JP2718033B2 - Autonomous traveling vehicle control device - Google Patents

Description

Description: Object of the Invention (Industrial application field) The present invention relates to a control device for an autonomous traveling vehicle that autonomously travels on a planned traveling path in an autonomous traveling mode, and particularly to a manual traveling mode. The present invention also relates to a control device for an autonomous traveling vehicle which is maintained in a standby state which can be switched to an autonomous traveling mode at any time. (Prior Art) In recent years, various types of self-propelled vehicles that autonomously travel on a planned traveling road have been proposed. In such a conventional autonomous vehicle, not only an autonomous traveling mode but also a so-called manual traveling mode in which a person is boarded and the vehicle travels by a human operation is provided. (Problems to be Solved by the Invention) However, in the manual traveling mode, since the occupant makes all traveling judgments, all traveling judgments and related control operations by a control unit incorporating a computer or the like are stopped. I have to. However, for example, after driving in the manual driving mode determined by the passenger after the autonomous driving in the autonomous driving mode, if the autonomous driving mode is set, the current position information, the destination and information on the planned driving route to the destination, etc. This information must be given again, which is very troublesome for the passenger. SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and has as its object to provide an autonomous traveling vehicle control device capable of smoothly and surely shifting to an autonomous traveling mode by a simple operation from a manual traveling mode. . [Structure of the Invention] (Means for Solving the Problems) Means provided by the present invention to achieve the above object are:
Information collecting means for collecting information related to the travel of the own vehicle, control means having an autonomous driving mode for autonomously driving based on the collected information and a manual driving mode for manually driving, and a brake pedal or an accelerator pedal. Switching means for switching the autonomous traveling mode to the manual traveling mode when the vehicle is depressed by a predetermined amount, and capturing means for performing a calculation based on the information collected by the information collecting means and capturing a current position of the own vehicle are provided. It is characterized by having. (Operation) The present invention switches the autonomous traveling mode to the manual traveling mode when the brake pedal or the accelerator pedal is depressed by a predetermined amount, and sets the autonomous traveling mode to the manual traveling mode.
The information collecting means collects information, and the capturing means captures the current position. Thereby, it is possible to easily shift from the manual traveling mode to the autonomous traveling mode. (Example) Hereinafter, an example of the present invention will be described in detail with reference to the drawings. FIG. 1 is a block diagram showing a main part of the present invention, and FIG. 2 is a block diagram showing an entire configuration of an autonomous traveling control device according to the present invention. First, the overall configuration will be described with reference to FIG. 2. The autonomous traveling vehicle control device shown in FIG. 2 appropriately determines a road condition in a traveling direction detected by a camera, a sensor, or the like, for example, to a set destination. An image processing unit 100 that performs control for autonomously and autonomously traveling a vehicle headed for a vehicle, capturing an image in the traveling direction of the vehicle and performing image processing, an ultrasonic sensor, a laser radar, and the like. By detecting objects such as the traveling direction and the side of the vehicle, such as a preceding vehicle, a guardrail, an obstacle, and the like, and also detecting and processing wheel speeds and the like, and a vehicle for traveling the vehicle unmanned. Actuator control unit 300 that has actuators for operating steering, accelerator, brake, blinker, etc., and controls these, and map information storage that stores map information to the destination 400, a travel control unit 500 that controls the actuator control unit 300 and the like so that the vehicle travels toward the destination so as not to collide with an obstacle or the like based on information from each unit. Along with inputting information about the ground, and a man-machine interface unit 600 that displays images and other information from the image information processing unit 100,
Auxiliary control unit 700 with functions such as limiting the maximum speed
And a data recording unit 800 that records the status of each part of the vehicle in the event of a collision or emergency braking, such as an airplane flight recorder. The image information processing unit 100 has a set of two cameras 101 and 103. The cameras 101 and 103 are provided, for example, on the left and right of the front part of the vehicle, and capture a stereo image in the traveling direction of the vehicle, that is, a stereo perspective image.
