Driving assistance device, driving assistance method, and program

Abstract

This relates to driving assistance devices, methods, and procedures. A driving assistance device (1) that implements collision avoidance control by controlling the steering angle (θs) of its own vehicle (100) to make the vehicle travel along a target trajectory (Rt) that avoids collisions with obstacles (OB) comprises: a target steering torque setting unit (10) that sets the target steering angle (θt) required for the vehicle to travel along the target trajectory and sets a target steering torque (Tt) that makes the steering angle match the target steering angle; and a counteracting torque setting unit (17) that sets a torque to eliminate the conflict between the driver's steering torque (Tdr) and the steering assist torque (Tt) set based on the driver's steering torque. AS The total steering torque (T) obtained by summing them up SUM The offsetting torque (T) CA The steering control unit (10, 60) performs steering control based on the torque control amount obtained by adding the target steering torque and the counteracting torque to control the rudder angle. This improves the rudder angle following performance of the automatic steering.

Description

Technical Field

[0001] This disclosure relates to driving assistance devices, driving assistance methods and procedures, and in particular to collision avoidance control technology for avoiding collisions between one's own vehicle and obstacles. Background Technology

[0002] For example, Patent Document 1 discloses the following technology: when autopilot (steering), the gain of the assist torque for assisting the driver to steer is set to be smaller than that when manual steering is used; when the driver's steering intervention is detected, the autopilot is switched to manual steering by gradually increasing the gain of the assist torque and gradually decreasing the gain of the autopilot torque.

[0003] Existing technical documents

[0004] Patent Document 1: Japanese Patent Application Publication No. 2004-256076 Summary of the Invention

[0005] As a driving assistance device installed in a vehicle, a collision avoidance control device is known that automatically controls the vehicle's steering angle when a high probability of collision is detected in front of the vehicle to avoid a collision with the obstacle. The collision avoidance control performs steering control to avoid a collision with the obstacle, followed by steering control to prevent the vehicle from deviating from its driving lane. In this collision avoidance control, improving the steering angle following performance (trackability) of the automatic steering is crucial to achieving both obstacle avoidance and lane departure prevention.

[0006] However, during collision avoidance control, if the driver is inattentively holding the steering wheel (steering), the steering torque generated by the driver's steering and the corresponding auxiliary torque will act in the opposite direction to the autopilot's control torque. When this reverse torque acts on the control torque, the following problems occur: the autopilot's rudder angle tracking is reduced, resulting in insufficient rudder angle, etc.

[0007] This disclosure is made to solve the aforementioned problems. Specifically, one of the objectives of this disclosure is to effectively improve the rudder angle following performance of autopilot based on collision avoidance control.

[0008] The device disclosed herein is a driving assistance 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 side of the vehicle (100), controls the steering angle (θs) of the vehicle (100) so that the vehicle (100) travels along a target trajectory (Rt) that avoids collision with the obstacle (OB) without deviating from the driving lane (LA1). The device includes:

[0009] The target steering torque setting unit (10) sets the target rudder angle (θt) required for the vehicle (100) to travel along the target track (Rt), and sets the target steering torque (Tt) that makes the rudder angle (θs) of the vehicle (100) consistent with the target rudder angle (θt) when no driver steering torque (Tdr) is generated as the driver of the vehicle (100) performs steering or steering operations on the steering wheel (SW);

[0010] The offset torque setting unit (17) sets the offset torque (T) CA ), to offset torque (T) CA This is to eliminate the difference between the pilot's steering torque (Tdr) and the steering assist torque (T) set based on that pilot's steering torque (Tdr). AS The total steering torque (T) obtained by summing them up SUM Torque in the direction of ) and

[0011] The steering control unit (10, 60) executes based on the target steering torque (Tt) and the canceling torque (T) CA The torque control quantity obtained by adding the two values ​​is used to control the steering angle (θs) of the vehicle (100).

[0012] The method disclosed herein is a driving assistance method for collision avoidance control that, when an obstacle (OB) with a high probability of collision is detected in the area in front of and to the side of the vehicle (100), controls the steering angle (θs) of the vehicle (100) so that the vehicle (100) travels along a target trajectory (Rt) that avoids collision with the obstacle (OB) without deviating from the driving lane (LA1). The method includes:

[0013] Set a target rudder angle (θt) required for the vehicle (100) to travel along the target trajectory (Rt), and set a target steering torque (Tt) that makes the rudder angle (θs) of the vehicle (100) match the target rudder angle (θt) without generating a driver steering torque (Tdr) generated by the driver of the vehicle (100) performing steering or steering operations on the steering wheel (SW);

[0014] Set the offset torque (T) CA ), to offset torque (T) CA This is to eliminate the difference between the pilot's steering torque (Tdr) and the steering assist torque (T) set based on that pilot's steering torque (Tdr). AS The total steering torque (T) obtained by summing them up SUM Torque in the direction of ) and

[0015] Execution is based on the target steering torque (Tt) and the counteracting torque (T) CA The torque control quantity obtained by adding the two values ​​is used to control the steering angle (θs) of the vehicle (100).

[0016] The procedure disclosed herein enables the computer of a driving assistance device (1) to perform the following processing: when the driving assistance 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 side of its own vehicle (100), it performs collision avoidance control by controlling the steering angle (θs) of its own vehicle (100) so that its own vehicle (100) travels along a target trajectory (Rt) that avoids collision with the obstacle (OB) without deviating from the driving lane (LA1), the processing including:

[0017] Set a target rudder angle (θt) required for the vehicle (100) to travel along the target trajectory (Rt), and set a target steering torque (Tt) that makes the rudder angle (θs) of the vehicle (100) match the target rudder angle (θt) without generating a driver steering torque (Tdr) generated by the driver of the vehicle (100) performing steering or steering operations on the steering wheel (SW);

[0018] Set the offset torque (T) CA ), to offset torque (T) CA This is to eliminate the difference between the pilot's steering torque (Tdr) and the steering assist torque (T) set based on that pilot's steering torque (Tdr). AS The total steering torque (T) obtained by summing them up SUM Torque in the direction of ) and

[0019] Execution is based on the target steering torque (Tt) and the counteracting torque (T) CA The torque control quantity obtained by adding the two values ​​is used to control the steering angle (θs) of the vehicle (100).

