Vehicle control device, vehicle control method, and vehicle control program

Abstract

PURPOSE: To provide a vehicle control device that can realize steering operation feeling suitable for a travel scene.SOLUTION: A processor of a vehicle control device 1 controls an electric motor 32 such that when a driver rotates a steering wheel SW in a predetermined first travel scene in which lane trace control is in execution, operation torque Ts of the steering wheel SW matches a predetermined first target value, and controls the electric motor 32 such that when the driver rotates the steering wheel SW in a predetermined second travel scene in which the lane trace control is in execution, the second travel scene being defined in advance as a travel scene in which the operation frequency of the rotated steering wheel SW is lower than in the first travel scene, operation torque Ts of the steering wheel SW matches a second target value smaller than the first target value.SELECTED DRAWING: Figure 4

Description

Technical Field

[0001] The present invention relates to a vehicle control device, a vehicle control method, and a vehicle control program that control a steering device so that a host vehicle travels along a driving lane.

Background Art

[0002] A vehicle control device capable of executing lane trace control for controlling a steering device so that a host vehicle travels along a driving lane has been proposed (see, for example, Patent Document 1 below). A processor of the vehicle control device of Patent Document 1 (hereinafter referred to as "conventional device a1") calculates a target value θd of a steering angle θs for causing the host vehicle to travel along a target travel line Ld based on information acquired from various sensors. Then, the processor controls an electric motor of the steering device so that the steering angle θs (measured value) of the host vehicle matches the target value θd.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

[0004] When lane trace control is being executed and the host vehicle is traveling along the target travel line Ld (θs = θd), a driver may rotate the steering wheel, for example, for lane change or obstacle avoidance (steering override (SOR)). That is, the steering angle θs deviates from the target value θd. In this case, the conventional device a1 interrupts the lane trace control, but a vehicle control device (hereinafter referred to as "conventional device a2") configured to continue the lane trace control has also been proposed. When the steering wheel is rotated during execution of the lane trace control, a processor of the conventional device a2 controls the electric motor so that the steering torque Ts is reduced.

[0005] Incidentally, in driving scenarios where the driver frequently rotates the steering wheel while lane tracing control is being performed, it is preferable for the steering torque Ts (reaction force) to be small (light feel) in order to reduce driver fatigue. On the other hand, in driving scenarios where the driver frequently rotates the steering wheel while lane tracing control is being performed, it is preferable for the steering torque Ts (reaction force) to be large (heavy feel) in order to prevent the driver from unintentionally rotating the steering wheel. According to the conventional device a2 described above, when the driver rotates the steering wheel while lane tracing control is being performed, the steering torque Ts is reduced, but the amount of reduction is independent of the type of driving scenario. Therefore, there is a risk that a steering feel suitable for the driving scenario may not be obtained.

[0006] One of the objectives of the present invention is to provide a vehicle control device that can achieve a steering feel suitable for various driving situations.

[0007] To achieve the above objective, the vehicle control device (1) of the present invention is: A steering device (30) comprising sensors (20, 33) that acquire information about the vehicle (V) and information about targets present around the vehicle, a steering mechanism (31) that connects the vehicle's steering wheel (SW) to the steering wheel, and an electric motor (32) that drives the steering mechanism, and a steering device (30) that moves along the driving lane in which the vehicle is traveling, The system determines the target steering angle of the vehicle, calculates the lane-tracing torque which is the torque applied to the steering mechanism to match the actual steering angle of the vehicle to the target steering angle, and outputs the lane-tracing torque. A processor that performs lane tracing control for controlling the electric motor, wherein when the steering wheel is rotated while the lane tracing control is being performed, In addition to the aforementioned lane tracing torque, The steering wheel So that an assist torque corresponding to the direction of rotation and steering torque is applied to the steering mechanism, The system includes a processor (10) configured to perform steering override control to control the electric motor. The processor is configured to perform steering override control when the driver rotates the steering wheel in a predetermined first driving scene (SH) while the lane tracing control is being performed. The aforementioned assist torqueThe electric motor is controlled so that it matches a predetermined first target value, and in a predetermined second driving scene (SM) in which the lane tracing control is being performed, the second driving scene is defined in advance as a driving scene in which the frequency of the steering wheel being rotated is lower than in the first driving scene, when the driver rotates the steering wheel The aforementioned assist torque However, the electric motor is controlled to match a second target value that is smaller than the first target value. In a predetermined third driving scene (SL) in which the lane tracing control is being performed, the electric motor is controlled so that the assist torque when the driver rotates the steering wheel matches a third target value that is smaller than the second target value, the first driving scene includes at least one of the following: the turn signal is activated, driving on an ordinary road, driving in a construction zone, driving near a large vehicle, detecting an obstacle, or performing a preceding vehicle following control that follows a preceding vehicle, the second driving scene is a situation in which the driver is driving in hands-on mode in which the lane tracing control can be performed only when the driver is holding the steering wheel, and the third driving scene is a situation in hands-off mode in which the driver is driving in which the lane tracing control can be performed even when the driver is not holding the steering wheel, and the first driving scene, the second driving scene and the The system includes a first to third table, each corresponding to one of three driving scenarios. Each of the first to third tables shows the relationship between the steering torque and the target value of the assist torque, and includes a dataset corresponding to multiple vehicle speeds. In each table, for the same steering torque, the absolute value of the assist torque at high speeds is set to be smaller than the absolute value of the assist torque at low speeds. Furthermore, for the same vehicle speed and the same steering torque, the first to third tables are set so that the absolute value of the assist torque defined by the first table is greater than the absolute value of the assist torque defined by the second table, and the absolute value of the assist torque defined by the second table is greater than the absolute value of the assist torque defined by the third table. The processor selects one of the first to third tables according to the recognized driving scenario and determines the target value of the assist torque by referring to the dataset corresponding to the vehicle speed in the selected table.

