JP2016022830A - Control device of attenuation force variable damper - Google Patents

Abstract

PROBLEM TO BE SOLVED: To further accurately calculate a state amount of a vehicle which is used for the attenuation force control of a damper when the vehicle turns.SOLUTION: Steering influence amount correction means (53, 54 and 35) which correct wheel speed variation amounts (Vw for use in the calculation of ΔVw) so that change amounts (Vb, Vb) of the wheel speed variation amounts generated by an influence of steering are eliminated comprise: a rear wheel turning radius calculation means (80A) which calculates turning radii R, Rof a right rear wheel and a left rear wheel; front wheel turning radius calculation means (80B) which calculates turning radii R, Rof a right front wheel and a left front wheel on the basis of the turning radii of the calculated right rear wheel and the left rear wheel, and a wheel base; and change amount calculation means (80C, 54) which calculate change amounts (Vb, Vb) of the wheel speed change amounts generated by the influence of steering on the basis of front wheel turn ratios (RR, RR) being ratios of the turning radii of the right front wheel and the left front wheel with respect to a vehicle body turning radius (R).SELECTED DRAWING: Figure 10

Description

  The present invention relates to a control device for a variable damping force damper that calculates a state quantity of a vehicle based on a detected fluctuation amount of wheel speed and controls a damping force of the damper.

  2. Description of the Related Art In recent years, various types of damping force variable type dampers that can variably control damping force stepwise or steplessly have been developed as dampers used in automobile suspensions. As a mechanism to change the damping force, in addition to a mechanical type that changes the area of the orifice provided in the piston by a rotary valve, a magnetic viscous fluid (Magneto-Rheological Fluid: hereinafter referred to as MRF) is used as the hydraulic oil. An MRF type in which the viscosity of the MRF is controlled by an installed magnetic fluid valve is known. In a vehicle equipped with such a variable damping force damper (hereinafter simply referred to as a damper), the damping force of the damper is variably controlled in accordance with the running state of the vehicle, thereby improving steering stability and ride comfort. Is possible.

  Skyhook control based on skyhook theory is known as one of the techniques for improving riding comfort. In skyhook control in which ride comfort control (vibration control) is performed, the target damping force is set so as to suppress the vertical movement on the spring, so it is necessary to detect the sprung speed. Further, as a characteristic of the damper, even if the area of the orifice and the viscosity of the MRF are constant, the damping force changes according to the stroke speed. It is also necessary to detect the relative displacement speed with the bottom.

  Conventionally, in suspension control devices that perform skyhook control, it has been necessary to mount a vertical G sensor and a stroke sensor for each wheel in order to detect the vertical speed and stroke speed on the spring. However, since the stroke sensor is attached in the wheel house or in the vicinity thereof, it is difficult to secure an arrangement space. Therefore, in order to solve this problem, the relative displacement speed between the sprung and unsprung mass is calculated from the fluctuation amount of the wheel speed without installing a stroke sensor, and the damping force of the damper is calculated based on the calculated relative displacement speed. A suspension control device has been proposed (see Patent Document 1).

  On the other hand, in the suspension control described in Patent Document 1, the relative displacement speed cannot be calculated when there is no caster angle set for the suspension or when the suspension is small. In view of this, the present applicant has proposed a suspension control device capable of calculating a state quantity of a vehicle used for damping force control of a damper with high accuracy regardless of a caster angle (see Patent Document 2). In the present invention, the inner ring vehicle body speed ratio (ratio of the inner ring turning radius to the vehicle body turning radius) and the outer ring vehicle body speed ratio (ratio of the outer ring turning radius to the vehicle body turning radius) are calculated as the turning state quantity of the vehicle. By correcting the detection value of the wheel speed sensor based on the speed ratio and the outer wheel body speed ratio, the effect on the wheel speed due to the steering is removed, and the sprung speed of the vehicle body and the suspension Vehicle state quantities such as stroke speed are calculated.

JP-A-6-48139 International Publication No. 2014/002444

  However, in the suspension control device of Patent Document 2, the turning radius is calculated from the yaw rate and the vehicle speed of the vehicle body, and the inner wheel body speed ratio and the outer wheel body speed ratio are calculated by simply adding and subtracting 1/2 of the tread to the turning radius. doing. Therefore, if the turning radius is small and the geometrical influence of the vehicle body such as tread or wheelbase becomes relatively large, such as when turning at low speed, the amount of correction for the steering influence becomes excessive and insufficient. The estimation accuracy of the state quantity may be lowered, and further improvement in estimation accuracy is desired.

  The present invention has been devised to solve such problems included in the prior art, and can further increase the state quantity of the vehicle used for damping force control of the damper even when the vehicle is turning. An object of the present invention is to provide a control device for a damping force variable damper that can be calculated with high accuracy.

In order to solve such a problem, the present invention is based on a wheel speed sensor (9) that detects a wheel speed (Vw) of each wheel (3) and a wheel speed detection value detected by the wheel speed sensor. Wheel speed fluctuation amount calculating means (36) for calculating the wheel speed fluctuation amount (ΔVw), and at least one of the sprung speed (S ₂ ) of the vehicle body and the stroke speed (Ss) of the suspension based on the wheel speed fluctuation amount. A state quantity calculating means (33) for calculating a state quantity of the vehicle (V) including the damping force of the variable damping force damper based on at least one of the sprung speed and the stroke speed calculated by the state quantity calculating means. A control device (8) for a damping force variable damper (6) comprising control means (23, 25) for controlling the change amount (Vb _FL , Vb _FR ) of the wheel speed fluctuation amount due to the influence of turning. Remove Further, a steering influence correction means (53, 54, 35) for correcting the wheel speed fluctuation amount (Vw used for calculating ΔVw) is further provided, and the steering influence correction means includes a right rear wheel and a left rear wheel. Using the rear wheel turning radius calculating means (80A) for calculating the turning radius (R _RR , R _RL ) of the vehicle, and the calculated turning radius and wheel base (WB) of the right rear wheel and the left rear wheel. Front wheel turning radius calculation means (80B) for calculating the turning radius (R _FR , R _FL ) of the front wheel and the left front wheel, and the ratio of the turning radius of the right front wheel and the turning radius of the left front wheel to the vehicle turning radius (R) Based on a certain front-wheel turning radius ratio (RR _FL , RR _FR ), change amount calculation means (80C, 54) for calculating a change amount of the wheel speed fluctuation amount due to the influence of the steering is provided.

  According to this configuration, the wheel speed fluctuation amount used for calculating the state quantity of the vehicle is corrected so that the change due to the influence of the steering calculated based on the front-wheel turning radius ratio is removed. Even when the turning radius is small and the geometrical influence of the vehicle body is relatively large, the state quantity of the vehicle used for damper damping force control can be calculated with high accuracy.

In the above invention, the front wheel turning radius calculating means (80B) uses the value (Vb · G ₃ ) obtained by correcting the wheel base depending on the vehicle speed (Vb), and uses the right front wheel and the left front wheel. The turning radius (R _FR , R _FL ) may be calculated.

  According to this configuration, the influence of the wheelbase on the turning radius of the front wheel calculated using the turning radius of the rear wheel changes due to the movement of the turning center depending on the vehicle speed. Thus, the turning radius of the front wheel can be calculated with higher accuracy, and the state quantity of the vehicle can be calculated with higher accuracy.

In the above invention, the rear wheel turning radius calculating means (80A) corrects the vehicle body turning radius (R), the tread (T), and the wheel base depending on the vehicle speed (Vb) ( The turning radius (R _RR , R _RL ) of the right rear wheel and the left rear wheel may be calculated using Vb · G ₃ ).

  According to this configuration, when calculating the turning radius of the rear wheel, the turning radius of the rear wheel calculated using the wheel speed fluctuation amount is caused by the movement of the turning center depending on the vehicle speed. Corresponding to the influence of the wheel base, the turning radius of the rear wheel can be calculated with higher accuracy, and the state quantity of the vehicle can be calculated with higher accuracy.

Further, in the above invention, the rear wheel turning radius calculating means (80A), the right rear wheel and after the left the tread with a vehicle speed correction value in dependence on _{(Vb) (G 5 · T} ) A configuration may be _{employed in which} the turning radius (R _RR , R _RL ) of the wheel is calculated.

  According to this configuration, when calculating the turning radius of the rear wheel, the influence of the tread on the turning radius of the rear wheel calculated using the tread is caused by the movement of the turning center depending on the vehicle speed. In response to the change, the turning radius of the rear wheel can be calculated with higher accuracy, and the state quantity of the vehicle can be calculated with higher accuracy.

In the above invention, the vehicle includes a rear wheel steering device (14) for changing a toe angle of the rear wheel,
The front wheel turning radius calculating means (80A), the wheelbase by using the steering angle value corrected depending on _{(δra) (G 4 · WB} ) of the rear wheel, the turning of the right front wheel and the left front wheel The radius may be calculated.

  In a vehicle equipped with a rear wheel steering device, even if the steering angle of the rear wheel is changed during a turn, the turning influence is caused by the movement of the turning center depending on the steering angle of the rear wheel. However, according to this configuration, the influence of the wheel base on the turning radius of the front wheel calculated using the turning radius of the rear wheel changes in response to the change in the wheel base. The turning radius can be calculated with higher accuracy, and the state quantity of the vehicle can be calculated with higher accuracy.

In the above invention, the rear wheel turning radius calculating means (80A) depends on the vehicle body turning radius (R), the tread (T), and the wheel base depending on the steering angle (δra) of the rear wheel. The turning radius of the right front wheel and the left front wheel may be calculated using the corrected value (G ₄ · WB).

