Driving assistance device

Abstract

A driving assistance device is provided with: a vehicle-mounted sensor including a sensor for acquiring the position and orientation of a host vehicle with respect to a lane on which the host vehicle is traveling, and a sensor for acquiring the vehicle speed of the host vehicle; and a processor configured so as to be able to execute lane maintenance processing for controlling the host vehicle so that the host vehicle travels along the lane. The processor restricts execution of the lane maintenance processing under a trigger condition that a direction indicator lamp of the host vehicle starts to operate under a condition that the host vehicle is traveling in a first lane. When it is determined that a lane change to a second lane adjacent to the first lane has been completed, and a predetermined release condition for controlling the host vehicle so as to cause the host vehicle to travel along the second lane has been satisfied, the lane change to the second lane is completed. The operation of the direction indicator light is stopped and the restriction of the execution of the lane maintenance processing is released.

Description

[0001] This application is a divisional application of Chinese patent application filed on February 17, 2025, with application number 202510171066.5 and invention title: "Driving Assist Device". Technical Field

[0002] The present invention relates to a driving assistance device that controls the steering mechanism of a vehicle in a manner that enables the vehicle to travel along a lane. Background Technology

[0003] A driving assistance device that controls the vehicle's steering mechanism in a manner that enables the vehicle to travel along a lane has been proposed (for example, see Japanese Patent Application Publication No. 2022-77931 below). The driving assistance device of Japanese Patent Application Publication No. 2022-77931 (hereinafter referred to as the "conventional device") analyzes an image (foreground image) obtained by capturing a view of the vehicle's foreground (view ahead) to control the vehicle's steering mechanism (lane-keeping function) in a manner that positions the vehicle near the center of the lane (driving lane) in the width direction. The conventional device disables the lane-keeping function while the driver is performing a driving operation (lane change) to move the vehicle from the first lane where the vehicle is currently located to a second lane adjacent to the first lane. Specifically, the conventional device disables the lane-keeping function when it detects that the vehicle's turn indicator light has started to operate (flashing). After disabling the lane-keeping function, the conventional device enables the lane-keeping function when a predetermined condition related to the positional relationship between the vehicle and the dividing line (the boundary line between the first and second lanes) is met based on the foreground image (when it is determined that the vehicle has crossed the dividing line). Summary of the Invention

[0004] Typically, when the steering system is automatically controlled via lane keeping assist, an upper limit is set for the vehicle's lateral acceleration (rudder angle) to suppress occupant discomfort. However, in situations where the vehicle's entry angle into the second lane is large during a lane change from the first lane to the second lane, even with automatic steering based on lane keeping assist, the vehicle may drift away from the end of the second lane (the end opposite to the first lane) while correcting its position and posture relative to the second lane to keep it within the second lane, due to the upper limit for lateral acceleration (rudder angle). Furthermore, while conventional devices activate the lane keeping function when predetermined conditions related to the lane markings and the vehicle's position are met, it is difficult for the driver to recognize the timing of its activation.

[0005] One of the objectives of this invention is to provide a driving assistance device that can disable the lane keeping function at the point when a driving operation for lane changing begins, and then re-enable the function at an appropriate time.

[0006] To solve the above-mentioned problems, the driving assistance device (1) of the present invention includes:

[0007] The vehicle-mounted sensors (20) include sensors (21, 22, 23) for obtaining the position and orientation of the vehicle relative to the lane in which the vehicle is traveling, and a sensor (24) for obtaining the vehicle speed; and

[0008] The processor (10) is configured to perform lane-keeping processing that controls the vehicle to travel along the lane.

[0009] When the vehicle is traveling in the first lane (L1), the processor restricts the execution of the lane keeping process by triggering the activation of the vehicle's turn indicator lights. Then, when it is determined that a lane change to the second lane (L2R, L2L) adjacent to the first lane has been completed, and a predetermined release condition is met to determine that the vehicle can be controlled in a manner that allows it to travel along the second lane, the processor stops the activation of the turn indicator lights and releases the restriction on the execution of the lane keeping process.

