JP2021160660A - Vehicle control device - Google Patents

Abstract

To provide a vehicle control device that can suppress a vehicle from being unnecessarily accelerated in order to catch up with a preceding vehicle.SOLUTION: A vehicle control device 100 is configured to control a speed of a vehicle 1 so that the vehicle 1 is allowed to travel at a set target speed, which is configured to make the vehicle 1 travel at a speed equal to or lower than a predetermined set vehicle speed Vs set to the target speed so that inter-vehicle time THW for a preceding vehicle 3 is not shorter than predetermined set time Ts, when the preceding vehicle 3 is travelling ahead of the vehicle 1. Further, the device is configured to set a second set vehicle speed Vs2 higher than a speed Vp of the preceding vehicle 3 and lower than the set vehicle speed Vs to the target speed, in accordance with the inter-vehicle time THW and a relative speed Vrel of the vehicle 1 to the preceding vehicle 3, when the speed Vp of the preceding vehicle 3 is lower than the set vehicle speed Vs and the inter-vehicle time THW is longer than the set time Ts.SELECTED DRAWING: Figure 10B

Description

The present invention relates to a vehicle control device, and more particularly to a vehicle control device that assists a driver in driving a vehicle.

Conventionally, a vehicle control device that controls the speed of a vehicle is known as a driving support control of the vehicle (see, for example, Patent Document 1). Generally, in such driving support control, the vehicle is controlled to travel at a predetermined set vehicle speed set to a target speed. Then, when catching up with the preceding vehicle while traveling at the target speed (set vehicle speed), the target speed is changed from the set vehicle speed to the speed of the preceding vehicle, and the vehicle speed is controlled at the new target speed (speed of the preceding vehicle). Be told. Further, in such driving support control, the acceleration and deceleration of the vehicle are set according to the inter-vehicle distance and the relative speed between the vehicle and the preceding vehicle, so that the vehicle and the preceding vehicle suddenly approach each other. However, the predetermined inter-vehicle distance or inter-vehicle time is maintained.

Further, in the vehicle control device described in Patent Document 1, in such speed control, when the vehicle speed is smaller than the set vehicle speed, the inter-vehicle distance between the vehicle and the preceding vehicle is equal to or more than a predetermined set distance. During the period, the acceleration of the vehicle is set to a predetermined fixed acceleration, and when the inter-vehicle distance becomes equal to or less than the set distance, the acceleration of the vehicle is set to be smaller than the fixed acceleration. As described above, in the vehicle control device described in Patent Document 1, the acceleration of the vehicle is controlled when the vehicle approaches the preceding vehicle.

JP-A-2019-59360

However, in the conventional speed control, when the inter-vehicle distance between the vehicle and the preceding vehicle is equal to or greater than the set distance, the vehicle is accelerated to the set vehicle speed (target speed), and when the vehicle catches up with the preceding vehicle (for example, the inter-vehicle distance). When the set distance is reached), the vehicle is decelerated. That is, in the conventional speed control, even if the vehicle is expected to decelerate because the preceding vehicle is in front, the vehicle is unnecessarily accelerated to the set vehicle speed, so that such unnecessary acceleration is achieved. Was giving the driver a sense of discomfort.

The present invention has been made to solve such a problem, and it is possible to suppress unnecessary acceleration when catching up with a preceding vehicle in a vehicle control device for executing speed control by driving assistance. The purpose is to provide a vehicle control device.

In order to solve the above-mentioned problems, the present invention is a vehicle control device for supporting the driving of a vehicle, and the vehicle control device controls the speed of the vehicle so as to drive the vehicle at a set target speed. When the preceding vehicle is traveling in front of the vehicle, the speed is less than or equal to the predetermined set vehicle speed set as the target speed so that the inter-vehicle time with respect to the preceding vehicle does not become smaller than the predetermined set time. In addition, when the speed of the preceding vehicle is smaller than the set vehicle speed and the inter-vehicle time is larger than the set time, the vehicle is configured to follow the preceding vehicle, depending on the inter-vehicle time and the relative speed of the vehicle with respect to the preceding vehicle. It is characterized in that the second set vehicle speed, which is larger than the speed of the preceding vehicle and smaller than the set vehicle speed, is set as the target speed.

According to the present invention configured in this way, the preceding vehicle is traveling in front of the vehicle, but when the inter-vehicle time of the vehicle with respect to the preceding vehicle is larger than the set time, the second setting is smaller than the set vehicle speed. The speed of the vehicle is controlled with the vehicle speed as the target speed. Thereby, in the present invention, unnecessary acceleration can be suppressed in the process of the vehicle catching up with the preceding vehicle.

In the present invention, preferably, as the second set vehicle speed, the first additional speed set according to the inter-vehicle time and the second additional speed set according to the relative speed are added to the speed of the preceding vehicle. Is calculated by.

According to the present invention configured as described above, an appropriate second set vehicle speed can be set by setting additional speeds for each of the inter-vehicle time and the relative speed.

In the present invention, preferably, the first additional speed is set so that it becomes smaller as the inter-vehicle time becomes smaller and becomes zero when the inter-vehicle time is equal to the set time. Further, in the present invention, preferably, the second addition velocity is set so that it becomes smaller as the relative velocity increases and becomes zero when the relative velocity is equal to zero.

According to the present invention configured in this way, the target speed in the process of the vehicle catching up with the preceding vehicle and the target speed when following the vehicle after catching up can be calculated by the same calculation method. Therefore, in the present invention, the speed change until the vehicle catches up with the preceding vehicle becomes smooth, and the speed control process is simplified.

In the present invention, preferably, the vehicle control device calculates a target traveling route over a predetermined period, calculates a corrected traveling route over a predetermined period based on the target traveling route under a predetermined constraint condition, and the vehicle makes a corrected traveling route. It is configured to calculate the control target value of the vehicle for traveling on the vehicle, and the vehicle control device uses an evaluation function for evaluating the corrected traveling route under constraint conditions when calculating the corrected traveling route. The corrected travel route is calculated so as to minimize the difference in the position and speed of the vehicle on the corrected travel route with respect to at least the position and speed of the vehicle on the target travel route, and the second set vehicle speed is the speed of the preceding vehicle. It is calculated by adding the first additional speed set according to the inter-vehicle time, the second additional speed set according to the relative speed, and the third additional speed which is a fixed value.

According to the present invention configured as described above, in the case of predicting the behavior of the vehicle over a predetermined period in the future and calculating the traveling route for speed control so as to follow the preceding vehicle, the second set vehicle speed is used. By further adding the 3 additional speeds, it is possible to prevent the vehicle from taking more time than necessary until it reaches the state of following the preceding vehicle.

According to the vehicle control device of the present invention, unnecessary acceleration when catching up with the preceding vehicle can be suppressed.

It is a block diagram of the vehicle control device by embodiment of this invention. It is a figure which shows the detail of the driver operation part of the vehicle control device by embodiment of this invention. It is a control block diagram of the vehicle control device according to the embodiment of this invention. It is explanatory drawing of the control target calculation process in the vehicle control apparatus by embodiment of this invention. It is explanatory drawing of the correction traveling path in the vehicle control device by embodiment of this invention. It is explanatory drawing of the vehicle model in the vehicle control device by embodiment of this invention. It is explanatory drawing of obstacle avoidance by correction of the target traveling path in the vehicle control device by embodiment of this invention. It is explanatory drawing which shows the relationship between the permissible upper limit value and the clearance of the passing speed between an obstacle and a vehicle at the time of avoiding an obstacle in the vehicle control device by embodiment of this invention. It is a processing flow of the driving support control in the vehicle control device according to the embodiment of this invention. It is explanatory drawing of the running state of the vehicle and the preceding vehicle by embodiment of this invention. It is explanatory drawing of the speed change of the vehicle which concerns on a comparative example. It is explanatory drawing of the speed change of the vehicle by this embodiment of this invention. It is explanatory drawing of the 1st addition speed by embodiment of this invention. It is explanatory drawing of the 2nd addition rate by embodiment of this invention. It is a processing flow of the target speed calculation processing by embodiment of this invention.