[0008] The processor of the vehicle control device according to the present invention controls the electric motor so as to reduce the steering wheel operating torque when the driver steers while lane tracing control is being performed. In this case, the processor determines the amount of reduction in operating torque according to the type of driving scene (first driving scene or second driving scene). Therefore, according to the present invention, it is possible to achieve a steering feel suitable for the driving scene.

[0010] According to this, in situations where the driver frequently steers while lane tracing control is in operation, the steering wheel's feel can be set to be relatively light.

[0012] Generally, the frequency with which the driver steers in hands-off mode is lower than the frequency with which the driver steers in hands-on mode. According to this embodiment, the steering wheel's feel can be set to be relatively heavy in hands-off mode, where the driver steers less frequently. [Brief explanation of the drawing]

[0013] [Figure 1] Figure 1 is a block diagram of a vehicle control device according to one embodiment of the present invention. [Figure 2] Figure 2 is a table showing the relationship between steering torque and assist torque. [Figure 3] Figure 3 is a plan view showing the steering wheel being rotated while lane tracing control is being performed. [Figure 4] Figure 4 is a graph showing the changes in steering angle and various torques. [Figure 5] Figure 5 shows a classification table and chart of driving scenes. [Figure 6] Figure 6 is a flowchart of the program that implements the function of reducing steering torque in steering override. [Modes for carrying out the invention]

[0014] (Outline) A vehicle control device 1 according to one embodiment of the present invention is installed in a vehicle V (hereinafter referred to as "the vehicle") equipped with an automatic driving function that automatically drives toward a set destination and a follow function that drives in accordance with a preceding vehicle. The vehicle control device 1 has a function to perform lane tracing control (lane tracing function) that controls the vehicle (steering device 30 described later) so that the vehicle moves along the driving lane. In addition, the vehicle control device 1 has a function to perform steering override control (steering override function) that controls the steering device 30 in accordance with the operation of the steering wheel SW when the driver rotates the steering wheel SW while lane tracing control is being performed.

[0015] (Specific Configuration) As shown in Figure 1, the vehicle control device 1 includes a steering assist ECU 10, an on-board sensor 20, and a steering device 30.

[0016] The steering assist ECU 10 includes a CPU 10a, ROM 10b, RAM 10c, timer 10d, etc. The steering assist ECU 10 is connected to other ECUs via CAN. The steering assist ECU 10 also includes a drive circuit 10e that drives the electric motor 32, which will be described later.

[0017] The on-board sensor 20 includes a millimeter-wave radar 21, sonar 22, and camera 23 as forward sensors that acquire information about targets located in front of the vehicle.

[0018] The millimeter-wave radar 21 includes a transmission / reception unit and a signal processing unit. The transmission / reception unit radiates radio waves in the millimeter-wave band (hereinafter referred to as "millimeter waves") forward of the host vehicle, and receives the millimeter waves (reflected waves) reflected by a three-dimensional object located within the radiation range. The signal processing unit recognizes the distance between the host vehicle and the three-dimensional object (e.g., guardrail, pole, preceding vehicle, etc.), the relative position (direction) of the three-dimensional object with respect to the host vehicle, etc., based on the time from when the transmission / reception unit radiates the millimeter waves until the reflected waves are received, and physical quantities related to the transmitted millimeter waves and the received reflected waves, and transmits the recognition result to the steering assistance ECU 10.

