Driving assistance device and driving assistance method

Abstract

The driving assistance device includes: a determination section (S140) that determines whether or not a brake light (92) of a preceding vehicle (90) located in front of a vehicle (80) is lit based on a lighting state of a headlight (91) of the preceding vehicle and an acceleration / deceleration of the preceding vehicle; a calculation section (S120, S150) that calculates a target acceleration / deceleration (Aacc, Ab) of the vehicle based on the determination of whether or not the brake light (92) of the preceding vehicle is lit by the determination section; and a control section (S200) that controls the vehicle to have an acceleration / deceleration of the vehicle corresponding to the target acceleration / deceleration.

Description

Technical Field

[0001] This disclosure relates to driving assistance devices and driving assistance programs. Background Technology

[0002] Previously, as described in Patent Document 1, there were known driving assistance devices that changed the target acceleration or deceleration of a vehicle based on the illumination state of the brake lights of the vehicle in front of it.

[0003] Patent Document 1: Japanese Patent Application Publication No. 2016-68684

[0004] According to the inventors' research, when the headlights of the vehicle in front are on, the taillights, which also function as brake lights, are also on. Therefore, some devices mistakenly interpret this as the brake lights of the vehicle in front being on, causing the vehicle to slow down. Consequently, there are instances where the vehicle slows down even though the vehicle in front is not actually slowing down. Therefore, there are situations where the vehicle cannot slow down appropriately. Summary of the Invention

[0005] The purpose of this disclosure is to provide a driving assistance device that enables a vehicle following another vehicle to slow down appropriately.

[0006] According to one aspect of this disclosure, a driving assistance device includes: a determination unit that determines whether the brake lights of a preceding vehicle are illuminated based on the illumination status of the headlights of the preceding vehicle located in front of the vehicle and the acceleration or deceleration of the preceding vehicle; a calculation unit that calculates a target acceleration or deceleration of the vehicle based on the determination unit's determination of whether the brake lights of the preceding vehicle are illuminated; and a control unit that controls the vehicle to achieve an acceleration or deceleration corresponding to the target acceleration or deceleration.

[0007] According to other aspects of this disclosure, the driving assistance device includes: a determination unit that determines whether the brake lights of the preceding vehicle are illuminated based on the illumination state of an auxiliary brake light located at a different position than a plurality of brake lights arranged in the width direction in the rear of the preceding vehicle, and which is illuminated according to the illumination of the brake lights of the preceding vehicle; a calculation unit that calculates the target acceleration or deceleration of the vehicle based on the determination unit's determination of whether the brake lights of the preceding vehicle are illuminated; and a control unit that controls the vehicle to achieve an acceleration or deceleration corresponding to the target acceleration or deceleration.

[0008] According to other aspects of this disclosure, the driving assistance program enables the driving assistance device to function as: a determination unit that determines whether the brake lights of the vehicle in front are illuminated based on the illumination status of the headlights of the vehicle in front of the vehicle and the acceleration or deceleration of the vehicle in front; a calculation unit that calculates the target acceleration or deceleration of the vehicle based on the determination unit's determination of whether the brake lights of the vehicle in front are illuminated; and a control unit that controls the vehicle to achieve the acceleration or deceleration of the vehicle corresponding to the target acceleration or deceleration.

[0009] According to other aspects of this disclosure, the driving assistance program enables the driving assistance device to function as: a determination unit that determines whether the brake lights of the preceding vehicle are illuminated based on the illumination status of an auxiliary brake light located at a different position than multiple brake lights arranged in the width direction in the rear of the preceding vehicle located in front of the vehicle, and which is illuminated according to the illumination of the brake lights of the preceding vehicle; a calculation unit that calculates the target acceleration / deceleration of the vehicle based on the determination unit's determination of whether the brake lights of the preceding vehicle are illuminated; and a control unit that controls the vehicle to achieve the acceleration / deceleration of the vehicle corresponding to the target acceleration / deceleration.

[0010] As a result, vehicles following the car in front can slow down appropriately.

[0011] Furthermore, the parenthesized reference numerals attached to each constituent element indicate an example of the correspondence between that constituent element and the specific constituent elements described in the embodiments described later. Attached Figure Description

[0012] Figure 1 This is a configuration diagram of an in-vehicle system using a driving assistance device implemented in this way.

[0013] Figure 2 This is a schematic diagram of the vehicle.

[0014] Figure 3 This is a diagram of the vehicle's braking system.

[0015] Figure 4 This is a flowchart illustrating the processing of driver assistance devices.

[0016] Figure 5 This is a diagram illustrating the situation where the brake lights of the vehicle in front are illuminated.

[0017] Figure 6 It is an image taken from the rear camera of the vehicle in front.

[0018] Figure 7 This is a diagram illustrating the situation where the brake lights of the vehicle in front are illuminated.

[0019] Figure 8 It is a graph showing the relationship between deceleration and time.

[0020] Figure 9 This is a camera image of a traffic light when the red light is on.

[0021] Figure 10 This is a camera image of a non-controlled vehicle when its brake lights are illuminated.

[0022] Figure 11 This is a schematic diagram illustrating brake precharge control. Detailed Implementation

[0023] Hereinafter, embodiments will be described with reference to the accompanying drawings. Furthermore, in each of the following embodiments, the same reference numerals will be used for the same or equivalent parts, and their descriptions will be omitted.

[0024] The driving assistance device 50 of this embodiment is applied to the vehicle system 1 of the vehicle 80 to assist in driving the vehicle 80. First, the vehicle system 1 will be described.

[0025] like Figure 1 As shown, the vehicle system 1 includes a peripheral monitoring sensor 10, a vehicle status sensor 20, an input operation unit 30, a vehicle-to-vehicle communication unit 40, a driver assistance device 50, an engine ECU 60, a brake ECU 65, and a braking system 70.

[0026] The surrounding monitoring sensor 10 outputs signals corresponding to the surrounding environment of the vehicle 80 to the driving assistance device 50, which will be described later. Specifically, the surrounding monitoring sensor 10 includes a sunlight sensor 11, an image sensor 12, and a detection wave transmitting and receiving unit 13.

[0027] The sunlight sensor 11 outputs a signal corresponding to the amount of sunlight Ms outside the vehicle 80 to the driver assistance device 50.

[0028] Image sensor 12 has a camera that captures images of the front, rear, and sides of vehicle 80. Furthermore, image sensor 12 outputs the captured camera images to driver assistance device 50, and based on the captured images, outputs information such as the types of obstacles surrounding vehicle 80 to driver assistance device 50.

[0029] The detection wave transmitting and receiving unit 13 transmits detection waves, such as millimeter waves, sonar, and infrared waves, to an object in front of the vehicle 80. Additionally, the detection wave transmitting and receiving unit 13 receives detection waves reflected by the object. Then, based on the information obtained from the detection waves, the detection wave transmitting and receiving unit 13 outputs signals to the driver assistance device 50 indicating the position, speed, and acceleration / deceleration of the object in front of the vehicle 80. Here, acceleration and deceleration refer to both acceleration and deceleration. Acceleration is the increase in speed per unit time, and deceleration is the decrease in speed per unit time. Furthermore, the direction of acceleration of the vehicle 80 is set as the positive direction.