Hereinafter, the vehicle control device according to the embodiment of the present invention will be described with reference to the accompanying drawings.
First, the configuration of the vehicle control device will be described with reference to FIGS. 1 and 2. FIG. 1A is a configuration diagram of a vehicle control device, FIG. 1B is a diagram showing details of a driver operation unit, and FIG. 2 is a control block diagram of the vehicle control device.

The vehicle control device 100 of the present embodiment is configured to provide different driving support controls to the vehicle 1 (see FIG. 4 and the like) equipped with the vehicle control device 100 in a plurality of driving support modes. The driver can select a desired driving support mode from a plurality of driving support modes.

As shown in FIG. 1A, the vehicle control device 100 is mounted on the vehicle 1, and includes a vehicle control calculation unit (ECU) 10, a plurality of sensors and switches, a plurality of control systems, and a user regarding a driving support mode. A driver operation unit 35 for inputting is provided. The plurality of sensors and switches include an in-vehicle camera 21, a millimeter-wave radar 22, and a plurality of behavior sensors (vehicle speed sensor 23, acceleration sensor 24, yaw rate sensor 25, steering angle sensor 26, accelerator sensor 27, brake) for detecting vehicle behavior. The sensor 28), the positioning system 29, and the navigation system 30 are included. Further, the plurality of control systems include an engine control system 31, a brake control system 32, and a steering control system 33.

As shown in FIG. 1B, the driver operation unit 35 is provided in the vehicle interior of the vehicle 1 so that the driver can operate it, and is a mode for selecting a desired driving support mode from a plurality of driving support modes. Functions as a setting operation unit. The driver operation unit 35 includes an ISA switch 36a for setting a speed limit mode, a TJA switch 36b for setting a preceding vehicle following mode, an ACC switch 36c for setting an automatic speed control mode, and a lane. A LAS switch 36d for setting the keep control mode is provided. Further, the driver operation unit 35 sets a distance setting switch 37a for setting the inter-vehicle distance in the preceding vehicle following mode (substantially, the inter-vehicle time instead of the inter-vehicle distance), and the vehicle speed in the automatic speed control mode or the like. It is provided with a vehicle speed setting switch 37b for performing the operation.

The ECU 10 shown in FIG. 1A is composed of a computer including a processor, a memory for storing various programs, an input / output device, and the like. The ECU 10 informs the engine control system 31, the brake control system 32, and the steering control system 33 based on the driving support mode selection signal and the set vehicle speed signal received from the driver operation unit 35, and the signals received from the plurality of sensors and switches. On the other hand, each of them is configured to be able to output a request signal for appropriately operating the engine system, the braking system, and the steering system.

The in-vehicle camera 21 takes an image of the surroundings of the vehicle 1 and outputs the captured image data. The ECU 10 identifies an object (for example, a vehicle, a pedestrian, a road, a lane marking (lane boundary line, white line, yellow line), a traffic signal, a traffic sign, a stop line, an intersection, an obstacle, etc.) based on image data. do. Further, in the present embodiment, the in-vehicle camera 21 also includes an in-vehicle camera that captures an image of the driver who is driving the vehicle. The ECU 10 may acquire information on the target object from the outside via an in-vehicle communication device by means of transportation infrastructure, vehicle-to-vehicle communication, or the like.

The millimeter-wave radar 22 is a measuring device that measures the position and speed of an object (particularly, a preceding vehicle, a parked vehicle, a pedestrian, an obstacle, etc.), and transmits radio waves (transmitted waves) toward the front of the vehicle 1. Then, the transmitted wave is reflected by the object and the reflected wave generated is received. Then, the millimeter wave 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 the present embodiment, instead of the millimeter wave 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. In addition, a plurality of sensors may be used to configure a position and speed measuring device.

The vehicle speed sensor 23 detects the absolute speed of the vehicle 1.
The acceleration sensor 24 detects the acceleration of the vehicle 1 (longitudinal acceleration in the front-rear direction, lateral acceleration in the lateral direction). The acceleration includes the acceleration side (positive) and the deceleration side (negative).
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 global positioning satellite system (GNSS) and / or a gyro system, and detects the position of the vehicle 1 (current vehicle position information). Further, the positioning system 29 may include a position information acquisition means by dead reckoning or road-to-vehicle communication (using Wi-Fi or the like).

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, and the like existing around the vehicle 1 (particularly, ahead in 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 is a controller that controls the engine of the vehicle 1. When it is necessary to accelerate or decelerate the vehicle 1, the ECU 10 outputs an engine output change request signal requesting a change in the engine output to the engine control system 31.

The brake control system 32 is a controller for controlling the brake device of the vehicle 1. When it is necessary to decelerate the vehicle 1, the ECU 10 outputs a brake request signal requesting the generation of a braking force to the vehicle 1 to the brake control system 32.

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

As shown in FIG. 2, the ECU 10 is a single CPU or processor that functions as an input processing unit 10a, a peripheral target detection unit 10b, a target travel route calculation unit 10c, a driving operation determination unit 10e, and a control target calculation unit 10f. It has. In the present embodiment, a single CPU is configured to execute a plurality of the above functions, but the present invention is not limited to this, and a plurality of CPUs can be configured to execute these functions.

The input processing unit 10a is configured to process various sensor / switch groups including the in-vehicle camera 21 and input information input from the driver operation unit 35. The input processing unit 10a functions as an image analysis unit that analyzes the image of the camera 21 that captures the traveling road surface and detects the traveling lane (the lane markings on both sides of the lane) in which the vehicle 1 is traveling.

The peripheral target detection unit 10b is configured to detect peripheral targets based on input information from the millimeter wave radar 22, the camera 21, and the like.
The target travel route calculation unit 10c is configured to calculate the target travel route of the vehicle based on the input information from the millimeter wave radar 22, the in-vehicle camera 21, the sensor group, and the like.

When the occupant operates the accelerator pedal, the brake pedal, or the steering wheel while the automatic speed control and / or the automatic steering control is being executed as the driving support control, the driving operation determination unit 10e gives priority to the operation by the occupant. Therefore, it is configured to output a request signal according to the operation by the occupant to the control systems 31 to 33. That is, the driving operation determination unit 10e allows the occupant to override the automatic driving support control and perform the driving operation by himself / herself.

The control target calculation unit 10f corrects the target travel route calculated by the target travel route calculation unit 10c, calculates the corrected travel route, and outputs a request signal to the control systems 31 to 33 based on the corrected travel route. It is configured as follows.

For example, when the peripheral target detection unit 10b detects a peripheral target to be avoided, the control target calculation unit 10f corrects the target travel route and calculates the corrected travel route. Further, the control target calculation unit 10f corrects the new target travel route and calculates the corrected travel route even when the target travel route itself is changed due to the change of the driving support mode. The vehicle 1 joins the new target travel route by traveling on this corrected travel route. That is, the corrected travel path in this case is a transitional route for adapting the current vehicle behavior (steering angle, acceleration, etc.) to the vehicle behavior in the new target travel route.

The control target calculation unit 10f uses a predetermined evaluation function to calculate the corrected travel route. The control target calculation unit 10f evaluates a plurality of candidate travel routes using an evaluation function with reference to the target travel route, and one corrected travel optimized to satisfy a predetermined constraint condition (or constraint condition). Calculate the route. Further, in the present embodiment, the evaluation function and the constraint condition are appropriately set based on the selected driving support mode, peripheral target, and the like.

The ECU 10 generates a request signal for at least one or a plurality of the engine control system 31, the brake control system 32, or the steering control system 33 in order to travel on the optimum correction travel path determined by the control target calculation unit 10f. And output.

Next, the driving support mode included in the vehicle control device 100 according to the present embodiment will be described. In the present embodiment, five modes (lane keep control mode, preceding vehicle following mode, automatic speed control mode, speed limit mode, and basic control mode) are provided as driving support modes.

