JP4853068B2 - Vehicle support control device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a support control device for a vehicle capable of speedily changing it over to emergency avoiding control from control by a driver taking an obstruction avoiding action when it is judged that emergency avoidance is necessary while reflecting an intention of the obstruction avoiding action of the driver. <P>SOLUTION: This support control device for the vehicle is furnished with a normal time vehicle steering means 10D to drive a steering system of the vehicle in correspondence with steering quantity of the driver in avoidance operation of an obstruction and an emergent time obstruction avoiding means 6 to carry out obstruction avoiding control while reflecting the obstruction avoiding action of the driver as an emergent event in judging that avoidance of the obstruction is impossible in accordance with the avoiding control by the normal time vehicle steering means 10D in accordance with a position of the obstruction and a travelling state of the driver's own vehicle. <P>COPYRIGHT: (C)2008,JPO&amp;INPIT

Description

  The present invention relates to a vehicle support control apparatus that can support obstacle avoidance.

  Conventionally, a vehicle support control apparatus that avoids an obstacle automatically detects that the obstacle cannot be avoided only by a braking operation for the purpose of appropriately executing the obstacle avoidance traveling. The thing of the structure which transfers the vehicle control mode of a vehicle to avoidance driving mode is known.

In this conventional system, the first mode in which the control characteristics are changed in a direction in which the avoidance traveling mode improves the turning performance more than usual, and the second mode in which the control characteristics are changed in a direction in which the vehicle posture is maintained stronger than the first mode By switching to the second mode when the steering direction of the steering wheel is reversed during the execution of the first mode, obstacle avoidance is appropriately performed in consideration of from before avoidance to after avoidance. (See Patent Document 1).
JP 2000-302057 A

  However, in the device disclosed in Japanese Patent Laid-Open No. 2000-302057, the control mode is switched from emphasizing turning ability to emphasizing vehicle posture stability after detecting reversal of the steering direction of the driver's steering wheel. Since it is not configured to use the surrounding information of the vehicle when switching modes, there remains a problem that the switching timing may not be suitable for achieving both obstacle avoidance and off-road departure prevention. ing.

  For example, if the driver's steering wheel is excessive, switching from emphasis on turning performance to stability with reversal of the steering operation of the driver will cause the timing to be too late and the vehicle yaw angle will already be more than necessary at the time of switching. Even if the obstacle avoidance is successful, there is a risk that the vehicle will deviate from the road after avoiding the obstacle, and it is difficult to say that the control structure fully considers this risk.

  The present invention was made in view of the above circumstances, and reflects the driver's obstacle avoidance behavior when it is determined that emergency avoidance is necessary while reflecting the intention of the driver's obstacle avoidance behavior. It is an object of the present invention to provide a vehicle support control device capable of quickly switching from control to emergency avoidance control.

The vehicle support control device according to claim 1 includes a front situation detection means for detecting a road situation in front of the host vehicle including an obstacle located in front of the host vehicle and a road boundary in front of the host vehicle, and traveling of the host vehicle. A vehicle traveling state detecting means for detecting a state; a steering amount detecting means for detecting a steering amount of the driver; a normal vehicle steering means for driving a steering system of the vehicle according to the steering amount of the driver; Emergency obstacle avoidance means for issuing an obstacle avoidance command when it is determined that the obstacle cannot be avoided by the avoidance control by the vehicle steering means of the driver at a normal time,
The emergency obstacle avoidance means is based on the normal vehicle steering means based on the position of the obstacle detected by the forward situation detection means and the running state of the host vehicle detected by the own vehicle running state detection means. The emergency support necessity determination means for determining whether or not the obstacle can be avoided by avoidance control, and a predetermined time from the current time when it is determined that emergency support is required based on the emergency support necessity determination means A driver steering prediction means for calculating a time series of steering expected to be executed by the driver by an elapsed time after the elapse of time, and the emergency support necessity determination means when the emergency support is determined to be necessary Assistance control amount calculation means for calculating an emergency assistance control amount for avoiding obstacles, and wheels in an emergency based on the emergency assistance control amount obtained by the assistance control amount calculation means And a Kyuji wheel control means,
The assist control amount calculation means includes vehicle motion prediction means for predicting vehicle motion at the time of emergency support based on a time series of steering by the driver steering prediction means, and from the current time to an elapsed time after elapse of a predetermined time. A state evaluation function generating means for generating a state evaluation function for evaluating an obstacle avoidance risk state provided from a relationship between the prediction result of the vehicle motion between the vehicle and the obstacle, and the normal vehicle steering means. Calculation means for calculating the emergency assistance control amount based on the state evaluation function so that the avoidance risk state of the vehicle travel locus determined by working is appropriate,
The driver steering prediction means has a plurality of predetermined steering patterns, and steers from the plurality of steering patterns based on the steering amount at the current time and the steering speed of the driver at the current time. A driver steering prediction time series is generated by selecting a pattern.
The vehicle support control device according to claim 2 includes a front situation detection means for detecting a road situation in front of the host vehicle including an obstacle located in front of the host vehicle and a road boundary in front of the host vehicle, and traveling of the host vehicle. A vehicle traveling state detecting means for detecting a state; a steering amount detecting means for detecting a steering amount of the driver; a normal vehicle steering means for driving a steering system of the vehicle according to the steering amount of the driver; Emergency obstacle avoidance means for issuing an obstacle avoidance command when it is determined that the obstacle cannot be avoided by the avoidance control by the vehicle steering means of the driver at a normal time,
The emergency obstacle avoidance means is based on the normal vehicle steering means based on the position of the obstacle detected by the forward situation detection means and the running state of the host vehicle detected by the own vehicle running state detection means. The emergency support necessity determination means for determining whether or not the obstacle can be avoided by avoidance control, and a predetermined time from the current time when it is determined that emergency support is required based on the emergency support necessity determination means A driver steering prediction means for calculating a time series of steering expected to be executed by the driver by an elapsed time after the elapse of time, and the emergency support necessity determination means when the emergency support is determined to be necessary Assistance control amount calculation means for calculating an emergency assistance control amount for avoiding obstacles, and wheels in an emergency based on the emergency assistance control amount obtained by the assistance control amount calculation means And a Kyuji wheel control means,
The assist control amount calculation means includes vehicle motion prediction means for predicting vehicle motion at the time of emergency support based on a time series of steering by the driver steering prediction means, and from the current time to an elapsed time after elapse of a predetermined time. A state evaluation function generating means for generating a state evaluation function for evaluating an obstacle avoidance risk state provided from a relationship between the prediction result of the vehicle motion between the vehicle and the obstacle, and the normal vehicle steering means. Calculation means for calculating the emergency assistance control amount based on the state evaluation function so that the avoidance risk state of the vehicle travel locus determined by working is appropriate,
The driver steering prediction means includes state evaluation function generation means for generating a state evaluation function for evaluating a state of vehicle motion generated as a result of steering applied between the current time and after a predetermined time has elapsed. It is characterized by that.

The vehicle support control apparatus according to claim 3 , wherein the emergency obstacle avoidance means includes obstacle movement trajectory prediction means for predicting a movement trajectory of the obstacle, and the state evaluation function is the movement of the obstacle. The emergency support control amount includes a trajectory, and is determined in consideration of the movement trajectory of the obstacle.

The vehicle support control apparatus according to claim 4 , wherein the normal vehicle steering means is configured to steer front wheels in proportion to a steering amount of the driver, and the emergency wheel control means includes left and right rear wheels. It is characterized by a structure for steering wheels.

The vehicle support control apparatus according to claim 5 , wherein the normal vehicle steering means is configured to steer front wheels in proportion to a steering amount of the driver, and the emergency wheel control means includes right and left wheels. The structure is such that the rear wheel is controlled based on the difference in braking force between the rear wheels.

The vehicle support control apparatus according to claim 6 , wherein the normal-time vehicle steering means is configured to steer front wheels in proportion to a steering amount of the driver, and the emergency wheel control means is the normal time The structure is characterized in that a correction is made to the steering angle corresponding to the steering amount of the vehicle steering means.

