Sheet device

Abstract

To prevent motion sickness caused by lateral acceleration in the vehicle without tilting the seat surface. [Solution] The seat device 100 includes a seat 20, an actuator 30 that adjusts the tilt angle θ of the seat back 22 relative to the seat portion 21, and a processing circuit 41 that performs a backward tilting process that activates the actuator 30 to rotate the seat back 22 in the backward tilting direction Rr when lateral acceleration occurs in the vehicle. The processing circuit 41 sets a reference backward tilting angular velocity based on the longitudinal acceleration detection value or a predetermined value. In the backward tilting process when the magnitude of the lateral acceleration detection value is greater than a threshold, the processing circuit 41 rotates the seat back 22 in the backward tilting direction Rr at an angular velocity greater than the reference backward tilting angular velocity or a predetermined value.

Description

Technical Field

[0001] The present disclosure relates to a seat device including a seat mounted on a vehicle.

Background Art

[0002] In studies on suppressing motion sickness of vehicle occupants, for example, Patent Document 1 discloses an occupant posture control device that suppresses an occupant from suffering from motion sickness due to the occurrence of lateral acceleration in a vehicle. The device includes an actuator that applies a stimulus that generates muscle tension to the occupant, and the actuator applies muscle tension to the occupant by tilting the seat surface of the seat.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, in the above-mentioned occupant posture control device, in order to apply muscle tension to an occupant sitting on the seat, it is necessary to tilt the seat surface of the seat by operating the above-mentioned actuator. As a result, there are concerns about an increase in cost and complication of the control mechanism due to an increase in the actuator.

Means for Solving the Problems

[0005] To solve the above problems, we focused on applying muscle tension by tilting the seat forward and backward. Specifically, the seat device of this disclosure is applied to a vehicle equipped with a longitudinal acceleration sensor for detecting the longitudinal acceleration of the vehicle and a lateral acceleration sensor for detecting the lateral acceleration of the vehicle. The seat device comprises a seat having a seat portion and a seat back, an actuator for adjusting the tilt angle, which is the angle of the seat back relative to the seat portion, a control unit that performs a backward tilting process to rotate the seat back in a backward tilting direction, which is the rotation direction of the seat back that increases the tilt angle when the lateral acceleration occurs in the vehicle, and a setting unit that sets a reference backward tilting angular velocity based on the longitudinal acceleration detection value, which is the detection value of the longitudinal acceleration sensor, or a predetermined value. In the backward tilting process when the magnitude of the lateral acceleration detection value, which is the detection value of the lateral acceleration sensor, is greater than a threshold, the control unit rotates the seat back in the backward tilting direction at an angular velocity greater than the reference backward tilting angular velocity or a predetermined value. [Effects of the Invention]

[0006] The above-described seat device has the effect of suppressing motion sickness in occupants caused by lateral acceleration in the vehicle, without tilting the seat surface. [Brief explanation of the drawing]

[0007] [Figure 1] Figure 1 is a schematic diagram showing the basic structure of a vehicle with multiple seats installed inside the passenger compartment. [Figure 2] Figure 2 is a schematic diagram showing the sheet device of the first embodiment. [Figure 3] Figure 3 is a block diagram showing the functional configuration of the control device included in the seat device shown in Figure 2. [Figure 4] Figure 4 is a flowchart showing a series of processes performed by the control device in Figure 2. [Figure 5] Figure 5 is a schematic diagram showing how the seat back rotates in the backward direction due to the backward tilting process. [Figure 6]Figure 6 is a schematic diagram illustrating how the occupant's entire body tenses up due to the backward rotation of the seatback caused by the backward tilting process. [Figure 7] Figure 7 is a flowchart showing an example of a subroutine executed by the control device while the backward tilting process is being performed in the seat device of the second embodiment. [Figure 8] Figure 8 is a schematic diagram illustrating the various forces experienced by the occupant when the seatback is rotated in a backward-tilting direction in an example of a modified seat system. [Modes for carrying out the invention]

[0008] (First Embodiment) A first embodiment of the sheet device will be described with reference to Figures 1 to 6. Figure 1 illustrates a vehicle 10 equipped with a seating device 100 (see Figure 2). The vehicle 10 comprises a plurality of wheels 11 and a vehicle body 12. The passenger compartment of the vehicle body 12 is provided with a plurality of seats 20 in which the passengers 200 of the vehicle 10 are seated. The plurality of seats 20 are installed in the passenger compartment such that the front of the passengers 200 seated in the seats 20 faces the front of the vehicle Xf. The direction opposite to the front of the vehicle Xf is referred to as the rear of the vehicle Xr.

[0009] <Sheet device> The sheet device 100 will be described with reference to Figures 1 and 2. The seating device 100 comprises a seat 20, an actuator 30, and a control device 40.

[0010] The seat 20 comprises a seat portion 21, a seat back 22, and a headrest 23. The headrest 23 is supported on the top of the seat back 22 via two stays 23a.