  According to this configuration, when calculating the turning radius of the rear wheel, the rear wheel calculated using the wheel speed fluctuation amount due to the movement of the turning center depending on the steering angle of the rear wheel. Corresponding to the change in the influence of the wheel base on the turning radius, the turning radius of the rear wheel can be calculated with higher accuracy, and the state quantity of the vehicle can be calculated with higher accuracy.

  Thus, according to the present invention, it is possible to provide a control device for a damping force variable damper that can calculate the state quantity of the vehicle used for damping force control of the damper with higher accuracy even when the vehicle is turning. it can.

1 is a schematic configuration diagram of a vehicle to which a damping force variable damper control device according to a first embodiment is applied. Model diagram of suspension shown in Fig. 1 The block diagram which shows schematic structure of the control apparatus of the damping force variable damper shown in FIG. Block diagram of the state quantity estimation unit shown in FIG. Time chart showing the relationship between wheel speed and contact load in the unsprung load single wheel model shown in FIG. FIG. 4 is a graph showing the correlation between the wheel speed fluctuation amount and the ground load fluctuation in the unsprung load single wheel model shown in FIG. Block diagram of the unsprung load single wheel model calculation unit shown in FIG. Block diagram of the vehicle speed estimation unit shown in FIG. Main part control block diagram of the vehicle speed estimation unit shown in FIG. Block diagram of the steering correction amount calculation unit shown in FIG. (A) Explanatory drawing of turning radius of each wheel at low speed turning, (B) Explanatory drawing of turning radius of each wheel at middle / high speed turning (A) Explanatory diagram of turning radius of each wheel when rear wheel is steered in opposite phase to front wheel, (B) Explanatory diagram of turning radius of each wheel when rear wheel is steered in phase with front wheel (A) A time chart comparing the estimated value of the sprung speed with the single wheel model shown in FIG. 4 and the sensor value, and (B) a time chart comparing the estimated value of the stroke speed with the sensor value of the single wheel model shown in FIG. Block diagram of skyhook control calculation unit shown in FIG. Target current map used by the target current setting unit shown in FIG. Block diagram of the unsprung vibration suppression control calculation section shown in FIG. Frequency response diagram showing wheel speed versus unsprung acceleration Time chart showing unsprung acceleration and target current by peak hold / ramp down circuit shown in FIG. (A) Time chart of wheel speed fluctuation amount before and after low-pass filter processing during flat road travel, (B) Time chart of wheel speed fluctuation amount before and after low-pass filter processing during rough paved road travel FIG. 3 is a flowchart showing the procedure of damping force control by the damping force variable damper control device shown in FIG.

Hereinafter, an embodiment in which a control device for a damping force variable damper according to the present invention (hereinafter simply referred to as a control device 20) is applied to a four-wheeled vehicle will be described in detail with reference to the drawings. In the figure, the four wheels 3 and the elements arranged with respect to them, that is, the damper 6 and the wheel speed Vw, are attached with subscripts indicating front, rear, left and right respectively, for example, and the wheels, for example, 3 _FL (front left), wheel 3 _FR (front right), wheel 3 _RL (back left), wheel 3 _RR (back right) are described. In addition, when a part of the elements with subscripts attached to the reference is collectively indicated, for example, the front wheel 3 _F and the rear wheel 3 _R are described.

≪Schematic configuration of car V≫
First, a schematic configuration of the automobile V according to the embodiment will be described with reference to FIG. A vehicle body 1 of an automobile (vehicle) V has wheels 3 with tires 2 mounted on the front, rear, left and right thereof. These wheels 3 are each provided with a suspension arm 4, a spring 5, a variable damping force damper (hereinafter simply referred to as a damper). 6) and the like. The front wheel _3F is a steered wheel that is steered by steering, and the rear wheel _3R is a drive wheel that exhibits a driving force in accordance with an accelerator pedal operation. The vehicle V includes an ECU (Electronic Control Unit) 8 used for various controls, a wheel speed sensor 9 that detects a wheel speed Vw of each wheel 3 installed for each wheel 3, and a lateral acceleration of the vehicle body 1. A lateral G sensor 10 that detects Gy, a yaw rate sensor 11 that detects the yaw rate γ of the vehicle body 1, a steering angle sensor 12 that detects the steering angle δf, and the like are installed at appropriate positions of the vehicle body 1.

Further, the vehicle V is provided with a rear wheel steering device 14 including a pair of actuators 13 _R and 13 _L that individually change the toe angles of the left and right rear wheels 3 _R. Rear wheel steering device 14 is driven and controlled by ECU8 so that the target rear-wheel steering angle δr which is set according to the motion state of the vehicle V for each rear wheel 3 _R. When both actuators 13 are displaced symmetrically at the same time, the toe-in / to-out of both rear wheels 3 _RR and 3 _RL are changed, and when one actuator 13 is extended and the other actuator 13 is contracted, both rear wheels 3 _RR and _3RL are steered left and right. ECU8, for example, to increase the turning property and steering stability of the automobile V, and the rear wheel 3 _R to toe-out during acceleration, changing the rear wheel 3 _R toe-in during deceleration, cornering at a speed higher than a predetermined vehicle speed the rear wheel 3 _R to the front wheel 3 _F in phase at times, during cornering at a low speed than a predetermined vehicle speed causes toe change the rear wheel 3 _R to the front wheel 3 _F and anti-phase (turning). Stroke sensors 15 _R and 15 _L for detecting the actual rear wheel steering angle δra are attached to both actuators 13, and the ECU 8 detects the target rear wheel steering angle δr set by the detected actual rear wheel steering angle δra. Feedback control is performed so that they match.

  Although illustration is omitted, the vehicle V includes an ABS (Antilock Brake System) that prevents wheel lock during braking, a TCS (traction control system) that prevents wheel slipping during acceleration, or ABS and TCS. In addition, a brake device capable of VSA (Vehicle Stability Assist) control, which is known as a vehicle behavior stabilization control system having an automatic brake function for a yaw moment control during turning, a brake assist function, and the like, is mounted. These ABS, TCS, and VSA determine the slip state when the detected value of the wheel speed sensor 9 deviates by a predetermined value or more from the wheel speed based on the estimated vehicle body speed Vb, and optimal brake control according to the traveling state Alternatively, the vehicle behavior is stabilized by performing traction control control.

  In addition, a brake pressure sensor that detects the brake fluid pressure Pb of the brake device, a torque sensor that detects the engine torque Te, a gear position sensor that detects the gear position Pg of the transmission, and the like are set in place in the automobile V. Yes.

  The ECU 8 includes a microcomputer, a ROM, a RAM, peripheral circuits, input / output interfaces, various drivers, and the like. The damper of each wheel 3 is connected via a communication line (CAN 16 (Controller Area Network in this embodiment)). 6 and the sensors 9 to 12 and the like. The control device 20 is configured by the ECU 8 and these sensors 9 to 12.

  Although the detailed illustration of the damper 6 of this embodiment is omitted, it is a monotube type (de carvone type) so that the piston rod can slide in the axial direction with respect to a cylindrical cylinder filled with MRF. The piston inserted and attached to the tip of the piston rod divides the inside of the cylinder into an upper oil chamber and a lower oil chamber, and is located inside the communication passage that connects the upper oil chamber and the lower oil chamber and inside this communication passage The MLV coil is of a known configuration provided on the piston.

In the damper 6, the lower end of the cylinder is connected to the upper surface of the suspension arm 4 that is a wheel side member, and the upper end of the piston rod is connected to a damper base (upper part of the wheel house) that is a vehicle body side member. 2 schematically, each damper 6 has a mass composed of an unsprung mass having a mass M ₁ (a movable part below the suspension spring including the wheel 3, knuckle, and suspension arm 4) and the vehicle body 1. The spring 5 having M ₂ is connected together with the spring 5.

  When a current is supplied from the ECU 8 to the MLV coil, a magnetic field is applied to the MRF flowing through the communication path, and the ferromagnetic fine particles form a chain cluster. As a result, the apparent viscosity (hereinafter simply referred to as viscosity) of the MRF passing through the communication path increases, and the damping force of the damper 6 increases.

≪ECU8≫
Next, a schematic configuration of the ECU 8 that controls the damper 6 among the components of the control device 20 will be described with reference to FIG. The ECU 8 performs not only the control of the damper 6 but also the control of ABS, TCS, and VSA. However, the description of the vehicle behavior control unit that performs these controls is omitted here.

  The ECU 8 estimates the vehicle state quantity that estimates the state quantity of the automobile V from the input unit 21 connected to the sensors 9 to 12 and the vehicle behavior control unit described above via the CAN 16 and the detection signals of the sensors 9 to 12. From the various values calculated by the unit 22 and the vehicle state quantity estimation unit 22 and the detection signals of the sensors 9 to 12, various control targets of the dampers 6 are improved in order to improve the handling stability and riding comfort of the automobile V. Set by a control target current setting unit 23 for setting a current, a current fixing unit 24 for setting a current fixing signal Sfix to fix the drive current of the damper 6 according to a predetermined condition, and a control target current setting unit 23 The target current Atgt of each damper 6 is selected from the various control target currents generated, and the drive current to each damper 6 (MLV coil) is generated according to the current fixing signal Sfix to reduce the damper 6. And a damper control unit 25 for controlling the force is configured as a major component.

