JP2014101100A - Driving support system of vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To apply an assistive force to a driver's steering wheel manipulation for drivers who are different from one another in a driving expertise or driving tendency may feel awkward.SOLUTION: A driving support system of a vehicle includes a camera 11 that detects a lane in front of an own vehicle 1, a camera ECU 12 that discriminates a travel state of the own vehicle 1 in the lane, an electric power steering 13 that applies an assistive force to a steering unit of the own vehicle 1, and an LKA ECU 16 that determines the direction and magnitude of the assistive force according to the travel state of the own vehicle 1 so that the own vehicle 1 can travel in the lane. The LKA ECU 16 identifies a forward watching distance of a driver, and augments the assistive force more greatly as the forward watching distance is shorter.

Description

  The present invention relates to a vehicle driving support device that supports a driver's driving of a vehicle, and more particularly, to a lane keeping support device that prevents a vehicle from deviating from a lane by mistake.

  Conventionally, among various vehicle driving support devices, in order to prevent the vehicle from accidentally deviating from the lane, in other words, to assist the driver in operating the steering wheel so that the vehicle travels in the lane. As a lane maintenance assist (LKA: Lane Keep Assist) device to be given, technologies described in Patent Literature 1 and Patent Literature 2, for example, are known.

  Patent Document 1 describes a technology for assisting a driving operation in accordance with a desired degree of driving in the center of a driver's lane.

  In Patent Document 2, the driver feels uncomfortable by driving an electric motor for turning the traveling direction of the vehicle with a time delay comparable to the time lag until the driver actually starts the steering operation. Techniques for reducing are described.

JP 2000-215395 A (paragraph 0043) JP 2009-161100 A (paragraphs 0072 to 0073)

  By the way, the driver has different driving skill and driving tendency. For example, there are a driver who tries to reach the center of the lane early and a driver who tries to reach the center slowly when changing lanes. If this is not taken into consideration in the LKA device, an assist force that does not conform to the driver's will will be applied, giving the driver a sense of incongruity.

  SUMMARY OF THE INVENTION An object of the present invention is to provide a vehicle driving support device that applies assist force to a driver's steering operation so as not to give a sense of incongruity to drivers having different driving skills and driving tendencies.

  In order to solve the above-described problems, the present invention provides a detection unit that detects a lane ahead of the host vehicle, a determination unit that determines a traveling state of the host vehicle in the lane detected by the detection unit, and a host vehicle. An assisting means for applying an assisting force to the steering device, and a direction of the assisting force so that the host vehicle travels in the lane detected by the detecting unit according to the traveling state of the host vehicle determined by the determining unit. And a driving support device for a vehicle having a control means for determining a size, wherein a determination means for determining a driver's forward gaze distance is provided, and the control means is a forward gaze distance determined by the determination means The driving assistance device for a vehicle is characterized in that the magnitude of the auxiliary force increases as the length of the vehicle decreases.

  According to the present invention, the control (LKA control) for determining the direction and magnitude of the assisting force (assist force) applied to the steering device so that the host vehicle travels in the lane according to the traveling state of the host vehicle is executed. In a possible vehicle driving support device, the smaller the driver's forward gaze distance, the greater the magnitude of the assisting force applied to the steering device. A driver with a short forward gaze distance is a driver who tries to reach the target course early, so for such a driver, the magnitude of the assisting force applied to the steering device is increased, Auxiliary power in line with the driver's will is provided. Conversely, a driver with a long forward gaze distance is a driver who tries to reach the target course slowly, so that the magnitude of the assisting force applied to the steering device is reduced for such a driver. As a result, an assisting force according to the intention of the driver is also given. Therefore, in any case, it is suppressed that the driver feels uncomfortable.

  In the present invention, it is preferable that switching means for switching between operation and non-operation of the control means is provided, and the determination means determines a forward gaze distance when the control means is inactive by the switching means ( Claim 2).

  According to this configuration, in other words, when the control means is inactive, that is, in a state where the assisting force is not applied to the steering device so that the host vehicle travels in the lane according to the traveling state of the host vehicle. For example, since the driver's forward gaze distance is determined without the LKA control intervening, the driver's original forward gaze distance is correctly determined.

  In the present invention, it is preferable that the determination unit includes a timing of turning back in the steering direction performed by the driver while the host vehicle is traveling toward a predetermined target course in the lane detected by the detection unit. Compared with the timing of turning back in the steering direction performed by the control means when the control means is operating, when the former is early, the driver's front gaze distance is more than the most recently determined front gaze distance If the latter is early, it is determined that the driver's forward gaze distance is shorter than the most recently determined forward gaze distance.