[0011] The seat back 22 has a support surface 22a that supports the back of the occupant 200. The seat back 22 is rotatable relative to the seat 21. That is, a pivot axis 21A extending laterally from the vehicle 10 is provided at the rear Xr end of the seat 21. The seat 20 is configured so that the seat back 22 can rotate around the pivot axis 21A. The angle of the seat back 22 relative to the seat 21 is referred to as the "tilt angle θ". The tilt angle θ changes as the seat back 22 rotates.

[0012] Of the rotational directions around the rotation axis 21A, the counterclockwise direction in Figure 2 is described as the "forward tilt direction Rf," and the clockwise direction in Figure 2 is described as the "rearward tilt direction Rr." The rearward tilt direction Rr is the opposite direction to the forward tilt direction Rf. The forward tilt direction Rf is the rotational direction that displaces the headrest 23 forward Xf of the vehicle. The rearward tilt direction Rr is the rotational direction that displaces the headrest 23 backward Xr of the vehicle. When the seat back 22 rotates in the forward tilt direction Rf, the tilt angle θ decreases. As a result, the posture of the occupant 200 changes so that the occupant 200 leans forward. On the other hand, when the seat back 22 rotates in the rearward tilt direction Rr, the tilt angle θ increases. As a result, the posture of the occupant 200 changes so that the occupant 200 leans backward.

[0013] The actuator 30 operates to adjust the tilt angle θ. The actuator 30 is, for example, built into the seat 21. When the actuator 30 operates, the seat back 22 rotates in the forward tilt direction Rf or the seat back 22 rotates in the backward tilt direction Rr.

[0014] The control device 40 has a processing circuit 41 that controls the posture of the seat 20. An example of the processing circuit 41 is an electronic control device. The processing circuit 41 has a CPU 42 and a memory 43 that stores a control program executed by the CPU 42. By the CPU 42 executing the control program in the memory 43, the processing circuit 41 can operate the actuator 30 to control the tilt angle θ.

[0015] <Vehicle detection system> The detection system of the vehicle 10 includes a longitudinal acceleration sensor 61 that detects the longitudinal acceleration of the vehicle 10 and a lateral acceleration sensor 62 that detects the lateral acceleration of the vehicle 10. The longitudinal acceleration sensor 61 and the lateral acceleration sensor 62 output detection signals to the control device 40. The longitudinal acceleration based on the detection signal of the longitudinal acceleration sensor 61 is referred to as "longitudinal acceleration detection value Gx". The lateral acceleration based on the detection signal of the lateral acceleration sensor 62 is referred to as "lateral acceleration detection value Gy".

[0016] The detection system of the vehicle 10 includes a monitoring system that monitors the occupant 200 sitting on the seat 20. The monitoring system includes, for example, an imaging device 65 that images the occupant 200. The imaging device 65 is installed at a position where it can image at least one of the upper limb and the face of the occupant 200. Image data PD, which is the data of the image captured by the imaging device 65, is transmitted to the control device 40.

[0017] <Other in-vehicle control devices> The vehicle 10 is equipped with other control devices other than the above-mentioned control device 40. The other control devices include, for example, a driving support device 80. The driving support device 80 is configured to be able to execute various processes for supporting the running of the vehicle 10.

[0018] The driving support device 80 can acquire information outside the vehicle. The information outside the vehicle includes, for example, the presence or absence of an obstacle existing in front of the vehicle 10 and the collision margin time TM with respect to the obstacle. The collision margin time TM is a value obtained by dividing the distance from the obstacle existing in front of the vehicle 10 to the vehicle 10 by the approaching speed of the vehicle 10 to the obstacle. The driving support device 80 transmits the information outside the vehicle as described above to the control device 40 via the in-vehicle network 90.

[0019] <Functional configuration of the control device of the seat device> Referring to FIG. 3, the functional configuration of the control device 40 will be described. The processing circuit 41 of the control device 40 functions as various functional units for controlling the seat 20, with the CPU 42 executing a control program in the memory 43. The functional units include a detection value acquisition unit 301, a crew information acquisition unit 302, a setting unit 304, a prediction unit 306, and a control unit 308.

[0020] <Detection value acquisition unit and crew information acquisition unit> The detection value acquisition unit 301 acquires longitudinal acceleration detection value Gx and lateral acceleration detection value Gy at predetermined intervals.

[0021] The occupant information acquisition unit 302 acquires occupant information, which is information about the occupant 200 seated in the seat 20, at predetermined intervals. The occupant information acquisition unit 302 acquires occupant information, for example, by analyzing image data PD transmitted from the imaging device 65. The predetermined interval may be, for example, each predetermined operation including at least one of the following: turning on the ignition switch, pressing the accelerator pedal, and pressing the brake pedal, or it may be at predetermined intervals of time. The occupant information acquisition unit 302 may also acquire information related to the weight of the occupant 200 as occupant information. Information related to the weight of the occupant 200 may include, for example, information on whether the occupant 200 is an adult or a child, and information on the gender of the occupant 200.

[0022] <Settings section> As will be explained in more detail later, the control device 40 performs a backward tilting process that rotates the seat back 22 in the backward tilting direction Rr when lateral acceleration occurs in the vehicle 10. The rotational angular velocity of the seat back 22 in the backward tilting direction Rr is referred to as the "backward tilting angular velocity," and the reference value of the backward tilting angular velocity of the seat back 22 associated with the execution of the backward tilting process is referred to as the "reference backward tilting angular velocity SPRrB."

