically, as a result of the determination of the arousal level reduction based on the arousal level reduction threshold signal based on the arousal level reduction threshold signal output from the arousal level reduction determination threshold value determination unit 13, the arousal level is reduced. It is determined that the driver's arousal level is reduced on the condition that the driver's arousal level reduction signal is output.

  As described above, in the arousal level decrease determination device according to the present embodiment, the comparison result between the actual curve R and the reference curve R is used. For this reason, with respect to the arousal level lowering determination apparatus according to the first embodiment, it is possible to more accurately determine the decrease in the arousal level of the driver according to the traveling path of the vehicle.

  Here, in the wakefulness level decrease determination device according to the present embodiment, the comparison result between the actual curve R and the reference curve R is used. However, the deviation of the steering angle vector obtained for each other, for example, every corrected steering cycle, is used. Further, it is possible to use a steering change power and a shift of the periodic interval distribution within a predetermined time. Here, the shift of the steering angle vector for each corrected steering cycle will be described. As shown in FIG. 10A, the actual curve R curve RC and the reference curve R curve BC are divided for each unit time, and the steering angle vector is divided. Ask for.

  Next, as shown in FIG. 10B, an actual curve R unit time vector RV which is a unit time vector of the actual curve R curve RC and a reference curve R unit time vector BV which is a unit time vector of the reference curve R curve BC. Is represented on the graph. The actual curve R unit time vector RV is obtained by shifting the steering vector so that the starting point of the steering vector obtained from the actual curve R curve RC per unit time becomes zero. The reference curve R unit time vector BV is obtained by shifting the steering vector so that the starting point of the steering vector obtained from the reference curve R curve BC per unit time becomes zero.

  Then, as shown in FIG. 10 (c), the actual curve R unit time vector RV and the reference curve R unit time vector BV are time-differentiated, respectively, to obtain an actual curve R vector deviation curve RL and a reference curve R vector deviation curve. Find BL. By comparing the actual curve R vector shift curve RL obtained here with the reference curve R vector shift curve BL, it is determined whether or not to output a wakefulness reduction signal.

  For example, the difference in maximum amplitude between the actual curve R vector shift curve RL and the reference curve R vector shift curve BL can be used as a reference when determining to output the arousal level reduction signal. In this case, when the difference in maximum amplitude between the actual curve R vector deviation curve RL and the reference curve R vector deviation curve BL exceeds a predetermined threshold value, it is determined that a wakefulness reduction signal is output. As other criteria, the amount of vector angle deviation, the number of up / down fluctuations, and the like can be used.

  Alternatively, as shown in FIG. 11, a steering change power statistical curve RS is obtained by statistically processing the steering change power for one cycle of the corrected steering cycle, and the steering change power for one cycle of the corrected steering cycle in the normal state is statistically calculated. It can also be determined whether or not to output a wakefulness reduction signal in comparison with a reference steering change power statistical curve BS obtained by processing. Here, the reference steering change power statistical curve BS can be acquired at the time of the first travel, or can be set in advance.

  As a reference when comparing the steering change power statistical curve RS and the reference steering change power statistical curve BS and determining that a wakefulness reduction signal is output, for example, when the variance in both curves exceeds a predetermined threshold, For example, when the position of the center height exceeds a predetermined threshold value.

  The preferred embodiments of the present invention have been described above, but the present invention is not limited to the above embodiments. For example, in the first embodiment, the steering change power is used as the steering change index. However, instead of the steering change power, a time corresponding to one period of the corrected steering cycle or the vibration frequency can be used.

  Here, in setting the arousal level decrease determination threshold value, for example, when the awakening level decrease determination threshold value for a straight line is 0.2 Hz, the arousal level decrease determination threshold value for a curve of 100R is set to 0. .4 Hz. Further, as the steering change index, the maximum value or average value of the amplitude in the corrected steering cycle can be used.

  Furthermore, in the above embodiment, the curve R is detected as the curve state, but the curvature of the curve can also be used. Further, in detecting the curve R, the steering angle signal and the vehicle speed signal are used, but other curve R detection means such as navigation data and a yaw rate sensor can also be used. Furthermore, it is also possible to adopt a mode in which the curve R is detected by using the curve R obtained from the steering angle signal and the vehicle speed signal and the detection result by these curve R detection means. The detection accuracy of the curve R can be improved by adopting a mode in which the curve R is detected by using the curve R obtained from the steering angle signal and the vehicle speed signal and the detection result by the curve R detection means in combination.

