JP3089945B2 - Vehicle state estimation device - Google Patents

Abstract

PURPOSE:To estimate with a simple constitution and high precision a slide angle which is an angle which the advancing direction of a vehicle and longitudinal direction of the vehicle body during the turning make, with regard to a vehicle status estimation device. CONSTITUTION:A longitudinal vehicle speed sensor 12 which detects a vehicle speed mu in the longitudinal direction of the vehicle is arranged on the longitudinal axis line of the vehicle 10. A longitudinal acceleration sensor 14 which detects an acceleration Gx in the longitudinal direction of the vehicle and a yaw rate sensor 16 which detects a yaw rate tau during the turning of the vehicle are arranged in the vicinity of center of gravity of the vehicle. A vehicle slide angle calculation unit 22 of an ECU(Electronic Control Unit) 20 obtains a longitudinal component Sx of a centripetal force S generated during the turning of the vehicle by substracting du/dt from an acceleration Gx. Since the longitudinal component Sx is a product of a width direction vehicle speed v and a yaw rate tau, v=(du/dt-Gx)/rho is obtained by reverse calculation, and a vehicle slide angle beta is obtained as beta=tan<-1>(v/mu).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vehicle state estimating apparatus, and more particularly, to a vehicle in which a vehicle is traveling, the slip angle, which is an angle between the front-rear direction of the vehicle body and the traveling direction of the vehicle, can be accurately detected with a simple configuration. The present invention relates to a vehicle state estimating device for estimating.

[0002]

2. Description of the Related Art Turning of a vehicle is achieved by rotating four wheels at appropriate wheel speeds according to the turning state. Therefore, when the vehicle is turning, the individual wheels usually show different wheel speeds, and it is necessary to compare them on the same scale for vehicle control. When it is necessary to calculate the speed, it is necessary to convert the wheel speed for each wheel based on the state of the vehicle during turning.

[0003] Such conversion processing has heretofore been widely used in, for example, an anti-lock brake system for preventing locking of wheels, a braking control device for optimizing steering characteristics during turning by controlling braking force of individual wheels, and the like. .

In this case, the conversion process is usually performed based on a detection result of the vehicle body slip angle β defined as an angle formed by the traveling direction with respect to the center axis of the vehicle body in the front-rear direction during vehicle turning. Therefore, in performing the vehicle control as described above, detecting the vehicle body slip angle β with high accuracy is an important factor in securing control accuracy.

As a method of detecting the vehicle body slip angle β, for example, as disclosed in Japanese Patent Application Laid-Open No. 62-83247, an acceleration generated in the vehicle width direction during vehicle turning, that is, a lateral acceleration Gy And a yaw rate γ, which is an angular velocity about the center axis of the vehicle body during turning, is detected, and a calculation is performed by applying the yaw rate γ to the vehicle speed u according to the following equation.

Β = ∫ (Gy / u−γ) dt (1)

[0007]

However, the above-mentioned conventional method requires an integral operation to calculate the slip angle β as shown in the above equation (1). Therefore, when an error occurs in the detection value of the lateral acceleration sensor that detects the lateral acceleration Gy and the detection value of the yaw rate sensor that detects the yaw rate γ, the errors are accumulated in the process of calculating the vehicle body slip angle β. .

That is, when the vehicle body slip angle β is calculated by the above-described conventional method, errors of the lateral acceleration sensor, the yaw rate sensor, and the vehicle speed sensor are cumulatively added to the calculation result. There has been a problem that various sensors are required to have extremely high detection accuracy, and it is practically difficult to perform highly accurate estimation.

SUMMARY OF THE INVENTION The present invention has been made in view of the above points, and has been described in connection with a vehicle slippage based on a vehicle speed during a vehicle turning, an acceleration generated near a vehicle center of gravity, and a yaw rate of the vehicle body, without performing an integral operation. It is an object to provide a vehicle state estimation device that calculates the angle β.

