Parking assistance device, parking assistance method, and recording medium

Abstract

The present application relates to a parking assistance device that achieves an improvement in parking assistance accuracy, an operation section of which calculates a target speed that accompanies the passage of time until a vehicle is moved to a parking target position, an event detection section that detects a prescribed phenomenon, i.e., an event, that indicates the timing of reoperation of the target speed. In addition, an acquisition section acquires a current actual speed of the vehicle. Furthermore, upon detection of the event, the operation section performs reoperation of the target speed so as to make the target speed coincide with the current actual speed of the vehicle. Thus, the vehicle can be guided to the parking target position on the basis of the actual speed, so the vehicle can be stopped at the parking position with good accuracy.

Description

TECHNICAL FIELD

[0001] Embodiments of the present application relate to a parking assist device, a parking assist method, and a recording medium. BACKGROUND

[0002] A parking assist device that moves a vehicle to a target position with high precision is disclosed in Patent Literature 1 (Japanese Patent Application Publication No. 2019-38296).

[0003] Patent Literature 1: Japanese Patent Application Publication No. 2019-38296

[0004] Although the parking assist device disclosed in such Patent Literature 1 can move the vehicle to the target position with high precision, further improvement in precision is required. SUMMARY

[0005] The parking assist device of the embodiment has an operation section that calculates a target speed that accompanies the passage of time until the vehicle is moved to a parking target position, an event detection section that detects a prescribed phenomenon, that is, an event, that indicates the timing of reoperation of the target speed, and an acquisition section that acquires a current actual speed of the vehicle. Moreover, upon detection of the event, the operation section performs reoperation of the target speed so as to make the target speed coincide with the current actual speed of the vehicle. In this way, upon reoperation of the target speed, the calculation is performed taking into account the current actual speed, so even if the target speed greatly deviates from the actual speed, the target speed can be calculated toward the parking position in accordance with the current actual speed, and thus the parking position can be controlled with high precision. In addition, since the reoperation is performed only when the event occurs, and not according to each prescribed period, the processing load of the operation section can be reduced, and the parking assist control can be performed even if a cheap operation section with a slow processing speed is used.

[0006] In addition, in the parking assist device of the embodiment, the event detection section detects any one or a plurality of the following phenomena as the event: a phenomenon in which the parking assist operation is started and the vehicle has moved by a prescribed distance, a phenomenon in which the distance between the vehicle and the parking target position, that is, the remaining distance, becomes less than the distance required for the vehicle to stop that is calculated by the operation section at the start, a phenomenon in which a brake operation is detected, and a phenomenon in which the target position is updated. Thereby, the operation section can perform the reoperation only when the event occurs, and the processing load can be reduced. In addition, a cheap operation section with a slow processing speed can be used as the operation section.

[0007] Further, in the parking assistance apparatus of the embodiment, the operation section performs the operation of the target speed using a plurality of decelerations, wherein a smaller deceleration is used when the distance between the vehicle and the parking target position, that is, the remaining distance is large, and a larger deceleration is used when the remaining distance is small. Thus, in the case where the remaining distance is large, the vehicle can be guided at a relatively fast speed, and the time until the parking is completed can be shortened. Further, in the case where the remaining distance is small, the vehicle can be guided at a relatively slow speed, and the improvement of safety can be achieved.

[0008] Further, the parking assistance method of the embodiment has an operation step in which the operation section calculates a target speed accompanying the passage of time until the vehicle is moved to a parking target position, an event detection step in which the event detection section detects a prescribed phenomenon, that is, an event, indicating the timing of the re-operation of the target speed, and an acquisition step in which the acquisition section acquires a current actual speed of the vehicle. Also, in the operation step, when the event is detected, the operation section performs the re-operation of the target speed so that the target speed coincides with the current actual speed of the vehicle. Thus, when the target speed is recalculated, the calculation is performed taking the current actual vehicle speed into consideration, so that even if the target vehicle speed greatly deviates from the actual vehicle speed, the target vehicle speed can be calculated toward the parking position in accordance with the current actual vehicle speed, and thus the parking position can be controlled with good precision. Further, since the recalculation is performed only when the event occurs, not according to each prescribed period, the processing load of the operation section can be reduced, and the parking assistance control can be performed even if a cheap operation section having a slow processing speed is used.

[0009] Further, the recording medium of the embodiment stores a parking assistance program that causes a computer to function as an operation section that calculates a target speed accompanying the passage of time until a vehicle is moved to a parking target position, an event detection section that detects a prescribed phenomenon, that is, an event, indicating the timing of the re-operation of the target speed, and an acquisition section that acquires a current actual speed of the vehicle. Also, when the event is detected, the operation section performs the re-operation of the target speed so that the target speed coincides with the current actual speed of the vehicle. Thus, when the target speed is recalculated, the calculation is performed taking the current actual vehicle speed into consideration, so that even if the target vehicle speed greatly deviates from the actual vehicle speed, the target vehicle speed can be calculated toward the parking position in accordance with the current actual vehicle speed, and thus the parking position can be controlled with good precision. Further, since the recalculation is performed only when the event occurs, not according to each prescribed period, the processing load of the operation section can be reduced, and the parking assistance control can be performed even if a cheap operation section having a slow processing speed is used. BRIEF DESCRIPTION OF DRAWINGS

[0010] Figure 1is a perspective view showing a state in which a part of a vehicle to which the parking assistance device of the embodiment is applied is seen through.