[0020] Based on the above configuration, during automatic steering, the driver assistance ECU 10 applies a torque to eliminate the driver's steering torque (Tdr) generated by the driver's steering or steering operations, and the auxiliary torque (T) generated based on the driver's steering torque (Tdr). AS The total torque (T) of the driver is obtained by summing them up. SUM The offsetting torque (T) CA Therefore, during automatic steering, the pilot calculates the total torque (T). SUM The insufficiency of the actual rudder angle (θs) relative to the target rudder angle (θt) caused by the rudder angle is suppressed, thereby improving the rudder angle following performance.

[0021] In another technical solution disclosed herein,

[0022] The torque offset setting unit (17) includes:

[0023] The basic offset torque setting unit (17A) is set to completely eliminate the total steering torque (T). SUM The basic offset torque (T) CA1 );as well as

[0024] The gain setting unit (17B) is configured to provide a cancellation gain (K) corresponding to the magnitude of the driver's steering torque (Tdr).

[0025] By adjusting the basic offset torque (T) CA1 The cancelling torque (T) is set by multiplying the cancelling gain (K). CA ).

[0026] According to this technical solution, an optimal counteracting torque (T) corresponding to the magnitude of the pilot's steering torque (Tdr) can be applied. CA ).

[0027] In another technical solution disclosed herein,

[0028] The gain setting unit (17B) sets the cancellation gain (K) to a smaller value as the driver's steering torque (Tdr) increases.

[0029] According to this technical solution, it is possible to effectively prevent the driver's steering operation from being hindered when the driver has the intention to perform steering operations.

[0030] In another technical solution disclosed herein,

[0031] The gain setting unit (17B) sets the cancellation gain (K) to 0 if the state in which the driver's steering torque (Tdr) is above a predetermined threshold torque continues for a predetermined threshold time or more.

[0032] According to this technical solution, it is possible to reliably prevent the driver's steering operations from being hindered when the driver clearly has the intention to perform steering operations.

[0033] In another technical solution disclosed herein,

[0034] The gain setting unit (17B) sets the cancellation gain (K) to a smaller value as the deviation (ΔT) between the target steering torque and the driver's steering torque (Tdr) increases, and sets the cancellation gain (K) to 0 when the deviation (ΔT) exceeds a predetermined threshold.

[0035] According to this technical solution, the optimal counteracting torque (T) can be applied in accordance with the strength (degree) of the driver's steering intention. CA ).

[0036] The gain setting unit (17B) also sets the offset gain (K) to 0 if the deviation amount (ΔT) remains below the threshold for a predetermined threshold time or longer.

[0037] According to this technical solution, once the driver's intention to steer is clear, it can effectively prevent the driver's steering operation from being hindered.

[0038] The gain setting unit (17B) sets the cancellation gain (K) to 1 when the driver's steering torque (Tdr) increases or decreases within a predetermined torque range.

[0039] According to this technical solution, even when the driver is inattentively holding the steering wheel (SW), by setting the cancellation gain (K) to 1, that is, applying a method to completely eliminate the total steering torque (T), it is possible to achieve this. SUM The basic offset torque (T) CA1 This reliably improves the rudder angle tracking performance of autopilot.

[0040] In the above description, in order to help understand the invention, the constituent elements of the invention corresponding to the embodiments are added with reference numerals used in the embodiments in parentheses, but the constituent elements of the invention are not limited to the embodiments specified by the reference numerals. Attached Figure Description

[0041] Figure 1 This is a schematic overall configuration diagram of the driving assistance device involved in this embodiment.

[0042] Figure 2 This is a schematic diagram illustrating the general operation of the collision avoidance control involved in this embodiment.

[0043] Figure 3 This is a control block diagram of the driving assistance ECU involved in this embodiment.

[0044] Figure 4 This is a schematic diagram illustrating the application of a counteracting torque during the execution of collision avoidance control.

[0045] Figure 5 This is a schematic diagram illustrating a comparative example in which no counteracting torque is applied during the execution of collision avoidance control.

[0046] Figure 6 This is a schematic diagram illustrating an example of gain setting mapping.

[0047] Figure 7 This is a flowchart illustrating the routine of the collision avoidance control process involved in this embodiment.

[0048] Figure 8 This is a flowchart illustrating the routine of the torque-counteracting control process involved in this embodiment.

[0049] Figure 9 This is a schematic diagram illustrating variation 1.

[0050] Figure 10 This is a schematic diagram illustrating variation 2.

[0051] Figure 11 This is a schematic diagram illustrating variation 4. Detailed Implementation

[0052] Hereinafter, with reference to the accompanying drawings, the driving assistance device, driving assistance method, and procedure according to this embodiment will be described. The same reference numerals are assigned to the same components, and their names and functions are also the same. Therefore, detailed descriptions of them will not be repeated.

[0053] [Overall Composition]

[0054] Figure 1 This is a schematic overall configuration diagram of the driving assistance device 1 according to this embodiment. Figure 1As shown, the driver assistance device 1 is mounted on vehicle 100. To distinguish it from other vehicles, vehicle 100 equipped with driver assistance device 1 will be referred to as "its own vehicle" below. Driver assistance device 1 includes a driver assistance 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 can be interconnected via a CAN (Controller Area Network) (not shown). Furthermore, ECU is an abbreviation for Electronic Control Unit. The microcomputer includes a CPU, ROM, RAM, and interfaces (I / F), etc., and various functions are implemented by the CPU executing instructions (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.

[0055] The driver assistance ECU 10 is a central control device that provides driver assistance; in this embodiment, it implements collision avoidance control. The driver assistance 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.

[0056] The vehicle status acquisition device 20 is a type of sensor that acquires the status of the vehicle 100. Specifically, the vehicle status acquisition device 20 includes a vehicle speed sensor 21, an acceleration (throttle) sensor 22, a braking (brake) sensor 23, and an IMU (Inertial Measurement Unit) 24.

[0057] Vehicle speed sensor 21 detects the travel speed (vehicle speed V) of vehicle 100. Vehicle speed sensor 21 can also be a wheel speed sensor. Acceleration 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.

[0058] The surrounding recognition device 30 is a type of sensor that acquires target information related to targets around the vehicle 100. Specifically, the surrounding recognition device 30 includes a camera sensor 31, a radar sensor 32, an ultrasonic sensor 33, etc.

[0059] The camera sensor 31 is, for example, a stereo camera and / or a monocular camera, and can be a digital camera with imaging elements such as CMOS and CCD. The camera sensor 31 captures images of the area in front of and to the sides of the vehicle 100, and identifies road markings by processing the captured image data. Road markings include lane markings. Lane markings are lines marked on the road to delineate the direction of vehicle traffic. 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 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 pattern matching method.

