JP2001050973A - Method and device for estimating and for controlling behavior of vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To accurately estimate the overturning tendency of a vehicle at earlier timing corresponding to the actual behavior of the vehicle. SOLUTION: First, the roll angle ϕ0 and roll flexibility ϕ0, both indicating the actual overturning tendency of a running vehicle are measured (calculated) (S120 and S130). Then the maximum amplitude A (estimating value) of the roll angle is calculated by using the measured values, based on an operational expression for estimating the maximum amplitude A before an estimated behavior value ϕ(t) attenuates deduced from a physical model, Jϕ"+Dϕ'+Kϕ=F (where, J, D and K respectively represent inertia or roll, damping constant, and spring constant and F, ϕ", and ϕ' respectively represent centrifugal force, differentiated value of the roll flexibility, and roll flexibility) expressing the behavior of the vehicle, based on the roll angle ϕ indicating the overturning tendency of the vehicle and used as an overturning parameter X indicating the overturning tendency of the vehicle (S140).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and an apparatus for estimating a vehicle behavior for estimating a fall parameter representing the ease of a vehicle fall when the vehicle is running, and a vehicle behavior estimation method and apparatus using the method and apparatus for estimating a vehicle behavior. The present invention relates to a vehicle behavior control method and device for preventing a vehicle from overturning.

[0002]

2. Description of the Related Art Heretofore, the possibility of a vehicle overturning (rolling over) when the vehicle is running, for example, when turning, is estimated using a overturning parameter representing the ease of overturning (overturning) of the vehicle. 2. Description of the Related Art There is known a vehicle behavior control device that controls a braking force applied to each wheel in accordance with the control to prevent the vehicle from overturning (rolling over).

[0003] As a conventional vehicle behavior control device, for example, there has been a device using lateral acceleration acting on a vehicle as the above-mentioned overturn parameter. In this vehicle behavior control device, a lateral acceleration (falling parameter) detected by a lateral acceleration sensor or the like attached to the vehicle is a predetermined value (for example,
If the vehicle exceeds 1 G), it is determined that the vehicle is likely to overturn (roll over) (in other words, the roll angle of the vehicle is excessive), and the braking force on each wheel is automatically controlled to cause the vehicle to overturn. (Rollover) is prevented. More specifically, for example, a braking force is applied to the front wheels on the turning outer wheel side of the vehicle to make the running state of the vehicle tend to understeer, thereby preventing the vehicle from overturning (rolling over).

[0004] However, if control is performed using the lateral acceleration as a fall parameter, control of the vehicle that does not fall (roll over) even when the lateral acceleration exceeds 1 G becomes meaningless. In other words, when the lateral acceleration exceeds 1 G (it may be even lower depending on the road surface), the grip force of the wheels on the road surface is weakened, and the vehicle rolls (that is, falls (rolls over)) any more. Will not join. Normally, in this case, the front wheels of the vehicle cannot maintain the original turning course and cause a side slip,
The running state of the vehicle tends to understeer. Therefore,
When the control using the lateral acceleration as a fall parameter is performed, a vehicle that does not fall (laterally roll) even when the lateral acceleration exceeds 1 G and only causes a side slip is overturned when the lateral acceleration exceeds 1 G ( The ease of rollover, that is, the possibility of the vehicle falling over (rollover) cannot be accurately represented by the overturn parameter, so that the control becomes meaningless.

Accordingly, the present applicant has filed an application for a vehicle behavior control device using the amount of change in the rotation speed of the wheels as the above-mentioned overturn parameter (Japanese Patent Application No. 11-72568).

[0006] In this vehicle behavior control device, the turning in the case where the turning inner wheel is not floating off the road surface is determined from the actual rotation speed of the turning outer wheel and the actual lateral acceleration acting on the vehicle, in which the wheels are sufficiently gripped on the road surface. The rotation speed of the inner wheel is calculated as an estimated value, and the absolute value of the difference between the estimated value and the actual rotation speed of the turning inner wheel is calculated as a fall parameter,
Used.

At this time, when the turning inner wheel is floating above the road surface, there is no friction between the turning inner wheel and the road surface. When the accelerator operation or the brake operation is performed by the driver, the change becomes extremely constant. Therefore, in any case, the overturn parameter becomes large.

In this vehicle behavior control device, the vehicle can overturn (roll over) when the overturn parameter becomes larger than a predetermined threshold value, that is, when it is detected that the turning inner wheel floats off the road surface. Judgment is high,
As in the above-described conventional vehicle behavior control device, the braking force on each wheel is automatically controlled to prevent the vehicle from overturning (rolling over).

In other words, this vehicle behavior control device differs from the above-described conventional vehicle behavior control device only when the turning inner wheel floats off the road surface, that is, only when the control for preventing overturn (rollover) is really necessary. Apply braking force to a given wheel,
This prevents the vehicle from overturning (rolling over).

[0010]

However, if the control for preventing overturn (rollover) is started after the turning inner wheel floats as described above, for example, when the vehicle performs lane change running, the timing is delayed. In some cases, it was not possible to sufficiently prevent the vehicle from overturning (rolling over).

That is, first, when the vehicle performs a lane change run, the driver switches the steering before and after the lane change, and therefore, as shown in FIG. For example, a vehicle that has rolled in the direction opposite to the steering direction (in FIG. 9, shown as a roll angle φ and a roll rate φ ′ in the vehicle) further rolls in the opposite direction, and A reversal phenomenon occurs in which the direction of action of the centrifugal force F is also in the opposite direction.

The amplitude (magnitude) of the swingback becomes particularly large when the timing of the swingback and the timing of the steering operation by the driver match. And
When the turning timing and the steering steering timing match in this way, even when the vehicle does not fall (roll over) even when the lateral acceleration becomes 1 G during normal turning,
At the same 1 G lateral acceleration, the vehicle is likely to overturn (roll over).

[0013] The swingback varies depending on the vehicle type and the degree of attenuation of the swingback, but is generated as a vibration of about 0.5 to 2 Hz. If the control for preventing overturn (rollover) is started after the wheel (wheel in the steering direction) floats, the timing is too late, and the overturn (rollover) of the vehicle may not be sufficiently prevented. That is, the timing may be too late if the magnitude of the overturn parameter changes only when the turning inner wheel (wheel in the steering direction) floats.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and an object of the present invention is to estimate the likelihood of a vehicle falling over accurately at an earlier timing in accordance with the actual behavior of the vehicle. Vehicle behavior estimation method and apparatus,
It is another object of the present invention to provide a vehicle behavior control method and apparatus for controlling a vehicle behavior based on the estimation result.

[0015]

According to the first aspect of the present invention, a roll angle and a roll rate of a vehicle are measured during running of the vehicle. . Then, the following physical model Jφ ″ + Dφ ′ + Kφ = F (where J: roll inertia, D: damper constant, K: spring constant, F: centrifugal force, φ) '': Roll rate differential value, φ ':
(Roll rate, φ: roll angle) Based on the calculation formula derived from the roll angle and roll rate,
An estimated value of a fall parameter representing the ease of falling of the vehicle is calculated.

That is, in the method of the present invention (claim 1), the vehicle behavior (falling behavior) is described based on the roll angle representing the tendency of the traveling vehicle to roll over (rollover). Using the roll angle and roll rate measurement results that represent the actual overturning (rollover) tendency of the traveling vehicle,
The fall parameter is calculated as an estimated value.

Therefore, according to the method of the present invention (claim 1), the overturn parameter is set to the actual vehicle behavior (overturn behavior).
Can be calculated as a value that increases or decreases in a stepwise manner, and the fallover parameter makes it possible to accurately estimate the likelihood of the vehicle falling over.

In other words, according to the method of the present invention (claim 1), the overturn parameter indicates the actual behavior of the vehicle from the time before the turning inner wheel (in the case of lane change running, the wheel on the steering direction side) floats. (Fall behavior)
Since it is calculated as a value that increases or decreases stepwise, it is possible to accurately estimate the ease of falling of the vehicle at an earlier timing before the turning inner wheel (in the case of lane change driving, the wheel on the steering direction side) floats. can do.

When actually calculating the overturn parameter, it is not always necessary to perform the calculation in which the measurement results of the roll angle and the roll rate are applied to the above-described arithmetic expressions. It is also possible to set a map for calculating the overturning parameter and the like, and to calculate using this.

As a specific mode of calculating the overturn parameter, for example, the above-mentioned arithmetic expression is an arithmetic expression for estimating the maximum amplitude of the roll angle, and based on this arithmetic expression, An estimated value of the maximum amplitude of the roll angle may be calculated, and the estimated value may be used as the overturn parameter.

That is, first, an arithmetic expression for estimating the behavior of the roll angle can be derived from the physical model. In this arithmetic expression for estimating the behavior of the roll angle, it is assumed that the estimated value of the roll angle undergoes a damped oscillation. However, in the method of the present invention (claim 2), the arithmetic expression for estimating the maximum amplitude of the roll angle derived from the arithmetic expression for estimating the roll angle behavior is the arithmetic expression for calculating the overturn parameter, A value obtained by applying the measurement result of the roll angle and the roll rate to this arithmetic expression is calculated as a fall parameter.

In this case, the overturn parameter is calculated as a value which is obtained by estimating the possibility of overturning (overturning) of the traveling vehicle, that is, the possibility of overturning (overturning) is always large (dangerous side). According to the second aspect, the possibility of the vehicle being overturned (rolling over) is accurately and accurately estimated at an earlier timing before the turning inner wheel (in the case of lane change running, the wheel on the steering direction side) floats. can do.

The arithmetic expression for estimating the roll angle behavior derived from the physical model and the arithmetic expression for estimating the maximum amplitude of the roll angle derived from the arithmetic expression for estimating the roll angle behavior are as follows. This will be described in detail in the following embodiments.

As another specific mode for calculating the overturning parameter, for example, the above-mentioned arithmetic expression is an arithmetic expression for estimating the behavior of the roll angle, and based on this arithmetic expression, Alternatively, an estimated value of the roll angle after a lapse of a predetermined time in consideration of a control delay in controlling the vehicle behavior may be calculated, and the estimated value may be used as a fall parameter.

That is, in the method of the present invention (claim 3), the calculation formula for estimating the behavior of the roll angle derived from the physical model is the calculation formula for calculating the overturn parameter, and the roll formula and the roll angle are included in the calculation formula. The value obtained by applying the rate measurement result is calculated as a fall parameter. Based on the fall parameter calculated in this way,
When actually controlling the vehicle behavior, a control delay occurs in the control system. Therefore, in the method of the present invention (claim 3), an estimated value of the roll angle after a lapse of a predetermined time in consideration of the control delay is determined by using the overturn parameter. Is calculated.

Therefore, according to the method of the present invention (claim 3), the estimated value of the roll angle at the time of actually controlling the behavior of the vehicle can be calculated as the overturn parameter, and the turning inner wheel (in the case of lane change traveling, , The wheel on the side of the steering direction),
It is possible to accurately estimate the possibility of the vehicle overturning (rolling over).

