Driving assistance devices, driving assistance methods and procedures

Abstract

This invention relates to a driving assistance device, a driving assistance method, and a procedure. The driving assistance device includes: an acceleration control element (32a) operated by a driver of a vehicle to increase the driving force generated by a drive source (34a) of the vehicle; and a control unit capable of performing acceleration limit control to control the vehicle so that its acceleration does not exceed a predetermined limit. The control unit sets a threshold distance that varies depending on the type of the object in front of the vehicle, and performs acceleration limit control when a distance condition is met and a predetermined misoperation condition is met, wherein the distance condition is met when the distance between the vehicle and the object in front is below the threshold distance, and the predetermined misoperation condition is met when the driver erroneously operates the acceleration control element.

Description

Technical Field

[0001] This invention relates to: a driving assistance device that performs acceleration limit control to limit the vehicle's acceleration to a limit acceleration when the driver of a vehicle mistakenly operates an acceleration control; a driving assistance method that performs acceleration limit control when the driver mistakenly operates an acceleration control; and a program that causes a computer to perform acceleration limit control when the driver mistakenly operates an acceleration control. Background Technology

[0002] A known prior art driving assistance device performs acceleration limit control in the event of a malfunction of an acceleration control component. For example, the driving assistance device described in Patent Document 1 (hereinafter referred to as the "prior device") sets a threshold mode based on factors such as the distance between the vehicle and a rear object located behind the vehicle and the road surface slope when the vehicle starts. The prior device uses the threshold mode to determine whether a malfunction of an acceleration control component has occurred, and performs acceleration limit control in the event of such a malfunction.

[0003] Existing technical documents

[0004] Patent documents

[0005] Patent Document 1: Japanese Patent Application Publication No. 2014-19295

[0006] In the presence of rear landmarks and road slope, existing devices can reduce the possibility of misjudging an operation even when no acceleration action has been performed (the possibility of misjudgment), and can reduce the possibility of executing unnecessary acceleration limit controls. However, in the absence of rear landmarks and road slope, existing devices cannot reduce the possibility of misjudgment, and therefore cannot reduce the possibility of executing unnecessary acceleration limit controls.

[0007] In order to reduce the likelihood of unnecessary acceleration limit control being implemented even in the absence of rear landmarks and road slope, the inventors have researched the following driving assistance device (hereinafter referred to as the "research device"). The research device implements acceleration limit control when the driver mistakenly operates an acceleration control component, provided that the distance between the vehicle and a "forward landmark located in front of the vehicle" is below a predetermined threshold distance.

[0008] Generally, drivers adjust the approach distance (approach limit distance) to vary depending on the type of object in front of the vehicle. When the object is a vehicle, the driver shortens this limit distance compared to when the object is a pedestrian.

[0009] The aforementioned research apparatus does not take into account the type of object in front, and therefore cannot sufficiently reduce the possibility of implementing unnecessary acceleration restriction controls. Summary of the Invention

[0010] The present invention was made to address the aforementioned problems. Specifically, one object of the present invention is to provide a driving assistance device that can sufficiently reduce the likelihood of performing unnecessary acceleration limit controls even in the absence of rear landmarks or road surface gradients.

[0011] The driving assistance device of the present invention (hereinafter referred to as "the device of the present invention") comprises:

[0012] An acceleration control element (32a) is operated by the driver of the vehicle to increase the driving force generated by the vehicle's drive source (34a); and

[0013] The control unit (20, 30, 40) is capable of performing acceleration limit control (step 720) to control the vehicle so that the vehicle's acceleration does not exceed a specified limit acceleration (Glmt).

[0014] The control unit is configured to:

[0015] Set different threshold distances based on the category of the forward object located in front of the vehicle (steps 620, 625, 650, 660, 665).

[0016] If the distance condition is met (step 625 is "Yes") and the specified misoperation condition is met (steps 410, 415, 420, 425, and 630 are "Yes"), the acceleration limit control is executed (steps 635, 700 to 795), wherein the distance condition is met when the distance between the vehicle and the target ahead is below the threshold distance, and the specified misoperation condition is met when the driver erroneously operates the acceleration control.

[0017] According to the device of the present invention, acceleration limit control is performed when the distance condition "the distance between the vehicle and the object ahead is a threshold distance" is met, and the erroneous operation condition is met. Therefore, even in the absence of objects behind and road slope, the possibility of performing unnecessary acceleration limit control can be reduced. Furthermore, according to the device of the present invention, a threshold distance is set that varies depending on the type of object ahead. A threshold distance that takes into account the near-limit distance corresponding to the type of object ahead can be set, thus sufficiently reducing the possibility of performing unnecessary acceleration limit control even in the absence of objects behind and road slope.

[0018] In one embodiment of the apparatus of the present invention,

[0019] The control unit is configured to set the threshold distance shorter when the category of the object ahead is a vehicle, compared to when the category of the object ahead is a pedestrian. Figure 2A and Figure 2B ).

[0020] When the object ahead is a vehicle, there is a tendency to overtake or swerve against it. Therefore, compared to when the object ahead is a pedestrian, the approach distance tends to be shorter. According to this solution, a threshold distance that takes into account the approach distance corresponding to the object's category can be set, further reducing the likelihood of implementing unnecessary acceleration limit controls.

[0021] In one embodiment of the apparatus of the present invention,

[0022] The control unit is configured to: establish the erroneous operation condition from the time at least one of the conditions that the operation amount of the acceleration actuator is above a predetermined threshold operation amount and the condition that the operation speed of the acceleration actuator is above a predetermined threshold speed is met (step 410 is "Yes", step 415 is "Yes", first variation) until the predetermined recovery condition that is met when the driver recovers from the erroneous operation of the acceleration actuator is met (step 510 is "Yes").