[0060] Radar sensor 32 detects targets, for example, located in areas in front of and to the sides of vehicle 100. Radar sensor 32 includes millimeter-wave radar and / or lidar. Millimeter-wave radar emits millimeter-wave radio waves and receives millimeter waves reflected by targets within its emission range. Based on the phase difference between the emitted and received millimeter waves, the attenuation level of the reflected waves, and the time from emission to reception, millimeter-wave radar obtains the relative distance and speed between vehicle 100 and the target. Lidar sequentially scans pulsed laser light with wavelengths shorter than millimeter waves in multiple directions and receives reflected light from targets, thereby obtaining the shape of targets detected in front of vehicle 100, the relative distance and speed between vehicle 100 and the target.

[0061] 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 to the reception of the ultrasonic waves, the ultrasonic sensor 33 obtains target information such as the reflection point and the distance from the ultrasonic sensor 33, where the reflection point is a point on the three-dimensional object that reflects the transmitted ultrasonic waves.

[0062] 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: engine vehicle, hybrid electric vehicle (HEV), plug-in hybrid electric vehicle (PHEV), fuel cell electric vehicle (FCEV), and battery electric vehicle (BEV). Based on the accelerator pedal operation amount obtained by the acceleration sensor 22, the drive source ECU 40 sets the driver-requested drive torque and controls the operation of the drive unit 41 so that the drive unit 41 outputs the driver-requested drive torque.

[0063] 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 hydraulic oil using the force of 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 a drum brake or other braking mechanism that applies braking force to the wheels of the vehicle 100.

[0064] According to instructions from the brake ECU 50, the brake actuator 51 adjusts the hydraulic pressure supplied to the wheel cylinder built into the brake caliper 52b, 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.

[0065] 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 a rack and pinion type or a steer-by-wire type. The steering motor 62 generates steering torque using electricity supplied from the motor driver 61. This steering torque enables the left and right steering wheels of the vehicle 100 to turn. That is, the steering motor 62 can change the rudder angle (steering wheel angle) of the vehicle 100.

[0066] 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 driver's steering torque Tdr. Here, the driver's steering torque Tdr is a concept that includes both the steering torque generated when the driver rotates the steering wheel SW and the steering torque generated when the driver holds the steering wheel SW (holding the steering wheel). The actual steering angle θs and the driver's steering torque Tdr are positive, for example, when the steering wheel SW is rotated to the left from a predetermined reference position (neutral position), and negative when the steering wheel SW is rotated to the right from the predetermined reference position. Furthermore, the neutral position refers to the reference position where the actual steering angle θs is approximately zero, which is the position of the steering wheel SW when the vehicle is traveling approximately in a straight line at 100°.

[0067] 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. The steering ECU 60 can apply auxiliary torque to the steering device 63 to assist the driver's steering operations through the drive of the steering motor 62.

[0068] Furthermore, during collision avoidance control, when the steering ECU 60 receives a steering command from the driver assistance ECU 10, it drives the steering motor 62 via the motor driver 61 based on the target steering torque determined by the steering command. Thus, the steering ECU 60 generates a steering torque to match the target steering torque. This steering torque differs from the aforementioned auxiliary torque; it is the torque applied to the steering device 63 based on the steering command from the driver assistance ECU 10. Therefore, during collision avoidance control, the driver assistance ECU 10 can automatically change the rudder angle of the vehicle 100's steering wheels via the steering ECU 60 without driver steering input.

[0069] [Collision avoidance control]

[0070] Next, based on Figure 2 and Figure 3 This section provides a general overview of how collision avoidance and mitigation control works. For example... Figure 2As shown, suppose that while vehicle 100 is traveling, for example, in lane LA1, which is a straight road, a situation arises where a three-dimensional object (target object), i.e., obstacle OB, is present and has a high probability of colliding with vehicle 100. In this case, the driver assistance ECU 10 executes collision avoidance control to prevent vehicle 100 from colliding with obstacle OB. Collision avoidance control refers to the control that automatically steers the steering wheels of vehicle 100 to avoid collision with obstacle OB without deviating from lane LA1. Here, automatic steering includes the concept of steering assistance that assists the driver in steering operations to prevent vehicle 100 from colliding with obstacle OB.

[0071] Specifically, as a collision avoidance control, the driver assistance ECU 10, after executing "first steering control" to avoid collision with obstacle OB, executes "second steering control" to keep the vehicle 100 within the driving lane LA1. In the first steering control, a "first steering increase steering" (refer to section S1) is performed, increasing the steering angle from, for example, a neutral position (with the steering angle approximately 0). In the second steering control, a "first steering return steering" (refer to section S2) is performed sequentially, returning the steering angle increased by the first steering control to the neutral position; a "second steering increase steering" (refer to section S3) is performed, increasing the steering angle from the neutral position in the opposite direction to the steering direction of the first steering control; and a "second steering return steering" (refer to section S4) is performed, returning the steering angle back to the neutral position.

[0072] Figure 3 This is a control block diagram of a driver assistance ECU 10 that implements collision avoidance control. The driver assistance ECU 10 includes 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 steering angle calculation unit 12, a FF control quantity calculation unit 13, an FB control quantity calculation unit 14, a subtraction calculation unit 15, an auxiliary torque calculation unit 16, a counteracting torque calculation unit 17, and an addition calculation unit 18 as some of its functional elements. These functional elements are described as components of the driver assistance ECU 10, which is integrated into a single piece of hardware. However, any part of these elements can also be located in another ECU separate from the driver assistance ECU 10. Furthermore, all or part of the functional elements of the driver assistance ECU 10 can also be located in an information processing device of a facility (such as a management center) capable of communicating with the vehicle 100.

[0073] 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 2The 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 side of the vehicle 100 based on target 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 determined three-dimensional objects. Specifically, the object information acquisition unit 11A uses a coordinate system with the center of the front of the vehicle 100 as the origin and extending left, right, and forward from that origin to generate coordinate information of the three-dimensional objects, including their position coordinates.

[0074] For each of all three-dimensional objects acquired by the three-dimensional object information acquisition unit 11A, the obstacle determination unit 11B determines whether the three-dimensional object is an obstacle OB that may collide with its own vehicle 100. Specifically, the obstacle determination unit 11B calculates the trajectory 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.

