JP2943566B2 - Method for judging vehicle limit state and panic state - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of judging a limit state of a vehicle in which the vehicle enters a limit state in which the vehicle responds non-linearly to steering, and a panic caused by excessive steering in the limit state. The present invention relates to a panic state determination method for determining entry into a state.

[0002]

2. Description of the Related Art In order to make it possible for a driver to make a turn intended by a driver, it is also possible to prevent fluctuations in the course of the vehicle even in the event of disturbance such as crosswinds or uneven road surfaces. The performance is improved. For this reason, the performance of tires and suspensions has been improved. It is also known to perform four-wheel steering in which both front wheels and rear wheels are steered in response to steering wheel operations.

[0003] In typical four-wheel steering, the rear wheels are steered to the same phase as the front wheels while the vehicle is turning in a medium to high speed range. Then, in order to further improve the steering stability, the primary delay control for delaying the timing of the rear wheel steering operation with respect to the front wheel steering in order to reduce the delay of the vehicle following the steering in the transient state from the initial steering to the steady turning. Also, phase inversion control in which the rear wheels are momentarily reversed in the early phase of turning and yaw rate proportional control in which the rear wheels are steered according to the yaw rate generated in the vehicle during turning of the vehicle have been proposed. This type of four-wheel steering control is useful in a normal vehicle running state, that is, in a non-limit state in which the behavior of the vehicle changes linearly with respect to the steering operation by the driver.

[0004]

However, for some reason, a limit state may be reached in which the vehicle responds non-linearly to the steering operation. In this limit state,
The vehicle does not turn in response to the operation of the steering wheel, so that the driver excessively operates the steering wheel. As a result, the vehicle enters a panic state where the vehicle behavior may not be able to converge. When the panic state continues, the vehicle behavior becomes divergent, and the vehicle behavior cannot be controlled by operating the steering wheel.

For example, a divergent vehicle behavior may occur during a lane change. Figure 1 shows that a vehicle that was initially in a non-limit state becomes limit state during a lane change,
This shows a case where the vehicle behavior cannot be converged. In the illustrated example, the driver starts turning the steering wheel at time t0 to start the lane change. At this point, the vehicle is in the non-limit state, and accordingly, the vehicle turns in response to a subsequent steering operation. That is, the yaw rate of the vehicle changes in the same direction as the change direction of the steering wheel angle (see FIGS. 2 and 3).

However, in order to complete the lane change, t1
When the driver turns back the steering wheel at that time, the vehicle is already in the limit state, and even if the steering wheel is turned back, the yaw rate gradually increases for a while. That is, the direction of the vehicle does not change much. In other words, when the vehicle enters the limit state, the direction of the vehicle (yaw rate) causes a large phase delay with respect to the steering wheel operation. As described above, if the direction of the vehicle does not change even when the steering wheel is turned back, the driver further turns the steering wheel back.

[0007] When the grip force of the tires starts to recover near the time point t2, the direction of the vehicle starts to change to the steering wheel return direction, and after that, in response to the excessive steering wheel return operation performed so far. The direction of the vehicle changes suddenly (the magnitude of the yaw rate increases rapidly). Thus, when the direction of the vehicle suddenly changes, the driver cannot follow the change in the vehicle behavior, and starts operating the steering wheel in the opposite direction after reaching time t4. That is, the steering operation causes a large phase delay with respect to the change in the vehicle behavior.

[0008] Thereafter, a significant delay in the response of the vehicle to the steering wheel operation, resulting in excessive steering wheel operation,
A sudden change in vehicle behavior, a large delay in steering wheel operation due to a change in vehicle behavior, and excessive steering wheel operation occur cyclically. In such a limit state where the response delay of the vehicle to the steering wheel operation and the response delay of the driver to the vehicle behavior occur, the driver performs excessive steering operation in an attempt to converge the vehicle behavior. Then, the vehicle enters a panic state where the vehicle behavior may not be able to converge.

