Automatic parking system

Abstract

To provide an automatic parking device which is improved to have higher capability to reduce risks of abrupt reduction in a vehicle speed and vibrationally fluctuation than that in conventional devices even in a situation where creep force is tentatively increased with drive force of a vehicle tentatively increased.SOLUTION: An automatic parking device includes a control device which calculates: target acceleration or deceleration Gt of a vehicle on the basis of a remaining distance to a target parking position; and demand deceleration Gbd on the basis of a sum of the target acceleration or deceleration and added deceleration Gc corresponding to creep force Fvc. The control device limits a change rate of the added deceleration to a limit change rate Rlim (S90), calculates the demand deceleration Gbd on the basis of the sum of the target acceleration or deceleration Gt and the added deceleration Gac after limitation (S110 and S120), and variably sets the limit change rate Rlim on the basis of information around the vehicle, a positional relation between the target parking position and the vehicle, and a travel state of the vehicle so that the limit change rate Rlim is increased as a change in the acceleration or deceleration of the vehicle is increased (S80).SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present invention relates to an automatic parking device for a vehicle such as an automobile. [Background technology]

[0002] There is known an automatic parking device that is configured to display image information of the vehicle's surroundings obtained by a camera sensor or the like on a display, and when a target parking position is determined by the occupant based on the image information, move the vehicle to the target parking position by automatic driving.

[0003] For example, the following Patent Document 1 describes an automatic parking device that is configured to automatically move the vehicle to a target parking position and park it without causing the vehicle to behave unnaturally, even if an unknown disturbance occurs that hinders the vehicle's progress.

[0004] According to an automatic parking device such as that described in Patent Document 1 below, a vehicle is automatically moved and parked, so that the vehicle can be parked in a desired parking position without the driver having to perform any driving operation. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2020-015402 A Summary of the Invention

[0006] [Problem to be solved by the invention] When a vehicle is automatically moved and parked by an automatic parking device, the vehicle may pass over a step or the like. In such a case, the driving force of the vehicle is temporarily increased, and immediately after that the vehicle enters a non-accelerating state, so the creep force temporarily increases. Since the target deceleration during automatic driving must be a value that cancels out the vehicle acceleration equivalent to the creep force, if the creep force temporarily increases, the target deceleration also temporarily increases.

[0007] In conventional automatic parking devices, the target deceleration temporarily increases in response to a temporary increase in creep force, which not only causes the vehicle deceleration to temporarily increase and the vehicle speed to suddenly decrease, but also causes the vehicle speed to fluctuate in an oscillatory manner due to a delayed response of the braking device, reducing the ride comfort of the vehicle.

[0008] The main objective of the present invention is to provide an improved automatic parking device that can reduce the risk of a sudden drop in vehicle speed or vibrational fluctuations compared to conventional devices, even in situations where the vehicle's driving force temporarily increases and the creep force temporarily becomes large. [Means for solving the problems and effects of the invention]

[0009] According to the present invention, a surrounding information acquisition device (16) acquires information about the surroundings of a vehicle (102), and based on the information about the surroundings of the vehicle acquired by the surrounding information acquisition device, a target trajectory (112) of the vehicle to a target parking position is set, a target acceleration / deceleration (Gt) of the vehicle is calculated based on a remaining distance (L) to the target parking position along the target trajectory, a required acceleration (Gad) for a drive device (22) is calculated based on the target acceleration / deceleration, and a required acceleration (Gad) for the drive device is calculated based on the target acceleration / deceleration. The driving force is temporarily increased, An automatic parking device (100) is provided, which includes a control device (driving assistance ECU 10) configured to calculate a required deceleration (Gbd) for a braking device (32) based on the sum of a generated creep force (Fvc) and a corresponding additional deceleration (Gc).

