JPH1159366A - Driving force and braking force control device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To stabilize the running condition of a vehicle by anticipating the slip limit of a wheel through operations, and controlling according to the slip limit a braking force or driving force applied to the wheel. SOLUTION: A road surface friction coefficient μ generated on a wheel and a lateral force Fy generated on its axle are estimated through operations, and when the vertical load of the wheel is W, a maximum longitudinal force, Fxmax, is computed from the estimated road surface friction coefficient μand the lateral force Fy by using Fxmax=√[(μ/W)<2> -(Fy)<2> ] The driving force or braking force applied to the wheel is controlled according to the maximum longitudinal force Fxmax. Thus, hazardous conditions that may lead to the rolling of the vehicle can be prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is used by being mounted on an automobile. The present invention is used as a vehicle attitude control device. The present invention captures a value that can be measured by a running car, performs a real-time calculation by a program control circuit, and prevents a wheel from slipping, or a driving force or a driving force applied to a wheel while controlling the wheel's slip state. The present invention relates to a device for automatically controlling a braking force.

[0002]

2. Description of the Related Art When a large driving force is applied to a driving wheel on a slippery road surface, the driving wheel slips. At this time, the vehicle may spin in the lateral direction. The same applies to the case of braking. When a large braking force is applied to the wheels on a slippery road surface, the wheels are in a slip state and braking cannot be performed.
The loss of steering stability of the vehicle is often caused by the driving wheels starting to slip or the braking wheels starting to slip. Therefore, it is desirable to apply a driving force equal to or less than the slip limit so that the driving wheels do not slip when driving, and to apply a braking force equal to or less than the slip limit so that the braking wheels do not slip when braking. .

Conventionally, an electronic control device for a brake and a vehicle stability control device (VSC, Vehicle Stability Control) have been proposed.
Etc. are known. ABS (Antilock Brake System) is a typical system for electronic control devices related to brakes.
It is. This is to provide a rotation sensor on the wheel to detect the wheel rotation, and when the wheel rotation stops when the brake pressure is large, assuming that there was a slip between the wheel and the road surface,
The brake pressure is intermittently controlled. ABS has become widespread in passenger cars and freight cars, and has become widely known as a device that can handle while braking. As a typical device of the vehicle stabilization control device (VSC), a skid prevention device is known. This means that the course the driver is going to travel is read from the steering angle (steering angle) input by the driver, and if the vehicle speed is too high for that course, the driver will automatically enter without having to press the brake pedal. This is a device in which control for deceleration is performed and control such as distributing left and right brake pressures so as not to deviate from the course is performed.

[0004] A known vehicle attitude stabilizing device (VSC) (JP-A-63-279976, JP-A-2-112755, etc.) will be further described. When this is done, the direction of the vehicle changes and the vehicle rolls. At this time, when the tire of the turning inner wheel due to steering reaches the grip limit of the road surface, the inner wheel tends to be a so-called wheel lift, and the vehicle starts to skid. For example, when the driver steers to the left from a straight running state, the vehicle leans to the right. At this time, the vehicle turns in accordance with the steering in a normal state, but if the steering speed is too high relative to the traveling speed, the vehicle leans to the right and the left wheel is in a floating state, so that the driver Will move to the right from the intended direction. Such a behavior of the vehicle causes a deviation from the traveling lane or, in an extreme case, a rollover of the vehicle.

[0005] In a normal running state, the magnitude and speed of steering, the speed of the vehicle, the speed of lateral movement of the vehicle, and the speed of change in the direction of the vehicle (yaw rate, rotational acceleration of the vehicle around the vertical axis) are detected. A device has been developed which predicts the starting point of a skid of a wheel or the starting point of a wheel lift of an inner wheel by controlling the brake pressure of the wheel before the skid or the wheel lift starts. The brake pressure control of the wheels does not necessarily apply the same brake pressure to all the wheels, but applies a large or small brake pressure to one wheel to prevent the vehicle from skidding. Such an apparatus has been well studied not only for its basic structure and design, but also for its economy and durability, and has reached the stage of being mounted on a commercial product for a passenger car.

[0006] Such a conventional apparatus calculates a yaw rate from parameters related to the current driving operation including steering and braking and parameters related to the current behavior of the vehicle, that is, from the current parameters, and this is calculated in advance for the vehicle. When it is determined that the yaw rate having the possibility of the sideslip that has been set and stored is reached, the brake pressure of the vehicle is automatically controlled. The possibility of the side slip is determined by executing a calculation from the driving operation input and the vehicle behavior data as various sensor outputs.

