Patent Publication Number: US-2020298834-A1

Title: Vehicle Control Device and Automatic Parking System

Description:
TECHNICAL FIELD 
     The present invention relates to a vehicle control device and an automatic parking system. 
     BACKGROUND ART 
     In recent years, vehicle control devices that automatically drive vehicles have been developed. As examples thereof, there are known inter-vehicle distance keeping travel control that maintains a constant inter-vehicle distance from a preceding vehicle that travels on the front side while recognizing the front of the vehicle and travel lane keeping control that performs travel control so as not to deviate from a travel lane of a vehicle, for example. Furthermore, as an advanced type thereof, studies have been conducted on automated valet parking that automatically parks a vehicle in a parking facility of a building by automatic driving without being operated by a passenger. 
     In the automated valet parking, instruction information, such as a vehicle entry/exit instruction with respect to the parking facility, a vehicle stop instruction, and a vehicle start instruction, is transmitted to the vehicle by means of wireless communication which is used for C2X (Car-to-X)/V2X (Vehicle-to-X) and the like as a mobile phone network and road-to-vehicle/vehicle-to-vehicle communication from a control center. The vehicle stops, starts, and performs parking in the parking facility by automatic driving according to the instruction information. For example, when the instruction information is parking of the vehicle, the vehicle travels to a designated parking position by automatic driving and is parked at the designated parking position. 
     In the wireless communication, however, a direct wave transmitted from the control center and an interference wave overlap with each other at a reception site to cancel each other so that a null point is generated. At this null point, the interference wave changes due to a change in an environment of a parked vehicle or the like, and the null-point position also changes due to this change. Further, it is difficult for the control center to perform transmission and reception with the vehicle by wireless communication at the null point. For example, when a stop instruction is received from the control center for a certain region before the vehicle is parked at the designated parking position, the vehicle during the automatic driving is stopped. At this time, if the vehicle stops at the null point, the wireless communication is not possible even if there is a start instruction from the control center, and thus, the vehicle fails to restart and stays there. 
     PTL 1 describes an in-vehicle computer that transmits null point position information to a vehicle in advance and performs automatic parking based on the position information and calculates a movement trajectory of the vehicle so as to avoid a null-point position. 
     CITATION LIST 
     Patent Literature 
     PTL 1: JP 2009-239744 A 
     SUMMARY OF INVENTION 
     Technical Problem 
     With the technique described in PTL 1, it is difficult to avoid the null-point position when a parking facility is not spacious. 
     Solution to Problem 
     The vehicle control device according to the present invention includes: a wireless communication unit that acquires a null point indicating a position at which wireless communication is poor in a parking facility and instruction information for controlling a vehicle in the parking facility from a control center by means of wireless communication; and a control unit that moves the vehicle until the vehicle has escaped the null point and then stops the vehicle when the instruction information acquired by the wireless communication unit is an instruction for stopping the vehicle and an instructed stopping position is the null point. 
     An automatic parking system according to the present invention includes a vehicle control device and a control center that performs wireless communication with the vehicle control device. 
     Advantageous Effects of Invention 
     According to the present invention, it is possible to prevent the vehicle from stopping at the null point even when the parking facility is not spacious. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG. 1  is a configuration diagram of a vehicle. 
         FIG. 2  is a configuration diagram of a control center. 
         FIG. 3  is a diagram illustrating a position of a vehicle in a parking facility. 
         FIG. 4  is a flowchart illustrating an operation of the vehicle. 
         FIG. 5  is a flowchart illustrating an operation of the vehicle when detecting an obstacle. 
     
    
    
     DESCRIPTION OF EMBODIMENTS 
     Hereinafter, embodiments of the present invention will be described with reference to the drawings. 
       FIG. 1  is a configuration diagram of a vehicle  100 . The vehicle  100  includes various external-environment sensors  101 , various actuators  102 , an automatic driving control unit  103 , a host vehicle position estimation unit  104 , a wireless communication unit  105 , an antenna  106 , and a null point determination unit  107 . 
     The various external-environment sensors  101  include a camera, a millimeter wave radar, an infrared radar, and the like in order to detect an obstacle and the like and enable automatic driving of the vehicle  100 . 
     The various actuators  102  include an engine that drives the vehicle, a brake that brakes the vehicle, and the like, and control the power of the vehicle  100 . 
     The automatic driving control unit  103  controls the various actuators  102  based on information from the various external-environment sensors  101  and the like, and causes the vehicle  100  to enter or exit a parking facility by automatic driving. 