If the vehicle behavior control is performed based on the overturn parameter calculated as described above, appropriate vehicle behavior control corresponding to the actual vehicle behavior (fallover behavior) at the time of control can be performed.

As another specific mode for calculating the overturn parameter, for example, the above-mentioned arithmetic expression is an arithmetic expression for estimating the roll angle behavior, and based on this arithmetic expression, Then, an estimated value of the roll angle at the next maximum may be calculated, and this estimated value may be used as the overturn parameter.

That is, in the method of the present invention (claim 4), the calculation formula for estimating the behavior of the roll angle derived from the physical model is the calculation formula for calculating the overturn parameter, and the roll formula and the roll angle are included in the calculation formula. The value obtained by applying the measurement result of the rate is calculated as the overturning parameter. As described above, in the calculation formula for estimating the behavior of the roll angle, it is assumed that the estimated value of the roll angle is attenuated. Therefore, in the method of the present invention (claim 4), an estimated value of the roll angle when the roll angle becomes the next maximum is calculated as the overturning parameter based on the operation formula for estimating the behavior of the roll angle.

In this case, the overturn parameter is calculated as a value which is obtained by always estimating the possibility of overturning (overturning) of the traveling vehicle, that is, the possibility of overturning (overturning) to the maximum (risk side). According to the invention method (claim 4), the vehicle can easily fall over (overturn) accurately at an early timing before the turning inner wheel (in the case of lane change running, the wheel on the steering direction side) floats. Can be estimated.

On the other hand, the invention according to claim 5 is based on claim 1
The present invention provides a vehicle behavior estimating apparatus having a configuration for realizing the method according to the first aspect of the present invention. First, when the vehicle is running, a roll angle and a roll rate of the vehicle are measured by a vehicle state detecting unit. Next, the following physical model Jφ ″ + Dφ ′ + Kφ = F (where J is a roll inertia, D is a damper constant, and K is a spring) Constant, F: centrifugal force, φ ″: differential value of roll rate, φ ′:
Roll rate, φ: roll angle), and using the roll angle and roll rate measurement results measured by the vehicle state detection means, the rollover parameter representing the ease of falling of the traveling vehicle. Calculate the estimated value.

Therefore, according to the present invention (claim 5), the overturn parameter can be calculated as a value that increases and decreases stepwise in accordance with the actual behavior of the vehicle (overturn behavior). Thus, it is possible to accurately estimate the possibility of the vehicle falling over.

In other words, according to the present invention (claim 5), the overturn parameter is determined by the actual behavior of the vehicle (from the time before the turning inner wheel (in the case of lane change running, the wheel on the steering direction side) floats). It is calculated as a value that increases or decreases in a stepwise manner in accordance with the vehicle's tipping behavior. Can easily be estimated.

The invention described in claim 6 is the same as the invention described in claim 2.
A vehicle behavior estimating apparatus having a configuration for realizing the invention method described in (1), wherein the arithmetic expression is an arithmetic expression for estimating the maximum amplitude of the roll angle, and the overturning parameter estimating means uses the arithmetic expression Based on this, an estimated value of the maximum amplitude of the roll angle is calculated, and this estimated value is used as a fall parameter.

Therefore, according to the present invention (claim 6), the overturn parameter estimates the ease of overturning (overturning) of the traveling vehicle, that is, the possibility of overturning (overturning) is always large (dangerous side). Since this is calculated as a value, it is possible to accurately and easily estimate the ease of falling of the vehicle at an early timing before the turning inner wheel (the wheel in the steering direction in the case of lane change running) floats.

Next, the invention according to claim 7 is based on claim 3
A vehicle behavior estimating device having a configuration for realizing the invention method described in the above, wherein the arithmetic expression is an arithmetic expression for estimating the behavior of the roll angle,
Based on this arithmetic expression, an estimated value of the roll angle after a lapse of a predetermined time in consideration of a control delay in controlling the vehicle behavior is calculated, and this estimated value is used as a fall parameter.

Therefore, according to the present invention (claim 7), the estimated value of the roll angle at the time of actually controlling the behavior of the vehicle can be calculated as the overturning parameter. It is possible to accurately and easily estimate the likelihood of the vehicle falling over at an early timing before the wheel (the steering wheel in the steering direction) floats.

If the vehicle behavior control is performed based on the thus calculated overturn parameter, appropriate vehicle behavior control corresponding to the actual vehicle behavior (overturn behavior) at the time of control can be performed.

Next, an invention according to claim 8 is an invention of a vehicle behavior estimating device having a configuration for realizing the method according to claim 4, wherein the arithmetic expression is defined as a roll angle. The rollover parameter estimating means calculates an estimated value of the roll angle at the next maximum based on this arithmetic expression, and uses the estimated value as a fallover parameter.

Therefore, according to the present invention (claim 8), the overturn parameter estimates the ease of overturning (overturning) of the traveling vehicle, that is, the possibility of overturning (overturning) always to the maximum (dangerous side). Since it is calculated as a value, it is necessary to accurately and easily estimate the likelihood of the vehicle falling (rolling over) at an earlier timing before the inner wheel turning (in the case of lane change running, the wheel on the steering direction side) floats. Can be.

On the other hand, as a specific mode of measuring the roll angle and the roll rate of the traveling vehicle by the vehicle state detecting means, for example, the vehicle state detecting means may include a roll rate measuring means. Then, the roll rate of the vehicle is measured, and the roll angle is calculated by applying the measured roll rate to a physical model describing the relationship between the roll rate and the roll angle of the vehicle by the roll angle calculating means. You may comprise.

In this way, it is possible to measure the roll angle and the roll rate of the traveling vehicle used when calculating the overturn parameter.

In this case, a specific example of the roll rate measuring means may be a roll rate sensor mounted on a vehicle.

The physical model describing the relationship between the roll rate and the roll angle will be described in detail in the following embodiments.

Another specific mode in which the vehicle state detecting means measures the roll angle and the roll rate of the traveling vehicle is as follows. The measurement means measures the lateral acceleration of the vehicle, and the roll angle calculation means calculates the roll angle by applying the measured lateral acceleration to a physical model describing the relationship between the lateral acceleration and the roll angle of the vehicle. The roll rate calculating means may be configured to differentiate the calculated roll angle to calculate the roll rate of the vehicle.

Thus, the roll angle and roll rate of the traveling vehicle used when calculating the overturn parameter can be measured without using a roll rate sensor.

The physical model describing the relationship between the lateral acceleration and the roll angle will be described in detail in the following embodiments.

Another specific mode in which the vehicle state detecting means measures the roll angle and the roll rate of the traveling vehicle is as follows. Means for measuring the yaw rate of the vehicle, body speed measuring means for measuring the vehicle body speed, and roll angle calculating means for describing the relationship between the yaw rate and the vehicle speed and the roll angle of the vehicle. The roll angle may be calculated by applying the measured yaw rate and vehicle body speed to the vehicle, and the roll rate may be calculated by differentiating the calculated roll angle by a roll rate calculating unit.

Thus, the roll angle and the roll rate of the traveling vehicle used when calculating the overturn parameter can be measured without using the roll rate sensor.

The physical model describing the relationship between the yaw rate and the vehicle speed and the roll angle will be described in detail in the embodiments described later.

Another specific mode in which the vehicle state detecting means measures the roll angle and the roll rate of the traveling vehicle is as follows. The measuring means measures the steering angle of the vehicle, the vehicle speed measuring means measures the vehicle body speed, and the roll angle calculating means describes the relationship between the steering angle, the vehicle speed and the roll angle of the vehicle. A roll angle is calculated by applying the measured steering angle and vehicle body speed to the physical model obtained, and a roll rate calculating unit calculates the roll rate of the vehicle by differentiating the calculated roll angle. May be.

By doing so, the roll angle and roll rate of the traveling vehicle used when calculating the overturn parameter can be measured without using a roll rate sensor.

The physical model describing the relationship between the steering angle, the vehicle speed, and the roll angle will be described in detail in the following embodiments.

Another specific mode in which the vehicle state detecting means measures the roll angle and the roll rate of the traveling vehicle is as follows. The measurement means measures the rotation speed of each wheel of the vehicle, and the roll angle calculation means calculates the sum of the rotation speeds of the left front wheel and the rear wheel from the sum of the rotation speeds of the right front wheel and the rear wheel of the vehicle. The roll angle is calculated by applying the measured rotation speed of each wheel to a physical model that describes the relationship between the turning inner and outer wheel speed difference obtained by subtracting and the roll angle of the vehicle, and the roll rate is calculated by the roll rate calculating means. The calculated roll angle may be differentiated to calculate the roll rate of the vehicle.

By doing so, it is possible to measure the roll angle and roll rate of the traveling vehicle used when calculating the overturn parameter without using a roll rate sensor.

The physical model describing the relationship between the turning inner / outer wheel speed difference and the roll angle will be described in detail in the following embodiments.

Next, in the vehicle behavior control method according to the fourteenth aspect, the vehicle behavior estimation method according to any one of the first to fourth aspects, first comprises, during running of the vehicle, a fall parameter representing the ease of falling of the vehicle. Estimate by method. Then, when the estimated fall parameter is larger than a predetermined value, a braking force is applied to a predetermined wheel to prevent the vehicle from falling.

That is, in the method of the present invention (claim 14), when the fall parameter estimated by the vehicle behavior estimation method according to any one of claims 1 to 4 becomes larger than a predetermined value,
It is determined that there is a high possibility that the vehicle will overturn (roll over), and braking force is applied to predetermined wheels to prevent the vehicle from overturning (rollover).

According to the method of the present invention (claim 14), the vehicle is turned over (overturned) on the basis of the overturning parameter estimated by the vehicle behavior estimation method according to any one of claims 1 to 4. Since control for prevention is performed, it is possible to reliably prevent the vehicle from overturning (rolling over).

That is, according to the vehicle behavior estimating method of any one of claims 1 to 4, as described above, the turning inner wheel (in the case of lane change running, the wheel on the steering direction side) is not lifted. Since it is possible to accurately estimate the possibility of the vehicle overturning (rolling over) at an earlier timing, it is sufficiently early even if, for example, the vehicle performs a lane change running and a turning phenomenon occurs. A braking force can be applied to a predetermined wheel at a timing, and as a result, the vehicle can be reliably prevented from falling (rolling over).

When the overturn parameter is larger than a predetermined value and it is determined that the vehicle is likely to overturn (roll over), a braking force is applied to predetermined wheels to prevent the vehicle from overturning (overturn). As a specific mode, for example, a braking force is applied to the front wheels or front and rear wheels on the turning outer wheel side (in other words, the side opposite to the steering direction) of the vehicle to make the running state of the vehicle understeer, thereby causing the vehicle to fall ( It may be one that prevents rollover).

Further, it is also possible to apply a braking force to both front wheels or all the wheels to reduce the running speed of the vehicle, thereby preventing the vehicle from overturning (rolling over).

