Patent Publication Number: US-2021179174-A1

Title: Parking assist system and vehicle with automated parking capability

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application claims the benefit of priority to Japanese Patent Application No. 2019-225952 filed on 13 Dec. 2019, the disclosures of all of which are hereby incorporated by reference in their entireties. 
     TECHNICAL FIELD 
     The present invention relates to a parking assist system and a vehicle with automated parking capability. 
     BACKGROUND OF THE INVENTION 
     Japanese Patent Application Publication No. 2008-094117 (hereinafter, referred to as Patent Document 1) discloses a vehicular braking force control device capable of reducing a steering force required for stationary steering, while suitably holding a vehicle suspended. 
     Japanese Patent No. 5834058 (hereinafter, referred to as Patent Document 2) discloses a parking assist ECU to execute parking assist control capable of recognizing environment of a vehicle by a camera and then guiding the vehicle to a desired parking position. 
     SUMMARY OF THE INVENTION 
     Problems to be Solved 
     However, the vehicular braking force control device of Patent Document 1 is made to reduce a steering force in braking force reduction control, and accordingly has not taken noisemaking in consideration when a vehicle is braked (brake noise). That is, a brake pad is pressed against a disk by oil pressure, when a vehicle is braked. At this time, a brake noise may be made, depending on balance between a frictional force generated by the brake pad and a driving force. A brake noise is made when the brake pad is separated off the disk after being pressed against the disk. This brake noise brings uncomfortable feeling or discomfort to a driver. 
     Particularly in automated steering with parking assist control of Patent Document 2, a brake noise may be made at stationary steering (steering with a vehicle in a suspended condition) after the vehicle is suspended (while brakes being on hold) at a predetermined position. In this case, a driver may sense a brake noise sensitively more than normal because automated steering is being executed. All the more in a case where the vehicle is an EV (Electric Vehicle), which is superior in quietness, or the like, a brake noise at stationary steering notably brings uncomfortable feeling or discomfort to a driver. 
     The present invention has been made in view of above-identified problems and is intended to provide a parking assist system and a vehicle with automated parking capability to prevent a brake noise at stationary steering, while brakes being on hold, in automated steering by the parking assist system. 
     Solution to Problem 
     A parking assist system of the present invention is capable of solving the above-identified problems, and includes: an environment recognizer to recognize environment of a vehicle; a behavior controller to execute behavior control inclusive of steering and acceleration/deceleration, based on recognized information; a suspension hold controller to suspend the vehicle with the behavior control and hold the vehicle suspended until receiving behavior-related operation by a driver; an automated-parking controller to set a reverse steering position, based on a current position of the vehicle and a desired parking position decided by the driver, between the current position and the desired parking position, move from the current position to the reverse steering position, and execute stationary steering at the reverse steering position; and a brake fluid pressure controller to increase a braking force of the vehicle when stationary steering is executed at the reverse steering position. 
     Advantageous Effects of the Invention 
     According to the present invention, a brake noise at stationary steering, while brake hold being in operation, is prevented in automated steering with parking assist control. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG. 1  is a block diagram of a system configuration, centered around an automated-parking control unit according to an embodiment of the present invention; 
         FIG. 2  is a top view of a vehicle mounted with the automated-parking control unit according to the embodiment of the present invention, to show mounting positions of cameras and sonars; 
         FIG. 3  shows a disk brake of the vehicle mounted with the automated-parking control unit according to the embodiment of the present invention: 
         FIG. 4A  is a top view of a parking area, to show the vehicle, mounted with the automated-parking control unit according to the embodiment of the present invention, in search of a space for parking; 
         FIG. 4B  is a top view of the parking area, to show the vehicle, mounted with the automated-parking control unit according to the embodiment of the present invention, in search of a space for parking; 
         FIG. 4C  is a top view of the parking area, to show the vehicle, mounted with the automated-parking control unit according to the embodiment of the present invention, in search of a space for parking; 
         FIG. 5  shows a flowchart of a process executed by the automated-parking control unit according to the embodiment of the present invention; 
         FIG. 6  shows a flowchart of a process executed by the automated-parking control unit according to the embodiment of the present invention; 
         FIG. 7  is a top view of the parking area, to illustrate processing executed by the automated-parking control unit according to the embodiment of the present invention; 
         FIG. 8  is a top view of the parking area, to illustrate processing executed by the automated-parking control unit according to the embodiment of the present invention; 
         FIG. 9  is a top view of the parking area, to illustrate processing executed by the automated-parking control unit according to the embodiment of the present invention; 
         FIG. 10  is a top view of the parking area, to illustrate processing executed by the automated-parking control unit according to the embodiment of the present invention; 
         FIG. 11  is a plan view of a selection screen displayed on a touch panel through processing by the automated-parking control unit according to the embodiment of the present invention; 
         FIG. 12  is a flowchart of brake fluid pressure control, at stationary steering, by a brake fluid pressure controller of the automated-parking control unit according to the embodiment of the present invention; and 
         FIG. 13  is a top view of the parking area, to illustrate the brake fluid pressure control, at stationary steering, by the brake fluid pressure controller of the automated-parking control unit according to the embodiment of the present invention. 
     
    
    
     EMBODIMENTS OF THE INVENTION 
     Hereinafter, an embodiment of the present invention is described with reference to drawings. Directions of front, rear, right, and left are indicated in the drawings by arrows.  FIG. 1  is a block diagram of a system configuration of the present embodiment, centered around an automated-parking control unit  1 .  FIG. 2  is a top view of a vehicle  100  mounted with the system in  FIG. 1 . 
     The automated-parking control unit  1  is an automated-parking ECU (Electronic Control Unit) to implement a parking assist system of the present invention. The automated-parking control unit  1  is configured to be centered around a microcomputer to implement functions of various controllers as follows, through processing executed by control programs of the controllers. That is, the automated-parking control unit  1  executes functions of a behavior controller  1   b  and an automated-parking controller  11  (a suspension hold controller). The automated-parking controller  11  executes functions of an available parking position detector  11   a  and a desired parking position detector  11   b.  In addition, the automated-parking control unit  1  executes functions of a parking activation instruction detector  12 , a brake hold instructor  13 , and a brake hold continuation determiner  14 . Further, the automated-parking control unit  1  executes functions of a brake hold cancel instructor  15 , a first parking operation interrupter  16 , a second parking operation interrupter  17 , a resume instructor  18 , and a brake fluid pressure controller  19 . Details of processing executed by these components are described below. 
     The automated-parking control unit  1  has a camera group  21  and a sonar group  22  connected thereto. Note that the components connected to the automated-parking control unit  1  (connection is indicated by mapping lines) may be connected to the automated-parking control unit  1 , either directly or via CAN (Controller Area Network). 
