Vehicle and vehicle suspension control method

Abstract

To realize posture control capable of improving comfort when a vehicle is in an automatic operation mode taking into consideration a drive feeling in a manual operation mode in the vehicle enabling the manual operation mode and the automatic operation mode to be switched.SOLUTION: A vehicle comprises one or a plurality of actuators which can be switched between a manual operation mode and an automatic operation mode and controls a suspension stroke of a control object wheel and an electronic control unit. The electronic control unit executes: a calculation process to calculate a demand control amount for executing at least either vehicle roll control or vehicle pitch control; and an instruction process to instruct the one or the plurality of actuators to output the demand control amount. In the calculation process, the electronic control unit makes a control gain included in the demand control amount larger in the automatic operation mode than in the manual operation mode.SELECTED DRAWING: Figure 5

Description

[Technical field]

[0001] The present disclosure relates to a vehicle equipped with one or more actuators that control a suspension stroke and capable of switching between a manual driving mode and an autonomous driving mode, and a method for controlling a suspension for a vehicle. [Background technology]

[0002] Patent Document 1 discloses a technique for controlling active suspension based on information regarding the travel path of wheels received from an autonomous driving controller. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] US Patent Application Publication No. 2018 / 0154723 Summary of the Invention [Problem to be solved by the invention]

[0004] In a vehicle equipped with an actuator that controls the suspension stroke, the actuator can be used to actively control at least one of the roll and pitch of the vehicle. In such posture control (at least one of roll control and pitch control), the effect of the posture control can be increased by increasing the control gain included in the required control amount for the posture control, thereby improving the comfort of the vehicle.

[0005] Here, the attitude control during manual driving by the driver is required to be performed taking into consideration the driving feel of the driver. For this reason, it is difficult to increase the control gain in the attitude control during manual driving. Therefore, in the attitude control of a vehicle that can switch between a manual driving mode and an automatic driving mode, it is required to improve the comfort in the automatic driving mode while taking into consideration the driving feel in the manual driving mode.

[0006] The present disclosure has been made in consideration of the above-mentioned problems, and its purpose is to realize attitude control in a vehicle that can switch between manual driving mode and autonomous driving mode, which can improve comfort in autonomous driving mode while taking into account the driving feel in manual driving mode. [Means for solving the problem]

[0007] A vehicle according to the present disclosure is capable of switching between a manual driving mode and an automatic driving mode, and includes one or more actuators that control the suspension stroke of a controlled wheel, and an electronic control unit. The electronic control unit executes a calculation process that calculates a required control amount for at least one of roll control and pitch control of the vehicle, and a command process that commands the required control amount to one or more actuators. In the calculation process, the electronic control unit increases a control gain included in the required control amount in the automatic driving mode compared to the manual driving mode.

[0008] In the calculation process in the autonomous driving mode, the electronic control unit may set an upper limit on the roll rate based on future operation information of the vehicle obtained during autonomous driving control in the autonomous driving mode, and determine a control gain so that one or more actuators generate maximum control force within a range in which the roll rate does not exceed the upper limit.

[0009] In the calculation process in the autonomous driving mode, the electronic control unit may set an upper limit on the pitch rate based on future operation information of the vehicle obtained during autonomous driving control in the autonomous driving mode, and determine a control gain so that one or more actuators generate maximum control force within a range in which the pitch rate does not exceed the upper limit.

[0010] In the calculation process in the autonomous driving mode, the electronic control unit may perform low-pass filter processing on future operation information of the vehicle obtained during autonomous driving control in the autonomous driving mode, and calculate the required control amount based on the future operation information after the low-pass filter processing.

[0011] In the command processing, when low-pass filtering is performed, the electronic control unit may advance the timing of issuing a command of the required control amount to one or more actuators, compared to when low-pass filtering is not performed.

[0012] The one or more actuators may include a first actuator and a second actuator having higher responsiveness than the first actuator. In the command process, when a first maximum control amount, which is a maximum value of a first control amount that the first actuator can output, is insufficient for a required control amount, the electronic control unit may command the first actuator to the first maximum control amount and may command the second actuator to a second control amount to compensate for the shortage.

[0013] The present disclosure relates to a method for controlling a vehicle suspension, which is provided with one or more actuators for controlling a suspension stroke of a controlled wheel in a vehicle capable of switching between a manual driving mode and an autonomous driving mode. The control method includes a calculation process for calculating a required control amount for at least one of roll control and pitch control of the vehicle, and a command process for commanding the required control amount to one or more actuators. In the calculation process, a control gain included in the required control amount is made larger in the autonomous driving mode than in the manual driving mode. Effect of the Invention

[0014] According to the vehicle and vehicle suspension control method of the present disclosure, the control gain included in the required control amount is larger in the automatic driving mode than in the manual driving mode. While the attitude control in the manual driving mode needs to take into account the driving feel of the driver, in the automatic driving mode, the driving feel does not need to be taken into account. According to the present disclosure, by changing the control gain between the manual driving mode and the automatic driving mode, it is possible to realize attitude control (at least one of roll control and pitch control) that can improve comfort in the automatic driving mode while taking into account the driving feel in the manual driving mode. [Brief description of the drawings]

[0015] [Figure 1] 1 is a diagram illustrating an example of a configuration of a vehicle according to a first embodiment. [Diagram 2] 1 is a conceptual diagram showing a configuration example of a suspension according to a first embodiment. [Diagram 3] 1 is a block diagram showing an example of the configuration of a vehicle control system according to a first embodiment. [Figure 4] 2 is a block diagram showing an example of driving environment information indicating the driving environment of a vehicle 1. FIG. [Diagram 5] 4 is a flowchart showing a process related to attitude control according to the first embodiment. [Figure 6] FIG. 11 is a diagram for explaining an example of a method for calculating a required control amount Xr for roll control and a required control amount Xp for pitch control. [Figure 7] 10 is a flowchart showing a process related to attitude control according to the second embodiment. [Figure 8] FIG. 11 is a diagram illustrating an example of a configuration of a suspension provided on a vehicle according to a third embodiment. [Figure 9] 13 is a flowchart showing a process relating to attitude control according to the third embodiment. [Figure 10] 4 is a time chart showing a schematic relationship between a required control amount Xa, a first maximum control amount Xa1max, and a second control amount Xa2. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0016] In each embodiment described below, elements common to each drawing are given the same reference numerals, and duplicated explanations are omitted or simplified. Furthermore, when the number, quantity, amount, range, etc. of each element is mentioned in the embodiments described below, the technical idea of ​​the present disclosure is not limited to the mentioned number, unless otherwise specified or clearly specified in principle.

[0017] 1. First embodiment 1-1.Vehicle configuration examples FIG. 1 is a diagram showing a schematic example of a configuration of a vehicle 1 according to a first embodiment. The vehicle 1 includes wheels 2 and suspensions 3. The wheels 2 include a left front wheel 2FL, a right front wheel 2FR, a left rear wheel 2RL, and a right rear wheel 2RR. Suspensions 3FL, 3FR, 3RL, and 3RR are provided for the left front wheel 2FL, the right front wheel 2FR, the left rear wheel 2RL, and the right rear wheel 2RR, respectively. In the following description, unless there is a particular need to distinguish between them, each wheel will be referred to as a wheel 2, and each suspension will be referred to as a suspension 3.

