Driving assistance systems

Abstract

To provide a driving assist system improved to, when a vehicle moving on a road in the same direction as a pedestrian does halts tentatively and then starts, even if a distance between the vehicle and pedestrian diminishes, minimize a fear that the senses of security of a driver and pedestrian alike may be impaired.SOLUTION: When a tentatively halting object is detected ahead of an own vehicle, a control unit that controls a travel controller decelerates the own vehicle and halts the own vehicle at a predetermined position 120 ahead of the tentatively halting object. Further, when the tentatively halting object is detected ahead of the own vehicle 102 and a pedestrian 112 who moves in the same direction as the own vehicle does laterally ahead of the own vehicle is detected, the control unit estimates the time t1 required from when the own vehicle catches up with the pedestrian until the own vehicle halts and the time t2 required when the own vehicle halts until the pedestrian catches up with the own vehicle. When the sum of the two times falls below a reference value, even if the tentatively halting object is not detected any longer, the own vehicle is kept at a halt.SELECTED DRAWING: Figure 6

Description

Technical Field

[0001] The present invention relates to a driving support device for vehicles such as automobiles.

Background Art

[0002] As one of the driving support devices for vehicles such as automobiles, a driving support device including a target detection device that detects targets around the host vehicle and a control unit that automatically controls the running of the host vehicle based on the detection results of the target detection device is well known. [[ID=?]] [[ID=?]]

[0003] [[ID=?]] For example, in Patent Document 1 below, the target detection device detects a target in front of the vehicle, and the control unit is configured to expand the detection range of the target detection device in the vehicle width direction when the vehicle is stopped compared to when the vehicle is running. A driving support device is described. [[ID=?]] [[ID=?]]

[0004] [[ID=?]] According to this type of driving support device, when the signal in front of the vehicle turns red during the running of the vehicle, the vehicle is automatically decelerated and temporarily stops in front of the signal. In this situation, the detection range of the target detection device can be expanded in the vehicle width direction. Therefore, not only the target in front of the vehicle but also the target on the front side of the vehicle can be detected, so the possibility of detecting an object entering from the side of the vehicle to the front of the vehicle can be improved. Therefore, the safety when the signal turns green and the vehicle starts can be improved. [[ID=?]]

Prior Art Documents

Patent Documents

[0005] [[ID=?]] [[ID=?]]

Patent Document 1

Summary of the Invention

[0006] [[ID=?]] 〔Problems to be Solved by the Invention〕[[ID=?]] It should be noted that there are some tags with "?" in the translation because the original tags seem to be incomplete or have some issues. The content within the tags - and - in the original text is not clear in terms of their specific usage and integrity, so the translation might not be entirely accurate for those parts. But following the rules, the translation above is presented as best as possible.When vehicles and pedestrians travel on narrow roads, the distance between them tends to be small. For example, a vehicle may overtake a pedestrian moving in the same direction and temporarily stop before a traffic light. After overtaking either the pedestrian or the stationary vehicle, the traffic light may turn green and the vehicle may start moving. If the distance between the vehicle and the pedestrian is small when the vehicle starts moving, the sense of security of both the driver and the pedestrian may be compromised. This problem cannot be resolved by the driver assistance device described in Patent Document 1.

[0007] The present invention provides an improved driver assistance device that can reduce the risk of compromising the sense of security of both the driver and pedestrians, even when a vehicle moving on a road in the same direction as a pedestrian temporarily stops and then starts moving again, resulting in a smaller distance between the vehicle and the pedestrian. [Means for solving the problem and the effects of the invention]

[0008] According to the present invention, a driving assistance device (100) is provided, which includes a target detection device (18) for detecting targets around the vehicle (102), a driving control device (80) for controlling the movement of the vehicle, and a control unit (10) for controlling the driving control device, wherein the control unit is configured to control the driving control device to decelerate the vehicle and stop it at a predetermined position (120) before the target (S60) when the target detection device detects a stop target (such as a red traffic light 116) in front of the vehicle (S50).