If it is possible to immediately determine that the vehicle has entered a limit state or a panic state, it is considered that some measures can be taken to converge the behavior of the vehicle. However, no such attempt has been made so far.
Accordingly, an object of the present invention is to provide a method for determining a limit state of a vehicle that can immediately determine entry into a limit state where the vehicle makes a nonlinear response to steering.

Another object of the present invention is to provide a method for judging a panic state, which can immediately determine the entry into a panic state caused by excessive steering in a limit state, thereby preventing a divergent vehicle behavior. Is to provide.

[0011]

Limit state determination method of the vehicle according to the present invention, in order to solve the above-mentioned object, the vehicle behavior parameters and steering parameters
Is detected at every predetermined control cycle, the change direction of the vehicle behavior parameter and the change direction of the steering parameter are obtained , and when the change direction of the vehicle behavior parameter is different from the change direction of the steering parameter, the vehicle enters the limit state. Is characterized.

Preferably, the yaw rate of the vehicle is used as the vehicle behavior parameter, and the steering wheel angle is used as the steering parameter. Further, only when the vehicle speed exceeds a predetermined vehicle speed, the change direction of the vehicle behavior parameter and the change direction of the steering parameter are obtained . That is, the parameters
Detect the direction of change . The panic state determination method of the present invention determines whether or not a first condition that a vehicle behavior parameter changes in a direction different from a direction in which a steering parameter changes is satisfied, and determines whether the first condition is satisfied while the first condition is satisfied. It is determined whether or not a second condition that the amount of change in the steering parameter from the time when the condition is first satisfied exceeds a threshold value is satisfied.
When the condition is satisfied, it is determined that the vehicle has entered a panic state.

Preferably, the steering wheel angle is used as the steering parameter, and the yaw rate of the vehicle is used as the vehicle behavior parameter. Only when the vehicle speed exceeds the predetermined vehicle speed, it is determined whether the first and second conditions are satisfied.

[0014]

[ Operation ] To determine the limit state, the vehicle behavior parameters and the operation
The steering parameter and the steering parameter are detected at each predetermined control cycle, and the change direction of the vehicle behavior parameter and the change direction of the steering parameter are obtained and compared with each other. For example, the yaw of a vehicle
The rate and the steering wheel angle are periodically detected, and the sign of the vehicle yaw rate change rate and the sign of the steering wheel angle change rate (steering wheel steering speed) are detected and compared. In a non-limit state in which the vehicle behavior responds linearly to steering, the direction of change in vehicle behavior does not differ from the direction of change in steering, although there is some response delay. On the other hand, in the limit state where the vehicle behavior responds non-linearly to steering, even if the steering wheel is turned back due to the large phase delay of the yaw rate with respect to the steering wheel angle, the yaw rate remains unchanged before the steering wheel turning back for a while. There is a phenomenon in which the vehicle gradually increases in the same direction (the direction of the vehicle does not change even though the steering direction has already been reversed). In other words, in the limit state, the changing direction of the vehicle behavior is different from the changing direction of the steering.

Therefore, by comparing the change direction of the vehicle behavior parameter with the change direction of the steering parameter, it is possible to clearly distinguish whether the vehicle is in the non-limit state or the limit state. Therefore, when the change direction of the vehicle behavior parameter represented by the sign of the yaw rate change rate is different from the change direction of the steering parameter represented by the sign of the steering wheel speed, it is determined that the vehicle has entered the limit state. . That is, when the steering wheel is turned back from the plus direction to the minus direction (FIG. 4), when the steering wheel enters the hatched circular area in the first quadrant of FIG. In the case of being cut back from the minus direction to the plus direction (not shown), when entering into a circular area (not shown) existing in the third quadrant in FIG. Is determined.

In determining the panic state, it is first determined whether or not a first condition that the vehicle behavior parameter changes in a direction different from the change direction of the steering parameter is satisfied. That is, as in the case of the limit state determination, it is determined whether or not the vehicle has entered the limit state. Next, while the first condition is satisfied, that is, while the vehicle is in the limit state, the amount of change in the steering parameter (for example, the steering wheel angle) from when the first condition is first satisfied exceeds the threshold value. It is determined whether two conditions are satisfied.

