Parking Assistance Device

Abstract

This parking assistance device is provided with: a route setting unit for setting a movement route for a vehicle; and a control unit for controlling the vehicle by changing the acceleration in accordance with the distance between a starting position of the vehicle in the movement route and a stopping position of the vehicle in the movement route.

Description

[Technical field]

[0001] An embodiment of the present invention relates to a parking assistance device. [Background technology]

[0002] Conventionally, there is known a parking assistance device that controls a vehicle to park the vehicle in a parking area. The parking assistance device calculates a movement path to a target position and steers the vehicle according to the movement path to guide the vehicle to the target position. In addition, there is known a parking assistance device that performs brake control and acceleration / deceleration control in addition to steering control when guiding the vehicle to the target position. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent Publication No. 2021-62743 [Patent Document 2] JP 2019-107938 A Summary of the Invention [Problem to be solved by the invention]

[0004] In parking assistance, it is beneficial if the vehicle can be controlled with high precision.

[0005] Therefore, one of the objectives of the embodiment of the present invention is to obtain a parking assistance device that can improve the accuracy of vehicle control, for example. [Means for solving the problem]

[0006] The parking assistance device of the embodiment includes a route setting unit that sets a route for a vehicle to travel, and a control unit that controls the vehicle by changing acceleration according to the distance between a starting position of the vehicle on the route and a stopping position of the vehicle on the route.

[0007] According to such a configuration, the vehicle is controlled by changing the acceleration according to the distance between the vehicle's starting position on the travel route and the vehicle's stopping position on the travel route, thereby improving the accuracy of vehicle control (e.g., control of the vehicle's stopping position and vehicle speed) compared to a configuration in which the acceleration is not changed according to the distance.

[0008] In the parking assistance device, for example, the control unit performs braking control of the vehicle using a plurality of decelerations that are set to become smaller as the distance between the starting position and the stopping position becomes shorter.

[0009] According to such a configuration, for example, the vehicle is braked using a plurality of decelerations that are set to be smaller as the distance between the starting position of the vehicle on the travel route and the stopping position of the vehicle on the travel route becomes shorter, so that the timing of braking start becomes earlier as the distance becomes shorter. Therefore, even if the distance is short, the time from the start of braking to the stop of the vehicle can be extended, so that the vehicle can be braked accurately during that time. Therefore, the stopping position accuracy can be improved.

[0010] In the parking assistance device, for example, the multiple decelerations are a first deceleration when the distance is equal to or greater than a threshold value and a second deceleration when the distance is less than the threshold value, and the second deceleration is smaller than the first deceleration.

[0011] According to this configuration, the multiple decelerations are the first deceleration and the second deceleration, so that it is possible to suppress the complexity of the braking control.

[0012] In the parking assistance device, for example, when the distance is less than a threshold value, the control unit starts a deceleration operation at an earlier timing than when the distance is equal to or greater than the threshold value.

[0013] With this configuration, braking control can be performed with even greater precision when the distance is less than the threshold value.

[0014] The parking assistance device, for example, includes a target speed setting unit that sets a target speed between the starting position and the stopping position, and the control unit increases the driving force of the vehicle at a first rate of change when the vehicle starts when the distance between the starting position and the stopping position is less than a distance threshold, increases the driving force of the vehicle at a second rate of change greater than the first rate of change when the vehicle starts when the distance is equal to or greater than the distance threshold and the target speed is equal to or greater than a speed threshold, and increases the driving force at the first rate of change when the distance is equal to or greater than the distance threshold and the target speed is less than the speed threshold.

[0015] According to this configuration, when the distance is equal to or greater than the distance threshold and the target speed is less than the speed threshold, the control unit increases the driving force at the first rate of change, which makes it easier to control the vehicle speed compared to a configuration in which the driving force is increased at the second rate of change in this case, thereby improving the accuracy of the vehicle speed.

[0016] In the parking assistance device, for example, the control unit reduces the braking force of the vehicle at a third change rate when the vehicle starts when the distance is less than the distance threshold, reduces the braking force at a fourth change rate greater than the third change rate when the vehicle starts when the distance is equal to or greater than the distance threshold and the target speed is equal to or greater than the speed threshold, and reduces the braking force at the third change rate when the distance is equal to or greater than the distance threshold and the target speed is less than the speed threshold.

[0017] According to this configuration, when the distance is equal to or greater than the distance threshold and the target speed is less than the speed threshold, the control unit reduces the braking force at the third rate of change, which makes it easier to control the vehicle speed compared to a configuration in which the driving force is increased at the fourth rate of change in this case, thereby improving the accuracy of the vehicle speed. [Brief description of the drawings]

[0018] [Figure 1] FIG. 1 is an exemplary perspective view showing a state in which a part of a vehicle interior of a vehicle according to a first embodiment is seen through. [Diagram 2]FIG. 2 is an exemplary plan view (bird's-eye view) of the vehicle according to the first embodiment. [Diagram 3] FIG. 3 is an exemplary block diagram of the configuration of the parking assistance system according to the first embodiment. [Figure 4] FIG. 4 is an exemplary block diagram of a partial configuration of the ECU (parking assistance device) of the parking assistance system according to the first embodiment. [Diagram 5] FIG. 5 is a flowchart showing an example of a procedure of a process performed by the parking assistance device of the first embodiment. [Figure 6] FIG. 6 is an exemplary schematic plan view showing an initial position of the vehicle, a route, and a target position when the target position is set corresponding to a parking space by the parking assistance device of the first embodiment. [Figure 7] FIG. 7 is a diagram showing the time course of the vehicle speed when the first deceleration is used in the braking control of the parking assistance system of the first embodiment. [Figure 8] FIG. 8 is a diagram showing the time course of the vehicle speed when the second deceleration is used in the braking control of the parking assistant system of the first embodiment. [Figure 9] FIG. 9 is a flowchart showing an example of a procedure of a braking process performed by the parking assistance device of the first embodiment. [Figure 10] FIG. 10 is a diagram for explaining the deceleration used in the parking assistance device of the first modified example of the first embodiment. [Figure 11] FIG. 11 is an exemplary block diagram of a partial configuration of an ECU (parking assistance device) of the parking assistance system according to the second embodiment. [Figure 12] FIG. 12 is a flowchart showing an example of a procedure of a process performed by the parking assistance device of the second embodiment. [Figure 13] FIG. 13 is a flowchart showing an example of a procedure of a starting process performed by the parking assistance device of the second embodiment. [Figure 14] FIG. 14 is a diagram showing an example of the relationship between the driving force and the braking force and the elapsed time in the starting process by the parking assistance device of the second embodiment. [Figure 15] FIG. 15 is a flowchart showing an example of a procedure of a starting process performed by the parking assistance device of the first modified example of the second embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0019] Exemplary embodiments of the present invention are disclosed below. The configurations of the embodiments described below, as well as the actions, results, and effects brought about by the configurations, are merely examples. The present invention can be realized with configurations other than those disclosed in the following embodiments, and it is possible to obtain at least one of various effects based on the basic configuration and derivative effects.