  According to this configuration, an example of the determination operation performed by the determination unit is embodied. According to this, the timing of turning back in the steering direction actually performed by the driver is compared with the timing of turning back in the steering direction that would have been performed by the control means if the control means executed LKA control. . When the turning direction of the steering direction that the driver actually performs is earlier than the turning direction of the steering direction that the control means would have performed, the forward gaze distance of the driver is It is determined that the gaze distance is longer than the gaze distance (the front gaze distance used by the control unit to execute the temporary LKA control). For example, the situation is as follows.For example, the driver tries to reach the target course slowly, and before the host vehicle reaches the target course, the steering direction is changed from a left turn to a right turn or from a right turn to a left turn. This can happen when switching back. Therefore, in this case, it is reasonable to determine that the driver's forward gaze distance is long. On the contrary, when the turning direction of the steering direction that the control means would have performed is earlier than the timing of the turning direction of the steering direction actually performed by the driver, the driver's forward gaze distance is determined to be the latest. It is determined that the distance is shorter than the front gaze distance (the front gaze distance used by the control unit to execute the temporary LKA control). The situation as described above is, for example, that the driver tries to reach the target course early, and after the host vehicle reaches the target course, the steering direction is delayed from the left turn to the right turn or from the right turn to the left turn. This can happen when switching back. Therefore, in this case, it is reasonable to determine that the driver's forward gaze distance is short.

  In the present invention, preferably, recording means for updating and recording the forward gaze distance determined by the determination means is provided, and the control means uses the front gaze distance recorded in the recording means. ).

  According to this configuration, the direction and magnitude of the assisting force applied to the steering device is determined using the last gaze distance determined last (closest) by the judging means, so that the latest front gaze distance is always considered. As a result, LKA control is executed.

  ADVANTAGE OF THE INVENTION According to this invention, assist power can be provided to a driver | operator's handle | steering-wheel operation so that it may not give discomfort to each driver from whom driving skill and driving tendency differ.

1 is a schematic configuration diagram of a driving support apparatus for a vehicle according to an embodiment of the present invention. It is a functional block diagram of the driving support device. It is explanatory drawing of the driver model used for the fundamental operation | movement of the said driving assistance apparatus. It is explanatory drawing of the relationship between a front gaze distance and a steering direction. It is explanatory drawing of the determination process of a front gaze distance. It is explanatory drawing of the relationship between a vehicle speed and a front gaze distance. It is a flowchart of the determination operation | movement of the front gaze distance which the said driving assistance device performs. 4 is a flowchart of a driving support operation performed by the driving support device.

(1) Configuration of Hardware FIG. 1 is a schematic configuration diagram of a driving support device for a vehicle 1 according to the present embodiment. More specifically, the driving support device for the vehicle 1 according to the present embodiment prevents the vehicle 1 from accidentally deviating from the lane, in other words, the vehicle 1 travels in the lane. Is a lane keeping assist device (LKA device) that applies assist force to the driver's steering wheel operation so that the vehicle travels in the center of the lane as much as possible.

  The vehicle 1 includes a steering wheel 2 in a driver seat. When the driver steers the steering wheel 2 to the right or left, the steering shaft 3 rotates to the right or left, and the vehicle 1 turns to the right or left. The steering wheel 2 and the steering shaft 3 constitute a steering device for the vehicle 1.

  The vehicle 1 includes a camera 11 (corresponding to the detection means of the present invention) at the front end of the vehicle body. The camera 11 is an optical camera such as a CMOS (Complementary Metal Oxide Semiconductor) camera. The camera 11 images an environment (a road, a lane, etc.) ahead of the host vehicle 1.

  An image signal is transmitted from the camera 11 to a camera ECU (Electronic Control Unit) 12 (corresponding to the determination means of the present invention). The camera ECU 12 is an image processing ECU such as a DSP (Digital Signal Processor). An image signal from the camera 11 is image-processed by the camera ECU 12, and the lateral position of the host vehicle 1 in the lane, the attitude angle (orientation) of the host vehicle 1 in the lane, the curvature of the lane, the clothoid parameter of the lane, etc. Information is generated. The generated information is transmitted from the camera ECU 12 to the LKA (Lane Keep Assist) ECU 16 (corresponding to the control means, determination means, and recording means of the present invention) via, for example, CAN (Controller Area Network) communication. The lateral position and the posture angle of the host vehicle 1 in the lane constitute the traveling state of the host vehicle 1.

  The vehicle 1 includes an electric power steering (EPS) 13 (corresponding to auxiliary means of the present invention) that applies assist force to the steering device. The EPS 13 includes an electric motor 14 that rotates the steering shaft 3 via a gear, and an EPS ECU 15. A drive current is applied to the electric motor 14 from the EPSECU 15, and a rotation angle signal of the motor shaft is transmitted from the electric motor 14 to the EPSECU 15. The illustrated example is a column assist type, but may be a rack assist type.

  The EPS ECU 15 determines, as a basic operation, the direction and magnitude of the assist force that the EPS 13 applies to the steering device to reduce the driver's steering force. Specifically, the EPS ECU 15 sets the direction of the assist force as the direction in which the steering shaft 3 or the steering wheel 2 rotates to the left if the steering direction of the driver is turning left, and if the steering direction of the driver is turning right. The direction of the assist force is the direction in which the steering shaft 3 or the steering wheel 2 rotates to the right. The EPS ECU 15 increases the assist force as the driver's steering amount (steering angle) increases, and decreases the driver's steering amount as the driver's steering amount decreases. In addition to such an operation, the EPS ECU 15 also adjusts the assist force in consideration of the steering angular velocity and the like, and performs assist in accordance with the driver's feeling.

