WO2023171255A1

WO2023171255A1 - Yaw rate calibration device

Info

Publication number: WO2023171255A1
Application number: PCT/JP2023/004967
Authority: WO
Inventors: 駿甫佃
Original assignee: 日野自動車株式会社
Priority date: 2022-03-11
Filing date: 2023-02-14
Publication date: 2023-09-14
Also published as: JP2023132591A

Abstract

Provided is a yaw rate calibration device comprising: a lateral position acquisition unit that acquires a lateral position of a vehicle with respect to a target travel position of a travel lane in which the vehicle travels; a driver steering torque acquisition unit that acquires a driver steering torque inputted by a driver; and a zero-point calibration unit that calibrates the zero point of a yaw rate sensor, wherein the zero-point calibration unit calibrates the zero point of the yaw rate sensor on the basis of the lateral position acquired by the lateral position acquisition unit and the driver steering torque acquired by the driver steering torque acquisition unit.

Description

Yaw rate calibration device

One aspect of the present invention relates to a yaw rate calibration device.

Patent Document 1 describes a steering control device that prevents a vehicle from deviating from the road by applying a steering assist torque to a steering means according to the deviation between an actual yaw rate and a reference yaw rate.

Japanese Patent Application Publication No. 08-263794

In the steering control device described in Patent Document 1, the actual yaw rate is detected by a yaw rate sensor. The yaw rate sensor has the property that its zero point drifts due to changes in temperature, the passage of time, and the like. For this reason, conventionally, the zero point of the yaw rate sensor has been calibrated using the value of the yaw rate sensor when the vehicle is stopped as a reference.

However, since it is necessary to stop the vehicle in order to calibrate the zero point, it is not necessarily convenient.

Therefore, one aspect of the present invention is to provide a yaw rate calibration device that can easily calibrate the zero point of a yaw rate sensor.

A yaw rate calibration device according to one aspect of the present invention includes a lateral position acquisition unit that acquires the lateral position of the vehicle with respect to a target travel position of a travel lane in which the vehicle travels, and a driver steering torque that acquires the driver steering torque input by the driver. an acquisition unit, and a zero point calibration unit that calibrates the zero point of the yaw rate sensor, and the zero point calibration unit is based on the lateral position acquired by the lateral position acquisition unit and the driver steering torque acquired by the driver steering torque acquisition unit. calibrate the zero point of the yaw rate sensor.

The relationship between the lateral position of the vehicle and the driver steering torque is different when the zero point of the yaw rate sensor is drifting and when the zero point of the yaw rate sensor is not drifting. Therefore, in this yaw rate calibration device, the zero point of the yaw rate sensor is calibrated based on the lateral position acquired by the lateral position acquisition section and the driver steering torque acquired by the driver steering torque acquisition section. As a result, there is no need to stop the vehicle to calibrate the zero point of the yaw rate sensor, and the zero point of the yaw rate sensor can be automatically calibrated, making it easy to calibrate the zero point of the yaw rate sensor. I can do it.

The vehicle may further include a steering control unit that performs steering control of the vehicle so that the vehicle travels at the target travel position. In this yaw rate calibration device, the steering control section performs steering control of the vehicle so that the vehicle travels at the target travel position, so it is possible to appropriately calibrate the zero point of the yaw rate sensor.

The zero point calibration unit calculates the relationship between the lateral position acquired by the lateral position acquisition unit and the driver steering torque acquired by the driver steering torque acquisition unit, such that the relationship between the lateral position acquired by the lateral position acquisition unit and the driver steering torque acquired by the driver steering torque acquisition unit is determined by the lateral position and driver steering torque when the zero point of the yaw rate sensor is not drifting. If the relationship between the lateral position and driver steering torque differs from the relationship between May be calibrated. When the zero point of the yaw rate sensor is not drifting, the relationship between the lateral position of the vehicle and the driver steering torque is a predetermined relationship. Therefore, in this yaw rate calibration device, if the relationship between the lateral position and the driver steering torque is different from the relationship between the lateral position and the driver steering torque when the zero point of the yaw rate sensor is not drifting, The zero point of the yaw rate sensor is calibrated in such a direction that the relationship between the yaw rate sensor and the yaw rate sensor approaches the relationship between the lateral position and the driver steering torque when the zero point of the yaw rate sensor is not drifting. This allows the zero point of the yaw rate sensor to be properly calibrated.

The zero point calibration unit may calibrate the zero point of the yaw rate sensor in the direction of the driver steering torque when the direction of the lateral position with respect to the target traveling position is different from the direction of the driver steering torque. If the direction of the lateral position with respect to the target driving position differs from the direction of the driver steering torque, the vehicle is traveling at a position offset from the target driving position due to the drift of the zero point of the yaw rate sensor, and the driver is moving at a position offset from the target driving position. It is thought that the vehicle is trying to return to its running position. Therefore, in this yaw rate calibration device, when the direction of the lateral position relative to the target traveling position and the direction of the driver steering torque are different, the zero point of the yaw rate sensor is calibrated in the direction of the driver steering torque, so that the yaw rate sensor can be adjusted appropriately. The zero point can be calibrated.