[0007]

The prior art described above is
Both are devices that take in behavior data of the vehicle and automatically control it to stabilize the running of the vehicle, but do not predict the braking force or the driving force in which the wheels slip in advance when performing braking or driving .

The present invention has been made in such a background, and predicts and calculates a slip limit of a wheel so as to prevent a wheel from slipping or to control a slip state of a wheel while applying a braking force or a driving force. It is an object of the present invention to provide a method and an apparatus for vehicle stabilization control capable of giving power. An object of the present invention is to provide an automatic control device that stabilizes a running state of a vehicle. SUMMARY OF THE INVENTION An object of the present invention is to provide a stabilization control device that prevents a dangerous state that may lead to a rollover of a vehicle.

[0009]

According to the present invention, control information measurable during running of a vehicle is taken, a slip limit is calculated in real time by a program control circuit, and the calculated slip limit is given to wheels so that no slip occurs on the wheels. It is characterized by automatically controlling the driving force or the braking force and stabilizing the running state of the vehicle.

That is, the present invention provides a means for estimating and calculating a road surface friction coefficient μ generated on a wheel, a means for estimating and calculating a lateral force Fy generated on the wheel, and a lateral force estimated and calculated by the two means. Means for calculating the maximum longitudinal force Fxmax as Fxmax = √ [(μW) ² − (Fy) ² ] from Fy and the road surface friction coefficient μ assuming that the vertical load of the wheel is W; Means for controlling a driving force or a braking force applied to the wheel based on the driving force.

The means for estimating and calculating the lateral force Fy includes a lateral acceleration g captured from a lateral acceleration sensor mounted on the vehicle, a vehicle speed V captured from a wheel rotation sensor of the vehicle, a yaw rate ω captured from a yaw rate sensor of the vehicle,
And a means for calculating the lateral force Fy from an output road surface friction coefficient μ of the means for estimating and calculating the road surface friction coefficient. Further, the means for controlling the braking force includes a longitudinal force applied to the wheel from the road surface. Fx is the maximum longitudinal force Fxmax
Means for controlling the braking pressure so as not to exceed the maximum longitudinal force Fxmax such that the longitudinal force Fx applied to the wheels from the road surface does not exceed the maximum longitudinal force Fxmax. And means for controlling the braking pressure over time so that the longitudinal force Fx applied to the wheel from the road surface repeatedly reciprocates between a value exceeding the maximum longitudinal force Fxmax and a value not exceeding the maximum longitudinal force Fxmax. .

When a road surface friction coefficient μ generated on a wheel and a lateral force Fy generated on the wheel are estimated and calculated, and a vertical load of the wheel is set to W based on the estimated calculated road surface friction coefficient μ and the lateral force Fy. Is calculated by the above equation. When a braking force or a driving force exceeding the calculated maximum longitudinal force Fxmax is applied, the sideslip increases, so the driving force or the braking force applied to the wheel is controlled based on this value.

The road friction coefficient μ generated on the wheels can be estimated and calculated when the vehicle is accelerating or braking.

That is, in the case of estimation calculation at the time of acceleration, the rotational speeds of the left and right drive wheels and the driven wheels are detected and recorded, and the rotational speed difference between the left and right drive wheels is calculated. Calculate the time derivative. Next, a time at which the time differential value calculated in a time section of interest within the time period during which acceleration is performed indicates the maximum value is obtained, and the rotational acceleration of the driven wheel at a time slightly before this time is calculated. The value of the road surface friction coefficient μ is estimated and calculated in accordance with the maximum value of the time differential value of the rotational speed difference with respect to the rotational acceleration of the vehicle.

In the case of the estimation calculation at the time of braking, the rotational speeds of a plurality of braked wheels are detected and recorded, and ABS (Antilock B) is applied to the braking operation input.
rakeSystem: Calculates the time differential value of the rotation speed of the wheel on which the automatic braking control device has operated and the time differential value of the rotation speed of the wheel on which the ABS does not operate. Next, the value of the road surface friction coefficient μ is estimated and calculated in accordance with the negative amplitude value of the time differential value of the rotational speed of the wheel on which the ABS is activated with respect to the time differential value of the rotational speed of the wheel on which the ABS is not activated.

