JP2019189228A - Suspension control device - Google Patents

Abstract

To improve riding comfort without using an expensive sensor such as a stroke sensor.SOLUTION: A suspension control device includes: a wheel speed sensor which detects wheel speed of each wheel; basic input amount calculation means which calculates basic input amount of a vehicle on the basis of wheel speed variation detected by the wheel speed sensor; state amount calculation means which calculates state amount of the vehicle by inputting the basic input amount into a vehicle model indicating a behavior of the vehicle; and damper control means which controls damping force of a damping force variable damper on the basis of the calculated state amount. When a value of the wheel speed variation detected by the wheel speed sensor becomes a prescribed value or more to a minus side by defining zero as a reference, control to increase the damping force is performed by regarding that a ground load of the wheel is reduced, and the damping force of the damping force variable damper provided in each of right and left front wheels is controlled on the basis of the state amount in the wheel having larger wheel speed variation of the right and left front wheels.SELECTED DRAWING: Figure 7

Description

  The present invention relates to a vehicle suspension control apparatus having a damping force variable damper whose damping force can be adjusted in response to an input signal.

  For example, Patent Document 1 discloses a vehicle control device that controls the attitude of a vehicle without using an expensive sensor such as a sprung vertical acceleration sensor or a stroke sensor. In this vehicle control device, the sprung speed is estimated based on the wheel speed, and the control amounts of a plurality of actuators that achieve the target posture are calculated.

International Publication No. 2013/115006

  By the way, as one means for improving the riding comfort of the vehicle, a method of performing skyhook control or the like by estimating the vehicle vertical state amount necessary for the variable damper control from the wheel speed signal is conceivable. However, with this control method, it is difficult to estimate the absolute amount of the suspension stroke, or the calculation accuracy of the estimated absolute amount is reduced, and for example, the damping force is increased when approaching the vicinity of the full stroke. The increasing control cannot be performed accurately.

  Note that in a control system including a stroke sensor, it is possible to perform control to increase the damping force of the suspension when approaching the vicinity of the full stroke based on the value of the suspension stroke detected by the stroke sensor.

  On the other hand, the conventional control system that does not have a stroke sensor cannot perform the above-mentioned control, so shock G and shock noise are generated due to full rebound shock and push-up by full bump after full rebound. To do. As a result, the occupant feels uncomfortable and ride comfort and merchantability are reduced.

  The present invention has been made in view of the above points, and an object thereof is to provide a suspension control device capable of improving riding comfort without using an expensive sensor such as a stroke sensor. To do.

  In order to achieve the above object, the present invention provides a suspension control device for a vehicle having a damping force variable damper whose damping force can be adjusted in response to an input signal, and for detecting the wheel speed of each wheel. A basic input amount calculating means for calculating a basic input amount of the vehicle based on a wheel speed variation detected by the wheel speed sensor; and inputting the basic input amount into a vehicle model representing the behavior of the vehicle. A state quantity calculating means for calculating the state quantity of the vehicle, and a damper control means for controlling the damping force of the variable damping force damper based on the calculated state quantity, and detected by the wheel speed sensor. When the value of the wheel speed fluctuation becomes a predetermined value or more on the minus side with reference to zero, the damper control means increases the damping force as compared to before the value of the wheel speed fluctuation exceeds the predetermined value. The damper control means controls the damping force of the damping force variable damper provided in each of the left and right front wheels based on the state quantity having the larger wheel speed fluctuation in the left and right front wheels. And

  Further, the present invention is characterized in that the damper control means increases the damping force before reaching full rebound.

  A suspension control device capable of improving riding comfort without using an expensive sensor such as a stroke sensor can be obtained.

