JP5682840B2 - Steering support device - Google Patents

Description

  The present invention relates to a steering assist device, and more particularly to a steering assist device that assists the steering force of a driver of a vehicle.

  2. Description of the Related Art Conventionally, in order to reduce the burden on a driver who drives a vehicle, a steering assist device has been developed that applies an assist torque for assisting the steering force of the driver to the steering according to the traveling state of the vehicle. As one type of such a steering assist device, a steering assist device has been developed that applies an assist torque to the steering so as to maintain the position of the host vehicle in the lane. Such a steering assist device is known as a so-called LKA system (Lane Keeping Assist System).

  An example of the steering assist device as described above is disclosed in Patent Document 1. The steering control device disclosed in Patent Literature 1 calculates a target acceleration in the lateral direction of the vehicle that is necessary for the vehicle to travel in the center of the traveling lane. Then, the steering control device applies an auxiliary torque necessary for the lateral acceleration of the vehicle to reach the target acceleration. When calculating the above-described target acceleration, the steering control device controls the target acceleration by feedforward control based on the curvature of the lane in which the vehicle travels. Further, the steering control device controls the target acceleration by feedback control based on the distance from the center line of the traveling lane of the vehicle to the vehicle. According to such feedforward control and feedback control, the torque of the steering is controlled so that the vehicle travels along the lane in the center of the travel lane.

  According to the control of the steering assist device described above, the auxiliary torque is applied in the direction of returning the vehicle to the center of the lane even when the lane of the vehicle is being changed, that is, when the vehicle is intentionally leaving the current driving lane. May occur. Therefore, in general, the steering assist device as described above stops the generation of the auxiliary torque while the direction indicator mounted on the vehicle is operating.

JP 2009-18626 A

  However, in the conventional control process of the steering assist device, the generation of the auxiliary torque may stop even in a situation where the driver needs the auxiliary torque.

  For example, assume a situation where the vehicle is traveling in a curve section. Normally, while the vehicle is traveling in a curve section, the steering assist device generates an auxiliary torque corresponding to the curve in order to reduce the driver's steering load. Here, when the driver operates the direction indicator to change the lane while traveling in the curve section, the steering assist device stops the auxiliary torque that has been output until that time. When the generation of auxiliary torque stops suddenly, the steering load on the driver may increase rapidly. In such a case, the driver may feel stress due to an increase in the steering load.

  The present invention has been made in view of the above-described problems, and an object of the present invention is to provide a steering assist device that can appropriately reduce a driver's steering load.

  In order to solve the above problems, the present invention employs the following configuration. That is, the first aspect of the present invention is a steering assist device that assists a steering operation of a driver who drives a vehicle, and an assist torque generating means for generating an assist torque that assists the steering force of the driver in the vehicle steering device. And a first torque control means for controlling the auxiliary torque so that the vehicle turns in accordance with the curvature of the traveling lane, and a second torque control for controlling the auxiliary torque so that the traveling position of the vehicle approaches the center line of the traveling lane. Control restraint that suppresses control of auxiliary torque by the second torque control means when it is determined that the vehicle, the lane change determination means that determines whether the vehicle is changing lanes, and the vehicle is changing lanes And a steering assist device.

  According to a second aspect, in the first aspect, from an imaging unit that captures an image in front of the vehicle, a curvature calculation unit that calculates a curvature of the traveling lane of the vehicle based on the image, and a center line of the traveling lane to the vehicle Offset distance calculating means for calculating the offset distance of the vehicle, and deflection angle calculating means for calculating a deflection angle formed by a straight line indicating the traveling direction of the vehicle and a center line of the traveling lane. The auxiliary torque is controlled according to the curvature calculated by the curvature calculating means so as to make a turn according to the curvature, and the second torque control means offsets the auxiliary torque so as to bring the traveling position of the vehicle closer to the center line of the lane. Control is performed according to at least one of the distance and the deflection angle.

  According to a third aspect, in any one of the first and second aspects, a lane change direction determining unit that determines whether the lane change direction of the vehicle is right or left when the vehicle is changing lanes. The auxiliary torque acting direction discriminating means for discriminating whether the turning direction when the vehicle turns by the auxiliary torque by the second torque control means is left or right, and the control suppressing means is that the vehicle is changing lanes The control of the auxiliary torque by the second torque control means is suppressed only when it is determined and the lane change direction does not coincide with the turning direction.

  According to a fourth aspect, in the first aspect, the lane change determination means determines that the vehicle is changing lanes when the direction indicator provided in the vehicle is operated, and the direction indicator is operated. If not, it is determined that the vehicle is not changing lanes.

  In a first aspect, the fifth aspect further comprises steering torque detection means for detecting steering torque by the operation of the driver of the vehicle, and the lane change determination means has a lane change determination means when the steering torque is greater than or equal to a predetermined steering torque threshold value. It is determined that the vehicle is changing lanes, and if the steering torque is less than the steering torque threshold, it is determined that the vehicle is not changing lanes.

  A sixth aspect is characterized in that, in the fifth aspect, steering torque threshold value calculating means for calculating the steering torque threshold value according to the curvature of the traveling lane of the vehicle is further provided.

  A seventh aspect further includes steering angle detection means for detecting the steering angle of the vehicle in the first aspect, and the lane change determination means is configured to change the lane when the steering angle is equal to or greater than a predetermined steering angle threshold. When the steering angle is less than the steering angle threshold, it is determined that the vehicle is not changing lanes.

  An eighth aspect is characterized in that, in the seventh aspect, a steering angle threshold value calculating means for calculating the steering angle threshold value according to the curvature of the traveling lane of the vehicle is further provided.

  In a ninth aspect, in the second aspect, the lane change determination means determines that the vehicle is changing lanes when the offset distance is equal to or greater than a predetermined distance threshold, and the offset distance is less than the distance threshold. It is determined that the vehicle is not changing lanes.