<Lane keep control mode>
The lane keep control mode is a mode in which the vehicle 1 is steered so as to travel near the center of the lane, and is accompanied by automatic steering control and speed control (engine control, brake control) by the vehicle control device 100.

In the present embodiment, when the lane keep control mode is selected (that is, the state in which the LAS switch 36d is operated or pressed), different control is performed depending on whether or not both ends of the lane of the traveling lane can be detected. That is, during the detection of both ends of the lane, the ECU 10 performs steering control and speed control so that the vehicle 1 travels near the center of the traveling lane. However, if both ends of the lane are not detected, the driving support mode is switched to the basic control mode (off mode). In the basic control mode, the driver performs steering operation, accelerator operation, and brake operation.

Both ends of the lane are both ends of the lane in which the vehicle 1 travels (partition lines such as white lines, road edges, curbs, medians, guardrails, etc.), and are boundaries with adjacent lanes, sidewalks, and the like. .. The ECU 10 detects both ends of the lane from the image data captured by the vehicle-mounted camera 21. Further, both ends of the lane may be detected from the map information of the navigation system 30.

<Preceding vehicle following mode>
The preceding vehicle following mode is basically a mode in which the traveling locus of the preceding vehicle is followed by the vehicle 1 while maintaining a predetermined inter-vehicle distance or inter-vehicle time according to the vehicle speed between the vehicle 1 and the preceding vehicle. , With automatic steering control and speed control (engine control, brake control) by the vehicle control device 100.

In the present embodiment, the ECU 10 detects the preceding vehicle based on the image data obtained by the in-vehicle camera 21 and the measurement data obtained by the millimeter wave radar 22. Specifically, another vehicle traveling in front is detected as a traveling vehicle based on the image data obtained by the in-vehicle camera 21. Further, in the present embodiment, when the distance between the vehicle 1 and the other vehicle is less than or equal to a predetermined distance (for example, 400 to 500 m) based on the measurement data by the millimeter wave radar 22, the other vehicle is detected as a preceding vehicle. NS. Alternatively, the vehicle-mounted camera 21 and / or the millimeter-wave radar 22 may detect the preceding vehicle and output the preceding vehicle information such as the position of the preceding vehicle to the ECU 10.

In the present embodiment, when the preceding vehicle following mode is selected (that is, the state in which the TJA switch 36b is operated or pressed), different control is performed depending on whether or not the preceding vehicle can be detected. That is, during the detection of the preceding vehicle, the ECU 10 performs steering control and speed control so that the vehicle 1 follows the preceding vehicle. However, while the preceding vehicle is not detected, the ECU 10 controls the speed so that the vehicle 1 travels with the set vehicle speed (constant speed) as the target speed, and the driver performs the steering operation. The set vehicle speed can be set by, for example, the vehicle speed setting switch 37b. Alternatively, the driving support mode is switched to the basic control mode (off mode) while the preceding vehicle is not detected.

Further, in the alternative preceding vehicle following mode, different controls may be performed depending on whether or not both ends of the lane and the preceding vehicle can be detected. For example, in the alternative preceding vehicle following mode, when both ends of the lane and the preceding vehicle are detected, the ECU 10 does not allow the vehicle 1 to follow the traveling locus of the preceding vehicle, but rather a predetermined inter-vehicle distance from the preceding vehicle. Steering control and speed control are performed so that the vehicle 1 travels near the center of the traveling lane while maintaining the above. On the other hand, when the preceding vehicle is detected but both ends of the lane are not detected, the ECU 10 performs steering control and speed control so that the vehicle 1 follows the traveling locus of the preceding vehicle. Further, when both ends of the lane are detected but the preceding vehicle is not detected, the ECU 10 performs steering control and speed control so that the vehicle 1 travels near the center of the traveling lane at a set vehicle speed. Further, when neither the preceding vehicle nor both ends of the lane is detected, the ECU 10 controls the speed so that the vehicle 1 travels at the set vehicle speed, and the driver performs the steering operation.

<Automatic speed control mode>
Further, the automatic speed control mode is a mode in which the vehicle speed setting switch 37b is used to control the speed so as to maintain a predetermined set vehicle speed (constant speed) preset by the driver as the target speed, and the vehicle control device 100 It is accompanied by automatic speed control (engine control, brake control), but steering control is not performed. In this automatic speed control mode, the vehicle 1 travels so as to maintain the set vehicle speed, but the speed may be increased beyond the set vehicle speed by depressing the accelerator pedal by the driver. Further, when the driver operates the brake, the driver's intention is prioritized and the vehicle is decelerated from the set vehicle speed. In addition, when catching up with the preceding vehicle, the speed is controlled so as to follow the preceding vehicle while maintaining the inter-vehicle distance or inter-vehicle time according to the vehicle speed, and when the preceding vehicle disappears, the speed is restored to the set vehicle speed again. The speed is controlled.

<Speed limit mode>
Further, the speed limit mode is a mode in which the vehicle speed of the vehicle 1 is controlled so as not to exceed the speed limit by the speed sign or the set vehicle speed set by the driver, and the vehicle control device 100 automatically controls the speed (engine). Control) is involved, but steering control is not performed. The speed limit may be specified by the ECU 10 performing image recognition processing on the speed sign or the image data of the speed display on the road surface captured by the vehicle-mounted camera 21, or may be received by wireless communication from the outside. In the speed limit mode, even if the driver depresses the accelerator pedal so as to exceed the speed limit, the vehicle 1 is only accelerated to the speed limit.

<Basic control mode>
The basic control mode is a mode (off mode) when none of the driving support modes is selected by the driver operation unit 35, and the vehicle control device 100 does not automatically perform steering control and speed control.

Next, the target traveling route calculated by the vehicle control device 100 according to the present embodiment will be described. In the present embodiment, the target travel route calculation unit 10c provided in the ECU 10 is configured to repeatedly calculate the following first travel route R1 to third travel route R3 in time (for example, 0.1). Every second). In the present embodiment, the ECU 10 calculates a traveling route from the present time until a predetermined period (for example, 3 seconds) elapses based on the information of the sensor or the like. The travel route Rx (x = 1, 2, 3) is specified by the target position (Px_k) and target speed (Vx_k) of the vehicle 1 on the travel route set every predetermined time (for example, every 0.3 seconds). (K = 0, 1, 2, ..., N). Further, at each target position, target values are specified for a plurality of variables (acceleration, jerk, yaw rate, steering angle, vehicle angle, etc.) in addition to the target speed.

It should be noted that the first travel route to the third travel route do not consider the detection information of the peripheral targets related to the targets (obstacles such as parked vehicles and pedestrians) on or around the travel path on which the vehicle 1 travels. , The shape of the traveling path, the traveling locus of the preceding vehicle, the traveling behavior of the vehicle 1, and the set vehicle speed. As described above, in the present embodiment, since the information of the peripheral target is not taken into consideration in the calculation, the overall calculation load of these a plurality of traveling routes can be suppressed to a low level.

(1st travel route)
The first traveling route R1 is set for a predetermined period so that the vehicle 1 maintains traveling in the traveling lane according to the road shape. Specifically, the first traveling route R1 is set so as to maintain traveling near the center of the lane in principle.

The target travel route calculation unit 10c executes image recognition processing of image data around the vehicle 1 captured by the vehicle-mounted camera 21 and detects both ends of the lane. Both ends of the lane are lane markings (white lines, etc.), shoulders, etc., as described above. The target travel route calculation unit 10c sets a plurality of target positions P1_k of the first travel route R1 so that the central portion in the width direction (for example, the position of the center of gravity) of the vehicle 1 passes through the central portion in the width direction of both ends of the lane. do. Further, the target speed V1_k at each target position P1_k of the first traveling path R1 is, in principle, a speed set by the driver by the vehicle speed setting switch 37b of the driver operation unit 35, or preset by the vehicle control device 100. It is set to a predetermined set vehicle speed (constant speed).

