Vehicle time correction device

Abstract

To ensure that occupants hardly feel uncomfortable in a vehicle that uses an internal time for automatic driving control, even when the internal time needs to be significantly corrected.SOLUTION: A time correction device for vehicles comprises: a time acquisition unit 110 that successively acquires absolute time information received from a positioning satellite; a time synchronization control unit 130 that successively synchronizes the internal time to the absolute time on the basis of the acquired absolute time information; a time control unit 120 that autonomously complements the internal time in the host vehicle when acquisition of the absolute time information is interrupted; a time correction unit 150 that, when acquisition of the absolute time information is restarted after being interrupted, corrects a difference between the absolute time and the complemented internal time; and a state identification unit 140 that identifies at least one of the state in which the host vehicle is and the state of the host vehicle itself. The time correction unit 150 changes the upper-limit value of a correction amount per round of correction by the time correction unit 150, in accordance with the state identified by the state identification unit 140.SELECTED DRAWING: Figure 2

Description

Technical Field

[0004] , , , ,

[0005] , , ,

[0003] , , , ,

[0001] The present disclosure relates to a vehicle time correction device.

Background Art

[0002] There is known a technique for correcting the internal time of a device based on time information that is more accurate than the internal time measured by the built-in clock of the device and is acquired from outside the device. Patent Document 1 discloses an artificial satellite that synchronizes an internal clock to be generated with a reference clock received from a GPS receiver. In Patent Document 1, if there is an abnormality in the soundness of the reference clock, the satellite internal time is measured based on the reference clock and the synchronization process is stopped. In Patent Document 1, when synchronizing the internal clock with the reference clock, in order to minimize the impact on the software operation, a sudden time variation is prevented from occurring. Specifically, an upper limit is set for the phase difference between the reference clock and the internal clock that can be reduced at one time, and synchronization is performed by reducing the phase difference in multiple times. That is, correction is performed by setting an upper limit for the correction amount for one instance of the internal time.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] Unlike an artificial satellite that orbits at a constant speed on a fixed orbit, a vehicle is required to operate according to the environment. Therefore, in a vehicle that uses the internal time for automatic driving control, it may be preferable in some cases to perform correction quickly without setting an upper limit for the correction amount for one instance of the internal time. On the other hand, there may also be situations where it is preferable to set an upper limit for the correction amount for one instance of the internal time and perform correction over time.

[0005] One objective of this disclosure is to provide a vehicle time correction device that makes it less likely for occupants to notice any malfunction, even when it is necessary to significantly correct the internal time in a vehicle that uses internal time for autonomous driving control. [Means for solving the problem]

[0006] The above objectives are achieved by a combination of features described in the independent claims, and the subordinate claims provide further advantageous specific examples of the disclosure. The reference numerals in parentheses in the claims indicate correspondences with specific means described in the embodiments described later as one aspect, and do not limit the technical scope of this disclosure.

[0007] To achieve the above objectives, this disclosure First The vehicle time correction device is a vehicle time correction device used in vehicles that use internal time for automatic driving control, and comprises a time acquisition unit (110) that sequentially acquires high-precision time information, which is more accurate than the internal time, received by communication from outside the vehicle; a time synchronization control unit (130) that sequentially synchronizes the internal time to the high-precision time based on the high-precision time information acquired sequentially by the time acquisition unit; and a time control unit (12) that autonomously compensates for the internal time in the vehicle when the acquisition of high-precision time information by the time acquisition unit is interrupted. 0) The system includes a time correction unit (150, 150a, 150b, 150c, 150d) that corrects the difference between the high-precision time and the internal time that was being compensated for by the time control unit when the acquisition of high-precision time information by the time acquisition unit is interrupted and then resumed, and a situation identification unit (140, 140a, 140b) that identifies at least one of the situations in which the vehicle is located and the situation of the vehicle itself, and the time correction unit changes the correction upper limit value, which is the upper limit value of the correction amount per correction by the time correction unit, according to the situation identified by the situation identification unit. The situation identification unit identifies whether or not the vehicle is in remote-controlled autonomous driving mode. The time correction unit, based on the situation identification unit's determination that the vehicle is in remote-controlled autonomous driving mode, corrects the internal time by setting a lower correction limit than when the situation identification unit determines that the vehicle is not in remote-controlled autonomous driving mode. Conversely, based on the situation identification unit's determination that the vehicle is not in remote-controlled autonomous driving mode, it corrects the internal time by setting a higher correction limit than when the situation identification unit determines that the vehicle is in remote-controlled autonomous driving mode. . To achieve the above objective, the second vehicle time correction device of this disclosure is a vehicle time correction device used in a vehicle that uses internal time for automatic driving control, comprising: a time acquisition unit (110) that sequentially acquires high-precision time information, which is more accurate than the internal time, received by communication from outside the vehicle; a time synchronization control unit (130) that sequentially synchronizes the internal time to the high-precision time based on the high-precision time information acquired sequentially by the time acquisition unit; a time control unit (120) that autonomously compensates for the internal time in the vehicle when the acquisition of high-precision time information by the time acquisition unit is interrupted; and when the acquisition of high-precision time information by the time acquisition unit is resumed after the interruption, the high-precision time and the internal time that was compensated for by the time control unit The system includes a time correction unit (150, 150a, 150b, 150c, 150d) that corrects the difference with the current time, and a situation identification unit (140, 140a, 140b) that identifies at least one of the situations in which the vehicle is located and the situation of the vehicle itself. The time correction unit changes the correction upper limit, which is the upper limit of the correction amount per correction in the time correction unit, according to the situation identified by the situation identification unit. The situation identification unit identifies the vehicle's speed as a situation. The time correction unit corrects the internal time by decreasing the correction upper limit as the vehicle's speed identified by the situation identification unit increases, and corrects the internal time by increasing the correction upper limit as the vehicle's speed identified by the situation identification unit decreases. To achieve the above objective, the third vehicle time correction device of this disclosure is a vehicle time correction device used in a vehicle that uses internal time for automatic driving control, comprising: a time acquisition unit (110) that sequentially acquires high-precision time information, which is more accurate than the internal time, received by communication from outside the vehicle; a time synchronization control unit (130) that sequentially synchronizes the internal time to the high-precision time based on the high-precision time information acquired sequentially by the time acquisition unit; a time control unit (120) that autonomously compensates for the internal time in the vehicle when the acquisition of high-precision time information by the time acquisition unit is interrupted; and a time correction unit (150, 150a, 150b, 150c) that corrects the difference between the high-precision time and the internal time compensated by the time control unit when the acquisition of high-precision time information by the time acquisition unit is resumed after an interruption. The system includes a time correction unit (140, 140a, 140b) that identifies at least one of the conditions in which the vehicle is located and the conditions of the vehicle itself, and the time correction unit changes the correction upper limit, which is the upper limit of the correction amount per correction in the time correction unit, according to the conditions identified by the conditions identification unit, the conditions identification unit (140, 140a) that identifies the shape of the road the vehicle is traveling on as a condition, and the time correction unit (150, 150a, 150c, 150d) corrects the internal time by making the correction upper limit smaller than when the road shape is a straight road when the road shape identified by the conditions identification unit is a curved road, and corrects the internal time by making the correction upper limit larger than when the road shape is a curved road when the road shape is a straight road. To achieve the above objective, the fourth vehicle time correction device of this disclosure is a vehicle time correction device used in a vehicle that uses internal time for automatic driving control, comprising: a time acquisition unit (110) that sequentially acquires high-precision time information, which is more accurate than the internal time, received by communication from outside the vehicle; a time synchronization control unit (130) that sequentially synchronizes the internal time to the high-precision time based on the high-precision time information acquired sequentially by the time acquisition unit; a time control unit (120) that autonomously compensates for the internal time in the vehicle when the acquisition of high-precision time information by the time acquisition unit is interrupted; and a time correction unit (120) that corrects the difference between the high-precision time and the internal time compensated by the time control unit when the acquisition of high-precision time information by the time acquisition unit is resumed after an interruption. The system comprises (50, 150a, 150b, 150c, 150d) and a situation identification unit (140, 140a, 140b) that identifies at least one of the situations in which the vehicle is located and the situation of the vehicle itself. The time correction unit changes the correction upper limit, which is the upper limit of the correction amount per correction in the time correction unit, according to the situation identified by the situation identification unit. The situation identification unit (140b) identifies the planned entry of the vehicle into a target curved road, which is a curved road where the occurrence of at least one of lateral acceleration and lateral jerk above a threshold is estimated. The time correction unit (150b) completes the correction of the internal time on the straight road before entering the target curved road when the situation identification unit identifies the planned entry of the vehicle into the target curved road. To achieve the above objective, the fifth vehicle time correction device of this disclosure is a vehicle time correction device used in a vehicle that uses internal time for automatic driving control, comprising: a time acquisition unit (110) that sequentially acquires high-precision time information, which is more accurate than the internal time, received by communication from outside the vehicle; a time synchronization control unit (130) that sequentially synchronizes the internal time to the high-precision time based on the high-precision time information acquired sequentially by the time acquisition unit; a time control unit (120) that autonomously compensates for the internal time in the vehicle when the acquisition of high-precision time information by the time acquisition unit is interrupted; and a time correction unit (150, 150a, 150b, 150c, 150d) that corrects the difference between the high-precision time and the internal time compensated by the time control unit when the acquisition of high-precision time information by the time acquisition unit is resumed after an interruption; and the vehicle's circumstances and the vehicle's condition The system includes a situation identification unit (140, 140a, 140b) that identifies at least one of the following situations, and the time correction unit changes the correction limit value, which is the upper limit of the correction amount per correction in the time correction unit, according to the situation identified by the situation identification unit. The situation identification unit (140a) identifies whether or not a vehicle can pass through a traffic infrastructure, which switches whether or not a vehicle can pass through the traffic infrastructure, as a situation, and the time correction unit (150a) corrects the internal time by making the correction limit value smaller than when a vehicle cannot pass through the traffic infrastructure, when the situation identification unit identifies that a vehicle can pass through the traffic infrastructure, while when the situation identification unit identifies that a vehicle cannot pass through the traffic infrastructure, it suspends the correction of the internal time until the vehicle stops in that traffic infrastructure, and then corrects the internal time without a correction limit value after the vehicle has stopped. To achieve the above objective, the sixth vehicle time correction device of this disclosure is a vehicle time correction device used in a vehicle that uses internal time for automatic driving control, comprising: a time acquisition unit (110) that sequentially acquires high-precision time information, which is more accurate than the internal time, received by communication from outside the vehicle; a time synchronization control unit (130) that sequentially synchronizes the internal time to the high-precision time based on the high-precision time information acquired sequentially by the time acquisition unit; a time control unit (120) that autonomously compensates for the internal time in the vehicle when the acquisition of high-precision time information by the time acquisition unit is interrupted; and a time correction unit (120) that corrects the difference between the high-precision time and the internal time compensated by the time control unit when the acquisition of high-precision time information by the time acquisition unit is resumed after an interruption. The system comprises (50, 150a, 150b, 150c, 150d) and a situation identification unit (140, 140a, 140b) that identifies at least one of the situations in which the vehicle is located and the situation of the vehicle itself. The time correction unit changes the correction upper limit, which is the upper limit of the correction amount per correction in the time correction unit, according to the situation identified by the situation identification unit. The situation identification unit identifies the distance between the vehicle and at least one of the target vehicles, which is either a preceding vehicle or a following vehicle. The time correction unit corrects the internal time by decreasing the correction upper limit as the distance between vehicles identified by the situation identification unit decreases, and corrects the internal time by increasing the correction upper limit as the distance between vehicles identified by the situation identification unit increases. To achieve the above objective, the seventh vehicle time correction device of this disclosure is a vehicle time correction device used in a vehicle that uses internal time for automatic driving control, comprising: a time acquisition unit (110) that sequentially acquires high-precision time information, which is more accurate than the internal time, received by communication from outside the vehicle; a time synchronization control unit (130) that sequentially synchronizes the internal time to the high-precision time based on the high-precision time information acquired sequentially by the time acquisition unit; a time control unit (120) that autonomously compensates for the internal time in the vehicle when the acquisition of high-precision time information by the time acquisition unit is interrupted; and a time correction unit (150, 150a, 150b, 150c) that corrects the difference between the high-precision time and the internal time compensated by the time control unit when the acquisition of high-precision time information by the time acquisition unit is resumed after an interruption. The time correction unit comprises a 150d) and a situation identification unit (140, 140a, 140b) that identifies at least one of the situations in which the vehicle is located and the situation of the vehicle itself. The time correction unit changes the correction limit value, which is the upper limit of the correction amount per correction in the time correction unit, according to the situation identified by the situation identification unit. The situation identification unit identifies whether the vehicle is in remote-controlled automatic driving mode and whether there is a malfunction in the surrounding monitoring sensor used for monitoring the vehicle's surroundings. When the situation identification unit identifies that the vehicle is in remote-controlled automatic driving mode and there is a malfunction in the surrounding monitoring sensor, the time correction unit corrects the internal time by increasing the correction limit value compared to when the situation identification unit identifies that the vehicle is not in remote-controlled automatic driving mode or there is no malfunction in the surrounding monitoring sensor.