The lateral force Fy generated on the wheels takes the lateral acceleration g from the lateral acceleration sensor, the vehicle speed V from the wheel rotation sensor, and the yaw rate ω from the yaw rate sensor as measured values of the vehicle behavior. And the road friction coefficient μ calculated and estimated.

The braking force is the longitudinal force Fx applied to the wheels from the road surface.
Is controlled so as not to exceed the calculated maximum longitudinal force Fxmax, it is possible to prevent an increase in the side slip of the wheel during braking.

In addition, by controlling the driving force so that the longitudinal force Fx applied to the wheel from the road surface does not exceed the maximum longitudinal force Fxmax, it is possible to prevent the occurrence of side slip of the wheel during driving.

Since the braking force of the vehicle provided with the ABS is controlled automatically, the longitudinal force Fx applied to the wheel from the road surface repeatedly reciprocates between a value exceeding a maximum value Fxmax and a value not exceeding the maximum value Fxmax. In this way, the braking pressure is controlled over time. This can prevent the vehicle from skidding.

As described above, the maximum longitudinal force Fxm of the wheel determined by the vertical load W and the road surface friction coefficient μ of the vehicle.
Applying a braking force or a driving force within the value of the maximum longitudinal force with respect to ax, braking or driving within the slip limit of the wheel is automatically performed, and a dangerous condition that leads to a rollover of the vehicle Can be prevented beforehand.

[0021]

BEST MODE FOR CARRYING OUT THE INVENTION

[0022]

Next, an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a block diagram illustrating a configuration of a main part of a vehicle stabilization control device according to an embodiment of the present invention, FIG. 2 is a diagram illustrating a system configuration of a vehicle stabilization control device according to the embodiment of the present invention, and FIG. It is a perspective view showing the example of mounting in the vehicle of various sensors concerning the example device of the present invention.

The driving force braking force control device 1 of the embodiment of the present invention
An automatic braking control device (ABS) 2 is provided in a vehicle stabilization control device 3 mounted thereon.

The driving force braking force control device 1 includes wheels 1
The road surface friction coefficient estimating device 4 is provided as means for estimating and calculating the road surface friction coefficient μ generated in the vehicle 1. The means for estimating and calculating the lateral force Fy generated on the wheels 11 thereof, and the estimated and calculated lateral force Fy and road surface friction When the vertical load of the wheel is W from the coefficient μ, means for calculating the maximum longitudinal force Fxmax as Fxmax = と き [(μW) ^2- (Fy) ² ] is applied to the wheel based on the maximum longitudinal force Fxmax. Means for controlling the applied driving force or braking force.

The means for estimating and calculating the lateral force Fy includes the vehicle 1
1, the lateral force Fy from the lateral acceleration g taken from the lateral acceleration sensor 5 mounted on the vehicle 1, the vehicle speed V taken from the wheel rotation sensor 6, the yaw rate ω taken from the yaw rate sensor 7, and the output road friction coefficient μ of the road friction coefficient estimating device 4. Means for calculating is included.

The means for controlling the braking force includes the wheels 1
1 includes means for controlling the braking pressure such that the longitudinal force Fx applied from the road surface does not exceed the maximum longitudinal force Fxmax, and the means for controlling the driving force includes the longitudinal force Fx applied to the wheels 11 from the road surface. Means for controlling the engine driving force so as not to exceed Fxmax is included. Further, the means for controlling the driving force includes a value in which the longitudinal force Fx applied to the wheels 11 from the road surface in response to the control of the automatic braking control device (ABS) 2 is between a value exceeding the maximum longitudinal force Fxmax and a value not exceeding the maximum longitudinal force Fxmax. Means for controlling the braking pressure over time so as to make reciprocal reciprocations are included.

The vehicle stabilization control device 3 includes a longitudinal acceleration sensor 8, a roll rate sensor 9, a steering wheel 10
A steering angle sensor 12 for detecting a steering angle of the vehicle, a brake pressure sensor 14 for detecting a brake pressure of a brake booster actuator 13, and a detection output from a governor sensor 16 provided in the electronic governor 15 are connected.

FIG. 1 shows an example of a vehicle having a two-axis structure. In the case of a large vehicle, a three- or four-axis structure is used.
In the case of a vehicle having a three-axis or four-axis structure, each sensor is mounted on each wheel and the same control is performed.

