JP6787270B2 - Vehicle travel control device - Google Patents

Description

The present invention relates to a vehicle traveling control device that controls a vehicle speed (that is, a vehicle speed) when traveling on a curved road (hereinafter, simply referred to as a "curve").

Conventionally, a vehicle travel control device (hereinafter, referred to as a "conventional device") that detects a curve in front of the vehicle and accelerates or decelerates the vehicle according to the detected curve has been proposed (for example, Patent Document 1). See).

JP-A-2010-149700

The conventional device searches for road information in front of the vehicle using a navigation device mounted on the vehicle, and calculates the radius of curvature (turning radius) of the curve in front of the vehicle based on the road information. Then, the conventional device executes deceleration control for decelerating the vehicle based on the calculated turning radius. However, the conventional device may be referred to as, for example, a positioning error of the navigation device, an inadequate map information, an abnormality in communication with the navigation device, etc. (hereinafter, these are collectively referred to as a "fault of the navigation device". .) Is not designed in case it occurs.

For example, in a branch road divided into a straight road and a curve, even though the vehicle is traveling on one curve of the branch road, the navigation device causes the vehicle to move to the other straight line of the branch road due to the above positioning error. It may be determined that the vehicle is traveling on the road. In this case, since the conventional device receives the information on the straight road from the navigation device, the deceleration control of the vehicle is not performed.

Further, in a situation where a curve exists in front of the vehicle, the conventional device may not be able to acquire road information in front of the vehicle from the navigation device due to an abnormality in communication with the navigation device. However, since the conventional device does not perform appropriate processing when the road information in front of the vehicle cannot be acquired, it is not possible to control the deceleration of the vehicle until the vehicle reaches the curve in front of the vehicle.

The present invention has been made to solve the above problems. That is, one of the objects of the present invention is to drive a vehicle in which the vehicle speed can be appropriately controlled until the vehicle reaches a curve ahead or while the vehicle is traveling on a curve when a malfunction occurs in the navigation device. It is to provide a control device.

The vehicle travel control device of the present invention (hereinafter, may be referred to as "the device of the present invention") is
Constant speed control that causes the own vehicle to travel at a constant speed according to the target speed, and the following inter-vehicle distance that causes the own vehicle to follow the preceding vehicle while maintaining the distance between the own vehicle and the preceding vehicle at a predetermined distance. A vehicle control means (206) that executes at least one of the controls, and
Information acquisition means (201) for receiving road information regarding the position of the own vehicle and the road in front of the own vehicle from the navigation devices (20, 21, 22, 23) mounted on the own vehicle.
Detection means (15, 18) for detecting running state information (SPD, YRa) representing the current running state of the own vehicle, and
By the time the own vehicle reaches the predetermined section so that the lateral acceleration of the own vehicle becomes equal to or less than the predetermined allowable lateral acceleration when the own vehicle travels on the predetermined section of the road in front of the own vehicle. A first target acceleration calculation means (202) that calculates a first target acceleration (G1), which is a target value of acceleration for decelerating a vehicle, based on the road information and the traveling state information.
A radius of curvature estimating means (203) that estimates the radius of curvature (R2) of the road on which the own vehicle is currently traveling based on the traveling state information, and
The second target acceleration (G2), which is the target value of the acceleration for decelerating the own vehicle so that the lateral acceleration of the own vehicle becomes equal to or less than the allowable lateral acceleration after a predetermined time, is set to the estimated radius of curvature and the radius of curvature. A second target acceleration calculation means (204) calculated based on the running state information, and
When the information acquisition means can normally acquire the road information from the navigation device, it is determined that the current device state is the normal state (402), and the information acquisition means obtains the road information from the navigation device. The state determining means (207) for determining that the current device state is the fail state (403) when the acquisition is not normally performed, and
The target acceleration selection means (205) for determining the set target acceleration (Gf) according to the current device state determined by the state determination means, and
With
The vehicle control means
When the constant speed control is executed, the constant speed control acceleration (CC control target acceleration), which is a target value of acceleration for accelerating or decelerating the own vehicle so that the speed of the own vehicle matches the target speed. Gtgt) was determined as the third target acceleration (510),
When the following vehicle-to-vehicle distance control is executed, the following vehicle-to-vehicle distance, which is a target value of acceleration for accelerating or decelerating the own vehicle so that the inter-vehicle distance between the own vehicle and the preceding vehicle is maintained at the predetermined distance. The distance control acceleration (ACC control target acceleration Gtgt) is determined as the third target acceleration (510).
The target acceleration selection means is
When the current device state is the normal state, the smaller of the first target acceleration and the second target acceleration is determined as the set target acceleration (550).
When the current device state is the fail state, the second target acceleration is determined as the set target acceleration (555).
The vehicle control means
When the set target acceleration is smaller than the third target acceleration, the speed of the own vehicle is controlled by controlling the acceleration of the own vehicle so that the actual acceleration of the own vehicle matches the set target acceleration. (560: Yes, 565),
When the third target acceleration is equal to or less than the set target acceleration, the speed of the own vehicle is controlled by controlling the acceleration of the own vehicle so that the actual acceleration of the own vehicle matches the third target acceleration. (560: No, 570).

The device of the present invention can control the vehicle speed until the own vehicle reaches a curve ahead or while the own vehicle is traveling on the curve when a malfunction of the navigation device occurs. For example, on a branch road that is divided into a straight road and a curve, the information acquisition means erroneously obtains information on the straight road due to a positioning error of the navigation device even though the own vehicle is actually traveling on the curve. Suppose you received it. In this case, the first target acceleration calculated based on the information on the straight road is larger than the second target acceleration calculated based on the radius of curvature of the curve currently running. At this time, the target acceleration selection means selects the smaller second target acceleration as the set target acceleration. When the second target acceleration is smaller than the third target acceleration (acceleration for constant speed control or acceleration for tracking inter-vehicle distance control), the vehicle control means can decelerate the vehicle using the second target acceleration. Therefore, even if the information acquisition means receives erroneous road information, the vehicle control means can perform deceleration control using the second target acceleration calculated based on the radius of curvature of the curve currently traveling.

