Motor control device

Abstract

This motor control device includes: a manual steering command value generation unit that generates a manual steering command value by using an equation of motion of a reference model of a steering device; an integrated angle command value calculation unit that calculates an integrated angle command value by adding the manual steering command value to an automatic steering command value which is given when in a driving assistance mode; a control unit that performs angle control of an electric motor for steering angle control on the basis of the integrated angle command value; and a motion equation setting unit that changes the equation of motion in accordance with a lateral position of a vehicle reference position with respect to a travel lane and a time differential value of the actual steering angle or a time differential value of the manual steering command value.

Description

Motor control device

[0001] The present disclosure relates to a motor control device that controls the drive of an electric motor for steering angle control.

[0002] The following Patent Document 1 discloses that the target torque for the electric motor of an electric power steering device is calculated by adding a reference target torque, a lane keep torque (steering reaction force suppression torque), and a pseudo steering reaction force torque.

[0003] The reference target torque is a torque for assisting steering, and is set so that its absolute value increases as the absolute value of the driver input torque increases. The lane keeping torque (steering reaction suppression torque) is a torque for suppressing the steering reaction torque generated in the steering device. The pseudo steering reaction torque is a torque for correcting the lane keeping torque (steering reaction suppression torque) when a steering input from the driver occurs.

[0004] The pseudo steering reaction torque is the sum of the first pseudo steering reaction torque and the second pseudo steering reaction torque. The first pseudo steering reaction torque is set based on the driver input angle and the vehicle speed. The driver input angle means the steering angle provided by the driver and is a part of the steering angle (see paragraph 0046 of Patent Document 1). In other words, the driver input angle is different from the actual steering angle (real steering angle). The second pseudo steering reaction torque is set based on the driver input angular velocity and the vehicle speed.

[0005] JP 2012-6506 A International Publication No. 2023 / 286169 A

[0006] An object of the present disclosure is to provide a motor control device that can apply a steering reaction force to a driver in a new method in a driving assistance mode.

[0007] One embodiment of the present disclosure provides a motor control device including: a manual steering command value generation unit that generates a manual steering command value by utilizing an equation of motion of a reference model of a steering device; an integrated angle command value calculation unit that calculates an integrated angle command value by adding the manual steering command value to an automatic steering command value given in a driving assistance mode; a control unit that controls the angle of an electric motor for steering angle control based on the integrated angle command value; and an equation of motion setting unit that changes the equation of motion in accordance with the lateral position of a vehicle reference position with respect to the driving lane and the time derivative of the actual steering angle or the time derivative of the manual steering command value.

[0008] With this configuration, in the driving assistance mode, a steering reaction force can be applied to the driver in a novel manner.

[0009] The above and other objects, features, and advantages of the present disclosure will become apparent from the following description of the embodiments with reference to the accompanying drawings.

[0010] FIG. 1 is a schematic diagram showing the general configuration of an electric power steering system to which a motor control device according to an embodiment of the present disclosure is applied. FIG. 2 is a block diagram showing the electrical configuration of a motor control ECU. FIG. 3 is a diagram showing the lateral deviation e Ｌ Target virtual spring reaction force T ｔｂ，ｄ (e Ｌ ) is a graph showing an example of setting the lateral deviation e Ｌ 5 is a graph showing an example of setting the first virtual load spring stiffness coefficient kr and the second virtual load spring stiffness coefficient kg with respect to the lateral deviation e Ｌ First virtual load viscous damping coefficient cr(e Ｌ) and a graph showing an example of setting the second virtual load viscous damping coefficient cg. FIG. 6 is a schematic diagram showing an example of a reference EPS model used in the manual steering command value generation unit described in WO 2023 / 286169. FIG. 7 is a block diagram showing the configuration of the manual steering command value generation unit. FIG. 8A is a flowchart showing part of the procedure of the coefficient / weight setting process performed by the equation of motion setting unit in the driving assistance mode. FIG. 8B is a flowchart showing part of the procedure of the coefficient / weight setting process performed by the equation of motion setting unit in the driving assistance mode. FIG. 9 is a block diagram showing the configuration of the manual steering command value generation unit in first, third and fifth modified examples of the motor control ECU. FIG. 10 is a block diagram showing the configuration of the second modified example of the motor control ECU. FIG. 11A is a schematic diagram showing an example of the position of the vehicle when the vehicle reference position is to the right of the center of the lane, and FIG. 11B is a diagram showing the actual steering angle θ ｃ and the automatic steering command value θ ＡＤ，ｃｍｄ The signs of the two are positive, and the actual steering angle θ ｃ is the automatic steering command value θ ＡＤ，ｃｍｄ When the angle deviation Δθ is larger than Ａ 11C is a schematic diagram showing an example of the actual steering angle θ ｃ The sign of is negative, and the automatic steering command value θ ＡＤ，ｃｍｄ The angle deviation Δθ when the sign of is positive Ａ 12A is a schematic diagram showing an example of a coefficient / weight setting process performed by an equation of motion setting unit in the motor control ECU of FIG. 10 during driving assistance mode. FIG. 12B is a flowchart showing a part of the procedure for coefficient / weight setting performed by an equation of motion setting unit in the motor control ECU of FIG. 10 during driving assistance mode. FIG. 13 is a block diagram showing the configuration of a fourth modified example of the motor control ECU. FIG. 14A is a flowchart showing a part of the procedure for coefficient / weight setting performed by an equation of motion setting unit in the motor control ECU of FIG. 13 during driving assistance mode. FIG. 14B is a flowchart showing a part of the procedure for coefficient / weight setting performed by the equation of motion setting unit in the motor control ECU of FIG. 13 during driving assistance mode.

[0011] [Description of an embodiment of the present disclosure] One embodiment of the present disclosure provides a motor control device including: a manual steering command value generation unit that generates a manual steering command value by utilizing an equation of motion of a reference model of a steering device; an integrated angle command value calculation unit that calculates an integrated angle command value by adding the manual steering command value to an automatic steering command value given in a driving assistance mode; a control unit that controls the angle of an electric motor for steering angle control based on the integrated angle command value; and an equation of motion setting unit that changes the equation of motion in accordance with the lateral position of a vehicle reference position with respect to the driving lane and a time derivative of the actual steering angle or a time derivative of the manual steering command value.

[0012] With this configuration, in the driving assistance mode, a steering reaction force can be applied to the driver in a novel manner.

[0013] In one embodiment of the present disclosure, the equation of motion includes a road reaction force characteristic coefficient, and the equation of motion setting unit changes the equation of motion by changing the value of at least one road reaction force characteristic coefficient included in the equation of motion.

[0014] In one embodiment of the present disclosure, the equation of motion setting unit is configured to change the equation of motion by switching between a first equation of motion and a second equation of motion, wherein in the first equation of motion, a target virtual spring reaction force corresponding to the lateral position is used as the virtual spring reaction force, and in the second equation of motion, a virtual spring reaction force that is set using a virtual load spring stiffness coefficient that is constant regardless of the lateral position is used as the virtual spring reaction force.

[0015] In one embodiment of the present disclosure, the equation of motion setting unit is configured to determine whether the steering is being performed due to the driver's inattention or the driver's intention based on the lateral position and the time differential value of the actual steering angle, and to change the equation of motion based on the determination result.

[0016] In one embodiment of the present disclosure, the equation of motion setting unit determines whether the steering is being performed due to the driver's inattention or the driver's intention based on the lateral position and the time derivative value of the actual steering angle, and if the equation of motion setting unit determines that the steering is being performed due to the driver's inattention, it sets the first equation of motion as the equation of motion, and if it determines that the steering is being performed due to the driver's intention, it sets the second equation of motion as the equation of motion.

[0017] In one embodiment of the present disclosure, the equation of motion setting unit is configured to determine whether the vehicle is heading toward the departure side or the departure avoidance side based on the lateral position and the time differential value of the manual steering command value, and to change the equation of motion based on the determination result.

[0018] In one embodiment of the present disclosure, the equation of motion setting unit determines whether the vehicle is heading toward the departure side or toward the departure avoidance side based on the lateral position and the time differential value of the manual steering command value, and when the vehicle is heading toward the departure side, sets the first equation of motion as the equation of motion, and when the vehicle is heading toward the departure avoidance side, sets the second equation of motion as the equation of motion.

[0019] DETAILED DESCRIPTION OF EMBODIMENTS OF THE PRESENT DISCLOSURE Hereinafter, embodiments of the present disclosure will be described in detail with reference to the accompanying drawings.

[0020] FIG. 1 is a schematic diagram showing a general configuration of an electric power steering system to which a motor control device according to an embodiment of the present disclosure is applied.

[0021] The electric power steering system 1 includes a steering wheel (handle) 2 as a steering member for steering the vehicle, a steering mechanism 4 that steers steered wheels 3 in conjunction with the rotation of the steering wheel 2, and a steering assist mechanism 5 that assists the driver in steering. The steering wheel 2 and the steering mechanism 4 are mechanically connected via a steering shaft 6 and an intermediate shaft 7.

[0022] The steering shaft 6 includes an input shaft 8 connected to the steering wheel 2 and an output shaft 9 connected to the intermediate shaft 7. The input shaft 8 and the output shaft 9 are connected via a torsion bar 10 so as to be capable of relative rotation.

[0023] A torque sensor 12 is disposed near the torsion bar 10. The torque sensor 12 detects the torsion bar torque (steering torque) T applied to the steering wheel 2 based on the amount of relative rotational displacement between the input shaft 8 and the output shaft 9. ｔｂ In this embodiment, the torsion bar torque T ｔｂ For example, the torque for steering left is detected as a positive value, and the torque for steering right is detected as a negative value. The larger the absolute value of the torque, the greater the torsion bar torque T ｔｂ The magnitude of is assumed to be large.

[0024] The steering mechanism 4 is made up of a rack-and-pinion mechanism including a pinion shaft 13 and a rack shaft 14 as a steering shaft. The steered wheels 3 are connected to each end of the rack shaft 14 via tie rods 15 and knuckle arms (not shown). The pinion shaft 13 is connected to the intermediate shaft 7. The pinion shaft 13 rotates in conjunction with the steering of the steering wheel 2. A pinion 16 is connected to the tip of the pinion shaft 13.

[0025] The rack shaft 14 extends linearly in the left-right direction of the vehicle. A rack 17 that meshes with the pinion 16 is formed in the axial middle of the rack shaft 14. The pinion 16 and the rack 17 convert the rotation of the pinion shaft 13 into axial movement of the rack shaft 14. By moving the rack shaft 14 in the axial direction, the steered wheels 3 can be steered.

[0026] When the steering wheel 2 is steered (rotated), this rotation is transmitted to the pinion shaft 13 via the steering shaft 6 and the intermediate shaft 7. The rotation of the pinion shaft 13 is then converted into axial movement of the rack shaft 14 by the pinion 16 and the rack 17. As a result, the steered wheels 3 are steered.

[0027] The steering assist mechanism 5 includes an electric motor 18 for generating a steering assist force (assist torque), and a reducer 19 for amplifying the output torque of the electric motor 18 and transmitting it to the steering mechanism 4. The reducer 19 is made up of a worm gear mechanism including a worm gear 20 and a worm wheel 21 that meshes with the worm gear 20. The reducer 19 is housed in a gear housing 22 that serves as a transmission mechanism housing.

[0028] In the following description, the reduction ratio (gear ratio) of the reducer 19 may be represented as N. The reduction ratio N is determined by the worm wheel angle θ, which is the rotation angle of the worm wheel 21. ｗｗ The worm gear angle θ is the rotation angle of the worm gear 20 relative to the ｗｇ The ratio (θ ｗｇ / θ ｗｗ ) is defined as

[0029] The worm gear 20 is rotationally driven by the electric motor 18. The worm wheel 21 is connected to the output shaft 9 so as to be rotatable integrally therewith.

[0030] When the worm gear 20 is rotationally driven by the electric motor 18, the worm wheel 21 is rotationally driven, and motor torque is applied to the steering shaft 6, causing the steering shaft 6 (output shaft 9) to rotate. The rotation of the steering shaft 6 is then transmitted to the pinion shaft 13 via the intermediate shaft 7. The rotation of the pinion shaft 13 is converted into axial movement of the rack shaft 14, thereby turning the steered wheels 3. In other words, by rotating the worm gear 20 with the electric motor 18, steering assistance by the electric motor 18 and steering of the steered wheels 3 become possible. The electric motor 18 is provided with a rotation angle sensor 23 for detecting the rotation angle of the rotor of the electric motor 18.

[0031] The torque applied to the output shaft 9 (an example of a drive target of the electric motor 18) includes a motor torque by the electric motor 18 and a disturbance torque T ｌｃ Disturbance torque other than the motor torque T ｌｃ Torsion bar torque T ｔｂ, road reaction torque (road load torque) T ｒｌ , friction torque T ｆ etc. are included.

[0032] Torsion bar torque T ｔｂ is the torque applied to the output shaft 9 from the steering wheel 2 side by the force applied to the steering wheel 2 by the driver, the force generated by steering inertia, etc.

[0033] Road reaction torque T ｒｌ is the torque applied to the output shaft 9 from the steered wheels 3 side via the rack shaft 14 due to the self-aligning torque generated in the tire, the force generated by the suspension and tire / wheel alignment, the frictional force of the rack and pinion mechanism, etc.

[0034] The vehicle is equipped with a CCD (Charge Coupled Device) camera 25 that photographs the road ahead in the direction of travel of the vehicle, a GPS (Global Positioning System) 26 for detecting the vehicle's position, a radar 27 for detecting road shapes and obstacles, a map information memory 28 that stores map information, and a vehicle speed sensor 29.

[0035] The CCD camera 25, GPS 26, radar 27, map information memory 28, and vehicle speed sensor 29 are connected to a host ECU (Electronic Control Unit) 201 for performing driving assistance control. Based on the information obtained by the CCD camera 25, GPS 26, radar 27, and vehicle speed sensor 29 and map information, the host ECU 201 performs surrounding environment recognition, vehicle position estimation, route planning, etc., and determines control target values ​​for steering and drive actuators.

[0036] In this embodiment, there are two driving modes: a normal mode and a driving assistance mode. In the driving assistance mode, the host ECU 201 controls the automatic steering command value θ ＡＤ，ｃｍｄ Set the automatic steering command value θ ＡＤ，ｃｍｄ is the target value of the steering angle for driving the vehicle along the target driving line.

[0037] In this embodiment, the driving assistance is a lane keeping assist (LKA) for preventing the vehicle from deviating from its lane. The driving assistance may be a lane centering assist (LCA) for assisting the driver in steering the vehicle so that it stays in the center of the lane. The driving assistance may include both the lane keeping assist (LKA) and the lane centering assist (LCA), as in a modified example of the motor control ECU described below.