[0030] The vehicle status sensor 20 outputs a signal corresponding to the driving status of the vehicle 80 to the driving assistance device 50. Specifically, the vehicle status sensor 20 includes a vehicle speed sensor 21 and an inertial sensor 22.

[0031] The vehicle speed sensor 21 outputs a signal corresponding to the speed of the vehicle 80 to the driving assistance device 50.

[0032] The inertial sensor 22 includes a gyroscope sensor and an accelerometer sensor, and outputs signals corresponding to the acceleration and deceleration of the vehicle 80 to the driving assistance device 50.

[0033] The input operation unit 30, operated by the driver of the vehicle 80, outputs signals indicating various operation settings to the driving assistance device 50. Specifically, the input operation unit 30 includes an ACC switch 31 and a headlight switch 32.

[0034] The ACC switch 31, through the on / off operation of the driver of vehicle 80, enables the execution of the program of the driving assistance device 50, described later. Furthermore, ACC stands for Adaptive Cruise Control.

[0035] The headlight switch 32 is operated by the driver of vehicle 80 to turn the lights on and off, such as... Figure 2 As shown, this illuminates the headlights of vehicle 80, i.e., the headlights 81 of this vehicle.

[0036] The vehicle-to-vehicle communication unit 40 communicates with other vehicles located around vehicle 80, receiving information such as accelerator operation status, brake operation status, headlight operation status, speed, and acceleration / deceleration from these other vehicles—in other words, other vehicle information. Then, as... Figure 1 As shown, the vehicle-to-vehicle communication unit 40 outputs the received information from other vehicles to the driving assistance device 50.

[0037] The driver assistance device 50 corresponds to the acquisition unit, determination unit, calculation unit, control unit, and pre-charge execution unit, and is mainly composed of a microcomputer, including a CPU, ROM, RAM, flash memory, I / O, and buses connecting these components. Furthermore, if the driver assistance device 50 executes a program stored in its ROM, it outputs command signals to the engine ECU 60 and brake ECU 65, which will be described later. These ROM, RAM, and flash memory are non-transferable physical storage media.

[0038] The engine ECU 60 is primarily composed of a microcomputer and includes a CPU, ROM, RAM, flash memory, I / O, and buses connecting these components. Furthermore, if the engine ECU 60 executes a program stored in its ROM, it controls the engine (not shown) of the vehicle 80 based on signals from the driver assistance device 50. These ROM, RAM, and flash memory components are non-transferable physical storage media.

[0039] The brake ECU 65 is primarily composed of a microcomputer and includes a CPU, ROM, RAM, flash memory, I / O, and buses connecting these components. Furthermore, when the brake ECU 65 executes a program stored in its ROM, it controls the braking system 70 of the vehicle 80 based on signals from the driver assistance device 50. These ROM, RAM, and flash memory are non-transferable physical storage media.

[0040] like Figure 3 As shown, the braking system 70 includes a brake pedal 71, a travel sensor 72, and a master cylinder 73. Additionally, the braking system 70 includes a set of pistons 74, two brake pads 75, brake calipers 76, and brake discs 77 at each wheel 82 of the vehicle 80.

[0041] The brake pedal 71 is depressed by the driver of vehicle 80. The travel sensor 72 detects the travel of the brake pedal 71. The master cylinder 73 generates hydraulic pressure upon depressing the brake pedal 71. This hydraulic pressure flows to the pistons 74 corresponding to each wheel 82. These pistons 74 hydraulically bring two brake pads 75 into contact with the brake disc 77. The two brake pads 75 are configured to clamp the brake disc 77. The brake caliper 76 supports the pistons 74 and the two brake pads 75. The brake disc 77 rotates together with the wheels 82. Therefore, in the braking system 70, when the brake pads 75 contact the brake disc 77 via the hydraulic pressure from the piston 74, the rotation of the brake disc 77 is slowed, thus slowing the rotation of the wheels 82 that rotate with the brake disc 77. As a result, vehicle 80 decelerates.

[0042] The vehicle system 1 is configured as described above. Here, through the processing of the driver assistance device 50 of the vehicle system 1, the vehicle 80 follows the vehicle 90 located in front of the vehicle 80.

[0043] Next, refer to Figure 4 The flowchart below explains the processing of the driver assistance device 50. Here, when the ACC switch 31 is turned on and a vehicle 90 is detected in front of the vehicle 80, the driver assistance device 50 executes a program stored in the ROM of the driver assistance device 50. Furthermore, for example, the detection of the vehicle 90 in front of the vehicle 80 is performed by detecting other vehicles within a specified range in front of the vehicle 80 using the surrounding monitoring sensor 10. Then, the information of the vehicle 90 detected by the surrounding monitoring sensor 10 is output to the driver assistance device 50.

[0044] In step S110, the driving assistance device 50 acquires various information from the surrounding monitoring sensor 10, the vehicle status sensor 20, the input operation unit 30, and the vehicle-to-vehicle communication unit 40. For example, the driving assistance device 50 acquires the vehicle-to-vehicle distance between the vehicle 80 and the preceding vehicle 90, as well as the speed and acceleration / deceleration of the preceding vehicle 90, from the detection wave transmitting and receiving unit 13. Additionally, the driving assistance device 50 acquires the speed of the vehicle 80 from the vehicle speed sensor 21. Furthermore, the driving assistance device 50 acquires the camera image captured by the image sensor 12. At this time, the driving assistance device 50 can also acquire the speed and acceleration / deceleration of the preceding vehicle 90 from the vehicle-to-vehicle communication unit 40.

[0045] Next, in step S120, the driving assistance device 50 calculates the acceleration / deceleration (ACC) target acceleration / deceleration Aacc to keep the inter-vehicle distance between vehicle 80 and the preceding vehicle 90 constant, as shown in equation (1-1). Here, in equation (1-1), Lp is the inter-vehicle distance between vehicle 80 and the preceding vehicle 90. Lt is the target inter-vehicle distance between vehicle 80 and the preceding vehicle 90, as shown in equation (1-2). Vf is the speed of the preceding vehicle 90. Vc is the speed of vehicle 80. K1 is the feedback gain for the error between the inter-vehicle distance and the target inter-vehicle distance, set through experiments or simulations. K2 is the feedback gain for the error of the relative speed of the preceding vehicle 90 relative to vehicle 80, set through experiments or simulations. Furthermore, in equation (1-2), h is set, for example, based on the time from when vehicle 80 is traveling at its current speed until it reaches the position of the preceding vehicle 90. Ls is a constant set through experiments or simulations.

[0046] [Number 1]

[0047] Aacc=K1×(Lp-Lt)+K2×(Vf-Vc)...(1-1)

[0048] Lt=h×Vc+Ls...(1-2)

[0049] Next, in step S130, the driving assistance device 50 determines whether there is a red light based on the camera image acquired in step S110 and the RGB values ​​of the brightness of the camera image. Here, "red light" refers to a red-colored light.