Further, when the information acquisition means cannot normally acquire the road information from the navigation device, that is, when the current device state is the fail state, the target acceleration selection means determines the second target acceleration as the set target acceleration. Therefore, even when the current device state is the fail state, if the second target acceleration is smaller than the third target acceleration (acceleration for constant speed control or acceleration for tracking inter-vehicle distance control), the vehicle control means The vehicle can be decelerated using the second target acceleration calculated based on the radius of curvature of the curve currently running.

In the above description, in order to help the understanding of the present invention, the names and / or symbols used in the embodiments are added in parentheses to the configurations of the invention corresponding to the embodiments described later. However, each component of the present invention is not limited to the embodiment defined by the reference numerals.

It is a schematic block diagram of the vehicle travel control device which concerns on embodiment of this invention. It is a functional block diagram of the operation support ECU shown in FIG. It is a top view which showed the radius of curvature of a vehicle and a curve. It is a state transition diagram of the system state which concerns on embodiment of this invention. It is a flowchart for demonstrating the operation of the driving support ECU shown in FIG.

Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

As shown in FIG. 1, the vehicle travel control device (hereinafter, may be referred to as “the present embodiment”) according to the embodiment of the present invention is a vehicle (hereinafter, for distinguishing from other vehicles). It is applied to (may be referred to as "own vehicle"), and includes a driving support ECU 10, a navigation ECU 20, an engine ECU 30, and a brake ECU 40.

These ECUs are electric control units (Electric Control Units) including a microcomputer as a main part, and are connected to each other so as to be able to transmit and receive information via a CAN (Controller Area Network) (not shown). In the present specification, the microcomputer includes a CPU 101, a ROM 102, a RAM 103, an interface (I / F) 104, and the like. The CPU 101 realizes various functions by executing instructions (programs, routines) stored in the ROM 102.

The driving support ECU 10 is connected to the sensors (including switches) listed below, and receives detection signals or output signals of those sensors. Each sensor may be connected to an ECU other than the driving support ECU 10. In that case, the driving support ECU 10 receives the detection signal or output signal of the sensor from the ECU to which the sensor is connected via CAN.

The accelerator pedal operation amount sensor 11 detects the operation amount (accelerator opening degree) of the accelerator pedal 11a of the own vehicle, and outputs a signal representing the accelerator pedal operation amount AP.
The brake pedal operation amount sensor 12 detects the operation amount of the brake pedal 12a of the own vehicle and outputs a signal indicating the brake pedal operation amount BP.

The steering angle sensor 13 detects the steering angle of the own vehicle and outputs a signal representing the actual steering angle θ.
The steering torque sensor 14 detects the steering torque applied to the steering shaft US of the own vehicle by operating the steering handle SW, and outputs a signal representing the actual steering torque Tra.
The vehicle speed sensor 15 detects the traveling speed (vehicle speed) of the own vehicle and outputs a signal indicating the vehicle speed SPD.

The surrounding sensor 16 acquires information on at least the road in front of the own vehicle and the three-dimensional object existing on the road. The three-dimensional object represents, for example, a moving object such as a pedestrian, a bicycle and an automobile, and a fixed object such as a utility pole, a tree and a guardrail. Hereinafter, these three-dimensional objects may be referred to as "targets". Further, the surrounding sensor 16 calculates the presence / absence of the target and the relative relationship between the own vehicle and the target (that is, the distance between the own vehicle and the target, the relative speed between the own vehicle and the target, and the like). It is designed to output.

The surrounding sensor 16 includes, for example, a radar sensor and a camera sensor.

For example, the radar sensor radiates radio waves in the millimeter wave band (hereinafter referred to as "millimeter wave") to the peripheral area of the own vehicle including at least the front area of the own vehicle, and by a target existing within the radiation range. Receives reflected millimeter waves (ie, reflected waves).

More specifically, the radar sensor includes a millimeter wave transmission / reception unit and a processing unit. The processing unit determines the phase difference between the millimeter wave transmitted from the millimeter wave transmitter / receiver and the reflected wave received by the millimeter wave transmitter / receiver, the attenuation level of the reflected wave, and the time from the transmission of the millimeter wave to the reception of the reflected wave. For each detected target (n), the inter-vehicle distance (longitudinal distance) Dfx (n), the relative speed Vfx (n), the lateral distance Dfy (n), the relative lateral speed Vfy (n), and the like are predetermined. Obtained every time the passage of time.

The inter-vehicle distance Dfx (n) is the distance between the own vehicle and the target (n) (for example, the preceding vehicle) along the central axis of the own vehicle.
The relative speed Vfx (n) is the difference (= Vs−Vj) between the speed Vs of the target (n) (for example, the preceding vehicle) and the speed Vj of the own vehicle. The speed Vs of the target (n) is the speed of the target (n) in the traveling direction of the own vehicle.
The lateral distance Dfy (n) is the distance from the central position of the target (n) (for example, the center position of the width of the preceding vehicle) in the direction orthogonal to the central axis of the own vehicle. The lateral distance Dfy (n) is also referred to as the "lateral position".
The relative lateral velocity Vfy (n) is the velocity of the center position of the target (n) (for example, the center position of the width of the preceding vehicle) in the direction orthogonal to the center axis of the own vehicle.

The camera sensor includes a stereo camera and an image processing unit. The stereo camera captures the landscape of the left side region and the right side region in front of the vehicle and acquires a pair of left and right image data. The image processing unit calculates and outputs the presence / absence of a target and the relative relationship between the own vehicle and the target based on a pair of left and right image data taken by the stereo camera. In this case, the driving support ECU 10 combines the relative relationship between the own vehicle and the target obtained by the radar sensor and the relative relationship between the own vehicle and the target obtained by the camera sensor, thereby causing the own vehicle. Determine the relative relationship between and the target. Further, the camera sensor recognizes lane markers such as white lines on the left and right of the road (hereinafter, simply referred to as "white lines") based on the pair of left and right image data captured, and recognizes the shape of the road (for example, simply referred to as "white line"). , Radius of curvature), and the positional relationship between the road and the vehicle are calculated and output.

The information acquired by the surrounding sensor 16 is called target information. The surrounding sensor 16 repeatedly transmits the target information to the driving support ECU 10 every time a predetermined time elapses. The ambient sensor 16 does not necessarily have to include both a radar sensor and a camera sensor, and may include, for example, only the radar sensor or only the camera sensor.

