JPH07215193A - Behavioral abnormality detection device of vehicle - Google Patents

Abstract

PURPOSE:To judge both of a spinstate and a drift-out state of a vehicle by furnishing a second judgement means to judge that the vehicle spins at the time when a value of a calculated stability factor differentiated by cross acceleration is smaller than a second specified value. CONSTITUTION:Angle detection signals expressing a handle steering angle thetaf, car velocity V, a yaw rate r and cross acceleration Gy from a steering angle sensor 61, a car velocity sensor 62, a yaw rate sensor 63 and a cross acceleration sensor 64 are inputted. Unrequired high frequency compounds are removed by applying a lowpass-filter treatment to each of these physical quantities thetaf, V, r, Gy, and a stability factor is calculated by carrying out specified computation. When the value of the calculated stability factor differentiated by the cross acceleration is larger than a first specified value, it is judged that a vehicle is in the drift-out state, and when the same differentiated value is smaller than a second specified value, it is judged that the vehicle is in the spin state.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vehicle behavior abnormality detection device for detecting vehicle behavior abnormality, that is, a vehicle drift-out state and a spin state.

[0002]

2. Description of the Related Art Conventionally, an apparatus of this type is disclosed in, for example, Japanese Patent Laid-Open No.
As disclosed in Japanese Patent Laid-Open No. 189214, when the yaw rate and the lateral acceleration of the vehicle are detected and the detected increase rate of the yaw rate is large and the detected decrease rate of the lateral acceleration is small, the vehicle is in a spin state. It has been determined.

[0003]

However, in the above-mentioned conventional device, although the spin state of the vehicle can be detected, the drift-out state of the vehicle cannot be detected. The present invention has been made to address the above problem, and an object thereof is to provide a vehicle behavior abnormality detection device capable of determining both the spin state and the drift-out state of the vehicle.

[0004]

In order to achieve the above object, the structural feature of the present invention is that, when the vehicle spins and drifts out, the stability factor has a specific change characteristic with respect to a change in lateral acceleration. This stability factor is calculated based on the steering angle, the vehicle speed and the yaw rate.
When the value obtained by differentiating the calculated stability factor by lateral acceleration is larger than the first predetermined value, it is determined that the vehicle is in the drift-out state, and when the differentiated value is smaller than the second predetermined value, the vehicle is in the spin state. I decided to determine that there is.

[0005]

In the present invention configured as described above, both the spin state and the drift-out state of the vehicle can be determined, so that an abnormal behavior of the vehicle can be applied to the right and left wheels with appropriate braking force. It is possible to make corrections by appropriately controlling the roll rigidity distribution ratio of the front and rear wheels, so that it becomes possible to improve the maneuverability of the vehicle.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 schematically shows a vehicle braking device to which a vehicle behavior abnormality detecting device according to the present invention is applied, and The electric control device for controlling is shown by a block diagram.

The dual-use braking device is provided with a master cylinder 12 that pumps brake fluid from the first and second ports in response to a depression operation of the brake pedal 11. The first port of the master cylinder 12 has electromagnetic valves 21, 3
When 1 is in the illustrated state, it communicates with the wheel cylinders 22 and 32 for the left and right front wheels via both valves 21 and 31, respectively. The second port of the master cylinder 12 communicates with the left and right rear wheel cylinders 42 and 52 via the proportional valve 13 and the electromagnetic valves 41 and 51, respectively, when the electromagnetic valves 41 and 51 are in the illustrated state.

Further, this vehicle braking device is provided with a hydraulic pump 1.
4, the pump 14 supplies the oil pumped from the reservoir 15 to the high-pressure oil passage L1. An accumulator 16 that stores high-pressure oil is connected to the high-pressure oil passage L1. Between this high-pressure oil passage L1 and the low-pressure oil passage L2 connected to the reservoir 15,
Brake hydraulic pressure control devices 2 for left and right front wheels and left and right rear wheels
0, 30, 40, 50 are connected. The brake hydraulic control device 20 for the left front wheel includes a solenoid valve 2 for increasing pressure, in addition to the solenoid valve 21 and the wheel cylinder 22 described above.
3 and a solenoid valve 24 for decompression. The electromagnetic valve 23 communicates the high-pressure oil passage L1 with the wheel cylinder 22 in the illustrated state when the electromagnetic valve 21 is switched from the illustrated state, and prohibits the communication in the switched state from the illustrated state. When the electromagnetic valve 21 is switched from the illustrated state, the electromagnetic valve 24 has the wheel cylinder 22 in the switched state from the illustrated state.
Is communicated with the low pressure oil passage L2, and the communication is prohibited in the illustrated state.

