Vehicle control system and vehicle control device

Abstract

To provide a vehicle control system and a vehicle control device which reduce fluctuation of vertical force at wheel and thereby enabling safety of a vehicle to be enhanced.SOLUTION: A vehicle control system comprises: a plurality of variable dampers 6 each arranged between a vehicle body 1 and 4 wheels 2 with generative force thereof adjustable in a range between weak and strong force; and an ECU 21 which variably controls the generative force of the variable dampers 6. When a signal is input from a braking determination section 31 which independently brakes 4 wheels 2, the ECU 21 adjusts the generative force of the variable dampers 6 so as to reduce fluctuation of vertical force at wheel applied to a ground surface with the variable dampers 6.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present disclosure relates to a vehicle control system and a vehicle control device that control an actuator that varies the force that suppresses relative displacement between a vehicle body and a wheel. [Background technology]

[0002] The control device disclosed in Patent Document 1 executes either a compression stroke hard-soft switching control, which switches the damping force characteristics of the damper provided on the wheel side that increases the wheel load, to hard in the early stage of the compression stroke and soft in the later stage, or an extension stroke soft-hard switching control, which switches the damping force characteristics to soft in the early stage of the extension stroke and hard in the later stage. This makes it possible to control the responsiveness and absolute amount of wheel load increase / decrease, and to control the vehicle's driving more safely. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2012-66677 Summary of the Invention [Problem to be solved by the invention]

[0004] The control device disclosed in Patent Document 1 executes either hard-soft switching control for the compression stroke or soft-hard switching control for the extension stroke. However, when such control is performed, the fluctuation of the ground contact load tends to increase, and there is a risk that the stability of the vehicle will decrease when, for example, an anti-lock brake system (ABS) is activated.

[0005] An object of one embodiment of the present invention is to provide a vehicle control system and a vehicle control device that can reduce ground load fluctuations and improve vehicle stability. [Means for solving the problem]

[0006] A vehicle control system according to one embodiment of the present invention comprises: a plurality of force generating mechanisms, each of which is provided between a body of a vehicle and four wheels, and each of which is capable of adjusting the force generated by the force generating mechanisms between soft and hard modes; and control means for variably controlling the forces generated by the force generating mechanisms, wherein the control means comprises: an attitude stability control unit that outputs an attitude stability control command value for controlling the force generating mechanisms in accordance with an inputted change in attitude of the vehicle; a ride comfort control unit that outputs a ride comfort control command value for controlling the force generating mechanisms in accordance with an inputted sprung vibration of the vehicle; a cooperative control command unit that outputs a cooperative control command value for controlling the force generating mechanisms when a signal is inputted from a braking / driving determination unit that independently brakes / drives the four wheels; and a control command selection unit that selects the highest command value outputted from the attitude stability control command value, the ride comfort control command value, and the cooperative control command value. Based on the command value from the control command selection unit The force generated by the force generating mechanism is adjusted.

[0007] A vehicle control device according to one embodiment of the present invention is a vehicle control device that controls actuators that are provided between a body of a vehicle and four wheels, respectively, and that vary the force generated between the body and the wheels, and the vehicle control device includes: an attitude stability control unit that outputs an attitude stability control command value for controlling the actuators in accordance with an input attitude change of the vehicle; a ride comfort control unit that outputs a ride comfort control command value for controlling the actuators in accordance with an input sprung vibration of the vehicle; a cooperative control command unit that outputs a cooperative control command value for controlling the force generated by the actuators when a signal is input from a braking / driving determination unit that independently brakes / drives the four wheels; and a control command selection unit that selects the highest command value output from the attitude stability control command value, the ride comfort control command value, and the cooperative control command value, Based on the command value from the control command selection unit The actuator is controlled. [Effects of the Invention]

[0008] According to one embodiment of the present invention, it is possible to reduce the ground load fluctuation and improve the stability of the vehicle. [Brief explanation of the drawings]

[0009] [Figure 1] 1 is an overall configuration diagram showing a four-wheeled automobile to which an ECU according to an embodiment of the present invention is applied; [Figure 2] FIG. 2 is a diagram schematically showing a shock absorber mounted on the automobile in FIG. [Figure 3] FIG. 2 is a block diagram showing the configuration of an ECU according to the first embodiment. [Figure 4] FIG. 4 is a block diagram showing the configuration of an anti-divesquat control unit in FIG. 3. [Figure 5] FIG. 4 is a block diagram showing the configuration of an anti-roll control unit in FIG. 3. [Figure 6] FIG. 4 is a characteristic diagram showing time changes in vehicle speed, longitudinal acceleration, pitch rate, pitch angle, and current value supplied to the variable damper of each wheel for the first embodiment and a comparative example. [Figure 7] FIG. 4 is a characteristic diagram showing the change over time in damping force generated by a variable damper of each wheel for the first embodiment and a comparative example. [Figure 8] FIG. 4 is a characteristic diagram showing changes in wheel load of each wheel over time for the first embodiment and a comparative example. [Figure 9] FIG. 10 is a block diagram showing the configuration of an ECU according to a second embodiment. [Figure 10] FIG. 10 is an explanatory diagram showing the relationship between the current value supplied to the variable damper of the left front wheel and the wheel load fluctuation RMS value. [Figure 11] FIG. 10 is an explanatory diagram showing the relationship between the current value supplied to the variable damper of the left rear wheel and the wheel load fluctuation RMS value. [Figure 12] FIG. 10 is a characteristic diagram showing the relationship between the piston speed and damping force of the variable damper for the left front wheel. [Figure 13] FIG. 10 is a characteristic diagram showing the relationship between the piston speed and the damping force of the variable damper for the left rear wheel. [Figure 14] FIG. 10 is a block diagram showing the configuration of an ECU according to a third embodiment. [Figure 15] 10A and 10B are diagrams illustrating a state transition based on a relative acceleration between a sprung portion and an unsprung portion. [Figure 16] FIG. 4 is a characteristic diagram showing time variations in relative acceleration, state, and command value. [Figure 17] FIG. 10 is a block diagram showing the configuration of an ECU according to a fourth embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0010] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A vehicle control system and a vehicle control device according to an embodiment of the present invention will be described in detail below with reference to the accompanying drawings, taking as an example a case where the system is applied to a four-wheeled automobile.

[0011] 1 to 5 show a first embodiment of the present invention. In FIGS. 1 and 2, a vehicle body 1 constitutes the body of a vehicle. For example, left and right front wheels and left and right rear wheels (hereinafter collectively referred to as wheels 2) are provided on the underside of the vehicle body 1. These wheels 2 are configured to include tires 3. The tires 3 act as springs that absorb small irregularities in the road surface. The vehicle body 1 and wheels 2 constitute the vehicle.

[0012] The suspension device 4 is installed between the vehicle body 1 and the wheel 2. The suspension device 4 is composed of a suspension spring 5 (hereinafter referred to as the spring 5) and an adjustable damping shock absorber (hereinafter referred to as the variable damper 6) installed in parallel with the spring 5 and interposed between the vehicle body 1 and the wheel 2.