  DESCRIPTION OF SYMBOLS 1,10 ... Awakening degree fall determination ECU, 2 ... Steering angle sensor, 3 ... Vehicle speed sensor, 4 ... Alarm apparatus, 10 ... Awakening degree fall judgment apparatus, 11 ... Steering change power calculation part, 11A ... Delay circuit, 11B ... Difference Circuit: 11C: Zero point detection circuit, 11D: Steering change power calculation circuit, 12: Curve R calculation unit, 13: Arousal level decrease determination threshold value determination unit, 14: Arousal level decrease determination unit, 21: Reference curve R storage Part, 22 ... curve R comparison part.

Claims (6)

A wakefulness reduction determination device that determines a state of reduced wakefulness of a driver driving a vehicle based on a steering state of the vehicle,
Steering angle detection means for detecting the steering angle of the vehicle;
Steering change index detection means for detecting a steering change index in a driver driving the vehicle based on the steering angle detected by the steering angle detection means;
A curve state detecting means for detecting a curve state in the traveling path of the vehicle;
Arousal level reduction determination means for determining that the driver's arousal level is in a reduced state when the steering change index exceeds a predetermined threshold;
Based on the curve state detected by the curve state detection means, a wakefulness reduction determination threshold setting means for setting a wakefulness reduction determination threshold used by the wakefulness reduction determination means;
Equipped with a,
The steering change indicator, a steering angle signal and the awareness decrease determination device for the steering change power der wherein Rukoto an integral value of the difference signal between the steering angle delay signal during one cycle of the corrective steering cycle.   2. The wakefulness level decrease determination apparatus according to claim 1, wherein the wakefulness level decrease determination threshold value setting unit increases the wakefulness level decrease determination threshold value as the curve state is steeper. The steering change index detecting means includes
Based on the steering angle detected by the steering angle detection means, and has a steering cycle calculation means for calculating a correction steering cycle that becomes the steering change index,
The steering cycle calculation means is obtained by delaying a steering angle signal based on the steering angle detected by the steering angle detection means for a predetermined time, and delaying the steering angle signal by the steering angle signal and the delay means. Difference calculating means for calculating a difference from the delayed signal, and zero point detecting means for detecting a zero point from a change in the sign of the difference output based on the calculation result in the difference calculating means, and the zero point detecting means detected awareness decrease determination device according to claim 1 or claim 2 that to calculate the distance between the zero point as the correction steering cycle. The steering change index detecting means includes
Based on the steering angle detected by the steering angle detection means, and having a steering cycle calculation means for calculating a correction steering cycle,
The steering cycle calculating means includes a delay means for delaying the steering angle signal for a predetermined time, a difference means for calculating a difference between the detected steering angle signal and a delay signal from the delay means, and a difference output from the difference means. Zero point detecting means for detecting a zero point from the change of the sign of, and calculating the interval between the zero points detected by the zero point detecting means as the corrected steering cycle ,
Consists integral value of the difference output during one cycle of the corrective steering period, awakening according to claim 1 or claim 2 and a steering change power calculating means for calculating a steering change power serving as the steering change index Degradation determination device. Vehicle speed detecting means for detecting the vehicle speed of the vehicle,
The curve state detection unit detects a curve state on a traveling road of the vehicle based on a change with time of the steering angle detected by the steering angle detection unit and a vehicle speed detected by the vehicle speed detection unit. The awakening degree fall determination apparatus of any one of Claim 4. A wakefulness reduction determination device that determines a state of reduced wakefulness of a driver driving a vehicle based on a steering state of the vehicle,
Steering angle detection means for detecting the steering angle of the vehicle;
Steering change index detection means for detecting a steering change index in a driver driving the vehicle based on the steering angle detected by the steering angle detection means;
A curve state detecting means for detecting a curve state in the traveling path of the vehicle;
Based on a comparison between the threshold value set according to the curve state detected by the curve state detection unit and the steering change index detected by the steering change index detection unit, the driver's awakening A wakefulness decrease determination means for determining the degree;
Equipped with a,
The steering change indicator, a steering angle signal and the awareness decrease determination device for the steering change power der wherein Rukoto an integral value of the difference signal between the steering angle delay signal during one cycle of the corrective steering cycle.

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