JP2020163969A - Vehicle drive assisting system - Google Patents

Abstract

To provide a vehicle drive assisting system that is able to achieve both evaluation accuracy of a route cost of a route candidate and reduction of the calculation load thereof.SOLUTION: A vehicle drive assisting system 100 comprises an ECU 10, which is a control device. On the basis of travel road information, the ECU 10 sets a target route on a travel road, and controls a vehicle 1 such that it travels along the target route. The ECU 10 sets sampling points SP at intervals d1 along a portion near a meeting position MP where a plurality of traffic lanes meet, among route candidates RC, and sets sampling points SP at intervals d2 larger than the interval d1 along the other portion thereof.SELECTED DRAWING: Figure 3

Description

The present invention relates to a vehicle driving support system mounted on a vehicle.

Potential method, spline interpolation function, A star (A *), RRT, state lattice method, etc. are known as algorithms used for setting a vehicle route candidate (that is, a candidate that can be a target route for actually driving a vehicle). ing. In addition, a vehicle driving support system using such an algorithm has also been proposed.

According to the above algorithm, it is possible to set a plurality of route candidates on the travel path of the vehicle. The route cost of each route candidate is calculated from the viewpoint of obstacle avoidance and the like, and one route candidate determined to be appropriate based on the calculation result is selected as the target route. For example, Patent Document 1 discloses a vehicle driving support system in which a plurality of route candidates are set on a grid map and one route candidate is selected based on a movement cost.

International Publication No. 2013/05/1081

The system described in Patent Document 1 calculates the movement cost in all the cells through which the route candidate passes among the plurality of cells of the grid map. Although the method of calculating the route cost at a large number of positions on the route candidate is significant from the viewpoint of improving the evaluation accuracy of the route cost of the route candidate, it entails a large calculation load.

In particular, when a method capable of setting a large number of route candidates such as the state lattice method is used, the calculation load of the route cost may become enormous. Therefore, it has been required to reduce the calculation load and to achieve the evaluation accuracy of the route cost at the same time.

The present invention has been made to solve such a problem, and an object of the present invention is to provide a vehicle driving support system capable of achieving both evaluation accuracy of a route cost of a route candidate and reduction of the calculation load thereof. To do.

In order to solve the above problems, the present invention is a vehicle driving support system mounted on a vehicle, which is a travel path information acquisition device for acquiring travel path information related to a travel path, and a travel path based on the travel path information. A control device for setting a target route and controlling the vehicle so as to travel along the target route is provided, and the control device sets a plurality of route candidates on the travel route based on the travel route information, and a plurality of route candidates are set. A plurality of sampling points are set at predetermined intervals along each of the route candidates, the route cost at each of the plurality of sampling points is calculated, and one route candidate is selected as a target route from the plurality of route candidates based on the route cost. In addition, the controller sets sampling points at first intervals along the portion of the route candidate near the confluence where multiple lanes merge with each other, and along the other portion. It is characterized in that the sampling points are set at the second interval, which is larger than the first interval.

In the vicinity of the confluence where a plurality of lanes merge with each other, the traveling directions of vehicles traveling in each lane intersect with each other, increasing the possibility of vehicles colliding with each other. The vehicle driving support system needs to pay more attention to safety when the vehicle is driven in the vicinity of such a confluence.

According to the above configuration, the control device sets sampling points at the first interval along the portion of the route candidates near the confluence. Since the first interval is smaller than the second interval, a plurality of sampling points are set at a relatively high density in the vicinity of the confluence. As a result, the evaluation accuracy of the route cost in the vicinity of the confluence is made high, and the vehicle can be safely driven in the vicinity of the confluence.

On the other hand, for the other portion of the route candidate (that is, the portion excluding the portion near the confluence portion), the control device sets sampling points at the second interval along the other portion. Since the second interval is larger than the first interval, a plurality of sampling points are set in the other portion at a relatively low density. As a result, it becomes possible to reduce the calculation load of the route cost in the other part. Since the density of sampling points is relatively low, the evaluation accuracy of the route cost in the other part is also low, but the influence of the evaluation accuracy on the running of the vehicle in the vicinity of the confluence is relatively small.

That is, according to the above configuration, it is possible to make the evaluation accuracy of the route cost practically sufficient while reducing the calculation load. As a result, it is possible to achieve both the evaluation accuracy of the route cost of the route candidate and the reduction of the calculation load thereof.