[0075] 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 are maintaining their current moving states. Additionally, when the three-dimensional object is stationary, the driver assistance ECU 10 performs this determination process based on the trajectory of its own vehicle 100 and the current position of the three-dimensional object. Based on the determination result, if the obstacle determination unit 11B determines that its own vehicle 100 is likely to collide with the three-dimensional object, it classifies that three-dimensional object as an obstacle OB.

[0076] When an obstacle is determined by obstacle determination unit 11B to be an obstacle OB, collision determination unit 11C calculates the predicted time (Time To Collision, hereinafter referred to as "TTC") until the vehicle 100 collides with 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 TTC is below a predetermined collision determination threshold TTCth, collision determination unit 11C determines that the probability of the vehicle 100 colliding with the obstacle OB is high.

[0077] 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 uses a known method to calculate a track in which the vehicle 100 and the obstacle OB do not interfere with each other and can avoid collision, and sets the calculated track as the target track Rt (refer to...). Figure 2 (For example, refer to Japanese Patent Application Publication No. 2017-43262 and Japanese Patent Application Publication No. 2018-106230, etc.). In this case, based on the target information of the obstacle OB and the positions of the white lines WL and WR on the left and right, a target track Rt is generated within a range that allows the vehicle 100 to pass through the collision avoidance space SP1 set on either the left or right side of the obstacle OB without deviating from the driving lane LA1.

[0078] 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.

[0079] When 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 based on the current vehicle speed V of the vehicle 100 and the target yaw rate required for the 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 calculation unit 15.

[0080] 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 Here, the target steering torque T of FF is... FF This refers to the torque control quantity required to propel the vehicle 100 along the target trajectory Rt without generating a driver's steering torque Tdr due to driver steering or control operations. The FF control quantity calculation unit 13 calculates, for example, the target steering torque T based on the target rudder angle θt and referring to a pre-stored FF torque map (not shown). FF The torque mapping for FF is set such 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... FFThe 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 unit 18.

[0081] The subtraction calculation unit 15 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 calculation unit 15 sends the calculated deviation Δθ to the FB control quantity calculation unit 14.

[0082] 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 FB 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 unit 18.

[0083] The auxiliary torque calculation unit 16 calculates the auxiliary torque T, which is used as an auxiliary control quantity to assist the pilot's steering operations. AS The auxiliary torque calculation unit 16 calculates the auxiliary torque T, for example, based on the driver's steering torque Tdr and the vehicle speed V, and referring to a pre-stored auxiliary torque map (not shown). AS The driver's steering torque Tdr can be obtained based on the detection results of the steering torque sensor 65, and the vehicle speed V can be obtained based on the detection results of the vehicle speed sensor 21. The auxiliary torque mapping is preferably set to the auxiliary torque T. AS The absolute value increases as the driver's steering torque Tdr (absolute value) increases, and is set as the auxiliary torque T. AS The absolute value increases as the vehicle speed V decreases. Additionally, the auxiliary torque T... AS The calculation is not limited to using a mapping method; it can also be based on a formula. The auxiliary torque calculation unit 16 calculates the auxiliary torque T. AS The auxiliary torque is sent to the offset torque calculation unit 17 and the steering ECU 60. When the auxiliary torque T is received from the auxiliary torque calculation unit 16... AS At that time, the steering ECU 60 controls the current supplied to the steering motor 62 so that the torque generated by the steering motor 62 is equal to the auxiliary torque T. AS Consistent.

[0084] The torque cancellation calculation unit 17 calculates the torque cancellation torque Tdr and auxiliary torque T during the execution of collision avoidance control. AS The applied counteracting torque T CASpecifically, the torque cancellation calculation unit 17 includes a basic torque cancellation calculation unit 17A, a gain setting unit 17B, and a multiplication calculation unit 17C.

[0085] The basic torque cancellation calculation unit 17A calculates to completely eliminate the driver's steering torque Tdr and auxiliary torque T. AS The total torque T obtained by the driver is calculated in total. SUM (=Tdr+T AS The steering torque, i.e., the basic canceling torque T, is... CA1 (=-T SUM Here, the driver's steering torque Tdr is a concept that includes both the steering torque generated by the driver's steering operation of the steering wheel SW and the steering torque generated by the driver's hands holding the steering wheel SW (holding the steering wheel). The driver's steering torque Tdr can be obtained based on the detection results of the steering torque sensor 65.

[0086] The basic torque compensation unit 17A calculates the pilot's steering torque Tdr and the auxiliary torque T AS The sum of the values ​​is reversed, and the calculation basically cancels out the torque T. CA1 That is, if the driver's total torque T SUM If the value is positive (in the left-turn direction), then the torque T is basically canceled out. CA1 If the total torque T of the driver becomes negative (in the right turn direction), it will become negative. SUM If the value is negative (right turn direction), then the torque T is basically canceled out. CA1 It becomes a positive value (left turn direction). The basic offset torque calculation unit 17A calculates the basic offset torque T. CA1 Send to the multiplication unit 17C.

[0087] Gain setting unit 17B sets and eliminates the driver's total torque T SUM The control gain K is equivalent to the cancellation rate. The gain setting unit 17B sets the control gain K in the range of "0" to "1". Details of the setting of the control gain K will be explained later. The gain setting unit 17B sends the set control gain K to the multiplication operation unit 17C.

[0088] The multiplication unit 17C calculates the basic canceling torque T sent from the basic canceling torque calculation unit 17A. CA1 The value obtained by multiplying the control gain K sent from the gain setting unit 17B (=T) CA1 ×K), and use this value as the final offset torque T. CA Send to addition unit 18.

[0089] The addition calculation unit 18 calculates the target steering torque T of the FF sent from the FF control quantity calculation unit 13. FFAdding the FB target steering torque T sent from the FB control quantity calculation unit 14 FB Calculate the target steering torque Tt (=T FF +T FB Additionally, the addition unit 18 calculates the addition of the offset torque T sent from the multiplication unit 17C to the target steering torque Tt. CA (=T CA1 The value obtained by multiplying K) is the automatic steering torque control quantity Tc (=T FF +T FB +T CA The automatic steering torque control quantity Tc is then sent to the steering ECU 60 as the final control quantity for collision avoidance control. When the automatic steering torque control quantity Tc is received from the addition unit 18, the steering ECU 60 controls the current supplied to the steering motor 62 so that the torque generated by the steering motor 62 is equal to the automatic steering torque control quantity Tc and the auxiliary torque Tc. AS The value obtained by adding them together (=T) FF +T FB +T CA +T AS This ensures consistency. Therefore, it eliminates the driver's total torque T during the execution of collision avoidance control. SUM The automatic steering system guides the vehicle 100 along the target trajectory Rt.

