JP3323319B2 - Vehicle travel control device - Google Patents

Abstract

PURPOSE:To prevent the quick change of the control yaw rate value by judging the failure of a yaw rate sensor when such state is continued for the prescribed period or longer that the detected value of the steering wheel angle becomes a prescribed value or above and the detected value of the yaw rate becomes smaller than a prescribed value. CONSTITUTION:The steering device of a vehicle is constituted of a mechanism 14 steering front wheels 12, a mechanism 20 connected to it by a transmission shaft 16 and steering rear wheels 18, a mechanism 22 changing the steering ratio which is the ratio of the rear wheel steering angle against the front wheel steering angle, and a control unit 24 controlling the steering ratio changing mechanism 22. The control unit 24 controls the steering ratio changing mechanism 22 based on the detected signals from a steering angle sensor 25, a steering ratio sensor 26, a vehicle speed sensor 27, and a yaw rate sensor 28. The control unit 24 judges the failure of the yaw rate sensor 28 when such state is continued for a prescribed period or longer that the detected value of the steering angle becomes a prescribed value or above and the detected value of the yaw rate becomes smaller than a prescribed value.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for judging a failure of a yaw rate sensor and a traveling control apparatus for a vehicle to which the method for judging a failure of a yaw rate sensor is applied.

[0002]

2. Description of the Related Art Conventionally, a device for feedback-controlling a running state of a vehicle according to a vehicle speed, a steering angle of a steering wheel, a yaw rate, etc., for example, is configured to variably set a steering ratio of a rear wheel to a steering angle of a front wheel. BACKGROUND ART Vehicle steering devices and the like are known.

[0003] The use of a yaw rate sensor for such vehicle running control is, for example, in the case of a vehicle steering system, the rear wheels are initially turned out of phase with the front wheels in accordance with the steering of the steering wheel under predetermined running conditions. When the steering wheel is turned around the vertical axis passing through the center of gravity of the vehicle (yaw), the rear wheels are steered to the same phase as the front wheels, so that the control of the steering wheel operation can be performed without discomfort. This is because it is necessary to detect the yaw rate (yaw angular velocity), and by using the yaw rate sensor, it is possible to improve the turning performance and the running stability.

In the case where a yaw rate sensor is used for the above-mentioned purpose, the difference between the rotational speeds of the left and right driven wheels and the steering wheel is determined in order to determine whether or not the yaw rate detected by the yaw rate sensor is reliable. An estimated yaw rate is calculated based on the steering angle and the like, and the estimated yaw rate and
A steering device for a vehicle including failure determination means for determining a failure of the yaw rate sensor when the difference between the estimated yaw rate and the actual yaw rate is equal to or more than a predetermined value by comparing the actual yaw rate detected by the yaw rate sensor is also proposed. (See Japanese Patent Application Laid-Open No. 2-249765).

[0005] In this type of vehicle steering system, failure determination means for determining a failure of the yaw rate sensor is provided. When a failure determination is made by the failure determination means, another traveling state detection means is immediately provided. For example, the steering control is switched to a vehicle speed sensor or a steering angle sensor.

[0006] The above-described failure determination is performed, for example, in the following procedure. That is, when it is detected that the difference between the estimated yaw rate estimated from the steering wheel angle and the actual yaw rate is equal to or greater than a predetermined value, or when the actual yaw rate is fixed to a constant value without changing, At this point, a timer is set, and the yaw rate value used for control is fixed to the normal actual yaw rate value detected in the previous control cycle until the predetermined time set by the timer elapses. If the difference between the estimated yaw rate and the actual yaw rate recovers to less than the predetermined value before the predetermined time set by the timer elapses, normal control using the actual yaw rate is performed without performing a failure determination. Let it return. Also, if the difference between the estimated yaw rate and the actual yaw rate does not return to less than the predetermined value even after the predetermined time has elapsed while the fixed value is used for control, or if the fixed state of the actual yaw rate value is not resolved The failure determination of the yaw rate sensor is performed only when the predetermined time has elapsed,
Immediately, the steering control is switched to another driving state detection sensor, for example, a vehicle speed sensor or a steering angle sensor.

As described above, by using the timer and prohibiting the failure determination until the predetermined time set by the timer elapses, the low μ road can be maintained despite the normal operation of the yaw rate sensor. If the difference between the estimated yaw rate and the actual yaw rate becomes a predetermined value or more in the short term due to the slip of the wheels during running or the occurrence of noise, etc., or if the output of the yaw rate sensor is fixed in the short term, This prevents the failure determination of the yaw rate sensor from being performed.

[0008]

However, such a conventional vehicle travel control device that determines the failure of the yaw rate sensor has the following problems.

FIG. 12 is a waveform diagram for explaining the failure judgment of the yaw rate sensor. In the figure, the actual yaw rate ψ ′ (dash represents differentiation), which is the output of the yaw rate sensor, is indicated by a broken line, the estimated yaw rate ψ ′ _B corresponding to the steering angle θ _H is indicated by a dashed line, and the actual yaw rate ψ The yaw rate ψ ′ _A (hereinafter referred to as “control yaw rate”) used for actual control along the line ′ is shown by a solid line. Then, despite the normal operation of the yaw rate sensor, the actual yaw rate ψ ′ is delayed from the estimated yaw rate ψ ′ _B estimated from the steering wheel angle θ _{H due} to the slip of the wheels when traveling on a low μ road. And there is a considerable difference between the two.

At time t ₁ or t ₄ , | ψ ′
Chromatography [psi _'B | When became ≧ d, it is determined that the control unit is abnormal in the yaw rate sensor occurs, the control yaw rate [psi shown by the solid line in FIG. 9' secure the _A to the value of the actual yaw rate [psi 'previous At the same time, the count-up of the timer counter with the set time as Ty is started.
Then, based on the time t ₁ or t _4, the setting time than the time t3 or t6 reaches Ty previous time t ₂
In or t _5, | ψ 'over ψ' _B | <because became d, 'is _A the actual yaw rate [psi' control yaw [psi and returns to the line of, it will vary along the actual yaw rate [psi 'again .

That is, as is apparent from FIG. 12, the value of the control yaw rate ψ ′ _A rapidly changes at the time t ₂ or t ₅ , and accordingly, the control yaw rate ψ ′ _A For example, since the steering angle of the rear wheels is rapidly changed, the behavior of the vehicle becomes discontinuous, and there is a problem that the occupant is discomforted.

The present invention has been made in view of such circumstances, and it is intended to prevent a sudden change in the value of the control yaw rate 、 ' _A , thereby enabling a smooth running control of a vehicle.
It is intended to provide a control device .

