Driving control device

Abstract

To stabilize behavior of an own vehicle.SOLUTION: A travel control device comprises one or a plurality of processors. The processor comprises an operation support control part that, when a vehicle preceding is switched to another vehicle, sets a control target point so that a vehicle to be followed is gradually switched from the vehicle preceding before the switch to the other vehicle preceding after the switch, and causes to perform steering control so that an own vehicle follows the set control target point.SELECTED DRAWING: Figure 6

Description

[Technical Field]

[0001] The present invention relates to a cruise control device mounted on a vehicle. [Background technology]

[0002] Conventionally, in vehicles such as automobiles, there is known a leading control device that uses radar or the like to detect objects in front of the vehicle, selects a leading vehicle that the vehicle should follow from among the detected objects, and drives the vehicle by following the selected leading vehicle. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2015-71361 Summary of the Invention [Problem to be solved by the invention]

[0004] In the above-described cruise control device, for example, if another vehicle cuts in between the host vehicle and the preceding vehicle, the other vehicle that has cut in becomes the preceding vehicle to be followed. In such a case, if the host vehicle performs steering control to follow the cutting in, there is a risk that the behavior of the host vehicle will become unstable, such as unintended steering.

[0005] Therefore, an object of the present invention is to stabilize the behavior of the host vehicle. [Means for solving the problem]

[0006] A cruise control device according to one embodiment of the present invention includes one or more processors, and when the preceding vehicle is switched, the processor No. 1 From the preceding vehicle, after switching No. 2 A driving assistance control unit that sets a control target point so that the subject vehicle is gradually switched to follow the preceding vehicle, and performs steering control so that the subject vehicle follows the set control target point. wherein the driving assistance control unit sets the control target point by adding a difference between the position of the first leading vehicle immediately before switching and the position of the second leading vehicle at the time of switching to a current position of the second leading vehicle, calculates an asymptotic time for making the difference zero based on a headway time required for the host vehicle to travel from the host vehicle to the first leading vehicle immediately before switching, and reduces the difference to asymptotically zero each time the steering control is repeatedly performed over the calculated asymptotic time. . This allows the cruise control device to perform steering control so that the control target gradually shifts from the preceding vehicle before the switch to the preceding vehicle after the switch. [Effects of the Invention]

[0007] According to the present invention, the behavior of the host vehicle can be stabilized. [Brief explanation of the drawings]

[0008] [Figure 1] 1 is a diagram showing a vehicle equipped with a cruise control device; [Figure 2] FIG. 2 is a diagram showing the configuration of a driving control device. [Figure 3] FIG. 2 is a diagram illustrating an outline of steering control for following a preceding vehicle. [Figure 4] FIG. 2 is a diagram illustrating an outline of steering control for following a preceding vehicle. [Figure 5] 10A and 10B are diagrams illustrating steering control for following a leading vehicle when only a leading vehicle is traveling along a curve. [Figure 6] 10A and 10B are diagrams illustrating a steering control for following a preceding vehicle according to an embodiment. [Figure 7] 4 is a flowchart showing a flow of processing for steering control to follow a preceding vehicle according to an embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0009] <1. Configuration of driving control device 1> Fig. 1 is a diagram showing a vehicle 100 equipped with a cruise control device 1. Fig. 2 is a diagram showing the configuration of the cruise control device 1. As shown in Fig. 1, the cruise control device 1 is equipped in the vehicle 100 and controls the cruise of the vehicle 100. Although FIG. 1 shows only a portion of the driving control device 1, in reality the driving control device 1 includes other components.

[0010] As shown in FIG. 2, the driving control device 1 includes an imaging unit 2, an image processing unit 3, a memory 4, a driving assistance control unit 5, a display control unit 6, an engine control unit 7, a transmission control unit 8, a brake control unit 9, a steering control unit 10, a display unit 11, an engine-related actuator 12, a transmission-related actuator 13, a brake-related actuator 14, a steering-related actuator 15, a sensor 16, a bus 17, and a communication unit 18.