On the other hand, the invention according to claim 15 is an invention of a vehicle behavior control device provided with a configuration for realizing the invention method according to claim 14, and firstly, when the vehicle runs, the vehicle falls. A vehicle behavior estimating device according to any one of claims 5 to 13 estimates a fall parameter representing ease of driving. Then, when the estimated fall parameter is larger than a predetermined value, the control means applies a braking force to a predetermined wheel to prevent the vehicle from falling.

According to the present invention (claim 15), claim 5
A vehicle overturn (rollover) based on a overturn parameter estimated by the vehicle behavior estimation device according to any one of claims 13 to 13.
Control to prevent the vehicle from falling (rolling over)
Can be reliably prevented.

In other words, according to the vehicle behavior estimating device of any one of claims 5 to 13, as described above, the turning inner wheel (in the case of lane change running, the wheel on the steering direction side) is not lifted. Since it is possible to accurately estimate the possibility of the vehicle overturning (rolling over) at an earlier timing, it is sufficiently early even if, for example, the vehicle performs a lane change running and a turning phenomenon occurs. A braking force can be applied to a predetermined wheel at a timing, and as a result, the vehicle can be reliably prevented from falling (rolling over).

[0066]

Embodiments of the present invention will be described below with reference to the drawings. Embodiment 1 First, FIG. 1 is a schematic configuration diagram showing an overall configuration of a vehicle behavior control device as one embodiment (embodiment 1) to which the present invention is applied. The vehicle behavior control device according to the present embodiment is applied to a front engine / rear drive (FR) type vehicle.

As shown in FIG. 1, in this vehicle, the driving force (drive torque) of the vehicle output from the internal combustion engine 11 via the transmission 12 is transmitted through the propeller shaft 13 and the differential gear 14 to the left and right rear wheels. (Drive wheels) (the left rear wheel 22RL and the right rear wheel 22RR).

Each of the wheels (front left wheel 22FL, front right wheel 22FR, rear left wheel 22RL, rear right wheel 22RR) of the vehicle is provided with a hydraulic brake device (hereinafter referred to as a wheel) for applying a braking force to the respective wheels 22FL to 22RR. (Also referred to as cylinder) 5
1FL, 51FR, 51RL, and 51RR are provided respectively.

When a brake operation is performed by the driver, each wheel cylinder 51FL is transmitted via the hydraulic circuit 50.
Brake oil is pumped to ~ 51RR, and each wheel 22FL ~
It is configured such that a braking force is applied to 22RR.

The vehicle is provided with a lateral acceleration sensor 41 as a lateral acceleration measuring means according to claim 10, and a detection signal from the lateral acceleration sensor 41 is CP
The data is input to an electronic control unit (ECU) 20 mainly composed of a microcomputer including U, ROM, RAM and the like.

Then, the ECU 20 controls the lateral acceleration sensor 4
In response to the input signal from the controller 1, various actuators provided in the hydraulic circuit 50 are driven separately from the brake operation by the driver, and the respective wheel cylinders 51 FL to 51 R are driven.
By adjusting the brake oil pressure applied to R, the braking force applied to each of the wheels 22FL to 22RR is controlled.

That is, the ECU 20 estimates an overturn parameter indicating the ease of overturning of the vehicle using the input signal from the lateral acceleration sensor 41 during running of the vehicle. Vehicle overturn prevention that appropriately increases the braking force (wheel cylinder pressure) applied to the front wheel on the turning outer wheel side (in other words, the wheel on the side opposite to the steering direction) of the left and right front wheels 22FL and 22FR to prevent the vehicle from rolling over. Execute control and the like.

Next, the hydraulic circuit 50 used for such braking force control will be described.

As shown in FIG. 2, the hydraulic circuit 50
The X pipe is provided with a piping system of a left front wheel 22FL-a right rear wheel 22RR and a right front wheel 22FR-a left rear wheel 22RL.

Of these pipe systems, a pipe 53A1 extending from the master cylinder 52 for pumping brake oil by the driver's operation of the brake pedal 31 to the wheel cylinders 51FL, 51RR of the left front wheel 22FL and the right rear wheel 22RR. The three-way switching valve 54A used for switching the hydraulic circuit (switched to the two positions), the proportion valve 55A for applying a high oil pressure to the wheel cylinder 51FL of the left front wheel 22FL, and the master cylinder 52 to the wheel cylinders 51RR and 51FL Pressure increasing control valves 56 and 57 for controlling the opening and closing of the pipelines, pressure reducing control valves 61 and 62 for controlling the opening and closing of the pipelines from the wheel cylinders 51RR and 51FL to the reservoir 66A, and storing the brake oil from the wheel cylinders 51RR and 51FL. Reservoir 66A, reservoir Master cylinder 52 from over server 66A
A pump 67A for pumping brake oil is provided on the side. A pump 53A2 for increasing the brake oil pressure and a pressurization control for opening and closing a pipe between the master reservoir 69 and the downstream side of the pump 71A are provided in a pipe 53A2 extending from the master reservoir 69 to the three-way switching valve 54A. Valve 72A
Is provided.

When the three-way switching valve 54A is switched to the position A, the brake operation by a normal driver, the pressure increase control valves 56, 57,
Pressure reduction control valves 61 and 62, reservoir 66A, pump 67A
It is possible to perform well-known anti-skid control or the like using the above-described method. On the other hand, when the position is switched to the position B, it is possible to perform the vehicle overturn prevention control by the high brake oil pressure by the pump 71A.

The other pipeline 53B of the piping system from the master cylinder 52 to the wheel cylinders 51FR and 51RL of the right front wheel 22FR and the left rear wheel 22RL.
1 includes a three-way switching valve 54B that can be switched to two positions, and a proportion valve 55, similarly to the pipe 53A1.
B, pressure increasing control valves 58 and 59, pressure reducing control valves 63 and 64, a reservoir 66B, and a pump 67B. Also,
Similarly to the pipe 53A2, a pump 71 is provided in a pipe 53B2 extending from the master reservoir 69 to the three-way switching valve 54B.
B and a pressurization control valve 72B are provided.

The hydraulic circuit 50 includes first and second pressure sensors 75 and 76 for detecting the hydraulic pressure between the three-way switching valves 54A and 54B from the pumps 71A and 71B.
Each three-way switching valve 54A, 54B from the master cylinder 52
And fourth pressure sensors 77 and 78 for detecting the hydraulic pressure during
The detection signals from the sensors 75 to 78 are also input to the ECU 20. And ECU
Reference numeral 20 denotes various actuators based on these detection signals, that is, pressure increase control valves 56 to 59 and pressure decrease control valves 61 to 6.
4. Brake oil pressure applied to each wheel cylinder 51FL-51RR by controlling the pumps 67A, 67B, pumps 71A, 71B, and pressurization control valves 72A, 72B (that is, braking force applied to each wheel 22FL-22RR).
Control.

Next, among the control processes repeatedly executed by the ECU 20 when the vehicle is running (specifically, after an ignition switch (not shown) of the vehicle is turned on), the main processes related to the present invention are described. The vehicle fall prevention control process (vehicle behavior control process) will be described with reference to the flowchart shown in FIG.

As shown in FIG. 3, when the vehicle overturn prevention control process is started, first, S110 (S represents a step).
Reads a detection signal from the lateral acceleration sensor 41.
Then, in S120, the lateral acceleration Gy of the vehicle detected from the input signal from the lateral acceleration sensor 41 is calculated by using the lateral acceleration Gy and the roll angle φ of the vehicle represented by the following equation (1).
_The roll angle φ _O is calculated by applying to a physical model (a Laplace transformed model) describing the relationship with _O.

[0081]

(Equation 1)

(However, K1 and K2: constants) In this embodiment, the detection value from the lateral acceleration sensor 41 is used.
A certain lateral acceleration Gy is positive when turning left (revolution) and turning right.
(Revolution) is output as a negative value at roll time φ _OIs
Positive when the vehicle leans to the right, negative when leaning to the left
Is calculated.

Next, at S130, the roll angle φ _O calculated at S120 is differentiated by applying the roll angle φ _O to the following equation (2) to calculate the roll rate φ _O ′ of the vehicle.

Φ _O ′ = s · φ _O (2) Then, at S140, the maximum amplitude A of the roll angle φ behavior estimation value φ (t) defined by the following equation (6) is estimated. Actual fall (rollover) of the traveling vehicle calculated (measured) in S120 and S130 based on the following arithmetic expression (3)
The estimated value A of the maximum amplitude of the behavior estimated value φ (t) of the roll angle φ is calculated by using the measurement results of the roll angle φ _O and the roll rate φ _O ′ indicating the tendency, and the estimated value A is used as the vehicle falls. It is assumed that the fall parameter X indicates the ease of performing.

[0085]

(Equation 2)

(However, p, w: characteristic values (constants) of the vibration system) In step S140, when calculating the overturning parameter X, the measurement results of the roll angle φ _O and the roll rate φ _O ′ are used as parameters. A map (not shown) in which the relationship between the roll angle φ _O and the roll rate φ _O ′ and the fall parameter X is set in advance is used so that the fall parameter X corresponding to the above equation (3) can be easily calculated. .

Here, at S140, the fall parameter X
The above equation (3) used when obtaining is set as follows.

First, the vehicle behavior during vehicle running (overturning behavior) based on the roll angle φ indicating the tendency of the running vehicle to overturn (roll over).
Is described as in the following equation (4).

Jφ ″ + Dφ ′ + Kφ = F (4) (where J: roll inertia, D: damper constant, K: spring constant, F: centrifugal force, φ ″: roll rate differential value, φ ′:
Roll rate, φ: roll angle) Among the above parameters, the centrifugal force F (see FIG. 9) is
When the lateral acceleration Gy of the vehicle detected from the input signal from the lateral acceleration sensor 41 is used, it is expressed by the following equation (5).

[0090]

(Equation 3)

(W: vehicle weight, h: height of vehicle center of gravity, g: gravitational acceleration) From the above equations (4) and (5), the following equation (6) for estimating the behavior of the roll angle φ is obtained. Can be derived.

[0092]

(Equation 4)

In the above parameters, A is a roll angle φ behavior estimation value φ (t) defined by the above equation (3).
, The maximum amplitude (estimated value), e ^{− (p} · ^{t / 2)} is the damping element, sin
(W · t + θ) is a resonance element, and in this resonance element, the phase angle θ is calculated (measured) in S120 and S130.
This is calculated as a constant corresponding to the measured result of the roll angle φ _O and the roll rate φ _O ′ indicating the actual tendency of the traveling vehicle to overturn (roll over).

Using the above equation (6), the external force acting on the vehicle in the initial state (the state at the time t = 0 when the roll angle is φ _O and the roll rate is measured as φ _O ′) Here, the behavior estimation value φ (t) of the roll angle φ after the lapse of the time t, which is expected under the assumption that the centrifugal force F is constant thereafter, can be calculated.

