Driving support device

Abstract

A driving assistance device defines a first condition as the distance between itself and a preceding vehicle being less than a first threshold, a second condition as the speed of the preceding vehicle relative to itself being less than a second threshold, a third condition as the speed of an adjacent vehicle traveling in the adjacent lane being less than a third threshold, and a fourth condition as the acceleration of the adjacent vehicle being less than a fourth threshold. When at least one of the first and second conditions is met, and at least one of the third and fourth conditions is met, the driving assistance ECU 10 performs acceleration suppression control on one or both of the drive and braking devices in a manner that causes the acceleration of its own vehicle to be less than or equal to "0".

Description

Technical Field

[0001] The present invention relates to a driving support device for controlling the drive and braking devices of a vehicle in a manner that makes the inter-vehicle distance between the preceding vehicle and the vehicle consistent with a target value. Background Technology

[0002] Previously, driving support devices (hereinafter referred to as "conventional devices") that provide cruise control to assist in operating the accelerator and brake pedals of a vehicle have been proposed (see Japanese Patent Application Laid-Open No. 2012-153296 below). Specifically, conventional devices control the drive and braking systems of a vehicle in a manner that ensures the distance between the vehicle and a preceding vehicle matches a target value. For example, when a preceding vehicle repeatedly accelerates and decelerates (when the acceleration of the preceding vehicle frequently increases or decreases), the conventional device adjusts the speed of the vehicle in accordance with the speed changes of the preceding vehicle, thereby ensuring the distance between the vehicle and the preceding vehicle matches the target value. Summary of the Invention

[0003] In this case, conventional devices, during cruise control, will repeatedly accelerate and decelerate in response to a preceding vehicle's rapid acceleration and deceleration over a short period (within a short interval). For example, this repeated acceleration and deceleration is highly likely to occur when there is congestion in the lanes where both the preceding and preceding vehicles are traveling. When the vehicle's speed changes significantly within such a short period, the occupants of the vehicle may experience discomfort.

[0004] One of the objectives of this invention is to provide a driving support device that can reduce the discomfort of vehicle occupants by reducing the repeated acceleration and deceleration during traffic jams.

[0005] To solve the above-mentioned problems, the driving support device (1) of the present invention includes:

[0006] The drive unit (20) applies driving force to the drive wheels of its own vehicle;

[0007] Braking device (30) applies braking force to the drive wheel;

[0008] The surrounding sensor (50) outputs information related to objects around the vehicle, i.e., surrounding information; and

[0009] The driving support control device (10) performs the following following control: based on the surrounding information, it determines a target value for the inter-vehicle distance (L) between its own vehicle and a preceding vehicle traveling directly in front of it, and controls the drive device and the braking device in such a way that the measured value of the inter-vehicle distance obtained based on the surrounding information is consistent with the target value.

[0010] The case where the workshop distance is smaller than the first threshold (δ) is defined as the first condition (Z1).

[0011] The second condition (Z2) is defined as the situation where the speed of the preceding vehicle relative to itself is less than the second threshold (ε).

[0012] The third condition (Z3) is defined as the situation where the speed of a vehicle traveling in the adjacent lane is less than the third threshold (ζ).

[0013] The condition Z4 is defined as the case where the acceleration of the adjacent vehicle is less than the fourth threshold (η).

[0014] The driving support control device performs acceleration suppression control as follows: when at least one of the first condition and the second condition is met and at least one of the third condition and the fourth condition is met, it controls one or both of the drive device and the braking device in such a way that the acceleration of its own vehicle is less than "0".

[0015] The driving support control device of the present invention presumes that congestion has not been relieved when the first and / or second conditions are met and the third and / or fourth conditions are met. Furthermore, in this case, the driving support control device performs acceleration suppression control on the drive unit and / or braking unit in a manner that reduces the acceleration of the vehicle itself to "0" or less. That is, according to the present invention, in situations where the likelihood of preceding vehicles repeatedly accelerating and decelerating (during congestion), it is possible to suppress the repeated acceleration and deceleration of the vehicle following preceding vehicles. Therefore, compared to conventional devices (devices that do not have the function of presuming whether congestion has been relieved), it is possible to reduce the discomfort of the vehicle's occupants.