The vehicle support control device according to claim 7 , wherein the normal vehicle steering means steers the front wheels in proportion to the steering amount of the driver and also the difference in the steering amount of the rear wheels or the braking force of the rear wheels. The emergency wheel control means has a structure for steering the left and right rear wheels or a structure for controlling the rear wheels based on a difference in braking force between the left and right rear wheels.

The vehicle support control apparatus according to claim 8 , wherein the emergency support necessity determination means includes a relative position between the host vehicle and an obstacle existing ahead of the host vehicle, and a relative position of the obstacle with respect to the host vehicle. The emergency support is started when the speed, the steering amount of the driver, and the steering speed of the driver satisfy predetermined conditions.

The vehicle support control apparatus according to claim 9 , wherein the emergency support necessity determination unit is configured such that a distance between the vehicle and the obstacle is equal to or less than a predetermined value when the vehicle is driven according to the driver steering prediction time series. Emergency support is started when the distance between the vehicle and the road boundary is a predetermined value or less.

The vehicle support control device according to claim 10 , after starting emergency support, repeatedly calculates the support control amount at predetermined time intervals, updates the support control amount, and sets the updated support control amount as a target value. It is characterized by providing support.

According to the first and second aspects of the invention, when the avoidance behavior based on the driver's steering cannot be avoided, the intention of the driver's avoidance behavior is reflected and the normal control is changed to the emergency time. There is an effect that switching to control can be performed quickly.
In particular, according to the first aspect of the present invention, the driver steering prediction time series is generated by selecting a steering pattern from a plurality of predetermined steering patterns and generating the driver steering prediction time series. It can be generated easily.
According to the second aspect of the present invention, the driver's steering pattern is predicted, and it is determined whether or not emergency assistance is started based on the case where the avoidance operation is performed only by the driver's steering operation. Therefore, the emergency support control is executed only in a situation where the emergency support control is actually necessary, and it is possible to prevent unnecessary intervention from being performed on the driver's operation.

  In this case, if the emergency support control amount is determined in consideration of the obstacle and the road boundary, the vehicle movement is more detailed when avoiding the obstacle compared to the method of switching the control characteristics of the vehicle. realizable.

According to the third aspect of the present invention, since the emergency assistance control amount can be determined by predicting the movement locus of the obstacle, there is an effect that appropriate avoidance assistance control can be realized even for the moving obstacle.

According to the fourth and fifth aspects of the present invention, the rear wheel is controlled only in an emergency to avoid obstacles, so that it does not change during normal travel and normal avoidance operation. It is possible to avoid obstacles in an emergency while maintaining a driving feeling.

According to the invention described in claim 6 , since the structure is such that the steering angle of the front wheels steered by the driver is corrected in an emergency, wheel control during emergency support can be performed only with the front wheels, and emergency support is provided. There is an effect that the control device can be manufactured at a lower cost than that of a structure that performs control by rear wheel control.

According to the invention described in claim 7 , since the rear wheel steering or the difference between the left and right driving force differences can be controlled in the normal time separately from the emergency control, the obstacle avoidance performance in the emergency can be improved. And an improvement in drivability during normal operation can be achieved.

According to the eighth aspect of the present invention, the necessity of emergency avoidance assistance is determined based on the degree of approach to the obstacle and the driver's steering operation, so the risk of contact with the obstacle of the driver is determined. The emergency avoidance support can be started in response to the recognition of the driver, and the driver can feel less discomfort in the steering operation due to the start of the avoidance support control.

According to the ninth aspect of the present invention, the necessity of emergency avoidance support control is determined based on the degree of approach between the predicted travel path of the host vehicle by the driver's steering and the obstacle or the road boundary. It is possible to accurately consider the risk of contact with an object and deviation from the road, and unnecessary emergency avoidance support control can be suppressed.

According to the invention described in claim 10 , since the emergency support control amount is updated every predetermined time interval, the prediction of uncertain elements such as the driver's steering pattern and obstacle movement trajectory is performed. Even when a deviation occurs between the behavior of the previous prediction and the current vehicle, it is possible to promptly execute appropriate emergency support control based on the new prediction.

  Embodiments of the present invention will be described below with reference to the drawings.

  1 to 11 are diagrams for explaining a vehicle support control apparatus according to a first embodiment of the present invention.

  FIG. 1 is a layout diagram of components necessary for the vehicle support control apparatus according to the first embodiment.

  In FIG. 1, 1 is a camera, 2 is a vehicle speed sensor, 3 is a yaw rate sensor, 4 is an acceleration sensor, 5 is a steering angle sensor, 6 is a microprocessor, 7 is a rear wheel steering controller, 8 is a rear wheel steering angle sensor, Reference numeral 9 denotes a rear wheel steering motor. Each of these components is arranged at an appropriate location of the vehicle 10 as described below.

  The camera 1 is mounted in front of the vehicle interior, photographs the road conditions ahead of the vehicle, and detects the road conditions ahead of the vehicle including obstacles, road boundaries, white lines, etc. 2). Here, the camera 1 is provided with a pair in the vehicle width direction of the vehicle 10 so as to detect the direction and distance of the obstacle.

  Here, a rotary encoder attached to a wheel of a wheel (not shown) is used as the vehicle speed sensor 2, and the vehicle speed is measured by detecting a pulse signal generated in proportion to the rotation of the wheel.

  The yaw rate sensor 3 is provided at the center of the vehicle 10 and a known device using a crystal resonator or a semiconductor is used. The yaw rate sensor 3 detects the yaw rate generated in the vehicle 10.

  The acceleration sensor 4 is provided at an appropriate location, and a known device using a piezoelectric element or the like is used. The acceleration sensor 4 is used to detect acceleration in a specific direction generated in the vehicle 10. Here, it is assumed that the acceleration generated in the lateral direction of the vehicle 10 is detected. The vehicle speed sensor 2, the yaw rate sensor 3, and the acceleration sensor 4 function as own vehicle running state detection means 10B that detects the running state of the own vehicle. The camera 1 is also used as a part of the vehicle running state detection means 10B.

  The steering angle sensor 5 is provided on the steering shaft 5A, and is used to measure the rotation angle of the steering wheel 5B by the driver's steering by detecting the rotation angle of the gear in the steering shaft 5A. The steering angle sensor 5 functions as a steering amount detection means 10C that detects the steering amount of the driver.

  The microprocessor 6 is an integrated circuit including an A / D conversion circuit, a D / A conversion circuit, a central processing unit, a memory, and the like, and is provided at an appropriate place.

  The microprocessor 6 processes the signals detected by the sensors 2 to 5 and calculates an emergency support control amount for emergency avoidance support according to a program stored in the memory, and outputs the result to the rear wheel steering controller 7. Output to.

  The microprocessor 6 functions as an emergency obstacle avoiding means for issuing an obstacle avoidance command when it is determined that the obstacle cannot be avoided by the avoidance control by the normal vehicle steering means 10D. The obstacle avoidance by the avoidance control by the normal vehicle steering means 10D based on the position of the obstacle detected by the forward situation detection means 10A and the running state of the own vehicle detected by the own vehicle running condition detection means 10B. 6A for determining the necessity of emergency support for determining whether or not it is possible and from the current time when emergency support is determined based on the means for determining emergency support 6A to the elapsed time after a predetermined time has elapsed The driver steering predicting means 6B for calculating the time series of steering expected to be executed by the driver and the emergency support necessity determining means 6A Assistance is in charge of functions as assist control amount calculating means 6C that calculates the emergency assistance control amount for performing obstacle avoidance when it is determined to be necessary. Details of each means will be described later.

  The rear wheel steering controller 7 includes a microprocessor for performing a control calculation and a booster circuit for driving the rear wheel steering motor 9. The rear wheel steering controller 7 executes target servo control based on rear wheel steering angle information that is an emergency assistance control amount output from the microprocessor 6.

