Patent Publication Number: US-2022229153-A1

Title: Abnormality diagnosis system

Description:
BACKGROUND OF THE INVENTION 
     The present invention relates to an abnormality diagnosis system that diagnoses abnormality of a detector mounted to a vehicle. 
     In recent years, vehicles traveling on roads each include a driver-assistance system and a detector that is used to realize automated driving. Examples of such a detector are a radar sensor, an imaging sensor, and a Lidar unit. Output information of these detectors is used to observe vehicle surrounding information including obstacles such as another vehicle and a pedestrian in addition to a travelable area and a road. 
     SUMMARY OF THE INVENTION 
     In order to guarantee safe travel of the vehicle, it is desired to be able to detect an actuation state of the detector. In the case where the detector is brought into a state where the actuation state thereof cannot be detected, a vehicle system needs to handle such a state. For example, the vehicle system needs to impair system performance or stop a system function. 
     Conventionally, the detector detects the state of itself on the basis of an internal signal and an observation result. For example, the detector determines whether the surrounding environment is stably detected when the vehicle surrounding environment is changed, or when the vehicle surrounding environment remains the same. For example, the detector determines that the surrounding environment cannot be detected due to dirt that covers a front surface of the detector or the like when the detected surrounding environment is not changed, or when it is indicated that the surrounding environment is “null”. 
     However, such a conventional determination method possibly produces an erroneous diagnosis. For example, in the conventional determination method, the detector determines that the surrounding environment cannot be detected even in the case where the surrounding environment actually remains the same or where nothing exists in the surrounding environment. Such an erroneous diagnosis is possibly made while the vehicle travels on a bridge over a wide river or a large lake or a bridge including low guardrails. 
     The present invention has been made in view of the above problem and therefore provides an abnormality diagnosis system capable of improving reliability of a diagnosis result on a state of a detector mounted to a vehicle. 
     According to an aspect of the present invention, an abnormality diagnosis system that diagnoses abnormality of a detector detecting surrounding information on a vehicle is provided. The abnormality diagnosis system includes: a positioning device; a storage device that stores map data containing data on an object existing on/above ground; and a control section that diagnoses presence or absence of the abnormality of the detector by comparing the map data and detection data obtained by the detector. 
     As it has been described so far, according to the present invention, it is possible to improve reliability of a diagnosis result on a state of the detector mounted to the vehicle. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a schematic view of a configuration example of an abnormality diagnosis system according to an embodiment of the present invention. 
         FIG. 2  is a flowchart of an example of processing executed by the abnormality diagnosis system according to the embodiment. 
         FIG. 3  is a flowchart of an example of processing for identifying an object detected by a radar sensor. 
         FIG. 4  is a flowchart of an example of abnormality determination processing executed by the abnormality diagnosis system according to the embodiment. 
         FIG. 5  is a schematic view of an example of a field of view from a vehicle. 
         FIG. 6  is a schematic view of an example of map data. 
     
    
    
     DETAILED DESCRIPTION 
     A detailed description will hereinafter be made on a preferred embodiment of the present invention with reference to the accompanying drawings. In the present specification and the drawings, components having the substantially same functional configuration will be denoted by the same reference sign, and thus a description thereon will not be repeated. 
     &lt;1. Configuration Example of Abnormality Diagnosis System&gt; 
     A description will be made on a configuration example of an abnormality diagnosis system  50  according to this embodiment with reference to  FIG. 1 . In the following embodiment, a description will be made on a radar sensor  20  as an example of a detector that detects vehicle surrounding environment. A vehicle is not particularly limited to an engine vehicle including an internal combustion engine as a drive source, an electrically-driven vehicle including an electric motor as the drive source, a hybrid vehicle including the internal combustion engine and the electric motor as the drive sources, and the like. 
       FIG. 1  is a schematic view of an system configuration of the vehicle that includes the abnormality diagnosis system  50 . The abnormality diagnosis system  50  includes a control section  51 , a storage device  55 , a Global Positioning System (GPS) receiver  59 , a network communication module  61 , and the radar sensor  20 . 
     The control section  51  is partially or entirely constructed of a microcontroller, an application specific integrated circuit (ASIC), a field-programmable gate array (FPGA), a microprocessor, another suitable electronic device, or the like. The control section  51  may partially or entirely be constructed of a member in which firmware or the like can be updated, or may partially or entirely be a program module or the like that is executed by a command from a central processing unit (CPU) or the like. 
     The control section  51  may be configured to execute a command that corresponds to one or plural types of software programs.  FIG. 1  illustrates an example of the abnormality diagnosis system  50  using the single control section  51 . However, as the control section  51 , the plural control sections may be configured in a mutually communicable manner. Some or all functions provided by the storage device  55 , the GPS receiver  59 , or the network communication module  61  may be integrated with functions of the control section  51  by using hardware or software. 