In the above equation (6), the roll angle φ
Although (t) (behavior estimation value) is expressed as one that causes a damped oscillation, in the present embodiment, in S140, the above equation (3) is used.
The maximum amplitude A (estimated value) of the roll angle φ (t) (behavior estimated value) before attenuation is calculated based on the roll angle φ _O and the roll rate φ _O ′ representing the actual tendency of the traveling vehicle to overturn (roll over). The estimated value A is calculated as a value that increases or decreases stepwise according to the measurement result, and the estimated value A is used as a fall parameter X that indicates the ease with which the vehicle falls.

Therefore, in this embodiment, the falling parameter X
Can be calculated as a value that increases or decreases in a stepwise manner corresponding to the actual behavior of the vehicle (falling behavior), and the fall parameter X is used to accurately estimate the ease of the vehicle falling (rolling over). be able to.

That is, in this embodiment, the fall parameter X
Is calculated as a value that gradually increases or decreases in response to the actual vehicle behavior (falling behavior) from the time before the turning inner wheel (in the case of lane change traveling, the wheel on the steering direction side) floats, In addition, since the overturn parameter X is calculated as a value obtained by constantly estimating the possibility of overturning (overturning) of the traveling vehicle, that is, the possibility of overturning (overturning) is always large (dangerous side), the turning inner wheel (lane change) is performed. In the case of traveling, it is possible to accurately and easily estimate the likelihood of the vehicle falling over at an early timing before the floating of the wheel in the steering direction).

When the fall parameter X is calculated in the processing of S140 as described above, this time, S1
Move to 50.

In S150, it is determined whether or not the braking force applied to the right front wheel 22FR or the left front wheel 22FL is currently increased to prevent the vehicle from overturning (rolling over).

That is, the processing of S180 or S190 until the previous flow of the vehicle overturn prevention control processing (described later).
Accordingly, the braking force applied to the right front wheel 22FR or the left front wheel 22FL is increased, and it is determined whether or not the braking force is still being increased.

Then, in S150, the right front wheel 22 is currently
If it is determined that the braking force applied to the FR or the left front wheel 22FL is not increased, the process proceeds to S160, where the overturn parameter X is a first evaluation coefficient Ka (Ka> 0) that is a predetermined value set in advance. A determination is made whether it is greater than.

In S160, if it is determined that the fall parameter X is larger than the first evaluation coefficient Ka, that is, if it is determined that the vehicle is likely to fall (roll over),
The process proceeds to S170, and it is determined whether the lateral acceleration Gy, which is a detection value from the lateral acceleration sensor 41, is greater than zero.

Then, in S170, the lateral acceleration Gy becomes 0
If it is larger, that is, it is determined to be positive, S1
80, the front wheel on the turning outer wheel side (in the case of lane change running, on the opposite side to the steering direction) is determined to be the right front wheel 22FR, and the running state of the vehicle tends to understeer, and the vehicle falls over (rollover). Prevent (in other words,
By driving various actuators in the hydraulic circuit 50 so as to decrease the overturn parameter X), the braking force applied to the right front wheel 22FR, that is, the brake oil pressure applied to the wheel cylinder 51FR is increased, and the vehicle overturn prevention control process is performed once. To end.

If the result of the determination in S170 is negative, that is, if the lateral acceleration Gy is not greater than 0, that is, if it is determined to be negative, for example, the routine proceeds to S190, where the turning outer wheel side (for lane change running) is executed. In this case, the front wheel on the side opposite to the steering direction) is determined to be the left front wheel 22FL, and the running state of the vehicle tends to understeer, and the vehicle falls (rolls over).
By driving various actuators in the hydraulic circuit 50 to increase the braking force applied to the left front wheel 22FL, that is, the brake oil pressure applied to the wheel cylinder 51FL, so as to prevent (in other words, reduce the overturn parameter X). Then, the vehicle overturn prevention control process is temporarily ended.

On the other hand, if it is determined in S160 that the fall parameter X is not larger than the first evaluation coefficient Ka, there is no possibility that the vehicle will fall (roll over), so that the left and right front wheels 22FL, 22FR It is determined that it is not necessary to increase one of the braking forces, and the vehicle overturn prevention control process is once ended.

On the other hand, if it is determined in S150 that the braking force applied to the right front wheel 22FR or the left front wheel 22FL is currently increased to prevent the vehicle from overturning (rolling over), The flow shifts to S200, where the fall parameter X is set to the second evaluation coefficient Kb which is a predetermined value set in advance.
(However, it is determined whether or not 0 <Kb <Ka).

Then, in S200, the fall parameter X
Is smaller than the second evaluation coefficient Kb, it is determined that there is no longer a possibility that the vehicle will overturn (roll over), and the flow shifts to S210, where the braking force applied to the right front wheel 22FR or the left front wheel 22FL is determined. Is reduced, and the vehicle overturn prevention control process is once ended.

If it is determined in S200 that the overturn parameter X is not smaller than the second evaluation coefficient Kb, it is determined that the possibility that the vehicle will overturn (roll over) still remains. Right front wheel 22FR or Left front wheel 22FL
While the state in which the braking force applied to the vehicle is increased is maintained, the vehicle overturn prevention control process is temporarily terminated.

The processing in S120 corresponds to the roll angle calculating means in claim 10, and the processing in S130 is in claim 10
The processing of S140 is equivalent to the roll rate calculation means of
S150 corresponds to the falling parameter estimating means of claim 6.
To S210 (especially, S160 to S190)
Corresponds to the control means of claim 15.

As described above, in the present embodiment, the physical model represented by the equation (4) describing the vehicle behavior (falling behavior) based on the roll angle φ indicating the tendency of the running vehicle to roll over (roll over). S12 based on the operation formula (3) derived from
0, roll angle φ (t) (behavior estimation value) using the measurement results of roll angle φ _O and roll rate φ _O ′ representing the actual overturning (rollover) tendency of the traveling vehicle calculated (measured) in S130. ) Is calculated before the attenuation (estimated value), and the estimated value A is used as a fall parameter X (S140).

Therefore, in this embodiment, the falling parameter X
Can be calculated as a value that increases or decreases stepwise in accordance with the actual behavior of the vehicle (falling behavior), and the fall parameter X can accurately estimate the ease of the vehicle falling. .

That is, in this embodiment, the fall parameter X
Is calculated as a value that gradually increases or decreases in response to the actual vehicle behavior (falling behavior) from the time before the turning inner wheel (in the case of lane change traveling, the wheel on the steering direction side) floats, In addition, since the overturn parameter X is calculated as a value obtained by constantly estimating the possibility of overturning (overturning) of the traveling vehicle, that is, the possibility of overturning (overturning) is always large (dangerous side), the turning inner wheel (lane change) is performed. In the case of traveling, it is possible to accurately and easily estimate the likelihood of the vehicle falling over at an early timing before the floating of the wheel in the steering direction).

In the present embodiment, the vehicle falls (rolls over) based on the fall parameter X estimated in this way.
Is performed (S150 to S210), it is possible to reliably prevent the vehicle from overturning (rolling over).

That is, in the present embodiment, as described above, the turning inner wheel (in the case of lane change running, the wheel on the steering direction side) surely comes at an early timing before floating.
Since it is possible to accurately estimate the likelihood of the vehicle overturning (rolling over), for example, even if the vehicle undergoes a lane change running and a rolling phenomenon occurs, the predetermined wheels can be set at a sufficiently early timing. (S180, S180)
190), and as a result, it is possible to reliably prevent the vehicle from overturning (rolling over).

In the above embodiment, the roll angle φ _O and the roll rate φ _O ′ used for calculating the overturn parameter X (S140) are calculated (measured) (S120, S130).
Time, first, the lateral acceleration Gy which is a detection value from the lateral acceleration sensor 41 is applied to Equation (1) calculates the roll angle phi _O (Measurement) (S120), further, the roll angle phi _O the formula ( The roll rate φ _O ′ was calculated (measured) by applying to (2) (S130), but a roll rate sensor was provided instead of the lateral acceleration sensor 41, and the roll rate sensor firstly used the roll rate sensor. _O ′, and then the roll rate φ _O ′, which is the value detected from the roll rate sensor.
And represented by the following formula (7), applied to a physical model describing the relationship between the roll rate phi _O 'and the roll angle phi _O of the vehicle (Laplace transformed model), the roll angle phi _O It may be calculated (measured).

[0116]

(Equation 5)

(However, K3 and K4 are constants) The roll rate sensor in this case corresponds to the roll rate measuring means of the ninth aspect.
The calculation (measurement) process of the roll angle φ _O performed in U20 corresponds to the roll angle calculation means in claim 9.

In this embodiment, the front wheels on the turning outer wheel side (in the case of lane change running, on the side opposite to the steering direction) are the left and right front wheels 22FL, 22F.
S performed to determine which of R
The processing corresponding to 170 may be performed by determining whether the roll rate φ _O ′ is greater than 0.

Specifically, when the roll rate φ _O ′ is larger than 0, that is, it is determined to be positive, the turning outer wheel side (for lane change running, the wheel on the opposite side to the steering direction). Can be determined to be the right front wheel 22FR, the process proceeds to S180. Conversely, if the roll rate φ _O ′ is not greater than 0, that is, if it is determined to be negative, for example, Since it can be determined that the front wheel (the wheel on the opposite side to the steering direction in the case of lane change running) is the left front wheel 22FL, S1
The process moves to 90.

When the lateral acceleration sensor 41 is provided in addition to the roll rate sensor in the same manner as in the above embodiment, the processing in S170 can be executed in the same manner as in the above embodiment. (Embodiment 2) Next, Embodiment 2 will be described.

The description of the same parts as in the first embodiment is as follows.
Omitted or simplified.

First, FIG. 4 is a schematic configuration diagram showing an overall configuration of a vehicle behavior control device as one embodiment (Embodiment 2) to which the present invention is applied.

In this embodiment, each wheel 22FL-2FL of the vehicle
2RR is provided with wheel speed sensors 42FL, 42FR, 42RL, 42RR for detecting the rotation speeds of the wheels 22FL to 22RR (hereinafter also referred to as wheel speeds). Instead of the lateral acceleration sensor 41, a yaw rate sensor 43 is provided as a yaw rate measuring means according to the present invention.

Then, the wheel speed sensors 42FL to 42R
The detection signals from the R and yaw rate sensors 43 are input to the ECU 20 together with the detection signals from the brake switch 32. The brake switch 32 is turned on when the brake pedal 31 is depressed, and turns on a stop lamp (not shown).

Next, when the vehicle is running (specifically, after an ignition switch (not shown) of the vehicle is turned on), the ECU 20 repeatedly executes the vehicle overturn prevention control process (vehicle rotation prevention process) in this embodiment. The behavior control process will be described with reference to the flowcharts shown in FIGS.

As shown in FIG. 5, when the vehicle overturn prevention control process is started, first, in S310 corresponding to the process of S110 in the first embodiment, the wheel speed sensors 42FL to 42R
R, yaw rate sensor 43, and brake switch 32
Read the detection signal from. Then, in S320, a vehicle speed estimation process is executed.

