Vehicle control device and vehicle control method

Abstract

According to a vehicle control device of the present invention, in one aspect thereof, in a displaceable control range of an actuator that executes posture control including roll control and pitch control, a target posture characteristic indicating a target posture angle including a target roll angle and a target pitch angle, or a target displacement of the actuator, which suppresses a load applied to an occupant with respect to an arbitrary combination of longitudinal acceleration and lateral acceleration, is acquired, a target posture command is obtained on the basis of the target posture characteristic and a combination of the detected longitudinal acceleration and lateral acceleration, and posture control is executed on the basis of the target posture command. As a result, riding comfort can be improved as much as possible even in a situation where a roll and a pitch are generated in a composite manner.

Description

Vehicle control device and vehicle control method

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

[0002] The vehicle integrated control device of Patent Document 1 has a first target value generation unit that acquires a target momentum of a control axis related to a vehicle driving task and generates a first motion parameter, which is at least one motion parameter; a second target value generation unit that generates a second motion parameter different from the first motion parameter based on the first motion parameter so as to optimize a sensitivity index; a restriction generation unit that generates a motion restriction amount for the second motion parameter based on the first motion parameter and the operating range of the actuator; a final target generation unit that corrects the second motion parameter based on the motion restriction amount; and an operation amount allocation unit that determines the operation amount of the actuator based on the first motion parameter and the second motion parameter corrected by the final target generation unit.

[0003] Japanese Patent Application Laid-Open No. 2022-183594

[0004] However, when controlling the roll and pitch of a vehicle in order to reduce the load on vehicle occupants and improve ride comfort, in situations where roll and pitch occur in combination, a demand may arise that exceeds the control range of the actuator that controls the roll and pitch, and the operation of the actuator may be restricted, which could actually worsen ride comfort.

[0005] SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide a vehicle control device and a vehicle control method that can improve ride comfort as much as possible even in a situation where roll and pitch occur in combination.

[0006] In one aspect, the vehicle control device of the present invention acquires target attitude characteristics stored in a memory unit, which indicate target attitude angles including target roll angles and target pitch angles or target displacements of actuators that suppress the load on the occupant for any combination of longitudinal acceleration and lateral acceleration within a displaceable control range of the actuators that perform attitude control including roll control and pitch control, calculates a target attitude command based on the target attitude characteristics and the detected combination of longitudinal acceleration and lateral acceleration, and performs attitude control based on the target attitude command.

[0007] In one aspect, the vehicle control method according to the present invention is a vehicle control method executed by a control unit mounted on a vehicle, and when longitudinal acceleration occurs and increases in the vehicle while lateral acceleration is occurring in the vehicle, the method executes only roll control of the vehicle without executing pitch control of the vehicle for a predetermined period of time.

[0008] According to the present invention, it is possible to improve ride comfort as much as possible even in a situation where roll and pitch occur in combination.

[0009] FIG. 1 is a configuration diagram showing a vehicle control system. FIG. 1 is a functional block diagram of a vehicle control device that executes vehicle attitude control. FIG. 2 is a diagram showing one aspect of a map of a target pitch angle. FIG. 3 is a diagram showing one aspect of a map of a target roll angle. FIG. 4 is a diagram illustrating an example of a change in occupant moment with respect to pitch angle and roll angle. FIG. 5 is a diagram illustrating an example of a change in occupant moment with respect to pitch angle and roll angle. FIG. 6 is a time chart showing the operation of attitude control of an embodiment. FIG. 7 is a functional block diagram of a vehicle control device that sets a target displacement of an actuator. FIG. 8 is a diagram showing one aspect of a pitch control map that calculates a target stroke amount. FIG. 9 is a diagram showing one aspect of a roll control map that calculates a target stroke amount. FIG. 10 is a diagram illustrating an example of a difference in target attitude angle depending on tread and wheelbase. FIG. 11 is a diagram illustrating an example of a difference in target attitude angle depending on tread and wheelbase. FIG. 12 is a flowchart showing a process of selecting a target attitude characteristic in response to manual mode selection. FIG. 13 is a flowchart showing a process of selecting a target attitude characteristic in response to occupant recognition.

[0010]

[0023] Hereinafter, an embodiment of a vehicle control device and a vehicle control method according to the present invention will be described with reference to the drawings. Fig. 1 is a block diagram showing one aspect of a vehicle control system 200 mounted on a vehicle 100. The vehicle 100 is a four-wheeled automobile having a pair of left and right front wheels 101, 102 and a pair of left and right rear wheels 103, 104.

