Vehicle travel control device

Abstract

To provide a vehicle travel control device capable of preventing a passenger from feeling anxious when a vehicle travels on a curve section under automatic driving.SOLUTION: A vehicle travel control device capable of performing automatic driving: acquires information on a surrounding environment of a vehicle and a vehicle state; generates a travel route on the basis of the acquired information; calculates a first speed V1 as a target speed so that lateral acceleration of the vehicle becomes equal to or lower than a predetermined value when the vehicle performs the automatic driving along the travel route; determines whether a curve section exists on the travel route; determines whether a steep slope section exists on a side of a traffic lane of a vehicle in the curve section when the same exists on the travel route; sets the target speed to a second speed V2 which is lower than a first speed V1 for the curve section when the steep slope section does not exist; and sets the target speed in the curve section to a third speed V3 which is lower than the second speed V2 when the steep slope section exists.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present invention relates to a driving control device for a vehicle capable of performing autonomous driving. [Background technology]

[0002] Vehicles that can run autonomously under the control of an automatic driving device are being developed. In vehicles that run autonomously equivalent to SAE (Society of Automotive Engineers) levels 3 to 5, the automatic driving device takes the lead in controlling the vehicle according to the level of autonomous driving. Therefore, even when driving on curved sections, the driver basically does not need to perform any driving operations. When driving on curved sections using automatic driving, there are cases where the vehicle's speed is controlled so that it runs at the same speed as on a straight road, and cases where the speed is controlled so that it runs on curved sections at a different speed than on a straight road.

[0003] As an example of speed control for an autonomous vehicle on a curved section, Patent Document 1 discloses a vehicle control device that sets a target vehicle speed for turning on a curved road and sets a target acceleration for achieving the target vehicle speed, taking into consideration the distance to the vehicle ahead and the turning radius of the curved road, etc. The device in Patent Document 1 suppresses car sickness in occupants by turning at a nearly constant acceleration from the start to the end of the turning. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2020-066383 A Summary of the Invention [Problem to be solved by the invention]

[0005] As described above, in a vehicle that performs automatic driving equivalent to levels 3 to 5, the automatic driving device of the vehicle mainly controls the vehicle, so the driver does not basically need to drive the vehicle during automatic driving, and even if the driver sits in the driver's seat, he or she is riding as a passenger, not a driver. If the behavior of the vehicle during automatic driving is different from the behavior when the driver operates the vehicle, the passengers tend to feel uncomfortable or anxious. In particular, when the vehicle runs through a curved section, the passengers are likely to feel anxious about whether the automatic driving device is properly controlling the vehicle, and this anxiety is affected by the terrain around the curved section. In particular, the anxiety increases when there is a steep slope such as a cliff around the curved section.

[0006] The present invention has been made in consideration of the above-described situation, and its purpose is to provide a vehicle driving control device that can reduce the anxiety of passengers when driving through curved sections while autonomously driving. [Means for solving the problem]

[0007] According to one aspect of the present invention, a driving control device for a vehicle capable of autonomous driving includes an environmental state acquisition unit that acquires information regarding a vehicle state and a surrounding environment of the vehicle, a route generation unit that generates a driving route during autonomous driving based on the information acquired by the environmental state acquisition unit, a curve detection unit that detects a curve section present on the driving route based on the information acquired by the environmental state acquisition unit, a steep slope area detection unit that detects a steep slope area that is present on the outside of the curve section and where the altitude drops sharply relative to the road surface of the curve section based on the information acquired by the environmental state acquisition unit, and a target speed when the vehicle is autonomously driving according to the driving route generated by the route generation unit. and a vehicle control unit that controls the speed of the vehicle so that it travels along the travel route at the target speed, wherein the target speed calculation unit calculates a first vehicle speed as the target speed so that the lateral acceleration of the vehicle is equal to or less than a predetermined value when the vehicle is autonomously travelling along the travel route, and when a curve section exists in the travel route, the target speed calculation unit sets the target speed in the curve section to a second vehicle speed that is smaller than the first vehicle speed, and when the steep slope area exists on the vehicle's travel lane side in the curve section, the target speed calculation unit sets the target speed in the curve section where the steep slope area exists to a third vehicle speed that is smaller than the second vehicle speed. Effect of the Invention

[0008] The vehicle driving control device according to the present invention can reduce the sense of anxiety felt by passengers when the vehicle is traveling through curved sections while being driven autonomously. [Brief description of the drawings]

[0009] [Figure 1] FIG. 1 is a block diagram showing a schematic configuration of a vehicle cruise control device according to a first embodiment of the present invention. [Diagram 2] 2(a) and (b) are diagrams showing schematic diagrams of curved sections. [Diagram 3]FIG. 3 is a flowchart illustrating the flow of speed control in the first embodiment. [Figure 4] FIG. 4 is a flowchart illustrating the flow of speed control in the second embodiment. [Diagram 5] FIG. 5 is a block diagram showing a schematic configuration of a vehicle driving control device according to the third embodiment of the present invention. [Figure 6] FIG. 6 is a flowchart illustrating the flow of speed control in the third embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] -First embodiment- Hereinafter, a vehicle driving control device according to a first embodiment of the present invention will be described in detail with reference to the drawings. The vehicle driving control device according to this embodiment is configured to recognize the vehicle's position and the surrounding environment of the vehicle using external sensors such as a radar and a camera, and to control the vehicle speed and steering to perform automatic driving.

[0011] Fig. 1 is a block diagram showing a schematic configuration of a vehicle cruise control device in the first embodiment, and Fig. 2(a) and (b) are diagrams showing a curve section on which the vehicle travels. The cruise control device 10 of the vehicle 1 includes an external sensor 21 that detects the environment around the vehicle, an internal sensor 22 that detects the vehicle state including the motion state, a positioning device 23 such as a Global Navigation Satellite System (GNSS), a map information database 24, an automatic driving controller 30, and a traveling module 50. In this embodiment, automatic driving of the vehicle 1 on a general road is assumed, but this embodiment can also be applied to roads other than general roads such as expressways.

[0012] The external environment sensor 21 is composed of a plurality of detection means for detecting the dividing lines on the road that define the lane in which the vehicle 1 is traveling and adjacent lanes, and the presence and relative distances of obstacles such as other vehicles and objects around the vehicle 1 as external environment data such as image data or point cloud data.

[0013] The external sensor 21 includes, for example, a plurality of cameras that capture images of the front and rear areas of the vehicle 1 using image sensors, a millimeter wave radar that transmits radio waves to the front area of ​​the vehicle 1 to detect obstacles, and a LiDAR that irradiates the front and rear areas of the vehicle with laser light to measure the distance and direction to an obstacle. Note that the external sensor 21 is not limited to the above-mentioned detection means, and may be configured to cover 360 degrees around the vehicle 1 and detect the positions and distances of obstacles, etc. within a predetermined range in the front, rear, left and right directions of the vehicle 1, and the positions of the dividing lines of the vehicle's own lane and adjacent lanes.

[0014] The internal sensor 22 is composed of a plurality of detection means for measuring physical quantities representing the motion state of the vehicle 1. The internal sensor 22 includes, for example, a vehicle speed sensor for detecting the speed of the vehicle 1, a lateral acceleration sensor for detecting the acceleration in the vehicle width direction of the vehicle 1, i.e., the lateral acceleration, a yaw rate sensor for detecting the yaw rate of the vehicle 1, an acceleration sensor for detecting the acceleration in the longitudinal direction of the vehicle 1, and the like.