     The host vehicle position estimation unit  104  estimates a current position of the vehicle  100  from information such as a global positioning system (GPS), a Global Navigation Satellite System (GNSS), and a gyro sensor, and outputs the information on the current position to the automatic driving control unit  103  and the like. 
     The wireless communication unit  105  performs wireless communication with a control center  200 , which will be described later, via the antenna  106 , and receives instruction information such as stop, start, entry, and exit of the vehicle  100  from the control center  200 , for example. Further, a detailed map of the parking facility and information indicating a null-point position are received from the control center  200 . The wireless communication unit  105  transmits/receives information by means of wireless communication which is used for C2X (Car-to-X)/V2X (Vehicle-to-X) or the like as a mobile phone network or road-to-vehicle/vehicle-to-vehicle communication. 
     Further, the wireless communication unit  105  includes an RSSI detection unit  115 . The RSSI detection unit  115  detects a reception signal intensity indicator (RSSI) of the wireless communication unit  105 . 
     The null point determination unit  107  stores the null point received from the control center  200  via the wireless communication unit  105 . The null point is position information represented by latitude, longitude, and the like. Further, the null point determination unit  107  acquires the current position of the vehicle  100  from the host vehicle position estimation unit  104 . Then, the null point determination unit  107  acquires the reception signal intensity detected by the RSSI detection unit  115 , and determines that the vehicle  100  has escaped the null point if the reception signal intensity exceeds a threshold along with the movement of the vehicle  100  from the null point. This determination result is output to the automatic driving control unit  103 , and driving control of the vehicle  100  is performed according to the determination result. The reception signal intensity detected by the RSSI detection unit  115  is sequentially transmitted to the control center  200  via the wireless communication unit  105  together with the current position information acquired by the host vehicle position estimation unit  104 . 
       FIG. 2  is a configuration diagram of the control center  200 . The control center  200  includes a map information storage unit  201 , a null point storage unit  202 , a management control unit  203 , a wireless communication unit  204 , and an antenna  205 . 
     The map information storage unit  201  stores the detailed map of the parking facility. This detailed map also includes arrangement information of vehicles parked in the parking facility. 
     The null point storage unit  202  stores the null point of the parking facility. A direct wave and an interference wave of wireless communication are different depending on the arrangement of vehicles parked in the parking facility, and thus, the null point of the parking facility is also different. The null point storage unit  202  stores the null point of the parking facility in association with the arrangement information of vehicles parked in the parking facility. Then, when the vehicle  100  enters or exits, a null point corresponding to current arrangement information of vehicles parked in the parking facility is read out. 
     The management control unit  203  instructs entry, exit, stop, start, and the like to the vehicle  100  so as to achieve the consideration of safety and smooth operation in response to the arrangement of vehicles parked in the parking facility and the movement of other vehicles. Further, the management control unit  203  accumulates the reception signal intensity transmitted from the vehicle  100  and the position information thereof, and updates the null point corresponding to the vehicle arrangement information. Specifically, mapping is performed including a site where the reception signal intensity is equal to or greater than the threshold and a site where the reception signal intensity is less than the threshold so that information has not been transmitted, and the null-point position indicating the position where the wireless communication in the parking facility is poor is determined on the map. Then, the null point is stored in the null point storage unit  202  in association with the vehicle arrangement information. 
     The wireless communication unit  204  performs wireless communication with the vehicle  100  via the antenna  205 , and transmits instruction information such as stop, start, entry, and exit from the control center  200  to the vehicle  100 , for example. Further, the control center  200  transmits the detailed map of the parking facility and the information indicating the null-point position. 
     Next, the operation of the present embodiment will be described with reference to  FIGS. 3 to 5 . 
       FIG. 3  is a view illustrating vehicle positions in a parking facility  301 , and illustrates an outline of vehicle parking using automated valet parking. 
     In the parking facility  301 , the control center  200  is installed near a carriage porch  303 , vehicles  100 - b  to  100 - d  are parked, and a vehicle  100 - e  is traveling. The vehicle  100 - a  is stopped near the carriage porch  303  and waits for the entry. Each of the vehicles  100 - a  to  100 - e  has the configuration illustrated in  FIG. 1 . Each of the vehicles  100 - a  to  100 - e  performs wireless communication with the control center  200 , travels in the parking facility  301  by automatic driving, and is caused to enter or exit a parking spot by automated valet parking. 
