Patent Application
20200180614
The present invention relates to a vehicle control device, and more particularly to a vehicle control device suited to avoiding an obstacle during vehicle traveling.
There has been proposed a technique of, during emergency obstacle avoidance, selecting one of breaking-based avoidance (based on only brake manipulation) and steering-based avoidance (based on only steering manipulation), according to a vehicle speed at that time, and calculating a target traveling course, using optimization processing (see, for example, the following Patent Document 1). In this technique, when the breaking-based avoidance is selected, conditions for the calculation will be simplified and limited to only a longitudinal (vehicle forward-rearward directional) motion. On the other hand, when the steering-based avoidance is selected, the conditions for the calculation will be simplified and limited to only a lateral (vehicle width directional) motion. As above, the technique allows a calculation load to be reduced during an emergency, so that it is possible to shorten a calculation time period while ensuring a high calculation accuracy.
In a situation where a driver manipulates a vehicle by himself/herself to avoid an obstacle, the obstacle avoidance is performed differently according to a preference of the driver. Specifically, a certain user passes over a position close to the obstacle, while sufficiently decelerating the vehicle (braking emphasis). On the other hand, another driver passes over a position sufficiently distant from the obstacle, almost without decelerating the vehicle (speed emphasis). Yet another driver passes over a position moderately distant from the obstacle, while decelerating the vehicle to some degree (braking-speed balance emphasis). Thus, in calculation of a target traveling course during obstacle avoidance, it is desirable to allow a balance between braking and steering to be adjusted according to driver's preference and a traveling environment
The present invention has been made to solve the above problem, and an object thereof is to provide a vehicle control device capable of appropriately adjusting a target traveling course during obstacle avoidance.
In order to achieve the above object, the present invention provides a vehicle control device which comprises a target traveling course calculation part to calculate a target traveling course of a vehicle, wherein the target traveling course calculation part is configured to, upon detection of an obstacle, execute traveling course correction processing of correcting the target traveling course so as to avoid the obstacle, wherein the target traveling course calculation part is configured to, in the traveling course correction processing, correct the target traveling course to calculate a plurality of corrected traveling course candidates for avoiding the obstacle; and evaluate the corrected traveling course candidates with respect to the target traveling course by a given evaluation function J including a plurality of evaluation factors, to derive one corrected traveling course according to the evaluation, and wherein the target traveling course calculation part is configured to revise the evaluation factors based on an external signal.
In the vehicle control device of the present invention having the above feature, it is possible to correct the target traveling course to derive the corrected traveling course. Specifically, in the traveling course correction processing, one corrected traveling course is derived by evaluating the corrected traveling course candidates, using the evaluation function including the plurality of evaluation factors. Further, the target traveling course calculation part can operate to revise the evaluation factors in response to receiving an external signal. This makes it possible to revise the evaluation factor according to the situation to derive an adequate corrected traveling course.
Preferably, in the vehicle control device of the present invention, the revision of the evaluation function is to change weighting among the evaluation factors. According to this feature, it is possible to perform the revision of the evaluation function readily and effectively.
Preferably, the vehicle control device of the present invention comprises a revision part to allow a driver to revise the evaluation factors of the evaluation function, wherein the revision part is configured to, when the driver manipulates the revision part, output a revision request signal as the external signal. According to this feature, the driver can manipulate the revision part to revise the evaluation factors of the evaluation function, according to a preference of the driver.
More preferably, in the above vehicle control device, the evaluation factors include an evaluation factor regarding a longitudinal behavior of the vehicle, and an evaluation factor regarding a lateral behavior of the vehicle, wherein the revision part is configured to revise the evaluation factor regarding the longitudinal behavior of the vehicle, and the evaluation factor regarding the lateral behavior of the vehicle. According to this feature, the evaluation factor regarding the longitudinal and lateral behaviors can be revised, so that it is possible to derive the corrected traveling course with an emphasis on one or both of vehicle speed and steering, according the preference of the driver.
Preferably, in the vehicle control device of the present invention, the vehicle has a plurality of driving support modes, wherein a numerical range in which the evaluation factors are permitted to be revised is set differently according to each of the driving support modes. According to this feature, it is possible to derive the corrected traveling course within an adequate range according to each of the driving support modes.
Preferably, in the vehicle control device of the present invention, the target traveling course calculation part is configured to, in the traveling course correction processing, derive the corrected traveling course so as to satisfy a given limiting condition for limiting a behavior of the vehicle, wherein the vehicle control device is configured to prevent change of the limiting condition by a driver. According to this feature, it is possible to prevent deterioration in safety due to erroneous change of the limiting condition by the driver.
Preferably, the vehicle control device of the present invention comprises an environmental information acquisition part to acquire environmental information regarding a weather or a traveling road state around the vehicle, wherein the target traveling course calculation part is configured to receive, as the external signal, the environmental information from the environmental information acquisition part, and revise the evaluation factors according to the received environmental information. According to this feature, it is possible to automatically revise the evaluation factors in conformity to a change in environmental condition.
Preferably, in the vehicle control device of the present invention, the target traveling course calculation part is configured to, in the traveling course correction processing, derive the corrected traveling course so as to satisfy a given limiting condition for limiting a behavior of the vehicle, and the vehicle control device comprises an environmental information acquisition part to acquire environmental information regarding a weather or a traveling road state around the vehicle, wherein the target traveling course calculation part is configured to revise the limiting condition according to the environmental information acquired by the environmental information acquisition part. According to this feature, it is possible to automatically revise the limiting condition in conformity to a change in environmental condition.
Preferably, in the vehicle control device of the present invention, the target traveling course calculation part is configured to, in the traveling course correction processing, set a speed distribution area defining a distribution area of an allowable upper limit of a relative speed of the vehicle with respect to the obstacle, in a direction at least from the obstacle toward the vehicle; and correct the target traveling course to calculate the corrected traveling course candidates, such that the relative speed of the vehicle with respect to the obstacle does not exceed the allowable upper limit in the speed distribution area.
According to this feature, the vehicle control device can define the speed distribution area between the obstacle and the vehicle, and correct the target traveling course without exceeding the allowable upper limit of the relative speed defined by the speed distribution area, thereby calculating the corrected traveling course candidates. Therefore, by using the speed distribution area, it is possible to reduce a feeling of strangeness to be given to a driver by the corrected traveling course.
Preferably, in the vehicle control device of the present invention, the target traveling course calculation part is configured to, in the traveling course correction processing, drive the corrected traveling course, using a given vehicle model defining physical motions of the vehicle. According to this feature, it is possible to derive the corrected traveling course which gives a less feeling of strangeness, and early converge optimization processing based on the evaluation function.
Preferably, in the vehicle control device of the present invention, the evaluation function is expressed as a total value of differences in respective physical amounts of the evaluation factors between each of the corrected traveling course candidates and the target traveling course, wherein the target traveling course calculation part is configured to, in the traveling course correction processing, select one of the corrected traveling course candidates which is smallest in terms of the total value. According to this feature, it is possible to derive a corrected traveling course having the smallest difference from the target traveling course, to the extent that does not exceed the allowable upper limit of the relative speed defined by the speed distribution area.
Specifically, in the above vehicle control device, the evaluation factor regarding the longitudinal behavior of the vehicle may include at least a longitudinal speed of the vehicle or a longitudinal acceleration of the vehicle, and the evaluation factor regarding the lateral behavior of the vehicle may include at least one of a lateral speed of the vehicle, a lateral acceleration of the vehicle, and a yaw rate of the vehicle.