[0015] The external sensor 21 and the internal sensor 22 are configured to start operating simultaneously when the vehicle 1 is started, and to constantly detect the surrounding environment and vehicle state of the vehicle 1 and transmit the information to the automatic driving controller 30.

[0016] The positioning device 23 is configured to receive radio waves from GNSS satellites and acquire current position information such as the latitude and longitude of the vehicle 1. The map information database 24 is a storage device that stores map information such as a three-dimensional high-precision map. The map information database 24 stores, in association with the position information of the road, information on the speed limit set by the road type or road signs, information on the shape of the road such as the curvature, gradient, and number of lanes, information on obstacles such as guardrails and side walls along the road, and information on steeply inclined areas around the road such as cliff-like slopes. The current position information acquired by the positioning device 23 and the map information in the map information database 24 are input to the automatic driving controller 30.

[0017] The autonomous driving controller 30 is configured, for example, by a computer including a ROM that stores programs and data, a CPU that performs arithmetic processing, a RAM that stores dynamic data and arithmetic processing results, an input / output interface, etc. The autonomous driving controller 30 is configured to execute the functions of an environmental state acquisition unit 31, a route generation unit 32, a curve detection unit 33, a target speed calculation unit 34, a vehicle control unit 35, and a steep slope area detection unit 36, and to control the entire driving control device 10 of the vehicle 1.

[0018] The environmental state acquisition unit 31 is configured to acquire information on the vehicle state and the surrounding environment of the vehicle 1. For example, the environmental state acquisition unit 31 estimates the absolute position of the vehicle 1 (the vehicle's own position) by matching the position information of the vehicle 1 input from the positioning device 23 with the map information input from the map information database 24. The environmental state acquisition unit 31 estimates the positions of the dividing lines between the own lane and adjacent lanes, the positions and speeds of other vehicles, and the like, based on external data such as image data and point cloud data input from the external sensor 21.

[0019] Furthermore, the environmental state acquisition unit 31 acquires the vehicle state including the motion state of the vehicle 1 based on the internal data input from the internal sensor 22. Note that the environmental state acquisition unit 31 can also be configured to determine the relative position of the vehicle 1 with respect to the dividing line between the adjacent lane based on the external data input from the external sensor 21, instead of estimating the absolute position of the vehicle 1 by matching the position information of the vehicle 1 with map information. Furthermore, information regarding obstacles and information regarding steeply inclined areas around the road may be acquired by the environmental state acquisition unit 31 based on the external data input from the external sensor 21, instead of or in addition to storing the information in the map information database 24.

[0020] The route generation unit 32 is configured to generate a driving route during autonomous driving based on the information acquired by the environmental state acquisition unit 31. Specifically, the route generation unit 32 generates a driving route for the vehicle 1 to travel from the vehicle position of the vehicle 1 estimated by the environmental state acquisition unit 31 to a destination of autonomous driving.

[0021] The curve detection unit 33 detects curve sections that exist on the driving route generated by the route generation unit 32. For example, the curve detection unit 33 detects whether or not a curve section exists on the driving route based on information on the road shape input from the map information database 24. The curve sections will be described later.

[0022] The steep slope area detection unit 36 ​​detects steep slope areas that exist on the outside of the curved section on the travel route. A steep slope area is an area such as a cliff where the height drops sharply from the road surface. For example, the steep slope area detection unit 36 ​​detects whether or not a steep slope area exists on the outside of the curved section on the travel route based on road information input from the map information database 24. Steep slope areas will be described later.

[0023] The target speed calculation unit 34 is configured to calculate a target speed when the vehicle 1 travels in an autonomous driving manner according to the travel route generated by the route generation unit 32. For example, the target speed calculation unit 34 calculates the target speed so that the vehicle speed is equal to or less than the speed limit of the road and based on the set speed during autonomous driving selected by the user. Specifically, the target speed calculation unit 34 calculates the target speed so that the lateral acceleration of the vehicle 1 traveling in accordance with the travel route is equal to or less than a predetermined value G1, which is equal to or less than the speed limit of the road and the speed set by the user. In addition, the target steering angle when the vehicle 1 travels in an autonomous driving manner according to the travel route generated by the route generation unit 32 is also calculated.

[0024] Here, the predetermined value G1 of the lateral acceleration is set to a value that prevents the vehicle 1 from skidding when traveling on a curved section. The lateral acceleration A when the vehicle 1 travels at a constant vehicle speed V and a constant steering angle without skidding is expressed as A=V based on the radius of curvature R of the travel route and the vehicle speed V. 2 Based on the radius of curvature R of the travel route acquired from the road information in the map information database 24, the target speed calculation unit 34 calculates the vehicle speed V at which the lateral acceleration is equal to or smaller than a predetermined value G1 (for example, G1=0.3 G) as the basic target speed V1 of the vehicle 1 traveling along the travel route.

[0025] The vehicle control unit 35 transmits a drive command to the traveling module 50 so that the vehicle 1 travels at the target speed and target steering angle calculated by the target speed calculation unit 34 according to the travel route generated by the route generation unit 32, and controls the longitudinal and lateral movements of the vehicle 1. For example, the vehicle control unit 35 calculates the yaw rate γ and lateral acceleration (d 2 y / dt 2 ) the speed, attitude, and lateral displacement of the vehicle 1 after Δt seconds are estimated from the relationship. The vehicle control unit 35 transmits to the traveling module 50 a steering angle command such that the lateral displacement after Δt seconds is yt, and a speed command such that the speed after Δt seconds is Vt.

[0026] The traveling module 50 includes a traveling actuator, a controller for controlling the traveling actuator, and the like. The traveling actuator includes a steering mechanism 51, a brake 52, and an engine 53. The traveling module 50 controls the driving of the steering mechanism 51, the brake 52, and the engine 53 based on a driving command from the vehicle control unit 35 so that the vehicle 1 travels along the traveling route at a target speed and a target steering angle. The traveling module 50 may be configured to include a traveling motor instead of or in addition to the engine 53. In this case, the vehicle 1 functions as an electric vehicle or a hybrid vehicle.

[0027] When a deceleration command is input from the vehicle control unit 35, the traveling module 50 controls the vehicle speed by controlling the braking force of the brake 52. When an acceleration / deceleration command is input from the vehicle control unit 35, the traveling module 50 controls the vehicle speed by controlling the driving force of the engine 53. In addition, when a steering command is input from the vehicle control unit 35, the traveling module 50 controls the steering mechanism 51 to perform steering control.

[0028] When there is no preceding vehicle, the automatic driving controller 30 controls the vehicle 1 to travel at a constant speed at the above-mentioned target speed. When the preceding vehicle speed is equal to or lower than the target speed and the vehicle 1 catches up with the preceding vehicle, the automatic driving controller 30 controls the vehicle 1 to travel following the preceding vehicle while maintaining a vehicle distance according to a set time gap (inter-vehicle time = vehicle distance / own vehicle speed) in accordance with the preceding vehicle speed. When the preceding vehicle speed is faster than the speed of the vehicle 1 or when the preceding vehicle has disappeared in front of the vehicle 1, the automatic driving controller 30 is configured to accelerate to the target speed at a set acceleration.

[0029] Furthermore, the automatic driving controller 30 detects lane markings and the vehicle's own position using the environmental state acquisition unit 31 based on image data acquired by the external sensor 21, for example, and performs steering control of the vehicle 1 so that the vehicle can travel in the center of the lane. The automatic driving controller 30 can estimate the vehicle's own position (self-position) by various methods and perform steering control so as to follow the travel route. As a method of self-position estimation for route tracking, in addition to white line-based self-position estimation based on lane markings (white lines) detected from image data, self-position estimation by matching point cloud data input from the external sensor 21 with a high-precision map of point clouds or a high-precision map of vector maps obtained from the map information database 24, or self-position estimation using GNSS can also be performed.