[0023] In the event that the driver mistakenly operates the accelerator, there is a high probability that the aforementioned operation amount and speed will both exceed a threshold operation amount and a threshold speed. According to this solution, the likelihood of the misoperation condition being met when the driver makes a mistake is increased.

[0024] In one embodiment of the apparatus of the present invention,

[0025] The control unit is configured to perform the acceleration limit control when the vehicle speed, which represents the speed of the vehicle, is below a predetermined threshold speed (step 611 is "Yes"), and the distance condition is met (step 625 is "Yes") and the misoperation condition is met (step 630 is "Yes").

[0026] A scheme to implement acceleration limit control was also considered if the collision time (the time taken until the vehicle collides with the object ahead) falls below a threshold start time. However, at lower vehicle speeds, the collision time tends to be quite large, making it less likely to fall below the threshold start time. Therefore, the likelihood of implementing necessary acceleration limit control decreases. In this solution, at lower vehicle speeds, the decision to implement acceleration limit control is based on the distance to the object ahead. This increases the likelihood of implementing necessary acceleration limit control.

[0027] In one embodiment of the apparatus of the present invention,

[0028] The control unit is configured to set a longer threshold distance as the relative speed of the forward object with respect to the vehicle increases. Figure 2A The MapDvth(Vr) shown is shown. Figure 2B The MapDpth(Vr) shown is shown. Figure 6 The MapDtth(Vr) and MapDoth(Vr) are shown.

[0029] The higher the relative speed, the shorter the time required for the aforementioned collision. In this scheme, a higher relative speed increases the threshold distance, thus allowing acceleration and limiting control to begin earlier at the designated time.

[0030] In one embodiment of the apparatus of the present invention,

[0031] When the target ahead is located in multiple locations, the control unit sequentially sets a threshold distance corresponding to the category of the target ahead, starting from the target ahead that is closest to the vehicle, and determines whether the distance of the target ahead is below the threshold distance (steps 613, 615 to 625, 645 to 665, 670, and 675).

[0032] The control unit makes the distance condition true when there is a target in front at a distance below the threshold distance (step 625 is "Yes").

[0033] According to this solution, the determination can be made sequentially starting from the targets in front whose distance is likely to be below the threshold distance, thus reducing the processing load of the device of the present invention.

[0034] The driving assistance method of the present invention is a driving assistance method that performs acceleration limit control (step 720) to limit the vehicle's acceleration so that it does not exceed a predetermined limit acceleration (Glmt), wherein the driving assistance method includes:

[0035] The first step involves setting different threshold distances based on the category of the object located in front of the vehicle (steps 620, 625, 650, 660, and 665); and

[0036] The second step involves executing the acceleration restriction control (steps 635, 700 to 795) when the distance condition is met (steps 410, 415, 420, 425, and 630 are met) and the specified misoperation condition is met. The distance condition is met when the distance between the vehicle and the target in front is below the threshold distance, and the specified misoperation condition is met when the driver of the vehicle erroneously operates the acceleration control (32a), which is an operation that the driver can operate to increase the driving force generated by the drive source (34a) of the vehicle.

[0037] The program of the present invention is a program for performing acceleration limit control (step 720) to limit the vehicle's acceleration so that it does not exceed a predetermined limit acceleration (Glmt), wherein the program is executed by a computer (20, 30, 40) provided with the vehicle:

[0038] The first step involves setting different threshold distances based on the category of the object located in front of the vehicle (steps 620, 625, 650, 660, and 665); and

[0039] The second step involves executing the acceleration restriction control (steps 635, 700 to 795) when the distance condition is met (steps 410, 415, 420, 425, and 630 are met) and the specified misoperation condition is met. The distance condition is met when the distance between the vehicle and the target in front is below the threshold distance, and the specified misoperation condition is met when the driver of the vehicle erroneously operates the acceleration control (32a), which is an operation that the driver can operate to increase the driving force generated by the drive source (34a) of the vehicle.

[0040] According to the driving assistance method and procedure of the present invention, a threshold distance is set that varies depending on the type of the object ahead. Therefore, a threshold distance that takes into account the approach limit distance corresponding to the type of the object ahead can be set. As a result, even in the absence of rear objects or road slope, the possibility of performing unnecessary acceleration limit control can be sufficiently reduced.

[0041] It should be noted that, in the above description, for the purpose of aiding understanding of the invention, the names and / or reference numerals used in the embodiments described below are enclosed in parentheses to indicate the components of the invention as defined in those embodiments. However, the constituent elements of the invention are not limited to the embodiments specified by the aforementioned names and / or reference numerals. Other objects, features, and accompanying advantages of the invention will be readily understood by referring to the following drawings and the description of the embodiments of the invention. Attached Figure Description

[0042] Figure 1 This is a schematic system configuration diagram of a driving assistance device (this assistance device) according to an embodiment of the present invention.

[0043] Figure 2A This is an illustration of the threshold distance set when the target object ahead is a vehicle.

[0044] Figure 2B This is an illustration of the threshold distance set when the object in front is a pedestrian.

[0045] Figure 3 This is an explanatory diagram illustrating the operation of this auxiliary device.

[0046] Figure 4 It means Figure 1 The flowchart shown is a malfunction detection routine executed by the CPU of the driver assistance ECU.

[0047] Figure 5 It means Figure 1 The flowchart shown is of the recovery decision routine executed by the CPU of the driving assistance ECU.

[0048] Figure 6 It means Figure 1 The flowchart shown is of the execution decision routine executed by the CPU of the driving assistance ECU.

[0049] Figure 7 It means Figure 1 The flowchart shown is a malfunction response control routine executed by the CPU of the driving assistance ECU.

