JP7074660B2 - Self-driving vehicle system - Google Patents

Description

The present invention relates to an autonomous driving vehicle system capable of merging by autonomous driving.

Conventionally, a device for supporting the merging of own vehicles on a highway has been known (see, for example, Patent Document 1). In the device described in Patent Document 1, the inter-vehicle space where the own vehicle can join the main line is detected based on the traffic information including the position and speed of other vehicles traveling on the main line, and when there is a space where the own vehicle can join. Provides the first merge guidance. On the other hand, if there is no space available for merging, a second merging guidance is given after instructing the vehicle to decelerate or stop.

Patent Document 1: Japanese Unexamined Patent Publication No. 2006-244142

By the way, in order to realize the merging without hindering the running of other vehicles on the main line, it is necessary to sufficiently accelerate the own vehicle before reaching the merging point of the main line. However, since the acceleration performance differs from vehicle to vehicle, for example, when own vehicles with low acceleration performance are merged by automatic driving, they can only merge when the inter-vehicle distance is sufficiently long, so there is an opportunity to merge. It may decrease and the stopped time before merging may become longer.

The self-driving vehicle system, which is one aspect of the present invention, generates an action plan for the self-driving vehicle according to the peripheral situation detection unit that detects the peripheral situation of the self-driving vehicle and the peripheral situation detected by the peripheral situation detection unit. It is provided with an action plan generation unit and a travel control unit that controls a travel actuator of an autonomous driving vehicle according to an action plan generated by the action plan generation unit. In the action plan generation unit, while the self-driving vehicle is traveling in the first lane, the self-driving vehicle is between the first vehicle in the second lane and the second vehicle behind it until the stop point on the first lane is reached. When it is determined by the first merging determination unit that determines whether or not merging is possible at the merging point and the first merging determination unit, the automatically driving vehicle is stopped at the stop point and is in the second lane. Generates an action plan for merging of automatically driven vehicles according to the judgment results of the second merging judgment unit, the first merging judgment unit, and the second merging judgment unit, which determine whether or not merging is possible at the merging point of the vehicle. It has a merging command unit and a stop point setting unit for setting a stop point, and the first merging determination unit and the second merging determination unit have a vehicle-to-vehicle distance between the first vehicle and the second vehicle after a predetermined time. When the value is equal to or higher than the specified value, the self-driving vehicle can reach the confluence within a predetermined time, and the vehicle speed of the self-driving vehicle after the predetermined time can increase to the target vehicle speed, the confluence occurs at the confluence. Determining that it is possible, the stop point setting unit sets the first point on the vehicle traveling direction side as the maximum acceleration that can occur from the stopped state of the automatically driven vehicle is larger.

According to the present invention, even an autonomous driving vehicle having a low acceleration performance can realize smooth merging traveling as in the case of an autonomous driving vehicle having a high acceleration performance.

The figure which shows the schematic structure of the traveling system of the autonomous driving vehicle to which the autonomous driving vehicle system which concerns on embodiment of this invention is applied. The block diagram schematically showing the whole structure of the autonomous driving vehicle system which concerns on embodiment of this invention. The figure which shows an example of the action plan at the time of a merging run generated by the action plan generation part of FIG. The block diagram which shows the structure of the controller of FIG. 2 in more detail. The figure for demonstrating the calculation method of the merging point at the time of merging running. The figure which shows an example of the stop point of the vehicle before merging running. The figure which shows an example of the change of the target vehicle speed at the time of merging running. The flowchart which shows an example of the process in the action plan generation part of FIG. The figure which shows concrete example of the main operation of the self-driving vehicle system which concerns on embodiment of this invention.

Hereinafter, embodiments of the present invention will be described with reference to FIGS. 1 to 9. The autonomous driving vehicle system according to the embodiment of the present invention is applied to a vehicle having an automatic driving function (automated driving vehicle). FIG. 1 is a diagram showing a schematic configuration of a traveling system of an autonomous driving vehicle 200 (sometimes simply referred to as a vehicle or an own vehicle) to which the autonomous driving vehicle system according to the present embodiment is applied. The vehicle 200 can travel not only in an automatic driving mode that does not require a driver's driving operation, but also in a manual driving mode by the driver's driving operation. In this embodiment, an operation mode that does not require all operations of accelerator operation, brake operation, and steering is referred to as an automatic operation mode.

As shown in FIG. 1, the vehicle 200 has an engine 1 and a transmission 2. The engine 1 mixes the intake air supplied through the throttle valve 11 and the fuel injected from the injector 12 at an appropriate ratio, ignites the engine with a spark plug or the like, and burns the engine, thereby generating rotational power. An engine (eg a gasoline engine). In addition, various engines such as a diesel engine can be used instead of the gasoline engine. The amount of intake air is adjusted by the throttle valve 11, and the opening degree of the throttle valve 11 is changed by driving a throttle actuator operated by an electric signal. The opening degree of the throttle valve 11 and the fuel injection amount (injection timing, injection time) from the injector 12 are controlled by the controller 40 (FIG. 2).

The transmission 2 is provided in the power transmission path between the engine 1 and the drive wheels 3, shifts the rotation from the engine 1, converts the torque from the engine 1, and outputs the torque. The rotation shifted by the transmission 2 is transmitted to the drive wheels 3, whereby the vehicle 200 travels. In addition, instead of the engine 1, or in addition to the engine 1, a traveling motor as a drive source may be provided to form the vehicle 200 as an electric vehicle or a hybrid vehicle.

