Vehicle descent assist device

Abstract

To suppress an unnecessary operation of getting-out support control.SOLUTION: A getting-out support apparatus includes: a target information acquisition device 12 for acquiring target information related to a target existing behind an own vehicle; and a control unit 10 capable of calculating a prediction time which is predicted to be required until the target comes into contact with or proceeds closest to the own vehicle on the basis of the target information when the own vehicle is stopped and performing getting-out support control for supporting an occupant of the own vehicle to get out safely when the prediction time is a predetermined time threshold or less. The control unit 10 sets a time threshold to a predetermined first time threshold when a detected velocity of the target is a predetermined first velocity or less, and sets the time threshold to a value smaller than the first time threshold when the detected velocity of the target is greater than the first velocity.SELECTED DRAWING: Figure 4

Description

Technical Field

[0001] The present invention relates to a getting-off assistance device capable of suppressing unnecessary operations of getting-off assistance control.

Background Art

[0002] Conventionally, a getting-off assistance device capable of executing getting-off assistance control for assisting a passenger of a vehicle (typically, an automobile) to get off safely has been known. The getting-off assistance device is configured to execute getting-off assistance control when, for example, an obstacle target that may obstruct the safe getting-off of a passenger (in other words, pass by the side of the vehicle) is detected and a getting-off intention of the passenger (typically, an operation of opening a door by the passenger) is detected (see Patent Document 1). Hereinafter, a vehicle equipped with the getting-off assistance device is referred to as "own vehicle".

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

[0004] The getting-off assistance device detects an obstacle target as follows. That is, the getting-off assistance device includes a target information acquisition device (for example, a radar sensor) that can detect a target existing behind the own vehicle and acquire information about the target as target information, and calculates a predicted time (Time To Collision. Hereinafter, also referred to as "TTC") required until the target contacts or comes closest to the own vehicle based on the target information obtained from this target information acquisition device. Then, when TTC is equal to or less than a preset time threshold TTCth, it is determined that the target may obstruct the safe getting-off of the passenger and is detected as an obstacle target.

[0005] TTCth is determined based on the stopping time of the target object. The stopping time is the time from when the driver of the target object perceives danger (for example, when recognizing the act of a passenger getting off the vehicle) until the target object stops after starting braking (starting to apply the brakes), in other words, the sum of the coasting time and the braking time. If the TTC of a certain target object is greater than the stopping time of that target object, the possibility that the target object obstructs the safe getting off of the passenger is low. Therefore, the stopping time can also be said to be the limit value of the time when it is possible to avoid contact or the closest approach with the vehicle. Thus, hereinafter, the stopping time is also referred to as the "avoidable limit time". By determining TTCth based on the avoidable limit time (stopping time), unnecessary getting-off assistance control is not executed for target objects that can avoid contact or the closest approach with the host vehicle by braking.

[0006] The avoidable limit time differs depending on the type of the target object. Among automobiles, motorcycles, motorized bicycles, and bicycles, which are typical vehicles that can be target obstruction objects, bicycles have the longest avoidable limit time, and there is not much difference among the other vehicles. Therefore, usually, TTCth is determined based on the avoidable limit time of bicycles, which have the largest value.

[0007] According to this configuration, when the target object is a bicycle, the getting-off assistance control can be executed at an appropriate timing. However, when the target object is another vehicle (i.e., a car, a motorcycle, and a motorized bicycle), a value much larger than the avoidable limit time of these vehicles will be set as TTCth. For this reason, even when the TTC of these vehicles is sufficiently larger than the avoidable limit time (in other words, if the driver perceives danger and starts braking at this point, the contact or closest approach with the host vehicle can be sufficiently avoided), when the TTC is less than or equal to TTCth, these vehicles will be detected as obstacle targets and the getting-off assistance control will be executed. Thus, in the configuration where TTCth is determined based on the avoidable limit time of a bicycle, for vehicles other than bicycles, there can be a problem that the unnecessary getting-off assistance control is executed in that the control is executed at a timing much earlier than the timing when the execution of the getting-off assistance control is actually necessary.

[0008] Also, when TTCth is set to a value larger than the avoidable limit time of vehicles other than bicycles, the problem of unnecessary operation of the getting-off assistance control may occur for another reason. That is, as described above, the getting-off assistance device calculates the TTC of the target object, and this calculation process is performed only for the target objects that may pass near the side of the host vehicle in the future among the target objects detected by the target object information acquisition device. Specifically, the getting-off assistance device calculates the moving direction of each detected target object based on the target object information, and calculates the TTC of the target object when the extension line of the moving direction passes near the side of the host vehicle.

