JP2011063106A - Vehicle controller and vehicle control method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a vehicle controller and a vehicle control method capable of generating a safe driving plan by using traveling information with a traveling record. <P>SOLUTION: A driving plan generation ECU 18, to which the traveling information with the traveling record of an own vehicle or other vehicle (including longitudinal Gx, lateral Gy, and positional information or the like) is input, estimates a road surface μ of a road as an object of the driving plan based on the longitudinal Gx and lateral Gy with the traveling record, calculates tire generation force based on an estimated road surface μ, and generates the driving plan under a condition of not exceeding the calculated tire generation force. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a vehicle control device and a vehicle control method, and more particularly to a vehicle control device and a vehicle control method for generating a travel locus.

  In recent years, with the advancement of intelligence technology and information technology of vehicles such as automobiles, vehicle control technology that supports driving and traveling of vehicles has been developed to a higher degree than before, and the driving burden on the driver of the vehicle has been reduced. Reduced and improved vehicle safety. For example, using on-vehicle radar, inter-vehicle communication technology, etc., automatically discovers leading vehicles and obstacles that exist in the traveling direction of the vehicle, and avoids them appropriately or maintains an appropriate inter-vehicle distance By using a technology that issues a warning to a person or controls the running / motion of the vehicle and a car navigation system using GPS (Global Positioning System), information on the current position of the vehicle and information on the surrounding road conditions are acquired. In addition, a technique for generating an operation plan (future travel trajectory) by referring to such information and a long-term desire of the driver (destination, arrival time, etc.) has been proposed. In order to generate an operation plan and control vehicle behavior, it is necessary to grasp a road surface friction coefficient (hereinafter referred to as “μ”) representing a road surface state.

  For example, in Patent Document 1, the control unit calculates a target behavior (a target longitudinal force Fx, a target yaw moment Mz) estimated mainly from a driver operation on the host vehicle, and sets the host vehicle 1 after a preset Δt seconds. An objective function L that represents a minimum value including the friction circle utilization rate μr (Δt), the total contact probability Rt (Δt) for all three-dimensional objects to be determined, and the target behavior correction amount δFv is set in advance. A technique has been proposed in which a target behavior correction amount δFv that minimizes the objective function L is calculated, a control amount is determined based on the target behavior and the target behavior correction amount δFv, and automatic brake control is executed based on the control amount. ing.

  However, in Patent Document 1, when the planned operation is performed based on the preview information, the road surface μ is fixed to “1”, and control in consideration of safety on the low μ road is separately required.

JP 2007-99166 A

  The present invention has been made in view of the above, and it is an object of the present invention to provide a vehicle control device and a vehicle control method capable of generating a safe driving plan using traveling information with a traveling record. And

  In order to solve the above-described problems and achieve the object, the present invention provides a travel information input unit that inputs travel information with a travel record of the host vehicle or another vehicle, and the travel information input by the travel information input unit. And an operation plan generating means for generating an operation plan based on the above.

  Further, according to a preferred aspect of the present invention, the travel information includes front and rear Gx, side Gy, and position information, and the operation plan generation unit is configured to determine a target road based on the front and rear Gx and side Gy. Estimating the road surface friction coefficient (hereinafter referred to as “friction coefficient” is μ), calculating the tire generation force based on the estimated road surface μ, and generating an operation plan under conditions that do not exceed the calculated tire generation force desirable.

Moreover, according to a preferable aspect of the present invention, it is desirable that the operation plan generation means estimates (front-rear Gx ² + lateral Gy ² ) ^1/2 as a road surface μ.

  Further, according to a preferred aspect of the present invention, the operation plan generation means calculates the reliability of the road surface μ based on the degree of nonlinearity of the vehicle and the tire, and the road surface μ where the calculated reliability of the road surface μ is equal to or less than a predetermined value. It is desirable to correct

  According to a preferred aspect of the present invention, it is desirable that the driving plan includes a vehicle speed and a steering angle.

  Moreover, according to a preferable aspect of the present invention, it is desirable that the travel plan generation unit generates an operation plan using an evaluation function.