[0013] The variable dampers 6 of the suspension device 4 are provided between the vehicle body 1 and each of the four wheels 2. The variable dampers 6 are actuators that vary the force that suppresses relative displacement between the vehicle body 1 and the wheels 2. The variable dampers 6 vary the force that is generated between the vehicle body 1 and the wheels 2. The variable dampers 6 are also force generating mechanisms that adjust the force between the vehicle body 1 and the wheels 2. The force that the variable dampers 6 generate can be adjusted between soft and hard.

[0014] The variable damper 6 is configured using a damping force adjustable hydraulic shock absorber. As shown in Fig. 2, the variable damper 6 is provided with a damping force variable actuator 7 consisting of a damping force adjustment valve and the like in order to continuously adjust the characteristics of the generated damping force (i.e., the damping force characteristics) from hard characteristics (hard characteristics) to soft characteristics (soft characteristics). The damping force variable actuator 7 is a damping force adjustment unit that adjusts the damping force according to the supplied current (drive current).

[0015] The variable damping force actuator 7 does not necessarily have to be configured to continuously adjust the damping force characteristics, but may be configured to adjust the damping force in multiple stages, for example, two or more stages. The variable damper 6 may be of a pressure control type or a flow rate control type.

[0016] CAN8 (controller area network) is a serial communication unit mounted on the vehicle body 1. CAN8 performs in-vehicle multiplex communication between a large number of electronic devices mounted on the vehicle and the ECU 21. CAN8 transmits vehicle driving information by CAN signals consisting of serial signals. In this case, the vehicle driving information transmitted through CAN8 includes, for example, yaw rate, steering angle, vehicle speed, longitudinal acceleration, brake fluid pressure, engine torque, etc.

[0017] In addition, the vehicle driving information transmitted through the CAN 8 also includes a signal from a braking / driving determination unit 31. The braking / driving determination unit 31 brakes or drives the four wheels 2 independently. The braking / driving determination unit 31 includes, for example, an ABS, a TCS (Traction Control System), and an ECS (Electronic Stability Control). The signal from the braking / driving determination unit 31 is, for example, an ABS / TCS / ECS operation flag that indicates that any of the ABS, TCS, and ECS has operated.

[0018] The sprung acceleration sensor 9 is provided on the vehicle body 1 and detects vertical vibration acceleration on the sprung side of the vehicle body 1. The sprung acceleration sensor 9 constitutes a sprung state detection means that detects sprung vibration. The sprung state detection means is not limited to one that detects sprung vibration, and may be one that estimates sprung vibration based on vehicle operation information included in a CAN signal, for example.

[0019] For example, a total of three sprung acceleration sensors 9 are provided on the vehicle body 1. In this case, the sprung acceleration sensors 9 are attached to the vehicle body 1, for example, at positions near the upper ends of the variable dampers 6 on the left and right front wheel sides, and at a midpoint between the left and right rear wheels. The sprung acceleration sensors 9 detect vertical vibration acceleration on the vehicle body 1 side, which is the sprung side, and output the detection signals to the ECU 21.

[0020] The unsprung acceleration sensor 10 is provided on the wheel 2 side of the vehicle. A total of two unsprung acceleration sensors 10 are provided on the vehicle. Specifically, one unsprung acceleration sensor 10 is provided on the right front wheel and one on the left front wheel of the vehicle, for example. The unsprung acceleration sensor 10 detects vertical vibration acceleration on the wheel 2 side, which is the unsprung side, and outputs the detection signal to the ECU 21.

[0021] The ECU 21 constitutes a vehicle control device that controls the suspension device 4. The ECU 21 controls the variable damper 6 that varies the force generated between the vehicle body 1 and the wheels 2. Here, the ECU 21 is a control means that controls the force generated by the variable damper 6 (force generating mechanism).

[0022] The ECU 21 includes a processor 22 as a control unit. The processor 22 is configured by a microcomputer or the like. The ECU 21 includes a storage unit (not shown) including a ROM, a RAM, a non-volatile memory, etc. The processor 22 controls the damping force of the variable damper 6 by executing a program stored in the storage unit.

[0023] 2, the input side of the ECU 21 is connected to the CAN 8, the sprung acceleration sensor 9, the unsprung acceleration sensor 10, etc., and the output side is connected to the damping force variable actuator 7 of the variable damper 6, etc. The processor 22 reads vehicle driving information from the CAN 8 via serial communication. The processor 22 reads the sprung acceleration sensor value (sprung acceleration) based on a detection signal from the sprung acceleration sensor 9. The processor 22 reads the unsprung acceleration sensor value (unsprung acceleration) based on a detection signal from the unsprung acceleration sensor 10.

[0024] 3, the ECU 21 includes an observer 23 that determines vehicle behavior such as the relative speed and relative acceleration between the sprung and unsprung parts. In addition, the ECU 21 includes a ride comfort control unit 24, an attitude stability control unit 25, an ABS / TCS / ECS cooperative control unit 29, and a control command selection unit 30, which will be described later.

[0025] The observer 23 determines vehicle behavior based on the sprung acceleration input from the sprung acceleration sensor 9 and the unsprung acceleration input from the unsprung acceleration sensor 10. The observer 23 is equipped with a subtractor and an integrator (neither of which is shown). The sprung acceleration and the unsprung acceleration are input to the observer 23. The subtractor subtracts the unsprung acceleration from the sprung acceleration to determine the relative acceleration, which is the difference between these. An integrator integrates the sprung acceleration to determine the sprung velocity. Another integrator integrates the relative acceleration to determine the relative velocity. The observer 23 outputs the sprung velocity, the relative velocity, and the relative acceleration.

[0026] In the first embodiment, the observer 23 obtains the relative velocity from the sprung acceleration and the unsprung acceleration. For example, if the suspension device 4 of each wheel is provided with a stroke sensor, the relative velocity, relative acceleration, etc. may be obtained based on the detected value of the stroke sensor. Alternatively, the relative velocity, relative acceleration, etc. may be estimated based on information input from the CAN 8 (vehicle driving information).

[0027] The ride comfort control unit 24 outputs a ride comfort control command to improve the ride comfort of the vehicle. The ride comfort control unit 24 outputs a ride comfort control command value to control the variable damper 6 in accordance with the input sprung vibration of the vehicle. The sprung vibration of the vehicle includes, for example, the sprung velocity and the relative velocity. The sprung vibration of the vehicle may be directly detected by a sensor or the like, or may be estimated based on, for example, the sprung acceleration or the like. The ride comfort control unit 24 acquires the sprung velocity and the relative velocity (piston velocity) between the sprung and unsprung parts from the observer 23. The ride comfort control unit 24 outputs a ride comfort control command based on the sprung velocity and the relative velocity of each wheel. At this time, the ride comfort control command is, for example, a control command value (current value) that serves as a current command signal to the damping force variable actuator 7. The ride comfort control unit 24 outputs a ride comfort control command value to reduce the up and down vibration of the sprung part from the sprung velocity and the relative velocity based on, for example, the skyhook control law.

[0028] In the first embodiment, the ride comfort control unit 24 outputs a ride comfort control command based on skyhook control. However, the present invention is not limited to this, and the ride comfort control unit may output a ride comfort control command based on, for example, bilinear optimal control or H∞ control.

