JP2017136897A - Vehicle travel control device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To accurately estimate an interrupted position at a point in time that an interrupting vehicle completes interruption between the own vehicle and a target vehicle being followed, in a vehicle travel control device that causes the own vehicle to travel following a target vehicle while a predetermined inter-vehicle distance is maintained with respect to the target vehicle traveling ahead of and followed by the own vehicle.SOLUTION: A value obtained by adding a value obtained by multiplying an amount of change in reference distance per unit time and an estimated time taken for an interrupting vehicle to complete the interruption from a current point in time, to a reference distance that is the inter-vehicle distance of the interrupting vehicle at the current point in time, is acquired as an estimated inflow position.SELECTED DRAWING: Figure 3

Description

  The present invention relates to a vehicle travel control device that causes a subject vehicle to follow and follow a subject vehicle so as to maintain a predetermined inter-vehicle distance with respect to the subject vehicle that travels ahead (immediately before) the subject vehicle.

  One of the vehicle driving control devices of this type that has been known in the past (hereinafter also referred to as “conventional device”) is the “automatic lane” by changing the lane from the adjacent lane to the lane in which the host vehicle is traveling (the own lane). The other vehicle that interrupts “between the vehicle and the vehicle to be followed” is detected as an interrupt predicted vehicle. In the conventional apparatus, “the inter-vehicle distance between the predicted vehicle and the host vehicle when the predicted vehicle completes the interrupt (hereinafter also referred to as“ the inter-vehicle distance after completion of the interrupt ”)” is the own vehicle of the predicted vehicle. Is obtained based on the relative speed (i.e., the relative vertical speed, in other words, the amount of change per unit time of the inter-vehicle distance).

  Further, in the conventional apparatus, when a plurality of predicted vehicles are detected, the distance between the vehicle and the vehicle having the smallest inter-vehicle distance after completion of the interruption (hereinafter also referred to as “approach predicted vehicle”) becomes the target inter-vehicle distance. Thus, the acceleration of the host vehicle is adjusted (see, for example, Patent Document 1).

Japanese Patent No. 4531366 (paragraph 0035 and paragraph 0036)

  However, during the lane change, the relative lateral speed of the predicted vehicle to the host vehicle changes with the passage of time. Specifically, the absolute value of the relative lateral speed of the predicted vehicle to be interrupted starts to increase from the starting point of the lane change and reaches “0” when the interrupt is completed after reaching the maximum value. Therefore, if the inter-vehicle distance after completion of interruption is predicted based on the relative lateral speed at a certain point in time, the estimated inter-vehicle distance after completion of interruption and the actual inter-vehicle distance after completion of interruption due to the subsequent change in relative lateral speed. An error occurs.

  By the way, when a plurality of vehicles are inserted in front of the own vehicle, if the error is large, there is a high possibility that a vehicle other than the correct approach predicted vehicle is erroneously determined as the approach predicted vehicle. The vehicle acceleration may not be adjusted properly.

  Accordingly, one of the objects of the present invention is to calculate the inter-vehicle distance after completion of the interruption with higher accuracy, and thus to identify the approaching predicted vehicle with higher accuracy even when there are a plurality of interruption vehicles. Thus, it is to provide a vehicle travel control device that can adjust the acceleration of the host vehicle more appropriately.

  In order to achieve the above object, a vehicle travel control device according to the present invention (hereinafter also referred to as “the device of the present invention”) includes a follow-up target vehicle specifying unit, an interrupt predicted vehicle detection unit, an inter-vehicle distance prediction unit after completion of an interrupt. , An approach prediction vehicle specifying means, a first calculation means, a second calculation means, an acceleration mediation means, and a travel control means.

  The tracking target vehicle specifying unit specifies a “following target vehicle” that travels ahead of the “own vehicle”. The interrupt predicted vehicle detection means detects an “interrupt predicted vehicle” that is expected to interrupt between the host vehicle and the tracking target vehicle (step 805).

  The inter-vehicle distance prediction means after completion of the interruption is a distance between the predicted anti-interrupt vehicle and the host vehicle at the time when the detected predicted interrupt vehicle completes the interruption. It is obtained by repetitive calculation every predetermined time until the predicted vehicle completes the interrupt.

  When there are a plurality of detected predicted vehicles at the same time, the predicted approaching vehicle specifying means designates a vehicle having the smallest inter-vehicle distance after completion of the acquired interrupted vehicle among the predicted predicted vehicles as “approaching predicted vehicle”. (Step 825). On the other hand, when only one (one) predicted predicted vehicle is present, the predicted approaching vehicle specifying unit specifies the predicted predicted vehicle as an “approach predicted vehicle” (step 825).

  The first calculation means obtains the acceleration of the host vehicle necessary for setting the inter-vehicle distance (Dyf) between the tracking target vehicle and the host vehicle as a predetermined first inter-vehicle distance as “first acceleration (A1)”. To do. The second calculation means obtains the acceleration of the host vehicle necessary for setting the inter-vehicle distance (Dyn) between the approaching predicted vehicle and the host vehicle as a predetermined second inter-vehicle distance as “second acceleration (A2)”. To do.

  The acceleration arbitration means selects a smaller one of the first acceleration and the second acceleration as a “target acceleration” (steps 530, 535, and 545). The travel control means controls the driving force and braking force of the host vehicle so that the actual acceleration of the host vehicle approaches the target acceleration (step 540).

  Further, the inter-vehicle distance prediction means after completion of interruption includes lateral distance acquisition means, expected time acquisition means, and inter-vehicle distance calculation means after interruption completion.

  The lateral distance acquisition means acquires the “lateral distance (Dx)” at the present time of the predicted vehicle to be interrupted with respect to the host vehicle by measurement. The predicted time acquisition means divides the lateral distance by the “virtual lateral relative speed (Kvx)” of the predicted interrupted vehicle with respect to the host vehicle, so that the predicted predicted interrupt vehicle completes the interrupt from the present time. The “expected time (Tcutin)” is acquired.

  The after-interrupt completion inter-vehicle distance calculating means adds a change amount (Vx) per unit time of the reference distance and the expected time to a reference distance (Dy) that is a current inter-vehicle distance between the predicted vehicle and the own vehicle. The distance obtained by adding the product is calculated as the inter-vehicle distance (Day) after completion of the interruption.

