Vehicle control device

Abstract

To suppress the increase of an absolute value of acceleration of a vehicle during changing of a vehicle speed when an occupant posture easily causes motion sickness.SOLUTION: A control device 70 comprises: an inclination angle acquisition unit 72 that acquires the head inclination angle of an occupant 200; an upper limit setting unit 74 that sets the upper limit value of the absolute value of acceleration of a vehicle; and an acceleration / deceleration control unit 75 that controls acceleration / deceleration of the vehicle so as to prevent the absolute value of the acceleration of the vehicle from exceeding the upper limit value. The upper limit setting unit 74 sets, when the head inclination angle is not within a prescribed angle range, a value smaller than when the head inclination angle is not within the prescribed angle range as the upper limit value.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present invention relates to a vehicle control device.

Background Art

[0002] Patent Document 1 describes an example of a vehicle control device that suppresses an increase in the vehicle's acceleration when it can be estimated that a vehicle occupant may be suffering from motion sickness. This control device estimates whether a vehicle occupant may be suffering from motion sickness based on the frequency of the acceleration of the occupant's head.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In ships and trains, it is known that passengers are prone to motion sickness when the frequency of acceleration is included in a specific frequency band. The specific frequency range is 0.2 Hz. On the other hand, in automobiles such as passenger cars, it is also known that the correlation between the frequency of the acceleration of the occupant's head and the susceptibility to motion sickness is low compared to ships and trains.

[0005] Therefore, in automobiles such as passenger cars, even if it is estimated whether a vehicle occupant may be suffering from motion sickness using the frequency of the head acceleration as in Patent Document 1, it is difficult to say that the estimation accuracy is high.

Means for Solving the Problems

[0006] A vehicle control device for solving the above problems includes an inclination angle acquisition unit that acquires a head inclination angle which is the inclination angle of the head of a vehicle occupant, an upper limit value setting unit that sets an upper limit value of the absolute value of the acceleration of the vehicle based on the head inclination angle, and an acceleration / deceleration control unit that controls the acceleration / deceleration of the vehicle so that the absolute value of the acceleration of the vehicle does not exceed the upper limit value. When the range of the head inclination angle at which the occupant is prone to motion sickness is defined as a specified angle range, the upper limit value setting unit sets a smaller value as the upper limit value when the head inclination angle is included in the specified angle range than when the head inclination angle is not included in the specified angle range.

[0007] The inventor of the present case has intensively studied the relationship between the posture of an occupant and the susceptibility of the occupant to motion sickness when the vehicle speed changes. As a result, the inventor obtained the knowledge that there is a certain degree of correlation between the head inclination angle of the occupant and the susceptibility of the occupant to motion sickness. Specifically, when the vehicle speed is changed while the head inclination angle is included in a predetermined inclination angle range, it was found that the occupant is more prone to motion sickness compared to the case where the vehicle speed is changed while the head inclination angle is not included in the predetermined inclination angle range.

[0008] Therefore, according to the above configuration, when the head inclination angle is included in the specified angle range, it can be determined that the occupant is prone to motion sickness. Therefore, a smaller value is set as the upper limit value than when the head inclination angle is not included in the specified angle range. The specified angle range is the range of the head inclination angle at which the occupant is prone to motion sickness. And when the vehicle is decelerated or accelerated, the acceleration / deceleration of the vehicle is controlled so that the absolute value of the acceleration of the vehicle does not exceed the upper limit value. Therefore, when the posture of the occupant is a posture prone to motion sickness, it is possible to suppress an increase in the absolute value of the acceleration of the vehicle when changing the vehicle speed.

Brief Description of the Drawings

[0009]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Mode for Carrying Out the Invention

[0010] Hereinafter, an embodiment of a vehicle control device will be described with reference to FIGS. 1 to 10. <Configuration of Vehicle 10> FIG. 1 shows a vehicle 10 equipped with a control device 70 of the present embodiment. The vehicle 10 includes a plurality of wheels 11 and a vehicle body 12. In the passenger compartment of the vehicle body 12, a plurality of seats 20 on which the occupants 200 of the vehicle 10 sit are provided. In the example shown in FIG. 1, each seat 20 is installed in the vehicle body 12 such that the front of the occupant 200 sitting on the seat 20 faces the front Xf of the vehicle.

[0011] As shown in FIGS. 1 and 2, when the occupant 200 sitting on the seat 20 is viewed from the lateral direction, the direction in which a virtual straight line extending from the ear to the nose of the occupant 200 extends is referred to as "occupant front Cf". When the occupant 200 faces upward or downward, the occupant front Cf changes. Therefore, the occupant front Cf is defined for each occupant 200.

[0012] As shown in FIG. 2, the vehicle 10 includes a drive device 16 and a braking device 17. The drive device 16 operates to adjust the driving force of the vehicle 10. The drive device 16 has a power source of the vehicle 10 such as an engine or an electric motor. The braking device 17 operates to adjust the braking force of the vehicle 10.

[0013] <Configuration of Seat 20> As shown in FIGS. 1 and 2, each seat 20 includes a seat portion 21, a seat back 22, and a headrest 23.

