Braking / driving force control method and braking / driving force control device

Abstract

To alleviate the discomfort of a driver during deceleration of the own vehicle on the basis of a speed profile in accordance with a relative distance between the own vehicle and a target position ahead of the own vehicle.SOLUTION: A brake-drive force control method includes: calculating brake-drive force in accordance with an accelerator operating amount (S1); setting a target position being a position where a vehicular speed of an own vehicle is determined to be a predetermined pre-set vehicular speed (S2); calculating a relative distance between a present position of the own vehicle and the target position (S3); calculating a first target speed of the own vehicle on the basis of the relative distance and a first speed profile in accordance with a distance to the target position (S4); detecting a present vehicular speed of the own vehicle (S5); calculating, in a case where the present speed is equal to or higher than the first target speed, a correction amount in accordance with a difference between the present speed and the first target speed (S6); and controlling brake-drive force of the own vehicle on the basis of post-correction brake-drive force obtained by subtracting the correction amount from the brake-drive force in accordance with the accelerator operating amount (S7, S8).SELECTED DRAWING: Figure 6

Description

[Technical Field]

[0001] The present invention relates to a braking / driving force control method and a braking / driving force control device. [Background technology]

[0002] Patent document 1 proposes a technology that predicts the point where the vehicle will stop, generates a planned speed, which is a target value for the vehicle speed according to the distance to the predicted point, and controls the deceleration of the vehicle so that it follows the generated planned speed. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2012-208829 Summary of the Invention [Problem to be solved by the invention]

[0004] However, there are individual differences among drivers in the speed adjustment for decelerating the vehicle in accordance with the relative distance between the vehicle and a target position ahead of the vehicle, and therefore, if the vehicle is decelerated using a speed profile that differs from the vehicle speed change expected by the driver, the driver may feel uncomfortable. The present invention aims to reduce the sense of discomfort felt by the driver when the host vehicle is decelerated based on a speed profile according to the relative distance between the host vehicle and a target position ahead of the host vehicle. [Means for solving the problem]

[0005] In one embodiment of the present invention, a braking / driving force control method calculates braking / driving forces corresponding to the amount of operation of an accelerator pedal of the host vehicle, sets a target position ahead in the direction of travel of the host vehicle where the vehicle speed will be a predetermined set vehicle speed, calculates the relative distance between the current position of the host vehicle and the target position, calculates a first target speed of the host vehicle based on the relative distance and a first speed profile set as a speed profile corresponding to the distance to the target position, detects the current vehicle speed of the host vehicle, and if the current vehicle speed is greater than or equal to the first target speed, calculates a correction amount corresponding to the difference between the current vehicle speed and the first target speed, calculates corrected braking / driving forces by subtracting the correction amount from the braking / driving forces calculated according to the amount of operation of the accelerator pedal, and controls the braking / driving forces of the host vehicle based on the calculated corrected braking / driving forces. [Effects of the Invention]

[0006] According to the present invention, it is possible to reduce the sense of discomfort felt by the driver when the host vehicle is decelerated based on a speed profile according to the relative distance between the host vehicle and a target position ahead of the host vehicle. [Brief explanation of the drawings]

[0007] [Figure 1] 1 is a diagram showing an example of a schematic configuration of a braking / driving force control device according to an embodiment; [Figure 2] FIG. 4 is a schematic diagram of braking / driving torque according to accelerator pedal depression amount. [Figure 3] 3A and 3B are diagrams illustrating an example of a braking / driving force control method according to an embodiment. [Figure 4] 2 is a block diagram illustrating an example of a functional configuration of a controller in FIG. 1. FIG. [Figure 5] FIG. 3 is a block diagram showing an example of a functional configuration of a correction torque setting unit according to the first embodiment. [Figure 6] 4 is a flowchart illustrating an example of a braking / driving force control method according to an embodiment. [Figure 7] FIG. 10 is a block diagram showing an example of a functional configuration of a correction torque setting unit according to a second embodiment. [Figure 8] FIG. 11 is a block diagram showing an example of a functional configuration of a correction torque setting unit according to a third embodiment. [Figure 9] FIG. 10 is an explanatory diagram of an example of a braking / driving force control method according to a third embodiment. [Figure 10] FIG. 10 is a block diagram showing an example of a functional configuration of a correction torque setting unit according to a fourth embodiment. [Figure 11] FIG. 10 is an explanatory diagram of an example of a braking / driving force control method according to a fourth embodiment. [Figure 12] FIG. 13 is an explanatory diagram of an example of a braking / driving force control method according to a fifth embodiment. [Figure 13] FIG. 13 is a block diagram showing an example of a functional configuration of a correction torque setting unit according to a fifth embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0008] Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the description of the drawings, identical or similar parts are designated by identical or similar reference numerals, and redundant explanations will be omitted. Each drawing is a schematic view, and may differ from the actual product. The embodiments shown below exemplify devices and methods for embodying the technical concept of the present invention, and the technical concept of the present invention is not limited to the devices and methods exemplified in the following embodiments. The technical concept of the present invention can be modified in various ways within the technical scope described in the claims.

[0009] (First embodiment) (composition) Referring to Figure 1, the host vehicle 1 is equipped with a braking / driving force control device 10. The braking / driving force control device 10 controls the driving torque and braking torque (hereinafter, collectively referred to as "braking / driving torque") generated in the host vehicle 1 in accordance with the amount of operation by the driver of an accelerator pedal, which is a driving force instruction operator. Braking / driving torques corresponding to accelerator pedal operation amount Ac will be explained schematically with reference to Figure 2. Braking / driving force control device 10 generates driving torque on the vehicle when accelerator pedal operation amount Ac is greater than a predetermined threshold Ac0, and generates braking torque on the vehicle when operation amount Ac is smaller than the predetermined threshold Ac0. This type of control of braking / driving torques corresponding to accelerator pedal operation amount Ac may be referred to as "one-pedal control" in the following explanation.