Specifically, in the above vehicle control device, the limiting condition may include at least one of speed, acceleration, acceleration change rate, steering angle, steering angular speed, and yaw rate
Preferably, the vehicle control device of the present invention further comprises a traveling behavior control part to execute traveling behavior control processing including speed control and/or steering control of the vehicle, so as to cause the vehicle to travel on the corrected traveling course. According to this feature, it is possible to, upon setting of the corrected traveling course, control the vehicle to travel on the corrected traveling course by the speed control and/or the manipulation control.
The present invention can provide a vehicle control device capable of appropriately adjusting the target traveling course during obstacle avoidance.
With reference to the accompanying drawings, a vehicle control system according to one embodiment of the present invention will now be described. First of all, the configuration of the vehicle control system will be described with reference to
The vehicle control system 100 according to this embodiment is configured to provide different driving support controls to a vehicle 1 (see
As shown in
The driver manipulation unit 35 is provided in a passenger compartment of the vehicle 1 such that it can be manipulated by the driver, and comprises: a mode selection switch 36 for selecting a desired driving support mode from the plural driving support modes; a setting vehicle speed input part 37 for inputting a setting vehicle speed in accordance with the selected driving support mode; and a revision part 38 for reflecting a preference of the driver on the after-mentioned traveling course calculation. In response to manipulation of the mode selection switch 36 by the driver, a driving support mode selection signal according to the selected driving support mode is output. On the other hand, in response to manipulation of the setting vehicle speed input part 37 by the driver, a setting vehicle speed signal is output. In response to manipulation of the revision part 38 by the driver, a revision request signal is output.
The ECU 10 is composed of a computer comprising a CPU, a memory storing therein various programs, and an input/output device. The ECU 10 is configured to be operable, based on the driving support mode selection signal, the setting vehicle speed signal, and signals received from the sensors and switches, to output request signals for appropriately operating an engine system, a brake system and a steering system, respectively, to the engine control system 31, the brake control system 32 and the steering control system 33.
The vehicle-mounted camera 21 is operable to take images around the vehicle 1 and output image data about the taken images. The ECU 10 is operable to identify an object (e.g., a vehicle, a pedestrian, a road, a demarcation line (a lane border line, a white road line or a yellow road line), a traffic light, a traffic sign, a stop line, an intersection, an obstacle or the like) based on the image data. Here, the ECU 10 may be configured to acquire information regarding such an object, from outside through an in-vehicle communication device, by means of transportation infrastructure, inter-vehicle communication, etc.
The millimeter-wave radar 22 is a measurement device for measuring the position and speed of the object (particularly, a preceding vehicle, a parked vehicle, a pedestrian, an obstacle or the like), and is operable to transmit a radio wave (transmitted wave) forwardly with respect to the vehicle 1 and receive a reflected wave produced as a result of reflection of the transmitted wave by the object. Then, the millimeter-wave radar 22 is operable, based on the transmitted wave and the received wave, to measure a distance between the vehicle 1 and the object, i.e., a vehicle-object distance, (e.g., inter-vehicle distance) and/or a relative speed of the object with respect to the vehicle 1. In this embodiment, instead of the millimeter-wave radar 22, a laser radar, an ultrasonic sensor or the like may be used to measure the vehicle-object distance and/or the relative speed. Further, the position and speed measurement device may be composed using a plurality of other sensors.
The vehicle speed sensor 23 is operable to detect an absolute speed of the vehicle 1.
The accelerator sensor 24 is operable to detect an acceleration (a longitudinal (forward-rearward directional) acceleration, and a lateral (width directional) acceleration) of the vehicle 1. Here, the acceleration includes a speed-increasing side (positive acceleration) and a speed-reducing side (negative acceleration).
The yaw rate sensor 25 is operable to detect a yaw rate of the vehicle 1.
The steering angle sensor 26 is operable to detect a turning angle (steering angle) of a steering wheel of the vehicle 1.
The accelerator sensor 27 is operable to detect a depression amount of an accelerator pedal of the vehicle 1.
The brake sensor 28 is operable to detect a depression amount of a brake pedal of the vehicle 1.
The position measurement system 29 is composed of a GPS system and/or a gyro system, and is operable to detect the position of the vehicle 1 (current vehicle position information).
The navigation system 30 stores therein map information, and is operable to provide the map information to the ECU 10. Then, the ECU 10 is operable, based on the map information and the current vehicle position information, to identify a road, an intersection, a traffic light, a building and others existing around the vehicle 1 (particularly, ahead of the vehicle 1 in the travelling direction). The map information may be stored in the ECU 10.
The environment sensor 39 is operable to acquire information about an external environment of the vehicle 1. The environment information includes weather information (an ambient temperature, an ambient humidity, a rainfall amount, etc.), and traveling road information (a road surface temperature, a road surface friction coefficient, a road surface gradient, a road surface material, etc.). The environment sensor 39 may be composed of a sensor (a temperature sensor, a humidity sensor, a rainfall amount, etc.) for directly detecting the above information, or a receiving device for acquiring the above information from an external information source in the form of a wireless information signal.
The engine control system 31 comprises a controller for controlling an engine of the vehicle 1. The ECU 10 is operable, when there is a need to accelerate or decelerate the vehicle 1, to output, to the engine control system 31, an engine output change request signal for requesting to change an engine output.
The brake control system 32 comprises a controller for controlling a braking device of the vehicle 1. The ECU 10 is operable, when there is a need to decelerate the vehicle 1, to output, to the brake control system 32, a braking request signal for requesting to generate a braking force to be applied to the vehicle 1.
The steering control system 33 comprises a controller for controlling a steering device of the vehicle 1. The ECU 10 is operable, when there is a need to change the travelling direction of the vehicle 1, to output, to the steering control system 33, a steering direction change request signal for requesting to change a steering direction.
Next, the driving support modes in the vehicle control system 100 according to this embodiment will be described. In this embodiment, the driving support modes consist of five modes (a preceding vehicle following mode, a lane-keep control mode, an automatic speed control mode, a speed limiting mode, and a basic control mode).
The preceding vehicle following mode is a mode in which the vehicle 1 is basically controlled to travel following a preceding vehicle, while maintaining a given inter-vehicle distance between the vehicle 1 and the preceding vehicle, and involves automatic steering control, automatic speed control (engine control and/or brake control), automatic obstacle avoidance control (the speed control and the steering control) to be executed by the vehicle control system 100.
In the preceding vehicle following mode, the steering control and the speed control are performed in different manners, depending on detectability of opposing lane edges, and the presence or absence of a preceding vehicle. Here, the term “opposing lane edges” means opposing edges (a demarcation line such as a white road line, a road edge, an edge stone, a median strip, a guardrail or the like) of a lane in which the vehicle 1 is traveling, i.e., borderlines with respect to a neighboring lane and sidewalk, or the like. The ECU 10 is operable, when serving as a traveling road edge detection part, to detect the opposing lane edges from the image data about the images taken by the vehicle-mounted camera 21. Alternatively, the ECU 10 may be configured to detect the opposing lane edges from the map information of the navigation system 30. However, for example, in a situation where the vehicle 1 is traveling on the plain on which there is no traffic lane, instead of on a well-maintained road, or in a situation where reading of the image data from the vehicle-mounted camera 21 is bad, there is a possibility of failing to detect the opposing lane edges.
