Vehicle motion control method and vehicle motion control device

Abstract

The present invention provides a vehicle motion control method, which controls the motion state of a vehicle during a vehicle transition motion in which the vehicle generates lateral acceleration. In the vehicle motion control method, a modified fore-and-aft acceleration is set for correcting a basic fore-and-aft acceleration determined based on a requested driving force for vehicle travel, a target fore-and-aft acceleration is determined based on the basic fore-and-aft acceleration and the modified fore-and-aft acceleration, and a vehicle travel actuator is operated based on the target fore-and-aft acceleration, and the direction and magnitude of the modified fore-and-aft acceleration are determined from the viewpoint of suppressing posture changes in the roll direction of a vehicle occupant.

Description

Technical Field

[0001] The invention relates to a vehicle motion control method and a vehicle motion control device. Background Art

[0002] JP2017-71370A proposes a vehicle occupant posture control device, which predicts the acceleration in the vehicle width direction (lateral direction) based on the vehicle's driving plan in an autonomous vehicle, changes the support state of the vehicle seat for the occupant, and stabilizes the occupant's posture. In particular, in the vehicle occupant posture control device, before the acceleration (lateral acceleration) accompanying vehicle steering occurs, such as when changing lanes, the movable part (seat back support part and armrest, etc.) of the vehicle seat is operated in response to the acceleration to support the occupant's body.

[0003] However, in JP2017-71370A, it is necessary to adopt a mechanical structure for realizing the mobility of the vehicle seat, which may cause a concern about the complication of the vehicle structure and an increase in manufacturing costs. Summary of the invention

[0004] In view of the above circumstances, an object of the present invention is to provide a vehicle motion control method and a vehicle motion control device, which can suppress the change of the posture of the occupant with a simpler structure during the transient motion of the vehicle generating lateral acceleration.

[0005] According to one embodiment of the present invention, a vehicle motion control method is provided for controlling the motion state of a vehicle in a vehicle transient motion in which the vehicle generates lateral acceleration. In the vehicle motion control method, a modified fore-and-aft acceleration is set for modifying a basic fore-and-aft acceleration determined based on a requested driving force for vehicle travel, a target fore-and-aft acceleration is determined based on the basic fore-and-aft acceleration and the modified fore-and-aft acceleration, and a travel actuator of the vehicle is operated based on the target fore-and-aft acceleration, wherein the direction and magnitude of the modified fore-and-aft acceleration are determined from the viewpoint of suppressing a posture change of a vehicle occupant in a roll direction. BRIEF DESCRIPTION OF THE DRAWINGS

[0006] Figure 1 It is a diagram for explaining the structure of a vehicle motion control device that executes the vehicle motion control method according to each embodiment of the present invention.

[0007] Figure 2 It is a diagram for explaining each direction set in the vehicle.

[0008] Figure 3 is a flow chart illustrating a method of controlling vehicle motion.

[0009] Figure 4 This is a diagram for explaining the relationship between the movement of a vehicle and the inertial force acting on the occupant.

[0010] Figure 5A This is a diagram for explaining the corrected longitudinal acceleration set in the first embodiment.

[0011] Figure 5B This is a diagram for explaining the effect of the corrected longitudinal acceleration set in the first embodiment.

[0012] Figure 6 It is a diagram for explaining the setting of the corrected longitudinal acceleration in the second embodiment.

[0013] Figure 7 It is a diagram for explaining the control result of the vehicle motion control method according to the second embodiment.

[0014] Figure 8 It is a figure which shows the simulation result of each Example and comparative example. DETAILED DESCRIPTION

[0015] Hereinafter, various embodiments of the present invention will be described with reference to the accompanying drawings, etc. In addition, the concept of "lane change" in this specification includes not only the usual lane change of moving from the current lane to the adjacent lane in order to turn left or right at an intersection to reach a predetermined destination, or moving to a lane close to an exit of a highway, but also the so-called merging such as moving from the lane at the entrance of a highway to the main line.

[0016] In addition, "autonomous driving" in this specification is a concept that includes both vehicle motion control that assists a part of the vehicle driver's driving operation (autonomous driving levels 1 to 4) and vehicle motion control without driver operation (autonomous driving level 5).

[0017] Furthermore, the "front-rear acceleration" in this specification is a concept that includes not only the rate of increase (normal acceleration) of the speed (vehicle speed) in the vehicle's forward direction, but also the rate of decrease (i.e., deceleration) of the speed. In particular, the sign of the acceleration when the vehicle speed increases is set to positive, and the sign of the acceleration when the vehicle speed decreases is set to negative. In addition, similarly, the "lateral acceleration" is a concept that includes not only the acceleration generated in one direction along the vehicle width direction (left or right relative to the vehicle's forward direction), but also the acceleration generated in another direction (right or left relative to the vehicle's forward direction). In particular, in each embodiment described below, for the sake of convenience, the sign of the "lateral acceleration" is defined as positive when it is toward the left relative to the vehicle's forward direction, and negative when it is toward the right.

[0018] [Common Structure in Each Embodiment]

[0019] Figure 1The vehicle motion control system 10 is a block diagram for explaining the structure of a vehicle motion control system 10 for executing the vehicle motion control method of each embodiment. The vehicle motion control system 10 is mounted on a vehicle (hereinafter referred to as "vehicle α") that is to execute the vehicle motion control method of the present embodiment.

[0020] As shown in the figure, the vehicle motion control system 10 includes sensors 12 , a travel actuator 14 , and a controller 16 as a vehicle motion control device.

[0021] The sensors 12 are composed of various detectors (vehicle cameras, radars, laser radars, etc.) that detect the surrounding conditions of the vehicle α, and various detection devices (accelerator pedal sensor, vehicle speed sensor, acceleration sensor, steering angle sensor, yaw rate sensor, etc.) that detect the internal information corresponding to the driving state of the vehicle α. The sensors 12 output the detected surrounding information to the controller 16. In particular, in the present embodiment, the steering angle sensor as a part of the sensors 12 detects the steering angle θ of the vehicle α. s , and output to the controller 16.

