Information transmission device

Abstract

The present invention addresses the problem of providing an information transmission device that improves the predictability of a behavior caused by steering of a vehicle regardless of a seating position in a vehicle cabin. This information transmission device (100) is provided in a vehicle having a steering device (1) that steers wheels (FW), and is configured to be provided with: a parameter detection unit (71) that detects a parameter [sigma] related to the steering amount of the steering device; an excitation unit (240) that excites air around the occupant using a predetermined excitation waveform in accordance with a change in a parameter of the steering device; a rotation center calculation unit that calculates the position of the rotation center (NSP) of the yaw behavior of the vehicle body; and a gain adjustment unit (200, 210) that adjusts the output gain of the excitation waveform in accordance with the relative position between the center of rotation and the seating position of the occupant.

Description

Technical Field

[0001] The present invention relates to an information transmitting device for transmitting information related to the behavior of a vehicle to an occupant of a vehicle. Background Art

[0002] As a technology for providing passengers with information related to the turning behavior of a vehicle such as an automobile by using sound, for example, Patent Document 1 describes a vehicle sound control device, which includes a plurality of speakers arranged so as to surround the passengers when viewed from above, and a controller that controls the sound field in the vehicle cabin by driving the plurality of speakers individually. It is described that when a driving input that changes the vehicle behavior is made, the controller sets a standard yaw rate corresponding to the driving input, detects the actual yaw rate of the vehicle, and rotates the sound field in the vehicle cabin in the direction of the actual change in the vehicle behavior based on the deviation of the actual yaw rate from the standard yaw rate, thereby expressing the change in the turning behavior corresponding to the driving input before the turning behavior actually changes.

[0003] Patent document 2 describes that in a vehicle sound effect generating device that provides the driver with driving information through hearing to enhance the sense of presence of the vehicle turning state, the gains of multiple integer components of the engine speed are set based on the throttle opening, and the sound effect is generated based on the set gains and a storage unit of the multiple integer components. In addition, it is described that when the vehicle is in a turning driving state, the gain of the 4th component among the multiple integer components is set to be larger than the gain in the normal driving state.

[0004] Patent document 3 describes a vehicle seat device that maintains the quietness of the vehicle cabin when the vehicle turns and accurately transmits the turning direction to the seated person. The device has a left speaker that outputs sound from the left side of the head pad and a right speaker that outputs sound from the right side of the head pad. In the case of a left turn, sound is output from the left speaker, and in the case of a right turn, sound is output from the right speaker.

[0005] Prior art literature Patent Literature Patent Document 1: International Publication No. WO2014 / 174839 Patent Document 2: Japanese Patent Application Publication No. 2016-145884 Patent Document 3: Japanese Patent Application Publication No. 2022-119227 Summary of the invention

[0006] Technical issues Since there is a time response delay from the start of vehicle steering to the actual vehicle body behavior, lateral acceleration, yaw rate, roll angle, etc., depending on the conditions of the steering action, the occupants may sometimes feel discomfort and / or uneasiness due to feeling that lateral acceleration is suddenly generated, or that they are unable to properly maintain their bodies.

[0007] On the other hand, measures such as reducing the yaw rate gain with respect to the steering angle of the vehicle to improve the occupant's holding performance by a seat or the like are also considered.

[0008] However, if the yaw rate gain is reduced, the responsiveness of the vehicle will become slow, and the performance and marketability of the vehicle will be impaired. In addition, it is difficult to appropriately respond to occupants of various body shapes using seat-based measures.

[0009] In contrast, as described in the above-mentioned conventional technology, if information related to the behavior of the vehicle can be presented to the occupants through sound information, the occupants' foreseeability of the behavior caused by the turning of the vehicle can be improved, and the sense of abruptness can be suppressed.

[0010] However, the feeling of jerk (acceleration of acceleration) generated instantaneously at the beginning of a vehicle turn differs depending on the seat position in the vehicle cabin, and even if the same information is conveyed to all passengers by sound, an appropriate effect may not be obtained.

[0011] In view of the above-mentioned problems, an object of the present invention is to provide an information transmission device that improves predictability of behavior caused by turning of a vehicle regardless of the seat position in a vehicle cabin.

[0012] Technical Solution In order to solve the above-mentioned problems, an information transmission device of one embodiment of the present invention is characterized in that it is arranged in a vehicle having a steering device for steering wheels, and the information transmission device comprises: a parameter detection unit, which detects parameters related to the steering amount of the steering device; an excitation unit, which uses a predetermined excitation waveform to vibrate the air around the occupant according to changes in the parameters of the steering device; a rotation center calculation unit, which calculates the position of the rotation center of the yaw behavior of the vehicle body; and a gain adjustment unit, which adjusts the output gain of the excitation waveform according to the relative position between the rotation center and the seating position of the occupant.

[0013] According to this, by generating a sound corresponding to the steering amount of the steering device, the occupants can be made to anticipate the occurrence of behavior by the sound at the early stage of steering before the vehicle actually generates lateral acceleration, yaw rate, roll angle, etc.

[0014] This improves the predictability of the vehicle behavior by the occupants, and prevents the occupants from feeling a sense of abruptness regarding the vehicle behavior.

[0015] In addition, by adjusting the output gain of the excitation waveform according to the relative position between the rotation center of the yaw behavior and the seating position of the occupant, information that appropriately reflects the effects of lateral acceleration and jerk on the occupant due to the yaw behavior of the vehicle can be transmitted. This can suppress the deviation between the information transmitted to the occupant by the excitation unit and the lateral acceleration and jerk actually experienced by the occupant, and improve the predictability of the behavior caused by the turning of the vehicle regardless of the seating position in the vehicle.

[0016] In the present invention, the gain adjustment unit may be configured to change the output gain in accordance with a change in the distance between the rotation center and the seating position.

[0017] This reflects that the acceleration and jerk to which the occupant is subjected change in accordance with the increase in the distance from the rotation center to the seated position, thereby enabling appropriate information to be transmitted to the occupant.