[0050] For example, the driver assistance device 50 scans a pre-defined pixel block on a camera image projected in front of the vehicle 80. In this case, if the average R component of the RGB values ​​of the brightness within the pixel block is above a threshold, the position of the red light on the camera image is determined, and the process proceeds to step S140. Alternatively, if the average R component of the RGB values ​​of the brightness within the pixel block is below the threshold, no red light is detected, and the process proceeds to step S200.

[0051] In step S140 following step S130, the driving assistance device 50 determines whether the brake light 92 of the preceding vehicle 90 is illuminated in the red light detected in step S130. Here, the driving assistance device 50 makes this determination based on the illumination status of the preceding vehicle 90's headlights 91, the acceleration / deceleration of the preceding vehicle 90, and the illumination status of the preceding vehicle 90's auxiliary brake light 93. Furthermore, the preceding vehicle brake light 92 also serves as the preceding vehicle 90's taillight.

[0052] Specifically, the driver assistance device 50 determines whether the headlight 91 of the vehicle in front is illuminated based on the time-varying brightness changes (i.e., brightness changes) of the image in front of the vehicle 80 acquired in step S110. Here, for example, when the vehicle 80 and the vehicle in front 90 enter a tunnel, or when the time period changes from daytime to nighttime, the brightness change of the background other than the vehicle in front 90 reflected in the image in front of the vehicle 80 exceeds a threshold. In this case, the driver assistance device 50 determines that the headlight 91 of the vehicle in front is illuminated. Furthermore, the threshold value for the brightness change related to the illumination of the headlight 91 is set through experiments or simulations.

[0053] Furthermore, when the headlights 91 of the vehicle in front are illuminated, the driver assistance device 50 determines whether the vehicle in front 90 is decelerating based on the acceleration and deceleration of the vehicle in front 90 obtained from the detector wave transmitting and receiving unit 13 in step S110. For example, the driver assistance device 50 determines that the vehicle in front 90 is decelerating when the acceleration and deceleration of the vehicle in front 90 is negative. Conversely, the driver assistance device 50 determines that the vehicle in front 90 is traveling at a constant speed when the acceleration and deceleration of the vehicle in front 90 is zero. And, the driver assistance device 50 determines that the vehicle in front 90 is accelerating when the acceleration and deceleration of the vehicle in front 90 is positive.

[0054] Moreover, such as Figure 5 As shown, when the headlights 91 of the vehicle in front are illuminated and the vehicle in front 90 decelerates, the driver assistance device 50 determines that the brake lights 92 of the vehicle in front are illuminated. Furthermore, in Figure 5 In the image, an arrow symbolically indicates that the vehicle in front is decelerating by 90 degrees.

[0055] Furthermore, the driver assistance device 50 determines that the front vehicle's brake lights 92 are not illuminated when the front vehicle's headlights 91 are illuminated but the front vehicle 90 is either moving at a constant speed or accelerating. Also, if the brightness change of the background other than the front vehicle 90 reflected in the image in front of the vehicle 80 is less than a threshold, the driver assistance device 50 determines that the front vehicle's headlights 91 are not illuminated. Moreover, when the front vehicle's headlights 91 are not illuminated, the driver assistance device 50 determines whether the front vehicle's brake lights 92 are illuminated based on the illumination status of the front vehicle's auxiliary brake lights 93. Furthermore, even when no acceleration or deceleration of the front vehicle 90 is detected, the driver assistance device 50 determines whether the front vehicle's brake lights 92 are illuminated based on the illumination status of the front vehicle's auxiliary brake lights 93.

[0056] Here, as Figure 6 As shown, two front brake lights 92 are arranged side-by-side in the width direction at the rear of the front vehicle 90. Additionally, the auxiliary brake light 93 of the front vehicle 90 is located at a different position than the front brake lights 92 at the rear of the front vehicle 90, for example, in the upper center of the rear of the front vehicle 90. Furthermore, the auxiliary brake light 93 of the front vehicle 90 is illuminated based on the illumination of the front brake lights 92, regardless of the illumination status of the front headlights 91.

[0057] Therefore, the driving assistance device 50 determines the illumination state of the auxiliary brake light 93 of the preceding vehicle 90 based on the brightness of the rear portion of the preceding vehicle 90 as reflected in the image acquired in step S110. Specifically, the driving assistance device 50 compares the brightness of the auxiliary brake light 93 of the preceding vehicle 90 with the brightness difference around the auxiliary brake light 93. For example, when the difference between the brightness of the auxiliary brake light 93 of the preceding vehicle 90 and the brightness of the center of the rear portion of the preceding vehicle 90 is above a threshold, the auxiliary brake light 93 of the preceding vehicle 90 is illuminated. Figure 7 The driving assistance device 50 determines that the front vehicle's brake light 92 is illuminated. Furthermore, when the difference between the brightness of the auxiliary brake light 93 of the front vehicle 90 and the brightness of the center of the rear of the front vehicle 90 is less than a threshold, the auxiliary brake light 93 of the front vehicle 90 is not illuminated, so the driving assistance device 50 determines that the front vehicle's brake light 92 is not illuminated. In addition, a brightness threshold related to the illumination state of the auxiliary brake light 93 of the front vehicle 90 is set through experiments or simulations.

[0058] In this way, the driver assistance device 50 determines whether the brake light 92 of the preceding vehicle is illuminated. If the brake light 92 is illuminated, the process moves to step S150. If the brake light 92 is not illuminated, the process moves to step S160.

[0059] In step S150 following step S140, the driver assistance device 50 calculates the deceleration that will cause the vehicle 80 to decelerate significantly greater than the target acceleration / deceleration Aacc used by ACC, i.e., the target braking deceleration Ab. For example, as Figure 8 As shown, the absolute value of the target deceleration Ab for braking is set to be greater than the absolute value of the deceleration in the target acceleration / deceleration Aacc for ACC. Furthermore, here, the change in vehicle 80's deceleration over the time when its deceleration is the target deceleration Ab for braking is greater than the change in vehicle 80's deceleration over the time when its deceleration is the target acceleration / deceleration Aacc for ACC. Thereafter, the process proceeds to step S200. Furthermore, Figure 8 The vertical axis represents the absolute value of the vehicle's deceleration at 80. Additionally, in Figure 8 In the diagram, solid lines represent the change in deceleration relative to time when the deceleration of vehicle 80 is the target deceleration Ab for braking. Dashed lines represent the change in deceleration relative to time when the deceleration of vehicle 80 is the target acceleration / deceleration Aacc for ACC.

[0060] In step S160 following step S140, the driver assistance device 50 determines whether the red light detected in step S130 is the red light of traffic light 5. For example, the driver assistance device 50 detects whether the red light reflected in the camera image is the red light of traffic light 5 by comparing a pre-set template image of traffic light 5 with the object of the red light reflected in the camera image of image sensor 12. Figure 9 As shown, when the red light reflected in the camera image is the red light of signal light 5, the process moves to step S170.

[0061] Furthermore, if the driver assistance device 50 does not detect the traffic light 5 reflected in the camera image, it determines that the red light detected in step S130 is not the red light of traffic light 5. Subsequently, the driver assistance device 50 determines whether the red light detected in step S130 is the brake light 7 of a non-controlled vehicle 6. Here, non-controlled vehicle 6 refers to vehicles other than vehicle 80 and the preceding vehicle 90.