[0009] Here, due to the limitations of the performance of the current object information acquisition device in detecting the accuracy of distant objects, errors are likely to be included in the object information for distant objects. As a result, errors are likely to occur in the calculation result of the moving direction. Generally, since vehicles other than bicycles travel at higher speeds than bicycles, when a vehicle other than a bicycle is located far behind the host vehicle, errors are likely to occur in the calculation result of the moving direction of these vehicles. As a result, the extension line of the moving direction passes near the side of the host vehicle, and although it is not actually an object for TTC calculation (i.e., there is no possibility of passing near the side of the host vehicle in the future), TTC may be calculated in some cases. In such a case, if TTCth is set to a relatively large value, it is easy for TTC≤TTCth to hold, and there is a high possibility that vehicles other than bicycles will be misdetected as obstructive objects, resulting in the problem that unnecessary alighting assistance control may be executed.

[0010] The present invention has been made to address the above-described problems. That is, one of the objects of the present invention is to provide an alighting assistance device capable of suppressing unnecessary operation of the alighting assistance control.

[0011] The alighting assistance device according to the present invention (hereinafter referred to as "the device of the present invention") includes an object information acquisition device (12) that detects an object existing behind the host vehicle and acquires information regarding the detected object as object information, a control unit (10) that calculates a predicted time (TTC) required for the object to contact or approach the host vehicle based on the object information during parking, and is capable of executing alighting assistance control to assist a safe alighting of an occupant of the host vehicle when the predicted time (TTC) is less than or equal to a predetermined time threshold (TTCth). and includes. The control unit (10) sets the time threshold (TTCth) to a predetermined first time threshold (TTCth1) when the speed (v) of the detected object is less than or equal to a predetermined first speed (v1), and when the speed (v) of the detected object is greater than the first speed (v1) exceeding a predetermined second speed (v2)If so, set the time threshold (TTCth) to be smaller than the first time threshold (TTCth1). predetermined second time threshold (TTCth2) It is configured as follows. It is configured as follows. The first speed (v1) is set based on the speed distribution of bicycles traveling on the road, The first time threshold (TTCth1) is set based on the avoidable limit time of bicycles within a predetermined first speed range, The second speed (v2) is set based on the speed distribution of vehicles other than bicycles traveling on the road, The second time threshold (TTCth2) is set based on the avoidable limit time of vehicles other than bicycles within a predetermined second speed range.

[0012] In the device of the present invention, when the speed of the target detected by the target information acquisition device is less than or equal to the first speed, the time threshold (the time threshold of the predicted time used to determine whether to execute the getting-off assistance control) is set to the first time threshold, and when the speed of the target is greater than the first speed exceeding the second speed If so, set the time threshold to be smaller than the first time threshold second time threshold It is configured as follows. Here, the first speed is set based on the speed distribution of bicycles traveling on the road, and the first time threshold is set based on the avoidable limit time of bicycles within a predetermined first speed range. Also, the second speed is set based on the speed distribution of vehicles other than bicycles traveling on the road, and the second time threshold is set based on the avoidable limit time of vehicles other than bicycles within a second speed range. Note that the first speed range is, for example, the average speed range when a bicycle travels on the road, and the second speed range is, for example, the average speed range when a vehicle other than a bicycle travels on the road. According to this configuration, It is possible to set the time threshold in the case where the target is a vehicle other than a bicycle to a value smaller than the time threshold in the case where it is not. According to this configuration, compared with the configuration in which the time threshold is uniformly determined based on the avoidable limit time of the bicycle, it is possible to delay the start timing of the getting-off assistance control in the case where the target is a vehicle other than a bicycle to an appropriate timing, and as a result, it is possible to suppress both unnecessary operations caused by the start timing of the control being too early and unnecessary operations caused by the performance of the target information acquisition device.

[0019] In the above description, for the sake of helping the understanding of the invention, reference numerals used in the embodiment are attached in parentheses to the constituent elements of the invention corresponding to the embodiment, but each constituent element of the invention is not limited to the embodiment defined by the above reference numerals.

