JP2023105637A - Control method and control device of vehicle seat - Google Patents

Abstract

To suppress a posture change of an occupant due to the lateral direction acceleration of a vehicle by changing the orientation of a seat back to the yaw direction of the vehicle, and suppress reduction in the comfort due to continuation of pressing against the seat back.SOLUTION: A control method of a vehicle seat comprises the steps of: detecting at least one of the lateral direction acceleration and steering angle of a vehicle (S1, S11); determining whether an absolute value of the lateral direction acceleration is increased or decreased on the basis of at least one of the lateral direction acceleration and steering angle (S3, S13); and turning a seat back Sb such that the component of the lateral direction acceleration in parallel to the front-rear direction of the seat back Sb becomes the component facing forward in a period in which the absolute value of the lateral direction acceleration of the vehicle 1 is increased, and/or turning the seat back Sb such that the component of the lateral direction acceleration in parallel to the front-rear direction of the seat back Sb becomes the component facing backward in a period in which the absolute value of the lateral direction acceleration is decreased (S6, S16).SELECTED DRAWING: Figure 9

Description

The present invention relates to a vehicle seat control method and control device.

In Patent Document 1 below, a seat back support portion is made to have a movable structure, and a part of the inertia acceleration in the vehicle width direction that occurs in the occupant when changing lanes is decomposed into component force components that press the occupant against the seat back support portion. A technology has been proposed that suppresses the occupant's swinging and reduces car sickness by suppressing the occupant's movement with respect to the seat using a force component.

JP 2017-71370 A

However, according to the technique disclosed in Patent Document 1, the occupant is always subject to the force of being pressed against the seat back while the vehicle width direction acceleration is occurring, so the occupant is likely to feel a sense of oppression, which may impair comfort. There is
It is an object of the present invention to change the direction of the seat back in the yaw direction of the vehicle, thereby suppressing changes in the posture of the occupant due to lateral acceleration of the vehicle, and suppressing deterioration in comfort caused by being continuously pressed against the seat back. and

According to one aspect of the present invention, there is provided a control method for a vehicle seat in which at least the seat back can pivot in the yaw direction of the vehicle. The control method detects at least one of lateral acceleration and steering angle of the vehicle, determines whether the absolute value of the lateral acceleration increases or decreases based on at least one of the lateral acceleration and steering angle, and controls the vehicle. During the period in which the absolute value of the lateral acceleration of the During the period when the value is decreasing, the seat back is turned so that the lateral acceleration component parallel to the longitudinal direction of the seat back becomes the backward component.

According to the present invention, by changing the direction of the seat back in the yaw direction of the vehicle, it is possible to suppress the change in the posture of the occupant due to the lateral acceleration of the vehicle, and to suppress the decrease in comfort caused by being continuously pressed against the seat back.

1 is a schematic configuration diagram of an example of a vehicle control device according to an embodiment; FIG. FIG. 4 is an explanatory diagram of each direction set for the vehicle; (a) is a graph of the time change of the lateral acceleration of the lateral transient motion and the positive acceleration added by acceleration, and (b) is a time change of the lateral acceleration of the lateral transient motion and the negative acceleration added by the deceleration. 4 is a graph, and (c) is an experimental result showing changes in the roll attitude angle of the occupant in the cases of (a) and (b). (a) is a graph of lateral acceleration over time for lateral transient motion, (b) is a graph of deceleration and acceleration over time added by braking and driving of the vehicle, and (c) is a graph of occupant roll. It is a graph of time change of an attitude angle. (a) is a graph of changes over time in lateral acceleration and lateral jerk (lateral jerk) of the vehicle body that occur when changing lanes, and (b) is a graph of an example setting of the direction of the seat back vertical acceleration component. . FIG. 4 is a schematic diagram illustrating the relationship between the motion of the vehicle and the inertial force acting on the occupant; (a) to (d) are schematic diagrams for explaining the inertia acceleration acting on the occupant due to the lateral acceleration of the vehicle and the seatback vertical acceleration component. (a) is a graph of changes over time in lateral acceleration and lateral jerk of the vehicle body that occur when changing lanes, (b) is a graph of an example setting of the direction of the seatback vertical acceleration component, and (c) is It is a graph of time change of a steering angle and a steering angular velocity, and (d) is a graph of the composite code|symbol D which synthesize|combined the code|symbol of a steering angle, and the code|symbol of a steering angular velocity. 1 is a flow chart of a first example of a vehicle seat control method according to an embodiment; 7 is a flow chart of a second example of the vehicle seat control method of the embodiment.

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described with reference to the drawings. Note that each drawing is schematic and may differ from the actual one. Further, the embodiments of the present invention shown below are examples of apparatuses and methods for embodying the technical idea of the present invention. are not specific to the following: Various modifications can be made to the technical idea of the present invention within the technical scope defined by the claims.