  The vehicle 1 includes a torque sensor 21 and a steering angle sensor 22 in a steering device. The torque sensor 21 detects the torsional displacement of the steering shaft 3, that is, the steering torque. The steering angle sensor 22 detects the rotation angle of the steering shaft 3, that is, the steering angle. A signal related to the steering torque detected by the torque sensor 21 is transmitted to the LKA ECU 16 via the EPS ECU 15. A signal related to the steering angle (including the steering angular velocity) detected by the steering angle sensor 22 is transmitted to the LKA ECU 16 via the handle ECU 17.

  The vehicle 1 includes an inertial sensor 23 that detects the inertial force of the vehicle body. A signal relating to the inertial force detected by the inertial sensor 23 is transmitted to the skid prevention device ECU18. The side slip prevention device ECU 18 processes a signal related to the inertial force from the inertial sensor 23 and generates information such as a yaw rate, a lateral acceleration, and a longitudinal acceleration. The generated information is transmitted from the skid prevention device ECU 18 to the LKA ECU 16.

  The vehicle 1 includes a wheel speed sensor 24 that detects the rotational speed of the wheel 4. A rotation speed detected by the wheel speed sensor 24, that is, a signal related to the vehicle speed is transmitted to the LKA ECU 16.

  The vehicle 1 includes an LKA switch 5 (corresponding to the switching means of the present invention) on the steering wheel 2. The LKA switch 5 is operated by the driver. The LKA switch 5 is an LKA control executed by the LKA ECU 16 (control for determining the direction and magnitude of the assist force applied to the steering device so that the host vehicle 1 travels in the lane according to the travel state of the host vehicle 1). Set ON or OFF. A signal relating to the set ON or OFF is transmitted to the LKA ECU 16. When the ON signal is transmitted to the LKA ECU 16, the LKA ECU 16 is activated, and the LKA control intervenes in the basic operation of the EPS ECU 15 (the assist torque calculated by the assist torque calculator of FIG. 2 described later is transferred from the assist torque calculator to the EPS ECU 15). To be output). When the OFF signal is transmitted to the LKA ECU 16, the LKA ECU 16 is deactivated, and the LKA control does not intervene in the basic operation of the EPS ECU 15 (the assist torque is not output from the assist torque calculator to the EPS ECU 15).

  In this way, the LKA ECU 16 inputs information such as the lateral position of the host vehicle 1 in the lane, the attitude angle of the host vehicle 1 in the lane, the curvature of the lane, and the clothoid parameter of the lane from the camera ECU 12, and from the ECU ECU 15, A signal related to the steering torque is input, a signal related to the steering angle including the steering angular velocity is input from the handle ECU 17, information such as the yaw rate, the lateral acceleration, and the longitudinal acceleration is input from the skid prevention device ECU 18, and the wheel speed sensor 24 is input. Then, a signal relating to the vehicle speed is inputted, and a signal relating to ON or OFF of LKA control is inputted from the LKA switch 5.

  The LKA ECU 16 operates as a basic operation so that the host vehicle 1 travels in the lane detected by the camera 11 in accordance with the traveling state of the host vehicle 1 determined by the camera ECU 12. The direction and the magnitude of the assist force that the EPS 13 applies to the steering device are determined so that 1 runs as far as possible in the center of the lane. Specifically, as will be described in detail later, the LKA ECU 16 sets the target vehicle 1 after τ seconds when the center of the lane is the target course and the driver's forward gaze distance L is “L = vehicle speed V × τ seconds”. Determine the direction and magnitude of the assist force to reach the target position on the course. The LKA ECU 16 outputs a signal relating to the determined direction and magnitude of the assist force to the EPS ECU 15 as a command signal. The EPS ECU 15 applies a drive current to the electric motor 14 in accordance with this command signal as described above.

(2) Configuration of Software FIG. 2 is a functional block diagram of the driving support device with the LKA ECU 16 as the center. The LKA ECU 16 is a microprocessor that includes a CPU, a ROM, a RAM, and the like. As shown in FIG. 2, the LKA ECU 16 includes a target yaw rate calculation unit, an assist torque calculation unit, and a steering torque-assist torque comparison calculation unit.

  The target yaw rate calculation unit includes a lane curvature, a lane clothoid parameter, a lateral position of the host vehicle 1 in the lane, a posture angle of the host vehicle 1 in the lane, a vehicle speed of the host vehicle 1, and a steering torque-assist torque comparison calculation unit. The target yaw rate (target turning radius) is calculated on the basis of the driver's forward gaze distance L provided from.

