Vehicle behavior notification device

Abstract

To provide a vehicle behavior informing device which informs a driver of subtle vehicle behavior which the driver is not able to perceive easily by sight.SOLUTION: A vehicle behavior informing device includes: a yaw rate detection part 102 which detects a yaw rate of a vehicle body of a vehicle; and an informing part 310 which informs a driver of the yaw rate detected by the yaw rate detection part.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to a vehicle behavior notification device that is provided in a vehicle such as an automobile and that notifies a driver of information relating to the vehicle behavior. [Background technology]

[0002] 2. Description of the Related Art It has been proposed to display information about the behavior of a vehicle such as an automobile to a driver or other passenger in the vehicle. As a technology relating to the display of information relating to vehicle behavior, Patent Document 1 describes a turning behavior display device that is provided in a vehicle having a turning behavior control means that controls the yaw moment of the vehicle based on the torque difference between the left and right wheels of the vehicle, and that displays the amount of yaw moment control by the turning behavior control means. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2009-29181 Summary of the Invention [Problem to be solved by the invention]

[0004] In everyday driving of a car, there are many opportunities to perform minute steering, for example, by turning the steering wheel at an angle of 5 degrees or less, and the frequency of such minute steering increases as the speed increases. The yaw rate generated in the vehicle by such small steering angle steering is often smaller than the lower limit of the yaw rate that the driver can visually perceive, making it difficult for the driver to accurately grasp the vehicle behavior that occurs in the small steering range, such as the initial steering when starting a turn or corrective steering while driving on a straight road. In such cases, even a small steering angle will cause vehicle behavior, but the driver may be under the illusion that no vehicle behavior is occurring, which can lead to inappropriate operations such as further excessive steering input or delayed steering return. Such inappropriate operation can cause the actual driving line to deviate from the driver's intended driving line (driving trajectory), resulting in increased steering frequency by the driver and erratic vehicle behavior. In view of the above-mentioned problems, an object of the present invention is to provide a vehicle behavior notification device that notifies a driver of minute vehicle behaviors that are difficult for the driver to visually recognize. [Means for solving the problem]

[0005] In order to solve the above-mentioned problems, a vehicle behavior notification device according to one aspect of the present invention includes a yaw rate detection unit that detects a yaw rate of a vehicle body, and a notification unit that notifies a driver of the yaw rate detected by the yaw rate detection unit. The notification unit notifies the yaw rate only when the absolute value of the yaw rate is equal to or less than a predetermined threshold value set as a lower limit value of the yaw rate that can be detected by the driver. It is characterized by the following. By notifying the driver of the yaw rate, the driver can obtain information about the vehicle's yaw rate from the notification unit, which the driver would normally obtain from vision such as the view ahead, and can recognize minute yaw rates that are difficult to recognize visually. By recognizing the minute vehicle behavior occurring within the vehicle, it becomes possible to make steering inputs that match the behavior, preventing excessive steering inputs and delays in steering returns, and suppressing the driver's steering frequency and wobbling when driving straight, making it possible to easily trace the driving trajectory intended by the driver. In the present invention, the threshold value can be set as a lower limit value of the yaw rate that is visually detectable by the driver.

[0006] In the present invention, the notification unit may be configured to notify the yaw rate only when the absolute value of the yaw rate is equal to or less than a predetermined threshold value. According to this, when the absolute value of the yaw rate is greater than the threshold value and the driver can recognize the yaw rate from the view ahead, etc., the notification of the yaw rate can be stopped and the driver can be guided to look ahead of the vehicle.

[0007] In the present invention, the vehicle control device may be configured to include a driver identification unit that identifies a driver, and a threshold setting unit that sets the threshold to a different value depending on the driver identified by the driver identification unit. This allows for the aforementioned effect to be enhanced by setting an appropriate threshold value for each driver, taking into consideration the fact that there are individual differences in the ability of drivers to visually detect yaw rate.