[0016] In one aspect of the driving support device of the present invention,

[0017] The condition is defined as the fifth condition (Y1) when the distance between the vehicle and the preceding vehicle is less than the fifth threshold (β) of the first threshold.

[0018] The condition is defined as the sixth condition (Y2) when the speed of the preceding vehicle relative to itself is less than the sixth threshold (γ), which is less than the second threshold.

[0019] The driving support control device

[0020] If conditions 5 and 6 are met, or

[0021] If one or both of the fifth and sixth conditions are not met, and at least one of the first and second conditions is met, and at least one of the third and fourth conditions is met,

[0022] Perform the acceleration suppression control.

[0023] Therefore, even if the preceding vehicle accelerates when the distance between vehicles and the relative speed are small, the vehicle itself will not accelerate. This reduces the likelihood of repeated acceleration and deceleration within the vehicle, thus minimizing discomfort for the occupants.

[0024] In another technical solution of the present invention, a driving support device,

[0025] The driving support control device performs the acceleration suppression control when the first to fourth conditions are met.

[0026] The driving support control device of this technical solution presumes that congestion has not been alleviated when conditions 1 and 2 are met, and conditions 3 and 4 are met. Furthermore, in this case, the driving support control device performs acceleration suppression control. This reduces the frequency of repeated acceleration and deceleration in the vehicle, thereby reducing discomfort for the vehicle's occupants.

[0027] In another technical solution of the present invention, a driving support device,

[0028] The driving support control device stops the execution of the acceleration suppression control when at least one of the first to fourth conditions no longer exists during the execution of the acceleration suppression control.

[0029] The driving support control device of this technical solution presumes the congestion has ended and stops executing acceleration suppression control when at least one of conditions 1 to 4 no longer exists during acceleration suppression control. That is, it puts the vehicle in a state where it can accelerate. Thus, it can prevent the vehicle from excessively increasing its inter-vehicle distance without accelerating.

[0030] In another technical solution of the present invention, a driving support device,

[0031] The driving support control device prohibits the execution of acceleration suppression control from the moment it stops executing the acceleration suppression control until the speed of its own vehicle exceeds a predetermined threshold.

[0032] Therefore, it is possible to suppress the frequent execution of acceleration suppression control. Attached Figure Description

[0033] The features, advantages, and technical and industrial importance of exemplary embodiments of the present invention will now be described with reference to the accompanying drawings, wherein like reference numerals denote like parts, and wherein:

[0034] Figure 1 This is a block diagram of a driving support device according to one embodiment of the present invention.

[0035] Figure 2 This is a flowchart of the acceleration suppression control start procedure.

[0036] Figure 3 It is a flowchart of the acceleration suppression control stop procedure. Detailed Implementation

[0037] (Outline of composition)

[0038] like Figure 1 As shown, a driving support device 1 according to one embodiment of the present invention is mounted on a vehicle V. Details of the driving support device 1 will be described below. Based on information obtained from sensors mounted on the vehicle V, it controls the engine, brakes, etc., of the vehicle V to maintain a constant speed or to follow a vehicle VF traveling directly in front of the vehicle V. Hereinafter, this control will be referred to as "cruise control." Furthermore, when predetermined conditions are met during the execution of cruise control, the driving support device 1 suppresses the acceleration of the vehicle V. Hereinafter, this control will be referred to as "acceleration suppression control." In the following description, the vehicle V will be referred to as "the vehicle itself," and the vehicle VF will be referred to as "the preceding vehicle."

[0039] (Specific composition)

[0040] like Figure 1 As shown, the driving support device 1 includes a driving support ECU 10, a drive unit 20, a braking unit 30, a gear shifting device 40, an ambient sensor 50, and an operation switch 60.

[0041] The driving support ECU 10 includes a microcomputer comprising a CPU 10a, RAM 10b, ROM 10c, etc. Furthermore, in this specification, "ECU" means Electronic Control Unit, which includes a microcomputer comprising a CPU, RAM, ROM, etc. The CPU performs various functions by executing instructions stored in the ROM.

[0042] The driving support ECU10 is connected to other ECUs (engine ECU21, brake ECU31 and SBW ECU41, described later) via CAN (Controller Area Network) in a manner that enables them to send and receive information.