[0013]

SUMMARY OF THE INVENTION A traveling control device for a vehicle according to the present invention includes a steering angle sensor for detecting a steering angle of a steering wheel, a yaw rate sensor for detecting a yaw rate, and a steering angle and a yaw rate detected by these sensors. A steering angle detected by the steering angle sensor in a configuration including at least traveling control means controlled based on the steering angle and failure determination means for determining a failure of the yaw rate sensor;
Estimated yaw acceleration calculating means for calculating the estimated yaw acceleration from
Wherein the failure determination means outputs data regarding the steering wheel angle detected by the steering angle sensor to a first position.
And the yaw rate data detected by the yaw rate sensor is smaller than a second predetermined value for a first predetermined time, or the steering wheel detected by the steering angle sensor If the state in which the data related to the steering angle is equal to or smaller than the third predetermined value and the data related to the yaw rate detected by the yaw rate sensor is larger than the fourth predetermined value continues for a first predetermined time , it is determined that a failure has occurred. Configured to
Have been.

Until the time when the failure determination means determines a failure, the data on the yaw rate is used for controlling the traveling control means, and the failure determination means uses the data.
Until the second predetermined time elapses from the time when the
Is the estimated value calculated by the estimated yaw acceleration calculating means.
The yaw acceleration is used for controlling the traveling control means .

Another embodiment of the vehicle traveling control device according to the present invention.
According to the above, the yaw rate detected by the yaw rate sensor is
Means for calculating the actual yaw acceleration from the rate
From the steering angle detected by the steering angle sensor
Estimated yaw acceleration calculating means for calculating yaw acceleration
The failure determination means is controlled by the steering angle sensor.
The data relating to the detected steering angle is a first predetermined value.
Value and is detected by the yaw rate sensor.
Data about the yaw rate to be set is smaller than the second predetermined value.
If the lowered state continues for the first predetermined time,
Is related to the steering angle detected by the steering angle sensor.
Data is less than or equal to a third predetermined value, and
Data on yaw rate detected by the speed sensor
Is greater than a fourth predetermined value for a first predetermined time
If it continues, it is configured to determine that it has failed.
I have.

The failure determination means determines that the failure has occurred.
Up to the point where the
The failure determination means is used for controlling the travel control means.
In the actual yaw acceleration calculation.
Actual yaw acceleration calculated by the step and the estimated yaw acceleration
The difference from the estimated yaw acceleration calculated by the calculating means is the fifth.
If it is equal to or greater than the predetermined value of
Until the second predetermined time elapses from the time when the
Uses the estimated yaw acceleration to control the travel control means.
It is characterized by the following.

The traveling control means comprises, for example, rear wheel turning means.

[0018]

Driving control of the vehicle according to the action and effects of the present invention
In the device , when the data relating to the steering angle of the steering wheel is equal to or more than a predetermined value, and the state where the yaw rate detected by the yaw rate sensor or the yaw acceleration calculated from the yaw rate is smaller than the predetermined value continues for a predetermined time, Alternatively, if the data relating to the steering angle of the steering wheel is equal to or smaller than a predetermined value and the yaw rate detected by the yaw rate sensor or the yaw acceleration calculated from the yaw rate is larger than a predetermined value, the failure occurs for a predetermined time. Therefore, it is determined that the yaw rate sensor is determined to be failed due to slippage of the wheels during low μ road running or noise or the like despite the normal operation of the yaw rate sensor. Can be prevented, and the failure judgment of the yaw rate sensor can be accurately performed. There is a result.

Further, in the vehicle traveling control apparatus according to the present invention, the failure determining means determines whether or not the failure has occurred.
, Since the data relating to the yaw rate is used for the control of the running control means, for example, when the traveling control means is a rear wheel steering means, during counting of the predetermined time, seen as a yaw rate sensor fails Even when the vehicle returns from the assumed state, no sudden change is made in the control of the traveling control means, and the vehicle behavior becomes discontinuous due to a sudden change in the rear wheel steering angle. Can be avoided, or the occupants are uncomfortable.

Further, according to the present invention, even if the output of the yaw rate sensor is fixed, the control yaw rate ψ ′ _A is not used between time points t1 and t3 and between time points t4 and t6 in FIG. Is not fixed, and the value of the fixed actual yaw rate ψ ′ is directly used as the control yaw rate ψ ′ _A
And if the fixation of the yaw rate sensor does not recover, a failure determination is made at times t3 and t6. Therefore, even if the output of the yaw rate sensor is fixed, danger may be caused. Not something.

Further, according to the present invention, the failure judgment
If this happens, the estimated yaw
Since the acceleration is used to control the travel control means,
Qualitative properties can be improved.

[0022]

Embodiments of the present invention will be described below with reference to the accompanying drawings.

FIG. 1 is a diagram showing a schematic configuration when the present invention is applied to a vehicle steering system.

In FIG. 1, a vehicle steering system 10 is mechanically connected to a front wheel steering mechanism 14 for steering a front wheel 12 via a transmission shaft 16.
In conjunction with the front wheel steering by the front wheel steering mechanism 14, the rear wheels 1
A rear wheel steering mechanism 20 that steers 8 to a predetermined target rear wheel steering angle TGθ _R (which will be described later) in accordance with the front wheel steering angle θ _F input from the front wheel steering mechanism 14; provided wheel steering mechanism 20, a steering-angle-ratio adjusting mechanism 22 for setting and changing the steering angle ratio theta _S, expressed as a ratio of rear wheel steering angle theta _R for the front wheel steering angle theta _F, this steering angle ratio Variable mechanism 2
A control unit 24 for controlling the steering angle θ _H from a steering angle sensor 25 (provided on the steering shaft), and a control unit 24 for controlling the steering ratio sensor 26. Signals representing the steering ratio θ _S , the vehicle speed V from the vehicle speed sensor 27, and the yaw rate ψ ′ from the yaw rate sensor 28 are input.

The yaw rate sensor 28 detects the yaw rate ψ 'when the vehicle is turning using the Coriolis force generated by the vibrating tuning fork.

Further, the control unit 24 includes:
Each signal from the rough road sensor 23 and the brake switch 29 is also input. Since the configuration of the rear wheel steering mechanism 20 is known from Japanese Patent Application Laid-Open No. 4-108079, a detailed description thereof will be omitted.

FIG. 2 is a block diagram of the vehicle steering system 10 according to the present embodiment.

