Vision assist apparatus

Abstract

To suppress motion sickness of an occupant caused by turning operation of a vehicle.SOLUTION: The control unit calculates a yaw rate of the traveling vehicle based on a steering angle of a steering wheel of the vehicle and a vehicle speed of the vehicle while the vehicle is traveling, and moves the object displayed on the front window by the display unit in a left-right direction of the front window by a movement amount corresponding to the yaw rate.SELECTED DRAWING: Figure 7

Description

[Technical Field]

[0001] The present invention relates to a visual aid device. [Background technology]

[0002] Occupants of a moving vehicle maintain their sense of balance by predicting the vehicle's behavior using visual information received through the eyes and vestibular sensations such as gravity or centrifugal force sensed by the vestibular apparatus of the inner ear (semicircular canals and otoliths). When a discrepancy occurs between the vehicle's behavior predicted by visual information and vestibular sensation and the actual vehicle behavior, the occupant develops motion sickness (motion sickness). Therefore, technologies are known to suppress motion sickness in occupants of a moving vehicle.

[0003] For example, Patent Document 1 discloses a technology that suppresses motion sickness in occupants by detecting the vehicle's inclination relative to the horizontal direction using an acceleration sensor and a gyro sensor, and displaying a horizontal image indicating the horizontal around the occupant's face. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent Publication No. 2021-115911 Summary of the Invention [Problem to be solved by the invention]

[0005] Incidentally, vehicle behaviors predicted by a passenger in a moving vehicle include, for example, tilting in the roll direction and turning in the yaw direction. The tilting is a rotational movement of the vehicle around the roll axis, i.e., a movement of the vehicle tilting left or right relative to the ground. The turning is a rotational movement of the vehicle around the yaw axis, i.e., a turning movement of the vehicle along the road. Prediction of turning movements of the vehicle relies on visual information. In particular, when driving a vehicle in an environment such as rain, snow, or thick fog, poor visibility limits the visibility of the passenger, making it difficult for the passenger to predict the turning movement of the vehicle using visual information. Therefore, a discrepancy occurs between the turning movement of the vehicle predicted by the passenger and the actual turning movement of the vehicle, making the passenger more susceptible to motion sickness.

[0006] The technology described in Patent Document 1 displays a horizontal image around the occupant's face, thereby eliminating the discrepancy between the vehicle's roll tilt predicted by the occupant and the actual vehicle tilt. This makes it possible to suppress the onset of motion sickness. However, the technology described in Patent Document 1 does not allow the occupant to visually predict the vehicle's turning motion in the yaw direction using the horizontal image, so the actual turning motion causes motion sickness. For this reason, there has been a need for a technology that allows the occupant to visually recognize the turning motion of a moving vehicle, even when the occupant's field of vision is limited due to poor visibility or the like, thereby suppressing motion sickness in the occupant.

[0007] Therefore, an object of the present invention is to provide a visual support device that can suppress motion sickness in occupants caused by the turning motion of a vehicle. [Means for solving the problem]

[0008] In order to solve the above problem, a visual support device according to an embodiment of the present invention comprises: a display unit that displays a visual support object on a front window of the vehicle; a control unit that controls the display of the object by the display unit; Equipped with The control unit calculating a yaw rate of the vehicle while the vehicle is traveling based on a steering angle of a steering wheel of the vehicle and a vehicle speed of the vehicle; The object displayed on the windshield by the display unit is moved in the left-right direction of the windshield by an amount corresponding to the yaw rate. [Effects of the Invention]

[0009] According to the present invention, it is possible to provide a visual support device that can suppress motion sickness in an occupant caused by a turning motion of a vehicle. [Brief explanation of the drawings]

[0010] [Figure 1] 1 is a diagram showing the behavior of a vehicle predicted by a visual support device according to an embodiment of the present invention; [Figure 2] 2 is a block diagram showing the configuration of a vehicle equipped with the visual support device according to the embodiment; FIG. [Figure 3] FIG. 2 is a block diagram showing a hardware configuration of the visual support device according to the embodiment. [Figure 4] FIG. 2 is a block diagram showing a functional configuration of the visual support device according to the embodiment. [Figure 5] 10A and 10B are diagrams showing specific examples of visual support objects that are displayed on the front window by the visual support device according to the embodiment. [Figure 6] 4 is a Bode diagram for explaining a yawing resonance frequency of a vehicle equipped with the visual support device according to the embodiment. FIG. [Figure 7] 10A and 10B are diagrams illustrating an outline of movement of a visual support object displayed on a front window by the visual support device according to the embodiment. [Figure 8] 10A and 10B are diagrams illustrating the movement amount and rotation angle of a visual support object displayed on the front window by the visual support device according to the embodiment. [Figure 9] 10 is a flowchart illustrating the flow of a display control process executed by the visual support device according to the embodiment. [Figure 10]10A and 10B are diagrams showing other specific examples of visual support objects that are displayed on the front window by the visual support device according to the embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0011] Embodiments of the present invention will be described in detail below with reference to the accompanying drawings. Specific dimensions, materials, numerical values, etc. shown in the embodiments are merely examples for facilitating understanding of the invention and, unless otherwise specified, do not limit the present invention. Furthermore, the relative sizes of components shown in each drawing do not necessarily accurately represent the actual size relationships between the components. In this specification and drawings, elements having substantially the same function and configuration are designated by the same reference numerals to avoid redundant description, and elements not directly related to the present invention are not shown.

[0012] (1. Overview of visual support devices) An overview of a visual support device 10 according to one embodiment of the present invention will be described. The visual support device 10 according to this embodiment is a device that is optionally installed in a vehicle 1 in order to suppress motion sickness (motion sickness) of occupants, for example.

[0013] Incidentally, when a vehicle occupant experiences motion sickness while traveling, it is due to a discrepancy between the predicted vehicle behavior and the actual vehicle behavior. Occupants predict the vehicle's behavior and maintain their sense of balance using visual information obtained from their eyes and vestibular sensations such as gravity or centrifugal force sensed by the vestibular organs of the inner ear (semicircular canals and otoliths). For example, visual information includes the flow of the scenery outside the vehicle window, the presence or absence of obstacles, the presence or absence of traffic lights, and the condition of the road surface (e.g., unevenness). Therefore, when a vehicle is traveling in an environment such as rain, snow, or thick fog, if the occupant's field of vision is restricted by poor visibility, visual information is also restricted, making it difficult to predict the vehicle's behavior. As a result, a discrepancy occurs between the predicted vehicle behavior and the actual vehicle behavior, leading to the onset of motion sickness (motion sickness).

[0014] Therefore, the visual support device 10 is configured to calculate parameters (e.g., yaw rate, pitch angle, roll angle, etc.) that represent the behavior of the vehicle 1 based on information acquired from the vehicle 1 while it is traveling (e.g., steering angle of the steering wheel, vehicle speed of the vehicle 1, accelerator operation amount of the vehicle 1, etc.), and to move or rotate an object displayed on the windshield based on the calculation results. With this configuration, even in conditions such as poor visibility, the occupant can visually recognize and predict the behavior of the vehicle 1 from the object displayed on the windshield. As a result, the occurrence of motion sickness in the occupant is suppressed.

[0015] (1.1. Vehicle Behavior) The behavior of a vehicle 1 calculated by a visual support device 10 according to this embodiment will be described with reference to FIG. 1. FIG. 1 is an explanatory diagram for explaining the behavior of a traveling vehicle 1. In FIG. 1 and the following figures, the roll axis X, pitch axis Y, and yaw axis Z intersect perpendicularly with each other at the center of gravity C of the vehicle 1. The roll axis X is an axis extending in the front-to-rear direction of the vehicle 1. The pitch axis Y is an axis extending in the left-to-right direction of the vehicle 1. The yaw axis Z is an axis extending in the up-and-down direction of the vehicle 1. The plane including the roll axis X and pitch axis Y is a horizontal plane. The plane including the roll axis X and yaw axis Z is a vertical plane parallel to the front-to-rear direction of the vehicle 1. The plane including the pitch axis Y and yaw axis Z is a vertical plane parallel to the left-to-right direction of the vehicle 1.