     The camera group  21  includes cameras mounted on the vehicle  100  in  FIG. 2 . That is, the vehicle  100  is provided with a front camera  21 F arranged at a front of the vehicle  100  to image objects in front of the vehicle  100 . Likewise, the vehicle  100  is provided with a rear camera  21 R arranged at a rear of the vehicle  100  to image objects posterior to the vehicle  100 . Additionally, the vehicle  100  is provided with a side camera  21 RF arranged at a right front of the vehicle  100  to image objects on the right side of the vehicle  100 . Likewise, the vehicle  100  is provided with a side camera  21 LF arranged at a left front of the vehicle  100  to image objects on the left side of the vehicle  100 . Note that the side cameras  21 RF and  21 LF may be desirably arranged at front ends of door mirrors or off from the door mirrors to avoid the door mirrors from being imaged excessively large. Of course, the side cameras may be arranged at other positions away from the door mirrors to some extent. 
     The sonar group  22  includes sonars mounted on the vehicle  100  in  FIG. 2 . That is, the vehicle  100  is provided with four front sonars  22 F aligned at the front of the vehicle  100  substantially at equal intervals. The four front sonars  22 F detect obstacles in front of the vehicle  100 . In addition, the vehicle  100  is provided with four rear sonars  22 R aligned at the rear of the vehicle  100  substantially at equal intervals. The four rear sonars  22 R detect obstacles posterior to the vehicle  100 . The front sonars  22 F and rear sonars  22 R detect obstacles in moving directions, forward and rearward, respectively. 
     The vehicle  100  is further provided with a side sonar  22 RF at a right-front lateral side of the vehicle  100 . The side sonar  22 RF detects obstacles in a field between a right-front direction and a right lateral direction from the vehicle  100 . Likewise, the vehicle  100  is provided with a side sonar  22 LF at a left-front lateral side of the vehicle  100 . The side sonar  22 RF detects obstacles in a field between a left-front direction and a left lateral direction from the vehicle  100 . Additionally, the vehicle  100  is provided with a side sonar  22 RR at a right-rear lateral side of the vehicle  100 . The side sonar  22 RR detects obstacles in a field between a right-rear direction and a right lateral direction from the vehicle  100 . Likewise, the vehicle  100  is provided with a side sonar  22 LR at a left-rear lateral side of the vehicle  100 . The side sonar  22 LR detects obstacles in a field between a left-rear direction and a left lateral direction from the vehicle  100 . The side sonars  22 RF,  22 LF,  22 RR,  22 LR detect obstacles which may possibly be hit by the vehicle  100 . Dashed lines in  FIG. 2  each indicate a spatial range where the corresponding sonar can detect obstacles. Note that the number, and installation positions, of cameras and sonars as described above are not limited to those described, and the cameras and/or sonars may be increased or decreased in number, and/or installed at different positions. However, the number, and installation positions, of cameras and sonars are desirably selected as much as possible so as to detect conditions all around the vehicle  100 . Alternatively, sensors other than the cameras and sonars may be used to detect conditions external to the vehicle  100 . 
     Back to  FIG. 1 , the automated-parking control unit  1  has an inertia sensor  23 , wheel speed sensors  24 , a shift position sensor  25 , and a gradient sensor  26  (road surface gradient detector) connected thereto. The inertial sensor  23  detects acceleration of the vehicle  100 . The wheel speed sensors  24  detect wheel speeds of wheels of the vehicle  100 . The shift position sensor  25  detects a shift position of a transmitter mounted on the vehicle  100 . The gradient sensor  26  detects a gradient of a road surface as a gradient of a road surface on which the vehicle is located. The gradient sensor  26  has a gyroscope and uses an angular speed detected by the gyroscope to calculate an angle in a vertical direction between a pitch direction and a horizontal surface, so as to be detected as a gradient of a road surface. The sensors  21  to  25  of a sensor group are all configured to communicate with the automated-parking control unit  1  via a vehicle network. 
     In addition, the automated-parking control unit  1  has an information input/output device  31  connected thereto. The information input/output device  31  includes a touch panel  32  and a speaker  33 . A main body of the information input/output device is arranged in the vicinity of a driver seat so that a driver can operate the touch panel  32  and the like. The information input/output device  31  displays various information on the touch panel  32 , outputs various kinds of sound from the speaker  33 , and receives various kinds of operation through the touch panel  32 . 
     In other words, the information input/output device  31  can display automotive navigation information, produced based on a satellite positioning system or the like, and outputs sound from the speaker  33 . The information may include information received from a vehicle information and communication system (VICS). 
     The information input/output device  31  may also receive television broadcasting and/or sound broadcasting to display images on the touch panel  32  and output sound from the speaker  33 . The information input/output device  31  may also include an optical disk device (not shown) to play a CD (Compact Disk), a DVD (Digital Video or Versatile Disk), a BD (Blu-ray Disc), or the like. The information input/output device  31  may also include an HDD (Hard Disk Drive), not shown, to play sound such as music stored therein. The information input/output device  31  may further inform various messages from the vehicle  100  or equipment mounted thereon, such as an ETC (Electronic Toll Collection system), and receive various kinds of operation on the touch panel  32  from the vehicle  100  and/or equipment mounted thereon. 
     The automated-parking control unit  1  has a braking system  41  connected thereto. The braking system  41  is a system to brake the vehicle  100 . The braking system  41  includes a braking device  42  to brake the vehicle  100 , and a braking control unit  43  to control the braking device  42 . The braking control unit  43  includes a function as an automated brake hold control unit  44 . The automated brake hold control unit  44  works as an automated brake hold controller. The braking device  42  generates fluid pressure (oil pressure) and supplies the fluid pressure to wheel cylinders of wheels, not shown, to produce frictional braking forces. Note that the braking system  41  may utilize regenerative brakes in combination in a case where the vehicle  100  is a hybrid vehicle or the like. The braking device  42  is a device applied with a brake-by-wire system, for example. Accordingly, the braking device  42  is capable of generating a braking force, regardless of operation on a brake pedal (not shown). Alternatively, the braking device  42  may be a system mounted with an electric brake booster. Even in this case, the braking device  42  is capable of generating a braking force, regardless of operation on a brake pedal (not shown). The braking control unit  43  is a control device to control the braking device  42 . 
     The automated brake hold control unit  44  is a feature included in the braking control unit  43 , to control an automated brake hold function to hold a braking state even when a driver has stepped on a brake pedal (not shown) and then has stepped off the brake pedal. Note that the automated brake hold function cancels an automated brake hold state when a predetermined condition is satisfied, such as operation on an acceleration pedal (not shown). The automated brake hold state is activated or canceled through operation of a brake hold switch  45  arranged in the vicinity of a driver seat within the vehicle  100 . 