[0029] The attitude stability control unit 25 outputs an attitude stability control command for improving the attitude stability (handling stability) of the vehicle. The longitudinal acceleration and lateral acceleration transmitted from the CAN 8 are input to the attitude stability control unit 25. The attitude stability control unit 25 outputs an attitude stability control command based on the longitudinal acceleration and lateral acceleration. The attitude stability control unit 25 outputs an attitude stability control command value for controlling the variable damper 6 in accordance with the input attitude change of the vehicle.

[0030] When the change in vehicle attitude exceeds a predetermined value, the attitude stability control unit 25 outputs an attitude stability control command to cause the variable damper 6 to have a hard characteristic. The change in vehicle attitude includes, for example, turning, acceleration, deceleration, etc. Turning of the vehicle may be detected or estimated based on, for example, the steering angle or lateral acceleration. Acceleration or deceleration of the vehicle may be detected or estimated based on, for example, the brake fluid pressure or the engine motor torque.

[0031] Forward / backward acceleration and lateral acceleration are input to the attitude stability control unit 25. As shown in Fig. 3, the attitude stability control unit 25 includes an anti-dive squat control unit 26, an anti-roll control unit 27, and a preliminary control command selection unit 28.

[0032] The anti-divesquat control unit 26 outputs an anti-divesquat control command to suppress longitudinal tilt of the vehicle due to acceleration or deceleration of the vehicle. The longitudinal acceleration is input to the anti-divesquat control unit 26. As shown in Fig. 4, the anti-divesquat control unit 26 includes a differentiator 26A, a front gain multiplication unit 26B, an inverter 26C, a rear gain multiplication unit 26D, a relative velocity calculation unit 26E, and a damping force characteristic processing unit 26F.

[0033] Differentiator 26A differentiates the longitudinal acceleration to calculate a jerk in the longitudinal direction of the vehicle (longitudinal jerk). Front gain multiplication unit 26B multiplies the longitudinal jerk by a front gain and outputs a target damping force on the front side. Rear gain multiplication unit 26D multiplies the longitudinal jerk multiplied by "-1" by inversion unit 26C by a rear gain and outputs a target damping force on the rear side.

[0034] For example, if the derivative value of the longitudinal acceleration (longitudinal jerk) is negative, a dive behavior is predicted, so it is necessary to derive a target damping force for the front side that takes into account damper compression, and for the rear side that takes into account damper extension. Taking this into consideration, the inversion unit 26C multiplies the longitudinal jerk by "-1" before multiplying it by the rear gain. That is, here, the extension side of the damper is made positive, and the compression side of the damper is made negative.

[0035] The relative velocity calculation unit 26E calculates the relative velocity from the longitudinal jerk. The damping force characteristic processing unit 26F is configured with, for example, a damping force map that indicates the relationship between the target damping force and relative velocity and the command value (control command) to be output to the variable damper 6. The damping force characteristic processing unit 26F outputs a control command for controlling the front-side variable damper 6 based on the front-side target damping force and relative velocity. The damping force characteristic processing unit 26F outputs a control command for controlling the rear-side variable damper 6 based on the rear-side target damping force and relative velocity. These control commands are anti-dive squat control commands, and are, for example, control command values (current values) that become a command signal for current to the damping force variable actuator 7.

[0036] Anti-roll control unit 27 outputs an anti-roll control command for suppressing the roll behavior of the vehicle. Lateral acceleration is input to anti-roll control unit 27. As shown in Fig. 5, anti-roll control unit 27 includes a differentiator 27A, a left wheel gain multiplication unit 27B, an inverter 27C, a right wheel gain multiplication unit 27D, a gain multiplication unit 27E, a pitch control processing unit 27F, a relative speed calculation unit 27G, an adder 27H, and a damping force characteristic processing unit 27J.

[0037] Differentiator 27A differentiates the lateral acceleration to calculate a jerk (lateral jerk) in the lateral direction (left-right direction) of the vehicle. Left wheel gain multiplication unit 27B multiplies the lateral jerk by the left wheel gain and outputs a target damping force for the left wheel. Right wheel gain multiplication unit 27D multiplies the lateral jerk multiplied by "-1" by inversion unit 27C by the right wheel gain and outputs a target damping force for the right wheel.

[0038] For example, if the derivative value of the lateral acceleration (lateral jerk) is positive, the vehicle body is predicted to sink toward the right wheel, so the left wheel side needs to be provided with an extension side damper, and the right wheel side needs to be provided with a contraction side damper. Taking this into consideration, the inversion unit 27C multiplies the lateral jerk by "-1" before multiplying it by the right wheel gain.

[0039] The anti-roll control unit 27 expands on the basic concept of G-vectoring, which improves driving performance, of "controlling longitudinal movement in accordance with lateral movement," and controls pitch movement in accordance with lateral movement. To this end, the gain multiplication unit 27E multiplies the lateral jerk by a gain. The pitch control processing unit 27F derives a target damping force for pitch control that conforms to the expanded concept of G-vectoring, based on the lateral jerk multiplied by the gain.

[0040] Relative velocity calculation unit 27G calculates the relative velocity from the lateral jerk. Adder 27H adds the target damping force on the left wheel for pitch control to the target damping force on the left wheel for roll suppression, and outputs the target damping force on the left wheel for roll and pitch control. Adder 27H adds the target damping force on the right wheel for pitch control to the target damping force on the right wheel for roll suppression, and outputs the target damping force on the right wheel for roll and pitch control.

[0041] The damping force characteristic processing unit 27J is configured with, for example, a damping force map that indicates the relationship between the target damping force and relative velocity and the command value (control command) to be output to the variable damper 6. The damping force characteristic processing unit 27J outputs a control command for controlling the variable damper 6 on the left wheel side based on the target damping force and relative velocity on the left wheel side. The damping force characteristic processing unit 27J outputs a control command for controlling the variable damper 6 on the right wheel side based on the target damping force and relative velocity on the right wheel side. These control commands are anti-roll control commands, and are, for example, control command values (current values) that become a command signal for a current to the damping force variable actuator 7.

[0042] As shown in Fig. 3, an anti-dive squat control command and an anti-roll control command are input to the preliminary control command selector 28. The preliminary control command selector 28 compares the anti-dive squat control command with the anti-roll control command and selects the control command with the larger value (the value on the hardware side). The preliminary control command selector 28 outputs the value of the selected control command as the attitude stability control command value.

[0043] The ABS / TCS / ECS cooperative control unit 29 includes a target damping force calculation unit 29A and a damping force map 29B. The relative speed is input to the ABS / TCS / ECS cooperative control unit 29 from the observer 23, and an ABS / TCS / ECS operation flag is input as a signal from the braking / driving determination unit 31 via the CAN 8.

[0044] When the ABS / TCS / ECS operation flag detects operation of any one of the ABS, TCS, and ECS, the target damping force calculation unit 29A calculates the optimal target damping force for suppressing ground load variation based on the damping ratio ζopt, coefficient Cc, and relative speed using the following equation 1. Specifically, the target damping force calculation unit 29A obtains the optimal target damping force for suppressing ground load variation by multiplying the damping ratio ζopt, coefficient Cc, and relative speed. On the other hand, when the ABS / TCS / ECS operation flag does not detect operation of all of the ABS, TCS, and ECS, the target damping force calculation unit 29A sets the target damping force to 0 (zero).