The zero point calibration unit moves the zero point of the yaw rate sensor in the direction of the driver steering torque when the lateral position exceeds the threshold distance of either the left or right and the driver steering torque exceeds the threshold torque of either the left or right. May be calibrated. If the lateral position exceeds the threshold distance on either the left or right side, and the driver steering torque exceeds the threshold torque on either the left or right side, the vehicle will be offset from the target driving position due to the drift of the zero point of the yaw rate sensor. It is considered that the driver is trying to return the vehicle to the target travel position. Therefore, in this yaw rate calibration device, when the lateral position exceeds the threshold distance of either the left or right, and the driver steering torque exceeds the threshold torque of either the left or right, the zero point of the yaw rate sensor is set to the driver steering torque. By calibrating in the direction of , the zero point of the yaw rate sensor can be appropriately calibrated.

The zero point calibration unit calibrates the zero point of the yaw rate sensor in the direction of the driver steering torque when the lateral position is located in a central region that does not exceed the left and right threshold distance and the driver steering torque exceeds the left and right threshold torque. It's okay. If the lateral position is located in the center region where the left and right threshold distances are not exceeded, and the driver steering torque exceeds the left and right threshold torques, the position where the vehicle is offset from the target driving position due to the drift of the zero point of the yaw rate sensor It is considered that the driver is returning the vehicle to the target travel position because the vehicle is about to travel. Therefore, this yaw rate calibration device sets the zero point of the yaw rate sensor in the direction of the driver steering torque when the lateral position is located in the center region that does not exceed the left and right threshold distances, and when the driver steering torque exceeds the left and right threshold torques. By calibrating the yaw rate sensor, the zero point of the yaw rate sensor can be appropriately calibrated.

The zero point calibration unit moves the zero point of the yaw rate sensor in the direction of the lateral position with respect to the target traveling position when the lateral position exceeds the threshold distance of either the left or right and the driver steering torque does not exceed the left or right threshold torque. May be calibrated. If the lateral position exceeds either the left or right threshold distance, and the driver steering torque does not exceed the left or right threshold torque, the drift of the zero point of the yaw rate sensor will determine the position where the vehicle is offset from the target driving position. Although the vehicle is traveling, it is considered that the driver is not aware that the vehicle is traveling at a position offset from the target travel position. Therefore, in this yaw rate calibration device, when the lateral position exceeds either the left or right threshold distance and the driver steering torque does not exceed the left or right threshold torque, the zero point of the yaw rate sensor is set to the lateral position relative to the target travel position. By calibrating in the direction of , the zero point of the yaw rate sensor can be appropriately calibrated.

The zero point calibration section is based on the average value of the plurality of lateral positions acquired by the lateral position acquisition section at the first set time and the average value of the plurality of driver steering torques acquired at the second set time by the driver steering torque acquisition section. , the zero point of the yaw rate sensor may be calibrated. In this yaw rate calibration device, in order to calibrate the zero point of the yaw rate sensor based on the average value of the lateral position in the first setting time and the average value of the driver steering torque in the second setting time, the lateral position acquisition unit and the driver steering torque acquisition unit are used. Even if a sudden disturbance is input to the part, it is possible to suppress the deterioration of the accuracy of calibration.

The zero point calibration unit may calibrate the zero point of the yaw rate sensor in stages. In this yaw rate calibration device, by calibrating the zero point of the yaw rate sensor in stages, changes in vehicle behavior due to calibration can be made gradual.

The vehicle may further include a curvature acquisition unit that acquires the curvature of the driving lane, and the zero point calibration unit may change a calibration value for calibrating the zero point of the yaw rate sensor according to the curvature acquired by the curvature acquisition unit. In this yaw rate calibration device, the target travel position can be calculated with high accuracy by acquiring the curvature of the travel lane with the curvature acquisition unit. On the other hand, the curvature acquisition unit may incorrectly recognize the curvature due to an error in the installation position in the vehicle. Further, such misrecognition can vary greatly depending on the curvature of the driving lane. Therefore, in this yaw rate calibration device, by changing the calibration value for calibrating the zero point of the yaw rate sensor according to the curvature acquired by the curvature acquisition unit, it is possible to suppress the decrease in calibration accuracy due to misrecognition by the curvature acquisition unit. can.

When the curvature is in a straight line area between the first right threshold curvature and the first left threshold curvature, the zero point calibration section sets the calibration value as the first calibration value, and sets the curvature that is in the straight line area as the first right threshold. When the curvature is exceeded, the calibration value is varied from the first calibration value to the second calibration value, and then when the curvature exceeds the second right threshold curvature, which is closer to zero than the first right threshold curvature, the calibration value is changed to the second calibration value. When the curvature in the straight line area exceeds the second right threshold curvature, the calibration value is changed from the first calibration value to the third calibration value, and then the curvature changes to the first left threshold. The calibration value may be varied from the third calibration value to the first calibration value upon exceeding a second left threshold curvature that is closer to zero than the curvature. In this yaw rate calibration device, by providing a hysteresis characteristic to the relationship between the curvature and the calibration value, it is possible to suppress frequent fluctuations in the calibration value.

The zero point calibration section does not need to calibrate the zero point of the yaw rate sensor until a set time has elapsed after calibrating the zero point of the yaw rate sensor. It takes a certain amount of time after the zero point of the yaw rate sensor is calibrated until the vehicle reaches the target travel position. Therefore, if the zero point of the yaw rate sensor is further calibrated after the zero point of the yaw rate sensor is calibrated and before the vehicle reaches the target travel position, the zero point of the yaw rate sensor may not be properly calibrated. Therefore, in this yaw rate calibration device, since the zero point of the yaw rate sensor is not calibrated until a set time has elapsed after the zero point of the yaw rate sensor is calibrated, the zero point of the yaw rate sensor can be appropriately calibrated.