[0014] Among the seat back 22, the surface that touches the back of the occupant 200 sitting on the seat 20 is referred to as the seat back front surface 22a. The seat back 22 is rotatable with respect to the seat portion 21. That is, a rotation shaft 35 extending in the lateral direction of the vehicle 10 is provided on the seat portion 21. That is, the rotation shaft 35 extends in a direction orthogonal to both the vehicle front Xf and the vehicle upper Za. And the seat back 22 can rotate around the rotation shaft 35. In FIG. 2, the counterclockwise direction is defined as the forward tilt direction Rf, and the clockwise direction is defined as the rearward tilt direction Rr. At this time, by rotating the seat back 22 in the forward tilt direction Rf, the posture of the occupant 200 can be changed so that the occupant 200 tilts forward. Conversely, by rotating the seat back 22 in the rearward tilt direction Rr, the posture of the occupant 200 can be changed so that the occupant 200 tilts backward.

[0015] As shown in FIG. 2, each seat 20 includes a seat back tilting device 30. For example, the seat back tilting device 30 is disposed within the seat portion 21. The seat back tilting device 30 has a tilting actuator 31. The seat back tilting device 30 can rotate the seat back 22 in the forward tilt direction Rf or rotate the seat back 22 in the rearward tilt direction Rr by the operation of the tilting actuator 31. That is, by the operation of the tilting actuator 31, the posture of the occupant 200 sitting on the seat 20 can be changed.

[0016] <Electrical Configuration of Vehicle 10> As shown in FIG. 2, the vehicle 10 is provided with an occupant monitoring system 51 that monitors the occupant 200. The occupant monitoring system 51 transmits information regarding the monitoring result of the occupant 200 to the control device 70.

[0017] For example, the occupant monitoring system 51 has an imaging device such as a camera that images the occupant 200. By analyzing the image captured by the imaging device, it is possible to determine whether the occupant 200 is reading. Also, by analyzing the image, it is possible to determine whether the occupant 200 is looking at the image displayed on the screen of the mobile terminal owned by the occupant 200. Examples of the mobile terminal include a smartphone and a tablet terminal.

[0018] Road information, which is information regarding the road on which the vehicle 10 travels, is input to the control device 70 from the navigation device 52. The road information includes, for example, information regarding whether the road on which the vehicle 10 is traveling is a highway. Note that the navigation device 52 may be an in-vehicle navigation device or a mobile terminal having a navigation function.

[0019] Detection signals of various sensors are input to the control device 70. Examples of the sensors include a longitudinal acceleration sensor 61 and a vehicle speed sensor 62. The longitudinal acceleration sensor 61 detects the longitudinal acceleration Gx of the vehicle 10 and outputs a detection signal according to the detection result. The vehicle speed sensor 62 detects the vehicle speed Vs, which is the traveling speed of the vehicle 10, and outputs a detection signal according to the detection result.

[0020] The control device 70 includes a CPU, a ROM, and a storage device. Various control programs executed by the CPU are stored in the ROM. The operation results of the CPU and the like are stored in the storage device.

[0021] The control device 70 has a seat control unit 71 as a functional unit. The seat control unit 71 controls the seat back tilting device 30 of each seat 20. That is, the seat control unit 71 adjusts the seat back tilt angle, which is the tilt angle of the seat back 22 with respect to the seat portion 21, by controlling the seat back tilting device 30.

[0022] The control device 70 has an inclination angle acquisition unit 72 as a functional unit. The inclination angle acquisition unit 72 acquires the head inclination angle θf, which is the inclination angle of the head 201 of the occupant 200. For example, the inclination angle acquisition unit 72 can acquire the head inclination angle θf based on the posture of the seat 20 on which the occupant 200 is seated. In this case, the inclination angle acquisition unit 72 may estimate the inclination angle of the head 201 of the occupant 200 based on the seat back tilt angle and acquire the estimated value of the inclination angle of the head 201 as the head inclination angle θf.

[0023] Here, referring to FIGS. 3 and 4, the head inclination angle θf will be described. In FIGS. 3 and 4, a reference line Lb is shown by a two-dot chain line. The reference line Lb is a straight line extending in a direction orthogonal to the road surface on which the vehicle 10 travels. When the direction approaching the road surface among the two directions along the reference line Lb is defined as the "approach direction Db", the angle formed by the approach direction Db and the front of the occupant Cf is the head inclination angle θf. As shown in FIG. 3, when the front of the occupant Cf coincides with the front of the vehicle Xf, the head inclination angle θf is 90°. As shown in FIG. 4, when the face of the occupant 200 is facing downward, the head inclination angle θf is smaller than 90°. On the contrary, when the face of the occupant 200 is facing upward, the head inclination angle θf is larger than 90°. That is, the smaller the head inclination angle θf becomes as the posture of the occupant 200 inclines forward.

[0024] Therefore, when acquiring the head inclination angle θf based on the seat back tilt angle, the inclination angle acquisition unit 72 may acquire a smaller value as the head inclination angle θf as the seat back 22 rotates in the forward tilt direction Rf. On the other hand, the inclination angle acquisition unit 72 may acquire a larger value as the head inclination angle θf as the seat back 22 rotates in the rearward tilt direction Rr.

[0025] Returning to FIG. 2, the control device 70 has a condition determination unit 73 as a functional unit. The condition determination unit 73 determines whether or not a predetermined decrease correction condition is satisfied. When at least one of the following conditions (A1) and (A2) is satisfied, the condition determination unit 73 determines that the decrease correction condition is satisfied. (A1) The occupant 200 is looking at an image. (A2) The occupant 200 is reading a book.