[0022] In addition, from the viewpoint of allowing the controller 16 to acquire other necessary external information (GPS information, etc.), the vehicle motion control system 10 may include a communication unit for accessing a system outside the vehicle α.

[0023] The travel actuator 14 is a device that operates to bring the vehicle α into a desired motion state based on a command from the controller 16. The travel actuator 14 mainly includes a drive system actuator that adjusts the acceleration of the vehicle α in the longitudinal direction and a steering system actuator that performs a turning operation of the vehicle α.

[0024] For example, when vehicle α is equipped with an engine as a driving source, the drive system actuator is composed of a throttle valve that adjusts the air supply to the engine (throttle opening), and a friction brake that adjusts the braking force applied to the wheels of vehicle α.

[0025] In addition, when the vehicle α is equipped with an electric motor as a driving source for traveling (in the case of a hybrid vehicle or an electric vehicle), the drive system actuator is composed of a power regulating device (an inverter and a converter, etc.) that regulates the power supplied to the electric motor. In this case, the deceleration function in the drive system actuator can also be realized by operating the regenerative operation (regenerative braking) of the electric motor by operating the power regulating device instead of or together with the friction brake.

[0026] On the other hand, the steering system actuator is composed of an assist motor that controls the steering torque in the electric power steering system.

[0027] The controller 16 is composed of a computer including a central processing unit (CPU), a read-only memory (ROM), a random access memory (RAM), and an input / output interface (I / O interface). The controller 16 is programmed to execute each process in the vehicle motion control method described below.

[0028] In particular, the controller 16 includes a setting unit 16 a and an operating unit 16 b which are realized by the above-mentioned various hardware configurations and programs.

[0029] The setting unit 16a stores a pre-set corrected longitudinal acceleration A described later. fr_c The storage area of ​​​​the steering angle θ from the sensor 12 s and other necessary information as input, and generates a command signal to be output to the operation unit 16b by referring to the storage area. In particular, the storage area of ​​the setting unit 16a stores the corrected front-to-back acceleration A set in the transitional motion (especially lane change) in which the lateral acceleration acts on the vehicle α by the turning action based on the steering operation. fr_c .

[0030] More specifically, the setting unit 16a calculates the basic longitudinal acceleration A according to the amount of operation of the accelerator pedal during the lane change or the requested driving force based on the instruction from the Advanced Driver Assistance Systems (ADAS). fr_tb Here, the basic front-to-back acceleration A fr_tb The target value of the acceleration for achieving the intended translational motion of the vehicle α according to the driving scene (the target value corresponding to the required driving force) is equivalent to the target value of the acceleration for achieving the intended translational motion of the vehicle α according to the driving scene. s The corrected front and rear acceleration A is calculated as input fr_c Here, the corrected front and rear acceleration A fr_c is a correction value of the acceleration determined from the viewpoint of suppressing the change in the posture of the occupant O during the travel of the vehicle α. fr_c The details of the setting of will be described later. fr_tb Add the corrected front and rear acceleration A fr_tc To calculate the final target front and rear acceleration A fr_t , and outputs it to the operating unit 16b.

[0031] The operating unit 16b makes the actual longitudinal acceleration of the vehicle α approach the final target longitudinal acceleration A. fr_t The operation amount of the travel actuator 14 is calculated in a manner as shown in FIG. 1 , and the travel actuator 14 is operated based on the operation amount. More specifically, the operation unit 16 b satisfies the final target longitudinal acceleration A. fr_tIn particular, when the vehicle α is an electric vehicle, the final target front and rear acceleration A is set to fr_t When the magnitude of is increased (when the vehicle α is accelerated), the operation unit 16b operates the power adjustment device in a manner that applies positive torque to the motor. On the other hand, when the final target longitudinal acceleration A is increased, fr_t When the size of is reduced (when the vehicle α is decelerated), the operating unit 16b operates the power adjustment device in a manner that applies negative torque to the electric motor, or increases the braking force based on the friction brake, or performs both operations.

[0032] In addition, the functions of the controller 16 can be realized by any computer mounted on the vehicle α, such as an ADAS (Advanced Driver Assistance Systems) controller, a motor controller, an ECU (Engine Control Unit), or a vehicle controller. In addition, the controller 16 can be configured as a single device, or can be configured to be divided into a plurality of devices and each process can be distributed by the plurality of devices.

[0033] Below, based on the above structure, the vehicle motion control method of each embodiment is described in detail. In addition, for reference, in the vehicle α used in this specification, Figure 2 The directions and angles are determined in this way. More specifically, the "vertical direction" corresponds to the z-axis direction, the "front-rear direction" corresponds to the ξ-axis direction, and the "lateral direction" corresponds to the η-axis direction. Furthermore, with the torso of the occupant O as the axis, the angle in the z-η plane with the direction from the z-axis toward the η-axis as the positive angle is called the "roll attitude angle φ". ro In addition, with the trunk of the occupant O as the axis, the angle in the ζ-ξ plane from the ζ axis to the ξ axis is called the “pitch attitude angle φ”. pi ”.

[0034] [First embodiment]

[0035] Hereinafter, a vehicle motion control method according to a first embodiment will be described.

[0036] Figure 3 Controller 16 repeatedly executes the processing described below at each predetermined control cycle.

[0037] First, in step S110, the controller 16 detects a lane change request for the vehicle α. Specifically, the controller 16 processes the detection of the operation of the direction indicator by the occupant O (especially the driver) or the reception of the lane change instruction from the ADAS controller that performs the automatic driving control as the detection of the lane change request. In addition, when the controller 16 is composed of an ADAS controller, it can also be configured to process the start time of the lane change determined by the controller 16 itself as the detection of the lane change request.

[0038] In step S120, the controller 16 obtains the steering angle θ from the sensor 12. s In addition, in this embodiment, the steering angle θ s Used as an indicator of the degree of progress of lane changes.

[0039] Figure 4 is the steering angle θ s In addition, for the sake of convenience, the direction in which the vehicle α turns left is defined as the steering angle θ. s positive direction.

[0040] As shown in the figure, the lane change is divided into the first half of the moving phase I and the second half of the returning phase II according to the state of the transitional motion of the vehicle α. Moreover, the moving phase I and the returning phase II are further divided into the steering angle θ s Two transitional movements in which the absolute value increases or decreases.

