JP3087508B2 - Vehicle running state detection device - Google Patents

Abstract

PURPOSE:To precisely detect that a tire is in a state of a nonlinear region in an apparatus which detects a vehicle running state on the basis of a yaw rate. CONSTITUTION:When both the absolute value of the difference between a target yaw rate and an actual yaw rate and the absolute value of the difference between an estimated yaw rate and the actual yaw rate are small, it is judged that a tire is situated in a linear region and that a road-surface gripping state is good [region (X)]. When both the absolute value of the difference between the target yaw rate and the actual yaw rate and the absolute value of the difference between the estimated yaw rate and the actual yaw rate are large, it is judged that n external disturbance is large [region (Y)].When the absolute value of the difference between the target yaw rate and the actual yaw rate is large and when the absolute value of the difference between the estimated yaw rate and the actual yaw rate is small, it is judged that the tire is in a state existing in a nonlinear region [region (Z)]. In this manner, a vehicle- running-state detection apparatus precisely detects that a vehicle is running in a state that the tire eists in the nonlinear region.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vehicle running state detecting device for detecting a running state of a vehicle based on a lateral momentum.

[0002]

2. Description of the Related Art There is known a vehicle traveling state detecting device for detecting a traveling state of a vehicle based on a lateral momentum. The vehicle traveling state detecting device includes (1) an actual lateral momentum detecting means for detecting an actual lateral momentum of the vehicle, and (2) a target momentum calculating means for calculating a target lateral momentum of the vehicle based on a steering angle of a steering wheel. (A) when the absolute value of the difference between the actual lateral momentum detected by the actual lateral momentum detecting means and the target lateral momentum calculated by the target lateral momentum calculating means is large, it is detected that the road surface grip state of the tire is poor. Vehicle running state detecting means. According to this device, it is possible to detect that the road surface grip condition of the tire is deteriorated due to the presence of disturbance such as road surface roughness and the cornering characteristic of the tire being in a non-linear region.

[0003] When a side slip occurs on a tire, a cornering force is generated. This cornering force increases with an increase in the side slip angle, but increases linearly with an increase in the side slip angle while the side slip angle is relatively small. This state is a state where the cornering characteristic of the tire is in the linear region, and hereinafter, the tire is abbreviated as being in the linear region. When the side slip angle increases, the cornering force does not increase linearly with the increase in the side slip angle, and the increasing tendency decreases. This state is a state in which the cornering characteristics of the tire are in the non-linear region, and hereinafter, the tire is abbreviated as being in the non-linear region. In the former case, the road grip state of the tire is good, but in the latter case, the road grip state of the tire is poor.

[0004] Japanese Patent Application Laid-Open No. 4-328029 discloses a vehicle traveling state detecting device for detecting that a road surface grip state of a tire is poor due to disturbance. The apparatus includes (1) an actual lateral momentum detecting means, (3) a lateral momentum estimating means for estimating a lateral momentum of a vehicle based on a rotational speed difference between left and right non-driving wheels, and (b) an actual lateral momentum detecting means. Vehicle running state detecting means for detecting that disturbance has occurred when the absolute value of the difference between the actual lateral momentum detected by the above and the estimated lateral momentum estimated by the lateral momentum estimating means is large. .

[0005]

However, there is a problem that the conventional two vehicle running state detecting devices cannot detect that the road surface grip state of the tire is poor due to the tire being in a non-linear region. Was. In the first vehicle running state detecting device, the fact that the tire has a poor road surface grip state includes a case where a disturbance is caused and a case where the tire is in a non-linear region. That is, when the tire is in the linear region, the road surface grip state of the tire is deteriorated due to the influence of disturbance, or when the tire is in the nonlinear region, the road surface grip state of the tire is deteriorated. Are detected without being distinguished.

