Driving assistance device

Abstract

Provided is a driving assistance device capable of suppressing shake during execution of driving assistance and improving riding comfort for an occupant of a vehicle. A driving assistance device according to an embodiment performs driving assistance of a vehicle on the basis of peripheral information collected by a plurality of sensors provided in the vehicle, the driving assistance device being provided with: a route calculation unit that calculates a movement route of the vehicle to a target position on the basis of the peripheral information obtained from the plurality of sensors; a switching unit that switches the setting of the upper limit value of the acceleration of the vehicle between a first acceleration limit value and a second acceleration limit value smaller than the first acceleration limit value; and a movement control unit that controls the vehicle at an acceleration within the upper limit value set by the switching unit and moves the vehicle along the movement path, and when the vehicle is stopped and the steering angle of the vehicle is equal to or greater than a predetermined threshold value when the vehicle is controlled by the movement control unit, controls the vehicle at the acceleration within the upper limit value set by the switching unit. The switching unit sets the upper limit value of the acceleration of the vehicle to a second acceleration limit value.

Description

Technical Field

[0001] The present invention relates to a driving assistance device. Background Art

[0002] There is a driving assistance device that automatically parks and exits a vehicle in a parking area. During the driving assistance, an upper limit value of the acceleration of the vehicle is set, and the vehicle is controlled at an acceleration within the upper limit value.

[0003] For example, in the technology of Patent Document 1, the vehicle can be stopped at the target position by setting the time variation of the target value of acceleration when the vehicle decelerates, i.e., the acceleration curve, according to the distance to the target position. In addition, in the technology of Patent Document 2, the acceleration of the vehicle is limited to the acceleration within the upper limit set according to the speed of the vehicle, so that the occurrence of an unexpected acceleration state can be suppressed.

[0004] Patent Document 1: International Publication No. 2020 / 066331

[0005] Patent Document 2: Japanese Patent No. 5257647

[0006] However, if a stopped vehicle is started at a steering angle greater than a predetermined angle, the vehicle is prone to shaking even if the acceleration is controlled within the upper limit. Neither Patent Documents 1 nor Patent Documents 2 considers this point, and there is a fear that the shaking of the vehicle may deteriorate the riding comfort of passengers including the driver. Summary of the invention

[0007] The present invention has been made in view of the above circumstances, and provides a driving assistance device capable of suppressing shaking during driving assistance and improving the riding comfort of a vehicle occupant.

[0008] In order to solve the above-mentioned problems and achieve the purpose, a driving assistance device of an embodiment performs driving assistance for the vehicle based on surrounding information collected by multiple sensors installed in the vehicle, and the driving assistance device includes: a path calculation unit, which calculates a movement path of the vehicle to a target position based on the surrounding information obtained from the multiple sensors; a switching unit, which switches the setting of the upper limit value of the acceleration of the vehicle between a first acceleration limit value and a second acceleration limit value smaller than the first acceleration limit value; and a movement control unit, which controls the vehicle at an acceleration within the upper limit value set by the switching unit and moves the vehicle along the movement path, and when the vehicle is controlled by the movement control unit, when the vehicle stops and the steering angle of the vehicle becomes greater than a predetermined threshold value, the switching unit sets the upper limit value of the acceleration of the vehicle to the second acceleration limit value.

[0009] The driving assistance device according to the embodiment can suppress shaking during driving assistance and improve the riding comfort of the occupants of the vehicle. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] Figure 1 It is a plan view of a vehicle equipped with the driving assistance device according to the embodiment.

[0011] Figure 2 This is a block diagram showing an example of the overall configuration of a driving assistance system according to the embodiment.

[0012] Figure 3 This is a block diagram showing an example of a functional configuration of a driving assistance device according to an embodiment.

[0013] Figure 4 : is a graph showing an example of the setting of the acceleration limit value held by the driving assistance device according to the embodiment.

[0014] Figure 5 This is a flowchart showing an example of a procedure of a driving assistance process performed by the driving assistance device according to the embodiment.