[0010]

FIG. 1 is a block diagram showing the principle of a vehicle state estimating apparatus which achieves the above object. That is, as shown in FIG. 1, the above-described object is to set one of the vehicle body longitudinal direction and the vehicle width direction as a predetermined direction, and a predetermined direction vehicle speed detecting means M1 for detecting a vehicle speed in the predetermined direction, A predetermined direction acceleration detecting means M2 for detecting the acceleration in the predetermined direction, a yaw rate detecting means M3 for detecting a yaw rate of the vehicle body, a detection result of the predetermined direction vehicle speed detecting means M1, a detection result of the predetermined direction acceleration detecting means M2, And a vehicle direction calculating means M4 for detecting a vehicle speed in the direction perpendicular to the predetermined direction in the vicinity of the vehicle center of gravity based on the detection result of the yaw rate detecting means M3.
And a vehicle state estimating device M5 for estimating a vehicle body slip angle based on a detection result of the predetermined direction vehicle speed detecting device M1 and a calculation result of the straight direction vehicle speed calculating device M4. Achieved.

Further, in the vehicle state estimating device having the above configuration, the predetermined direction acceleration detecting means and the yaw rate detecting means are separated by a predetermined distance on the axis in the predetermined direction to detect the acceleration in the predetermined direction. The vehicle state estimating device constituted by a pair of acceleration detecting means provided is effective in reducing the cost of the device.

[0012]

In the vehicle state estimating means according to the present invention, the predetermined direction vehicle speed detecting means M1 detects a vehicle speed component in the predetermined direction. Therefore, the differential value of the detected value represents the acceleration generated in the entire vehicle body in accordance with the vehicle speed change in the predetermined direction.

On the other hand, in the vicinity of the vehicle center of gravity at which the predetermined direction acceleration detecting means M2 detects the acceleration, in addition to the acceleration accompanying the vehicle speed change in the predetermined direction, the acceleration toward the turning center during vehicle turning, that is, the centripetal force is obtained. Occurs. Therefore, when the vehicle is turning, the predetermined direction acceleration detecting means M
2 detects a composite acceleration of a predetermined direction acceleration accompanying a change in vehicle speed in a predetermined direction and a predetermined direction component of a centripetal force accompanying a turn.

That is, the predetermined direction acceleration detecting means M2
When the differential value of the detection result of the predetermined direction vehicle speed detecting means M1 is subtracted from the detection value of the above, the resulting value becomes a value representing the magnitude of the predetermined direction component of the centripetal force accompanying the turn.

Incidentally, the predetermined directional component of the centripetal force is a value obtained as v ² / r from the velocity v in a direction perpendicular to the predetermined direction and the turning radius r of the vehicle body. On the other hand, the turning radius r
Has a relationship of v = rγ between the yaw rate γ equivalent to the turning angular velocity ω of the vehicle body and the speed v.

Accordingly, the value of the predetermined directional component of the centripetal force obtained as a result of the subtraction is calculated as γv using the yaw rate γ detected by the yaw rate detecting means M3 and the speed component v near the center of gravity of the vehicle perpendicular to the predetermined direction. A value that can be represented.

In other words, if the yaw rate γ and the subtraction value are obtained, the velocity component v in the direction perpendicular to the predetermined direction is obtained.
Can be calculated backwards, and the straight-direction vehicle speed calculating means M4, based on the above principle, based on the detection results of the predetermined direction vehicle speed detecting means M1, the predetermined direction acceleration detecting means M2, and the yaw rate detecting means M3, The vehicle speed in the direction perpendicular to the predetermined direction is calculated without going through the integration process.

The vehicle body slip angle estimating means M5 includes:
On the basis of the ratio between the magnitude of the vehicle speed in the predetermined direction detected by the predetermined direction detection means M1 and the magnitude of the vehicle speed in the direction perpendicular to the predetermined direction detected by the perpendicular vehicle speed calculation means M4,
An angle formed by the traveling direction of the vehicle body with respect to the front-back direction of the vehicle body, that is, the vehicle body slip angle β is estimated.

When an acceleration sensor for detecting the acceleration in the front-rear direction or the vehicle width direction is provided at a predetermined distance in the vehicle front-rear direction or the vehicle width direction, the difference between the two detected accelerations is different from the vehicle. The value corresponds to the resulting yaw rate and the distance between the two acceleration sensors.

Therefore, when the pair of acceleration sensors are arranged on the axis of the vehicle body in a predetermined direction and separated by a predetermined distance,
The yaw rate detecting means M3 can be realized by these two acceleration sensors.