  The rear wheel steering angle sensor 8 measures the value of the steering angle by detecting the rack stroke amount in the rack-and-pinion type rear wheel steering mechanism, and measures it toward the rear wheel steering controller 7 as a feedback signal during servo control. Output the value. The rear wheel steering motor 9 plays a role of automatically driving the steering mechanism 9C of the rear wheel 9D by rotating the pinion gear. The rear wheel steering controller 7, the rear wheel steering angle sensor 8, and the rear wheel steering motor 9 are disposed at appropriate positions at the rear of the vehicle. The rear wheel steering controller 7, the rear wheel steering angle sensor 8, and the rear wheel steering motor 9 Serves as the emergency wheel control means 10E for controlling the rear wheel 9D in an emergency based on the emergency support control quantity obtained by the support control quantity calculation means 6C.

  FIG. 2 is a block diagram in which these components are collectively expressed in blocks from the functional aspect.

  The steering wheel 5B and the front wheel steering mechanism 5C are mechanically connected via a gear, and the front wheels 5D and 5D are steered according to the rotation angle of the steering wheel 5B. The steering system that controls the front wheels 5D including the steering wheel 5B and the front wheel steering mechanism 5C constitutes the above-described normal-time vehicle steering means 10E.

  In calculating the emergency avoidance assistance control amount, information indicating the vehicle's movement state, specifically information such as the vehicle's position, speed, attitude angle, yaw rate, lateral acceleration, etc. is required. The information obtained by the camera 1, the vehicle speed sensor 2, the yaw rate sensor 3, and the acceleration sensor 4 is obtained by integrated processing.

  Further, information related to the driver's steering input is also required, and can be obtained by measuring the driver's steering input using the steering angle sensor 5 described above.

  Furthermore, information on the motion state of the obstacle and the position of the road boundary is also required, and these can be obtained by performing image processing on the image captured by the camera 1 and extracting information on the obstacle and the road boundary. Since many known techniques are known for detecting obstacles and road boundaries by image processing, the description of the specific method is omitted here.

  In addition to the signal processing of each sensor 2-5, the microprocessor 6 plays a role of calculating the emergency support control amount as described above. The emergency support necessity determination means 6A, the driver steering prediction means 6B, and the assistance control amount calculation means 6C shown in FIG. 2 of the microprocessor 6 are composed of software module groups and share the necessary functions for processing. Yes.

  Based on the measured steering angle signal, the driver steering prediction means 6B is expected to be executed in the future from the current time when the driver determines that emergency support is required by the emergency support necessity determination means 6A. Calculate the time series of steering.

  When the obstacle detected by the camera 1 is moving, the obstacle movement locus prediction means 6D predicts the obstacle movement locus.

  The emergency support necessity determination means 6A determines that the assistance control is necessary when the risk of contact between the host vehicle and the obstacle is high and the driver is performing steering for avoidance. The process of the control amount calculation means 6C is executed.

  The assist control amount calculation means 6C calculates the most convenient steering pattern for the host vehicle in order to steer the rear wheel 9D that can be controlled independently of the driver's steering from the current time to the future after a predetermined time has elapsed. To do.

  The support control amount calculation means 6C executes the vehicle motion prediction means 6E that predicts the motion state of the vehicle at the time of emergency support based on the time series of the steering of the front wheels 5D and the steering of the rear wheels 9D, and a certain steering pattern. State evaluation function generating means 6F for generating a state evaluation function for numerically evaluating the degree of appropriateness of the predicted movement state of the vehicle in light of the objectives of avoiding obstacles and preventing off-road departure and emergency support And a calculation means 6G for calculating the control amount.

  The vehicle motion prediction means 6E and the state evaluation function generation means 6F are also composed of software modules, and details thereof will be described later.

  The rear wheel 9D steering amount time series calculated by the assist control amount calculation means 6C is sequentially sent to the rear wheel steering controller 7 as a steering command value. The rear wheel steering controller 7 executes servo control for the steering command value by driving the rear wheel steering motor 9 based on the steering command value from the microprocessor 6. Since the steering servo system can be constructed by using a known technique, the description thereof is omitted here.

  Hereinafter, the calculation procedure of the emergency assistance control amount of the microprocessor 6 will be described based on the processing flowchart of the microprocessor 6 shown in FIG. In addition, in order to make the explanation concrete, in this embodiment, the processing contents are explained assuming the scene shown in FIG.

  FIG. 3 shows that when the host vehicle NS is traveling on the straight road RO, a pedestrian as an obstacle WO starts to cross from the left side of the front road of the host vehicle NS and jumps out on the forward path of the host vehicle NS. Is assumed. The straight road RO of the own vehicle NS is partitioned on both sides by a partition wall WA, and it is physically impossible to deviate from the road.

  As shown in FIG. 20, the microprocessor 6 reads the detection signals of the camera 1 and the sensors 2 to 5, processes the read signals, and converts them into information useful for calculating the support control amount (S.1). ).

  FIG. 3 is a processing flowchart showing details of processing contents of No. 1;

  As shown in FIG. 21, the image including the front road situation imaged by the camera 1 and the signals detected by the sensors 2 to 5 are stored in a predetermined memory area of the microprocessor 6 (S.11).

  The microprocessor 6 processes the image captured by the camera 1 to detect the road boundaries ROR and ROL, and calculates the distances LL and LR between the host vehicle NS and the right road boundary ROR and the left road boundary ROL (S. 12).

  The microprocessor 6 sets a coordinate system for describing the movement of the host vehicle NS and the obstacle WO. In this embodiment, as shown in FIG. 4, the X axis is set along the traveling direction of the straight road RO, and the Y axis is set in a direction orthogonal to the X axis (S.13).

The coordinate origin O can be arbitrarily selected. For example, the position of the center of gravity of the vehicle NS at the current time can be set as the X coordinate origin, and the Y coordinate origin can be set near the center line of the road. By setting the coordinate system, the positions of the host vehicle NS, the obstacle WO, the road boundary ROR, and the ROL can be expressed by coordinate values. Here, the road boundaries ROR and ROL are described as Y = y _R and Y = y _L , respectively.

  The microprocessor 6 processes the image captured by the camera 1 to detect the obstacle WO, and calculates the position of the obstacle WO. The relative position between the host vehicle NS and the obstacle WO directly calculated by the image processing is converted into a set coordinate system value and recorded in a predetermined memory area.

Here, the position of the obstacle WO is described as (X, Y) = (x _P , y _P ). If the obstacle WO has already been detected in the previous control cycle, the moving speed of the obstacle WO is obtained by taking the difference between the position of the previous obstacle WO and the position of the obstacle WO at the current time. Is also calculated and recorded in a predetermined memory area. The X component and Y component of the moving speed of the obstacle WO are respectively described as (v _p ^x , v _p ^y ) (S.14).

  Next, the microprocessor 6 calculates the value of the vehicle motion state amount necessary for motion prediction of the host vehicle NS. As the vehicle motion state quantity, first, the position of the host vehicle NS is mentioned. The value of the position of the host vehicle NS is automatically determined when the coordinate system is introduced. Here, the position of the host vehicle NS is described as (X, Y) = (x, y). State quantities necessary to describe the vehicle motion state include a vehicle yaw angle θ, a traveling speed v, a slip angle β, and a yaw rate γ. Of these, for the traveling speed v, the vehicle speed is approximated by the wheel speed of the non-driven wheels, assuming that the speed component in the vehicle width direction is sufficiently smaller than the speed component in the vehicle longitudinal direction.

The yaw rate γ can be obtained from the yaw rate sensor 3. Here, since the road is the straight road RO, the vehicle yaw angle θ can be obtained by estimating the angle formed by the road boundaries ROR, ROL and the direction in which the host vehicle NS is facing by image processing. Alternatively, it may be calculated by determining an appropriate initial value and integrating the output value of the yaw rate sensor 3. The slip angle β can be calculated by the following equation (1), describing the vehicle longitudinal speed as v _x and the vehicle width direction as v _y (S.15).

