JPH0966852A - Anti-spin controller for setting method of controller - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent from getting into a spinning state without damaging the steering efficiency even under a severe running conditions by steering the steering wheel to turn the front wheels back and or applying brakes corresponding to the behavioral amount of a vehicle. SOLUTION: A target condition amount calculating means 4 calculates the target condition amount, which is to be the target for the vehicle gyrating movement, on the basis of the the vehicle steering wheel steering amount and the vehicle speed and a feedback amount calculating means 5 prevents the actual condition amount from diverging by the deviation of the actual condition amount of the vehicle gyrating movement detected by an actual condition amount detecting means 3 from the target condition amount together with the variations of the vehicle front wheel cornering stiffness and the rear wheel cornering stiffness on the basis of the vehicle speed. Thus the correction amount of the front wheel steering angle and the feedback amount, which is the braking power controlling amount of the respective wheels, are calculated and a control means 6 makes corrective steering of the front wheel steering angle and braking force control of the respective wheels on the basis of the feedback amount so that the vehicle may not get into a spinning condition.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an anti-spin control device, and more particularly to an anti-spin control device for preventing a vehicle from falling into a spin state.

[0002]

2. Description of the Related Art As a technique for preventing a sudden change in posture of a vehicle, more specifically, for the vehicle to fall into a spin state, there is an anti-spin technique described in JP-A-7-33039. This anti-spin technology focuses on the fact that the tire force characteristics of the rear wheels are saturated as the main cause of the vehicle falling into a spin state, and the front wheels for stabilizing the vehicle motion even when the tire force characteristics of the rear wheels are saturated. It provides a steering angle control law. As a result, even if the tire force characteristics of the rear wheels are saturated and the motion characteristics of the vehicle become unstable, the vehicle as a closed loop system including the control device is stabilized.

[0003]

However, the conventional anti-spin technology is assumed to run at a constant vehicle speed,
It is not considered that the cornering force of the front wheels increases due to the front-rear load movement during braking. Also,
Since a constant vehicle speed is assumed, active compensation for changes in vehicle speed, which is a parameter to be controlled, is not made,
Rapid changes in vehicle speed are not taken into consideration. Furthermore, in the prior art, a design is performed in which the saturation of the rear tire force characteristics is allowed, that is, the state where the inclination of the cornering force becomes zero is allowed, but on a real road surface, the inclination of the cornering force is more severe. It is also possible that

As described above, the prior art has room for improvement during acceleration / deceleration or when the cornering force has a negative inclination.

In view of the above facts, the present invention prevents the steering wheel from falling into the spin state without impairing the steering performance by the steering back steering and braking of the front wheels according to the behavior amount of the vehicle even under severe driving conditions. The aim is to obtain a control device that can do this.

[0006]

To achieve the above object, a vehicle anti-spin control device according to the present invention comprises a steering amount detecting means for detecting a steering amount of a steering wheel of the vehicle, and a vehicle speed detecting means for detecting a vehicle speed. An actual state quantity detecting means for detecting an actual state quantity which is a state quantity of the actual turning motion of the vehicle, and a target state quantity which is a target state quantity of the turning motion of the vehicle based on the vehicle speed and the steering amount. Based on the deviation between the target state quantity and the actual state quantity and the vehicle speed, the variation of the cornering stiffness of the front wheels and the variation of the cornering stiffness of the rear wheels of the vehicle To prevent the vehicle from falling into a spin state by preventing the actual state amount from diverging, the correction amount of the steering angle of the front wheels or the rear wheels and the braking force control amount of at least one wheel are reduced. Feedback amount calculation means for calculating a feedback amount which is one command value, and at least one control of a correction steering control of the steering angle of the front wheels or the rear wheels and a braking force control of at least one wheel based on the feedback amount. And a control means.

The controller setting method is the controller setting method of the feedback amount calculating means in the vehicle anti-spin control device according to claim 1, wherein the cornering stiffness of the front wheels and the rear wheels is within a predetermined variation range. In a control system including a process for simulating fluctuations in the vehicle, a vehicle motion model that simulates the motion of the vehicle, and the feedback amount calculation means, the fluctuations of the front wheels and the rear wheels that accompany the fluctuations of the slip angles of the front wheels and the rear wheels. A step of creating a closed loop considering as a change in the steering angle, a step of converting the closed loop into a system in which the closed loop is replaced, and a slip of the front wheel and the rear wheel due to a change in the steering angle of the front wheel and the rear wheel of the open loop. Configuring the controller such that the structured singular value of the angular variation is less than 1 in all frequency regions. And butterflies.

(Points of view of the present invention) It is considered that the main cause of the vehicle falling into the spin state is that the tire force characteristics of the rear wheels, that is, the rear wheel cornering force is saturated.
However, when the front wheel cornering force increases due to front-rear load movement such as during braking, fluctuations in the front wheel cornering force can also have an effect.
There is a problem in that even if the saturation characteristic of the rear cornering force is allowed, the increase in the front cornering force cannot be compensated. Further, the vehicle speed, which is a parameter to be controlled, constantly changes, and it is necessary to compensate for a sudden decrease in vehicle speed so as not to fall into a spin state. Furthermore, in a very severe situation where the rear wheel cornering force has a negative inclination on an actual road surface, it is possible to compensate for prevention of falling into a spin state under such severe conditions (hereinafter referred to as spin prevention). Is desired.
On the other hand, the inventors of the present invention have considered a spin prevention method that achieves spin prevention when the acceleration is reduced and the cornering force has a negative inclination. The method will be described below.