[0050] Explanation of reference numerals in the attached figures:

[0051] 10……Driver assistance device; 20……Driver assistance ECU (DSECU); 30……Engine ECU; 32a……Accelerator pedal; 34a……Drive source; 40……Brake ECU. Detailed Implementation

[0052] One embodiment of the present invention provides a driver assistance device (hereinafter referred to as "this assistance device") 10 mounted on a vehicle VA (see reference). Figure 2A and Figure 2B This auxiliary device 10 includes a driving assistance ECU (hereinafter referred to as "DSECU") 20, a drive ECU 30, and a brake ECU 40. These ECUs are interconnected (communicatively connected) via a CAN (Controller Area Network) not shown.

[0053] ECU is an abbreviation for Electronic Control Unit, an electronic control circuit with a microcomputer as its main component. This microcomputer includes a CPU (Central Processing Unit), ROM (Read-Only Memory), RAM (Random Access Memory), and interfaces. Sometimes, ECU is also referred to as a "control unit," "controller," or "computer." The CPU performs various functions by executing instructions (routes) stored in the memory (ROM). All or several of the aforementioned ECUs 20, ECU 30, and ECU 40 can be integrated into a single ECU.

[0054] Furthermore, this auxiliary device 10 includes multiple wheel speed sensors 21, acceleration sensors 22, camera devices 23, and millimeter-wave radar devices 24.

[0055] Wheel speed sensors 21 are connected to DSECU 20, drive ECU 30, and brake ECU 40 for data exchange. Wheel speed sensors 21 are located on each wheel of the vehicle VA, and each wheel generates a pulse signal whenever it rotates a predetermined angle. DSECU 20, drive ECU 30, and brake ECU 40 measure the number of pulses per unit time of the pulse signals generated by each wheel speed sensor 21, and obtain the rotational speed (wheel speed) of each wheel based on the measured number of pulses. DSECU 10 obtains the vehicle speed Vs, representing the speed of the vehicle VA, based on the wheel speeds of each wheel. As an example, DSECU 10 obtains the average wheel speed of the four wheels as the vehicle speed Vs.

[0056] Accelerometer 22 is connected to DSECU 20 for data exchange. Accelerometer 22 detects the longitudinal acceleration G of vehicle VA and generates a detection signal representing the acceleration G. DSECU 20 determines the acceleration G based on the detection signal from acceleration sensor 22.

[0057] It should be noted that the acceleration sensor 22 can also be configured to detect not only the forward and backward acceleration G of the vehicle VA, but also the left and right acceleration (vehicle width direction) and the up and down acceleration of the vehicle VA.

[0058] The camera device 23 is mounted on the upper part of the front window inside the passenger compartment of the vehicle VA and is connected to the DSECU 20 for data exchange. The camera device 23 acquires image data by capturing the scenery in front of the vehicle VA.

[0059] The camera device 23 includes an image processing ECU 23a. The image processing ECU 23a determines the category of an object based on image data. Specifically, the image processing ECU 23a determines the category of an object by comparing template images of vehicles, pedestrians, and two-wheeled vehicles with images of the objects included in the image data.

[0060] It should be noted that all or part of the functions implemented by the image processing ECU23a can also be implemented by at least one of the other ECUs20, ECU30 and ECU40.

[0061] A millimeter-wave radar device 24 is disposed near the center of the front end of the vehicle VA in the vehicle width direction and is connected to the camera device 23 for data exchange. The millimeter-wave radar device 24 transmits millimeter waves that propagate within a specified range in front of the vehicle VA. These millimeter waves are reflected by other three-dimensional objects (targets) such as other vehicles, pedestrians, and two-wheeled vehicles. The millimeter-wave radar device 24 receives the reflected waves and obtains radar object information based on the reflected waves. The radar object information includes the received result of the reflected waves (power data of the reflected waves), the distance to the target, the lateral position of the target, and the relative speed Vr of the target relative to the vehicle VA, etc.

[0062] The image processing ECU 23a identifies an object (hereinafter sometimes referred to as "forward object") located in front of the vehicle VA based on image data and the "received result of reflected waves included in the radar object information from the millimeter-wave radar device 24," and obtains the distance to the object and the lateral position of the object. Then, the image processing ECU 23a sends the distance D to the object, the lateral position of the object, the relative velocity Vr of the object, and object information including the object's category to the DSECU 20. The relative velocity Vr is set to a positive value in the direction approaching the vehicle VA.

[0063] Furthermore, this auxiliary device 10 includes an accelerator pedal operation amount sensor 32, a drive source actuator 34, a brake pedal operation amount sensor 42, and a brake actuator 44.

[0064] The drive ECU 30 is connected to the accelerator pedal operation sensor 32 and the drive source actuator 34 for data exchange.

[0065] The accelerator pedal operation amount sensor 32 detects the operation amount of the accelerator pedal 32a in the vehicle VA (i.e., the accelerator pedal operation amount AP) and generates a detection signal representing the accelerator pedal operation amount AP. The accelerator pedal 32a is an acceleration control element operated by the driver to increase the driving force generated by the drive source (electric motor and internal combustion engine, etc.) 34a of the vehicle VA. When the driver does not operate the accelerator pedal 32a (i.e., when the driver does not press the accelerator pedal 32a), the accelerator pedal operation amount AP is "0". The greater the amount of time the driver presses the accelerator pedal 32a, the greater the accelerator pedal operation amount AP.

[0066] The drive ECU 30 determines the accelerator pedal operation amount AP based on the detection signal from the accelerator pedal operation amount sensor 32, and notifies the accelerator pedal operation amount AP to the DSECU 20.

