JP2007230262A - Behavior control device of vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a vehicle behavior control device capable of preventing the starting of vehicle behavior control at an early stage and the enlargement of the yaw moment generated by the vehicle behavior control when a vehicle item is different from a vehicle item in constituting a vehicle model. <P>SOLUTION: This vehicle behavior control device computes a vehicle turning state controlled variable VF in accordance with a yaw rate error Yrerr when the size of the yaw rate error Yrerr which is the deviation of a target yaw rate and a real yaw rate is larger than a dead zone. The vehicle behavior control device acquires steering angle slippage θerr (equivalent to real tire cutting angle deviation) from a steering angle θ when the vehicle is in a straight forward travelling state. Thereafter, the larger the vehicle behavior control device makes the dead zone, the larger the vehicle behavior control device makes the size of the steering angle slippage θerr. Additionally, the vehicle behavior control device changes the size of the vehicle turning state controlled variable VF in correspondence with the size of the steering angle slippage θerr. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a vehicle behavior control device that controls the behavior of a vehicle by controlling braking force and / or driving force.

Conventionally, the target yaw rate is obtained by applying the detected vehicle speed and tire turning angle to the vehicle model representing the behavior of the vehicle, and the deviation between the target yaw rate and the actual yaw rate (actual yaw rate) detected by the yaw rate sensor. When the value exceeds the predetermined reference value (dead zone), the control amount such as braking force to generate the yaw moment based on the magnitude of the deviation is determined and the vehicle behavior is controlled using the control amount. A vehicle behavior control device is known. Vehicle models employed in such devices generally include vehicle wheelbase length, vehicle weight, front and rear wheel cornering power when standard tires are mounted, distance from vehicle center of gravity to front and rear wheel axles, etc. It is built based on the specifications of the vehicle including.
JP 2005-206005 A

  However, for example, when the actual vehicle alignment deviates from the alignment at the time of building the vehicle model, or the cornering power when building the vehicle model due to the occurrence of uneven wear of specific tires or a decrease in air pressure. If the vehicle specification is different from the vehicle specification when the vehicle model is constructed, the vehicle behavior (target yaw rate) obtained based on the vehicle model and the actual vehicle behavior are expressed. Deviations from the model occur. For this reason, vehicle behavior control may be started early, or the yaw moment generated by vehicle behavior control may increase.

The vehicle behavior control device according to the present invention is made to cope with the above-described problem,
Control tire cutting angle acquisition means for acquiring a control tire cutting angle corresponding to a difference between a predetermined reference tire cutting angle and an actual tire cutting angle;
Target vehicle turning state amount acquisition means for acquiring a target vehicle turning state amount representing a turning state targeted by the vehicle based on the control tire turning angle;
An actual vehicle turning state amount acquisition means for acquiring an actual vehicle turning state amount that is an actual turning state of the vehicle;
Obtaining a vehicle turning state control amount for changing the turning state of the vehicle so that a deviation between the target vehicle turning state amount and the actual vehicle turning state amount is small, and to the vehicle turning state control amount Vehicle turning state control means for executing vehicle turning state control for applying a corresponding force to the vehicle;
Is provided.

Furthermore, this vehicle behavior control device
An estimated tire turning angle equivalent value corresponding to a tire turning angle from the front-rear direction of the vehicle based on the acquired actual vehicle turning state amount when the vehicle turning state control by the vehicle turning state control means is not executed. (E.g., estimated steering angle) is estimated, and an actual tire turning angle equivalent value (e.g., actual steering angle) corresponding to the actual tire turning angle from the front-rear direction of the vehicle is acquired, and the estimated tire Tire turning angle deviation equivalent value acquisition means for acquiring a tire turning angle deviation equivalent value (for example, steering angle deviation) corresponding to the difference between the turning angle equivalent value and the equivalent tire turning angle equivalent value;
Vehicle turning state control amount changing means for changing the vehicle turning state control amount used by the vehicle turning state control means based on the acquired tire turning angle deviation equivalent value;
Is provided.

  In this specification, the “value corresponding to a certain parameter” is a value that increases as the size of the parameter increases, and that has the same or opposite sign as the sign representing the sign of the parameter. Is defined as The “parameter” in the present specification includes, for example, the above-mentioned “difference between the predetermined reference tire cutting angle and the actual tire cutting angle”, “actual tire cutting angle from the front-rear direction of the vehicle”, and the like. .

  According to this, a predetermined reference tire turning angle (for example, a tire turning angle necessary for a vehicle to travel straight, usually 0 degrees with respect to the vehicle longitudinal direction) and an actual tire turning angle A control tire turning angle corresponding to the difference is acquired based on, for example, a steering operation angle (ie, steering angle) from the neutral position of the steering wheel.

  On the other hand, a target vehicle turning state amount representing a turning state targeted by the vehicle is acquired based on the control tire turning angle, and a deviation between the target vehicle turning state amount and the actual vehicle turning state amount is calculated, A vehicle turning state control amount for changing the turning state of the vehicle so as to reduce the magnitude of the deviation is acquired. Then, vehicle turning state control in which a force corresponding to the acquired vehicle turning state control amount is applied to the vehicle is executed.

  Further, the estimated tire turning angle corresponding to the tire turning angle from the front-rear direction of the vehicle based on the actual vehicle turning state amount acquired when the vehicle turning state control by the vehicle turning state control means is not executed. An equivalent value is estimated, and an actual tire turning angle equivalent value corresponding to the actual tire turning angle from the front-rear direction of the vehicle is acquired. Then, a tire turn angle deviation equivalent value corresponding to the difference between the estimated tire turn angle equivalent value and the actual tire turn angle equivalent value is acquired, and the vehicle turning state control means uses the tire turn angle deviation equivalent value based on the tire turn angle deviation equivalent value. The vehicle turning state control amount is changed.

