Parking assistance device, parking assistance method, and non-transitory storage medium

Abstract

The present invention relates to a parking assistance device including an electronic control unit (14). The electronic control unit (14) sets a target speed profile that is the target of the vehicle speed of the vehicle (1) in such a manner that after accelerating the vehicle (1) from a guide start position at a prescribed acceleration, the vehicle (1) decelerates at a first deceleration during a period in which the remaining distance to the target position at which the vehicle (1) is to stop, i.e., the target stop position, is from a position of a first remaining distance to a position of a second remaining distance smaller than the first remaining distance, and the vehicle (1) decelerates at a second deceleration greater than the first deceleration during a period from the position of the second remaining distance to the target stop position. The electronic control unit (14) performs braking drive control of the vehicle (1) based on the target speed profile.

Description

Technical Field

[0001] Embodiments of the present invention relate to a parking assistance device, a parking assistance method, and a non - transitory storage medium. Background Art

[0002] 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 the parking area and steers the vehicle along the movement path, thereby guiding the vehicle to the parking area. In addition, there is known a parking assistance device that performs braking control and acceleration / deceleration control in addition to steering control when guiding the vehicle to the parking area.

[0003] In parking assistance, there are cases where it is desired to improve the parking position accuracy within the parking area. However, in the braking drive control for automatic parking such as braking control and acceleration / deceleration control, it is difficult to stop the vehicle with high accuracy within the parking area when the follow - up of the actual speed of the vehicle with respect to the target speed is low. Summary of the Invention

[0004] Embodiments provide a parking assistance device, a parking assistance method, and a non - transitory storage medium that can improve the parking position accuracy in the braking drive control for automatic parking.

[0005] The parking assistance device according to the embodiment includes an electronic control unit. The electronic control unit sets a target speed profile as the target of the vehicle speed in such a manner that after accelerating the vehicle from a start position of guidance at a prescribed acceleration, the vehicle decelerates at a first deceleration during a period when the remaining distance from the target position where the vehicle is to be parked, i.e., the target parking position, is from a position of a first remaining distance to a position of a second remaining distance smaller than the first remaining distance, and the vehicle decelerates at a second deceleration greater than the first deceleration during a period from the position of the second remaining distance to the target parking position. The electronic control unit performs braking drive control of the vehicle based on the target speed profile. According to this configuration, for example, the follow - up of the actual speed of the vehicle with respect to the target speed in the braking drive control for automatic parking can be improved. The improvement of the follow - up of the actual speed of the vehicle with respect to the target speed contributes to the improvement of the parking position accuracy in the braking drive control for automatic parking.

[0006] In the parking assistance device according to the embodiment, when the sum of the travel distance when the vehicle is accelerating at the specified acceleration, the travel distance when the vehicle is decelerating at the first deceleration, and the travel distance when the vehicle is decelerating at the second deceleration is greater than the distance from the guiding start position to the target parking position, the target speed profile may be set such that deceleration starts at a position with a remaining distance smaller than the first remaining distance and larger than the second remaining distance at the first deceleration. According to this structure, for example, even when the total travel distance during parking assistance is short, the parking position accuracy can be improved by decelerating in two stages.

[0007] In the parking assistance device according to the embodiment, when the sum of the travel distance when the vehicle is accelerating at the specified acceleration and the travel distance when the vehicle is decelerating at the second deceleration is greater than the distance from the guiding start position to the target parking position, the target speed profile may be set such that after the vehicle is accelerated at the specified acceleration, the vehicle is decelerated at the second deceleration without using the first deceleration. According to this structure, for example, when the influence of the decrease in the followability of the actual speed of the vehicle with respect to the target speed is small, one-stage deceleration with one deceleration can be performed.

[0008] The parking assistance device according to the embodiment may further include a storage unit that stores a table representing the first deceleration and the second deceleration for each upper limit speed during parking assistance. Additionally, in the parking assistance device according to the embodiment, the electronic control unit may include a storage unit that stores a table representing the first deceleration and the second deceleration for each upper limit speed during parking assistance. According to this structure, for example, since the first deceleration and the second deceleration are determined based on the upper limit speed, the parking position accuracy can be improved and it is not likely to cause discomfort to users such as drivers.

[0009] In the parking assistance device according to the embodiment, the electronic control unit may select the first deceleration and the second deceleration according to the driving mode. According to this structure, for example, since the first deceleration and the second deceleration corresponding to the driving mode selected by the user are determined, the parking position accuracy can be improved and it is not likely to cause discomfort to users such as drivers.

[0010] The parking assistance method according to the embodiment includes the following steps: setting a target speed profile as the target of the vehicle speed in such a manner that after accelerating the vehicle from the start position of guidance at a prescribed acceleration, the vehicle decelerates at a first deceleration during a period when the remaining distance from the target position where the vehicle stops, i.e., the target stop position, is from a position of a first remaining distance to a position of a second remaining distance smaller than the first remaining distance, and the vehicle decelerates at a second deceleration greater than the first deceleration during a period from the position of the second remaining distance to the target stop position; and performing braking drive control of the vehicle based on the target speed profile. According to this configuration, for example, it is possible to improve the followability of the actual speed of the vehicle with respect to the target speed in the braking drive control of automatic parking. The improvement of the followability of the actual speed of the vehicle with respect to the target speed contributes to the improvement of the parking position accuracy in the braking drive control of automatic parking.

[0011] A non - transitory storage medium stores commands that can be executed by one or more processors according to the embodiment and cause the one or more processors to perform the following functions: setting a target, i.e., a target speed profile, of the vehicle speed in such a manner that after accelerating the vehicle from the start position of guidance at a prescribed acceleration, the vehicle decelerates at a first deceleration during a period when the remaining distance from the target position where the vehicle stops, i.e., the target stop position, is from a position of a first remaining distance to a position of a second remaining distance smaller than the first remaining distance, and the vehicle decelerates at a second deceleration greater than the first deceleration during a period from the position of the second remaining distance to the target stop position; and performing braking drive control of the vehicle based on the target speed profile. According to this configuration, for example, it is possible to improve the followability of the actual speed of the vehicle with respect to the target speed in the braking drive control of automatic parking. The improvement of the followability of the actual speed of the vehicle with respect to the target speed contributes to the improvement of the parking position accuracy in the braking drive control of automatic parking. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Hereinafter, features, advantages, techniques, and industrial significance of exemplary embodiments of the present invention will be described with reference to the drawings, in which the same reference numerals denote the same elements, and:

[0013] Figure 1 is an exemplary and schematic perspective view showing a state in which a part of the passenger compartment of a vehicle equipped with the parking assistance device according to the embodiment is seen through.

[0014] Figure 2 is an exemplary top view of a vehicle equipped with the parking assistance device according to the embodiment.

[0015] Figure 3This is an exemplary and schematic diagram when looking at the instrument panel of a vehicle equipped with the parking assistance device according to the mounting embodiment from the rear of the vehicle.

[0016] Figure 4 This is an exemplary block diagram showing the structure of the control system including the parking assistance device according to the embodiment.