The transmission 2 is, for example, a stepped transmission in which the gear ratio can be changed stepwise according to a plurality of gears. A continuously variable transmission whose gear ratio can be changed steplessly can also be used as the transmission 2. Although not shown, the power from the engine 1 may be input to the transmission 2 via the torque converter. The transmission 2 includes an engaging element 21 such as a dog clutch or a friction clutch, and the hydraulic control device 22 controls the flow of oil from the hydraulic source to the engaging element 21 to change the transmission stage of the transmission 2. can do. The hydraulic control device 22 has a control valve driven by an electric signal, and an appropriate shift stage can be set by changing the flow of pressure oil to the engaging element 21 according to the drive of the control valve.

FIG. 2 is a block diagram schematically showing the overall configuration of the autonomous driving vehicle system 100 according to the embodiment of the present invention. As shown in FIG. 2, the autonomous driving vehicle system 100 includes a controller 40, an external sensor group 31 electrically connected to the controller 40, an internal sensor group 32, an input / output device 33, and a GPS receiver 34. It mainly has a map database 35, a navigation device 36, a communication unit 37, and a traveling actuator AC.

The external sensor group 31 is a general term for a plurality of sensors that detect an external situation, which is peripheral information of the vehicle 200. For example, the external sensor group 31 includes a lidar that measures scattered light with respect to omnidirectional irradiation light of the vehicle 200 to measure the distance from the vehicle 200 to surrounding obstacles, and a vehicle that detects reflected waves by irradiating electromagnetic waves. Radars that detect other vehicles and obstacles around the 200, cameras mounted on the vehicle 200 that have image sensors such as CCD and CMOS to capture the surroundings (front, rear, and sides) of the vehicle 200, etc. included. The detection signal by the external sensor group 31 is transmitted to the controller 40.

The internal sensor group 32 is a general term for a plurality of sensors that detect the traveling state of the vehicle 200 and the state inside the vehicle. For example, the internal sensor group 32 includes a vehicle speed sensor that detects the vehicle speed of the vehicle 200, an acceleration sensor that detects the acceleration in the front-rear direction and the acceleration in the left-right direction (lateral acceleration) of the vehicle 200, and an engine that detects the rotation speed of the engine 1. It includes a rotation speed sensor, a yaw rate sensor that detects the rotation angle speed around the vertical axis of the center of gravity of the vehicle 200, a throttle opening degree sensor that detects the opening degree (throttle opening degree) of the throttle valve 11. The internal sensor group 32 also includes sensors that detect driver operation operations in the manual operation mode, such as accelerator pedal operation, brake pedal operation, and steering operation. The detection signal by the internal sensor group 32 is transmitted to the controller 40.

The input / output device 33 is a general term for devices for which commands are input from the driver and information is output to the driver. For example, the input / output device 33 includes various switches for the driver to input various commands by operating an operation member, a microphone for the driver to input commands by voice, a display unit for providing information to the driver via a display image, and voice to the driver. Includes speakers and the like that provide information in. Various switches include a manual automatic changeover switch that commands either an automatic operation mode or a manual operation mode.

The manual automatic changeover switch is configured as a switch that can be manually operated by the driver, for example, and gives a command to switch to an automatic operation mode in which the automatic operation function is enabled or a manual operation mode in which the automatic operation function is disabled, depending on the switch operation. Output. It is also possible to instruct switching from the manual operation mode to the automatic operation mode or switching from the automatic operation mode to the manual operation mode when a predetermined driving condition is satisfied, regardless of the operation of the manual automatic changeover switch. That is, by automatically switching the manual automatic changeover switch, the mode changeover can be performed automatically instead of manually.

The GPS receiver 34 receives positioning signals from a plurality of GPS satellites, and measures the absolute position (latitude, longitude, etc.) of the vehicle 200 based on the received signals. The signal from the GPS receiver 34 is transmitted to the controller 40.

The map database 35 is a device for storing general map information used in the navigation device 36, and is composed of, for example, a hard disk. Map information includes road position information, road shape (curvature, etc.) information, and intersection and branch point position information. The map information stored in the map database 35 is different from the highly accurate map information stored in the storage unit 42 of the controller 40.

The navigation device 36 is a device that searches for a target route on the road to the destination input by the driver and provides guidance along the target route. The input of the destination and the guidance along the target route are performed via the input / output device 33. The target route is calculated based on the current position of the vehicle 200 measured by the GPS receiver 34 and the map information stored in the map database 35.

The communication unit 37 communicates with various servers (not shown) via a network including a wireless communication network such as an Internet line, and acquires map information, traffic information, and the like from the server periodically or at an arbitrary timing. The acquired map information is output to the map database 35 and the storage unit 42, and the map information is updated. The acquired traffic information includes traffic congestion information and signal information such as the remaining time until the signal changes from red to blue.

The actuator AC is a device for operating various devices related to the traveling operation of the vehicle 200. The actuator AC includes a throttle actuator that adjusts the opening degree (throttle opening degree) of the throttle valve 11 of the engine 1 shown in FIG. 1, and a shift stage of the transmission 2 that controls the flow of oil to the engaging element 21. It includes a speed change actuator to be changed, a brake actuator for operating a braking device, a steering actuator for driving a steering device, and the like.

The controller 40 is composed of an electronic control unit (ECU). A plurality of ECUs having different functions, such as an engine control ECU and a transmission control ECU, can be separately provided, but in FIG. 2, the controller 40 is shown as a set of these ECUs for convenience. The controller 40 includes a computer having a calculation unit 41 such as a CPU, a storage unit 42 such as a ROM, RAM, and a hard disk, and other peripheral circuits (not shown).

