Lane changing auxiliary device

Abstract

The present disclosure relates to a lane change assistance device that determines whether or not a vehicle can change a lane ahead of another vehicle traveling prior to the vehicle on a lane change target lane through a first determination or a second determination. The first determination is whether or not the sum of the distance traveled by the own vehicle to a predetermined preceding distance in front of the other vehicle for lane change and the distance traveled by the own vehicle within a predetermined margin time is less than or equal to the distance from the current position of the own vehicle to the bifurcation point. The second determination is a determination whether the sum of the time required for the own vehicle to move to a predetermined preceding distance ahead of the other vehicle in order to change the lane and the predetermined margin time is equal to or less than the time until the own vehicle reaches the bifurcation point.

Description

Technical Field

[0001] The present invention relates to a lane change assist device for vehicles such as automobiles. Background Art

[0002] As one of the lane change assist devices, there is known a lane change assist device that determines whether the own vehicle can change lanes when the own vehicle needs to change lanes and another vehicle is traveling in a lane change target lane.

[0003] For example, Japanese Patent Application Laid-Open No. 2021-76983 describes a lane change assist device, which, when the vehicle wants to change lanes before reaching the fork point (intersection) of the lane, considers the distance from the vehicle to the fork point to determine whether the lane change is possible, so as to avoid changing lanes behind other vehicles that are slower than the vehicle even though the distance to the fork point is long enough. According to this lane change assist device, it is possible to prevent the situation where the vehicle changes lanes behind other vehicles that are slower than the vehicle even though the distance to the fork point is long enough. Summary of the invention

[0004] However, in a conventional lane change assist device such as the device described in Japanese Patent Application Laid-Open No. 2021-76983, it is sometimes determined that the lane change is not possible even if the lane change is possible, depending on the positional relationship between the own vehicle and other vehicles traveling in the lane change target lane.

[0005] The present invention determines whether a lane change is possible based on the distance to a branch point and the positional relationship between the own vehicle and other vehicles. An improved lane change assist device is provided, which can reduce the possibility of determining that a lane change is not possible even if the lane change is possible.

[0006] According to the present invention, a lane change assist device (100) is provided, which includes: a target object information acquisition device (18) that acquires information about target objects around the own vehicle (102); a vehicle speed information acquisition device (vehicle state sensor 70) that acquires information about the vehicle speed of the own vehicle; and a control unit (driving assistance ECU 10) that is configured to estimate, based on the information acquired by the target object information acquisition device, a vehicle distance (Lip) between the own vehicle and another vehicle (112) traveling ahead of the own vehicle (in front of the own vehicle) in the lane change target lane (110) and a relative vehicle speed (Vr) of the own vehicle relative to the other vehicle.

[0007] The control unit (driving assistance ECU 10) is configured to obtain information about the distance (Lbp) from the current position (current location) of the own vehicle to the lane bifurcation point, and to perform one of a first determination and a second determination based on the vehicle speed (Vo) of the own vehicle, the inter-vehicle distance (Lip), the relative vehicle speed (Vr), and the distance from the current position of the own vehicle to the lane bifurcation point to determine whether the own vehicle can change lanes in front of the other vehicle (S60), wherein the first determination is a predetermined leading distance (Lbp) that the own vehicle moves to in front of the other vehicle in order to change lanes. if) and the distance (Ta*Vo) traveled by the own vehicle within the predetermined margin time (Ta) are less than the distance (Lbp) from the current position of the own vehicle to the branch point; the second judgment is whether the sum of the time ((Lip+Lif) / Vr) required for the own vehicle to move to the predetermined leading distance (Lif) in front of the other vehicle in order to change lanes and the predetermined margin time (Ta) is less than the time (Lbp / Vo) until the own vehicle reaches the branch point.

[0008] According to the above configuration, one of the first determination and the second determination is performed. The first determination is to determine whether the sum of the distance traveled by the own vehicle to the predetermined leading distance in front of the other vehicle in order to change lanes and the distance traveled by the own vehicle within the predetermined margin time Ta is less than the distance from the current position of the own vehicle to the branch point. In addition, the second determination is to determine whether the sum of the time required for the own vehicle to move to the predetermined leading distance in front of the other vehicle in order to change lanes and the predetermined margin time is less than the time until the own vehicle reaches the branch point.

[0009] Therefore, by determining one of the first determination and the second determination, it is possible to determine whether the own vehicle can change lanes in front of other vehicles that are traveling ahead of the own vehicle in the lane change target lane. This can reduce the possibility of being determined as unable to change lanes even if it is possible to change lanes in front of other vehicles.