In the present invention, preferably, the control device sets a detour route candidate which is a route candidate for bypassing the confluence portion, and among the detour route candidates, sampling points at the first interval along a portion near the confluence portion. Is set, and sampling points are set at the second interval along the other parts.
According to this configuration, by setting a detour route candidate, it is possible to drive the vehicle so as to bypass the confluence part in order to ensure safety. Further, by setting sampling points at the first interval and the second interval for the detour route candidate, it is possible to achieve both the evaluation accuracy of the route cost and the reduction of the calculation load for the detour route candidate.

In the present invention, preferably, the control device is configured so that the closer the route candidate is to the confluence, the larger the portion of the route candidate for which the sampling point is set at the first interval.
According to this configuration, the sampling points are preferentially set for the route candidates close to the confluence portion, and it is possible to achieve both the evaluation accuracy of the route cost and the reduction of the calculation load thereof.

It should be noted that the portion of the route candidates in which the sampling points are set at the first interval does not need to be continuously increased in accordance with the distance to the confluence portion. For example, a form in which the portion gradually increases in proportion to the distance to the confluence is also included in the scope of the present invention.

In the present invention, preferably, the control device is configured so that the higher the moving speed of the vehicle, the larger the portion of the route candidates for which the sampling points are set at the first interval.
The higher the moving speed of the vehicle, the more attention must be paid to safety when traveling the vehicle in the vicinity of the confluence. According to the above configuration, the control device increases the portion of the route candidates in which the sampling points are set at the first interval as the moving speed of the vehicle increases. As a result, the evaluation accuracy of the route cost in the vicinity of the confluence is made high, and the vehicle can be safely driven in the vicinity of the confluence.

It should be noted that the portion of the route candidates in which the sampling points are set at the first interval does not need to be continuously increased as the moving speed of the vehicle increases. For example, a form in which the portion gradually increases as the moving speed of the vehicle increases is also included in the scope of the present invention.

According to the present invention, it is possible to provide a vehicle driving support system capable of achieving both the evaluation accuracy of the route cost of a route candidate and the reduction of the calculation load thereof.

It is a block diagram of the vehicle driving support system which concerns on embodiment. It is explanatory drawing of a route candidate and a sampling point. It is explanatory drawing of a route candidate and a sampling point. It is explanatory drawing of a route candidate and a sampling point. It is a flowchart which shows the calculation performed by the ECU of FIG.

Hereinafter, embodiments will be described with reference to the accompanying drawings. In order to facilitate understanding of the description, the same components are designated by the same reference numerals in each drawing, and duplicate description is omitted.

First, the outline of the vehicle driving support system 100 according to the present invention will be described with reference to FIGS. 1 and 2. FIG. 1 is a configuration diagram of a vehicle driving support system 100. FIG. 2 is an explanatory diagram of a route candidate RC and a sampling point SP.

The vehicle driving support system 100 is mounted on the vehicle 1 and provides driving support control for driving the vehicle 1 along a target route. As shown in FIG. 1, the vehicle driving support system 100 includes an ECU (electronic control unit) 10, a plurality of sensors, and a plurality of control systems. The plurality of sensors include a camera 21, a radar 22, a vehicle speed sensor 23 for detecting the behavior of the vehicle 1 and a driving operation by an occupant, an acceleration sensor 24, a yaw rate sensor 25, a steering angle sensor 26, an accelerator sensor 27, and a brake. A sensor 28 is included. Further, the plurality of sensors include a positioning system 29 and a navigation system 30 for detecting the position of the vehicle 1. The plurality of control systems include an engine control system 31, a brake control system 32, and a steering control system 33.

Other sensors include a peripheral sonar that measures the distance and position of the peripheral structure with respect to the vehicle 1, a corner radar that measures the approach of the peripheral structure at the four corners of the vehicle 1, and a vehicle interior of the vehicle 1. An inner camera for shooting the image may be included.

The ECU 10 is an example of a control device according to the present invention. The ECU 10 is composed of a computer including a CPU, a memory for storing various programs, an input / output device, and the like. The ECU 10 executes various calculations based on signals received from a plurality of sensors, and appropriately sets the engine system, brake system, and steering system for the engine control system 31, brake control system 32, and steering control system 33, respectively. Sends a control signal to activate the system.

The ECU 10 performs an operation for specifying a position on the travel path based on the travel path information. The travel path information is information on the travel path on which the vehicle 1 is traveling, and includes, for example, information on the shape of the travel path (straight line, curve, curve curvature), travel path width, number of lanes, lane width, and the like. .. The travel path information is acquired by the camera 21, the radar 22, the navigation system 30, and the like.

FIG. 2 shows how the vehicle 1 is traveling on the travel path 5. The ECU 10 sets a plurality of virtual grid points G _n (n = 1, 2, ... N) on the traveling path 5 existing in the traveling direction of the vehicle 1 by calculation based on the traveling path information. When the direction in which the travel path 5 extends is defined as the x direction and the width direction of the travel path 5 is defined as the y direction, the grid points G _n are arranged in a grid pattern along the x direction and the y direction.