Brief Description of the Drawings

[0020]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Embodiments for Carrying Out the Invention

[0021] (Configuration) Hereinafter, a getting-off assistance device according to an embodiment of the present invention (hereinafter, also referred to as "the present implementation device") will be described with reference to the drawings. As shown in FIG. 1, the present implementation device includes a getting-off assistance ECU 10, and a vehicle speed sensor 11, a radar sensor 12, a door open / close sensor 13, a side mirror indicator 20, a meter panel 21, a buzzer 22, and a speaker 23 connected thereto. The getting-off assistance ECU 10 mainly includes a microcomputer. ECU is an abbreviation for Electronic Control Unit. The microcomputer includes a CPU, a ROM, a RAM, and an interface (I / F), etc., and the CPU realizes various functions by executing instructions (programs, routines) stored in the ROM. Hereinafter, the vehicle equipped with the present implementation device will be referred to as "the host vehicle".

[0022] The getting-off assistance ECU 10 is configured to acquire the signals generated or output by the sensors 11 to 13 every time a predetermined time elapses, and control the elements (devices) 20 to 23 based on the acquired signals. Hereinafter, the getting-off assistance ECU 10 will also be simply referred to as "ECU 10".

[0023] The vehicle speed sensor 11 generates a signal corresponding to the traveling speed of the host vehicle (hereinafter referred to as "vehicle speed"). The ECU 10 acquires the signal generated by the vehicle speed sensor 11 and calculates the vehicle speed based on the signal. When the vehicle speed is zero, the ECU 10 determines that the host vehicle is in a stopped state (hereinafter also referred to as "during parking").

[0024] The radar sensor 12 (target information acquisition device) has a function of acquiring information on three-dimensional objects (targets) existing behind the host vehicle (directly behind and rearward sides). The three-dimensional objects are moving objects such as vehicles and pedestrians. Vehicles include automobiles, motorcycles, motorized bicycles, and bicycles.

[0025] As shown in FIG. 2, the radar sensor 12 includes a left radar sensor 12L provided at the left corner of the rear bumper (not shown) of the host vehicle V and a right radar sensor 12R provided at the right corner of the rear bumper of the host vehicle V. The radar sensor 12 irradiates radio waves in the millimeter wave band around the host vehicle. Specifically, the left radar sensor 12L irradiates radio waves in a range including the left area RL on the left rear side of the host vehicle, and the right radar sensor 12R irradiates radio waves in a range including the right area RR on the right rear side of the host vehicle. Both the left area RL and the right area RR have a shape that becomes longer in the outer and inner vehicle width directions as they are separated rearward from the host vehicle V. In FIG. 2, for the sake of convenience, the ratio of the areas RL and RR to the host vehicle V is changed and illustrated.

[0026] When a three-dimensional object exists within the radio wave irradiation range, the radar sensor 12 receives the reflected wave from the three-dimensional object. The radar sensor 12 calculates the presence or absence of the three-dimensional object and the relative relationship between the host vehicle and the three-dimensional object (the distance from the host vehicle to the three-dimensional object, the azimuth of the three-dimensional object with respect to the host vehicle, and the relative speed of the three-dimensional object with respect to the host vehicle, etc.) based on the radio wave irradiation timing and reception timing, etc. In other words, the radar sensor 12 detects three-dimensional objects existing behind the host vehicle. Hereinafter, the three-dimensional objects detected by the radar sensor 12 (i.e., the three-dimensional objects existing in the area RL or RR) are also referred to as "targets". The radar sensor 12 outputs this information on the target as target information to the ECU 10.

[0027] Note that the number of radar sensors 12 is not limited to two, and may be one or three or more, as long as the radar sensors 12 can irradiate radio waves within a range including areas corresponding to areas RL and RR. When there is one radar sensor 12, the sensor 12 can be installed, for example, at approximately the center of the rear bumper of the host vehicle V. Also, the sensor for acquiring target information is not limited to the radar sensor 12. For example, instead of or in addition to the radar sensor 12, a laser radar sensor, an ultrasonic sensor, and / or a camera sensor may be used. Alternatively, as the radar sensor 12, a sensor used for blind spot monitor control may be used. Blind spot monitor control is control for alerting the driver of the host vehicle when a vehicle approaching the host vehicle from behind (particularly, a vehicle existing in an area difficult to confirm with a side mirror) is detected.

[0028] Returning to FIG. 1 to continue the description. The door open / close sensor 13 is provided on each of a plurality of doors (more specifically, side doors) of the host vehicle. The door open / close sensor 13 detects the open / closed state of the door. When the door open / close sensor 13 detects that the door is in the open state, during the period in which the open state is detected, an open signal indicating that the door is in the open state is generated. When the door open / close sensor 13 detects that the door is in the closed state, during the period in which the closed state is detected, a closed signal indicating that the door is in the closed state is generated. The ECU 10 detects which of the open signal and the closed signal each of these door open / close sensors 13 is generating, and based on the detection result, detects whether the door corresponding to the door open / close sensor 13 is in the open state or the closed state.