[0010] In one technical solution of the present invention, the control unit (driving assistance ECU 10) is configured to determine the deceleration (i.e., the permissible deceleration (Gxp)) that can be allowed for the predetermined subsequent distance (Lib) that the own vehicle moves to the rear of the other vehicle for lane change when one of the first determination and the second determination is a negative determination, and determine whether the own vehicle can change lanes behind the other vehicle by performing one of the third determination and the fourth determination (S80), wherein the third determination is the distance (Vr) that the own vehicle approaches the other vehicle before the relative vehicle speed becomes zero due to the own vehicle decelerating at the permissible deceleration. 2 / (2Gxp)) and the predetermined subsequent distance (Lib) are below the inter-vehicle distance (Lip), and the fourth judgment is based on whether the sum of half the time (Vr / (2Gxp)) for the own vehicle to decelerate at the allowable deceleration and the relative vehicle speed to become 0 and the time required for the own vehicle to travel the predetermined subsequent distance (Lib / Vr) is below the time (Lip / Vr) for the own vehicle to catch up with the other vehicle.

[0011] In another technical solution of the present invention, the control unit (driving assistance ECU 10) is configured to perform a fifth judgment when one of the third judgment and the fourth judgment is a negative judgment. The fifth judgment is a judgment (S100) on whether the own vehicle can change lanes and move to the predetermined leading distance (Lif) in front of the other vehicle before the own vehicle reaches the fork point by accelerating the own vehicle.

[0012] Furthermore, in another aspect of the present invention, the control unit (driving assistance ECU 10 ) is configured to request the driver to determine whether the own vehicle can change lanes and move ahead of the other vehicle ( S120 ) when the fifth determination ( S100 ) is a negative determination.

[0013] Furthermore, in another aspect of the present invention, the control unit (driving assistance ECU 10 ) is configured to determine the allowable deceleration ( S80 ) based on the vehicle speed (Vo) of the own vehicle.

[0014] In the above description, other objects, other features and attendant advantages of the present invention will be easily understood from the following description of the embodiments of the present invention described with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Hereinafter, features, advantages, and technical and industrial significance of exemplary embodiments of the present invention will be described with reference to the accompanying drawings, in which like reference numerals represent like elements, and wherein:

[0016] Figure 1 is a schematic diagram showing the configuration of a lane change assist device according to an embodiment;

[0017] Figure 2 is a flowchart corresponding to a lane change mode (method) determination procedure in an embodiment;

[0018] Figure 3 is a flow chart corresponding to the lane change control program in the implementation mode;

[0019] Figure 4 is a diagram showing a map for calculating the permissible deceleration Gxp based on the vehicle speed Vo of the own vehicle;

[0020] Figure 5 A diagram showing the method of determining whether or not a lane change can be made ahead of another vehicle traveling ahead of the own vehicle in the lane change target lane without accelerating or decelerating before reaching a lane divergence point;

[0021] Figure 6 The diagram shows a method for determining whether or not it is possible to change lanes behind another vehicle traveling ahead of the own vehicle in the lane change target lane at a deceleration equal to or less than the permissible deceleration. DETAILED DESCRIPTION

[0022] Hereinafter, a lane change assist device according to an embodiment of the present invention will be described in detail with reference to the accompanying drawings.

[0023] like Figure 1 As shown, the lane change assist device 100 according to the embodiment of the present invention is applicable to a vehicle 102, and includes a driving assist ECU (Electronic Control Unit) 10. The vehicle 102 is a vehicle capable of automatic driving, and includes a drive ECU 20, a brake ECU 30, an electric power steering ECU 40, and a meter ECU 50. In addition, in the following description, the electric power steering is referred to as EPS (Electric Power Steering).

[0024] The microcomputer of each ECU includes a CPU, ROM, RAM, a readable and writable non-volatile memory (N / M), and an interface (I / F). The CPU implements various functions by executing instructions (programs, routines) stored in the ROM. Furthermore, these ECUs are connected to each other via CAN (Controller Area Network) 104 in a manner that allows data exchange (communication). Therefore, the detection values ​​of sensors (including switches) connected to a specific ECU are also sent to other ECUs.

[0025] The driving assistance ECU 10 is a central control device that performs driving assistance control such as lane change assistance control and lane keeping control. In the embodiment, as described in detail later, the driving assistance ECU 10 cooperates with other ECUs to perform lane change assistance control of the vehicle 102 .

[0026] The driving support ECU 10 is connected to a camera sensor 12, a radar sensor 14, and a setting operator 16. The camera sensor 12 and the radar sensor 14 include a plurality of camera devices and a plurality of radar devices, respectively. The camera sensor 12 and the radar sensor 14 function as a target object information acquisition device 18 that acquires information about targets around the vehicle 102.

[0027] Although not shown in the figure, each camera device of the camera sensor 12 includes a camera unit for photographing the surroundings of the vehicle 102, and a recognition unit for analyzing image data obtained by the camera unit to recognize targets such as white lines on the road and other vehicles. The recognition unit supplies information related to the recognized target to the driving assistance ECU 10 at predetermined intervals.