[0008] In the present invention, a steering operation detection unit that detects a steering operation by a driver is provided, and the notification unit can change the notification mode depending on whether or not the steering operation is detected. When a yaw rate occurs due to the driver's steering operation, the driver anticipates the occurrence of the yaw rate to some extent and can predict the occurrence of the yaw rate from the reaction force of the steering wheel. However, when a yaw rate occurs due to disturbances such as crosswinds, cant (inclination along the width of the lane) or irregularities on the road surface without the driver's steering operation, it is difficult for the driver to anticipate the occurrence of the yaw rate. In this regard, according to the present invention, the manner in which information relating to the yaw rate is notified varies depending on whether or not a steering operation is detected, thereby making it possible to draw the driver's attention to unexpected vehicle behavior.

[0009] In the present invention, the notification unit may be configured to stop notifying the yaw rate when the absolute value of the yaw rate is equal to or less than a predetermined lower limit value. According to this, when no yaw rate is occurring or when the yaw rate is small enough to be ignored, the yaw rate is not notified, thereby reducing the annoyance felt by the driver due to the notification of unnecessary information. [Effects of the Invention]

[0010] As described above, according to the present invention, it is possible to provide a vehicle behavior notification device that notifies a driver of minute vehicle behaviors that are difficult for the driver to visually recognize. [Brief explanation of the drawings]

[0011] [Figure 1] 1 is a block diagram showing the configuration of a first embodiment of a vehicle behavior notification device to which the present invention is applied. [Figure 2] 1 is a diagram schematically illustrating a configuration of a steering device for a vehicle according to a first embodiment. [Figure 3] 3 is a flowchart showing the operation of the vehicle behavior notification device of the first embodiment. [Figure 4] 3 is a diagram schematically illustrating an example of a yaw rate notification mode in the vehicle behavior notification device of the first embodiment. FIG. [Figure 5] 1 is a diagram schematically showing an example of a transition in vehicle behavior when a vehicle having the vehicle behavior notification device of the first embodiment and a comparative vehicle are traveling on a straight road; [Figure 6] 1 is a diagram schematically showing an example of a transition in vehicle behavior when a vehicle having the vehicle behavior notification device of the first embodiment and a comparative example vehicle are traveling on a curved road. FIG. [Figure 7] 10 is a diagram schematically showing an example of a yaw rate notification mode in a vehicle behavior notification device according to a second embodiment of the present invention. FIG. [Figure 8] 10 is a diagram schematically showing an example of a yaw rate notification mode in a vehicle behavior notification device according to a third embodiment of the present invention. FIG. [Figure 9] FIG. 10 is a diagram schematically illustrating an example of a yaw rate notification mode in a vehicle behavior notification device according to a fifth embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0012] First Embodiment A first embodiment of a vehicle behavior notification device to which the present invention is applied will be described below. The vehicle behavior notification device of the first embodiment is mounted on an automobile such as a passenger car, for example. FIG. 1 is a block diagram that schematically shows the configuration of a vehicle behavior notification device according to the first embodiment. The vehicle behavior notification device 1 includes a behavior control unit 100, a hydraulic control unit 110, a steering control unit 200, and a behavior display control unit 300. Each unit can be configured as a microcomputer having, for example, an information processing unit such as a CPU, a storage unit such as a RAM or a ROM, an input / output interface, a bus connecting these, and the like. In addition, each unit can communicate with each other directly or via an in-vehicle LAN such as a CAN communication system, and transmit various types of information.

[0013] The behavior control unit 100 is a braking control device that controls hydraulic service brakes (braking devices) (not shown) provided on each wheel of the vehicle. The behavior control unit 100 can individually control the brake fluid pressure in the wheel cylinder 112 of each wheel by issuing commands to the hydraulic control unit 110, thereby generating the desired braking force in the service brake of each wheel. The behavior control unit 100 is connected to a vehicle speed sensor 101, a yaw rate sensor 102, and the like. The vehicle speed sensor 101 detects the rotation speed (wheel speed) of each wheel. The yaw rate sensor 102 detects the yaw rate, which is the rotation speed of the vehicle body around the vertical axis. The outputs of the vehicle speed sensor 101 and the yaw rate sensor 102 are used for anti-lock brake control, attitude stabilization control, etc., which will be described below.