[0015] Description of Reference Numerals

[0016] 10... vehicle; 14... distance measuring unit; 16... photographing unit; 20... driving assistance device; 200... driving assistance system; 201... display control unit; 202... acquisition unit; 203... detection unit; 204... path calculation unit; 205... switching unit; 206... movement control unit; 207... storage unit; LVd... default value; LFe... switching value. DETAILED DESCRIPTION

[0017] The same components in the following exemplary embodiments and the like are denoted by common reference numerals, and duplicate descriptions are omitted as appropriate.

[0018] (Example of vehicle structure)

[0019] Figure 1 It is a plan view of a vehicle 10 equipped with a driving assistance device 20 according to the embodiment. Figure 1 The front, rear, left, and right of the vehicle 10 in FIG. 1 represent directions when viewed from a driver's seat of the vehicle 10 .

[0020] The vehicle 10 of the embodiment may be, for example, an internal combustion engine vehicle using an internal combustion engine as a driving source, an electric vehicle or a fuel cell vehicle using an electric motor as a driving source, or a hybrid vehicle using both of them as driving sources.

[0021] In addition, the vehicle 10 can be equipped with various transmission devices and various systems, components and other devices required to drive the internal combustion engine or the electric motor. In addition, the installation method, number and layout of the devices related to the driving of the wheels 13 in the vehicle 10 can be set in various ways.

[0022] like Figure 1 As shown, the vehicle 10 includes a vehicle body 12, a plurality of wheels 13, a plurality of distance measuring units 14a to 14l, and a plurality of imaging units 16a to 16d. In addition, when it is not necessary to distinguish the distance measuring units 14a to 14l, only the distance measuring unit 14 is recorded. In addition, when it is not necessary to distinguish the imaging units 16a to 16d, only the imaging unit 16 is recorded. These distance measuring units 14a to 14l and the imaging units 16a to 16d are examples of sensors that collect information about the surroundings of the vehicle 10.

[0023] The vehicle body 12 constitutes a vehicle room for passengers to sit in. A plurality of wheels 13 , a plurality of distance measuring units 14 , and a plurality of imaging units 16 are mounted on the vehicle body 12 . Figure 1 In the example of FIG. 1 , the vehicle body 12 includes four wheels 13, twelve distance measuring units 14, and four imaging units 16. However, the number of distance measuring units 14 and imaging units 16 mounted on the vehicle body 12 is arbitrary.

[0024] The four wheels 13 are provided at the front, rear, left, and right of the vehicle body 12. The two front wheels 13 function as, for example, steering wheels, and the two rear wheels 13 function as, for example, drive wheels.

[0025] The distance measuring unit 14 is, for example, a sonar that is provided at the outer periphery of the vehicle 10, transmits sound waves such as ultrasonic waves as detection waves, and captures the detection waves reflected by objects such as obstacles existing around the vehicle 10. Alternatively, the distance measuring unit 14 may be a radar or millimeter wave radar that transmits detection waves such as lasers.

[0026] The distance measuring unit 14 collects surrounding information indicating the conditions around the vehicle 10 and outputs it to the driving assistance device 20. For example, the distance measuring unit 14 collects the response time, which is the time from the transmission of the detection wave to the reception of the detection wave, as surrounding information for specifying the distance between the object and the vehicle 10. The driving assistance device 20 can detect the presence or absence of obstacles and the like around the vehicle 10 and the distance to the obstacles based on the surrounding information collected by the distance measuring unit 14.

[0027] Furthermore, when the distance measuring unit 14 receives a plurality of detection waves reflected from a plurality of positions of the object with respect to one transmission of a detection wave, it may include only the response time of the earliest received detection wave in the surrounding information.

[0028] The distance measuring units 14a to 14d are provided at the front of the vehicle body 12. The distance measuring units 14b and 14c of the distance measuring units 14a to 14d are also called front sonars and are provided at the front end of the vehicle 10. The distance measuring units 14b and 14c detect objects in front of the vehicle 10 and collect peripheral information in front of the vehicle 10. In addition, the distance measuring units 14a and 14d are also called corner sonars and are provided at the corner portion of the front of the vehicle 10. The distance measuring units 14a and 14d detect objects outside the front of the vehicle 10 and collect peripheral information outside the front of the vehicle 10.