  A tenth aspect further includes, in the ninth aspect, lane width calculating means for calculating the width of the traveling lane, and threshold calculating means for calculating a distance threshold according to the width of the traveling lane of the vehicle. To do.

  In an eleventh aspect, in the first aspect, the lane change determination means determines that the vehicle is changing lanes when the hazard lamp provided in the vehicle is operated, and the hazard lamp is not operated. In this case, it is determined that the vehicle is not changing lanes.

  In a twelfth aspect according to the second aspect, the second torque control means controls the auxiliary torque so that the auxiliary torque increases as the value calculated by multiplying the offset distance and the deflection angle by a predetermined gain value increases. Then, the control suppression means changes the gain value to a smaller value when it is determined that the vehicle is changing lanes than when it is determined that the vehicle is not changing lanes. It is characterized in that the control of the auxiliary torque by is suppressed.

  According to a thirteenth aspect, in the second aspect, the second torque control means controls the auxiliary torque so that the auxiliary torque increases as the offset distance and the deflection angle increase, and the control suppression means changes the lane of the vehicle. When it is determined that the vehicle is in the second state, the offset distance and the deflection angle value input to the second torque control means are corrected to values smaller than those determined when the vehicle is not changing the lane. The control of the auxiliary torque by the torque control means is suppressed.

  According to the first aspect, the driver's steering load can be appropriately reduced. Specifically, according to the first aspect, when it is determined that the vehicle is changing lanes, the control of the auxiliary torque for bringing the traveling position of the vehicle closer to the center line of the traveling lane is suppressed. Only the control of the auxiliary torque for making a turn according to the curvature is executed. Therefore, when the driver intentionally leaves the current travel lane when changing lanes, the generation of auxiliary torque that attempts to return the vehicle to the center line of the travel lane is suppressed. On the other hand, the auxiliary torque required for curve driving and the like is continuously generated before and after the lane change. Therefore, the driver can comfortably operate the vehicle with a small steering load.

  According to the second aspect, the auxiliary torque can be appropriately controlled based on the shape of the traveling lane and the relative position of the vehicle with respect to the center line of the traveling lane.

  According to the third aspect, while the vehicle is changing lanes, the control of the second torque control means is suppressed only when the direction in which the auxiliary torque is applied by the second torque control means differs from the lane change direction of the vehicle. Is done. In other words, even if the vehicle is changing lanes, the control of the second torque control means is normal as long as the direction of operation of the auxiliary torque by the second torque control means is the same as the lane change direction of the vehicle. Executed. In other words, the auxiliary torque increase control by the second torque control means is possible for the direction of action along the driver's intention. Therefore, for example, when the vehicle moves in a direction contrary to the driver's intention due to a disturbance such as a cross wind, the auxiliary torque is increased in the direction intended by the driver by the second torque control means as well as the first torque control means. Can do. Therefore, the driver can perform the steering operation in the intended direction with a smaller steering load than when the control of the second torque control unit is suppressed.

  According to the fourth aspect, whether or not the vehicle is changing lanes can be determined by a simple process depending on whether or not the direction indicator is operated.

  According to the fifth aspect, whether or not the vehicle is changing lanes can be determined by a simple process according to the magnitude of the steering torque.

  According to the sixth aspect, the steering torque threshold value can be set to an appropriate value according to the curvature of the traveling lane. Therefore, it can be accurately determined whether or not the vehicle is changing lanes.

  According to the seventh aspect, whether or not the vehicle is changing lanes can be determined by a simple process according to the magnitude of the steering angle.

  According to the eighth aspect, the steering angle threshold value can be set to an appropriate value according to the curvature of the travel lane. Therefore, it can be accurately determined whether or not the vehicle is changing lanes.

  According to the ninth aspect, whether or not the vehicle is changing the lane can be determined by a simple process according to the offset distance from the center line of the traveling lane to the vehicle.

  According to the tenth aspect, the offset distance threshold can be set to an appropriate value according to the width of the traveling lane. Therefore, it can be accurately determined whether or not the vehicle is changing lanes.

  According to the eleventh aspect, it is possible to suppress the control of the auxiliary torque by the second torque control means while the hazard lamp is being operated. For example, in an emergency, a driver may turn on a hazard lamp to move a vehicle to the shoulder. In such a case, according to the eleventh aspect, since the generation of auxiliary torque that returns the vehicle to the center of the lane is suppressed, the driver can easily operate the vehicle.

  According to the twelfth aspect, the control of the auxiliary torque by the second torque control means can be easily suppressed by a simple process of changing the gain value. In addition, it is possible to arbitrarily adjust the degree of suppression of the control of the second torque control means by arbitrarily adjusting the magnitude of the gain value.

  According to the thirteenth aspect, when the second torque control means determines the value of the auxiliary torque, the assistance by the second torque control means is performed by a simple process of correcting the values of various parameters (offset distance and deflection angle). Torque control can be easily suppressed.

An example of a block diagram showing a configuration of a steering assist device according to the first embodiment The figure which shows the definition of the various parameters used for control of lane keeping assistance ECU50 An example of a flowchart showing details of processing executed by the lane keeping assist ECU 50 according to the first embodiment An example of a control block diagram showing the contents of arithmetic processing executed by the lane keeping assist ECU 50 according to the first embodiment The figure which shows the driving locus of the vehicle 100 which changes lanes in a curve area The figure which shows the value of the auxiliary torque TA which a steering assistance device outputs The figure which shows the value of steering torque TM which a driver applies to steering An example of a flowchart showing details of processing executed by the lane keeping assist ECU 50 according to the second embodiment An example of a flowchart executed by the lane keeping assist ECU 50 according to the third embodiment An example of a flowchart showing a gain setting process executed by the lane keeping assist ECU 50 according to the third embodiment

(First embodiment)
Hereinafter, a steering assist device 1 according to a first embodiment of the present invention will be described. The steering assist device 1 is a device that assists the driver's steering force. In the embodiment described below, an example in which the steering assist device 1 is mounted on the vehicle 100 will be described.