[0020] <First embodiment> FIG. 1 is an exemplary perspective view showing a state in which a part of the cabin of the vehicle of the first embodiment is seen through. The vehicle 1 of this embodiment may be, for example, an automobile using an internal combustion engine (not shown) as a drive source, i.e., an internal combustion engine automobile, an automobile using an electric motor (not shown) as a drive source, i.e., an electric automobile or a fuel cell automobile, a hybrid automobile using both of them as drive sources, or an automobile equipped with other drive sources. In addition, the vehicle 1 may be equipped with various transmissions, and may be equipped with various devices, such as systems and parts, required for driving the internal combustion engine and the electric motor. In addition, the type, number, layout, etc. of the device related to the drive of the wheels 3 in the vehicle 1 may be set in various ways.

[0021] As illustrated in FIG. 1, the vehicle body 2 forms a vehicle compartment 2a in which an occupant (not shown) rides. In the vehicle compartment 2a, a steering unit 4, an acceleration operation unit 5, a braking operation unit 6, a gear shift operation unit 7, and the like are provided in a state facing a driver's seat 2b as an occupant. The steering unit 4 is, for example, a steering wheel protruding from a dashboard 24, the acceleration operation unit 5 is, for example, an accelerator pedal positioned under the driver's feet, the braking operation unit 6 is, for example, a brake pedal positioned under the driver's feet, and the gear shift operation unit 7 is, for example, a shift lever protruding from a center console. Note that the steering unit 4, the acceleration operation unit 5, the braking operation unit 6, the gear shift operation unit 7, and the like are not limited to these.

[0022] In addition, a display device 8 as a display output unit and an audio output device 9 as an audio output unit are provided in the vehicle interior 2a. The display device 8 is, for example, an LCD (liquid crystal display) or an OELD (organic electroluminescent display). The audio output device 9 is, for example, a speaker. The display device 8 is covered with a transparent operation input unit 10 such as a touch panel. The passenger can visually recognize an image displayed on the display screen of the display device 8 through the operation input unit 10. The passenger can perform operation input by touching, pressing, or moving the operation input unit 10 with a finger or the like at a position corresponding to the image displayed on the display screen of the display device 8. The display device 8, the audio output device 9, the operation input unit 10, etc. are provided in a monitor device 11 located, for example, in the center of the dashboard 24 in the vehicle width direction, i.e., the left-right direction. The monitor device 11 can have an operation input unit (not shown) such as a switch, a dial, a joystick, or a push button. Also, an audio output device (not shown) may be provided at a position in the vehicle interior 2a different from the monitor device 11, and audio may be output from the audio output device 9 of the monitor device 11 and another audio output device. The monitor device 11 may also be used as, for example, a navigation system or an audio system.

[0023] FIG. 2 is an exemplary plan view (bird's-eye view) of the vehicle of the first embodiment. As illustrated in FIGS. 1 and 2, the vehicle 1 is, for example, a four-wheeled vehicle, and has two front wheels 3F, one on the left and one on the right, and two rear wheels 3R, one on the left and one on the right. All of these four wheels 3 can be configured to be steerable. As illustrated in FIG. 3, the vehicle 1 has a steering system 13 that steers at least two wheels 3. The steering system 13 has an actuator 13a and a torque sensor 13b. The steering system 13 is electrically controlled by an ECU 14 (electronic control unit) or the like to operate the actuator 13a. The steering system 13 is, for example, an electric power steering system or a steer-by-wire (SBW) system. The steering system 13 supplements the steering force by adding torque, i.e., assist torque, to the steering unit 4 by the actuator 13a, and steers the wheels 3 by the actuator 13a. In this case, the actuator 13a may steer one wheel 3 or may steer a plurality of wheels 3. Furthermore, the torque sensor 13b detects the torque applied to the steering unit 4 by the driver, for example.

[0024] As illustrated in FIG. 2, the vehicle body 2 is provided with a plurality of imaging units 15, such as four imaging units 15a to 15d. The imaging units 15 are digital cameras incorporating imaging elements such as a charge coupled device (CCD) or a CMOS image sensor (CIS). The imaging units 15 can output video data at a predetermined frame rate. The imaging units 15 each have a wide-angle lens or a fisheye lens, and can capture an image in a range of, for example, 140° to 190° in the horizontal direction. The optical axis of the imaging unit 15 is set to face diagonally downward. Thus, the imaging unit 15 sequentially captures the external environment around the vehicle body 2, including the road surface on which the vehicle 1 can move and the area in which the vehicle 1 can be parked, and outputs the captured image data.

[0025] The imaging unit 15a is located, for example, at the rear end 2e of the vehicle body 2 and is provided on a wall below the door 2h of the rear trunk. The imaging unit 15b is located, for example, at the right end 2f of the vehicle body 2 and is provided on the right door mirror 2g. The imaging unit 15c is located, for example, at the front end 2c of the vehicle body 2, i.e., the front side in the vehicle longitudinal direction, and is provided on the front bumper or the like. The imaging unit 15d is located, for example, at the left end 2d of the vehicle body 2, i.e., the left end in the vehicle width direction, and is provided on the door mirror 2g as a left protrusion. The ECU 14 executes arithmetic processing and image processing based on the image data obtained by the multiple imaging units 15, and can generate an image with a wider viewing angle or generate a virtual overhead image of the vehicle 1 viewed from above. The overhead image can also be called a planar image.