[0008] According to this, when the acquisition of high-precision time information, which is more accurate than the internal time, is interrupted, the difference between the internal time, which the vehicle autonomously compensates for, and the high-precision time can be corrected when the acquisition is resumed after the interruption. In this case, the upper limit of the correction amount per correction can be changed depending on at least one of the conditions in which the vehicle is located and the condition of the vehicle itself. Therefore, in situations where it is desirable to keep the correction amount per correction small, the upper limit of the correction amount can be reduced, making it possible to keep the correction amount per correction small. Also, in situations where it is not necessary to keep the correction amount per correction small or where it is desirable to increase it, the upper limit of the correction amount can be increased, making it possible to increase the correction amount per correction. As a result, even when it is necessary to significantly correct the internal time in a vehicle that uses the internal time for autonomous driving control, it becomes less likely for the occupants to notice any malfunction. [Brief explanation of the drawing]

[0009] [Figure 1] This figure shows an example of a schematic configuration of vehicle system 1. [Figure 2] This figure shows an example of a schematic configuration of the time synchronization device 10. [Figure 3] This diagram illustrates an example of performing the necessary internal time correction in a single correction. [Figure 4] This diagram illustrates an example of performing internal time corrections in multiple steps, while keeping the amount of correction per correction small. [Figure 5] This diagram illustrates an example of performing internal time corrections in multiple steps, while keeping the amount of correction per correction small. [Figure 6] This flowchart shows an example of the time correction-related processing flow in the time synchronization device 10. [Figure 7] This figure shows an example of a schematic configuration of the vehicle system 1a. [Figure 8] This figure shows an example of a schematic configuration of the time synchronization device 10a. [Figure 9] It is a diagram showing an example of a schematic configuration of a vehicle system 1b. [Figure 10] It is a diagram showing an example of a schematic configuration of a time synchronization device 10b. [Figure 11] It is a diagram showing an example of a schematic configuration of a vehicle system 1c. [Figure 12] It is a diagram showing an example of a schematic configuration of a time synchronization device 10c. [Figure 13] It is a flowchart showing an example of the flow of time correction related processing in the time synchronization device 10c. [Figure 14] It is a diagram showing an example of a schematic configuration of a vehicle system 1d. [Figure 15] It is a diagram showing an example of a schematic configuration of a time synchronization device 10d. [Figure 16] It is a flowchart showing an example of the flow of time correction related processing in the time synchronization device 10d.

Embodiments for Carrying Out the Invention

[0010] While referring to the drawings, a plurality of embodiments for disclosure will be described. For the sake of convenience of explanation, among the plurality of embodiments, parts having the same functions as those shown in the drawings used in the previous explanations may be denoted by the same reference numerals, and the explanations thereof may be omitted. For parts denoted by the same reference numerals, the explanations in other embodiments can be referred to.

[0011] (Embodiment 1) <Schematic Configuration of Vehicle System 1> Hereinafter, Embodiment 1 of the present disclosure will be described with reference to the drawings. The vehicle system 1 shown in FIG. 1 can be used in a vehicle capable of autonomous driving (hereinafter, an autonomous driving vehicle). The vehicle system 1 shown in FIG. 1 is preferably capable of being used in a vehicle capable of autonomous driving by remote operation (hereinafter, a remotely operated vehicle). The remotely operated vehicle may realize autonomous driving by remote operation by performing vehicle control according to a remote operation command value transmitted from a remote operation center.

[0012] As shown in Figure 1, the vehicle system 1 includes a time synchronization device 10, a communication module 11, a locator 12, a map database (hereinafter referred to as map DB) 13, a vehicle status sensor 14, a surrounding monitoring sensor 15, a vehicle control ECU 16, and an autonomous driving ECU 17. These should be configured to be connected to the in-vehicle LAN (see LAN in Figure 1). The vehicle using the vehicle system 1 is not necessarily limited to automobiles, but the following explanation will use the case of use in an automobile as an example.

[0013] The degree of automation in autonomous vehicles (hereinafter referred to as the automation level) can be divided into multiple levels, as defined by, for example, the SAE. The automation levels are classified into LV0 to LV5, as follows:

[0014] LV0 is the level where the driver performs all driving tasks without system intervention. Driving tasks can also be called dynamic driving tasks. Driving tasks include, for example, steering, acceleration / deceleration, and surrounding area monitoring. LV0 corresponds to so-called manual driving. LV1 is the level where the system assists with either steering or acceleration / deceleration. LV1 corresponds to so-called driver assistance. LV2 is the level where the system assists with both steering and acceleration / deceleration. LV2 corresponds to so-called partial driving automation. LV1 and LV2 are also considered part of automated driving.

[0015] For example, Levels 1 and 2 of autonomous driving are autonomous driving systems where the driver has a duty to monitor safe driving (hereinafter simply referred to as the "duty to monitor"). This duty includes visually monitoring the surroundings. Level 3 autonomous driving is a level where the system can perform all driving tasks under specific conditions, and the driver takes over driving operations in emergencies. In Level 3 autonomous driving, the driver is required to be able to respond quickly when the system requests a driver change. Level 3 corresponds to so-called conditional driving automation.

[0016] Level 4 autonomous driving is a level where the system can perform all driving tasks except in specific situations such as unsuitable roads or extreme environments. Level 4 corresponds to so-called advanced driving automation. Level 5 autonomous driving is a level where the system can perform all driving tasks in all environments. Level 5 corresponds to so-called fully automated driving. For example, autonomous driving at levels 3 to 5 is autonomous driving where the driver has no duty to monitor. In other words, it is autonomous driving without monitoring duty. Among autonomous driving at levels 3 to 5, autonomous driving at level 4 and above is autonomous driving where the driver is permitted to sleep. In other words, it is autonomous driving that allows sleep.

[0017] The autonomous vehicle in this embodiment shall have a switchable automation level. The automation level may be configured to be switchable only between some of the levels from LV0 to LV5. However, the autonomous vehicle using vehicle system 1 may have a fixed automation level.

[0018] The communication module 11 transmits and receives information via wireless communication with an external center of the vehicle. In other words, it performs wide-area communication. The communication module 11 receives information distributed from the center via wide-area communication. The communication module 11 may also transmit and receive information via wireless communication with other vehicles. In other words, it may perform vehicle-to-vehicle communication. The communication module 11 may also transmit and receive information via wireless communication with a roadside unit installed on the roadside. In other words, it may perform vehicle-to-infrastructure communication. When performing vehicle-to-infrastructure communication, the communication module 11 may receive information about surrounding vehicles transmitted from surrounding vehicles via the roadside unit. The communication module 11 may also receive information about surrounding vehicles transmitted from surrounding vehicles via wide-area communication through the center.

[0019] The communication module 11 receives remote control command values ​​when they are transmitted from the remote control center. The remote control center is a center for remotely controlling autonomous vehicles.