[0014] Antilock brake control is a control method for restoring wheel rotation by reducing the brake fluid pressure in a wheel that has locked during braking, for example. The attitude stabilization control generates a difference in braking force between the left and right wheels when the vehicle is oversteered or understeered, thereby generating a yaw moment in a direction that suppresses these behaviors. The behavior control unit 100 calculates a target yaw rate, which is a yaw rate that can occur in the vehicle body during normal driving, based on the steering angle of the steering device obtained from the steering control unit 200 and the vehicle speed detected by the vehicle speed sensor 101. The behavior control unit 100 sets the direction and magnitude of the yaw moment to be generated by controlling the braking force according to the deviation between the actual yaw rate detected by the yaw rate sensor 102 and the target yaw rate.

[0015] The hydraulic control unit 110 is a hydraulic pressure control device that individually adjusts the brake fluid pressure in the wheel cylinders 112 of the respective wheels. The hydraulic control unit 110 includes an electric pump that pressurizes the brake fluid, and a pressure increase valve, a pressure reduction valve, a pressure maintenance valve, and the like that control the brake fluid pressure in each wheel cylinder 112 .

[0016] The hydraulic control unit 110 is connected to a master cylinder 111, a wheel cylinder 112, etc. via brake fluid piping. The master cylinder 111 pressurizes brake fluid in response to the operation of a brake pedal (not shown) by the driver to perform a braking operation. The brake fluid pressure generated by the master cylinder 111 is transmitted to the wheel cylinder 112 via the hydraulic control unit 110 . The hydraulic control unit 110 has a function of increasing or decreasing the brake fluid pressure in each wheel cylinder 112 by overriding the brake fluid pressure generated by the master cylinder 111 . The wheel cylinders 112 are provided on the respective wheels, and generate frictional force (braking force) according to the brake fluid pressure, for example, by pressing brake pads against disc rotors.

[0017] The steering control unit 200 controls a steering device that steers the front wheels, which are the steerable wheels of the vehicle. FIG. 2 is a diagram schematically showing the configuration of the steering device for a vehicle according to the first embodiment. The steering device is provided with, for example, a pinion-assist type electric power steering device (EPS) as a power assist mechanism.

[0018] The steering device is configured to include a steering wheel 210, a steering shaft 220, an intermediate shaft 221, a pinion shaft 222, a rack shaft 230, a rack housing 240, a tie rod 250, a housing 260, an actuator unit 270, and the like.

[0019] The steering wheel 210 is an annular operating member that is turned by the driver to input a steering operation. The steering wheel 210 is disposed in the vehicle interior facing the driver's seat.

[0020] The steering shaft 220 is a rotating shaft with one end attached to the steering wheel 210, and transmits the rotational movement of the steering wheel 210 to a rack and pinion mechanism that converts it into translational movement in the vehicle width direction. An intermediate shaft 221 and a pinion shaft 222 are connected in this order to the end of the steering shaft 220 opposite to the steering wheel 210 side.

[0021] Universal joints (Cardan joints) 223, 224 are provided between the steering shaft 220 and the intermediate shaft 221, and between the intermediate shaft 221 and the pinion shaft 222, respectively, so that rotation can be transmitted when the shafts are bent. A pinion gear that meshes with a rack gear 231 of the rack shaft 230 to drive the rack shaft 230 is formed at the tip of the pinion shaft 222 .

[0022] The rack shaft 230 is a columnar member arranged so that its longitudinal direction (axial direction) is aligned with the vehicle width direction. The rack shaft 230 is supported so as to be able to translate in the vehicle width direction relative to the vehicle body. A rack gear 231 that meshes with the pinion gear of the pinion shaft 222 is formed on a part of the rack shaft 230 . In response to the rotation of the steering shaft 220, the rack gear 231 of the rack shaft 230 is driven by the pinion gear, and the rack shaft 230 moves in a translational (straight) direction along the vehicle width direction.