[0090] Next, based on Figure 4 and Figure 5 Applying a counteracting torque T during the execution of collision avoidance control. CA The situation and not applying the counteracting torque T CA The situations are compared. Figure 4 Is applying a counteracting torque T CA One example of this embodiment, Figure 5 No offset torque T is applied CA Comparative examples. Furthermore, in Figure 4 , Figure 5 In the example shown, vehicle 100 avoids a collision with obstacle OB by turning left, while when avoiding it by turning right, only the rudder angle and steering torque are reversed. Therefore, the explanation of right-turn steering is omitted below.

[0091] First, from Figure 5 The comparative example shown will be explained below. When the driver is inattentively holding the steering wheel (SW) while the collision avoidance control is being executed, such as... Figure 5 As shown by the dashed line in (A), the steering wheels of vehicle 100 are subjected to a total driver torque T, which is the sum of the driver steering torque generated by the driver's steering and the auxiliary torque corresponding to the driver steering torque. SUMThe driver's total torque T SUM It acts in the opposite direction to the control torque generated by the automatic steering system, which is controlled by collision avoidance. That is, the total torque T of the driver... SUM In the first steering control (interval S1) and the first steering return control (interval S2) of the second steering control, it becomes the target steering torque T of FF. FF The negative value in the opposite direction becomes the target steering torque T of FF during the second steering control's second steering increase (interval S3) and second steering return (interval S4). FF A positive value in the opposite direction.

[0092] If this total driver torque T is applied during the execution of collision avoidance control... SUM ,but Figure 5 In (A), the total torque T of the driver is shown by the dashed line. SUM and FF target steering torque T FF The combined torque T obtained by synthesis TAL The (absolute value) becomes less than the target steering torque T of FF. FF (Absolute value). That is, such as... Figure 5 As shown by the dashed line in (B), this will cause a deterioration in the rudder angle following performance, where the actual rudder angle θs deviates from the target rudder angle θt. As a result, in the first steering control, there is a possibility that a collision between the vehicle 100 and the obstacle OB cannot be avoided, and in the second steering control, there is a possibility that the vehicle 100 cannot be reliably kept within the driving lane LA1.

[0093] Figure 4 Is applying a counteracting torque T CA This is the implementation method. Furthermore, in... Figure 4 In the example shown, it is assumed that the control gain K is set to "1", that is, the cancellation rate is set to 100%. Figure 4 In the embodiment shown, the driver assistance ECU 10 applies a total torque T to the driver during the execution of collision avoidance control. SUM The basic canceling torque T is completely eliminated CA1 (Refer to the double-dotted line in the diagram). That is, in the first steering control (interval S1) and the first rudder return steering (interval S2) of the second steering control, the steering torque T for the FF target is... FF Adding the total torque T with the driver SUM The fundamental canceling torque T in the opposite positive value CA1 In the second steering control, during the second steering increase (interval S3) and the second steering return (interval S4), the steering torque T for the FF target is... FF Adding the total torque T with the driver SUM The fundamental canceling torque T with a negative value in the opposite direction CA1 .

[0094] When this basic offsetting torque T CA1 The steering torque T added to the FF target FF hour, Figure 4 In (A), the total torque T of the driver is shown by the dashed line. SUM FF target steering torque T FF and basic offset torque T CA1 The combined torque T obtained by synthesis TAL (Absolute value) and FF target steering torque T FF The absolute values ​​are roughly the same. That is, as... Figure 4 As shown by the dashed line in (B), this will improve the rudder angle following performance, ensuring that the actual rudder angle θs is approximately consistent with the target rudder angle θt. As a result, in the first steering control, collisions between the vehicle 100 and the obstacle OB can be reliably avoided, and in the second steering control, the vehicle 100 can be reliably kept within the driving lane LA1.

[0095] Here, if the control gain K is always set to "1", that is, the cancellation rate is always set to 100%, then when the driver intends to operate the steering wheel SW, it will seriously hinder the driver's steering operation and may cause dangerous behavior of the vehicle 100. Therefore, the gain setting unit 17B of this embodiment (shown in Figure 3 If the driver's steering intervention is detected, the control gain K is set appropriately to a smaller value.

[0096] Specifically, the memory of the driver assistance ECU10 pre-stores... Figure 6 The gain setting map M is shown. In the gain setting map M, for example, the control gain K is defined on the vertical axis and the driver's steering torque Tdr is defined on the horizontal axis. The gain setting unit 17B sets the control gain K corresponding to the driver's steering torque Tdr by referring to the gain setting map M based on the driver's steering torque Tdr detected by the steering torque sensor 65.

[0097] In the gain setting mapping M of this embodiment, a first threshold torque Tth1 and a second threshold torque Tth2 are set to determine whether the driver intends to steer. The first threshold torque Tth1 and the second threshold torque Tth2 can be set in advance through experiments, simulations, etc.

[0098] The first threshold torque Tth1 is preset based on the maximum value of the steering torque when the driver casually holds the steering wheel SW (holding the rudder). When the driver's steering torque Tdr is less than or equal to the first threshold torque Tth1 (Tdr ≤ Tth1), the control gain K is set to "1" (cancellation rate: 100%). That is, when the driver casually holds the rudder during the execution of the collision avoidance control, a cancellation torque T will be applied to completely cancel the combined driver torque T AS obtained by adding the driver's steering torque Tdr and the assist torque T SUM of the cancellation torque T CA (= basic cancellation torque T CA1 × 1). Thereby, the rudder angle followability of the automatic steering can be reliably improved.

[0099] The second threshold torque Tth2 is preset based on the minimum value of the steering torque when the driver intentionally operates the steering wheel SW. The second threshold torque Tth2 is a value greater than the first threshold torque Tth1 (Tth2 > Tth1). When the driver's steering torque Tdr is greater than or equal to the second threshold torque Tth2 (Tdr ≥ Tth2), the control gain K is set to "0" (cancellation rate: 0%). That is, when the driver intentionally performs a steering operation during the execution of the collision avoidance control, the cancellation torque T SUM of the combined driver torque T CA is set to "0". Thereby, it is possible to effectively prevent the driver's steering operation from being hindered when the driver has the intention to steer.

