Vehicle control device, vehicle control method, and program

Abstract

To provide a vehicle control device that can execute lateral position control in accordance with a driver's characteristics on a curve road and can reduce a risk that the lateral position control gives discomfort and anxiety to the driver.SOLUTION: A vehicle control device can execute lateral position control to control turning wheels such that a target turning angle for a vehicle to maintain a predetermined target lateral position in a travel area where the vehicle runs coincides with a turning angle of the turning wheels of the vehicle. In a non-execution period in which the lateral position control is not executed, the vehicle control device learns the driver's characteristics on a curve road based on an index value that indicates a relationship between the target lateral position and a steering traveling direction that indicates a traveling direction of the vehicle by a steering operation of the driver to a steering wheel and changes, based on the learned driver's characteristics, a control parameter used in the lateral position control.SELECTED DRAWING: Figure 5

Description

Technical Field

[0001] The present invention relates to a vehicle control device that executes lateral position control for controlling a steering wheel so that a vehicle travels while maintaining a target lateral position in a travel region, a vehicle control method in which a computer mounted on a vehicle executes the lateral position control, and a program for causing the computer to execute the lateral position control.

Background Art

[0002] Conventionally, there has been known a vehicle control device that executes lateral position control (lane keeping control) for controlling a steering wheel so that a vehicle travels while maintaining a target lateral position in a travel region. For example, when the reliability of the recognition result of a dividing line that divides a travel region is low, the vehicle control device described in Patent Document 1 (hereinafter referred to as "conventional device") reduces the responsiveness of the lateral position control by reducing control parameters (upper limit values of a target steering angle and an upper limit value of a target steering angular velocity) used in the lateral position control.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

[0004] When a vehicle travels on a curved road, characteristics tend to differ for each driver. For example, there are drivers who have characteristics (inner characteristics) of causing a vehicle to travel on the inner side of a curved road, and there are also drivers who have characteristics (outer characteristics) of causing a vehicle to travel on the outer side of a curved road.

[0005] The conventional device can execute lateral position control according to the reliability of the recognition result of a dividing line, but cannot execute lateral position control according to the characteristics of a driver with respect to a curved road. Lateral position control that does not match the characteristics of a driver may give the driver a sense of discomfort and uneasiness.

[0006] This invention was made to address the aforementioned problems. Specifically, it aims to provide a vehicle control device that performs lateral position control tailored to the driver's characteristics on curved roads, thereby reducing the possibility that lateral position control may cause discomfort and anxiety to the driver.

[0007] The vehicle control device of the present invention (hereinafter also referred to as the "device of the present invention") is In a vehicle control device (10) capable of performing lateral position control, the steering wheel is controlled such that the steering angle (θt) of the vehicle's steering wheel coincides with the target steering angle (θt) for the vehicle to maintain a predetermined target lateral position (Ltgt) in a driving area (TA) on which the vehicle (VA) travels, The aforementioned vehicle control device is During the non-execution period when the lateral position control is not performed, the driver's characteristics on a curved road are learned based on an index value representing the relationship between the steering direction, which represents the direction of travel of the vehicle due to the driver's steering operation on the steering wheel, and the target lateral position (steps 430 to 445, step 455, step 460), Based on the learned driver characteristics, the control parameters used in the lateral position control are changed (steps 525 to 535, steps 580 to 590). It is structured in this way.

[0008] The present invention's device learns the driver's characteristics on curved roads based on an index value representing the relationship between the steering direction and the target lateral position during non-operational periods. Then, the device modifies the control parameters used for lateral position control based on the learned driver characteristics. As a result, lateral position control is performed using control parameters that match the driver's characteristics, thus reducing the possibility that lateral position control may cause discomfort and anxiety to the driver.

[0009] For example, the device of the present invention determines the driver's characteristics as "inward characteristics" if the steering direction during the non-execution period tends to be inward of the target lateral position, and determines the driver's characteristics as "outward characteristics" if the steering direction during the non-execution period tends to be outward of the target lateral position.