[0010] When the operation amount Ac is at its maximum value (100%), the drive torque is at its maximum value (100%), and as the operation amount Ac decreases, the drive torque decreases, and when the operation amount Ac reaches a threshold value Ac0, the drive torque becomes 0. The threshold value Ac0 may be, for example, about one-fourth (25%) of the maximum value of the operation amount Ac. When the operation amount Ac becomes smaller than the threshold value Ac0, the braking torque increases as the operation amount Ac decreases, and when the operation amount Ac reaches 0, the braking torque becomes a predetermined value Td0. Referring to Figure 1, a braking / driving force control device 10 includes a positioning device 11, a map database 12, an external sensor 13, a vehicle sensor 14, a controller 15, and a braking / driving force generation mechanism 16. In the drawing, the map database is referred to as a "map DB."

[0011] The positioning device 11 measures the current position of the vehicle 1. The positioning device 11 may include, for example, a Global Navigation System (GNSS) receiver. The GNSS receiver is, for example, a Global Positioning System (GPS) receiver, and receives radio waves from multiple navigation satellites to measure the current position of the vehicle 1. The positioning device 11 may also be an inertial navigation system. The map database 12 is a database of map information. The map database 12 may be, for example, a map database provided in a car navigation system. The map database 12 may be, for example, high-precision map data suitable as map information for autonomous driving. The controller 15 acquires information about the surrounding conditions of the current position of the host vehicle from the map database 12. For example, the controller 15 acquires information about stop lines present ahead in the traveling direction of the host vehicle 1 from the map database 12.

[0012] The external sensor 13 detects various information (ambient environment information) about the environment surrounding the vehicle 1. The external sensor 13 detects the environment surrounding the vehicle 1, such as objects present around the vehicle 1, the relative positions between the vehicle 1 and the objects, the distance between the vehicle 1 and the objects, and the direction in which the objects are present. The external sensor 13 outputs the detected information about the ambient environment to the controller 15 as ambient environment information. For example, the external sensor 13 detects the relative positions of moving objects and stationary targets, such as other vehicles around the host vehicle 1, relative to the host vehicle 1. Here, stationary targets include, for example, traffic lights provided on the road on which the host vehicle 1 is traveling, lines on the road surface (lane markings, etc.), curbs on the shoulders of the road, guardrails, stop lines and stationary objects (for example, obstacles) on the road on which the host vehicle 1 is traveling. The external sensor 13 may include a monocular camera such as a full HD color camera. The camera captures an image including a recognition target in the environment surrounding the vehicle 1, and outputs the captured image to the controller 15 as ambient environment information. The external sensor 13 may also include a distance measuring device such as a laser range finder (LRF), radar, or a laser radar such as LiDAR (Light Detection and Ranging). The distance measuring device detects the relative position of the vehicle, which is determined by the relative distance and direction to an object present around the vehicle. The distance measuring device outputs the detected distance data to the controller 15 as surrounding environment information.

[0013] The vehicle sensor 14 detects various information (vehicle information) obtained from the host vehicle 1. The vehicle sensor 14 includes, for example, a vehicle speed sensor that detects the traveling speed (vehicle speed) V of the host vehicle 1, a wheel speed sensor that detects the rotational speed of each tire equipped on the host vehicle 1, a three-axis acceleration sensor (G sensor) that detects the acceleration (including deceleration) in three axial directions of the host vehicle 1, a steering angle sensor that detects the steering angle of the steering wheel, a turning angle sensor that detects the turning angle of the steered wheels, a gyro sensor that detects the angular velocity generated in the host vehicle 1, a yaw rate sensor that detects the yaw rate, an accelerator sensor that detects the operation amount Ac of the accelerator pedal of the host vehicle 1, and a brake sensor that detects the brake operation amount by the driver.

[0014] The controller 15 is an electronic control unit (ECU) that controls the braking and driving force of the host vehicle 1. The controller 15 includes a processor 20 and peripheral components such as a storage device 21. The processor 20 may be, for example, a CPU (Central Processing Unit) or an MPU (Micro-Processing Unit). The storage device 21 may include a semiconductor storage device, a magnetic storage device, an optical storage device, etc. The storage device 21 may include memories such as a register, a cache memory, a ROM (Read Only Memory) used as a main memory device, and a RAM (Random Access Memory). The functions of the controller 15 described below are realized by, for example, the processor 20 executing a computer program stored in the storage device 21.

[0015] The controller 15 may be formed by dedicated hardware for executing each of the information processes described below. For example, the controller 15 may include a functional logic circuit configured in a general-purpose semiconductor integrated circuit, such as a programmable logic device (PLD) such as a field-programmable gate array (FPGA).

[0016] The controller 15 sets a torque command value Tf for the driving torque or braking torque to be generated on the wheels of the host vehicle 1 in accordance with the accelerator pedal operation amount Ac, and drives the braking / driving force generation mechanism 16 in accordance with the torque command value Tf to generate the driving torque or braking torque in the host vehicle 1. The process of setting the torque command value Tf by the controller 15 will be described later. The driving / braking force generating mechanism 16 is a drive source connected to the wheels of the host vehicle 1, and is, for example, a drive motor, an internal combustion engine, or a brake actuator that generates driving torque or braking torque on the wheels of the host vehicle 1. In the following, in this embodiment, as an example, the driving / braking force generating mechanism 16 is assumed to be a drive motor. The driving / braking force generating mechanism 16 generates driving torque to drive the host vehicle 1 or braking torque to brake the host vehicle 1 in response to a control signal (torque command value Tf) from the controller 15.

[0017] Next, a description will be given of the process of setting the torque command value by the controller 15. The controller 15 executes so-called one-pedal control, which performs control such that acceleration occurs when the accelerator pedal is depressed and deceleration occurs when the accelerator pedal is released. Please refer to Fig. 3. When the controller 15 detects a stationary target or a moving object present ahead in the traveling direction of the host vehicle 1 using the external sensor 13 or the map database 12, it sets a target position Xtrg, which is a position ahead in the traveling direction of the host vehicle 1, at which the vehicle speed V of the host vehicle 1 is set to a predetermined set vehicle speed Vs. For example, when a stationary target is detected, a point a predetermined distance before the stationary target is set as the target position Xtrg at which the host vehicle 1 is to stop (i.e., the set vehicle speed Vs is 0). Also, for example, when a moving object is detected, the speed of the moving object is set to the predetermined set vehicle speed Vs, and a point a predetermined distance before the moving object is set as the target position Xtrg. Fig. 3 shows an example in which a leading vehicle 2 traveling ahead in the traveling direction of the host vehicle 1 is detected as a moving object.