[0030] In this way, the automatic driving controller 30 performs automatic driving of the vehicle 1 by combining longitudinal control (speed control, vehicle distance control) and lateral control (steering control, lane keeping control).

[0031] Here, in a vehicle that performs automatic driving equivalent to SAE levels 3 to 5, the automatic driving device of the vehicle, i.e., the automatic driving controller 30, mainly controls the vehicle, so the driver does not basically need to drive the vehicle during automatic driving. Therefore, even if the driver sits in the driver's seat, he or she is riding as a passenger. Passengers riding in the vehicle during automatic driving tend to feel uncomfortable or anxious if the behavior of the vehicle during automatic driving differs from the behavior when the driver operates the vehicle. In particular, when the vehicle runs through a curved section, passengers are likely to feel anxious about whether the automatic driving device is controlling the vehicle appropriately, and this anxiety may be amplified by the terrain around the curved section.

[0032] As for the topography around the curved section, for example, a steep slope area where the altitude drops suddenly from the road surface is considered to affect the passenger's sense of anxiety. Here, a steep slope area is an area where the ground drops off on the outside of the road and the altitude drops suddenly compared to the altitude of the road surface of the driving lane, and includes, for example, cliffs (cliff-like slopes, cliff areas), embankments, and wharves. A steep slope area can also be said to be an area where the passenger feels that there is nothing on the outside of the road.

[0033] As an example, consider a curve section where traffic keeps to the left. Figures 2(a) and (b) show schematic diagrams of a right curve section and a left curve section where a steeply inclined area exists on the outside of the road, respectively. The right curve section CA shown in Figure 2(a) can be defined as the section from point C1 to point C2 where the road curves to the right and the curvature of the road is equal to or greater than a predetermined value. The left curve section CB shown in Figure 2(b) can be defined as the section from point C1 to point C2 where the road curves to the left and the curvature of the road is equal to or greater than a predetermined value. Point C1 is the start position of the curve section, and point C2 is the end position of the curve section.

[0034] Alternatively, the curve section may be defined based on the lateral acceleration acting on the vehicle 1. In this case, for example, when the vehicle 1 travels at a speed set by the user that is equal to or lower than the speed limit of the road, a section in which lateral acceleration exceeding a preset value occurs can be defined as the curve section. Here, the preset value of lateral acceleration for defining the curve section may be, for example, the same value as the above-mentioned predetermined value G1 of lateral acceleration, or may be a different value.

[0035] In the following explanation, the right curve section CA in the left-hand traffic zone shown in Figure 2(a) will be referred to as an outside curve section where the left lane in which vehicle 1 is traveling is the outside of the curve, and the left curve section CB in the left-hand traffic zone shown in Figure 2(b) will be referred to as an inside curve section where the left lane in which vehicle 1 is traveling is the inside of the curve. Note that in the right-hand traffic zone, the right curve section corresponds to an inside curve section where the lane in which vehicle 1 is traveling is the inside of the curve, and the left curve section corresponds to an outside curve section where the lane in which vehicle 1 is traveling is the outside of the curve.

[0036] The steep slope area D exists along the outside of the curve in the right curve section CA shown in Fig. 2(a), and along the inside of the curve in the left curve section CB shown in Fig. 2(b). In other words, the steep slope area D exists along the outside of the curve in the outside curve section CA, and along the inside of the curve in the inside curve section CB. That is, the steep slope area D exists on the driving lane side in which the vehicle 1 is traveling in the right curve section (outside curve section) CA and the left curve section (inside curve section) CB.

[0037] Information such as the position (location) of the curve section, curvature, curve start position C1, and curve end position C2 is stored as road information in the map information database 24. Also, information on steeply inclined areas D adjacent to the road is stored in the map information database 24 in association with the position information of the road. In particular, areas where the elevation suddenly drops, such as cliffs (cliff-like slopes, cliff areas), embankments, and wharves that exist on the driving lane side on the outside of the road in the curve section, are stored as steeply inclined areas D.

[0038] When driving on a curved section, a centrifugal force toward the outside of the road, i.e., lateral acceleration, acts on the vehicle. Therefore, passengers are more likely to feel uneasy when driving on a curved section than when driving on a straight road. Furthermore, it was found that when a steeply inclined area, such as a cliff D, exists along the outside of the curve, as in the right curve section CA shown in FIG. 2(a), passengers get the sensation that the cliff D on the outside of the road is approaching, and the sense of uneasiness increases compared to when the cliff D does not exist. This is thought to be because, when vehicle 1 drives in the driving lane on the outside of the curve (left lane), the passengers get the sensation that the cliff D on the outside of the road is approaching vehicle 1 due to lateral acceleration.

[0039] Also, it was found that when there is a steeply inclined area along the inside of the curve, such as cliff D, as in the left curve section CB shown in Figure 2(b), the passenger feels as if they are falling or being sucked into the cliff D on the inside of the road, and the sense of anxiety increases more than when cliff D does not exist. This is thought to be because when vehicle 1 travels in the driving lane on the inside of the curve (left lane), cliff D exists in the steering direction of vehicle 1, i.e., in the direction that vehicle 1 is facing, and therefore passengers experience the sensation that vehicle 1 is approaching cliff D on the inside of the road.

[0040] Therefore, in this embodiment, the speed control of the vehicle 1 is adjusted so as to suppress the sense of anxiety of the passengers when the vehicle 1 travels through a curved section while traveling autonomously. Specifically, the target speed when the vehicle 1 travels through a curved section while traveling autonomously is set to be smaller than the basic target speed V1 described above. Furthermore, the target speed when traveling through a curved section is made different between when a steep slope area D exists on the driving lane side in which the vehicle 1 travels in the curved section and when the steep slope area D does not exist. Specifically, the target speed when the steep slope area D exists on the driving lane side in the curved section is set to be smaller than the target speed when the steep slope area D does not exist.

[0041] As described above, the basic target speed V1 is a vehicle speed calculated based on the curvature radius R of the travel route so that the lateral acceleration is equal to or less than the predetermined value G1. For curve sections on the travel route, a target speed V1 is also set so that the lateral acceleration is equal to or less than the predetermined value G1 according to the curvature radius R. The target speed calculation unit 34 calculates the target speed V2 for the curve section, for example, by multiplying the basic target speed V1 by a first speed adjustment gain K1 set in advance. Furthermore, when a steep slope area D exists on the travel lane side of the curve section, the target speed V3 for the curve section in which the steep slope area D exists is calculated by multiplying the basic target speed V1 by a second speed adjustment gain K2 set in advance.

[0042] That is, the target speed V2 in a curve section without a steep slope area D can be expressed as K1×V1, and the target speed V3 in a curve section with a steep slope area D as K2×V1. Here, the first speed adjustment gain K1 and the second speed adjustment gain K2 are set to appropriate values ​​in advance so as to satisfy the relationship 1>K1>K2. Note that the target speed V3 in a curve section with a steep slope area D may be calculated by multiplying the target speed V2 in a curve section without a steep slope area D by a preset speed adjustment gain. The target speeds V1, V2, and V3 in curve sections with the same curvature satisfy the relationship V1>V2>V3.