Note that the term "longitudinal acceleration" as used herein includes not only the rate of increase in vehicle speed in the forward direction of the vehicle, but also the rate of decrease in that speed (that is, deceleration). In particular, the sign of acceleration is positive when the vehicle speed increases, and the sign of acceleration is negative when the vehicle speed decreases.
"Lateral acceleration" refers to acceleration that occurs in one direction (one of the left and right directions with respect to the forward direction of the vehicle) in the vehicle width direction, and acceleration that occurs along the other direction (one of the left and right directions) ) is a concept that includes the acceleration that occurs along For convenience of explanation, the sign of the "lateral acceleration" is defined as positive when going to the left and negative when going to the right with respect to the advancing direction of the vehicle.
Similarly, the direction in which the vehicle turns to the left is defined as the positive direction of the steering angle, and the direction in which the vehicle turns to the right is defined as the negative direction of the steering angle.

(composition)
FIG. 1 is a schematic configuration diagram of an example of a vehicle control device according to an embodiment. The vehicle 1 includes a vehicle control device 10 that controls running of the vehicle 1 . Driving control by the vehicle control device 10 includes at least one of autonomous driving control for automatically driving the vehicle 1 without the involvement of the driver, driving, braking, and steering of the vehicle 1 based on the driving environment around the vehicle 1. driving assistance control that assists the driver in driving the vehicle 1 by controlling the Driving support control may be, for example, automatic steering, automatic braking, preceding vehicle follow-up control, constant speed control, lane keeping control, merging support control, and the like.

The vehicle control device 10 includes an object sensor 11, a vehicle sensor 12, a positioning device 13, a map database (map DB) 14, a communication device 15, a navigation device 16, an actuator 17, a controller 18, and a seat actuator. 19.
The object sensor 11 detects a plurality of different types of objects around the vehicle 1, such as laser radar, millimeter wave radar, camera, LIDAR (Light Detection and Ranging, Laser Imaging Detection and Ranging) mounted on the vehicle 1. A detection sensor is provided.

The vehicle sensor 12 is mounted on the vehicle 1 and detects various information (vehicle signals) obtained from the vehicle 1 . For example, the vehicle sensors 12 include a vehicle speed sensor that detects the vehicle speed of the vehicle 1, a wheel speed sensor that detects the rotational speed of the tires of the vehicle 1, a three-axis acceleration sensor that detects the acceleration and deceleration of the vehicle 1 in three axial directions, A yaw rate sensor that detects the yaw angular velocity (yaw rate) of the vehicle body and a roll rate sensor that detects the roll angular velocity of the vehicle body are included.
Further, for example, the vehicle sensor 12 includes an accelerator sensor for detecting the accelerator opening of the vehicle, a brake sensor for detecting the amount of brake operation by the driver, a steering angle sensor for detecting the steering angle of the steered wheels, and a steering angle sensor for detecting the steering angle of the steering wheel. A steering angle sensor is included to detect the angle θ _s and information on the steering wheel angular velocity ω _s can also be obtained from the vehicle sensor 12 .

The positioning device 13 has a global positioning system (GNSS) receiver, receives radio waves from a plurality of navigation satellites, and measures the current position of the vehicle 1 . A GNSS receiver may be, for example, a global positioning system (GPS) receiver or the like. The positioning device 13 may be, for example, an inertial navigation device.
The map database 14 stores road map data. For example, the map database 14 may store high-precision map data suitable as map information for automatic driving. The map database 14 may store map data for navigation.
The communication device 15 performs wireless communication with a communication device outside the vehicle 1 . The communication method of the communication device 15 may be, for example, wireless communication using a public mobile phone network, vehicle-to-vehicle communication, road-to-vehicle communication, or satellite communication.

The navigation device 16 recognizes the current position of the vehicle using the positioning device 13 and acquires map information for the current position from the map database 14 . The navigation device 16 sets the travel route to the destination input by the occupant, and provides route guidance to the occupant according to the travel route. The navigation device 16 also outputs information on the set travel route to the controller 18 . During autonomous driving control, the controller 18 automatically drives the vehicle 1 so as to travel along the travel route set by the navigation device 16 .

The actuator 17 is a device that operates according to a control signal from the controller 18 so that the vehicle 1 is in a desired state of motion. Actuator 17 mainly includes a drive system actuator that adjusts acceleration in the longitudinal direction of vehicle 1 and a steering system actuator that adjusts turning motion of vehicle 1 .
When the vehicle 1 is equipped with an engine as a traveling drive source, the drive system actuator adjusts the throttle valve that adjusts the amount of air supplied to the engine (throttle opening) and the braking force that is applied to the wheels of the vehicle 1. Friction brakes and the like may be included.

When the vehicle 1 is equipped with a motor as a drive source (hybrid vehicle or electric vehicle), the drive system actuator includes a power adjustment device (inverter, converter, etc.) that adjusts the power supplied to the motor. good. In this case, the deceleration function of the drive system actuator may be realized by regenerative operation (regenerative braking) instead of or in addition to the friction braking.
On the other hand, the steering system actuator may include an assist motor that controls steering torque in an electric power steering system, or a steering motor that controls steering torque in a steer-by-wire system.