According to one aspect of the present invention, the zero point of the yaw rate sensor can be easily calibrated.

FIG. 1 is a schematic diagram showing a yaw rate calibration device according to an embodiment. FIG. 2 is a schematic diagram illustrating an example of a situation where a vehicle is traveling in a travel lane. FIG. 3 is a schematic diagram for explaining an example of the direction of driver steering torque input to the steering wheel. FIG. 4 is a schematic diagram showing an example of a situation where a vehicle is traveling on a curved travel lane. FIG. 5 is a table showing an example of the relationship between lateral position and driver steering torque. FIG. 6 is a graph showing an example of the relationship between time and calibration amount. FIG. 7 is a table showing an example of the relationship between the curvature of the driving lane and the calibration value. FIG. 8 is a flowchart showing an example of the processing operation of the yaw rate calibration device.

Hereinafter, embodiments of one aspect of the present invention will be described in detail with reference to the drawings. In the following description, the same or equivalent elements are given the same reference numerals and redundant description will be omitted.

FIG. 1 is a schematic diagram showing a yaw rate calibration device 1 according to an embodiment. As shown in FIG. 1, a yaw rate calibration device 1 according to the present embodiment is a device that is mounted on a vehicle 2 and calibrates the zero point of a yaw rate sensor 3 mounted on the vehicle 2. The yaw rate calibration device 1 is, for example, an electronic control unit (ECU) that includes a CPU (Central Processing Unit), a ROM (Read Only Memory), a RAM (Random Access Memory), and the like. The yaw rate calibration device 1 executes various controls by, for example, loading a program stored in a ROM into a RAM and executing it with a CPU. The yaw rate calibration device 1 may be composed of a single electronic control unit or a plurality of electronic control units.

The yaw rate calibration device 1 includes a steering control section 11, a lateral position acquisition section 12, a driver steering torque acquisition section 13, a curvature acquisition section 14, and a zero point calibration section 15.

FIG. 2 is a schematic diagram showing an example of a situation where the vehicle 2 is traveling in the travel lane TL. As shown in FIGS. 1 and 2, the steering control unit 11 performs steering control of the vehicle 2 so that the vehicle 2 travels at the target travel position TP. The steering control unit 11 performs steering control of the vehicle 2 by driving and controlling a steering actuator (not shown) that applies steering torque to the steering wheel 4 (see FIG. 3). That is, the steering control of the vehicle 2 is performed by driving and controlling the steering actuator. Then, the steering control unit 11 performs steering control of the vehicle 2 so that the vehicle 2 travels in the target travel position TP of the travel lane TL. The target travel position TP is a position in the lane width direction of the travel lane TL, for example, the center of the travel lane TL in the lane width direction. The method of steering control of the vehicle 2 is not particularly limited. For example, the steering control unit 11 performs steering control of the vehicle 2 by applying a signal to the steering wheel 4 based on the difference between the target yaw rate necessary for the vehicle 2 to travel at a predetermined position in the travel lane TL and the current yaw rate of the vehicle 2. Alternatively, the steering actuator may be driven and controlled by calculating the steering torque that corresponds to the calculated steering torque.

The lateral position acquisition unit 12 acquires the lateral position LP of the vehicle 2 with respect to the target travel position TP of the travel lane TL in which the vehicle 2 travels. The lateral position LP of the vehicle 2 is the position of the vehicle 2 relative to the target travel position TP in the lane width direction of the travel lane TL. The position of the vehicle 2 can be, for example, the center of gravity of the vehicle 2. For example, the lateral position acquisition unit 12 extracts the marking line (white line) of the driving lane TL from an image captured by a camera (not shown), and determines the position of the vehicle 2 based on the positional relationship between the extracted marking line and the vehicle 2. Get the position of. The lateral position acquisition unit 12 also acquires a target travel position TP, which serves as a reference for steering control of the vehicle 2, from the steering control unit 11. Then, the lateral position acquisition unit 12 acquires the lateral position LP of the vehicle 2 based on the position of the vehicle 2 and the target travel position TP. For example, the lateral position acquisition unit 12 sets the lateral position LP on the right side to be a minus value with respect to the target traveling position TP, and sets the lateral position LP on the left side as a positive value with respect to the target traveling position TP.

The driver steering torque acquisition unit 13 acquires the driver steering torque input by the driver. A steering torque that is a combination of the control steering torque input by the steering actuator and the driver steering torque input to the steering wheel 4 by the driver to steer the vehicle 2 is input to the steering wheel 4 . The controlled steering torque is a torque that is input to the steering wheel 4 by a steering actuator whose drive is controlled by the steering control section 11 . The control steering torque can be calculated from the control value of the steering control section 11. The steering torque can be calculated by a torque sensor connected directly or indirectly to the steering wheel 4. Therefore, the driver steering torque acquisition unit 13 acquires the torque obtained by subtracting the control steering torque from the steering torque as the driver steering torque. In other words, the driver steering torque acquired by the driver steering torque acquisition unit 13 is not the actual torque that the driver inputs to the steering wheel 4 to steer the vehicle 2, but the actual torque that the driver inputs to the steering wheel 4 to steer the vehicle 2. is the estimated torque (estimated value of driver steering torque). However, if it is possible to directly obtain the driver steering torque, the driver steering torque may be directly obtained instead of the estimated value. FIG. 3 is a schematic diagram for explaining an example of the direction of driver steering torque input to the steering wheel 4. As shown in FIG. As shown in FIG. 3, the driver steering torque acquisition unit 13 sets, for example, the driver steering torque in the right steering direction (right turning direction) as a positive value, and the driver steering torque in the left steering direction (left turning direction) as a negative value. .