The oblique images captured by the cameras 101 and 103 are supplied to an image processing computer 105 and subjected to image processing, whereby parallax is determined to determine the presence or absence of an obstacle, and the distance and direction to the obstacle are determined. Used to measure,
Further, the slope image is converted into a planar image by the image processing computer 105, that is, the image is converted into an inverse perspective. The image processing computer 105 detects, for example, a white line or a roadside zone, a center line, or the like, which is a pair of vehicle guide lines drawn on a road, from the planar image, and measures the position. More specifically, by detecting a white line or the like on the road, the relative relationship between the road and the vehicle, that is, the distance from the vehicle to the left white line, the distance to the right white line, the traveling direction of the vehicle and the connection between the road and the road. The angle and the like are calculated, and the direction and curvature of the curve of the road are obtained from these values. Before the intersection, the distance to the intersection is determined by measuring how the white line is cut. The distance, the angle, and the like obtained by the image processing computer 105 are supplied to the local vehicle position estimating unit 107, whereby the positional relationship between the road and the vehicle, that is, the local vehicle position can be estimated. It should be noted that the local vehicle position refers to the vehicle position locally narrowly obtained by the image processing in the image processing computer 105 as described above. In addition, the host vehicle position roughly determined as described later with respect to the local host vehicle position is referred to as a global host vehicle position. In addition, in order to take a wide angle of view, about three sets of cameras are installed and switched to be used, so that the right front, the left front,
The above parameters can be obtained from the image in front. The detection processing unit 200 uses an ultrasonic sensor, a laser radar, and the like, and detects an object such as a traveling direction or a side, such as a preceding vehicle, a guardrail, and an obstacle, and also detects a wheel speed and the like. However, this makes it possible to run to some extent even when there is no image information from the image information processing unit 100, thereby trying to fulfill a fail-safe role. The detection processing unit 200 includes four ultrasonic sensors 201, 203, and 20 provided at four locations on the side, front, rear, left, and right of the vehicle.
The outputs of these ultrasonic sensors 201 are supplied to a fail-safe local host vehicle position detecting unit 215, which measures the distance between the vehicle and the guardrail on the road, thereby obtaining the image. The same parameters as those obtained by the information processing unit 100 can be measured. The detection processing unit 200 is provided at the front of the vehicle, and detects an obstacle or the like existing in front of the vehicle.
And a forward ultrasonic sensor 210, and the outputs thereof are supplied to a fail-safe obstacle determination unit 217. The laser radar 209 and the front ultrasonic sensor 210 also calculate the distance to the obstacle, and even when the laser information cannot be recognized by the cameras 101 and 103 of the image information processing unit 100, the laser radar
When the 209 detects an obstacle, the running of the vehicle is temporarily stopped or decelerated. Further, the detection processing unit 200 has a pair of wheel speed sensors 211 and 213 provided on the left and right of the rear wheel, and the outputs of these sensors are supplied to a wheel speed data processing unit 218, which further processes the wheel speed data. Unit 218 to Global Vehicle Position Estimation Unit 219
Is supplied to The wheel speed sensors 211 and 213 detect the rotation of the wheel, and generate thousands (specifically, 1000 to 4000) of pulses for each of the right and left wheels every one rotation of the wheel in synchronization with the rotation. . Therefore, if the difference between the numbers of the two pulses generated for each of the left and right wheels is calculated, the difference in the traveling distance is obtained. From this difference, it can be determined whether or not the vehicle is traveling in a curve. The traveling distance of the left and right wheels is the traveling distance of the vehicle as it is. Therefore, the displacement of the vehicle can be obtained by calculating these information every moment.