[0038] In this embodiment, the automatic steering command value θ ＡＤ，ｃｍｄ is expressed as the amount of rotation (rotation angle) of the output shaft 9 from the neutral position, and the amount of rotation from the neutral position in the left steering direction is expressed as a positive value, and the amount of rotation from the neutral position in the right steering direction is expressed as a negative value. ＡＤ，ｃｍｄ is set based on, for example, the vehicle speed, the lateral deviation from the target driving line (the center line of the lane), and the yaw deviation of the vehicle from the target driving line. ＡＤ，ｃｍｄ The process of setting the value is well known, so a detailed description will be omitted here.

[0039] The host ECU 201 also outputs a mode signal S indicating whether the driving mode is the normal mode or the driving assistance mode. ｍｏｄｅ and lateral deviation e relative to the target driving line Ｌ In this embodiment, the lateral deviation e Ｌ is the distance from the target driving line to the reference position of the vehicle (hereinafter referred to as the "vehicle reference position"). The vehicle reference position is set at a predetermined position in the center of the vehicle width.

[0040] In this embodiment, the lateral deviation e Ｌ is 0 (e Ｌ = 0), and when the vehicle reference position is on the left side of the target driving line in the direction of travel, it becomes a positive value (e Ｌ >0), and when the vehicle reference position is on the right side of the target driving line in the direction of travel, it becomes a negative value (e Ｌ <0). Lateral deviation e Ｌ is an example of the "lateral position of the vehicle reference position with respect to the driving lane" in the present disclosure.

[0041] Mode signal S ｍｏｄｅ , automatic steering command value θ ＡＤ，ｃｍｄ and lateral deviation e Ｌ is given to the motor control ECU 202 via the in-vehicle network. ｔｂ The output signal of the rotation angle sensor 23 is input to the motor control ECU 202. The motor control ECU 202 controls the electric motor 18 based on these input signals and information provided by the host ECU 201.

[0042] FIG. 2 is a block diagram showing the electrical configuration of the motor control ECU 202.

[0043] The following mainly describes the operation when the driving mode is the driving assistance mode.

[0044] The motor control ECU 202 includes a microcomputer 40, a drive circuit (inverter circuit) 31 controlled by the microcomputer 40 to supply power to the electric motor 18, and a current (hereinafter, "motor current I") flowing through the electric motor 18. ｍ and a current detection circuit 32 for detecting the current.

[0045] The microcomputer 40 includes a CPU and memory (ROM, RAM, non-volatile memory, etc.), and functions as a plurality of functional processing sections by executing predetermined programs. The plurality of functional processing sections include a rotation angle calculation section 41, a reduction ratio division section 42, a motion equation setting section 43, an assist torque command value setting section 44, a manual steering command value generation section 45, an integrated angle command value calculation section 46, an angle control section 47, a first weight multiplication section 48, a second weight multiplication section 49, an addition section 50, a torque control section (current control section) 51, and a weight setting section 52.

[0046] The rotation angle calculation unit 41 calculates the rotor rotation angle θ of the electric motor 18 based on the output signal of the rotation angle sensor 23. ｍ The reduction ratio division unit 42 calculates the rotor rotation angle θ ｍ By dividing by the reduction ratio N, the rotor rotation angle θ ｍ The rotation angle (actual steering angle) θ of the output shaft 9 ｃIn this embodiment, the actual steering angle θ ｃ is expressed as the amount of rotation (rotation angle) of the output shaft 9 from the neutral position, and the amount of rotation from the neutral position in the left steering direction is expressed as a positive value, and the amount of rotation from the neutral position in the right steering direction is expressed as a negative value.

[0047] The motion equation setting unit 43 calculates the lateral deviation e given by the host ECU 201. Ｌ Based on this, the target virtual spring reaction force T ｔｂ，ｄ (e Ｌ ) is set. The motion equation setting unit 43 also sets the virtual load spring stiffness coefficient k ｍｄ and the virtual load viscous damping coefficient c ｍｄ Furthermore, the equation of motion setting unit 43 sets third to sixth weights W3 to W6 used by the manual steering command value generating unit 45. In the driving assistance mode, the equation of motion setting unit 43 performs a coefficient / weight setting process, which will be described later. The equation of motion setting unit 43 is an example of the "equation of motion setting unit" in the present disclosure. Details of the operation of the equation of motion setting unit 43 will be described later.

[0048] The assist torque command value setting unit 44 sets the assist torque command value T ａｓｓｔ The assist torque command value setting unit 44 sets the torsion bar torque T ｔｂ Based on this, the assist torque command value T ａｓｓｔ Set.

[0049] As the assist torque command value setting unit 44, for example, the assist torque command value setting unit (51) shown in FIG. 2 of International Publication No. 2023 / 286169 (Patent Document 2) can be used. In this case, the torsion bar torque T ｔｂ Assist torque command value T ａｓｓｔ As an example of setting the torsion bar torque T, the setting example shown in FIG. 3 of International Publication No. 2023 / 286169 can be used. ｔｂ and the assist torque command value T ａｓｓｔThe assist torque command value setting unit 44 may set the torsion bar torque T ｔｂ is multiplied by a preset constant to obtain the assist torque command value T ａｓｓｔ may be calculated.

[0050] The manual steering command value generating unit 45 basically generates a steering angle (more precisely, a rotation angle θ of the output shaft 9) corresponding to the steering wheel operation when the driver operates the steering wheel 2. ｃ ) is the manual steering command value θ ＭＤ，ｃｍｄ The manual steering command value generating unit 45 is provided to set the torsion bar torque T ｔｂ and the assist torque command value T set by the assist torque command value setting unit 44. ａｓｓｔ and the target virtual spring reaction force T set by the motion equation setting unit 43. ｔｂ，ｄ (e Ｌ ), virtual load spring stiffness coefficient k ｍｄ , virtual load viscous damping coefficient c ｍｄ and weights W3 to W6 are used to calculate the manual steering command value θ ＭＤ，ｃｍｄ The manual steering command value generating unit 45 will be described in detail later.

[0051] The integrated angle command value calculation unit 46 calculates the automatic steering command value θ set by the host ECU 201. ＡＤ，ｃｍｄ , manual steering command value θ ＭＤ，ｃｍｄ The integrated angle command value θ ｉｎｔ，ｃｍｄ Calculate the following.

[0052] The angle control unit 47 calculates an integrated angle command value θ ｉｎｔ，ｃｍｄ Based on this, the integrated angle command value θ ｉｎｔ，ｃｍｄ The integrated motor torque command value T ｍｉｎｔ，ｃｍｄThe angle control unit 47 may have a configuration in which the rotation angle calculation unit (69) and the reduction ratio division unit (70) are deleted from the angle control unit (54) shown in FIG. 5 of International Publication No. 2023 / 286169 (Patent Document 2). The reason for deleting the rotation angle calculation unit (69) and the reduction ratio division unit (70) is that the rotation angle calculation unit (69) and the reduction ratio division unit (70) correspond to the rotation angle calculation unit 41 and the reduction ratio division unit 42 shown in FIG. 2 of the present application, respectively.

[0053] In the angle control unit (54) shown in FIG. 5 of WO 2023 / 286169, in the cooperative steering mode (corresponding to the driving assistance mode of the present application), the steering angle estimated value ^θ (the steering angle estimated value ^θ ｃ ) corresponds to the integrated angle command value θ ｓｉｎｔ (The integrated angle command value θ ｉｎｔ，ｃｍｄ The electric motor 18 is controlled so as to follow the rotational speed of the motor 18.

[0054] In this embodiment, the angle control unit 47 has a configuration in which the rotation angle calculation unit (69) and the reduction ratio division unit (70) are removed from the angle control unit (54) shown in FIG. 5 of International Publication No. 2023 / 286169 (Patent Document 2). Therefore, in the driving assistance mode, the steering angle estimated value ^θ ｃ is the integrated angle command value θ ｉｎｔ，ｃｍｄ The electric motor 18 is controlled to follow the above.

[0055] The first weight multiplier 48 multiplies the assist torque command value T ａｓｓｔ The second weight multiplier 49 multiplies the integrated motor torque command value T ｍｉｎｔ，ｃｍｄ is multiplied by a second weight W2. The first weight W1 and the second weight W2 are set by the weight setting unit 52.

[0056] The adder 50 calculates the assist torque command value W1·T after the first weight multiplication (after the first weighting process). ａｓｓｔ and the integrated motor torque command value W2·T after multiplication by the second weight (after the second weighting process) ｍｉｎｔ，ｃｍｄ By adding these, the motor torque command value T ｍ，ｃｍｄ Calculate the following.

[0057] When the driving mode is the normal mode, the weight setting unit 52 sets the first weight W1 to 1 and the second weight W2 to 0. When the driving mode is the driving assistance mode, the weight setting unit 52 sets the first weight W1 to 0 and the second weight W2 to 1. Therefore, when the driving mode is the normal mode, the assist torque command value T ａｓｓｔ is the motor torque command value T ｍ，ｃｍｄ On the other hand, when the driving mode is the driving assistance mode, the integrated motor torque command value T ｍｉｎｔ，ｃｍｄ is the motor torque command value T ｍ，ｃｍｄ is given to the torque control unit 51 as

[0058] The torque control unit 51 controls the motor torque of the electric motor 18 to be equal to the motor torque command value T ｍ，ｃｍｄ The drive circuit 31 is driven so that the torque control unit 51 approaches the torque command value T ｍ，ｃｍｄ The torque control unit 51 calculates a current command value by dividing the motor current I ｍ Feedback control is performed so that the current command value approaches the reference value.

[0059] Next, the target virtual spring reaction force T ｔｂ，ｄ (e Ｌ ), virtual load spring stiffness coefficient k ｍｄ and the virtual load viscous damping coefficient c ｍｄ This article explains:

[0060] FIG. 3 shows the lateral deviation e Ｌ Target virtual spring reaction force T ｔｂ，ｄ (e Ｌ ) is a graph showing an example of setting.

[0061] Lateral deviation e Ｌ Ga-e Ｌ，ｓ (However, e Ｌ，ｓ >0) to e Ｌ，ｓIn the range up to ｔｂ，ｄ (e Ｌ ) is -T ｔｂ，ｄ，ｓ (However, T ｔｂ，ｄ，ｓ >0) to T ｔｂ，ｄ，ｓ Until, lateral deviation e Ｌ In this example, the target virtual spring reaction force T ｔｂ，ｄ (e Ｌ ) varies linearly, but may vary nonlinearly. In this example, e Ｌ，ｓ is set to a predetermined value that is greater than zero and less than half the width of the driving lane.

[0062] Lateral deviation e Ｌ Gae Ｌ，ｓ From e Ｌ，ｍ (However, e Ｌ，ｍ >e Ｌ，ｓ ) in the range up to the target virtual spring reaction force T ｔｂ，ｄ (e Ｌ ) is T ｔｂ，ｄ，ｓ From T ｔｂ，ｄ，ｍ (However, T ｔｂ，ｄ，ｍ >T ｔｂ，ｄ，ｓ ) and lateral deviation e Ｌ The larger the lateral deviation e is, the larger the Ｌ Gae Ｌ，ｓ From e Ｌ，ｍ In the range up to lateral deviation e Ｌ Ga-e Ｌ，ｓ From e Ｌ，ｓ Compared with the range up to the target virtual spring reaction force T ｔｂ，ｄ (e Ｌ In this example, the slope of the line representing the target virtual spring reaction force T ｔｂ，ｄ (e Ｌ ) changes linearly, but may change nonlinearly. Ｌ Gae Ｌ，ｍ In the larger range, the target virtual spring reaction force T ｔｂ，ｄ (e Ｌ ) is T ｔｂ，ｄ，ｍ is set to.

[0063] Lateral deviation e Ｌ Ga-e Ｌ，ｓ From -e Ｌ，ｍ (However, -e Ｌ，ｍ <-eＬ，ｓ ) in the range up to the target virtual spring reaction force T ｔｂ，ｄ (e Ｌ ) is -T ｔｂ，ｄ，ｓ From -T ｔｂ，ｄ，ｍ (However, -T ｔｂ，ｄ，ｍ <-T ｔｂ，ｄ，ｓ ) and lateral deviation e Ｌ The smaller the lateral deviation e, the smaller the Ｌ Ga-e Ｌ，ｓ From -e Ｌ，ｍ In the range up to lateral deviation e Ｌ Ga-e Ｌ，ｓ From e Ｌ，ｓ Compared with the range up to the target virtual spring reaction force T ｔｂ，ｄ (e Ｌ In this example, the slope of the line representing the target virtual spring reaction force T ｔｂ，ｄ (e Ｌ ) changes linearly, but may change nonlinearly. Ｌ Ga-e Ｌ，ｍ In a smaller range, the target virtual spring reaction force T ｔｂ，ｄ (e Ｌ ) is -T ｔｂ，ｄ，ｍ is set to.

[0064] In this embodiment, the virtual load spring stiffness coefficient k ｍｄ Two types of stiffness coefficients are prepared: a first virtual load spring stiffness coefficient kr and a second virtual load spring stiffness coefficient kg.

[0065] FIG. 4 shows the lateral deviation e Ｌ 10 is a graph showing an example of setting a first virtual load spring stiffness coefficient kr and a second virtual load spring stiffness coefficient kg with respect to

[0066] The first virtual load spring stiffness coefficient kr is the lateral deviation e Ｌ Absolute value of |e Ｌ | is e in Fig. 3 Ｌ，ｓ The first virtual load spring stiffness coefficient kr is set only within the following range: Ｌ The second virtual load spring stiffness coefficient kg is set to a constant value k1 regardless of the lateral deviation e. ＬRegardless of the load stiffness coefficients, the coefficient k3 is set to a constant value k3. The coefficient k3 is set to a value greater than 0 and smaller than k1. The value k1 of the first virtual load spring stiffness coefficient kr and the value k3 of the second virtual load spring stiffness coefficient kg shown in FIG. 4 are stored in memory.

[0067] In this embodiment, the virtual load viscous damping coefficient c ｍｄ The first virtual load viscous damping coefficient cr(e Ｌ ) and the second virtual load viscous damping coefficient cg.

[0068] FIG. 5 shows the lateral deviation e Ｌ First virtual load viscous damping coefficient cr(e Ｌ 10 is a graph showing an example of setting the second virtual load viscous damping coefficient cg.

[0069] First virtual load viscous damping coefficient c(e Ｌ ) is the lateral deviation e Ｌ Absolute value of |e Ｌ | Ｌ，ｓ In the following cases, the lateral deviation e is set to a constant value c1. c1 is a predetermined value greater than 0. Ｌ Absolute value of |e Ｌ | Ｌ，ｓ When the first virtual load viscous damping coefficient c(e Ｌ ) is the lateral deviation e from c1 to c2, which is larger than c1. Ｌ Absolute value of |e Ｌ In FIG. 5, the first virtual load viscous damping coefficient c(e Ｌ ) changes linearly from c1 to c2, but may change nonlinearly.