ここで、車両前後方向の速度ｖ_xを走行速度ｖによって近似し、車幅方向の速度ｖ_yを加速度センサ４の出力を積分することによって求めれば、（１）式からすべり角βの近似値が得られる。

Here, the longitudinal direction of the vehicle velocity v _x approximated by the running speed v, be determined by the velocity v _y of the vehicle width direction integrating the output of the acceleration sensor 4, (1) the approximate value of the slip angle β from equation Is obtained.

  In addition, a known technique for estimating the slip angle β more accurately by using an observer for signals such as wheel speed, yaw rate, and acceleration in the vehicle width direction (lateral acceleration) is also known. May be used to obtain the slip angle β.

  Next, the microprocessor 6 calculates the value of the rotational angular velocity of the steering wheel 5B by taking the difference between the detected value of the steering angle sensor 5 and the detected value of the steering angle sensor 5 in the previous control cycle (S). .16).

  Next, the microprocessor 2 determines whether the support control is necessary (S.2). In this embodiment, the avoidance risk between the host vehicle NS and the obstacle WO is evaluated from the relative motion state between the host vehicle NS and the obstacle WO. Specifically, the height of the avoidance risk is determined by the following conditional expression.

更に、運転者が回避操舵を行ったか否かを次式で判定する。

Further, it is determined by the following formula whether or not the driver has performed avoidance steering.

ただし、ＴＴＣ₀、Ｙ₀、ω₀は判定のための閾値を表すパラメータである。（２）、（３）、（４）式が全て成立した場合に支援制御が必要であると判定を下す。

However, TTC ₀ , Y ₀ and ω ₀ are parameters representing threshold values for determination. When all the expressions (2), (3), and (4) are satisfied, it is determined that the assistance control is necessary.

  If it is determined that the assistance control is not necessary, the process is terminated. If it is determined that the assistance control is necessary, S.I. The process proceeds to 3.

  Estimate the future movement trajectory of the obstacle WO. As described above, the position of the obstacle WO can be determined by image processing. As for the estimation of the movement trajectory, as a simple method, for example, the movement speed of the obstacle WO is estimated from the detection history of the obstacle WO, and the uniform linear motion is performed while maintaining the movement speed estimated by the obstacle WO. The movement trajectory can be calculated based on the assumption. That is, the estimated value of the position of the obstacle WO at time t is calculated by the following equation (S.3).

なお、障害物ＷＯが静止していると判定したときには、障害物ＷＯの位置は時刻によって変化しないので、Ｓ．３の処理をスキップしてもよい。

When it is determined that the obstacle WO is stationary, the position of the obstacle WO does not change depending on the time. Step 3 may be skipped.

  The microprocessor 6 then predicts the driver's steering pattern (S.4). Here, it is assumed that steering for avoidance is performed by the basic pattern FDP shown in FIG. 5, and the shape of a specific steering pattern is a function based on the basic pattern FDP according to the actual steering operation of the driver. To be determined.

  The basic pattern shown in FIG. 5 is divided into eight sections. Each section is DB1: before operation, DB2: steering in the avoidance direction, DB3: holding the steering angle, DB4: returning to the neutral position, DB5: steering in the reverse direction. , DB6: Steering angle maintenance, DB7: Return operation to neutral position, DB8: Steering wheel (steering wheel) operation state of operation completion.

Here, as parameters necessary to determine a specific steering pattern shape using a function, there are a steering angular velocity κ, a steering angular amplitude θ _ms , and a switching time T ₁ .

Among these, the steering angular velocity κ is defined as the steering angular velocity at time t ₀ when the support control necessity is determined, ω _s (t ₀ ),

を用いる。

Is used.

For the steering angle amplitude θ _ms , an appropriate value is used based on an angle range in which the driver can operate without changing the steering wheel (steering wheel 5B).

The switching time T ₁ is set on the assumption that the driver performs an operation to return the steering wheel 5B to the neutral position when the driver passes right next to the obstacle WO. In the scene of FIG. 3, assuming that the host vehicle NS is traveling at a substantially constant speed,

を用いる。

Is used.

That is, the microprocessor 6 determines that the steering angle θs of the steering wheel 5B is θs (t ₀ ) in the section DV2, as shown in FIG. 6, from the steering patterns set using the expressions (7) and (8). The time interval of the predetermined prediction interval length T is cut out with the time point t ₀ when the vehicle becomes t as the base point, and the steering pattern is determined as the driver steering prediction time series.

  In the above description, the steering angle θs at the start of steering is

の範囲内にあるものとして説明したが、操舵開始時におけるステアリング角度θｓが上記（９）式の範囲を超えている場合、ハンドルの持ち替えが行われていると仮定して、その時点でのステアリング角度θｓを中心として操舵角振幅＋θ_ms、−θ_msの範囲に操舵パターン予測値のとりうる範囲を設定する。すなわち、

However, if the steering angle θs at the start of steering exceeds the range of the above formula (9), it is assumed that the steering wheel has been changed, and the steering at that time A range where the steering pattern prediction value can be set is set in a range of steering angle amplitudes + θ _ms and −θ _{ms with} the angle θs as a center. That is,

で表される範囲に操舵予測時系列を生成する。

A steering prediction time series is generated in the range represented by

  Further, within the range of the expression (9), it may be considered that the straight line set in the section DV2 directly shifts to the straight line set in the section DV4 in some cases, but in this case, the section DV3 is not set, A pattern that directly transitions from the section DV2 to the section DV4 is generated. Correspondingly, the section DV6 disappears, and a pattern is generated in which the section DV5 transitions directly to the section DV7.

  In addition, as the prediction section length T, it is desirable to set so that the prediction considering the motion after avoiding the obstacle WO can be performed.

という設定が考えられる。

The setting can be considered.

  Thus, step S. of the microprocessor 6 is completed. The description of the content of the process 4 is finished.

  The microprocessor 6 then calculates a support control amount (S.5). As described above, the support control amount calculation unit 6C illustrated in FIG. 2 includes the vehicle motion prediction unit 6E and the state evaluation function generation unit 6F that generates a state evaluation function.

  The vehicle motion prediction means 6E performs prediction of vehicle motion predicted as a result when a specific operation pattern is determined based on the vehicle model. Although various models can be used as the vehicle model, in this embodiment, motion prediction is performed based on a two-wheel model that approximates the motion of a four-wheel vehicle to the motion of a two-wheel vehicle.

  Assuming that the vehicle speed is constant, the two-wheel model is described by the following differential equation:

ただし、ｍ、Ｉ、ｌ_f、ｌ_rはそれぞれ車両質量、車両ヨー慣性モーメント、車両重心から前輪軸までの距離、車両重心から後輪軸までの距離を表す。Ｙ_f、Ｙ_rはタイヤ横力をあらわす関数であり、それぞれ、前輪すべり角β_f、後輪すべり角β_rの関数であると仮定している。

Here, m, I, l _f and l _r represent the vehicle mass, the vehicle yaw moment of inertia, the distance from the vehicle center of gravity to the front wheel axis, and the distance from the vehicle center of gravity to the rear wheel axis, respectively. Y _f and Y _r are functions representing the tire lateral force, and are assumed to be functions of the front wheel slip angle β _f and the rear wheel slip angle β _r , respectively.

A specific example of the shape of the function of the tire lateral forces Y _f and Y _r is shown in FIG. The front wheel slip angle β _f and the rear wheel slip angle β _r can be calculated using the following equations.

ここで、δ_f、δ_rはそれぞれ前輪舵角と後輪舵角とを示す記号である。

Here, δ _f and δ _r are symbols indicating the front wheel steering angle and the rear wheel steering angle, respectively.