[0041] More specifically, in the movement phase I, a positive turning force (steering angle θ) is applied to move the vehicle α from the current driving lane to the adjacent lane of the lane change target. s is positive). That is, the moving stage I is the lateral acceleration A to the left in the figure. la The transitional motion interval acting on the vehicle α. Furthermore, the movement phase I is divided into the steering angle θ s From 0 to the maximum steering angle θ smax The first movement phase I-1, and the maximum steering angle θ smax The second movement phase I-2 decreases to 0 again. That is, the first movement phase I-1 is the lateral acceleration A la The absolute value of the steering angle θ s In addition, the second movement stage I-2 is the transition movement interval in which the lateral acceleration A la The absolute value of the steering angle θ s The absolute value of () is reduced in the transitional motion interval.

[0042] On the other hand, in the return phase II, a negative turning force (steering angle θ) is applied to return the direction of the vehicle α to the adjacent lane of the change target.s That is, the return phase II is the lateral acceleration A to the right in the figure in the opposite direction to the movement phase I. la The transitional motion interval acting on the vehicle α. Furthermore, the return phase II is divided into a first return phase II-1 and a second return phase II-2. In the first return phase II-1, the second movement phase I-2 is completed and the steering angle θ s Decrease from 0 to the minimum steering angle θ smin (θ s <0), in the second return phase II-2, the steering angle θ s From the minimum steering angle θ smin Increases to 0 again. That is, the first return phase II-1 is the lateral acceleration A la The absolute value of the steering angle θ s In addition, the second return phase II-2 is the transition motion interval in which the lateral acceleration A la The absolute value of the steering angle θ s The absolute value of () is reduced in the transitional motion interval.

[0043] Therefore, in each stage of the lane change, the lateral acceleration A acting on the vehicle α is la direction (steering angle θ s ) changes in different modes, so by referring to the steering angle θ s The progress of the current lane change can be understood.

[0044] Back to Figure 3 In step S130, the controller 16 calculates the corrected front and rear acceleration A fr_tc Specifically, the controller 16 determines the steering angle θ obtained in step S120 based on the steering angle θ. s , referring to the corrected front and rear acceleration A stored in the storage area fr_tc , calculate the corrected front and rear acceleration A corresponding to the current motion state of vehicle α fr_tc .

[0045] Then, in step S140, the controller 16 calculates the basic longitudinal acceleration A fr_tb And the calculated corrected front and rear acceleration A fr_tc Add them together to find the final target front and rear acceleration A fr_t , and operates the travel actuator 14 so that the actual longitudinal acceleration of the vehicle α approaches the final target longitudinal acceleration A fr_t .

[0046] Next, with regard to the vehicle motion control method according to the present embodiment, a background problem and a mechanism for solving the problem will be described.

[0047] Reference Figure 4It can be seen that in the lane change, by generating lateral acceleration A in different directions in the moving phase I and the returning phase II, la As a result, an inertial force in the roll direction (hereinafter also referred to as “roll direction inertial force F i_ro ”). Therefore, during the lane change, the posture of the occupant O is likely to change. Such a change in the posture of the occupant O becomes a major cause of motion sickness.

[0048] To explain in more detail, there is a theory that the cause of motion sickness is the mismatch between the motion sensed by the motion sensor and the motion recognition based on vision, etc., due to the movement of the body and head of the occupant O (Motion Conflict Theory). In particular, according to the Motion Conflict Theory, since the mismatch accumulates over time, motion sickness symptoms are likely to occur when it exceeds a certain level.

[0049] When it is applied to the above lane change scenario, when the inertial force F in the roll direction acts on the occupant O, i_ro , the head of the occupant O swings in the roll direction relative to the torso. As a result, the occupant O will continue to feel the mismatch between the motion sensed by the motion sensor (the swing of the head in the roll direction) and the motion recognition based on vision (the movement of the scenery outside the vehicle α observed by the occupant O), which is likely to induce motion sickness.

[0050] In view of this, in the present embodiment, the modified longitudinal acceleration A is set from the viewpoint of suppressing the change in the posture of the occupant O in the roll direction in the lane change scenario. fr_tc .

[0051] Figure 5A This is to explain the corrected front-rear acceleration A set in this embodiment. fr_tc As shown in the figure, in this embodiment, the front and rear acceleration A is corrected. fr_tc The direction of is set to the positive direction along the forward direction of the vehicle α in all stages of the lane change. fr_c The value of (hereinafter also referred to as "set acceleration value |a|") is set as the threshold value a of the feeling during the vehicle change in all stages. th A certain value of the degree of tiny size.

[0052] In addition, the threshold value of feeling when riding a vehicle in this specification is a th It refers to the lower limit of the acceleration magnitude that the passenger O riding on the vehicle α can recognize in the translation direction (especially the front-to-back direction) that the vehicle α is accelerating or decelerating. Therefore, if the set acceleration value |a| is set to the threshold a when riding thdegree, the occupant O cannot recognize the difference with respect to the basic front and rear acceleration A fr_tb Corrected acceleration A fr_tc Considerable acceleration changes.

[0053] It is known that in a static environment at the laboratory level (an environment without external forces such as vibration), the lower limit of the acceleration that a person can perceive in the front-to-back direction of the body (hereinafter also referred to as the "standard perception threshold") is about 0.05 to about 0.1 [m / s 2 ] This fact is recorded, for example, in "Predicting direction detection thresholds for arbitrary translational acceleration profiles in the horizontal plane" (Florian Soyka, Paolo Robuffo Giordano, Karl Beykirch, Heinrich H. Bulthoff, 2010, Experimental Brain Research) and the like.

[0054] Based on this, the inventors have made intensive studies and found that the lower limit of the magnitude of acceleration that the occupant O can perceive (hereinafter also referred to as the "sensation threshold value a during riding") is 1. th ”) is greater than the standard sensory threshold. More specifically, the inventors have found through experiments that the sensory threshold a when riding a vehicle is th The sensory threshold a is increased to several times or more (especially about 2 to 3 times) the standard sensory threshold. th Set to approximately 0.2 to 0.3 [m / s 2 ] range.