The seat actuator 19 is an actuator that rotates the seat back of a vehicle seat provided in the passenger compartment of the vehicle 1 in the yaw direction of the vehicle 1 to change the longitudinal direction of the seat back. Here, the yaw direction of the vehicle 1 is the direction of rotation about the direction perpendicular to the front-rear direction and the lateral direction of the vehicle 1 (hereinafter sometimes referred to as the “vertical direction”). Further, the front-rear direction of the seat back is a direction perpendicular to the front surface of the seat back.
The seat actuator 19 may rotate (rotate) only the seat back with respect to the seat cushion of the vehicle seat, or may rotate the seat back and the seat cushion integrally (that is, rotate the vehicle seat). good).

The controller 18 is an electronic control unit (ECU) that controls travel of the vehicle 1 . Further, the controller 18 drives the seat actuator 19 to control the longitudinal orientation of the seat back of the vehicle seat. The controller 18 includes a processor 18a and peripheral components such as a storage device 18b. The processor 18a may be, for example, a CPU or MPU.

The storage device 18b may include a semiconductor storage device, a magnetic storage device, an optical storage device, or the like. The storage device 18b may include memories such as registers, cache memory, and ROM and RAM used as main storage devices.
The functions of the controller 18 described below are implemented by, for example, the processor 18a executing a computer program stored in the storage device 18b.
Note that the controller 18 may be formed of dedicated hardware for executing each information processing described below. For example, controller 18 may comprise functional logic circuitry implemented in a general purpose semiconductor integrated circuit. For example, the controller 18 may have a PLD such as an FPGA.

Next, a method of controlling the vehicle seat of the vehicle 1 by the vehicle control device 10 of the embodiment will be described. For convenience of explanation, directions and angles of the vehicle 1 used in this specification are defined as shown in FIG. Reference sign O indicates an occupant riding in the vehicle 1, and reference sign S indicates a vehicle seat on which the occupant O sits. The occupant O may be a driver or a fellow passenger. The vehicle seat S includes at least a seat back Sb and a seat cushion Sc.

The “vertical direction”, the “front-rear direction” and the “lateral direction” are expressed as the ζ-axis direction, the ξ-axis direction and the η-axis direction, respectively.
Further, the angle with the torso of the occupant O as the axis and the direction from the .zeta.-axis to the .eta.-axis on the .zeta.-.eta. The angle with the torso of the occupant O as an axis and the direction from the ζ-axis to the ξ-axis on the ζ-ξ plane as a positive angle is referred to as a "pitch attitude angle Ψ".

The vehicle control device 10 changes the orientation of the seat back Sb when the vehicle 1 performs a lateral transient motion (hereinafter sometimes referred to as a "lateral transient motion"), thereby reducing the lateral inertial acceleration acting on the occupant O. To improve the comfort of the occupant during boarding by reducing the body sway of the occupant O caused by
In this specification, the term "transient lateral motion" refers to motion in which lateral acceleration changes (that is, motion in which lateral jerk occurs).

In Patent Document 1, the inertia acceleration applied to the occupant O due to the movement of the vehicle 1 is resolved into component force components in the direction of pressing the occupant O against the seat back Sb in the longitudinal direction of the trunk of the occupant O. By tilting the seat back Sb, the body of the occupant O is pressed against the seat back Sb. As a result, the friction between the seat back Sb and the body of the occupant O increases, so that the change in the roll posture angle Φ of the body of the occupant O with respect to the seat back Sb can be reduced.

In general, in order to improve the comfort of the occupant O while riding, it is sufficient to reduce the physical sway of the occupant O with respect to the movement of the vehicle 1 . For example, car sickness is caused by a mismatch between the motion sensed by the occupant's body and head and the motion perception by the occupant's vision (sensory confusion theory: Motion Conflict Theory).
By pressing the body of the occupant O against the seatback Sb as in Patent Document 1, it is possible to suppress the change in posture of the occupant O during lateral movement of the vehicle 1, so that the effect of reducing car sickness can be expected.

On the other hand, since inertial acceleration is also generated in the longitudinal direction of the occupant's body, the occupant receives acceleration in the longitudinal direction as the vehicle laterally moves. As a result, the occupant's body is moved not only in the roll direction but also in the pitch direction. In particular, the head is easily moved by longitudinal acceleration. As a result, there is a possibility that the car sickness reduction effect by reducing the change in the roll attitude angle Φ of the occupant O may be offset by the car sickness inducing tendency due to the body and head movement in the pitch direction.

FIGS. 3(a) to 3(c) show the simulation results of the maximum amplitude of the roll attitude angle Φ of the occupant O when a slight longitudinal acceleration is applied to the vehicle performing lateral transient motion. Here, as shown in FIGS. 3( a ) and 3 ( b ), a sine-wave lateral acceleration with an amplitude of 1.5 [m/s ² ] is generated by a lateral transient motion such as a lane change, and the occupant ±0.25 [m/s ² ], which is the acceleration of the magnitude of the boundary between whether or not O can be recognized (hereinafter sometimes referred to as "threshold acceleration"), is added.

In general, the lower limit of acceleration that humans can perceive in the longitudinal direction of the body in a static environment at the laboratory level (hereinafter referred to as “standard sensory threshold”) is about 0.05 to about 0.1 [m /s ² ]. However, when the vehicle is exposed to external factors such as vibration under the driving environment, the threshold acceleration at which the occupant O can be recognized is approximately 0.2 to approximately 0.3 [m/s ² ] (approximately 0.02 to 0.03 G). Even if the longitudinal acceleration of this magnitude is added, it is difficult for the passenger O to perceive it as acceleration or deceleration.