[0029] The side mirror indicator 20 is provided at a predetermined position on each of the left and right side mirrors of the host vehicle, and can be lit and extinguished independently of each other. The meter panel 21 is provided in front of the driver's seat of the host vehicle (at a position visible to the driver). The buzzer 22 is built into the meter panel 21. The speaker 23 is a component of a navigation system (not shown) and is provided in the vicinity of a touch panel display (not shown).

[0030] (Details of operation) Next, the details of the operation of the ECU 10 will be described. In the present embodiment, the ECU 10 executes alarm control (described later) as getting-off assistance control. The alarm control is executed when the alarm condition is satisfied. The alarm condition is satisfied when all of the following conditions 1 to 3 are satisfied.

[0031] (Condition 1) The host vehicle is in a stopped state. (Condition 2) An obstacle target is detected. (Condition 3) The door of the host vehicle is open.

[0032] First, Condition 1 will be described. When the vehicle speed acquired from the vehicle speed sensor 11 is zero, the ECU 10 determines that Condition 1 is satisfied.

[0033] Next, Condition 2 will be described. The obstacle target is a target that may obstruct the safe getting-off of the passengers of the host vehicle (in other words, passes by the side of the host vehicle), and is typically a moving object approaching the host vehicle from behind. The ECU 10 detects the obstacle target as follows. That is, when the ECU 10 determines that there is a target in the left area RL or the right area RR based on the target information acquired from the radar sensor 12, the ECU 10 calculates the predicted time (TTC) required for the target to contact or come closest to the host vehicle. When the TTC is equal to or less than a predetermined time threshold TTCth, the ECU 10 detects the target as an obstacle target and determines that Condition 2 is satisfied.

[0034] A more detailed description will be given with reference to FIG. 2. FIG. 2 shows a state in which another vehicle Vt (in this example, an automobile) is approaching the host vehicle V from behind. As shown in FIG. 2, when the host vehicle V is in a stopped state (i.e., when condition 1 is satisfied), the ECU 10 sets an xy coordinate system with the center of the left and right corners of the rear bumper of the host vehicle V as the origin. The x-axis extends in the longitudinal direction of the host vehicle V, and the y-axis extends in the vehicle width direction (left-right direction) of the host vehicle V. That is, the y-axis can also be said to be an axis passing through the left and right corners of the rear bumper.

[0035] In addition, when the host vehicle V is in a stopped state, the ECU 10 sets an intersection determination line L for the host vehicle V. The intersection determination line L is a virtual line set for calculating the TTC, and includes a left intersection determination line LL and a right intersection determination line LR. The left intersection determination line LL extends from the left corner of the rear bumper in the -y-axis direction (outward in the vehicle width direction) on the y-axis, and the right intersection determination line LR extends from the right corner of the rear bumper in the +y-axis direction (outward in the vehicle width direction) on the y-axis. The lengths of the left and right intersection determination lines LL and LR are the same as each other (for example, about 1.3 [m]), and in this embodiment, they are substantially equal to the lengths in the y-axis direction of the regions RL and RR at the left and right corners of the rear bumper. Note that the lengths of the left and right intersection determination lines LL and LR are set in advance by experiments or simulations so that "when a target passes through an arbitrary position on these determination lines LL and LR while the occupant of the host vehicle V is getting out of the vehicle, there is a possibility of contact with the door or the occupant of the host vehicle V".

[0036] When the host vehicle V is in a stopped state, the ECU 10 calculates the velocity vector A of the target (in the example of FIG. 2, another vehicle Vt) based on the target information, and sets the starting point thereof at the proximity portion np of the target. The proximity portion np is the portion of the front end of the target that is closest to the host vehicle V in the y-axis direction. Note that the velocity vector A can be calculated, for example, by time-differentiating the position (distance and azimuth) of the target. That is, the velocity vector A represents the moving direction of the target at the current time.

[0037] When the extension line of the target's velocity vector A intersects either one of the left and right intersection determination lines LL and LR (in other words, the intersection point P of the extension line and the y-axis is located on the intersection determination line L), the ECU 10 calculates the "time predicted to be required until the target intersects the intersection determination line L" (in other words, the time predicted to be required until the target reaches the intersection point P of the extension line of the target's velocity vector A and the intersection determination line L) as TTC. TTC can be calculated by dividing, for example, "the distance from the proximity part np to the intersection point P" by "the current velocity of the target" using the target information.

