Motor control device

Abstract

The invention relates to a motor control device. A motor control device includes: a manual steering command value generation unit that generates a manual steering command value using an equation of motion of a reference model of a steering device; an integrated angle command value calculation unit that adds the manual steering command value to an automatic steering command value provided during the driving support mode and calculates an integrated angle command value; a control unit that performs angle control on an electric motor for corner control on the basis of the integrated angle command value; and a motion equation setting unit that changes the motion equation on the basis of the time differential value of the angular deviation between the automatic steering command value and the actual steering angle.

Description

Technical Field

[0001] The present invention relates to a motor control device for driving and controlling an electric motor for steering angle control. Background Art

[0002] In Patent Document 1 below, a technique is disclosed in which a control gain (control amount) is changed according to the lateral displacement of the host vehicle from the center of the driving lane, the yaw angle of the host vehicle with respect to the driving lane, etc. Specifically, when the yaw angle is an angle at which the vehicle is oriented toward the deviation side, the control gain becomes large, and when the yaw angle is an angle at which the vehicle is oriented away from the deviation side, the control gain becomes small.

[0003] Patent Document 1: Japanese Unexamined Patent Application Publication No. 2009-208602

[0004] Patent Document 2: International Publication No. 2023 / 286169 Summary of the Invention

[0005] An object of one embodiment of the present invention 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.

[0006] One embodiment of the present invention provides a motor control device for driving and controlling an electric motor of a steering device, including: a manual steering command value generation unit that generates a manual steering command value using the equation of motion of a reference model of the steering device; a combined angle command value calculation unit that calculates a combined angle command value by adding the manual steering command value to an automatic steering command value provided in a driving assistance mode; a control unit that performs angle control on an electric motor for steering angle control based on the combined angle command value; and an equation of motion setting unit that changes the equation of motion according to a time derivative of an angle deviation between the automatic steering command value and an actual steering angle.

[0007] In this configuration, in a driving assistance mode, a steering reaction force can be applied to the driver in a new method.

[0008] The above object, another object, feature, and effect of the present invention will become clear from the description of the embodiments described below with reference to the drawings. Brief Description of the Drawings

[0009] Figure 1 It is a schematic diagram showing a schematic configuration of an electric power steering system to which the motor control device according to the first embodiment of the present invention is applied.

[0010] Figure 2 It is a block diagram showing an electrical configuration of an ECU for motor control.

[0011] Figure 3 represents the auxiliary torque command value T tb relative to the torsion bar torque T asst in the form of a setting example diagram.

[0012] Figure 4 is a schematic diagram showing an example of a reference EPS model used in the manual steering operation command value generation unit.

[0013] Figure 5 is a block diagram showing the structure of the angle control unit.

[0014] Figure 6 is a schematic diagram showing a structural example of the physical model of the electric power steering system.

[0015] Figure 7 is a block diagram showing the structure of the disturbance torque estimation unit.

[0016] Figure 8 is a schematic diagram showing the structure of the torque control unit.

[0017] Figure 9 is a flowchart showing the steps of the weight setting process performed by the weight setting unit in the driving assistance mode.

[0018] Figure 10 represents the first imaginary load spring stiffness coefficient kr(e L ) and the second imaginary load spring stiffness coefficient kg L relative to the lateral deviation e

[0019] Figure 11 in the form of a setting example diagram. L represents the imaginary load viscous damping coefficient c(e L ) relative to the lateral deviation e

[0020] Figure 12A 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. Figure 12B represents the actual steering angle θ and the automatic steering operation command value θ AD，cmd both have positive signs, and when the actual steering angle θ is greater than the automatic steering operation command value θ AD，cmd in the form of a schematic diagram showing an example of the angle deviation Δθ. Figure 12C represents the case where the sign of the actual steering angle θ is negative and the sign of the automatic steering operation command value θ AD，cmd is positive, and the angle deviation Δθ A- in the form of a schematic diagram showing an example.

[0021] Figure 13It is a flowchart showing the steps of the spring rigidity coefficient setting process performed by the road surface reaction force characteristic setting unit in the driving assistance mode.

[0022] Figure 14 It represents the first imaginary load viscous damping coefficient cr(e L ) and the second imaginary load viscous damping coefficient cg with respect to the lateral deviation e L A chart showing the setting examples.

[0023] Figure 15 It is a flowchart showing the steps of the road surface reaction force characteristic setting process performed by the road surface reaction force characteristic setting unit of the first modification example in the driving assistance mode.