[0016] The visual support device 10 calculates the behavior of the vehicle 1 by calculating rotational movements about a roll axis X, a pitch axis Y, and a yaw axis Z, which are perpendicular to each other and centered around the center of gravity C of the vehicle 1, as shown in FIG. 1. As shown in FIG. 1, a rotational movement (rolling movement) about the roll axis X, in which the vehicle 1 rotates in the R1 direction or the R2 direction around the roll axis X, is a movement in which the vehicle 1 tilts left and right relative to the ground. A rotational movement (pitching movement) about the pitch axis Y, in which the vehicle 1 rotates in the P1 direction or the P2 direction around the pitch axis Y, is a movement in which the vehicle 1 tilts forward and backward relative to the ground. A rotational movement (yawing movement) about the yaw axis Z, in which the vehicle 1 rotates in the Y1 direction or the Y2 direction around the yaw axis Z, is a turning movement in which the vehicle 1 turns along the road.

[0017] (2. Vehicle Configuration) As described above, the visual support device 10 may be, for example, a device that is optionally and detachably installed on the vehicle 1, but is not limited to such an example, and the visual support device 10 may also be permanently installed on the vehicle 1. The configuration of the vehicle 1 on which the visual support device 10 according to this embodiment is installed will be described with reference to Fig. 2. Fig. 2 is a diagram showing a schematic configuration of the vehicle 1 on which the visual support device 10 is installed.

[0018] The vehicle 1 in which the visual support device 10 is installed may be, for example, an engine vehicle using an engine as a driving source. However, the vehicle 1 is not limited to an engine vehicle. The vehicle 1 may be, for example, an electric vehicle using a motor as a driving source, or a hybrid vehicle using an engine and a motor as driving sources.

[0019] As shown in FIG. 2, the vehicle 1 includes a visual assistance device 10, a vehicle control device 11, a sensor group 12, a steering wheel 13, an accelerator pedal 14, a brake pedal 15, a steering mechanism 16, a braking mechanism 17, a drive mechanism 18, and a windshield 19.

[0020] As described above, the visual support device 10 calculates the behavior of the vehicle 1 based on the steering angle of the steering wheel 13, the vehicle speed of the vehicle 1, the accelerator operation amount of the vehicle 1, specifications of the vehicle 1, etc. For example, the visual support device 10 calculates the behavior of the vehicle 1 based on the steering angle of the steering wheel 13 acquired from the steering angle sensor 124, the vehicle speed of the vehicle 1 acquired from the vehicle speed sensor 121, the accelerator operation amount acquired from an accelerator position sensor (not shown), specifications of the vehicle 1, etc. Here, the behavior of the vehicle 1 calculated by the visual support device 10 is, for example, a tilting motion of the vehicle 1 to the left or right (rotational motion around the roll axis X), a tilting motion of the vehicle 1 to the up or down (rotational motion around the pitch axis Y), and a turning motion of the vehicle 1 turning along the road (rotational motion around the yaw axis Z). As will be described in detail later, when a tilting motion of the vehicle 1 to the left or right occurs, the visual support device 10 expresses the tilt direction (left or right) and the degree of tilting motion as a roll angle Φ. Furthermore, when the vehicle 1 tilts up or down, the tilt direction (up or down) and degree of the tilting motion are represented by a pitch angle θ. Furthermore, when the vehicle 1 turns along the road, the degree of the turning motion is represented by a yaw rate γ. That is, the visual support device 10 calculates the roll angle Φ, pitch angle θ, and yaw rate γ of the vehicle 1 as the behavior of the vehicle 1 based on the steering angle of the steering wheel 13, the vehicle speed, the accelerator operation amount of the vehicle 1, the specifications of the vehicle 1, etc.

[0021] The visual support device 10 is also a device for displaying a visual support object on the windshield 19. The visual support object is, for example, a horizontal line L1 (see FIG. 5 ) that indicates the behavior of the vehicle 1. The visual support device 10 is configured, for example, as a head-up display that projects visual information such as various images and text onto the windshield 19. When the visual support device 10 projects the horizontal line L1 that indicates the behavior of the vehicle 1 onto the windshield 19, the horizontal line L1 is displayed on the windshield 19. The visual support device 10 moves the horizontal line L1 displayed on the windshield 19 left and right or up and down on the windshield 19, or rotates it, thereby visually presenting the behavior of the vehicle 1 to the occupants using the moving horizontal line L1.

[0022] The vehicle control device 11 is composed of a semiconductor integrated circuit including a central processing unit (CPU), a read only memory (ROM) in which programs and the like are stored, a random access memory (RAM) as a work area, etc. Although a detailed description will be omitted, the vehicle control device 11 drives the vehicle 1 by controlling a drive mechanism 18. In addition to the drive mechanism 18, the vehicle control device 11 also controls the entire vehicle 1, including a braking mechanism 17 that brakes the vehicle 1 and a steering mechanism 16 that turns the vehicle 1.

[0023] The vehicle control device 11 also has a function of communicating with each device provided in the vehicle 1, such as the visual assistance device 10, on-board electronic devices, etc. The vehicle control device 11 transmits and receives various information to and from each of the devices. For example, CAN (Controller Area Network) communication may be used as a communication method between the vehicle control device 11 and each device.

[0024] The sensor group 12 functions as a detection unit that detects the state of the vehicle 1. The sensor group 12 includes a vehicle speed sensor 121, an acceleration sensor 122, an angular velocity sensor 123, a steering angle sensor 124, and an accelerator position sensor (not shown). The vehicle speed sensor 121 detects the speed (vehicle speed) of the vehicle 1. The acceleration sensor 122 detects the acceleration of the vehicle 1. The angular velocity sensor 123 detects the angular velocity of the vehicle 1. The steering angle sensor 124 detects the rotation angle of the steering wheel 13. The accelerator position sensor detects the operation amount (depression amount) of the accelerator pedal 14.

[0025] The steering wheel 13 receives a steering operation by the driver, the accelerator pedal 14 receives an accelerator operation by the driver, and the brake pedal 15 receives a brake operation by the driver.

[0026] The steering mechanism 16 changes the angle of the front wheels relative to the vehicle body, i.e., the traveling direction of the vehicle 1, in accordance with the steering angle of the steering wheel 13 operated by the driver. The braking mechanism 17 changes the braking force in accordance with the amount of depression of the brake pedal 15 operated by the driver. The drive mechanism 18 is configured to include a drive source. The drive mechanism 18 changes the output of the drive source in accordance with the amount of depression of the accelerator pedal 14 operated by the driver.

[0027] The windshield 19 is provided in front of the vehicle 1. The windshield 19 is configured with a panel made of a transparent material such as glass. A horizontal line L1 indicating the behavior of the vehicle 1 is projected and displayed on the windshield 19 by the visual support device 10.

[0028] (3. Hardware configuration of visual support device) The hardware configuration of the visual support device 10 will be described with reference to Fig. 3. Fig. 3 is a block diagram showing the hardware configuration of the visual support device 10.

[0029] As shown in FIG. 3, the visual support device 10 includes one or more processors 100, one or more memories 110, a communication device 120, an input device 130, a projection device 140, and a bus 150.

[0030] The processor 100 is an arithmetic processing unit mounted on a computer. The memory 110 includes a ROM in which programs and the like are stored and a RAM as a work area. The processor 100 controls the visual support device 10 by executing the programs stored in the memory 110. In addition to the programs that control the visual support device 10, the memory 110 also stores various data used by the processor 100 when executing the programs. For example, the memory 110 stores mathematical formulas used to calculate the yaw rate, roll angle, or pitch angle, which will be described later.

[0031] The communication device 120 is a device for communicating with an external device connected by wire or wirelessly to the visual support device 10. For example, the visual support device 10 communicates with the vehicle 1.

