Patent Publication Number: US-2023143224-A1

Title: Apparatus and method for controlling a vehicle

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application claims the benefit of and priority to Korean Patent Application No. 10-2021-0151749, filed in the Korean Intellectual Property Office on Nov. 5, 2021, the entire contents of which are incorporated herein by reference. 
     TECHNICAL FIELD 
     The present disclosure relates to an apparatus and method for controlling a vehicle, and more particularly, relates to a technology for controlling an autonomous vehicle in real time. 
     BACKGROUND 
     The statements in this section merely provide background information related to the present disclosure and may not constitute prior art. 
     Recently, an autonomous vehicle and a technology for allowing the autonomous vehicle to travel along a path have been developed. To control the autonomous vehicle to travel along a desired path, a vehicle control apparatus may follow the desired path as a travel path. 
     SUMMARY 
     In the case where the autonomous vehicle follows a travel path using a conventional method, the autonomous vehicle may fail to track a travel lane when the travel path is blocked by a vehicle parked or stopped on a shoulder, a vehicle trailing at an intersection, or a vehicle stopping across a line while changing a lane. Furthermore, in the case where the autonomous vehicle follows the travel path through the conventional method, it may be difficult to change a lane in a situation in which there is no available lane in the vicinity or to respond to a situation while driving on a lane so as to be biased to one side. 
     The present disclosure has been made to solve the above-mentioned problems occurring in the prior art while advantages achieved by the prior art are maintained intact. 
     An aspect of the present disclosure provides a technology for controlling an autonomous vehicle to travel using a bypass path when a travel path of the autonomous vehicle is blocked. 
     Another aspect of the present disclosure provides a technology for setting a plurality of bypass paths and selecting one of the plurality of bypass paths in real time. 
     The technical problems to be solved by the present disclosure are not limited to the aforementioned problems, and any other technical problems not mentioned herein should be clearly understood from the following description by those having ordinary skill in the art to which the present disclosure pertains. 
     According to an aspect of the present disclosure, an apparatus for controlling a vehicle includes: a memory, a network interface, and a processor. The processor determines whether the vehicle is in a bypass situation in which the vehicle has to bypass, calculates a plurality of bypass paths capable of replacing a previously set travel path in the bypass situation, evaluates the plurality of bypass paths, selects one bypass path, based on an evaluation result of the plurality of bypass paths, and performs control on the vehicle such that the vehicle travels while following the selected one bypass path. 
     In an embodiment, the processor may determine whether the vehicle is in the bypass situation, based on a traffic flow impediment target and ambient information included in integrated object information. 
     In an embodiment, the processor may determine whether the vehicle is in the bypass situation, based on a presence of a target impeding a traffic flow on the travel path of the vehicle and a possibility to respond to the target by deflection on a line or a lane change. 
     In an embodiment, the processor may determine, as the bypass situation, a situation where the travel path is blocked by another vehicle parked or stopped on a shoulder, another vehicle trailing at an intersection, or another vehicle stopping across a line while making a lane change. 
     In an embodiment, when a traffic flow impediment target exists, the processor may determine whether to perform waiting and speed reduction for the target or whether to calculate the plurality of bypass paths and travel along an alternative path. 
     In an embodiment, when it is impossible to respond to the bypass situation by deflection of the vehicle on a line or a lane change of the vehicle in the bypass situation, the processor may calculate a loss function through waiting time for existing path tracking and sampling, and when an output value of the loss function is greater than a threshold value, the vehicle may follow an alternative path. 
     In an embodiment, the processor may calculate expected waiting time for calculating the loss function. When an existing path is followed or at an intersection, the expected waiting time may be a time period to the next signal, and wherein when a traffic flow impediment target exists, the expected waiting time may be an expected time period until the traffic flow impediment target travels again. 
     In an embodiment, when a preference criterion for selecting the one bypass path among the plurality of bypass paths is set to include safety of the vehicle during travel, the processor may select, among the plurality of bypass paths, bypass paths along which a distance between the vehicle and another vehicle is greater than or equal to a threshold value, and determine a final bypass path, among the selected bypass paths, along which the sum of distances between the vehicle and the another vehicle is maximum. 
     In an embodiment, the processor may calculate an expected path of another vehicle and an expected path of the vehicle for each time, may calculate an expected relative distance between the vehicle and another vehicle for each time, and may exclude a corresponding path from candidate bypass paths when the expected relative distance is shorter than a minimum threshold value at arbitrary time. 
     In an embodiment, the processor may generate a first bypass path and set the first bypass path as a new reference path when a reference path of the vehicle is impeded by another vehicle and may generate a modified bypass path when the vehicle is impeded by another vehicle while travelling along the new reference path corresponding to the first bypass path. 
     In an embodiment, the processor may collect a plurality of traces of a plurality preceding vehicles travelling ahead of the vehicle and may calculate the plurality of bypass paths by tracking the plurality of preceding vehicles during a plurality of frames and determining whether the plurality of preceding vehicles consistently precede the vehicle. 
     In an embodiment, the processor may calculate a risk based loss value, a detour distance based loss value, and a preceding vehicle trace based loss value while generating a loss function, may convert a loss value into a score by using the loss function, and may determine a final bypass path based on a risk score, a detour distance score, and a preceding vehicle trace score calculated while the loss function is generated. 
     In an embodiment, the processor may assign weighting values to the risk score, the detour distance score, and the preceding vehicle trace score of each of the plurality of bypass paths, may calculate a weighted average score of each of the plurality of bypass paths by using the scores to which the weighting values are assigned, may compare the weighted average scores of the plurality of bypass paths, and may select a path having the highest weighted average score as the final bypass path. 
     In an embodiment, the processor may compare a loss value of an alternative path and a loss value of a newly generated alternative path in the evaluation and may modify the bypass path to the newly generated alternative path when the loss value of the existing alternative path is greater than the loss value of the newly generated alternative path. 