[0019] The sonar 22 intermittently radiates ultrasonic waves (transmission waves) to the peripheral area of the host vehicle, and receives the ultrasonic waves (reflected waves) reflected by a three-dimensional object. The sonar 22 recognizes the distance between the host vehicle and the three-dimensional object, the relative position (direction) of the three-dimensional object with respect to the host vehicle, etc., based on physical quantities related to the transmission waves and the reflected waves, and transmits the recognition result to the steering assistance ECU 10.

[0020] The camera 23 includes an imaging device and an image analysis device. The imaging device incorporates, for example, a CCD. The imaging device is installed at the front part of the host vehicle. The imaging device captures the foreground of the host vehicle at a predetermined frame rate and acquires image data respectively. Each imaging device transmits the image data to the image analysis device. The image analysis device analyzes the acquired image data and recognizes object targets existing around the host vehicle from the image. For example, the image analysis device recognizes other vehicles, lane dividing lines that demarcate the driving lane, curbstones, median strips, etc., and transmits the recognition result to the steering assistance ECU 10.

[0021] Furthermore, the in-vehicle sensor 20 includes a speed sensor 24. The speed sensor 24 detects the speed (actual vehicle speed) of the host vehicle and transmits the detection result to the steering assistance ECU 10.

[0022] Furthermore, the in-vehicle sensor 20 includes a switch 25. The switch 25 includes an operating device for the driver to request the vehicle control device 1 to execute various processes. Specifically, the switch 25 includes a push-button type switch device for requesting to execute lane trace control described later.

[0023] In addition, the vehicle-mounted sensor 20 includes sensors for detecting the operating state of the direction indicator, a navigation system that stores information about the road, a communication device for acquiring information about the construction section (not shown), etc.

[0024] The steering device 30 includes a steering mechanism 31, an electric motor 32, and a steering sensor 33.

[0025] The steering mechanism 31 is a link mechanism that connects the steering wheel SW and the steering wheels (left front wheel and right front wheel). The steering mechanism 31 includes a torsion bar 311, a steering shaft 312, a pinion gear 313, a rack 314, tie rods 315, etc.

[0026] As the electric motor 32, for example, a brushless DC motor can be adopted. The output shaft of the electric motor 32 is connected to a steering mechanism (for example, the steering shaft 312) via a speed reduction mechanism 32a composed of a plurality of gears. That is, the torque of the output shaft of the electric motor 32 is applied to the steering shaft 312 via the speed reduction mechanism 32a. The electric motor 32 operates (rotates forward or reversely) according to a command (drive signal) obtained from the drive circuit 10e.

[0027] The steering sensor 33 includes a steering angle sensor 331 that detects the steering angle θs, and a steering torque sensor 332 that detects the steering torque Ts based on the torsional angle of the torsion bar 311. In addition, the steering sensor 33 includes a touch sensor 333. The touch sensor 333 is incorporated in the steering wheel SW and detects whether the driver is gripping the steering wheel SW. Further, the steering sensor .

[0028] (Operation) When switch 25 is in the off position, the steering assist ECU 10 performs the following power steering control. When switch 25 is in the on position, the steering assist ECU 10 performs the following lane tracing control. In the following description, the clockwise rotation direction of the steering wheel SW and steering shaft 312 as seen from the driver is considered the "positive" rotation direction, and the counterclockwise rotation direction is considered the "negative" rotation direction. Also, various torques in the clockwise direction as seen from the driver are considered "positive," and various torques in the counterclockwise direction are considered "negative."

[0029] <Power Steering Control> The steering support ECU 10 sequentially acquires speed vs from the speed sensor 24, and sequentially acquires steering angle θs and steering torque Ts from the steering sensor 33. Based on speed vs and steering torque Ts, the steering support ECU 10 determines the torque (assist torque Ta) to be applied from the electric motor 32 to the steering shaft 312. Here, the steering support ECU 10 stores a table TBeps (Figure 2) that defines the relationship between speed vs, steering torque Ts and assist torque Ta. The steering support ECU 10 refers to table TBeps to determine the assist torque Ta (torque value). Then, the steering support ECU 10 controls the electric motor 32 (drive circuit 10e) so that the assist torque Ta is applied to the steering shaft 312. As a result, the steering torque Ts and assist torque Ta are applied to the steering shaft 312.