[0028] Each radar device of the radar sensor 14 is equipped with a radar transceiver and a signal processing unit (not shown). The radar transceiver transmits radio waves in the millimeter wave band (hereinafter referred to as "millimeter waves") and receives millimeter waves (i.e., reflected waves) reflected by three-dimensional objects (e.g., other vehicles, bicycles, etc.) within the transmission range. The signal processing unit supplies information indicating the distance between the own vehicle and the three-dimensional object, the relative speed between the own vehicle and the three-dimensional object, the relative position (direction) of the three-dimensional object relative to the own vehicle, etc. to the driving assistance ECU 10 at predetermined intervals based on the phase difference between the transmitted millimeter wave and the received reflected wave, the attenuation level of the reflected wave, and the time from transmitting the millimeter wave to receiving the reflected wave. In addition, LiDAR (Light Detection And Ranging) can also be used as a substitute for the radar sensor 14 or as a supplement to the radar sensor 14.

[0029] Set the operator 16 as Figure 1 The steering wheel shown in the figure is arranged in a position where it can be operated by the driver and is operated by the driver. Figure 1 Although not shown, the setting operator 16 includes a lane change assist switch. As described in detail later, when the lane change assist switch is turned on and a predetermined condition described later is satisfied, the driving assistance ECU 10 starts lane change assist control.

[0030] The drive ECU 20 is connected to a drive device 22 that accelerates the vehicle 102 by applying a driving force to a drive wheel 24. The drive ECU 20 normally controls the drive device 22 so that the driving force generated by the drive device 22 varies according to a driving operation performed by the driver, and if a command signal is received from the driving assistance ECU 10, the drive device 22 is controlled based on the command signal.

[0031] The brake ECU 30 is connected to a brake device 32 that decelerates the vehicle 102 by applying a braking force to the wheels 34. The brake ECU 30 normally controls the brake device 32 so that the braking force generated by the brake device 32 changes according to the brake operation performed by the driver. If the brake ECU 30 receives a command signal from the driving assistance ECU 10, it controls the brake device 32 based on the command signal to perform automatic braking. In addition, when the braking force is applied to the wheels, Figure 1The brake lights (not shown) come on.

[0032] The EPS-ECU 40 is connected to an EPS device 42. The EPS-ECU 40 controls the EPS device 42 in a manner known in the art based on the steering torque Ts and the vehicle speed Vo detected by the driving operation sensor 60 and the vehicle state sensor 70 described later. The EPS-ECU 40 controls the steering assist torque by controlling the EPS device 42, thereby reducing the steering burden on the driver. In addition, the EPS-ECU 40 can steer the steering wheel 44 as needed by controlling the EPS device 42. Thus, the EPS-ECU 40 and the EPS device 42 function as an automatic steering device that automatically steers the steering wheel as needed.

[0033] As can be seen from the above description, the drive ECU 20 , the drive device 22 , the brake ECU 30 , the brake device 32 , the EPS-ECU 40 , and the EPS device 42 function as the travel control device 90 that controls the travel of the vehicle 102 such as braking, driving, and turning.

[0034] A touch panel type display 52 for displaying the status of control performed by the driving assistance ECU 10 is connected to the meter ECU 50. The display 52 may be, for example, a multifunctional information display for displaying meters and various information, or may be a display of a navigation device 80 described later. As described later, the display 52 displays the status of the lane change assist control when receiving a signal from the driving assistance ECU 10.

[0035] The driving operation sensor 60 and the vehicle state sensor 70 are connected to the CAN 104. The information detected by the driving operation sensor 60 and the vehicle state sensor 70 (referred to as sensor information) is sent to the CAN 104. The sensor information sent to the CAN 104 can be used appropriately in each ECU. In addition, the sensor information may also be information of a sensor connected to a specific ECU, and sent from the specific ECU to the CAN 104.

[0036] The driving operation sensor 60 includes a driving operation amount sensor for detecting the operation amount of the accelerator pedal, a braking operation amount sensor for detecting the master cylinder pressure or the pedal force on the brake pedal, etc. In addition, the driving operation sensor 60 includes a steering angle sensor for detecting the steering angle θ, a steering torque sensor for detecting the steering torque Ts, etc. Furthermore, the driving operation sensor 60 also includes a turn lever that the driver operates when he wants to change lanes.

[0037] The vehicle state sensor 70 includes a vehicle speed sensor for detecting the vehicle speed Vo of the vehicle 102. In addition, the vehicle state sensor 70 includes a front and rear acceleration sensor for detecting the acceleration of the vehicle in the front and rear directions. In addition, the vehicle state sensor 70 includes a lateral acceleration sensor for detecting the acceleration of the vehicle in the lateral direction. In addition, the vehicle state sensor 70 includes a yaw rate sensor for detecting the yaw rate of the vehicle, etc.