(Second travel route)
The second travel path R2 is set for a predetermined period so as to follow the travel trajectory of the preceding vehicle. The target traveling route calculation unit 10c acquires the preceding vehicle information (position, speed, acceleration, etc. of the preceding vehicle) based on the image data by the in-vehicle camera 21, the measurement data by the millimeter wave radar 22, and the vehicle speed of the vehicle 1 by the vehicle speed sensor 23. Then, based on the preceding vehicle information, the running behavior of the preceding vehicle over a predetermined period in the future is estimated or predicted. Specifically, the target travel route calculation unit 10c assumes that the preceding vehicle travels from the present to a predetermined period after the current traveling behavior while maintaining the current traveling behavior as the predicted traveling behavior of the preceding vehicle.

Then, the target travel route calculation unit 10c is based on the predicted travel behavior of the preceding vehicle, and the vehicle 1 is at a position behind the preceding vehicle with respect to the preceding vehicle, and the inter-vehicle distance according to the speed of the vehicle 1 (actually, the preceding vehicle). The second travel path R2 (target position P2_k, target speed V2_k) is calculated so as to maintain the inter-vehicle time with and from the vehicle.

(Third travel route)
The third travel path R3 is set for a predetermined period based on the current driving state of the vehicle 1 by the driver. That is, the third traveling path R3 is set based on the position and speed estimated from the current traveling behavior of the vehicle 1 or the vehicle motion.

The target travel route calculation unit 10c calculates the third travel route R3 for a predetermined period based on the speed and yaw rate of the vehicle 1. Specifically, the third travel path R3 is calculated so that the vehicle 1 makes a steady circular turn on an arc path defined by a turning radius R (= V / φ) while maintaining the current speed V and yaw rate φ. Will be done. Therefore, the target speed V3_k of the third traveling path R3 is set to the current speed V, and the target position P3_k is set to the passing position at predetermined time intervals when the vehicle 1 travels on the arc path at the speed V. ..

Next, the relationship between the driving support mode and the traveling route in the vehicle control device 100 according to the present embodiment will be described. In the present embodiment, when the driver operates the driver operation unit 35 to select one driving support mode, one of the first to third driving routes is the target driving route according to the selected driving support mode. It is configured to be selected as.

When the lane keep control mode is selected, if both ends of the lane are detected, the first travel route is selected. In this case, the set vehicle speed set by the vehicle speed setting switch 37b becomes the target speed.
Further, when the preceding vehicle following mode is selected, the second traveling route is selected when the preceding vehicle is detected. In this case, the target speed is set according to the vehicle speed of the preceding vehicle. If the preceding vehicle is not detected when the preceding vehicle following mode is selected, the first or third traveling route is selected depending on whether or not both ends of the lane can be detected, and the set vehicle speed becomes the target speed.

Further, when the automatic speed control mode is selected, the third traveling route is selected. The automatic speed control mode is a mode in which speed control is automatically executed as described above, and the set vehicle speed set by the vehicle speed setting switch 37b is the target speed. In addition, steering control is executed based on the operation of the steering wheel by the driver.

The third travel route is also selected when the speed limit mode is selected. The speed limit mode is also a mode in which speed control is automatically executed as described above, and the target speed is set in a range equal to or less than the speed limit according to the amount of depression of the accelerator pedal by the driver. In addition, steering control is executed based on the operation of the steering wheel by the driver.

Further, when the basic control mode (off mode) is selected, the third traveling route is selected. The basic control mode is basically the same as the state in which the speed limit is not set in the speed limit mode.

Next, the control target calculation process executed by the control target calculation unit 10f of the ECU 10 according to the present embodiment will be described with reference to FIGS. 3 to 5. FIG. 3 is an explanatory diagram of the control target calculation process, FIG. 4 is an explanatory diagram of the corrected traveling route, and FIG. 5 is an explanatory diagram of the vehicle model. In the present embodiment, the control target calculation process includes a travel route correction process.

As shown in FIGS. 3 and 4, the control target calculation unit 10f corrects the target travel route R according to the change in the external environment (obstacle 3 or the like) or the driving support mode, and calculates the corrected travel route Rc. .. Then, the control target calculation unit 10f calculates a control target value (acceleration target, steering angle target) of a predetermined control amount for the vehicle 1 to travel on the corrected travel path Rc, and the vehicle 1 is based on the control target. Output the request signal to the control system. Note that FIG. 4 shows an exemplary target travel route R and corrected travel route Rc over a predetermined period (for example, 3 seconds). A target position P and a correction target position Pc are indicated for each of the paths R and Rc at predetermined time intervals (for example, every 0.3 seconds).

Specifically, the control target calculation unit 10f receives various information from the sensor / switch group, receives the target travel route R from the target travel route calculation unit 10c, and receives information on the peripheral target from the peripheral target detection unit 10b. .. Based on this information, the control target calculation unit 10f performs corrected travel optimized so that the amount of deviation from the target travel route R is small while satisfying constraint conditions (avoidance of collision with peripheral targets, etc.). Path Rc is calculated using model predictive control. That is, in the present embodiment, the control target calculation unit 10f provides a solver configured to solve the optimization problem of minimizing the evaluation value of the predetermined evaluation function J under constraints (or under constraints). include. Therefore, the control target calculation unit 10f includes an optimization calculation unit 11a and a model prediction unit 11b.

In the present embodiment, generally, the optimization calculation unit 11a avoids constraints (obstacles, etc.) based on the current behavior (speed, position, acceleration, steering angle, etc.) of the vehicle 1. A candidate correction travel path is set, and physical quantities (acceleration, rudder angle) at each candidate target position on the candidate correction travel path are given to the model prediction unit 11b as input values. By applying the input value to the vehicle model, the model prediction unit 11b calculates the behavior of the vehicle 1 on the candidate-corrected travel route, specifies each candidate target position on the candidate-corrected travel route, and determines the vehicle behavior. Various physical quantities based on the above are fed back to the optimization calculation unit 11a. Each candidate target position is calculated by accumulating the moving distances between adjacent candidate target positions.

The vehicle model defines the physical motion of the vehicle 1 and is described by the following equation of motion. This vehicle model is the two-wheel model shown in FIG. 5 in this example. The vehicle model defines the physical movement of vehicle 1.

In FIGS. 5 and (1) and (2), m is the mass of the vehicle 1, I is the yawing inertia moment of the vehicle 1, l is the wheelbase, l _f is the distance between the center of gravity of the vehicle and the front axle, and l _r is. Distance between the center of gravity of the vehicle and the rear axle, K _f is the tire cornering power per front wheel, _Kr is the tire cornering power per rear wheel, V is the vehicle speed of vehicle 1, δ is the actual steering angle of the front wheels, β is the lateral slip angle of the center of gravity of the vehicle, r is the yaw angle velocity of the vehicle 1, θ is the yaw angle of the vehicle 1, y is the lateral displacement of the vehicle 1 with respect to the absolute space, and t is the time.

The optimization calculation unit 11a evaluates the candidate-corrected travel route by using the evaluation function J based on the feedback representing the behavior of the vehicle 1 on the candidate-corrected travel route. In the present embodiment, the evaluation function J includes an evaluation term JE relating to the evaluation of the corrected traveling route and a constraint term JC relating to the constraint condition. The evaluation term JE has a plurality of evaluation factors. Further, the constraint term JC has a plurality of constraint factors. The control target calculation unit 10f sets the evaluation function J so as to be different depending on the driving support mode being executed, the sensor information, and the like.

The plurality of evaluation factors are a plurality of physical quantities representing the behavior of the vehicle 1 at the target position P (for example, velocity (vertical direction and horizontal direction), acceleration (vertical direction and horizontal direction), jerk (vertical direction and horizontal direction), It is set according to the yaw rate, the lateral position with respect to the center of the lane, the vehicle angle, the steering angle, the steering angular velocity, and other soft restrictions). The evaluation factors include a first evaluation factor in which the evaluation is higher as the difference between the physical quantities of the target travel route and the corrected travel route is smaller, and a second evaluation factor in which the evaluation is higher as the size of the physical quantity itself is smaller. In the present embodiment, the smaller the evaluation value, the higher the evaluation.

