JP3261026B2 - Abnormality detection device for yaw rate sensor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an apparatus for detecting an abnormality in a yaw rate sensor, and more particularly to an apparatus for detecting an abnormality in a yaw rate sensor for detecting a yaw rate of a vehicle.

[0002]

2. Description of the Related Art Conventionally, it has been practiced to detect a yaw rate, a longitudinal acceleration, a lateral acceleration, a steering state, and the like of a vehicle and variably control a lateral distribution and a longitudinal distribution of a braking force of the vehicle. For example, Japanese Unexamined Patent Publication No. 6-24304 discloses that a running state of a vehicle including a steering state, a yaw rate of a vehicle, a lateral acceleration, and a longitudinal acceleration are each detected, and a deviation between a target yaw rate and a detected yaw rate based on the running state is detected. It describes that the target left-right distribution and the target front-rear distribution are calculated based on the acceleration and the control share of the braking force according to the longitudinal acceleration, and the braking force of each wheel is controlled.

[0003]

When the yaw rate sensor becomes abnormal in the conventional braking force control device, there is a possibility that an erroneous yaw rate causes unnecessary braking. In addition, the steering angle, acceleration, and yaw rate maintain a fixed relationship during grip traveling, but if an abnormality occurs in the yaw rate sensor, this relationship is not established, and it is erroneously recognized that the vehicle is in an unstable state such as a vehicle spin. There was a problem.

[0004] The present invention has been made in view of the above point, and the state in which the detected value of the yaw rate sensor is highly likely to have a failure and the state in which the vehicle speed is impossible from the detected value has continued for a threshold value or more. It is an object of the present invention to provide a yaw rate sensor abnormality detection device capable of accurately detecting an abnormality in the yaw rate by determining the abnormality.

[0005]

According to the first aspect of the present invention, as shown in FIG. 1, a first speed determining means M1 for determining whether the vehicle speed is equal to or higher than a first predetermined speed, and a yaw rate sensor Yaw rate determining means M2 for determining a state in which the magnitude of the yaw rate detected in step S1 is larger than a predetermined range.
And detecting the abnormality of the yaw rate sensor when the vehicle speed is equal to or higher than a first predetermined speed and the duration of the state where the magnitude of the yaw rate is larger than a predetermined range is equal to or higher than a first threshold. possess and one of the abnormality detection means M3, before
The vehicle speed at a speed equal to or higher than the first predetermined speed;
The magnitude of the yaw rate when it is larger than the specified range
In each case, vehicle speed x yaw rate size = μ
If the magnitude of the yaw rate exceeds the predetermined range
With respect to the first value so that μ ≦ 1 cannot be achieved.
The predetermined speed was set .

The yaw rate detected by the yaw rate sensor is
The yaw rate determining means determines that the magnitude of the rate is in a state in which the possibility of failure is high, and the yaw rate
When the first speed determination means determines that the vehicle speed is impossible from the magnitude of the vehicle speed, the abnormality detection is performed when the duration of the state becomes equal to or greater than the first threshold value. Can be detected.

According to a second aspect of the present invention, the vehicle speed is set to the second speed.
A second speed determining means for determining a state where the vehicle speed is equal to or lower than a predetermined speed, a yaw rate determining means for determining a state where the magnitude of the yaw rate detected by the yaw rate sensor exceeds a predetermined range, and a second predetermined speed. Below the speed, and
The size of the yaw rate have a second abnormality detection means for detecting an abnormality of the yaw rate sensor when the duration of the high state exceeds a predetermined range is equal to or greater than a second threshold, before
The vehicle speed in a state where the speed is equal to or higher than the second predetermined speed;
The magnitude of the yaw rate when it is larger than the specified range
From each, turning radius x yaw rate size = vehicle speed
The turning radius is within the minimum turning radius of the vehicle.
And the magnitude of the yaw rate exceeding the predetermined range
The second predetermined speed is set to a value that cannot be achieved by
Specified .