[0024] Figure 16 It is a flowchart showing the steps of the viscous damping coefficient setting process performed by the road surface reaction force characteristic setting unit of the second modification example in the driving assistance mode.

[0025] Figure 17 It is a flowchart showing the steps of the road surface reaction force characteristic setting process performed by the road surface reaction force characteristic setting unit in the driving assistance mode in the third embodiment.

[0026] Figure 18 It is a flowchart showing the steps of the road surface reaction force characteristic setting process performed by the road surface reaction force characteristic setting unit in the driving assistance mode in the fourth embodiment.

[0027] Figure 19 It is a block diagram showing the first modification example of the motor control ECU.

[0028] Figure 20 It represents the target imaginary spring reaction force T L with respect to the lateral deviation e tb，d (e L ) A chart showing the setting examples.

[0029] Figure 21 It represents the first imaginary load spring rigidity coefficient kr and the second imaginary load spring rigidity coefficient kg with respect to the lateral deviation e L A chart showing the setting examples.

[0030] Figure 22 It represents the first imaginary load viscous damping coefficient cr(e L ) and the second imaginary load viscous damping coefficient cg with respect to the lateral deviation e L A chart showing the setting examples.

[0031] Figure 23It is a schematic diagram showing an example of a reference EPS model used in a manual steering operation command value generation unit described in International Publication No. 2023 / 286169.

[0032] Figure 24 It is a block diagram showing the structure of a manual steering operation command value generation unit which is a first modification example of an ECU for motor control.

[0033] Figure 25A It is a part of a flowchart showing the steps of coefficient / weight setting processing performed by a motion equation setting unit in a driving assistance mode.

[0034] Figure 25B It is a part of a flowchart showing the steps of coefficient / weight setting processing performed by a motion equation setting unit in a driving assistance mode.

[0035] Figure 26 It is a block diagram showing the structure of a manual steering operation command value generation unit which is a second modification example of an ECU for motor control. Detailed Description of the Invention

[0036] [Description of Embodiments of the Present Invention]

[0037] One embodiment of the present invention provides a motor control device for driving and controlling an electric motor of a steering device, which includes: a manual steering operation command value generation unit that generates a manual steering operation command value by using a motion equation of a reference model of the steering device; a combined angle command value calculation unit that calculates a combined angle command value by adding the manual steering operation command value to an automatic steering operation command value provided in a driving assistance mode; a control unit that performs angle control on the electric motor for cornering control based on the combined angle command value; and a motion equation setting unit that changes the motion equation according to a time differential value of an angle deviation between the automatic steering operation command value and an actual steering operation angle.

[0038] In this structure, in a driving assistance mode, a steering operation reaction force can be applied to a driver in a new method.

[0039] In one embodiment of the present invention, the motion equation includes a road surface reaction force characteristic coefficient, and the motion equation setting unit changes the motion equation by changing a value of at least one road surface reaction force characteristic coefficient included in the motion equation.

[0040] In one embodiment of the present invention, the motion equation setting unit is configured to change the motion equation by switching between a first motion equation and a second motion equation. In the first motion equation, a target imaginary spring reaction force corresponding to the lateral position of the vehicle reference position with respect to the driving lane is used as the imaginary spring reaction force. In the second motion equation, an imaginary spring reaction force set with an imaginary load spring stiffness coefficient that uses a constant value regardless of the lateral position is used as the imaginary spring reaction force.

[0041] In one embodiment of the present invention, the motion equation setting unit is configured to determine whether the vehicle is in a state of moving towards the deviation side or a state of moving towards avoiding the deviation side based on either the lateral position of the vehicle reference position with respect to the driving lane or the angle deviation, and the time differential value, and change the motion equation based on the determination result.

[0042] In one embodiment of the present invention, the motion equation setting unit determines whether the vehicle is in a state of moving towards the deviation side or a state of moving towards avoiding the deviation side based on either the lateral position of the vehicle reference position with respect to the driving lane or the angle deviation, and the time differential value. In the state where the vehicle is moving towards avoiding the deviation side, the value of at least one of the road surface reaction force characteristic coefficients included in the motion equation is reduced compared to the state where the vehicle is moving towards the deviation side.

[0043] In one embodiment of the present invention, the motion equation setting unit determines whether the vehicle is in a state of moving towards the deviation side or a state of moving towards avoiding the deviation side based on either the lateral position of the vehicle reference position with respect to the driving lane or the angle deviation, and the time differential value. In the state where the vehicle is moving towards the deviation side, at least one of the road surface reaction force characteristic coefficients included in the motion equation is changed according to the lateral position.