[0010] The control device (driving assistance ECU 10) is configured to modify the added deceleration by limiting the rate of change of the added deceleration (Gc) with the limited change rate (Rlim) and to calculate the required deceleration based on the sum of the target acceleration / deceleration and the corrected added deceleration (Gac). Furthermore, the control device is configured to variably set (S80) the limited change rate based on information about the surroundings of the vehicle acquired by the surrounding information acquisition device (16), the positional relationship of the vehicle with respect to the target parking position, and the driving conditions of the vehicle so that the greater the change in the acceleration / deceleration of the vehicle, the greater the limited change rate.

[0011] According to the above configuration, the additional deceleration is corrected by limiting the rate of change of the additional deceleration by the limited rate of change, and the required deceleration is calculated based on the sum of the target acceleration / deceleration and the corrected additional deceleration. Therefore, even when the vehicle passes over a step or the like, a sudden increase in the additional deceleration is suppressed, and a sudden increase in the required deceleration is suppressed. Therefore, the deceleration of the vehicle temporarily increases. Things to do This not only prevents a sudden drop in vehicle speed due to the braking system, but also reduces the risk of the vehicle speed fluctuating violently due to delayed response of the braking system, thereby reducing the risk of a decrease in the ride comfort of the vehicle.

[0012] In addition, according to the above configuration, the limit change rate is variably set based on the information on the surroundings of the vehicle acquired by the surrounding information acquisition device, the positional relationship of the vehicle to the target parking position, and the running conditions of the vehicle so that the limit change rate is increased as the change in the acceleration / deceleration of the vehicle increases. Therefore, the limit change rate can be variably set according to the conditions when the vehicle is automatically parked. For example, the larger the change in the acceleration / deceleration of the vehicle is and the greater the need to stop the vehicle, the larger the limit change rate can be set, and the vehicle can be effectively decelerated and stopped while suppressing a decrease in the ride comfort of the vehicle. Conversely, the smaller the change in the acceleration / deceleration of the vehicle is and the greater the need to ensure the ride comfort of the vehicle, the smaller the limit change rate can be set to ensure good ride comfort of the vehicle.

[0013] In the above description, in order to facilitate understanding of the present invention, the names and / or symbols used in the embodiments described below are added in parentheses to the configurations of the invention corresponding to those embodiments. However, each component of the present invention is not limited to the components of the embodiments corresponding to the names and / or symbols added in parentheses. Other objects, other features, and associated advantages of the present invention will be easily understood from the description of the embodiments of the present invention described below with reference to the drawings. [Brief description of the drawings]

[0014] [Figure 1] 1 is a schematic diagram showing an embodiment of an automatic parking device according to the present invention; [Diagram 2] 4 is a flowchart showing an automatic parking control routine in the embodiment. [Diagram 3] 3 is a flowchart showing a subroutine for controlling acceleration / deceleration during automatic driving in step 50 of the flowchart shown in FIG. 2. [Figure 4] 4 is a flowchart showing a subroutine for setting a limit change rate in step 80 of the flowchart shown in FIG. 3. [Diagram 5] FIG. 13 is a diagram showing an example of a left side overhead image showing the current position of a vehicle; [Figure 6] FIG. 13 is a diagram showing an example of a left-side overhead image in which a target route is set. [Figure 7] 1A to 1C are diagrams illustrating various situations when a vehicle moves to a target parking position. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0015] An automatic parking device according to an embodiment of the present invention will be described in detail below with reference to the accompanying drawings.

[0016] <Configuration> As shown in Fig. 1, an automatic parking device 100 according to an embodiment of the present invention is applied to a vehicle 102 and includes a driving assistance ECU 10. The vehicle 102 includes a drive ECU 20, a braking ECU 30, an electric power steering ECU 40, and a meter ECU 50. The ECU stands for an electronic control unit having a microcomputer as a main part. In the following description, the electric power steering is referred to as EPS.

[0017] The microcomputer of each ECU includes a CPU, ROM, RAM, a readable / writable non-volatile memory (N / M), and an interface (I / F). The CPU realizes various functions by executing instructions (programs, routines) stored in the ROM. Furthermore, these ECUs are connected to each other via a Controller Area Network (CAN) 104 so that they can exchange data (communicate). Therefore, the detection values ​​of sensors (including switches) connected to a specific ECU are also sent to other ECUs.