[0020] The locator 12 is equipped with a GNSS (Global Navigation Satellite System) receiver and an inertial sensor. The GNSS receiver receives positioning signals from multiple positioning satellites. The inertial sensor includes, for example, a gyroscope and an accelerometer. The locator 12 sequentially determines the vehicle position of the vehicle equipped with the locator 12 (hereinafter referred to as "vehicle position") by combining the positioning signals received by the GNSS receiver with the measurement results from the inertial sensor. The vehicle position can be represented, for example, by latitude and longitude coordinates. In addition, the vehicle position may also be determined using the distance traveled, which is obtained from signals sequentially output from the vehicle speed sensor described later. When the locator 12 receives positioning signals, it also receives time information from the positioning satellites included in the positioning signals. This time information is, for example, time information generated by an atomic clock. This time information can be rephrased as absolute time information. Furthermore, this time information is more accurate than the internal time generated by the time synchronization device 10. In other words, it corresponds to high-precision time information. In the following, the time information received by a GNSS receiver from a positioning satellite will be referred to as absolute time information.

[0021] Map DB13 is a non-volatile memory that stores high-precision map data. This high-precision map data is more accurate than the map data used for route guidance in the navigation function. Map DB13 also stores the map data used for route guidance (hereinafter referred to as route guidance map data).

[0022] High-precision map data includes information usable for autonomous driving, such as three-dimensional road shape information, lane count information, and information indicating the permitted direction of travel for each lane. In addition, high-precision map data may also include information on node points indicating the positions of both ends of road markings, such as lane markings.

[0023] Route guidance map data stores map data such as link data and node data. Link data consists of data such as the link ID, which is a unique number that identifies the link; the link length, which indicates the length of the link; the link direction; the shape information of the link; the node coordinates of the start and end points of the link; and road attributes. Road attributes include road name, road type, road width, and speed limit values. On the other hand, node data consists of data such as the node ID, which is a unique number assigned to each node on the map; node coordinates; node name; node type; connection link ID, which describes the link ID of the link connected to the node; and intersection type.

[0024] Alternatively, map data distributed from an external server may be received via wide-area communication through the communication module 11 and stored in the map DB 13. In this case, the map DB 13 may be configured as volatile memory, and the communication module 11 may sequentially acquire map data for the area corresponding to the vehicle's position.

[0025] The vehicle condition sensor 14 is a group of sensors for detecting various states of the vehicle. Examples of vehicle condition sensors 14 include a vehicle speed sensor. The vehicle speed sensor outputs a vehicle speed pulse. The vehicle condition sensor 14 outputs the detected sensing information to the in-vehicle LAN. Alternatively, the sensing information detected by the vehicle condition sensor 14 may be output to the in-vehicle LAN via an ECU installed in the vehicle.

[0026] The surrounding monitoring sensor 15 monitors the environment around the vehicle. For example, the surrounding monitoring sensor 15 detects obstacles around the vehicle, such as moving objects like pedestrians and other vehicles, and stationary objects like objects that have fallen on the road. It also detects road markings such as lane markings around the vehicle. The surrounding monitoring sensor 15 may be, for example, a surrounding monitoring camera that images a predetermined range around the vehicle, or a sensor such as a millimeter-wave radar, sonar, or LiDAR that transmits detection waves to a predetermined range around the vehicle. The surrounding monitoring camera sequentially outputs the captured images as sensing information to the autonomous driving ECU 17. Sensors that transmit detection waves, such as sonar, millimeter-wave radar, or LiDAR, sequentially output the scanning results based on the received signals obtained when they receive reflected waves reflected by obstacles as sensing information to the autonomous driving ECU 17. The sensing information detected by the surrounding monitoring sensor 15 may be configured to be output to the autonomous driving ECU 17 without going through the in-vehicle LAN.

[0027] The vehicle control ECU16 is an electronic control unit that controls the vehicle's movement. Movement control includes acceleration / deceleration control and / or steering control. The vehicle control ECU16 includes components such as a steering ECU for steering control, a power unit control ECU for acceleration / deceleration control, and a brake ECU. The vehicle control ECU16 controls the vehicle's movement by outputting control signals to various movement control devices installed in the vehicle, such as the electronically controlled throttle, brake actuator, and EPS (Electric Power Steering) motor.

[0028] The autonomous driving ECU 17 includes, for example, a processor, memory, I / O, and a bus connecting them, and performs autonomous driving-related processing by executing a control program stored in memory. The memory referred to here is a non-transitory tangible storage medium that non-temporarily stores programs and data that can be read by a computer. The non-transitory tangible storage medium is implemented by semiconductor memory or magnetic disks, etc. The autonomous driving ECU 17 includes a driving environment recognition unit, an action decision unit, and a control execution unit as functional blocks.

[0029] The driving environment recognition unit recognizes the vehicle's driving environment from the vehicle's position obtained from the locator 12, map data obtained from the map DB 13, and sensing information obtained from the surrounding monitoring sensor 15. For example, the driving environment recognition unit uses this information to recognize the position, shape, and movement of objects around the vehicle and generates a virtual space that reproduces the actual driving environment. The driving environment recognition unit only needs to recognize the vehicle's position on the map from the vehicle's position and map data. If the driving environment recognition unit can obtain position information, speed information, etc., of surrounding vehicles, etc., via the communication module 11, it should also use this information to recognize the driving environment.

[0030] The action decision unit switches the control authority for driving operations between the driver and the vehicle's system. When the control authority for driving operations is with the system, the action decision unit determines a driving plan for the vehicle based on the driving environment recognition results from the driving environment recognition unit. Two types of driving plans are generated: a long- and medium-term driving plan and a short-term driving plan.

[0031] In long- and medium-term driving plans, a route is generated to guide the vehicle to a set destination. This route consists of multiple links. The autonomous driving ECU17 should generate this route in the same way as the route search for the navigation function. This route search can be performed, for example, by cost calculation using Dijkstra's algorithm. In cost calculation using Dijkstra's algorithm, the link costs of links that satisfy search conditions such as distance priority and time priority are set to be small. Then, the route with the smallest link cost value is searched for as the recommended route.

[0032] The action decision unit, in the short-term driving plan, uses the generated virtual space around the vehicle to generate a planned driving trajectory that will allow the vehicle to drive according to the long-term driving plan. In the short-term driving plan, it decides to perform actions such as steering for lane changes, acceleration and deceleration for speed adjustment, and steering and braking for obstacle avoidance.

[0033] When the control execution unit has control over the driving operation, it works in cooperation with the vehicle control ECU 16 to perform acceleration / deceleration control and steering control of the vehicle according to the driving plan determined by the action decision unit. These vehicle controls in autonomous driving correspond to autonomous driving control.

[0034] When the vehicle performs remote autonomous driving, the autonomous driving ECU 17 only needs to transmit the driving environment recognized by the driving environment recognition unit to the remote control center via the communication module 11. In this case, the remote control center determines a driving plan based on the received driving environment, in the same manner as the action decision unit. When the vehicle performs remote autonomous driving, the control execution unit obtains remote control command values ​​from the remote control center via the communication module 11. The control execution unit then executes acceleration / deceleration control and steering control of the vehicle according to the obtained remote control command values. The remote control command values ​​are command values ​​for steering, acceleration, deceleration, etc., linked to absolute time. These vehicle controls in remote autonomous driving also correspond to autonomous driving control.

[0035] The time synchronization device 10 is primarily composed of a computer equipped with a processor, volatile memory, non-volatile memory, I / O, and a bus connecting these. The time synchronization device 10 performs time synchronization processing by executing a control program stored in the non-volatile memory. In the synchronization-related processing, the internal time of the vehicle's system is synchronized with the absolute time. The internal time of the vehicle's system is used for automatic driving control. This time synchronization device 10 corresponds to a vehicle time correction device. The configuration of the time synchronization device 10 will be described in detail below.

[0036] <Outline configuration of time synchronization device 10> Next, the schematic configuration of the time synchronization device 10 will be explained using Figure 2. As shown in Figure 2, the time synchronization device 10 includes a time acquisition unit 110, a time control unit 120, a time synchronization control unit 130, a status identification unit 140, a time correction unit 150, and a time output unit 160 as functional blocks. Some or all of the functions performed by the time synchronization device 10 may be configured in hardware using one or more ICs, etc. Also, some or all of the functional blocks of the time synchronization device 10 may be realized by a combination of software execution by a processor and hardware components.

[0037] The time acquisition unit 110 acquires absolute time information received from the positioning satellite by the locator 12. Each time the time acquisition unit 110 receives absolute time information from the locator 12, it acquires the received absolute time information from the locator 12. For example, the transmission of absolute time from the positioning satellite can be set to a 1-second period.

[0038] The time control unit 120 measures the time by counting the internal clock of the time synchronization device 10. The time control unit 120 then generates the measured time as the internal time. The accuracy of the internal time is assumed to be lower than that of the absolute time. For example, the generation of the internal time can be set to a period of 100 msec.

[0039] The time synchronization control unit 130 sequentially synchronizes the internal time generated by the time control unit 120 with the absolute time information sequentially acquired by the time acquisition unit 110. The time synchronization control unit 130 synchronizes the internal time with the absolute time when it acquires absolute time information from the time acquisition unit 110. In other words, the time synchronization control unit 130 synchronizes the internal time with the absolute time when it receives absolute time information from a positioning satellite with the GNSS receiver. Hereafter, synchronizing the internal time with the absolute time will be referred to as time synchronization.

[0040] The time control unit 120 autonomously compensates for the vehicle's internal time after time synchronization is performed and until the time acquisition unit 110 acquires new absolute time information. In other words, it uses the synchronized internal time as a reference and treats the time counted by the internal clock as the internal time. The time control unit 120 also autonomously compensates for the vehicle's internal time if the acquisition of absolute time information by the time acquisition unit 110 is interrupted. Interruption of absolute time information acquisition refers to a situation where the acquisition interval of absolute time information becomes longer than the transmission period of absolute time information from positioning satellites. Situations in which the acquisition of absolute time information is interrupted include when the vehicle enters a tunnel or similar and is unable to receive positioning signals from positioning satellites. Another example is when the vehicle is parked for a long time in an underground parking lot and is unable to receive positioning signals from positioning satellites. The longer the situation in which the acquisition of absolute time information is interrupted lasts, the lower the accuracy of the internal time that the vehicle autonomously compensates for. In other words, the difference between the absolute time and the internal time becomes larger. In the following, the interruption of obtaining absolute time information will be referred to as a time acquisition interruption.