     The control section  51  can obtain information on a travel state of the vehicle including a vehicle speed as well as a steering angle or a turning angle. These types of the information may directly be input from a vehicle speed sensor, a steering angle sensor, and the like, or may be input from another control section mounted to the vehicle via a communication bus such as a controller area network (CAN). 
     The GPS receiver  59  receives a GPS signal in order to determine a current position of itself on the earth. The GPS receiver  59  is an aspect of a positioning device. The network communication module  61  is connected to the control section  51  and allows the control section  51  to exchange data by using one or plural wired or wireless digital networks. The storage device  55  includes a storage element such as random access memory (RAM) or read only memory (ROM). In addition, the storage device  55  may include a storage device such as a hard disk drive (HDD) or a storage. 
     The storage device  55  stores map data  70 . The map data  70  contains not only data on roads but also data on actual positions of lanes of the roads and objects that exist on the roads or adjacent to the roads on/above the ground. The map data  70  is map data used for automated driving control, for example. An automated driving controller, which is not illustrated, refers to the map data  70  to set a travel position at which the vehicle can safely travel. 
     The objects existing on/above the ground include unmoving objects that exist near the road, and examples of such objects are a traffic light, a traffic sign, a guardrail, another road crossing the road, an elevated bridge, a pole of a fence, a barrier, a land bridge, a curbstone, a parked vehicle, and a manhole cover. In this embodiment in which an abnormality diagnosis on the radar sensor  20  is made, the data on the objects existing on/above the ground contains three-dimensional data. The three-dimensional data is data that represents a partial or entire outer shape of each of the objects existing on/above the ground. 
     The map data  70  can be updated by using data that is provided from a map data generator on the outside of the vehicle. For example, a map data generator  1  obtains surrounding environment data transmitted from the plural vehicles, updates the three-dimensional data on the objects that exist on/above the ground at positions on the map data, and provides such data to the vehicle that can use the system. In this case, the surrounding environment data transmitted from each of the vehicles may be data on objects that are obtained by the detector in each of the vehicles, such as the radar sensor  20 , detecting the surrounding environment. The map data  70  may be updated periodically or non-periodically. 
     The radar sensor  20  is a detector that has an emitting section emitting a radar wave and a receiving section receiving a reflected wave of the radar wave, and detects the object on the basis of the radar wave and the reflected wave. For example, the radar sensor  20  may be a detector capable of emitting the appropriate radar wave such as an intermediate-distance radar sensor or a millimeter-wave radar sensor. 
     The control section  51  has a function as a control section that diagnoses presence or absence of abnormality of the radar sensor  20 . The control section  51  diagnoses the presence or the absence of the abnormality of the radar sensor  20  by comparing the map data  70  and detection data on the object obtained by the radar sensor  20 . More specifically, the control section  51  determines whether the radar sensor  20  has detected the object on the basis of the three-dimensional data contained in the map data  70 , and thereby diagnoses the presence or the absence of the abnormality of the radar sensor  20 . 
     For example, the control section  51  may diagnose the presence or the absence of the abnormality of the radar sensor  20  on the basis of an error between the three-dimensional data on the object that exists around the position of the vehicle and is contained in the map data  70  and plural detection points detected by the radar sensor  20 . 
     More specifically, the control section  51  identifies a GPS position that is identified by the GPS receiver  59 , and determines the current position of the vehicle on the map data  70 . At this time, the control section  51  may set a specified error to determine the position of the vehicle on the map data  70 . After determining the position of the vehicle on the map data  70 , the control section  51  identifies the object that exists within a range, which is set in advance, around the position of the vehicle. 
     In addition, the control section  51  processes the detection data on the object that is detected by the radar sensor  20 , and thereby calculates an absolute speed of the object. For example, after calculating a relative speed between the object, which is detected by the radar sensor  20 , and the vehicle, the control section  51  subtracts the vehicle speed from the relative speed by using the information on the vehicle speed and the information on the steering angle or the turning angle. In this way, the control section  51  calculates the absolute speed of the detected object. In the case where such an absolute speed is equal to or lower than a threshold value (for example, 0.5 km/h) that is set to zero or a lowest value as possible, the control section  51  determines that the detected object is a static object that exists on/above the ground. 