[0062] For example, the driver assistance device 50 compares a pre-set template image of a non-controlled vehicle 6 with a red light object by excluding the preceding vehicle 90 reflected in the camera image of the image sensor 12, and thus detects whether the red light reflected in the camera image is the brake light 7 of the non-controlled vehicle 6. Furthermore, as... Figure 10As shown, when the red light displayed in the camera image is the brake light 7 of a non-controlled vehicle 6, the process moves to step S170. Alternatively, if the driver assistance device 50 does not detect a non-controlled vehicle 6 displayed in the camera image, it determines that the red light detected in step S130 is not the brake light 7 of a non-controlled vehicle 6. Thereafter, the process moves to step S200. Furthermore, as described above, the driver assistance device 50 determines whether the light is the brake light 7 of a non-controlled vehicle 6 after determining whether it is the red light of the traffic light 5. In contrast, the driver assistance device 50 may also determine whether the light is the red light of the traffic light 5 after determining whether it is the brake light 7 of a non-controlled vehicle 6.

[0063] In step S170 following step S160, since the red light of traffic light 5 is illuminated or the brake light 7 of the uncontrolled vehicle 6 is illuminated, the driver assistance device 50 determines whether the probability of collision between the vehicle 80 and obstacles such as the preceding vehicle 90, traffic light 5, and uncontrolled vehicle 6 is high. Specifically, the driver assistance device 50 determines whether the speed of vehicle 80, i.e., Vc, is greater than the speed threshold Vc_th. If the speed of vehicle 80, i.e., Vc, is greater than the speed threshold Vc_th, the process moves to step S180. Conversely, if the vehicle speed Vc is below the speed threshold Vc_th, the process moves to step S200. Furthermore, the speed threshold Vc_th is set through experiments or simulations.

[0064] In step S180, following step S170, the driving assistance device 50 determines whether the time-to-collision (TTC) between the vehicle 80 and each obstacle is less than a time threshold TTC_th in order to determine whether the probability of collision between the vehicle 80 and each obstacle is high. Specifically, the driving assistance device 50 calculates the relative distance between the vehicle 80 and each obstacle. Additionally, the driving assistance device 50 calculates the relative velocity of each obstacle relative to the vehicle 80, corresponding to the direction of each relative distance. Then, for each obstacle, the driving assistance device 50 calculates the TTC between the vehicle 80 and each obstacle by dividing the calculated relative distance by the corresponding relative velocity. If the TTC is less than the time threshold TTC_th, the process proceeds to step S190. If the TTC is greater than or equal to the time threshold TTC_th, the process proceeds to step S200. Furthermore, TTC stands for Time to Collision. The time threshold TTC_th is set through experiments or simulations.

[0065] In step S190 following step S180, since the speed of vehicle 80, i.e., Vc, is relatively high, and the TTC between vehicle 80 and each obstacle is relatively short, the probability of vehicle 80 colliding with each obstacle is relatively high. Therefore, the driving assistance device 50 performs brake precharge control. Specifically, the driving assistance device 50 outputs a command signal for this control to the brake ECU 65. The brake ECU 65 controls the braking system 70 of vehicle 80 based on the signal from the driving assistance device 50. For example, by controlling the electric pump (not shown) of the braking system 70, the hydraulic pressure of the piston 74 of the braking system 70 rises. As a result, the two brake pads 75 approach the brake disc 77 respectively. Therefore, the gap between the brake pads 75 and the brake disc 77 decreases. Here, the distance from the brake pads 75 to the brake disc 77 in the direction of contact between the brake pads 75 and the brake disc 77 is set as D. At this time, as Figure 11 As shown, the distance D from the brake pad 75 to the brake disc 77 is smaller compared to when the red light of the signal light 5 is not illuminated, and when the brake light 7 of the non-controlled vehicle 6 is not illuminated. Therefore, at this time, the deceleration responsiveness of vehicle 80 is improved, so vehicle 80 is less likely to collide with obstacles. The process then proceeds to step S200.

[0066] In step S200, the driving assistance device 50 assists the driving of the vehicle 80 by using the acceleration and deceleration of the vehicle 80 as the target acceleration and deceleration.

[0067] Specifically, when the driver assistance device 50 does not calculate the target deceleration Ab for braking in step S150, the acceleration and deceleration of the vehicle 80 becomes the target acceleration and deceleration Aacc for ACC. In this case, for example, if the acceleration and deceleration of the vehicle 80 is less than the target acceleration and deceleration Aacc for ACC, the driver assistance device 50 outputs a command signal for assistance to the engine ECU 60. At this time, the engine ECU 60 increases the speed of the engine (not shown) of the vehicle 80, so that the acceleration and deceleration of the vehicle 80 becomes the target acceleration and deceleration Aacc for ACC. Alternatively, for example, if the acceleration and deceleration of the vehicle 80 is greater than the target acceleration and deceleration Aacc for ACC, the driver assistance device 50 outputs a command signal for assistance to the brake ECU 65. At this time, the brake ECU 65 increases the hydraulic pressure of the piston 74 of the brake system 70, so that the brake pads 75 make frictional contact with the brake disc 77. As a result, together with the brake disc 77, the rotation of the wheel 82 is decelerated, so the vehicle 80 decelerates. Therefore, the acceleration and deceleration of the vehicle 80 becomes the target acceleration and deceleration Aacc for ACC.

[0068] Therefore, the acceleration and deceleration of vehicle 80 become the target acceleration and deceleration Aacc used by ACC to maintain the distance between vehicle 80 and the vehicle in front 90. Thus, vehicle 80 follows vehicle 90.

[0069] Furthermore, when the driver assistance device 50 calculates the target deceleration Ab for braking in step S150, it sets the acceleration and deceleration of the vehicle 80 to the target deceleration Ab for braking. In this case, for example, as described above, the brake ECU 65 causes the piston 74 of the braking system 70 to rise hydraulically, thereby causing the brake pads 75 to make frictional contact with the brake disc 77. As a result, the vehicle 80 decelerates, so the acceleration and deceleration of the vehicle 80 becomes the target deceleration Ab for braking.

[0070] Therefore, the acceleration and deceleration of vehicle 80 becomes the target deceleration Ab for braking, thereby maintaining the distance between vehicle 80 and the vehicle in front 90. Thus, vehicle 80 follows vehicle 90. Furthermore, here, the acceleration and deceleration of vehicle 80 becomes the deceleration that significantly reduces vehicle 80 compared to the target acceleration / deceleration Aacc for ACC, i.e., the target deceleration Ab for braking. Therefore, vehicle 80 can quickly respond to the deceleration of vehicle 90 in front, thus following vehicle 90 more safely.

[0071] As described above, by processing the driving assistance device 50, vehicle 80 follows the vehicle in front 90.

[0072] Next, we will explain the situation where the vehicle 80 following the vehicle 90 can appropriately slow down by means of the driving assistance device 50.