As above, in this embodiment, the ECU 10 is configured to serve as the traveling road edge detection part. Alternatively, the vehicle-mounted camera 21 may be configured to detect the opposing lane edges to serve as the traveling road edge detection part, or may be configured to detect the opposing lane edges in cooperation with the ECU 10 to serve as the traveling road edge detection part.
Further, the ECU 10 is operable, when serving as a preceding vehicle detection part, to detect a preceding vehicle, based on the image data from the vehicle-mounted camera 21, and the measurement data from the millimeter-wave radar 22. Specifically, the ECU 10 is operable to detect a second vehicle which is traveling ahead of the vehicle 1, as a preceding vehicle, based on the image data from the vehicle-mounted camera 21. Further, in this embodiment, the ECU 10 is operable, when the inter-vehicle distance between the vehicle 1 and the second vehicle is determined to be equal to or less than a given value (e.g., 400 to 500 m), based on the measurement data from the millimeter-wave radar 22, to detect the second vehicle as a preceding vehicle.
As above, in this embodiment, the ECU 10 is configured to serve as the preceding vehicle detection part. Alternatively, the vehicle-mounted camera 21 may be configured to detect a second vehicle which is traveling ahead of the vehicle 1 to serve as the preceding vehicle detection part, or the preceding vehicle detection part may be composed of not only the ECU 10 but also the vehicle-mounted camera 21 and the millimeter-wave radar 22.
Firstly, in a situation where the opposing lane edges are detected, the steering control is performed such that the vehicle 1 is steered to travel along approximately the middle of the lane, and the speed control is performed such that the vehicle 1 maintains a setup vehicle speed (constant speed) preliminarily set by the driver through the use of the setting vehicle speed input part 37 or by the system 100 based on given processing. Here, when the setup vehicle speed is greater than a speed limit (which is determined according to a speed sign or the curvature of a curve), priority is given to the speed limit, so that the vehicle speed of the vehicle 1 is limited to the speed limit. When the speed limit is determined according to the curvature of a curve, it is calculated by a given calculation formula, wherein it is set to a lower value as the curvature of the curve becomes larger (a curvature radius of the curve becomes smaller).
Further, when the setup vehicle speed of the vehicle 1 is greater than the vehicle speed of a preceding vehicle, the speed control is performed such that the vehicle 1 follows the preceding vehicle while maintaining an inter-vehicle distance appropriate to a follow-up vehicle speed. Then, when the preceding vehicle being followed by the vehicle 1 disappears from ahead of the vehicle 1 due to lane change or the like, the speed control is performed such that the vehicle 1 maintains the setup vehicle speed, again.
Secondly, in a situation where no opposing lane edges are detected, and there is a preceding vehicle, the steering control is performed such that the vehicle 1 follows a traveling trajectory of the preceding vehicle, and the speed control is performed such that the vehicle 1 follows the speed of the preceding vehicle on the traveling trajectory.
Thirdly, in a situation where no opposing lane edges are detected, and there is no preceding vehicle (in a situation where it is unable to detect any demarcation line and follow any preceding vehicle), it is unable to determine a traveling position on a traveling road. In this situation, the driver manually controls vehicle steering and vehicle speed by manipulating the steering wheel, and the accelerator pedal and/or brake pedal so as to maintain or change a current traveling behavior (steering angle, yaw rate, vehicle speed, acceleration, or the like) according to the will of the driver.
In the preceding vehicle following mode, irrespective of the presence or absence of a preceding vehicle, and the detectability of opposing lane edges, the after-mentioned obstacle avoidance control (speed control and steering control) is additionally and automatically executed.
The lane-keep control mode is an automatic steering control mode in which the steering control is performed such that the vehicle 1 is steered to travel along approximately the middle of a lane, i.e., which involves the automatic steering control to be executed by the vehicle control system 100, but does not involve the speed control. Thus, the lane-keep control mode is workable only in the situation where the opposing lane edges are detected. In this mode, the driver can control the vehicle speed according to the depression amount of the accelerator pedal. That is, the lane-keep control mode is equivalent to a mode in which the driver manually performs speed control by himself/herself in the situation where the opposing lane edges are detectable in the preceding vehicle following mode.
The automatic speed control mode is a mode in which the speed control is performed such that the vehicle 1 maintains a given setup vehicle speed (constant speed) preliminarily set by the driver or the system 100, and involves the automatic speed control (the engine control and/or the brake control) and the obstacle avoidance control (speed control) to be executed by the vehicle control system 100, but does not involves the steering control. In this automatic speed control mode, although the vehicle 1 is controlled to travel while maintaining the setup vehicle speed, the driver can increase the vehicle speed beyond the setup vehicle speed by depressing the accelerator pedal. Further, when the driver performs brake manipulation, priority is given to the will of the driver, and therefore the vehicle 1 is decelerated from the setup vehicle speed. Further, when the vehicle 1 catches up to a preceding vehicle, the speed control is performed such that the vehicle 1 follows the preceding vehicle while maintaining an inter-vehicle distance appropriate to a follow-up vehicle speed, and then when the preceding vehicle disappears, the speed control is performed such that the follow-up vehicle speed is returned to the setup vehicle speed.
The speed limiting mode is a mode in which the speed control is performed to prevent the vehicle speed of the vehicle 1 from exceeding a speed limit (legal speed limit) designated by a speed sign or the setup vehicle speed set by the driver, and involves the automatic speed control (engine control) to be executed by the vehicle control system 100. With regard to the legal speed limit, the ECU 10 may be configured to subject image data about an image of a speed sign or a speed marking on a road surface taken by the vehicle-mounted camera 21, to image recognition processing, to identify the legal speed limit, or may be configured to receive information regarding the legal speed limit from outside via a wireless communication. In the speed limiting mode, even when the driver depresses the accelerator pedal so as to increase the vehicle speed beyond the speed limit or the setup vehicle speed, the vehicle speed of the vehicle 1 is increased only up to the speed limit or the setup vehicle speed.
The basic control mode is a mode (off mode) in which none of the driving support modes is selected through the driver manipulation unit 35, and the automatic steering control and speed control are not executed by the vehicle control system 100. However, the basic control mode is configured to execute an automatic anti-collision control. In this anti-collision control, when the vehicle 1 encounters a situation where it is likely to collide with a preceding vehicle or the like, the brake control is automatically executed to avoid the collision. It should be noted that the automatic anti-collision control is also executed in the preceding vehicle following mode, the lane-keep control mode, the automatic speed control mode, and the speed limiting mode, in the same manner.
Further, the after-mentioned obstacle avoidance control (only the speed control, or only the steering control, or the speed control and the steering control) is also executed in the lane-keep control mode, the automatic speed control mode, the speed limiting mode and the basic control mode.
Next, with reference to
Each of the traveling courses (first to third traveling courses) in
For the sake of facilitating understanding, the following description will be made based on an example in which each of the traveling courses is calculated on the assumption that the vehicle 1 travels on a road 5 consisting of a straight section 5a, a curve section 5b, a straight section 5c. The road 5 comprises left and right lanes 5L, 5R. Assume that, at a present time, the vehicle 1 travels on the lane 5L in the straight section 5a.