The range in which the ECU 10 sets the grid point G _n extends in front of the vehicle 1 by a distance L along the travel path 5. The distance L is calculated based on the speed of the vehicle 1 at the time of executing the calculation. In the present embodiment, the distance L is a distance (L = V × t) that is expected to travel in a predetermined fixed time t (for example, 3 seconds) at the speed (V) at the time of executing the calculation. However, the distance L may be a predetermined fixed distance (eg, 100 m) or a function of velocity (and acceleration). Further, the width W of the range in which the grid point G _n is set is set to a value substantially equal to the width of the traveling path 5. By setting a plurality of grid points G _{n in} this way, it is possible to specify the position on the travel path 5.

Since the traveling path 5 shown in FIG. 2 is a straight section, the grid points G _n are arranged in a rectangular shape. However, since the grid points G _n are arranged along the direction in which the running path extends, when the traveling path includes a curve section, the grid points G _n are arranged along the curvature of the curve section.

Further, the ECU 10 executes an operation for setting a route candidate RC (that is, a candidate that can be a target route for actually traveling the vehicle 1) based on the travel path information and the obstacle information. Obstacle information includes the presence or absence of obstacles (for example, preceding vehicles, parked vehicles, pedestrians, falling objects, etc.) on the traveling path 5 in the traveling direction of the vehicle 1, its type, size, moving direction, moving speed, and the like. Information about. Obstacle information is acquired by the camera 21 and the radar 22.

The ECU 10 sets a plurality of route candidate RCs by route search using the state lattice method. According to the state lattice method, a plurality of route candidate RCs extending from the starting point P _s while branching toward each grid point G _n existing in the traveling direction of the vehicle 1 are set. The start point P _s is the position of the vehicle 1 at the time of executing the calculation. In the example shown in FIG. 2, since the vehicle 1 is located at the origin of the xy coordinates, the coordinates of the start point P _s are (0,0). The ECU 10 defines a multi-order function in which the y-coordinate has the x-coordinate as a variable, and sets a curve drawn in the xy-coordinate based on the multi-order function as a route candidate RC. The polymorphic function is, for example, a quintic function or a cubic function. FIG. 2 shows route candidates RC _a , RC _b , and RC _c that are a part of a plurality of route candidate RCs set by the ECU 10.

Further, the ECU 10 selects one route candidate RC having the minimum route cost from the plurality of route candidate RCs. Specifically, first, the ECU 10 sets a plurality of sampling points SP along each route candidate RC as shown in FIG. A plurality of sampling points SP are arranged on each route candidate RC at intervals from each other. As an example, FIG. 2 shows sampling points SP set at equal intervals along the entire route candidates RC _a , RC _b , and RC _c .

Next, the ECU 10 calculates the path cost at each sampling point SP. Further, the ECU 10 adds up the route costs at the sampling points SP set along the route candidate RC for each route candidate RC, and divides the total value by the total length of the route candidate RC. The ECU 10 uses the value obtained by the division as the route cost of the route candidate RC. The ECU 10 selects the route candidate RC having the minimum route cost from the plurality of route candidate RCs and sets it as the target route.

Further, the ECU 10 sets the control amount of the speed control and the steering control of the vehicle 1 at each sampling point. The control amount is set based on the speed and steering required to drive the vehicle 1 along the target route, and is also used for calculating the route cost. The ECU 10 transmits a control signal to the engine control system 31, the brake control system 32, and the steering control system 33 based on the control amount.

The camera 21 is an example of a travel path information acquisition device according to the present invention. The camera 21 photographs the surroundings of the vehicle 1 and outputs image data. Based on the image data received from the camera 21, the ECU 10 has an object (for example, a preceding vehicle, a parked vehicle, a pedestrian, a driving path, a lane marking (lane boundary line, a white line, a yellow line), a traffic signal, a traffic sign, Identify stop lines, intersections, etc.). Further, when the object is a vehicle, the ECU 10 specifies the type (large vehicle, passenger vehicle, etc.). The ECU 10 may acquire information on the target object from the outside through transportation infrastructure, vehicle-to-vehicle communication, or the like. Thereby, the type, relative position, moving direction, etc. of the object are specified.