[0073] The driver assistance device 50 determines whether the brake lights 92 of the vehicle in front are illuminated based on the illumination status of the headlights 91 of the vehicle in front and the acceleration or deceleration of the vehicle in front 90. Specifically, as... Figure 5 As shown, when the headlight 91 of the vehicle in front is illuminated and the vehicle 90 in front is decelerating, the driving assistance device 50 determines that the brake light 92 of the vehicle in front is illuminated. Therefore, even if the taillight, which is also used as the brake light 92 of the vehicle in front, is illuminated, the vehicle 80 following the vehicle 90 can decelerate in advance, and thus decelerate appropriately.

[0074] Furthermore, the driver assistance device 50 determines whether the front vehicle's brake lights 92 are illuminated based on the illumination status of the auxiliary brake lights 93, which are located in a different position than the front vehicle's brake lights 92. Specifically, as... Figure 7 As shown, when the driver assistance device 50 determines that the auxiliary brake light 93 of the preceding vehicle 90 is illuminated, it determines that the brake light 92 of the preceding vehicle is illuminated. Therefore, similar to the above, even if the taillight, which also serves as the brake light 92 of the preceding vehicle, is illuminated, the vehicle 80 following the preceding vehicle 90 can appropriately decelerate.

[0075] In addition, the driver assistance device 50 also has the effects described below.

[0076] like Figure 9 as well as Figure 10Assume that the traffic light 5 is red or the brake light 7 of the uncontrolled vehicle 6 is illuminated, and the speed of vehicle 80, i.e., Vc, is greater than the speed threshold Vc_th, and the time threshold TTC is less than the time threshold TTC_th. At this time, the driver assistance device 50 performs brake pre-charge control. Therefore, compared to when the traffic light 5 is not red and the brake light 7 of the uncontrolled vehicle 6 is not illuminated, the gap between the brake pads 75 and the brake disc 77 is smaller. Specifically, as... Figure 11 As shown, the distance D from the brake pad 75 to the brake disc 77 is smaller compared to when the red light of the signal light 5 is not illuminated, and when the brake light 7 of the non-controlled vehicle 6 is not illuminated. Therefore, the deceleration responsiveness of the vehicle 80 is improved, thus suppressing collisions between the vehicle 80 and obstacles.

[0077] (Variation 1-1)

[0078] In the above embodiment, the driving assistance device 50 determines whether the headlights 91 of the vehicle in front are illuminated based on the brightness changes of the image in front of the vehicle 80 obtained from the image sensor 12. However, this determination is not limited to brightness changes based on the image in front of the vehicle 80. For example, the driving assistance device 50 can also determine whether the headlights 91 of the vehicle in front are illuminated based on the amount of sunlight Ms from outside the vehicle 80. Specifically, in step S110, in addition to the above information, the driving assistance device 50 also obtains the amount of sunlight Ms from outside the vehicle 80 from the sunlight sensor 11. Here, it is assumed that the amount of sunlight Ms obtained by the driving assistance device 50 is above the sunlight threshold Ms_th, for example, during daytime. In this case, since the surrounding environment is not conducive to illuminating the headlights, the driving assistance device 50 determines in step S140 that the headlights 91 of the vehicle in front are not illuminated. Additionally, suppose the solar irradiance Ms obtained by the driving assistance device 50 is less than the solar irradiance threshold Ms_th, for example, when vehicle 80 and the preceding vehicle 90 enter a tunnel or during nighttime. In this case, since the surrounding environment is such that headlights are on, the driving assistance device 50 determines in step S140 that the preceding vehicle's headlights 91 are on.

[0079] (Variations 1-2)

[0080] Additionally, the driver assistance device 50 can also determine whether the headlights 91 of the vehicle ahead are illuminated based on the illumination status of the vehicle's own headlights 81, specifically by determining whether the headlight switch 32 is on or off. Specifically, when the headlight switch 32 is on, the vehicle's own headlights 81 are illuminated, so it is assumed that the headlights 91 of the vehicle ahead are also illuminated in the same way. Therefore, the driver assistance device 50 determines that the headlights 91 of the vehicle ahead are illuminated when the headlight switch 32 is on. Conversely, when the headlight switch 32 is off, the vehicle's own headlights 81 are not illuminated, so it is assumed that the headlights 91 of the vehicle ahead are also off in the same way. Therefore, the driver assistance device 50 determines that the headlights 91 of the vehicle ahead are not illuminated when the headlight switch 32 is off.

[0081] (Variations 1-3)

[0082] Additionally, the driver assistance device 50 can also determine whether the headlight 91 of the preceding vehicle is illuminated based on whether the headlight switch of the preceding vehicle 90 is on or off. Specifically, the vehicle-to-vehicle communication unit 40 obtains the on / off status of the headlight switch of the preceding vehicle 90 by communicating with the preceding vehicle 90. Furthermore, in step S110, in addition to the above information, the driver assistance device 50 also obtains the on / off status of the headlight switch of the preceding vehicle 90 from the vehicle-to-vehicle communication unit 40. Moreover, when the headlight switch of the preceding vehicle 90 is on, the driver assistance device 50 determines in step S140 that the brake light 92 of the preceding vehicle is illuminated. Conversely, when the headlight switch of the preceding vehicle 90 is off, the driver assistance device 50 determines that the brake light 92 of the preceding vehicle is not illuminated.

[0083] In addition, the driver assistance device 50 can also determine whether the headlights 91 of the vehicle in front are lit based on the brightness changes of the image in front of the vehicle 80, the amount of sunlight Ms from outside the vehicle 80, the illumination status of the headlights 81 of the vehicle itself, and the combination of the on and off states of the headlights in the vehicle in front 90.

[0084] (Variation Example 2-1)

[0085] In the above embodiment, the driving assistance device 50 determines whether the front vehicle brake light 92 is illuminated based on the illumination status of the front vehicle's headlight 91, the acceleration / deceleration of the front vehicle 90, and the illumination status of the front vehicle 90's auxiliary brake light 93. The driving assistance device 50 is not limited to determining whether the front vehicle brake light 92 is illuminated based on this combination. For example, the driving assistance device 50 may also determine whether the front vehicle brake light 92 is illuminated based on the brightness changes at the left and right ends of the rear of the front vehicle 90 in the camera image acquired in step S110. Specifically, the driving assistance device 50 determines whether the front vehicle brake light 92 is illuminated based on the brightness changes from its normal state when the front vehicle brake light 92 is not illuminated.

[0086] Here, the brightness of the taillights in the front brake light 92 when illuminated is less than the brightness of the front brake light 92 when illuminated due to braking operation of the front vehicle 90. Therefore, when the change in brightness at the left and right ends of the rear of the front vehicle 90 from the normal state is greater than or equal to a first threshold and less than a second threshold, it can be estimated that the taillights in the front brake light 92 are illuminated. Therefore, at this time, the driver assistance device 50 determines that the front brake light 92 is not illuminated. Conversely, when the change in brightness at the left and right ends of the rear of the front vehicle 90 from the normal state is greater than or equal to a second threshold, it can be estimated that the front brake light 92 is illuminated due to braking operation of the front vehicle 90. Therefore, at this time, the driver assistance device 50 determines that the front brake light 92 is illuminated. Furthermore, the first and second thresholds are set through experiments or simulations.