Even if the vehicle is in the limit state, it does not immediately shift to the panic state in which the vehicle behavior cannot be converged, but in the limit state, the vehicle response to the steering is greatly delayed, so that excessive steering by the driver may occur. It is easy to do so, in which case it leads to a panic condition. Therefore, while the first condition is satisfied, that is, while the vehicle is in the limit state, it is continuously monitored whether or not the second condition is satisfied. When the second condition is satisfied, that is, in the limit state, excessive steering is performed. Is performed (in the case of FIG. 4, when the amount of change in the steering wheel angle increases or decreases within the circular area from the time of entry into the circular area beyond the threshold), it is determined that the vehicle has entered the panic state. .

When it is determined that the vehicle has entered the limit state or the panic state as described above, the driver is required to enter the limit state or the panic state in order to prevent the vehicle behavior from becoming unable to converge. You will be able to take some measures, such as notifying you. During a low-speed running of the vehicle, generally, the behavior of the vehicle can be made to converge by operating the steering wheel of the driver. Thus, in certain aspects of the invention,
Changing direction up for vehicle behavior parameters for the limit state determination
And the direction of change of the steering parameters and
The determination of the first and second conditions for comparison or panic determination of direction, intends seen rows when the vehicle speed exceeds a predetermined vehicle speed.

[0019]

Referring to FIG. 5, the left and right front wheels 1L, 1R of a vehicle to which the method for judging a limit state and a panic state according to one embodiment of the present invention is connected to a front wheel power steering device 2 via a tie rod 3. Have been. This device 2
Is a four-wheel steering device which cooperates with various elements to be described later, and includes a rack and pinion mechanism (not shown) operated by the steering handle 4 and a front wheel steering actuator (not shown) comprising a hydraulic cylinder connected thereto. (Not shown).

The front wheel steering actuator is connected to one hydraulic pump 7 of the pump unit 6 via a front wheel steering valve 5 operated by a steering handle 4. The pump unit 6 is composed of a double pump driven by an engine 8, and the other hydraulic pump 9 is connected to a rear wheel steering actuator 11 via a rear wheel steering valve 10.
It is connected to the.

The rear wheel steering actuator 11 is also composed of a hydraulic cylinder, and the piston rod of the actuator 11 is connected to the left and right rear wheels 13L, 13R via tie rods 12. In FIG. 5, reference numeral 14 indicates a reservoir tank. The front wheel steering actuator operates according to the steering direction by supplying hydraulic oil from a hydraulic pump 7 via a front wheel steering valve 5 when the steering handle 4 is steered. On the other hand, the operation of the rear wheel steering actuator 11 is controlled by the controller 15. That is, when the steering handle 4 is steered, the controller 15 supplies an operation control signal SR suitable for the vehicle running state to the rear wheel steering valve 10, whereby the hydraulic pump 9 controls the rear wheel steering via the valve 10. The operating oil pressure supplied to the actuator 11 is controlled.

The controller 15 is electrically connected to various sensors and meters in connection with the above-described front and rear wheel steering actuator operation control and panic state determination described below. That is, the controller 15 includes a sensor signal indicating a vehicle speed V from meters and operating states of various devices, a sensor signal indicating a steering wheel angle θH from a steering wheel angle sensor 16, and a sensor signal indicating the actual steering angle from a rear wheel steering angle sensor 17. A sensor signal indicating the wheel steering angle δRa is supplied, and further, a sensor signal indicating the power steering pressure (the operating pressure of the power steering device 2 and thus the front wheel steering actuator) is supplied. In the present embodiment, a pair of pressure sensors 18 and
The difference between the pressures PL and PR in the left and right pressure chambers (not shown) of the front wheel steering actuator respectively detected by 19 is determined as the power steering pressure. Further, the controller 15 is connected to a yaw rate sensor 60 for detecting the actual yaw rate of the vehicle (the speed of the rotation movement around the center of gravity of the vehicle) Y, and a signal indicating the actual yaw rate Y from the sensor 60 is sent to the controller 15. It is supplied to.