  First, the configuration of the steering assist device will be described with reference to FIG. FIG. 1 is an example of a block diagram illustrating the configuration of the steering assist device according to the first embodiment. As shown in FIG. 1, the steering assist device includes a front monitoring camera 10, an image processing ECU 11, a vehicle speed sensor 20, a yaw rate sensor 30, a direction indicator 40, a lane keeping assist ECU 50, and a steering device 60.

  The front monitoring camera 10 is an imaging device for an image in front of the vehicle 100 (hereinafter referred to as a front image). The front monitoring camera 10 is typically an imaging device including an image sensor such as a CCD (Charge Coupled Device) sensor or a CMOS (Complementary Metal Oxide Semiconductor) sensor. When the front monitoring camera 10 captures a front image, the front monitoring camera 10 transmits data indicating the front image to the image processing ECU 11.

  The image processing ECU 11 is typically an image processing device including an information processing device such as a CPU (Central Processing Unit), a storage device such as a memory, and an interface circuit. The image processing ECU 11 calculates the curvature R of the lane in which the vehicle 100 is currently traveling (hereinafter referred to as a traveling lane) based on the front image received from the front monitoring camera 10. Note that the image processing ECU 11 may calculate the road curvature R using any conventionally known method. When the curvature R is calculated, the image processing ECU 11 transmits data indicating the curvature R to the lane keeping assist ECU 50.

  The vehicle speed sensor 20 is a sensor device that detects the vehicle speed V of the vehicle 100. The vehicle speed sensor 20 may detect the vehicle speed V using any conventionally known method. When the vehicle speed sensor 20 detects the vehicle speed V, the vehicle speed sensor 20 transmits data indicating the vehicle speed V to the lane keeping assist ECU 50.

  The yaw rate sensor 30 is a sensor device that detects the yaw rate ω of the vehicle 100. The yaw rate sensor 30 may detect the yaw rate ω using any conventionally known method. When detecting the yaw rate ω, the yaw rate sensor 30 transmits data indicating the yaw rate ω to the lane keeping assist ECU 50. As shown in FIG. 2, the value of the yaw rate ω is represented by a positive value for leftward rotation and a negative value for rightward rotation. FIG. 2 is a diagram illustrating definitions of various parameters used for control of the lane keeping assist ECU 50.

  The direction indicator 40 is a device that receives the operation of the driver of the vehicle 100 and displays the traveling direction of the vehicle 100 outside the vehicle according to the operation. The direction indicator 40 includes an operation lever that receives the operation of the driver. The operation lever can be moved to any one of the left instruction position, the original position, and the right instruction position by an operation of the driver, and is normally disposed at the original position. The direction indicator 40 sends an indicator operation signal indicating that the direction indicator 40 is being operated by the driver while the operation lever is moved to either the left indication position or the right indication position by the driver. It transmits to maintenance support ECU50.

  The lane keeping assist ECU 50 is typically a processing device including an information processing device such as a CPU, a storage device such as a memory, an interface circuit, and the like. The lane keeping assist ECU 50 calculates a target lateral acceleration Gt necessary for the vehicle 100 to keep traveling along the traveling lane based on the information input from each of the above devices. Then, the lane keeping assist ECU 50 transmits data indicating the calculated target lateral acceleration Gt to the steering control ECU 62 included in the steering device 60. Details of processing of the lane keeping assist ECU 50 will be described later with reference to FIG.

  The steering device 60 is a device that changes the traveling direction of the vehicle 100 in accordance with the driver's steering operation and control information from the lane keeping assist ECU 50. The steering device 60 includes a steering sensor 61, a steering control ECU 62, and a steering actuator 63.

  The steering sensor 61 is a sensor device that detects information related to a driver's steering operation. The information detected by the steering sensor 61 includes the steering torque TM applied to the steering by the driver's operation. The steering sensor 61 outputs information such as the detected steering torque TM to the steering control ECU 62. The steering control ECU 62 is typically a processing device including an information processing device such as a CPU, a storage device such as a memory, and an interface circuit. The steering control ECU 62 controls the steering actuator 63 in accordance with information received from the lane keeping assist ECU 50 and the steering sensor 61. Specifically, the steering control ECU 62 calculates a target steering torque amount necessary for the lateral acceleration of the vehicle 100 to satisfy the target lateral acceleration Gt. Then, the steering control ECU 62 calculates the value of the auxiliary torque TA according to the target steering torque amount. The steering actuator 63 is typically an electric motor that applies an auxiliary torque TA to a steering shaft (not shown) of the vehicle 100.

  Next, a process executed by the lane keeping assist ECU 50 will be described with reference to FIG. FIG. 3 is an example of a flowchart showing details of processing executed by the lane keeping assist ECU 50 according to the first embodiment. The lane keeping assist ECU 50 executes the process shown in FIG. 3 when the IG power supply of the vehicle 100 is set to the on state. When the lane keeping assist ECU 50 starts the process of the flowchart of FIG. 3, first, the lane keeping assist ECU 50 executes the process of step A1.

  In step A1, the lane keeping assist ECU 50 determines whether or not the LKA system is on. The LKA system is a system that controls the traveling of the vehicle 100 to maintain the traveling lane. The steering assist device 1 according to the present invention operates as a part of the LKA system. The operation state of the LKA system can be arbitrarily switched by the driver operating an interface (not shown) such as a switch mounted on the vehicle 100. If the lane keeping assist ECU 50 determines that the LKA system is on, the lane keeping assist ECU 50 advances the process to step A2. On the other hand, if the lane keeping assist ECU 50 determines that the LKA system is not on, the lane keeping assist ECU 50 advances the process to step A8.