The operation switch 17 is a switch operated by the driver. By operating the operation switch 17, the driver can select whether or not to execute the follow-up vehicle-to-vehicle distance control (ACC: adaptive cruise control).

The yaw rate sensor 18 detects the yaw rate of the own vehicle and outputs the actual yaw rate YRa.

Hereinafter, information representing the current running state of the vehicle, such as vehicle speed SPD, actual yaw rate YRa, actual steering angle θ, and actual steering torque Tra, may be referred to as “driving state information”.

The driving support ECU 10 can execute the following inter-vehicle distance control (ACC). Further, the driving support ECU 10 can execute speed adjustment support control (hereinafter, may be referred to as "speed management control"). The speed adjustment support control is a traveling control that controls the speed of the own vehicle based on the radius of curvature of the curve in front of the own vehicle. As will be described later, the driving support ECU 10 includes a target acceleration for ACC control (including a target acceleration for constant speed control described later, and is conveniently referred to as a “third target acceleration” during a period in which the own vehicle travels on a road including a curved section. ) And the target acceleration for speed adjustment support control are selected. The driving support ECU 10 controls the vehicle speed of the own vehicle by adjusting the acceleration of the own vehicle so that the acceleration of the own vehicle matches the selected target acceleration.

The vehicle is equipped with a navigation device. The navigation device includes a navigation ECU 20. The navigation ECU 20 is adapted to guide the route of the own vehicle based on the position of the own vehicle and the map information. Therefore, the navigation ECU 20 is connected to a GPS receiver 21 that receives a GPS signal for detecting the position of its own vehicle, a map database 22 that stores map information, and a touch panel display 23 that is a human-machine interface. Has been done. The navigation ECU 20 identifies the current position (current position) Pnow of the own vehicle based on the GPS signal, and performs various arithmetic processes based on the position Pnow of the own vehicle and the map information stored in the map database 22. Is performed, and the route guidance is performed using the display 23.

The map information stored in the map database 22 includes road information. Road information includes road parameters for each section of the road. For example, on the road information, the width of the road, the slope, the one-sided slope (Kant), the radius of curvature (or the curvature), and the like are associated with each section of the road. The radius of curvature of the road is, for example, the radius of curvature of the curve drawn by the center line connecting the centers in the width direction of the road (see FIG. 3). The curvature is the reciprocal of the radius of curvature.

The engine ECU 30 is connected to the engine actuator 31. The engine actuator 31 includes a gasoline fuel injection, a spark ignition type, and a throttle valve actuator that changes the opening degree of the throttle valve of the internal combustion engine 32. The engine ECU 30 can change the torque generated by the internal combustion engine 32 by driving the engine actuator 31. The torque generated by the internal combustion engine 32 is transmitted to drive wheels (not shown) via a transmission (not shown). Therefore, the engine ECU 30 can control the driving force of the own vehicle and change the acceleration state (acceleration) by controlling the engine actuator 31.

The brake ECU 40 is connected to the brake actuator 41. The brake actuator 41 is provided in a hydraulic circuit between a master cylinder (not shown) that pressurizes hydraulic oil by the pedaling force of the brake pedal 12a and a friction brake mechanism 42 provided on the left, right, front, and rear wheels. The brake actuator 41 adjusts the hydraulic pressure supplied to the wheel cylinder built in the brake caliper 42b of the friction brake mechanism 42 in response to an instruction from the brake ECU 40. When the wheel cylinder is operated by the oil pressure, the brake pad is pressed against the brake disc 42a and a friction braking force is generated. Therefore, the brake ECU 40 can control the braking force of the own vehicle and change the acceleration state (deceleration, that is, negative acceleration) by controlling the brake actuator 41.

Next, the operation of the present implementation device configured as described above will be described. As described above, the driving support ECU 10 executes the following inter-vehicle distance control and the speed adjustment support control. First, these controls will be described.

(Following inter-vehicle distance control)
The following inter-vehicle distance control (ACC) is a driving support control in which an inter-vehicle distance control function is added to a constant speed control (cruise control: referred to as CC). The constant speed control (CC) is a control for driving the own vehicle at a constant speed according to a target vehicle speed without requiring the driver to operate the accelerator pedal. The inter-vehicle distance control function is a function of following the own vehicle to the preceding vehicle while maintaining the inter-vehicle distance between the preceding vehicle and the own vehicle traveling in front of the own vehicle at a predetermined distance. The following vehicle-to-vehicle distance control itself is well known (see, for example, Japanese Patent Application Laid-Open No. 2014-148293, Japanese Patent Application Laid-Open No. 2006-315491, Japanese Patent No. 4172434, Japanese Patent No. 4929777, etc.). Therefore, it will be briefly described below.

The driving support ECU 10 executes the following inter-vehicle distance control when the following inter-vehicle distance control is required by the operation of the operation switch 17.

More specifically, when the driving support ECU 10 is required to control the distance between following vehicles, the driving support ECU 10 selects a vehicle to be followed based on the target information acquired by the surrounding sensor 16. For example, in the driving support ECU 10, the relative position of the target (n) specified from the detected lateral distance Dfy (n) of the target (n) and the inter-vehicle distance Dfx (n) becomes longer as the inter-vehicle distance becomes longer. It is determined whether or not the vehicle exists in a predetermined tracking target vehicle area so that the size of the vehicle becomes smaller. Then, when the relative position of the target exists in the tracking target vehicle area for a predetermined time or longer, the driving support ECU 10 selects the target (n) as the tracking target vehicle (a). When there are a plurality of vehicles to be tracked, the driving support ECU 10 selects the vehicle having the smallest inter-vehicle distance Dfx (n) as the vehicle to be tracked.

Further, the driving support ECU 10 calculates the target acceleration Gtgt according to any of the following equations (1) and (2). The target acceleration Gtgt calculated according to any of the equations (1) and (2) is also referred to as "target acceleration Gtgt for tracking inter-vehicle distance control (for ACC control)". In the equations (1) and (2), Vfx (a) is the relative speed of the vehicle (a) to be followed, and k1 and k2 are predetermined positive gains (coefficients). ΔD1 is an inter-vehicle deviation (= Dfx (a) −Dtgt) obtained by subtracting the target inter-vehicle distance Dtgt from the inter-vehicle distance Dfx (a) of the tracking target vehicle (a). The target inter-vehicle distance Dtgt is calculated by multiplying the target inter-vehicle time Ttgt set by the driver using the operation switch 17 by the vehicle speed SPD of the own vehicle (that is, Dtgt = Ttgt · SPD).