The control unit 24 includes a steering angle speed calculating means 31 for calculating the steering wheel angular velocity theta _'H, a yaw acceleration calculating means 32 for calculating the actual yaw acceleration [psi ", determines failure determination means the failure of the yaw rate sensor 28 34, a timer 33, an estimated yaw acceleration calculating means 35 for calculating an estimated yaw acceleration ψ ″ _B from the steering angular velocity θ ′ _H ,
At the time of the failure determination by the failure determination means 34,
4, a yaw acceleration correction unit 36 for correcting the actual yaw acceleration ψ ″ to a correction reference value based on the fail determination signal output from the control unit 4, a control mode selection unit 37 for selecting a control mode based on the fail determination signal, Of the rear wheels 18, 18 based on the signals and signals representing the front wheel steering angle θ _F , the yaw rate ψ ′, the vehicle speed V, the steering angular velocity θ ′ _H , and the actual yaw acceleration ψ ″ obtained from the steering angle θ _H. Turning ratio calculating means 38 for calculating the turning ratio and the turning speed
A steering ratio control unit 40 for outputting a drive signal to a drive circuit 39 of a steering ratio variable servo motor based on a signal from the steering ratio calculation unit 38; a motor failure determination unit 41; A determination timer 42 and a motor responsiveness changing unit 43 are provided.

The steering angular velocity calculating means 31 receives the steering angle signal from the steering angle sensor 25, calculates the steering angular velocity based on the steering angle signal, and calculates the estimated yaw acceleration calculating means 35.
It is configured to output a steering angular velocity signal to the failure determination means 34. The yaw acceleration calculating means 32 includes:
Based on the yaw rate signal from the yaw rate sensor 28, shown in FIG. 4, "a map showing a relationship is _B, the estimated yaw acceleration [psi" and steering angular steering speed theta _'H estimated yaw acceleration [psi computes _B, the estimated The yaw acceleration signal is output to the fail judging means 34 and the yaw acceleration correcting means 36.

The yaw acceleration correcting means 36 receives signals from the fail judging means 34 and the estimated yaw acceleration calculating means 35, and is calculated by the estimated yaw acceleration calculating means 35 based on the failure judging signal from the fail judging means 34. With the estimated yaw acceleration ψ ″ _B as a correction reference value, a control signal is output to the control mode selection means 37 so as to perform control based on the correction reference value, and the correction reference value is output to the fail determination means 34. Have been.

The failure determining means 34 is provided with the steering angle sensor 2
5. Receives signals from the vehicle speed sensor 27, the yaw rate sensor 28, the steering angular velocity calculating means 31, the yaw acceleration calculating means 32, the estimated yaw acceleration calculating means 35, and the yaw acceleration correcting means 36, and determines a yaw rate failure based on these signals. Is started and the timer 33 is started.
If the yaw rate failure determination condition is not resolved even after the set time elapses, the yaw rate sensor 28 determines that the failure has occurred, and sends the determination signal to the control mode selection means 37.
, And the failure determination signal is also output to the yaw acceleration correction means 36.

[0032] That is, the fail determining means 34, the vehicle speed V is the predetermined speed detected by the vehicle speed sensor 27 (e.g., 40 km / h) or more, and the steering angular velocity calculating means 31 by the calculated steering angular steering angular theta _'H is When the yaw acceleration ψ ″ calculated by the yaw acceleration calculating means 32 is equal to or greater than a predetermined value (eg, 200 deg / sec) and equal to or less than a predetermined reference value (eg, 1.0 deg / sec), it is determined whether or not a failure has occurred. Start monitoring and start the timer 33,
If the above condition is not resolved even after the set time of the timer 33 has elapsed, the yaw rate sensor 28 is configured to determine that it has failed.

The fail determining means 34 determines that the vehicle speed V detected by the vehicle speed sensor 27 is equal to or higher than a predetermined low vehicle speed (for example, 10 km / h) and that the steering angle θ _H detected by the steering angle sensor 25 is a predetermined value. When the yaw rate ψ ′ detected by the yaw rate sensor 28 is smaller than a predetermined value (eg, 5 deg / sec), the monitoring of the failure is started and the timer 3 is started.
If the above conditions are not resolved even after the set time of the timer 33 has elapsed after the start of the timer 3, the yaw rate sensor 28 is determined to have failed.

The failure determining means 34 determines that the vehicle speed V detected by the vehicle speed sensor 27 is a predetermined speed (for example, 4
0 km / h) or more and the actual yaw acceleration ψ ″ inputted from the yaw acceleration calculating means 32 is the estimated yaw acceleration calculating means 35
When the estimated yaw acceleration ψ ″ _B , which is input from the control unit, is out of the allowable range, the yaw rate sensor 28 is determined to have failed.

Further, even after the output of the fail signal, the fail judging means 34 calculates the actual yaw acceleration ψ ″ calculated by the yaw acceleration calculating means 32 and the yaw acceleration correcting means 3.
6 is configured to repeatedly compare and determine the correction reference value input from 6 with a plurality of times, and to output a fail determination signal to the control mode selecting means 37 based on the plurality of times of fail determination at this time. ing.

The control mode selecting means 37 selects a control mode A1, a control mode A2, a control mode A3 and a control mode B according to a signal from the fail judging means 34.
The control mode signal is output to the turning ratio calculating means 38.

Here, the control mode A1 is a mode in which control is performed based on the actual yaw acceleration ψ ″ calculated by the yaw acceleration calculation means 32, and the control mode A2 is a control mode calculated by the estimated yaw acceleration calculation means 35. Control mode based on yaw acceleration ψ ″ _B , control mode A
3 is a mode in which control is performed using the previously detected yaw rate. In the control mode B, the yaw rate sensor 28
This is a control mode of control based on signals from other sensors 25 and 26 other than the two-wheel steering control for steering only the front wheels.

The steering ratio calculating means 38 receives a steering angle signal from the steering wheel steering angle sensor 25, a vehicle speed signal from the vehicle speed sensor 27, a yaw rate signal from the yaw rate sensor 28, and a control mode signal from the control mode selecting means 37. ,
On the basis of these input signals, the steering ratio and the steering speed of the rear wheels 18, 18 with respect to the front wheels 12, 12 are calculated in accordance with predetermined steering ratio characteristics, and are output to the steering ratio control means 40. Have been.

The turning ratio calculating means 38 is configured to output a rear wheel steering stop signal to the turning ratio control means 40 when a two-wheel steering control mode signal is input from the control mode selecting means 37. I have.

