CONTROL DEVICE OF VEHICLE AND CONTROL METHOD OF VEHICLE

A processor of an ECU includes: a deceleration amount calculation unit that calculates a first deceleration amount for controlling deceleration of a vehicle during vehicle driving in an automatic driving mode; a deceleration amount acquisition unit that acquires a second deceleration amount of the vehicle according to an operation of a brake pedal when a driver operates the brake pedal; a deceleration control unit that controls deceleration of the vehicle by using a greater value of the first deceleration amount and the second deceleration amount when the second deceleration amount is equal to or less than a predetermined threshold value during vehicle driving in the automatic driving mode; and a stopping unit that stops the automatic driving mode when the second deceleration amount exceeds the predetermined threshold value.

FIELD

The present invention relates to a control device of a vehicle and a control method of a vehicle.

BACKGROUND

Conventionally, as described in Japanese Unexamined Patent Publication (Kokai) No. 2016-088180, it is known to stop automatic driving control when there is a driving operation by a driver in a traveling control device that performs automatic driving control.

SUMMARY

Technical Problem

Even when a vehicle travels by automatic driving, a driver is required to monitor a surrounding situation, and perform a crisis avoidance operation such as a brake operation in order to avoid a crisis when the crisis is recognized. However, according to the technique described in the patent literature described above, there is a problem that, when there is a driving operation by a driver, automatic driving control is stopped even in a case where the driver does not desire to stop automatic driving control. In this way, for a driver who does not desire to end automatic driving, the end of automatic driving by a driving operation causes a decrease in convenience.

In view of the problem described above, an object of the present disclosure is to provide a control device of a vehicle and a control method of a vehicle capable of optimally controlling deceleration of a vehicle, based on a deceleration amount when a vehicle is driven in an automatic driving mode and a deceleration amount according to an operation of a brake pedal by a driver.

Solution to Problem

A summary of the present disclosure is as follows.(1) A control device of a vehicle includes:a processor configured to:calculate a first deceleration amount for controlling deceleration of a vehicle during vehicle driving in an automatic driving mode;acquire a second deceleration amount of the vehicle according to an operation of a brake pedal when a driver operates the brake pedal;control deceleration of the vehicle by using a greater value of the first deceleration amount and the second deceleration amount when the second deceleration amount is equal to or less than a predetermined threshold value during vehicle driving in the automatic driving mode; andstop the automatic driving mode when the second deceleration amount exceeds the predetermined threshold value.(2) A control method of a vehicle includes:calculating a first deceleration amount for controlling deceleration of a vehicle during vehicle driving in an automatic driving mode;acquiring a second deceleration amount of the vehicle according to an operation of a brake pedal when a driver operates the brake pedal;controlling deceleration of the vehicle by using a greater value of the first deceleration amount and the second deceleration amount when the second deceleration amount is equal to or less than a predetermined threshold value during vehicle driving in the automatic driving mode; andstopping the automatic driving mode when the second deceleration amount exceeds the predetermined threshold value.

Advantageous Effects of Invention

The present disclosure provides a control device of a vehicle and a control method of a vehicle capable of optimally controlling deceleration of a vehicle, based on a deceleration amount when a vehicle is driven in an automatic driving mode and a deceleration amount according to an operation of a brake pedal by a driver.

DESCRIPTION OF EMBODIMENTS

Hereinafter, several embodiments according to the present invention will be described with reference to drawings. However, the description is intended to be merely an exemplification of a preferable embodiment of the present invention, and does not intend the present invention to be limited to such a specific embodiment. Note that, in the following description, the same reference sign is provided to a similar component.

FIG.1is a schematic diagram illustrating a configuration of a vehicle control system mounted on a vehicle100. The vehicle control system is applied to, for example, a system that enables traveling (hands-off traveling) while a driver drives a vehicle with no hands on a steering wheel. In the present embodiment, as such traveling, for example, traveling at approximately a level2or a level3or higher set by Society of Automotive Engineers (SAE) is assumed. Note that, hereinafter, traveling at the level is also referred to as automatic driving by a vehicle.

The vehicle control system includes a positioning information receiver110, a vehicle control apparatus120, a vehicle-mounted camera130, one or more sensors140, a navigation device150, an electronic control unit (ECU, hereinafter referred to as an ECU)160, a storage device170, and an input device180. Each of the positioning information receiver110, the vehicle control apparatus120, the vehicle-mounted camera130, the one or more sensors140, the navigation device150, the ECU160, the storage device170, and the input device180is communicably connected via an in-vehicle network conforming to a standard such as the Controller Area Network (CAN) and Ethernet (registered trademark).

The positioning information receiver110acquires positioning information indicating a current position and a posture of the vehicle100. For example, the positioning information receiver110can serve as a global positioning system (GPS) receiver. Every time the positioning information receiver110receives the positioning information, the positioning information receiver110outputs the acquired positioning information to the ECU160via the in-vehicle network.