[0011] The vehicle control system 200 is a system that realizes a vehicle attitude control function, which is a function that actively controls the attitude of the vehicle 100, specifically the roll and pitch, in order to reduce the load applied to the occupants of the vehicle 100 and improve the comfort of the occupants. The vehicle control system 200 includes an acceleration sensor 400, a vehicle control device 500, and an active suspension 600. The acceleration sensor 400 outputs measurement signals of the longitudinal acceleration αx and lateral acceleration αy of the vehicle 100.

[0012] The active suspension 600 is a type of actuator that performs attitude control, including roll control and pitch control, of the vehicle 100. The active suspension 600 is a suspension device that can actively control the suspension stroke independently for each of the wheels 101-104, and is equipped with hydraulic, electromagnetic, or electrodynamic actuators 610A-610D for each of the wheels 101-104.

[0013] Active suspension 600 can control the roll and pitch of vehicle 100 by individually controlling actuators 610A-610D. Active suspension 600 also includes stroke sensors 611A-611D that detect the stroke amount (in other words, displacement) of the suspension of each wheel 101-104.

[0014] The vehicle control device 500 includes a microcomputer 510 as a control unit that outputs the results of calculations based on acquired information. The microcomputer 510 includes an MPU (Microprocessor Unit), a ROM (Read Only Memory), a RAM (Random Access Memory), and the like, all of which are not shown. The microcomputer 510 can also be referred to as an MCU (Micro Controller Unit), a processor, a processing device, an arithmetic device, or the like.

[0015] The microcomputer 510 of the vehicle control device 500 has, as a functional configuration, an acceleration detection unit that acquires the measurement signal output by the acceleration sensor 400 and detects the longitudinal acceleration αx and lateral acceleration αy of the vehicle 100. Note that the acceleration detection unit included in the microcomputer 510 may estimate the longitudinal acceleration αx and lateral acceleration αy from the motion state of the vehicle 100.

[0016] The microcomputer 510 then outputs a control command for operating the active suspension 600 through calculation processing based on the longitudinal acceleration αx and lateral acceleration αy of the vehicle 100, thereby controlling the roll and pitch of the vehicle 100 to reduce the load on the occupants. In other words, the microcomputer 510 is a control unit mounted on the vehicle 100 that executes a vehicle control method for controlling the roll and pitch of the vehicle 100.

[0017] 2 is a block diagram showing one aspect of the vehicle attitude control function of the microcomputer 510. The microcomputer 510 includes a target attitude calculation unit 520 and an attitude control unit 530 as functional units for vehicle attitude control.

[0018] The target attitude calculation unit 520 obtains the detected values ​​of the longitudinal acceleration αx and lateral acceleration αy of the vehicle 100 from the acceleration sensor 400, and outputs a signal of the target stroke amount for each wheel in the active suspension 600 as a target attitude command. The attitude control unit 530 obtains the target stroke amount signal from the target attitude calculation unit 520, and outputs control signals to the actuators 610A-610D of the active suspension 600, thereby performing attitude control including roll control and pitch control of the vehicle 100.

[0019] The target attitude calculation unit 520 has a target attitude angle calculation unit 521, which has a target pitch angle calculation unit 521A that calculates a target pitch angle θxtg [deg] and a target roll angle calculation unit 521B that calculates a target roll angle θytg [deg]. In other words, the target attitude angle calculation unit 521 calculates a target attitude angle including the target pitch angle θxtg and the target roll angle θytg.

[0020] Here, the target pitch angle calculation unit 521A refers to a target pitch angle map in which the target pitch angle θxtg is stored for each combination of the longitudinal acceleration αx and the lateral acceleration αy, and searches for the target pitch angle θxtg corresponding to the longitudinal acceleration αx and the lateral acceleration αy at that time. Similarly, the target roll angle calculation unit 521B refers to a target roll angle map in which the target roll angle θytg is stored for each combination of the longitudinal acceleration αx and the lateral acceleration αy, and searches for the target roll angle θytg corresponding to the longitudinal acceleration αx and the lateral acceleration αy at that time.

[0021] In other words, the target attitude angle calculation unit 521 uniquely determines the target pitch angle θxtg, which is the target attitude angle in pitch control, and the target roll angle θytg, which is the target attitude angle in roll control, for each combination of the longitudinal acceleration αx and the lateral acceleration αy. This makes it possible to optimize the target pitch angle θxtg and the target roll angle θytg for each combination of the longitudinal acceleration αx and the lateral acceleration αy, thereby making it possible to improve the ride comfort of the occupants as much as possible even in situations where roll and pitch occur in combination, such as when accelerating or decelerating while traveling on a curved road.

