Control device

Abstract

The controller has: a weight coefficient calculation unit that, when calculating the actual target damping force on the basis of the calculation value of the vehicle behavior calculation unit, calculates a weight coefficient for bringing the actual target damping force close to a value close to a target damping force obtained in advance; an up-and-down motion calculation unit that finds a motion state in the up-and-down direction of the vehicle; a pitch motion calculation unit that finds the motion state of the vehicle in the pitch direction; an actual target damping force calculation unit that calculates the actual target damping force on the basis of the weight coefficient of the weight coefficient calculation unit and the calculation results of the vertical motion calculation unit and the pitch motion calculation unit; a target damping coefficient calculation unit that calculates a target damping coefficient on the basis of the value calculated by the actual target damping force calculation unit; a correction unit that calculates a corrected damping coefficient in which the upper limit of the target damping coefficient is reduced in a region where the sprung and unsprung relative speed of the vehicle is lower than a predetermined value; and a control signal output unit that outputs the control signal corresponding to the corrected damping coefficient to the damping force adjustment type buffer.

Description

Technical Field

[0001] The present disclosure relates to a control device for controlling a damping force adjustable shock absorber of, for example, a four-wheel vehicle. Background Art

[0002] A control device for controlling a damping force adjustable shock absorber installed between a vehicle body and a wheel is known (Patent Documents 1 and 2). The conventional control device controls the damping force of the damping force adjustable shock absorber so as to suppress the vertical vibration of the vehicle body.

[0003] Prior art literature

[0004] Patent Literature

[0005] Patent Document 1: Japanese Patent Application Publication No. 2014-69759

[0006] Patent Document 2: Japanese Patent Application Publication No. 2011-131876 Summary of the invention

[0007] Technical problem to be solved by the invention

[0008] However, the control device of the prior art performs, for example, bilinear optimal control (BLQ) in order to suppress the vibration of the vehicle body in the up-down direction. In this case, it is preferred to suppress the vibration of the pitch in addition to the vibration in the up-down direction (heave). However, in order to use BLQ to suppress the vibration of the pitch in addition to the vibration in the up-down direction, it is necessary to achieve optimization through a whole vehicle model, which has the problem of poor variability. On the other hand, in the skyhook control, there is known control using gain scheduling parameters (GSP). However, when GSP is applied to BLQ, there are two controllers, which has the problem of poor controllability.

[0009] One of the objects of the present invention is to provide a control device for a damping force adjustable shock absorber capable of suppressing vibrations in the vertical direction and in pitch while ensuring variability.

[0010] Technical solutions for solving technical problems

[0011] One embodiment of the present invention is a control device for a damping force adjustable shock absorber, which is arranged on a vehicle and can adjust the damping force generated. The control device for the damping force adjustable shock absorber comprises: a weight coefficient calculation unit, which, when calculating the actual target damping force based on the calculated value of the vehicle behavior calculation unit, calculates a weight coefficient for making the actual target damping force close to a value close to a pre-calculated target damping force; an up-and-down motion calculation unit, which calculates the motion state of the vehicle in the up-and-down direction; a pitch motion calculation unit, which calculates the motion state of the vehicle in the pitch direction; an actual target damping force calculation unit, which calculates the actual target damping force based on the weight coefficient of the weight coefficient calculation unit, the calculation results of the up-and-down motion calculation unit and the pitch motion calculation unit; a target damping coefficient calculation unit, which calculates the actual target damping force based on the actual target damping force calculation unit A calculation value is used to calculate a target damping coefficient; a correction unit is used to calculate a correction damping coefficient that reduces the upper limit of the target damping coefficient in an area where the relative speed between the sprung and unsprung parts of the vehicle is lower than a specified value; and a control signal output unit is used to output a control signal corresponding to the correction damping coefficient to the damping force adjustable shock absorber, the correction unit sets the correction damping coefficient so that the damping force increases according to the increase of the relative speed, and the slope of the damping force with respect to the relative speed decreases when the relative speed is lower than the specified value, and the slope of the damping force with respect to the relative speed increases when the relative speed is higher than the specified value, the correction unit has a maximum damping coefficient corresponding to the relative speed, and when the target damping coefficient exceeds the maximum damping coefficient, the target damping coefficient is corrected to the maximum damping coefficient.

[0012] According to one embodiment of the present invention, it is possible to suppress vibrations in the vertical direction and in the pitch direction while ensuring variability. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 1 is a diagram showing the overall configuration of a four-wheeled vehicle to which a controller according to an embodiment of the present invention is applied.

[0014] Figure 2 It is a diagram schematically showing a vehicle behavior control device according to an embodiment of the present invention.

[0015] Figure 3 1 is a control block diagram showing a controller according to the first embodiment.

[0016] Figure 4 Yes means Figure 3 Block diagram of the GSP calculation unit in .

[0017] Figure 5 Yes means Figure 3 Block diagram of the BLQ controller in FIG.

[0018] Figure 6 Yes means Figure 5 An explanatory diagram of the damping coefficient upper limit calculation section in .

[0019] Figure 7 Yes means Figure 5 An illustration of the command value calculation unit in FIG.

[0020] Figure 8 Yes means Figure 5 1 is a block diagram of a target damping force calculation unit and a correction damping coefficient calculation unit in FIG.

[0021] Fig. 9 Yes means Figure 5 Block diagram of the sprung upper and lower vibration damper BLQ.

[0022] Fig.10 Yes means Figure 5 Block diagram of the roll damper BLQ.

[0023] Fig.11 Yes means Figure 5 Block diagram of the pitch vibration reduction BLQ.

[0024] Fig.12 It is an explanatory diagram showing a vehicle model for designing the sprung vertical vibration damper BLQ.

[0025] Fig.13 It is an explanatory diagram showing a vehicle model for designing the roll damping BLQ.

[0026] Fig.14 It is an explanatory diagram showing a vehicle model for designing the pitch vibration reduction BLQ.

[0027] Fig.15 This is a characteristic diagram showing an example of time changes in the sprung displacement, the sprung acceleration, the pitch angle, the right front wheel command current, and the right rear wheel command current for the first embodiment and the comparative example.

[0028] Fig.16 1 is a control block diagram showing a controller according to the second embodiment.

[0029] Fig.17 Yes means Fig.16 Block diagram of the GSP calculation unit in .

[0030] Fig.18 1 is a control block diagram showing a controller according to the third embodiment.

[0031] Fig.19 Yes means Fig.18 Block diagram of the BLQ controller in FIG.

[0032] Fig. 20 Yes means Fig.19Block diagram of the sprung upper and lower vibration damper BLQ.

[0033] Fig.21 Yes means Fig.19 Block diagram of the roll damper BLQ.

[0034] Fig. 22 Yes means Fig.19 Block diagram of the pitch vibration reduction BLQ. DETAILED DESCRIPTION

[0035] Hereinafter, a case where the control device according to the embodiment of the present invention is applied to a four-wheel vehicle will be described in detail with reference to the attached drawings.

[0036] Figure 1 1 represents a vehicle to which a controller 11 as a control device is applied. A vehicle behavior control device 1 including the controller 11 is applied in the vehicle. Figure 2 As shown, the vehicle behavior control device 1 is composed of a suspension device 5 constituting a damping force generating device and a controller 11 constituting a vehicle control device. Figure 2 In the embodiment, the left and right front wheels and the left and right rear wheels (hereinafter collectively referred to as wheels 3) are provided at the lower side of the vehicle body 2 constituting the vehicle body. The wheels 3 are constituted by tires 4, which act as springs for absorbing the fine bumps of the road surface.

[0037] The suspension device 5 is installed between the vehicle body 2 and the vehicle wheel 3. The suspension device 5 is composed of a suspension spring 6 (hereinafter referred to as spring 6) and a damping force adjustable shock absorber (hereinafter referred to as variable damper 7) which is arranged in parallel with the spring 6 and between the vehicle body 2 and the wheel 3.

[0038] In addition, Figure 2 2 shows a case where one set of suspension devices 5 is provided between the vehicle body 2 and the wheel 3. However, the suspension devices 5 are provided independently between the four wheels 3 and the vehicle body 2, for example, and a total of four sets are provided. Figure 2 Only one group is shown schematically.

[0039] Here, the variable damper 7 of the suspension device 5 is constructed using a damping force adjustment type hydraulic shock absorber installed between the vehicle body 2 and the wheel 3. In order to continuously adjust the characteristics of the generated damping force (i.e., the damping force characteristics) from rigid characteristics (hard characteristics) to flexible characteristics (soft characteristics), a damping force variable actuator 8 composed of a damping force adjustment valve and the like is attached to the variable damper 7. The variable damper 7 constitutes a force generating mechanism that generates an adjustable force between the vehicle body 2 and the wheel 3. In addition, the damping force variable actuator 8 does not have to be a structure that continuously adjusts the damping force characteristics, and can also adjust the damping force in a multi-stage manner, for example, in more than two stages. In addition, the variable damper 7 can be a pressure control type or a flow control type. The variable damper 7 can also be a type that controls viscosity, such as a magnetorheological fluid or an electroviscous fluid.

[0040] The controller 11 constitutes a control device of the variable damper 7, and controls the damping characteristics of the variable damper 7. The controller 11 is constituted by, for example, a microcomputer. The controller 11 is connected to, for example, CAN9 (Controller Area Network), which is a communication network required for data communication. The controller 11 obtains parameters related to the driving of the vehicle through CAN9. At this time, the parameters related to the driving of the vehicle include, for example, wheel speed, slip ratio, front and rear acceleration, engine torque, brake hydraulic pressure, road friction coefficient, four-wheel independent braking drive force control flag, etc. The output side of the controller 11 is connected to the damping force variable actuator 8 of the variable damper 7.

[0041] The controller 11 also includes a storage unit 11A composed of a ROM, a RAM, a nonvolatile memory, etc. The storage unit 11A of the controller 11 stores various programs, information (vehicle information), data, etc. for controlling the variable damper 7 .