<Vehicle state quantity estimation unit 22>
The vehicle state quantity estimation unit 22 estimates the state quantity of the automobile V by utilizing the fact that the wheel speed fluctuation amount ΔVw has a certain relationship with the ground load fluctuation amount of the wheel 3 and is detected by the wheel speed sensor 9. Based on the value, a state quantity calculation unit 31 that estimates various state quantities of the vehicle V for each wheel using a vehicle model, and a vehicle body speed Vb (a left rear wheel vehicle body speed Vb) that is a wheel speed correction amount for the state quantity calculation unit 31 _RL , right rear wheel vehicle speed Vb _RR , left front wheel vehicle speed Vb _FL , right front wheel vehicle speed Vb _FR ). The state quantity calculation unit 31 includes a one-wheel model calculation unit 33, a four-wheel model calculation unit 34, and a slip determination unit 50 (see FIG. 4) for the front, rear, left and right wheels. The vehicle body speed estimation unit 32 includes an acceleration / deceleration force calculation unit 51, a steering correction amount calculation unit 53 that calculates a correction amount for removing a change due to the influence of the steering operation, and the like. Below, each part of the vehicle state quantity estimation part 22 is demonstrated in detail, referring FIGS. 4-11.

<State quantity calculation unit 31>
As shown in FIG. 4, in the state quantity calculation unit 31, the input wheel speed Vw (signal) is input to the subtractor 35 as an addition value. A left rear wheel body speed Vb _RL , a right rear wheel body speed Vb _RR , a left front wheel body speed Vb _FL or a right front wheel body speed Vb _{FR, which} will be described later, are input to the subtracter 35 as subtraction values. The wheel speed Vw is corrected by subtracting the left rear wheel body speed Vb _RL , the right rear wheel body speed Vb _RR , the left front wheel body speed Vb _FL or the right front wheel body speed Vb _FR from each wheel speed Vw.

The left rear wheel body speed Vb _RL , the right rear wheel body speed Vb _RR , the left front wheel body speed Vb _FL or the right front wheel body speed Vb _FR input to the subtractor 35 are, as will be described later, It is calculated in order to remove the wheel speed fluctuation component due to the difference in the trajectory length of each wheel due to the difference in the turning radius of the wheel and the turning posture of the vehicle body 1 (the relationship between the direction of the vehicle body 1 and the traveling direction). . That is, the subtractor 35 calculates the left rear wheel vehicle speed Vb _RL , the right rear wheel vehicle speed Vb _RR calculated by the vehicle body speed estimation unit 32 from the wheel speeds Vw before being input to the bandpass filter 36, the left front wheel vehicle body. By subtracting the speed Vb _FL or the right front wheel vehicle speed Vb _FR , the wheel speed Vw used for calculating the wheel speed fluctuation amount ΔVw is corrected so as to remove the change in the wheel speed fluctuation amount ΔVw due to the influence of steering. It functions as a steering influence correction means.

  The wheel speed Vw output from the subtracter 35 is input to the gain circuit 37 via the band pass filter 36. The bandpass filter 36 has a bandpass characteristic that allows a frequency component of 0.5 to 5 Hz to pass therethrough. In the present embodiment, the CAN 16 is used as the communication line, and the wheel speed Vw signal is input at an update period of about 10 to 20 msec. Therefore, the bandpass filter 36 blocks the high frequency component and the frequency component of the sprung resonance band. It has a low-pass characteristic that allows a band lower than about 5 Hz to pass through so that (a signal in a frequency range corresponding to the sprung vibration) can be reliably extracted. On the other hand, when the wheel speed Vw signal is input at a shorter update period, a bandpass filter 36 having a low-pass characteristic of a higher band such as 20 Hz is used so that the frequency component of the unsprung resonance band can be extracted. Also good.

  The band-pass filter 36 has a high-pass characteristic that allows a band higher than about 0.5 Hz to pass through in order to remove a DC component from the continuously input wheel speed Vw signal. As a result, the vehicle body speed Vb component (vehicle body speed component due to braking / driving force) caused by an operation by the driver or the like can be removed from the low-frequency signal of 5 Hz or less corresponding to the sprung vibration. That is, the bandpass filter 36 functions as a wheel speed fluctuation amount calculating means for calculating the wheel speed fluctuation amount ΔVw based on the wheel speed Vw. Since the DC component can be removed from the wheel speed Vw signal by the band pass filter 36, the subtractor 35 does not subtract the vehicle body speed Vb from the wheel speed Vw, but changes in the vehicle body speed Vb due to an operation by the driver or the like. A configuration in which only the components are subtracted is also possible.

The gain circuit 37 uses the fact that the wheel speed fluctuation amount ΔVw and the unsprung load u ₁ (ground load fluctuation) have a certain correlation, and converts the wheel speed fluctuation amount ΔVw of each wheel into the unsprung load u ₁ . Convert. Hereinafter, the relationship between the wheel speed fluctuation amount ΔVw used by the gain circuit 37 and the unsprung load u ₁ will be described.

For example, when the automobile V is traveling straight on a flat road at a constant speed, the ground contact load of the wheel 3 is constant and the wheel speed Vw is also constant. Here, in the wheel 3, the ground contact portion is deformed according to the ground load (unsprung mass M ₁ + sprung mass M ₂ ), and the dynamic load radius Rd of the tire 2 is smaller than that in the no-load state. ing. However, if the ground load increases or decreases as shown in FIG. 5B due to road surface irregularities during traveling at a speed of about 80 km / h, for example, the wheel speed is also grounded due to the change in the dynamic load radius Rd of the tire 2. Increase or decrease in accordance with the load as shown in FIG. Here, the wheel speed Vw also fluctuates at about 1 Hz, just as the ground load fluctuates at about 1 Hz due to road surface bounce. The wheel speed Vw and the ground load are both detected values by the sensor.

At this time, when the detection signals of both sensors are obtained by bandpass processing (here, passing through a bandpass filter of 0.5 to 2 Hz), the wheel speed variation ΔVw is plotted on the horizontal axis, and the ground load variation is plotted on the vertical axis. The graph taken in FIG. 6 is shown in FIG. As shown in FIG. 6, the wheel speed fluctuation amount ΔVw is proportional to the ground load fluctuation and can be expressed as the following equation.
u ₁ = kΔVw
However, k is a proportionality constant.

Therefore, the gain circuit 37 in FIG. 4 calculates the unsprung load u ₁ of each wheel by multiplying the wheel speed fluctuation amount ΔVw by a proportional constant k. That is, the gain circuit 37 functions as a basic input amount calculation unit that calculates the unsprung load u ₁ that is the basic input amount of the automobile V based on the wheel speed fluctuation amount ΔVw detected by the wheel speed sensor 9.

Thus, by performing the correction for removing the vehicle body speed Vb component from the signal of the wheel speed Vw, the wheel speed fluctuation amount ΔVw can be accurately calculated without being affected by the vehicle speed fluctuation. Further, by passing the wheel speed Vw signal to the band pass filter 36 corresponding to the sprung vibration, it is possible to calculate the unsprung load u ₁ with high accuracy based on the wheel speed variation Delta] Vw. The frequency range corresponding to the unsprung vibration is cut by the band-pass filter 36, so that the detection accuracy of the wheel speed sensor 9 and the measurement cycle / communication speed do not need to be increased more than necessary. Will improve.

(Single wheel model calculation unit 33)
The unsprung load u ₁ output from the gain circuit 37 is input to a single wheel model 38 included in the single wheel model calculation unit 33. The one-wheel model calculation unit 33 inputs the unsprung load u ₁ to the one-wheel model 38, and thereby the vehicle V of the vehicle V such as the sprung speed S ₂ and the stroke speed Ss of the suspension 7 used for the calculation in the skyhook control unit 90. Calculate and output state quantities. That is, the one-wheel model 38 constitutes a state quantity calculation unit that calculates various state quantities of the vehicle V by treating the wheel speed fluctuation amount ΔVw as an external force.

ここで、Ｍ_１：ばね下質量、Ｍ_２：ばね上質量、ｘ_１：ばね下の上下方向位置、ｘ_２：ばね上の上下方向位置、であり、ｄ^２ｘ_１／ｄｔ^２は、ばね下の上下方向加速度、ｄ^２ｘ_２／ｄｔ^２は、ばね上の上下方向加速度である。 Here, an example of the one-wheel model 38 will be described in detail. As described above, each wheel 3 of the automobile V can be expressed as shown in FIG. 2, and the following equation is obtained using the unsprung load u ₁ of the wheel 3 as an input u. It can be represented by (1). In the formulas and drawings of the present specification, the first order differential value (dx / dt) and the second order differential value (d ² x / dt ² ) are displayed as follows.

Here, M ₁ : unsprung mass, M ₂ : sprung mass, x ₁ : vertical position under the spring, x ₂ : vertical position over the spring, and d ² x ₁ / dt ² is the spring The lower vertical acceleration, d ² x ₂ / dt ^2, is the vertical acceleration on the spring.

Here, the unsprung mass M ₁ and sprung mass M ₂ are known. On the other hand, the input u, the other unsprung load u _1, although the damper 6 includes damping force u ₂ of the damper 6 from being a damping force variable, the damping force u ₂ of the damper 6 is the one wheel model 38 it can be determined based on the unsprung load u ₁ at. Therefore, if calculated on the basis of the spring under load u ₁ is the wheel speed Vw, the damping force u ₂ of the damper 6, which is calculated based on the unsprung load u ₁ and which as input u, the spring constant between the sprung and unsprung By using a system matrix that takes into account K (spring constant of the spring 5), unsprung mass M ₁ , and unsprung mass M ₂ , the unsprung and unsprung vertical accelerations d ² x ₁ / dt ² , d ² x ₂ / dt ² , unsprung position x ₁ , unsprung speed dx / dt, and the like can be obtained. Incidentally, the stroke speed Ss _is represented by _{dx 2 / dt-dx 1 /} dt.

ただし、ｕ_１：ばね下荷重、ｕ_２：ダンパ６の減衰力、Ｋ：ばね定数、である。 Specifically, M ₁ · d ² x ₁ / dt ² and M ₂ · d ² x ₂ / dt ² in the above equation (1) are expressed as the following equations (2) and (3), respectively. Can do.