On the other hand, there is a clear difference in the movement of the occupant O's body as shown in FIG. 3( ^c ). , the roll attitude angle Φ of the occupant O is significantly smaller when a positive longitudinal acceleration (0.25 [m/s ² ]) is applied. This effect is considered to be due to an increase or decrease in friction caused by a change in the pressing load of the occupant O against the seatback Sb.
From this result, it can be seen that there is an acceleration region in which the change in posture of the occupant O can be reduced by acceleration or deceleration in the longitudinal direction without inducing discomfort or motion sickness.

Therefore, the inventors of the present invention used an inverted pendulum type occupant model to determine the occupant O The change of the roll attitude angle Φ was simulated. 4(a) to 4(c) show that when the vehicle 1 performs a predetermined lateral transient motion (lane change), the roll direction posture change stiffness of the occupant O is caused by the threshold acceleration (±0.025 G) in the longitudinal direction. shows the simulation results of the maximum amplitude of the roll posture angle Φ of the occupant O when
In this lane change, after a certain period of time (in this case, after 4 seconds), the vehicle 1 moves to the adjacent lane (the amount of lateral movement is defined) and returns to straight running, so that the vehicle speed is the same between the initial speed and the end. The optimization calculation was performed after setting the driving intention in , and the optimum solution was calculated with and without adding the threshold acceleration.

In the case of a lane change, the lateral acceleration in each of the phase of turning the longitudinal direction of the vehicle to the adjacent lane (hereinafter referred to as "moving phase I") and the phase of returning the longitudinal direction of the vehicle (hereinafter referred to as "return phase II") Two transient motions occur in which the direction of is reversed. For each transient motion, when the vehicle 1 is decelerated in the section where the absolute value of acceleration increases and the vehicle 1 is accelerated in the section where the absolute value of acceleration decreases, the roll attitude angle Φ of the body of the occupant O changes. was found to be the smallest. According to this simulation result, the change in the roll attitude angle Φ of the occupant O could be reduced by about 17% compared to the case where the vehicle 1 is not subjected to longitudinal acceleration.

In the present invention, instead of applying the threshold acceleration in the longitudinal direction as described above, the seat back Sb is turned so that the inertia acceleration applied to the occupant O due to the lateral motion of the vehicle 1 is parallel to the longitudinal direction of the seat back Sb. Acceleration in the front-rear direction of the body trunk of the occupant O (that is, in the front-rear direction of the seat back Sb) is generated by vector decomposition into a component and a vertical component.
If the acceleration in the longitudinal direction of the seat back Sb is generated in the same manner as the acceleration in FIG. 4(b), the same effect as the simulation result in FIG. 4(c) can be obtained.
In the following description, the component parallel to the longitudinal direction of the seat back Sb generated from the inertia acceleration applied to the occupant O due to the lateral motion of the vehicle 1 by changing the direction of the seat back Sb is referred to as the "seat back vertical acceleration component". I have something to do.

A setting example of the seat back vertical acceleration component will be described with reference to FIGS. 5(a) and 5(b). FIG. 5(a) is a graph showing changes over time in the lateral acceleration and lateral jerk of the vehicle body that occur when the vehicle 1 changes lanes, and FIG. graph.
Whether the absolute value of the lateral acceleration is increasing or decreasing can be determined by the sign of the product of the lateral acceleration and the lateral jerk (first order differential of the lateral acceleration).
Therefore, for example, the controller 18 acquires the lateral acceleration detected by the triaxial acceleration sensor of the vehicle sensor 12 and differentiates the lateral acceleration to calculate the lateral jerk. Then, the direction of the seatback vertical acceleration component may be set based on the sign function Sgn [lateral acceleration×lateral jerk]. The sign function Sgn[x] is a function that becomes Sgn[x]=+1 when the variable x>0, Sgn[x]=0 when the variable x=0, and Sgn[x]=-1 when the variable x<0. is.
Specifically, when the value of the sign function Sgn [lateral acceleration x lateral jerk] is "1", the absolute value of the lateral acceleration increases, so the direction of the seatback vertical acceleration component is directed in the deceleration direction (that is, forward). Also, when the value of the sign function Sgn [lateral acceleration x lateral jerk] is "-1", the absolute value of the lateral acceleration decreases, so the direction of the seatback vertical acceleration component is set in the acceleration direction (that is, in the rearward direction). set to

In the examples of FIGS. 5A and 5B, the lane change of the vehicle 1 includes a first phase I-1 in which the signs of the lateral acceleration and the lateral jerk are both positive, and A second phase I-2 in which the sign is positive and the sign of the lateral jerk is negative, a third phase II-1 in which the signs of the lateral acceleration and the lateral jerk are both negative, and the sign of the lateral acceleration becomes negative and the sign of the lateral jerk is positive.
Therefore, the direction of the seat back vertical acceleration component is set in the deceleration direction in the first phase I-1 and the third phase II-1, and the direction of the seat back vertical acceleration component is set in the second phase I-2 and the fourth phase II-2. Set the orientation to the direction of acceleration.