     The automated-parking control unit  1  has a driving system  51  connected thereto. The driving system  51  is a system to cause the vehicle  100  to travel. The vehicle  100  is a hybrid vehicle in the present example and includes an engine  52  and a motor/generator  53  as driving sources. A hybrid control unit  54  controls the engine  52  and the motor/generator  53  to cause the vehicle  100  to travel. Note that the vehicle  100  is not limited to a hybrid vehicle. Only the engine  52  is used as a driving source for a gasoline vehicle. Only a motor is used as a driving source for an electric vehicle inclusive of a fuel cell vehicle. 
     A transmission system  61  is a system to shift gears of the vehicle  100 . The transmission system  61  includes a transmission  62  to shift gears of the vehicle  100 , a transmission control unit  63  to control the transmission  62 , and a shift lever  64  connected with the transmission  62 . The transmission  62  may be an automatic transmission or a manual transmission. The transmission system is capable of shifting gears by the transmission  62 , without operation by a driver, through control by the transmission control unit  63 . In this case, the transmission control unit  63  changes a position of the shift lever  64 , depending on the shifting. The automated-parking control unit  1  has a driver presence determination unit  65  connected thereto. The driver presence determination unit  65  determines whether or not a driver is seated in a driver seat. 
     The automated-parking control unit  1  has an EPS (Electric Power-Steering) system  71  connected thereto. The EPS system  71  is a system to assist steering by a driver. The EPS system  71  includes a steering shaft  73  mounted with a steering wheel  72 , a driving motor  74  to rotationally drive the steering shaft  73 , and an EPS control unit  75  to control the driving motor  74 . The EPS system  71  causes the steering shaft  73  to be rotated by the driving motor  74  as a driving source, to assist the driver turning the steering wheel  72  for steering. 
     The automated-parking control unit  1  includes an environment recognizer  1   a  to recognize environment of a vehicle, and a behavior controller  1   b  to execute behavior control inclusive of steering and acceleration/deceleration, based on recognized information, as shown in  FIG. 1 . The environment recognizer la recognizes conditions such as positions of surrounding vehicles, speed, and acceleration, based on information inputted from the camera group  21 , the sonar group  22 , and the like. The surrounding vehicles are vehicles traveling around the vehicle in question and heading in the same direction as the vehicle in question. The environment recognizer  1   a  may also recognize positions of other objects, such as a guard rail, a utility pole, a parked vehicle, and a pedestrian, in addition to the surrounding vehicles. 
     The behavior controller  1   b  suspends the vehicle  100  with behavior control, and holds the suspension until receiving behavior-related operation by the driver. 
     The automated-parking controller  11  (suspension hold controller) suspends the vehicle with behavior control by the behavior controller  1   b,  and holds the suspension until receiving behavior-related operation by the driver. 
     Based on a current position of the vehicle  100  and a desired parking position decided by the driver, the automated-parking controller  11  sets a reverse steering position  222  (see  FIGS. 10 and 13 ) between the current position and the desired parking position, moves from the current position to the reverse steering position  222 , and executes stationary steering at the reverse steering position  222 . 
     The brake fluid pressure controller  19  increases a braking force of the vehicle  100  (e.g., increases a brake fluid pressure) when stationary steering is executed at the reverse steering position  222 , while automated-parking control is executed by the automated-parking controller  11 . The brake fluid pressure is desired to be such a high brake fluid pressure that wheels are inhibited from being rotated by reaction forces from the road surface caused by the stationary steering. 
     The brake fluid pressure controller  19  executes brake fluid pressure control to increase a brake fluid pressure from a predetermined pressure to a desired brake fluid pressure, and the desired brake fluid pressure is varied depending on a steering speed and/or a steering angle at the stationary steering. 
     The brake fluid pressure controller  19  varies a brake fluid pressure based on a gradient of a course of movement. When the gradient is of a downhill, for example, the brake fluid pressure controller  19  increases a brake fluid pressure, as compared with a case where the gradient is of a fiat ground. 
     The brake fluid pressure controller  19  executes brake fluid pressure control to increase a brake fluid pressure from the predetermined pressure to the desired brake fluid pressure, where the desired brake fluid pressure is set to one with a brand-new brake pad as standards. 
     The automated-parking controller  11  shifts a position in a shift range of the transmission mounted on the vehicle  100  from a D-range to an R-range at the reverse steering position  222 , based on shift position data from the shift position sensor  25 . 
     When braking operation is canceled by the driver, the automated-parking controller  11  starts moving to the desired parking position. 
     The vehicle  100  is provided with the gradient sensor  26  to detect a gradient of a road surface on which the vehicle  100  is located, and the brake fluid pressure controller  19  varies a brake fluid pressure, based on a gradient of a course of movement detected by the gradient sensor  26 . Here, when the gradient is of a downhill, the brake fluid pressure controller  19  increases the brake fluid pressure, as compared with a case where the gradient is of a flat ground. 
     The vehicle  100  (see  FIG. 1 ) is provided with a disk brake  300  to press brake pads  311 ,  312  (see  FIG. 3 ) against a disk  320  by way of oil pressure to brake the vehicle  100 . The brake fluid pressure controller  19  executes brake fluid pressure control to increase a brake fluid pressure from a constant pressure (predetermined pressure) to the desired brake fluid pressure. The desired brake fluid pressure may be set to one with a brand-new brake pad as standards. 
       FIG. 3  shows the disk brake  300  for the vehicle  100 . As shown in  FIG. 3 , the disk brake  300  stops the disk  320  in a disk shape from being rotated together with a wheel, not shown, to brake the vehicle. Hereinbelow, an orientation of a central axis of the disk  320  is referred to as an orientation of a rotation axis O. The disk brake  300  includes: a caliper  310  slidable in a parallel direction parallel to the rotation axis of the wheel with reference to a vehicle body, between an initial position and an operational position; a first brake pad  311  facing one surface of the disk  320  to be rotated together with the wheel; a second brake pad  312  facing the other surface of the disk  320  and supported by the caliper  310  via a bridge  317  so as to be relatively movable in the parallel direction; and an oil pressure cylinder  313  supported by the caliper  310  and supporting the first brake pad  311 , and moving the caliper  310 , which has been positioned at the initial position by a reaction force received from the disk  320  via the first brake pad  311  when a driving force has been generated to move the first brake pad  311  so as to contact the disk  320 , to the operational position to cause the second brake pad  312  to contact the disk  320 . 
     The first brake pad  311  is an inner friction pad disposed on an inner side, inner in a vehicle width direction than the disk  320 . The second brake pad  312  is an outer friction pad disposed on an outer side, outer in the vehicle width direction than the disk  320 . 