[0043] The drive unit 20 generates driving force and applies it to the drive wheels (left front wheel, right front wheel, left rear wheel, and right rear wheel). The drive unit 20 includes an engine ECU 21, an engine actuator 22, an internal combustion engine 23, a transmission 24, and a drive force transmission mechanism (not shown) that transmits the driving force to the wheels. The engine ECU 21 is connected to the engine actuator 22. The engine actuator 22 includes a throttle actuator that changes the opening of the throttle valve of the internal combustion engine 23. The engine ECU 21 can change the torque generated by the internal combustion engine 23 by driving the engine actuator 22. The torque generated by the internal combustion engine 23 is transmitted to the drive wheels via the transmission 24 and the drive force transmission mechanism (e.g., a drive shaft). As described above, the engine ECU 21 controls the driving force of the vehicle V by controlling the engine actuator 22.

[0044] Furthermore, when the vehicle V using the driving assistance device 1 is a hybrid electric vehicle (PHEV, HEV), the engine ECU 21 can control the driving force generated by either or both of the "internal combustion engine and electric motor" that serve as the vehicle's drive source. Additionally, when the vehicle V using the driving assistance device 1 is an electric vehicle (BEV), it can control the driving force generated by the "electric motor" that serves as the vehicle's drive source.

[0045] Braking device 30 applies braking force to the wheels. Braking device 30 includes a brake ECU 31, a hydraulic circuit 32, and a brake caliper 33. Hydraulic circuit 32 includes a reservoir (not shown), an oil pump, various valve devices, hydraulic sensors, etc. Brake caliper 33 is a hydraulic actuator equipped with a hydraulic cylinder and a piston. When oil is supplied to the hydraulic cylinder, the piston is pushed out of the hydraulic cylinder. A brake pad is located at the top of the piston, which presses against the brake disc. Hydraulic circuit 32 adjusts the hydraulic pressure within the hydraulic cylinder of brake caliper 33 according to commands from brake ECU 31. This controls the braking force exerted by brake caliper 33 on the wheels (brake discs).

[0046] The gear shifting device 40 shifts the gears of the transmission 24. The gear shifting device 40 includes an SBW (Shift-by-Wire) ECU 41, an SBW actuator 42, and a gear shifting mechanism 43. The SBW ECU 41 is connected to the SBW actuator 42. The SBW actuator 42 controls the gear shifting mechanism 43 to shift the gears of the transmission 24 according to the gear shifting command from the SBW ECU 41.

[0047] The surrounding sensor 50 acquires vehicle perimeter information, including information about three-dimensional objects present around the vehicle V and information about road markings around the vehicle V. Three-dimensional objects include moving objects such as cars (other vehicles), pedestrians, and bicycles, and fixed objects such as guardrails and traffic signals.

[0048] The surrounding sensors 50 include a radar sensor 51, an ultrasonic sensor 52, a camera 53, a vehicle speed sensor 54, and a navigation system 55.

[0049] The radar sensor 51 includes a radar transmitter / receiver unit and a signal processing unit (not shown). The radar transmitter / receiver unit transmits millimeter-wave radio waves (hereinafter referred to as "millimeter waves") to the area surrounding the vehicle and receives millimeter waves (i.e., reflected waves) reflected by three-dimensional objects present within the transmission range. The signal processing unit obtains (calculates) information representing the distance between the vehicle V and the three-dimensional object, the relative speed between the vehicle V and the three-dimensional object, and the relative position (direction) of the three-dimensional object relative to the vehicle V based on the phase difference between the transmitted millimeter waves and the received reflected waves, the attenuation level of the reflected waves, and the time from the transmission of the millimeter waves to the reception of the reflected waves, and supplies this information to the driver support ECU 10.

[0050] The ultrasonic sensor 52 transmits ultrasonic waves in pulses to a predetermined range around the vehicle and receives reflected waves from objects. Based on the time from the transmission of the ultrasonic wave to the reception of the reflected wave, the ultrasonic sensor obtains (calculates) information such as "the point on the object where the ultrasonic wave is reflected, i.e., the reflection point" and "the distance between the ultrasonic sensor and the object" and supplies it to the driver support ECU 10.