[0038] Furthermore, the navigation device 80 is also connected to the CAN 104. The navigation device 80 includes a GPS receiver for detecting the position of the vehicle 102, a storage device for storing map information and road information, and a communication device for obtaining the latest information of the map information and road information from the outside. The navigation device 80 functions as a device for obtaining information of the current position of the vehicle 102, and outputs a signal indicating the current position of the vehicle on the map to the driving assistance ECU 10. Furthermore, when a destination is input to the navigation device 80, the target route from the current position of the vehicle 102 to the destination is determined, and the vehicle is guided to travel along the target route. In particular, when there is a fork in front of the vehicle and the vehicle needs to change lanes in front of the fork in order to travel along the target route, the navigation device 80 displays the need to change lanes on the display 52. ​​While the navigation device 80 displays the need to change lanes on the display 52 to notify the driver, it notifies the driving assistance ECU 10.

[0039] In the embodiment, the ROM of the driving assistance ECU 10 stores Figure 2 In addition, in the embodiment, the ROM of the driving assistance ECU 10 stores the lane change mode determination program corresponding to the flowchart shown in FIG. Figure 3 The flowchart shown corresponds to the lane change control program. Thus, in the embodiment, the lane change assist control is performed through the control of the lane change mode determination and the lane change control.

[0040] Lane change mode determination

[0041] Next, refer to Figure 2 The flowchart shown in FIG. 1 illustrates the lane change mode determination in the embodiment. In the case where the target route to the destination is set by the navigation device 80, based on Figure 2 The lane change mode determination in the flowchart shown is repeatedly executed by the CPU of the driving assistance ECU 10 at predetermined time intervals.

[0042] First, in S10, the CPU determines whether it is necessary to change lanes before the fork point based on the relationship between the lane that the vehicle should travel after passing the fork point located on the way to the target path to the destination and closest to the current position of the vehicle 102 and the current lane. When the CPU makes a negative determination, S10 is repeatedly executed, and when a positive determination is made, the control proceeds to S20.

[0043] In S20 , the CPU outputs a command signal to the meter ECU 50 , causing the display 52 to indicate that a lane change is necessary.

[0044] In S30, the CPU queries the navigation device 80, such as Figure 5 As shown, the distance Lbp [m] from the current position of the vehicle 102 to the branch point Pbp where lane change is required is calculated. Then, the CPU determines whether the distance Lbp is greater than the reference distance Lbpc (positive constant). When the CPU makes a positive determination, the control proceeds to S50, and when the CPU makes a negative determination, the control proceeds to S40.

[0045] In S40, Figure 5 As shown, the CPU estimates the inter-vehicle distance Lip [m] between the own vehicle 102 and the other vehicle 112 that is traveling ahead of the own vehicle in the lane change target lane 110. Furthermore, the CPU determines whether the inter-vehicle distance Lip is greater than the reference inter-vehicle distance Lipc (a positive constant). When the CPU makes a negative determination, the control proceeds to S60, and when the CPU makes an affirmative determination, the control proceeds to S50.

[0046] In S50 , the CPU stores in the RAM that the lane change can be made behind another vehicle 112 traveling ahead of the own vehicle in the lane change target lane 110 without acceleration or deceleration, notifies the lane change control routine, and displays the information on the display 52 .

[0047] In S60, the CPU determines whether it is possible to change lanes in front of another vehicle 112 traveling ahead of the own vehicle in the lane change target lane 110 without accelerating or decelerating before reaching the lane bifurcation point by performing one of the first determination and the second determination described below. When the CPU makes a negative determination, the control proceeds to S80, and when the CPU makes an affirmative determination, the control proceeds to S70.

[0048] The first determination is to determine whether the sum of the distance traveled by the own vehicle to the predetermined leading distance in front of the other vehicle in order to change lanes and the distance traveled by the own vehicle within the predetermined margin time is less than the distance from the current position of the own vehicle to the branch point. In addition, the second determination is to determine whether the sum of the time required for the own vehicle to move to the predetermined leading distance in front of the other vehicle in order to change lanes and the predetermined margin time is less than the time until the own vehicle reaches the branch point.

[0049] like Figure 5As shown, the inter-vehicle distance between the own vehicle 102 and the other vehicle 112 traveling ahead of the own vehicle 102 on the lane change target lane 110 is set to Lip. The inter-vehicle distance (predetermined preceding distance) that the own vehicle 102 wants to ensure with other vehicles 112 when completing the lane change is set to Lif. The predetermined margin time that the own vehicle 102 wants to ensure from the completion of the lane change to the arrival at the branch point Pbp is set to Ta, and the relative speed of the own vehicle 102 to the other vehicle 112, that is, the difference Vo-Vp between the vehicle speed Vo of the own vehicle and the vehicle speed Vp of the other vehicle is set to Vr. In addition, the value of the above-mentioned inter-vehicle distance Lip and the like is estimated based on the detection result of the target object information acquisition device 18.