[0067] The drive source actuator 34 is connected to the drive source (electric motor, internal combustion engine, etc.) 34a. The drive ECU 30 controls the drive source actuator 34 to change the operating state of the drive source 34a. Thus, the drive ECU 30 can adjust the driving force applied to the vehicle VA. The drive ECU 30 controls the drive source actuator 34 such that the greater the accelerator pedal operation amount AP, the greater the driving force applied to the vehicle VA. Furthermore, when the drive ECU 30 receives acceleration / deceleration commands including a target acceleration Gtgt from the DSECU 20, it controls the drive source actuator 34 to make the acceleration G of the vehicle VA match the target acceleration Gtgt.

[0068] The brake ECU40 is connected to the brake pedal operation sensor 42 and the brake actuator 44 for data exchange.

[0069] Brake pedal operation amount sensor 42 detects the brake pedal operation amount BP, which is the operation amount of the brake pedal 42a of the vehicle VA, and generates a detection signal representing the brake pedal operation amount BP. Brake ECU 40 determines the brake pedal operation amount BP based on the detection signal from brake pedal operation amount sensor 42.

[0070] Brake actuator 44 is connected to a known hydraulic braking device 44a. Brake ECU 40 controls brake actuator 44 to change the frictional braking force generated by braking device 44a. Thus, brake ECU 40 can adjust the braking force applied to vehicle VA. Brake ECU 40 controls brake actuator 44 such that a larger brake pedal operation BP results in a larger braking force applied to vehicle VA. Upon receiving the aforementioned acceleration / deceleration command from DSECU 20, brake ECU 40 controls brake actuator 44 to make the acceleration G of vehicle VA match the target acceleration Gtgt.

[0071] Furthermore, this auxiliary device 10 includes a display 50. The DSECU 20 is connected to the display 50 for data exchange. The display 50 receives display signals from the DSECU 20 and displays the information indicated by the display signals. The display 50 may be a head-up display (hereinafter referred to as "HUD") located in a portion of the windshield of the vehicle's VA (display area), or it may be a multi-information display.

[0072] (Work Summary)

[0073] The auxiliary device 10 determines that the misoperation condition is established when the driver misoperates the accelerator pedal 32a during the period from the establishment of the specified misoperation start condition to the establishment of the specified recovery condition.

[0074] The auxiliary device 10 determines the distance D to the object in front, the lateral position of the object in front, the relative velocity Vr of the object in front, and the category of the object in front based on the object information from the camera device 23. When the distance D to the object in front is below a threshold distance Dth, and the misoperation condition is met, the auxiliary device 10 performs misoperation response control. It should be noted that when there are multiple objects in front, if the distance D to any one of the objects in front is below the threshold distance Dth and the misoperation condition is met, the auxiliary device 10 performs misoperation response control.

[0075] The auxiliary device 10 performs acceleration limit control as a misoperation response control from the start time of the misoperation response control until a predetermined time T1 has elapsed. The acceleration limit control is to control the vehicle VA so that the acceleration G of the vehicle VA does not exceed a predetermined limit acceleration Glmt.

[0076] After a predetermined time T1 has elapsed since the start of the misoperation response control, the auxiliary device 10 performs slow deceleration control as a misoperation response control, which is a control that decelerates the vehicle VA by a predetermined negative acceleration Gsb.

[0077] The feature of this assist device 10 is that it makes the threshold distance Dth different (changes) according to the type of the object in front. This threshold distance Dth is set based on the approach limit distance that a typical driver will have depending on the type of the object in front. Therefore, by changing the threshold distance Dth according to the type of the object, this assist device 10 can reduce the possibility of unnecessary misoperation of the control response despite the driver's intentional operation of the accelerator pedal 32a.

[0078] like Figure 2AAs shown, when the type of the object in front is a vehicle (VB), the auxiliary device 10 obtains the threshold distance Dvth by applying the relative speed Vr of the object in front to the vehicle threshold distance map MapDvth (Vr), and sets the threshold distance Dvth as the threshold distance Dth.

[0079] The relationship between the relative velocity Vr of a target ahead and the threshold distance Dvth is defined based on the vehicle threshold distance mapping MapDvth(Vr). Specifically, according to the vehicle threshold distance mapping MapDvth(Vr), the larger the relative velocity Vr of a target ahead, the longer the threshold distance Dvth.

[0080] like Figure 2B As shown, when the category of the object in front is a pedestrian (PD), the auxiliary device 10 obtains the threshold distance Dpth by applying the relative velocity Vr of the object in front to the pedestrian threshold distance mapping MapDpth (Vr), and sets the threshold distance Dpth as the threshold distance Dth.

[0081] According to the pedestrian threshold distance mapping MapDpth(Vr), the larger the relative velocity Vr of the object in front, the longer the threshold distance Dpth.

[0082] Moreover, such as Figure 2A and Figure 2B As shown, the threshold distance Dvth is set to a value less than the threshold distance Dpth. This is because there is a tendency for the driver's maximum approach distance relative to a vehicle to be shorter than their maximum approach distance relative to a pedestrian. When a driver needs to approach a vehicle in front of them to overtake or catch up, the driver's maximum approach distance relative to the vehicle tends to be shorter.

[0083] Therefore, a threshold distance Dth is set that takes into account the driver's limit approach distance, which varies depending on the type of object, thus reducing the possibility of unnecessary erroneous response control.

[0084] (Work example)

[0085] Reference Figure 3 An example of the operation of this auxiliary device 10 will be described.

[0086] <Time point t1>

[0087] At time point 1, the auxiliary device 10 determines that the malfunction initiation condition has been met. However, the distance D1 to the target ahead at time point t1 is longer than the threshold distance Dth, therefore, the auxiliary device 10 does not perform malfunction response control.

[0088] The erroneous operation begins when all three of the following conditions are met.

[0089] First condition: Vehicle speed Vs is below the threshold vehicle speed Vsth.