The turning ratio control means 40 includes a turning ratio calculating means 3
A target steering ratio TGshita _S calculated by 8, and the detected steering angle theta _H detected by the steering angle sensor 25, a signal representative of each detected detected steering angle ratio theta _S and with steering ratio sensor 26 The steering angle θ _R of the rear wheels 18 is obtained based on the target steering ratio TGθ _S and the detected steering angle θ _H, and the steering angle is feedback-controlled based on the detected steering ratio, and the steering angle is determined. Is output to the motor drive circuit 39, and a servo motor (not shown) provided in the rear wheel steering mechanism 20 is operated via the motor drive circuit 39.

The motor responsiveness changing means 43 receives the output of the vehicle speed sensor 27 and makes the responsiveness of the servomotor lower at low speeds than at high speeds.

The motor failure determining means 41 compares the target turning ratio calculated by the turning ratio calculating means 38 with the turning ratio actually measured by the turning ratio sensor 26, and calculates the turning ratio of the servo motor. When the driving of the variable mechanism 22 is started, the timer 42 is started. When the difference between the target turning ratio and the actually measured turning ratio does not become smaller than a predetermined value when a predetermined time (threshold time) has elapsed. The motor failure determination signal is output to the control mode selection means 37, and the motor failure determination threshold time increases as the response speed of the servomotor decreases at low speeds compared with the response speed at high speeds. Changed to be longer than time.

The control mode selection means 37 is configured to select a control mode B (two-wheel steering) when receiving a motor failure determination signal from the motor failure determination means 41.

The control unit 24 calculates a vehicle speed V obtained by averaging the rotational speeds V ₁ and V ₂ of the left and right driven wheels.
Yaw rate ψ ', front wheel steering angle θ _F , and front wheel steering angle θ _F
Of the front wheel steering angle change rate θ ′ _F2 obtained by differentiating the front wheel steering angle, and adding or subtracting a signal operation value obtained from each detection signal to obtain a target turning ratio TGθ _S (rear wheel turning control target value) for the turning ratio variable mechanism 22. ) was determined, further the target steering angle ratio TGshita _S is, when it exceeds a predetermined allowable range set in accordance with the vehicle speed, so as to correct the target turning ratio TGshita _S to a value within the permissible range ing. Then, the corrected target turning ratio TG
Using θ _S1 , the target rear wheel steering angle TGθ _R is calculated by the following equation: TGθ _R = θ _F · TGθ _S1 .

[0045] The target steering ratio TGshita _S, the following formula _{TGθ S = -G 1 · f 1} (V) · θ S · ST + G 2 · K 2 (θ F2) · J 2 (| θ 'F2 |) • f ₂ (V) • θ _S • _YAW −G ₃ • K ₃ (θ _F2 ) • f ₃ (V) • θ _S • _STD + G ₄ • f ₄ (V)

In the above equation, the first term on the right side is a steering angle correction term,
The second term is a yaw rate correction term, the third term is a steering angle change rate correction term, and the fourth term is a vehicle speed sensitive term that is a base when performing rear wheel turning control according to the vehicle speed. By thus setting the target steering ratio TGshita _S, a vehicle speed sensitive rear wheel steering control as a basis, when turning the front wheels from the straight running condition, and the rear wheel on the turning initial front orientation Control to increase the turning performance by turning to the opposite phase side where the direction is opposite, and then to steer the rear wheel to the same phase side where the direction of the front wheel becomes the same as the front wheel due to the yaw rate generation (phase control) (Inversion control).

In the above equation, G ₁ , G ₂ , G ₃ , G ₄ are constants, and other variables are the vehicle speed V, as shown in FIG.
Based on the yaw rate [psi 'and front wheel steering angle theta _F, it is adapted to be calculated as follows.

First, the variables f ₁ (V), f
₂ (V), f ₃ (V), and f ₄ (V) are vehicle speed-sensitive gains, and are obtained from the vehicle speed V based on maps m10, m5, m13, and m.
1, each is calculated. Maps m10 and m13 of the above maps are variables f ₁ (V),
The characteristic is that f ₃ (V) is 0 in a low vehicle speed region and a high vehicle speed region, and a positive constant value in a middle vehicle speed region. The map m5 of the above maps is a variable f
₂ (V) is a characteristic that is 0 in a low vehicle speed region and a positive constant value in a middle vehicle speed region and a high vehicle speed region. Further, the remaining map m1 changes the variable f ₄ (V) from a negative value to a positive value in a low vehicle speed region, from a negative value to a positive value as the vehicle speed increases in a medium vehicle speed region, and to a positive positive value in a high vehicle speed region. It is a characteristic to be a value.

Next, the variable θ _S · _ST of the first term on the right side is a steering angle correction value, and the front wheel steering angle θ _F is added with an offset by using a map m8 to obtain θ _{F1, which} is then obtained by a map m11. Hysteresis is added to θ _F1 to obtain θ _F2 , and the absolute value thereof is calculated from | θ _F2 | using a map m9. Adding an offset in map m8 is
This is to prevent unnecessary control from being performed by providing a dead zone in the small steering angle area.
The reason why the hysteresis is added at 1 is to prevent hunting from occurring in the control. The map m9 indicates that the variable θ _S · _ST is 0 in a small steering angle area, a value proportional to the steering angle in a middle steering angle area, a positive constant value in a large steering angle area, and a larger steering angle area. Has a characteristic of being set to 0 when an abnormality has occurred.

Next, the variable theta _S · _YAW of the second term is a yaw rate correction value, after the ₁ '[psi by adding an offset by map m2' yaw rate [psi, map m3
From ψ ′ ₂ with hysteresis added to ψ ′ ₁ ,
The calculation is performed using the map m4. The reason for adding the offset and the hysteresis is the same as in the case of the variable θ _S · _ST . The map m4 is a variable θ
_S · _YAW has a characteristic of being a value proportional to ψ ′ ₂ in the small yaw rate region, a positive constant value in the middle yaw rate region, and 0 in the large yaw rate region when an abnormality has occurred.

The variable K ₂ (θ _F2 ) of the second term on the right side is
Steering angle sensitive gain, θ _F2 obtained in map m11
From the map m6. The map m6 has a characteristic that the variable K ₂ (θ _F2 ) is a value that is substantially proportional to θ _F2 in the small front wheel steering angle region, and a value that decreases as the front wheel steering angle increases.