[0030] <Lane Tracing Control> The steering support ECU 10 recognizes the driving lane L in which the vehicle is traveling based on information acquired from forward sensors (at least one of the millimeter-wave radar 21, sonar 22, and camera 23). Next, based on this information, the steering support ECU 10 calculates a target driving line Ld that passes through the center of the driving lane L in the width direction. The steering support ECU 10 acquires the vehicle's speed vs from the speed sensor 24 and the current steering angle θs from the steering sensor 33. Based on the target driving line Ld, speed vs, and current steering angle θs, the steering support ECU 10 calculates a target value θd for the steering angle θs. Then, the steering support ECU 10 controls the electric motor 32 (drive circuit 10e) so that the steering angle θs matches the target value θd. For example, if the current steering angle θs is "0°", the steering assist ECU 10 gradually increases (or decreases) the torque Tm applied from the electric motor 32 to the steering shaft 312 from "0", and holds the torque Tm when the steering angle θs matches the target value θd. In the following explanation, this torque value will be referred to as "lane tracing torque Td". In this state, since the driver is not steering, the steering torque Ts is approximately "0", and the shaft torque Tsft applied to the steering shaft 312 is "Td".

[0031] The operating mode in which lane tracing control can be performed only when the driver is lightly gripping the steering wheel switch is referred to as hands-on mode (normal mode). On the other hand, the operating mode in which lane tracing control can be performed even when the driver is not gripping the steering wheel switch is referred to as hands-off mode. For example, in hands-on mode, if the duration of time the driver is looking ahead exceeds a threshold, the system switches to hands-off mode. In hands-off mode, if the duration of time the driver is not looking ahead exceeds a threshold, the system switches to hands-on mode.

[0032] <Steering Override Control> When the driver rotates the steering wheel SW (SOR) while the steering angle θs matches the target value θd due to lane tracing control, the vehicle control device 1 performs the following steering override control. In the following description, the steering angle θs (angle value) when the steering is performed will be denoted as "θsor". The steering torque Ts (torque value) when the steering is performed will be denoted as "Tsor".

[0033] The steering support ECU 10 sequentially acquires various information from the steering sensor 33 while performing lane tracing control. The steering support ECU 10 controls the electric motor 32 based on the steering torque Ts (=Tsor). Specifically, the steering support ECU 10 controls the electric motor 32 (drive circuit 10e) so that, in addition to the lane tracing torque Td, an assist torque ΔTa is applied to the steering shaft 312 as torque Tm. Here, the steering support ECU 10 determines the assist torque ΔTa (torque value) by referring to the table TBsor shown in Figure 5. Table TBsor consists of table TBH, table TBM, and table TBL. The steering support ECU 10 selects one of these tables as follows.

[0034] The steering support ECU 10 identifies the type of the current driving scene SCN based on the information (vs, Ts) obtained from the on-board sensor 20 and the steering sensor 33. If the current driving scene SCN corresponds to driving scene SH, where steering override is frequent, the steering support ECU 10 determines the assist torque ΔTa by referring to table TBH (Figure 5). If the current driving scene SCN corresponds to driving scene SM, where steering override is moderate, the steering support ECU 10 determines the assist torque ΔTa by referring to table TBM. If the current driving scene corresponds to driving scene SL, where steering override is infrequent, the steering support ECU 10 determines the assist torque ΔTa by referring to table TBL. The steering support ECU 10 then changes the torque Tm applied from the electric motor 32 to the steering shaft 312 from "Td" to "Td+ΔTa".

[0035] In this embodiment, even when the vehicle is traveling on a highway (corresponding to driving scene SM or driving scene SL), if it falls under any of the driving scenes SH except "driving on a public road", the steering support ECU 10 will determine the assist torque ΔTa by referring to table TBH.

[0036] Here, as shown in Figure 5, in each table, the absolute value of the assist torque ΔTa is larger at low speed (v0) than at high speed (v1). Also, assuming that the speed vs in driving scene SH is the same as the speed vs in driving scene SM, the absolute value of the assist torque ΔTa in driving scene SM is smaller than the absolute value of the assist torque ΔTa in driving scene SH. Also, assuming that the speed vs in driving scene SM is the same as the speed vs in driving scene SL, the absolute value of the assist torque ΔTa in driving scene SL is smaller than the absolute value of the assist torque ΔTa in driving scene SM.