Further, when the acceleration in a predetermined direction near the center of gravity of the vehicle is detected by the pair of acceleration sensors, the predetermined direction acceleration detecting means M2 is realized.
The predetermined direction acceleration detecting means 2 and the yaw rate detecting means M3 are realized without using a yaw rate sensor.

[0022]

FIG. 2 is a diagram for explaining the configuration of a vehicle state estimating apparatus according to an embodiment of the present invention.
FIG. 2 shows an arrangement diagram of various sensors constituting a main part of the vehicle state estimating apparatus, and FIG. 2 (B) shows a main part of the vehicle state estimating apparatus of the present embodiment and controls an estimation result of the apparatus. An electronic control unit (E
FIG. 2 shows a block diagram of the CU).

FIG. 2A shows the x-axis in the vehicle longitudinal direction and the Y-axis in the vehicle width direction, with the center of gravity of the vehicle 10 as the origin (0, 0).
It is the figure which set and represented the axis. Therefore, in the figure, the X axis corresponds to the longitudinal axis of the vehicle 10 and the Y axis corresponds to the vehicle width direction axis of the vehicle 10. Note that FIG.
0 is on the right side in the figure.
L and FR denote left and right front wheels, respectively, and RL and RR denote left and right rear wheels, respectively.

The front and rear vehicle speed sensor 12 shown in FIG. 1 corresponds to the predetermined direction vehicle speed detection means M1, and is disposed on the X axis which is on the longitudinal axis of the vehicle. The front / rear vehicle speed sensor 12 is constituted by, for example, a Doppler type ground vehicle speed sensor, and detects only the vehicle speed u in the vehicle front / rear direction while the vehicle is traveling.

In this embodiment, the predetermined direction is set in the front-rear direction of the vehicle 10, and the front-rear vehicle speed sensor 12 only needs to be configured to detect only the vehicle speed u in the vehicle front-rear direction. Therefore, the front and rear vehicle speed sensor 12 can be realized by a wheel speed sensor disposed on the rear wheels RL and RR that rotate at an angular speed substantially corresponding to the vehicle speed u even when turning, for example, in addition to the ground vehicle speed sensor.

In the vicinity of the center of gravity of the vehicle 10, a longitudinal acceleration sensor 14 for detecting acceleration in the longitudinal direction of the vehicle and a yaw rate sensor 16 for detecting the angular velocity around the center of gravity of the vehicle when turning, that is, the yaw rate of the vehicle 10, are provided. ing.

The longitudinal acceleration sensor 14 corresponds to the predetermined direction acceleration detecting means M2, and the longitudinal direction, which is the predetermined direction in this embodiment, is set as the detection direction. Therefore, if any acceleration occurs near the center of gravity while the vehicle 10 is traveling, the longitudinal acceleration sensor 14 detects the longitudinal component of the combined acceleration obtained by combining all the accelerations.

The yaw rate sensor 16 corresponds to the above-described yaw rate detecting means M3, and detects the yaw rate γ during turning of the vehicle.

The ECU 20 shown in FIG. 2B mainly includes a microcomputer (not shown), and includes a random access memory (RAM) and a read only memory (RO).
M), a central processing unit (CPU) and the like are connected by a common bus.

Here, the ECU 20 implements the three arithmetic devices shown in FIG. 1 according to the contents of the processing executed by the built-in CPU.

The vehicle body slip angle calculating device 22 is a main part of this embodiment for realizing the above-described vehicle speed calculating device M4 in the straight direction and the vehicle body slip angle estimating means M5.
Upon receiving the detection signals from the longitudinal acceleration sensor 14 and the yaw rate sensor 16, respectively, the following processing is executed to estimate the vehicle body slip angle β when the vehicle 10 turns.

The vehicle model calculating device 24 calculates the vehicle based on β estimated by the vehicle body slip angle calculating device 22, the vehicle speed V near the center of gravity of the vehicle, the front wheel steering angle θ detected by the steering angle sensor 18, and the like. The wheel speed of each of the wheels FL, FR, RL, RR when the model 10 is modeled in an ideal state is calculated.