[0043] Alternatively, the target speed calculation unit 34 may calculate the target speed of the curve section so that the lateral acceleration when the vehicle 1 travels through the curve section by autonomous driving is smaller than the predetermined value G1 of the lateral acceleration when calculating the basic target speed V1 described above. For example, the target speed calculation unit 34 sets the limit values ​​G2, G3 of the lateral acceleration smaller than the predetermined value G1 of the lateral acceleration for calculating the basic target speed V1. When the vehicle 1 travels through a curve section without a steep slope area D, the target speed calculation unit 34 calculates the target speed V2 so that the lateral acceleration of the vehicle 1 is equal to or smaller than a first limit value G2 smaller than the predetermined value G1, and when the vehicle 1 travels through a curve section with a steep slope area D, the target speed calculation unit 34 calculates the target speed V3 so that the lateral acceleration of the vehicle 1 is equal to or smaller than a second limit value G3 smaller than the first limit value G2. Here, the first limit value G2 and the second limit value G3 are set to appropriate values ​​in advance so as to satisfy the relationship G1>G2>G3. As a result, the target speeds V1, V2, and V3 in curve sections with the same curvature satisfy the relationship V1>V2>V3.

[0044] In this embodiment, the deceleration start position when entering a curve section with a steep slope area D is different from the deceleration start position when entering a curve section without a steep slope area D. The basic deceleration start position for decelerating to the target speed in the curve section is set to a point C3 a predetermined distance L1 before the curve start position C1 of the curve section, as shown in Figs. 2(a) and 2(b), for example. For curves with the same curvature, the target speed V3 for the curve section with the steep slope area D is smaller than the target speed V2 for the curve section without the steep slope area D. Therefore, when deceleration is started from the deceleration start position C3, the deceleration until the curve start position C1 of the curve section with the steep slope area D is reached is larger than the deceleration until the curve start position C1 of the curve section without the steep slope area D is reached, resulting in sudden braking.

[0045] Therefore, in this embodiment, the deceleration start position when entering a curve section having a steep slope area D on the driving lane side is changed to a point C4 before the point C3. The distance L2 from the curve start position C1 to the deceleration start position C4 in the curve section having the steep slope area D is longer than the distance L1 from the curve start position C1 to the deceleration start position C3 in the curve section without the steep slope area D. This makes it possible to make the deceleration when entering a curve section having the steep slope area D almost the same as the deceleration when entering a curve section having the same curvature but without the steep slope area D. In other words, the distance L2 from the curve start position C1 to the deceleration start position C4 in the curve section having the steep slope area D is set to a distance that allows deceleration to the target speed V3 at a deceleration almost the same as the deceleration required to decelerate to the target speed V2 from the deceleration start position C3 to the curve start position C1 in the curve section without the steep slope area D.

[0046] The flow of speed control by the cruise control device 10 of the vehicle 1 in this embodiment will be described in detail below with reference to the flowchart in Fig. 3. When an instruction to start autonomous driving of the vehicle 1 is given by operating a switch (not shown) or the like, the autonomous driving controller 30 starts the speed control process shown in Fig. 3.

[0047] First, in step S101, the environmental state acquisition unit 31 acquires information about the surrounding environment of the vehicle 1 and information about the vehicle state from the external sensor 21 and the internal sensor 22. In addition, the environmental state acquisition unit 31 acquires position information of the vehicle 1 from the positioning device 23, and acquires map information from the map information database 24.

[0048] In step S102, the route generation unit 32 generates a driving route for the vehicle 1 to drive autonomously from the vehicle position of the vehicle 1 to the destination, based on the information acquired in step S101.

[0049] In step S103, the target speed calculation unit 34 calculates a target speed V1 for the vehicle 1 to travel in an autonomous driving manner along the travel route generated in step S102. The target speed V1 is a vehicle speed calculated based on the curvature radius R of the travel route acquired from the road information in the map information database 24 so that the lateral acceleration is equal to or less than a predetermined value G1, and is a basic target speed that serves as a reference in autonomous driving.

[0050] In step S104, the curve detection unit 33 detects whether or not a curve section exists on the driving route generated in step S102, for example, based on road information acquired from the map information database 24. The curve detection unit 33 also acquires information on the location, curvature, start position C1, and end position C2 of the curve section. If the curve detection unit 33 detects a curve section existing on the driving route, the process proceeds to step S105, and if no curve section is detected, the process proceeds to step S109.

[0051] In step S105, the steep slope area detection unit 36 ​​detects whether a steep slope area D exists on the driving lane side on the outside of the road in the curve section, based on road information acquired from, for example, the map information database 24. Specifically, it detects whether a steep slope area D exists along the outside of the curve in a right curve section CA, as shown in Fig. 2(a), or whether a steep slope area D exists along the inside of the curve in a left curve section CB, as shown in Fig. 2(b). If a steep slope area D does not exist on the driving lane side of the curve section, the process proceeds to step S106, and if a steep slope area D exists on the driving lane side of the curve section, as shown in Fig. 2(a) or Fig. 2(b), the process proceeds to step S107.

[0052] In step S106, the target speed calculation unit 34 calculates a target speed V2 for a curve section without a steep slope area D. On the other hand, in step S107, the target speed calculation unit 34 calculates a target speed V3 for a curve section with a steep slope area D. The target speed V2 for a curve section without a steep slope area D and the target speed V3 for a curve section with a steep slope area D are smaller than the basic target speed V1, and the target speed V3 for a curve section with a steep slope area D is smaller than the target speed V2 for a curve section without a steep slope area D. Therefore, when the curvature of the curve sections is the same, the basic target speed V1, the target speed V2 for a curve section without a steep slope area D, and the target speed V3 for a curve section with a steep slope area D satisfy the relationship V1>V2>V3.

[0053] In step S108, the vehicle control unit 35 changes the deceleration start position when entering the curve section having the steep slope area D to a point C4 earlier than the point C3. As a result, the distance L2 from the curve start position C1 to the deceleration start position C4 in the curve section having the steep slope area D becomes longer than the distance L1 from the curve start position C1 to the deceleration start position C3 in the curve section without the steep slope area D.

[0054] In step S109, the vehicle control unit 35 sends a drive command to the driving module 50 so as to start deceleration from the deceleration start position C3 or C4 and drive along the driving route at the calculated target speed V1, V2 or V3, thereby performing driving control of the vehicle 1.

[0055] The cruise control device 10 for the vehicle 1 according to the first embodiment described above can achieve the following advantageous effects.

[0056] (1) The driving control device 10 of the vehicle 1 capable of performing autonomous driving includes an environmental state acquisition unit 31 that acquires information on the vehicle state and the surrounding environment of the vehicle 1, a route generation unit 32 that generates a driving route during autonomous driving based on the information acquired by the environmental state acquisition unit 31, a curve detection unit 33 that detects a curve section present on the driving route based on the information acquired by the environmental state acquisition unit 31, a steep slope area detection unit 36 ​​that detects a steep slope area D that exists on the outside of the road of the curve section and in which the altitude drops sharply relative to the road surface of the curve section based on the information acquired by the environmental state acquisition unit 31, a target speed calculation unit 34 that calculates a target speed when the vehicle 1 travels autonomously according to the driving route generated by the route generation unit 32, and a vehicle control unit 35 that controls the speed of the vehicle 1 to travel along the driving route at the target speed. The target speed calculation unit 34 calculates a first vehicle speed V1 as the target speed so that the lateral acceleration of the vehicle 1 is equal to or less than a predetermined value G1 when the vehicle 1 travels autonomously according to the driving route. When a curve section is present in the travel route, the target speed calculation unit 34 sets the target speed in the curve section to a second vehicle speed V2 which is smaller than the first vehicle speed V1, and when a steep slope area D is present on the travel lane side of the vehicle 1 in the curve section, the target speed in the curve section where the steep slope area D is present is set to a third vehicle speed V3 which is smaller than the second vehicle speed V2.