[0018] The controller 15 calculates the relative distance Xr between the current position of the vehicle 1 and the target position Xtrg, and controls the vehicle speed V of the vehicle 1 using a first speed profile P1 that is set as a speed profile according to the distance to the target position Xtrg. In this case, as described above, there are individual differences among drivers in the speed adjustment for decelerating the vehicle 1 in accordance with the relative distance Xr between the target position Xtrg ahead of the vehicle 1 and the vehicle 1. For this reason, if the vehicle 1 is decelerated using a speed profile that differs from the vehicle speed change expected by the driver, the driver may feel uncomfortable.

[0019] Therefore, the controller 15 of the first embodiment calculates a first target speed V1 of the host vehicle 1 based on the first speed profile P1 and the relative distance Xr, detects the current relative speed Vr of the host vehicle 1 with respect to the target position Xtrg, and if the relative speed Vr is equal to or greater than the first target speed V1, calculates a correction torque Tc according to the difference (Vr-V1) between the relative speed Vr and the first target speed V1. Then, the controller 15 calculates a torque command value Tf by subtracting the correction torque Tc from a basic braking / driving torque Tb calculated in accordance with the accelerator pedal depression amount Ac, and drives the braking / driving force generation mechanism 16 based on the torque command value Tf to control the braking / driving torque of the host vehicle 1.

[0020] In this way, even if the relative speed Vr exceeds the first target speed V1 (i.e., even if the relative speed Vr exceeds the first speed profile P1), the controller 15 of the first embodiment does not directly control the vehicle speed V of the host vehicle 1 so that the relative speed Vr immediately decreases to the first target speed V1, but rather reduces and corrects the basic braking / driving torque Tb corresponding to the accelerator pedal operation amount Ac by the correction torque Tc. This makes it possible to reflect the accelerator pedal operation amount Ac (i.e., the driver's intention) in the speed adjustment of the host vehicle 1. As a result, it is possible to reduce the sense of discomfort felt by the driver when the host vehicle 1 is decelerated based on the first speed profile P1.

[0021] Next, the function of the controller 15 will be described in more detail. Fig. 4 is a block diagram showing an example of the functional configuration of the controller 15. The controller 15 includes a basic braking / driving torque setting unit 30, a target position setting unit 31, a rate limiter 32, a correction torque setting unit 33, and a subtractor 34. The basic braking / driving torque setting unit 30 sets the basic braking / driving torque Tb in accordance with the accelerator pedal operation amount Ac and the vehicle speed V of the host vehicle 1 detected by the vehicle speed sensor. For example, as shown in the characteristic line in Fig. 2, when the accelerator pedal operation amount Ac is greater than a predetermined threshold Ac0, the basic braking / driving torque Tb may be set to a driving torque that increases as the operation amount Ac increases in accordance with the difference between the operation amount Ac and the threshold Ac0. When the accelerator pedal operation amount Ac is smaller than the predetermined threshold Ac0, the basic braking / driving torque Tb may be set to a braking torque that increases as the operation amount Ac decreases in accordance with the difference between the operation amount Ac and the threshold Ac0. Furthermore, the basic braking / driving torque setting unit 30 increases the slope of the basic braking / driving torque Tb as the vehicle speed V of the host vehicle 1 increases, and decreases the slope of the basic braking / driving torque Tb as the vehicle speed V of the host vehicle 1 decreases.

[0022] 4, the target position setting unit 31 sets a target position Xtrg, which is a position ahead in the traveling direction of the host vehicle 1, at which the vehicle speed V of the host vehicle 1 is set to a predetermined set vehicle speed Vs. For example, the target position setting unit 31 detects stationary targets, such as stop lines and stationary objects, that exist ahead in the traveling direction of the host vehicle 1, based on map information in the map database 12 and ambient environment information from the external sensor 13. The target position setting unit 31 sets a point a predetermined distance before the stationary target as the target position Xtrg. Further, for example, the target position setting unit 31 detects a moving object present ahead in the traveling direction of the host vehicle 1 based on the surrounding environment information from the external sensor 13. The target position setting unit 31 moving object A point a predetermined distance before the target position is set as the target position Xtrg. The target position setting unit 31 detects the relative distance Xr between the current position of the host vehicle 1 and the target position Xtrg, and the relative speed Vr of the host vehicle 1 relative to the target position Xtrg. When the target position Xtrg is set with respect to a stationary target, the relative speed Vr becomes the current vehicle speed V of the host vehicle 1, and when the target position Xtrg is set with respect to a moving object, the relative speed Vr becomes the current relative speed of the host vehicle 1 with respect to the moving object.

[0023] The rate limiter 32 limits the speed change of the relative distance Xr output from the target position setting unit 31 and outputs the result to the correction torque setting unit 33. In this way, when the target position Xtrg changes, the rate of change is limited. The correction torque setting unit 33 sets a correction torque Tc based on the relative speed Vr detected by the target position setting unit 31 and the relative distance Xr whose speed change is limited by the rate limiter 32. The correction torque Tc will be described later. Subtractor 34 calculates torque command value Tf by subtracting correction torque Tc from basic braking / driving torque Tb calculated by basic braking / driving torque setting unit 30. Subtractor 34 outputs the calculated torque command value Tf to braking / driving force generation mechanism 16.

[0024] 5 is a block diagram showing an example of the functional configuration of the correction torque setting unit 33 according to the first embodiment. The correction torque setting unit 33 includes a first target speed calculation unit 40a, a subtractor 41, a limiter 42, and a gain multiplication unit 43. The first target speed calculation unit 40a calculates a first target speed V1, which is a target value of the vehicle speed V of the host vehicle 1, based on a first speed profile P1, which is a speed profile according to the distance to the target position Xtrg, and the relative distance Xr. For example, the first speed profile P1 is a speed profile in which the speed is reduced in accordance with the distance to the target position Xtrg to reach the set vehicle speed Vs at the target position Xtrg. When the target position Xtrg is set for a stationary target, the set vehicle speed Vs may be 0, and when the target position Xtrg is set for a moving object, the set vehicle speed Vs may be the speed of the moving object in the traveling direction of the host vehicle 1. The same applies to the second speed profile P2 and the third speed profile P3 described below.