[0018] The driving assistance ECU 10 is a central control device that performs driving assistance control such as automatic parking control, lane keeping control, etc. In the embodiment, the driving assistance ECU 10 cooperates with other ECUs to perform automatic parking control for automatically moving and parking the vehicle 102 to a target parking position, as will be described in detail later.

[0019] The driving assistance ECU 10 is connected to a camera sensor 12 and a radar sensor 14. The camera sensor 12 and the radar sensor 14 each include a plurality of camera devices and a plurality of radar devices. The camera sensor 12 and the radar sensor 14 function as a surrounding information detection device 16 that detects target information around the vehicle 102.

[0020] Although not shown in the figure, each camera device of the camera sensor 12 includes a camera unit that captures the surroundings of the vehicle 102, and a recognition unit that analyzes image data captured by the camera unit to recognize targets such as white lines on the road and other vehicles. The recognition unit supplies information about the recognized targets to the driving assistance ECU 10 at predetermined time intervals. Note that a LiDAR (Light Detection And Ranging) may be used instead of the camera sensor 12.

[0021] Each radar device of the radar sensor 14 includes a radar transmitting / receiving unit and a signal processing unit (not shown), and the radar transmitting / receiving unit emits millimeter wave band radio waves (hereinafter referred to as "millimeter waves") and receives millimeter waves (i.e., reflected waves) reflected by a three-dimensional object (e.g., another vehicle, a bicycle, a guardrail, etc.) present within the emission range. The signal processing unit acquires information indicating the distance between the vehicle and the three-dimensional object, the relative speed between the vehicle and the three-dimensional object, the relative position (direction) of the three-dimensional object with respect to the vehicle, etc., based on the phase difference between the transmitted millimeter wave and the received reflected wave, the attenuation level of the reflected wave, and the time from transmitting the millimeter wave to receiving the reflected wave, and supplies the information to the driving assistance ECU 10 at predetermined time intervals.

[0022] Furthermore, a setting operation device 18 is connected to the driving assistance ECU 10, and the setting operation device 18 is provided at a position where it can be operated by the driver. Although not shown in Fig. 1, the setting operation device 18 includes an automatic parking switch, and the driving assistance ECU 10 executes automatic parking control when the automatic parking switch is on.

[0023] A drive device 22 that accelerates the vehicle 102 by applying a drive force to drive wheels not shown in Fig. 1 is connected to the drive ECU 20. The drive ECU 20 normally controls the drive device 22 so that the drive force generated by the drive device 22 changes according to the driving operation by the driver, and when a command signal is received from the driving assistance ECU 10, controls the drive device 22 based on the command signal. Signals indicating information detected by various sensors provided in the drive device 22 are input to the drive ECU 20, and the drive ECU 20 calculates a creep force Fvc, which is the drive force of the vehicle generated by the drive device 22 when the vehicle is not driven, based on the information.

[0024] The drive device 22 is not limited to a combination of an internal combustion engine and an automatic transmission. That is, the drive device 22 may be any drive device known in the art, such as a combination of an internal combustion engine and a continuously variable transmission, a so-called hybrid system which is a combination of an internal combustion engine and a motor, a so-called plug-in hybrid system, a combination of a fuel cell and a motor, or a motor.

[0025] A braking device 32 that applies braking force to wheels (not shown in Fig. 1) to decelerate the vehicle 102 is connected to the braking ECU 30. The braking ECU 30 normally controls the braking device so that the braking force generated by the braking device 32 varies according to the braking operation by the driver, and when it receives a command signal from the driving assistance ECU 10, it controls the braking device 32 based on the command signal to perform automatic braking. When braking force is applied to the wheels, brake lights (not shown in Fig. 1) are turned on.