As shown in
The ECU 10 is operable to execute the image recognition processing for image data about images around the vehicle 1 taken by the vehicle-mounted camera 21, to detect opposing lane edges 6L, 6R. The opposing lane edges are a demarcation line (white road line or the like), and a road shoulder or the like, as mentioned above. Further, the ECU 10 is operable, based on the detected opposing lane edges 6L, 6R, to calculate a lane width W of the lane 5L and the curvature radius L in the curve section 5b. Alternatively, the ECU 10 may be configured to acquire the lane width W and the curvature radius L from the map information of the navigation system 30. Further, the ECU 10 is operable to read, from the image data, a speed limit indicated by a speed sign S or on the road surface. Alternatively, the ECU 10 may be configured to acquire the speed limit from outside via a wireless communication, as mentioned above.
With regard to the straight sections 5a, 5c, the ECU 10 is operable to set a plurality of target positions P1_k of the first traveling course R1 to enable a vehicle width directional center (e.g., the position of the center of gravity) of the vehicle 1 to pass through the widthwise middle between the opposing lane edges 6L, 6R.
On the other hand, with regard to the curve section 5b, the ECU 10 is operable to maximally set a displacement amount Ws toward the in-side from the widthwise middle position of lane 5L at a longitudinal middle position P1_c of the curve interval 5b. This displacement amount Ws is calculated based on the curvature radius L, the lane width W, and a width dimension D of the vehicle 1 (prescribed values stored in the memory of the ECU 10). Then, the ECU 10 is operable to set the plurality of target positions P1_k of the first traveling course R1 in such a manner as to smoothly connect the longitudinal middle position P1_c of the curve section 5b to the widthwise middle position of each of the straight sections 5a, 5b. Here, it should be understood that the first traveling course R1 may also be offset toward the in-side in the straight sections 5a, 5c at positions just before entering the curve section 5b and just after exiting the curve section 5b.
Basically, a target speed V1_k at each of the target positions P1_k of the first traveling course R1 is set to a given setup vehicle speed (constant speed) preliminarily set by the driver through the use of the setting vehicle speed input part 37 of the driver manipulation unit 35 or by the system 100. However, when this setup vehicle speed exceeds the speed limit acquired from a speed sign S or the like, or the speed limit determined according to the curvature radius L of the curve section 5b, the target speed V1_k at each of the target positions P1_k on the traveling course is limited to a lower one of the two speed limits. Further, the ECU 10 is operable to correct the target positions P1_k and the target speeds V1_k, according to a current behavior state (i.e., vehicle speed, acceleration, yaw rate, steering angle, lateral acceleration, etc.) of the vehicle 1. For example, when a current value of the vehicle speed is largely different from the setup vehicle speed, the target speed is corrected so as to enable the vehicle speed to come close to the setup vehicle speed.
As shown in
As shown in
The ECU 10 is operable, based on a steering angle, a yaw rate and a lateral acceleration of the vehicle 1, to calculate target positions P3_k of the third traveling course R3 having the distance corresponding to the given time period. However, in the situation where the opposing lane edges are detected, the ECU 10 is operable to correct the target positions P3_k so as to prevent the calculated third traveling course R3 from coming close to or intersecting with any of the lane edges.
Further, the ECU 10 is operable, based on current values of the vehicle speed and the acceleration of the vehicle 1, to calculate a target speed V3_k of the third traveling course R3 having the distance corresponding to the given time period. Here, when the target speed V3_k exceeds the speed limit acquired from the speed sign S or the like, the target speed V3_k may be corrected so as not to exceed the speed limit.
Next, with reference to
When the preceding vehicle following mode is selected in a situation where the opposing lane edges are detected, the first traveling course is applied, irrespective of the presence or absence of a preceding vehicle. In this case, the setup vehicle speed set through the use of the setting vehicle speed input part 37 is used as the target speed.
On the other hand, when the preceding vehicle following mode is selected in a situation where the opposing lane edges are not detected, but a preceding vehicle is detected, the second traveling course is applied. In this case, the target speed is set according to the vehicle speed of the preceding vehicle. Further, when the preceding vehicle following mode is selected in a situation where neither the opposing lane edges nor a preceding vehicle is detected, the third traveling course is applied.
When the lane-keep control mode is selected in the situation where the opposing lane edges are detected, the first traveling course is applied. However, the target speed is set based on the vehicle speed estimated from a current traveling behavior of the vehicle 1. On the other hand, when the lane-keep control mode is selected in the situation where the opposing lane edges are not detected, the third traveling course is applied.
When the automatic speed control mode is selected, the third traveling course is applied. In the automatic speed control mode in which the speed control is automatically executed as mentioned above, the setup speed set through the use of the setting vehicle speed input part 37 is used as the target speed. Further, the driver manually controls vehicle steering by manipulating the steering wheel.
When the speed limiting mode is selected, the third traveling course is also applied. In the speed limiting mode in which the speed control is automatically executed as mentioned above, the target speed is set according to the depression amount of the accelerator pedal by the driver, within the speed limit. Further, the driver manually controls vehicle steering by manipulating the steering wheel.
When the basic control mode (off mode) is selected, the third traveling course is applied. The basic control mode is basically the same as the speed limiting mode in a state in which no speed limit is set.
Next, with respect to
In
Generally, when passing (or overtaking) an obstacle (e.g., a preceding vehicle, a parked vehicle, or a pedestrian) on or near a road, the driver of the vehicle 1 keeps a given clearance or distance (lateral distance) between the vehicle 1 and the obstacle in a lateral direction orthogonal to a traveling direction of the vehicle 1, and reduces the vehicle speed to a value at which the driver feels safe. Specifically, in order to avoid dangers such as a situation where a preceding vehicle suddenly changes a course, a situation where a pedestrian comes out from a blind spot of an obstacle, and a situation where a door of a parked vehicle is suddenly opened, the relative speed with respect to the obstacle is set to a lower value as the clearance becomes smaller.
Further, generally, when the vehicle 1 is approaching a preceding vehicle from behind the preceding vehicle, the driver of the vehicle 1 adjusts the vehicle speed (relative speed) according to an inter-vehicle distance (longitudinal distance) along the travelling direction. Specifically, when the inter-vehicle distance is relatively large, an approaching speed (relative speed) is maintained relatively high. However, when the inter-vehicle distance becomes relatively small, the approaching speed is set to a lower value. Subsequently, at a given inter-vehicle distance, the relative speed between the two vehicles is set to zero. This action is the same even when the preceding vehicle is a parked vehicle.
As above, the driver drives the vehicle 1 in such a manner as to avoid dangers while taking into account a relationship between the distance (including the lateral distance and the longitudinal distance) between an obstacle and the vehicle 1, and the relative speed therebetween.
Therefore, in this embodiment, as shown in
As can be understood from
Here, the speed distribution area 40 does not necessarily have to be set over the entire circumference of the obstacle, but may be set at least in a region behind the obstacle and on one (in
As shown in
In the example illustrated in
In this embodiment, Vlim is defined as a quadratic function of X, as mentioned above. Alternatively, Vlim may be defined as another function (e.g., a linear function). Further, the allowable upper limit Vlim has been described about a region thereof in the lateral direction of the obstacle with reference to
The speed distribution area 40 can be set based on various parameters. Examples of the parameter may include the relative speed between the vehicle 1 and an obstacle, the type of obstacle, the traveling direction of the vehicle 1, a moving direction and a moving speed of the obstacle, the length of the obstacle, and the absolute speed of the vehicle 1. That is, based on these parameters, the coefficient k and the safe distance D0 can be selected.