  The amount of change per unit time of the reference distance represents the relative vertical speed of the vehicle predicted to be interrupted. By multiplying the predicted longitudinal time by the relative vertical speed of the predicted vehicle to be interrupted, the amount of change in the inter-vehicle distance (inter-vehicle distance change amount) from the present time to the completion of the interrupt can be obtained. By adding the inter-vehicle distance change amount to the reference distance, the inter-vehicle distance from the predicted vehicle at the time of completion of the interruption can be obtained.

  According to the device of the present invention, it is possible to accurately predict the expected inflow position even at the time immediately after the start of the interruption by the predicted vehicle. As a result, it is possible to appropriately adjust the acceleration of the vehicle according to the distance between the vehicle and the vehicle predicted to approach from the time immediately after the interruption by the specified vehicle predicted to approach until the time when the interrupt is completed, Occurrence of a situation where the vehicle occupant feels uncomfortable can be avoided.

  In the above description, in order to help understanding of the present invention, names and / or symbols used in the embodiment are attached to the configuration of the invention corresponding to the embodiment described later in parentheses. However, each component of the present invention is not limited to the embodiment defined by the reference numerals. Other objects, other features and attendant advantages of the present invention will be readily understood from the description of the embodiments of the present invention described with reference to the following drawings.

1 is a schematic diagram of a vehicle (present vehicle) to which a vehicle travel control device (present control device) according to an embodiment of the present invention is applied. It is a detailed block diagram of this control apparatus. It is a figure showing the example of the vehicle (other vehicle) which flows in between this vehicle and a tracking object vehicle. It is a graph showing the change with respect to time of relative lateral speed when other vehicles perform interruption. It is a flowchart showing the following travel control processing routine which this control device performs. It is a figure showing the example of the straight line area correction process which this control apparatus performs. It is a flowchart showing the 1st acceleration determination processing routine which this control apparatus performs. It is a flowchart showing the 2nd acceleration determination processing routine which this control apparatus performs. It is a flowchart showing the following travel control process routine which the vehicle travel control apparatus which concerns on the 2nd modification of embodiment of this invention performs.

  Hereinafter, a vehicle travel control device according to an embodiment of the present invention (hereinafter, also referred to as “the present control device”) will be described with reference to the drawings. This control apparatus is applied to the vehicle 10 shown in FIG. The vehicle 10 includes a driving support ECU 20, an engine ECU 50, and a brake ECU 60, which are electronic control units (ECUs).

  As shown in FIG. 2, the driving assistance ECU 20 includes a CPU 21, a ROM 22, and a RAM 23. The CPU 21 reads data, performs numerical calculations, outputs calculation results, and the like by sequentially executing a predetermined program (routine). The ROM 22 stores a program executed by the CPU 21, a lookup table (map), and the like. The RAM 23 temporarily stores data. Each of the engine ECU 50 and the brake ECU 60 includes a CPU, a ROM, and a RAM, like the driving support ECU 20.

  The driving support ECU 20, the engine ECU 50, and the brake ECU 60 are capable of data communication (data exchange is possible) via a communication / sensor system CAN (Controller Area Network) 70. More specifically, the driving assistance ECU 20 can perform data communication with the radar device 30, the ACC operation switch 41, the vehicle speed sensor 42, and the gyro sensor 43 via the CAN 70.

  The radar device 30 includes a front radar device 31, a right front radar device 32, a left front radar device 33, a right rear radar device 34, and a left rear radar device 35. The forward radar apparatus 31 includes a transmission unit, a reception unit, and a processing unit. As shown in FIG. 1, the front radar device 31 is disposed at the front end of the vehicle 10 and at the center in the vehicle width direction. The transmission unit has a central axis CS extending in a straight forward direction of the vehicle 10 and emits a radio wave with a predetermined angle θ1 from the central axis CS to the right and left directions (an electromagnetic wave having a frequency of 30 G to 300 GHz). ).

  In the following, the left-right direction of the vehicle 10 orthogonal to the central axis CS is defined as the x coordinate axis, and the central axis CS direction (that is, the front-rear direction of the vehicle 10) is defined as the y coordinate axis. The x coordinate is a positive value in the right direction of the vehicle 10 and a negative value in the left direction of the vehicle 10. On the other hand, the y coordinate has a positive value in the front direction of the vehicle 10 and a negative value in the rear direction of the vehicle 10. A center portion in the vehicle width direction at the front end portion of the vehicle 10 is an origin where x = 0 and y = 0.

  A part of the millimeter wave transmitted from the transmission unit of the forward radar device 31 is reflected by a target (for example, a vehicle other than the vehicle 10 (another vehicle)) and received by the reception unit of the front radar device 31. The processing unit of the forward radar apparatus 31 includes a phase difference between the millimeter wave transmitted by the transmission unit and the millimeter wave (reflected wave) received by the reception unit, the degree of attenuation of the reflected wave, and the reflected wave from the transmission of the millimeter wave. The distance between vehicles (vertical distance) Dy, relative vertical speed Vy, lateral distance Dx, relative lateral speed Vx, etc. for each detected target is acquired at each elapse of a predetermined time based on the time until the reception of.

  These pieces of information regarding the target are also collectively referred to as “target information”. The processing unit transmits the target information to the driving support ECU 20 via the CAN 70. If a plurality of targets are detected, the processing unit transmits target information corresponding to each of the targets to the driving support ECU 20.

  The right front radar device 32 is disposed in front of the vehicle 10 on the right side of the vehicle body as shown in FIG. The right front radar device 32 has the same configuration as the front radar device 31. The transmission unit of the right front radar device 32 has a central axis CFR extending obliquely right forward of the vehicle 10 and transmits a millimeter wave that propagates from the central axis CFR forward and backward with a predetermined angle θ2.

  The reception unit of the right front radar device 32 receives the millimeter wave reflected wave transmitted by the transmission unit of the right front radar device 32. The processing unit of the right front radar apparatus 32 acquires target information based on the transmitted millimeter wave and the received reflected wave. The processing unit of the right front radar device 32 transmits the acquired target information to the driving support ECU 20 via the CAN 70.