[0010] The control parameters include the control threshold angle and the control gain. <Control ETC angle> During the period in which lateral position control is being performed, if the difference between the target steering angle and the steering angle becomes greater than or equal to the control threshold angle, the device of the present invention controls the steering wheels so that the steering angle matches the target steering angle. Drivers with an inward steering characteristic tend to initiate steering operations on curves earlier than drivers with an outward steering characteristic. Therefore, the present invention reduces the control threshold angle when the driver has an inward steering characteristic compared to when the driver has an outward steering characteristic. This reduces the possibility that drivers with an inward steering characteristic may experience discomfort and anxiety regarding lateral position control due to the delayed initiation of steering wheel control via lateral position control.

[0011] <Control Gain> The present invention obtains the target steering angle θtgt based on the vehicle's position relative to the target lateral position and the control gain (see equation (1) described later). As the control gain increases, the target steering angle tends to increase, and the difference between the target steering angle and the steering angle tends to exceed the control threshold angle. For this reason, the present invention increases the control gain when the driver's characteristics are inside characteristics compared to when the driver's characteristics are outside characteristics. [Brief explanation of the drawing]

[0012] [Figure 1] This is a schematic system configuration diagram of a vehicle control device according to an embodiment of the present invention. [Figure 2] This is an explanatory diagram of steering assistance control performed by a vehicle control device according to an embodiment of the present invention. [Figure 3] Figure 1 is a flowchart showing the LTA start / end determination routine executed by the CPU of the vehicle control ECU. [Figure 4] Figure 1 is a flowchart showing the steering assistance control routine executed by the CPU of the vehicle control ECU. [Figure 5]Figure 1 is a flowchart showing the LTA routine executed by the CPU of the vehicle control ECU. [Figure 6] This flowchart shows a portion of the LTA routine executed by the CPU of a vehicle control ECU according to a first modified embodiment of the present invention. [Modes for carrying out the invention]

[0013] As shown in Figure 1, the vehicle control device (hereinafter referred to as "this device") 10 according to this embodiment is applied to a vehicle VA and comprises the components shown in Figure 1.

[0014] The vehicle control ECU20 is an ECU capable of performing steering assist control and lateral position control, and will be referred to as "ECU20" below.

[0015] Steering assist control is performed during non-execution periods when lateral position control is not being performed. Specifically, steering assist control applies a steering reaction force Fs to the steering wheel switch in the opposite direction to the steering operation performed by the driver on the steering wheel switch, prompting the driver to perform a steering operation to move the vehicle VA to the target lateral position Ltgt (see Figure 2) in the driving region TA (see Figure 2). In this way, steering assist control can support the driver's steering operation.

[0016] Lateral position control is a control system that controls the steering wheels of the vehicle's vehicle array (VA) so that the VA maintains its target lateral position Ltgt while driving, even without the driver operating the steering wheel switch. Lateral position control is sometimes referred to as "lane keeping control" or "LTA (Lane Tracing Assist)".

[0017] The ECU 20 is an electronic control unit having a microcomputer as a main component. The ECU 20 is also referred to as a controller or a computer. The microcomputer includes a CPU (processor), a ROM, a RAM, an interface (I / F), etc. The CPU realizes various functions by executing instructions (routines) stored in a memory (ROM). At least one function realized by the ECU 20 may be realized by a plurality of ECUs.

[0018] The camera 22 acquires image data by photographing the scenery in front of the vehicle VA. The camera 22 acquires boundary information based on the image data. The boundary information includes the position of the boundary BL that defines the travel region TA with respect to the vehicle VA. Examples of the boundary BL include white lines on the road, guardrails, curbstones, and walls. The camera 22 transmits the image data and the boundary information to the ECU 20.

[0019] The vehicle speed sensor 24 detects a vehicle speed Vs representing the speed of the vehicle VA. The steering angle sensor 26 detects a steering angle θt of the steering wheel. The steering torque sensor 28 detects a steering torque Tr applied to a steering shaft SS connected to the steering wheel SW. The ECU 20 acquires the detection values of these sensors 24 to 28.

[0020] The LTA switch 30 is disposed on the steering wheel SW. When the LTA is not being executed, the driver operates the LTA switch 30 to start the LTA. When the LTA is being executed, the driver operates the LTA switch 30 to terminate the LTA. The ECU 20 detects the driver's operation on the LTA switch 30.