1 is a schematic configuration diagram of a vehicle to which a suspension control device according to an embodiment of the present invention is applied. It is a schematic diagram of the suspension shown in FIG. 1 is a block diagram showing a schematic configuration of a suspension control device according to an embodiment of the present invention. It is a block diagram of the state quantity calculation part shown in FIG. It is a block diagram of the skyhook control part shown in FIG. FIG. 6 is a target current map diagram used by the target current setting circuit shown in FIG. 5. (A) is a characteristic diagram showing the correlation between time (t) on the horizontal axis and wheel speed fluctuation (km / h) on the vertical axis, and (b) is the attenuation on the horizontal axis (t) and the vertical axis. FIG. 5C is a characteristic diagram showing a correlation between time (t) on the horizontal axis and sprung G (m / sec ² ) on the vertical axis. (A) is an explanatory view showing a state in which the right front wheel rides on a protrusion on the road surface, (b) is an explanatory view showing a state of full rebound after the right front wheel gets over the protrusion on the road surface, (c) It is explanatory drawing which shows the state which the right front wheel landed on the road surface after full rebound. (A), (b) is a characteristic view which shows the 1st example of control of damping force. (A), (b) is a characteristic view which shows the 2nd example of control of damping force. (A), (b) is a characteristic view which shows the 3rd example of control of damping force. (A), (b) is a characteristic view which shows the 4th example of control of damping force.

  Next, embodiments of the present invention will be described in detail with reference to the drawings as appropriate. 1 is a schematic configuration diagram of a vehicle to which a suspension control device according to an embodiment of the present invention is applied, FIG. 2 is a schematic diagram of the suspension shown in FIG. 1, and FIG. 3 is a suspension control according to the embodiment of the present invention. FIG. 4 is a block diagram of the state quantity calculation unit shown in FIG. 3.

  As shown in FIGS. 1 and 2, the vehicle body 12 of the automobile (vehicle) 10 has four wheels 16 on which tires 14 are mounted in the front, rear, left and right. Each wheel 16 is suspended from the vehicle body 12 via a suspension composed of a suspension arm 18, a spring 20, a damping force variable damper 22 (hereinafter simply referred to as a damper 22), and the like. The automobile 10 includes an ECU (Electronic Control Unit) 24 that performs various controls, and a wheel speed sensor 26 that is disposed for each wheel and detects the wheel speed V of each wheel 16. The wheel speed sensor 26 detects the rotational speed of each wheel 16 as a detection signal (also referred to as a wheel speed signal). The automobile 10 may be any of a front wheel drive vehicle, a rear wheel drive vehicle, and a four wheel drive vehicle.

  The ECU 24 includes a microcomputer, a ROM, a RAM, a peripheral circuit, an input / output interface, various drivers, and the like. The ECU 24 is electrically connected to the damper 22 and the wheel speed sensor 26 of each wheel 16 via a communication line (CAN (Controller Area Network) 28 in this embodiment). The ECU 24 and the wheel speed sensor 26 constitute a suspension control device.

  In the present embodiment, the damper 22 is configured by, for example, a monotube type (de-carbon type) damper. The damper 22 is mounted so that the piston rod can slide along the axial direction with respect to a cylindrical cylinder filled with magneto-rheological fluid (MRF), and is attached to the tip of the piston rod. The piston divides the inside of the cylinder into an upper oil chamber and a lower oil chamber. A communication passage is provided between the upper oil chamber and the lower oil chamber to connect the upper oil chamber and the lower oil chamber. An MLV coil is disposed inside the communication path.

  In the damper 22, for example, the lower end of a cylinder is connected to a suspension arm 18 that is a wheel side member, and the upper end of a piston rod is connected to a damper base that is a vehicle body side member. As shown in FIG. 2, each damper 22 has an unsprung element having a mass M <b> 1 (a movable element below the suspension including the wheel 16, knuckle, suspension arm 18, etc.) and a mass M <b> 2 made of the vehicle body 12. A sprung element is connected to the spring 20 together.

  When a current is supplied from the ECU 24 to an MLV coil (not shown) of the damper 22, 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 22 increases.

