JP2001171501A - Vehicle behavior controller - Google Patents

Abstract

PROBLEM TO BE SOLVED: To detect speedily abnormality of a sensor such as a yaw rate sensor and a steering angle sensor. SOLUTION: During controlling of a yaw rate, an adjusting direction of the yaw moment exerted to a vehicle is compared with a steering direction of a driver by providing, for example, braking force. When both the directions are opposite to each other, a sensor is decided to be abnormal.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention detects a physical quantity including at least a steering angle, and adjusts a yaw moment generated in a vehicle based on a deviation between a target yaw rate obtained from the detected physical quantity and an actual yaw rate detected. The present invention relates to a vehicle behavior control device that controls a vehicle behavior by doing so.

[0002]

2. Description of the Related Art As disclosed in Japanese Patent Application Laid-Open Nos. Hei 2-70561, Hei 10-67242 and Hei 11-48925, a vehicle behavior control device of this type is used as a physical quantity of a vehicle. Detects the angle and vehicle speed, sets the target value of the yaw rate as the vehicle behavior based on them, and detects the actual value of the yaw rate generated in the vehicle, and sets the target value of the actual value of the yaw rate according to the deviation between the two. The braking fluid pressure to the braking wheel cylinder is controlled to obtain a force that matches the value. For example, when the vehicle tends to oversteer, the brake wheel cylinder on the outside of the turn is increased in pressure compared to the inside of the brake, and when the vehicle tends to understeer, the brake wheel cylinder on the outside of the turn is increased in pressure compared to the inside of the turn. . That is, in order to control the vehicle behavior in the lateral direction including the yawing motion by such a vehicle behavior control device, generally, the fluid pressure of the brake wheel cylinder of each wheel is controlled to control the yaw generated in the vehicle. Adjusting the moment.

By the way, when such vehicle behavior control is performed, sensors for detecting each physical quantity such as the yaw rate and the steering angle described above are monitored. It is necessary to perform failsafe promptly. As a method of detecting an abnormality of sensors of such a vehicle behavior control device, for example, Japanese Patent Laid-Open No. 7-149
251 and Japanese Patent Application Laid-Open No. 9-2317. In both cases, when the difference between the estimated value of the yaw rate obtained from the physical quantity such as the steering angle or the wheel speed and the yaw rate actually detected by the yaw rate sensor is equal to or larger than the reference value, it is determined that the yaw rate sensor is abnormal. Is what you do.

[0004]

However, in order to determine that the yaw rate sensor is abnormal when the difference between the estimated value and the actual value of the yaw rate is equal to or larger than a predetermined value, there is a certain state. If it does not last to a certain extent, accurate judgment cannot be made. For example, when there is a so-called μ jump in which the friction coefficient state of the road surface (hereinafter also simply referred to as μ) changes rapidly, for example, during a turn from a dry road to a frozen road, the so-called μ jump, the estimated value of the yaw rate and the actual Is very different. Of course, immediately after that, for example, the vehicle behavior device should operate to eliminate the difference between the two, but the vehicle behavior actually changes, and as a result, the difference between the estimated value and the actual value of the yaw rate becomes small. , Μ, a short time has elapsed since the jump, and in such a case, it is necessary to determine the abnormality of the yaw rate sensor for a time longer than the time required until the control result becomes clear. . That is, there is a problem that it takes time to detect the abnormality of various sensors.

The present invention has been developed in view of these problems, and provides a vehicle behavior control device capable of quickly detecting an abnormality of various sensors such as a yaw rate sensor and a steering angle sensor. It is intended for.

[0006]

According to the present invention, there is provided a vehicle behavior control apparatus according to a first aspect of the present invention, comprising a sensor for detecting a physical quantity of a vehicle including at least a steering angle of a steered wheel. Detecting means, a yaw rate detecting means having a sensor for detecting a yaw rate generated in the vehicle, and setting a target yaw rate by using at least a steering angle detected by the physical quantity detecting means, at least the target yaw rate and the yaw rate detecting means A control means for adjusting the yaw moment generated in the vehicle in accordance with the deviation from the yaw rate detected in step (a) to control the lateral behavior of the vehicle. The direction of the moment is opposite to the direction of the yaw moment due to the driver's steering obtained from the steering angle detected by the steering angle detection means. Is characterized in that one or both of the sensors of the yaw rate detection means or a physical quantity detecting means with a sensor abnormality detecting means determines that abnormal when it is.

According to a second aspect of the present invention, there is provided a vehicle behavior control device according to the first aspect, wherein each wheel includes a braking wheel cylinder, and the control means includes a braking wheel cylinder for each wheel. When the yaw moment of the vehicle is adjusted by controlling the fluid pressure of
The sensor abnormality detecting means may include the yaw rate detecting means or the steering angle physical quantity when the control means is increasing the fluid pressure of at least the front right wheel cylinder, and when the driver's steering direction is the left direction. It is characterized in that it is determined that one or both of the detection means are abnormal.