[0026] Furthermore, the ECU 14 identifies, from the image captured by the imaging unit 15, demarcation lines or the like marked on the road surface around the vehicle 1, and detects (extracts) parking spaces marked by the demarcation lines or the like.

[0027] As illustrated in FIGS. 1 and 2, the vehicle body 2 is provided with a plurality of distance measuring units 16, 17, for example, four distance measuring units 16a to 16d and eight distance measuring units 17a to 17h. The distance measuring units 16, 17 are, for example, sonars that emit ultrasonic waves and capture the reflected waves. The sonars may also be called sonar sensors or ultrasonic detectors. The ECU 14 can measure the presence or absence of objects such as obstacles positioned around the vehicle 1 and the distance to the objects based on the detection results of the distance measuring units 16, 17. That is, the distance measuring units 16, 17 are an example of a detection unit that detects objects. The distance measuring unit 17 may be used, for example, to detect objects at a relatively short distance, and the distance measuring unit 16 may be used, for example, to detect objects at a relatively long distance that are farther away than the distance measuring unit 17. The distance measuring unit 17 may be used, for example, to detect objects in front of and behind the vehicle 1, and the distance measuring unit 16 may be used to detect objects on the sides of the vehicle 1. Furthermore, the distance measuring units 16 and 17 may be radar devices or the like.

[0028] FIG. 3 is an exemplary block diagram of the configuration of the parking assistance system of the first embodiment. As illustrated in FIG. 3, in the parking assistance system 100, the ECU 14, the monitor device 11, the steering system 13, the distance measuring units 16 and 17, the brake system 18, the steering angle sensor 19, the accelerator sensor 20, the shift sensor 21, the wheel speed sensor 22, and the like are electrically connected via an in-vehicle network 23 as an electric communication line. The in-vehicle network 23 is configured as, for example, a CAN (controller area network). The ECU 14 can control the steering system 13, the brake system 18, and the like by sending control signals via the in-vehicle network 23. In addition, the ECU 14 can receive detection results of the torque sensor 13b, the brake sensor 18b, the steering angle sensor 19, the distance measuring unit 16, the distance measuring unit 17, the accelerator sensor 20, the shift sensor 21, the wheel speed sensor 22, and the like, as well as operation signals of the operation input unit 10, and the like, via the in-vehicle network 23.

[0029] The ECU 14 includes, for example, a central processing unit (CPU) 14a, a read only memory (ROM) 14b, a random access memory (RAM) 14c, a display control unit 14d, a sound control unit 14e, and a solid state drive (SSD) 14f (flash memory). The CPU 14a can execute various arithmetic processing and control, such as image processing related to an image displayed on the display device 8, determination of a target position of the vehicle 1, calculation of a moving path of the vehicle 1, determination of the presence or absence of interference with an object, automatic control of the vehicle 1, and cancellation of automatic control. The CPU 14a can read out a program installed and stored in a non-volatile storage device such as the ROM 14b, and execute arithmetic processing according to the program. The RAM 14c temporarily stores various data used in the calculations in the CPU 14a. The display control unit 14d mainly executes image processing using image data obtained by the imaging unit 15 and composition of image data displayed on the display device 8, among the arithmetic processing in the ECU 14. Among the arithmetic processing in the ECU 14, the voice control unit 14e mainly processes the voice data output by the voice output device 9. The SSD 14f is a rewritable non-volatile storage unit, and can store data even when the power supply of the ECU 14 is turned off. The CPU 14a, the ROM 14b, the RAM 14c, and the like can be integrated in the same package. The ECU 14 may be configured to use other logic operation processors such as a DSP (digital signal processor) or logic circuits instead of the CPU 14a. A hard disk drive (HDD) may be provided instead of the SSD 14f, or the SSD 14f and the HDD may be provided separately from the ECU 14. The ECU 14 is an example of a parking assistance device.

[0030] The brake system 18 is, for example, an anti-lock brake system (ABS) that suppresses locking of the brakes, an electronic stability control (ESC) that suppresses skidding of the vehicle 1 when cornering, an electric brake system that enhances the braking force (performs brake assist), a brake by wire (BBW), etc. The brake system 18 applies a braking force to the wheels 3 and thus the vehicle 1 via an actuator 18a. The brake system 18 can also detect brake lock, freewheeling of the wheels 3, signs of skidding, etc. from the rotation difference between the left and right wheels 3, and execute various controls. The brake sensor 18b is, for example, a sensor that detects the position of a movable part of the brake operating unit 6. The brake sensor 18b can detect the position of a brake pedal as a movable part. The brake sensor 18b includes a displacement sensor.

[0031] The steering angle sensor 19 is a sensor that detects the amount of steering of the steering unit 4, such as a steering wheel. The steering angle sensor 19 is configured using, for example, a Hall element. The ECU 14 acquires the amount of steering of the steering unit 4 by the driver and the amount of steering of each wheel 3 during automatic steering from the steering angle sensor 19 and executes various controls. The steering angle sensor 19 detects the rotation angle of a rotating part included in the steering unit 4. The steering angle sensor 19 is an example of an angle sensor.

[0032] The accelerator sensor 20 is, for example, a sensor that detects the position of a movable part of the acceleration operating unit 5. The accelerator sensor 20 can detect the position of an accelerator pedal as a movable part. The accelerator sensor 20 includes a displacement sensor.

[0033] The shift sensor 21 is, for example, a sensor that detects the position of a movable part of the gear shift operation unit 7. The shift sensor 21 can detect the position of a movable part such as a lever, an arm, a button, etc. The shift sensor 21 may include a displacement sensor, or may be configured as a switch.

