JP4432885B2 - Yaw rate detection device and vehicle equipped with the same - Google Patents

Description

  The present invention relates to a yaw rate detection device mounted on a vehicle, and particularly to a yaw rate detection device mounted on a vehicle capable of turning at a fixed position, such as a four-wheel independent steering mechanism and a four-wheel independent drive mechanism, and a vehicle including the same.

  Conventionally, yaw rate detection means (yaw rate sensor) for grasping the state of the vehicle is mounted on the vehicle. Such a yaw rate detection means determines that the yaw rate sensor is faulty when the detected value of the yaw rate sensor shows a sudden change exceeding the possible yaw rate change of the vehicle, or two yaw rate sensors. When the difference between detection values of both sensors is larger than a set value, it is determined that the sensor is abnormal. In addition, such a failure detection cannot cope with a failure that reduces the detection value of the yaw rate, and there is a problem that the cost is increased if two yaw rate sensors are used as one set. Therefore, Patent Document 1 discloses a proposal for solving these problems.

  In Patent Document 1, the change rate of the detection value of the yaw rate detection means is compared with the change rate of the estimated yaw rate calculated based on the detection values of the steering angle detection means and the vehicle speed detection means, and the abnormality of the yaw rate detection means is detected. Proposal to judge is made.

JP-A-6-336173

As described above, the abnormality determination device for the yaw rate detection means described in Patent Document 1 attempts to detect an abnormality including an abnormality in which the detection value is small without providing a plurality of yaw rate detection means. .
However, in the abnormality determination device for the yaw rate detection means described in Patent Document 1, there is a difference between the vehicle path expected from the steering angle or the like and the actual vehicle path when, for example, the tire skids during the vehicle turn. May occur, and an accurate estimated yaw rate may not be calculated. As described above, there is room for improvement in the abnormality determination device of the conventional yaw rate detection means.

  On the other hand, in recent years, a vehicle including a four-wheel independent steering mechanism and a four-wheel independent drive mechanism has been proposed as a vehicle capable of changing the direction in a narrow space. Even in such a vehicle, it is required to attach a yaw rate detection means and appropriately detect the yaw rate in order to appropriately perform posture control and the like.

  Therefore, an object of the present invention is to provide a yaw rate detection device that is mounted on a vehicle capable of turning at a fixed position and can maintain high accuracy of yaw rate detection.

  In order to solve such a problem, a yaw rate detection device of the present invention is a yaw rate detection device mounted on a vehicle capable of turning at a fixed position, and includes data acquired by a yaw rate detection unit that acquires a measured yaw rate and a steering angle detection unit. And yaw rate calculation means for calculating an estimated yaw rate using the data acquired by the wheel speed detection means, vehicle state determination means for determining whether the vehicle stays at a fixed position and is in a turning state at the fixed position, An abnormality determination unit that determines an abnormality of the yaw rate detection unit based on a comparison result between the measured yaw rate and the estimated yaw rate when the vehicle state determination unit determines that the vehicle is in a turning state at a certain position; (Claim 1). Further, in such a yaw rate detection device, when the vehicle state determination means determines that the vehicle remains at a certain position, a normal output range in which it can be determined that the measured yaw rate is normal is the estimated yaw rate. And a yaw rate output comparison means for comparing whether or not the yaw rate measured by the yaw rate detection means is within the normal output range. Claim 2).

  The yaw rate detection device of the present invention is premised on being mounted on a vehicle capable of turning at a fixed position, such as including a four-wheel independent steering mechanism and a four-wheel independent drive mechanism. Since the wheels do not skid when the vehicle is turning at a certain position, the accuracy of the estimated yaw rate calculated using the data acquired by the steering angle detection means and the data acquired by the wheel speed detection means is high. it is conceivable that. Therefore, in the present invention, the estimated yaw rate and the measured yaw rate measured by the yaw rate detecting means are measured in anticipation of the timing at which the estimated yaw rate can be calculated with high accuracy when the vehicle is stopped at a certain position or in a turning state at the certain position. And the failure of the yaw rate detection means can be detected. In this specification, the “measured yaw rate” is a yaw rate value obtained directly by the yaw rate detecting means, which is mainly a yaw rate sensor, and the “estimated yaw rate” is data obtained by the steering angle detecting means. And the yaw rate value that can be obtained by calculation using the data acquired by the wheel speed detecting means.

