Driving support devices, driving support methods and procedures

Abstract

A driving support device, driving support method, and procedure effectively suppress understeer angle in a first steering control and effectively suppress oversteer angle in a second steering control. The driving support device (1) implements collision avoidance control by controlling the rudder angle (θs) when an obstacle (OB) is detected in the area ahead, so that its own vehicle (100) travels along a target trajectory (Rt) that avoids collision with the obstacle without leaving the driving lane (LA1). The driving support device includes: a steering control unit (10, 60) that performs a first steering control (increasing rudder angle to avoid collision) and a second steering control (including decreasing rudder angle to prevent leaving the driving lane); and a damping control unit (10, 60) that performs damping control by applying a steering resistance calculated based on the rudder angle velocity (dθs / dt) to the steering wheel. The damping control unit performs damping control during the execution of the second steering control.

Description

Technical Field

[0001] This disclosure relates to driving support devices, driving support methods and procedures, and to collision avoidance control technology for avoiding collisions between a vehicle and an obstacle. Background Technology

[0002] For example, Patent Document 1 discloses a device in an electric power steering system installed in a vehicle that, when an increase in steering wheel turning is detected by the driver, applies an auxiliary torque in the direction of increasing steering wheel turning to the steering shaft, and when a return steering wheel turning is detected, applies an auxiliary torque in the direction of returning steering wheel turning to the steering shaft, and applies a damping torque to prevent excessive return steering.

[0003] Existing technical documents

[0004] Patent documents

[0005] Patent Document 1: Japanese Patent Application Publication No. 2005-007990 Summary of the Invention

[0006] As a driving support device mounted on a vehicle, a collision avoidance control driving support device is known that automatically controls the rudder angle of the vehicle's steering wheel to avoid collision when a high probability of collision is detected in front of the vehicle. The collision avoidance control performs a first steering control to avoid a collision between the vehicle and the obstacle, followed by a second steering control to prevent the vehicle from leaving the driving lane. In the first steering control, a steering increase steering is performed that increases the rudder angle. In the second steering control, a steering return steering is performed sequentially, returning the rudder angle increased by the first steering control to a neutral position; a steering increase steering is performed, increasing the rudder angle from the neutral position in the opposite direction to the steering direction of the first steering control; and a steering return steering is performed, returning the rudder angle to a neutral position again.

[0007] In collision avoidance control, if the self-aligning torque acting on the steering wheel in the return direction during the execution of the first steering control is added to the second steering control, it will cause the second steering control to increase steering, resulting in overshoot due to excessive rudder angle. To prevent such overshoot, a damping torque can be applied to the collision avoidance control.

[0008] However, if damping torque is applied to both the first and second steering controls, the first steering control may become insufficient in rudder angle, making it unable to effectively avoid collisions with obstacles. Furthermore, when applying the technology described in Patent Document 1 to collision avoidance control, the damping torque is only applied to the rudder return steering in Patent Document 1. Therefore, it is impossible to apply damping torque to the rudder turns performed in the second steering control, resulting in the inability to suppress overshoot.

[0009] This disclosure is made to solve the aforementioned problems. Specifically, one of the objectives of this disclosure is to effectively suppress understeer angle in the first steering control and to effectively suppress oversteer angle in the second steering control.

[0010] The device disclosed herein is a driving support device (1) that, when an obstacle (OB) with a high probability of collision with the vehicle (100) is detected in the area in front of and to the front side of the vehicle (100), implements collision avoidance control by controlling the rudder angle (θs) of the steering wheel of the vehicle (100) so that the vehicle (100) travels along a target trajectory (Rt) that avoids collision with the obstacle (OB) without leaving the driving lane (LA1).

[0011] The driving support device (1) includes:

[0012] The steering control units (10, 60), to avoid a collision between the vehicle (100) and the obstacle (OB), execute a first steering control that increases the rudder angle (θs), and after executing this first steering control, to prevent the vehicle (100) from leaving the driving lane (LA1), execute a second steering control that includes a second steering control that decreases the rudder angle (θs) to return to normal steering.

[0013] The damping control unit (10, 60) performs damping control during the execution of the collision avoidance control, calculating the steering resistance based on the rudder angular velocity (dθs / dt) and applying the calculated steering resistance to the steering wheel.

[0014] The damping control units (10, 60),

[0015] The damping control is not executed during the execution of the first steering control, but is executed during the execution of the second steering control.

[0016] The method disclosed herein is a driving support method that, when an obstacle (OB) with a high probability of collision with the vehicle (100) is detected in the area in front of and to the front side of the vehicle (100), implements a collision avoidance control by controlling the rudder angle (θs) of the steering wheel of the vehicle (100) so that the vehicle (100) travels along a target trajectory (Rt) that avoids collision with the obstacle (OB) without leaving the driving lane (LA1).

[0017] To avoid a collision between the vehicle (100) and the obstacle (OB), a first steering control, which increases the rudder angle (θs), is executed. Following this first steering control, to prevent the vehicle (100) from leaving the driving lane (LA1), a second steering control, which decreases the rudder angle (θs), is executed.

[0018] In the execution of the collision avoidance control, the steering resistance is calculated based on the rudder angular velocity (dθs / dt), and damping control is applied to the steering wheel based on the calculated steering resistance.

[0019] The damping control is not executed during the execution of the first steering control, but is executed during the execution of the second steering control.

[0020] The procedure disclosed herein enables the computer of a driving support device (1) to perform processing, which, when the driving support device (1) detects an obstacle (OB) with a high probability of collision with its own vehicle (100) in the area in front of and to the front side of the vehicle (100), implements collision avoidance control to control the rudder angle (θs) of the steering wheel of the own vehicle (100) so that the own vehicle (100) travels along a target trajectory (Rt) that avoids collision with the obstacle (OB) without leaving the driving lane (LA1).