[0017] Figure 5 This is an exemplary and schematic block diagram showing the functional structure of the parking assistance device implemented in the control system according to the embodiment.

[0018] Figure 6 This is an exemplary and schematic diagram showing the guidance path generated in the parking assistance device according to the embodiment.

[0019] Figure 7 This is an exemplary and schematic diagram showing the target speed graph set in the parking assistance device according to the embodiment.

[0020] Figure 8 This is a flowchart showing an example of the parking assistance process during reverse guidance executed in the parking assistance device according to the embodiment.

[0021] Figure 9 This is an exemplary and schematic diagram showing the target speed graph set in the parking assistance device according to the embodiment when the target speed at the deceleration start time does not satisfy the upper limit speed in the parking assistance.

[0022] Figure 10 This is an exemplary and schematic diagram showing the target speed graph set in the parking assistance device according to the embodiment when the target speed at the deceleration start time does not satisfy the target speed during the second - stage transition. Detailed Embodiment

[0023] Hereinafter, exemplary embodiments of the present invention will be disclosed. The structure of the following embodiments is an example. In addition, the actions, results, and effects brought by this structure are examples. The present invention can also be implemented by structures other than those disclosed in the following embodiments, and can obtain at least one of various effects and derivative effects based on the basic structure.

[0024] Figure 1 This is an exemplary and schematic perspective view of a part of the passenger compartment 2a of the vehicle 1 equipped with the image processing device according to the embodiment in a perspective state. Figure 2 This is an exemplary and schematic top view of the vehicle 1 equipped with the parking assistance device according to the embodiment. Figure 3This is an exemplary and schematic diagram when looking at the dashboard of a vehicle equipped with the parking assistance device according to the mounting embodiment from the rear of the vehicle.

[0025] The vehicle 1 equipped with the parking assistance device according to the mounting embodiment can be an automobile (internal combustion engine vehicle) with an internal combustion engine (engine) as the drive source, an automobile (electric vehicle, fuel cell vehicle, etc.) with an electric motor (motor) as the drive source, or an automobile (hybrid vehicle) with both of them as the drive sources. In addition, the vehicle 1 can be equipped with various transmission devices, various devices (systems, components, etc.) required for driving the internal combustion engine and the electric motor. In addition, various settings can be made for the mode, number, layout, etc. of the devices related to the drive of the wheels 3 in the vehicle 1.

[0026] As Figure 1 illustrated, the vehicle body 2 of the vehicle 1 forms a passenger compartment 2a for an unillustrated occupant to ride in. Inside the passenger compartment 2a, a steering control unit 4, an acceleration operation unit 5, a braking operation unit 6, a shift operation unit 7, etc. are provided in a state facing the seat 2b of the driver as the occupant. The steering control unit 4 is, for example, a steering wheel protruding from the dashboard 24. The acceleration operation unit 5 is, for example, an acceleration pedal located at the driver's feet. The braking operation unit 6 is, for example, a brake pedal located at the driver's feet. The shift operation unit 7 is, for example, a shift lever protruding from the console.

[0027] In addition, inside the passenger compartment 2a, a display device 8 (display unit) and a sound output device 9 as a sound output unit are provided. The display device 8 is, for example, an LCD (Liquid Crystal Display), an OELD (Organic Electroluminescent Display), etc. The sound output device 9 is, for example, a speaker. In addition, the display device 8 is, for example, covered by a transparent operation input unit 10 such as a touch panel. The occupant (user) can visually confirm the image on the display screen displayed on the display device 8 via the operation input unit 10. In addition, the occupant (driver, etc.) 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 on the display screen displayed on the display device 8. The above display device 8, sound output device 9, operation input unit 10, etc. are, for example, provided in a monitoring device 11 located at the center in the vehicle width direction, that is, the left - right direction, of the dashboard 24. The monitoring device 11 can have operation input units such as switches, dials, joysticks, buttons, etc. that are not illustrated. In addition, an unillustrated sound output device can be provided at other positions in the passenger compartment 2a different from the monitoring device 11, and sound can be output from the sound output device 9 of the monitoring device 11 and the other sound output devices. In addition, the monitoring device 11 can, for example, be shared with a navigation system and an audio system.

[0028] In addition, inside the passenger compartment 2a, a display device 12 separate from the display device 8 is provided. As Figure 3 illustrated, the display device 12 is provided, for example, in the instrument panel portion 25 of the instrument panel 24, and is located between the speed display portion 25a and the engine speed display portion 25b at substantially the center of the instrument panel portion 25. As Figure 3 illustrated, the size of the screen 12a of the display device 12 is smaller than the size of the screen 8a of the display device 8. In the display device 12, an image representing information related to the parking assistance of the vehicle 1 can mainly be displayed. Information related to the parking assistance of the vehicle 1 includes text information, display information using an indicator, etc. The amount of information displayed by the display device 12 may also be less than the amount of information displayed by the display device 8. The display device 12 is, for example, an LCD, an OELD, etc. In addition, the information displayed by the display device 12 may also be displayed on the display device 8.

[0029] As Figure 1 and Figure 2 shown, the vehicle 1 is a four-wheel vehicle or the like, and has two left and right front wheels 3F and two left and right rear wheels 3R. All or part of the four wheels 3 can be steered.

[0030] In the vehicle body 2, as a plurality of imaging units 15, for example, four imaging units 15a to 15d are provided. The imaging unit 15 is, for example, a digital camera incorporating an imaging element such as a CCD (Charge Coupled Device) or a CIS (CMOS Image Sensor). The imaging unit 15 can output moving image data at a prescribed frame rate. The imaging unit 15 has a wide-angle lens or a fish-eye lens respectively, and can image a range of, for example, 140° to 220° in the horizontal direction. In addition, the optical axis of the imaging unit 15 is set to face obliquely downward. Thereby, the imaging unit 15 continuously images the external environment around the vehicle body 2 including the road surface on which the vehicle 1 can move and the area where the vehicle 1 can park, and outputs it as imaging image data.

[0031] The imaging unit 15a is located, for example, at the rear end 2e of the vehicle body 2, on the wall portion below the trunk lid 2h, to image the condition of the rear area of the vehicle 1. The imaging unit 15b is located, for example, at the right end 2f of the vehicle body 2, on the right side mirror 2g, to image the condition of the area including the front right, right side, and rear right of the vehicle 1. The imaging unit 15c is located, for example, at the front side of the vehicle body 2, that is, the front end 2c in the vehicle front-rear direction, on the front bumper or the like, to image the condition of the front area of the vehicle 1. The imaging unit 15d is located, for example, at the left side of the vehicle body 2, that is, the left end 2d in the vehicle width direction, on the side mirror 2g as the left protruding portion, to image the condition of the area including the front left, left side, and rear left of the vehicle 1. The electronic control unit 14 (refer to Figure 4 ) that constitutes the image processing device can perform arithmetic processing and image processing based on the captured image data obtained by the plurality of imaging units 15, and generate an image with a wider viewing angle, or generate a virtual bird's-eye view image of the vehicle 1 observed from above (directly above, obliquely above).