     In an embodiment, the processor may determine whether to end a bypass section, depending on whether the vehicle deviates from a lane link set and a road link section belonging to a start point and an end point of the bypass path and whether the vehicle follows an existing global path. 
     According to another aspect of the present disclosure, a method for controlling a vehicle includes determining whether the vehicle is in a bypass situation in which the vehicle has to bypass, calculating a plurality of bypass paths capable of replacing a previously set travel path in the bypass situation, evaluating the plurality of bypass paths, selecting one bypass path, based on an evaluation result of the plurality of bypass paths, and controlling the vehicle to travel along the selected one bypass path. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The above and other objects, features and advantages of the present disclosure should be more apparent from the following detailed description taken in conjunction with the accompanying drawings: 
         FIGS.  1 A,  1 B and  1 C  are views illustrating various situations to which a vehicle control method according to an embodiment of the present disclosure is applied; 
         FIG.  2    is a view illustrating a vehicle control apparatus according to an embodiment of the present disclosure; 
         FIG.  3    is a view illustrating a situation in which a bypass path is required during travel of a vehicle according to an embodiment of the present disclosure; 
         FIG.  4    is a flowchart illustrating a method of controlling a vehicle such that the vehicle travels along a bypass path according to an embodiment of the present disclosure; 
         FIG.  5    is a view illustrating a finite state machine (FSM) illustrating a driving state of following a bypass path according to an embodiment of the present disclosure; 
         FIG.  6    is a flowchart illustrating a method of controlling a vehicle such that the vehicle travels along a bypass path according to an embodiment of the present disclosure; 
         FIG.  7    is a view illustrating methods of generating a plurality of bypass paths according to an embodiment of the present disclosure; 
         FIG.  8    is a view illustrating a method of determining a risk level in consideration of an expected path and collision time according to an embodiment of the present disclosure; 
         FIG.  9    is a view illustrating generation of a bypass path and modification of the bypass path according to an embodiment of the present disclosure; 
         FIG.  10    is a view illustrating a method of comparing the similarity between trace sets of a plurality of bypass paths according to an embodiment of the present disclosure; 
         FIG.  11    is a flowchart illustrating a method of determining a final path among a plurality of bypass paths according to an embodiment of the present disclosure; 
         FIG.  12    is a view illustrating a method of determining a final path among a plurality of bypass paths according to an embodiment of the present disclosure; 
         FIG.  13    is a flowchart illustrating a method of evaluating a bypass path according to an embodiment of the present disclosure; 
         FIG.  14    is a flowchart illustrating a determination method of releasing a bypass situation according to an embodiment of the present disclosure; and 
         FIG.  15    illustrates a computing system according to an embodiment of the present disclosure. 
     
    
    
     The drawings described herein are for illustration purposes only and are not intended to limit the scope of the present disclosure in any way. 
     DETAILED DESCRIPTION 
     Hereinafter, some embodiments of the present disclosure are described in detail with reference to the exemplary drawings. In adding the reference numerals to the components of each drawing, it should be noted that the identical or equivalent component is designated by the identical numeral even when they are displayed on other drawings. Further, in describing the embodiment of the present disclosure, a detailed description of well-known features or functions is ruled out in order not to unnecessarily obscure the gist of the present disclosure. 
     In describing the components of the embodiment according to the present disclosure, terms such as first, second, “A”, “B”, (a), (b), and the like may be used. These terms are merely intended to distinguish one component from another component, and the terms do not limit the nature, sequence or order of the components. Unless otherwise defined, all terms used herein, including technical or scientific terms, have the same meanings as those generally understood by those having ordinary skill in the art to which the present disclosure pertains. Such terms as those defined in a generally used dictionary are to be interpreted as having meanings equal to the contextual meanings in the relevant field of art, and are not to be interpreted as having ideal or excessively formal meanings unless clearly defined as having such in the present application. 
     When a component, device, element, or the like of the present disclosure is described as having a purpose or performing an operation, function, or the like, the component, device, or element should be considered herein as being “configured to” meet that purpose or to perform that operation or function. 
     Hereinafter, embodiments of the present disclosure are described in detail with reference to  FIGS.  1  to  14   . 
       FIGS.  1 A,  1 B,  1 C  are views illustrating various situations to which a vehicle control method according to an embodiment of the present disclosure is applied. 
     Referring to  FIG.  1 A , a vehicle control apparatus may be configured such that a vehicle  111  travels along a travel path  112  and makes a right turn so as to be adjacent to the shoulder of a road while following the travel path  112 . When there is another vehicle  113  parked or stopped on the shoulder adjacent to the travel path  112 , the vehicle control apparatus may control the vehicle  111  such that the vehicle  111  travels along a bypass path  114  that bypasses the other vehicle  113 . 
     Referring to  FIG.  1 B , the vehicle control apparatus may be configured such that a vehicle  121  travels along a travel path  122  and makes a left turn at an intersection while following the travel path  122 . When there is another vehicle  123  that is trailing at the intersection on the travel path  122  and thus obstructs the passage of the vehicle  121  along the travel path  122 , the vehicle control apparatus may control the vehicle  121  such that the vehicle  121  travels along a bypass path  124  that bypasses the other vehicle  123 . 
     Referring to  FIG.  1 C , the vehicle control apparatus may be configured such that a vehicle  131  travels while following a travel path  132  passing through the last lane adjacent to the shoulder of a road. When there is another vehicle  133  parked or stopped on the shoulder adjacent to the travel path  132 , the vehicle control apparatus may control the vehicle  131  such that the vehicle  131  travels along a bypass path  134  that bypasses the other vehicle  133 . 
     The vehicle control apparatus may be configured such that a vehicle  141  travels while following a travel path  142  along which the vehicle  141  travels straight ahead on a specified lane. When there is another vehicle  143  that stops across a line while making a lane change in front of the travel path  142 , the vehicle control apparatus may control the vehicle  141  such that the vehicle  141  travels along a bypass path  144  that bypasses the other vehicle  143 . 