When the value (k1, ΔD1 + k2, Vfx (a)) is positive or “0”, the driving support ECU 10 determines the target acceleration Gtgt using the following equation (1). ka1 is a positive gain (coefficient) for acceleration, and is set to a value of "1" or less.
When the value (k1, ΔD1 + k2, Vfx (a)) is negative, the driving support ECU 10 determines the target acceleration Gtgt using the following equation (2). kd1 is a deceleration gain (coefficient) and is set to "1" in this example.
Gtgt (for acceleration) = ka1 · (k1 · ΔD1 + k2 · Vfx (a)) ... (1)
Gtgt (for deceleration) = kd1 · (k1 · ΔD1 + k2 · Vfx (a)) ... (2)

When there is no target in the tracking target vehicle area, the driving support ECU 10 executes constant speed control (CC). That is, the driving support ECU 10 determines the target acceleration Gtgt based on the target vehicle speed and the vehicle speed SPD so that the vehicle speed SPD of the own vehicle matches the target vehicle speed set by the operation of the operation switch 17. The driving support ECU 10 sets the target acceleration Gtgt to "0" if the target vehicle speed matches the vehicle speed SPD. When the target vehicle speed is higher than the vehicle speed SPD, the driving support ECU 10 gradually increases the target acceleration Gtgt. When the target vehicle speed is lower than the vehicle speed SPD, the driving support ECU 10 gradually reduces the target acceleration Gtgt. The target acceleration Gtgt calculated in this way is also referred to as "constant speed control (CC control) target acceleration Gtgt".

The driving support ECU 10 uses the engine ECU 30 to control the engine actuator 31 so that the acceleration of the vehicle matches the target acceleration Gtgt, and also controls the brake actuator 41 using the brake ECU 40 as needed.

(Speed adjustment support control)
Next, the speed adjustment support control will be described. As shown in FIG. 2, the driving support ECU 10 includes a road information acquisition unit 201, a first target acceleration calculation unit 202, and a radius of curvature estimation unit 203 as functional components for executing speed adjustment support control. A second target acceleration calculation unit 204, a target acceleration selection unit 205, a vehicle control unit 206, and a system state determination unit 207 are provided. These execute the processing (calculation) described below every time a predetermined time elapses.

The road information acquisition unit 201 acquires road information regarding the current position of the own vehicle and the road ahead of the current position of the own vehicle. Specifically, the road information acquisition unit 201 acquires the road information included in the position Pnow of the own vehicle and the map information of the map database 22 via the navigation ECU 20. For example, the road information includes information on various parameters of the section constituting the position Pnow of the own vehicle to a point 400 m ahead of the own vehicle. The road information acquisition unit 201 includes information on "radius of curvature R (for example, R1 in FIG. 3), one-sided gradient i (kant), and the position of the start point of the section" as various parameters of each of the above sections, and self. The vehicle position Pnow information is output to the first target acceleration calculation unit 202. The road information acquisition unit 201 outputs information on the one-sided gradient inow of the position Pnow of the own vehicle to the second target acceleration calculation unit 204.

The first target acceleration calculation unit 202 calculates the first target acceleration G1 in which the lateral acceleration of the own vehicle is suppressed to a predetermined allowable lateral acceleration (for example, 0.15 g) or less in all of the above sections. Specifically, in order to calculate the first target acceleration G1, the first target acceleration calculation unit 202 first calculates the target vehicle speed V1 according to the following equation (3) for each of the above sections.
Target vehicle speed V1 = {R × (Mg + g × i)} ^1/2 … (3)
R: Radius of curvature [m]
Mg: Allowable lateral acceleration [m / s ² ]
g: Gravity acceleration ≒ 9.8 [m / s ² ]
i: One-sided gradient [%]

The first target acceleration calculation unit 202 calculates the distance L from the position Pnow of the own vehicle to the position of each start point of the above-mentioned section. Further, the first target acceleration calculation unit 202 acquires the information of the current vehicle speed SPD from the vehicle speed sensor 15. The first target acceleration calculation unit 202 calculates the target acceleration for each of the above sections based on the target vehicle speed V1, the current vehicle speed SPD, and the distance L. The target acceleration is the acceleration (deceleration) required for the vehicle speed of the own vehicle at the time when the own vehicle reaches each start point of the above-mentioned section to match the target vehicle speed V1.

In the present specification, the acceleration includes acceleration during acceleration (acceleration with a positive value) and acceleration during deceleration (acceleration with a negative value). The first target acceleration calculation unit 202 determines the minimum acceleration from the target accelerations of each of the above sections as the first target acceleration G1. Therefore, the first target acceleration G1 is an acceleration at which the lateral acceleration of the own vehicle is suppressed to be equal to or less than the allowable lateral acceleration in all of the above sections. The first target acceleration calculation unit 202 outputs the first target acceleration G1 to the target acceleration selection unit 205.

The radius of curvature estimation unit 203 calculates the radius of curvature R2 (see FIG. 3) of the road on which the own vehicle is currently traveling. Specifically, the radius of curvature estimation unit 203 acquires the information of the current vehicle speed SPD from the vehicle speed sensor 15 and the information of the actual yaw rate YRa from the yaw rate sensor 18. The radius of curvature estimation unit 203 calculates the radius of curvature R2 according to the following equation (4) based on the current vehicle speed SPD and the actual yaw rate YRa.
Radius of curvature R2 = SPD / YRa ... (4)
The radius of curvature estimation unit 203 outputs the information of the radius of curvature R2 to the second target acceleration calculation unit 204.

The second target acceleration calculation unit 204 calculates the second target acceleration G2 in which the lateral acceleration of the own vehicle is suppressed to a predetermined allowable lateral acceleration (for example, 0.15 g) or less after a predetermined set time (for example, 1 second). .. Specifically, the second target acceleration calculation unit 204 substitutes the predetermined allowable lateral acceleration, the radius of curvature R2, and the one-sided gradient inow of the position Pnow of the own vehicle into the right side of the above equation (3) to obtain the target vehicle speed V2. Is calculated.