  When using the above model, the state vector representing the motion state of the vehicle is

という６次元のベクトルとなる。また、車両に対する操作入力としては前輪舵角δ_fと後輪舵角δ_rの二つがあるので、入力ベクトルは、

This is a 6-dimensional vector. Also, since there are two front wheel steering angle δ _f and rear wheel steering angle δ _r as the operation input to the vehicle, the input vector is

という２次元のベクトルとなる。（１１）式から（１７）式で表現されるモデルは、舵角δを入力とする非線形微分方程式であり、車両運動モデルの右辺をまとめてベクトル値関数と表記すれば、

This is a two-dimensional vector. The models expressed by the equations (11) to (17) are nonlinear differential equations with the steering angle δ as an input, and if the right side of the vehicle motion model is collectively expressed as a vector value function,

という一般的な表現式で表すことができる。入力ベクトルのうち、前輪舵角δ_fについては、運転者のステアリング操作と１対１に対応しており、ステップＳ．４で生成された運転者操舵予測時系列と関連付けられる。ステアリング角度θ_sから前輪舵角δ_fまでのトータルのギア比をＫ_fとすれば、

It can be expressed by a general expression. Among the input vectors, the front wheel steering angle δ _f has a one-to-one correspondence with the steering operation of the driver. 4 is associated with the driver steering prediction time series generated in step 4. _If the total gear ratio from the steering angle θ _s to the front wheel steering angle δ _f is K _f ,

によって、前輪舵角δ_fは決定される。従って、実質的には（２１）式の入力は、後輪舵角δ_rの一つだけである。

Thus, the front wheel steering angle δ _f is determined. Accordingly, the input of the equation (21) is substantially only one of the rear wheel steering angles δ _r .

  The evaluation function is generated using a function of the following equation based on the predicted value of the vehicle state vector with respect to the rear wheel steering angle operation amount applied to the vehicle from the current time until a predetermined time has elapsed.

ただし、Ｌは現在時刻ｔ₀から経過時刻ｔ₀＋Ｔまでの間の各時刻における車両運動状態および操作量の望ましさを評価する評価式、τは現在時刻ｔ₀から経過時刻ｔ₀＋Ｔまで変化する積分変数である。

However, L is an evaluation formula for evaluating the desirability of the vehicle motion state, and the operation amount at each time between the current time t ₀ until the elapsed time t ₀ + T, tau is changed from the present time t ₀ until the elapsed time t ₀ + T Is an integral variable.

  By using the state evaluation function J shown in the equation (24), it is possible to calculate not only the current traveling state of the vehicle but also the operation amount that predicts the future vehicle state.

The evaluation formula L is created by combining these request items, reflecting the following request items.
"1. Do not get too close to the obstacle WO; 2. Do not get too close to the road boundary ROR, ROL; 3. Do not cut the rear wheel steering angle δ _r too much"
The request item 1 is described using a function that increases as the distance between the host vehicle NS and the obstacle WO decreases. Specifically, for example, a function of the following formula is used.

ただし、σ_x、σ_yは関数の形状を決めるパラメータであり、ここでは、それぞれ検出された障害物ＷＯのｘ軸方向の幅、ｙ軸方向の幅に応じた値が設定される。奥行き方向であるｘ軸方向の情報が得られない場合には、σ_x＝σ_yと設定する。障害物ＷＯの位置ｘ_p、ｙ_pには、ステップＳ．３において算出された障害物ＷＯの移動軌跡の値が用いられる。

However, σ _x and σ _y are parameters that determine the shape of the function. Here, values corresponding to the detected width of the obstacle WO in the x-axis direction and the width in the y-axis direction are set. When information in the x-axis direction that is the depth direction cannot be obtained, σ _x = σ _y is set. The position x _p , y _p of the obstacle WO has a step S.P. The value of the movement trajectory of the obstacle WO calculated in 3 is used.

  The request item 2 is described using a function that increases as the distance between the vehicle NS and the road boundaries ROR and ROL decreases. Specifically, for example, a function of the following formula is used.

ただし、Δは道路境界ＲＯＲ、ＲＯＬへの接近の余裕幅を指定するパラメータであり、Δの値が大きいほど、道路境界ＲＯＲ、ＲＯＬとの接近余裕を大きくとる回避経路が算出される。

However, Δ is a parameter for designating the margin of approach to the road boundaries ROR and ROL. The larger the value of Δ, the larger the avoidance route that takes the approach margin to the road boundaries ROR and ROL.

The evaluation formula L _P and the evaluation formula L _R define the risk potential reflecting the avoidance risk for the obstacle WO and the road boundaries ROR and ROW on the straight road RO.

FIG. 8 shows a diagram in which the state evaluation function J obtained by adding the evaluation formula L _P and the evaluation formula L _R is plotted on the XY coordinate system. The central mountain portion MP is a potential formed by an equation corresponding to the obstacle WO, and the mountain slope portions MK on both sides of the central mountain portion MP on both sides of the valley portion MT are roads. This is a potential formed by a function corresponding to the boundaries ROR and ROL.

  The avoidance path is generated so as to be as much as possible along a region where the value of the risk potential field corresponding to the valley portion MT shown in FIG. 8 is low.

Request item 3 is an item introduced to request efficient avoidance by performing avoidance operation with as small a steering angle as possible. For this evaluation formula L _P , for example, a function of the following formula is used.

以上、三つの評価式に適当な重みづけをして足し合わせた関数を、評価式Ｌを用いる。すなわち、ｗ_R、ｗ_P、ｗ_rをそれぞれ要項項目１、２、３に対する重みづけとすると、評価式Ｌは、

As described above, the evaluation formula L is used as a function obtained by adding appropriate weights to the three evaluation formulas. That is, if w _R , w _P , and w _r are weights for the essential items 1, 2, and 3, respectively, the evaluation formula L is

という式によって表される。

It is expressed by the formula.

Based on the vehicle motion model expressed in this way and the state evaluation function J, the support control amount calculation means 6C calculates the emergency support control amount that optimizes the evaluation function value, in this case, the rear wheel steering angle δ _r . Perform the calculation.

  The problem of obtaining the manipulated variable that optimizes the value of the state evaluation function J in the form as shown in the equation (24) for the control object according to the equation (22) is a problem that is widely known as an optimal control problem. An algorithm for calculating the numerical solution is disclosed as a known technique. One such known document is, for example, “T. Ohtsuka,“ A continuation / GMRES method for fast computation of nonlinear receding horizon control ”, Automatica, vol. 40, 563/574, 2004.”.

Therefore, using such a numerical calculation technique, a time series from the time t to the time t + T of the rear wheel steering angle δ _r that is the support control amount is calculated. In calculating the actual operation amount, the evaluation interval is divided by an appropriate number of steps N, and the value of the operation amount at each discretization step is calculated. That is,

というN成分からなる後輪舵角δ_r ^*の時系列が得られる。

A time series of the rear wheel steering angle δ _r ^* consisting of the N component is obtained.

In step 6, the calculated δ _r ^* is stored in the buffer memory area inside the microprocessor 6, and the processing of the microprocessor 6 ends. The time series of the rear wheel steering angle δ _r ^* as the operation amount stored in the buffer memory area is appropriately read by the rear wheel steering controller 7 as necessary.

  In the case of the first embodiment, when the emergency support control amount is set in the buffer memory area, the rear wheel steering controller 7 is activated, and the steering command value (rear wheel steering angle command value) in the buffer memory area is set to T / N. Are sequentially read, and the rear wheel steering angle servo control is executed with the read rear wheel steering angle command value as the target steering angle.

  When all the operation amounts set in the buffer memory area are read, the servo control is finished and the normal driving state in which the driver operates is restored.

  FIG. 9 shows an example of a correspondence relationship between an example of the front wheel steering angle time series calculated based on the prediction by the driver steering prediction means 6B and the time series of the rear wheel steering angle calculated by the support control amount calculation means 6C. Yes.

  FIG. 10 shows a vehicle locus when only the front wheel 5D is steered, and FIG. 11 shows a vehicle locus when the front wheel 5D and the rear wheel 9D are steered. As shown in FIG. 10, in the case of steering only the front wheels 5D by the driver's operation, the steering angle is large, so that the obstacle WO can be avoided successfully, but the return behavior after avoidance is not in time, and the road boundary ROR This is a vehicle behavior that cannot avoid the partition wall WA.

