JP2001273594A - Device for monitoring driving operation for vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To correctly detect the unstable state of driving operation under any traveling condition containing a curved road. SOLUTION: A steering angle estimating value θn-hat in the case of assumption that a driver is concentrated in the driving operation is calculated based on a repeatedly detected steering angle detection value θn, a steering angle estimating value θn-hat' in the case of assumption that the driver is concentrated in the driving operation is calculated based on a forward vehicle direction detection value ϕn which is repeatedly detected in forward vehicle follow-up traveling control and, then, the final steering angle estimating value θn-hat" is decided from the steering angle estimating values θn-hat and O n-hat' by considering an inter-vehicle distance dn till the forward vehicle. A difference between the final value θn-hat" and the steering angle detection value θn is calculated to detect the unstable state of the driving operation based on the steep degree of a steering difference distribution. Thereafter, the steering angle estimating value in the case of assuming that the driver is concentrated in the driving operation is correctly obtained even concerning the curved road so that the unstable state of the driving operation is correctly detected under any traveling condition comprising the curved road.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a device for monitoring a driving operation of a driver.

[0002]

2. Description of the Related Art In order to detect that a driving operation is in an unstable state due to attention being paid to work other than driving as well as drowsy driving, a driver is required to detect a steering angle based on past steering angle detection values. Estimate the current steering angle when it is assumed that attention is focused on the driving operation, detect the steering error between the estimated steering angle and the current actual detected steering angle, and determine the steep distribution of the steering error. 2. Description of the Related Art A vehicular driving operation monitoring device that detects an unstable driving operation based on degrees is known (for example, see Japanese Patent Application Laid-Open No. H11-227491).

[0003] In this vehicle driving operation monitoring device, the steering error increases when the vehicle is traveling on a curved road. May be mistaken as being in an unstable state. Therefore, it is apparent that the steering error is reduced under the condition that the curvature of the road is small and the steering operation is normal and the change in the steering angle is small and smooth, that is, the vehicle is running on a highway at a substantially constant speed. Is detected, and an unstable state of the driving operation is detected based on the steepness of the steering error distribution.

[0004]

However, in the conventional vehicle driving operation monitoring apparatus, even when the vehicle is traveling on a curved road of a highway at a substantially constant speed, it is assumed that the vehicle is traveling on a straight road. Since the unstable operation is detected, there is a problem that the detection accuracy is deteriorated.

Further, since the detection condition is that the vehicle is traveling on a high speed road at a substantially constant speed, there is a problem that the driving operation cannot be monitored when traveling on a curved road of a general road.

SUMMARY OF THE INVENTION It is an object of the present invention to accurately detect an unstable driving operation under any driving conditions including a curved road.

[0007]

The present invention will be described with reference to FIG. 8 showing the configuration of one embodiment. (1) The invention of claim 1 is a steering angle detecting means for repeatedly detecting a steering angle θ. 2 and the detected steering angle θn (n = ···,
n-3, n-2, n-1, n), based on the assumption that the driver concentrates on the driving operation, the estimated steering angle θn-
a steering angle estimating means A-1 for calculating hat, an obstacle detecting means 8 for repeatedly detecting a direction φn and a distance dn of an obstacle existing ahead of the vehicle from the own vehicle, and a detected direction value of the obstacle φn
A preceding vehicle on the own vehicle traveling lane based on the detected vehicle distance and the distance detection value dn, and controls the vehicle so as to follow the preceding vehicle while maintaining a constant inter-vehicle distance.
And the estimated steering angle θn-ha when it is assumed that the driver is concentrated on the driving operation based on the detected direction value φn of the preceding vehicle.
The steering angle estimating means B-1 for calculating t 'and the steering angle estimated values θn-hat and θn- in consideration of the following distance dn to the preceding vehicle.
a steering angle estimation value determining means 1 for determining a final steering angle estimation value θn-hat ”from hat ′, and a final steering angle estimation value θn-ha
a steering error calculating means for calculating an error between t "and the detected steering angle θn; and an unstable state detecting means for detecting an unstable state of the driving operation based on the steepness of the distribution of the steering error. (2) In the vehicle driving operation monitoring apparatus according to the second aspect, the steering angle estimation value determining means 1 controls the inter-vehicle distance dn to the preceding vehicle.
Is shorter, the weight for the estimated steering angle θn-hat ′ is increased, and the final estimated steering angle θn-hat ”is determined by weighted averaging of the estimated steering angles θn-hat and θn-hat ′. (3) In the vehicle driving operation monitoring device of the third aspect, the absolute value of the difference between the estimated steering angle θn-hat and θn-hat ′ is a predetermined value θo.
In such a case, the estimated steering angles θn-hat and θn-hat ′ are not used for detecting the unstable state of the driving operation. (4) The invention according to claim 4 is based on obstacle detection means 8 for repeatedly detecting the direction and distance of an obstacle existing ahead of the vehicle from the own vehicle, and the detected direction and distance of the obstacle. A preceding vehicle following the preceding vehicle on the own vehicle traveling lane, and controlling the vehicle so as to follow the preceding vehicle while maintaining a constant inter-vehicle distance; and driving based on a direction detection value of the preceding vehicle. Steering angle estimating means 1 for calculating a steering angle estimated value when it is assumed that the driver is concentrated on driving operation, steering angle detecting means 2 for repeatedly detecting the steering angle, steering angle estimated value and steering angle detected value Error calculating means 1 for calculating an error with the steering wheel
And unstable state detecting means 1 for detecting an unstable state of the driving operation based on the steepness of the distribution of the steering error, thereby achieving the above object.