According to a third aspect of the present invention, in the vehicle behavior control device according to the first aspect, each wheel is provided with a braking wheel cylinder, and the control means includes a braking wheel cylinder for each wheel. When the yaw moment of the vehicle is adjusted by controlling the fluid pressure of
The sensor abnormality detection unit is configured to control the yaw rate detection unit or the physical quantity detection unit when the control unit increases the fluid pressure of at least the front left wheel cylinder, and when the driver's steering direction is rightward. It is characterized in that one or both sensors are determined to be abnormal.

According to a fourth aspect of the present invention, there is provided a vehicle behavior control device according to the first aspect, wherein each wheel is provided with a braking wheel cylinder, and the control means comprises a braking wheel cylinder for each wheel. When the yaw moment of the vehicle is adjusted by controlling the fluid pressure of
The sensor abnormality detecting means includes a yaw rate detecting means or a physical quantity detecting means when the control means is increasing the fluid pressure of at least the rear right wheel cylinder, and when the driver's steering direction is the left direction. It is determined that one or both of the sensors are abnormal.

According to a fifth aspect of the present invention, there is provided a vehicle behavior control device according to the first aspect, wherein each wheel is provided with a braking wheel cylinder, and the control means comprises a braking wheel cylinder for each wheel. When the yaw moment of the vehicle is adjusted by controlling the fluid pressure of
The sensor abnormality detection unit is configured to control the yaw rate detection unit or the physical quantity detection unit when the driver's steering direction is rightward while the control unit is increasing the fluid pressure of at least the rear left wheel cylinder. It is characterized in that one or both sensors are determined to be abnormal.

[0011]

According to the vehicle behavior control apparatus according to the first aspect of the present invention, the yaw moment direction adjusted by the control means and the steering angle detected by the steering angle detection means are determined. When the direction of the yaw moment caused by the driver's steering is in the opposite direction, one or both of the yaw rate detection means and the physical quantity detection means are determined to be abnormal, so that the vehicle behavior control results , The time required for detecting a sensor abnormality can be reduced by that amount, and the abnormality can be quickly detected.

According to the vehicle behavior control device of the present invention, the yaw moment of the vehicle is adjusted by controlling the fluid pressure of the braking wheel cylinder of each wheel. Since the sensor abnormality is determined from the relationship between the wheel cylinder being pressure-intensified and the driver's steering direction, the sensor abnormality detection is easily determined, and the sensor abnormality is quickly detected by that much. In addition, the calculation load can be reduced.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a vehicle behavior control device according to the present invention will be described below with reference to the accompanying drawings. FIG.
1 is a brake fluid pressure / electric system diagram showing an outline of a brake fluid pressure control device as a vehicle behavior control device of the present embodiment. Reference numerals 1FL and 1RR in the figure indicate a front left wheel and a rear right wheel, respectively.
FR and 1RL indicate a front right wheel and a rear left wheel, respectively. The corresponding wheel cylinders 2FL to 2RR as braking cylinders are attached to the respective wheels 1FL to 1RR. In addition, each wheel cylinder 2FL-2R
R is a so-called disc brake which presses a pad against a disc rotor to perform braking.

The master cylinder 5 generates two systems of master cylinder pressure in response to the depression of the brake pedal 4.
The connection structure with each of the wheel cylinders 2FL to 2RR is such that the front left wheel cylinder 2FL and the rear right wheel cylinder 2RR are connected to one system of the master cylinder 5,
A piping structure called the diagonal split piping or X piping, which connects the front right wheel cylinder 2FR and the rear left wheel cylinder 2RL to the other system. Then, for each system of the master cylinder pressure of the master cylinder 5, the master cylinder 5 and the wheel cylinder 2FL,
The master cylinder disconnecting valves 6A and 6B for connecting and disconnecting 2RR or 2FR and 2RL are interposed.

A pressure boosting pump 3 for pressurizing the brake fluid in the master cylinder reservoir 5a is separately provided, and the discharge pressure of the pressure boosting pump 3 is branched into two, so that the two master systems from the master cylinder 5 are separated. The cylinder pressure is merged downstream of the master cylinder on-off valves 6A, 6B, that is, on the side of each of the wheel cylinders 2FL to 2RR. In addition, between each confluence point and the pump 3 for boosting, the pump 3 for boosting and the wheel cylinder 2FL, 2RR or 2FR, 2FR, 2
The pressure increasing / disconnecting pump interrupting valves 7A and 7B for interrupting connection with the RL are provided.