[0034] The wheel speed sensor 22 is a sensor that detects the amount of rotation of the wheel 3 and the number of rotations per unit time. The wheel speed sensor 22 outputs the number of wheel speed pulses indicating the detected number of rotations as a sensor value. The wheel speed sensor 22 can be configured using, for example, a Hall element. The ECU 14 calculates the amount of movement of the vehicle 1 and the like based on the sensor value acquired from the wheel speed sensor 22, and executes various controls. Note that the wheel speed sensor 22 may be provided in the brake system 18. In that case, the ECU 14 acquires the detection result of the wheel speed sensor 22 via the brake system 18.

[0035] The configurations, arrangements, electrical connection forms, and the like of the various sensors and actuators described above are merely examples, and can be set (changed) in various ways.

[0036] FIG. 4 is an exemplary block diagram of a part of the configuration of the ECU (parking assistance device) of the parking assistance system of the first embodiment. As shown in FIG. 4, the ECU 14 includes an acquisition unit 141, an obstacle detection unit 142, a parking space detection unit 143, a display position determination unit 144, a target position determination unit 145, an output information control unit 146, a route setting unit 147, a guidance control unit 148, a storage unit 149, and the like. The CPU 14a executes processing according to a program, thereby functioning as the acquisition unit 141, the obstacle detection unit 142, the parking space detection unit 143, the display position determination unit 144, the target position determination unit 145, the output information control unit 146, the route setting unit 147, the guidance control unit 148, and the like. The storage unit 149 stores data used in the arithmetic processing of each unit, data of the result of the arithmetic processing, and the like. At least a part of the functions of each unit may be realized by hardware.

[0037] The acquisition unit 141 acquires various data, signals, etc. The acquisition unit 141 acquires data, signals, etc., such as detection results of each sensor, operation input, instruction input, image data, etc. The acquisition unit 141 can acquire signals due to operation input of the operation unit 14g. The operation unit 14g is, for example, a push button, a switch, etc.

[0038] The obstacle detection unit 142 detects an obstacle that interferes with the travel of the vehicle 1. The obstacle may be, for example, another vehicle, a wall, a pillar, a fence, a protrusion, a step, a wheel stopper, an object, or the like. The obstacle detection unit 142 can detect the presence or absence, height, size, and the like of an obstacle by various methods. The obstacle detection unit 142 can detect an obstacle based on, for example, the detection results of the distance measurement units 16 and 17. Alternatively, the obstacle detection unit 142 may detect the height of an obstacle based on the detection results of the distance measurement units 16 and 17 and the height of each beam. The obstacle detection unit 142 may detect the presence or absence or the height of an obstacle based on the detection results of the wheel speed sensor 22 or an acceleration sensor (not shown) and the detection results of the distance measurement units 16 and 17. In addition, the obstacle detection unit 142 may detect the height of an obstacle by, for example, image processing based on an image captured by the imaging unit 15.

[0039] The parking space detection unit 143 detects parking spaces provided as signs or objects. A parking space is a space that is set as a guideline or reference for parking the vehicle 1 in that location. A parking boundary (boundary) is a boundary or outer edge of a parking space, such as a partition line, a frame line, a straight line, a strip, a step, or the edges thereof. In other words, a parking boundary is a sign or an object. The parking space detection unit 143 can detect a parking space and a parking boundary by, for example, image processing based on an image captured by the imaging unit 15. The parking space detection unit 143 is an example of a boundary detection unit.

[0040] The display position determination unit 144 determines the display position of a display element that serves as a guide or target for guiding the vehicle 1 based on, for example, at least one of the detection result by the obstacle detection unit 142 and the detection result by the parking space detection unit 143. The display position may correspond to an end point of the movement route or may correspond to a position along the movement route. The display element may be set as, for example, a point, a line, a frame, an area, or the like displayed on the display device 8.

[0041] The target position determination unit 145 determines a target position as a guide or target position for guiding the vehicle 1 based on, for example, at least one of the detection result by the obstacle detection unit 142 and the detection result by the parking space detection unit 143. The target position may correspond to an end point of the movement path or may correspond to a position along the movement path. The target position may be set as, for example, a point, a line, a frame, an area, or the like. The target position may be the same as the display position.

[0042] The output information control unit 146 controls the display control unit 14d and the audio control unit 14e, and ultimately the display device 8 and the audio output device 9, so that the display device 8 and the audio output device 9 output the desired information in the desired manner, for example, at each stage of parking assistance, such as starting and ending, determining the target position, calculating the route, and guidance control.

[0043] The route setting unit 147 sets a movement route from the current position of the vehicle 1 to the target position by a known method or the like, based on, for example, the current position of the vehicle 1, i.e., the vehicle itself, the determined target position, the detection result of an obstacle, and the like. In addition, the route setting unit 147 can update (correct) the movement route including the target position when the guidance control unit 148 guides the vehicle 1. That is, the guidance control unit 148 updates the movement route based on detected objects (obstacles and parking space lines) that are detected periodically. That is, the route setting unit 147 performs feedback control. The route setting unit 147 can determine the target position in the same manner as the target position determination unit 145.

[0044] The guidance control unit 148 controls each unit so that the vehicle 1 moves along the calculated movement route. That is, the guidance control unit 148 guides the vehicle 1. For example, in the case of the vehicle 1 that moves by creep or the like without operating the accelerator pedal, the guidance control unit 148 can move the vehicle 1 along the movement route by controlling the steering system 13 according to the position of the vehicle 1. In addition, the guidance control unit 148 can control not only the steering system 13 but also a driving mechanism such as an engine or a motor, and a brake system 18 as a braking mechanism. In addition, the guidance control unit 148 may control, for example, the output information control unit 146, the display control unit 14d, the audio control unit 14e, and further the display device 8 and the audio output device 9 to guide the driver to the movement of the vehicle 1 along the movement route by display output and audio output according to the position of the vehicle 1. The guidance control unit 148 sets a target speed, acceleration, and deceleration (negative acceleration), and controls the vehicle 1 so that the vehicle moves at the set target speed, acceleration, and deceleration. At this time, when the travel route is updated by the route setting unit 147, the guidance control unit 148 moves the vehicle 1 so that the vehicle moves along the updated travel route. In this case, various target values ​​(target speed, target acceleration, target deceleration) set by the guidance control unit 148 are also updated.