As shown in FIGS. 1 and 2, the curvature acquisition unit 14 acquires the curvature of the travel lane TL. The curvature acquisition unit 14, for example, extracts the marking line (white line) of the driving lane TL from the image captured by the camera, calculates a reference line passing through the center of the driving lane TL in the lane width direction from the extracted marking line, The curvature of the travel lane TL is obtained by calculating the curvature of the calculated reference line. The curvature of the travel lane TL is used, for example, to calculate a target yaw rate that is a reference for steering control of the vehicle 2 by the steering control unit 11. For example, the curvature acquisition unit 14 sets the curvature of the right-curving driving lane TL to a minus value, and sets the curvature of the left-curving driving lane TL to a positive value.

The zero point calibration unit 15 calibrates the zero point of the yaw rate sensor 3. The yaw rate sensor 3 is a sensor that detects the yaw rate of the vehicle 2. The yaw rate detected by the yaw rate sensor 3 is used, for example, for steering control by the steering control unit 11. The zero point calibration unit 15 calibrates the zero point of the yaw rate sensor 3 based on the lateral position LP acquired by the lateral position acquisition unit 12 and the driver steering torque acquired by the driver steering torque acquisition unit 13.

FIG. 4 is a schematic diagram showing an example of a situation where the vehicle 2 is traveling in a curved travel lane TL. As shown in FIG. 4, when the steering control unit 11 performs steering control of the vehicle 2 so that the vehicle 2 travels at the target travel position TP, if the zero point of the yaw rate sensor 3 does not drift, the vehicle 2 The vehicle travels along the target travel position TP. However, if the zero point of the yaw rate sensor 3 is drifting, the vehicle 2 travels at a position offset from the target travel position TP. For example, if the zero point of the yaw rate sensor 3 is drifting toward the left turning side, the vehicle 2 will travel at a position to the left of the target travel position TP, and the zero point of the yaw rate sensor 3 will drift toward the right turning side. , the vehicle 2 travels at a position to the right of the target travel position TP.

The zero point calibration unit 15 determines that the relationship between the lateral position LP acquired by the lateral position acquisition unit 12 and the driver steering torque acquired by the driver steering torque acquisition unit 13 is lateral when the zero point of the yaw rate sensor 3 is not drifting. When the relationship between the position LP and the driver steering torque is different, the relationship between the lateral position LP and the driver steering torque approaches the relationship between the lateral position LP and the driver steering torque when the zero point of the yaw rate sensor 3 is not drifting. calibrate the zero point of the yaw rate sensor 3 in the direction.

For example, if the direction of the lateral position LP with respect to the target travel position TP is different from the direction of the driver steering torque, the vehicle 2 may travel at a position offset from the target travel position TP due to the drift of the zero point of the yaw rate sensor 3. It is considered that the driver is trying to return the vehicle to the target travel position TP. Therefore, if the direction of the lateral position LP with respect to the target traveling position TP is different from the direction of the driver steering torque, the zero point calibration unit 15 calibrates the zero point of the yaw rate sensor 3 in the direction of the driver steering torque. The zero point calibration direction of this yaw rate sensor 3 is the turning direction corresponding to the direction of driver steering torque. For example, when the driver steering torque is in the right steering direction, the zero point of the yaw rate sensor 3 is calibrated to the right turning direction.

Further, for example, if the lateral position LP exceeds the threshold distance of either the left or right, and the driver steering torque exceeds the threshold torque of the other left or right, the drift of the zero point of the yaw rate sensor 3 causes the vehicle 2 to It is considered that the vehicle is traveling at a position offset from the target traveling position TP, and the driver is trying to return the vehicle to the target traveling position TP. Therefore, the zero point calibration unit 15 sets the zero point of the yaw rate sensor 3 to the driver when the lateral position LP exceeds the threshold distance of either the left or right and the driver steering torque exceeds the other threshold torque of the left or right. Calibrate in the direction of steering torque. The zero point calibration direction of this yaw rate sensor 3 is the turning direction corresponding to the direction of driver steering torque. For example, when the driver steering torque is in the right steering direction, the zero point of the yaw rate sensor 3 is calibrated to the right turning direction.

Further, for example, if the lateral position LP exceeds the threshold distance of either the left or right, and the driver steering torque exceeds the threshold torque of the other left or right, the drift of the zero point of the yaw rate sensor 3 causes the vehicle 2 to It is considered that the vehicle is traveling at a position offset from the target traveling position TP, and the driver is trying to return the vehicle to the target traveling position TP. Therefore, if the lateral position LP is located in the central region that does not exceed the left and right threshold distances, and the driver steering torque exceeds the left and right threshold torques, the zero point calibration unit 15 adjusts the zero point of the yaw rate sensor 3 to the driver steering torque. Calibrate in the direction of The zero point calibration direction of this yaw rate sensor 3 is the turning direction corresponding to the direction of driver steering torque. For example, when the driver steering torque is in the right steering direction, the zero point of the yaw rate sensor 3 is calibrated to the right turning direction.