[0042] like Figure 3 As shown, the controller 11 includes a state estimating unit 12 , a GSP calculating unit 13 , and a BLQ controller 20 .

[0043] The state estimation unit 12 estimates the vehicle state (vehicle motion, vehicle behavior) using the CAN signal. That is, the state estimation unit 12 estimates the relative speed between the sprung and unsprung vehicles, the absolute vertical speed of the vehicle body (sprung speed), the relative speed between the unsprung and the road surface, the absolute vertical speed of the unsprung vehicles (unsprung speed), the roll rate, the roll angle, the pitch rate, and the pitch angle based on the signal (CAN signal) flowing through the CAN 9. For example, the state estimation unit 12 estimates the relative speed between the sprung and unsprung vehicles, the absolute vertical speed of the vehicle body, the relative speed between the unsprung and the road surface, the absolute vertical speed of the unsprung vehicles, the roll rate, the roll angle, the pitch rate, and the pitch angle based on the steering angle, the front-rear acceleration, the left-right acceleration, the yaw rate, the wheel speed of each wheel 3, the presence or absence of the brake operation, and the master cylinder hydraulic pressure of the vehicle.

[0044] In addition, regarding the vehicle model (motion equation) that models the vehicle based on the longitudinal acceleration, the left and right acceleration, the yaw rate, the wheel speed, etc., and the technology of estimating the sprung-unsprung relative speed, the absolute vertical speed of the vehicle body, the unsprung-road relative speed, the unsprung absolute vertical speed, the roll rate, the roll angle, the pitch rate, the pitch angle, etc. using a Kalman filter, etc., for example, it is recorded in various documents including Japanese Patent Application Laid-Open No. 2012-47553 (documents related to the estimation of the vehicle state), and therefore further description is omitted.

[0045] The state estimation unit 12 constitutes a vehicle behavior calculation unit that calculates the vehicle behavior. Specifically, the state estimation unit 12 includes a vertical motion calculation unit that obtains the state related to the vertical motion of the vehicle. The state estimation unit 12 includes a roll motion calculation unit that obtains the state related to the roll motion of the vehicle. The state estimation unit 12 includes a pitch motion calculation unit that obtains the state related to the pitch motion of the vehicle. The state estimation unit 12 includes a posture change detection unit that detects the posture change of the vehicle body.

[0046] The state estimation unit 12 outputs the estimated state value (motion value), that is, the signal corresponding to the relative speed between the sprung and unsprung vehicles, the absolute vertical speed of the vehicle body, the relative speed between the unsprung vehicle and the road surface, the absolute vertical speed of the unsprung vehicle, the roll rate, the roll angle, the pitch rate, the pitch angle, etc., to the BLQ controller 20.

[0047] The vehicle behavior calculation unit may be various sensors that detect sprung velocity, roll rate, pitch rate, etc. The vehicle behavior calculation unit may also estimate sprung acceleration, roll rate, pitch rate, etc. based on wheel speed and road surface information (preview) in the vehicle's traveling direction.

[0048] The GSP calculation unit 13 (gain scheduling parameter calculation unit) is a weight coefficient calculation unit that calculates a weight coefficient so that the actual target damping force based on the calculated value of the state estimation unit 12 (vehicle behavior calculation unit) approaches a value close to the target damping force obtained in advance. The GSP calculation unit 13 calculates the heave GSP and the roll GSP based on the vehicle speed obtained from the CAN 9, for example. r , Pitch GSP p The heave GSP is a weight coefficient for adjusting the heave target damping force for suppressing the vertical motion of the vehicle. r The pitch GSP is a weighting factor for adjusting the roll target damping force for suppressing the movement of the vehicle in the roll direction. p This is a weighting factor for adjusting the pitch target damping force for suppressing the movement of the vehicle in the pitch direction.

[0049] That is, when the BLQ controller 20 obtains the actual target damping force based on the calculated value of the state estimation unit 12 (vehicle behavior calculation unit), that is, the vehicle state (for example, the relative speed between the sprung and unsprung vehicles, the absolute vertical speed of the vehicle body, the relative speed between the unsprung vehicles and the road surface, the absolute vertical speed of the unsprung vehicles, the roll rate, the roll angle, the pitch rate, the pitch angle, etc.), the GSP calculation unit 13 calculates the weight coefficient (heave GSP, roll GSP) that makes the actual target damping force close to the value close to the pre-derived target damping force. r , Pitch GSP p The GSP calculation unit 13 calculates the heave GSP and the roll GSP r , Pitch GSP p Output to BLQ controller 20.

[0050] like Figure 4 As shown, the GSP calculation unit 13, for example, has a lookup table recording the relationship between the vehicle speed and the heave GSP. In this case, the heave GSP is determined by tuning in the actual vehicle test. Specifically, after the heave GSP has its general characteristics determined by sensory evaluation based on the actual vehicle test, it is fine-tuned with reference to vibration data, etc. In addition, the GSP calculation unit 13 has a lookup table recording the relationship between the vehicle speed and the roll GSP and a lookup table recording the relationship between the vehicle speed and the pitch GSP. Roll GSP r , Pitch GSP p It is also determined by tuning in actual vehicle testing, similarly to the heave GSP.

[0051] Heave GSP, roll GSP r , Pitch GSP p is a value normalized to 0 to 1. Figure 4 As shown, heave GSP, roll GSP r , Pitch GSP p It is a smaller value at low speed and a larger value at high speed. r , Pitch GSP p The present invention is not limited to this, and may be a constant value that is the same regardless of the vehicle speed.

[0052] The BLQ controller 20 calculates the command current (control signal) which becomes the command value based on the bilinear optimal control theory. Figure 5 As shown, the BLQ controller 20 includes a sprung vertical vibration damper BLQ21 , a roll vibration damper BLQ22 , a pitch vibration damper BLQ23 , a target damping force calculation unit 24 , a damping coefficient upper limit calculation unit 25 , a correction damping coefficient calculation unit 26 , and a command value calculation unit 29 .

[0053] The sprung vertical vibration damping BLQ21 is input with the vehicle state output from the state estimation unit 12 and the heave GSP output from the GSP calculation unit 13. The sprung vertical vibration damping BLQ21 calculates the heave target damping force of the variable damper 7 for reducing the vertical vibration based on the sprung-unsprung relative speed, the vehicle body absolute vertical speed, the unsprung-road relative speed, the unsprung absolute vertical speed output from the state estimation unit 12, and the heave GSP output from the GSP calculation unit 13. The sprung vertical vibration damping BLQ21 is based on, for example, Fig.12 The vehicle model shown is designed. Fig.12 In the example, a case where one set of suspension devices 5 is provided between the vehicle body 2 and the wheels 3 is illustrated. However, the suspension devices 5 may be provided in total of four sets, for example, independently between the four wheels 3 and the vehicle body 2. Fig.12 Only one group is schematically shown in FIG. As shown in the design method described later, the spring upper and lower vibration damping BLQ21 is based on Fig.12 The vehicle model is designed based on the state equations.

[0054] like Fig. 9 As shown, the sprung vertical damping BLQ21 includes a Bp calculation unit 21A, a multiplier 21B, a Bp calculation unit 21C, a multiplier 21D, a multiplier 21E, and a heave target damping force calculation unit 21F. The Bp calculation unit 21A calculates the maximum value of Bp corresponding to the relative speed based on the Bp and heave GSP calculated in advance. The multiplier 21B multiplies the maximum value of Bp output from the Bp calculation unit 21A by the relative speed. The Bp calculation unit 21C calculates the maximum value of Bp corresponding to the sprung speed based on the Bp and heave GSP calculated in advance. The multiplier 21D multiplies the maximum value of Bp output from the Bp calculation unit 21C by the sprung speed. The multiplier 21E multiplies the calculated value of the multiplier 21B by the calculated value of the multiplier 21D. The heave target damping force calculation unit 21F multiplies the calculated value of the multiplier 21E by the inverse matrix of R calculated in advance (R -1 ) to calculate the heave target damping force. In this way, the sprung up and down vibration reduction BLQ21 calculates the value obtained by multiplying the right side of the formula 12 described later by the relative speed from the left side. Thus, the sprung up and down vibration reduction BLQ21 calculates the heave target damping force obtained by multiplying the left side of the formula 12 described later by the relative speed from the left side. In addition, the case where the sprung up and down vibration reduction BLQ21 calculates the heave target damping force based on Bp corresponding to the relative speed and Bp corresponding to the sprung speed is illustrated, but the present invention is not limited to this. The sprung up and down vibration reduction BLQ21 can also calculate the heave target damping force based on Bp corresponding to other vehicle states in addition to Bp corresponding to the relative speed and the sprung speed.

[0055] The roll damping BLQ22 receives the vehicle state output from the state estimation unit 12 and the roll GSP output from the GSP calculation unit 13 as input.r The roll damping BLQ22 is based on the roll rate and roll angle output from the state estimation unit 12 and the roll GSP output from the GSP calculation unit 13. r , calculates the roll target damping force of the variable damper 7 for reducing the roll vibration. The roll vibration reduction BLQ22 is based on, for example, Fig.13 The vehicle model shown is designed. Fig.13 In the figure, the simplest 1-DOF rotational motion model is illustrated as a vehicle model that takes roll into consideration. In an actual vehicle, this motion model is provided in two groups, one on the front wheel side and the other on the rear wheel side. Fig.13 Only one group is schematically illustrated in FIG. As shown in the design method described later, the roll damping BLQ22 is based on Fig.13 The vehicle model is designed based on the state equations.

[0056] like Fig.10 As shown, the roll damping BLQ22 includes a Bp calculation unit 22A, a multiplier 22B, and a roll target damping force calculation unit 22C. The Bp calculation unit 22A calculates the roll target damping force based on the previously determined Bp. roll p roll and roll GSP r , find the B corresponding to the roll rate roll p roll The multiplier 22B obtains the maximum value of Bp output from the Bp calculation unit 22A. roll p roll The roll target damping force calculation unit 22C multiplies the calculated value of the multiplier 22B by the previously calculated R roll The inverse matrix (R roll -1 ) to calculate the roll target damping force. In this way, the roll damping BLQ22 calculates the value obtained by multiplying the right side of the equation 20 described later by the relative speed from the left side. Thus, the roll damping BLQ22 calculates the roll target damping force obtained by multiplying the left side of the equation 20 described later by the roll rate from the left side.