[0045] In this case, the damping ratio ζopt is the optimum damping ratio for suppressing load fluctuations. The coefficient Cc is the critical damping coefficient. The damping ratio ζopt and the coefficient Cc are obtained in advance, for example, by experiments using an actual vehicle or simulations.

[0046]

number

[0047] Damping force characteristics are stored in advance in the damping force map 29B. The target damping force is input to the damping force map 29B from the target damping force calculation unit 29A, and the relative velocity is also input to the damping force map 29B. Based on the target damping force and the relative velocity, the damping force map 29B outputs a cooperative control command corresponding to these. At this time, the cooperative control command is, for example, a control command value (current value) that serves as a command signal for a current to the damping force variable actuator 7.

[0048] The control command selection unit 30 compares the ride comfort control command, attitude stability control command, and cooperative control command, and selects the control command with the larger value. The control command selection unit 30 outputs the selected control command as the final control command. Specifically, the control command selection unit 30 selects the value on the hard side from the ride comfort control command, attitude stability control command, and cooperative control command. At this time, the control command selection unit 30 performs the same processing for the control commands of each of the four wheels. A drive current based on the final control command is supplied to the damping force variable actuator 7 of the variable damper 6. As a result, the damping force of the variable damper 6 is controlled by the ECU 21.

[0049] The ECU 21 according to the first embodiment has the above-described configuration, and its operation will now be described.

[0050] When vertical vibrations occur due to unevenness of the road surface while the vehicle is traveling, various vehicle driving information, sprung acceleration, unsprung acceleration, etc. are input to the ECU 21 from the CAN 8, the sprung acceleration sensor 9, and the unsprung acceleration sensor 10. At this time, the observer 23 determines the sprung velocity and the relative velocity based on the sprung acceleration and the unsprung acceleration.

[0051] The ride comfort control unit 24 of the ECU 21 outputs a ride comfort control command to improve the ride comfort of the vehicle based on the sprung velocity and the relative velocity. The attitude stability control unit 25 of the ECU 21 outputs an attitude stability control command to improve the attitude stability of the vehicle based on the lateral acceleration and longitudinal acceleration input from the CAN 8. At this time, the attitude stability control command has a value that suppresses dive squat and roll.

[0052] When the ABS / TCS / ECS cooperative control unit 29 of the ECU 21 detects that none of the ABS, TCS, and ECS are operating, it outputs a cooperative control command corresponding to a target damping force of 0 (zero). In this case, the cooperative control command is a value on the soft side. At this time, the control command selection unit 30 of the ECU 21 selects a value on the hard side of the ride comfort control command or the attitude stability control command. As a result, the ECU 21 can achieve both ride comfort and attitude stability.

[0053] Meanwhile, when the ABS / TCS / ECS cooperative control unit 29 of the ECU 21 detects operation of any of the ABS, TCS, and ECS, it calculates a target damping force that is optimal for suppressing ground load variation and outputs a cooperative control command corresponding to this target damping force. At this time, the control command selection unit 30 of the ECU 21 selects a value on the hard side from the ride comfort control command, the attitude stability control command, and the cooperative control command. As a result, when any of the ABS, ECS, and TCS is activated, the ECU 21 can reduce ground load variation and improve vehicle stability.

[0054] Next, to confirm the vibration damping effect of the ECU 21, a control example in which the ABS / TCS / ECS cooperative control unit 29 is omitted was used as a comparative example to compare the vibration damping performance, etc., of the control according to the first embodiment through a vehicle simulation. The simulation results are shown in FIGS. 6 to 8. As shown in FIG. 6, in the first embodiment, the command value (current value) increases when the vehicle is decelerating while the ABS is activated, compared to the comparative example. Furthermore, in the first embodiment, the timing at which the longitudinal acceleration reaches 0 (zero) is also earlier than in the comparative example. This indicates that the vehicle can be stopped earlier in the first embodiment than in the comparative example. Furthermore, as shown in FIG. 7, in the first embodiment, the damping force is greater at the timing at which the command value increases, compared to the comparative example. Furthermore, as shown in FIG. 8, in the first embodiment, the wheel load fluctuation is smaller than in the comparative example, and the ground load fluctuation is also reduced.

[0055] Thus, the vehicle control system of the first embodiment includes a plurality of variable dampers 6 (force generating mechanisms) that are respectively provided between the vehicle body 1 and the four wheels 2 and whose generated force can be adjusted between soft and hard, and an ECU 21 (control means) that variably controls the generated force of the variable dampers 6. When a signal is input from a braking / driving determination unit 31 (ABS, ECS, TCS) that independently brakes / drives (braks or drives) the four wheels 2, the ECU 21 adjusts the generated force of the variable dampers 6 so that fluctuations in the road load caused by the variable dampers 6 are reduced.

[0056] That is, the ECU 21 (vehicle control device) controls variable dampers 6 (actuators) that are provided between the vehicle body 1 and each of the four wheels 2 of the vehicle and that vary the force generated between the vehicle body 1 and the wheels 2. When a signal is input from a braking / driving determination unit 31 (ABS, ECS, TCS) that independently brakes and drives the four wheels 2, the ECU 21 controls the variable dampers 6 so that fluctuations in the contact load between the wheels 2 and the road surface due to the force generated by the variable dampers 6 are reduced.

[0057] As a result, when any of the ABS, ECS, and TCS is activated, the ECU 21 controls the variable damper 6 so as to reduce the ground contact load fluctuation between the wheel 2 and the road surface due to the force generated by the variable damper 6. As a result, when any of the ABS, ECS, and TCS is activated, the ground contact load fluctuation is reduced, thereby improving vehicle stability. Furthermore, in the first embodiment, ground contact load fluctuation caused by road surface input can be suppressed on a rough road surface, thereby shortening the braking distance. That is, in the first embodiment, when stability is of the utmost importance, such as when any of the ABS, ECS, and TCS is activated, the damping ratio is set to minimize the ground contact load fluctuation, giving top priority to road contact. As a result, in the first embodiment, acceleration / deceleration performance and cornering performance can be improved.

[0058] 1, 2, and 9 show a second embodiment of the present invention. The second embodiment is characterized in that the ABS / TCS / ECS cooperative control unit calculates a current command value that is optimal for suppressing a preset ground load variation without calculating a target damping force when a signal is input from the braking / driving determination unit. In the second embodiment, the same components as those in the first embodiment are designated by the same reference numerals, and their description will be omitted.

[0059] The ECU 41 according to the second embodiment is configured in substantially the same manner as the ECU 21 according to the first embodiment. The ECU 41 constitutes a vehicle control device (control means) that controls the suspension device 4. The ECU 41 is a controller that controls the force generated by the variable damper 6 (force generating mechanism). As shown in FIG. 2, the ECU 41 includes a processor 42 as a control unit. The processor 42 is configured by a microcomputer or the like. The processor 42 controls the damping force of the variable damper 6 by executing a program stored in a storage unit (not shown). The input side of the ECU 41 is connected to the CAN 8, the sprung acceleration sensor 9, the unsprung acceleration sensor 10, etc., and the output side is connected to the variable damper 6, etc.