  As described above, since the accuracy of the estimated yaw rate when the vehicle is turning at a certain position is considered to be high, the detection value calibration by the yaw rate detection means is performed by estimating the timing at which the vehicle is turning at the certain position. It is also effective to perform. Therefore, a configuration including a yaw rate calibration unit that performs a calibration process so that the measured yaw rate coincides with the estimated yaw rate when the vehicle state determination unit as described above determines that the vehicle is turning at a certain position. (Claim 3). The yaw rate calibration means may be provided in the yaw rate detection device according to claims 1 and 2.

  If a vehicle capable of turning at a certain position is equipped with the yaw rate detection device as described above, the vehicle of the present invention can be configured (claim 4).

  According to the present invention, a vehicle considered to have a high accuracy of the estimated yaw rate calculated using the data acquired by the steering angle detection means and the data acquired by the wheel speed detection means is stopped at a fixed position, or The abnormality and failure of the yaw rate detection means are detected at the timing when the vehicle is turning, and the calibration measure of the yaw rate detection means can be performed, so that the abnormality and failure of the yaw rate detection means can be accurately determined. Moreover, the accuracy of the yaw rate measured by the yaw rate detection means can be maintained by taking appropriate calibration measures.

  Hereinafter, the best mode for carrying out the present invention will be described in detail with reference to the drawings.

  FIG. 1 is a configuration diagram of a yaw rate detection apparatus 1 according to the present invention. The yaw rate detection device 1 is mounted on a vehicle 30 as shown in FIG. 2 having a four-wheel independent steering mechanism and a four-wheel independent drive mechanism. In the vehicle 30, motors 32 are mounted on wheels 31 arranged at the four corners, and further, a steering device is attached to each of the wheels 31, and it is possible to turn not only forward and backward, right turn and left turn, but also turn at a fixed position. . Further, a steering angle sensor 2 corresponding to a steering angle detection unit and a wheel speed sensor 3 corresponding to a wheel speed detection unit are attached to the wheels 31, respectively. The wheel speed sensor 3 detects not the moving speed of the vehicle 30 but the rotational speed of the wheel 31 itself.

  The yaw rate detection device 1 includes a yaw rate sensor 4 corresponding to a yaw rate detection unit that acquires a measured yaw rate. In addition, a steering angle sensor 2 mounted on each wheel 31, a fixed position turning determination circuit 5 that receives acquired data from the wheel speed sensor 3, and a yaw rate calculation circuit 6 corresponding to a yaw rate calculation means are provided. The wheel speed sensor 3 is connected to a vehicle stop state determination circuit 7. The fixed position turning determination circuit 5 and the vehicle stop state determination circuit 7 correspond to the vehicle state determination means in the present invention. The yaw rate detection device 1 calculates the data from the steering angle sensor 2 and the wheel speed sensor 3 by these circuits to detect the state of the vehicle 30 and turns the vehicle 30 at a fixed position without moving forward or backward. Judgment whether or not it is in the state.

  The yaw rate calculation circuit 6 calculates an estimated yaw rate based on the data of the steering angle sensor 2 and the wheel speed sensor 3. The yaw rate calculation circuit 6 is connected to a fixed position turning determination circuit 5.

  The yaw rate calculation circuit 6 and the vehicle stop state determination circuit 7 are connected to a yaw rate output range calculation circuit 8 corresponding to a yaw rate output range calculation means and a yaw rate calibration circuit 9 corresponding to a yaw rate calibration means.