[0070] The second virtual load viscous damping coefficient cg is Ｌ Regardless of the value of c1, the value of c3 is set to a constant value c3. The value of c3 is set to a value greater than 0 and smaller than c1.

[0071] The lateral deviation e shown in FIG. Ｌ First virtual load viscous damping coefficient c(e Ｌ) is stored in the memory as a viscous damping coefficient map. Also, the value c3 of the second virtual load viscous damping coefficient cg shown in FIG. 5 is stored in the memory.

[0072] The manual steering command value generating unit 45 will now be described in detail.

[0073] First, a manual steering command value θ by a manual steering command value generating unit (hereinafter referred to as a "comparative manual steering command value generating unit") described in Patent Document 2 (WO 2023 / 286169) ＭＤ，ｃｍｄ This section explains how to set this up.

[0074] The manual steering command value generating unit of the comparative example uses the reference EPS model of FIG. 6 to calculate the manual steering command value θ ＭＤ，ｃｍｄ The reference EPS model in FIG. 6 is an example of the "reference model of the steering device" of the present disclosure.

[0075] This reference EPS model is a single inertia model including a lower column. The lower column corresponds to the output shaft 9 and the worm wheel 21. However, this model is only an example, and an inertia model including a configuration other than the above (for example, a rack shaft 14) may also be used. In FIG. 6, J ｍｄ is the inertia of the lower column (hereinafter referred to as "column inertia"), and θ ｃｏｌ is the rotation angle of the lower column, and T ｔｂ is the torsion bar torque. ｔｂ , torque N·T acting on the output shaft 9 from the electric motor 18 ｍ and road reaction torque (virtual reaction force) T ｒｌ is given.

[0076] Road reaction torque T ｒｌ is the stiffness coefficient of the virtual spring, the virtual load spring stiffness coefficient k ｍｄ and the virtual load viscous damping coefficient c, which is the viscous damping coefficient of the virtual damper ｍｄ Using the above, it is expressed by the following equation (1).

[0077]

[0078] Virtual load spring stiffness coefficient k ｍｄand the virtual load viscous damping coefficient c ｍｄ has been obtained in advance through experiments, analysis, etc. In the following, k ｍｄ ・θ ｃｏｌ is called the virtual spring reaction force, and c ｍｄ (dθ ｃｏｌ / dt) is sometimes called a virtual damper reaction force.

[0079] The equation of motion of the reference EPS model is expressed by the following equation (2).

[0080]

[0081] In formula (2), J ｍｄ ・d ２ θ ｃｏｌ / dt ２ is the inertia torque acting on the lower column.

[0082] The manual steering command value generating unit of the comparative example is T ｔｂ The torsion bar torque T detected by the torque sensor 12 ｔｂ Substituting, T ｍ The assist torque command value T ａｓｓｔ By substituting the above and solving the differential equation (2), the rotation angle θ of the lower column is obtained. ｃｏｌ Then, the manual steering command value generating unit of the comparative example calculates the obtained rotation angle θ of the lower column. ｃｏｌ The manual steering command value θ ＭＤ，ｃｍｄ In this way, the manual steering command value θ ＭＤ，ｃｍｄ The method of setting is called the comparison method.

[0083] The equation of motion in equation (2) is T ｍ T ａｓｓｔ and θ ｃｏｌ θ ＭＤ，ｃｍｄ is equivalent to the equation of motion in which

[0084] In this embodiment, the manual steering command value generating unit 45 calculates the manual steering command value θ using the equation of motion (Equation (2)) of the reference EPS model described above. ＭＤ，ｃｍｄSpecifically, in this embodiment, the manual steering command value generating unit 45 calculates the manual steering command value θ using a motion equation obtained by modifying the motion equation (Equation (2)) of the reference EPS model described above. ＭＤ，ｃｍｄ Calculate the following.

[0085] FIG. 7 is a block diagram showing the configuration of the manual steering command value generating unit 45.

[0086] In FIG. ｍｄ is the column inertia. s is the differential operator and 1 / s corresponds to the integrator. θ ＭＤ，ｃｍｄ is the manual steering command value, and the rotation angle θ of the lower column in the comparison method ｃｏｌ Equivalent to k ｍｄ is the virtual load spring stiffness coefficient, which is set by the motion equation setting unit 43. ｍｄ is the virtual load viscous damping coefficient, and is set by the motion equation setting unit 43. ａｓｓｔ is the assist torque command value set by the assist torque command value setting unit 44.

[0087] The manual steering command value generation unit 45 includes a reduction ratio multiplication unit 431, an addition / subtraction unit 401, an inertia division unit 402, a first integration unit 403, a second integration unit 404, a virtual damper reaction force calculation unit 405, a first virtual spring reaction force calculation unit 406, a third weight multiplication unit 407, a second virtual spring reaction force calculation unit 408, a fifth weight multiplication unit 409, a first addition unit 410, a sixth weight multiplication unit 411, a second addition unit 412, a fourth weight multiplication unit 413, and a third addition unit 414.

[0088] The reduction ratio multiplication unit 431 calculates the assist torque command value T ａｓｓｔ is multiplied by the reduction ratio N of the reducer 19 to obtain the assist torque command value T ａｓｓｔ is the assist torque command value N·T for the output shaft 9. ａｓｓｔ The assist torque command value N·T for the output shaft 9 calculated by the reduction ratio multiplication unit 431 is converted into ａｓｓｔ is given to the adder / subtractor 401 and also to the first adder 410 .

[0089] The addition / subtraction unit 401 receives the torsion bar torque T ｔｂand the assist torque command value N·T for the output shaft 9 calculated by the reduction ratio multiplication unit 431. ａｓｓｔ and the virtual damper reaction force c given by the virtual damper reaction force calculation unit 405. ｍｄ ・dθ ＭＤ，ｃｍｄ / dt and the addition result X of the third adder 414 are given.

[0090] The addition / subtraction unit 401 calculates the torsion bar torque T ｔｂ Assist torque command value N·T for output shaft 9 ａｓｓｔ The virtual damper reaction force θ is calculated from the result of the addition. ｍｄ ・dθ ＭＤ，ｃｍｄ / dt and X. As a result, the adder / subtractor 401 subtracts J on the left side of the above equation (2). ｍｄ ・d ２ θ ｃｏｌ / dt ２ The inertial torque J corresponds to ｍｄ ・d ２ θ ＭＤ，ｃｍｄ / dt ２ (=T ｔｂ +N.T. ａｓｓｔ -c ｍｄ ・dθ ＭＤ，ｃｍｄ / dt-X) is calculated.

[0091] The inertia division unit 402 calculates the inertia torque J calculated by the addition / subtraction unit 401. ｍｄ ・d ２ θ ＭＤ，ｃｍｄ / dt ２ The column inertia J ｍｄ By dividing by , the manual steering command value θ ＭＤ，ｃｍｄ The second derivative d ２ θ ＭＤ，ｃｍｄ / dt ２ Calculate the following.

[0092] The first integration unit 403 calculates the manual steering command value θ ＭＤ，ｃｍｄ The second derivative d ２ θ ＭＤ，ｃｍｄ / dt ２ By integrating the manual steering command value θ ＭＤ，ｃｍｄ The first derivative dθ ＭＤ，ｃｍｄ / dt is calculated.

[0093] The second integration unit 404 calculates the manual steering command value θ ＭＤ，ｃｍｄ The first derivative dθＭＤ，ｃｍｄ By integrating / dt, the manual steering command value θ ＭＤ，ｃｍｄ This manual steering command value θ ＭＤ，ｃｍｄ is output from the manual steering command value generating unit 45.

[0094] The virtual damper reaction force calculation unit 405 calculates the manual steering command value θ calculated by the first integration unit 403. ＭＤ，ｃｍｄ The first derivative dθ ＭＤ，ｃｍｄ / dt is the virtual load viscous damping coefficient c ｍｄ By multiplying by ｍｄ ・dθ ＭＤ，ｃｍｄ / dt is calculated. This virtual damper reaction force c ｍｄ ・dθ ＭＤ，ｃｍｄ / dt is fed back to the addition / subtraction unit 401 .

[0095] The first virtual spring reaction force calculation unit 406 calculates the manual steering command value θ ＭＤ，ｃｍｄ Virtual load spring stiffness coefficient k ｍｄ By multiplying the first virtual spring reaction force k ｍｄ ・θ ＭＤ，ｃｍｄ Calculate the following.

[0096] The third weight multiplier 407 multiplies the first virtual spring reaction force k ｍｄ ・θ ＭＤ，ｃｍｄ is multiplied by a third weight W3.

[0097] The second virtual spring reaction force calculation unit 408 calculates the manual steering command value θ ＭＤ，ｃｍｄ Virtual load spring stiffness coefficient k ｍｄ By multiplying by , the second virtual spring reaction force k ｍｄ ・θ ＭＤ，ｃｍｄ Calculate the following.

[0098] The fifth weight multiplier 409 calculates the second virtual spring reaction force k ｍｄ ・θ ＭＤ，ｃｍｄ is multiplied by a fifth weight W5.

[0099] The first adder 410 calculates the target virtual spring reaction force T ｔｂ，ｄ (e Ｌ ) and the assist torque command value N·T for the output shaft 9 calculated by the reduction ratio multiplication unit 431. ａｓｓｔThe sixth weight multiplier 411 adds the calculation result (T ｔｂ，ｄ (e Ｌ ) + N.T. ａｓｓｔ ) is multiplied by a sixth weight W6.

[0100] The second adder 412 multiplies the result of calculation W5·k by the fifth weight multiplier 409 by ｍｄ ・θ ＭＤ，ｃｍｄ and the calculation result W6·(T ｔｂ，ｄ (e Ｌ ) + N.T. ａｓｓｔ ) and add.

[0101] The fourth weight multiplier 413 multiplies the calculation result {W5·k ｍｄ ・θ ＭＤ，ｃｍｄ +W6・(T ｔｂ，ｄ (e Ｌ ) + N.T. ａｓｓｔ )} is multiplied by a fourth weight W4.

[0102] The third adder 414 multiplies the result of calculation W3·k by the third weight multiplier 407 by ｍｄ ・θ ＭＤ，ｃｍｄ and the calculation result W4·{W5·k ｍｄ ・θ ＭＤ，ｃｍｄ +W6・(T ｔｂ，ｄ (e Ｌ ) + N.T. ａｓｓｔ The addition result of the third adder 414 [{W3·k ｍｄ ・θ ＭＤ，ｃｍｄ}+W4・{W5・k ｍｄ ・θ ＭＤ，ｃｍｄ +W6・(T ｔｂ，ｄ (e Ｌ ) + N.T. ａｓｓｔ )}] is fed back to the addition / subtraction unit 401 as X.

[0103] In this embodiment, as will be described later, when it is determined that the steering is being performed by the driver's intention (will), the third weight W3 is set to 1 and the fourth weight W4 is set to 0. On the other hand, when it is determined that the steering is being performed by the driver's inattention, the third weight W3 is set to 0 and the fourth weight W4 is set to 1.

[0104] In addition, when it is determined that the steering is being performed due to the driver's carelessness, the lateral deviation e Ｌ Ga-e Ｌ，ｓ is greater than e Ｌ，ｓ If the difference is smaller than 0, the driving assistance mode is the lane centering assist mode (LCA mode), the fifth weight W5 is set to 1, and the sixth weight W6 is set to zero.

[0105] On the other hand, when it is determined that the steering is being performed due to the driver's carelessness, the lateral deviation e Ｌ Ga-e Ｌ，ｓ Below or e Ｌ，ｓ If this is the case, the driving assistance mode becomes the lane keeping assist mode (LKA mode), the fifth weight W5 is set to zero, and the sixth weight W6 is set to one.

[0106] When it is determined that the steering is being performed intentionally by the driver, the addition result X of the third adder 414 is k ｍｄ ・θ ＭＤ，ｃｍｄ Therefore, the calculation result of the addition / subtraction unit 401 is (T ｔｂ +N.T. ａｓｓｔ -c ｍｄ ・dθ ＭＤ，ｃｍｄ / dt-k ｍｄ ・θ ＭＤ，ｃｍｄ ) As will be described later, in this case, ｍｄ = cg (see Figure 5), k ｍｄ = kg (see FIG. 4), the calculation result of the addition / subtraction unit 401 is (T ｔｂ +N.T. ａｓｓｔ -cg・dθ ＭＤ，ｃｍｄ / dt-kg・θ ＭＤ，ｃｍｄ )

[0107] In this case, the manual steering command value generating unit 45A calculates the manual steering command value θ based on the equation of motion of the following equation (3). ＭＤ，ｃｍｄ Calculate the following.

[0108]

[0109] In formula (3), J ｍｄ ・d ２ θ ＭＤ，ｃｍｄ / dt ２is the inertia torque. cg・dθ ＭＤ，ｃｍｄ / dt is the virtual damper reaction force. kg・θ ＭＤ，ｃｍｄ is the virtual spring reaction force.

[0110] That is, when it is determined that the steering is being performed intentionally by the driver, the manual steering command value generating unit 45A calculates the virtual damper reaction force c ｍｄ ・dθ ｃｏｌ / dt as cg dθ ＭＤ，ｃｍｄ / dt, and the virtual spring reaction force k in the equation of motion of the above formula (2) ｍｄ ・θ ｃｏｌ kg・θ ＭＤ，ｃｍｄ Using this, the manual steering command value θ ＭＤ，ｃｍｄ Calculate the following.

[0111] It is determined that the driver is steering due to carelessness, and the lateral deviation e Ｌ Ga-e Ｌ，ｓ is greater than e Ｌ，ｓ If the sum X of the third adder 414 is smaller than k ｍｄ ・θ ＭＤ，ｃｍｄ Therefore, the calculation result of the addition / subtraction unit 401 is (T ｔｂ +N.T. ａｓｓｔ -c ｍｄ ・dθ ＭＤ，ｃｍｄ / dt-k ｍｄ ・θ ＭＤ，ｃｍｄ ) As will be described later, in this case, ｍｄ = cr(e Ｌ ) (see Figure 5), k ｍｄ =kr (see FIG. 4), the calculation result of the addition / subtraction unit 401 is (T ｔｂ +N.T. ａｓｓｔ -cr(e Ｌ ) dθ ＭＤ，ｃｍｄ / dt-kr・θ ＭＤ，ｃｍｄ )

[0112] In this case, the manual steering command value generating unit 45 calculates the manual steering command value θ based on the equation of motion of the following equation (4). ＭＤ，ｃｍｄ Calculate the following.

[0113]

[0114] In formula (4), J ｍｄ ・d ２ θ ＭＤ，ｃｍｄ / dt ２ is the inertia torque. Ｌ ) dθ ＭＤ，ｃｍｄ / dt is the virtual damper reaction force. kr・θ ＭＤ，ｃｍｄ is the virtual spring reaction force.