Controller 1 not directly related to the present invention
5, the controller 15 includes a steering wheel angle sensor 16 and a pressure sensor 1.
8, 19, the road surface μ is calculated from the data from the vehicle speed sensor 26 and the meter, the vehicle running mode is determined, and the operation control signal SR is further calculated based on the sensor data, the road surface μ and the running mode. The output is directed toward the wheel steering valve 10.

Hereinafter, referring to FIG.
Will be described below. While the vehicle is running, the controller 15 repeatedly executes the determination process of FIG. 6 at a predetermined cycle of, for example, 5 milliseconds. In each cycle of the determination process, the controller 1
5 subtracts a predetermined value, for example, "2" from the panic flag (step S1), and then determines whether the panic flag is negative (step S2). This panic flag is stored in, for example, a register (not shown) built in the controller 15, and its initial value is set to “0” in an initialization process (not shown).

If the panic flag is negative, step S2
Is determined, the controller 15 resets the panic flag to "0" so that the panic flag always takes a value equal to or greater than "0" (step S3), and then the vehicle speed V detected by the vehicle speed sensor 26 is determined. Vehicle speed threshold value, for example, 30
km / h is determined (step S
4). If the panic flag is not negative, step S2
When the determination is made in step S2, the program proceeds from step S2 to step S4.

The vehicle speed V does not exceed the threshold, and
When it is determined in step S4 that the vehicle is traveling in the low speed range, the controller 15 determines that the determination of the limit state and the panic state in the low speed range is unnecessary. In this case, the controller 15 adds "1" to the value of the built-in wait counter (step S5), and then determines whether the wait counter value is larger than a wait counter threshold value, for example, "30". (Step S6). In the initialization process, a wait counter threshold value is set as the wait counter initial value in the wait counter.

If it is determined in step S6 that the wait counter value is larger than the wait counter threshold, the controller 15
Sets the positive steering amount and the negative steering amount representing the steering amounts in the plus direction and the minus direction (for example, corresponding to left turn and right turn, respectively) from the time when the vehicle enters the limit state to the present time to “0”. Each of them is set, and a wait counter threshold is set in the wait counter (step S
7), thereby ending the determination processing in the current cycle,
It returns to step S1. On the other hand, if it is determined that the wait counter value is not larger than the wait counter threshold, the process proceeds to step S
Step 7 is skipped and the process returns to step S1.

Thereafter, while the steps S1 to S6 or the steps S1 to S7 are repeatedly executed, if the vehicle speed V exceeds the vehicle speed threshold, the determination result in the step S4 becomes positive. In this case, the controller 15 determines in step S8 that the steering wheel angle data θ
Yn rate data Y from Hn and yaw rate sensor 60
n and read controller 15 in the previous cycle.
Angle data θHn-1 stored in the memory (not shown)
And the yaw rate data Yn-1 is read from the memory.
Next, the controller 15 calculates the deviation (θn−θn−1) between the current steering wheel angle θn and the previous steering wheel angle θn−1 as the current steering wheel speed Δθn, and calculates the current yaw rate Yn
(Yn-Yn-1) between the current yaw rate Yn-1 and the previous yaw rate Yn-1 is calculated as the current yaw rate change rate .DELTA.Yn. Then, the controller determines whether the sign of the steering wheel speed Δθn (the changing direction of the steering wheel angle θH as the steering parameter) is positive and the sign of the yaw rate change rate ΔYn (the changing direction of the yaw rate Y as the vehicle behavior parameter) is negative. It is determined whether or not.