[0055] In particular, the roll attitude angle φ is increased as much as possible within a range where the occupant O does not perceive acceleration or deceleration. ro From the perspective of the suppression effect of the change of the occupant O's posture, the sensory threshold a during riding th It is preferred to select a range above a certain value (for example, 0.25 [m / s 2 ] or above).

[0056] Figure 5B This is to explain the setting of the corrected front-rear acceleration A of this embodiment. fr_c In particular, Figure 5B Indicates that the horizontal axis is set to the corrected front and rear acceleration A fr_c, the vertical axis is set to the roll attitude angle φ which is an index of the attitude change of the occupant O ro Graph of the maximum amplitude.

[0057] from Figure 5B It can be seen that if the acceleration before and after correction A fr_c The direction of is set to the positive direction (to accelerate the vehicle α), then the acceleration A is not set to correct the front and rear acceleration. fr_c or when the direction is set to the negative direction (A fr_c ≤0), the roll attitude angle φ ro This is because, by applying acceleration in the forward direction, an inertial force acts on the occupant O in the direction of pressing the seat surface of the seat S, and the friction between the torso of the occupant O and the seat surface of the seat S increases, making it difficult for the occupant O to change his posture. fr_c The direction is set to the positive direction, which can reduce the roll attitude angle φ ro changes.

[0058] On the other hand, according to the above theory, it can be basically considered that the acceleration A before and after correction fr_c The larger the value is in the positive direction, the greater the roll attitude angle φ ro However, the inventors also focus on the following aspects: if a certain magnitude or more of the corrected front and rear acceleration A is given, fr_c (especially when it greatly exceeds the above-mentioned sensory threshold a th The magnitude of the correction before and after acceleration A fr_c ), the occupant O recognizes it as the actual acceleration and deceleration of the vehicle α, and may feel uncomfortable, and may be dissatisfied with the motion state corresponding to the original driving purpose of the vehicle α (based on the basic front and rear acceleration A fr_tb speed).

[0059] Therefore, from the viewpoint of more reliably avoiding such discomfort to the occupant O and the influence on the motion state corresponding to the driving purpose of the vehicle α, in this embodiment, the set acceleration value |a| is set to the above-mentioned riding sensation threshold value a th Thus, while achieving the function of suppressing the posture change of the occupant O, the occupant O will not change the corrected longitudinal acceleration A fr_c By recognizing the actual acceleration and deceleration of the vehicle α, it is possible to suppress the discomfort caused and further reduce the influence on the motion state corresponding to the driving purpose of the vehicle α.

[0060] In addition, in the above lane change, since the basic longitudinal acceleration A is set for the vehicle α according to the original driving purpose, fr_tb, so the inertial force in the vehicle longitudinal direction (pitch direction) corresponding to it acts on the occupant O. In particular, when the basic longitudinal acceleration A fr_tb When the angle is large, the head of the occupant O swings accordingly (pitch attitude angle φ pi In contrast, according to the vehicle motion control method of this embodiment, the modified longitudinal acceleration A is set to the positive direction. fr_c The occupant O is pressed toward the seat S by the action of the roll attitude angle φ ro The change of can also suppress the pitch attitude angle φ pi That is, the posture change of the occupant O in both the roll direction and the pitch direction can be reduced.

[0061] According to the present embodiment having the above-described structure, the following effects can be achieved.

[0062] In this embodiment, a vehicle motion control method is provided, in which a lateral acceleration (lateral acceleration A) is generated in the vehicle α. la ) in the vehicle transition motion (lane change) (step S110) to control the motion state of the vehicle α. In the vehicle motion control method, a basic front-rear acceleration A determined according to the requested driving force for the vehicle α to travel is set. fr_tb The acceleration before and after correction A fr_c (Step S130), and according to the basic front and rear acceleration A fr_tb and the corrected front and rear acceleration A fr_tc To determine the target front and rear acceleration (the final target front and rear acceleration A fr_t ), based on the final target front and rear acceleration A fr_t The travel actuator 14 of the vehicle α is operated (step S140). Then, the rolling posture change (roll posture angle φ) of the occupant O of the vehicle α is suppressed. ro ) to determine the acceleration A before and after correction fr_c direction and size.

[0063] Therefore, in the lateral acceleration A la In the vehicle transition motion acting on vehicle α, the basic front-rear acceleration A corresponding to the original motion purpose is fr_tb The simple method of adjusting the direction and magnitude of the acceleration in the longitudinal direction of the vehicle α can suppress the posture change in the roll direction of the occupant O. In other words, the posture of the occupant O can be stabilized during the transient motion of the vehicle without using a complicated mechanical structure for making the seat S movable.

[0064] In this embodiment, the corrected longitudinal acceleration A fr_tcThe direction of is set to the positive direction along the forward direction of the vehicle α (ie, the acceleration direction).

[0065] As a result, an inertial force can act on the occupant O so as to increase the frictional force between the trunk of the occupant O and the seat surface of the seat S, and thus the effect of suppressing the change in the posture of the occupant O can be further enhanced.

[0066] In particular, in this embodiment, the corrected longitudinal acceleration A fr_tc The value of is set to the sensory threshold a of the vehicle after the sensory threshold (standard sensory threshold) for the translational acceleration of the person is corrected based on the driving environment of the vehicle α. th Or a value close to it.

[0067] Thus, during the transient motion of the vehicle, the front and rear acceleration A can be corrected within a range where the occupant O does not feel the acceleration or deceleration. fr_tc The magnitude (set acceleration value |a|) is set relative to the basic front and rear acceleration A fr_tb Therefore, it is possible to suppress the change in the posture of the occupant O in the roll direction while suppressing the occupant O from recognizing acceleration and deceleration. On this basis, the corrected longitudinal acceleration A can be set in a manner that does not deviate significantly from the original driving purpose of the vehicle α. fr_tc .

[0068] Furthermore, according to the present embodiment, a controller 16 is provided as a vehicle motion control device for executing the above vehicle motion control method. The controller 16 generates a lateral acceleration (lateral acceleration A la ) during the vehicle transition motion, control the motion state of vehicle α.