[0032] In addition, the vehicle 1 has a plurality of ranging units 16, 17 that can measure the distance to an object existing outside the vehicle 1. The ranging unit 16 is, for example, a millimeter-wave radar or the like, and can measure the distance to an object existing in the traveling direction of the vehicle 1. The traveling direction of the vehicle 1 represents, for example, the direction in which the vehicle 1 is facing. In the present embodiment, the vehicle 1 has a plurality of ranging units 16a to 16d. The ranging unit 16a is provided, for example, at the left end of the rear bumper of the vehicle 1, and can measure the distance to an object existing in the left rear of the vehicle 1. In addition, the ranging unit 16b is provided at the right end of the rear bumper of the vehicle 1, and can measure the distance to an object existing in the right rear of the vehicle 1. The ranging unit 16c is provided at the right end of the front bumper of the vehicle 1, and can measure the distance to an object existing in the right front of the vehicle 1. In addition, the ranging unit 16d is provided at the left end of the front bumper of the vehicle 1, and can measure the distance to an object existing in the left front of the vehicle 1. The ranging unit 16 can be used for detecting objects with a relatively long distance.

[0033] In addition, the vehicle 1 has a ranging unit 17 that can measure the distance to an object existing outside the vehicle 1 at a relatively short distance. The ranging unit 17 is, for example, a sonar that emits ultrasonic waves and captures the reflected waves. In the present embodiment, the vehicle 1 has a plurality of ranging units 17a to 17h. The ranging units 17a to 17d are provided on the rear bumper of the vehicle 1, and can measure the distance to an object existing behind the vehicle. The ranging units 17e to 17h are provided on the front bumper of the vehicle 1, and can measure the distance to an object existing in front of the vehicle 1.

[0034] In the present embodiment, for example, when the vehicle 1 stops, the distance measurement unit 16 can detect obstacles arranged adjacent to the vehicle 1 and obstacles located inside the space for parking, and measure the distance to the obstacle. Here, the obstacles arranged adjacent to the vehicle 1 represent, for example, adjacent vehicles, walls, etc. In addition, the obstacles located inside the space for parking refer to, for example, curbs, steps, walls, guardrails, etc. Further, for example, when an obstacle (object) approaches the vehicle 1 beyond a specified distance, the distance measurement unit 17 can detect the approaching obstacle (object) and measure the distance to the obstacle. As the specified distance, for example, it is 0.3 m. In particular, the distance measurement units 17a and 17d arranged on both sides of the rear of the vehicle 1 function as sensors (gap sonars) for measuring the distance between the rear corner of the vehicle 1 and an obstacle such as an adjacent vehicle when the vehicle 1 reverses into the parking area and further measuring the distance between the rear corner and an obstacle such as a wall after entering. The electronic control unit 14 can determine the presence or absence of an object such as an obstacle around the vehicle 1 and the distance to the object based on the detection results of the distance measurement units 16 and 17. That is, the distance measurement units 16 and 17 are an example of an object detection unit for detecting objects (stationary objects, moving objects) around the vehicle 1. As stationary objects, there are parked vehicles, walls, curbs, street trees, etc., and as moving objects, there are traveling vehicles, bicycles, pedestrians, animals, etc.

[0035] Figure 4 is an exemplary block diagram showing the structure of the control system 100 including the parking assist device according to the embodiment. As Figure 4 illustrated, in addition to the electronic control unit 14, the monitoring device 11, the distance measurement units 16 and 17, etc., the steering system 13, the braking system 18, the steering angle sensor 19, the acceleration sensor 20, the gear position sensor 21, the wheel speed sensor 22, the drive system 23, etc. are electrically connected via the in-vehicle network 26 which is an electrical communication line. The in-vehicle network 26 is configured as, for example, a CAN (Controller Area Network). The electronic control unit 14 can control the steering system 13, the braking system 18, the drive system 23, etc. by sending control signals via the in-vehicle network 26.

[0036] In addition, the electronic control unit 14 can receive the detection results of the torque sensor 13b, the brake sensor 18b, the steering angle sensor 19, the distance measurement units 16 and 17, the acceleration sensor 20, the gear position sensor 21, the wheel speed sensor 22, etc., and the operation signals of the operation input unit 10 via the in-vehicle network 26.

[0037] The steering control system 13 is an electric power steering system, an SBW (Steer By Wire) system, etc. The steering control system 13 has an actuator 13a and a torque sensor 13b. Moreover, the steering control system 13 is electrically controlled by an electronic control unit 14, etc., and by operating the actuator 13a, a torque is applied to the steering control part 4 such as the steering wheel (refer to Figure 1 , Figure 3 ) to supplement the steering force, thereby steering the wheels 3. The torque sensor 13b detects the torque applied by the driver to the steering control part 4 and sends the detection result to the electronic control unit 14.

[0038] The braking system 18 includes an ABS (Anti-lock Brake System) that controls the locking of the brakes of the vehicle 1, a skid prevention device (ESC: Electronic Stability Control) that suppresses the skidding of the vehicle 1 during turning, an electric braking system that enhances the braking force to assist braking, and a BBW (Brake By Wire). The braking system 18 has an actuator 18a and a brake sensor 18b. The braking system 18 is electrically controlled by an electronic control unit 14, etc., and applies a braking force to the wheels 3 via the actuator 18a. The braking system 18 detects signs of brake locking, wheel 3 spinning, and skidding, etc. based on the rotational speed difference between the left and right wheels 3, etc., and performs control to suppress brake locking, wheel 3 spinning, and skidding. The brake sensor 18b is a displacement sensor that detects the position of the brake pedal, which is a movable part of the braking operation part 6, and sends the detection result of the position of the brake pedal to the electronic control unit 14.

[0039] The steering angle sensor 19 is a sensor that detects the steering operation amount of the steering control part 4 such as the steering wheel. The steering angle sensor 19 is composed of a Hall element, etc., detects the rotation angle of the rotating part of the steering control part 4 as the steering operation amount, and sends the detection result to the electronic control unit 14. The acceleration sensor 20 is a displacement sensor that detects the position of the acceleration pedal, which is a movable part of the acceleration operation part 5, and sends the detection result to the electronic control unit 14.

[0040] The gear position sensor 21 is a sensor that detects the position of movable parts such as the lever, arm, buttons, etc. of the gear shift operation part 7, and sends the detection result to the electronic control unit 14. The wheel speed sensor 22 has a Hall element, etc., detects the rotation amount of the wheels 3 and the rotational speed of the wheels 3 per unit time, and sends the detection result to the electronic control unit 14.

[0041] The drive system 23 is an internal combustion engine (engine) system or a motor system as a drive source. The drive system 23 controls the fuel injection amount of the engine, the intake air amount control, and the output value of the motor according to the required operation amount of the driver (user) detected by the acceleration sensor 20. The required operation amount of the driver refers to, for example, the amount of depression of the accelerator pedal. In addition, regardless of the user's operation, the output values of the engine and the motor can be controlled in cooperation with the control of the steering system 13 and the braking system 18 according to the driving state of the vehicle 1. For example, normal driving assistance including parking assistance can be performed.