[0023] The rack housing 240 is a substantially cylindrical member that accommodates and supports the rack shaft 230 so that the rack shaft 230 can be relatively displaced along the vehicle width direction. Rack boots 241 are provided on both ends of the rack housing 240 . The rack boot 241 is a member that prevents foreign matter such as dust from entering the rack housing 240 while allowing the tie rod 250 to move relative to the rack housing 240 . The rack boot 241 is made of a resin material such as elastomer and has a flexible bellows-like shape.

[0024] The tie rod 250 is a shaft-shaped interlocking member that connects the end of the rack shaft 230 and the knuckle arm 261 of the housing 260, and rotates the housing 260 around the kingpin axis in conjunction with the translational movement of the rack shaft 230. The inner end of the tie rod 250 in the vehicle width direction is swingably connected to the end of the tie rod 230 via a ball joint 251 . The outer end of the tie rod 250 in the vehicle width direction is connected to a knuckle arm 261 of a housing 260 via a ball joint 252 . A turnbuckle mechanism for toe-in adjustment is provided at the connection between the tie rod 250 and the ball joint 252.

[0025] The housing (knuckle, upright) 260 is a member that houses a hub bearing that supports the wheel W rotatably around the axle. The housing 260 has a knuckle arm 261 formed to protrude forward or rearward relative to the axle. The housing 260 is supported so as to be rotatable around a kingpin axis, which is a predetermined rotational center axis. For example, if the vehicle's front suspension is a MacPherson strut, the kingpin axis is an imaginary axis connecting the center of the bearing of the strut top mount and the center of the ball joint that connects the lower part of the housing 260 and the transverse link (lower arm). The housing 260 is pushed and pulled in the vehicle width direction by the rack shaft 230 via the tie rod 250, thereby rotating about the kingpin axis and steering the wheels W.

[0026] The actuator unit 270 is a drive device that rotates and drives the pinion shaft 222 to provide power assistance during manual driving and to perform steering operations during automatic driving. The actuator unit 270 includes a motor 271, a gear box 272, and the like. The motor 271 is an electric actuator that generates a driving force to be applied to the steering shaft 220 . The rotation direction and output torque of the motor 271 are controlled by the steering control unit 200 . The gear box 272 includes a reduction gear train that reduces the speed (torque amplification) of the rotation output of the motor 271 and transmits it to the pinion shaft 222.

[0027] The steering control unit 200 is connected to a steering angle sensor 201, a torque sensor 202, and the like. The steering angle sensor 201 and the torque sensor 202 are, for example, integrated and provided in an area of ​​the pinion shaft 222 closer to the steering wheel 210 than the actuator unit 270 is. The steering angle sensor 201 has an angle encoder that detects the rotational angle position of the pinion shaft 220 (which is substantially equal to the rotational angle position of the steering wheel 210). Torque sensor 202 detects torque acting on pinion shaft 220 (such as input torque from steering wheel 210).

[0028] The behavior display control unit 300 displays the actual yaw rate of the vehicle body (actual yaw rate) detected by the yaw rate sensor 102 on the yaw rate display section 310 in a predetermined display mode in a predetermined case. The yaw rate display unit 310 is a display device (notification unit) that is provided on, for example, an instrument panel inside the vehicle, and displays the magnitude and direction of the yaw rate to the driver. The functions of the behavior display control unit 300 and the yaw rate display unit 310 will be described in detail below.

[0029] FIG. 3 is a flowchart showing the operation of the vehicle behavior notification device of the first embodiment. Each step will be explained in order below. <Step S01: Obtain yaw rate> The behavior display control unit 300 acquires information about the yaw rate of the vehicle body acquired by the yaw rate sensor 102 via the behavior control unit 100 . The information about the yaw rate includes information about the magnitude (absolute value) and direction (clockwise (right turn) or counterclockwise (left turn) when viewed from above the vehicle) of the yaw rate. Then, proceed to step S02.