[0057] When the vehicle 1 travels through a curved section, the passenger may feel uneasy as if the vehicle 1 is being pushed outward by centrifugal force, or as if the outside of the road is approaching the vehicle 1. This feeling of uneasiness increases when a steeply inclined area D such as a cliff is present in the curved section. Therefore, by setting the target speeds V2 and V3 when the vehicle 1 travels through a curved section by autonomous driving to be smaller than the basic target speed V1, the passenger's sense of uneasiness during autonomous driving can be suppressed. Furthermore, by setting the target speed V3 in a curved section with a steeply inclined area D on the vehicle 1's driving lane side to be smaller than the target speed V2 in a curved section without a steeply inclined area D, it is possible to reliably suppress the passenger's sense of uneasiness in a curved section with a steeply inclined area D. The target speed V2 in a curve section without a steep slope area D is set to be smaller than the basic target speed V1 but larger than the target speed V3 in a curve section with a steep slope area D, so that it is possible to prevent passengers from feeling uncomfortable due to the vehicle speed being too slow in a curve section where there is no anxiety of falling into the steep slope area D.

[0058] (2) The vehicle control unit 34 is configured to start deceleration control for decelerating to a target speed in the curve section from a deceleration start position C3 set before the curve start position C1 in the curve section. The vehicle control unit 34 sets the deceleration start position C4 when entering the outside curve section CA such that a distance L2 from the curve start position C1 to the deceleration start position C4 in the curve section where a steep slope section D exists is longer than a distance L1 from the curve start position C1 to the deceleration start position C3 in a curve section where a steep slope section D does not exist.

[0059] When the curvature of the curve section is the same, the target speed V3 in the curve section where the steep slope area D exists is smaller than the target speed V2 in the curve section where the steep slope area D does not exist, so if deceleration starts from the same deceleration start position C3, sudden braking will occur in the curve section where the steep slope area D exists, which may make the passengers feel uneasy. By changing the deceleration start position C3 to point C4 in the curve section where the steep slope area D exists, the deceleration when entering the curve section where the steep slope area D exists can be made approximately the same as the deceleration when entering a curve section where the steep slope area D does not exist.

[0060] (3) The curve detection unit 33 detects curve sections present on the driving route before the start of autonomous driving based on the high-precision three-dimensional map information obtained from the map information database 24, and the steep slope area detection unit 36 ​​detects the steep slope area D before the start of autonomous driving based on the high-precision three-dimensional map information obtained from the map information database 24. This makes it possible to reduce the load caused by control processing during autonomous driving.

[0061] (4) The target speed calculation unit 34 calculates the target speed V2 by multiplying the target speed V1 by a first speed adjustment gain (first coefficient) K1, and calculates the target speed V3 by multiplying the target speed V1 by a second speed adjustment gain (second coefficient) K2 that is smaller than the first speed adjustment gain K1. By appropriately adjusting the coefficients K1 and K2, it is possible to appropriately calculate the target speed V2 in a curve section without a steep slope area D and the target speed V3 in a curve section with a steep slope area D based on the basic target speed V1.

[0062] (5) Alternatively, the target speed calculation unit 34 may calculate the target speed V2 in accordance with the curvature of the curve section so that the lateral acceleration of the vehicle 1 is equal to or less than a first limit value G2 smaller than a predetermined value G1 when the vehicle 1 travels through a curve section without a steep slope area D, and may calculate the target speed V3 in accordance with the curvature of the curve section so that the lateral acceleration of the vehicle 1 is equal to or less than a second limit value G3 smaller than the first limit value G2 when the vehicle 1 travels through a curve section with a steep slope area D. This makes it possible to appropriately calculate the target speed V2 in the curve section without a steep slope area D and the target speed V3 in the curve section with the steep slope area D from the viewpoint of the lateral acceleration acting on the vehicle 1 when traveling through the curve section.

[0063] -Second embodiment- A vehicle cruise control device according to a second embodiment of the present invention will be described below. The basic configuration of the vehicle cruise control device according to the second embodiment is similar to that of the first embodiment described above. The following mainly describes the differences from the first embodiment.

[0064] As described in the first embodiment, when traveling through a curved section, centrifugal force toward the outside of the road, i.e., lateral acceleration, acts on the vehicle. Therefore, when traveling through a right curve section CA during automatic driving, the passenger may feel uneasy as if the vehicle 1 is pushed outward of the road by centrifugal force, or the outside of the road is approaching the vehicle 1. Furthermore, if there is a steep slope section D such as a cliff adjacent to the outside of the curve in the right curve section CA, the passenger's sense of uneasiness increases. This is considered to be because the lateral acceleration acting on the vehicle 1 creates a sensation that the steep slope section D such as a cliff adjacent to the outside of the curve is approaching. If there is a steep slope section D adjacent to the outside of the curve in the right curve section CA, the sense of uneasiness is considered to be greater than if there is a steep slope section D adjacent to the inside of the curve in the left curve section CB.

[0065] Therefore, in this embodiment, the target speed when traveling through a curve section having a steep slope area D is made different between when the steep slope area D exists adjacent to the outside of the curve in the right curve section CA and when the steep slope area D exists adjacent to the inside of the curve in the left curve section CB. Specifically, the target speed when the steep slope area D exists adjacent to the outside of the curve in the right curve section CA is set to be smaller than the target speed when the steep slope area D exists on the inside of the curve in the left curve section CB.

[0066] The steep slope area detection unit 36 ​​detects, based on road information input from the map information database 24, whether the steep slope area D on the outside of the road is adjacent to the outside of the curve in the right curve section CA or adjacent to the inside of the curve in the left curve section CB.

[0067] When the steep slope area detection unit 36 ​​detects a steep slope area D adjacent to the outside of the right curve section CA on the travel route, the target speed calculation unit 34 sets the target speed in the right curve section CA including the steep slope area D to a target speed V4 smaller than the target speed V3. For example, the target speed calculation unit 34 calculates the target speed V4 in the right curve section CA including the steep slope area D by multiplying the target speed V3 in the curve section including the steep slope area D by a third speed adjustment gain K3 set in advance. That is, the target speed V4 in the right curve section CA including the steep slope area D can be expressed as V4=K3×V3. Here, the third speed adjustment gain K3 is set to an appropriate value in advance so as to satisfy the relationship 1>K3. The target speeds V3 and V4 in the curve sections having the same curvature satisfy the relationship V3>V4. For the left curve section CB including the steep slope area D, the target speed V3 in the curve section including the steep slope area D is adopted.

[0068] The flow of speed control by the cruise control device 10 of the vehicle 1 in this embodiment will be described in detail below with reference to the flowchart of Fig. 4. When an instruction to start autonomous driving of the vehicle 1 is given by operating a switch (not shown) or the like, the autonomous driving controller 30 starts the speed control process shown in Fig. 4. The processes in steps S101 to S106 shown in Fig. 4 are similar to the processes in steps S101 to S106 in the flowchart of Fig. 3, and therefore will not be described.