     The oil pressure cylinder  313  is positioned on an interior side of the vehicle with respect to the disk  320 . The oil pressure cylinder  313  specifically includes a cylinder  313  fixed to the caliper  310  and having an axis line in parallel to the rotation axis O, and a piston  314  partially positioned within the cylinder  313  and slidable with respect to the cylinder  313 . The piston  314  supports the first brake pad  311  at a front end thereof. The cylinder  313  is formed therein with a communication hole  316  to communicate a fluid pressure chamber  315  with outside, and brake fluid is introduced into the fluid pressure chamber  315  through the communication hole  316 . The brake fluid introduced into the fluid pressure chamber  315  causes the piston  314  to proceed toward the disk  320 . 
     When a driver of the vehicle steps on the brake pedal, oil pressure increases in the oil pressure cylinder  313  to move the piston  314  of the oil pressure cylinder  313  toward the disk  320  so that the first brake pad  311  is pressed against a side surface on the interior side of the disk  320 . 
     The disk  320  is unable to be moved in the rotation axis direction, relative to the vehicle body. Accordingly, when the first brake pad  311  is pressed against the disk  320 , the first brake pad  311  receives a reaction force from the disk  320 , to cause the caliper  310  at the initial position to be relatively slid, with respect to the vehicle body, toward the interior side so as to be moved to the operational position. Then, the second brake pad  312  supported by the caliper  310  is pressed against a side surface on an exterior side of the disk  320 . As a result, a braking force (friction resistance force) is exerted to the disk  320  from the second brake pad  312  and the first brake pad  311 , to decrease a rotation speed of the disk  320 . 
     On the contrary, when the driver steps off the brake pedal, the oil pressure in the oil pressure cylinder  313  is reduced to cause the piston  314  to return to the initial position. That is, the oil pressure cylinder  313  comes close to the disk  320 , and the caliper  310  at the operational position is moved to the initial position. Accordingly, the second brake pad  312  is separated from the disk  320 , and the first brake pad  311  is separated from the disk  320  toward the interior side, with the piston  314  moving to the initial position. 
     &lt;Brake Noise&gt; 
     When the vehicle  100  is braked, the brake pads  311 ,  312  are pressed by oil pressure against the disk  320 . At this time, the caliper  310  may be vibrated, depending on such as conditions of the brake pads  311 ,  312  and a condition of the disk  320 , to make an abnormal noise, that is, a brake noise. When braking is gradually canceled, for example, an abnormal noise (brake noise) may be made, depending on a balance between a frictional force generated by the brake pads  311 ,  312  and a driving force. As shown in  FIG. 3 , such a noise can be made when the brake pads  311 ,  312  are separated from the disk  320  after being pressed against the disk  320 . 
     In a case of a manual-mode driving where a driver can adjust a canceling speed of braking with a stepping force on the brake pedal, an experienced driver can reduce an abnormal noise by adjusting a stepping force. However, in a case where braking is automatically canceled, an abnormal noise is desirably prevented by control of the vehicle itself. 
     Especially, when a stationary steering (steering with a vehicle in a suspended condition) is operated with automated steering by the parking assist system after the vehicle has been suspended (with the brake on hold) at a predetermined position, if a brake noise is made, the driver is more sensitive to the brake noise for a reason of automated steering. All the more in a case where the vehicle is an EV (Electric Vehicle), which is superior in quietness, or the like, a brake noise at stationary steering notably brings uncomfortable feeling or discomfort to a driver. 
     In the present embodiment, when a stationary steering is executed at the reverse steering position  222 , at the time of automated-parking control by the automated-parking controller  11 , a brake fluid pressure of the vehicle  100  is increased to press the brake pads  311 ,  312  against the disk 320  more strongly to inhibit the disk  320  from being rotated by a reaction force from the road surface at stationary steering, so that the brake pads  311 ,  312  are prevented from making brake noises. 
     &lt;Automated-Parking Operation&gt; 
     Hereinbelow, a description is given of operation of systems centered around the automated-parking control unit  1 . “Automated-parking operation” hereinbelow refers to a series of operation in a flowchart in  FIGS. 5 and 6 , to be described below, in which the automated-parking control unit  1  controls the systems, for automated driving, to drive the vehicle  100  to execute automated-parking. “Automated-parking function” refers to all the processing of automated-parking in the flowchart in  FIGS. 5 and 6 , inclusive of the “automated-parking operation” to be executed mainly by the automated-parking control unit  1 . The automated-parking control unit  1  controls automated-parking. For this purpose, the camera group  21  and the sonar group  22  are used to detect a space for parking in a parking area or the like.  FIGS. 4A to 4C  each show the vehicle  100 , in a top view, in search of a space for parking. 
     At first,  FIG. 4A  shows the vehicle  100 , in a top view, in search of a space for parking in a parking area  200 , mainly using the front camera  21 F of the camera group  21 . After the vehicle  100  entering the parking area  200 , parking slots  202  segmented by white lines  201  are in a row respectively on the right and left sides as viewed from the vehicle  100 , where some parking slots  202  have other vehicles  203  already parking and other parking slots  202  are available for parking. The vehicle  100  is driven by the driver to slowly move forward in a direction indicated by an arrow  208 . 
     Images taken by the front camera  21 F (see  FIG. 2 ) allow for recognizing an area  211  as an available space for the vehicle  100  to park. The images taken by the front camera  21 F are processed with predetermined image processing to allow for recognizing luminance differences. This allows the vehicle  100  to recognize the area  211  available for parking. Recognition by camera is good at recognizing, the white lines  201 . Recognition by camera includes space recognition capability. Recognition by camera is not good at recognizing snow, white walls, and other nearby vehicles. Accordingly, only the images taken by the front camera  21 F are not enough to control braking for obstacles, which is required for automated-parking. 
     Then, the sonar group  22  is used in combination.  FIG. 4B  is a top view of the parking area, to show the vehicle  100  in search of a space for parking in the parking area  200 , using all sonars of the sonar group  22 . A sonar can detect obstacles by transmitting and receiving sonic waves, and is good at detecting nearby obstacles, which a camera is not good at. Sonars are therefore required to accurately control braking for obstacles. Additionally, a sonar has a higher space recognition capability than a camera, so that the sonar group  22  is helpful to conduct various ways of parking.  FIG. 4B  shows an area  221  available for parking, recognized by the sonar group  22 . 
       FIG. 4C  is a top view of the parking area, with the area  211  and the area  221  collectively shown. The front camera  21 F and the sonar group  22  are used in combination to recognize a wide space as being available for parking. This also eases controlling braking for obstacles. In the example in  FIG. 4C , a parking slot  202   a  is determined to be a space for automated-parking. Additionally, a space on the far right, as viewed from the vehicle  100 , is empty and thus determined as a position to start reverse steering of the vehicle  100 . This allows the automated-parking control to move the vehicle  100  forward and turn the steering wheel to the right, suspend the vehicle  100  at the reverse steering position  222  (arrow  223 ), and reversely turn the steering wheel and move the vehicle  100  backward into the parking slot  202   a  (arrow  224 ). 