In the section of the means for solving the above-mentioned problems, a diagram of an embodiment is used for easy understanding of the description, but the present invention is not limited to the embodiment. .

[0009]

(1) According to the first aspect of the present invention, the estimated steering angle θ when the driver is assumed to be concentrated on the driving operation based on the repeatedly detected steering angle θn.
While calculating n-hat, the estimated steering angle θn-hat when the driver is assumed to be concentrated on the driving operation based on the detected direction value φn of the preceding vehicle repeatedly detected in the preceding vehicle following travel control. To determine the final estimated steering angle θn-hat "from the estimated steering angles θn-hat and θn-hat 'in consideration of the inter-vehicle distance dn to the preceding vehicle. Then, the final steering is performed. Angle estimation value θn-hat ”and steering angle detection value θn
Error is calculated, and the unstable state of the driving operation is detected based on the steepness of the distribution of the steering error, so it is assumed that the driver is concentrated on the driving operation even on a curved road It is possible to accurately obtain the estimated steering angle of the vehicle, and to accurately detect the unstable state of the driving operation under any running conditions including a curved road. (2) According to the second aspect of the present invention, the shorter the inter-vehicle distance dn to the preceding vehicle, the greater the weight for the estimated steering angle θn-hat 'is set, and the estimated steering angle θn-hat and θn-hat' are calculated. The final estimated steering angle θn-hat ”is determined by weighted averaging. In general, the shorter the inter-vehicle distance, the larger the required steering angle than the actual required steering angle. When the distance is short, the driver may erroneously recognize that the driving operation is in an unstable state from the detected large steering angle even though the driver concentrates his attention on driving. According to (3), it is possible to avoid erroneous recognition that occurs when the inter-vehicle distance is short, and to accurately detect an unstable state of the driving operation regardless of the inter-vehicle distance. According to the estimated steering angle θn-ha
When the absolute value of the difference between t and θn-hat 'is equal to or larger than the predetermined value θo, the estimated steering angles θn-hat and θn-hat' are not used for detecting the unstable state of the driving operation. . In general, if there is an interruption of another vehicle between the preceding vehicle and the preceding vehicle while the vehicle is following the preceding vehicle, or if there is a change in the vehicle to be followed, the direction detection value φn of the preceding vehicle may greatly change. In such a case, it is impossible to obtain accurate steering angle detection values θn-hat and θn-hat ′, and the detection accuracy of the unstable driving operation state is reduced. According to the third aspect of the present invention, the estimated steering angles θn-hat and θn-hat ′ when the direction detection value φn of the preceding vehicle greatly changes are not used for detecting the unstable state of the driving operation. The detection accuracy of the unstable operation state is not reduced. (4) According to the invention of claim 4, the steering angle estimation value when the driver is assumed to be concentrated on the driving operation based on the direction detection value of the preceding vehicle repeatedly detected in the preceding vehicle following travel control. And the error between the estimated steering angle and the detected steering angle is calculated, and the unstable state of the driving operation is detected based on the steepness of the distribution of the steering error.
Even on a curved road, it is possible to accurately obtain a steering angle estimated value assuming that the driver is concentrated on driving operation,
Under any driving conditions including a curved road, the unstable state of the driving operation can be accurately detected.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In the present invention, the degree of an unstable driving operation, that is, the degree of instability of a driver is detected by the steering entropy method. Before describing the embodiments of the present invention, the steering entropy method will be described first.

<< Outline of Steering Entropy Method >> The steering entropy method is a method of calculating the degree of instability of the driving operation based on the smoothness of the steering operation (steering angle). When the driver is not focused on the driving operation due to a load other than the driving operation (hereinafter referred to as a loaded state or a loaded state), the driver does not perform any operation other than the driving operation. In a state in which attention is focused on the driving operation (hereinafter, referred to as a no-load state or a no-load state), a period during which steering is not performed is longer, and a large steering angle error is accumulated. Therefore, the corrected steering amount when the driver returns to the caution is increased, and the degree of the driving operation is increased when the time series data of the steering angle is viewed. The steering entropy method focuses on this characteristic, and uses an α value and a steering angle entropy Hp value calculated based on the α value as a characteristic value. The α value itself represents the degree of instability of the driver, but is used here as a reference value for calculating the steering angle entropy Hp value which is not affected by the skill and habit of the driver. Then, the degree of instability of the driver is detected based on the steering angle entropy Hp value.

<< Regarding the α Value >> The α value is an estimation of the steering error within a certain period of time based on the time series data of the steering angle, that is, the steering angle when it is assumed that the driver concentrates his or her attention on the driving operation. The difference between the value and the actual steering angle is obtained, the distribution (variation) of the steering error is measured, and the 90% tile value (the range of the distribution including 90% of the steering error) is calculated. The measurement of the α value is performed without load, and the obtained α
The value is a reference value of the instability of the driver at that time. The α value decreases when the steering operation is smooth and stable, and increases when the steering operation is unstable. Also, the smaller the driving skill of the driver and the more stable the steering, the smaller the value. On the contrary, the lower the driving skill of the driver, the larger the steering operation becomes jerky and unstable. The α value also differs depending on the habit of the driver. Further, even the same driver changes due to a change in physical condition or a change in driving skill.