The vehicle control apparatus120is various apparatuses involved in vehicle control, and includes an engine120aand a motor120bas a driving source that causes a vehicle to travel, a friction brake120c, a steering gear120d, a gearbox (not illustrated), and the like. Note that FIG.1illustrates a case where the vehicle is a plug-in hybrid vehicle (PHV), and the motor120bis not included in the vehicle control apparatus120when the vehicle is an engine vehicle. Further, when the vehicle is an electric vehicle (EV), the engine120ais not included in the vehicle control apparatus120.

The vehicle-mounted camera130includes a two-dimensional detector configured with an array of photoelectric conversion elements having sensitivity to visible light, such as a CCD or a C-MOS, and an imaging optical system that forms an image of a region to be captured on the two-dimensional detector. The vehicle-mounted camera130is provided near a dashboard, a front glass or the like in a vehicle, captures surroundings of the vehicle100for each predetermined capturing cycle (for example, 1/30 second to 1/10 second), and generates an image indicating the surroundings of the vehicle100. An image acquired by the vehicle-mounted camera130is preferably a color image. Further, the vehicle-mounted camera130may be formed of a stereo camera, and may be configured to acquire a distance from a parallax of left and right images to each structure on the image. Every time the vehicle-mounted camera130generates an image, the vehicle-mounted camera130outputs the generated image to the ECU160via the in-vehicle network.

The one or more sensors140include a brake sensor that detects a depression amount of a brake pedal by a driver, and the like.

The navigation device150obtains an intended traveling route from a current position of the vehicle100to a destination according to a predetermined route search technique such as a Dijkstra method.

The ECU160includes a processor162, a memory164, and a communication interface166. The processor162includes one or a plurality of central processing units (CPUs) and a peripheral circuit thereof. The processor162may further include another arithmetic circuit such as a logical arithmetic unit, a numerical arithmetic unit, or a graphic processing unit. The memory164includes, for example, a volatile semiconductor memory and a non-volatile semiconductor memory. The memory164stores various pieces of information about control according to the present embodiment. The communication interface166includes an interface circuit for connecting the ECU160to the in-vehicle network.

The storage device170includes, for example, a hard disk device or an optical recording medium and an access device thereof. The storage device170stores various pieces of information such as a high-definition map. Note that the storage device170may store a computer program for performing processing being performed on the processor162.

The input device180is a device to which operation information by a driver is input, and is formed of a button, a touch sensor, and the like. Setting for switching driving of the vehicle100to an automatic driving mode is input to the input device180by an operation of a driver. Further, information such as a destination is input to the input device180by an operation of a passenger. When setting for the automatic driving mode is input to the input device180, the vehicle100is set in the automatic driving mode and driven by automatic driving.

FIG.2is a schematic diagram illustrating a functional block of the processor162of the ECU160included in the vehicle100. The processor162is one aspect of a control device of a vehicle according to the present disclosure, and includes a deceleration amount calculation unit162a, a deceleration amount acquisition unit162b, a comparison unit162c, a deceleration control unit162d, a stopping unit162e, and a vehicle control unit162f. Each of the units included in the processor162is, for example, a functional module achieved by a computer program operating on the processor162. In other words, each of the units the processor162has is configured by the processor162and a program (software) for causing the processor162to function. Further, the program may be recorded in the memory164of the ECU160or a recording medium connected from the outside. Alternatively, each of the units the processor162has may be a dedicated arithmetic circuit provided in the processor162.

The deceleration amount calculation unit162aof the processor162calculates a first deceleration amount for controlling deceleration of the vehicle100during vehicle driving in the automatic driving mode. Note that the “deceleration amount” in the present embodiment is a value indicating a reduction amount of speed per unit time, and is an absolute value of negative acceleration. Specifically, the deceleration amount calculation unit162aapplies, to a high-precision map stored in the storage device170, position information indicating a current position of the vehicle100acquired by the positioning information receiver110, and calculates the first deceleration amount for controlling deceleration of the vehicle100in such a way that a distance from a structure such as a building, a guardrail, a wall, or a curb being present along a lane around the current position acquired from the high-precision map to the vehicle100does not fall below a predetermined distance threshold value, and a distance to an object (including the structure described above and another vehicle such as a preceding vehicle) around the vehicle100being recognized from an image generated by the vehicle-mounted camera130does not fall below the predetermined distance threshold value. Note that, for example, by template matching between a template image of an object and an image generated by the vehicle-mounted camera130or by an input of the image generated by the vehicle-mounted camera130to a discriminator subjected to machine learning for object detection, an object around the vehicle100is recognized from the image generated by the vehicle-mounted camera130.