[0025] For example, the first speed profile P1 may be a speed profile that decelerates at a first deceleration G1. The first deceleration G1 may be set to a value equal to or less than the deceleration (for example, 0.1 G) during relatively weak braking in everyday driving. For example, the first speed profile P1 may be set as a calculation formula for the first target speed V1. For example, the first target speed calculation unit 40a may calculate the first target speed V1 based on the following formula (1). V1=(2×G1×Xr) 1 / 2 +Vs …(1) Furthermore, for example, the first speed profile P1 may be set as map data of the first target speed V1 versus the distance to the target position Xtrg. The same applies to the second speed profile P2 and the third speed profile P3 described below.

[0026] The subtractor 41 calculates a speed difference (Vr-V1) by subtracting the first target speed V1 from the relative speed Vr. The limiter 42 limits the lower limit of the speed difference (Vr-V1) calculated by the subtractor 41. For example, the limiter 42 may limit the lower limit of the speed difference (Vr-V1) to a value ThL that is equal to or greater than 0. For example, the limiter 42 may limit the lower limit of the speed difference (Vr-V1) to "0." This makes it possible to stop the output of the correction torque Tc when the relative speed Vr is equal to or less than the first target speed V1. The gain multiplication unit 43 multiplies the speed difference (Vr-V1) limited by the limiter 42 by an adjustment gain K1 corresponding to the relative distance Xr, and calculates the product K1 x (Vr-V1) as the correction torque Tc. For example, the adjustment gain K1 may be a gain that is larger when the relative distance Xr is short than when it is long. For example, the adjustment gain K1 may be a gain that is larger the shorter the relative distance Xr. This makes it possible to increase the correction torque Tc for the speed difference (Vr-V1) the shorter the relative distance Xr is, and even if the speed difference (Vr-V1) is the same, the basic braking / driving torque Tb can be reduced and corrected by a larger correction torque Tc as the host vehicle 1 approaches the target position Xtrg.

[0027] FIG. 6 is a flowchart illustrating an example of a braking / driving force control method according to an embodiment. In step S1, the basic braking / driving torque setting unit 30 sets the basic braking / driving torque Tb. In step S2, the target position setting unit 31 sets the target position Xtrg. In step S3, the target position setting unit 31 calculates the relative distance Xr between the host vehicle 1 and the target position Xtrg. In step S4, the correction torque setting unit 33 calculates a first target speed V1. In step S5, the target position setting unit 31 detects the relative speed Vr of the host vehicle 1 with respect to the target position Xtrg. In step S6, the correction torque setting unit 33 calculates the correction torque Tc. In step S7, the subtractor 34 calculates the torque command value Tf by subtracting the correction torque Tc from the basic braking / driving torque Tb. In step S8, the braking / driving force generation mechanism 16 generates, in accordance with the torque command value Tf, a driving torque for driving the host vehicle 1 or a braking torque for braking the host vehicle 1. Then, the process ends.

[0028] (Second embodiment) 7 is a block diagram showing an example of the functional configuration of the correction torque setting unit 33 of the second embodiment. The correction torque setting unit 33 of the second embodiment has a configuration similar to that of the correction torque setting unit 33 of the first embodiment, and the same or similar components are denoted by the same reference numerals. The correction torque setting unit 33 of the second embodiment calculates the correction torque Tc based on the ratio (Vr-V1) / V1 of the speed difference (Vr-V1) between the relative speed Vr and the first target speed V1 with respect to the first target speed V1. Note that the ratio (Vr-V1) / V1 can be transformed into (Vr / V1-1), so it can be considered that the correction torque setting unit 33 calculates the correction torque Tc based on the ratio (Vr / V1) of the relative speed Vr with respect to the first target speed V1.

[0029] The correction torque setting unit 33 of the second embodiment includes a ratio calculation unit 44. The ratio calculation unit 44 of the second embodiment calculates, as a correction coefficient α, a ratio (Vr-V1) / V1 of the speed difference (Vr-V1) between the relative speed Vr and the first target speed V1 to the first target speed V1. The limiter 42 limits the correction coefficient α calculated by the ratio calculation unit 44 to a value within a range of a lower limit value αmin or more and an upper limit value αmax or less. The lower limit value αmin is set to a value equal to or greater than 0. This makes it possible to stop the output of the correction torque Tc when the relative speed Vr is equal to or less than the first target speed V1. For example, the lower limit value αmin may be set to "0." The upper limit value αmax may be set appropriately depending on the maximum allowable value of the correction torque Tc that corrects and decreases the basic braking / driving torque Tb. For example, the upper limit value αmax may be set to "2".

[0030] A gain multiplication unit 43 multiplies the correction coefficient α limited by the limiter 42 by an adjustment gain K1 to calculate the product as the correction torque Tc. The value of the adjustment gain K1 may be fixed, or may be an adjustment gain K1 that corresponds to the relative distance Xr, as in the first embodiment. This also applies to the third to fifth embodiments described below. Figure 3 or the above formula ( 1 ), the closer the host vehicle 1 is to the target position Xtrg, the lower the first target speed V1 becomes. Therefore, the closer the host vehicle 1 is to the target position Xtrg, the larger the correction coefficient α becomes. Therefore, the closer the host vehicle 1 is to the target position Xtrg, the larger the correction torque Tc that can be used to reduce and correct the basic braking / driving torque Tb.

[0031] (Third embodiment) 8 is a block diagram showing an example of the functional configuration of the correction torque setting unit 33 of the third embodiment. The correction torque setting unit 33 of the third embodiment has a configuration similar to that of the correction torque setting unit 33 of the second embodiment, and the same or similar components are denoted by the same reference numerals. The correction torque setting unit 33 of the third embodiment includes a second target speed calculation unit 40b. The second target speed calculation unit 40b calculates a second target speed V2, which is a target value for the vehicle speed V of the host vehicle 1, based on a second speed profile P2 set as a speed profile according to the distance to the target position Xtrg and the relative distance Xr.