[0021] The process includes:

[0022] To avoid a collision between the vehicle (100) and the obstacle (OB), a first steering control, which increases the rudder angle (θs), is executed. Following this first steering control, to prevent the vehicle (100) from leaving the driving lane (LA1), a second steering control, which decreases the rudder angle (θs), is executed.

[0023] In the execution of the collision avoidance control, the steering resistance is calculated based on the rudder angular velocity (dθs / dt), and damping control is applied to the steering wheel based on the calculated steering resistance.

[0024] The damping control is not executed during the execution of the first steering control, but is executed during the execution of the second steering control.

[0025] Based on the above configuration, damping control, which imparts steering resistance, is not performed during the execution of the first steering control, but is performed during the execution of the second steering control. Therefore, in the first steering control, understeer angle due to damping torque can be reliably suppressed. Furthermore, in the second steering control, by imparting damping torque in the direction of canceling the self-calibrating torque (correcting torque), control overshoot caused by excessive rudder angle can be reliably suppressed.

[0026] In another embodiment of this disclosure,

[0027] The damping control unit (10, 60) initiates the damping control when the rudder angular velocity (dθs / dt) becomes above a predetermined threshold velocity during the execution of the second steering control.

[0028] According to this scheme, by initiating damping control after the rudder angular velocity (dθs / dt) reaches or exceeds a predetermined threshold speed, it is possible to reliably prevent the application of damping torque before the second steering control response. This effectively suppresses the deterioration of the responsiveness of the second steering control.

[0029] In the above description, in order to help understand the invention, reference numerals (drawing numerals) used in the embodiments are added in parentheses for the constituent elements of the invention corresponding to the embodiments, but the constituent elements of the invention are not limited to the embodiments specified by the reference numerals. Attached Figure Description

[0030] Figure 1 This is a schematic overall configuration diagram of the driving support device involved in this embodiment.

[0031] Figure 2 This is a schematic diagram illustrating the general operation of the collision avoidance control involved in this embodiment.

[0032] Figure 3 This is a control block diagram of the driving support ECU involved in this embodiment.

[0033] Figure 4 This is a timeline diagram illustrating the specific processing flow of the first steering control, the second steering control, and the damping control involved in this embodiment.

[0034] Figure 5 This is a flowchart illustrating the routine of the collision avoidance control process involved in this embodiment.

[0035] Figure 6This is a flowchart illustrating the routine of the damping control process involved in this embodiment.

[0036] Figure 7 This is a flowchart illustrating the routine for damping control in the modified example.

[0037] Figure 8 This is a schematic diagram illustrating the collision avoidance control of the comparative example.

[0038] Figure 9 This is a schematic diagram illustrating the collision avoidance control of the comparative example.

[0039] Label Explanation

[0040] 1… Driving support device, 10… Driving support ECU, 11A… Three-dimensional object information acquisition unit, 11B… Obstacle detection unit, 11C… Collision detection unit, 11D… Target trajectory setting unit, 12… Target rudder angle calculation unit, 13… FF control quantity calculation unit, 14… FB control quantity calculation unit, 15… Addition unit, 17… Subtraction unit, 19… Damping control quantity calculation unit, 20… Vehicle status acquisition device, 30… Surroundings recognition device, 60… Steering ECU, 61… Motor driver, 62… Steering motor, 63… Steering device, 64… Rudder angle sensor, 65… Steering torque sensor, 100… Vehicle itself, OB… Obstacle, LA1… Driving lane. Detailed Implementation

[0041] Hereinafter, with reference to the accompanying drawings, the driving support device, driving support method, and procedure according to this embodiment will be described. The same reference numerals are used for the same components, and their names and functions are also the same. Therefore, detailed descriptions of them will not be repeated.

[0042] [Overall Composition]

[0043] Figure 1 This is a schematic overall configuration diagram of the driving support device 1 according to this embodiment. Figure 1As shown, the driving support device 1 is mounted on vehicle 100. To distinguish it from other vehicles, vehicles 100 and below equipped with the driving support device 1 are also referred to as "their own vehicle". The driving support device 1 includes a driving support ECU 10, a drive power ECU 40, a braking ECU 50, and a steering ECU 60. Each ECU 10, 40, 50, and 60 has a microcomputer as its main component and is interconnected via a CAN (Controller Area Network) (not shown) to send and receive information. Furthermore, ECU is an abbreviation for Electronic Control Unit. The microcomputer includes a CPU, ROM, RAM, and an interface (INTERFACE: I / F), etc. The CPU performs various functions by executing commands (programs, routines) stored in the ROM. Several or all of ECUs 10, 40, 50, and 60 can also be integrated into a single ECU as a controller.

[0044] The driver support ECU 10 is a central control device that provides driver support and implements collision avoidance control in this embodiment. The driver support ECU 10 is connected to the vehicle status acquisition device 20 and the surrounding recognition device 30, and receives output signals and detection signals from these devices 20 and 30 at predetermined intervals.

[0045] The vehicle status acquisition device 20 is a sensor group that acquires the status of the vehicle 100. Specifically, the vehicle status acquisition device 20 includes a vehicle speed sensor 21, an accelerometer sensor 22, a brake sensor 23, an IMU (Inertial Measurement Unit) 24, etc.

[0046] Vehicle speed sensor 21 detects the travel speed (vehicle speed V) of vehicle 100. Vehicle speed sensor 21 may be a wheel speed sensor. Accelerator sensor 22 detects the amount of driver input to the accelerator pedal (not shown). Brake sensor 23 detects the amount of driver input to the brake pedal (not shown). IMU 24 detects the acceleration of vehicle 100 in the forward / backward, left / right, and up / down directions, as well as the angular velocities (yaw rate Yr) of vehicle 100 in the roll, pitch, and yaw directions.