On the other hand, the second vehicle running state detecting device detects that the tire has a poor grip on the road due to disturbance when the absolute value of the difference between the estimated lateral momentum and the actual lateral momentum is large. . However, when the absolute values of these differences are small, the road surface grip condition of the tire is good (the tire is in the linear region) and the road surface grip condition is due to a cause other than disturbance (caused by the tire being in the non-linear region). It includes both bad and bad cases. That is, it is not possible to distinguish whether the tire is in the linear region or the non-linear region.

In view of the above circumstances, it is an object of the present invention to provide a vehicle running state detecting device capable of accurately detecting that a tire has a poor road grip due to the tire being in a non-linear region. It was done.

[0008]

SUMMARY OF THE INVENTION The gist of the present invention is to provide a vehicle traveling state detecting device comprising: (1) an actual lateral momentum detecting means 1; Means 2, (3) lateral momentum estimating means 3, and (c) the absolute value of the difference between the detected value detected by the actual momentum detecting means and the estimated value estimated by the lateral momentum estimating means is small, and When the absolute value of the difference between the detected value detected by the actual momentum detecting means and the target value calculated by the target momentum calculating means is large , cornering of the tire
The cornering force increases as the skid angle increases.
Vehicle running state detecting means 4 which is in a non-linear region where the source does not increase linearly .

[0009]

When the road surface grip state of the tire is poor, the absolute value of the difference between the actual lateral momentum and the target lateral momentum increases.
When the road surface grip state of the tire becomes worse due to disturbance, the absolute value of the difference between the actual lateral momentum and the estimated lateral momentum increases, but the road grip state becomes larger due to the tire being in the nonlinear region. Is worse, the absolute value of the difference between the actual lateral momentum and the estimated lateral momentum does not increase.
Therefore, when the absolute value of the difference between the actual lateral momentum and the target lateral momentum is large and the absolute value of the difference between the actual lateral momentum and the estimated lateral momentum is small, the tire is in the non-linear region because the tire is in the nonlinear region. It is detected that the road surface grip state is poor.

The validity of the detection results has been confirmed by experiments. In FIG. 8, when a single (S) lane change is performed on a snow-covered road, that is, when the road surface grip state of the tire is good, the target lateral momentum (target yaw rate) and the actual lateral momentum (actual yaw rate) are compared. Both the absolute value of the difference and the absolute value of the difference between the estimated lateral momentum (estimated yaw rate) and the actual lateral momentum are small. When the S lane change is performed, it is estimated that the tire is in the linear region because the side slip angle is small. Actual lateral motion occurs according to the steering angle of the steering wheel, and a wheel speed difference occurs between the left and right non-driven wheels according to the actual lateral momentum.

When the S lane change is performed on a rutted road, that is, when the road surface grip state of the tire is poor due to disturbance such as road surface roughness, the absolute value of the difference between the target lateral momentum and the actual lateral momentum is also estimated. The absolute value of the difference between the momentum and the actual lateral momentum also increases.

When a sport run is performed on a low μ road, that is, when the side slip angle is large and the tire is in a non-linear region and the road surface grip state of the tire is poor, the target lateral momentum and the actual lateral momentum are calculated. Is large, and the absolute value of the difference between the estimated lateral momentum and the actual lateral momentum is small.

[0013]

According to the vehicle running state detecting device of the present invention, it is possible to accurately detect that the vehicle is running with the tires in the non-linear region. In addition, if the vehicle running state detecting device of the present invention is applied to a vehicle control device, it is possible to perform control to improve steering stability when a tire is detected to be in a non-linear region.

[0014]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram showing an embodiment of the present invention applied to a vehicle control device for a rear-wheel drive vehicle. In FIG. 2, reference numerals 10 and 12 denote left and right front wheels, and reference numerals 14 and 16 denote left and right rear wheels. The left and right front wheels 10 and 12 are connected by a steering mechanism 20 via a knuckle arm 18 and a tie rod 19. The output shafts of the engine are connected to wheel shafts (not shown) of the left and right rear wheels 14, 16 via a differential device. The vehicle in this embodiment is a rear-wheel drive vehicle.

