JP2014202498A - Driving support apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a driving support apparatus configured to issue an appropriate warning about skidding due to a frozen road surface.SOLUTION: A driving support apparatus determines whether skidding has occurred or not on the basis of a difference in rotation speed of wheels, determines whether a road surface is frozen or not when the skidding is determined, and issues a warning on the skidding due to the frozen road surface when the road surface is frozen.

Description

  The present invention relates to a driving support apparatus capable of accurately determining a road surface condition and performing appropriate driving support according to the determination result.

  When driving a car in winter, for example, an operation according to road surface conditions such as snow and freezing is required. In other words, an operation corresponding to the road surface condition leads to an increase in driving safety. Specifically, by appropriately grasping the road surface condition in which slip is likely to occur and performing an operation in accordance with the road surface condition, the occurrence of slip can be suppressed and the safety of driving can be improved.

  Conventionally, automobiles have not been provided with a function for assisting in grasping the road surface condition, and the driver has grasped the road surface condition by visual observation or the like. For example, when the outside air temperature falls below a predetermined temperature (about 3 ° C.), there are some vehicles equipped with a function to call attention to freezing of the road surface, but it is difficult to accurately grasp the road surface condition that easily slips only at the outside air temperature. .

  In recent years, for example, there is a system that detects the occurrence of a slip and issues an alarm to the driver when the slip occurs. For example, there is one that detects the magnitude of the slip ratio of the wheel and issues a warning to the driver when the slip ratio is equal to or higher than a reference value (see Patent Document 1).

JP 10-217933 A

  With the technique described in Patent Document 1, an alarm can be issued to the driver when a slip occurs. However, the driver cannot determine whether the slip is due to a frozen road surface condition or due to other factors. In order to increase the safety of driving in winter, it is preferable for the driver to accurately grasp that the slip is caused by a frozen road surface condition.

  This invention is made | formed in view of such a situation, and it aims at providing the driving assistance device which can perform a precise warning with respect to the slip by the frozen road surface state.

  A first aspect of the present invention that solves the above problems is a rotation speed detection means that detects the rotation speed of each wheel of a vehicle, a road surface temperature measurement means that measures a road surface temperature, and a detection result of the rotation speed detection means. Based on the rotational speed difference calculating means for calculating the rotational speed difference based on at least the rotational speeds of the two left and right wheels, and whether or not wheel slip has occurred based on the calculation result of the rotational speed difference calculating means. A slip determination means for determining whether or not a slip has occurred by the slip determination means, a freeze determination means for determining whether or not the road surface is frozen based on the temperature of the road surface, and a road surface by the freeze determination means And a warning unit that issues a warning to the effect that a slip due to the road surface freezing has occurred when it is determined that there is freezing.

  According to a second aspect of the present invention, in the driving support device according to the first aspect, the rotation speed detection means detects the rotation speeds of all four wheels, and the rotation speed difference calculation means calculates the rotation speed of each wheel. The driving assistance apparatus is characterized in that the maximum difference among the number differences is calculated as the rotation speed difference.

  According to a third aspect of the present invention, in the driving support device according to the first or second aspect, the slip determination means determines whether or not the rotational speed difference is equal to or greater than a preset reference rotational speed difference, In the driving assistance device, it is determined that a slip has occurred when the difference is greater than or equal to the reference rotational speed difference.

  According to a fourth aspect of the present invention, in the driving support device according to the third aspect, the slip determination means is configured such that a duration time during which a rotational speed difference equal to or greater than the reference rotational speed difference has occurred is a preset reference duration time. It is further determined whether or not this is the case, and when the duration is equal to or longer than the reference duration, it is determined that a slip has occurred.

  According to a fifth aspect of the present invention, in the driving support apparatus according to the third or fourth aspect, the driving support device further includes a handle angle detecting unit that detects a handle angle of the vehicle, and the reference rotational speed difference is detected by the handle angle detecting unit. The driving support device is set based on the steering wheel angle and the road surface temperature measured by the road surface temperature measuring means.

  According to a sixth aspect of the present invention, in the driving support device according to the fifth aspect, the reference rotational speed difference is set based on the steering wheel angle, the road surface temperature, and the speed of the vehicle. It is in the driving support device.

  According to a seventh aspect of the present invention, in the driving support device according to any one of the first to sixth aspects, the warning means changes the content of the alarm according to the road surface temperature measured by the road surface temperature measuring means. There is a driving support device characterized in that.

  According to the driving support apparatus of the present invention, when a slip occurs, it can be accurately determined whether or not the slip is caused by freezing of the road surface. Therefore, by issuing a warning to that effect to the driver, the driver can perform an appropriate driving operation, and the occurrence of slip can be suppressed.