The radar 22 is an example of a travel path information acquisition device according to the present invention. The radar 22 measures the position and speed of an object (particularly, a preceding vehicle, a parked vehicle, a pedestrian, a falling object on the traveling path 5, etc.). As the radar 22, for example, a millimeter wave radar can be used. The radar 22 transmits radio waves in the traveling direction of the vehicle 1, and receives the reflected waves generated by reflecting the transmitted waves by the object. Then, the radar 22 measures the distance between the vehicle 1 and the object (for example, the inter-vehicle distance) and the relative speed of the object with respect to the vehicle 1 based on the transmitted wave and the received wave. In this embodiment, instead of the radar 22, a laser radar, an ultrasonic sensor, or the like may be used to measure the distance to the object and the relative speed. Further, a position and speed measuring device may be configured by using a plurality of sensors.

The vehicle speed sensor 23 detects the absolute speed of the vehicle 1. The acceleration sensor 24 detects the acceleration of the vehicle 1 (vertical acceleration / deceleration in the front-rear direction, lateral acceleration / deceleration in the horizontal direction). The yaw rate sensor 25 detects the yaw rate of the vehicle 1. The steering angle sensor 26 detects the rotation angle (steering angle) of the steering wheel of the vehicle 1. The accelerator sensor 27 detects the amount of depression of the accelerator pedal. The brake sensor 28 detects the amount of depression of the brake pedal.

The positioning system 29 is a GPS system and / or a gyro system, and detects the position of the vehicle 1 (current vehicle position information). The navigation system 30 stores the map information inside, and can provide the map information to the ECU 10. The ECU 10 identifies roads, intersections, traffic signals, buildings, etc. existing around the vehicle 1 (particularly, the traveling direction) based on the map information and the current vehicle position information. The map information may be stored in the ECU 10.

The engine control system 31 controls the engine of the vehicle 1. When it is necessary to accelerate or decelerate the vehicle 1, the ECU 10 transmits a control signal to the engine control system 31 in order to change the engine output.

The brake control system 32 controls the brake device of the vehicle 1. When it is necessary to decelerate the vehicle 1, the ECU 10 transmits a control signal to the brake control system 32 in order to generate a braking force.

The steering control system 33 controls the steering device of the vehicle 1. When it is necessary to change the traveling direction of the vehicle 1, the ECU 10 transmits a control signal to the steering control system 33 to change the steering direction.

Next, the calculation for setting the sampling point SP will be described with reference to FIGS. 3 and 4. 3 and 4 are explanatory views of the route candidate RC and the sampling point SP.

As described above, the ECU 10 sets a plurality of sampling points SP along each route candidate RC. As the number of sampling points SP to be set increases, the evaluation accuracy of the route cost of each route candidate RC increases, but the calculation load increases and the practicality is impaired. Therefore, the ECU 10 sets the sampling point SP based on the confluence portion MP in order to achieve both the evaluation accuracy of the path cost and the reduction of the calculation load. Hereinafter, a method of setting the sampling point SP will be described.

FIG. 3 shows a route candidate RC and a sampling point SP when the vehicle 1 is traveling in the lane 51a of the traveling path 51. Running path 51 has a lane 51 a - 51 c, lane 51a and lane 51b are joined to each other at the merging portion MP _1. In other words, the width of the lane 51b gradually decreases in the vicinity of the confluence MP ₁ so as to guide the other vehicle 91 from the lane 51b to the lane 51a. The ECU 10 (see FIG. 1) intends to drive the vehicle 1 so as to pass by the side of the confluence MP ₁ .

By the route search using the state lattice method described above, route candidates RC _{1 to} RC ₃ are set in the traveling path 51. The route candidates RC ₂ and RC ₃ are examples of detour route candidates according to the present invention, and when the vehicle 1 bypasses the confluence MP ₁ (for example, when avoiding a collision between the vehicle 1 and another vehicle 91). It can be a target route.

The ECU 10 sets a sampling point SP at an interval d ₁ along a portion of each of the route candidates RC _{1 to} RC ₃ in the vicinity of the vehicle 1. The interval d ₁ is an example of the first interval according to the present invention. Specifically, the ECU 10 sets the sampling point SP at the interval d ₁ along the first portions RC ₁₁ , RC ₂₁ , and RC ₃₁ of the route candidates RC _{1 to} RC ₃ . The first part RC ₁₁ , RC ₂₁ , and RC ₃₁ extend from the vehicle 1 in the x direction (see FIG. 2) by a length L ₁ (for example, 10 m). The ECU 10 sets the length L ₁ larger as the moving speed of the vehicle 1 increases.

The route candidate RC ₁ is the closest to the confluence MP ₁ among the route candidates RC _{1 to} RC ₃ . The ECU 10 sets the sampling point SP at the interval d ₁ along the portion of the route candidate RC ₁ in the vicinity of the confluence portion MP ₁ . Specifically, the ECU 10 sets the sampling point SP at the interval d ₁ along the second portion RC ₁₂ of the route candidate RC ₁ . The second portion RC ₁₂ extends by a length L ₂₁ (for example, 15 m) in the x direction in the vicinity of the confluence MP ₁ . The ECU 10 sets the length L ₂₁ larger as the moving speed of the vehicle 1 increases.