[0115] That is, in the LCA mode, the manual steering command value generating unit 45 calculates the virtual damper reaction force c ｍｄ ・dθ ｃｏｌ / dt as lateral deviation e Ｌ cr(e Ｌ ) dθ ＭＤ，ｃｍｄ / dt, and the virtual spring reaction force k in the equation of motion of the above formula (2) ｍｄ ・θ ｃｏｌ As kr・θ ＭＤ，ｃｍｄ Using this, the manual steering command value θ ＭＤ，ｃｍｄ Therefore, in the LCA mode, the virtual damper reaction force and the virtual spring reaction force can be made larger than when it is determined that the steering is being performed intentionally by the driver.

[0116] It is determined that the driver is steering due to carelessness, and the lateral deviation e Ｌ Ga-e Ｌ，ｓ Below or e Ｌ，ｓ If it is equal to or greater than this, the addition result X of the third adder 414 is (T ｔｂ，ｄ (e Ｌ ) + N.T. ａｓｓｔ ) Therefore, the calculation result of the addition / subtraction unit 401 is (T ｔｂ -c ｍｄ ・dθ ＭＤ，ｃｍｄ / dt-T ｔｂ，ｄ (e Ｌ )) As will be described later, in this case, ｍｄ = cr(e Ｌ ) (see FIG. 5), the calculation result of the adder / subtractor 401 is set to (T ｔｂ -cr(e Ｌ ) dθ ＭＤ，ｃｍｄ / dt-T ｔｂ，ｄ (e Ｌ )) becomes.

[0117] In this case, the manual steering command value generating unit 45 calculates the manual steering command value θ based on the equation of motion of the following equation (5). ＭＤ，ｃｍｄ Calculate the following.

[0118]

[0119] In formula (5), J ｍｄ ・d ２ θ ＭＤ，ｃｍｄ / dt ２ is the inertia torque. Ｌ ) dθ ＭＤ，ｃｍｄ / dt is the virtual damper reaction force. ｔｂ，ｄ (e Ｌ ) is the target virtual spring reaction force.

[0120] That is, in the LKA mode, the manual steering command value generating unit 45 calculates the N·T in the equation of motion of the above-mentioned formula (2). ｍ (=N.T. ａｓｓｔ ) is set to 0, and the virtual damper reaction force c ｍｄ ・dθ ｃｏｌ / dt as lateral deviation e Ｌ The virtual damper reaction force cr (e Ｌ ) dθ ＭＤ，ｃｍｄ / dt, and the virtual spring reaction force k in the equation of motion of the above formula (2) ｍｄ ・θ ｃｏｌ As a result, the lateral deviation e Ｌ Target virtual spring reaction force T according to ｔｂ，ｄ (e Ｌ ) to obtain the manual steering command value θ ＭＤ，ｃｍｄ Perform calculations.

[0121] Therefore, in the LKA mode, the virtual damper reaction force can be made larger than when it is determined that the steering is being performed intentionally by the driver. Also, in the LKA mode, the lateral deviation e Ｌ This allows the driver to easily recognize the distance from the center of the lane or the distance to the lane.

[0122] In FIG. 7, the first adder 410 adds the calculation result N·T of the reduction ratio multiplier 431. ａｓｓｔis given to the first adder 410, but the calculation result N·T of the reduction ratio multiplier 431 is given to the first adder 410. ａｓｓｔ In this case, in the LKA mode, the manual steering command value generating unit 45 adds N·T to the right side of the above equation (5). ａｓｓｔ Based on the equation of motion to which is added, the manual steering command value ＭＤ，ｃｍｄ The following calculation is performed.

[0123] 8A and 8B are flowcharts showing the steps of the coefficient / weight setting process performed by the equation of motion setting unit 43 in the driving assistance mode. The coefficient / weight setting process shown in Fig. 8A and 8B is started every time the driving assistance mode is started, and is repeatedly executed at predetermined calculation intervals until the driving assistance mode is canceled.

[0124] The equation of motion setting unit 43 first calculates the lateral deviation e given by the host ECU 201. Ｌ and the actual steering angle θ calculated by the reduction ratio division unit 42 (see FIG. 2). ｃ is acquired (step S1).

[0125] Next, the motion equation setting unit 43 calculates the lateral deviation e Ｌ In other words, the motion equation setting unit 43 determines whether the lateral deviation e Ｌ Determine whether the sign of is negative.

[0126] Lateral deviation e Ｌ is smaller than 0 (step S2: YES), the motion equation setting unit 43 calculates the actual steering angle θ ｃ The time derivative dθ ｃ It is determined whether / dt is equal to or less than a predetermined threshold value -β (where β>0) (step S3).

[0127] Time differential value dθ ｃ If it is determined that / dt is equal to or less than -β (step S3: YES), the equation of motion setting unit 43 determines that the steering is being performed intentionally by the driver, and proceeds to step S4.

[0128] That is, when the vehicle reference position is to the right of the center of the lane, the time differential value dθ ｃIf / dt is less than -β (where β>0), that is, if the steering wheel is steered in the right steering direction at an angular velocity of β or more, the equation of motion setting unit 43 determines that the steering is being performed intentionally by the driver.

[0129] In step S4, the motion equation setting unit 43 sets the third weight W3 to 1, the fourth weight W4 to 0, and sets the second virtual load spring stiffness coefficient kg to the virtual load spring stiffness coefficient k ｍｄ and the second virtual load viscous damping coefficient cg is set as the virtual load viscous damping coefficient c ｍｄ As a result, the manual steering command value generating unit 45 calculates the manual steering command value θ based on the above equation (3). ＭＤ，ｃｍｄ After the process of step S4 is performed, the equation of motion setting unit 43 ends the process for the current calculation cycle.

[0130] In step S3, the time differential value dθ ｃ If it is determined that / dt is greater than -β (step S3: NO), the equation of motion setting unit 43 determines that the steering is being performed due to the driver's carelessness, and proceeds to step S5.

[0131] That is, when the vehicle reference position is to the right of the center of the lane, the time differential value dθ ｃ If / dt is greater than -β (where β>0), the equation of motion setting unit 43 determines that the steering is being performed due to carelessness on the part of the driver.

[0132] In step S5, the equation of motion setting unit 43 sets the third weight W3 to 0 and the fourth weight W4 to 1. Furthermore, the equation of motion setting unit 43 sets the first virtual load viscous damping coefficient cr(e Ｌ ) is the virtual load viscous damping coefficient c ｍｄ Specifically, the equation of motion setting unit 43 sets the lateral deviation e Ｌ First virtual load viscous damping coefficient cr(e Ｌ ) and the lateral deviation e obtained in step S1. Ｌ Based on this, the lateral deviation e Ｌ The first virtual load viscous damping coefficient cr(e Ｌ) is used as the virtual load viscous damping coefficient c ｍｄ Set as.

[0133] Then, the motion equation setting unit 43 calculates the lateral deviation e Ｌ Ga-e Ｌ，ｓ is greater than e Ｌ，ｓ It is determined whether or not the LCA mode condition that the LCA mode condition is smaller than (step S6).

[0134] If the LCA mode conditions are satisfied (step S6: YES), the motion equation setting unit 43 sets the fifth weight W5 to 1, the sixth weight W6 to 0, and sets the first virtual load spring stiffness coefficient kr to the virtual load spring stiffness coefficient k ｍｄ (Step S7). As a result, the manual steering command value generating unit 45 sets the manual steering command value θ ＭＤ，ｃｍｄ After the process of step S7 is performed, the equation of motion setting unit 43 ends the process for the current calculation cycle.

[0135] In step S6, when it is determined that the LCA mode condition is not satisfied (step S6: NO), the motion equation setting unit 43 sets the fifth weight W5 to 0 and the sixth weight W6 to 1 (step S8). As a result, the manual steering command value generating unit 45 calculates the manual steering command value θ based on the equation (5). ＭＤ，ｃｍｄ After the process of step S8 is performed, the equation of motion setting unit 43 ends the process for the current calculation cycle.

[0136] In step S2, the lateral deviation e Ｌ is determined to be equal to or greater than 0 (step S2: NO), the motion equation setting unit 43 calculates the time differential value dθ ｃ It is determined whether / dt is equal to or greater than β (step S9).

[0137] Time differential value dθ ｃ If it is determined that / dt is equal to or greater than β (step S9: YES), the equation of motion setting unit 43 determines that the steering is being performed intentionally by the driver, and proceeds to step S10.

[0138] That is, when the vehicle reference position is to the left of the center of the lane, the time differential value dθｃ If / dt is greater than or equal to β, that is, if the driver turns the steering wheel in the left steering direction at an angular velocity greater than or equal to β, the equation of motion setting unit 43 determines that the steering is being performed intentionally by the driver.

[0139] In step S10, the motion equation setting unit 43 sets the third weight W3 to 1, the fourth weight W4 to 0, and sets the second virtual load spring stiffness coefficient kg to the virtual load spring stiffness coefficient k ｍｄ and the second virtual load viscous damping coefficient cg is set as the virtual load viscous damping coefficient c ｍｄ As a result, the manual steering command value generating unit 45 calculates the manual steering command value θ based on the above equation (3). ＭＤ，ｃｍｄ After the process of step S10 is performed, the equation of motion setting unit 43 ends the process for the current calculation cycle.

[0140] In step S9, the time differential value dθ ｃ If it is determined that / dt is smaller than β (step S9: NO), the equation of motion setting unit 43 determines that the steering is being performed due to the driver's carelessness, and proceeds to step S11.

[0141] That is, when the vehicle reference position is to the left of the center of the lane, the time differential value dθ ｃ If / dt is smaller than β, the equation of motion setting unit 43 determines that the steering is being performed due to carelessness of the driver.

[0142] In step S11, the equation of motion setting unit 43 sets the third weight W3 to 0 and the fourth weight W4 to 1. The equation of motion setting unit 43A further sets the first virtual load viscous damping coefficient cr(e Ｌ ) is the virtual load viscous damping coefficient c ｍｄ Set as.

[0143] Then, the motion equation setting unit 43 calculates the lateral deviation e Ｌ Ga-e Ｌ，ｓ is greater than e Ｌ，ｓ It is determined whether or not the LCA mode condition that the LCA mode condition is smaller than (step S12).

[0144] If the LCA mode conditions are satisfied (step S12: YES), the motion equation setting unit 43 sets the fifth weight W5 to 1, the sixth weight W6 to 0, and sets the first virtual load spring stiffness coefficient kr to the virtual load spring stiffness coefficient k ｍｄ (Step S13). As a result, the manual steering command value generating unit 45 sets the manual steering command value θ ＭＤ，ｃｍｄ After the process of step S13 is performed, the equation of motion setting unit 43 ends the process for the current calculation cycle.

[0145] In step S12, when it is determined that the LCA mode condition is not satisfied (step S12: NO), the equation of motion setting unit 43 sets the fifth weight W5 to 0 and the sixth weight W6 to 1 (step S14). As a result, the manual steering command value generating unit 45 calculates the manual steering command value θ based on the equation (5). ＭＤ，ｃｍｄ After the process of step S14 is performed, the equation of motion setting unit 43 ends the process for the current calculation cycle.

[0146] In this embodiment, when the driving mode is the normal driving mode, the assist torque command value T ａｓｓｔ When the driving mode is the driving assistance mode, the electric motor 18 is controlled based only on the integrated motor torque command value T ｍｉｎｔ，ｃｍｄ That is, the electric motor 18 is controlled based on the assist torque command value T ａｓｓｔ a control mode in which the electric motor 18 is controlled based only on the integrated motor torque command value T ｍｉｎｔ，ｃｍｄ The control mode in which the electric motor 18 is controlled can be switched based on the above.

[0147] Furthermore, in the driving assistance mode, it is possible to set a virtual spring reaction force and a virtual damper reaction force that are appropriate for a state in which the steering is being performed due to the driver's carelessness and a state in which the steering is being performed intentionally by the driver, respectively. This makes it possible to generate a steering reaction force that is appropriate for a state in which the steering is being performed due to the driver's carelessness and a state in which the steering is being performed intentionally by the driver, respectively. In other words, in this embodiment, a steering reaction force can be applied to the driver in a novel method in the driving assistance mode.

[0148] Specifically, when the driver is steering due to carelessness and the lateral deviation e Ｌ Ga-e Ｌ，ｓ is greater than e Ｌ，ｓ When it is determined that the steering is being performed intentionally by the driver (when in the LCA mode), the virtual damper reaction force and the virtual spring reaction force can be made larger than when it is determined that the steering is being performed intentionally by the driver. Ｌ Ga-e Ｌ，ｓ Below or e Ｌ，ｓ When it is determined that the lateral deviation e is equal to or greater than the predetermined value (in the LKA mode), the virtual damper reaction force can be made larger than when the steering is performed intentionally by the driver. Ｌ This allows the driver to easily recognize the distance from the center of the lane or the distance to the lane.

[0149] When the threshold value β (β>0) is set to a relatively small value, it is more likely to be determined that the steering is being performed intentionally by the driver. On the other hand, when the threshold value β is set to a relatively large value, it is more likely to be determined that the steering is being performed due to the driver's carelessness. Therefore, the lateral deviation e Ｌ For example, the threshold value β may be set smaller as the vehicle reference position moves away from the center of the lane, that is, as the vehicle reference position approaches the boundary of the lane.

[0150] In addition, the actual steering angle θ is used to determine whether the steering is being performed due to the driver's carelessness or the driver's intention. ｃ The time derivative dθ ｃ / dt, the time derivative dθ ｃ / dt and torsion bar torque T ｔｂ The product of dθ ｃ / dt*T ｔｂ may also be used.

[0151] [Explanation of Modification of Coefficient / Weight Setting Process (Part 1)] Virtual load spring stiffness coefficient k ｍｄ When the first virtual load spring stiffness coefficient kr is switched to the second virtual load spring stiffness coefficient kg, the virtual load spring stiffness coefficient k ｍｄ It is preferable to gradually decrease the virtual load spring stiffness coefficient k ｍｄ When the second virtual load spring stiffness coefficient kg is switched to the first virtual load spring stiffness coefficient kr, the virtual load spring stiffness coefficient k is changed from the first virtual load spring stiffness coefficient kr to the second virtual load spring stiffness coefficient k ｍｄ It is preferable to gradually increase

[0152] Virtual load viscous damping coefficient c ｍｄ is the first virtual load viscous damping coefficient cr(e Ｌ ) to the second virtual load viscous damping coefficient cg, the first virtual load viscous damping coefficient cr(e Ｌ ) to the second virtual load viscous damping coefficient cg Virtual load viscous damping coefficient c ｍｄ It is preferable to gradually decrease the virtual load viscous damping coefficient c ｍｄ is calculated from the second virtual load viscous damping coefficient cg to the first virtual load viscous damping coefficient cr (e Ｌ ) is switched from the second virtual load viscous damping coefficient cg to the first virtual load viscous damping coefficient cr(e Ｌ ) Virtual load viscous damping coefficient c ｍｄ It is preferable to gradually increase

[0153] When switching the third weight W3 from 1 to 0, it is preferable to gradually decrease the third weight W3 from 1 to 0. Similarly, when switching the third weight W3 from 0 to 1, it is preferable to gradually increase the third weight W3 from 0 to 1. The same applies to the other weights W4 to W6.