[0050] The first determination may be, for example, a determination of whether the following equation (1) holds true, and the second determination may be, for example, a determination of whether the following equation (2) holds true.

[0051] {(Lip+Lif) / Vr+Ta}*Vo≤Lbp…(1)

[0052] (Lip+Lif) / Vr+Ta≤Lbp / Vo…(2)

[0053] In S70 , the CPU stores in the RAM that the lane change can be made ahead of the other vehicle 112 traveling ahead of the own vehicle in the lane change target lane 110 without acceleration or deceleration, notifies the lane change control routine, and displays the information on the display 52 .

[0054] In S80, the CPU determines the deceleration that can be allowed when the own vehicle 102 moves to a predetermined subsequent distance behind the other vehicle 112 for lane change, that is, the allowable deceleration Gxp. In this case, in order to determine the allowable deceleration Gxp according to the speed Vo of the own vehicle, the speed Vo of the own vehicle is based on the allowable deceleration Gxp. Figure 4 The mapping shown in FIG. 1 is calculated, but the permissible deceleration Gxp may also be a positive constant. Furthermore, the CPU determines whether it is possible to change lanes behind another vehicle 112 traveling ahead of the vehicle in the lane change target lane 110 by decelerating at the permissible deceleration by performing one of the third determination and the fourth determination described below. When the CPU makes a negative determination, the control proceeds to S100, and when the CPU makes an affirmative determination, the control proceeds to S90.

[0055] The third determination is to determine whether the sum of the distance the own vehicle approaches the other vehicle before the relative speed becomes 0 due to the self-vehicle decelerating at the allowable deceleration and the predetermined following distance is less than the inter-vehicle distance between the own vehicle and the other vehicle. In addition, the fourth determination is to determine whether the sum of the time until the relative speed becomes 0 due to the self-vehicle decelerating at the allowable deceleration and the time required for the own vehicle to travel the predetermined following distance is less than the time until the own vehicle catches up with the other vehicle.

[0056] like Figure 6 As shown, the predetermined follow-up distance, that is, the inter-vehicle distance (predetermined follow-up distance) that the own vehicle 102 wants to ensure with the other vehicle 112 when completing the lane change is set as Lib. The time required before the own vehicle decelerates and the relative speed Vr becomes 0 is Vr / Gxp, and the average relative speed until the own vehicle decelerates and the relative speed Vr becomes 0 is Vr / 2. Therefore, the distance Lap that the own vehicle approaches to the other vehicle before the own vehicle decelerates and the relative speed Vr becomes 0 is expressed by the following formula (A).

[0057] Lap=(Vr / Gxp)*(Vr / 2)=Vr 2 / (2Gxp)…(A)

[0058] Therefore, the third determination may be, for example, a determination of whether the following equation (3) holds true, and the fourth determination may be, for example, a determination of whether the following equation (4) holds true.

[0059] Vr 2 / (2Gxp)+Lib≤Lip…(3)

[0060] Vr / (2Gxp)+Lib / Vr≤Lip / Vr…(4)

[0061] In S90, the CPU stores in the RAM that the lane change is possible by decelerating at the permissible deceleration Gxp to the rear of the other vehicle 112 traveling ahead of the own vehicle in the lane change target lane 110. By storing the lane change possibility in the RAM, the lane change control routine is informed and displayed on the display 52.

[0062] In S100, the CPU makes the following fifth determination: whether the own vehicle 102 can change lanes and move to a predetermined leading distance in front of the other vehicle before the own vehicle reaches the branch point by accelerating the own vehicle 102. When the CPU makes a negative determination, the control proceeds to S120, and when the CPU makes an affirmative determination, the control proceeds to S110.

[0063] In S110 , the CPU stores in the RAM that the vehicle can change lanes ahead of another vehicle 112 traveling ahead of the vehicle in the target lane 110 by accelerating, notifies the lane change control routine, and displays the information on the display 52 .

[0064] In S120 , the CPU displays on the display 52 a request for the driver to determine whether or not the driver can change lanes to the front or rear of another vehicle 112 traveling ahead of the own vehicle in the lane change target lane 110 .

[0065] Lane Change Control

[0066] Next, refer to Figure 3 The flowchart shown in FIG. 1 is used to explain the lane change control in the embodiment. When the lane change assist switch is turned on, the RAM stores the information indicating that the lane change is possible. Figure 3 The lane change control in the flowchart shown is repeatedly executed by the CPU of the driving assistance ECU 10 at predetermined time intervals.

[0067] First, in S210, the CPU determines whether the own vehicle 102 is changing lanes. When the CPU makes an affirmative determination, the control proceeds to S250, and when the CPU makes a negative determination, the control proceeds to S220. In addition, based on the detection result of the target object information acquisition device 18, when the own vehicle 102 is moving laterally relative to the lane and when it is determined that the first determination time (positive constant) has not passed after the lateral movement is completed, it can be determined that the vehicle is changing lanes.