  The estimated tire turn angle equivalent value corresponding to the “tire turn angle from the front and rear direction of the vehicle” estimated based on the actual vehicle turning state amount when the vehicle turning state control is not executed is the alignment (caster angle, camber angle). In the case where it is assumed that there is no change in vehicle specifications (factors affecting vehicle behavior) such as change in angle and toe angle), uneven wear of specific tires, and decrease in air pressure of specific tires, etc. This is a value corresponding to the “tire turning angle with reference to the longitudinal direction of the vehicle”, which is estimated that the actual vehicle turning state amount will be obtained.

  Accordingly, the tire turning angle deviation equivalent value reflects a change in the vehicle specifications, and therefore the degree of correctness of the target vehicle turning state amount decreases as the tire turning angle deviation equivalent value increases. Therefore, if the vehicle turning state control amount is changed based on the tire turning angle deviation equivalent value as in the above configuration, the vehicle behavior control is executed early or the yaw moment generated by the vehicle behavior control increases. Can be avoided.

in this case,
The actual vehicle turning state quantity acquisition means includes
The actual vehicle turning state quantity is configured to acquire at least one of an actual yaw rate of the vehicle and an actual lateral acceleration of the vehicle,
The tire turning angle deviation equivalent value acquisition means includes:
It is determined whether the vehicle is in a straight traveling state based on at least one of the acquired yaw rate and the acquired lateral acceleration, and when it is determined that the vehicle is in a straight traveling state, the estimated tire The cut angle equivalent value is estimated to be a value corresponding to the tire cut angle from the front-rear direction of the vehicle when the tire direction coincides with the front-rear direction of the vehicle, and the tire cut angle deviation equivalent It is preferably configured to obtain a value.

  According to this, at least one of the yaw rate and lateral acceleration of the vehicle is acquired as the actual vehicle turning state quantity, and it is determined whether or not the vehicle is in a straight traveling state based on the acquired yaw rate and lateral acceleration.

  By the way, when the vehicle is not in a straight traveling state, even if the vehicle turning state control is not executed, it is necessary to consider the influence of the amount of tire slip and the road surface friction coefficient. It is not easy to obtain the estimated tire turning angle equivalent value based on the behavior of the vehicle when it is assumed that no occurrence has occurred. On the other hand, when the vehicle is in a straight traveling state, it is not necessary to consider the side slip amount and the vehicle turning state control is not generally executed. Therefore, when it is assumed that no change in the vehicle specification has occurred when the vehicle is in a straight traveling state, the tire turning angle is the reference angle (ie, the tire direction is the vehicle front-rear direction). The tire turning angle from the front-rear direction of the vehicle when they coincide is 0 degrees.

  Therefore, when the vehicle is determined to be in a straight traveling state as in the above configuration, the estimated tire turning angle equivalent value is determined from the front-rear direction of the vehicle when the tire direction matches the front-rear direction of the vehicle. If the deviation between the estimated value and the actual tire turn angle equivalent value is obtained as the tire turn angle deviation equivalent value, the tire turn angle deviation equivalent value is This is a value that accurately represents the effect of changes in specifications on vehicle behavior. As a result, according to the above configuration, it is possible to more reliably avoid the vehicle behavior control being started early or the yaw moment being increased by the vehicle behavior control.

in this case,
The target vehicle turning state quantity acquisition means is
A target yaw rate is acquired as the target vehicle turning state quantity;
The actual vehicle turning state quantity acquisition means includes
An actual yaw rate that is an actual yaw rate of the vehicle is acquired as the actual vehicle turning state quantity;
The vehicle turning state control means includes
The vehicle turning state control amount is acquired when a magnitude of a yaw rate deviation that is a difference between the target yaw rate and the actual yaw rate is equal to or greater than a predetermined threshold;
The vehicle turning state control amount changing means is
It is preferable that the vehicle turning state control amount is changed by increasing the predetermined threshold as the acquired tire turning angle deviation equivalent value increases.

  According to this, the yaw rate deviation is acquired from the target yaw rate and the actual yaw rate, and when the yaw rate deviation is equal to or greater than the predetermined threshold, the vehicle turning state control amount is acquired, and thus based on the vehicle turning state control amount. The turning state of the vehicle is controlled. On the other hand, the predetermined threshold value is obtained based on the tire turn angle deviation equivalent value so as to increase as the size of the tire turn angle deviation equivalent value increases.

  As a result, the larger the value corresponding to the tire turning angle deviation is, that is, the more the vehicle model deviates from the original vehicle specifications, the more difficult it is to obtain the vehicle turning state control amount. Since it becomes difficult to start the state control, it is possible to prevent the vehicle turning control from being started early.

Or
The target vehicle turning state quantity acquisition means is
A target yaw rate is acquired as the target vehicle turning state quantity;
The actual vehicle turning state quantity acquisition means includes
An actual yaw rate that is an actual yaw rate of the vehicle is acquired as the actual vehicle turning state quantity;
The vehicle turning state control means includes
The vehicle turning state control amount that increases as the magnitude of the yaw rate deviation, which is the difference between the target yaw rate and the actual yaw rate, increases based on the yaw rate deviation,
The vehicle turning state control amount changing means is
It is preferable that the size of the vehicle turning state control amount is decreased as the acquired tire turning angle deviation equivalent value increases.

  According to this, the yaw rate deviation is acquired from the target yaw rate and the actual yaw rate, and the vehicle turning state control amount is determined such that the larger the yaw rate deviation, the larger the vehicle turning state control amount. On the other hand, as the tire turning angle deviation equivalent value is larger, that is, as the vehicle specification deviates from the original vehicle specifications, the vehicle turning state control amount decreases so that the vehicle turning state control amount decreases. Be changed. Therefore, it is possible to avoid an increase in the moment generated by the vehicle turning control due to the vehicle specification deviating from the original vehicle specification.