One system of the master cylinder 5 or one system branched from the pressure increasing pump 3 is regarded as one system of the brake fluid pressure source, and the wheel cylinders 2FL, 2RR or 2FR, 2RL connected thereto are regarded as one system. Pressure increase control valves 8FL, 8RR or 8 corresponding to the respective upstream sides of
FR, 8RL is interposed. Note that these pressure increase control valves 8
FL, 8RR or 8FR, 8RL are provided with check valves 9FL, 9RR or 9FR, 9RL in their respective bypass flow paths, and when the depression of the brake pedal is released, the inside of the wheel cylinders 2FL, 2RR or 2FR, 2RL is provided. The braking fluid is immediately returned to the master cylinder 5 side.

Further, the discharge sides of the individual pressure reducing pumps 11A and 11B are connected to the respective systems of the braking fluid pressure sources, and their suction sides are connected to the wheel cylinders 2FL and 2RR.
Alternatively, the pressure reduction control valve 10FL, 10
RR or 10FR, 10RL is interposed. The two pressure reducing pumps 11A and 11B also serve as one pump motor. In addition, reservoirs 18A and 18B for preventing interference are connected between the decompression control valves 10FL and 10RR or 10FR and 10RL and the decompression pumps 11A and 11B.

Each of these pressure control valves is controlled by a control described later.
Switchable by drive signal from roll unit
Position switching valves, which are fail safe,
For example, master cylinder intermittent valves 6A and 6B are always open,
Pump shut-off valves 7A and 7B are always closed, and pressure increase control valve 8F
L, 8RR or 8FR, 8RL is always open, pressure reducing control valve 1
0FL, 10RR or 10FR, 10RL is normally closed.
Each solenoid 6 is driven by the drive signal.
A_SOL, 6B_SOL, 7A_SOL, 7B_SOL, 8FL_SOL,
8RR_SOL, 8FR_SOL, 8RL_SOL, 10FL_SOL,
10RR_SOL, 10FR _SOL, 10RL_SOLIs excited
Then, the state is switched to the opposite open / close state. In addition, the pressure boosting pon
Control unit 3 and decompression pumps 11A and 11B
The drive is controlled by a drive signal from the unit.

Therefore, in this braking fluid pressure circuit, when controlling the braking force for performing the vehicle behavior control described later, the braking fluid pressure (hereinafter also referred to as wheel cylinder pressure) of each of the wheel cylinders 2FL to 2RR is increased. In this case, for example, the pressure increasing pump 3 is driven with the master cylinder on-off valves 6A and 6B closed and the pressure-increasing pump on-off valves 7A and 7B open, and the generated pressure is reduced by the pressure reduction control valves 10A and 6B.
With the FL-10RR closed, the pressure increase control valves 8FL-8RR
Is controlled to open and supply to each of the wheel cylinders 2FL to 2RR.

Each of the wheel cylinders 2FL-2FL
When each wheel cylinder pressure is to be reduced after the RR wheel cylinder pressure is increased, for example, the master cylinder disconnection valves 6A and 6B are closed, and the pressure increase pump disconnection valves 7A and 7B are closed. , 11B, and while the pressure increase control valves 8FL to 8RR are closed, the pressure reduction control valves 10FL to 10RR are controlled to open to discharge the brake fluid in the wheel cylinders 2FL to 2RR.

The opening control of each of the pressure increase control valves 8FL to 8RR and the pressure reduction control valves 10FL to 10RR will be described later. Further, in order to reduce the reaction force to the brake pedal 4, when the brake pedal 4 is depressed, the master cylinder on-off valves 6A and 6B may be opened. On the other hand, as shown in FIG. 1, each of the wheels 1FL to 1RR has a sine wave corresponding to the wheel speed in order to detect a wheel speed (hereinafter also referred to as a wheel speed) corresponding to the rotation speed of the wheel. Wheel speed sensors 12FL to 12RR for outputting signals
Is installed.

In the vehicle, a yaw rate sensor 13 for detecting an actual yaw rate ψ ′ generated in the vehicle, a steering angle sensor 14 for detecting a steering angle θ of a steered wheel from a steering angle of a steering wheel, an acceleration sensor 15 for detecting a lateral acceleration and longitudinal acceleration and master cylinder pressure sensor 1 that detects the master cylinder pressure P _MC of the two systems
6 and, if necessary, a brake switch for detecting the depressed state of the brake pedal 4 and outputting a brake signal, and the like, and the detection signals of each sensor and switch are input to a control unit 17 described later. The actual yaw rate ψ ′ from the yaw rate sensor 13 and the steering angle θ from the steering angle sensor 14 have, for example, positive and negative directions, but between them, for example, when the steering wheel is turned right. The steering angle is set so that the directionality of the clockwise yaw rate generated at that time matches.
Here, the steering angle θ and the actual yaw rate ψ ′ are positive values when the steering wheel is turned left, and negative values when turned right. The brake signal from the brake switch 4a is, for example, a digital signal having a logical value "1" indicating an ON state when the brake pedal is depressed and a logical value "0" indicating an OFF state when the brake pedal is not depressed. But also.