[0090] The second condition is that the accelerator pedal operation amount AP is greater than or equal to the threshold operation amount APth.

[0091] The third condition is that the accelerator pedal operation speed Vap is above the threshold operation speed Vapth.

[0092] It should be noted that the above recovery conditions are valid only if the fourth condition below is met.

[0093] Fourth condition: Accelerator pedal operation amount AP is less than the recovery threshold operation amount APcth.

[0094] The recovery threshold operation amount APcth is set to a value less than the threshold operation amount APth. As an example, the recovery threshold operation amount APcth is set to "0". Thus, when the driver's foot leaves the accelerator pedal 32a, the CPU determines that the recovery condition is met.

[0095] <Time point t2>

[0096] At time t2, distance D2 falls below the threshold distance Dth. It is assumed that the recovery condition is not met during the period from time t1 to time t2. Based on this assumption, the auxiliary device 10 determines that the misoperation condition has been met. At time t2, distance D2 falls below the threshold distance Dth, thus the distance condition is met, and the misoperation condition is also met. Therefore, the auxiliary device 10 initiates misoperation response control. More specifically, the auxiliary device 10 performs acceleration limit control as a misoperation response control and issues a first warning. In the first warning, the auxiliary device 10 displays a message on the display 50 that the accelerator pedal 32a has been depressed.

[0097] <Time point t3>

[0098] At time t3, a predetermined time T1 has elapsed since the start of the misoperation response control at time t2. At time t3, the auxiliary device 10 performs slow deceleration control as a misoperation response control and issues a second warning. In the second warning, in addition to the above message, the message "Please press the brake pedal 42a" is also displayed on the display 50.

[0099] <Time point t4>

[0100] At time t4, the auxiliary device 10 determines that the recovery condition is met and the misoperation condition is not met, indicating that the driver did not perform any misoperation. At time t4, the auxiliary device 10 terminates the misoperation response control.

[0101] It should be noted that, in Figure 3The example shown illustrates an instance where the maloperation initiation condition is met at time t1, which is prior to the condition's occurrence at time t2. If the maloperation initiation condition is met after time t2, the auxiliary device 10 initiates maloperation response control at the time the maloperation initiation condition is met.

[0102] (Specific tasks)

[0103] <Error Detection Routine>

[0104] The CPU of DSECU20 (hereinafter, unless otherwise specified, "CPU" refers to the CPU of DSECU20) executes commands at predetermined intervals. Figure 4 The flowchart in the diagram represents the routine (error detection routine).

[0105] Therefore, when the specified timing is reached, the CPU starts from... Figure 4 The process begins at step 400 and proceeds to step 405, where it is determined whether the value of the erroneous operation flag Xeo is "0".

[0106] The value of the misoperation flag Xeo is set to "1" when the misoperation initiation condition is met, and set to "0" when the recovery condition is met. That is, the value of the misoperation flag Xeo is set to "1" when the misoperation condition is met. It should be noted that in the initialization routine executed by the CPU when the ignition key switch (not shown) of the vehicle VA changes from the off position to the on position, the value of the misoperation flag Xeo is set to "0".

[0107] If the value of the erroneous operation flag Xeo is "0", the CPU determines "yes" in step 405 and proceeds to step 410. In step 410, the CPU determines whether the vehicle speed Vs is below the threshold vehicle speed Vsth.

[0108] If the vehicle speed Vs is greater than the threshold vehicle speed Vsth, the CPU determines "No" in step 410, proceeds to step 495, and temporarily terminates this routine.

[0109] If the vehicle speed Vs is below the threshold vehicle speed Vsth, the CPU determines "yes" in step 410 and proceeds to step 415. In step 415, the CPU determines whether the accelerator pedal operation amount AP is above the specified threshold operation amount APth.

[0110] If the accelerator pedal operation amount AP is less than the threshold operation amount APth, the CPU determines "No" in step 415, proceeds to step 495, and temporarily ends this routine.

[0111] On the other hand, if the accelerator pedal operation amount AP is greater than or equal to the threshold operation amount Apth, the CPU determines "yes" in step 415 and proceeds to step 420. In step 420, it is determined whether the accelerator pedal operation speed Vap is greater than or equal to the specified threshold operation speed Vapth.

[0112] The CPU calculates the subtraction value dAP by subtracting the accelerator pedal operation value AP from the previous execution value AP of the same routine. Then, the CPU calculates the accelerator pedal operation speed Vap by dividing the subtraction value dAP by the execution interval dt of the current routine.

[0113] If the accelerator pedal operation speed Vap is less than the threshold operation speed Vapth, the CPU determines "No" in step 420, proceeds to step 495, and temporarily terminates this routine.

[0114] On the other hand, if the accelerator pedal operation speed Vap is above the threshold operation speed Vapth, the CPU determines that the erroneous operation condition has been met. In this case, the CPU determines "yes" in step 420 and proceeds to step 425. In step 425, the CPU sets the value of the erroneous operation flag Xeo to "1" and proceeds to step 495, temporarily ending this routine.

[0115] If the CPU enters step 405 and the value of the error flag Xeo is "1", then the CPU determines "no" in step 405 and enters step 495, temporarily ending this routine.

[0116] <Resumption Decision Routine>

[0117] The CPU executes the command at regular intervals. Figure 5 The flowchart in the diagram represents the routine (recovery decision routine).

[0118] Therefore, when the specified timing is reached, the CPU starts from... Figure 5 The process begins at step 500 and proceeds to step 505, where it is determined whether the value of the erroneous operation flag Xeo is "1".

[0119] If the value of the error flag Xeo is "0", the CPU determines "no" in step 505, proceeds to step 595, and temporarily terminates this routine.