[0011] The driving assistance control unit 5, the display control unit 6, the engine control unit 7, the transmission control unit 8, the brake control unit 9, and the steering control unit 10 are connected to one another via a bus 17.

[0012] The image processing unit 3 is configured by a microcomputer equipped with, for example, a CPU (Central Processing Unit: Processor), ROM (Read Only Memory), RAM (Random Access Memory), etc., and performs predetermined image processing related to recognition of the environment outside the vehicle based on image data obtained by capturing images of the traveling direction (forward in this example) and sides of the vehicle by the imaging unit 2. The image processing by the image processing unit 3 is performed using a memory 4, which is, for example, a non-volatile memory.

[0013] The imaging unit 2 is, for example, a stereo camera, and is provided with two cameras that capture images in approximately the same direction. Each camera is configured with a camera optical system and an imaging element such as a CCD (Charge Coupled Device) or a CMOS (Complementary Metal Oxide Semiconductor), and the camera optical system forms an image of the subject on the imaging surface of the imaging element, and an electrical signal corresponding to the amount of received light is obtained for each pixel.

[0014] Each camera is installed so as to enable distance measurement by the so-called stereo imaging method. The electrical signals obtained by each camera are subjected to A / D conversion and predetermined correction processing, and are supplied to an image processing unit 3 as digital image signals (image data) representing brightness values ​​at predetermined gradations on a pixel-by-pixel basis.

[0015] The imaging unit 2 may be configured with a single camera equipped with an imaging element capable of measuring distances. The imaging unit 2 may also be configured with a camera that images the area in front of the vehicle 100, a camera that images the area behind the vehicle 100, a camera that images the area to the side of the vehicle 100, and the like.

[0016] The image processing unit 3 performs various image processing based on image data obtained by stereo imaging, recognizes forward information such as three-dimensional objects and dividing lines (center lines, lane boundaries, etc.) ahead of the vehicle, and recognizes the road and lane on which the vehicle is traveling (the vehicle's travel path) based on this recognition information, etc. Furthermore, the image processing unit 3 recognizes a preceding vehicle to be followed based on the recognized three-dimensional objects, etc.

[0017] Specifically, the image processing unit 3 performs the following processing, for example, based on the stereoscopically captured image data. First, the image processing unit 3 generates distance information for each pixel from the amount of displacement (parallax) between corresponding positions for a pair of captured images as image data, using the principle of triangulation. Then, the image processing unit 3 performs a well-known grouping process on the distance information, and compares the grouped distance information with pre-stored three-dimensional road shape data and three-dimensional object data, etc., to recognize white lines, guardrails along the road, side walls such as curbs, three-dimensional objects such as vehicles, stop lines, traffic signals, railroad crossings, crosswalks, lanes, etc.

[0018] Furthermore, the image processing unit 3 recognizes a recognized vehicle located ahead as a preceding vehicle when the overlap ratio of the recognized vehicle located ahead is equal to or greater than a predetermined value. The overlap ratio indicates the degree of lateral overlap between the lateral position of the vehicle 100 and the vehicle located ahead. The overlap ratio is 100% when the vehicle located ahead is completely overlapped with the vehicle 100, 50% when they are located so that half the width of the vehicle body overlaps, and 0% when the width of the vehicle body does not overlap.

[0019] In this way, the image processing unit 3 can recognize surrounding objects and also recognize their behavior based on the image captured by the imaging unit 2. For example, the image processing unit 3 can also recognize the position, speed, acceleration (positive and negative acceleration due to acceleration or deceleration), change in traveling direction, blinking of blinkers, etc. of the preceding vehicle relative to the host vehicle 100.

[0020] The image processing unit 3 recognizes the above-mentioned various types of external environment information for each frame of image data, for example, and stores (holds) the recognized information in the memory 4 one by one.