Next, the operation of the thus-configured embodiment of the present invention will be described. FIG. 4 is a flowchart showing a flow of a control operation by the driving force braking force control device according to the embodiment of the present invention, and FIG. 5 is a diagram explaining a control operation by the driving force braking force control device according to the embodiment of the present invention.

The driving force braking force control device 1 takes in the road surface friction coefficient μ estimated and calculated by the road surface friction coefficient estimating device 4 and obtains the lateral acceleration g, the lateral acceleration g from the lateral acceleration sensor 5, the wheel rotation sensor 6, and the yaw rate sensor 7. The vehicle speed V and the yaw rate ω are taken.

The time differential value of the side slip angle β is calculated based on the acquired lateral acceleration g, vehicle speed V and yaw rate ω.

[0032]

(Equation 1) Is calculated. The time derivative of the sideslip angle β [1] is

[0033]

[Outside 1]

[0034]

(Equation 2) In a relationship.

Next, the time integrated value of the calculated time differential value [1] of the slip angle β is calculated.

[0036]

(Equation 3) Is calculated, and the generated lateral force Fy is obtained by the following equation.

Fy = μ · K _F · β _F β _F = β + (l _F · ω) / V K _F : constant (corner power of tire: known data) l _F : length from center of gravity to front axis _{, F y = μ · K F} (β + l F · ω / V) further, in order to determine the longitudinal force of the slip occurrence that can wheel, determine the friction circle limit R = .mu.W. In the case of a passenger car or a small car, the vertical load W is constant because the ratio of the loaded weight to the body weight is small, and in the case of a large truck or a bus, the vertical load W is measured by a weight measuring means (not shown).

Here, the maximum longitudinal force Fxmax is calculated by the following equation.

Fxmax = √ [(μW) ^2- (Fy) ² ] = √ [(μW) ^2- (μK _F β _F ) ² ] Driving force or braking force applied to wheels 11 based on this maximum longitudinal force Fxmax Control. That is, when controlling the braking force, the braking pressure is controlled such that the longitudinal force Fx applied to the wheels 11 from the road surface does not exceed the maximum longitudinal force Fxmax.

FIG. 6 is a diagram for explaining braking control on a road surface having a high road friction coefficient μ. This example shows a state in which the vehicle is steered to the right. It is assumed that a lateral force Fy is generated by the steering and a spin is generated thereafter. Therefore, when the braking force is applied to generate a longitudinal force Fx on the wheels 11 so as not to exceed Fxmax, a moment in the opposite direction to the spin is applied to the vehicle, and the lateral force Fy is reduced, thereby preventing the occurrence of the spin. On a road surface having a high road friction coefficient μ, the friction circle of the vehicle becomes large. Therefore, the braking force is applied to the driven wheels and the drive wheels, and the maximum longitudinal force Fxmax such that the lateral force Fy enters the friction circle. Control to prevent occurrence of spin.

FIG. 7 is a diagram for explaining braking control on a road surface having a low road friction coefficient μ. On a road surface with a low coefficient of friction μ, the friction circle of the vehicle becomes smaller, so the braking circle is not applied to the drive wheels and the friction circle is used as a cornering force (a force perpendicular to the traveling direction acting on the wheels on the road surface). It is used to the maximum extent and the occurrence of spin is prevented by the yaw moment due to the maximum longitudinal force Fxmax of the driven wheel.

When the driving force is controlled, the longitudinal force Fx applied to the wheels 11 from the road surface by the same principle becomes the maximum longitudinal force Fxm.
The engine driving force is controlled so as not to exceed ax to prevent the occurrence of slip or spin.

In the control of the driving force, when the control by the automatic braking control device (ABS) 2 is performed, the longitudinal force Fx applied to the wheels 11 from the road surface is set between a value exceeding the maximum longitudinal force Fxmax and a value not exceeding the maximum longitudinal force Fxmax. Is controlled over time so as to repeatedly reciprocate. This makes it possible to reasonably cope with the automatic braking control.

Here, a method for estimating the road friction coefficient μ generated on the wheels 11 by the road friction coefficient estimation device 4 according to the embodiment of the present invention will be described. The calculation for estimating the road surface friction coefficient μ is performed when the vehicle is accelerating or braking.

First, the estimation calculation during vehicle acceleration will be described. The road surface friction coefficient estimating device 4 detects the rotational speeds (ωrl · ωr
r) and the rotational speed (ωf) of the driven wheel are recorded and recorded,
The rotation speed difference (ωrl-ωrr) of the left and right driving wheels is calculated, and the time differential value [d (ωrl-ωrr) / dt] of the rotation speed difference (ωrl-ωrr) is calculated.