Next, description will be made based on the block diagram shown in FIG.
The ECU 24 includes a wheel speed sensor 26 that is electrically connected to the CAN 28, a vehicle state quantity estimation unit 30 that estimates a vehicle vertical state quantity of the automobile 10 from a detection signal of the wheel speed sensor 26, and a vehicle state quantity estimation unit 30. A control target current setting unit 32 that sets a control target current of each damper 22 from the various calculated values and detection signals of the wheel speed sensor 26 in order to improve the steering stability and ride comfort of the automobile 10, and the control target And a damper control unit that generates a drive current to the damper 22 based on the control target current set by the current setting unit 32 and controls the damping force of the damper 22.

  Each wheel speed signal output from the wheel speed sensor 26 of each wheel 16 is input to the state quantity calculation unit 36 of the vehicle state quantity estimation unit 30. The damping force control for the left and right rear wheels is performed after a predetermined time difference (time lag) after performing the damping force control for the left and right front wheels. Further, control is performed between the left front wheel and the right front wheel based on the larger attenuation amount. As a result, the state quantity calculation unit 36 selects the larger wheel speed fluctuation among the wheel speed fluctuations of the left and right front wheels, and calculates by the one-wheel model calculation section 38 described later based on the selected wheel speed fluctuation. Is done.

  The vehicle state quantity estimation unit 30 estimates the state quantity of the automobile 10 by utilizing the fact that the wheel speed fluctuation has a certain relationship with the ground load on the road surface of the wheel 16. The vehicle state quantity estimation unit 30 includes a state quantity calculation unit 36 that estimates various state quantities of the automobile 10 for each wheel 16 using a vehicle model based on the detection value of the wheel speed sensor 26. The state quantity calculation unit 36 includes a single wheel model calculation unit 38 for each of the front, rear, left and right wheels.

Hereinafter, the state quantity calculation unit 36 will be described in detail.
As shown in FIG. 4, in the state quantity calculation unit 36, the wheel speed signal output from the wheel speed sensor 26 is input to the gain circuit 42 via the bandpass filter 40. The bandpass filter 40 has a bandpass characteristic that allows a frequency component of 0.5 to 5 Hz to pass through, for example. In the present embodiment, the CAN 28 is used as the communication line, and the wheel speed signal is input at an update period of about 10 to 20 msec. Therefore, the bandpass filter 40 blocks the high frequency component and the frequency component of the sprung resonance band. It functions as a low-pass filter that passes a band lower than about 5 Hz so that (a signal in a frequency range corresponding to the sprung vibration) can be reliably extracted. When the wheel speed signal is input at a shorter update cycle, for example, a bandpass filter 40 having a high band of about 20 Hz is used so that the frequency component of the unsprung resonance band can be extracted. Also good.

  The gain circuit 42 calculates the unsprung load (ground load) based on the wheel speed variation of each wheel 16 by utilizing the proportional relationship between the wheel speed variation and the unsprung load U1 (contact load). That is, the gain circuit 42 calculates the ground load of each wheel 16 by multiplying the wheel speed variation by the proportional constant k. As a result, the gain circuit 42 functions as basic input amount calculation means for calculating an unsprung load (ground load) that is a basic input amount of the automobile 10 based on wheel speed fluctuations.

  The unsprung load (ground load) output from the gain circuit 42 is input to a single wheel model included in the single wheel model calculation unit 38. The one-wheel model calculation unit 38 calculates the state quantity of the vehicle 10 including the sprung speed and suspension stroke speed used for calculation in the skyhook control unit 44 described later by inputting the unsprung load to the one-wheel model. ·Output. That is, the single-wheel model calculation unit 38 functions as a state quantity calculation unit that calculates various state quantities of the automobile 10 by treating the wheel speed fluctuation as an external force.