[0026] For example, the condition determination unit 73 can determine whether or not the decrease correction condition is satisfied based on the information regarding the monitoring result of the occupant 200 transmitted from the occupant monitoring system 51. The control device 70 has an upper limit value setting unit 74 as a functional unit. The upper limit value setting unit 74 sets an upper limit value GxL of the absolute value of the longitudinal acceleration Gx of the vehicle 10 based on the head tilt angle θf. Further, when it is determined that the decrease correction condition is satisfied, the upper limit value setting unit 74 sets a smaller value as the upper limit value GxL than when it is not determined that the decrease correction condition is satisfied.

[0027] The control device 70 has an acceleration / deceleration control unit 75 as a functional unit. The acceleration / deceleration control unit 75 controls the acceleration / deceleration of the vehicle 10 so that the absolute value of the longitudinal acceleration Gx does not exceed the upper limit value GxL. Such an acceleration / deceleration control unit 75 includes a drive control unit 751 and a braking control unit 752.

[0028] The drive control unit 751 controls the drive device 16. For example, when accelerating the vehicle 10, the drive control unit 751 controls the drive device 16 so that the acceleration of the vehicle 10 does not exceed the upper limit value GxL.

[0029] The braking control unit 752 controls the braking device 17. For example, when decelerating the vehicle 10, the braking control unit 752 controls the braking device 17 so that the deceleration of the vehicle 10 does not exceed the upper limit value GxL.

[0030] When the control device 70 operates the vehicle 10 in the automatic driving mode as a functional unit, it has an automatic driving control unit 76 that instructs acceleration and deceleration of the vehicle 10. The automatic driving mode is a mode in which the vehicle 10 can be driven without the occupant 200 performing an accelerator operation, a brake operation, or a steering operation. When the vehicle 10 is accelerated automatically while running in the automatic driving mode, the automatic driving control unit 76 derives an acceleration instruction value GxBR that is an instruction value for the acceleration of the vehicle 10. On the other hand, when the vehicle 10 is decelerated automatically while running in the automatic driving mode, the automatic driving control unit 76 derives a deceleration instruction value GxAR that is an instruction value for the deceleration of the vehicle 10.

[0031] <Mechanism by which the occupant 200 gets carsick> When the acceleration and deceleration of the vehicle 10 are repeated, the occupant 200 may get carsick. Therefore, the mechanism by which the occupant 200 gets carsick due to the occurrence of acceleration and deceleration in the vehicle 10 will be described.

[0032] The inventor of the present application conducted intensive research on the relationship between the direction of the acceleration acting on the head 201 of the occupant 200 and the susceptibility of the occupant 200 to carsickness. As a result, the finding was obtained that the susceptibility to carsickness changes depending on the direction of the acceleration acting on the head 201.

[0033] Next, the experiment conducted to obtain such findings will be described. The acceleration and deceleration of the vehicle 10 are repeated so that the vehicle speed Vs varies in the range of 10 km / h to 40 km / h. Then, the subject 200C riding in the vehicle 10 gives an evaluation score according to the degree of discomfort felt during the running of the vehicle 10. Specifically, the subject 200C gives an evaluation score such that the value increases as the degree of discomfort increases.

[0034] When conducting the experiment as described above, the subject 200C is made to take a plurality of postures shown in FIG. 5. (First posture Pos1) The subject 200C is made to take a forward-leaning posture, and the head tilt angle θf is set to 0°. (Second Posture Pos2) Make Subject 200C assume a forward-leaning posture and set the head tilt angle θf to 40°. (Third Posture Pos3) Make the posture of Subject 200C an upright posture and set the head tilt angle θf to 90°. (Fourth Posture Pos4) Make Subject 200C assume a backward-leaning posture and set the head tilt angle θf to 150°. (Fifth Posture Pos5) Make Subject 200C assume a backward-leaning posture and set the head tilt angle θf to 180°.

[0035] When the vehicle 10 is driven as described above with the posture of Subject 200C being the first posture Pos1, Subject 200C gives points as evaluation points according to the degree of discomfort felt by Subject 200C. When the vehicle 10 is driven with the posture of Subject 200C being the second posture Pos2, Subject 200C gives points as evaluation points according to the degree of discomfort felt by Subject 200C. When the vehicle 10 is driven with the posture of Subject 200C being the third posture Pos3, Subject 200C gives points as evaluation points according to the degree of discomfort felt by Subject 200C. When the vehicle 10 is driven with the posture of Subject 200C being the fourth posture Pos4, Subject 200C gives points as evaluation points according to the degree of discomfort felt by Subject 200C. When the vehicle 10 is driven with the posture of Subject 200C being the fifth posture Pos5, Subject 200C gives points as evaluation points according to the degree of discomfort felt by Subject 200C.