[0010] In conventional devices, where lane keeping operations are restarted at the point when a lane change from the first lane to the second lane is completed, the vehicle may sometimes slip out of the second lane shortly afterward, even though lane keeping operations have restarted. The processor of the driver assistance device of the present invention, upon determining that a lane change from the first lane to the second lane has been completed, restarts lane keeping operations when the condition (release condition) for controlling the vehicle in a manner sufficient to keep it traveling in the second lane is met. This prevents the vehicle from slipping out of the second lane shortly after lane keeping operations have restarted. In other words, according to the present invention, lane keeping operations are restarted at an appropriate timing after a lane change is completed. Furthermore, the turn indicator lights are automatically stopped (turned off) at the point when the release condition is met. This allows the driver to recognize the restart of lane keeping operations. That is, the driver can recognize that they are in a state where driving operations (steering) can be delegated to the driver assistance device to a certain extent.

[0011] In one technical solution of the present invention, a driving assistance device is involved.

[0012] When the processor detects that all wheels of the vehicle have entered the second lane based on information obtained from the on-board sensors, it determines that a lane change from the first lane to the second lane has been completed.

[0013] Therefore, it can prevent lane keeping assist (driving assistance) from starting when the vehicle is crossing the dividing line that separates the first and second lanes.

[0014] In another technical solution of the present invention, a driving assistance device is involved.

[0015] If the processor determines that the lane change has been completed, it assumes that the lane keeping process will start again from the current time point. The calculation is to predict the area that the vehicle will pass through until a predetermined condition related to the position and posture of the vehicle relative to the second lane is met through the execution of the lane keeping process, namely the predicted trajectory (TR). If the predicted trajectory is within the second lane, it is determined that the release condition is met.

[0016] Therefore, if the release condition is met, the vehicle will travel along the predicted trajectory, thereby preventing the vehicle from leaving the second lane.

[0017] In another technical solution of the present invention, a driving assistance device is involved.

[0018] After the processor detects that the turn indicator light has started operating while the vehicle is traveling in the first lane, if the cancellation condition for determining that it is difficult to perform the lane maintaining process in the second lane is met during the period before the lane change from the first lane to the second lane is determined to be completed, the processor stops the operation of the turn indicator light.

[0019] Therefore, if it can be predicted before the lane change is completed that it will be difficult to perform lane keeping procedures in the second lane, the driver is encouraged to interrupt the lane change.

[0020] In another technical solution of the present invention, a driving assistance device is involved.

[0021] The processor is configured to determine that the cancellation condition is met when the width of the second lane is below a threshold or when there is an obstacle in the second lane.

[0022] As a result, drivers can identify situations where the second lane is narrow or where there are obstacles in the second lane. Attached Figure Description

[0023] The features, advantages, and technical and industrial significance of exemplary embodiments of the present invention will be described below with reference to the accompanying drawings, wherein like reference numerals denote like elements, and wherein:

[0024] Figure 1 This is a block diagram of a driving assistance device according to one embodiment of the present invention.

[0025] Figure 2 This is a top view showing the vehicle's posture relative to the lane.

[0026] Figure 3 This is a top view showing an example where the predicted trajectory is within the second lane.

[0027] Figure 4 This is a top view showing an example of the predicted trajectory deviating from the second lane.

[0028] Figure 5 It is a flowchart of the program. Detailed Implementation

[0029] (roughly)

[0030] like Figure 1 As shown, one embodiment of the present invention relates to a driving assistance device 1 (lane keeping device) applied to a vehicle V0 (hereinafter referred to as "the vehicle") equipped with an autonomous driving function. The driving assistance device 1 has an LTA (Lane Tracing Assist) function that controls the vehicle to travel along the lane in a manner that enables the vehicle to travel along the lane in which it is traveling, when the autonomous driving function is disabled (the driver is performing driving operations).

[0031] (Specific composition)

[0032] The driver assistance device 1 includes an ECU 10, on-board sensors 20, a drive unit 30, a braking unit 40, a steering unit 50, a notification device 60, and a direction indicator 70.