However, _{u 1:} under spring load, _{u 2:} damping force of the damper 6, K: a spring constant.

ただし、ｘ：状態変数ベクトル、Ａ，Ｂ：システム行列、である。
上式（２）〜（５）から、上式（４）は下式（６）として表される。

Therefore, in the single wheel model 38, the state equation of the following equation (4) is used as a model, and the state variable x of the following equation (5) is calculated from the input vector u.

Where x: state variable vector, A, B: system matrix.
From the above formulas (2) to (5), the above formula (4) is expressed as the following formula (6).

As shown in FIG. 7, the one-wheel model 38 using such a state equation inputs the input u to the calculator 39 using the system matrix B, and integrates the output from the calculator 39 via the adder 40. The output from the integrator 41 is input to the calculator 42 using the system matrix A and returned to the adder 40. By obtaining outputs of the first to fourth observation matrices 43 to 46 from the _single wheel model 38, the unsprung position x ₁ , the sprung position x ₂ , the sprung speed S ₂ (d ² x ₂ / dt ² ), and The stroke speed Ss (d ² x ₂ / dt ² −d ² x ₁ / dt ² ) can be calculated. The first observation matrix 43 is an unsprung position observation matrix and is [1 0 0 0]. The second observation matrix 44 is a sprung position observation matrix and is [0 1 0 0]. The third observation matrix 45 is a sprung speed observation matrix and is [0 0 0 1]. The fourth observation matrix 46 is a stroke speed observation matrix and is [0 0 −1 1]. That is, the first to fourth observation matrices 43 to 46 in the single-wheel model 38 calculate the unsprung position x ₁ , the sprung position x ₂ , the sprung speed S ₂ and the stroke speed Ss based on the wheel speed fluctuation amount ΔVw, respectively. It is a means to do.

In this way, by inputting the unsprung load u ₁ calculated based on the wheel speed Vw to the one-wheel model 38, the sprung speed S ₂ and the stroke are determined regardless of whether or not the caster angle is set for the suspension 7. The speed Ss can be calculated. Since the sprung speed S ₂ and the stroke speed Ss can be calculated from the unsprung load u _1, it is not necessary to provide the vehicle V with an up / down G sensor or a stroke sensor, and the cost of the control device 20 can be reduced.

Returning again to FIG. 4, one wheel model calculation unit 33 includes a PID circuit 47 as a feedback means for feeding back the unsprung position x ₁ and the sprung position x ₂ calculated by the one-wheel model 38. As a result, the one-wheel model calculation unit 33 calculates the unsprung position x ₁ and the sprung position x ₂ calculated by the one-wheel model 38 and the unsprung reference position x ₁ o (= 0) or the sprung reference position x ₂ o ( = 0) based on a deviation between are corrected unsprung position x ₁ and the sprung position x ₂ is calculated in one-wheel model calculation unit 33, the one wheel model 38 in the steady state such as constant-speed straight running flat road sprung position x ₂ and unsprung position x ₁ is made to converge to the reference position (initial value).

As a result, the unsprung load u ₁ is adjusted with reference to the reference position, and therefore, even when the input offset to one side continues, the entire system is offset to cause an error in the sprung speed S ₂ and the stroke speed Ss. Is suppressed from occurring. In addition, data can be used on other control systems.

As described above, the one-wheel model calculation unit 33 receives the unsprung load u ₁ and the damping force u ₂ of the damper 6 as inputs, and obtains the outputs of the first observation matrix 43 and the second observation matrix 44 from the single-wheel model 38. It functions as position calculation means for calculating the lower position x ₁ and the sprung position x ₂ . Incidentally, the one wheel model calculation unit 33 here, although a form to feed back both the PID circuit 47 spring under the position x ₁ and the sprung position x _2, at least the unsprung position x ₁ and the sprung position x ₂ one was the feedback may be configured to correct the unsprung position x ₁ and the sprung position x _2. Sprung velocity S ₂ and the stroke speed Ss calculated in one-wheel model calculation unit 33, as shown in FIG. 3, is input to the skyhook control unit 90.

(Four wheel model calculation unit 34)
As shown in FIG. 4, the four-wheel model calculation unit 34 included in the state quantity calculation unit 31 includes a pitch angular velocity calculation unit 48 and a roll angular velocity calculation unit 49. The unsprung load u ₁ output from the gain circuit 37 is input to the pitch angular velocity calculation unit 48. The pitch angular velocity calculation unit 48 calculates the acceleration / deceleration (longitudinal acceleration Gx) of the vehicle V based on the input unsprung load u ₁ of each wheel (based on the wheel speed Vw), and calculates the calculated acceleration / deceleration and suspension. characteristics, determine the pitch angular velocity ωp based on such sprung mass M _2. On the other hand, the lateral acceleration Gy detected by the lateral G sensor 10 is input to the roll angular velocity calculation unit 49. Roll angular velocity calculating unit 49, and the lateral acceleration Gy inputted, the suspension characteristics, obtaining the roll angular velocity ωr based on such sprung mass M _2. As shown in FIG. 3, the pitch angular velocity ωp is input to the pitch control unit 91, and the roll angular velocity ωr is input to the roll control unit 92.

(Slip determination unit 50)
The slip determination unit 50 receives the wheel speed Vw output from the subtractor 35, that is, the deviation between the wheel speed Vw of each wheel and the estimated vehicle body speed Vb. The slip determination unit 50 determines whether or not the absolute value of the input wheel speed Vw (deviation) is greater than or equal to a predetermined value, that is, the wheel speed Vw detected by the wheel speed sensor 9 deviates from the vehicle body speed Vb by a predetermined value or more. If it is equal to or greater than a predetermined value, it is determined that the corresponding wheel 3 is in a slip state, and a slip signal SS is output. The output slip signal SS is input to a vehicle behavior control unit (not shown) that controls the ABS, TCS, and VSA. Note that when the slip signal SS is input and the ABS, TCS, or VSA is operated, the vehicle behavior control unit causes the input unit 21 to input an operation signal indicating these operations.

<Car body speed estimation unit 32>
As shown in FIG. 8, the vehicle speed estimation unit 32 in FIG. 3 includes an acceleration / deceleration force calculation unit 51 that calculates an acceleration / deceleration force F (Fe, Fs, Fd) of the vehicle V, and an acceleration / deceleration force calculation unit 51. A vehicle body speed calculation unit 52 that calculates the vehicle body speed Vb based on the speed, and correction amounts (left rear wheel turning radius ratio RR _RL , right rear wheel turning radius ratio RR _RR , left front wheel turning radius ratio described later) according to the steering operation. A steering correction amount calculation unit 53 that calculates RR _FL and a right front wheel turning radius ratio RR _FR ), and a vehicle body speed correction unit 54 that corrects the vehicle body speed Vb based on the correction amount calculated by the steering correction amount calculation unit 53. Have.

  The acceleration / deceleration force calculation unit 51 calculates an acceleration force calculation unit 55 that calculates the driving force Fe (acceleration force) of the vehicle V based on the output of a prime mover such as an engine or a motor, and a road surface gradient that calculates the deceleration force Fs of the vehicle V based on the road surface gradient. A deceleration force calculation unit 56 and a deceleration force calculation unit 57 that calculates the deceleration force Fd of the automobile V caused by factors other than the road surface gradient are included.

  The acceleration force calculation unit 55 receives the engine torque Te detected by the torque sensor and the gear position Pg as inputs, and calculates the driving force Fe of the vehicle V based on the prime mover output.

  The road surface gradient deceleration force calculation unit 56 detects, for example, the detection detected by the front and rear G sensors from the acceleration / deceleration force obtained by subtracting the deceleration force Fd calculated by the deceleration force calculation unit 57 from the driving force Fe calculated by the acceleration force calculation unit 55. By reducing the acceleration / deceleration force obtained by multiplying the longitudinal acceleration Gxd by the vehicle body weight M, the deceleration force Fs due to the road surface gradient is calculated.

  The deceleration force calculation unit 57 receives the brake fluid pressure Pb of the brake device as an input, a brake deceleration force calculation unit 58 that calculates the deceleration force of the automobile V applied to a brake operation that increases in proportion to the brake fluid pressure Pb, and a wheel speed. By using the average value of Vw as the approximate vehicle speed, a travel resistance calculation unit 59 that calculates a deceleration force applied to the travel resistance caused by the vehicle body shape and the approximate vehicle speed, and a feedback resistor that calculates a travel resistance force by wheel speed feedback A force calculating unit 60, and adding the calculation results of the brake deceleration force calculating unit 58, the running resistance calculating unit 59, and the feedback resistance force calculating unit 60 to reduce the deceleration force of the vehicle V caused by factors other than the road surface gradient. Fd is calculated.

  The vehicle body speed calculation unit 52 subtracts the deceleration force Fs calculated by the road surface gradient deceleration force calculation unit 56 from the driving force Fe calculated by the acceleration force calculation unit 55 and the deceleration force calculated by the deceleration force calculation unit 57. After the acceleration / deceleration force F of the vehicle body 1 is calculated by subtracting Fd, the acceleration / deceleration force F is divided by the vehicle body weight M to obtain an acceleration, and the vehicle speed Vb is calculated by integrating the acceleration. The calculated vehicle body speed Vb is input to the vehicle body speed correction unit 54.