[0036] The results of the evaluation are shown in FIG. 6. The susceptibility to motion sickness index IND is a quantification of the susceptibility to motion sickness in a vehicle. The higher the above evaluation points, the larger the susceptibility to motion sickness index IND. Therefore, the larger the susceptibility to motion sickness index IND, the easier it is to get motion sickness. As is also clear from FIG. 6, when Subject 200C rides in the second posture Pos2, Subject 200C is most susceptible to motion sickness. When Subject 200C rides in the third posture Pos3, Subject 200C is second most susceptible to motion sickness. That is, it was found that Subject 200C is susceptible to motion sickness when the posture of Subject 200C is around the second posture Pos2.

[0037] When the experiment was further advanced in more detail, it was found that when the head tilt angle θf is 35° or more and 85° or less, the subject 200C is most likely to get motion sickness.

[0038] Based on these results, in the present embodiment, when the range of the head tilt angle θf that is likely to cause motion sickness is defined as the defined angle range Rθf, the range of the head tilt angle θf from 35° to 85° is set as the defined angle range Rθf. In this case, 35° corresponds to the lower limit θfb1 of the defined angle range Rθf, and 85° corresponds to the upper limit θfb2 of the defined angle range Rθf.

[0039] <Flow of processing executed by the control device 70> With reference to FIG. 7, a series of processing flows executed by the control device 70 when the vehicle 10 travels in the automatic driving mode will be described.

[0040] In a series of processing, in the first step S11, the tilt angle acquisition unit 72 of the control device 70 acquires the head tilt angle θf of the occupant 200. When a plurality of occupants 200 are riding in the vehicle 10, the tilt angle acquisition unit 72 acquires the head tilt angle θf of each occupant 200.

[0041] Subsequently, in step S13, the upper limit value setting unit 74 of the control device 70 sets the upper limit value GxL. That is, when the head tilt angle θf acquired in step S11 is included in the defined angle range Rθf, the upper limit value setting unit 74 sets a smaller value as the upper limit value GxL than when the head tilt angle θf is not included in the defined angle range Rθf.

[0042] When the head tilt angle θf is not included in the specified angle range Rθf, the upper limit value setting unit 74 may set as follows. For example, when the head tilt angle θf is smaller than the lower limit θfb1 of the specified angle range Rθf, the upper limit value setting unit 74 sets a larger value as the upper limit value GxL as the head tilt angle θf becomes smaller. Also, for example, when the head tilt angle θf is larger than the upper limit θfb2 of the specified angle range Rθf, the upper limit value setting unit 74 sets a larger value as the upper limit value GxL as the head tilt angle θf becomes larger.

[0043] When setting the upper limit value GxL based on the head tilt angle θf, the upper limit value setting unit 74 may use the map shown in FIG. 8. FIG. 8 shows a map indicating the relationship between the head tilt angle θf and the upper limit value GxL. In this map, when the head tilt angle θf is equal to the intermediate value θfb of the specified angle range Rθf, the upper limit value GxL becomes the minimum value. The intermediate value θfb is a head tilt angle θf that is smaller than the upper limit θfb2 and larger than the lower limit θfb1. For example, the intermediate value θfb is the head tilt angle θf right in the middle of the specified angle range Rθf.

[0044] In the map shown in FIG. 8, when the head tilt angle θf is smaller than the intermediate value θfb, the upper limit value GxL increases as the head tilt angle θf becomes smaller. On the other hand, when the head tilt angle θf is larger than the intermediate value θfb, when the head tilt angle θf is less than or equal to the predetermined tilt angle θfa, the upper limit value GxL increases as the head tilt angle θf becomes larger. When the head tilt angle θf is larger than the predetermined tilt angle θfa, the upper limit value GxL decreases as the head tilt angle θf becomes larger.

[0045] Incidentally, as the predetermined tilt angle θfa, an angle of 150° or more and less than 180° is set. For example, it is advisable to set 150° as the predetermined tilt angle θfa. This is because, as shown in FIG. 6, when the head tilt angle θf is 150°, the drunkenness index IND becomes the minimum.

[0046] Here, there may be a plurality of passengers 200 in the vehicle 10. In this case, the upper limit value setting unit 74 may set, as the upper limit value GxL, a value corresponding to the head tilt angle θf that is closest to the reference tilt angle among the head tilt angles θf of each passenger 200. The reference tilt angle is the intermediate value θfb.

[0047] Returning to FIG. 7, when the upper limit value GxL is set in step S13, the control device 70 shifts the process to step S15. In step S15, the condition determination unit 73 of the control device 70 determines whether or not the above-described decrease correction condition is satisfied. If it is determined that the decrease correction condition is satisfied (S15: YES), the control device 70 shifts the process to step S17. In step S17, the upper limit value setting unit 74 of the control device 70 performs a decrease correction on the upper limit value GxL set in step S13. For example, the upper limit value setting unit 74 sets, as the new upper limit value GxL, a value obtained by subtracting the correction value α from the upper limit value GxL set in step S13. Then, the control device 70 shifts the process to step S19. In this case, a positive value is set as the correction value α.

[0048] On the other hand, in step S15, if it is not determined that the decrease correction condition is satisfied (NO), the control device 70 shifts the process to step S19. That is, when it is not determined that the decrease correction condition is satisfied, the decrease correction of the upper limit value GxL is not performed. Therefore, the upper limit value setting unit 74 sets, as the upper limit value GxL, a value smaller than that when it is determined that the decrease correction condition is satisfied, when it is not determined that the decrease correction condition is satisfied.