[0069] The controller 16 includes a setting unit 16a for setting a basic longitudinal acceleration A determined based on a required driving force for driving the vehicle α. fr_tb The acceleration before and after correction A fr_c ; Operating unit 16b, which is based on the basic front and rear acceleration A fr_tb And the acceleration before and after correction A fr_tc To determine the target front and rear acceleration (the final target front and rear acceleration A fr_t ), and based on the final target front and rear acceleration A fr_t To operate the travel actuator 14 of the vehicle α.

[0070] Thereby, a preferred control structure for executing the above-mentioned vehicle motion control method is realized.

[0071] [Second embodiment]

[0072] The second embodiment is described below. In addition, the same reference numerals are used for the same elements as those in the first embodiment, and their descriptions are omitted. Figure 3 The process in step S130 (correction of the longitudinal acceleration A fr_c ) are different.

[0073] Figure 6 This is to explain the modified longitudinal acceleration A in this embodiment. fr_c In addition, the processing of this flowchart is continued in Figure 3 The steering angle θ in step S120 described above s Start with the acquisition of .

[0074] First, in step S131, the controller 16 calculates the steering angular velocity ω s Specifically, the controller 16 controls the steering angle θ s Calculate the steering angular velocity ω by time differentiation s Alternatively, the controller 16 may receive the steering angular velocity ω calculated by the sensor 12 (particularly, a steering angle sensor that is standardly installed in an electronically controlled steering system). s structure.

[0075] In particular, in this embodiment, the steering angular velocity ω s Can be related to the steering angle θ s More specifically, the steering angular velocity ω during lane change is used as an indicator of the degree of progress of the lane change. s can be considered as the lateral acceleration A la The time rate of change (hereinafter also referred to as "lateral impact jump J la Therefore, by referring to the steering angle θ s and steering angular velocity ω s In addition to determining whether the current lane change of vehicle α is in the moving stage I or the returning stage II (steering angle θ s In addition to being positive or negative), it is also possible to detect in more detail whether it is the first movement phase I-1 or the second movement phase I-2 (steering angular velocity ω s is positive or negative), and determines whether it is the first return phase II-1 or the second return phase II-2 (steering angular velocity ω s is positive or negative).

[0076] Next, in step S132, the controller 16 calculates an acceleration / deceleration determination value D. Here, the acceleration / deceleration determination value D is an indicator of the degree of progress of the current lane change, that is, the steering angle θ. s and steering angular velocity ω sTo determine the corrected front and rear acceleration A in the appropriate direction fr_c Specifically, the controller 16 calculates the acceleration / deceleration determination value D based on the following equation (1).

[0077] D=-sgn(θ s ×ω s ) (1)

[0078] Here, "sgn()" is a sign function defined by the following equation (2).

[0079]

[0080] In step S133, the controller 16 calculates the provisional acceleration A pr , as the corrected acceleration A before filtering fr_c Specifically, the controller 16 obtains the provisional acceleration A by multiplying the acceleration / deceleration determination value D calculated in step S132 by the set acceleration value |a| described in the first embodiment. pr .

[0081] In step S134, the controller 16 calculates the provisional acceleration A pre The high-pass filter process is performed. The high-pass filter process is performed in the stable motion state of the vehicle α during the lane change, so as to correct the longitudinal acceleration A fr_c Here, the stable motion state in this embodiment refers to a state in which the actual acceleration in the longitudinal direction or lateral direction of the vehicle α is so small that it can be judged that there is substantially no change in the posture of the occupant O. That is, by executing this high-pass filtering process, in such a stable motion state, the correction of the longitudinal acceleration A is not applied. fr_c , and realize the acceleration and deceleration state corresponding to the original driving force requirement of vehicle α.

[0082] In step S135, the controller 16 processes the provisional acceleration A after high-pass filtering. pre Further, a low-pass filter process is performed. In addition, the low-pass filter process is to make the change of the acceleration / deceleration signal (steering angular velocity ω s The purpose of this low-pass filtering is to make the steering angular velocity ω s (equivalent to acceleration shock jump) When it changes in a short period of time due to some reasons, the acceleration A before and after correction is suppressed. fr_c The direction of the vehicle is switched in a short time, which affects the motion feeling of the occupant O.

[0083] Then, the controller 16 uses the corrected longitudinal acceleration A set as described above. fr_cThe process moves to the above-mentioned step S140.

[0084] The modified longitudinal acceleration A set by the vehicle motion control method of the present embodiment described above is fr_c method to explain.

[0085] Figure 7 is the modified longitudinal acceleration A set by the vehicle motion control method of this embodiment. fr_c In particular, Figure 7 (a)~ Figure 7 (d) represents the lateral acceleration A corresponding to the lane change. la and transverse impact jump J la , Corrected front and rear acceleration A fr_c , steering angle θ s and steering angular velocity ω s , and acceleration / deceleration determination value D.

[0086] As shown in the figure, according to the vehicle motion control method of this embodiment, at the steering angle θ s (lateral acceleration A la ) is positive in the moving phase I, at the steering angular velocity ω s (Transverse impact jump J la ) is positive in the first moving stage I-1, the acceleration / deceleration judgment value D is -1, and the front and rear acceleration A is corrected. fr_c is set to negative (deceleration direction). On the other hand, at the steering angular velocity ω s (Transverse impact jump J la ) is negative in the second moving stage I-2, the acceleration / deceleration judgment value D is 1, and the front and rear acceleration A is corrected. fr_c is set to positive (acceleration direction).

[0087] In addition, at the steering angle θ s (lateral acceleration A la ) is negative in the return phase II, at the steering angular velocity ω s (Transverse impact jump J la ) is positive in the first return phase II-1, the acceleration / deceleration judgment value D is -1, and the front and rear acceleration A is corrected. fr_c is set to negative (deceleration direction). On the other hand, at the steering angular velocity ω s (Transverse impact jump J la ) is negative in the second return phase II-2, the acceleration / deceleration judgment value D is 1, and the front and rear acceleration A is corrected. fr_c is set to positive (acceleration direction).