[0047] The surrounding identification device 30 is a sensor group that acquires object information related to objects (targets) around the vehicle 100. Specifically, the surrounding identification device 30 includes a camera sensor 31, a radar sensor 32, an ultrasonic sensor 33, etc.

[0048] The camera sensor 31 is, for example, a stereo camera or a single-lens reflex camera; a digital camera with imaging elements such as CMOS or CCD can be used. The camera sensor 31 captures images of the area in front of and to the front and sides of the vehicle 100, and identifies road markings by processing the captured image data. Road markings include lane markings. Lane markings are lines placed on the road to distinguish vehicle traffic directions. Lane markings include solid lane markings and dashed lane markings. In this embodiment, the area between two adjacent lane markings extending on the roadway is defined as a lane. The camera sensor 31 calculates the shape of the lane based on the identified lane markings. Furthermore, based on the captured image data, the camera sensor calculates whether there are any three-dimensional objects in the area in front of and to the front and sides of the vehicle 100, the type of three-dimensional object, and the relative relationship between the vehicle 100 and the three-dimensional object. The type of three-dimensional object can be determined by parsing the image data using a well-known image matching method.

[0049] Radar sensor 32, for example, detects objects present in the area in front of and to the front side of vehicle 100. Radar sensor 32 includes millimeter-wave radar and / or lidar. Millimeter-wave radar radiates millimeter-wave radio waves (millimeter waves) and receives millimeter waves (reflected waves) reflected by objects present within the radiation range. Based on the phase difference between the emitted millimeter waves and the received reflected waves, the attenuation level of the reflected waves, and the time from the emission of the millimeter waves to the receipt of the reflected waves, millimeter-wave radar obtains the relative distance and relative speed between vehicle 100 and objects. Lidar sequentially scans and emits pulsed laser light with wavelengths shorter than millimeter waves in multiple directions and receives reflected light from objects, thereby obtaining the shape of objects detected in front of vehicle 100, the relative distance and relative speed between vehicle 100 and objects.

[0050] The ultrasonic sensor 33 transmits ultrasonic waves in pulses to a predetermined range around the vehicle 100 and receives reflected waves from three-dimensional objects. Based on the time from the transmission of the ultrasonic wave to its reception, the ultrasonic sensor 33 obtains object information, such as the distance between the point on the three-dimensional object where the transmitted ultrasonic wave is reflected (i.e., the reflection point) and the ultrasonic sensor 33.

[0051] The drive source ECU 40 is connected to the drive unit 41. The drive unit 41 generates driving force that is transmitted to the drive wheels of the vehicle 100. Examples of drive units 41 include electric motors and engines. The vehicle 100 can be any of the following: a motor vehicle, a hybrid electric vehicle (HEV), a plug-in hybrid electric vehicle (PHEV), a fuel cell electric vehicle (FCEV), or a battery electric vehicle (BEV). The drive source ECU 40 sets the required drive torque based on the accelerator pedal operation amount obtained from the accelerator sensor 22, and controls the operation of the drive unit 41 so that the drive unit 41 outputs the required drive torque.

[0052] The brake ECU 50 is connected to the brake actuator 51. The brake actuator 51 is located in a hydraulic circuit between a master cylinder (not shown) that pressurizes the working fluid according to the pressure applied to the brake pedal and the brake mechanism 52 located at each wheel. The brake mechanism 52 includes a brake disc 52a fixed to the wheel and a brake caliper 52b fixed to the vehicle body. Furthermore, the brake mechanism 52 is not limited to a disc brake, but may also be other braking mechanisms that apply braking force to the wheels of the vehicle 100, such as a drum brake.

[0053] The brake actuator 51 adjusts the hydraulic pressure supplied to the wheel cylinder built into the brake caliper 52b according to the instruction from the brake ECU 50, thereby actuating the wheel cylinder. This causes the brake actuator 51 to press the brake pads against the brake disc 52a, generating frictional braking force. Therefore, the brake ECU 50 can control the braking force of the vehicle 100 by controlling the brake actuator 51.

[0054] The steering ECU 60 is connected to the motor driver 61. The motor driver 61 is connected to the steering motor 62. The steering motor 62 is assembled into the steering system 63, which includes the steering wheel SW, steering shaft SF, etc. The steering system 63 can be either rack and pinion or steer-by-wire. The steering motor 62 generates steering torque using electricity supplied from the motor driver 61. This steering torque allows the left and right steering wheels of the vehicle 100 to be turned. That is, the steering motor 62 can change the rudder angle (steering wheel angle) of the vehicle 100.

[0055] The steering ECU 60 is connected to the steering angle sensor 64 and the steering torque sensor 65. The steering angle sensor 64 detects the rotation angle of the steering wheel SW or the steering shaft SF, i.e., the actual steering angle θs. The steering torque sensor 65 detects the rotational torque of the steering wheel SW or the steering shaft SF, i.e., the actual steering torque Tq. The actual steering angle θs and the actual steering torque Tq are defined, for example, as positive values ​​when steering the vehicle 100 in the left direction and negative values ​​when steering the vehicle 100 in the right direction.

[0056] The steering ECU 60 controls the drive of the steering motor 62 based on the actual steering angle θs detected by the steering angle sensor 64, the actual steering torque Tq detected by the steering torque sensor 65, and the vehicle speed V detected by the vehicle speed sensor 21. Through the drive of the steering motor 62, the steering ECU 60 can impart steering assistance torque to the steering device 63 to assist the driver's steering operations.

[0057] Furthermore, during collision avoidance control, when the steering ECU 60 receives a steering command from the driver support ECU 10, it drives the steering motor 62 via the motor driver 61 based on the target steering torque determined according to the steering command. Thus, the steering ECU 60 generates steering torque in a manner consistent with the target steering torque. This steering torque differs from the aforementioned steering assist torque; it is the torque imparted to the steering device 63 based on the steering command from the driver support ECU 10. Therefore, during collision avoidance control, the driver support ECU 10 can automatically change the rudder angle of the vehicle 100's steering wheels via the steering ECU 60 without driver intervention.