  The left front radar device 33 is disposed in front of the left side of the vehicle 10 as shown in FIG. The left front radar device 33 has the same configuration as the front radar device 31. The transmission unit of the left front radar device 33 has a center axis CFL extending obliquely left front of the vehicle 10 and transmits a millimeter wave propagating from the center axis CFL to the front and rear of the vehicle with a predetermined angle θ2.

  The reception unit of the left front radar device 33 receives the reflected millimeter wave transmitted by the transmission unit of the left front radar device 33. The processing unit of the left front radar device 33 acquires target information based on the transmitted millimeter wave and the received reflected wave. The processing unit of the left front radar device 33 transmits the acquired target information to the driving support ECU 20 via the CAN 70.

  As shown in FIG. 1, the right rear radar device 34 is disposed on the right rear side of the vehicle 10. The right rear radar device 34 has the same configuration as the front radar device 31. The transmission unit of the right rear radar device 34 has a central axis CRR extending diagonally right rear of the vehicle 10 and transmits millimeter waves propagating from the central axis CRR forward and rearward with a predetermined angle θ3.

  The reception unit of the right rear radar apparatus 34 receives the millimeter wave reflected wave transmitted by the transmission unit of the right rear radar apparatus 34. The processing unit of the right rear radar apparatus 34 acquires target information based on the transmitted millimeter wave and the received reflected wave. The processing unit of the right rear radar apparatus 34 transmits the acquired target information to the driving support ECU 20 via the CAN 70.

  The left rear radar device 35 is disposed on the left rear side of the vehicle 10 as shown in FIG. The left rear radar device 35 has the same configuration as the front radar device 31. The transmitter of the left rear radar device 35 has a central axis CRL extending obliquely left rear of the vehicle 10 and transmits millimeter waves propagating from the central axis CRL to the front and rear of the vehicle with a predetermined angle θ3.

  The reception unit of the left rear radar device 35 receives the reflected millimeter wave transmitted by the transmission unit of the left rear radar device 35. The processing unit of the left rear radar device 35 acquires target information based on the transmitted millimeter wave and the received reflected wave. The processing unit of the left rear radar device 35 transmits the acquired target information to the driving support ECU 20 via the CAN 70.

  As can be understood from FIG. 1, the detection region of the front radar device 31 and the detection region of the right front radar device 32 have portions that overlap each other (overlap region AR). Similarly, the detection region of the front radar device 31 and the detection region of the left front radar device 33 have a portion (overlap region AL) that overlaps each other. Therefore, the target in the overlap area AR is detected by both the front radar apparatus 31 and the right front radar apparatus 32, and the target in the overlap area AL is detected by both the front radar apparatus 31 and the left front radar apparatus 33. Is done.

  When the target (specifically, the part of the target that reflects the millimeter wave from the radar device) is ahead of the traveling direction of the vehicle 10 than the radar device that detects the target, The inter-vehicle distance Dy is a distance in the y-axis direction between the “front end of the vehicle 10” and the “rear end of the target”. On the other hand, when the target is behind the traveling direction of the vehicle 10 with respect to the radar device that detects the target, the inter-vehicle distance Dy is “the front end of the vehicle 10” and “the front end of the target”. ”In the y-axis direction.

  The relative longitudinal speed Vy is a change amount per unit time of the inter-vehicle distance Dy. The lateral distance Dx is a distance in the x-axis direction between the “center position in the vehicle width direction of the vehicle 10” and the “center position in the x-axis direction of the target (for example, the center position in the vehicle width direction of another vehicle)”. The relative lateral velocity Vx is a change amount per unit time of the lateral distance Dx.

  Referring again to FIG. 2, the ACC operation switch 41 is operated by the driver of the vehicle 10 in order to switch “following inter-vehicle distance control (ACC)” between the on state and the off state. The following inter-vehicle distance control is also simply referred to as “following traveling control”.

  The vehicle speed sensor 42 detects the vehicle speed Vs of the vehicle 10 and outputs a signal representing the vehicle speed Vs. The gyro sensor 43 is a three-axis angular velocity sensor, and outputs a signal representing the angular velocity of the vehicle 10 in the x-axis direction, the y-axis direction, and the z-axis direction orthogonal to the x-axis and the y-axis. That is, the gyro sensor 43 outputs a signal indicating the amount of change per unit time of the pitch angle, roll angle, and yaw angle.

  The engine ECU 50 is connected to a plurality of engine sensors 51 and receives detection signals from these sensors. The engine sensor 51 is a sensor that detects an operation state quantity of a “gasoline fuel injection type, spark ignition, internal combustion engine that is a driving source of the vehicle 10” (not shown). The engine sensor 51 includes an accelerator pedal operation amount sensor, a throttle valve opening sensor, an engine rotation speed sensor, an intake air amount sensor, and the like.

  Further, the engine ECU 50 is connected to an engine actuator 52 such as a throttle valve actuator and a fuel injection valve. The engine ECU 50 changes the torque Tq generated by the internal combustion engine by driving the engine actuator 52, thereby adjusting the driving force of the vehicle 10 to control the acceleration As (the amount of change in the vehicle speed Vs per unit time). It is supposed to be.

  The brake ECU 60 is connected to a plurality of brake sensors 61 and receives detection signals from these sensors. The brake sensor 61 is a sensor that detects a parameter used when controlling a “braking device (hydraulic friction braking device) mounted on the vehicle 10” (not shown). The brake sensor 61 includes a brake pedal operation amount sensor, a wheel speed sensor that detects the rotational speed of each wheel, and the like.

  Further, the brake ECU 60 is connected to a brake actuator 62. The brake actuator 62 is a hydraulic control actuator. The brake actuator 62 is disposed in a hydraulic circuit (all not shown) between a master cylinder that pressurizes hydraulic oil by the depression force of the brake pedal and a friction brake device including a well-known wheel cylinder provided on each wheel. Is done. The brake actuator 62 adjusts the hydraulic pressure supplied to the wheel cylinder. The brake ECU 60 drives the brake actuator 62 to generate a braking force (friction braking force) Bf on each wheel and adjust the acceleration As of the vehicle 10 (in this case, negative acceleration, that is, deceleration). It has become.