[0088] That is, in the present embodiment, during the lane change, at the steering angle θ sThe absolute value of the increase (θ s and s In the first moving phase I-1 and the first returning phase II-1 (with the same signs), the corrected front-rear acceleration A fr_c The direction of is set as the deceleration direction. s The absolute value of the decrease (θ s and s In the second moving phase I-2 and the second returning phase II-2 (with different signs), the front-rear acceleration A is corrected. fr_c The direction is set as the acceleration direction.

[0089] This can generate a roll attitude angle φ that can suppress the occupant O from rolling during a lane change. ro The acceleration in the positive direction of the change can be controlled, and the deviation from the movement purpose originally required by the vehicle α can be suppressed before and after the lane change (i.e., based on the correction of the acceleration before and after A fr_c Therefore, the change in the roll direction of the occupant O during the lane change can be suppressed, and the influence on the movement state originally required for the vehicle α (unintentional speed change of the vehicle α) can be more reliably avoided.

[0090] In addition, if based on the above Figure 6 The logical correction of the acceleration before and after A fr_c The method for determining the direction of Figure 7 (b) shows the acceleration A before and after correction. fr_c The magnitude of the acceleration value |a| is irrelevant, but the acceleration A before and after correction can be fr_c The increase or decrease in speed during lane change (corrected front and rear acceleration A during lane change) fr_c The integral value of is approximately 0. Therefore, it is basically the same as the acceleration A before and after correction. fr_c The size of φ is irrelevant, and the influence on the motion state originally required by the vehicle α can be suppressed. ro The purpose is to change the acceleration value |a|, it is preferred to set the acceleration value to exceed the threshold value a when riding. th However, in this embodiment, as in the first embodiment, the correction of the longitudinal acceleration A is performed based on the suppression of the impact on the occupant O. fr_c From the perspective of the discomfort caused by the recognition of acceleration / deceleration, it is most preferable to set the set acceleration value |a| to a value that is equal to the threshold value a of the feeling when riding. th The same value.

[0091] Next, the effects of the vehicle motion control method will be described by comparing Examples 1 and 2 of the vehicle motion control method according to the present embodiment with a comparative example.

[0092] (Example 1)

[0093] The behavior of the posture change of the occupant O of the vehicle α constituted by an electric vehicle was simulated under the following conditions by applying the inverted pendulum model.

[0094] (i) Lane change conditions

[0095] The lane change time (the time from the start of the moving phase I to the end of the return phase II) is set to 4 seconds, and the basic longitudinal acceleration A is set so that the vehicle speeds before and after the lane change are substantially the same. fr_tb .

[0096] (ii) Corrected front and rear acceleration A fr_c

[0097] according to Figure 6 The control logic described in the previous section sets the corrected front and rear acceleration A. fr_c In particular, the basic forward and backward acceleration A in the moving phase I is fr_tb The setting is such that the vehicle is decelerated by the motor regeneration operation after about 0.5 seconds from the first movement stage I-1, and accelerated by the motor power operation in the second movement stage I-2. In addition, the basic front-to-back acceleration A in the return stage II is set to fr_tb It is set that the vehicle is decelerated by the motor regeneration operation after about 1 second from the first return phase II-1, and is accelerated by the motor power operation in the second return phase II-2. fr_c The magnitude (set acceleration value |a|) is set to 0.5 [m / s 2 ](Sensory threshold when riding a car th about twice as much).

[0098] (Example 2)

[0099] In addition to setting the acceleration value |a| to 0.25 [m / s 2 ](with the sensory threshold a when riding th The simulation was carried out under the same conditions as in Example 1 except that the above conditions were the same as those in Example 1.

[0100] (Comparative Example)

[0101] Do not perform front and rear acceleration and deceleration during lane change (correct the front and rear acceleration A fr_c The simulation was performed under the same conditions as in Example 1 and Example 2.

[0102] (Results and Investigation)

[0103] Figure 8 The simulation results of Example 1, Example 2 and Comparative Example are shown. In particular, Figure 8 (a)~ Figure 8 (c) represent the lateral acceleration A la Changes in acceleration A before and after correction fr_c The change of the roll attitude angle φ ro (Change in the tilt angle of the inverted pendulum).

[0104] As shown in the figure, compared with the comparative example, the roll attitude angle φ during lane change is suppressed in both embodiments 1 and 2. ro In addition, the acceleration A before and after correction is fr_c The magnitude (set acceleration value |a|) is greater than the sensory threshold a when riding a vehicle. th Embodiment 1, and setting the acceleration value |a| to be equal to the threshold value a of the feeling when riding th Compared with the embodiment 2 of the same degree, the roll attitude angle φ is suppressed ro The effect of the changes is slightly improved.

[0105] On the other hand, if the acceleration value |a| is set to be greater than the riding sensation threshold a as in the first embodiment, th , since the occupant O will recognize the acceleration or deceleration of the vehicle α, it is conceivable that the occupant O may feel uncomfortable. ro In order to reduce the effect of the change in the acceleration value |a| and reduce the possibility of causing discomfort to the occupant O, it is considered that it is most preferable to set the acceleration value |a| to be equal to the threshold value a of the feeling when riding the vehicle as in Example 2. th In particular, even in Example 2, the acceleration A is not corrected. fr_c Compared with the case of the comparative example, the roll attitude angle φ ro The amplitude is also reduced by at least 17%.

[0106] According to the vehicle motion control method of this embodiment having the above-described configuration, the following effects are achieved.

[0107] In this embodiment, the vehicle transition motion is set to the lateral acceleration A acting on the vehicle α. la In addition, the lateral acceleration A during the lane change la In the interval where the absolute value of decreases (the second moving stage I-2 and the second returning stage II-2), the front-to-back acceleration A is corrected. fr_c The direction is set to be the positive direction along the acceleration direction of vehicle α ( Figure 7 ).

[0108] Thus, during a lane change as a transitional movement of the vehicle over a certain period of time, it is possible to ensure a section in which an inertial force (inertial force toward the rear of the vehicle) acts to press the occupant O toward the seat S. Therefore, the function of ensuring friction between the occupant O and the seat S during the lane change can be exerted, and the change in the posture of the occupant O can be suppressed.