The yaw rate detected by the yaw rate sensor is
The yaw rate determining means determines that the magnitude of the rate is in a state in which the possibility of failure is high, and the yaw rate
When the second speed determining means determines that the vehicle speed is impossible from the magnitude of the vehicle speed, the abnormality is detected when the duration of the state becomes equal to or greater than the second threshold value. Can be detected.

According to a third aspect of the present invention, in the abnormality detection device for a yaw rate sensor according to the first aspect, second speed determination means for determining a state in which the vehicle speed is equal to or less than a second predetermined speed, and The speed is equal to or less than a second predetermined speed, and
A second abnormality detecting means for detecting an abnormality of the yaw rate sensor when a duration of a state where the magnitude of the yaw rate exceeds a predetermined range and becomes larger than a second threshold value; When both the means and the second abnormality detecting means detect an abnormality, it is determined that the abnormality of the yaw rate sensor has been determined.

As described above, when both the first and second abnormality detecting means detect the abnormality, the abnormality is determined.
The possibility of erroneously detecting an abnormality in the yaw rate sensor is eliminated.

[0011]

FIG. 2 is a schematic diagram showing an embodiment of the apparatus according to the present invention. In FIG. 1, a yaw rate sensor 10 detects a yaw rate generated in a vehicle and detects an electronic control circuit (EC).
U) 20. The vehicle speed sensor 12 detects the vehicle speed and supplies it to the ECU 20.

The ECU 20 includes a central processing unit (CPU) 22
A read-only memory (ROM) 24 storing a processing program, a random access memory (RAM) 26 used as a work area, an input port circuit 28 including an A / D converter, and an output port circuit 30; It has an EEPROM 32 which is a nonvolatile memory, and these are connected to each other by a bidirectional bus 34. The input port circuit 28 is supplied with detection signals of the yaw rate sensor 10 and the vehicle speed sensor 12, respectively.

FIG. 3 shows a flowchart of the abnormality detection processing executed by the CPU 22. This processing is interrupted at predetermined time intervals. In FIG. 5, in step S10, the vehicle speed detected by the vehicle speed sensor 12 is a predetermined speed (for example, 40 km / h).
It is determined whether or not this is the case. If the vehicle speed is equal to or higher than the predetermined speed, the process proceeds to step S12, and if not, the process proceeds to step S18.

In step S12, the yaw rate sensor 10
Is determined to be equal to or higher than a first predetermined value (for example, 4.25 V). If the detection voltage is equal to or higher than the first predetermined value, the process proceeds to step S14;
Proceed to 16. In step S16, the yaw rate sensor 10
It is determined whether or not the detected voltage is equal to or lower than a second predetermined value (for example, 0.75 V). If the detected voltage is equal to or lower than the second predetermined value, the process proceeds to step S14; otherwise, the process proceeds to step S18. move on.

In step S14, the yaw rate sensor 10
Of the detected voltage, that is, whether or not the difference between the previous and current detected voltages is equal to or less than a predetermined value (for example, 0.0195 V). Is incremented by one, otherwise to step S18. In step S18, the counter C
“1” is cleared to zero, and then the process is terminated.

After incrementing the counter C1 in step S20, the process proceeds to step S22, where it is determined whether or not the value of the counter C1 is equal to or greater than a threshold value corresponding to, for example, 1 second. If the count value is equal to or greater than the threshold value, the process proceeds to step S24. To detect the abnormality of the yaw rate sensor 10 and end the processing. If the count value is less than the threshold value, the process ends. Step S10 described above corresponds to the first speed determination unit M1, steps S12 and S16 correspond to the yaw rate determination unit M2, and steps S18 to S24 correspond to the first abnormality detection unit M3.

Here, the yaw rate sensor 10 has output characteristics shown in FIG . When the yaw rate sensor 10 fails, its output voltage is 0 V or 5 which is the power supply voltage.
There is a high possibility of sticking near V, in which case there is almost no fluctuation in the output voltage. The output voltage of the yaw rate sensor 10 is 0.7 V or less as a value close to 0 V or 5 V, and 4.5 or less.
When V or more is selected, the yaw rate is -70 deg / se
c or less and -70 deg / sec or more. The yaw rate is positive to the left and negative to the right.