FIG. 6 is a schematic diagram illustrating the relationship between the motion of the vehicle 1 and the inertial acceleration applied to the occupant O when changing lanes. Here, a case where the vehicle 1 changes lanes to the left lane will be described as an example. When changing lanes to the right lane, the explanation of the symbols is reversed.
In movement phase I, a positive turning force is applied to move the vehicle 1 from the current driving lane to the adjacent lane to be changed (the steering angle θ _s becomes positive). As a result, a leftward lateral acceleration Ay is generated in the vehicle 1, and a rightward inertial acceleration Ai acts on the occupant O.
The movement phase I further includes a first phase I-1 in which the steering angle θ _s increases from 0 to the maximum steering angle θ _smax , and a second phase I-2 in which the steering angle θ _s decreases from the maximum steering angle θ _smax to 0. divided into The absolute value of the lateral acceleration Ay increases in the first phase I-1 and decreases in the second phase I-2.

On the other hand, in the return phase II, a turning force in the negative direction is applied (the steering angle θs becomes negative) in order to restore the orientation of the vehicle 1 in the adjacent lane to which the vehicle is to be changed. As a result, a rightward lateral acceleration Ay is generated in the vehicle 1, and a leftward inertial acceleration Ai acts on the occupant O.
The return phase II further includes a third phase II-1 in which the steering angle θ _s decreases from 0 to the minimum steering angle θ _smin , and a fourth phase II-2 in which the steering angle θ _s increases from the minimum steering angle θ _smin to 0. divided into The absolute value of the lateral acceleration Ay increases in the third phase II-1, and decreases in the fourth phase II-2.

7(a) to 7(d) are setting examples of the direction of the seat back Sb in the first phase I-1, the second phase I-2, the third phase II-1, and the fourth phase II-2, respectively. indicates
By tilting the back surface of the seat back Sb in the longitudinal direction with respect to the longitudinal direction of the vehicle body, the inertia acceleration Ai in the lateral direction (vehicle width direction) acting on the occupant O becomes the seat back vertical acceleration component A1 (that is, the seat back Sb). component parallel to the front-rear direction) and a component A2 perpendicular to the front-rear direction of the seat back Sb.

In the first phase I-1 and the third phase II-1, as shown in FIGS. 7(a) and 7(c), the direction of the seatback vertical acceleration component A1 is set in the deceleration direction (that is, the forward direction). The seat back Sb is turned. For this reason, the controller 18 controls the direction of the seatback Sb so that the direction perpendicular to the front surface of the seatback Sb (that is, the direction of the seatback vertical acceleration component A1) is inclined in the forward direction of the vehicle body in the direction opposite to the steering direction. set.
For example, in the first phase I-1 (FIG. 7(a)), since the steering is leftward, the seat is tilted so that the direction perpendicular to the front surface of the seatback Sb is rightward with respect to the forward direction of the vehicle body. Set the direction of the back Sb. In the third phase II-1 (FIG. 7(c)), since the steering is to the right, the seatback Sb is tilted so that the direction perpendicular to the front surface of the seatback Sb is inclined leftward with respect to the forward direction of the vehicle body. set the orientation of the

In the second phase I-2 and the fourth phase II-2, as shown in FIGS. 7(b) and 7(d), the direction of the seatback vertical acceleration component A1 is set in the acceleration direction (that is, the rearward direction). The seat back Sb is turned. Therefore, the controller 18 sets the direction of the seat back Sb so that the direction perpendicular to the front surface of the seat back Sb is inclined in the steering direction with respect to the forward direction of the vehicle body.
For example, in the second phase I-2 (FIG. 7(b)), since the steering is leftward, the seat is arranged so that the direction perpendicular to the front surface of the seatback Sb is inclined leftward with respect to the forward direction of the vehicle body. Set the orientation of the back Sb. In the fourth phase II-2 (FIG. 7(d)), since the steering is to the right, the seatback Sb is tilted so that the direction perpendicular to the front surface of the seatback Sb is inclined to the right with respect to the forward direction of the vehicle body. set the orientation of the

The inclination angle α at which the direction perpendicular to the front surface of the seatback Sb is inclined with respect to the forward direction of the vehicle body is such that the seatback vertical acceleration component A1 generated by inclining the seatback Sb, for example, is a threshold acceleration (approximately 0.2 to approximately 0.3 [m/s ² ]) or less.
For example, the maximum value of the lateral inertial acceleration that occurs in a normal lane change operation is estimated to be 1.5 [m/s ² ], and the acceleration/deceleration of the engine brake, which is considered to cause less discomfort to the occupant O, is set to 0.25 [m /s ² ], the inclination angle α that generates the seatback vertical acceleration component A1 of 0.25 [m/s ² ] is approximately 9.6 [deg].

A second example of the method of setting the direction of the seat back vertical acceleration component will be described with reference to FIGS. 8(a) to 8(d). Here, the direction of the seat back vertical acceleration component is set based on the steering angle θ _s and the steering angular velocity ω _s of the steering wheel instead of the lateral acceleration and lateral jerk.
The steering angle θ _s and the steering angular velocity ω _s can be obtained using sensor signals that are almost standard in an electronically controlled steering system. On the other hand, the lateral jerk can be obtained by differentiating the lateral acceleration sensor signal, but the noise component increases in the calculation process and the accuracy tends to decrease.