[0021] The driving assistance control unit 5 is composed of, for example, a microcomputer equipped with a CPU, ROM, RAM, etc., and performs various driving assistance controls for driving assistance based on the results of image processing by the image processing unit 3 stored in the memory 4, detection signals obtained by the sensor 16, operation input information, etc., and communication information by the communication unit 18.

[0022] The driving assistance control unit 5 is connected to each of the control units, which are also configured with a microcomputer, namely a display control unit 6, an engine control unit 7, a transmission control unit 8, a brake control unit 9, and a steering control unit 10, via a bus 17, and is capable of mutual data communication with each of these control units. The driving assistance control unit 5 issues instructions to the necessary control units among the above control units to perform operations related to driving assistance.

[0023] Examples of driving assistance control that the driving assistance control unit 5 may perform include lane keeping control, autonomous emergency braking (AEB), adaptive cruise control (ACC), and adaptive cruise control (ADAP). Note that lane keeping control, autonomous emergency braking (AEB), and adaptive cruise control can be realized by known methods, and therefore a description thereof will be omitted. Further, adaptive cruise control will be described in detail later.

[0024] The display control unit 6 controls the display operation of the display unit 11 based on a detection signal from the sensor 16, operation input information from an operator, or instructions from the driving assistance control unit 5. For example, the display control unit 6 is capable of causing the display unit 11 to display a predetermined attention message as part of driving assistance based on instructions from the driving assistance control unit 5.

[0025] The display unit 11 collectively refers to various meters such as a speedometer and a tachometer provided in a meter panel installed in front of the driver, the MFD, and a display device for presenting information to the driver. The MFD can simultaneously or switchably display various information such as the total mileage of the vehicle, outside temperature, and instantaneous fuel consumption.

[0026] The engine control unit 7 controls various actuators provided as engine-related actuators 12 based on detection signals from sensors 16, operation input information from operators, instructions from the driving assistance control unit 5, or the like.

[0027] The engine-related actuators 12 include various actuators related to engine driving, such as a throttle actuator that drives a throttle valve and an injector that injects fuel.

[0028] For example, the engine control unit 7 controls the start / stop of the engine in response to the operation of an ignition switch. The engine control unit 7 also controls the fuel injection timing, fuel injection pulse width, throttle opening, etc. based on detection signals from predetermined sensors such as an engine rotation speed sensor 16c and an accelerator opening sensor 16d, which will be described later. In addition, the engine control unit 7 determines the target throttle opening from, for example, a map, based on the required torque calculated and output by the driving assistance control unit 5 based on the target acceleration and the gear ratio of the transmission, and controls the throttle actuator (controls the engine output) based on the determined throttle opening.

[0029] The transmission control unit 8 controls various actuators provided as transmission-related actuators 13 based on detection signals from sensors 16, operation input information from operators, instructions from the driving assistance control unit 5, or the like. The transmission-related actuator 13 is, for example, an actuator for controlling the shifting of an automatic transmission.

[0030] For example, the transmission control unit 8 outputs a predetermined shift signal to the transmission-related actuator 13 to perform shift control. When the automatic transmission is a CVT (Continuously Variable Transmission), the gear ratio is continuously changed as the gear change control.

[0031] The brake control unit 9 controls various actuators provided as brake-related actuators 14 based on detection signals from sensors 16, operation input information from an operator, or instructions from the driving assistance control unit 5, etc. The brake-related actuator 14 includes various brake-related actuators, such as a hydraulic pressure control actuator for controlling the output hydraulic pressure from the brake booster to the master cylinder and the hydraulic pressure in the brake fluid pipes.

[0032] For example, the brake control unit 9 controls the hydraulic pressure control actuator to brake the vehicle based on hydraulic pressure instruction information output from the driving assistance control unit 5. The brake control unit 9 also calculates the slip ratio of the wheels based on detection signals from predetermined sensors (for example, an axle rotation speed sensor or a vehicle speed sensor 16a), and increases or decreases the hydraulic pressure using the hydraulic pressure control actuator according to the slip ratio, thereby realizing so-called ABS (Antilock Brake System) control.