[0026] An EPS device 42 is connected to the EPS-ECU 40. The EPS-ECU 40 controls the EPS device 42 in a manner known in the art based on the steering torque Ts and vehicle speed V detected by a driving operation sensor 60 and a vehicle state sensor 70 described below, thereby controlling the steering assist torque and reducing the steering burden on the driver. The EPS-ECU 40 also controls the EPS device 42 to steer the steered wheels as necessary. Thus, the EPS-ECU 40 and the EPS device 42 function as a steering device that automatically steers the steered wheels as necessary.

[0027] A touch panel type display 52 that displays the status of control by the driving assistance ECU 10 is connected to the meter ECU 50. The display 52 may be, for example, a multi-information display that displays meters and various information, or may be a display of a navigation device 80 described below. As described below, when the display 52 receives a command signal from the driving assistance ECU 10, it displays an image of the surroundings of the vehicle 102 for selecting a parking position, a switch for starting automatic parking, and the like.

[0028] The driving operation sensor 60 and the vehicle condition sensor 70 are connected to the CAN 104. Information detected by the driving operation sensor 60 and the vehicle condition sensor 70 (called sensor information) is transmitted to the CAN 104. The sensor information transmitted to the CAN 104 can be used appropriately in each ECU. Note that the sensor information may be information of a sensor connected to a specific ECU and transmitted to the CAN 104 from the specific ECU.

[0029] The driving operation sensor 60 includes a driving operation amount sensor that detects the amount of operation of the accelerator pedal, a braking operation amount sensor that detects the master cylinder pressure or the depression force on the brake pedal, and a brake switch that detects whether the brake pedal is operated. Furthermore, the driving operation sensor 60 includes a steering angle sensor that detects the steering angle θ, a steering torque sensor that detects the steering torque Ts, etc.

[0030] The vehicle condition sensor 70 includes a vehicle speed sensor that detects the vehicle speed V of the vehicle 102, a longitudinal acceleration sensor that detects the longitudinal acceleration of the vehicle, a lateral acceleration sensor that detects the lateral acceleration of the vehicle, and a yaw rate sensor that detects the yaw rate of the vehicle.

[0031] In this embodiment, the ROM of the driving assistance ECU 10 stores an automatic parking control program corresponding to the flowcharts shown in Figures 2 to 4. The CPU of the driving assistance ECU 10 executes the automatic parking control in accordance with this program.

[0032] <Automatic parking control program (Fig. 2)> Next, an automatic parking control program in the embodiment will be described with reference to the flowchart shown in Fig. 2. The automatic parking control according to the flowchart shown in Fig. 2 is executed by the CPU of the driving assistance ECU 10 when the automatic parking switch is on.

[0033] First, in step S10, the CPU displays an all-around overhead image of the vehicle 102 on the display 52. ​​As shown in Fig. 5, the driver can display a left-side overhead image, a right-side overhead image, a front-side overhead image, and a rear-side overhead image by touching an image selection icon 52A. Fig. 5 is an example of the left-side overhead image 106, and 102n indicates the current position of the vehicle 102.

[0034] In step S20, the CPU judges whether or not the driver has decided on a desired parking position (target parking position) by touching a possible parking position (parking space) displayed on the display 52. ​​If the CPU judges negative, the control returns to step S10, and if the CPU judges positive, the control proceeds to step S30. After deciding on the desired parking position, the driver may get off the vehicle 102 and thereafter operate the terminal device to give necessary instructions regarding remote parking.

[0035] In step S30, the CPU sets a target trajectory from the current position of the vehicle 102 to the target parking position, and displays the target trajectory on the display 52, as well as a "parking start" icon 52B. Fig. 6 shows an example of the left overhead image 106 in which the target trajectory has been set. In Fig. 6, 110 indicates a parking space, and 110A and 110B indicate available parking spaces.

[0036] Assume that the driver touches the portion 110B to determine the parking section 110B as the desired parking position (target parking position). A target trajectory 112 from the current position 102n of the vehicle 102 to the turning point Pr and the reference position Pp of the target parking position 110B is set as a target trajectory of the reference position Pn, and the target trajectory 112 is displayed on the display 52.