The brake hydraulic control device 30 for the right front wheel is also
In addition to the electromagnetic valve 31 and the wheel cylinder 32 described above, electromagnetic valves 33 and 34 that function in the same manner as in the case of the brake hydraulic control device 20 for the left front wheel are provided. The brake hydraulic pressure control device 40 for the left rear wheel also includes electromagnetic valves 43 and 44 that function in the same manner as the brake hydraulic pressure control device 20 for the left front wheel, in addition to the electromagnetic valve 41 and the wheel cylinder 42 described above. . The brake hydraulic pressure control device 50 for the right rear wheel also includes the brake hydraulic pressure control device 2 for the left front wheel in addition to the electromagnetic valve 51 and the wheel cylinder 52 described above.
The electromagnetic valves 53 and 54 that function similarly to the case of 0 are provided. The electromagnetic valves described above are maintained in the illustrated state when not energized, and are switched from the illustrated state by energizing.

Next, an electric control device for controlling these electromagnetic valves will be described. The electric control device includes a steering angle sensor (steering angle detecting means) 61, a vehicle speed sensor (vehicle speed detecting means).
62, a yaw rate sensor (yaw rate detecting means) 63,
A lateral acceleration sensor (lateral acceleration detecting means) 64 and hydraulic pressure sensors 65a to 65d are provided. Each of these sensors 61
˜64 detect the steering angle θf, the vehicle speed V, the yaw rate γ, and the lateral acceleration Gy, respectively, and output detection signals respectively indicating the physical quantities θf, V, γ, and Gy that represent the running states of these vehicles. Note that these steering wheel steering angles θf
, Yaw rate γ and lateral acceleration Gy are positive in the left direction and negative in the right direction. Oil pressure sensors 65a-65
d is the braking force Ba to Bd applied to each wheel by measuring the brake hydraulic pressure applied to each of the wheel cylinders 22, 32, 42 and 52, and is a detection that represents the braking force Ba to Bd. Output a signal.

A microcomputer 66 is connected to the steering angle sensor 61, the vehicle speed sensor 62, the yaw rate sensor 63 and the lateral acceleration sensor 64. The microcomputer 66 executes the program corresponding to the flowchart of FIG. 2 to determine the drift-out state and the spin state of the vehicle, and when the determination is the same, the braking device is controlled to automatically correct the abnormal behavior of the vehicle. A control signal for performing the operation is output to the drive control circuit 67. The drive control circuit 67 is the oil pressure sensor 6
5a to 65d are connected to the respective sensors 65a to 65d.
Each solenoid valve 21, 23, 24, 3 in cooperation with 65d
1, 33, 34, 41, 43, 44, 51, 53, 54
By controlling the energization and de-energization of the brake fluid, the supply / discharge of brake fluid to / from the wheel cylinders 22, 32, 42, 52 is controlled.

Next, the operation of the embodiment configured as described above will be described. The microcomputer 66 starts the execution of the program in step 100 of FIG. 2 when the vehicle is started, and repeatedly executes the circulation process including steps 102 to 128. In step 102, the steering angle sensor 61, the vehicle speed sensor 62, the yaw rate sensor 63, and the lateral acceleration sensor 64 are used to input respective detection signals representing the steering wheel steering angle θf, the vehicle speed V, the yaw rate γ, and the lateral acceleration Gy.
At 04, unnecessary high-frequency components are removed by performing low-pass filter processing on each of these physical quantities θf, V, γ, Gy, and at step 106, the operation of the following mathematical expression 1 is executed to calculate the stability factor Kh. .

[0013]

[Equation 1]

It should be noted that N and L in the above equation 1 are a predetermined steering gear ratio and a wheel base, respectively.

Next, the drift-out state or spin state of the vehicle is determined by the comparison processing in steps 108 to 114. At step 108, the stability factor Kh is first differentiated by the lateral acceleration Gy to calculate the differential value dKh / dGy, and at step 108 and step 112, the calculated differential value dKh / dGy and the predetermined values G1 and G2 are calculated. Compare each. Further, in steps 110 and 114, the stability factor Kh is compared with the upper and lower limit values Umax and Lmax, respectively.