[0060] The ECU 41 includes the ride comfort control unit 24, the attitude stability control unit 25, the ABS / TCS / ECS cooperative control unit 43, and the control command selection unit 30, similar to the ECU 21 according to the first embodiment.

[0061] 9, the ABS / TCS / ECS cooperative control unit 43 receives an ABS / TCS / ECS operation flag as a signal from the braking / driving determination unit 31 via CAN 8. When the ABS / TCS / ECS operation flag detects that the ABS, TCS, or ECS is operating, the ABS / TCS / ECS cooperative control unit 43 calculates a preset current Ifopt as a front wheel command value and a preset current Iropt as a rear wheel command value using the following equation 2. At this time, the ABS / TCS / ECS cooperative control unit 43 outputs the front wheel command value and the rear wheel command value as cooperative control commands.

[0062] The front wheel command value is an optimum current command value for the front wheels for suppressing ground load fluctuations. The rear wheel command value is an optimum current command value for the rear wheels for suppressing ground load fluctuations. In this case, the currents Ifopt and Iropt are determined based on, for example, a damping force characteristic map of the variable damper 6 and a value of a representative relative speed (e.g., 0.6 m / s) at which ground load fluctuations occur. In this case, the target damping force may be calculated by substituting the value of a representative relative speed (e.g., 0.6 m / s) at which ground load fluctuations occur into Equation 1, and then the currents Ifopt and Iropt may be determined based on this target damping force and the damping force characteristic map. Note that the damping ratio ζopt and coefficient Cc tend to differ between the front and rear wheels. For this reason, the currents Ifopt and Iropt generally have different values.

[0063]

number

[0064] On the other hand, when the ABS / TCS / ECS operation flags do not detect that all of the ABS, TCS, and ECS are operating, the ABS / TCS / ECS cooperative control unit 43 outputs a current value that softens the damping force as a cooperative control command.

[0065] Thus, the second embodiment configured as described above can also achieve the same effects as the first embodiment. Furthermore, in the second embodiment, the ABS / TCS / ECS cooperative control unit 43 outputs a preset current value as a cooperative control command depending on whether the ABS, TCS, or ECS is activated. This reduces the load of calculation processing when calculating the cooperative control command. Therefore, when any of the ABS, TCS, or ECS is activated, load fluctuations can be suppressed through simple calculation processing.

[0066] In the second embodiment, the current command value of the cooperative control command is determined based on a representative relative speed value at which ground load fluctuation occurs. However, the present invention is not limited to this. For example, the current command value that minimizes load fluctuation for a variable damper 6 mounted on a vehicle may be experimentally determined. FIGS. 10 and 11 show an example of the relationship between the current value and the root mean square (RMS) value of the wheel load fluctuation for the front and rear wheels. The ground load fluctuation RMS value corresponds to the ground load fluctuation. While FIGS. 10 and 11 show an example of the characteristics of the left front wheel FL and the left rear wheel RL, the characteristics of the right front wheel FR and the right rear wheel RR are similar. Furthermore, FIGS. 12 and 13 show an example of the relationship between the piston speed and the damping force of the variable dampers 6 for the front and rear wheels.

[0067] As shown in FIG. 10, it can be seen that for the front wheels, the ground contact load fluctuation is smallest at a command value of 0.9 A, for example. It can also be seen that for the rear wheels, the ground contact load fluctuation is smallest at a command value of 1.6 A. From this result, taking into consideration the amount of power consumption and unsprung road contact, it is thought that the appropriate values for the front wheels are 0.9 A and for the rear wheels are 1.3 A. Therefore, when any of the ABS, TCS, or ECS is activated, the ABS / TCS / ECS cooperative control unit 43 may set the front wheel command value of the cooperative control command to 0.9 A and the rear wheel command value of the cooperative control command to 1.3 A.

[0068] 1, 2, and 14 show a third embodiment of the present invention. The third embodiment is characterized in that the unsprung vibration damping control unit outputs a current command value that is optimal for suppressing ground load fluctuations when a signal is input from the braking / driving determination unit. In the third embodiment, the same components as those in the first embodiment described above are denoted by the same reference numerals, and their description will be omitted.

[0069] The ECU 51 according to the third embodiment is configured in substantially the same manner as the ECU 21 according to the first embodiment. The ECU 51 constitutes a vehicle control device (control means) that controls the suspension device 4. The ECU 51 is a controller that controls the force generated by the variable damper 6 (force generating mechanism). As shown in FIG. 2, the ECU 51 includes a processor 52 as a control unit. The processor 52 is configured by a microcomputer or the like. The processor 52 controls the damping force of the variable damper 6 by executing a program stored in a storage unit (not shown). The input side of the ECU 51 is connected to the CAN 8, the sprung acceleration sensor 9, the unsprung acceleration sensor 10, etc., and the output side is connected to the variable damper 6, etc.

[0070] Similar to the ECU 21 according to the first embodiment, the ECU 51 includes a ride comfort control unit 24, a posture stability control unit 25, and a control command selection unit 30. In addition, the ECU 51 includes an unsprung mass damping control unit 53.

[0071] As shown in Fig. 14, the unsprung vibration damping control unit 53 outputs an unsprung vibration damping control command to suppress vibration in the unsprung parts. Specifically, the unsprung vibration damping control unit 53 determines whether the vehicle has traveled over a protrusion using the relative acceleration output from the observer 23. The positive and negative slopes of the characteristic curve showing the relative acceleration in Fig. 16 roughly correspond to the extension stroke and compression stroke of the variable damper 6, respectively. The unsprung vibration damping control unit 53 uses first to fourth relative acceleration threshold values Kα1 to Kα4 as threshold values used in the determination process.

[0072] When performing the determination process, the unsprung vibration damping control unit 53 uses the relative acceleration corresponding reference state Jα0 and the first to third relative acceleration corresponding states Jα1 to Jα3 (see FIG. 15). Here, the relative acceleration corresponding reference state Jα0 and the first to third relative acceleration corresponding states Jα1 to Jα3 refer to the following states.

[0073] The relative acceleration-corresponding reference state Jα0 refers to a state (initial state) in which the vehicle starts traveling and the magnitude of the extension and contraction of the operating stroke of the variable damper 6 is less than a predetermined value. In the relative acceleration-corresponding reference state Jα0, the unsprung vibration damping control unit 53 performs control to output an unsprung vibration damping control command to soften the damping force characteristics of the variable damper 6 (hereinafter referred to as soft command value control). Note that the relative acceleration-corresponding reference state Jα0 indicates an initial state in which no control related to the protrusion is performed, and is referred to as soft for the sake of convenience, but is not limited to this.

[0074] The relative acceleration-based first state Jα1 refers to a state in which (i) the first timer measures (counts), and (ii) the command value soft control is performed (command value=soft). The second relative acceleration-based state Jα2 refers to a state in which (i) the second timer measures (counts), and (ii) the command value soft control is performed (command value=soft). The third relative acceleration-responsive state Jα3 is a state in which (i) the third timer measures (counts) time, and (ii) a control is performed to output an unsprung vibration control command (cooperative control command) that changes the damping force characteristics of the variable damper 6 to characteristics that suppress ground load fluctuations (the command value = the current value for suppressing ground load fluctuations).