[0057] The pitch vibration reduction BLQ23 receives the vehicle state output from the state estimation unit 12 and the pitch GSP output from the GSP calculation unit 13 as input. p The pitch vibration reduction BLQ23 calculates the pitch GSP output from the GSP calculation unit 13 based on the pitch rate and pitch angle output from the state estimation unit 12. p , calculate the pitch target damping force of the variable damper 7 for reducing pitch vibration. The pitch vibration reduction BLQ23 is based on, for example, Fig.14 The vehicle model shown is designed. Fig.14 In the figure, the simplest 1-DOF rotational motion model is illustrated as a vehicle model that takes pitch into consideration. In an actual vehicle, this motion model is set up in two groups on the left and right sides. Fig.14 As shown in the design method described later, the pitch vibration reduction BLQ23 is based on Fig.14 The vehicle model is designed based on the state equations.

[0058] like Fig.11 As shown, the pitch vibration reduction BLQ23 includes a Bp calculation unit 23A, a multiplier 23B, and a pitch target damping force calculation unit 23C. The Bp calculation unit 23A calculates the pitch vibration reduction BLQ23 based on the previously calculated Bp. pitch p pitch and pitch GSP p , find the B corresponding to the pitch rate pitch p pitch The multiplier 23B obtains the maximum value of Bp output from the Bp calculation unit 23A. pitch p pitch The pitch target damping force calculation unit 23C multiplies the calculated value of the multiplier 23B by the R calculated in advance. pitch The inverse matrix (R pitch -1 ) is multiplied to calculate the pitch target damping force. In this way, the pitch vibration reduction BLQ23 calculates the value obtained by multiplying the right side of the equation 27 described later by the relative speed from the left side. Thus, the pitch vibration reduction BLQ23 calculates the pitch target damping force obtained by multiplying the left side of the equation 27 described later by the pitch rate from the left side.

[0059] The target damping force calculation unit 24 calculates the actual target damping force of each variable damper 7 based on the three target damping forces (heave target damping force, roll target damping force, pitch target damping force) output from the sprung vertical vibration damping BLQ21, the roll vibration damping BLQ22, and the pitch vibration damping BLQ23 (see Figure 5 The sprung vertical vibration reduction BLQ21, the pitch vibration reduction BLQ23, and the target damping force calculation unit 24 constitute the heave GSP and roll GSP calculated by the GSP calculation unit 13 (weight coefficient calculation unit). r , Pitch GSP p The actual target damping force calculation unit calculates the actual target damping force based on the (weight coefficient) and the calculation results of the state estimation unit 12 (the vertical motion calculation unit, the pitch motion calculation unit).

[0060] like Figure 8 As shown, the target damping force calculation unit 24 includes an adder 24A and a damping force dead zone calculation unit 24B. The adder 24A adds the heave target damping force from the sprung vertical vibration damper BLQ21, the roll target damping force from the roll vibration damper BLQ22, and the pitch target damping force from the pitch vibration damper BLQ23, and calculates the BLQ target damping force obtained by adding them.

[0061] The damping force dead zone calculation unit 24B sets a dead zone for the BLQ target damping force output from the adder 24A. The damping force dead zone calculation unit 24B outputs the actual target damping force set as the dead zone of the BLQ target damping force.

[0062] The bilinear optimal control (BLQ) controls the vehicle even at a small road input, so a high damping force is generated for a small road input, which may deteriorate the ride comfort. Therefore, an insensitive band is set for the BLQ target damping force in the damping force insensitive band calculation unit 24B. Thus, the damping force insensitive band calculation unit 24B makes the control ineffective for a small target damping force.

[0063] When the control gain of BLQ varies according to the vehicle speed, the dead zone is also set according to the vehicle speed in the dead zone selection process. When the control gain of BLQ varies according to the vehicle mode, the dead zone is also set according to the vehicle mode in the dead zone selection process.

[0064] When the vehicle is traveling on a bumpy road, the target damping force becomes smaller when the sprung speed and relative displacement cross 0. At this time, if the damping force insensitive zone is set, the control amount is not output, and the vibration reduction performance deteriorates. Therefore, when traveling on a bumpy road, in order to give priority to the vibration reduction performance, the provisional BLQ damping force insensitive zone is subjected to a relaxation process of reducing the insensitive zone when the bumpy road index is high, so that the control amount is output even with a smaller target damping force. In addition, in order to improve the tunability, the insensitive zone relaxation process may be switched between effective and ineffective.

[0065] The target damping force calculation unit 24 adds the heave target damping force, the roll target damping force, and the pitch target damping force, but the present invention is not limited thereto. The target damping force calculation unit 24 may select the maximum value among the heave target damping force, the roll target damping force, and the pitch target damping force, for example.

[0066] The damping coefficient upper limit calculation unit 25 calculates the maximum damping coefficient Cmax which is the upper limit value of the damping coefficient C. Figure 6 As shown, the damping coefficient upper limit calculation unit 25 is a maximum damping coefficient map for calculating the maximum damping coefficient Cmax based on the vehicle state. The damping coefficient upper limit calculation unit 25 includes, for example, a relative speed x between the sprung and unsprung parts. * The damping coefficient upper limit calculation unit 25 calculates the relationship between the relative speed x and the maximum damping coefficient Cmax. * The maximum damping coefficient Cmax is output. At this time, the maximum damping coefficient Cmax is set to a value within a range that does not exceed the maximum value of the damping coefficient that the variable damper 7 can generate. The maximum damping coefficient Cmax is *When the relative speed x is lower than the specified threshold value Vt, a smaller value is set. * When the relative speed is higher than the threshold value Vt, a larger value is set.

[0067] Specifically, when the relative speed x * is lower than the threshold value Vt (-Vt < x * < Vt), the maximum damping coefficient Cmax is set to a smaller low-speed setting value C1. On the other hand, when the relative speed x on the extension side (positive side) * is higher than the threshold value Vt (x * > Vt), the maximum damping coefficient Cmax is set to a high-speed setting value C2 that is larger than the low-speed setting value C1. Similarly, when the relative speed x on the contraction side (negative side) * is higher than the threshold value Vt (x * < -Vt), the maximum damping coefficient Cmax is set to a high-speed setting value C3 that is larger than the low-speed setting value C1.

[0068] When the relative speed x * becomes a value close to the threshold value Vt, the maximum damping coefficient Cmax can also be set to a value between the low-speed setting value C1 and the high-speed setting value C2. Similarly, when the relative speed x * becomes a value close to the threshold value (-Vt), the maximum damping coefficient Cmax can also be set to a value between the low-speed setting value C1 and the high-speed setting value C3.

[0069] The high-speed setting values C2 and C3 are appropriately set in consideration of the structure, specifications, damping force characteristics, etc. of the variable damper 7. In addition, the case where the low-speed setting value C1 and the high-speed setting values C2 and C3 are all constant values is illustrated, but it can also be configured to vary according to the relative speed x * as well.

[0070] In addition, the threshold value Vt is, for example, a value obtained through experiments in consideration of the generation situation of jerk, and is appropriately set according to the structure, damping force characteristics, etc. of the variable damper 7. In addition, the threshold value Vt can be set to the same value on the positive side and the negative side of the relative speed x * , or can be set to different values on the positive side and the negative side of the relative speed x * .

[0071] The correction damping coefficient calculation unit 26 calculates a target damping coefficient C corresponding to the actual target damping force, and outputs a correction damping coefficient Ca based on the target damping coefficient C and the maximum damping coefficient Cmax (refer to Figure 8 ). The correction damping coefficient calculation unit 26 includes a target damping coefficient calculation unit 27 and a minimum value selection unit 28.

[0072] The target damping coefficient calculation unit 27 is a target damping coefficient calculation unit that calculates the target damping coefficient C based on the calculated value of the actual target damping force calculation unit. The target damping coefficient calculation unit 27 calculates the target damping coefficient C corresponding to the actual target damping force output from the target damping force calculation unit 24. Specifically, the target damping coefficient calculation unit 27 is composed of a divider that divides the actual target damping force by the relative speed x. * To calculate the target damping coefficient C.

[0073] The minimum value selection unit 28 compares the target damping coefficient C output from the target damping coefficient calculation unit 27 and the maximum damping coefficient Cmax output from the damping coefficient upper limit calculation unit 25, selects the smaller value of these coefficients C and Cmax, and outputs it as the correction damping coefficient Ca. Therefore, the minimum value selection unit 28 and the damping coefficient upper limit calculation unit 25 constitute a relative speed x between the sprung and unsprung parts of the vehicle. * The correction unit calculates the correction damping coefficient Ca which lowers the upper limit of the target damping coefficient C in the low speed region.

[0074] At this time, the correction unit sets the correction damping coefficient Ca so that the damping force is adjusted according to the relative speed x * becomes larger with the increase of the relative speed x * is the damping force at low speed relative to the relative speed x * The slope becomes smaller at the relative speed x * is the damping force relative to the relative speed x at high speed * The slope of the correction part becomes larger. In addition, the correction part has * The corresponding maximum damping coefficient Cmax, when the target damping coefficient C exceeds the maximum damping coefficient Cmax, the target damping coefficient C is corrected to the maximum damping coefficient Cmax.

[0075] The command value calculation unit 29 constitutes a control signal output unit that outputs a control signal corresponding to the corrected damping coefficient Ca to the variable damper 7 (damping force adjustment type shock absorber). The command value calculation unit 29 outputs a command current value I as a control signal corresponding to the corrected damping coefficient Ca. Figure 7 As shown, the command value calculation unit 29 calculates the value according to the relative speed x * A damping coefficient map is provided to variably set the relationship between the correction damping coefficient Ca and the command current value I. The damping coefficient map is prepared based on the experimental data of the inventors. Then, the command value calculation unit 29 calculates the relationship between the correction damping coefficient Ca and the relative speed x * , determine a command current value I for adjusting the damping force characteristics of the variable damper 7 , and output the command current value I to the damping force variable actuator 8 of the variable damper 7 .