  In step A2, the lane keeping assist ECU 50 calculates the FF control acceleration Gff. Specifically, as shown in FIG. 4, the lane keeping assist ECU 50 first acquires the curvature R of the travel lane from the image processing ECU 11 and the vehicle speed V from the vehicle speed sensor 20. Then, the lane keeping assist ECU 50 calculates the FF control acceleration Gff by sequentially multiplying the curvature R by the square of the vehicle speed V and the gain value kR. That is, the FF control acceleration Gff is a value indicating the lateral target acceleration necessary for the vehicle 100 to continue traveling along the curvature of the current traveling lane. FIG. 4 is an example of a control block diagram showing the contents of the arithmetic processing executed by the lane keeping assist ECU 50. The gain value kR is an arbitrary constant stored in advance in the lane keeping assist ECU 50. When the lane keeping assist ECU 50 completes the process of step A2, the process proceeds to step A3.

  In step A3, the lane keeping assist ECU 50 calculates the FB control acceleration Gfb. Specifically, as shown in FIG. 4, first, the lane keeping assist ECU 50 acquires the yaw rate ω from the yaw rate sensor 30. Next, the lane keeping assist ECU 50 calculates the time integral value of the yaw rate ω as the yaw angle θ of the vehicle 100. As shown in FIG. 2, the yaw angle θ is a deflection angle of an axis CC indicating the traveling direction of the vehicle 100 with respect to the center line LC of the traveling lane. Further, the lane keeping assist ECU 50 calculates the offset distance D by time integration of a value obtained by multiplying the yaw angle θ by the vehicle speed V. As shown in FIG. 2, the offset distance D is a distance from the center line LC of the traveling lane to the vehicle 100. The lane keeping assist ECU 50 calculates the FB control acceleration Gfb by adding a value obtained by multiplying the yaw angle θ by the gain value kθ and the offset distance D by the gain value kD. That is, the FB control acceleration Gfb is a value indicating the target acceleration in the lateral direction necessary for returning the vehicle 100 to the center of the traveling lane. The gain value kθ and the gain value kD are arbitrary constants stored in advance in the lane keeping assist ECU 50. When the lane keeping assist ECU 50 completes the process of step A3, the process proceeds to step A4.

  In the process of step A3, the example in which the lane keeping assist ECU 50 calculates the deflection angle θ based on the yaw rate ω has been described. However, the lane keeping assist ECU 50 may calculate the deflection angle θ based on the front image. I do not care. In the above description, the offset distance D is calculated based on the deflection angle θ and the vehicle speed V. However, the lane keeping assist ECU 50 may calculate the offset distance D based on the front image. Further, the lane keeping assist ECU 50 may calculate the deflection angle θ and the offset distance D using any conventionally known method, not limited to the above.

  In addition, the order of the processes in step A2 and step A3 may be reversed. In addition, when the lane keeping assist ECU 50 can execute the processes of step A2 and step A3 at the same time, these processes may be executed at the same time.

In step A4, the lane keeping assist ECU 50 determines whether or not the vehicle 100 is changing lanes. Specifically, the lane keeping assist ECU 50 determines whether or not the direction indicator 40 is operated based on the indicator operation signal transmitted from the direction indicator 40. When the lane keeping assist ECU 50 receives the indicator operation signal, the lane keeping assist ECU 50 determines that the vehicle 100 is changing the lane, and advances the process to step A6 . On the other hand, when the lane keeping assist ECU 50 has not received the indicator operation signal, the lane keeping assist ECU 50 determines that the vehicle 100 is not changing the lane and advances the process to step A5 .

  In step A5, the lane keeping assist ECU 50 calculates a value obtained by adding the FF control acceleration Gff and the FB control acceleration Gfb as the value of the target lateral acceleration Gt. When the lane keeping assist ECU 50 completes the process of step A5, the process proceeds to step A7.

  In step A6, the lane keeping assist ECU 50 sets the value of the FF control acceleration Gff as the value of the target lateral acceleration Gt as it is. When the lane keeping assist ECU 50 completes the process of step A6, the process proceeds to step A7.

  In step A7, the lane keeping assist ECU 50 outputs the target lateral acceleration Gt to the steering control ECU 62. When the lane keeping assist ECU 50 completes the process of step A7, the process proceeds to step A8.

  In step A8, the lane keeping assist ECU 50 determines whether or not the IG power supply of the vehicle 100 is set to an off state. When the lane keeping assist ECU 50 determines that the IG power source is set to the off state, the lane keeping assist ECU 50 completes the process of the flowchart of FIG. On the other hand, if the lane keeping assist ECU 50 determines that the IG power supply is on, the lane keeping assist ECU 50 returns the process to step A1.

  According to the processing of the lane keeping assist ECU 50 shown in FIGS. 3 and 4 described above, the lane keeping assist ECU 50 calculates the target lateral acceleration Gt based on the FF control acceleration Gff, so that the vehicle 100 has the curvature R of the traveling lane. The auxiliary torque TA is controlled so that the vehicle travels according to the turning. Further, the lane keeping assist ECU 50 calculates the target lateral acceleration Gt based on the FB control acceleration Gfb, thereby controlling the auxiliary torque TA so as to bring the traveling position of the vehicle 100 closer to the center line of the traveling lane. Hereinafter, the control of the auxiliary torque TA based on the FF control acceleration Gff is referred to as feedforward control. Further, the control of the auxiliary torque TA based on the FB control acceleration Gfb is referred to as feedback control.

  When the vehicle 100 has not changed the lane, the lane keeping assist ECU 50 calculates the target lateral acceleration Gt based on both the FB control acceleration Gfb and the FF control acceleration Gff. That is, the lane keeping assist ECU 50 controls the auxiliary torque TA by both feedback control and feedforward control while the vehicle 100 is not changing lanes. On the other hand, the lane keeping assist ECU 50 calculates the target lateral acceleration Gt based only on the FF control acceleration Gff without considering the FB control acceleration Gfb while the vehicle 100 is changing lanes. That is, the lane keeping assist ECU 50 stops the control of the auxiliary torque TA by the feedback control while the vehicle 100 is changing the lane, and controls the auxiliary torque TA only by the feedforward control.