[0042] In addition, the structures, configurations, electrical connection methods, etc. of the above various sensors and actuators are for example, and various settings or changes can be made.

[0043] The electronic control unit 14 is composed of a computer or the like, and comprehensively manages the control of the vehicle 1 through the cooperation of hardware and software. Specifically, the electronic control unit 14 includes a CPU (Central Processing Unit) 14a, a ROM (Read Only Memory) 14b, a RAM (Random Access Memory) 14c, a display control unit 14d, an audio control unit 14e, and an SSD (Solid State Drive) 14f. The CPU 14a, the ROM 14b, and the RAM 14c may also be provided on the same circuit board.

[0044] The CPU 14a is capable of reading a program installed and stored in a non-volatile storage device (non-transitory storage medium) such as the ROM 14b and performing arithmetic processing according to the program. The ROM 14b stores various programs and parameters required for the execution of the program. The ROM 14b stores a table representing the first deceleration and the second deceleration for each upper limit speed in parking assistance. The ROM 14b is an example of a storage unit. The RAM 14c temporarily stores various data used in the arithmetic operations performed by the CPU 14a. In the arithmetic processing performed by the electronic control unit 14, the display control unit 14d mainly executes image processing on the captured image data acquired from the imaging unit 15 and output to the CPU 14a, conversion of the image data acquired from the CPU 14a into display image data to be displayed on the display devices 8 and 12, etc. In the arithmetic processing performed by the electronic control unit 14, the audio control unit 14e mainly executes processing of the sound acquired from the CPU 14a and output to the audio output device 9. The SSD 14f is a rewritable non-volatile storage unit that continuously stores the data acquired from the CPU 14a even when the power supply of the electronic control unit 14 is cut off. In addition, the CPU 14a, ROM 14b, RAM 14c, etc. can be integrated in the same package. Additionally, the electronic control unit 14 can also be structured to use other logical arithmetic processors, logical circuits, etc., such as a DSP (Digital Signal Processor), instead of the CPU 14a. Additionally, an HDD (Hard Disk Drive) can be provided instead of the SSD 14f, or the SSD 14f and HDD can be provided separately from the electronic control unit 14.

[0045] Figure 5 is an exemplary and schematic block diagram showing the functional structure of the parking assistance device implemented in the control system 100 according to the embodiment. In the electronic control unit 14, the CPU 14a loads the parking assistance program read from the ROM 14b into the RAM 14c and executes it, thereby as Figure 5 shown, implementing a parking assistance device including modules such as a target parking position determination unit 141, a path generation unit 142, a distance calculation unit 143, a target speed setting unit 144, a movement control unit 145, etc.

[0046] In addition, a part or all of the target parking position determination unit 141, path generation unit 142, distance calculation unit 143, target speed setting unit 144, movement control unit 145, etc. can also be constituted by hardware such as a circuit. Additionally, in Figure 5 , although not shown in the figure, the CPU 14a can also implement various modules required for the running of the vehicle 1. Additionally, in Figure 5In this case, the CPU 14a that executes the parking assistance process is mainly shown, but a CPU that includes various modules required for the vehicle 1 to travel may also be provided, and an electronic control unit different from the electronic control unit 14 may also be provided.

[0047] Figure 6 is an exemplary and schematic diagram showing a guidance path R generated in the parking assistance device according to the embodiment. In Figure 6 the example shown, the guidance path R is a path that guides the vehicle 1 entering the parking lot 200 from the guidance start position via the turning-back position RS to the parking area P. Here, the guidance start position is set as, for example, Figure 6 the position of the vehicle 1 shown. In addition, the turning-back position RS is the terminal of the forward guidance path RF and is the forward stop position. In addition, the parking area P is set as the final destination of the vehicle 1 in the parking assistance. Figure 7 is an exemplary and schematic diagram showing a target speed profile L set in the parking assistance device according to the embodiment. In Figure 7 the example shown, the vertical axis represents speed and the horizontal axis represents time. In Figure 7 the example shown, the target speed profile L includes an acceleration line L1, a holding line L2, a first deceleration line L3, and a second deceleration line L4. Figure 7 The exemplified target speed profile L relates to parking assistance when performing reverse guidance from the turning-back position RS toward the target parking position Pt. The guidance start position in the parking assistance during reverse guidance is the turning-back position RS. Hereinafter, each function of the parking assistance device will be described with reference to Figure 6 and Figure 7

[0048] The target parking position determination unit 141 determines the parking area P and the target parking position Pt within the parking area P. Specifically, the target parking position determination unit 141 searches for candidates for the parking area P based on the surrounding information indicating the surrounding conditions of the vehicle 1. In this case, the target parking position determination unit 141 considers the vehicle width and vehicle length of the vehicle 1 and searches for a space that can accommodate the vehicle 1 and ensure a specified margin area in the vehicle width direction and the vehicle length direction as a candidate for the parking area P. The target parking position determination unit 141, for example, starts searching for candidates for the parking area P on the occasion of receiving a request signal for requesting parking assistance. The request signal is output, for example, from the operation input unit 10 or the operation unit 14g (refer to Figure 3 , Figure 4 ) according to the user's operation. For example, the target parking position determination unit 141 searches for candidates for the parking area P while the vehicle 1 is traveling at a low speed within the parking lot 200. As shown in Figure 6 , the target parking position determination unit 141 may also search for candidates for the parking area P while the vehicle 1 is parked within the parking lot 200.

[0049] As peripheral information, it is possible to appropriately utilize the captured image data captured by the imaging unit 15, the distance measurement data measured by the distance measurement units 16 and 17, and the like. The peripheral information such as the captured image data and the distance measurement data can be acquired via the display control unit 14d and the in-vehicle network 26. In addition, the acquisition of the peripheral information using the imaging unit 15, the distance measurement units 16 and 17 can be always executed when the vehicle 1 is started, or can be executed during the period until the parking assistance ends upon receipt of a request signal for parking assistance. Further, the peripheral information can be acquired while the vehicle 1 is moving within the parking lot 200, or can be acquired when the vehicle 1 stops at the guiding start position within the parking lot 200.

[0050] When the target parking position determination unit 141 can acquire candidates for the parking area P, it presents the candidates for the parking area P together with, for example, an aerial image representing the surrounding situation on the display device 8 to allow the driver to select. When there are multiple candidates for the parking area P, the target parking position determination unit 141 can also present all the parking areas P on the display device 8 to allow the driver to select. In this case, the target parking position determination unit 141 can also selectively present the candidates for the parking area P on the display device 8 in the order of the specified priority from high to low. As the order of the priority from high to low, for example, it is possible to appropriately utilize the order of the closest to the current position of the vehicle itself, or the order of the largest space, etc. The driver can express the intention to park by selecting the parking area P presented on the display device 8 by using the operation input unit 10 or the like. Further, even when there is only one candidate for the parking area P, the target parking position determination unit 141 can also display the parking area P on the display device 8 to allow the driver to select and thereby confirm the intention to park.

[0051] In addition, the request signal and the control signal indicating the selection result of the parking area P of the user can also be generated based on the user's voice input, gesture input, and the like.