[0076] In addition, the command value calculation unit 29 outputs a control signal (command current value I) for controlling the variable damper 7 so that the damping force adjustable shock absorber conforms to the skyhook theory, for example. The command value calculation unit 29 has Figure 7 The characteristic line 29A on the rigid side shown by the solid line and Figure 7 The characteristic line 29B on the flexible side is shown by the middle dotted line. At this time, the characteristic line 29A on the rigid side is arranged in a range where the corrected damping coefficient Ca is larger than the characteristic line 29B on the flexible side.

[0077] Furthermore, if the input relative speed x * and the correction damping coefficient Ca, then the correction damping coefficient Ca and the relative speed x are obtained in the damping coefficient map of the command value calculation unit 29. * When the intersection is arranged in a range where the corrected damping coefficient Ca is larger than the characteristic line 29A on the rigid side, the command current value I is increased and the damping force characteristic is set to a rigid characteristic. On the other hand, when the intersection is arranged in a range where the corrected damping coefficient Ca is smaller than the characteristic line 29B on the flexible side, the command current value I is reduced and the damping force characteristic is set to a flexible characteristic. Furthermore, when the intersection is arranged in a range between the characteristic line 29A on the rigid side and the characteristic line 29B on the flexible side, the command current value I is adjusted according to the corrected damping coefficient Ca, and the damping force characteristic is set to a characteristic between rigidity and flexibility.

[0078] According to the above, the damping force generated by the variable damper 7 is variably adjusted between the rigid state and the flexible state continuously or in multiple stages according to the command current value I supplied to the damping force variable actuator 8 .

[0079] Next, a design method of the sprung vertical vibration damper BLQ21 , the roll vibration damper BLQ22 , and the pitch vibration damper BLQ23 will be described, and their tuning using a gain scheduling parameter (GSP) will be described.

[0080] (1) Design of the up-and-down motion control system (sprung up-and-down vibration damping BLQ21)

[0081] Fig.12 The control design model (1 / 4 vehicle model) with vertical motion as the object is shown. Here, the absolute vertical displacement of the vehicle body 2 (on the sprung spring) is set to z b , the absolute vertical displacement under the spring is set to z t , the absolute vertical displacement of the road is set to z0, and the sprung mass (body mass) is set to m b , the unsprung mass m t , the spring constant between the vehicle body 2 and the unsprung spring (between the sprung and the unsprung spring) is set to k s , set the tire spring constant to k t, the damper damping coefficient is c, and the control force acting between the sprung and unsprung is f. In addition, it is considered that the control force f also acts in addition to the flexible damping force characteristic, and the damper damping coefficient c sets the damping coefficient of the flexible damping force characteristic.

[0082] At this time, if the relative displacement between the sprung and unsprung is set to z bt , the relative displacement between the unsprung and the road surface is set as z t0 , then the relative displacement z bt 、z t0 The state equations are shown in equations 1 to 3 below. In the state equations, the state variable x and the output y are shown in equations 4 and 5. The dot in the equation refers to the first-order differential (d / dt) based on time t. If there are two points, it refers to the second-order differential (d2 / dt2).

[0083] [Formula 1]

[0084]

[0085] [Formula 2]

[0086]

[0087] [Formula 3]

[0088]

[0089] [Formula 4]

[0090]

[0091] [Formula 5]

[0092]

[0093] In addition, the external force u acting between the vehicle body 2 and the unsprung load is set as the control force f (u=f), and the disturbance w is set as the detected road surface displacement z0 (w=z0). In addition, the elements of the state equation are shown in Formula 6.

[0094] [Formula 6]

[0095]

[0096] Based on the above state equation, the design method of the up-and-down motion control system (sprung up-and-down vibration damping BLQ21) based on the bilinear optimal control theory is explained. Although the control force f is used in the above state equation, in the case of the bilinear system, the input is the damping coefficient u c Therefore, equation (3) is expressed as the following state equation.

[0097] [Formula 7]

[0098]

[0099] Here, x * is a matrix containing the state variables x, so if we input u with the damping coefficient c and relative speed represent the control force f, as shown in Equation 8. At this time, x * As shown in formula 9.

[0100] [Formula 8]

[0101]

[0102] [Formula 9]

[0103]

[0104] Generally, when the input is irregular, the state variable becomes a probability variable, so the evaluation function uses the formula 10 represented by the expected value. Among them, the state quantity (relative displacement between sprung and unsprung, sprung speed, relative displacement between unsprung and road surface, unsprung speed) is used in the evaluation function. In addition, C T QC is the weight matrix for the output, and R is the weight matrix for the input.

[0105] [Formula 10]

[0106]

[0107] Here, find the optimal control input u that satisfies Equation 11 c 0 If the above problem is solved by dynamic programming, the optimal control input u c 0 is considered to be a stable problem, then the optimal control input u c 0 Calculate it as in formula 12.

[0108] [Formula 11]

[0109]

[0110] [Formula 12]

[0111]

[0112] Among them, p in equation 12 is the only positive definite solution of equation 13.

[0113] [Formula 13]

[0114]

[0115] Here, Q and R of the sprung upper and lower vibration damper BLQ21 are set to the values ​​shown in Formula 14, and p is calculated.

[0116] [Formula 14]

[0117]

[0118] (2) Design of the roll motion control system (roll damping BLQ22)

[0119] Similar to the control system for the up and down motion described above, the roll damping BLQ22 is designed based on the bilinear control theory. The motion model is Fig.13 The simplest 1-DOF rotational motion model is shown as a vehicle model taking roll into consideration.

[0120] Here, the roll angle of the vehicle body is denoted as θ, and the absolute vertical displacements of the left and right wheels on the road surface are denoted as x and 0l 、x 0r , the body roll inertia is set as I, the spring constant between the sprung and unsprung is set as k s , set the spring constant of the stabilizer to k st , let the damping coefficient of the damper be c, let the external force acting on the left and right wheels between the sprung and unsprung wheels be F r 、F l .according to Fig.13 , the equation of motion in the roll direction is derived as in Equation 15.

[0121] [Formula 15]

[0122]

[0123] Since it is a bilinear system, the state equation is shown in Equation 16.

[0124] [Formula 16]

[0125]

[0126] Here, since it is a bilinear system, if the damping coefficients of the left and right wheels are used as input c r 、c l and relative velocity represent external force, as shown in Formula 17.

[0127] [Formula 17]

[0128]

[0129] In addition, the state variable x roll 、x * roll , control power croll , and interference w rollAs shown in Formula 18 respectively.

[0130] [Formula 18]

[0131]

[0132] At this time, the elements of the state equation are as shown in Formula 19.

[0133] [Formula 19]

[0134]

[0135] According to this state equation, the optimal control input u is obtained in the same way as the control system of the vertical vibration. 0 c roll , then it becomes equation (20).

[0136] [Formula 20]

[0137]

[0138] Among them, p in formula 20 roll is the only positive definite solution to equation 21.

[0139] [Formula 21]

[0140]

[0141] Here, the Q of the roll damping BLQ22 roll and R roll Set the values ​​shown in Formula 22 respectively and calculate p roll .

[0142] [Formula 22]

[0143]

[0144] (3) Design of pitch motion control system (pitch vibration reduction BLQ23)

[0145] The pitch vibration reduction BLQ23 is designed based on the bilinear control theory in the same way as the control systems for the up-and-down motion and the roll motion described above. The motion model is Fig.14 The figure shown is the simplest 1-DOF rotational motion model of a vehicle model taking pitch into account.

[0146] Here, the vertical force applied to the vehicle body by the front and rear suspensions is defined as F Fr 、F Rr , set the front and rear spring constants to k Fr , k Rr , the front and rear drag coefficients are set to c Fr 、c RrSet the horizontal distance from the center of gravity to the front and rear suspensions as L Fr , L Rr , set the pitch angle to Φ, and the front and rear vehicle height displacements to x 2Fr 、x 2Rr , set the front and rear road heights to x 0Fr 、x 0Rr , the up and down forces generated by the front and rear actuators are set to F FrAct 、F RrAct , the inertia moment of the spring in the pitch direction around the 1 / 2 center of gravity is set to I yy .according to Fig.14 , the equation of motion in the roll direction is derived as in Equation 23.

[0147] [Formula 23]

[0148]

[0149] Here, since it is a bilinear system, the state equation is as shown in Equation 24.

[0150] [Formula 24]

[0151]

[0152] In addition, the state variable x pitch 、x * pitch , control power pitch , and interference w pitch Let them be 25 respectively.

[0153] [Formula 25]

[0154]

[0155] At this time, the elements of the state equation are as shown in Formula 26.

[0156] [Formula 26]

[0157]

[0158] According to this state equation, the optimal control input u is obtained in the same way as the control system of the vertical vibration. 0 c pitch , then it becomes equation (27).

[0159] [Formula 27]

[0160]

[0161] Among them, p in formula 27 pitch is the only positive definite solution to equation 28.

[0162] [Formula 28]

[0163]

[0164] Here, the Q of the pitch vibration reduction BLQ23 pitch and R pitch Set the values ​​shown in Formula 29 respectively and calculate p pitch .

[0165] [Formula 29]

[0166]

[0167] (4) Tuning using gain scheduling parameters

[0168] The optimal control inputs for the control systems of vertical vibration, roll vibration, and pitch vibration are expressed by the following equations 11, 20, and 27. At this time, B is obtained by calculation in advance. T p、B roll T p roll , B pitch T p pitch The theoretical maximum value (maximum value of the control amount) and minimum value (minimum value of the control amount) of roll T p roll , B pitch T p pitch An example of the maximum and minimum values ​​of B. T Similarly, p can also be obtained in advance by calculation.