Note that, as the discriminator described above, for example, a segmentation discriminator can be used. The segmentation discriminator is previously learned in such a way as to output, from an input image for each pixel of the image, a likelihood that an object having a probability of being indicated by the pixel is indicated by the pixel, for each kind of the object, and to identify that the object having a maximum likelihood is indicated. The deceleration amount calculation unit162acan use, as such a discriminator, a deep neural network (DNN) having an architecture of a segmentation convolutional neural network (CNN) such as a fully convolutional network (FCN), for example. Alternatively, the deceleration amount calculation unit162amay use a segmentation discriminator according to another machine learning technique, such as Random Forest or a support vector machine. In this case, the deceleration amount calculation unit162adetermines a pixel in which any object is captured in an image by inputting the image to the segmentation discriminator. Then, the deceleration amount calculation unit162asets a group of pixels in which an object of the same kind is captured as a region indicating the object.

The deceleration amount acquisition unit162bof the processor162acquires a second deceleration amount of the vehicle100according to an operation of a brake pedal when a driver operates the brake pedal during vehicle driving in the automatic driving mode. Specifically, the deceleration amount acquisition unit162bacquires the second deceleration amount, based on a detection value of a brake sensor that detects a depression amount of the brake pedal by the driver.

The comparison unit162cof the processor162compares the second deceleration amount and a predetermined threshold value. The predetermined threshold value is, for example, 0.1 G. The predetermined threshold value may be a different value according to a driving state such as a vehicle speed. Further, when the second deceleration amount is equal to or less than the predetermined threshold value, the comparison unit162ccompares the first deceleration amount and the second deceleration amount.

When the second deceleration amount is equal to or less than the predetermined threshold value, the deceleration control unit162dof the processor162controls deceleration of the vehicle100by using a greater value of the first deceleration amount and the second deceleration amount. In this way, even in a case where the second deceleration amount by the brake operation by the driver exceeds the first deceleration amount by system control of automatic driving, when the second deceleration amount is equal to or less than the predetermined threshold value, the vehicle100is decelerated by the second deceleration amount. Therefore, the automatic driving mode is not uniformly ended by the brake operation, and a crisis avoidance operation can be achieved by the operation of the brake pedal while driving of the vehicle100by the automatic driving mode continues, and convenience improves. Note that the deceleration control unit162dmay be included in the vehicle control unit162f.

When the second deceleration amount exceeds the predetermined threshold value, the stopping unit162eof the processor162stops the automatic driving mode. In this way, driving of the vehicle100is switched to manual driving by the driver, and the vehicle100is decelerated by the second deceleration amount according to the operation of the brake pedal by the driver.

When the vehicle100is set in the automatic driving mode, the vehicle control unit162fof the processor162controls the vehicle control apparatus120while referring to a high-precision map, and drives the vehicle100by automatic driving to a destination input to the input device180by the driver. The vehicle control unit162fdrives the vehicle100to the destination according to an intended traveling route to the destination being obtained by the navigation device150. Further, the vehicle control unit162fcontrols the vehicle control apparatus120, based on an object, a lane, display of a signal, and the like around the vehicle100being acquired from a high-precision map or an image generated by the vehicle-mounted camera130.

Next, processing performed by the processor162of the ECU160will be described based on a flowchart inFIG.3.FIG.3is the flowchart illustrating the processing performed by the processor162of the ECU160for each predetermined control cycle.

First, the processor162determines whether the vehicle100is set in an automatic driving mode (step S10). When the automatic driving mode is set, the deceleration amount calculation unit162aof the processor162calculates a first deceleration amount (step S12). On the other hand, when the automatic driving mode is not set, the processing in the present control cycle ends.

Next, the deceleration amount acquisition unit162bof the processor162acquires a second deceleration amount (step S14). Next, the comparison unit162cof the processor162compares the second deceleration amount and a predetermined threshold value, and when the second deceleration amount is equal to or less than the predetermined threshold value (YES in step S16), the comparison unit162ccompares the first deceleration amount and the second deceleration amount (step S18).

When the second deceleration amount is greater than the first deceleration amount (YES in step S18), the deceleration control unit162dof the processor162controls deceleration of the vehicle100by using the second deceleration amount (step S20).

On the other hand, when the second deceleration amount is equal to or less than the first deceleration amount (NO in step S18), the deceleration control unit162dof the processor162controls deceleration of the vehicle100by using the first deceleration amount (step S22).

Further, when the second deceleration amount is greater than the predetermined threshold value in step S16, the stopping unit162eof the processor162stops the automatic driving mode (step S24). After steps S20, S22, and S24, the processing in the present control cycle ends.

As described above, according to the present embodiment, by controlling deceleration of a vehicle by using a greater value of a first deceleration amount for controlling deceleration of the vehicle during vehicle driving in an automatic driving mode and a second deceleration amount according to an operation of a brake pedal by a driver, a crisis avoidance operation by the brake pedal can be achieved while traveling control by the automatic driving mode continues. Since traveling control by the automatic driving mode is not uniformly ended even when the second deceleration amount by the brake operation by the driver exceeds the first deceleration amount by system control of automatic driving, convenience improves.