The hydraulic pressure control device 26 controls the brake pressures P _FL and P _FL to be supplied to the wheel cylinders of the wheels FL, FR, RL and RR in order to realize the ideal state calculated by the vehicle model calculation device 24. _FR , P _RL , and P _RR are controlled.

In this case, in order to realize an appropriate vehicle state by the braking force control, it is necessary that the hydraulic pressure control device 26 appropriately calculates the vehicle model on which the brake pressure control is based. In order for the calculation of the vehicle model to be performed appropriately,
Needs to be estimated with high accuracy.

The vehicle state estimating apparatus according to the present embodiment is characterized in that a high estimation accuracy is ensured by estimating the vehicle body slip angle β without performing the integration process in the vehicle body slip angle calculating device 22. . Hereinafter, a specific method of estimation and the contents of processing executed inside the ECU 20 to realize the estimation will be described.

FIG. 3 shows the relationship between the acceleration vector G generated near the center of gravity of the vehicle 10 and the centripetal force vector S associated with the turning when the vehicle 10 is turning at the speed V.

As shown in the figure, when the vehicle 10 turns, the centripetal force vector S is generated from the center of gravity of the vehicle toward the turning center, that is, in a direction perpendicular to the vehicle speed vector V, and its magnitude is S = V ² / r can be expressed by the turning radius r and the vehicle speed V. Then, between the turning radius r and the yaw rate γ and the vehicle speed V, V = r · γ
, The above relationship can be expressed as S = γ · V.

At this time, as shown in FIG. 3, the vehicle speed vector V has an angle of β with respect to the X axis which is the longitudinal axis of the vehicle, and the X-direction component Vx of V is u and the Y-direction component Vy is v
, The X-direction component Sx and the Y-direction component Sy of the centripetal force vector S are Sx = −v · γ and Sy =
u · γ.

On the other hand, if the vehicle 10 is turning without any acceleration or deceleration, only the centripetal force S acts on the vehicle center of gravity. An acceleration vector K due to acceleration / deceleration is superimposed on the center of gravity in addition to the centripetal force vector S.

In this case, the X component Kx of K changes the X component of the vehicle speed V, ie, u, and the Y component Ky of K acts to change the Y component of the vehicle speed V, ie, v. Therefore, Kx is the differential value of u, d
As u / dt, Ky can be expressed as a differential value dv / dt of v.

For this reason, the X-direction component Gx and the Y-direction component Gy of the acceleration vector G generated at the vehicle center of gravity during the cornering can be expressed by the following equations, respectively.

Gx = du / dt−v · γ (2) Gy = dv / dt + u · γ (3) In this case, Gx in the above equation (2) is X generated in the center of gravity of the vehicle. Since it is the directional acceleration, it is the acceleration itself detected by the longitudinal acceleration sensor 14. Γ is a value detected by the yaw rate sensor 16, and u is a value detected by the front and rear vehicle speed sensor 12.

Accordingly, the ECU 20 can calculate v, which is a component in the vehicle width direction, of the vehicle speed V by substituting the detection values supplied from these sensors into the above equation (2).

V = (du / dt−Gx) / γ (4) If v is obtained as described above, the vehicle body slip angle β can be obtained as in the following equation.

Β = tan ⁻¹ (v / u) (5) As described above, the longitudinal acceleration Gx generated near the center of gravity of the vehicle 10, the longitudinal vehicle speed u of the vehicle body, and the yaw rate γ at the time of turning are detected. However, when the vehicle body slip angle β is estimated based on the value, there is no need to perform any integration processing in the estimation process, which is extremely effective in securing high estimation accuracy.

Therefore, in this embodiment, the vehicle body slip angle β is estimated by the above-described method.
The above-mentioned estimation is realized by the CPU incorporated in the CU 20 executing the vehicle body slip angle estimation routine shown in FIG.

That is, when the routine shown in FIG.
Gx is read from. Next, at step 102, the yaw rate γ is read from the yaw rate sensor 16. Further, in step 104, the vehicle speed u in the front-rear direction is read from the front-rear vehicle speed sensor 12.

Then, in step 106, the read values are substituted into the above equation (4), and the result is further substituted in the above equation (5) in step 108, and the current processing is terminated.