Further, the variable J ₂ (| θ ′) of the second term on the right side
_F2 |) is a steering angle change rate sensitive gain, and is a map m1
The absolute value was obtained by differentiating θ _F2 obtained in Step 1 | θ ' _F2 |
From the map m7. The map m7 is obtained by converting the variable J ₂ (| θ ′ _F2 |) into | θ ′ _F2 |
Is small in the region where the front wheel steering angle change rate is small, that is, the value is large in the middle front wheel steering angle change rate region, and the value is even smaller in the large front wheel steering angle change rate region than the small front wheel steering angle change rate region. Has become.

In the control unit 24,
Two types of maps are stored for a low μ road and a high μ road. When a map for a low μ road is used, the second map on the right side is used.
The variable J ₂ (| θ ′ _F2 |) of the term is omitted, whereby
It improves driving stability.

Next, the variable θ _S · _STD of the third term on the right side is a steering angle change rate correction value, and is calculated from the value θ ′ _F2 obtained by differentiating θ _F2 obtained in the map m11 by the map m12. It has become. The map m12 expresses the variable θ _S · _STD by:
In the small front wheel steering angle change rate region, the value is proportional to θ ' _F2 , in the middle front wheel steering angle change rate region, a constant positive value, and in the large front wheel steering angle change rate region, it is set to 0 when an abnormality occurs. .

The variable K ₃ (θ _F2 ) of the third term on the right side is
Steering angle sensitive gain, θ _F2 obtained in map m11
From the map m14. The map m14 has a characteristic that the variable K ₃ (θ _F2 ) is set to a value that is substantially proportional to θ _F2 in the small front wheel steering angle region, and a value that decreases as the front wheel steering angle increases.

The target turning ratio TGθ _S is determined by adding or subtracting a signal operation value obtained by multiplying each of the terms on the right side of the above equation by the above constants and variables. taking, the target steering angle ratio TGshita _S becomes an abnormal value, the map m15, the target steering ratio TGshita _S is,
When the target turning ratio TGθS exceeds the allowable range set in accordance with the vehicle speed V (the portion indicated by oblique lines in the map m15), the target turning ratio TGθ _S is set to the upper limit or the lower limit within the allowable range (the curve indicated by the broken line in the map m15). ). The solid line curve in the map m15 is the variable f ₄ (v) shown in the map m1.

FIG. 5 is a flowchart of control mode setting control in the vehicle steering control of the present embodiment. FIG. 6 is a flowchart showing an example of the content of the fail determination processing of the yaw rate sensor included in the flowchart of FIG. In the figure, S indicates each step.

The yaw rate sensor 28 may malfunction if a relatively large G acts due to its structure. Therefore, in the present embodiment, the yaw rate sensor 2
8 when the vehicle is traveling on a rough road where a relatively large vertical G acts on the yaw rate sensor 28 and when the vehicle speed when the relatively large front and rear G acts on the yaw rate sensor 28 is equal to or more than a predetermined value (for example, 60 km / h) and when the wheels are braked (the brake pedal is depressed). Brake switch 29 is O
N), the failure determination process of the yaw rate sensor shown in FIG. 6 is prohibited.

The control mode setting control of this embodiment is started by turning on an ignition switch. First, a vehicle speed V and an actual yaw rate ψ 'are obtained from a steering angle sensor 25, a steering ratio sensor 26, a vehicle speed sensor 27 and a yaw rate sensor 28. , The reading of the steering angle θ _{H and} the reading from the rough road sensor 23 and the brake switch 29 are executed (S
1).

Next, it is determined whether the vehicle is traveling on a rough road, whether the vehicle speed is equal to or higher than a predetermined value (for example, 60 km / h) and the brake pedal is depressed (S2, S3). (S2: YES) and a vehicle speed of a predetermined value (for example, 60 km
/ h) and at the time of wheel braking (S3: YES), control in the control mode B is executed (S13), and the process returns to S1.

When the vehicle is not running on a rough road (S2: NO) and when the vehicle is not braking (S3: NO), a failure determination process of the yaw rate sensor 28 shown in FIG. 6 is executed (S4).

Here, the fail determination process of the yaw rate sensor 28 will be described with reference to FIG. 6. A fail flag Ff, a vehicle speed flag Fv set when the vehicle speed V is lower than a predetermined vehicle speed, and a steering angular speed θ ′ _H Is smaller than a predetermined value, the steering angle flag Fθ is reset (S31), and the vehicle speed V detected by the vehicle speed sensor 27 is then reduced to a predetermined low vehicle speed V ₀ (for example, 10 k).
m / h) or more whether it is determined (S32), when the vehicle speed V is lower than a predetermined low vehicle speed V ₀ (S32: NO), since it can not determine the process, as well as set the vehicle speed flag Fv (S37), fail The determination flag Ehf and the timer 33 are reset (S41, S42), and the process returns.

When the vehicle speed V is equal to or higher than the predetermined low vehicle speed V ₀ (S3
2: YES), the steering angle θ _H becomes a predetermined value θ ₀ (for example,
It is determined whether or not the yaw rate ψ ′ detected by the yaw rate sensor 28 is equal to or greater than a predetermined value ψ ′ ₀ (for example, 5 deg / sec) (S33).
34).

As a result of these determinations, the yaw rate ψ ′ is smaller than the predetermined value ψ ′ ₀ even though the vehicle speed V is equal to or higher than the predetermined low vehicle speed V ₀ and the steering angle θ _H is equal to or higher than the predetermined value θ _0. In this case (S33: YES, S34: NO), the yaw rate is smaller than the predetermined value ψ ′ ₀ even though the steering wheel is turned, and in this case, the yaw rate sensor 28 is fixed near the center. Since there is a possibility that the failure determination flag Ehf is set (S43),
The timer 33 for setting the set time to T ₀ is set, and it is determined whether or not the time T ₀ has elapsed (S44).

Until the time T ₀ elapses (S4
4: NO), the timer 33 is counted up (S4).
5), when the set time T ₀ has elapsed (S44: YE
S), the fail flag Ef is set (S46), that is, the process is determined to have failed and returns.

On the other hand, when the vehicle speed V is equal to or higher than the predetermined low vehicle speed V ₀ and the steering angle θ _H is smaller than the predetermined value θ ₀ (S33: N
O), or when the yaw rate [psi 'is a predetermined value [psi' of ₀ or more (S34: YES), operation of the steering speed theta 'operations and yaw acceleration of _H [psi "is performed (S35), the vehicle speed V is the predetermined speed V
₁ (for example, 40 km / h) or not (S3
6). As a result of this determination, when the vehicle speed V is the predetermined speed V ₁ or (S36: YES), the steering angular velocity theta 'absolute value of _H is a predetermined value theta' is determined whether _one or more (S38).