[0058] Collision Avoidance Control

[0059] Next, based on Figure 2 and Figure 3 This section provides a summary of the operation of collision avoidance control. It assumes that, for example... Figure 2 As shown, when vehicle 100 is traveling, for example, in lane LA1, which is a straight road, a situation arises where there is a three-dimensional object (landmark) or obstacle OB with a high probability of collision with vehicle 100. In this case, the driver support ECU 10 executes collision avoidance control to prevent vehicle 100 from colliding with obstacle OB. Collision avoidance control refers to the control of automatically steering the steering wheel of vehicle 100 to avoid collision with obstacle OB without leaving lane LA1. Here, automatic steering includes the concept of steering support that assists the driver's steering operation to prevent vehicle 100 from colliding with obstacle OB.

[0060] Specifically, as a collision avoidance control, after executing "first steering control" to avoid a collision with obstacle OB, the driving support ECU 10 executes "second steering control" to keep the vehicle 100 within the driving lane LA1. In the first steering control, "first steering increase steering" (refer to section S1) is performed, which increases the steering angle from, for example, a neutral position (a state where the steering angle is approximately 0). In the second steering control, "first steering return steering" (refer to section S2) is performed sequentially, which returns the steering angle increased by the first steering control to the neutral position; "second steering increase steering" (refer to section S3) is performed, which increases the steering angle from the neutral position in the opposite direction to the steering direction of the first steering control; and "second steering return steering" (refer to section S4) returns the steering angle back to the neutral position.

[0061] Figure 3 This is a control block diagram of the driver support ECU 10 that implements collision avoidance control. The driver support ECU 10 includes functional elements such as a three-dimensional object information acquisition unit 11A, an obstacle determination unit 11B, a collision determination unit 11C, a target trajectory setting unit 11D, a target rudder angle calculation unit 12, an FF control quantity calculation unit 13, an FB control quantity calculation unit 14, an addition unit 15, a subtraction unit 17, and a damping control quantity calculation unit 19. These functional elements are described as being integrated into the driver support ECU 10, but any part of them can also be set in another ECU independent of the driver support ECU 10. In addition, all or part of the functional elements of the driver support ECU 10 can also be set in an information processing device of a facility (such as a management center) that can communicate with its own vehicle 100.

[0062] The stereoscopic object information acquisition unit 11A is based on the left white line WL and right white line WR (see reference) sent from the surrounding recognition device 30. Figure 2 The system uses location information to identify the driving lane LA1, which is divided by the left white line WL and the right white line WR. Additionally, the object information acquisition unit 11A determines whether there are any three-dimensional objects in front of and to the front side of the vehicle 100 based on the object information sent from the surrounding recognition device 30. If an object is determined to be present, the object information acquisition unit 11A generates information related to all the identified three-dimensional objects. Specifically, the object information acquisition unit 11A uses the center of the front of the vehicle 100 as the origin and a coordinate system extending left, right, and forward from that origin to generate coordinate information for each three-dimensional object, including its position coordinates.

[0063] The obstacle determination unit 11B determines whether each three-dimensional object acquired by the three-dimensional object information acquisition unit 11A is an obstacle OB that may collide with its own vehicle 100. Specifically, the obstacle determination unit 11B calculates the turning radius of its own vehicle 100 based on the vehicle speed V detected by the vehicle speed sensor 21, the yaw rate Yr detected by the IMU 24, and the actual rudder angle θs detected by the rudder angle sensor 64, and calculates the trajectory of its own vehicle 100 based on this turning radius.

[0064] Furthermore, the obstacle determination unit 11B calculates the trajectory of each three-dimensional object based on its coordinate information. Based on the trajectory of its own vehicle 100 and the trajectories of each three-dimensional object, the obstacle determination unit 11B determines whether its own vehicle 100 is likely to collide with any three-dimensional object while maintaining its current driving state and the three-dimensional objects maintaining their current moving states. Additionally, when the three-dimensional object is stationary, the driver support ECU 10 performs this determination process based on the trajectory of its own vehicle 100 and the current position of the three-dimensional object. If the obstacle determination unit 11B determines that its own vehicle 100 is likely to collide with a three-dimensional object based on the determination result, it classifies that three-dimensional object as an obstacle OB.

[0065] When the obstacle determination unit 11B determines that the three-dimensional object is an obstacle OB, the collision determination unit 11C calculates the predicted time (Time To Collision, hereinafter referred to as "TTC") up to the collision between the vehicle 100 and the obstacle OB, based on the distance L from the vehicle 100 to the obstacle OB and the relative speed Vr of the vehicle 100 relative to the obstacle OB. TTC is an index value representing the probability of the vehicle 100 colliding with the obstacle OB. TTC can be obtained by dividing the distance L from the vehicle 100 to the obstacle OB by the relative speed Vr (TTC = L / Vr). If the TTC is below a predetermined collision determination threshold TTCth, the collision determination unit 11C determines that the probability of the vehicle 100 colliding with the obstacle OB is high.

[0066] When the collision determination unit 11C determines that the probability of the vehicle 100 colliding with the obstacle OB is high, the target track setting unit 11D calculates a track from which the vehicle 100 can avoid collision without interfering with the obstacle OB using a known method, and sets the calculated track as the target track Rt (refer to...). Figure 2(For example, see Japanese Patent Application Publication No. 2017-43262 and Japanese Patent Application Publication No. 2018-106230, etc.). In this case, the target track Rt is generated based on the object information of the obstacle OB and the positions of the white lines WL and WR on the left and right sides, within the avoidance space SP1 set on either the left or right side of the obstacle OB, and within a range that will not cause the vehicle 100 to deviate from the driving lane LA1.