The storage unit 42 stores high-precision detailed map information including information on the center position of the lane and information on the boundary of the lane position. More specifically, as map information, road information, traffic regulation information, address information, facility information, telephone number information and the like are stored. Road information includes information indicating the type of road such as highways, toll roads, and national roads, the number of lanes of the road, the width of each lane, the slope of the road, the three-dimensional coordinate position of the road, the curvature of the curve of the lane, and the lane. Information such as the positions of confluence points and branch points, road signs, etc. is included. Traffic regulation information includes information that lane driving is restricted or closed due to construction work or the like. The storage unit 42 also stores information such as a shift map (shift diagram) that serves as a reference for shifting operations, various control programs, and threshold values used in the programs.

The calculation unit 41 has a vehicle position recognition unit 43, an outside world recognition unit 44, an action plan generation unit 45, and a travel control unit 46 as functional configurations related to automatic driving.

The own vehicle position recognition unit 43 recognizes the position of the vehicle 200 (own vehicle position) on the map based on the position information of the vehicle 200 received by the GPS receiver 34 and the map information of the map database 35. The own vehicle position may be recognized by using the map information (information such as the shape of the building) stored in the storage unit 42 and the peripheral information of the vehicle 200 detected by the external sensor group 31, thereby the own vehicle position. Can be recognized with high accuracy. When the position of the own vehicle can be measured by a sensor installed on the road or outside the side of the road, the position of the own vehicle can be recognized with high accuracy by communicating with the sensor via the communication unit 37. can.

The outside world recognition unit 44 recognizes the external situation around the vehicle 200 based on the signals from the external sensor group 31 such as the rider, the radar, and the camera. For example, the position, speed, and acceleration of peripheral vehicles (front and rear vehicles) traveling around the vehicle 200, the position of peripheral vehicles stopped or parked around the vehicle 200, and the position and state of other objects. recognize. Other objects include signs, traffic lights, road boundaries and stop lines, buildings, guardrails, utility poles, signs, pedestrians, bicycles and the like. The state of other objects includes the color of the traffic light (red, blue, yellow), the speed and orientation of pedestrians and bicycles, and so on.

The action plan generation unit 45 is currently based on, for example, the target route calculated by the navigation device 36, the vehicle position recognized by the vehicle position recognition unit 43, and the external situation recognized by the outside world recognition unit 44. The traveling track (target track) of the vehicle 200 from to a predetermined time ahead is generated. When there are multiple orbits that are candidates for the target orbit on the target route, the action plan generation unit 45 selects the optimum orbit from among them that meets the criteria such as observing laws and regulations and driving efficiently and safely. Then, the selected orbit is set as the target orbit. Then, the action plan generation unit 45 generates an action plan according to the generated target trajectory.

In the action plan, the travel plan data set every unit time Δt (for example, 0.1 second) from the present time to a predetermined time T (for example, 5 seconds) ahead, that is, the time for each unit time Δt is associated with the action plan. The travel plan data to be set is included. The travel plan data includes the position data of the vehicle 200 and the vehicle state data for each unit time. The position data is, for example, data of a target point indicating a two-dimensional coordinate position on a road, and the vehicle state data is vehicle speed data indicating a vehicle speed, direction data indicating the direction of the vehicle 200, and the like. The travel plan is updated every unit time.

The action plan generation unit 45 generates a target trajectory by connecting position data for each unit time Δt from the current time to a predetermined time T ahead in chronological order. At this time, the acceleration (target acceleration) for each unit time Δt is calculated based on the vehicle speed (target vehicle speed) at each target point for each unit time Δt on the target track. That is, the action plan generation unit 45 calculates the target vehicle speed and the target acceleration. The target acceleration may be calculated by the traveling control unit 46.

When the action plan generation unit 45 generates the target track, the action plan generation unit 45 first determines the traveling mode. Specifically, follow-up driving to follow the vehicle in front, overtaking driving to overtake the vehicle in front, lane-changing driving to change the driving lane, merging driving to join the main lane of a highway or toll road, and not to deviate from the driving lane. Determine the driving mode such as lane keeping driving, constant speed driving, decelerating driving, or accelerating driving that keeps the lane. Then, a target track is generated based on the traveling mode.

FIG. 3 is a diagram showing an example of an action plan generated by the action plan generation unit 45 at the time of merging running. That is, FIG. 3 shows a traveling plan in which the lane is changed from the acceleration lane 301 and merges with the main lane 302, and more specifically, the traveling plan merges between the first vehicle 201 and the second vehicle 202 traveling on the main lane 302. .. The solid line indicating the first vehicle 201 and the second vehicle 202 indicates the current position of the first vehicle 201 and the second vehicle 202, and the dotted line indicates the position expected at the time of merging. Each point P in FIG. 3 corresponds to position data for each unit time from the present time to a predetermined time ahead, and by connecting these points P in chronological order, a target trajectory 303 can be obtained. The position of the vehicle 200 at the present time is the point Pa. The travel plan for merging travel is generated by predicting the positions of the first vehicle 201 and the second vehicle 202 when the vehicle 200 reaches the merging point Pb on the main line 302. That is, the confluence point Pb is set so as not to interfere with the traveling of the first vehicle 201 and the second vehicle 202.

The travel control unit 46 controls each actuator AC so that the vehicle 200 travels along the target track generated by the action plan generation unit 45 in the automatic driving mode. That is, the throttle actuator, the speed change actuator, the brake actuator, the steering actuator, and the like are controlled so that the vehicle 200 passes the target point P for each unit time.

More specifically, the travel control unit 46 takes into consideration the travel resistance determined by the road gradient or the like in the automatic driving mode, and the required driving force for obtaining the target acceleration for each unit time calculated by the action plan generation unit 45. Is calculated. Then, for example, the actuator AC is feedback-controlled so that the actual acceleration detected by the internal sensor group 32 becomes the target acceleration. That is, the actuator AC is controlled so that the vehicle 200 travels at the target vehicle speed and the target acceleration. In the manual operation mode, the travel control unit 46 controls each actuator AC in response to a travel command (accelerator opening degree, etc.) from the driver acquired by the internal sensor group 32.