[0067] The results of this determination, the steering angular speed θ when 'the absolute value is a predetermined value θ of _{H' 1} or more (S38: YES), whether or not the yaw acceleration [psi "the absolute value of the predetermined reference value [psi" ₁ or more It is determined (S40).

[0068] Results of this determination, although the vehicle speed V is steering angular velocity theta at a predetermined speed V ₁ or 'absolute value of _H is a predetermined value theta' ₁ or more, the absolute value of the yaw acceleration [psi "predetermined reference Value ψ ″
If it is smaller than ₁ (S40: NO), the yaw rate is small even though the steering wheel is turned at the predetermined steering angular speed or higher at the predetermined vehicle speed or higher, and the yaw rate sensor 28 is located at a position considerably deviated from the center. In this case, the process proceeds to S43, in which the fail determination flag Ehf is set and the timer 3
3 is set, and the processing of S44 to S46 described above is performed.

[0069] Further, as a result of the determination in S36, when the vehicle speed V is smaller than the predetermined speed V ₁ (S36: NO), since it can not fail judgment by the yaw acceleration, the vehicle speed flag F
v is set (S37), and the fail determination flag Ehf is set.
And reset the timer 33 (S41, S42),
To return.

[0070] Further, as a result of the determination in S38, if the steering angular theta 'absolute value of _H is a predetermined value theta' smaller than ₁ (S3
8: NO), since the failure determination based on the yaw acceleration cannot be performed, the steering angle flag Fθ is set (S39), the failure determination flag Ehf and the timer 33 are reset (S41, S42), and the routine returns.

Further, as a result of the judgment in S40, when the absolute value of the yaw acceleration ψ ″ is equal to or more than the predetermined reference value ψ ″ ₁ (S4
In the case of 0: YES), the failure determination processing is ended, the failure determination flag Ehf and the timer 33 are reset (S41, S42), and the process returns.

After the above yaw rate sensor fail determination processing is completed, it is determined whether the fail flag Ff is set as shown in FIG. 5 (S5). If the fail flag Ff is set (S5: YES),
Can be estimated that the yaw rate sensor 28 is fixed, in order to confirm again fail in another way, the estimated value of the yaw acceleration is proportional to the steering angular velocity theta _'H, i.e., an estimated yaw acceleration [psi _"B 4 is calculated from the steering angular velocity θ ′ _H based on the map shown in FIG. 4 (S6), and the estimated yaw acceleration ψ ″ _B is compared with the actual yaw acceleration ψ ″ calculated by the yaw acceleration calculating means 32 (FIG. 4). S7).

If the difference between the actual yaw acceleration ψ ″ and the estimated yaw acceleration ψ ″ _B is smaller than the reference value ψ ″ ₂ (S7: NO), the signal from the yaw rate sensor 28 is normal. Therefore, the counter n is reset (S1
4) The control of the control mode A1 based on the yaw rate ψ ′ and the yaw acceleration ψ ″ detected by the yaw rate sensor 28 is executed (S15), and the process returns to S1.

Estimated yaw acceleration ψ ″ _B and actual yaw acceleration ψ ″
If the difference between the two is equal to or greater than the reference value ψ ″ ₂ (S7: YES), the yaw rate sensor 28 fails, but since the yaw rate has not been detected, the actual yaw acceleration ψ ″ is corrected. The estimated yaw acceleration ψ ″ _B , which is the reference value, is used (S8). Then, the counter n is incremented (S9), and it is determined whether or not the counter n is equal to or more than a predetermined number N (S10). If n has not reached the predetermined number n (S10: nO), "as a correction reference value estimated yaw acceleration [psi" actual yaw acceleration [psi using a _B, the control mode A2 based on the estimated yaw acceleration [psi _"B The control is executed (S11), and the process returns to S1.

As a result of the determination in S10, when the counter n has reached the predetermined number N (S10: YES), it is determined that the failure has been determined, the counter n is reset (S12), and based on the other sensors 25 and 27. The control of the control mode B is executed (S13), and the process returns to S1.

On the other hand, if the fail flag Ff is not set (S5: NO), the vehicle speed flag F
It is determined whether or not v is set (S16). As a result of the determination, when the vehicle speed flag Fv is set (S16: YES), that is, when the vehicle speed V is smaller than the predetermined vehicle speed in the failure determination process of the yaw rate sensor shown in FIG. 6, the failure determination of the yaw rate sensor is performed. Cannot be performed. At this time, due to an abnormal yaw rate signal,
Since the control imposes on steering stability, the counter n is reset (S20), and for example, control is performed in the control mode A3 using the previously detected yaw rate (S2).
1).

If the vehicle speed flag Fv is not set (S16: NO), it is determined whether the steering angle flag Fθ is set (S17). As a result of that judgment,
When the steering angle flag Fθ is set (S17: YE
S), the failure determination process of the yaw rate sensor shown in FIG. 6, the steering angular velocity theta _'H is smaller than the predetermined value, since it can not fail judgment by the yaw acceleration, for performing failure determination of the yaw rate in accordance with another method, the fail flag The same routine control as when Ff is set is performed (S6 to S15).

Further, when the fail flag Ff, the vehicle speed flag Fv and the steering angle flag Fθ are not set (S5, S16, S17: NO), the output from the yaw rate sensor 28 as described in the processing of FIG. Is normal, the counter is cleared (S18), control of the control mode A1 based on the current actual yaw rate and yaw acceleration is executed (S19), and the process returns to S1.

As described above, in this embodiment, the steering angle sensor 2
If the steering angle θ _H detected at 5 is equal to or greater than the predetermined angle θ ₀ ,
And the yaw rate ψ 'detected by the yaw rate sensor 28
Is smaller than a predetermined value ψ ′ ₀ , the yaw rate sensor 28 does not immediately determine a failure, and determines that a failure has occurred when this failure state continues for a predetermined time T _0. It is possible to prevent discontinuity of control in the case where the fail state is resolved before the time T ₀ elapses.

[0080] Further, the failure determination of the yaw rate sensor 28, 'since performed using _H and the yaw acceleration [psi ", can detect the fail prematurely, also, on the determination, the steering angular velocity theta' steering angular theta and _H , because of the use of the estimated estimation yaw acceleration [psi _"B or vehicle speed calculated from the steering speed theta _'H condition, fail also be reliably detected.

Further, when the fail flag Ef is set to 1, the fail of the yaw rate sensor 28 is not immediately decided but is decided for the first time by a plurality of fail judgments.
When a failure determination is made, the steering speed of the rear wheels is controlled based on the correction reference value ψ ″ _B until the failure is determined, so that steering stability can be improved.