[0021] The steering motor 40 is incorporated into the steering mechanism 42. The steering mechanism 42 is a mechanism for steering the steering wheels in response to steering operations on the steering wheel SW. When LTA is being performed, the steering motor 40 generates torque in the steering mechanism 42 so that the steering angle θt matches the target steering angle θtgt. When LTA is not being performed, the steering motor 40 generates torque in the steering mechanism 42 to generate a steering reaction force Fs on the steering wheel SW.

[0022] The memory device 44 is, for example, a non-volatile memory device. The memory device 44 has a steering reaction force memory unit 46. The steering reaction force memory unit 46 is a memory area that stores the steering reaction force Fs during non-execution periods when LTA is not being performed.

[0023] (Steering assist control) Steering assist control will be explained with reference to Figure 2. The ECU20 recognizes the right boundary RBL, which defines the right edge of the driving area TA, and the left boundary LBL, which defines the left edge of the driving area TA, based on boundary information. The ECU20 sets the target lateral position Ltgt at a predetermined lateral position in the width direction of the driving area TA determined by the right boundary RBL and the left boundary LBL.

[0024] The ECU20 obtains the target steering angle θtgt based on the position of the vehicle VA relative to the target lateral position Ltgt. More specifically, the ECU20 obtains the target steering angle θtgt based on the following equation (1). θtgt=k1·CL+k2·θL+k3·dL …(1) In equation (1), k1, k2, and k3 are control gains and are constants.

[0025] CL represents the curvature of the target horizontal position Ltgt. When curving to the left, the value of curvature CL is negative, and when curving to the right, the value of curvature CL is positive. θL is the angle (yaw angle) between the direction of the target lateral position Ltgt and the longitudinal direction of the vehicle VA. The yaw angle θL is negative if the longitudinal direction of the vehicle VA is to the left of the direction of the target lateral position Ltgt, and positive if it is to the right. dL is the distance (lateral deviation) in the width direction of the driving area TA between a "reference point pre-set at a predetermined position on the vehicle VA" and the target lateral position Ltgt. The lateral deviation dL is a negative value when the reference point P is located to the left of the target lateral position Ltgt, and a positive value when it is located to the right.

[0026] The ECU20 determines whether the inside condition and the outside condition are met based on the subtracted value dθ, which is obtained by subtracting the target steering angle θtgt from the current steering angle θt. Internal condition: The absolute value of the subtraction value dθ is greater than or equal to the threshold angle dθth, and the product of the target steering angle θtgt and the subtraction value dθ is positive. External condition: The absolute value of the subtraction value dθ is greater than or equal to the threshold angle dθth, and the product of the target steering angle θtgt and the subtraction value dθ is negative.

[0027] If the inside condition is met, the ECU20 determines that the direction of travel of the vehicle VA due to the driver's steering operation (hereinafter referred to as the "steering direction of travel") is inside the target lateral position Ltgt. If the outside condition is met, the ECU20 determines that the steering direction of travel is outside the target lateral position Ltgt.

[0028] When the inside condition is met, the ECU20 increases the steering reaction force Fs compared to when neither the inside nor outside condition is met. This makes it more difficult for the driver to steer in the direction of the inside of a curve compared to normal conditions. Therefore, the steering reaction force Fs can encourage the driver to steer the vehicle VA to the target lateral position Ltgt.

[0029] When the outside condition is met, the ECU20 reduces the steering reaction force Fs compared to when neither the inside nor outside condition is met. This makes it easier for the driver to steer towards the inside of a curve compared to normal conditions. Therefore, the steering reaction force Fs can encourage the driver to steer the vehicle VA to the target lateral position Ltgt.

[0030] The inside condition is met when vehicle VA travels along the path Rin shown in Figure 2, which is inside the target lateral position Ltgt. In this case, a larger steering reaction force Fsin is generated than under normal conditions.

[0031] The outside condition is met when vehicle VA travels along the path Rou shown in Figure 2, which is outside the target lateral position Ltgt. In this case, a larger steering reaction force Fsou than usual is generated.