[0011] Figure 2 is a top view of a vehicle to which the parking assistance device of the embodiment is applied.

[0012] Figure 3 is a diagram showing an instrument panel of a vehicle to which the parking assistance device of the embodiment is applied.

[0013] Figure 4 is a block diagram of the parking assistance device of the embodiment.

[0014] Figure 5 is a functional block diagram of the parking assistance device of the embodiment.

[0015] Figure 6 is a flowchart showing a flow of a parking assistance operation of the parking assistance device of the embodiment.

[0016] Figure 7 is a diagram for explaining a bad situation in which a vehicle passes by a target position or becomes short of the target position due to a parking assistance operation being performed without using actual speed at the time of parking assistance.

[0017] Figure 8 is a diagram for explaining a case where a vehicle is guided to a target position by a parking assistance operation using actual speed based on the parking assistance device of the embodiment.

[0018] Figure 9 is a diagram for explaining a deceleration used at the time of a parking assistance operation by the parking assistance device of the embodiment.

[0019] BRIEF DESCRIPTION OF THE DRAWINGS DETAILED DESCRIPTION

[0020] Hereinafter, a parking assistance device to which the embodiment of the present application is applied will be described.

[0021] (Configuration of a vehicle)

[0022] First, Figure 1 is a perspective view showing a state in which a part of a vehicle to which the parking assistance device of the embodiment is applied is seen through. Figure 2 is a top view of a vehicle to which the parking assistance device of the embodiment is applied. Figure 3is a view showing a dashboard of a vehicle to which a parking assistance device according to an embodiment is applied.

[0023] The parking assistance device according to an embodiment can be applied to a vehicle 1, for example, as shown in Figure 1 The vehicle 1 can be, for example, a car (an internal combustion engine car) having an internal combustion engine as a drive source, an electric car or a fuel cell car having an electric motor as a drive source, or the like. In addition, the vehicle 1 can be a hybrid car having both an internal combustion engine and an electric motor as drive sources, or a car having another drive source. In addition, the vehicle 1 can have various kinds of transmission devices, and can have various kinds of devices such as systems or components required for driving the internal combustion engine or the electric motor. In addition, the vehicle 1 can be configured in various ways in terms of the number and arrangement of devices for driving the wheels 3.

[0024] The vehicle 1 is provided with a passenger compartment 2a in which a passenger rides, in the vehicle body 2. In the passenger compartment 2a, a steering operation portion 4, an acceleration operation portion 5, a brake operation portion 6, a transmission operation portion 7, and the like are provided at positions operable by a driver seated on a driver's seat 2b. The steering operation portion 4 is, for example, a steering wheel protruding from a dashboard 24. The acceleration operation portion 5 is an accelerator pedal located under the driver's feet. The brake operation portion 6 is a brake pedal located under the driver's feet. The transmission operation portion 7 is, for example, a shift lever protruding from a center console. The positions of the steering operation portion 4, the acceleration operation portion 5, the brake operation portion 6, the transmission operation portion 7, and the like are not limited to those described above.

[0025] In addition, a display device 8 as a display output portion and a sound output device 9 as a sound output portion are provided in the passenger compartment 2a. The display device 8 is, for example, an LCD (Liquid Crystal Display), an OELD (Organic Electroluminescent Display), or the like. The sound output device 9 is, for example, a speaker. In addition, the display device 8 is covered with a transparent operation input portion 10 such as a touch panel. A passenger can visually confirm an image displayed on a display screen of the display device 8 via the operation input portion 10. In addition, the passenger can perform an operation input via the operation input portion 10 by performing a contact operation on a position corresponding to the image displayed on the display screen of the display device 8 with a finger or the like.

[0026] These components, such as the display device 8, the sound output device 9, and the operation input unit 10, are, for example, located in the center of the instrument panel 24 in the vehicle width direction (left-right direction) of the monitor device 11. The monitor device 11 includes, for example, operation input units such as switches, dials, joysticks, and buttons. Alternatively, a sound output device different from the monitor device 11 can be installed in other locations within the passenger compartment 2a, and sound can be output from both the sound output device 9 of the monitor device 11 and other sound output devices. Furthermore, the monitor device 11 can, for example, function as a navigation system or an audio system.

[0027] In addition, such as Figure 3 As shown, a display device 12, different from the display device 8, is provided inside the passenger compartment 2a. This display device 12 is provided, for example, in the instrument panel section 25 of the instrument panel 24. Specifically, the display device 12 is located approximately in the center of the instrument panel section 25, between the speed display section 25a and the tachometer display section 25b.