Next, a time (ts) at which this time differential value shows the maximum value (a) is obtained in a time section of interest within the time period in which the acceleration by the engine drive is being performed.
The rotational acceleration (dωf / dt) of the driven wheel at a time (ts−Δt) slightly before (s) is calculated.

The road surface friction coefficient estimating device 4 has a maximum value (a) corresponding to the rotational acceleration (dωf / dt) of the driven wheel corresponding to the stepwise divided value of the road surface friction coefficient μ according to the characteristics of the vehicle. There is provided a map stored in advance for the size of. Referring to this map, the road surface friction coefficient μ is estimated corresponding to the rotational acceleration (dωf / dt) of the driven wheel and the magnitude of the maximum value (a).

Next, the estimation calculation at the time of vehicle braking will be described. The road surface friction coefficient estimating device 4 captures and records the wheel rotation speeds (ωp, ωq) of a plurality of wheels during braking from the wheel rotation sensor 6, and operates the automatic braking control device (ABS) 2 in response to a braking operation input. Differential value (dωq / d) of the rotational speed (ωq) of the wheel (Q)
t) is calculated.

Next, the automatic braking control device (ABS) for the time differential value (dωp / dt) of the rotation speed (ωp) of the wheel (P) in which the automatic braking control device (ABS) 2 does not operate.
The negative amplitude value (a ′) of the time differential value (dωq / dt) of the rotation speed (ωq) of the wheel (Q) on which the wheel 2 operates is obtained.

In the map, the wheels (P) on which the automatic braking control unit (ABS) 2 does not operate corresponding to the stepwise divided values of the road surface friction coefficient μ according to the characteristics of the vehicle.
Differential value (dωq / d) of the rotational speed (ωq) of the wheel (Q) on which the automatic braking control device (ABS) 2 operates with respect to the time differential value (dωp / dt) of the rotational speed (ωp) of the vehicle
Since the magnitude of the negative amplitude value (a ') of t) is stored in advance, referring to this map, the rotation speed (ωp) of the wheel (P) in which the automatic braking control device (ABS) 2 does not operate. Is calculated from the time differential value (dωp / dt) and the negative side amplitude value (a ′).

Next, the vehicle stabilization control by the vehicle stabilization control device 3 relating to the driving force braking force control device according to the embodiment of the present invention will be described.

As shown in FIG. 1, the vehicle stabilization control device 3
As the data indicating the behavior of the vehicle, vehicle speed, lateral acceleration, yaw rate, roll rate, wheel rotation speed, and other control information are input from sensors provided in the vehicle. The vehicle stabilization control device 3 predicts and calculates the behavior of the vehicle using the driving operation input and these behavior data as input, and supplies the result to the automatic braking control device (ABS) 2. The automatic braking control device 2 also takes in the driving operation input and the behavior data, and also takes in the output of the driving force braking force control device 1 and sends out the automatic control output in the safe direction for the driving operation input and the disturbance input to the vehicle. I do. This is a correction input.

The vehicle stabilization control device 3 includes a numerical model that holds the physical characteristics of the vehicle as numerical values, a driving operation input of the vehicle as data, and a state of the vehicle by a transfer function with reference to the numerical model. The data given to the transfer function is obtained by adding data X (k) at time k to past data up to the time M before weighting coefficient A (m) at each time. Means for calculating a response by an autoregressive method (AR method) represented by a value multiplied by

According to the weight, the center of gravity, the wheelbase, and other various parameters held in the numerical model, a comparison operation is executed, and the possibility of occurrence of front wheel side slip, rear wheel side slip, wheel lift, and the like is calculated. . When the possibility of occurrence exceeds a predetermined reference, the control amount to be performed on the safe side is calculated, and the calculation result is transmitted to the automatic braking control device (ABS) 2.

The automatic braking controller (ABS) 2 calculates a correction amount by summing up the calculation results, and supplies this to the vehicle as a correction input. Specifically, for example, braking is performed only on the rear left wheel, or braking is performed on all the wheels but the braking amount on the front right wheel is controlled to be small.