Or
The target vehicle turning state quantity acquisition means is
A target yaw rate is acquired as the target vehicle turning state quantity;
The actual vehicle turning state quantity acquisition means includes
An actual yaw rate that is an actual yaw rate of the vehicle is acquired as the actual vehicle turning state quantity;
The vehicle turning state control means includes
Based on the yaw rate deviation that is the difference between the target yaw rate and the actual yaw rate, the vehicle turning state control amount is acquired such that the magnitude of the vehicle turning state control amount increases as the magnitude of the yaw rate deviation increases. Composed of
The vehicle turning state control amount changing means is
The vehicle turning state control amount is reduced by decreasing the magnitude of the yaw rate deviation used for obtaining the vehicle turning state control amount in the vehicle turning state control as the acquired tire turning angle deviation equivalent value increases. It is preferably configured to change.

  According to this, a yaw rate deviation (hereinafter referred to as “actual yaw rate deviation” for convenience) is acquired from the target yaw rate and the actual yaw rate, and the magnitude of the vehicle turning state control amount increases as the actual yaw rate deviation increases. The vehicle turning state control amount is obtained. On the other hand, the larger the tire turning angle deviation equivalent value is, the smaller the yaw rate deviation (hereinafter referred to as “control yaw rate deviation”) used when obtaining the vehicle turning state control amount in the vehicle turning state control. As described above, the control yaw rate deviation is obtained based on the actual yaw rate deviation and the tire turning angle deviation equivalent value.

  As a result, since the magnitude of the control yaw rate deviation decreases as the vehicle specifications deviate from the original vehicle specifications, the magnitude of the vehicle turning state quantity decreases. Therefore, it is possible to avoid an increase in the moment generated by the vehicle turning control.

  Further, for example, when the magnitude of the control yaw rate deviation is changed to a small value by subtracting a value (dead zone) determined based on the tire turning angle deviation equivalent value from the magnitude of the actual yaw rate deviation, the magnitude of the actual yaw rate deviation is large. The vehicle turning state amount is not acquired until the value becomes greater than or equal to the value determined according to the tire turning angle deviation equivalent value. As a result, since the vehicle turning state control becomes difficult to start as the vehicle specification deviates from the original vehicle specification, the vehicle turning control can be prevented from starting early.

Further, the tire turning angle deviation equivalent value acquisition means includes:
It is preferable that the steering angle from the neutral position of the steering wheel of the vehicle when it is determined that the vehicle is in the straight traveling state is acquired as the tire turning angle deviation equivalent value.

  According to this, the tire turning angle deviation equivalent value can be easily obtained from the means for detecting the steering operation amount such as the steering angle sensor.

  In addition, when the predetermined reference tire turning angle at the time of determining the control tire turning angle described above is “a reference tire turning angle necessary for driving the vehicle straight”, the reference tire turning angle is usually the tire direction. Is the tire turning angle from the front-rear direction of the vehicle when it matches the front-rear direction of the vehicle (that is, 0 degrees, hereinafter referred to as “neutral tire angle”). However, there are cases where the “reference tire turning angle necessary for driving the vehicle straight” differs from the neutral tire angle due to changes in vehicle specifications that affect vehicle behavior such as vehicle alignment. In such a case, the control tire turning angle is, for example, “steering angle (steering angle from the neutral position of the steering wheel) corresponding to the tire turning angle from the front-rear direction of the vehicle when the vehicle is maintained in the straight traveling state. ) "And obtained based on the difference between the steering angle and the" actual steering angle (steering angle from the neutral position of the steering wheel) "corresponding to the actual tire turning angle from the front-rear direction of the vehicle. .

  Embodiments of a vehicle behavior control apparatus according to the present invention will be described below with reference to the drawings. FIG. 1 shows a schematic configuration of a vehicle behavior control apparatus 10 according to this embodiment.

  The vehicle behavior control device 10 is mounted on a vehicle (automobile) 11. The vehicle 11 includes a right front wheel 12FR, a left front wheel 12FL, a right rear wheel 12RR, a left rear wheel 12RL, a steering wheel 14, a steering device 16, a right tie rod 18R, a left tie rod 18L, a hydraulic circuit 22, A right front wheel cylinder 24FR, a left front wheel cylinder 24FL, a right rear wheel cylinder 24RR, a left rear wheel cylinder 24RL, a brake pedal 26, and a master cylinder 28 are provided.

  The vehicle behavior control device 10 includes an electronic control unit (hereinafter referred to as ECU) 30, a right front wheel speed sensor 32FR, a left front wheel speed sensor 32FL, a right rear wheel speed sensor 32RR, a left rear wheel speed sensor 32RL, and a steering angle sensor 34. , A warning light 36, a yaw rate sensor 38, and a lateral acceleration sensor 40 are provided.

  The right front wheel 12FR and the left front wheel 12FL, which are steering wheels, are steered via a right tie rod 18R and a left tie rod 18L by a rack and pinion type steering device 16 driven in response to turning of the steering wheel 14 by the driver. It has come to be. Further, the braking force of each wheel is controlled by controlling the braking pressure of each wheel cylinder by a hydraulic circuit 22 including an oil reservoir, an oil pump, various electromagnetic valves, and the like. . The master cylinder 28 is driven according to the operation of the brake pedal 26 by the driver, and controls the braking pressure of each wheel cylinder through the hydraulic circuit 22.

  The ECU 30 includes a CPU connected to each other, a ROM that stores programs executed by the CPU and a map (lookup table) in advance, a RAM that temporarily stores data as needed, and a power-on state. It is a microcomputer comprising an interface including a back-up RAM and an AD converter for storing data and holding the stored data even when the power is shut off.