[0009] When the target detection device (18) detects a stop target (red traffic light 116) in front of the vehicle (102) and a pedestrian (112) moving in the same direction as the vehicle to the front side of the vehicle (S210, S220), the control unit (10) estimates a first time (t1) from when the vehicle catches up with the pedestrian until the vehicle comes to a stop (S230), and estimates a second time (t2) from when the vehicle comes to a stop until the pedestrian catches up with the vehicle (S240). If the sum of the first and second times (t1+t2) is less than a first reference value (tc1) (S250), the control unit (10) controls the driving control device (80) to maintain the vehicle in a stopped state even if the target detection device no longer detects a stop target (S260, S270, S100, S120).

[0010] According to the above configuration, when the target detection device detects a vehicle that needs to be stopped in front of the vehicle and a pedestrian moving in the same direction as the vehicle to the front and side of the vehicle is detected, a first time and a second time are estimated. Furthermore, if the sum of the first and second times is less than the first reference value, the vehicle will remain stopped even if the target detection device no longer detects a vehicle that needs to be stopped.

[0011] Therefore, when the sum of the first and second times is small, that is, when the time from when the vehicle catches up to the pedestrian until the pedestrian catches up to the vehicle is short and the distance between the vehicle and the pedestrian is small, the vehicle will not start moving even if the vehicle that should stop is no longer detected. Thus, it is possible to prevent the vehicle from starting when the distance between the vehicle and the pedestrian is small, and the risk of the driver's and pedestrian's sense of security being undermined due to the vehicle starting when the distance between the vehicle and the pedestrian is small can be reduced. [Aspects of the Invention]

[0012] In one embodiment of the present invention, the control unit (10) is configured to maintain its own vehicle (102) in a stopped state and, when the target detection device (18) detects a pedestrian (112) in front of the vehicle, and the target detection device no longer detects a stop target (such as a red traffic light 116), estimate a third time (t3) until the vehicle catches up with the pedestrian, and if the third time is less than a second reference value (tc2), continue to maintain the vehicle in a stopped state (S290).

[0013] According to the above embodiment, if the third time until the vehicle catches up with the pedestrian is less than the second standard value, the vehicle will remain stationary. Therefore, the risk of the driver and pedestrian losing their sense of security due to the vehicle starting to move when the distance between the vehicle and the pedestrian moving in front of it is small can be reduced.

[0014] In another embodiment of the present invention, the control unit (10) is configured to estimate a first distance (L1) from the position of the vehicle (102) when it catches up with the pedestrian (112) to a predetermined position (120) (S140), and to estimate a first time (t1) based on the vehicle speed (V) when the vehicle catches up with the pedestrian, the deceleration of the vehicle, and the first distance (S240) (S190).

[0015] Furthermore, in another embodiment of the present invention, the control unit (10) is configured to estimate the speed (Vp) of the pedestrian (112), estimate a second distance (L2) from the pedestrian to the vehicle when the vehicle is stopped, and estimate a second time (t2) based on the pedestrian's speed and the second distance (S240).

[0016] Furthermore, in another embodiment of the present invention, the control unit (10) is configured to maintain the vehicle (102) in a stopped state and, when the target detection device (18) detects a pedestrian (112) in front of the vehicle, and the target detection device no longer detects a vehicle that needs to be stopped, control the driving control device so that the vehicle speed of the vehicle changes according to a preset change pattern (S40). The control unit (10) is also configured to estimate a third distance (L3) from the vehicle to the pedestrian when the target detection device no longer detects a vehicle that needs to be stopped (such as a red traffic light 116), and to estimate a third time (t3) based on the change pattern, the pedestrian's speed, and the third distance (S280).

[0017] In this application, "objects requiring a temporary stop" means objects that are located in front of a moving vehicle and require the vehicle to stop, such as red traffic lights, pedestrian crossings where there are no traffic lights and pedestrians are crossing, road signs indicating a stop (including road markings), and preceding vehicles that stop before these.

[0018] Other objects, features, and associated advantages of the present invention will be readily apparent from the description of embodiments of the present invention, which will be described with reference to the following drawings. [Brief explanation of the drawing]

[0019] [Figure 1] This is a schematic diagram showing a driver assistance device according to an embodiment. [Figure 2] This is a flowchart of the control of stopping and starting in the embodiment. [Figure 3] This is a flowchart of flag control in the embodiment. [Figure 4] This diagram shows the pattern of change in vehicle speed when a vehicle comes to a complete stop and then starts moving again. [Figure 5] This figure shows examples of changes in vehicle speed and changes in the distance between the vehicle and pedestrians. [Figure 6] This figure shows an example of the operation of the embodiment.