  The control target current setting unit 32 includes a skyhook control unit 44. The skyhook control unit 44 performs skyhook control and sets a skyhook control target current. FIG. 5 is a block diagram of the skyhook controller shown in FIG. 3, and FIG. 6 is a target current map used by the target current setting circuit shown in FIG. Hereinafter, based on FIG. 5, the process in the skyhook control part 44 is demonstrated in detail.

  In the skyhook controller 44, the sprung speed calculated by the state quantity calculator 36 is input to the damping force base value calculator 46. The damping force base value calculation unit 46 calculates the damping force base value by referring to the sprung-damping force map based on the input sprung speed. The calculated damping force base value is input to the gain circuit 48. In the gain circuit 48, the skyhook target damping force is calculated by multiplying the damping force base value by the skyhook gain. The calculated skyhook target damping force is input to the target current setting circuit 50. A stroke speed Ss is also input to the target current setting circuit 50. The target current setting circuit 50 sets the skyhook control target current for each damper 22 by referring to the current map 52 (0A to 6A) shown in FIG. 6 based on the skyhook target damping force and the stroke speed Ss. And output the skyhook control target current.

  Returning to FIG. 3, the damper control unit 34 includes a damping force control unit 54 that controls the damping force of the suspension. The damping force control unit 54 includes a peak hold unit 56 that holds the increased damping force at a predetermined peak value, a peak hold time adjustment unit 58 that adjusts the peak hold time of the damping force, and a control that adjusts the control gain G. A gain adjustment unit 60 and a threshold adjustment unit 62 that adjusts a threshold value of the damping force are included.

  The ECU 24 includes a minus side determination unit 64 to which a wheel speed signal detected by the wheel speed sensor 26 is input. The minus side determination unit 64 obtains the wheel speed fluctuation per unit time based on the wheel speed signal of the wheel speed sensor 26, and judges whether or not the wheel speed fluctuation has decreased by a predetermined value or more on the minus side with reference to zero. To do. When the minus side determination unit 64 determines that the wheel speed fluctuation exceeds zero and decreases by a predetermined value or more, it outputs a control signal to the damping force control unit 54, compared with before the wheel speed fluctuation exceeds the predetermined value. Control to increase the damping force of the suspension. This will be described in detail later.

  The automobile 10 to which the suspension control device according to the present embodiment is applied is basically configured as described above, and the function and effect thereof will be described next.

First, the basic principle of the present invention will be described with reference to FIGS. FIG. 7A is a characteristic diagram showing the correlation between the time (t) on the horizontal axis and the wheel speed fluctuation (km / h) on the vertical axis, and FIG. 7B shows the time (t) on the horizontal axis. FIG. 7C is a characteristic diagram showing a correlation between time (t) on the horizontal axis and sprung G (m / sec ² ) on the vertical axis. is there.

  The present invention obtains a wheel speed fluctuation per unit time based on the wheel speed V detected by the wheel speed sensor 26, and when the wheel speed fluctuation becomes a predetermined value or more on the minus side with reference to zero, the wheel 16 It is characterized in that control for increasing the damping force of the suspension is performed as compared with before the wheel speed fluctuation exceeds a predetermined value. That is, in the present invention, it is found that a substantially proportional relationship is established between the wheel speed fluctuation and the ground load, and the wheel speed fluctuation is not converted (calculated) into the ground load as in the conventional case. Suspension control is simplified by considering the decrease in wheel load as a decrease in wheel ground contact load.

  Based on FIG. 8 (a)-(c), it demonstrates concretely below. FIG. 8A is an explanatory view showing a state where the right front wheel rides on a protrusion on the road surface, and FIG. 8B is an explanatory view showing a state of full rebound after the right front wheel gets over the protrusion on the road surface. 8 (c) is an explanatory diagram showing a state where the right front wheel has landed on the road surface after full rebound.