     The vehicle control apparatus according to an embodiment of the present disclosure may control a vehicle such that the vehicle travels along a bypass path, by determining an optimum bypass path among a plurality of bypass paths based on a risk level in a drivable area around a travel path, a detour distance of a bypass path, and a preceding vehicle path and calculating a travel strategy through a selection of intersection of another vehicle on the bypass path, cut-in of another vehicle, in-pass of another vehicle, or another vehicle that is deflected. 
       FIG.  2    is a view illustrating a vehicle control apparatus according to an embodiment of the present disclosure. 
     The vehicle control apparatus  200  may establish a bypass path of a vehicle on a general road including a straight path and various curved paths and may control the vehicle to respond to intersection, cut-in, in-pass, and deflection of another vehicle. The vehicle control apparatus  200  may include a cognitive sensor  201 , a high-definition map transmission module  205 , V2X  206 , a CAN  207 , a GPS  208 , a traffic flow impediment target selection module  209 , a location awareness module  210 , a road information convergence module  215 , an object fusion module  220 , a bypass situation determination module  225 , a multi-path based bypass path calculation module  230 , a bypass path evaluation module  235 , a bypass situation release determination module  240 , a control tracking path output module  245 , a speed profile output module  250 , and a control parameter output module  255 . 
     The cognitive sensor  201  may include a LIDAR  202 , a camera  203 , and a radar  204 . Cognitive information through the LIDAR  202 , the camera  203 , and the radar  204  may provide reliable information for each object through the object fusion module  220 . 
     The high-definition map transmission module  205  may generate a high-definition map for an area around the vehicle. The V2X  206  may transmit and receive information required for autonomous driving with another vehicle through vehicle to everything communication. The vehicle control apparatus may perform communication with other devices in the vehicle through the CAN  207 . The GPS  208  may generate location information of the vehicle. The traffic flow impediment target selection module  209  may sense an object that blocks a travel path of the vehicle. The traffic flow impediment target selection module  209  may transfer a traffic flow impediment target to the bypass situation determination module  225 . 
     The location awareness module  210  may receive cognitive information from the cognitive sensor  201 . The location awareness module  210  may receive location information of the vehicle from the GPS  208 . The location awareness module  210  may receive high-definition map information from the high-definition map transmission module  205 . The location awareness module  210  may compare the cognitive information, the location information of the vehicle, and the high-definition map information and may output the location information of the vehicle and location awareness reliability information. The location awareness module  210  may transfer, to the road information convergence module  215 , the accurate location of the host vehicle that is a vehicle controlled by the vehicle control apparatus itself. 
     The road information convergence module  215  may use the cognitive information and the high-definition map information to generate high-definition map information around the vehicle. The road information convergence module  215  may output, to the object fusion module  220 , an accurate map around the host vehicle. 
     The object fusion module  220  may output an object on the accurate map through the cognitive information and the high-definition map information around the host vehicle. The object fusion module  220  may transfer integrated object information to the bypass situation determination module  225 . 
     The bypass situation determination module  225  may determine whether the vehicle is in a bypass situation in which the vehicle has to bypass. The bypass situation determination module  225  may determine whether the vehicle is in the bypass situation, by using the traffic flow impediment target and ambient information included in the integrated object information. The bypass situation determination module  225  may transfer bypass situation information to the multi-path based bypass path calculation module  230 . 
     The multi-path based bypass path calculation module  230  may calculate a plurality of bypass paths capable of replacing the previously set travel path in the bypass situation. The multi-path based bypass path calculation module  230  may transfer the plurality of bypass paths to the bypass path evaluation module  235 . 
     The bypass path evaluation module  235  may evaluate the plurality of bypass paths. The bypass path evaluation module  235  may evaluate the plurality of bypass paths using risk levels of the plurality of bypass paths, detour distances of the plurality of bypass paths, and paths of a preceding vehicle. The bypass path evaluation module  235  may transfer bypass path evaluation information to the bypass situation release determination module  240 . 
     The bypass situation release determination module  240  may determine whether the area where the vehicle travels at present is within a bypass section. The bypass situation release determination module  240  may switch to a general travel path in response to determination that the bypass situation is released. The bypass situation release determination module  240  may transfer the bypass path or the general travel path to the control tracking path output module  245 . 
     The control tracking path output module  245  may calculate a control tracking path of the vehicle based on the bypass path in the bypass situation. When the bypass situation is released, the control tracking path output module  245  may calculate the control tracking path of the vehicle, based on the general travel path. The control tracking path output module  245  may transfer the control tracking path to the speed profile output module  250 . 
     The speed profile output module  250  may output a speed profile of the vehicle through information such as the curvature of the control tracking path, the gradient of the control tracking path, the speed limit of the control tracking path, and a preceding vehicle on the control tracking path. The speed profile output module  250  may transfer the speed profile and the control tracking path to the control parameter output module  255 . 
     The control parameter output module  255  may calculate a controller input parameter, based on the speed profile and the control tracking path. The vehicle control apparatus  200  may control the vehicle to travel along a path set by calculating the controller input parameter. 
       FIG.  3    is a view illustrating a situation in which a bypass path is required during travel of a vehicle according to an embodiment of the present disclosure. 
     The vehicle control apparatus may control a vehicle  151  such that the vehicle  151  travels along a specified travel path  152 . Various situations may occur during autonomous driving of the vehicle  151 . For example, another vehicle  153  may be located in front of the travel path  152 . In another example, when the vehicle  151  crosses a railroad, a stop signal at the crossroads, an intersection with signals, a T-shaped intersection, a merge section, a highway, or a driving situation in a low-visibility environment may occur. In another example, a long-distance driving situation may occur due to changes in various driving environments. When the various situations occur, the vehicle control apparatus may determine whether a bypass path  154  is required. When the bypass path  154  is required, the vehicle control apparatus may control the vehicle  151  such that the vehicle  151  travels along the bypass path  154 . 