     In the automated valet parking, a driver stops the vehicle  100 - a  at a stopping position  304  near the carriage porch  303  and gets off. If another passenger is present, the passenger also gets off in the same manner. The driver instructs the control center  200  to start the automated valet parking using a mobile phone or the like. This instruction may be made via a voice, or a command may be transmitted. 
     The control center  200  searches for a route  310  to a parking position  307  and instructs the vehicle  100 - a  to start. When encountering the other vehicle  100 - e  at a position  305  in the middle of the route  310 , the vehicle  100 - a  receives a stop instruction from the control center  200 . At this time, the vehicle  100 - a  determines whether or not the position  305  is a null point, and stops at the position  305  if it is not the null point. When it is determined as the null point, the vehicle  100 - a  moves to a position where the vehicle  100 - a  has escaped the null point as will be described later. 
     Thereafter, the vehicle  100 - a  further advances along the route  310  upon receiving a start instruction from the control center  200 . 
     Further, it is assumed that a stop instruction is received from the control center  200  at a position  308  near the parking position  307 . If the position  308  corresponds to the null point provided from the control center  200 , the vehicle  100 - a  does not stop at the position  308 , and the vehicle  100 - a  moves at the slowest speed. Further, if the reception signal intensity detected by the RSSI detection unit  115  of the vehicle  100 - a  is equal to or greater than the threshold, it is determined that the vehicle  100 - a  has escaped the null point, and the vehicle  100 - a  stops at the position  309 . Thereafter, the vehicle  100 - a  is parked at the designated parking position  307  upon receiving a start instruction for parking. 
     When the vehicle  100 - a  is parked at the designated parking position  307 , the RSSI detection unit  115  of the vehicle  100 - a  detects the reception signal intensity and confirms that the reception signal intensity is equal to or greater than the threshold. If the reception signal intensity is equal to or greater than the threshold, parking is completed at this position. When the reception signal intensity is less than the threshold, the vehicle  100 - a  moves to a position where the reception signal intensity is equal to or greater than the threshold, for example, a position  309 , asks the control center  200  to change the parking position, and changes the parking position according to an instruction from the control center  200 . 
     During the traveling along the route  310 , the vehicle  100 - a  sequentially transmits the reception signal intensity detected by the RSSI detection unit  115  to the control center  200  by means of wireless communication together with the current position information. The management control unit  203  accumulates the reception signal intensity transmitted from the vehicle  100  and the position information thereof, and updates the null point corresponding to the vehicle arrangement information. This corresponds to the case where the null point changes depending on the arrangement of the other parked vehicles  100 - b  to  100 - d . Thus, the database of the null point storage unit  202  of the control center  200  is updated, and the relationship between the vehicle arrangement information and the null point is learned to determine the null point. 
       FIGS. 4 and 5  are flowcharts illustrating operations at the time of entry and exit of the vehicle  100 . These flowcharts illustrate processing operations of the automatic driving control unit  103 , the null point determination unit  107 , and the like of the vehicle  100 . Incidentally, programs illustrated in these flowcharts may be realized by execution using a computer that includes a CPU, a memory, and the like. Further, these programs may be supplied as various forms of computer-readable computer program products such as a recording medium and a data signal (carrier wave). 
     A driver and a passenger stop the vehicle  100  near the carriage porch  303  and get off. Then, in Step  401  of  FIG. 4 , the driver instructs the control center  200  to start automated valet parking using a mobile phone or the like. 
     In Step  402 , the vehicle  100  receives a parking position, a detailed map of a parking facility, and a null point from the control center  200 . 
     In Step  403 , the vehicle  100  stands by until a start instruction is received from the control center  200 . When the start instruction is received, the process proceeds to Step  404 . 
     In Step  404 , the vehicle  100  generates the travel route  310  based on the parking position and the detailed map of the parking facility, and starts traveling along the travel route  310 . 
     In Step  405 , the vehicle  100  controls the various actuators  102  based on information from the various external-environment sensors  101  and travels along the travel route  310  by automatic driving. Then, the current position information and the reception signal intensity (RSSI) are sequentially transmitted to the control center  200 . 
     In Step  405 , when the vehicle  100  detects an obstacle using the various external-environment sensors  101 , a processing operation illustrated in  FIG. 5 , which will be described later, is performed. 