First, the inventors of the present invention have found that the increase in the front wheel cornering force due to the front-rear load movement, which may be one of the causes of the vehicle falling into the spin state, is equivalent to the front wheel cornering stiffness (gradient of the front wheel cornering force). We paid attention to the point equal to the fluctuation of. This can be expressed by the following equation.

Ff = cfp · αf cfp = cf (1 + Wf Δf) (−1 ≦ Δf ≦ 1)

However, Ff is the front wheel cornering force, cfp is the changed front wheel cornering stiffness,
αf is the front wheel slip angle, cf is the front wheel cornering stiffness nominal value used in the design, Δf is the standardized front wheel cornering stiffness variation, and Wf is the weight for standardizing the front wheel cornering stiffness variation, and cf (1 + Wf) represents the maximum value of the inclination of the front wheel cornering force, and cf (1-Wf) represents the minimum value of the inclination of the front wheel cornering force. In addition,
The front wheel cornering stiffness nominal value cf represents the average value of the maximum value and the minimum value of the inclination of the front wheel cornering force.

Further, the tire force characteristic variation of the rear wheels, which changes to a very severe situation where the inclination of the rear wheel cornering force becomes negative, is equivalent to the maximum value of the inclination of the rear wheel cornering force when the cornering stiffness of the rear wheel is equivalent. We focused on the point equivalent to changing from a (positive value) to a minimum value (negative value). This can be expressed by the following equation.

[0013] _{F r = crp · αr C rp} = cr (1 + Wr Δr) (-1 ≦ Δr ≦ 1)

However, Fr is the rear wheel cornering force, crp is the rear wheel cornering stiffness after fluctuation,
αr is the rear wheel slip angle, cr is the rear wheel cornering stiffness nominal value used in the design, Δr is the standardized variation of the rear wheel cornering stiffness, and Wr is the weight for the standardization of the rear wheel cornering stiffness variation. Where cr (1 + Wr) represents the maximum value of the inclination of the rear wheel cornering force, and cr (1-Wr) represents the minimum value of the inclination of the rear wheel cornering force. The rear wheel cornering stiffness nominal value cr represents the average value of the maximum value and the minimum value of the inclination of the rear wheel cornering force.

Next, the inventors of the present invention design the control system for preventing the spin from the fluctuation of the rear wheel cornering stiffness and the fluctuation of the front wheel cornering stiffness, which are the largest causes of the vehicle falling into the spin state. For both, we focused on the design of the controller that stabilizes the closed-loop system including the vehicle.

Further, the present inventors consider the change in the cornering stiffness of the front and rear wheels as the change in the front and rear wheel steering angles in the vehicle motion model equivalently having the vehicle speed as the parameter variable, and the change in the front and rear wheel steering angles. We considered that a stable control system design should be performed based on the robust control theory.

The present invention will now be described with reference to FIGS. As shown in FIG. 1, an anti-spin control device for a vehicle according to the present invention includes a steering amount detecting means 1 for detecting a steering amount of a steering wheel of the vehicle, a vehicle speed detecting means 2 for detecting a vehicle speed of the vehicle, and a vehicle speed detecting means 2. An actual state quantity detecting means 3 for detecting an actual state quantity as a state quantity of the turning motion, and a target state for calculating a target state quantity which is a target state amount of the turning motion of the vehicle based on the vehicle speed and the steering amount. Based on the vehicle speed and the deviation between the target state quantity and the actual state quantity and the vehicle speed, the actual state quantity is changed by the variation of the cornering stiffness of the front wheels and the variation of the cornering stiffness of the rear wheels of the vehicle. To prevent the vehicle from falling into a spin state by preventing divergence, a feedback amount as a command value of at least one of the correction amount of the steering angle of the front wheels and the braking force control amount of each wheel is set. A feedback amount calculation means 5 for calculation, a control unit 6 for performing at least one of the control of the corrective steering and braking force control of each wheel of the steering angle of the front wheel based on the feedback amount, and a.

The calculations in the target state quantity calculating means 4 and the feedback quantity calculating means 5 can be performed by the control system shown in FIG. 2, for example.

The control system shown in FIG. 2 has a block P0 (vx) corresponding to the target state quantity computing means 4, a block P (vx) which is a vehicle motion model not including fluctuations, blocks Δf and Δr representing fluctuations, and feedback. It comprises a controller C (vx) corresponding to the quantity calculation means 5. That is, the change in the cornering force of the front and rear wheels due to the change in the cornering stiffness of the front and rear wheels is equivalently regarded as the change in the front and rear wheel steering angle according to the slip angle of the front and rear wheels, and such a change in the front and rear wheel steering angle is included. As shown in FIG. 2, a control system including a vehicle motion model and a controller is described by separating the blocks Δf and Δr that represent fluctuations.

Here, the vehicle motion model P (vx) having the vehicle speed vx as a parameter, the front wheel steering angle and the fluctuation w (outputs of the blocks Δf, Δr) of the front and rear wheel steering angles equivalent to the actual vehicle, The slip amount z of the front and rear wheels standardized by multiplying the slip angles αp and αr of the front and rear wheels and the weights Wf and Wr by using the operation amount u that the control means 6 operates as an input, that is,

[0021]

[Equation 1] It is a mathematical model expressing the vehicle motion that outputs As a result of the standardization, the absolute values of the outputs of the blocks Δf and Δr are 1 or less.