The vehicle speed estimation process is a process for estimating (measuring) the vehicle speed Vb _{O of the} vehicle based on the detection signal read in S310, and is executed as shown in FIG.

That is, in the vehicle speed estimation process, first, in S51
At 0, a correction calculation of the wheel speed of each of the wheels 22FL to 22RR is performed. Specifically, wheel speed sensors 42FL-42
Each wheel 22FL-2 detected from the input signal from RR
2RR wheel speeds VWFL _O , VWFR _O , VWRL _O ,
A correction operation for converting VWRR _O into the velocity of the center of gravity of the vehicle is performed using the following equations (8) to (11) using the yaw rate ψ _O ′ of the vehicle detected from the input signal from the yaw rate sensor 43. .

VWFL _O forVb _O = VWFL _O -Lf × ψ _O '(8) VWFR _O forVb _O = VWFR _O -Lf × ψ _O ' (9) VWRL _O forVb _O = VWRL _O -Lr × ψ _O ' (10) VWRR _{O for} Vb _O = VWRR _O -Lr × ｒ _O '(11) Among the parameters in the above equations (8) to (11), VWFL _{O for} Vb _O , VWFR _{O for} Vb _O , VWRL
_O forVb _O and VWRR _O forVb _O are each wheel 22FL
The wheel speed after correction of ２２22 RR is shown. Lf is
Lr indicates the shortest distance from the center of gravity of the vehicle to the front shaft (front drive shaft), and Lr indicates the shortest distance from the center of gravity of the vehicle to the rear shaft (rear drive shaft).
In the present embodiment, the yaw rate ψ _O ′, which is a detection value from the yaw rate sensor 43, is output as a positive value when turning left (rotation) and a negative value when turning right (rotation).

Next, in S520, it is determined whether or not the vehicle is currently decelerating. This determination is made by determining whether or not the input signal from the brake switch 32 is on (ON).

If it is determined in S520 that the vehicle is in a deceleration state, the flow shifts to S530, where the following equation (1) is obtained.
In 2), the vehicle speed Vb _O (estimated value) is calculated.

Vb _O = max (VW ** for Vb _O ) (12) Note that among the parameters in the above equation (12), VW *
* ForVb _O indicates the corrected wheel speed of all wheels calculated by the above equations (8) to (11), and ** indicates the
FL to 22RR are shown. Then, the equation (12), of the wheel speed after the correction of all the wheels, indicating that calculates what is the maximum wheel speed as the vehicle speed Vb _O.

That is, if the vehicle is in a decelerating state, the wheels may slip into deceleration due to, for example, the operation of the brakes on the wheels 22FL to 22RR or the operation of the engine brake on the wheels 22FL to 22RR.
There is a possibility that the wheel speed of the wheel that has fallen into a deceleration slip (corrected wheel speed) may be extremely lower than the vehicle body speed.

Therefore, in S530, of the corrected wheel speeds of all the wheels, the maximum wheel speed corresponding to the corrected wheel speed of the wheel not falling into the deceleration slip (in other words, the wheel gripped on the road surface) is determined. it is to calculate the body speed Vb _O.

On the other hand, if it is determined in S520 that the vehicle is not in a deceleration state, the flow shifts to S540, where the following equation (1) is obtained.
In 3), the vehicle speed Vb _O (estimated value) is calculated.

[0136] _{Vb O = min (VW ** forVb} O) ... (13) the equation (13), of the wheel speed after the correction of all the wheels,
Indicates that calculates what the minimum wheel speed as the vehicle speed Vb _O.

That is, as a case where the vehicle is not in a decelerating state, for example, it can be considered that the vehicle is accelerating. In this case, the wheel speed of the wheel that has slipped into the acceleration slip (corrected wheel speed)
May be significantly higher than the vehicle speed.

In S540, of the corrected wheel speeds of all the wheels, the minimum wheel speed corresponding to the corrected wheel speed of the wheel not falling into the acceleration slip (in other words, the wheel gripped on the road surface) is determined. it is to calculate the body speed Vb _O.

When the vehicle speed Vb _O is calculated in S530 or S540, the process proceeds to S550.

At S550, the change gradient of the vehicle speed Vb _O calculated as described above is limited, and the vehicle speed estimation process is completed.

That is, in S550, S3 in the previous flow is executed.
The vehicle speed calculated at the time of the current flow from the vehicle speed calculated at the time of the previous flow, according to the vehicle longitudinal acceleration Vb _O ′ which is the acceleration in the front-rear axis direction of the vehicle calculated as the estimated value in the process of 30 (described later) By limiting the amount of change to the vehicle speed, the vehicle speed Vb _O calculated in the current flow is corrected.

Thus, the vehicle speed estimation process (S320)
When the vehicle speed Vb _O is estimated (measured), the vehicle longitudinal acceleration estimation process is executed in S330 (see FIG. 5).

This vehicle longitudinal acceleration estimation process is a process of calculating the vehicle longitudinal acceleration Vb _O ′ (estimated value) in the current flow, and is executed as shown in FIG.

That is, in the vehicle body longitudinal acceleration estimation processing, first in S610, the vehicle body speed Vb calculated in the vehicle body speed estimation processing (S320) within a predetermined time up to the current flow.
_O is filtered by a low-pass filter. Specifically, for example, using a low-pass filter that passes only a frequency of 10 Hz or less, the vehicle speed Vb _O as an estimated value is used.
Remove the noise inside.

Next, in S620, the vehicle speed Vb _O filtered in S610 is differentiated.

At S630, the value calculated at S620, that is, the vehicle longitudinal acceleration Vb _O ′ is filtered, and the vehicle longitudinal acceleration estimation processing is completed. Specifically, for example, the vehicle body longitudinal acceleration V calculated in S620
Apply b _O ′ to a low-pass filter that passes only frequencies below 2 Hz.

Thus, the vehicle longitudinal acceleration estimation processing (S3
30), the vehicle longitudinal acceleration Vb in the current flow
_{When O} ′ (estimated value) is calculated, this time, S1 of the first embodiment is calculated.
The process proceeds to S340 (see FIG. 5) corresponding to the process of No. 20.

In S340, the yaw rate ψ _O 'of the vehicle detected from the input signal from the yaw rate sensor 43 and the vehicle speed Vb _O estimated (measured) by the vehicle speed estimation process (S320) are calculated by the following equation (14). ) Is applied to a physical model (Laplace-transformed model) describing the relationship between the yaw rate ψ _O ′ and the vehicle speed Vb _O and the roll angle φ _{O of the} vehicle to calculate the roll angle φ _O. .

[0149]

(Equation 6)

(However, J: roll inertia, D: damper constant, K: spring constant, W: vehicle weight, h: height of vehicle center of gravity,
g: Gravitational acceleration) Next, in S350 corresponding to the processing in S130 of the first embodiment, the roll angle φ _O calculated in S340 is calculated by the equation (2).
Differentiate by applying to the vehicle roll rate φ
Calculate _O '.

Next, in S360 corresponding to the processing in S140 of the first embodiment, S340, S3
The roll angle φ _O and the roll rate φ _O ′, which indicate the actual overturning (rollover) tendency of the traveling vehicle, calculated (measured) at 50.
Using the measurement results of the above, the behavior estimation value φ (t) of the roll angle φ
Is calculated, and the estimated value A is used as a fall parameter X representing the ease of falling of the vehicle.

After the fall parameter X is calculated in the process of S360, the process proceeds to S370.

Here, each processing of S 370 to S 430 is
It corresponds to each processing of S150 to S210 of the first embodiment, respectively.
Except for the process of S390 (corresponding to the process of S170 of the first embodiment), the process is executed substantially in the same manner as the processes of S150 to S210.

The processing in S390 is the same as that in the first embodiment.
Similarly to the processing of step 170, in order to determine which of the left and right front wheels 22FL and 22FR is the front wheel on the turning outer wheel side of the vehicle (in the case of lane change running, the wheel on the opposite side to the steering direction). In the present embodiment, unlike the first embodiment, since the vehicle is not provided with the lateral acceleration sensor 41, in S390, the yaw rate ψ _O ′, which is the detection value from the yaw rate sensor 43, is greater than 0. By determining whether or not the front wheels on the turning outer wheel side of the vehicle (the wheels on the side opposite to the steering direction in the case of lane change driving) are the left and right front wheels 22FL, 22F.
R is determined.

Specifically, when it is determined that the yaw rate ψ _O ′ is larger than 0, that is, it is positive, the front wheels on the turning outer wheel side (in the case of lane change running, on the opposite side to the steering direction) are turned on. Since the right front wheel 22FR can be determined, the process proceeds to S400 (corresponding to the process of S180 of the first embodiment), and conversely, the roll angle φ _O is not larger than 0, that is, it is determined that the roll angle φ _O is negative, for example. In this case, since it can be determined that the front wheel on the turning outer wheel side (in the case of lane change running, on the opposite side to the steering direction) is the left front wheel 22FL, the flow shifts to S410 (corresponding to the processing of S190 in the first embodiment). It is.

The processing of S320 corresponds to the vehicle speed measuring means of the present invention, and the processing of S340 corresponds to the processing of the present invention.
The processing in S350 corresponds to the roll rate calculating means in claim 11, and the processing in S360 is the same as the processing in S140 in the first embodiment. S370 to S430
(Particularly, the processing of S380 to S410) is performed in the first embodiment.
Processing of S150 to S210 (particularly, S160 to S190
Similarly to the above-described process, the control means corresponds to the control means of claim 15.

As described above, in this embodiment, the implementation
As in the case of Example 1, the row indicating the tendency of the running vehicle to fall (roll over)
Formula describing vehicle behavior (overturning behavior) based on angle φ
Operation formula derived from the physical model represented by (4)
Calculated (measured) in S340 and S350 based on (3)
Roll indicating the actual tendency of the driven vehicle to overturn (roll over)
Angle φ _OAnd roll rate φ_O'Using the measurement result of
The maximum amplitude A (estimated) of the angle φ (t) (behavior estimation value) before attenuation
Constant value), and the estimated value A is defined as a fall parameter X.
(S360).

Therefore, in this embodiment, as in the first embodiment, the fall parameter X can be calculated as a value that increases or decreases stepwise in accordance with the actual vehicle behavior (fall behavior). With the parameter X, it is possible to accurately estimate the possibility of the vehicle falling over.

In other words, in the present embodiment, as in the first embodiment, the overturn parameter X is set such that the turning inner wheel (in the case of lane change running, the wheel on the steering direction side) starts moving from the time before the actual vehicle is lifted. The falling parameter X is calculated as a value that increases and decreases in a stepwise manner in accordance with the behavior (falling behavior), and the falling parameter X indicates the ease with which the traveling vehicle falls (overturns),
That is, since the possibility of overturn (rollover) is calculated as a value that is always estimated to be relatively large (dangerous side), it is ensured that the timing immediately before the turning inner wheel (the wheel on the steering direction side in the case of lane change driving) floats. Thus, it is possible to accurately estimate the ease of falling of the vehicle.