[0032] For example, the second speed profile P2 is a speed profile in which the vehicle speed is decelerated at a second deceleration G2 that is greater than the first deceleration G1 of the first speed profile P1, and reaches the set vehicle speed Vs at the target position Xtrg. The second deceleration G2 may be set to a value that is approximately the deceleration (for example, 0.2 G) that occurs during relatively strong braking in everyday driving. For example, the second target speed calculation section 40b may calculate the second target speed V2 based on the following equation (2). V2=(2×G2×Xr) 1 / 2 +Vs …(2)

[0033] The ratio calculation unit 44 of the third embodiment calculates the correction coefficient α as the ratio (Vr-V1) / (V2-V1) of the speed difference (Vr-V1) between the relative speed Vr and the first target speed V1 to the speed difference (V2-V1) between the second target speed V2 and the first target speed V1. FIG. 9 schematically shows the speed difference (V2-V1) between the second target speed V2 and the first target speed V1, and the speed difference (Vr-V1) between the relative speed Vr and the first target speed V1. The functions of the limiter 42 and the gain multiplication unit 43 in the third embodiment are similar to the functions of the limiter 42 and the gain multiplication unit 43 in the second embodiment.

[0034] Therefore, when the relative speed Vr is equal to or less than the first target speed V1, the value of the correction torque Tc is set to "0." When the relative speed Vr is greater than the first target speed V1 and equal to or less than the second target speed V2, the value of the correction torque Tc is set to K1×(Vr−V1) / (V2−V1). When the relative speed Vr is greater than the second target speed V2, the value of the correction torque Tc is set to K1×(Vr−V1) / (V2−V1) until it is limited by the upper limit value K1×αmax.

[0035] 9, as the host vehicle 1 approaches the target position Xtrg, the speed difference (V2-V1) between the second target speed V2 and the first target speed V1 becomes smaller and the correction coefficient α becomes larger. Therefore, as the host vehicle 1 approaches the target position Xtrg, the basic braking / driving torque Tb can be reduced and corrected by a larger correction torque Tc. Furthermore, when the relative speed Vr of the host vehicle changes from the first target speed V1 based on the first speed profile P1 to the second target speed V2 based on the second speed profile P2, the correction coefficient α changes from "0" to "1." Therefore, the value of the correction torque Tc can be set to "0" until the relative speed Vr exceeds the first speed profile P1. On the other hand, when the relative speed Vr exceeds the first speed profile P1, the correction torque Tc increases as the relative speed Vr increases, and when the relative speed Vr reaches the second target speed V2, the value of the correction torque Tc becomes "K1". Therefore, by appropriately setting the adjustment gain K1, it is possible to arbitrarily set the value of the correction torque Tc when the relative speed Vr reaches the second target speed V2 on the second speed profile P2.

[0036] (Fourth embodiment) 10 is a block diagram showing an example of the functional configuration of the correction torque setting unit 33 of the fourth embodiment. The correction torque setting unit 33 of the fourth embodiment has a configuration similar to that of the correction torque setting unit 33 of the third embodiment, and the same or similar components are denoted by the same reference numerals. The correction torque setting unit 33 of the third embodiment includes a third target speed calculation unit 40c, a switching unit 45, and an adder . The third target speed calculation unit 40c calculates a third target speed V3, which is a target value of the vehicle speed V of the host vehicle 1, based on a third speed profile P3 set as a speed profile according to the distance to the target position Xtrg and the relative distance Xr.

[0037] For example, the third speed profile P3 is a speed profile in which the vehicle speed is decelerated at a third deceleration G3 that is greater than the second deceleration G2 of the second speed profile P2, and the vehicle speed reaches the set vehicle speed Vs at the target position Xtrg. The third deceleration G3 may be set to a value equal to or greater than the deceleration (for example, 0.3 G) that occurs during sudden braking, such as to prevent a rear-end collision. For example, the third target speed calculation section 40c may calculate the third target speed V3 based on the following equation (3). V3=(2×G3×Xr) 1 / 2 +Vs…( 3 )

[0038] A ratio calculation unit 44 of the fourth embodiment receives the relative speed Vr, the first input speed VL, and the second input speed VH as inputs. The ratio calculation unit 44 calculates the correction coefficient α as the ratio (Vr-VL) / (VH-VL) of the speed difference (Vr-VL) between the relative speed Vr and the first input speed VL to the speed difference (VH-VL) between the second input speed VH and the first input speed VL. The switching unit 45 switches the first input speed VL input to the ratio calculation unit 44 between the first target speed V1 and the second target speed V2 depending on whether the relative speed Vr is greater than the second target speed V2. Also, the switching unit 45 switches the second input speed VH input to the ratio calculation unit 44 between the second target speed V2 and the third target speed V3 depending on whether the relative speed Vr is greater than the second target speed V2.

[0039] Specifically, the relative speed Vr is equal to the second target speed V2 less than In this case, the switching unit 45 inputs the first target speed V1 and the second target speed V2 as the first input speed VL and the second input speed VH, respectively, to the ratio calculation unit 44. In this case, the ratio calculation unit 44 calculates, as the correction coefficient α, the ratio (Vr-V1) / (V2-V1) of the speed difference (Vr-V1) between the relative speed Vr and the first target speed V1 to the speed difference (V2-V1) between the second target speed V2 and the first target speed V1. Relative velocity Vr is the second target velocity V2 The above In this case, the switching unit 45 inputs the second target speed V2 and the third target speed V3 as the first input speed VL and the second input speed VH to the ratio calculation unit 44. In this case, the ratio calculation unit 44 calculates the ratio (Vr-V2) / (V3-V2) of the speed difference (Vr-V2) between the relative speed Vr and the second target speed V2 to the speed difference (V3-V2) between the third target speed V3 and the second target speed V2 as the correction coefficient α. FIG. 11 schematically shows the speed difference (V3-V2) between the third target speed V3 and the second target speed V2, and the speed difference (Vr-V2) between the relative speed Vr and the second target speed V2.

[0040] See Fig. 10. Furthermore, when the relative speed Vr is greater than the second target speed V2, the switching unit 45 sets the value of the offset value Offset that offsets the correction coefficient α to "1." When the relative speed Vr is equal to or less than the second target speed V2, the switching unit 45 sets the value of the offset value Offset to "0." The function of the limiter 42 in the fourth embodiment is similar to the function of the limiter 42 in the second and third embodiments. The adder 46 adds the offset value Offset to the correction coefficient α limited by the limiter 42 to obtain a sum (α+Offset), and inputs the sum to the gain multiplication unit 43. The gain multiplication unit 43 multiplies the sum (α+Offset) by the adjustment gain K1 to calculate the product K1×(α+Offset) as the correction torque Tc.