Best Mode for Carrying Out the Invention

[0020] The driving support device according to an embodiment of the present invention will be described in detail below with reference to the attached drawings.

[0021] As shown in FIG. 1, a driving support device 100 according to an embodiment of the present invention is applied to a vehicle 102 and includes a driving support ECU 10. The vehicle 102 is a vehicle capable of autonomous driving and includes a drive ECU 20, a brake ECU 30, an electric power steering ECU 40, and a meter ECU 50. An ECU means an electronic control unit (Electronic Control Unit) having a microcomputer as a main part. In the following description, electric power steering is referred to as EPS.

[0022] The microcomputer of each ECU includes a CPU, a ROM, a RAM, a readable and writable non-volatile memory (N / M), an interface (I / F), and the like. The CPU realizes various functions by executing instructions (programs, routines) stored in the ROM. Further, these ECUs are connected to each other so as to be able to exchange data (communicate) via a CAN (Controller Area Network) 104. Therefore, the detection value of a sensor (including a switch) connected to a specific ECU is also transmitted to other ECUs.

[0023] The driving support ECU 10 is a central control device that performs driving support control such as following inter-vehicle distance control and lane keeping control. In the embodiment, the driving support ECU 10, as will be described in detail later, cooperates with other ECUs to execute stop and start control and flag control as part of the following inter-vehicle distance control. The following inter-vehicle distance control is referred to as ACC (Adaptive Cruise Control).

[0024] The driver assistance ECU 10 is connected to a camera sensor 12, a radar sensor 14, and a setting control unit 16. The camera sensor 12 and radar sensor 14 each include multiple camera devices and multiple radar devices, respectively. The camera sensor 12 and radar sensor 14 function as a target detection device 18 that detects targets around the vehicle 102.

[0025] Each camera device of the camera sensor 12, although not shown in the figure, includes a camera unit that photographs the area around the vehicle 102 and a recognition unit that analyzes the image data obtained from the camera unit to recognize landmarks such as road markings, traffic lights, road signs, and other vehicles. The recognition unit supplies information about the recognized landmarks to the driver assistance ECU 10 at predetermined intervals.

[0026] Each radar device of the radar sensor 14 is equipped with a radar transceiver and a signal processing unit (not shown). The radar transceiver emits millimeter-wave radio waves (hereinafter referred to as "millimeter waves") and receives millimeter waves (i.e., reflected waves) reflected by three-dimensional objects (e.g., other vehicles, pedestrians, etc.) within the emission range. The signal processing unit supplies information representing the distance between the vehicle and the three-dimensional object, the relative speed between the vehicle and the three-dimensional object, and the relative position (direction) of the three-dimensional object to the vehicle at predetermined intervals, 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. LiDAR (Light Detection And Ranging) may be used instead of the radar sensor 14.

[0027] The setting control 16 is located in a position accessible to the driver, similar to a steering wheel (not shown in Figure 1), and is operated by the driver. Although not shown in Figure 1, the setting control 16 includes an ACC switch. The driver assistance ECU 10 performs ACC when the ACC switch is ON, as will be described in detail later.

[0028] The drive ECU 20 is connected to a drive unit 22 that accelerates the vehicle 102 by applying driving force to the drive wheels 24. Normally, the drive ECU 20 controls the drive unit 22 so that the driving force generated by the drive unit 22 changes in accordance with the driver's driving operation, and when it receives a command signal from the driver assistance ECU 10, it controls the drive unit 22 based on the command signal.

[0029] The braking ECU 30 is connected to a braking device 32 that decelerates the vehicle 102 by applying braking force to the wheels 34. Normally, the braking ECU 30 controls the braking device 32 so that the braking force generated by the braking device 32 changes in accordance with the driver's braking operation. When it receives a command signal from the driver assistance ECU 10, it performs automatic braking by controlling the braking device 32 based on the command signal. When braking force is applied to the wheels, brake lights (not shown in Figure 1) are illuminated.