  On the other hand, when rear wheel steering is applied, the vehicle posture is maintained by first steering in the same direction as the front wheel 5D, and the steering direction of the rear wheel 9D is reversed slightly later than the steering direction of the front wheel 5D changes. As a result, a vehicle behavior is obtained in which a steering state in the reverse phase is formed at the timing of passing right next to the obstacle WO, the vehicle posture is greatly changed, and the deviation from the road is prevented.

  FIG. 12 is a layout diagram of components necessary for the vehicle support control apparatus according to the second embodiment.

  In the second embodiment, the rear wheel 9D is provided with a drive motor 9G and a brake actuator 9H capable of automatic control, and the braking force and driving force of the left and right rear wheels 9D can be adjusted.

  By controlling the drive motor 9G and the brake actuator 9H by the braking force difference controller 7 ', a difference in driving force or braking force generated on the rear wheel 9D between the left and right rear wheels 9D is generated. The configuration is such that the yaw moment is generated in the vehicle body by the driving force difference (braking force difference) of the rear wheel 9D and emergency avoidance support control is performed. Other configurations are the same as those of the first embodiment.

  The second embodiment is almost the same as the first embodiment except that the emergency avoidance support control is executed by the left / right braking / driving force difference in place of the rear wheel steering, and the processing by the microprocessor 6 is also shown in FIGS. This is done according to the flowchart. However, among the equations (12) to (19) representing the vehicle motion model of the vehicle motion prediction means 6E, the equations (17) and (19) are replaced with the following equations (30) and (31). .

また、これに伴って、（２４）式の状態評価関数Ｊを生成する（２８）式で記述されていた評価式Ｌも、後輪舵角δ_rを評価する評価項ｗ_r・Ｌ_rに代わって、後輪左右制駆動力差を評価する評価項ｗ_u・Ｌ_uが加わることになる。すなわち、評価式Ｌは次式のようになる。

Accordingly, the evaluation expression L described in the expression (28) for generating the state evaluation function J of the expression (24) is also changed to the evaluation term w _r · L _r for evaluating the rear wheel steering angle δ _r. Instead, an evaluation term w _u · L _u for evaluating the difference in the left / right braking / driving force of the rear wheels is added. That is, the evaluation formula L is as follows.

ここで、ｗ_uは左右制駆動力差に対する評価重みを表すパラメータである。

Here, w _u is a parameter representing the evaluation weight for the left / right braking / driving force difference.

  Since the left / right braking / driving force difference has an action of controlling the attitude of the vehicle in the same manner as the rear wheel steering, the same effect as that of the first embodiment can be obtained when applied to the scene of FIG.

  FIGS. 13 to 15 are diagrams for explaining the vehicle support control apparatus according to the third embodiment.

  In FIG. 13, 5G is an electromagnetic clutch, and 5H is a front wheel steering motor. The steering wheel 5B and the front wheel steering mechanism 5C are connected by an electromagnetic clutch 5G, and when the electromagnetic clutch 5G is connected, the front wheel steering angle is steered according to the rotation angle of the steering wheel 5B as in the first embodiment. However, when the electromagnetic clutch 5G is disengaged, the front wheel steering angle can be controlled independently of the driver's steering operation by driving the front wheel steering motor 5H.

  Correspondingly, the vehicle 10 is provided with a front wheel steering angle controller 5J and a front wheel steering angle sensor 5M for automatically controlling the front wheels 5D.

  The processing of the microprocessor 6 according to the third embodiment will be described with reference to the flowchart shown in FIG.

  The microprocessor 6 reads and processes a signal from the angle sensor (S.1 '). This step S.I. The process 1 'is the same as the process in the first embodiment.

  Next, the microprocessor 6 determines the necessity of support control (S.2 '). This step S.I. The processing of 2 is the same as that of the first embodiment. For example, when both the expressions (2) and (3) are established, it is determined that the assistance control is necessary. Otherwise, the assistance control is unnecessary. Is determined.

  When the microprocessor 6 determines that the support control is necessary, the microprocessor 6 turns on the support control execution flag for recording the execution state of the support control, and then performs step S.E. 3 'to step S.1. Processes up to 8 'are sequentially executed. Of these processes, step S.E. 3 'and step S.3. The process 4 'is the same process as in the first embodiment.

  Step S. In the process 5 ′, the assistance control amount is basically calculated based on a calculation method similar to the calculation method of the first embodiment. In this embodiment, the assistance control is executed so as to correct the front wheel steering by the driver. Therefore, the vehicle motion prediction means 6E and the state evaluation function J are set according to such a configuration. Specifically, among the equations (12) to (19) representing the vehicle motion model used in the first embodiment, the equation (18) is the following equation (34), and the equation (19) is the equation (31). Is replaced by

ただし、δ_f ^pは運転者操舵予測手段６Ｂによって算出されたステアリング角度に基づいて（２３）式によって算出される前輪操舵角の予測値、δ_f ^uは緊急支援制御による前輪舵角の補正量を表す。

However, δ _f ^p is a predicted value of the front wheel steering angle calculated by the equation (23) based on the steering angle calculated by the driver steering prediction means 6B, and δ _f ^u is a correction amount of the front wheel steering angle by the emergency support control. Represents.

Accordingly, the front wheel rudder angle correction amount is also evaluated in place of the evaluation term for evaluating the rear wheel rudder angle with respect to the evaluation formula L of formula (28) for generating the state evaluation function J of formula (24). An evaluation term will be added.
That is, the evaluation formula L is as follows.

ここで、ｗ_fは前輪舵角補正量に対する評価重み付けを意味するパラメータである。

Here, w _f is a parameter that means evaluation weighting for the front wheel steering angle correction amount.

With these settings, the time series δ _f ^{u * of} the front wheel steering angle correction amount corresponding to the expression (29) of the first embodiment is obtained by using the algorithm for optimization calculation. Therefore, by adding the time series δ _f ^p calculated by the driver steering prediction means 6B, the time series of the front wheel steering angle is obtained from the following equation.

マイクロプロセッサ６は、以前にバッファメモリに記録された制御量の有無に関係なく、バッファメモリの内容をクリアしたうえで、ステップＳ．５’において算出された前輪舵角補正量の時系列（３７）式をバッファメモリに記録する（Ｓ．６’）。

The microprocessor 6 clears the contents of the buffer memory regardless of the presence or absence of the control amount previously recorded in the buffer memory. The time series expression (37) of the front wheel steering angle correction amount calculated in 5 ′ is recorded in the buffer memory (S.6 ′).

  Then, the microprocessor 6 outputs the front wheel steering angle command value recorded at the head of the buffer memory to the front wheel steering angle controller 5J, and the front wheel steering angle controller 5J receives the command value and performs control to realize the command value. Execute.

  Next, the microprocessor 6 deletes the head command value in the buffer memory from the buffer memory and shifts the second and subsequent command values in the head direction. As a result, the command value recorded at the second position becomes the head command value. A command value “0” is recorded at the end of the buffer memory.

  If the microprocessor 2 determines that the emergency support control is not necessary, the microprocessor 2 performs step S.1. In 9 ', it is determined from the value of the assistance control execution flag whether or not emergency assistance control is currently being executed.

  When the microprocessor 2 determines that the support control is not being executed, the microprocessor 2 performs step S.1. In 12 ', the process is ended while the support control execution flag is OFF. If it is determined that the assist control is being executed, step S. 10 '.

  The microprocessor 2 performs step S.1. At 10 ', the contents of the buffer memory are checked to determine whether or not the buffer memory is empty, that is, whether or not all command values in the buffer memory are "0". When the value is “0”, it is determined that the necessary support control has been completed, and step S. Then, the process proceeds to 12 'and the support control execution flag is turned OFF to end the process.

  When a command value other than “0” remains as a command value in the buffer memory, the microprocessor 2 holds the contents of the buffer memory in order to continue control (S.11 ′). The process proceeds to 7 'and the process of sequentially executing the remaining command values is continued.