By the way, as shown in FIG. 3, when the vehicle 200 merges from the acceleration lane 301 to the main lane 302, an action plan is made so as not to interfere with the traveling of other vehicles (first vehicle 201, second vehicle 202) traveling on the main lane 302. Is generated, and the vehicle 200 runs based on the action plan. Therefore, when it is difficult to merge because the distance between the first vehicle 201 and the second vehicle 202 is short, the vehicle 200 can be stopped at, for example, the stop point Pc in FIG. 3 to merge. Wait until That is, the action plan generation unit 45 generates an action plan that stops the vehicle 200 at the stop point Pc.

When the vehicle 200 is merged with the main line 302 from the state where the vehicle 200 is stopped in this way, it is necessary to accelerate the vehicle 200, but the acceleration performance (maximum acceleration) differs for each vehicle 200. Therefore, when the vehicles 200 having low acceleration performance are merged by automatic driving, it is necessary to make the distance between the first vehicle 201 and the second vehicle 202 (the distance between the vehicles permitted to merge) sufficiently long. As a result, the chances of the vehicle 200 merging are reduced, the stop time of the vehicle 200 becomes longer, and there is a risk of causing traffic congestion. In order to solve such a problem, in the present embodiment, the autonomous driving vehicle system 100 is configured as follows.

FIG. 4 is a block diagram showing in more detail the configuration of the controller 40 of FIG. 2, mainly the configuration of the action plan generation unit 45. As shown in FIG. 4, the action plan generation unit 45 has a merging point calculation unit 451, a maximum acceleration calculation unit 452, a stop point determination unit 453, a merging determination unit 454, and a merging command unit 455 as functional configurations. And have.

When the merging point calculation unit 451 generates an action plan for merging travel, the merging point calculation unit 451 is on the main line 302 based on the own vehicle position recognized by the own vehicle position recognition unit 43 and the external situation recognized by the outside world recognition unit 44. Calculate the confluence point Pb of the target. FIG. 5 is a diagram for explaining a method of calculating the confluence point Pb. As shown in FIG. 5, the current position of the vehicle 200 on the acceleration lane 301 (local point Pa) is set as the origin, the X axis is taken along the acceleration lane 301, and Y is perpendicular to the acceleration lane 301 toward the main lane 302. Define the XY coordinates on the axis. At this time, the coordinates of the current point P1 of the first vehicle 201 recognized by the outside world recognition unit 44 based on the signals from the external sensor group 31 such as the laser, rider, and camera are (x1, y1), and the second vehicle 202. The coordinates of the point P2 of are (x2, y2). The local point Pa (origin of XY coordinates) changes with the passage of time.

In calculating the merging point Pb, the merging point calculation unit 451 first calculates the vehicle speed V1 of the first vehicle 201 and the vehicle speed V2 of the second vehicle 202 at the present time. The vehicle speeds V1 and V2 detect the vehicle speed V0 of the own vehicle 200 based on the signal from the internal sensor group 32, and the own vehicle 200, the first vehicle 201, and the second vehicle 202 based on the signal from the external sensor group 31. The amount of change in the distance between the vehicle and the vehicle can be detected and calculated based on the vehicle speed V0 and the amount of change in the distance. The vehicle speed information of the first vehicle 201 and the second vehicle 202 may be acquired via the communication unit 37.

Next, the merging point calculation unit 451 uses the vehicle speeds V1 and V2 when the first vehicle 201 and the second vehicle 202 are traveling at the current vehicle speeds V1 and V2, for example, after a predetermined time ΔT from the current time. The coordinates (x1', y1') and (x2', y2') at the points P1'and P2' on the main line 302 of the first vehicle 201 and the second vehicle 202 are calculated, respectively. When the first vehicle 201 and the second vehicle 202 are currently accelerating or decelerating, the vehicle speeds V1 and V2 are changed to position coordinates (x1', y1'), (x2') after a predetermined time ΔT. , Y2'). The predetermined time ΔT is set for each unit time Δt (for example, 0.1 second) which is the setting interval of the travel plan data, and the merging point calculation unit 451 of the first vehicle 201 and the second vehicle 202 for each unit time Δt. Calculate future position coordinates. That is, the position coordinates corresponding to each predetermined time ΔT of the first vehicle 201 and the second vehicle 202 are calculated with the predetermined time ΔT each time the unit time Δt elapses from the present time as a parameter.

Next, the merging point calculation unit 451 uses the coordinates ((x1'+ x2') / 2, (y1'+ y2) of the midpoint between the point P1'of the first vehicle 201 and the point P2' of the second vehicle 202 after the predetermined time ΔT. ') / 2) is calculated as the confluence point Pb (xb, yb). The confluence point Pb is calculated for each unit time Δt with the predetermined time ΔT as a parameter. The point Pd in FIG. 5 is the end point of the acceleration section (see FIG. 3), and the confluence point Pb is calculated as a position at least in front of the end point Pd in the traveling direction. That is, the confluence point calculation unit 451 calculates the confluence point Pb on condition that the X coordinate value xb of the confluence point Pb is smaller than the X coordinate value xd of the end point Pd.

The maximum acceleration calculation unit 452 calculates the maximum acceleration Amax that the vehicle 200 can generate at the present time. The maximum acceleration Amax is, for example, the maximum engine torque Te under the engine rotation speed predicted at the time of acceleration, the gear ratio α of the transmission 2, the tire radius of the drive wheel 3 (tire radius r), the gradient resistance, and the rolling resistance. , Various resistances β such as air resistance, and vehicle weight W are calculated by the following equation (I). While the vehicle is stopped, the maximum acceleration Amax is obtained when the transmission 2 is changed to the first speed.
Amax = ((Te × α / r) -β) / W ・ ・ ・ (I)

When the vehicle 200 is a hybrid vehicle or an electric vehicle, the maximum acceleration Amax is calculated using the maximum torque of the traveling motor. In this case, the maximum torque of the traveling motor is calculated in consideration of the remaining capacity SOC of the battery. For example, when the remaining capacity SOC of the battery is low and the maximum torque of the traveling motor is limited, the maximum acceleration Amax decreases.