[0032] As described above, the magnitude of the steering reaction force Fs increases when the steering direction is inward of the target lateral position Ltgt, and decreases when the steering direction is outward of the target lateral position Ltgt. Therefore, the steering reaction force Fs serves as an index value representing the relationship between the steering direction and the target lateral position Ltgt.

[0033] (Horizontal position control) When LTA is being executed, the ECU 20 obtains the target steering angle θtgt using equation (1) above and obtains the subtracted value dθ (dθ = θt - θtgt). From the time the control condition that the absolute value of the subtracted value dθ is greater than or equal to the control threshold angle θtth is met until both the target steering angle θtgt and the subtracted value dθ become "0", the ECU 20 controls the steering motor 40 so that the steering angle θt matches the target steering angle θtgt. If the control condition is not met, the ECU 20 does not control the steering motor 40 so that the steering angle θt matches the target steering angle θtgt and effectively does not perform lateral position control.

[0034] The ECU20 terminates the LTA if the magnitude of the steering torque Trs becomes greater than or equal to the threshold torque Trth during LTA execution. During LTA execution, if the steering angle θt is changed, the steering angle of the steering wheel is changed to the angle corresponding to the changed steering angle θt. The steering torque Trs is obtained by subtracting the steering torque Tr from the torque applied by the steering motor 40 to the steering shaft SS.

[0035] (Summary of operation) The ECU 20 of this device 10 learns the driver's characteristics on curved roads based on an index value (steering reaction force Fs) that represents the relationship between the steering direction and the target lateral position Ltgt during periods when LTA is not being performed. In detail, the ECU 20 learns whether the driver's characteristics are inside characteristics, outside characteristics, or normal characteristics.

[0036] The ECU20 modifies control parameters based on the learned driver characteristics. The control parameters include the control threshold angle θtth and the control gains k1, k2, and k3 in equation (1) above.

[0037] <Assuming the driver's characteristics are typical> The ECU20 sets the control threshold angle θtth to "θtmi" and the control gains k1, k2, and k3 to "k1mi", "k2mi", and "k3mi".

[0038] <When the driver's characteristics are such that they are inward-facing> The ECU20 sets the control threshold angle θtth to "θtin" and the control gains k1, k2, and k3 to "k1in", "k2in", and "k3in". Note that θtin is set to a smaller value than θtmi. Furthermore, k1in, k2in, and k3in are set to values ​​larger than k1mi, k2mi, and k3mi, respectively. When the driver exhibits an inward tendency, the control threshold angle θtth becomes smaller than normal, and the control gains (k1, k2, and k3) become larger than normal. As a result, the ECU20 can perform lateral position control that matches the inward tendency, thereby reducing the possibility that lateral position control may cause discomfort and anxiety to the driver.

[0039] <When the driver's characteristics are external characteristics> ECU20 sets the control threshold angle θtth to "θtou" and the control gains k1, k2, and k3 to "k1ou", "k2ou", and "k3ou". Note that θtou is set to a value larger than θtmi. Further, k1ou, k2ou, and k3ou are set to values smaller than k1mi, k2mi, and k3mi, respectively. When the driver has an outer characteristic, the control threshold angle θtth becomes larger than normal, and the control gains (k1, k2, and k3) become smaller than normal. Thereby, the ECU20 can execute lateral position control suitable for the outer characteristic, and thus the possibility that the lateral position control gives the driver discomfort and uneasiness can be reduced.

[0040] (Specific operation) <LTA start / end determination routine> The CPU of the ECU20 executes the LTA start / end determination routine shown by the flowchart in FIG. 3 every time a predetermined time elapses.

[0041] Therefore, at a predetermined timing, the CPU starts processing from step 300 in FIG. 3 and proceeds to step 305. At step 305, the CPU determines whether the value of the execution flag Xexe is "0".

[0042] The value of the execution flag Xexe is set to "1" when the LTA starts and set to "0" when the LTA ends. Note that the value of the execution flag Xexe is set to "0" in the initial routine.

[0043] When the value of the execution flag Xexe is "0", the CPU determines "Yes" at step 305 and proceeds to step 310. At step 310, the CPU determines whether the LTA switch 30 has been operated.