[0033] ECU10 includes a microcomputer with CPU10a, ROM10b (flash ROM), RAM10c, timer 10d, etc. ECU10 is connected to other ECUs in the vehicle via CAN (Controller Area Network).

[0034] ECU10 is equipped with a microcomputer including CPU10a, ROM10b, RAM10c, timer 10d, etc. ECU10 is connected to other ECUs via CAN (Controller Area Network).

[0035] The vehicle sensors 20 include a camera 21, a millimeter-wave radar 22, a navigation system 23, a vehicle speed sensor 24, an acceleration sensor 25, and a driver assistance switch 26.

[0036] Camera 21 includes an image capturing device and an image analyzing device. The image capturing device, for example, incorporates a CCD. The image capturing device is positioned at the front of the vehicle. The image capturing device captures images of a predetermined area in front of the vehicle at a predetermined frame rate, obtaining a foreground (front view) image PIC. The image analyzing device analyzes the foreground image PIC obtained from the image capturing device to identify targets present in front of the vehicle. For example, the image analyzing device identifies preceding vehicles, lane markings (lines dividing lanes), etc. Based on the position (coordinates), extension direction, etc., of the lane markings in the foreground image PIC, the image analyzing device determines the position (position of the vehicle in the width direction of lane L1) and orientation (top view) of the vehicle in the lane L1 in which the vehicle is currently traveling. Figure 2 The angle φ between the vehicle's forward / backward direction and the extension direction of lane L1 (the tangent at the current location in a curved road) is calculated. The image analysis device provides the calculation result (position information and posture information) to the ECU10.

[0037] The millimeter-wave radar 22 includes a transceiver unit and a signal processing unit. The transceiver unit emits millimeter-wave radio waves (hereinafter referred to as "millimeter waves") to the area surrounding the vehicle (in front of the vehicle) and receives millimeter waves (reflected waves) reflected by three-dimensional objects located in that area. The signal processing unit obtains various information related to each reflection point of the millimeter waves based on physical quantities such as the time from the time the transceiver unit emits the millimeter waves to the time the reflected waves are received, the attenuation level of the reflected waves, and the difference between the frequency of the emitted millimeter waves and the frequency of the received reflected waves. For example, the signal processing unit calculates the position of each reflection point (relative position (direction and distance)) relative to the transceiver unit. In addition, the signal processing unit calculates the speed (relative speed) of each reflection point relative to the vehicle. And provides the calculation results (data representing the distribution of reflection points (position and relative speed of each reflection point relative to the vehicle)) to the ECU 10.

[0038] The navigation system 23 obtains location information (latitude and longitude) indicating the current location of the vehicle based on multiple GPS signals. Additionally, the navigation system 23 stores map information representing a map. Based on the location information and map information, the navigation system 23 obtains relevant information related to the road, including the lane the vehicle is currently traveling in (number of lanes, degree of curvature), and provides this information to the ECU 10.

[0039] The vehicle speed sensor 24 includes a rotation count measurement circuit and a vehicle speed calculation device. The rotation count measurement circuit includes a pulse generation circuit that outputs a pulse (electrical signal) each time the vehicle's wheels rotate a predetermined angle, and a counter circuit that counts the number of these pulses. The vehicle speed calculation device acquires the output value (pulse count) of the counter circuit at predetermined intervals (every unit of time) and resets the count value to "0". In this way, the vehicle speed calculation device acquires the number of wheel rotations N per unit of time. The vehicle speed calculation device obtains the vehicle speed sp0 (absolute value) by multiplying the rotation count N by a coefficient k. Furthermore, the vehicle speed calculation device provides the acquired vehicle speed sp0 to the ECU 10.

[0040] Acceleration sensor 25 includes a piezoelectric element. As the vehicle accelerates (or decelerates) in the longitudinal and / or lateral directions, the piezoelectric element deforms in the longitudinal and / or lateral directions, causing a change in its output voltage. Acceleration sensor 25 obtains the longitudinal and lateral accelerations of the vehicle based on the output voltage of the piezoelectric element. Furthermore, acceleration sensor 25 provides these accelerations to ECU 10.