[0087] (Variation Example 2-2)

[0088] Alternatively, for example, the driver assistance device 50 can determine whether the brake light 92 of the preceding vehicle is illuminated based on the collision margin time (ETTC) taking into account acceleration and deceleration. Specifically, in step S140, the driver assistance device 50 calculates the collision margin time (ETTC) taking into account acceleration and deceleration as shown in the following equation (2). In addition, ETTC stands for Enhanced Time to Collision. In addition, in equation (2), Vf is the speed of the preceding vehicle 90 as described above. Vc is the speed of the vehicle 80 as described above. Af is the acceleration and deceleration of the preceding vehicle 90. Ac is the acceleration and deceleration of the vehicle 80 as described above. Lp is the inter-vehicle distance between the vehicle 80 and the preceding vehicle 90 as described above.

[0089] [Number 2]

[0090]

[0091] Furthermore, in step S140, the driver assistance device 50 determines that the front vehicle's brake lights 92 are illuminated when the collision margin time ETTC decreases compared to the previously calculated collision margin time ETTC. Additionally, in step S150 following step S140, the driver assistance device 50 can also calculate the target deceleration Ab for braking based on the collision margin time ETTC that takes acceleration and deceleration into account. For example, the driver assistance device 50 calculates the target deceleration Ab for braking in such a way that as the collision margin time ETTC that takes acceleration and deceleration into account shortens, the absolute value of the target deceleration Ab for braking increases, in this case, the deceleration of vehicle 80 increases. Furthermore, the driver assistance device 50 determines that the front vehicle's brake lights 92 are not illuminated when the collision margin time ETTC remains unchanged compared to the previously calculated collision margin time ETTC. Conversely, the driver assistance device 50 determines that the front vehicle's brake lights 92 are not illuminated when the collision margin time ETTC increases compared to the previously calculated collision margin time ETTC.

[0092] (Variations 2-3)

[0093] Alternatively, for example, the driver assistance device 50 can also determine whether the brake light 92 of the preceding vehicle 90 is illuminated based on the brake operation status of the preceding vehicle 90. Specifically, the vehicle-to-vehicle communication unit 40 obtains the brake operation status of the preceding vehicle 90 through vehicle-to-vehicle communication. In addition, in step S110, the driver assistance device 50 obtains the brake operation status of the preceding vehicle 90 from the vehicle-to-vehicle communication unit 40, in addition to the above information. Moreover, when the brake pedal of the preceding vehicle 90 is pressed, the driver assistance device 50 determines in step S140 that the brake light 92 of the preceding vehicle is illuminated. Conversely, when the brake pedal of the preceding vehicle 90 is not pressed, the driver assistance device 50 determines that the brake light 92 of the preceding vehicle is not illuminated.

[0094] In addition, the driving assistance device 50 can also make the above determination based on a combination of the illumination status of the headlight 91 of the vehicle in front, the acceleration and deceleration of the vehicle in front, the illumination status of the auxiliary brake light 93 of the vehicle in front, the collision margin time (ETTC) taking into account acceleration and deceleration, and the brake operation status of the vehicle in front.

[0095] (Other implementation methods)

[0096] This disclosure is not limited to the above-described embodiments, and appropriate modifications can be made to the above-described embodiments. In addition, in each of the above embodiments, except for elements that are specifically stated to be necessary or elements that are clearly considered to be necessary in principle, the elements constituting the embodiments are not necessarily necessary elements.

[0097] The control unit and methods described herein may also be implemented by a dedicated computer consisting of a processor and memory programmed to perform one or more functions embodied in a computer program. Alternatively, the control unit and methods described herein may be implemented by a dedicated computer consisting of a processor composed of one or more dedicated hardware logic circuits. Alternatively, the control unit and methods described herein may be implemented by one or more dedicated computers consisting of a combination of a processor programmed to perform one or more functions and a memory, and a processor composed of one or more hardware logic circuits. Furthermore, the computer program may also be stored as instructions executable by a computer on a non-transferable tangible recording medium readable by a computer.

[0098] (1) In the above embodiment, the driving assistance device 50 determines whether the front vehicle brake light 92 is illuminated based on a combination of the illumination status of the front vehicle's headlight 91, the acceleration / deceleration of the front vehicle 90, and the illumination status of the front vehicle's auxiliary brake light 93. Alternatively, the driving assistance device 50 may determine whether the front vehicle brake light 92 is illuminated based solely on the illumination status of the front vehicle's headlight 91 and the acceleration / deceleration of the front vehicle 90. Furthermore, the driving assistance device 50 may also determine whether the front vehicle brake light 92 is illuminated based solely on the illumination status of the front vehicle's auxiliary brake light 93.

[0099] (2) In the above embodiment, the driving assistance device 50 calculates the target acceleration / deceleration Aacc for ACC based on K1, Lp, Lt, K2, Vf, and Vc in the above-described equation (1-1). Furthermore, as described above, Lp is the inter-vehicle distance between vehicle 80 and the preceding vehicle 90. Lt is the target inter-vehicle distance between vehicle 80 and the preceding vehicle 90, as shown in the above-described equation (1-2). Vf is the speed of the preceding vehicle 90. Vc is the speed of vehicle 80. K1 is the feedback gain for the error between the inter-vehicle distance and the target inter-vehicle distance. K2 is the feedback gain for the error of the relative speed of the preceding vehicle 90 relative to vehicle 80. H is the time from when vehicle 80 is traveling at its current speed until it reaches the position of the preceding vehicle 90. Ls is a constant set through experiments or simulations.

[0100] In contrast, the driver assistance device 50 is not limited to calculating the target acceleration / deceleration Aacc for ACC based on K1, Lp, Lt, K2, Vf, and Vc of the aforementioned relationship (1-1). For example, the driver assistance device 50 may also calculate the target acceleration / deceleration Aacc for ACC based on the collision time ETTC, which takes into account acceleration and deceleration. Specifically, the driver assistance device 50 may also calculate the target acceleration / deceleration Aacc for ACC in a manner where the deceleration in the target acceleration / deceleration Aacc increases when the collision time ETTC, which takes into account acceleration and deceleration, decreases, for example, when vehicle 80 approaches the vehicle in front 90. Furthermore, the driver assistance device 50 may calculate the target acceleration / deceleration Aacc for ACC in a manner where the acceleration in the target acceleration / deceleration Aacc increases when the collision time ETTC, which takes into account acceleration and deceleration, increases, for example, when vehicle 80 moves away from the vehicle in front 90.

[0101] (3) In the above embodiments, vehicle 80 has an internal combustion engine. However, it is not limited to vehicle 80 having an internal combustion engine. For example, vehicle 80 may also be an electric vehicle, a hybrid electric vehicle, or a fuel cell vehicle.