[0018] In the present invention, the gain adjustment unit can be configured to reduce the output gain in accordance with an increase in an angle difference, wherein the angle difference is an angle difference between a slip angle of the vehicle body and an angle formed by a straight line connecting the rotation center and the seating position relative to a center line of the vehicle body when viewed from above.

[0019] This makes it possible to appropriately estimate the acceleration or lateral component of the jerk received by the occupant due to the yaw angular acceleration of the vehicle body, and to transmit appropriate information to the occupant.

[0020] In the present invention, a plurality of the seating positions are provided, and a plurality of the excitation units are provided corresponding to the plurality of the seating positions, so that the amplitudes of the excitation waveforms output by the plurality of the excitation units are different according to the relative positions between the rotation center and the seating positions.

[0021] According to this, it is possible to transmit appropriate information corresponding to the seating positions to a plurality of passengers seated at the plurality of seating positions, respectively.

[0022] In the present invention, the excitation waveform may have a main frequency within a frequency band of 100 to 400 Hz.

[0023] This allows the use of Pacinian corpuscles or the like that are highly sensitive in the audible range and highly sensitive in terms of skin sensation, thereby improving the perception of sound and skin sensation of the occupant. Therefore, information can be more reliably transmitted to the occupant.

[0024] Here, more preferably, by setting the main frequency in a frequency band of 150 to 300 Hz, a region where the receptor has better sensitivity can be used, thereby promoting the above-mentioned effect.

[0025] In the present invention, the vehicle may include an automatic driving control unit, the automatic driving control unit may instruct the steering device about the steering amount, and a parameter related to the steering amount of the steering device may be an instruction value of the automatic driving control unit.

[0026] Accordingly, when executing automatic driving control that produces steering angle changes in the steering device without relying on the steering operation of the occupant, by generating a sound corresponding to the change in the steering amount and the positional relationship between the center of rotation and the seating position when the steering based on the automatic driving control starts, the occupant can foresee the occurrence of vehicle behavior accompanied by the generation of lateral acceleration, yaw rate, roll angle, etc., thereby preventing the occupant from feeling abrupt about the vehicle's behavior.

[0027] Technical Effects As described above, according to the present invention, it is possible to provide an information transmission device that improves predictability of behavior caused by turning of a vehicle regardless of the seating position in a vehicle cabin. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 It is a diagram schematically showing the configuration of an electric power steering device of a vehicle having a first embodiment to which the information transmission device of the present invention is applied.

[0029] Figure 2 It is a diagram schematically showing the system configuration of the information transmission device according to the first embodiment.

[0030] Figure 3 It is a diagram schematically showing an example of an excitation waveform in the first embodiment.

[0031] Figure 4 This is a diagram schematically showing the timing of electrical pulses emitted by a receptor when stimulated.

[0032] Figure 5 Graphs showing the distribution of the sensitivity of Pacinian corpuscles and Meissner corpuscles with respect to frequency.

[0033] Figure 6 This is a diagram schematically showing an example of gain adjustment by the first gain adjustment unit according to the first embodiment.

[0034] Figure 7 FIG. 1 is a diagram schematically showing an example of the output history of the microphone in the first embodiment.

[0035] Figure 8 This is a diagram showing an example of the relationship between the sound pressure and frequency of the background noise in the first embodiment.

[0036] Fig. 9 This is a diagram schematically showing an example of gain adjustment by the second gain adjustment unit according to the first embodiment.

[0037] Fig.10 This is a diagram showing an example of the lateral acceleration and lateral jerk of each seat row and the yaw rate of the vehicle body when a vehicle having three rows of seats starts turning.

[0038] Fig.11 Graph showing the resultant force generated by the vehicle body slip angle.

[0039] Fig.12 This is a diagram showing an example of a seat arrangement in a vehicle cabin in the first embodiment.

[0040] Fig.13 FIG. 1 is a diagram schematically showing an example of gain adjustment by the third gain adjustment unit according to the first embodiment.

[0041] Fig.14 FIG. 1 is a diagram schematically showing an example of gain adjustment performed by the fourth gain adjustment unit.

[0042] Fig.15 FIG. 1 is a diagram schematically showing an example of gain adjustment performed by the fifth gain adjustment unit.

[0043] Fig.16 This is a diagram schematically showing an example of the steering force characteristics of a tire corresponding to a load change.

[0044] Fig.17 This is a diagram schematically showing an example of the steering power characteristics of the tire corresponding to the load change.

[0045] Fig.18 It is a diagram schematically showing the configuration of an automatic driving system of a vehicle provided with the information transmission device according to the second embodiment.

[0046] Explanation of symbols

[0047] DETAILED DESCRIPTION

[0048] <First embodiment> Hereinafter, a first embodiment of an information transmission device to which the present invention is applied will be described.

[0049] The information transmission device according to the first embodiment is provided in, for example, a four-wheel vehicle (for example, an automobile such as a passenger car) in which two front wheels are steered (turned).

[0050] The vehicle includes an electric power steering device that applies a steering assist force to a steering device for steering the front wheels using an electric motor.

[0051] Figure 1 It is a diagram schematically showing the configuration of an electric power steering system for a vehicle according to the first embodiment.

[0052] The electric power steering device 1 includes a steering wheel 10 , a steering shaft 20 , an intermediate shaft 21 , a pinion shaft 22 , a rack shaft 30 , a rack housing 40 , a tie rod 50 , a housing 60 , a steering angle sensor 71 , a torque sensor 72 , an actuator unit 80 , an electric power steering control unit (EPS control unit) 90 , and the like.

[0053] The steering wheel 10 is, for example, an annular operation member that is rotated by the driver to input a steering operation.

[0054] The steering wheel 10 is arranged in the vehicle cabin so as to face the driver's seat.