Here, with reference to FIG. 9, the process in the acceleration force calculation part 55 and the deceleration force calculation part 57 is demonstrated in detail. The engine torque Te is input to the multiplier 61. The gear position Pg is input to the gear position / transmission gear ratio conversion circuit 62. The gear position-transmission gear ratio conversion circuit 62 obtains the transmission gear ratio Rg by referring to the table based on the gear position Pg and inputs the output transmission gear ratio Rg to the multiplier 61. Note that the multiplier 61 is also input the first wheel speed gain G ₁ of the first wheel speed gain setting circuit 63 to be described later.

First wheel speed gain G _1, in the first wheel speed gain setting circuit 63, that each wheel speed sensor 9 on the basis of the average wheel speed Vwav a wheel speed average value of the wheel 3 detected, referring to the reference table Is set by The first wheel speed gain G ₁ in this example is the average wheel speed Vwav of minute regions 0, the average wheel speed Vwav is substantially constant is larger than a predetermined threshold value. At the multiplier 61, the engine torque Te, the transmission gear ratio Rg and the first wheel speed gain G ₁ is multiplied is in wheel torque Tw which is the output of the driving wheels is calculated, the wheel torque Tw is torque - drive It is input to the force conversion circuit 64 and is divided by the dynamic load radius Rd of the tire 2 to be converted into the driving force Fe of the automobile V, and the output is input to the subtractor 66 through the gain circuit 65 as an added value. .

  In addition to the driving force Fe output from the gain circuit 65, the subtractor 66 receives a braking force Fb, a running resistance force Fr, and a feedback resistance force Ffb described later.

The brake fluid pressure Pb is input to the multiplier 67. The multiplier 67 also receives the second wheel speed gain G ₂ from the second wheel speed gain setting circuit 68. Second wheel speed gain G ₂ is, in the second wheel speed gain setting circuit 68, is set by referring to the reference table based on the average wheel speed Vwav. Note that the second wheel speed gain G ₂ is in this example, the average wheel speed Vwav of minute regions 0, the average wheel speed Vwav is substantially constant is larger than a predetermined threshold value. The braking force Fb is calculated from the multiplier 67 by being multiplied by the brake fluid pressure Pb and the second wheel speed gain G ₂ corresponds to the braking force by the brake device, the braking force Fb indicating a positive value, The value is input to the subtracter 66 as a subtraction value.

  The average wheel speed Vwav is input to the running resistance setting circuit 69. The running resistance force setting circuit 69 sets the running resistance force Fr depending on the vehicle speed (average wheel speed Vwav) by referring to the reference table based on the input average wheel speed Vwav. The traveling resistance force Fr indicating a positive value calculated by the traveling resistance setting circuit 69 is input to the subtractor 66 as a subtraction value.

Furthermore, the average rear wheel speed Vwav _R is the wheel speed average value of wheel 3 _R after a driven wheel is input to the feedback resistance calculating unit 60. The feedback resistance force calculation unit 60 includes a proportional circuit 72 that sets a running resistance force based on a proportional gain based on deviations ΔV obtained by subtracting the average rear wheel speed Vwav _R from the vehicle body speed Vb input to the subtractor 71, and , An integration circuit 73 for setting the running resistance force based on the integral gain, and a differentiation circuit 74 for setting the running resistance force based on the differential gain. The outputs of the proportional circuit 72, the integrating circuit 73, and the differentiating circuit 74 are input to the adder 75 and added to output a feedback resistance force Ffb that is a correction value by feedback of the vehicle body speed Vb. The output feedback resistance force Ffb is input to the subtractor 66 as a subtraction value.

  The subtractor 66 subtracts the braking force Fb, the traveling resistance force Fr, and the feedback resistance force Ffb from the driving force Fe, the deceleration force Fs due to the road gradient in FIG. 8 (not shown here), and the output acceleration / deceleration force F is obtained. The acceleration / deceleration force-acceleration / deceleration conversion circuit 76 inputs the acceleration / deceleration force F by the vehicle body weight M to convert it into the acceleration / deceleration (longitudinal acceleration Gx) of the automobile V. The acceleration / deceleration of the automobile V is input to the accumulator 78 via the gain circuit 77 and accumulated, and is output as the vehicle body speed Vb.

  Thus, the vehicle speed Vb for correcting the wheel speed Vw is obtained by calculating the vehicle speed Vb of the vehicle V based on the driving force Fe, the braking force Fb, the travel resistance force Fr, and the feedback resistance force Ffb. Can do.

Returning to FIG. 8, the steering correction amount calculation unit 53 includes a turning radius calculation unit 79 that calculates the turning radius R of the vehicle V (vehicle body 1) based on the vehicle body speed Vb and the yaw rate γ calculated by the vehicle body speed calculation unit 52. , Based on the tread T of the vehicle V, the wheel base WB, and the calculated turning radius R, the turning state amount as a correction amount, that is, the turning radius R (R _FL , R _FR , R of each vehicle body part corresponding to each wheel) _RL, left rear wheel turning radius ratio is the ratio turning radius R of the vehicle V in _{R RR) RR RL,} a right rear wheel turning radius ratio _{RR RR,} a left front wheel turning radius ratio _{RR FL} and the right front wheel turning radius ratio _{RR FR} And a wheel portion turning radius ratio calculation unit 80 to be calculated.

Hereinafter, the processing performed by the steering correction amount calculation unit 53 will be described in detail with reference to FIGS. 10 and 11. As shown in FIG. 11A, the steering correction amount calculation unit 53 turns the radii of each wheel R _FL , R _FR , R _RL , R when the vehicle V having a predetermined tread T and a wheel base WB is turning at a low speed. _The steering correction amount is calculated in consideration of the fact that _RR differs between the front and rear wheels in addition to the difference between the inner and outer wheels with respect to the turning radius R of the vehicle body 1 (that is, the turning radius R of the center of gravity of the automobile V).

ここで、自動車Ｖの旋回半径Ｒは、下式（９）で表されるため、例えば上式（７）は下式（１０）となる。
Ｒ＝Ｖ／γ ・・・（９）

Here, in order to simplify the explanation, it is assumed that the center of gravity of the automobile V is at the center of the vehicle body 1 (the center of the four wheels 3), and the automobile V has a neutral steer characteristic. Automobile V as shown in FIG. 11 (A) has left turn at a low speed, if small enough to slip angle is no or negligible occurring in the tire 2 of the wheel, the turning center of the vehicle V is of the rear wheel 3 _R axle Located on the extension line. In this case, the turning radius R _RL of the left rear wheel 3 _{RL serving as} the inner wheel is represented by the following equation (7), and the turning radius R _RR of the right rear wheel 3 _{RR serving} as the outer wheel is represented by the following equation (8).

Here, since the turning radius R of the automobile V is expressed by the following expression (9), for example, the above expression (7) becomes the following expression (10).
R = V / γ (9)

なお、後輪３_Ｒの旋回半径Ｒ_Ｒは上式で求まっているため、例えば上式（１１）に上式（１０）を代入すると、旋回半径Ｒ_ＦＬは下式（１３）となる。

On the other hand, the turning radius R _FL of the left front wheel 3 _{FL serving as} the inner wheel is represented by the following equation (11), and the turning radius R _FR of the right front wheel 3 _{FR serving} as the outer wheel is represented by the following equation (12).

Since the turning radius _{R R} of the rear wheel _{3 R} is been determined by the above equation, and substituting the above equation (10), for example, in the above equation (11), the turning radius _{R FL} becomes the following equation (13).

Thus, the turning radii R _RL of the left rear wheel 3 _RL , the right rear wheel 3 _RR , the left front wheel 3 _FL and the right front wheel 3 _{FR according} to the above formulas (7) to (9), (11) and (12), By calculating R _RR , R _FL and R _FR , the turning radius of the vehicle body part corresponding to each wheel can be calculated with high accuracy even when the geometrical influence of the tread T and the wheel base WB becomes large. The left rear wheel turning radius ratio RR _RL , the right rear wheel turning radius ratio RR _RR , the left front wheel turning radius ratio RR _FL and the right front wheel turning radius ratio RR _FR can be obtained with high accuracy.

On the other hand, when the vehicle V is turning at a medium or high speed, a slip angle is generated in the tire 2 of each wheel, so that the wheel 3 moves in a direction shifted to the outside of the turn by the slip angle with respect to the direction of the tire 2. A vehicle body slip angle that deviates to the outside of the turn with respect to the traveling direction during low-speed turning occurs. Therefore, as shown in FIG. 11 (B), the turning center of the vehicle V will be shifted forward relative amount corresponding rear wheel 3 extension of _R axle in accordance with the vehicle body slip angle. And the deviation | shift amount ahead of the turning center of the motor vehicle V becomes so large that the vehicle body speed Vb of the motor vehicle V is high, when the turning radius R of the motor vehicle V is constant. Thus, when the turning center of the automobile V deviates forward, the influence of the wheel base WB is reduced and the influence of the tread T is slightly reduced with respect to the turning radius of each wheel calculated by the above formula. Therefore, when determining the turning radius of the vehicle body part corresponding to each wheel, the wheel base WB and the tread T may be corrected according to the vehicle body speed Vb.

Rolling Also, as shown in FIG. 12 (A), even when the vehicle body slip angle in the automobile V for turning traveling at a low speed has not occurred, the rear wheel 3 _R is the front wheel 3 _F and anti-phase When being rudder, will deviate forward relative to the turning center is an extension of the axle of the rear wheel 3 _R by an amount corresponding to the actual rear wheel steering angle δra automobile V. Conversely, as shown in FIG. 12 (A), the rear wheel 3 _R is steered to the front wheel 3 _F phase with the rear by the amount pivot center of the vehicle V is in accordance with the actual rear wheel steering angle δra wheels 3 Shifts backward with respect to the extension line of the axle of _R. And the deviation | shift amount to the front of the turning center of the motor vehicle V becomes so large that the actual rear-wheel steering angle (delta) ra is large, when the turning radius R of the motor vehicle V is constant. Therefore, when obtaining the turning radius of the vehicle body part corresponding to each wheel, the wheel base WB may be corrected according to the actual rear wheel steering angle δra.