[0120] If the error operation flag is set to "1", the CPU determines "yes" in step 505 and proceeds to step 510. In step 510, the CPU determines whether the accelerator pedal operation amount AP is less than the specified recovery threshold operation amount APcth.

[0121] If the accelerator pedal operation amount AP is greater than or equal to the recovery threshold operation amount APcth, the CPU determines "No" in step 510, proceeds to step 595, and temporarily terminates this routine.

[0122] On the other hand, if the accelerator pedal operation amount AP is less than the recovery threshold operation amount APcth, the CPU determines that the recovery condition is met and the erroneous operation condition is no longer met. In this case, the CPU determines "yes" in step 510 and executes steps 515 to 525 sequentially.

[0123] Step 515: The CPU sets the value of the error flag Xeo to "0".

[0124] Step 520: The CPU sets the value of the execution flag Xexe to "0".

[0125] When performing error handling control, the execution flag Xexe is set to "1"; when not performing error handling control, the execution flag Xexe is set to "0". It should be noted that the CPU sets the execution flag Xexe to "0" in the above initialization routine.

[0126] Step 525: The CPU sets the value of the execution timer Texe to "0".

[0127] The execution timer Texe is a timer used to count the time elapsed since the start of the malfunction response control.

[0128] Then, the CPU proceeds to step 595, temporarily terminating this routine.

[0129] <Execution Decision Routine>

[0130] The CPU executes the command at regular intervals. Figure 6 The flowchart in the diagram represents the routine (execution decision routine).

[0131] Therefore, when the specified timing is reached, the CPU starts from... Figure 6 Step 600 begins processing, proceeding to step 605, where it is determined whether the value of the execution flag Xexe is "0".

[0132] If the value of the execution flag Xexe is “0”, the CPU determines “yes” in step 605 and executes steps 610 and 611 in sequence.

[0133] Step 610: The CPU obtains object information from the camera device 23.

[0134] Step 611: The CPU determines whether the vehicle speed Vs is greater than the specified threshold speed Vsth'. Ideally, the threshold speed Vsth' should be set to a value greater than the threshold speed Vsth, but it can also be set to a value below the threshold speed Vsth. If the threshold speed Vsth' is set to a value below the threshold speed Vsth, the misoperation response control cannot begin if the misoperation start condition is met before the time point at which the condition is met.

[0135] If the vehicle speed Vs is below the threshold speed Vsth', the CPU determines that the vehicle speed Vs is low. In this case, the CPU determines "yes" in step 611 and executes steps 613 and 615 sequentially.

[0136] Step 613: The CPU selects the object in front with the smallest distance D. Hereinafter, this object in front will be referred to as the "selected object".

[0137] Step 615: The CPU determines whether the selected object is a vehicle.

[0138] If the selected object category is vehicle, the CPU determines "yes" in step 615 and executes steps 620 and 625.

[0139] Step 620: The CPU obtains the threshold distance Dvth by applying the relative speed Vr of the selected object to the vehicle threshold distance mapping MapDvth(Vr), and sets the threshold distance Dvth as the threshold distance Dth.

[0140] Step 625: The CPU determines whether the distance D of the selected object is below the threshold distance Dth.

[0141] If the distance D of the selected object is below the threshold distance Dth, the CPU determines "yes" in step 625 and proceeds to step 630. In step 630, the CPU determines whether the value of the erroneous operation flag Xeo is "1".

[0142] If the value of the error operation flag Xeo is "0", the CPU determines "no" in step 630, proceeds to step 695, and temporarily terminates this routine.

[0143] If the value of the error operation flag Xeo is "1", the CPU determines "yes" in step 630 and executes steps 635 and 640 in sequence.

[0144] Step 635: The CPU sets the value of the execution flag Xexe to "1".

[0145] Step 640: The CPU sets the value of the execution timer Texe to "0".

[0146] Then, the CPU proceeds to step 695, temporarily terminating this routine.

[0147] On the other hand, if the category of the selected object is not a vehicle when the CPU enters step 615, the CPU determines "no" in step 615 and proceeds to step 645. In step 645, the CPU determines whether the category of the selected object is a pedestrian.

[0148] If the selected object category is pedestrian, the CPU determines "yes" in step 645 and proceeds to step 625 after executing step 650.

[0149] Step 650: The CPU obtains the threshold distance Dpth by applying the relative velocity Vr of the selected object to the pedestrian threshold distance mapping MapDpth(Vr), and sets the threshold distance Dpth to the threshold distance Dth.

[0150] On the other hand, if the category of the selected object is not pedestrian when the CPU enters step 645, the CPU determines "no" in step 645 and proceeds to step 655. In step 655, the CPU determines whether the category of the selected object is a two-wheeled vehicle.

[0151] If the selected object category is a two-wheeled vehicle, the CPU determines "yes" in step 655 and proceeds to step 625 after executing step 660.

[0152] Step 660: The CPU obtains the threshold distance Dtth by applying the relative speed Vr of the selected object to the two-wheeled vehicle threshold distance mapping MapDtth(Vr), and sets the threshold distance Dtth to the threshold distance Dth.

[0153] On the other hand, if the category of the object selected by the CPU when entering step 655 is not a two-wheeled vehicle (for example, if the object is a wall or guardrail), the CPU determines "no" in step 655 and enters step 625 after executing step 665.

[0154] Step 665: The CPU obtains the threshold distance Doth by applying the relative velocity Vr of the selected object to other threshold distance maps MapDoth (Vr), and sets the threshold distance Doth as the threshold distance Dth.