[0041] The situation identification unit 140 identifies at least one of the situations in which the vehicle is located and the situation of the vehicle itself. The situation identification unit 140 can identify whether the vehicle is in remote-controlled autonomous driving mode or not as a situation. The situation identification unit 140 can identify whether the vehicle is in remote-controlled autonomous driving mode or not by monitoring the autonomous driving ECU 17. The situation identification unit 140 can identify the vehicle speed as a situation. The situation identification unit 140 can identify the vehicle speed from the sensing results of the vehicle condition sensor 14.

[0042] The situation identification unit 140 should identify the predicted behavior of the vehicle in autonomous driving control as a situation. The predicted behavior of the vehicle in autonomous driving control will be referred to as predicted behavior below. The situation identification unit 140 should identify the predicted behavior from the driving plan determined by the action decision unit of the autonomous driving ECU 17. The situation identification unit 140 should identify the shape of the vehicle's driving path as a situation. The situation identification unit 140 should identify the shape of the vehicle's driving path from the driving environment recognized by the driving environment recognition unit of the autonomous driving ECU 17. The situation identification unit 140 should identify whether it is a straight road or a curved road. The situation identification unit 140 should identify a section of the driving path with a curvature greater than or equal to a specified value as a curved road. The specified value can be any value that can be set arbitrarily.

[0043] The situation identification unit 140 only needs to identify the distance between the vehicle and at least one of the target vehicles, either a preceding vehicle or a following vehicle, as the situation. This distance will be referred to as the target distance below. The situation identification unit 140 only needs to identify the target distance from the driving environment recognized by the driving environment recognition unit of the autonomous driving ECU 17. The situation identification unit 140 only needs to identify whether or not there is a malfunction in the surrounding monitoring sensor 15 as the situation. The situation identification unit 140 only needs to identify whether or not there is a malfunction in the surrounding monitoring sensor 15 from the recognition results of the driving environment recognition unit of the autonomous driving ECU 17. For example, if the recognition of the driving environment fails, it can be identified that there is a malfunction in the surrounding monitoring sensor 15.

[0044] The time correction unit 150 corrects the difference between the absolute time and the internal time that was interpolated by the time control unit 120 when the acquisition of absolute time information is resumed after time acquisition has been interrupted. This difference between the absolute time and the interpolated internal time is referred to below as the required correction amount. The time correction unit 150 changes the correction upper limit value according to the situation identified by the situation identification unit 140. The correction upper limit value is the upper limit of the correction amount per correction by the time correction unit 150. If the required correction amount is less than or equal to the correction upper limit value, the time correction unit 150 corrects the internal time by the required correction amount in a single correction. On the other hand, if the required correction amount exceeds the correction upper limit value, the time correction unit 150 sets the correction amount so that the correction amount in a single correction falls within the correction upper limit value. For example, the correction amount for multiple corrections can be set so that the correction amount per correction is equal. Then, the correction amount per correction is set to the set correction amount, and the internal time is corrected in multiple steps.

[0045] With the above configuration, it becomes possible to keep the amount of correction per correction small in situations where it is desirable to keep it small. Also, it becomes possible to increase the amount of correction per correction in situations where it is not necessary to keep it small or where it is desirable to increase it. As a result, in vehicles that use internal time for autonomous driving control, even when it is necessary to significantly correct the internal time, it becomes possible to make it less likely for the occupants to notice any malfunction.

[0046] Here, we will use Figures 3 to 5 to further explain the effects of this embodiment. Here, we will explain using the case of remote automatic driving as an example. In the examples of Figures 3 to 5, it is assumed that the difference between the absolute time and the internal time has become large due to the interruption of time acquisition. Figure 3 is a diagram illustrating an example in which the internal time is corrected by the required correction amount in a single correction. Figures 4 and 5 are diagrams illustrating an example in which the amount of correction per correction is reduced and the internal time is corrected in multiple steps. Figure 4 is an example in which the internal time is corrected so that the time corrected each time is equal. Figure 5 is an example in which the internal time is corrected so that the amount of change in the command value each time is equal. The vertical axis in Figures 3 to 5 represents the command value. As mentioned above, the command value is the command value for steering, acceleration, deceleration, etc. The horizontal axis in Figures 3 to 5 represents time. The dotted lines in Figures 3 to 5 represent the command value from the remote control center. The bold solid lines in Figures 3 to 5 represent the actual command value to the vehicle. The double arrows in Figures 3 to 5 indicate the time delay between the command value from the remote control center and the actual command value sent to the vehicle.

[0047] As shown in Figure 3, when the internal time is corrected by the required amount in a single correction, the change in the command value becomes large. In this case, the vehicle behavior changes abruptly, making it more likely for the occupants to notice a malfunction. On the other hand, as shown in Figures 4 and 5, when the internal time is corrected in multiple steps, the change in the command value becomes smaller. In this case, the vehicle behavior is less likely to change abruptly, making it less likely for the occupants to notice a malfunction. Examples of cases where the internal time is corrected in multiple steps are as follows: As shown in Figure 4, the internal time may be corrected so that the time corrected in each step is equal. As shown in Figure 5, the internal time may be corrected so that the change in the command value in each step is equal. In both cases, Figure 4 and Figure 5, the amount of internal time correction in each step is set to stay within the correction upper limit.

[0048] It is preferable for the time correction unit 150 to correct the internal time by reducing the correction upper limit based on the status identification unit 140's determination that the vehicle is in remote-controlled automatic driving mode. In this case, the time correction unit 150 should correct the internal time by reducing the correction upper limit compared to when the status identification unit 140 determines that the vehicle is not in remote-controlled automatic driving mode. If the amount of internal time correction becomes too large during remote-controlled automatic driving, the remote control command value may change rapidly, potentially causing abrupt changes in vehicle behavior. In contrast, reducing the correction upper limit during remote-controlled automatic driving makes it possible to suppress abrupt changes in vehicle behavior.

[0049] It is preferable for the time correction unit 150 to correct the internal time by decreasing the correction upper limit in accordance with the vehicle speed of the vehicle identified by the situation identification unit 140 as it increases. It is also preferable for the time correction unit 150 to correct the internal time by increasing the correction upper limit in accordance with the vehicle speed of the vehicle identified by the situation identification unit 140 as it decreases. The faster the vehicle speed, the greater the position error due to the correction of the internal time. The faster the position error, the lower the accuracy of automated driving using a high-precision map, so it is preferable to keep the position error small. In contrast to this, the above configuration decreases the correction upper limit in accordance with the vehicle speed of the vehicle. Therefore, it becomes possible to keep the position error small. On the other hand, the slower the vehicle speed, the smaller the position error becomes even if the correction amount per instance is large. In contrast to this, the above configuration increases the correction upper limit in accordance with the vehicle speed of the vehicle. Therefore, in situations where the position error can be kept small, it becomes possible to increase the correction amount and quickly correct the internal time.

[0050] For example, if the required correction amount is 30 msec, correcting it all at once would result in a position error of approximately 0.8 m when the vehicle is traveling at 100 km / h. If the correction limit is set to 5 msec, the correction would need to be divided into 6 steps. However, the position error for each correction would be only about 0.15 m. The correction limit should be set according to this tolerance for position error. The relationship between vehicle speed and the correction limit can be expressed using a linear function, exponential function, etc. The relationship between vehicle speed and the correction limit can also be represented using a map.

[0051] Preferably, the time correction unit 150, when the situation identification unit 140 identifies a predetermined predicted behavior, suspends correction of the internal time until the actual behavior of the vehicle reaches that predicted behavior. Then, preferably, the time correction unit 150 performs correction of the internal time without an upper limit on the correction after the actual behavior of the vehicle reaches that predicted behavior. The predetermined predicted behavior is when the vehicle speed of the vehicle falls below a predetermined value within a set time, or when the vehicle comes to a stop within a set time. The set time can be set arbitrarily. Correction of the internal time without an upper limit on the correction means that the necessary amount of correction of the internal time is performed in a single correction. The situation in which the predetermined predicted behavior is reached is a situation in which the position error due to the correction of the internal time is kept small. Therefore, with the above configuration, it becomes possible to wait until a situation in which the position error due to the correction of the internal time is kept small before correcting the internal time.

[0052] The time correction unit 150 preferably corrects the internal time by setting a smaller correction limit than in the case of a straight road when the shape of the vehicle's travel path, as identified by the situation identification unit 140, is a curved road. The time correction unit 150 preferably corrects the internal time by setting a larger correction limit than in the case of a curved road when the shape of the vehicle's travel path, as identified by the situation identification unit 140, is a straight road. When the vehicle's travel path is a curved road, it is preferable to suppress abrupt changes in vehicle behavior. In response to this, the above configuration sets a smaller correction limit when the shape of the vehicle's travel path is a curved road than in the case of a straight road. Therefore, it becomes possible to suppress abrupt changes in vehicle behavior. On the other hand, when the vehicle's travel path is a straight road, abrupt changes in vehicle behavior are more tolerable than in the case of a curved road. In response to this, the above configuration sets a larger correction limit when the vehicle's travel path is a straight road compared to the case of a curved road. Therefore, in situations where abrupt changes in vehicle behavior are more tolerable, it becomes possible to increase the correction amount and quickly correct the internal time.

[0053] It is preferable for the time correction unit 150 to correct the internal time by decreasing the correction upper limit as the distance between target vehicles identified by the situation identification unit 140 decreases. It is preferable for the time correction unit 150 to correct the internal time by increasing the correction upper limit as the distance between target vehicles identified by the situation identification unit 140 increases. As the distance between target vehicles decreases, it is preferable to suppress abrupt changes in the vehicle behavior of the own vehicle. In contrast to this, the above configuration decreases the correction upper limit as the distance between target vehicles decreases. Therefore, it becomes possible to suppress abrupt changes in vehicle behavior. On the other hand, as the distance between target vehicles increases, it is easier to tolerate abrupt changes in the vehicle behavior of the own vehicle. In contrast to this, the above configuration increases the correction upper limit as the distance between target vehicles increases. Therefore, in situations where abrupt changes in vehicle behavior are easily tolerated, it becomes possible to increase the correction amount and quickly correct the internal time.