Further, for example, if the lateral position LP exceeds the threshold distance of either the left or right, and the driver steering torque does not exceed the left or right threshold torque, the zero point of the yaw rate sensor 3 drifts and the vehicle 2 is moved to the target traveling position. Although the vehicle is traveling at a position offset from the target travel position TP, it is considered that the driver is not aware that the vehicle is traveling at a position offset from the target travel position TP. Therefore, if the lateral position LP exceeds either the left or right threshold distance and the driver steering torque does not exceed the left or right threshold torque, the zero point calibration unit 15 changes the zero point of the yaw rate sensor 3 to the target travel position TP. Calibrate in the direction of the lateral position LP with respect to. The calibration direction of the zero point of this yaw rate sensor 3 is the turning direction corresponding to the lateral position LP with respect to the target traveling position TP. For example, when the lateral position LP is located to the right of the target travel position TP, the zero point of the yaw rate sensor 3 is calibrated in the right turning direction.

FIG. 5 is a table showing an example of the relationship between lateral position LP and driver steering torque. In FIG. 5, the lateral position LP is divided into three regions: a left region, a center region, and a right region. The left area is an area where the lateral position LP exceeds the left threshold distance, that is, an area where the lateral position LP is located to the left of the left threshold distance. The central area is an area where the lateral position LP does not exceed the left and right threshold distances. The right area is an area where the lateral position LP exceeds the right threshold distance, that is, an area where the lateral position LP is located to the right of the right threshold distance. The left threshold distance is a predetermined distance located to the left of the target travel position TP, and can be set to +0.2 m, for example. The right threshold distance is a predetermined distance located to the right of the target travel position TP, and can be set to -0.2 m, for example.

Furthermore, in FIG. 5, the driver steering torque is divided into three regions: a left steering region, a no-steering region, and a right steering region. The left steering region is a region where the driver steering torque exceeds the left threshold torque, that is, a region where the driver steering torque is larger in the left steering direction than the left threshold torque. The no-steering region is a region in which the driver steering torque does not exceed the left and right threshold torques. The right steering region is a region where the driver steering torque exceeds the right threshold torque, that is, a region where the driver steering torque is larger in the right steering direction than the right threshold torque. The left threshold torque is a torque that causes the driver steering torque to be in the left steering direction, and can be set to -0.2 Nm, for example. The right threshold torque is a torque that causes the driver steering torque to be in the right steering direction, and can be set to +0.2 Nm, for example.

As shown in FIG. 5, when the zero point of the yaw rate sensor 3 is not drifting, the relationship between the lateral position LP and the target traveling position TP is as indicated by the cross in FIG. The relationship is one of the following: "region", "center region - non-steering region", and "right side region - right steering region".

When the relationship is "left side area - left steering area," the driver wants to drive the vehicle 2 to the left of the target driving position TP, so the driver inputs driver steering torque in the left steering direction to the steering wheel 4. This is considered to be the situation. When the relationship is "center area - no-steering area", the driver is not inputting driver steering torque to the steering wheel 4 because the driver wants to drive the vehicle 2 at or near the target driving position TP, or It is thought that the situation is such that almost no input is made. When the relationship is "right side area - right steering area", the driver wants to drive the vehicle 2 to the right side of the target driving position TP, so the driver inputs driver steering torque in the right steering direction to the steering wheel 4. This is considered to be the situation.

On the other hand, when the zero point of the yaw rate sensor 3 is drifting, the relationship between the lateral position LP and the target traveling position TP is as indicated by the circle in FIG. The relationship is one of the following: ``area - right steering area'', ``center area - left steering area'', ``center area - right steering area'', ``right area - non-steering area'', and ``left area - non-steering area''. .

When the relationship is "right side area - left steering area," the vehicle 2 was traveling on the right side far more than the target driving position TP, so the driver inputs driver steering torque in the left steering direction to the steering wheel 4, and the vehicle It is considered that the current situation is that the vehicle is trying to return the vehicle to the target travel position TP. When the relationship is "left side area - right steering area," the vehicle 2 was traveling on the left side of the target driving position TP, so the driver inputs driver steering torque in the right steering direction to the steering wheel 4, and the vehicle It is considered that the current situation is that the vehicle is trying to return the vehicle to the target travel position TP.

When the relationship is "center area - left steering area", the vehicle 2 tries to run on the right side of the target driving position TP, so the driver inputs driver steering torque in the left steering direction to the steering wheel 4, and the vehicle It is considered that the current situation is that the vehicle is trying to return the vehicle to the target travel position TP. When the relationship is "center area - right steering area", the vehicle 2 tries to travel to the left of the target travel position TP, so the driver inputs driver steering torque in the right steering direction to the steering wheel 4, and the vehicle It is considered that the current situation is that the vehicle is trying to return the vehicle to the target travel position TP.

When the relationship is "right side area - no-steering area", the vehicle 2 is traveling on the right side of the target traveling position TP, but the driver is not aware that the vehicle 2 is traveling on the right side of the target traveling position TP. This is considered to be a situation where the driver is not aware of this, or because the driver wants to drive the vehicle 2 to the right of the target driving position TP, the driver is not inputting driver steering torque to the steering wheel 4, or is inputting almost no driver steering torque. It will be done. When the relationship is "left side area - no-steering area", the driver is unaware that the vehicle 2 is traveling on the left side of the target traveling position TP, or the vehicle 2 is traveling on the left side of the target traveling position TP. Although the vehicle is traveling on the left side, the driver wants the vehicle 2 to travel to the left of the target travel position TP, so it is assumed that the driver is not inputting driver steering torque to the steering wheel 4 or is inputting almost no driver steering torque. It will be done.