It is a figure showing a schematic structure of a driving support device concerning one embodiment of the present invention. It is a block diagram which shows schematic structure of the driving assistance device which concerns on one Embodiment of this invention. It is a flowchart which shows control of the driving assistance device which concerns on one Embodiment of this invention. It is a flowchart which shows control of the driving assistance device which concerns on one Embodiment of this invention. It is a flowchart which shows control of the driving assistance device which concerns on one Embodiment of this invention.

  Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings.

  The driving assistance device according to the present invention determines whether or not the slip generated during the traveling of the vehicle is caused by road surface freezing, and when it is caused by road surface freezing, A warning to that effect is issued.

  As shown in FIG. 1, the driving support device 10 according to the present embodiment includes a rotation speed detection sensor (rotation speed detection means) 11 that detects the rotation speed of each wheel 2 of the vehicle 1 and a road surface on which the vehicle 1 travels. A road surface temperature measuring device (road surface temperature measuring means) 12 that measures temperature, a steering wheel angle sensor (handle angle detecting means) 13 that detects a steering angle (hereinafter referred to as a steering wheel angle) of the steering wheel 3, and a driving support control unit 20 And.

  The road surface temperature measuring device 12 is provided at the front portion of the vehicle 1 and measures the temperature of the road surface in front of the vehicle 1. The method of measuring the road surface temperature by the road surface temperature measuring device 12 is not particularly limited. For example, the road surface temperature can be measured in a non-contact manner by using an infrared radiation thermometer using infrared rays. .

  The driving support control unit 20 determines the presence / absence of slip from the detection result of the rotation speed detection sensor 11, the measurement result of the road surface temperature measuring device 12, and the detection result of the handle angle sensor 13, and if necessary. Alert the driver. In the present embodiment, the driving support control unit 20 includes a rotation speed difference calculation unit 21, a slip determination unit 22, a freezing determination unit 23, and an alarm unit 24.

  The rotational speed difference calculating means 21 calculates the rotational speed difference of the wheel 2 based on the detection result of the rotational speed detection sensor 11. In the present embodiment, the rotation speed detection sensor 11 is provided corresponding to each of the four wheels 2 of the vehicle 1 and detects the rotation speed of each wheel 2. Then, the rotational speed difference calculating means 21 calculates the maximum difference among the rotational speed differences of the wheels 2 as the rotational speed difference. That is, the difference between the minimum value and the maximum value of the rotational speeds of the four wheels 2 is calculated as the rotational speed difference.

  In this embodiment, the rotational speed difference is detected based on the rotational speeds of the four wheels 2. However, the rotational speed difference may be calculated based on at least the rotational speeds of the two left and right wheels 2. In this case, it is preferable to calculate the rotational speed difference of the drive wheels.

  The slip determination means 22 determines whether or not a slip of the wheel 2 has occurred based on the “rotation speed difference” that is a calculation result by the rotation speed difference calculation means 21. Specifically, the slip determination means 22 determines whether or not the “rotational speed difference” is equal to or greater than a preset “reference rotational speed difference”. If this “rotational speed difference” is equal to or greater than the “reference rotational speed difference”, the slip determination means 22 determines that the duration time during which the rotational speed difference is greater than or equal to the reference rotational speed difference has occurred. It is further determined whether or not it is longer than the duration. And when this continuation time is more than reference | standard continuation time, it determines with slip having generate | occur | produced.

  In the present embodiment, the slip determination means 22 increases the accuracy of determination by determining whether or not slip has occurred based on the “rotational speed difference” and the “continuation time”. Even when the determination is based only on “difference”, the occurrence of slip can be determined relatively accurately.

  Here, the “reference rotational speed difference” is determined from the “handle angle” that is the detection result of the handle angle sensor 13 and the “road surface temperature” that is the measurement result by the road surface temperature measuring device 12. For example, the driving support control unit 20 stores a map that defines the relationship between the reference rotational speed difference, the steering wheel angle, and the road surface temperature, and the detection result of the steering wheel angle sensor 13 and the measurement result of the road surface temperature measuring device 12 Is determined with reference to this map. The reference rotational speed difference is smaller as the road surface temperature is lower, and is larger as the road surface temperature is higher. The smaller the handle angle, the smaller the value, and the larger the handle angle, the greater the value. On the other hand, the “reference duration” is determined by the road surface temperature, and is shorter as the road surface temperature is lower and longer as the road surface temperature is higher.