[0052] When the target parking position determination unit 141 determines that the driver has selected the parking area P where the vehicle is desired to park, it determines the target parking position Pt for moving the vehicle 1 to the selected parking area P. The target parking position Pt is the moving target position when the vehicle 1 is moved to the parking area P. For example, as Figure 6As shown, it can be determined based on the center position Ct of the rear axle of the vehicle 1. The target parking position Pt is set, for example, as a position at a specified distance from the parking reference line PL at the front end of the plurality of white lines 210 connecting the specified parking area P. Therefore, if the vehicle 1 is moved so that the center position Ct of the rear axle coincides with the target parking position Pt, the vehicle 1 can be guided to be accommodated in the parking area P. In addition, the reference position used as a reference when guiding the vehicle 1 may be other than the center position Ct of the rear axle. For example, it may be set as the front end 2c of the vehicle 1. In this case, the target parking position Pt corresponding to the position of the end 2c is set.

[0053] The path generation unit 142 generates a guidance path R based on the target parking position Pt set by the target parking position determination unit 141 and the current position of the vehicle 1. As the guidance path R, for example, a path with the minimum number of reversals that can guide the vehicle 1 from the current position to the target parking position Pt can be used. Here, the current position of the vehicle 1 at the start of guidance is set as the guidance start position. In addition, the calculation of the guidance path R can use well-known techniques, and detailed description is omitted.

[0054] In addition, the parking assist device according to the embodiment parks the vehicle 1 in the parking area P in a substantially reverse posture. Therefore, as Figure 6 shown, the guidance path R guides the vehicle 1 to move forward temporarily from the current position so that the rear of the vehicle 1 faces the entrance of the parking area P, and then makes it reverse. Therefore, the guidance path R includes a forward guidance path RF for guiding the vehicle 1 forward from the guidance start position of the vehicle 1 and a backward guidance path RB for guiding the vehicle 1 backward from the reversal position RS toward the target parking position Pt.

[0055] In addition, the guidance path R may be generated, for example, in an external processing device such as a parking lot management device of the vehicle 1. In this case, the path generation unit 142 sends the position of the vehicle 1 and the target parking position Pt to the external processing device and receives the guidance path R generated there. At this time, the position of the vehicle 1 may also be obtained through a parking lot surveillance camera or the like. In addition, there may be a case where the search for the parking area P is executed in the external processing device and the candidates for the parking area P are received. In addition, the determination of the target parking position Pt may also be executed in the external processing device.

[0056] The distance calculation unit 143 calculates the distance on the guidance path R generated by the path generation unit 142. Specifically, in the stage before the start of guidance, the distance calculation unit 143 calculates the total driving distance of the reverse guidance from the turning-back position RS to the target parking position Pt. As the total driving distance, it is also possible to further calculate the total driving distance of the guidance path R from the guidance start position to the target parking position Pt, and the total driving distance during the forward guidance from the guidance start position to the turning-back position RS. The distance calculation unit 143 calculates the remaining distance DR′, the first driving distance DA, and the second driving distance DB at the deceleration start time t1 based on the target speed profile L set by the target speed setting unit 144. Specifically, the distance calculation unit 143 calculates the remaining distance DR′ at the deceleration start time t1 based on the first deceleration line L3 and the second deceleration line L4. The distance calculation unit 143 calculates the first driving distance DA of the first section decelerating at the first deceleration rate based on the first deceleration line L3. The distance calculation unit 143 calculates the second driving distance DB of the second section decelerating at the second deceleration rate based on the second deceleration line L4. Here, in Figure 7 the example shown, the remaining distance DR′ at the deceleration start time t1 is equal to the sum of the first driving distance DA and the second driving distance DB.

[0057] In addition, in the stage after the start of the reverse guidance, the distance calculation unit 143 calculates the remaining distance DR from an arbitrary position on the guidance path R to the target parking position Pt. The arbitrary position corresponds to Figure 7 the position at an arbitrary time t in the example shown. The distance calculation unit 143 calculates the remaining distance DR based on, for example, the guidance path R and the current position of the vehicle 1. The distance calculation unit 143 calculates the remaining distance DR by, for example, subtracting the driving distance of the vehicle 1 from the turning-back position RS from the total driving distance during the reverse driving. In addition, the remaining distance DR and the remaining distance DR′ are respectively the driving distances that the vehicle 1 travels at that position before reaching the target parking position Pt.

[0058] The target speed setting unit 144 sets, for example, in the stage before the start of the reverse guidance Figure 7The illustrated target speed profile L. The target speed setting unit 144 that sets the target speed profile L is an example of a setting unit. Specifically, the target speed setting unit 144 sets the target speed profile L such that the vehicle 1 decelerates at a first deceleration in a first section and decelerates at a second deceleration in a second section. Here, the first section is between the deceleration start position at the time of reverse guidance and the deceleration change position. In other words, the first section is the range in which the vehicle 1 travels during the period from the deceleration start time t1 to the deceleration change time t2. The deceleration start position is the position on the reverse guidance path RB where the remaining distance DR from the target stop position Pt is the remaining distance DR' (first remaining distance). The remaining distance DR' is, for example, equal to the sum of the first travel distance DA and the second travel distance DB. The deceleration change position is the position where the remaining distance DR from the target stop position Pt is the second travel distance DB (second remaining distance). The second section is between the deceleration change position and the target stop position Pt. In other words, the second section is the range in which the vehicle 1 travels during the period from the deceleration change time t2 to the stop time t3. The target stop position Pt is the target position where the vehicle 1 stops. The second section is a section continuous with the first section. The second deceleration is greater than the first deceleration. The target speed profile L is the target of the vehicle speed of the vehicle 1.

[0059] More specifically, the target speed setting unit 144 sets the upper limit speed Vmax in parking assistance. The target speed setting unit 144, for example, sets the value of the upper limit speed Vmax according to the driving mode set at that time. The upper limit speed Vmax for each driving mode is, for example, preset and stored in the ROM 14b or the like. As the upper limit speed Vmax, for example, it is 5 km / h.

[0060] In addition, the target speed setting unit 144, for example, sets the first deceleration at the first-stage deceleration and the second deceleration at the second-stage deceleration according to the setting of the driving mode. A table showing the first deceleration and the second deceleration for each driving mode is, for example, preset and stored in the ROM 14b or the like. In addition, a table showing the first deceleration and the second deceleration for each upper limit speed Vmax in parking assistance may be stored in the ROM 14b. In this way, the target speed setting unit 144 selects the first deceleration and the second deceleration according to the driving mode selected by the user. In other words, the first deceleration and the second deceleration are selected based on the upper limit speed Vmax determined according to the driving mode selected by the user. As a result, since the first deceleration and the second deceleration corresponding to the driving mode selected by the user are determined, the parking position accuracy can be improved, and it is not likely to cause discomfort to the user such as the driver.