  The assist torque calculator is configured to assist torque (assist force) based on the target yaw rate provided from the target yaw rate calculator, the lateral position of the host vehicle 1 in the lane, the attitude angle of the host vehicle 1 in the lane, the yaw rate, and the lateral acceleration. ) Is calculated. More specifically, as described above, the direction and magnitude of the assist torque are calculated. The calculated assist torque is provided to EPSECU 15.

  The steering torque-assist torque comparison calculation unit determines the driver's forward gaze distance L based on the assist torque, the steering torque, and the lateral position of the host vehicle 1 in the lane. The determined forward gaze distance L of the driver is provided to the target yaw rate calculation unit as described above. However, the steering torque-assist torque comparison calculation unit determines the driver's forward gaze distance L only when an LKA control OFF signal is provided from the LKA switch 5.

  Here, the target yaw rate calculation unit calculates a larger target yaw rate (small target turning radius) as the driver's forward gaze distance L is shorter. The assist torque calculation unit calculates a larger target steering angle as the target yaw rate is larger, and calculates a larger assist torque as the target steering angle is larger. Conversely, the target yaw rate calculation unit calculates a smaller target yaw rate (larger target turning radius) as the driver's forward gaze distance L is longer. The assist torque calculation unit calculates a smaller target steering angle as the target yaw rate is smaller, and calculates a smaller assist torque as the target steering angle is smaller.

[A] LKA Control Next, referring to FIG. 3, LKA control, that is, the own vehicle 1 travels in the lane according to the traveling state (lateral position and attitude angle in the lane) of the own vehicle 1. The contents of the control for determining the direction and magnitude of the assist torque applied to the steering device will be described.

  FIG. 3 is an explanatory diagram of a driver model used for the basic operation of the driving support apparatus. In general, the driver steers to control the lateral position of the vehicle 1. That is, the driver is steering while looking at the front and predicting the future position of the vehicle 1.

In FIG. 3, L is the driver's forward gaze distance (vehicle speed V × τ seconds). The predicted position y ′ of the vehicle 1 after τ seconds is a predicted value Lθ of a linear future position based on the attitude angle θ of the vehicle 1 with the current position of the camera 11 provided at the front end of the vehicle body as the origin of coordinates, It is obtained by adding the predicted value (L ² / 2R) of the future position based on the arc considering the turning radius R (yaw rate) from the current steering angle (y ′ = Lθ + (L ² / 2R)). If the deviation between the predicted position y ′ and the target position y0 on the target course after τ seconds is ε, the LKA ECU 16 assists the driver's steering so that ε becomes zero. Specifically, the LKA ECU 16 calculates a target yaw rate (target turning radius) so that ε becomes zero, calculates a target steering angle based on the target yaw rate, and assist torque based on the target steering angle. Calculate the direction and magnitude of the assist torque.

[B] Judgment Control for Forward Gaze Distance Next, the details of the control for judging the driver's forward gaze distance will be described with reference to FIGS. 4 and 5.

  FIG. 4 is an explanatory diagram of the relationship between the forward gaze distance and the steering direction. Even if the lateral position and attitude angle of the vehicle 1 with respect to the target course (for example, the center of the lane) are the same, the steering direction turns right or turns left depending on the driver's forward gaze distance (vehicle speed V × τ seconds). . This depends on the driving skill and driving tendency of the driver.

  In the illustrated example, the vehicle 1 on the left side of the target course is traveling toward the target course. A driver with a short forward gazing distance indicated by reference sign (i) tries to reach the target course early, and the steering direction is still turning right. Conversely, a driver with a long forward gazing distance as indicated by reference numeral (iii) tries to reach the target course slowly, so that the steering direction has already been switched to the left turn at the present time. Symbol (ii) is the distance from the vehicle 1 to the intersection of the center line of the vehicle 1 and the target course at the present time. The driver having this distance (ii) as the forward gaze distance switches the steering direction from the right turn to the left turn at the present time. That is, the steering torque (steering force) is zero.

  Therefore, for example, if the LKA ECU 16 has the distance (ii) (for example, 50 m) as the reference forward gaze distance, a driver having a shorter forward gaze distance (i) (for example, 40 m) is slower than the LKA ECU 16. Thus, the steering direction is switched back from the right turn to the left turn (since it is still turning right). Conversely, a driver having a forward gaze distance (iii) (for example, 60 m) longer than the reference forward gaze distance switches the steering direction from the right turn to the left turn at an earlier timing than the LKA ECU 16 (already at this time). Because it turns back to the left).

  Therefore, the timing of turning back in the steering direction performed by the driver is compared with the timing of turning back in the steering direction performed by the LKA ECU 16, and when the driver turns back at an earlier timing than the LKA ECU 16, the driver's forward gaze distance is LKA ECU 16. It can be determined that the distance is longer than the forward gaze distance. Conversely, when the driver turns back at a later timing than LKAECU 16, it can be determined that the driver's front gaze distance is shorter than LKAECU16's front gaze distance.