  The yaw rate output range calculation circuit 8 calculates a range in which the value of the measured yaw rate detected by the yaw rate sensor 4 can be determined to be normal. That is, even if there is a discrepancy between the measured yaw rate value and the estimated yaw rate value, the discrepancy is slight, and the range in which it can be determined that it is operating normally is calculated and set. It is. The yaw rate output range calculation circuit 8 is connected to a yaw rate output comparison circuit 10 corresponding to a yaw rate output comparison means. Whether or not the measured yaw rate is within the normal output range calculated and set by the yaw rate output calculation circuit 8. Compare that. For this reason, the yaw rate output comparison circuit 10 is also connected to the yaw rate sensor 4. The yaw rate output comparison circuit 10 is connected to a yaw rate sensor abnormality determination circuit 11 corresponding to an abnormality determination means, and determines whether the yaw rate sensor 4 is abnormal based on the comparison result in the yaw rate output comparison circuit 10. .

  The yaw rate calibration circuit 9 performs calibration for the yaw rate sensor 4 so that the estimated yaw rate and the measured yaw rate coincide with each other when there is a difference between the measured yaw rate and the estimated yaw rate. Circuit. For this reason, the yaw rate calibration circuit 9 is also connected to the yaw rate sensor 4.

The operation of the yaw rate detection apparatus 1 configured as described above will be described based on the flowchart shown in FIG.
First, in step S <b> 11, the vehicle stop state determination circuit 7 determines whether or not the vehicle is stopped based on data from the wheel speed sensor 3. When it is determined Yes in step S11, that is, when it is determined that the vehicle 30 is stopped and the yaw rate at that time is “0”, the process proceeds to step S12.
The yaw rate calculation circuit 6 always calculates the estimated yaw rate based on the data from the steering angle sensor 2 and the wheel speed sensor 3.

  In step S12, the normal output range in which the yaw rate output range calculation circuit 8 can determine that the yaw rate measured by the yaw rate sensor 4 is normal is calculated. The normal output range is calculated based on the estimated yaw rate. However, when the vehicle 30 is in a stopped state, the estimated yaw rate is “0”, so that an appropriate normal output range can be calculated. FIG. 4 is a graph showing the normal output range. The normal output range takes a predetermined range in the vertical axis direction from the estimated yaw rate “0”, and the range is calculated and determined by setting the sensor output tolerance upper limit and the sensor output tolerance lower limit as shown by the broken line in FIG. .

  After calculating the normal output range in step S12, the process proceeds to step S13, and the yaw rate output comparison circuit 10 determines whether or not the measured yaw rate is within the normal output range. When it is determined No by this determination, that is, when the measured yaw rate exceeds the normal output range, the process proceeds to step S22, and the yaw rate sensor abnormality determination circuit 11 determines that the yaw rate sensor 4 is abnormal. At this time, it may be configured to notify the abnormality of the yaw rate sensor by displaying a warning light or the like.

  On the other hand, when it is determined Yes in step S13, that is, when the output (measured yaw rate) of the yaw rate sensor is within the normal output range as shown by the thick solid line in FIG. Judge that it is normal. Further, at this timing, the yaw rate calibration circuit 9 adjusts the offset amount of the yaw rate sensor 4 so that the yaw rate measured by the yaw rate sensor 4 becomes “0”, and zero point calibration is performed (step S15). That is, in FIG. 5 showing a state of calibrating the yaw rate sensor 4 based on the estimated yaw rate, the zero point indicated by the dotted line and the zero point calibration indicated by the broken line are performed from the state where the gain is not calibrated. , Match zero points. By taking such measures, the detection value of the yaw rate sensor 4 can be maintained with high accuracy.

  After the zero point calibration is performed in step S15, the process proceeds to step S16. In step S16, based on the steering angle and wheel speed, the fixed position turning determination circuit 5 determines whether or not the vehicle 30 is turning on the spot, that is, in a fixed position. When it determines with Yes in step S16, it progresses to step S17. In step S17, the yaw rate calculation circuit 6 calculates the estimated yaw rate based on the data from the steering angle sensor 2 and the wheel speed sensor 3. In step S18, the yaw rate output range calculation circuit 8 calculates a normal output range in which it can be determined that the yaw rate measured by the yaw rate sensor 4 is normal based on the estimated yaw rate.