The stop point determination unit 453 determines (sets) the stop point Pc on the acceleration lane 301 according to the acceleration performance (maximum acceleration Amax) when the vehicle 200 is stopped. FIG. 6 is a diagram showing an example of a stop point Pc (Pc1, Pc2) of the vehicle 200 (200A, 200B). The stop point determination unit 453 sets the stop point Pc in consideration of the acceleration performance of the vehicle 200 and the distance to the end point Pd. Specifically, the smaller the maximum acceleration Amax is, the more the stop point Pc is set on the front side (rear side) in the traveling direction. In FIG. 6, the vehicle 200B has lower acceleration performance and a smaller maximum acceleration Amax than the vehicle 200A. Therefore, the stop point Pc2 of the vehicle 200B is set behind the stop point Pc1 of the vehicle 200A by a distance ΔX. As a result, the lower the acceleration performance of the vehicle, the longer the acceleration distance from the stopped state can be taken. The distance ΔX becomes longer as the difference in acceleration performance between the vehicles 200A and 200B is larger.

The stop point determination unit 453 can set deceleration start points Pe1 and Pe2 for commanding the start of deceleration of the vehicle 200 in front of the stop points Pc1 and Ps2. In this case, the deceleration start point Pe2 of the vehicle 200B can be set behind the deceleration start point Pe1 of the vehicle 200A. The deceleration start points Pe1 and Pe2 are set so that, for example, the magnitude (absolute value) of deceleration until the vehicle 200 stops is equal to or less than a predetermined value, that is, the deceleration shock does not become excessive.

The merging determination unit 454 determines the success or failure of the merging condition according to the signals from the merging point calculation unit 451, the maximum acceleration calculation unit 452, and the stop point determination unit 453. The merging condition is that the inter-vehicle distance ΔL (FIG. 5) between the first vehicle 201 and the second vehicle 202 expected after a predetermined time ΔT is equal to or greater than the threshold value ΔLa, and the merging point Pb calculated by the merging point calculation unit 451 It is established when the vehicle 200 can reach within the predetermined time ΔT and the vehicle speed when reaching the confluence point Pb becomes equal to or higher than the final target vehicle speed (final target vehicle speed) Va. This determination is a determination as to whether or not the vehicle 200 can be merged without hindering the traveling of the first vehicle 201 and the second vehicle 202, and the final target vehicle speed Va is set to, for example, the vehicle speed V1 of the first vehicle 201. Will be done. The threshold value ΔLa is set according to the vehicle speed so that it increases as the vehicle speed increases.

The merging determination unit 454 has a first merging determination unit 454A for determining the success or failure of the merging condition while the vehicle 200 is running, and a second merging determination unit 454B for determining the success or failure of the merging condition after the vehicle 200 is stopped. That is, in the present embodiment, first, while the vehicle 200 is traveling, the first merging determination unit 454A determines the success or failure of the merging condition. Then, when the first merging determination unit 454A determines that the merging condition is satisfied, the merging permission is ordered, and when it is determined that the merging condition is not satisfied, the vehicle 200 is determined by the stop point determination unit 453 without instructing the merging permission. The vehicle is stopped at the stop point Pc on the accelerated lane 301.

The processing of the first merging determination unit 454A will be described more specifically. First, the first merging determination unit 454A and the first vehicle 201 are based on the position coordinates (x1', y1') and (x2', y2') of the first vehicle 201 and the second vehicle 202 after a predetermined time ΔT. The inter-vehicle distance ΔL with the second vehicle 202 is calculated, and it is determined whether or not the inter-vehicle distance ΔL is equal to or greater than the threshold value ΔLa. Further, when the vehicle 200 is accelerated by the maximum acceleration Amax calculated by the maximum acceleration calculation unit 452, the time required for the vehicle speed to reach the final target vehicle speed Va is calculated and ΔTmin (referred to as the minimum acceleration time) is calculated. Is set to the initial value ΔT0 of the predetermined time ΔT for determining the success or failure of the merging condition. That is, when the predetermined time ΔT is shorter than the minimum acceleration time ΔTmin, the vehicle speed after the predetermined time ΔT is less than the final target vehicle speed Va, and the merging condition is clearly unsatisfied. Set to.

Then, when the predetermined time ΔT is the initial value ΔT0, the target movement distance D0 from the current point Pa to the confluence point Pb calculated by the confluence point calculation unit 451 corresponding to the predetermined time ΔT0 is calculated and the maximum. The maximum mileage D0max of the vehicle 200 when traveling ΔT0 for a predetermined time at the acceleration Amax is calculated. Next, the first merging determination unit 454A determines whether or not the maximum mileage D0max is equal to or greater than the target travel distance D0 (D0max ≧ D0), and when D0max ≧ D0, the vehicle 200 is within the predetermined time ΔT0. Is movable to the confluence point Pb, so it is determined that the confluence condition is satisfied. On the other hand, when D0max <D0, it is determined that the merging condition is not satisfied, the unit time Δt is added to the predetermined time ΔT, and the predetermined time ΔT is updated from ΔT0 to ΔT1.