  According to such a control process, the feedback control is stopped while the vehicle 100 is changing lanes, so that auxiliary torque is not generated in a direction in which the vehicle 100 is pulled back to the original lane. On the other hand, since the feedforward control is executed even when the vehicle 100 is changing lanes, auxiliary torque necessary for curve driving is generated. Therefore, according to the steering assist device 1, the necessary auxiliary torque TA can be generated in the steering device 60 without hindering the steering of the driver.

  Next, how the steering assist device 1 generates an appropriate auxiliary torque TA and the driver's steering load is preferably reduced will be described in detail. Hereinafter, a situation where the vehicle 100 is changing lanes in a curve section will be described as an example. FIG. 5 is a diagram illustrating a travel locus of the vehicle 100 that changes lanes in a curve section.

  In FIG. 5, a position P1, a position P2, a position P3, and a position P4 indicate positions of the vehicle 100 at time t1, time t2, time t3, and time t4. At time t1, the vehicle 100 enters the curve section and starts running on the curve. Next, at time t2, the vehicle 100 starts a lane change from the outer lane of the curve to the inner lane. Next, at time t3, the vehicle 100 completes the lane change. Then, the vehicle travels on a straight road through the curve section at time t4.

  Changes in the auxiliary torque TA and the driver's steering load when the vehicle 100 travels on the route shown in FIG. 5 will be described with reference to FIGS. 6 and 7. FIG. 6 is a diagram illustrating the value of the auxiliary torque TA output from the steering assist device. FIG. 7 is a diagram showing the value of the steering torque TM applied to the steering by the driver. The value of the steering torque TM shown in FIG. 7 is considered to be proportional to the steering load of the driver.

  In FIG. 6, the value indicated by the dotted line is the value of the assist torque output by the conventional steering assist device. In FIG. 7, the value indicated by the dotted line is the value of the steering torque applied to the steering wheel by the driver who receives assistance from the conventional steering assistance device. As described above, the conventional steering assist device stops the control for generating the auxiliary torque while the vehicle is changing the lane. Therefore, as shown in FIG. 6, the value of the auxiliary torque is small from time t2 to time t3. As a result, as shown in FIG. 7, the steering torque that the driver applies to the steering is abruptly increased from time t2 to time t3.

  On the other hand, according to the steering assist device 1 according to the present invention, while the vehicle 100 changes lanes, the control of the auxiliary torque TA according to the yaw angle θ and the offset distance D is suppressed, but according to the curvature R. The control of the auxiliary torque TA is continuously executed. Therefore, as shown in FIG. 6, the value of the auxiliary torque TA is not extremely reduced even between the time t2 and the time t3. In FIG. 6, the value indicated by the solid line is the value of the auxiliary torque TA output by the steering assist device 1. Therefore, as shown in FIG. 7, the steering torque TM applied to the steering by the driver does not increase from time t2 to time t3. In FIG. 7, the value indicated by the solid line is the value of the steering torque TM applied to the steering by the driver who receives assistance from the steering assistance device 1. That is, according to the steering assist device 1, the driver can operate the vehicle 100 with a steering load smaller than that in the prior art.

  As described above, according to the steering assist device 1 according to the first embodiment of the present invention, it is possible to output necessary auxiliary torque while suppressing generation of auxiliary torque that hinders lane change. That is, according to the steering assist device 1, the steering load on the driver can be appropriately reduced.

(Second Embodiment)
In the first embodiment, the example in which the lane keeping assist ECU 50 always stops the control of the auxiliary torque TA by feedback control while the vehicle 100 is changing the lane has been described. The feedback control may be stopped only when 100 is changing the lane and it is determined that the assist torque by the feedback control hinders the driver's operation. Specifically, the lane keeping assist ECU 50 determines that the direction in which the vehicle 100 turns by the assist torque by the feedback control, that is, the direction in which the FB control acceleration Gfb is applied differs from the lane change direction of the vehicle 100, It is determined that the operation of the driver is hindered.

  Hereinafter, a steering assist device according to the second embodiment will be described. The configuration of the steering assist device according to the second embodiment is the same as that of the first embodiment except for the processing executed by the lane keeping assist ECU 50 and the information output by the direction indicator 40. A detailed description of the configuration is omitted.

  The direction indicator 40 according to the second embodiment transmits an instruction direction signal indicating which direction is left or right to the lane keeping assist ECU 50 together with the above-mentioned indicator operation signal while the operation lever is being operated. .

  Next, processing executed by the lane keeping assist ECU 50 according to the second embodiment will be described with reference to FIG. FIG. 8 is an example of a flowchart showing details of processing executed by the lane keeping assist ECU 50 according to the second embodiment. In FIG. 8, steps that perform the same processing as in the first embodiment are given the same reference numerals, and detailed descriptions thereof are omitted. When the lane keeping assist ECU 50 according to the second embodiment starts the process of the flowchart of FIG. 8, the lane keeping assist ECU 50 executes the processes from step A1 to step A3 as in the first embodiment.

  If the lane keeping assist ECU 50 according to the second embodiment determines in step A4 that the vehicle 100 is changing lanes, the lane keeping assist ECU 50 advances the process to step B1. On the other hand, if it is determined in step A4 that the vehicle 100 is not changing the lane, the lane keeping assist ECU 50 advances the process to step B3.

  In step B1, the lane keeping assist ECU 50 determines whether or not the lane change direction of the vehicle 100 is the left. Specifically, the lane keeping assist ECU 50 determines whether or not an instruction direction signal indicating the left direction is received from the direction indicator 40. If the lane keeping assist ECU 50 has received an instruction direction signal indicating the left direction from the direction indicator 40, the lane keeping assist ECU 50 determines that the lane change direction of the vehicle 100 is left, and advances the process to step B2. On the other hand, if the lane keeping assist ECU 50 has not received the pointing direction signal indicating the left direction from the direction indicator 40, the lane keeping assist ECU 50 determines that the lane change direction of the vehicle 100 is the right, and advances the process to step B3.