The control unit 17 receives a detection signal from each of the aforementioned sensors and switches, and outputs a control signal to each of the switching valves.
And a drive circuit for converting a control signal output from the microcomputer into a drive signal for each control valve solenoid including an electromagnetic switching valve as described above. The microcomputer includes an input interface circuit having an A / D conversion function, an output interface circuit having a D / A conversion function, an arithmetic processing device including a microprocessor unit MPU, a ROM, an R
It has a storage device such as an AM. Since the operating frequency of the microcomputer is very high, the microcomputer outputs a reference rectangular wave control signal of pulse width modulated digital data, and each drive circuit simply outputs the control signal to each actuator. It is configured to only convert and amplify a drive signal suitable for the device. Further, in the microcomputer,
It is responsible not only for generating and outputting the main control signals necessary for the various controls as described above, but also, for example, for controlling the drive of the pressure reducing pump required for the pressure reduction control in the vehicle behavior control and for supplying power to the actuator itself. It goes without saying that the control signal to the switch element of the actuator relay is also generated and output in parallel.

Next, the arithmetic processing of the brake fluid pressure control executed by the microcomputer in the control unit 17 to control the yawing momentum of the vehicle will be described with reference to the flowcharts in the accompanying drawings. Although no particular communication step is provided in this arithmetic processing, programs and maps stored in the ROM of the storage device in the microcomputer or various data stored in the RAM are always subjected to arithmetic processing. Each calculation result transmitted to a buffer or the like of the device and calculated by the arithmetic processing device is also stored in the storage device at any time.

First, FIG. 2 shows an overall flow of the braking force control, a so-called general flow. This arithmetic processing is executed as a timer interrupt at every predetermined control time ΔT of, for example, 10 msec. First, in step S1, based on the sine wave signals from the wheel speed sensors 12FL to 12RR, individual processing is performed in the same step. the arithmetic processing, and calculates the wheel speeds _{Vw i (i = FL, FR} , RLorRR) a. More specifically, in the case where the wheel speed sensors 12FL to 12RR are, for example, those described in Japanese Patent Application Laid-Open No. 7-329759 previously proposed by the present applicant, the wheel speed sensors 12FL to 12RR are set in advance. The sine wave signal from 3FL to 3R is shaped into a rectangular wave signal, and Lo / Hi of the rectangular wave signal is read in a short sampling cycle to determine the pulse width of the rectangular wave signal. to calculate the Vw _i. That is, the pulse width of the waveform-shaped rectangular wave signal the larger the wheel speed Vw _i is the shorter, the pulse width becomes longer the smaller the wheel speed Vw _i. Since the pulse width of the rectangular wave signal is equivalent to the time required for the tooth of a predetermined length of the sensor to pass as described above, the pulse width is inversely proportional to the rotational angular velocity of each wheel. if the pulse width is obtained, the rotational angular velocity of each wheel is determined, the wheel speeds Vw _i multiplied by the dynamic rolling radius tire to the rotating angular velocity is calculated. Of course, it is possible to calculate similarly the wheel speed Vw _i be a conventional method of obtaining the wheel rotational angular velocity by several pulses within a predetermined time is counted.

Next, the process proceeds to step S2, where the detection signals from the respective sensors are read by the individual arithmetic processing performed in the step. At the next step S3, for example, the applicant, as described in Japanese Patent Laid-Open No. 8-150920 previously proposed, calculate the estimated vehicle speed V _X by each individual arithmetic process to be executed in the step I do. In addition,
Arithmetically processed as is described in this publication, but is configured for calculating the estimated vehicle speed V _X without using the longitudinal acceleration, since in the present embodiment detects the longitudinal acceleration by the acceleration sensor 15, the value The correction may be performed using the above.

Next, the process proceeds to step S4, where the individual acceleration processing performed in the step, for example, the lateral acceleration Y _G from the acceleration sensor 15 and the estimated vehicle speed V
_{From the X} and the actual yaw rate ψ ′ from the yaw rate sensor 13, the vehicle side slip acceleration β _dd is calculated according to the following equation (1). β _dd = Y _G −V _X ψ ′ (1) Next, the process proceeds to step S5, and the skid acceleration β _{dd of the} vehicle is calculated by a calculation process such as a low-pass filter process in which the phase is appropriately set. Is integrated over time to calculate the skid speed β _d
Is calculated.