Therefore, the zero point calibration unit 15 determines that the relationship between the lateral position LP and the target travel position TP is "right side area - left steering area" and "left side area - right steering area" as indicated by the circle in FIG. , "center area - left steering area", "center area - right steering area", "right side area - no steering area", and "left area - no steering area", the yaw rate sensor 3 Calibrate the zero point of

If the relationship between the lateral position LP and the target travel position TP is "right side region - left steering region", the zero point of the yaw rate sensor 3 is calibrated to the left turning direction corresponding to the direction of the driver steering torque. When the relationship between the lateral position LP and the target travel position TP is "left side area - right steering area", the zero point of the yaw rate sensor 3 is calibrated to the right turning direction corresponding to the direction of the driver steering torque.

If the relationship between the lateral position LP and the target travel position TP is "center region - left steering region", the zero point of the yaw rate sensor 3 is calibrated to the left turning direction corresponding to the direction of the driver steering torque. When the relationship between the lateral position LP and the target travel position TP is "center region - right steering region", the zero point of the yaw rate sensor 3 is calibrated to the right turning direction corresponding to the direction of the driver steering torque.

When the relationship between the lateral position LP and the target travel position TP is "right side area - no steering area", the zero point of the yaw rate sensor 3 is set in the right turning direction corresponding to the direction of the lateral position LP with respect to the target travel position TP. Calibrate. When the relationship between the lateral position LP and the target travel position TP is "left side area - no steering area", the zero point of the yaw rate sensor 3 is calibrated to the left turning direction corresponding to the direction of the lateral position LP with respect to the target travel position TP. do.

The zero point calibration unit 15 calibrates the zero point of the yaw rate sensor based on one lateral position LP acquired immediately before by the lateral position acquisition unit 12 and one driver steering torque acquired immediately before by the driver steering torque acquisition unit 13. However, the average value of the plurality of lateral positions LP acquired by the lateral position acquisition unit 12 during the first set time and the average value of the multiple driver steering torques acquired by the driver steering torque acquisition unit 13 during the second set time It is preferable to calibrate the zero point of the yaw rate sensor based on this. That is, the zero point calibration unit 15 sets the average value of the plurality of lateral positions LP acquired by the lateral position acquisition unit 12 during the first set time as the lateral position LP acquired by the lateral position acquisition unit 12, and also It is preferable to calibrate the zero point of the yaw rate sensor 3 by using the average value of the plurality of driver steering torques acquired by the acquisition unit 13 during the second set time as the driver steering torque acquired by the driver steering torque acquisition unit 13. The first setting time and the second setting time are not particularly limited, but are preferably the first setting time and the second setting time immediately before the zero point calibration section 15 calibrates the zero point of the yaw rate sensor. . . Further, the first set time and the second set time may be the same or different. For example, the first set time and the second set time can each be 10 seconds.

FIG. 6 is a graph showing an example of the relationship between time and calibration amount. The calibration amount is an integrated value obtained by integrating the calibration values obtained by calibrating the zero point of the yaw rate sensor 3 from the start of the calibration of the zero point of the yaw rate sensor 3 to the end of the calibration of the zero point of the yaw rate sensor 3. When calibrating the zero point of the yaw rate sensor 3, the zero point calibration unit 15 may calibrate the zero point of the yaw rate sensor 3 all at once, but it is preferable to calibrate the zero point of the yaw rate sensor 3 in stages as shown in FIG. That is, it is preferable that the zero point calibration section 15 calibrates the zero point of the yaw rate sensor 3 for each predetermined calibration value.

The calibration value for calibrating the zero point of the yaw rate sensor 3 in stages is not particularly limited, and may be a fixed value or a variable value. When the calibration value is a fixed value, the fixed value can be, for example, 0.002 [rad/s]. When the calibration value is a variable value, the calibration value may be varied depending on, for example, the curvature of the travel lane TL. That is, the zero point calibration unit 15 may calibrate the zero point of the yaw rate sensor 3 using a calibration value that varies depending on the curvature of the travel lane TL and the like. The curvature of the travel lane TL can be acquired by the curvature acquisition unit 14.

When varying the calibration value according to the curvature of the travel lane TL, the curvature and the calibration value may correspond one-to-one, but as shown in FIG. 7, a hysteresis characteristic may be provided. FIG. 7 is a table showing an example of the relationship between the curvature of the travel lane TL and the calibration value. In FIG. 7, when the curvature of the driving lane TL is in a straight line region between the first right threshold curvature and the first left threshold curvature, the calibration value is set as the first calibration value. When the curvature of the driving lane TL in the straight line region exceeds the first right threshold curvature, the calibration value is changed from the first calibration value to the second calibration value, and then the curvature of the driving lane TL exceeds the first right threshold curvature. When a second right threshold curvature, which is closer to zero than the curvature, is exceeded, the calibration value is varied from the second calibration value to the first calibration value. Further, when the curvature of the driving lane TL in the straight region exceeds the first left threshold curvature, the calibration value is changed from the first calibration value to the third calibration value, and then the curvature of the driving lane TL exceeds the first left threshold curvature. When a second left threshold curvature, which is closer to zero than the curvature, is exceeded, the calibration value is changed from the third calibration value to the first calibration value. The first right threshold curvature, the second right threshold curvature, the first left threshold curvature, and the second left threshold curvature are not particularly limited. Moreover, the first calibration value, the second calibration value, and the third calibration value are not particularly limited.