     In Step  406 , it is determined whether the vehicle  100  has reached a site before the parking position. If the vehicle  100  has not reached the site before the parking position, it is determined in Step  407  whether the vehicle  100  has received a stop instruction from the control center  200 . This stop instruction is appropriately transmitted from the control center  200  in order for operation management in the parking facility. If the stop instruction has not been received, the process returns to Step  405 , and the vehicle  100  moves along the travel route  310  in the parking facility while repeating the processing up to Step  407 . 
     If the vehicle  100  has received the stop instruction from the control center  200  in Step  407 , the process proceeds to Step  408 . In Step  408 , it is determined whether the current position of the vehicle  100  is the null point. Specifically, it is determined whether the current position indicated by the host vehicle position estimation unit  104  corresponds to the null point received from the control center  200  and stored in the null point determination unit  107 . If the current position is not the null point, the process proceeds to Step  409  and the vehicle  100  stops at the current position, that is, the stopping position. Then, the process returns to Step  403  and the vehicle  100  stands by until receiving a start instruction from the control center  200 . 
     If it is determined in Step  408  that the current position of the vehicle  100  is the null point, the process proceeds to Step  410 . In Step  410 , the vehicle  100  moves at the slowest speed to an area where the reception signal intensity becomes equal to or greater than the threshold while confirming the reception signal intensity detected by the RSSI detection unit  115 . That is, the vehicle  100  moves forward or backward until escaping the null point. As a result, it is possible to avoid a situation where the vehicle  100  stops at the null point, it becomes difficult to perform the wireless communication thereafter, and the vehicle  100  stays on the travel route  310 . 
     When the vehicle  100  has escaped the null point, the process proceeds to Step  411 . In Step  411 , the vehicle  100  stops and transmits information indicating the stopping position to the control center  200 . Then, the process returns to Step  403  and the vehicle  100  stands by until receiving a start instruction from the control center  200 . 
     If it is determined in Step  406  that the vehicle  100  has reached the site before the parking position, the process proceeds to Step  412 . In Step  412 , the vehicle  100  parks at the parking position by automatic driving, and detects whether the reception signal intensity at this parking position is less than the threshold. If the reception signal intensity is less than the threshold, the process proceeds to Step  413 . In Step  413 , the vehicle  100  exits the parking position and moves until the vehicle  100  has escaped the null point. Then, the vehicle  100  moves, at the slowest speed, to the area where the reception signal intensity is equal to or greater than the threshold and stops, and transmits a parking position change request to the control center  200 . As a result, it is possible to avoid a situation where the vehicle  100  is parked at the null point, it is difficult to perform the wireless communication thereafter, and it becomes difficult to cause the vehicle  100  to exit the parking spot. 
     After the process of Step  413 , the vehicle  100  returns to the process of Step  402  and receives information such as a new parking position from the control center  200 . 
     When the vehicle  100  is parked at the parking position by automatic driving and the reception signal intensity is equal to or greater than the threshold in Step  412 , the process proceeds to Step  414 . In Step  414 , the vehicle  100  transmits the parking position information and the reception signal intensity to the control center  200 . In the subsequent Step  415 , the vehicle  100  stops a power source such as the engine. 
       FIG. 5  is a flowchart illustrating an operation of the vehicle when detecting an obstacle.  FIG. 4  illustrates a detailed processing operation when the obstacle is detected on the travel route  310  in the parking facility in the processing illustrated in Step  405  of  FIG. 4 . 
     When the vehicle  100  detects an obstacle by the various external-environment sensors  101  during the traveling along the travel route  310  and the obstacle is removed, the various external-environment sensors  101  recognize that the obstacle has disappeared, and the traveling is started again. However, if the obstacle is not removed even after a lapse of a certain period of time, the processing operation illustrated in  FIG. 5  is started. Incidentally, this corresponds to a case where a road cone or the like is placed on the travel route  310  intentionally or unintentionally, for example, as such an obstacle. 
     If the obstacle is not removed even after the lapse of the certain period of time, it is determined whether the stopping position of the vehicle  100  is the null point in Step  415  in  FIG. 5 . Specifically, it is determined whether the current position indicated by the host vehicle position estimation unit  104  corresponds to the null point received from the control center  200  and stored in the null point determination unit  107 . If the stopping position is the null point, the process proceeds to Step  425 , and the vehicle  100  gradually moves forward or backward to a position where the obstacle can be avoided independently of a command from the control center  200 . 