     Hereinafter, it is assumed that the vehicle control apparatus performs the processes of  FIGS.  4  to  6 ,  11 ,  13 , and  14   . Furthermore, in the descriptions of  FIGS.  4  to  6 ,  11 ,  13 , and  14   , operations described as being performed by the vehicle control apparatus may be understood as being controlled by a processor of the vehicle control apparatus (e.g., a processor  1100  of  FIG.  15   ). 
       FIG.  4    is a flowchart illustrating a method of controlling a vehicle such that the vehicle travels along a bypass path according to an embodiment of the present disclosure. 
     In operation  301 , the vehicle control apparatus may derive an integrated lane. In operation  301 , the vehicle control apparatus may select a travel lane for which a travel path is to be set. In operation  303 , the vehicle control apparatus may use five sub-modules. The five sub-modules may include the LIDAR  202 , the camera  203 , the radar  204 , the high-definition map transmission module  205 , and the GPS  208 . In operation  303 , the vehicle control apparatus may recognize surroundings using the five sub-modules. In operation  305 , the vehicle control apparatus may select a final traffic flow impediment target. In operation  305 , the vehicle control apparatus may receive final traffic flow impediment target select information from an interest target determination system for real-time bypass path driving of an autonomous vehicle. 
     In operation  307 , the vehicle control apparatus may determine whether the vehicle is in a bypass situation in which the vehicle has to bypass. In operation  307 , the vehicle control apparatus may determine whether the vehicle is in the bypass situation in which the vehicle has to bypass, based on a presence of a target impeding a traffic flow on the travel path of the vehicle and a possibility to respond to the target by deflection on a line or a lane change. 
     In operation  309 , the vehicle control apparatus may calculate a multi-path based bypass path. In operation  309 , the vehicle control apparatus may calculate a plurality of bypass paths capable of replacing the previously set travel path in the bypass situation. In operation  309 , the vehicle control apparatus may determine that the vehicle is in the bypass situation and may calculate a plurality of travel paths along which the vehicle is able to bypass in the bypass situation. 
     In operation  311 , the vehicle control apparatus may evaluate the plurality of bypass paths. In operation  311 , the vehicle control apparatus may analyze risk levels of the plurality of bypass paths, detour distances of the plurality of bypass paths, and a path of a preceding vehicle. Based on the analysis result, the vehicle control apparatus may select one of the plurality of bypass paths as an optimum path along which the vehicle bypasses. 
     In operation  313 , the vehicle control apparatus may perform bypass path tracking control. In operation  313 , the vehicle control apparatus may select one bypass path based on the evaluation of the plurality of bypass paths. In operation  313 , the vehicle control apparatus may perform control on the vehicle such that the vehicle travels while following the selected one bypass path. 
     In operation  315 , the vehicle control apparatus may evaluate a bypass path. The vehicle control apparatus may consistently perform bypass path evaluation on the control path along which the vehicle travels at present. When the bypass path evaluation result recommends the existing path, the vehicle control apparatus may proceed to operation  317 . When the bypass path evaluation result recommends a new bypass path, the vehicle control apparatus may proceed to operation  321 . 
     In operation  317 , the vehicle control apparatus may determine whether the bypass situation is released. In operation  317 , the vehicle control apparatus may track whether the current bypass situation is released. When the tracking result shows that the bypass situation is released, the vehicle control apparatus may proceed to operation  319 . When the tracking result shows that the bypass situation is not released, the vehicle control apparatus may proceed to operation  313 . 
     In operation  319 , the vehicle control apparatus may control the vehicle in general driving. The general driving may include host-vehicle lane tracking driving. When the bypass situation is released, the vehicle control apparatus may switch to the general driving and may control the vehicle. 
     In operation  321 , the vehicle control apparatus may modify the bypass path. When the bypass path evaluation result is a new path, the vehicle control apparatus may change the current control path to the new bypass path. After modifying the bypass path to the new bypass path in operation  321 , the vehicle control apparatus may return to operation  311  to perform bypass path evaluation on the new bypass path. 
       FIG.  5    is a view illustrating a finite state machine (FSM) illustrating a driving state of following a bypass path according to an embodiment of the present disclosure. 
     A driving state of following a bypass path may include a general driving state  330 , a bypass determination state  340 , and a bypass state  350 . The general driving state  330  may define a general driving state before bypass driving. 
     When a bypass target exists on a vehicle travel path, a transition from the general driving state  330  to the bypass determination state  340  may be made. In the bypass determination state  340 , whether the front bypass target is a target that a vehicle unilaterally has to avoid and whether it is impossible to respond to the target due to a lane change or deflection of the vehicle on a line may be observed together with bypass path evaluation during specified N frames. 
     When it is determined that the vehicle has to bypass, a bypass situation may be confirmed, and a transition from the bypass determination state  340  to the bypass state  350  may be made. When it is determined that the vehicle does not have to bypass, a transition from the bypass determination state  340  to the general driving state  330  may be made. 
     In the bypass state  350 , bypass path control tracking may be performed. In the bypass state  350 , the current bypass path may be consistently evaluated and modified and may be observed until the bypass situation is released. 
     In the bypass state  350 , whether to release the bypass situation may be determined. Whether to release the bypass situation may be determined based on whether the vehicle deviates from a lane link set and a road link section belonging to the start point and the end point of the bypass path and whether the vehicle follows the existing global path. When the vehicle deviates from the end point of the bypass path and follows the existing global path, a transition from the bypass state  350  to the general driving state  330  may be made. When the vehicle deviates from the end point of the bypass path, but fails to enter the existing global path due to other objects, the bypass state  350  of performing bypass driving before entrance to the global path while consistently modifying the bypass path may be maintained. 