(Follow-up running control)
When the driver of the vehicle 10 switches the ACC operation switch 41 from the off state to the on state, the driving support ECU 20 starts the follow-up running control. When the follow-up running control is started, the driving support ECU 20 stores the vehicle speed Vs at that time in the RAM 23 as the set vehicle speed Vset. The driving assistance ECU 20 sets the target acceleration Atgt of the vehicle 10 so that the vehicle speed Vs coincides with the set vehicle speed Vset when there is no other vehicle (that is, a vehicle to be followed) traveling in front of the vehicle 10.

  Furthermore, the driving assistance ECU 20 requests the engine ECU 50 and the brake ECU 60 so that the actual acceleration As becomes equal to the target acceleration Atgt. In general, when the target acceleration Atgt is a positive value, the driving assistance ECU 20 requests the engine ECU 50 to increase the torque Tq. When the target acceleration Atgt is a negative value, the driving assistance ECU 20 requests the engine ECU 50 to decrease the torque Tq. If the target acceleration Atgt is a negative value and the absolute value thereof is relatively large, the driving assistance ECU 20 requests the brake ECU 60 to generate the braking force Bf.

  On the other hand, when there is a tracking target vehicle, the driving assistance ECU 20 sets the first acceleration A1 so that the following inter-vehicle distance Dyf, which is the inter-vehicle distance Dy with the tracking target vehicle, becomes the predetermined first inter-vehicle distance Dyt1. Furthermore, the driving assistance ECU 20 sets the target acceleration Atgt described above to a smaller value of the first acceleration A1 and the second acceleration A2 described later.

  The tracking target vehicle is a vehicle that travels ahead of the vehicle 10 in the lane (own lane) in which the vehicle 10 is traveling and is closest to the vehicle 10 among other vehicles. When the following inter-vehicle distance Dyf becomes larger than the predetermined following limit distance Dyth, the driving assistance ECU 20 determines that there is no following vehicle to be followed. The follow-up limit distance Dyth is longer than the first inter-vehicle distance Dyt1 (that is, Dyth> Dyt1).

  When the ACC operation switch 41 is switched from the on state to the off state by the driver of the vehicle 10 or when the brake pedal is operated by the driver, the driving support ECU 20 ends the follow-up traveling control.

(Interrupt vehicle prediction process)
During the execution of the follow-up running control, the driving assistance ECU 20 executes “interrupt vehicle prediction process”. More specifically, the driving assistance ECU 20 flows in a target (another vehicle) that is detected by the radar device 30 and travels in a lane (other lane) different from the own lane and may flow into the own lane. Extracted as an expected vehicle.

  Further, the driving support ECU 20 calculates an inter-vehicle distance after completion of inflow (inter-vehicle distance after completion of interruption) Day, which is a distance between the predicted inflow vehicle and the vehicle 10 at the time when the predicted inflow vehicle has completed inflow. If there are a plurality of predicted inflow vehicles, the driving support ECU 20 calculates the inter-vehicle distance Day after completion of the inflow for each of the predicted inflow vehicles.

  If the inter-vehicle distance Day after the inflow is a positive value and smaller than the following inter-vehicle distance Dyf (that is, if 0 <Day <Dyf), the expected inflow vehicle is between the vehicle 10 and the vehicle to be followed. It is expected to make an inflow "interrupt". A vehicle that is predicted to be interrupted is also referred to as an “interrupt predicted vehicle” for convenience. Among vehicles predicted to be interrupted, a vehicle having the smallest inter-vehicle distance Day after completion of inflow is also referred to as an “approach predicted vehicle” for convenience.

  The driving assistance ECU 20 sets the second acceleration A2 so that the predicted approach distance Dyn, which is the inter-vehicle distance Dy with the predicted approach vehicle, becomes the predetermined second inter-vehicle distance Dyt2. The second inter-vehicle distance Dyt2 is smaller than the first inter-vehicle distance Dyt1 (that is, Dyt2 <Dyt1).

  A method for calculating the inter-vehicle distance Day after completion of inflow will be described with reference to the examples of FIGS. FIG. 3A shows a vehicle 81 that flows into the own lane from the left lane of the own lane as an expected inflow vehicle. The vehicle 81 starts lane change at time t0 shown as the vehicle position 81a in FIG. 3A, and passes through time ta1 to time ta5 shown as the vehicle position 81b to the vehicle position 81f. Lane change (inflow) is completed at time ta6 indicated as position 81g. The inter-vehicle distance from the vehicle position 81g is the distance Dy1.

  An arrow (speed vector) V1 shown in FIG. 3A represents a relative speed vector of the vehicle 81 (that is, the vehicle position 81a) at time ta1. The length of the x-axis component V1x of the velocity vector V1 represents the absolute value of the relative lateral velocity Vx of the vehicle 81, and the length of the y-axis component V1y of the velocity vector V1 represents the absolute value of the relative longitudinal velocity Vy of the vehicle 81. Yes.

  If the expected inflow position of the vehicle 81 is predicted based on the speed vector V1 at time ta1, the vehicle position 81p at the intersection of the extension line of the speed vector V1 and the central axis CS is acquired. The inter-vehicle distance (that is, the predicted inter-vehicle distance) from the vehicle position 81p is the distance Dp1. On the other hand, since the actual inflow position of the vehicle 81 is the vehicle position 81g, the predicted inter-vehicle distance includes an error represented by (distance Dy1-distance Dp1).

  Similarly, FIG. 3B shows a vehicle 82 that flows into the own lane from the right lane of the own lane as an expected inflow vehicle. The vehicle 82 starts to change lanes at time t0 shown as the vehicle position 82a in FIG. 3B, and passes through time tb1 to time tb5 shown as the vehicle position 82b to the vehicle position 82f. Lane change (inflow) is completed at time tb6 shown as position 82g. The inter-vehicle distance from the vehicle position 82g is the distance Dy2.