The second target acceleration calculation unit 204 is based on the vehicle speed SPD of the own vehicle, the target vehicle speed V2, and the predetermined set time, and the acceleration required for the vehicle speed of the own vehicle to match the target vehicle speed V2 after the predetermined set time ( Deceleration) is calculated as the second target acceleration G2. The second target acceleration calculation unit 204 outputs the second target acceleration G2 to the target acceleration selection unit 205.

As shown in FIG. 4, the system state determination unit 207 determines whether the system state is one of the control standby state 401, the normal state 402, and the fail state 403 after the power of the operation support ECU 10 is turned on. Is repeatedly determined as will be described later. The system state determination unit 207 outputs the determined information Sinfo (hereinafter, simply referred to as “system state information”) regarding the current system state to the target acceleration selection unit 205.

When the power of the operation support ECU 10 is turned on, the system state determination unit 207 determines that the system state is the control standby state 401. The control standby state 401 is a state immediately after the following vehicle-to-vehicle distance control is requested by the operation of the operation switch 17 (immediately after the system is turned on), and the road information in front of the own vehicle has not yet been acquired. When the system state determination unit 207 determines that the system state is in the control standby state 401, the system state determination unit 207 repeatedly determines whether or not a predetermined normal condition is satisfied every time a predetermined time elapses. For example, a predetermined normal condition is when the parameters of the road for a predetermined number of sections in front of the own vehicle (information including radius of curvature R, one-sided gradient i, and the position of the starting point of the section) can be normally acquired. To establish. When the road information acquisition unit 201 can normally acquire the road parameters for a predetermined number of sections in front of the own vehicle, the road information acquisition unit 201 indicates that the road parameters have been normally acquired Nsig (hereinafter, "normal signal"). ”) Is output to the system status determination unit 207. When the system state determination unit 207 receives the normal signal Nsig from the road information acquisition unit 201, it determines that the predetermined normal condition is satisfied, and determines that the system state has changed from the control standby state 401 to the normal state 402.

The normal state 402 is a state in which the parameters of the roads for the predetermined number of sections can be normally acquired. When the system state determination unit 207 determines that the system state is in the normal state 402, the system state determination unit 207 repeatedly determines whether or not the predetermined fail condition is satisfied every time the predetermined time elapses. For example, the predetermined fail condition is satisfied when at least one of (a) to (d) is satisfied.
(A) An abnormality has occurred in the navigation ECU 20.
(B) An abnormality has occurred in communication with the navigation ECU 20.
(C) The parameters of the road in front of the acquired vehicle contain or are missing outliers.
(D) The road parameters have changed compared to the previous acquisition.

Regarding the condition (a) above, the navigation ECU 20 monitors whether or not an abnormality has occurred in itself, and when any abnormality occurs, a signal indicating that the navigation device is in a fail state. Fsig (hereinafter referred to as "fail signal") is output to the system state determination unit 207.

Regarding the condition (b) above, the road information acquisition unit 201 measures the time from the start of communication with the navigation ECU 20 to the reception of the road parameter. When the road information acquisition unit 201 cannot receive the road parameter from the navigation ECU 20 for a predetermined abnormality determination time or longer, the road information acquisition unit 201 outputs a fail signal Fsig to the system state determination unit 207.

Regarding the condition (c) above, the road information acquisition unit 201 determines whether the road information received from the navigation ECU 20 includes predetermined parameters (radius of curvature R, one-sided gradient i, and the position of the start point of each section). To do. Further, when a predetermined parameter is included in the road information, the road information acquisition unit 201 determines whether or not each value of the parameter is within a predetermined normal range set for each type of parameter. The road information acquisition unit 201 outputs a fail signal Fsig to the system state determination unit 207 when the road information does not include a predetermined parameter or when the value of the parameter is out of the normal range.

Regarding the condition (d) above, the road information acquisition unit 201 records in the RAM 103 the parameters of the road information of the predetermined section acquired at the previous calculation timing (hereinafter, simply referred to as “previous parameters”). Then, the previous parameter and the parameter of the road information of the corresponding section acquired at the current calculation timing (hereinafter, simply referred to as "this time parameter") are compared. When the current parameter and the previous parameter are different, the navigation ECU 20 outputs a parameter of a road different from the road determined that the own vehicle is traveling at the previous calculation timing due to a positioning error in the navigation device. There is a possibility that Therefore, the road information acquisition unit 201 outputs the fail signal Fsig to the system state determination unit 207 when the current parameter and the previous parameter are different.

When the system state determination unit 207 receives the fail signal Fsig, it determines that the predetermined fail condition is satisfied, and determines that the system state has changed from the normal state 402 to the fail state 403.

The fail state 403 is a state in which the parameters of the roads for the predetermined number of sections have not been normally acquired. When the system state determination unit 207 determines that the system state is in the fail state 403, the system state determination unit 207 repeatedly determines whether or not the predetermined recovery condition is satisfied every time the predetermined time elapses. The predetermined recovery condition is satisfied when the parameters of the roads for the predetermined number of sections can be normally acquired. For example, the predetermined recovery condition is satisfied when the communication abnormality between the road information acquisition unit 201 and the navigation ECU 20 is resolved and the road information acquisition unit 201 can normally acquire the parameters of the road in front of the own vehicle. When the road information acquisition unit 201 can normally acquire the parameters of the roads for a predetermined number of sections in front of the own vehicle, the road information acquisition unit 201 outputs a normal signal Nsig to the system state determination unit 207. When the system state determination unit 207 receives the normal signal Nsig, it determines that the predetermined recovery condition is satisfied, and determines that the system state has changed from the fail state 403 to the normal state 402.