[0041] The driving assistance switch 26 includes a push-button normally open switch (ACC switch and LTA switch) used to request the execution of driving assistance (ACC processing and LTA processing) described later from the driving assistance device 1. The ACC switch and LTA switch are configured to alternately switch between an on and off state each time they are pressed. In addition, the ACC switch and LTA switch can be forcibly switched to the off state according to instructions from other ECUs.

[0042] The drive unit 30 applies driving force to the drive wheels. The drive unit 30 includes an engine ECU, an internal combustion engine, a transmission, and a drive force transmission mechanism that transmits driving force to the wheels. The engine ECU obtains a target value of driving force from other ECUs (ECU 10). The engine ECU controls the throttle valve of the internal combustion engine in a manner that makes the driving force applied to the drive wheels consistent with the target value.

[0043] Furthermore, when the vehicle using driver assistance device 1 is a hybrid electric vehicle (HEV), the engine ECU can adjust the driving force of the vehicle generated by either or both of the "internal combustion engine and electric motor" that serve as the vehicle's drive source. Alternatively, when the vehicle using driver assistance device 1 is a battery electric vehicle (BEV), an electric motor ECU that adjusts the driving force of the vehicle generated by the "electric motor" that serves as the vehicle's drive source can be used instead of the engine ECU.

[0044] Braking device 40 applies braking force to the wheels (brake discs). Braking device 40 includes a brake ECU, brake calipers, etc. The brake caliper includes an actuator that presses the brake pads against the brake disc. The brake ECU obtains a target value for the braking force from other ECUs. The brake ECU controls the brake caliper actuator in a manner that makes the braking force applied to the wheels consistent with the target value.

[0045] Steering system 50 adjusts the steering wheel angle (left front wheel and right front wheel). Steering system 50 includes a steering ECU and a steering mechanism. Steering system 50 also includes an actuator (e.g., an electric motor) that drives the steering mechanism to change the steering angle, and a steering angle sensor that obtains the steering wheel angle (actual steering angle). ECU 10 determines a target value θt for the steering wheel angle θ (actual steering angle) based on various information obtained from onboard sensors 20. For example, ECU 10 determines the target value θt in a way that makes the vehicle travel along the lane. The steering ECU obtains the target value θt from ECU 10 and controls the actuator in a way that makes the actual steering angle output from the steering angle sensor consistent with the target value θt.

[0046] The notification device 60 includes an image display device and an audio device. The image display device is, for example, disposed on an instrument panel (e.g., near the speedometer). The image display device displays an image according to instructions received from the ECU 10. The audio device reproduces (emits) sound according to instructions received from the ECU 10.

[0047] The direction indicator 70 includes a lever, a lever sensor, turn indicator lights, and a drive circuit (turn signal ECU). The lever sensor includes a first switch and a second switch whose on / off states change according to the position of the lever. When the lever is in the neutral position, both the first and second switches are off. When the lever is in a first position (right turn indicator position), the first switch is on and the second switch is off. When the lever is in a second position (left turn indicator position), the first switch is off and the second switch is on. The drive circuit causes the right turn indicator light to flash when the first switch is on, and causes the left turn indicator light to flash when the second switch is on. Furthermore, the ECU 10 can obtain the on / off states of the first and second switches from the drive circuit. The ECU 10 can detect the operating status of the vehicle's turn indicator lights based on the on / off states of the first and second switches. Additionally, the direction indicator 70 has a function for forcibly returning the lever to the neutral position according to instructions from the ECU 10 (a device for forcibly turning off the turn indicator lights).

[0048] (Work)

[0049] When the ACC switch is on, the ECU10 determines whether the preceding vehicle V1 is present, as described below, and performs ACC processing to control the drive unit 30 and braking unit 40 (hereinafter referred to as "drive unit, etc.") of the vehicle based on the determination result. The ACC processing includes constant speed driving processing and inter-vehicle distance maintenance processing.