<< Regarding Hp Value >> The Hp value is the steering angle entropy and represents the ambiguity (uncertainty) of the distribution of the steering error. The Hp value is obtained by dividing the distribution of the steering error into nine sections according to the α value, and the distribution ratio (distribution probability) in each section.
Is calculated as the entropy of Like the α value, the Hp value decreases when the steering operation is smooth and stable, and increases when the steering operation is unstable. Hp
The value is corrected by the α value and can be used as a driver instability that is not affected by the skill or habit of the driver.
That is, for the same load, almost the same value is shown regardless of the skill or habit of the driver. Therefore, it can be said that this is an unprecedented revolutionary parameter indicating the degree of instability of the driver.

Next, a description will be given of a method of detecting an unstable driving operation state by the steering entropy method. First, Table 1 shows special symbols and their names used in this specification.

[Table 1] In Table 1, the smooth value θn-tilde of the steering angle is a steering angle in which the influence of quantization noise is reduced. The estimated steering angle θn-hat is a value obtained by estimating the steering angle at the time of sampling, assuming that the steering is smoothly operated.

The estimated steering angle θn-hat is a steering angle smooth value θn
Obtained by performing a second-order Taylor expansion on -tilde.
That is,

(Equation 1) In Expression 1, tn is a sampling time of the steering angle θn, and the smooth value θn-tilde is an average value of three adjacent steering angles θn in order to reduce the influence of quantization noise.

(Equation 2) In Equation 2, l is within 150 ms when the calculation time interval of the smooth value θn-tilde used for the calculation of the estimated value θn-hat is 150 ms, that is, the minimum time interval that can be intermittently operated by a human in manual operation. Included in the steering angle θn
Represents the number of samples. If the sampling interval of the steering angle θn is Ts,

(Equation 3) Further, the values of k = 1, 2, 3 are taken, and 1 is obtained by (k * l).
The smooth value θn-tilde can be obtained based on the steering angles at 50 ms intervals and a total of three steering angles θn adjacent thereto. Therefore, the estimated value θn-hat calculated based on the smooth value θn-tilde is calculated based on the steering angles θ obtained at intervals of substantially 150 ms.

In the above-mentioned Japanese Patent Application Laid-Open No. 11-227491, as shown in FIG.
Three past steering angles θn-3, θn-2, θ detected for each
Based on n-1, the steering angle estimation value θn-hat at the current steering angle sampling time tn when assuming that the driver concentrates his or her attention on the driving operation by the above formulas 1 to 3 is obtained, and the current The difference from the actual detected steering angle θn is defined as a steering error en.

(Equation 4)

However, in the method of calculating the steering error en, the steering error en becomes large when the vehicle travels on a curved road as shown in FIG. That is, when the current steering angle estimated value θn-hat is obtained based on the past steering angle detection values on the straight road up to the point A, the point becomes the point B. However, since the vehicle is actually traveling at the point C on the curved road, a large steering The angle θn is detected, and the steering error en increases.

Therefore, in this embodiment, a preceding vehicle following travel control device that recognizes a preceding vehicle and follows the preceding vehicle while maintaining a constant inter-vehicle distance is used, and the direction of the preceding vehicle detected by the preceding vehicle following travel control device is used. Based on the distance, the estimated steering angle θn-
hat 'is obtained, and an accurate steering error en is calculated even when the vehicle is traveling on a curved road to improve the detection accuracy of the unstable driving operation state.

The traveling control device for following the preceding vehicle includes a radar sensor, and as shown in FIG. 3, can detect the direction φ of the obstacle existing in front of the vehicle and the distance d to the obstacle. Based on these detection results, the preceding vehicle on the own lane or on the adjacent lane can be specified. Here, the obstacle direction φ is an angle from the vehicle center line in the vehicle longitudinal direction.

Now, as shown in FIG. 3, the vehicle is traveling on a curved road, and at the previous steering angle sampling time tn-1, the direction φn-1 and the distance dn-1 of the preceding vehicle are detected, and the current steering is performed. Assuming that the direction φn and the distance dn of the preceding vehicle are detected at the angular sampling time tn, the change Δφ in the traveling direction of the vehicle from the previous sampling time tn-1 to the current sampling time tn.
Is

Δφ = φn−1−φn (5) Since there was a change in the traveling direction Δφ between the previous sampling time tn-1 and the current sampling time tn, a change in the traveling direction from the steering angle θn-1 at the previous sampling time tn-1 occurred at the current sampling time tn. It suffices if there is a steering angle change Δθ corresponding to Δφ.

As shown in FIG. 4, the estimated steering angle θn-ha at the current sampling time tn estimated based on the direction and distance information of the preceding vehicle from the preceding vehicle following travel control device.
t ′ is a value obtained by adding the steering angle change Δθ to the steering angle θn−1 at the previous sampling time tn−1.