[0100] When the driver's steering torque Tdr is between the first threshold torque Tth1 and the second threshold torque Tth2 (Tth1 < Tdr < Tth2), there is a possibility that the driver is intentionally performing a steering operation, and there is also a possibility that the driver casually holds the steering wheel SW (holding the rudder). In this case, the control gain K is set to become "0" as the driver's steering torque Tdr increases from the first threshold torque Tth1 to the second threshold torque Tth2. That is, the greater the driver's steering torque Tdr, the smaller the control gain K is set. Thus, when there is a possibility that the driver has the intention to steer and there is also a possibility of casually holding the rudder, by gradually reducing the control gain K from "1" to "0" as the driver's steering torque Tdr increases, it is possible to suppress the decrease in the rudder angle followability of the automatic steering and effectively prevent the driver's steering operation from being seriously hindered.

[0101] Next, based on Figure 7 the flowchart shown, an example routine of the collision avoidance control process performed by the driving assistance ECU10 will be described. During the driving of the vehicle 100, the driving assistance ECU10 repeatedly executes at a predetermined cycle Figure 7 The processing after step S100.

[0102] In step S100, the driving assistance 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.

[0103] Next, in step S105, the driver assistance ECU 10 determines whether there are any three-dimensional objects in the areas in front of and to the side of its own vehicle 100 based on the target object information sent from the surrounding recognition device 30. If there are three-dimensional objects (yes), the driver assistance ECU 10 proceeds to step S110. On the other hand, if there are no three-dimensional objects (no), the driver assistance ECU 10 temporarily terminates the current routine (returns).

[0104] In step S110, the driver assistance ECU 10 acquires the position information of the three-dimensional object. Next, in step S115, the driver assistance ECU 10 determines whether the three-dimensional object is an obstacle OB that may collide with its own vehicle 100. If the driver assistance ECU 10 determines that the three-dimensional object may collide with its own vehicle 100, it determines that the three-dimensional object is an obstacle OB. If the three-dimensional object is determined to be an obstacle OB (yes), the driver assistance 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 driver assistance ECU 10 temporarily terminates the current routine (returns).

[0105] In step S120, the driver assistance ECU 10 calculates the TTC (Traffic Troubleshooting). Next, in step S125, the driver assistance 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 driver assistance ECU 10 proceeds to step S130. On the other hand, if the TTC is not below the collision determination threshold TTCth (No), the driver assistance ECU 10 temporarily terminates the current routine (returns).

[0106] In step S130, the driver assistance ECU 10 determines that the probability of its own vehicle 100 colliding with the obstacle OB is high. Next, in step S140, the driver assistance ECU 10 sets a target trajectory Rt that allows its own vehicle 100 to avoid collision with the obstacle OB without deviating from the driving lane LA1, and proceeds to step S150. Furthermore, although detailed explanations are omitted, without the aforementioned collision avoidance space SP1 (refer to...) Figure 2 If the target trajectory Rt cannot be set, the driver assistance ECU10 can simply perform collision avoidance control through braking control.

[0107] In step S150, the driver assistance ECU 10 begins automatic steering based on collision avoidance control. Specifically, the driver assistance ECU 10 begins first steering control: performing a first steering increase steering that increases the rudder angle of the vehicle 100 to allow the vehicle 100 to travel along the target trajectory Rt while avoiding the obstacle OB. In step S155, when the termination condition of the first steering control is met, the driver assistance ECU 10 proceeds to step S160. The first steering control is, for example, based on the target steering torque T available from FF. FF The obtained rudder angle profile can be used as the control endpoint when the rudder angle begins to gradually decrease from its maximum value.

[0108] In step S160, the driver assistance ECU 10 begins second steering control: increasing or decreasing the rudder angle of its own vehicle 100 to keep the vehicle 100 traveling along the target trajectory Rt and remaining within the driving lane LA1. 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 back to the neutral position. In step S165, when the termination condition of the second steering control is met, the driver assistance ECU 10 temporarily terminates the current routine (returns). The second steering control can terminate, for example, when the yaw angle of the vehicle 100 is approximately parallel to the driving lane LA1 (white lines WL, WR), or when the actual rudder angle θs falls within the desired angle range.

[0109] Next, based on Figure 8 The flowchart shown illustrates the routine of torque cancellation control performed by the driver assistance ECU 10. During the driving of the vehicle 100, the driver assistance ECU 10 repeatedly interacts with... Figure 7 The routines shown are executed in parallel. Figure 8 The torque cancellation control is shown.

[0110] In step S200, the driving assistance ECU 10 determines whether the first steering control has been initiated. If the first steering control has been initiated (yes), the driving assistance ECU 10 proceeds to step S210. On the other hand, if the first steering control has not been initiated (no), the driving assistance ECU 10 temporarily terminates the current routine (returns).

[0111] In step S210, the driving assistance ECU 10 determines whether the driver's steering torque Tdr detected by the steering torque sensor 65 is below the first threshold torque Tth1. When the driver's steering torque Tdr is below the first threshold torque Tth1 (Yes), the driving assistance ECU 10 proceeds to the process of step S220, sets the control gain K to "1", and applies a cancellation torque T SUM (= Tdr + T AS ) that completely cancels the driver's total torque T CA (= basic cancellation torque T CA1 × 1). Thereby, the rudder angle followability of the automatic steering can be improved. On the other hand, in the determination of step S210, when the driver's steering torque Tdr is not below the first threshold torque Tth1 (No), the driving assistance ECU 10 proceeds to the process of step S230.

[0112] In step S230, the driving assistance ECU 10 determines whether the driver's steering torque Tdr detected by the steering torque sensor 65 is above the second threshold torque Tth2. When the driver's steering torque Tdr is above the second threshold torque Tth2 (Yes), the driving assistance ECU 10 proceeds to the process of step S240 and sets the control gain K to "0". That is, no cancellation torque T CA is applied. Thereby, when the driver has the intention to steer, it is possible to effectively prevent the driver's steering operation from being obstructed. On the other hand, in the determination of step S230, when the driver's steering torque Tdr is not above the second threshold torque Tth2 (No), the driving assistance ECU 10 proceeds to the process of step S250.

[0113] In step S250, the driving assistance ECU 10 sets the control gain K within a range greater than "0" and less than "1" (0 < K < 1) in such a way that the greater the driver's steering torque Tdr, the smaller the setting. That is, as the driver's steering torque Tdr increases, the control gain K is gradually decreased. Thereby, it is possible to suppress the decrease in the rudder angle followability of the automatic steering and effectively prevent the driver's steering operation from being severely obstructed.