[0023] The reference reclining angular velocity SPRrB is the maximum reclining angular velocity that can suppress a reduction in the degree to which the occupant 200 leans against the seat back 22 when the seat back 22 is rotated in the reclining direction Rr. The degree to which the occupant 200 leans against the seat back 22 correlates with the normal force that the occupant 200's back receives from the support surface 22a of the seat back 22. When the seat back 22 rotates in the reclining direction Rr, if the reclining angular velocity is greater than the reference reclining angular velocity SPRrB, it can be inferred that the degree to which the occupant 200 leans against the seat back 22 will decrease, or that the occupant 200's back will move away from the support surface 22a.

[0024] The setting unit 304 calculates the reference backward tilt angular velocity SPRrB at predetermined intervals based on a predetermined value or the forward / backward acceleration detection value Gx. When the setting unit 304 sets the reference rear tilt angular velocity SPRrB based on the predetermined value described above, it is preferable for the setting unit 304 to set the reference rear tilt angular velocity SPRrB to a value in the range of 1 deg / s or more and 10 deg / s or less. It is more preferable for the setting unit 304 to set the reference rear tilt angular velocity SPRrB to a value in the range of 3 deg / s or more and 9 deg / s or less, and even more preferable for it to set the reference rear tilt angular velocity SPRrB to a value in the range of 4 deg / s or more and 8 deg / s or less. By having the predetermined value described above within this range, the discomfort caused to the occupant by the rear tilting process is likely to be reduced.

[0025] When the setting unit 304 sets the reference rear tilt angular velocity SPRrB based on the detected longitudinal acceleration value Gx, it is preferable that the setting unit 304 sets the reference rear tilt angular velocity SPRrB such that there is a positive correlation between the magnitude of the detected longitudinal acceleration value Gx and the reference rear tilt angular velocity SPRrB.

[0026] The setting unit 304 may calculate the reference rear tilt angular velocity SPRrB by considering not only the longitudinal acceleration detection value Gx but also occupant information. For example, the setting unit 304 sets the reference rear tilt angular velocity SPRrB such that there is a positive correlation between the weight of occupant 200, which can be estimated from the occupant information, and the reference rear tilt angular velocity SPRrB.

[0027] <Prediction Section> The prediction unit 306 predicts the occurrence of sudden braking by the vehicle 10. The prediction unit 306 predicts the occurrence of sudden braking based on external information received from the driver assistance device 80. For example, the prediction unit 306 predicts the occurrence of sudden braking when the collision margin time TM is less than the time determination value TMth. An example of the time determination value TMth is a predetermined value that serves as a criterion for determining whether or not the vehicle 10 is likely to collide with an obstacle. That is, when the collision margin time TM is less than the time determination value TMth, it means that the vehicle 10 is more likely to collide with an obstacle compared to when the collision margin time TM is equal to or greater than the time determination value TMth. When the collision margin time TM is less than the time determination value TMth, sudden braking occurs in the vehicle 10 for the purpose of avoiding a collision between the vehicle 10 and the obstacle or mitigating the damage caused by such a collision. Therefore, predicting the occurrence of sudden braking based on the collision margin time TM can also be said to be predicting that the vehicle 10 is likely to collide with an obstacle.

[0028] <Department Head> When a lateral acceleration occurs in the vehicle 10, the control unit 308 performs a backward tilting process by activating the actuator 30 to rotate the seat back 22 in the backward tilting direction Rr.

[0029] In the backward tilting process, the control unit 308 sets the target backward tilting angular velocity SPRrTr, which is the target value of the backward tilting angular velocity, based on the reference backward tilting angular velocity SPRrB and the detected lateral acceleration value Gy. Specifically, the control unit 308 sets the target rear tilt angular velocity SPRrTr to a velocity greater than the reference rear tilt angular velocity SPRrB when the magnitude of the detected lateral acceleration value Gy is greater than the lateral acceleration threshold Gyth. The lateral acceleration threshold Gyth is a predetermined value for determining whether or not a large lateral acceleration is acting on the vehicle 10. If the magnitude of the detected lateral acceleration value Gy is greater than the lateral acceleration threshold Gyth, it is considered that a large lateral acceleration is acting on the vehicle 10. If the magnitude of the detected lateral acceleration value Gy is less than or equal to the lateral acceleration threshold Gyth, it is considered that no large lateral acceleration is acting on the vehicle 10.

[0030] The control unit 308 then operates the actuator 30 so that the seat back 22 rotates in the backward tilt direction Rr at a set target backward tilt angular velocity SPRrTr. The control unit 308 may set a predetermined value to the target reclining angular velocity SPRrTr. In this case, the control unit 308 may set a value in the range of 2 deg / s or more and 20 deg / s or less to the target reclining angular velocity SPRrTr. It is more preferable for the control unit 308 to set a value in the range of 4 deg / s or more and 15 deg / s or less to the target reclining angular velocity SPRrTr. It is even more preferable for the control unit 308 to set a value in the range of 4 deg / s or more and 10 deg / s or less to the target reclining angular velocity SPRrTr. By having the predetermined value within this range, the reclining process makes it easier to separate the back of the occupant 200 from the support surface 22a.