[0028] The screen 12a of display device 12 is smaller than the screen 8a of display device 8. Display device 12 primarily displays images representing information related to parking assistance for vehicle 1. The amount of information displayed on display device 12 may be less than the amount of information displayed on display device 8. Display device 12 may be, for example, an LCD or an OLED. Furthermore, the information displayed on display device 12 may also be displayed on display device 8.

[0029] In addition, such as Figure 1 , 2 As shown, vehicle 1 is, for example, a four-wheeled car, with two front wheels 3F on the left and right and two rear wheels 3R ​​on the left and right. All four wheels 3 are configured to be steerable.

[0030] (Hardware composition of parking assistance devices)

[0031] Figure 4 This is a block diagram of the parking assistance device 100 according to an embodiment. As shown... Figure 4As shown, 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 causes the actuator 13a to act by electric control of an ECU 14 (Electronic Control Unit) or the like. The steering system 13 is, for example, an electric power steering system, an SBW (Steer By Wire) system, or the like. The steering system 13 assists the steering force by the actuator 13a adding an assist torque to the steering portion 4, and also steers the wheels 3 by the actuator 13a. In this case, the actuator 13a can steer one wheel 3 or a plurality of wheels 3. Further, the torque sensor 13b detects, for example, the torque given to the steering portion 4 by the driver.

[0032] Further, as shown in FIG. 1, the vehicle 1 has a plurality of cameras 15 that capture the surroundings of the vehicle 1. The cameras 15 are, for example, digital camera devices that have a CCD (Charge Coupled Device), a CIS (CMOS Image Sensor), or the like as a camera element. The cameras 15 output video data at a predetermined frame rate. The cameras 15 have a wide-angle lens or a fish-eye lens that can capture a range of, for example, 140° to 190° in the horizontal direction. Further, the optical axis of the cameras 15 is set to be directed obliquely downward. Thus, the cameras 15 sequentially capture the environment outside the periphery of the vehicle 1, including the road surface on which the vehicle 1 can travel and the area in which the vehicle 1 can park, and output the captured images as video data. Figure 2

[0033] The camera 15a is provided to a wall portion below the door 2h of the trunk, for example, at the end portion 2e on the rear side of the vehicle body 2. The camera 15b is provided to the right side mirror 2g, for example, at the end portion 2f on the right side of the vehicle body 2. The camera 15c is provided to the front bumper or the like, for example, at the end portion 2c on the front side of the vehicle 2. The camera 15d is provided to the left side mirror 2g as a protruding portion on the left side in the vehicle width direction of the vehicle body 2, for example, at the end portion 2d.

[0034] The ECU 14 performs arithmetic processing and image processing based on the image data obtained by the plurality of cameras 15, generates an image with a wider angle of view, or generates a virtual bird's-eye image (overhead image) that views the vehicle 1 from above. Further, the ECU 14 identifies a division line or the like shown on the road surface in the periphery of the vehicle 1 from the images of the cameras 15, and detects (extracts) a parking area shown by the division line or the like.

[0035] Further, as shown in FIG. 1, the vehicle 1 has a plurality of cameras 15 that capture the surroundings of the vehicle 1. The cameras 15 are, for example, digital camera devices that have a CCD (Charge Coupled Device), a CIS (CMOS Image Sensor), or the like as a camera element. The cameras 15 output video data at a predetermined frame rate. The cameras 15 have a wide-angle lens or a fish-eye lens that can capture a range of, for example, 140° to 190° in the horizontal direction. Further, the optical axis of the cameras 15 is set to be directed obliquely downward. Thus, the cameras 15 sequentially capture the environment outside the periphery of the vehicle 1, including the road surface on which the vehicle 1 can travel and the area in which the vehicle 1 can park, and output the captured images as video data. Figure 1 Figure 2 ​​As shown, four distance measuring sections 16a to 16d and eight distance measuring sections 17a to 17h are provided in the vehicle body 2 as the plurality of distance measuring sections 16, 17, for example. The distance measuring sections 16, 17 are sonar devices that emit ultrasonic waves and capture reflected waves thereof, for example. The sonar devices are also referred to as sonar sensors or ultrasonic detectors. The ECU 14 determines the presence or absence of an object such as an obstacle located around the vehicle 1 and a distance to the object based on detection results of the distance measuring sections 16, 17. Further, the distance measuring sections 17 are used for detection of objects at a relatively short distance, and the distance measuring sections 16 are used for detection of objects at a relatively long distance than the distance measuring sections 17. In addition, the distance measuring sections 17 are used for detection of objects in front of and behind the vehicle 1, for example, and the distance measuring sections 16 are used for detection of objects at side of the vehicle 1.