[0109] In particular, in this embodiment, the lateral acceleration A during the lane change la In the interval where the absolute value of increases (the first moving stage I-1 and the first returning stage II-1), the front-to-back acceleration A is corrected. fr_c The direction is set to the negative direction along the deceleration direction of vehicle α ( Figure 7 ).

[0110] Thus, during the lane change, a certain deceleration interval can be ensured to offset the corrected front-rear acceleration A set in the positive direction as described above. fr_c Therefore, since the change in vehicle speed before and after the lane change can be suppressed, the change in the posture of the occupant O can be suppressed, and the influence on the movement state originally required of the vehicle α can be avoided more reliably.

[0111] Furthermore, in this way, at the lateral acceleration A la In the interval where the absolute value of increases (the interval where a strong sense of acceleration or deceleration is generated), the front and rear acceleration A is corrected instead. fr_c By setting it to negative, an inertial force in a direction away from the seat S acts on the occupant O, which is presumably effective in causing the body of the occupant O to follow the motion of the vehicle. Therefore, it is expected that the occupant O will not easily feel the motion sensation and visual deviation that are the main causes of motion sickness.

[0112] In the present embodiment, the lateral acceleration A during the lane change is la The steering angle θ of the vehicle α is obtained by s and as the steering angle θ s The time derivative of the steering angular velocity ω s (Step S120 and Step S131). s and steering angular velocity ω s When the product of is positive, the corrected front and rear acceleration A in lane change is fr_c The direction is set to the negative direction along the deceleration direction of the vehicle α, and at the steering angle θ s and steering angular velocity ω s When the product of is negative, the corrected front and rear acceleration A in lane change is fr_c The direction of is set to be the positive direction along the acceleration direction of the vehicle α (Equations (1) and (2)).

[0113] Therefore, according to the lateral acceleration A during lane change la The change in the lane change (i.e., the degree of progress of the lane change) can maintain the function of ensuring the friction between the occupant O and the seat S, and realize the method for setting the appropriate modified front and rear acceleration A from the viewpoint of being able to more reliably avoid the influence of the required driving state of the vehicle α before and after the lane change. fr_c The operation logic of the direction.

[0114] Alternatively, the steering angle θ may be replaced by s and the steering angular velocity ω s , and the lateral acceleration A in lane change is obtained by la The detected value (hereinafter also referred to as the "lateral acceleration detected value A la_d ”) and the transverse impact jump J as its time differential value la A configuration as a parameter corresponding to the degree of progress of the lane change.

[0115] More specifically, the lateral acceleration A during lane change is la The change of the schematic quantity, obtain the lateral acceleration detection value A la_d and transverse impact jump J la , at the lateral acceleration detection value A la_d and transverse impact jump J la When the product of is positive, the corrected front and rear acceleration A in lane change is fr_c The direction is set to the negative direction along the deceleration direction of the vehicle α, and the lateral acceleration detection value A la_d and transverse impact jump J la When the product of is negative, the corrected front and rear acceleration A in lane change is fr_c The direction is set to be along the positive direction of the acceleration direction of the vehicle α (refer to Figure 7 (a)) is also a disclosed matter in the specification of this application, etc.

[0116] On the other hand, the steering angle θ s and steering angular velocity ω s In general electronically controlled steering systems, this is included in the sensor signal that is generally provided as standard. Moreover, in a vehicle transient motion in a linear region (a region where the tire lateral force is approximately proportional to the tire slip angle) such as a lane change, it is theoretically known that the steering angle θ s and the steering angular velocity ω s Respectively with the lateral acceleration A la And the lateral impact jump J la The waveforms are roughly the same. In addition, the lateral impact jump J la The lateral acceleration value A detected by the acceleration sensor needs to bela_d The differential is calculated, but since it contains a lot of noise, it requires a lot of effort to ensure its accuracy. Therefore, as an example of the lateral acceleration A in the lane change envisioned in this application, la The amount of change in the steering angle θ is more preferably used. s and the steering angular velocity ω s .

[0117] Although the embodiments of the present invention have been described above, the above embodiments and modifications merely represent a part of application examples of the present invention and are not intended to limit the technical scope of the present invention to the specific structures of the above embodiments.

[0118] For example, as described above, the vehicle α to which the vehicle motion control method of each of the above embodiments is applied can be applied to both an electric vehicle and an engine-driven vehicle. However, the vehicle motion control method of each of the above embodiments can be executed with higher accuracy by being applied to an electric vehicle that can accelerate and decelerate by more responsive electrical control such as power running control and regeneration control of an electric motor.

[0119] In the above embodiments, friction braking and regenerative braking are used as the travel actuator 14 for decelerating the vehicle α in the front-rear direction. However, the vehicle α may be decelerated by a mechanical structure (such as a structure that makes the internal resistance of the drive system variable).

[0120] Furthermore, in the second embodiment, the modified longitudinal acceleration A is set so that the vehicle speed change before and after the lane change is substantially zero. fr_c However, the present invention is not limited to this, and a control method can be adopted in which, although the vehicle speed increases or decreases slightly before and after the lane change, the vehicle speed increase can be suppressed compared with the case where the positive acceleration is continuously applied during the lane change (at least a part of the lane change includes correcting the front and rear acceleration A). fr_c Set to control the range below 0).

[0121] In the above-described embodiments, it is assumed that the controller 16 automatically controls the steering angle θ of the vehicle α during the lane change. s However, instead of this, the steering angle θ during lane change may be s In a vehicle α where the adjustment of the steering angle θ is performed manually by the driver operating the steering wheel, the control of each of the above embodiments is applied. s Based on the structure of adjustment, the steering angle θ corresponding to the degree of lane change is known in advance. sThe structure of the change can also omit the control for determining the modified front and rear acceleration A in the control of the above-mentioned embodiments. fr_c The feedback factor (steering angle θ s Thus, the control responsiveness can be further improved.