[0041] Therefore, when the relative speed Vr is equal to or less than the first target speed V1, the value of the correction torque Tc is set to "0." When the relative speed Vr is greater than the first target speed V1 and equal to or less than the second target speed V2, the value of the correction torque Tc is set to K1 × (Vr - V1) / (V2 - V1). When the relative speed Vr is greater than the second target speed V2 and equal to or less than the third target speed V3, the value of the correction torque Tc is set to K1 × ((Vr - V2) / (V3 - V2) + 1). When the relative speed Vr is greater than the third target speed V3, the value of the correction torque Tc is set to K1 × ((Vr - V2) / (V3 - V2) + 1) until it is limited by the upper limit value K1 × (αmax + 1). In the configuration example of FIG. 10, the adder 46 is provided after the limiter 42, but instead it may be provided between the ratio calculation unit 44 and the limiter 42.

[0042] As can be seen from Fig. 9, the closer the host vehicle 1 is to the target position Xtrg, the smaller the speed difference (V2-V1) between the second target speed V2 and the first target speed V1. Also, as can be seen from Fig. 11, the closer the host vehicle 1 is to the target position Xtrg, the smaller the speed difference (V3-V2) between the third target speed V3 and the second target speed V2. For this reason, the correction coefficient α becomes larger as the host vehicle 1 approaches the target position Xtrg, and therefore the basic braking / driving torque Tb can be corrected and decreased by a large correction torque Tc. Furthermore, similarly to the third embodiment, the value of the correction torque Tc can be set to "0" until the relative speed Vr exceeds the first speed profile P1. Furthermore, by appropriately setting the adjustment gain K1, the correction torque Tc when the relative speed Vr reaches the second target speed V2 on the second speed profile P2 can be set to an arbitrary value "K1."

[0043] Furthermore, when the relative speed Vr of the host vehicle changes from the second target speed V2 based on the second speed profile P2 to the third target speed V3 based on the third speed profile P3, the sum of the correction coefficient α and the offset value Offset (α+Offset) changes from "1" to "2". Therefore, by appropriately setting the adjustment gain K1, the correction torque Tc when the relative speed Vr reaches the third target speed V3 on the third speed profile P3 can be set to an arbitrary value "2 x K1".

[0044] (Fifth embodiment) Please refer to Fig. 12. When a moving object 2 present ahead in the traveling direction of the host vehicle 1 is detected, the correction torque setting unit 33 in the first to fourth embodiments decelerates the host vehicle 1 based on a speed profile in which the relative speed Vr to the moving object 2 becomes the set vehicle speed Vs at a target position Xtrg a predetermined distance before the moving object. For this reason, when the moving object (the preceding vehicle 2 in the example of Fig. 12) is decelerating, it may not be possible to make the relative speed Vr become the set vehicle speed Vs at the target position Xtrg. Therefore, when the moving object 2 is decelerating, the correction torque setting unit 33 of the fifth embodiment increases the correction torque Tc indicated by the dashed line in FIG. 12 to the correction torque Tc indicated by the solid line. Specifically, the acceleration a of the moving object 2 detected ahead in the traveling direction of the host vehicle 1 is detected, and the larger the detected acceleration a, the smaller the correction torque Tc. In other words, the larger the deceleration, which is the acceleration with a negative value, the larger the correction torque Tc.

[0045] Fig. 13 is a block diagram showing an example of the functional configuration of the correction torque setting unit 33 of the fifth embodiment. The correction torque setting unit 33 of the fifth embodiment has a configuration similar to that of the correction torque setting unit 33 of the first embodiment described with reference to Fig. 5, and the same components are denoted by the same reference numerals. The correction torque setting unit 33 of the fifth embodiment includes an acceleration calculation unit 47, a gain multiplication unit 48, and an adder 49.

[0046] When a point a predetermined distance before a moving object in front of the vehicle in the direction of travel is set as the target position Xtrg, the acceleration calculation unit 47 calculates the relative acceleration of the moving object with respect to the vehicle 1 by differentiating the relative velocity Vr. The acceleration calculation unit 47 may calculate the acceleration of the moving object. In this case, the acceleration calculation unit 47 acquires information on the vehicle speed V of the host vehicle 1 from the vehicle speed sensor of the vehicle sensor 14, and differentiates the vehicle speed V to calculate the acceleration of the host vehicle 1. The acceleration calculation unit 47 may calculate the sum of the acceleration and relative acceleration of the host vehicle 1 as the acceleration of the moving object. Hereinafter, the relative acceleration calculated by the acceleration calculation unit 47 or the acceleration of the moving object may be collectively referred to as "acceleration a."

[0047] The gain multiplication unit 48 multiplies the acceleration a calculated by the acceleration calculation unit 47 by a negative adjustment gain K2 to calculate the product as the second correction torque Tc2. Therefore, when the acceleration a indicates deceleration (i.e., when the acceleration a is less than 0), the second correction torque Tc2 has a positive value. For example, the adjustment gain K2 may be a negative gain whose absolute value is larger when the relative distance Xr is short than when it is long. For example, the adjustment gain K2 may be a negative gain whose absolute value is larger as the relative distance Xr is shorter. This allows the basic braking / driving torque Tb to be reduced and corrected by a larger second correction torque Tc2 as the host vehicle 1 approaches the target position Xtrg.

[0048] The gain multiplication unit 43 multiplies the speed difference (Vr-V1) limited by the limiter 42 by an adjustment gain K1 to calculate the product as a first correction torque Tc1. The adder 49 calculates the sum of the first correction torque Tc1 and the second correction torque Tc2 as the correction torque Tc, and outputs it to the subtractor 34 shown in FIG. The configuration shown in FIG. 13 is a configuration in which an acceleration calculation unit 47, a gain multiplication unit 48, and an adder 49 are added to the correction torque setting unit 33 of the first embodiment described with reference to FIG. 5, but the acceleration calculation unit 47, the gain multiplication unit 48, and the adder 49 may also be added to the correction torque setting unit 33 of the second embodiment described with reference to FIG. 7, the correction torque setting unit 33 of the third embodiment described with reference to FIG. 8, and the correction torque setting unit 33 of the fourth embodiment described with reference to FIG. 10 in the same manner.