[0061] As the first deceleration, for example, a deceleration that can ensure the followability of the vehicle 1 to the target speed is set. The first deceleration is appropriately set according to the characteristics of the vehicle 1 such as the responsiveness of the drive system 23 and the braking system 18. As the second deceleration, a deceleration that is determined in advance through tests or the like and does not cause a braking shock to the driver or the like is set. In addition, as the second deceleration, a deceleration that is determined in advance through tests or the like and does not cause discomfort such as a feeling of "slow deceleration" to the driver or the like is set. The second deceleration can also be further set according to the characteristics of the vehicle 1 in the same manner as the first deceleration. As the ratio of the first deceleration to the second deceleration, for example, it is 1:2. As the ratio of the time length of the first section of the first deceleration to the time length of the second section of the second deceleration, for example, it is 1:1. In addition, the above ratios can be appropriately set according to the characteristics of the vehicle 1 and the feelings of users such as the driver.

[0062] In addition, the target speed setting unit 144, for example, sets the target speed Vsw at the time of the second-stage transition according to the setting of the driving mode. The target speed Vsw at the time of the second-stage transition for each driving mode is, for example, set in advance and stored in the ROM 14b or the like. As the target speed Vsw at the time of the second-stage transition, a speed greater than the lower limit of the vehicle speed that can ensure the vehicle speed inference accuracy of the vehicle 1 is set. In addition, the target speed Vsw at the time of the second-stage transition is set according to the characteristics of the vehicle 1, for example. As the target speed Vsw at the time of the second-stage transition, for example, it is a vehicle speed of 0.7 km / h to 1 km / h or more. As the target speed Vsw at the time of the second-stage transition, for example, it is 3 km / h.

[0063] In this way, the parking assist device according to the embodiment sets the target speed pattern L in the stage before the start of the reverse guidance. In addition, as the target speed pattern L generated before the start of the guidance of the vehicle 1, it does not need to be a time series of the target speed, and it is only necessary to be information indicating each deceleration and the timing of switching the deceleration.

[0064] In addition, the target speed setting unit 144 performs braking drive control of the vehicle 1 in the stage after the start of the reverse guidance, based on the set target speed pattern L and the vehicle speed of the vehicle 1 obtained from the output of the wheel speed sensor 22. The target speed setting unit 144 that performs braking drive control is an example of a control unit. Specifically, the target speed setting unit 144 generates a control signal indicating acceleration, maintenance, or deceleration of the vehicle speed of the vehicle 1 in such a manner that the vehicle speed of the vehicle 1 follows the target speed pattern L, and supplies the generated control signal to the movement control unit 145. The target speed setting unit 144 is as follows Figure 7When guiding the vehicle 1 along the reverse guiding path RB as shown, for example, the vehicle 1 stopped at the turning-back position RS is accelerated to the upper limit speed Vmax (acceleration line L1) in the parking assistance at a prescribed acceleration. Here, the turning-back position RS is the guiding start position in the parking assistance during reverse guiding. After that, the target speed setting unit 144 maintains the prescribed upper limit speed Vmax (holding line L2). Then, the target speed setting unit 144 decelerates the speed from the upper limit speed Vmax to the target speed Vsw at the second-stage transition at the first deceleration rate (first deceleration line L3). Further, the target speed setting unit 144 decelerates the speed from the target speed Vsw at the second-stage transition to zero speed at the second deceleration rate to stop the vehicle 1 at the target parking position Pt (second deceleration line L4).

[0065] The movement control unit 145 executes various controls for guiding the vehicle 1 along the guiding path R. In the case of guiding the vehicle 1 along the guiding path R in the present embodiment, for example, the movement control unit 145 executes full automatic control for automatically controlling all of the steering system 13, the braking system 18, the drive system 23, etc., or semi-automatic control for automatically controlling a part of the controls of the steering system 13, the braking system 18, the drive system 23, etc. In addition, the movement control unit 145 can also provide operation guidance for the steering system 13, the braking system 18, the drive system dashboard 24, etc. to the driver in such a manner that the vehicle 1 can move along the guiding path R, and execute manual control for the driver to perform driving operations.

[0066] In the present embodiment, as an example, the case of guiding the vehicle 1 by full automatic control will be described. The movement control unit 145 controls the drive system 23 to adjust the engine output or the motor output in such a manner that the vehicle 1 smoothly moves along the guiding path R without sudden acceleration or sudden deceleration according to the control signal supplied from the target speed setting unit 144. The movement control unit 145 controls the braking system 18 to adjust the braking generation timing and the braking force in such a manner that the vehicle 1 smoothly moves along the guiding path R without sudden acceleration or sudden deceleration according to the control signal supplied from the target speed setting unit 144. The movement control unit 145 controls the steering system 13 to control the steering angle in such a manner that the vehicle 1 advances along the guiding path R.

[0067] An example of the operation during reverse guiding of the parking assistance device configured as above will be described with reference to the drawings. Figure 8 It is a flowchart showing an example of the parking assistance process during reverse guiding executed in the parking assistance device according to the embodiment. In addition, in Figure 8In the flowchart, an example is described in which, after the vehicle 1 enters the parking lot 200, the search for the parking area P is automatically performed, and the vehicle 1 stopped at the guiding start position is automatically guided to the selected parking area P to complete parking.

[0068] The target parking position determination unit 141 determines the parking area P and the target parking position Pt (S101). The path generation unit 142 generates a guiding path R for guiding the vehicle 1 from the guiding start position to the target parking position Pt (S102). The distance calculation unit 143 calculates the total moving distance based on the generated guiding path R (S103). The total moving distance is the distance from the guiding start position to the target parking position Pt.

[0069] After that, the target speed setting unit 144 sets the upper limit speed Vmax during parking assistance (S104). In addition, the target speed setting unit 144 sets the first deceleration during the first-stage deceleration (S105), and sets the second deceleration during the second-stage deceleration (S106). In addition, the target speed setting unit 144 sets the target speed Vsw during the second-stage transition (S107).

[0070] After that, the target speed setting unit 144 starts guiding the vehicle 1 (S108). The target speed setting unit 144 starts guiding the vehicle 1, for example, when the driver releases the brake pedal. The situation where the driver releases the brake pedal is detected based on the control signal output by the brake sensor 18b. Specifically, the target speed setting unit 144 generates a control signal indicating the acceleration of the vehicle speed of the vehicle 1 in such a way that the vehicle 1 starts to accelerate along the acceleration line L1, and supplies the generated control signal to the movement control unit 145.

[0071] After the backward guiding of the vehicle 1 starts, the distance calculation unit 143 starts calculating the remaining distance DR from the current position of the vehicle 1 to the target parking position Pt (S109). In addition, the target speed setting unit 144 calculates the first traveling distance DA during the first-stage deceleration and the second traveling distance DB during the second-stage deceleration based on the upper limit speed Vmax and each deceleration (S110, S111). In addition, the first traveling distance DA and the second traveling distance DB may be stored in the above table together with the respective decelerations as pre-calculated values.