[0031] When the control unit 308 is rotating the seat back 22 in the rearward direction Rr by the rearward tilting process, it stops the rearward tilting process when a predetermined stop condition is met. At this time, the control unit 308 stops the operation of the actuator 30 and maintains the tilt angle θ of the seat back 22.

[0032] When the control unit 308 is performing a backward tilting process, it monitors the change in the lateral acceleration velocity Jy, which is the time derivative of the detected lateral acceleration value Gy. The control unit 308 may determine that a predetermined stopping condition has been met when the magnitude of the lateral acceleration velocity Jy becomes smaller than the lateral acceleration velocity threshold Jyth. In this case, the lateral acceleration velocity threshold Jyth is a predetermined value that allows one to determine whether or not the increasing trend of the magnitude of the detected lateral acceleration value Gy has decreased.

[0033] The control unit 308 sets the magnitude of the detected lateral acceleration value Gy at the time the backward tilting process is stopped to the degradation start determination value Gymax. As described above, when the backward tilting process is stopped, the control unit 308 determines whether the conditions for starting the degradation process have been met. When the backward tilting process is stopped, the control unit 308 monitors the change in the magnitude of the lateral acceleration detected value Gy. When the magnitude of the lateral acceleration detected value Gy becomes smaller than the degradation start determination value Gymax, the control unit 308 determines that the conditions for starting the degradation process have been met. In other words, when the backward tilting process is stopped and the magnitude of the lateral acceleration detected value Gy becomes smaller than the degradation start determination value Gymax, the control unit 308 starts the degradation process.

[0034] During the decompression process, the control unit 308 operates the actuator 30 so that the seat back 22 rotates in the forward tilt direction Rf. The tilt angle θ before the start of the backward tilt process is referred to as the "initial tilt angle θF". At this time, during the decompression process, the control unit 308 rotates the seat back 22 in the forward tilt direction Rf until the tilt angle θ becomes the initial tilt angle θF.

[0035] In this situation, lateral acceleration may occur in vehicle 10 when sudden braking is predicted. For example, vehicle 10 may make a sharp turn to avoid a collision with an obstacle. In this case, lateral acceleration occurs in vehicle 10. However, if lateral acceleration occurs in vehicle 10 when sudden braking is predicted by the prediction unit 306, for example, the control unit 308 does not perform the backward tilting process.

[0036] <Seat posture adjustment process> Referring to Figure 4, the seat posture adjustment process, which is a series of processes performed by the control device 40, will be explained. The processing circuit 41 of the control device 40 starts executing the seat posture adjustment process when lateral acceleration occurs in the vehicle 10.

[0037] In step S11, the processing circuit 41 functions as a setting unit 304 to set the reference rear tilt angular velocity SPRrB based on the longitudinal acceleration detection value Gx or a predetermined value. At this time, the processing circuit 41 may also set the reference rear tilt angular velocity SPRrB taking into consideration occupant information.

[0038] In the following step S13, the processing circuit 41 determines whether the magnitude of the detected lateral acceleration Gy is greater than the lateral acceleration threshold Gyth. If the magnitude of the detected lateral acceleration Gy is greater than the lateral acceleration threshold Gyth (S13: YES), the processing circuit 41 proceeds to step S15. On the other hand, if the magnitude of the detected lateral acceleration Gy is less than or equal to the lateral acceleration threshold Gyth (S13: NO), the processing circuit 41 terminates the series of processes shown in Figure 4. In other words, even if lateral acceleration occurs in the vehicle 10, if the magnitude of the detected lateral acceleration Gy is less than or equal to the lateral acceleration threshold Gyth, the processing circuit 41 does not perform the backward tilting process.

[0039] In step S15, the processing circuit 41, functioning as a control unit 308, sets the target rear tilt angular velocity SPRrTr. At this time, the processing circuit 41 sets the target rear tilt angular velocity SPRrTr to a value obtained by increasing and correcting the reference rear tilt angular velocity SPRrB based on the detected lateral acceleration value Gy. Alternatively, the processing circuit 41 may set the above predetermined value to the target rear tilt angular velocity SPRrTr by functioning as a control unit 308.

[0040] In step S17, the processing circuit 41 starts the tilting process by functioning as the control unit 308. In step S19, the processing circuit 41, functioning as a control unit 308, determines whether the magnitude of the lateral acceleration velocity Jy is less than the lateral acceleration velocity threshold Jyth. If the magnitude of the lateral acceleration velocity Jy is greater than or equal to the lateral acceleration velocity threshold Jyth (S19: NO), the processing circuit 41 proceeds to step S17. The processing circuit 41 then continues the tilting process. On the other hand, if the magnitude of the lateral acceleration velocity Jy is less than the lateral acceleration velocity threshold Jyth (S19: YES), the processing circuit 41 proceeds to step S21.