More specifically, the attitude of the vehicle at a certain point in time, that is, relative position information of the vehicle with reference to the position, that is, information such as relative position in X and Y coordinates and θ can be obtained. If the position of the preceding vehicle is known, the current position of the running vehicle can be always detected by sequentially performing the wheel speed processing. However, since errors are accumulated, the measurement error increases as the traveling distance increases. The approximate vehicle position determined in this way is the global vehicle position. The actuator control unit 300 includes various actuators necessary for running the vehicle unattended, that is, an actuator unit including a steering actuator 301 for steering, a throttle actuator 303 corresponding to an accelerator, a brake actuator 305, and a blinker driving unit 307. 306, and actuator link switching means 308 for switching the link mechanism of each actuator to autonomous traveling or manual traveling, and these actuators are controlled by the actuator control unit 309 based on control information from the traveling control unit 500. Control. When the vehicle is an AT car and only runs forward, only the above-described actuator may be used, but when controlling an MT car or a reverse movement, an actuator for operation such as a clutch or a shift lever is also required. . The actuator control unit 300 receives an acceleration / deceleration command or a target vehicle speed command from the traveling steering control unit 505, and controls an accelerator, a brake, and the like. The steering control is similarly operated upon receiving a rotation command to the right or left or a target steering angle command. The map information storage unit 400 includes a map data storage unit 401 storing map information on the destination, map information to the destination, for example, map information such as an intersection position existing on a road to the destination, an intersection distance, and the like. A map information access control unit 403 controls access to the map data storage unit 401 from the travel control unit 500. The traveling control unit 500 determines the road information of the traveling direction detected by the image information processing unit 100 and the detection processing unit 200 as appropriate and refers to the map information from the map information storage unit 400, and outputs the information from the man-machine interface unit 600. The actuator control unit 300 is driven and controlled to drive the vehicle toward the input destination, and obstacle data is supplied from the image processing computer 105 of the image information processing unit 100. An obstacle avoiding direction determining unit 501 that determines an avoiding direction of an obstacle based on the map information from the map information storage unit 400, the global own vehicle position information from the global own vehicle position estimating unit 219 of the detection processing unit 200, Correction data from the local vehicle position estimating unit 107 of the image information processing unit 100 and information such as destination information from the man-machine interface unit 600 are supplied. Develops global driving strategy information including the route to the destination, etc., and processes control information such as information on driving operations such as straight ahead, right / left turn, deceleration, acceleration, and stop, and distance information to intersections according to this information. A driving command unit 503, which is a planner to
The control information from the travel command unit 503, the distance from the road edge from the local vehicle position estimation unit 107 of the image information processing unit 100,
Local own vehicle position information including an angle and the like; obstacle avoiding direction information from the obstacle avoiding direction determining unit 501; vehicle posture (position) information including vehicle displacement from the wheel speed data processing unit 218 of the detection processing unit 200; Local vehicle position information including the distance and angle from the road edge from the fail-safe local vehicle position detection unit 215 of the detection processing unit 200, distance information to the obstacle from the fail-safe obstacle determination unit 217, incidental control The control section 300 is supplied with information and the like from the section 700, and supplies various control signals necessary for controlling the actuator control section 300 based on the information, for example, information such as target vehicle speed and target steering angle information to the actuator control section 300. And a traveling steering control unit 505 for performing steering control and the like by the control unit. More specifically, when destination information is input from the man-machine interface unit 600, the travel command unit 503 searches for a route to the destination while accessing the map information storage unit 400, and determines the shortest route. . Then, travel control information is created while comparing the determined information on the shortest route with the global vehicle position information calculated based on the information detected by the wheel speed sensors 211 and 213. For example, when approaching an intersection, the vehicle outputs an approximate deceleration command or outputs information such as "how many meters to turn left" to the traveling steering control unit 505. Control of the actuator in the traveling steering control unit 505 is performed by intelligent control such as fuzzy control. That is, it is controlled in accordance with the production rules described in the format of "if ... then ...". In addition, the direction of the obstacle avoidance is determined based on the distance and the direction to the obstacle by the image information processing unit 100. The man-machine interface unit 600 includes a keyboard 601 for inputting destination information and the like, a CRT display 603 for displaying a map to the destination and displaying various other information, for example, information to an intersection, and an autonomous driving mode. It has a changeover switch 604 for switching between a manual driving mode, a changeover switch 606 for changing a destination, and a destination input means 608 for inputting destination information. The keyboard 601 may use a mouse, an image scanner, a digitizer, and the like in addition to a normal keyboard.
Further, the man-machine interface unit 600 may include a speech recognition or speech synthesis device as a man-machine interface. The auxiliary control unit 700 has an emergency brake actuator 701, and the emergency brake actuator 701 operates in parallel with the brake actuator 305 for normal traveling,
Improves safety. The emergency brake actuator 701 is supplied with an external emergency brake signal received by the antenna 705 via the receiver 707 and the control unit 703, or an emergency brake switch 709 provided inside the vehicle.