[0050] [Cruise Control Handling]

[0051] Based on information obtained from the vehicle sensors 20 (camera 21 and millimeter-wave radar 22), the ECU 10 determines whether a preceding vehicle V1 exists. If no preceding vehicle V1 exists, the ECU 10 controls the drive system and the like in a manner that makes the vehicle's speed sp0 consistent with a predetermined value spt (e.g., the speed at which fuel consumption is lowest).

[0052] [Workshop Distance Maintenance]

[0053] When ECU10 determines that a preceding vehicle V1 is present, it calculates the inter-vehicle distance D between the preceding vehicle V1 and the vehicle itself, as well as the vehicle speed sp1 of the preceding vehicle V1, based on information obtained from camera 21 and millimeter-wave radar 22. ECU10 then calculates the target distance Dt between the preceding vehicle and the vehicle speed sp0 of the preceding vehicle V1.

[0054] When the speed of the preceding vehicle V1 relative to the vehicle's speed sp0 is sp1 (relative speed vr = sp1 - sp0) is greater than 0, the inter-vehicle distance D gradually increases. When the inter-vehicle distance D has increased compared to the target distance Dt, the ECU 10 sets the target value of the vehicle's acceleration α to a predetermined value α1 (>0) so that the vehicle's speed sp0 becomes greater than the preceding vehicle V1's speed sp1. Furthermore, it controls the drive system and other components (acceleration control) to ensure that the vehicle's acceleration α (measured value) matches the predetermined value α1. As a result, the inter-vehicle distance D decreases, approaching the target distance Dt. Then, when the inter-vehicle distance D matches the target distance Dt, the ECU 10 sets the target value of the vehicle's acceleration α to 0. That is, the ECU 10 controls the drive system and other components to ensure that the vehicle travels at the same speed as the preceding vehicle V1.

[0055] On the other hand, when the relative speed vr is less than "0", the vehicle distance D gradually decreases. When the vehicle distance D has decreased compared to the target distance Dt, the ECU 10 sets the target value of acceleration α to a predetermined value α2 (<0) so that the vehicle speed sp0 of the current vehicle is less than the speed sp1 of the preceding vehicle V1. Furthermore, the ECU 10 controls the drive system (deceleration control) to make the vehicle's acceleration α (measured value) match the predetermined value α2 (<0). As a result, the vehicle distance D increases, approaching the target distance Dt. Then, when the vehicle distance D matches the target distance Dt, the ECU 10 sets the target value of the vehicle's acceleration α to "0".

[0056] Furthermore, the mapping representing the relationship between vehicle speeds sp0, sp1 and target distance Dt, or the parameters defining the formula for calculating the target distance Dtd, are stored in ROM10b. ECU10 determines the target distance Dt based on the aforementioned mapping or formula.

[0057] [Lane Keeping Assistance]

[0058] When the ACC switch is on and the LTA switch is on, the ECU 10 performs lane keeping operation (LTA) to control the steering device 50 so that the vehicle travels along lane L1 (the lane the vehicle is currently traveling in). Specifically, the ECU 10 controls the steering device 50 based on information obtained from the camera 21, in a state where it is located near the center of lane L1 in the width direction (for example, the difference Δd (=|ΔdL-ΔdR|) between the distance ΔdL between the left dividing line and the predetermined point on the left side of the vehicle and the distance ΔdR between the right dividing line and the predetermined point on the right side of the vehicle is less than a threshold Δdth), and the vehicle's orientation is approximately parallel to the extension direction of lane L1 (φ<φth). Here, the ECU 10 controls the steering device 50 so that the lateral acceleration of the vehicle when the vehicle turns due to the execution of this LTA operation is less than a predetermined upper limit value (setting a target value θt for the steering angle θ). Specifically, ECU10 has a mapping M that defines the relationship between vehicle speed sp0 and the upper limit θtmax of the target value θt. Referring to this mapping M, the upper limit θtmax corresponding to the current vehicle speed sp0 is obtained. Here, the mapping M is designed such that the larger the vehicle speed sp0, the smaller the upper limit θtmax. That is, when the vehicle speed sp0 is high, it is impossible to make the vehicle's turning radius too small. Therefore, there is a possibility that the vehicle may leave the lane during the process of correcting the vehicle's position and attitude relative to the lane by performing LTA processing (refer to...). Figure 4Furthermore, even at relatively low vehicle speeds (sp0), there are instances where the vehicle may detach from the lane during the process of correcting its position and attitude relative to the lane by performing LTA processing when the vehicle's posture relative to the lane deteriorates significantly (when the angle φ is too large).