[0075] In the third embodiment, transitions among the states Jα0, Jα1, Jα2, and Jα3 are made based on the count values of the first, second, and third timers and the relative acceleration.

[0076] The unsprung vibration damping control unit 53 performs a protrusion-crossing determination process based on the relative acceleration, and outputs an unsprung vibration damping control command based on the result of this determination process. The unsprung vibration damping control unit 53 outputs an unsprung vibration damping control command to soften the damping force characteristics of the variable damper 6 in the relative acceleration-corresponding reference state Jα0. The calculation contents of the unsprung vibration damping control unit 53 will now be described with reference to Figs. 15 and 16.

[0077] In Figures 15 and 16, when a vehicle equipped with ECU 51 is traveling in the relative acceleration-corresponding reference state Jα0, the unsprung vibration damping control unit 53 determines whether the vehicle has entered a state in which it will travel over a protrusion (and therefore whether it is traveling over a protrusion).

[0078] If it is determined that the vehicle is traveling over a protrusion, it then determines whether the vehicle is in a retraction stroke (relative acceleration<0) and whether condition A is met, where the relative acceleration is less than a predetermined threshold (hereinafter referred to as the first relative acceleration retraction threshold) Kα1 (relative acceleration<first relative acceleration retraction threshold Kα1) (in other words, whether a retraction stroke whose magnitude exceeds the first relative acceleration retraction threshold Kα1 is detected). If condition A is met, that is, if a retraction stroke whose magnitude exceeds the first relative acceleration retraction threshold Kα1 is detected, the system transitions to the first relative acceleration-based state Jα1 and starts timing using a timer (first relative acceleration timer) (the value obtained by this timing is referred to as the first timer value Tα1).

[0079] Additionally, the unsprung vibration damping control unit 53 receives an ABS / TCS / ECS operation flag as a signal from the braking / driving determination unit 31 via CAN 8. The unsprung vibration damping control unit 53 determines whether or not condition B is satisfied, that is, the ABS / TCS / ECS operation flag is turned ON and operation of any one of the ABS, TCS, or ECS is detected. If condition B is satisfied, that is, if operation of any one of the ABS, TCS, or ECS is detected, the control unit transitions to the relative acceleration corresponding third state Jα3.

[0080] If neither condition A nor condition B is satisfied (relative acceleration≧relative acceleration compression-side first threshold Kα1 and the ABS / TCS / ECS operation flag is OFF), the relative acceleration-based reference state Jα0 is maintained.

[0081] In the relative acceleration-based first state Jα1, a determination is made as to whether a condition (hereinafter referred to as the relative acceleration-based first condition) is satisfied indicating that the relative acceleration is greater than a predetermined threshold (hereinafter referred to as the relative acceleration second threshold) Kα2 determined during the extension stroke (relative acceleration > 0). If the relative acceleration-based first condition is satisfied (relative acceleration > relative acceleration second threshold Kα2), the system transitions to the relative acceleration-based second state Jα2 and starts timing (the value obtained by this timing is referred to as the second timer value Tα2) with a timer (relative acceleration second timer). On the other hand, if a condition (hereinafter referred to as the relative acceleration-based second condition) is satisfied (that the first timer value Tα1 exceeds a set time (Tα1 > set time), the system transitions to the relative acceleration-based reference state Jα0. If neither of the two conditions (relative acceleration-based first and second conditions) is satisfied (relative acceleration ≦ relative acceleration second threshold Kα2 and Tα1 ≦ set time), the system maintains the relative acceleration-based first state Jα1.

[0082] In the relative acceleration-based second state Jα2, if a condition (hereinafter referred to as a relative acceleration-based third condition) is satisfied indicating that the relative acceleration is less than a predetermined threshold (hereinafter referred to as a relative acceleration third threshold) Kα3 (in other words, a contraction stroke is detected in which the magnitude of the relative velocity corresponding to the relative acceleration exceeds the magnitude of the relative velocity threshold corresponding to the relative acceleration third threshold Kα3), the state transitions to the relative acceleration-based third state Jα3 and starts timing using a timer (relative acceleration third timer) (the value obtained by this timing is referred to as a third timer value Tα3). On the other hand, if a condition (hereinafter referred to as a relative acceleration-based fourth condition) indicating that the second timer value Tα2 has exceeded a set time is satisfied, the state transitions to the relative acceleration-based reference state Jα0. If neither of the two conditions (the relative acceleration-based third and fourth conditions) is satisfied (the relative acceleration is not less than zero and Tα2≦the set time), the relative acceleration-based second state Jα2 is maintained.

[0083] In the relative acceleration-based third state Jα3, this is the optimal timing for preventing the deterioration of sprung acceleration at the initial stage of going over the road and suppressing unsprung fluttering at the same time, so the command value is set to an optimal current command value for suppressing ground load variation. Specifically, the command values are set to the front wheel current command value (current Ifopt) and rear wheel current command value (current Iropt) used in the second embodiment. Furthermore, if condition C indicating that the third timer value Tα3 has exceeded a set time (Tα3 > set time) or condition D indicating that the ABS / TCS / ECS operation flag is OFF (hereinafter, conditions C and D are collectively referred to as the fifth relative acceleration-based condition) is satisfied, the system transitions to the relative acceleration-based reference state Jα0 and terminates control. If the fifth relative acceleration-based condition is not satisfied (Tα3 ≦ set time and the ABS / TCS / ECS operation flag is ON), the relative acceleration-based third state Jα3 is maintained, and the command value is maintained at the optimal current command value for suppressing ground load variation.

[0084] Furthermore, if condition E, which indicates that the relative acceleration has exceeded a threshold (hereinafter referred to as the fourth relative acceleration threshold) Kα4 (relative acceleration > Kα4), or condition F, which indicates that the ABS / TCS / ECS operation flag is ON (hereinafter, conditions E and F are collectively referred to as the sixth relative acceleration condition), is satisfied, the third relative acceleration timer is cleared and restarted.If the fifth relative acceleration condition and the sixth relative acceleration condition are not satisfied, the third relative acceleration state Jα3 is maintained, and the command value is maintained at the optimal current command value for suppressing ground load fluctuations.

[0085] As described above, when the first relative acceleration-related condition, which indicates that the relative acceleration is greater than the second relative acceleration threshold Kα2 (defined corresponding to the positive slope of the characteristic curve indicating the relative acceleration), and the third relative acceleration-related condition, which indicates that the relative acceleration is less than the third relative acceleration threshold Kα3 (i.e., the magnitude of the relative velocity corresponding to the relative acceleration exceeds the threshold value corresponding to the third relative acceleration threshold Kα3), is satisfied, the unsprung vibration damping control unit 53 transitions to the third relative acceleration-related state Jα3 and sets the damping force characteristics to suppress ground load fluctuations. This reduces the impact acting on the vehicle body 1 and, ultimately, on the occupant when going over a protrusion, thereby improving ride comfort and posture stability.