[0032] The input device 130 is a device used by a user (e.g., a passenger) to turn on / off the power of the visual support device 10, turn on / off the display of the horizontal line L1 that indicates the behavior of the vehicle 1, and input information to the visual support device 10. The input device 130 includes, for example, a touch sensor, a remote controller, a button, a switch, or a dial. For example, when the input device 130 receives an input operation from the user (e.g., an operation to instruct the start of display of the horizontal line L1), it transmits an input signal corresponding to the input operation to the processor 100.

[0033] The projection device 140 is an example of an output device for outputting information, images, audio, etc. to the outside of the visual support device 10. The projection device 140 displays information such as text, figures, and images by emitting laser light so as to scan the inner surface of the windshield 19. For example, the projection device 140 displays a horizontal line L1 indicating the behavior of the vehicle 1 on the windshield 19. In this case, the projection device 140 is an example of a display unit that displays an object for visual support on the windshield 19. Note that, although the present embodiment has been described as an example of a configuration in which the visual support device 10 includes the projection device 140 as an output device, this is not limiting. For example, in addition to the projection device 140, the visual support device 10 may further include an audio output device that outputs audio representing various information.

[0034] The processor 100, memory 110, communication device 120, input device 130, and projection device 140 are interconnected by a bus 150. This allows various types of information to be transmitted and received between these devices.

[0035] (3.1. Functional configuration of visual support device) The functional configuration of the visual support device 10 will be described with reference to Fig. 4. Fig. 4 is a block diagram showing the functional configuration of the visual support device 10. The processor 100 of the visual support device 10 executes a program stored in the memory 110, thereby functioning as an acquisition unit 100A, a calculation unit 100B, and a display control unit 100C.

[0036] The acquisition unit 100A acquires the steering angle of the steering wheel 13, the vehicle speed of the vehicle 1, and the accelerator operation amount from the traveling vehicle 1. For example, the acquisition unit 100A receives, via the communication device 120, the detection value (waveform data of the steering angle) of the steering angle sensor 124 of the vehicle 1 as the steering angle of the steering wheel 13. The acquisition unit 100A also receives, via the communication device 120, the detection value (waveform data of the vehicle speed) of the vehicle speed sensor 121 of the vehicle 1 as the vehicle speed. The acquisition unit 100A also acquires, via the communication device 120, the detection value (waveform data of the operation amount of the accelerator pedal 14) of an accelerator position sensor (not shown) included in the sensor group of the vehicle 1 as the accelerator operation amount.

[0037] The calculation unit 100B is an example of a control unit that controls the display of visual support objects. For example, the calculation unit 100B calculates a yaw rate γ and a roll angle Φ based on the steering angle of the steering wheel 13, the vehicle speed of the vehicle 1, and specifications of the vehicle 1. The calculation unit 100B also calculates a pitch angle θ based on the steering angle of the steering wheel 13, the vehicle speed of the vehicle 1, the accelerator operation amount, and specifications of the vehicle 1. For example, mathematical formulas for calculating the yaw rate γ, the roll angle Φ, and the pitch angle θ are pre-stored in the memory 110. The calculation unit 100B calculates the yaw rate γ and the roll angle Φ based on the mathematical formulas for calculating the yaw rate γ and the roll angle Φ and the steering angle of the steering wheel 13 and the vehicle speed acquired by the acquisition unit 100A. The calculation unit 100B also calculates the pitch angle θ based on the mathematical formula for calculating the pitch angle θ and the steering angle of the steering wheel 13, the vehicle speed, and the accelerator operation amount acquired by the acquisition unit 100A. The methods for calculating the yaw rate γ, the roll angle Φ, and the pitch angle θ will be described in detail later.

[0038] The display control unit 100C is an example of a control unit that controls the display of visual support objects. For example, the display control unit 100C controls the projection device 140 to display a horizontal line L1 indicating the behavior of the vehicle 1 on the windshield 19. A specific example of the horizontal line L1 indicating the behavior of the vehicle 1 will be described below with reference to FIG. 5. FIG. 5 is a diagram showing a specific example of a visual support object that the visual support device 10 displays on the windshield 19. Note that in FIG. 5 and the following, with the windshield 19 as the reference, an axis extending in the width direction (left-right direction) of the windshield 19 is defined as the x-axis, and an axis extending in the up-down direction of the windshield 19 is defined as the y-axis. In FIG. 5, the vehicle 1 is stopped on a horizontal plane, so the x-axis of the windshield 19 is parallel to the pitch axis Y of the vehicle 1. On the other hand, as shown in FIGS. 7B and 8, when the traveling vehicle 1 tilts in the roll direction while turning a curve, the x-axis of the windshield 19 tilts with respect to the pitch axis Y of the vehicle 1.

[0039] 5, the display control unit 100C displays a horizontal line L1 consisting of two straight lines parallel to each other in the vertical direction on the windshield 19. The display control unit 100C moves the horizontal line L1 in the direction of arrow 20 (left and right direction) or in the direction of arrow 21 (up and down direction) on the windshield 19, or rotates it in the direction of arrow 22, depending on the yaw rate γ, roll angle Φ, and pitch angle θ calculated by the calculation unit 100B. In this way, the behavior of the vehicle 1 is shown to the occupants.

[0040] (4. Calculation method for vehicle 1 behavior) As described above, the visual support device 10 calculates the yaw rate γ, roll angle Φ, and pitch angle θ of the vehicle 1 as the behavior of the vehicle 1 while it is traveling. The yaw rate γ [deg / sec] is the rate of change [deg / sec] of the yaw angle when the vehicle 1 is turning, etc. The yaw rate γ represents the rotational angular velocity around a vertical axis (yaw axis Z in FIG. 1) passing through the center of gravity C of the vehicle 1. The yaw angle [deg] refers to the angle between the longitudinal axis of the vehicle 1 (roll axis X in FIG. 1) and a reference axis fixed to the road surface (such as the X axis of a road-fixed coordinate system). The yaw angle indicates the direction of travel of the vehicle 1 relative to the road surface. The roll angle Φ [deg] is the rotational angle around the longitudinal axis (roll axis X in FIG. 1) passing through the center of gravity C of the vehicle 1. The roll angle Φ is calculated using the roll moment as an input and is generated by the suspension roll angle due to suspension deflection and the vertical deflection of the tires. When the vehicle 1 rotates in the roll direction, the occupants' bodies tilt and their line of sight change, so the roll direction rotation of the vehicle 1 is a vehicle behavior that occupants are particularly sensitive to. The pitch angle θ [deg] is the angle of rotation around the left-right axis (pitch axis Y in Figure 1) that passes through the center of gravity C of the vehicle 1.

[0041] The reference state of the vehicle 1 is a state in which the vehicle 1 is horizontal with respect to the ground. For example, when the vehicle 1 is stopped and horizontal with respect to the ground, the angular velocity sensors 123 of the vehicle 1 perform zero point correction of each sensor for measuring vehicle behavior. As a result, for example, the zero points of the angular velocity sensors 123 in the X, Y, and Z axis directions are stored as a state in which the vehicle 1 is horizontal with respect to the ground. In other words, when the detection values ​​of the angular velocity sensors 123 are 0, the vehicle 1 is stopped and horizontal with respect to the ground.

[0042] The vehicle 1 may be in a horizontal state when it is stopped before it starts moving. This allows the reference state to be a state in which the vehicle 1 is slightly tilted in the front-to-back or left-to-right direction relative to the ground due to the imbalance of the riding positions of the occupants in the vehicle 1, the amount of luggage being loaded, etc. As a result, if the reference state is a state in which the vehicle 1 is horizontal relative to the ground, it is possible to prevent tilting of the vehicle 1 from being detected all the time.

[0043] Below, we will explain how the calculation unit 100B of the visual support device 10 calculates the yaw rate γ and the roll angle Φ based on the steering angle of the steering wheel 13, the vehicle speed of the vehicle 1, and the specifications of the vehicle 1, and how it calculates the pitch angle θ based on the steering angle δ of the steering wheel 13, the vehicle speed of the vehicle 1, the accelerator operation amount, and the specifications of the vehicle 1.