[0037] Figure 3 shows an example where the driver rotates the steering wheel switch to the right while the vehicle is turning to the right due to lane tracing control (θs=θd). In this example, the steering angle θs increases from "θd" to "θsorR", as shown by the solid line in Figure 4(A). The steering support ECU 10 recognizes the current driving scene SCN based on the information obtained from the on-board sensor 20 and the steering sensor 33. The steering support ECU 10 then selects a table (Figure 5) corresponding to the driving scene SCN. For example, if the current driving scene SCN corresponds to driving scene SH, the steering support ECU 10 selects table TBH. In this example, since the steering wheel switch is rotated to the right, the steering torque Ts increases from "0". Therefore, as shown by the solid line in Figure 5(A), the assist torque ΔTa increases with the increase in steering torque Ts. In other words, as shown by the solid line in Figure 4(B), the clockwise (positive) torque Tm applied from the electric motor 32 to the steering shaft 312 is corrected (increased) from "Td" to "Td+ΔTa". In other words, the clockwise rotation operation of the steering wheel switch is assisted by the electric motor 32. As a result, the steering torque Ts is reduced. That is, the steering wheel switch feels lighter (heavier) to operate compared to when the torque Tm applied from the electric motor 32 to the steering shaft 312 is not corrected.

[0038] Furthermore, if the current driving scene SCN corresponds to driving scene SM, the steering assist ECU 10 selects table TBM. As shown by the solid line in Figure 5(B), the assist torque ΔTa increases with increasing steering torque Ts, but the amount of increase is smaller compared to driving scene SH. That is, the right-hand (positive) torque Tm applied from the electric motor 32 to the steering shaft 312 increases, but the amount of increase is slightly smaller compared to driving scene SH. Therefore, the steering torque Ts is slightly larger compared to driving scene SH. In other words, the operating feel (weight) of the steering wheel SW is moderate.

[0039] Furthermore, if the current driving scene SCN corresponds to driving scene SL, the steering assist ECU 10 selects table TBL. As shown by the solid line in Figure 5(C), the assist torque ΔTa increases with increasing steering torque Ts, but the amount of increase is smaller compared to driving scene SM. In other words, the rightward (positive) torque Tm applied from the electric motor 32 to the steering shaft 312 increases, but the amount of increase is smaller compared to driving scene SM. Therefore, the steering torque Ts is larger compared to driving scene SM. In other words, the steering wheel switch feels heavier to operate. To put it another way, the steering wheel switch is more stable.

[0040] In the example shown in Figure 3 above, the driver rotates the steering wheel switch clockwise. Conversely, let's explain an example where the driver rotates the steering wheel switch counterclockwise. In this example, as shown by the dashed line in Figure 4(A), the steering angle θs decreases from "θd" to "θsorL". The steering support ECU 10 recognizes the current driving scene SCN based on the information obtained from the on-board sensor 20 and the steering sensor 33. The steering support ECU 10 then selects a table (Figure 5) corresponding to the driving scene SCN. For example, if the current driving scene SCN corresponds to driving scene SH, the steering support ECU 10 selects table TBH. In this example, since the steering wheel switch is rotated counterclockwise, the steering torque Ts decreases from "0", as shown by the dashed line in Figure 4(C). Therefore, as shown by the dashed line in Figure 5(A), the assist torque ΔTa decreases along with the decrease in steering torque Ts. In other words, as shown by the dashed line in Figure 4(B), the clockwise (forward) torque Tm applied from the electric motor 32 to the steering shaft 312 is reduced. In this way, the steering torque Ts is reduced by the reduction in the output of the electric motor 32. That is, the steering wheel switch feels lighter to operate compared to the case where the torque Tm applied from the electric motor 32 to the steering shaft 312 is not corrected.

[0041] Furthermore, for example, if the current driving scene SCN corresponds to driving scene SL, the steering assist ECU 10 selects table TBL. As shown by the dashed line in Figure 5(C), the assist torque ΔTa decreases with decreasing steering torque Ts, but the amount of decrease is smaller compared to driving scene SH. In other words, the torque applied from the electric motor 32 to the steering shaft 312 in the clockwise direction (positive direction) decreases, but the amount of decrease is smaller compared to driving scene SH. Therefore, the steering torque Ts is larger compared to driving scene SH. In other words, the steering wheel SW feels heavier to operate. This means that the steering wheel SW is more stable.