Next, the first merging determination unit 454A similarly determines the success or failure of the merging condition using the predetermined time ΔT1 after the update. That is, the target moving distance D1 corresponding to the predetermined time ΔT1 is calculated, and the maximum mileage D1max of the vehicle 200 when traveling ΔT1 for the predetermined time with the maximum acceleration Amax is calculated. When D1max ≧ D1, it is determined that the merging condition is satisfied, and when D1max <D1, it is determined that the merging condition is not satisfied, the unit time Δt is added to the predetermined time ΔT, and the predetermined time ΔT is ΔT1. To update to ΔT2.

After that, until it is determined that the merging condition is satisfied, the first merging determination unit 454A repeats the same process while sequentially updating ΔT for a predetermined time with ΔT3, ΔT4, ΔT5, and so on. In this case, every time the unit time Δt actually elapses, the success or failure of the merging condition is determined while updating the position of the vehicle 200. When the vehicle 200 reaches the stop point Pc determined by the stop point determination unit 453 without satisfying the merging condition, the success / failure determination of the merging condition by the first merging determination unit 454A ends.

The second merging determination unit 454B starts the success / failure determination of the merging condition when the first merging determination unit 454A determines that the merging condition is not satisfied and the vehicle 200 stops at the stop point Pc determined by the stop point determination unit 453. do. Then, when it is determined that the merging condition is satisfied, the merging permission is specified, and when it is determined that the merging condition is not satisfied, the vehicle 200 is stopped and waits at the stop point Pc until it is determined that the merging condition is satisfied. ..

The second merging determination unit 454B determines the success or failure of the merging condition in the same manner as the first merging determination unit 454A. That is, the magnitude of the target travel distance D (D0, D1, D2 ...) after a predetermined time ΔT (T0, T1, T2 ...) From the present time and the maximum mileage Dmax (D0max, D1max, D2max ...) By comparison, the success / failure determination of the merging condition is repeated by updating ΔT for a predetermined time until Dmax ≧ D.

The merging command unit 455 generates an action plan such that the vehicle 200 stops at the stop point Pc before the merging condition is determined by the first merging determination unit 454A . Then, if the first merging determination unit 454A determines that the merging condition is satisfied before the vehicle 200 reaches the stop point Pc, the action plan is revised, the lane is changed to the main lane 302, and the merging running action plan is merged. To generate. Further, after the vehicle 200 has stopped at the stop point Pc, an action plan for maintaining the stopped state is generated, and when the second merging determination unit 454B determines that the merging condition is satisfied in that state, the action plan is created. Modify and generate an action plan for merging.

Specifically, when the merging command unit 455 is determined by the first merging determination unit 454A or the second merging determination unit 454B that the merging condition is satisfied, the merging command unit 455 uses the predetermined time ΔTn when the merging condition is satisfied to perform the merging traveling. Generate an action plan. FIG. 7 is a diagram showing a specific example of the characteristic f1 of the change with time of the target vehicle speed V included in the action plan. FIG. 7 is an example in which the second merging determination unit 454B determines that the merging condition is satisfied, and the vehicle speed V0 at the present time t = 0 is 0. The characteristic f2 is a characteristic of the maximum acceleration Amax, and the slope (acceleration) of the characteristic f1 is equal to or less than the slope of the characteristic f2.

The target vehicle speed V gradually increases to the final target vehicle speed Va before the lapse of the predetermined time ΔTn along the characteristic f1, and is maintained at the final target vehicle speed Va thereafter. The area on the lower side of the characteristic f1 corresponds to the target movement distance Dn corresponding to the predetermined time ΔTn. The target travel distance Dn is equal to or less than the area below the characteristic f2 (maximum mileage Dnmax). As shown in FIG. 7, the merging command unit 455 sets the characteristic f1 such that the vehicle speed after a predetermined time ΔTn is the final target vehicle speed Va and the mileage is the target moving distance Dn. Then, an action plan corresponding to the characteristic f1 is generated, and the action plan is output to the traveling control unit 46.

FIG. 8 is a flowchart showing an example of processing in the action plan generation unit 45 of FIG. In the process shown in this flowchart, for example, in the automatic driving mode, the vehicle 200 travels in the acceleration lane 301, and the first vehicle 201 and the second vehicle 202, which are the reference for calculating the confluence point Pb, are detected and , It starts when the preconditions for merging driving are satisfied.

The preconditions are, for example, (1) that the current positional deviation between the Y coordinates y1 and y2 of the first vehicle 201 and the second vehicle 202 traveling on the main line 302 is small, that is, the absolute value of the difference between y1 and y2 is predetermined. The magnitude (absolute value) of the amount of change in acceleration / deceleration of the first vehicle 201 and the second vehicle 202 is less than the predetermined thresholds. That, (4) the magnitude (absolute value) of the amount of change in yaw rate of the first vehicle 201 and the second vehicle 202 is less than a predetermined threshold, and (5) the X coordinate x1 of the first vehicle 201 becomes the vehicle 200. On the other hand, it is within a certain range, that is, x1 is larger than a predetermined lower limit value and smaller than a predetermined upper limit value, and (6) the X coordinate x2 of the second vehicle 202 is within a certain range with respect to the vehicle 200, that is. For example, x2 is larger than a predetermined lower limit value and smaller than a predetermined upper limit value. When all these preconditions are satisfied, the process of FIG. 8 is started.

First, in step S1, the confluence point Pb of the vehicle 200 after a predetermined time ΔT from the present time is calculated. That is, the coordinates (x1', y1') and (x2', y2') at the points P1'and P2' on the main line 302 of the first vehicle 201 and the second vehicle 202 are calculated, respectively, and the points P1'and P2' Calculate the midpoint. When the vehicle 200 is running and the position of the vehicle 200 changes every unit time Δt, the confluence point Pb after the predetermined time ΔT is calculated with reference to the point of the vehicle 200 after the movement. The initial predetermined time ΔT0 is set to the minimum acceleration time ΔTmin required for the vehicle 200 to reach the final target vehicle speed Va (for example, the vehicle speed V1 of the first vehicle 201).