[0037] In step S40, the CPU determines whether or not autonomous driving of the vehicle 102 is permitted by touching the "Start Parking" icon 52B displayed on the display 52. ​​If the CPU determines that the vehicle 102 is not parked, it repeatedly executes step S40, and if the CPU determines that the vehicle 102 is parked, it advances the control to step S50.

[0038] In step S50, the CPU, in cooperation with other ECUs, moves the vehicle 102 along the target trajectory toward the target parking position by automatic driving that automatically controls the drive device 22, the brake device 32, and the EPS device 42. Although not shown in the figure, the vehicle 102 can be stopped as necessary by touching a "stop" icon displayed on the display 52. ​​Furthermore, the acceleration / deceleration control of the automatic driving is performed according to the subroutine flowchart shown in Fig. 3, and the steering control of the automatic driving is performed by automatically controlling the EPS device 42 in a manner known in the art so that the vehicle 102 moves along the target trajectory.

[0039] In step S130, the CPU determines whether or not the vehicle 102 has reached the target parking position based on the detection results of the camera sensor 14 and the radar sensor 16. If the CPU determines that the vehicle 102 has reached the target parking position, the CPU returns this control to step S50, and if the CPU determines that the vehicle 102 has reached the target parking position, the CPU advances this control to step S140.

[0040] In step S140, the CPU displays on the display 52 that the vehicle 102 has reached the target parking position, shifts the transmission shift position to the P range, and turns off the ignition switch (IGSW). In the case of remote parking, the display of the terminal device displays that the vehicle 102 has reached the target parking position.

[0041] As can be seen from the above description, when the automatic parking control is started by the automatic parking control switch, an overhead image of the surroundings of the vehicle 102 is displayed (S10). When the driver determines a target parking position using the overhead image (S20), a target trajectory from the current position of the vehicle 102 to the target parking position is set, and the target trajectory and the "Start parking" icon 52A are displayed on the display 52 (S30).

[0042] When it is determined that the "Start Parking" icon has been touched and that the vehicle 102 is permitted to move by automatic driving (S40), the vehicle 102 is moved by automatic driving along the target trajectory toward the target parking position (S50). When it is determined that the vehicle 102 has reached the target parking position (S130), the fact that the vehicle 102 has reached the target parking position is displayed on the display 52, the shift position of the transmission is shifted to the P range, and the ignition switch is turned off (S140).

[0043] Therefore, the driver can use the overhead image to determine a target parking position and touch the icon 52A to move the vehicle 102 to the target parking position by automatic driving and park the vehicle 102 there.

[0044] <Subroutine for acceleration / deceleration control of automatic driving (Fig. 3)> Next, a subroutine for controlling acceleration and deceleration in the automatic driving in the above-mentioned step 50 will be described with reference to the flowchart shown in Fig. 3. In the automatic driving in step 50, although not shown, the EPS device 42 is automatically controlled in a manner known in the art so that the vehicle 102 moves to the target parking position along the target trajectory, thereby automatically steering the steered wheels.

[0045] In step S60, the CPU calculates the target acceleration / deceleration Gt of the vehicle 102 in a manner known in the art based on the remaining distance from the current position of the vehicle 102 to the turning point Pr or the reference position Pp of the target parking position 110B. Note that the target acceleration / deceleration Gt is a positive value when the target acceleration / deceleration is acceleration, and is a negative value when the target acceleration / deceleration is deceleration.

[0046] In step S70, the CPU calculates an acceleration Gc of the vehicle 102 corresponding to the creep force, based on the creep force Fvc calculated by the drive ECU 20. In this case, if the mass of the vehicle 102 is Mv, the acceleration Gc may be calculated as Fvc / Mv.

[0047] In step S80, the CPU sets a limit change rate Rlim for limiting the rate of change of the vehicle acceleration Gc corresponding to the creep force, according to a subroutine of the flowchart shown in Fig. 4. The limit change rate Rlim is a limit change rate for limiting the rate of change of the vehicle acceleration Gc by limiting the amount of change of the vehicle acceleration Gc per unit time.