[0018] FIG. 2 is a conceptual diagram showing a configuration example of the suspension 3 according to the first embodiment. The suspension 3 is provided to connect between the unsprung structure 4 and the sprung structure 5 of the vehicle 1. The unsprung structure 4 includes the wheel 2. The suspension 3 includes a spring 3S, a damper (shock absorber) 3D, and an actuator 3A. The spring 3S, the damper 3D, and the actuator 3A are provided in parallel between the unsprung structure 4 and the sprung structure 5. The actuator 3A controls the stroke ST of the suspension 3. The spring 3S has a spring constant K. The damper 3D has a damping coefficient C. The actuator 3A applies a control force Fc in the vertical direction between the unsprung structure 4 and the sprung structure 5.

[0019] More specifically, the actuator 3A is, for example, an electric or hydraulic active actuator (an actuator constituting a so-called fully active suspension). Alternatively, the actuator 3A may be, for example, an actuator that varies the damping force generated by the damper 3D, or an actuator of an active stabilizer device. Furthermore, the "one or more actuators" according to the present disclosure may be any actuator that controls the stroke ST of the suspension 3, and may be, for example, an air spring (for example, air spring 7A shown in FIG. 8) provided in place of a coil spring instead of the actuator 3A.

[0020] 1-2.Vehicle control system 1-2-1. Configuration example 3 is a block diagram showing an example of the configuration of a vehicle control system 10 according to embodiment 1. The vehicle control system 10 is mounted on a vehicle 1 and controls the vehicle 1. The vehicle control system 10 includes a vehicle state sensor 20, a recognition sensor 30, a position sensor 40, a communication device 50, a driving device 60, and an electronic control unit (ECU) 70.

[0021] The vehicle state sensor 20 detects the state of the vehicle 1. The vehicle state sensor 20 includes, for example, a vehicle speed sensor (wheel speed sensor) 21 that detects the vehicle speed of the vehicle 1, a lateral acceleration sensor 22 that detects the lateral acceleration LA of the vehicle 1, and a longitudinal acceleration sensor 23 that detects the longitudinal acceleration FA of the vehicle 1. The vehicle state sensor 20 may also include a sprung acceleration sensor. In addition, the vehicle state sensor 20 includes a yaw rate sensor, a steering angle sensor, an accelerator position sensor, a brake position sensor, and the like.

[0022] The recognition sensor 30 recognizes (detects) the surrounding situation of the vehicle 1. Examples of the recognition sensor include a camera, a LIDAR (Laser Imaging Detection and Ranging), and a radar.

[0023] The position sensor 40 detects the position and orientation of the vehicle 1. For example, the position sensor 40 includes a Global Navigation Satellite System (GNSS) receiver.

[0024] The communication device 50 communicates with the outside of the vehicle 1 .

[0025] The traveling device 60 includes a steering device 61, a driving device 62, a braking device 63, and a suspension 3 (see FIG. 2). The steering device 61 steers the wheels 2. For example, the steering device 61 includes an electric power steering (EPS) device. The driving device 62 is a power source that generates a driving force. Examples of the driving device 62 include an engine, an electric motor, and an in-wheel motor. The braking device 63 generates a braking force.

[0026] The ECU 70 is a computer that controls the vehicle 1. The ECU 70 includes one or more processors 71 (hereinafter simply referred to as processor 71) and one or more storage devices 72 (hereinafter simply referred to as storage devices 72). The processor 71 executes various processes. For example, the processor 71 includes a CPU (Central Processing Unit). The storage device 72 stores various information required for processing by the processor 71. Examples of the storage device 72 include a volatile memory, a non-volatile memory, an HDD (Hard Disk Drive), an SSD (Solid State Drive), and the like. There may be multiple ECUs 70.

[0027] The vehicle control program 80 is a computer program for controlling the vehicle 1, and is executed by the processor 71. The vehicle control program 80 is stored in the storage device 72. Alternatively, the vehicle control program 80 may be recorded in a computer-readable recording medium. The processor 71 executes the vehicle control program 80 to realize the functions of the ECU 70.

[0028] 1-2-2. Driving environment information 4 is a block diagram showing an example of driving environment information 90 indicating the driving environment of the vehicle 1. The driving environment information 90 is stored in the storage device 72. The driving environment information 90 includes map information 91, vehicle state information 92, surrounding situation information 93, and position information 94.

[0029] The map information 91 includes a general navigation map. The map information 91 may indicate lane layouts, road shapes, and the like. The map information 91 may include position information of white lines, traffic lights, signs, landmarks, and the like. The map information 91 is obtained from a map database. The map database may be mounted on the vehicle 1, or may be stored in an external management server. In the latter case, the ECU 70 communicates with the management server to obtain the necessary map information 91.

[0030] The vehicle state information 92 is information indicating a state of the vehicle 1. The ECU 70 acquires the vehicle state information 92 from the vehicle state sensor 20. For example, the vehicle state information 92 includes a vehicle speed, a sprung acceleration, a stroke ST, a lateral acceleration LA, a longitudinal acceleration FA, a yaw rate, a steering angle, etc. The vehicle speed may be calculated from the vehicle position detected by the position sensor 40.

[0031] The surrounding situation information 93 is information indicating the situation around the vehicle 1. The ECU 70 recognizes the situation around the vehicle 1 using the recognition sensor 30, and acquires the surrounding situation information 93. For example, the surrounding situation information 93 includes image information captured by a camera. As another example, the surrounding situation information 93 includes point cloud information obtained by a LIDAR.

[0032] The position information 94 is information indicating the position and orientation (vehicle traveling direction) of the vehicle 1. The ECU 70 acquires the position information 94 from a measurement result by a position sensor 40 such as a GNSS receiver. As another example, the ECU 70 may acquire the position information 94 by dead reckoning.

[0033] 1-2-3.Vehicle control The ECU 70 executes vehicle driving control for controlling the driving of the vehicle 1. The vehicle driving control includes steering control, drive control, and braking control. The ECU 70 executes vehicle driving control by controlling the driving device 60 (the steering device 61, the drive device 62, and the braking device 63). The ECU 70 executes automatic driving control for automatically performing at least one of steering, acceleration, and deceleration of the vehicle 1 based on the driving environment information 90.

[0034] Furthermore, the ECU 70 switches the driving mode between a manual driving mode in which the driver drives the vehicle 1 and an automatic driving mode in which automatic driving control is executed. More specifically, the manual driving mode here refers to a driving mode in which the driver performs all operations of steering, acceleration, and deceleration. Examples of automatic driving control (driving assistance control) in which the vehicle 1 automatically performs some of the steering, acceleration, and deceleration include adaptive cruise control (ACC), lane keeping control, and the like.

[0035] Furthermore, the ECU 70 controls the suspension 3. Specifically, the control of the suspension 3 includes "posture control" described below. The ECU 70 controls the actuator 3A to control the posture of the vehicle 1. In the posture control, the actuator 3A generates a control force Fc in the vertical direction between the unsprung structure 4 and the sprung structure 5 (see FIG. 2).

[0036] 1-3. Vehicle attitude control The attitude control here refers to at least one of roll control during turning accompanying steering of the vehicle 1 and pitch control during acceleration / deceleration of the vehicle 1. In this embodiment, both roll control and pitch control are executed as the attitude control.

[0037] The roll control here refers to control for generating a reverse roll moment by controlling the control force Fc of the actuator 3A so as to cancel out the roll that occurs when the vehicle 1 turns due to steering. More specifically, "canceling the roll" refers to suppressing the roll that occurs compared to the case without roll control, or generating a roll in the opposite direction to the roll that occurs. Similarly, the pitch control here refers to control for generating a reverse pitch moment by controlling the control force Fc of the actuator 3A so as to cancel out the pitch that occurs when the vehicle 1 accelerates or decelerates. More specifically, "canceling the pitch" refers to suppressing the pitch that occurs compared to the case without pitch control, or generating a pitch in the opposite direction to the pitch that occurs.