The first evaluation factor is an evaluation factor for minimizing the difference between the target travel route and the corrected travel route, and the physical quantity of the first evaluation factor is, for example, speed (vertical direction and horizontal direction), horizontal position, and the like. .. On the other hand, the second evaluation factor is an evaluation factor for minimizing a predetermined physical quantity, and the physical quantity of the second evaluation factor is, for example, acceleration (vertical direction and horizontal direction), jerk (vertical direction and horizontal direction), and so on. Steering angle, steering angular velocity, etc.

Further, a plurality of constraint factors are set corresponding to each of a plurality of physical quantities. The constraint factor is estimated as a penalty value according to the amount of the physical quantity exceeding the limit range (lower limit value to upper limit value) specified for the corresponding physical quantity. Therefore, the larger the excess amount, the larger the penalty value (that is, as a result, the larger the evaluation value).

For example, it is fixed in principle for multiple physical quantities including velocity (vertical and horizontal), acceleration (vertical and horizontal), jerk (vertical and horizontal), steering angle, steering angular velocity, and yaw rate. The limit range is specified. However, the limit range may be changed to a range narrower than the fixed limit range. For example, when the speed distribution region (see FIG. 6) described below is applied, the speed limit range with respect to the target 3 is changed according to the position of the vehicle 1.

The evaluation function J (= JE + JC) is described by the following equation.

Regarding the evaluation term JE, in the formula, Wk (Xk-Xrefk) ² is the evaluation factor, Xk is the physical quantity of the candidate correction travel route, Xrefk is the physical quantity of the target travel route or 0 (zero value), and Wk is the weighting coefficient of the evaluation factor ( For example, 0 ≦ Wk ≦ 1) (however, k = 1 to n). Therefore, in the evaluation term JE of the present embodiment, for the physical quantities of n evaluation factors, the physical quantity of the target travel route is changed from the physical quantity of the candidate correction travel route (in the case of the evaluation factor that minimizes the difference from the target travel route) or zero. The sum of the squares of the differences obtained by subtracting the values (in the case of the evaluation factor that minimizes the physical quantity itself) is weighted and corresponds to the total value over the travel path length for a predetermined period (for example, N = 3 seconds). The weighting coefficient Wk is set differently according to each driving support mode.

On the other hand, the constraint term JC corresponds to a value obtained by summing the total value of the evaluation values according to the excess amount from the limit range of the plurality of physical quantities over the travel path length of a predetermined period (for example, N = 3 seconds). Each evaluation value can be, for example, a value obtained by multiplying the squared excess amount by a predetermined weighting coefficient W. The limited range of the predetermined physical quantity may vary depending on the surrounding objects and the like.

In this embodiment, the evaluation function J is a Lagrange function incorporating the constraint term JC. Therefore, the optimization calculation unit 11a is configured to solve an unconstrained optimization problem, and the optimum solution can be derived with good convergence. If the evaluation function J does not include the constraint term JC, and the feedback from the model prediction unit 11b does not satisfy the constraint condition, the feedback does not contribute to the convergence of the optimization problem. In this case, the optimum solution may not be obtained within the predetermined calculation time.

Further, in the present embodiment, even if the feedback does not completely satisfy the constraint condition, the optimization calculation unit 11a evaluates the candidate correction travel route by the evaluation function J in consideration of the constraint condition. Can be done. Thereby, in the present embodiment, the convergence can be improved. For example, it is possible to reliably evaluate a candidate-corrected traveling route that slightly exceeds the constraint condition due to a noise error such as sensor information, an error in evaluating the road environment, an error caused by a model function, or the like. However, in the present embodiment, by setting the weighting coefficient of the constraint term JC to a large value, the constraint term JC can be reliably functioned as a constraint condition.

In the present embodiment, the optimization calculation unit 11a calculates the evaluation value for the candidate correction travel route using the evaluation function J based on the feedback from the model prediction unit 11b. The optimization calculation unit 11a sets a new candidate target travel route according to the evaluation value, and gives a corrected input value to the model prediction unit 11b based on the new candidate correction travel route. In the present embodiment, the evaluation value of the evaluation function J is minimized (or optimized) by repeating such feedback between the optimization calculation unit 11a and the model prediction unit 11b a plurality of times. The travel route Rc is calculated. The maximum number of times the feedback is repeated may be limited to a predetermined number of times.

Next, the obstacle avoidance process according to the present embodiment will be described with reference to FIGS. 6 to 7. FIG. 6 is an explanatory diagram of obstacle avoidance by correcting the target driving route, and FIG. 7 is an explanatory diagram showing the relationship between the allowable upper limit value of the passing speed between the obstacle and the vehicle and the clearance when avoiding the obstacle. be. In FIG. 6, the vehicle 1 is traveling on the traveling lane (lane) 7, and is trying to overtake the vehicle 3 by passing the vehicle 3 which is running or stopped.

Generally, when passing (or overtaking) an obstacle on or near an obstacle (for example, a preceding vehicle, a parked vehicle, a pedestrian, etc.), the driver of the vehicle 1 is in a lateral direction orthogonal to the traveling direction. A predetermined clearance or distance (lateral distance) is maintained between the vehicle 1 and the obstacle, and the speed is reduced to a speed that the driver of the vehicle 1 feels safe. Specifically, in order to avoid the danger of the preceding vehicle suddenly changing course, pedestrians coming out of the blind spot of the obstacle, or the door of the parked vehicle opening, the smaller the clearance, the more the obstacle is dealt with. The relative velocity is reduced.

Further, in general, when approaching the preceding vehicle from behind, the driver of the vehicle 1 adjusts the speed (relative speed) according to the inter-vehicle distance (longitudinal distance) along the traveling direction. Specifically, when the inter-vehicle distance is large, the approach speed (relative speed) is maintained high, but when the inter-vehicle distance is small, the approach speed is reduced. Then, the relative speed between the two vehicles becomes zero at a predetermined inter-vehicle distance. This is the same even if the preceding vehicle is a parked vehicle.

In this way, the driver drives the vehicle 1 without danger while considering the relationship between the distance between the obstacle and the vehicle 1 (including the lateral distance and the vertical distance) and the relative speed. ing.

Therefore, in the present embodiment, as shown in FIG. 6, the vehicle 1 relatives to the obstacle detected from the vehicle 1 (for example, the parked vehicle 3) around the obstacle (lateral region, rear region, And at least between the obstacle and the vehicle 1) or at least a two-dimensional distribution (velocity distribution region 40) that defines an allowable upper limit value for the relative speed in the traveling direction of the vehicle 1 is configured. There is. In the velocity distribution region 40, the permissible upper limit value V _lim of the relative velocity is set at each point around the obstacle.

As can be seen from FIG. 6, in principle, in the velocity distribution region 40, the smaller the lateral distance and the longitudinal distance from the obstacle (the closer to the obstacle), the smaller the allowable upper limit value of the relative velocity. Set. Further, in FIG. 6, for ease of understanding, an isobaric velocity line connecting points having the same allowable upper limit value is shown. The equal relative velocity lines a, b, c, and d correspond to the permissible upper limit values V _lim of 0 km / h, 20 km / h, 40 km / h, and 60 km / h, respectively. In this example, each equal relative velocity region is set to a substantially rectangular shape.

In the present embodiment, in all the driving support modes, the target traveling route is corrected so that _{the relative speed of the vehicle 1 with respect to the obstacle does not exceed the allowable upper limit value V lim in the speed distribution region 40.} That is, the speed distribution region 40 is a constraint condition for the speed of the vehicle 1. Specifically, when the control target calculation unit 10f detects an obstacle (peripheral target) to be avoided by the peripheral target detection unit 10b, the control target calculation unit 10f sets the velocity distribution region 40 for the obstacle. Then, the control target calculation unit 10f corrects the target travel route R calculated by the target travel route calculation unit 10c so as not to exceed the _{allowable upper limit value V lim defined by the speed distribution region 40.} The travel route Rc is calculated. FIG. 6 shows exemplary corrected travel paths Rc1, Rc2, Rc3.