[0048] In step S90, the CPU limits the rate of change of the vehicle acceleration Gc corresponding to the creep force calculated in step S70 by the limited rate of change Rlim, thereby calculating the vehicle acceleration Gac corresponding to the creep force after the rate of change limit. Note that the sign-inverted value -Gac of the vehicle acceleration Gac is the additional deceleration after the rate of change limit corresponding to the creep force.

[0049] In step S100, the CPU calculates the larger of the target acceleration / deceleration Gt calculated in step S60 and 0 as a required acceleration Gad, and outputs a signal indicating the required acceleration Gad to the drive ECU 20. Upon receiving the signal indicating the required acceleration Gad, the drive ECU 20 controls the drive device 22 so that the acceleration of the vehicle 102 becomes the required acceleration Gad.

[0050] In step S110, the CPU calculates a revised target acceleration / deceleration Gta as the value obtained by subtracting the vehicle acceleration Gac equivalent to the creep force after the rate of change is limited from the target acceleration / deceleration Gt calculated in step S60, i.e., the sum of the target acceleration / deceleration Gt and the additional deceleration after the rate of change is limited -Gac.

[0051] In step S120, the CPU calculates the smaller of the corrected target acceleration / deceleration Gta calculated in step S110 and 0 as a required deceleration Gbd, and outputs a signal indicating the required deceleration Gbd to the brake ECU 30. Upon receiving the signal indicating the required deceleration Gbd, the brake ECU 30 controls the braking device 32 so that the deceleration of the vehicle 102 becomes the required deceleration Gbd.

[0052] As can be seen from the above description, the target acceleration / deceleration Gt of the vehicle is calculated based on the remaining distance to be traveled by the vehicle 102 (S60), and the acceleration Gc (added deceleration -Gc) of the vehicle 102 corresponding to the creep force Fvc is calculated (S70). A limit change rate Rlim for limiting the rate of change of the added deceleration -Gc is set (S80), and the rate of change of the added deceleration -Gc is limited to the limit change rate Rlim, thereby calculating the added deceleration -Gac after the rate of change limit (S90).

[0053] The larger of the target acceleration / deceleration Gt and 0 is calculated as the required acceleration Gad, and a signal indicating the required acceleration Gad is output to the drive ECU 20 (S100). Furthermore, a corrected target acceleration / deceleration Gta is calculated as the sum of the target acceleration / deceleration Gt and the added deceleration after the rate of change limit -Gac (S110), and the smaller of the corrected target acceleration / deceleration Gta and 0 is calculated as the required deceleration Gbd, and a signal indicating the required deceleration Gbd is output to the brake ECU 30 (S120).

[0054] <Subroutine for setting the limit change rate (Fig. 4)> Next, the subroutine for setting the limit change rate in step 80 described above will be described with reference to the flowchart shown in FIG.

[0055] In step S81, the CPU judges whether or not a large change in acceleration / deceleration of the vehicle 102 is required based on the information about the surroundings of the vehicle acquired by the surrounding information acquisition device 16. If the CPU judges yes, the control proceeds to step S84, and if the CPU judges no, the control proceeds to step S82. A situation in which a large change in acceleration / deceleration of the vehicle is required is, for example, a situation in which the vehicle must pass through a step, a ramp, a ridge, a depression, or the like to reach the target parking position. (B) of FIG. 7 shows a situation in which, after the driving force is increased so that the vehicle 102 climbs over the step 112, the braking force must be rapidly increased so that the vehicle does not collide with an obstacle 114.

[0056] In step S82, the CPU determines whether the acceleration of the vehicle 102 is excessive compared to the remaining distance L to the target stop position 116, and whether a sudden increase in braking force is required. If the CPU determines yes, the control proceeds to step S84, and if the CPU determines no, the control proceeds to step S83. (C) of Fig. 7 illustrates a situation in which the driving force of the vehicle 102 is excessively large even though the remaining distance L to the target stop position 116 is small, and a sudden increase in braking force is required to stop the vehicle at the target stop position.