[0044] In one embodiment of the present invention, the motion equation setting unit uses the time differential value to determine whether the vehicle is in a state of moving towards the deviation side or a state of moving towards avoiding the deviation side. In the state where the vehicle is moving towards the deviation side, the first motion equation is set as the motion equation. In the state where the vehicle is moving towards avoiding the deviation side, the second motion equation is set as the motion equation.

[0045] [Detailed description of the embodiments of the present invention]

[0046] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

[0047] Figure 1 It is a schematic diagram showing a brief structure of an electric power steering system of a steering control device to which the first embodiment of the present invention is applied.

[0048] The electric power steering system 1 includes: a steering wheel (steering gear) 2 as a steering control component for steering a vehicle, a steering mechanism 4 that steers the steering wheels 3 in linkage with the rotation of the steering wheel 2, and a steering control assist mechanism 5 for assisting the driver's steering control. The steering wheel 2 and the steering mechanism 4 are mechanically connected via a steering shaft 6 and an intermediate shaft 7.

[0049] 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 relatively rotatable.

[0050] A torque sensor 12 is disposed near the torsion bar 10. The torque sensor 12 detects the torsion bar torque T applied to the steering wheel 2 based on the relative rotational displacement amount between the input shaft 8 and the output shaft 9 tb . In this embodiment, the torsion bar torque T detected by the torque sensor 12 tb , for example, detects the torque for steering in the left direction as a positive value, and detects the torque for steering in the right direction as a negative value. The larger the absolute value, the larger the magnitude of the torsion bar torque T tb . The torsion bar torque T tb is an example of the "steering control torque" of the present invention.

[0051] The steering mechanism 4 is composed of a rack and pinion mechanism including a pinion shaft 13 and a rack shaft 14 as a steering shaft. Steering wheels 3 are connected to both ends of the rack shaft 14 via tie rods 15 and steering knuckle arms (not shown). The pinion shaft 13 is connected to the intermediate shaft 7. The pinion shaft 13 rotates in linkage with the steering control of the steering wheel 2. A pinion 16 is connected to the front end of the pinion shaft 13.

[0052] The rack shaft 14 extends linearly in the left - right direction of the vehicle. A rack 17 meshing with the pinion 16 is formed in the middle part of the axial direction of the rack shaft 14. Through the pinion 16 and the rack 17, the rotation of the pinion shaft 13 is converted into the axial movement of the rack shaft 14. By moving the rack shaft 14 axially, the steering wheels 3 can be steered.

[0053] If 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. Moreover, the rotation of the pinion shaft 13 is converted into the axial movement of the rack shaft 14 through the pinion 16 and the rack 17. Thereby, the steering wheels 3 are steered.

[0054] The steering assist mechanism 5 includes an electric motor 18 for generating a steering assist force (assist torque), and a speed reducer 19 for amplifying the output torque of the electric motor 18 and transmitting it to the steering mechanism 4. The speed reducer 19 is constituted by a worm gear mechanism including a worm 20 and a worm wheel 21 meshing with the worm 20. The speed reducer 19 is housed in a gear housing 22 which is a transmission mechanism housing.

[0055] Hereinafter, the reduction ratio (transmission ratio) of the speed reducer 19 is often denoted by N. The reduction ratio N is defined as the ratio of the rotation angle of the worm 20, that is, the worm angle θ wg to the rotation angle of the worm wheel 21 and the worm wheel angle θ ww (θ wg / θ ww ).

[0056] The worm 20 is rotationally driven by the electric motor 18. In addition, the worm wheel 21 is connected to the output shaft 9 so as to be rotatable integrally.

[0057] If the worm 20 is rotationally driven by the electric motor 18, the worm wheel 21 is rotationally driven, a motor torque is applied to the steering shaft 6 and the steering shaft 6 (output shaft 9) is rotated. Moreover, the rotation of the steering shaft 6 is transmitted to the pinion shaft 13 via the intermediate shaft 7. The rotation of the pinion shaft 13 is converted into an axial movement of the rack shaft 14. Thereby, the steering wheel 3 is steered. That is, by rotationally driving the worm 20 by the electric motor 18, steering assist based on the electric motor 18 and steering of the steering wheel 3 can be performed. A rotation angle sensor 23 for detecting the rotation angle of the rotor of the electric motor 18 is provided in the electric motor 18.