[0049] In step S19, the control device 70 determines whether the vehicle 10 is traveling on a predetermined road. For example, the predetermined road is a highway. When the vehicle 10 is traveling on the highway, the vehicle speed Vs does not change as compared with the case where the vehicle 10 is traveling on a road other than the highway. Therefore, when the vehicle 10 is traveling on the highway, the upper limit value GxL does not have to be made too small. Thus, when the vehicle 10 is traveling on the predetermined road (S19: YES), the control device 70 shifts the process to step S21.

[0050] In step S21, the upper limit value setting unit 74 of the control device 70 increases and corrects the upper limit value GxL. For example, the upper limit value setting unit 74 sets the sum of the upper limit value GxL and the correction value β as the new upper limit value GxL. A positive value is set as the correction value β. For example, the correction value β may be the same value as the above-described correction value α, or may be a value different from the correction value α. Then, the control device 70 shifts the process to step S23.

[0051] On the other hand, in step S19, when the vehicle 10 is not traveling on the predetermined road (NO), the control device 70 shifts the process to step S23. That is, when the vehicle 10 is traveling on a road other than the highway (for example, an ordinary road or a mountain road), the upper limit value GxL is not increased and corrected. Therefore, the upper limit value setting unit 74 sets a larger value as the upper limit value GxL when the vehicle 10 is traveling on the highway than when the vehicle 10 is traveling on a road other than the highway.

[0052] In step S23, the acceleration / deceleration control unit 75 of the control device 70 determines whether it has been instructed by the automatic driving control unit 76 to decelerate the vehicle 10. When there is an instruction to decelerate (S23: YES), the acceleration / deceleration control unit 75 shifts the process to step S25. In step S25, the braking control unit 752 of the acceleration / deceleration control unit 75 performs braking control to operate the braking device 17 and control the braking force of the vehicle 10.

[0053] When deceleration is instructed, the braking control unit 752 controls the deceleration of the vehicle 10 based on the deceleration instruction value GxAR derived by the automatic driving control unit 76 and the upper limit value GxL set by the upper limit value setting unit 74. That is, when decelerating the vehicle 10, the braking control unit 752 increases the deceleration of the vehicle 10 to the deceleration instruction value GxAR when the absolute value of the deceleration instruction value GxAR is less than or equal to the upper limit value GxL. On the other hand, when the absolute value of the deceleration instruction value GxAR is greater than the upper limit value GxL, the braking control unit 752 increases the deceleration of the vehicle 10 to the upper limit value GxL.

[0054] From the perspective of suppressing the vehicle sickness of the occupant 200, it is desirable not to suddenly increase the deceleration of the vehicle 10. Therefore, when the absolute value of the deceleration instruction value GxAR is less than or equal to the upper limit value GxL, the braking control unit 752 may control the braking device 17 so that the deceleration of the vehicle 10 increases gradually. On the other hand, when the absolute value of the deceleration instruction value GxAR is greater than the upper limit value GxL, the deceleration of the vehicle 10 cannot be increased to the deceleration instruction value GxAR. Therefore, it is desirable to quickly increase the deceleration of the vehicle 10 to the upper limit value GxL. Thus, when the absolute value of the deceleration instruction value GxAR is greater than the upper limit value GxL, the braking control unit 752 may control the braking device 17 so that the increasing speed of the deceleration of the vehicle 10 becomes large. Thereby, when the absolute value of the deceleration instruction value GxAR is less than or equal to the upper limit value GxL, the braking control unit 752 can make the increasing speed of the deceleration of the vehicle 10 before the deceleration of the vehicle 10 reaches the deceleration instruction value GxAR smaller than when the absolute value of the deceleration instruction value GxAR is greater than the upper limit value GxL.

[0055] The braking control unit 752 performs braking control until the vehicle speed Vs reaches the desired vehicle speed. When the execution of the braking control is completed, the control device 70 ends a series of processes. On the other hand, in step S23, when there is no deceleration instruction (NO), the acceleration / deceleration control unit 75 transfers the process to step S27. In step S27, the acceleration / deceleration control unit 75 determines whether an acceleration instruction for the vehicle 10 is given from the automatic driving control unit 76. When there is an acceleration instruction (S27: YES), the acceleration / deceleration control unit 75 transfers the process to step S29. In step S29, the drive control unit 751 of the acceleration / deceleration control unit 75 performs drive control to operate the drive device 16 and control the driving force of the vehicle 10.

[0056] When acceleration is instructed, the drive control unit 751 controls the acceleration of the vehicle 10 based on the acceleration instruction value GxBR derived by the automatic driving control unit 76 and the upper limit value GxL set by the upper limit value setting unit 74. That is, when accelerating the vehicle 10, the drive control unit 751 increases the acceleration of the vehicle 10 to the acceleration instruction value GxBR when the absolute value of the acceleration instruction value GxBR is less than or equal to the upper limit value GxL. On the other hand, when the absolute value of the acceleration instruction value GxBR is greater than the upper limit value GxL, the drive control unit 751 increases the acceleration of the vehicle 10 to the upper limit value GxL.