  An arrow (speed vector) V2 shown in FIG. 3B represents a relative speed vector of the vehicle 82 (that is, the vehicle position 82a) at time tb1. As with the vehicle 81, when the inflow position of the vehicle 82 is predicted based on the speed vector V2 at the time tb1, the vehicle position 82p at the intersection of the extension line of the speed vector V2 and the central axis CS is acquired. . The inter-vehicle distance (that is, the predicted inter-vehicle distance) from the vehicle position 82p is the distance Dp2. On the other hand, since the actual inflow position of the vehicle 82 is the vehicle position 82g, the expected inter-vehicle distance includes an error represented by (distance Dp2-distance Dy2).

  The reason why an error occurs in the predicted inter-vehicle distance (distance Dp1 and distance Dp2) predicted based on the speed vector will be described. A change in the relative lateral speed Vx of the vehicle 81 from time t0 to time ta6 is shown by a curve Lc1 in FIG. As understood from the curve Lc1, the relative lateral velocity Vx of the vehicle 81 starts to increase from “0” at time t0, reaches the maximum value Vax3 at time ta3, and then returns to “0” at time ta6. ing. The relative lateral speed Vx at time ta1 is the speed Vax1.

  Similarly, a change in the relative lateral speed Vx of the vehicle 82 from time t0 to time tb6 is shown by a curve Lc2 in FIG. As understood from the curve Lc2, the relative lateral velocity Vx of the vehicle 82 starts to increase from “0” at time t0, reaches the maximum value Vbx3 at time tb3, and then returns to “0” at time tb6. ing. The relative lateral velocity Vx at time tb1 is the velocity Vbx1.

  The vehicle position 81p acquired at the time ta1 described above has an average value of the relative lateral speed Vx in the period until the inflow of the vehicle 81 into the own lane (that is, the period from the time ta1 to the time ta6) is the speed. This is an expected inflow position based on the assumption that it is Vax1. However, the average value of the relative lateral speed Vx of the vehicle 81 is the speed Vaxave shown in FIG. 4 and is larger than the speed Vax1 (that is, Vaxave> speed Vax1). Therefore, there is a divergence between the expected inter-vehicle distance (distance Dp1) and the actual inflow position (distance Dy1).

  Similarly, the vehicle position 82p acquired at time tb1 has an average value of the relative lateral speed Vx in a period until the inflow of the vehicle 81 into the own lane (that is, a period from time tb1 to time tb6) is This is an expected inflow position based on the assumption that the speed is Vbx1. However, the average value of the relative lateral speed Vx of the vehicle 82 is the speed Vbxave shown in FIG. 4 and is larger than the speed Vbx1 (that is, Vbxave> speed Vbx1). Therefore, there is a divergence between the expected inter-vehicle distance (distance Dp2) and the actual inflow position (distance Dy2).

  Therefore, when the interrupting vehicle prediction process is executed, the driving assistance ECU 20 determines that the average value of the relative lateral speed Vx until the inflow of the predicted inflow vehicle into the own lane is completed is a predetermined inflow average lateral speed Kvx (virtual lateral direction relative Speed). The inflow average lateral speed Kvx is a value in the vicinity of an average value of a plurality of “average value Vxave of relative lateral speed Vx when another vehicle actually interrupts”. In this example, the inflow average lateral velocity Kvx is 1 m / sec.

  A specific method for calculating the inter-vehicle distance Day after completion of inflow by the driving assistance ECU 20 will be described. The inter-vehicle distance Day after completion of the inflow is the longitudinal movement distance that is the amount of change in the inter-vehicle distance Dy during the elapse of the time required to complete the inflow (inflow completion time Tcutin) to the inter-vehicle distance Dy with the current inflow prediction vehicle. It is calculated by adding “ΔDy” (ie, Day = Dy + ΔDy). “The inter-vehicle distance Dy from the current predicted inflow vehicle” is also referred to as a “reference distance” for convenience.

  The longitudinal movement distance ΔDy is calculated by multiplying the inflow completion time Tcutin by the current relative longitudinal speed Vy of the expected inflow vehicle (that is, ΔDy = Tcutin × Vy). The inflow completion time Tcutin is calculated by dividing the absolute value of the lateral distance Dx of the predicted inflow vehicle at the present time by the inflow average lateral speed Kvx (that is, Tcutin = | Dx | / Kvx).

(Specific operation-follow-up running control process)
Next, a specific operation of the driving support ECU 20 will be described. The CPU 21 (hereinafter also simply referred to as “CPU”) of the driving assistance ECU 20 executes the “following travel control processing routine” shown by the flowchart in FIG. To run. Therefore, when the appropriate timing is reached, the CPU starts the process from step 500 in FIG. 5, sequentially performs the processes from step 505 to step 525 described below, and proceeds to step 530.

  Step 505: The CPU obtains information on the target detected by the radar device 30 (that is, the front radar device 31, the right front radar device 32, the left front radar device 33, the right rear radar device 34, and the left rear radar device 35). get. If one radar apparatus detects a plurality of targets, the CPU acquires information on the plurality of targets from the radar apparatus.

  Step 510: The CPU collects target information corresponding to targets (overlap targets) that are within the overlap area AR and detected by both the front radar device 31 and the right front radar device 32. That is, the CPU aggregates the two target information generated by each of these two radar devices into a single target information. If there are a plurality of duplicate targets, the CPU aggregates each piece of target information corresponding to the duplicate targets. Similarly, the CPU collects target information corresponding to targets that are in the overlap area AL and detected by both the front radar device 31 and the left front radar device 33.

  Step 515: The CPU determines, based on the signal from the gyro sensor 43, whether the section in which the vehicle 10 is traveling (traveling section) is a straight section or a curved section, and the traveling section is a straight section. If not (that is, if it is a curved section), straight section correction is performed according to the radius of curvature of the curved section. By the straight section correction, the CPU corrects each target information acquired from the radar device 30 to target information when the traveling section is assumed to be a straight section.

  This will be specifically described with reference to the example of FIG. In FIG. 6, the vehicle 10 is traveling in a curved section curved to the right. In FIG. 6, a tracking target vehicle 83 and an interrupt predicted vehicle 84 are shown. The positions of these vehicles when it is assumed that the tracking target vehicle 83 and the predicted interrupt vehicle 84 traveled in the straight section are shown as a corrected vehicle position 83m and a corrected vehicle position 84m.