[0022] The map of target pitch angles referred to by the target pitch angle calculation unit 521A and the map of target roll angles referred to by the target roll angle calculation unit 521B are stored in advance in a storage unit configured as a nonvolatile memory such as a ROM of the microcomputer 510. In other words, the target attitude angle calculation unit 521 acquires the map of target pitch angles and the map of target roll angles as target attitude characteristics stored in the storage unit such as a ROM, and determines a target attitude command based on a combination of the map of target pitch angles and the map of target roll angles and the detected longitudinal acceleration αx and lateral acceleration αy.

[0023] The target pitch angle calculation unit 521A and the target roll angle calculation unit 521B can calculate the target pitch angle θxtg and the target roll angle θytg based on functions with the longitudinal acceleration αx and the lateral acceleration αy as variables. In this case, the functions for calculating the target pitch angle θxtg and the target roll angle θytg are stored as control programs in a storage unit such as the ROM of the microcomputer 510.

[0024] 3 shows one example of a map of a target pitch angle as a target attitude characteristic. The target pitch angle map uniquely defines, as a characteristic value, a target pitch angle θxtg that suppresses the load on the occupants of vehicle 100 for any combination of longitudinal acceleration αx and lateral acceleration αy within the control range in which actuators 610A-610D of active suspension 600 can be displaced, i.e., within the variable range of the suspension stroke.

[0025] 4 shows one example of a map of a target roll angle as a target attitude characteristic. The target roll angle map uniquely defines, as a characteristic value, a target roll angle θytg that suppresses the load on the occupants of vehicle 100 for any combination of longitudinal acceleration αx and lateral acceleration αy within the control range in which actuators 610A-610D of active suspension 600 can be displaced. In other words, the target pitch angle map and the target roll angle map are set so as to allocate requests for roll control and pitch control within the control range in which actuators 610A-610D of active suspension 600 can be displaced for any combination of longitudinal acceleration αx and lateral acceleration αy, thereby minimizing the load on the occupants.

[0026] Here, the target pitch angle map and the target roll angle map are set to have characteristics such that the absolute value of the target pitch angle θxtg decreases and the absolute value of the target roll angle θytg increases as the lateral acceleration αy increases when longitudinal acceleration αx is occurring. Such target attitude angle setting characteristics are suitable for suppressing the occupant moment in a general vehicle 100 whose wheelbase is longer than its tread. Note that in a special vehicle whose wheelbase is shorter than its tread, control characteristics opposite to those described above are required.

[0027] The sine calculation unit 522A obtains the target pitch angle θxtg calculated by the target pitch angle calculation unit 521A and calculates the sine of the target pitch angle θxtg (sin(θxtg)). The stroke amount conversion unit 523A then multiplies the sine of the target pitch angle θxtg (sin(θxtg)) by the wheelbase L [mm] of the vehicle 100 to calculate the target stroke amount Sptg [mm] of the suspension that corresponds to the target pitch angle θxtg.

[0028] Furthermore, the sine calculation unit 522B acquires the target roll angle θytg calculated by the target roll angle calculation unit 521B, and calculates the sine of the target roll angle θytg (sin(θytg)). The stroke amount conversion unit 523B then multiplies the sine of the target roll angle θytg (sin(θytg))) by the tread T [mm] of the vehicle 100 to calculate the target stroke amount Srtg [mm] of the suspension corresponding to the target roll angle θytg.

[0029] The adder 524 adds the target stroke amount Sptg for achieving the target pitch angle θxtg, obtained by the stroke amount converter 523A, and the target stroke amount Srtg for achieving the target roll angle θytg, obtained by the stroke amount converter 523B, to obtain a final target stroke amount Stg for each wheel.The adder 524 then outputs a signal of the target stroke amount Stg for each wheel to the attitude controller 530.

[0030] The posture control unit 530 has the following functional units: a deviation calculation unit 531, a load calculation unit 532, and a load-current conversion unit 533. The deviation calculation unit 531 acquires a signal of the target stroke amount Stg from the adder 524 of the target posture calculation unit 520, and also acquires a signal of the actual stroke amount Sac of each wheel from the stroke sensors 611A-611D. The deviation calculation unit 531 then determines the deviation ΔS between the target stroke amount Stg and the actual stroke amount Sac for each wheel.

[0031] The load calculation unit 532 calculates the required load for each of the actuators 610A-610D of the active suspension 600 by multiplying the deviation ΔS between the target stroke amount Stg and the actual stroke amount Sac, calculated by the deviation calculation unit 531, by the control gain G. The load-to-current conversion unit 533 converts the signal of the required load for each of the actuators 610A-610D, calculated by the load calculation unit 532, into a command value for the current to be applied to each of the actuators 610A-610D, in other words, a target current value, by referring to a conversion table. The load-to-current conversion unit 533 then outputs a control current corresponding to the target current value to the actuators 610A-610D of the active suspension 600.