In this embodiment, the obstacle includes a vehicle, a pedestrian, a bicycle, a cliff, a trench, a hole and a fallen object. The vehicle can be classified into a passenger vehicle, a truck, and a motorcycle. The pedestrian can be classified into an adult, a child and a group.
As shown in
Further, the ECU 10 operates to calculate the position and the relative speed of the obstacle (parked vehicle 3) with respect to the vehicle 1, and absolute speed of the obstacle, based on the measurement data from the millimeter-wave radar 22 and vehicle speed data from the vehicle speed sensor 23. Here, the position of the obstacle includes an x-directional position (longitudinal distance) along the traveling direction of the vehicle 1, and a y-directional position (lateral distance) along the lateral direction orthogonal to the traveling direction.
The ECU 10 operates to set the speed distribution area 40 with respect to each of one or more detected obstacles (in
Specifically, in a situation where, if the vehicle 1 travels along the target traveling course, the target speed exceeds the allowable upper limit defined in the speed distribution area 40, at a certain target position, the target speed is reduced without changing the target position (course Rc1 in
For example,
When the vehicle 1 travels along the target traveling course R, it will cut across the constant relative speed lines d, c, c, d of the speed distribution area 40, in this order. That is, the vehicle 1 being traveling at 60 km/h enters a region inside the constant relative speed line d (allowable upper limit Vlim=60 km/h). Thus, the ECU 10 operates to correct the target traveling course R so as to restrict the target speed at each target position of the target traveling course R to the allowable upper limit Vlim or less, thereby forming the corrected target traveling course (corrected traveling course candidate) Rc1. Specifically, in the corrected target traveling course Rc1, as the vehicle 1 approaches the parked vehicle 3, the target speed is reduced to become equal to or less than the allowable upper limit Vlim at each target position, i.e., gradually reduced to less than 40 km/h, and then, as the vehicle 1 travels away from the parked vehicle 3, the target speed is gradually increased to 60 km/h as the original speed.
The corrected target traveling course (corrected traveling course candidate) Rc3 is a course which is set such that the vehicle 1 travels outside the constant relative speed line d (which corresponds to a relative speed of 60 km/h), instead of changing the target speed (60 km/h) of the target traveling course R. In this case, the ECU 10 operates to correct the target traveling course R such that the target position is changed to a point on or outside the constant relative speed line d, while maintain the target speed of the target traveling course R, thereby forming the corrected target traveling course Rc3. Thus, the target speed of the corrected target traveling course Rc3 is maintained at 60 km/h as the target speed of the target traveling course R.
The corrected target traveling course (corrected traveling course candidate) Rc2 is a course set by changing both the target position and the target speed of the target traveling course R. In the corrected target traveling course Rc2, instead of maintaining the target speed at 60 km/h, the target speed is gradually reduced as the vehicle 1 approaches the parked vehicle 3, and then gradually increased to 60 km/h as the original speed, as the vehicle 1 travels away from the parked vehicle 3.
The correction to be achieved by changing only the target speed without changing the target position of the target traveling course R, as in the corrected target traveling course Rc1, can be applied to a driving support mode which involves the speed control but does not involve the steering control (e.g., the automatic speed control mode, the speed limiting mode, and the basic control mode).
Further, the correction to be achieved by changing only the target position without changing the target speed of the target traveling course R, as in the corrected target traveling course Rc3, can be applied to a driving support mode which involves the steering control (e.g., the preceding vehicle following mode, and the lane-keep control mode).
Further, the correction to be achieved by changing both the target position and the target speed of the target traveling course R, as in the corrected target traveling course Rc2, can be applied to a driving support mode which involves the speed control and the steering control (e.g., the preceding vehicle following mode).
As shown in
The ECU 10 stores the evaluation function J, a limiting condition and a vehicle model in the memory. The ECU 10 is operable, in the traveling course correction processing, to derive one corrected traveling course which is the smallest in terms of the evaluation function, while meeting the limiting condition and the vehicle model (optimization processing).
The evaluation function J has a plurality of evaluation factors. In this embodiment, the evaluation factors are functions for evaluation a difference between the target traveling course and each of a plurality of corrected traveling course candidates, in terms of, e.g., speed (longitudinal and lateral speeds), acceleration (longitudinal and lateral accelerations), acceleration change rate (longitudinal and lateral acceleration change rates), yaw rate, lateral offset with respect to the middle of a lane, vehicle angle, steering angle, and other software limitations.
The evaluation factors include evaluation factors regarding a longitudinal behavior of the vehicle 1 (longitudinal evaluation factors: longitudinal speed, longitudinal acceleration, longitudinal acceleration rate, etc.), and evaluation factors regarding a lateral behavior of the vehicle 1 (lateral evaluation factors: lateral speed, lateral acceleration, lateral acceleration rate, yaw rate, lateral offset with respect to the middle of a lane, vehicle angle, steering angle, etc.).
Specifically, the evaluation function J is expressed as the following formula:
In this formula, Wk (Xk−Xrefk)2 denotes each of the evaluation factors, wherein: Xk denotes a physical value of the corrected traveling course candidate in regard to each of the evaluation factors; Xrefk denotes a physical value of the target traveling course (before correction) in regard to a corresponding one of the evaluation factors; and Wk denotes a weighting factor for the corresponding one of the evaluation factors (e.g., 0≤Wk≤1) (where k is an integer of 1 to n). Thus, in this embodiment, the evaluation function J is equivalent to a value obtained by: calculating differences in respective physical amounts of n evaluation factors between a corrected traveling course candidate and a target traveling course (before correction) calculated on the assumption that there is no obstacle; weighting respective square values of the differences; and summing the weighted values over a traveling course distance corresponding to a given time period N (e.g., N=3 sec)
The limiting condition includes at least one limiting factor for limiting the behavior of the vehicle 1. The limiting factor is associated directly or indirectly with either one of the evaluation factors. Thus, the behavior (i.e., the physical value of the associated evaluation factor) is limited by the limiting condition, so that it is possible to early converge the optimization processing based on the evaluation function J, thereby shortening a calculation time period. The limiting condition is set differently according to each of the driving support modes.
In this embodiment, examples of the limiting factor include speed (longitudinal and lateral speeds), acceleration (longitudinal and lateral accelerations), acceleration change rate (longitudinal and lateral acceleration change rates), temporal deviation of vehicle speed, lateral offset with respect to the middle of a lane, temporal deviation of inter-vehicle distance, steering angle, steering angular speed, steering torque, steering torque rate, yaw rate, and vehicle angle. With respect to each of the above limiting factors, an allowable numerical rage is set (e.g., −4 m/s2 longitudinal acceleration≤3 m/s2, −5 m/s2≤lateral acceleration≤5 m/s2). For example, the longitudinal and lateral accelerations exerting a large influence on riding comfort can be limited by the limiting condition. In this case, it is possible to limit maximum values of longitudinal G and lateral G in the corrected traveling course.
The vehicle model is designed to define physical movements of the vehicle 1, and expressed as the following motion equations. In this embodiment, this vehicle model is a two-wheel vehicle model as shown in
In
The ECU 10 is operable, based on the target traveling course, the limiting condition, the vehicle model, the obstacle information, etc., to derive one corrected traveling course which is the smallest in terms of the evaluation function J, from among a plurality of corrected traveling course candidates. That is, in the traveling course correction processing, the ECU 10 functions as a solver for outputting a solution of an optimization problem. Thus, the corrected traveling course to be derived as an optimal solution is selected on conditions that it most conforms to (is closest to) the target traveling course before correction, while allowing the vehicle 1 to ensure an appropriate distance and relative speed with respect to an obstacle.