     The control section  51  compares each of the plural detection points of the object detected by the radar sensor  20  with the information on the three-dimensional data of the object identified on the map data  70 , so as to calculate the error therebetween. In the case where the calculated error is equal to or larger than a specified value, the control section  51  may determine that the radar sensor  20  is abnormal. In the case where the control section  51  determines that the error is equal to or larger than the specified value not only in the single determination result but for plural times set in advance, the control section  51  may determine that the radar sensor  20  is abnormal. 
     &lt;2. Operation Example of Abnormality Diagnosis System&gt; 
     A description will hereinafter be made on an operation example of the abnormality diagnosis system  50  according to this embodiment. 
     (3.1. Flowchart) 
       FIG. 2  is a flowchart of an example of processing executed by the abnormality diagnosis system  50 . The processing executed by the abnormality diagnosis system  50  is executed in cooperation between the control section  51  and various programs stored in the storage device  55 . 
     First, the control section  51  in the abnormality diagnosis system  50  stores the map data  70  in the storage device  55  by using the data that is transmitted from the map data generator  1  on the outside of the vehicle (step S 11 ). In the case where the map data  70  has already been stored in the storage device  55 , the map data  70  is updated by using the data transmitted from the map data generator  1 . 
     Next, the control section  51  identifies the position of the vehicle on the map data  70  (step S 13 ). More specifically, the control section  51  identifies the GPS position of the vehicle on the basis of the GPS signal received by the GPS receiver  59 , and determines the position of the vehicle on the map data  70 . As described above, the control section  51  may determine the position of the vehicle on the map data  70  by setting the specified error. 
     Next, the control section  51  identifies, on the map data  70 , a candidate for the object that exists around the determined position of the vehicle (step S 15 ). For example, the control section  51  may identify the candidate for the object to be detected by the detector according to a type of the detector as a diagnosis target, a detection direction from the vehicle, or the like. 
     Next, the control section  51  identifies the object detected by the radar sensor  20  on the basis of the detection signal obtained from the radar sensor  20  (step S 17 ). For example, the control section  51  may identify the object detected by the radar sensor  20  according to an example illustrated in  FIG. 3 . The identification of the object described herein includes such identification that the object is not detected by the radar sensor  20 . 
     First, the control section  51  determines whether any type of the object is detected by the radar sensor  20  (step S 31 ). If the object is not detected by the radar sensor  20  (S 31 /n), the control section  51  determines that the static object is not detected (step S 39 ). On the other hand, if the object is detected by the radar sensor  20  (S 31 /y), the control section  51  determines the absolute speed of the object detected by the radar sensor  20  (step S 33 ). For example, the control section  51  may calculate the relative speed between the object and the vehicle by dividing a change in a distance between the detected object and the vehicle by time and subtract the vehicle speed from the relative speed, so as to determine the absolute speed of the object. 
     Next, the control section  51  determines whether the determined absolute speed is zero or equal to or lower than the threshold value (for example, 0.5 km/h), which is set in advance (step S 35 ). If determining that the absolute speed of the object detected by the radar sensor  20  is not zero or exceeds the threshold value, which is set in advance, (S 35 /n), the control section  51  determines that the static object is not detected (step S 39 ). On the other hand, if the determined absolute speed is zero or is equal to or lower than the threshold value, which is set in advance, (S 35 /y), the control section  51  determines that the static object is detected (step S 37 ). 
     Returning to  FIG. 2 , in step S 17 , after identifying the object detected by the radar sensor  20 , the control section  51  determines the presence or the absence of the abnormality of the radar sensor  20  by comparing the detection data obtained by the radar sensor  20  with the three-dimensional data on the object contained in the map data  70  (step S 19 ). 
       FIG. 4  illustrates an example of processing for determining the presence or the absence of the abnormality of the radar sensor  20 . First, the control section  51  determines whether the static object is detected by the radar sensor  20  (step S 41 ). If the static object is not detected (S 41 /n), the control section  51  determines whether the object exists in an area around the vehicle, which is identified in step S 15 , on the map data  70  (step S 53 ). If the object exists around the vehicle on the map data  70  (S 53 /y), the control section  51  determines that the radar sensor  20  is abnormal (step S 51 ). On the other hand, if the object does not exist around the vehicle on the map data  70  (S 53 /n), the control section  51  determines that the radar sensor  20  is not abnormal (step S 49 ). 
     If the static object is detected by the radar sensor  20  in step S 41  (S 41 /y), the control section  51  identifies the object on the map data  70  that corresponds to the detected object (step S 43 ). For example, the control section  51  may identify the object on the map data  70  that corresponds to the detected object on the basis of a relative position of the object detected by the radar sensor  20  to the position of the vehicle or on the basis of the distance from the vehicle to the detected object. 