Path candidate RC ₂ is closer to the merging portion MP ₁ Following the path candidate RC ₁ in path candidate RC ₁ to RC _5. The ECU 10 sets the sampling point SP at the interval d ₁ along the portion of the route candidate RC ₂ in the vicinity of the confluence portion MP ₁ . Specifically, the ECU 10 sets the sampling point SP at the interval d ₁ along the second portion RC ₂₂ of the route candidate RC ₂ . The second portion RC ₂₂ extends by a length L ₂₂ (for example, 10 m) in the x direction in the vicinity of the confluence MP ₁ . The ECU 10 sets the length L ₂₂ larger as the moving speed of the vehicle 1 increases.

Further, the ECU 10 sets a sampling point SP at an interval d ₂ along a portion of the route candidates RC ₁ and RC ₂ excluding both the first portion RC ₁₁ , RC ₂₁ and the second portion RC ₁₂ and RC _22. Set. The interval d ₂ is an example of the second interval according to the present invention.

The interval d ₂ is larger than the interval d ₁ (for example, d ₁ = 0.2 m, d ₂ = 2.0 m). Therefore, the sampling point SP is set at a relatively high density along the first part RC ₁₁ , RC ₂₁ and the second part RC ₁₂ , RC ₂₂ , and the sampling point SP is set at a relatively low density along the other parts. Set. In other words, the number of sampling points SP per unit length in the first part RC ₁₁ , RC ₂₁ and the second part RC ₁₂ , RC ₂₂ is larger than that in the other parts. Further, among the route candidates RC ₁ and RC ₂ , in the portion excluding the second portions RC ₁₂ and RC ₂₂ , the interval for setting the sampling point SP increases as the vehicle 1 separates from the vehicle 1 in the traveling direction. It increases from d ₁ to d ₂ .

Further, the length of the second portion RC ₁₂ of the route candidate RC ₁ is larger than the length of the second portion RC ₂₂ of the route candidate RC ₂ . Therefore, the number of sampling points SP set in the second portion RC ₁₂ of the route candidate RC ₁ is larger than the number of sampling points SP set in the second portion RC ₂₂ of the route candidate RC ₂ .

Meanwhile, ECU 10, of the farthest path candidates RC ₃ from the confluent portion MP ₁ in path candidate RC ₁ to RC _3, along a portion excluding the portion in the vicinity of the vehicle 1, sampling points SP at intervals d ₂ To set.

FIG. 4 shows a route candidate RC and a sampling point SP when the vehicle 1 is traveling in the lane 52a of the traveling path 52. The traveling path 52 has lanes 52a and 52b. On the side of the running path 52 extends the travel path 53 having a lane 53a, lane 52a and the lane 53a are joined to each other at the merging portion MP _2. In other words, the width of the lane 53a gradually decreases in the vicinity of the confluence MP ₂ so as to guide the other vehicle 92 from the lane 53a to the lane 52a. The ECU 10 (see FIG. 1) intends to drive the vehicle 1 so as to pass by the side of the confluence MP ₂ .

By the route search using the state lattice method described above, route candidates RC _{4 to} RC ₆ are set on the traveling path 52. The route candidates RC ₅ and RC ₆ are examples of detour route candidates according to the present invention, and when the vehicle 1 travels while bypassing the confluence MP ₂ (for example, avoiding a collision between the vehicle 1 and another vehicle 92). If) can be the target route.

The ECU 10 sets the sampling point SP at the interval d ₁ along the portion of each of the route candidates RC _{4 to} RC ₆ in the vicinity of the vehicle 1. Specifically, the ECU 10 sets sampling points SP at intervals d ₁ along the first portions RC ₄₁ , RC ₅₁ , and RC ₆₁ of the route candidates RC ₄ , RC ₅ , and RC ₆ . The first part RC ₄₁ , RC ₅₁ , RC ₆₁ extends from the vehicle 1 in the x direction (see FIG. 2) by a length L ₁ .

The route candidate RC ₄ is the closest to the confluence MP ₂ among the route candidates RC _{4 to} RC ₆ . The ECU 10 sets the sampling point SP at the interval d ₁ along the portion of the route candidate RC ₄ in the vicinity of the confluence portion MP ₂ . Specifically, the ECU 10 sets the sampling point SP at the interval d ₁ along the second portion RC ₄₂ of the route candidate RC ₄ . The second portion RC ₄₂ extends by a length L ₃₁ (for example, 15 m) in the x direction in the vicinity of the confluence MP ₂ . The ECU 10 sets the length L ₃₁ larger as the moving speed of the vehicle 1 increases.