[0055] The steering shaft 20 is a rotating shaft having one end mounted to the steering wheel 10 and transmitting the rotation of the steering wheel 10 to a rack and pinion mechanism that converts the rotation of the steering wheel 10 into a translational motion in the vehicle width direction.

[0056] An intermediate shaft 21 and a pinion shaft 22 are sequentially connected to the end portion of the steering shaft 20 on the opposite side to the steering wheel 10 side.

[0057] Universal joints 23 and 24 capable of transmitting rotation while the shafts are bent are provided between the steering shaft 20 and the intermediate shaft 21 , and between the intermediate shaft 21 and the pinion shaft 22 , respectively.

[0058] A pinion gear for driving the rack shaft 30 so as to mesh with the rack gear 31 of the rack shaft 30 is formed at the front end portion of the pinion shaft 22 .

[0059] The rack shaft 30 is a columnar member disposed such that the longitudinal direction (axial direction) extends along the vehicle width direction.

[0060] The rack shaft 30 is supported so as to be translatably movable in the vehicle width direction relative to the vehicle body.

[0061] A rack gear 31 that meshes with the pinion gear of the pinion shaft 22 is formed at a portion of the rack shaft 30 .

[0062] The rack shaft 30 drives the rack gear 31 by the pinion gear according to the rotation of the steering shaft 20 , so that the rack shaft 30 translates (moves straight) in the vehicle width direction.

[0063] The rack gear 31 is disposed so as to be offset to either the left or right side (usually, the driver's seat side) in the vehicle width direction.

[0064] For example, when the vehicle is a so-called right-hand drive vehicle in which the right front seat is the driver's seat, the rack and pinion 31 is arranged to be offset to the right from the center in the neutral position.

[0065] The rack housing 40 is a substantially cylindrical member that supports and accommodates the rack shaft 30 so as to be relatively displaceable in the vehicle width direction.

[0066] Rack housings 41 are provided at both ends of the rack housing 40 .

[0067] The rack housing 41 is a member that allows the tie rod 50 to be displaced relative to the rack housing 40 and prevents foreign matter such as dust from entering the rack housing 40 .

[0068] The rack housing 41 is formed of a resin material such as an elastomer into a flexible bellows shape.

[0069] The tie rod 50 is a shaft-shaped interlocking member that connects the end of the rack shaft 30 to the knuckle arm 61 of the housing 60 and rotates the housing 60 about the kingpin axis in conjunction with the translational movement of the rack shaft 30 .

[0070] An inner end portion of the tie rod 50 in the vehicle width direction is swingably connected to an end portion of the rack shaft 30 via a ball joint 51 .

[0071] The vehicle width direction outer side end portion of the tie rod 50 is connected to the knuckle arm 61 of the housing 60 via a ball joint 52 .

[0072] The housing (knuckle) 60 is a member that accommodates a hub bearing that supports the front wheel FW so as to be rotatable about the axle.

[0073] The housing 60 has a knuckle arm 61 formed to protrude toward the front side or the rear side with respect to the axle.

[0074] The housing 60 is supported so as to be rotatable about a kingpin axis serving as a predetermined rotation center axis.

[0075] For example, when the front suspension of the vehicle is a MacPherson strut type, the kingpin axis is a virtual axis connecting the bearing center of the strut top bracket and the center of the ball joint connecting the lower part of the housing 60 and the transverse link (lower arm).

[0076] The housing 60 is pushed and pulled in the vehicle width direction by the rack shaft 30 via the tie rod 50 , thereby rotating about the kingpin axis, thereby steering the front wheels FW.

[0077] The steering angle sensor 71 is an angle encoder that detects the rotation angle position of the pinion shaft 22 .

[0078] The output of the steering angle sensor 71 is transmitted to the electric power steering control unit 90 .

[0079] The electric power steering control unit 90 can calculate the steering angle (toe angle change angle accompanying steering) σ of the front wheels FW based on the output of the steering angle sensor 71 .

[0080] The torque sensor 72 is a sensor that detects torque (mainly the steering force of the driver) acting on the pinion shaft 22 .

[0081] The torque sensor 72 is provided at a portion of the pinion shaft 22 that is closer to the intermediate shaft 21 than the actuator unit 80 .

[0082] The output of the torque sensor 72 is transmitted to the electric power steering control unit 90 .

[0083] The actuator unit 80 is a driving device that rotationally drives the pinion shaft 22 to perform power assist during manual driving and steering operation during automatic driving.

[0084] The actuator unit 80 is configured to include a motor 81 , a gear box 82 , and the like.

[0085] The motor 81 is an electric actuator that generates a driving force to be applied to the steering shaft 20 .

[0086] The rotation direction and output torque of the motor 81 are controlled by the electric power steering control unit 90 .

[0087] The gear box 82 includes a reduction gear train that reduces the speed (amplifies the torque) of the rotation output of the motor 81 and transmits the result to the pinion shaft 22 .

[0088] The electric power steering (EPS) control unit 90 is a control device (motor control unit) that provides a current instruction value for controlling the rotation direction and output torque of the motor 81 .

[0089] The electric power steering control unit 90 can be configured as, for example, a microcomputer including an information processing unit such as a CPU, a storage unit such as a RAM and / or a ROM, an input / output interface, and a bus connecting these.

[0090] The electric power steering control unit 90 can obtain information such as the output of the steering angle sensor 71 and the torque sensor 72 , the vehicle's running speed (vehicle speed), and the operating status of other vehicle-mounted electronic devices via an in-vehicle LAN such as a CAN communication system or directly.

[0091] The electric power steering control unit 90 sets a current instruction value to be supplied to the motor 81 based on the torque input direction and the detected torque value of the torque sensor 72 when the vehicle is manually driven.

[0092] The electric power steering control unit 90 includes a power supply device that supplies electric power having a current value and a voltage value corresponding to the current instruction value to the motor 81 via a signal line.

[0093] Figure 2 It is a diagram schematically showing the system configuration of the information transmission device according to the first embodiment.