  In order to solve the above-described problems and achieve the object, the present invention includes a travel information input process for inputting travel information having a travel record of the host vehicle or another vehicle, and a travel record input in the travel information input process. And an operation plan generation step for generating an operation plan based on the travel information.

  According to the present invention, driving information input means for inputting driving information with a driving record of the host vehicle or other vehicles, and driving plan generation for generating a driving plan based on the driving information input by the driving information input means. The vehicle control device capable of generating a safe driving plan using travel information with a track record of travel is provided.

FIG. 1 is a block diagram showing an example of a schematic configuration of a vehicle control device according to Embodiment 1 of the present invention. FIG. 2 is a diagram for explaining the relationship among the lateral Gy, the front and rear Gx, and the estimated road surface μ. FIG. 3 is a diagram for explaining the relationship among the lateral Gy, the front and rear Gx, and the estimated road surface μ. FIG. 4 is a flowchart for explaining an operation of collecting travel information of the operation plan generation ECU of FIG. FIG. 5 is a flowchart for explaining an operation in which the operation plan generation ECU generates an operation plan. FIG. 6 is a block diagram illustrating an example of a schematic configuration of the vehicle control device according to the second embodiment. FIG. 7 is a diagram for explaining an example of the reliability of the road surface μ. FIG. 8 is a diagram for explaining a method of correcting the road surface μ. FIG. 9 is a flowchart for explaining an operation of generating an operation plan by the operation plan generation ECU.

  Embodiments of a vehicle control device according to the present invention will be described below in detail with reference to the drawings. Note that the present invention is not limited to the embodiments. In addition, constituent elements in the following embodiments include those that can be easily assumed by those skilled in the art or that are substantially the same.

(Embodiment 1)
FIG. 1 is a block diagram illustrating an example of a schematic configuration of a vehicle control device mounted on a vehicle according to the first embodiment. The vehicle according to Embodiment 1 is configured to be capable of automatic driving (autonomous driving). As shown in FIG. 1, the vehicle control device 1 according to the first embodiment includes a camera device 11, a radar device 12, a host vehicle travel information input unit 14, a road information storage unit 15, and a car navigation device 16. A communication unit (another vehicle travel information input unit) 17, an operation plan generation ECU 18, a vehicle motion control ECU 19, an EPS (electric power steering) 20, an ECB (electronic brake device) 21, and an engine device 22. Yes.

  The camera device 11 includes a camera and an image processing device, detects left and right white lines on both sides of the travel lane, and outputs the detected positions (coordinates) of the left and right white lines to the driving plan generation ECU 18. . The operation plan generation ECU 18 calculates a line (center line) passing through the center of the vehicle from the positions of the left and right white lines, a curve radius of the center line, and the like.

  The radar device 12 uses a millimeter wave radar to detect the relative distance between the host vehicle and the perceptual object, and outputs the relative distance to the driving plan generation ECU 18. The millimeter wave radar emits a millimeter wave in a predetermined range in the traveling direction from the front surface of the host vehicle, and receives the millimeter wave reflected by the perceptual object TA existing in the traveling direction of the host vehicle. Then, the millimeter wave radar detects the actual relative distance Dr by calculating the distance from the millimeter wave radar to the perceived object TA of the host vehicle by measuring the time from emission to reception, and the driving plan generation ECU 18. Output to. The distance sensor is not limited to the millimeter wave radar. For example, the distance sensor is based on image data obtained by imaging the traveling direction of the host vehicle CA using an imaging device such as a radar or a CCD camera using a laser or an infrared ray. An image recognition device that calculates the distance may be used.