(Equation 6) Since the estimated steering angle θn-hat ′ does not include the estimation error on the curved road as described above, the estimated steering angle θ calculated based on the past detected steering angle by the Taylor expansion.
More accurate than n-hat.

In this embodiment, the steering angle estimation value θn-hat calculated based on the past steering angle detection value based on the former tailor expansion and the latter vehicle direction φ from the preceding vehicle following travel control device. Steering angle estimated value θn-ha calculated based on the
Based on t ′, the final estimated steering angle θn-hat ”is determined.

First, when the absolute value of the difference between the estimated steering angle θn-hat 'and θn-hat is equal to or greater than a predetermined value θo,

(Equation 7) When the vehicle satisfies the following condition, another vehicle C interrupts the preceding vehicle B to be controlled as shown in FIG. 5A, or the preceding vehicle B to be controlled following is changed to D as shown in FIG. 5B. For example, when it is determined that the direction φ of the preceding vehicle has changed greatly, the steering angle estimation values θn-hat and θn-hat ′ obtained this time are not used in the process of detecting the unstable driving operation state. Here, when a predetermined number or more of the total number of sample data satisfies Equation 7, it is determined that the direction φ of the preceding vehicle has significantly changed.

On the other hand, when the absolute value of the difference between the estimated steering angle values θn-hat ′ and θn-hat is less than the predetermined value θo, the estimated steering angle values θn-hat ′ and θn-hat are calculated using the correction coefficient Kn. Weighted and final steering angle estimated value θn-ha by weighted averaging
t ”is calculated.

(Equation 8) In Equation 8, Kn is the inter-vehicle distance dn as shown in FIG.
Is a correction coefficient set according to. Kn changes in accordance with the inter-vehicle distance dn, and becomes 1 when the inter-vehicle distance dn is equal to or less than a predetermined value, and conversely becomes 0 when the inter-vehicle distance dn is equal to or more than the predetermined value.

As shown in FIG. 7A, when traveling following the preceding vehicle, the occupant tends to perform smaller steering with respect to the direction change Δφ of the preceding vehicle as the inter-vehicle distance d from the preceding vehicle increases. is there. Conversely, as shown in FIG. 7B, the shorter the inter-vehicle distance d to the preceding vehicle, the more the steering tends to be performed with respect to the direction change Δφ of the preceding vehicle. In other words, shorter inter-vehicle distances tend to steer larger than actually required steering angles, so when the inter-vehicle distance is shorter, it is detected even though the driver concentrates his attention on driving. It is erroneously recognized that the driving operation is unstable due to the large steering angle.

Therefore, in this embodiment, the inter-vehicle distance dn
And the inter-vehicle distance dn using a correction coefficient Kn set in advance in accordance with
Is longer, the smaller the correction coefficient Kn is set, and the estimated steering angle θ obtained from the past detected steering angle by Taylor expansion
Weight the n-hat heavily. Conversely, a larger correction coefficient Kn is set as the inter-vehicle distance dn is shorter, and the estimated steering angle θ obtained from the preceding vehicle direction φ from the preceding vehicle following travel control device.
Weight the n-hat 'heavily. As described above, the final estimated steering angle θn is determined in consideration of the inter-vehicle distance dn to the preceding vehicle.
By determining "-hat", an accurate steering angle estimated value can be obtained.

With the above procedure, the final estimated steering angle θn-ha
After calculating "t", the steering error en is calculated in the following procedure.
First, a steering error en is obtained in a no-load state, and based on the distribution, the steering angle en is divided into nine sections b1 to b1 as shown in Table 2.
Divide into b9.

[Table 2] Here, the α value is such that 90% of the steering error en is in the section [−α,
α]. Since the driving skills are different for each driver and have a habit, the division bi must be set for each driver.

Next, the steering error e in the normal running state
n 'is obtained, and these steering errors en' during normal running are divided according to the categories b1 to b9 based on the α value at no load. The probability Pi that the steering error en 'is included in the section bi is obtained by dividing the frequency of the section bi by all the frequencies. The steering angle entropy Hp value in the normal traveling state is defined by the following equation.

(Equation 9) Here, the subscript p of “Hp” indicates that the steering angle entropy is a probability distribution P,

(Equation 10) To follow.

The steering angle entropy Hp value is equal to the steering error en '.
Is calculated using a logarithm with a base of 9 so that Hp becomes 1 when the steering error en 'is equally included in each section bi. Since the three sections b4 to b6 at the center of the distribution of the steering error en are set so that 90% of the total frequency is included, the Hp value does not become 1 in the no-load state.

The smaller the steering angle entropy Hp value, the steeper the distribution of the steering error en 'during normal running, and the distribution of the steering error en' is within a certain range. This indicates that the steering operation is performed smoothly and the driving operation is in a stable state. Conversely, the steering angle entropy H
As the p-value increases, the steepness of the distribution of the steering error en 'decreases, and the distribution of the steering error en' varies. this is,
Indicates that the steering operation is shaky and the driving operation is in an unstable state.

When the driver performs a task other than the driving operation and enters a loaded state, the steering angle entropy Hp becomes larger than when no load is applied.
The value increases. Therefore, when the steering angle entropy Hp value during normal traveling exceeds a preset reference value, the driving operation becomes unstable because the driver falls asleep or is distracted by work other than driving. It is determined that it is in the state. As the determination reference value for the steering angle entropy Hp value, an unstable Hp value statistically obtained by a previous experiment is set.