Path candidate RC ₅ is closer to the merging portion MP ₂ Following path candidates RC ₄ in the path candidates RC ₄ to RC _6. The ECU 10 sets the sampling point SP at the interval d ₁ along the portion of the route candidate RC ₅ near the confluence MP ₂ . Specifically, the ECU 10 sets the sampling point SP at the interval d ₁ along the second portion RC ₅₂ of the route candidate RC ₅ . The second portion RC ₅₂ extends by a length L ₃₂ (for example, 10 m) in the x direction in the vicinity of the confluence MP ₂ . The ECU 10 sets the length L ₃₂ larger as the moving speed of the vehicle 1 increases.

Further, the ECU 10 sets a sampling point SP at an interval d ₂ along a portion of the route candidates RC ₄ and RC ₅ excluding both the first portion RC ₄₁ and RC ₅₁ and the second portion RC ₄₂ and RC _52. Set.

As mentioned above, since the interval d ₂ is larger than the interval d _{1, the} density is relatively high along the first parts RC ₄₁ and RC ₅₁ and the second parts RC ₄₂ and RC ₅₂ of the route candidates RC ₄ and RC ₅ . The sampling point SP is set at, and the sampling point SP is set at a relatively low density along the other parts. In other words, the number of sampling points SP per unit length in the first part RC ₄₁ , RC ₅₁ and the second part RC ₄₂ , RC ₅₂ is larger than that in the other parts. In addition, among the route candidates RC ₄ and RC ₅ , in the portion excluding the second part RC ₄₂ and RC ₅₂ , the interval for setting the sampling point SP is increased as the vehicle 1 is separated from the vehicle 1 in the traveling direction. It increases from d ₁ to d ₂ .

Further, the length of the second portion RC ₄₂ of the route candidate RC ₄ is larger than the length of the second portion RC ₅₂ of the route candidate RC ₅ . Therefore, the number of sampling points SP set in the second portion RC ₄₂ of the route candidate RC ₄ is larger than the number of sampling points SP set in the second portion RC ₅₂ of the route candidate RC ₅ .

Meanwhile, ECU 10, of the farthest path candidates RC ₆ from the confluent portion MP ₂ in path candidates RC ₄ to RC _6, along a portion excluding the portion in the vicinity of the vehicle 1, sampling points SP at intervals d ₂ To set.

As can be understood from FIGS. 3 and 4, the ECU 10 preferentially sets the sampling point SP in the vicinity of the merging portions MP ₁ and MP _{2 and in} the vicinity of the vehicle 1. In other words, the ECU 10 thins out the sampling points SP in the portion of the route candidate RC excluding both the portion near the merging portions MP ₁ and MP ₂ and the portion near the vehicle 1. As a result, it is possible to reduce the calculation load of the route cost in other parts while improving the evaluation accuracy of the route cost in the vicinity of the merging portions MP ₁ and MP _{2 and} the vicinity of the vehicle 1. That is, it is possible to achieve both reduction of the calculation load and evaluation accuracy of the route cost.

Next, with reference to FIG. 5, the calculation executed when the ECU 10 provides the driving support control will be described. FIG. 5 is a flowchart showing an operation executed by the ECU 10. The ECU 10 repeatedly executes the calculation shown in FIG. 5 (for example, every 0.05 to 0.2 seconds).

First, in step S1, the ECU 10 acquires travel path information from the camera 21, the radar 22, and the navigation system 30 (see FIG. 1).

Next, in step S2, the ECU 10 specifies the shape of the travel path (for example, the direction in which the travel path extends, the width of the travel path, etc.) based on the travel path information, and a plurality of grid points G _n on the travel path. (N = 1, 2, ... N) is set. The ECU 10 sets grid points G _n every 10 m in the x direction (see FIG. 2) and every 0.875 m in the y direction (see FIG. 2), for example.

Next, in step S3, the ECU 10 acquires obstacle information from the camera 21 and the radar 22. That is, the ECU 10 acquires information on the presence / absence of obstacles on the traveling path in the traveling direction of the vehicle 1, the type of obstacles, the moving direction of the obstacles, the moving speed, and the like.

Next, in step S4, the ECU 10 sets a plurality of route candidate RCs on the traveling path. Specifically, the ECU 10 defines curves extending from the start point P _s (see FIG. 2), which is the position of the vehicle 1 at the time of executing the calculation, to each grid point G _n set in step S2, and routes these curves. Set as a candidate RC.