[0045] The storage unit 149 stores data used in the calculations in the ECU 14 or data calculated in the calculations in the ECU 14 .

[0046] FIG. 5 is a flowchart showing an example of a procedure of processing by the parking assistance device of the first embodiment. In the parking assistance system 100, processing is executed according to the procedure exemplified in FIG. 5. First, the parking space detection unit 143 detects a parking space and a parking boundary (S1), and the obstacle detection unit 142 detects an obstacle (S2). Next, the target position determination unit 145 determines a target position of the movement path of the vehicle 1 based on the detection results in S1 and S2 (S3). Next, the route setting unit 147 calculates a movement path from the current position of the vehicle 1 to the determined target position (S4). Next, the guidance control unit 148 controls each unit so that the movement of the vehicle 1 along the calculated movement path is realized (S5). Note that the target position, the movement path, and the like can be appropriately corrected or updated while the vehicle 1 is moving along the movement path.

[0047] FIG. 6 is an exemplary schematic plan view showing the initial position, route, and target position of the vehicle when the target position is set corresponding to the parking space by the parking assistance device of the first embodiment. FIG. 6 is an example of a case where the vehicle 1 located at the initial position Ps moves to the target position Pa along the routes R1, R2 that turn back at the turn back position Pt. The target position Pa and the routes R1, R2 are set based on the detection results of the parking boundaries D1, D2, the obstacle B11, and other obstacles not shown at the initial position Ps. Specifically, for example, the ECU 14 converts the positions of the detected parking boundaries D1, D2, the obstacle B11, and the like into positions on the coordinates in a planar view from above the vehicle 1 as illustrated in FIG. 6 by, for example, a coordinate conversion based on calibration or geometric calculation, and calculates the target position Pa and the routes R1, R2, and the like on the coordinates. In the example of FIG. 6, the target position Pa is set between the parking boundaries D1, D2 of the detected parking space. In route R1, the initial position Ps is the starting position of the vehicle 1, and the turning-back position Pt is the stopping position of the vehicle 1. In route R2, the turning-back position Pt is the starting position of the vehicle 1, and the target position Pa is the stopping position of the vehicle 1.

[0048] Furthermore, after the target position Pa is determined by the target position determination unit 145, while the vehicle 1 is moving along the routes R1 and R2, the route setting unit 147 can update the initial target position Pa based on the detection results of the obstacle detection unit 142, the parking space detection unit 143, and the like during the movement. The closer the distance from the vehicle 1 is, the higher the detection accuracy of the parking boundaries D1 and D2 and the obstacle B11 may be. Therefore, according to this embodiment, the target position may be corrected with higher accuracy.

[0049] Fig. 7 is a diagram showing the time course of the vehicle speed when a first deceleration is used in the braking control of the parking assistant of the first embodiment. Fig. 8 is a diagram showing the time course of the vehicle speed when a second deceleration is used in the braking control of the parking assistant of the first embodiment.

[0050] In addition, the guidance control unit 148 performs braking control of the vehicle 1 using a plurality of decelerations that are set to become smaller as the moving distance, which is the distance between the starting position (initial position Ps, turning position Pt) of the vehicle 1 on the route R1, R2 and the stopping position (turning position Pt, target position Pa) of the vehicle 1 on the route R1, R2, becomes shorter. At this time, the guidance control unit 148 controls the brake system 18. The plurality of decelerations are a first deceleration when the moving distance is equal to or greater than a threshold, and a second deceleration when the moving distance is less than the threshold. The second deceleration is smaller than the first deceleration. In other words, the plurality of decelerations are set to become smaller in stages as the moving distance becomes shorter. In Figs. 7 and 8, time t1 is the start time of the deceleration operation, and time t2 is the stop time of the vehicle 1. Time t1 is calculated from the decelerations to be used (first deceleration, second deceleration) and time t2 (stop position). 7 and 8, the time t1 when the second deceleration is used is earlier than the time t1 when the first deceleration is used. In other words, when the moving distance is less than the threshold, the timing of the start of the deceleration operation is earlier than when the moving distance is equal to or greater than the threshold.

[0051] FIG. 9 is a flow chart showing an example of a procedure of braking processing by the parking assistance device of the first embodiment. In the parking assistance system 100, braking processing is executed in the procedure exemplified in FIG. 9. First, the guidance control unit 148 judges whether the moving distance is equal to or greater than a threshold (S11). If the moving distance is equal to or greater than the threshold (S11: Yes), the guidance control unit 148 uses a first deceleration as the deceleration and decelerates the vehicle 1 at the first deceleration (S12). If the moving distance is not equal to or greater than the threshold, that is, if the moving distance is less than the threshold (S11: No), the guidance control unit 148 uses a second deceleration as the deceleration and decelerates the vehicle 1 at the second deceleration (S13).

[0052] As described above, in this embodiment, the ECU 14 (parking assistance device) includes the route setting unit 147 and the guidance control unit 148 (control unit). The route setting unit 147 sets routes R1, R2 (movement routes) for the vehicle 1. The guidance control unit 148 controls the vehicle 1 by changing the acceleration according to the distance between the starting position (initial position Ps, turning position Pt) of the vehicle 1 on the routes R1, R2 and the stopping position (turning position Pt, target position Pa) of the vehicle 1 on the routes R1, R2.

[0053] According to such a configuration, vehicle 1 is controlled by changing the acceleration according to the distance between the starting position of vehicle 1 on the travel route and the stopping position of vehicle 1 on the travel route, thereby improving the accuracy of vehicle control (e.g., control of the vehicle's stopping position and vehicle speed) compared to a configuration in which the acceleration is not changed according to the distance.