[0038] When the TTC when the target will intersect the left intersection determination line LL in the future is less than or equal to TTCth, the ECU 10 determines that the target may inhibit the occupant from safely getting off the vehicle from the left door, and detects the target as an inhibiting target for the left door. On the other hand, when the TTC when the target will intersect the right intersection determination line LR in the future is less than or equal to TTCth, the ECU 10 determines that the target may inhibit the occupant from safely getting off the vehicle from the right door, and detects the target as an inhibiting target for the right door. In these cases, the ECU 10 determines that condition 2 is satisfied.

[0039] On the other hand, when the target will intersect either one of the left and right intersection determination lines LL and LR in the future, but the TTC exceeds TTCth, the ECU 10 determines that the target will not (currently) inhibit the occupant from getting off safely, and does not detect the target as an inhibiting target. On the contrary, when the extension line of the target's velocity vector A does not intersect either of the left and right intersection determination lines LL and LR (in other words, the intersection point P of the extension line and the y-axis is not located on the intersection determination line L), TTC cannot be calculated. Therefore, the ECU 10 does not detect the target as an inhibiting target. In these cases, the ECU 10 determines that condition 2 is not satisfied.

[0040] In the example of FIG. 2, the intersection point P is located on the right intersection determination line LR (that is, the other vehicle Vt will intersect the right intersection determination line LR in the future). Therefore, the ECU 10 calculates the TTC for the other vehicle Vt. When the TTC is less than or equal to TTCth, the other vehicle Vt is detected as an obstacle target for the right door. When the TTC exceeds TTCth, the other vehicle Vt is not detected as an obstacle target.

[0041] Subsequently, Condition 3 will be described. When the ECU 10 determines that the door on the side where the obstacle target is detected is in the open state based on the signal acquired from the door open / close sensor 13, it determines that Condition 3 is satisfied (in other words, it determines that the occupant intends to get off the vehicle).

[0042] Next, the warning control will be described. When the warning condition is satisfied, the ECU 10 performs the following processes 1 to 4 as warning control. (Process 1) Turn on the side mirror indicator 20 on the side where the obstacle target is detected. (Process 2) Display a predetermined mark (for example, a mark indicating whether the obstacle target is approaching from the left rear or right rear direction) on the meter panel 21. (Process 3) Sound the buzzer 22. (Process 4) Have the speaker 23 utter a predetermined message (for example, a message such as "Please be careful of the approaching vehicle"). Note that the processes executed as warning control are not limited to the above processes. For example, it may be configured such that at least one of Processes 1 to 4 is executed.

[0043] Incidentally, usually one type of constant is used for TTCth. This constant can be determined based on the avoidable limit time (stopping time) of the target object. However, according to this determination method, there is a possibility that unnecessary warning control may be executed for a specific type of target object. This will be specifically described with reference to FIG. 3. FIG. 3 is a graph defining the relationship between the speeds and stopping distances of four typical types of objects (automobiles, motorcycles, motorized bicycles, and bicycles) that can be target objects of inhibiting objects, and is based on data from the Traffic Accident Comprehensive Analysis Center, a public interest incorporated foundation. Solid lines 30 to 33 represent the behaviors of bicycles, motorized bicycles, motorcycles, and automobiles, respectively. The stopping distance is the distance that the target object moves during the time from the point when the driver of the target object perceives danger (for example, the point when the vehicle occupant's disembarking behavior is recognized) to the point when the target object stops after starting braking. In other words, it is the sum of the coasting distance and the braking distance.

[0044] The slope of the tangent line of the solid line at an arbitrary speed (that is, the speed derivative value of the stopping distance) represents the avoidable limit time of the target object corresponding to the solid line. According to the graph of FIG. 3, when a bicycle is traveling at an average speed (for example, 10 to 20 [km / h]), the avoidable limit time is longer than the avoidable limit time at any speed of vehicles other than bicycles. In other words, when a bicycle is traveling at an average speed, the stopping distance is longer than the stopping distance at any speed of vehicles other than bicycles. Therefore, TTCth is usually determined based on the avoidable limit time of bicycles (that is, the avoidable limit time having the largest value).