In this embodiment, the evaluation factors of the evaluation function are set differently accordingly to each of the driving support modes. Specifically, plural different sets of weighting factors Wk (k=1 to n) for the evaluation factors are formed correspondingly to respective ones of the driving support modes, and stored in the memory of the ECU 10. Thus, in response to receiving of the driving support mode selection signal, the ECU 10 operates to read a corresponding one of the sets of weighting factors, so that it is possible to use a different evaluation function J with respect to each driving support mode.
In the automatic speed control mode, the driver relies on the vehicle 1 for the speed control, but has the will to perform steering manipulation by himself/herself. That is, the driver does not want automatic intervention in the steering manipulation. Therefore, the weighting factor for the evaluation factor regarding the lateral behavior of the vehicle is set to a smaller value than that of the evaluation factor regarding the longitudinal behavior of the vehicle (e.g., set to zero). That is, a contribution rate of the evaluation factor regarding the lateral behavior of the vehicle, to the evaluation function J, is set to be relatively low. As a result, the vehicle control by the ECU 10 is performed with an emphasis on the speed control, and is dependent on the driver for the steering control.
In the lane-keep control mode (automatic steering control mode), the driver relies on the vehicle 1 for the steering control, but has the will to perform speed manipulation (accelerator and brake manipulations) by himself/herself. That is, the driver does not want automatic intervention in the speed manipulation. Therefore, the weighting factor for the evaluation factor regarding the longitudinal behavior of the vehicle is set to a smaller value than that of the evaluation factor regarding the lateral behavior of the vehicle 1 (e.g., set to zero). That is, a contribution rate of the evaluation factor regarding the longitudinal behavior of the vehicle 1, to the evaluation function J, is set to be relatively low. As a result, the vehicle control by the ECU 10 is performed with an emphasis on the steering control, and is dependent on the driver for the speed control.
In the preceding vehicle following mode which is an automatic speed and steering control mode, the driver has the will to rely on the vehicle 1 for the speed control and the steering control. Therefore, the weighting factors for the evaluation factors regarding both the longitudinal and lateral behaviors of the vehicle are set to appropriate values. Specifically, the weighting factor for the evaluation factor regarding the lateral behavior of the vehicle 1 is set to be greater than that for the automatic speed control mode, and the weighting factor for the evaluation factor regarding the longitudinal behavior of the vehicle 1 is set to be greater than that for the automatic steering control mode. As a result, the vehicle control by the ECU 10 is performed with an emphasis on both the speed control and the steering control.
In the basic control mode which is a mode in which the speed control and the steering control are not automatically executed, the driver has the will to perform the speed control and the steering control by himself/herself. In the basic control mode, the target traveling course is calculated just in case of collision with a preceding vehicle or an obstacle (e.g., in order to allow the vehicle 1 to take over manipulations in case of emergency). Therefore, in the basic control mode, the weighting factor for the evaluation factor regarding the longitudinal behavior of the vehicle 1 is set to a larger value than that of the evaluation factor regarding the lateral behavior of the vehicle 1. That is, a contribution rate of the evaluation factor regarding the longitudinal behavior of the vehicle 1, to the evaluation function J, is set to be relatively high. As a result, the vehicle control by the ECU 10 is performed with a greater emphasis on the speed control than the steering control.
In this embodiment, the driver can revise the evaluation function J, using the revision part 38 of the driver manipulation unit 35. Through this revision, it is possible to revise the weight factors Wk (k=1 to n) for the evaluation factors to change the overall weighting of the evaluation factors. For this purpose, the revision part 38 comprises a plurality of switches capable of revising respective weighting factors for all the evaluation factors. For example, through each of the switches, the weighting factor Wk for a corresponding one of the evaluation factors can be changed stepwisely at a given change amount ΔA (ΔA=0.1).
The ECU 10 (target traveling course calculation part 10a) is operable, in response to receiving of the revision request signal output as a result of manipulation of the revision part 38, to revise the weighting factors Wk (k=1 to n) for the evaluation factor J, stored in the memory. For example, the weighting factors Wk set according to a selected one of the driving support modes are changed to revised values in response to the revision request signal.
The revision part 38 may comprise a lateral G (lateral motion)-reducing switch (corresponding to the corrected traveling course candidate Rc1), a speed reduction-suppressing switch (corresponding to the corrected traveling course candidate Rc3), and an intermediate switch (corresponding to the corrected traveling course candidate Rc2). When the intermediate switch is selected, the weighting factors Wk set according to a selected one of the driving support modes are used directly. In this case, a revision request signal indicative of requiring no revision is output.
On the other hand, when the lateral G (lateral motion)-reducing switch is selected, the revision request signal is output to cause (one or more of) the weighting factors for the lateral evaluation factor to be increased by a given change amount ΔW (e.g., ΔW=0.2), and cause (one or more of) the weighting factors for the longitudinal evaluation factor to be reduced by the given change amount ΔW. As a result, a contribution rate of the lateral evaluation factor is increased, and a contribution rate of the longitudinal evaluation factor is reduced.
Further, when the speed reduction-suppressing switch is selected, the revision request signal is output to cause (one or more of) the weighting factors for the longitudinal evaluation factor to be increased by the given change amount ΔW, and cause (one or more of) the weighting factors for the lateral evaluation factor to be reduced by the given change amount ΔW. As a result, a contribution rate of the longitudinal evaluation factor is increased, and a contribution rate of the lateral evaluation factor is reduced.
In this embodiment, a numerical range in which the weighting factors for the evaluation factors are permitted to be revised may be set differently according to a selected one of the driving support modes. For example, in the automatic speed control mode, the weighting factors for the longitudinal evaluation factor may be permitted to be revised in a range of a given first threshold or more (e.g., 0.6≤Wk≤1), and the weighting factors for the lateral evaluation factor may be permitted to be revised in a range of a given second threshold or less (e.g., 0≤Wk≤0.4).
On the other hand, in the lane-keep control mode, the weighting factors for the lateral evaluation factor may be permitted to be revised in a range of a given first threshold or more (e.g., 0.6≤Wk≤1), and the weighting factors for the longitudinal evaluation factor may be permitted to be revised in a range of a given second threshold or less (e.g., 0≤Wk≤0.4). Further, in the preceding vehicle following mode, the weighting factors for the longitudinal evaluation factor and the lateral evaluation factor may be permitted to be revised in a range between a given third threshold and a given fourth threshold (e.g., 0.2≤Wk≤0.8).
In this embodiment, the ECU 10 (target traveling course calculation part 10a) is operable to receive the environmental information from the environmental information sensor 39, and revise the evaluation function J according to the received environmental information. Through this revision, the weighting factors Wk are revised in the above manner.
For example, in a case where the environment sensor 39 outputs a rainfall amount (snowfall amount) as the environmental information, the ECU 10 is operable to determine slipperiness of a road surface (or lowness of a friction coefficient) according to the rainfall amount (or snowfall amount), and increase the weighting factors for the lateral evaluation factor (e.g., lateral acceleration) by a given change amount ΔW (e.g., ΔW=0.1). Thus, a contribution rate of the lateral evaluation factor can be increased. Here, in addition to the rainfall amount (or snowfall amount), ambient temperature and humidity may be added to determination conditions to determine the slipperiness of the road surface. As above, the ECU 10 can revise the evaluation function J by always monitoring environmental conditions using the environmental information.