[0054] Here, it is useful if the vehicle can be stopped accurately at a stop position included in the travel route. In this embodiment, the guidance control unit 148 performs braking control of the vehicle 1 using a plurality of decelerations set to become smaller as the distance between the starting position (initial position Ps, turning position Pt) of the vehicle 1 on the routes R1 and R2 and the stopping position (turning position Pt, target position Pa) of the vehicle 1 on the routes R1 and R2 becomes shorter.

[0055] According to such a configuration, the braking control of the vehicle 1 is performed using a plurality of decelerations that are set to be smaller as the moving distance, which is the distance between the starting position of the vehicle 1 on the route R1, R2 and the stopping position of the vehicle 1 on the route R1, R2, becomes shorter, so that the timing of starting braking becomes earlier as the moving distance becomes shorter. Therefore, compared to the case where the first deceleration is used in all braking controls, the time from the start of braking to the stop of the vehicle 1 can be extended even if the moving distance is short, so that the braking control of the vehicle 1 during that time can be performed with high accuracy. Therefore, the stopping position accuracy can be improved. For example, the number of corrections in the above-mentioned feedback control can be increased, so that the stopping position accuracy can be improved.

[0056] The plurality of decelerations include a first deceleration when the distance is equal to or greater than the threshold, and a second deceleration when the traveled distance is less than the threshold, the second deceleration being smaller than the first deceleration.

[0057] According to this configuration, the multiple deceleration rates are a first deceleration rate and a second deceleration rate, so that the complexity of braking control can be suppressed compared to a configuration in which three or more multiple deceleration rates are set.

[0058] Furthermore, when the distance is less than the threshold, the guidance control unit 148 starts the deceleration operation at an earlier timing than when the distance is equal to or greater than the threshold.

[0059] With this configuration, braking control can be performed with even greater precision when the distance is less than the threshold value.

[0060] The multiple decelerations are not limited to the first deceleration and the second deceleration. Fig. 10 is a diagram for explaining the decelerations used in the parking assistance device of the first modified example of the first embodiment. As shown in Fig. 10, the multiple decelerations may be set to linearly increase as the moving distance increases.

[0061] <Second embodiment> Next, a second embodiment will be described. The same components as those in the first embodiment are given the same reference numerals, and duplicated descriptions will be omitted.

[0062] In parking assistance, when the travel distance, which is the distance between the starting position and the stopping position included in the travel route, is relatively long, the driving force of the vehicle 1 may be increased at a relatively large rate of change to start the vehicle 1 quickly, and when the travel distance is relatively short, the driving force of the vehicle 1 may be increased at a relatively small rate of change to start the vehicle slowly. However, when the travel distance is relatively long and the target speed of the vehicle 1 is relatively low, there is a risk that the actual speed of the vehicle 1 will exceed the target speed immediately after the vehicle 1 starts. Therefore, in this embodiment, the following configuration is adopted to improve the speed accuracy of the vehicle 1.

[0063] FIG. 11 is an exemplary block diagram of a part of the configuration of the ECU (parking assistance device) of the parking assistance system of the second embodiment. As shown in FIG. 11, in this embodiment, the ECU 14 includes an acquisition unit 141, an obstacle detection unit 142, a parking space detection unit 143, a display position determination unit 144, a target position determination unit 145, an output information control unit 146, a route setting unit 147, a guidance control unit 148, a storage unit 149, and a target speed setting unit 150. The CPU 14a executes processing according to a program to function as the acquisition unit 141, the obstacle detection unit 142, the parking space detection unit 143, the display position determination unit 144, the target position determination unit 145, the output information control unit 146, the route setting unit 147, the guidance control unit 148, and the like. The storage unit 149 stores data used in the arithmetic processing of each unit, data of the result of the arithmetic processing, and the like. At least a part of the functions of each unit may be realized by hardware.

[0064] The target speed setting unit 150 sets a target speed of the vehicle 1 on the travel route set by the route setting unit 147. The target speed is, for example, the maximum speed in each section between the starting position and the stopping position of the vehicle 1 on the travel route. The target speed differs between the case where the vehicle 1 moves forward and the case where the vehicle 1 moves backward. For example, the target speed is higher when the vehicle 1 moves forward than when the vehicle 1 moves backward. The target speed may also differ according to the travel distance, which is the distance between the starting position and the stopping position of the vehicle 1 on the travel route. The target speed may also differ according to the shape of the route in each section (straight line, curved line, etc.). The target speed is a vehicle speed within a range that does not give the driver a sense of anxiety or discomfort when the vehicle 1 is performing automatic travel (parking assistance) and allows the automatic travel to be performed rationally.

[0065] FIG. 12 is a flowchart showing an example of the procedure of the process by the parking assistance device of the second embodiment. In the parking assistance system 100, the process is executed according to the procedure exemplified in FIG. 12. First, the parking space detection unit 143 detects a parking space and a parking boundary (S1), and the obstacle detection unit 142 detects an obstacle (S2). Next, the target position determination unit 145 determines a target position of the movement path of the vehicle 1 based on the detection results in S1 and S2 (S3). Next, the route setting unit 147 calculates a movement path from the current position of the vehicle 1 to the determined target position (S4). Next, the target speed setting unit 150 sets a target speed and the like (S25). Next, the guidance control unit 148 controls each unit so that the movement of the vehicle 1 along the calculated movement path is realized (S5). At this time, the guidance control unit 148 controls the driving force and braking force of the vehicle 1 so that the parameters related to the movement of the vehicle 1 become the set target values ​​(for example, the target speed). The target position, the travel route, etc. may be appropriately corrected or updated while the vehicle 1 is moving along the travel route.

[0066] The guidance control unit 148 controls the driving force and braking force of the vehicle 1 so that the vehicle 1 moves so that its actual speed (actual speed) becomes the target speed set for each of the routes R1 and R2 (FIG. 6). The driving force is a forward force (propulsive force) applied to the wheels 3. That is, the driving force is a forward force (propulsive force) applied to the vehicle 1. The guidance control unit 148 can control the driving force by controlling the output of a driving mechanism such as an engine or a motor. Furthermore, the braking force is a force that stops the wheels 3 and a force that keeps the vehicle 1 stopped. That is, the braking force is a force that stops the vehicle 1 and a force that keeps the vehicle 1 stopped. The guidance control unit 148 can control the braking force by controlling a braking mechanism (brake system 18).