[0169] [Formula 30]

[0170]

[0171] [Formula 31]

[0172]

[0173] Use parameters (heave GSP, roll GSP r , Pitch GSP p ) Linearly interpolate the value between the maximum value and the longest value and select an arbitrary control amount. Based on the use of heave GSP, roll GSP r , Pitch GSP p The target damping forces for the vertical vibration reduction, the roll vibration reduction, and the pitch vibration reduction can be obtained by using the obtained control amount and equations 11, 20, and 27.

[0174] When tuning BLQ without using gain scheduling parameters, it is necessary to change Q, R, Q roll , R roll , Q pitch , R pitch and solve the Riccati equation again each time. In contrast, when using gain scheduling parameters (heave GSP, roll GSP r , Pitch GSP p ) is used to tune the BLQ, there is no need to solve the Riccati equation again, and tuning can be performed with less man-hours.

[0175] The vehicle behavior control device 1 according to the first embodiment has the above-described configuration. Next, a process of variably controlling the damping force characteristics of the variable damper 7 using the controller 11 will be described.

[0176] When the vehicle is running, parameters related to the running of the vehicle are input to the controller 11 via the CAN 9. The state estimation unit 12 of the controller 11 estimates the sprung-unsprung relative speed, the vehicle body absolute vertical speed (sprung speed), the unsprung-road relative speed, the unsprung absolute vertical speed (unsprung speed), the roll rate, the roll angle, the pitch rate, the pitch angle, etc., which are the vehicle states, based on the CAN signal.

[0177] At this time, the vehicle state calculated by the state estimation unit 12 and the heave GSP and roll GSP calculated by the GSP calculation unit 13 are input to the BLQ controller 20 of the controller 11. r , Pitch GSP p The sprung up-and-down vibration reduction BLQ21 of the BLQ controller 20 calculates the heave target damping force based on the vehicle state and the heave GSP. The roll vibration reduction BLQ22 of the BLQ controller 20 calculates the heave target damping force based on the vehicle state and the roll GSP. r The roll target damping force is calculated. The pitch damping BLQ23 of the BLQ controller 20 is based on the vehicle state and the pitch GSP p Calculate the heave target damping force.

[0178] The target damping force calculation unit 24 of the BLQ controller 20 calculates the actual target damping force based on the heave target damping force, the roll target damping force, and the pitch target damping force. The target damping coefficient calculation unit 27 of the BLQ controller 20 divides the actual target damping force by the relative speed x * The target damping coefficient C is calculated. The minimum value selection unit 28 of the BLQ controller 20 selects the smaller value of the target damping coefficient C output from the target damping coefficient calculation unit 27 and the maximum damping coefficient Cmax output from the damping coefficient upper limit calculation unit 25, and outputs it as the correction damping coefficient Ca. The command value calculation unit 29 of the BLQ controller 20 calculates the correction damping coefficient Ca and the relative speed x *The corresponding command current value I.

[0179] Then, the command current value I is input to the damping force variable actuator 8 of the variable damper 7, and the driving of the damping force variable actuator 8 is controlled. As a result, the damping force characteristics of the variable damper 7 are continuously controlled so as to be variable between the rigidity characteristic (hard characteristic) and the flexibility characteristic (soft characteristic).

[0180] In particular, the controller 11 of the first embodiment includes the pitch vibration reduction BLQ23 and calculates the command current value I based on the pitch target damping force calculated by the pitch vibration reduction BLQ23. Therefore, the pitch vibration can be suppressed compared to the case where the pitch vibration reduction BLQ23 is omitted.

[0181] In order to confirm the pitch vibration improvement effect of the present embodiment, a real vehicle test was conducted on the first embodiment and the comparative example while the vehicle was traveling on a rough road. The results are shown in FIG. Fig.15 In addition, in the actual vehicle test, the vehicle speed was set to 100km / h, the heave GSP was set to 0.6, and the pitch GSP was set to p Set to 0.3.

[0182] exist Fig.15 In , the solid line represents the characteristics of the first embodiment. However, in this case, the controller 11 sets the gain of the roll target damping force to 0 when calculating the roll target damping force. That is, Fig.15 The solid line in represents the characteristic when the roll damping BLQ22 is omitted from the controller 11 of the first embodiment. Fig.15 In FIG. 1 , the dotted line indicates the characteristics of the comparative example (prior art). In this case, the comparative example corresponds to the case where the controller of Patent Document 1 is used. That is, in the comparative example, the variable damper 7 is controlled based on the target damping force that only suppresses the up-and-down vibration of the spring. Fig.15 As shown, it can be seen that in the first embodiment, the amplitude of the pitch angle is reduced compared to the comparative example, and for example, the pitch vibration is improved (reduced) by about 7.3%.

[0183] Thus, the controller 11 as the control device of the present embodiment includes a weight coefficient calculation unit (GSP calculation unit 13) for calculating a weight coefficient (heave GSP, pitch GSP) for making the actual target damping force based on the calculated value of the vehicle behavior calculation unit (state estimation unit 12) approach a value close to the target damping force obtained in advance. p); a vertical motion calculation unit (state estimation unit 12) that obtains a state related to the vertical motion of the vehicle; a pitch motion calculation unit (state estimation unit 12) that obtains a state related to the pitch motion of the vehicle; an actual target damping force calculation unit (sprung vertical vibration reduction BLQ21, pitch vibration reduction BLQ23, target damping force calculation unit 24) that calculates the actual target damping force based on the weight coefficient of the weight coefficient calculation unit and the calculation results of the vertical motion calculation unit and the pitch motion calculation unit;

[0184] A target damping coefficient calculation unit (target damping coefficient calculation unit 27) calculates a target damping coefficient based on the calculated value of the actual target damping force calculation unit; a correction unit (minimum value selection unit 28) calculates the target damping coefficient based on the calculated value of the actual target damping force calculation unit; and a correction unit (minimum value selection unit 28) calculates the target damping coefficient based on the relative speed x between the sprung and unsprung parts of the vehicle. * a correction damping coefficient Ca which lowers the upper limit of the target damping coefficient C for a low-speed region; and a control signal output unit (command value calculation unit 29) which outputs a control signal corresponding to the correction damping coefficient Ca to the damping force adjustable shock absorber (variable damper 7).

[0185] At this time, the weight coefficient calculation unit (GSP calculation unit 13) calculates the heave GSP related to the vertical motion of the vehicle and the pitch GSP related to the pitch motion of the vehicle. p The actual target damping force calculation unit includes, as weight coefficients, a heave BLQ (sprung vertical damping BLQ21) for calculating the target damping force in the vertical direction of the vehicle based on the heave GSP and the calculation result of the vertical motion calculation unit and a pitch GSP based on the pitch GSP. p The pitch BLQ (pitch vibration reduction BLQ23) of the target damping force in the pitch direction of the vehicle is calculated based on the calculation result of the pitch motion calculation unit, and the actual target damping force is calculated based on the target damping force (heaving target damping force) calculated by the heave BLQ and the target damping force (pitch target damping force) calculated by the pitch BLQ.

[0186] Therefore, the controller 11 can control the damping force of the variable damper 7 based on the heave target damping force for suppressing the vertical vibration on the sprung and the pitch target damping force for suppressing the pitch vibration. As a result, both the vertical vibration on the sprung and the pitch vibration can be reduced. In addition, the controller 11 controls the damping force of the variable damper 7 based on the weight coefficients (heave GSP, pitch GSP p ) and vehicle status (relative speed between sprung and unsprung, absolute vertical speed of the vehicle body (sprung speed), relative speed between unsprung and road surface, absolute vertical speed of unsprung (unsprung speed), pitch rate, pitch angle), calculate the actual target damping force. Therefore, there is no need to solve the Riccati equation again, and by adjusting the weight coefficients (heave GSP, pitch GSP p), it is possible to reduce tuning parameters and easily tune the controller 11 (sprung vertical vibration reduction BLQ21, pitch vibration reduction BLQ23).

[0187] In addition, the correction unit (minimum value selection unit 28) of the controller 11 sets the correction damping coefficient Ca so as to be equal to the relative speed x * As the relative speed x increases, the damping force increases, and * is the damping force at low speed relative to the relative speed x * The slope becomes smaller at the relative speed x * When the speed is high, the slope of the damping force relative to the relative speed becomes larger, and the correction part has a relative speed x * The corresponding maximum damping coefficient Cmax, when the target damping coefficient C exceeds the maximum damping coefficient Cmax, outputs a corrected damping coefficient Ca after correcting the target damping coefficient C to the maximum damping coefficient Cmax.

[0188] Therefore, when the variable damper 7 performs stroke reversal between the extension stroke and the contraction stroke, the relative speed x * At low speed, the controller 11 outputs a correction damping coefficient Ca that lowers the upper limit of the target damping coefficient C, and outputs a command current value I corresponding to the correction damping coefficient Ca to the variable damper 7. This can reduce the generation of abnormal noise and jerk caused by a sudden change in damping force.

[0189] On the other hand, the controller 11 is at a relative speed x * At high speed, the correction damping coefficient Ca is calculated to increase the upper limit of the target damping coefficient C compared to the low speed. In this case, when the variable damper 7 is in the middle of the extension stroke and the contraction stroke, the relative speed x * At high speed, the correction damping coefficient Ca can be calculated with a larger value without limiting the target damping coefficient C as much as possible. As a result, at the relative speed x * At high speeds, a large damping force can be generated by the variable damper 7 to ensure vibration damping performance, thereby improving riding comfort.

[0190] The controller 11 further includes a posture change detection unit (state estimation unit 12 ) for detecting a posture change of the vehicle body 2 . When the correction unit (minimum value selection unit 28 ) determines that a posture change has occurred based on a detection result of the posture change detection unit, the correction unit decreases the correction amount.

[0191] At this time, when the posture change of the vehicle body 2 does not occur, the correction unit increases the correction amount and reduces the upper limit of the target damping coefficient when the relative speed is low. Thus, it is possible to suppress a sharp change in the damping force. On the other hand, when the posture change of the vehicle body occurs, the correction unit reduces the correction amount to relax the upper limit of the target damping coefficient. Thus, it is possible to generate a damping force that resists the posture change of the vehicle body and ensure vibration reduction performance.