[0042] Next, referring to Figure 6, we will describe the program PR1 that the CPU 10a (hereinafter simply referred to as "CPU") of the steering assistance ECU 10 executes to perform the steering override control described above.

[0043] When switch 25 is ON, the CPU starts executing program PR1 at a predetermined interval. The CPU starts executing program PR1 from step 100 and proceeds to step 101.

[0044] When the CPU proceeds to step 101, it determines whether the steering wheel switch is being rotated (whether or not the vehicle is being steered). For example, the CPU determines that the vehicle is being steered if the steering angle θs of the steering wheel switch increases or decreases by a small threshold Δθs from the state where it matches the target value θd in the lane tracing diagram. If the CPU determines that the vehicle is being steered (101: Yes), it proceeds to step 102. On the other hand, if the CPU determines that the vehicle is not being steered (101: No), it returns to step 101.

[0045] When the CPU proceeds to step 102, it acquires various information from the forward sensor and steering sensor 33 (touch sensor 333), and recognizes the current driving scene SCN based on this information. Then the CPU proceeds to step 103.

[0046] When the CPU proceeds to step 103, it determines whether the current driving scene SCN corresponds to driving scene SH (one of the options in Figure 5(A)). If the CPU determines that the current driving scene SCN corresponds to driving scene SH (103: Yes), it proceeds to step 105. On the other hand, if the CPU determines that the current driving scene SCN does not correspond to driving scene SH (103: No), it proceeds to step 104.

[0047] When the CPU proceeds to step 104, it determines whether the current driving scene SCN corresponds to driving scene SM (Figure 5(B)). If the CPU determines that the current driving scene SCN corresponds to driving scene SM (104; Yes), it proceeds to step 106. On the other hand, if the CPU determines that the current driving scene SCN does not correspond to driving scene SM (if the driving scene SCN corresponds to driving scene SL (Figure 5(C)) (104; No)), it proceeds to step 107.

[0048] As the CPU proceeds from step 103 to step 105, it refers to table TBH (Figure 5(A)) to correct the torque applied from the electric motor 32 to the steering shaft 312. Then, the CPU proceeds to step 108 and terminates the execution of program PR1.

[0049] As the CPU proceeds from step 104 to step 106, it refers to the table TBM (Figure 5(B)) to correct the torque applied from the electric motor 32 to the steering shaft 312. Then the CPU proceeds to step 108.

[0050] As the CPU proceeds from step 104 to step 107, it refers to table TBL (Figure 5(C)) to correct the torque applied from the electric motor 32 to the steering shaft 312. Then the CPU proceeds to step 108.

[0051] (Effect) As described above, when the driver steers while lane tracing control is being performed, the steering support ECU 10 determines the assist torque ΔTa to be applied to the steering shaft 312 according to the type of current driving scene SCN (SH, SM, SL). Therefore, according to this embodiment, a steering feel suitable for the driving scene SCN can be achieved.

[0052] It should be noted that the present invention is not limited to the embodiments described above, and various modifications can be adopted within the scope of the present invention.

[0053] <Modification 1> In the above embodiment, the steering support ECU 10 controls the electric motor 32 so that when the driver steers while lane tracing control is being performed, an assist torque ΔTa corresponding to the type of driving scene SCN is applied to the steering shaft 312. Alternatively (or in addition to this), the steering support ECU 10 may correct the target value θd determined based on the recognition result of the driving lane L. Specifically, the steering support ECU 10 adopts the value obtained by adding the correction value Δθd to the target value θd as the target value θdsor during steering override. That is, the steering support ECU 10 shifts the target value of the steering angle θs in the same direction as the steering direction by the driver. In this case, the correction value Δθd is determined based on a table similar to the table TBsor (Figure 5) used to determine the assist torque ΔTa described above. The absolute value of the correction value Δθd in driving scene SM is smaller than the absolute value of the correction value Δθd in driving scene SH, and the absolute value of the correction value Δθd in driving scene SL is smaller than the absolute value of the correction value Δθd in driving scene SM. In this way, the amount of reduction in steering torque Ts is adjusted according to the type of driving scene SCN. Therefore, according to this modified example, a steering feel suitable for driving scene SCN can be achieved.