When the operation signal is supplied from the control unit 703 via the control unit 703, it operates regardless of the control of the travel control unit 500, and stops the vehicle. Further, the auxiliary control unit 700 includes a maximum vehicle speed limiter 711, a speed setting unit 713 for setting the maximum vehicle speed for the maximum vehicle speed limiter 711, and a vehicle speed sensor 714 for supplying the actual vehicle speed information to the maximum vehicle speed limiter 711. And can travel at the traveling vehicle speed set by the speed setting unit 713. This maximum vehicle speed limiter 711 is for setting the maximum vehicle speed when the occupant of the vehicle wants to run slowly, and the set maximum vehicle speed information is supplied to the traveling steering control unit 505, and the traveling steering control unit At 505, control is performed so as not to exceed this speed. The maximum vehicle speed is determined by the driving command section.
503 can be set for each road. If the vehicle speed exceeds the set maximum vehicle speed, the vehicle speed sensor 714 detects the vehicle speed.
The emergency brake actuator 701 is controlled by operating the emergency brake actuator 701 so as to operate the emergency brake. The data recording unit 800 includes a data recording unit 801 and a G that include a memory or the like for storing the status of each part of the vehicle at the time of a collision, emergency braking, etc., such as a flight recorder.
It has a sensor 803. It is used for later elucidating the cause or the like based on the data stored in the data recording unit 801. Next, the essential parts of the present invention will be described with reference to FIG. First
In the figure, a changeover switch 604 is built in the man-machine interface 600 and is a switching means for switching between an autonomous traveling mode and a manual traveling mode. When the changeover switch 604 is switched to set to the autonomous traveling mode, the vehicle travels autonomously based on information from the image information processing unit 100 as information collecting means. When the changeover switch 604 is switched to set to the manual traveling mode, the vehicle travels based on the operation of the passenger. The lamp 108 is turned on based on the output of the local vehicle position determining unit 107 when the capturing means, that is, the local vehicle position determining unit 107 captures the current position. Therefore, when the lamp 108 is turned on, it indicates that autonomous traveling is possible. Change switch 606 to change destination
The destination input means 608 for inputting destination information is incorporated in the man-machine interface 600. When the change switch 606 is operated, the destination input is performed from the current vehicle position at the time when the switch operation is performed. Travel control is started toward the new destination input by means 608. An actuator unit 306 including a steering actuator 301, a throttle actuator 303, a brake actuator 305, and the like, and an actuator link switching unit 308 for switching a link mechanism of each actuator between autonomous traveling and manual traveling are built in the actuator control unit 300. It is controlled based on a control command from the traveling control unit 500. That is, when the autonomous traveling mode is set based on the switching of the changeover switch 604, the actuator unit 306 is controlled based on a command from the traveling control unit 500. When the changeover switch 604 is switched to the manual traveling mode, the actuator link switching means 308 is switched to a manual link mechanism, and operates according to the operation of the occupant. The above-described ultrasonic sensors 201, 203, 205, 207, the laser radar 209, and the front ultrasonic sensor 210 function as information collecting means for collecting information related to the traveling of the own vehicle. Functions as a capturing unit for capturing the current position of the. Next, the operation of the present invention will be described. First, a process until the autonomous traveling is started will be described with reference to FIG. Initial setting is made in step 31, and the changeover switch 604 is operated to set the self-sustained traveling mode. When the destination is entered in step 33, step
At 35, a route to the destination, that is, a planned traveling route is searched. In step 37, autonomous traveling is started based on the above-described planned traveling path. Next, the operation in the autonomous driving mode will be described with reference to FIG. When the autonomous traveling mode is set in step 41, the process proceeds to step 42, where it is determined whether or not the changeover switch 604 has been switched, that is, whether or not the autonomous traveling mode has been switched to the manual traveling mode. When the changeover switch 604 is switched in step 42, the process proceeds to step 43 and the mode is set to the manual traveling mode. In step 42, the changeover switch 60
If the switching operation of step 4 is not performed, proceed to step 44,
The current vehicle position is calculated by driving the capturing means. Steps
At 45, the actuator units 306 such as the steering actuator 301, the throttle actuator 303, and the brake actuator 305 are driven to autonomously travel on the planned traveling path. In step 46, it is determined whether or not the destination change command, that is, the change switch 606 has been operated. If the change switch 606 has not been operated, the process returns to step 42 again, and the autonomous operation is performed toward the initially set destination. Continue running. Step 46
If the destination change command is issued by operating the change switch 606, the process proceeds to step 47. When a new destination is input from the destination input means 608 in step 47, the process proceeds to step 48, where a route to the new destination is searched. Returning from step 48 to step 42, the autonomous driving to the new destination is continued. Next, the operation in the manual traveling mode will be described with reference to FIG. In step 51, by operating the changeover switch 604, the mode is set to the manual traveling mode. When the vehicle is set to the manual traveling mode, the vehicle travels based on the operation of the passenger. In step 52, the information collection means and the capture means are driven following the autonomous driving mode to calculate the current vehicle position. In step 53, the shortest distance R between the planned traveling route, that is, the route searched during the autonomous traveling and the current position of the vehicle is calculated, and the traveling direction of the vehicle is calculated.