Next, processing in the steering correction amount calculation unit 53 will be described with reference to FIG. The steering correction amount calculation unit 53 uses an absolute value calculation circuit, a selection circuit, a sign setting circuit, a gain circuit, a gain setting circuit, a divider, a multiplier, a square root calculation circuit, a divider, a multiplier, a memory, and the like. A rear wheel turning radius ratio RR _RL , a right rear wheel turning radius ratio RR _RR , a left front wheel turning radius ratio RR _FL and a right front wheel turning radius ratio RR _FR are calculated. Here, all circuits and the like are not denoted by reference numerals, but only a part is denoted by reference numerals, and functions are described for each part.

  The turning radius calculation unit 79 calculates the turning radius R of the automobile V by dividing the vehicle body speed Vb by the yaw rate γ to calculate the above equation (9). At this time, the turning radius calculation unit 79 uses the detected value as it is when the absolute value of the yaw rate γ is 0.01 rad / s or more, and 0.01 rad / s when it is less than 0.01 rad / s. Use. The turning radius calculation unit 79 converts the vehicle body speed Vb from hourly speed (km / h) to second speed (m / s).

The wheel turning radius ratio calculation unit 80 is a turn of the vehicle V having a turning radius (R _FL , R _FR , R _RL , R _RR ) of each wheel, and a rear wheel turning radius calculation unit 80A, a front wheel turning radius calculation unit 80B. In addition to the turning radius ratio calculation unit 80C that calculates the turning radius ratio RR (RR _FL , RR _FR , RR _RL , RR _RR ) that is a ratio to the radius R, a wheel base correction unit that corrects the wheel base WB depending on the vehicle speed. 80D and a tread correction unit 80E that corrects the tread T depending on the vehicle speed.

The wheel base correction unit 80D includes wheel base gain setting circuits 81 and 82 and a multiplier 83. The first wheel base gain setting circuit 81, depending on the vehicle speed Vb, sets the wheelbase gain G ₃ so as to decrease the higher the vehicle speed Vb. Wheelbase gain G ₃ are when the vehicle speed Vb is small is set to 1. The second wheel base gain setting circuit 82, depending on the actual rear wheel steering angle [Delta] RA, as the actual rear wheel steering angle [Delta] RA is smaller the larger the front wheel 3 _F and the reverse phase side and the front wheel 3 _F and phase side the larger increases as establishing a wheel base gain G _4. When the actual rear wheel rudder angle δra is toe-in or toe-out, the actual rear wheel rudder angle δra of the rear wheel 3R on the outside of the turn where the ground load becomes large may be emphasized. Wheelbase gain G ₄ are in when the actual rear-wheel steering angle δra is small is set to 1. The multiplier 83 corrects the wheel base WB used for calculation of the turning radius R _F of the front wheel 3 _F by multiplying the wheel base gain G ₃ and G ₄ by the value of the wheel base WB stored in the memory.

The tread correction unit 80E includes a tread gain setting circuit 84 and a multiplier 85. Tread gain setting circuit 84, depending on the vehicle speed Vb, sets the tread gain G ₅ as vehicle speed Vb is decreased with increasing. Tread gain G ₅ when the vehicle speed Vb is small is set to 1. The multiplier 85, by multiplying the tread gain G ₅ to 1/2 of the tread T stored in the memory, the turning radius R _R of the front wheel 3 _F turning radius R _F is calculated and the rear wheel 3 _R of the The tread T (a half value) used for the calculation is corrected.

The rear wheel turning radius calculation unit 80A corrects the wheelbase based on the value obtained by squaring the turning radius R of the vehicle V calculated by the turning radius calculation unit 79 to calculate the above equations (7) and (8). By subtracting the value obtained by squaring the value of 1/2 of WB, calculating the square root of the value, and subtracting or adding 1/2 of the corrected value of the tread T to the given value , the turning radius _R RR of the right rear wheel _{3 RR} and a left rear wheel _{3 RL,} calculates the _{R RL.}

The front wheel turning radius calculation unit 80B calculates the above equations (10) and (11), the turning radius R _{RR of} the right rear wheel 3 _RR and the left rear wheel 3 _RL calculated by the rear wheel turning radius calculation unit 80A, The value obtained by squaring the value of the corrected wheelbase WB is added to the value obtained by squaring R _RL, and the square root of the value is calculated and given a sign so that the right front wheel 3 _FR and the left front wheel 3 _FL The turning radii R _FR and R _FL are calculated.

The turning radius ratio calculation unit 80C uses the turning radii R _RR , R _RL , R _FR , and R _FL of each wheel 3 calculated by the rear wheel turning radius calculation unit 80A and the front wheel turning radius calculation unit 80B as the turning radius of the vehicle V. By dividing by R, the turning radius ratio RR (RR _FL , RR _FR , RR _RL , RR _RR ) of each wheel is calculated.

The turning radius ratios RR (RR _FL , RR _FR , RR _RL , RR _RR ) calculated by the turning radius ratio calculation unit 80C are input to the vehicle speed correction unit 54 as shown in FIG. The correction unit 54 multiplies the vehicle body speed Vb and the wheel turning radius ratio RR (RR _FL , RR _FR , RR _RL , RR _RR ), respectively, so that the vehicle body speed Vb corresponding to each wheel is the left vehicle body speed Vb. A rear wheel body speed Vb _RL , a right rear wheel body speed Vb _RR , a left front wheel body speed Vb _FL and a right front wheel body speed Vb _FR are calculated.

That is, the turning radius ratio calculation unit 80C and the vehicle body speed correction unit 54 calculate the turning radius ratio RR (RR _FL , RR _FR , RR _RL , RR _RR ) of each wheel, and based on this, the influence of turning It functions as a change calculation means for calculating the vehicle body speed Vb of the vehicle body part corresponding to each wheel including the change in the wheel speed fluctuation amount ΔVw. Then, the steering correction amount calculation unit 53 and the vehicle body speed correction unit 54 correct the vehicle body speed Vb based on the turning radius ratio RR (RR _FL , RR _FR , RR _RL , RR _RR ) of each wheel, and thereby FIG. Similar to the subtractor 35 of the above, it functions as a turning influence correction unit for correcting the wheel speed Vw used to calculate the wheel speed fluctuation amount ΔVw so as to remove the change in the wheel speed fluctuation amount ΔVw due to the influence of the turning. To do.

Thus, by correcting the vehicle body speed Vb according to the turning state of the vehicle V, the vehicle body speed Vb (Vb _RL , Vb _RR) of the vehicle body part corresponding to each wheel that changes according to the steering operation of the driver. Vb _FL , Vb _FR ) are accurately calculated.

The left rear wheel body speed Vb _RL , the right rear wheel body speed Vb _RR , the left front wheel body speed Vb _FL and the right front wheel body speed Vb _FR are sent to the state quantity calculation unit 31 as shown in FIG. 36 is input as a subtraction value to a subtractor 35 provided on the upstream side of 36 to be used for calculation of the wheel speed fluctuation amount ΔVw based on the wheel speed Vw, and the vehicle body speed fluctuation component of the automobile V and the turning radius of the inner and outer wheels This is used for removing the wheel speed fluctuation component due to the difference and the difference in the trajectory length of each wheel due to the turning posture of the vehicle body 1.

In this manner, the left rear wheel vehicle speed Vb _RL , the right rear wheel vehicle speed Vb _RR , the left front wheel vehicle speed Vb _FL or the right front wheel vehicle speed Vb _FR is subtracted from each wheel speed Vw input in the state quantity calculation unit 31. it allows for the influence of longitudinal force of the motor vehicle V is excluded from the wheel speed Vw, the state quantity of the motor vehicle V (sprung speed S ₂ and the stroke speed Ss) is calculated with higher accuracy. Further, the vehicle body speed correction unit 54 corrects the vehicle body speed Vb based on the turning radius ratio RR (RR _FL , RR _FR , RR _RL , RR _RR ) of each wheel, so that the vehicle body speed Vb corresponding to each wheel is obtained. Since the calculation is performed with high accuracy and the influence on the wheel speed Vw due to the turning of the vehicle V is eliminated, the state quantity of the vehicle V is calculated with higher accuracy even during the low-speed turning.

In particular, the front wheel turning radius calculating section 80B is, the turning radius _{R FL} of the front wheel _{3 F} using wheelbase WB corrected by the wheelbase gain _G 3, _{G 4} that depends on the vehicle speed Vb and the actual rear wheel steering angle [Delta] RA, to calculate the R _FR, due to the turning center in dependence on the vehicle speed Vb and the actual rear wheel steering angle δra moves, the front wheel 3 _F turning radius R _FL of _the effect of wheel base WB spanning R _FR Is removed. Therefore, the turning radii R _FL and R _{FR of} the front wheels 3 _F are calculated with higher accuracy, and the state quantity (sprung speed S ₂ and stroke speed Ss) of the vehicle V is calculated with higher accuracy than when turning at low speed. The

Further, the rear wheel turning radius calculating section 80A comprises a turning radius R of the vehicle body 1, a tread T corrected by the tread gain G ₅ that depends on the vehicle speed Vb, depends on the vehicle speed Vb and the actual rear wheel steering angle δra Since the turning radii R _RR and R _RL of the rear wheel 3 _R are calculated using the wheel base WB corrected with the wheel base gains G ₃ and G ₄ , the turning center moves depending on the vehicle body speed Vb. As a result, the change in the influence of the tread T and the wheel base WB on the turning radii R _RR and R _RL of the rear wheel 3 _R is removed. Therefore, the turning radii R _RR and R _{RL of} the rear wheel 3 _R are calculated with higher accuracy, and the state quantity (sprung speed S ₂ and stroke speed Ss) of the vehicle V is calculated with higher accuracy.