[0067] Specifically, such as Figure 2 As shown, the target trajectory Rt is set within the first steering interval S1, which performs the first steering control to avoid a collision between vehicle 100 and obstacle OB, and the second to fourth steering intervals S2 to S4, which perform the second steering control to keep vehicle 100 within the driving lane LA1. In the first steering interval S1, the first steering increase steering is performed under the first steering control. In the second steering interval S2, the first steering return steering is performed under the second steering control. In the third steering interval S3, the second steering increase steering is performed under the second steering control. In the fourth steering interval S4, the second steering return steering is performed under the second steering control.

[0068] After the target trajectory Rt is set by the target trajectory setting unit 11D, the target rudder angle calculation unit 12 calculates the target rudder angle θt that can obtain the target yaw rate based on the current vehicle speed V of its own vehicle 100 and the target yaw rate required for its own vehicle 100 to travel along the target trajectory Rt. The target rudder angle calculation unit 12 sends the calculated target rudder angle θt to the FF control quantity calculation unit 13 and the subtraction unit 17.

[0069] The FF control quantity calculation unit 13 calculates the FF target steering torque T as the feedforward control quantity based on the target rudder angle θt. FF The FF control quantity calculation unit 13, for example, calculates the target FF steering torque T by referring to a pre-stored FF torque mapping (not shown) based on the target rudder angle θt. FF The torque mapping for FF is set so that as the target rudder angle θt increases, the target steering torque T of FF increases. FF Increase. In addition, the target steering torque T of FF... FF The calculation is not limited to using a mapping method; it can also be based on a computational formula. The FF control quantity calculation unit 13 will calculate the FF target steering torque T. FF Send to Addition Department 15.

[0070] The subtraction unit 17 calculates the deviation Δθ between the target rudder angle θt sent from the target rudder angle calculation unit 12 and the actual rudder angle θs detected by the rudder angle sensor 64. The subtraction unit 17 then sends the calculated deviation Δθ to the FB control quantity calculation unit 14.

[0071] The FB control quantity calculation unit 14 calculates the FB target steering torque T as the feedback control quantity based on the deviation Δθ. FB The FB control quantity calculation unit 14 calculates the target steering torque T using, for example, PID control, PI control, or P control that includes the deviation Δθ as a proportional term. FB The FB control quantity calculation unit 14 calculates the FB target steering torque T. FB Send to Addition Department 15.

[0072] The addition unit 15 processes the target steering torque T of the FF sent from the FF control quantity calculation unit 13. FF Adding the FB target steering torque T sent from the FB control quantity calculation unit 14 FB To calculate the target steering torque Tt (=T FF +T FB Additionally, the damping torque T is sent from the damping control quantity calculation unit 19 (described later) to the addition unit 15. DP When the adder 15 receives the damping torque T... DP At that time, by adding damping torque T to the target steering torque Tt DP To calculate the corrected target steering torque Tt*(=T FF +T FB +T DP The addition unit 15 sends a steering command containing information representing the target steering torque Tt or the modified target steering torque Tt* to the steering ECU 60.

[0073] When the steering ECU 60 receives a steering command from the driving support ECU 10, it converts the information contained in the steering command—the target steering torque Tt or the modified target steering torque Tt*—into a target current and controls the operation of the motor driver 61 so that the target current flows into the steering motor 62. A current sensor (not shown) is provided in the motor driver 61 to detect the current flowing into the steering motor 62. The steering ECU 60 controls the duty cycle of the switching element (not shown) of the motor driver 61 so that the actual current detected by the current sensor is equal to the target current. Thus, the steering motor 62 outputs the target steering torque Tt or the modified target steering torque Tt*, and the steering wheels of the vehicle 100 are turned. As a result, automatic steering is achieved, enabling the vehicle 100 to travel along the target track Rt while avoiding collisions with obstacles OB and preventing the vehicle 100 from leaving the driving lane LA1.

[0074] The damping control calculation unit 19 calculates the steering resistance, i.e., the damping torque T, which is in the opposite direction to the target steering torque Tt. DP Here, "opposite direction" means that if the target steering torque Tt is positive (left turn direction), then the damping torque T DPIf the target steering torque Tt is negative (right turn direction), then the damping torque T becomes negative. DP It becomes a positive value (left turn direction). The damping control quantity calculation unit 19 calculates the damping torque T, for example, based on the rudder angular velocity dθs / dt and referring to a pre-stored damping torque map (not shown). DP Preferably, the damping torque mapping is set such that as the rudder angular velocity dθs / dt increases, the damping torque T... DP Increase. The rudder angular velocity dθs / dt can be obtained by differentiating the actual rudder angle θs detected by the rudder angle sensor 64 over time. Furthermore, the damping torque T... DP Operations are not limited to using mapping methods; they can also be performed based on computational formulas.

[0075] The damping control quantity calculation unit 19 calculates the damping torque T DP Send to the adder 15. The adder 15, upon receiving the damping torque T... DP At that time, the damping torque T is added to the target steering torque Tt. DP The corrected target steering torque Tt* is obtained and sent to the steering ECU 60. The steering ECU 60 controls the operation of the motor driver 61 so that the corrected target steering torque Tt* is output from the steering motor 62. This achieves damping control by applying damping torque in collision avoidance control. When applying damping torque, an upper limit can be set on the amount of change in damping torque per unit time to suppress abrupt torque fluctuations.

[0076] In this embodiment, the damping control quantity calculation unit 19 operates such that it does not calculate the damping torque T during the execution of the first steering control. DP The damping torque T is calculated only during the execution of the second steering control. DP And send it to the addition unit 15. That is, it is configured to impart damping torque T only during the execution of the second steering control. DP .