[0155] It should be noted that, from Figure 6The threshold distance mapping MapDtth(Vr) and other threshold distance mappings MapDoth(Vr) shown can also be understood. As an example, each threshold distance mapping is set up with the longest threshold distance Dpth, the shortest threshold distance Dvth, and the threshold distance Dtth being longer than the threshold distance Doth. Moreover, for any threshold distance Dpth, Dtth, Doth, and Dvth, the threshold distance is set to be longer if the relative speed Vr is faster.

[0156] On the other hand, if the distance D of the selected object is longer than the threshold distance Dth when the CPU enters step 625, the CPU determines "no" in step 625 and proceeds to step 670. In step 670, the CPU determines whether there is a forward object with the second smallest distance D after the selected object.

[0157] If there is a target in front that is the second smallest distance D after the selected target, the CPU determines "yes" in step 670 and proceeds to step 675. In step 675, the CPU selects the target in front that is the second smallest distance D after the selected target as the new selected target and executes the processing after step 615.

[0158] On the other hand, if there is no target in front of the selected target that is the second smallest distance D, the CPU determines "no" in step 670 and proceeds to step 695 to temporarily end the routine.

[0159] In this way, the CPU selects targets in ascending order of distance D, and determines whether the distance D of the selected target is below the threshold distance Dth. Therefore, the CPU can perform the selection sequentially starting from the targets whose distance D is likely to fall below the threshold distance Dth, thus reducing the CPU's processing load.

[0160] On the other hand, if the vehicle speed Vs is greater than the threshold vehicle speed Vsth' when the CPU enters step 611, the CPU determines that the vehicle speed Vs is too high. In this case, the CPU determines "no" in step 611, enters step 695, and temporarily terminates this routine.

[0161] Also consider initiating misoperation response control if the collision time required (hereinafter referred to as "TTC"; TTC is an abbreviation for Time To Collision) is below the specified threshold start time Tsth and the misoperation flag Xeo is set to "1". TTC is the time elapsed until the vehicle VA collides with the object ahead, calculated by dividing the distance D by the relative speed Vr.

[0162] At lower vehicle speeds (Vs), the collision time is more likely to be a large value, making it difficult to fall below the threshold start time (Tsth). Therefore, the likelihood of implementing necessary acceleration limiting control decreases. Furthermore, at higher vehicle speeds (Vs), ideally, acceleration limiting control should not be implemented, but rather control that decelerates the vehicle (VA) should be executed. Therefore, only when the vehicle speed is low is a "yes" decision made in step 611, proceeding to step 613, where a determination is made based on distance (D) to determine whether to implement acceleration limiting control. This increases the likelihood of implementing necessary acceleration limiting control at lower vehicle speeds (Vs).

[0163] <Misoperation Response Control Routine>

[0164] The CPU executes the command at regular intervals. Figure 7 The flowchart in the diagram represents the routine (misoperation response control routine).

[0165] Therefore, when the specified timing is reached, the CPU starts from... Figure 7 Step 700 begins processing, proceeding to step 705, where it is determined whether the value of the execution flag Xexe is "1".

[0166] If the value of the execution flag Xexe is "0", the CPU determines "No" in step 705, proceeds to step 795, and temporarily terminates this routine.

[0167] If the value of the execution flag Xexe is "1", the CPU determines "yes" in step 705 and executes steps 710 and 715 in sequence.

[0168] Step 710: The CPU increments the execution timer Texe by "1".

[0169] Step 715: The CPU determines whether the execution timer Texe is below the threshold Tth. When the execution timer Texe reaches the threshold Tth, the threshold Tth is set to a value equal to the time T1 elapsed since the start of the misoperation response control.

[0170] If the execution timer Texe is below the threshold Tth, the CPU determines "yes" in step 715 and executes steps 720 to 730 sequentially.

[0171] Step 720: CPU performs acceleration limit control.

[0172] More specifically, the CPU obtains the accelerator pedal operation amount AP from the driver ECU30, and obtains the corresponding accelerator acceleration Gap. The accelerator acceleration Gap increases as the accelerator pedal operation amount AP increases.

[0173] If the accelerometer acceleration gap is greater than the specified limit acceleration Glmt, the CPU sets the target acceleration Gtgt to the limit acceleration Glmt. If the accelerometer acceleration gap is less than the limit acceleration Glmt, the CPU sets the target acceleration Gtgt to the accelerometer acceleration gap.

[0174] Step 725: The CPU sends acceleration / deceleration commands, including the target acceleration Gtgt, to the drive ECU30 and the brake ECU40.

[0175] Step 730: The CPU issues the first warning.

[0176] Then, the CPU proceeds to step 795, temporarily terminating this routine.

[0177] If the execution timer Texe is greater than the threshold Tth, the CPU determines "no" in step 715 and executes steps 735 to 745 in sequence.

[0178] Step 735: The CPU performs slow deceleration control.

[0179] More specifically, the CPU sets the target acceleration Gtgt to a specified negative acceleration Gsb.

[0180] Step 740: The CPU sends acceleration / deceleration commands, including the target acceleration Gtgt, to the drive ECU 30 and the brake ECU 40.

[0181] Step 745: The CPU issues the second warning.

[0182] Then, the CPU proceeds to step 795, temporarily terminating this routine.

[0183] As can be understood from the above, this auxiliary device 10 sets a threshold distance Dth that varies depending on the type of the object in front, thus reducing the possibility of performing unnecessary erroneous response controls.

[0184] The present invention is not limited to the above-described embodiments, and various modifications of the present invention may also be used.

[0185] (First variation)

[0186] In the above implementation, the CPU determines that the erroneous operation initiation condition is met if all three conditions are met (see reference). Figure 4 In this variant, the CPU determines that the erroneous operation initiation condition is met if the first condition is met and either the second or third condition is met.

[0187] It should be noted that, even if the first condition is not met, as long as at least one of the second and third conditions is met, the CPU will determine that the erroneous operation start condition is met.