[0054] <Modification 2> In the above embodiment, the steering shaft 312 is driven by the electric motor 32, but instead, the rack 314 may be driven by the electric motor 32. [Explanation of symbols]

[0055] 10...Steering assist ECU, 20...On-board sensors, 30...Steering system

Claims

1. A sensor that acquires information about the vehicle itself and information about targets present in the vicinity of the vehicle, A steering device comprising a steering mechanism that connects the steering wheel and steering wheels of the vehicle, and an electric motor that drives the steering mechanism, A processor that performs lane tracing control, which determines a target steering angle for the vehicle so that it moves along the lane it is traveling in, calculates a lane tracing torque which is the torque applied to the steering mechanism to make the actual steering angle of the vehicle match the target steering angle, and controls the electric motor so that the lane tracing torque is output, and is configured to perform steering override control, which controls the electric motor so that, in addition to the lane tracing torque, an assist torque corresponding to the rotation direction and steering torque of the steering wheel is applied to the steering mechanism when the steering wheel is rotated while the lane tracing control is being performed, A vehicle control device equipped with, The aforementioned processor, In a predetermined first driving scene while the lane tracing control is being performed, the electric motor is controlled so that the assist torque when the driver rotates the steering wheel matches a predetermined first target value. In a predetermined second driving scene in which the lane tracing control is being performed, and which is defined in advance as a driving scene in which the frequency of rotation of the steering wheel is lower than in the first driving scene, the electric motor is controlled so that the assist torque when the driver rotates the steering wheel matches a second target value which is smaller than the first target value. In a predetermined third driving scene during which the lane tracing control is being performed, and which is defined in advance as a driving scene in which the frequency of rotation of the steering wheel is lower than in the second driving scene, the electric motor is controlled so that the assist torque when the driver rotates the steering wheel matches a third target value that is smaller than the second target value. It is configured in such a way, The aforementioned first driving scene includes at least one of the following: a situation in which the turn signal is activated, a situation in which the vehicle is driving on an ordinary road, a situation in which the vehicle is driving in the vicinity of a construction zone, a situation in which an obstacle is detected, or a situation in which adaptive cruise control is being performed to follow the preceding vehicle. The second driving scene described above is a situation in which the vehicle is being driven in hands-on mode, in which lane tracing control can be performed only when the driver is holding the steering wheel. The third driving scene described above is a situation in which the vehicle is being driven in hands-off mode, in which lane tracing control can be performed even if the driver is not holding the steering wheel. The system includes a first to third table corresponding to the first, second, and third driving scenes, respectively. Each of the first to third tables includes a dataset corresponding to multiple vehicle speeds, and each dataset shows the relationship between the steering torque and the target value of the assist torque. In each table, the assist torque for the same steering torque is set such that the absolute value of the assist torque at high speed is smaller than the absolute value of the assist torque at low speed, and furthermore, the first to third tables are set such that, for the same vehicle speed and the same steering torque, the absolute value of the assist torque defined by the first table is greater than the absolute value of the assist torque defined by the second table, and the absolute value of the assist torque defined by the second table is greater than the absolute value of the assist torque defined by the third table. The processor selects one of the first to third tables according to the recognized driving scene, and determines the target value of the assist torque by referring to the dataset corresponding to the vehicle speed from the selected table. Vehicle control system.

2. An information acquisition step involves acquiring information about the vehicle itself and information about targets present in the vicinity of the vehicle. A lane trace control step involves determining a target steering angle for the vehicle so that it moves along the lane it is traveling in, calculating a lane trace torque which is the torque applied to the steering mechanism connecting the vehicle's steering wheel and steering wheels in order to make the actual steering angle of the vehicle match the target steering angle, and controlling the electric motor that drives the steering mechanism so that the lane trace torque is output. During the execution of the lane tracing control step, if the steering wheel is rotated, a steering override control step is performed to control the electric motor so that, in addition to the lane tracing torque, an assist torque corresponding to the rotation direction and steering torque of the steering wheel is applied to the steering mechanism. A vehicle control method including, The steering override control step is: The steps include controlling the electric motor so that the assist torque when the driver rotates the steering wheel matches a predetermined first target value during a predetermined first driving scene in which the lane tracing control step is being executed, In a predetermined second driving scene during which the lane tracing control step is being executed, the electric motor is controlled such that the assist torque when the driver rotates the steering wheel matches a second target value which is smaller than the first target value, in the second driving scene which is predetermined as a driving scene in which the frequency of rotation of the steering wheel is lower than that of the first driving scene. In a predetermined third driving scene during which the lane tracing control step is being executed, the third driving scene is defined in advance as a driving scene in which the frequency of rotation of the steering wheel is lower than that of the second driving scene, the step of controlling the electric motor so that the assist torque when the driver rotates the steering wheel matches a third target value that is smaller than the second target value, It is configured to include, The aforementioned first driving scene includes at least one of the following: a situation in which the turn signal is activated, a situation in which the vehicle is driving on an ordinary road, a situation in which the vehicle is driving in the vicinity of a construction zone, a situation in which an obstacle is detected, or a situation in which adaptive cruise control is being performed to follow the preceding vehicle. The second driving scene is a situation in which the vehicle is being driven in hands-on mode, in which the lane tracing control step can be executed only when the driver is holding the steering wheel. The third driving scene is a situation in which the vehicle is being driven in hands-off mode, in which the lane tracing control step can be executed even if the driver is not holding the steering wheel. The steering override control step includes selecting a table from among the first to third tables, each corresponding to the first, second, and third driving scenes, which show the relationship between the steering torque and the target value of the assist torque and include a dataset corresponding to a plurality of vehicle speeds, the step of selecting a table corresponding to the recognized driving scene, and determining the target value of the assist torque corresponding to the vehicle speed by referring to the selected table. In each table, the assist torque for the same steering torque is set such that the absolute value of the assist torque at high speed is smaller than the absolute value of the assist torque at low speed, and furthermore, the first to third tables are set such that, for the same vehicle speed and the same steering torque, the absolute value of the assist torque defined by the first table is greater than the absolute value of the assist torque defined by the second table, and the absolute value of the assist torque defined by the second table is greater than the absolute value of the assist torque defined by the third table. Vehicle control method.