[0036] Further, as shown, Figure 4 In the parking assistance device 100, the ECU 14, the monitor device 11, the steering control system 13, the distance measuring sections 16, 17, and the like are electrically connected via an in-vehicle network 23 as an electric communication line, in addition to a brake system 18, a steering angle sensor 19, an acceleration sensor 20, a shift sensor 21, a wheel speed sensor 22, and the like. The in-vehicle network 23 is configured as a CAN (Controller Area Network), for example.

[0037] The ECU 14 controls the steering control system 13, the brake system 18, and the like by transmitting a control signal via the in-vehicle network 23. In addition, the ECU 14 acquires detection results of the torque sensor 13b, the brake sensor 18b, the steering angle sensor 19, the distance measuring sections 16, 17, the acceleration sensor 20, the shift sensor 21, the wheel speed sensor 22, and the like, an operation signal of the operation input section 10, and the like via the in-vehicle network 23.

[0038] The ECU 14 has a CPU 14a (Central Processing Unit), a ROM 14b (ReadOnly Memory), a RAM 14c (Random Access Memory), a display control section 14d, a sound control section 14e, an SSD 14f (Solid State Drive, flash memory), and the like, for example. The CPU 14a performs various arithmetic processes and controls such as image processing related to images displayed on the display devices 8, 12, determination of a target position of the vehicle 1, calculation of a movement path of the vehicle 1, determination of the presence or absence of interference with an object, automatic control of the vehicle 1, release of the automatic control, and the like, for example.

[0039] The CPU 14a reads out a program installed and stored in the nonvolatile storage device such as the ROM 14b, and performs an arithmetic process according to the program. Specifically, the parking assist program for performing the parking assist operation described later, and the deceleration data for adjusting the moving speed of the vehicle 1 at the time of parking assist are stored in the ROM 14b. The CPU 14a performs parking assist by acting on the basis of the parking assist program and the deceleration data.

[0040] The RAM 14c temporarily stores various data used in the arithmetic operation of the CPU 14a. The display control section 14d mainly performs image processing using the image data obtained by the imaging section 15 in the arithmetic process of the ECU 14, and the composition of the image data displayed on the display device 8, and the like. The sound control section 14e mainly performs processing of the sound data output by the sound output device 9 in the arithmetic process of the ECU 14. The SSD 14f is a rewritable nonvolatile storage section that continues to store data even in the case where the power supply to the ECU 14 is turned off.

[0041] Further, the CPU 14a, the ROM 14b, and the RAM 14c, and the like can be integrated in the same package. In addition, the ECU 14 can be replaced with a DSP (Digital Signal Processor) or another logic arithmetic processor or logic circuit, and the like. In addition, an HDD (Hard Disk Drive) can be provided instead of the SSD 14f, and the SSD 14f or the HDD can be provided separately from the ECU 14.

[0042] The brake system 18 is, for example, an ABS (Anti-Lock Brake System) that suppresses lock of a brake, an ESC (Electronic Stability Control) that suppresses side slip of the vehicle 1 at the time of turning, an electric brake system that enhances brake force (that performs brake assist), a BBW (Brake By Wire), and the like.

[0043] The brake system 18 brakes the vehicle 1 from the actuator 18a via the wheels 3. In addition, the brake system 18 detects a sign of lock of a brake, a sign of wheel spin of the wheels 3, a sign of side slip, and the like on the basis of a difference in rotation of the left and right wheels 3, and the like, and performs various controls. The brake sensor 18b is, for example, a sensor that detects the position of the movable section of the brake operation section 6. The brake sensor 18b detects the position of the brake pedal that is the movable section. The brake sensor 18b includes a displacement sensor.

[0044] The steering angle sensor 19 is, for example, a sensor that detects the amount of steering manipulation of the steering manipulation unit 4 such as a steering wheel. The steering angle sensor 19 is configured using, for example, a Hall element. The ECU 14 acquires, from the steering angle sensor 19, the amount of steering manipulation of the steering manipulation unit 4 by the driver, the amount of steering manipulation of each wheel 3 at the time of automatic steering manipulation, and the like, and performs various controls. Further, the steering angle sensor 19 detects the rotation angle of a rotating portion included in the steering manipulation unit 4.

[0045] The acceleration sensor 20 is, for example, a sensor that detects the position of the movable portion of the acceleration operation unit 5. The acceleration sensor 20 detects the position of the accelerator pedal which is the movable portion. The acceleration sensor 20 includes a displacement sensor.

[0046] The shift sensor 21 is, for example, a sensor that detects the position of the movable portion of the shift operation unit 7. The shift sensor 21 detects the position of the movable portion such as a lever, an arm, or a button. The shift sensor 21 can include a displacement sensor or can be configured as a switch.

[0047] The wheel speed sensor 22 is a sensor that detects the amount of rotation or the number of revolutions per unit time of the wheel 3. The wheel speed sensor 22 outputs the number of wheel speed pulses indicating the detected number of revolutions as a sensor value. The wheel speed sensor 22 is 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 performs various controls. Further, the wheel speed sensor 22 can be provided to the brake system 18. In this case, the ECU 14 acquires the detection result of the wheel speed sensor 22 via the brake system 18.