[0051] The camera 53 includes an image capturing device and an image analyzing device. The image capturing device is, for example, a digital camera with a built-in CCD (charge-coupled device) or CIS (CMOS image sensor) image capturing element. The image capturing device is mounted on the upper part of the windshield. The image capturing device captures image data of the foreground of the vehicle at a predetermined frame rate and outputs it to the image analyzing device. The image analyzing device analyzes the acquired image data, extracts (calculates) information related to a target located in front of the vehicle V from the image, and supplies this information to the driver support ECU 10. For example, the image analyzing device identifies the license plate of a preceding vehicle traveling in the direction of travel of the vehicle V. Furthermore, based on the size (area) of the portion of the license plate relative to the overall image acquired from the image capturing device, the image analyzing device extracts (calculates) the inter-vehicle distance and supplies this information to the driver support ECU 10.

[0052] The vehicle speed sensor 54 includes a wheel speed sensor that generates a pulse signal (wheel pulse signal) whenever the wheels of the vehicle rotate a predetermined angle. The vehicle speed sensor 54 measures the number of pulses per unit time of the wheel pulse signal sent from the wheel speed sensor, calculates the rotational speed (wheel speed) of each wheel based on the measured number of pulses, and calculates the speed of the vehicle (actual vehicle speed) based on the wheel speed of each wheel. The vehicle speed sensor 54 sends data representing the calculation result to the driver support ECU 10.

[0053] The navigation system 55 receives GPS signals from multiple satellites and detects the current location (latitude and longitude) of the vehicle V based on the received GPS signals. Additionally, the navigation system 55 stores map data representing a map. The map data includes road information representing roads and signal location information representing the locations of traffic lights. The navigation system 55 sends vehicle location data, indicating the detected current location of the vehicle V, to the driver support ECU 10. Furthermore, the navigation system 55 has the function of calculating the distance between two locations (distance along the road).

[0054] The operating switch 60 includes an operating element 61 (e.g., a push-button type operating element) that is operated by the driver when requesting the start and end of cruise control. When the driver operates the operating element 61 during periods when cruise control is not in operation (when a button is pressed), the operating element 61 sends a cruise control start signal to the driving support ECU 10 indicating that "the driver has requested the start of cruise control (cruise control start request)". Conversely, when the driver operates the operating element 61 during cruise control operation, the operating element 61 sends a cruise control end signal to the driving support ECU 10 indicating that "the driver has requested the end of cruise control (cruise control end request)". Upon receiving the cruise control start signal, the driving support ECU 10 sets the cruise control flag Fa, indicating whether cruise control execution is possible, to "1". Conversely, upon receiving the cruise control end signal, the driving support ECU 10 sets the cruise control flag Fa to "0".

[0055] Additionally, the operating switch 60 includes an operating element 62 (e.g., a push-button switch operating element) for switching between a state that allows the execution of acceleration suppression control (described later) and a state that disables the execution of acceleration suppression control. If the driver operates the operating element 62 during a period when acceleration suppression control is disabled (by pressing a button), the operating element 62 sends an acceleration suppression enable signal to the driving support ECU 10, indicating that "the driver allows the execution of acceleration suppression control." Conversely, if the driver operates the operating element 62 during a period when acceleration suppression control is enabled, the operating element 62 sends an acceleration suppression disable signal to the driving support ECU 10, indicating that "the driver disables the execution of acceleration suppression control." Upon receiving the acceleration suppression enable signal, the driving support ECU 10 sets the acceleration suppression control flag Fb, indicating whether the execution of acceleration suppression control is permitted or not, to "1." Conversely, upon receiving the acceleration suppression disable signal, the driving support ECU 10 sets the acceleration suppression control flag Fb to "0."

[0056] Additionally, the operating switch 60 includes an operating element for specifying a target value Vd for the vehicle speed during constant speed driving control, as described later.

[0057] (Work)

[0058] Next, the cruise control performed by the driving support device 1 will be described. Cruise control includes constant speed control and follow control. Constant speed control is not directly related to this invention. Therefore, only a general description of constant speed control will be given, while follow control will be described in detail.

[0059] When the driver support ECU 10 receives a cruise control start signal from the operation switch 60, it initiates cruise control (ACC). When initiating cruise control, the driver support ECU 10 determines, based on information obtained from the surrounding sensors 50, whether there are other vehicles (leading vehicles) that should be followed.

[0060] <Cruise Control>

[0061] If it is determined that there is no preceding vehicle to follow, the driving support ECU 10 controls the drive unit 20, braking unit 30, and gear shifting device 40 (hereinafter referred to as "drive unit, etc.") to make the speed of its own vehicle match the preset target value Vd.