  The ECU 30 is connected to the right front wheel speed sensor 32FR, the left front wheel speed sensor 32FL, the right rear wheel speed sensor 32RR, the left rear wheel speed sensor 32RL, the steering angle sensor 34, the yaw rate sensor 38, and the lateral acceleration sensor 40. The signal is supplied. In addition, the ECU 30 is connected to a warning lamp 36 and sends a warning lamp lighting signal to the warning lamp 36 in accordance with an instruction from the CPU. Further, the ECU 30 is connected to a solenoid valve (not shown) provided in the hydraulic circuit 22 and controls the braking pressure of each master cylinder by sending a drive signal to these solenoid valves in accordance with instructions from the CPU. ing.

  Each wheel speed sensor (32FR, 32FL, 32RR, 32RL) is provided in the vicinity of each wheel (12FR, 12FL, 12RR, 12RL), and the wheel speed (rotational speed) of each wheel (Vwfr, Vwfl, Vwrr, Vwrl). Is supposed to be detected. The steering angle sensor 34 is provided in a steering column connected to the steering wheel 14 and detects the steering angle θ based on a rotation angle from a predetermined neutral direction (neutral position of the steering wheel 14) of the design of the steering wheel. Absolute angle sensor. The yaw rate sensor 38 detects the yaw rate Yr of the vehicle 11 and sends the detected value to the ECU 30 as a signal. The lateral acceleration sensor 40 detects the lateral acceleration Gy of the vehicle, and sends the detected value to the ECU 30 as a signal.

(Overview of operation)
Next, the outline | summary of the action | operation of the vehicle behavior control apparatus 10 comprised as mentioned above is demonstrated.
In the following description, it is assumed that the yaw rate is a positive value when the vehicle is rotating left around the center of gravity axis of the vehicle, and is a negative value when the vehicle is rotating right. Unless otherwise specified, the tire turning angle is the tire turning angle from the front-rear direction of the vehicle (the front-rear direction of the vehicle is 0 degrees, and the tire rotation angle with respect to that direction). When it is positive, when it tries to turn right, it shall be a negative value. The lateral acceleration is a positive value when the acceleration is directed leftward of the vehicle, and is a negative value when the acceleration is directed rightward of the vehicle. The steering angle (operation angle of the steering wheel 14) is 0 when the steering wheel 14 is in the neutral position, and is a positive value when the driver rotates the steering wheel 14 from the neutral position to turn the vehicle to the left. When the driver rotates the steering wheel 14 from the neutral position in order to turn the vehicle in the right direction, a negative value is assumed.

ここでＶは車速であり、δはタイヤ切れ角であり、Ｌはホイールベースの大きさである。
また、Ｍは車重、ｌｆは車両の重心から前輪車軸までの距離、ｌｒは車両重心から後輪車軸まで距離、Ｃｆは前輪コーナーリングパワー、Ｃｒはコーナーリングパワーであり、車両諸元として予め定まっている値である。なお、本実施形態においては、（１）式のδには制御用タイヤ切れ角が代入される。制御用タイヤ切れ角とは、所定の基準タイヤ切れ角と実際のタイヤの切れ角との差である。その基準タイヤ切れ角は、通常、タイヤの向きが車両の前後方向に一致しているときの同車両の前後方向からのタイヤ切れ角（即ち、０度、中立タイヤ角）である。 In order to facilitate understanding, the operation of a conventional vehicle behavior control device will be described first. The conventional vehicle behavior control device controls the behavior of the vehicle according to the procedure described below in order to make the vehicle turn stably. First, the vehicle behavior control device calculates a target yaw rate Yrstd that is a yaw rate of a vehicle that is a target for causing the vehicle to make a stable turn by using the following equations (1) and (2).

Here, V is the vehicle speed, δ is the tire turning angle, and L is the size of the wheel base.
M is the vehicle weight, lf is the distance from the center of gravity of the vehicle to the front wheel axle, lr is the distance from the center of gravity of the vehicle to the rear wheel axle, Cf is the front wheel cornering power, and Cr is the cornering power. It is a value. In the present embodiment, the control tire turning angle is substituted for δ in equation (1). The control tire cutting angle is a difference between a predetermined reference tire cutting angle and an actual tire cutting angle. The reference tire cutting angle is usually the tire cutting angle from the front-rear direction of the vehicle when the tire direction matches the front-rear direction of the vehicle (that is, 0 degree, neutral tire angle).

  Next, the vehicle behavior control device detects the actual yaw rate (actual yaw rate) Yr of the vehicle by the yaw rate sensor 38, and calculates the yaw rate deviation Yerrr (Yerrr = Yrstd−Yr) that is the deviation between the target yaw rate and the actual yaw rate. . Then, the vehicle behavior control device acquires the vehicle turning state control amount VF from the calculated yaw rate deviation Yerrr and the map shown in FIG. 2, and the braking force of each wheel according to the acquired vehicle turning state control amount VF. The wheel cylinder hydraulic pressure of each wheel is controlled.

  On the other hand, the vehicle behavior control device 10 of the present embodiment controls the behavior of the vehicle according to the procedure as described below. First, the vehicle behavior control device 10 determines whether the vehicle is in a straight traveling state based on the actual yaw rate Yr detected by the yaw rate sensor 38, the lateral acceleration Gy detected by the lateral acceleration sensor 40, and the like. When the apparatus 10 determines that the vehicle is traveling straight, the tire angle deviation δerr (or tire outage), which is the difference between the tire angle (neutral tire angle) in the vehicle longitudinal direction and the actual tire angle, is determined. An angle deviation equivalent value θerr = steering angle deviation θerr) is acquired. Tire deviation angle deviation δerr is a change in vehicle specifications (factors affecting vehicle behavior) such as changes in alignment (caster angle, camber angle and toe angle), uneven wear of specific tires, and decrease in air pressure of specific tires. Is a value that reflects.