[0044] (4.1. Yaw rate calculation method) First, before calculating the yaw rate γ, the calculation unit 100B calculates a stability factor A based on the specifications of the vehicle 1. The stability factor A is calculated based on the steering angle δ of the steering wheel 13. h It is a characteristic value that indicates the steering characteristics of the vehicle 1 when the vehicle 1 is making a steady circular turn with a constant (steering wheel angle). More specifically, the calculation unit 100B calculates the stability factor A according to the following formula (1).

number

[0045] l: Wheelbase lf: Distance from the front wheel to the center of gravity lr: distance from rear wheel to center of gravity m=mr+mf: Vehicle mass mr: Rear wheel mass mf: Front wheel mass A: Stability factor Kf: Front wheel cornering power Kr: Rear wheel cornering power γ: Yaw rate δ: Actual steering angle V:Vehicle speed Ay: Lateral acceleration

[0046] In the above formula (1), "l" indicates the wheelbase. "m" indicates the vehicle mass. The vehicle mass m is the mass of vehicle 1. The vehicle mass m is the sum of the rear wheel mass mr and the front wheel mass mf. "lf" indicates the distance from the front wheels to the center of gravity C of vehicle 1. "lr" indicates the distance from the rear wheels to the center of gravity C of vehicle 1. "Kf" indicates the front wheel cornering power. "Kr" indicates the rear wheel cornering power.

[0047] The elements l, m, mr, mf, lf, lr, Kf, Kr, etc. used in the above formula (1) are vehicle specifications. The vehicle specifications are fixed values ​​that are uniquely determined for each type of vehicle 1. Therefore, the stability factor A may be calculated in advance from the values ​​of these vehicle specifications and stored in memory 110.

[0048] Next, the calculation unit 100B calculates the yaw rate γ using the stability factor A calculated by the above formula (1). More specifically, the calculation unit 100B calculates the yaw rate γ according to the following formula (2).

number

[0049] In the above formula (2), "V" indicates the speed of the vehicle 1. For example, the vehicle speed V is a value detected by the vehicle speed sensor 121 of the vehicle 1. Furthermore, "δ" indicates the actual steering angle. Steering angle δ h is the angle of the steering shaft (steering wheel angle) given by turning the steering wheel 13. The actual steering angle δ is the angle actually given to the front tires (front wheels). The actual steering angle δ is the angle given by the steering angle δ h (steering wheel angle) multiplied by gear ratio k (δ = k × δ h The gear ratio k is the gear ratio of the gear that transmits the rotation of the steering shaft to the rotation of the rotation shaft of the front tires (front wheels). For example, the actual steering angle δ is the steering angle δ of the steering wheel 13 detected by the steering angle sensor 124 of the vehicle 1. h is multiplied by the gear ratio k.

[0050] For example, the steering angle sensor 124 detects a steering angle δ in a neutral state where the steering wheel 13 is not being operated. h In this case, when the steering wheel 13 is operated in the forward direction (for example, clockwise) from the neutral state, the steering angle sensor 124 detects the steering angle δ of the operation. h When the steering wheel 13 is operated in a negative direction (for example, counterclockwise) from the neutral state, the steering angle sensor 124 detects the steering angle δ h is detected as a negative value.

[0051] The yaw rate γ calculated according to the above formula (2) is positive or negative depending on the turning direction of the vehicle 1. For example, when the vehicle 1 turns right from the reference state (turns in the direction of arrow Y1 in FIG. 1), the yaw rate γ is calculated as a positive value. When the vehicle 1 turns left from the reference state (turns in the direction of arrow Y2 in FIG. 1), the yaw rate γ is calculated as a negative value.

[0052] Next, the calculation unit 100B calculates the lateral acceleration Ay using the yaw rate γ calculated by the above equation (2). The lateral acceleration Ay is the acceleration in the left-right direction (the Y-axis direction in FIG. 1) that occurs when the vehicle 1 turns. More specifically, the calculation unit 100B calculates the lateral acceleration Ay according to the following equation (3).

number

[0053] As shown in the above equation (3), the lateral acceleration Ay is calculated by multiplying the yaw rate γ by the vehicle speed V. Therefore, when the vehicle 1 turns right and the yaw rate γ is calculated as a positive value, the lateral acceleration Ay is also calculated as a positive value. When the vehicle 1 turns left and the yaw rate γ is calculated as a negative value, the lateral acceleration Ay is also calculated as a negative value.

[0054] (4.2. Calculation method of roll angle Φ) The calculation unit 100B of the visual support device 10 calculates the steering angle δ of the steering wheel 13. hA method for calculating the roll angle Φ based on the vehicle speed V of the vehicle 1 and the specifications of the vehicle 1 will be described.

[0055] The calculation unit 100B calculates the roll angle Φ according to the following equation (4).

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[0056] In the above formula (4), "h" represents the roll arm length, which is the distance from the vehicle's center of gravity to the roll center height. "kf" represents the front wheel roll stiffness. "kr" represents the rear wheel roll stiffness. These values ​​are specifications of vehicle 1. "g" represents the gravitational acceleration. According to the above formula (4), the roll angle Φ increases or decreases linearly depending on the value of the lateral acceleration Ay.

[0057] For example, if the vehicle 1 rotates in the positive direction around the roll axis X from the reference state (tilts in the direction of arrow R1 in FIG. 1), the roll angle Φ is calculated as a positive value. If the vehicle 1 rotates in the negative direction around the roll axis X from the reference state (tilts in the direction of arrow R2 in FIG. 1), the roll angle Φ is calculated as a negative value.

[0058] (4.3. Calculation method of pitch angle θ) The calculation unit 100B of the visual support device 10 calculates the steering angle δ of the steering wheel 13. h Next, a method for calculating the pitch angle θ based on the vehicle speed V of the vehicle 1, the accelerator operation amount, and the specifications of the vehicle 1 will be described.

[0059] First, the calculation unit 100B calculates the steering angle δ of the steering wheel 13 according to the following equation (5): h The pitch angle θ1 caused by the fluctuation (steering) of the steering angle θ1 is calculated.

number

[0060] Φ: Roll angle θ: Pitch angle l: Wheelbase m=mr+mf: Vehicle mass mr: Rear wheel mass mf: Front wheel mass h RCf : Front wheel roll center height h RCr : Rear wheel roll center height h: Roll arm length K Sf , K Sr : Wheel rate kf: Front wheel roll stiffness kr: rear wheel roll stiffness Kx:kf+kr-h·m·g d: tread g:Gravity acceleration q: Front-to-rear load transfer ratio Ay: Lateral acceleration

[0061] In the above formula (5), "h RCf " indicates the height of the front wheel roll center. RCr " indicates the rear wheel roll center height. Sf " indicates the front wheel rate. "h" is the roll arm length, which indicates the distance from the center of gravity C of the vehicle 1 to the roll center height. "K Sr " indicates the rear wheel rate. "kf" indicates the front wheel roll stiffness, and "Kr" indicates the rear wheel roll stiffness. In the above formula (5), "Kx" is "kf + kr - h·m·g". "d" indicates the tread. "q" indicates the front / rear load transfer distribution ratio. The front / rear load transfer distribution ratio q is the proportion of the load transfer amount of the front wheels in the lateral load transfer Fzs (total) in the roll moment.

[0062] The elements l, m, mr, mf, and h used in the above formulas (2) to (5) are RCf , h RCr , h, K Sf , K. Sr , kf, kr, Kx, d, and q are examples of the vehicle specifications.