In this embodiment, the ECU 10 (target traveling course calculation part 10a) is operable to acquire the environmental information from the environment sensor 39, and change the limiting condition according to the acquired environmental information. For example, in the case where the environment sensor 39 outputs a rainfall amount (or snowfall amount) as the environmental information, the ECU 10 is operable to, e.g., narrow an allowable numerical range of longitudinal acceleration, according to the rainfall amount (or snowfall amount). For example, an upper limit of longitudinal acceleration is reduced by Δa (e.g., Δa=1 m/s2), and a lower limit of longitudinal acceleration is increased by the Δa. Thus, it is possible to suppress quick acceleration and quick deceleration during rainy weather, as compared with during clear weather. Here, in addition to the rainfall amount (or snowfall amount), ambient temperature and humidity may be added to determination conditions. As above, the ECU 10 can change the limiting condition by always monitoring environmental conditions using the environmental information.
With a view to preventing an erroneous changing manipulation, the vehicle control system 100 according to this embodiment is configured to prevent change of the limiting condition by a driver. Thus, the limiting condition cannot be changed by manipulation of the driver manipulation unit 35.
Next, with reference to
The ECU 10 operates to repeatedly execute the processing flow in
Subsequently, the ECU 10 operates to execute given information detection processing (S12), using a variety of information acquired in the information acquisition processing (S11). In the information detection processing, the ECU 10 operates to detect, from the current vehicle position information, the map information and the sensor information, the traveling road information regarding a shape of a traveling road around and ahead of the vehicle 1 (the presence or absence of a straight section and a curve section, the length of each of the sections, the curvature radius of the curve section, a lane width, opposing lane edges, the number of lanes, the presence or absence of an intersection, a speed limit determined by the curvature of a curve, etc.), traveling regulation information (legal speed limit, red light, etc.), and the preceding vehicle trajectory information (the position and the vehicle speed of a preceding vehicle) (S12a).
Further, the ECU 10 operates to: detect, from the switch information, vehicle manipulation information regarding vehicle manipulation by the driver (steering angle, accelerator pedal depression amount, brake pedal depression amount, etc.) (S12b); and detect, from the switch information and the sensor information, traveling behavior information regarding the behavior of the vehicle 1 (vehicle speed, longitudinal acceleration, lateral acceleration, yaw rate, etc.) (S12c).
Subsequently, the ECU 10 operates to execute traveling course calculation processing, based on information obtained by calculation (S13). In the traveling course calculation processing, the first traveling course, the second traveling course and the third traveling course are calculated as mentioned above.
Further, the ECU 10 operates to execute the traveling course correction processing for correcting the target traveling course in the after-mentioned manner (S14). Specifically, in the traveling course correction processing, the ECU 10 operates to correct the target traveling course, based on the obstacle information (e.g., information about the parked vehicle 3 illustrated in
Subsequently, the ECU 10 operates to output, according to the selected driving support mode, a request signal to a concerned control sub-system (the engine control system 31, the brake control system 32 and/or the steering control system 33) so as to allow the vehicle 1 to travel on the finally calculated traveling course (S15). Specifically, the ECU 10 operates as a traveling behavior control part to output the request signal, according to target control amounts of the engine, the braking device and the steering device, determined by the calculated traveling course (corrected traveling course).
Next, with reference to
First of all, the ECU 10 operates to determine, based on the driving support mode selection signal received from the mode selection switch 36, whether or not the driver selects the preceding vehicle following mode (S21).
When the preceding vehicle following mode is determined to be selected (S21: YES), the ECU 10 operates to determine, based on the sensor information, etc., whether or not opposing lane edges are detected (S22). When opposing lane edges are determined to be detected (S22: YES), the ECU 10 operates to calculate the first traveling course as the target traveling course. Here, when a preceding vehicle is detected, the vehicle speed of the preceding vehicle is used as the target speed. On the other hand, when no preceding vehicle is detected, the setup speed is used as the target speed.
In the above first traveling course calculation process, the ECU 10 operates to calculate the traveling course R1 having a distance corresponding to a given time period (e.g., 3 seconds), based on the setup vehicle speed, the opposing lane edges, the lane width, the speed limit, the vehicle speed, the longitudinal acceleration, the yaw rate, the steering angle, the lateral acceleration, etc. The target positions of the traveling course R1 are set to allow the vehicle 1 to travel along approximately the middle of a lane in a straight section, and travel on the in-side of a curve in a curve section to have a larger turning radius. Further, the target speeds of the traveling course R1 is set such that a lowest one of the setup vehicle speed, a speed limit designated by a traffic sign, and a speed limit determined by the curvature of the curve becomes a maximum speed thereof.
On the other hand, in the S22, when no opposing lane edges are determined to be detected (S22: NO), the ECU 10 operates to determine whether or not a preceding vehicle is detected (S24).
When no opposing lane edges are determined to be detected, but a preceding vehicle is determined to be detected (S24: YES), the ECU 10 operates to calculate the second traveling course as the target traveling course (S25). In the above second traveling course calculation process, the ECU operates to calculate the traveling course R2 having a distance corresponding to the given time period, based on the preceding vehicle trajectory information (position and speed) acquired from the sensor information, etc., to allow the vehicle 1 to follow the behavior (position and speed) of the preceding vehicle, while maintaining a given inter-vehicle distance between the preceding vehicle and the vehicle 1, i.e., behind the preceding vehicle by a time period necessary to travel over the inter-vehicle distance.
On the other hand, in the S21, when the preceding vehicle following mode is determined not to be selected (S21: NO), the ECU 10 operates to determine whether or not the lane-keep control mode is selected (S26). When the lane-keep control mode is determined to be selected (S26: YES), the ECU 10 operates to determine, based on the sensor information, etc., whether or not opposing lane edges are detected (S28). When opposing lane edges are determined to be detected (S28: YES), the ECU 10 operates to calculate the first traveling course as the target traveling course (S29). In this case, the target speed is set based on a speed estimated from the current traveling behavior of the vehicle 1.
On the other hand, when the preceding vehicle following mode and the lane-keep control mode are determined not to be selected (S26: NO), or when the preceding vehicle following mode is determined to be selected, but none of the opposing lane edges and the preceding vehicle are determined to be detected (S24: NO) or when the lane-keep control mode is determined to be detected, but no opposing lane edges are determined to be detected (S28: NO), the ECU 10 operates to calculate the third traveling course as the target traveling course (S27). In the above third traveling course calculation process, the ECU operates to calculate, based on the vehicle manipulation information, the traveling behavior information, etc., the traveling course R3 having a distance corresponding to the given time period, assumed from the current behavior of the vehicle 1.
In this modification, when the preceding vehicle following mode is determined not to be selected (S21: NO), or when the preceding vehicle following mode is determined to be selected, but none of the opposing lane edges and the preceding vehicle are determined to be detected (S24: NO), the ECU 10 operates to calculate the third traveling course as the target traveling course (S27).
Next, with reference to
First of all, the ECU 10 operates to acquire obstacle information (the presence or absence, the position, the speed, etc., of a preceding vehicle or an obstacle), using a variety of information acquired in the information acquisition processing (S11) (S31).