  Next, the vehicle behavior control apparatus 10 determines that the vehicle turning state control amount VF becomes “0” as the tire turning angle deviation δerr (or the tire turning angle deviation equivalent value θerr) increases (see FIG. 2). The vehicle turning state control amount VF is obtained so that the indicated deadzone (where deadzone> 0) increases and the vehicle turning state amount VF for the same yaw rate deviation Yerrr decreases. That is, the vehicle behavior control device 10 acquires the vehicle turning state control amount VF as shown in FIG. Then, the vehicle behavior control device 10 determines the braking force of each wheel based on the turning vehicle state control amount VF, and controls the wheel cylinder hydraulic pressure of each wheel.

  As described above, this embodiment pays attention to the fact that the difference between the vehicle specifications when the vehicle model is constructed and the vehicle specifications at the present time is reflected in the tire break angle deviation δerr (steering angle deviation θerr), The vehicle turning state control is performed based on the tire turning angle deviation δerr (steering angle deviation θerr). According to this, since the dead zone deadzone increases as the tire turning angle deviation δerr (steering angle deviation θerr) increases, it becomes difficult to start the vehicle turning state control. Even if the vehicle turning state control is started, the vehicle turning state control amount VF becomes smaller as compared with the conventional both-behavior control device as the tire turning angle deviation δerr (steering angle deviation θerr) increases. Therefore, it is possible to solve the problem that the vehicle behavior control is started early or the yaw moment generated by the vehicle behavior control is increased.

  Actually, the vehicle behavior control device 10 performs the dead zone processing on the actual yaw rate deviation Yerrr in order to obtain the same result as in the above procedure (dead zone processed yaw rate deviation). X is obtained, and the vehicle turning state control amount VF is acquired using the control yaw rate deviation X and the map shown in FIG. The dead zone process is a value obtained by subtracting the dead zone deadzone from the actual yaw rate deviation Yerrr and having the same sign as the actual yaw rate deviation Yerrr as the control yaw rate deviation X. That is, in the dead zone processing, if the yaw rate deviation Yerrr is 0 or more, Yerrr-deadzone is obtained as the control yaw rate deviation X, and if the yaw rate deviation Yerrr is smaller than 0, Yerrr + deadzone is obtained as the control yaw rate deviation X.

  On the other hand, the vehicle behavior control device 10 calculates the dead zone deadzone so that it increases as the magnitude of the tire turning angle deviation δerr (or the steering angle deviation θerr) increases. As a result of the above, by using the map shown in FIG. 4 and the control yaw rate deviation X, the vehicle turning state control amount VF of the map shown in FIG. 3 is substantially obtained.

  The vehicle behavior control device 10 performs the vehicle behavior control based on the steering angle by using the relationship between the steering angle and the tire turning angle that the tire turning angle is uniquely determined when the steering angle is determined. That is, the vehicle behavior control device 10 uses the steering angle as a value corresponding to the tire turning angle (a value corresponding to the tire turning angle). For example, when it is determined that the vehicle is traveling straight, the tire direction is the tire turning angle from the front-rear direction of the vehicle when the tire direction matches the front-rear direction of the vehicle, and a value corresponding to the tire turning angle. The steering angle is estimated to be 0 degree (neutral position). Therefore, the value corresponding to the tire turning angle deviation δerr is obtained as being equal to the steering angle when it is determined that the vehicle is in the straight traveling state.

Hereinafter, the actual operation of the vehicle behavior control device 10 will be described for each case.
(Vehicle behavior control / lateral force control)
The ECU 30 is configured to execute a routine (lateral force control routine) for controlling the lateral force of the vehicle shown in the flowchart in FIG. 5 every time a predetermined time elapses. Therefore, when the predetermined timing comes, the ECU 30 starts the processing of this routine from step 501 and proceeds to step 502 to set the vehicle speed V to the wheel speed of each wheel from each wheel speed sensor (32FR, 32FL, 32RR, 32RL). Based on (Vwfr, Vwfl, Vwrr, Vwrl), it is acquired by a known method, the steering angle θ is acquired by the steering angle sensor 34, and the actual yaw rate Yr of the vehicle is acquired by the yaw rate sensor 38. Step 502 constitutes a part of the actual vehicle turning state amount acquisition means for acquiring the actual vehicle turning state amount (Yr, V, etc.) that is the actual turning state of the vehicle.

Next, the ECU 30 proceeds to step 503 and obtains the control tire turning angle δ according to the function shown in the following equation (3). That is, the tire is obtained by substituting a value (θ−θerr) obtained by subtracting the steering angle deviation θerr derived from the steering angle θ by the dead zone calculation routine shown in FIG. 6 described later into a predetermined function f (primary function in this example). The cut angle δ is calculated. This step 503 constitutes a control tire cut angle obtaining means for obtaining a control tire cut angle δ corresponding to a difference between a predetermined reference tire cut angle and an actual tire cut angle.
δ = f (θ−θerr) (3)

  The steering angle deviation θerr is a “steering angle when the neutral position of the steering wheel 14 is used as a reference (0 degree)” necessary for the vehicle 11 to be maintained in the straight traveling state. The vehicle specifications differ from the vehicle specifications when the vehicle model was built, such as when the alignment of the vehicle is not deviated from the design alignment, or when there is no uneven wear of specific tires or a decrease in air pressure. If not, the vehicle should go straight if the steering wheel 14 is maintained in the neutral position. However, if the vehicle specifications are different from the vehicle specifications when the vehicle model is constructed, in order to make the vehicle go straight, it is necessary to maintain the tire turning angle at an angle different from the angle toward the front and rear direction of the vehicle, In that case, the steering angle deviation θerr is a non-zero value.

  At this time, if the target yaw rate is determined from the tire turning angle (for example, δ ′ = f (θ)) obtained based on the steering angle θ without considering the steering angle deviation θerr (that is, the tire turning angle deviation δerr), The target yaw rate may deviate from the yaw rate required for the vehicle. Therefore, in the present embodiment, the control tire turning angle δ is obtained based on the value (θ−θerr) obtained by subtracting the steering angle deviation θerr from the steering angle θ, and the target yaw rate Yrstd is obtained using the control tire turning angle δ. Is calculated to obtain a more accurate target yaw rate.