[0048] Further, the configuration, arrangement, and electrical connection method of the various sensors and actuators described above are one example, and can be arbitrarily set and changed.

[0049] (Functional Configuration of Parking Assistance Device)

[0050] Next, a functional block diagram of each function realized by the CPU 14a executing the parking assistance program stored in the ROM 14b will be shown in Figure 5 As shown in this Figure 5 , the CPU 14a functions as an acquisition unit 141, an obstacle detection unit 142, a parking area detection unit 143, a candidate position setting unit 144, a target position determination unit 145, an output information control unit 146, a path calculation unit 147, a guidance control unit 148, and a direction setting unit 150 by executing the parking assistance program. Further, in the ROM 14b, in addition to the parking assistance program, deceleration data and the like used for the calculation process of the parking assistance are stored.

[0051] The acquisition unit 141 acquires various data or signals and the like. The acquisition unit 141 acquires, for example, data or signals such as detection results of each sensor, operation inputs, instruction inputs, and image data. In addition, the acquisition unit 141 acquires, for example, a signal based on an operation input of the operation unit 14g which is a button or a switch and the like. In addition, the acquisition unit 141 acquires an actual speed of the vehicle 1 calculated based on a sensor value of the wheel speed sensor 22 and the like by the ECU 14 and the like.

[0052] The obstacle detection unit 142 detects an obstacle which obstructs the travel of the vehicle 1. The obstacle is, for example, another vehicle, a wall, a pillar, a fence, a protrusion, a step, a wheel stop, or an object and the like. The obstacle detection unit 142 detects the presence or absence, height, and size of the obstacle and the like by various methods. The obstacle detection unit 142 detects the obstacle based on, for example, detection results of the ranging units 16, 17. In addition, the ranging units 16, 17 detect an object corresponding to the height of the beam thereof. In addition, the obstacle detection unit 142 detects the presence or absence and height of the obstacle based on detection results of the wheel speed sensor 22 and the acceleration sensor and detection results of the ranging units 16, 17. In addition, the obstacle detection unit 142 can also detect the height of the obstacle based on an image captured by the imaging unit 15.

[0053] The parking area detection unit 143 detects a parking area provided as a sign or an object. The parking area refers to a region set to park the vehicle 1 to the place as a target or a reference. In addition, the parking boundary is a boundary or an outer edge of the parking area, and is, for example, a division line, a frame line, a straight line, a tape, a step, or an edge thereof and the like. The parking area detection unit 143 detects the parking area and the parking boundary, for example, by performing image processing on an image captured by the imaging unit 15.

[0054] The candidate position setting unit 144 sets at least one candidate position which is a candidate of a target position (= end point position) of a movement path of the vehicle 1. The candidate position setting unit 144 sets the candidate position based on at least one of detection results of the obstacle detection unit 142 and detection results of the parking area detection unit 143.

[0055] The direction setting unit 150 sets a direction of the vehicle 1 at each candidate position. The direction setting unit 150 sets the direction of the vehicle 1 at the candidate position based on at least one of detection results of the obstacle detection unit 142 and detection results of the parking area detection unit 143. In a case where a parking area is detected, the direction setting unit 150 sets the direction of the vehicle 1 based on the parking area.

[0056] The target location determination unit 145 determines the target location from at least one candidate location. From the at least one candidate location ranked based on predetermined conditions, the target location determination unit 145 determines the higher-ranking candidate location (the superior candidate location) as the target location. Additionally, the target location determination unit 145 determines the candidate location selected by the passenger's operation input as the target location from the at least one candidate location.

[0057] The output information control unit 146 controls the display device 8, 12 or the sound output device 9 via the display control unit 14d and the sound control unit 14e to output specified information in a specified manner at each stage of parking assistance, such as the start, end, target position determination, path calculation and guidance control.

[0058] The path calculation unit 147 is an example of an arithmetic unit and an event detection unit. Based on the current position of vehicle 1, the determined target position, and the detection results of obstacles, it calculates the movement path from the current position of vehicle 1 to the target position and the target speed. In addition, the path calculation unit 147 detects the specified events described later, and if such an event is detected, it calculates the target speed based on the actual speed of vehicle 1.

[0059] The guidance control unit 148 controls various components to move the vehicle 1 along a calculated movement path. When the vehicle 1 is moving with creep when the accelerator pedal is not in operation, the guidance control unit 148 controls the steering system 13 based on the position of the vehicle 1, causing the vehicle 1 to move along the movement path. In addition to controlling the steering system 13, the guidance control unit 148 can also control drive mechanisms such as the engine or motor, and the braking system 18, which serves as the braking mechanism. Furthermore, the guidance control unit 148 can control the display devices 8 and 12 or the sound output device 9 via the output information control unit 146, the display control unit 14d, and the sound control unit 14e, guiding the driver to move the vehicle 1 along the movement path through display output or sound output corresponding to the position of the vehicle 1.