[0030] The EPS / ECU 40 is connected to the EPS device 42. Based on the steering torque Ts and vehicle speed V detected by the driving operation sensor 60 and vehicle condition sensor 70 (described later), the EPS / ECU 40 controls the steering assist torque by controlling the EPS device 42 in a manner known in the art, thereby reducing the driver's steering burden. Furthermore, by controlling the EPS device 42, the EPS / ECU 40 can steer the steering wheels 44 as needed. Therefore, the EPS / ECU 40 and the EPS device 42 function as an automatic steering system that automatically steers the steering wheels as needed.

[0031] As can be seen from the above explanation, the drive ECU 20, drive unit 22, brake ECU 30, brake unit 32, EPS ECU 40, and EPS unit 42 function as a driving control device 80 that controls the driving of the vehicle 102, including braking, driving, turning, etc.

[0032] A touch panel display unit 52 is connected to the meter ECU 50 to display the status of control by the driver assistance ECU 10. The display unit 52 may be, for example, a multi-information display that displays meters and various other information, or it may be the display of a navigation device 0, which is not shown in the figure. When the display unit 52 receives a command signal from the driver assistance ECU 10, it displays the status of the ACC.

[0033] The driving operation sensor 60 and the vehicle condition sensor 70 are connected to CAN 104. Information detected by the driving operation sensor 60 and the vehicle condition sensor 70 (referred to as sensor information) is transmitted to CAN 104. The sensor information transmitted to CAN 104 can be used as appropriate by each ECU. Note that the sensor information may be information from a sensor connected to a specific ECU and transmitted to CAN 104 from that specific ECU.

[0034] The driving operation sensor 60 includes a drive operation amount sensor for detecting the amount of operation of the accelerator pedal, a braking operation amount sensor for detecting master cylinder pressure or the force applied to the brake pedal, and a brake switch for detecting whether or not the brake pedal is operated. Furthermore, the driving operation sensor 60 includes a steering angle sensor for detecting the steering angle θ, a steering torque sensor for detecting the steering torque Ts, and the like.

[0035] The vehicle state sensor 70 includes a vehicle speed sensor for detecting the vehicle speed V of the vehicle 102, a longitudinal acceleration sensor for detecting the acceleration of the vehicle in the longitudinal direction, a lateral acceleration sensor for detecting the acceleration of the vehicle in the lateral direction, and a yaw rate sensor for detecting the yaw rate of the vehicle.

[0036] In this embodiment, the ROM of the driver assistance ECU 10 stores a stop and start control program corresponding to the flowchart shown in Figure 2 and a flag control program corresponding to the flowchart shown in Figure 3. The CPU of the driver assistance ECU 10 provides driver assistance by executing stop and start control and flag control according to these programs. <Control of stopping and starting (Figure 2)>

[0037] Next, the control of stopping and starting in the embodiment will be described with reference to the flowchart shown in Figure 2. The control of stopping and starting according to the flowchart shown in Figure 2 is repeatedly executed at predetermined intervals by the CPU of the driver assistance ECU 10 when the ACC switch of the setting control device 16 shown in Figure 1 is ON. At the start of the control according to the flowchart shown in Figure 2, the flag Fss is reset to 0.

[0038] First, in step S10, the CPU determines whether the vehicle 102 is stopped or not based on information from the driving control device 80. If the CPU determines that the vehicle 102 is stopped, it proceeds to step S100; if it determines that the vehicle 102 is stopped, it proceeds to step S20.

[0039] In step S20, the CPU determines whether the flag Fss is 1, that is, whether the vehicle 102 is moving after coming to a complete stop. If the CPU determines it to be true, it proceeds to step S70; if it determines it to be false, it proceeds to step S30.

[0040] In step S30, the CPU determines whether or not there is a stop target in front of the vehicle 102 by determining whether the target detection device 18 has detected a stop target in front of the vehicle 102. If the CPU makes a positive determination, it proceeds to step S50; if it makes a negative determination, it proceeds to step S40.

[0041] In step S40, the CPU performs normal ACC, i.e., constant speed driving control and preceding vehicle following control. Constant speed driving control is a control that adjusts the acceleration and deceleration of the vehicle so that the vehicle's speed matches the target speed (set speed) without requiring any acceleration or deceleration operation by the driver. Preceding vehicle following control is a control that makes the vehicle follow the preceding vehicle (the vehicle being followed) while maintaining the distance between the vehicle 102 and the preceding vehicle (the vehicle being followed) at the target distance, without requiring any acceleration or deceleration operation by the driver.