[0038] In this embodiment, in order to improve comfort in the autonomous driving mode while taking into account the drive feel in the manual driving mode, the ECU 70 executes the following "calculation process" and "command process." That is, the ECU 70 executes a calculation process to calculate a required control amount for roll control and pitch control of the vehicle 1. Then, the ECU 70 executes a command process to command the actuator 3A with the calculated required control amount. In the calculation process, the ECU 70 makes the control gain included in the required control amount larger in the autonomous driving mode than in the manual driving mode.

[0039] Fig. 5 is a flowchart showing a process related to attitude control according to embodiment 1. The process of this flowchart is repeatedly executed at predetermined time steps Δt (see Fig. 10) while the vehicle 1 is traveling. In Fig. 5, the processes of steps S100 to S106 correspond to an example of the above-mentioned "calculation process", and the process of step S108 corresponds to an example of the above-mentioned "command process".

[0040] <Step S100> 5, in step S100, the ECU 70 determines whether the vehicle 1 is in the autonomous driving mode. If the vehicle 1 is not in the autonomous driving mode, that is, if the vehicle 1 is in the manual driving mode, the process proceeds to step S102. On the other hand, if the vehicle 1 is in the autonomous driving mode, the process proceeds to step S104.

[0041] <Step S102> In step S102, the ECU 70 calculates a required control amount Xm for attitude control during the manual driving mode. When both roll control and pitch control are performed, the required control amount Xm is the sum of a required control amount Xmr for roll control and a required control amount Xmp for pitch control. More specifically, the required control amount Xmr corresponds to a required value of the control force Fc required for roll control. The required control amount Xp corresponds to a required value of the control force Fc required for pitch control.

[0042] In step S102, the ECU 70 calculates the required control amounts Xmr and Xmp for each wheel 2. Then, the ECU 70 calculates the sum of the calculated required control amounts Xmr and Xmp as the required control amount Xm for each wheel 2.

[0043] In addition, for each wheel 2, the control force Fc, which is the suspension generated force, is positive when it acts to lift the sprung structure 5 upward. Accordingly, the required control amount Xm (Xmr and Xmp) is also positive when it acts to lift the sprung structure 5 upward. Therefore, the required control amount Xmr is positive for the wheel 2 on the outside of the turn and negative for the wheel 2 on the inside of the turn. Similarly, the required control amount Xmp is negative for the front wheels 2FL and 2FR and positive for the rear wheels 2RL and 2RR during acceleration, and conversely, is positive for the front wheels 2FL and 2FR and negative for the rear wheels 2RL and 2RR during deceleration. The same applies to the required control amount Xa (Xar and Xap) described below.

[0044] 6(A) and 6(B) are diagrams for explaining an example of a calculation method of the required control amount Xr for roll control and the required control amount Xp for pitch control, respectively. Here, the required control amounts Xmr and Xmp for the manual driving mode are explained first. The required control amounts Xar and Xap for the automatic driving mode will be described later together with the process of step S106.

[0045] The required control amounts Xmr and Xmp include control gains Gmr and Gmp, respectively. As an example, the required control amounts Xmr and Xmp are expressed by the following equations (1) and (2), respectively. Xmr = LA × Gmr (1) Xmp = FA × Gmp (2)

[0046] As shown in equation (1), the required control amount Xmr is given by the product of the lateral acceleration LA and the control gain Gmr. As shown in equation (2), the required control amount Xmp is given by the product of the longitudinal acceleration FA and the control gain Gmp. Note that the control gain Gmr for roll control and the control gain Gmp for pitch control may be the same or different.

[0047] In step S102, the ECU 70 calculates the required control amount Xmr at the next sample time (k+1). The required control amount Xmr is calculated by multiplying the lateral acceleration LA acquired at the current sample time (k) by a control gain Gmr (proportionality coefficient). Therefore, as shown in FIG. 6(A), as the absolute value of the lateral acceleration LA increases, the absolute value of the required control amount Xmr also increases. The control gain Gmr corresponds to the gradient of the straight line shown in FIG. 6(A) and is, for example, a fixed value determined in advance. However, the control gain Gmr may be variable according to a parameter related to posture control. The lateral acceleration LA can be acquired, for example, by using the lateral acceleration sensor 22. The lateral acceleration LA may also be estimated based on information such as the vehicle speed and steering angle.

[0048] Furthermore, the ECU 70 calculates the required control amount Xmp at the next sample time (k+1). Similarly, the required control amount Xmp is calculated by multiplying the longitudinal acceleration FA acquired at the current sample time (k) by the control gain Gmp (proportional coefficient). Therefore, as shown in FIG. 6B, as the absolute value of the longitudinal acceleration FA increases, the absolute value of the required control amount Xmp also increases. The control gain Gmp corresponds to the gradient of the straight line shown in FIG. 6B, and is, for example, a fixed value determined in advance. However, the control gain Gmp may be variable according to a parameter related to posture control. The longitudinal acceleration FA can be acquired, for example, by using the longitudinal acceleration sensor 23. Furthermore, the longitudinal acceleration FA may be estimated, for example, based on required information of the vehicle longitudinal force (for example, required engine torque or required braking force).

[0049] In addition, as long as the required control amounts Xmr and Xmp include the control gains Gmr and Gmp, respectively, the calculation method of the required control amounts Xmr and Xmp is not particularly limited. That is, for example, the required control amounts Xmr and Xmp may be calculated based on virtual roll and pitch dynamic characteristics (e.g., spring constants and damping coefficients), respectively. The required control amounts Xmr and Xmp may also be calculated based on other control laws or control theories. In addition, the required control amounts Xmr and Xmp do not need to be based on the lateral acceleration LA and the longitudinal acceleration FA, respectively.

[0050] <Step S104> In step S104, the ECU 70 acquires future operation information that has been acquired separately for path planning in the automatic driving control performed in the vehicle control system 10. This future operation information is future information related to at least one of steering and acceleration / deceleration of the vehicle 1. Specifically, the future operation information is, for example, information on operations related to future steering and acceleration / deceleration of the vehicle 1, or information corresponding to future steering and acceleration / deceleration (for example, information on future lateral acceleration LA and longitudinal acceleration FA). In addition, the future operation information is time-, distance-, or position-based information. Note that, when only operation information related to steering and acceleration / deceleration is obtained as the future operation information, the lateral acceleration LA and longitudinal acceleration FA may be estimated from the operation information related to steering and acceleration / deceleration.

[0051] <Step S106> In step S106 following step S104, the ECU 70 calculates a required control amount Xa for the attitude control in the autonomous driving mode. When both the roll control and the pitch control are performed, the required control amount Xa is the sum of the required control amount Xar for the roll control and the required control amount Xap for the pitch control.

[0052] In step S106, the ECU 70 calculates the required control amounts Xar and Xap for each wheel 2. Then, the ECU 70 calculates, for each wheel 2, the sum of the calculated required control amounts Xar and Xap as the required control amount Xa.

[0053] The required controlled variables Xar and Xap include control gains Gar and Gap, respectively. As an example, the required controlled variables Xar and Xap are expressed by the following equations (3) and (4), respectively. Xar = LA × Gar (3) Xap = FA × Gap (4)

[0054] As shown in equation (3), the required control amount Xar is given by the product of the lateral acceleration LA and the control gain Gar. As shown in equation (4), the required control amount Xap is given by the product of the longitudinal acceleration FA and the control gain Gap. Note that the control gain Gar for roll control and the control gain Gap for pitch control may be the same or different.

[0055] In step S106, the ECU 70 calculates a required control amount Xar at the next sample time (k+1). The required control amount Xar is calculated, for example, by multiplying the future operation information acquired in step S104 (here, the lateral acceleration LA at the next sample time (k+1)) by a control gain Gar.