[0154] When the driving mode is the normal mode, the first weight W1 is set to 1 and the second weight W2 is set to 0, so that the manual steering command value θ ＭＤ，ｃｍｄ is the motor torque command value T ｍ，ｃｍｄ In other words, the manual steering command value θ ＭＤ，ｃｍｄ However, even in the normal mode, the steering reaction force based on the manual steering command value θ ＭＤ，ｃｍｄ In order to be able to continue the calculation operation of the equation of motion setting unit 43, the virtual load spring stiffness coefficient k ｍｄ , virtual load viscous damping coefficient c ｍｄ and the target virtual spring reaction force T ｔｂ，ｄ (e Ｌ ) may be set.

[0155] In this case, when the operation mode is the normal mode, the motion equation setting unit 43 calculates the virtual load spring stiffness coefficient k ｍｄ A predetermined value k Ｍ and the virtual load viscous damping coefficient c ｍｄ is a preset value c Ｍ and the target virtual spring reaction force T ｔｂ，ｄ (e Ｌ ) is set to a predetermined value T ｔｂ，ｄＭ k Ｍ may be set to k1 in FIG. Ｍ may be set to c1 in FIG. ｔｂ，ｄＭ For example, T in FIG. ｔｂ，ｄ，ｓ may be set to

[0156] The operation of the manual steering command value generating unit 45 may be stopped in the normal mode. In this case, the motion equation setting unit 43 sets the virtual load spring stiffness coefficient k ｍｄ , virtual load viscous damping coefficient c ｍｄ and the target virtual spring reaction force Tｔｂ，ｄ (e Ｌ ) does not need to be set.

[0157] [Description of Modified Example of Coefficient / Weight Setting Process (Part 2)] In step S3, the time differential value dθ ｃ When it is determined that / dt is larger than −β (step S3: NO), the equation of motion setting unit 43 sets the third weight W3 and the fifth weight W5 to 0, the fourth weight W4 and the sixth weight W6 to 1, and sets the first virtual load viscous damping coefficient cr(e Ｌ ) is the virtual load viscous damping coefficient c ｍｄ It may be set as follows.

[0158] Similarly, in step S9, the time differential value dθ ｃ When it is determined that / dt is smaller than β (step S9: NO), the equation of motion setting unit 43 sets the third weight W3 and the fifth weight W5 to 0, the fourth weight W4 and the sixth weight W6 to 1, and sets the first virtual load viscous damping coefficient cr(e Ｌ ) is the virtual load viscous damping coefficient c ｍｄ It may be set as follows.

[0159] That is, when it is determined that the steering is being performed due to the driver's carelessness (NO in step S3A or step S9A), the manual steering command value generating unit 45 calculates the lateral deviation e Ｌ Regardless of this, the manual steering command value θ ＭＤ，ｃｍｄ may be calculated.

[0160] In the above embodiment, the virtual load viscous damping coefficient c ｍｄ The value of the virtual load viscous damping coefficient c is switched between a case where it is determined that the steering is being performed intentionally by the driver and a case where it is determined that the steering is being performed due to the driver's carelessness, but it is not necessary to switch between these cases. ｍｄ The value of may be a fixed value.

[0161] [Explanation of a First Modification of the Motor Control ECU] Instead of the manual steering command value generating unit 45 in FIG. 2, as shown by the broken line in FIG. 2, an automatic steering command value θ ＡＤ．ｃｍｄ Hereinafter, a motor control ECU in which the manual steering command value generation unit 45A is used instead of the manual steering command value generation unit 45 will be referred to as a motor control ECU 202A according to the first modified example.

[0162] 9 is a block diagram showing the configuration of the manual steering command value generating unit 45 A. In FIG. 9, parts corresponding to those in FIG. 7 are denoted by the same reference numerals as in FIG.

[0163] The manual steering command value generation unit 45A includes a reduction ratio multiplication unit 431, an addition / subtraction unit 401, an inertia division unit 402, a first integration unit 403, a second integration unit 404, a first virtual damper reaction force calculation unit 405, a first virtual spring reaction force calculation unit 406, a third weight multiplication unit 407, a second virtual spring reaction force calculation unit 408, a fifth weight multiplication unit 409, a first-order differentiation unit 421, a second virtual damper reaction force calculation unit 422, a second-order differentiation unit 423, an inertia multiplication unit 424, a first addition unit 410, a sixth weight multiplication unit 411, a second addition unit 412, a fourth weight multiplication unit 413, and a third addition unit 414.

[0164] The manual steering command value generation unit 45A in Figure 9 has a first-order differentiation unit 421, a second virtual damper reaction force calculation unit 422, a second-order differentiation unit 423, and an inertia multiplication unit 424 added to the manual steering command value generation unit 45 in Figure 7.

[0165] The first-order differentiation unit 421 calculates the automatic steering command value θ ＡＤ,ｃｍｄ The second virtual damper reaction force calculation unit 422 calculates the automatic steering command value θ ＡＤ,ｃｍｄ The first derivative dθ ＡＤ,ｃｍｄ / dt is the virtual load viscous damping coefficient c ｍｄ By multiplying this, the second virtual damper reaction force c ｍｄ ・dθ ＡＤ,ｃｍｄ / dt is calculated. ｍｄ ・dθ ＡＤ,ｃｍｄ / dt is the automatic steering command value θ ＡＤ,ｃｍｄHereinafter, the virtual damper reaction force c calculated by the first virtual damper reaction force calculation unit 405 will be referred to as ｍｄ ・dθ ＭＤ,ｃｍｄ / dt is referred to as a first virtual damper reaction force.

[0166] The second-order differentiation unit 423 calculates the automatic steering command value θ ＡＤ,ｃｍｄ The inertia multiplication unit 424 calculates the second-order derivative of the automatic steering command value θ ＡＤ,ｃｍｄ The second derivative d ２ θ ＡＤ,ｃｍｄ / dt ２ Column inertia J ｍｄ By multiplying by , the automatic steering command value θ ＡＤ,ｃｍｄ Inertia torque J ｍｄ ・d ２ θ ＡＤ,ｃｍｄ / dt ２ Calculate the following.

[0167] The first adder 410 calculates the automatic steering command value θ ＡＤ,ｃｍｄ Virtual damper reaction force (second virtual damper reaction force) c ｍｄ ・dθ ＡＤ,ｃｍｄ / dt and the automatic steering command value θ ＡＤ,ｃｍｄ Inertia torque J ｍｄ ・d ２ θ ＡＤ,ｃｍｄ / dt ２ and the target virtual spring reaction force T ｔｂ，ｄ (e Ｌ ) and the assist torque command value N·T for the output shaft 9 ａｓｓｔ Add and.

[0168] The sixth weight multiplier 411 multiplies the calculation result (c ｍｄ ・dθ ＡＤ,ｃｍｄ / dt+J ｍｄ ・d ２ θ ＡＤ,ｃｍｄ / dt ２ +T ｔｂ，ｄ (e Ｌ ) + N.T. ａｓｓｔ ) is multiplied by a sixth weight W6.

[0169] The second adder 412 multiplies the result of calculation W5·k by the fifth weight multiplier 409 by ｍｄ ・θ ＭＤ，ｃｍｄ and the calculation result W6·(c ｍｄ ・dθＡＤ,ｃｍｄ / dt+J ｍｄ ・d ２ θ ＡＤ,ｃｍｄ / dt ２ +T ｔｂ，ｄ (e Ｌ ) + N.T. ａｓｓｔ ) and add.

[0170] The fourth weight multiplier 413 multiplies the calculation result {W5·k ｍｄ ・θ ＭＤ，ｃｍｄ +W6 (c ｍｄ ・dθ ＡＤ,ｃｍｄ / dt+J ｍｄ ・d ２ θ ＡＤ,ｃｍｄ / dt ２ +T ｔｂ，ｄ (e Ｌ ) + N.T. ａｓｓｔ )} is multiplied by a fourth weight W4.

[0171] The third adder 414 multiplies the result of calculation W3·k by the third weight multiplier 407 by ｍｄ ・θ ＭＤ，ｃｍｄ and the calculation result W4·{W5·k ｍｄ ・θ ＭＤ，ｃｍｄ +W6 (c ｍｄ ・dθ ＡＤ,ｃｍｄ / dt+J ｍｄ ・d ２ θ ＡＤ,ｃｍｄ / dt ２ +T ｔｂ，ｄ (e Ｌ ) + N.T. ａｓｓｔ The addition result of the third adder 414 [{W3·k ｍｄ ・θ ＭＤ，ｃｍｄ}+W4・{W5・k ｍｄ ・θ ＭＤ，ｃｍｄ +W6 (c ｍｄ ・dθ ＡＤ,ｃｍｄ / dt+J ｍｄ ・d ２ θ ＡＤ,ｃｍｄ / dt ２ +T ｔｂ，ｄ (e Ｌ ) + N.T. ａｓｓｔ )}] is fed back as Y to the addition / subtraction unit 401 .

[0172] In the motor control ECU 202A according to the first modification, the equation of motion setting unit 43 also performs the same coefficient / weight setting process as the coefficient / weight setting process described with reference to FIGS. 8A and 8B in the driving assistance mode.

[0173] It is determined that the driver is steering due to carelessness, and the lateral deviation e Ｌ Ga-e Ｌ，ｓ Below or e Ｌ，ｓ If it is equal to or greater than this, the addition result Y of the third adder 414 is (c ｍｄ ・dθ ＡＤ,ｃｍｄ / dt+J ｍｄ ・d ２ θ ＡＤ,ｃｍｄ / dt ２ +T ｔｂ，ｄ (e Ｌ ) + N.T. ａｓｓｔ ) Therefore, the calculation result of the addition / subtraction unit 401 is (T ｔｂ -c ｍｄ ・dθ ＭＤ，ｃｍｄ / dt-c ｍｄ ・dθ ＡＤ,ｃｍｄ / dt-J ｍｄ ・d ２ θ ＡＤ,ｃｍｄ / dt ２ -T ｔｂ，ｄ (e Ｌ In this case, c ｍｄ = cr(e Ｌ ) (see FIG. 5), the calculation result of the adder / subtractor 401 is set to {(T ｔｂ -(cr(e Ｌ ) dθ ＭＤ，ｃｍｄ / dt+cr(e Ｌ ) dθ ＡＤ,ｃｍｄ / dt)-J ｍｄ ・d ２ θ ＡＤ,ｃｍｄ / dt ２ -T ｔｂ，ｄ (e Ｌ ).

[0174] In this case, the manual steering command value generating unit 45A calculates the manual steering command value θ based on the equation of motion of the following equation (6). ＭＤ，ｃｍ Calculate the following.

[0175]

[0176] In formula (6), (J ｍｄ ・d ２ θ ＭＤ，ｃｍｄ / dt ２ +J ｍｄ ・d ２ θ ＡＤ，ｃｍｄ / dt ２ ) is the inertia torque. (cr(e Ｌ ) dθ ＭＤ，ｃｍｄ / dt+cr(e Ｌ ) dθ ＡＤ，ｃｍｄ / dt) is the virtual damper reaction force. ｔｂ，ｄ (e Ｌ ) is the target virtual spring reaction force.

[0177] That is, in the LKA mode, the manual steering command value generating unit 45A calculates the N·T in the equation of motion of the above-mentioned formula (2). ｍ (=N.T. ａｓｓｔ ) is set to 0, and the inertia torque J ｍｄ ・d ２ θ ｃｏｌ / dt ２ , virtual damper reaction force c ｍｄ ・dθ ｃｏｌ / dt and virtual spring reaction force k ｍｄ ・θ ｃｏｌ As such, (J ｍｄ ・d ２ θ ＭＤ，ｃｍｄ / dt ２ +J ｍｄ ・d ２ θ ＡＤ，ｃｍｄ / dt ２ ), (cr(e Ｌ ) dθ ＭＤ，ｃｍｄ / dt+cr(e Ｌ ) dθ ＡＤ，ｃｍｄ / dt) and T ｔｂ，ｄ (e Ｌ ) to obtain the manual steering command value θ ＭＤ，ｃｍｄ Calculate the following.

[0178] Therefore, in the LKA mode, the virtual damper reaction force can be made larger than when it is determined that the steering is being performed intentionally by the driver. Also, in the LKA mode, the lateral deviation e ＬThis allows the driver to easily recognize the distance from the center of the lane or the distance to the lane.

[0179] In FIG. 9, the first adder 410 adds the calculation result N·T of the reduction ratio multiplier 431. ａｓｓｔ is given to the first adder 410, but the calculation result N·T of the reduction ratio multiplier 431 is given to the first adder 410. ａｓｓｔ In this case, in the LKA mode, the manual steering command value generating unit 45A does not need to add N·T to the right side of the above equation (6). ａｓｓｔ Based on the equation of motion to which is added, the manual steering command value θ ＭＤ，ｃｍｄ The following calculation is performed.

[0180] The motor control ECU 202A according to the first modification has the same advantages as the previously described embodiment. Compared to the previously described embodiment, the motor control ECU 202A according to the first modification has the advantage of being able to reduce the sense of discomfort felt by the driver in the LKA mode. This will be described below.

[0181] As mentioned above, in the driving assistance mode, the steering angle estimate ^θ ｃ is the integrated angle command value θ ｉｎｔ，ｃｍｄ (See FIG. 2 and FIG. 5 of WO 2023 / 286169). ｃ is the actual steering angle θ ｃ Therefore, in the driving assistance mode, the actual steering angle θ ｃ is the integrated angle command value θ ｉｎｔ，ｃｍｄ The electric motor 18 is controlled so as to follow the actual steering angle θ ｃ is the integrated angle command value θ ｉｎｔ，ｃｍｄ Assuming that the system follows the ＭＤ，ｃｍｄ = θ ｃ -θ ＡＤ，ｃｍｄ The following relationship holds.

[0182] In this case, the manual steering command value θ in the above equation (6) ＭＤ，ｃｍｄ Virtual damper reaction force cr (e Ｌ ) dθ ＭＤ，ｃｍｄ / dt is expressed by the following equation (7).

[0183]

[0184] Further, the manual steering command value θ ＭＤ，ｃｍｄ Inertia torque J ｍｄ ・d ２ θ ＭＤ，ｃｍｄ / dt ２ is expressed by the following equation (8).