  When the vehicle 10 starts normal travel, the ECU 24 executes normal suspension damping force control (skyhook control) at predetermined processing intervals (for example, 10 ms). When this skyhook control is executed, as shown in FIG. 8A, for example, when the right front wheel tries to get over the protrusion 102 of the road surface 100, the tire is caused by the pressing force by the protrusion 102 of the road surface 100. 14 is depressed toward the center and deformed, and the stroke of the suspension is contracted to become a full bump or a state close to a full bump. When the tire 14 rides on the protrusion 102 of the road surface 100, the wheel speed fluctuation increases to the plus side with reference to zero (see portion A in FIG. 7A).

  As shown in FIG. 8B, when the tire 14 is fully rebounded after lightly contacting the road surface after the right front wheel has passed over the protrusion 102, the wheel speed fluctuation exceeds a reference zero and is predetermined. Decrease to a value or more (refer to the thick solid line that is part B in FIG. 7A). At this time, the minus side determination unit 64 determines that the value of the wheel speed fluctuation detected by the wheel speed sensor 26 has fluctuated by a predetermined value or more on the minus side with reference to zero. Based on the determination, the minus side determination unit 64 assumes that the ground load of the wheel 16 on the road surface 100 has decreased, and outputs a control signal to the damping force control unit 54. The damping force control unit 54 increases the damping force of the suspension compared to before the value of the wheel speed fluctuation exceeds a predetermined value (see the thick broken line in FIG. 7B). In the present embodiment, by increasing the damping force before reaching full rebound (stroke end), it is possible to reduce full rebound shock and full bump shock after full rebound. In addition, C part of Fig.7 (a) has shown that the grounding load increased by the full bump after full rebound.

  That is, in this embodiment, when the ground contact load of the wheel 16 is decreased, the damping force of the suspension is increased, so that the piston rod of the damper 22 is less likely to be pulled downward, and the suspension arm 18 is rebound stopper (not shown). A full rebound shock and shock noise can be suppressed. Further, in this embodiment, since the high damping force increased when the right front wheel gets over the protrusion 102 and landed on the road surface 100, the vehicle body 12 can be slowly lowered and lowered, Convergence on the spring after landing can be improved. Thereby, it is possible to obtain a suspension control device capable of improving riding comfort without using an expensive sensor such as a stroke sensor.

  On the other hand, in the conventional suspension control that does not include a stroke sensor, after the right front wheel gets over the protrusion 102, a shock G is generated by the weight of the wheel 16, and the suspension stroke is fully rebounded. . In full rebound, the suspension arm 18 contacts a full rebound stopper (not shown) to generate a full rebound shock G and a large contact sound. Further, in the conventional suspension control that does not include a stroke sensor, there is a problem that after full rebounding, when the wheel 16 is landed on the road surface 100, the sprung is raised and the swaying is increased, thereby causing hunting.

  In this embodiment, the sprung G is rapidly reduced by reducing the ground load of the wheel 16 by performing a control to increase the damping force when the wheel speed fluctuation becomes a predetermined value or more on the minus side with zero as a reference. It is possible to prevent the sprung G from rapidly increasing after the contact load is reduced (see the thick broken line in FIG. 7C). As a result, in the present embodiment, it is possible to suppress the sudden decrease and increase of the sprung G and to obtain a gentle sprung G characteristic (see the thick broken line in FIG. 7C). In FIGS. 7B and 7C, a thick solid line related to the thick broken line indicates conventional suspension control that does not include a stroke sensor.

  Thus, in the present embodiment, the full rebound shock G and the shock noise can be suppressed, and the convergence on the spring after having landed on the road surface 100 over the protrusion 102 can be improved.

Next, first to fourth control examples for controlling the damping force will be described.
FIGS. 9A and 9B are characteristic diagrams showing a first control example of damping force, FIGS. 10A and 10B are characteristic diagrams showing a second control example of damping force, and FIG. FIGS. 12A and 12B are characteristic diagrams showing a third example of damping force control, and FIGS. 12A and 12B are characteristic diagrams showing a fourth example of damping force control.
9 to 12, each (a) is a characteristic diagram showing a correlation between time (t) on the horizontal axis and wheel speed fluctuation (km / h) on the vertical axis, and each (b) is a horizontal line. It is a characteristic view which shows correlation with time (t) of an axis | shaft, and the damping force of an ordinate.