[0057] In step S83, the CPU determines whether or not the vehicle 102 has passed the target stop position, as shown in (D) of Fig. 7. If the CPU makes a positive determination, the control proceeds to step S84, and if the CPU makes a negative determination, the control proceeds to step S85.

[0058] In step S84, the CPU sets the limit change rate Rlim for limiting the change rate of the vehicle acceleration Gc, which corresponds to the creep force, to a maximum value Rlima (a positive constant).

[0059] In step S85, the CPU determines whether the remaining distance L to the target stop position 116 is less than a reference value Lc (positive constant) as shown in Fig. 7(E). If the CPU makes a positive determination, the control proceeds to step S86, and if the CPU makes a negative determination, that is, if the CPU determines that the remaining distance L to the target stop position 116 is equal to or greater than the reference value Lc as shown in Fig. 7(A), the control proceeds to step S87.

[0060] In step S86, the CPU sets the limit change rate Rlim to the intermediate value Rlimb (a positive constant smaller than the maximum value Rlima). In step S87, the CPU sets the limit change rate Rlim to the minimum value Rlimc (a positive constant smaller than the intermediate value Rlimb).

[0061] As can be seen from the above explanation, in any of the following cases (a) to (c), the limited change rate Rlim for limiting the change rate of the vehicle acceleration Gc corresponding to the creep force is set to the maximum value Rlima (S84). (a) A situation in which a large change in acceleration / deceleration of the vehicle 102 is required (S81) (b) The acceleration of the vehicle 102 is excessive compared to the remaining distance L to the target stop position (S82). (c) The vehicle 102 exceeds the target stopping position (S83)

[0062] When the remaining distance L to the target stop position is less than the reference value Lc (S85), the limited change rate Rlim is set to the intermediate value Rlimb (S86). On the other hand, when the remaining distance L to the target stop position is equal to or greater than the reference value Lc (S85), the limited change rate Rlim is set to the minimum value Rlimc (S87).

[0063] Therefore, in steps S81 to S87, the limit change rate Rlim is variably set based on the information about the surroundings of the vehicle acquired by the surrounding information acquisition device 16, the positional relationship of the vehicle with respect to the target parking position, and the driving conditions of the vehicle so that the limit change rate Rlim increases as the change in the acceleration / deceleration of the vehicle increases.

[0064] <Operation of the embodiment> When the vehicle 102 is being driven automatically to a target parking position, if the vehicle passes over a step or the like, the driving force of the vehicle is temporarily increased, and immediately thereafter the vehicle enters a non-accelerating state, so that the creep force Fvc temporarily increases.

[0065] In a conventional automatic parking device in which the rate of change of the vehicle acceleration Gc corresponding to the creep force is not limited, the additional deceleration temporarily increases in response to a temporary increase in the creep force Fvc, and the required deceleration Gbd temporarily increases. As a result, not only does the vehicle deceleration temporarily increase and the vehicle speed suddenly decrease, but the vehicle speed also fluctuates in an oscillatory manner due to a response delay of the braking device, thereby reducing the ride comfort of the vehicle.

[0066] In contrast, according to the embodiment, the rate of change of the vehicle acceleration Gc corresponding to the creep force is limited by the limited rate of change Rlim, so that a sudden increase in the additional deceleration is suppressed, and therefore a sudden increase in the required deceleration Gbd is suppressed, even when the vehicle passes over a step, etc. Therefore, not only can a sudden decrease in vehicle speed caused by a temporary increase in the deceleration of the vehicle be prevented, but also vibrational fluctuations in the vehicle speed caused by a response delay of the braking device can be prevented, and a decrease in the ride comfort of the vehicle can be prevented.

[0067] For example, assume that the target acceleration / deceleration Gt of the vehicle 102 is −0.1 g, and the vehicle acceleration Gc corresponding to the creep force is 0.05 g, where g is the acceleration of gravity. The required acceleration Gad is 0, and the corrected target acceleration / deceleration Gta is −0.15 g, so the required deceleration Gbd is −0.15 g.