In order to compensate the stability of the control system shown in FIG. 2 against fluctuations, the closed loop is opened before and after the blocks Δf and Δr representing the fluctuations, and the structured singular value of the open loop after the opening is set to less than 1. A control system design for This is a problem equivalent to the robust stabilization problem of the control system that does not include the steering amount of the steering wheel and the target state amount as shown in FIG.
Blocks Δf and Δ representing fluctuations in the control system shown in FIG.
The control system may be designed so that it is opened before and after r and the structured singular value of the open loop after the opening is less than 1.

By the way, although this vehicle motion model includes the vehicle speed as a parameter, if the controller is designed to be a vehicle speed dependent type, not only compensation at any vehicle speed but also spin prevention performance at a sudden vehicle speed change is performed. Will be compensated. The control system design that satisfies these conditions can be made by applying the gain scheduling type H ∞ control theory, for example.

By using the controller designed as described above as the feedback amount calculating means, it becomes possible to keep the vehicle stable with respect to changes in the cornering stiffness of the front and rear wheels, and the inclination of the cornering force during acceleration / deceleration can be maintained. The vehicle can run stably even under severe negative driving conditions and can prevent spin.

[0025]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

(First Embodiment) A first embodiment of the anti-spin control device of the present invention will be described with reference to FIGS. The first embodiment of the present invention detects lateral velocity and yaw angular velocity as actual state quantities, and achieves spin prevention by controlling braking force.

As shown in FIG. 4, the anti-spin control device of the first embodiment has a steering wheel steering amount detecting means 10 for detecting the steering amount of the steering wheel, a vehicle speed detecting means 20 for detecting the vehicle speed, and a vehicle speed detecting means 20. An actual state quantity detecting means 30 for detecting a lateral velocity and a yaw angular velocity which are actual state quantities of the turning motion as actual state quantities, and a lateral speed which is a desirable state quantity of the turning motion of the vehicle based on the vehicle speed and the steering amount of the steering wheel. And a target state quantity calculating means 40 for calculating a target state quantity corresponding to the yaw angular velocity, and a yaw to be added to the vehicle so as to prevent the vehicle from spinning based on the deviation between the target state quantity and the actual state quantity and the vehicle speed. It comprises a feedback amount calculation means 50 for calculating a moment and a control means 60 for controlling the braking force of each front wheel from the feedback amount.

The steering wheel steering amount detecting means 10 comprises a steering angle sensor 11 which is mounted coaxially with the steering wheel and outputs a voltage proportional to the steering angle of the steering wheel.
The steering angle of the steering wheel is detected, and a value corresponding to the front wheel actual steering angle obtained by dividing the detected steering angle by a value corresponding to the steering wheel gear ratio is output to the target state amount calculation means 40 as a steering amount signal δ.

The vehicle speed detecting means 20 is composed of a vehicle speed sensor 21 for detecting the forward and backward speeds of the vehicle. The vehicle speed is estimated from the rotational speeds of the four wheels, and a value corresponding to the calculated vehicle speed is calculated. The vehicle speed signal vx is output to the target state amount calculation means 40 and the feedback amount calculation means 50.

The actual state quantity detecting means 30 is the lateral velocity sensor 3
1 and a yaw angle sensor 32. In this embodiment, a non-contact speedometer is used as the lateral speed sensor 31, the lateral speed sensor 31 detects the lateral speed, converts the detected lateral speed into an electric signal, and converts the converted electric signal into the lateral speed. Output as signal vy. The lateral speed signal vy output from the lateral speed sensor 31 is combined with the target lateral speed vy0 output from the target state amount calculating means 40 in the combining means 42 and output to the feedback amount calculating means 50.
The lateral speed may be an estimated value calculated by using an observer or the like from the steering amount of the steering wheel, the vehicle speed, the yaw angular speed, the lateral acceleration, and the like. In this case, since it is not necessary to use a speedometer, the system becomes a practical system. Further, the yaw angular velocity sensor 32 is attached to the vehicle center of gravity position, detects the yaw angular velocity at the vehicle center of gravity position, and outputs a value corresponding to the detected yaw angular velocity as a yaw angular velocity signal γ. The yaw angular velocity signal γ output from the yaw angular velocity sensor 32 is combined with the target yaw angular velocity signal γ0 output from the target state amount calculating means 40 in the combining means 44 and output to the feedback amount calculating means 50.

Target state quantity calculating means 40, synthesizing means 42,
44 and the feedback amount calculation means 50 are constituted by a digital computer. The steering wheel operation amount δ, the vehicle speed vx, the lateral velocity vy as the actual state amount, and the yaw angular velocity γ are input to the digital computer, and the feedback amount u, which is the yaw moment generated by the distribution of the braking force of each wheel, is ( It is adapted to be output to the control means 60 (from the feedback amount calculation means 50).

The contents of the calculations in the target state quantity calculating means 40 to the feedback quantity calculating means 50, which are digital computers, will be described below.

First, a vehicle motion model in consideration of the variation in the cornering stiffness of the front and rear wheels will be described.
In the following description, the time derivative of the function x is x ′,
The transpose of the matrix A is represented as ^AT .

The vehicle motion having the lateral velocity vy and the yaw angular velocity γ as state quantities can be described by the following state equation.