If the vehicle is in the non-limit state, since the steering wheel speed .DELTA..theta.n and the yaw rate change rate .DELTA.Yn have the same sign, the result of the determination in step S8 is negative. In this case, the controller 15 determines whether the sign of the steering wheel steering speed Δθn is negative and the sign of the yaw rate change rate ΔYn is positive (step S9). If the vehicle is in the non-limit state, the determination result in step S9 is negative for the above-described reason. In this case, the program executes step S
After step 5 and subsequent steps, the process returns to step S1.

As is apparent from the above description, when the vehicle is running in the low speed range or the other middle or high speed range in the non-limit state, steps S1, S2 and S4 to S4 are performed.
S7, or steps S1, S2, S4, S8, S9 and
And S5 to S7 are repeatedly executed. Thereafter, when the vehicle is in the limit state, the driver
Is turned back from the minus direction to the plus direction. In this case, the sign of the steering wheel speed ΔθH is positive. On the other hand, when the vehicle is in the limit state, a significant response delay of the vehicle to steering occurs, and for a while after the turning back of the steering wheel, the yaw rate change rate ΔY has a negative sign which is the same sign as that before the turning back of the steering wheel. . Therefore, the determination result of step S8 is affirmative, and the controller 15 determines that the vehicle has entered the limit state.

After determining that the vehicle has entered the limit state, the controller 15 continues to monitor whether or not the vehicle has shifted from the limit state to the panic state. Here, since the entry into the limit state has become apparent due to the operation of the steering wheel in the plus direction, the amount of steering operation in the plus direction after the point of entry into the limit state is monitored. For this reason, in step S10, the controller 15 adds the steering wheel speed ΔθH calculated in step S8 of the current cycle to the plus steering amount, and stores the addition result as a new plus steering amount in the memory. On the other hand, the minus steering amount and the waiting counter are each reset to “0”. Next, the controller 15
Indicates that the updated plus steering amount is equal to the steering angle threshold (for example, 2
5 degrees) (step S1).
1). At the time of entering the limit state, the positive steering amount is normally “0”, and therefore, the steering amount is increased by the steering wheel speed ΔθH.
Is usually not immediately exceeded the steering angle threshold value. In this case, step S11
Is negative, and the program proceeds to step S1
Return to

In the next and subsequent determination cycles, if the limit state in which the determination result in step S8 is affirmative continues, every time the determination cycle is executed, the steering wheel is turned to the positive steering amount in step S10. The speed ΔθH is added. The steering wheel speed .DELTA..theta.H that is cumulatively added in this manner, that is, the positive steering amount, represents the positive steering amount after the point of entry into the limit state caused by the positive steering. Also, handle angle θH
Since the plus steering amount is calculated based on the steering wheel speed ΔθH that is ahead of the actual steering amount, the plus steering amount thus calculated represents a predicted value of the steering amount that is ahead of the actual steering amount.

If the plus steering amount does not exceed the steering angle threshold, it is determined that the vehicle has not yet entered the panic state, and the process returns to step S1. If it is determined in step S11 of the subsequent determination cycle that the plus steering amount has exceeded the steering angle threshold value, the controller 15 performs excessive steering after the point of entry into the limit state, and thus the vehicle enters the panic state or Determines that there is a risk of entering a panic state. In this case, the controller 15 sets the panic flag to a predetermined value indicating entry into a panic state, for example, “1000” (Step S).
12). Next, the program returns to step S1.

When the steering wheel 4 is turned back from the plus direction to the minus direction in the limit state, the sign of the steering wheel speed .DELTA..theta.H becomes negative, while the yaw rate change rate .DELTA.Y remains unchanged before the steering wheel is turned back. And a positive sign which is the same sign as. in this case,
Although the determination result of step S8 is negative, step S9
Is positive, so that the controller 15
Determines that the vehicle has entered the limit state.