[0056] Here, the control gain Gar for roll control in the autonomous driving mode is, for example, a fixed value determined in advance and is determined to be larger than the control gain Gmr for roll control in the manual driving mode. Therefore, as shown in Fig. 6(A), as the absolute value of the lateral acceleration LA increases, the absolute value of the required control amount Xar increases at a steeper slope than the absolute value of the required control amount Xmr. Note that, as long as the condition that the control gain Gar is larger than the control gain Gmr is satisfied, the control gain Gar may be variable according to a parameter related to posture control.

[0057] In step S106, the ECU 70 calculates a required control amount Xap at the next sample time (k+1). The required control amount Xap is calculated, for example, by multiplying the future operation information acquired in step S104 (here, the longitudinal acceleration FA at the next sample time (k+1)) by a control gain Gap.

[0058] Here, the control gain Gap for pitch control in the automatic driving mode is, for example, a fixed value determined in advance and is determined to be larger than the control gain Gmp for pitch control in the manual driving mode. Therefore, as shown in Fig. 6(B), as the absolute value of the longitudinal acceleration FA increases, the absolute value of the required control amount Xap increases at a larger slope than the absolute value of the required control amount Xmp. Note that, as long as the condition that the control gain Gap is larger than the control gain Gmp is satisfied, the control gain Gap may be variable according to a parameter related to posture control.

[0059] In addition, the required control amount Xa (Xar and Xap) may be calculated taking into account the dynamic characteristics of the actuator 3A. Specifically, the required control amount Xa may be calculated taking into account, for example, one or both of the first-order delay characteristics and the dead time characteristics of the actuator 3A. Also, the required control amount Xa may be calculated taking into account, for example, a delay in communication between the ECU 70 and the actuator 3A (for example, a known dead time). The dynamic characteristics and the communication delay of the actuator 3A may be acquired in advance and stored in the storage device 72. Also, at least one of the dynamic characteristics and the communication delay of the actuator 3A may be taken into account when issuing the required control amount Xa to the actuator 3A in step S108 described later. Specifically, the command to the actuator 3A may be advanced by, for example, the time constant of the first-order delay, or may be advanced by one or both of the dead times related to the actuator 3A and the communication.

[0060] (Example of calculation of control gain Gar / Gap with roll rate / pitch rate limit) Furthermore, the calculation of the required control amount Xa (Xar and Xap) in step S106 may be performed, for example, in accordance with the following process on the condition that the control gain Gar / Gap is greater than the control gain Gmr / Gmp for the manual driving mode.

[0061] If the reverse roll moment / reverse pitch moment becomes excessive as a result of increasing the control gain Gar / Gap from the viewpoint of improving passenger comfort, the roll rate / pitch rate may become excessive accordingly, which may in turn impair comfort. On the other hand, in the autonomous driving mode, it is possible to know in advance what kind of steering / acceleration / deceleration will be performed by using future operation information (see step S104) acquired in the autonomous driving control.

[0062] Therefore, the ECU 70 may set an upper limit on the roll rate based on future operation information (for example, information on future steering and vehicle speed).The ECU 70 may then determine (calculate) the control gain Gar so that the actuator 3A generates a maximum control force Fc within a range in which the roll rate does not exceed the upper limit. The upper limit on the roll rate may be, for example, a fixed value set in advance, or may be variable according to a parameter related to roll control.

[0063] Furthermore, the ECU 70 may set an upper limit to the pitch rate based on future operation information (for example, information on future acceleration and deceleration). Then, the ECU 70 may determine (calculate) the control gain Gap so that the actuator 3A generates a maximum control force Fc within a range in which the pitch rate does not exceed the upper limit. The upper limit of the pitch rate may be, for example, a fixed value set in advance, or may be variable according to a parameter related to pitch control.

[0064] <Step S108> In step S108, the ECU 70 issues a command to the actuator 3A of the required control amount Xm calculated in step S102 or the required control amount Xa calculated in step S106. As a result, the actuator 3A is controlled to generate a control force Fc according to the commanded required control amount Xm or Xa.

[0065] 1-4.Effects

[0066] In the manual driving mode, the roll control needs to take into consideration the driver's drive feel. For this reason, in order to enhance the effect of the roll control and improve comfort, it is difficult (in other words, it is not preferable) to generate a control force Fc so as to sufficiently increase the reverse roll moment for canceling the generated roll. On the other hand, in the automatic driving mode, it is not necessary to take into consideration the drive feel (in the example of the automatic driving mode in which only a part of steering, acceleration, and deceleration is automated, it is not necessary to take into consideration the driver's drive feel related to the part that is automated). Even so, if the control gain Gar in the automatic driving mode is the same as the control gain Gmr in the manual driving mode, the effect of the roll control cannot be sufficiently enhanced in the automatic driving mode. Conversely, if the control gains Gar and Gmr are both increased by the same value in order to prioritize the automatic driving mode over the manual driving mode, the drive feel in the manual driving mode will deteriorate. The same applies to the control gains Gap and Gmp in the pitch control.

[0067] In contrast, according to the first embodiment, the control gain Gar used in the automatic driving mode is larger than the control gain Gmr used in the manual driving mode. Similarly, the control gain Gap is larger than the control gain Gmp. This makes it possible to realize posture control (roll control and pitch control) that can improve comfort in the automatic driving mode while taking into account the drive feel in the manual driving mode. More specifically, in the manual driving mode, the control gains Gmr and Gmp can be appropriately suppressed to be small so as not to be excessive, thereby suppressing a deterioration in the drive feel. On the other hand, in the automatic driving mode, the control gains Gar and Gap can be relatively large, so that the reverse roll moment / reverse pitch moment generated under the same lateral acceleration LA / longitudinal acceleration FA conditions can be made larger than in the manual driving mode. As a result, the effect of the posture control is enhanced, improving comfort.

[0068] In the method of using the same control gain in the manual driving mode and the automatic driving mode, the reason why it is difficult to realize posture control that can improve comfort in the automatic driving mode while considering the drive feel in the manual driving mode will be supplemented. That is, first, the control force Fc that the actuator 3A can generate is limited, and the stroke ST of the suspension 3 is also limited. Therefore, there is a limit to the amount of change in the roll angle / pitch angle in the opposite direction to cancel the roll / pitch that occurs. In addition, unlike in the automatic driving mode, in the manual driving mode, it is necessary to assume that the driver generates a high lateral acceleration LA / longitudinal acceleration FA (e.g., 1.0 G). Therefore, if the control gain is increased so that the roll / pitch caused by the low acceleration LA / FA (e.g., 0.1 G or 0.2 G) can be sufficiently canceled when the acceleration LA / FA acts, a satisfactory control force Fc cannot be generated when the high acceleration LA / FA (e.g., 1.0 G) acts. In addition, the control force Fc is insufficient in the high acceleration LA / FA region, and as a result, the characteristics of the roll angle / pitch angle with respect to the acceleration LA / FA become nonlinear, which leads to a deterioration of the drive feel. In view of this, if one were to assume the occurrence of a high acceleration LA / FA (e.g., 1.0 G) and attempt to make the characteristics of the roll angle / pitch angle with respect to the acceleration LA / FA a linear relationship from the low acceleration range to the high acceleration range, it would become difficult to increase the control gain by placing emphasis on the low acceleration range.