  In step B2, the lane keeping assist ECU 50 determines whether or not the acting direction of the FB control acceleration Gfb of the vehicle 100 is the left. Specifically, the lane keeping assist ECU 50 determines whether or not the value of the FB control acceleration Gfb is a positive value. If the value of the FB control acceleration Gfb is a positive value, the lane keeping assist ECU 50 determines that the direction of action of the FB control acceleration Gfb of the vehicle 100 is left, and advances the process to Step A5. On the other hand, if the value of the FB control acceleration Gfb is a negative value, the lane keeping assist ECU 50 determines that the direction of action of the FB control acceleration Gfb of the vehicle 100 is right, and advances the process to Step A6.

  In step B3, the lane keeping assist ECU 50 determines whether or not the direction of action of the FB control acceleration Gfb of the vehicle 100 is right. Specifically, the lane keeping assist ECU 50 determines whether or not the value of the FB control acceleration Gfb is a negative value. If the value of the FB control acceleration Gfb is a negative value, the lane keeping assist ECU 50 determines that the direction of action of the FB control acceleration Gfb of the vehicle 100 is right, and advances the process to Step A5. On the other hand, if the value of the FB control acceleration Gfb is a positive value, the lane keeping assist ECU 50 determines that the direction of action of the FB control acceleration Gfb of the vehicle 100 is left, and advances the process to Step A6.

  The lane keeping assist ECU 50 according to the second embodiment performs the same processing as in the first embodiment with respect to the processing from step A5 to step A8.

  As described above, the lane keeping assist ECU 50 according to the second embodiment performs the FF control when the vehicle 100 is changing lanes and the lane change direction of the vehicle 100 and the action direction of the acceleration Gfb are the same in the left and right directions. A value obtained by adding the acceleration Gff and the FB control acceleration Gfb is set as the value of the target lateral acceleration Gt. That is, the lane keeping assist ECU 50 stops the control of the auxiliary torque TA by feedback control when the vehicle 100 is changing lanes and the lane change direction and the direction of action of the acceleration Gfb are different from each other on the left and right. The auxiliary torque TA is controlled only by the control.

  On the other hand, when the vehicle 100 is changing lanes and the lane change direction of the vehicle 100 and the direction of action of the acceleration Gfb are different from each other, the lane keeping assist ECU 50 uses the value of the FF control acceleration Gff as it is as the target lateral acceleration Gt. Set as a value. That is, the lane keeping assist ECU 50 controls the auxiliary torque TA by feedforward control and feedback control when the vehicle 100 is changing lanes and the lane change direction and the direction of action of the acceleration Gfb are the same in the left and right directions. .

  According to the processing of the lane keeping assist ECU 50 according to the second embodiment, while the vehicle 100 is changing lanes, the feedforward control is performed when the acting direction of the auxiliary torque by the feedback control does not follow the driver's intention. The control of the auxiliary torque TA by is stopped. Therefore, according to the steering assist device according to the second embodiment, as in the steering assist device according to the first embodiment, the assist necessary for curve traveling or the like is stopped while the generation of the assist torque that hinders the lane change is stopped. Torque can be output.

  Further, according to the processing of the lane keeping assist ECU 50, an increase in auxiliary torque by feedback control can be permitted even in the lane change direction, that is, the direction along the driver's intention, even during the lane change. Therefore, for example, when the vehicle 100 is pushed back to the original travel lane due to a disturbance such as a crosswind at the time of lane change, the auxiliary torque in the lane change direction can be increased not only by feedforward control but also by feedback control. . Therefore, according to the steering assist device according to the second embodiment, the driver of the vehicle 100 can perform the lane change operation of the vehicle 100 with a smaller steering load in the above situation.

  In the second embodiment, the example in which the lane keeping assist ECU 50 determines the lane change direction of the vehicle 100 based on the instruction direction signal has been described. However, the lane keeping assist ECU 50 may be determined by any other method. You may determine the lane change direction. For example, the lane keeping assist ECU 50 may determine the lane change direction of the vehicle 100 based on the steering angle or steering torque of the vehicle 100.

(Third embodiment)
In the first and second embodiments, the example in which the lane keeping assist ECU 50 stops the feedback control during the lane change of the vehicle 100 has been described, but the lane keeping assist ECU 50 does not completely stop the feedback control. You may perform control which suppresses control. Specifically, the lane keeping assist ECU 50 may suppress the control by controlling the gain value kD and the gain value kθ related to the feedback control.

  Hereinafter, a steering assist device according to a third embodiment will be described. Note that the configuration of the steering assist device according to the third embodiment is the same as that of the above-described first embodiment except for the processing executed by the lane keeping assist ECU 50, and a detailed description thereof will be omitted.

  FIG. 9 is an example of a flowchart showing details of processing executed by the lane keeping assist ECU 50 according to the third embodiment. The lane keeping assist ECU 50 executes the process shown in FIG. 9 when the IG power supply of the vehicle 100 is set to the on state. When the lane keeping assist ECU 50 starts the process of the flowchart of FIG.

  In Step C1, the lane keeping assist ECU 50 determines whether or not the LKA system is on in the same manner as in Step A1 described above. If the lane keeping assist ECU 50 determines that the LKA system is on, the lane keeping assist ECU 50 advances the process to step C2. On the other hand, if the lane keeping assist ECU 50 determines that the LKA system is not on, the lane keeping assist ECU 50 advances the process to step C7.

  In step C2, the lane keeping assist ECU 50 executes a gain setting process. The gain setting process is a process for controlling the gain value kD and the gain value kθ related to feedback control. The details of the gain setting process will be described below with reference to FIG. FIG. 10 is an example of a flowchart showing a gain setting process executed by the lane keeping assist ECU 50 according to the third embodiment. When the lane keeping assist ECU 50 starts the gain setting process, the lane keeping assist ECU 50 first executes the process of step C21.