Further, when the behavior estimated by the observer does not match the actual behavior observed by the sensors 11 provided on the vehicle, some of the parameters relating to the characteristics of the vehicle set in the numerical model are set. Update automatically. For example, when the load weight changes, when the load appearance changes, when the number of passengers changes, or when the seating position of the passenger changes, the parameters indicating the characteristics of the vehicle are different from the actual behavior. I will not do it. At this time, the parameters stored in advance in the numerical model of the vehicle are automatically changed to match the behavior.
This update is executed when the vehicle is running safely, in which the behavior of the vehicle in response to a driving operation input or a disturbance input is sufficiently smaller than a dangerous level.

An example of a control flow by the vehicle stabilization control device 3 is as shown in FIG. 8 for normal control. The acquisition of the behavior data is executed by an auto-regression method (AR method). That is, the data up to the point in time before the past M is reversed, and is represented by a value obtained by multiplying the past data by the weighting coefficient A (m) for each point in time.

When the state of the cargo changes or the number of passengers or the position of the passenger changes, the control illustrated in FIG. 9 is performed, and the parameters of the vehicle model are updated. This update is automatically performed by always monitoring whether or not a correction is required. The acquisition of the behavior data is also executed by the auto-regression method (AR method). The process in the update mode shown in FIG. 9 is executed in step S9 shown in FIG.

FIG. 10 shows an example of input data of the vehicle stabilization control device 3 according to the embodiment of the present invention.
(A) shows the steering angle, (b) shows the yaw rate, and (c) shows the sideslip angle. The horizontal axis is time (seconds).
The horizontal axis is common to (a), (b) and (c). When the steering wheel 10 is operated, the steering angle sensor 12 detects this, and sends the input data shown in FIG. Along with this steering operation, the yaw rate sensor 7 detects the yaw rate and sends the input data shown in (b) to the vehicle stabilization control device 3. At the same time, lateral acceleration sensor 5
Detects the sideslip angle and sends the input data shown in (c) to the vehicle stabilization control device 3. That is, (a) shown in FIG. 10 is an input, and (b) and (c) are responses representing the behavior (behavior) of the vehicle.

The vehicle stabilization control device 3 calculates the transfer function of the vehicle based on these data. The transfer function is a complex function. In a practical example, the transfer function can be displayed by displaying the frequency on the horizontal axis and the amplitude and phase on the vertical axis. Assuming a relatively simple model, the amplitude characteristic has a gentle downward slope curve with respect to the frequency, and the phase characteristic has a corresponding downward slope curve. FIG.
(A) And (b) is a figure which illustrates the frequency characteristic of an amplitude and a phase about a yaw rate. FIGS. 12A and 12B are diagrams illustrating the frequency characteristics of the amplitude and the phase with respect to the sideslip angle. These are diagrams showing transfer functions calculated based on actual data.

Here, the attitude control and update of the vehicle will be described. When the transfer function is determined in this manner, the dynamic characteristics of the vehicle are calculated using the transfer function, and when an abnormal movement exceeding a predetermined standard is predicted,
Attitude control is performed by applying a different brake pressure to each wheel to suppress abnormal movement of the vehicle. This is the same as a method that has been practically used for passenger cars, and a detailed description thereof will be omitted here. This technology is applied to a commercial vehicle (truck / bus). In a commercial vehicle, the transfer function itself representing the response of the vehicle varies depending on the status of cargo, the number of passengers, and the like. Therefore, the transfer function is updated.

FIG. 11 is a diagram for explaining this, and it is assumed that a function having a characteristic indicated by a broken line is already stored as a transfer function in a numerical model. This is a model when the load is in a standard form of about one third of the maximum load capacity.
Suppose that a new additional load is loaded. Then, both the total weight and the position of the center of gravity change. This naturally results in a different response of the vehicle to the same steering. That is, the transfer function already stored must be changed. Therefore, when the transfer function is newly calculated according to the behavior of the vehicle appearing in the sensor, a characteristic different from the transfer function already stored appears as shown by a solid line. This calculation is automatically executed as described with reference to FIG. When the difference, that is, the area to be hatched in FIG. 11 is larger than a preset limit value,
As shown by the solid line, the stored model itself is updated to a new calculated value indicating the current state. This is performed automatically as described in FIG. By updating such a numerical model of the automatically accumulated transfer function, it becomes possible to execute appropriate attitude control even when the load changes or the number of passengers changes. .