[0122] Furthermore, in the above-mentioned embodiments, an example is described in which the vehicle transition motion that generates lateral acceleration in the vehicle α is a lane change. However, even in the case of a vehicle transition motion other than a lane change, in the case of generating lateral acceleration that promotes the posture change in the roll direction of the occupant O, the vehicle motion control method of the above-mentioned embodiments can be applied with some changes. For example, not limited to lane changes, when a turn of the vehicle α is detected, the correction of the longitudinal acceleration A can also be adopted. fr_c A structure that is set to be positive and constant.

[0123] In the above-mentioned embodiments and modifications, the steering angle θ is used. s and steering angular velocity ω s , or lateral acceleration detection value A la_d and transverse impact jump J la As examples of parameters indicating the degree of progress of lane change, however, instead of these, the parameter indicating the degree of progress of lane change may be determined based on other physical quantities or external information.

[0124] Furthermore, the riding sensation threshold a assumed in each of the above embodiments is th The numerical range is not necessarily limited to the above specific values ​​(about 0.2 to 0.3 [m / s 2 ]). In particular, if the sensory threshold a is th It is higher than the standard sensory threshold (about 0.05 to about 0.1 [m / s 2 ]) can be set to an appropriate value within a range that can achieve the effect of preventing the occupant O from recognizing the acceleration or deceleration state, taking into account various factors (such as the specifications of the vehicle α or the assumed driving environment).

[0125] In addition, a vehicle motion control program for causing the controller 16 as a computer to execute the vehicle motion control method described in the above-mentioned embodiments, and a storage medium storing the vehicle motion control program are also included in the scope of matters described in the specification at the time of filing the present application.

Claims

1. A vehicle motion control method, in which the vehicle generates lateral acceleration during a vehicle transition motion, controls the motion state of the vehicle, wherein: setting a modified longitudinal acceleration for modifying a basic longitudinal acceleration determined according to a requested driving force for traveling the vehicle, determining a target front-rear acceleration based on the basic front-rear acceleration and the modified front-rear acceleration, and operating a travel actuator of the vehicle based on the target front-rear acceleration, The direction and magnitude of the modified longitudinal acceleration are determined from the viewpoint of suppressing a posture change of the occupant of the vehicle in the roll direction. In at least a portion of the transitional motion of the vehicle, the direction of the corrected longitudinal acceleration is set to be a positive direction along the forward direction of the vehicle, The vehicle transition motion is set as a change in lateral acceleration acting on the vehicle and a lane change corresponding to the degree of progress, In the lane change, according to the progress degree, a first moving stage in which the absolute value of the lateral acceleration increases, a second moving stage in which the absolute value of the lateral acceleration decreases, a first returning stage in which the absolute value of the lateral acceleration increases, and a second returning stage in which the absolute value of the lateral acceleration decreases are successively executed in sequence, In the first movement phase, the direction of the corrected front-rear acceleration is set to a negative direction along the deceleration direction of the vehicle, In the second movement phase, the direction of the corrected front-rear acceleration is set to be a positive direction along the acceleration direction of the vehicle, In the first return phase, the direction of the corrected front-rear acceleration is set to the negative direction, In the second returning phase, the direction of the corrected front-rear acceleration is set to the positive direction.

2. The vehicle motion control method according to claim 1, wherein: The magnitude of the correction front-back acceleration is set to a value corresponding to or close to a threshold of sensation during riding obtained by correcting a threshold of sensation of a person with respect to translational acceleration based on a running environment of the vehicle.

3. The vehicle motion control method according to claim 1 or 2, wherein: acquiring a steering angle of the vehicle and a steering angular velocity which is a time-differentiated value of the steering angle as indicative quantities of changes in the lateral acceleration during the lane change, When the product of the steering angle and the steering angular velocity is positive, the direction of the corrected longitudinal acceleration in the lane change is set to a negative direction along the deceleration direction of the vehicle, When the product of the steering angle and the steering angular velocity is negative, the direction of the corrected front-rear acceleration in the lane change is set to a positive direction along the acceleration direction of the vehicle.

4. The vehicle motion control method according to claim 1 or 2, wherein: acquiring a lateral acceleration detection value of the vehicle and a lateral impact jump as a time differential value of the lateral acceleration detection value as an indicative amount of the change in the lateral acceleration during the lane change, When the product of the lateral acceleration detection value and the lateral impact jerk is positive, the direction of the corrected front-rear acceleration in the lane change is set to a negative direction along the deceleration direction of the vehicle, When the product of the lateral acceleration detection value and the lateral jerk is negative, the direction of the corrected front-rear acceleration in the lane change is set to a positive direction along the acceleration direction of the vehicle.

5. A vehicle motion control device for controlling the motion state of a vehicle during a vehicle transition motion in which the vehicle generates lateral acceleration, wherein: The vehicle motion control device has: a setting unit that sets a modified longitudinal acceleration for modifying a basic longitudinal acceleration determined based on a requested driving force for traveling of the vehicle; an operating unit that determines a target longitudinal acceleration based on the basic longitudinal acceleration and the modified longitudinal acceleration, and operates a travel actuator of the vehicle based on the target longitudinal acceleration, The direction and magnitude of the modified longitudinal acceleration are determined from the viewpoint of suppressing a posture change of the occupant of the vehicle in the roll direction. In at least a portion of the transitional motion of the vehicle, the direction of the corrected longitudinal acceleration is set to be a positive direction along the forward direction of the vehicle, The vehicle transition motion is set as a change in lateral acceleration acting on the vehicle and a lane change corresponding to the degree of progress, In the lane change, according to the progress degree, a first moving stage in which the absolute value of the lateral acceleration increases, a second moving stage in which the absolute value of the lateral acceleration decreases, a first returning stage in which the absolute value of the lateral acceleration increases, and a second returning stage in which the absolute value of the lateral acceleration decreases are successively executed in sequence, In the first movement phase, the direction of the corrected front-rear acceleration is set to a negative direction along the deceleration direction of the vehicle, In the second movement phase, the direction of the corrected front-rear acceleration is set to be a positive direction along the acceleration direction of the vehicle, In the first return phase, the direction of the corrected front-rear acceleration is set to the negative direction, In the second returning phase, the direction of the corrected front-rear acceleration is set to the positive direction.

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