[0068] In S220, the CPU determines whether there is a notification that the lane change is possible based on whether the determination that the lane change is possible is stored in the RAM. When the CPU makes a negative determination, the control returns to S210, and when the CPU makes an affirmative determination, the control proceeds to S230.

[0069] In S230, the CPU determines whether the driver intends to change lanes based on whether the steering rod is tilted to the side where lane change is possible. When the CPU makes a negative determination, the control returns to S210, and when the CPU makes a positive determination, the control proceeds to S240. Figure 1 Whether a button (not shown) is operated, the driver's posture, etc. are used to determine whether the driver intends to change lanes.

[0070] In S240, the CPU determines whether the lane change is possible based on whether there are other vehicles that are obstacles to the lane change, etc. The CPU advances the control to S280 when a negative determination is made, and advances the control to S290 when an affirmative determination is made.

[0071] In S250, the CPU determines whether the lane change is possible in the same manner as in S240. When the CPU makes an affirmative determination, the control proceeds to S270, and when the CPU makes a negative determination, the lane change is stopped in S260 and the control proceeds to S280.

[0072] In S270, the CPU determines whether the lane change has been completed. When the CPU makes a negative determination, the control proceeds to S300, and then proceeds to S250 via S210. When the CPU makes an affirmative determination, the control proceeds to S310. In addition, based on the detection result of the target object information acquisition device 18, when it is determined that a second determination time (positive constant) shorter than the first determination time has passed after the end of the lateral movement of the own vehicle 102, it can be determined that the lane change has been completed.

[0073] In S280, the CPU displays that the lane change is impossible on the display 52. ​​In S290, the CPU starts the lane change in a manner known in the art by outputting a lane change command signal to the EPS-ECU 40, etc., and displays on the display 52 that the lane change has started.

[0074] In S300, the CPU outputs a lane change command signal to the EPS-ECU 40, etc., continues to execute the lane change in a manner known in the art, and displays the lane change continuing on the display 52. ​​In S310, the CPU deletes the storage of the lane change capability from the RAM, and displays the lane change completion on the display 52.

[0075] As can be seen from the above description, according to the embodiment, when it is determined that a lane change is required (S10), it is determined that the distance Lbp from the current position of the own vehicle 102 to the branch point Pbp is less than the reference distance Lbpc (S30), and it is determined that the inter-vehicle distance Lip is less than the reference inter-vehicle distance Lipc, the determination of step S60 is first performed. In S60, one of the first determination and the second determination corresponding to the above-mentioned equations (1) and (2) is performed.

[0076] The first determination is whether the sum of the distance (Lip+Lif) / Vr*Vo that the own vehicle 102 travels to the predetermined leading distance Lif in front of the other vehicle 112 for lane change and the distance Ta*Vo that the own vehicle travels within the predetermined margin time Ta is less than the distance Lbp from the current position of the own vehicle to the branch point. In addition, the second determination is whether the sum of the time (Lip+Lif) / Vr required for the own vehicle to move to the predetermined leading distance in front of the other vehicle for lane change and the predetermined margin time Ta is less than the time Lbp / Vo until the own vehicle reaches the branch point.

[0077] Therefore, according to the embodiment, through the determination in S60, it can be determined whether the own vehicle 102 can change lanes in front of the other vehicle 112 that is traveling ahead of the own vehicle 102 in the lane change target lane 110. In addition, when an affirmative determination is made in S60, in S70, it is displayed on the display 52 that the own vehicle 102 can change lanes in front of the other vehicle 112 without accelerating or decelerating. As a result, the driver can recognize that the own vehicle can change lanes in front of the other vehicle without accelerating or decelerating, and the possibility of determining that the lane change is not possible even though the lane change in front of the other vehicle is possible can be reduced.

[0078] Furthermore, according to the embodiment, a positive determination is made in S220 and S230, and if the lane change is possible, a positive determination is made in S240, and in S290, the lane change is started in front of the other vehicle by automatic driving without acceleration or deceleration. Furthermore, the lane change is continued until the lane change is completed and a positive determination is made in S270. In this way, the own vehicle 102 can automatically change lanes in front of the other vehicle 112.

[0079] In addition, according to the embodiment, when a negative determination is made in S60, a determination in step S80 is performed. In S80, the deceleration that can be allowed when the own vehicle 102 moves to a predetermined subsequent distance Lib behind the other vehicle 112 for lane change, that is, the allowable deceleration Gxp, is calculated, and one of the third determination and the fourth determination corresponding to the above-mentioned equations (3) and (4), respectively, is performed.