Further, in the fail state 403, the system state determination unit 207 repeatedly determines whether or not the predetermined standby condition is satisfied every time the predetermined time elapses. For example, the predetermined standby condition is satisfied when the following equation (5) is satisfied. The second target acceleration calculation unit 204 records the second target acceleration G2 in the RAM 103 every time the second target acceleration G2 is calculated. The target acceleration calculation unit 206a records the target acceleration Gtgt in the RAM 103 every time the target acceleration Gtgt is calculated. The system state determination unit 207 determines whether the second target acceleration G2 and the target acceleration Gtgt recorded in the RAM 103, that is, the latest second target acceleration G2 and the target acceleration Gtgt satisfy the following equation (5). When the following equation (5) is satisfied, the system state determination unit 207 determines that the system state has changed from the fail state 403 to the control standby state 401.
Target acceleration Gtgt <Second target acceleration G2 ... (5)

The above-mentioned standby condition is a condition for determining whether to continue using the second target acceleration G2 as the set target acceleration Gf for speed adjustment support control in the fail state 403. As will be described later with reference to FIG. 5, in the present embodiment, when the current system state is the fail state 403, the target acceleration selection unit 205 determines the second target acceleration G2 as the set target acceleration Gf. In the fail state 403, if the target acceleration Gtgt for ACC is smaller than the second target acceleration G2, the vehicle speed may be controlled by ACC without performing speed adjustment support control. Therefore, when the predetermined standby condition is satisfied, the system state determination unit 207 shifts the system state from the fail state 403 to the control standby state 401 so that the target acceleration Gtgt for ACC is selected.

The target acceleration selection unit 205 acquires the system state information Sinfo from the system state determination unit 207. The target acceleration selection unit 205 determines the set target acceleration Gf for speed adjustment support control according to the current system state as described later. The target acceleration selection unit 205 outputs the determined set target acceleration Gf to the vehicle control unit 206.

The vehicle control unit 206 selects and executes either the following inter-vehicle distance control (ACC) or the speed adjustment support control. Specifically, the vehicle control unit 206 includes a target acceleration calculation unit 206a. When the target acceleration calculation unit 206a is required to control the distance between the following vehicles, the target acceleration Gtgt for ACC control according to any one of the above equations (1) and (2) when the following vehicle (a) is present. Is calculated every time a predetermined time elapses. The target acceleration calculation unit 206a calculates the CC control target acceleration Gtgt for matching the vehicle speed SPD with the target vehicle speed when the following vehicle-to-vehicle distance control is required and the following vehicle (a) does not exist. .. Hereinafter, the target acceleration Gtgt for ACC control and the target acceleration Gtgt for CC control are also referred to as "target acceleration Gtgt for ACC / CC control (third target acceleration)".

Further, the vehicle control unit 206 compares the target acceleration Gtgt for ACC / CC control with the set target acceleration Gf for speed adjustment support control. When the set target acceleration Gf is smaller than the target acceleration Gtgt for ACC / CC control, the vehicle control unit 206 selects the set target acceleration Gf as the final target acceleration Ge. On the other hand, when the target acceleration Gtgt for ACC / CC control is equal to or less than the set target acceleration Gf, the vehicle control unit 206 selects the target acceleration Gtgt as the final target acceleration Ge. The vehicle control unit 206 calculates the amount of change in the vehicle speed SPD per unit time as the actual acceleration. The vehicle control unit 206 controls the engine actuator 31 using the engine ECU 30 so that the actual acceleration matches the final target acceleration Ge (that is, the selected target acceleration Gf or Gtgt), and if necessary. The brake actuator 41 is controlled by using the brake ECU 40.

(Specific control)
Next, the specific operation of the driving support ECU 10 will be described with reference to FIG. The CPU 101 of the driving support ECU 10 (hereinafter, simply referred to as “CPU”) executes the “travel control routine” shown by the flowchart of FIG. 5 every time a predetermined time elapses. Further, the CPU identifies the system state as described above by executing a routine (not shown).

Therefore, at a predetermined timing, the CPU starts the process from step 500 in FIG. 5 and proceeds to step 505 to determine whether or not the ACC execution condition is satisfied. The ACC execution condition is a condition that is satisfied when both the conditions 1 and 2 described below are satisfied.
(Condition 1) Follow-up inter-vehicle distance control is required by operating the operation switch 17.
(Condition 2) The vehicle speed SPD is equal to or higher than the low side vehicle speed threshold value SPD1 and lower than the high side vehicle speed threshold value SPD2.

If the ACC execution condition is not satisfied, the CPU determines "No" in step 505, proceeds to step 595, and temporarily ends this routine. On the other hand, when the ACC execution condition is satisfied, the CPU determines "Yes" in step 505, performs the processes of steps 510 to 530 described below in order, and proceeds to step 540.

Step 510: The CPU calculates the target acceleration Gtgt for ACC / CC control as described above. This step corresponds to the target acceleration calculation unit 206a of the vehicle control unit 206.

Step 515: The CPU uses the navigation ECU 20 to provide road information (radius of curvature R, one-sided gradient i, and a start point of each section) corresponding to the current position Pnow of the own vehicle and a predetermined number of sections in front of the own vehicle. Position) is obtained. This step corresponds to the road information acquisition unit 201.

Step 520: As described above, the CPU has a first target in which the lateral acceleration of its own vehicle is suppressed to "predetermined allowable lateral acceleration (for example, 0.15 g)" or less in all of the above-mentioned predetermined number of sections. Calculate the acceleration G1. This step corresponds to the first target acceleration calculation unit 202.

Step 525: As described above, the CPU estimates the radius of curvature R2 of the road on which the own vehicle is currently traveling based on the current vehicle speed SPD and the actual yaw rate YRa. This step corresponds to the radius of curvature estimation unit 203.

Step 530: As described above, the CPU has a second target acceleration in which the lateral acceleration of the own vehicle is suppressed to "predetermined allowable lateral acceleration (for example, 0.15 g)" or less after a predetermined set time (for example, 1 second). Calculate G2. This step corresponds to the second target acceleration calculation unit 204.

After executing the process of step 530, the CPU proceeds to step 540 and acquires the current system state that has been separately determined (specified). The CPU determines whether the current system state is the control standby state 401, the normal state 402, or the fail state 403.

When the current system state is the control standby state 401, the CPU proceeds from step 540 to step 545 and sets a predetermined fixed value (for example, 5 m / s ² ) to the set target acceleration Gf for convenience. The control standby state 401 is a state in which the road information in front of the own vehicle has not yet been acquired. Therefore, in such a state, it is desirable to control the vehicle speed by using the target acceleration Gtgt for ACC / CC control. Therefore, the above-mentioned predetermined fixed value is sufficiently larger than the value at which the determination of "No" is always obtained in step 560 described later, that is, the maximum value of the value that the target acceleration Gtgt for ACC / CC control can take. It is set to a large value.