In the vehicle transient motion in the linear region assumed in this specification (that is, the region in which the tire lateral force can be linearly proportionally approximated with respect to the tire slip angle), the shape of the waveform of the lateral acceleration and the waveform of the steering angle θ _s becomes almost equal, and the shape of the waveform of the lateral jerk and the shape of the waveform of the steering angular velocity _ωs become almost equal. Therefore, the steering angle θ _s and the steering angular velocity ω _s can be used instead of the lateral acceleration and lateral jerk.

FIG. 8(a) is a graph showing changes over time in the lateral acceleration and lateral jerk of the vehicle body that occur when the vehicle 1 changes lanes, and FIG. 8(c) is a graph of changes over time in the steering angle θ _s and the steering angular velocity ω _s , and FIG. graph.
As with the lateral acceleration and the lateral jerk, it can be determined whether the absolute value of the lateral acceleration is increasing or decreasing based on the sign of the steering angle _θs and the sign of the steering angular velocity _ωs .

For example, the controller 18 may acquire the steering angle θ _s detected by the steering angle sensor of the vehicle sensor 12 and differentiate the steering angle θ _s to calculate the steering angular velocity ω _s . Then, based on the composite code D=−Sgn[θ _s ×ω _s ], it may be determined whether the absolute value of the lateral acceleration is increasing or decreasing, and the direction of the seat back vertical acceleration component may be set. .
Specifically, when the value of the composite code D is "-1", it is determined that the absolute value of the lateral acceleration increases, and the direction of the seatback vertical acceleration component is set in the deceleration direction (ie forward direction). If the value of the composite code D is "1", it is determined that the absolute value of the lateral acceleration decreases, and the direction of the seatback vertical acceleration component is set in the acceleration direction (that is, in the rearward direction).

In the setting example of the seatback vertical acceleration component described above, after the seatback Sb is turned so that the seatback vertical acceleration component becomes a forward component, the seat is rotated so that the seatback vertical acceleration component becomes a rearward component. Although the back Sb is turned, it is not necessary to execute both turning in which the seat back vertical acceleration component is a forward component and turning in which the seat back vertical acceleration component is a rearward component.
That is, during a period when the absolute value of the lateral acceleration is increasing, the seat back Sb is turned so that the seat back vertical acceleration component becomes a forward component, or during a period when the absolute value of the lateral acceleration is decreasing. If the seat back Sb is turned so that the seat back vertical acceleration component becomes a backward component, the effect of reducing the change in the roll posture angle Φ of the occupant O can be expected.

(motion)
FIG. 9 is a flowchart of a first example of the vehicle seat control method of the embodiment.
In step S<b>1 , the triaxial acceleration sensor of vehicle sensor 12 detects lateral acceleration of vehicle 1 .
In step S2, the controller 18 calculates the lateral jerk by differentiating the lateral acceleration.
In step S3, the controller 18 calculates the sign function Sgn [lateral acceleration x lateral jerk] of the product of the lateral acceleration and the lateral jerk, and calculates the calculated sign function Sgn [lateral acceleration x lateral jerk]. direction jerk] is used to set the direction of the seat back vertical acceleration component. The controller 18 outputs a command signal (hereinafter sometimes referred to as a "seatback turning command signal") for turning the seatback Sb by a predetermined inclination angle α so as to generate a seatback vertical acceleration component in a set direction. Generate.

In step S4, the controller 18 performs high-pass filtering on the seatback turning command signal. The high-pass filtering corrects the seat back turn command signal to have value only during transient motion conditions, eliminating steady motion of the vehicle 1 .
In step S5, the controller 18 applies low-pass filter processing to the seat back turning command signal after high-pass filter processing. As a result, the turning speed of the seat back Sb by the seat actuator 19 is made equal to or less than the set value, thereby suppressing the influence of the turning motion of the seat back Sb on the occupant's kinesthetic perception.
In step S6, the controller 18 outputs the low-pass filtered seatback turning command signal to the seat actuator 19, and rotates the back surface of the seatback Sb so that the direction of the seatback vertical acceleration component becomes the direction set in step S3. The longitudinal direction is inclined with respect to the longitudinal direction of the vehicle body. Processing then ends.

FIG. 10 is a flowchart of a second example of the vehicle seat control method of the embodiment.
In step S11, the controller 18 and the steering angle sensor of the vehicle sensor 12 detect the steering angle _θs of the steering wheel.
In step S<b>12 , the controller 18 acquires the steering angular velocity signal of the steering angular velocity ω _s from the vehicle sensor 12 . The controller 18 may calculate the steering angular velocity ω _s by differentiating the steering angle θ _s .
In step S13, the controller 18 calculates a composite code D=−Sgn[θ _s ×ω _s ], and based on the composite code D, sets the direction of the seatback vertical acceleration component. The controller 18 generates a seatback pivot command signal to generate a seatback vertical acceleration component in the set direction.
The processing of steps S14 to S16 is the same as the processing of steps S4 to S6 described with reference to FIG.