[0054] The time correction unit 150 preferably increases the correction upper limit to correct the internal time even when the vehicle is in remote automatic driving mode, if the following condition is met. This condition is when the situation identification unit 140 identifies a malfunction in the surrounding monitoring sensor 15. Here, the correction upper limit should be greater than when the vehicle is not in remote automatic driving mode and when the situation identification unit 140 identifies no malfunction in the surrounding monitoring sensor 15. When there is a malfunction in the surrounding monitoring sensor 15, it becomes more difficult for the vehicle to autonomously avoid obstacles. Therefore, it is preferable to correct the internal time more quickly and perform remote automatic driving according to the remote operation command value. With the above configuration, even when the vehicle is in remote automatic driving mode, it becomes possible to correct the internal time more quickly in situations where it is preferable to correct the internal time more quickly.

[0055] Furthermore, the time correction unit 150 may be configured not to correct the internal time according to the situation identified by the situation identification unit 140 if the required correction amount is less than the set value. In this case, the time synchronization control unit 130 can synchronize the internal time to the absolute time based on the absolute time information acquired by the time acquisition unit 110. The set value referred to here can be any value that can be set arbitrarily. This reduces the waste of correcting the internal time according to the situation identified by the situation identification unit 140 when the required correction amount is sufficiently small.

[0056] The time output unit 160 outputs the internal time used for automatic driving control. If neither interpolation by the time control unit 120 nor correction by the time correction unit 150 is performed, the time output unit 160 should output the internal time synchronized by the time synchronization control unit 130. If interpolation is performed by the time control unit 120 but correction is not performed by the time correction unit 150, the time output unit 160 should output the internal time after the interpolation is performed. If correction is performed by the time correction unit 150, the time output unit 160 should output the internal time after the correction is performed.

[0057] <Time correction related processing in the time synchronization device 10> Here, using the flowchart in Figure 6, an example of the flow of processing related to the correction of the internal time in the time synchronization device 10 (hereinafter referred to as "time correction-related processing") will be explained. The flowchart in Figure 6 should be configured to start when absolute time information is received by the locator 12 after time acquisition has been interrupted. In addition, if the system can switch the automatic driving function on and off, the condition that the automatic driving function is turned on may also be added.

[0058] First, in step S1, the time acquisition unit 110 acquires absolute time information received from positioning satellites by the locator 12. In step S2, the time control unit 120 generates the internal time. Here, the time control unit 120 generates the internal time that was autonomously supplemented when time acquisition was interrupted.

[0059] In step S3, the time correction unit 150 identifies the required correction amount, which is the difference between the absolute time obtained in S1 and the internal time generated in S2. In step S4, the situation identification unit 140 identifies at least one of the situations in which the vehicle is located and the situation of the vehicle itself.

[0060] In step S5, if the situation identified in S4 is one in which the correction of the internal time should be postponed (YES in S5), the process moves to step S6. An example of a situation in which the correction of the internal time should be postponed is when the situation identification unit 140 identifies the predetermined predicted behavior described above. On the other hand, if the situation identified in S4 is not one in which the correction of the internal time should be postponed (NO in S5), the process moves to step S7. Hereafter, the postponement of the correction of the internal time will be referred to as "correction postponement."

[0061] In step S6, if it is time to release the correction hold (YES in S6), the process proceeds to step S7. One possible timing for releasing the correction hold is when the vehicle comes to a stop. The timing for releasing the correction hold may also be when the vehicle speed falls below a predetermined value. The timing for releasing the correction hold can be determined by the time correction unit 150. The time correction unit 150 can determine the timing for releasing the correction hold from the vehicle speed of the vehicle identified by the situation identification unit 140. On the other hand, if it is not time to release the correction hold (NO in S6), the process in S6 is repeated.

[0062] In step S7, the time correction unit 150 determines whether or not to correct the internal time by dividing the required correction amount identified in S3. In S7, the correction upper limit value is changed according to the situation identified in S4. If multiple conditions are used as conditions for changing the correction upper limit value, the correction upper limit value should be raised or lowered according to the number of conditions that are met. For example, the correction condition value can be raised or lowered by multiplying by a coefficient. Examples of conditions for changing the correction upper limit value are as described above. If the required correction amount is less than or equal to the correction upper limit value, the time correction unit 150 decides to correct the internal time without dividing the required correction amount. On the other hand, if the required correction amount exceeds the correction upper limit value, the time correction unit 150 decides to correct the internal time by dividing the required correction amount. If the decision to correct the internal time by dividing the required correction amount is made in S7 (YES in S7), the process moves to step S9. On the other hand, if the decision to correct the internal time without dividing the required correction amount is made in S7 (NO in S7), the process moves to step S8.

[0063] In step S8, the time correction unit 150 sets the required correction amount identified in S3 as the correction amount for one instance. In other words, the correction amount for one correction is set to the required correction amount identified in S3. Then, the process moves to step S10. In step S9, the time correction unit 150 sets the correction amount for one instance when the required correction amount identified in S3 is divided and corrected. Then, the process moves to step S10. The time correction unit 150 should set the correction amount for one instance so that the correction amount per unit of time is equal. The time correction unit 150 should set the correction amount for one instance so that the control amount of automatic operation per unit of time is equal. In this case, the correction amounts for each instance do not need to be equal.

[0064] In step S10, the internal time is corrected using the correction amount set in S8 or S9. If the internal time is corrected using the correction amount set in S8, the required amount of internal time correction will be performed in a single correction. If the internal time is corrected using the correction amount set in S9, the required amount of internal time correction will be performed in multiple corrections.

[0065] In step S11, if the internal time correction is complete (YES in S11), the time correction-related processing is terminated. On the other hand, if the internal time correction is not complete (NO in S11), the process returns to S10 and is repeated. If the internal time correction is to be performed by the required amount through multiple corrections, the process will be repeated the same number of times as the correction is divided.

[0066] (Embodiment 2) The configuration is not limited to Embodiment 1; a configuration like Embodiment 2 described below may also be used. Below, an example of Embodiment 2 will be explained with reference to a diagram.

[0067] <Outline configuration of vehicle system 1a> Hereinafter, Embodiment 2 of this disclosure will be described with reference to the drawings. The vehicle system 1a shown in Figure 7 can be used in the aforementioned autonomous vehicle. Preferably, the vehicle system 1a shown in Figure 7 can be used in the aforementioned remotely driven vehicle.

[0068] As shown in Figure 1, the vehicle system 1a includes a time synchronization device 10a, a communication module 11a, a locator 12, a map DB 13, a vehicle status sensor 14, a surrounding monitoring sensor 15, a vehicle control ECU 16, and an autonomous driving ECU 17a. The vehicle system 1a includes a communication module 11a instead of a communication module 11. The vehicle system 1a includes a time synchronization device 10a instead of a time synchronization device 10. The vehicle system 1a includes an autonomous driving ECU 17a instead of an autonomous driving ECU 17. Except for these points, the vehicle system 1a is the same as the vehicle system 1 of Embodiment 1.

[0069] Communication module 11a is the same as communication module 11 of Embodiment 1, except that some processing differs. These differences will be explained below. Communication module 11a receives information transmitted from the traffic infrastructure management center. The traffic infrastructure management center will be simply referred to as the management center below. The information transmitted from the management center only needs to be information that can identify whether or not a vehicle is allowed to pass through the traffic infrastructure (hereinafter referred to as traffic-related information).

[0070] Traffic-related information transmitted from the management center includes signal control information for traffic lights. In this case, the traffic lights correspond to traffic infrastructure that switches whether or not vehicles are allowed to pass. Signal control information includes information such as the state of the traffic light's color, the display order of the colors, the cycle length of one signal cycle, the ratio of time allocated to each color in one cycle, and the remaining scheduled seconds. Signal control information is linked to absolute time, which will be described later. Note that traffic-related information transmitted from the management center may not be signal control information. For example, it may be information that can identify the timing of opening and closing of railway crossings. In this case, the railway crossing corresponds to traffic infrastructure that switches whether or not vehicles are allowed to pass.

[0071] The autonomous driving ECU 17a is the same as the autonomous driving ECU 17 of Embodiment 1, except that some processing differs. These differences are described below. The action decision unit of the autonomous driving ECU 17a determines whether or not it is permissible to pass through the traffic infrastructure when it receives traffic-related information from the management center via the communication module 11a. Absolute time is associated with the traffic-related information. The communication module 11a may also receive and use traffic-related information when it is transmitted from the traffic infrastructure. The action decision unit also acquires absolute time information received from positioning satellites via the locator 12. This allows the action decision unit to determine the timing of whether or not it is permissible to pass through the traffic infrastructure based on the absolute time. Then, it determines whether or not it is permissible to pass through the traffic infrastructure based on this timing and the estimated arrival time of the vehicle to the traffic infrastructure from the driving plan. If time acquisition is interrupted, the action decision unit can determine whether or not it is permissible to pass through the traffic infrastructure using the absolute time that was received from the positioning satellite after the time acquisition interruption. The decision-making unit determines a driving plan to pass through the traffic infrastructure if it determines that it is passable. On the other hand, if the decision-making unit determines that it is impossible to pass through the traffic infrastructure, it determines a driving plan to stop before reaching the traffic infrastructure. In the driving plan, it is sufficient to decide to remain stopped until it is determined that the traffic infrastructure is passable.