The steering mechanism 20 is a rack and pinion type steering mechanism including a steering wheel 24, a steering shaft 25, a steering gear (not shown) and the like. The tie rod 19 is connected to a rack bar (not shown) and can be moved with the movement of the rack bar. The rack bar is engaged with a pinion (not shown) provided at the tip of the steering shaft 25 to constitute a steering gear.
The front wheels 10 and 12 are steered by being moved right and left with the rotation of the steering wheel 24.

When the steering wheel 24 is in a neutral position (steering angle is 0) and the vehicle is traveling straight, the rotation surfaces (steering direction) of the front wheels 10 and 12 and the front wheel 1
The traveling directions of 0 and 12 coincide. When the steering wheel 24 is steered and the front wheels 10, 12 are steered, they do not coincide and have a certain angle.
The angle between the steered direction and the traveling direction of the front wheels 10 and 12 is referred to as a side slip angle, and traveling in a state where the steered direction and the traveling direction of the front wheels 10 and 12 are different is referred to as traveling with a side slip.

If the vehicle travels with a skid, a cornering force is generated at right angles to the traveling direction of the wheels.
The cornering force increases with an increase in the side slip angle. However, when the side slip angle is relatively small, the cornering force increases linearly with an increase in the side slip angle. In this state, the road surface grip state of the tire is good. When the sideslip angle increases, the cornering force does not increase linearly with the increase in the sideslip angle, and the increasing gradient decreases. In this state, the tire has a poor grip on the road surface.

Left and right front wheels 10, 12, right and left rear wheels 14, 16
Supports a vehicle body (not shown) via a suspension device. The suspension device includes a spring (not shown), shock absorbers 28 to 31, actuator 3
4 to 37, etc., to improve the riding comfort by absorbing the impact of each of the wheels 10 to 16 from the road surface, and improve the steering stability by improving the road surface grip state of the wheels. is there. In this embodiment, as will be described later, the control of the vibration damping force of the suspension device is performed based on the running state of the vehicle.

The suspension device improves ride comfort and steering stability, but cannot improve both at the same time. That is, if the ride comfort is made soft, the steering stability is reduced, and if the ride stability is improved, the ride comfort becomes hard. When the vibration damping force of the suspension device is large, the riding comfort becomes hard. However, since the roll rigidity is increased, the vehicle body is hard to roll. Therefore, a large cornering force can be obtained for the same side slip angle. The road surface grip condition of the tire becomes good, and the steering stability becomes good. In other words, the driving is performed with more emphasis on the driving stability than the riding comfort, and the driving is more sporty. Conversely, when the damping force is small, the riding comfort is soft, but on the other hand, the vehicle is easily rolled, so that the vehicle posture becomes unstable and the steering stability is reduced. In other words, the driving is performed with emphasis on riding comfort rather than steering stability.

Next, the shock absorber 28 will be described. The other shock absorbers 29 to 31 are the same as the shock absorber 28 and will not be described. The shock absorber 28 that attenuates the vibration of the spring
3, a cylinder 40 filled with hydraulic fluid and a piston 44 provided with a valve 42 are provided. The inside of the cylinder 40 is divided into an upper chamber 48 and a lower chamber 50 by the piston 44.

The valve 42 has a valve body 52 and a hollow rotary valve 54, and controls the flow area of the working fluid by the rotation of the rotary valve 54.
As shown in the figure, the valve body 52 has positions A, B, C
Orifices 56, 57, 58 are formed, orifices 60 are formed at positions A corresponding to the orifices 56 on the outer periphery of the rotary valve 54, and orifices 61, 62 are formed at positions B corresponding to the orifices 57. An orifice 63 is formed in C. Rotary valve 5
A control rod 64 is fitted into 4, and the rotary valve 54 and the control rod 64 can be integrally rotated. An actuator 34 is attached to the control rod 64, and the control rod 64 is rotated by driving the actuator 34. A suspension control device 65 shown in FIG. 2 is connected to the actuator 34.
The rotary valve 54 is rotated by a command from the suspension control device 65.