[0062] <Follow Control>

[0063] On the other hand, when it is determined that there is a preceding vehicle that should be followed, the driver support ECU 10 detects (measures) the distance L between the preceding vehicle and its own vehicle based on the vehicle's surrounding information obtained from the surrounding sensors 50. Furthermore, the driver support ECU 10 calculates the speed and acceleration of the preceding vehicle based on its own vehicle's speed, changes in the distance L, etc. Moreover, the driver support ECU 10 calculates its own vehicle's acceleration based on changes in its own vehicle's speed. Additionally, the surrounding sensors 50 may include an acceleration sensor. In this case, the driver support ECU 10 obtains its own vehicle's acceleration from the acceleration sensor. Furthermore, the driver support ECU 10 calculates a target value Ld for the distance L based on its own vehicle's speed, the speed of the preceding vehicle, etc.

[0064] When the speed of the preceding vehicle relative to the speed of the preceding vehicle (relative speed Vr) is greater than "0", the vehicle-to-vehicle distance L continuously increases. When the vehicle-to-vehicle distance L expands to a level greater than the target value Ld, the driving support ECU 10 sets a target acceleration for the vehicle to make its speed greater than that of the preceding vehicle. Furthermore, it controls the drive system (hereinafter referred to as "acceleration control") to match the vehicle's acceleration with the target acceleration. As a result, the vehicle-to-vehicle distance L, which has increased beyond the target value Ld, begins to recover towards the target value Ld. Then, when the vehicle-to-vehicle distance L matches the target value Ld, the driving support ECU 10 sets the target acceleration of the vehicle to "0". That is, the driving support ECU 10 controls the drive system to make the vehicle travel at the same speed as the preceding vehicle.

[0065] On the other hand, when the speed of the preceding vehicle is less than 0 relative to the speed of the preceding vehicle, the vehicle distance L continuously decreases. When the vehicle distance L decreases to a level less than the target value Ld, the driving support ECU 10 sets a target acceleration for the vehicle to make its speed less than that of the preceding vehicle. Furthermore, it controls the drive system (hereinafter referred to as "deceleration control") to match the vehicle's acceleration with the target acceleration. As a result, the vehicle distance L, which has decreased from the target value Ld, begins to recover towards the target value Ld. Then, when the vehicle distance L matches the target value Ld, the driving support ECU 10 sets the vehicle's acceleration to 0. Furthermore, the target value Ld is related to both the speed of the vehicle and the speed of the preceding vehicle. The ROM 10c stores a database (table) representing the relationship between their speeds and the target value Ld, or parameters specifying the formula for determining the target value Ld. Based on this database or formula, a smaller target value Ld is assigned to a smaller speed, and a larger target value Ld is assigned to a larger speed. In addition, in principle, the driver support ECU10 sets the upper limit of the target acceleration to a predetermined value A greater than "0" (a value predetermined as the upper limit of acceleration that will not cause discomfort to the occupants).

[0066] Here, imagine a situation where there is congestion in the lane your vehicle is traveling in, and a vehicle ahead temporarily accelerates, increasing the distance L between them. In this situation, the congestion may not actually be relieved, and the vehicle ahead may immediately decelerate. In this case, if your vehicle were to follow the vehicle ahead, as mentioned above, the occupants of your vehicle might experience discomfort.

[0067] Therefore, as explained below, the driving support ECU 10 presupposes whether congestion has occurred (or continues) (or whether congestion has eased). Furthermore, when congestion is presumed to have occurred (or continued), the driving support ECU 10 suppresses the acceleration of its own vehicle.

[0068] Specifically, in addition to the inter-vehicle distance L and relative speed Vr (the speed of the preceding vehicle relative to its own vehicle), the driving support ECU10 also estimates whether the congestion has been relieved based on the speed and acceleration of vehicles traveling in adjacent lanes, and switches between a state that prohibits its own vehicle from accelerating and a state that allows its own vehicle to accelerate based on the estimation result.