[0069] In addition, increasing the reverse roll moment / reverse pitch moment may lead to an increase in the roll rate / pitch rate. As a result, if the roll rate / pitch rate becomes excessive, the passengers may feel uncomfortable. In contrast, according to the first embodiment, the upper limit of the roll rate / pitch rate is set based on future operation information, and the control gain Gar / Gap is determined so that the actuator 3A generates the maximum control force Fc within a range in which the roll rate / pitch rate does not exceed the upper limit. As a result, in the autonomous driving mode, it is possible to perform attitude control using a large reverse roll moment / reverse pitch moment, while preventing the roll rate / pitch rate from becoming excessive, compared to the example in which the control gain Gar / Gap is the same as the control gain Gmr / Gmp in the manual driving mode. As a result, the comfort of the passengers during steering / acceleration / deceleration during the autonomous driving mode is improved.

[0070] 1-5. Restrictions on autonomous driving according to suspension performance In the above-described first embodiment, an example has been described in which the control force Fc of the actuator 3A of the suspension 3 is limited based on the upper limit of the roll rate / pitch rate. Instead of such an example, in an autonomous driving mode in which a control gain Gar / Gap larger than the control gain Gmr / Gmp for the manual driving mode is used, a restriction may be imposed on autonomous driving according to the performance of the suspension 3.

[0071] (Example 1) Specifically, a constraint may be imposed on the automatic driving control based on at least one of the maximum reverse roll angle θrmax and the maximum roll rate RRmax.

[0072] The maximum reverse roll angle θrmax referred to here is the maximum value of the reverse roll angle θr that can be controlled to cancel the roll that occurs when the lateral acceleration LA occurs in the vehicle 1 due to steering, and is a value determined by the structure and performance of the suspension 3. In other words, the suspension 3 cannot generate a reverse roll angle θr that exceeds this maximum reverse roll angle θrmax. For this reason, the maximum lateral acceleration LAmax, which is the maximum value of the lateral acceleration LA that can generate a reverse roll moment to cancel the roll, is determined according to the maximum reverse roll angle θrmax. Therefore, the automatic driving control (for example, the control of steering and vehicle speed) may be limited so that the lateral acceleration LA that exceeds this maximum lateral acceleration LAmax does not occur.

[0073] The maximum roll rate RRmax here is the maximum value of the roll rate that the actuator 3A can generate to cancel the roll. When the maximum roll rate RRmax is determined, the maximum lateral jerk LJmax, which is the time differential value of the lateral acceleration LA that generates a roll rate equal to the maximum roll rate RRmax, is determined. Therefore, automatic driving control (for example, steering control) may be limited so that a lateral jerk LJ exceeding this maximum lateral jerk LJmax does not occur.

[0074] Also, based on the same idea as in the concrete example 1 of the roll control described above, in the pitch control, a restriction may be set on the automatic driving control based on at least one of the maximum reverse pitch angle θpmax and the maximum pitch rate PRmax. Specifically, the automatic driving control (for example, the acceleration and deceleration control) may be limited so that the longitudinal acceleration FA does not exceed the maximum longitudinal acceleration FAmax. Also, the automatic driving control (for example, the acceleration and deceleration control) may be limited so that the longitudinal jerk FJ does not exceed the maximum longitudinal jerk FJmax.

[0075] (Example 2) In an example in which ride comfort control is performed in combination with attitude control as suspension control using actuator 3A, the above-mentioned specific example 1 may be performed as follows. Here, roll control is taken as an example for explanation, but the same applies to pitch control. Note that the ride comfort control referred to here is vibration suppression control for improving ride comfort by suppressing vertical vibration of the sprung structure 5 caused by input from the road surface. The ride comfort control is, for example, preview control based on road surface information ahead of the vehicle, or feedback control for reducing vibration of the sprung structure 5 using at least one of sprung displacement, sprung velocity, and sprung acceleration.

[0076] The output (control force Fc) of the actuator 3A is limited. Therefore, when the ride comfort control is executed together with the posture control, a part of the output of the actuator 3A is used for the ride comfort control. Therefore, compared with the example without the ride comfort control, the spare force of the actuator 3A available for the posture control is reduced. This leads to a reduction in the maximum lateral acceleration LAmax (also the maximum longitudinal acceleration FAmax) and the maximum lateral jerk LJmax (also the maximum longitudinal jerk FJmax) in the above-mentioned specific example 1.

[0077] Therefore, at least one of the maximum lateral acceleration LAmax / maximum longitudinal acceleration FAmax and the maximum lateral jerk LJmax / maximum longitudinal jerk FJmax may be changed depending on the usage status of the ride comfort control (in other words, depending on the proportion of the output of actuator 3A used by the ride comfort control).

[0078] Specifically, when the ratio of the output of actuator 3A used by the ride comfort control is large (for example, when traveling on a rough road surface with large unevenness), at least one of maximum lateral acceleration LAmax / maximum longitudinal acceleration FAmax and maximum lateral jerk LJmax / maximum longitudinal jerk FJmax may be modified to be lower than when traveling on a flat road surface. As a result, if the traveling trajectory of vehicle 1 is the same, the automatic driving control is executed to reduce the vehicle speed.

[0079] 2. Second embodiment The second embodiment differs from the first embodiment described above in the points described below.

[0080] As already described, in the autonomous driving mode, it is possible to know in advance what kind of steering / acceleration / deceleration will be performed by using future operation information (see step S104) acquired in the autonomous driving control. However, there is a possibility that high-frequency noise may be superimposed on such future operation information (for example, time-based information (time-series data)).

[0081] Therefore, in the second embodiment, in the calculation process in the autonomous driving mode, the ECU 70 performs low-pass filter (LPF) processing on the future operation information. Then, the ECU 70 calculates the required control amount Xa (Xar and Xap) based on the future operation information after the LPF processing.

[0082] Furthermore, in the command process, when the above-mentioned LPF process is performed, the ECU 70 advances the timing of commanding the actuator 3A of the required control amount Xa (Xar and Xap) compared to when the LPF process is not performed.

[0083] Fig. 7 is a flowchart showing a process related to attitude control according to embodiment 2. In Fig. 7, the process proceeds to step S200 after step S104. The process of step S200, together with the process of step S202, is included in the "calculation process".

[0084] <Step S200> In step S200, the ECU 70 performs LPF processing on the future operation information acquired in step S104. In an example in which the required control amounts Xar and Xap are calculated using the formulas (3) and (4), an example of the future operation information to be subjected to the LPF processing is each of time series data of the lateral acceleration LA and the longitudinal acceleration FA.

[0085] The LPF process is a filter process for removing (attenuating) high-frequency noise that may be superimposed on future operation information as described above. In addition, in an example in which LPF process (for convenience, referred to as "LPF process A") is performed on information that is the basis for calculating the required control amounts Xmr and Xmp for the manual driving mode (in an example in which formulas (1) and (2) are used, the lateral acceleration LA and the longitudinal acceleration FA), the LPF process of this step S200 may be performed with a higher intensity than the LPF process A. Specifically, for example, the LPF process of this step S200 may be performed with a lower cutoff frequency than the LPF process A, or may be performed as a low-pass filter of a higher order than the LPF process A.

[0086] <Step S202> After step S200, the ECU 70 executes the process of step S202. The process of step S202 differs from step S106 (see FIG. 5) in that the future operation information on which the required control amount Xa (Xar and Xap) is calculated is information after the LPF process.

[0087] <Step S204> 7, after step S202 or S102, the process proceeds to step S204. The process of step S204 is the same as step S108 (see FIG. 5), except that if it is performed after step S202, it includes the following process:

[0088] That is, the process (command process) of step S204 includes a process of advancing the timing of commanding the actuator 3A of the required control amount Xa (Xar and Xap) compared to the case where the LPF process of step S200 is not performed. This process is for compensating for the phase delay of the future operation information caused by the execution of the LPF process. Specifically, the ECU 70 advances the command timing by, for example, the time constant of the LPF process.