[0192] The controller 11 further includes a roll motion calculation unit (state estimation unit 12) for obtaining a state related to the motion in the roll direction of the vehicle. In this case, the weight coefficient calculation unit (GSP calculation unit 13) calculates the heave GSP related to the motion in the up-down direction of the vehicle and the roll GSP related to the motion in the roll direction of the vehicle. r , pitch GSP related to the pitch direction movement of the vehicle p As the weight coefficient, the actual target damping force calculation unit includes a heave BLQ (sprung vertical damping BLQ21) for calculating the target damping force in the vertical direction of the vehicle based on the heave GSP and the calculation result of the vertical motion calculation unit, and a heave BLQ (sprung vertical damping BLQ21) for calculating the target damping force in the vertical direction of the vehicle based on the roll GSP. r The roll BLQ (roll damping BLQ22) of the target damping force in the roll direction of the vehicle is calculated based on the calculation result of the roll motion calculation unit, and the pitch GSP p The pitch BLQ (pitch vibration reduction BLQ23) of the target damping force in the pitch direction of the vehicle is calculated based on the calculation result of the pitch motion calculation unit, and the actual target damping force is calculated based on the target damping force (heave target damping force) calculated by the heave BLQ, the target damping force (roll target damping force) calculated by the roll BLQ, and the target damping force (pitch target damping force) calculated by the pitch BLQ.

[0193] Therefore, the actual target damping force calculation unit (sprung vertical vibration damping BLQ21, roll vibration damping BLQ22, pitch vibration damping BLQ23, target damping force calculation unit 24) can calculate the actual target damping force based on the calculation result of the roll motion calculation unit in addition to the calculation results of the vertical motion calculation unit and the pitch motion calculation unit. That is, the controller 11 can control the damping force of the variable damper 7 based on the roll target damping force for suppressing the roll vibration in addition to the heave target damping force for suppressing the sprung vertical vibration and the pitch target damping force for suppressing the pitch vibration. As a result, in addition to the sprung vertical vibration and the pitch vibration, the roll vibration can also be reduced.

[0194] In the first embodiment, the controller 11 calculates the weight coefficients (heave GSP, roll GSP r , Pitch GSP p) and vehicle status (relative speed between sprung and unsprung, absolute vertical speed of the vehicle body (sprung speed), relative speed between unsprung and road surface, absolute vertical speed of unsprung (unsprung speed), roll rate, roll angle, pitch rate, pitch angle) to calculate the actual target damping force. Therefore, there is no need to solve the Riccati equation again, and by adjusting the weight coefficients (heave GSP, roll GSP r , Pitch GSP p ), it is possible to reduce tuning parameters and easily tune the controller 11 (sprung vertical vibration reduction BLQ21, roll vibration reduction BLQ22, pitch vibration reduction BLQ23).

[0195] then, Figure 1 , Figure 2 , Fig.16 and Fig.17 The second embodiment is characterized in that the weight coefficient calculation unit changes the coefficient according to the state of the road surface, the weight of the vehicle and the selected damping force mode. In the second embodiment, the same components as those in the first embodiment are denoted by the same reference numerals and their description is omitted.

[0196] The controller 31 of the second embodiment constitutes a control device for the variable damper 7, and controls the damping characteristics of the variable damper 7 (see Figure 1 , Figure 2 ). The controller 31 is configured in substantially the same manner as the controller 11 of the first embodiment. The controller 31 is, for example, a microcomputer and is connected to the CAN 9. The controller 31 obtains parameters related to the driving of the vehicle through the CAN 9. The output side of the controller 31 is connected to the damping force variable actuator 8 of the variable damper 7.

[0197] The controller 31 also includes a storage unit 31A composed of a ROM, a RAM, a nonvolatile memory, etc. The storage unit 31A of the controller 31 stores various programs, information (vehicle information), data, etc. for controlling the variable damper 7 .

[0198] like Fig.16 As shown, the controller 31 includes the state estimating unit 12, the GSP calculating unit 34, and the BLQ controller 20. In addition, the controller 31 includes a road surface index calculating unit 32 and a weight estimating unit 33.

[0199] The road surface index calculation unit 32 obtains the sprung speed and the like from the state estimation unit 12, and uses them to output the road surface index. The road surface index calculation unit 32 estimates the vertical acceleration of the vehicle body 2 (on the sprung body) based on the sprung speed and the like. The road surface index calculation unit 32 is provided with, for example, a bandpass filter, etc., and extracts the undulating road component of a predetermined frequency band (for example, 0.5 to 2 Hz) from the sprung vertical acceleration. The road surface index calculation unit 32 outputs the road surface index (undulating road index) corresponding to the magnitude of the undulating road component (undulating road level) to the GSP calculation unit 34. At this time, when the undulating road component is not extracted and becomes the minimum value, the road surface index corresponding to the undulating road becomes 0. On the other hand, when the undulating road component is the maximum value, the road surface index corresponding to the undulating road becomes 1. In this way, the road surface index becomes a value standardized between 0 and 1. That is, the road surface index is obtained by indexing the vertical, pitch, and roll motions (0.5 to 2 Hz) of the vehicle body 2 based on the road surface input to 0 to 1.

[0200] The road surface index calculation unit 32 is not limited to obtaining the sprung speed from the state estimation unit 12, but may also obtain detection values ​​from a vertical acceleration sensor to calculate the road surface index. The road surface index calculation unit 32 may also obtain road surface information in the vehicle's traveling direction from a camera or the like to calculate the road surface index.

[0201] The weight estimating unit 33 acquires the absolute vertical displacement of the vehicle body 2, etc., based on the CAN signal, for example. The weight estimating unit 33 estimates the weight of the vehicle body 2 based on the absolute vertical displacement of the vehicle body 2, etc., and outputs the estimated weight to the GSP calculating unit 34. In addition, the weight estimating unit 33 is not limited to estimating the weight of the vehicle body 2 based on the absolute vertical displacement of the vehicle body 2, etc., and may estimate the weight of the vehicle body 2 based on, for example, a signal from a stroke sensor that detects the stroke of the variable damper 7. The weight estimating unit 33 may also acquire a detection value from a weight sensor that detects the weight of the vehicle body to obtain the weight of the vehicle body 2.

[0202] The GSP calculation unit 34 (gain scheduling parameter calculation unit) constitutes a weight coefficient calculation unit that calculates a weight coefficient that makes the actual target damping force based on the calculated value of the state estimation unit 12 (vehicle behavior calculation unit) close to a value close to the pre-calculated target damping force. The GSP calculation unit 34 is input with, for example, the vehicle speed obtained from CAN9, the road surface index from the road surface index calculation unit 32, and the estimated weight from the weight estimation unit 33. In addition, the GSP calculation unit 34 is input with the car mode as the damping force mode. In this case, the car mode includes, for example, three modes: normal mode (Normal), sports mode (Sport), and comfort mode (Comfort). The car mode is selected, for example, by a mode selection switch (not shown) provided on the vehicle. For the GSP calculation unit 34, the vehicle speed, road surface index, weight estimation unit, car mode, calculation of the vertical GSP, the roll GSP r , Pitch GSP p In addition, the car mode is not limited to three modes, and may have two modes or may have four or more modes.

[0203] That is, when the BLQ controller 20 obtains the actual target damping force based on the calculated value of the state estimation unit 12 (vehicle behavior calculation unit), that is, the vehicle state (for example, the relative speed between the sprung and unsprung vehicles, the absolute vertical speed of the vehicle body, the relative speed between the unsprung vehicles and the road surface, the absolute vertical speed of the unsprung vehicles, the roll rate, the roll angle, the pitch rate, the pitch angle, etc.), the GSP calculation unit 34 calculates the weight coefficient (heave GSP, roll GSP) that makes the actual target damping force close to the value close to the pre-derived target damping force. r , Pitch GSP p The GSP calculation unit 34 calculates the heave GSP and the roll GSP r , Pitch GSP p Output to BLQ controller 20.

[0204] like Fig.17 As shown, the GSP calculation unit 34 includes, for example, a recording unit for recording vehicle speed, road surface index, estimated weight, vehicle model, heave GSP, and roll GSP. r , Pitch GSP p At this time, the heave GSP and roll GSP r , Pitch GSP p It is determined by tuning in actual vehicle tests. Specifically, the heave GSP is fine-tuned with reference to vibration data, etc. after the general characteristics are determined by sensory evaluation based on actual vehicle tests. In addition, the GSP calculation unit 34 has a lookup table that records the relationship between the vehicle speed, road surface index, estimated weight, vehicle mode and the roll GSP, and a lookup table that records the relationship between the vehicle speed, road surface index, estimated weight, vehicle mode and the pitch GSP. Roll GSP r , Pitch GSPp It is also determined by tuning in actual vehicle testing, similarly to the heave GSP.

[0205] The GSP calculation unit 34 is, for example, Fig.17 As shown, a small value of the heave GSP is calculated at a low speed, and a large value of the heave GSP is calculated at a high speed. The GSP calculation unit 34 increases the value of the heave GSP when a rough road is determined based on the road surface index. The GSP calculation unit 34 increases the value of the heave GSP when the estimated weight is large compared to when the estimated weight is small. When the vehicle mode is the sport mode, the GSP calculation unit 34 increases the value of the heave GSP compared to when the vehicle mode is the normal mode. When the vehicle mode is the comfort mode, the GSP calculation unit 34 decreases the value of the heave GSP compared to when the vehicle mode is the normal mode. The GSP calculation unit 34 calculates the roll GSP corresponding to the vehicle speed, road surface index, estimated weight, and vehicle mode in the same way as the heave GSP. r , Pitch GSP p .