[0069] More specifically, the driver support ECU 10 initiates acceleration suppression control when the acceleration suppression start condition is met. Specifically, when the acceleration suppression start condition is met, the driver support ECU 10 sets the upper limit of the target acceleration of its own vehicle to "0". Furthermore, the driver support ECU 10 allows deceleration control to be executed even during acceleration suppression control. Additionally, if the execution of acceleration suppression control is prohibited (the driver operates the operation switch 60 to request the prohibition of acceleration suppression control), the driver support ECU 10 will not initiate acceleration suppression control even if the acceleration suppression start condition is met.

[0070] The acceleration inhibition initiation condition consists of the following conditions X, Y, and Z. Furthermore, the acceleration inhibition initiation condition holds under any of the following conditions.

[0071] • The case where (condition X) is true and (condition Y) is true.

[0072] • The case where (condition X) is true, (condition Y) is false, and (condition Z) is true.

[0073] Here, condition X is defined as described below.

[0074] (Condition X) The speed of the vehicle itself is less than the threshold α.

[0075] Furthermore, condition Y consists of condition Y1 and condition Y2. Conditions Y1 and Y2 are defined as described below. And, condition Y is true if conditions Y1 and Y2 are true.

[0076] (Condition Y1) The workshop distance L is smaller than the threshold β.

[0077] (Condition Y2) The relative velocity Vr is smaller than the threshold γ.

[0078] Furthermore, condition Z consists of conditions Z1 to Z4. Conditions Z1 to Z4 are defined as described below. And, condition Z is true if conditions Z1 to Z4 are true.

[0079] (Condition Z1) The workshop distance L is smaller than the threshold δ (>β).

[0080] (Condition Z2) The relative velocity Vr is smaller than the threshold ε (>γ).

[0081] (Condition Z3) The speed Vn of the vehicle in the adjacent lane is smaller than the threshold ζ (>γ).

[0082] (Condition Z4) The acceleration an of vehicles in adjacent lanes is smaller than the threshold η.

[0083] Here, the driving support ECU 10 calculates the speed Vn and acceleration an of vehicles traveling in adjacent lanes based on information obtained from radar sensor 51 and ultrasonic sensor 52, and information obtained from vehicle speed sensor 54. Furthermore, "adjacent lane" refers to a lane traveling in the same direction as the vehicle's own lane. Additionally, "vehicle traveling in adjacent lane" refers to the vehicle closest to the vehicle. Here, the speed Vn and acceleration an can also be the average of the speeds and accelerations of multiple vehicles traveling near the vehicle.

[0084] When the aforementioned acceleration suppression conditions are met, the driver support ECU 10 begins acceleration suppression control. That is, the driver support ECU 10 sets the upper limit of the target acceleration to "0".

[0085] When the acceleration suppression stop condition is met during acceleration suppression control, the driver support ECU 10 stops the execution of acceleration suppression control. That is, the driver support ECU 10 sets the upper limit of the target acceleration to a predetermined value A (>0).

[0086] The acceleration inhibition stopping condition is composed of the following condition W, the above-mentioned condition Y, and condition Z. Furthermore, the acceleration inhibition stopping condition is satisfied under any of the following conditions.

[0087] • (Condition W) is true

[0088] • Cases where (condition W), (condition Y), and (condition Z) are not true.

[0089] Here, condition W is defined as described below.

[0090] (Condition W) The speed of the vehicle itself is smaller than the threshold θ (<α).

[0091] Furthermore, when a predetermined time has elapsed since the start of acceleration suppression control, the driver support ECU 10 will stop the execution of acceleration suppression control even if the acceleration suppression stop condition is not met. Additionally, when acceleration suppression control is enabled (acceleration suppression control flag Fb is "1"), if the driver operates the control unit 62 to request the disabling of acceleration suppression control, the driver support ECU 10 will immediately stop the execution of acceleration suppression control.

[0092] When the driver support ECU 10 stops executing acceleration suppression control, it sets the acceleration suppression control flag Fb to "0" even if the operating element 62 is not operated. In other words, the driver support ECU 10 becomes unable to execute acceleration suppression control. When the vehicle's speed exceeds the threshold Vth, the driver support ECU 10 sets the acceleration suppression control flag Fb to "1". However, if the driver operates the operating element 62 to allow the execution of acceleration suppression control before the vehicle's speed exceeds the threshold Vth, the driver support ECU 10 immediately switches to a state where it can execute acceleration suppression control.