Next, the process proceeds to step S6,
Due to the individual calculation processing performed in the
Speed β_dAnd estimated vehicle speed V_XRatio β_d/ V_XFrom the vehicle
Is calculated. Next, the process proceeds to step S7.
For example, Japanese Unexamined Patent Publication No. Hei.
No. 8 discloses an arithmetic processing using a vehicle model.
Target yaw rateψ ^'*Is calculated. Note that the target Yawley
To^'*Is the pre-set cornering for each wheel
G force, which results in the vehicle being in neutral
The yaw rate achieved when turning
You. This target yaw rate ψ^'*In calculating the
If the angle divided by the steering gear ratio is the steering angle θ,
It should just be used. Also, the estimated vehicle speed V_XAnd steering angle θ
May be obtained from the map.

Next, the process proceeds to step S8, in which the vehicle is calculated from the deviation between the target yaw rate ψ ^'* and the actual yaw rate ψ', ie, the target yaw rate deviation Δψ ^'*, etc., by individual calculation processing performed in the step. The behavior state value X is calculated. The vehicle behavior state value X is, for example, in a strong oversteer state in which the actual yaw rate ψ ′ is significantly larger than the target yaw rate ψ ^{′ *} and the side slip angle β and the side slip speed β _d are small using the target yaw rate deviation Δψ ^{′ *.} This is a value for evaluating vehicle behavior such as a certain or a real understeer state in which the actual yaw rate ψ ′ is significantly smaller than the target yaw rate ψ ^{′ *} and the side slip angle β and the side slip speed β _d are large.

Next, the process proceeds to step S9, and the individual wheels 1FL to 1R are calculated by the individual calculation processing performed in the step according to the vehicle behavior state value X obtained in step S8.
The target wheel cylinder pressure P ^* _0-i of the wheel cylinders 2FL to 2RR of R is calculated. The target wheel cylinder pressure P ^* _0-i is determined by, for example, making the actual yaw rate ψ ′ coincide with the target yaw rate ψ ^{′ *} , or adjusting the side slip angle β and the side slip speed β _d to the predetermined target values. This is for generating a braking force difference between the wheels.For example, a braking force difference is obtained from a linear sum obtained by adding a control gain to the target yaw rate deviation Δψ ^{′ *} , the sideslip angle deviation or the sideslip speed deviation, and this is used as a braking fluid. substituted on pressure difference may be as represented by the wheel cylinder pressure P _i.

Next, the process proceeds to step S10, where it is determined whether or not the vehicle behavior control condition is satisfied by the individual arithmetic processing performed in the step. The process moves to step S11; otherwise, the process moves to step S12. The vehicle behavior control condition is, for example, that the target yaw rate deviation Δψ ^{′ *} is greater than a predetermined value or that the side slip angle β
And side slip velocity β _d can be carried out in the evaluation, such as too small Toka too large with respect to the target value.

In step S11, vehicle behavior control,
In particular, here, the yaw rate control flag F _YAW is set to “1” assuming that the yaw rate control is performed, and then the step S
Go to step 13. In step S13, a vehicle behavior control content flag is set according to the table in Table 1 below according to the current vehicle behavior, for example, in which direction the vehicle is turning and oversteering or understeering. Then, the process proceeds to step S14. That is, there is an understeer when turning left (U.
When performing S) suppression control, as shown in Figure 3a, because it gives a braking force to the rear left wheel primarily set to "1" to the left understeer control flag F _USL. Also, when performing oversteer (OS in the figure and table) suppression control during a left turn, as shown in FIG. 3B, a braking force is mainly applied to the front right wheel, so that the right oversteer control flag F _OSR
Is set to “1”. When the oversteer suppression control is performed during a right turn, the braking force is mainly applied to the front left wheel, so the left oversteer control flag F _OSL is set to “1”. Also, if there during rightward turning perform understeer suppression control, because it gives a braking force to the rear right wheel primarily set to the right understeer control flag F _USR "1". By the way, flags that are not set are cleared.

[0033]

[Table 1]

In step S14, the current estimated wheel cylinder pressure _Pi is calculated by the individual arithmetic processing performed in step S14, and then the process proceeds to step S15. Specifically, in step S14, the control of the wheel cylinder pressure has already been started for vehicle behavior control, and the control amount, that is, the wheel cylinder pressure increase / decrease amount, is grasped in the microcomputer as described later. Therefore, for example, the master cylinder pressure when the vehicle behavior control is started may be set as an initial value, and the wheel cylinder pressure increase / decrease amount of the previous control time may be accumulated and tracked.