In step 54, if the calculated minimum distance R is short and the calculated traveling direction matches the direction to go to the destination, it is determined that the vehicle is traveling on the planned traveling path, and the flow proceeds to step 55. move on. In step 55, the lamp 108 is turned on to display that autonomous traveling is possible. Therefore, when the changeover switch 604 is switched in this state, the mode easily shifts from the manual driving mode to the autonomous driving mode. If it is determined in step 54 that the vehicle is not traveling on the planned traveling route, the process proceeds to step 56, where the changeover switch 604
It is determined whether or not the driving mode switching operation has been performed. If the driving mode switching operation has not been performed in step 56, the process returns to step 52 again, and the traveling in the manual traveling mode is continued. If the driving mode switching operation is performed in step 56, that is, if the autonomous driving mode is set by operating the changeover switch 604, the process proceeds to step 57, and the route search is performed again. That is, the position at the time point when the autonomous driving mode is set is set as the current own vehicle position, and a planned traveling route from the current own vehicle position to a preset destination is searched. In step 58, the vehicle travels autonomously on the planned traveling path searched in step 57. FIG. 6 is a detailed flowchart for calculating the shortest distance from the planned traveling road to the current vehicle position in step 53 shown in FIG. Hereinafter, the calculation of the shortest distance from the planned traveling path to the current vehicle position will be described. In step 61, the current vehicle position is set as (X ₀ , Y ₀ ) on two-dimensional coordinates. Step 65
Then, as shown in FIG. 7, the planned traveling paths Pj constituting the route from the starting point to the destination are displayed as P ₁ , P ₂ ... _PN for each traveling path, and the respective traveling paths P ₁ , P ₂ , ...... P _N of the start point and the end point and the end point of the coordinates, respectively (X _s, Y _s) and (X _e, Y _e) to display as. Such a planned traveling path Pj, that is, each traveling path P ₁ ,
P ₂ …… P _N is the shortest distance from the current vehicle position (X ₀ , X ₀ )
Find Yj. As shown in FIG. 8, the travel path P ₁ the travel path P ₁ and the current vehicle position P ₀ for example (X _0, Y ₀₎ shortest distance between Y (j =
The case of calculating 1) will be described. Coordinates (X _s, Y _s) of the starting point S of the traveling path P ₁ and the coordinates of the end point _E (X _e, Y _e)
Then, the distance D from the start point S to the end point E is obtained as follows. Then the distance D is divided at predetermined intervals d, the coordinates of the position Q _d away from the start point S by a distance _d (X d, Y d) When, X _d and Y _d is determined as follows. X _d = (d / D) × (X _e −X _s ) + X _s Y _d = (d / D) × (Y _e −Y _s ) + Y _s Therefore, the difference between the position Q _d and the current vehicle position P ₀ is obtained. The distance _Rd is obtained as follows. Minimum in this way the distance D to determine the respective distances R _d and a predetermined distance d for each point Q and the current vehicle position P ₀ obtained by dividing the respective distances R _d where these correspond to the points Q to those with roadway P ₁ calculated current as the shortest distance R (j = 1) of the vehicle position P _0. Hereinafter, the shortest distance is similarly calculated for the other traveling paths. That is, the running path _{P 2, P 3, ...... P} N and the current minimum distance R ₂ between the vehicle position P _0, R ₃ ...... R _N to be calculated. Step 67
Each of the shortest distances R ₁ , R ₂ , R ₃ …… R _N
Planned traveling path Pj the smallest among the (j = 1,2, ... N) and is calculated as the shortest distance R between the current vehicle position P _0. When the shortest distance R is calculated as described above, the process proceeds to step 69, and the calculation operation is stopped. In the calculation of the shortest distance R described above, the shortest distance R is calculated in consideration of all running paths existing on the route from the starting point to the destination, but the lamp 108 is turned on. In the case, that is, when the vehicle is in the autonomous traveling enabled state, since the capturing means has captured the current position of the vehicle on the specific traveling road, the shortest distance R is calculated in consideration of only the traveling road currently traveling. You may do so. In addition, while driving in the autonomous driving mode, when the blinker is manually operated, at the next intersection, while