[0063] Furthermore, calculation unit 100B calculates pitch angle θ2 that occurs due to acceleration or deceleration of vehicle 1. Specifically, calculation unit 100B first calculates the driving force of vehicle 1 based on the accelerator operation amount acquired by acquisition unit 100A. For example, calculation unit 100B stores data in memory 110 that associates the accelerator operation amount with the driving force of vehicle 1, and calculates the driving force of vehicle 1 based on the data. Note that calculation unit 100B may store in memory 110 a mathematical formula for calculating the driving force of vehicle 1 from the accelerator operation amount, and calculate the driving force of vehicle 1 using the mathematical formula.

[0064] Next, calculation unit 100B calculates, based on the driving force of vehicle 1, longitudinal force Fxf generated on the front wheels and longitudinal force Fxr generated on the rear wheels when vehicle 1 accelerates or decelerates. Here, longitudinal force refers to the longitudinal friction force generated between the road surface and the tires (front wheels or rear wheels), i.e., braking / driving force. Longitudinal force includes front force and rear force. Front force is the friction force acting in the forward direction from the tires (front wheels or rear wheels) to the road surface when vehicle 1 decelerates. Rear force is the friction force acting in the rear direction from the tires (front wheels or rear wheels) to the road surface when vehicle 1 accelerates. When longitudinal forces Fxf and Fxr are rear forces (when accelerating), the values ​​of longitudinal forces Fxr and Fxf are negative values. On the other hand, when longitudinal forces Fxf and Fxr are front forces (when decelerating), the values ​​of longitudinal forces Fxr and Fxf are positive values.

[0065] The calculation unit 100B calculates the pitch angle θ2 caused by acceleration or deceleration of the vehicle 1 from Fxf and Fxr according to the following equation (6).

number

[0066] Fxf: Front wheel longitudinal force Fxr: Rear wheel longitudinal force Kp: Pitch stiffness hg: Vehicle center of gravity height

[0067] In the above equation (6), "Fxf" indicates the longitudinal force of the front wheels when the vehicle 1 accelerates or decelerates, and is determined by the accelerator operation amount. "Fxr" indicates the longitudinal force of the rear wheels when the vehicle 1 accelerates or decelerates, and is determined by the accelerator operation amount. "Kp" indicates the pitch stiffness, which is the stiffness of the body of the vehicle 1 around the pitch axis Y. Since the pitch stiffness Kp is a basic characteristic of the vehicle 1, it is determined in advance as a design value or an experimental value. "hg" indicates the height from the contact patch between the road surface and the tire (front wheel or rear wheel) to the center of gravity C of the vehicle 1. Note that the elements Kp and hg used in the above equation (6) are examples of the vehicle specifications.

[0068] Then, the calculation unit 100B calculates the pitch angle θ by adding the pitch angle θ1 generated by steering the vehicle 1 and the pitch angle θ2 generated by accelerating or decelerating the vehicle 1, as shown in the following equation (7).

number

[0069] When the vehicle 1 rotates in the positive direction around the pitch axis Y from the reference state (tilts in the direction of arrow P1 in FIG. 1), the pitch angle θ is calculated as a positive value. When the vehicle 1 rotates in the negative direction around the pitch axis Y from the reference state (tilts in the direction of arrow P2 in FIG. 1), the pitch angle θ is calculated as a negative value.

[0070] (5. Filtering process) The calculation unit 100B of the visual support device 10 performs filtering processing to extract data of predetermined frequency components from the time-series data of the yaw rate γ, roll angle Φ, and pitch angle θ calculated according to the above equations (1) to (7). The filtering processing performed on the time-series data of the yaw rate γ, roll angle Φ, and pitch angle θ calculated by the calculation unit 100B will be described below with reference to Fig. 6. Fig. 6 is a Bode diagram for explaining the yawing resonance frequency of the vehicle 1.

[0071] As described above, the steering angle sensor 124 provided in the vehicle 1 detects the steering angle δ hThe steering angle sensor 124 detects the rotation angle of the steering wheel 13 from the neutral state as a function of the steering angle δ. The steering angle sensor 124 detects not only the low-frequency rotation angle resulting from the steering operation of the steering wheel 13 by the driver, but also the high-frequency rotation angle resulting from road vibrations that the vehicle 1 receives from the road surface while traveling. Therefore, if the yaw rate γ, roll angle Φ, and pitch angle θ are calculated based on the detection values ​​of the steering angle sensor 124 and the horizontal line displayed on the windshield 19 is moved or rotated based on the yaw rate γ, roll angle Φ, and pitch angle θ, the horizontal line will always be in a state of slight vibration in accordance with the high-frequency road vibrations. This may cause discomfort to the occupants or induce motion sickness. Therefore, the visual support device 10 according to this embodiment detects the high-frequency steering angle δ resulting from road vibrations. h and excludes the fluctuation of the low-frequency steering angle δ resulting from the operation of the steering wheel 13 by the driver. h In order to preferably extract only the calculated yaw rate γ, roll angle Φ, and pitch angle θ, a filtering process is performed.

[0072] In general vehicles, the yaw resonance frequency for steering operation (rotation of the steering wheel 13) is set to, for example, a value between 1.0 Hz and 2.0 Hz. This is because, although the speed of steering operation by the driver varies from person to person, the yaw resonance frequency for steering operation is generally about 0.2 Hz to 1 Hz, and even in situations where the steering operation is fast, it is set to 2.0 Hz or less. Therefore, the calculation unit 100B performs filtering processing using a low-pass filter that extracts frequency components of 2 Hz or less. More preferably, the filtering processing is performed using a low-pass filter that extracts frequency components of the resonance frequency of the vehicle 1 or less (for example, 1.5 Hz or less). This makes it possible to exclude the influence of road vibrations and preferably detect only the operation of the steering wheel 13 by the driver.

[0073] The above-mentioned resonant frequency of the vehicle 1 is determined by the vehicle specifications. The resonant frequency of the vehicle 1 is, for example, the peak value of the yaw resonant frequency of the vehicle 1. When the gain of the yaw rate γ with respect to the steering wheel angle in the vehicle 1 has the frequency characteristics shown in FIG. 6, the peak value of the yaw resonant frequency is 1.4 Hz. Therefore, the resonant frequency of the vehicle 1 is 1.4 Hz. In this case, the vehicle 1 uses a low-pass filter in the filtering process that extracts frequency components of 1.4 Hz or less. This makes it possible to extract the yaw rate γ, roll angle Φ, and pitch angle θ of the vehicle 1 in response to the operation of the steering wheel 13 by the driver.

[0074] (6. Display of horizontal lines while driving) 7A and 7B are diagrams illustrating an outline of the movement of the horizontal line L1 displayed on the windshield 19 by the visual support device 10 according to this embodiment. Fig. 7A is a diagram illustrating the horizontal line L1 displayed on the windshield 19 when the vehicle 1 is in a reference state. Fig. 7B is a diagram illustrating the movement and rotation of the horizontal line L1 when the vehicle 1 makes a right turn (rotates in the direction of arrow Y1 in Fig. 1) from the reference state.

[0075] When the vehicle 1 is in the reference state, for example, the visual support device 10 displays a horizontal line L1 in the approximate center of the windshield 19, as shown in FIG. 7A. Hereinafter, the position where the horizontal line L1, which indicates the reference state of the vehicle 1, is displayed is referred to as the reference position. When the steering wheel 13 is operated, the visual support device 10 moves or rotates the horizontal line L1 from the reference position according to the yaw rate γ, roll angle Φ, and pitch angle θ calculated by the calculation unit 100B. For example, as shown in FIG. 7B, when the steering wheel 13 is operated rightward while the vehicle 1 is traveling, centrifugal force causes the vehicle 1 to rotate around the roll axis X in the R2 direction (see FIG. 1) by the roll angle Φ and tilt to the left. Therefore, when the steering wheel 13 is operated rightward, the visual support device 10 moves the horizontal line L1 diagonally upward to the right of the windshield 19. This allows the occupant's line of sight to move in the turning direction (rightward) of the vehicle 1, thereby reducing the occurrence of motion sickness in the occupant. Furthermore, when the steering wheel 13 is turned rightward, the visual assistance device 10 rotates the horizontal line L1 by a rotation angle α (= roll angle Φ) in the direction (R1 direction) opposite to the rotation direction (R2 direction) of the vehicle 1 about the roll axis X. As a result, even if the vehicle 1 rotates (rolls) about the roll axis X while traveling, the horizontal line L1 displayed on the windshield 19 is always displayed horizontally relative to the horizontal plane. Therefore, the horizontal line L1 allows the occupant to visually recognize the horizontal direction relative to the ground, and the occurrence of motion sickness in the occupant is suppressed.