Subsequently, the ECU 10 operates to determine whether or not an obstacle is detected (S32). When no obstacle is determined to be detected (S32: NO), the processing routine is completed. On the other hand, when an obstacle is determined to be detected (S32: YES), the ECU 10 operates to set the speed distribution area (see
Subsequently, the ECU 10 operates to read the evaluation function J, the limiting condition and the vehicle model, according to the sensor/switch information (e.g., the driving support mode selection signal) (S34). Subsequently, the ECU 10 operates to execute the optimization processing for the corrected traveling course, using the evaluation function J, based on the target traveling course calculated by the traveling course calculation processing (S13), the speed distribution area (S33), the evaluation function J, the limiting condition, the vehicle model, the sensor/switch information, etc. (S35). In this optimization processing, an evaluation value of the evaluation function J with respect to each of a plurality of corrected traveling course candidates is repeatedly calculated until an optimized corrected traveling course is derived. Then, one of the corrected traveling course candidates which is the smallest in terms of the evaluation value is output as the corrected traveling course.
Next, functions of the vehicle control device for use in the above embodiment will be described.
The vehicle control device (ECU) 10 for use in the above embodiment comprises a target traveling course calculation part 10a for calculating a target traveling course R of a vehicle 1, wherein the target traveling course calculation part 10 is configured to, upon detection of an obstacle (e.g., a second vehicle 3), execute traveling course correction processing (S14, S31 to S35) of correcting the target traveling course R so as to avoid the obstacle, wherein the target traveling course calculation part 10a is configured to, in the traveling course correction processing, correct the target traveling course R to calculate a plurality of corrected traveling course candidates for avoiding the obstacle; and evaluate the corrected traveling course candidates with respect to the target traveling course R by a given evaluation function J including a plurality of evaluation factors, to derive one corrected traveling course according to the evaluation, and wherein the target traveling course calculation part 10a is configured to revise the evaluation factors based on an external signal.
Thus, the ECU 10 for use in the above embodiment can correct the target traveling course to derive the corrected traveling course. Specifically, in the traveling course correction processing, one corrected traveling course is derived by evaluating the corrected traveling course candidates, using the evaluation function J including the plurality of evaluation factors. Further, the target traveling course calculation part 10a can operate to revise the evaluation factors in response to receiving an external signal. This makes it possible to revise the evaluation factor J according to traveling conditions to derive an adequate corrected traveling course.
In the above embodiment, the revision of the evaluation function J is to change weighting of the plurality of the evaluation factors. This makes it possible to perform the revision of the evaluation function readily and effectively.
The above embodiment, a revision part 38 is comprised to allow a driver to revise the evaluation factors of the evaluation function J, wherein the revision part 38 is configured to, when the driver manipulates the revision part 38, output a revision request signal as the external signal. Thus, the driver can manipulate the revision part 38 to revise the evaluation factors of the evaluation function J, according to a preference of the driver.
In the above embodiment, the plurality of evaluation factors include an evaluation factor regarding a longitudinal behavior of the vehicle 1, and an evaluation factor regarding a lateral behavior of the vehicle 1, wherein the revision part 38 is configured to revise the evaluation factor regarding the longitudinal behavior of the vehicle 1, and the evaluation factor regarding the lateral behavior of the vehicle 1. Thus, the evaluation factor regarding the longitudinal and lateral behaviors can be revised, so that it is possible to derive the corrected traveling course with an emphasis on one or both of vehicle speed and steering, according the preference of the driver.
In the above embodiment, when the vehicle 1 has a plurality of driving support modes, a numerical range in which the evaluation factors are permitted to be revised is set differently according to each of the driving support modes. This makes it possible to derive the corrected traveling course within an adequate range according to each of the driving support modes.
In the above embodiment, the target traveling course calculation part 10a is configured to, in the traveling course correction processing, derive the corrected traveling course so as to satisfy a given limiting condition for limiting a behavior of the vehicle 1, wherein it is configured to prevent change of the limiting condition by a driver. This makes it possible to prevent deterioration in safety due to erroneous change of the limiting condition by the driver.
In the above embodiment, an environment sensor 39 (environmental information acquisition part) is further comprised and configured to acquire environmental information regarding a weather or a traveling road state around the vehicle 1, wherein the target traveling course calculation part 10a is configured to receive, as the external signal, the environmental information from the environmental information acquisition part, and revise the evaluation factors according to the received environmental information. This makes it possible to automatically revise the evaluation factors in conformity to a change in environmental condition.
In the above embodiment, the target traveling course calculation part 10a is configured to, in the traveling course correction processing, derive the corrected traveling course so as to satisfy a given limiting condition for limiting a behavior of the vehicle 1, and an environment sensor 39 (environmental information acquisition part) is further comprised and configured to acquire environmental information regarding a weather or a traveling road state around the vehicle 1, wherein the target traveling course calculation part 10a is configured to revise the limiting condition according to the environmental information acquired by the environmental information acquisition part. This makes it possible to automatically revise the limiting condition in conformity to a change in environmental condition.
In the above embodiment, the target traveling course calculation part 10a is configured to, in the traveling course correction processing, set a speed distribution area 40 defining a distribution area of an allowable upper limit Vlim of a relative speed of the vehicle 1 with respect to the obstacle, in a direction at least from the obstacle toward the vehicle 1; and correct the target traveling course R to calculate the corrected traveling course candidates, such that the relative speed of the vehicle 1 with respect to the obstacle does not exceed the allowable upper limit Vlim in the speed distribution area 40.
Thus, the ECU 10 can define the speed distribution area 40 between the obstacle and the vehicle 1, and correct the target traveling course without exceeding the allowable upper limit Vlim of the relative speed defined by the speed distribution area 40, thereby calculating the corrected traveling course candidates. Thus, by using the speed distribution area 40, it becomes possible to reduce a feeling of strangeness to be given to a driver by the corrected traveling course.
In the above embodiment, the target traveling course calculation part 10a is configured to, in the traveling course correction processing, drive the corrected traveling course, using a given vehicle model defining physical motions of the vehicle 1. This makes it possible to derive the corrected traveling course which gives a less feeling of strangeness, and early converge optimization processing based on the evaluation function J.
In the above embodiment, the evaluation function J is expressed as a total value of differences in respective physical amounts of the evaluation factors between each of the corrected traveling course candidates and the target traveling course, wherein the target traveling course calculation part 10a is configured to, in the traveling course correction processing, select one of the corrected traveling course candidates which is smallest in terms of the total value. This makes it possible to derive a corrected traveling course having the smallest difference from the target traveling course, to the extent that does not exceed the allowable upper limit of the relative speed defined by the speed distribution area.
In the above embodiment, the evaluation factor regarding the longitudinal behavior of the vehicle 1 includes at least a longitudinal speed of the vehicle 1 or a longitudinal acceleration of the vehicle 1, and the evaluation factor regarding the lateral behavior of the vehicle 1 includes at least one of a lateral speed of the vehicle 1, a lateral acceleration of the vehicle 1, and a yaw rate of the vehicle 1.
In the above embodiment, the limiting condition includes at least one of speed, acceleration, acceleration change rate, steering angle, steering angular speed, and yaw rate
The above embodiment further comprises a traveling behavior control part to execute traveling behavior control processing (S15 in
| Number | Date | Country | Kind |
|---|---|---|---|
| 2017-165242 | Aug 2017 | JP | national |
| 2017-165244 | Aug 2017 | JP | national |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/JP2018/031084 | 8/23/2018 | WO | 00 |