[0069] If it is determined in step S105 that a steep slope area D exists on the driving lane side of the curve section, the process proceeds to step S111. In step S111, it is determined whether the detected steep slope area D exists on the inside of the curve in an inside curve section (left curve section) CB or on the outside of the curve in an outside curve section (right curve section) CA. If the steep slope area D is adjacent to an inside curve section where the driving lane of the vehicle 1 is on the inside of the curve, that is, the inside of the curve in a left curve section CB in left-hand driving, the process proceeds to step S112. On the other hand, if the steep slope area D is adjacent to an outside curve section where the driving lane of the vehicle 1 is on the outside of the curve, that is, the outside of the curve in a right curve section CA in left-hand driving, the process proceeds to step S113.

[0070] In step S112, the target speed calculation unit 34 calculates a target speed V3 for the left curve section CB where the steep slope area D is present. This target speed V3 is the same as the target speed V3 for the curve section where the steep slope area D is present described above. In step S113, a target speed V4 for the right curve section CA where the steep slope area D is present is calculated. The target speed V4 for the right curve section CA where the steep slope area D is present is set to be smaller than the target speed V3 for the left curve section CB where the steep slope area D has the same curvature.

[0071] In step S108, the vehicle control unit 35 changes the deceleration start position when entering a curve section having a steep slope area D to a point C4 that is closer to the point C3. As a result, the distance L2 from the curve start position C1 to the deceleration start position C4 in the curve section having the steep slope area D becomes longer than the distance L1 from the curve start position C1 to the deceleration start position C3 in a curve section without the steep slope area D. Note that the distance from the deceleration start position C4 to the curve start position C1 when entering a right curve section CA having a steep slope area D may be set longer than the distance from the deceleration start position C4 to the curve start position C1 when entering a left curve section CB having a steep slope area D so that the vehicle can be decelerated to the target speed V3 or V4 with the same deceleration.

[0072] In step S109, the vehicle control unit 35 sends a drive command to the driving module 50 so as to start deceleration from the deceleration start position C3 or C4 and drive along the driving route at the calculated target speed V1, V2, V3, or V4, thereby performing driving control of the vehicle 1.

[0073] In the cruise control device 10 for the vehicle 1 according to the second embodiment described above, in addition to the effects of the first embodiment described above, the following operational effects can be achieved.

[0074] (1) When the curve detection unit 33 detects an outside curve section CA on the driving route where the vehicle 1's driving lane is on the outside of the curve, and the steep slope area detection unit 36 ​​detects a steep slope area D along the outside curve section CA, the target speed calculation unit 34 sets the target speed in the outside curve section CA where the steep slope area D exists to a fourth vehicle speed V4 which is smaller than the third vehicle speed V3.

[0075] In an outside curve section (right curve section) CA where the vehicle 1 is traveling in the lane on the outside of the curve, the passenger feels as if the vehicle 1 is being pushed outward from the road by centrifugal force, or as if the outside of the road is approaching the vehicle 1, which makes the passenger feel uneasy. If there is a steep slope area D on the outside of the curve in the outside curve section CA, the passenger feels as if the steep slope area D on the outside of the road is approaching due to centrifugal force, and the passenger is more likely to feel uneasy than if there is a steep slope area D on the inside of the curve in the inside curve section CB. Therefore, the target speed in the left curve section (inner curve section) CB where the steep slope area D is on the inside of the curve is set to V3, and the target speed in the right curve section (outer curve section) CA where the steep slope area D is on the outside of the curve is set to V4, which is smaller than V3. This makes it possible to suppress the passenger's sense of uneasiness in the outside curve section CA where the steep slope area D is on the outside of the curve.

[0076] -Third embodiment- A vehicle cruise control device according to a third embodiment of the present invention will be described below. The basic configuration of the vehicle cruise control device according to the third embodiment is similar to that of the first and second embodiments described above. The following mainly describes the differences from the second embodiment.

[0077] In the above-described second embodiment, the target speed when traveling through a curved section in autonomous driving is adjusted in consideration of the sense of anxiety felt by passengers when a steep slope section D is adjacent to the outside of the curve in an outside curve section (right curve section) CA. It is considered that such a sense of anxiety is alleviated when a guardrail is installed in the steep slope section D. In other words, when a guardrail is not installed in the steep slope section D of the right curve section CA, it is considered that the sense of anxiety felt by passengers is increased compared to when a guardrail is installed.

[0078] Therefore, in this embodiment, the target speed when traveling through the right curve section CA is set to be different between when a guard rail is present adjacent to the outside of the curve in the right curve section CA including the steep slope section D and when there is no guard rail. Specifically, the target speed when there is no guard rail adjacent to the outside of the curve in the right curve section CA including the steep slope section D is set to be lower than the target speed when a guard rail is present.

[0079] 5 shows a schematic configuration of the cruise control device 10A in the third embodiment. The cruise control device 10A of the vehicle 1 further has a guardrail detection unit 37. The autonomous driving controller 30A is configured to functionally execute the guardrail detection unit 37 in addition to the above-mentioned functions.

[0080] Information about guardrails present on roads is stored in association with road position information in the map information database 24. The guardrail detection unit 37 detects whether or not a guardrail exists adjacent to the outside of the curve in the right curve section CA where the steep slope section D exists, based on the road information input from the map information database 24.

[0081] When the guardrail detection unit 37 does not detect a guardrail adjacent to the outside of the right curve section CA where the steep slope area D exists, the target speed calculation unit 34 sets the target speed in the right curve section CA where the steep slope area D where no guardrail exists to a target speed V5 smaller than the target speed V4. For example, the target speed calculation unit 34 calculates the target speed V5 in the right curve section CA where the steep slope area D where no guardrail exists by multiplying the target speed V4 in the right curve section CA where the steep slope area D exists by a fourth speed adjustment gain K4 set in advance. That is, the target speed V5 in the right curve section CA where the steep slope area D where no guardrail exists can be expressed as V5=K4×V4. Here, the fourth speed adjustment gain K4 is set to an appropriate value in advance so as to satisfy the relationship 1>K4. The target speeds V4 and V5 in curve sections with the same curvature satisfy the relationship V4>V5. For the right curve section CA where the steep slope area D where a guardrail is installed, the target speed V4 in the right curve section CA where the steep slope area D exists is adopted.

[0082] The flow of speed control by the driving control device 10A of the vehicle 1 in this embodiment will be described in detail below with reference to the flowchart of Fig. 6. When an instruction to start automatic driving of the vehicle 1 is given by operating a switch (not shown) or the like, the automatic driving controller 30A starts the speed control process shown in Fig. 6. The processes in steps S101 to S112 shown in Fig. 6 are similar to the processes in steps S101 to S112 in the flowchart of Fig. 4, and therefore description thereof will be omitted.

[0083] In step S111, if it is determined that the steep slope area D is adjacent to the inside of the curve in the left curve section (inner curve section) CB, the process proceeds to step S112, and if it is determined that the steep slope area D is adjacent to the outside of the curve in the right curve section (outer curve section) CA, the process proceeds to step S121.

[0084] In step S121, the guardrail detection unit 37 detects whether or not a guardrail exists along the outside of the curve in the right curve section CA, based on road information acquired from, for example, the map information database 24. If a guardrail is installed in the right curve section CA with the steep slope section D, the process proceeds to step S122. On the other hand, if a guardrail is not installed in the right curve section CA with the steep slope section D, the process proceeds to step S123.

[0085] In step S122, the target speed calculation unit 34 calculates a target speed V4 for the right curve section CA having a steep slope area D where a guardrail is installed. This target speed V4 is the same as the target speed V4 for the right curve section CA having the steep slope area D described above. In step S123, a target speed V5 for the right curve section CA having a steep slope area D without a guardrail is calculated. The target speed V5 for the right curve section CA having a steep slope area D without a guardrail is set to be smaller than the target speed V4 for the right curve section CA having a steep slope area D with a guardrail that has the same curvature.