[0076] (6.1. How to calculate the movement of the horizontal line L1) Next, a method for calculating the movement amount L and rotation angle α of the horizontal line L1 by the visual support device 10 according to this embodiment will be described with reference to Fig. 8. Fig. 8 is a diagram illustrating the movement amount L and rotation angle α of the visual support object (horizontal line) displayed on the front window 19 by the visual support device 10. Fig. 8 shows the movement and rotation of the horizontal line L1 when the steering wheel 13 is operated rightward.

[0077] As described above, when the steering wheel 13 is operated while the vehicle 1 is traveling, the visual support device 10 moves or rotates the horizontal line L1 from a reference position on the windshield 19 in accordance with the yaw rate γ, roll angle Φ, and pitch angle θ calculated by the calculation unit 100B. At this time, the visual support device 10 calculates the movement amount L and rotation angle α of the horizontal line L1 in accordance with the yaw rate γ, roll angle Φ, and pitch angle θ.

[0078] For example, the calculation unit 100B of the visual support device 10 calculates the movement amount Lx of the horizontal line L1 in the x-axis direction based on the yaw rate γ' after filtering. The movement amount Lx is the length in the x-axis direction from the center point 23 of the horizontal line L1 at the reference position to the center point 26 of the horizontal line L1 after the movement. For example, the relationship between the movement amount Lx and the yaw rate γ' is expressed by a linear function, Lx = Kx · γ' (Kx ≧ 0). That is, the yaw rate γ' and the movement amount Lx are proportional to each other, and the larger the absolute value of the yaw rate γ', the larger the absolute value of the movement amount Lx. As described above, when the steering wheel 13 is turned rightward, the vehicle 1 tilts leftward about the roll axis X, and the yaw rate γ' is calculated as a positive value, so the movement amount Lx is also calculated as a positive value. On the other hand, when the steering wheel 13 is turned leftward, the vehicle 1 tilts rightward about the roll axis X, and the yaw rate γ' is calculated as a negative value, so the movement amount Lx is also calculated as a negative value.

[0079] The coefficient Kx is a fixed value that is set appropriately for each vehicle model of the vehicle 1, for example. For example, when the maximum value Lx_max of the movement amount Lx is calculated as the product of the maximum value γ'_max of the expected yaw rate γ' and the coefficient Kx, it is preferable to set the value of the coefficient Kx so that the horizontal line L1 moved in the left-right direction by the maximum value Lx_max fits within the windshield 19. It is also preferable that the coefficient Kx can be adjusted appropriately by the occupant of the vehicle 1 according to their own preferences. For example, by setting the value of the coefficient Kx to a small value, the range of movement of the horizontal line L1 in the left-right direction can be set to a narrower range. On the other hand, by setting the value of the coefficient Kx to a large value, the range of movement of the horizontal line L1 in the left-right direction can be set to a larger range. By adjusting the movement amount Ly according to the occupant's preferences, the horizontal line L1 can be moved in the left-right direction within an appropriate range according to the occupant's preferences.

[0080] The calculation unit 100B of the visual support device 10 also calculates the amount of movement Ly of the horizontal line L1 in the y-axis direction based on the pitch angle θ' after filtering. The amount of movement Ly is the length in the y-axis direction from the center point 23 of the horizontal line L1 at the reference position to the center point 26 of the horizontal line L1 after the movement. For example, the relationship between the amount of movement Ly and the pitch angle θ' is expressed as a linear function: Lx = Ky · θ' (Ky ≧ 0). That is, the pitch angle θ' and the amount of movement Ly are proportional to each other, and the greater the absolute value of the pitch angle θ', the greater the absolute value of the amount of movement Ly. For example, when the vehicle 1 is turning a corner, if the steering wheel 13 is operated to the right and the vehicle 1 decelerates, the vehicle 1 will tilt to the left about the roll axis X and forward about the pitch axis Y. In this case, the pitch angle θ' is calculated as a positive value, and the amount of movement Ly is also calculated as a positive value. As a result, the horizontal line L1 moves upward in the y-axis direction.

[0081] The coefficient Ky is a fixed value that is set appropriately for each vehicle model of the vehicle 1, for example. For example, when the maximum value Ly_max of the movement amount Ly is calculated as the product of the maximum value θ'_max of the expected pitch angle θ' and the coefficient Ky, it is preferable to set the value of the coefficient Ky so that the horizontal line L1 moved vertically by the maximum value Ly_max fits within the windshield 19. It is also preferable that the coefficient Ky be adjustable appropriately by the occupant of the vehicle 1 according to their own preferences. For example, by setting the value of the coefficient Ky to a small value, the vertical movement range of the horizontal line L1 can be set to a narrower range. On the other hand, by setting the value of the coefficient Ky to a large value, the vertical movement range of the horizontal line L1 can be set to a larger range. By adjusting the movement amount Ly according to the occupant's preferences, the horizontal line L1 can be moved vertically within an appropriate range that suits the occupant's preferences.

[0082] The calculation unit 100B of the visual support device 10 calculates the movement amount L of the horizontal line L1 based on the calculated movement amount Lx in the left-right direction (x-axis direction) and the movement amount Ly in the up-down direction (y-axis direction). As shown in FIG. 8, a right-angled triangle is formed by the movement amount L, the movement amount Lx in the x-axis direction, and the movement amount Ly in the y-axis direction. Since the movement amount L corresponds to the hypotenuse of the right-angled triangle, L 2 =Lx 2 +Ly 2 Therefore, the movement amount L is calculated based on the movement amount Lx and the movement amount Ly. Note that, if the movement amounts Lx and Ly are calculated, the movement amount L does not necessarily have to be calculated.

[0083] The calculation unit 100B of the visual support device 10 also calculates the rotation angle α of the horizontal line L1 based on the roll angle Φ' after filtering. The rotation angle α may be, for example, the same value as the roll angle Φ'. For example, when the roll angle Φ' is a positive value, the vehicle 1 rotates in the positive direction around the roll axis X from the reference state (tilts in the direction of arrow R1 in FIG. 1), so the visual support device 10 rotates the horizontal line L1 to the left by the rotation angle α. On the other hand, when the roll angle Φ' is a negative value, the vehicle 1 rotates in the negative direction around the roll axis X from the reference state (tilts in the direction of arrow R2 in FIG. 1), as shown in FIGS. 7B and 8, so the horizontal line L1 on the windshield 19 is rotated to the right by the rotation angle α. In this way, the horizontal line L1 on the windshield 19 is rotated left and right by the rotation angle α corresponding to the roll angle Φ'. As a result, the horizontal line L1 displayed on the windshield 19 always remains parallel to the horizontal plane. Therefore, by visually checking the horizontal line L1 that maintains the horizontal state, the occupant can predict the tilting movement of the vehicle 1 in the roll direction while traveling, thereby suppressing motion sickness.

[0084] (6. Display control process of horizontal lines while driving) Next, the flow of the display control process in which the visual support device 10 displays a horizontal line L1 indicating the behavior of the vehicle 1 on the front window 19 while the vehicle 1 is moving will be described with reference to Fig. 9. Fig. 9 is a flowchart illustrating the flow of the display control process executed by the visual support device 10.

[0085] As shown in FIG. 9, the display control process includes steps S100 to S115.

[0086] First, in step S100, the visual support device 10 receives an input operation from the occupant to start displaying a horizontal line L1 on the windshield 19. This input operation may be, for example, an operation by the occupant to set the motion sickness prevention mode to ON for the visual support device 10. When the motion sickness prevention mode is set to ON, the visual support device 10 displays the horizontal line L1 on the windshield 19. On the other hand, when the motion sickness prevention mode is set to OFF, the visual support device 10 does not display the horizontal line L1 on the windshield 19.