[0093] Furthermore, if there are no adjacent lanes or no vehicles traveling in adjacent lanes, conditions Z3 and Z4 are not met, so the acceleration suppression condition is not met. Therefore, in this case, the driving support ECU10 sets the upper limit of the target acceleration to a predetermined value A.

[0094] Next, refer to Figure 2 as well as Figure 3 The operation of the CPU (hereinafter simply referred to as "CPU") of the driving support ECU10 (the acceleration suppression control start procedure and acceleration suppression control stop procedure that realize the above-mentioned acceleration suppression control start and stop) will be explained in detail.

[0095] Without acceleration suppression control (where the upper limit of acceleration is a predetermined value A), the CPU executes at predetermined time intervals. Figure 2 The acceleration suppression control start procedure is shown. Additionally, while the CPU is executing acceleration suppression control (with the upper limit of acceleration set to "0"), it executes [the following steps] at predetermined time intervals. Figure 3 The acceleration suppression control stop procedure is shown.

[0096] (Accelerate the start of the suppression control procedure)

[0097] The CPU begins processing the acceleration suppression control from step 100, and proceeds to step 101.

[0098] When the CPU enters step 101, it determines whether the acceleration suppression control flag Fb is "1". In other words, the CPU determines whether acceleration suppression control is allowed. If the acceleration suppression control flag Fb is "1" (101: Yes), the CPU proceeds to step 102. Conversely, if the acceleration suppression control flag Fb is "0" (101: No), the CPU proceeds to step 107, ending the acceleration suppression control start process. That is, in this case, the CPU does not initiate acceleration suppression control.

[0099] When the CPU enters step 102, it determines whether condition X is true. If condition X is true (102: Yes), the CPU proceeds to step 103. On the other hand, if condition X is false (102: No), the CPU proceeds to step 107, ending the acceleration suppression control and starting the processing.

[0100] When the CPU enters step 103, it determines whether condition Y is true. If condition Y is true (103: Yes), the CPU proceeds to step 105. On the other hand, if condition Y is false (103: No), the CPU proceeds to step 104.

[0101] When the CPU enters step 104, it determines whether condition Z is true. If condition Z is true (104: Yes), the CPU proceeds to step 105. On the other hand, if condition Z is false (104: No), the CPU proceeds to step 107, ending the acceleration suppression control and starting the processing.

[0102] When the CPU enters step 105, it begins acceleration suppression control. That is, the CPU sets the upper limit of the vehicle's acceleration to "0". Next, the CPU proceeds to step 106. In step 106, the CPU begins measuring over time T. Then, the CPU proceeds to step 107, ending acceleration suppression control and beginning processing.

[0103] (Accelerate the suppression control to stop the procedure)

[0104] The CPU starts the acceleration suppression control stop processing from step 200 and proceeds to step 201.

[0105] When the CPU proceeds to step 201, it determines whether the elapsed time T since the start of acceleration suppression control exceeds a predetermined threshold Tth. If the elapsed time T exceeds the threshold Tth (201: Yes), the CPU proceeds to step 205. On the other hand, if the elapsed time T is less than or equal to the threshold Tth (201: No), the CPU proceeds to step 202.

[0106] When the CPU enters step 202, it determines whether condition W is true. If condition W is true (202: Yes), the CPU proceeds to step 205. On the other hand, if condition W is false (202: No), the CPU proceeds to step 203.

[0107] When the CPU proceeds to step 203, it determines whether condition Y is false. If condition Y is false (203: Yes), the CPU proceeds to step 205. On the other hand, if condition Y is true (203: No), the CPU proceeds to step 204.

[0108] When the CPU enters step 204, it determines whether condition Z is false. If condition Z is false (204: Yes), the CPU proceeds to step 205. On the other hand, if condition Z is true (204: No), the CPU proceeds to step 210 and ends the acceleration suppression control stop process.

[0109] When the CPU enters step 205, it stops executing acceleration suppression control. That is, the CPU sets the upper limit of its own vehicle's acceleration to a predetermined value A. Then, the CPU proceeds to step 206.

[0110] When the CPU enters step 206, it sets the acceleration suppression control flag Fb to "0". Then, the CPU enters step 207.

[0111] When the CPU proceeds to step 207, it determines whether the vehicle's speed exceeds the threshold Vth. If the vehicle's speed exceeds the threshold Vth (207: Yes), the CPU proceeds to step 209. On the other hand, if the vehicle's speed is below the threshold Vth (207: No), the CPU proceeds to step 208.