[0059] When the ECU 10 detects that the vehicle has deviated from lane L1 (in a state where it has become part of the vehicle and overlaps with the lane markings when viewed from above) based on information obtained from the camera 21 and the navigation system 23, it terminates the lane keeping assist (LTA) process and sets the LTA switch to the off state. Furthermore, in this case, in addition to the LTA process, the ACC process can also be terminated, and the ACC switch can be set to the off state. Next, to prompt the driver to manually perform a driving operation that moves the vehicle towards the center of the lane in the width direction, the ECU 10 displays a predetermined image on the notification device 60 and reproduces a predetermined sound. Furthermore, the driver assistance device 1 may also have a lane departure suppression function, which, when a high probability of the vehicle deviating from the lane is detected, allows the lateral acceleration of the vehicle to increase to a certain extent, thereby controlling the steering device 50 to pull the vehicle back towards the center of the lane in the width direction.

[0060] During LTA processing, ECU 10 monitors the on / off state of the first and second switches of the direction indicator 70. When ECU 10 detects that the first or second switch of the direction indicator 70 changes from the off state to the on state (the left or right turn indicator light starts to work (flashes)), it temporarily stops (restricts) the execution of ACC and LTA processing. Furthermore, in this state, the ACC and LTA switches remain on, and ECU 10 can restart ACC and LTA processing if the conditions described later are met. Also in this state, the drive unit 30, braking unit 40, steering unit 50, etc., of the vehicle are controlled according to the driver's driving operations. For example, without the intervention of the driving assistance device 1, the driver can perform driving operations (lane change) to move the vehicle from lane L1 to lane L2R, which is the adjacent lane to the right of lane L1, or to lane L2L, which is the adjacent lane to the left of lane L1, according to the driver's intention.

[0061] Starting from the point when the ECU10 detects that the right (left) turn indicator light has started working and temporarily stops the execution of ACC and LTA processing, it sequentially performs a determination to see if the lane change from lane L1 to lane L2R (L2L) is complete. When the ECU10 detects, based on the information obtained from the camera 21, that all wheels of the vehicle have entered lane L2R (L2L), it determines that the lane change is complete.

[0062] Next, based on information obtained from camera 21 and navigation system 23, ECU 10 identifies the shape (curvature of the curve) of lane L2R (L2L), the vehicle's position (lateral position) relative to lane L2R (L2L), and its posture. Then, assuming that ACC processing and LTA processing begin again from the current time point (time point t0), ECU 10 calculates the area (predicted trajectory TR) that the vehicle will traverse up to time point t1, where the vehicle is positioned within a predetermined lateral range (Δd < Δdth) in lane L2R (L2L) and its orientation is approximately parallel to the extension direction of lane L2R (L2L) (φ < φth). Figure 3 and Figure 4 Here, ECU10 obtains the vehicle speed sp0 at time point t0 (hereinafter referred to as "vehicle speed sp0-a"). When calculating the predicted trajectory TR, ECU10 assumes that the vehicle travels at vehicle speed sp0-a (constant speed driving) during the period T from time point t0 to time point t1. In addition, ECU10 refers to the mapping M to obtain the upper limit value θtmax corresponding to vehicle speed sp0-a (hereinafter referred to as "upper limit value θtmax-a"). ECU10 obtains the shortest trajectory among the trajectories of the vehicle that satisfies the condition that "the vehicle travels at a constant speed of vehicle speed sp0-a during the period T, and the steering angle θ is less than or equal to the upper limit value θtmax-a" as the predicted trajectory TR.