[0041] In step S21, the processing circuit 41, functioning as a control unit 308, sets the magnitude of the current detected lateral acceleration value Gy to the degradation start determination value Gymax. In the subsequent step S23, the processing circuit 41 stops the backward tilting process.

[0042] In the next step S25, the processing circuit 41 determines whether the current magnitude of the detected lateral acceleration Gy is less than the degradation start determination value Gymax. If the magnitude of the detected lateral acceleration Gy is greater than or equal to the degradation start determination value Gymax (S25: NO), the processing circuit 41 repeatedly performs the determination in step S25 until the magnitude of the detected lateral acceleration Gy becomes less than the degradation start determination value Gymax. On the other hand, if the magnitude of the detected lateral acceleration Gy is less than the degradation start determination value Gymax (S25: YES), the processing circuit 41 proceeds to step S27.

[0043] In step S27, the processing circuit 41 performs a degraded process by functioning as a control unit 308. At this time, the processing circuit 41 sets the target forward tilt angular velocity SPRfTr to a value obtained by inverting the sign of the target backward tilt angular velocity SPRrTr. Then, the processing circuit 41 operates the actuator 30 so that the seat back 22 rotates in the forward tilt direction Rf at the target forward tilt angular velocity SPRfTr.

[0044] In the degraded processing, one example is to set the target forward tilt angular velocity SPRfTr to a value obtained by inverting the sign of the target backward tilt angular velocity SPRrTr. In other words, if the processing circuit 41 can rotate the seat back 22 in the forward tilt direction Rf, it may set the target forward tilt angular velocity SPRfTr to a value different from the value obtained by inverting the sign of the target backward tilt angular velocity SPRrTr.

[0045] In the following step S29, the processing circuit 41 determines whether the tilt angle θ of the seat back 22 is less than or equal to the initial tilt angle θF. If the tilt angle θ is less than or equal to the initial tilt angle θF, it can be considered that the tilt angle θ has returned to the initial tilt angle θF. If the tilt angle θ is greater than the initial tilt angle θF (S29: NO), the processing circuit 41 proceeds to step S27. The processing circuit 41 then continues the degraded processing. On the other hand, if the tilt angle θ is less than or equal to the initial tilt angle θF (S29: YES), the processing circuit 41 proceeds to step S31.

[0046] In step S31, the processing circuit 41 terminates the degraded processing by functioning as the control unit 308. That is, the processing circuit 41 stops the rotation of the seat back 22. After that, the processing circuit 41 terminates the series of processes shown in Figure 4.

[0047] <Operation and Effects of This Embodiment> The operation and effects of this embodiment will be described with reference to Figures 5 and 6. For example, when the vehicle 10 is driving automatically using the autonomous driving function, if lateral acceleration occurs in the vehicle 10, the series of processes shown in Figure 4 are initiated. At this time, if the magnitude of the detected lateral acceleration value Gy is greater than the lateral acceleration threshold Gyth, a backward tilting process is executed, causing the seat back 22 to rotate in the backward tilting direction Rr.

[0048] As the seat back 22 begins to rotate in the backward direction Rr due to the backward tilting process, the support surface 22a of the seat back 22 separates from the back of the occupant 200, as shown in Figure 5. Even if the support surface 22a does not separate from the back, the normal force acting on the back from the support surface 22a decreases. When the posture of the seat 20 changes in this way, the balance of the occupant 200 sitting on the seat 20 is likely to be disrupted. At this time, the occupant 200 tries to maintain the posture of the occupant 200 before the posture of the seat 20 changed. Therefore, as shown in Figure 6, the occupant 200 braces itself. As a result, force is applied to the entire body of the occupant 200.

[0049] Here, when lateral acceleration occurs in the vehicle 10, such as when the vehicle 10 turns, the change in lateral acceleration causes the head 201 of the occupant 200 to shake, making the occupant 200 more susceptible to motion sickness.

[0050] In this regard, in the seat device 100, if the magnitude of the detected lateral acceleration value Gy is greater than the lateral acceleration threshold Gyth, a backward tilting process is performed. As a result, the seat back 22 rotates in the backward tilting direction Rr, which prompts the occupant 200 to brace themselves. When the occupant 200 braces themselves due to the rotation of the seat back 22, force is applied to the occupant 200's entire body. As a result, even if lateral acceleration is applied to the occupant 200, the shaking of the occupant 200's head 201 is suppressed. In this way, the seat device 100 can suppress motion sickness in the occupant 200 caused by lateral acceleration occurring in the vehicle 10.

[0051] Furthermore, it is not necessary to tilt the seat surface of the seat portion 21 of the seat 20. In other words, the seat device 100 does not need to be equipped with a dedicated actuator for tilting the seat surface. Therefore, an increase in the number of actuators in the seat device 100 can be suppressed, and consequently, an increase in cost and complexity of the configuration of the seat device 100 can be suppressed.

[0052] In this embodiment, the following effects (1-1) and (1-2) can be obtained. (1-1) The greater the lateral acceleration of the vehicle 10, the more likely the heads 201 of the occupants 200 are to sway laterally.