  In step C21, the lane keeping assist ECU 50 determines whether or not the vehicle 100 is changing lanes in the same manner as in step A4. If the lane keeping assist ECU 50 determines that the vehicle 100 is changing lanes, the lane keeping assist ECU 50 advances the process to step C22. On the other hand, if the lane keeping assist ECU 50 has not received the indicator operation signal, the lane keeping assist ECU 50 determines that the vehicle 100 is not changing the lane and advances the process to step C24.

  In step C22, the lane keeping assist ECU 50 sets the gain value kθ to the normal value α1. The normal value α1 is a predetermined arbitrary constant. The normal value α1 is stored in advance in the storage device of the lane keeping assist ECU 50. When the lane keeping assist ECU 50 completes the process of step C22, the process proceeds to step C23.

  In step C23, the lane keeping assist ECU 50 sets the gain value kD to the normal value β1. The normal value β1 is a predetermined arbitrary constant. The normal value β1 is stored in advance in the storage device of the lane keeping assist ECU 50. When the lane keeping assist ECU 50 completes the process of step C23, the lane keeping assist ECU 50 completes the gain setting process and advances the process to step C3 of FIG.

  In step C24, the lane keeping assist ECU 50 sets the gain value kθ to the correction value α2. The correction value α2 is an arbitrary constant smaller than the normal value α1. The correction value α2 is stored in advance in the storage device of the lane keeping assist ECU 50. When the lane keeping assist ECU 50 completes the process of step C24, the process proceeds to step C25.

  In step C25, the lane keeping assist ECU 50 sets the gain value kD to the correction value β2. The correction value β2 is an arbitrary constant smaller than the normal value β1. The correction value β2 is stored in advance in the storage device of the lane keeping assist ECU 50. When the lane keeping assist ECU 50 completes the process of step C25, the lane keeping assist ECU 50 completes the gain setting process and advances the process to step C3 of FIG.

  In step C3, the lane keeping assist ECU 50 calculates the FF control acceleration Gff in the same manner as in step A2. When the lane keeping assist ECU 50 completes the process of step C3, the process proceeds to step C4.

  In step C4, the lane keeping assist ECU 50 calculates the FB control acceleration Gfb in the same manner as in step A3. When the lane keeping assist ECU 50 completes the process of step C4, the process proceeds to step C5.

  Note that the order of the processes in steps C3 and C4 may be reversed. Further, when the lane keeping assist ECU 50 can execute the processes of the above steps C3 and C4 at the same time, these processes may be executed at the same time.

  In step C5, the lane keeping assist ECU 50 sets a value obtained by adding the FF control acceleration Gff and the FB control acceleration Gfb as the value of the target lateral acceleration Gt. When the lane keeping assist ECU 50 completes the process of step C5, the process proceeds to step C6.

  In step C6, the lane keeping assist ECU 50 outputs the target lateral acceleration Gt to the steering control ECU 62. When the lane keeping assist ECU 50 completes the process of step C6, the process proceeds to step C7.

  In step C7, the lane keeping assist ECU 50 determines whether or not the IG power supply of the vehicle 100 is set to an off state. When the lane keeping assist ECU 50 determines that the IG power source is set to the off state, the lane keeping assist ECU 50 completes the process of the flowchart of FIG. On the other hand, if the lane keeping assist ECU 50 determines that the IG power source is on, the lane keeping assist ECU 50 returns the process to step C1.

  According to the processing of the lane keeping assist ECU 50 according to the third embodiment, the values of the gain value kD and the gain value kθ are larger while the vehicle 100 is changing lanes than when the vehicle 100 is not changing lanes. Set to a small value. That is, while the vehicle 100 is changing lanes, an increase in auxiliary torque due to feedback control can be suppressed. Therefore, according to the steering assist device according to the third embodiment, as with the steering assist device according to the first embodiment, while the vehicle 100 is changing the lane, the generation of the auxiliary torque that prevents the lane change is generated. Necessary auxiliary torque TA can be output while suppressing.

  Further, according to the steering assist device according to the third embodiment, the degree of suppression of feedback control can be arbitrarily adjusted by changing the set values of the correction value α2 and the correction value β2. When the correction value α2 and the correction value β2 are each set to 0 in advance, the value of the FB control acceleration Gfb is also 0 while the vehicle 100 is changing lanes. That is, when the correction value α2 and the correction value β2 are each set to 0 in advance, the control of the auxiliary torque TA by the feedback control can be substantially stopped while the vehicle 100 is changing the lane.

  In the third embodiment, the example in which the control of the auxiliary torque TA by the feedback control is suppressed by changing the gain value kD and the gain value kθ has been described. However, the lane keeping assist ECU 50 performs the feedback control. The increase / decrease control of the auxiliary torque TA may be suppressed by decreasing the values of the yaw angle θ and the offset distance D, which are input values.

  In each of the above embodiments, an example has been described in which the lane keeping assist ECU 50 determines whether or not the vehicle 100 is changing lanes depending on whether or not the direction indicator 40 is operated. The support ECU 50 may determine whether or not the vehicle 100 is changing lanes by another method.

  For example, the lane keeping assist ECU 50 may determine whether or not the vehicle 100 is changing lanes based on the magnitude of the driver's steering torque TM. Specifically, the lane keeping assist ECU 50 determines whether or not the value of the steering torque TM acquired from the steering sensor 61 is greater than or equal to the steering torque threshold value TMth in Step A4 and Step C21 described above. The lane keeping assist ECU 50 determines that the vehicle 100 is changing lanes when the value of the steering torque TM is equal to or greater than the steering torque threshold TMth. On the other hand, when the value of the steering torque TM is less than the steering torque threshold value TMth, the lane keeping assist ECU 50 determines that the vehicle 100 is not changing the lane.

  Note that the value of the steering torque threshold value TMth is preferably changed as needed by the lane keeping assist ECU 50 according to the value of the curvature R. Specifically, when the lane keeping assist ECU 50 starts the processes of step A4 and step C21, first, a value obtained by multiplying the curvature R by a predetermined coefficient is calculated as the steering torque threshold value TMth, and then the determination process described above is performed. Good to run. The steering torque TM is a relatively large value not only when the vehicle 100 is changing lanes but also during curve driving. Here, if the steering torque threshold value TMth is set according to the curvature R as described above, the vehicle 100 is changing lanes only when the steering torque TM that is greater than or equal to the steering torque necessary for curve traveling is generated. Can be estimated. That is, according to the processing of the lane keeping assist ECU 50, it is possible to accurately determine whether or not the vehicle 100 is changing lanes based on the steering torque TM.