[0102] (4) In the above embodiment, the driving assistance device 50 determines whether the headlight 91 of the preceding vehicle is illuminated based on the time change, i.e., brightness change, of the image in front of the vehicle 80 acquired in step S110. However, this determination is not limited to brightness change. For example, the driving assistance device 50 may also determine whether the headlight 91 of the preceding vehicle is illuminated based on the brightness and brightness gradient of the image in front of the vehicle 80 acquired in step S110. Furthermore, in the above embodiment, the driving assistance device 50 determines the illumination state of the auxiliary brake light 93 of the preceding vehicle 90 based on the brightness of the rear of the preceding vehicle 90 reflected in the image acquired in step S110. Again, this determination is not limited to brightness. For example, the driving assistance device 50 may also determine the illumination state of the auxiliary brake light 93 of the preceding vehicle 90 based on brightness change and brightness gradient.

Claims

1. A driving assistance device, wherein, have: The determination unit determines whether the brake light of the vehicle in front, which also serves as a taillight, is lit, based on the illumination status of the headlight of the vehicle in front of the vehicle and the acceleration or deceleration of the vehicle in front. The calculation unit calculates the target acceleration or deceleration of the vehicle based on whether the brake lights of the preceding vehicle are illuminated; and The control unit controls the vehicle to achieve acceleration and deceleration corresponding to the target acceleration and deceleration. The preceding vehicle also has an auxiliary brake light, which is located at a different position from the plurality of brake lights arranged along the width direction at the rear of the preceding vehicle, and is illuminated in response to the illumination of the aforementioned brake lights. When the reduction in brightness of the background other than the vehicle in front, as reflected in the image in front of the aforementioned vehicle, is greater than or equal to a threshold, the determination unit determines that the headlights of the vehicle in front are on. If the reduction is less than the threshold, it is determined that the headlights of the vehicle in front are not turned on. When the headlights of the vehicle in front are illuminated, thereby illuminating the taillights of the vehicle in front, and the difference between the brightness of the auxiliary brake lights of the vehicle in front and the brightness of the center of the rear of the vehicle in front is above a threshold, the auxiliary brake lights of the vehicle in front are illuminated, and therefore it is determined that the brake lights are illuminated.

2. A driving assistance device, wherein, have: The determination unit determines whether the brake light of the vehicle in front, which also serves as a taillight, is lit, based on the illumination status of the headlight of the vehicle in front of the vehicle and the acceleration or deceleration of the vehicle in front. The calculation unit calculates the target acceleration or deceleration of the vehicle based on whether the brake lights of the preceding vehicle are illuminated; and The control unit controls the vehicle to achieve an acceleration or deceleration rate corresponding to the target acceleration or deceleration rate. The aforementioned vehicle also features an auxiliary brake light, which is positioned at the rear of the vehicle in a different location from the plurality of brake lights arranged along the width direction, and illuminates in response to the illumination of the aforementioned brake lights. When the increase in brightness of the taillights of the preceding vehicle is greater than a first threshold but less than a second threshold, the aforementioned determination unit determines that the taillights of the preceding vehicle are illuminated, the brake lights of the preceding vehicle are not illuminated, and the headlights of the preceding vehicle are illuminated. When the increase is above the second threshold, it is determined that the brake lights of the preceding vehicle are illuminated. When the headlights of the preceding vehicle are illuminated, thereby illuminating the taillights of the preceding vehicle, and the difference between the brightness of the auxiliary brake lights of the preceding vehicle and the brightness of the center of the rear of the preceding vehicle is above the threshold, the auxiliary brake lights of the preceding vehicle are illuminated, and therefore it is determined that the brake lights are illuminated.

3. A driving assistance device, wherein, have: The determination unit determines whether the brake light of the vehicle in front, which also serves as a taillight, is lit, based on the illumination status of the headlight of the vehicle in front of the vehicle and the acceleration or deceleration of the vehicle in front. The calculation unit calculates the target acceleration or deceleration of the vehicle based on whether the brake lights of the preceding vehicle are illuminated; and The control unit controls the vehicle to achieve an acceleration or deceleration rate corresponding to the target acceleration or deceleration rate. The aforementioned vehicle also features an auxiliary brake light, which is positioned at the rear of the vehicle in a different location from the plurality of brake lights arranged along the width direction, and illuminates in response to the illumination of the aforementioned brake lights. When the amount of sunlight from outside the aforementioned vehicle exceeds the sunlight threshold, the aforementioned determination unit determines that the headlights of the vehicle in front are not turned on. When the solar irradiance is less than the solar irradiance threshold, it is determined that the headlights of the vehicle in front are lit. When the headlights of the vehicle in front are lit, and the taillights of the vehicle in front are lit, and the difference between the brightness of the auxiliary brake lights of the vehicle in front and the brightness of the center of the rear of the vehicle in front is above the threshold, the auxiliary brake lights of the vehicle in front are lit, and therefore it is determined that the brake lights are lit.

4. A driving assistance device, wherein, have: The determination unit determines whether the brake light of the vehicle in front, which also serves as a taillight, is lit, based on the illumination status of the headlight of the vehicle in front of the vehicle and the acceleration or deceleration of the vehicle in front. The calculation unit calculates the target acceleration or deceleration of the vehicle based on whether the brake lights of the preceding vehicle are illuminated; and The control unit controls the vehicle to achieve an acceleration or deceleration rate corresponding to the target acceleration or deceleration rate. The aforementioned vehicle also features an auxiliary brake light, which is positioned at the rear of the vehicle in a different location from the plurality of brake lights arranged along the width direction, and illuminates in response to the illumination of the aforementioned brake lights. When the headlights of the aforementioned vehicle are not illuminated, the aforementioned determination unit determines that the headlights of the vehicle in front are not illuminated. When the headlights of the aforementioned vehicle are illuminated, it is determined that the headlights of the preceding vehicle are illuminated. When the headlights of the preceding vehicle are illuminated, and the taillights of the preceding vehicle are illuminated, and the difference between the brightness of the auxiliary brake lights of the preceding vehicle and the brightness of the center of the rear of the preceding vehicle is above a threshold, the auxiliary brake lights of the preceding vehicle are illuminated, and therefore it is determined that the brake lights are illuminated.

5. The driving assistance device according to any one of claims 1 to 4, wherein, The aforementioned determination unit determines whether the brake lights of the vehicle in front are illuminated based on the collision margin between the aforementioned vehicle and the vehicle in front, which is determined by the acceleration and deceleration of the aforementioned vehicle and the vehicle in front.

6. The driving assistance device according to claim 5, wherein, The aforementioned calculation unit calculates the target acceleration / deceleration based on the collision margin between the aforementioned vehicle and the aforementioned preceding vehicle, which is based on the acceleration / deceleration of the aforementioned vehicle and the aforementioned preceding vehicle.

7. The driving assistance device according to any one of claims 1 to 4, wherein, It also has a unit for acquiring the brake operation status of the preceding vehicle via vehicle-to-vehicle communication. The aforementioned determination unit determines whether the brake lights of the preceding vehicle are illuminated based on the brake operation status of the preceding vehicle.

8. The driving assistance device according to claim 7, wherein, The aforementioned acquisition unit acquires the acceleration and deceleration of the preceding vehicle through the aforementioned vehicle-to-vehicle communication. The determination unit determines whether the brake lights of the preceding vehicle are illuminated based on the acceleration or deceleration of the preceding vehicle obtained by the acquisition unit.