  When it is determined that the driver's forward gaze distance is longer than the front gaze distance of the LKAECU 16, the front gaze distance of the LKAECU 16 is increased by a slight adjustment distance. When it is determined that the distance is shorter than the forward gaze distance, the forward gaze distance of the LKAECU 16 is shortened by a slight adjustment distance, and in any case, the driver's turn-back timing and the turn-back timing of the LKA ECU 16 are compared again. By repeating this, finally, the forward gaze distance of the LKA ECU 16 at which the driver's switching timing and the switching timing of the LKA ECU 16 coincide is determined. Since the reference forward gaze distance and the adjustment distance in the middle that LKAECU 16 had initially are known, the final gaze distance of LKA ECU 16 that is finally determined can be calculated and determined as the driver's forward gaze distance Can do.

  Therefore, it can be said that the front gaze distance of LKAECU16 here is the front gaze distance determined most recently.

  FIG. 5 is an explanatory diagram of the forward gaze distance determination process. The illustrated example shows a case where the vehicle 1 on the right side of the target course (for example, the center of the lane) sequentially turns left, right, left, and right while traveling toward the target course.

  In the figure, a solid line indicates a change in the direction and magnitude of the steering torque actually performed by the driver during the travel, and a chain line indicates the direction and magnitude of the assist torque calculated by the LKA ECU 16 by the LKA control during the travel. This shows the change in height. Here, the LKAECU 16, more specifically, the target yaw rate calculation unit and the assist torque calculation unit calculate the direction and magnitude of the assist torque by the method described with reference to FIG.

  In the figure, “zero cross” means a timing at which the steering torque of the driver or the assist torque of the LKA ECU 16 becomes zero, that is, a timing at which the steering direction is switched back from a left turn to a right turn or from a right turn to a left turn. Show.

  As described above, the LKA ECU 16, more specifically, the steering torque-assist torque comparison calculation unit, determines the driver's forward gaze distance only when the LKA control OFF signal is input from the LKA switch 5. The reason is that when the OFF signal is input, the LKA ECU 16 is deactivated, and the LKA control does not intervene in the basic operation of the EPS ECU 15, so that it is possible to more accurately determine the forward gaze distance originally possessed by the driver. It is. Specifically, in FIG. 2, the LKA ECU 16 does not output the direction and magnitude of the assist torque calculated by the assist torque calculation unit to the EPS ECU 15 (does not intervene in the basic operation of the EPS ECU 15), and the direction and magnitude of the assist torque. (The direction and the magnitude of the assist torque are provided from the assist torque calculation unit to the steering torque-assist torque comparison calculation unit). That is, the assist torque indicated by the chain line in FIG. 5 is assist torque output from the LKA ECU 16 to the EPS ECU 15 when the LKA ECU 16 is operating.

  In FIG. 5, when the steering torque zero cross is compared with the assist torque zero cross, the assist torque zero cross occurs earlier than the steering torque zero cross. That is, the driver turns the steering direction at a timing later than the LKA ECU 16. This indicates that the driver's front gaze distance is shorter than the front gaze distance of the LKA ECU 16 as described above. In this case, the steering torque-assist torque comparison calculation unit of the LKA ECU 16 shortens the forward gaze distance of the LKA ECU 16 by a slight adjustment distance (for example, 50 m is changed to 48 m). Then, the target yaw rate calculation unit and the assist torque calculation unit of the LKA ECU 16 calculate the direction and the magnitude of the assist torque again by the method described with reference to FIG. 3, and the steering torque-assist torque comparison calculation unit The torque zero cross is compared with the assist torque zero cross. By repeating this, the front gaze distance of the LKA ECU 16 in which the zero cross of the steering torque (driver's turn-back timing) and the zero cross of the assist torque (the turn-back timing of the LKA ECU 16) coincide is calculated, and the LKA ECU 16 It is determined as the driver's forward gaze distance.

  The above is the case where the zero cross of the assist torque occurs earlier than the zero cross of the steering torque. Conversely, when the zero cross of the steering torque occurs earlier than the zero cross of the assist torque, the same operation is performed in accordance with this. A person's forward gaze distance can be determined.

  The LKA ECU 16 performs such determination of the driver's forward gaze distance for each driver and for each vehicle speed. The obtained data (front gaze distance) is stored in a database stored in the memory for each driver and for each vehicle speed. , Record rewritable (updatable).

  For example, the LKA ECU 16 identifies the driver by communicating with a smart card carried by the driver, and if the driver changes, determines the forward gaze distance and updates the database.

  Further, as shown in FIG. 6, since the forward gaze distance changes according to the vehicle speed, the LKA ECU 16 determines the forward gaze distance and updates the database when the vehicle speed changes (for example, every 5 km / h). Do.

  Further, the LKA ECU 16 determines the driver's forward gaze distance when the deviation of the lateral position of the vehicle 1 from the target course is large, that is, the driver moves the vehicle 1 to the target course (center of the lane) from now on. (E.g., when the vehicle 1 is largely deviated laterally from the center of the lane when driving on a curve, or when the vehicle 1 is at the end of the lane when changing lanes). The reason is that when the lateral position deviation of the vehicle 1 from the target course is large, the steering angle (steering amount) of the driver is large, so that the steering direction (right turn or left turn) can be detected stably. This is because the forward gaze distance can be determined more accurately.