[0077] Here, we explain the reason for applying damping torque only to the second steering control. Figure 8 This diagram illustrates the situation where no damping torque (damping torque: Off) is applied to either the first or second steering control in collision avoidance control. Figure 9 This diagram illustrates the application of damping torque (damping torque: On) to both the first and second steering controls.

[0078] like Figure 8As shown, when no damping torque is applied to either the first or second steering control, the self-calibrating torque generated in the steering wheel of vehicle 100 during the execution of the first steering control is added to the first steering return steering (section S2) and the second steering increase steering (section S3) of the second steering control. This causes the steering increase steering (section S3) of the second steering control to become an overshoot (see Figure A), resulting in the problem of vehicle 100's trajectory heading towards obstacle OB. Furthermore, in the second steering return steering (section S4) of the second steering control, the self-calibrating torque generated in the steering wheel during the execution of the second steering increase steering (section S3) is also added, causing overshoot (see Figure B).

[0079] On the other hand, such as Figure 9 As shown, when damping torque is applied to both the first and second steering controls, overshoot of the second steering control can be suppressed. However, if damping torque is also applied to the first steering control, the rudder angle of the first steering increase (interval S1) becomes insufficient (see Figure C). As a result, the problem arises that the vehicle 100 cannot reliably avoid a collision with the obstacle OB.

[0080] That is, if damping torque is not applied to the first steering control but only to the second steering control, the insufficient steering angle of the first steering control, which is used to avoid a collision with the obstacle OB, is suppressed, and excessive (overshoot) steering angle of the second steering control, which is used to keep the vehicle 100 within the driving lane LA1, is prevented. The driving support ECU 10 of this disclosure applies damping torque only to the second steering control for this reason.

[0081] The following is based on Figure 4 The timeline shown illustrates the specific processing flow of the first steering control, the second steering control, and the damping control.

[0082] exist Figure 4 In (A) the rudder angle, the solid line shows the target rudder angle of this disclosure, the dashed line shows the actual rudder angle of this disclosure, and the dashed line shows the actual rudder angle of the comparative example without applied damping torque. Additionally, in Figure 4 In (B) rudder angular velocity, the solid line shows the target rudder angular velocity of this disclosure, the dashed line shows the actual rudder angular velocity of this disclosure, and the dashed line shows the actual rudder angular velocity of the comparative example without applied damping torque. Additionally, in Figure 4 In the steering torque (C), the solid line represents the target steering torque of the present disclosure (FF), and the dashed line represents the damping torque of the present disclosure. Furthermore, in Figure 4In the example shown, vehicle 100 avoids collision with obstacle OB by turning left, but if it avoids collision by turning right, only the rudder angle, rudder angular velocity, and steering torque become opposite, so the following explanation is omitted.

[0083] Assuming in Figure 4 At time t1, the TTC drops below the predetermined collision determination threshold TTCth. When the TTC falls below the collision determination threshold TTCth, the driver support ECU 10 initiates first steering control from time t1 to avoid a collision between the vehicle 100 and the obstacle OB. Specifically, the driver support ECU 10 initiates first steering increase steering (refer to interval S1) by increasing the steering angle from the neutral position (approximately 0°). Damping control remains OFF (inactive) until the first steering control ends at time t2. That is, damping control is not performed during the execution of the first steering control. This prevents insufficient steering angle during the first steering control.

[0084] After the first steering control ends at time t2 due to the fulfillment of a predetermined termination condition, the driving support ECU 10 begins the second steering control to keep the vehicle 100 within the driving lane LA1. The first steering control is, for example, based on the target steering torque T according to FF. FF The control end point is set at the point where the rudder angle value begins to gradually decrease from its maximum value, obtained from the curve of the rudder angle. After the first steering control ends, the driving support ECU 10 executes the first rudder return steering (refer to interval S2) to return the rudder angle to the neutral position starting from time t2. In addition, at the same time as the second steering control begins at time t2, the driving support ECU 10 switches the damping control from OFF (inactive) to ON (active).

[0085] After the first steering return to normal operation ends at time t3, the driving support ECU 10 performs a second steering increase operation (refer to interval S3) during the period from time t3 to time t4, which increases the steering angle from the neutral position to the direction opposite to the steering direction of the first steering control. When the actual steering angle velocity increases due to the second steering return operation starting from time t2, a damping torque corresponding to the increase in actual steering angle velocity is applied to the first steering return operation (refer to interval S2) and the second steering increase operation (refer to interval S3). That is, the damping torque is applied in the direction that counteracts the self-calibrating torque generated on the steering wheel during the execution of the first steering control. As a result, the excessive steering angle of the second steering increase operation that occurred in the comparative example (refer to Figure A) can be prevented, and overshoot can be effectively suppressed.

[0086] After the second steering increase control ends at time t4, the driving support ECU 10 performs a second steering return control to return the rudder angle to the neutral position during the period from time t4 to time t5 (refer to interval S4). When the actual rudder angle velocity increases due to the second steering return control starting from time t4, a damping torque corresponding to the increase in actual rudder angle velocity is applied to the second steering return control. That is, the damping torque is applied in the direction of counteracting the self-calibrating torque generated on the steering wheel during the execution of the first steering return control and the second steering increase control (refer to intervals S2-3). As a result, the excessive rudder angle of the second steering return control that occurred in the comparative example (see Figure B) can be prevented, and overshoot can be effectively suppressed.

[0087] When the second steering control ends at time t5 due to the fulfillment of the predetermined termination condition, the driver support ECU 10 terminates the collision avoidance control by switching the damping control from ON (active) to OFF (inactive). The second steering control can end, for example, when the yaw angle of the vehicle 100 becomes approximately parallel to the driving lane LA1 (white lines WL, WR) or when the actual steering angle θs is within the desired angle range.