X ′ = A (vx) · x + B1 · Δ · z + Bf · δ + B2 · u (1) z = C (vx) · x + Df · δ where A (vx) = [al a2] B1 = [B1 b2] B2 = [0 1 / Iz] ^T Bf = [cf / maf · cf / Iz] ^T C (vx) = [cl c2] Df = [Wf 0] ^T x = [vy γ] ^T

[0036]

[Equation 2] Further, a1 = [all a21] ^T a2 = [al2 a22] ^T a11 = − (cf + cr) / (m · vx) a21 = − (af · cf−ar · cr) / (Iz · vx) a12 = − ( af · cf-ar · cr) / (m · vx) a22 = -vx- (af 2 · cf-ar 2 · cr) / (I
z · vx) b1 = [cf / maf · cf / Iz] ^T b2 = [cr / m −ar · cr / Iz] ^T c1 = [Wf / vx Wr / vx] ^T c2 = [Wf · af / vx -Wr · ar / vx] ^T where af and ar are the distances between the axles of the front wheels and the rear wheels and the center of gravity Iz: the yaw moment of inertia m: the vehicle mass u: the yaw moment z: are the weighted front and rear wheel slip angles.

The target state quantity calculating means 40 calculates the steering quantity signal δ.
Based on the vehicle speed signal vx, the target lateral speed vy0 and the target yaw angular speed γ0, which are the vehicle motion state quantities that the driver can most easily operate, are output as the target state quantity signal x0. Here, a linear model represented by the following expression (2) on a high μ road is considered as the dynamic characteristic of such vehicle behavior.

X0 ′ = A0 (vx) × x + Bf0 · δ (2) where A0 (vx) = [a10 a20], Bf0 = [cf0 / m af · cf0 / Iz] ^T x0 = [vy0 γ0] ^T Further, a10 = [a110 a210] ^T a20 = [a120 a220] ^T a110 = − (cfo + cr0) / (m · vx) a210 = − (af · cf0−ar · cr0) / (Iz · v
x) a120 = - (af · cf0-ar · cr0) / (m · vx) a220 = -vx- (af 2 · cf0-ar 2 · cr0) / (Iz
Vx) where cf0 and cr0 are the cornering stiffness of the linear model.

The feedback amount calculation means 50 optimizes the behavior of the vehicle with respect to the steering amount of the steering wheel within a range where the vehicle does not fall into a spin on the basis of the deviation between the actual state quantity x and the target state quantity x0, and also the cross wind or the like. The yaw moment generated by the distribution of the braking force for making the actual state amount x follow the target state amount x0 so as to improve the stability against disturbance is calculated as the feedback amount u.

The calculation algorithm in the target state amount calculating means 40 and the feedback amount calculating means 50 can be designed by using the model of the control system shown in FIG. That is, in the present embodiment, as shown in FIG. 5, a block P0 (vx) corresponding to the target state quantity computing means 40 and a block P (v
x), blocks Δf and Δr representing fluctuations, and state feedback gain K corresponding to feedback amount calculating means 5
(Vx). That is, a change in the cornering force of the front and rear wheels due to a change in the cornering stiffness of the front and rear wheels is equivalently regarded as a change in the front and rear wheel steering angle according to the slip angle of the front and rear wheels, and the blocks Δf and Δr representing the change are separated. The system is assumed.

In the control system shown in FIG. 5, the above-mentioned arithmetic algorithm uses arbitrary fluctuations Δf, Δ whose absolute values are 1 or less.
The closed loop system including r is designed to be stable.

Here, the block P of the control system shown in FIG.
(Vx) represents the above equation (1), and inputs the steering wheel steering amount δ, the equivalent front / rear wheel steering angle change w (Δf, Δr), and the yaw moment u generated by the distribution of the braking force, and It is a mathematical model expressing the motion of the vehicle including, as parameters, the actual state amount x of the vehicle composed of the lateral velocity vy and the yaw angular velocity γ and the vehicle speed vx that outputs the weighted front and rear wheel slip angles z. Block P0 (vx)
Represents the above equation (2), which is a target of the vehicle including the vehicle speed vx with the steering wheel operation amount δ as an input and the target lateral velocity vy0 and the target yaw angular velocity γ0 that are the target state amount x0 of the vehicle as output parameters. It is a mathematical model expressing motion.

By the way, discussing the stability of the control system shown in FIG. 5 is equivalent to discussing the stability of the control system not including the steering amount δ of the steering wheel and the target state amount shown in FIG. Therefore, the controller is designed using the control system shown in FIG. In this case, it is assumed that the steering amount of the steering wheel is zero in FIG.

Here, in order to stabilize the closed loop system including the arbitrary fluctuations Δf and Δr whose absolute value is 1 or less in the control system shown in FIG. 6, the front and rear wheels standardized from the front and rear wheel steering angle change w. It is known as the small gain theorem that the control system may be configured so that the structured singular value up to the slip angle z is less than 1. Here, the vehicle speed v to be considered
v1 ≦ vx ≦ v2 is set as the region of x, and no matter how the vehicle speed vx changes within this region, the structuring from the front and rear wheel steering angle change w to the standardized front and rear wheel slip angle z is always performed. A control system is designed so that the singular value is less than 1.