The speed distribution region 40 does not necessarily have to be set over the entire circumference of the obstacle, and is at least behind the obstacle and on one side of the obstacle in the lateral direction in which the vehicle 1 is present (vehicle 3 in FIG. 6). It may be set in the area on the right side of.

As shown in FIG. 7, when the vehicle 1 travels at a certain absolute speed, the allowable upper limit value V _lim set in the lateral direction of the obstacle is 0 (zero) until the clearance X is D _{0 (safe distance).} It is km / h and increases in a quadratic function above _{D 0 (V lim} = k (X−D ₀ ) ^2. However, X ≧ D ₀ ). That is, in order to ensure safety, the relative speed of the vehicle 1 becomes zero _{when the clearance X is D 0 or less.} On the other hand, when the clearance X is D ₀ or more, the larger the clearance, the larger the relative speed of the vehicle 1 is allowed to pass.

In the example of FIG. 7, the allowable upper limit value in the lateral direction of the obstacle is _defined by V lim = f (X) = k (X-D ₀ ) ² . Note that k is _{a gain coefficient related to the degree of change in V lim} with respect to X, and is set depending on the type of obstacle and the like. Also, D ₀ is set depending on the type of obstacle and the like.

In the present embodiment, V _lim is defined to be a quadratic function of X, but the present invention is not limited to this, and other functions (for example, a linear function) may be defined. _{Further, although the allowable upper limit value V lim in} the horizontal direction of the obstacle has been described with reference to FIG. 7, it can be set in the same manner in all the radial directions including the vertical direction of the obstacle. At that time, the coefficient k and the safety distance D ₀ can be set according to the direction from the obstacle.

The velocity distribution region 40 can be set based on various parameters. As parameters, for example, the relative speed between the vehicle 1 and the obstacle, the type of the obstacle, the traveling direction of the vehicle 1, the moving direction and the moving speed of the obstacle, the length of the obstacle, the absolute speed of the vehicle 1, etc. should be considered. Can be done. That is, the coefficient k and the safety distance D ₀ can be selected based on these parameters.

Further, in the present embodiment, the obstacles include vehicles, pedestrians, bicycles, cliffs, ditches, holes, falling objects and the like. In addition, vehicles can be distinguished by automobiles, trucks and motorcycles. Pedestrians can be distinguished by adults, children and groups.

As shown in FIG. 6, when the vehicle 1 is traveling on the traveling path 7, the peripheral target detection unit 10b built in the ECU 10 of the vehicle 1 is an obstacle (vehicle) based on the image data from the in-vehicle camera 21. 3) is detected. At this time, the type of obstacle (in this case, vehicle, pedestrian) is specified.

Further, the peripheral target detection unit 10b calculates the position, relative speed, and absolute speed of the obstacle (vehicle 3) with respect to the vehicle 1 based on the measurement data of the millimeter wave radar 22 and the vehicle speed data of the vehicle speed sensor 23. The position of the obstacle includes an x-direction position (longitudinal distance) along the traveling direction of the vehicle 1 and a y-direction position (horizontal distance) along the lateral direction orthogonal to the traveling direction.

The control target calculation unit 10f sets a velocity distribution region 40 for each of the detected obstacles (vehicle 3 in the case of FIG. 6). Then, the control target calculation unit 10f corrects the target travel path R so that _{the speed of the vehicle 1 does not exceed the allowable upper limit value V lim of the speed distribution region 40.}

That is, when the vehicle 1 travels on the target travel path R, if the target speed exceeds the permissible upper limit value defined by the speed distribution region 40 at a certain target position, the target speed is lowered without changing the target position. Whether to make it (path Rc1 in FIG. 6) or change the target position on the detour route so that the target speed does not exceed the allowable upper limit value without changing the target speed (path Rc3 in FIG. 6), the target position and the target. Both speeds are changed (path Rc2 in FIG. 6).

In general, in the evaluation function J, the corrected traveling path Rc1 is calculated when the weighting coefficient of the evaluation factor for minimizing the steering angular velocity is large, and the weight of the evaluation factor for minimizing the acceleration in the front-rear direction is calculated. When the coefficient is large, the corrected travel path Rc3 is calculated.

For example, FIG. 6 shows a case where the calculated target travel path R is a route traveling at a center position (target position) in the width direction of the travel path 7 at 60 km / h (target speed). In this case, the parked vehicle 3 exists in front as an obstacle, but as described above, this obstacle is not considered in the calculation stage of the target traveling route R in order to reduce the calculation load.

When traveling on the target travel path R, the vehicle 1 crosses the isobaric velocity lines d, c, c, and d of the speed distribution region 40 in order. That is, the vehicle 1 traveling at 60 km / h enters the region inside the equal relative speed line d (allowable upper limit value V _{lim = 60 km / h).} Therefore, the control target calculation unit 10f corrects the target travel path R so as to limit the target speed at each target position of the target travel path R to the allowable upper limit value V _lim or less, and generates the corrected travel path Rc1. That is, in the corrected travel path Rc1, the target speed gradually decreases to less than 40 km / h as the vehicle approaches the vehicle 3 so that the target speed becomes equal to or less than the _{allowable upper limit value V lim at each target position, and then the vehicle.} The target speed is gradually increased to the original 60 km / h as the distance from 3 is increased.

Further, the corrected travel path Rc3 is set so as to travel outside the isobaric speed line d (corresponding to the relative speed of 60 km / h) without changing the target speed (60 km / h) of the target travel route R. It is a route. In order to maintain the target speed of the target travel path R, the control target calculation unit 10f corrects the target travel path R so as to change the target position so that the target position is located on or outside the equal relative speed line d. Therefore, the corrected travel path Rc3 is generated. Therefore, the target speed of the corrected travel path Rc3 is maintained at 60 km / h, which is the target speed of the target travel path R.

Further, the corrected travel route Rc2 is a route in which both the target position and the target speed of the target travel route R are changed. In the corrected travel path Rc2, the target speed is not maintained at 60 km / h, gradually decreases as it approaches the vehicle 3, and then gradually increases to the original 60 km / h as it moves away from the vehicle 3. Will be done.

A correction that does not change the target position of the target travel path R and changes only the target speed, such as the correction travel path Rc1, can be applied to a driving support mode that involves speed control but not steering control (the correction travel path Rc1). For example, automatic speed control mode, speed limit mode, basic control mode).
Further, a correction for changing only the target position without changing the target speed of the target travel path R, such as the correction travel path Rc3, can be applied to a driving support mode accompanied by steering control (for example, following a preceding vehicle). mode).
Further, a correction for changing both the target position and the target speed of the target traveling path R, such as the corrected traveling path Rc2, can be applied to a driving support mode accompanied by speed control and steering control (for example, a preceding vehicle following mode). ).

Next, the processing flow of the driving support control in the vehicle control device 100 of the present embodiment will be described with reference to FIG. FIG. 8 is a processing flow of driving support control.
The ECU 10 repeatedly executes the processing flow shown in FIG. 8 at predetermined time intervals (for example, 0.1 seconds). First, the ECU 10 (input processing unit 10a) executes the information acquisition process (S11). In the information acquisition process, the ECU 10 acquires the current vehicle position information and map information from the positioning system 29 and the navigation system 30 (S11a), and the in-vehicle camera 21, millimeter wave radar 22, vehicle speed sensor 23, acceleration sensor 24, and yaw rate sensor. 25, Sensor information is acquired from the driver operation unit 35 and the like (S11b), and switch information is acquired from the steering angle sensor 26, the accelerator sensor 27, the brake sensor 28 and the like (S11c).

Next, the ECU 10 (input processing unit 10a, peripheral target detection unit 10b) executes a predetermined information detection process using various information acquired in the information acquisition process (S11) (S12). In the information detection process, the ECU 10 uses the current vehicle position information, map information, and sensor information to provide lane information (presence / absence of straight section and curved section, length of each section, curve) regarding the shape of the lane in the surrounding and front areas of the vehicle 1. Radiation of curvature of section, lane width, position of both ends of lane, number of lanes, presence / absence of intersection, speed limit defined by curve curvature, etc.), driving regulation information (speed limit, red light, etc.), preceding vehicle information (preceding vehicle) (Position, speed, acceleration, etc.) and peripheral target information are detected (S12a).