[0045] However, according to this determination method, for vehicles other than bicycles, the disembarkation support control will be started at a considerably early timing, so there may be a problem that unnecessary disembarkation support control is executed. In addition, due to the performance of the current radar sensor 12 (there is a limit to the detection accuracy of distant target objects), an error is likely to occur in the calculation result of the moving direction of a target object (that is, a vehicle other than a bicycle) located far behind the host vehicle. As a result, there may be a problem that a target object that does not actually correspond to an inhibiting target object is erroneously detected as an inhibiting target object and unnecessary disembarkation support control is executed.

[0046] Therefore, in order to suppress the unnecessary operation of the above-described alighting assistance control, for vehicles other than bicycles, it is conceivable to set a TTCth having a value smaller than "TTCth determined based on the avoidable limit time of a bicycle". However, in the present embodiment, the radar sensor 12 is not configured to be able to discriminate the type of target. Here, it is known that the speed distribution of bicycles traveling on the road is 1% at 5 [km / h] or less, 54% at 15 [km / h] or less, 42% at 25 [km / h] or less, and 3% above 25 [km / h]. That is, bicycles traveling at a speed of 25 [km / h] or less account for the majority at 97%, and bicycles traveling at a speed above 25 [km / h] are very few. This means that when the speed of a certain target is above 25 [km / h], the possibility that the target is a bicycle is extremely low (in other words, the possibility that the target is a vehicle other than a bicycle is extremely high).

[0047] From the above, in the present embodiment, the ECU 10 is configured to be able to change TTCth according to the speed of the target. This will be specifically described with reference to FIG. 4. FIG. 4 is a map defining the relationship between the speed v of the target and TTCth, and is stored in advance in the ROM of the ECU 10. As shown in FIG. 4, TTCth is maintained at the first time threshold TTCth1 when the speed v of the target is less than or equal to the first speed v1 (v ≦ v1), and is maintained at the second time threshold TTCth2 (<TTCth1) when the speed v of the target is greater than the second speed v2 (>v1) (v2 < v). When the speed v of the target is greater than the first speed v1 and less than or equal to the second speed v2 (v1 < v ≦ v2), TTCth linearly decreases from TTCth1 to TTCth2. When the ECU 10 calculates the speed of the target, it refers to the map shown in FIG. 4, reads out the value corresponding to the speed of the target, and sets the value as TTCth. Note that the ECU 10 calculates the speed of the target based on the vehicle speed acquired from the vehicle speed sensor 11 and the relative speed of the target included in the target information.

[0048] Here, the first speed v1 is set to "a value such that when the target is traveling at a speed satisfying v1 < v, the probability that the target is a bicycle becomes extremely low". In other words, the first speed v1 is set to "a value such that the proportion of bicycles traveling on the road at a speed greater than v1 becomes extremely small". In the present embodiment, the first speed v1 is set to a value such that the proportion of bicycles traveling on the road at a speed greater than v1 is 3%, that is, 25 [km / h]. Also, TTCth1 is set based on the avoidable limit time when a bicycle is traveling at an average speed (for example, 10 to 20 [km / h]) (that is, the slope of the tangent line of the curve 30 at the average speed of the bicycle in FIG. 3). The above average speed of the bicycle corresponds to an example of the "first speed range". Note that TTCth1 may be set based on the avoidable limit time in other speed ranges of the bicycle.

[0049] On the other hand, TTCth2 is set based on the avoidable limit time when a vehicle other than a bicycle is traveling at an average speed (for example, 30 to 60 [km / h]) (that is, the slope of the tangent lines of the curves 31 to 33 at the average speed of the vehicle other than the bicycle in FIG. 3). Note that the above average speed of the vehicle other than the bicycle corresponds to an example of the "second speed range". Also, the second speed v2 is introduced to suppress the operation from becoming unstable due to a sudden change in TTCth. That is, in a configuration where TTCth is set to TTCth1 when v ≤ v1 and TTCth is set to TTCth2 when v1 < v, when v changes around v1, TTCth changes suddenly, and the alighting assistance control repeats stop and execution, resulting in unstable operation. Therefore, the second speed v2 is introduced so that TTCth gradually changes (decreases gradually) when v1 < v ≤ v2. For this reason, the second speed v2 can be set to any value greater than the first speed v1, and for example, can be set to any value selected from the average speed of vehicles other than bicycles (for example, 30 to 60 [km / h]).