  The host vehicle travel information detection unit 14 includes, for example, a G sensor that detects front and rear Gx and lateral Gy of the vehicle, a vehicle speed sensor that detects a travel speed (vehicle speed) of the host vehicle, right wheels, and left wheels as travel information of the host vehicle. A wheel speed sensor for detecting the wheel speed of the (front wheel and / or rear wheel), a yaw rate sensor for detecting the yaw rate (rotational angular velocity around the vertical axis of the center of gravity of the vehicle), a steering angle sensor for detecting the steering angle, such as an artificial satellite It is configured with a GPS receiver that receives positioning signals such as GPS (Global Positioning System) signals for measuring the position of the vehicle by using it and detects position information that is the absolute position coordinates of the host vehicle. The detected travel information of the host vehicle is output to the driving plan generation ECU 18. The traveling information includes front and rear Gx, lateral Gy, vehicle speed, yaw rate, steering angle, wheel speed, position information, and the like.

  The road information storage unit 15 stores map data, node information related to the road, and curve information as road data. The node information is, for example, coordinate point data for grasping the road shape. For example, in addition to the start and end points of a curve set on a link (that is, a line connecting each node), information on the curvature of the curve (for example, the curvature and radius R and polarity of the curve) and the curve It consists of information relating to the depth (for example, the turning angle θ required for passing the curve, the length of the curve, etc.).

  The navigation device 16 detects the current position and the traveling direction of the host vehicle based on the current position information of both the current position information of the host vehicle input from the GPS receiver, and stores the road information storage unit 15 based on the detection result. Map matching is performed on the stored road information to control the display position of the current position of the own vehicle on the display screen, and the operator is detected via the detected current position of the own vehicle or various switches and keyboards. The display of the map on the display screen is controlled with respect to the appropriate vehicle position input by.

  The communication unit 17 is configured to be able to receive travel information of other vehicles. For example, the communication unit 17 is configured to be able to communicate with the service center 32 via the base station 31, and is configured to be able to communicate with other vehicles by inter-vehicle communication. The service center 32 collects vehicle travel information. The communication unit 17 transmits the travel information of the host vehicle to the other vehicle 41 and the base station 31, receives the travel information of the other vehicle 41 transmitted from the other vehicle 41 and the base station 31, and drives the received travel information. It outputs to plan generation ECU18.

  The operation plan generation ECU 18 includes a CPU, a ROM, a RAM, a nonvolatile memory, an A / D converter, a D / A converter, a port, and the like, and associates the calculated estimated road surface μ with the corresponding position information. The road surface μ map 18a is stored. The driving plan generation ECU 18 determines the road surface μ of the target road based on the traveling information of other vehicles having a traveling record received by the communication unit 17 and the traveling information of the own vehicle having the traveling record detected by the own vehicle traveling information input 14. Based on the estimated road surface μ, the tire generation force (= road surface μ x contact load) is calculated, and a driving plan (including speed and steering angle) is generated on condition that the calculated tire generation force is not exceeded. Output to the vehicle operation control ECU 19.

  The vehicle motion control ECU 19 is connected to vehicle motion devices such as an EPS (electric power steering) 20, an ECB (brake device) 21, and an engine device 22, and controls the operation of actuators of these vehicle motion devices. In the planned operation mode, the vehicle motion control ECU 19 controls the actuator of the vehicle motion device based on the operation plan input from the operation plan generation ECU 18.

  For example, the engine device 22 includes a throttle actuator that opens and closes a throttle valve in the electronic throttle device and adjusts the throttle opening, and the vehicle operation control ECU 19 operates the throttle actuator in response to the engine control signal, and the throttle valve Adjust the opening. In addition, for example, the ECB (brake device) 21 includes a brake actuator that adjusts the control hydraulic pressure to the wheel cylinder, and the vehicle operation control ECU 19 outputs a brake control signal to operate the brake actuator to brake the wheel cylinder. Adjust hydraulic pressure. Further, for example, the EPS (electric power steering) 20 includes a steering actuator that applies a rotational driving force by the motor as a steering torque to the steering mechanism via the speed reduction mechanism, and the vehicle operation control ECU 19 outputs a steering control signal. Then, the steering actuator is operated and the steering torque is adjusted by the motor.

  Next, the operation plan generation process of the operation plan generation ECU 18 will be described in detail with reference to FIGS. When creating a driving plan for a vehicle, the road surface μ is necessary. However, there is no method for reliably estimating the road surface μ, and conventionally, the limit road surface μ or the high road surface μ (for example, “1”) is fixed and used for vehicle control. The method of fixing to the limit road surface μ is not practical because the detection frequency is very low on general roads. Further, the method of fixing to the high road surface μ has a safety problem.