[0063]

As described above, according to the present invention, the braking force or the driving force is calculated by predicting and calculating the slip limit of the wheel so as not to cause slip on the wheel or controlling the slip state of the wheel. This can stabilize the running state of the vehicle and prevent a dangerous state that may lead to rollover.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of a main part of a vehicle stabilization control device according to an embodiment of the present invention.

FIG. 2 is a diagram showing a system configuration of a vehicle stabilization control device according to the embodiment device of the present invention.

FIG. 3 is a perspective view showing an example of mounting various sensors according to the embodiment of the present invention on a vehicle.

FIG. 4 is a flowchart showing a control operation flow by the driving force braking force control device according to the embodiment of the present invention;

FIG. 5 is a diagram illustrating a control operation by the driving force braking force control device according to the embodiment of the present invention.

FIG. 6 is a diagram illustrating braking control on a road surface having a high road surface friction coefficient μ.

FIG. 7 is a view for explaining braking control on a road surface having a low road surface friction coefficient μ.

FIG. 8 is a flowchart illustrating normal control by the vehicle stabilization control device according to the embodiment device of the present invention.

FIG. 9 is a flowchart illustrating updating of a vehicle model parameter by the vehicle stabilization control device according to the embodiment of the present invention.

FIGS. 10A, 10B, and 10C are diagrams showing input data of a steering angle, a yaw rate, and a sideslip angle of a vehicle stabilization control device according to the embodiment of the present invention.

FIGS. 11A and 11B are diagrams illustrating an example of a transfer function represented by a gain and a phase of a vehicle stabilization control device according to the embodiment device of the present invention.

12A and 12B are diagrams showing another example of the transfer function represented by the gain and the position of the vehicle stabilization control device according to the embodiment of the present invention.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 driving force braking force control device 2 automatic braking control device (ABS) 3 vehicle stabilization control device 4 road surface friction coefficient estimation device 5 lateral acceleration sensor 6 wheel rotation sensor 7 yaw rate sensor 8 longitudinal acceleration sensor 9 roll rate sensor 10 steering wheel DESCRIPTION OF SYMBOLS 11 Wheel 12 Steering angle sensor 13 Brake booster actuator 14 Brake pressure sensor 15 Electronic governor 16 Governor sensor

Continuation of the front page (51) Int.Cl. ⁶ Identification code FI F02D 41/04 310 F02D 41/04 310G (72) Inventor Fujio Koyama 3-1-1, Hinodai, Hino-shi, Tokyo Inside Hino Motors, Ltd. (72) Inventor Hirokazu Okuyama 3-1-1, Hinodai, Hino-shi, Tokyo Inside Hino Motors, Ltd.

Claims (5)

[Claims] 1. A means for estimating and calculating a road surface friction coefficient μ generated on a wheel, a means for estimating and calculating a lateral force Fy generated on a wheel, and a lateral force Fy and a road surface friction estimated and calculated by the two means. When the vertical load of the wheel is W from the coefficient μ, means for calculating the maximum longitudinal force Fxmax as Fxmax = と き [(μW) ^2- (Fy) ² ] is applied to the wheel based on the maximum longitudinal force Fxmax. Means for controlling the driving force or the braking force to be applied. 2. The means for estimating and calculating the lateral force Fy includes a lateral acceleration g captured from a lateral acceleration sensor mounted on the vehicle, a vehicle speed V captured from a wheel rotation sensor of the vehicle,
2. The driving force braking force control device according to claim 1, further comprising means for calculating the lateral force Fy from a yaw rate ω taken from a yaw rate sensor of the vehicle and an output road surface friction coefficient μ of the means for estimating and calculating the road surface friction coefficient. 3. The driving force control device according to claim 2, wherein said means for controlling the braking force includes means for controlling the braking pressure such that the longitudinal force Fx applied to the wheels from the road surface does not exceed the maximum longitudinal force Fxmax. Power control device. 4. The driving force according to claim 2, wherein the means for controlling the driving force includes means for controlling the engine driving force such that the longitudinal force Fx applied to the wheels from the road surface does not exceed the maximum longitudinal force Fxmax. Control device for braking force. 5. The means for controlling the driving force includes a braking pressure for a time so that the longitudinal force Fx applied to the wheel from the road surface repeatedly reciprocates between a value exceeding the maximum longitudinal force Fxmax and a value not exceeding the maximum longitudinal force Fxmax. 3. The control device for a driving force braking force according to claim 2, further comprising means for controlling the driving force in accordance with the progress.