Then, in the present embodiment, based on the fall parameter X estimated in S360, similar to the first embodiment,
Control is performed to prevent the vehicle from overturning (rolling over) (S3)
70 to S430), it is possible to reliably prevent the vehicle from overturning (rolling over).

That is, in the present embodiment, as in the case of the first embodiment, the vehicle falls over accurately (at an early timing) before the turning inner wheel (in the case of lane change running, the wheel on the steering direction side) floats. Since it is possible to estimate the ease of rolling over, for example, even when the vehicle performs lane change running and a rolling phenomenon occurs, braking force is applied to predetermined wheels at sufficiently early timing ( S40
0, S410), and as a result, it is possible to reliably prevent the vehicle from overturning (rolling over).

In the above embodiment (Embodiment 2), the wheel speed VWFL _O is used in the vehicle speed estimation process (S320).
～VWRR _O to be converted into the speed of position of center of gravity of the vehicle (S5
10) At the time, equations (8) to (10) using the yaw rate ψ _O 'of the vehicle are used.
(11) is used, but if the vehicle is also provided with the lateral acceleration sensor 41, the yaw rate ψ _O ′ in Expressions (8) to (11) is set to the lateral acceleration detected from the input signal from the lateral acceleration sensor 41. Conversion value by the following equation (15) using Gy:
_O 'may be calculated as H.

Ψ _O 'H = Gy / Vb _(n-1) (15) In the above equation (15), Vb _(n-1) is the vehicle speed Vb _O calculated in the previous flow. . Further, in the mode using the above equation (15), when the vehicle is traveling at an extremely low speed (for example, traveling at an extremely low speed of 5 km / h or less, which is equal to or less than the resolution limit of the wheel speed sensors 42FL to 42RR). ), Vb in the above equation (15)
_In order not to perform the operation with _{(n-1) set} to 0, Vb
ψ _O 'H may be calculated by substituting a fixed value (for example, 5 km / h) for _(n-1) .

In the above embodiment (Embodiment 2), in the vehicle speed estimation process (S320), when it is determined whether or not the vehicle is in a deceleration state (S520), an input signal from the brake switch 32 is determined. Although the determination is made using the above, for example, one of the following three aspects (to) may be adopted. Further, a mode in which at least two of the following three modes (-) and the modes of the above-described embodiment (that is, modes using an input signal from the brake switch 32) may be adopted.

Body longitudinal acceleration estimation processing (S330)
Longitudinal acceleration Vb calculated by _O'(In the previous flow
The calculated value) is positive or negative.
It is determined whether or not is in a deceleration state.

ECU 20 detects an IDL (idle) signal (for example, a signal whose output changes depending on whether an accelerator pedal (not shown) is depressed) to determine whether the vehicle is in a deceleration state. to decide.

A state in which a master cylinder pressure sensor for detecting the pressure in the master cylinder 52 is provided, and a value detected by the master cylinder pressure sensor (pressure) is equal to or higher than a reference value, and a wheel braking force is substantially generated. By determining whether or not the vehicle is decelerating, it is determined whether or not the vehicle is in a deceleration state.
Note that, for example, at least one of the third and fourth pressure sensors 77 and 78 (see FIG. 2) can function as the master cylinder pressure sensor.

On the other hand, the measurement (estimation) processing of the vehicle body speed Vb _O (corresponding to the vehicle body speed measuring means of claim 11) includes the following driven wheels (the first and second embodiments). As described above, in the case of a front engine / rear drive type vehicle, the average value of the rotation speeds of the left and right driven wheels (average driven wheel speed) obtained from the wheel speed sensors that detect the wheel speeds of the front wheels 22FL and 22FR is calculated as the vehicle speed. It may be detected as Vb _O (estimated value).

In the above embodiment (Embodiment 2), the roll angle φ used to calculate the overturn parameter X (S360) is determined.
Calculate (measure) _O and roll rate φ _O ′ (S34)
0, S350), first, the yaw rate ψ _O ′ detected by the yaw rate sensor 43 and the vehicle speed estimation processing (S
Calculating a roll angle phi _O by applying the vehicle speed Vb _O estimated (measured) by 320) into equation (14) (measurement) to (S340), further, the roll angle phi _O in formula (2) The roll rate φ _O ′ was calculated (measured) by applying (S35)
0) is a vehicle provided with a steering angle sensor, first, the steering angle sensor measures the steering angle δ _O of the vehicle, and the above-described embodiment (embodiment 2).
The vehicle body speed Vb _O is estimated (measured) in the same manner as described above, and the steering angle δ _O
And the vehicle speed Vb _O are represented by the following equation (16):
The roll angle φ _O is calculated (measured) by applying to a physical model (a Laplace-transformed model) describing the relationship between the steering angle δ _O and the vehicle speed Vb _O and the roll angle φ _{O of the} vehicle,

[0170]

(Equation 7)

[0171] (where, K5, K6, K7: constants) Then, the roll rate phi _O 'may be calculated (measured) was applied to the equation (2) the roll angle phi _O.

The steering angle sensor in this case is described in claim 1
Embodiment 2 corresponds to the steering angle measuring means of the second embodiment.
The process of estimating (measuring) the vehicle body speed Vb _{O in the same} manner as the above corresponds to the vehicle body speed measuring means of the twelfth aspect.
Calculating (measuring) the processing of the roll angle phi _O performed by the ECU20 using corresponds to the roll angle calculating unit in claims 12, roll rate phi _O by applying the roll angle phi _O in formula (2) The process of calculating (measuring) 'corresponds to the roll rate calculating means of claim 12.

Further, in this embodiment, the steering angle δ _O, which is a detection value from the steering angle sensor, is output as a positive value during left steering and a negative value during right steering.

In this embodiment, the front wheels on the turning outer wheel side of the vehicle (the wheels on the side opposite to the steering direction in the case of lane change running) are the left and right front wheels 22FL,
The process corresponding to S390 performed to determine which of the 22FR is performed may be performed by determining whether the steering angle δ _O is greater than 0.

Specifically, when the steering angle δ _O is larger than 0,
That is, when it is determined that the front wheel is right, the front wheel on the turning outer wheel side (in the case of lane change traveling, the wheel on the opposite side to the steering direction) can be determined to be the right front wheel 22FR, and the process proceeds to S400. Conversely, if the steering angle δ _O is not larger than 0, that is, if it is determined to be negative, for example, the front wheels on the turning outer wheel side (in the case of lane change traveling, the wheels on the opposite side to the steering direction). Is the front left wheel 2
Since it can be determined that it is 2FL, the process shifts to S410.

As described above, the processing corresponding to S390 is performed by using the steering angle δ _O , and further, the measurement (estimation) processing of the vehicle body speed Vb _O (the vehicle body speed measuring means of claim 12) If the average driven wheel speed is measured as the vehicle speed Vb _O , the overturn parameter X is calculated in the same manner as in the above embodiment (Embodiment 2) without using the yaw rate sensor 43. It is also possible to reliably prevent the vehicle from overturning (rolling over).

That is, even if the yaw rate sensor 43 is omitted, in the case of a vehicle of a front engine / rear drive system as in the above-described embodiment (the first and second embodiments), the front wheels 25FL which are driven wheels are used. , 25FR), the roll angle φ _{O of} the traveling vehicle used in calculating the overturn parameter X by using only the detection values from the wheel speed sensors 42FL, 42FR provided respectively in the vehicle and the steering angle sensor.
And roll rate φ _O ′ can be calculated (measured),
It is possible to reliably prevent the vehicle from overturning (rolling over).

On the other hand, it is used when calculating the overturn parameter X using only the wheel speeds VWFL _{O to} VWRR _O which are the detection values from the wheel speed sensors 42FL to 42RR provided for the respective wheels 22FL to 22RR. (Measurement) of roll angle φ _O and roll rate φ _O 'of running vehicle
It is also possible.

That is, first, the wheel speed sensors 42FL-
At 42RR, the wheel speed V of each wheel 22FL to 22RR
WFL _O -VWRR _O are measured, and the wheel speed VWFL _O-
The VWRR _O, and turning the outer wheel speed difference pT defined by the following equation (17), describing the relationship between the roll angle phi _O of the vehicle, a physical model (Laplace transform represented by the following formula (18) The roll angle φ _O is calculated (measured) by applying the above-described model.

PT = (VWFR _O + VWRR _O ) − (VWFL _O + VWRL _O ) (17)

[0181]

(Equation 8)

(However, K8 and K9: constants) Then, the roll angle φ _O ′ is calculated (measured) by applying the roll angle φ _O to the equation (2).

In this case, the wheel speed sensors 42FL to 42FL
42RR corresponds to the wheel speed measuring means of claim 13;
Roll performed by ECU 20 using the above equation (18)
Angle φ _OThe calculation (measurement) processing of the roll angle calculation according to claim 13
Roll angle φ_OIs applied to equation (2)
Roll rate φ_O'Is calculated (measured).
3 corresponds to a roll rate calculating means.

In this embodiment, the front wheels on the turning outer wheel side of the vehicle (the wheels on the side opposite to the steering direction in the case of lane change driving) are the left and right front wheels 22FL,
The process corresponding to S390, which is performed to determine which one of the speeds is 22FR, is referred to as a turning inner / outer wheel speed difference pT.
May be determined by determining whether or not is greater than 0.

Specifically, when it is determined that the turning inner / outer wheel speed difference pT is larger than 0, that is, positive, the turning outer wheel side (in the case of lane change running, the wheel on the opposite side to the steering direction is used). ) Can be determined to be the right front wheel 22FR, the process proceeds to S400, and conversely, the turning inner / outer wheel speed difference pT is not larger than 0, ie, for example,
If it is determined to be negative, it can be determined that the front wheel on the turning outer wheel side (in the case of lane change traveling, the wheel on the opposite side to the steering direction) is the left front wheel 22FL, and the process proceeds to S410. It is.

Thus, even if the yaw rate sensor 43 is omitted, the wheel speed sensors 42FL to 42R
If only the detected value from R is used, the roll angle φ _O and the roll rate φ _O ′ of the traveling vehicle used when calculating the overturn parameter X can be calculated (measured), and the vehicle falls (overturn). Can also be reliably prevented.

The embodiments of the present invention have been described above. However, the present invention is not limited to the above-described embodiments (Examples 1 and 2), and various modes can be adopted.

For example, in the above-described embodiments (Embodiments 1 and 2), the case where the present invention is applied to a front engine / rear drive (FR) type vehicle (in other words, a rear wheel drive vehicle) has been described. However, even when the present invention is applied to a front engine / front drive (FF) type vehicle (in other words, a front wheel drive vehicle), the same effects as those of the above-described embodiments (Embodiments 1 and 2) are obtained. be able to.