Here, the entry into the limit state has become apparent due to the operation of the steering wheel in the minus direction. Therefore, in order to monitor the amount of steering operation in the minus direction after the entry into the limit state, the controller 15 corresponds to step S10. In step S13, the current steering wheel speed Δθ
H is added to the negative steering amount to update the negative steering amount. On the other hand, the plus steering amount and the waiting counter are each reset to “0”. Next, the controller 15
It is determined whether or not the updated negative steering amount is smaller than the product of the steering angle threshold value and “−1” (step S14).
At the time of entering the limit state, the minus steering amount is normally “0”, and therefore, normally, the determination result in step S14 is negative, and the program returns to step S1.

In the next and subsequent determination cycles, if the limit state in which the determination result in step S9 becomes affirmative continues, the steering wheel is turned to a negative steering amount in step S13 every time the determination cycle is executed. The speed ΔθH is added. If the negative steering amount is not smaller than the product of the steering angle threshold value and "-1", it is determined that the vehicle has not yet entered the panic state, and the process returns to step S1.

If it is determined in step S14 of the subsequent determination cycle that the minus steering amount is smaller than the product of the steering angle threshold value and "-1", the controller 15 performs excessive steering after the point of entry into the limit state. Therefore, it is determined that the vehicle has entered the panic state or may enter the panic state, and the panic flag is set to "1000" (step S12).

In step S1 of the determination cycle following the determination cycle in which the entry into the panic state is determined, "2" is subtracted from the panic flag. Therefore, after the vehicle has once entered the panic state, if the steering wheel operation is continuously performed so as to correct the excessive steering, each step S11 of the determination cycle after the point of entering the panic state is performed.
The result of the determination in (or S14) is negative, and the value of the panic flag gradually decreases, so that the panic flag reaches “0” indicating the cancellation of the panic state. On the other hand, if the excessive steering is not corrected, step S11 (or S14)
The panic flag is reset to "1000" which indicates a panic state each time the determination result in is positive.

After the panic flag is set to "1000", the mode shifts from the middle to high speed range to the low speed range and step S4
Is negative, or if the limit state is eliminated and the results of the determinations in steps S8 and S9 are negative, the value of the wait counter is set to "1" each time the determination cycle is executed.
Is incremented by one (step S5). Therefore,
When the vehicle travels in the low-speed range or the non-limit state for a certain period of time, the wait counter value exceeds the wait counter threshold value (step S6), and the initial values of the plus steering amount and the minus steering amount used for the next panic determination are determined. Is "0"
(Step S7).

The present invention is not limited to the above embodiment, but can be variously modified. For example, in the above embodiment, both the limit state determination and the panic state determination are performed, but only the limit state determination may be performed. In this case, for example, only steps S1 to S9 in FIG. 6 are performed, and when the determination result in step S8 or S9 is affirmative, detection of entry into the limit state is performed.

In the embodiment, the panic flag is set to a predetermined value when the occurrence of the panic state is determined following the occurrence of the limit state. However, when the occurrence of the limit state or the panic state is determined, this is set. An alarm may be issued to notify the driver. Further, in the embodiment, in relation to the determination of the panic state, the steering amount after the point of entry into the limit state is calculated based on the steering wheel steering speed, and thereby, the predicted steering amount is obtained. The steering amount may be obtained based on the steering wheel angle at the time of entry and the steering wheel angle at the present time.

In the embodiment, the yaw rate change rate as a vehicle body behavior parameter is calculated based on the output of the yaw rate sensor. However, the yaw rate change rate is calculated based on the difference between the outputs from two lateral acceleration sensors (not shown). You may. Further, in the embodiment, the case where the method of the present invention is applied to a four-wheel steered vehicle has been described, but the present invention is also applicable to a two-wheel steered vehicle. Further, the configuration of the four-wheel steering device and the control rules related to the four-wheel steering are not limited to those of the embodiment.

[0043]

As described above, the method for judging the limit state of a vehicle according to the present invention includes a vehicle behavior parameter and a steering parameter.
Is detected at every predetermined control cycle, the change direction of the vehicle behavior parameter and the change direction of the steering parameter are obtained , and when the change direction of the vehicle behavior parameter is different from the change direction of the steering parameter, the vehicle enters the limit state. , It is possible to immediately determine entry into a limit state where the vehicle makes a non-linear response to steering.