[0050] According to the map in FIG. 4, when the speed v of the target is greater than the first speed v1, the ECU 10 sets the TTCth to a value smaller than the TTCth (= TTCth1) when the speed v of the target is less than or equal to the first speed v1. In particular, when the speed v of the target is greater than the second speed v2, the TTCth is set to TTCth2. When v1 < v, it is highly likely that the target is a vehicle other than a bicycle. For this reason, in the present embodiment, the ECU 10 is configured to change the TTCth according to the speed of the target, but substantially, it can also be said that the TTCth is changed according to the type of the target ( "bicycle" and "vehicle other than bicycle"). According to this configuration, when the possibility that the target is a vehicle other than a bicycle is extremely high, the TTCth is changed to a smaller value compared to the case where it is not. For this reason, compared with the configuration in which the TTCth is uniformly determined based on the avoidable limit time of the bicycle regardless of the type of the target, when the target is a vehicle other than a bicycle, it is possible to delay the start timing of the alighting support control to an appropriate timing. As a result, it is possible to suppress both unnecessary operations caused by the start timing of the control being too early and unnecessary operations caused by the performance of the radar sensor 12.

[0051] (Specific operation) Subsequently, the specific operation of the ECU 10 will be described. The CPU of the ECU 10 is configured to repeatedly execute the routine shown by the flowchart in FIG. 5 every time a predetermined time elapses during the period when power is supplied to the ECU 10 (described later).

[0052] At a predetermined timing, the CPU starts processing from step 500 in FIG. 5 and proceeds to step 510 to determine whether the host vehicle is in a stopped state based on the vehicle speed acquired from the vehicle speed sensor 11 (condition 1). When the host vehicle is in a traveling state, the CPU determines "No" in step 510 (that is, determines that condition 1 is not satisfied (the warning condition is not satisfied)), and proceeds to step 595 to temporarily end this routine. On the other hand, when the host vehicle is in a stopped state, the CPU determines "Yes" in step 510 (that is, determines that condition 1 is satisfied), and proceeds to step 520.

[0053] In step 520, the CPU determines whether a target has been detected based on the target information acquired from the radar sensor 12. If no target has been detected, the CPU determines "No" in step 520 and proceeds to step 595 to temporarily end this routine. On the other hand, if a target has been detected, the CPU determines "Yes" in step 520 and proceeds to step 530.

[0054] In step 530, the CPU calculates the velocity vector A of the detected target based on the target information and determines whether the extension line of the velocity vector A intersects either the left or right intersection determination lines LL, LR. If there is no intersection, the CPU determines "No" in step 530 and proceeds to step 595 to temporarily end this routine. On the other hand, if there is an intersection, the CPU determines "Yes" in step 530 and proceeds to step 540.

[0055] In step 540, the CPU calculates the TTC for the detected target and proceeds to step 550. In step 550, the CPU calculates the velocity v of the detected target, reads out the value corresponding to the velocity v with reference to the map shown in FIG. 4, and sets the value to TTCth. That is, TTCth is set according to the velocity v of the target. Thereafter, the CPU proceeds to step 560.

[0056] In step 560, the CPU determines whether TTC≤TTCth holds for the detected target (Condition 2). If TTC>TTCth, the CPU determines "No" in step 560 (i.e., determines that Condition 2 does not hold (the warning condition does not hold)) and proceeds to step 595 to temporarily end this routine. On the other hand, if TTC≤TTCth, the CPU determines "Yes" in step 560 (i.e., determines that Condition 2 holds (the target is an obstructive target)) and proceeds to step 570.

[0057] In step 570, the CPU determines whether the door (the door on the side where the obstacle target is detected) is in an open state based on the signal acquired from the door opening / closing sensor 13. If the door is in a closed state, the CPU determines "No" in step 570 (that is, determines that condition 3 is not satisfied (the alarm condition is not satisfied)), and proceeds to step 595 to temporarily end this routine. On the other hand, if the door is in an open state, the CPU determines "Yes" in step 570 (that is, determines that condition 3 is satisfied (the alarm condition is satisfied)), and proceeds to step 580 to execute alarm control (processes 1 to 4). Thereafter, the CPU proceeds to step 595 to temporarily end this routine.

[0058] The power supply to the ECU 10 continues until a predetermined condition is satisfied even after the ignition switch is turned off. This condition may be configured to be satisfied, for example, when the door is locked, or may be configured to be satisfied when a predetermined parking time has elapsed after the host vehicle has stopped. According to this configuration, the possibility that the control is not executed in a scene where alarm control is required can be reduced, and the alarm control can be executed more appropriately.

[0059] As described above, the getting-off assistance device according to the present embodiment has been described. However, the present invention is not limited to the above embodiment, and various modifications are possible without departing from the object of the present invention.