The above embodiments (Embodiments 1 and 2)
In the above, the maximum amplitude A (estimated value) of the roll angle φ (t) (estimated value) before attenuation is calculated as the overturn parameter X based on the equation (3). For estimating the behavior of the roll angle φ, which is derived from a physical model (that is, a physical model represented by equation (4)) describing the vehicle behavior (overturning behavior) when the vehicle is running based on the roll angle φ indicating the tendency. The arithmetic expression is an arithmetic expression for calculating the overturning parameter X, and a behavior estimation value φ (t) of the roll angle φ after a lapse of time t is calculated based on the arithmetic expression.
(T) may be used as the fall parameter X.

In this case, the arithmetic expression for estimating the behavior of the roll angle φ is represented by the expression (6) as described above using the lateral acceleration Gy which is the detection value from the lateral acceleration sensor 41. In a mode in which the vehicle is provided with the lateral acceleration sensor 41 as in the first embodiment, the overturn parameter X may be calculated based on the equation (6).

An arithmetic expression for estimating the behavior of the roll angle φ is represented by the following expression (19) using the roll rate φ _O ′ detected by the roll rate sensor.
In the embodiment in which the lateral acceleration sensor 41 is removed from the vehicle (that is, the vehicle provided with the lateral acceleration sensor 41) in the first embodiment and the roll rate sensor is provided instead, the falling parameter X is calculated based on the equation (19). May be calculated. The roll angle φ _O in the following equation (19) is calculated by applying a roll rate φ _O ′, which is a detection value from a roll rate sensor, to the equation (7).

[0192]

(Equation 9)

Further, the arithmetic expression for estimating the behavior of the roll angle φ is estimated by the yaw rate ψ _O ′ detected by the yaw rate sensor 43 and the vehicle speed estimation processing (corresponding to the vehicle speed measuring means of claim 11). (Measured) body speed Vb
_{If O} is used, it is expressed by the following equation (20). For example, in the embodiment in which the yaw rate sensor 43 and the wheel speed sensors 42FL to 42RR are provided in the vehicle as in the second embodiment,
The fall parameter X may be calculated based on the equation (20).

[0194]

(Equation 10)

The arithmetic expression for estimating the behavior of the roll angle φ is estimated by a steering angle δ _O , which is a detection value from a steering angle sensor, and a vehicle speed estimation process (corresponding to a vehicle speed measuring means of claim 12). If the (measured) vehicle speed Vb _O is used, the vehicle speed is represented by the following equation (21). For example, the vehicle in the second embodiment (that is, the vehicle provided with the yaw rate sensor 43 and the wheel speed sensors 42FL to 42RR) In the embodiment in which the yaw rate sensor 43 is removed from the above and a steering angle sensor is provided instead, the overturn parameter X may be calculated based on the equation (21).

[0196]

[Equation 11]

The equation for estimating the behavior of the roll angle φ is obtained by using the wheel speeds VWFL _{O to} VWRR _O which are the detection values from the wheel speed sensors 42FL to 42RR.
Using the turning inner / outer wheel speed difference pT calculated by the following formula (22), for example, the vehicle (that is, the yaw rate sensor 43 and the wheel speed sensor 42F in the second embodiment)
In a mode in which the yaw rate sensor 43 is excluded from the vehicle provided with L to 42RR), based on the equation (22),
The fall parameter X may be calculated.

[0198]

(Equation 12)

Then, the above arithmetic expressions (6) and (19)-
A fall parameter X based on one of (22)
As a specific mode of calculating (that is, φ (t)), for example, when controlling the vehicle behavior (that is, S150 to S210 or S370 to S430 for performing control for preventing the vehicle from overturning (rolling over)) A predetermined time t _O (for example, t _O = 0.2 se) in consideration of a control delay in performing the corresponding processing.
c) the estimated value of the roll angle phi of after phi a (t _O), the arithmetic expression (6), (19) is calculated based on any of the - (22), the estimated value phi (t _O ) Is the parameter X
May be used.

That is, when the control for actually preventing the vehicle from overturning (rolling over) is performed based on the overturning parameter X (ie, φ (t _O )) calculated as described above, for example, Using the parameter X, S160 or S38
In the process corresponding to 0, after it is determined that the possibility of the vehicle falling over (rolling over) is high, various actuators in the hydraulic circuit 50 are driven, and the predetermined wheels (the right front wheel 22FR or the left front wheel 22FL) are driven. by braking force applied is increased effectively, because only the control delay occurs a predetermined time t _O to the control system, previously, the estimated value of the roll angle phi after a predetermined time period t _O elapsed considering this control delay phi ( t _O ) is calculated as a fall parameter X.

In this manner, when the vehicle behavior is actually controlled, that is, at a predetermined wheel (the right front wheel 22F).
The estimated value φ (t _O ) of the roll angle φ at the time when the braking force applied to R or the left front wheel 22FL is effectively increased can be calculated as the overturning parameter X, and the turning inner wheel (in the case of lane change running, It is possible to accurately estimate the possibility of the vehicle overturning (rolling over) accurately at an early timing before the wheel on the steering direction side is lifted.

If the vehicle overturn prevention control (vehicle behavior control) is performed based on the overturning parameter X calculated as described above, an appropriate vehicle overturn prevention control corresponding to the actual vehicle behavior (overturn behavior) at the time of control is performed. Control (vehicle behavior control) can be performed.

As described above, the above arithmetic expressions (6) and (1)
Based on any one of 9) to (22), an estimated value φ (t _O ) of the roll angle φ after a lapse of a predetermined time t _O in consideration of a control delay in controlling the vehicle behavior is calculated, and this estimation is performed. Value φ
The process of setting (t _O ) to the fall parameter X corresponds to a fall parameter estimating means in claim 7.

On the other hand, the above equations (6) and (19)
To overturn parameter based on one of (22)
As another specific mode for calculating X (that is, φ (t)),
Is, for example, that the estimated value φ (t) of the roll angle φ is
The time t until the next maximum _xRoll angle after passage
The estimated value of φ (t_x) Is calculated by the above equations (6) and (19).
To (22).
Constant value φ (t_x) Is a fall parameter X,
Is also good.

That is, the above arithmetic expressions (6) and (19)-
As is clear from (22), the behavior estimation value φ (t) of the roll angle φ is expressed as a damped oscillation, and therefore the resonance element sin (w · t + θ) of the behavior estimation value φ (t) is obtained.
Time t _x until but the next 1 or -1, that is, since the calculated estimated value of the roll angle phi after the smallest time t elapsed satisfies the following equation (23) phi a (t _x) as the overturn parameter X is there.

[0206]

(Equation 13)

(However, n is an integer equal to or greater than 0) Then, in this manner, the overturn parameter X (ie,
φ (t)) is calculated as a value obtained by always estimating the possibility of falling (rollover) of the traveling vehicle, that is, the possibility of falling (rollover) to the maximum (dangerous side). In the case of (1), it is possible to accurately and easily estimate the possibility of the vehicle overturning (rolling over) at an early timing before the wheel (the wheel in the steering direction) floats.

As described above, the above arithmetic expressions (6) and (1)
9) Based on any of (22) to (22)
Until the behavior estimation value φ (t) of the roll angle φ becomes the next maximum
Time t_xEstimated value of roll angle φ after elapse (φ (t)_x)
Is calculated, and the estimated value φ (t _x) With the fall parameter X
Is equivalent to the overturning parameter estimating means of claim 8.
I do.

As described above, when calculating the estimated value φ (t _O ) or φ (t _x ) of the roll angle φ as the overturning parameter X, it is determined whether or not the vehicle is highly likely to overturn (roll over). S160 or S380 performed to judge
As a specific mode of the processing corresponding to the above, for example, the above-mentioned estimated value φ (t _O ) or φ (t _x ) which is the fall parameter X
Is determined by determining whether or not the absolute value of is larger than a first evaluation coefficient Ka ′ set in advance corresponding to the fall parameter X in this case.

Further, as a specific mode of the processing corresponding to S200 or S420 performed to determine whether or not the possibility of the vehicle falling over (rolling over) is eliminated, for example, the above estimated value which is the falling parameter X is used. The absolute value of φ (t _O ) or φ (t _x ) is the falling parameter X in this case.
Is determined by judging whether or not the second evaluation coefficient Kb ′ is smaller than a second evaluation coefficient Kb ′ set in advance.

On the other hand, in the processing corresponding to S160 or S380, the fall parameter X is set to the first evaluation coefficient Ka.
(Or Ka '), that is, when it is determined that the vehicle is highly likely to fall (roll over), a braking force is applied to predetermined wheels to prevent the vehicle from falling (roll over). Are the same as those in the above embodiments (Examples 1 and 2)
The braking force is not limited to the one that applies the braking force to the front wheels on the turning outer wheel side (in other words, the side opposite to the steering direction) of the vehicle, but the front and rear sides on the turning outer wheel side (in other words, the side opposite to the steering direction). A braking force may be applied to the wheels.

[0212] Further, it is also possible to apply a braking force to both front wheels or all the wheels to reduce the running speed (vehicle speed) of the vehicle, thereby preventing the vehicle from tipping over (rolling over).

Next, an experimental example supporting the effects of the above-described embodiments (Examples 1 and 2) will be described. [Experimental Example] In this experiment, when an experimental vehicle equipped with a vehicle behavior control device similar to that of the second embodiment and equipped with a steering angle sensor (not shown) is driven to change lanes, an arithmetic expression ( Based on the overturning parameter X calculated based on 3), it was verified whether or not it is possible to reliably prevent the overturning (rollover) of the experimental vehicle.

The result of this experiment will be described with reference to FIG.

FIG. 8 shows that the above-mentioned test vehicle runs in a lane change.
Each detected value (calculated value) in the case of performing a row,
-Rate ψ_O', Body speed Vb_O, Steering angle δ_O, Rollley
Gφ _O', Fall parameter X, and left front wheel 22FL
Braking force (the brake applied to the wheel cylinder 51FL)
This is the oil pressure, which is indicated as “Pfr (oil pressure)” in the figure.
Of the output value) over time.

From FIG. 8, it is found that the test vehicle can be accurately turned over at the early timing before the wheel in the steering direction is lifted by using the overturn parameter X calculated based on the arithmetic expression (3). The easiness can be estimated, and it has been found that the fall (rollover) of the experimental vehicle can be reliably prevented based on the fall parameter X.

That is, first, in FIG. 8, the steering angle δ _O is
The vehicle once increased in the positive direction and then increased in the negative direction, indicating that the test vehicle performed a lane change run to the left.

On the other hand, during this lane change running, the roll rate φ _O ′ greatly fluctuated from positive to negative, and in this experimental vehicle, a rolling phenomenon occurred at the same timing as the steering steering timing. You can see that.