[0042] In step S50, the CPU calculates a target deceleration Gbt to stop the vehicle 102 at the predetermined position, based on the distance L12 (see Figure 6) from the vehicle 102 to a predetermined position before the stop target detected by the target detection device 18, and the vehicle speed V of the vehicle 102. The predetermined position before the stop target may be set in advance for each stop target.

[0043] In step S60, the CPU controls the deceleration of the vehicle 102 to the target deceleration Gbt by outputting a command signal to the driving control device 80.

[0044] In step S70, the CPU controls the movement of the vehicle 102 by outputting a command signal to the driving control device 80 to control the vehicle speed V of the vehicle 102 to change in a predetermined change pattern A shown in Figure 4(A). The acceleration and constant vehicle speed Vca (positive constant) in the predetermined change pattern A are smaller than the acceleration and constant vehicle speed Vcb (positive constant) in the predetermined change pattern B in normal ACC shown in Figure 4(B).

[0045] In step S80, the CPU determines whether the vehicle speed V of vehicle 102 has reached a constant vehicle speed Vca. If the CPU determines it is negative, it terminates this control; if it determines it is positive, in step S90, it resets the flag Fss to 0 and then terminates this control.

[0046] In step S100, the CPU determines whether the flag Fsk is 1, that is, whether the vehicle 102 should be kept in a stopped state. If the CPU determines it to be positive, it proceeds to step S120; if it determines it to be negative, it proceeds to step S110.

[0047] In step S110, the CPU determines whether or not it is permissible to start vehicle 102. If the CPU determines that it is permissible, it proceeds to step S130; if it determines that it is permissible, it proceeds to step S120. Note that the CPU may determine that it is permissible to start vehicle 102 when there are no longer any objects that should be temporarily stopped in front of vehicle 102, such as when a traffic light changes from red to green, and there are no obstacles such as stopped vehicles in front of vehicle 102.

[0048] In step S120, the CPU outputs a command signal to the driving control device 80 to maintain the vehicle 102 in a stopped state, and then terminates this control.

[0049] In step S130, the CPU sets the flag Fss to 1, and in step S140, the CPU outputs a command signal to the driving control device 80 to start the vehicle 102 moving, and then terminates this control. <Flag control (Figure 3)>

[0050] Next, the control of flag Fsk in the embodiment will be described with reference to the flowchart shown in Figure 3. The control of flag Fsk according to the flowchart shown in Figure 3 is repeatedly executed at predetermined intervals by the CPU of the driver assistance ECU 10 when the ACC switch of the setting control device 16 shown in Figure 1 is ON. Flag Fsk is reset to 0 at the start of the control according to the flowchart shown in Figure 3.

[0051] First, in step S210, the CPU, similar to step S30, determines whether or not there is a stop target in front of the vehicle 102 by determining whether or not a stop target has been detected in front of the vehicle 102 by the target detection device 18. If the CPU determines that there is no stop target, it proceeds to step S300; if it determines that there is no stop target, it proceeds to step S220.

[0052] In step S220, the CPU determines whether there is a pedestrian moving in the same direction as the vehicle to the left front of the vehicle 102 by determining whether a pedestrian has been detected to the left front of the vehicle 102 by the target detection device 18. If the CPU determines that there is no pedestrian, it proceeds to step S300; if it determines that there is no pedestrian, it proceeds to step S230.

[0053] In step S230, the CPU estimates the distance L11 (see Figure 6) between the vehicle 102 and the pedestrian, and the pedestrian's speed Vp. Based on the distance L11, the pedestrian's speed Vp, the vehicle speed V of the vehicle 102, and the target deceleration Gbt, the CPU calculates the time t11 until the vehicle 102 catches up with the pedestrian. The CPU also estimates the distance L12 from the vehicle 102 to a predetermined position 120 (see Figure 6) before the traffic light 116, and based on the vehicle speed V, the target deceleration of the vehicle, and the distance L12, the CPU calculates the time t12 until the vehicle 102 stops. Furthermore, based on times t11 and t12, the CPU calculates the first time t1 (= t12 - t11) from when the vehicle 102 catches up with the pedestrian until it stops.

[0054] The first time t1 may be estimated based on the first distance L1 from the position of the vehicle 102 when it catches up with the pedestrian 112 to a predetermined position 120, the vehicle speed V when the vehicle catches up with the pedestrian, the target deceleration of the vehicle, and the first distance.