[0044] When the LTA switch 30 has not been operated, the CPU determines "No" at step 310, proceeds to step 395, and temporarily ends this routine.

[0045] If the LTA switch 30 is operated, the CPU determines "Yes" in step 310 and proceeds to step 315. In step 315, the CPU sets the value of the execution flag Xexe to "1" and the value of the control flag Xcon to "0". The value of the control flag Xcon is set to "1" when the steering motor 40 is actually controlled in LTA, and to "0" when the steering motor 40 is not actually controlled in LTA. After that, the CPU proceeds to step 395 and terminates this routine.

[0046] If the value of the execution flag Xexe is "1" when the CPU proceeds to step 305, the CPU determines "No" in step 305 and proceeds to step 320. In step 320, the CPU determines whether or not the LTA switch 30 has been operated.

[0047] If the LTA switch 30 is operated, the CPU determines "Yes" in step 320 and proceeds to step 325. In step 325, the CPU sets the value of the execution flag Xexe to "0". After that, the CPU proceeds to step 395 and terminates this routine.

[0048] If the LTA switch 30 is not operated, the CPU determines "No" in step 320 and proceeds to step 330. In step 330, the CPU determines whether the magnitude of the steering torque Trs is greater than or equal to the threshold torque Trth.

[0049] If the steering torque Trs is greater than or equal to the threshold torque Trth, the CPU determines "Yes" in step 330 and sets the value of the execution flag Xexe to "0" in step 325. After that, the CPU proceeds to step 395 and terminates this routine.

[0050] If the steering torque Trs is less than the threshold torque Trth, the CPU determines "No" in step 330 and proceeds to step 395 to terminate this routine.

[0051] <Steering Assist Control Routine> The CPU of ECU20 executes the steering assistance control routine shown in the flowchart in Figure 4 at predetermined intervals.

[0052] Therefore, at a predetermined time, the CPU starts processing from step 400 in Figure 4 and proceeds to step 405. In step 405, the CPU determines whether the value of the execution flag Xexe is "0".

[0053] If the value of the execution flag Xexe is "0", the CPU determines "Yes" in step 405 and executes steps 410 through 430 in order.

[0054] Step 410: The CPU identifies the boundary BL based on the boundary information. Step 415: The CPU sets the target lateral position Ltgt at a predetermined lateral position in the travel area TA determined by the boundary BL. Step 420: The CPU obtains the target steering angle θtgt based on equation (1) above. Step 425: The CPU obtains the subtracted value dθ by subtracting the target steering angle θtgt from the steering angle θt. Step 430: The CPU determines whether the internal condition is met.

[0055] If the internal condition is not met, the CPU determines "No" in step 430 and proceeds to step 435. In step 435, the CPU determines whether or not the external condition is met.

[0056] If the external condition is not met, the CPU determines "No" in step 435 and proceeds to step 440. In step 440, the CPU sets the steering reaction force Fs to "Fsmi". After that, the CPU executes steps 445 and 450.

[0057] Step 445: The CPU stores the steering reaction force Fs in the steering reaction force memory unit 46. Step 450: The CPU controls the steering motor 40 so that a steering reaction force Fs is generated in the opposite direction to the steering operation performed by the driver on the steering wheel SW. After that, the CPU proceeds to step 495 and terminates this routine.

[0058] If the internal condition is met when the CPU proceeds to step 430, the CPU determines "Yes" in step 430 and proceeds to step 455. In step 455, the CPU sets the steering reaction force Fs to "Fsin". Note that Fsin is set to a value greater than Fsmi. After that, the CPU executes steps 445 and 450, and proceeds to step 495 to terminate this routine.

[0059] If the external condition is met when the CPU proceeds to step 435, the CPU determines "Yes" in step 435 and proceeds to step 460. In step 460, the CPU sets the steering reaction force Fs to "Fsou". Note that Fsou is set to a smaller value than Fsmi. After that, the CPU executes steps 445 and 450, and proceeds to step 495 to terminate this routine.

[0060] If the value of the execution flag Xexe is "1" when the CPU proceeds to step 405, the CPU determines "No" in step 405 and proceeds to step 495 to terminate this routine.