[0029] The distance measuring units 14e to 14h are provided at the rear of the vehicle body 12. The distance measuring units 14f and 14g of the distance measuring units 14e to 14h are also called rear sonars and are provided at the rear end of the vehicle 10. The distance measuring units 14f and 14g detect objects behind the vehicle 10 and collect peripheral information behind the vehicle 10. In addition, the distance measuring units 14e and 14h are also called corner sonars and are provided at the corners of the rear of the vehicle 10. The distance measuring units 14e and 14h detect objects outside the rear of the vehicle 10 and collect peripheral information outside the rear of the vehicle 10.

[0030] The distance measuring units 14i to 14l are also called side sonars, and are provided on the side of the vehicle body 12. The distance measuring units 14i and 14j of the distance measuring units 14i to 14l are provided on the side of the front of the vehicle 10. The distance measuring units 14k and 14l are provided on the side of the rear of the vehicle 10. The distance measuring units 14i to 14l detect objects on the side of the vehicle 10 and collect peripheral information on the side of the vehicle 10.

[0031] The imaging unit 16 is a digital camera having an imaging element such as a CCD (Charge Coupled Device) or a CIS (CMOS Image Sensor) built in. The imaging unit 16 generates a captured image including a moving image or a still image of a plurality of frame images captured at a predetermined frame rate.

[0032] The imaging unit 16 is provided at the outer periphery of the vehicle body 12 and each has a wide-angle lens or a fish-eye lens, and can capture, for example, a range of 140° to 190° in the horizontal direction. The optical axis of the imaging unit 16 is set to face obliquely downward.

[0033] Thus, the imaging unit 16 collects surrounding information obtained by imaging the surroundings of the vehicle 10 including the road surface and outputs it to the driving assistance device 20. The driving assistance device 20 can detect the presence or absence of obstacles and the like around the vehicle 10 and the positions of the obstacles based on the surrounding information collected by the imaging unit 16. In addition, the driving assistance device 20 can detect parking areas around the vehicle 10 and the positions of the parking areas based on the surrounding information collected by the imaging unit 16.

[0034] The imaging unit 16c is provided at the center of the front-to-back direction of the left end of the vehicle body 12, for example, the lower surface of the left rearview mirror. The imaging unit 16c collects the captured image obtained by capturing the lower left side of the vehicle 10 as the surrounding information. The imaging unit 16d is provided at the center of the front-to-back direction of the right end of the vehicle body 12, for example, the lower surface of the right rearview mirror. The imaging unit 16d collects the captured image obtained by capturing the surrounding area of ​​the lower right side of the vehicle 10 as the surrounding information.

[0035] The imaging unit 16a is provided at the center of the front end of the vehicle body 12 in the left-right direction, such as the front bumper. The imaging unit 16a collects the captured images obtained by capturing the front of the vehicle 10 as the surrounding information. The imaging unit 16b is provided at the center of the rear end of the vehicle body 12 in the left-right direction, such as the rear bumper. The imaging unit 16b collects the captured images obtained by capturing the rear of the vehicle 10 as the surrounding information.

[0036] (Configuration example of driving assistance system)

[0037] Figure 2 2 is a block diagram showing an example of the overall configuration of the driving assistance system 200 according to the embodiment. The driving assistance system 200 is mounted on the vehicle 10, for example, and performs driving assistance such as parking the vehicle 10 in a parking area or exiting the vehicle 10 from a parking area.

[0038] like Figure 2 As shown, the driving assistance system 200 includes a driving assistance device 20, a monitoring device 30, a braking system 40, an acceleration system 50, a steering system 60, a transmission system 70, a vehicle speed sensor 83, a distance measuring unit 14, and a camera 16. These components are connected in a manner that can transmit and receive information to each other through an in-vehicle network NT.

[0039] The in-vehicle network NT is configured by including, for example, CAN (Controller Area Network) and LIN (Local Interconnect Network), etc. The in-vehicle network NT may be included in a part of the driving support system 200 .