[0185]

[0186] That is, cr(e Ｌ ) dθ ＭＤ，ｃｍｄ / dt is the actual steering angle θ ｃ The actual steering angle component cr (e Ｌ ) dθ ｃ / dt and the automatic steering command value θ ＡＤ，ｃｍｄ Automatic steering component -cr (e Ｌ ) dθ ＡＤ，ｃｍｄ / dt. Similarly, J ｍｄ ・d ２ θ ＭＤ，ｃｍｄ / dt ２ is the actual steering angle θ ｃ Actual steering angle component J corresponding to the second derivative of ｍｄ ・d ２ θ ｃ / dt ２ and the automatic steering command value θ ＡＤ，ｃｍｄ Automatic steering component according to the second derivative of -J ｍｄ ・d ２ θ ＡＤ，ｃｍｄ / dt ２ Includes:

[0187] These actual steering angle components cr(e Ｌ ) dθ ｃ / dt and J ｍｄ ・d ２ θ ｃ / dt ２ Since the automatic steering component -cr(e Ｌ ) dθ ＡＤ，ｃｍｄ / dt and -J ｍｄ ・d ２ θ ＡＤ，ｃｍｄ / dt ２ Since −dθ is not related to the driver's behavior, the driver may feel uncomfortable. ＡＤ，ｃｍｄThe absolute value of / dt is -d ２ θ ＡＤ，ｃｍｄ / dt ２ Since the absolute value of the virtual damper reaction force is larger than the absolute value of Ｌ ) dθ ＡＤ，ｃｍｄ / dt is likely to have a negative effect on the steering feel.

[0188] In the first modified example of the motor control ECU, the equation of motion of the above-mentioned formula (6) is expressed as a virtual damper reaction force, and the manual steering command value θ ＭＤ，ｃｍｄ Virtual damper reaction force cr (e Ｌ ) dθ ＭＤ，ｃｍｄ / dt plus the automatic steering command value θ ＡＤ，ｃｍｄ Virtual damper reaction force cr (e Ｌ ) dθ ＡＤ，ｃｍｄ The equation of motion of the above formula (6) includes the manual steering command value θ ＭＤ，ｃｍｄ Inertia torque J ｍｄ ・d ２ θ ＭＤ，ｃｍｄ / dt ２ In addition to the automatic steering command value θ ＡＤ，ｃｍｄ Inertia torque J ｍｄ ・d ２ θ ＡＤ，ｃｍｄ / dt ２ Includes.

[0189] As a result, the manual steering command value θ ｍｄ Virtual damper reaction force cr (e Ｌ ) dθ ＭＤ，ｃｍｄ / dt included in the automatic steering component -cr(e Ｌ ) dθ ＡＤ，ｃｍｄ Similarly, the manual steering command value θ ＭＤ，ｃｍｄ Inertia torque J ｍｄ ・d ２ θ ＭＤ，ｃｍｄ / dt ２ Automatic steering component contained in -J ｍｄ ・d ２ θ ＡＤ，ｃｍｄ / dt ２ This can reduce the sense of discomfort felt by the driver in the LKA mode.

[0190] θ ＭＤ，ｃｍｄ = θ ｃ-θ ＡＤ，ｃｍｄ If it is assumed that the above relationship holds, the equation of motion of equation (6) becomes as shown in the following equation (9).

[0191]

[0192] In this case, cr(e Ｌ ) dθ ＭＤ，ｃｍｄ / dt included in the automatic steering component -cr(e Ｌ ) dθ ＡＤ，ｃｍｄ / dt is compensated for, and the actual steering angle θ ｃ Actual steering angle component cr (e Ｌ ) dθ ｃ Only / dt remains. ｍｄ ・d ２ θ ＭＤ，ｃｍｄ / dt ２ Automatic steering component contained in -J ｍｄ ・d ２ θ ＡＤ，ｃｍｄ / dt ２ is compensated, and the actual steering angle θ ｃ J against ｍｄ ・d ２ θ ｃ / dt ２ Only remains.

[0193] The contents explained in the above [Explanation of Modified Example of Coefficient / Weight Setting Process (Part 1)] can also be applied to the motor control ECU 202A according to the first modified example.

[0194] Furthermore, in the motor control ECU 202A according to the first modification, when it is determined in step S3 of FIG. 8A or step S9 of FIG. 8B that the steering is being performed due to the driver's carelessness, the equation of motion setting unit 43 sets the third weight W3 and the fifth weight W5 to 0, the fourth weight W4 and the sixth weight W6 to 1, and sets the first virtual load viscous damping coefficient cr(e Ｌ ) is the virtual load viscous damping coefficient c ｍｄ It may be set as follows.

[0195] That is, when it is determined that the steering is being performed due to the driver's carelessness (NO in step S3 or step S9), the manual steering command value generating unit 45A calculates the lateral deviation e ＬRegardless of this, the manual steering command value θ ＭＤ，ｃｍｄ may be calculated.

[0196] [Explanation of Second Modification of Motor Control ECU] FIG. 10 is a block diagram showing a second modification of the motor control ECU.

[0197] In the motor control ECU 202B according to the second modification, the operation of the equation of motion setting unit 43B is different from that of the motor control ECU 202 shown in FIG.

[0198] The equation of motion setting unit 43B receives the mode signal S ｍｏｄｅ and lateral deviation e Ｌ However, unlike the equation of motion setting unit 43 in the motor control ECU 202 in FIG. 2, the equation of motion setting unit 43B does not input the actual steering angle θ ｃ is not input, and the manual steering command value θ generated by the manual steering command value generating unit 45 is ＭＤ，ｃｍｄ is entered.

[0199] The configuration of the manual steering command value generating unit 45 is the same as the configuration shown in Fig. 7. However, the coefficient / weight setting process performed by the equation of motion setting unit 43B is different from the process performed by the coefficient / weight setting process performed by the equation of motion setting unit 43 in the motor control ECU 202 in Fig. 2.

[0200] The target virtual spring reaction force T set by the motion equation setting unit 43B ｔｂ，ｄ (e Ｌ ), two types of virtual load spring stiffness coefficient k ｍｄ (kr, kg) and two types of virtual load viscous damping coefficients c ｍｄ (cr(e Ｌ ), cg) are the same as those set by the equation of motion setting unit 43 in the motor control ECU 202 in FIG. 2, respectively.

[0201] The motion equation setting unit 43B calculates the lateral deviation e Ｌ and manual steering command value θ ＭＤ，ｃｍｄBased on the above, it is determined whether the vehicle is heading toward the departure side or toward the departure-avoidance side (non-departure side). This determination method will be described below.

[0202] Automatic steering command value θ ＡＤ，ｃｍｄ and actual steering angle θ ｃ Angle deviation Δθ Ａ (=θ ｃ -θ ＡＤ，ｃｍｄ ) time derivative dΔθ Ａ / dt and lateral deviation e Ｌ Based on this, it is possible to determine whether the vehicle is heading toward the departure side or toward the departure-avoidance side. This point will be described with reference to FIGS. 11A to 11C.

[0203] 11A, 11B, and 11C are graphs showing the automatic steering command value θ when the vehicle reference position is to the right of the center of the lane. ＡＤ，ｃｍｄ and actual steering angle θ ｃ Angle deviation Δθ Ａ FIG.

[0204] 11A, 11B, and 11C, the steering angle of the large steering wheel 301 is the actual steering angle θ ｃ The steering angle of the small steering wheel 302 is expressed as an automatic steering command value θ ＡＤ，ｃｍｄ is shown schematically.

[0205] 11A is a schematic diagram showing an example of the position of the vehicle 300 when the vehicle reference position is to the right of the lane center 313. Reference numeral 311 denotes the white line of the left lane boundary, and reference numeral 312 denotes the white line of the right lane boundary. When the vehicle reference position is to the right of the lane center 313, the lateral deviation e Ｌ The sign of is negative.

[0206] FIG. 11B shows the actual steering angle θ ｃ and the automatic steering command value θ ＡＤ，ｃｍｄ The signs of the two are positive, and the actual steering angle θ ｃ is the automatic steering command value θ ＡＤ，ｃｍｄ When the angle deviation Δθ is larger than Ａ FIG.

[0207] Actual steering angle θ ｃand the automatic steering command value θ ＡＤ，ｃｍｄ 11B, for example, when the driver turns the steering wheel to the left (positive direction), the angle deviation Δθ Ａ (=θ ｃ -θ ＡＤ，ｃｍｄ ) becomes larger, and the time derivative value dΔθ Ａ / dt is positive.

[0208] On the other hand, the actual steering angle θ ｃ and the automatic steering command value θ ＡＤ，ｃｍｄ 11B, for example, when the driver turns the steering wheel to the right (negative direction), the angle deviation Δθ Ａ becomes smaller, and the time differential value dΔθ Ａ / dt is negative.

[0209] FIG. 11C shows the actual steering angle θ ｃ The sign of is negative, and the automatic steering command value θ ＡＤ，ｃｍｄ The angle deviation Δθ when the sign of is positive Ａ FIG.

[0210] Actual steering angle θ ｃ and the automatic steering command value θ ＡＤ，ｃｍｄ 11C, for example, when the driver turns the steering wheel to the left (positive direction), the angle deviation Δθ Ａ becomes large (approaching 0), and the time derivative value dΔθ Ａ / dt is positive.

[0211] On the other hand, the actual steering angle θ ｃ and the automatic steering command value θ ＡＤ，ｃｍｄ 11C, for example, when the driver turns the steering wheel to the right (negative direction), the angle deviation Δθ Ａ becomes smaller (moves away from 0), and the time derivative value dΔθ Ａ / dt is negative.

[0212] From the above, the lateral deviation e Ｌ If the sign of is negative, that is, if the vehicle reference position is to the right of the center of the lane, the time differential value dΔθ ＡIf / dt is equal to or greater than a predetermined threshold value γ (where γ>0), it can be determined that the vehicle is heading toward the departure-avoidance side. Ａ / dt is not equal to or greater than γ, that is, the time differential value dΔθ Ａ / dt is greater than -γ and less than γ, and the time derivative value dΔθ Ａ When / dt is equal to or less than -γ, it can be determined that the vehicle is heading toward the departure side.

[0213] Lateral deviation e Ｌ If the sign of is positive, that is, if the vehicle reference position is to the left of the center of the lane, the time differential value dΔθ Ａ If / dt is equal to or less than -γ, it can be determined that the vehicle is heading toward the departure-avoidance side. Ａ / dt is not less than -γ, that is, the time differential value dΔθ Ａ When / dt / dt is greater than -γ and less than γ, and the time derivative value dΔθ Ａ When / dt is equal to or greater than γ, it can be determined that the vehicle is heading toward the departure side.

[0214] As mentioned above, the actual steering angle θ ｃ is the integrated angle command value θ ｉｎｔ，ｃｍｄ Assuming that the system follows the ＭＤ，ｃｍｄ = θ ｃ -θ ＡＤ，ｃｍｄ Therefore, the actual steering angle θ ｃ is the integrated angle command value θ ｉｎｔ，ｃｍｄ Assuming that the system follows the current perfectly, Δθ Ａ = θ ＭＤ，ｃｍｄ This becomes:

[0215] Therefore, in the motor control ECU 202B according to the second modification, the motion equation setting unit 43B calculates the lateral deviation e Ｌ When the sign of is negative, the time differential value dθ of the manual steering command value ＭＤ，ｃｍ If the time differential value dθ / dt is equal to or greater than a predetermined threshold value γ (where γ>0), it is determined that the vehicle is heading toward the departure-avoidance side. ＭＤ，ｃｍIf / dt is not equal to or greater than γ, the equation of motion setting unit 43B determines that the vehicle is heading toward the departure side.

[0216] Lateral deviation e Ｌ is positive, the motion equation setting unit 43B calculates the time differential value dθ of the manual steering command value ＭＤ，ｃｍ If / dt is equal to or less than -γ, it is determined that the vehicle is heading toward the departure-avoidance side. ＭＤ，ｃｍ If / dt is not less than -γ, the equation of motion setting unit 43B determines that the vehicle is heading toward the departure side.

[0217] In the motor control ECU 202 according to the second modified example, as will be described later, when it is determined that the vehicle is heading toward the departure-avoidance side, the third weight W3 is set to 1 and the fourth weight W4 is set to 0. On the other hand, when it is determined that the vehicle is heading toward the departure side, the third weight W3 is set to 0 and the fourth weight W4 is set to 1.

[0218] In addition, when it is determined that the vehicle is heading toward the departure side, the lateral deviation e Ｌ Ga-e Ｌ，ｓ is greater than e Ｌ，ｓ If the difference is smaller than 0, the driving assistance mode is the lane centering assist mode (LCA mode), the fifth weight W5 is set to 1, and the sixth weight W6 is set to zero.

[0219] On the other hand, when it is determined that the vehicle is heading toward the departure side, the lateral deviation e Ｌ Ga-e Ｌ，ｓ Below or e Ｌ，ｓ If this is the case, the driving assistance mode becomes the lane keeping assist mode (LKA mode), the fifth weight W5 is set to zero, and the sixth weight W6 is set to one.

[0220] 12A and 12B are flowcharts showing the procedure of the coefficient / weight setting process performed by the equation of motion setting unit 43B in the driving assistance mode. In Fig. 12A and Fig. 12B, the same steps as those in Fig. 8A and Fig. 8B are denoted by the same step numbers.

[0221] The coefficient / weight setting process shown in FIGS. 12A and 12B is started every time the driving assistance mode is started, and is repeatedly executed at predetermined calculation intervals until the driving assistance mode is cancelled.

[0222] The motion equation setting unit 43B first calculates the lateral deviation e given by the host ECU 201. Ｌ and the manual steering command value θ generated in the previous calculation cycle ＭＤ，ｃｍｄ is acquired (step S1A).

[0223] Next, the motion equation setting unit 43B calculates the lateral deviation e Ｌ In other words, the motion equation setting unit 43A determines whether the lateral deviation e Ｌ Determine whether the sign of is negative.

[0224] Lateral deviation e Ｌ is smaller than 0 (step S32: YES), the motion equation setting unit 43B calculates the manual steering command value θ ＭＤ，ｃｍｄ The time derivative dθ ＭＤ，ｃｍｄ It is determined whether / dt is equal to or greater than a predetermined threshold value γ (where γ>0) (step S3A).

[0225] Time differential value dθ ＭＤ，ｃｍｄ If it is determined that / dt is greater than or equal to γ ​​(step S3A: YES), the equation of motion setting unit 43B determines that the vehicle is heading toward the departure avoidance side (non-departure side), and proceeds to step S4.

[0226] In step S4, the motion equation setting unit 43B sets the third weight W3 to 1, the fourth weight W4 to 0, and sets the second virtual load spring stiffness coefficient kg to the virtual load spring stiffness coefficient k ｍｄ and the second virtual load viscous damping coefficient cg is set as the virtual load viscous damping coefficient c ｍｄ As a result, the manual steering command value generating unit 45 calculates the manual steering command value θ based on the above equation (3). ＭＤ，ｃｍｄ After the process of step S4 is performed, the equation of motion setting unit 43B ends the process for the current calculation cycle.