In step S15, the achieved wheel cylinder pressure P ^* _i is calculated based on the target wheel cylinder pressure P ^* _0-i in accordance with the individual arithmetic processing performed in step S15, and the process proceeds to step S16. The achieved wheel cylinder pressure P ^* _i is set, for example, according to the convergence state of the yaw rate after the vehicle behavior control is started. For example, there is no sign that the yaw rate converges while the control is started. Sometimes, for example, the yaw rate is guided in a converging direction by reducing the wheel cylinder pressure of the turning inner wheel.

In step S16, within the same step
The individual wheel operations performed by the
Pressure increase / decrease amount ΔP^* _iAccording to the above
Control valves 8FL to 8RR or pressure reducing control valves 10FL to 10RR
Calculates solenoid excitation drive pulse duty ratio for
Then, the process proceeds to step S17. Specifically, each car
The pressure increase control valve 8FL to 8RR or the pressure decrease control valve 1
To control the opening and closing of any of 0FL to 10RR,
Renoid 8FL_SOL~ 8RR_SOLOr 10FL _SOL~ 1
0RR_SOLOf which is excited and at what time rate (or
Is a non-excitation state?)
Calculate the loose duty ratio. In other words, this control tie
Achieved wheel cylinder pressure increase and decrease ΔP^* _iBut
As can be obtained, the pressure increase control valves 8FL-8
When RR or any one of the pressure reduction control valves 10FL to 10RR is opened
The time ratio for controlling the duty ratio of the drive pulse
Is calculated as

In step S17, the solenoid excitation drive pulse control signal corresponding to the duty ratio is generated and output by the individual arithmetic processing performed in step S17, and then the process returns to the main program. The generation of the drive pulse signal according to the duty ratio is based on the conventional PW
Since it is the same as M (Pulse Width Modulation) control, detailed description is omitted.

On the other hand, in the step S12, the yaw rate control flag F _YAW is cleared to "0", and then the process _proceeds to a step S18. In step S18, the process returns to the main program after clearing all the vehicle behavior control content flags. Next, the individual arithmetic processing in FIG. 4 performed in parallel with the arithmetic processing in FIG. 2 will be described. The arithmetic processing of FIG. 4 is performed in the same control cycle as the arithmetic processing of FIG. In this calculation process, first, in step S21, the steering angle θ is read.

Next, the process proceeds to step S22, for example,
The yaw rate control flag F_YAWIs set
Which yaw rate is being controlled
If the yaw rate control is being performed, the process proceeds to step S23.
The process proceeds to step S24 otherwise.
You. In the step S23, according to Table 2 below,
Abnormal judgment of sensors such as yaw rate sensor and steering angle sensor
Perform settings. That is, the right oversteer control flag F _OSR
Is in the set state, and the steering angle θ is a positive value,
It is abnormal when the alling wheel is turned left.
Is determined. Further, the left oversteer control flag F
_OSLIs in the set state, and the steering angle θ is a negative value, that is,
Abnormal when steering wheel is turned right
Is determined. The right understeer control flag
F_USRIs in the set state and the steering angle θ is a positive value
Is determined to be abnormal. Also, the left understeer
Control flag F_USLIs set, and the steering angle θ is a negative value.
At some point, it is determined to be abnormal. As a result, the sensor
When an abnormality is detected in the class, the process proceeds to step S25.
If it is determined that the operation is normal, the process proceeds to step S2.
Move to 4.

[0040]

[Table 2]

In step S25, the abnormality determination timer _TSF is incremented, and the process proceeds to step S26. In step S26, the abnormality determination timer T _SF
Is determined to be greater than or equal to a predetermined value _TF , and if the abnormality determination timer _TSF is greater than or equal to the predetermined value _TF , step S
Then, the process returns to step 27, and otherwise returns to the main program.

In step S27, the processing at the time of abnormality of the sensors is performed by the individual arithmetic processing performed in the same step, and then the process returns to the main program. In addition, in the case of sensor abnormality processing, so-called fail-safe is performed, which eventually stops vehicle behavior control, but before that, the sensor abnormality determination as described in the related art is performed, Alternatively, the control force may be temporarily reduced, and the abnormality determination of the sensor may be performed again.

For example, FIG. 5 shows the output value of the yaw rate sensor when the vehicle slips over while traveling straight and the vehicle is oversteered, and the state of steering by the driver. In this case, step S1 of the arithmetic processing of FIG.
0, the output value of the yaw rate sensor is equal to the steering angle θ.
The yaw rate control is performed only while the threshold value of the oversteer control set according to is exceeded. At this time, it can be understood that the driver is steering the steering wheel in the direction opposite to the direction in which the yaw rate is excessive. FIG.
This shows a state in which the vehicle is oversteered while turning left. In such oversteer suppression control when turning left,
A braking force is mainly applied to the front right wheel, and this braking force causes the vehicle to generate a clockwise yaw moment in a plan view. That is, in this case, the clockwise yaw moment is added so as to suppress the counterclockwise yaw moment which is too large in plan view. However, irrespective of the presence or absence of this control force, the driver attempts to correct the oversteer by performing so-called counter steering, in which the steering wheel is steered in the direction opposite to the turning. That is, if the output value of the yaw rate sensor is correct, the steering wheel is steered in the same direction as the control force, that is, the yaw moment adjustment direction.