Next, in step S2, the maximum acceleration Amax that the vehicle 200 can generate at the present time is calculated by the above equation (I) using the maximum engine torque Te, the gear ratio α of the transmission 2, the tire radius r, and various resistances β. .. Next, in step S3, the stop point Pc of the vehicle 200 on the acceleration lane 301 is set according to the maximum acceleration Amax. That is, the smaller the maximum acceleration Amax, the more the stop point Pc is set on the front side (rear side) in the traveling direction (see FIG. 6).

Next, in step S4, it is determined whether or not the merging condition is satisfied. That is, the distance ΔL between the first vehicle 201 and the second vehicle 202 is equal to or greater than the threshold value ΔLa, the vehicle 200 can reach the confluence point Pb calculated in step S1 within a predetermined time ΔT, and the confluence point Pb is reached. It is determined whether or not the vehicle speed at the time of arrival is equal to or higher than the final target vehicle speed Va. If affirmed in step S4, the process proceeds to step S5, and if denied, the process proceeds to step S6.

In step S5, an action plan is generated so that the vehicle 200 reaches the confluence point Pb after a predetermined time ΔT and the vehicle speed at that time becomes the final target vehicle speed Va. For example, an action plan including a change in the target vehicle speed V as shown in FIG. 7 is generated. Then, the action plan is output to the traveling control unit 46. As a result, the vehicle 200 starts merging and traveling according to the action plan.

On the other hand, in step S6, it is determined whether or not the position of the vehicle 200 recognized by the own vehicle position recognition unit 43 has reached the stop point Pc set in step S3. If it is denied in step S6, the process proceeds to step S7, the predetermined time ΔT is updated by the unit time Δt, and the process returns to step S1. On the other hand, if affirmed in step S6, the process proceeds to step S8, an action plan for stopping the vehicle 200 at the stop point Pc is generated, and the action plan is output to the travel control unit 46.

Next, in step S9, the success or failure of the merging condition is determined as in step S4. That is, the distance ΔL between the first vehicle 201 and the second vehicle 202 is equal to or greater than the threshold value ΔLa, the vehicle 200 can reach the confluence point Pb calculated in step S1 within a predetermined time ΔT, and the confluence point Pb is reached. It is determined whether or not the vehicle speed at the time of arrival is equal to or higher than the final target vehicle speed Va. If affirmed in step S9, the process proceeds to step S5, and if denied, the process returns to step S1.

FIG. 9 is a diagram specifically illustrating an example of the main operation of the autonomous driving vehicle system 100. FIG. 9 shows a state (step S8) in which the vehicle 200 is stopped at the stop point Pc without satisfying the merging condition until the vehicle 200 reaches the stop point Pc. For example, since the main line 302 is congested and the inter-vehicle distance ΔL is less than the threshold value ΔLa, the vehicle 200 cannot join and temporarily stops.

Here, it is assumed that the vehicle 200A has a larger maximum acceleration Amax than the vehicle 200B. At this time, the stop point Pc2 of the vehicle 200B is set on the front side (rear side) of the stop point Pc1 of the vehicle 200A in the traveling direction (step S3). As a result, the distance from the stop point Pc2 of the vehicle 200B to the confluence point Pb becomes longer than the distance from the stop point Pc1 of the vehicle 200A to the confluence point Pb. As a result, for example, when a state in which the inter-vehicle distance ΔL is equal to or greater than the threshold value ΔLa is detected, the vehicle 200B can easily reach the final target vehicle speed Va after a predetermined time ΔT, and the first vehicle 201 and the second vehicle 202 travel. Smooth merging is possible without hindering.

Further, since the stop point Pc1 of the vehicle 200A is located ahead of the stop point Pc2 of the vehicle 200B, the vehicle 200A has an increased chance of merging until the vehicle stops. As a result, the probability that the vehicle 200A can merge before stopping increases, and it is possible to realize good merge running by automatic driving.

According to this embodiment, the following effects can be obtained.
(1) The autonomous driving vehicle system 100 according to the present embodiment generates an action plan for the vehicle 200 according to the external sensor group 31 that detects the peripheral condition of the vehicle 200 and the peripheral condition detected by the external sensor group 31. An action plan generation unit 45 is provided, and a travel control unit 46 that controls a travel actuator AC of the vehicle 200 according to the action plan generated by the action plan generation unit 45 (FIG. 2). The action plan generation unit 45 stops the vehicle 200 at the stop point Pc of the acceleration lane 301, and then merges the vehicle 200 between the first vehicle 201 and the second vehicle 202 behind it at the confluence point Pb of the main lane 302. The larger the maximum acceleration Amax that can occur from the stopped state of the vehicle 200, the more the stop point Pc is set on the vehicle traveling direction side (FIG. 6).

As a result, the vehicle 200B having a small maximum acceleration Amax stops on the front side in the traveling direction, so that the acceleration mileage can be lengthened. Therefore, the vehicle 200B can smoothly merge and run. That is, in the case of the vehicle 200B having a small maximum acceleration Amax, there is a high possibility that the vehicle speed will not be sufficient at the merging point Pb. Therefore, unless the inter-vehicle distance ΔL is sufficiently large, merging becomes difficult and the chance of merging decreases. There is a risk of In this respect, in the present embodiment, the vehicle 200B having a lower maximum acceleration Amax starts accelerating from the front side in the traveling direction, so that it can be easily accelerated to the final target vehicle speed Va at the confluence point Pb and is smooth. Confluence running is possible.