[0206] exist Fig.17 In the example, the GSP calculation unit 34 includes three lookup tables corresponding to the road surface index, the estimated weight, and the vehicle model. The GSP calculation unit 34 calculates the heave GSP and the roll GSP in consideration of these three lookup tables. r , Pitch GSP p The present invention is not limited to this. The GSP calculation unit 34 may also be based on Fig.17 The three lookup tables in the above are combined into a single lookup table to calculate the heave GSP and roll GSP. r , Pitch GSP p .

[0207] In this way, in the second embodiment, it is possible to obtain substantially the same effects as those in the first embodiment. In the second embodiment, the weight coefficient calculation unit (GSP calculation unit 34) changes the coefficient according to the state of the road surface. Therefore, the actual target damping force can be changed according to the state of the road surface to improve ride comfort and vehicle stability. The weight coefficient calculation unit (GSP calculation unit 34) changes the coefficient according to the weight of the vehicle body 2. Therefore, the actual target damping force can be changed according to the weight of the vehicle body 2 to improve ride comfort and vehicle stability. The weight coefficient calculation unit (GSP calculation unit 34) changes the coefficient according to the selected damping force mode (car mode). Therefore, the actual target damping force can be changed according to the selected car mode to improve ride comfort and vehicle stability.

[0208] In the second embodiment, the GSP calculation unit 34 calculates the weight coefficients (heave GSP, roll GSP) based on the road surface index, the estimated weight, and the vehicle model. r , Pitch GSP p), but the present invention is not limited thereto. The GSP calculation unit 34 may also calculate the weight coefficient (heave GSP, roll GSP) based on any one or two of the road surface index, estimated weight, and vehicle model. r , Pitch GSP p ).

[0209] In the second embodiment, the road surface index is exemplified as a rough road index, but the present invention is not limited thereto. The road surface index may be an index corresponding to a road surface condition other than a rough road, such as a bad road.

[0210] then, Figure 1 , Figure 2 , Figures 18 to 22 The third embodiment is shown. The third embodiment is characterized in that the weight coefficient calculation unit changes the coefficient according to the weight balance of the front and rear of the vehicle body and the weight of the vehicle body obtained in advance. In addition, in the third embodiment, the same reference numerals are attached to the same components as those in the first and second embodiments, and their descriptions are omitted.

[0211] The controller 41 of the third embodiment constitutes a control device for the variable damper 7, and controls the damping characteristics of the variable damper 7 (see Figure 1 , Figure 2 ). The controller 41 is configured in substantially the same manner as the controller 11 of the first embodiment. The controller 41 is, for example, a microcomputer and is connected to the CAN 9. The controller 41 obtains parameters related to the driving of the vehicle through the CAN 9. The output side of the controller 41 is connected to the damping force variable actuator 8 of the variable damper 7.

[0212] The controller 41 also includes a storage unit 41A composed of a ROM, a RAM, a nonvolatile memory, etc. The storage unit 41A of the controller 41 stores various programs, information (vehicle information), data, etc. for controlling the variable damper 7 .

[0213] like Fig.18 As shown, the controller 41 includes the state estimating unit 12, the GSP calculating unit 34, and the BLQ controller 42. In addition, the controller 31 includes the road surface index calculating unit 32 and the weight estimating unit 33.

[0214] The BLQ controller 42 calculates the command current (control signal) which becomes the command value based on the bilinear optimal control theory. The BLQ controller 42 is configured in the same manner as the BLQ controller 20 of the first embodiment. Fig.19 As shown, the BLQ controller 42 includes a sprung vertical vibration damping BLQ43 , a roll vibration damping BLQ44 , a pitch vibration damping BLQ45 , a target damping force calculation unit 24 , a damping coefficient upper limit calculation unit 25 , a correction damping coefficient calculation unit 26 , and a command value calculation unit 29 .

[0215] The sprung up and down vibration damping BLQ43 is configured in the same manner as the sprung up and down vibration damping BLQ21 of the first embodiment. The sprung up and down vibration damping BLQ43 is input with the vehicle state output from the state estimation unit 12, the heave GSP output from the GSP calculation unit 34, and the estimated weight output from the weight estimation unit 33. The sprung up and down vibration damping BLQ43 calculates the heave target damping force of the variable damper 7 for reducing the up and down vibration based on the sprung-unsprung relative speed output from the state estimation unit 12, the vehicle body absolute up and down speed, the unsprung-road relative speed, the unsprung absolute up and down speed, the heave GSP output from the GSP calculation unit 34, and the estimated weight output from the weight estimation unit 33, divided into the front wheel and the rear wheel.

[0216] like Fig. 20 As shown, the sprung vertical damping BLQ43 includes a correction gain calculation unit 43A, a Bp calculation unit 43B, a multiplier 43C, a Bp calculation unit 43D, a multiplier 43E, a multiplier 43F, and a heave target damping force calculation unit 43G. The correction gain calculation unit 43A calculates the correction gain for the front wheel and the correction gain for the rear wheel based on the estimated weight. The Bp calculation unit 43B finds the maximum value of Bp corresponding to the relative speed based on the Bp and heave GSP obtained in advance. The multiplier 43C multiplies the correction gain output from the correction gain calculation unit 43A, the maximum value of Bp output from the Bp calculation unit 43B, and the relative speed. The Bp calculation unit 43D finds the maximum value of Bp corresponding to the sprung speed based on the Bp and heave GSP obtained in advance. The multiplier 43E multiplies the correction gain output from the correction gain calculation unit 43A, the maximum value of Bp output from the Bp calculation unit 43D, and the sprung speed. The multiplier 43F multiplies the calculated value of the multiplier 43C by the calculated value of the multiplier 43E. The heave target damping force calculation unit 43G multiplies the calculated value of the multiplier 43F by the inverse matrix of R (R -1 ) are multiplied to calculate the heave target damping force for the front wheels and the heave target damping force for the rear wheels. In addition, the case where the sprung up-and-down vibration damping BLQ43 calculates the heave target damping force based on the Bp corresponding to the relative speed and the Bp corresponding to the sprung speed is exemplified, but the present invention is not limited thereto. The sprung up-and-down vibration damping BLQ43 may calculate the heave target damping force based on the Bp corresponding to other vehicle states in addition to the relative speed and the Bp corresponding to the sprung speed.

[0217] The roll damping BLQ44 receives the vehicle state output from the state estimation unit 12 and the roll GSP output from the GSP calculation unit 34 as input. r, and the estimated weight output from the weight estimating unit 33. The roll damping BLQ22 calculates the roll target damping force of the variable damper 7 for reducing the roll vibration, divided into the front wheel and the rear wheel, based on the roll rate and roll angle output from the state estimating unit 12, the roll GSP output from the GSP calculating unit 34, and the estimated weight output from the weight estimating unit 33.

[0218] like Fig.21 As shown, the roll damping BLQ44 includes a correction gain calculation unit 44A, a Bp calculation unit 44B, multipliers 44C, 44D, and a roll target damping force calculation unit 44E. The correction gain calculation unit 44A calculates the correction gain for the front wheels and the correction gain for the rear wheels based on the estimated weight. The Bp calculation unit 44B calculates the correction gain for the front wheels based on the Bp calculated in advance. roll p roll and roll GSP r , find the B corresponding to the roll rate roll p roll The multiplier 44C multiplies the correction gain output from the correction gain calculation unit 44A by the Bp output from the Bp calculation unit 44B. roll p roll The multiplier 44D multiplies the value calculated by the multiplier 44C by the roll rate. The roll target damping force calculation unit 44E multiplies the value calculated by the multiplier 44D by the R value calculated in advance. roll The inverse matrix (R roll -1 ) are multiplied together to calculate the roll target damping force for the front wheels and the roll target damping force for the rear wheels.

[0219] The pitch vibration reduction BLQ45 receives the vehicle state output from the state estimation unit 12 and the pitch GSP output from the GSP calculation unit 34 as input. p , and the estimated weight output from the weight estimating unit 33. The pitch vibration reduction BLQ 45 is based on the pitch rate and pitch angle output from the state estimating unit 12 and the pitch GSP output from the GSP calculating unit 34. p , which is divided into the front wheel and the rear wheel and is used to calculate the pitch target damping force of the variable damper 7 for reducing the pitch vibration.

[0220] like Fig. 22 As shown, the pitch vibration reduction BLQ45 includes a correction gain calculation unit 45A, a Bp calculation unit 45B, multipliers 45C, 45D, and a pitch target damping force calculation unit 45E. The correction gain calculation unit 45A calculates the correction gain for the front wheels and the correction gain for the rear wheels based on the estimated weight. The Bp calculation unit 45B calculates the correction gain for the front wheels based on the Bp calculated in advance. pitch p pitch and pitch GSP p , find the B corresponding to the pitch rate pitch p pitchThe multiplier 45C multiplies the correction gain output from the correction gain calculation unit 45A by the Bp output from the Bp calculation unit 45B. pitch p pitch The multiplier 45D multiplies the value calculated by the multiplier 45C by the pitch rate. The pitch target damping force calculation unit 45E multiplies the value calculated by the multiplier 45D by the R value calculated in advance. pitch The inverse matrix (R pitch -1 ) are multiplied to calculate the pitch target damping force for the front wheels and the pitch target damping force for the rear wheels.

[0221] In this case, the GSP calculation unit 34 and the correction gain calculation units 43A, 44A, and 45A constitute a weight coefficient calculation unit.

[0222] Thus, in the third embodiment, the same effects as those in the first and second embodiments can be obtained. In the third embodiment, the weight coefficient calculation unit (GSP calculation unit 34, correction gain calculation unit 43A, 44A, 45A) changes the coefficient according to the weight balance of the front and rear of the vehicle body 2 and the weight of the vehicle body 2 obtained in advance. Specifically, the heave BLQ (sprung vertical damping BLQ21), the roll BLQ (roll damping BLQ22), and the pitch BLQ (pitch damping BLQ23) calculate the heave target damping force, the roll target damping force, and the pitch target damping force in consideration of the weight balance of the front and rear of the vehicle body. Therefore, the ratio of the target damping force on the front wheel side to the target damping force on the rear wheel side can be adjusted at a ratio corresponding to the weight of the vehicle. As a result, even when the ride comfort and vehicle stability of the vehicle change according to the number of passengers, the load weight, etc. of the vehicle, the ride comfort can be improved.