When the rotary valve 54 is at the original position in the drawing, all the orifices 56 to 58 are opened. That is, the orifice 56 communicates with the orifice 60, the orifice 57 communicates with the orifice 61, and the orifice 58 communicates with the orifice 63.
And are communicated. This position of the rotary valve 54 is called software S.

When the rotary valve 54 is rotated clockwise from the original position in the figure by 60 °, all the orifices 56 to 58 are closed. The position of the rotary valve 54 in this case is referred to as a hard H position. Further, when the rotary valve 54 is rotated clockwise by 60 °, the orifices 57 and 62 are brought into communication with each other, and the medium is positioned at the medium M.

The operation when the rotary valve 54 is at the soft S position will be described. When the spring contracts, the piston 44 is lowered, and the hydraulic fluid in the lower chamber 50 flows to the upper chamber 48. As shown by arrows, the working fluid flowing into the rotary valve 54 through the passage 66 passes through the orifices 60 and 56, passes through the orifices 61 and 57, and passes through the orifices 63 and 5 as indicated by arrows.
8. Flow through passages 68,69. Some hydraulic fluid flows directly to the upper chamber 48 via the passage 69. Further, the spring extends and the piston 44 is raised, and the hydraulic fluid in the upper chamber 48 flows into the lower chamber 50 as shown by the arrow. That is, the working fluid flowing into the rotary valve 54 through the orifices 56 and 60 and the orifices 57 and 61 respectively passes through the passage 66 or the orifices 63 and 5.
8. Flow through passage 68. There is also a hydraulic fluid flowing directly to the lower chamber 50 through the passage 70. In this way, the flow of the hydraulic fluid is restricted by the valve 42 and the piston 44
The movement of the spring is hindered, and the expansion and contraction of the spring is attenuated.

When the rotary valve 54 is in the soft S position, all of the orifices 56 to 58 are open, so that the flow area of the hydraulic fluid in the valve 42 is the largest. Therefore, the flow of the hydraulic fluid becomes the easiest, and the movement of the piston 44 becomes the easiest, so that the expansion and contraction of the spring is most allowed. That is, the damping force of the shock absorber 28 is minimized, the riding comfort is soft, and the steering stability is reduced.

Similarly, when the rotary valve 54 is at the hard H position, the flow passage area of the valve 42 becomes the smallest. Therefore, the working fluid is most difficult to flow, the movement of the piston 44 is suppressed, and the expansion and contraction of the spring is suppressed. In this case, the working fluid only flows through the passage 69 or 70. That is, the damping force of the shock absorber 28 is maximized, the riding comfort is hard, and the steering stability is improved. Rotary valve 54
Is in the medium M position, the flow path area of the valve 42 is intermediate between the hardware H and the software S, and the ride comfort and steering stability are intermediate between the hardware and the software.

As described above, the damping force of the shock absorber 28 is controlled by changing the flow area of the valve 42, so that the riding comfort and the driving stability are controlled. In the present embodiment, as described above, it is possible to switch between three stages of software S, medium M, and hardware H.

The suspension control device 65 includes a CPU,
The computer mainly includes a RAM, a ROM, an input unit, an output unit, a bus, and the like. The input unit includes wheel speed sensors 76 to which detect the rotational angular velocities of the wheels 10 to 16.
79, a vehicle speed sensor 80, a steering angle sensor 82 for detecting a steering angle of the steering wheel 24, and a yaw rate sensor 84 as actual lateral momentum detecting means are connected. Actuators 34 to 37 are connected to the output unit.
The ROM also stores a wheel speed calculation program for calculating the wheel speed of each wheel based on the output signals of the wheel speed sensors 76 to 79, a damping force control program shown in the flowchart of FIG. And the like are stored.