These predetermined values G1, G2 and upper and lower limit values Uma
x and Lmax are determined based on the change characteristic of the stability factor Kh with respect to the change of the lateral acceleration Gy (see FIG. 3). The change characteristic of the stability factor Kh will be explained. When the vehicle is in a tendency to drift out or drifts out, the stability factor Kh changes with respect to the lateral acceleration Gy as shown by the solid line in FIG. It has been experimentally confirmed that the vehicle is in the drift-out state when the stability factor Kh is larger than the upper limit value Umax or when the differential value dKh / dGy is larger than the predetermined value G1. When the vehicle tends to spin or spins, the stability factor Kh changes with respect to the lateral acceleration Gy as shown by the broken line in FIG. 3, and the stability factor Kh is smaller than the lower limit value Lmax or a differential value. It has been experimentally confirmed that the vehicle is in the spin state when dKh / dGy is smaller than the predetermined value G2.

That is, if the vehicle is not in the drift-out state or the spin state, it is determined to be "NO" in steps 108 to 114, and the brake release processing is executed in step 116. In this brake release processing, the microcomputer 66 outputs a control signal indicating the brake release to the drive control circuit 67. Drive control circuit 6
7 responds to this control signal by all the electromagnetic valves 21, 2
3,24,31,33,34,41,43,44,5
De-energize 1, 53, 54 to turn the valves 21, 2
3,24,31,33,34,41,43,44,5
1, 53, 54 are kept in the illustrated state. In this state,
When the driver depresses the brake pedal 11 while the vehicle is traveling, the brake fluid is discharged from the first and second ports of the master cylinder 12. The brake fluid discharged from the first port is supplied to the wheel cylinders 22 and 32 via the electromagnetic valves 21 and 31, and the brake fluid discharged from the second port is proportional valve 1.
4 and electromagnetic valves 41, 51 to the wheel cylinders 42, 52. Thus, in this case,
A braking force corresponding to the depression operation of the brake pedal 11 is applied to each wheel, and the vehicle is braked.

On the other hand, the differential value dKh / dGy becomes larger than the predetermined value G1, or the stability factor Kh becomes the upper limit value Um.
If it is larger than ax, step 108 or step 11
At 0, “YES”, that is, it is determined that the vehicle is in the spin state, and the program proceeds to step 118. In step 118, the front wheel and rear wheel distribution values P, Q representing the braking force distribution of the front and rear wheels are determined to predetermined values P1, Q1. In this case, since the vehicle is drifting out and the grip force of the front tires is less than that of the rear tires, the predetermined values P1 and Q1 are in the relationship of P1 <Q1. Next, at step 122, the target braking force B against the yaw motion of the vehicle at the time of drifting out is calculated according to the following mathematical expression 2.

[0019]

[Equation 2]

In the above equation 2, I is the moment of inertia of the vehicle and T is the tread of the vehicle.

After the calculation of the target braking force B, the time differential value dγ / dt of the yaw rate γ is calculated in step 124, and the rotation direction of the vehicle is detected by the positive / negative of the differential value dγ / dt. The vehicle is rotating to the left with respect to the traveling direction, and the time differential value d
If γ / dt is positive, it is determined to be “YES” in step 124 and the program proceeds to step 126. In step 126, the calculated target braking force B is distributed to the front and rear wheels on the right at a ratio of P to Q, and the target braking force B · P / (P + Q), B · Q.
A control signal representing / (P + Q) is output to the drive control circuit 67.

The drive control circuit 67 first detects the electromagnetic valve 2
Energize 1, 31, 41, 51. As a result, the electromagnetic valves 21, 31, 41, 51 are switched from the illustrated state, so that the master cylinder 12 moves to the wheel cylinder 2
The supply passages of the brake fluid to 2, 32, 42 and 52 are closed, and the supply and discharge of the brake fluid to and from the cylinders 22, 32, 42 and 52 are electromagnetic valves 23, 24, 33, 34 and 4.
3,44,53,54. In this state, the drive control circuit 67 causes the calculated target braking forces B · P / (P + Q) and B · Q / (P + Q) of the right and left front wheels and the hydraulic pressure sensor 65.
The electromagnetic valves 33, 3 in the brake hydraulic pressure control devices 30, 50 for the right and left front wheels are compared with the detected braking forces Bb, Bd for the right and left front wheels detected by b and 65d, respectively.
Controlling the energization / de-energization of 4, 53, 54 so that the target braking force B · P / (P + Q) and B · Q / (P + Q) are applied to the right and left wheels, respectively. . That is, the target braking force B ・ P / (P + Q), B ・ Q
If / (P + Q) is larger than the detected braking force Bb, Bd, the solenoid valves 33, 34, 53, 54 are de-energized and the high pressure oil passage L1
Is connected to the wheel cylinders 32, 52 via electromagnetic valves 33, 31, 53, 51, and the cylinders 32, 52 are connected.
Increase the brake hydraulic pressure inside. Target braking force B ・ P / (P +
If Q), B · Q / (P + Q) is smaller than the detected braking force Bb, Bd,
The solenoid valves 33, 34, 53, 54 are energized to move the wheel cylinders 32, 52 to the solenoid valves 31, 34, 51,
Connected to the low pressure oil passage L2 via 54,
The brake hydraulic pressure in 52 is reduced. Also, the target braking force
If B · P / (P + Q) and B · Q / (P + Q) are equal to the detected braking forces Bb and Bd, the electromagnetic valves 33 and 53 are energized and the electromagnetic valves 34 and 54 are deenergized. Wheel cylinder 32,
52 is separated from the high-pressure oil passage L1 and the low-pressure oil passage L2 to maintain the brake hydraulic pressure in the cylinders 32 and 52 as it is.