     Hereinabove is a summary of automated-parking to use the front camera  21 F and the sonar group  22  in combination, and a automated-parking process is described below in, detail.  FIGS. 5 and 6  each show a flowchart of a process executed by the automated-parking control unit  1 .  FIGS. 7 to 10  are each a top view of the parking area, to illustrate processing executed by the automated-parking control unit  1 . Note that the flowchart shows a summary of a series of processing to be described below, but does not show detailed processing executed by the automated-parking control unit  1 . Processing not shown in the flowchart is described below as required. 
     First, the driver personally drives the vehicle  100  to enter the parking area  200 , as indicated by the arrow  208 . At this time, the driver operates the touch panel  32  or the like to instruct activating an automated-parking function (Yes in S 1 ). The instruction of activating the automated-parking function is received by the parking activation instruction detector  12 . Then, the parking activation instruction detector  12  displays a predetermined automated-parking function screen on the touch panel  32  (S 2 ). Note that various kinds of automated-parking function screens are displayed, as required, in the series of processing. The available parking position detector  11   a  of the automated-parking controller  11  uses the front camera  21 F and the sonar group  22  in combination, in a manner as described above with reference to  FIGS. 4A to 4C . The available parking position detector  11   a  then searches for an available parking slot for parking, through the combined usage (S 3 ). 
     Following processing is executed in S 3  based on the searching result. First, the available parking position detector  11   a  detects available parking positions (the parking slots  202 ) for the vehicle  100 . Parking slots  202   a,    202   b  are candidates for desired parking positions in the example in  FIG. 8 . Additionally, the available parking position detector  11   a  calculates a route to avoid obstacles when the vehicle  100  parks in the parking slot  202   a  or  202   b,  based on the detection results by the front camera  21 F and the sonar group  22 . 
     Next, the desired parking position detector  11   b  estimates a current position of the vehicle  100 , based on the detection results by the inertia sensor  23  and the wheel speed sensors  24 . The desired parking position detector  11   b  then calculates a desired moving route of the vehicle  100  for parking in the parking slot  202   a  or  202   b,  based on the current position. The desired parking position detector  11   b  then displays positional relationships between the vehicle  100  (vehicle in question) and the parking slots  202   a,    202   b  on the touch panel  32 . The parking slots  202   a,    202   b  are each indicated by a marking in the image, such as enclosing the slot with a frame  205 , for easy understanding of the driver. 
     When the result has been “Yes” in S 1 , processing in  53  is executed (also when the result is No in S 4 ), while the driver personally drives the vehicle  100  to move within the parking area  200 . Then, when the driver steps on the brake pedal (not shown) (Yes in S 4 ) to stop the vehicle  100 , the desired parking position detector  11   b  executes the next processing. That is, with the driver operating the touch panel  32  to select a desired parking position (Yes in S 5 ), the desired parking position detector  11   b  determines the selected position as the desired parking position. The selection may be made such as by touching an area indicated by the frame  205 . When the selection has not been made (No in S 5 ), the processing in S 3  is continued. Note that the sequence of processing in S 4  and S 5  may be reversed. When the desired parking position is determined as described above (Yes in S 5 ), the desired parking position detector  11   b  displays a marking  231 , as in  FIG. 9 , within the image of the desired parking position (parking slot  202   a  in this case) on the touch panel  32 . 
     Next, the brake hold instructor  13  instructs the automated brake hold control unit  44  to turn on an automated brake hold function (S 6 ). The automated brake hold control unit  44  works as the automated brake hold controller. This allows for automatically retaining a state of the vehicle  100  being braked, even when the driver steps off the brake pedal (not shown). 
     The first parking operation interrupter  16  subsequently starts counting all elapsed time (first elapsed time) with a timer (S 7 ). The automated-parking controller  11  displays an automated-parking message on the touch panel  32 , and informs the driver of the automated-parking message by way of the speaker  33  (S 8 ). In this case, the automated-parking message may only be displayed on the touch panel  32 . Here, the message for the driver is given to the driver using an HMI (Human Machine Interface) internal notification message such as “please step off the brake pedal.” The message can be one to the effect “Automated brake hold has been turned on. In order to make automated-parking start, please push the brake hold switch, hands off the steering wheel, and step off the brake pedal,” for example. 
     Once the driver has executed all the actions instructed in the message, the brake hold switch  45  is pushed down to cancel the brake hold switch  45  (Yes in S 9 ). In this case, pushing down the brake hold switch  45  can be interpreted as operation by a cancel instruction controller. When the brake hold switch  45  is not canceled (No in S 9 ), the message described above is continuously displayed on the touch panel  32 . Note that when predetermined operation is made in course of a series of processing (S 2  to S 8 ) as described above, the series of automated-parking processing is discontinued. The operation includes the driver operating the touch panel  32 , on a screen of the automated-parking function displayed thereon, to discontinue operation of the automated-parking function and intentionally operating the shift lever  64 . 
     When the brake hold switch  45  is canceled (Yes in S 9 ), processing in S 10  is executed. That is, the brake hold cancel instructor  15  instructs the automated brake hold control unit  44  to turn off the automated brake hold function (S 10 ). This leads to canceling the vehicle  100  being braked. In addition, the brake hold continuation determiner  14  stores such a history that the automated brake hold function has been operated in S 6  into a non-volatile memory or the like (S 10 ). Further, the automated-parking controller  11  starts automated-parking operation (operation details are described below) (S 10 ). Furthermore, the second parking operation interrupter  17  starts counting elapsed time (second elapsed time) with the timer (S 10 ). Note that when there is no operation on the brake pedal (not shown), the automated-parking controller  11  executes following control. That is, the automated-parking controller  11  cancels the brake hold switch  45  (S 9 ), but does not proceed to automated-parking operation (S 10 ). However, even in this case, the automated brake hold function itself is kept ON (S 6 ). 
     The automated-parking operation started by the automated-parking controller  11  is as follows. That is, the automated-parking controller  11  control the vehicle  100  so as to move on the desired moving route as determined in S 3 , as shown in  FIG. 10 . The automated-parking controller  11  controls the braking system  41 , the driving system  51 , the transmission system  61 , and the EPS system  71 . This causes the vehicle  100  to move backward to the parking slot  202   a  as the desired parking position. 
     That is, the automated-parking controller  11  controls these systems so that the vehicle  100  moves forward with the D-range as indicated by the arrow  223 , and suspends at the reverse steering position  222 . Next, the automated-parking controller  11  causes the vehicle  100  to move backward with the R-range into the parking slot  202   a  as the desired parking position, and then to stop. 