  FIG. 14 shows an example of the front wheel steering angle when the third embodiment is applied to the scene shown in FIG. 3, and FIG. 15 shows the vehicle motion trajectory when the front wheel steering angle shown in FIG. 13 is corrected. .

  In FIG. 14, the broken line is the steering angle when following the driver's steering, and the solid line is the steering angle when correcting the driver's steering by executing emergency support control.

  In FIG. 14, the steering angle of the emergency support control is smaller than the steering angle of the driver, and the front wheel steering angle is corrected in a direction that suppresses excessive steering by the driver. As a result, when correction is not performed, a result that leads to an out-of-road departure is expected as shown in FIG. 11, whereas in the case of emergency support control execution, as shown in FIG. It is an avoidance route that does not lead to off-road departure.

  In the third embodiment, since the time series of the command value is updated every control cycle as described above, the time series of the command value is updated every control cycle as described above. Even when the driver's steering prediction or the obstacle movement prediction deviates from the initial prediction, an appropriate command value can be calculated based on the latest prediction.

  FIGS. 16 to 19 are diagrams for explaining the vehicle support control apparatus according to the fourth embodiment.

  As the hardware configuration of the vehicle support control apparatus according to the fourth embodiment, the configuration of the deployment structure shown in FIG.

  FIG. 16 is a block diagram of a control system according to the fourth embodiment. In the fourth embodiment, the detection output of the steering angle sensor 5 is input to the microprocessor 6 and the rear wheel steering controller 7. The driver steering prediction means 6B is expanded to include a vehicle motion prediction means 6E 'and a driver steering evaluation function generation means 6F'.

  FIG. 17 is a block diagram showing the signal system of the control system.

  In the first embodiment, the front wheels 5D are steered by the driver's steering operation, and the rear wheels 9D are steered based on the steering command value calculated by the assist control amount calculation means 6C. 4, not only the front wheels 5D but also the rear wheels 9D are steered in accordance with the driver's steering operation even in a normal driving state that does not require emergency avoidance assistance.

  When providing assistance for emergency avoidance, the rear wheel 9D is steered by superimposing the command value calculated by the assist control amount calculation means 6C on the steering command value during normal driving. That is, in the fourth embodiment, compared with the first embodiment, the rear wheel steering control is executed not only during emergency support but also during normal travel.

  Various methods are known as rear wheel steering control laws that are linked to the steering operation of the driver, and appropriate control techniques from among such known technologies are used as the control laws during normal driving in this embodiment. You can choose.

  For example, “Ito, Fujishiro, Kawamata, Kanai, Ochi:“ New Control Method for Four-wheel Steering Vehicle ”, Transactions of the Society of Instrument and Control Engineers, Vol.23, No.8, pp.828 -834 (1987) ".

  Including these known techniques, the control law for rear wheel steering is configured to take the steering angle as input, feed back the yaw rate and vehicle speed signal, and output the rear wheel steering angle. ,

という式で表される。ここで、ｘ_cは後輪操舵制御則の状態量、ｇ、ｈは制御則を表す関数である。

It is expressed by the formula. Here, _xc is a state quantity of the rear wheel steering control law, and g and h are functions representing the control law.

  In the fourth embodiment, during normal avoidance traveling, the rear wheel 9D is steered based on the control law of the equations (38) and (39), and it is determined that emergency support control is necessary (38) The control amount for correcting the control law of the equation (39) is calculated by the support control amount calculation means 6C, and the following equation is calculated:

を最終的な後輪操舵角として実現するという制御を実施する。

Is implemented as the final rear wheel steering angle.

  The processing itself of the microprocessor 6 for calculating the support control amount is almost the same as that of the embodiment, and the processing is performed according to the flowcharts of FIGS. However, the vehicle motion model of the vehicle motion prediction means 6E is changed to the following equation model obtained by combining the equations (22), (23), (38), (39), and (40).

ただし、

However,

である。

It is.

  θs is a time series of the driver steering pattern calculated by the driver steering prediction means 6B.

The evaluation section (27) for evaluating the rear wheel steering angle Accompanying this is replaced with the following evaluation formula for evaluating the correction amount [delta] _r ^u.

また、この実施例４では、図２１に示すステップＳ．４の運転者操舵パターンの予測を、支援制御量算出手段６Ｃと同様の最適化演算に基づいて算出する。すなわち、θ_sを以下の最適化問題を解くことによって得る。

In the fourth embodiment, step S. shown in FIG. 4 of the driver steering pattern is calculated based on the same optimization calculation as the assist control amount calculation means 6C. That is, θ _s is obtained by solving the following optimization problem.

ただし、ｗ_p’、Ｗ_R’は、 それぞれ（２５）、（２６）式の評価項に対する評価重み付けを表すパラメータである。また、ｗθは下記に示す評価項に対する評価重み付けである。

However, w _p ′ and W _R ′ are parameters representing the evaluation weights for the evaluation terms of the expressions (25) and (26), respectively. Further, wθ is an evaluation weight for the evaluation term shown below.

FIG. 18 shows an example of steering obtained by applying the rear wheel steering control law and the driver steering prediction introduced as described above to the scene of FIG. In FIG. 18, the normal rear wheel steering control law is set to improve the turning performance of the vehicle, and the result is that the rear wheel 9D is turned in the opposite phase to the front wheel 5D and the initial turning speed is increased. It has been. As in Example 1, in the pattern the driver front wheel steering angle by the steering until θs reaches the [delta] _f, expected to be traveling locus as equally to road departure that shown in FIG. 10 Is done.

  On the other hand, FIG. 19 shows an example of the result of calculating the emergency support control amount and correcting the rear wheel steering angle. As shown in FIG. 11, the rear wheel 9D steered in the opposite phase direction to the front wheel 5D according to the normal control law is immediately corrected in the same phase direction as the front wheel 5D, thereby stabilizing the vehicle posture. An operation amount that achieves both avoidance of the object WO and prevention of deviation from the road is obtained.

  In the fourth embodiment, the method of using the rear wheel steering in addition to the driver's steering is shown in the normal avoidance traveling, the emergency support, and the left and right driving force (braking force) of the rear wheel 9D in addition to the driver's steering. ) Depending on the difference, a method of generating a yaw moment in the vehicle body may be used.

  In the first to fourth embodiments described above, emergency support is started when all of the formulas (2) to (4) are established, but the host vehicle NS is changed according to the driver steering prediction time series. When driving, if the distance between the vehicle NS and the obstacle WO (or road boundary ROR, ROL) is smaller than a predetermined distance, the emergency support control may be started.

It is explanatory drawing which shows the deployment state of the emergency assistance control apparatus concerning Example 1 of this invention. It is a block diagram for demonstrating the function of the emergency assistance control apparatus shown in FIG. It is a figure which shows an example of the application scene of the emergency assistance control apparatus shown in FIG. It is explanatory drawing which shows the state which set the coordinate system for the definition of the own vehicle state quantity to the application scene shown in FIG. It is explanatory drawing which shows the steering pattern used as the original form of the driver | operator steering prediction of Example 1. FIG. It is explanatory drawing which shows the steering prediction time series of the prediction result of the driver | operator steering prediction of Example 1. FIG. It is explanatory drawing which shows an example of the functional shape of the tire lateral force of a vehicle motion model. It is explanatory drawing which shows an example of the shape of the state evaluation function produced | generated from the obstruction shown in FIG. 3, and a road boundary. FIG. 3 is a diagram showing an example of a front wheel steering time series calculated based on a driver steering prediction means shown in FIG. 2 and a rear wheel steering time series calculated by an optimum support control amount calculating means. It is a figure which shows an example of the vehicle movement locus | trajectory at the time of performing only the front-wheel steering of Example 1. FIG. It is a figure which shows an example of the vehicle movement locus | trajectory at the time of performing rear-wheel steering in addition to the front-wheel steering of Example 1. FIG. It is explanatory drawing which shows the deployment state of the emergency assistance control apparatus concerning Example 2 of this invention. It is explanatory drawing which shows the deployment state of the emergency assistance control apparatus concerning Example 3 of this invention. FIG. 10 is an explanatory diagram illustrating a front wheel steering angle time series when a front wheel steering time series calculated based on a driver steering prediction unit according to a third embodiment and a correction amount calculated by a support control amount calculation unit are added. It is a figure which shows an example of the vehicle movement locus | trajectory at the time of correct | amending the front-wheel steering of Example 3. FIG. It is a block diagram for demonstrating the function of the emergency assistance control apparatus of Example 4 of this invention. FIG. 10 is a block diagram of a signal system of a control system according to a fourth embodiment. FIG. 14 is a diagram illustrating a time series of front wheel steering angles calculated by a driver steering prediction unit according to a fourth embodiment and a time series of rear wheel steering angles when an estimated steering pattern is executed. FIG. 10 is a diagram showing a rear wheel steering angle time series when a correction amount calculated by the assist control amount calculating means is added to the rear wheel steering angle of the fourth embodiment. It is a process flowchart of the microprocessor of Example 1 of this invention. Step S. of FIG. 3 is a flowchart showing a detailed procedure of processing 1. It is a process flowchart by the microprocessor of Example 3 of this invention.