[0032] The following describes in detail the process of adapting the target attitude characteristics, in other words, the target pitch angle map and the target roll angle map. The target attitude characteristics are adapted so that a target roll angle θytg and a target pitch angle θxtg are set that can minimize the load on the occupant of the vehicle 100 (hereinafter referred to as occupant moment PM) within the controllable range of the actuators 610A-610D of the active suspension 600 for any combination of the longitudinal acceleration αx and the lateral acceleration αy of the vehicle 100. Note that the occupant moment PM includes the roll moment and pitch moment generated on the occupant due to the forces acting on the occupant from the behavior of the vehicle 100.

[0033] 5 and 6 are diagrams illustrating a method for determining the roll angle θy and pitch angle θx that can minimize the occupant moment PM for any combination of the longitudinal acceleration αx and lateral acceleration αy of the vehicle 100. FIG. 5 shows how the occupant moment PM changes depending on the combination of the roll angle θy and the pitch angle θx when the longitudinal acceleration αx is a predetermined value αx1 and the lateral acceleration αy is a predetermined value αy1. From FIG. 5, it is possible to determine the combination of the roll angle θy and the pitch angle θx that minimizes the occupant moment PM within the control range in which the actuators 610A-610D can be displaced when the longitudinal acceleration αx is a predetermined value αx1 and the lateral acceleration αy is a predetermined value αy1.

[0034] Similarly, Figure 6 shows how the occupant moment PM changes depending on the combination of the roll angle θy and the pitch angle θx when the longitudinal acceleration αx is a predetermined value αx2 and the lateral acceleration αy is a predetermined value αy2, that is, when the combination of the longitudinal acceleration αx and the lateral acceleration αy is different from that shown in Figure 5. Figure 6 also shows the combination of the roll angle θy and the pitch angle θx that minimizes the occupant moment PM within the control range in which the actuators 610A-610D can be displaced when the longitudinal acceleration αx is a predetermined value αx2 and the lateral acceleration αy is a predetermined value αy2.

[0035] In this way, it is possible to determine the combination of roll angle θy and pitch angle θx that minimizes the occupant moment PM for each arbitrary combination of longitudinal acceleration αx and lateral acceleration αy. Therefore, a map of target roll angles with longitudinal acceleration αx and lateral acceleration αy as variables is generated and stored in the ROM of the microcomputer 510 so that the roll angle θy that minimizes the occupant moment PM for each arbitrary combination of longitudinal acceleration αx and lateral acceleration αy can be retrieved as the target roll angle θytg.

[0036] Similarly, a map of target pitch angles with the longitudinal acceleration αx and the lateral acceleration αy as variables is generated and stored in the ROM of the microcomputer 510 so that the pitch angle θx at which the occupant moment PM is minimized for each arbitrary combination of the longitudinal acceleration αx and the lateral acceleration αy is searched for as the target pitch angle θxtg. Then, the target pitch angle calculation unit 521A and the target roll angle calculation unit 521B of the target attitude angle calculation unit 521 refer to the target pitch angle map and the target roll angle map stored in the ROM as a storage unit, and calculate the target pitch angle θxtg and the target roll angle θytg at which the occupant moment PM is minimized for the longitudinal acceleration αx and the lateral acceleration αy at that time.

[0037] Therefore, according to the above vehicle attitude control, even in a situation where roll and pitch occur in combination, such as when accelerating or decelerating while traveling on a curved road, the occupant moment PM can be kept as small as possible, thereby improving occupant comfort. For example, if a roll attitude command based on the lateral acceleration αy and a pitch attitude command based on the longitudinal acceleration αx are set separately, in a situation where roll and pitch occur in combination, the required suspension stroke amount based on the roll attitude command and the required suspension stroke amount based on the pitch attitude command may overlap, causing the required stroke amount to exceed the variable range.

[0038] In this case, if the actual stroke amount is limited within the variable range, the attitude of the vehicle 100 cannot be optimally controlled, which may increase the occupant moment PM and make it difficult to stably ensure the comfort of the occupants. In contrast, according to the above-described vehicle attitude control, the target pitch angle θxtg and the target roll angle θytg are set based on the longitudinal acceleration αx and the lateral acceleration αy, so that in a situation where roll and pitch occur in combination, a required stroke amount that takes both roll and pitch into consideration can be allocated within the variable range, thereby making it possible to stably ensure the comfort of the occupants.

[0039] 7 is a time chart illustrating an example of changes in the target pitch angle θxtg and the target roll angle θytg in a scene where roll and pitch occur in combination. The arrows in the time chart showing changes in the pitch angle in Fig. 7 indicate the timing at which the absolute value of the target pitch angle θxtg, which is set based on the longitudinal acceleration αx and the lateral acceleration αy, becomes smaller than the absolute value of the target pitch angle θxtg, which is set based only on the longitudinal acceleration αx.