9. The driving assistance device according to any one of claims 1 to 4, wherein, When the determination unit determines that the brake lights of the vehicle in front are illuminated, the aforementioned calculation unit calculates a target deceleration for braking. This target deceleration for braking is compared with the target acceleration / deceleration for ACC (Adaptive Cruise Control) that keeps the distance from the vehicle to the vehicle in front constant, causing the vehicle to decelerate more significantly. The aforementioned control unit controls the vehicle to achieve an acceleration or deceleration rate corresponding to the aforementioned target deceleration rate for braking.

10. The driving assistance device according to any one of claims 1 to 4, wherein, It also has a pre-charge actuator that, when the brake lights of a non-controlled vehicle different from the aforementioned vehicle and the aforementioned preceding vehicle are illuminated, makes the gap between the brake pads and brake discs of the aforementioned vehicle smaller than when the brake lights of the aforementioned non-controlled vehicle are not illuminated.

11. The driving assistance device according to claim 10, wherein, When the signal light in front of the vehicle is red, the pre-charge actuator makes the gap between the brake pads and the brake disc smaller than when the brake light of the non-controlled vehicle is not illuminated.

12. The driving assistance device according to claim 10, wherein, When the speed of the vehicle is greater than the speed threshold, the pre-charge actuator makes the gap between the brake pads and the brake disc smaller than when the brake lights of the uncontrolled vehicle are not illuminated.

13. The driving assistance device according to claim 10, wherein, When the collision margin between the vehicle and the object, based on the speed of the vehicle and the object different from the vehicle, is less than a time threshold, the pre-charge actuator makes the gap between the brake pads and the brake disc smaller than when the brake lights of the uncontrolled vehicle are not illuminated.

14. A driving assistance method, wherein, include: The determination step is to determine whether the brake lights of the vehicle in front, which also serves as taillights, are lit, based on the illumination status of the headlights of the vehicle in front and the acceleration or deceleration of the vehicle in front. The calculation steps are based on whether the brake lights of the vehicle in front are lit, to calculate the target acceleration and deceleration of the vehicle. as well as The control step involves controlling the vehicle to achieve an acceleration or deceleration rate corresponding to the target acceleration or deceleration rate. In the above determination step, when the reduction in brightness of the background other than the vehicle in front of the image is above a threshold, it is determined that the headlights of the vehicle in front are on. When the reduction is less than the threshold, it is determined that the headlights of the preceding vehicle are not illuminated. When the headlights of the preceding vehicle are illuminated, thereby illuminating the taillights of the preceding vehicle, and the difference between the brightness of the preceding vehicle's auxiliary brake lights and the brightness of the center of the rear of the preceding vehicle is above the threshold, the auxiliary brake lights of the preceding vehicle are illuminated, and therefore it is determined that the brake lights are illuminated. The aforementioned auxiliary brake light is located at a different position than the plurality of brake lights arranged along the width direction in the rear of the aforementioned vehicle, and is illuminated in response to the illumination of the aforementioned brake lights.

15. A driving assistance method, wherein, Driving assistance methods for driving assistance devices include: The determination step is to determine whether the brake lights of the vehicle in front, which also serves as taillights, are lit, based on the illumination status of the headlights of the vehicle in front and the acceleration or deceleration of the vehicle in front. The calculation steps involve calculating the target acceleration and deceleration of the vehicle mentioned above, based on whether the brake lights of the vehicle in front are illuminated; and The control step involves controlling the vehicle to achieve an acceleration or deceleration rate corresponding to the target acceleration or deceleration rate. In the above determination step, if the increase in brightness of the taillights of the preceding vehicle is above the first threshold and below the second threshold, it is determined that the taillights of the preceding vehicle are on, the brake lights of the preceding vehicle are off, and the headlights of the preceding vehicle are on. When the increase exceeds the second threshold, the brake lights of the vehicle ahead are determined to be illuminated. When the headlights of the preceding vehicle are illuminated, causing the taillights of the preceding vehicle to be illuminated, and the difference between the brightness of the preceding vehicle's auxiliary brake lights and the brightness of the center of the rear of the preceding vehicle is above a threshold, the auxiliary brake lights of the preceding vehicle are illuminated, and therefore it is determined that the brake lights are illuminated. The aforementioned auxiliary brake light is located at a different position than the plurality of brake lights arranged along the width direction in the rear of the aforementioned vehicle, and is illuminated in response to the illumination of the aforementioned brake lights.

16. A driving assistance method, wherein, The driving assistance method of the driving assistance device includes: a determination step, which determines whether the brake light of the vehicle in front, which also serves as a taillight, is lit based on the illumination status of the headlight of the vehicle in front of the vehicle and the acceleration or deceleration of the vehicle in front. The calculation steps involve calculating the target acceleration and deceleration of the vehicle mentioned above, based on whether the brake lights of the vehicle in front are illuminated; and The control step involves controlling the vehicle to achieve an acceleration or deceleration rate corresponding to the target acceleration or deceleration rate. In the above determination step, if the amount of sunlight from outside the vehicle is above the sunlight threshold, it is determined that the headlights of the vehicle in front are not turned on. When the aforementioned solar irradiance is less than the solar irradiance threshold, it is determined that the headlights of the aforementioned vehicle in front are turned on. When the headlights of the preceding vehicle are illuminated, causing the taillights of the preceding vehicle to be illuminated, and the difference between the brightness of the preceding vehicle's auxiliary brake lights and the brightness of the center of the rear of the preceding vehicle is above a threshold, the auxiliary brake lights of the preceding vehicle are illuminated, and therefore it is determined that the brake lights are illuminated. The aforementioned auxiliary brake light is located at a different position than the plurality of brake lights arranged along the width direction in the rear of the aforementioned vehicle, and is illuminated in response to the illumination of the aforementioned brake lights.

17. A driving assistance method, wherein, Driving assistance methods for driving assistance devices include: The determination step is to determine whether the brake lights of the vehicle in front, which also serves as taillights, are lit, based on the illumination status of the headlights of the vehicle in front and the acceleration or deceleration of the vehicle in front. The calculation steps involve calculating the target acceleration and deceleration of the vehicle mentioned above, based on whether the brake lights of the vehicle in front are illuminated; and The control step involves controlling the vehicle to achieve an acceleration or deceleration rate corresponding to the target acceleration or deceleration rate. In the above determination steps, if the headlights of the aforementioned vehicle are not illuminated, it is determined that the headlights of the vehicle in front are not illuminated. When the headlights of the aforementioned vehicles are illuminated, it is determined that the headlights of the vehicle in front are illuminated. When the headlights of the preceding vehicle are illuminated, causing the taillights of the preceding vehicle to be illuminated, and the difference between the brightness of the preceding vehicle's auxiliary brake lights and the brightness of the center of the rear of the preceding vehicle is above a threshold, the auxiliary brake lights of the preceding vehicle are illuminated, and therefore it is determined that the brake lights are illuminated. The aforementioned auxiliary brake light is located at a different position than the plurality of brake lights arranged along the width direction in the rear of the aforementioned vehicle, and is illuminated in response to the illumination of the aforementioned brake lights.

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