  Reference is again made to FIG. As described above, the assist torque shown in FIG. 5 is a provisional assist torque for more accurately determining the driver's forward gaze distance, but a case is considered where this is actually applied to the steering device. That is, a case is considered in which the LKA control is performed while the zero cross of the steering torque (driver's switching timing) and the zero cross of the assist torque (the switching timing of the LKA ECU 16) do not match.

  For example, taking periods a and c as an example, during this period a and c, the driver is still steering the steering wheel 2 to the left, but the assist torque of the LKA control tries to move the steering wheel 2 to the right. To do. Taking periods b and d as an example, during this period b and d, the driver is still steering the steering wheel 2 to the right, but the assist torque of the LKA control seems to move the steering wheel 2 to the left. And Such assist torque in the direction opposite to the steering direction of the driver is assist torque that does not conform to the driver's intention, and gives the driver a sense of incongruity.

  However, in the present embodiment, as described above, the forward gaze distance of the LKA ECU 16 at which the zero cross of the steering torque and the zero cross of the assist torque coincide with each other is finally determined. Therefore, in the LKA control, the direction opposite to the steering direction of the driver Such a problem that the assist torque is applied is avoided.

(3) Control Operation [A] Forward Gaze Distance Determination Operation FIG. 7 is a flowchart of the forward gaze distance determination operation performed by the driving support device, more specifically, the steering torque-assist torque comparison calculation unit of the LKA ECU 16.

  This flowchart is performed for each driver, and starts when the driver operates the LKA switch 5 to OFF.

  In step S1, the LKA ECU 16 determines whether or not the vehicle position condition is met. That is, it is determined whether or not the deviation of the lateral position of the vehicle 1 from the target course is large.

  As a result, if YES, the LKA ECU 16 proceeds to step S12 and determines whether or not the assist torque is zero cross.

  As a result, if YES, the LKA ECU 16 evaluates the steering torque value up to T seconds before the current time in step S13.

  Next, in step S14, the LKA ECU 16 determines whether or not there is a zero cross in the steering torque T seconds before the current time.

  As a result, when YES, the LKA ECU 16 determines in step S15 whether the direction of the zero crossing of the steering torque determined to be step S14 is the same as the direction of the zero crossing of the assist torque determined to be step S12. Determine whether or not. That is, it is determined whether or not both zero crosses coincide with each other in the zero cross from the left turn to the right turn or the zero cross from the right turn to the left turn.

  As a result, when YES, that is, when the driver's turn-back timing is earlier than the turn-back timing of LKAECU 16 (when the driver's front gaze distance is longer than the front gaze distance of LKAECU 16), LKAECU 16 performs step S16. Pick up the forward gaze distance L of the current vehicle speed. That is, the current gaze distance of the current LKAECU 16 at the current vehicle speed (the front gaze distance determined most recently, and the front gaze distance used by the LKAECU 16 to execute temporary LKA control) is read from the database.

  Next, the LKA ECU 16 increases the picked-up forward gaze distance L by ΔL in step S17. That is, the read forward gaze distance of the current LKA ECU 16 is lengthened by a slight adjustment distance. Instead of this, the forward gaze time τ of the current LKA ECU 16 may be increased by Δτ.

  Then, in step S8, the LKAECU 16 records the data obtained in step S17 (the forward gaze distance L of the LKAECU 16 increased by ΔL) in the database for each driver and each vehicle speed. That is, the database is updated. Then, the LKA ECU 16 returns to step S1.

  The LKA ECU 16 executes steps S22 to S27 in parallel with the steps S12 to S17.

  That is, if YES in step S1, the LKA ECU 16 proceeds to step S22 and determines whether or not the steering torque is zero cross.

  As a result, if YES, the LKA ECU 16 evaluates the assist torque value up to T seconds before the current time in step S23.

  Next, in step S24, the LKA ECU 16 determines whether there is a zero cross in the assist torque T seconds before the current time.

  As a result, if YES, the LKA ECU 16 determines in step S25 that the assist torque zero-cross direction determined to be step S24 is the same as the steering torque zero-cross direction determined to be step S22. Determine whether or not. That is, it is determined whether or not both zero crosses coincide with each other in the zero cross from the left turn to the right turn or the zero cross from the right turn to the left turn.

  As a result, when the answer is YES, that is, when the turning timing of the LKA ECU 16 is earlier than the turning timing of the driver (when the driver's front gaze distance is shorter than the front gaze distance of the LKA ECU 16), the LKA ECU 16 performs step S26. Pick up the forward gaze distance L of the current vehicle speed. That is, the current gaze distance of the current LKAECU 16 at the current vehicle speed (the front gaze distance determined most recently and used by the LKAECU 16 to execute temporary LKA control) is read from the database.