[0067] Moreover, the guidance control unit 148 variably controls the driving force and the braking force in the starting process of the vehicle 1. For example, when the moving distance between the starting position and the stopping position is less than the distance threshold, the guidance control unit 148 increases the driving force of the vehicle 1 at a first rate of change when the vehicle 1 starts. When the moving distance is equal to or greater than the distance threshold and the target speed is equal to or greater than the speed threshold, the guidance control unit 148 increases the driving force at a second rate of change greater than the first rate of change when the vehicle 1 starts. When the moving distance is equal to or greater than the distance threshold and the target speed is less than the speed threshold, the guidance control unit 148 increases the driving force at a first rate of change. The first rate of change, the second rate of change, the distance threshold, and the speed threshold are set in advance. The first rate of change and the second rate of change are the rate of change in the driving force per unit time. In other words, when the moving distance is less than the distance threshold, the guidance control unit 148 sets the acceleration of the vehicle 1 to the first acceleration when the vehicle 1 starts. Furthermore, when the travel distance is equal to or greater than the distance threshold and the target speed is equal to or greater than the speed threshold, the guidance control unit 148 sets the acceleration of the vehicle 1 to a second acceleration greater than the first acceleration. Furthermore, when the travel distance is equal to or greater than the distance threshold and the target speed is less than the speed threshold, the guidance control unit 148 sets the acceleration of the vehicle 1 to the first acceleration.

[0068] Furthermore, when the travel distance is less than the distance threshold, the guidance control unit 148 reduces the braking force of the vehicle 1 at the start of the vehicle 1 at the third rate of change. When the travel distance is equal to or greater than the distance threshold and the target speed is equal to or greater than the speed threshold, the guidance control unit 148 reduces the braking force at the start of the vehicle 1 at a fourth rate of change greater than the third rate of change. When the travel distance is equal to or greater than the distance threshold and the target speed is less than the speed threshold, the guidance control unit 148 reduces the braking force at the third rate of change. The third rate of change and the fourth rate of change are preset. The third rate of change and the fourth rate of change are the rate of change of the braking force per unit time.

[0069] Fig. 13 is a flowchart showing an example of a procedure of a starting process by the parking assistance device of the second embodiment. Fig. 14 is a diagram showing an example of a relationship between the driving force and the braking force and the elapsed time in the starting process by the parking assistance device of the second embodiment.

[0070] In the parking assistance system 100, the starting process is executed in the procedure exemplified in Fig. 13. First, the guidance control unit 148 judges whether the moving distance is less than the distance threshold (S31). If the moving distance is less than the distance threshold (S31: Yes), the guidance control unit 148 starts the vehicle 1 slowly regardless of the target speed (S32). Specifically, the guidance control unit 148 reduces the braking force of the vehicle 1 at a third rate of change, and then increases the driving force of the vehicle 1 at a first rate of change.

[0071] Furthermore, if the travel distance is not less than the distance threshold, i.e., if the travel distance is equal to or greater than the distance threshold (S31: No), the guidance control unit 148 determines whether the target speed is equal to or greater than the speed threshold (S33). If the target speed is not equal to or greater than the speed threshold (S33: No), the guidance control unit 148 proceeds to S32 and starts the vehicle 1 slowly. In other words, if the travel distance is equal to or greater than the distance threshold (S31: No) and the target speed is less than the speed threshold (S33: No), the guidance control unit 148 proceeds to S32 and reduces the braking force of the vehicle 1 at a third rate of change, and then increases the driving force of the vehicle 1 at a first rate of change.

[0072] Furthermore, when the travel distance is equal to or greater than the distance threshold (S31: No) and the target speed is equal to or greater than the speed threshold (S33: Yes), the guidance control unit 148 quickly starts the vehicle 1 (S34). Specifically, the guidance control unit 148 reduces the braking force at a fourth rate of change, and then increases the driving force at a second rate of change.

[0073] The relationship between the driving force and braking force and the elapsed time in the above starting process is, for example, as shown in Fig. 14. In Fig. 14, line L1 shows the case where the vehicle 1 is started quickly, and line L2 shows the case where the vehicle 1 is started slowly. In Fig. 14, the driving force shown in the upper half of the vertical axis increases toward the top, and the braking force shown in the lower half of the vertical axis increases toward the bottom. In other words, the braking force decreases toward the top. Line L1 has a greater gradient than line L2.

[0074] Time t11 is the time when the acceleration reaches the first acceleration threshold in the case of a quick start. Time t13 is the time when the vehicle 1 has traveled a first distance from time t11 when the actual acceleration of the vehicle 1 reaches the first acceleration threshold in the case of a quick start. The guidance control unit 148 determines that the vehicle 1 may have started at time t11, and keeps the driving force constant. The guidance control unit 148 determines that the vehicle 1 has definitely started at time t13, and increases the driving force.

[0075] Time t12 is the time when the acceleration reaches a second acceleration threshold value that is smaller than the first acceleration threshold value in the case of a slow start. Time t14 is the time when the vehicle 1 has traveled a first distance from time t12 when the acceleration reaches the second acceleration threshold value in the case of a slow start. The guidance control unit 148 determines that the vehicle 1 may have started at time t12, and holds the driving force. The guidance control unit 148 determines that the vehicle 1 has definitely started at time t14, and thereafter increases the driving force. The acceleration of the vehicle 1 in the case of a quick start is greater than the acceleration of the vehicle 1 in the case of a slow start. A slow start is also called a careful start.