[0086] By controlling as described above, control starts earlier than the first reversal of the extension-to-compression stroke when going over a bump. However, because the actual switching of the damping force is delayed due to the dynamics of the ECU 51 and the variable damper 6, it is possible to switch the damping force characteristics in synchronization with the timing of the reversal of the extension-to-compression stroke by appropriately setting the value of the third relative acceleration threshold Kα3. This makes it possible to maintain the initial sprung acceleration and suppress subsequent fluttering.

[0087] Furthermore, when the ABS / TCS / ECS operation flag is turned ON, the unsprung vibration damping control unit 53 transitions to the relative acceleration corresponding third state Jα3 and sets the damping force characteristics to suppress ground contact load fluctuations. As a result, when any of the ABS, ECS, or TCS is activated, the ground contact load fluctuations can be reduced, thereby improving vehicle stability.

[0088] Thus, the third embodiment configured as described above can also achieve the same effects as the first embodiment. In the third embodiment, the ECU 51 includes an unsprung vibration damping control unit 53 for suppressing unsprung vibration. When a signal is input from the braking / driving determination unit 31, the unsprung vibration damping control unit 53 outputs an unsprung vibration damping control command as a cooperative control command value so as to reduce the ground load fluctuation on the road surface caused by the variable damper 6. Specifically, when the ABS, TCS, or ECS is activated, the unsprung vibration damping control unit 53 uses a control process to suppress unsprung vibration and outputs an optimal current command value for suppressing the ground load fluctuation as an unsprung vibration damping control command as a cooperative control command value. Therefore, when any of the ABS, TCS, or ECS is activated, the load fluctuation can be suppressed using the unsprung vibration damping control command.

[0089] In the third embodiment, when the ABS, TCS, or ECS is activated, the unsprung vibration damping control unit 53 outputs preset current command values (front wheel current command value, rear wheel current command value) as control command values for suppressing ground load variation, similar to the ABS / TCS / ECS cooperative control unit 43 according to the second embodiment. However, the present invention is not limited to this. For example, when the ABS, TCS, or ECS is activated, the unsprung vibration damping control unit 53 may output a control command value based on a target damping force that is optimal for suppressing ground load variation, similar to the ABS / TCS / ECS cooperative control unit 29 according to the first embodiment.

[0090] In the third embodiment, the unsprung vibration damping control unit 53 transitions between states based on the relative acceleration between the sprung and unsprung parts. However, the present invention is not limited to this. For example, as disclosed in Japanese Patent Application Laid-Open No. 2010-235019, the unsprung vibration damping control unit 53 may transition between states based on the relative velocity between the sprung and unsprung parts.

[0091] 1, 2, and 17 show a fourth embodiment of the present invention. The fourth embodiment is characterized in that, when a signal is input from the braking / driving determination unit, the cooperative control command priority selection unit preferentially selects a cooperative control command that reduces the variation in road load caused by the variable damper. In the fourth embodiment, the same components as those in the second embodiment are designated by the same reference numerals, and their description will be omitted.

[0092] The ECU 61 according to the fourth embodiment is configured in substantially the same manner as the ECU 41 according to the second embodiment. The ECU 61 constitutes a vehicle control device (control means) that controls the suspension device 4. The ECU 61 is a controller that controls the force generated by the variable damper 6 (force generating mechanism). As shown in FIG. 2, the ECU 61 includes a processor 62 as a control unit. The processor 62 is configured by a microcomputer or the like. The processor 62 controls the damping force of the variable damper 6 by executing a program stored in a storage unit (not shown). The input side of the ECU 61 is connected to the CAN 8, the sprung acceleration sensor 9, the unsprung acceleration sensor 10, etc., and the output side is connected to the variable damper 6, etc.

[0093] Similar to the ECU 41 of the second embodiment, the ECU 61 has a ride comfort control unit 24, a posture stability control unit 25, an ABS / TCS / ECS cooperative control unit 43, a control command selection unit 63, and a cooperative control command priority selection unit 64.

[0094] 17, the control command selection unit 63 compares the ride comfort control command with the attitude stability control command and selects the control command with the larger value. Specifically, the control command selection unit 63 selects the value on the hard side of the ride comfort control command and the attitude stability control command. At this time, the control command selection unit 63 performs the same process for the control commands for each of the four wheels.

[0095] The cooperative control command priority selection unit 64 receives the ABS / TCS / ECS operation flag as a signal from the braking / driving determination unit 31 via the CAN 8. When the ABS / TCS / ECS operation flag is OFF and no operation of the ABS, TCS, or ECS is detected, the cooperative control command priority selection unit 64 selects the control command output from the control command selection unit 63. In this case, the cooperative control command priority selection unit 64 outputs the selected control command as the final control command. At this time, a drive current based on either a ride comfort control command or an attitude stability control command is supplied to the damping force variable actuator 7 of the variable damper 6. As a result, the damping force of the variable damper 6 is controlled by the ECU 61.

[0096] On the other hand, when the ABS / TCS / ECS operation flag is turned ON and operation of any of the ABS, TCS, or ECS is detected, the cooperative control command priority selection unit 64 selects the cooperative control command output from the ABS / TCS / ECS cooperative control unit 43. At this time, a drive current based on the cooperative control command is supplied to the damping force variable actuator 7 of the variable damper 6. As a result, the damping force of the variable damper 6 is controlled by the ECU 61.

[0097] Thus, the fourth embodiment configured as above can also achieve the same effects as the first and second embodiments. Furthermore, in the fourth embodiment, the ECU 61 includes an attitude stability control unit 25 that outputs an attitude stability control command value for controlling the variable damper 6 in accordance with an inputted change in vehicle attitude, and a ride comfort control unit 24 that outputs a ride comfort control command value for controlling the variable damper 6 in accordance with an inputted sprung vibration of the vehicle. When a signal is inputted from the braking / driving determination unit 31, the ECU 61 controls the force generated by the variable damper 6, giving priority to the cooperative control command value.

[0098] Specifically, when a signal is input from the braking / driving determination unit 31 (when the ABS / TCS / ECS operation flag is ON), the cooperative control command priority selection unit 64 of the ECU 61 preferentially selects a cooperative control command that reduces the ground contact load variation on the road surface caused by the variable damper 6. Therefore, when any of the ABS, ECS, and TCS operates, the ECU 61 controls the variable damper 6 so as to reduce the ground contact load variation between the wheel 2 and the road surface caused by the force generated by the variable damper 6. As a result, when any of the ABS, ECS, and TCS operates, the ground contact load variation can be reduced, and vehicle stability can be improved, regardless of the ride comfort control command or the attitude stability control command.

[0099] In the fourth embodiment, the ABS / TCS / ECS cooperative control unit 43 switches the current command value depending on whether the ABS / TCS / ECS operation flag is ON or OFF. However, the present invention is not limited to this. The ABS / TCS / ECS cooperative control unit according to the fourth embodiment may output a current command value that is optimal for suppressing a preset ground load variation, regardless of whether the ABS / TCS / ECS operation flag is ON or OFF. Even in this case, the cooperative control command priority selection unit 64 preferentially selects and outputs the cooperative control command only when the ABS / TCS / ECS operation flag is ON.

[0100] In the fourth embodiment, the cooperative control command priority selection unit 64 and the like are applied to the second embodiment, but they may also be applied to the first and third embodiments.