[0094] The information transmission device 100 vibrates the air around the ears of the occupant using the speaker 240 disposed in the vehicle cabin, thereby notifying the occupant of a precursor to the occurrence of the vehicle behavior using an acoustic signal.

[0095] The information transmission device 100 has a waveform generating unit 110, a differential operation unit 120, a first gain adjustment unit 130, a microphone 140, a sensing value operation unit 150, a second gain adjustment unit 160, a neutral steering point operation unit 170, a yaw rate sensor 180, a vehicle speed sensor 190, a third gain adjustment unit 200, a fourth gain adjustment unit 210, a fifth gain adjustment unit 220, a load sensor 230, a speaker 240, etc.

[0096] The waveform generation unit 110 generates an excitation waveform which is a waveform of an acoustic signal generated by the speaker 240 .

[0097] Figure 3 It is a diagram schematically showing an example of an excitation waveform in the first embodiment.

[0098] exist Figure 3 In the figure, the horizontal axis represents time and the vertical axis represents voltage (amplitude).

[0099] For example Figure 3 As shown in (a) of FIG. 8 , the excitation waveform can be set to a sine wave.

[0100] In addition, for example Figure 3 As shown in (b) of FIG. 8 , the excitation waveform can be a waveform obtained by superimposing (combining) a plurality of sinusoidal waves having different wavelengths.

[0101] In addition, the excitation waveform is not limited to these, and can be changed appropriately.

[0102] For example, various waveforms such as rectangular waves, triangular waves, and waveforms simulating the sound of a vehicle running can be used alone as the excitation waveform, or various waveforms such as rectangular waves, triangular waves, and waveforms simulating the sound of a vehicle running can be combined with other waveforms and used.

[0103] In the first embodiment, the frequency of the excitation waveform can be set to, for example, 100 to 400 Hz, and more preferably, the main frequency can be set to a range of 150 to 300 Hz.

[0104] The reason is described below.

[0105] As sensory receptors that sense vibration when the air around the occupant is excited, there are Merkel cells, Meissner corpuscles, Pacinian corpuscles, and the like.

[0106] Figure 4 This is a diagram schematically showing the timing of electrical pulses emitted by a receptor when stimulated.

[0107] exist Figure 4 In the figure, the horizontal axis represents time, and the vertical axis represents pressure, and the electrical impulse generation states of Merkel cells, Meissner corpuscles, and Pacinian corpuscles, in order from the upper row.

[0108] Merkel cells respond relatively slowly to DC components.

[0109] The moment at which the rate of change (velocity) of the Meissner corpuscle in response to contact pressure occurs.

[0110] Pacinian corpuscles respond to instantaneous changes and have the highest sensitivity among these receptors.

[0111] As a receptor through which passengers perceive tiny vibrations as a combination of auditory and tactile information, Pacinian corpuscles are believed to have the highest sensitivity.

[0112] Figure 5 Graphs showing the distribution of the sensitivity of Pacinian corpuscles and Meissner corpuscles with respect to frequency.

[0113] exist Figure 5 In FIG. 1 , the horizontal axis represents the frequency and the vertical axis represents the amplitude at the threshold value, and it is shown that the smaller the value, the better the sensitivity.

[0114] like Figure 5 As shown, the Pacinian corpuscles exhibit good sensitivity in the region around 100 to 400 Hz, and particularly exhibit better sensitivity in the region between 150 and 300 Hz.

[0115] Such an area is included in the range of 20 Hz to 20 kHz which is generally set as the audible range of humans.

[0116] As an example, the main frequency of the excitation waveform can be set to 250 Hz.

[0117] The differential calculation unit 120 acquires information on the steering angle σ of the front wheels FW detected by the steering angle sensor 71 from the electric power steering control unit 90 , and calculates a time-differentiated differential value Δσ.

[0118] The differential calculation unit 120 transmits the calculated differential values ​​Δσ one by one to the first gain adjustment unit 130 .

[0119] The first gain adjustment unit 130 performs a first gain adjustment, which will be described below, on the fundamental wave of the excitation waveform generated by the waveform generation unit 110 .

[0120] The first gain adjustment changes the gain G1 which is an output gain multiplied by the voltage of the excitation waveform, according to the differential value (rate of change per unit time) of the steering angle σ (a parameter related to the steering amount) of the steering device.

[0121] Figure 6 FIG. 1 is a diagram schematically showing an example of gain adjustment performed by the first gain adjustment unit.

[0122] exist Figure 6 In FIG. 1 , the horizontal axis represents the absolute value of the differential value Δσ of the steering angle σ of the wheel FW, and the vertical axis represents the gain G1 multiplied by the voltage of the excitation waveform.

[0123] The gain G1 can be configured to increase in accordance with an increase in the absolute value of the differential value Δσ.

[0124] Furthermore, the increase rate of the gain G1 in the first gain adjustment unit 130 with respect to the increase in the absolute value of the differential value Δσ can be configured to be the largest in a region where the absolute value of the differential value Δσ is small and to decrease in accordance with the increase in the absolute value of the differential value Δσ.

[0125] For example, the gain G1 in the first gain adjustment unit 130 can be calculated from the absolute value of the differential value Δσ of the steering angle σ using a logarithmic function.

[0126] The gain G1 is expressed by the following equation 1, for example.

[0127] Gain G1 = log (absolute value of steering angle differential value Δσ × coefficient k) (Formula 1) The coefficient k can be set to a value that is set, for example, at a vehicle development stage in accordance with the characteristics of the vehicle (for example, the yaw gain with respect to the steering angle σ, the position of the center of gravity, and the like).

[0128] The microphone 140 is a sound collecting device that is disposed in the vehicle compartment and collects background noise in the vehicle compartment.

[0129] Microphone 140 is preferably disposed at a position close to the ear of the occupant, and can be configured to be provided on a headrest portion of a seat, for example.