[0068] If the vehicle acceleration Gc corresponding to the creep force suddenly increases to 0.1 g, when the rate of change of the vehicle acceleration Gc corresponding to the creep force is not limited by the limit change rate Rlim, the corrected target acceleration / deceleration Gta is -0.2 g, and the required deceleration Gbd suddenly increases to -0.2 g. In contrast, if the rate of change of the vehicle acceleration Gc corresponding to the creep force is limited by the limit change rate Rlim and the vehicle acceleration Gac corresponding to the creep force after the change rate limit is 0.07 g, the corrected target acceleration / deceleration Gta is -0.17 g, and the required deceleration Gbd becomes -0.17 g, and a sudden increase in the required deceleration Gbd can be suppressed.

[0069] According to the embodiment, the limit change rate Rlim is variably set based on the information on the surroundings of the vehicle, the positional relationship of the vehicle with respect to the target parking position, and the running conditions of the vehicle so that the limit change rate Rlim is increased as the change in the acceleration / deceleration of the vehicle increases (S81 to S87). Thus, the limit change rate Rlim can be variably set according to the conditions when the vehicle is automatically parked. For example, the greater the change in the acceleration / deceleration of the vehicle and the greater the need to stop the vehicle, the greater the limit change rate Rlim can be set, and the vehicle can be effectively decelerated and stopped while suppressing a decrease in the ride comfort of the vehicle. Conversely, the smaller the change in the acceleration / deceleration of the vehicle and the greater the need to ensure the ride comfort of the vehicle, the smaller the limit change rate Rlim can be set to ensure good ride comfort of the vehicle.

[0070] Although the present invention has been described in detail with respect to specific embodiments, the present invention is not limited to the above-described embodiments, and it will be apparent to those skilled in the art that various other embodiments are possible within the scope of the present invention.

[0071] For example, in the above embodiment, the limit change rate Rlim is set to three levels of values ​​in steps S81 to S87. However, the limit change rate Rlim may be set to two levels or four or more levels of values, or may be changed continuously.

[0072] In addition, in the above-described embodiment, the limit change rate Rlim is switched between a maximum value Rlima, an intermediate value Rlimb, and a minimum value Rlimc depending on the situation, but the limit change rate Rlim may be adjusted so as to change smoothly when being switched.

[0073] Furthermore, in the above embodiment, the reference value Lc in the determination in step S85 is a positive constant, but it may be variably set according to the vehicle speed, for example, so that the higher the vehicle speed V, the smaller the reference value Lc. [Explanation of symbols]

[0074] 10...driving assistance ECU, 12...camera sensor, 14...radar sensor, 16...surrounding information acquisition device, 20...driving ECU, 22...driving device, 30...braking ECU, 32...braking device, 40...EPS ECU, 42...EPS device, 50...meter ECU, 52...display, 60...driving operation sensor, 70...vehicle state sensor, 100...automatic parking device, 102...vehicle, 110...parking space, 112...target trajectory

Claims

[Claim 1] an automatic parking device including a surrounding information acquisition device that acquires information about the surroundings of a vehicle; and a control device configured to set a target trajectory of the vehicle to a target parking position based on the information about the surroundings of the vehicle acquired by the surrounding information acquisition device, calculate a target acceleration / deceleration of the vehicle based on a remaining distance to the target parking position along the target trajectory, calculate a required acceleration for a drive device based on the target acceleration / deceleration, and calculate a required deceleration for a brake device based on a sum of the target acceleration / deceleration and an additional deceleration corresponding to a creep force generated immediately after a drive force is temporarily increased by the drive device, the control device is configured to modify the added deceleration by limiting a rate of change of the added deceleration with a limited rate of change, and to calculate a required deceleration based on a sum of the target acceleration / deceleration and the modified added deceleration, Furthermore, the control device is configured to variably set the restriction change rate based on information about the surroundings of the vehicle acquired by the surrounding information acquisition device, the vehicle's positional relationship with respect to the target parking position, and the vehicle's driving conditions, so that the greater the change in the vehicle's acceleration / deceleration, the greater the restriction change rate.

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