FIG. 8 is a diagram showing the configuration of one embodiment. The driving operation monitoring device for a vehicle according to one embodiment is mainly configured by an arithmetic and control unit 1. The arithmetic and control unit 1 includes a microcomputer and peripheral components such as an AD converter and a memory. The arithmetic and control unit 1 executes a control program, which will be described later, to detect the degree of instability of the driver, and performs various kinds of corresponding processing for concentrating attention on driving. Do. The arithmetic and control unit 1 includes a steering angle sensor 2, a vehicle speed sensor 3, a display 4, a speaker 5, an AVCN (Audio, Visual, Communication, Navigatio).
n) The equipment 6, the preceding vehicle following travel control device 7, and the like are connected.

The steering angle sensor 2 calculates the steering angle θ of the steering.
And the vehicle speed sensor 3 detects the traveling speed V. The display 4 is provided with an operation touch panel, displays the control status of the AVCN device 6 and the like, and enables the operation of the air conditioner, the operation of the navigation device, the operation of the vehicle-mounted telephone, the operation of the audiovisual device, and the like.
The speaker 5 can be used for various broadcasts such as AVCN equipment 6,
An alarm is issued when an unstable driving operation is detected. The AVCN device 6 is a vehicle-mounted audio / visual device, a telephone, a navigation device, or the like.

The preceding vehicle following travel control device 7 is a device for following the preceding vehicle on the own vehicle traveling lane while keeping a constant inter-vehicle distance, and has a radar sensor 8. The radar sensor 8 scans the fan-shaped laser beam left and right by a drive mechanism (not shown) while emitting a fan-shaped laser beam in the direction perpendicular to the road surface toward the front of the vehicle. The fan-shaped laser beam has a spread of about 3 degrees in the direction perpendicular to the road surface in order to respond to changes in vehicle attitude due to the number of passengers and loading, and also responds to changes in the road shape ahead of the vehicle such as curved roads and the number of lanes. Therefore, scanning is performed in a range of approximately 12 degrees on the left and right.

The laser beam emitted from the light emitting section of the radar sensor 8 is reflected by a reflector of the preceding vehicle and received by the light receiving section. The radar sensor 8 detects the distance d to the front obstacle based on the time difference of the reflected light from light emission to light reception, and detects the direction φ of the obstacle from the angle of the reflected light with respect to the vehicle center line in the front-rear direction of the vehicle. And sends these data d and φ to the preceding vehicle following travel control device 7. The preceding vehicle following travel control device 7 identifies the preceding vehicle on the own vehicle traveling lane based on the direction φ of the preceding vehicle detected by the radar sensor 8 and the following distance d, and maintains a certain following distance to the preceding vehicle. While following the vehicle, the engine, transmission, and braking device (not shown) of the vehicle are integrally controlled.

The type of the radar sensor 8 and the method of detecting an obstacle are not limited to the present embodiment.

FIGS. 9 to 14 are flowcharts showing a control program executed by the arithmetic and control unit 1. FIG. The operation of the embodiment will be described with reference to these flowcharts.

FIG. 9 is a flowchart showing an IGN-on program for calculating the α value at no load. When the ignition key switch of the vehicle is set to the ON position, the arithmetic and control unit 1 starts executing the control program. In step 1, it is confirmed by the preceding vehicle following travel control device 7 whether or not the following vehicle on the own vehicle traveling lane is under following traveling control. In step 2, a no-load α value calculation routine shown in FIG. 10 is executed.

The method of calculating the no-load α value will be described with reference to the flowchart shown in FIG. The calculation of the α value at no load is executed when the following control is performed for the preceding vehicle. In step 11, the steering angle θn is collected from the steering angle sensor 2 at a sampling interval Ts by a predetermined number or more.
Here, the sampling interval Ts is, for example, 50 ms. In the following step 12, the direction φn of the preceding vehicle and the inter-vehicle distance dn to the preceding vehicle are collected from the preceding vehicle following travel control device 7.

In step 13, a smooth value θn-tilde is calculated by the above equation 2 based on three adjacent steering angles θn at intervals of 150 ms. That is,

[Equation 11] Then, the steering angle estimation value θn-hat is calculated by the Taylor expansion shown in Expression 1. That is,

(Equation 12)

In step 14, based on the preceding vehicle direction φ from the preceding vehicle following travel control device 7, the steering angle estimation value θn-hat 'is calculated by the equation (6). In the following step 15,
In order to eliminate the influence of the change in the preceding vehicle direction φ due to the interruption during the preceding vehicle following running control or the change of the following vehicle, it is confirmed whether or not the above-mentioned formula 7 is satisfied. The absolute value of the difference between the estimated steering angle θn-hat 'and θn-hat is a predetermined value θ
If it is greater than or equal to o, it is determined that the preceding vehicle direction φ has changed significantly due to interruption during the preceding vehicle following travel or change of the vehicle to be followed, and the steering angle estimation values θn-hat, θn obtained this time
-hat 'is not used for the detection of unstable driving operation,
Return to the program.