On the other hand, FIG. 7 shows a state in which the yaw rate sensor suddenly becomes abnormal while the vehicle is traveling straight, and keeps outputting a constant positive output value. The control force is generated simultaneously with the abnormality of the yaw rate sensor. In this case, since the output value continuously output by the yaw rate sensor is a positive value, the control force acts in a negative value direction. However, the driver is steering the steering wheel in the opposite direction. FIG. 8 shows that the yaw rate sensor suddenly becomes abnormal during the left turn as in FIG.
As in FIG. 7, a state in which a positive output value is output is shown. In this case as well, a braking force is applied to the front right wheel to add a clockwise yaw moment in plan view, but as a result, the vehicle tends to understeer, and the driver is forced to turn the steering wheel to the left. . That is, when the output value of the yaw rate sensor is incorrect, that is, when the yaw rate sensor is abnormal, the steering wheel is steered in the direction opposite to the control force, that is, the direction in which the yaw moment is adjusted.

FIG. 9 shows an understeer during a left turn,
This shows a state in which a braking force is applied to the rear left wheel to apply a yaw moment counterclockwise in plan view. At this time, the driver intends to correct the understeer by turning the steering wheel to the left, that is, turning the steering wheel further, regardless of the presence or absence of the control force. Also in this case, if the output value of the yaw rate sensor is correct, the driver steers the steering wheel in the same direction as the yaw moment adjustment direction.

On the other hand, FIG. 10 shows a case where the yaw rate sensor becomes abnormal. In this case, although the vehicle itself does not tend to understeer, the yaw rate sensor outputs a negative output value, that is, outputs an output value as if it were understeer. Therefore, similarly to FIG. 9, a braking force is applied to the rear left wheel to apply a yaw moment counterclockwise in plan view, but as a result, the vehicle tends to oversteer, and the driver is forced to turn the steering wheel to the right. Cut off and perform counter steer. That is, when the output value of the yaw rate sensor is incorrect, that is, when the yaw rate sensor is abnormal, the steering wheel is steered in the direction opposite to the control force, that is, the direction in which the yaw moment is adjusted.

Such a tendency similarly occurs when, for example, the steering angle sensor becomes abnormal in addition to the yaw rate sensor. Further, when other physical quantities are taken into the vehicle behavior to be controlled, the same may occur when sensors for detecting those physical quantities become abnormal. Therefore, in the present embodiment, the state of the vehicle and the state of the steering angle are compared based on the yaw rate control content flag during the yaw rate control in step S23 of the calculation processing in FIG. When the direction and the steering direction of the steering wheel by the driver are opposite, the abnormality determination timer _TSF is incremented in step S25, and the abnormality determination timer _TSF is incremented by a predetermined value _{TF in} step S26.
When it is determined that the above is the case, the process proceeds to step S27, and the abnormality processing of the sensor is performed.

As described above, the wheel speed sensor 1 shown in FIG.
2FL to 12RR, steering angle sensor 14, acceleration sensor 1
5. Step S of the pressure sensor 16 and the calculation processing of FIG.
1. Step S2 constitutes a physical quantity detecting means, and similarly, the yaw rate sensor 13 shown in FIG. 1 and step S2 of the arithmetic processing in FIG.
The whole arithmetic processing of FIG. 2 constitutes the control means, and the whole arithmetic processing of FIG. 4 constitutes the sensor abnormality detecting means.

In the first embodiment, the direction of steering by the driver is determined by simply turning left or right from the positive or negative of the steering angle θ, ie, from a neutral neutral state.
In consideration of a turning state or the like, the steering direction at the time when the control force is generated, that is, whether the vehicle is currently steering left or right may be used. However, the control force is generated by oversteering, for example, in a situation where countersteering is actually applied or not, so that there is no problem even in the determination criteria as in the first embodiment.

In the above embodiment, the case where a microcomputer is used as the control unit has been described. Alternatively, an electronic circuit such as a counter and a comparator may be combined. Further, in the above embodiment, the yaw rate is used as the control vehicle behavior, but other vehicle behaviors may be controlled simultaneously.

[Brief description of the drawings]

FIG. 1 is a system diagram showing an embodiment of the present invention.