Therefore, in the present embodiment, the driving plan generation ECU 18 determines the road surface μ based on the front and rear Gx and the lateral Gy detected on the road surface in actual traveling of the own vehicle or another vehicle, that is, the front and rear Gx and the lateral Gy that have a track record of traveling. = (Gx ² + Gy ² ) ^1/2 , tire generation force is calculated based on the estimated road surface μ, and a safe driving plan (speed, steering angle is provided on condition that the calculated tire generation force is not exceeded) Generated). The vehicle operation control ECU 19 controls the operation of the vehicle according to the operation plan generated by the operation plan generation ECU 18.

  The driving plan is composed of a number of parameters necessary for traveling of the vehicle, such as position, speed pattern, acceleration pattern, steering angle pattern, yaw angle, and yaw rate. When such an operation plan is generated, a predetermined section of the road may be set as a block unit, and a travel locus in each block may be generated in units of meshes that are sections obtained by dividing the travel path. Further, when generating an operation plan, an evaluation function may be used.

2 and 3 are diagrams for explaining the relationship among the lateral Gy, the front and rear Gx, and the estimated road surface μ. FIG. 3 shows a road such as that shown in FIG. 2 where the sections A to B of the straight line are accelerated, the sections B to C of the curve are steadily turned, the section C of the straight line travels at a steady speed, and the section D of the straight line is obtained. Is a diagram showing an example of measured values of lateral Gx and front and rear Gy when decelerating and a road surface μ = (front and rear Gx ² + lateral Gy ² ) ^1/2 estimated based on the measured lateral Gx and front and rear Gy It is. Here, (front and rear Gx ² + lateral Gy ² ) ^1/2 is not an accurate road surface μ, but only guarantees a lower limit of the road surface μ. However, in the case of autonomous driving, road surface μ = (front and rear Gx Safe driving is possible by using ² + lateral Gy ² ) ^1/2 .

  As a method of collecting travel information with a track record (front and rear Gx, lateral Gy, and position information thereof), for example, a method of acquiring travel information from another vehicle (for example, a preceding vehicle) 41 by inter-vehicle communication, travel There are a method of collecting traveling information of the own vehicle on a high-frequency road, a method of collecting traveling information of other vehicles 41 from the service center 32 for a target road section, and the like.

FIG. 4 is a flowchart for explaining an operation in which the operation plan generation ECU 18 of FIG. 1 collects travel information. In FIG. 4, first, the operation plan generation ECU 18 collects travel information (front and rear Gx, lateral Gy, position information, etc.) having a travel record from the own vehicle or another vehicle for each point on the target road (step S1). ), The estimated road surface μ = (Gx ² + Gy ² ) ^1/2 is calculated based on the collected front and rear Gx and lateral Gy (step S2), and the positional information is associated with the calculated estimated road surface μ to obtain the road surface μ Registration in the map 18a (step S3).

  FIG. 5 is a flowchart for explaining the operation of creating a travel locus of the operation plan generation ECU 18. In the figure, the operation plan generation ECU 18 determines whether or not the operation mode is the planned operation mode (step S11). If the operation mode is not the planned operation mode (“No” in step S11), the road surface μ = 1 is set. (Step S15), output to the vehicle motion control ECU 19. The vehicle motion control ECU 19 controls actuators such as an EPS (electric power steering device) 20, an ECB (brake device) 21, and an engine device 22 under the condition of road surface μ = 1 (step S16).

  On the other hand, when in the planned operation mode (“Yes” in step S11), the operation plan generation ECU 18 reads the estimated road surface μ from the road surface μ map 18a for each point of the target road, and reads the estimated road surface μ that has been read out. Tire generating force is calculated based on (Step S12).