Further, the panic state determination method of the present invention
It is determined whether or not a first condition that a vehicle behavior parameter changes in a direction different from a direction in which a steering parameter changes is satisfied, and while the first condition is satisfied, the steering from when the first condition is first satisfied is determined. It is determined whether or not a second condition that the amount of change of the parameter exceeds the threshold is satisfied, and it is determined that the vehicle enters a panic state when the second condition is satisfied. It is possible to immediately determine whether or not there is a possibility that the vehicle will enter a panic state caused by the vehicle, thereby preventing divergent vehicle behavior.

According to a specific embodiment of the present invention in which the yaw rate of the vehicle is used as the vehicle behavior parameter and the steering wheel angle is used as the steering parameter, the behavior and the steering state of the vehicle can be accurately grasped. State determination can be performed properly. The detection of the change direction of the vehicle behavior parameter and the change direction of the steering parameter for the limit state determination, or the determination of the first and second conditions for the panic state determination, is performed when the vehicle speed exceeds a predetermined vehicle speed. According to a particular aspect of the present invention which was run Migihitsuji, it can be omitted limit state determination and panic determination not very useful in the low speed range where it is possible to converge the vehicle behavior by the handle operation.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating a case where a vehicle behavior becomes unable to converge with a lane change.

FIG. 2 is a graph showing changes in the steering wheel angle and the yaw rate with respect to the passage of time during the lane change shown in FIG.

FIG. 3 is a graph showing a relationship between a change in a steering wheel angle and a change in a yaw rate shown in FIG. 2;

FIG. 4 is a graph showing a detection area of a limit state and a panic state of a vehicle as a circular area according to the present invention.

FIG. 5 is a schematic view showing a four-wheel steering vehicle to which a limit state and panic state determination method according to an embodiment of the present invention is applied.

FIG. 6 is a flowchart showing a limit state and panic state determination process executed by the controller of FIG. 5;

[Explanation of symbols]

 4 Steering handle 15 Controller 16 Handle angle sensor 26 Vehicle speed sensor 60 Yaw rate sensor

Continuation of front page (72) Inventor Nobuo Momose 5-33-8 Shiba, Minato-ku, Tokyo Inside Mitsubishi Motors Corporation (56) References JP-A-6-227419 (JP, A) (58) Investigated Field (Int.Cl. ⁶ , DB name) B62D 6/00

Claims (6)

(57) [Claims] 1. A vehicle behavior parameter and a steering parameter.
The detected for each predetermined control cycle, determine the direction of a change in the change direction as the steering parameters of the vehicle behavior parameters,
A method for determining a limit state of a vehicle, comprising determining that the vehicle has entered a limit state when a change direction of the vehicle behavior parameter is different from a change direction of the steering parameter. 2. The method according to claim 1, wherein a yaw rate of the vehicle is used as the vehicle behavior parameter, and a steering wheel angle is used as the steering parameter. 3. A process according to claim vehicle speed is characterized only, to seek the direction of change of the steering parameters and change direction of the vehicle behavior parameters when exceeds a predetermined vehicle speed 1
3. The method for determining a limit state of a vehicle according to claim 1. 4. It is determined whether or not a first condition that a vehicle behavior parameter changes in a direction different from a direction in which a steering parameter changes is satisfied, and while the first condition is satisfied,
It is determined whether or not a second condition that the amount of change in the steering parameter from the time when the first condition is first satisfied exceeds a threshold is satisfied, and a panic state is entered when the second condition is satisfied. And a panic state determination method. 5. The panic state determination method according to claim 4, wherein a steering wheel angle is used as the steering parameter, and a yaw rate of the vehicle is used as the vehicle behavior parameter. 6. The panic state determination method according to claim 4, wherein whether or not the first and second conditions are satisfied is determined only when the vehicle speed exceeds a predetermined vehicle speed.