At the same time, the drive control circuit 67 energizes the electromagnetic valves 23, 24, 43, 44 in the brake hydraulic control devices 20, 40 for the left and right front wheels. This allows
The wheel cylinders 22 and 42 are electromagnetic valves 21 and 24.
By being connected to the low pressure oil passage L2 via 41 and 44, the brake hydraulic pressure is not applied to the cylinders 32 and 52. As a result, the vehicle rotates to the right due to the braking force,
The left rotation of the vehicle in the traveling direction due to the drift-out described above is corrected, and the behavior abnormality of the vehicle is corrected.

On the other hand, if the vehicle is rotating to the right with respect to the traveling direction and the time differential value dγ / dt is negative, the determination at step 124 is "NO" and the program proceeds to step 128. In step 128, control signals representing the target braking forces B · P / (P + Q) and B · Q / (P + Q) of the left and right front wheels are output to the drive control circuit 67. Drive control circuit 67
In the same manner as described above, first, the electromagnetic valves 21, 31, 41,
51 is energized to supply / discharge the brake fluid to / from the cylinders 22, 32, 42, 52 by the electromagnetic valves 23, 24, 3.
It is under the control of 3, 34, 43, 44, 53, 54. After that, the drive control circuit 67 controls the electromagnetic valves 2 in the brake hydraulic pressure control devices 20, 40 for the left and right front wheels as described above.
By controlling the energization and de-energization of 3, 24, 43, 44,
The braking force of the left and right wheels is set to the target braking force B ・ P / (P + Q), B ・ Q /
Control to (P + Q) respectively. At the same time, the drive control circuit 67 energizes the electromagnetic valves 33, 34, 53, 54 in the brake hydraulic pressure control devices 30, 50 for the front and rear wheels on the right side, and the brake hydraulic pressure is applied to the wheel cylinders 32, 52. Prevent it from being granted. As a result, the vehicle is rotated leftward due to the braking force, and the rightward rotation of the vehicle in the traveling direction due to the drift-out described above is corrected, and the vehicle behavior abnormality is corrected.

Further, the differential value dKh / dGy becomes smaller than the predetermined value G2, or the stability factor Kh becomes the lower limit value Lm.
If it is smaller than ax, step 112 or step 11
In "4", "YES", that is, it is determined that the vehicle is in the spin state, and the program proceeds to step 120. In step 120, the front wheel and rear wheel distribution values P and Q representing the front and rear wheel braking force distributions are determined to be predetermined values P2 and Q2. In this case, the vehicle is spinning and the grip force of the rear tires is less than that of the front tires.
2 and Q2 have a relationship of P2> Q2. Next, step 12
In step 2, the target braking force B is calculated by the calculation of the equation 2 as in the above, and in step 124, the rotation direction of the vehicle is determined.

If the vehicle is rotating to the left with respect to the traveling direction and the time differential value dγ / dt is positive, it is determined to be "YES" at step 124, and the drive is performed by the processing at step 126 described above. In cooperation with the control circuit 67, the target braking forces B · P / (P + Q) and B · Q / (P + Q) are applied to the right and left front wheels, respectively.
On the other hand, if the vehicle is rotating to the right with respect to the traveling direction and the time differential value dγ / dt is negative, “N
“O”, and by the processing of step 128 described above, the target braking forces B · P / (P + Q) and B · Q / (P + Q are applied to the left and right front wheels in cooperation with the drive control circuit 67. ) Respectively. As a result, a rotational force opposite to the rotational direction of the vehicle is generated in the vehicle, the left or right rotation of the vehicle due to the spin is corrected, and the abnormal behavior of the vehicle is corrected.