  The driving plan generation ECU 18 reads the road information (road shape such as curvature) of the target driving route from the road information storage unit 15, and based on the read road information and the tire generation force, the driving plan (speed and steering angle) of each point. Etc.) (step S13) and output to the vehicle motion control ECU 19. That is, the speed and steering angle at each point on the target travel route are calculated on condition that the tire generation force is not exceeded.

  The vehicle motion control ECU 19 controls actuators such as an EPS (electric power steering device) 20, an ECB (brake device) 21, and an engine device 22 based on the operation plan generated by the operation plan generation ECU 18 (step S14).

  In the above-described method, the vehicle is driven under a condition lower than the actual road surface μ. However, since the other vehicle or the own vehicle actually uses only the road surface μ, it is based on the proven road surface μ. There is no problem even if the operation plan is generated. In addition, regarding the problem when the road surface μ is estimated to be lower than the actual value, the road surface μ may be updated to the up side in a predetermined step, and the amount of the up is dependent on the ability of the driving control system that supports the vehicle. Can be determined.

  As described above, according to the vehicle control apparatus of the first embodiment, the operation plan generation ECU 18 includes travel information with a track record of traveling of the host vehicle or other vehicles (including front and rear Gx, lateral Gy, position information, and the like). The road surface μ of the road subject to the driving plan is estimated based on the front and rear Gx and the lateral Gy that have a running record, the tire generating force is calculated based on the estimated road surface μ, and the calculated tire generating force is Since it was decided to generate an operation plan under conditions that do not exceed, it is possible to use the road surface μ actually experienced by the own vehicle or other vehicles, and generate a safe operation plan using travel information with travel results It becomes possible to do. In addition, it is particularly useful for ensuring safety when autonomous driving is performed.

In addition, since the estimated road surface μ = (front and rear Gx ² + lateral Gy ² ) ^1/2 , it is possible to calculate the proven road surface μ with a simple calculation.

(Embodiment 2)
In the second embodiment, the reliability of the road surface μ is calculated based on the degree of nonlinearity between the vehicle and the tire, and when the reliability of the calculated estimated road surface μ is low, the estimated road surface μ is corrected. FIG. 6 is a block diagram illustrating an example of a schematic configuration of the vehicle control device according to the second embodiment. 6, parts having the same functions as those in FIG. 1 are denoted by the same reference numerals, description of common parts is omitted, and only different points will be described.

  In FIG. 6, the driving plan generation ECU 18 includes a μ reliability map 18b for calculating the reliability of the estimated road surface μ. FIG. 7 is a diagram for explaining an example of the μ reliability map 18b. In the figure, the vertical axis represents the reliability of the estimated road surface μ, and the horizontal axis represents the actual yaw rate value γ−the standard yaw rate γ *. Here, the standard yaw rate γ * is a suitable yaw rate determined by the actually measured vehicle speed and steering angle. The measured value γ of the yaw rate—the reference yaw rate γ * indicates the degree of nonlinearity (yaw rate deviation) between the vehicle and the tire. The reliability of the estimated road surface μ is constant when the measured yaw rate γ−standard yaw rate γ * is 0 to T1, linearly increases when T1 to T2, and is constant when T2 is greater than T2.

  Based on the actually measured yaw rate γ, vehicle speed, and steering angle, the driving plan generation ECU 18 calculates the actual yaw rate value γ-standard yaw rate γ *, and then refers to the μ reliability map 18b to calculate the calculated yaw rate. The reliability of the road surface μ corresponding to the actually measured value γ−the standard yaw rate γ * is calculated.

  FIG. 8 is a diagram for explaining a method of correcting the estimated road surface μ. In the figure, the horizontal axis indicates a point, the vertical axis indicates an example of the estimated road surface μ and the reliability of the estimated road surface μ, A is the estimated road surface μ, B is the reliability of the estimated road surface μ, and C Indicates the corrected estimated road surface μ. When the reliability of the estimated road surface μ is equal to or less than the threshold value n, the operation plan generation ECU 18 corrects the estimated road surface μ because the reliability of the estimated road surface μ is not high. The estimation of the estimated road surface μ is performed by, for example, interpolating the estimated road surface μ where the reliability of the estimated road surface μ is less than or equal to the threshold value n by Hermite interpolation or the like using the road surface μ whose reliability is higher than the threshold value n. Can do.