[0130] The output of the microphone 140 is transmitted to the sensing value calculation unit 150 .

[0131] The sensing value calculation unit 150 extracts a component of a predetermined frequency band from the background noise of the vehicle acquired by the microphone 140 , and transmits the sound pressure of the extracted component to the second gain adjustment unit 160 as a sensing value.

[0132] Figure 7FIG. 1 is a diagram schematically showing an example of a history of output from a microphone.

[0133] exist Figure 7 In FIG. 1 , the horizontal axis represents time, and the vertical axis represents the sound pressure of the background noise acquired by the microphone 140 .

[0134] The sensing value calculation unit 150 applies a fast Fourier transform (FFT) process to the sound signal of the background noise acquired by the microphone 140 to convert the sound signal into a frequency domain, and further applies a bandpass filter process to extract a component of a predetermined frequency band.

[0135] The extracted frequency band is set to include the main frequency of the excitation waveform output by the waveform generation unit 110 .

[0136] The sensing value calculation unit 150 sets the average sound pressure of the extracted frequency band as the sensing value used in the second gain adjustment.

[0137] Figure 8 This is a diagram showing an example of the relationship between the sound pressure and frequency of background noise.

[0138] exist Figure 8 In the figure, the horizontal axis represents frequency and the vertical axis represents sound pressure.

[0139] The bandpass filter can be configured to extract, for example, a frequency band around the main frequency (250 Hz as an example) of the excitation waveform in the waveform generation unit 110 .

[0140] The sound pressure in the extracted frequency band (as an example, the average value of the frequency band) is provided to the second gain adjustment unit 160 as a sensing value.

[0141] The second gain adjustment unit 160 further performs a second gain adjustment, which will be described below, on the excitation waveform after the first gain adjustment.

[0142] Since the second gain adjustment adjusts the output amplitude of the excitation waveform in response to changes in background noise (drive system noise, aerodynamic noise, road noise, etc.) when the vehicle is traveling, the gain of the excitation waveform changes in response to the sensed value of the noise in the vehicle cabin.

[0143] The second gain adjustment unit 160 performs second gain adjustment based on the output of the sensing value calculation unit 150 .

[0144] The second gain adjustment unit 160 sets the gain G2 based on the sensing value output by the sensing value calculation unit 150 .

[0145] Fig. 9 FIG. 1 is a diagram schematically showing an example of gain adjustment performed by the second gain adjustment unit.

[0146] exist Fig. 9In FIG. 1 , the horizontal axis represents the sensed value, and the vertical axis represents the gain G2 multiplied by the voltage of the excitation waveform.

[0147] The gain G2 can be configured to increase in accordance with an increase in the sensed value.

[0148] Gain G2 is set so that the sound pressure of the sound based on the excitation amplitude output from speaker 240 is not noticeable relative to the sound pressure of the background noise near the ears of the occupant.

[0149] Preferably, the gain G2 may be set so that the sound based on the excitation amplitude is mixed into the background noise of the vehicle and reaches a sound pressure level that the occupant can hear unconsciously.

[0150] In addition, in a state where the steering angle σ of the steering device is not generated, the sound pressure of the sound outputted from the speaker 240 based on the excitation amplitude is set to a standby state sufficiently lower than the sound pressure of the background noise of the vehicle.

[0151] The output value (voltage) A of the excitation waveform after the first gain adjustment and the second gain adjustment described above is expressed as Equation 2.

[0152] Output value A = waveform generation unit output value × gain G1 × gain G2 = waveform generation unit output value × log (absolute value of steering angle differential value Δσ × coefficient k) × gain G2 (Formula 2) A portion of the output of the second gain adjustment section 160 is directly delivered to the speaker 240 as a base term.

[0153] Another part of the output of the second gain adjustment unit 160 is transmitted to the speaker 240 as a correction term after being subjected to further gain adjustment as described below.

[0154] Here, the correction term reflects the influence of the lateral acceleration and jerk acting on the occupant due to the yaw rate and yaw acceleration of the vehicle.

[0155] Fig.10 This is a diagram showing an example of the lateral acceleration and lateral jerk of each seat row and the yaw rate of the vehicle body when a vehicle having three rows of seats starts turning.

[0156] The vertical axis represents the lateral acceleration, lateral jerk (acceleration of lateral acceleration), and yaw rate in order from the upper figure, and the horizontal axis represents time.

[0157] In a vehicle having three rows of seats arranged in sequence from the front side of the vehicle, it is known that even in the same vehicle, the time when lateral acceleration and lateral jerk are sensed and the magnitude of lateral acceleration and lateral jerk vary in the rear seats relative to the front seats.

[0158] Such a phenomenon is considered to occur due to the difference in relative position between the neutral turning point, which is the rotation center of the yaw behavior of the vehicle body, and each seating position.

[0159] Therefore, in the present embodiment, the position of the neutral steering point NSP of the vehicle is calculated, and the output gain of the excitation waveform is corrected as follows based on the relative position between the neutral steering point NSP and each seating position.

[0160] The neutral steering point calculation unit 170 calculates the position of the neutral steering point NSP based on information on the steering angle σ transmitted from the electric power steering control unit 90 , outputs of the yaw rate sensor 180 and the vehicle speed sensor 190 , and the like.

[0161] The yaw rate sensor 180 is a sensor that detects the yaw rate γ which is the rotation speed in the yaw direction of the vehicle.

[0162] The vehicle speed sensor 190 is, for example, a sensor provided in a hub portion that supports a wheel and outputs a vehicle speed signal corresponding to the rotation speed of the wheel.

[0163] The vehicle speed V can be calculated from the vehicle speed signal.

[0164] Fig.11 Graph showing the resultant force generated by the vehicle body slip angle.

[0165] like Fig.11 As shown, when the vehicle body generates a slip angle β, the front wheels FW and the rear wheels RW generate lateral forces (steering forces) corresponding to the slip angle β and the rigidities (steering powers) Kf and Kr, respectively.