(2) The action plan generation unit 45 sets the final target vehicle speed Va based on the vehicle speed V1 of the first vehicle 201, and generates an action plan so that the vehicle speed of the vehicle 200 rises to the final target vehicle speed Va at the confluence point Pb. do. As a result, it is possible to appropriately realize merging running without hindering the running of other vehicles running on the main line 302.

(3) The action plan generation unit 45 calculates the midpoint between the first vehicle 201 and the second vehicle 202 after the predetermined time ΔT as the confluence point Pb, and the vehicle 200 has the maximum acceleration Amax for the predetermined time ΔT. When the maximum mileage Dmax by traveling is equal to or greater than the target travel distance D from the local point Pa to the confluence point Pb, and the vehicle speed of the vehicle 200 after a predetermined time ΔT can increase to the final target vehicle speed Va. Judge that merging is possible. This enables good merging in consideration of the acceleration performance of each vehicle 200.

The above embodiment can be changed to various forms. Hereinafter, a modified example will be described. In the above embodiment, the peripheral condition of the vehicle 200 is detected by the external sensor group 31, but the peripheral condition may be detected via the communication unit 37, and the peripheral condition detection unit is limited to the above-mentioned one. do not have. In the above embodiment, the automatic driving vehicle system 100 is applied when merging from the acceleration lane (first lane) such as a highway or a toll road to the main lane (second lane), but the lane is due to road construction or the like. The automatic driving vehicle system can be similarly applied when changing lanes when the number of lanes decreases, and the first lane and the second lane are not limited to those described above. Therefore, the first point where the vehicle is stopped in the first lane and the second point where the vehicle is merged into the second lane may be other than the above-mentioned stop point Pc and merge point Pb.

In the above embodiment, the configuration of the action plan generation unit 45 has been mainly described, but after the autonomous driving vehicle is stopped at the first point in the first lane, the first vehicle and its rear at the second point in the second lane. When generating an action plan to merge with the second vehicle, the larger the maximum acceleration that can occur from the stopped state of the autonomous driving vehicle, the more the action if the first point is set to the vehicle traveling direction side. The configuration of the plan generation unit is not limited to that described above, and may be any. In the above embodiment, the target vehicle speed (final target vehicle speed Va) at the confluence point Pb is set to the vehicle speed of the first vehicle 201, but the vehicle speed of the second vehicle 202, the vehicle speed of the first vehicle 201, and the vehicle speed of the second vehicle 202. The target vehicle speed may be set to the average value of and the like.

The above description is merely an example, and the present invention is not limited to the above-described embodiments and modifications as long as the features of the present invention are not impaired. It is also possible to arbitrarily combine one or a plurality of the above-described embodiments and the modified examples, and it is also possible to combine the modified examples.

31 External sensor group, 40 controller, 45 action plan generation unit, 46 driving control unit, 100 autonomous driving vehicle system, 200 autonomous driving vehicle, 201 first vehicle, 202 second vehicle, 451 confluence point calculation unit, 452 maximum acceleration calculation Unit, 453 Stop point determination unit, 454 Confluence judgment unit, Pb confluence point, Pc stop point

Claims (4)

Peripheral situation detection unit that detects the surrounding situation of the autonomous driving vehicle,
An action plan generation unit that generates an action plan for the autonomous driving vehicle according to the surrounding conditions detected by the peripheral situation detection unit, and an action plan generation unit.
An autonomous vehicle system including a travel control unit that controls a traveling actuator of the autonomous vehicle according to an action plan generated by the action plan generation unit.
The action plan generation unit
While the self-driving vehicle is traveling in the first lane, the self-driving vehicle is at a confluence point between the first vehicle in the second lane and the second vehicle behind the first vehicle before reaching the stop point on the first lane. The first merging determination unit that determines whether or not merging is possible, and
When it is determined by the first merging determination unit that merging is not possible, the second merging is determined whether or not the self-driving vehicle can merge with the merging point in the second lane from the state where the autonomous vehicle is stopped at the stop point. Judgment unit and
A merging command unit that generates an action plan for merging traveling of the autonomous driving vehicle according to the determination result of the first merging determination unit and the second merging determination unit.
It has a stop point setting unit that sets the stop point, and has
In the first merging determination unit and the second merging determination unit, the distance between the first vehicle and the second vehicle after a predetermined time is equal to or more than a predetermined value, and the autonomous driving vehicle is at the merging point. When the vehicle can be reached within the predetermined time and the vehicle speed of the autonomous driving vehicle after the predetermined time can be increased to the target vehicle speed, it is determined that the vehicle can be merged at the confluence.
The self-driving vehicle system is characterized in that the stop point setting unit sets the stop point on the vehicle traveling direction side as the maximum acceleration that can be generated from the stopped state of the self-driving vehicle increases. In the self-driving vehicle system according to claim 1,
The merging command unit sets the target vehicle speed to the vehicle speed of the first vehicle assumed after the predetermined time, and generates an action plan so that the vehicle speed of the autonomous driving vehicle rises to the target vehicle speed at the merging point. Self-driving vehicle system characterized by In the self-driving vehicle system according to claim 2.
The action plan generation unit further has a merging point calculation unit that calculates the midpoint between the first vehicle and the second vehicle after the predetermined time from the present time as the merging point.
The second merging determination unit is capable of merging when the maximum mileage of the autonomous vehicle traveling at the maximum acceleration for the predetermined time is equal to or greater than the distance from the stop point to the merging point. Self-driving vehicle system characterized by determination. In the self-driving vehicle system according to any one of claims 1 to 3.
The action plan generation unit further sets a deceleration start point on the front side of the stop point in the traveling direction, and automatically sets the deceleration start point on the vehicle traveling direction side as the maximum acceleration increases. Driving vehicle system.

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