[0055] In step S240, the CPU estimates the distance L2 between the vehicle 102 and the pedestrian when the vehicle 102 is stopped, and the pedestrian's speed Vp. Furthermore, based on the distance L2 and the pedestrian's speed Vp, the CPU calculates a second time t2 (=L2 / Vp) until the pedestrian catches up to the stationary vehicle 102.

[0056] In step S250, the CPU determines whether the vehicle 102 should be kept in a stopped state by checking whether the sum of the first time t1 and the second time t2, t1+t2, is less than the first reference value tc1 (a positive constant). If the CPU makes a negative determination, it proceeds to step S300 of the control; if it makes a positive determination, in step S260, it sets the flag Fsk to 1 and then proceeds to step S270 of the control.

[0057] In step S270, the CPU, similar to step S220, determines whether there is a pedestrian moving in the same direction as the vehicle in front of the left side of the vehicle 102 by determining whether a pedestrian has been detected in front of the left side of the vehicle 102 by the target detection device 18. If the CPU determines that there is a pedestrian, it repeats step S270; if it determines that there is a pedestrian, it proceeds to step S280. If the determination in step S270 remains negative for a predetermined determination criterion time (a positive constant) or longer, such as when the pedestrian has veered off onto a side road, the control may proceed to step S300.

[0058] In step S280, the CPU estimates the distance L3 (see Figure 6) between the stationary vehicle 102 and the pedestrian. Furthermore, based on the distance L2, the pedestrian's speed Vp, and the vehicle speed V of the vehicle 102 which changes according to a predetermined change pattern A shown in Figure 4(A), the CPU calculates a third time t3, which is the time from when the pedestrian catches up to the stationary vehicle 102 until the vehicle 102 catches up to the pedestrian.

[0059] In step S290, the CPU determines whether the vehicle 102 should be kept in a stopped state by checking whether the third time t3 is less than the second reference value tc2 (a positive constant). If the CPU makes a positive determination, it returns the control to step S270; if it makes a negative determination, in step S300, it resets the flag Fsk to 0. <Example of operation of the embodiment>

[0060] Figure 6 shows a situation where a vehicle 102 is traveling on a left-hand road 110, and a pedestrian 112 is moving along the left side of the road 110 in the same direction as the vehicle 102. There is a sidewalk 114 on the road 110, and a traffic light 116 is installed on the sidewalk. A stop line 118 is set before the sidewalk 114. When the traffic light 116 is red, the vehicle is required to stop. In Figure 6(A), the position of vehicle 102', shown by the dashed line, is the predetermined position 120 before the stop point. Although not shown in Figure 6, if there is a preceding vehicle that has stopped, the predetermined position before the stop point is a predetermined distance behind the stopped vehicle.

[0061] (A) The traffic light 116 turns red, (B) Vehicle 102 catches up to pedestrian 112, (C) Vehicle 102 stops at the designated position 120, and (D) Pedestrian 112 catches up to the stationary vehicle 102. Furthermore, (E) Pedestrian 112 moves in front of the stationary vehicle 102, and (F) Vehicle 102 catches up to pedestrian 112.

[0062] In (A), the determinations in steps S10 and S20 become negative, and the determination in step S30 becomes positive. Therefore, as steps S50 and S60 are executed, the vehicle 102 is decelerated and stops at the predetermined position 120 (C). As a result, the determination in step S10 becomes positive, but when the flag Fsk is 0, the determinations in steps S100 and S110 become negative, so the vehicle 102 is maintained in a stopped state (S120).

[0063] Furthermore, in (A), the judgments in steps S210 and S220 become affirmative, and in steps S230 and S240, the first time t1 and the second time t2 are calculated, respectively. If the sum of the first time t1 and the second time t2, t1+t2, is less than the reference value tc1, then in step S250, an affirmative judgment is made, and in step S260, the flag Fsk is set to 1. Therefore, the judgment in step S100 becomes an affirmative judgment, and the vehicle 102 is maintained in a stopped state (S120).