[0040] The driving assistance device 20 is configured as a microcomputer such as an ECU (Electronic Control Unit), and performs driving assistance for the vehicle 10 .

[0041] The driving support device 20 includes a CPU (Central Processing Unit) 21, a display control circuit 23, an SSD (Solid State Drive) 24, a ROM (Read Only Memory) 25, and a RAM (Random Access Memory) 26. The CPU 21, the ROM 25, and the RAM 26 may be integrated in the same package.

[0042] The CPU 21 is an example of a hardware processor, and reads out a program stored in a nonvolatile storage device such as the ROM 25 , and executes various calculation processes and controls according to the program.

[0043] The ROM 25 stores various programs and parameters necessary for executing the programs, etc. The RAM 26 temporarily stores various data used in calculations of the CPU 21. The SSD 24 is a rewritable nonvolatile storage device and maintains data even when the power of the driving support device 20 is turned off.

[0044] Among the calculation processes performed by the driving assistance device 20 , the display control circuit 23 mainly performs image processing of images acquired by the imaging unit 16 , data conversion of images for display displayed on a display unit 31 included in the monitoring device 30 and described later, and the like.

[0045] The brake system 40 includes a brake unit 41 , a brake control unit 42 , and a brake unit sensor 43 , and controls deceleration of the vehicle 10 .

[0046] The brake unit 41 is a device including, for example, a brake and a brake pedal, and decelerates the vehicle 10. The brake control unit 42 is, for example, a microcomputer having a hardware processor such as a CPU. The brake control unit 42 controls the brake unit 41 based on an instruction from the driving assistance device 20 to control the deceleration of the vehicle 10. The brake unit sensor 43 is, for example, a position sensor, and detects the position of the brake pedal included in the brake unit 41. The brake unit sensor 43 outputs the detected brake pedal position to the in-vehicle network NT.

[0047] The acceleration system 50 includes an acceleration unit 51 , an acceleration control unit 52 , and an acceleration unit sensor 53 , and controls acceleration of the vehicle 10 .

[0048] The acceleration unit 51 is a device including, for example, an accelerator pedal, and accelerates the vehicle 10. The acceleration control unit 52 is, for example, a microcomputer including a hardware processor such as a CPU. The acceleration control unit 52 controls the acceleration unit 51 based on an instruction from the driving assistance device 20, thereby controlling the acceleration of the vehicle 10. The acceleration unit sensor 53 is, for example, a position sensor, and detects the position of the accelerator pedal included in the acceleration unit 51. The acceleration unit sensor 53 outputs the detected position of the accelerator pedal to the in-vehicle network NT.

[0049] The steering system 60 includes a steering unit 61 , a steering control unit 62 , and a steering unit sensor 63 , and controls the traveling direction of the vehicle 10 .

[0050] The steering control unit 61 is a device including, for example, a steering wheel or a steering wheel, and steers the steering wheel of the vehicle 10 to steer the direction of travel of the vehicle 10. The steering control unit 62 is, for example, a microcomputer including a hardware processor such as a CPU. The steering control unit 62 controls the steering control unit 61 based on instructions from the driving assistance device 20 to control the direction of travel of the vehicle 10. The steering control unit sensor 63 is, for example, an angle sensor including a Hall element, and detects the rotation angle of the steering control unit 61, that is, the steering angle. The steering control unit sensor 63 outputs the detected steering angle of the steering control unit 61 to the in-vehicle network NT.

[0051] The transmission system 70 includes a transmission unit 71 , a transmission control unit 72 , and a transmission unit sensor 73 , and controls the transmission ratio of the vehicle 10 .

[0052] The speed change unit 71 is a device including a shift lever, etc., for example, and changes the speed ratio of the vehicle 10. The speed change control unit 72 is a microcomputer including a hardware processor such as a CPU, for example. The speed change control unit 72 controls the speed change unit 71 based on instructions from the driving assistance device 20 to control the speed ratio of the vehicle 10. The speed change unit sensor 73 is, for example, a position sensor, and detects the position of the shift lever included in the speed change unit 71. The speed change unit sensor 73 outputs the detected position of the shift lever to the in-vehicle network NT.