[0112] When the CPU proceeds to step 208, it determines whether it has received an acceleration suppression permission signal from the operation switch 60 (whether the driver has operated the operation unit 62 to allow the execution of acceleration suppression control). If an acceleration suppression permission signal has been received (208: Yes), the CPU proceeds to step 209. On the other hand, if no acceleration suppression permission signal has been received, the CPU returns to step 207.

[0113] When the CPU enters step 209, it sets the acceleration suppression control flag Fb to "1". Then, in step 210, the CPU ends the acceleration suppression control stop process.

[0114] (Effect)

[0115] As described above, the driver support ECU 10 performs acceleration suppression control when the inter-vehicle distance L is small and the relative speed Vr is small. Furthermore, even when the inter-vehicle distance L is large enough, or the relative speed Vr is large enough, if the speed Vn and acceleration an of adjacent vehicles are small, it is presumed that congestion has not eased, and acceleration suppression control is performed. That is, according to this embodiment, it is possible to suppress the repeated acceleration and deceleration of the vehicle following the preceding vehicle when there is a high probability that the preceding vehicle will repeatedly accelerate and decelerate. Therefore, compared to conventional devices (devices that do not have the function of presuming whether congestion has eased), the discomfort of the vehicle's occupants can be reduced.

[0116] Furthermore, the driver support ECU10 prohibits the execution of acceleration suppression control from the moment it stops until the vehicle's speed exceeds a predetermined threshold. Based on this, frequent execution of acceleration suppression control can be suppressed.

[0117] The present invention is not limited to the above-described embodiments. As described below, various modifications can be adopted within the scope of the present invention.

[0118] In the above implementation, condition Z is defined as "condition Z is true when conditions Z1 to Z4 are true". Alternatively, it can be defined as "condition Z is true when at least one of conditions Z1 and Z2 is true and at least one of conditions Z3 and Z4 is true".

[0119] Furthermore, the driver support ECU 10 can also determine whether the acceleration suppression start condition is met only when the adjacent lane is not a lane for dividing traffic or a right-turn (left-turn) lane, but a lane of the same type as the current lane. Additionally, if the vehicle traveling in the adjacent lane is an emergency vehicle, the driver support ECU 10 can be configured to not use the speed and acceleration of that emergency vehicle as the aforementioned speed Vn and acceleration an.

Claims

1. A driving support device, comprising: The drive unit applies driving force to the drive wheels of its own vehicle; A braking device applies braking force to the drive wheels; Surrounding sensors output information related to objects around the vehicle, i.e., surrounding information; and A driving support control device performs the following following control: based on the surrounding information, it determines a target value for the inter-vehicle distance between its own vehicle and a preceding vehicle traveling directly in front of it, and controls the drive unit and the braking unit in a manner that makes the measured inter-vehicle distance obtained based on the surrounding information consistent with the target value. The driving support device is configured such that… The condition is defined as the case where the workshop distance is smaller than the first threshold. The second condition is defined as the situation where the speed of the preceding vehicle relative to itself is less than the second threshold. The third condition is defined as the situation where a vehicle traveling in the adjacent lane has a speed lower than the third threshold. The fourth condition is defined as the situation where the acceleration of the adjacent vehicles is less than the fourth threshold. The fifth condition is defined as the situation where the distance between the vehicle and the preceding vehicle is less than the fifth threshold, which is less than the first threshold. The sixth condition is defined as the situation where the speed of the preceding vehicle relative to itself is less than the sixth threshold, which is less than the second threshold. The seventh condition is defined as the situation where the vehicle's speed is less than the seventh threshold. The driving support control device performs acceleration suppression control as follows: if one or both of the fifth and sixth conditions are not met and the first to fourth conditions and the seventh condition are met, it controls one or both of the drive device and the braking device in such a way that the acceleration of its own vehicle is below "0".

2. The driving support device according to claim 1, configured as follows: The driving support control device stops the execution of the acceleration suppression control when at least one of the first to fourth conditions no longer exists during the execution of the acceleration suppression control.

3. The driving support device according to claim 2, configured as follows: The driving support control device prohibits the execution of acceleration suppression control from the moment it stops executing the acceleration suppression control until the speed of its own vehicle exceeds a predetermined threshold.

Images