[0088] Next, based on Figure 5 The flowchart shown illustrates the routine of collision avoidance control performed by the driver support ECU 10. The driver support ECU 10 repeatedly executes this routine at predetermined intervals during the operation of the vehicle 100. Figure 5 The processing after step S100.

[0089] In step S100, the driving support ECU10 identifies the driving lane LA1 divided by the left white line WL and the right white line WR based on the position information of the left white line WL and the right white line WR sent from the surrounding recognition device 30.

[0090] Next, in step S105, the driving support ECU 10 determines whether there are any three-dimensional objects in the area in front of and to the front side of its own vehicle 100 based on the object information sent from the surrounding recognition device 30. If there are three-dimensional objects (yes), the driving support ECU 10 proceeds to step S110. On the other hand, if there are no three-dimensional objects (no), the driving support ECU 10 temporarily ends the current routine (returns).

[0091] In step S110, the driving support ECU 10 acquires the position information of the three-dimensional object. Next, in step S115, the driving support ECU 10 determines whether the three-dimensional object is an obstacle OB that may collide with its own vehicle 100. If the driving support ECU 10 determines that the three-dimensional object is an obstacle OB, then if the three-dimensional object is determined to be an obstacle OB (yes), the driving support ECU 10 proceeds to step S120. On the other hand, if the three-dimensional object is determined not to be an obstacle OB (no), the driving support ECU 10 temporarily terminates this routine (returns).

[0092] In step S120, the driving support ECU 10 calculates the TTC. Next, in step S125, the driving support ECU 10 determines whether the TTC is below a predetermined collision determination threshold TTCth. If the TTC is below the collision determination threshold TTCth (yes), the driving support ECU 10 proceeds to step S130. On the other hand, if the TTC is not below the collision determination threshold TTCth (no), the driving support ECU 10 temporarily terminates the current routine (returns).

[0093] In step S130, the driving support ECU 10 determines that the probability of its own vehicle 100 colliding with the obstacle OB is high. Next, in step S140, the driving support ECU 10 sets a target trajectory Rt that allows its own vehicle 100 to avoid collision with the obstacle OB without leaving the driving lane LA1, and proceeds to step S150. Furthermore, although detailed explanations are omitted, in the absence of the aforementioned avoidance space SP1 (refer to...), Figure 2 If the target trajectory Rt cannot be set, the driving support ECU10 can perform collision avoidance control through braking control.

[0094] In step S150, the driving support ECU 10 initiates first steering control, which involves increasing the rudder angle of the vehicle 100 to allow it to travel along the target trajectory Rt while avoiding the obstacle OB. In step S155, once the termination condition of the first steering control is met, the driving support ECU 10 proceeds to step S160.

[0095] In step S160, the driving support ECU 10 begins second steering control, which involves increasing or decreasing the rudder angle of the vehicle 100 to keep it within the driving lane LA1 while traveling along the target trajectory Rt. Specifically, this involves sequentially performing a first steering return steering, which returns the rudder angle increased by the first steering control to the neutral position; a second steering increase steering, which increases the rudder angle from the neutral position to the opposite direction of the first steering control; and a second steering return steering, which returns the rudder angle to the neutral position again. In step S165, when the termination condition of the second steering control is met, the driving support ECU 10 temporarily terminates the current routine (returns).

[0096] Next, based on Figure 6 The flowchart shown illustrates the routine for damping control processing performed by the driving support ECU 10. During vehicle 100 operation, the driving support ECU 10 and... Figure 5 The example shown is executed repeatedly in parallel. Figure 6 The damping control is shown. Additionally, in Figure 6 At the start of the routine shown, the flag F for performing damping control is set to OFF (F=0).

[0097] In step S200, the driving support ECU 10 determines whether the second steering control has started. If the second steering control has started (yes), the driving support ECU 10 proceeds to step S210. On the other hand, if the second steering control has not started (no), the driving support ECU 10 temporarily terminates the current routine (returns).

[0098] In step S210, the driving support ECU10 sets the flag F for enabling damping control to ON (F=1).

[0099] In step S230, the driving support ECU 10 calculates the damping torque T based on the rudder angular velocity dθs / dt obtained by time differentiation of the actual rudder angle θs detected by the rudder angle sensor 64. DP Next, in step S240, the driving support ECU10 applies a damping torque T to the target steering torque Tt. DP The corrected target steering torque Tt* is then sent to the steering ECU 60. That is, control is performed so that the steering motor 62 outputs the corrected target steering torque Tt*.

[0100] In step S250, the driving support ECU 10 determines whether the second steering control has ended. If the second steering control has ended (yes), the driving support ECU 10 proceeds to step S260. On the other hand, if the second steering control has not ended (no), the driving support ECU 10 returns to the determination process in step S220.

[0101] In step S260, the driving support ECU 10 sets the damping control enable flag F to OFF (F=0), ending damping control (returning). Thereafter, until the vehicle 100 comes to a stop, the driving support ECU 10 and... Figure 5 The routine shown executes each of the above steps S200 to S260 in parallel and repeatedly.

[0102] As detailed above, in this embodiment, when the driving support ECU 10 detects an obstacle OB with a high probability of collision with the vehicle 100 in the area in front of and to the front side of the vehicle 100, it sets a target trajectory Rt that allows the vehicle 100 to avoid collision with the obstacle OB without leaving the driving lane LA1, and implements collision avoidance control by controlling the rudder angle of the steering wheel of the vehicle 100 so that the vehicle 100 travels along the target trajectory Rt. As automatic steering, the driving support ECU 10 sequentially performs a first steering control that increases the rudder angle to avoid collision between the vehicle 100 and the obstacle OB, and a second steering control that includes reducing the rudder angle to prevent the vehicle 100 from leaving the driving lane LA1. In addition, during the execution of automatic steering, the driving support ECU 10 calculates the damping torque T based on the rudder angle velocity dθs / dt. DP Furthermore, the calculated damping torque T is assigned to the target steering torque Tt. DP Damping control. At this time, the driving support ECU10 is configured such that damping control is not performed during the execution of the first steering control, but only during the execution of the second steering control.