  Next, the LKA ECU 16 shortens the picked-up forward gaze distance L by ΔL in step S27. That is, the read forward gaze distance of the current LKA ECU 16 is shortened by a slight adjustment distance. Instead of this, the forward gaze time τ of the current LKA ECU 16 may be shortened by Δτ.

  In step S8, the LKAECU 16 records the data obtained in step S27 (the forward gaze distance L of the LKAECU 16 shortened by ΔL) in the database for each driver and each vehicle speed. That is, the database is updated. Then, the LKA ECU 16 returns to step S1.

  Note that the LKAECU 16 returns to step S1 when the determination is NO.

[B] LKA Operation FIG. 8 is a flowchart of the driving support operation performed by the driving support device, more specifically, the target yaw rate calculation unit and the assist torque calculation unit of the LKA ECU 16. This driving support operation is in accordance with the method described with reference to FIG.

  This flowchart starts when the driver operates the LKA switch 5 to ON.

  In step S31, the LKA ECU 16 identifies the driver, and in step S32, reads the forward gaze distance L at the current vehicle speed of the identified driver from the database.

  Next, in step S33, the LKA ECU 16 calculates a target yaw rate (target turning radius) in consideration of the forward gaze distance L read in step S32 (target yaw rate calculation unit).

  Specifically, the LKA ECU 16 increases the magnitude of the assist torque calculated in step S35 described later as the front gaze distance L is shorter, and the assist torque calculated in step S35 described later as the front gaze distance L is longer. The target yaw rate is calculated so as to reduce the magnitude of.

  More specifically, the LKA ECU 16 calculates a larger target yaw rate (smaller target turning radius) as the driver's forward gaze distance L is shorter in the target yaw rate calculation unit. As a result, the LKA ECU 16 calculates a larger target steering angle as the target yaw rate is larger, and calculates a larger assist torque as the target steering angle is larger. On the contrary, the LKA ECU 16 calculates a target yaw rate (large target turning radius) as the driver's forward gaze distance L is longer in the target yaw rate calculation unit. As a result, the LKA ECU 16 calculates a smaller target steering angle as the target yaw rate is smaller, and calculates a smaller assist torque as the target steering angle is smaller.

  Next, in step S34, the LKA ECU 16 calculates a target steering angle based on the target yaw rate calculated in step S33 (assist torque calculation unit).

  Next, in step S35, the LKA ECU 16 calculates the direction and magnitude of the assist torque based on the target steering angle calculated in step S34 (assist torque calculation unit).

  In step S36, the LKA ECU 16 outputs a signal related to the direction and magnitude of the assist torque calculated in step S35 to the EPS 13 as a command signal. Then, the LKA ECU 16 returns to step S31.

(4) Operation, etc. As described above, the driving support device for the vehicle 1 according to the present embodiment has the camera 11 that detects the lane ahead of the host vehicle 1 and the traveling of the host vehicle 1 in the lane detected by the camera 11. The camera ECU 12 that determines the state (lateral position and attitude angle), the EPS 13 that applies assist torque to the steering device of the host vehicle 1, and the camera 11 that is detected according to the traveling state of the host vehicle 1 determined by the camera ECU 12. The LKA ECU 16 determines the direction and magnitude of the assist torque so that the host vehicle 1 travels in the lane, and has the following characteristic configuration.

  The LKAECU 16 determines the driver's forward gaze distance (steps S17 and S27), and increases the magnitude of the assist torque as the determined forward gaze distance is shorter (steps S33 to S35).

  According to this, the driving of the vehicle 1 capable of executing the LKA control for determining the direction and the magnitude of the assist torque applied to the steering device so that the own vehicle 1 travels in the lane according to the traveling state of the own vehicle 1. In the assist device, as the driver's forward gaze distance is shorter, the magnitude of assist torque applied to the steering device is increased.

  A driver with a short forward gaze distance is a driver who tries to reach the target course early, so for such a driver, the magnitude of the assist torque applied to the steering device is increased, An assist torque in accordance with the driver's will is applied. Conversely, a driver with a long forward gazing distance is a driver who tries to reach the target course slowly, and therefore the assist torque applied to the steering device is reduced for such a driver. As a result, the assist torque is also applied in line with the driver's will. Therefore, in any case, it is suppressed that the driver feels uncomfortable.

  In this embodiment, the LKA switch 5 for switching the LKA ECU 16 between ON and OFF is provided, and the LKA ECU 16 determines the forward gaze distance when the LKA ECU 16 is OFF by the LKA switch 5.

  According to this, when the LKA ECU 16 is OFF, that is, in a state where the assist torque is not applied to the steering device so that the host vehicle 1 travels in the lane according to the travel state of the host vehicle 1, in other words. Since the driver's forward gaze distance is determined without the LKA control intervening, the driver's original forward gaze distance is correctly determined.