[0033] The steering control unit 10 controls various actuators provided as steering-related actuators 15 based on detection signals from sensors 16, operation input information from an operator, or instructions from the driving assistance control unit 5, etc. As the steering-related actuator 15, for example, an actuator for steering steered wheels such as front wheels is provided.

[0034] For example, the steering control unit 10 steers the steered wheels by controlling the steering-related actuator 15 based on the steering angle detected by a steering angle sensor 16f (described later). The steering control unit 10 also realizes automatic steering by controlling the steering-related actuator 15 based on instruction information provided from the driving assistance control unit 5.

[0035] The sensor 16 collectively represents various sensors provided on the vehicle 100, which is the host vehicle. The sensors 16 include a vehicle speed sensor 16a, a wheel speed sensor 16b, an engine rotation speed sensor 16c, an accelerator opening sensor 16d, a brake sensor 16e, a steering angle sensor 16f, a yaw rate sensor 16g, a G sensor 16h, a millimeter wave radar 16i, and a position information receiver 16j. Note that these are merely examples, and various other sensors may be provided.

[0036] The vehicle speed sensor 16a detects the speed of the vehicle. The wheel speed sensor 16b detects the rotation speed of the wheel. The engine speed sensor 16c detects the engine speed. The accelerator opening sensor 16d detects the accelerator opening from the amount of depression of the accelerator pedal. The brake sensor 16e detects the amount of braking operation from the amount of depression of the brake pedal. The steering angle sensor 16f detects the steering angle of the steering wheel. The yaw rate sensor 16 g detects the yaw rate applied to the vehicle 100 . The G sensor 16h detects acceleration acting on the vehicle 100 in the traveling direction, the width direction, and the vertical direction. The millimeter wave radar 16i detects the surrounding situation by emitting millimeter waves to the outside and performing sensing. The position information receiver 16j is, for example, a receiver for a Global Navigation Satellite System (GNSS) or a receiver that receives information from a roadside device, and acquires current position information.

[0037] Various detection signals from the sensor 16 are supplied to the necessary parts, such as the image processing part 3, the driving assistance control part 5, the display control part 6, the engine control part 7, the transmission control part 8, the brake control part 9, and the steering control part 10.

[0038] The communication unit 18 performs vehicle-to-vehicle communication, network communication with an external device such as a server, and receives GNSS (Global Navigation Satellite System) signals. For example, the driving assistance control unit 5 can acquire information about other vehicles received by the communication unit 18. The communication unit 18 can also acquire various types of information, such as surrounding environment information about the current location and road information, through network communication such as the Internet.

[0039] <2. Leading vehicle following steering control> The steering control for following the preceding vehicle according to the embodiment will be described. In the following description, the vehicle 100 in the above configuration will be referred to as the "host vehicle 100" to distinguish it from the preceding vehicle 200.

[0040] When the image processing unit 3 cannot identify the lane in which the vehicle 100 is traveling while the ACC is being executed and lane keeping control cannot be performed, the driving assistance control unit 5 performs steering control to follow the preceding vehicle instead of lane keeping control. However, the steering control to follow the preceding vehicle may be executed when the ACC is not being executed, or may be executed with priority over lane keeping control while the ACC is being executed.

[0041] Here, first, the steering control to follow the leading vehicle of a comparative example will be described, and then the processing of the steering control to follow the leading vehicle in the embodiment will be described. Note that the steering control to follow the leading vehicle in the comparative example and the embodiment is executed every time an image is captured by the imaging unit 2 and image processing is performed by the image processing unit 3, and the interval is defined as processing time t. Therefore, the steering control to follow the leading vehicle is executed every processing time t.

[0042] [2.1 Comparative example of steering control to follow the preceding vehicle] 3 and 4 are diagrams illustrating an overview of the steering control for following the preceding vehicle. Fig. 3 is a diagram illustrating a case where the host vehicle 100 and the preceding vehicle 200 are traveling straight. Fig. 4 is a diagram illustrating a case where the host vehicle 100 and the preceding vehicle 200 are traveling with a constant radius of curvature.