3. The computer installed in the vehicle, An information acquisition step involves acquiring information about the vehicle itself and information about targets present in the vicinity of the vehicle. A lane trace control step involves determining a target steering angle for the vehicle so that it moves along the lane it is traveling in, calculating a lane trace torque which is the torque applied to the steering mechanism connecting the vehicle's steering wheel and steering wheels in order to make the actual steering angle of the vehicle match the target steering angle, and controlling the electric motor that drives the steering mechanism so that the lane trace torque is output. During the execution of the lane tracing control step, if the steering wheel is rotated, a steering override control step is performed to control the electric motor so that, in addition to the lane tracing torque, an assist torque corresponding to the rotation direction and steering torque of the steering wheel is applied to the steering mechanism. A vehicle control program that causes the execution of The steering override control step is: The steps include controlling the electric motor so that the assist torque when the driver rotates the steering wheel matches a predetermined first target value during a predetermined first driving scene in which the lane tracing control step is being executed, In a predetermined second driving scene during which the lane tracing control step is being executed, the electric motor is controlled such that the assist torque when the driver rotates the steering wheel matches a second target value which is smaller than the first target value, in the second driving scene which is predetermined as a driving scene in which the frequency of rotation of the steering wheel is lower than that of the first driving scene. In a predetermined third driving scene during which the lane tracing control step is being executed, the third driving scene is defined in advance as a driving scene in which the frequency of rotation of the steering wheel is lower than that of the second driving scene, the step of controlling the electric motor so that the assist torque when the driver rotates the steering wheel matches a third target value that is smaller than the second target value, It is configured to include, The aforementioned first driving scene includes at least one of the following: a situation in which the turn signal is activated, a situation in which the vehicle is driving on an ordinary road, a situation in which the vehicle is driving in the vicinity of a construction zone, a situation in which an obstacle is detected, or a situation in which adaptive cruise control is being performed to follow the preceding vehicle. The second driving scene is a situation in which the vehicle is being driven in hands-on mode, in which the lane tracing control step can be executed only when the driver is holding the steering wheel. The third driving scene is a situation in which the vehicle is being driven in hands-off mode, in which the lane tracing control step can be executed even if the driver is not holding the steering wheel. The steering override control step includes selecting a table from among the first to third tables, each corresponding to the first, second, and third driving scenes, which show the relationship between the steering torque and the target value of the assist torque and include a dataset corresponding to a plurality of vehicle speeds, the step of selecting a table corresponding to the recognized driving scene, and determining the target value of the assist torque corresponding to the vehicle speed by referring to the selected table. In each table, the assist torque for the same steering torque is set such that the absolute value of the assist torque at high speed is smaller than the absolute value of the assist torque at low speed, and furthermore, the first to third tables are set such that, for the same vehicle speed and the same steering torque, the absolute value of the assist torque defined by the first table is greater than the absolute value of the assist torque defined by the second table, and the absolute value of the assist torque defined by the second table is greater than the absolute value of the assist torque defined by the third table. Vehicle control program.

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