[0060] (Parking assistance actions)

[0061] Next, use Figure 6 The flowchart illustrates the parking assistance operation in the parking assistance device 100 according to the embodiment. Figure 6 In the flowchart, the obstacle detection unit 142 first detects obstacles (step S1). Next, the parking area detection unit 143 detects the parking area and parking boundary (step S2). Next, the candidate position setting unit 144 sets at least one candidate position as the target position (end point) of the vehicle 1's movement path based on the detection results of steps S1 and S2 (step S3).

[0062] Next, the acquisition unit 141 acquires an operation input indicating the start of the parking assist (step S4). That is, in the case of the parking assist device of this embodiment, before the input operation instruction, each of the processes of step S1 to step S3 is executed.

[0063] Next, the target position determination unit 145 determines a target position from the at least one candidate position (step S5). Specifically, in step S5, the target position determination unit 145 ranks each of the detected candidate positions, and determines the candidate position of the highest order as the target position. Further, the target position determination unit 145 can also determine the candidate position selected by the operation input of the passenger as the target position.

[0064] Next, the path calculation unit 147 calculates a movement path from the current position of the vehicle 1 to the determined target position (step S6). Next, the guidance control unit 148 controls each unit so that the vehicle 1 moves along the calculated movement path (step S7). Next, the path calculation unit 147 detects whether or not the occurrence of an event described later in the movement of the vehicle 1 along the movement path (step S8).

[0065] In the case where the event has occurred (step S8: YES), the process returns to step S6, and the path calculation unit 147 re-calculates the target speed taking into account the actual speed of the vehicle 1. In contrast, in the case where the event has not occurred (step S8: NO), the guidance control unit 148 continues the movement control of the vehicle 1 along the calculated movement path. Next, in step S9, the guidance control unit 148 determines whether or not the vehicle 1 has reached the target position of the parking area. In the case where the vehicle 1 has not reached the target position of the parking area (step S9: NO), the process returns to step S7, and the guidance control unit 148 continues the movement control of the vehicle 1. If the vehicle 1 reaches the target position of the parking area (step S9: YES), the parking assist action shown in the flowchart ends. Figure 6

[0066] (Remaining calculation action at the time of event occurrence)

[0067] Here, the re-calculation action of the target speed at the time of event occurrence in step S8 will be described. First, in the case where the actual speed is less than the target speed, the target speed is re-calculated so as to be higher than the actual speed. In contrast, in the case where the actual speed is greater than the target speed, the target speed is re-calculated so as to be lower than the actual speed. Figure 7 A graph showing the control accuracy of the parking assist device that becomes a comparative example in this embodiment is shown in FIG. 10. The solid line graph is a graph of the actual speed of the vehicle, and the broken line graph is a graph of the target speed. In addition, the horizontal axis indicates time, and the vertical axis indicates speed. Figure 7 (a) of FIG. 10 is a graph in the case where control is performed in which the actual speed is less than the target speed, Figure 7 (b) of FIG. 10 is a graph in the case where control is performed in which the actual speed is greater than the target speed.

[0068] As shown in FIG. 10, in the case where the actual speed is less than the target speed, the target speed is re-calculated so as to be higher than the actual speed. In contrast, in the case where the actual speed is greater than the target speed, the target speed is re-calculated so as to be lower than the actual speed. Figure 7 ​If the control is performed so that the actual speed is less than the target speed, as shown in (a), the actual speed becomes 0 km (stop state) before the vehicle 1 reaches the target position (position at which the remaining distance is 0 m). That is, an undesirable situation (traveling deficiency) occurs in which the parking assist operation ends just before the target position. In contrast, if the control is performed so that the actual speed is greater than the target speed, as shown in (b), the actual speed becomes 0 km (stop state) at a position at which the vehicle 1 passes the target position (position at which the remaining distance is 0 m). That is, an undesirable situation (passing) occurs in which the parking assist operation ends at a position at which the target position is passed. Figure 7

[0069] Thus, it is understood that if the target speed is calculated without considering the actual speed, the control accuracy is problematic. In addition, although the calculation of the target speed can be performed periodically at each predetermined time, in this case, there is a concern that the load on the CPU increases due to the periodic repetition of the calculation.

[0070] In the case of the parking assist device 100 of the embodiment, the path calculation section 147 re-calculates the target speed based on the current speed of the vehicle 1, that is, the actual speed, by the acquisition section 141 at each predetermined event. Specifically, the path calculation section 147 calculates the distance required until the vehicle 1 stops based on the pre-designated deceleration described later, the current actual speed, and the actual acceleration before the parking assist operation. The guidance control section 148 performs the movement control of the vehicle 1 based on the required distance. Figure 9

[0071] Here, immediately after the start of the parking assist operation and the start of the vehicle 1, the traveling speed becomes unstable in many cases. Therefore, the path calculation section 147 recognizes that an event occurs if, for example, the vehicle 1 advances a predetermined distance from the start is notified from the distance measuring sections 16, 17, and the like, and re-calculates the target speed, the target position, and the target acceleration based on the actual speed, the actual position, the actual acceleration, and the remaining distance of the vehicle.