Further, the ECU 10 detects vehicle operation information (steering angle, accelerator pedal depression amount, brake pedal depression amount, etc.) related to vehicle operation by the driver from the switch information (S12b), and further, the vehicle from the switch information and sensor information. The traveling behavior information (vehicle speed, longitudinal acceleration, lateral acceleration, yaw rate, etc.) relating to the behavior of 1 is detected (S12c).

Next, the ECU 10 (target travel route calculation unit 10c) executes the target travel route calculation process based on the information obtained by the calculation (S13). In the target driving route calculation process, as described above, the first traveling route R1, the second traveling route R2, and the third traveling route R3 are calculated, and the driving support mode and the sensor information selected from these are calculated. The target travel route R is selected according to the preceding vehicle, both ends of the lane, etc.).

The target traveling route calculation process includes a target speed calculation process (S13a) for setting a target speed. In this target speed calculation process, in principle, the set vehicle speed set by the vehicle speed setting switch 37b is set as the target speed, but as will be described later, when a preceding vehicle is detected, the speed is lower than the set vehicle speed. The second set vehicle speed may be set to the target speed.

Next, the ECU 10 (control target calculation unit 10f) executes the control target calculation process based on the target travel path R, peripheral target information, various sensor information, and the like (S14). In the control target calculation process, as described above, the corrected travel path Rc is calculated, and the control target (acceleration target, steering angle target) of a predetermined control amount at each correction target position Pc on the corrected travel path Rc is generated. NS.

Finally, the ECU 10 (control target calculation unit 10f) executes the system control process based on the generated control target in the corrected travel path Rc (S15), and ends the process. In the system control process, request signals (engine request signal, brake request signal, steering request signal) are generated according to the control target in the corrected travel path Rc, and the generated request signals are sent to the control systems 31 to 33 of the vehicle 1. It is output.

Next, with reference to FIGS. 9 to 12, the application of the transient set vehicle speed when the vehicle of the present embodiment catches up with the preceding vehicle will be described. 9 is an explanatory diagram of a running state of the vehicle and the preceding vehicle, FIG. 10A is an explanatory diagram of the speed change of the vehicle according to the comparative example, and FIG. 10B is an explanatory diagram of the speed change of the vehicle of the present embodiment. FIG. 11A is an explanatory diagram of the first additional speed, and FIG. 11B is an explanatory diagram of the second additional speed. FIG. 12 is a processing flow of the target speed calculation process.

In FIG. 9, the vehicle 1 travels at a speed V0, and the preceding vehicle travels at a speed Vp (Vp <V0) lower than that of the vehicle 1. The preceding vehicle 3 is traveling far away from the vehicle 1. That is, the inter-vehicle time THW between the preceding vehicle 3 and the vehicle 1 is larger than the set time Ts (for example, 2 seconds) set as the target value of the inter-vehicle time in the preceding vehicle following mode and the automatic speed control mode (THW>. Ts). Further, in the vehicle 1, the set vehicle speed is set to Vs by the vehicle speed setting switch 37b (Vs> V0, Vs> Vp). The inter-vehicle time THW is calculated by dividing the inter-vehicle distance between the preceding vehicle 3 and the vehicle 1 by the current speed V0 of the vehicle 1.

In the comparative example shown in FIG. 10A, when the speed is automatically controlled (for example, when the TJA switch 36b or the ACC switch 36c is selected), the target traveling route calculated when the set vehicle speed Vs is set to the target speed. The speed at each target point is shown. In this case, the vehicle 1 is accelerated toward the set vehicle speed Vs (target speed). Then, at time t1, the speed of the vehicle 1 reaches the set vehicle speed Vs. After that, when the vehicle 1 catches up with the preceding vehicle 3, it starts decelerating with a relatively large deceleration, and reaches the speed Vp of the preceding vehicle 3 at time t2. In this case, the vehicle 1 catches up with the preceding vehicle 3 at an early stage, but after catching up, the vehicle 1 eventually decelerates significantly. Therefore, in the example of FIG. 10A, the vehicle 1 is accelerated more than necessary, and it is uneconomical from the viewpoint of fuel consumption.

Therefore, in the present embodiment, as shown in FIG. 10B, when the vehicle 1 detects the preceding vehicle 3, the transient second set vehicle speed Vs2 (Vp <Vs2 <Vs) is set to the automatic speed instead of the set vehicle speed Vs. Set to the target speed in control. FIG. 10B shows the speed at each target point of the target traveling route calculated when the second set vehicle speed Vs2 is set as the target speed. In this case, the vehicle 1 is accelerated with the second set vehicle speed Vs2 as the target speed, and reaches the second set vehicle speed Vs2 at the time t3. After that, when the vehicle 1 catches up with the preceding vehicle 3, the vehicle 1 gradually starts decelerating and reaches the speed Vp of the preceding vehicle 3 at time t4. Therefore, in the present embodiment, unnecessary acceleration in the process in which the vehicle 1 catches up with the preceding vehicle 3 can be suppressed.

In the present embodiment, the second set vehicle speed Vs2 is calculated by the following formula.
Vs2 = Vp + V1 + V2 + V3
Here, V1 is the first addition speed, V2 is the second addition speed, and V3 is the third addition speed (V1 ≧ 0, V2 ≧ 0, V3 ≧ 0).

As shown in FIG. 11A, the first additional speed V1 is set according to the inter-vehicle time THW. That is, when the inter-vehicle time THW is equal to or less than a predetermined first threshold value Tth1 (Tth1> 0), V1 is zero (V1 = 0), and when the inter-vehicle time THW is equal to or greater than the first threshold value Tth1, the larger the inter-vehicle time THW. , V1 is set large (V1 = k1 · (THW-Tth1), k1> 0). The first threshold value Tth1 functions as a dead zone and is set to a value larger than the set time Ts (Tth1> Ts). For example, when Ts is 2 seconds, Tth1 is 3 seconds. Therefore, as the inter-vehicle time THW is larger, the vehicle catches up with the preceding vehicle 3 relatively early, so that the first additional speed V1 is set to a larger value. On the other hand, when the vehicle 1 catches up with the preceding vehicle 3, the first additional speed V1 becomes zero.

As shown in FIG. 11B, the second additional speed V2 is set according to the relative speed Vrel (Vrel = V0-Vp) of the vehicle 1 with respect to the preceding vehicle 3. That is, when the relative velocity Vrel is equal to or higher than the predetermined second threshold value Vth2 (Vth2 <0), V2 is zero (V2 = 0), and when the relative velocity Vrel is equal to or lower than the second threshold value Vth2, the smaller the relative velocity Vrel is. , V2 is set large (V2 = k2 · (Vth2-Vrel), k2> 0). The second threshold value Vth2 functions as a dead zone and is set to a predetermined negative value (for example, −10 km / h). Therefore, the slower the vehicle 1 is than the preceding vehicle 3, the earlier the vehicle 1 catches up with the preceding vehicle 3, so that the second additional speed V2 is set to a larger positive value. On the other hand, if the vehicle 1 and the preceding vehicle 3 have substantially the same speed or the vehicle 1 is faster than the preceding vehicle 3, the second additional speed V2 becomes zero.

The third additional speed V3 is set to a fixed value (for example, V3 = 2 km / h). In the present embodiment, as shown in FIG. 10B, the position and speed at each target point of the target traveling route R are calculated so that the target speed of the vehicle 1 gradually reaches the second set vehicle speed Vs2. At this time, if the target traveling route R is calculated with the second set vehicle speed Vs2 itself as the target speed, it takes time for the speed at the target point of the target traveling route R to reach the second set vehicle speed Vs2. Therefore, by adding the third additional speed V3, the speed at the target point of the target traveling route R is reached to the second set vehicle speed Vs2 at an early stage.