     Next, the control section  51  compares each of the plural detection points of the static object detected by the radar sensor  20  with the information on the three-dimensional data of the object identified on the map data  70 , so as to calculate the error therebetween (step S 45 ). For example, the control section  51  may calculate displacement of each of the detection points that are identified on the basis of the GPS position of the vehicle with respect to the three-dimensional data of the object on the map data  70 , the distance from the vehicle to each of the detection points by the radar sensor  20 , a direction of the vehicle with respect to each of the detection points by the radar sensor  20 , and the like. 
     Next, the control section  51  determines whether the calculated error is equal to or smaller than a threshold value, which is set in advance, (step S 47 ). If the calculated error is smaller than the threshold value (S 47 /y), the control section  51  determines that the radar sensor  20  is not abnormal (step S 49 ). On the other hand, if the calculated error is equal to or larger than the threshold value (S 47 /n), the control section  51  determines that the radar sensor  20  is abnormal (step S 51 ). 
     As an example,  FIG. 5  illustrates a field of view from the vehicle at certain time. In  FIG. 5 , a lane  71 , a land bridge  73 , and a traffic sign  75  are included in the field of view.  FIG. 6  illustrates the map data  70  that corresponds to this field of view. On the map data  70 , an area X that can be detected by the radar sensor  20  is indicated. 
     In the case where the radar sensor  20  is not abnormal and the vehicle reaches a position where the radar sensor  20  possibly detects the traffic sign  75  during travel on the lane  71 , the radar sensor  20  obtains the detection data that corresponds to the traffic sign  75 . On the other hand, in the case where the radar sensor  20  is abnormal and the vehicle reaches the position where the radar sensor  20  possibly detects the traffic sign  75  during the travel on the lane  71 , the radar sensor  20  does not obtains the detection data that corresponds to the traffic sign  75 , or the error between the detection point and the actual position of the traffic sign is increased. Thus, the control section  51  can determine the abnormality of the radar sensor  20 . 
     The control section  51  may compare the detection data that is obtained by the radar sensor  20  with detection data obtained by another detector mounted to the vehicle in addition to the map data  70 , so as to improve reliability of a diagnosis result. Examples of such other detector are an imaging sensor, a Lidar unit, and an ultrasonic sensor. For example, as a result of the comparison of the detection data obtained by the radar sensor  20  with the map data  70  and the comparison thereof with the detection data obtained by the other detector, the control section  51  determines that all the detection data obtained by the radar sensor  20  is abnormal. In such a case, the control section  51  may confirm such a diagnosis result that the radar sensor  20  is abnormal. 
     As it has been described so far, the abnormality diagnosis system  50  according to this embodiment compares the map data  70 , which contains the three-dimensional data on the objects existing on/above the ground, with the detection data obtained by the radar sensor  20 , so as to diagnose the presence or the absence of the abnormality of the radar sensor  20 . Therefore, by determining whether the radar sensor  20  obtains the detection data on the actually-existing object, it is possible to improve the reliability of the abnormality diagnosis result by the radar sensor  20 . 
     In addition, the map data  70 , which is compared with the detection data obtained by the radar sensor  20 , is updated by using the data transmitted from the map data generator  1 . Therefore, the highly-reliable map data  70  is used, and the reliability of the diagnosis result can be improved. 
     The preferred embodiment of the present invention has been described in detail so far with reference to the accompanying drawings. However, the present invention is not limited to such an embodiment. It is obvious that a person who has basic knowledge in the technical field to which the present invention pertains could have easily arrived at various modification examples and application examples that fall within the scope of the technical idea described in the claims. It is understood that those naturally fall within the technical scope of the present invention. 
     For example, in the above embodiment, the description has been made on the example in which the radar sensor  20  is used as the detector to be the diagnosis target. However, the detector is not limited to the radar sensor  20 . The detector as the diagnosis target may be any of various sensors, such as the imaging sensor, the Lidar unit, and the ultrasonic sensor, detecting the surrounding environment of the vehicle. 
     In the above embodiment, the description has been made on the example in which the GPS receiver  59  is provided as the positioning device. However, the present invention is not limited to such an example. The positioning device is not limited to the GPS receiver  59  as long as the positioning device is a device capable of positioning the vehicle on the earth. For example, the positioning device may be a device that positions a current location of the vehicle on the basis of the surrounding environment detected by an on-board sensor such as the radar sensor  20  while referring to the data on the surrounding environment accumulated in the map data generator. 
     REFERENCE SIGNS LIST 
     
         
         
           
               1 : Map data generator 
               20 : Radar sensor 
               50 : Abnormality diagnosis system 
               51 : Control section 
               55 : Storage device 
               59 : GPS receiver 
               61 : Network communication module 
               70 : Map data