autonomously traveling in the direction indicated by the blinker, the position of this intersection is set as the current vehicle position, It can be configured to search for a route from the newly set current vehicle position to the destination and continue autonomous traveling. Further, it is possible to provide a tread amount detecting means for detecting that the brake petal or the accelerator petal is depressed by a predetermined amount, and to configure the tread amount detecting means as a switching means for switching between the autonomous traveling mode and the manual traveling mode. That is, in the autonomous traveling mode, it can be configured to switch to the manual operation mode when the brake petal or the accelerator petal is depressed by a predetermined amount. With this configuration, emergency measures can be promptly processed,
Safety can be improved. Further, by providing the display means for displaying the autonomous traveling enabled state, it is possible to easily recognize that the currently traveling traveling path is the planned traveling path and exists on the planned traveling path. Can be. Therefore, for example, when the vehicle deviates from the planned traveling route and makes a detour in the manual traveling mode, when the display means displays the autonomous traveling enabled state when returning to the planned traveling route again after such a detour, The switching timing from the manual driving mode to the autonomous driving mode can be easily recognized. Further, the position at the time when the switch of the switch 606 for changing the destination is operated is reset as the current own vehicle position, and the destination input means 608 inputs the position from the reset current own vehicle position. Since the travel control is performed for the new destination, the change setting of the destination can be easily executed. [Effects of the Invention] As described above, according to the present invention, even when the mode is switched from the autonomous traveling mode to the manual traveling mode in accordance with the switching of the switching unit, the information collecting unit continues to operate according to the traveling of the own vehicle. By collecting the information and capturing the current position by the capturing means, it is possible to maintain a standby state that can be switched to the autonomous driving mode at any time, and therefore, it is possible to easily shift from the manual driving mode to the autonomous driving mode. .

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram showing a main part of the present invention, FIG. 2 is a block diagram showing an entire configuration of an autonomous traveling vehicle control device according to the present invention, and FIG. FIG. 4 is a flowchart showing a control operation in an autonomous driving mode, FIG. 5 is a flowchart showing a control operation in a manual driving mode, and FIG. 6 is a flowchart showing a control operation in a manual driving mode. FIG. 7 is a detailed flowchart for calculating the indicated shortest distance, FIG. 7 is an explanatory diagram showing the planned traveling routes existing on the route from the starting point to the destination for each traveling route, and FIG. FIG. 7 is an explanatory diagram in a case where a shortest distance from a current vehicle position is calculated. 107 Local vehicle position determination unit 108 Lamp 306 Actuator unit 308 Actuator link switching unit 500 Travel control units 604, 606 Switch 608 Destination input unit

   ────────────────────────────────────────────────── ─── Continuation of front page    (72) Inventor Norimishi Kishi               2 Takaracho, Kanagawa-ku, Yokohama-shi, Kanagawa Sun               Industrial Motor Co., Ltd.                (56) References JP-A-62-131309 (JP, A)                 JP-A-63-7705 (JP, A)                 JP-A-55-102730 (JP, A)

Claims (1)

(57) [Claims] Information collecting means for collecting information relating to the travel of the vehicle, control means having an autonomous driving mode for autonomously driving based on the collected information and a manual driving mode for manually driving, and a brake pedal or an accelerator pedal. A switching unit that switches the autonomous traveling mode to the manual traveling mode when the vehicle is depressed by a predetermined amount; and a capturing unit that performs a calculation based on the information collected by the information collecting unit and captures a current position of the vehicle. An autonomous traveling vehicle control device, characterized in that: 2. 2. The autonomous traveling vehicle control device according to claim 1, wherein the acquisition unit includes a display unit that displays an autonomous traveling enabled state when the current position of the own vehicle is acquired.