First, if θ1 = v1 (v2-vx) / {vx (v2-v1)} θ2 = (vx-v1) / (v2-v1) θ3 = 1-θ1-θ2 is defined, A (vx) = Θ1 · A1 + θ2 · A2 + θ3 · A3 (3) C (vx) = θ1 · C1 + θ2 · C2 + θ3 · C3 (4) However, A1 = [a101 a201], C1 = [c101 c201] A2 = [2. a102 a202], C2 = [c102 c202] A3 = [a103 a203], C3 = [c103 c203] Further, a101 = [a1101 a2101] ^T , a201 = [a1201]
a2201] ^T a102 = [a1102 a2102] ^T , a202 = [a1202
a2202] ^T a103 = [a1103 a2103] ^T , a201 = [a1203
a2203] ^T a1101 = − (cf + cr) / (m · vl) a2101 = − (af · cf−ar · cr) / (Iz · v)
1) a1201 = - (af · cf-ar · cr) / (m · v1) a2201 = -v1- (af 2 · cf-ar 2 · cr) /
(Iz · v1) a1102 = − (cf + cr) / (m · v2) a2102 = − (af · cf−ar · cr) / (Iz · v)
2) a1202 = - (af · cf-ar · cr) / (m · v2) a2202 = -v2- (af 2 · cf-ar 2 · cr) /
(Iz · v2) a1103 = − (cf + cr) / (m · v2) a2103 = − (af · cf−ar · cr) / (Iz · v)
2) a1203 = - (af · cf-ar · cr) / (m · v2) a2203 = -v1- (af 2 · cf-ar 2 · cr) /
(Iz · v2) c101 = [Wf / v1 Wr / v1] ^T c201 = [Wf · af / v1 -Wr · ar / v1] ^T c102 = [Wf / v2 Wr / v2] ^T c202 = [Wf · af / v2-Wr · ar / v2] ^T c103 = [Wf / v2 Wr / v2] ^T c203 = [Wf · af / v2-Wr · ar / v2] ^{T It} can be expressed as an LPV (Linear Parameter Varying) system. The description of such a system makes it possible to apply the gain scheduling H∞ control theory, so that it is possible to design a controller adapted to the vehicle speed. Here, arbitrary θ1, θ2, θ3 (however, θ1
> 0, θ2> 0, θ3> 0, θ1 + θ2 + θ3 = 1) and the LMI is a state feedback control law expressed in the form of the following equation in which the constant scaling H∞ norm is less than 1.
(Linear Matrix Inequarity).

U = (θ1 · K1 + θ2 · K2 + θ3 · K3) · (x−x0) ·· (5)

When this control law is used, the vehicle speed is v1≤v
It is possible to stabilize the vehicle motion even when it arbitrarily changes within the region of x ≦ v2. By the way, θ
1, θ2, θ3 are functions of the vehicle speed vx, and the control law of the above equation (5) is configured to continuously change the gain according to the vehicle speed.

The control means 60 generates a yaw moment for preventing spin by applying a braking force to the front wheel on the outside of the turning on the basis of the feedback amount signal u.

Next, the operation of the first embodiment will be described. First, the outputs of the steering angle sensor 11, the vehicle speed sensor 21, the lateral speed sensor 31 and the yaw angular speed sensor 32 are the target state quantity calculating means 40 and the feedback quantity calculating means. It is input to the digital computer constituting 50.

In this digital computer, first,
In the target state quantity calculating means 40, the target lateral velocity vy0 and the target yaw angular velocity γ0, which are the state quantities of the target vehicle, are calculated according to the recurrence formula obtained by discretizing the formula (2).

The target state quantity is in accordance with the dynamic characteristics of the vehicle model when traveling at a constant vehicle speed on a high μ road having a margin of tire force characteristics. When there is no disturbance from the external environment such as side wind disturbance, the actual state quantity matches the target state quantity.

Next, in the feedback amount calculation means 50, the yaw moment required to bring the deviation between the target state quantity and the actual state quantity actually measured, which is caused by the fluctuation of the road surface condition, the load movement, the lateral wind disturbance, etc., toward zero. The feedback amount signal u which is the correction amount of is calculated according to the equation (5) based on the vehicle speed vx and the deviation between the actual state amount and the target state amount.
This feedback amount signal u makes it possible to make the dynamic characteristics of the vehicle state follow the target dynamic characteristics within a physically possible range even when there is a disturbance or the like. Here, the system stability is compensated even when the vehicle speed changes greatly and the cornering force inclination of the front and rear wheels changes due to load movement, and even in the area beyond the limit where the rear wheel cornering force inclination becomes negative. The feedback amount calculation means 50 is designed in the above.

Next, the control means 60 generates a yaw moment by applying a braking force to the front wheel on the outside of the turning on the basis of the feedback amount signal u which is a yaw moment for preventing spin.

In the present embodiment, the case where the braking force is applied to the front wheel on the outside of the turning to generate the yaw moment has been described, but the front wheel steering angle may be controlled, or the front wheel steering angle may be controlled. And the braking force may be applied to the front wheels.

From the above, the anti-spin control device of the present embodiment is capable of maneuvering performance even under severer driving conditions which cannot be compensated by the conventional technique, such as during acceleration / deceleration or when the rear wheel cornering force becomes negative. It is possible to prevent spin without impairing the spin rate.

(Second Embodiment) Next, a second embodiment of the anti-spin control device of the present invention will be described with reference to FIGS. 7 to 9. Since the second embodiment has the same configuration as that of the first embodiment, the same parts in FIGS. 7 to 9 are designated by the same reference numerals and detailed description thereof is omitted, and the following description focuses on the different points. To do.