     In step S 100 , the brake fluid pressure controller  19  (see  FIG. 1 ) executes brake fluid pressure control to increase the brake fluid pressure, while holding the vehicle  100  suspended, at the time of stationary steering (see  FIG. 12  to be described below). 
     After the automated-parking operation has been started (S 10 ), a determination is made whether or not there is any interruption condition to interrupt the automated-parking function while the automated-parking is in operation (S 11 ). Namely, the interruption condition in S 11  includes the steering wheel  72  being operated and the shift lever  64  being shifted to an N-range. 
     In addition, the first parking operation interrupter  16  determines in S 11  whether or not the first elapsed time (the counting has been started in S 7 ) is equal to or greater than a predetermined time. The first elapsed time is a time since the desired parking position has been decided (S 5 , S 7 ) until operation of canceling the automated brake hold by way of the brake hold switch  45  is received (Yes in S 9 ). The first elapsed time being equal to or greater than a predetermined time is also an interruption condition. Further, the second parking operation interrupter  17  determines in S 11  whether or not the second elapsed time (the counting has been started in S 10 ) is equal to or greater than a predetermined time. The second elapsed time is a time since the brake hold switch  45  has been operated (Yes in S 9 ) until canceling operation on the brake pedal (not shown) is detected (Yes in S 9 ). The second elapsed time being equal to or greater than a predetermined time is also an interruption condition. 
     The determination, by the driver presence determination unit  65 , of a driver not being seated in a driver seat is also an interruption condition. The driver presence determination unit  65  is implemented with a seating sensor to detect whether or not the driver is seated in the driver seat, an in-vehicle camera to image interior of the vehicle (image processing allows for determining whether or not the driver is seated in the driver seat), a door opening sensor to detect whether or not a door for the driver seat is opened, or the like. Additionally, an interruption condition can be selected from various conditions to be considered to interrupt an automated-parking function. When the automated-parking operation has been completed without any interruption condition (Yes in S 12 ), the touch panel  32 , the speaker  33 , and/or the like is/are used to inform that the automated-parking operation has been completed. Then, the processing proceeds to S 13 . When the automated-parking operation has been interrupted with some interruption condition (No in S 12 ), the processing proceeds to S 16 . 
     In S 13 , the brake hold continuation determiner  14  determines whether a history of automated brake hold operation has been stored in S 10 . When such a history is stored (Yes in S 13 ), the braking system  41  is controlled in S 14  to turn on the automated brake hold function again, and the processing proceeds to S 15 . The vehicle  100  is thus braked to stop, although the driver does not step on the brake pedal (not shown). When such a history is not stored (No in S 13 ), the processing proceeds to S 15 . In this case, the automated brake hold function is kept off. Following is the case where a history of automated brake hold operation has not been stored in S 10 . That is, even when the automated brake hold function is turned on in S 6 , the driver deliberately operates the brake hold switch  45  to turn off the function. In S 15 , the automated-parking controller  11  controls the shift lever  64  to be shifted to the P-range, and then the automated-parking ends. 
     In S 16 , some interruption condition exists (Yes in S 11 ) and therefore the automated-parking function is interrupted. Then, a determination is made whether or not there is any condition for resuming the automated-parking function (S 17 ). Such a resume condition includes a predetermined condition being fulfilled. The predetermined condition includes predetermined operation having been executed on a selection screen  81 , shown in  FIG. 11 , as one of screens displayed on the touch panel  32  for the automated-parking function. The selection screen  81  shows a resume switch  82  and a cancel switch  83 . The driver operating the resume switch  82  becomes a resume condition. When the cancel switch  83  is operated, canceling the automated-parking function is selected. 
     When there is a resume condition (Yes in S 17 ), the processing returns to S 2  and the automated-parking function is resumed. When there is no resume condition and a predetermined time has elapsed (No in S 17 , Yes in S 18 ), canceling the automated-parking function is settled (S 19 ), and a series of processing ends. When there is no resume condition and the predetermined time has not elapsed (No in S 17 , No in S 18 ), the processing returns to S 16 . Note that when the cancel switch  83  is operated, the automated-parking function may be canceled without waiting for the predetermined time to elapse (Yes in S 18 ). 
     Note that when there is some interruption condition (Yes in S 11 ), fulfilling the resume condition (Yes in S 17 ) allows for resuming the automated-parking function from S 2 . In contrast, when the cancel condition is fulfilled during a series of operation of automated-parking function, the processing itself in  FIGS. 5 and 6  is canceled to have no resuming. When the processing needs to be resumed, the processing from SI is newly executed. The cancel condition includes the shift lever  64  being shifted to the P-range, electric parking brake being operated, and the touch panel  32  or the like being operated to instruct activating the automated-parking function, during a series of operation of the automated-parking function. In addition, a series of operation of the automated-parking function is suspended when a suspension condition is fulfilled during a series of operation of the automated-parking function, but once the suspension condition is canceled in this case, the series of operation of the automated-parking function is resumed from the point where the operation has been suspended. The suspension condition includes the brake pedal (not shown) being operated. 
     Further, there may be a case where the vehicle  100  is found to hinder another vehicle from moving ahead. The driver of the vehicle  100  then shifts the position of the shift level  64  from the D-range to the R-range. This cancels the automated-parking function and the selection screen  81  in  FIG. 11  is displayed on the touch panel  32 . Selecting the cancel switch  83  on this screen is followed by the driver personally driving the vehicle  100  to move backward for letting said another vehicle to go away. Then, the driver operates the touch panel  32  or the like again to instruct activating the automated-parking function for starting over automated-parking. When the resume switch  82  is operated, the automated-parking function resumes from S 2 . 
     The automated-parking control unit  1  described above executes following control after the automated-parking function has been activated (after Yes in S 1 ) until parking operation to the desired parking position is started. That is, when the brake pedal (not shown) is operated (Yes in S 4 ), the automated-parking control unit  1  turns on the automated brake hold function (S 6 ). Accordingly, the braking force works even after the driver has stepped off the brake pedal (not shown), to prevent the vehicle  100  from unexpectedly moving. 
     The automated-parking control unit  1  requires following conditions in order to turn on the automated brake hold function (S 6 ). That is, the conditions are that available parking slots have been detected (S 3 ) and the driver has determined the desired parking position (Yes in S 5 ). In other words, the automated-parking control unit  1  allows the driver to move the vehicle  100  before the driver determines a desired parking position. Also, the automated-parking control unit  1  allows for preventing the vehicle  100  from unnecessarily moving after the driver has determined the desired parking position (Yes in S 5 ). 