[0223] In the third embodiment, the controller 41 includes the GSP calculation unit 34 of the second embodiment, but may also include the GSP calculation unit 13 of the first embodiment. In addition, in the third embodiment, the weight coefficient calculation unit is composed of the GSP calculation unit 34 and the correction gain calculation units 43A, 44A, and 45A. The present invention is not limited to this, and the GSP calculation unit 34 and the correction gain calculation units 43A, 44A, and 45A may be combined to form a lookup table, and the weight coefficient calculation unit is composed of the lookup table.

[0224] in addition, Figure 4 , Fig.17 An example of a lookup table constituting the GSP calculation unit 13, 34 is shown. Figure 6 2 shows an example of the damping coefficient upper limit calculation unit 25. Figure 7 This is an example of the command value calculation unit 29, and the present invention is not limited thereto. The GSP calculation unit, the damping coefficient upper limit calculation unit, and the command value calculation unit are appropriately set in consideration of vehicle parameters and the like.

[0225] In the above-mentioned embodiments, the controller 11, 31, 41 is described as an example in which the controller 11, 31, 41 obtains the parameters related to the driving of the vehicle through the CAN 9, but the present invention is not limited thereto. The controller 11, 31, 41 may be connected to an acceleration sensor for detecting the vertical acceleration of the sprung and unsprung parts, a wheel speed sensor for detecting the wheel speed, etc., and obtain the detection values ​​of these sensors as the parameters related to the driving of the vehicle. In addition, the controller 11, 31, 41 may also obtain the parameters related to the driving of the vehicle from other controllers, etc.

[0226] In each of the above embodiments, the controller 11, 31, 41 is provided with a state estimation unit 12 including a vertical motion calculation unit, a roll motion calculation unit, and a pitch motion calculation unit. At this time, the state estimation unit 12 obtains the state related to the vertical motion of the vehicle based on the CAN signal, obtains the state related to the roll motion of the vehicle based on the CAN signal, and obtains the state related to the pitch motion of the vehicle based on the CAN signal. The present invention is not limited to this. For example, the controller 11, 31, 41 can also be connected to an acceleration sensor, a roll sensor, a pitch sensor, etc. in the vertical direction, and calculates the state related to the vertical motion of the vehicle, the state related to the roll motion of the vehicle, and the state related to the pitch motion of the vehicle based on the detection values ​​of these sensors. In this case, the part of the controller 11, 31, 41 that calculates each state constitutes the vertical motion calculation unit, the roll motion calculation unit, and the pitch motion calculation unit.

[0227] In the above-mentioned embodiments, the variable damper 7 composed of a semi-active damper is used as an example of a damping force adjustable damper. The present invention is not limited to this, and an active damper (either an electric actuator or a hydraulic actuator) may be used as the damping force adjustable damper. In the above-mentioned embodiments, the variable damper 7 composed of a hydraulic damper is used as an example of a damping force adjustable damper that generates a force adjustable between the vehicle body 2 side and the wheel 3 side. The present invention is not limited to this, and for example, in addition to the hydraulic damper, the damping force adjustable damper may be composed of an air suspension, an electromagnetic suspension, or the like.

[0228] In the above-mentioned embodiments, the vehicle behavior device for a four-wheeled vehicle is used as an example for description, but the present invention is not limited thereto, and can also be applied to a two-wheeled or three-wheeled vehicle, or a work vehicle, a truck or a bus as a transport vehicle, etc.

[0229] The specific numerical values ​​described in the above-mentioned embodiments are examples, and the present invention is not limited to the values ​​described in the examples. In addition, the above-mentioned embodiments are examples, and it is of course possible to partially replace or combine the configurations shown in different embodiments.

[0230] In addition, the present invention is not limited to the above-mentioned embodiments, and includes various modified examples. For example, the above-mentioned embodiments are described in detail in order to explain the present invention in an easy-to-understand manner, and are not limited to having all the described structures. In addition, a part of the structure of a certain embodiment can be replaced with the structure of other embodiments, and in addition, the structure of other embodiments can be added to the structure of a certain embodiment. In addition, for a part of the structure of each embodiment, other structures can be added, deleted, or replaced.

[0231] This application claims the benefit of priority based on Japanese Patent Application No. 2022-207940 filed on December 26, 2022. The entire disclosure of Japanese Patent Application No. 2022-207940 filed on December 26, 2022, including the specification, claims, drawings, and abstract, is incorporated herein by reference in its entirety.

[0232] Description of Reference Numerals

[0233] 1: Vehicle behavior control device; 2: Vehicle body; 3: Wheel; 5: Suspension device; 7: Damping force adjustable buffer (variable damper); 8: Damping force variable actuator; 9: CAN; 11, 31, 41: Controller (control device); 12: State estimation unit (Vehicle behavior calculation unit, up and down motion calculation unit, roll motion calculation unit, pitch motion calculation unit, attitude change detection unit); 13, 34: GSP calculation unit (weight coefficient calculation unit); 20, 42: BLQ controller; 21, 43: Sprung up and down vibration reduction BLQ (heave BLQ); 22, 44: roll vibration reduction BLQ (roll BLQ); 23, 45: pitch vibration reduction BLQ (pitch BLQ); 24: target damping force calculation unit (actual target damping force calculation unit); 25: damping coefficient upper limit calculation unit; 26: correction damping coefficient calculation unit; 27: target damping coefficient calculation unit (target damping coefficient calculation unit); 28: minimum value selection unit (correction unit); 29: instruction value calculation unit (control signal output unit); 32: road surface index calculation unit; 33: weight estimation unit.

Claims

1. A control device for a damping force adjustable shock absorber, arranged on a vehicle, capable of adjusting the damping force generated, characterized in that: The control device of the damping force adjustable buffer comprises: a weight coefficient calculation unit that calculates a weight coefficient for making the actual target damping force approach a value close to the target damping force obtained in advance when calculating the actual target damping force based on the calculated value of the vehicle behavior calculation unit; a vertical motion calculation unit for calculating a vertical motion state of the vehicle; a pitch motion calculation unit for obtaining a motion state of the vehicle in a pitch direction; an actual target damping force calculation unit that calculates the actual target damping force based on the weight coefficient of the weight coefficient calculation unit and calculation results of the up-and-down motion calculation unit and the pitch motion calculation unit; a target damping coefficient calculation unit that calculates a target damping coefficient based on the calculated value of the actual target damping force calculation unit; a correction unit that calculates a correction damping coefficient that reduces an upper limit of the target damping coefficient in a region where a relative speed between the sprung and unsprung components of the vehicle is lower than a predetermined value; as well as a control signal output unit that outputs a control signal corresponding to the corrected damping coefficient to the damping force adjustable shock absorber, The correction unit sets the correction damping coefficient so that the damping force increases as the relative speed increases, and the slope of the damping force with respect to the relative speed decreases when the relative speed is lower than the predetermined value, and increases when the relative speed is higher than the predetermined value. The correction unit has a maximum damping coefficient according to the relative speed, and corrects the target damping coefficient to the maximum damping coefficient when the target damping coefficient exceeds the maximum damping coefficient.

2. The control device according to claim 1, characterized in that: The device further comprises a posture change detection unit for detecting a posture change of the vehicle body. The correction unit reduces the correction amount when determining that a posture change has occurred based on the detection result of the posture change detection unit.

3. The control device according to claim 1, characterized in that: The vehicle further includes a roll motion calculation unit for obtaining a motion state in a roll direction of the vehicle.

4. The control device according to claim 1, characterized in that: The weight coefficient calculation unit changes the weight coefficient according to a state of a road surface.

5. The control device according to claim 1, characterized in that: The weight coefficient calculation unit changes the weight coefficient according to the weight of the vehicle body.

6. The control device according to claim 1, characterized in that: The weight coefficient calculation unit changes the weight coefficient according to the selected damping force mode.

7. The control device according to claim 1, characterized in that: The weight coefficient calculation unit changes the weight coefficient based on a previously determined front-rear weight balance of a vehicle body and the weight of the vehicle body.

8. The control device according to claim 1, characterized in that: The weight coefficient calculation unit calculates, as the weight coefficients, a heave GSP associated with the vertical motion of the vehicle and a pitch GSP associated with the pitch motion of the vehicle. The actual target damping force calculation unit includes: a heave BLQ that calculates a target damping force in the vertical direction of the vehicle based on the heave GSP and a calculation result of the vertical motion calculation unit; and a pitch BLQ that calculates a target damping force in the pitch direction of the vehicle based on the pitch GSP and a calculation result of the pitch motion calculation unit, The actual target damping force calculation unit calculates the actual target damping force based on the target damping force calculated by the heave BLQ and the target damping force calculated by the pitch BLQ.

9. The control device according to claim 3, characterized in that: The weight coefficient calculation unit calculates, as the weight coefficients, a heave GSP related to the movement of the vehicle in the up-down direction, a roll GSP related to the movement of the vehicle in the roll direction, and a pitch GSP related to the movement of the vehicle in the pitch direction. The actual target damping force calculation unit includes: a heave BLQ that calculates a target damping force in the vertical direction of the vehicle based on the heave GSP and a calculation result of the vertical motion calculation unit; A roll BLQ that calculates a target damping force in the roll direction of the vehicle based on the roll GSP and a calculation result of the roll motion calculation unit; and a pitch BLQ that calculates a target damping force in the pitch direction of the vehicle based on the pitch GSP and a calculation result of the pitch motion calculation unit, The actual target damping force calculation unit calculates the actual target damping force based on the target damping force calculated by the heave BLQ, the target damping force calculated by the roll BLQ, and the target damping force calculated by the pitch BLQ.

10. The control device according to claim 9, characterized in that: The heave BLQ, the roll BLQ, and the pitch BLQ are used to calculate a target damping force in consideration of the front and rear weight balance of a vehicle body.

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