     When the vehicle does not deviate from the end point of the bypass path, but converges to the existing global path, a transition from the bypass state  350  to the general driving state  330  may be made during bypass in the next frame because an end point of a new bypass path is naturally determined to be a path that more rapidly converges to the existing global path and the detour distance is decreased, compared to the existing path. 
       FIG.  6    is a flowchart illustrating a method of controlling a vehicle such that the vehicle travels along a bypass path according to an embodiment of the present disclosure. 
     In operation  351 , the vehicle control apparatus may enter a bypass situation. In operation  351 , the vehicle control apparatus may set a real-time bypass path based driving system of an autonomous vehicle. 
     In operation  353 , the vehicle control apparatus may determine whether it is possible to respond by deflection of the vehicle on a line or a lane change of the vehicle. In operation  353 , the vehicle control apparatus may determine whether it is possible to respond to the situation by a method of deflecting the vehicle to one side on the line, changing the travel lane of the vehicle, or reducing the speed of the vehicle. When a traffic flow impediment target exists, the vehicle control apparatus may determine whether to perform waiting and speed reduction for the target or whether to calculate a bypass path and travel along an alternative path. The vehicle control apparatus may proceed to operation  355  when it is possible to respond (operation  353 —YES). The vehicle control apparatus may proceed to operation  357  when it is impossible to respond (operation  353 —NO). 
     In operation  355 , the vehicle control apparatus may follow the existing path. The vehicle control apparatus may follow the existing path while responding to the situation by the method of deflecting the vehicle to one side on the line, changing the travel lane of the vehicle, or reducing the speed of the vehicle. 
     In operation  357 , the vehicle control apparatus may calculate a loss function. 
     In detailed operation  359  included in operation  357 , the vehicle control apparatus may calculate expected waiting time. The expected waiting time may be time to the next signal when the existing path is followed or at an intersection. When a traffic flow impediment target exists, the expected waiting time may be expected time until the traffic flow impediment target travels again. 
     In detailed operation  361  included in operation  357 , the vehicle control apparatus may identify the consistency of various samples. When the vehicle control apparatus considers only the current situation for a traffic flow impediment target, a tendency of surrounding circumstances to change may not be reflected in the driving strategy of the vehicle control apparatus. For example, another vehicle that is waiting to make a U-turn may remain stopped and may travel again when the host vehicle yields to the other vehicle, or another vehicle that is trailing may travel again due to release of a front situation. Accordingly, when the corresponding situation between the various samples is not solved, travel to a bypass path may be determined. The vehicle control apparatus may determine the consistency between the various samples to increase the reliability for the determination result. 
     In operation  363 , the vehicle control apparatus may determine whether an output value of the loss function is greater than a threshold value. When it is impossible to respond to the situation by deflection of the vehicle or a lane change, the vehicle control apparatus may calculate the loss function through waiting time for the existing path tracking and sampling. A loss value proportional to the expected waiting time may have a real value. When a plurality of samples are consistent with one another, a loss value having a magnitude proportional to a sampling value may be obtained. The weighted average of loss values may be an output value of the final loss function. Weighting values may be tuning parameters. 
     The vehicle control apparatus may proceed to operation  365  when the output value of the loss function is greater than the threshold value (operation  363 —Yes). The vehicle control apparatus may proceed to operation  355  when the output value of the loss function is less than or equal to the threshold value (operation  363 —No). 
     In operation  365 , the vehicle control apparatus may follow an alternative path. The vehicle control apparatus may follow the alternative path when the output value of the loss function exceeds the threshold value. The vehicle control apparatus may bypass along the alternative path when the output value of the loss function is higher than the threshold value. When the output value of the loss function is higher than the threshold value, the vehicle control apparatus may follow the bypass path because a loss for the existing path is greater than that when the vehicle control apparatus follows the bypass path. When the output value of the loss function is less than or equal to the threshold value, the vehicle control apparatus may determine that it is more preferable to wait until the situation is resolved after coming to a stop while following the existing path. 
       FIG.  7    is a view illustrating methods of generating a plurality of bypass paths according to an embodiment of the present disclosure. 
     In situation  370 , the vehicle control apparatus may generate a plurality of paths in a drivable area. The vehicle control apparatus may output all drivable paths serving as bypass paths in the entire drivable area. The load of the vehicle control apparatus generating a travel path may be small, and the computational load required for verifying the situation compatibility of the corresponding paths may be large. For example, loads required for determining a risk level for each path and comparing a target path and a preceding vehicle path may be large. 
     In situation  380 , the vehicle control apparatus may generate a plurality of paths based on an fRRT algorithm. In situation  390 , the vehicle control apparatus may generate a plurality of paths based on an RRT algorithm. The vehicle control apparatus may use the RRT or fRRT method based on random probability to generate as many random paths as possible. 
     As the interval between the paths generated by the vehicle control apparatus is decreased, the number of paths generated may be increased. As the interval between the paths generated by the vehicle control apparatus is decreased, the amount of computation finally performed for path verification may be increased. The vehicle control apparatus may tune the number of generated paths depending on the computation performance of a system. 
     The multi-path generation method is not limited to the RRT or fRRT method, and other path generation algorithms may be used to generate a plurality of paths. For example, a method of generating a plurality of different paths by repeatedly performing a process of taking a path through control points on a grid may be used. In another example, a method of generating a plurality of paths while varying offset around a representative path may be used. 
       FIG.  8    is a view illustrating a method of determining a risk level in consideration of an expected path and collision time according to an embodiment of the present disclosure. 
     The vehicle control apparatus may calculate one bypass path by analyzing a plurality of paths. The most preferred path among the plurality of paths generated according to the method described with reference to  FIG.  7    may be determined to be the one bypass path. 