[0087] Next, in step S101, the visual support device 10 displays a horizontal line L1 on the windshield 19. For example, as shown in FIG. 7A, the visual support device 10 displays a horizontal line L1 indicating the reference state of the vehicle 1 on the windshield 19. The position at which the horizontal line L1 is displayed on the windshield 19 is, for example, approximately the center of the windshield 19.

[0088] The position where the horizontal line L1 is displayed may be arbitrarily set by the occupant, for example. If the only occupant is the driver, the horizontal line L1 may be displayed at a position on the windshield 19 that is within the driver's line of sight. Furthermore, if the horizontal line L1 is to be displayed only for a specific occupant, it may be displayed at a position on the windshield 19 that is visible from the seating position of the specific occupant.

[0089] Next, in step S102, the visual support device 10 receives the steering angle δ of the steering wheel 13 from the vehicle 1. h For example, the steering angle sensor 124 of the vehicle 1 receives information indicating the steering angle δ of the steering wheel 13. h Further, a vehicle speed sensor 121 of the vehicle 1 detects the vehicle speed V of the vehicle 1. Further, an accelerator position sensor (not shown) detects the accelerator operation amount. The visual support device 10 receives the steering angle δ of the steering wheel 13 from the vehicle 1 via the communication device 120. h The vehicle speed V and accelerator operation amount are received.

[0090] Next, in step S103, the visual support device 10 receives the steering angle δ of the steering wheel 13 received in step S102. h and the vehicle speed V. The visual support device 10 calculates the yaw rate γ of the vehicle 1 according to, for example, the above equations (1) and (2).

[0091] Next, in step S104, the visual support device 10 performs a filtering process on the yaw rate γ calculated in step S103. Specifically, the visual support device 10 outputs time-series data of the calculated yaw rate γ to a low-pass filter that extracts frequency components equal to or lower than the peak value of the yaw resonance frequency of the vehicle 1. The low-pass filter removes noise components such as road vibrations from the yaw rate γ calculated in step S103, and extracts the component of the yaw rate γ' of the vehicle 1 that corresponds to the steering operation by the driver.

[0092] Next, in step S105, the visual support device 10 calculates the movement amount Lx of the horizontal line L1 based on the yaw rate γ' extracted in step S104. For example, as described above, the movement amount Ly is calculated by multiplying the yaw rate γ' by the coefficient Kx.

[0093] Next, in step S106, the visual support device 10 receives the steering angle δ of the steering wheel 13 received in step S102. h The visual support device 10 calculates the pitch angle θ based on the vehicle speed V and the accelerator operation amount. For example, the visual support device 10 calculates the lateral acceleration Ay of the vehicle 1 according to the above equation (3), and calculates the pitch angle θ according to the above equations (5) to (7).

[0094] Next, in step S107, the visual support device 10 performs a filtering process on the pitch angle θ calculated in step S106. Specifically, the visual support device 10 outputs time-series data of the calculated pitch angle θ to a low-pass filter that extracts frequency components equal to or lower than the peak value of the yawing resonance frequency of the vehicle 1. The low-pass filter removes noise components such as road vibrations from the pitch angle θ calculated in step S106, and extracts the components of the pitch angle θ' of the vehicle 1 caused by the driver's steering operation and accelerator operation.

[0095] Next, in step S108, the visual support device 10 calculates the movement amount Ly of the horizontal line L1 based on the pitch angle θ' extracted in step S107. As described above, the movement amount Ly is the movement amount of the horizontal line L1 in the y-axis direction on the windshield 19. For example, the movement amount Ly is calculated according to the pitch angle θ' within the movement range of the horizontal line L1.

[0096] Next, in step S109, the visual support device 10 calculates the movement amount L of the horizontal line L1. For example, as shown in Fig. 8, the movement amount L is calculated from the movement amount Lx in the x-axis direction and the movement amount Ly in the y-axis direction.

[0097] Next, in step S110, the visual support device 10 receives the steering angle δ of the steering wheel 13 received in step S102. h and the vehicle speed V. The visual support device 10 calculates the lateral acceleration Ay of the vehicle 1 according to, for example, the above formula (3), and calculates the roll angle Φ according to the above formula (4).

[0098] Next, in step S111, the visual support device 10 performs a filtering process on the roll angle Φ calculated in step S110. Specifically, the visual support device 10 outputs time-series data of the calculated roll angle Φ to a low-pass filter that extracts frequency components equal to or lower than the peak value of the yawing resonance frequency of the vehicle 1. The low-pass filter removes noise components such as road vibrations from the roll angle Φ calculated in step S110, and extracts the component of the roll angle Φ' of the vehicle 1 that corresponds to the steering operation by the driver.

[0099] Next, in step S112, the visual support device 10 calculates the rotation angle α of the horizontal line L1 based on the roll angle Φ′ extracted in step S111. For example, the rotation angle α may be the same value as the roll angle Φ calculated by the above equation (4).

[0100] Next, in step S113, the visual support device 10 moves or rotates the horizontal line L1 on the windshield 19. For example, as shown in FIG. 7B, the visual support device 10 moves the horizontal line L1 from the reference position according to the movement amount L calculated in step S109. The visual support device 10 also rotates the horizontal line L1 by a rotation angle α. The amount of movement Lx of the moved horizontal line L1 in the x-axis direction can indicate the degree of change in angular velocity of the turning motion of the vehicle 1 about the yaw axis Z. The amount of movement Ly in the y-axis direction can indicate the degree of tilting motion of the vehicle 1 in the forward / backward direction about the pitch axis Y. The rotation angle α of the horizontal line L1 can indicate the degree of tilting motion of the vehicle 1 in the left / right direction about the roll axis X.

[0101] Next, in step S114, the visual support device 10 determines whether or not an input operation for ending the display of the horizontal line L1 on the windshield 19 has been performed (for example, motion sickness prevention mode OFF).

[0102] If it is determined in step S114 that the motion sickness prevention mode OFF has been input (YES in step S114), the operation proceeds to step S115. Note that if it is determined in step S114 that the motion sickness prevention mode OFF has not been input (NO in step S114), the operation returns to step S101, and the display operation of the horizontal line L1 described above continues (S101 to S113).

[0103] Next, in step S115, the visual support device 10 ends the display of the horizontal line L1 and ends the operation. In this way, the visual support device 10 continues to operate the steering wheel 13 at the steering angle δ until the motion sickness prevention mode OFF is input. h The visual support device 10 calculates the yaw rate γ and roll angle Φ, which represent the behavior of the vehicle 1, based on the vehicle speed V and vehicle specifications. h The pitch angle θ, which represents the behavior of the vehicle 1, is calculated based on the vehicle speed V, the accelerator operation amount, and the vehicle specifications. Then, the horizontal line L1 displayed on the windshield 19 is moved or rotated according to the calculation result.

[0104] In the above display control process, steps S103 to S113 are executed before the behavior of the vehicle 1 is detected by a sensor mounted on the vehicle 1. That is, the horizontal line displayed by the visual support device 10 in step S113 does not indicate the actual behavior of the vehicle 1, but rather predicts the upcoming behavior of the vehicle 1. The sensor mounted on the vehicle 1 and detecting the actual behavior of the vehicle 1 is, for example, an acceleration sensor 122 or an angular velocity sensor 123.

[0105] In a typical vehicle, it takes about a few tenths of a second (for example, 0.25 seconds) from when the steering wheel is operated until a behavior corresponding to that operation occurs. hThe visual support device 10 can calculate the yaw rate γ and roll angle Φ that represent the behavior of the vehicle 1 based on the vehicle speed V and vehicle specifications. h The pitch angle θ, which represents the behavior of the vehicle 1, can be calculated based on the vehicle speed V, the accelerator operation amount, and the vehicle specifications. As a result, after the steering wheel 13 is operated, the yaw rate γ, pitch angle θ, and roll angle Φ, which represent the behavior of the vehicle 1, can be predictively calculated before the behavior corresponding to the operation occurs in the vehicle 1 and is detected by the various sensors, and the horizontal line L1 displayed on the windshield 19 can be moved or rotated according to the yaw rate γ, pitch angle θ, and roll angle Φ.