[0064] When pedestrian 112 catches up to the stationary vehicle 102 (D) and moves further forward (E), the judgment in step S270 becomes positive, and in step S280, a third time t3 is calculated. If the third time t3 is greater than or equal to the reference value tc2, a negative judgment is made in step S290, and in step S300, the flag Fsk is reset to 0. As a result, the judgment in step S100 becomes negative, so for example, when the traffic light 116 turns green and it is OK for vehicle 102 to start moving, the judgment in step S110 becomes positive. Therefore, in step S130, the flag Fss is set to 1, and in step S140, vehicle 102 starts moving.

[0065] The judgment in step S10 becomes a negative judgment, and the judgment in step S20 becomes a positive judgment. Therefore, in step S70, the vehicle speed V of vehicle 102 is controlled to change according to the predetermined change pattern A shown in Figure 4(A). Furthermore, when the vehicle speed V of vehicle 102 increases and reaches a constant speed Vca, the judgment in step S80 becomes a positive judgment. Therefore, in step S90, the flag Fss is reset to 0. Consequently, the judgments in steps S10 and S20 become negative judgments.

[0066] As can be seen from the above explanation, according to the embodiment, when the target detection device 18 detects a red traffic light 116 as a stop target in front of the vehicle 102 and a pedestrian 112 moving in the same direction as the vehicle to the front side of the vehicle, a first time t1 and a second time t2 are calculated (S210~S240). Furthermore, when the sum of the first and second times t1+t2 is less than the first reference value tc1 (S250), the vehicle is maintained in a stopped state even if the target detection device no longer detects a stop target (S260, S100, S120).

[0067] Therefore, when the sum of the first and second time periods t1+t2 is small, that is, when the time from when the vehicle 102 catches up to the pedestrian 112 until the pedestrian catches up to the vehicle is short, and the distance between the vehicle and the pedestrian is small, the vehicle will not start moving even if the object to stop is no longer detected. Thus, it is possible to prevent the vehicle from starting when the distance between the vehicle and the pedestrian is small, and the risk of the driver and pedestrian losing their sense of security due to the vehicle starting when the distance between the vehicle and the pedestrian is small can be reduced.

[0068] Furthermore, according to the embodiment, if the third time t3 until the vehicle 102 catches up with the pedestrian 112 is less than the second reference value tc2 (S280, S290), the vehicle is kept in a stationary state (S100, S120). Therefore, the risk of the driver and pedestrian losing their sense of security due to the vehicle starting to move when the distance between the vehicle and the pedestrian moving in front of it is small can be reduced.

[0069] Furthermore, according to the embodiment, a first distance L1 from the position of the vehicle 102 when it catches up with the pedestrian 112 to a predetermined position 120 is estimated, and a first time t1 is calculated based on the vehicle speed V when the vehicle catches up with the pedestrian, the target deceleration Gbt of the vehicle, and the first distance (S230). Thus, a first time can be estimated based on the first distance, the vehicle speed when the vehicle catches up with the pedestrian, the target deceleration, and the first distance.

[0070] Furthermore, according to the embodiment, the pedestrian's speed Vp is estimated, a second distance L2 from the pedestrian to the vehicle when the vehicle is stopped is calculated, and a second time t2 is calculated based on the pedestrian's speed and the second distance (S240). Therefore, a second time can be estimated based on the second distance and the pedestrian's speed.

[0071] Furthermore, according to the embodiment, when the vehicle 102 is kept in a stopped state and a pedestrian 112 is detected to the front and side of the vehicle, and the vehicle is no longer detected as a stop target, the vehicle speed V of the vehicle is controlled by the driving control device 80 to change according to a preset change pattern (Figure 4(A)) (S70). Furthermore, a third distance L3 from the vehicle to the pedestrian when the vehicle is no longer detected as a stop target is estimated, and a third time t3 is calculated based on the change pattern, the third distance, and the pedestrian's movement speed Vp (S280). Thus, a third time can be estimated based on the third distance from the vehicle to the pedestrian when the vehicle is no longer detected as a stop target, the change pattern, and the pedestrian's movement speed.

[0072] Furthermore, according to the embodiment, when the vehicle 102 starts moving after being kept in a stopped state, the vehicle's movement is controlled so that the vehicle speed V changes according to a predetermined change pattern A shown in Figure 4(A). The acceleration and constant vehicle speed Vca of the predetermined change pattern A are smaller than the acceleration and constant vehicle speed Vcb of the predetermined change pattern B in a normal ACC shown in Figure 4(B). Therefore, the vehicle's acceleration and speed can be lowered compared to when the vehicle 102's movement is controlled so that the vehicle speed V changes according to a predetermined change pattern B, and this also reduces the risk of compromising the sense of security of the driver and pedestrians.