In the first control example, the threshold (predetermined value) S is set to “−0.8”, and the control gain G is set to “1.0”.
As shown in FIG. 9 (a), in the first control example, when the wheel speed fluctuation exceeds zero and is equal to or greater than -0.8, which is the threshold value S, the minus-side determination unit 64 determines the damping force control unit. A control signal is output to the 54 peak hold unit 56. The peak hold unit 56 increases the damping force from 0.4 to 1.0, and holds the damping force peak in a state of 1.0.
In the first control example, the characteristic curve of the wheel speed fluctuation with respect to time exceeds the threshold value S and reaches the bottom B which is the lowest limit value, and the damping force is peak-held. There are features.

That is, the wheel speed fluctuation difference (ΔV) between the wheel speed fluctuation threshold value S and the bottom B value exceeding the threshold value S is obtained, and when this ΔV is relatively large, peak hold is performed. The damping force value is set to a large value, and when ΔV is relatively small, the peak holding damping force value is set to a small value. FIG. 9B illustrates a state where the damping force is peak-held at “1”.
Thereby, in the 1st control example, the suppression effect of the stable full rebound shock and the damping effect on the spring at the time of landing can be acquired.

In the second control example, the threshold value (predetermined value) S is set to “−0.6”. The control gain G is set corresponding to a difference (ΔV) in wheel speed fluctuation between the wheel speed fluctuation threshold value S and the bottom B value exceeding the threshold value S.
In the second control example, the case where the control gain G is set to “1.0” is exemplified, but the difference (ΔV) in the wheel speed fluctuation between the threshold S value and the bottom B value is illustrated. If it is relatively large, for example, the control gain G may be increased to “1.2” or “1.5”.
As shown in FIG. 10 (a), in the second control example, when the wheel speed fluctuation exceeds zero and is equal to or greater than -0.6, which is the threshold value S, the minus-side determination unit 64 determines the damping force control unit. The control signal is output to the 54 peak hold time adjustment unit 58. As shown in FIG. 10B, the peak hold time adjusting unit 58 increases the damping force from 0.4 to 1.0, and at the time when the peak of the damping force is 1.0, the time t1 is changed to the time t2. Is held for a predetermined time T. The peak hold time adjusting unit 58 appropriately sets the predetermined time T corresponding to the difference (ΔV) in the wheel speed fluctuation between the wheel speed fluctuation threshold value S and the bottom B value exceeding the threshold value S. The length can be adjusted.
For example, when the difference (ΔV) in wheel speed fluctuation between the threshold value S and the bottom B is relatively large, the peak hold time adjustment unit 58 determines the predetermined time from time t1 to time t3 (see the thick broken line). Peak hold is performed at T ′ (T <T ′).
As a result, in the second control example, when the ground contact load of the wheel 16 changes greatly (when the value of the wheel speed fluctuation is large), the behavior of the sprung (vehicle body 12) increases, so the peak hold time T By appropriately setting (T ′) and / or the control gain G, the vibration damping effect of the sprung (vehicle body 12) can be increased.