[0166] The point at which the yaw moment of the vehicle generated by the steering forces generated by the front wheels FW and the rear wheels RW is balanced is the neutral steering point NSP.

[0167] When defined as follows, Formula 3 holds true.

[0168] l: Wheelbase l f : The distance from the center of gravity of the vehicle to the front axle l r : The distance from the center of gravity of the vehicle to the rear axle l N : The distance from the center of gravity of the vehicle to the neutral turning point β: Vehicle body slip angle K f : Stiffness of the front wheel FW (steering power Cp) K r : Stiffness of rear wheel RW (steering power Cp)

Mathematical formula 1

[0169] From formula 3, we can get the following formula 4.

[0170]

Mathematical formula 2

[0171] If γ = yaw rate A = stability factor σ = actual steering angle (steering amount) V = vehicle speed m = vehicle mass, Then the following equations 5 to 7 hold true.

[0172]

Mathematical formula 3

[0173] Fig.12 This is a diagram showing an example of a seat arrangement in a vehicle cabin in the first embodiment.

[0174] The vehicle has, for example, a first row of seats S1 , a second row of seats S2 , and a third row of seats S3 arranged in the front-rear direction, and each row of seats has a plurality of (eg, a pair of) seating positions arranged in the vehicle width direction.

[0175] exist Fig.12 In the illustrated example, the center of gravity CG of the vehicle is disposed, for example, near the left and right seating positions of the first row of seats S1 (between the driver's seat and the front passenger seat).

[0176] The neutral steering point NSP is arranged on the rear side of the center of gravity CG and in front of the axle position of the rear wheel RW.

[0177] The front-rear direction position of the neutral steering point NSP changes, for example, depending on the vehicle speed, and changes during a period from a transient state (at the start of a turn) to a steady state at the same vehicle speed.

[0178]

Mathematical formula 4

[0179]

Mathematical formula 5

[0180] In addition, at the angle θ (refer to Fig.12) and the vehicle body slip angle β is set to φ, the following equation 9 holds.

[0181]

Mathematical formula 6

[0182] The third gain adjustment section 200 , the fourth gain adjustment section 210 , and the fifth gain adjustment section 220 sequentially adjust the output gain of the correction term of the excitation waveform output from the second gain adjustment section 160 .

[0183] The third gain adjustment unit 200 adjusts the output gain (third gain adjustment) based on the distance between the neutral steering point NSP calculated by the neutral steering point calculation unit 170 and the seated position of the occupant (particularly the position of the head (ear)).

[0184] Fig.13 FIG. 1 is a diagram schematically showing an example of gain adjustment performed by the third gain adjustment unit.

[0185] exist Fig.13 , the horizontal axis represents the distance between the neutral steering point NSP and the seated position of the occupant, and the vertical axis represents the gain G3 multiplied by the voltage of the excitation waveform (correction term).

[0186] The absolute value of the gain G3 increases in accordance with the increase in the absolute value of the distance.

[0187] Furthermore, when the distance becomes negative (when the occupant is seated rearward with respect to the neutral steering point NSP), the gain G3 becomes negative.

[0188] In this case, the acceleration and jerk to which the occupant is subjected due to the yaw behavior of the vehicle body acts to cancel the acceleration and jerk to which the occupant is subjected due to the centripetal acceleration accompanying the turning of the vehicle. That is, the acceleration and jerk felt by the occupant are reduced.

[0189] When the distance between the neutral steering point NSP and the seated position of the occupant is zero (the positions of both coincide with each other), the gain G3 becomes zero and the correction term disappears.

[0190] The fourth gain adjustment unit 210 adjusts the vehicle body according to the angle difference φ between the slip angle β and the angle θ (see Fig.12 ) is used to adjust the output gain (fourth gain adjustment), where the angle θ is the angle formed by a straight line connecting the neutral steering point NSP and the seat position of the occupant relative to the center line of the vehicle body.

[0191] exist Fig.12 , a state is shown in which the passenger P is seated, for example, on the left side (passenger seat) of the first row of seats S1.

[0192] FIG. 1 is a diagram schematically showing an example of gain adjustment in the fourth gain adjustment unit.

[0193] Fig.14 FIG. 1 is a diagram schematically showing an example of gain adjustment performed by the fourth gain adjustment unit.

[0194] exist Fig.14 In FIG. 1 , the horizontal axis represents the angle difference φ, and the vertical axis represents the gain G4 multiplied by the voltage of the excitation waveform (correction term).

[0195] The gain G4 reaches a maximum when the angle difference φ=0, and decreases thereafter in accordance with an increase in the absolute value of the angle difference φ.

[0196] When the angle difference φ reaches ±90°, the gain G4 becomes zero.

[0197] The fifth gain adjustment unit 220 adjusts the output gain according to the vehicle speed φ and φ (fifth gain adjustment).

[0198] The fifth gain adjustment unit 220 adjusts the output gain based on the outputs of the vehicle speed sensor 190 and the load sensor 230 .

[0199] The load sensor 230 includes, for example, a stroke sensor that detects the stroke of a suspension device (usually a rear suspension).

[0200] Based on the output of the load sensor 230 , the fifth gain adjustment unit 220 can determine the load state of the vehicle, such as the number of passengers and / or the loading state of cargo.

[0201] Fig.15 FIG. 1 is a diagram schematically showing an example of gain adjustment performed by the fifth gain adjustment unit.

[0202] exist Fig.15 In FIG. 1 , the horizontal axis represents the vehicle speed, and the vertical axis represents the gain G5 multiplied by the voltage of the excitation waveform (correction term).

[0203] The gain G5 is set to decrease in accordance with an increase in the vehicle speed.

[0204] In addition, a plurality of maps (line graphs) are provided for the gain G5 according to the load state of the vehicle.

[0205] Fig.16 This is a diagram schematically showing an example of the steering force characteristics of a tire corresponding to a load change.