  The reference rotational speed difference may be determined in consideration of the traveling speed (vehicle speed) of the vehicle 1 together with the steering wheel angle and the road surface temperature. In this case, the reference rotational speed difference increases as the vehicle speed increases.

  The freezing determination means 23 determines the presence or absence of road surface freezing based on the road surface temperature measured by the road surface temperature measuring device 12 when the slip determination means 22 determines that slip has occurred. Specifically, the freezing determination means 23 determines that the road surface is frozen when the road surface temperature is lower than 0 ° C. (below freezing point), and determines that there is no road surface freezing when the road surface temperature is 0 ° C. or higher.

  The warning unit 24 issues a warning that the slip caused by the road surface freezing has occurred when the freezing determination unit 23 determines that the road surface is frozen. That is, when it is determined by the slip determination means 22 that the slip has occurred and the freezing determination means 23 determines that the road surface is frozen, the warning means 24 informs the driver that a slip due to the road surface freezing has occurred. An alarm is issued. For example, in this embodiment, the warning means 24 issues a warning to the driver by appropriately turning on the first to fifth warning lights 5 provided in the instrument panel 4 according to the road surface temperature or the like. Specifically, when the occurrence of slip is confirmed, the first warning lamp 5a is turned on, and if the road surface temperature is lower than 0 ° C. (if the road surface is frozen), the second warning is issued. The lamp 5b is turned on. In addition, although the road surface is not frozen, the third warning lamp 5c is turned on as a warning when there is a possibility of road surface freezing.

  The method of warning the driver by the warning means 24 is not particularly limited. For example, the warning may be issued by voice, or the warning may be issued by text or video on a monitor constituting the navigation device or the like. You may do it.

  According to the driving support device 10 of the present embodiment having such a configuration, when a slip occurs, the driver accurately determines whether the slip is caused by road surface freezing or other factors. can do.

  Hereinafter, an example of the driving support control in the driving support apparatus of the present invention will be described with reference to the flowcharts of FIGS. First, control in a state where the warning lamp 5 is not lit, that is, lighting control of the warning lamp 5 will be described with reference to FIG.

  As shown in FIG. 3, when the driving support control is started, first, the rotational speed of each wheel 2 of the vehicle 1 is detected by the rotational speed detection sensor 11 in step S1. Next, the handle angle is detected by the handle angle sensor 13 in step S2. Next, the road surface temperature is measured by the road surface temperature measuring device 12 in step S3. Next, the presence or absence of occurrence of slip is determined based on these detection results and measurement results. First, in step S4, the “rotational speed difference” is calculated from the rotational speeds of the wheels 2, and it is determined whether or not the rotational speed difference is equal to or greater than the “reference rotational speed difference”. If the rotational speed difference is greater than or equal to the reference rotational speed difference, the process proceeds to step S5, and the “continuation time” in which the rotational speed difference is greater than or equal to the reference rotational speed difference is set to a preset “reference continuous time”. It is further determined whether or not. If this duration is equal to or longer than the reference duration (step S5: Yes), it is determined that a slip has occurred (step S6). Next, in step S7, the presence or absence of road surface freezing is determined. That is, it is determined whether or not the road surface temperature is less than 0 ° C. At this time, when the road surface temperature is lower than 0 ° C. (step S7: Yes), it is determined that the road surface is frozen (step S8). When the process proceeds to step S8, it is determined that slip has occurred and road surface has been frozen, so in the next step S9, the first warning light 5a for warning the occurrence of slip and the road surface freezing is warned. The second warning lamp 5b to be turned on is turned on, and the series of processing is completed.

  If the road surface temperature is 0 ° C. or higher in step S7 (step S7: No), it is determined that there is no road surface freezing (step S10). When the process proceeds to step S10, it is determined that slip has occurred and it is determined that the road surface has not been frozen. Therefore, in the next step S10, only the first warning lamp 5a that warns of the occurrence of slip is lit and a series of operations are performed. Terminate the process.

  Further, when the rotational speed difference is less than the reference rotational speed difference at step S4 (step S4: No) and when the duration time is less than the reference duration time at step S5 (step S5: No), slip has occurred. It is determined that there is not (step S12), and the series of processing ends without turning on the warning lamp 5.

  Next, the control for turning off the warning light 5, specifically, the control when the first warning light 5a and the second warning light 5b are turned on in step S9 will be described with reference to FIG. The description of the same steps is omitted. First, even when the first warning light 5a and the second warning light 5b are lit, it is determined whether or not slip has occurred in steps S1 to S5 as described above. In step S5, when the duration is equal to or longer than the reference duration, that is, when a slip has occurred (step S5: Yes), the first warning lamp 5a and the second warning lamp 5b are continuously turned on. The process is terminated.