[0080] The third determination is the distance Vr by which the own vehicle approaches the other vehicle before the relative speed Vr becomes zero due to the own vehicle 102 decelerating at the permissible deceleration Gxp. 2 / (2Gxp) and the scheduled follow-up distance Lib is less than the inter-vehicle distance Lip between the own vehicle and the other vehicle. In addition, the fourth judgment is whether the sum of half the time Vr / (2Gxp) until the relative speed Vr becomes 0 by decelerating the own vehicle at the allowable deceleration Gxp and the time Lib / Vr required for the own vehicle to travel the scheduled follow-up distance Lib is less than the time Lip / Vr until the own vehicle catches up with the other vehicle.

[0081] Therefore, according to the embodiment, through the determination in S80, it can be determined whether the own vehicle 102 can decelerate to change lanes behind the other vehicle 112 that is traveling ahead of the own vehicle 102 in the lane change target lane 110. In addition, when an affirmative determination is made in S80, in S90, the display 52 displays that the own vehicle 102 can decelerate to change lanes behind the other vehicle 112. As a result, the driver can recognize that the own vehicle can decelerate to change lanes behind the other vehicle, and the possibility of determining that the lane change is impossible even though the lane change is possible behind the other vehicle can be reduced.

[0082] Furthermore, according to the embodiment, a positive determination is made in S220 and S230, and if lane change is possible, a positive determination is made in S240, and in S290, the lane change starts behind the other vehicle by performing automatic deceleration. Furthermore, the lane change continues until the lane change is completed and a positive determination is made in S270. Thus, the own vehicle can automatically decelerate and change lanes behind the other vehicle.

[0083] In addition, according to the embodiment, when a negative determination is made in step S80, a determination is made in step S100. In step S100, a fifth determination is made as to whether the own vehicle 102 can change lanes and move to a predetermined leading distance ahead of the other vehicle before the own vehicle reaches the branch point by accelerating the own vehicle 102.

[0084] Therefore, according to the embodiment, through the determination in S100, it can be determined whether the own vehicle 102 can be accelerated to change lanes in front of the other vehicle 112 that is traveling ahead of the own vehicle 102 in the lane change target lane 110. In addition, when an affirmative determination is made in S100, in S110, the fact that the own vehicle 102 can be accelerated to change lanes in front of the other vehicle 112 is displayed on the display 52. ​​As a result, the driver can recognize that the own vehicle can be accelerated to change lanes in front of the other vehicle, and the possibility that the lane change can be made in front of the other vehicle by simply accelerating the own vehicle can be reduced.

[0085] Furthermore, according to the embodiment, positive determinations are made in S220 and S230, and if lane change is possible, positive determination is made in S240, so that in S290, lane change starts to be made in front of the other vehicle by performing automatic driving with acceleration. Furthermore, lane change continues until the lane change is completed and a positive determination is made in S270. Thus, the own vehicle can automatically accelerate and change lanes in front of the other vehicle.

[0086] Furthermore, according to the embodiment, when a negative determination is made in S100, step S120 is executed. In S120, the driver is requested to make a judgment on whether to change lanes in front of or behind the other vehicle 112. This allows the driver to recognize that it is necessary to make a judgment on whether to change lanes in front of or behind the other vehicle 112.

[0087] Furthermore, since a negative determination is made in S220, the lane change by the automatic driving is not performed. Thus, it is possible to avoid a forced lane change by the automatic driving.

[0088] Furthermore, according to the embodiment, the deceleration that can be allowed when the own vehicle 102 moves to a predetermined subsequent distance behind the other vehicle 112 for lane change is the allowable deceleration Gxp based on the vehicle speed Vo of the own vehicle according to Figure 4 This makes it possible to appropriately determine whether or not the vehicle can decelerate and change lanes behind the other vehicle 112 before reaching the lane branch point, compared to a case where the permissible deceleration Gxp is constant regardless of the vehicle speed Vo of the own vehicle.

[0089] As mentioned above, the present invention has been described in detail with respect to specific embodiments, but the present invention is not limited to the above-mentioned embodiments, and it is obvious to those skilled in the art that various other embodiments can be implemented within the scope of the present invention.

[0090] For example, in the above-mentioned embodiment, one of the first determination and the second determination is performed in S60. When one of the first determination and the second determination is a negative determination, one of the third determination and the fourth determination is performed in S80. When one of the third determination and the fourth determination is a negative determination, the fifth determination is performed in S100. However, it is also possible to first perform one of the third determination and the fourth determination, and when the one is a negative determination, perform one of the first determination and the second determination, and when the one is a negative determination, perform the fifth determination.

[0091] In addition, in the above-mentioned embodiment, one of the first determination and the second determination as determinations of whether the above-mentioned formula (1) and formula (2) are established is performed in S60. The above-mentioned formula (1) and formula (2) may be replaced by, for example, the following formula (5) and formula (6), respectively. In the following formula (5), La is Ta*Vo, and in the following formula (6) and formula (7) and formula (8) described later, Tr is Lip / Vr.