[0060] For example, the map defining the relationship between the speed v of the target and TTCth is not limited to the configuration of FIG. 4. If the configuration is such that when the speed v of the target is greater than the first speed v1, TTCth is set to a smaller value compared to the case where it is less than or equal to the first speed v1, a threshold value such as the second speed v2 may not be set.

[0061] Also, in the above embodiment, alarm control is executed as getting-off assistance control, but the type of getting-off assistance control is not limited to this. For example, door opening restriction control for restricting the degree of door opening, or door lock control for locking the door may be executed as getting-off assistance control. Alternatively, door opening restriction control or door lock control may be executed as getting-off assistance control in addition to alarm control.

[0062] Furthermore, in the above embodiment, Condition 2 is satisfied when TTC≤TTCth holds for the target object, but the requirements for the satisfaction of Condition 2 are not limited to this. For example, it may be configured such that Condition 2 is satisfied when TTC≤TTCth for the target object continues for a predetermined duration. Also, Condition 3 may be configured to be satisfied when the door on the side where the obstructive target is detected changes from the closed state to the open state. Alternatively, Condition 3 may be configured to be satisfied when an operation in which a passenger operates a door operation unit (typically an inner lever of the door) is detected based on image data captured by a camera installed inside the vehicle (a camera capable of imaging the passengers inside the vehicle).

[0063] Also, in the above embodiment, the warning condition is satisfied when all of Conditions 1 to 3 are satisfied, but the requirements for the satisfaction of the warning condition are not limited to this. For example, the warning condition may not include Condition 3 and may be configured to be satisfied when Conditions 1 and 2 are satisfied. In other words, the warning control may be configured to be executed regardless of whether the passenger intends to get off the vehicle.

[0064] Alternatively, the warning control may be executed in two stages. Specifically, the warning control includes two types of control, namely, normal warning control and mild warning control (control with a milder degree of assistance than the normal warning control). The mild warning control is, for example, control that executes Process 1 described above, and the normal warning control is, for example, control that executes at least one of Processes 2 to 4 described above in addition to Process 1. The mild warning control is executed when Conditions 1 and 2 are satisfied (i.e., when an obstructive target is detected during a stop but the door is in the closed state). The normal warning control is executed when, in addition to Conditions 1 and 2, Condition 3 is further satisfied (i.e., when an obstructive target is detected during a stop and the door is in the open state). When the door is in the closed state, it is impossible to determine whether a passenger is trying to get off the vehicle from the door. In other words, there are two possibilities: one is that the passenger has the intention to get off but has not opened the door at the current time, and the other is that the passenger has no intention to get off and the door remains closed. Therefore, when the door is in the closed state, by executing mild alarm control, it is possible to achieve both "informing passengers with the intention of getting off about the existence of the obstacle mark in advance" and "not bothering passengers without the intention of getting off due to the execution of normal alarm control". In addition, when all of Conditions 1 to 3 are satisfied, instead of normal alarm control, the above-described door opening restriction control or door lock control may be executed as disembarkation support control. Alternatively, in addition to normal alarm control, door opening restriction control or door lock control may be executed as disembarkation support control.

Explanation of Signs

[0065] 10: Disembarkation support ECU, 11: Vehicle speed sensor, 12: Radar sensor, 13: Door opening / closing sensor, 20: Side mirror indicator, 21: Meter panel, 22: Buzzer, 23: Speaker

Claims

【Claim 1】 An object information acquisition device that detects an object existing behind the host vehicle and acquires information regarding the detected object as object information, calculates a predicted time required until the object is predicted to contact or come closest to the host vehicle based on the object information while the vehicle is stopped, and a control unit capable of executing disembarkation support control to support safe disembarkation of an occupant of the host vehicle when the predicted time is equal to or less than a predetermined time threshold, in a disembarkation support device comprising: the control unit, sets the time threshold to a predetermined first time threshold when the speed of the detected object is equal to or less than a predetermined first speed, and sets the time threshold to a predetermined second time threshold smaller than the first time threshold when the speed of the detected object exceeds a predetermined second speed greater than the first speed, is configured as such, the first speed is set based on the speed distribution of bicycles traveling on the road, the first time threshold is set based on the avoidable limit time of bicycles in a predetermined first speed range, the second speed is set based on the speed distribution of vehicles other than bicycles traveling on the road, the second time threshold is set based on the avoidable limit time of vehicles other than bicycles in a predetermined second speed range, a disembarkation support device.

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