The yaw rate sensor 84 is of a gyro type utilizing Coriolis force. Although the description is omitted because it is well known, it detects the rotational angular velocity of the vehicle about a vertical axis.

In the vehicle control device configured as described above, the damping force is determined based on the running state of the vehicle, the actuators 34 to 37 are driven, and the rotary rod 64
Is rotated to the determined position. The rotation position of the rotary rod 64 is determined based on the table shown in the graph of FIG. 5, and the table of FIG. 5 is created based on the table of FIG. is there.

First, the running state of the vehicle will be described.
The running state of the vehicle is detected based on the absolute value of the difference between the estimated yaw rate γ ′ and the actual yaw rate γ and the absolute value of the difference between the target yaw rate γ * and the actual yaw rate γ.

The actual yaw rate γ is calculated by the yaw rate sensor 84
Is obtained by filtering the output signal.

A relationship expressed by the following equation exists between the target yaw rate γ * and the steering angle θ of the steering wheel 24. γ * (s) / θ (s) = K (V) / (1 + Ts) where T is a time constant, s is a Laplace operator, K (V) is a target yaw rate steady-state gain, and γ * (s), θ
(S) is a function in which the target yaw rate γ * and the steering angle θ are each subjected to Laplace transform. The target yaw rate steady-state gain K (V) is a function of the vehicle speed V, as shown in FIG. 7, and is a value that takes into account the steering gear ratio and the like.
If the tires have good grip on the road,
The vehicle travels in a state uniquely determined by the steering angle θ of the steering wheel 24 and the vehicle speed V, and a yaw rate corresponding to the steering angle θ and the vehicle speed V is generated. Therefore, the yaw rate γ * obtained by the above equation can be used as the target yaw rate.

The estimated yaw rate γ 'is a value obtained by the following equation from the difference in wheel speed between the left and right front wheels 10 and 12 as non-driven wheels. γ ′ = (V _FR −V _FL ) / t where t is the tread. If there is no influence of disturbance,
Since a wheel speed difference occurs between the left and right front wheels 10 and 12 according to the actual yaw rate, the actual vehicle yaw rate can be estimated from the wheel speed difference between the left and right front wheels 10 and 12 by the above equation.

When the road surface grip condition of the tire is good,
That is, when the tire is in the linear region, since the yaw rate is generated according to the steering angle of the steering wheel 24, the absolute value of the difference between the target yaw rate γ * and the actual yaw rate γ decreases. On the other hand, when the road surface grip state of the tire is poor, the absolute value of the difference between the actual yaw rate γ and the target yaw rate γ * increases. The road surface grip state of the tire is deteriorated when the tire is in the linear region when it is affected by disturbance and when it is due to a cause other than disturbance (the tire is in the nonlinear region).

In the former case, since the rotational speeds of the left and right front wheels 10, 12 are changed by disturbance, the left and right front wheels 1 and 12 are changed.
At 0 and 12, there will be no difference in rotational speed between the actual yaw rate. As a result, the absolute value of the difference between the actual yaw rate γ and the estimated yaw rate γ ′ increases. That is, in this case, the actual yaw rate γ and the target yaw rate γ
The absolute value of the difference between * and the actual yaw rate γ and the estimated yaw rate γ ′ also increase. On the other hand, in the latter case, the absolute value of the difference between the actual yaw rate γ and the target yaw rate γ * increases, but the absolute value of the difference between the actual yaw rate γ and the estimated yaw rate γ ′ does not increase.

As described above, in FIG. 8, when the S lane change is performed on the snowy road, that is, when the road surface grip state of the tire is good, the value obtained by subtracting the actual yaw rate γ from the target yaw rate γ * Absolute value of | γ * −
γ | also decreases the absolute value | γ′−γ | of the value obtained by subtracting the actual yaw rate γ from the estimated yaw rate γ ′. Therefore,
Absolute value when tires have good road grip condition |
It can be seen that points determined based on the respective values, with γ′−γ | on the horizontal axis and the absolute value | γ * −γ | on the vertical axis, belong to the area (X) in FIG.