[0076] The reason why vehicle 1 is started quickly as described above is to make the start timing of vehicle 1 earlier. Also, the reason why vehicle 1 is started slowly is to further suppress the feeling of jumping out (feeling of sudden acceleration) that accompanies sudden acceleration of vehicle 1. In other words, when priority is given to the start timing between the start timing of vehicle 1 and suppression of the feeling of vehicle 1 jumping out, vehicle 1 is started quickly. When priority is given to suppression of the feeling of vehicle 1 jumping out between the start timing of vehicle 1 and suppression of the feeling of vehicle 1 jumping out, vehicle 1 is started slowly.

[0077] As described above, in this embodiment, the ECU 14 (parking assistance device) includes a route setting unit 147, a target speed setting unit 150, and a guidance control unit 148 (control unit). The route setting unit 147 sets routes R1, R2 (movement routes) of the vehicle 1. The target speed setting unit sets a target speed between a starting position (initial position Ps, turning position Pt) of the vehicle 1 on the routes R1, R2 and a stopping position (turning position Pt, target position Pa) of the vehicle 1 on the routes R1, R2. The guidance control unit 148 controls the vehicle 1. When a moving distance between the starting position and the stopping position is less than a distance threshold, the guidance control unit 148 increases the driving force of the vehicle 1 at a first rate of change when the vehicle 1 starts. When the moving distance is equal to or greater than the distance threshold and the target speed is equal to or greater than a speed threshold, the guidance control unit 148 increases the driving force at a second rate of change greater than the first rate of change when the vehicle 1 starts. When the movement distance is equal to or greater than the distance threshold and the target speed is less than the speed threshold, the guidance control unit 148 increases the driving force at a first rate of change.

[0078] According to this configuration, when the moving distance between the starting position and the stopping position is equal to or greater than the distance threshold and the target speed is less than the speed threshold, the guidance control unit 148 increases the driving force at the first rate of change, which makes it easier to control the speed of the vehicle 1 compared to a configuration in which the driving force is increased at the second rate of change in this case. Therefore, the speed accuracy of the vehicle 1 can be improved.

[0079] Furthermore, when the travel distance is less than the distance threshold, the guidance control unit 148 reduces the braking force of the vehicle 1 at the start of the vehicle 1 at a third change rate. When the travel distance is equal to or greater than the distance threshold and the target speed is equal to or greater than the speed threshold, the guidance control unit 148 reduces the braking force at the start of the vehicle 1 at a fourth change rate greater than the third change rate. When the travel distance is equal to or greater than the distance threshold and the target speed is less than the speed threshold, the guidance control unit 148 reduces the braking force at the third change rate.

[0080] According to this configuration, when the travel distance is equal to or greater than the distance threshold and the target speed is less than the speed threshold, the guidance control unit 148 reduces the braking force at the third change rate, making it easier to control the speed of the vehicle 1 compared to a configuration in which the driving force is increased at the fourth change rate in this case. Therefore, the speed accuracy of the vehicle 1 can be improved.

[0081] The starting process is not limited to the example of FIG. 13. Here, FIG. 15 is a flowchart showing an example of the procedure of the starting process by the parking assistance device of the first modified example of the second embodiment. The example of FIG. 15 is different from the example of FIG. 13 in that S33 is not provided. In the example of FIG. 15, when the moving distance is not less than the distance threshold, that is, when the moving distance is equal to or greater than the distance threshold (S31: No), the guidance control unit 148 starts the vehicle 1 quickly (S34) regardless of the target speed. That is, in this modified example, the guidance control unit 148 changes the acceleration only depending on the moving distance, regardless of the target speed.

[0082] Although the embodiments of the present invention have been illustrated above, the above embodiments are merely examples and are not intended to limit the scope of the invention. The embodiments can be implemented in various other forms, and various omissions, substitutions, combinations, and modifications can be made without departing from the spirit of the invention. The configurations and shapes of each example can also be partially replaced. The specifications of each configuration, shape, etc. (structure, type, direction, shape, size, length, width, height, number, arrangement, position, etc.) can be appropriately changed and implemented. [Explanation of symbols]

[0083] 1...vehicle, 14...ECU (parking assistance device), 142...obstacle detection unit, 143...parking space detection unit (boundary detection unit), 145...target position determination unit, 147...route setting unit, 148...guidance control unit, 150...target speed setting unit, Pa...target position (stop position), Ps...initial position (start position), Pt...turn position (start position, stop position), R1, R2...route (travel route).

Claims

1. A route setting unit that sets a travel route of the vehicle; a control unit that controls the vehicle by changing an acceleration in accordance with a distance between a starting position of the vehicle on the movement path and a stopping position of the vehicle on the movement path; a target speed setting unit that sets a target speed between the starting position and the stopping position; Equipped with the control unit increases a driving force of the vehicle at a first rate of change when the distance between the start position and the stop position is less than a distance threshold, increases the driving force of the vehicle at a second rate of change greater than the first rate of change when the distance is equal to or greater than the distance threshold and the target speed is equal to or greater than a speed threshold, and increases the driving force at the first rate of change when the distance is equal to or greater than the distance threshold and the target speed is less than the speed threshold, The target speed is greater when the vehicle is moving forward than when the vehicle is moving backward. Parking assistance device.

2. The control unit performs braking control of the vehicle using a plurality of decelerations that are set to become smaller as the distance between the starting position and the stopping position becomes shorter.

2. The parking assistance device according to claim 1.

3. the plurality of decelerations are a first deceleration when the distance is equal to or greater than a threshold, and a second deceleration when the distance is less than the threshold, The second deceleration is smaller than the first deceleration.

3. The parking assistance device according to claim 2.

4. When the distance is less than a threshold value, the control unit starts a deceleration operation at an earlier timing than when the distance is equal to or greater than the threshold value.

3. The parking assistance device according to claim 2.

5. the control unit reduces the braking force of the vehicle at a third rate of change when the distance is less than the distance threshold, reduces the braking force of the vehicle at a fourth rate of change greater than the third rate of change when the distance is equal to or greater than the distance threshold and the target speed is equal to or greater than the speed threshold, and reduces the braking force at the third rate of change when the distance is equal to or greater than the distance threshold and the target speed is less than the speed threshold.

2. The parking assistance device according to claim 1.

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