  In the present embodiment, the LKA ECU 16 is configured such that when the host vehicle 1 travels toward a predetermined target course in the lane detected by the camera 11, the turning direction of the steering direction performed by the driver (zero cross of the steering torque), If the LKAECU 16 is ON, the timing of turning back in the steering direction (assist torque zero cross) performed by the LKA ECU 16 is compared. If the steering torque zero cross is earlier than the assist torque zero cross, When it is determined that the distance is longer than the most recently determined forward gaze distance (the front gaze distance of LKA ECU 16), and the assist torque zero cross is faster than the steering torque zero cross, the driver's front gaze distance is Determined to be shorter than the determined forward gaze distance (forward gaze distance of LKAECU 16) That.

  According to this, an example of the determination operation performed by the LKA ECU 16 is embodied. According to this, the turning direction of the steering direction actually performed by the driver (zero crossing of the steering torque) and the turning direction of the steering direction that the LKA ECU 16 would have performed if the LKA ECU 16 executed the LKA control ( Assist torque zero cross).

  When the steering torque zero cross is earlier than the assist torque zero cross, the driver's forward gaze distance is the most recently determined forward gaze distance (the forward gaze distance used by the LKA ECU 16 to perform temporary LKA control). ). For example, the situation is as follows. For example, the driver tries to reach the target course slowly, and before the own vehicle 1 reaches the target course, the steering direction is advanced from left turn to right turn or right turn to left turn. This can happen if you switch back to. Therefore, in this case, it can be reasonably determined that the driver's forward gaze distance is long.

  Conversely, when the assist torque zero cross is earlier than the steering torque zero cross, the driver's forward gaze distance is the most recently determined forward gaze distance (the forward gaze used by the LKA ECU 16 to perform temporary LKA control). It is determined that the distance is shorter than (distance). The situation as described above is, for example, that the driver tries to reach the target course early, and after the host vehicle 1 reaches the target course, the steering direction is delayed from the left turn to the right turn or from the right turn to the left turn. This can happen if you switch back to. Therefore, in this case, it can be reasonably determined that the driver's forward gaze distance is short.

  In the present embodiment, the LKA ECU 16 updates and records the determined driver's forward gazing distance (step S8), and uses the recorded driver's forward gazing distance (step S32) to assist the steering device. Direction and size are determined (steps S33 to S35).

  According to this, the LKA ECU 16 determines the direction and the magnitude of the assist torque to be applied to the steering device (steps S33 to S35) using the last (closest) determined forward gaze distance (step S32). The LKA control is always executed in consideration of the latest forward gaze distance.

  In the present embodiment, the LKA ECU 16 finally determines the forward gaze distance of the LKA ECU 16 where the steering torque zero cross and the assist torque zero cross coincide (repetition of steps S1, S12 to S17, S22 to S27, and S8). In the LKA control, such a problem that assist torque in a direction opposite to the steering direction of the driver is applied is avoided.

  Note that the driver's forward gaze distance may be determined by another method different from the method described with reference to FIGS. 4, 5, and 7.

  Further, the driving assistance device (LKA device) of the vehicle 1 according to the present embodiment may be used in combination with, for example, a lane departure warning (LDW) device that warns the vehicle so as not to deviate from the lane by mistake. Good.

1 Vehicle (own vehicle)
2 Steering wheel 3 Steering shaft 4 Wheel 5 LKA switch (switching means)
11 Camera (detection means)
12 Camera ECU (determination means)
13 Electric power steering (auxiliary means)
14 Electric motor 15 EPSECU
16 LKAECU (control means, determination means, recording means)
17 Handle ECU
18 Side slip prevention device ECU
21 Torque sensor 22 Steering angle sensor 23 Inertia sensor 24 Wheel speed sensor

Claims (4)

Detecting means for detecting a lane ahead of the host vehicle;
Determination means for determining the traveling state of the host vehicle in the lane detected by the detection means;
Auxiliary means for applying auxiliary force to the steering device of the host vehicle;
Control means for determining the direction and magnitude of the auxiliary force so that the host vehicle travels in the lane detected by the detection unit according to the traveling state of the host vehicle determined by the determination unit. A driving support device,
A determination means for determining the driver's forward gaze distance is provided,
The vehicle driving support apparatus according to claim 1, wherein the control means increases the magnitude of the auxiliary force as the forward gaze distance determined by the determination means is shorter. The vehicle driving support device according to claim 1,
Switching means for switching between the operation and non-operation of the control means is provided,
The vehicle driving support device according to claim 1, wherein the determination unit determines a forward gaze distance when the control unit is not operated by the switching unit. In the vehicle driving support device according to claim 2,
The determination means includes the timing of turning back in the steering direction performed by the driver while the host vehicle is traveling toward a predetermined target course in the lane detected by the detection means, and the control means is operating. When the former is early, the driver's front gaze distance is determined to be longer than the most recently determined front gaze distance, and the latter When the vehicle is early, it is determined that the driver's forward gaze distance is shorter than the most recently determined forward gaze distance. In the vehicle driving assistance device according to any one of claims 1 to 3,
Recording means for updating and recording the forward gaze distance determined by the determination means is provided,
The driving means for driving a vehicle, wherein the control means uses a forward gaze distance recorded in the recording means.

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