[0103] Therefore, in the first steering control, insufficient rudder angle due to the application of damping torque can be reliably suppressed. That is, the collision between the vehicle 100 and obstacle OB due to insufficient rudder angle in the first steering control can be effectively prevented. Furthermore, in the second steering control, by applying damping torque in the direction that cancels out the self-calibrating torque, overshoot caused by excessive rudder angle can be reliably suppressed. That is, the deviation of the vehicle 100 from its track towards obstacle OB due to overshoot in the second steering control can be effectively prevented. In summary, according to this embodiment, it is possible to achieve both the suppression of insufficient rudder angle in the first steering control to avoid collision with obstacle OB and the suppression of excessive rudder angle in the second steering control to keep the vehicle 100 within the driving lane LA1.

[0104] [other]

[0105] The driving support device, driving support method and procedure involved in this embodiment have been described above, but this disclosure is not limited to the above embodiment and various modifications can be made without departing from the purpose of this disclosure.

[0106] [Variation Example]

[0107] For example, damping control can also be configured to begin after the second steering control has started, when the rudder angular velocity dθs / dt reaches a predetermined threshold velocity. A specific processing routine is shown below. Figure 7 The flowchart. Figure 7 The processes shown in the routine, except for step S220, become the same as... Figure 6 The various processes are basically the same, so their descriptions are omitted.

[0108] like Figure 7 As shown, after the driving support ECU 10 sets the flag F for enabling damping control to ON (F=1) in step S210, it determines in step S220 whether the rudder angle velocity dθs / dt has reached a predetermined threshold speed. If yes, the driving support ECU 10 proceeds to step S230. If no, the driving support ECU 10 returns to the determination process in step S220. In this way, by initiating damping control after the rudder angle velocity dθs / dt has reached or exceeded the predetermined threshold speed, it is possible to reliably prevent the application of damping torque before the second steering control response, and effectively suppress the deterioration of the responsiveness of the second steering control.

Claims

1. A driving assistance device that, when an obstacle with a high probability of collision with its own vehicle is detected in the area in front of and to the front side of the vehicle, implements collision avoidance control by controlling the rudder angle of the steering wheel of the own vehicle so that the own vehicle travels along a target trajectory that avoids collision with the obstacle without leaving the driving lane, wherein... The driving support device includes: To avoid a collision between the vehicle and the obstacle, the steering control unit performs a first steering control, which increases the rudder angle. After performing the first steering control, to prevent the vehicle from leaving the driving lane, it performs a second steering control, which includes a second steering control, which decreases the rudder angle. and The damping control unit performs damping control during the execution of the collision avoidance control, calculating the steering resistance based on the rudder angle velocity and applying the calculated steering resistance to the steering wheel. The steering control unit is configured such that, in the second steering control, it sequentially performs a first steering return to steering, which returns the rudder angle increased by the first steering control to the neutral position; a second steering increase to steering, which increases the rudder angle from the neutral position in the direction opposite to the steering direction of the first steering control; and a second steering return to steering, which returns the steering to the neutral position again. The damping control unit The damping control is not executed during the execution of the first steering control. If the second steering control begins, the execution of the damping control begins during the period of the first rudder turn returning to steering. If the second steering control ends, the execution of the damping control ends.

2. A driving assistance method, wherein, when an obstacle with a high probability of collision with the vehicle is detected in the area in front of and to the front side of the vehicle, collision avoidance control is implemented to control the rudder angle of the vehicle's steering wheel so that the vehicle travels along a target trajectory that avoids collision with the obstacle without leaving the driving lane, wherein, To avoid a collision between the vehicle and the obstacle, a first steering control, which increases the rudder angle, is executed. Following this first steering control, to prevent the vehicle from leaving the driving lane, a second steering control, which decreases the rudder angle, is executed. In the second steering control, the following steps are performed sequentially: a first steering return to the neutral position by returning the rudder angle increased by the first steering control; a second steering increase to the neutral position by increasing the rudder angle from the neutral position in the opposite direction to the steering direction of the first steering control; and a second steering return to the neutral position again. In the execution of the collision avoidance control, damping control is performed based on the rudder angle velocity to calculate the steering resistance and apply the calculated steering resistance to the steering wheel. The damping control is not executed during the execution of the first steering control. If the second steering control begins, the execution of the damping control begins during the period of the first rudder turn returning to steering. If the second steering control ends, the execution of the damping control ends.

3. A program product comprising a program that causes a computer of a driving support device to perform processing, wherein the driving support device, upon detecting an obstacle with a high probability of collision in the area in front of and to the front side of its own vehicle, implements collision avoidance control to control the rudder angle of the steering wheel of its own vehicle so that the own vehicle travels along a target trajectory that avoids collision with the obstacle without leaving the driving lane, wherein... The process includes: To avoid a collision between the vehicle and the obstacle, a first steering control, which increases the rudder angle, is executed. Following this first steering control, to prevent the vehicle from leaving the driving lane, a second steering control, which decreases the rudder angle, is executed. In the second steering control, the following steps are performed sequentially: a first steering return to the neutral position by returning the rudder angle increased by the first steering control; a second steering increase to the neutral position by increasing the rudder angle from the neutral position in the opposite direction to the steering direction of the first steering control; and a second steering return to the neutral position again. In the execution of the collision avoidance control, damping control is performed based on the rudder angle velocity to calculate the steering resistance and apply the calculated steering resistance to the steering wheel. The damping control is not executed during the execution of the first steering control. If the second steering control begins, the execution of the damping control begins during the period of the first rudder turn returning to steering. If the second steering control ends, the execution of the damping control ends.

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