[0030] <Step S02: Determine whether yaw rate is occurring> The behavior display control unit 300 determines whether or not the absolute value of the yaw rate acquired in step S01 is equal to or greater than a predetermined lower limit value. This lower limit value is set in consideration of determining whether a state in which no yaw rate is occurring or a state in which a yaw rate is occurring but is so small that it can be ignored. If a yaw rate whose absolute value is equal to or greater than the lower limit value is occurring, the process proceeds to step S03, and otherwise (if no yaw rate is actually occurring), the series of processes is ended (returned).

[0031] <Step S03: Determine whether yaw rate is below threshold> The behavior display control unit 300 determines whether or not the absolute value of the yaw rate acquired in step S02 is equal to or less than a predetermined threshold value (upper limit value for displaying the yaw rate). This threshold value is set in consideration of the lower limit of the yaw rate that the driver can detect based on, for example, the view ahead of the vehicle. For example, the threshold value can be set to about 0.2 to 0.5 deg / sec. In addition, since there are individual differences in the lower limit of the yaw rate that a driver can detect visually, the threshold value may be changed for each driver using, for example, a driver monitoring system that captures an image of the driver with a camera or the like and identifies the individual. For example, in the case of a driver with a high ability to detect yaw rate, swaying of the vehicle when traveling on a straight road is suppressed. Therefore, in the case of a driver who has a small deviation in the lateral position within the lane that is successively detected by an environment recognition means such as a stereo camera during manual driving, the threshold value can be reduced as the driver has a high ability to detect yaw rate. The behavior display control unit 300 has a function as a threshold setting unit of the present invention. If the absolute value of the yaw rate is equal to or less than the threshold value, the process proceeds to step S04, otherwise the series of processes is ended (returned).

[0032] <Step S04: Obtaining steering angle δ> The behavior display control unit 300 acquires information relating to the steering angle δ detected by the steering angle sensor 201 via the steering control unit 200 . Then, proceed to step S05.

[0033] <Step S05: Determining Whether Steering Operation Is Present> The behavior display control unit 300 compares the absolute value of the steering angle δ acquired in step S04 with a predetermined value set in advance to determine whether or not the driver is performing a steering operation. This predetermined value is set in consideration of distinguishing between a state in which there is no steering operation by the driver or the steering operation is substantially negligible and a state in which an active steering operation by the driver is detected. For example, the predetermined value can be set taking into consideration the steering angle that inevitably occurs due to input from the road surface, shimmy vibration of the steering system, etc., even when the driver is not steering. If the absolute value of the steering angle δ is equal to or greater than the predetermined value, the process proceeds to step S06, otherwise the process proceeds to step S07.

[0034] <Step S06: Yaw rate display (pattern A)> The behavior display control unit 300 causes the yaw rate display section 310 to display the magnitude and direction of the current yaw rate. The display mode at this time is a display mode of pattern A, which is different from pattern B, which will be described later. Display patterns A and B will be explained in detail later. After that, the series of processes is ended (returned).

[0035] <Step S07: Yaw rate display (pattern B) The behavior display control unit 300 causes the yaw rate display section 310 to display the magnitude and direction of the current yaw rate. The display mode at this time is pattern B. After that, the series of processes is ended (returned).

[0036] FIG. 4 is a diagram schematically showing an example of a yaw rate notification mode in the vehicle behavior notification device of the first embodiment. 4(a) and 4(b) show the above-mentioned patterns A and B, respectively. The yaw rate display unit 310 is provided, for example, near the lower end of the windshield WS, which is the front window glass portion of the vehicle, and can be configured as a rectangular image display device having a longitudinal direction along the vehicle width direction.

[0037] The yaw rate display unit 310 has a function of displaying a yaw rate indicator 311 . The yaw rate indicator 311 is located in the center of the yaw rate display unit 310 in the vehicle width direction when the yaw rate is 0, and is displaced in the vehicle width direction when a yaw rate occurs. The amount of displacement of the yaw rate indicator 311 from the center correlates with the magnitude of the absolute value of the yaw rate, and for example, the amount of displacement can be configured to be proportional to the absolute value of the yaw rate. The direction of displacement of the yaw rate indicator 311 from the center indicates the direction of the yaw rate. That is, when a counterclockwise yaw rate occurs, the indicator displaces leftward from the center, and when a clockwise yaw rate occurs, the indicator displaces rightward from the center. This type of display allows the driver to recognize the quantitative yaw rate as well as its direction.