(Modification)
The controller 18 may turn the seat back Sb as described above and apply a slight longitudinal acceleration to the vehicle 1 when the vehicle 1 performs lateral transient motion. As a result, the effect of reducing the change in the posture of the occupant O caused by turning the seat back Sb in the yaw direction of the vehicle 1 during lateral transient motion, and the posture of the occupant O caused by applying longitudinal acceleration to the vehicle 1. It is possible to synergistically exhibit the effect of reducing the change.

Specifically, the controller 18 sets the basic longitudinal acceleration Ab to be generated in the vehicle 1 according to the operation amount of the accelerator pedal by the driver or the required driving force set by the autonomous driving control or the driving support control. The basic longitudinal acceleration Ab corresponds to a target value of acceleration (a target value corresponding to the required driving force) for realizing the intended translational motion of the vehicle 1 according to the driving scene.

Next, the controller 18 calculates a front-rear acceleration (hereinafter referred to as "corrected front-rear acceleration Ac") added to suppress the change in posture of the occupant O. For example, the controller 18 may set the corrected longitudinal acceleration Ac based on the following equation (1) or (2).
Ac=−Sgn [lateral acceleration×lateral jerk]×|a| (1)
Ac=−Sgn[θ _s ×ω _s ]×|a| (1)
However, |a| is a predetermined set acceleration amount.

That is, the controller 18 decelerates the vehicle 1 when turning the seatback Sb so that the seatback vertical acceleration component (lateral acceleration component parallel to the longitudinal direction of the seatback Sb) becomes a forward component. The vehicle 1 is accelerated when the seatback Sb is turned so that the vertical acceleration component is a backward component.
It is preferable that the length of time during which the negative corrected longitudinal acceleration Ac is applied and the length of time during which the positive corrected longitudinal acceleration Ac is applied are set to substantially the same length. As a result, the average speed change is almost zero, and the intention of the vehicle motion is not disturbed.

The controller 18 calculates the target longitudinal acceleration At by adding the corrected longitudinal acceleration Ac to the basic longitudinal acceleration Ab. The controller 18 calculates the operation amount of the actuator 17 so that the actual longitudinal acceleration of the vehicle 1 approaches the target longitudinal acceleration At, and controls the actuator 17 based on the operation amount. More specifically, the controller 18 controls the throttle opening, motor output, or friction brake so as to satisfy the target longitudinal acceleration At.

In particular, when the vehicle 1 is an electric vehicle, the controller 18 operates the power regulator to apply positive torque to the motor when increasing the magnitude of the target longitudinal acceleration At (accelerating the vehicle 1). . On the other hand, when the magnitude of the target longitudinal acceleration At is to be decreased (the vehicle 1 is decelerated), the controller 18 either operates the power control device to apply negative torque to the motor or increases the braking force of the friction brake. , or perform both operations.

(Effect of Embodiment)
(1) The controller 18 controls the vehicle seat S in which at least the seat back Sb can turn in the yaw direction of the vehicle 1 . The vehicle sensor 12 detects at least one of the lateral acceleration and the steering angle of the vehicle 1 and determines whether the absolute value of the lateral acceleration increases or decreases based on at least one of the lateral acceleration and the steering angle. , during a period in which the absolute value of the lateral acceleration of the vehicle 1 is increasing, the seat back Sb is turned so that the component of the lateral acceleration parallel to the longitudinal direction of the seat back Sb becomes a forward component, and/or During the period in which the absolute value of the lateral acceleration is decreasing, the seatback Sb is turned so that the component of the lateral acceleration parallel to the longitudinal direction of the seatback Sb becomes the backward component.

As a result, the direction of the seat back Sb is controlled in correspondence with the sections in which the lateral acceleration due to the vehicle motion increases and decreases, respectively, so that the lateral inertial acceleration applied to the body of the occupant O is reduced by the seat back Sb. vector decomposition into a component parallel to the longitudinal direction (seat back vertical acceleration component) and a vertical component, and using the seat back vertical acceleration component, the transient of the occupant O seated on the vehicle seat S It is possible to suppress changes in body posture.

In particular, the direction of the inertial acceleration applied to the body of the occupant O in the longitudinal direction of the seat back Sb changes between the interval in which the lateral acceleration increases and the interval in which the lateral acceleration decreases. It is possible to suppress the decline in sexuality.
In addition, since the seat back vertical acceleration component becomes a forward component in the first half of the lateral transient motion in which the absolute value of the lateral acceleration increases, the body surface pressure of the occupant O on the seat back Sb can be reduced. As a result, the restraint on the movement of the body from the seat back Sb is reduced, and it is possible to reduce the movement of the occupant O forcibly following the body roll movement, and as a result, the change in the occupant's posture is suppressed. can.

Further, in the latter half of the lateral transient motion in which the absolute value of the lateral acceleration decreases, the seatback vertical acceleration component becomes a rearward component, so the body surface pressure of the occupant O on the seatback Sb can be increased. As a result, the restraint on the movement of the body from the seat back Sb is increased, and the movement of the body of the occupant O, who is moving with a delay with respect to the vehicle body roll motion, is made easier to follow the seat. Posture change can be suppressed.