[0072] In addition, the target speed setting unit 144 accelerates along the acceleration line L1 to confirm whether it can reach the upper limit speed Vmax before the position of the remaining distance DR'. That is, the target speed setting unit 144 confirms whether the sum of the driving distances in the section of decelerating from the upper limit speed Vmax along the first deceleration line L3 (the first driving distance DA), the driving distance in the section of decelerating from the target speed Vsw at the second-stage transition along the second deceleration line L4 (the second driving distance DB), and the driving distance in the section of accelerating from the turning-back position RS along the acceleration line L1 to the upper limit speed Vmax is within the total driving distance calculated in the process of S103. The turning-back position RS is the guiding start position in the parking assistance during reverse guiding. When the sum of the first driving distance DA, the second driving distance DB, and the driving distance in the section of accelerating along the acceleration line L1 is less than or equal to the total driving distance, the target speed setting unit 144 sets the section from the target parking position Pt to the position of the remaining distance DR' at the deceleration start time t1 as the deceleration section. More specifically, the section from the target parking position Pt to the position where the target speed is the target speed Vsw at the second-stage transition is set as the section of decelerating along the second deceleration line L4. In addition, the section from the position where the target speed is the target speed Vsw at the second-stage transition to the position of the remaining distance DR' at the deceleration start time t1 is set as the section of decelerating along the first deceleration line L3. After that, the target speed setting unit 144 sets the section of accelerating along the acceleration line L1 and sets the remaining section as the section of driving at a constant speed along the holding line L2. In this way, as Figure 7 illustrated, the target speed setting unit 144 generates a target speed profile L for decelerating the vehicle 1 with at least two deceleration rates.

[0073] The target speed setting unit 144 determines whether the remaining distance DR at this moment is greater than the sum of the first driving distance DA and the second driving distance DB (the first remaining distance) (S112). In other words, the target speed setting unit 144 determines whether the remaining distance DR is greater than the remaining distance DR'. Here, when the remaining distance DR is greater than the remaining distance DR', it means that the vehicle 1 has not reached the deceleration start position during reverse guiding. When the remaining distance DR is greater than the remaining distance DR' (S112: Yes), the target speed setting unit 144 accelerates or drives the vehicle 1 at a constant speed according to the remaining distance DR at this moment (S113). Specifically, the target speed setting unit 144 generates a control signal for making the vehicle speed of the vehicle 1 follow the acceleration line L1 or the holding line L2 according to the remaining distance DR at this moment, and supplies the generated control signal to the movement control unit 145.

[0074] When the remaining distance DR is less than or equal to the remaining distance DR' (S112: No), the target speed setting unit 144 determines whether the remaining distance DR is greater than the second traveling distance DB (second remaining distance) (S114). Here, when the remaining distance DR is greater than the second traveling distance DB, it means that the vehicle speed of the vehicle 1 is greater than the target speed Vsw at the second-stage transition. In other words, in S114, the target speed setting unit 144 determines whether it is the first section in which the vehicle 1 decelerates at the first deceleration. When the remaining distance DR is greater than the second traveling distance DB (S114: Yes), the target speed setting unit 144 decelerates the vehicle 1 at the first deceleration (S115). Specifically, the target speed setting unit 144 generates a control signal for making the vehicle speed of the vehicle 1 follow the first deceleration line L3, and supplies the generated control signal to the movement control unit 145.

[0075] When the remaining distance DR is less than or equal to the second traveling distance DB (S114: No), the target speed setting unit 144 decelerates the vehicle 1 at the second deceleration (S116). Here, the remaining distance DR being less than or equal to the second traveling distance DB means the second section in which the vehicle 1 decelerates at the second deceleration. Specifically, the target speed setting unit 144 generates a control signal for making the vehicle speed of the vehicle 1 follow the second deceleration line L4, and supplies the generated control signal to the movement control unit 145. After that, when the remaining distance DR becomes zero, the target speed is set to 0, and the guidance of the vehicle 1 during reverse guidance is ended.

[0076] In this way, the parking assist device according to the embodiment decelerates the vehicle 1 at the second deceleration after decelerating it at the first deceleration. Thereby, it is possible to improve the followability of the actual speed of the vehicle 1 with respect to the target speed in the braking drive control for automatic parking. That is, according to the technology of the embodiment, it is possible to improve the parking position accuracy in the braking drive control for automatic parking.

[0077] Figure 9 It is an exemplary and schematic diagram showing the target speed graph L set when the target speed Vs at the deceleration start time t1 does not satisfy the upper limit speed Vmax in the parking assist in the parking assist device according to the embodiment. In Figure 9 the example shown, the vertical axis represents speed and the horizontal axis represents time. In Figure 9 the example shown, the target speed graph L includes an acceleration line L1, a first deceleration line L3, and a second deceleration line L4. In Figure 8 the process of S111, the target speed setting unit 144 in the traveling distance of the section where it decelerates along the first deceleration line L3 from the upper limit speed Vmax ( Figure 7The first travel distance DA), the travel distance of the section where the target speed Vsw at the time of transition from the second stage decelerates along the second deceleration line L4 ( Figure 7 The second travel distance DB), and the sum of the travel distances of the section where the vehicle accelerates to the upper limit speed Vmax along the acceleration line L1 is greater than the total travel distance, as Figure 9 shown, the section where the vehicle accelerates along the acceleration line L1 and the first section are adjusted. Specifically, the target speed setting unit 144 adjusts the section where the vehicle accelerates along the acceleration line L1 and the first section such that the sum of the travel distance when accelerating along the acceleration line L1 and the travel distance after the start of deceleration is within the total travel distance calculated in the process of S103. Therefore, Figure 9 The target speed graph L of Figure 7 becomes a form that shifts the target speed graph L of Figure 9 to the left side of the paper surface within the total travel distance calculated in the process of S103. That is, Figure 7 The first travel distance DA of

[0078] Figure 10 is an exemplary and schematic diagram showing the target speed graph L set when the target speed Vs at the deceleration start time t1 does not satisfy the target speed Vsw at the time of transition to the second stage in the parking assist device according to the embodiment. In Figure 10 the example shown, the vertical axis represents speed and the horizontal axis represents time. In Figure 10 the example shown, the target speed graph L includes the acceleration line L1 and the second deceleration line L4. In Figure 8 In the process of S111 of Figure 7 when the remaining distance DR at the deceleration change time t2, that is, the travel distance of the section where the target speed Vsw at the time of transition to the second stage decelerates along the second deceleration line L4 ( Figure 7 The second travel distance DB of Figure 10 and the sum of the travel distances of the section where the vehicle accelerates to the upper limit speed Vmax along the acceleration line L1 is greater than the total travel distance, as Figure 10 shown, the first travel distance DA is set to zero, and the section where the vehicle accelerates along the acceleration line L1 and the second section are adjusted. Specifically, the target speed setting unit 144 adjusts the section where the vehicle accelerates along the acceleration line L1 and the second section such that the sum of the travel distance when accelerating along the acceleration line L1 and the travel distance of the second section decelerating at the second deceleration is within the total travel distance calculated in the process of S103. Therefore, Figure 9 The target speed graph L of Figure 10the second travel distance DB is less than Figure 7 and Figure 9 the second travel distance DB.