[0049] (Effects of the embodiment) (1) The controller 15 calculates the braking / driving force according to the amount of operation of the accelerator pedal of the host vehicle 1, sets a target position ahead in the direction of travel of the host vehicle 1, which is a position where the vehicle speed of the host vehicle 1 is set to a predetermined set vehicle speed, calculates the relative distance between the current position of the host vehicle 1 and the target position, calculates a first target speed of the host vehicle 1 based on the relative distance and a first speed profile set as a speed profile according to the distance to the target position, detects the current vehicle speed of the host vehicle 1, and if the current vehicle speed is equal to or greater than the first target speed, calculates a correction amount according to the difference between the current vehicle speed and the first target speed, calculates corrected braking / driving forces by subtracting the correction amount from the braking / driving forces calculated according to the amount of operation of the accelerator pedal, and controls the braking / driving forces of the host vehicle 1 based on the calculated corrected braking / driving forces. In this way, even if the current vehicle speed exceeds the first target speed (i.e., even if the current vehicle speed exceeds the first speed profile), the controller 15 does not directly control the vehicle speed of the vehicle 1 so that the current vehicle speed immediately decreases to the first target speed, but rather reduces the braking / driving force in accordance with the amount of operation of the accelerator pedal. Therefore, the operation amount of the accelerator pedal (i.e., the driver's intention) can be reflected in the speed adjustment of the host vehicle 1. As a result, it is possible to reduce the sense of discomfort felt by the driver when decelerating the host vehicle 1 based on the first speed profile.

[0050] (2) The controller 15 may calculate a larger correction amount as the relative distance becomes shorter. As a result, the braking / driving force can be reduced and corrected by a larger correction amount as the host vehicle 1 approaches the target position. (3) The first speed profile may be a speed profile in which the vehicle speed is decelerated at a predetermined first deceleration to reach a set vehicle speed at the target position. The controller 15 may calculate a larger correction amount as the ratio of the difference obtained by subtracting the first target speed from the current vehicle speed and dividing it by the first target speed increases. As a result, the braking / driving force can be reduced and corrected by a larger correction amount as the host vehicle 1 approaches the target position.

[0051] (4) The first speed profile may be a speed profile in which the host vehicle 1 decelerates at a predetermined first deceleration to reach the set vehicle speed at the target position. The controller 15 may calculate a second target speed of the host vehicle 1 based on the relative distance and the second speed profile, which is set as a speed profile according to the distance to the target position and in which the host vehicle decelerates at a second deceleration greater than the first deceleration to reach the set vehicle speed at the target position, and may calculate a larger correction amount as the ratio of the difference obtained by subtracting the first target speed from the current vehicle speed divided by the difference obtained by subtracting the first target speed from the second target speed increases. As a result, the braking / driving force can be reduced and corrected by a larger correction amount as the host vehicle 1 approaches the target position. Furthermore, the value of the correction amount can be set to "0" until the current vehicle speed exceeds the first speed profile. On the other hand, when the current vehicle speed exceeds the first speed profile, the correction amount is increased as the difference between the current vehicle speed and the first target speed increases, and the value of the correction amount when the current vehicle speed reaches the second target speed on the second speed profile can be set arbitrarily.

[0052] (5) The controller 15 calculates a third target speed of the vehicle 1 based on the relative distance and a third speed profile, which is set as a speed profile according to the distance to the target position and which decelerates at a third deceleration greater than the second deceleration to reach the set vehicle speed at the target position. When the current vehicle speed is equal to or greater than the first target speed and less than the second target speed, the controller 15 may calculate a larger correction amount the greater the ratio of the difference obtained by subtracting the first target speed from the current vehicle speed divided by the difference obtained by subtracting the first target speed from the second target speed. When the current vehicle speed is equal to or greater than the second target speed and less than the third target speed, the controller 15 may calculate a larger correction amount the greater the ratio of the difference obtained by subtracting the second target speed from the current vehicle speed divided by the difference obtained by subtracting the second target speed from the third target speed.

[0053] As a result, the braking / driving force can be reduced and corrected by a larger correction amount as the host vehicle 1 approaches the target position. Furthermore, the value of the correction amount can be set to "0" until the current vehicle speed exceeds the first speed profile. On the other hand, when the current vehicle speed exceeds the first speed profile, the correction amount is increased as the difference between the current vehicle speed and the first target speed increases, so that the value of the correction amount when the current vehicle speed reaches the second target speed on the second speed profile can be set arbitrarily. Furthermore, when the current vehicle speed exceeds the second speed profile, the correction amount is increased as the difference between the current vehicle speed and the second target speed increases, so that the value of the correction amount when the current vehicle speed reaches the third target speed on the third speed profile can be set arbitrarily.

[0054] (6) The controller 15 may detect the position of a stationary target ahead of the vehicle 1 and set a point a predetermined distance before the position of the detected stationary target as a target position for stopping the vehicle 1. The stationary target may be, for example, a stationary object ahead of the vehicle 1 or a stop line. This allows the host vehicle 1 to decelerate so that it can stop in front of the stationary target ahead of the host vehicle 1. (7) Controller 15 may limit the rate of change of the set target position, thereby preventing a sudden change in braking / driving force due to a sudden change in the target position.

[0055] (8) The controller 15 may detect the position of a moving object ahead of the host vehicle 1, and set a point a predetermined distance before the detected position of the moving object as the target position. In this case, the controller 15 may detect the relative speed of the host vehicle 1 with respect to the detected moving object, and calculate the correction amount according to the difference between the detected relative speed and the first target speed. This allows the host vehicle 1 to decelerate so that the relative speed between the host vehicle 1 and the moving object becomes zero just before the moving object ahead of the host vehicle 1.