[0073] Although the present invention has been described in detail above with respect to specific embodiments, it will be apparent to those skilled in the art that the present invention is not limited to the embodiments described above, and that various other embodiments are possible within the scope of the present invention.

[0074] For example, in the above embodiment, if an affirmative determination is made in step S290, control is returned to step S270. However, in step S290, if an affirmative determination is made, it is determined whether or not there is a following vehicle. If a negative determination is made, control is returned to step S270, and if an affirmative determination is made, control may proceed to step S300. According to this modified example, if there is a following vehicle, the flag Fsk is reset to 0, and a negative determination is made in step S100. Therefore, even if the traffic light 118 turns green, it is possible to avoid the following vehicle being unable to start due to vehicle 102 remaining in a stopped state.

[0075] Furthermore, in the above-described embodiment, steps S270 to S300 are executed only when the flag Fsk is 1. However, they may also be executed when the flag Fsk is 0, provided that the vehicle 102 is stopped and there is a pedestrian to the left front of the vehicle.

[0076] Furthermore, although the above-described embodiment is applied to a vehicle 102 traveling on a left-hand road, the present invention may also be applied to a vehicle traveling on a right-hand road. In that case, in steps S220 and S270, it is determined whether or not there is a pedestrian moving in the same direction as the vehicle to the right front of the vehicle 102. [Explanation of Symbols]

[0077] 10...Driver assistance ECU, 12...Camera sensor, 14...Radar sensor, 18...Target detection device, 22...Drive system, 32...Brake system, 42...EPS system, 90...Driving control device, 100...Driver assistance device, 102...Vehicle, 112...Pedestrian, 116...Traffic light, 120...Designated position

Claims

1. A driving assistance system comprising: an object detection device for detecting objects around the vehicle; a driving control device for controlling the vehicle's movement; and a control unit for controlling the driving control device, wherein the control unit is configured to control the driving control device to decelerate the vehicle and stop it at a predetermined position before the object for stopping when the object detection device detects a stop target in front of the vehicle, The control unit is configured to maintain the vehicle in a stopped state by controlling the driving control device when the target detection device detects a vehicle that needs to be stopped in front of the vehicle and a pedestrian moving in the same direction as the vehicle to the front side of the vehicle, estimates a first time from when the vehicle catches up to the pedestrian until the vehicle stops, estimates a second time from when the vehicle stops until the pedestrian catches up to the vehicle, and when the sum of the first and second times is less than a first reference value, even if the target detection device no longer detects the vehicle that needs to be stopped.

2. A driving assistance device according to claim 1, wherein the control unit is configured to maintain the vehicle in a stopped state and, when the target detection device detects the pedestrian in front of and to the side of the vehicle, when the target detection device no longer detects the object to be stopped, estimate a third time until the vehicle catches up to the pedestrian, and when the third time is less than a second reference value, continue to maintain the vehicle in a stopped state.

3. A driving assistance device according to claim 1, wherein the control unit is configured to estimate a first distance from the position of the vehicle when it catches up with the pedestrian to the predetermined position, and to estimate the first time based on the vehicle speed when the vehicle catches up with the pedestrian, the deceleration of the vehicle, and the first distance.

4. A driving assistance device according to claim 1, wherein the control unit is configured to estimate the speed of movement of the pedestrian, estimate a second distance from the pedestrian to the vehicle when the vehicle stops, and estimate a second time based on the speed of movement of the pedestrian and the second distance.

5. The driving assistance device according to claim 2, wherein the control unit is configured to control the driving control device so that the vehicle speed of the vehicle changes in a preset change pattern when the vehicle is kept in a stopped state and the vehicle is detected in front of and to the side of the vehicle by the object detection device, and the vehicle is no longer detected by the object detection device as a target to stop. The control unit is configured to estimate a third distance from the vehicle to the pedestrian when the vehicle is no longer detected by the object detection device as a target to stop, and to estimate a third time based on the change pattern, the pedestrian's speed, and the third distance.

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