[0061] <LTAルーチン> The CPU of ECU20 executes the LTA routine, as shown in the flowchart in Figure 5, at predetermined intervals.

[0062] Therefore, at a predetermined time, the CPU starts processing from step 500 in Figure 5 and proceeds to step 505. In step 505, the CPU determines whether the value of the execution flag Xexe is "1".

[0063] If the value of the execution flag Xexe is "0", the CPU determines "No" in step 505 and proceeds to step 595, terminating this routine.

[0064] If the value of the execution flag Xexe is "1", the CPU determines "Yes" in step 505 and executes steps 510 through 530.

[0065] Step 510: The CPU identifies the boundary BL. Step 515: The CPU sets the target lateral position Ltgt. Step 520: The CPU reads the steering reaction force Fs from the steering reaction force memory unit 46.

[0066] Step 525: The CPU identifies the driver's characteristics based on the steering reaction force Fs that it has read. In detail, the CPU obtains the larger of the two stored Fsin and Fsou values ​​in the steering reaction force memory unit 46 as the memory count N. If the number of stored Fsin values ​​is large and the memory count Nm is greater than or equal to the threshold Nmth, the CPU identifies the driver's characteristics as inside characteristics. If the number of stored Fsou values ​​is large and the memory count Nm is greater than or equal to the threshold Nmth, the CPU identifies the driver's characteristics as outside characteristics. If the memory count Nm is less than the threshold Nmth, the CPU identifies the driver's characteristics as normal characteristics.

[0067] Step 530: The CPU determines whether the driver's characteristics are internal characteristics or not.

[0068] If the driver's characteristics are internal characteristics, the CPU determines "Yes" in step 530 and executes steps 535 to 550. Step 535: The CPU sets the control gains k1, k2, and k3 to "k1in", "k2in", and "k3in", respectively, and sets the control threshold angle θtth to "θtin". Step 540: The CPU obtains the target steering angle θtgt based on equation (1) above. Step 545: The CPU obtains the subtracted value dθ. Step 550: The CPU determines whether the value of the control flag Xcon is "0".

[0069] If the value of the control flag Xcon is "0", the CPU determines "Yes" in step 550 and proceeds to step 555. In step 555, the CPU determines whether the magnitude of the subtraction value dθ is greater than or equal to the control threshold angle θtth.

[0070] If the magnitude of the subtraction value dθ is less than the control threshold angle θtth, the CPU determines "No" in step 555 and proceeds to step 595 to terminate this routine.

[0071] If the magnitude of the subtraction value dθ is greater than or equal to the control threshold angle θtth, the CPU determines "Yes" in step 555 and executes steps 560 and 565. Step 560: The CPU sets the value of the control flag Xcon to "1". Step 565: The CPU controls the steering motor 40 so that the steering angle θt matches the target steering angle θtgt. After that, the CPU proceeds to step 595 and terminates this routine.

[0072] If the value of the control flag Xcon is "1" when the CPU proceeds to step 550, the CPU determines "No" in step 550 and proceeds to step 570. In step 570, the CPU determines whether both the target steering angle θtgt and the subtraction value dθ are "0".

[0073] If at least one of the target steering angle θtgt and the subtraction value dθ is not "0", the CPU determines "No" in step 570 and proceeds to step 565.

[0074] If both the target steering angle θtgt and the subtraction value dθ are "0", the CPU determines "Yes" in step 570 and proceeds to step 575. In step 575, the CPU sets the value of the control flag Xcon to "0". After that, the CPU proceeds to step 595 and terminates this routine.

[0075] If the driver's characteristics are not inside characteristics when the CPU proceeds to step 530, the CPU determines "No" in step 530 and proceeds to step 580. In step 580, the CPU determines whether or not the driver's characteristics are outside characteristics.

[0076] If the driver's characteristics are external characteristics, the CPU determines "Yes" in step 580 and proceeds to step 585. In step 585, the CPU sets the control gains k1, k2, and k3 to "k1ou", "k2ou", and "k3ou" respectively, and sets the control threshold angle θtth to "θtou". After that, the CPU proceeds to step 540.