  FIG. 9 is a flowchart for explaining the operation of the operation plan generation ECU 18 for creating an operation plan. In the figure, the same step numbers are assigned to steps that perform the same processing as in FIG. 5, and only different points will be described.

  In FIG. 9, in step S21, the driving plan generation ECU 18 refers to the μ reliability map 18b and calculates the reliability of the estimated road surface μ based on the actually measured yaw rate, vehicle speed, and steering angle (step S21). . Next, the operation plan generation ECU 18 determines whether or not the reliability of the estimated road surface μ is equal to or less than the threshold value n (step S22), and when the reliability of the estimated road surface μ is equal to or less than the threshold value n (in step S22). “Yes”), the estimated road surface μ is corrected (step S23). As described above, when the reliability of the estimated road surface μ is equal to or less than the threshold value n, the corrected estimated road surface μ is stored in the road surface μ map 18a. On the other hand, if the reliability of the estimated road surface μ is not less than or equal to the threshold value n in Step 22 (“No” in Step S22), the process proceeds to Step S3.

  As described above, according to the second embodiment, the driving plan generation ECU 18 calculates the reliability of the estimated road surface μ based on the degree of nonlinearity between the vehicle and the tire, and the calculated reliability of the estimated road surface μ is equal to or less than a predetermined value. Therefore, it is possible to calculate a highly reliable road surface μ.

  In the above-described embodiment, the case where the driving plan is generated based on the estimated road surface μ has been described. However, the vehicle control may be performed based on the estimated road surface μ. Further, in the above-described embodiment, the reliability of the estimated road surface μ is calculated from the criterion of the non-linear degree (yaw rate deviation) of the vehicle and the tire, but may be calculated from the reference of the wheel slip ratio. Good. A two-dimensional (road traveling direction and road width direction) road surface μ map may be generated as the road surface μ map 18a.

  As described above, the vehicle control device and the vehicle control method according to the present invention are useful when generating a highly safe driving plan.

DESCRIPTION OF SYMBOLS 1 Vehicle control apparatus 11 Camera apparatus 12 Radar apparatus 14 Own vehicle travel information input part 15 Road information storage part 16 Car navigation apparatus 17 Communication part (other vehicle travel information input part)
18 Operation plan generation ECU
18a Road surface μ map 18b μ reliability map 19 Vehicle motion control ECU
20 EPS (Electric power steering)
21 ECB (Electronic Brake Device)
22 Engine device 31 Base station 32 Service center 41 Other vehicle

Claims (7)

Traveling information input means for inputting traveling information with a traveling record of the own vehicle or another vehicle;
Based on the travel information input by the travel information input means, an operation plan generating means for generating an operation plan;
A vehicle control device comprising: The travel information includes front and rear Gx, lateral Gy, and position information,
The operation plan generating means estimates a road surface friction coefficient (hereinafter referred to as “friction coefficient” μ) of a target road based on the front and rear Gx and lateral Gy, and generates tires based on the estimated road surface μ. The vehicle control apparatus according to claim 1, wherein the driving plan is generated under a condition that the force is calculated and the calculated tire generation force is not exceeded. 3. The vehicle control device according to claim 1, wherein the operation plan generation unit estimates (front and rear Gx ² + lateral Gy ² ) ^1/2 as a road surface μ.   The driving plan generation means calculates the reliability of the road surface μ based on the degree of nonlinearity between the vehicle and the tire, and corrects the road surface μ where the calculated reliability of the road surface μ is not more than a predetermined value. The vehicle control device according to any one of claims 3 to 4.   5. The vehicle control device according to claim 1, wherein the driving plan includes a vehicle speed and a steering angle.   The vehicle control apparatus according to claim 1, wherein the travel plan generation unit generates an operation plan using an evaluation function. A travel information input process for inputting travel information with a track record of own vehicle or other vehicle;
An operation plan generation step for generating an operation plan based on the travel information input in the travel information input step;
The vehicle control method characterized by including.

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