[0101] In the above-described embodiments, a semi-active suspension is configured using a variable damper 6, which is an actuator (force generating mechanism). However, the present invention is not limited to this, and the actuator may configure an active suspension that generates a force in the vertical direction between the vehicle body and the wheel. Specifically, the actuator is configured using an electric actuator, a hydraulic actuator, or the like that generates a force in the expansion or contraction direction between the vehicle body and the wheel.

[0102] In the above-described embodiments, an example has been described in which the actuator (force generating mechanism) that generates an adjustable force between the vehicle body 1 and the wheel 2 is configured using a damping force adjustable variable damper 6. However, the present invention is not limited to this, and the actuator may be configured using, for example, an air suspension, a stabilizer (kinesus), an electromagnetic suspension, or the like, in addition to a hydraulic shock absorber.

[0103] In each of the above embodiments, the attitude stability control unit 25 outputs an attitude stability control command that takes into account both an anti-dive squad control command and an anti-roll control command. However, the present invention is not limited to this, and the attitude stability control unit may output an attitude stability control command that is either an anti-dive squad control command or an anti-roll control command. In other words, the attitude stability control command may be an anti-dive squad control command or an anti-roll control command. Therefore, the attitude stability control unit may be configured to omit either the anti-dive squad control unit or the anti-roll control unit.

[0104] In each of the above-described embodiments, the ECU 21, 41, 51, 61 includes the ride comfort control unit 24 and the attitude stability control unit 25. However, the present invention is not limited to this, and the ECU may omit either the ride comfort control unit or the attitude stability control unit. Alternatively, the ECU may omit both the ride comfort control unit and the attitude stability control unit and include another control unit.

[0105] In the above embodiments, the suspension system used in a four-wheeled vehicle has been described as an example. However, the present invention is not limited to this and can also be applied to, for example, two-wheeled and three-wheeled vehicles, or work vehicles and transport vehicles such as trucks and buses.

[0106] The above-described embodiments are merely examples, and partial substitution or combination of the configurations shown in different embodiments or modified examples is possible. The vehicle control system included in each of the above embodiments may have the following aspects. A vehicle control system according to a first aspect includes: a plurality of force generating mechanisms respectively provided between a body of a vehicle and four wheels, the force generating mechanisms being adjustable between soft and hard forces; and control means for variably controlling the force generated by the force generating mechanisms; The control means An unsprung vibration damping control unit outputs an unsprung vibration damping control command value for suppressing unsprung vibration based on a signal from a braking / driving determination unit that independently brakes / drives the four wheels and a signal of the relative acceleration between the vehicle body and the wheels, and adjusts the generated force of the force generating mechanism based on the unsprung vibration damping control command value so that fluctuations in the ground load on the road surface caused by the force generating mechanism are reduced. A vehicle control system according to a second aspect is the vehicle control system according to the first aspect, The control means an attitude stability control unit that outputs an attitude stability control command value for controlling the force generating mechanism in accordance with the input attitude change of the vehicle; a ride comfort control unit that outputs a ride comfort control command value for controlling the force generating mechanism in accordance with the input sprung vibration of the vehicle; a control command selection unit that outputs a control command to the force generation mechanism based on the posture stability control command value, the ride comfort control command value, and the unsprung vibration damping control command value; Equipped with. A vehicle control system according to a third aspect is the vehicle control system according to the second aspect, The control command selection unit The highest command value is selected from the input posture stability control command value, the ride comfort control command value, and the unsprung vibration damping control command value. A vehicle control system according to a fourth aspect is the vehicle control system according to the second aspect, When a signal is output from the braking / driving determination unit, the control means adjusts the generated force of the force generating mechanism based on the unsprung vibration damping control command value among the posture stability control command value, the ride comfort control command value, and the unsprung vibration damping control command value. [Explanation of symbols]

[0107] 1: vehicle body, 2: wheel, 4: suspension device, 6: variable damper (adjustable damping force shock absorber, actuator, force generating mechanism), 7: variable damping force actuator, 8: CAN, 9: sprung acceleration sensor, 10: unsprung acceleration sensor, 21, 41, 51, 61: ECU (control means, vehicle control device), 24: ride comfort control unit, 25: attitude stability control unit, 29, 43: ABS / TCS / ECS cooperative control unit, 30, 63: control command selection unit, 31: braking / driving determination unit, 53: unsprung vibration control unit, 64: cooperative control command priority selection unit

Claims

1. a plurality of force generating mechanisms respectively provided between a vehicle body and four wheels, the force generating mechanisms being adjustable between soft and hard forces; and control means for variably controlling the force generated by the force generating mechanisms; The control means an attitude stability control unit that outputs an attitude stability control command value for controlling the force generating mechanism in accordance with the input attitude change of the vehicle; a ride comfort control unit that outputs a ride comfort control command value for controlling the force generating mechanism in accordance with the input sprung vibration of the vehicle; a cooperative control command unit that outputs a cooperative control command value for controlling the force generating mechanism when a signal is input from a braking / driving determination unit that independently brakes / drives the four wheels; a control command selector that selects the highest command value among the posture stability control command value, the ride comfort control command value, and the cooperative control command value; and adjusting the force generated by the force generating mechanism based on the command value from the control command selection unit.

2. the control means includes an unsprung vibration damping control unit that outputs an unsprung vibration damping control command for suppressing unsprung vibration based on a signal from the braking / driving determination unit and a signal of a relative acceleration between the vehicle body and the wheel, 2. The vehicle control system according to claim 1, wherein when a signal is input from the braking / driving determination unit that independently brakes / drives the four wheels, the unsprung vibration damping control unit outputs the cooperative control command value so as to reduce a ground load fluctuation on the road surface caused by the force generating mechanism.

3. 3. The vehicle control system according to claim 2, wherein the control means controls the force generated by the force generating mechanism by giving priority to the cooperative control command value when a signal is input from the braking / driving determining unit.

4. A vehicle control device that controls actuators that are provided between a vehicle body and four wheels and that vary a force generated between the vehicle body and the wheels, The vehicle control device includes: an attitude stability control unit that outputs an attitude stability control command value for controlling the actuator in response to the input attitude change of the vehicle; a ride comfort control unit that outputs a ride comfort control command value for controlling the actuator in response to the input sprung vibration of the vehicle; a cooperative control command unit that outputs a cooperative control command value for controlling the generated force of the actuator when a signal is input from a braking / driving determination unit that independently brakes / drives the four wheels; a control command selector that selects the highest command value among the posture stability control command value, the ride comfort control command value, and the cooperative control command value; and controlling the actuator based on the command value from the control command selection unit.

5. the vehicle control device includes an unsprung vibration damping control unit that outputs an unsprung vibration damping control command to suppress unsprung vibration based on a signal from the braking / driving determination unit and a signal of a relative acceleration between the vehicle body and the wheel, 5. The vehicle control device according to claim 4, wherein when a signal is input from the braking / driving determination unit that independently brakes / drives the four wheels, the unsprung vibration damping control unit outputs the cooperative control command value so as to reduce a ground load fluctuation between the wheels and the road surface due to the force generated by the actuator.

6. The vehicle control device according to claim 5 , wherein when the signal is input from the braking / driving determining unit, the vehicle control device controls the actuator by giving priority to the cooperative control command value.

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