In the antispin control device of the second embodiment, the braking force of each wheel is individually variable by control.
For the S-mounted vehicle, the yaw angular velocity is detected as the actual state quantity, and the braking force distribution control of each wheel is performed to prevent spin.

The yaw angular velocity γ as the actual state quantity is one element of the vehicle motion state x and can be expressed by the following equation (6).

Γ = C · x (6) However, C = [0 1] Further, the target yaw angular velocity γ0 as the target state quantity can be similarly expressed as follows.

Γ0 = C · x0 (7)

As shown in FIG. 7, the anti-spin control device of the present embodiment has a steering wheel steering amount detecting means 10 for detecting the steering amount of the steering wheel, a vehicle speed detecting means 20 for detecting the speed of the vehicle, and an actual vehicle. State quantity detecting means 30 for detecting the yaw angular velocity, which is the state quantity of the turning motion of the robot, as the actual state quantity
And a target state quantity calculating means 40 for calculating a target state quantity corresponding to a yaw angular velocity which is a desirable state quantity of the turning motion of the vehicle based on the vehicle speed and the steering amount of the steering wheel, and the target state quantity and the actual state quantity. Feedback amount calculation means 50 for calculating a yaw moment to be applied to the vehicle so as to prevent the vehicle from spinning based on the deviation of the vehicle speed and the vehicle speed.
A brake operation amount detecting means 60 for detecting a brake operation amount of a driver, an ABS operation status detecting means 70 for detecting an ABS operation status, the brake operation amount and the ABS.
A braking force distribution unit 80 that outputs a command value of the braking torque of each wheel based on the operating condition and the feedback amount, and a control unit 9 that controls the braking torque of each wheel according to the braking torque command value.
0.

The brake operation amount detecting means 60 comprises a brake stroke operation amount sensor 61. The brake stroke operation amount sensor 61 detects the brake stroke operation amount by the driver, and sets the target value of the four-wheel braking torque corresponding to the detected operation amount as a four-wheel braking torque target value signal to the basic distribution of the braking force distribution means 80. Output to the means 81.

The ABS operating status detecting means 70 detects the ABS operating status, detects how much the braking torque applied to each wheel by the ABS is reduced, and controls the corresponding braking torque as an ABS operating torque signal. It outputs to the ABS correction means 83 of the power distribution means 80.

In this embodiment, the vehicle speed detecting means 2
0 also outputs the vehicle speed signal vx to the basic distribution means 81.
Further, the actual state amount detecting means 30 is composed of a yaw angle sensor 32, and the yaw angular velocity signal γ is applied to the basic distribution means 8
Also output to 1.

Further, the braking force distribution means 80 of the present embodiment
Is a basic distribution means 81 for estimating the load distribution of each wheel and distributing the four-wheel braking torque target value signal to each wheel according to the load distribution.
A yaw moment correction means 82 for correcting the braking torque target value distributed to each wheel by the basic distribution means 81 according to a feedback amount which is a yaw moment, and a braking torque target value modified by the yaw moment correction means 82. Is corrected based on the ABS operation torque signal, and the ABS correction means 83 for outputting the braking torque command value for each wheel.

The basic distribution means 81 is for estimating the load distribution of each wheel from the vehicle speed and the yaw angular velocity as the actual state quantity, and distributing the four-wheel braking torque target value signal to each wheel according to the load distribution. is there. This basic distribution means 81 uses the vehicle speed signal v
x, the yaw angular velocity signal γ, and the four-wheel braking torque target value signal from the brake operation amount detecting means 60 are input, and the four-wheel braking torque target value signal according to the estimated load distribution of each wheel is used as a yaw moment. It outputs to the correction means 82.

The yaw moment correction means 82 corrects the braking torque target value of each wheel according to the feedback amount u,
This is for realizing the yaw moment of the feedback amount u. This yaw moment correction means 82 is a four-wheel braking torque target value signal from the basic distribution means 81 and a feedback amount u from the feedback amount calculation means 50.
And the corrected feedback amount A
Output to the BS correction means 83.

The ABS correction means 83 corrects the braking torque target value of each wheel based on the ABS operation torque signal of each wheel in order to correct the fluctuation of the yaw moment due to the ABS operation when the ABS operates, and the feedback amount u This is to compensate for the realization of the yaw moment of. This ABS correction means 83 is provided by the ABS operation status detection means 70.
The S operation torque signal and the output signal from the yaw moment correction means 82 are input, and the braking torque command value for each wheel is output to the control means 90.

The control means 90 is for braking each wheel on the basis of the braking torque command value for each wheel to achieve both the turning and braking characteristics intended by the driver and the prevention of spin.

Target state quantity computing means 40, synthesizing means 44,
Feedback amount calculation means 50 and braking force distribution means 8
0 is constituted by a digital computer. The steering wheel operation amount δ, the vehicle speed vx, the yaw angular velocity γ as the actual state amount, the four-wheel braking torque target value signal, and the ABS operation torque signal are input to this digital computer, and the braking torque command value for each wheel is input. , Control means 6
Output to 0.

The contents of the calculation in the target state amount calculating means 40 to the feedback amount calculating means 50 which are constituted by a digital computer will be described below.