[0089] As already explained, in the automatic driving mode, unlike the manual driving mode, it is possible to know in advance what kind of steering / acceleration / deceleration will be performed by using future operation information acquired in the automatic driving control. Therefore, unlike the manual driving mode, it is difficult for sudden steering or acceleration / deceleration operations to be performed and delay in the operation of the actuator 3A to occur. Therefore, it becomes possible to acquire future operation information in which high-frequency noise has been satisfactorily removed (attenuated) using a high-intensity LPF process without the adverse effect of such operation delay, for calculation of the required control amount Xa (Xar and Xap). In addition, the phase delay of the future operation information caused by the execution of the LPF can be compensated for by advancing the command timing of the required control amount Xa (Xar and Xap) to the actuator 3A.

[0090] 3. Third embodiment The third embodiment differs from the first embodiment in the following respects: The third embodiment may be combined with the second embodiment.

[0091] 3-1.Suspension configuration examples Fig. 8 is a diagram showing an example of the configuration of a suspension 7 provided on a vehicle 6 according to a third embodiment. The suspension 7 includes a damper 3D and an actuator 3A similar to those of the suspension 3 shown in Fig. 2, and an air spring 7A which is another actuator. The suspension arm 8 connects the wheel 2 and the vehicle body 9. The air spring 7A, together with the damper 3D, is interposed between the suspension arm 8 and the vehicle body 9.

[0092] The air spring 7A includes an air pump installed on the vehicle body 9. The air pump is, for example, electric. The pressure of the compressed air supplied to the inside of the air spring 7A is controlled by the ECU 70. According to the air spring 7A, a control force Fc1 according to the air pressure inside the air spring 7A can be generated as one of the control forces Fc acting between the sprung structure 5 and the unsprung structure 4. Then, by adjusting this air pressure to control the control force Fc1, the stroke ST of the suspension 7 can be adjusted. By including the air spring 7A, the suspension 7 constitutes an air suspension. The air spring 7A corresponds to an example of a "first actuator" according to the present disclosure, and is hereinafter also referred to as a "first actuator 7A".

[0093] In the third embodiment, the control force Fc generated by the actuator (active actuator) 3A is referred to as "Fc2" to distinguish it from the control force Fc1 of the first actuator 7A. The actuator 3A corresponds to an example of the "second actuator" according to the present disclosure, and hereinafter is also referred to as the "second actuator 3A."

[0094] 3-2. Vehicle attitude control The above-mentioned first actuator (air spring) 7A functions as a suspension spring that absorbs shocks from the road surface, and can adjust the vehicle height of the vehicle 6 by controlling the stroke ST. Therefore, the first actuator 7A corresponds to an example of a so-called "vehicle height adjustment device." Vehicle height adjustment using such a vehicle height adjustment device is performed for purposes such as lowering the vehicle height to make it easier for passengers to get on and off the vehicle, or lowering the vehicle height to reduce air resistance when the vehicle speed increases.

[0095] On the other hand, the second actuator (active actuator) 3A can perform full active control. Specifically, as described above, the second actuator 3A can be used for the attitude control (roll control and pitch control) of the vehicle 6. The second actuator 3A can also be used for the ride comfort control described above.

[0096] The responsiveness of the actuators 7A and 3A, both of which can adjust the stroke ST, differs depending on their basic intended use. Specifically, the intended use of the first actuator 7A as a vehicle height adjustment device is as described above. For this reason, the first actuator 3A is not required to have high responsiveness in adjusting the stroke ST. On the other hand, the intended use of the second actuator 3A is control requiring high responsiveness, such as the above-mentioned attitude control and ride comfort control, and therefore the second actuator 3A is configured to satisfy high responsiveness.

[0097] Therefore, the responsiveness of the second actuator 3A is higher than that of the first actuator 7A. On the other hand, the second actuator 3A, which is an actuator for full active control, basically continues to consume energy during the execution of posture control, and has an aspect of poor energy efficiency. For this reason, if posture control (control of roll angle and pitch angle) is performed using only the second actuator 3A, it is easy to ensure high control responsiveness, but energy consumption increases. Here, the first actuator 7A as a vehicle height adjustment device can also be used for posture control because the stroke ST can be adjusted. However, it is difficult to always satisfy the responsiveness required for posture control by using only the first actuator 7A.

[0098] Therefore, in the third embodiment, the first and second actuators 7A and 3A are used in combination for posture control. Specifically, in command processing in the autonomous driving mode, when the first maximum control amount Xa1max, which is the maximum value of the first control amount Xa1 that the first actuator 7A can output, is insufficient in the control amount for the required control amount Xa, the ECU 70 commands the first actuator 7A to have the first maximum control amount Xa1max, and also commands the second actuator 3A to have the second control amount Xa2 to compensate for the insufficiency.

[0099] Fig. 9 is a flowchart showing a process related to attitude control according to embodiment 3. In Fig. 9, the process proceeds to step S300 after calculation of the required control amount Xa in step S106. Note that the "command process" in the example shown in Fig. 9 includes steps S300, S302, and S306 as well as the processes of steps S304, S308, and S310.

[0100] <Step S300> In step S300, the ECU 70 calculates a first maximum control amount Xa1max that can be output by the first actuator (air spring) 7A. More specifically, the first maximum control amount Xa1max corresponds to the maximum first control amount Xa1 that can be output by the first actuator 7A, including the time when the first control amount Xa1 changes over time. In step S300, the ECU 70 calculates the first maximum control amount Xa1max that can be output at the next sample time (k+1).

[0101] Here, the maximum change rate V1max and maximum value Fc1max (see FIG. 10) of the control force Fc1 that can be output by the first actuator 7A are basically determined by the specifications of the first actuator 7A. Therefore, the maximum change rate V1max and maximum value Fc1max can be known in advance. The storage device 72 of the ECU 70 stores information on the basic operating characteristics of the first actuator 7A, such as the maximum change rate V1max and maximum value Fc1max. More specifically, the maximum change rate V1max corresponds to the maximum change amount ΔFc1max (see FIG. 10) per unit time (time step Δt).

[0102] FIG. 10 is a time chart that shows a schematic relationship between the required control amount Xa, the first maximum control amount Xa1max, and the second control amount Xa2. FIG. 10 shows an example of turning caused by steering the vehicle 6, but for the sake of simplicity, it is assumed that there is no change in the longitudinal acceleration FA caused by acceleration or deceleration of the vehicle 6. That is, in FIG. 10, the required control amount Xap is treated as zero. Therefore, the required control amount Xar is equal to the required control amount Xa. The relationship shown in FIG. 10 is for the wheel 2 that is on the outside of the turn during turning. In the relationship for the wheel 2 that is on the inside of the turn during turning, the signs of the required control amount Xa and the first maximum control amount Xa1max are opposite to those in the relationship shown in FIG. 10.

[0103] In addition, when the longitudinal acceleration FA changes during turning, the waveform of the required control amount Xa shown in Fig. 10 also changes due to the change in the required control amount Xap. However, the calculation of the first maximum control amount Xa1max and the second control amount Xa2 described below can be performed in the same manner as the example shown in Fig. 10 even when the longitudinal acceleration FA changes regardless of whether or not the vehicle is turning.

[0104] In the example shown in Fig. 10, with the start of steering at the sample time (k = 0), the lateral acceleration LA increases over time, and the required control amount Xa increases accordingly. In this example, the vehicle then enters a steady circular turning state where the vehicle speed and lateral acceleration LA are constant, and the required control amount Xa remains constant over time. More specifically, Fig. 10 shows the required control amount Xa (solid line and dashed line) during two types of turning that differ in the lateral acceleration LA that occurs during turning.