[0038] In the first embodiment, the display color of the yaw rate indicator 311 is different between pattern A shown in FIG. 4(a) (when a steering operation is performed) and pattern B shown in FIG. 4(b) (when no steering operation is performed). In pattern B, since it is considered that the driver often does not anticipate the occurrence of yaw rate, the yaw rate indicator 311 is displayed in a warning color such as red, orange, or yellow, or a similar color, in order to draw more attention to the driver. On the other hand, in pattern A, the mark is displayed not in warning colors, but in colors such as blue or green.

[0039] The effects of the first embodiment described above will be explained below in comparison with a comparative example of the present invention, which will be explained below. The vehicle of the comparative example is a vehicle that is not equipped with the vehicle behavior notification device of the first embodiment. In the comparative vehicle, the driver visually determines the yaw rate of the vehicle body from the view ahead.

[0040] FIG. 5 is a diagram showing an example of a transition in vehicle behavior when a vehicle having the vehicle behavior notification device of the first embodiment and a comparative vehicle are traveling on a straight road. FIG. 5(a) shows the behavior of the vehicle in a comparative example, and FIG. 5(b) shows the behavior of the vehicle in the first embodiment (the same applies to FIG. 6 described later). In the comparative example shown in FIG. 5(a), after a counterclockwise yaw rate occurs in the vehicle V due to, for example, an external disturbance, the driver recognizes the yaw rate visually or otherwise at a position P01. Thereafter, the driver attempts to make a correction by steering to the right at position P02, but the timing of inputting the corrective steering is delayed compared to the first embodiment, resulting in a larger fluctuation in the wobble. Furthermore, because the driver is slow to recognize the clockwise yaw rate generated by this corrective steering, the driver may mistakenly believe that no behavior is occurring and the corrective steering angle may become excessive, resulting in poor convergence, such as an overshoot from the driving line to which the vehicle should have returned at position P03.

[0041] In contrast, in the first embodiment shown in Figure 5(b), the driver recognizes the occurrence of yaw rate at position P11 earlier than at position P01 in the comparative example, and can apply corrective steering earlier at position P12, thereby reducing the vehicle's vibration amplitude. In addition, since the driver can quickly recognize the yaw rate caused by the corrective steering, excessive corrective steering can be suppressed and convergence can be improved.

[0042] FIG. 6 is a diagram showing an example of a transition in vehicle behavior when a vehicle having the vehicle behavior notification device of the first embodiment and a comparative example vehicle are traveling on a curved road. In the comparative example shown in FIG. 6(a), the driver cannot recognize the vehicle behavior unless the yaw rate generated in response to the driver's steering input exceeds the minimum value that can be visually recognized. This creates the illusion that no vehicle behavior occurs in response to the steering, and the driver ends up performing excessive steering (for example, increasing the steering angle (turning further)) at position P21 in order to cause the behavior. The driver then recognizes the yaw rate, but excessive steering causes the line to deviate inward from the line intended by the driver at position P22, requiring corrective steering, making it difficult for the driver to trace the line originally intended. Furthermore, there is a concern that the vehicle posture during cornering may become unstable due to unnecessary steering and steering back.

[0043] In contrast, in the first embodiment shown in Figure 6(b), the driver can recognize early on, for example at position P31, that the vehicle has behaved in response to the steering input, and excessive steering operation can be suppressed, making it possible to easily trace the line intended by the driver.