     In addition, the automated-parking control unit  1  executes following control when the automated brake hold function has been turned on (S 6 ) and the automated-parking operation has been completed (Yes in S 12 ). That is, a history of activating the automated brake hold is recorded (S 10 , Yes in S 13 ). The automated-parking control unit  1  thus turns on the automated brake hold function (S 14 ) after the automated-parking operation has been completed (Yes in S 12 ). That is, when having been started with automated brake hold, the automated-parking ends with automated brake hold. This prevents the vehicle  100  from unexpectedly moving after the automated-parking operation has been completed (Yes in S 12 ). In contrast, even when the automated brake hold function has been turned on (S 6 ), the driver may operate the brake hold switch  45  to turn off the automated brake hold function. In this case, the automated brake hold function is kept off (No in S 13 ) after the automated-parking operation has been completed (Yes in S 12 ), as intended by the driver. 
     Further, when the brake hold switch  45  is canceled (Yes in S 9 ) while the driver is operating the brake pedal (not shown) (S 4 ), control is executed as follows. That is, the automated-parking control unit  1  turns off the automated brake hold function in this case to cancel braking (S 10 ), and starts automated-parking operation (S 10 ). Accordingly, from a state of the driver operating the brake pedal (S 4 ), braking is canceled and then the automated-parking operation is started (S 10 ), to give a secure feeling to the driver. 
     Still further, the automated-parking control unit  1  makes operation of the shift lever  64 , the steering wheel  72 , or the brake pedal (not shown) as an interruption condition (S 11 ). When the interruption condition is fulfilled, the automated-parking control unit  1  interrupts the automated-parking operation (S 16 ). This allows for giving higher priority to the driver&#39;s intention to interrupt the automated-parking operation than to continuing the operation. 
     Still further, the first elapsed time or second elapsed time being equal to or greater than a predetermined time is also an interruption condition (S 11 ). The first elapsed time is a time since the desired parking position has been decided (Yes in S 5 , S 7 ) until the brake hold switch  45  is operated (Yes in S 9 ). The second elapsed time is a time since the brake hold switch  45  has been operated (Yes in S 9 ) until operation on the brake pedal (not shown) is canceled (S 10 ). When the first elapsed time or second elapsed time is equal to or greater than the predetermined time, it is likely to happen that other vehicles  203  move in and/or out of the parking slots  202 . In other words, this allows for preventing automated-parking operation from being executed in a situation possibly different from that when the available parking slots have been searched for (S 3 ). 
     Still further, when automated-parking is interrupted (S 16 ), the resume conditions are defined (S 17 ). The resume conditions include the brake hold switch  45  being operated and a predetermined condition being fulfilled. The predetermined condition includes the resume switch  82  being operated in the selection screen  81 , as one of screens displayed on the touch panel  32  for the automated-parking function. The automated-parking control unit  1  is thus capable of resuming the automated-parking function not only with operation of the brake hold switch  45  but also with operation of the resume switch  82  or the like. 
     &lt;Brake Fluid Pressure Control Operation at Stationary Steering&gt; 
     Next, a description is given of brake fluid pressure control by the brake fluid pressure controller  19 .  FIG. 12  is a flowchart of brake fluid pressure control, at stationary steering, by the brake fluid pressure controller  19 .  FIG. 12  shows a subroutine of the process in  FIGS. 5 and 6 , indicated as step S 100 .  FIG. 13  is a top view of the parking area, to illustrate the brake fluid pressure control by the brake fluid pressure controller  19 . 
     The automated-parking controller  11  (see  FIG. 1 ) of the automated-parking control unit  1  controls the above-described system to cause the vehicle  100  to turn right with automated steering (see arrow “a” in  FIG. 13 ) so as to move forward with the D-range, as indicated by the arrow  223  in  FIG. 13 , and then suspend at the reverse steering position  222 . The controller then causes the vehicle  100  to execute stationary steering (steering while the vehicle being in suspension) after the suspension at the reverse steering position  222  (while the brake hold being in operation), as shown in  FIG. 13 . Next, the automated-parking controller  11  causes the vehicle  100  to turn left with automated steering (see arrow “b” in  FIG. 13 ) so as to move backward with the R-range, as indicated by the arrow  224  in  FIG. 13 , into the available parking slot  202   a  as the desired parking position, and then to stop. 
     After a subroutine call in step  100  in  FIG. 5 , the automated-parking control unit  1  determines in S 101  whether or not stationary steering has been started. That is, a determination is made for a timing of stationary steering after suspension at the predetermined position (while the brake hold being in operation) in the series of operation of the automated-parking function. When stationary steering has not been started (No in S 101 ), the processing returns to step S 100  in  FIG. 5 . When stationary steering has been started (Yes in S 101 ), the automated-parking control unit  1  determines in S 102  whether a road surface of a course of movement is downhill or not, based on output of the gradient sensor  26 . Note that the vehicle  100  easily moves on an uphill or downhill road, as compared with a case on a flat road, to have no need to consider a longitudinal orientation of the vehicle  100  such that a front vehicle portion is on a downhill side or a rear vehicle portion is on a downhill side. When the road surface of the course of movement is not downhill (No in S 102 ), the brake fluid pressure controller  19  increases a brake fluid pressure, which has been constant, to a first brake fluid pressure and then proceeds to S 105 . 
     When the road surface of the course of movement is downhill (Yes in S 102 ), the brake fluid pressure controller  19  increases a brake fluid pressure to a second brake fluid pressure, which is higher than the first brake fluid pressure, and then proceeds to S 105 . Here, desired brake fluid pressures as the first and second brake fluid pressures may be based on brand-new brake pads (the first and second brake pads  311 ,  312  in  FIG. 3 ). 
     The automated-parking control unit  1  determines in S 105  whether or not the stationary steering has been completed. When the stationary steering has not been completed (No in S 105 ), the processing returns to S 102  as described above. When the stationary steering has been completed (Yes in S 105 ), the brake fluid pressure controller  19  restores the brake fluid pressure increased to the first or second brake fluid pressure, i.e., the original, constant (predetermined) brake fluid pressure, and then the processing returns to S 100  of the flowchart in  FIG. 5 . 
     As described above, the automated-parking control unit  1  (parking assist system) of the present embodiment for the vehicle  100  (see  FIG. 1 ) includes: the environment recognizer  1   a  to recognize environment of the vehicle  100 ; the behavior controller  1   b  to execute behavior control inclusive of steering and acceleration/deceleration, based on recognized information; the brake hold instructor  13  (suspension hold controller) to suspend the vehicle  100  with the behavior control and hold the vehicle suspended until receiving behavior-related operation by a driver; the automated-parking controller  11  to set the reverse steering position  222  (see  FIGS. 10 and 13 ), based on a current position of the vehicle  100  and a desired parking position decided by the driver, between the current position and the desired parking position, move from the current position to the reverse steering position  222 , and execute stationary steering at the reverse steering position  222 ; and the brake fluid pressure controller  19  to increase a braking force of the vehicle  100  (increase a brake fluid pressure, for example) when stationary steering is executed at the reverse steering position  222 . 