[0072] If the traffic infrastructure is a traffic light, the following should be done: The action decision unit should determine that the traffic light is passable if the vehicle is scheduled to arrive at the traffic light during the green light period. On the other hand, if the vehicle is scheduled to arrive at the traffic light during any other light period, the action decision unit should determine that the traffic light is impassable. The other light periods may be the red and yellow light periods. Depending on the time of day, the traffic light may also be determined to be passable if the vehicle is scheduled to arrive at the traffic light during the flashing red or yellow light period. If the traffic infrastructure is a level crossing, the level crossing should be determined to be passable if the vehicle is scheduled to arrive at the level crossing during the period when the barrier is open. On the other hand, if the vehicle is scheduled to arrive at the level crossing during the period when the barrier is closed, the action decision unit should determine that the level crossing is impassable. The remote control center may determine whether the traffic infrastructure is passable and decide on the driving plan in the same way as the action decision unit described above.

[0073] <Outline configuration of time synchronization device 10a> Next, the schematic configuration of the time synchronization device 10a will be explained using Figure 8. As shown in Figure 2, the time synchronization device 10 includes a time acquisition unit 110, a time control unit 120, a time synchronization control unit 130, a status identification unit 140a, a time correction unit 150a, and a time output unit 160 as functional blocks. The time synchronization device 10a includes a status identification unit 140a instead of the status identification unit 140. The time synchronization device 10a includes a time correction unit 150a instead of the time correction unit 150. Except for these points, the time synchronization device 10a is the same as the time synchronization device 10 of Embodiment 1. This time synchronization device 10a also corresponds to a vehicle time correction device.

[0074] The situation identification unit 140a is the same as the situation identification unit 140 of Embodiment 1, except that some processing differs. The differences will be explained below. The situation identification unit 140a identifies whether or not a vehicle can pass through a traffic infrastructure, which switches whether or not a vehicle can pass through, as a situation. The situation identification unit 140a only needs to identify whether or not a vehicle can pass through a traffic infrastructure based on the identification results from the aforementioned action judgment unit.

[0075] The time correction unit 150a is the same as the time correction unit 150 of Embodiment 1, except that some processing differs. These differences are described below. When the situation identification unit 140a determines that passage through the traffic infrastructure is permitted, the time correction unit 150a performs the following correction: The time correction unit 150a corrects the internal time with a smaller correction upper limit than when passage through the traffic infrastructure is not permitted. On the other hand, when the situation identification unit 140a determines that passage through the traffic infrastructure is not permitted, the time correction unit 150a performs the following correction: The time correction unit 150a suspends the correction of the internal time until the vehicle stops in that traffic infrastructure, and then corrects the internal time without a correction upper limit after the vehicle has stopped.

[0076] With the above configuration, when passage through traffic infrastructure is permitted, the amount of correction per correction can be kept small. Therefore, the amount of correction per correction while driving can be kept small. Consequently, even if it is necessary to significantly correct the internal time while driving, it becomes less likely that the occupants will notice any inconvenience. On the other hand, if passage through traffic infrastructure is not permitted, the system waits until the vehicle is stopped at that traffic infrastructure and corrects the internal time without an upper limit on the correction. While stopped, even if the amount of correction per correction is large, it will not affect the vehicle's behavior. Therefore, it becomes possible to quickly correct the internal time at a time when the occupants are less likely to notice any inconvenience.

[0077] Regarding the time correction-related processing in the time synchronization device 10a, for example, it can be done as follows: In the processing of S5, the situation in which the correction of the internal time is suspended should be made to include the case in which the situation identification unit 140a identifies that passage in the traffic infrastructure is not permitted.

[0078] (Embodiment 3) The configuration is not limited to the embodiments described above; a configuration like Embodiment 3 below may also be used. Below, an example of Embodiment 3 will be explained with reference to a diagram.

[0079] <Outline configuration of vehicle system 1b> Hereinafter, Embodiment 3 of this disclosure will be described with reference to the drawings. The vehicle system 1b shown in Figure 9 can be used in the aforementioned autonomous driving vehicle. Preferably, the vehicle system 1b shown in Figure 9 can be used in the aforementioned remote driving vehicle.

[0080] As shown in Figure 9, the vehicle system 1b includes a time synchronization device 10b, a communication module 11a, a locator 12, a map DB 13, a vehicle status sensor 14, a surrounding monitoring sensor 15, a vehicle control ECU 16, and an autonomous driving ECU 17. The vehicle system 1b is the same as the vehicle system 1 of Embodiment 1, except that it includes a time synchronization device 10b instead of a time synchronization device 10.

[0081] <Outline configuration of time synchronization device 10b> Next, the schematic configuration of the time synchronization device 10b will be explained using Figure 10. As shown in Figure 2, the time synchronization device 10b includes a time acquisition unit 110, a time control unit 120, a time synchronization control unit 130, a status identification unit 140b, a time correction unit 150b, and a time output unit 160 as functional blocks. The time synchronization device 10b includes a status identification unit 140b instead of a status identification unit 140. The time synchronization device 10b includes a time correction unit 150b instead of a time correction unit 150. Except for these points, the time synchronization device 10b is the same as the time synchronization device 10 of Embodiment 1. This time synchronization device 10b also corresponds to a vehicle time correction device.

[0082] The situation identification unit 140b is the same as the situation identification unit 140 of Embodiment 1, except that some processing differs. These differences will be explained below. The situation identification unit 140b only needs to identify the planned entry of the vehicle into a curved road where the occurrence of at least one of lateral acceleration and lateral jerk above a threshold is estimated. This curved road will be referred to as the target curved road below. The threshold can be set to an arbitrarily configurable value. The situation identification unit 140b only needs to identify the planned entry into the target curved road based on the curvature of the curved road, the planned vehicle speed on that curved road, and the correspondence between lateral acceleration or lateral jerk. The correspondence can be obtained, for example, from a map. The situation identification unit 140b can obtain the curvature of the curved road from the map DB 13. The situation identification unit 140b can obtain the planned vehicle speed on the curved road from the driving plan determined by the automatic driving ECU 17.

[0083] The time correction unit 150b is the same as the time correction unit 150 of Embodiment 1, except that some processing differs. These differences will be explained below. When the situation identification unit 140b identifies the planned entry into the target curved road, the time correction unit 150b completes the correction of the internal time on the straight road before entering the target curved road. For example, the time correction unit 150b may perform the correction of the internal time on the straight road before entering the target curved road without a correction upper limit. Alternatively, the time correction unit 150b may perform the correction of the internal time with a correction upper limit that can be completed in a predetermined number of attempts before entering the target curved road. In this case, the grace period before entering the target curved road can be estimated from the vehicle speed and the distance to the target curved road.

[0084] If a change in vehicle behavior occurs due to correction of the internal time, the straight road is less likely to cause anxiety to the occupants than the curved road in question. In contrast, with the above configuration, the correction of the internal time is completed on the straight road before entering the curved road in question, thus further reducing the likelihood of anxiety to the occupants. Note that the configuration of Embodiment 3 and the configuration of Embodiment 2 may be combined.

[0085] (Embodiment 4) The configuration is not limited to the embodiments described above; a configuration like Embodiment 4 below may also be used. Below, an example of Embodiment 4 will be explained with reference to a diagram.

[0086] <Outline configuration of vehicle system 1c> Hereinafter, Embodiment 4 of this disclosure will be described with reference to the drawings. The vehicle system 1c shown in Figure 11 can be used in the aforementioned autonomous driving vehicle. Preferably, the vehicle system 1c shown in Figure 11 can be used in the aforementioned remote driving vehicle.

[0087] As shown in Figure 11, the vehicle system 1c includes a time synchronization device 10c, a communication module 11c, a locator 12, a map DB 13, a vehicle status sensor 14, a surrounding monitoring sensor 15, a vehicle control ECU 16, and an autonomous driving ECU 17. The vehicle system 1c includes a time synchronization device 10c instead of a time synchronization device 10. The vehicle system 1c includes a communication module 11c instead of a communication module 11. Except for these points, the vehicle system 1c is the same as the vehicle system 1 of Embodiment 1.

[0088] The communication module 11c is the same as the communication module 11 of Embodiment 1, except that some processing differs. These differences will be explained below. The communication module 11c receives provisional time information from devices other than positioning satellites via communication. The provisional time is less accurate than absolute time, but is more accurate than the internal time generated by the time synchronization device 10c. Examples of devices other than positioning satellites include server equipment at the center, cellular communication base stations, wireless LAN access points, and multifunction mobile phones. Hereinafter, these devices other than positioning satellites will be referred to as external devices. The communication from which the communication module 11c receives provisional time information may be cellular communication or communication compliant with wireless communication standards.

[0089] <Outline configuration of time synchronization device 10c> Next, the schematic configuration of the time synchronization device 10c will be explained using Figure 12. As shown in Figure 12, the time synchronization device 10c comprises a time acquisition unit 110, a time control unit 120, a time synchronization control unit 130, a status identification unit 140, a time correction unit 150c, a time output unit 160, a provisional acquisition unit 170, and an external output unit 180 as functional blocks. The time synchronization device 10c includes a time correction unit 150c instead of a time correction unit 150. The time synchronization device 10c includes a provisional acquisition unit 170 and an external output unit 180. Except for these points, the time synchronization device 10c is the same as the time synchronization device 10 of Embodiment 1. This time synchronization device 10c also corresponds to a vehicle time correction device.

[0090] The provisional time acquisition unit 170 acquires provisional time information from an external device via communication. The provisional time acquisition unit 170 should acquire provisional time information from an external device via the communication module 11c. The provisional time acquisition unit 170 should acquire provisional time information when it receives it from an external device via the communication module 11c. The communication module 11c should receive provisional time information at a time when it is able to communicate with the external device. This timing should be when the vehicle is within the communication range of the external device.

[0091] The time correction unit 150c is the same as the status identification unit 140 of Embodiment 1, except that some processing differs. These differences will be explained below. The time correction unit 150c performs provisional processing when time acquisition is interrupted, but provisional time information can be acquired by the provisional acquisition unit 170. As provisional processing, the time correction unit 150c performs a correction to provisionally synchronize the internal time to the provisional time based on the provisional time information acquired by the provisional acquisition unit 170.

[0092] The provisional time is more accurate than the internal time generated by the time synchronization device 10c. Therefore, by synchronizing the internal time with the provisional time and performing a provisional correction, it is possible to correct the internal time to be more accurate than the internal time generated by the time synchronization device 10c. Consequently, interruptions in time acquisition are eliminated, and when synchronizing the internal time with the absolute time, it becomes possible to keep the amount of correction required for the internal time lower compared to when no provisional correction is performed. As a result, it becomes possible to make the crew less likely to notice the malfunction.