     Referring to  FIG.  8   , when the preference criterion for determining the one bypass path is set to safety of the host vehicle during travel, among the paths along which the distance between the host vehicle and another vehicle is greater than or equal to a threshold value, a path along which the sum of the distances between the host vehicle and the other vehicle is maximum may be set to be the one bypass path. However, without being limited thereto, the preference criterion may be changed or complemented by another method of ensuring driving stability, riding quality, or smoothness of driving. 
     An expected path of the other vehicle and an expected path of the host vehicle calculated by the vehicle control apparatus may include location information of an object for each time. The vehicle control apparatus may calculate the expected relative distance d points  (t) between the host vehicle and the other vehicle for each time by using the expected path of the other vehicle and the expected path of the host vehicle. 
     When the distance between the host vehicle and the other vehicle at arbitrary time t is shorter than a minimum threshold value Min_T, the vehicle control apparatus may determine that the distance between the host vehicle and the other vehicle is very short enough to cause actual collision. The minimum threshold value Min_T may be minimum time during which the host vehicle is able to respond to prevent collision. When the distance between the host vehicle and the other vehicle is shorter than the minimum threshold value Min_T, the corresponding path may cause a high risk, and therefore the vehicle control apparatus may exclude the corresponding path from candidate bypass paths. 
     When the interval between the host vehicle and the other vehicle for each time is consistently increased, the vehicle control apparatus may determine the path as a safe path. To determine whether the interval between the host vehicle and the other vehicle for each time is consistently increased, the vehicle control apparatus may select a situation in which the interval between the host vehicle and the other vehicle is determined to be longer, by using values having meaningful statistical significance, such as the sum of the distances between the host vehicle and the other vehicle for each time, the average of the distances between the host vehicle and the other vehicle, the minimum of the distances between the host vehicle and the other vehicle, or the median of the distances between the host vehicle and the other vehicle. 
     The vehicle control apparatus may determine more accurate collision possibility with an increase in the accuracy of the expected paths. The vehicle control apparatus may assign a risk judgment score in a form proportional to the sum of distances on a left-side path to paths satisfying basic safety requirements. The vehicle control apparatus may have a strategy to select a path having a high risk judgment score. 
       FIG.  9    is a view illustrating generation of a bypass path and modification of the bypass path according to an embodiment of the present disclosure. 
     The vehicle control apparatus may generate a primary bypass path  414  when a reference path  412  of a vehicle  411  is impeded by another vehicle  413 . When the reference path  412  is impeded by the other vehicle  413 , the vehicle control apparatus may control the vehicle  411  such that the vehicle  411  travels along the primary bypass path  414 . The vehicle control apparatus may set the first bypass path  414  to a new reference path  422 . 
     The vehicle control apparatus may change the new reference path  422  of the vehicle  411  to modify the primary bypass path  414  of the vehicle  411 . The vehicle control apparatus may generate a secondary bypass path  424  when the vehicle  421  is impeded by another vehicle  423  while travelling along the new reference path  422  corresponding to the primary bypass path  414 . When the primary bypass path  414  is impeded by the other vehicle  423 , the vehicle control apparatus may control the vehicle  411  such that the vehicle  411  travels along the secondary bypass path  424 . 
     The vehicle  411  may move farther away from the existing path with an increase in the detour distance of the vehicle  411 . As the detour distance of the vehicle  411  is increased, time during which the vehicle  411  stays in a bypass path driving state may be increased, and therefore the vehicle  411  may have a high possibility of encountering an unpredictable situation. As prediction uncertainty decreases, a driving strategy and response to the corresponding situation may be effective. Accordingly, the detour distance may preferably be short to reduce prediction uncertainty. 
     The vehicle control apparatus may generate a plurality of bypass paths. The vehicle control apparatus may calculate the shortest distance between the plurality of bypass paths and points on the reference paths  412  and  422 . The vehicle control apparatus may configure a bypass distance score to have a higher score with a decrease in the distance between the plurality of bypass paths and the points on the reference paths  412  and  422 . The vehicle control apparatus may output bypass distance scores for the plurality of paths. 
       FIG.  10    is a view illustrating a method of comparing the similarity between trace sets of a plurality of bypass paths according to an embodiment of the present disclosure. 
     The vehicle control apparatus may set a bypass path  434  of a vehicle  431  using traces  433  of a plurality of preceding vehicles  432  ahead of the vehicle  431 . The vehicle control apparatus may observe how the plurality of preceding vehicles  432  travelling along the same path as the vehicle  431  respond to a bypass situation and may make reference when determining the bypass path  434  of the vehicle  431 . 
     The vehicle control apparatus may collect a plurality of traces  443  of the plurality of preceding vehicles  432  and may calculate a bypass path  444 . The vehicle control apparatus may set a bypass path  454  such that the bypass path  454  is substantially the same as one trace  453  among the plurality of traces  443  of the plurality of preceding vehicles  432 . 
     The vehicle control apparatus may calculate the bypass path  444  by tracking the plurality of preceding vehicles  432  during a plurality of frames and determining whether the plurality of preceding vehicles  432  consistently precede the vehicle  431 . The vehicle control apparatus may determine whether the plurality of preceding vehicles  432  travel along the same path. When the plurality of preceding vehicles  432  consistently precede the vehicle  431  and travel along the same path, the vehicle control apparatus may store the traces of the plurality of preceding vehicles  432  during the plurality of frames. 
     The vehicle control apparatus may compare the similarity between the plurality of paths generated according to the method described above with reference to  FIG.  7    and the traces of the plurality of preceding vehicles  432 . The similarity comparison may be performed by calculating distances from points forming the plurality of traces to feet of vertical lines having the shortest distance to the plurality of paths. 