[0105] The first maximum control amount Xa1max of the first actuator 7A at each sample time k can be calculated based on, for example, the maximum change rate V1max and the maximum value Fc1max described above. Specifically, as shown in FIG. 10, first, the first maximum control amount Xa1max at the sample time (k=0) is zero. The first maximum control amount Xa1max at the next sample time (k=1) is calculated as the maximum change amount ΔFc1max, which is the product of the maximum change rate V1max stored in the storage device 72 and the time step Δt. The first maximum control amount Xa1max at each sample time k during the period from the next sample time (k=2) onwards until the first maximum control amount Xa1max reaches the maximum value Fc1max, is calculated by adding the maximum change amount ΔFc1max to the previous value. The first maximum control amount Xa1max after the first maximum control amount Xa1max reaches the maximum value Fc1max is calculated as the maximum value Fc1max. In addition, when the first maximum control amount Xa1max calculated in this manner is compared with the required control amount Xa shown by the solid line, the time waveform of the first maximum control amount Xa1max corresponds to the time waveform obtained by rate-limiting the waveform of the required control amount Xa by the maximum change rate V1max and by upper-limit-limiting it by the maximum value Fc1max.

[0106] In the example shown in FIG. 10, the required control amount Xa remains constant over time and then decreases toward zero. To realize the required control amount Xa that changes in this way, the first control amount Xa1 must also decrease over time. The maximum rate of change when the first control amount Xa1 decreases (i.e., the slope of the time waveform of the first maximum control amount Xa1max) is V1max (a negative value). Therefore, for example, when the first control amount Xa1 is decreased from the sample time (k=m), the first maximum control amount Xa1max at each sample time k can be calculated by subtracting the negative maximum change amount ΔFc1max from the previous value, as when the required control amount Xa is increasing.

[0107] In addition, the information on the basic operating characteristics of the first actuator 7A stored in the storage device 72 for calculating the first maximum controlled variable Xa1max may include information on dynamic characteristics such as dead time characteristics and first-order lag characteristics. The first maximum controlled variable Xa1max may be calculated taking into consideration, for example, one or both of the dead time characteristics and the first-order lag characteristics.

[0108] In addition, in order to calculate the first maximum control amount Xa1max, at least one of the responsiveness and the output (control force Fc2) of the second actuator 3A combined with the first actuator 7A may be taken into consideration. Specifically, the first maximum control amount Xa1max may be calculated so that the required control amount Xa falls within a realizable range while taking into consideration at least one of these factors. <Step S302> In step S302 following step S300, the ECU 70 determines whether the first maximum control amount Xa1max that the first actuator 7A can output is insufficient for the required control amount Xa. This determination can be made, for example, based on whether the difference ΔXa1 is not zero. The difference ΔXa1 is a value (=Xa-Xa1max) obtained by subtracting the first maximum control amount Xa1max calculated in step S300 from the required control amount Xa calculated in step S106.

[0109] Specifically, when the required control amount Xa increases over time as shown in Fig. 10, the required control amount Xa is greater than the first maximum control amount Xa1max, and the above difference ΔXa1 is positive. Also, as shown in the figure, when the required control amount Xa, which remains constant, is greater than the first maximum control amount Xa1max (maximum value Fc1max), the difference ΔXa1 is positive. In this way, a positive difference ΔXa1 means that the first maximum control amount Xa1max alone is insufficient to provide a control amount.

[0110] Furthermore, the "insufficient control amount" determined in step S302 also occurs when the difference ΔXa1 is negative, as in the hatched area shown in Fig. 10. This hatched area occurs because the slope (solid line) of the required control amount Xa when it decreases due to, for example, a sudden return movement of the steering wheel by the driver of the vehicle 6 becomes larger than the slope of the first maximum control amount Xa1max. In this hatched area, the first maximum control amount Xa1max at each sample time k becomes larger than the required control amount Xa. That is, the difference ΔXa1 becomes negative.

[0111] <Step S304> If the determination result in step S302 is No (i.e., there is no shortage of the control amount), the process proceeds to step S304. For example, if the required control amount Xa is represented by a dashed line in FIG. 10, the determination result is No. In step S304, the ECU 70 commands the first actuator 7A to a first control amount Xa1 equal to the required control amount Xa calculated in step S106. As a result, the first actuator 7A is controlled to generate a control force Fc1 according to the commanded required control amount Xa. In addition, if the required control amount Xa can be satisfied by the first control amount Xa1 alone, the ECU 70 commands the first actuator 7A to use the entire required control amount Xa as the first control amount Xa1, and does not command the second actuator 3A regarding the required control amount Xa.

[0112] <Step S306> On the other hand, if the result of the determination in step S302 is Yes (i.e., if there is a shortage of the control amount), the process proceeds to step S306. For example, if the required control amount Xa is represented by a solid line in FIG. 10, the result of this determination is Yes.

[0113] In step S306, the ECU 70 calculates a second control amount Xa2 which is a control amount of the second actuator (active actuator) 3A. More specifically, the ECU 70 calculates the second control amount Xa2 at the next sample time (k+1). The second control amount Xa2 is calculated as a value required to compensate for the "deficiency of the control amount."

[0114] Specifically, the second control amount Xa2 is a value obtained by subtracting the first maximum control amount Xa1max calculated in step S300 from the required control amount Xa calculated in step S106, that is, the difference ΔXa1. The reason is that, as illustrated in Fig. 10, when the difference ΔXa1 is positive, it is necessary to increase the control force Fc2 of the second actuator 3A by the amount (difference ΔXa1) that is insufficient with only the first maximum control amount Xa1max of the required control amount Xa. On the other hand, when the difference ΔXa1 is negative, the control amount is insufficient by the negative difference ΔXa1 with only the first maximum control amount Xa1max. For this reason, it is necessary to control the control force Fc2 of the second actuator 3A so as to decrease by the negative difference ΔXa1.

[0115] <Step S308> In step S308 following step S306, the ECU 70 commands the first actuator 7A to use the first maximum control amount Xa1max calculated in step S300 as the first control amount Xa1, and commands the second actuator 3A to use the second control amount Xa2 calculated in step S306. As a result, the first actuator 7A is controlled to generate a control force Fc1 according to the commanded first maximum control amount Xa1max. Also, the second actuator 3A is controlled to generate a control force Fc2 according to the commanded second control amount Xa2.

[0116] In addition, in the example shown in FIG. 10, if the slope of the required control amount Xa that begins to decrease from the sample time (k=m) is the same as or smaller than the slope of the first maximum control amount Xa1max (dotted line), then during the period in which the required control amount Xa is greater than the first maximum control amount Xa1max, the second control amount Xa2 can be reduced to zero over time from the sample time (k=m), and the required control amount Xa can thereafter be satisfied by only the first control amount Xa1.

[0117] <Step S310> 9, after the required control amount Xm in the manual driving mode is calculated in step S102, the process proceeds to step S310. In step S310, the ECU 70 commands the calculated required control amount Xm to the second actuator 3A. As a result, the second actuator 3A is controlled to generate a control force Fc2 according to the commanded required control amount Xm. Alternatively, even in the manual driving mode, the ECU 70 may distribute the calculated required control amount Xm to the first actuator 7A and the second actuator 3A by the same processes as those in steps S300 to S308 in the automatic driving mode.

[0118] Effects According to the third embodiment described above, in the automatic driving mode, the first and second actuators 7A and 3A having different responsiveness are used in combination to realize the required control amount Xa. In the third embodiment, the required control amount Xa is also calculated using larger control gains Gar and Gap than in the manual driving mode. Therefore, the same effects as those of the first embodiment are achieved.