[0040] 7 indicates the timing at which the absolute value of the target roll angle θytg set based on the longitudinal acceleration αx and the lateral acceleration αy becomes larger than the absolute value of the target roll angle θytg set based on the lateral acceleration αy alone. According to the control that sets the target pitch angle θxtg and the target roll angle θytg based on the distribution of each combination of the longitudinal acceleration αx and the lateral acceleration αy, the occupant moment PM is suppressed to a smaller value than when the target pitch angle θxtg and the target roll angle θytg are set by individual pitch / roll control.

[0041] 7, the situation is one in which longitudinal acceleration αx occurs and increases in the vehicle 100 while lateral acceleration αy occurs in the vehicle 100. During this period from time t1 to time t2, the absolute value of the target pitch angle θxtg, which is set based on the longitudinal acceleration αx and the lateral acceleration αy, becomes smaller than the absolute value of the target pitch angle θxtg, which is set based on only the longitudinal acceleration αx, and the absolute value of the target roll angle θytg, which is set based on the longitudinal acceleration αx and the lateral acceleration αy, becomes larger than the absolute value of the target roll angle θytg, which is set based on only the lateral acceleration αy.

[0042] As a result, during the predetermined time period from time t1 to time t2, pitch control and roll control are executed in the pitch / roll individual control, whereas in the setting of the target pitch angle θxtg based on the longitudinal acceleration αx and the lateral acceleration αy, pitch control is hardly executed and only roll control is executed. In other words, the control characteristics from time t1 to time t2 become a control pattern specific to the process of setting the target pitch angle θxtg and the target roll angle θytg based on the longitudinal acceleration αx and the lateral acceleration αy, suggesting that the target pitch angle θxtg and the target roll angle θytg are set based on the longitudinal acceleration αx and the lateral acceleration αy.

[0043] In vehicle attitude control, the microcomputer 510 can directly calculate a target stroke amount Sptg equivalent to a target pitch angle θxtg and a target stroke amount Srtg equivalent to a target roll angle θytg as target attitude commands from the longitudinal acceleration αx and the lateral acceleration αy. Figure 8 is a functional block diagram of the microcomputer 510 configured to directly calculate the target stroke amount Sptg and the target stroke amount Srtg as target displacements of the actuators from the longitudinal acceleration αx and the lateral acceleration αy. In Figure 8, the same blocks as those in Figure 2 are designated by the same reference numerals, and detailed description thereof will be omitted.

[0044] 2 , the target attitude calculation unit 550 obtains detection values ​​of the longitudinal acceleration αx and lateral acceleration αy of the vehicle 100 from the acceleration sensor 400, and outputs a signal of the target stroke amount Stg of each wheel in the active suspension 600 as a target attitude command. Here, the target attitude calculation unit 550 has a pitch control unit 551A that directly calculates a target stroke amount Sptg for pitch control from the longitudinal acceleration αx and lateral acceleration αy, a roll control unit 551B that directly calculates a target stroke amount Srtg for roll control from the longitudinal acceleration αx and lateral acceleration αy, and an adder 552 that adds the target stroke amount Sptg and the target stroke amount Srtg to calculate a final target stroke amount Stg for each wheel.

[0045] The pitch control unit 551A refers to a pitch control map stored in a storage unit such as a ROM (or based on a function stored in a storage unit such as a ROM) to search for a target stroke amount Sptg corresponding to the longitudinal acceleration αx and lateral acceleration αy at that time. Similarly, the roll control unit 551B refers to a roll control map stored in a storage unit such as a ROM (or based on a function stored in a storage unit such as a ROM) to search for a target stroke amount Srtg corresponding to the longitudinal acceleration αx and lateral acceleration αy at that time.

[0046] 9 shows one example of a pitch control map that uniquely determines a target stroke amount Sptg, which is a target displacement of the actuator, for each combination of longitudinal acceleration αx and lateral acceleration αy. The target stroke amount Sptg for each combination of longitudinal acceleration αx and lateral acceleration αy in the pitch control map is the same as the target stroke amount Sptg obtained by the target pitch angle calculation unit 521A, sine calculation unit 522A, and stroke amount conversion unit 523A in the target attitude calculation unit 520 in FIG. 2. In other words, the pitch control map is obtained by inputting the target stroke amount Sptg obtained by the target pitch angle calculation unit 521A, sine calculation unit 522A, and stroke amount conversion unit 523A in FIG. 2 for each combination of longitudinal acceleration αx and lateral acceleration αy.