The target state quantity calculating means 40 determines the steering quantity signal δ.
Based on the vehicle speed signal vx, the target yaw angular velocity γ0, which is the vehicle motion state quantity such that the driver can most easily steer, is calculated according to the equations (2) and (7).

The feedback amount calculating means 50 optimizes the behavior of the vehicle with respect to the steering amount of the steering wheel within a range where the vehicle does not fall into a spin based on the deviation between the yaw angular velocity γ and the target yaw angular velocity γ0, and also determines the side wind. The yaw moment generated by the distribution of the braking force for making the yaw angular velocity, which is the actual state amount, follow the target yaw angular velocity, which is the target state amount, is calculated as the feedback amount so as to improve the stability against disturbance.

The calculation algorithm in the target state amount calculation means 40 to the feedback amount calculation means 50 can be designed by using the control system shown in FIG. 8 as a model. That is, in the present embodiment, as shown in FIG. 8, the block P0yaw (vx) corresponding to the target state quantity computing means 40,
Block Pyaw that is a vehicle motion model that does not include fluctuations
(Vx), blocks Δf and Δr representing fluctuations, and output feedback C (v corresponding to the feedback amount calculation means 5
x).

In the control system shown in FIG. 8, the above-mentioned arithmetic algorithm uses arbitrary fluctuations Δf, Δ whose absolute values are 1 or less.
The closed loop system including r is designed to be stable. Here, Pyaw (vx) is equation (1) and (6)
The vehicle speed vx is represented by a formula, in which a yaw moment generated by distribution of a front and rear wheel steering angle change w and a braking force equivalent to a steering amount δ is input, and a yaw angular velocity γ and a weighted front and rear wheel slip angle z are output. It is a mathematical model that represents the motion of the vehicle that includes as a parameter. Also, P
0yaw (vx) represents equations (2) and (7), and is the target of the vehicle including the vehicle speed vx with the steering wheel operation amount δ as input and the target yaw angular velocity γ0 that is the target state amount of the vehicle as output. It is a mathematical model expressing motion.

By the way, discussing the stability of the control system shown in FIG. 8 is equivalent to discussing the stability of the control system which does not include the steering wheel steering amount δ and the target state amount shown in FIG. 9. For this reason, a controller is designed using the control system shown in FIG. In this case, it is assumed in FIG. 8 that the steering wheel steering amount is zero.

Here, in the control system shown in FIG. 9, in order to stabilize the closed loop system including arbitrary fluctuations Δf and Δr having an absolute value of 1 or less, the front and rear wheel steering angle changes as in the first embodiment. Structured singular value from w to front and rear wheel slip angle z is 1
It suffices to configure the control system so that it is less than. here,
The output feedback gain scheduling H∞ control theory is applied to the LPV system according to the above equations (3) and (4) to design the yaw angular velocity output feedback controller C (vx) adapted to the vehicle speed shown in the following equation (8). are doing.

Xc ′ = (θ1 · Ac1 + θ2 · Ac2 + θ3 · Ac3) · xc + (θ1 · Bc1 + θ2 · Bc2 + θ3 · Bc3) · (γ−γ0) u = (θ1 · Cc1 + θ2 · Cc2 + θ3 · Cc3) · xc + (θ1 + × θ + Dc1 + θ2 ・ Dc2 + θ3 ・ Dc3) ・ (γ-γ0) (8)

When this control law is used, the vehicle speed is v1≤v
It is possible to stabilize the vehicle motion even when it arbitrarily changes within the range of x ≦ v2. By the way, θ
1, θ2, θ3 have a relationship with the vehicle speed vx, and the control law of the equation (8) is configured to continuously change the gain according to the vehicle speed.

Next, the operation of this embodiment will be described. First, the sensor output of the steering angle sensor 11, the vehicle speed sensor 21, the yaw angular velocity sensor 32, the brake stroke operation amount sensor 61, and the ABS operation torque signal are used as the target state amount calculation means 40, the feedback amount calculation means 50, and the braking force distribution means 80. Is input to the digital computer that constitutes the.

In this digital computer, first,
The target state quantity computing means 40 computes the target yaw angular velocity γ0, which is the target state quantity of the vehicle, according to the recurrence formula obtained by discretizing the equations (2) and (7).

The target state quantity complies with the dynamic characteristics of the vehicle model when traveling at a constant vehicle speed on a high μ road having a margin of tire force characteristics. When there is no disturbance from the external environment such as side wind disturbance, the actual state quantity matches the target state quantity.

Next, in the feedback amount calculation means 50, the yaw moment required to bring the deviation between the actual state amount and the target state amount caused by fluctuations in the road surface condition, load movement, side wind disturbance, etc., to asymptotically approach zero. The feedback amount signal u which is the correction amount of is calculated according to the equation (8) based on the vehicle speed vx and the deviation between the actual state amount and the target state amount.
This feedback amount signal allows the dynamic characteristics of the vehicle state to follow the target dynamic characteristics within a physically possible range even when there is a disturbance or the like. Next, the basic distribution means 81 estimates the load distribution of each wheel and distributes the four-wheel braking torque target value signal to each wheel according to the load distribution. In this way, by matching the basic component of the braking force of each wheel with the load distribution, it is possible to uniformly exert the braking performance of each wheel and obtain excellent braking performance.