In the third control example, the threshold value (predetermined value) S is set to “−0.6”. The control gain G is set corresponding to a difference (ΔV) in wheel speed fluctuation between the wheel speed fluctuation threshold value S and the bottom B value exceeding the threshold value S.
In the third control example, the case where the control gain G is set to “1.5” is exemplified, but the difference (ΔV) in the wheel speed fluctuation between the threshold value S and the bottom B value is relatively small. If the control gain G is small, the control gain G is lowered to “1.2” or the difference in wheel speed fluctuation (ΔV between the threshold value S and the bottom B value)
) Is relatively large, it may be increased to “1.8”.
As shown in FIG. 11 (a), in the third control example, when the wheel speed fluctuation exceeds zero and is equal to or greater than -0.6, which is the threshold value S, the minus side determination unit 64 determines the damping force control unit. A control signal is output to the control gain adjustment 60 of 54. As shown in FIG. 11B, the control gain adjustment unit 60 increases the damping force from 0.4 to 1.5, and holds the damping force peak at 1.5. The control gain adjustment unit 60 can appropriately adjust the control gain G in accordance with the reduction amount (ΔV) of the ground load.
Thereby, in the third control example, when the ground contact load of the wheel 16 changes greatly (when the value of the wheel speed fluctuation is large), the behavior of the sprung (vehicle body 12) becomes large. By appropriately setting, the vibration damping effect of the sprung (vehicle body 12) can be increased.

In the fourth control example, the threshold value (predetermined value) S is constant at “−0.6”. For example, the control gain G at the first mountain is “1.0”, and the control gain G at the second mountain is “1”. .5 ", respectively.
In the fourth control example, when the threshold value S that is a predetermined value is continuously exceeded a plurality of times, the control gain G after the second time (second mountain) is increased with respect to the first time (first mountain). There is.
In the fourth control example, when the wheel speed fluctuation exceeds zero and becomes the threshold value S of −0.6 or more is the second time, the minus side determination unit 64 causes the threshold value adjustment unit 62 of the damping force control unit 54. Alternatively, a control signal is output to the control gain adjustment 60. The control gain adjustment unit 60 increases the damping force from 1.0 to 1.5 at the first time and holds the damping force peak at 1.5.
The threshold adjustment unit 62 may adjust the value of the second threshold S with respect to the value of the first threshold S. FIG. 12B illustrates a case where the control gain G at the second peak is increased with respect to the control gain G at the first peak.

When the threshold value S, which is a predetermined value, is continuously exceeded a plurality of times, it can be predicted that the control effect of the full rebound shock is insufficient in the first (first crest) damping force control. (Yamame) In order to speed up the subsequent control intervention, the control gain G may be increased or the threshold value S may be adjusted. Thereby, in the 4th example of control, effective suppression of a full rebound shock and the sprung mass damping effect at the time of landing can be acquired.
The control examples of the damping force are not limited to the first to fourth control examples. For example, the first to fourth control examples may be used in appropriate combination.

10 Automobile (vehicle)
16 wheels 22 damping force variable damper 26 wheel speed sensor 34 damper control means 36 state quantity calculation section 38 single wheel model calculation section (state quantity calculation means)
42 Gain circuit (basic input amount calculation means)
54 Damping force control unit 56 Peak hold unit 58 Peak hold time adjustment unit 60 Control gain adjustment unit 62 Threshold adjustment unit 64 Negative side determination unit

Claims (2)

A suspension control device for a vehicle having a damping force variable damper capable of adjusting a damping force in response to an input signal,
A wheel speed sensor for detecting the wheel speed of each wheel;
Basic input amount calculation means for calculating a basic input amount of the vehicle based on wheel speed fluctuation detected by the wheel speed sensor;
State quantity calculation means for calculating the state quantity of the vehicle by inputting the basic input quantity into a vehicle model representing the behavior of the vehicle;
Damper control means for controlling the damping force of the damping force variable damper based on the calculated state quantity;
With
When the wheel speed fluctuation value detected by the wheel speed sensor becomes equal to or greater than a predetermined value on the minus side with reference to zero, the damper control means compares the value before the wheel speed fluctuation value exceeds the predetermined value. Control to increase the damping force,
The suspension control means controls the damping force of the damping force variable damper provided in each of the left and right front wheels based on the state quantity having a larger wheel speed variation in the left and right front wheels. apparatus. The suspension control device according to claim 1, wherein the damper control unit increases a damping force before reaching full rebound.

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