[0114] When entering step S260 from steps S220, S240, and S250, the driving assistance ECU 10 determines whether the second steering control has ended. When the second steering control has ended (Yes), the driving assistance ECU 10 temporarily ends this routine (returns). On the other hand, when the second steering control has not ended (No), the driving assistance ECU 10 returns to the determination of step S210. That is, during the period until the automatic steering based on the collision avoidance control ends, the driving assistance ECU 10 repeatedly executes the respective processes of steps S210 to S260 described above.

[0115] As described above, when the driving assistance ECU 10 of this embodiment detects an obstacle OB with a high probability of collision with its own vehicle 100 in the area in front of and to the side of the vehicle 100, it sets a target trajectory Rt that allows the vehicle 100 to avoid collision with the obstacle OB without deviating from the driving lane LA1, and implements automatic steering by controlling the steering angle of the vehicle 100 so that the vehicle 100 travels along the target trajectory Rt. As automatic steering, the driving assistance ECU 10 sequentially executes a first steering control to avoid collision between the vehicle 100 and the obstacle OB, and a second steering control to prevent the vehicle 100 from deviating from the driving lane LA1. In addition, during the execution of automatic steering, the driving assistance ECU 10 applies a force to eliminate the driver steering torque Tdr generated by the driver's steering or rudder control and the auxiliary torque T generated based on the driver steering torque Tdr. AS The total torque T of the driver obtained by calculation SUM (=Tdr+T AS The offset torque T) CA Therefore, in the execution of automatic steering based on collision avoidance control, the rudder angle following performance can be improved, ensuring that the actual rudder angle θs is approximately consistent with the target rudder angle θt. Through this improved rudder angle following performance, in the first steering control, collisions between the vehicle 100 and the obstacle OB can be reliably avoided; and in the second steering control, the vehicle 100 can be reliably kept within the driving lane LA1.

[0116] [other]

[0117] The driving assistance device, driving assistance method and procedure involved in this embodiment have been described above, but this disclosure is not limited to the above embodiment. Various modifications can be made as long as they do not depart from the purpose of this disclosure.

[0118] [Variation Example 1]

[0119] In variation example 1, such as Figure 9 As shown, during automatic steering, if the driver's steering torque Tdr detected by the steering torque sensor 65 remains above a predetermined threshold torque Tth for a predetermined threshold time Sth (or threshold distance) or more (refer to times t1 to t2), the driver's steering intention is determined, and the control gain K is gradually reduced from "1" to "0". On the other hand, if the driver's steering torque Tdr does not remain above the threshold torque Tth for a predetermined threshold time Sth, or if the driver's steering torque Tdr is less than the threshold torque Tth, the control gain K is maintained at "1".

[0120] When gradually decreasing the control gain K from "1" to "0", it is preferable to set a gradual decrease time (referencing times t2 to t3) that limits the amount of decrease in control gain K per unit time to prevent sudden changes in the pilot's steering torque Tdr. The larger the pilot's steering torque Tdr, the longer the gradual decrease time should be set. The combination of threshold torque Tth and threshold time Sth is not limited to one mode; multiple modes can be set, such as shortening the threshold time Sth when the threshold torque Tth is large, and extending the threshold time Sth when the threshold torque Tth is small.

[0121] Thus, if the pilot's steering torque Tdr remains above the threshold torque Tth for a duration of Sth or more, gradually reducing the control gain K from "1" to "0" effectively prevents the pilot's steering operation from being hindered when the pilot intends to take control. Furthermore, if the pilot's steering torque Tdr does not remain above the threshold torque Tth for a duration of Sth or more, or if the pilot's steering torque Tdr is less than the threshold torque Tth, maintaining the control gain K at "1" effectively prevents a decrease in autopilot angle following performance when the pilot is not actively maintaining control.

[0122] [Variation Example 2]

[0123] In variation example 2, such as Figure 10 As shown, the driving assistance ECU10 is based on the target steering torque T of the automatic steering FF. FF The deviation ΔT (=T) from the driver's steering torque Tdr detected by steering torque sensor 65 FF The absolute value of the deviation ΔT is used to determine the control gain K. The larger the absolute value of ΔT, the smaller the control gain K is set. Specifically, when the deviation ΔT is below a predetermined threshold, the control gain K gradually decreases as ΔT increases. When the deviation ΔT exceeds the threshold, the control gain K is set to "0".

[0124] Thus, by adjusting the target steering torque T of FF FF As the deviation ΔT from the pilot's steering torque Tdr increases, the control gain K gradually decreases, thus enabling the application of the optimal counteracting torque T corresponding to the strength (degree) of the pilot's steering intention. CA Therefore, it can effectively prevent severe obstruction of the pilot's steering operation when the pilot's steering intention is strong, and effectively prevent a significant reduction in the autopilot's rudder angle following performance when the pilot's steering intention is weak. Furthermore, the deviation ΔT can also be the target steering torque Tt (=T FF +T FB The difference between the pilot's steering torque Tdr and the torque Tdr.

[0125] [Variation Example 3]

[0126] In the above-described variation 2, the driving assistance ECU 10 can also adjust the steering torque T even if the target FF is reached. FF The deviation ΔT from the driver's steering torque Tdr is below the threshold, but the target steering torque T of the FF is... FF If the deviation from the driver's steering torque Tdr persists for more than a predetermined threshold time, it is determined that the driver intends to take control, and the control gain K is gradually reduced to "0". In this case, when gradually reducing the control gain K to "0", similar to the above-described variation 1, it is preferable to set a gradual reduction time that limits the amount of reduction of the control gain K per unit time to prevent sudden changes in the driver's steering torque Tdr.

[0127] Thus, at the target steering torque T of FF FF If the deviation from the pilot's steering torque Tdr persists for more than a threshold time, gradually reducing the control gain K to "0" can effectively prevent the pilot's steering operation from being hindered once the pilot's steering intention is clear. Furthermore, regarding the target steering torque Tdr at FF... FF Until the state deviates from the driver's steering torque Tdr for more than a threshold time, a counteracting torque T based on the control gain K is applied. CA It can effectively prevent the reduction of autopilot angle following during the period until the driver's steering intention is clear.

[0128] [Variation Example 4]

[0129] The driver's inattentive grip on the steering wheel (SW) can also be determined based on the periodic changes (fluctuations) in the driver's steering torque (Tdr). For example... Figure 11 As shown, when the driver's steering torque Tdr detected by the steering torque sensor 65 repeatedly increases or decreases within a predetermined torque range T1 to T2, it is inferred that the driver's steering direction is undetermined. In this case, the driver assistance ECU 10 determines that the driver is carelessly holding the steering wheel SW (steering hold) and maintains the control gain K setting at "1".