[0053] The vehicle speed sensor 83 has, for example, a Hall element provided near the wheel 13 of the vehicle 10, and detects the rotation amount or the rotation speed per unit time of the wheel 13. The vehicle speed sensor 83 outputs the number of wheel speed pulses indicating the detected rotation amount or rotation speed to the in-vehicle network NT as a sensor value for calculating the speed (vehicle speed) of the vehicle 10. The driving assistance device 20 can calculate the speed and movement amount of the vehicle 10 based on the sensor value obtained from the vehicle speed sensor 83.

[0054] The monitoring device 30 is installed on a dashboard or the like in the interior of the vehicle 10 , and includes a display unit 31 and an input unit 32 .

[0055] The display unit 31 is a display device such as a liquid crystal display (LCD) or an organic EL display (OELD). The display unit 31 displays images based on image data sent from the driving assistance device 20 and images receiving operation instructions for switching between automatic driving and manual driving.

[0056] The input unit 32 is, for example, a touch panel provided on the display screen of the display unit 31. The input unit 32 is configured to be able to see through the content displayed on the display screen of the display unit 31. Thus, the input unit 32 can allow the passenger to visually recognize the display content of the display unit 31.

[0057] The input unit 32 receives instructions input by the occupant touching a position corresponding to the display content of the display unit 31, and transmits the instructions to the driving support device 20 via the in-vehicle network NT. The input unit 32 is not limited to a touch panel, and may be a hard switch such as a push button.

[0058] Figure 3 2 is a block diagram showing an example of the functional structure of the driving assistance device 20 according to the embodiment. Figure 3 As shown, the driving assistance device 20 includes a display control unit 201 , an acquisition unit 202 , a detection unit 203 , a path calculation unit 204 , a switching unit 205 , a movement control unit 206 , and a storage unit 207 as functional units.

[0059] These functional units are realized by, for example, the CPU 21 reading a program stored in a storage device such as the ROM 25 and executing the program. Alternatively, they are realized by the display control circuit 23, SSD 24, ROM 25, RAM 26, etc. operating under the control of the CPU 21 according to the program.

[0060] Furthermore, part or all of these functional units may be configured by hardware such as a circuit including an ASIC (Application Specific Integrated Circuit).

[0061] The display control unit 201 generates content to be displayed on the display unit 31 of the monitoring device 30, and displays it on the display unit 31. In other words, the display control unit 201 displays, on the display unit 31, for example, a notification screen that a parking area where the vehicle 10 can park has been detected, a selection screen for starting, interrupting, or stopping driving assistance, and an image of the surroundings of the vehicle 10 during driving assistance.

[0062] The acquisition unit 202 acquires the transmission and reception information of the sound wave from the distance measuring unit 14 and acquires the captured image of the periphery of the vehicle 10 from the imaging unit 16 as the periphery information of the vehicle 10 .

[0063] The detection unit 203 detects obstacles, parking spaces, parking areas, and the like around the vehicle 10 based on the surrounding information acquired by the acquisition unit 202 .

[0064] Obstacles are various objects such as other vehicles, walls, pillars, fences, protrusions, steps, wheel chocks, etc. In addition, obstacles may be, for example, people walking in the parking lot.

[0065] The parking space is an area provided for parking the vehicle 10 and divided by, for example, a dividing line, a frame line, a straight line, a belt, a step, etc. The parking area is a parking space where the vehicle 10 can park, in other words, a parking space where there are no obstacles such as other vehicles that hinder the parking of the vehicle 10. The dividing line, frame line, straight line, belt, step, etc. mentioned above are examples of objects indicating the parking area, and when the driving assistance device 20 assists the vehicle 10 in entering or exiting the parking area, they become the target objects when the vehicle 10 enters or exits the parking area.

[0066] If there is an instruction to start driving assistance from the driver of the vehicle 10, the detection unit 203 detects the presence of an obstacle, the distance from the vehicle 10 to the obstacle, etc. based on the detection result of the distance measuring unit 14, for example. In addition, the detection unit 203 detects the presence of obstacles and parking spaces, as well as their positions (orientations) relative to the vehicle 10 and their shapes, sizes, heights, etc., by image processing based on images captured by the imaging unit 16, for example.