[0063] In such Figure 3 As shown, if the predicted trajectory TR is in lane L2R (lane L2L) (without deviating), ECU 10 determines at time t0 that the conditions (cancellation conditions) for starting ACC processing and lane keeping assist processing have been met, and starts (restarts) these processes. Furthermore, ECU 10 stops (turns off) the turn indicator lights. By automatically stopping the turn indicator lights, the driver can recognize that ACC processing and LTA processing have resumed. That is, the driver can recognize that the driving operation has been delegated to the driver assistance device 1 to a certain extent. On the other hand, in situations such as... Figure 4 If the predicted trajectory TR deviates from lane L2R (lane L2L) as shown, ECU10 does not initiate (restart) ACC processing and lane keeping assist (LTA) processing. Additionally, in this situation, ECU10 does not stop the turn indicator lights from operating. By not automatically stopping the turn indicator lights, the driver can recognize that ACC processing and LTA processing have not yet restarted. That is, the driver can recognize that they are in a state where they must actively perform driving operations.

[0064] As described above, the driving assistance device 1 has a function that temporarily disables the ACC and LTA functions when a lane change from lane L1 to lane L2R (L2L) is initiated (temporary stop function), and a function that re-enables the ACC and LTA functions when the lane change is completed and the vehicle can travel along lane L2R (L2L) (restart function). Hereinafter, refer to... Figure 4 The program PR1 executed by the CPU10a (hereinafter referred to as "CPU") of ECU10 to perform these functions (temporary stop function and restart function) will be explained.

[0065] During the execution of ACC and LTA processing (when the ACC and LTA switches are in the ON state), the CPU executes according to a predetermined cycle. Figure 5 The program PR1 is shown. The CPU starts executing program PR1 from step 100, causing the process to proceed to step 101.

[0066] In step 101, the CPU determines whether the right (left) turn indicator light is active (flashing). If the CPU determines that the right (left) turn indicator light is active (101: Yes), the process proceeds to step 102. On the other hand, if the CPU does not determine that the right (left) turn indicator light is active (101: No), the process proceeds to step 107, and in step 107, the execution of program PR1 ends.

[0067] In step 102, the CPU temporarily suspends ACC and LTA processing. Then, the CPU proceeds to step 103.

[0068] In step 103, the CPU determines whether a lane change from lane L1 to lane L2R (L2L) has been completed. If the CPU determines that the lane change has been completed (103: Yes), the process proceeds to step 104. On the other hand, if the CPU does not determine that the lane change has been completed (103: No), the process returns to step 103. That is, the CPU repeatedly executes step 103 during the process of completing the lane change.

[0069] In step 104, the CPU determines whether the predicted trajectory TR is within (converged into) lane L2R (L2L) (whether the release condition for lifting the restrictions of ACC and LTA processing is met). If the CPU determines that the predicted trajectory TR is within lane L2R (L2L) (104: Yes), the process proceeds to step 105. On the other hand, if the CPU does not determine that the predicted trajectory TR is within lane L2R (L2L) (104: No), the process returns to step 104. That is, the CPU repeatedly executes step 104 until the release condition is met. The driver manually moves the vehicle towards the center of lane L2R (L2L) in the width direction. During this process, the predicted trajectory TR is updated sequentially. And, when the release condition is met during this process, the CPU causes the process to proceed to step 105.

[0070] In step 105, the CPU stops the operation of the right (left) turn indicator light. Then, the CPU proceeds to step 106.

[0071] In step 106, the CPU restarts ACC and LTA processing. Then, the CPU moves the processing to step 107, where the execution of program PR1 ends.

[0072] Furthermore, it is conceivable that during the repeated execution of step 103 by the CPU, the driver intends to interrupt the lane change (manually turning off the turn indicator light). In this case, the CPU forcibly terminates the execution of program PR1 and turns the ACC switch and LTA switch to the off state. Additionally, it is conceivable that during the repeated execution of step 104 by the CPU, the vehicle leaves lane L2R (L2L). In this situation, the CPU forcibly terminates the execution of program PR1 and turns the ACC switch and LTA switch to the off state. Furthermore, the CPU can, upon forcibly terminating the execution of program PR1, cause the notification device 60 to display a predetermined image and reproduce (emit) a predetermined sound.