[0119] In addition, according to the third embodiment, when the first maximum control amount Xa1max that the first actuator 7A can output is insufficient for the required control amount Xa, the first maximum control amount Xa1max is commanded to the first actuator 7A, and the second control amount Xa2 to compensate for the insufficiency is commanded to the second actuator 3A. This allows the first actuator (air spring) 7A for vehicle height control to be actively used for posture control. When the required control amount Xa changes transiently, and when the output (control force Fc) is insufficient with only the first actuator 7A, the second actuator 3A with high responsiveness is used as a sub actuator to compensate for the response delay and output insufficiency of the first actuator 7A. This allows the frequency of use of the second actuator 3A, which consumes a lot of energy, to be reduced, so that responsiveness and output can be secured while saving energy (i.e., a high control effect can be obtained).

[0120] 3-4. Modification of calculation of first maximum control amount The first maximum control amount Xa1max may be calculated, for example, using the following method.

[0121] Here, roll control will be taken as an example for explanation. In an example where the required control amount Xar is calculated by multiplying the lateral acceleration LA by the control gain Gar (>control gain Gmr) (see formula (3)), the first maximum control amount Xa1max may be calculated by multiplying the lateral acceleration LA by the following control gain Ga1r. That is, the control gain Ga1r is a control gain equal to or greater than the control gain Gmr in the manual driving mode.

[0122] In this way, when the control gain Ga1r is used to calculate the first maximum control amount Xa1max, which is a control amount that can be realized by the first actuator 7A, the value of the control gain Ga1r may be equal to or greater than the control gain Gmr in the manual driving mode. In the autonomous driving mode, future operation information (for example, at least one operation amount of steering, acceleration, and deceleration at the future position of the vehicle 6) can be obtained in advance. Therefore, in the autonomous driving mode, the first maximum control amount X1max can be determined using the calculation method described here, taking into full consideration the response delay of the first actuator 7A, so that the first actuator 7A for vehicle height control can be used to the maximum extent for roll control without any trade-off.

[0123] Similarly, the first maximum control amount Xa1max for the pitch control may be calculated by multiplying the longitudinal acceleration FA by the following control gain Ga1p: That is, the control gain Ga1p is equal to or greater than the control gain Gmp in the manual driving mode.

[0124] In addition, with regard to the calculation of the first maximum control amount Xa1max of the first actuator 7A, if the maximum value of the first maximum control amount Xa1max is increased to the maximum value Fc1max (see FIG. 10), the following problem occurs. That is, as illustrated in FIG. 10, when the required control amount Xa is suddenly decreased due to a sudden return operation of the steering wheel, the second actuator 3A is required to generate a control force Fc2 in the opposite direction to the control force Fc1 generated by the first actuator 7A in order to realize the required control amount Xa (hatched area in the figure). In this hatched area, the response of the first actuator 7A is low, so the direction of the control force Fc1 and the direction of the control force Fc2 are opposite. This is not preferable from the viewpoint of energy consumption. Therefore, in order to reduce the occurrence of the occurrence of the control force Fc2 in the opposite direction to the control force Fc1, the maximum value of the first maximum control amount Xa1max may be limited to be smaller than the maximum value Fa1max.

[0125] 3-5. Restrictions on autonomous driving according to suspension performance According to the above-mentioned third embodiment, when the first maximum control amount Xa1max that the first actuator 7A for vehicle height control can output is insufficient for the required control amount Xa, the first maximum control amount Xa1max is commanded to the first actuator 7A, and the second control amount Xa2 for compensating for the insufficiency is commanded to the second actuator 3A. Instead of such an example, a restriction may be imposed on the automatic driving so that the first maximum control amount Xa1max alone does not cause a shortage of the control amount for the required control amount Xa. Specifically, the automatic driving control (for example, at least one of steering and acceleration / deceleration control) may be limited so that at least one of the lateral acceleration LA and the longitudinal acceleration FA that cause a shortage of the control amount does not occur.

[0126] 4. Other embodiments In the above-described first to third embodiments, the attitude control (roll control and pitch control) is performed on the four wheels 2 (i.e., all wheels) of the vehicle 1 or 6. However, the wheels that are the targets of the attitude control (control target wheels) are not necessarily limited to all wheels, and may be, for example, only the two front wheels or only the two rear wheels.

[0127] Also, unlike the above-described first to third embodiments, the attitude control to which the "calculation process" and "command process" according to the present disclosure are applied may be either roll control or pitch control. [Explanation of symbols]

[0128] 1, 6 cars 2 wheels 3.7 Suspension 3A, 7A Actuators 5. Spring structure 10 Vehicle Control System 20 Vehicle condition sensor 22 Lateral acceleration sensor 23 Front and rear acceleration sensor 30 Recognition Sensor 40 Position Sensor 50 Communication Equipment 60 Running gear 70 Electronic Control Unit (ECU) 90 Driving Environment Information

Claims

1. A vehicle capable of switching between a manual driving mode and an automatic driving mode, One or more actuators for controlling the suspension stroke of the controlled wheel; An electronic control unit; Equipped with The electronic control unit includes: a calculation process for calculating a required control amount for at least the roll control of the vehicle; a command process for commanding the requested control amount to the one or more actuators; Run In the calculation process, the electronic control unit increases a control gain included in the required controlled variable in the automatic driving mode compared to in the manual driving mode, the control gain includes at least a roll control gain included in the required control amount for the roll control, In the calculation process in the autonomous driving mode, the electronic control unit: setting an upper limit on a roll rate based on future operation information of the vehicle acquired during autonomous driving control in the autonomous driving mode; determining the roll control gain so that the one or more actuators generate a maximum control force within a range in which the roll rate does not exceed the upper limit; In the calculation process in the manual driving mode, the electronic control unit does not set an upper limit on the roll rate. A vehicle characterized by:

2. A vehicle capable of switching between a manual driving mode and an automatic driving mode, One or more actuators for controlling the suspension stroke of the controlled wheel; An electronic control unit; Equipped with The electronic control unit includes: a calculation process for calculating a required control amount for at least the pitch control of the roll control and the pitch control of the vehicle; a command process for commanding the requested control amount to the one or more actuators; Run In the calculation process, the electronic control unit increases a control gain included in the required controlled variable in the automatic driving mode compared to in the manual driving mode, the control gain includes at least a pitch control gain included in the required control amount for the pitch control, In the calculation process in the autonomous driving mode, the electronic control unit: setting an upper limit on a pitch rate based on future operation information of the vehicle acquired during autonomous driving control in the autonomous driving mode; determining the pitch control gain such that the one or more actuators generate a maximum control force within a range in which the pitch rate does not exceed the upper limit; In the calculation process in the manual driving mode, the electronic control unit does not set an upper limit on the pitch rate. A vehicle characterized by:

3. In the calculation process in the autonomous driving mode, the electronic control unit: performing a low-pass filter process on the future operation information; The required control amount is calculated based on the future operation information after the low-pass filter process.

3. A vehicle as claimed in claim 1 or 2.

4. In the command processing, when the low-pass filter processing is performed, the electronic control unit advances the timing of issuing a command of the required control amount to the one or more actuators, compared to when the low-pass filter processing is not performed.

4. The vehicle according to claim 3.

5. The one or more actuators include: A first actuator; a second actuator having a higher responsiveness than the first actuator; Including, In the command processing, the electronic control unit: When a first maximum control amount, which is a maximum value of a first control amount that the first actuator can output, is insufficient for the required control amount, the first maximum control amount is commanded to the first actuator, and a second control amount for compensating for the shortage is commanded to the second actuator. A vehicle according to any one of claims 1 to 4.

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