     With this configuration, a brake fluid pressure of the vehicle in question is increased when stationary steering is executed at the reverse steering position for parking, to strongly press the brake pads  311 ,  312  against the disk  320  to prevent the brake pads  311 ,  312  from making a brake noise. Uncomfortable feeling or discomfort due to a brake noise at stationary steering is prevented during automated steering by the parking assist system. 
     Incidentally, Patent Document 1 discloses braking force control to decrease a brake fluid pressure at the time of stationary steering and, when a driver intends to personally brake while braking force control being in operation, increases the brake fluid pressure to the original brake fluid pressure. Patent Document 1 is not for preventing a brake noise from being made at stationary steering during automated steering by a parking assist system. 
     In contrast, the present embodiment increases the brake fluid pressure of the vehicle  100  at the reverse steering position  222 , at the time of stationary steering while the automated-parking control being in operation, and this control is opposite to the technique used by Patent Document 1. The present embodiment prevents a brake noise at stationary steering while automated steering being in operation, even with some burden to a steering device, to have advantageous effects of keeping quietness within the compartment, eliminating uncomfortable feeling or discomfort due to a brake noise, and enhancing product appeal. 
     Here, the vehicle  100  is one having a driving source disposed on an opposite side in a vehicle front-rear direction to the steering wheel, such as a rear-wheel drive vehicle. Such a vehicle has a smaller load applied to the steering wheel at the time of stationary steering, as compared with a vehicle having a driving source disposed on the same side in the vehicle front-rear direction as the steering wheel, to have a load to the steering device mitigated while the present control being in operation. That is, the vehicle  100  is desirably a vehicle having a driving source disposed on an opposite side in the vehicle front-rear direction to the steering wheel. 
     The automated-parking controller  11  of the present embodiment shifts the position in the shift range of the transmission mounted on the vehicle  100  from the D-range to the R-range at the reverse steering position  222 , based on the shift position data from the shift position sensor  25 . In this manner, the vehicle  100  is moved forward as indicated by the arrow  223 , is suspended at the reverse steering position  222 , and is moved backward as indicated by the arrow  224  into the parking slot  202   a  for parking, as shown in  FIG. 13 . 
     When braking operation is canceled by the driver, the automated-parking controller  11  of the present embodiment starts moving the vehicle toward the desired parking position. Before the driver determines a desired parking position, the controller allows the vehicle  100  to be driven and moved by the driver. After the driver has determined the desired parking position (Yes in S 5 ), the controller inhibits the vehicle  100  from being unnecessarily moved. 
     The brake fluid pressure controller  19  of the present embodiment executes brake fluid pressure control to increase a brake fluid pressure from a predetermined pressure to a desired brake fluid pressure, and the desired brake fluid pressure is varied depending on a steering speed and/or a steering angle at the stationary steering. As the desired brake fluid pressure is varied depending on a steering speed and/or a steering angle at the stationary steering, a brake noise is prevented while a braking force is exerted according to a condition of stationary steering. 
     With the present embodiment, the vehicle  100  is provided with the gradient sensor  26  to detect a gradient of a road surface on which the vehicle  100  is located, and the brake fluid pressure controller  19  varies a brake fluid pressure, based on a gradient of a course of movement detected by the gradient sensor  26 . For example, when the gradient is of a downhill or an uphill, the brake fluid pressure controller  19  increases the brake fluid pressure. As the brake fluid pressure is varied based on a gradient of a course of movement in this manner, a brake noise is prevented while a braking force is exerted according to a gradient of a course of movement. 
     The vehicle  100  (see  FIG. 1 ) is provided with a disk brake  300  to press brake pads  311 ,  312  (see  FIG. 3 ) against a disk  320  by way of oil pressure to brake the vehicle  100 , and the brake fluid pressure controller  19  of the present embodiment executes brake fluid pressure control to increase a brake fluid pressure from a constant pressure (predetermined pressure) to the desired brake fluid pressure. The desired brake fluid pressure is set to one with the brand-new brake pads as standards. That is, a brand-new brake pad includes a friction material having a larger thickness to easily make a brake noise. Once the desired brake fluid pressure is set to be used for increasing a brake fluid pressure with the brand-new brake pad as standards, a brake noise would be less likely made with a decreasing thickness of the friction material due to aging, to allow for preventing a brake noise regardless of aging of the disk brake  300 . 
     Modifications 
     As shown in  FIG. 13 , the present embodiment causes the vehicle  100  to move forward with the D-range, suspend at the reverse steering position  222 , execute stationary steering after the suspension at the reverse steering position  222  (while the brake hold being in operation), move backward with the R-range into the desired parking position, and stop. As a modification, the desired brake fluid pressure may be varied depending on a steering speed and/or a steering angle at the stationary steering to vary an increasing amount of the brake fluid pressure. Specifically, when a steering speed is small or a steering angle is small, the desired brake fluid pressure is less increased. When configured to vary the desired brake fluid pressure depending on a steering speed and/or a steering angle at the stationary steering, as described above, the device would prevent a brake noise more effectively while a load to the steering device being reduced. 
     The embodiment hereinabove has been described for the purpose of illustrating the present invention in detail, and the present invention is not limited to one having all the components as described above. Parking assist is only required to increase a brake fluid pressure, and can be used not only for moving in but also for moving out. In addition, a case has been described above in which automated parking operation involves moving the vehicle  100  backward into the parking slot, but it may involve moving the vehicle  100  forward into the parking slot. Alternatively, the driver may be allowed to select between moving backward or moving forward. 
     LIST OF REFERENCE SIGNS 
       1 : automated-parking control unit (parking assist system),  1   a:  environment recognizer,  1   b:  behavior controller,  11 : automated-parking controller (suspension hold controller),  11   a:  available parking position detector,  11   b:  desired parking position detector,  12 : parking activation instruction detector,  13 : brake hold instructor (suspension hold controller),  14 : brake hold continuation determiner,  15 : brake hold cancel instructor,  16 : first parking operation interrupter,  17 : second parking operation interrupter,  18 : resume instructor,  19 : brake fluid pressure controller,  25 : shift position sensor,  26 : gradient sensor (road surface gradient detector),  44 : automated brake hold control unit (automated brake hold controller),  45 : brake hold switch (cancel instruction controller),  64 : shift lever,  72 : steering wheel,  82 : resume switch (resume instruction receiver),  100 : vehicle,  202   a:  desired parking slot,  222 : reverse steering position,  300 : disk brake,  311 : first brake pad, and  312 : second brake pad.