  The following inter-vehicle distance Dyf of the tracking target vehicle 83 acquired by the radar device 30 is a distance Dy3. On the other hand, the distance from the current position of the vehicle 10 to the current position of the tracking target vehicle 83 estimated based on the radius of curvature of the traveling section of the vehicle 10 (the traveling trace of the tracking target vehicle 83 indicated by the broken line Ld) is a distance Dway. is there. Therefore, the CPU sets the corrected inter-vehicle distance Dmy3 of the tracking target vehicle 83 as the distance Dway (not the distance Dy3).

  Similarly, the CPU performs linear section correction for the lateral distance Dx, the relative longitudinal speed Vy, and the relative lateral speed Vx. By the straight section correction, the CPU converts (estimates) the distance Dx3 that is the lateral distance Dx of the tracking target vehicle 83 detected by the radar device 30 to the corrected lateral distance Dmx3 (in this example, substantially “0”). .

  The relative vertical velocity Vy and the relative lateral velocity Vx detected by the radar device 30 are indicated as a velocity vector V3. That is, the x-axis component of the velocity vector V3 represents the relative lateral velocity Vx, and the y-axis component represents the relative longitudinal velocity Vy. The corrected velocity vector is a zero vector. That is, the corrected relative vertical velocity Vmy3 and the corrected relative lateral velocity Vmx3 are both substantially “0”.

  Similarly, straight section correction is performed on the target information related to the predicted vehicle 84. Specifically, the inter-vehicle distance Dy of the predicted predicted vehicle 84 acquired by the radar apparatus 30 is the distance Dy4, and the lateral distance Dx is the distance Dx4. In addition, the relative vertical speed Vy and the relative lateral speed Vx of the interrupt predicted vehicle 84 are represented by the speed vector V4. The target information is converted into a corrected inter-vehicle distance Dmy4, a corrected lateral distance Dmx4, and a corrected speed vector Vm4, respectively, by straight line correction. In order to avoid complicated notation, hereinafter, “after correction” attached to each piece of target information that has been subjected to straight section correction will be omitted, and the name and code before correction will be described.

  Step 520: The CPU executes the “first acceleration determination processing routine” shown in FIG. 7 in order to set the first acceleration A1 so that the following inter-vehicle distance Dyf becomes the first inter-vehicle distance Dyt1. This routine will be described in detail later.

  Step 525: The CPU executes the “second acceleration determination processing routine” shown in FIG. 8 in order to set the second acceleration A2 so that the inter-vehicle distance Dy to the approaching predicted vehicle becomes the second inter-vehicle distance Dyt2. . This routine will be described in detail later.

  Step 530: The CPU determines whether or not the first acceleration A1 is smaller than the second acceleration A2. If the first acceleration A1 is smaller than the second acceleration A2, the CPU makes a “Yes” determination at step 530 to proceed to step 535, and sets the target acceleration Atgt to a value equal to the first acceleration A1.

  Next, the CPU proceeds to step 540 and controls the engine actuator 52 and the brake actuator 62 via the engine ECU 50 and the brake ECU 60 so that the actual acceleration As becomes the target acceleration Atgt. Further, the CPU proceeds to step 595 to end this routine once.

  On the other hand, if the first acceleration A1 is greater than or equal to the second acceleration A2, the CPU makes a “No” determination at step 530 to proceed to step 545, and sets the target acceleration Atgt to a value equal to the second acceleration A2. Next, the CPU proceeds to step 540.

(Specific operation-first acceleration determination process)
Next, the first acceleration determination processing routine will be described. When step 520 of FIG. 5 described above is executed, the CPU starts the process from step 700 of FIG. 7 and proceeds to step 705 to determine whether or not a follow-up target vehicle exists.

  Specifically, the CPU determines whether or not a target (another vehicle) exists in an area (following area) where the inter-vehicle distance Dy is smaller than the following limit distance Dyth and the absolute value of the lateral distance Dx is smaller than a predetermined reference width Dxth. Determine whether. The reference width Dxth is an upper limit value of the size of the lateral distance Dx that other vehicles traveling in the same lane as the vehicle 10 can normally take.

  If there is another vehicle in the tracking area, the CPU makes a “Yes” determination at step 705 to proceed to step 710 to identify the tracking target vehicle. Specifically, if there is one other vehicle present in the follow-up range, the CPU specifies the other vehicle as the follow-up target vehicle. On the other hand, if there are a plurality of other vehicles existing in the tracking range, the CPU specifies the other vehicle having the shortest inter-vehicle distance Dy as the tracking target vehicle.

  Next, the CPU proceeds to step 715 to calculate a first inter-vehicle deviation ΔD1 that is a difference between the following inter-vehicle distance Dyf and the first inter-vehicle distance Dyt1. Further, the CPU proceeds to step 720 to determine the first acceleration A1 by applying the inter-vehicle deviation ΔD1 to the map (lookup table) mapA stored in the ROM 22. The first acceleration A1 is set to a larger value as the first inter-vehicle deviation ΔD1 is larger. Next, the CPU proceeds to step 795 to end the present routine tentatively.

  On the other hand, if there is no other vehicle in the follow-up area, the CPU makes a “No” determination at step 705 to proceed to step 725 to calculate a vehicle speed deviation ΔV that is the difference between the set vehicle speed Vset and the vehicle speed Vs. . Further, the CPU proceeds to step 730 to determine the first acceleration A1 by applying the vehicle speed deviation ΔV to the lookup table mapB stored in the ROM 22. The first acceleration A1 is set to a larger value as the vehicle speed deviation ΔV is larger. Next, the CPU proceeds to step 795.

(Specific operation-second acceleration determination process)
Next, the second acceleration determination processing routine will be described. When step 525 in FIG. 5 described above is executed, the CPU starts the process from step 800 in FIG. 8 and proceeds to step 805 to determine whether or not an expected inflow vehicle exists.

The CPU is in an area where the absolute value of the lateral distance Dx is greater than or equal to the reference width Dxth, the absolute value of the lateral distance Dx is decreased, and the absolute value of the relative lateral speed Vx is greater than a predetermined positive reference speed Vxth A mark (another vehicle) is identified as an expected inflow vehicle. In other words, the CPU specifies another vehicle that satisfies either of the following conditions (1) or (2) as an expected inflow vehicle.