  On the other hand, if the duration is less than the reference duration in step S5, that is, if no slip has occurred (step S5: No), the process proceeds to step S21, and the state in which no slip has occurred is equal to or longer than the predetermined period T1. It is determined whether or not it continues. If this state continues for a predetermined period T1 or more (step S21: Yes), the first warning light 5a and the second warning light 5b are turned off, and the third is a warning of road surface freezing. Is turned on (step S22). Thereafter, when the road surface temperature becomes equal to or higher than a preset threshold value (step S23: Yes), the third warning lamp 5c is turned off (step S24), and the series of processes is terminated.

  FIG. 5 shows the turn-off control when the first warning lamp 5a is turned on in step S10. In this example, as shown in FIG. 5, when it is determined in step S4 whether or not the rotational speed difference is greater than or equal to the reference rotational speed difference, if the rotational speed difference is greater than or equal to the reference rotational speed difference (step S4: Yes), the process is terminated while the first warning lamp 5a is kept on. On the other hand, when the rotational speed difference is less than the reference rotational speed difference in step S4 (step S4: No), the process proceeds to step S25, and the state where the rotational speed difference is less than the reference rotational speed difference continues for a predetermined period T2 or more. It is determined whether or not. If this state continues for a predetermined period T2 or longer (step S25: Yes), the first warning lamp 5a is turned off in step S26, and the series of processes is terminated. When it does not continue for the predetermined period T2 or more (step S25: No), the process is ended while the first warning lamp 5a is kept on.

  As described above, according to the driving assistance apparatus 10 of the present embodiment, when a slip occurs, it can be accurately determined whether or not the slip is caused by freezing of the road surface. Therefore, by issuing a warning to that effect to the driver, the driver can perform an appropriate driving operation, and the occurrence of slip can be suppressed.

  The present invention is not limited to the above-described embodiment, and can be appropriately changed without departing from the spirit of the invention.

DESCRIPTION OF SYMBOLS 1 Vehicle 2 Wheel 3 Steering wheel 4 Instrument panel 5 Warning light 10 Driving assistance apparatus 11 Rotational speed detection sensor 12 Road surface temperature measuring apparatus 13 Handle angle sensor 20 Driving assistance control part 21 Rotational speed difference calculation means 22 Slip determination means 23 Freezing determination Means 24 Alarm means

Claims (7)

A rotational speed detection means for detecting the rotational speed of each wheel of the vehicle;
Road surface temperature measuring means for measuring the temperature of the road surface;
Based on the detection result of the rotation speed detection means, a rotation speed difference calculation means for calculating a rotation speed difference based on at least the rotation speeds of the two left and right wheels;
Slip determining means for determining whether or not wheel slip has occurred based on the calculation result of the rotational speed difference calculating means;
Freezing determination means for determining the presence or absence of road surface freezing based on the temperature of the road surface when the slip determination means determines that slip has occurred,
An alarm means for issuing an alarm to the effect that a slip caused by the road surface freezing has occurred when the freezing determination means determines that the road surface is frozen;
A driving support apparatus comprising: The driving support device according to claim 1,
The rotational speed detection means detects the rotational speeds of all four wheels,
The said rotation speed difference calculation means calculates the largest difference among the rotation speed differences of each wheel as said rotation speed difference, The driving assistance device characterized by the above-mentioned. In the driving assistance device according to claim 1 or 2,
The slip determination means determines whether or not the rotational speed difference is greater than or equal to a preset reference rotational speed difference, and determines that slip has occurred when the rotational speed difference is greater than or equal to a reference rotational speed difference. Driving assistance device. In the driving assistance device according to claim 3,
The slip determination means further determines whether or not a duration time during which a rotational speed difference equal to or greater than the reference rotational speed difference has occurred is greater than or equal to a preset reference duration time, and the duration time is the reference duration time. When it is above, it determines with the slip having generate | occur | produced, The driving assistance device characterized by the above-mentioned. In the driving assistance device according to claim 3 or 4,
A steering wheel angle detecting means for detecting a steering wheel angle of the vehicle;
The driving support device according to claim 1, wherein the reference rotational speed difference is set based on a steering wheel angle detected by the steering wheel angle detection unit and a road surface temperature measured by the road surface temperature measurement unit. The driving support device according to claim 5,
The reference assistance speed difference is set based on the steering wheel angle, the road surface temperature, and the speed of the vehicle. In the driving assistance device according to any one of claims 1 to 6,
The said warning means changes the content of a warning according to the road surface temperature measured by the said road surface temperature measurement means, The driving assistance apparatus characterized by the above-mentioned.

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