(2) The controller 18 pivots the seatback Sb so that the component of the lateral acceleration parallel to the longitudinal direction of the seatback Sb becomes a forward component during the period when the absolute value of the lateral acceleration increases. Later, during the period when the absolute value of the lateral acceleration is decreasing, the seat back Sb may be turned so that the component of the lateral acceleration parallel to the longitudinal direction of the seat back Sb becomes the backward component.
As a result, the direction of the inertial acceleration applied to the body of the occupant O in the longitudinal direction of the seatback Sb changes between the interval in which the lateral acceleration increases and the interval in which the lateral acceleration decreases. A decrease in comfort can be suppressed.

(3) The controller 18 calculates the lateral jerk based on the lateral acceleration, and calculates the absolute value of the lateral acceleration when the sign of the product obtained by multiplying the lateral acceleration and the lateral jerk is positive. increases, and if the sign of the product is negative, it may be determined that the absolute value of the lateral acceleration decreases. Thereby, the direction of the seat back Sb for suppressing the posture change of the occupant O can be determined.

(4) The controller 18 detects the steering angle of the vehicle 1, calculates the steering angular velocity based on the steering angle, and calculates the lateral acceleration when the sign of the product obtained by multiplying the steering angle by the steering angular velocity is positive. increases, and if the sign of the product is negative, it may be determined that the absolute value of the lateral acceleration decreases. Thereby, the direction of the seat back Sb for suppressing the posture change of the occupant O can be determined.

(5) The controller 18 decelerates the vehicle 1 when turning the seatback Sb so that the lateral acceleration component parallel to the longitudinal direction of the seatback Sb becomes a forward component. The vehicle 1 may be accelerated when the seat back Sb is turned so that the component of the parallel lateral acceleration becomes the backward component.
As a result, the effect of reducing the change in the posture of the occupant O caused by turning the seat back Sb in the yaw direction of the vehicle 1 during the lateral transient motion, and the effect of reducing the change in the occupant O's posture caused by the addition of longitudinal acceleration to the vehicle 1. The effect of reducing the posture change can be synergistically exhibited.

DESCRIPTION OF SYMBOLS 1... Vehicle 10... Vehicle control apparatus 11... Object sensor 12... Vehicle sensor 13... Positioning apparatus 14... Map database 15... Communication apparatus 16... Navigation apparatus 17... Actuator 18... Controller 18a... Processor 18b Storage device 19 Seat actuator O Occupant S Vehicle seat Sb Seat back Sc Seat cushion

Claims (6)

A control method for a vehicle seat in which at least a seat back can turn in a yaw direction of the vehicle, comprising:
detecting at least one of a lateral acceleration or a steering angle of the vehicle;
determining whether the absolute value of the lateral acceleration increases or decreases based on the at least one of the lateral acceleration or the steering angle;
During a period in which the absolute value of the lateral acceleration of the vehicle increases, the seatback is turned so that the component of the lateral acceleration parallel to the longitudinal direction of the seatback is a forward component, and/or rotating the seat back so that a component of the lateral acceleration parallel to the longitudinal direction of the seat back becomes a backward component during a period in which the absolute value of the lateral acceleration is decreasing;
A control method characterized by: After turning the seat back so that the component of the lateral acceleration parallel to the longitudinal direction of the seat back becomes a forward component during the period in which the absolute value of the lateral acceleration is increasing, 2. The seat back is turned so that the component of the lateral acceleration parallel to the longitudinal direction of the seat back becomes a backward component during a period when the absolute value of the acceleration is decreasing. Described control method. calculating a lateral jerk based on the lateral acceleration;
When the sign of the product obtained by multiplying the lateral acceleration and the lateral jerk is positive, it is determined that the absolute value of the lateral acceleration increases, and when the sign of the product is negative, the lateral direction 3. The control method according to claim 1, wherein it is determined that the absolute value of acceleration decreases. calculating a steering angular velocity based on the steering angle;
When the sign of the product obtained by multiplying the steering angle and the steering angular velocity is positive, it is determined that the absolute value of the lateral acceleration increases, and when the sign of the product is negative, the absolute value of the lateral acceleration is determined. determine that the value is decreasing,
3. The control method according to claim 1 or 2, characterized in that: decelerating the vehicle when turning the seat back so that the component of the lateral acceleration parallel to the longitudinal direction of the seat back becomes a forward component;
accelerating the vehicle when turning the seat back so that the component of the lateral acceleration parallel to the longitudinal direction of the seat back becomes a backward component;
The control method according to any one of claims 1 to 4, characterized in that: A control device for a vehicle seat capable of turning at least a seat back in the yaw direction of the vehicle,
a sensor for detecting at least one of lateral acceleration and steering angle of the vehicle;
determining whether the absolute value of the lateral acceleration increases or decreases based on the at least one of the lateral acceleration and the steering angle, and during a period in which the absolute value of the lateral acceleration of the vehicle increases , rotating the seat back so that the component of the lateral acceleration parallel to the longitudinal direction of the seat back is a forward component; A control device, comprising: a controller for turning the seat back so that a component of the lateral acceleration parallel to the longitudinal direction of the seat back becomes a backward component.

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