  However, it is considered that the relative relationship (the function f) between the actual tire turning angle and the steering angle θ does not substantially change regardless of the value of the steering angle deviation θerr. Therefore, the control tire turning angle δ obtained from the value (θ−θerr) obtained by subtracting the steering angle deviation θerr from the steering angle θ is a value based on the actual tire turning angle that changes in accordance with the steering angle θ. .

    Next, the ECU 30 proceeds to step 504 where the target yaw rate Yrstd, which is the yaw rate of the target vehicle, is acquired at the vehicle speed V and the step 503 acquired in step 502 in the above formulas (1) and (2). It is calculated by applying the control tire turning angle δ. This step 504 corresponds to a target vehicle turning state amount acquisition means for acquiring a target vehicle turning state amount (target yaw rate Yrstd) representing a target turning state of the vehicle based on the control tire turning angle δ.

Next, the ECU 30 proceeds to step 505 and calculates the yaw rate deviation Yerr by subtracting the actual yaw rate Yr from the target yaw rate Yrstd as shown in the following equation (4).
Yerrr = Yrstd−Yr (4)

Next, the ECU 30 performs the following dead zone process by performing the process of a predetermined step among the steps 506 to 510.
1.
When the absolute value of the yaw rate deviation Yerrr is equal to or greater than the dead zone deadzone (step 506) and the yaw rate deviation Yerrr is a positive value (step 507); control is performed by calculating the dead zone processing shown in the following equation (5) The yaw rate deviation X is calculated (step 509).
X = Yerrr-deadzone (5)
2. When the absolute value of the yaw rate deviation Yerrr is greater than or equal to the dead zone deadzone (step 506) and the yaw rate deviation Yerrr is a negative value (step 507); control is performed by calculating the dead zone processing shown in the following equation (6) The yaw rate deviation X is calculated (step 510).
X = Yerrr + deadzone (6)
3. When the absolute value of the yaw rate deviation Yerrr is smaller than the dead zone deadzone (step 506); 0 is substituted into the control yaw rate deviation X (step 508).

Next, the ECU 30 proceeds to step 511 and acquires the vehicle turning state control amount VF based on the control yaw rate deviation X. Specifically, the ECU 30 stores the table (map) shown in FIG. 4 that defines the relationship between the control yaw rate deviation X and the vehicle turning state control amount VF in a ROM included in the ECU 30 in advance. The vehicle turning state control amount VF is calculated using the control yaw rate deviation X and the table. Next, the ECU 30 proceeds to step 512, and changes the magnitude of the vehicle turning state control amount VF according to the magnitude of the steering angle deviation θerr by performing calculation using the following equation (7).
VF = VF · g (θerr) (7)
As shown in FIG. 5, the function g is a function that decreases the vehicle turning state control amount VF as the steering angle deviation θerr increases.

  Next, the ECU 30 proceeds to step 513, executes vehicle braking control based on the vehicle turning state control amount VF, proceeds to step 514, and once ends this routine. Specifically, the ECU 30 calculates a braking force to be applied to each wheel based on the vehicle turning state control amount VF by a known method, and controls the electromagnetic valve of the hydraulic circuit 22 so that the braking force is applied to each wheel. The brake pressure of each wheel cylinder is controlled by sending a signal.

  By the above processing, the vehicle turning state obtained so as to reduce the magnitude of the deviation between the target yaw rate Yrstd as the target vehicle turning state amount and the actual yaw rate Yr corresponding to the actual vehicle turning state amount is changed. A force corresponding to the vehicle turning state control amount VF is applied to the vehicle. That is, vehicle turning state control (vehicle behavior control) is executed.

  The processing from step 506 to step 513 is a vehicle turning state control for changing the turning state of the vehicle so that the deviation (Yerrr) between the target vehicle turning state amount and the actual vehicle turning state amount is small. The vehicle turning state control means for executing the vehicle turning state control for obtaining the amount VF and executing the vehicle turning state control for applying the force according to the vehicle turning state control amount VF to the vehicle, and the vehicle turning state control means for the vehicle turning state control. Vehicle turning state control amount changing means for changing the vehicle turning state control amount VF to be used based on the tire turning angle deviation equivalent value θerr is configured.

(Dead zone calculation)
The ECU 30 is configured to execute a routine (dead zone calculation routine) for calculating a dead zone deadzone necessary for the vehicle turning state control shown in the flowchart of FIG. 6 at predetermined time intervals. Now, the description will be continued assuming that the vehicle is traveling straight. When the predetermined timing is reached, the ECU 30 starts processing of this routine from step 601 and proceeds to step 602 to proceed to the right front wheel speed Vwfr detected by the right front wheel speed sensor 32FR and the left front wheel detected by the left front wheel speed sensor 32FL. It is determined whether or not the absolute value of the difference from the speed Vwfl is smaller than a predetermined value α. If the vehicle is traveling straight, the absolute value of the difference between the right front wheel speed Vwfr and the left front wheel speed Vwl is smaller than α. Therefore, according to the above assumption, the ECU 30 determines “Yes” in step 602 and proceeds to step 603.

  In step 603, the ECU 30 determines that the absolute value of the difference between the right rear wheel speed Vwrr detected by the right rear wheel speed sensor 32RR and the left rear wheel speed Vwrl detected by the left rear wheel speed sensor 32RL is from a predetermined value β. It is determined whether or not it is small. If the vehicle is running straight, the absolute value of the difference between the right front wheel speed Vwfr and the left front wheel speed Vwl is smaller than β. Therefore, according to the above assumption, the ECU 30 determines “Yes” in step 603 and proceeds to step 604.