On the other hand, when the current system state is the normal state 402, the CPU proceeds from step 540 to step 550, and the smaller of the first target acceleration G1 and the second target acceleration G2 is set as the set target acceleration for speed adjustment support control. Determined as Gf.

On the other hand, when the current system state is the fail state 403, the CPU proceeds from step 540 to step 555 and determines the second target acceleration G2 as the set target acceleration Gf. The fail state 403 means that the CPU cannot acquire the correct first target acceleration G1 because the navigation device is in trouble. Therefore, the CPU determines the second target acceleration G2 as it is as the set target acceleration Gf without comparing the first target acceleration G1 and the second target acceleration G2.

The CPU proceeds to step 560 after executing any of the processes of step 545, step 550, and step 555. Steps 540 to 555 correspond to the target acceleration selection unit 205.

Next, the CPU proceeds to step 560 and determines whether or not the "set target acceleration Gf for speed adjustment support control" is smaller than the "target acceleration Gtgt for ACC / CC control".

When the set target acceleration Gf is smaller than the target acceleration Gtgt, the CPU determines "Yes" in step 560 and proceeds to step 565 to control the vehicle speed of the own vehicle using the set target acceleration Gf (that is, speed adjustment). Assist control) is executed. That is, the CPU controls the engine actuator 31 and the brake actuator 41 so that the actual acceleration of the own vehicle matches the "set target acceleration Gf as the final target acceleration Ge". After that, the CPU proceeds to step 595 and temporarily ends this routine.

On the other hand, when the set target acceleration Gf is equal to or higher than the target acceleration Gtgt, the CPU determines "No" in step 560 and proceeds to step 570 to control the vehicle speed of the own vehicle using the target acceleration Gtgt (that is,). , Tracking inter-vehicle distance control including constant speed control) is executed. That is, the CPU controls the engine actuator 31 and the brake actuator 41 so that the actual acceleration of the own vehicle matches the "target acceleration Gtgt as the final target acceleration Ge". After that, the CPU proceeds to step 595 and temporarily ends this routine. In addition, step 560 to step 570 correspond to the vehicle control unit 206.

As described above, the present implementation device can control the vehicle speed until the vehicle reaches a curve in front or while the vehicle is traveling on the curve when a malfunction occurs in the navigation device. For example, even if the current system state is the normal state 402, that is, even if the executing device can normally acquire the road information from the navigation device, the implementing device may acquire the incorrect road information as follows. is there. For example, in a branch road divided into a straight road and a curve, the navigation device may erroneously output information on the straight road due to a positioning error even though the own vehicle is actually traveling on the curve. is there. In such a case, since the first target acceleration G1 is calculated based on the information of the straight road, the first target acceleration G1 is the second target acceleration calculated based on the radius of curvature R2 of the curve currently running. It will be larger than G2. When the current system state is the normal state 402, the executing device selects the smaller second target acceleration G2 of the first target acceleration G1 and the second target acceleration G2 as the set target acceleration Gf. When the second target acceleration G2 is smaller than the target acceleration Gtgt for ACC / CC control, the present implementation device can decelerate the vehicle using the second target acceleration G2. Therefore, even if the present implementation device receives information on a road different from the road on which the vehicle is actually traveling, deceleration control is performed using the second target acceleration G2 calculated based on the radius of curvature R2 of the curve currently being traveled. It can be carried out.

On the other hand, when the parameters of the roads for a predetermined number of sections cannot be obtained from the navigation ECU 20, or when the parameters of the roads for a predetermined number of sections obtained are not accurate, that is, the current system state is the fail state 403. In this case, the present implementation device determines the second target acceleration G2 calculated based on the radius of curvature R2 of the currently traveling curve as the set target acceleration Gf. Therefore, even when the current system state is the fail state 403, when the second target acceleration G2 is smaller than the target acceleration Gtgt for ACC / CC control, the present implementation device uses the second target acceleration G2. The vehicle can be decelerated.

Further, when the current system state is the control standby state 401, the executing device preferentially selects the target acceleration Gtgt for ACC / CC control as the final target acceleration Ge. As a result, in the control standby state 401, the present implementation device can decelerate the vehicle by using the target acceleration Gtgt for ACC / CC control.

Further, when it is not necessary to perform the speed adjustment support control even after the current system state becomes the fail state 403 (that is, the target acceleration Gtgt is smaller than the second target acceleration G2, the above equation (5) is established. In the case), the present implementation device can prioritize the control of the vehicle speed by the ACC / CC by changing the state of the system from the fail state 403 to the control standby state 401. As a result, the vehicle behavior can be stabilized after the system state becomes the fail state 403.

Further, the present implementing device can select the follow-up inter-vehicle distance control according to the situation of the own vehicle even in the situation where the own vehicle is traveling on a curve. For example, the present implementation device compares the set target acceleration Gf for speed adjustment support control and the target acceleration Gtgt for ACC control, and when the target acceleration Gtgt is equal to or less than the set target acceleration Gf, the ACC control using the target acceleration Gtgt To execute. For example, it is assumed that the own vehicle catches up with the preceding vehicle while traveling on a curve, and the distance between the preceding vehicle and the preceding vehicle becomes smaller than a predetermined distance. In this case, a larger deceleration is required depending on the preceding vehicle factor, and it is desirable that the target acceleration Gtgt for ACC control is selected. In such a situation, since the target acceleration Gtgt for ACC control becomes smaller than the set target acceleration Gf for speed adjustment support control, the present implementer selects the target acceleration Gtgt as the final target acceleration. Therefore, when the preceding vehicle exists while the own vehicle is traveling on the curve, the safety can be improved by switching from the speed adjustment support control to the ACC control.

As another example, when the own vehicle is traveling near the exit of the curve, the value of the radius of curvature R2 gradually increases, and the second target acceleration G2 also gradually increases accordingly. However, if the distance between the vehicle and the preceding vehicle is small, it is necessary to suppress acceleration. In such a situation, since the target acceleration Gtgt for ACC control becomes smaller than the set target acceleration Gf for speed adjustment support control, the present implementer selects the target acceleration Gtgt as the final target acceleration. Therefore, when the own vehicle is traveling near the exit of the curve and the preceding vehicle is present, the present implementing device can improve the safety by switching from the speed adjustment support control to the ACC control.

The present invention is not limited to the above embodiment, and various modifications can be adopted within the scope of the present invention.