[0188] (Second variation)

[0189] Alternatively, the CPU may determine that the recovery condition is met if at least one of the fourth condition, the fifth condition, and the sixth condition is met.

[0190] Fifth condition: The driver operates the brake pedal 42a for a specified time.

[0191] Sixth condition: The driver operates the cancel button (not shown).

[0192] (Third variation)

[0193] Alternatively, the CPU may determine whether the erroneous operation initiation condition is met only if the distance condition is met. More specifically, the CPU may execute the operation if it determines "yes" in step 625 because the distance D is below the threshold distance Dth. Figure 4 The error detection routine shown is executed as a subroutine, rather than being executed every specified time interval. Figure 4 The example shown is a misoperation detection routine. In this case, if the CPU determines "no" in step 670 (if there is no target in front at a distance D less than the threshold distance D), the value of the misoperation flag Xeo is set to "0".

[0194] (Fourth variation)

[0195] In the above implementation, the CPU performs acceleration limiting control and slow deceleration control as misoperation response control. However, the misoperation response control only needs to be at least acceleration limiting control, and may not include slow deceleration control.

[0196] (Fifth variation)

[0197] The camera device 23 can be a stereo camera or a monocular camera. The millimeter-wave radar device 24 can be a remote sensing device capable of detecting objects by transmitting wireless media other than millimeter waves and receiving reflected wireless media. Moreover, this auxiliary device 10 only needs to be able to correctly determine the position of the object relative to the vehicle VA based on the camera object information, and may not need to have the millimeter-wave radar device 24. In the absence of the millimeter-wave radar device 24, the image processing ECU 23a obtains the relative speed Vr based on the history of the position of the foreground object relative to the vehicle VA.

[0198] (Sixth variation)

[0199] This auxiliary device 10 can be installed in vehicles such as engine vehicles, hybrid electric vehicles (HEV), plug-in hybrid electric vehicles (PHEV), fuel cell electric vehicles (FCEV), and battery electric vehicles (BEV).

[0200] The present invention can also be understood as a non-temporary storage medium that stores a program for implementing the functions of the auxiliary device 10 and is readable by a computer.

Claims

1. A driving assistance device, comprising: An acceleration control element, operated by the driver of the vehicle, to increase the driving force generated by the vehicle's drive source; and The control unit is capable of performing acceleration limit control to ensure that the vehicle's acceleration does not exceed a predetermined limit. The control unit is configured to: Set different threshold distances based on the category of the forward object located in front of the vehicle. If both the distance condition and the specified misoperation condition are met, the acceleration limit control is executed, wherein... The distance condition is met when the distance between the vehicle and the target ahead is below the threshold distance, and the specified misoperation condition is met when the driver incorrectly operates the accelerator. In the presence of multiple forward targets, starting with the forward target that is closest to the vehicle, threshold distances corresponding to the category of each forward target are sequentially set, and it is determined whether the distance of the forward target is below the threshold distance. The distance condition is satisfied when there is a target in front at a distance that is below the threshold distance.

2. The driving assistance device according to claim 1, wherein, The control unit is configured to set the threshold distance shorter when the object ahead is classified as a vehicle, compared to when the object ahead is classified as a pedestrian.

3. The driving assistance device according to claim 1, wherein, The control unit is configured to: establish the misoperation condition from the time at least one of the conditions that the operation amount of the acceleration actuator is above a predetermined threshold operation amount and the condition that the operation speed of the acceleration actuator is above a predetermined threshold speed is met until a predetermined recovery condition that is met when the driver recovers from the erroneous operation of the acceleration actuator is met.

4. The driving assistance device according to claim 1, wherein, The control unit is configured to perform the acceleration limit control when the vehicle speed, which represents the speed of the vehicle, is below a predetermined threshold speed, and when the distance condition and the misoperation condition are met.

5. The driving assistance device according to claim 1, wherein, The control unit is configured to set the threshold distance longer the relative speed of the target object with respect to the vehicle.

6. A driving assistance method, comprising performing acceleration limit control such that the vehicle's acceleration does not exceed a predetermined limit acceleration, wherein, The driving assistance method includes: The first step is to set different threshold distances based on the category of the forward object located in front of the vehicle; The second step is to execute the acceleration limit control when the distance condition is met and the specified misoperation condition is met. The distance condition is met when the distance between the vehicle and the target in front is below the threshold distance. The specified misoperation condition is met when the driver of the vehicle erroneously operates an acceleration control device, which is an operation device operated by the driver to increase the driving force generated by the drive source of the vehicle. The third step, in the presence of multiple forward targets, involves sequentially setting threshold distances corresponding to the category of each forward target, starting with the forward target that is closest to the vehicle, and determining whether the distance to that forward target is below the threshold distance; and The fourth step is to ensure that the distance condition is met if there is a target in front at a distance that is below the threshold distance.

7. A computer program product, comprising a program that performs acceleration limit control to ensure that the acceleration of a vehicle does not exceed a predetermined limit acceleration, wherein... The program causes the computer in the vehicle to execute: The first step is to set different threshold distances based on the category of the forward object located in front of the vehicle; The second step is to execute the acceleration limit control when the distance condition is met and the specified misoperation condition is met. The distance condition is met when the distance between the vehicle and the target in front is below the threshold distance. The specified misoperation condition is met when the driver of the vehicle erroneously operates an acceleration control device, which is an operation device operated by the driver to increase the driving force generated by the drive source of the vehicle. The third step, in the presence of multiple forward targets, involves sequentially setting threshold distances corresponding to the category of each forward target, starting with the forward target that is closest to the vehicle, and determining whether the distance to that forward target is below the threshold distance; and The fourth step is to ensure that the distance condition is met if there is a target in front at a distance that is below the threshold distance.

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