Then, when the steering angle δ _O increases in the negative direction and the roll rate φ _O ′ increases in the negative direction similarly to the steering angle δ _O , that is, when the wheels on the steering steering direction side of this experimental vehicle are used. At a time t1 before the right wheel is lifted.
It can be seen that the fall parameter X has become larger than the first evaluation coefficient Ka. This is because the fall parameter X is calculated as a value that increases and decreases stepwise in response to the actual behavior (fall behavior) of the experimental vehicle from the time before the wheels in the steering direction are lifted. Parameter X
Is calculated as a value obtained by always estimating the likelihood of falling (rolling over) of the traveling vehicle (experimental vehicle), that is, the possibility of overturning (rollover) is always large (dangerous side). This shows that it is possible to accurately estimate the ease of falling of the experimental vehicle at an early timing before the wheels in the steering direction are lifted.

The ECU 20 in this experimental vehicle
Then, at time t1 when the fall parameter X becomes larger than the first evaluation coefficient Ka, it is determined that there is a high possibility that the experimental vehicle will fall (roll over) (in other words, the control flag is set to the ON state), and this experiment is performed. It can be seen that the braking force applied to the front wheel (left front wheel 22FL) on the side opposite to the steering direction of the vehicle has been increased.

That is, due to the control delay of the control system of the vehicle behavior control device in the experimental vehicle, the braking force (Pfr (oil pressure)) applied to the left front wheel 22FL after 0.2 to 0.3 seconds from the time point t1. effectively increased, as a result, the yaw rate [psi _O was increased in the negative direction 'and the roll rate phi _O' is greatly varied in a direction to be 0, it is understood that the overturn parameter X was also greatly reduced.

Thereafter, the ECU 20 determines the time t when the fall parameter X becomes smaller than the second evaluation coefficient Kb.
2, that is, at time t2 when the yaw rate ψ _O ′ and the roll rate φ _O ′ have sufficiently changed to become 0, it is determined that the possibility that the experimental vehicle has overturned (rolled over) has disappeared (in other words, the control flag Is turned off), and the front wheel (left front wheel 22FL) on the opposite side of the steering direction of the experimental vehicle.
It can be seen that the braking force applied to the vehicle has been reduced.

This is because if control for preventing the test vehicle from overturning (rolling over) is performed based on the overturning parameter X calculated based on the arithmetic expression (3), the experimental vehicle can perform lane change traveling. This shows that even if the rolling phenomenon occurs, the test vehicle can be reliably prevented from overturning (rolling over).

Therefore, from the experimental results shown in FIG. 8, the fall parameter X calculated based on the arithmetic expression (3)
It is possible to accurately estimate the ease of the fall of the experimental vehicle at an early timing before the wheels in the steering direction are lifted, and to reliably turn over (roll over) the experimental vehicle based on the overturn parameter X. It was confirmed that it could be prevented.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram illustrating an overall configuration of a vehicle behavior control device according to a first embodiment.

FIG. 2 is an explanatory diagram illustrating a configuration of a hydraulic circuit according to a first embodiment and a second embodiment.

FIG. 3 is a flowchart illustrating a vehicle overturn prevention control process executed by an electronic control unit (ECU) according to the first embodiment.

FIG. 4 is a schematic configuration diagram illustrating an overall configuration of a vehicle behavior control device according to a second embodiment.

FIG. 5 is a flowchart illustrating a vehicle overturn prevention control process executed by an electronic control unit (ECU) according to a second embodiment.

FIG. 6 is a flowchart illustrating a vehicle speed estimation process executed in S320 of FIG. 5;

FIG. 7 is a flowchart illustrating a vehicle longitudinal acceleration estimation process performed in S330 of FIG. 5;

FIG. 8 is a graph showing a detection result according to an experimental example.

FIG. 9 is an explanatory diagram illustrating a vehicle behavior during a turning travel, particularly during a lane change travel.

[Explanation of symbols]

20: electronic control unit (ECU), 32: brake switch, 41: lateral acceleration sensor, 42FL, 42FR, 42
RL, 42RR: Wheel speed sensor, 43: Yaw rate sensor, 50: Hydraulic circuit, 51FL, 51FR, 51R
L, 51RR ... wheel cylinder, 54A, 54B ... 3
Direction switching valves, 56, 57, 58, 59 ... pressure increase control valves, 6
1, 62, 63, 64 ... pressure reducing control valve, 67A, 67B,
71A, 71B ... pump, 72A, 72B ... pressurization control valve, 77 ... third pressure sensor, 78 ... fourth pressure sensor.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification code FI Theme coat ゛ (Reference) B60T 8/58 B60T 8/58 Z G01P 3/56 G01P 3/56 Z // G01C 19/00 G01C 19 / 00 Z F term (reference) 2F105 AA02 BB17 3D037 FA23 FA25 FA26 FB01 3D045 BB40 CC01 EE21 GG00 GG10 GG25 GG26 GG28 3D046 BB21 HH08 HH21 HH23 HH25 HH28 KK06 KK07 LL23 LL37 LL50

Claims (15)

[Claims] 1. A vehicle behavior estimating method for estimating a fall parameter representing the ease of falling of a vehicle during running of the vehicle, comprising: measuring a roll angle and a roll rate of the vehicle; The following physical model describing the vehicle behavior during running: Jφ ″ + Dφ ′ + Kφ = F (where J: roll inertia, D: damper constant, K: spring constant, F: centrifugal force, φ ″: roll rate differential) Value, φ ':
A method for estimating a vehicle behavior, comprising: calculating an estimated value of the overturn parameter using a measurement result of the roll angle and the roll rate based on an arithmetic expression derived from a roll rate (φ: roll angle). 2. The arithmetic expression is an arithmetic expression for estimating the maximum amplitude of the roll angle, and calculates an estimated value of the maximum amplitude of the roll angle based on the arithmetic expression, and converts the estimated value to the overturn. The vehicle behavior estimation method according to claim 1, wherein the method is a parameter. 3. The operation formula for estimating the behavior of the roll angle, based on the operation expression, the roll angle after a lapse of a predetermined time in consideration of a control delay in controlling a vehicle behavior. The vehicle behavior estimation method according to claim 1, wherein an estimated value of the vehicle behavior is calculated, and the estimated value is used as the overturn parameter. 4. The arithmetic expression is an arithmetic expression for estimating the behavior of the roll angle, and calculates an estimated value of the roll angle at the next maximum based on the arithmetic expression. The vehicle behavior estimating method according to claim 1, wherein? 5. A vehicle behavior estimating device for estimating a fall parameter representing the ease of falling of a vehicle during running of the vehicle, a vehicle state detecting means for measuring a roll angle and a roll rate of the vehicle, The following physical model describing vehicle behavior during vehicle travel based on the roll angle Jφ ″ + Dφ ′ + Kφ = F (where J: roll inertia, D: damper constant, K: spring constant, F: centrifugal force, φ ′) ': Roll rate differential value, φ':
A roll parameter estimating means for calculating an estimated value of the overturn parameter using the roll angle and the roll rate measured by the vehicle state detecting means, based on an arithmetic expression derived from the roll rate and the roll angle. A vehicle behavior estimating device comprising: 6. An arithmetic expression for estimating the maximum amplitude of the roll angle, wherein the overturn parameter estimating means calculates an estimated value of the maximum amplitude of the roll angle based on the arithmetic expression. The vehicle behavior estimation device according to claim 5, wherein the estimated value is used as the overturn parameter. 7. The arithmetic expression for estimating the behavior of the roll angle, wherein the overturning parameter estimating means determines a predetermined value in consideration of a control delay in controlling a vehicle behavior based on the arithmetic expression. The vehicle behavior estimation device according to claim 5, wherein an estimated value of the roll angle after a lapse of time is calculated, and the estimated value is used as the overturn parameter. 8. The roll-up angle estimating means, wherein the roll-up angle estimating means calculates the roll angle at the next maximum based on the roll-up angle. The vehicle behavior estimating apparatus according to claim 5, wherein the estimated value is used as the overturn parameter. 9. The vehicle state detecting means includes: a roll rate measuring means for measuring a roll rate of the vehicle; and a roll rate and a roll of the vehicle based on the roll rate measured by the roll rate measuring means. The vehicle behavior estimation device according to any one of claims 5 to 8, further comprising: a roll angle calculation unit configured to calculate the roll angle using a physical model describing a relationship with an angle. 10. The vehicle state detecting means, a lateral acceleration measuring means for measuring a lateral acceleration of the vehicle, and a roll of the vehicle based on the lateral acceleration measured by the lateral acceleration measuring means. A roll angle calculating unit that calculates the roll angle using a physical model describing a relationship with an angle; and calculating a roll rate of the vehicle by differentiating the roll angle calculated by the roll angle calculating unit. The vehicle behavior estimation device according to any one of claims 5 to 8, further comprising: a roll rate calculation unit. 11. A vehicle state detecting means, comprising: a yaw rate measuring means for measuring a yaw rate of the vehicle; a vehicle body speed measuring means for measuring a vehicle body speed of the vehicle; A roll angle calculating means for calculating the roll angle using a physical model describing a relationship between the yaw rate and the vehicle speed and the roll angle of the vehicle; and differentiating the roll angle calculated by the roll angle calculating means. The vehicle behavior estimating device according to any one of claims 5 to 8, further comprising: a roll rate calculating unit configured to calculate a roll rate of the vehicle by: 12. The vehicle state detecting means, a steering angle measuring means for measuring a steering angle of the vehicle, a vehicle speed measuring means for measuring a vehicle speed of the vehicle, and a measurement result of the steering angle and the vehicle speed. A roll angle calculating means for calculating the roll angle using a physical model describing a relationship between the steering angle, the vehicle speed and the roll angle of the vehicle, based on the steering angle and the vehicle speed; and the roll angle calculated by the roll angle calculating means. The vehicle behavior estimating device according to any one of claims 5 to 8, further comprising: a roll rate calculating unit configured to calculate a roll rate of the vehicle by differentiating the vehicle speed. 13. The vehicle state detection means, comprising: a wheel speed measurement means for measuring a rotation speed of each wheel of the vehicle; and a rotation speed of each wheel measured by the wheel speed measurement means, A physical model describing the relationship between the turning inner and outer wheel speed difference obtained by subtracting the sum of the rotational speeds of the left front wheel and rear wheel from the sum of the rotational speeds of the right front wheel and rear wheel of the vehicle and the roll angle of the vehicle. A roll angle calculating unit that calculates the roll angle by using the roll angle calculating unit, and a roll rate calculating unit that calculates a roll rate of the vehicle by differentiating the roll angle calculated by the roll angle calculating unit. The vehicle behavior estimation device according to any one of claims 5 to 8, wherein: 14. A vehicle behavior estimating method according to any one of claims 1 to 4, wherein when the vehicle is running, an overturn parameter representing the ease of overturning of the vehicle is estimated. A vehicle behavior control method comprising: applying a braking force to a predetermined wheel to prevent the vehicle from overturning when the vehicle is large. 15. The vehicle behavior estimating device according to claim 5, which estimates a fall parameter representing the likelihood of falling of the vehicle during running of the vehicle, and wherein the fall parameter is larger than a predetermined value. And a control means for applying a braking force to a predetermined wheel to prevent the vehicle from tipping over.