If the absolute value of the difference between the estimated steering angle θn-hat 'and θn-hat is less than the predetermined value θo, the process proceeds to step 16;
Referring to the map data shown in FIG.
A correction coefficient Kn corresponding to n is determined. In step 17, the steering angle estimated value θn-hat calculated based on the past steering angle detected value by Taylor expansion and the steering angle estimated value θn- calculated based on the preceding vehicle direction φ from the preceding vehicle following control device 7. hat ′ is weighted by the correction coefficient Kn, and the final estimated steering angle θn-hat ″ is calculated by the above equation (8).

In step 18, the steering error e is calculated by the following equation.
Calculate n.

(Equation 13) Next, at step 19, a steering error e is set for each predetermined steering error.
Count the frequency of n. Here, the predetermined steering error is determined in consideration of the resolution of the steering angle sensor 2. In this embodiment, as shown in Table 3, the steering error en is set every 0.001 rad.
Classify.

[Table 3] FIG. 11 shows a distribution example of the frequency of the steering error en.

In step 20, the α calculation routine shown in FIG. 12 is executed to determine the α value at no load. FIG.
In step 2 of FIG. 2, it is determined whether or not the probability of the frequency T0.000 at the steering error en = 0.000 rad with respect to the total frequency of all the steering errors is 90% or more. If the determination is affirmative, the routine proceeds to step 32, where the α value at no load is set to 0.
000 [rad]. On the other hand, if the determination is negative, the process proceeds to step 33, where the frequency of the steering error en from -0.001 rad to +0.001 rad (T0.000 + T0.001 + T-0.001)
It is determined whether the probability of all the steering errors with respect to all frequencies is 90% or more. If the determination is affirmative, the routine proceeds to step 34, where the α value at no load is set to 0.001 [rad]. If the determination is negative, the process proceeds to step 35, where -0.
Frequency of steering error en from 002rad to + 0.002rad (T0.0
(00 + T0.001 + T-0.001 + T0.002 + T-0.002) It is determined whether or not the probability of all the steering errors with respect to all frequencies is 90% or more. If the determination is affirmative, the routine proceeds to step 36, where the α value at no load is set to 0.002 [rad]. Hereinafter, similarly, the steering error range is expanded, and a steering error e of 90% is obtained.
An α value including n ′ is found out, and is set as the α value at no load.

After calculating the α value at no load, the process returns to step 3 in FIG. 9, and the calculated α value at no load becomes the abnormal value α.
It is checked whether or not k is exceeded, and if it is not exceeded, the process proceeds to step 5 and the calculated α value is set to the α value at no load. On the other hand, if it exceeds the abnormal value αk, step 4
Then, the statistical value αo is set to the α value at the time of no load.

In this embodiment, the ignition key
Each time the switch is set to the ON position, the α value is updated on the condition that the vehicle is following the preceding vehicle. As a result, the α value for each driver can be calculated, and the α value excluding the influence of changes in driving skills and physical condition over time can be calculated for the same driver.

However, it is conceivable that the driver is in an abnormal state after the ignition is turned on, the degree of instability of the driver is high, and the α value at no load cannot be measured. Therefore,
The α value at the time of no load, that is, the statistical value αo, and the α value in the clearly unstable state, that is, the abnormal value αk are obtained by a preliminary experiment, and the α value at the time of no load calculated after the ignition is turned on Is compared with the abnormal value αk. If the calculated α value at the time of no load exceeds the abnormal value αk, the calculated α value is discarded and the statistical value αo is used as the α value at the time of no load. As a result, it is possible to avoid that the steering entropy is calculated based on the α value at the time of abnormal no-load, and erroneous determination is made.

After setting the α value at the time of no load, the routine proceeds to step 6, where a timer interrupt for starting a routine for calculating the steering angle entropy Hp value is permitted. In step 7, it is checked whether the ignition key switch has been turned off. If the ignition key switch has been turned off, the process proceeds to step 8, where the α value at no load is reset. In a succeeding step 9, the timer interruption is disabled and the process is terminated.

When the α value at the time of no load is determined, the time series data of the steering angle θn is measured on the condition that the vehicle is following the preceding vehicle, and the steering error en ′ of the steering angle θn is determined by the method described above. Calculate. Next, the steering error en 'obtained as a result of the calculation is divided into nine sections b1 to b9 based on the α value when no load is applied.
The probability Pi of i is obtained, and the steering angle entropy Hp value is calculated. The calculated Hp value is compared with an Hp value in an unstable operation state (hereinafter referred to as an abnormal value Hpk) statistically obtained by a preliminary experiment, and when the Hp value exceeds the abnormal value Hpk, It is determined that the driver is in an unstable state.

As described above, since the timer interrupt is permitted in step 6 of FIG. 9 after the determination of the α value at the time of no load, the steering angle entropy Hp value shown in FIG. 13 is calculated every predetermined time. Is executed.

In step 41 of FIG. 13, it is checked whether the vehicle is following the preceding vehicle. If the calculation condition of the Hp value is satisfied, the process proceeds to step 42. If the calculation condition is not satisfied, the Hp value is not calculated. The processing ends. In step 42, the Hp calculation routine shown in FIG. 14 is executed to calculate the Hp value.