[0057] From the perspective of suppressing the vehicle sickness of the passenger 200, it is desirable to prevent the acceleration of the vehicle 10 from increasing suddenly. Therefore, when the absolute value of the acceleration command value GxBR is equal to or less than the upper limit value GxL, the drive control unit 751 may control the drive device 16 so that the acceleration of the vehicle 10 increases gradually. On the other hand, when the absolute value of the acceleration command value GxBR is greater than the upper limit value GxL, the acceleration of the vehicle 10 cannot be increased up to the acceleration command value GxBR. Therefore, it is desirable to quickly increase the acceleration of the vehicle 10 up to the upper limit value GxL. Thus, when the absolute value of the acceleration command value GxBR is greater than the upper limit value GxL, the brake control unit 752 may control the drive device 16 so that the increasing speed of the acceleration of the vehicle 10 becomes greater. Thereby, when the absolute value of the acceleration command value GxBR is equal to or less than the upper limit value GxL, the drive control unit 751 can make the increasing speed of the acceleration of the vehicle 10 until the acceleration of the vehicle 10 reaches the acceleration command value GxBR smaller compared to the case where the absolute value of the acceleration command value GxBR is greater than the upper limit value GxL.

[0058] The drive control unit 751 performs drive control until the vehicle speed Vs reaches the desired vehicle speed. When the execution of the drive control ends, the control device 70 ends a series of processes. On the other hand, in step S27, when there is no acceleration instruction (NO), the control device 70 ends a series of processes without executing step S29.

[0059] Note that the control of the acceleration and deceleration of the vehicle 10 based on the upper limit value GxL as described above must be implemented on the premise that the safety of the vehicle 10 is ensured. For example, in the case of emergency braking for the purpose of avoiding a collision with a preceding vehicle, it is natural that the braking control is implemented without considering the upper limit value GxL.

[0060] <Actions and Effects in this Embodiment> When the head tilt angle θf is included in the specified angle range Rθf, it can be determined that the occupant 200 is prone to motion sickness. Therefore, in such a case, a value smaller than when the head tilt angle θf is not included in the specified angle range Rθf is set as the upper limit value GxL. When decelerating the vehicle 10, the braking device 17 is controlled so that the deceleration of the vehicle 10 does not exceed the upper limit value GxL. When accelerating the vehicle 10, the drive device 16 is controlled so that the acceleration of the vehicle 10 does not exceed the upper limit value GxL. That is, when the posture of the occupant 200 is a posture prone to motion sickness, it is possible to suppress an increase in the absolute value of the acceleration of the vehicle 10 when changing the vehicle speed Vs. Thereby, it is possible to suppress the occupant 200 from suffering from motion sickness.

[0061] Figures 9 and 10 show the transition of the deceleration GxA of the vehicle 10 when deceleration of the vehicle 10 is instructed. Figure 9 shows the case where the absolute value of the deceleration instruction value GxAR is larger than the upper limit value GxL. Figure 10 shows the case where the absolute value of the deceleration instruction value GxAR is less than or equal to the upper limit value GxL.

[0062] In the example shown in Figure 9, deceleration of the vehicle 10 is instructed at timing t11. In this case, since the absolute value of the deceleration instruction value GxAR is larger than the upper limit value GxL, the deceleration GxA cannot be increased to the deceleration instruction value GxAR. Therefore, the increasing speed of the deceleration GxA is large. As a result, at timing t12, the deceleration GxA reaches the upper limit value GxL. After timing t12, the deceleration GxA is maintained at the upper limit value GxL. The time from timing t11 to timing t12 is defined as the deceleration control time TM1.

[0063] In the example shown in FIG. 10, deceleration of the vehicle 10 is instructed at timing t21. In this case, since the absolute value of the deceleration instruction value GxAR is smaller than the upper limit value GxL, the deceleration GxA can be increased to the deceleration instruction value GxAR. Therefore, the increase rate of the deceleration GxA is small. As a result, at timing t22, the deceleration GxA reaches the deceleration instruction value GxAR. Then, after timing t22, the deceleration GxA is maintained at the deceleration instruction value GxAR. The time from timing t21 to timing t22 is defined as deceleration control time TM2. The deceleration control time TM2 is longer than the deceleration control time TM1.

[0064] That is, according to the present embodiment, when the absolute value of the deceleration instruction value GxAR is less than or equal to the upper limit value GxL, the deceleration GxA is gently increased. As a result, it is possible to suppress the passenger 200 from getting motion sickness due to a sudden change in the deceleration GxA.

[0065] Incidentally, when the braking control or the driving control is started, the upper limit value GxL is held at the value at the start point of the control. Therefore, the upper limit value GxL during the braking control or the driving control is held at a value based on the posture of the passenger 200 at the start point of the control.

[0066] With reference to FIGS. 9 and 10, the operations and effects when deceleration of the vehicle 10 is instructed have been described. The operations and effects when acceleration of the vehicle 10 is instructed are substantially the same as those when deceleration of the vehicle 10 is instructed. Therefore, the description of the operations and effects when acceleration of the vehicle 10 is instructed is omitted here.

[0067] In the present embodiment, the following effects can be further obtained. (1) In this embodiment, when decelerating the vehicle 10, even if the head tilt angle θf at the start of deceleration is not within the specified angle range Rθf, the upper limit value GxL changes depending on the head tilt angle θf at the start of deceleration or acceleration. Specifically, a larger value is set as the upper limit value GxL to the extent that it can be estimated that the occupant 200 is less likely to get motion sickness. The larger the upper limit value GxL, the less likely it is that restrictions are imposed on the deceleration GxA or acceleration of the vehicle 10. That is, when the posture of the occupant 200 is a posture in which it is difficult to get motion sickness, it becomes less likely that restrictions are imposed on the deceleration GxA or acceleration of the vehicle 10.