In this case, considering a yaw rate of 70 deg / sec or more, there is a relationship of (vehicle speed) × (yaw rate) = road surface μ = lateral acceleration. Since the road surface μ is 1 or less, the lateral acceleration is 1 G or less. , The vehicle speed V is defined as follows.

[0019]

(Equation 1)

That is, in actual running of a vehicle, the speed is 29 km / h.
If it is not below, the yaw rate of 70 deg / sec cannot be taken. The same applies to a yaw rate of -70 deg / sec. In steps S10, S12, and S16 of FIG.
It is determined whether it is not less than c or less than or equal to -70 deg / sec, and further, it is determined in step S14 whether the fluctuation width of the yaw rate output voltage is small and stuck. Then, it is determined in step S22 whether this state continues for 1 second or more, and the abnormality of the yaw rate sensor 10 is detected.

If an abnormality is detected in step S24, for example, an instruction is given to stop the braking force distribution control for performing front-rear distribution and left-right distribution of the braking force. For example, in a special situation where a wheel falls into a groove and runs while being guided by the groove, it is conceivable that the abnormality is detected by the processing in FIG. 3 and the abnormality is detected even if the yaw rate sensor 10 is normal. Of course, there is no problem in stopping the braking force distribution control in such a special situation.

After the abnormality is detected, the abnormality of the yaw rate sensor 10 is determined in consideration of the special situation, in the abnormality determination process described below. FIG.
2 shows a flowchart of an abnormality determination process executed by the CPU. This processing is interrupted at predetermined time intervals. In the figure, in a step S30, it is determined whether or not the vehicle speed detected by the vehicle speed sensor 12 is lower than a predetermined speed (for example, 15 km / h). Here, if the vehicle speed is lower than the predetermined speed, the process proceeds to step S32; otherwise, the process proceeds to step S38.

In step S32, the yaw rate sensor 10
Is determined to be equal to or higher than a first predetermined value (for example, 4.25 V). If the detection voltage is equal to or higher than the first predetermined value, the process proceeds to step S34;
Proceed to 36. In step S36, the yaw rate sensor 10
Is determined to be equal to or lower than a second predetermined value (for example, 0.75 V). If the detected voltage is equal to or lower than the second predetermined value, the process proceeds to step S40; otherwise, the process proceeds to step S38. move on. In step S20, the counter C2 is incremented by one. On the other hand, in step S38, the counter C2 is cleared to zero, and then the processing is terminated.

After incrementing the counter C2 in step S40, the process proceeds to step S42, where it is determined whether or not the value of the counter C2 is equal to or greater than a threshold value corresponding to, for example, 5 seconds. If the count value is equal to or greater than the threshold value, the process proceeds to step S44. Then, the abnormality of the yaw rate sensor 10 is determined, and the process ends. If the count value is less than the threshold value, the process ends. Step S30 corresponds to the second speed determination means, steps S32 and S36 correspond to the yaw rate determination means, and steps S38 to S44 correspond to the second abnormality detection means.

Here, (turn radius) × (yaw rate) =
(Vehicle speed). Therefore, the minimum turning radius 5
m, the vehicle speed V is defined as follows if the yaw rate is 70 deg / sec or more.

[0026]

(Equation 2)

That is, in actual running of the vehicle, the speed is 20 km / h.
Otherwise, the yaw rate of 70 deg / sec cannot be taken. The same applies to a yaw rate of -70 deg / sec. In steps S30, S32, and S36 of FIG. 5, the safety factor is multiplied, and the yaw rate is 70 deg / se at a speed of less than 15 km / h.
It is determined whether or not the speed is equal to or more than c or equal to or less than -70 deg / sec, and whether or not this state continues for 5 seconds or more is determined in step S42, and the abnormality of the yaw rate 10 is determined.

When the abnormality is determined in step S44, for example, a warning lamp is turned on to warn the driver of the abnormality. Note that only the processing in FIG. 5 may be executed without performing the processing in FIG. In this case, an abnormality is detected in step S44, the braking force distribution control is stopped, and the trend lamp is turned on.