[0043] As shown in Figures 3 and 4, the driving assistance control unit 5 acquires information indicating the position (X, Z) of the preceding vehicle 200 in the XZ coordinate system based on an origin O, which is a predetermined position of the vehicle 100, stored in the memory 4 as a result of image processing by the image processing unit 3. Here, the origin O is set, for example, at the center in the lateral direction (left and right direction) of the host vehicle 100 and at the leading edge in the traveling direction. In the XZ coordinate system, the X axis direction is the direction along the lateral direction of the host vehicle 100, with the right direction being the positive direction, and the Z axis direction is the direction along the longitudinal direction of the host vehicle 100, with the forward direction being the positive direction.

[0044] The driving assistance control unit 5 sets the acquired position of the leading vehicle 200 as a control target point, and calculates the curvature k using equation (1).

number

[0045] The driving assistance control unit 5 instructs the steering control unit 10 to make the host vehicle 100 travel at the calculated curvature k. That is, the driving assistance control unit 5 causes the steering control unit 10 to perform steering control to drive the steering-related actuator 15 so that the host vehicle 100 travels at the calculated curvature k.

[0046] 3, when the host vehicle 100 and the preceding vehicle 200 are traveling straight, the curvature k in equation (1) is approximately 0, and therefore the driving assistance control unit 5 performs steering control so that the host vehicle 100 travels approximately straight. This enables the host vehicle 100 to follow the preceding vehicle 200 while traveling straight.

[0047] 4, when the host vehicle 100 and the preceding vehicle 200 are traveling at a constant radius of curvature, the driving assistance control unit 5 performs steering control so that the host vehicle 100 makes a curve at a curvature k, which is the reciprocal of the constant radius of curvature. This enables the host vehicle 100 to follow the preceding vehicle 200 while making a curve at a constant radius of curvature.

[0048] FIG. 5 is a diagram illustrating the steering control for following the preceding vehicle when the preceding vehicle 200 is switched. Now, suppose that, while the preceding vehicle following steering control is being performed with the preceding vehicle 200 as the following target, another vehicle enters (cuts in) between the host vehicle 100 and the preceding vehicle 200. In such a case, the image processing unit 3 recognizes the other vehicle that has entered as the new preceding vehicle 200. In the following description, the new leading vehicle 200 will be referred to as a new leading vehicle 200a, and the leading vehicle 200 that was the target to be followed up until the new leading vehicle 200a was recognized will be referred to as an old leading vehicle 200b.

[0049] When the new leading vehicle 200a is recognized, if the curvature k is calculated based on equation (1) and steering control is performed so that the vehicle 100 travels at the calculated curvature k, the behavior of the vehicle 100 may become unstable, such as turning to approach the new leading vehicle 200a, as shown by the dashed line in Figure 5.

[0050] Therefore, in the embodiment of the preceding vehicle following steering control, when the preceding vehicle 200 switches, a control target point is set so that the target to be followed is gradually switched from the preceding vehicle 200 before the switch to the preceding vehicle 200 after the switch, and steering control is performed so that the host vehicle 100 follows the set control target point.

[0051] 2.2 Leading vehicle following steering control in the embodiment 6 is a diagram illustrating the steering control for following the preceding vehicle in the embodiment. Specifically, the driving assistance control unit 5 acquires information indicating the position (X, Z) of the preceding vehicle 200 from the memory 4. At this time, the driving assistance control unit 5 also acquires the object ID of the preceding vehicle 200. The object ID is an ID that is uniquely assigned to a three-dimensional object recognized by the image processing unit 3.

[0052] The driving assistance control unit 5 determines whether the preceding vehicle 200 has been switched based on the object ID of the preceding vehicle 200. If the preceding vehicle 200 has been switched, the driving assistance control unit 5 calculates the differences (dX, dZ) in the X-axis direction and the Z-axis direction between the new preceding vehicle 200a and the old preceding vehicle 200b based on the initial position (X, Z) of the new preceding vehicle 200a acquired this time and the final position (X, Z) of the old preceding vehicle 200b acquired last time.