[0093] The external output unit 180 outputs information (hereinafter referred to as "identification information") that can identify whether the internal time is synchronized to absolute time or provisional time to the outside of the vehicle. This external output unit 180 corresponds to the information output unit. The external output unit 180 can, for example, transmit the identification information to a remote control center via a communication module 11c. This makes it possible for the remote control center to issue remote control instructions according to whether the internal time is synchronized to absolute time or provisional time. The destination to which the external output unit 180 outputs the identification information does not have to be the remote control center.

[0094] <Time correction related processing in time synchronization device 10c> Here, using the flowchart in Figure 13, we will explain an example of the flow of time correction-related processing in the time synchronization device 10c. The flowchart in Figure 13 should be configured to start when time acquisition is interrupted. In addition, if the configuration allows switching the automatic driving function on and off, the condition that the automatic driving function is on may also be added.

[0095] First, in step S21, if the locator 12 can receive absolute time information from the positioning satellite (YES in S21), the process moves to step S22. On the other hand, if absolute time information cannot be received (NO in S21), the process moves to step S23. In step S22, the time acquisition unit 110 acquires the absolute time information received by the locator 12 from the positioning satellite, and the process moves to step S25.

[0096] In step S23, if the communication module 11c can receive provisional time information from an external device (YES in S23), the process proceeds to step S24. On the other hand, if provisional time information cannot be received (NO in S23), the process proceeds to step S35. In step S24, the provisional acquisition unit 170 acquires the provisional time information received by the communication module 11c from the external device, and the process proceeds to step S25.

[0097] In step S25, the same processing as in S2 is performed. In step S26, the time correction unit 150c identifies the required correction amount in the same manner as in S3. In S26, if absolute time information was obtained in S22, the required correction amount, which is the difference between the absolute time obtained in S22 and the internal time generated in S25, is identified. In S26, if provisional time information was obtained in S24, the required correction amount, which is the difference between the provisional time obtained in S24 and the internal time generated in S25, is identified.

[0098] Steps S27 to S34 perform the same processing as in S4 to S11. In step S35, if it is the end of the time correction-related processing (YES in S35), the time correction-related processing is terminated. On the other hand, if it is not the end of the time correction-related processing (NO in S35), the process returns to S21 and is repeated. Examples of the end of the time correction-related processing include the vehicle's power switch being turned off or the automatic driving function being turned off. The power switch is a switch used to start the vehicle's internal combustion engine or motor generator. Note that the configuration of Embodiment 4 may be combined with the configurations of Embodiments 2 and 3.

[0099] (Embodiment 5) The configuration is not limited to the embodiments described above; a configuration like Embodiment 5 below may also be used. Below, an example of Embodiment 5 will be explained with reference to a diagram.

[0100] <Outline configuration of vehicle system 1d> Embodiment 5 of this disclosure will be described below with reference to the drawings. The vehicle system 1d shown in Figure 14 can be used in the aforementioned autonomous vehicle. Preferably, the vehicle system 1d shown in Figure 14 can be used in the aforementioned remotely driven vehicle.

[0101] As shown in Figure 14, the vehicle system 1d includes a time synchronization device 10d, a communication module 11, a locator 12, a map DB 13, a vehicle status sensor 14, a surrounding monitoring sensor 15, a vehicle control ECU 16, and an autonomous driving ECU 17. The vehicle system 1d is the same as the vehicle system 1 of Embodiment 1, except that it includes a time synchronization device 10d instead of a time synchronization device 10.

[0102] <Outline configuration of time synchronization device 10d> Next, the schematic configuration of the time synchronization device 10d will be explained using Figure 15. As shown in Figure 15, the time synchronization device 10d includes a time acquisition unit 110, a time control unit 120, a time synchronization control unit 130, a status identification unit 140, a time correction unit 150d, a time output unit 160, and a control instruction unit 190 as functional blocks. The time synchronization device 10d includes a time correction unit 150d instead of a time correction unit 150. The time synchronization device 10d includes a control instruction unit 190. Except for these points, the time synchronization device 10d is the same as the time synchronization device 10 of Embodiment 1. This time synchronization device 10d also corresponds to a vehicle time correction device.

[0103] The control instruction unit 190 issues an instruction to decelerate the vehicle to a predetermined speed or below, or to stop it, if the difference between the absolute time and the internal time, which has been corrected by the time control unit 120, is greater than or equal to a predetermined value. The absolute time used is the absolute time acquired by the time acquisition unit 110. The predetermined value can be set to any value that can be arbitrarily configured. The predetermined speed can be a vehicle speed that is estimated to be unlikely to cause any discomfort to the occupants even if the internal time is corrected without a correction upper limit. The predetermined speed can be set to any value that can be arbitrarily configured. The control instruction unit 190 should issue an instruction to the automatic driving ECU 17 to decelerate the vehicle to a predetermined speed or below, or to stop it. The instruction from the control instruction unit 190 to decelerate the vehicle to a predetermined speed or stop it will be referred to as a control instruction below.

[0104] The time correction unit 150d is the same as the time correction unit 150 of Embodiment 1, except that some processing differs. These differences will be explained below. The time correction unit 150d corrects the internal time without an upper limit on the correction value after the vehicle has decelerated to a predetermined speed or below or has come to a stop, following a control instruction from the control instruction unit 190. With this configuration, even if the required correction amount is large, it is possible to correct the internal time quickly while making it less likely for the occupants to notice any inconvenience. The time correction unit 150d only needs to postpone correcting the internal time until the vehicle has decelerated to a predetermined speed or below or has come to a stop.

[0105] <Time correction related processing in time synchronization device 10d> Here, using the flowchart in Figure 16, we will explain an example of the time correction-related processing flow in the time synchronization device 10d. The flowchart in Figure 16 should be configured to start when absolute time information is received by the locator 12 after time acquisition has been interrupted. In addition, if the configuration allows switching the automatic driving function on and off, the condition that the automatic driving function is turned on may also be added.

[0106] The processing from steps S41 to S43 should be the same as the processing from S1 to S3. In step S44, the control instruction unit 190 determines whether the required correction amount identified in S43 is greater than or equal to a specified value. In other words, it determines whether the difference between the absolute time obtained in S41 and the internal time generated in S42 is greater than or equal to a specified value. If the required correction amount is less than the specified value (YES in S44), the process moves to step S46. On the other hand, if the required correction amount is greater than or equal to the specified value (NO in S44), the process moves to step S45.

[0107] In step S45, the control instruction unit 190 issues the aforementioned control instruction, and the process moves to step S46. In step S46, the same processing as in S4 is performed. In step S47, the same processing as in S5 is performed. In S47, the fact that the control instruction unit 190 issued a control instruction in S45 should be included in the situation for postponing the correction of the internal time. The processing from steps S48 to S53 is the same as the processing from S6 to S11. Note that the configuration of Embodiment 5 may be combined with the configurations of Embodiments 2 to 4.

[0108] (Embodiment 6) In the above-described embodiment, the configuration in which the time correction units 150, 150a, 150b, 150c, and 150d correct the internal time was shown, but the system is not necessarily limited to this. For example, the time synchronization control unit 130 may also be configured to perform the internal time correction. In addition, the less the occupant is involved in driving a vehicle, the more likely it is that the time synchronization devices 10, 10a, 10b, 10c, and 10d will be used to reduce the likelihood of the occupant noticing malfunctions. Therefore, it is preferable to use the time synchronization devices 10, 10a, 10b, 10c, and 10d in an autonomous vehicle capable of autonomous driving without monitoring obligations. It is even more preferable to use the time synchronization devices 10, 10a, 10b, 10c, and 10d in an autonomous vehicle capable of autonomous driving with sleep permission. Furthermore, it is even more preferable to use the time synchronization devices 10, 10a, 10b, 10c, and 10d in an autonomous vehicle capable of remote autonomous driving.

[0109] This disclosure is not limited to the embodiments described above, and various modifications are possible within the scope of the claims. Embodiments obtained by appropriately combining the technical means disclosed in different embodiments are also included in the technical scope of this disclosure. Furthermore, the control unit and method described in this disclosure may be implemented by a dedicated computer comprising a processor programmed to execute one or more functions embodied by a computer program. Alternatively, the apparatus and method described in this disclosure may be implemented by a dedicated hardware logic circuit. Alternatively, the apparatus and method described in this disclosure may be implemented by one or more dedicated computers comprising a combination of a processor that executes a computer program and one or more hardware logic circuits. Furthermore, the computer program may be stored as instructions executed by the computer on a computer-readable non-transitional tangible recording medium. [Explanation of Symbols]

[0110] 1,1a,1b,1c,1d Vehicle system, 10,10a,10b,10c,10d Time synchronization device (vehicle time correction device), 110 Time acquisition unit, 120 Time control unit, 130 Time synchronization control unit, 140,140a,140b Status identification unit, 150,150a,150b,150c,150d Time correction unit, 170 Provisional acquisition unit, 180 External output unit (information output unit), 190 Limitation instruction unit

Claims

1. A vehicle time correction device used in vehicles that utilize internal time for automatic driving control, A time acquisition unit (110) that sequentially acquires high-precision time information, which is more accurate than the internal time, received by communication from outside the vehicle, A time synchronization control unit (130) sequentially synchronizes the internal time with the high-precision time based on the high-precision time information acquired sequentially by the time acquisition unit, If the acquisition of the high-precision time information by the time acquisition unit is interrupted, the vehicle has a time control unit (120) that autonomously compensates for the internal time, When the acquisition of high-precision time information by the time acquisition unit is resumed after the interruption, a time correction unit (150, 150a, 150b, 150c, 150d) corrects the difference between the high-precision time and the internal time that was being compensated for by the time control unit, The system includes a situation identification unit (140, 140a, 140b) that identifies at least one of the situations in which the vehicle is located and the situation of the vehicle itself, The time correction unit changes the correction upper limit, which is the upper limit of the correction amount per correction by the time correction unit, according to the situation identified by the situation identification unit. The aforementioned situation identification unit identifies whether or not the vehicle is in the process of being driven autonomously by remote control, The time correction unit corrects the internal time by making the correction upper limit smaller than when the situation identification unit identifies that the vehicle is being driven automatically by remote control, based on the situation identification unit identifying that the vehicle is being driven automatically by remote control, and corrects the internal time by making the correction upper limit larger than when the situation identification unit identifies that the vehicle is being driven automatically by remote control, based on the situation identification unit identifying that the vehicle is being driven automatically by remote control.