Figure 13 (A) is a time chart showing the sprung speed detected by using a sensor, and a state quantity calculation unit 31 sprung speed S ₂ calculated by the dashed line and each solid line in FIG. 13 (B ) Is a time chart in which the stroke speed detected using the sensor and the stroke speed Ss calculated by the state quantity calculation unit 31 are indicated by a broken line and a solid line, respectively. As shown in FIG. 13, the calculated stroke speed Ss and sprung speed S ₂ substantially match the sensor value, and the state quantity calculation unit 31 determines the stroke speed Ss and sprung speed S based on the wheel speed Vw. ₂ can be calculated with high accuracy. Further, in the present embodiment calculates the unsprung load u _1, based on the wheel speed Vw, to the unsprung load u ₁ to the input of the vehicle model, whether or caster angle to a suspension 7 is set not, it is possible to calculate the sprung speed S ₂ and the stroke speed Ss.

<Control target current setting unit 23>
As shown in FIG. 3, the control target current setting unit 23 performs skyhook control, performs a skyhook control unit 90 that sets the skyhook control target current Ash, and performs pitch control based on the pitch angular velocity ωp, thereby performing a pitch control target. Pitch control unit 91 for setting current Ap, roll control based on roll angular velocity ωr, roll control unit 92 for setting roll control target current Ar, roll control based on steering steering angle δf, and steering angle proportional control target current The steering angle proportional control unit 93 for setting Asa, the unsprung vibration control of the automobile V, the unsprung vibration control unit 95 for setting the unsprung vibration control target current Au, and the minimum damping force depending on the vehicle speed. A minimum target current control unit 96 that sets a minimum target current Amin to be generated is included.

  The skyhook control unit 90 performs ride comfort control (vibration suppression control) that suppresses vehicle shake when overcoming road surface irregularities and enhances ride comfort. The pitch control unit 91 performs body posture control that optimizes the posture of the vehicle body 1 by suppressing pitching during rapid acceleration or sudden deceleration of the vehicle V. A roll posture control unit 94 including a roll control unit 92 and a steering angle proportional control unit 93 performs vehicle body posture control that suppresses rolling during turning of the vehicle V and optimizes the posture of the vehicle body 1. The unsprung vibration suppression control unit 95 suppresses vibrations in the unsprung resonance region and improves the grounding property and riding comfort of the wheel 3.

<Skyhook control unit 90>
Next, processing in the skyhook control unit 90 will be described in detail with reference to FIGS. 14 and 15. In the skyhook control unit 90, the sprung speed S ₂ calculated by the state quantity calculation unit 31 in FIG. 3 is input to the damping force base value calculation unit 97. Damping force base value calculation section 97, based on the sprung speed S ₂ inputted, the spring - setting the damping force base value Dsb by referring to damping force map. The set damping force base value Dsb is input to the gain circuit 98. In the gain circuit 98, the skyhook target damping force Dsht is calculated by multiplying the damping force base value Dsb by the skyhook gain Gsh, and the calculated target damping force Dsht is input to the target current setting circuit 99. A stroke speed Ss is also input to the target current setting circuit 99. The target current setting circuit 99 refers to the current map shown in FIG. 15 based on the skyhook target damping force Dsht and the stroke speed Ss. The skyhook control target current Ash for the damper 6 is set, and the skyhook control target current Ash is output.

<Unsprung vibration suppression control unit 95>
Next, the unsprung vibration suppression control unit 95 of FIG. 3 will be described in detail with reference to FIGS. As shown in FIG. 16, the unsprung vibration suppression control unit 95 inputs each wheel speed Vw input to the bandpass filter 101. The band-pass filter 101 has a band-pass characteristic of 8 to 18 Hz in order to pass the wheel speed Vw signal in the unsprung resonance region. Therefore, the band pass filter 101 extracts a signal in a frequency range higher than the frequency range of 0.5 to 5 Hz of the band pass filter 36 (FIG. 4) for skyhook control. The cut frequency on the high frequency side of the band pass filter 36 for skyhook control is 5 Hz, the cut frequency on the low frequency side of the band pass filter 101 for unsprung vibration suppression control is 8 Hz, and both bandpass Since the band gap is provided between the filters 36 and 101, mutual interference due to skyhook control and unsprung vibration suppression control is prevented.

  The wheel speed Vw signal input from the CAN 16 includes signals other than the unsprung resonance region. For example, the wheel speed Vw signal having a frequency characteristic shown in FIG. The wheel speed Vw signal in the unsprung resonance region as shown in FIG. 17B is included. Therefore, by passing the wheel speed Vw signal through the bandpass filter 101 corresponding to the unsprung resonance region, the wheel speed Vw signal including the unsprung signal component is extracted, and the DC component is removed from the wheel speed Vw signal. be able to. That is, the bandpass filter 101 functions as a wheel speed fluctuation amount extracting unit that extracts the wheel speed fluctuation amount ΔVw based on the wheel speed Vw signal.

The wheel speed fluctuation amount ΔVw that has passed through the bandpass filter 101 is input to the absolute value calculation circuit 102 and converted into an absolute value of the wheel speed fluctuation amount ΔVw. Wheel speed variation ΔVw is proportional to the unsprung load u ₁ as described above, the vertical acceleration of the unsprung which is obtained by dividing the unsprung load u ₁ in unsprung mass M ₁ also corresponds to the wheel speed variation ΔVw It becomes the value. Therefore, unsprung vibration can be suppressed by generating a damping force corresponding to the absolute value of the vertical acceleration.

The wheel speed fluctuation amount ΔVw output from the absolute value calculation circuit 102 is input to the gain circuit 103 and multiplied by the gain, whereby the magnitude (absolute value) of the unsprung acceleration Gz ₁ that is the basic input amount of the automobile V. Is calculated. Specifically, the gain circuit 103 multiplies the wheel speed variation ΔVw a value obtained by dividing the unsprung mass M ₁ of the proportionality constant k described in relation to FIG. 6 as the gain.

The unsprung acceleration Gz ₁ output from the gain circuit 103 is input to the target current setting circuit 104. The target current setting circuit 104, calculates current is calculated corresponding to the unsprung acceleration Gz _1, unsprung vibration suppression control target current Au by the peak hold ramp down control based on the calculated current is set.

The target current setting circuit 104 responds to the input of the unsprung acceleration Gz _{1 having} the characteristics shown in FIG. 18A based on the calculated current indicated by the broken line in FIG. 18B and the solid line in FIG. The unsprung vibration suppression control target current Au as shown is set. Specifically, the target current setting circuit 104 holds the maximum value of the input calculated current as the unsprung vibration suppression control target current Au for a predetermined time, and after the predetermined time has elapsed since the input of the maximum value. Then, the value of the unsprung vibration suppression control target current Au is decreased with a predetermined gradient. That is, when the unsprung acceleration Gz ₁ is increased in accordance with the unsprung acceleration Gz ₁ (fast) while setting the value of the unsprung vibration suppression control target current Au to respond, the unsprung acceleration Gz ₁ In the case of reduction, the response is set slower than in the case of increase. As a result, the unsprung vibration is attenuated more effectively and stably than when the calculated current as shown by the broken line is set to the unsprung vibration suppression control target current Au.

  Returning to FIG. 16, the unsprung vibration suppression control target current Au output from the target current setting circuit 104 is input to the limiting circuit 105. The limit circuit 105 limits the upper limit of the unsprung vibration suppression control target current Au to the upper limit value Aumax and outputs the unsprung vibration suppression control target current Au. That is, the limit circuit 105 sets the upper limit value Aumax to the unsprung vibration suppression control target current Au when the input unsprung vibration suppression control target current Au exceeds the upper limit value Aumax. Thereby, the unsprung vibration suppression control target current Au set according to the magnitude of the wheel speed fluctuation amount ΔVw becomes the upper limit value Aumax set in consideration of the power supply capacity of the vehicle V and the damping force characteristics of the damper 6. It is prevented that the setting is exceeded.

  The wheel speed fluctuation amount ΔVw output from the absolute value calculation circuit 102 is input not only to the gain circuit 103 but also to the low-pass filter 106. Here, the low-pass filter 106 has a low-pass characteristic that allows a band lower than 1 Hz to pass. The upper limit setting circuit 107 sets the upper limit value Aumax according to the absolute value of the wheel speed fluctuation amount ΔVw that has passed through the low-pass filter 106 and causes the upper limit value Aumax to be input to the limit circuit 105. Specifically, the upper limit setting circuit 107 sets the upper limit value Aumax so that the wheel speed fluctuation amount ΔVw decreases as the wheel speed fluctuation amount ΔVw increases when the absolute value of the wheel speed fluctuation amount ΔVw exceeds a predetermined value.

  The limit circuit 105 changes the upper limit of the unsprung vibration suppression control target current Au according to the input upper limit value Aumax, that is, the upper limit value Aumax decreases as the absolute value of the wheel speed fluctuation amount ΔVw passing through the low-pass filter 106 increases. Change to The effect will be described below.