[0077] If the driver's characteristics are not outside characteristics when the CPU proceeds to step 580 (i.e., the driver's characteristics are normal characteristics), the CPU determines "Yes" in step 580 and proceeds to step 590. In step 590, the CPU sets the control gains k1, k2, and k3 to "k1mi", "k2mi", and "k3mi", respectively, and sets the control threshold angle θtth to "θtmi". After that, the CPU proceeds to step 540.

[0078] As explained above, the CPU learns the driver's characteristics based on the steering reaction force Fs and modifies the control parameters to match the driver's characteristics. This allows the CPU to perform LTA tailored to the driver's characteristics, reducing the possibility that LTA may cause anxiety and discomfort to the driver.

[0079] The present invention is not limited to the embodiments described above, and various modifications of the present invention can be adopted.

[0080] (First variation) In this modified example, the CPU of the ECU20 stores both the steering reaction force Fs and the steering torque Tr in the steering reaction force memory unit 46 during periods when LTA is not being executed. Based on the steering reaction force Fs and the steering torque Tr, the CPU obtains the number of steering inputs Ns in which the driver steers the steering wheel SW against the steering reaction force Fs during the period when the inside condition is met. If the number of steering inputs Ns is equal to or greater than the threshold number Nsth, the CPU sets the threshold torque Trth to "Trb", which is smaller than the normal value (Tra).

[0081] When the inside condition is met, the steering reaction force Fs is increased to make it difficult to steer in the direction of the inside of the curve. When the number of steering inputs Ns exceeds the threshold number Nsth, it is highly likely that the driver is performing steering inputs to keep the vehicle VA on the inside of the curve against this steering reaction force Fs for a threshold number of Nsth or more. Therefore, such a driver is likely to prefer driving on the inside of the curve. Accordingly, the CPU makes it easier to terminate the LTA than usual by setting the threshold torque Trth to "Trb". This allows the LTA to be executed in accordance with the driver's characteristics.

[0082] After the CPU executes step 520 shown in Figure 5, it executes steps 605 and 610 shown in Figure 6. Step 605: The CPU obtains the number of steering inputs Ns. Step 610: The CPU determines whether the number of steering inputs Ns is greater than or equal to the threshold number Nsth.

[0083] If the number of steering inputs Ns is less than the threshold number Nsth, the CPU determines "No" in step 610 and proceeds to step 615. In step 615, the CPU sets the threshold torque Trth to "Tra". After that, the CPU proceeds to step 525 as shown in Figure 5.

[0084] If the number of steering inputs Ns is equal to or greater than the threshold number Nsth, the CPU determines "Yes" in step 610 and proceeds to step 620. In step 620, the threshold torque Trth is set to "Trb". After that, the CPU proceeds to step 525 as shown in Figure 5.

[0085] (Second variation) The above embodiment is also applicable to steer-by-wire systems in which the steering wheel is mechanically separated from the steering wheels.

[0086] (Third variation) The steering reaction force Fs is used, but is not limited to, as an index value representing the relationship between the steering direction and the target lateral position Ltgt. For example, the curvature CL (or radius of curvature) of the target lateral position Ltgt and the steering angle θt may be used as index values ​​to identify the driver's characteristics.

[0087] (Fourth variation) The process of setting control parameters (control gains k1, k2, and k3, control threshold angle θtth, and threshold torque Trth) according to the driver's characteristics does not need to be performed every time the LTA routine shown in Figure 5 is executed. This process of setting control parameters only needs to be executed once when the LTA switch 30 is operated when the LTA is not running.

[0088] The device 10 is applicable to vehicles such as engine-powered vehicles, hybrid vehicles, plug-in hybrid vehicles, fuel cell vehicles, and electric vehicles. Furthermore, the control provided by the device 10 is also applicable when switching from autonomous driving to manual driving. Moreover, the present invention can also be considered as a non-temporary storage medium in which a program for realizing the functions of the device 10 is stored and which is readable by a computer. [Explanation of symbols]

[0089] 10...Vehicle control device, 20...Vehicle control ECU, 30...LTA switch, 40...Steering motor, 42...Steering mechanism, 46...Steering reaction force memory unit, SW...Steering wheel.