Further, when the above-mentioned drift-out state and spin state of the vehicle are eliminated, steps 108 to 1
It is determined to be “NO” in each of 14 and the above step 1
By the processing of 16, the electromagnetic valves 21, 31, 41, 51 are returned to the illustrated state again in cooperation with the drive control circuit 67. Therefore, the master cylinder 12 and the wheel cylinders 22, 32, 42, 52 communicate with each other, and the brake pedal 1
Each wheel comes to be braked in response to the depression operation of 1.

The feature of the embodiment described above is that step 1
Stability factor K by the processing of 06 (calculation means)
The vehicle is in a drift-out state on the condition that h is calculated and the differential value dKh / dGy obtained by differentiating the stability factor Kh with the lateral acceleration Gy by the determination process (first determining means) of step 108 is larger than the predetermined value G1. Judge that,
Further, the determination process (second determination means) of step 112 determines that the vehicle is in the spin state on condition that the differential value dKh / dGy is smaller than the predetermined value G2. Since the change characteristic of the stability factor Kh with respect to the change of the lateral acceleration Gy represents the spin state and the drift-out state of the vehicle, both the spin state and the drift-out state of the vehicle are accurately determined by the above characteristics.

Another feature of the above embodiment is that it is determined in step 110 that the vehicle is in a drift-out state on condition that the stability factor Kh is larger than a predetermined upper limit value Umax, and 114
It is also possible to determine that the vehicle is in the spin state on the condition that the stability factor Kh is smaller than the predetermined lower limit value Lmax by the determination process of. As a result, both the spin state and the drift-out state of the vehicle can be reliably determined even when the stability factor Kh does not change rapidly with respect to the change in the lateral acceleration Gy. Then, based on the determination of the drift-out state and the spin state of the vehicle as described above, by the processing of steps 120 to 128, the rotation of the vehicle due to the drift-out and spin is forcibly and automatically applied to the left and right front and rear wheels. Since the correction is made by the addition, abnormal behavior of the vehicle is corrected and the maneuverability of the vehicle is improved.

In the above embodiment, the lateral acceleration Gy of the vehicle is detected by using the lateral acceleration sensor 64. However, the lateral acceleration Gy is estimated from the vehicle speed V and the yaw rate γ according to the following equation (3). You may

[0031]

## EQU00003 ## Gy = V.gamma. Further, in the above embodiment, the abnormal behavior of the vehicle is corrected by applying the braking force to the wheels. The behavior abnormality of the vehicle may be corrected by performing the control or the distribution control of the roll rigidity and the braking force control of the above-described embodiment at the same time.

[Brief description of drawings]

FIG. 1 is a diagram schematically showing a vehicle braking device to which a vehicle behavior abnormality detection device of the present invention is applied and an electric control device for the device.

2 is a flowchart of a program executed by the microcomputer of FIG.

FIG. 3 is a graph showing a change characteristic of stability factor with respect to lateral acceleration.

[Explanation of symbols]

11 ... Brake pedal, 12 ... Master cylinder, 20,
30, 40, 50 ... Brake hydraulic pressure control device for each wheel, 2
2, 32, 42, 52 ... Wheel cylinder, 61 ... Rudder angle sensor, 62 ... Vehicle speed sensor, 63 ... Yaw rate sensor,
64 ... Lateral acceleration sensor, 65a-65d ... Oil pressure sensor,
66 ... Microcomputer, 67 ... Drive control circuit.

Claims (1)

[Claims] 1. A steering angle detecting means for detecting a steering angle of a steering wheel, a vehicle speed detecting means for detecting a vehicle speed, a yaw rate detecting means for detecting a yaw rate, a lateral acceleration detecting means for detecting a lateral acceleration, and the detected steering wheel. A calculating means for calculating the stability factor of the vehicle based on the steering angle, the vehicle speed and the yaw rate; and when the value obtained by differentiating the calculated stability factor by the lateral acceleration is larger than a first predetermined value, the vehicle is drifting out. A first determining means for determining; and a second determining means for determining that the vehicle is spinning when a value obtained by differentiating the calculated stability factor by lateral acceleration is smaller than a second predetermined value. Vehicle behavior abnormality detection device.