In the present embodiment, the predetermined direction is set to the front-rear direction of the vehicle 10, and elements corresponding to the predetermined direction vehicle speed detecting means M1 and the predetermined direction acceleration M2 are determined by the front and rear vehicle speed sensor 12 and Although realized by the longitudinal acceleration sensor 14, the present invention is not limited to this, and the vehicle width direction may be set as the predetermined direction.

In this case, as shown in FIG. 5, a vehicle width / vehicle speed sensor 30 for detecting v which is a vehicle width direction component of the vehicle speed V is disposed on the Y axis corresponding to the axis in the vehicle width direction. A vehicle width acceleration sensor 3 for detecting a vehicle width direction acceleration Gy in the vicinity
2 and dispose them together with the yaw rate sensor 16 as an EC.
By connecting to U20, the hardware can be realized.

Further, by applying Gy, v, and γ detected from these to the relationship of the above equation (3),
U, which is a longitudinal component of the vehicle speed V, can be obtained. Thereafter, by substituting the obtained v and u into the above equation (5), integration processing is performed as in the case of the above-described embodiment. Without this, the vehicle body slip angle β can be estimated with high accuracy.

FIG. 6 is a diagram for explaining the overall configuration of a vehicle state estimating apparatus according to another embodiment of the present invention. FIG. 6A shows an arrangement diagram of each component, and FIG. FIG. 2 shows a block diagram of the ECU 40 constituting the main part. In FIG. 6, the same components as those in the embodiment shown in FIG. 2 are denoted by the same reference numerals, and description thereof will be omitted.

That is, the vehicle state estimating apparatus of this embodiment is provided with first and second acceleration sensors 42 and 44 instead of the yaw rate sensor 16 of the above embodiment,
It is characterized in that the vehicle body slip angle calculating device 46 configured inside 40 executes a new process described later correspondingly.

The first and second acceleration sensors 42,
Reference numeral 44 denotes the pair of acceleration sensors, and the distance L is symmetrical with respect to the X-axis which is the longitudinal axis of the vehicle set in a predetermined direction in the present embodiment with respect to the origin which is the vehicle weight center.
It is arranged to secure.

FIG. 7 shows the states of acceleration vectors G ₁ and G ₂ generated at any two points on the vehicle 10 turning at the vehicle speed V and the yaw rate γ. in this case,
The acceleration occurring at the point (c, a) on the XY coordinate is G ₁ , the X-direction component and the Y-direction component thereof are G _1x and G _1Y , respectively, and the acceleration occurring at the point (d, b) is G ₂ , the X
Assuming that the direction component and the Y direction component are G _2x and G _2Y , respectively, these can be expressed as follows using the front-rear direction vehicle speed u, the vehicle width direction vehicle speed v, and the yaw rate γ.

G _1x = du / dt−v · γ + a · dγ / dt−c · γ ² (6) G _2X = du / dt−v · γ−b · dγ / dt + d · γ ^2. (7) Therefore, the yaw rate γ and the longitudinal acceleration Gx at the vehicle center of gravity can be expressed by the following equations by modifying these equations.

Γ = ± {[{(a + b) · dγ / dt + (G _2X −G _1x )} / (c + d)] (8) Gx = du / dt−v · γ = ｛(G _1x + G _{2X) + (b-a)} · dγ / dt + (c-d) · γ 2} / 2 ··· (9) in this case, there in a straight line to the measurement point of the G _1, G ₂ passes through the vehicle body gravity center Assuming that a + b = 0 holds in the above equation (8), γ is expressed as follows for c + d = L.

Γ = ± {(G _2X −G _1x ) / L} (10) Further, the measurement points of G ₁ and G ₂ are on the X axis which is the longitudinal axis, and the vehicle weight is centered. In the case where they are arranged symmetrically with respect to the origin and the conditions of a = b = 0 and c = d are both satisfied, the above equation (9) can be simplified as the following equation.

Gx = (G _1x + G _2X ) / 2 (11) Therefore, according to the arrangement of the present embodiment shown in FIG. 6A, the detection values of the first acceleration sensor 42 are G _1x , By substituting the detection value of the second acceleration sensor 44 as G _{2X into} the above equations (10) and (11), the yaw rate γ and the longitudinal acceleration Gx can be easily and reliably detected.