Dx ≧ Dxth and Vx <−Vxth (1)
Dx ≦ −Dxth and Vx> Vxth (2)

  If there is a predicted inflow vehicle, the CPU makes a “Yes” determination at step 805 to proceed to step 810 to calculate an inter-vehicle distance Day after completion of the inflow with respect to the predicted inflow vehicle. Next, the CPU determines whether or not the inter-vehicle distance Day after completion of inflow has been calculated for all inflow expected vehicles.

  If there is an expected inflow vehicle for which the inter-vehicle distance Day has not yet been calculated after completion of the inflow, the CPU makes a “No” determination at step 815 to proceed to step 810. On the other hand, if the inter-vehicle distance Day after completion of inflow has been calculated for all expected inflow vehicles, the CPU makes a “Yes” determination at step 815 to proceed to step 820.

  In step 820, the CPU determines whether or not there is an expected vehicle for interruption. That is, the CPU determines that, among the predicted inflow vehicles for which the inter-vehicle distance Day after inflow is calculated, the inter-vehicle distance Day after inflow is a positive value and is smaller than the following inter-vehicle distance Dyf (that is, 0 <Day It is determined whether there is a vehicle that satisfies <Dyf).

  If there is an interrupt predicted vehicle, the CPU makes a “Yes” determination at step 820 to proceed to step 825 to identify an approach predicted vehicle. Specifically, if there is only one predicted interrupt vehicle, the CPU specifies that the predicted interrupt vehicle is an approach predicted vehicle. On the other hand, if there are a plurality of predicted vehicles to be interrupted, the CPU specifies that the vehicle with the shortest inter-vehicle distance Day after the completion of the inflow is the predicted vehicle to be approached among the predicted vehicles to be interrupted.

  Next, the CPU proceeds to step 830 to calculate an inter-vehicle deviation ΔD2 that is the difference between the predicted approach distance Dyn from the approach predicted vehicle and the second inter-vehicle distance Dyt2. Further, the CPU proceeds to step 835 to determine the second acceleration A2 by applying the inter-vehicle deviation ΔD2 to the lookup table mapC stored in the ROM 22. The second acceleration A2 is set to a larger value as the second inter-vehicle deviation ΔD1 is larger. Next, the CPU proceeds to step 895 to end the present routine tentatively.

  If there is no predicted inflow vehicle, the CPU makes a “No” determination at step 805 to proceed to step 840, where the acceleration Amax that is the maximum acceleration that the vehicle 10 can generate is determined as the second acceleration A2. Set to. Next, the CPU proceeds to step 895. Alternatively, if there is no predicted vehicle to be interrupted (including a case in which no follow-up target vehicle exists), the CPU makes a “No” determination at step 820 to proceed to step 840.

  According to the present control device, it is possible to predict the inter-vehicle distance Day after completion of inflow with higher accuracy even at a time immediately after the start of the interrupt by the predicted vehicle. Furthermore, according to the present control device, it is possible to specify the approaching predicted vehicle with higher accuracy even when there are a plurality of predicted interrupting vehicles. As a result, the acceleration As of the vehicle 10 can be appropriately adjusted according to the estimated approach distance Dyn from the predicted approach vehicle from the initial stage of the interruption by the identified approach predicted vehicle, and therefore, the acceleration As suddenly increases. Occurrence of a situation in which the passenger of the vehicle 10 feels uncomfortable due to such a change can be avoided.

<First Modification of Embodiment>
Next, a vehicle travel control apparatus (hereinafter also referred to as “first modification apparatus”) according to a first modification of the embodiment of the present invention will be described. The control device described above calculates the inflow completion time Tcutin by dividing the absolute value of the lateral distance Dx of the predicted inflow vehicle by the inflow average lateral speed Kvx (predetermined constant) (that is, Tcutin = | Dx | / Kvx). In contrast, the first deformation device is different only in that the inflow completion time Tcutin is determined by applying the lateral distance Dx, the relative lateral velocity Vx, and the relative lateral acceleration Ax to a predetermined map. Therefore, this difference will be mainly described below.

  When executing step 810 in FIG. 8, the CPU 21 of the driving assistance ECU 20 according to the first modification device (hereinafter also simply referred to as “CPU”) includes a lateral distance Dx, a lookup table mapD stored in the ROM 22. The inflow completion time Tcutin is determined by applying the relative lateral velocity Vx and the relative lateral acceleration Ax. Here, the relative lateral acceleration Ax is the amount of change per unit time of the relative lateral velocity Vx.

  In general, the inflow completion time Tcutin is set to a larger value as the absolute value of the lateral distance Dx is larger, and is set to a smaller value as the absolute value of the relative lateral velocity Vx is larger. In addition, the inflow completion time Tcutin is set to a larger value as the relative lateral acceleration Ax is larger.

  According to the first deformation device, it is possible to predict the inter-vehicle distance Day after completion of inflow with higher accuracy.

<Second Modification of Embodiment>
Next, a vehicle travel control apparatus (hereinafter also referred to as “second modification apparatus”) according to a second modification of the embodiment of the present invention will be described. In the control apparatus described above, the target acceleration Atgt is set to “first acceleration A1 determined based on the following inter-vehicle distance Dyf” and “second acceleration A2 determined based on the predicted approach distance Dyn with the predicted approaching vehicle”. The smaller value was set. On the other hand, the second deformation device is different only in that the second acceleration A2 is set to the target acceleration Atgt when the approaching predicted vehicle is specified. Therefore, this difference will be mainly described below.

  The CPU 21 (hereinafter also simply referred to as “CPU”) of the driving assistance ECU 20 according to the second modification device performs a “following traveling control processing routine” shown in the flowchart of FIG. Run every time. Steps shown in the flowchart of FIG. 9 in which the same processing as the steps shown in the flowchart of FIG. 5 is executed are denoted by the same step symbols as in FIG.

  When the appropriate timing is reached, the CPU starts the process from step 900 in FIG. 9 and proceeds to step 505. When the CPU ends the process of step 525, the process proceeds to step 930, and determines whether or not the second acceleration A2 is equal to the acceleration Amax.