[0067] The detection unit 203 combines these detection results to extract information such as whether there are obstacles around the vehicle 10, whether the obstacles can hinder the driving of the vehicle 10, whether there are parking spaces around the vehicle 10, whether the vehicle 10 can be parked in the parking space, in other words, whether it can be used as a parking area.

[0068] The path calculation unit 204 calculates a target position for guiding the vehicle 10 based on the detection result of the detection unit 203 , and calculates a movement path for moving the vehicle 10 to the target position.

[0069] If the vehicle 10 is parked, the parking area detected by the detection unit 203 becomes the target position. If the vehicle 10 is driven away, a predetermined place such as an aisle between a plurality of parking spaces where the vehicle 10 can start to drive safely becomes the target position.

[0070] In addition, the path calculation unit 204 may calculate the turning position as needed. In a case where it is difficult to park or move the vehicle in one reverse or forward motion, one or more turning positions are set.

[0071] The path calculation unit 204 calculates the movement path of the vehicle 10 from the current position of the vehicle 10 to the target position in order to guide the vehicle 10 to the target position calculated as described above. The movement path may also include a turning position as described above. In this case, the path calculation unit 204 calculates the movement path from the current position of the vehicle 10 to the target position via the turning position.

[0072] Thus, the movement path for parking such as reverse parking or forward parking is calculated by the path calculation unit 204. In addition, the movement path for exiting the vehicle such as forward exiting or backward exiting is calculated by the path calculation unit 204.

[0073] The movement control unit 206 controls various parts of the vehicle 10 to move the vehicle 10 during driving assistance of the vehicle 10. Specifically, the movement control unit 206 moves the vehicle 10 to the target position according to the above-mentioned movement path by controlling all or part of the brake system 40, the acceleration system 50, the steering system 60, and the transmission system 70. At this time, the movement control unit 206 moves the vehicle 10 while receiving feedback from various sensors such as the brake sensor 43, the acceleration sensor 53, the steering sensor 63, the transmission sensor 73, and the vehicle speed sensor 83.

[0074] In addition, after the movement control unit 206 starts the movement of the vehicle 10, the detection unit 203 continues to obtain the surrounding information from the distance measuring unit 14 and the imaging unit 16. The above-mentioned path calculation unit 204 appropriately recalculates the movement path based on the detection result of the detection unit 203. The movement control unit 206 continues the movement of the vehicle 10 in such a way that if the movement path is recalculated, the position of the vehicle 10 is finely adjusted accordingly.

[0075] When the movement control unit 206 controls the vehicle 10, the switching unit 205 appropriately switches the acceleration limit value that becomes the upper limit value of the acceleration of the vehicle 10. As the acceleration limit value in driving assistance, for example, a default value set when driving assistance is started and a switching value applied when the steering angle of the vehicle 10 becomes greater than a predetermined threshold value when the vehicle 10 is stopped are set. The details of these acceleration limit values ​​will be described later.

[0076] These acceleration limit values ​​are stored in, for example, the storage unit 207. The switching unit 205 switches these acceleration limit values ​​by referring to the storage unit 207 under a predetermined condition.

[0077] The movement control unit 206 sets a target speed corresponding to the status of the vehicle 10 at each time, and controls the vehicle 10 to accelerate at an acceleration within the acceleration limit value determined by the switching unit 205 so that the speed of the vehicle 10 reaches the target speed.

[0078] The storage unit 207 stores, for example, programs executed by the CPU 21 of the driving assistance device 20 and various control parameters required for the operation of the driving assistance device 20. In addition, the storage unit 207 stores settings such as the above-mentioned various acceleration limit values ​​that serve as upper limits of the acceleration of the vehicle 10 during driving assistance as described above.

[0079] Figure 4 An example of setting the above-mentioned acceleration limit value is shown. Figure 4 : is a graph showing an example of the setting of the acceleration limit value held by the driving assistance device 20 according to the embodiment. Figure 4 The horizontal axis of the coordinate graph is time (s), and the vertical axis is target speed (m / s).