[0227] In step S3A, the time differential value dθ ＭＤ，ｃｍｄIf it is determined that / dt is smaller than γ (step S3A: NO), the equation of motion setting unit 43B determines that the vehicle is heading toward the departure side, and proceeds to step S5.

[0228] In step S5, the equation of motion setting unit 43B sets the third weight W3 to 0 and the fourth weight W4 to 1. Furthermore, the equation of motion setting unit 43B sets the first virtual load viscous damping coefficient cr(e Ｌ ) is the virtual load viscous damping coefficient c ｍｄ Specifically, the motion equation setting unit 43B sets the lateral deviation e Ｌ First virtual load viscous damping coefficient cr(e Ｌ ) and the lateral deviation e obtained in step S1A. Ｌ Based on this, the lateral deviation e Ｌ The first virtual load viscous damping coefficient cr(e Ｌ ) is used as the virtual load viscous damping coefficient c ｍｄ Set as.

[0229] Then, the motion equation setting unit 43B calculates the lateral deviation e Ｌ Ga-e Ｌ，ｓ is greater than e Ｌ，ｓ It is determined whether or not the LCA mode condition that the LCA mode condition is smaller than (step S6).

[0230] If the LCA mode conditions are satisfied (step S6: YES), the motion equation setting unit 43B sets the fifth weight W5 to 1, the sixth weight W6 to 0, and sets the first virtual load spring stiffness coefficient kr to the virtual load spring stiffness coefficient k ｍｄ (Step S7). As a result, the manual steering command value generating unit 45 sets the manual steering command value θ ＭＤ，ｃｍｄ After the process of step S7 is performed, the equation of motion setting unit 43B ends the process for the current calculation cycle.

[0231] In step S6, when it is determined that the LCA mode condition is not satisfied (step S6: NO), the motion equation setting unit 43B sets the fifth weight W5 to 0 and the sixth weight W6 to 1 (step S8). As a result, the manual steering command value generating unit 45 calculates the manual steering command value θ based on the equation (5). ＭＤ，ｃｍｄ After the process of step S8 is performed, the equation of motion setting unit 43B ends the process for the current calculation cycle.

[0232] In step S2, the lateral deviation e Ｌ is determined to be equal to or greater than 0 (step S2: NO), the motion equation setting unit 43B calculates the time differential value dθ ＭＤ，ｃｍｄ It is determined whether / dt is equal to or less than -γ (step S9A).

[0233] Time differential value dθ ＭＤ，ｃｍｄ If it is determined that / dt is equal to or less than -γ (step S9A: YES), the equation of motion setting unit 43B determines that the vehicle is heading toward the departure-avoidance side, and proceeds to step S10.

[0234] In step S10, the equation of motion setting unit 43B sets the third weight W3 to 1, the fourth weight W4 to 0, and sets the second virtual load spring stiffness coefficient kg to the virtual load spring stiffness coefficient k ｍｄ and the second virtual load viscous damping coefficient cg is set as the virtual load viscous damping coefficient c ｍｄ As a result, the manual steering command value generating unit 45 calculates the manual steering command value θ based on the above equation (3). ＭＤ，ｃｍｄ After the process of step S10 is performed, the equation of motion setting unit 43B ends the process for the current calculation cycle.

[0235] In step S9A, the time differential value dθ ＭＤ，ｃｍｄ If it is determined that / dt is greater than -γ (step S9A: NO), the equation of motion setting unit 43B determines that the vehicle is heading toward the departure side, and proceeds to step S11.

[0236] In step S11, the equation of motion setting unit 43B sets the third weight W3 to 0 and the fourth weight W4 to 1. The equation of motion setting unit 43B further sets the first virtual load viscous damping coefficient cr(e Ｌ ) is the virtual load viscous damping coefficient c ｍｄ Set as.

[0237] Then, the motion equation setting unit 43B calculates the lateral deviation e Ｌ Ga-e Ｌ，ｓ is greater than e Ｌ，ｓ It is determined whether or not the LCA mode condition that the LCA mode condition is smaller than (step S12).

[0238] If the LCA mode conditions are satisfied (step S12: YES), the motion equation setting unit 43B sets the fifth weight W5 to 1, the sixth weight W6 to 0, and sets the first virtual load spring stiffness coefficient kr to the virtual load spring stiffness coefficient k ｍｄ (Step S13). As a result, the manual steering command value generating unit 45 sets the manual steering command value θ ＭＤ，ｃｍｄ After the process of step S13 is performed, the equation of motion setting unit 43B ends the process for the current calculation cycle.

[0239] In step S12, when it is determined that the LCA mode condition is not satisfied (step S12: NO), the motion equation setting unit 43B sets the fifth weight W5 to 0 and the sixth weight W6 to 1 (step S14). As a result, the manual steering command value generating unit 45 calculates the manual steering command value θ based on the equation (5). ＭＤ，ｃｍｄ After the process of step S14 is performed, the equation of motion setting unit 43B ends the process for the current calculation cycle.

[0240] The motor control ECU 202B according to the second modification can set virtual spring reaction forces and virtual damper reaction forces appropriate for the state in which the vehicle is heading toward the departure side and the state in which the vehicle is heading toward the departure avoidance side, respectively. This makes it possible to generate steering reaction forces appropriate for the state in which the vehicle is heading toward the departure side and the state in which the vehicle is heading toward the departure avoidance side, respectively. In other words, the second modification can apply a steering reaction force to the driver in a new method in the driving assistance mode.

[0241] Specifically, when the vehicle is heading toward the departure side and the lateral deviation e Ｌ Ga-e Ｌ，ｓ is greater than e Ｌ，ｓ When it is determined that the lateral deviation e is smaller than the virtual damper reaction force and the virtual spring reaction force, the virtual damper reaction force and the virtual spring reaction force can be made larger than when it is determined that the vehicle is heading toward the departure-avoidance side. Ｌ Ga-e Ｌ，ｓ Below or e Ｌ，ｓ When it is determined that the lateral deviation e is equal to or greater than the predetermined value (when in LKA mode), the virtual damper reaction force can be made larger than when it is determined that the vehicle is heading toward the departure-avoidance side. Ｌ This allows the driver to easily recognize the distance from the center of the lane or the distance to the lane.

[0242] The contents explained in the above [Explanation of Modified Example of Coefficient / Weight Setting Process (Part 1)] can also be applied to the motor controlling ECU 202B according to the second modified example.

[0243] In step S3A, the time differential value dθ ＭＤ，ｃｍｄ When it is determined that / dt is smaller than γ (step S3A: NO), as shown in step S21 indicated by a dashed line in FIG. 12A, the equation of motion setting unit 43B sets the third weight W3 and the fifth weight W5 to 0, the fourth weight W4 and the sixth weight W6 to 1, and sets the first virtual load viscous damping coefficient cr(e Ｌ ) is the virtual load viscous damping coefficient c ｍｄ It may be set as follows.

[0244] Similarly, in step S9A, the time differential value dθ ＭＤ，ｃｍｄ When it is determined that / dt is greater than −γ (step S9A: NO), as shown in step S22 indicated by a dashed line in FIG. 12B, the equation of motion setting unit 43B sets the third weight W3 and the fifth weight W5 to 0, the fourth weight W4 and the sixth weight W6 to 1, and sets the first virtual load viscous damping coefficient cr(e Ｌ ) is the virtual load viscous damping coefficient c ｍｄIt may be set as follows.

[0245] That is, when it is determined that the vehicle is heading toward the departure side (NO in step S3A or step S9A), the manual steering command value generating unit 45 calculates the lateral deviation e Ｌ Regardless of this, the manual steering command value θ ＭＤ，ｃｍｄ may be calculated.

[0246] In the above embodiment, the virtual load viscous damping coefficient c ｍｄ The value of the virtual load viscous damping coefficient c is switched between when it is determined that the vehicle is heading toward the departure-avoidance side and when it is determined that the vehicle is heading toward the departure side, but it does not have to be switched between these two cases. ｍｄ The value of may be a fixed value.

[0247] [Description of Third Modification of Motor Control ECU] The manual steering command value generating unit 45A shown in Fig. 9 may be used instead of the manual steering command value generating unit 45 in Fig. 10. In this case, as shown by the dashed line in Fig. 10, the manual steering command value generating unit 45A receives the automatic steering command value θ ＡＤ．ｃｍｄ is further input. A motor control ECU in which a manual steering command value generating unit 45A is used instead of the manual steering command value generating unit 45 in FIG. 10 will be referred to as a motor control ECU 202C according to a third modified example.

[0248] In the motor control ECU 202C according to the third modified example, the equation of motion setting unit 43B also performs the same coefficient / weight setting process as the coefficient / weight setting process described with reference to FIGS. 12A and 12B.

[0249] The contents explained in the above [Explanation of Modified Example of Coefficient / Weight Setting Process (Part 1)] can also be applied to the motor control ECU 202C according to the third modified example.

[0250] Furthermore, in the motor control ECU 202C according to the third modification, when it is determined in step S3A of FIG. 12A or step S9A of FIG. 12B that the vehicle is heading toward the departure side, the equation of motion setting unit 43B sets the third weight W3 and the fifth weight W5 to 0, the fourth weight W4 and the sixth weight W6 to 1, and sets the first virtual load viscous damping coefficient cr(e Ｌ ) is the virtual load viscous damping coefficient c ｍｄ It may be set as follows.

[0251] That is, when it is determined that the vehicle is heading toward the departure side (NO in step S3A or step S9A), the manual steering command value generating unit 45A calculates the lateral deviation e Ｌ Regardless of this, the manual steering command value θ ＭＤ，ｃｍｄ may be calculated.

[0252] [Description of Fourth Modification of Motor Control ECU] FIG. 13 is a block diagram showing a fourth modification of the motor control ECU.

[0253] In a motor control ECU 202D according to the fourth modification, the operation of the equation of motion setting unit 43D is different from that of the motor control ECU 202 shown in FIG.

[0254] The motion equation setting unit 43D receives the information input to the motion equation setting unit 43 in the motor control ECU 202 in FIG. 2 as well as the manual steering command value θ generated by the manual steering command value generating unit 45. ＭＤ，ｃｍｄ is entered.

[0255] The configuration of the manual steering command value generating unit 45 is the same as the configuration shown in Fig. 7. However, the coefficient / weight setting process performed by the equation of motion setting unit 43D is different from the process performed by the coefficient / weight setting process performed by the equation of motion setting unit 43 in the motor control ECU 202 in Fig. 2.

[0256] The target virtual spring reaction force T set by the motion equation setting unit 43D ｔｂ，ｄ (e Ｌ ), two types of virtual load spring stiffness coefficient k ｍｄ (kr, kg) and two types of virtual load viscous damping coefficients c ｍｄ (cr(eＬ ), cg) are the same as those set by the equation of motion setting unit 43 in the motor control ECU 202 in FIG. 2, respectively.

[0257] In the motor control ECU 202D according to the fourth modification, as will be described later, when it is determined that the vehicle is heading toward the departure-avoidance side, or when it is determined that the vehicle is heading toward the departure side and is being steered intentionally by the driver, the third weight W3 is set to 1 and the fourth weight W4 is set to 0. On the other hand, when it is determined that the vehicle is heading toward the departure side and is being steered due to inattention by the driver, the third weight W3 is set to 0 and the fourth weight W4 is set to 1.

[0258] In addition, when it is determined that the vehicle is heading toward the departure side and that the driver is steering due to carelessness, the lateral deviation e Ｌ Ga-e Ｌ，ｓ is greater than e Ｌ，ｓ If the difference is smaller than 0, the driving assistance mode is the lane centering assist mode (LCA mode), the fifth weight W5 is set to 1, and the sixth weight W6 is set to zero.

[0259] On the other hand, when it is determined that the vehicle is heading toward the departure side and that the driver is steering due to carelessness, the lateral deviation e Ｌ Ga-e Ｌ，ｓ Below or e Ｌ，ｓ If this is the case, the driving assistance mode becomes the lane keeping assist mode (LKA mode), the fifth weight W5 is set to zero, and the sixth weight W6 is set to one.

[0260] 14A and 14B are flowcharts showing the procedure of the coefficient / weight setting process performed by the equation of motion setting unit 43D in the driving assistance mode. In Fig. 14A and Fig. 14B, the same steps as those in Fig. 8A and Fig. 8B or Fig. 12A and Fig. 12B are denoted by the same step numbers.

[0261] The coefficient / weight setting process shown in FIGS. 14A and 14B is started every time the driving assistance mode is started, and is repeatedly executed at predetermined calculation intervals until the driving assistance mode is cancelled.

[0262] The motion equation setting unit 43D first calculates the lateral deviation e given by the host ECU 201. Ｌ and the actual steering angle θ calculated by the reduction ratio division unit 42. ｃ and the manual steering command value θ generated in the previous calculation cycle. ＭＤ，ｃｍｄ and are acquired (step S1B).

[0263] Next, the motion equation setting unit 43D calculates the lateral deviation e Ｌ In other words, the motion equation setting unit 43D determines whether the lateral deviation e Ｌ Determine whether the sign of is negative.

[0264] Lateral deviation e Ｌ is smaller than 0 (step S2: YES), the motion equation setting unit 43D calculates the manual steering command value θ ＭＤ，ｃｍｄ The time derivative dθ ＭＤ，ｃｍｄ It is determined whether / dt is equal to or greater than a threshold value γ (where γ>0) (step S3A).

[0265] Time differential value dθ ＭＤ，ｃｍｄ If it is determined that / dt is equal to or greater than γ (step S3A: YES), the equation of motion setting unit 43D determines that the vehicle is moving toward the departure-avoidance side, and proceeds to step S4.

[0266] In step S4, the motion equation setting unit 43D sets the third weight W3 to 1, the fourth weight W4 to 0, and sets the second virtual load spring stiffness coefficient kg to the virtual load spring stiffness coefficient k ｍｄ and the second virtual load viscous damping coefficient cg is set as the virtual load viscous damping coefficient c ｍｄ As a result, the manual steering command value generating unit 45 calculates the manual steering command value θ based on the above equation (3). ＭＤ，ｃｍｄ After the process of step S4 is performed, the equation of motion setting unit 43D ends the process for the current calculation cycle.

[0267] In step S3A, the time differential value dθＭＤ，ｃｍｄ If it is determined that / dt is smaller than γ (step S3A: NO), the equation of motion setting unit 43D determines that the vehicle is heading toward the departure side, and proceeds to step S3.

[0268] In step S3, the motion equation setting unit 43D calculates the actual steering angle θ ｃ The time derivative dθ ｃ It is determined whether / dt is equal to or less than a threshold value −β (where β>0).