[0047] Fig. 10 shows one example of a roll control map that uniquely determines a target stroke amount Srtg, which is a target displacement of the actuator, for each combination of longitudinal acceleration αx and lateral acceleration αy. The target stroke amount Srtg for each combination of longitudinal acceleration αx and lateral acceleration αy in the roll control map is the same as the target stroke amount Srtg obtained by the target roll angle calculation unit 521B, sine calculation unit 522B, and stroke amount conversion unit 523B in the target attitude calculation unit 520 in Fig. 2. In other words, the roll control map is obtained by inputting the target stroke amount Sptg obtained by the target roll angle calculation unit 521B, sine calculation unit 522B, and stroke amount conversion unit 523B in Fig. 2 for each combination of longitudinal acceleration αx and lateral acceleration αy.

[0048] Therefore, in the attitude control using the functional blocks of Figure 8, the characteristics of the pitch angle θx and the roll angle θy with respect to the combination of the longitudinal acceleration αx and the lateral acceleration αy are the same as those in the attitude control using the functional blocks of Figure 2, and as the lateral acceleration αy increases when the longitudinal acceleration αx is generated, the absolute value of the pitch angle θx decreases and the absolute value of the roll angle θy increases. In addition, in the attitude control using the functional blocks of Figure 8, it is possible to improve ride comfort as much as possible in situations where roll and pitch occur in combination, and it is also possible to simplify the control calculations compared to when the control blocks of Figure 2 are used.

[0049] Incidentally, even with the same tread, the effect of pitch control becomes greater as the wheelbase becomes shorter, and in the case of a vehicle 100 with a short wheelbase, the effect of reducing the occupant moment PM can be maximized by increasing the pitch control amount compared to a vehicle 100 with a long wheelbase. For this reason, it is preferable that the target pitch angle map and the target roll angle map referenced in the control block of Figure 2 be adapted taking into account vehicle information including the tread and wheelbase of the vehicle 100.

[0050] 11 and 12 illustrate examples of differences in the characteristics of the target pitch angle θxtg and the target roll angle θytg due to differences in wheelbase. Note that Fig. 11 illustrates an example of a target pitch angle map and a target roll angle map suitable for a vehicle 100 having a tread of 1500 mm and a wheelbase of 2700 mm, and Fig. 12 illustrates an example of a target pitch angle map and a target roll angle map suitable for a vehicle 100 having a tread of 1500 mm and a wheelbase of 1500 mm.

[0051] The absolute value of the target pitch angle θxtg for the vehicle 100 having a short wheelbase shown in Fig. 12 is set to be larger than the absolute value of the target pitch angle θxtg for the vehicle 100 having a long wheelbase shown in Fig. 11. In this way, by changing the absolute value of the target pitch angle θxtg for the combination of the longitudinal acceleration αx and the lateral acceleration αy, i.e., the pitch control amount, in accordance with the length of the wheelbase, it is possible to minimize the occupant moment PM in the vehicle 100 having a short wheelbase, where the pitch control effect is large.

[0052] Incidentally, the microcomputer 510 is provided with a plurality of target attitude characteristics, such as a map of a target roll angle and a map of a target pitch angle, and can select and acquire a target attitude characteristic from the plurality of target attitude characteristics that corresponds to the control mode of the vehicle 100. In other words, the microcomputer 510 is not limited to a configuration that controls pitch and roll so as to minimize the occupant moment PM for a combination of the longitudinal acceleration αx and the lateral acceleration αy, but can select a target attitude characteristic in accordance with the control mode of the vehicle 100 from among control characteristics that minimize the occupant moment PM, control characteristics that allow the occupant moment PM to a certain extent, and the like.

[0053] Fig. 13 is a flowchart showing one example of a process for selecting a target attitude characteristic according to a control mode. The process for selecting a target attitude characteristic shown in the flowchart of Fig. 13 is a process in which three types of combinations of target roll angle maps and target pitch angle maps (map (A), map (B), and map (C)) are provided, and the combination of maps used for setting the target pitch angle θxtg and the target roll angle θytg is switched from among these three types in accordance with the control mode manually selected by the occupant. The control mode is, for example, a driving mode such as an autonomous driving mode, a sport mode, or a comfort mode.

[0054] In step S801, microcomputer 510 determines whether an AD (Autonomous Driving) mode switch that causes vehicle 100 to be driven autonomously is on, which indicates the implementation of autonomous driving, that is, whether the driver, who is an occupant of vehicle 100, has selected the autonomous driving mode. Here, if the AD mode switch is on and vehicle 100 is being driven autonomously, microcomputer 510 proceeds to step S802.

[0055] In step S802, microcomputer 510 selects map (A) from among three combinations of maps of target roll angles and maps of target pitch angles. Map (A) is the combination that is optimal for autonomous driving, of the three combinations of maps of target roll angles and maps of target pitch angles, in other words, the combination of maps that provides optimal roll / pitch control characteristics for autonomous driving, for example, the combination that can minimize occupant moment PM.