[0079] In this way, when the total travel distance of the backward guidance from the return position RS to the target parking position Pt involved in the embodiment is short, by setting (changing) the travel distance of the first section to be short, two-stage deceleration is thus performed. In other words, when the total travel distance of the backward guidance from the return position RS to the target parking position Pt is short, the target speed profile is set in such a way that deceleration starts at a remaining distance smaller than the remaining distance DR′ (the first remaining distance) and larger than the second travel distance DB (the second remaining distance) at the first deceleration rate. At this time, the parking assist device does not change the second travel distance DB (the second remaining distance). According to this structure, the parking position accuracy can be improved by two-stage deceleration. Here, when the total travel distance of the backward guidance from the return position RS to the target parking position Pt is short, since the first section set in consideration of the vehicle speed followability becomes shorter, there is a concern that the vehicle speed followability becomes lower. However, when the total travel distance of the backward guidance from the return position RS to the target parking position Pt is short, the speed change caused by acceleration or deceleration is also small, so the influence caused by the decrease in followability is small. In addition, when the total travel distance of the backward guidance from the return position RS to the target parking position Pt involved in the embodiment is so short that two-stage deceleration cannot be performed, since the influence caused by the decrease in followability is small, one-stage deceleration with one deceleration rate is performed.

[0080] In addition, in the present embodiment, as Figure 7 illustrated, the braking drive control during backward guidance is mainly described, but it is not limited thereto. The technology involved in the embodiment can also be applied to the forward guidance for guiding the vehicle 1 from the guidance start position to the return position RS, and can also be applied to both forward guidance and backward guidance. In addition, as the guidance path R, it can be either the forward guidance path RF or the backward guidance path RB. Even with the above structure, the same effect as above can be obtained.

[0081] In addition, in the present embodiment, as Figure 7 illustrated, the case of performing two-stage deceleration using two deceleration rates is illustrated, but it is not limited thereto. Multi-stage deceleration of three or more stages can also be performed. Even with this structure, the same effect as above can be obtained.

[0082] In the present embodiment, as described above, the timing (deceleration start time t1) to start decelerating at the first deceleration rate is defined by the remaining distance DR on the guiding path R (forward guiding path RF and / or backward guiding path RB). As this deceleration start time t1, for example, the timing when the vehicle body of the vehicle 1 intrudes into the parking area P can be used. In this case, as the remaining distance DR' at the deceleration start time t1, for example, it is the distance between the parking reference line PL and the target parking position Pt. In other words, as the remaining distance DR' at the deceleration start time t1, for example, the distance between the front end 2c of the vehicle 1 and the center position Ct of the rear wheel axle can be used. With this structure, the remaining distance DR' at the deceleration start time t1 can be predefined according to the size of the vehicle 1. Additionally, for example, even when the current position of the vehicle 1 is obtained through image processing, the deceleration start time t1 can be determined based on the white line 210 and the parking reference line PL with relatively high recognition accuracy in the image processing, and thus there is an effect of suppressing the degradation of the parking position accuracy.

[0083] As mentioned above, embodiments of the present invention have been illustrated. However, the above embodiments and modification examples are merely examples and are not intended to limit the scope of the invention. The above embodiments and modification examples can be implemented in various other ways, and various omissions, substitutions, combinations, and changes can be made without departing from the gist of the invention. Additionally, the structures and shapes of each embodiment and each modification example can also be implemented with partial replacements.

Claims

1. A parking assist device comprising an electronic control unit (14), wherein: The electronic control unit (14) sets a target speed pattern as a target speed of the vehicle (1) in the following manner: after accelerating the vehicle (1) at a predetermined acceleration from a guidance start position, the vehicle (1) is decelerated at a first deceleration while the remaining distance from a target position for parking the vehicle (1), i.e., a target parking position, is from a first remaining distance to a second remaining distance smaller than the first remaining distance, and the vehicle (1) is decelerated at a second deceleration larger than the first deceleration while the remaining distance from the second remaining distance to the target parking position is from the first remaining distance. The electronic control unit (14) performs braking and driving control of the vehicle (1) based on the target speed graph. By the braking drive control based on the target speed graph, the electronic control unit (14) sets the target speed graph in such a manner that deceleration is performed at the first deceleration from a position having a remaining distance smaller than the first remaining distance and larger than the second remaining distance when the sum of the travel distance when the vehicle (1) is accelerated at the prescribed acceleration, the travel distance when the vehicle (1) is decelerated at the first deceleration, and the travel distance when the vehicle (1) is decelerated at the second deceleration is greater than the distance from the guidance start position to the target parking position.

2. The parking assist device according to claim 1, wherein: The vehicle further includes a storage unit storing a table indicating the first deceleration rate and the second deceleration rate for each upper speed limit in parking assistance.

3. The parking assist device according to claim 1 or 2, wherein: The electronic control unit (14) includes a storage unit that stores a table indicating the first deceleration and the second deceleration for each upper speed limit in parking assistance.

4. The parking assist device according to claim 1 or 2, wherein: The electronic control unit (14) selects the first deceleration and the second deceleration according to a driving mode.

5. A parking assistance method, wherein: The steps include: A target speed graph for a vehicle (1) is set in the following manner: after accelerating the vehicle (1) at a predetermined acceleration from a guidance start position, the vehicle (1) is decelerated at a first deceleration rate while the remaining distance from a target position for parking the vehicle (1), i.e., a target parking position, is from a first remaining distance to a second remaining distance smaller than the first remaining distance; and the vehicle (1) is decelerated at a second deceleration greater than the first deceleration rate while the remaining distance from the second remaining distance to the target parking position is from a first remaining distance to a second remaining distance smaller than the first remaining distance. and performing braking and driving control of the vehicle (1) based on the target speed graph, By the braking drive control based on the target speed graph, when the sum of the travel distance when the vehicle (1) is accelerated at the prescribed acceleration, the travel distance when the vehicle (1) is decelerated at the first deceleration, and the travel distance when the vehicle (1) is decelerated at the second deceleration is greater than the distance from the guidance start position to the target parking position, the target speed graph is set in such a manner that deceleration is performed at the first deceleration starting from a position with a remaining distance smaller than the first remaining distance and larger than the second remaining distance.

6. A non-transitory storage medium storing instructions executable by one or more processors and causing the one or more processors to perform the following functions: A target speed graph for the vehicle (1) is set in such a manner that after accelerating the vehicle (1) at a predetermined acceleration from a guidance start position, the vehicle (1) is decelerated at a first deceleration rate while the remaining distance from a target position for parking the vehicle (1), i.e., a target parking position, is from a position of a first remaining distance to a position of a second remaining distance smaller than the first remaining distance, and the vehicle (1) is decelerated at a second deceleration larger than the first deceleration rate while the remaining distance from the position of the second remaining distance to the target parking position; and performing braking and driving control of the vehicle (1) based on the target speed graph, By the braking drive control based on the target speed graph, when the sum of the travel distance when the vehicle (1) is accelerated at the prescribed acceleration, the travel distance when the vehicle (1) is decelerated at the first deceleration, and the travel distance when the vehicle (1) is decelerated at the second deceleration is greater than the distance from the guidance start position to the target parking position, the target speed graph is set in such a manner that deceleration is performed at the first deceleration starting from a position with a remaining distance smaller than the first remaining distance and larger than the second remaining distance.

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