[0092] (Lip+Lif) / Vr*Vo+La≤Lbp…(5)

[0093] (Lif / Vr+Tr+Ta)*Vo≤Lbp…(6)

[0094] In the above embodiment, one of the third determination and the fourth determination is performed in S80 as a determination of whether the above equations (3) and (4) are satisfied. The above equations (3) and (4) may be replaced by the following equations (7) and (8), respectively.

[0095] Vr 2 / (2Gxp)+Lib≤Tr*Vr…(7)

[0096] Vr / (2Gxp)+Lib / Vr≤Tr…(8)

[0097] In addition, in the above-mentioned embodiment, the inter-vehicle distance is the distance along the lane between the front ends of two vehicles. However, the inter-vehicle distance Lpr in the determination of S40 may also be the distance Lipfe between the front end of the own vehicle 102 estimated based on the information from the target object information acquisition device 18 and the rear end of the other vehicle 112 traveling ahead of the own vehicle 102 in the lane change target lane 110. In this case, the length of the other vehicle 112 estimated based on the information from the target object information acquisition device 18 is set to Lpv, and the reference inter-vehicle distance may be Lprc-Lpv.

[0098] In addition, the vehicle distance Lip in the above formula (1) can also be replaced by the distance Lipfe, and the predetermined leading distance Lif in the above formula (1) can also be replaced by the distance between the front end of the other vehicle 112 and the rear end of the own vehicle + the front and rear length of the own vehicle.

[0099] Similarly, the predetermined follow-up distance Lib in the above formula (3) can also be replaced by the distance Lipfe between the front end of the own vehicle 102 and the rear end of the other vehicle 112, and the sum of the length Lpv of the other vehicle 112 Lipfe+Lpv.

[0100] Furthermore, in the above-mentioned embodiment, when the Figure 2 The lane change mode determination in the flowchart shown in FIG. 1 is based on the Figure 3 The lane change control based on the flowchart shown in FIG. 1 is performed by automatic driving. However, the lane change based on the flowchart shown in FIG. 1 may be omitted. Figure 3 The flowchart shown is of lane change control.

Claims

1. A lane change assist device, comprising: A target object information acquisition device that acquires information about target objects around the own vehicle; A vehicle speed information acquisition device that acquires information on the speed of the own vehicle; as well as a control unit configured to estimate, based on the information acquired by the target object information acquisition device, a distance between the own vehicle and another vehicle traveling ahead of the own vehicle in the lane change target lane and a relative speed of the own vehicle with respect to the other vehicle, The control unit is configured to obtain information on the distance from the current position of the own vehicle to the bifurcation point of the lane, and determine whether the own vehicle can change lanes in front of the other vehicle by performing one of a first judgment and a second judgment based on the speed of the own vehicle, the vehicle-to-vehicle distance, the relative vehicle speed, and the distance from the current position of the own vehicle to the bifurcation point of the lane, wherein the first judgment is to determine whether the sum of the distance traveled by the own vehicle to a predetermined leading distance in front of the other vehicle in order to change lanes and the distance traveled by the own vehicle within a predetermined margin time is less than the distance from the current position of the own vehicle to the bifurcation point, and the second judgment is to determine whether the sum of the time required for the own vehicle to move to a predetermined leading distance in front of the other vehicle in order to change lanes and the predetermined margin time is less than the time until the own vehicle reaches the bifurcation point.

2. The lane change assist device according to claim 1, The control unit is configured to determine, when one of the first judgment and the second judgment is a negative judgment, the deceleration that is allowable for the own vehicle to move to a predetermined subsequent distance behind the other vehicle in order to change lanes, that is, the allowable deceleration, and to determine whether the own vehicle can change lanes behind the other vehicle by performing one of the third judgment and the fourth judgment, the third judgment being a judgment on whether the sum of the distance the own vehicle approaches the other vehicle before the relative vehicle speed becomes 0 due to the own vehicle decelerating at the allowable deceleration and the predetermined subsequent distance is less than the inter-vehicle distance, and the fourth judgment being a judgment on whether the sum of half the time until the relative vehicle speed becomes 0 due to the own vehicle decelerating at the allowable deceleration and the time required for the own vehicle to travel the predetermined subsequent distance is less than the time until the own vehicle catches up with the other vehicle.

3. The lane change assist device according to claim 2, The control unit is configured to perform a fifth judgment when one of the third judgment and the fourth judgment is a negative judgment, and the fifth judgment is to determine whether the own vehicle can change lanes and move to the predetermined leading distance in front of the other vehicle before the own vehicle reaches the branch point by accelerating the own vehicle.

4. The lane change assist device according to claim 3, The control unit is configured to request the driver to determine whether the host vehicle can change lanes and move ahead of the other vehicle when the fifth determination is a negative determination.

5. The lane change assist device according to claim 2, The control unit is configured to determine the allowable deceleration based on a vehicle speed of the own vehicle.

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