[0053] Therefore, in the seat device 100, if the magnitude of the detected lateral acceleration Gy is greater than the lateral acceleration threshold Gyth, the seat back 22 is rotated in the backward tilt direction Rr by a backward tilt process at an angular velocity greater than the reference backward tilt angular velocity SPRrB. When the seat back 22 is rotated in the backward tilt direction Rr by the backward tilt process, the larger the backward tilt angular velocity, the easier it is to make the occupant 200 brace themselves. By making the occupant 200 brace themselves, the lateral sway of the head 201 is reduced, thus increasing the effectiveness of suppressing motion sickness in the occupant 200 caused by the lateral acceleration generated in the vehicle 10.

[0054] (1-2) When the seat back 22 is rotated in the backward tilt direction Rr, the force exerted by the occupant will differ even at the same backward tilt angular velocity. In other words, it can be inferred that there are occupants who exert a force to brace themselves even at a relatively small backward tilt angular velocity, and occupants who do not exert a force to brace themselves at a relatively small backward tilt angular velocity.

[0055] Therefore, the seat device 100 sets a reference reclining angular velocity SPRrB based on occupant information. For example, if the occupant 200 is heavy, as can be estimated based on the occupant information, the reference reclining angular velocity SPRrB is calculated to be greater than when the occupant is lighter. In other words, during the reclining process, the seat back 22 rotates in the reclining direction Rr at a reclining angular velocity that takes the occupant information into account. This further enhances the suppression effect of motion sickness occurring in the occupant 200 due to the generation of lateral acceleration on the vehicle 10.

[0056] (Second Embodiment) A second embodiment of the sheet device will be described with reference to Figure 7. In the following description, the differences from the first embodiment will be mainly described, and the same reference numerals will be used for components that are the same as or equivalent to those in the first embodiment, and redundant explanations will be omitted.

[0057] Figure 7 shows a series of processes that are executed as subroutines while the back-tilting process is being performed. The processing circuit 41 is executed repeatedly while the back-tilting process is being performed. In step S101, the processing circuit 41, functioning as a prediction unit 306, determines whether or not it can predict the occurrence of sudden braking of the vehicle 10. If the processing circuit 41 can predict the occurrence of sudden braking (S101: YES), the processing circuit 41 proceeds to step S103. On the other hand, if the processing circuit 41 cannot predict the occurrence of sudden braking (S101: NO), that is, if the processing circuit 41 predicts that sudden braking will not occur, the processing circuit 41 terminates the series of processes.

[0058] In step S103, the processing circuit 41 functions as a control unit 308 and stops the seat back 22 from rotating in the backward tilt direction Rr by terminating the backward tilting process. In other words, the processing circuit 41 maintains the tilt angle θ.

[0059] In the following step S105, the processing circuit 41 determines whether the elapsed time TL from the point in time when the occurrence of emergency braking was predicted is less than or equal to the determination time TLth. The determination time TLth is a criterion for determining whether the time lag from the point in time when the occurrence of emergency braking was predicted to the actual occurrence of emergency braking is long or not. That is, if the elapsed time TL is less than or equal to the determination time TLth, it indicates that the time lag from the point in time when the occurrence of emergency braking was predicted to the actual occurrence of emergency braking is short and the situation is urgent. For example, if the occurrence of emergency braking was predicted because another vehicle suddenly cut in front of vehicle 10, the emergency braking will occur immediately after the prediction of emergency braking. The determination time TLth is set so that the elapsed time TL in such cases is less than or equal to the determination time TLth.

[0060] If the elapsed time TL is less than or equal to the determination time TLth (S105: YES), the processing circuit 41 proceeds to step S107. On the other hand, if the elapsed time TL is longer than the determination time TLth (S105: NO), the processing circuit 41 proceeds to step S111.

[0061] In step S107, the processing circuit 41 determines whether or not the vehicle 10 is undergoing sudden braking. If sudden braking is occurring (S107: YES), the processing circuit 41 proceeds to step S109. On the other hand, if sudden braking has not yet occurred (S107: NO), the processing circuit 41 proceeds to step S113.

[0062] In step S109, the processing circuit 41 determines whether or not the emergency braking has finished. If the emergency braking has not finished (S109: NO), the processing circuit 41 repeatedly executes the determination process in step S109 until the emergency braking is finished. If the emergency braking is finished (S109: YES), the processing circuit 41 proceeds to step S111.

[0063] In step S111, the processing circuit 41 performs a degradation process by functioning as a control unit 308. When the inclination angle θ returns to the initial inclination angle θF due to the execution of the degradation process, the processing circuit 41 terminates the degradation process. After that, the processing circuit 41 terminates the series of processes.

[0064] In step S113, the processing circuit 41 determines whether or not emergency braking is no longer necessary. The calculation of the collision margin time TM continues even after the occurrence of emergency braking is predicted. If the collision margin time TM becomes equal to or greater than the time determination value TMth after the occurrence of emergency braking is predicted, the processing circuit 41 can determine that emergency braking is no longer necessary. If the processing circuit 41 determines that emergency braking is no longer necessary (S113: YES), the processing circuit 41 proceeds to step S111. On the other hand, if the processing circuit 41 determines that emergency braking is not no longer necessary (S113: NO), the processing circuit 41 proceeds to step S105.