[0068] (2) When the occupant 200 is reading or looking at an image, it can be inferred that the occupant 200 is more likely to get motion sickness compared to when not doing so. Therefore, in this embodiment, when the occupant 200 is reading or looking at an image, a smaller value is set as the upper limit value GxL than when not doing so. Thereby, when the occupant 200 is reading or looking at an image, it is possible to suppress an increase in the deceleration GxA or acceleration of the vehicle 10.

[0069] (3) When the vehicle 10 is traveling on a highway, it can be inferred that the vehicle speed Vs does not change very much. Therefore, a larger value is set as the upper limit value GxL than when the vehicle 10 is traveling on a road other than a highway. Thereby, when the vehicle 10 is traveling on a highway, the deceleration GxA or acceleration of the vehicle 10 can be increased as necessary.

[0070] (4) When a plurality of occupants 200 are on board the vehicle 10, the upper limit value GxL is set based on the head tilt angle θf that is closest to the median value θfb among the head tilt angles θf of the respective occupants 200. That is, the upper limit value GxL is set based on the head tilt angle θf of the occupant 200 in the posture most likely to get motion sickness. By controlling the acceleration and deceleration of the vehicle 10 based on such an upper limit value GxL, it is possible to suppress each occupant 200 from getting motion sickness.

[0071] (5) In this embodiment, based on the posture of the seat 20, the head tilt angle θf of the occupant 200 is acquired. Therefore, it is not necessary to provide a dedicated detection system for acquiring the head tilt angle θf in the vehicle 10.

[0072] <Modification example> The above embodiment can be implemented with the following modifications. The above embodiment and the following modification examples can be implemented in combination with each other within a technically consistent range.

[0073] · In the above embodiment, when a plurality of occupants 200 are in the vehicle 10, the head tilt angles θf of all the occupants 200 are acquired, but it is not limited to this. For example, among the plurality of occupants 200, only the head tilt angles θf of some of the occupants 200 may be acquired. For example, the head tilt angle θf of the occupant 200 sitting on a seat other than the driver's seat may be acquired, and it may not be necessary to acquire the head tilt angle θf of the occupant 200 sitting on the driver's seat.

[0074] · When an imaging device for imaging the occupant 200 is provided inside the vehicle, the head tilt angle θf of the occupant 200 may be acquired by analyzing the image captured by the imaging device. · When the head tilt angles θf of a plurality of occupants 200 are acquired, the upper limit value GxL is set based on the head tilt angle θf closest to the reference tilt angle, but it is not limited to this. For example, the upper limit value GxL may be set based on the head tilt angle θf second closest to the reference tilt angle.

[0075] · When driving on a mountain road, it is presumed that the occupant 200 is prone to motion sickness. Therefore, when the vehicle 10 is driving on a road other than an expressway, when the vehicle 10 is driving on a mountain road, a smaller value may be set as the upper limit value GxL than when the vehicle 10 is driving on a road that is not a mountain road.

[0076] · It is not necessary to vary the upper limit value GxL according to the road on which the vehicle 10 is driving. ·For example, when an image other than a map is displayed on the display of the in-vehicle navigation device as in the case where a DVD is being played on the in-vehicle navigation device, there is a possibility that the occupant 200 is looking at the image. Therefore, when an image other than a map is displayed on the display of the navigation device, it may be determined that the reduction correction condition is satisfied.

[0077] ·The upper limit value GxL may not be varied according to the determination result as to whether or not the reduction correction condition is satisfied. ·Whether or not the absolute value of the deceleration instruction value GxAR is greater than the upper limit value GxL may not be used to vary the increasing speed of the deceleration GxA of the vehicle 10.

[0078] ·Whether or not the absolute value of the acceleration instruction value GxBR is greater than the upper limit value GxL may not be used to vary the increasing speed of the acceleration of the vehicle 10. ·In the above embodiment, when the head tilt angle θf is included in the specified angle range Rθf, the upper limit value GxL changes according to the head tilt angle θf, but it is not limited to this. When the head tilt angle θf is included in the specified angle range Rθf, the upper limit value GxL may be fixed at the first value.

[0079] ·In the above embodiment, when the head tilt angle θf is not included in the specified angle range Rθf, the upper limit value GxL changes according to the head tilt angle θf, but it is not limited to this. When the head tilt angle θf is not included in the specified angle range Rθf, the upper limit value GxL may be fixed at the second value.

[0080] ·When acceleration or deceleration of the vehicle 10 is instructed in a situation where the head tilt angle θf of the occupant 200 is included in the specified angle range Rθf, the seat back 22 of the seat 20 may be automatically rotated so that the head tilt angle θf is outside the specified angle range Rθf. In this case, it is preferable to return the seat back tilt angle to its original state when the acceleration or deceleration of the vehicle 10 ends.