[0053] Specifically, the driving assistance control unit 5 calculates the difference (dX, dZ) by subtracting the initial position (X, Z) of the new preceding vehicle 200a from the final position (X, Z) of the old preceding vehicle 200b. Note that the difference (dX, dZ) calculated here is the difference immediately after the preceding vehicle 200 is switched, and as shown by the arrow line in Fig. 6, it is subtracted and becomes shorter each time the preceding vehicle following steering control is performed.

[0054] In addition, the driving assistance control unit 5 calculates the inter-vehicle time required to travel the distance to the previous preceding vehicle 200b by dividing the distance (position) in the Z-axis direction to the previous preceding vehicle 200b by the speed of the host vehicle 100.

[0055] Next, the driving assistance control unit 5 calculates the asymptotic time based on the calculated inter-vehicle time by referring to the asymptotic time map stored in the memory 4. Here, the asymptotic time map associates the asymptotic time with the inter-vehicle time. The asymptotic time is the time required to switch the vehicle to be followed from the old leading vehicle 200b to the new leading vehicle 200a, and is set to become shorter as the inter-vehicle time becomes longer.

[0056] Then, the driving assistance control unit 5 calculates the number of times the steering control to follow the preceding vehicle is executed corresponding to the asymptotic time (asymptotic time / processing time), and calculates the subtraction amount (sX, sZ) for subtracting the difference (dX, dZ) for each execution of the steering control to follow the preceding vehicle by dividing the difference (dX, dZ) by the number of times the control is executed.

[0057] Thereafter, the driving assistance control unit 5 subtracts the subtraction amount (sX, sZ) from the difference (dX, dZ), thereby reducing the difference (dX, dZ) each time the steering control to follow the leading vehicle is executed. According to this calculation, the difference (dX, dZ) is linearly subtracted by the subtraction amount (sX, sZ) each time the steering control to follow the leading vehicle is executed, and becomes 0 when the steering control to follow the leading vehicle has been executed the specified number of times.

[0058] The driving assistance control unit 5 then sets the position obtained by adding the difference (dX, dZ) to the currently acquired position (X, Z) of the new preceding vehicle 200a as the control target point (X', Z'). In other words, the driving assistance control unit 5 sets the control target point so that the difference (dX, dZ) between the positions of the preceding vehicle 200 before and after the switch asymptotically approaches zero.

[0059] Therefore, the control target point (X', Z') is set so that the object to be followed gradually switches from the old leading vehicle 200b to the new leading vehicle 200a over an asymptotic time, as shown by the black circle in Figure 6, with the point in time when the preceding vehicle 200 to be controlled switches as the reference.

[0060] Thereafter, the driving assistance control unit 5 calculates the curvature k by substituting the control target points (X', Z') for X and Z in equation (1). The driving assistance control unit 5 causes the steering control unit 10 to perform steering control to drive the steering-related actuator 15 so that the host vehicle 100 travels with the curvature k, as shown by the dashed dotted line in Fig. 6.

[0061] As a result, even when the preceding vehicle 200 is switched, the position of the new preceding vehicle 200a is not immediately set as the control target point, but the control target point gradually shifts from the position of the old preceding vehicle 200b to the position of the new preceding vehicle 200a.

[0062] Therefore, the driving assistance control unit 5 can prevent the host vehicle 100 from deviating from its normal behavior, such as suddenly turning when traveling straight.

[0063] 7 is a flowchart showing the processing flow of the steering control to follow the preceding vehicle. As shown in Fig. 7, when the steering control to follow the preceding vehicle is started, in step S1 the driving assistance control unit 5 acquires information about the preceding vehicle 200 from the memory 4. Here, the position of the preceding vehicle 200, the object ID of the preceding vehicle 200, etc. are acquired.