[0056] On the other hand, if the AD mode switch is off and vehicle 100 is being driven manually rather than automatically, that is, if the driver has selected the manual driving mode, microcomputer 510 proceeds to step S803. In step S803, microcomputer 510 determines whether or not the driving mode A switch that selects driving mode A in manual driving is on, that is, whether or not the driver has selected manual driving in driving mode A.

[0057] If the driving mode A switch is on and the driver has selected to implement vehicle control in a control mode according to driving mode A, microcomputer 510 proceeds to step S804 and selects map (B) from among the three combinations of maps of target roll angles and maps of target pitch angles. Note that vehicle control in the control mode according to driving mode A includes control of gear shift patterns, etc. If the driving mode A switch is off and vehicle control in driving mode A is not being implemented, in other words, if the driver has not selected driving mode A but has selected a default driving mode, for example, normal mode, microcomputer 510 proceeds to step S805 and selects map (C) from among the three combinations of maps of target roll angles and maps of target pitch angles.

[0058] Here, the driving mode A is, for example, a sport mode or a comfort mode, and the map (B) is the optimum combination for the driving mode A among three combinations of the map of the target roll angle and the map of the target pitch angle. For example, if the driving mode A is the sport mode, the map (B) selected for the driving mode A is a map that allows a larger occupant moment than the map selected in the normal mode. Also, if the driving mode A is the comfort mode, the map (B) selected for the driving mode A is a map that can suppress the occupant moment to a smaller extent than the map selected in the normal mode.

[0059] That is, the microcomputer 510 selects and acquires the target attitude characteristics corresponding to the control mode selected by the occupant by operating the AD mode switch, the driving mode A switch, etc., in other words, the driving mode and the driving mode, that is, the combination of the target roll angle map and the target pitch angle map. Then, by selecting the target attitude characteristics, vehicle attitude control suited to the occupant's preference and the driving environment is performed.

[0060] The selection of the target posture characteristic is not limited to being performed in response to the manual selection of the control mode by the occupant, but the microcomputer 510 can automatically select the target posture characteristic based on the determination result of the control mode based on the recognition result of the occupant, the driving environment, etc. Fig. 14 is a flowchart showing the automatic map switching process based on the recognition result of the occupant.

[0061] In step S811, microcomputer 510 identifies which of a plurality of pre-registered individuals the occupant of vehicle 100 corresponds to, for example, from an occupant image captured by a camera installed inside vehicle 100, such as a facial image of the driver sitting in the driver's seat. Next, in step S812, microcomputer 510 determines whether the identified occupant is occupant A who has been registered in advance.

[0062] Here, if the occupant of vehicle 100 is occupant A, in other words, if the control mode is for occupant A, microcomputer 510 proceeds to step S813 and selects map (A) that has been pre-registered as being suitable for occupant A as the map to be used for vehicle attitude control, i.e., the target attitude characteristics. On the other hand, if the occupant of vehicle 100 is not occupant A, microcomputer 510 determines in step S814 whether the identified occupant is occupant B, who has been pre-registered.

[0063] If the occupant of vehicle 100 is occupant B, in other words, if the control mode is for occupant B, microcomputer 510 proceeds to step S815 and selects map (B), which is pre-registered as being suitable for occupant B, as the map to be used for vehicle attitude control, i.e., the target attitude characteristics. If the occupant of vehicle 100 is neither pre-registered occupant A nor B, in other words, if the control mode is for a standard occupant, microcomputer 510 proceeds to step S816 and selects map (C), which is pre-registered as being suitable for a standard occupant, as the map to be used for vehicle attitude control, i.e., the target attitude characteristics.

[0064] The maps (A) and (B) adapted to the individual may be maps learned from the past map selections and mode selection tendencies of occupants A and B, or the driving characteristics of occupants A and B when they perform driving operations, or may be maps that occupants A and B have selected, adapted, and registered themselves according to their own preferences. The occupants themselves may select and adapt the maps by using, for example, an application for selecting and creating maps.

[0065] Furthermore, the method of personal identification executed by the microcomputer 510 is not limited to face authentication, and known identification methods such as fingerprint authentication or iris authentication can be appropriately adopted. Furthermore, the multiple types of maps that are selectively used can be stored in advance in the ROM of the microcomputer 510, or can be registered in a cloud as an external storage unit, and the microcomputer 510 can selectively obtain a map corresponding to the control mode at that time from the cloud via the Internet.