As shown in FIG. 12, the ECU 10 (target traveling route calculation unit 10c) executes the target speed calculation process (S13a) in the processing flow of FIG. First, the ECU 10 acquires the set vehicle speed Vs set by the vehicle speed setting switch 37b (S131), and determines whether or not the current speed V0 of the vehicle 1 is smaller than the set vehicle speed Vs (S132). However, when the set vehicle speed Vs exceeds the legal speed limit set on the traveling path, the legal speed limit can be used instead of the set vehicle speed Vs.

When the current speed V0 is already equal to or higher than the set vehicle speed Vs (S132; No), the ECU 10 sets the set vehicle speed Vs to the target speed. On the other hand, when the current speed V0 is smaller than the set vehicle speed Vs (S132; Yes), the ECU 10 calculates the second set vehicle speed Vs2 as described above (S133), and the second set vehicle speed Vs2 is smaller than the set vehicle speed Vs. Whether or not it is determined (S134).

When the second set vehicle speed Vs2 is equal to or higher than the set vehicle speed Vs (S134; No), the ECU 10 sets the set vehicle speed Vs to the target speed and ends the process. On the other hand, when the second set vehicle speed Vs2 is smaller than the set vehicle speed Vs (S134; Yes), the ECU 10 sets the second set vehicle speed Vs2 to the target speed and ends the process. As described above, the second set vehicle speed Vs2 is adopted as the target speed only when the calculated second set vehicle speed Vs2 is smaller than the set vehicle speed Vs.

Next, the operation of the vehicle control device 100 according to the embodiment of the present invention will be described.
The vehicle control device 100 for supporting the operation of the vehicle 1 according to the embodiment of the present invention is configured to control the speed of the vehicle 1 so as to drive the vehicle 1 at a set target speed. When the preceding vehicle 3 is traveling in front of the vehicle (see FIG. 9), the inter-vehicle time THW with respect to the preceding vehicle 3 is equal to or less than the predetermined set vehicle speed Vs set at the target speed so as not to be smaller than the predetermined set time Ts. When the vehicle 1 is configured to follow the preceding vehicle 3 at a speed, the speed Vp of the preceding vehicle 3 is smaller than the set vehicle speed Vs, and the inter-vehicle time THW is larger than the set time Ts, the inter-vehicle time THW (FIG. 11A). The second set vehicle speed Vs2, which is larger than the speed Vp of the preceding vehicle 3 and smaller than the set vehicle speed Vs, is set as the target speed according to the relative speed Vrel of the vehicle 1 with respect to the preceding vehicle 3 (see FIG. 11B). It is configured as follows.

In the present embodiment configured as described above, the preceding vehicle 3 is traveling in front of the vehicle 1, but when the inter-vehicle time THW of the vehicle 1 with respect to the preceding vehicle 3 is larger than the set time Ts, the speed is higher than the set vehicle speed Vs. The speed of the vehicle 1 is controlled with the second set vehicle speed Vs2, which is also small, as the target speed. Thereby, in the present embodiment, unnecessary acceleration can be suppressed in the process in which the vehicle 1 catches up with the preceding vehicle 3.

Further, in the present embodiment, the second set vehicle speed Vs2 is set according to the speed Vp of the preceding vehicle 3, the first additional speed V1 set according to the inter-vehicle time THW, and the second set vehicle speed Vrel. It is calculated by adding the addition speed V2.

In the present embodiment configured as described above, an appropriate second set vehicle speed Vs2 can be set by setting an additional speed for each of the inter-vehicle time THW and the relative speed Vrel.

Specifically, the first additional speed V1 is set so that it becomes smaller as the inter-vehicle time THW becomes smaller, and becomes zero when the inter-vehicle time THW is equal to the set time Ts. Further, the second additional velocity V2 is set so that it becomes smaller as the relative velocity Vrel becomes larger and becomes zero when the relative velocity Vrel is equal to zero. In the present embodiment configured in this way, the target speed in the process in which the vehicle 1 catches up with the preceding vehicle 3 and the target speed in the follow-up running after catching up can be calculated by the same calculation method. Therefore, in the present embodiment, the speed change until the vehicle 1 catches up with the preceding vehicle 3 becomes smooth, and the speed control process is simplified.

Further, in the present embodiment, the vehicle control device 100 calculates the target travel route R over a predetermined period, calculates the corrected travel route Rc over a predetermined period based on the target travel route R under a predetermined constraint condition, and calculates the corrected travel route Rc over a predetermined period. 1 is configured to calculate the control target value of the vehicle 1 for traveling on the corrected traveling route Rc, and the vehicle control device 100 calculates the corrected traveling route Rc under the constraint condition. Using the evaluation function J for evaluating the route Rc, at least the corrected travel with respect to the position and speed of the vehicle 1 on the target travel route R so as to minimize the difference in the position and speed of the vehicle 1 on the travel route Rc. The route Rc is calculated, and the second set vehicle speed Vs2 is the first additional speed V1 set according to the inter-vehicle time THW and the second additional speed V2 set according to the relative speed Vrel in the speed Vp of the preceding vehicle 3. , And the third addition velocity V3, which is a fixed value, is added.

In the present embodiment configured in this way, in the case of predicting the behavior of the vehicle 1 over a predetermined period in the future and calculating the traveling route for speed control so as to follow the preceding vehicle 3, the second set vehicle speed Vs2 By further adding the third additional speed V3 to the vehicle 1, it is possible to prevent the vehicle 1 from taking more time than necessary until it reaches the state of following the preceding vehicle 3.

1 vehicle 3 preceding vehicle 10 ECU
100 Vehicle control device R Target travel route Rc Corrected travel route Ts Set time Tth1 First threshold V1 First additional speed V2 Second additional speed V3 Third additional speed Vp Preceding vehicle speed Vrel Relative speed Vs Set vehicle speed Vs2 Second set vehicle speed Vth2 2nd threshold

Claims (5)

It is a vehicle control device to support the driving of the vehicle.
The vehicle control device is configured to control the speed of the vehicle so as to drive the vehicle at a set target speed.
When the preceding vehicle is traveling in front of the vehicle, the vehicle is moved at a speed equal to or lower than the predetermined set vehicle speed set at the target speed so that the inter-vehicle time with respect to the preceding vehicle does not become smaller than the predetermined set time. It is configured to follow the preceding vehicle,
Further, when the speed of the preceding vehicle is smaller than the set vehicle speed and the inter-vehicle time is larger than the set time, the speed of the preceding vehicle is higher than the speed of the preceding vehicle according to the inter-vehicle time and the relative speed of the vehicle with respect to the preceding vehicle. A vehicle control device configured to set a second set vehicle speed, which is large and smaller than the set vehicle speed, as the target speed. The second set vehicle speed is calculated by adding a first additional speed set according to the inter-vehicle time and a second additional speed set according to the relative speed to the speed of the preceding vehicle. The vehicle control device according to claim 1. The vehicle control device according to claim 2, wherein the first additional speed becomes smaller as the inter-vehicle time becomes smaller, and becomes zero when the inter-vehicle time is equal to the set time. The vehicle control device according to claim 2 or 3, wherein the second addition speed decreases as the relative speed increases, and is set to be zero when the relative speed is equal to zero. The vehicle control device is
Calculate the target travel route over a predetermined period and
It is configured to calculate the corrected traveling route over the predetermined period based on the target traveling route under a predetermined constraint condition, and to calculate the control target value of the vehicle for the vehicle to travel on the corrected traveling route. And
When calculating the corrected travel route, the vehicle control device uses an evaluation function for evaluating the corrected travel route under the constraint conditions, and at least the position and speed of the vehicle on the target travel route. The corrected travel path is calculated so as to minimize the difference in the position and speed of the vehicle on the corrected travel route.
The second set vehicle speed is the speed of the preceding vehicle, the first additional speed set according to the inter-vehicle time, the second additional speed set according to the relative speed, and the third additional speed which is a fixed value. The vehicle control device according to any one of claims 1 to 4, which is calculated by adding a speed.

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