In S33 and S34 of FIG. 6, it is determined whether the steering angle θ _H is equal to or larger than a predetermined value θ ₀ (S33).
Next, the yaw rate ψ ′ detected by the yaw rate sensor 28
There predetermined value [psi 'determines whether ₀ or more (S34), regardless the steering angle theta _H is also the predetermined value theta ₀ or more, the yaw rate [psi'
Is smaller than the predetermined value ψ ′ ₀ (S33: YES,
S34: NO), but it sets the failure determination flag Ehf (S43), as shown in FIG. 7, steering wheel angle theta _H is determined whether the predetermined value theta ₃ or less in S33 ', then 'in the yaw rate [psi detected by the yaw rate sensor 28' S34 it is judged whether or not a predetermined value [psi _'3 or less, the steering angle theta _H
There spite of equal to or less than the predetermined value theta _3, when the yaw rate [psi 'is a predetermined value [psi' greater than ₃ (S33 ': YES, S
34 ': NO), control for setting the fail determination flag Ehf (S43) may be added.

As shown in FIG. 8, when the difference between the yaw rate ψ 'detected by the yaw rate sensor 28 and the reference yaw rate ψ' _M calculated by the following equation is equal to or larger than a predetermined value, a fail judgment is made in S43. The use flag Ehf may be set.

Ψ ′ _M = ｛1 / (9.8 × wheel base)｝ × V ² × tan (θ _H / gear ratio) Here, the gear ratio is the ratio of the wheel steering angle to the steering wheel angle θ _H. .

Further, in S38 of FIG. 6, the steering angular velocity θ '
_It is determined whether or not the absolute value of _H is equal to or greater than a predetermined value θ ′ ₁ , and then S4
0, yaw acceleration [psi "the absolute value of the predetermined reference value [psi" it is determined whether or not _one or more, regardless of the steering speed theta 'absolute value of _H is a predetermined value theta' to ₁ or more, yaw acceleration When the absolute value of ψ ″ is smaller than the predetermined reference value ψ ″ ₁ (S38: YE
(S, S40: NO), although the fail determination flag Ehf is set (S43), as shown in FIG.
', The steering angular velocity theta' 8 absolute value of _H is 'determined whether ₅ hereinafter, then S40' predetermined value theta at, or yaw acceleration [psi "the absolute value of the predetermined reference value [psi" ₅ or less not It is determined that the absolute value of the yaw acceleration ψ ″ is larger than the predetermined reference value ψ ″ ₅ although the absolute value of the steering angular velocity θ ′ _H is equal to or smaller than the predetermined value θ ′ ₅ (S38 ′: (YES, S40 ': NO), the fail determination flag Ehf may be set (S43).

Next, the control of the rear wheel turning ratio variable mechanism 22 and the determination of the failure of the servomotor that drives it will be described.

As described above, the motor failure determining means 41 shown in FIG. 2 sets the threshold time (threshold time) when the servo motor starts driving the variable steering ratio mechanism 22.
Together with starting the timer 42 to K, compares the steering angle ratio steering ratio θS which is measured by the sensor 26, and a target steering ratio TGshita _S calculated in the steering ratio calculating means 38, threshold time even after the elapse of K is, when the difference between the measured steering angle ratio theta _S and the target steering ratio TGshita _S is not smaller than a predetermined value theta _S0, it is determined that the motor fail, two-wheel steering control (control mode B) Has been migrated to.

On the other hand, in the variable steering ratio mechanism 22 driven by the motor, since gears are interposed in the power transmission system, the rattle of the gears is reduced when the vehicle is running at a low speed where road noise and the like are reduced. Get to your ears. Therefore, in this embodiment, a servo motor is used as the drive motor of the variable steering ratio mechanism 22, and the time required to reach the target value can be changed. The motor responsiveness changing means 43 (see FIG. 2) Is provided to reduce the responsiveness of the servomotor as compared with that at high speed.

However, if the responsiveness of the servomotor is reduced at low speeds as described above, the time required to reach the target value becomes longer. Therefore, if the threshold time K is set to be constant regardless of the vehicle speed, In spite of the fact that there is no abnormality in the motor, it may be determined that the motor has failed at low speed.

Therefore, in this embodiment, the threshold time K is made longer at low speeds than at high speeds to avoid erroneous determination.

FIG. 10 is a flowchart showing a control routine of the turning ratio variable mechanism 22. FIG. 11 shows a map used for this control.

First, after the data is initialized (S
51), enter the vehicle speed V (S52), based on the map A of FIG. 8, determines a target steering ratio TGshita _S from the vehicle speed V (S
53). Next, based on the map B in FIG. 11, the pulse width Pw of the drive signal for driving the servomotor is determined from the vehicle speed V (S54).

As is apparent from Map B, the pulse width P
w decreases with a decrease in the vehicle speed V, whereby the responsiveness of the servomotor is lower at low speeds than at high speeds.

Next, based on the map C of FIG.
The threshold time K is determined from (step S55). As is apparent from the map C, the threshold time K is inversely proportional to the pulse width Pw, so that the threshold time K is longer at a low speed than at a high speed.

The variable steering ratio mechanism 2 is determined based on the pulse width Pw and the threshold time K determined as described above.
2 is started (S56), the timer 42 is reset, and time measurement is started (S57). Then, it is determined whether or not the threshold time K has elapsed (S58). Until the threshold time K is reached (S58: NO), the timer 42 is set.
It is incremented (S59), when the threshold time K has elapsed (S58: YES), the difference between the measured steering ratio θS and the target steering angle ratio TGshita _S is judged whether it is smaller than the predetermined value theta _S0 If the difference is smaller than the predetermined value θ _S0 (S60: YES), the process returns to S52. If the difference is equal to or larger than the predetermined value θ _S0 , it is determined that the motor has failed. The process proceeds to wheel steering control (control mode B).

In the above description, the method of judging a failure of the yaw rate sensor according to the present invention and the configuration and operation of the steering apparatus of the vehicle to which the method is applied have been clarified. However, the present invention is not limited to the steering apparatus of the vehicle. The present invention is also applicable to an ABS device and other traveling control devices for vehicles.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram showing the configuration of an embodiment of a vehicle steering system according to the present invention.