FIG. 2 is a flowchart illustrating an example of a calculation process executed in the control unit of FIG. 1;

FIG. 3 is an explanatory diagram of vehicle behavior control performed in the calculation processing of FIG. 2;

FIG. 4 is a flowchart illustrating an embodiment of a calculation process for detecting a sensor abnormality executed in the control unit of FIG. 1;

FIG. 5 is an explanatory diagram of a relationship between a yaw rate and a steering angle when a yaw rate sensor is normal.

FIG. 6 is an explanatory diagram of a relationship between a vehicle behavior when a yaw rate sensor is normal, a yaw moment due to a control force, and a steering direction by a driver.

FIG. 7 is an explanatory diagram of a relationship between a yaw rate and a steering angle when a yaw rate sensor is abnormal.

FIG. 8 is an explanatory diagram of a relationship between a vehicle behavior when a yaw rate sensor is abnormal, a yaw moment due to a control force, and a steering direction by a driver.

FIG. 9 is a diagram illustrating the relationship between the vehicle behavior when the yaw rate sensor is normal, the yaw moment due to the control force, and the steering direction by the driver.

FIG. 10 is an explanatory diagram of a relationship between a vehicle behavior when a yaw rate sensor is abnormal, a yaw moment due to a control force, and a steering direction by a driver.

[Explanation of symbols]

 1FL to 1RR are wheels 2FL to 2RR are wheel cylinders 3 are pressure boosting pumps 4 are brake pedals 5 are master cylinders 6A and 6B are master cylinder interrupting valves 7A and 7B are pressure increasing pump interrupting valves 8FL to 8RR are pressure increasing control valves 9FL. 9RR is a check valve 10FL-19RR is a pressure reduction control valve 11A, 11B is a pressure reduction pump 12FL-12RR is a wheel speed sensor 13 is a yaw rate sensor 14 is a steering angle sensor 15 is an acceleration sensor 17 is a control unit 18A, 18B is a reservoir

Claims (5)

[Claims] 1. A physical quantity detecting means having a sensor for detecting a physical quantity of a vehicle including at least a steering angle of a steered wheel; a yaw rate detecting means having a sensor for detecting a yaw rate generated in the vehicle; and at least the physical quantity detecting means A target yaw rate is set using the steering angle detected in the step (a), and a yaw moment generated in the vehicle is adjusted in accordance with at least a deviation between the target yaw rate and the yaw rate detected by the yaw rate detection means to adjust the yaw moment in the lateral direction of the vehicle. A control unit for controlling the behavior of the vehicle, the yaw moment being adjusted by the control unit, and the yaw moment by the driver's steering obtained from the steering angle detected by the steering angle detection unit. The yaw rate detecting means and / or the physical quantity detecting means when the direction of A vehicle behavior control device comprising a sensor abnormality detecting means for determining that the vehicle is abnormal. 2. The system according to claim 1, wherein each wheel is provided with a brake wheel cylinder, and the control means adjusts the yaw moment of the vehicle by controlling the fluid pressure of the brake wheel cylinder of each wheel. The detecting means is:
When the control means is increasing the fluid pressure of at least the front right wheel cylinder, one of the yaw rate detection means or the steering angle physical quantity detection means when the driver's steering direction is leftward or The vehicle behavior control device according to claim 1, wherein both sensors determine that there is an abnormality. 3. A sensor abnormality is provided when each wheel is provided with a braking wheel cylinder and the control means adjusts the yaw moment of the vehicle by controlling the fluid pressure of the braking wheel cylinder of each wheel. The detecting means is:
When the control means is increasing the fluid pressure of at least the front left wheel cylinder, the yaw rate detection means and / or the physical quantity detection means are sensors when the driver's steering direction is rightward. The vehicle behavior control device according to claim 1, wherein it is determined that the vehicle is abnormal. 4. When the vehicle has a braking wheel cylinder and the control means adjusts the yaw moment of the vehicle by controlling the fluid pressure of the braking wheel cylinder of each wheel, the sensor abnormality is detected. The detecting means is:
When the control means is increasing the fluid pressure of at least the wheel cylinder of the rear right wheel, one or both of the yaw rate detection means and the physical quantity detection means when the driver's steering direction is the left direction The vehicle behavior control device according to claim 1, wherein the sensor determines that the sensor is abnormal. 5. A sensor abnormality when a braking wheel cylinder is provided for each wheel, and said control means adjusts the yaw moment of the vehicle by controlling a fluid pressure of a braking wheel cylinder for each wheel. The detecting means is:
When the control means is increasing the fluid pressure of at least the wheel cylinder of the rear left wheel, the yaw rate detection means and / or the physical quantity detection means are provided when the driver's steering direction is rightward. The vehicle behavior control device according to claim 1, wherein it is determined that the vehicle is abnormal.