[0056] (10) The controller 15 may detect the acceleration of a moving object detected in the traveling direction of the host vehicle 1, and may decrease the correction amount as the detected acceleration increases. Alternatively, the relative acceleration of a detected moving object relative to the host vehicle 1 in the traveling direction of the host vehicle 1 may be detected, and the correction amount may be reduced as the detected relative acceleration increases. This makes it easier to control the relative speed between the host vehicle 1 and the moving object to the set vehicle speed Vs at the target position in front of the moving object, even if the moving object is decelerating. [Explanation of symbols]

[0057] 1... host vehicle, 2... preceding vehicle, 10... braking / driving force control device, 11... positioning device, 12... map database, 13... external sensor, 14... vehicle sensor, 15... controller, 16... braking / driving force generation mechanism, 20... processor, 21... storage device, 30... basic braking / driving torque setting unit, 31... target position setting unit, 32... rate limiter, 33... correction torque setting unit, 34, 41... subtractor, 40a... first target speed calculation unit, 40b... second target speed calculation unit, 40c... third target speed calculation unit, 42... limiter, 43... gain multiplication unit, 44... ratio calculation unit, 45... switching unit, 46, 49... adder, 47... acceleration calculation unit, 48... gain multiplication unit

Claims

1. Calculating braking / driving force according to the amount of accelerator pedal operation of the vehicle; a target position is set in front of the host vehicle in a traveling direction, the target position being a position at which the host vehicle speed is set to a predetermined set vehicle speed; Calculating a relative distance between the current position of the vehicle and the target position; calculating a first target speed of the host vehicle based on a first speed profile set as a speed profile according to a distance to the target position and the relative distance; Detecting a current vehicle speed, which is a current vehicle speed of the subject vehicle; When the current vehicle speed is equal to or greater than the first target speed, a correction amount is calculated according to a difference between the current vehicle speed and the first target speed; calculating corrected braking / driving forces by subtracting the correction amount from the braking / driving forces calculated in accordance with the accelerator pedal depression amount; controlling the braking / driving force of the host vehicle based on the calculated corrected braking / driving force; A braking / driving force control method characterized by the above.

2. 2. The braking / driving force control method according to claim 1, wherein the correction amount calculated for the difference between the current vehicle speed and the first target speed increases as the relative distance decreases.

3. the first speed profile is a speed profile in which the vehicle speed is decelerated at a predetermined first deceleration to reach the set vehicle speed at the target position, The correction amount is calculated so that the larger the ratio of the difference obtained by subtracting the first target speed from the current vehicle speed divided by the first target speed is, the larger the correction amount is calculated.

3. The braking / driving force control method according to claim 1 or 2.

4. the first speed profile is a speed profile in which the vehicle speed is decelerated at a predetermined first deceleration to reach the set vehicle speed at the target position, calculating a second target speed of the host vehicle based on the relative distance and a second speed profile that is set as a speed profile according to the distance to the target position and that decelerates the host vehicle at a second deceleration that is greater than the first deceleration to reach the set vehicle speed at the target position; The correction amount is calculated so that the larger the ratio of the difference obtained by subtracting the first target speed from the current vehicle speed divided by the difference obtained by subtracting the first target speed from the second target speed is, the larger the correction amount is calculated.

3. The braking / driving force control method according to claim 1 or 2.

5. calculating a third target speed of the host vehicle based on the relative distance and a third speed profile that is set as a speed profile according to the distance to the target position and that decelerates the host vehicle at a third deceleration that is greater than the second deceleration to reach the set vehicle speed at the target position; when the current vehicle speed is equal to or greater than the first target speed and less than the second target speed, the larger the ratio of a difference obtained by subtracting the first target speed from the current vehicle speed divided by a difference obtained by subtracting the first target speed from the second target speed, the larger the correction amount calculated; When the current vehicle speed is equal to or greater than the second target speed and less than the third target speed, the larger the ratio of the difference obtained by subtracting the second target speed from the current vehicle speed divided by the difference obtained by subtracting the second target speed from the third target speed, the larger the correction amount calculated.

5. The braking / driving force control method according to claim 4.

6. Detecting the position of a stationary target ahead of the vehicle; setting a point a predetermined distance before the detected position of the stationary target as the target position; The set vehicle speed is set to 0.

6. The braking / driving force control method according to claim 1, wherein the braking / driving force control method is a braking / driving force control method.

7. 7. The braking / driving force control method according to claim 6, wherein the stationary object is a stationary object or a stop line ahead of the host vehicle.

8. A braking / driving force control method according to claim 1, characterized in that when the target position changes, the rate of change of the target position is limited by a rate limiter.

9. Detecting the position of a moving object ahead of the vehicle; setting a point a predetermined distance before the detected position of the moving object as the target position; 6. The braking / driving force control method according to claim 1, wherein the braking / driving force control method is a braking / driving force control method.

10. Detecting a relative speed of the host vehicle with respect to the detected moving object; calculating the correction amount according to a difference between the detected relative speed and the first target speed; 10. The braking / driving force control method according to claim 9.

11. Detecting the acceleration of the detected moving object in the traveling direction of the host vehicle; The greater the detected acceleration, the smaller the correction amount.

11. The braking / driving force control method according to claim 10.

12. Detecting a relative acceleration of the detected moving object with respect to the host vehicle in a traveling direction of the host vehicle; The larger the detected relative acceleration is, the smaller the correction amount is.

11. The braking / driving force control method according to claim 10.

13. Accelerator pedal and a braking / driving force generation mechanism that generates braking / driving forces for the host vehicle; a controller that calculates braking / driving forces corresponding to an operation amount of the accelerator pedal, sets a target position ahead in a traveling direction of the host vehicle, which is a position where the vehicle speed of the host vehicle is set to a predetermined set vehicle speed, calculates a relative distance between a current position of the host vehicle and the target position, calculates a first target speed of the host vehicle based on the relative distance and a first speed profile set as a speed profile corresponding to the distance to the target position, detects a current vehicle speed of the host vehicle, and, when the current vehicle speed is equal to or greater than the first target speed, calculates a correction amount corresponding to a difference between the current vehicle speed and the first target speed, calculates corrected braking / driving forces by subtracting the correction amount from the braking / driving forces calculated in accordance with the operation amount of the accelerator pedal, and controls the braking / driving force generation mechanism based on the calculated corrected braking / driving forces; A braking / driving force control device comprising:

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