[0073] (Effect)

[0074] In conventional devices, where LTA processing is restarted at the point where a lane change from lane L1 to lane L2R (L2L) is completed, sometimes the vehicle will leave lane L2R (L2L) shortly afterward, forcing the interruption of LTA processing (and ACC processing). In the driving assistance device 1 of this embodiment, when the ECU 10 determines that a lane change from lane L1 to lane L2R (L2L) has been completed, and when the condition for controlling the vehicle in a manner that allows it to travel along lane L2R (L2L) (the condition for releasing the restrictions on ACC processing and LTA processing) is met (when the predicted trajectory TR is in lane L2R (L2L)), it restarts ACC processing and LTA processing. This prevents situations where, although LTA processing is restarted in lane L2R (L2L), the vehicle is forced to exit LTA processing (leaving lane L2R (L2L)) shortly afterward. That is, according to the driving assistance device 1, after the lane change is completed, the LTA process is restarted at an appropriate time. Furthermore, the turn indicator lights are automatically stopped (turned off) when the release condition is met. Thus, the driver can recognize that "lane keeping assist has restarted." In other words, the driver can recognize that "the driver is in a state where driving operations (steering) can be delegated to the driving assistance device to a certain extent."

[0075] <Variation Example>

[0076] As described above, when the ECU 10 detects that the right (left) turn signal indicator has started operating, it temporarily suspends the execution of ACC and LTA processing. From this point onwards, during the period before the lane change to lane L2R (L2L) is completed, the ECU 10 sequentially obtains information from the camera 21 and the millimeter-wave radar 22, and based on this information, sequentially determines whether it is difficult to execute LTA processing at lane L2R (L2L) (whether the cancellation condition is met). If the ECU 10 determines that the cancellation condition is met, it forcibly turns off the turn signal indicator. That is, the driver assistance device 1 can also have the function of proposing to the driver to interrupt the lane change. Furthermore, for example, the ECU 10 determines that the cancellation condition is met when it detects that the width W of lane L2R (L2L) is below a threshold (extremely narrow road width) or when it detects an obstacle (falling object) in lane L2R (L2L).

Claims

1. A driving assist device characterized by comprising: Possessing: an in-vehicle sensor including a sensor for acquiring a position of a host vehicle with respect to a lane in which the host vehicle is traveling and a sensor for acquiring a vehicle speed of the host vehicle; and a processor configured to be able to execute a lane maintenance process for controlling the host vehicle in such a manner that the host vehicle travels along the lane, the processor is configured to in a case where it is determined that the host vehicle has completed a lane change from a first lane to a second lane adjacent to the first lane, continuously restrict execution of the lane maintenance process until the host vehicle becomes able to execute the lane maintenance process in the second lane.

2. The driving assistance device according to claim 1, characterized in that the processor is further configured to determine that the lane change from the first lane to the second lane has been completed in a case where it is detected, based on information acquired from the in-vehicle sensor, that all wheels of the host vehicle have entered the second lane.

3. The driving assistance device according to claim 1, characterized in that the processor is further configured to restrict execution of the lane maintenance process in a case where a direction indicator of the host vehicle has started to operate in a situation where the host vehicle is traveling in the first lane.

4. The driving assistance device according to any one of claims 1 to 3, characterized in that the in-vehicle sensor further includes a sensor for acquiring a posture of the host vehicle with respect to the lane in which the host vehicle is traveling, the processor is further configured to in a case where it is determined that the lane change has been completed, assume that the lane maintenance process is started again from a current time point, calculate a predicted trajectory of an area through which the host vehicle is predicted to pass until a predetermined condition related to a position and a posture of the host vehicle with respect to the second lane is satisfied by execution of the lane maintenance process, in a case where the predicted trajectory is within the second lane, release the restriction on execution of the lane maintenance process.

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