The method for calculating the radius of curvature R2 is not limited to the above example. For example, the value of the radius of curvature calculated based on the vehicle speed SPD and the actual yaw rate YRa may be corrected by the actual steering angle θ. Alternatively, the calculation method proposed in Japanese Patent Application Laid-Open No. 2004-217178 may be adopted.

In step 555 of FIG. 5, the CPU may set a lower limit value with respect to the second target acceleration G2. For example, the CPU may set the lower limit of the second target acceleration G2 to 0 m / s ² in step 555. That is, when the second target acceleration G2 becomes a negative value (acceleration for decelerating the own vehicle), the CPU sets the second target acceleration G2 set in the set target acceleration Gf to 0 m / s ^2. You may fix it. According to this configuration, the current vehicle speed can be maintained in step 565 when the target acceleration Gtgt for ACC / CC control is a positive value. As a result, even though the target acceleration Gtgt for ACC / CC control is a positive value (that is, the situation where the own vehicle may accelerate), the own vehicle does not accelerate, so something is wrong with the driver. It is possible to notify that the defect has occurred, that is, the fail state 403.

The above-mentioned normal condition, fail condition, recovery condition and standby condition are examples, and are not limited thereto. For example, the normal condition may include a condition as to whether or not information can be normally acquired from various sensors.

Each of the above-mentioned normal condition, fail condition, and recovery condition may include a condition of confidence in the position of the own vehicle. The degree of confidence is an index value indicating how reliable the section of the road on which the own vehicle travels is specified. By adding the degree of confidence to each of the above conditions, it is possible to determine whether the acquired road information is highly reliable. The navigation ECU 20 can calculate the estimation error of the position of the own vehicle based on the GPS signal, the map information, and the like by using a known method such as a Kalman filter, and can calculate the confidence level according to the estimation error. .. The navigation ECU 20 outputs the confidence level to the driving support ECU 10. For example, the normal condition may include a condition as to whether or not the confidence level is equal to or higher than a predetermined value. The fail condition may include a condition as to whether or not the self-confidence is less than a predetermined value. The recovery condition may include a condition as to whether or not the self-confidence level has recovered to a predetermined value or higher.

The vehicle travel control device according to the present embodiment is applied to a vehicle capable of executing constant speed control and follow-up inter-vehicle distance control, but is configured to be capable of executing only constant speed control, or follow-up. It may be applied to a vehicle configured so that only inter-vehicle distance control can be performed. When the vehicle travel control device according to the present embodiment is applied to a vehicle configured to be able to execute only constant speed control, the target acceleration calculation unit 206a calculates the target acceleration Gtgt for constant speed control. The vehicle control unit 206 selects and executes either constant speed control (CC) or speed adjustment support control. When the set target acceleration Gf is smaller than the target acceleration Gtgt calculated by the constant speed control, the vehicle control unit 206 performs deceleration control using the set target acceleration Gf. On the other hand, when the set target acceleration Gf is equal to or higher than the target acceleration Gtgt calculated by the constant speed control, the vehicle control unit 206 performs deceleration control using the target acceleration Gtgt.

10 ... Driving support ECU, 20 ... Navigation ECU, 30 ... Engine ECU, 40 ... Brake ECU, 201 ... Road information acquisition unit, 202 ... First target acceleration calculation unit, 203 ... Radius of curvature estimation unit, 204 ... Second target acceleration Calculation unit, 205 ... Target acceleration selection unit, 206 ... Vehicle control unit, 207 ... System state determination unit.

Claims (1)

Constant speed control that causes the own vehicle to run at a constant speed according to the target speed, and follow-up vehicle distance that causes the own vehicle to follow the preceding vehicle while maintaining the distance between the own vehicle and the preceding vehicle at a predetermined distance. A vehicle control means that executes at least one of the controls,
An information acquisition means for receiving road information regarding the position of the own vehicle and the road in front of the own vehicle from the navigation device mounted on the own vehicle.
A detection means for detecting the running state information indicating the current running state of the own vehicle, and
By the time the own vehicle reaches the predetermined section so that the lateral acceleration of the own vehicle becomes equal to or less than the predetermined allowable lateral acceleration when the own vehicle travels on the predetermined section of the road in front of the own vehicle. A first target acceleration calculation means for calculating a first target acceleration, which is a target value of acceleration for decelerating a vehicle, based on the road information and the traveling state information.
A radius of curvature estimating means for estimating the radius of curvature of the road on which the own vehicle is currently traveling based on the traveling state information,
The second target acceleration, which is the target value of the acceleration for decelerating the own vehicle so that the lateral acceleration of the own vehicle becomes equal to or less than the allowable lateral acceleration after a predetermined time, is set to the estimated radius of curvature and the running state. The second target acceleration calculation means calculated based on the information,
When the information acquisition means can normally acquire the road information from the navigation device, it is determined that the current device state is the normal state, and the information acquisition means normally acquires the road information from the navigation device. A state determining means for determining that the current device state is a fail state when the device is not completed, and
A target acceleration selection means for determining a set target acceleration according to the current device state determined by the state determination means, and
With
The vehicle control means
When the constant speed control is executed, the constant speed control acceleration, which is the target value of the acceleration for accelerating or decelerating the own vehicle so that the speed of the own vehicle matches the target speed, is set as the third target acceleration. Decide and
When the following vehicle-to-vehicle distance control is executed, the following vehicle-to-vehicle distance, which is a target value of acceleration for accelerating or decelerating the own vehicle so that the inter-vehicle distance between the own vehicle and the preceding vehicle is maintained at the predetermined distance. The acceleration for distance control is determined as the third target acceleration, and
The target acceleration selection means is
When the current device state is the normal state, the smaller of the first target acceleration and the second target acceleration is determined as the set target acceleration.
When the current device state is the fail state, the second target acceleration is determined as the set target acceleration.
The vehicle control means
When the set target acceleration is smaller than the third target acceleration, the speed of the own vehicle is controlled by controlling the acceleration of the own vehicle so that the actual acceleration of the own vehicle matches the set target acceleration. ,
When the third target acceleration is equal to or less than the set target acceleration, the speed of the own vehicle is controlled by controlling the acceleration of the own vehicle so that the actual acceleration of the own vehicle matches the third target acceleration. ,
Vehicle travel control device.

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