[0064] In step S2, the driving assistance control unit 5 determines whether the preceding vehicle has been switched. If the preceding vehicle 200 has been switched (Yes in step S2), the driving assistance control unit 5 calculates the inter-vehicle time in step S3, calculates the asymptotic time in step S4, and calculates the difference (dX, dZ) and the subtraction amount (sX, sZ) in step S5. In addition, in step S6, the driving assistance control unit 5 sets a switching in-progress flag indicating that the preceding vehicle 200 to be controlled is in the process of being switched.

[0065] Thereafter, in step S7, the driving assistance control unit 5 calculates the control target point (X', Z') by subtracting the subtraction amount from the difference (dX, dZ) and adding the result to the position of the new leading vehicle 200a. Also, in step S8, the driving assistance control unit 5 calculates the curvature k by substituting the control target point (X', Z') for X and Z in equation (1). Then, in step S9, the driving assistance control unit 5 causes the steering control unit 10 to perform steering control to drive the steering-related actuator 15 so that the host vehicle 100 travels with the curvature k.

[0066] On the other hand, if the preceding vehicle 200 has not switched (No in step S2), the driving assistance control unit 5 determines in step S10 whether the switching flag is set. As a result, if the switching flag is not set (No in step S10), the process proceeds to step S8. In this case, the position (X, Z) of the preceding vehicle 200 is substituted into equation (1) as the control target point to calculate the curvature k.

[0067] If the switching in progress flag is set (Yes in step S10), the driving assistance control unit 5 determines whether the asymptotic time has elapsed in step S11. If the asymptotic time has not elapsed (No in step S11), the driving assistance control unit 5 proceeds to step S7, and if the asymptotic time has elapsed (Yes in step S11), the driving assistance control unit 5 clears the switching in progress flag in step S12 and proceeds to step S8.

[0068] <3. Modifications> The above embodiment is merely an example of how the present invention can be implemented, and the present invention is not limited to the above example, and various modifications are possible.

[0069] For example, in the preceding vehicle following steering control in the above-described embodiment, the asymptotic time is calculated based on the inter-vehicle time. However, the asymptotic time may be calculated based on the distance to the previous preceding vehicle 200b (inter-vehicle distance). In this case, the asymptotic time may be set to be shorter as the inter-vehicle distance becomes longer.

[0070] 7 may be stored in a storage medium such as a nonvolatile memory in the driving assistance control unit 5 or a nonvolatile memory provided in the driving control device 1. The program may also be stored in a portable storage medium, or may be downloaded to the vehicle 100 from a server device via network communication.

[0071] Furthermore, the image processing unit 3, the driving assistance control unit 5, the display control unit 6, the engine control unit 7, the transmission control unit 8, the brake control unit 9, and the steering control unit 10 are configured by different microcomputers, but they may be configured by a single microcomputer. Furthermore, some of the image processing unit 3, the driving assistance control unit 5, the display control unit 6, the engine control unit 7, the transmission control unit 8, the brake control unit 9, and the steering control unit 10 may be configured by a single microcomputer.

[0072] <4. Summary> As described above, the driving control device 1 of the embodiment is equipped with a driving assistance control unit 5 that sets a control target point (X', Z') so that, when the preceding vehicle 200 switches, the target to be followed is gradually switched from the preceding vehicle before the switch (old preceding vehicle 200b) to the preceding vehicle after the switch (new preceding vehicle 200a), and performs steering control so that the host vehicle 100 follows the set control target point. This allows the cruise control device 1 to perform steering control such that the control target gradually shifts from the preceding vehicle before the switch to the preceding vehicle after the switch. Therefore, the cruise control device 1 can stabilize the behavior of the host vehicle 100.

[0073] In addition, the driving assistance control unit 5 may set a control target point (X', Z') by adding the difference (dX, dZ) between the position of the preceding vehicle before the switch (old preceding vehicle 200b) and the position of the preceding vehicle after the switch (new preceding vehicle 200a) to the position of the preceding vehicle after the switch (new preceding vehicle 200a), and may cause the difference to gradually approach zero. This allows the control target point (X', Z') to gradually approach the position of the new leading vehicle 200a from the position of the old leading vehicle 200b, making it possible to further stabilize the behavior of the host vehicle 100.