Claims

1. In a vehicle control device capable of performing lateral position control in which a vehicle travels while maintaining a predetermined target lateral position in a travel area on which the vehicle travels, if the magnitude of the difference between the target steering angle obtained based on the vehicle's position relative to the target lateral position and a control gain and the steering angle of the vehicle's steering wheels is greater than or equal to a control threshold angle, the steering wheels are controlled so that the target steering angle and the steering angle match, and if the magnitude of the difference is less than the control threshold angle, the steering wheels are not controlled. The aforementioned vehicle control device is During the non-execution period when the lateral position control is not being performed, a steering reaction force to prompt the driver to perform steering operations to move the vehicle to the target lateral position is obtained based on the relationship between the steering direction, which represents the direction of travel of the vehicle due to the driver's steering operation on the steering wheel, and the target lateral position, and the steering reaction force is applied to the steering wheel. Based on the steering reaction force, the driver determines whether the steering direction has an inward characteristic, where it tends to be inward of the target lateral position, or an outward characteristic, where it tends to be outward of the target lateral position. When the driver has the inner characteristics, the control gain is changed to make the control threshold angle smaller and the target steering angle larger compared to when the driver has the outer characteristics. A vehicle control device configured as follows.

2. In the vehicle control device according to claim 1, The aforementioned vehicle control device is If the steering torque applied by the driver to the steering wheel during the execution of the lateral position control exceeds a threshold torque, the lateral position control is terminated. If, during the non-execution period, the number of times the driver steers the steering wheel against the steering reaction force when the steering direction is inward from the target lateral position is greater than or equal to a predetermined threshold number, the threshold torque is reduced. A vehicle control device configured as follows.

3. A vehicle control method in which a computer mounted on a vehicle can perform lateral position control so that the vehicle maintains a predetermined target lateral position in a driving area on which the vehicle travels, wherein if the magnitude of the difference between a target steering angle obtained based on the vehicle's position and a control gain relative to the target lateral position and the steering angle of the vehicle's steering wheels is greater than or equal to a control threshold angle, the steering wheels are controlled so that the target steering angle and the steering angle match, and if the magnitude of the difference is less than the control threshold angle, the steering wheels are not controlled. The aforementioned vehicle control method is: The computer, during a non-execution period when the lateral position control is not being performed, obtains a steering reaction force to prompt the driver to perform steering operations to move the vehicle to the target lateral position, based on the relationship between the steering direction, which represents the direction of travel of the vehicle due to the driver's steering operation on the steering wheel, and the target lateral position, and applies the steering reaction force to the steering wheel. The steps include determining, based on the steering reaction force, whether the driver has an inward characteristic where the steering direction tends to be inward of the target lateral position, or an outward characteristic where the steering direction tends to be outward of the target lateral position, When the driver has the inner characteristics, the control gain is changed to make the control threshold angle smaller and the target steering angle larger compared to when the driver has the outer characteristics. A vehicle control method, including the following.

4. A program that can cause a computer mounted on a vehicle to perform lateral position control such that the steering wheel matches the target steering angle when the magnitude of the difference between the target steering angle obtained based on the vehicle's position and a control gain relative to the target lateral position and the steering angle of the vehicle's steering wheel is greater than or equal to a control threshold angle, and the steering wheel is not controlled when the magnitude of the difference is less than the control threshold angle, in order for the vehicle to travel while maintaining a predetermined target lateral position in a travel area on which the vehicle travels, The aforementioned program, During the non-execution period when the lateral position control is not being performed, a steering reaction force is obtained based on the relationship between the steering direction, which represents the direction of travel of the vehicle due to the driver's steering operation on the steering wheel, and the target lateral position, in order to prompt the driver to perform a steering operation to move the vehicle to the target lateral position, and the steering reaction force is applied to the steering wheel. A step in which the driver determines, based on the steering reaction force, whether the steering direction has an inward characteristic, where it tends to be inward of the target lateral position, or an outward characteristic, where it tends to be outward of the target lateral position. The steps include: when the driver has the inner characteristics, the control gain is modified to make the control threshold angle smaller and the target steering angle larger compared to when the driver has the outer characteristics; A program to be executed by the aforementioned computer.

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