[0044] According to the first embodiment described above, the following effects can be obtained. (1) By quantitatively displaying the yaw rate to the driver, the driver can obtain information about the vehicle's yaw rate from the yaw rate display unit 310, which the driver normally obtains from the view ahead, etc., and can recognize minute yaw rates that are difficult to recognize visually. By recognizing the minute vehicle behavior occurring within the vehicle, it becomes possible to make steering inputs that match the behavior, preventing excessive steering inputs and delays in steering returns, and suppressing the driver's steering frequency and wobbling when driving straight, making it possible to easily trace the driving trajectory intended by the driver. (2) If the absolute value of the yaw rate is greater than the threshold value and the driver can recognize the yaw rate from the view ahead, the display of the yaw rate can be stopped and the driver can be guided to look ahead of the vehicle. (3) By varying the threshold for the yaw rate display depending on the driver, it is possible to take into account the individual differences in drivers' ability to visually detect yaw rate, and to set an appropriate threshold for each driver, thereby promoting the above-mentioned effects. (4) By changing the display color of the yaw rate indicator 311 depending on whether or not a steering operation is detected, the driver's attention can be drawn to unexpected vehicle behavior. (5) By not displaying the yaw rate when no yaw rate is actually occurring, it is possible to reduce the annoyance felt by the driver due to the notification of unnecessary information.

[0045] Second Embodiment Next, a second embodiment of a vehicle behavior notification device to which the present invention is applied will be described. In the following embodiments, the same reference numerals are used to designate parts common to the previous embodiments, and explanations thereof will be omitted, with differences being mainly described. FIG. 7 is a diagram showing an example of a yaw rate notification mode in the second embodiment of the vehicle behavior notification device to which the present invention is applied. In the second embodiment, instead of the yaw rate display unit 310 of the first embodiment, an image of a yaw rate indicator 312 is displayed below the windshield WS by a head-up display (HUD) device (not shown). The yaw rate indicator 312 is formed in the shape of an arrow pointing ahead of the vehicle when no yaw rate is occurring, for example. When a yaw rate occurs, the yaw rate indicator 312 displays the direction and magnitude of the yaw rate according to the rotation direction and rotation angle. Furthermore, the display colors of the patterns A and B are different, similar to the yaw rate indicator 311 of the first embodiment. In the second embodiment described above, the same effects as those of the first embodiment can be obtained.

[0046] <Third embodiment> Next, a third embodiment of a vehicle behavior notification device to which the present invention is applied will be described. FIG. 8 is a diagram showing an example of a yaw rate notification mode in the vehicle behavior notification device according to the third embodiment of the present invention. In the third embodiment, a yaw rate indicator 313 and a pitch rate indicator 314 are displayed on the windshield WS by a head-up display device similar to that in the second embodiment. The yaw rate indicator 313 is, for example, a linear display extending in the vertical direction, and similar to the yaw rate indicator 311 of the first embodiment, displays the direction and magnitude of the yaw rate by moving in the horizontal direction. The pitch rate indicator 314 displays information about the angular velocity of the vehicle's pitch direction behavior. The pitch rate indicator 314 is, for example, a linear display extending horizontally. For example, when a pitching behavior in the nose-down direction occurs in the vehicle body, the pitch rate indicator 314 moves downward from a predetermined neutral position according to the magnitude of the angular velocity (pitch rate). The yaw rate indicator 313 and the pitch rate indicator 314 may be configured to display different colors for patterns A and B. According to the third embodiment described above, in addition to the same effects as those of the first embodiment described above, by displaying the angular velocity (pitch rate) of the pitching behavior, the driver can be made to recognize the minute behavior of the vehicle in a more multifaceted and intuitive manner.

[0047] <Fourth embodiment> Next, a fourth embodiment of a vehicle behavior notification device to which the present invention is applied will be described. In the fourth embodiment, instead of the yaw rate display unit 310 of the first embodiment, an audio output device such as a speaker or buzzer is used to notify the direction and magnitude of the yaw rate by audio information. For example, the direction of the yaw rate can be indicated by a tone, and the magnitude of the yaw rate can be notified by the pitch, volume, or change in tone. Furthermore, the patterns A and B can be configured to have different tones. According to the fourth embodiment described above, in addition to the same effects as those of the first embodiment described above, it is possible to transmit information about vehicle behavior even when the driver is looking ahead of the vehicle.