Further, the zero point calibration unit 15 may continuously calibrate the zero point of the yaw rate sensor 3, but after calibrating the zero point of the yaw rate sensor 3 until the vehicle 2 reaches the target traveling position TP, It will take some time. Therefore, as shown in FIG. 6, it is preferable not to calibrate the zero point of the yaw rate sensor 3 until a set time has elapsed after the zero point of the yaw rate sensor 3 is calibrated. That is, the zero point calibration unit 15 calibrates the zero point of the yaw rate sensor 3 at set time intervals. The set time is not particularly limited, and can be set to, for example, 10 seconds.

Next, an example of the processing operation of the yaw rate calibration device 1 will be described with reference to FIG. 8. FIG. 8 is a flowchart showing an example of the processing operation of the yaw rate calibration device 1.

As shown in FIG. 8, the yaw rate calibration device 1 acquires the lateral position LP and driver steering torque (step S1). In step S1, the curvature of the travel lane TL may also be acquired.

Next, the yaw rate calibration device 1 determines whether it is necessary to calibrate the zero point of the yaw rate sensor 3 (step S2). In step S2, the relationship between the lateral position LP and the driver steering torque is determined by referring to the table in FIG. If the relationship is different from the above, it is determined that the zero point of the yaw rate sensor 3 needs to be calibrated. If it is determined that there is no need to calibrate the zero point of the yaw rate sensor 3 (step S2: NO), the yaw rate calibration device 1 once ends the process and repeats the process from step S1 again after the set time has elapsed.

On the other hand, if it is determined that the zero point of the yaw rate sensor 3 needs to be calibrated (step S2: YES), the yaw rate calibration device 1 adjusts the yaw rate sensor 3 based on the lateral position LP and driver steering torque acquired in step S1. The zero point is calibrated (step S3). In step S3, the relationship between the lateral position LP and the driver steering torque is determined by referring to the table in FIG. The zero point of the yaw rate sensor 3 is calibrated in a direction that approaches the relationship. Thereafter, the yaw rate calibration device 1 once ends the process, and after the set time has elapsed, repeats the process again from step S1.

As explained above, in the yaw rate calibration device 1 according to the present embodiment, the lateral position of the vehicle and the driver's steering are adjusted depending on when the zero point of the yaw rate sensor is drifting and when the zero point of the yaw rate sensor is not drifting. Since the relationship with torque is different, the zero point of the yaw rate sensor 3 is calibrated based on the lateral position LP acquired by the lateral position acquisition unit 12 and the driver steering torque acquired by the driver steering torque acquisition unit 13. As a result, there is no need to stop the vehicle 2 to calibrate the zero point of the yaw rate sensor 3, and the zero point of the yaw rate sensor 3 can be automatically calibrated. can be calibrated.

Furthermore, in this yaw rate calibration device 1, the steering control unit 11 performs steering control of the vehicle 2 so that the vehicle 2 travels at the target travel position TP, so that the zero point of the yaw rate sensor 3 can be appropriately calibrated. .

Furthermore, in this yaw rate calibration device 1, if the relationship between the lateral position and the driver steering torque is different from the relationship between the lateral position LP and the driver steering torque when the zero point of the yaw rate sensor 3 is not drifting, the lateral position LP The zero point of the yaw rate sensor 3 is calibrated so that the relationship between the lateral position LP and the driver steering torque approaches the relationship between the lateral position LP and the driver steering torque when the zero point of the yaw rate sensor 3 is not drifting. Thereby, the zero point of the yaw rate sensor 3 can be appropriately calibrated.

Furthermore, in this yaw rate calibration device 1, when the direction of the lateral position LP with respect to the target traveling position TP is different from the direction of the driver steering torque, the zero point of the yaw rate sensor 3 is calibrated in the direction of the driver steering torque, so that the yaw rate sensor 3 can be properly adjusted. The zero point of the yaw rate sensor 3 can be calibrated.

In addition, in this yaw rate calibration device 1, when the lateral position LP exceeds the threshold distance of either the left or right, and the driver steering torque exceeds the threshold torque of either the left or right, the zero point of the yaw rate sensor 3 is adjusted. By calibrating in the direction of the driver steering torque, the zero point of the yaw rate sensor 3 can be appropriately calibrated.

Furthermore, in this yaw rate calibration device 1, when the lateral position LP is located in the central region that does not exceed the left and right threshold distances, and the driver steering torque exceeds the left and right threshold torques, the zero point of the yaw rate sensor 3 is set to the driver's steering. By calibrating in the torque direction, the zero point of the yaw rate sensor 3 can be appropriately calibrated.

In addition, in this yaw rate calibration device 1, when the lateral position LP exceeds the threshold distance of either the left or right and the driver steering torque does not exceed the left or right threshold torque, the zero point of the yaw rate sensor 3 is set to the target traveling position. By calibrating in the direction of the lateral position LP with respect to TP, the zero point of the yaw rate sensor 3 can be appropriately calibrated.

In addition, in this yaw rate calibration device 1, in order to calibrate the zero point of the yaw rate sensor 3 based on the average value of the lateral position LP in the first set time and the average value of the driver steering torque in the second set time, Even if a sudden disturbance is input to the driver steering torque acquisition section 12 and the driver steering torque acquisition section 13, it is possible to suppress a decrease in the accuracy of calibration.

Furthermore, in this yaw rate calibration device 1, by calibrating the zero point of the yaw rate sensor 3 in stages, changes in the behavior of the vehicle 2 due to calibration can be made gradual.