[0269] Time differential value dθ ｃ If it is determined that / dt is equal to or less than -β (step S3: YES), the equation of motion setting unit 43D determines that the vehicle is being steered intentionally by the driver, and proceeds to step S4. In other words, if it is determined that the vehicle is heading toward the departure-avoidance side (step S3A: YES) or if it is determined that the vehicle is heading toward the departure side and is being steered intentionally by the driver (step S3: YES), the process of step S4 is performed.

[0270] In step S3, the time differential value dθ ｃ If it is determined that / dt is greater than -β (step S3: NO), the equation of motion setting unit 43D determines that the steering is being performed due to carelessness of the driver, and proceeds to step S5.

[0271] In other words, if it is determined that the vehicle is heading toward the departure side and that the driver is steering due to carelessness (step S3: NO), the equation of motion setting unit 43D proceeds to step S5.

[0272] In step S5, the equation of motion setting unit 43D sets the third weight W3 to 0 and the fourth weight W4 to 1. Furthermore, the equation of motion setting unit 43D sets the first virtual load viscous damping coefficient cr(e Ｌ ) is the virtual load viscous damping coefficient c ｍｄ Specifically, the motion equation setting unit 43D sets the lateral deviation e Ｌ First virtual load viscous damping coefficient cr(e Ｌ) and the lateral deviation e obtained in step S1B. Ｌ Based on this, the lateral deviation e Ｌ The first virtual load viscous damping coefficient cr(e Ｌ ) is used as the virtual load viscous damping coefficient c ｍｄ Set as.

[0273] Then, the motion equation setting unit 43D calculates the lateral deviation e Ｌ Ga-e Ｌ，ｓ is greater than e Ｌ，ｓ It is determined whether or not the LCA mode condition that the LCA mode condition is smaller than (step S6).

[0274] If the LCA mode conditions are satisfied (step S6: YES), the motion equation setting unit 43D sets the fifth weight W5 to 1, the sixth weight W6 to 0, and sets the first virtual load spring stiffness coefficient kr to the virtual load spring stiffness coefficient k ｍｄ (Step S7). As a result, the manual steering command value generating unit 45 sets the manual steering command value θ ＭＤ，ｃｍｄ After the process of step S7 is performed, the equation of motion setting unit 43D ends the process for the current calculation cycle.

[0275] In step S6, when it is determined that the LCA mode condition is not satisfied (step S6: NO), the motion equation setting unit 43D sets the fifth weight W5 to 0 and the sixth weight W6 to 1 (step S8). As a result, the manual steering command value generating unit 45 calculates the manual steering command value θ based on the equation (5). ＭＤ，ｃｍｄ After the process of step S8 is performed, the equation of motion setting unit 43D ends the process for the current calculation cycle.

[0276] In step S2, the lateral deviation e Ｌ is determined to be equal to or greater than 0 (step S2: NO), the motion equation setting unit 43D calculates the time differential value dθ ＭＤ，ｃｍｄ It is determined whether / dt is equal to or less than -γ (step S9A).

[0277] Time differential value dθ ＭＤ，ｃｍｄIf it is determined that / dt is equal to or less than -γ (step S9A: YES), the equation of motion setting unit 43D determines that the vehicle is heading toward the departure-avoidance side, and proceeds to step S10.

[0278] In step S10, the equation of motion setting unit 43D sets the third weight W3 to 1, the fourth weight W4 to 0, and sets the second virtual load spring stiffness coefficient kg to the virtual load spring stiffness coefficient k ｍｄ and the second virtual load viscous damping coefficient cg is set as the virtual load viscous damping coefficient c ｍｄ As a result, the manual steering command value generating unit 45 calculates the manual steering command value θ based on the above equation (3). ＭＤ，ｃｍｄ After the process of step S10 is performed, the equation of motion setting unit 43D ends the process for the current calculation cycle.

[0279] In step S9A, the time differential value dθ ＭＤ，ｃｍｄ If it is determined that / dt is greater than -β (step S9A: NO), the equation of motion setting unit 43D determines that the vehicle is heading toward the departure side, and proceeds to step S9.

[0280] In step S9, the motion equation setting unit 43D calculates the time differential value dθ ｃ It is determined whether / dt is equal to or greater than β (step S9).

[0281] Time differential value dθ ｃ If it is determined that / dt is equal to or greater than β (step S9: YES), the equation of motion setting unit 43D determines that the vehicle is being steered intentionally by the driver, and proceeds to step S 10. In other words, if it is determined that the vehicle is heading toward the departure-avoidance side (step S9A: YES) or if it is determined that the vehicle is heading toward the departure side and is being steered intentionally by the driver (step S9: YES), the process of step S10 is performed.

[0282] In step S9, the time differential value dθ ｃIf it is determined that / dt is smaller than β (step S9: NO), the equation of motion setting unit 43D determines that the steering is being performed due to carelessness of the driver, and proceeds to step S11.

[0283] That is, when it is determined that the vehicle is heading toward the departure side and that the driver is inattentively steering, the equation of motion setting unit 43D proceeds to step S11.

[0284] In step S11, the equation of motion setting unit 43D sets the third weight W3 to 0 and the fourth weight W4 to 1. The equation of motion setting unit 43D further sets the first virtual load viscous damping coefficient cr(e Ｌ ) is the virtual load viscous damping coefficient c ｍｄ Set as.

[0285] Then, the motion equation setting unit 43D calculates the lateral deviation e Ｌ Ga-e Ｌ，ｓ is greater than e Ｌ，ｓ It is determined whether or not the LCA mode condition that the LCA mode condition is smaller than (step S12).

[0286] If the LCA mode conditions are satisfied (step S12: YES), the motion equation setting unit 43D sets the fifth weight W5 to 1, the sixth weight W6 to 0, and sets the first virtual load spring stiffness coefficient kr to the virtual load spring stiffness coefficient k ｍｄ (Step S13). As a result, the manual steering command value generating unit 45 sets the manual steering command value θ ＭＤ，ｃｍｄ After the process of step S13 is performed, the equation of motion setting unit 43D ends the process for the current calculation cycle.

[0287] In step S12, when it is determined that the LCA mode condition is not satisfied (step S12: NO), the motion equation setting unit 43D sets the fifth weight W5 to 0 and the sixth weight W6 to 1 (step S14). As a result, the manual steering command value generating unit 45 calculates the manual steering command value θ based on the equation (5). ＭＤ，ｃｍｄ After the process of step S14 is performed, the equation of motion setting unit 43D ends the process for the current calculation cycle.

[0288] In the following, "a state in which the vehicle is heading toward the departure-avoidance side" or "a state in which the vehicle is heading toward the departure side and is being steered intentionally by the driver" will be referred to as "first state." Also, "a state in which the vehicle is heading toward the departure side and is being steered due to the driver's inattention" will be referred to as "second state."

[0289] The motor control ECU 202D according to the fourth modification can set virtual spring reaction forces and virtual damper reaction forces suitable for the first state and the second state, respectively. This makes it possible to generate steering reaction forces suitable for the first state and the second state, respectively. In other words, the motor control ECU 202D according to the fourth modification can apply a steering reaction force to the driver in a new method in the driving assistance mode.

[0290] Specifically, in the second state and the lateral deviation e Ｌ Ga-e Ｌ，ｓ is greater than e Ｌ，ｓ When it is determined that the virtual damper reaction force and the virtual spring reaction force are smaller than those in the first state (LCA mode), the virtual damper reaction force and the virtual spring reaction force can be made larger than those in the first state.

[0291] Second state and lateral deviation e Ｌ Ga-e Ｌ，ｓ Below or e Ｌ，ｓ When it is determined that the lateral deviation e is equal to or greater than the predetermined value (in the LKA mode), the virtual damper reaction force can be made larger than that in the first state. Ｌ This allows the driver to easily recognize the distance from the center of the lane or the distance to the lane.

[0292] The contents explained in the above [Explanation of Modified Example of Coefficient / Weight Setting Process (Part 1)] can also be applied to the motor controlling ECU 202D according to the fourth modified example.

[0293] Furthermore, in the motor control ECU 202D according to the fourth modification, when it is determined in step S3 of FIG. 14A or step S9 of FIG. 14B that the steering is being performed due to carelessness of the driver, the equation of motion setting unit 43D sets the third weight W3 and the fifth weight W5 to 0, the fourth weight W4 and the sixth weight W6 to 1, and sets the first virtual load viscous damping coefficient cr(e Ｌ ) is the virtual load viscous damping coefficient c ｍｄ It may be set as follows.

[0294] That is, when it is determined that the vehicle is heading toward the departure side and the steering is being performed due to the driver's carelessness (second state) (NO in step S3 or step S9), the manual steering command value generating unit 45 calculates the lateral deviation e Ｌ Regardless of this, the manual steering command value θ ＭＤ，ｃｍｄ may be calculated.

[0295] [Explanation of Fifth Modification of Motor Control ECU] The manual steering command value generating unit 45A shown in Fig. 9 may be used instead of the manual steering command value generating unit 45 in Fig. 13. In this case, as shown by the broken line in Fig. 13, the manual steering command value generating unit 45A receives the automatic steering command value θ ＡＤ．ｃｍｄ is further input. A motor control ECU in which a manual steering command value generating unit 45A is used instead of the manual steering command value generating unit 45 in FIG. 13 will be referred to as a motor control ECU 202E according to a fifth modified example.

[0296] In the motor control ECU 202E according to the fifth modified example, the equation of motion setting unit 43D also performs the same coefficient / weight setting process as the coefficient / weight setting process described with reference to FIGS. 14A and 14B.

[0297] The contents explained in the above [Explanation of Modified Example of Coefficient / Weight Setting Process (Part 1)] can also be applied to the motor controlling ECU 202E according to the fifth modified example.

[0298] Furthermore, in the motor control ECU 202E according to the fifth modification, when it is determined in step S3 of FIG. 14A or step S9 of FIG. 14B that the steering is being performed due to the driver's carelessness, the equation of motion setting unit 43D sets the third weight W3 and the fifth weight W5 to 0, the fourth weight W4 and the sixth weight W6 to 1, and sets the first virtual load viscous damping coefficient cr(e Ｌ ) is the virtual load viscous damping coefficient c ｍｄ It may be set as follows.

[0299] That is, when it is determined that the vehicle is heading toward the departure side and the steering is being performed due to the driver's carelessness (second state) (NO in step S3 or step S9), the manual steering command value generating unit 45A calculates the lateral deviation e Ｌ Regardless of this, the manual steering command value θ ＭＤ，ｃｍｄ may be calculated.

[0300] Although the embodiment and the first to fifth modified examples of the motor control ECU of the present disclosure have been described above, the present disclosure can also be embodied in other forms.

[0301] In the above-described embodiment and the first to fifth modified examples of the motor control ECU, the lateral position of the vehicle is determined by the lateral deviation e, which is the distance from the center of the lane in which the vehicle is currently traveling to the vehicle reference position. Ｌ However, the distance from the boundary of the lane in which the vehicle is currently traveling (lane boundary) to the vehicle reference position may also be used as the vehicle lateral position.

[0302] In the above-described embodiment and the first to fifth modified examples of the motor control ECU, the assist torque command value T ａｓｓｔ is multiplied by the first weight W1, and the assist torque command value W1·T after multiplication by the first weight is ａｓｓｔ is given to the adder 50. However, instead of this, the manual steering command value θ ＭＤ，ｃｍｄ The manual torque command value corresponding to the torque command value may be multiplied by a first weight W1, and the manual torque command value after multiplication with the first weight W1 may be provided to the adder 50.

[0303] Although the above-described embodiment and the first to fifth modified examples of the motor control ECU have shown examples in which the present disclosure is applied to a column-type EPS, the present disclosure can also be applied to EPSs other than column-type EPSs. The present disclosure can also be applied to steer-by-wire systems.

[0304] Although the embodiments of the present disclosure have been described in detail, these are merely examples used to clarify the technical content of the present disclosure, and the present disclosure should not be construed as being limited to these examples, and the scope of the present disclosure is limited only by the appended claims.

[0305] 1... electric power steering device, 3... steered wheels, 4... steering mechanism, 18... electric motor, 43, 43B, 43D... equation of motion setting section, 44... assist torque command value setting section, 45, 45A... manual steering command value generation section, 46... integrated angle command value calculation section, 47... angle control section, 48... first weight multiplication section, 49... second weight multiplication section, 50... addition section, 51... torque control section, 52... weight setting section, 201... host ECU, 202, 202A to 202D... motor control ECUs

Claims

1. A motor control device including: a manual steering command value generation unit that generates a manual steering command value by using an equation of motion of a reference model of a steering device; an integrated angle command value calculation unit that calculates an integrated angle command value by adding the manual steering command value to an automatic steering command value given in a driving assistance mode; a control unit that controls the angle of an electric motor for steering angle control based on the integrated angle command value; and a motion equation setting unit that changes the motion equation in accordance with the lateral position of a vehicle reference position with respect to the driving lane and the time differential value of the actual steering angle or the time differential value of the manual steering command value.

2. A motor control device as described in claim 1, wherein the equation of motion includes a road reaction force characteristic coefficient, and the equation of motion setting unit changes the equation of motion by changing the value of at least one road reaction force characteristic coefficient included in the equation of motion.

3. The motor control device according to claim 1, wherein the equation of motion setting unit is configured to change the equation of motion by switching between a first equation of motion and a second equation of motion, and wherein the first equation of motion uses a target virtual spring reaction force corresponding to the lateral position as the virtual spring reaction force, and the second equation of motion uses a virtual spring reaction force that is set using a virtual load spring stiffness coefficient that is constant regardless of the lateral position as the virtual spring reaction force.

4. A motor control device as claimed in any one of claims 1 to 3, wherein the equation of motion setting unit is configured to determine whether the steering is being performed due to the driver's carelessness or the driver's intention based on the lateral position and the time derivative value of the actual steering angle, and to change the equation of motion based on the determination result.

5. A motor control device as described in claim 3, wherein the equation of motion setting unit determines whether the steering is being performed due to the driver's inattention or the driver's intention based on the lateral position and the time differential value of the actual steering angle, and when the equation of motion setting unit determines that the steering is being performed due to the driver's inattention, it sets the first equation of motion as the equation of motion, and when it determines that the steering is being performed due to the driver's intention, it sets the second equation of motion as the equation of motion.

6. A motor control device according to any one of claims 1 to 3, wherein the equation of motion setting unit is configured to determine whether the vehicle is heading toward the departure side or toward the departure avoidance side based on the lateral position and the time differential value of the manual steering command value, and to change the equation of motion based on the determination result.

7. A motor control device as described in claim 3, wherein the equation of motion setting unit determines whether the vehicle is heading toward the departure side or toward the departure avoidance side based on the lateral position and the time differential value of the manual steering command value, and when the vehicle is heading toward the departure side, sets the first equation of motion as the equation of motion, and when the vehicle is heading toward the departure avoidance side, sets the second equation of motion as the equation of motion.

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