[0065] <Operation and Effects of This Embodiment> In this embodiment, in addition to the same effects and benefits as in the first embodiment described above, the effects and benefits shown in (2-1) and (2-2) below can be further obtained.

[0066] (2-1) If the tilt angle θ of the seat back 22 is too large when sudden braking occurs in the vehicle 10, the seat belt may not function correctly for the occupant 200. In the seat device 100 of this embodiment, if sudden braking of the vehicle 10 is predicted while the seat back 22 is rotating due to the execution of rear wheel processing, the rearward tilt processing is terminated. Furthermore, before sudden braking actually occurs, the tilt angle θ is returned to the initial tilt angle θF by executing a degradation processing. As a result, the seat device 100 can suppress the tilt angle θ from being too large when sudden braking occurs in the vehicle 10.

[0067] (2-2) If the seat back 22 rotates in the forward tilt direction Rf while emergency braking is actually occurring, the occupant 200 may feel uncomfortable. Therefore, in the seat device 100 of this embodiment, if the time lag from when emergency braking is predicted to occur until when emergency braking actually begins is less than or equal to a predetermined time TLth, the tilt angle θ is maintained during emergency braking, and then, when emergency braking ends, a degradation process is executed. As a result, discomfort to the occupant 200 due to the rotation of the seat back 22 during emergency braking can be suppressed.

[0068] (Example of change) The above embodiments can be implemented with the following modifications. The above embodiments and the following modifications can be combined with each other to the extent that they do not contradict each other technically.

[0069] In the second embodiment described above, even if the time lag between the prediction of sudden braking and the actual commencement of sudden braking is greater than or equal to a predetermined time TLth, the processing circuit 41 (i.e., the control unit 308) may wait to execute the degraded processing until the sudden braking is completed.

[0070] If sudden braking of the vehicle 10 is predicted while the seat back 22 is rotating in the rearward direction Rr due to the rearward tilting process, the processing circuit 41 (i.e., the control unit 308) may perform the degraded processing from before the end of the sudden braking, regardless of the length of the time lag between the prediction of sudden braking and the actual start of sudden braking.

[0071] The processing circuit 41 does not necessarily have to function as a prediction unit 306. In this case, if sudden braking occurs while the seat back 22 is rotating in the rearward direction Rr due to the rearward tilting process, it is preferable for the processing circuit 41 (i.e., the control unit 308) to terminate the rearward tilting process and maintain the tilt angle θ, and it is even more preferable to perform the degraded process after the sudden braking has ended.

[0072] Depending on the vehicle, the rear seats may be equipped with ottomans. In this case, if the processing circuit 41 (i.e., the control unit 308) predicts that the vehicle 10 will brake suddenly while the occupant 200 is using the ottoman, it may perform a degraded processing to return the tilt angle θ to the initial tilt angle θF and retract the ottoman.

[0073] In the second embodiment described above, the degraded processing performed because sudden braking is predicted does not need to return the tilt angle θ to the initial tilt angle θF. For example, if the range of tilt angles in which the seat belt can be properly operated is defined as the allowable angle range, the processing circuit 41 (i.e., the control unit 308) may, in the degraded processing, rotate the seat back 22 in the forward tilt direction Rf so that the tilt angle θ is within the allowable angle range.

[0074] If the actuator 30 overheats, the actuator 30 may stop operating while the seat back 22 is rotating due to the backward tilting process. In this case, the tilt angle θ is held at a position different from the initial tilt angle θF. In such cases, the processing circuit 41 may operate the actuator 30 to return the tilt angle θ to the initial tilt angle θF, provided that the temperature of the actuator 30 has cooled sufficiently and no braking is occurring in the vehicle 10.

[0075] The monitoring system of the vehicle 10 may include, for example, a weight detection sensor installed in the seat portion 21 of the seat 20. In this case, the processing circuit 41 may acquire the detected value of the sensor as occupant information and set the reference rear tilt angular velocity SPRrB taking this occupant information into consideration.

[0076] When the processing circuit 41 (i.e., the setting unit 304) calculates the reference rear tilt angular velocity SPRrB based on the magnitude of the longitudinal acceleration detection value Gx, it is not necessary to consider occupant information when setting the reference rear tilt angular velocity SPRrB.

[0077] In the above-described embodiments, the processing circuit 41 (i.e., the control unit 308) may perform the backward tilting process even if the magnitude of the detected lateral acceleration Gy is less than or equal to the lateral acceleration threshold Gyth, as long as a lateral acceleration is occurring in the vehicle 10. In this case, it is preferable for the processing circuit 41 to set the reference backward tilting angular velocity SPRrB to the target forward tilting angular velocity SPRfTr. This allows the processing circuit 41 to rotate the seat back 22 in the backward tilting direction Rr at the reference backward tilting angular velocity SPRrB.