[0029]

As described above, the first aspect of the present invention provides
The yaw rate determining means determines that the magnitude of the yaw rate detected by the yaw rate sensor is in a state of a high possibility of failure, and the first speed determining means determines an impossible vehicle speed from the magnitude of the yaw rate. In this case, the abnormality is detected when the duration of the state becomes equal to or greater than the first threshold value, so that the abnormality of the yaw rate sensor can be accurately detected. Further, according to a second aspect of the present invention, the yaw rate determination unit determines that the magnitude of the yaw rate detected by the yaw rate sensor is in a state where the possibility of failure is high, and
The vehicle speed that is impossible from the magnitude of the yaw rate is the second
When the speed is determined by the speed determining means, the abnormality detection is performed when the duration of the state is equal to or greater than the second threshold.
Kill exactly detect the abnormality of the yaw rate sensor.

[0030]

[0031]

[0032]

[0033]

[0034]

[Brief description of the drawings]

FIG. 1 is a principle diagram of the present invention.

FIG. 2 is a schematic configuration diagram of one embodiment of the device of the present invention.

FIG. 3 is a flowchart of an abnormality detection process.

FIG. 4 is an output characteristic diagram of a yaw rate sensor.

FIG. 5 is a flowchart of an abnormality determination process.

[Explanation of symbols]

 Reference Signs List 10 yaw rate sensor 12 vehicle speed sensor 20 ECU 22 CPU 24 ROM 26 RAM 28 input port circuit 30 output port circuit 32 EEPROM 34 bus M1 first speed determination means M2 yaw rate determination means M3 first abnormality detection means

──────────────────────────────────────────────────続 き Continuation of the front page (72) Inventor Toyoharu Katsukura 1-1-1, Showa-cho, Kariya-shi, Aichi Japan Inside Denso Co., Ltd. (56) References JP-A-6-107208 (JP, A) JP-A-7 JP-A-112667 (JP, A) JP-A-3-159877 (JP, A) JP-A-3-90864 (JP, A) JP-A-5-172836 (JP, A) (58) Fields investigated (Int. . ^7, DB name) G01P 15/00 - 15/16 G01C 19/00 - 19/56 G01D 18/00 G01P 21/00 B60T 8/32 B62D 6/00 B62D 7/14

Claims (2)

(57) [Claims] A first speed determination unit that determines a state in which the vehicle speed is equal to or higher than a first predetermined speed; and a yaw rate determination that determines a state in which the magnitude of the yaw rate detected by the yaw rate sensor exceeds a predetermined range. Means for detecting an abnormality in the yaw rate sensor when the vehicle speed is equal to or higher than a first predetermined speed and the duration of a state where the magnitude of the yaw rate is larger than a predetermined range is equal to or higher than a first threshold value. possess a first abnormality detection means, the vehicle speed with the the first predetermined speed or more, and
The magnitude of the yaw rate in a state larger than the predetermined range
Where, vehicle speed x yaw rate size = μ
If the yaw rate exceeds the predetermined range, the
So that the value cannot satisfy μ ≦ 1.
An abnormality detection device for a yaw rate sensor, wherein the predetermined speed is set to 1 . 2. A second speed determining means for determining a state where the vehicle speed is equal to or lower than a second predetermined speed, and a yaw rate determination for determining a state where the magnitude of the yaw rate detected by the yaw rate sensor exceeds a predetermined range and is large. Means for detecting an abnormality of the yaw rate sensor when the vehicle speed is equal to or less than a second predetermined speed and the duration of a state where the magnitude of the yaw rate is larger than a predetermined range is equal to or greater than a second threshold value. possess a second abnormality detection means, the vehicle speed in the second state is the predetermined speed or higher, and
The magnitude of the yaw rate in a state larger than the predetermined range
Turning radius x yaw rate size = vehicle
When the speed is assumed, the turning radius is equal to the minimum turning radius of the vehicle.
And the magnitude of the yaw rate exceeding the predetermined range.
The second predetermined speed is set to a value that cannot be achieved by
An abnormality detection device for a yaw rate sensor, wherein the abnormality is set .