Step S5 includes setting the sampling point SP (steps S5a to 5d) and calculating the route cost (step S5e).

In step 5a, the ECU 10 sets the sampling point SP at the interval d ₁ along the portion of the route candidate RC near the vehicle 1. Here, the sampling point SP is set along the portion of the route candidate RC extending from the vehicle 1 in the x direction (see FIG. 2) by a length L ₁ (see FIGS. 3 and 4). The ECU 10 sets the length L ₁ larger as the moving speed of the vehicle 1 increases.

Next, in step S5b, the ECU 10 determines whether or not the route candidate RC is in the vicinity of the merging portion MP. For example, the ECU 10 may determine whether or not the route candidate RC is in the vicinity of the confluence portion MP based on whether or not the distance from the confluence portion MP to the route candidate RC is larger than a predetermined threshold value. When it is determined that the route candidate RC is in the vicinity of the merging portion MP (S5b: YES), the ECU 10 proceeds to step S5c.

Next, in step S5c, the ECU 10 sets the sampling point SP at the interval d ₁ along the portion of the route candidate RC near the confluence MP. Here, the sampling point SP is set at the interval d ₁ along the portion of the route candidate RC extending in the x direction near the confluence MP (see FIGS. 3 and 4). The ECU 10 increases the portion of the route candidate RC in which the sampling point SP is set at the interval d ₁ as the route candidate RC is closer to the confluence MP. Further, the ECU 10 increases the portion of the route candidate RC in which the sampling point SP is set at the interval d ₁ as the moving speed of the vehicle 1 increases.

Next, in step S5d, the ECU 10 is spaced along the other portion of the route candidate RC (that is, a portion excluding both a portion near the merging portion MP and a portion near the vehicle 1). Set the sampling point SP at ₂ .

On the other hand, when it is determined in step S5b that the route candidate RC is not in the vicinity of the merging portion MP (S5b: NO), the ECU 10 proceeds to step S5d without going through step S5c.

When the route candidate RC is not in the vicinity of the confluence MP (S5b: NO), the ECU 10 in step S5d along the other portion of the route candidate RC (that is, the portion excluding the portion in the vicinity of the vehicle 1). The sampling point SP is set at the interval d ₂ . At this time, the range in which the sampling point SP is set at the interval d ₂ is larger than that in the case where the route candidate RC is in the vicinity of the confluence MP (S5b: YES). That is, when the route candidate RC is not in the vicinity of the confluence MP, the number of sampling points SP set is smaller than in the case where the route candidate RC is in the vicinity of the confluence MP.

Next, in step S5e, the ECU 10 calculates the path cost at each sampling point SP of the route candidate RC. The route cost includes costs related to speed, acceleration, lateral acceleration, path change rate, obstacles, and the like. These costs can be set as appropriate. In general, route costs include travel costs and safety costs. For example, when traveling on a straight route, the travel cost is low because the travel distance is short, but when traveling on a route that avoids obstacles and the like, the travel distance is long and the travel cost is high. In addition, the movement cost increases as the lateral acceleration increases. As described above, the ECU 10 stores the value obtained by division in a memory (not shown) as the route cost of the route candidate RC.

The ECU 10 executes such an operation in step S5 for all of the plurality of route candidate RCs set in step S4.

Next, in step S6, the ECU 10 sets a target path. Specifically, the ECU 10 selects the route candidate RC having the minimum route cost, and sets the route candidate RC as the target route.

Next, in step S7, the ECU 10 transmits a control signal to the engine control system 31, the brake control system 32, and the steering control system 33 so that the vehicle 1 travels along the target route. The control signal is generated based on the control amount of the speed control and steering control of the vehicle 1 set at each sampling point SP of the target route.

Hereinafter, the operation of the vehicle driving support system 100 of the present embodiment will be described.

In the vicinity of the confluence MP where a plurality of lanes merge with each other, the traveling directions of vehicles traveling in the respective lanes intersect with each other, increasing the possibility of vehicles colliding with each other. The vehicle driving support system 100 needs to pay more attention to safety when the vehicle 1 is driven in the vicinity of such a confluence MP.

According to the above configuration, the ECU 10 which is a control device sets the sampling point SP at the interval d ₁ along the portion of the route candidate RC in the vicinity of the merging portion MP. Since the interval d ₁ is smaller than the interval d ₂ , a plurality of sampling points SP are set at a relatively high density in the vicinity of the confluence MP. As a result, the evaluation accuracy of the route cost in the vicinity of the confluence MP is made high, and the vehicle 1 can be safely driven in the vicinity of the confluence MP.