[0206] exist Fig.16 In FIG. 8 , the horizontal axis represents the tire slip angle, and the vertical axis represents the steering force CF.

[0207] Fig.17This is a diagram schematically showing an example of the steering power characteristics of the tire corresponding to the load change.

[0208] exist Fig.17 In the figure, the horizontal axis represents the tire slip angle, and the vertical axis represents the steering power CP.

[0209] like Fig.16 , Fig.17 As shown, since the characteristics of the tire vary depending on the load, Fig.15 The map (line graph) of the gain G5 shown can be switched appropriately according to the loading state of the vehicle detected by the load sensor 230 .

[0210] The speaker 240 is an excitation device disposed in the vehicle cabin and uses the output value A of the excitation waveform after the first to fifth gain adjustments to excite the air around the occupants in the vehicle cabin to generate sound.

[0211] For example, the speaker 240 may be configured to be shared with a speaker used for sound reproduction of an in-vehicle audio system.

[0212] In addition, a configuration may be adopted in which a speaker 240 dedicated to the information transmission device 100 is provided.

[0213] like Fig.12 As shown, when the first to third row seats have left and right seating positions respectively, speakers 240 can be configured such that at least six speakers 240 are provided corresponding to the respective seating positions.

[0214] Each speaker 240 can be a directional speaker directed toward the vicinity of the head (ear) of the occupant seated at each seating position.

[0215] Speaker 240 can be configured to be provided inside a vehicle interior component such as an instrument panel, a door trim, a pillar trim, etc. and / or a headrest or a backrest of a seat arranged directly in front of an occupant.

[0216] Here, the third and fourth gain adjustments among the above-mentioned gain adjustments are independently performed for each speaker 240 according to the seated position of the occupant to which each speaker 240 is directed.

[0217] That is, the amplitude of the excitation waveform of each speaker 240 differs according to the seating position of the corresponding occupant.

[0218] According to the first embodiment described above, the following effects can be obtained.

[0219] (1) By generating a sound whose sound pressure increases in accordance with the increase in the absolute value of the differential value of the steering angle σ of the steering device (so-called steering speed), the occupant P can be foreseen by the sound at the beginning of the steering before the vehicle actually generates lateral acceleration, yaw rate, roll angle, etc.

[0220] This improves the predictability of the vehicle behavior by the occupant P, and prevents the occupant P from feeling a sense of abruptness regarding the vehicle behavior.

[0221] In addition, by adjusting the output gain of the excitation waveform according to the relative position between the neutral steering point NSP, which is the rotation center of the yaw behavior, and the seating position of the occupant P, information that appropriately reflects the effects of lateral acceleration and jerk on the occupant P due to the yaw behavior of the vehicle can be transmitted. This can suppress the deviation between the sound information transmitted to the occupant P by the speaker 240 and the lateral acceleration, etc. actually experienced by the occupant, and improve the predictability of the behavior caused by the turning of the vehicle regardless of the seating position in the vehicle cabin.

[0222] In particular, in the second row and subsequent seats, where there is less visual information and the behavior of the vehicle is more likely to feel abrupt compared to the first row seats S1, the predictability of the vehicle behavior can be improved, thereby reducing the abrupt feeling and preventing motion sickness.

[0223] (2) The third gain adjustment unit 200 changes the output gain in accordance with the change in the distance between the neutral steering point NSP and the seating position, thereby reflecting that the acceleration and jerk to which the occupant P is subjected changes in accordance with the increase in the distance from the neutral steering point NSP to the seating position, thereby enabling appropriate information to be transmitted to the occupant P.

[0224] (3) The fourth gain adjustment unit 210 can appropriately estimate the lateral components of the acceleration and jerk to which the occupant P is subjected due to the change in the yaw angular acceleration of the vehicle body, and transmit appropriate information to the occupant P by reducing the output gain in accordance with an increase in the angle difference φ, which is the angle difference between the slip angle β of the vehicle body and the angle θ formed by a straight line connecting the neutral steering point NSP and the seating position with respect to the center line of the vehicle body when viewed from above.

[0225] (4) A plurality of seating positions are provided, and a plurality of speakers 240 are provided corresponding to the plurality of seating positions. By making the amplitudes of the excitation waveforms output by the plurality of speakers 240 different according to the relative positions between the neutral turning point NSP and the seating positions, appropriate information corresponding to the seating positions can be transmitted to the plurality of occupants P seated at the plurality of seating positions.

[0226] (5) Since the excitation waveform has a main frequency included in the frequency band of 100 to 400 Hz, it is possible to use Pacinian corpuscles and the like which are highly sensitive in the audible range and highly sensitive in terms of skin sensation, and the perception of sound and skin sensation of the occupant P based on the sound are improved. Therefore, information can be transmitted to the occupant P more reliably.

[0227] <Second embodiment> Next, a second embodiment of the information transmission device to which the present invention is applied will be described.

[0228] In the second embodiment, the vehicle has an automatic driving function that autonomously performs steering operation, acceleration and deceleration operation, and the like without relying on the driving operation of the driver.

[0229] Fig.18 It is a diagram schematically showing the configuration of an automatic driving system of a vehicle provided with the information transmission device according to the second embodiment.

[0230] The automatic driving system 300 includes an automatic driving control unit 310 , an engine control unit 320 , a transmission control unit 330 , a brake control unit 340 , and the like in addition to the electric power steering control unit 90 described above.

[0231] Each of these units includes a microcomputer having an information processing unit such as a CPU, a storage unit such as a RAM and / or a ROM, an input / output interface, and a bus that connects them.

[0232] In addition, the units are connected via an in-vehicle LAN such as a CAN communication system or directly connected, and can communicate with each other.

[0233] The automatic driving control unit 310 recognizes the environment around the vehicle using various sensors such as a stereo camera device, a millimeter wave radar device, a laser scanner device, and a high-precision 3D map.