FIG. 2 is a block diagram of the steering device shown in FIG. 1;

FIG. 3 is a control block diagram showing the operation of the steering device shown in FIG. 1;

FIG. 4 is a diagram showing an estimated yaw acceleration calculation map;

FIG. 5 is a flowchart showing a control mode setting routine of the steering device shown in FIG. 1;

FIG. 6 is a flowchart showing a yaw rate sensor fail determination routine of FIG. 5;

FIG. 7 is a view showing a changed part in the flowchart of FIG. 6;

FIG. 8 is a view showing a changed part in the flowchart of FIG. 6;

9 is a view showing a changed part in the flowchart of FIG. 6;

FIG. 10 is a flowchart showing a drive control routine of the variable steering ratio mechanism of FIG. 1;

FIG. 11 is a diagram showing a map used in the control routine of FIG. 10;

FIG. 12 is a timing chart for explaining problems of a conventional steering device.

[Explanation of symbols]

 Reference Signs List 10 steering device 14 front wheel turning mechanism 20 rear wheel turning mechanism 22 variable turning ratio mechanism 24 control unit 25 steering angle sensor 26 turning ratio sensor 27 vehicle speed sensor 28 yaw rate sensor 31 steering angle speed calculating means 32 yaw acceleration calculating means 34 fail judgment Means 35 Estimated yaw acceleration calculation means 36 Yaw acceleration correction means 37 Control mode selection means 38 Turning ratio calculation means 40 Turning ratio control means

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification code FI B62D 113: 00 B62D 117: 00 117: 00 137: 00 137: 00 G01P 15/00 (72) Inventor Shosuke Ito Hiroki Aki No.3-1 Shinchi, Gunfu-cho Mazda Co., Ltd. (56) References JP-A-4-135976 (JP, A) JP-A-5-85136 (JP, A) JP-A-4-135980 (JP, A) (58) Field surveyed (Int.Cl. ⁷ , DB name) B62D 6/00 B62D 7/14

Claims (4)

(57) [Claims] A steering angle sensor for detecting a steering angle of a steering wheel;
A travel control for a vehicle, comprising: a yaw rate sensor for detecting a yaw rate; travel control means controlled based on at least the steering angle and yaw rate detected by these sensors; and failure determination means for determining a failure of the yaw rate sensor. The device estimates the steering angle from the steering angle detected by the steering angle sensor.
An estimated yaw acceleration calculating means for calculating a yaw acceleration, wherein the failure determining means detects that the data relating to the steering wheel angle detected by the steering angle sensor is equal to or greater than a first predetermined value and is detected by the yaw rate sensor When the state in which the data relating to the yaw rate becomes smaller than the second predetermined value continues for the first predetermined time, it is determined that a failure has occurred. Is used for controlling the traveling control means, and the second point is determined from the point in time when the failure determination means determines that a failure has occurred.
Until the fixed time elapses, the estimated yaw acceleration calculating means
The estimated yaw acceleration calculated by
A travel control device for a vehicle, which is used for control. 2. A steering angle sensor for detecting a steering angle of a steering wheel,
A travel control for a vehicle, comprising: a yaw rate sensor for detecting a yaw rate; travel control means controlled based on at least the steering angle and yaw rate detected by these sensors; and failure determination means for determining a failure of the yaw rate sensor. The device estimates the steering angle from the steering angle detected by the steering angle sensor.
An estimated yaw acceleration calculating means for calculating a yaw acceleration, wherein the failure determination means detects that the data related to the steering wheel angle detected by the steering angle sensor is equal to or less than a third predetermined value and is detected by the yaw rate sensor When the state in which the data regarding the yaw rate becomes larger than the fourth predetermined value continues for the first predetermined time, it is determined that a failure has occurred. Is used for controlling the traveling control means, and the second point is determined from the point in time when the failure determination means determines that a failure has occurred.
Until the fixed time elapses, the estimated yaw acceleration calculating means
The estimated yaw acceleration calculated by
A travel control device for a vehicle, which is used for control. A steering angle sensor for detecting a steering angle of the steering wheel;
A yaw rate sensor that detects the yaw rate and these sensors
The steering angle and yaw rate detected by the
Traveling control means controlled on the basis of
Vehicle with failure determination means for determining failure of the sensor
In the traveling control device, the yaw rate detected by the yaw rate sensor
An actual yaw acceleration calculating means for calculating an actual yaw acceleration;
Estimated yaw from steering wheel angle detected by steering angle sensor
Estimated yaw acceleration calculating means for calculating the acceleration, wherein the failure determination means detects the yaw acceleration by the steering angle sensor.
The data regarding the steering angle of the steering wheel is greater than the first predetermined value.
And the yaw rate detected by the yaw rate sensor.
Data about the chart is smaller than the second predetermined value
When the state has continued for the first predetermined time, it is determined that the state has failed.
Is configured, the above failure determination means until the time determines that failure, upper
The data relating to the yaw rate is controlled by the travel control means.
And when the failure determination means determines a failure,
Actual yaw acceleration calculated by the actual yaw acceleration calculating means
Degree and estimation calculated by the estimated yaw acceleration calculation means
When the difference from the yaw acceleration is equal to or greater than a fifth predetermined value,
From the point in time when the failure determination means determines that the
Until the fixed time has elapsed, the estimated yaw acceleration
The vehicle is characterized by being used for controlling line control means.
Travel control device. A steering angle sensor for detecting a steering angle of the steering wheel;
A yaw rate sensor that detects the yaw rate and these sensors
The steering angle and yaw rate detected by the
Traveling control means controlled on the basis of
Vehicle with failure determination means for determining failure of the sensor
In the traveling control device, the yaw rate detected by the yaw rate sensor
An actual yaw acceleration calculating means for calculating an actual yaw acceleration;
Estimated yaw from steering wheel angle detected by steering angle sensor
Estimated yaw acceleration calculating means for calculating the acceleration, wherein the failure determination means detects the yaw acceleration by the steering angle sensor.
When the data related to the steering angle is less than the third predetermined value.
And the yaw rate detected by the yaw rate sensor.
The data on the chart has become larger than the fourth predetermined value
When the state has continued for the first predetermined time, it is determined that the state has failed.
Is configured, the above failure determination means until the time determines that failure, upper
The data relating to the yaw rate is controlled by the travel control means.
And when the failure determination means determines a failure,
Actual yaw acceleration calculated by the actual yaw acceleration calculating means
Degree and estimation calculated by the estimated yaw acceleration calculation means
When the difference from the yaw acceleration is equal to or greater than a fifth predetermined value,
From the point in time when the failure determination means determines that the
Until the fixed time has elapsed, the estimated yaw acceleration
The vehicle is characterized by being used for controlling line control means.
Travel control device.