[0086] In step S108, the vehicle control unit 35 changes the deceleration start position when entering a curve section including the steep slope area D to point C4, which is closer to point C3. In step S109, the vehicle control unit 35 transmits a drive command to the traveling module 50 so as to start deceleration from the deceleration start position C3 or C4 and travel along the travel route at one of the calculated target speeds V1 to V5, thereby executing travel control of the vehicle 1.

[0087] In the cruise control device 10A for the vehicle 1 according to the third embodiment described above, in addition to the effects of the second embodiment described above, the following operational effects can be achieved.

[0088] The guardrail detection unit 37 is configured to detect a guardrail present on the outside of the road along the curve section based on the information acquired by the environmental state acquisition unit 31. When the guardrail detection unit 37 does not detect a guardrail along the outside curve section CA where the steep slope section D exists, the target speed calculation unit 34 sets the target speed to a fifth vehicle speed V5 lower than the fourth vehicle speed V4. When there is no guardrail adjacent to the outside of the curve in the outside curve section CA, the passenger's sense of anxiety increases compared to when there is a guardrail. By setting the target speed V5 of the outside curve section CA where there is no guardrail in the steep slope section D lower than the target speed V4 of the outside curve section CA where there is a guardrail in the steep slope section D, the passenger's sense of anxiety can be suppressed.

[0089] -Fourth embodiment- A vehicle cruise control device according to a fourth embodiment of the present invention will be described below. The basic configuration of the vehicle cruise control device according to the fourth embodiment is similar to that of the first to third embodiments described above. The following mainly describes the differences from the first embodiment.

[0090] In the above-described embodiment, the target speed is adjusted to suppress the sense of anxiety felt by the passengers when the vehicle 1 is traveling autonomously through a curved section that includes a steep slope area D, but it is considered that this sense of anxiety becomes more pronounced when the vehicle 1 is traveling in a lane adjacent to the steep slope area D. Therefore, in this embodiment, on roads that have multiple lanes traveling in the same direction, such as roads with two or more lanes on each side, the above-described adjustment of the target speed and deceleration start position is performed only when the vehicle 1 is traveling in the lane on the outermost side of the curve adjacent to the steep slope area D or the lane on the innermost side of the curve adjacent to the steep slope area D.

[0091] The environmental state acquisition unit 31 can determine whether the vehicle 1 is traveling in the outermost lane of the right curve section CA having the steep slope section D, or the innermost lane of the left curve section CB having the steep slope section D, based on external data such as image data and point cloud data input from the external sensor 21. That is, it can determine whether the vehicle 1 is traveling in the leftmost lane in a curve section where traffic is on the left. Note that even if the curve section having the steep slope section D is a road with only one lane, it can be determined that the vehicle 1 is traveling in the lane adjacent to the steep slope section D in the curve section.

[0092] When it is determined that the vehicle 1 is traveling on a lane adjacent to the steep slope area D in the curve section, the target speed calculation unit 34 calculates a target speed V3 for the curve section in which the steep slope area D exists, and the vehicle control unit 35 changes the deceleration start position when entering the curve section in which the steep slope area exists to a point C4 before the point C3. When it is determined that the vehicle 1 is traveling on a lane other than the lane adjacent to the steep slope area D in the curve section, the target speed calculation unit 34 can set, for example, the target speed V2 for the curve section without the steep slope area D as the target speed when traveling on a lane not adjacent to the steep slope area D in the curve section. Specifically, when it is determined in step S105 of the flowchart in FIG. 3 described above that the vehicle 1 is traveling on a lane adjacent to the steep slope area D in the curve section, the process proceeds to step S107. On the other hand, when it is determined that the vehicle 1 is traveling on a lane other than the lane adjacent to the steep slope area D in the curve section, or that the steep slope area D does not exist in the curve section, the process proceeds to step S106.

[0093] In the cruise control device for the vehicle 1 according to the fourth embodiment described above, in addition to the effects achieved by the first to third embodiments described above, the following operational effects can be achieved.

[0094] When a curved section on the travel route has multiple lanes, the target speed calculation unit 34 sets the target speed to the third vehicle speed V3, and the vehicle speed control unit 35 changes the deceleration start position only when the lane on which the vehicle 1 is traveling is a lane adjacent to the steep slope area D among the multiple lanes. When the curved section is a road with two or more lanes on each side, when the vehicle 1 is traveling in a lane adjacent to the steep slope area D (the lane at the left end), a strong sense of anxiety occurs that the vehicle is approaching the steep slope area D. Therefore, the sense of anxiety can be suppressed by limiting the change of the target speed and the deceleration start position to the case where the vehicle 1 is traveling in a lane adjacent to the steep slope area D in the curved section. In addition, when the vehicle 1 is traveling in other lanes that are considered to be less unsettling than the lane adjacent to the steep slope area D, the target speed and the deceleration start position are not changed, so that it is possible to suppress the discomfort felt by the occupants due to the vehicle speed in the curved section being too slow, and to minimize the impact on the total travel time of the vehicle 1 to the destination.

[0095] -Variations- (1) In the first embodiment described above, the target speed is adjusted when the vehicle 1 travels autonomously through a curved section with a steep slope area D. However, the target speed during autonomous driving may be adjusted further taking into account the gradient of the road. For example, when the curved section is downhill, it is considered that the passenger's sense of anxiety increases as the passenger may be pushed to the outside of the curve with the steep slope area D or fall into the inside of the curve with the steep slope area D. Therefore, in this embodiment, the target speed is set to be smaller on roads with a downward gradient of a predetermined percentage or more than on flat roads.

[0096] The curve section detection unit 33 can detect, based on road information acquired from the map information database 24, for example, whether or not a curve section with a steep slope area D exists on a downward gradient.

[0097] The target speed calculation unit 34 sets the above-mentioned target speed V3, for example, when the curve section with the steep slope area D is a flat road, and sets the target speed to a target speed V6 which is smaller than the target speed V3, when the curve section with the steep slope area D is a downward slope.

[0098] The target speed calculation unit 34 calculates a target speed V6 in a downward gradient curve section including a steep slope section D, for example, by multiplying the target speed V3 in the curve section including the steep slope section D by a preset fifth speed adjustment gain K5. That is, the target speed V6 in the downward gradient curve section including the steep slope section D can be expressed as: target speed V6=K5×V3. Here, the fifth speed adjustment gain K5 is preset to an appropriate value so as to satisfy the relationship 1>K5. The target speeds V3 and V6 in curve sections having the same curvature satisfy the relationship V3>V6.

[0099] In the second or third embodiment described above, the target speed during autonomous driving may be adjusted taking into account the gradient of the road. For example, when the right curve section CA in which the steep slope area D exists is a downward gradient, the target speed can be set to be smaller than when the right curve section CA in which the steep slope area D exists is a flat road. Also, for example, when the right curve section CA in which the steep slope area D without a guardrail is a downward gradient, the target speed can be set to be smaller than when the right curve section CA in which the steep slope area D without a guardrail exists is a flat road.

[0100] (2) In the above-described embodiment, the deceleration start position when entering a curve section having a steep slope area D is changed to point C4 before point C3 that is a predetermined distance L1 away from the curve start point C1. However, this is not limited to this, and the deceleration start position may be fixed to point C3 that is a predetermined distance L1 away from the curve start point C1, and the deceleration start position may not be changed. Also, instead of changing the deceleration start position when entering a curve section having a steep slope area D, a configuration may be used in which the vehicle decelerates at a constant deceleration rate when entering a curve section, regardless of whether or not there is a steep slope area D.