[0234] The automatic driving control unit 310 generates an automatic driving scenario including information related to the driving route, speed, etc. of the host vehicle based on the recognized environment.

[0235] Based on the autonomous driving scenario, the autonomous driving control unit 310 provides instructions to the electric power steering control unit 90, the engine control unit 320, the transmission control unit 330, and the brake control unit 340, thereby controlling the steering and acceleration and deceleration of the vehicle.

[0236] The electric power steering control unit 90 controls the actuator unit 80 according to the requested steering angle instructed by the automatic driving control unit 310 instead of the steering input from the driver as in the first embodiment, thereby steering the front wheels FW.

[0237] The engine control unit 320 centrally controls the engine and its auxiliary machines, which are the driving power sources of the vehicle.

[0238] The engine control unit 320 controls the output of the engine so that the torque actually generated by the engine matches the request torque indicated by the automatic driving control unit 310 .

[0239] The transmission control unit 330 centrally controls the transmission and its auxiliary machines for changing the speed (decelerating or increasing the speed) of the rotation of the output shaft of the engine.

[0240] The transmission control unit 330 performs switching between a driving range and a non-driving range, switching between forward and reverse travel, and speed change (speed ratio change) during forward travel, etc., according to instructions from the automatic driving control unit 310 .

[0241] The brake control unit 340 controls the braking force of the hydraulic service brake provided on each wheel of the vehicle.

[0242] The brake control unit 340 adjusts the brake fluid pressure supplied to the wheel cylinder of each wheel according to the requested braking force instructed by the automatic driving control unit 310, thereby generating the required braking force.

[0243] In the second embodiment, even during the automatic driving when the driver does not perform any steering operation, the indicated value of the requested steering angle transmitted from the automatic driving control unit 310 to the electric power steering control unit 90 is used as the input of the information transmission device 100 (a parameter related to the steering angle of the steering device), and a first gain adjustment is performed based on its differential value.

[0244] According to the second embodiment described above, since in a vehicle performing automatic driving, a sound corresponding to the absolute value of the differential value of the steering angle and the positional relationship between the neutral steering point NSP and the seating position is generated when steering based on the automatic driving control is started, the occupants can foresee the occurrence of vehicle behavior accompanied by the generation of lateral acceleration, yaw rate, roll angle, etc., thereby preventing the occupants from feeling abrupt about the vehicle's behavior.

[0245] (Variation) The present invention is not limited to the above-described embodiments, and various modifications and changes are possible, which are also within the technical scope of the present invention.

[0246] (1) The configurations of the information transmission device and the vehicle are not limited to the above-described embodiments, and can be modified as appropriate.

[0247] For example, the number and arrangement of seating positions in the vehicle cabin, the arrangement of speakers corresponding thereto, and the like can be appropriately changed according to the configuration of the embodiment.

[0248] In addition, the hardware configuration of the information transmission device and the specific method of gain adjustment (amplitude change) of the excitation waveform are not limited to the configurations of the respective embodiments, and can be changed as appropriate.

[0249] (2) In each embodiment, the parameter related to the steering amount of the steering device is, for example, the steering angle (the actual steering angle detected by the steering angle sensor or the requested steering angle in the automatic driving control). However, the parameter is not limited thereto and can be changed as appropriate.

[0250] For example, it can be configured to have at least one of a steering torque (input torque) input by a driver, an operation amount of an actuator for steering wheels (for example, a rotation amount of a motor), an output instruction value for the actuator, and the like.

[0251] (3) The present invention is not limited to being applied to a vehicle having a steering device in which an operating member such as a steering wheel is mechanically connected to a steering mechanism such as a steering gear box as in the various embodiments, but can also be applied to a vehicle having a steer-by-wire steering device in which a steering wheel or the like is not mechanically connected to a steering mechanism. In this case, the actual steering angle of the front wheels and the state of the steering mechanism (for example, the rotation angle position of the pinion and / or the movement amount of the rack shaft) can be used as parameters related to the steering amount of the steering device.

[0252] (4) In each embodiment, as an example, the level of the background noise of the vehicle is acquired using a microphone, but the present invention is not limited thereto and the level of the background noise may be acquired using other methods. For example, the level of the background noise may be estimated based on the acceleration of the unsprung portion of the vehicle related to the input from the road surface and the output value of the torque sensor of the steering device (torsion bar torque).

Claims

1. An information transmission device, characterized in that: The vehicle is provided with a steering device for steering wheels, The information transmission device comprises: a parameter detection unit for detecting a parameter related to a steering amount of the steering device; an excitation unit for exciting the air around the occupant using a predetermined excitation waveform according to a change in the parameter of the steering device; A rotation center calculation unit that calculates the position of the rotation center of the yaw behavior of the vehicle body; as well as A gain adjustment unit adjusts an output gain of the excitation waveform according to a relative position between the rotation center and a seated position of the occupant.

2. The information transmission device according to claim 1, characterized in that: The gain adjustment unit changes the output gain in accordance with a change in the distance between the rotation center and the seating position.

3. The information transmission device according to claim 1 or 2, characterized in that: The gain adjustment unit reduces the output gain in accordance with an increase in an angle difference between a slip angle of a vehicle body and an angle formed by a straight line connecting the rotation center and the seat position with respect to a center line of the vehicle body in a plan view.

4. The information transmission device according to claim 1 or 2, characterized in that: There are multiple seating positions. The excitation unit is provided in plurality corresponding to the plurality of seating positions. The amplitudes of the excitation waveforms output by the plurality of excitation units are made different according to the relative position between the rotation center and the seated position.

5. The information transmission device according to claim 1 or 2, characterized in that: The excitation waveform has a main frequency included in a frequency band of 100 to 400 Hz.

6. The information transmission device according to claim 1 or 2, characterized in that: The vehicle includes an automatic driving control unit, and the automatic driving control unit instructs the steering device about the steering amount. The parameter related to the steering amount of the steering device is an instruction value of the automatic driving control unit.

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