Next, the yaw moment correction means 82 corrects the control torque target value of each wheel according to the feedback amount u, so that the yaw moment of the feedback amount u is realized. When the ABS does not operate, the corrected braking torque target value for each wheel is transmitted to the control means 90 as a braking torque command value for each wheel, and the control means 90 controls each wheel based on the braking torque command value for each wheel. The braking is performed, and both the turning and braking characteristics intended by the driver and spin prevention are achieved.

When the ABS operates, the ABS correction means 83 sets the braking torque target value of each wheel based on the ABS operation torque signal in order to correct the fluctuation of the yaw moment due to the decrease of the braking torque of each wheel due to the ABS. It is corrected and output as a braking torque command value. This fix
The yaw moment of the feedback amount u is realized even during the ABS operation, and in this embodiment, the ABS
Even at the time of limit braking such that the vehicle operates, both the turning and braking characteristics intended by the driver and the prevention of spin are achieved within a physically possible range.

In the above embodiment, the case where the present invention is applied to the front wheel steering system has been described, but the present invention is not limited to this. A so-called 4WS known as a four-wheel steering system is linked to steering by a steering wheel to control rear wheel steering, so that the steering angle of each of the four wheels can be obtained from the steering angle and the vehicle speed. Therefore, the present invention can be applied to the four-wheel steering system by adding the rear wheel steering control means linked to the steering angle and the vehicle speed.

[0087]

As described above, according to the present invention, the variation of the cornering stiffness of the front wheels and the variation of the cornering stiffness of the rear wheels of the vehicle are based on the deviation between the target state quantity and the actual state quantity and the vehicle speed. The actual amount of state is prevented from diverging by calculating the feedback amount as a command value of at least one of the correction amount of the steering angle of the front wheels and the braking force control amount of each wheel so that the vehicle does not fall into the spin state. Since at least one of the steering control of the front wheels and the braking force control of each wheel is controlled based on this feedback amount, it is possible to keep the vehicle stable against changes in the cornering stiffness of the front and rear wheels. Therefore, the vehicle can run stably even under harsh driving conditions such as acceleration / deceleration and negative cornering force inclination, and spin prevention can be achieved. It is, there is an effect that.

[Brief description of drawings]

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

FIG. 2 is a block diagram showing a configuration of a control system including the device of the present invention.

FIG. 3 is a block diagram showing a configuration of a control system equivalent to the design of the feedback amount computing means of FIG.

FIG. 4 is a block diagram showing a configuration of an anti-spin control device according to the first embodiment of the present invention.

FIG. 5 is a block diagram showing a configuration of a control system including a device of the anti-spin control device of the first embodiment.

FIG. 6 is a block diagram showing a configuration of a control system equivalent to the design of the feedback amount calculation means of FIG.

FIG. 7 is a block diagram showing a configuration of an anti-spin control device according to the first embodiment of the present invention.

FIG. 8 is a block diagram showing a configuration of a control system including a device of the anti-spin control device of the first embodiment.

9 is a block diagram showing a configuration of a control system equivalent in design to the feedback amount calculating means in FIG. 8;

[Explanation of symbols]

 1 Steering amount detecting means 2 Vehicle speed detecting means 3 Actual state amount detecting means 4 Target state amount calculating means 5 Feedback amount calculating means 6 Control means

Continuation of front page (51) Int.Cl. ⁶ Identification number Reference number within the agency FI Technical display location B62D 137: 00 (72) Inventor Katsuhiro Asano Aichi-gun Nagakute-cho, Aichi-gun, Nagakute-cho 41, Yokomichi 1 Co., Ltd. Toyota Central Research Laboratory (72) Inventor Shigeyuki Hosoe 1-701 Motogo, Moriyama-ku, Nagoya, Aichi

Claims (2)

[Claims] 1. A steering amount detecting means for detecting a steering amount of a steering wheel of a vehicle, a vehicle speed detecting means for detecting a vehicle speed, and an actual state amount for detecting an actual state amount which is an actual turning amount state of the vehicle. A detection means; a target state quantity calculation means for calculating a target state quantity that is a target state quantity of the turning motion of the vehicle based on the vehicle speed and the steering quantity; and a deviation between the target state quantity and the actual state quantity. And the vehicle is prevented from falling into a spin state by preventing the actual state amount from diverging due to a change in the cornering stiffness of the front wheels and a change in the cornering stiffness of the rear wheels of the vehicle based on the vehicle speed. Feedback amount calculation means for calculating a feedback amount which is a command value of at least one of the correction amount of the steering angle of the front wheels or the rear wheels and the braking force control amount of at least one wheel; And control means for performing at least one of the control of the braking force control of the corrective steering control and at least one wheel of the steering angle of the front or rear wheels on the basis of the serial feedback amount, anti-spin control apparatus having a. 2. A method for setting a controller of a feedback amount calculation means in an anti-spin control device for a vehicle according to claim 1, wherein the cornering stiffness of the front wheels and the rear wheels is assumed to vary within a predetermined variation range. And a control system including a vehicle motion model simulating the motion of the vehicle and the feedback amount calculation means, the fluctuation is considered as a fluctuation in the steering angle of the front wheels and the rear wheels due to a fluctuation in the slip angle of the front wheels and the rear wheels. A closed loop, a step of converting the closed loop into a system in which the closed loop is replaced with an open loop, and structuring of slip angle fluctuations of the front wheels and rear wheels associated with fluctuations in the steering angle of the front wheels and rear wheels of the open loop. Setting the controller such that the singular value is less than 1 in all frequency regions. .