According to the flowchart of FIG.
The method of calculating the value will be described. The calculation of the Hp value is executed when the following control is performed for the preceding vehicle. In step 51, the steering angle θn is collected from the steering angle sensor 2 by a predetermined number or more at a sampling interval Ts. Here, the sampling interval Ts is, for example, 50 ms. Next step 5
2, the direction φn of the preceding vehicle from the preceding vehicle
And the inter-vehicle distance dn to the preceding vehicle are collected.

In step 53, a smooth value θn-tilde is calculated by the above equation (11) based on three adjacent steering angles θn at intervals of 150 ms, and an estimated steering angle θn-hat is calculated by the Taylor expansion shown in the above equation (12). Calculate. In step 54, a steering angle estimation value θn-hat ′ is calculated by Expression 6 based on the preceding vehicle direction φ from the preceding vehicle following travel control device 7.

In step 55, in order to eliminate the influence of the change in the preceding vehicle direction φ due to the interruption during the preceding vehicle following running control or the change of the following vehicle, it is confirmed whether or not the above equation 7 is satisfied. Steering angle estimation values θn-hat 'and θn
If the absolute value of the difference from -hat is equal to or greater than the predetermined value θo, it is determined that the preceding vehicle direction φ has significantly changed due to an interruption during the preceding vehicle following travel or a change in the following vehicle, and the steering angle obtained this time. The program returns to the program in FIG. 13 without using the estimated values θn-hat and θn-hat ′ in the process of detecting the unstable driving operation state.

If the absolute value of the difference between the estimated steering angle θn-hat 'and θn-hat is smaller than the predetermined value θo, the process proceeds to step 56,
Referring to the map data shown in FIG.
A correction coefficient Kn corresponding to n is determined. In step 57, the steering angle estimation value θn-hat calculated based on the past steering angle detection value by Taylor expansion and the steering angle estimation value θn− calculated based on the preceding vehicle direction φ from the preceding vehicle following control device 7. hat ′ is weighted by the correction coefficient Kn, and the final estimated steering angle θn-hat ″ is calculated by the above equation (8).

In step 58, the steering error e is calculated by the following equation.
Calculate n '.

[Equation 14] In step 59, as shown in Table 2, the steering error en 'resulting from the calculation is classified into nine categories b1 to b9 based on the α value at no load, and the total frequency of the steering error en' included in each category bi is calculated. Is determined. Then, in step 60, the steering angle entropy Hp value is calculated by the above equation (9).

In step 43 of FIG. 13 after the calculation of the Hp value,
It is determined whether or not the calculated Hp value exceeds the abnormal value Hpk. If the calculated Hp value exceeds the abnormal value Hpk, the process proceeds to step 44, and an operation corresponding to an unstable state is executed. Basically, the speaker 5 warns to call attention to driving. An alarm may be issued by a buzzer or a horn. Alternatively, an illuminating light in the vehicle, an indicator light provided on the instrument panel, or the like may be turned on to alert the driver to driving by light. In addition, the driver's seat may be vibrated or a stimulating odor may be emitted to draw attention.

When an unstable driving state is detected on the operation touch panel of the display 4, the number of touch switches that can be operated is reduced, and the operation contents and types are restricted to make the driving state unstable. May be removed. These operations include an operation of an air conditioner, an operation of a navigation device, an operation of a vehicle-mounted telephone, an operation of audio, an operation of a visual device, and the like.

If the following condition is detected by the following control device 7 while the vehicle is following the preceding vehicle at a constant inter-vehicle distance, the inter-vehicle distance is considered in consideration of the delay of the braking operation in the unstable state. The distance may be longer than usual.

Driving while receiving information providing services such as traffic information, telephone number guidance, telephone number connection, destination setting, weather forecast guidance, and news guidance between the navigation device and the information provision service center through a telephone line. When the unstable state is detected, the service content by broadcasting or display may be simplified, or the provision of the service may be temporarily stopped to eliminate the cause of the unstable state.

In the above-described embodiment, the estimated steering angle θn-hat calculated by the Taylor expansion based on the past detected steering angle θn and the direction φn of the preceding vehicle from the preceding vehicle following travel control device. Is weighted according to the inter-vehicle distance dn to the preceding vehicle, and the final steering angle estimated value θn-hat ”is determined by weighted averaging. An example in which the unstable state of the driving operation is detected based on the steepness of the distribution of the steering error between the typical steering angle estimated value θn-hat ”and the detected steering angle θn has been described. On the other hand, the direction φn of the preceding vehicle from the preceding vehicle
Using only the estimated steering angle θn-hat 'calculated based on the steering angle distribution based on the steepness of the distribution of the steering error between the estimated steering angle θn-hat' and the detected steering angle θn. The state may be detected. In this case, since the correction of the estimated steering angle based on the inter-vehicle distance dn to the preceding vehicle is not performed, the final estimated steering angle θn-ha of the embodiment is not corrected.
Although the detection accuracy of the unstable driving operation state is lower than the case of using "t", it is practically sufficient, and the detection processing of the unstable driving operation state is simplified as compared with the method of the embodiment. An unstable state can be detected in a short time.

[Brief description of the drawings]

FIG. 1 is a diagram for explaining a method of calculating a steering angle estimated value θn-hat by Taylor expansion based on a past detected steering angle value to obtain a steering error en.