[0106] As described above, the visual assistance device 10 can present the behavior of the vehicle 1 to the occupant using the movement of the horizontal line L1 displayed on the windshield 19 before the behavior of the vehicle 1 occurs corresponding to the operation of the steering wheel 13. Therefore, even in conditions such as poor visibility, the occupant can predict the behavior of the vehicle 1 by visually checking the movement of the horizontal line L1 displayed on the windshield 19, thereby reducing the occurrence of motion sickness.

[0107] (7. Variations) The visual support object may include a horizontal line, such as the horizontal line L1 formed by two parallel straight lines described above. Another example of a visual support object including a horizontal line will be described below with reference to Fig. 10. Fig. 10 is a diagram showing another example of a visual support object.

[0108] As shown in FIG. 10A, the visual support object L2 may be composed of two parallel lines in the vertical direction and a marker 30. For example, diamond-shaped markers 30 are provided at both ends of the two parallel lines. The markers 30 provided on the two parallel lines are not limited to being diamond-shaped, and may be, for example, dots, circles, stars, etc. Furthermore, the positions of the markers 30 are not limited to being at both ends of the two parallel lines, and may be, for example, in the center of the two parallel lines. By including the markers 30 in the visual support object L2, the visibility of the left-right movement of the visual support object L2 is improved.

[0109] 10B, the visual support object L3 may be composed of two lines parallel to the vertical direction and two lines parallel to the horizontal direction 31 that intersect perpendicularly to the two lines parallel to the vertical direction. For example, the two lines parallel to the horizontal direction 31 intersect at approximately the center of the two lines parallel to the vertical direction. However, the position where the two lines parallel to the horizontal direction 31 intersect with the two lines parallel to the vertical direction is not limited to approximately the center, and may be on either the left or right end side. By including the two lines parallel to the horizontal direction 31 in the visual support object L3, the visibility of the visual support object L2 is improved.

[0110] The visual support objects are not limited to the above-described horizontal line L1, object L2, and object L3. The visual support objects may have any shape and design that makes it easy to visually recognize their movement and rotation on the windshield 19, and may further include, for example, a point or a gauge as long as they include two parallel lines in the vertical direction.

[0111] (8. Summary) As described above, the visual support device 10 according to this embodiment includes a projection device 140 that displays a horizontal line L1 as a visual support object on the windshield 19 of the vehicle 1, and a display control unit 100C that controls the display of the horizontal line L1 by the projection device 140. While the vehicle 1 is traveling, the display control unit 100C calculates the yaw rate γ of the traveling vehicle 1 based on the steering angle of the steering wheel 13 of the vehicle 1 and the vehicle speed V of the vehicle 1, and moves the horizontal line L1 displayed on the windshield 19 by the projection device 140 in the left-right direction of the windshield 19 by an amount corresponding to the yaw rate γ. This allows the visual support device 10 to suppress motion sickness in occupants caused by the turning motion of the vehicle 1.

[0112] In the visual support device 10 according to this embodiment, the visual support object includes a horizontal line, and the display control unit 100C controls the steering angle δ of the steering wheel 13 while the vehicle 1 is traveling. h and vehicle speed V, the pitch angle θ of the vehicle 1 while it is moving is calculated, and the horizontal line L1 displayed on the windshield 19 by the projection device 140 is moved in the up and down direction of the windshield 19 by an amount corresponding to the pitch angle θ. This allows the visual support device 10 to suppress motion sickness in occupants caused by the tilting of the vehicle 1 in the up and down direction.

[0113] In the visual support device 10 according to this embodiment, the visual support object includes a horizontal line, and the display control unit 100C controls the steering angle δ of the steering wheel 13 while the vehicle 1 is traveling. h and vehicle speed V, the roll angle Φ of the vehicle 1 while it is moving is calculated, and the horizontal line L1 displayed on the windshield 19 by the projection device 140 is rotated in the roll direction by a rotation angle α corresponding to the roll angle Φ so that the horizontal line L1 remains parallel to the horizontal plane. This allows the visual support device 10 to suppress motion sickness in occupants caused by tilting the vehicle 1 in the left and right directions.

[0114] In the visual support device 10 according to this embodiment, the display control unit 100C controls the steering angle δ of the steering wheel 13. h and vehicle speed V is detected by a sensor mounted on the vehicle 1, the yaw rate γ is calculated, and the horizontal line L1 displayed on the windshield 19 by the projection device 140 is moved according to the yaw rate γ. This allows the visual support device 10 to predict the behavior of the vehicle 1 and show it to the occupant before the behavior of the vehicle corresponding to the operation of the steering wheel 13 occurs. This makes it possible to more effectively suppress motion sickness in the occupant.

[0115] Furthermore, in the visual support device 10 according to this embodiment, the display control unit 100C performs filtering processing on the yaw rate γ calculated in time series to extract frequency components equal to or lower than the peak value of the yaw resonance frequency of the vehicle 1, and moves the horizontal line L1 displayed on the windshield 19 in the left-right direction of the windshield 19 according to the yaw rate γ' after the filtering processing. This allows the visual support device 10 to detect only the behavior of the vehicle 1 corresponding to the driver's operation of the steering wheel 13. As a result, the onset of motion sickness can be suppressed without causing discomfort to occupants who view the horizontal line L1. [Explanation of symbols]

[0116] 1 vehicle 10 Visual aids 11 Vehicle control device 12 Sensors 13. Steering wheel 14 Accelerator pedal 15 Brake pedal 16 Steering mechanism 17 Braking mechanism 18 Drive mechanism 121 Vehicle speed sensor 122 Acceleration Sensor 123 Angular rate sensor 124 Steering angle sensor 100 processors 110 memory 120 Communication equipment 130 Input Device 140 Projection device 150 Bus 100A Acquisition Section 100B calculation section 100C Display control unit L1, L2, L3 horizontal lines (visual aid objects)

Claims

1. a display unit that displays a visual support object on a front window of the vehicle; a control unit that controls the display of the object by the display unit; Equipped with The control unit calculating a yaw rate of the vehicle while the vehicle is traveling based on a steering angle of a steering wheel of the vehicle and a vehicle speed of the vehicle; A visual support device that moves the object displayed on the windshield by the display unit in the left-right direction of the windshield by an amount corresponding to the yaw rate.

2. the visual aid object includes a horizontal line; The control unit calculating a pitch angle of the vehicle while the vehicle is traveling based on the steering angle and the vehicle speed; The visual support device according to claim 1 , wherein the object displayed on the windshield by the display unit is moved in the up and down direction of the windshield by an amount corresponding to the pitch angle.

3. the visual aid object includes a horizontal line; The control unit the control unit calculates a roll angle of the vehicle while the vehicle is traveling based on the steering angle and the vehicle speed, 2. The visual support device according to claim 1, wherein the horizontal line displayed on the windshield by the display unit is rotated in the roll direction by a rotation angle corresponding to the roll angle so as to maintain the horizontal line parallel to a horizontal plane.

4. 2. The visual assistance device according to claim 1, wherein the control unit calculates the yaw rate before the behavior of the vehicle according to the steering angle and the vehicle speed is detected by a sensor mounted on the vehicle, and moves the object displayed on the windshield by the display unit according to the yaw rate.

5. the control unit performs a filtering process on the yaw rate calculated in time series to extract frequency components equal to or lower than a peak value of a yaw resonance frequency of the vehicle; The visual support device according to claim 1 , wherein the object displayed on the windshield is moved in the left-right direction of the windshield in accordance with the yaw rate after the filtering process.

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