  In step 604, the ECU 30 determines whether or not the absolute value of the lateral acceleration Gy detected by the lateral acceleration sensor 40 is smaller than a predetermined value γ. If the vehicle is traveling straight, the absolute value of the lateral acceleration Gy is smaller than γ. Therefore, according to the above assumption, the ECU 30 determines “Yes” in step 604 and proceeds to step 605.

  In step 605, the ECU 30 determines whether or not the absolute value of the actual yaw rate Yr detected by the yaw rate sensor 38 is smaller than a predetermined value ε. If the vehicle is traveling straight, the absolute value of the actual yaw rate Yr is smaller than ε. Therefore, according to the above assumption, the ECU 30 determines “Yes” in step 605 and proceeds to step 606.

  In step 606, the ECU 30 substitutes the steering angle θ detected by the steering angle sensor 34 into the steering angle deviation θerr. This is because, since the vehicle is in a straight traveling state, the steering angle is normally 0 (the design of the steering wheel is at a predetermined neutral position), so the steering angle θ detected by the steering angle sensor 34 is This is based on being equal to the steering angle deviation θerr.

  Next, the ECU 30 proceeds to step 607 to calculate the dead zone deadzone from the steering angle deviation θerr and the function h. The function h is a simple increase function that increases the dead zone deadzone (> 0) as the magnitude of the steering angle deviation θerr (| θerr |) increases (see FIG. 3).

  Next, the ECU 30 proceeds to step 608 and determines whether or not a warning to the driver is necessary by determining whether or not the absolute value of the steering angle deviation θerr is larger than a predetermined warning steering angle θth. If the absolute value of the steering angle deviation θerr is greater than or equal to the warning steering angle θth, the ECU 30 determines that a warning is necessary, proceeds to step 609, turns on the warning lamp 36, and proceeds to step 610 to proceed to this routine. Is temporarily terminated. If the absolute value of the steering angle deviation θerr is less than the warning steering angle θth, the ECU 30 determines that no warning is required, and proceeds directly to step 610 to end the present routine tentatively.

  On the other hand, when the vehicle is not in the straight traveling state, the ECU 30 determines “No” in any of step 602, step 603, step 604, and step 605, and proceeds to step 608 without going through step 606 and step 607. Proceed to Accordingly, the dead zone deadzone is not changed.

  As described above, the vehicle behavior control apparatus 10 according to the embodiment of the present invention reduces the steering angle deviation θerr which is a deviation from the neutral direction of the design of the steering wheel in the straight traveling state corresponding to the tire break angle deviation δerr. Based on this, the dead zone deadzone at the time of vehicle turning state control is calculated, and the vehicle turning state amount VF is calculated taking the dead zone deadzone into consideration. By performing the vehicle behavior control based on the vehicle turning state amount VF, it is possible to prevent the vehicle behavior control (lateral force control) for changing the vehicle turning state at an early stage from being started. Further, by changing the magnitude of the vehicle turning state control amount VF according to the magnitude of the steering angle deviation θerr, it is possible to prevent the moment generated by the vehicle behavior control from increasing.

  The present invention is not limited to the above-described embodiment, and various modifications as described below can be adopted within the scope of the present invention.

  For example, the vehicle behavior control device 10 of the above embodiment is configured to control the braking pressure of each wheel cylinder through the hydraulic circuit 22, but adopts a brake-by-wire system (BBWS), and each wheel cylinder through the electric circuit. The braking pressure may be controlled. Further, when the present invention is applied to a vehicle capable of controlling each wheel driving force such as an in-wheel motor, the vehicle turning control may be performed by changing the driving force of each wheel.

  The vehicle behavior control device 10 of the above embodiment employs a rack-and-pinion type steering device 16 that is driven in response to turning of the steering wheel 14, but a variable gear ratio steering (VGS) system. Or a steering device employing a steering-by-wire system (SBWS). In a vehicle that employs a by-wire system (SBWS), the steering angle θ (operation angle of the steering wheel 14) is equivalent to the steering amount (steering instruction amount) from the steering neutral position.

  In addition, the vehicle behavior control device 10 of the above embodiment calculates the steering angle deviation θerr (and therefore the tire turn angle deviation) when it is determined that the vehicle is in the straight traveling state. When the vehicle is in the state, the steering angle deviation θerr (accordingly, the tire turning angle deviation) may be obtained. In this case, for example, when the vehicle turning state control is not executed, the obtained actual yaw rate Yr is applied to the above equations (1) and (2) instead of the target yaw rate Yrstd, and the obtained vehicle speed By applying V to the equations (1) and (2), the tire turning angle δ is calculated, the estimated steering angle θs is estimated from the tire turning angle δ and the inverse function of the function f, and the estimated The steering angle deviation θerr may be obtained from the deviation between the steering angle θs and the actual steering angle θ.

  Further, in the above embodiment, whether or not the vehicle is in a straight traveling state based on the wheel speed difference between the left and right front wheels, the wheel speed difference between the left and right rear wheels, the lateral acceleration and the yaw rate is determined by the processing from step 602 to step 605. Although it has been determined, it may be determined whether or not the vehicle is traveling straight based on one of these parameters or a combination of any two or more.

  In the above embodiment, the vehicle behavior is controlled based on the steering angle. However, a means (for example, a tire turning angle sensor) for obtaining the tire turning angle of the steered wheel is provided, and the tire obtained by the means. Vehicle behavior control may be performed based on the turning angle. In such a case, the tire turning angle equivalent value is treated as the tire turning angle itself.