  The lane keeping assist ECU 50 may determine whether the vehicle 100 is changing lanes based on the magnitude of the steering angle φ of the vehicle 100. Specifically, the lane keeping assist ECU 50 determines whether or not the value of the steering angle φ acquired from the steering sensor 61 is greater than or equal to the steering angle threshold φth in the above-described step A4 and step C21. The lane keeping assist ECU 50 determines that the vehicle 100 is changing lanes when the value of the steering angle φ is equal to or greater than the steering angle threshold φth. On the other hand, if the value of the steering angle φ is less than the steering angle threshold value φth, the lane keeping assist ECU 50 determines that the vehicle 100 is not changing the lane.

  Note that the value of the steering angle threshold φth is preferably changed as needed by the lane keeping assist ECU 50 according to the value of the curvature R. Specifically, when the lane keeping assist ECU 50 starts the processes of step A4 and step C21, first, a value obtained by multiplying the curvature R by a predetermined coefficient is calculated as the steering angle threshold φth, and then the above-described determination process. Good to run. The steering angle φ is a relatively large value not only when the vehicle 100 is changing lanes but also during curve driving. Here, if the steering angle threshold φth is set according to the curvature R as described above, it is estimated that the vehicle 100 is changing lanes only when steering is performed at a steering angle greater than that required for curve traveling. be able to. That is, according to the processing of the lane keeping assist ECU 50, it is possible to accurately determine whether or not the vehicle 100 is changing lanes based on the steering angle φ.

  The lane keeping assist ECU 50 may determine whether the vehicle 100 is changing lanes based on the offset distance D. Specifically, the lane keeping assist ECU 50 determines whether or not the value of the offset distance D is greater than or equal to the offset distance threshold value Dth in Step A4 and Step C21 described above. The lane keeping assist ECU 50 determines that the vehicle 100 is changing lanes when the value of the offset distance D is equal to or greater than the offset distance threshold Dth. On the other hand, when the value of the offset distance D is less than the offset distance threshold Dth, the lane keeping assist ECU 50 determines that the vehicle 100 is not changing the lane.

  Note that the value of the offset distance threshold Dth is preferably set according to the value of the lane width W of the traveling lane. Specifically, the image processing ECU 11 detects the lane width W based on the front image, and transmits data indicating the lane width W to the lane keeping assist ECU 50. When the lane keeping assist ECU 50 starts the process of step A4 and step C21, first, the lane width W received from the image processing ECU 11 is calculated by multiplying the lane width W by a predetermined coefficient such as 1/2 as the offset distance threshold Dth. Then, it is preferable to execute the above-described determination process thereafter. By setting the offset distance threshold Dth in this way, the lane keeping assist ECU 50 can determine that the vehicle 100 is changing lanes when the vehicle 100 enters half of the vehicle width into the adjacent lane. .

  Further, the lane keeping assist ECU 50 may determine whether or not the vehicle 100 is changing the lane according to not only the operation state of the direction indicator 40 but also the operation state of the hazard lamp device of the vehicle 100. Specifically, the lane keeping assist ECU 50 is electrically connected to the hazard lamp device of the vehicle 100. The hazard lamp device transmits a hazard operation signal to the lane keeping assist ECU 50 while blinking according to an input operation from the driver. Then, the lane keeping assist ECU 50 determines whether or not a hazard operation signal has been received in step A4 and step C21 described above. The lane keeping assist ECU 50 determines that the vehicle 100 is changing lanes when the hazard operation signal is received. On the other hand, the lane keeping assist ECU 50 determines that the vehicle 100 is not changing the lane when the hazard operation signal is not received. For example, in an emergency, the driver of the vehicle 100 may turn on the hazard lamp and move the vehicle 100 to the shoulder. In such a case, it is preferable to suppress the generation of auxiliary torque that returns the vehicle to the center of the lane. Therefore, according to the processing of the lane keeping assist ECU 50 as described above, the driver can perform the steering operation of the vehicle 100 with a smaller load than in the prior art even when operating the hazard lamp.

  The steering assist device according to the present invention is useful as a steering assist device that can appropriately reduce the steering load of the driver.

DESCRIPTION OF SYMBOLS 1 Steering assistance apparatus 10 Front monitoring camera 11 Image processing ECU
20 vehicle speed sensor 30 yaw rate sensor 40 direction indicator 50 lane keeping assist ECU
60 Steering device 61 Steering sensor 62 Steering control ECU
63 Steering actuator 100 Vehicle

Claims (3)

A lane keeping assist device that assists a driver in operating a vehicle so that the vehicle keeps traveling along the lane,
Auxiliary torque generating means for generating auxiliary torque for assisting the steering force of the driver in the vehicle;
Detecting means for detecting a lane change of the vehicle based on presence or absence of operation of a direction indicator provided in the vehicle;
The assist torque generating means, the auxiliary torque required to turning the vehicle which has been allowed to occur before the direction indicator is operated in accordance with the curvature of the traffic lane, the direction indicator is operated A lane keeping assist device characterized in that the lane keeping assist device is generated continuously after a while. The auxiliary torque generating means controls the value of auxiliary torque necessary for turning the vehicle that continues to be generated according to the curvature of the traveling lane based on the operation direction of the direction indicator. The lane keeping assist device according to claim 1 . The assist torque generating means, the auxiliary torque necessary for turning according to the vehicle to the curvature of the traffic lane, the direction indicator of the operation is determined to lane change of the vehicle is released is completed The lane keeping assist device according to claim 1, wherein the lane keeping assist device is generated continuously until the lane maintenance.

Images