[0130] Thus, based on the periodic increase and decrease of the driver's steering torque Tdr, the driving state of the driver carelessly holding the steering wheel SW (steering hold) can be determined. During the period when the driver is determined to be carelessly holding the steering wheel, by keeping the control gain K set to "1", the steering angle following performance of the automatic steering can be effectively improved.

[0131] [Variation Example 5]

[0132] In the above-described embodiments and variations 1 to 4, the presence or absence of the driver's steering intention is determined based on the driver's steering torque Tdr detected by the steering torque sensor 65. However, immediately after the automatic steering (first steering control) based on collision avoidance control begins, the steering torque sensor 65 will detect the steering torque Tdr generated by the steering inertia and the driver's steering effort, which is related to the FF target steering torque. FF A large reverse torque in the opposite direction. If the driver's intention to steer is determined based on the detection results that include this reverse torque, it may lead to misjudgment.

[0133] In Variation 5, the driving assistance ECU 10 does not make a determination based on the detection result of the steering torque sensor 65 until a predetermined time has elapsed since the start of the first steering control. Specifically, in the above embodiment, the driving assistance ECU 10... Figure 8 Between steps S200 and S210 of the illustrated process, step S205 is performed to determine whether the elapsed time since the start of the first steering control has reached a predetermined time. In this case, if the elapsed time has reached the predetermined time, the process proceeds to step S210. Furthermore, in the above-described variation 1, the driver assistance ECU 10 begins determining whether the driver's steering torque Tdr is above a predetermined threshold torque Tth when a predetermined time has elapsed since the start of the first steering control. Furthermore, in the above-described variations 2 and 3, the driver assistance ECU 10 calculates the target steering torque TFF when a predetermined time has elapsed since the start of the first steering control. FF The deviation ΔT from the driver's steering torque Tdr. Furthermore, in the above-described variation 4, the driver assistance ECU 10 begins determining whether the driver's steering torque Tdr changes within a predetermined torque range T1 to T2 after a predetermined time has elapsed since the start of the first steering control. Thus, by starting the determination after a predetermined time has elapsed since the start of the first steering control, it is possible to effectively prevent misjudgments based on reverse torque.

Claims

1. A driving assistance device that, upon detecting an obstacle with a high probability of collision with its own vehicle in the area in front of and to the side of its own vehicle, implements collision avoidance control to control the steering angle of its own vehicle so that the own vehicle travels along a target trajectory that avoids collision with the obstacle without deviating from its driving lane, the driving assistance device comprising: The target steering torque setting unit sets the target rudder angle required for the vehicle to travel along the target trajectory, and sets the target steering torque that makes the vehicle's rudder angle consistent with the target rudder angle when no driver steering torque is generated as the driver of the vehicle performs steering wheel holding or steering operations. A torque-reducing unit sets a torque that eliminates the torque in the direction of the total steering torque obtained by summing the pilot's steering torque and a steering assist torque set based on the pilot's steering torque; and The steering control unit performs steering control based on a torque control quantity obtained by adding the target steering torque to the counteracting torque, thereby controlling the rudder angle of the vehicle itself. The torque offset setting unit includes: The basic offset torque setting unit sets a basic offset torque for completely eliminating the total steering torque; and The gain setting unit is configured to compensate for the gain loss corresponding to the magnitude of the driver's steering torque. The offset torque is set by multiplying the basic offset torque by the offset gain.

2. The driving assistance device according to claim 1, The gain setting unit sets the offset gain to a smaller value as the driver's steering torque increases.

3. The driving assistance device according to claim 1, If the gain setting unit continues for a predetermined threshold time or longer when the driver's steering torque is above a predetermined threshold torque, the cancellation gain is set to 0.

4. The driving assistance device according to claim 1, The gain setting unit sets the cancellation gain to a smaller value as the deviation between the target steering torque and the driver's steering torque increases, and sets the cancellation gain to 0 when the deviation exceeds a predetermined threshold.

5. The driving assistance device according to claim 4, If the deviation amount remains below the threshold for a predetermined threshold time or longer, the gain setting unit also sets the cancellation gain to 0.

6. The driving assistance device according to claim 1, The gain setting unit sets the cancellation gain to 1 when the driver's steering torque increases or decreases within a predetermined torque range.

7. A driving assistance method, which, when an obstacle with a high probability of collision with the vehicle is detected in the area in front of and to the side of the vehicle, implements a collision avoidance control method to control the steering angle of the vehicle so that the vehicle travels along a target trajectory that avoids collision with the obstacle without deviating from the driving lane, comprising: Set a target rudder angle required for the vehicle to travel along the target trajectory, and set a target steering torque that makes the vehicle's rudder angle match the target rudder angle without generating driver steering torque due to the driver's steering wheel operation. A cancelling torque is set, which is a torque that eliminates the direction of the total steering torque obtained by summing the pilot's steering torque and the steering assist torque set based on the pilot's steering torque; and The steering control is performed based on a torque control quantity obtained by adding the target steering torque to the counteracting torque, thereby controlling the rudder angle of the vehicle itself. Setting the offsetting torque includes: Set a basic offset torque for completely eliminating the total steering torque; and Set a cancellation gain corresponding to the magnitude of the driver's steering torque. The offset torque is set by multiplying the basic offset torque by the offset gain.

8. A computer program product comprising a program that causes a computer of a driving assistance device to perform the following processing: when the driving assistance device detects an obstacle with a high probability of collision with its own vehicle in areas in front of and to the side of its own vehicle, the driving assistance device implements collision avoidance control by controlling the steering angle of its own vehicle to cause the own vehicle to travel along a target trajectory that avoids collision with the obstacle without deviating from its driving lane, the processing comprising: Set a target rudder angle required for the vehicle to travel along the target trajectory, and set a target steering torque that makes the vehicle's rudder angle match the target rudder angle without generating driver steering torque due to the driver's steering wheel operation. A cancelling torque is set, which is a torque that eliminates the direction of the total steering torque obtained by summing the pilot's steering torque and the steering assist torque set based on the pilot's steering torque; and The steering control is performed based on a torque control quantity obtained by adding the target steering torque to the counteracting torque, thereby controlling the rudder angle of the vehicle itself. Setting the offsetting torque includes: Set a basic offset torque for completely eliminating the total steering torque; and Set a cancellation gain corresponding to the magnitude of the driver's steering torque. The offset torque is set by multiplying the basic offset torque by the offset gain.

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