Furthermore, in this yaw rate calibration device 1, the target travel position TP can be calculated with high accuracy by acquiring the curvature of the travel lane TL using the curvature acquisition unit 14. On the other hand, the curvature acquisition unit 14 may misrecognize the curvature due to an error in the installation position in the vehicle 2 or the like. Furthermore, such misrecognition can vary greatly depending on the curvature of the travel lane TL. Therefore, in this yaw rate calibration device 1, by changing the calibration value for calibrating the zero point of the yaw rate sensor 3 according to the curvature acquired by the curvature acquisition unit 14, the decrease in calibration accuracy due to misrecognition by the curvature acquisition unit 14 is prevented. Can be suppressed.

Furthermore, in this yaw rate calibration device 1, by providing a hysteresis characteristic to the relationship between the curvature and the calibration value, it is possible to suppress frequent fluctuations in the calibration value.

Furthermore, in this yaw rate calibration device 1, the zero point of the yaw rate sensor 3 is not calibrated until a set time has elapsed after the zero point of the yaw rate sensor 3 is calibrated, so the zero point of the yaw rate sensor 3 must be appropriately calibrated. I can do it.

Although the embodiment of one aspect of the present invention has been described above, one aspect of the present invention is not limited to the above embodiment, and may be modified or modified without changing the gist of each claim. May be applied to things.

DESCRIPTION OF SYMBOLS 1... Yaw rate calibration device, 2... Vehicle, 3... Yaw rate sensor, 4... Steering, 11... Steering control section, 12... Lateral position acquisition section, 13... Driver steering torque acquisition section, 14... Curvature acquisition section, 15... Zero point Calibration section, LP...Lateral position, TL...Travel lane, TP...Target travel position.

Claims

a lateral position acquisition unit that acquires a lateral position of the vehicle with respect to a target travel position of a travel lane in which the vehicle is traveling;
a driver steering torque acquisition unit that acquires the driver steering torque input by the driver;
A zero point calibration section that calibrates the zero point of the yaw rate sensor,
The zero point calibration unit calibrates the zero point of the yaw rate sensor based on the lateral position acquired by the lateral position acquisition unit and the driver steering torque acquired by the driver steering torque acquisition unit.
Yaw rate calibration device.
further comprising a steering control unit that performs steering control of the vehicle so that the vehicle travels at a target travel position;
The yaw rate calibration device according to claim 1.
The zero point calibration unit calculates a relationship between the lateral position acquired by the lateral position acquisition unit and the driver steering torque acquired by the driver steering torque acquisition unit when the zero point of the yaw rate sensor does not drift. If the relationship between the lateral position and the driver steering torque is different from the relationship between the lateral position and the driver steering torque, the relationship between the lateral position and the driver steering torque is different from the relationship between the lateral position and the driver steering when the zero point of the yaw rate sensor is not drifting. calibrating the zero point of the yaw rate sensor in a direction that approaches a relationship with torque;
The yaw rate calibration device according to claim 1 or 2.
The zero point calibration unit calibrates the zero point of the yaw rate sensor in the direction of the driver steering torque when the direction of the lateral position with respect to the target traveling position is different from the direction of the driver steering torque.
The yaw rate calibration device according to any one of claims 1 to 3.
The zero point calibration unit adjusts the zero point of the yaw rate sensor to Calibrate in the direction of driver steering torque,
The yaw rate calibration device according to any one of claims 1 to 4.
The zero point calibration unit adjusts the zero point of the yaw rate sensor to the zero point of the yaw rate sensor when the lateral position is located in a central region that does not exceed a left and right threshold distance, and the driver steering torque exceeds a left and right threshold torque. Calibrate in the direction of torque,
The yaw rate calibration device according to any one of claims 1 to 5.
The zero point calibration unit adjusts the zero point of the yaw rate sensor to the target travel position when the lateral position exceeds a threshold distance of either the left or right and the driver steering torque does not exceed the left or right threshold torque. calibrating in the direction of said lateral position relative to;
A yaw rate calibration device according to any one of claims 1 to 6.
The zero point calibration unit calculates an average value of the plurality of lateral positions acquired by the lateral position acquisition unit at a first set time and an average value of the plurality of driver steering torques acquired by the driver steering torque acquisition unit at a second set time. calibrating the zero point of the yaw rate sensor based on an average value;
A yaw rate calibration device according to any one of claims 1 to 7.
The zero point calibration unit calibrates the zero point of the yaw rate sensor in stages.
A yaw rate calibration device according to any one of claims 1 to 8.
Further comprising a curvature acquisition unit that acquires the curvature of the driving lane,
The zero point calibration unit changes a calibration value for calibrating the zero point of the yaw rate sensor according to the curvature acquired by the curvature acquisition unit.
A yaw rate calibration device according to any one of claims 1 to 9.
The zero point calibration section includes:
When the curvature is in a linear region between a first right threshold curvature and a first left threshold curvature, the calibration value is a first calibration value,
When the curvature in the straight line area exceeds the first right threshold curvature, the calibration value is varied from the first calibration value to a second calibration value, and then the curvature is greater than the first right threshold curvature. When a second right threshold curvature close to zero is exceeded, the calibration value is varied from the second calibration value to the first calibration value;
When the curvature in the straight line area exceeds the second right threshold curvature, the calibration value is changed from the first calibration value to a third calibration value, and then the curvature is greater than the first left threshold curvature. changing the calibration value from the third calibration value to the first calibration value when a second left threshold curvature close to zero is exceeded;
The yaw rate calibration device according to claim 10.
The zero point calibration unit does not calibrate the zero point of the yaw rate sensor until a set time has elapsed after calibrating the zero point of the yaw rate sensor.
A yaw rate calibration device according to any one of claims 1 to 11.