When the S lane change is performed on the rutted road, that is, when the road surface grip state of the tire is poor due to disturbance, the absolute value of the value obtained by subtracting the actual yaw rate γ from the target yaw rate γ * | γ * −γ | also increases the absolute value | γ′−γ | of the value obtained by subtracting the actual yaw rate γ from the estimated yaw rate γ ′. It can be seen that the points determined based on these absolute values belong to the area (Y) in FIG.
In addition, even when the tire is in the non-linear region and is subject to disturbance, it naturally belongs to the region (Y).

When a sport run is performed, that is, when the road surface grip state of the tire is poor due to a cause other than disturbance (the tire is in a non-linear region), the actual yaw rate γ is subtracted from the target yaw rate γ *. The absolute value | γ * −γ | of the calculated yaw rate becomes large, but the absolute value | γ′−γ | of the value obtained by subtracting the actual yaw rate γ from the estimated yaw rate γ ′ does not increase. Therefore, it can be seen that points determined based on these absolute values belong to the area (Z) in FIG. Thus, the respective absolute values | γ * −γ |, | γ′-γ
Is known, the running state of the vehicle can be known from the table of FIG. The table of FIG. 5 is created based on this fact.

In FIG. 5, the horizontal axis represents the estimated yaw rate γ '.
Estimated yaw rate deviation amount G (γ ′) = │γ′−γ |
V, and the vertical axis is the target yaw rate deviation amount G (γ *) = | γ * −γ | · V obtained by multiplying the absolute value of the value obtained by subtracting the actual yaw rate γ from the target yaw rate γ * by the vehicle speed V. . Although H, M, and S indicate the position of the control rod 64, it can be considered that they indicate the magnitude of the damping force. Here, since the vehicle speed V is the same on the horizontal axis and the vertical axis, the table in FIG. 5 and the table in FIG.

In FIG. 5, the target yaw rate deviation G
As (γ *) increases, the shock absorber 28
Damping force is increased. Further, as the estimated yaw rate deviation G (γ ′) is smaller, the target yaw rate deviation G (γ)
*) Is smaller, the damping force is increased. That is, for the same target yaw rate deviation G (γ *),
The smaller the estimated yaw rate deviation G (γ ′), the greater the damping force. When the estimated yaw rate deviation G (γ ′) is small and the target yaw rate deviation G (γ *) is large, it is considered that the tire is in a non-linear region, and the road surface grip state of the tire is considered to be poor. It increases power and improves steering stability. In particular, for a driver who travels with a large side slip angle, that is, a driver who runs a sport, it is desirable to improve the riding comfort to improve the steering stability.

Conversely, the same target yaw rate deviation G (γ
*), The larger the estimated yaw rate deviation G (γ ′) is, the smaller the damping force is. The larger the estimated yaw rate deviation G (γ ′) is, the larger the estimated yaw rate deviation G (γ ′) is due to the disturbance. Since the grip state is considered to be bad, even if the damping force is increased with an increase in the target yaw rate deviation G (γ *), the ride comfort is poor as in the case where the estimated yaw rate deviation G (γ ′) is small. This is because it is not possible to improve steering stability.

The absolute value | γ * −γ | of the value obtained by subtracting the actual yaw rate γ from the target yaw rate γ *, or the absolute value of the value obtained by subtracting the actual yaw rate γ from the estimated yaw rate γ ′ |
When γ′−γ | is constant and the vehicle speed V changes,
As the vehicle speed V increases, the damping force increases. This is because the higher the vehicle speed V, the higher the steering stability is required.