  As described above, when the approaching predicted vehicle is not specified, the second acceleration A2 is set to the acceleration Amax by the “second acceleration determination processing routine”. Therefore, if an approaching predicted vehicle is not specified, the CPU makes a “Yes” determination at step 930 to proceed to step 535.

  That is, if an approaching predicted vehicle is not specified, the CPU sets the first acceleration A1 as the target acceleration Atgt. On the other hand, if the approaching predicted vehicle has been specified, the CPU makes a “No” determination at step 930 to proceed to step 545 to set the second acceleration A2 as the target acceleration Atgt.

  Note that the CPU proceeds to step 995 after the processing of step 540, and once ends this routine.

  According to the second modification device, from the “setting of the target acceleration Atgt based on the following inter-vehicle distance Dyf with the tracking target vehicle” to the “target based on the predicted approaching distance Dyn with the predicted approaching vehicle at the timing when the approaching predicted vehicle is specified. “Acceleration Atgt setting”.

  As mentioned above, although embodiment of the vehicle travel control apparatus which concerns on this invention was described, this invention is not limited to the said embodiment, A various change is possible unless it deviates from the objective of this invention. For example, the vehicle 10 according to the present embodiment may be equipped with an electric motor that generates the driving force and the braking force of the vehicle 10 in addition to the internal combustion engine. That is, the vehicle 10 may be a hybrid vehicle.

  In addition, in the present embodiment, the set vehicle speed Vset is the vehicle speed Vs at the start of the follow-up running control. However, the set vehicle speed Vset may be set by another procedure by the driver of the vehicle 10. Alternatively, the set vehicle speed Vset may be changed by an operation by the driver after being set once.

  In addition, in the present embodiment, during the execution of the follow-up running control, the engine actuator 52 and the brake actuator 62 may be controlled so that the vehicle speed Vs does not exceed the set vehicle speed Vset regardless of the target acceleration Atgt at that time. That is, when the vehicle speed Vs reaches the set vehicle speed Vset, the target acceleration Atgt may be temporarily changed (overwritten) to “0”.

  In addition, in the present embodiment, the second inter-vehicle distance Dyt2 is smaller than the first inter-vehicle distance Dyt1. However, the second inter-vehicle distance Dyt2 may be a value equal to the first inter-vehicle distance Dyt1, or may be a value greater than the first inter-vehicle distance Dyt1.

  In addition, the vehicle travel control device in the above embodiment determines whether the travel section of the vehicle 10 is a straight section or a curved section based on a signal from the gyro sensor 43. However, the vehicle travel control device includes a GPS receiver and a map database, and the current section of the vehicle 10 acquired by the GPS receiver is applied to the map database so that the travel section of the vehicle 10 is a straight section or a curve. You may determine whether it is an area.

  In addition, in the present embodiment, the radar apparatus 30 is configured by a plurality of millimeter wave radars. However, the radar apparatus 30 may include an infrared radar, an optical camera (including an infrared camera), an ultrasonic sonar, or the like instead of or in addition to the millimeter wave radar.

  In addition, in the present embodiment, the radar device 30 includes a right rear radar device 34 and a left rear radar device 35. That is, the driving assistance ECU 20 was able to detect other vehicles approaching from the rear of the vehicle 10. However, the right rear radar device 34 and the left rear radar device 35 may be omitted.

DESCRIPTION OF SYMBOLS 10 ... Vehicle, 20 ... Driving assistance ECU, 30 ... Radar apparatus, 41 ... ACC operation switch, 42 ... Vehicle speed sensor, 43 ... Gyro sensor, 50 ... Engine ECU, 51 ... Engine sensor, 52 ... Engine actuator, 60 ... Brake ECU 61 ... brake sensor, 62 ... brake actuator.

Claims (1)

Tracking target vehicle specifying means for specifying a tracking target vehicle traveling in front of the host vehicle;
An interrupt predicted vehicle detection means for detecting an interrupt predicted vehicle expected to interrupt between the host vehicle and the tracking target vehicle;
The inter-vehicle distance after completion of interruption, which is the inter-vehicle distance between the predicted predicted vehicle and the host vehicle when the detected predicted predicted vehicle completes the interrupt, every time a predetermined time elapses until the predicted interrupt vehicle completes the interrupt. A vehicle-to-vehicle distance prediction means after completion of interruption obtained by repeated calculation,
When there are a plurality of detected predicted vehicles at the same time, a vehicle having the smallest inter-vehicle distance after completion of the acquired interrupt is identified as the predicted predicted vehicle among the predicted predicted vehicles. When there is only one vehicle, an approach predicted vehicle specifying means for specifying the predicted interrupt vehicle as an approach predicted vehicle;
First calculation means for acquiring an acceleration of the host vehicle necessary for setting the inter-vehicle distance between the tracking target vehicle and the host vehicle as a predetermined first inter-vehicle distance;
Second computing means for obtaining an acceleration of the host vehicle necessary for setting the inter-vehicle distance between the approaching predicted vehicle and the host vehicle as a predetermined second inter-vehicle distance as a second acceleration;
Acceleration mediation means for selecting a smaller one of the first acceleration and the second acceleration as a target acceleration; and
Travel control means for controlling the driving force and braking force of the host vehicle so that the actual acceleration of the host vehicle approaches the target acceleration;
In a vehicle travel control device comprising:
The inter-vehicle distance prediction means after completion of the interruption is
Lateral distance acquisition means for acquiring the current lateral distance of the predicted vehicle to be interrupted relative to the host vehicle by measurement;
Expected time acquisition means for acquiring an expected time from the current time to the time when the predicted interrupt vehicle completes the interrupt by dividing the lateral distance by the virtual lateral relative speed of the predicted predicted vehicle with respect to the host vehicle, as well as,
A distance obtained by adding a product of a change amount per unit time of the reference distance and the predicted time to a reference distance that is a current inter-vehicle distance between the predicted vehicle and the own vehicle after completion of the interrupt. Inter-vehicle distance calculation means after completion of interruption to calculate as the inter-vehicle distance,
A vehicle travel control device comprising:

Images