[0048] Fifth Embodiment Next, a fifth embodiment of a vehicle behavior notification device to which the present invention is applied will be described. FIG. 9 is a diagram schematically showing an example of a yaw rate notification mode in the fifth embodiment of the vehicle behavior notification device to which the present invention is applied. In the fifth embodiment, an image display unit, such as a yaw rate indicator 315, is displayed on the yaw rate display unit 310, which is an image display unit, showing a schematic plan view or bird's-eye view of the vehicle, and the direction and magnitude of the yaw rate are displayed by rotating the yaw rate indicator 315, similar to the yaw rate indicator 312 of the second embodiment. Also, similarly to the first embodiment, the display color of the yaw rate indicator 315 may be different between patterns A and B, or some kind of warning display may be added only in the case of pattern B. According to the fifth embodiment described above, in addition to the same effects as those of the first embodiment described above, by displaying the yaw rate by the rotation of the yaw rate indicator 315 that resembles a vehicle, even a driver with little prior knowledge can intuitively understand the meaning of the display.

[0049] (Variation) The present invention is not limited to the above-described embodiments, and various modifications and variations are possible, and these are also within the technical scope of the present invention. (1) The configurations of the vehicle behavior notification device and the vehicle are not limited to the above-described embodiments, and may be modified as appropriate. (2) The display (notification) modes in each embodiment are merely examples and may be modified as appropriate. For example, various display devices may be used, such as pointer-type meters and bar graph display devices with an array of light-emitting elements such as LEDs, in addition to image display devices and head-up display devices. Furthermore, notification by audio information as in the fourth embodiment may be combined with a visual display. (3) In each embodiment, the presence or absence of a steering operation by the driver is determined based on the steering angle, but this is not limiting and other methods may be used for determination. For example, the presence or absence of a steering operation may be determined based on the output of a torque sensor that detects steering torque. [Explanation of symbols]

[0050] 1 Vehicle behavior notification device 100 Behavior control unit 101 Vehicle speed sensor 102 Yaw rate sensor 110 Hydraulic control unit 111 Master cylinder 112 Wheel cylinder 200 steering control unit 201 steering angle sensor 202 Torque sensor 210 Steering wheel 220 Steering shaft 221 Intermediate shaft 222 Pinion shaft 223,224 Universal joint 230 Rack shaft 231 Rack gear 240 Rack housing 241 Rack boots 250 tie rod 251,252 ball joint 260 Housing 261 Knuckle arm 270 Actuator unit 271 Motor 272 Gearbox 300 behavior display control unit 310 yaw rate display unit 311,312,313,315 Yaw rate indicator 314 Pitch Rate Indicator V vehicle

Claims

1. A yaw rate detection unit that detects the yaw rate of a vehicle body; a notification unit that notifies a driver of the yaw rate detected by the yaw rate detection unit; Equipped with The notification unit notifies the yaw rate only when the absolute value of the yaw rate is equal to or less than a predetermined threshold value set as a lower limit value of the yaw rate that can be detected by a driver. A vehicle behavior notification device characterized by:

2. The threshold value is set as the lower limit of the yaw rate that can be visually detected by the driver.

2. The vehicle behavior notification device according to claim 1, wherein:

3. A driver identification unit that identifies the driver; a threshold setting unit that sets the threshold to a different value depending on the driver identified by the driver identifying unit; 3. The vehicle behavior notification device according to claim 1, further comprising:

4. A steering operation detection unit that detects a steering operation by the driver, The notification unit changes a notification mode depending on whether the steering operation is detected or not.

4. The vehicle behavior notification device according to claim 1, wherein:

5. When the absolute value of the yaw rate is equal to or less than a predetermined lower limit value that indicates a state in which a yaw rate is not occurring, the notification unit determines that a yaw rate is not occurring and stops notifying the yaw rate.

5. The vehicle behavior notification device according to claim 1, wherein:

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