In this case, by adding an inexpensive and simple-structure acceleration sensor as a sensor, an expensive and complicated-structure yaw rate sensor can be eliminated as a sensor, and there is no functional disadvantage. The whole system can be simplified and cost can be reduced.

FIG. 8 shows the yaw rate γ,
4 shows a flowchart of a routine executed by the vehicle body slip angle calculating device 46 to detect the longitudinal acceleration Gx.
This routine is a routine that is executed prior to the vehicle body slip angle estimation routine shown in FIG.

That is, when the routine shown in FIG. 8 is started, first in steps 200 and 202, the output value G _1x of the first acceleration sensor 42 and the second acceleration sensor 4
Read fourth detection values G _2x.

In step 204, G _1x and G _2x
Is substituted into the above equation (10), and in step 206,
G _1x and G _2x are substituted into the above equation (11), and the yaw rate γ and the longitudinal acceleration Gx are calculated, respectively, and the process ends.

Thereafter, the vehicle body slip angle calculating device 46 executes the above-described vehicle body slip angle estimation routine (FIG. 4) using the yaw rate γ and the longitudinal acceleration Gx calculated as described above to estimate the vehicle body slip angle β. I do.

In this embodiment, the predetermined direction is set to the vehicle longitudinal direction, and the yaw rate γ and the like are detected by detecting the longitudinal acceleration by the first and second acceleration sensors 42 and 44. However, the present invention is not limited to this, and the vehicle width direction may be set to the above-described predetermined direction.

In this case, as shown in FIG.
By arranging the acceleration sensors 42 and 44 on the Y-axis which is the axis in the vehicle width direction at a predetermined distance L and symmetrically with respect to the vehicle center of gravity, the yaw rate γ and the vehicle width direction acceleration G
y can be detected.

Therefore, with this configuration, a device for estimating the vehicle body slip angle β based on the vehicle width direction acceleration Gy, the vehicle width direction vehicle speed v, and the yaw rate γ as shown in FIG. 5 uses a yaw rate sensor. Therefore, the same effects as those of the embodiment shown in FIG. 6 can be substantially obtained.

The vehicle state estimating apparatus shown in FIGS. 6 and 9 respectively has the vehicle weight center on the X axis and the Y axis corresponding to the longitudinal axis of the vehicle 10 or the vehicle width direction. Although a pair of acceleration sensors 42 and 44 are arranged symmetrically, when one of the acceleration sensors is arranged near the center of gravity of the vehicle, desired calculations can be performed without symmetric arrangement.

That is, as described above, the yaw rate γ
Is simply calculated by using a + b = 0 in the above equation (8).
Is sufficient, and c = d does not need to be satisfied. Therefore, if one acceleration sensor is arranged at the origin which is the center of the vehicle weight and the other is arranged at an arbitrary point on the axis in a predetermined direction, this requirement is satisfied, while the value of the acceleration sensor arranged at the origin is directly calculated. If Gx or Gy is adopted, it is not necessary to simplify the above equation (9).

In this case, the longitudinal direction of the vehicle 10 and the width direction of the vehicle 10 can be selected as the axis in the predetermined direction, which is the arrangement condition of the acceleration sensor to be mounted other than near the vehicle center of gravity. Is the same as

Incidentally, in the vehicle state estimating apparatus of the present embodiment, the ECU 20, 40 includes the vehicle model calculating device 2.
4 and the hydraulic pressure control device 26, and performs the predetermined braking control process based on the estimated vehicle body slip angle β as described above. However, the application of the vehicle state estimating device is limited to only such control. It is not limited.

That is, the present invention can be applied to a control using the vehicle body slip angle β as a control parameter while the vehicle is running. For example, an antilock brake system which is a typical example of the above-described braking control, a steering characteristic during turning, In addition to a braking control device that corrects the vehicle speed, a known vehicle control such as a four-wheel drive or four-wheel steering system and an active suspension can be widely applied.

[0073]

As described above, according to the first aspect of the present invention, based on the vehicle speed in the predetermined direction, the acceleration in the predetermined direction near the vehicle center of gravity, and the yaw rate at the time of turning, the vehicle is perpendicular to the predetermined direction without going through the integration process. Speed components in various directions can be calculated, so that the vehicle body slip angle can be estimated without going through the integration process.