[0080] like Figure 4 As shown, the switching value LFe applied under the above-mentioned predetermined condition is set to a value smaller than the default value LVd set normally among the acceleration limit values ​​held by the driving assistance device 20. Therefore, if the target speed of the vehicle 10 is the same, when the switching value LFe is applied, it takes longer time to reach the target speed than when the default value LVd is set.

[0081] The state in which the steering angle is equal to or greater than a predetermined threshold value by operating the steering wheel while the vehicle 10 is stopped is called a so-called stationary steering state. In the stationary steering state, the vehicle 10 is likely to shake when starting.

[0082] In driving assistance, as a principle, the vehicle 10 is controlled while avoiding the stationary steering state, but the stationary steering control may be performed in a case where there is very little free space around the vehicle 10. When the vehicle 10 is in the stationary steering state, the switching value LFe that is smaller than the default value LVd is used as the acceleration limit value to suppress the shaking of the vehicle 10.

[0083] In this way, in driving assistance, the vehicle 10 is controlled in a state where only the default value LVd is set. Such a default value LVd can also be said to be an initial value or a standard value of the acceleration limit value. On the other hand, in this specification, the switching value LFe applied when the vehicle 10 is in the stationary steering state is sometimes referred to as the acceleration limit value when the stationary steering is performed.

[0084] Among these acceleration limit values, the default value LVd is an example of the first acceleration limit value, and the switching value LFe is an example of the second acceleration limit value.

[0085] (Processing Example of Driving Assistance Device)

[0086] Next, use Figure 5 An example of driving assistance processing performed by the driving assistance device 20 according to the embodiment will be described. Figure 5 1 is a flowchart showing an example of a procedure of a driving assistance process performed by the driving assistance device 20 according to the embodiment.

[0087] like Figure 5 As shown in FIG. 1 , when an instruction to start driving assistance is received from the driver of the vehicle 10 or the like, control by the driving assistance device 20 is started (step S101). The path calculation unit 204 calculates the moving path of the vehicle 10 from the parking position to the target position at that moment (step S102). When driving assistance is started, the switching unit 205 sets the default value LVd as the acceleration limit value (step S103).

[0088] The switching unit 205 is based on, for example, the vehicle speed sensor 83 (see Figure 2 ) and the like, and determines whether the vehicle 10 is in a stopped state (step S104). When the vehicle 10 is in a stopped state (step S104: Yes), the switching unit 205 determines whether the vehicle 10 is in a stopped state based on, for example, the steering sensor 63 (see Figure 2 ) etc., to determine whether the steering angle of the vehicle 10 is above a predetermined threshold value (step S105).

[0089] When the steering angle is equal to or greater than the predetermined threshold value (step S105 : Yes), the switching unit 205 switches the acceleration limit value of the vehicle 10 from the default value LVd set in the process of step 103 when the driving assistance is just started to the switching value LFe (step S106 ).

[0090] When the switching value LVer is set as the acceleration limit value, the movement control unit 206 accelerates the vehicle 10 to the target speed at the acceleration within the switching value LVer, and performs movement control of the vehicle 10 according to the calculated movement path (step S107 ).

[0091] When the movement control of the vehicle 10 is started, the switching unit 205 determines whether the steering angle is less than a predetermined value (step S109). While the steering angle is maintained at or above a predetermined threshold value (step S109: No), the switching unit 205 continues to monitor the steering angle.

[0092] If the steering wheel is operated in the stopped state, etc., and the vehicle 10 starts to move when the steering angle becomes greater than a predetermined threshold, the stationary steering state is eliminated and the steering angle is less than the predetermined threshold. Therefore, if the steering angle is less than the predetermined value (step S109: Yes), the switching unit 205 restores the setting of the acceleration limit value to the original default value LVd (step S110). In other words, the acceleration limit value in the stationary steering state is released by the processing of step S110.