Explanation of symbols

6 ... Microprocessor (Emergency obstacle avoidance means)
10D: Vehicle steering means during normal operation

Claims (10)

A front condition detecting means for detecting a road condition in front of the own vehicle including an obstacle located in front of the own vehicle and a road boundary in front of the own vehicle; a driving condition detecting means for detecting the driving condition of the own vehicle; and driving Steering amount detection means for detecting the steering amount of the driver, normal time vehicle steering means for driving the steering system of the vehicle according to the steering amount of the driver, and avoidance control by the normal time vehicle steering means of the driver Comprises emergency obstacle avoiding means for issuing an instruction to avoid the obstacle when it is determined that the obstacle cannot be avoided.
The emergency obstacle avoidance means is based on the normal vehicle steering means based on the position of the obstacle detected by the forward situation detection means and the running state of the host vehicle detected by the own vehicle running state detection means. The emergency support necessity determination means for determining whether or not the obstacle can be avoided by avoidance control, and a predetermined time from the current time when it is determined that emergency support is required based on the emergency support necessity determination means A driver steering prediction means for calculating a time series of steering expected to be executed by the driver by an elapsed time after the elapse of time, and the emergency support necessity determination means when the emergency support is determined to be necessary Assistance control amount calculation means for calculating an emergency assistance control amount for avoiding obstacles, and wheels in an emergency based on the emergency assistance control amount obtained by the assistance control amount calculation means And a Kyuji wheel control means,
The assist control amount calculation means includes vehicle motion prediction means for predicting vehicle motion at the time of emergency support based on a time series of steering by the driver steering prediction means, and from the current time to an elapsed time after elapse of a predetermined time. A state evaluation function generating means for generating a state evaluation function for evaluating an obstacle avoidance risk state provided from a relationship between the prediction result of the vehicle motion between the vehicle and the obstacle, and the normal vehicle steering means. Calculation means for calculating the emergency assistance control amount based on the state evaluation function so that the avoidance risk state of the vehicle travel locus determined by working is appropriate ,
The driver steering prediction means has a plurality of predetermined steering patterns, and steers from the plurality of steering patterns based on the steering amount at the current time and the steering speed of the driver at the current time. A vehicle assistance control device that generates a driver steering prediction time series by selecting a pattern . A front condition detecting means for detecting a road condition in front of the own vehicle including an obstacle located in front of the own vehicle and a road boundary in front of the own vehicle; a driving condition detecting means for detecting the driving condition of the own vehicle; and driving Steering amount detection means for detecting the steering amount of the driver, normal time vehicle steering means for driving the steering system of the vehicle according to the steering amount of the driver, and avoidance control by the normal time vehicle steering means of the driver Comprises emergency obstacle avoiding means for issuing an instruction to avoid the obstacle when it is determined that the obstacle cannot be avoided.
The emergency obstacle avoidance means is based on the normal vehicle steering means based on the position of the obstacle detected by the forward situation detection means and the running state of the host vehicle detected by the own vehicle running state detection means. The emergency support necessity determination means for determining whether or not the obstacle can be avoided by avoidance control, and a predetermined time from the current time when it is determined that emergency support is required based on the emergency support necessity determination means A driver steering prediction means for calculating a time series of steering expected to be executed by the driver by an elapsed time after the elapse of time, and the emergency support necessity determination means when the emergency support is determined to be necessary Assistance control amount calculation means for calculating an emergency assistance control amount for avoiding obstacles, and wheels in an emergency based on the emergency assistance control amount obtained by the assistance control amount calculation means And a Kyuji wheel control means,
The assist control amount calculation means includes vehicle motion prediction means for predicting vehicle motion at the time of emergency support based on a time series of steering by the driver steering prediction means, and from the current time to an elapsed time after elapse of a predetermined time. A state evaluation function generating means for generating a state evaluation function for evaluating an obstacle avoidance risk state provided from a relationship between the prediction result of the vehicle motion between the vehicle and the obstacle, and the normal vehicle steering means. Calculation means for calculating the emergency assistance control amount based on the state evaluation function so that the avoidance risk state of the vehicle travel locus determined by working is appropriate,
The driver steering prediction means includes state evaluation function generation means for generating a state evaluation function for evaluating a state of vehicle motion generated as a result of steering applied between the current time and after a predetermined time has elapsed. A vehicle support control device characterized by the above. The emergency obstacle avoidance means includes obstacle movement trajectory prediction means for predicting a movement trajectory of the obstacle, the state evaluation function includes the movement trajectory of the obstacle, and the emergency support control amount is the obstacle The vehicle support control apparatus according to claim 1 , wherein the vehicle support control apparatus is determined in consideration of an object movement trajectory. The normal vehicle steering means is configured to steer front wheels in proportion to the steering amount of the driver, and the emergency wheel control means is configured to steer left and right rear wheels. The vehicle support control device according to claim 1 . The normal vehicle steering means is configured to steer front wheels in proportion to the steering amount of the driver, and the emergency wheel control means controls the rear wheels based on the difference in braking force between the left and right rear wheels. The vehicle support control device according to claim 1 , wherein the vehicle support control device is a structure to support the vehicle. The normal vehicle steering means is configured to steer front wheels in proportion to the steering amount of the driver, and the emergency wheel control means is corrected to a steering angle corresponding to the steering amount of the normal vehicle steering means. The vehicle support control device according to claim 1 , wherein the vehicle support control device has a structure to which a vehicle is added. The normal vehicle steering means is configured to steer the front wheels in proportion to the steering amount of the driver and to generate a difference between the steering amount of the rear wheels or the braking force of the rear wheels, and the emergency wheel control means 3. The vehicle support control device according to claim 1 , wherein the vehicle is a structure for steering the left and right rear wheels or a structure for controlling the rear wheels based on a difference in braking force between the left and right rear wheels. . The emergency support necessity determination means includes a relative position between the host vehicle and an obstacle existing ahead of the host vehicle, a relative speed of the obstacle with respect to the host vehicle, a steering amount of the driver, and a steering speed of the driver. The vehicle support control device according to claim 1 or 2 , wherein emergency support is started when and satisfy a predetermined condition. The emergency support necessity determining means, when driving the vehicle according to the driver steering prediction time series, the distance between the vehicle and the obstacle is less than a predetermined value or the distance between the vehicle and the road boundary is less than a predetermined value In this case, emergency support is started, and the vehicle support control device according to claim 1 or 2 . After emergency assistance initiated a predetermined time repeatedly calculating the assist control amount for each interval, as a target value of the assist control amount that is updated by updating the assist control amount, according to claim 1 or claim, characterized in that an emergency assistance Item 3. The vehicle support control device according to Item 2 .

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