[0074] In addition, the driving assistance control unit 5 may calculate the asymptotic time for making the difference (dX, dZ) between the inter-vehicle distance to the preceding vehicle (old preceding vehicle 200b) before the switchover zero based on the inter-vehicle time during which the subject vehicle 100 travels, and may use the calculated asymptotic time to make the difference asymptotic to zero. This makes it possible to set an optimal asymptotic time according to the inter-vehicle time, and to make the difference asymptotic to 0 using an asymptotic time that varies depending on the inter-vehicle time. In other words, the target to be followed can be shifted optimally according to the inter-vehicle time, and the behavior of the host vehicle 100 can be made more stable.

[0075] It is also possible that the longer the inter-vehicle time, the shorter the asymptotic time. Here, if the inter-vehicle time or inter-vehicle distance is long, the cutting-in vehicle (new leading vehicle 200a) can cut in without taking much time. On the other hand, if the inter-vehicle time or inter-vehicle distance is short, the cutting-in vehicle (new leading vehicle 200a) will take time to cut in slowly. Therefore, by shortening the asymptotic time as the inter-vehicle time increases, it becomes possible to set the asymptotic time in accordance with the behavior of the vehicle cutting in. In other words, it is possible to optimally shift the target to be followed in accordance with the behavior of the vehicle cutting in, thereby making the behavior of the host vehicle 100 more stable.

[0076] In addition, the driving assistance control unit 5 may calculate the asymptotic time to make the difference zero based on the inter-vehicle distance to the preceding vehicle (old preceding vehicle 200b) before the switch, and may use the calculated asymptotic time to make the difference asymptotic to zero. This makes it possible to set an optimal asymptotic time according to the inter-vehicle distance, and to use an asymptotic time that varies depending on the inter-vehicle distance to make the difference asymptotic to 0. In other words, the target to be followed can be shifted optimally according to the inter-vehicle distance, making it possible to further stabilize the behavior of the host vehicle 100. [Explanation of symbols]

[0077] 1. Driving control device 2. Imaging unit 3 Image processing section 5. Driving assistance control unit 10 Steering control unit 100 Vehicles (own vehicle) 200 Leading vehicle 200a New Leading Vehicle 200b Old leading vehicle

Claims

1. one or more processors; The processor: a driving assistance control unit that, when the preceding vehicle is switched, sets a control target point so that the target to be followed is switched in stages from a first preceding vehicle before the switch to a second preceding vehicle after the switch, and performs steering control so that the host vehicle follows the set control target point; The driving assistance control unit setting the control target point by adding a difference between the position of the first leading vehicle immediately before the switch and the position of the second leading vehicle at the time of the switch to the current position of the second leading vehicle; An asymptotic time for making the difference between the vehicle distance from the host vehicle to the first preceding vehicle immediately before switching to zero is calculated based on the inter-vehicle time required for the host vehicle to travel, and the difference is reduced and made to asymptotically approach zero each time the steering control is repeatedly executed over the calculated asymptotic time. Driving control device.

2. The longer the inter-vehicle time, the shorter the asymptotic time The cruise control device according to claim 1 .

3. one or more processors; The processor: a driving assistance control unit that, when the preceding vehicle is switched, sets a control target point so that the target to be followed is switched in stages from a first preceding vehicle before the switch to a second preceding vehicle after the switch, and performs steering control so that the host vehicle follows the set control target point; The driving assistance control unit setting the control target point by adding a difference between the position of the first leading vehicle immediately before the switch and the position of the second leading vehicle at the time of the switch to the current position of the second leading vehicle; An asymptotic time for making the difference zero is calculated based on the inter-vehicle distance from the host vehicle to the first preceding vehicle immediately before switching, and the difference is reduced to asymptotically approach zero each time the steering control is repeatedly executed over the calculated asymptotic time. Driving control device.

Images