  After calculating the normal output range in step S18, the process proceeds to step S19, and the yaw rate output comparison circuit 10 determines whether or not the measured yaw rate is within the normal output range. When it is determined No by this determination, that is, when the measured yaw rate exceeds the normal output range, the process proceeds to step S22, and the yaw rate sensor abnormality determination circuit 11 determines that the yaw rate sensor 4 is abnormal. At this time, it may be configured to notify the abnormality of the yaw rate sensor by displaying a warning light or the like.

  On the other hand, when it is determined Yes in step S19, that is, when the output (measured yaw rate) of the yaw rate sensor is within the normal output range as shown by the thick solid line in FIG. Judge that it is normal. Further, at this timing, the yaw rate calibration circuit 9 adjusts the yaw rate sensor 4 so that the gain of the yaw rate measured by the yaw rate sensor 4 matches the estimated yaw rate, and performs gain calibration. That is, in FIG. 5 showing the state of performing the calibration of the yaw rate sensor 4 based on the estimated yaw rate, the zero point calibration and the gain calibration as indicated by the solid line are performed from the state where only the zero point calibration indicated by the broken line is performed, Match the estimated yaw rate value. By taking such measures, the detection value of the yaw rate sensor 4 can be maintained with high accuracy.

  The above-described embodiments are merely examples for carrying out the present invention, and the present invention is not limited thereto. Various modifications of these embodiments are within the scope of the present invention. It is apparent from the above description that various other embodiments are possible within the scope. For example, the steps shown in FIG.

It is a block diagram of the yaw rate detection apparatus of this invention. It is explanatory drawing of the vehicle provided with the four-wheel independent steering mechanism and the four-wheel independent drive mechanism. It is a flowchart explaining an example of operation | movement of a yaw rate detection apparatus. It is the graph which showed the normal output range of the yaw rate sensor. It is a figure showing a mode that a yaw rate sensor is calibrated based on an estimated yaw rate.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Yaw rate detection apparatus 2 Steering angle sensor 3 Wheel speed sensor 4 Yaw rate sensor 5 Fixed position turning determination circuit 6 Yaw rate calculation circuit 7 Vehicle stop state determination circuit 8 Yaw rate output range calculation circuit 9 Yaw rate calibration circuit 10 Yaw rate output comparison circuit 11 Yaw rate sensor abnormality Judgment circuit 30 Vehicle 31 Wheel 32 Motor

Claims (4)

A yaw rate detection device mounted on a vehicle capable of turning at a fixed position,
A yaw rate detection means for obtaining a measured yaw rate;
A yaw rate calculating means for calculating an estimated yaw rate using the data acquired by the steering angle detecting means and the data acquired by the wheel speed detecting means;
Vehicle state determination means for determining whether or not the vehicle stays at a certain position and is in a turning state at the certain position;
An abnormality determination unit that determines an abnormality of the yaw rate detection unit based on a comparison result between the measured yaw rate and the estimated yaw rate when the vehicle state determination unit determines that the vehicle is in a turning state at a certain position;
A yaw rate detection apparatus comprising: The yaw rate detection device according to claim 1, wherein
A yaw rate output range calculation unit that calculates a normal output range based on the estimated yaw rate when the vehicle state determination unit determines that the vehicle stays at a certain position. When,
A yaw rate output comparing means for comparing whether or not the yaw rate measured by the yaw rate detecting means is within the normal output range;
A yaw rate detection apparatus comprising: A yaw rate detection device mounted on a vehicle capable of turning at a fixed position,
A yaw rate detection means for obtaining a measured yaw rate;
A yaw rate calculating means for calculating an estimated yaw rate using the data acquired by the steering angle detecting means and the data acquired by the wheel speed detecting means;
Vehicle state determination means for determining whether the vehicle stays at a certain position and is in a turning state at the certain position;
A yaw rate calibration unit that performs a calibration process so that the measured yaw rate matches the estimated yaw rate when the vehicle state determination unit determines that the vehicle is in a turning state at a certain position;
A yaw rate detection device comprising: A vehicle comprising the yaw rate detection device according to any one of claims 1 to 3.

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