2. A vehicle time correction device used in vehicles that utilize internal time for automatic driving control, A time acquisition unit (110) that sequentially acquires high-precision time information, which is more accurate than the internal time, received by communication from outside the vehicle, A time synchronization control unit (130) sequentially synchronizes the internal time with the high-precision time based on the high-precision time information acquired sequentially by the time acquisition unit, If the acquisition of the high-precision time information by the time acquisition unit is interrupted, the vehicle has a time control unit (120) that autonomously compensates for the internal time, When the acquisition of high-precision time information by the time acquisition unit is resumed after the interruption, a time correction unit (150, 150a, 150b, 150c, 150d) corrects the difference between the high-precision time and the internal time that was being compensated for by the time control unit, The system includes a situation identification unit (140, 140a, 140b) that identifies at least one of the situations in which the vehicle is located and the situation of the vehicle itself, The time correction unit changes the correction upper limit, which is the upper limit of the correction amount per correction by the time correction unit, according to the situation identified by the situation identification unit. The aforementioned situation identification unit identifies the vehicle speed as the aforementioned situation, The time correction unit corrects the internal time by decreasing the correction upper limit in accordance with the vehicle speed of the vehicle identified by the situation identification unit, and corrects the internal time by increasing the correction upper limit in accordance with the vehicle speed of the vehicle identified by the situation identification unit,

3. A vehicle time correction device according to claim 2, The aforementioned situation identification unit identifies the predicted behavior, which is the predicted behavior of the vehicle in the automatic driving control, as the situation. The time correction unit, when the situation identification unit identifies the predicted behavior in which the vehicle's speed falls below a predetermined value or stops within a set time, suspends the correction of the internal time until the actual behavior of the vehicle reaches that predicted behavior, and then corrects the internal time without the correction upper limit after the predicted behavior is reached.

4. A vehicle time correction device used in vehicles that utilize internal time for automatic driving control, A time acquisition unit (110) that sequentially acquires high-precision time information, which is more accurate than the internal time, received by communication from outside the vehicle, A time synchronization control unit (130) sequentially synchronizes the internal time with the high-precision time based on the high-precision time information acquired sequentially by the time acquisition unit, If the acquisition of the high-precision time information by the time acquisition unit is interrupted, the vehicle has a time control unit (120) that autonomously compensates for the internal time, When the acquisition of high-precision time information by the time acquisition unit is resumed after the interruption, a time correction unit (150, 150a, 150b, 150c, 150d) corrects the difference between the high-precision time and the internal time that was being compensated for by the time control unit, The system includes a situation identification unit (140, 140a, 140b) that identifies at least one of the situations in which the vehicle is located and the situation of the vehicle itself, The time correction unit changes the correction upper limit, which is the upper limit of the correction amount per correction by the time correction unit, according to the situation identified by the situation identification unit. The aforementioned situation identification unit (140, 140a) identifies the shape of the vehicle's travel path as the aforementioned situation, The time correction unit (150, 150a, 150c, 150d) corrects the internal time by making the correction upper limit smaller than when the shape of the road is a straight road when the shape of the road identified by the situation identification unit is a curved road, and corrects the internal time by making the correction upper limit larger than when the shape of the road is a curved road when the shape of the road identified by the situation identification unit is a straight road.

5. A vehicle time correction device used in vehicles that utilize internal time for automatic driving control, A time acquisition unit (110) that sequentially acquires high-precision time information, which is more accurate than the internal time, received by communication from outside the vehicle, A time synchronization control unit (130) sequentially synchronizes the internal time with the high-precision time based on the high-precision time information acquired sequentially by the time acquisition unit, If the acquisition of the high-precision time information by the time acquisition unit is interrupted, the vehicle has a time control unit (120) that autonomously compensates for the internal time, When the acquisition of high-precision time information by the time acquisition unit is resumed after the interruption, a time correction unit (150, 150a, 150b, 150c, 150d) corrects the difference between the high-precision time and the internal time that was being compensated for by the time control unit, The system includes a situation identification unit (140, 140a, 140b) that identifies at least one of the situations in which the vehicle is located and the situation of the vehicle itself, The time correction unit changes the correction upper limit, which is the upper limit of the correction amount per correction by the time correction unit, according to the situation identified by the situation identification unit. The situation identification unit (140b) identifies the planned entry of the vehicle into a target curved road, which is a curved road where the occurrence of at least one of a lateral acceleration and lateral jerk exceeding a threshold is estimated to occur. The time correction unit (150b) is a vehicle time correction device that, when the situation identification unit identifies the vehicle's planned entry into the target curved road, completes the correction of the internal time on the straight road before the vehicle enters the target curved road.

6. A vehicle time correction device used in vehicles that utilize internal time for automatic driving control, A time acquisition unit (110) that sequentially acquires high-precision time information, which is more accurate than the internal time, received by communication from outside the vehicle, A time synchronization control unit (130) sequentially synchronizes the internal time with the high-precision time based on the high-precision time information acquired sequentially by the time acquisition unit, If the acquisition of the high-precision time information by the time acquisition unit is interrupted, the vehicle has a time control unit (120) that autonomously compensates for the internal time, When the acquisition of high-precision time information by the time acquisition unit is resumed after the interruption, a time correction unit (150, 150a, 150b, 150c, 150d) corrects the difference between the high-precision time and the internal time that was being compensated for by the time control unit, The system includes a situation identification unit (140, 140a, 140b) that identifies at least one of the situations in which the vehicle is located and the situation of the vehicle itself, The time correction unit changes the correction upper limit, which is the upper limit of the correction amount per correction by the time correction unit, according to the situation identified by the situation identification unit. The aforementioned situation identification unit (140a) identifies whether or not the vehicle is allowed to pass in the traffic infrastructure that switches whether or not the vehicle is allowed to pass, as the aforementioned situation. The time correction unit (150a) corrects the internal time by reducing the correction upper limit compared to when passage on the traffic infrastructure is not permitted, when the situation identification unit determines that passage on the traffic infrastructure is permitted, while when the situation identification unit determines that passage on the traffic infrastructure is not permitted, it suspends the correction of the internal time until the vehicle stops on the traffic infrastructure, and then corrects the internal time without the correction upper limit after the vehicle has stopped.

7. A vehicle time correction device used in vehicles that utilize internal time for automatic driving control, A time acquisition unit (110) that sequentially acquires high-precision time information, which is more accurate than the internal time, received by communication from outside the vehicle, A time synchronization control unit (130) sequentially synchronizes the internal time with the high-precision time based on the high-precision time information acquired sequentially by the time acquisition unit, If the acquisition of the high-precision time information by the time acquisition unit is interrupted, the vehicle has a time control unit (120) that autonomously compensates for the internal time, When the acquisition of high-precision time information by the time acquisition unit is resumed after the interruption, a time correction unit (150, 150a, 150b, 150c, 150d) corrects the difference between the high-precision time and the internal time that was being compensated for by the time control unit, The system includes a situation identification unit (140, 140a, 140b) that identifies at least one of the situations in which the vehicle is located and the situation of the vehicle itself, The time correction unit changes the correction upper limit, which is the upper limit of the correction amount per correction by the time correction unit, according to the situation identified by the situation identification unit. The aforementioned situation identification unit identifies the distance between the vehicle and at least one of the target vehicles, which is either a preceding vehicle or a following vehicle, as the aforementioned situation. The time correction unit corrects the internal time by decreasing the correction upper limit in accordance with the decrease in the inter-vehicle distance identified by the situation identification unit, and corrects the internal time by increasing the correction upper limit in accordance with the increase in the inter-vehicle distance identified by the situation identification unit.

8. A vehicle time correction device used in vehicles that utilize internal time for automatic driving control, A time acquisition unit (110) that sequentially acquires high-precision time information, which is more accurate than the internal time, received by communication from outside the vehicle, A time synchronization control unit (130) sequentially synchronizes the internal time with the high-precision time based on the high-precision time information acquired sequentially by the time acquisition unit, If the acquisition of the high-precision time information by the time acquisition unit is interrupted, the vehicle has a time control unit (120) that autonomously compensates for the internal time, When the acquisition of high-precision time information by the time acquisition unit is resumed after the interruption, a time correction unit (150, 150a, 150b, 150c, 150d) corrects the difference between the high-precision time and the internal time that was being compensated for by the time control unit, The system includes a situation identification unit (140, 140a, 140b) that identifies at least one of the situations in which the vehicle is located and the situation of the vehicle itself, The time correction unit changes the correction upper limit, which is the upper limit of the correction amount per correction by the time correction unit, according to the situation identified by the situation identification unit. The aforementioned situation identification unit identifies whether the vehicle is in autonomous driving mode via remote control and whether there is a malfunction in the surrounding monitoring sensor used for monitoring the vehicle's surroundings. The time correction unit corrects the internal time of a vehicle when the vehicle is in remote-controlled automatic operation and the situation identification unit identifies a malfunction in the surrounding monitoring sensor, by increasing the correction upper limit compared to when the vehicle is not in remote-controlled automatic operation or when the situation identification unit identifies no malfunction in the surrounding monitoring sensor.

9. A vehicle time correction device according to any one of claims 1 to 8, The system includes a control instruction unit (190) that issues an instruction to decelerate or stop the vehicle at a predetermined speed or below when the difference between the high-precision time and the internal time that has been interpolated by the time control unit is greater than or equal to a specified value. The time correction unit (150d) is a vehicle time correction device that corrects the internal time without an upper limit for correction after the vehicle has decelerated to or stopped below the predetermined speed following an instruction from the control instruction unit.

Images