[0093] If the vehicle 10 is not stopped (step S104: No) or the steering angle is less than the predetermined threshold value (step S105: No), the process of step S106 is not performed and the initially set default value LVd is maintained as the acceleration limit value.

[0094] The movement control unit 206 accelerates the vehicle 10 to the target speed at an acceleration within the default value LVd, and performs movement control of the vehicle 10 according to the calculated movement path (step S108 ).

[0095] Furthermore, the movement control unit 206 determines whether the driving assistance process is terminated, such as when the vehicle 10 reaches the target position (step S111). If the driving assistance process is continuing (step S111: No), the process from step S104 is repeated until the driving assistance process is terminated (step S111: Yes).

[0096] Based on the above, the driving assistance process performed by the driving assistance device 20 according to the embodiment ends.

[0097] (Summary)

[0098] The driving assistance device assists the driving of the vehicle based on the surrounding information of the vehicle obtained from various sensors such as the distance measuring unit and the imaging unit. In this case, when the parking space is extremely small, the vehicle 10 is controlled to start in a stationary state. However, when starting in a stationary state, the vehicle 10 may be easily shaken, which may cause the occupants of the vehicle including the driver to feel that the riding comfort is deteriorated.

[0099] According to the driving assistance device 20 of the embodiment, when the vehicle 10 is controlled by the movement control unit 206, when the vehicle 10 is stopped and the steering angle of the vehicle 10 is equal to or greater than a predetermined threshold value, the acceleration limit value, which is the upper limit value of the acceleration of the vehicle 10, is set to the switching value LFe. This can suppress the shaking of the vehicle 10 when starting in a stationary steering state, and improve the riding comfort of the occupants of the vehicle 10 including the driver.

[0100] According to the driving assistance device 20 of the embodiment, when driving assistance is started, the acceleration limit value of the vehicle 10 is set to the default value LVd. In this way, by preparing the default value LVd having a larger value than the switching value LFe separately, the vehicle 10 can reach the target speed with appropriate acceleration, and the unnecessary time required for parking or leaving the vehicle can be reduced and the processing can be quickly ended.

[0101] According to the driving assistance device 20 of the embodiment, after the acceleration limit value of the vehicle 10 is set to the switching value LFe, if the steering angle is less than the above threshold, the acceleration limit value is switched to the default value LVd. In this way, by applying the switching value LFe, which is smaller than the default value LVd, only during the period when the vehicle 10 is in the stationary steering state, the riding comfort of the occupants can be improved, and the unnecessary time required for parking or leaving the vehicle can be suppressed, and the processing can be quickly ended.

[0102] In addition, in the above-mentioned embodiment, the driving assistance device 20 is mounted on the vehicle 10, but the driving assistance device 20 may not necessarily be mounted on the vehicle 10. For example, the driving assistance device may acquire the surrounding information of the vehicle from various sensors at a position away from the vehicle and perform driving assistance of the vehicle through remote operation.

Claims

1. A driving assistance device for assisting the driving of a vehicle based on surrounding information collected by a plurality of sensors installed in the vehicle. The driving assistance device is characterized by comprising: a path calculation unit that calculates a movement path of the vehicle to a target position based on the surrounding information obtained from the plurality of sensors; a switching unit that switches the setting of the upper limit value of the acceleration of the vehicle between a first acceleration limit value and a second acceleration limit value that is smaller than the first acceleration limit value; and a movement control unit configured to control the vehicle at an acceleration within an upper limit value set by the switching unit and to move the vehicle along the movement path, When the vehicle is controlled by the movement control unit, the switching unit sets an upper limit value of the acceleration of the vehicle to the second acceleration limit value when the vehicle is stopped and a steering angle of the vehicle is equal to or greater than a predetermined threshold value.

2. The driving assistance device according to claim 1, characterized in that: When the driving assistance is started, the switching unit sets an upper limit value of the acceleration of the vehicle to the first acceleration limit value.

3. The driving assistance device according to claim 1 or 2, characterized in that: The switching unit switches the upper limit value of the acceleration of the vehicle to the first acceleration limit value if the steering angle is less than the threshold value after setting the upper limit value of the acceleration of the vehicle to the second acceleration limit value.

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