The actual control in the vehicle control device of the present embodiment will be described with reference to the flowchart of FIG. In step 1 (hereinafter, abbreviated as S1; the same applies to other steps), each data is initialized. S2
, The vehicle speed V, the wheel speeds V _FL and V _{FR of the} left and right front wheels 10 and 12, the steering angle θ of the steering wheel 24, the output value γ of the filtered yaw rate sensor 84, and the like are read. In S3 and S4, the target yaw rate γ * and the estimated yaw rate γ ′ are obtained, and in S5, the target yaw rate deviation G (γ *) and the estimated yaw rate deviation G (γ ′) are calculated, respectively. In S6, the damping force is determined to be one of H, M, and S based on the table shown in the graph of FIG. In S7,
The actuators 34 to 37 are driven based on the result. When the damping force is set to H, the control rod 64 is rotated clockwise by 60 ° from the position shown in the figure, and is set to the hard H position. When the damping force is set to M, the rotation is performed by 120 °, and when the damping force is set to S, the position is kept as shown.

As described above, according to the vehicle running state detecting device of this embodiment, it is possible to accurately detect that the road surface grip state of the tire is poor due to the tire being in the non-linear region. Further, according to the vehicle control device of the present embodiment, when the vehicle is running in a state where the tires are in the non-linear region, the steering stability can be improved.

In the above embodiment, when the damping force is determined to be H, M, S, respectively, the actuators 34 to 37 are controlled in the same manner. May be performed. Further, the damping force may be switched in two stages, or may be switched continuously with respect to the target yaw rate deviation amount G (γ *) or the like.

In the above embodiment, the vehicle running state detecting device is applied to the suspension control device, but may be applied to a rear wheel steering device or the like. For example, when the tire is in the non-linear region, the rear wheels are steered in the same direction as the front wheels to increase the understeer tendency. Further, the detection result by the vehicle running state detecting device may be output as it is to warn the driver that the tire is in a non-linear state. In that case, it is possible for the driver to focus on safe driving such as reducing the vehicle speed.

Although not specifically exemplified, the present invention can be implemented in various modified and improved forms based on the knowledge of those skilled in the art without departing from the scope of the claims.

[Brief description of the drawings]

FIG. 1 is a block diagram conceptually showing the configuration of the present invention.

FIG. 2 is a conceptual diagram in a case where a vehicle running state detecting device according to one embodiment of the present invention is provided in a rear wheel drive vehicle equipped with a vehicle control device.

FIG. 3 is a partial cross-sectional view of a shock absorber of the vehicle control device.

FIG. 4 is a flowchart illustrating a damping force control routine stored in a ROM of the vehicle control device.

FIG. 5 is a diagram showing a damping force determination table stored in a ROM of the vehicle control device.

FIG. 6 is a diagram illustrating a vehicle traveling state determination table used to create the table.

FIG. 7 is a diagram showing a relationship between a target yaw rate steady-state gain stored in a ROM of the vehicle control device and a vehicle speed.

FIG. 8 shows a target yaw rate γ * in each running state of the vehicle.
FIG. 9 is a diagram showing the results of an experiment in which the relationship between the actual yaw rate γ and the estimated yaw rate γ ′ and the actual yaw rate γ were examined.

[Explanation of symbols]

 Reference Signs List 10 left front wheel 12 right front wheel 24 steering wheel 65 suspension control device 76, 77 wheel speed sensor 84 yaw rate sensor

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int. Cl. ⁷ , DB name) B62D 6/00

Claims (1)

(57) [Claims] An actual lateral momentum detecting means for detecting an actual lateral momentum of the vehicle; a target momentum calculating means for calculating a target lateral momentum of the vehicle based on a steering angle of a steering wheel; Lateral momentum estimating means for estimating the lateral momentum of the vehicle based on the difference, and an absolute value of a difference between a detection value detected by the actual momentum detecting means and a target value obtained by the target momentum calculating means is large, and When the absolute value of the difference between the detected value detected by the actual momentum detecting means and the estimated value estimated by the lateral momentum estimating means is small ,
The cornering characteristics increase as the sideslip angle increases.
The ring force is in a nonlinear region where it does not increase linearly
Vehicle running state detecting device is characterized in that a vehicle running state detecting means to the state.