     The vehicle control apparatus may set a path having the highest similarity to the traces of the plurality of preceding vehicles  432  among the plurality of paths to a preferred bypass path. The vehicle control apparatus may allow a path having a higher similarity to have a higher preceding vehicle trace score. The vehicle control apparatus may output preceding vehicle trace scores for the plurality of paths and the traces of the plurality of preceding vehicles  432 . 
       FIG.  11    is a flowchart illustrating a method of determining a final path among a plurality of bypass paths according to an embodiment of the present disclosure. 
     In operation  510 , the vehicle control apparatus may generate multiple paths. 
     In operation  520 , the vehicle control apparatus may generate a loss function. In detailed operation  521  included in operation  520 , the vehicle control apparatus may calculate a risk based loss value. In detailed operation  522  included in operation  520 , the vehicle control apparatus may calculate a detour distance based loss value. In detailed operation  523  included in operation  520 , the vehicle control apparatus may calculate a preceding vehicle trace based loss value. 
     In operation  530 , the vehicle control apparatus may convert the loss values into scores by using the loss function. In operation  540 , the vehicle control apparatus may select the final path. 
     The vehicle control apparatus, when finally determining a bypass path, may consider the risk score, the detour distance score, and the preceding vehicle trace score calculated in operation  520 . The vehicle control apparatus may configure the loss function such that a path having a high score is selected. For example, the vehicle control apparatus may select a path in which the sum of the three scores has a maximum value as the bypass path. 
     The vehicle control apparatus may provide priorities depending on the importance of factors considered when the loss values are converted into the scores. For example, a risk level may be important because it is directly connected with actual driving stability, a predictable response may be performed with a decrease in detour distance, and a preceding vehicle may not exist. The vehicle control apparatus may assign priorities in the sequence of a risk level, a detour distance, and a preceding vehicle trace. 
     The vehicle control apparatus may assign weighting values to the factors considered when the loss values are converted into the scores and may configure the loss function to add the scores in which the weighting values are reflected. For example, a risk level may have a weighting value of 5 because the risk level is directly connected with actual driving stability, a detour distance may have a weighting value of 3 because a predictable response is performed with a decrease in the detour distance, and a preceding vehicle may have a weighting value of 1.5 because the preceding vehicle does not exist in some cases. The vehicle control apparatus may multiply the risk score by a weighting value of 5, may multiply the detour distance score by a weighting value of 3, may multiply the preceding vehicle trace score by a weighting value of 1.5, and may calculate the sum of the scores in which the weighting values are reflected. 
       FIG.  12    is a view illustrating a method of determining a final path among a plurality of bypass paths according to an embodiment of the present disclosure. 
     The vehicle control apparatus may calculate risk scores, detour distance scores, and preceding vehicle trace scores of a plurality of paths. The vehicle control apparatus may calculate the risk score of path  1  as 45, may calculate the detour distance score of path  1  as 37, and may calculate the preceding vehicle trace score of path  1  as 85. The vehicle control apparatus may calculate the risk score of path  2  as 55, may calculate the detour distance score of path  2  as 47, and may calculate the preceding vehicle trace score of path  2  as 75. The vehicle control apparatus may calculate the risk score of path N as 35 (N being a natural number of 3 or larger), may calculate the detour distance score of path N as 47, and may calculate the preceding vehicle trace score of path N as 75. 
     The vehicle control apparatus may assign weighting values to the risk scores, the detour distance scores, and the preceding vehicle trace scores of the plurality of paths and may calculate weighted average scores of the plurality of paths by using the scores to which the weighting values are assigned. The vehicle control apparatus may calculate the weighted average score of path  1  as 79.5. The vehicle control apparatus may calculate the weighted average score of path  2  as 82.3. The vehicle control apparatus may calculate the weighted average score of path N as 75.5. 
     The vehicle control apparatus may compare the weighted average scores of the plurality of paths and may select a path having the highest weighted average score as a bypass path  550 . The vehicle control apparatus select path  2  having the highest weighted average score among path  1 , path  2 , and path N as the bypass path  550 . 
       FIG.  13    is a flowchart illustrating a method of evaluating a bypass path according to an embodiment of the present disclosure. 
     In operation  510 , the vehicle control apparatus may generate multiple paths. 
     In operation  520 , the vehicle control apparatus may generate a loss function. 
     In detailed operation  521  included in operation  520 , the vehicle control apparatus may calculate a risk based loss value. 
     In detailed operation  522  included in operation  520 , the vehicle control apparatus may calculate a detour distance based loss value. 
     In detailed operation  523  included in operation  520 , the vehicle control apparatus may calculate a preceding vehicle trace based loss value. 
     In operation  610 , the vehicle control apparatus may determine whether a loss value of an existing alternative path is greater than a loss value of a newly generated alterative path. The vehicle control apparatus may compare the loss value of the existing alternative path and the loss value of the newly generated alternative path when evaluating a bypass path in the same way as when evaluating a final bypass path. The vehicle control apparatus may compare a score of the existing alternative path and a score of the newly generated alternative path. The vehicle control apparatus may proceed to operation  620  when the loss value of the existing alternative path is greater than the loss value of the newly generated alterative path (operation  610 —Yes). The vehicle control apparatus may proceed to operation  630  when the loss value of the existing alternative path is less than or equal to the loss value of the newly generated alterative path (operation  610 —No). 
     In operation  620 , the vehicle control apparatus may follow the newly generated alternative path. When the loss value of the existing alternative path is greater than the loss value of the newly generated alterative path, the vehicle control apparatus may determine that a detour to the existing bypass path is impossible due to a change in surroundings. When the loss value of the existing alternative path is greater than the loss value of the newly generated alterative path, the vehicle control apparatus may modify the bypass path to the newly generated alternative path. 
     In operation  630 , the vehicle control apparatus may follow the existing alternative path. 