  On a relatively flat pavement, the wheel speed fluctuation amount ΔVw (absolute value) after passing through the low-pass filter 106 indicated by a solid line in FIG. 19A is compared with the wheel speed fluctuation amount ΔVw before passing through the low-pass filter 106 indicated by a thin line. The average value is also small. On the other hand, in rough pavement, as shown in FIG. 19B, the wheel speed fluctuation amount ΔVw before passing through the low-pass filter 106 indicated by a thin line is not only larger than the flat road of (A), but also a solid line. The wheel speed fluctuation amount ΔVw after passing through the low-pass filter 106 is also larger than (A). Therefore, when the absolute value of the wheel speed fluctuation amount ΔVw that has passed through the low-pass filter 106 is large, it is assumed that the road surface is rough, and the limiting circuit 105 reduces the unsprung vibration suppression control target current Au (unsprung vibration damping). By weakening the control), it is possible to prevent the ride comfort from being deteriorated by setting the lower vibration suppression control target current Au to be excessively high.

  Thus, the unsprung vibration suppression control unit 95 can be configured to set the unsprung vibration suppression control target current Au based on the wheel speed Vw signal. Since the determination is based on the wheel speed fluctuation amount ΔVw of the unsprung resonance region component of Vw, the unsprung vibration suppression control can be performed without intervening other factors such as the sprung.

<Current fixing unit 24>
Returning to FIG. 3, when any of the operation signals indicating that VSA, ABS, and TCS are operating is input to the input unit 21, the current fixing unit 24 has an unstable behavior of the vehicle V. As a thing, the electric current fixed signal Sfix is output. The output current fixing signal Sfix is input to the damper control unit 25.

<Damper control unit 25>
The damper control unit 25 includes a high current selection unit 108 and a current control unit 109. The high current selection unit 108 sets the set skyhook control target current Ash, pitch control target current Ap, roll control target current Ar, steering angle proportional control target current Asa, unsprung vibration suppression control target current Au, and minimum target current Amin. The largest value is set as the target current Atgt.

  A target current Atgt and a current fixing signal Sfix are input to the current control unit 109. When the current fixing signal Sfix is not input, the current control unit 109 generates a drive current to each damper 6 based on the target current Atgt set by the high current selection unit 108 and controls the damping force of the damper 6. . On the other hand, when the current fixing signal Sfix is input, the current control unit 109 fixes the current based on the target current Atgt immediately before the current fixing signal Sfix is input in order to avoid a sudden change in the damping force of the damper 6. (That is, the damping coefficient of the damper 6 is fixed to a predetermined value), a driving current to each damper 6 is generated based on the fixed target current Atgt, and the damping force of the damper 6 is controlled.

  Here, the current control unit 109 maintains the target current Atgt constant over a period during which the current fixing signal Sfix is input. Alternatively, the target current Atgt may be maintained constant until a predetermined time elapses after the input of the current fixing signal Sfix is lost.

≪Damping force control procedure≫
The ECU 8 configured in this way performs damping force control according to the following basic procedure. That is, when the automobile V starts running, the ECU 8 executes damping force control whose procedure is shown in the flowchart of FIG. 20 at a predetermined processing interval (for example, 10 ms). When the damping force control is started, the ECU 8 calculates the unsprung load u ₁ of each wheel based on the detected value of the wheel speed sensor 9 and the calculated unsprung load u ₁ and the detected value of the lateral G sensor 10. based on calculates motion state quantity of the motor vehicle V (sprung speed S ₂ and the stroke speed Ss of each wheel, the roll angular velocity ωr of the vehicle body 1, the pitch angular velocity .omega.p) (steps ST1).

Then, ECU 8, based on the sprung speed _{S 2} and the stroke speed Ss is calculated skyhook control target current Ash of each damper 6 (step ST2), the pitch of the dampers 6 based on the pitch angular velocity ωp of the vehicle body 1 The control target current Ap is calculated (step ST3), the roll control target current Ar of each damper 6 is calculated based on the roll angular velocity ωr of the vehicle body 1 (step ST4), and the steering of each damper 6 is calculated based on the steering steering angle δf. The angular proportional control target current Asa is calculated (step ST5), and the unsprung vibration suppression control target current Au of each damper 6 is calculated based on the wheel speed Vw of each wheel (step ST6), and the wheel speed Vw of each wheel is calculated. Based on this, the minimum target current Amin of each damper 6 is calculated (step ST7). Note that the processes of steps ST2 to ST7 do not have to be performed in this order, or may be performed in parallel.

  Next, the ECU 8 sets the largest value among the six control target currents Ash, Ap, Ar, Asa, Au, and Amin for each wheel as the target current Atgt (step ST8). Thereafter, the ECU 8 determines whether or not the current fixing signal Sfix is input (step ST9), and when this determination is No (that is, when any of VSA, ABS, and TCS is not operating), Based on the target current Atgt selected in step ST8, a drive current is output to the MLV coil of each damper 6 (step ST10). Thereby, in damping force control, the optimal target damping force according to the load of the damper 6 is set, and improvement in steering stability and riding comfort is realized.

  On the other hand, when the determination in step ST9 is Yes (that is, when any of VSA, ABS, and TCS is operating), the ECU 8 applies the MLV coil of each damper 6 based on the target current Atgt of the previous value. A drive current is output (step ST11). As a result, when any one of VSA, ABS, and TCS is operating, the target current Atgt selected in step ST8 is prevented from changing suddenly and the vehicle behavior becoming unstable.

  Although the description of the specific embodiment is finished as described above, the present invention is not limited to the above embodiment and can be widely modified. For example, in the above embodiment, the wheel speed Vw before the calculation of the wheel speed fluctuation amount ΔVw is corrected so as to remove the change due to the influence of the steering, but the wheel speed fluctuation amount ΔVw is directly corrected. You may make it correct | amend. In addition, the specific configuration and arrangement of each member and part, or the specific procedure of control can be changed as appropriate without departing from the spirit of the present invention. On the other hand, all the components of the control device for the damping force variable damper according to the present invention shown in the above embodiment are not necessarily essential, and can be appropriately selected.

V Automobile (vehicle)
1 Body 3 Wheel 6 Damper (Damping Force Variable Damper)
8 ECU
9 Wheel speed sensor 14 Rear wheel steering device 20 Control device 23 Control target current setting unit (control means)
25 Damper control unit (control means)
33 One-wheel model calculation part (state quantity calculation means)
35 Subtractor (steering influence correction means)
36 Bandpass filter (wheel speed fluctuation calculation means)
53 Steering correction amount calculation unit (steering influence correction means)
54 Vehicle body speed correction unit (steering influence correction means, change calculation means))
80A Rear wheel turning radius calculation unit (rear wheel turning radius calculation means)
80B Front wheel turning radius calculation unit (front wheel turning radius calculation means)
80C turning radius ratio calculation part (change calculation means)
80D Wheel base correction unit 80E Tread correction unit G ₃ Wheel base gain G ₄ Wheel base gain G ₅ Tread gain R Turning radius of automobile V (body 1) R _FR Turning radius of right front wheel R _FL Turning radius of left front wheel RR _FL Left Front wheel turning radius ratio RR _FR Right front wheel turning radius ratio Vw Wheel speed ΔVw Wheel speed fluctuation amount Vb Body speed Vb _FL Left front wheel body speed (change in wheel speed fluctuation due to the effect of steering)
Vb _FR right front wheel body speed (change in wheel speed fluctuation due to steering)
S ₂ Sprung speed (state quantity)
Ss Stroke speed (state quantity)
T tread WB wheelbase δra actual rear wheel rudder angle

Claims (6)

A wheel speed sensor for detecting the wheel speed of each wheel;
Wheel speed fluctuation amount calculating means for calculating a wheel speed fluctuation amount based on a wheel speed detection value detected by the wheel speed sensor;
State quantity calculating means for calculating a vehicle state quantity including at least one of the sprung speed of the vehicle body and the stroke speed of the suspension based on the wheel speed fluctuation amount;
A damping force variable damper control device comprising: control means for controlling a damping force of the damping force variable damper based on at least one of the sprung speed and the stroke speed calculated by the state quantity calculating means;
A steering influence correction unit for correcting the wheel speed fluctuation amount so as to remove the change in the wheel speed fluctuation amount due to the influence of the steering;
The steering influence correction means is
A rear wheel turning radius calculating means for calculating a turning radius of the right rear wheel and the left rear wheel;
Front wheel turning radius calculating means for calculating the turning radius of the right front wheel and the left front wheel using the calculated turning radius and wheel base of the right rear wheel and the left rear wheel;
A change amount calculating means for calculating a change amount of the wheel speed fluctuation amount due to the influence of the steering based on a front wheel turning radius ratio which is a ratio of a turning radius of the right front wheel and a turning radius of the left front wheel to a turning radius of a vehicle body; A damping force variable damper control device comprising:   2. The damping force according to claim 1, wherein the front wheel turning radius calculation means calculates the turning radius of the right front wheel and the left front wheel using a value obtained by correcting the wheel base depending on a vehicle speed. Control device for variable damper.   The rear wheel turning radius calculating means calculates the turning radius of the right rear wheel and the left rear wheel using the vehicle body turning radius, the tread, and a value obtained by correcting the wheel base depending on the vehicle speed. The control device for a damping force variable damper according to claim 1 or 2, characterized in that   The said rear-wheel turning radius calculation means calculates the turning radius of the said right rear wheel and the said left rear wheel using the value which corrected the said tread depending on the vehicle speed. Control device for variable damping force damper. The vehicle includes a rear wheel steering device for changing a toe angle of a rear wheel;
2. The front wheel turning radius calculation means calculates a turning radius of the right front wheel and the left front wheel using a value obtained by correcting the wheel base depending on a steering angle of the rear wheel. The control apparatus of the damping force variable damper as described in any one of Claims 4-5.   The rear wheel turning radius calculating means calculates the turning radius of the right front wheel and the left front wheel using a value obtained by correcting the vehicle body turning radius, the tread, and the wheel base depending on a steering angle of the rear wheel. The damping force variable damper control device according to claim 5, wherein the damping force variable damper is calculated.

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