[0078] The processing circuit 41 (i.e., the setting unit 304) may set the reference backward tilt angular velocity SPRrB so that it satisfies the following relation. In Figure 8, "K" indicates the center of rotation of the occupant 200 as the seat back 22 rotates in the backward tilt direction Rr. In the following relation, "m" is the weight of the occupant 200's upper body, and "m2" is the weight of the occupant 200's lower body. "Fn" is the normal force that the occupant 200 receives from the seat back 22. "Fs1" is the force in the seat direction that the occupant 200's chest receives from the seat belt, and "Fs2" is the force in the seat direction that the occupant 200's waist receives from the seat belt. "Fn2" is the normal force that the occupant 200 receives from the floor. "G1" is the force transmission gain by the abdominal muscles, and "G2" is the force transmission gain by the back muscles. "a" is the inertial component due to the longitudinal acceleration of the vehicle 10, and "g" is the acceleration due to gravity. "r" is the distance from point K to "Fs1", and "r2" is the distance from point K to Fs2. "r4" is the distance from point K to "m2", and "r5" is the distance from point K to "Fn2".

[0079]

number

[0080] In this case, the processing circuit 41 should substitute the longitudinal acceleration detection value Gx for "a" in the above relational equation. The processing circuit 41 (i.e., the control unit 308) may set the target tilt angular velocity SPRrTr to the sum of the reference tilt angular velocity SPRrB and a predetermined value when the magnitude of the detected lateral acceleration value Gy is greater than the lateral acceleration threshold Gyth.

[0081] The processing circuit 41 (i.e., the control unit 308) should perform a backward tilting process when lateral acceleration occurs in the vehicle 10 while the vehicle 10 is operating in automatic driving mode. Furthermore, when the vehicle 10 is operating in manual mode, the processing circuit 41 should perform a backward tilting process on the seats 20 for passengers other than the driver.

[0082] The processing circuit 41 is not limited to one that includes a CPU and ROM and executes software processing. In other words, the processing circuit 41 may have any of the following configurations: (a), (b), and (c).

[0083] (a) The processing circuit 41 comprises one or more processors that perform various processes according to a computer program. The processor includes a CPU and memory such as RAM and ROM. The memory stores program code or instructions configured to cause the CPU to perform the processes. The memory, i.e., computer-readable media, includes any available media that can be accessed by a general-purpose or dedicated computer.

[0084] (b) The processing circuit 41 includes one or more dedicated hardware circuits that perform various processes. Examples of dedicated hardware circuits include application-specific integrated circuits, i.e., ASICs or FPGAs. ASIC is an abbreviation for "Application Specific Integrated Circuit". FPGA is an abbreviation for "Field Programmable Gate Array".

[0085] (c) The processing circuit 41 comprises one or more processors that execute a portion of the various processes according to a computer program, and one or more dedicated hardware circuits that execute the remaining processes of the various processes. [Explanation of Symbols]

[0086] 10... Vehicles 20...sheets 21... Seat part 22... Seat back 30… Actuator 40…Control device 41…Processing circuit 61…Front and rear accelerometer 62...Lateral acceleration sensor 100... Sheet device 200... Crew 302... Crew Information Acquisition Unit 304...Settings section 306…Prediction Department 308... Control Unit

Claims

1. A seat device applied to a vehicle, comprising a longitudinal acceleration sensor for detecting the longitudinal acceleration of the vehicle and a lateral acceleration sensor for detecting the lateral acceleration of the vehicle, A seat having a seat portion and a seat back, An actuator for adjusting the tilt angle, which is the angle of the seat back relative to the seat portion, When the aforementioned lateral acceleration occurs in the vehicle, a control unit performs a backward tilting process that rotates the seat back in the backward tilting direction, which is the rotation direction of the seat back that increases the tilt angle. The system includes a setting unit that sets a reference rear tilt angular velocity based on the front-to-rear acceleration detection value, which is a value detected by the front-to-rear acceleration sensor, or a predetermined value. The control unit, In the backward tilting process when the magnitude of the lateral acceleration detection value, which is the value detected by the lateral acceleration sensor, is greater than a threshold, the seat back is rotated in the backward tilting direction at an angular velocity greater than the reference backward tilting angular velocity or a predetermined value. Seat device.

2. In the backward tilting process when the magnitude of the detected lateral acceleration is less than or equal to the threshold, the control unit rotates the seat back in the backward tilting direction at the reference backward tilting angular velocity. The sheet device according to claim 1.

3. The system includes an occupant information acquisition unit that acquires occupant information, which is information relating to the occupants seated in the aforementioned seats. The setting unit sets the reference rear tilt velocity based on the occupant information. The sheet device according to claim 1 or claim 2.

4. The vehicle is equipped with a prediction unit that predicts the occurrence of sudden braking, If the control unit predicts that the vehicle will suddenly brake while the rearward tilting process is being executed, it will terminate the rearward tilting process and perform a decompression process that rotates the seat back in the forward tilting direction, which is the opposite direction to the rearward tilting direction, so that the tilt angle approaches the angle before the rearward tilting process began. The sheet device according to claim 1.

5. If the control unit predicts the occurrence of sudden braking of the vehicle while the rearward tilting process is being executed, and the time lag between the prediction of sudden braking and the start of sudden braking is less than or equal to a predetermined time, the control unit terminates the rearward tilting process and maintains the tilt angle, and starts the deceleration process after the sudden braking has ended. The sheet device according to claim 4.

Images