On the other hand, with respect to the other portion of the route candidate RC (that is, the portion excluding the portion near the confluence portion MP), the ECU 10 sets the sampling point SP at the interval d ₂ along the other portion. Since the interval d ₂ is larger than the interval d ₁ , a plurality of sampling points SP are set in the other portion at a relatively low density. As a result, it becomes possible to reduce the calculation load of the route cost in the other part. Since the density of the sampling point SP is relatively low, the evaluation accuracy of the route cost in the other portion is also low, but the influence of the evaluation accuracy on the running of the vehicle 1 in the vicinity of the confluence MP is relatively small.

That is, according to the above configuration, it is possible to make the evaluation accuracy of the route cost practically sufficient while reducing the calculation load. As a result, it is possible to achieve both the evaluation accuracy of the route cost of the route candidate and the reduction of the calculation load thereof.

Further, when controlling the braking system or steering system of the vehicle 1 at each sampling point SP, the vehicle 1 is set to the confluence MP by setting a plurality of sampling points SP at a relatively high density in the vicinity of the confluence MP. It is possible to drive smoothly in the vicinity and reduce the discomfort given to the driver.

Further, the ECU 10 sets a detour route candidate which is a route candidate RC for bypassing the confluence MP, and sets a sampling point SP at an interval d ₁ along a portion of the detour route candidates near the confluence MP. However, it is configured to set the sampling point SP at intervals d ₂ along the other parts.
According to this configuration, by setting the detour route candidate, the vehicle 1 can be driven so as to bypass the merging portion MP in order to ensure safety. Further, by setting the sampling point SP at the interval d ₁ and the interval d ₂ for the detour route candidate, it is possible to achieve both the evaluation accuracy of the route cost and the reduction of the calculation load for the detour route candidate. ..

Further, the ECU 10 is configured so that the closer the route candidate RC is to the confluence MP, the larger the portion of the route candidate RC where the sampling point SP is set at the interval d ₁ .
According to this configuration, the sampling point SP is preferentially set in the route candidate RC close to the confluence MP, and it is possible to achieve both the evaluation accuracy of the route cost and the reduction of the calculation load thereof.

Further, the ECU 10 is configured so that as the moving speed of the vehicle 1 increases, the portion of the route candidate RC for which the sampling point SP is set at the interval d ₁ becomes larger.
The higher the moving speed of the vehicle 1, the more attention must be paid to safety when the vehicle 1 is driven in the vicinity of the confluence MP. According to the above configuration, as the moving speed of the vehicle 1 increases, the ECU 10 increases the portion of the route candidate RC in which the sampling point SP is set at the interval d ₁ . As a result, the evaluation accuracy of the route cost in the vicinity of the confluence MP is made high, and the vehicle 1 can be safely driven in the vicinity of the confluence MP.

The embodiments of the present invention have been described above with reference to specific examples. However, the present invention is not limited to these specific examples. That is, those skilled in the art with appropriate design changes to these specific examples are also included in the scope of the present invention as long as they have the features of the present invention.

1 Vehicle 10 ECU (control unit)
21 Camera (Runway information acquisition device)
22 Radar (runway information acquisition device)
30 Navigation system (roadway information acquisition device)
100 Vehicle driving support system RC route candidate RC ₂ , RC ₃ , RC ₅ , RC ₆ Detour route candidate SP sampling point

Claims (4)

It is a vehicle driving support system installed in a vehicle.
A track information acquisition device that acquires track information related to the track,
A control device for setting a target route on the travel path based on the travel path information and controlling the vehicle so as to travel along the target route is provided.
The control device
Based on the travel route information, a plurality of route candidates are set on the travel route, and
A plurality of sampling points are set at predetermined intervals along each of the plurality of route candidates.
The path cost at each of the plurality of sampling points is calculated.
It is configured to select one route candidate from the plurality of route candidates as the target route based on the route cost.
Further, the control device sets the sampling points at the first interval along the portion of the route candidates in the vicinity of the confluence where the plurality of lanes merge with each other, and the first interval along the other portions. The sampling points are configured to be set at a second interval greater than
A vehicle driving support system characterized by this. The control device sets a detour route candidate which is the route candidate for bypassing the confluence portion, and among the detour route candidates, the sampling points at the first interval along the portion near the confluence portion. The vehicle driving support system according to claim 1, wherein the sampling point is set at the second interval along the other portion. The control device according to claim 1 or 2, wherein the route candidate closer to the confluence portion has a larger portion of the route candidate for which the sampling point is set at the first interval. Vehicle driving support system. Any one of claims 1 to 3, wherein the control device is configured so that the portion of the route candidate for which the sampling point is set at the first interval increases as the moving speed of the vehicle increases. The vehicle driving support system described in the section.

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