It is the schematic of the vehicle behavior control apparatus which concerns on embodiment of this invention. It is the map which showed the relationship between a yaw rate deviation and a vehicle turning state control amount. It is the map which showed the relationship between each deviation with tire running, and vehicle turning state control amount. 2 is a map showing a relationship between a control yaw rate deviation referred to by a CPU of the electric control device shown in FIG. 1 and a vehicle turning state control amount. It is the flowchart which showed the routine which CPU of the electric control apparatus shown in FIG. 1 performs. It is the flowchart which showed the routine which CPU of the electric control apparatus shown in FIG. 1 performs.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Vehicle behavior control apparatus, 11 ... Vehicle, 12R ... Right rear wheel, 12FR ... Right front wheel, 12RL ... Left rear wheel, 12FL ... Left front wheel, 14 ... Steering wheel, 16 ... Steering device, 18R ... Right tie rod, 18L ... Left tie rod, 22 ... hydraulic circuit, 24RR ... right rear wheel cylinder, 24FR ... right front wheel cylinder, 24RL ... left rear wheel cylinder, 24FL ... left front wheel cylinder, 26 ... brake pedal, 28 ... master cylinder, 32RR ... right rear wheel speed Sensor: 32FR: Front right wheel speed sensor, 32RL: Left rear wheel speed sensor, 32FL: Left front wheel speed sensor, 34: Steering angle sensor, 36: Warning light, 38: Yaw rate sensor, 40: Lateral acceleration sensor.

Claims (6)

Control tire cutting angle acquisition means for acquiring a control tire cutting angle corresponding to a difference between a predetermined reference tire cutting angle and an actual tire cutting angle;
Target vehicle turning state amount acquisition means for acquiring a target vehicle turning state amount representing a turning state targeted by the vehicle based on the control tire turning angle;
An actual vehicle turning state amount acquisition means for acquiring an actual vehicle turning state amount that is an actual turning state of the vehicle;
Obtaining a vehicle turning state control amount for changing the turning state of the vehicle so that a deviation between the target vehicle turning state amount and the actual vehicle turning state amount is small, and to the vehicle turning state control amount Vehicle turning state control means for executing vehicle turning state control for applying a corresponding force to the vehicle;
A vehicle behavior control device comprising:
An estimated tire turning angle equivalent value corresponding to a tire turning angle from the front-rear direction of the vehicle based on the acquired actual vehicle turning state amount when the vehicle turning state control by the vehicle turning state control means is not executed. And the actual tire angle corresponding value corresponding to the actual tire angle from the longitudinal direction of the vehicle is acquired, and the difference between the estimated tire angle equivalent value and the actual tire angle equivalent value is obtained. Tire turning angle deviation equivalent value acquiring means for acquiring a tire turning angle deviation equivalent value;
Vehicle turning state control amount changing means for changing the vehicle turning state control amount used by the vehicle turning state control means for the vehicle turning state control based on the acquired tire turning angle deviation equivalent value;
A vehicle behavior control device comprising: The vehicle behavior control apparatus according to claim 1,
The actual vehicle turning state quantity acquisition means includes
The actual vehicle turning state quantity is configured to acquire at least one of an actual yaw rate of the vehicle and an actual lateral acceleration of the vehicle,
The tire turning angle deviation equivalent value acquisition means includes:
It is determined whether the vehicle is in a straight traveling state based on at least one of the acquired yaw rate and the acquired lateral acceleration, and when it is determined that the vehicle is in a straight traveling state, the estimated tire The cut angle equivalent value is estimated to be a value corresponding to the tire cut angle from the front-rear direction of the vehicle when the tire direction coincides with the front-rear direction of the vehicle, and the tire cut angle deviation equivalent A vehicle behavior control device configured to obtain a value. In the vehicle behavior control apparatus according to claim 1 or 2,
The target vehicle turning state quantity acquisition means is
A target yaw rate is acquired as the target vehicle turning state quantity;
The actual vehicle turning state quantity acquisition means includes
An actual yaw rate that is an actual yaw rate of the vehicle is acquired as the actual vehicle turning state quantity;
The vehicle turning state control means includes
The vehicle turning state control amount is acquired when a magnitude of a yaw rate deviation that is a difference between the target yaw rate and the actual yaw rate is equal to or greater than a predetermined threshold;
The vehicle turning state control amount changing means is
A vehicle behavior control device configured to change the vehicle turning state control amount by increasing the predetermined threshold value as the acquired tire turning angle deviation equivalent value increases. In the vehicle behavior control apparatus according to claim 1 or 2,
The target vehicle turning state quantity acquisition means is
A target yaw rate is acquired as the target vehicle turning state quantity;
The actual vehicle turning state quantity acquisition means includes
An actual yaw rate that is an actual yaw rate of the vehicle is acquired as the actual vehicle turning state quantity;
The vehicle turning state control means includes
The vehicle turning state control amount that increases as the magnitude of the yaw rate deviation, which is the difference between the target yaw rate and the actual yaw rate, increases based on the yaw rate deviation,
The vehicle turning state control amount changing means is
A vehicle behavior control device configured to decrease the magnitude of the vehicle turning state control amount as the acquired tire turning angle deviation equivalent value increases. In the vehicle behavior control apparatus according to claim 1 or 2,
The target vehicle turning state quantity acquisition means is
A target yaw rate is acquired as the target vehicle turning state quantity;
The actual vehicle turning state quantity acquisition means includes
An actual yaw rate that is an actual yaw rate of the vehicle is acquired as the actual vehicle turning state quantity;
The vehicle turning state control means includes
Based on the yaw rate deviation that is the difference between the target yaw rate and the actual yaw rate, the vehicle turning state control amount is acquired such that the magnitude of the vehicle turning state control amount increases as the magnitude of the yaw rate deviation increases. Composed of
The vehicle turning state control amount changing means is
The vehicle turning state is reduced by reducing the magnitude of the yaw rate deviation used for acquiring the vehicle turning state control amount in the vehicle turning state control as the acquired value corresponding to the tire turning angle deviation increases. A vehicle behavior control device configured to change a control amount. In the vehicle behavior control apparatus according to claim 2,
The tire turning angle deviation equivalent value acquisition means includes:
A vehicle behavior control device configured to acquire a steering angle from a neutral position of a steering wheel of the vehicle when it is determined that the vehicle is in a straight traveling state as a value corresponding to a tire turning angle deviation.

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