[0066] Furthermore, microcomputer 510 can automatically select a map according to the driving environment of vehicle 100, which includes weather, road conditions, etc. For example, map selection according to weather includes map selection according to conditions related to the friction coefficient of the road surface, such as sunny, rainy, or snowy weather, and the map selected in the control mode when it is sunny and the friction coefficient is high can be different from the map selected in the control mode when it is raining or snowing and the friction coefficient is low.

[0067] Furthermore, map selection according to road conditions includes map selection according to whether the road is a highway or an ordinary road, or whether the road is paved or unpaved. For example, a map selected in a control mode when vehicle 100 is traveling on an expressway may be different from a map selected in a control mode when vehicle 100 is traveling on an ordinary road. Microcomputer 510 can obtain information about the traveling environment from map information of a navigation device provided in vehicle 100, images from a camera for obtaining information about the external environment of vehicle 100, or the like, and can also obtain information from the outside via road-to-vehicle communication or vehicle-to-vehicle communication.

[0068] The technical ideas described in the above embodiments can be used in appropriate combinations as long as no contradictions arise. Furthermore, although the contents of the present invention have been specifically described with reference to preferred embodiments, it is obvious that a person skilled in the art can adopt various modified embodiments based on the basic technical ideas and teachings of the present invention.

[0069] The actuators that perform attitude control, including roll control and pitch control, of vehicle 100 are not limited to actuators 610A-610D of active suspension 600. For example, in a vehicle in which the braking / driving force can be controlled individually for each wheel, such as a vehicle equipped with an in-wheel motor for each wheel, attitude control, including roll control and pitch control, can be performed by adjusting the jack-up force and jack-down force generated at each wheel by controlling the braking / driving force applied to each wheel.

[0070] In this case, the in-wheel motors correspond to actuators that perform attitude control, including roll control and pitch control, of the vehicle. The microcomputer 510 controls the braking / driving forces applied to each wheel based on the target attitude characteristics set based on the longitudinal acceleration αx and the lateral acceleration αy, thereby realizing the target attitude characteristics (in other words, the target attitude angle).

[0071] Furthermore, the microcomputer 510 can perform attitude control including roll control and pitch control by combining control of the actuators 610A-610D of the active suspension 600 with control of the braking / driving force applied to each wheel. The microcomputer 510 can also correct the standard target attitude characteristics stored in the memory unit according to the control mode, etc., and use the corrected characteristics in calculating the target attitude command.

[0072] 100... Vehicle, 200... Vehicle control system, 400... Acceleration sensor, 500... Vehicle control device, 510... Microcomputer (control unit), 600... Active suspension, 610A-610D... Actuators

Claims

1. A vehicle control device comprising: an acceleration detection unit that detects longitudinal acceleration and lateral acceleration of a vehicle; an acceleration detection unit that detects longitudinal acceleration and lateral acceleration of the vehicle; a target attitude characteristic that acquires, stored in a memory unit, a target attitude angle including a target roll angle and a target pitch angle, or a target displacement of the actuator, which suppresses the load on an occupant of the vehicle for any combination of longitudinal acceleration and lateral acceleration of the vehicle within a displaceable control range of the actuator that performs attitude control including roll control and pitch control of the vehicle; a target attitude calculation unit that calculates a target attitude command based on the target attitude characteristic and the detected combination of longitudinal acceleration and lateral acceleration of the vehicle; and an attitude control unit that performs the attitude control based on the target attitude command.

2. A vehicle control device according to claim 1, wherein the target attitude calculation unit determines, as the target attitude command, a characteristic value corresponding to a combination of the detected longitudinal acceleration and lateral acceleration of the vehicle in the target attitude characteristics.

3. A vehicle control device according to claim 1, wherein the memory unit stores the target attitude characteristics as the target attitude angle that decreases the absolute value of the target pitch angle and increases the absolute value of the target roll angle as the lateral acceleration increases while the longitudinal acceleration is occurring.

4. A vehicle control device according to claim 1, wherein the memory unit stores the target attitude characteristics as target displacements of the actuator that decrease the absolute value of the target pitch angle and increase the absolute value of the target roll angle as the lateral acceleration increases while the longitudinal acceleration is occurring.

5. A vehicle control device according to claim 1, wherein the storage unit stores the target attitude characteristics calculated by adding vehicle information including the wheelbase and tread of the vehicle.

6. A vehicle control device according to claim 1, wherein the storage unit stores a plurality of target attitude characteristics, and the target attitude calculation unit selects and acquires the target attitude characteristic corresponding to the control mode of the vehicle from among the plurality of target attitude characteristics.

7. A vehicle control method executed by a control unit mounted on a vehicle, wherein, when longitudinal acceleration occurs and increases in the vehicle while lateral acceleration is occurring in the vehicle, pitch control of the vehicle is not executed for a predetermined time, and only roll control of the vehicle is executed.

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