[0072] In addition, in a case where the movement control of the vehicle 1 is performed by the guidance control section 148 so that the remaining distance becomes less than the distance required until the vehicle 1 stops calculated initially, the path calculation section 147 recognizes that an event occurs and re-calculates the target speed, the target position, and the target acceleration based on the actual speed, the actual position, the actual acceleration, and the remaining distance of the vehicle.

[0073] ​​In addition, the user's implementation of braking indicates that some element of disturbance such as an obstacle has occurred. Therefore, if the user's implementation of braking is detected by the braking system 18, the path calculation portion 147 recognizes that an event has occurred and re-computes the target speed, target position, and target acceleration based on the actual speed, actual position, actual acceleration, and remaining distance of the vehicle.

[0074] Also, in the case where the target position of the vehicle 1 is updated, the path calculation portion 147 recognizes that an event has occurred and re-computes the target speed, target position, and target acceleration based on the actual speed, actual position, actual acceleration, and remaining distance of the vehicle. That is, if an event has occurred, the path calculation portion 147 performs a computation to bring the actual speed into agreement with the target speed.

[0075] The timing of such recognition of an event is summarized as follows.

[0076] 1. An event is recognized to have occurred when the parking assist operation is started and the vehicle has moved a prescribed distance

[0077] 2. An event is recognized to have occurred when the remaining distance becomes less than the distance initially computed to be required to park the vehicle 1

[0078] 3. An event is recognized to have occurred when the user implements braking

[0079] 4. An event is recognized to have occurred when the target position of the vehicle 1 is updated

[0080] Further, the above four events are merely one example, and any phenomenon that necessitates re-computation of the target speed or target position, etc. can be recognized as an "event".

[0081] Figure 8 is a graph showing the transition of the target speed and actual speed when the target speed and target position are re-computed in accordance with each of the above events and the parking assist is performed. The graph of the broken line is a graph of the target speed, and the graph of the solid line is a graph of the actual speed. In addition, Figure 8 (a) of is a graph in the case where the actual speed is less than the target speed, Figure 8 (b) of is a graph in the case where the actual speed is greater than the target speed. Also, Figure 8 The "A" timing and "B" timing in (a) of Figure 8 (b) of indicate the timing at which an event has occurred, respectively.

[0082] As Figure 8In the case where the actual speed is smaller than the target speed, if an event occurs at the "A" timing, the path calculation section 147 re-computes the target speed, the target position, and the target acceleration based on the actual speed, the actual position, the actual acceleration, and the remaining distance of the vehicle, and the like, as shown in (a) of FIG. 9. Thus, as shown in (a) of FIG. 9, the target speed can be made to coincide with the actual speed, and the movement control of the vehicle 1 is performed in this state. Figure 8

[0083] Likewise, in the case where the actual speed is smaller than the target speed, if an event occurs at the "B" timing, the path calculation section 147 re-computes the target speed, the target position, and the target acceleration based on the actual speed, the actual position, the actual acceleration, and the remaining distance of the vehicle, and the like, as shown in (a) of FIG. 10. Thus, as shown in (a) of FIG. 10, the target speed can be made to coincide with the actual speed, and the movement control of the vehicle 1 is performed in this state. Figure 8 Figure 8

[0084] Further, as shown in (b) of FIG. 9, in the case where the actual speed is greater than the target speed, if an event occurs at the "A" timing, the path calculation section 147 re-computes the target speed, the target position, and the target acceleration based on the actual speed, the actual position, the actual acceleration, and the remaining distance of the vehicle, and the like. Thus, as shown in (b) of FIG. 9, the target speed can be made to coincide with the actual speed, and the movement control of the vehicle 1 is performed in this state. Figure 8 Figure 8

[0085] Likewise, in the case where the actual speed is greater than the target speed, if an event occurs at the "B" timing, the path calculation section 147 re-computes the target speed, the target position, and the target acceleration based on the actual speed, the actual position, the actual acceleration, and the remaining distance of the vehicle, and the like, as shown in (b) of FIG. 10. Thus, as shown in (b) of FIG. 10, the target speed can be made to coincide with the actual speed, and the movement control of the vehicle 1 is performed in this state. Figure 8 Figure 8

[0086] By performing the computation of making the target speed coincide with the actual speed in this way for each event, and performing the movement control of the vehicle 1 based on the computation result, as shown in (a) of FIG. 9 and (b) of FIG. 9, the actual speed of the vehicle can be made to be 0 km when the remaining distance becomes 0 m. That is, the vehicle 1 can be stopped to the target position with good accuracy. Figure 9 Figure 9

[0087] (Deceleration)

[0088] Here, the path calculation section 147 uses the deceleration corresponding to the remaining distance in the case of re-computing the target speed, the target position, and the like. Figure 4 is a graph showing one example of this deceleration. This​​​​​​​​​​ The example demonstrates that when the remaining distance is greater than a specified value, a first deceleration with a smaller deceleration is used in the calculation, and when the remaining distance is less than a specified value, a second deceleration with a larger deceleration is used in the calculation. The data for such first and second decelerations are stored in... ​ The ROM14b shown. The path calculation unit 147 reads the deceleration data corresponding to the remaining distance from the ROM14b and uses it for further calculation of the target speed, etc.