     In the subsequent Step  435 , the vehicle  100  confirms the reception signal intensity using the RSSI detection unit  115  to determine whether the vehicle  100  has moved to the area where the reception signal intensity is equal to or greater than the threshold, that is, whether the vehicle  100  has escaped the null point. If the vehicle  100  has not escaped the null point, the process returns to Step  425 , and the vehicle  100  gradually moves to a position where the obstacle can be avoided. 
     If it is determined in Step  435  that the vehicle  100  has escaped the null point, the process proceeds to Step  445 , and the vehicle  100  stops in Step  445 . As a result, it is possible to avoid a situation where the vehicle  100  stops at the null point, it becomes difficult to perform the wireless communication thereafter, and the vehicle  100  stays on the travel route. 
     Then, the vehicle  100  notifies the control center  200  of that movement is not possible due to the obstacle in the subsequent Step  455 . Incidentally, the control center  200  having received the notification takes measures such as dispatching a staff and re-searching a travel route that avoids the obstacle. 
     Incidentally,  FIGS. 4 and 5  illustrate the operation at the time of entry of the vehicle  100 , the same operation is performed even at the time of exit of the vehicle  100 . That is, at the time of exit, the vehicle  100  is caused to automatically travel from a parking position to a carriage porch position. In this case, control is performed such that the vehicle  100  moves until escaping the null point by the same processing as described in Steps  401  to  411  of  FIG. 4  and Steps  415  to  455  of  FIG. 5 . 
     According to the present embodiment, when there is the stop instruction from the control center or the obstacle is present on the route during the automated valet parking, the vehicle does not stop near the null point, and thus, it is possible to reliably receive a subsequent start instruction from the control center, and the vehicle can be prevented from staying on the travel route in the parking facility. 
     According to the above-described embodiment, the following operational effects are obtained. 
     (1) The vehicle control device includes: the wireless communication unit  105  that acquires the null point indicating the position at which wireless communication is poor in the parking facility  301  and the instruction information for controlling the vehicle  100  in the parking facility  301  from the control center  200  by means of wireless communication; and the automatic driving control unit  103  that moves the vehicle  100  until the vehicle  100  has escaped the null point and then stops the vehicle  100  when the instruction information acquired by the wireless communication unit  105  is the instruction for stopping the vehicle  100  and the instructed stopping position is the null point. As a result, it is possible to prevent the vehicle  100  from stopping at the null point even when the parking facility  301  is not spacious. 
     (2) The vehicle control device includes the null point determination unit  107  that determines the escaping the null point based on whether the reception signal intensity received from the control center  200  is equal to or greater than the threshold. 
     As a result, it is possible to detect that the vehicle  100  has escaped the null point and to avoid the stop of the vehicle  100  at the null point. 
     (3) The automatic driving control unit  103  changes the parking position to a new parking position when the instruction information acquired by the wireless communication unit  105  is the instruction to park the vehicle  100  and the parking position is the position less than the reception signal intensity. As a result, it is possible to avoid the parking of the vehicle  100  at the null point. 
     (4) The vehicle control device further includes the various external-environment sensors  101  that detect an obstacle of the vehicle, and the automatic driving control unit  103  moves the vehicle  100  until the vehicle  100  has escaped the null point while avoiding the obstacle and then stops the vehicle  100  when the obstacle does not move after the various external-environment sensors  101  detect the obstacle and the vehicle  100  stops at the null point. As a result, it is possible to prevent the vehicle  100  from stopping at the null point even when the obstacle is present. 
     (5) An automatic parking system includes the vehicle  100  and the control center  200  that performs wireless communication with the vehicle  100 . The vehicle  100  detects the reception signal intensity received from the control center  200  and transmits the reception signal intensity to the control center  200 . The control center  200  accumulates the reception signal intensity and the arrangement information of the vehicles parked in the parking facility  301 , and stores the null point determined based on the reception signal intensity and the arrangement information of the parked vehicles in the null point storage unit  202 . As a result, the control center  200  can update the null point according to the reception signal intensity and the arrangement information of the parked vehicles. 
     The present invention is not limited to the above-described embodiments, and other modes, which are conceivable inside a scope of a technical idea of the present invention, are also included in a scope of the present invention as long as characteristics of the present invention are not impaired. 
     REFERENCE SIGNS LIST 
     
         
           100  vehicle 
           101  various external-environment sensors 
           102  various actuators 
           103  automatic driving control unit 
           104  host vehicle position estimation unit 
           105  wireless communication unit 
           107  null point determination unit 
           200  control center 
           201  map information storage unit 
           202  null point storage unit 
           203  management control unit 
           204  wireless communication unit