Therefore, according to the vehicle state estimating apparatus of the present invention, even if an error exists in the detected values of the vehicle speed, acceleration, yaw rate, etc., the error is accumulated in the calculation process of the vehicle body slip angle. In addition, the vehicle body slip angle can be estimated with high accuracy without unduly increasing the detection accuracy thereof.

According to the second aspect of the present invention, the yaw rate and the acceleration in a predetermined direction of the vehicle body can be detected using the pair of acceleration sensors, and the vehicle state estimating apparatus according to the first aspect is constituted. In this case, the yaw rate detecting means can be realized without using an expensive yaw rate sensor.

Therefore, according to the present invention, a vehicle state estimating apparatus capable of estimating a vehicle body slip angle with high accuracy can be realized with a simple configuration, that is, a configuration having high reliability, and at low cost. It has the feature of being able to.

[Brief description of the drawings]

FIG. 1 is a principle configuration diagram of a vehicle state estimating device according to the first aspect of the present invention.

FIG. 2 is a diagram for explaining an overall configuration of a vehicle state estimating apparatus according to an embodiment of the present invention.

FIG. 3 is a diagram illustrating a relationship between an acceleration vector generated near the center of gravity of the vehicle when the vehicle turns and a centripetal force vector generated due to the turn.

FIG. 4 is a flowchart of an example of a vehicle body slip angle estimation routine executed by the vehicle body state estimation device of the embodiment.

FIG. 5 is an overall configuration diagram of a vehicle state estimating apparatus according to another embodiment of the present invention.

FIG. 6 is a diagram for explaining an overall configuration of a vehicle state estimating apparatus according to another embodiment of the invention described in claim 2;

FIG. 7 is a diagram illustrating a state of acceleration generated at any two points on the vehicle during the turning travel.

FIG. 8 is a flowchart of an example of a conversion routine executed by the vehicle body state estimation device of the embodiment.

FIG. 9 is an overall configuration diagram of a vehicle state estimating apparatus according to another embodiment of the present invention.

[Explanation of symbols]

 M1 Predetermined direction vehicle speed detection means M2 Predetermined direction acceleration detection means M3 Yaw rate detection means M4 Direct vehicle speed calculation means M5 Body slip angle estimation means 10 Body 12 Front and rear vehicle speed sensor 14 Front and rear acceleration sensor 16 Yaw rate sensor 20, 40 Electronic control unit (ECU) 22, 46 Body slip angle calculating device 30 Vehicle width vehicle speed sensor 32 Vehicle width acceleration sensor 42 First acceleration sensor 44 Second acceleration sensor

Continuation of the front page (56) References JP-A-1-267462 (JP, A) JP-A-62-171866 (JP, A) JP-A-7-96848 (JP, A) JP-A-3-178878 (JP) , A) (58) Fields investigated (Int. Cl. ⁷ , DB name) G01P 15/00 B60T 8/58 B62D 6/00

Claims (2)

(57) [Claims] 1. A vehicle speed detecting means for detecting a vehicle speed in a predetermined direction with one of a vehicle body longitudinal direction and a vehicle width direction as a predetermined direction, and a predetermined direction detecting an acceleration in the predetermined direction near a vehicle center of gravity. Direction acceleration detecting means, yaw rate detecting means for detecting a yaw rate of the vehicle body, a vehicle body based on a detection result of the predetermined direction vehicle speed detecting means, a detection result of the predetermined direction acceleration detecting means, and a detection result of the yaw rate detecting means. Near the center of gravity, a vehicle speed calculating means for detecting a vehicle speed occurring in a direction perpendicular to the predetermined direction, a vehicle speed based on a detection result of the vehicle speed detecting means for the predetermined direction, and a calculation result of the vehicle speed calculating means for the perpendicular direction. A vehicle slip angle estimating means for estimating a slip angle of the vehicle. 2. The vehicle state estimating device according to claim 1, wherein the predetermined direction acceleration detecting means and the yaw rate detecting means are separated from the axis in the predetermined direction by a predetermined distance to detect the acceleration in the predetermined direction. A vehicle state estimating device comprising a pair of acceleration detecting means disposed as much as possible.