[0089] Therefore, when there is a long remaining distance, the vehicle can be controlled to move without slowing down, thus reducing the time required to stop. Conversely, when there is a short remaining distance, the vehicle can be controlled to move with greater deceleration, thereby ensuring safety.

[0090] Furthermore, in this example, two decelerations are used, namely the first and second decelerations, but more than three decelerations can also be used. In this case, more precise deceleration control can be achieved.

[0091] (Effects of the implementation method)

[0092] As explained above, the parking assistance device of this embodiment considers the current actual vehicle speed when recalculating the target vehicle speed. Therefore, even if the target vehicle speed deviates significantly from the actual vehicle speed, it can still calculate the target vehicle speed towards the parking position based on the current actual vehicle speed, thus enabling precise control of the parking position.

[0093] Furthermore, since the recalculation is not performed according to each prescribed cycle, but only when an event occurs, the processing load on the CPU14a can be reduced, and parking assistance control can be performed even when using a cheaper CPU with a slower processing speed.

[0094] (Modified Example)

[0095] The above-described embodiments are merely examples and do not limit the scope of the invention. The above-described embodiments can be implemented in various other ways, and various omissions, substitutions, combinations, and modifications can be made without departing from the spirit of the invention. Furthermore, the configuration and shape of each example can be partially changed. Additionally, the specifications (structure, type, direction, shape, size, length, width, height, number, arrangement, position, etc.) of each component and shape can be appropriately changed. Furthermore, the present invention can be applied to parking assistance in various types of parking lots and parking spaces. Furthermore, various settings or modifications can be made regarding the methods for detecting and setting the vehicle's position and direction, as well as the references for detecting and setting alternative positions and their directions. Additionally, the input signal can also be based on sound input to a microphone.

[0096] In addition, the configuration of the above-described embodiments, the effects, results, and advantages brought about by the configuration are one example. The present application can also be implemented by a configuration other than the configuration described in the above-described embodiments, and at least one of various effects based on the basic configuration or a derivative effect can be obtained.

Claims

1. A parking assist device characterized by comprising: having: an operation section that calculates a target speed that accompanies the passage of time until a vehicle is moved to a parking target position; an event detection section that detects a prescribed phenomenon, i.e., an event, that indicates a timing of re-calculation of the target speed; and an acquisition section that acquires a current actual speed of the vehicle, wherein, when the event is detected, the operation section re-calculates the target speed so as to coincide with the current actual speed of the vehicle, the event detection section detects, as the event, a phenomenon in which a distance between the vehicle and the parking target position, i.e., a remaining distance, becomes less than a distance required for the vehicle to stop that is calculated initially by the operation section.

2. The parking assistance apparatus according to claim 1, characterized in that the operation section uses a plurality of deceleration rates to perform the calculation of the target speed, wherein a smaller deceleration rate is used when the distance between the vehicle and the parking target position, i.e., the remaining distance, is greater, and a greater deceleration rate is used when the remaining distance is less.

3. A parking assistance method characterized by, having: an operation step in which an operation section calculates a target speed that accompanies the passage of time until a vehicle is moved to a parking target position; an event detection step in which an event detection section detects a prescribed phenomenon, i.e., an event, that indicates a timing of re-calculation of the target speed; and an acquisition step in which an acquisition section acquires a current actual speed of the vehicle, wherein, in the operation step, when the event is detected, the operation section re-calculates the target speed so as to coincide with the current actual speed of the vehicle, in the event detection step, the event detection section detects, as the event, a phenomenon in which a distance between the vehicle and the parking target position, i.e., a remaining distance, becomes less than a distance required for the vehicle to stop that is calculated initially by the operation section.

4. A recording medium that stores a parking assistance program, characterized in that the parking assistance program causes a computer to function as: an operation section that calculates a target speed that accompanies the passage of time until a vehicle is moved to a parking target position; an event detection section that detects a prescribed phenomenon, i.e., an event, that indicates a timing of re-calculation of the target speed; and an acquisition section that acquires a current actual speed of the vehicle, wherein, when the event is detected, the operation section re-calculates the target speed so as to coincide with the current actual speed of the vehicle, the event detection section detects, as the event, a phenomenon in which a distance between the vehicle and the parking target position, i.e., a remaining distance, becomes less than a distance required for the vehicle to stop that is calculated initially by the operation section.

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