[0101] (3) In the above-described embodiment, the target speeds V2, V3 for the curve section without a steep slope area D and the curve section with a steep slope area D are calculated using the first and second speed adjustment gains K1, K2 or the first and second limit values ​​G2, G3 of the lateral acceleration based on the target speed V1 at which the lateral acceleration is equal to or less than a predetermined value G1. However, this is not limited to this, and the target speeds V2, V3 may be determined from speed maps for the curve section without a steep slope area D and the curve section with a steep slope area D, which are prepared in advance for each curvature.

[0102] (4) In the above-described embodiment, the curve detection unit 33 and the steep slope area detection unit 36 ​​detect whether or not a curve section exists on the driving route and whether or not a steep slope area D exists on the basis of information on the road shape input from the map information database 24, respectively, but are not limited to this. For example, the curve detection unit 33 and the steep slope area detection unit 36 ​​may be configured to detect the curve section and the steep slope area D existing on the driving route, respectively, based on external data such as image data and point cloud data input from the external sensor 21. However, as described above, by detecting the curve section and the steep slope area D before the start of autonomous driving based on high-precision three-dimensional map information acquired from the map information database 24, the load due to the control processing during autonomous driving can be suppressed. Similarly, the guardrail detection unit 37 may detect whether or not a guardrail exists along the outside of the road of the right curve section CA in which the steep slope area D exists on the driving route, based on external data such as image data and point cloud data input from the external sensor 21 instead of the road information input from the map information database 24.

[0103] Alternatively, the curve detection unit 33 may be configured to detect, as a curve section, a section in which lateral acceleration exceeding a preset value occurs when the vehicle 1 travels at a speed set by the user that is equal to or lower than the speed limit of the road. The lateral acceleration of the vehicle 1 when traveling along a travel route can be calculated based on, for example, the curvature of the road acquired by the environmental state acquisition unit 31, a target steering angle for autonomous driving, and the like. By detecting the curve section before the start of autonomous driving, the load due to the control processing during autonomous driving can be suppressed.

[0104] (5) In the above-described embodiment, the basic target speed V1, the target speed V2 for the curve section without the steep slope area D, and the target speed V3 for the curve section with the steep slope area D are set to satisfy the relationship V1>V2>V3. However, this is not limited to this, and the basic target speed V1 may be used as it is as the target speed V2 for the curve section without the steep slope area D.

[0105] (6) In the above-described third embodiment, the target speed when traveling through the right curve section CA is different depending on whether a guard rail is present in the right curve section CA having the steep slope section D or not. The target speed may be adjusted similarly for the left curve section CB having the steep slope section D. Specifically, the target speed when there is no guard rail adjacent to the inside of the curve in the left curve section CB having the steep slope section D can be set to be lower than the target speed when a guard rail is present.

[0106] Although several embodiments of the present invention have been described above, it should be noted that the present invention is not limited to the above-described embodiments, and various modifications and variations are possible within the scope of the present invention. [Explanation of symbols]

[0107] 1 vehicle 10,10A Driving control device 24 Map information database 30,30A Automatic Operation Controller 31 Environmental status acquisition unit 32 Route Generation Unit 33 Curve detection section 34 Target speed calculation section 35 Vehicle control unit 36 Steep slope area detection unit 37 Guardrail detector C1 Curve start position C3,C4 Deceleration start position D Steep slope area G1 Lateral acceleration preset value G2,G3 1st and 2nd limit values K1~K5 1st to 5th speed adjustment gain

Claims

1. A vehicle driving control device capable of performing autonomous driving, an environmental state acquisition unit that acquires information regarding a vehicle state and a surrounding environment of the vehicle; A route generation unit that generates a driving route during autonomous driving based on the information acquired by the environmental state acquisition unit; a curve detection unit that detects a curve section present on the travel route based on the information acquired by the environmental state acquisition unit; a steep slope area detection unit that detects a steep slope area that exists on the outer side of the curve section of the road and where the altitude drops sharply with respect to the road surface of the curve section based on the information acquired by the environmental state acquisition unit; a target speed calculation unit that calculates a target speed when the vehicle travels autonomously along the travel route generated by the route generation unit; a vehicle control unit that controls a speed of the vehicle so that the vehicle travels along the travel route at the target speed; Equipped with the target speed calculation unit calculates a first vehicle speed as the target speed such that a lateral acceleration of the vehicle is equal to or less than a predetermined value when the vehicle is autonomously driven along the travel route; the target speed calculation unit, when a curve section is present in the travel route, sets the target speed in the curve section to a second vehicle speed that is lower than the first vehicle speed; The target speed calculation unit, when the steep slope area exists on the vehicle's driving lane side in the curve section, sets the target speed in the curve section where the steep slope area exists to a third vehicle speed which is smaller than the second vehicle speed.

2. 2. The vehicle driving control device according to claim 1, wherein when the curve detection unit detects an outside curve section in the driving route in which the vehicle's driving lane is on the outside of the curve, and the steep slope area detection unit detects the steep slope area along the outside curve section, the target speed calculation unit sets the target speed in the outside curve section in which the steep slope area exists to a fourth vehicle speed that is smaller than the third vehicle speed.

3. a guardrail detection unit that detects a guardrail that is present on an outer side of a road along the curve section based on the information acquired by the environmental state acquisition unit, 3. The vehicle driving control device according to claim 2, wherein when the guardrail detection unit does not detect the guardrail along the outer curve section in which the steep slope area exists, the target speed calculation unit sets the target speed to a fifth vehicle speed which is lower than the fourth vehicle speed.

4. the vehicle control unit is configured to start deceleration control for decelerating the vehicle to the target speed in the curve section from a deceleration start position that is set before a start position of the curve section, 4. The vehicle driving control device according to claim 1, wherein the vehicle control unit changes the deceleration start position when entering the curve section such that a distance from a start position of the curve section in which the steep slope area exists to the deceleration start position is longer than a distance from a start position of the curve section in which the steep slope area does not exist to the deceleration start position.

5. 5. The vehicle driving control device according to claim 4, wherein, when the curve section on the driving route has a plurality of lanes, the target speed calculation unit sets the target speed to the third vehicle speed, and the vehicle speed control unit changes the deceleration start position only when the lane on which the vehicle is traveling is one of the plurality of lanes adjacent to the steep slope area.

6. the curve detection unit detects the curve section present on the driving route before the autonomous driving starts, based on high-precision three-dimensional map information obtained from a map information database; The vehicle driving control device according to claim 1 , wherein the steep slope area detection unit detects the steep slope area before the autonomous driving starts, based on the high-precision three-dimensional map information.

7. The target speed calculation unit Calculating the second vehicle speed by multiplying the first vehicle speed by a first coefficient; The vehicle cruise control device according to claim 1 , wherein the third vehicle speed is calculated by multiplying the first vehicle speed by a second coefficient that is smaller than the first coefficient.

8. The target speed calculation unit calculating the second vehicle speed in accordance with a curvature of the curve section such that a lateral acceleration of the vehicle is equal to or less than a first limit value that is smaller than the predetermined value when the vehicle travels through the curve section; 2. The vehicle driving control device according to claim 1, wherein when the vehicle travels through the curve section in which the steep slope section exists, the third vehicle speed is calculated in accordance with a curvature of the curve section so that the lateral acceleration of the vehicle is equal to or less than a second limit value that is smaller than the first limit value.

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