FIG. 2 is a diagram illustrating a steering error en during traveling on a curved road when a steering angle estimation value θn-hat is calculated by Taylor expansion based on past steering angle detection values.

FIG. 3 is a diagram in which a direction φ and a distance d of a preceding vehicle on a curved road are detected by a radar sensor of the preceding vehicle following travel control device.

FIG. 4 is a diagram illustrating a method of calculating a steering angle estimated value θn-hat ′ based on a direction φ of a preceding vehicle from a preceding vehicle following travel control device.

FIG. 5 is a diagram illustrating a case where a direction φ of a preceding vehicle changes significantly during follow-up traveling control.

FIG. 6 is a diagram showing a correction coefficient Kn for an inter-vehicle distance dn to a preceding vehicle.

FIG. 7 is a diagram for explaining a steering tendency according to an inter-vehicle distance dn to a preceding vehicle.

FIG. 8 is a diagram showing a configuration of an embodiment.

FIG. 9 is a flowchart showing an IGN-on control program.

FIG. 10 is a flowchart showing a no-load α value calculation routine.

FIG. 11 is a diagram showing a distribution example of the frequency of the steering error en.

FIG. 12 is a flowchart illustrating an α value calculation routine.

FIG. 13 is a flowchart showing a timer interrupt routine.

FIG. 14 is a flowchart showing an HP value calculation routine.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 arithmetic and control unit 2 steering angle sensor 3 vehicle speed sensor 4 display 5 speaker 6 AVCN equipment 7 cruise control device for preceding vehicle 8 radar sensor

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) B60R 21/00 624 B60R 21/00 624G B62D 6/00 B62D 6/00 F02D 29/02 301 F02D 29/02 301D // B62D 101: 00 B62D 101: 00 113: 00 113: 00 F term (reference) 3D032 CC04 DA03 DA23 DD02 EB04 3D037 FA01 FA10 FA16 FA23 FA26 FB09 FB10 FB11 FB12 3D044 AA25 AA45 AC00 AC26 AC55 AC56 AC59 AD00 AE19 AE21 3A AA01 BA14 BA23 CB10 DB00 DB05 DB16 FA02 FA03 FA05 FA07 FA11 5H180 AA01 CC03 CC14 CC01 LL01 LL04 LL07 LL09

Claims (4)

[Claims] 1. A steering angle detecting means for repeatedly detecting a steering angle θ, a steering angle detection value θn (n =...
1, n) based on the steering angle estimating means A for calculating the steering angle estimated value θn-hat when it is assumed that the driver concentrates on the driving operation, and an obstacle existing in front of the vehicle. Obstacle detecting means for repeatedly detecting the direction φn and the distance dn of the vehicle, and specifying the preceding vehicle on the own vehicle traveling lane based on the direction detection value φn of the obstacle and the distance detection value dn, while maintaining a constant inter-vehicle distance. A preceding vehicle following control means for controlling the vehicle so as to follow the preceding vehicle; and a steering angle estimation value θn when it is assumed that the driver concentrates on driving operation based on the detected direction value φn of the preceding vehicle. -hat '
And a steering angle estimation value θn-h in consideration of an inter-vehicle distance dn to a preceding vehicle.
Final steering angle estimate θn-hat ”from at and θn-hat '
A steering angle estimation value determining means for determining the steering angle; a steering error calculating means for calculating an error between the final steering angle estimated value θn-hat ”and the detected steering angle θn; and a steering error distribution based on the steepness of the steering error distribution. A driving operation monitoring device for a vehicle, comprising: an unstable state detection unit that detects an unstable state of the driving operation. 2. The driving operation monitoring device for a vehicle according to claim 1, wherein the steering angle estimation value determining means includes an inter-vehicle distance d to a preceding vehicle.
The shorter the n, the greater the weight for the estimated steering angle θn-hat ', and the weighted averaging of the estimated steering angle θn-hat and θn-hat' to determine the final estimated steering angle θn-hat ” A driving operation monitoring device for a vehicle, comprising: 3. The vehicle driving operation monitoring device according to claim 1, wherein the absolute value of the difference between the estimated steering angle θn-hat and θn-hat ′ is equal to or greater than a predetermined value θo. , Their estimated steering angle θn-hat
And θn-hat 'are not used for detecting an unstable operation state of the driving operation. 4. An obstacle detecting means for repeatedly detecting a direction and a distance of an obstacle present ahead of the vehicle from the own vehicle, and an obstacle detecting means for detecting a direction and a distance of the obstacle on the own vehicle traveling lane based on the detected direction and the detected distance of the obstacle. A preceding vehicle following control means that identifies the preceding vehicle and controls the vehicle to follow the preceding vehicle while maintaining a constant inter-vehicle distance, and the driver concentrates on the driving operation based on the detected value of the direction of the preceding vehicle. Steering angle estimating means for calculating an estimated steering angle when it is assumed that the steering angle has been calculated; steering angle detecting means for repeatedly detecting the steering angle; and steering error calculation for calculating an error between the estimated steering angle and the detected steering angle. A driving operation monitoring device for a vehicle, comprising: means; and an unstable state detection means for detecting an unstable state of the driving operation based on the steepness of the steering error distribution.