     When the vehicle control apparatus first generates a bypass path, an integrated lane may be a reference lane. The vehicle control apparatus may calculate a detour distance from the reference lane. The vehicle control apparatus may set the existing bypass path to the reference lane after evaluating the bypass path. The vehicle control apparatus may calculate a new bypass path by calculating the detour distance based on the existing bypass path. The vehicle control apparatus may evaluate a bypass path calculated such that a better path is selected in real time. 
       FIG.  14    is a flowchart illustrating a determination method of releasing a bypass situation according to an embodiment of the present disclosure. 
     In operation  710 , the vehicle control apparatus may control a vehicle in a bypass situation. The bypass situation may be maintained while the vehicle is in a bypass section. The bypass section may be a set of lane links including the start point and the end point of a bypass path of the vehicle and a set of road links belonging to the corresponding lane links. 
     In operation  720 , the vehicle control apparatus may determine whether the bypass situation of the vehicle is ended. The vehicle control apparatus may determine whether to drive the vehicle on the current lane without maintaining detour any more due to ending of the bypass section or a change in surrounding circumstances. 
     The vehicle control apparatus may determine whether to end the bypass section, depending on whether the vehicle deviates from the lane link set and the road link section belonging to the start point and the end point of the bypass path and whether the vehicle follows the existing global path. The vehicle control apparatus may proceed to operation  730  when the bypass situation of the vehicle is ended (operation  720 —Yes). The vehicle control apparatus may proceed to operation  740  while the bypass situation of the vehicle is maintained (operation  720 —No). 
     In operation  730 , the vehicle control apparatus may follow the existing path. The vehicle control apparatus may transition to a general driving state when the vehicle deviates from the end point of the bypass path and follows the existing global path. 
     In operation  740 , the vehicle control apparatus may calculate a loss function. In sub-operation  741  included in operation  740 , the vehicle control apparatus may calculate a bypass path time loss value. In sub-operation  742  included in operation  740 , the vehicle control apparatus may calculate a bypass path distance loss value. The vehicle control apparatus may calculate a time loss value and a distance loss value for the case of maintaining a target lane and the case of travelling on the current lane. 
     In the case where the vehicle cannot follow the global path to reach a destination when consistently travelling along the bypass path, the time loss value and the distance loss value may be extra time and extra distance caused by changing the global path. For example, the case where the vehicle has to enter the first lane for a U-turn immediately after making a left turn, but cannot enter the first lane due to other waiting vehicles on the first lane may correspond to the case where the vehicle cannot follow the global path to reach the destination. 
     When the vehicle can follow the global path, an alternative path or a bypass path may naturally converge to the global path because a path having a small loss value is selected in a bypass path evaluation step. 
     In operation  750 , the vehicle control apparatus may determine whether an output value of the loss function is greater than a threshold value. The vehicle control apparatus may proceed to operation  760  when the output value of the loss function is greater than the threshold value (operation  750 —Yes). The vehicle control apparatus may proceed to operation  730  when the output value of the loss function is less than or equal to the threshold value (operation  750 —No). 
     In operation  760 , the vehicle control apparatus may follow an alternative path. In the case where the vehicle deviates from the end point of a bypass path, but fails to enter the existing global path due to other objects, the vehicle control apparatus may maintain bypass driving until entering the global path while consistently modifying the bypass path. 
       FIG.  15    illustrates a computing system according to an embodiment of the present disclosure. 
     Referring to  FIG.  10   , the computing system  1000  may include at least one processor  1100 , a memory  1300 , a user interface input device  1400 , a user interface output device  1500 , storage  1600 , and a network interface  1700 , which are connected with each other via a bus  1200 . 
     The processor  1100  may be a central processing unit (CPU) or a semiconductor device that processes instructions stored in the memory  1300  and/or the storage  1600 . The memory  1300  and the storage  1600  may include various types of volatile or non-volatile storage media. For example, the memory  1300  may include a ROM (Read Only Memory)  1310  and a RAM (Random Access Memory)  1320 . 
     Thus, the operations of the method or the algorithm described in connection with the embodiments disclosed herein may be embodied directly in hardware or a software module executed by the processor  1100 , or in a combination thereof. The software module may reside on a storage medium (that is, the memory  1300  and/or the storage  1600 ) such as a RAM, a flash memory, a ROM, an EPROM, an EEPROM, a register, a hard disk, a removable disk, or a CD-ROM. 
     The exemplary storage medium may be coupled to the processor  1100 , and the processor  1100  may read information out of the storage medium and may record information in the storage medium. Alternatively, the storage medium may be integrated with the processor  1100 . The processor  1100  and the storage medium may reside in an application specific integrated circuit (ASIC). The ASIC may reside within a user terminal. In another case, the processor  1100  and the storage medium may reside in the user terminal as separate components. 
     In response to a situation in which a travel path of an autonomous vehicle is blocked, the present disclosure may replace the travel path with a bypass path and may allow the autonomous vehicle to travel along the bypass path. Accordingly, the present disclosure may control the autonomous vehicle to travel along the bypass path in various situations in which the autonomous vehicle needs to bypass during travel, thereby improving driving safety and stability. 
     Furthermore, the present disclosure may set a plurality of bypass paths and may select one of the plurality of bypass paths in real time, based on a risk level, a detour distance, and a trace of a preceding vehicle in a drivable area. Accordingly, the present disclosure may select a bypass path along which an autonomous vehicle safely and efficiently reaches a destination, thereby improving driving safety and efficiency. 
     In addition, the present disclosure may provide various effects that are directly or indirectly recognized. 
     Hereinabove, although the present disclosure has been described with reference to exemplary embodiments and the accompanying drawings, the present disclosure is not limited thereto, but may be variously modified and altered by those having ordinary skill in the art to which the present disclosure pertains without departing from the spirit and scope of the present disclosure claimed in the following claims. 
     Therefore, the exemplary embodiments of the present disclosure are provided to explain the spirit and scope of the present disclosure, but not to limit them, so that the spirit and scope of the present disclosure is not limited by the embodiments.