[0081] ·As the upper limit value GxL, the upper limit value for decelerating the vehicle 10 and the upper limit value for accelerating the vehicle 10 may be set separately. ·In the above embodiment, the range from 35° to 85° is defined as the specified angle range Rθf, but this is just an example. If the vehicle type, and the shape and cushioning property of the seat are different, the range of the head tilt angle θf at which the occupant 200 is likely to get motion sickness may vary slightly.

[0082] ·The control device 70 may have any of the following configurations (a) to (c). (a) The control device 70 includes one or more processors that execute various processes according to a computer program. The processor includes a CPU and memories such as a RAM and a ROM. The memory stores program codes or instructions configured to cause the CPU to execute the processes. The memory, that is, the computer-readable medium, includes any available medium accessible by a general-purpose or dedicated computer. (b) The control device 70 includes one or more dedicated hardware circuits that execute various processes. Examples of the dedicated hardware circuit include an application-specific integrated circuit, that is, an ASIC or an FPGA. Note that ASIC is an abbreviation for "Application Specific Integrated Circuit". FPGA is an abbreviation for "Field Programmable Gate Array". (c) The control device 70 includes a processor that executes some of the various processes according to a computer program and a dedicated hardware circuit that executes the remaining processes of the various processes.

[0083] Next, the technical idea that can be grasped from the above embodiment and modification example will be described. (i) When the occupant is viewed from the lateral direction, the direction in which a straight line extending from the ear to the nose of the occupant extends is defined as the front of the occupant, and when, of the two directions along a straight line orthogonal to the road surface on which the vehicle travels, the direction approaching the road surface is defined as the approaching direction, The tilt angle acquisition unit acquires the angle formed between the front of the occupant and the approaching direction as the head tilt angle, A range of the head tilt angle from 35° to 85° is set as the specified angle range.

Explanation of Signs

[0084] 10…Vehicle 20…Seat 70…Control device 72…Tilt angle acquisition unit 73…Condition determination unit 74…Upper limit value setting unit 75…Acceleration / deceleration control unit 751…Drive control unit 752…Brake control unit 76…Autonomous driving control unit 200…Occupant 201…Head

Claims

1. An inclination angle acquisition unit that acquires a head inclination angle, which is the inclination angle of the head of a vehicle occupant; An upper limit value setting unit that sets an upper limit value of the absolute value of the acceleration of the vehicle based on the head inclination angle; A acceleration / deceleration control unit that controls the acceleration and deceleration of the vehicle so that the absolute value of the acceleration of the vehicle does not exceed the upper limit value, and When the range of the head inclination angle at which motion sickness is likely to occur is defined as a specified angle range, the upper limit value setting unit sets a smaller value as the upper limit value when the head inclination angle is included between the lower limit and the upper limit of the specified angle range than when the head inclination angle is not included between the lower limit and the upper limit of the specified angle range A control device for a vehicle.

2. The head inclination angle becomes smaller as the posture of the occupant inclines forward, The upper limit value setting unit when the head inclination angle is greater than the upper limit of the specified angle range, sets a larger value as the upper limit value as the head inclination angle is larger, when the head inclination angle is smaller than the lower limit of the specified angle range, sets a larger value as the upper limit value as the head inclination angle is smaller, and the inclination angle acquisition unit acquires the head inclination angles of a plurality of the occupants when a plurality of the occupants are on board the vehicle, when the intermediate value of the specified angle range is defined as a reference inclination angle, the upper limit value setting unit sets the upper limit value based on the head inclination angle among the head inclination angles of the plurality of the occupants that is closest to the reference inclination angle when a plurality of the occupants are on board the vehicle The vehicle control device according to claim 1.

3. When the vehicle is traveling in an automatic driving mode, it includes an automatic driving control unit that instructs acceleration and deceleration of the vehicle, the automatic driving control unit derives a deceleration instruction value, which is an instruction value of the deceleration of the vehicle, when decelerating the vehicle traveling in the automatic driving mode, when decelerating the vehicle, the acceleration / deceleration control unit increases the deceleration of the vehicle to the deceleration instruction value when the absolute value of the deceleration instruction value is less than or equal to the upper limit value, while increasing the deceleration of the vehicle to the upper limit value when the absolute value of the deceleration instruction value is greater than the upper limit value, and the acceleration / deceleration control unit makes the increase speed of the deceleration of the vehicle until the deceleration of the vehicle reaches the deceleration instruction value smaller when the absolute value of the deceleration instruction value is less than or equal to the upper limit value than when the absolute value of the deceleration instruction value is greater than the upper limit value The vehicle control device according to claim 1 or claim 2.

4. Comprising a condition determination unit that determines whether a predetermined reduction correction condition is satisfied, When at least one of the conditions that the occupant is looking at an image and that the occupant is reading is satisfied, the condition determination unit determines that the reduction correction condition is satisfied, When it is determined that the reduction correction condition is satisfied, the upper limit value setting unit sets a smaller value as the upper limit value than when it is not determined that the reduction correction condition is satisfied. The vehicle control device according to any one of claims 1 to 3.

5. When the vehicle is traveling on an expressway, the upper limit value setting unit sets a larger value as the upper limit value than when the vehicle is traveling on a road other than the expressway. The vehicle control device according to any one of claims 1 to 4.

6. The tilt angle acquisition unit acquires the head tilt angle based on the posture of the seat of the vehicle on which the occupant is seated. The vehicle control device according to any one of claims 1 to 5.

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