[0058] As the torque applied to the output shaft 9 (an example of the drive object of the electric motor 18), there are a motor torque by the electric motor 18 and a disturbance torque T other than the motor torque lc . The disturbance torque T other than the motor torque lc includes a torsion bar torque T tb , a road surface load torque (road surface reaction torque) T rl , a friction torque T f , etc.

[0059] The torsion bar torque T tb is a torque applied from the steering wheel 2 side to the output shaft 9 by the force applied by the driver to the steering wheel 2, the force generated by steering inertia, etc.

[0060] The road surface load torque T rl is a torque applied from the steering wheel 3 side to the output shaft 9 via the rack shaft 14 by the self-aligning torque generated by the tire, the force generated by the suspension, tire wheel alignment, the frictional force of the rack and pinion mechanism, etc.

[0061] The vehicle is equipped with a CCD (Charge Coupled Device) camera 25 that photographs the road ahead in the traveling direction of the vehicle; a GPS (Global Positioning System) 26 for detecting the position of the vehicle itself; a radar 27 for detecting the road shape and obstacles; a map information memory 28 for storing map information; and a vehicle speed sensor 29.

[0062] The CCD camera 25, GPS 26, radar 27, map information memory 28, and vehicle speed sensor 29 are connected to a host ECU (ECU: Electronic Control Unit) 201 for performing driving assistance control. The host ECU 201 performs surrounding environment recognition, vehicle position estimation, path planning, etc. based on the information obtained from the CCD camera 25, GPS 26, radar 27, and vehicle speed sensor 29, as well as the map information, and determines the control target values for steering operation and driving actuators.

[0063] In this embodiment, as driving modes, there are a normal mode and a driving assistance mode. When in the driving assistance mode, the host ECU 201 sets an automatic steering operation command value θ AD，cmd . The automatic steering operation command value θ AD，cmd is the target value of the steering angle for causing the vehicle to travel along the target travel route.

[0064] In this embodiment, the driving assistance is lane keeping assistance (LKA) for preventing the vehicle from deviating from the lane. The driving assistance may also be lane centering assistance (LKA) that assists the steering operation in such a way that the vehicle travels in the center of the driving lane. The driving assistance may also include lane keeping assistance (LKA) and lane centering assistance (LKA) as in the modification example of the motor control ECU described later.

[0065] In this embodiment, the automatic steering operation command value θ AD，cmd is represented by the rotation amount (rotation angle) of the output shaft 9 from the neutral position. The rotation amount in the left steering operation direction from the neutral position is represented as a positive value, and the rotation amount in the right steering operation direction from the neutral position is represented as a negative value. The automatic steering operation command value θ AD，cmd is set, for example, based on the lateral deviation with respect to the vehicle speed and the target travel route (center line of the lane) and the yaw deviation of the vehicle with respect to the target travel route. The process of setting such an automatic steering operation command value θ AD，cmd is well-known, so detailed description is omitted here.

[0066] In addition, the host ECU 201 outputs a mode signal S indicating whether the driving mode is the normal mode or the driving assistance mode mode and a lateral deviation e from the target driving route L . In this embodiment, the lateral deviation e L is the distance from the target driving route to the reference position of the vehicle (hereinafter referred to as the "vehicle reference position"). The vehicle reference position is set to a specified position at the center of the width of the vehicle

[0067] In this embodiment, the lateral deviation e L is 0 (e L = 0) when the vehicle reference position is on the target driving route, a positive value (e L > 0) when the vehicle reference position is on the left side of the target driving route in the traveling direction, and a negative value (e L < 0) when the vehicle reference position is on the right side of the target driving route in the traveling direction. The lateral deviation e L is an example of the "lateral position of the vehicle reference position with respect to the driving lane" of the present invention

[0068] The mode signal S mode , the automatic steering operation command value θ AD，cmd , the lateral deviation e L and the vehicle speed V are provided to the motor control ECU 202 via the in-vehicle network. The torsion bar torque T detected by the torque sensor 12 tb , the output signal of the rotation angle sensor 23 are input to the motor control ECU 202. The motor control ECU 202 controls the electric motor 18 based on the above input signals and the information provided from the host ECU 201

[0069] Figure 2 is a block diagram showing the electrical structure of the motor control ECU 202

[0070] Hereinafter, the operation in the case where the driving mode is the driving assistance mode will be mainly described

[0071] The motor control ECU 202 includes a microcomputer 40, a drive circuit (inverter circuit) 31 controlled by the microcomputer 40 and supplying power to the electric motor 18, and a current detection circuit 32 for detecting the current flowing through the electric motor 18 (hereinafter referred to as the "motor current I m ").

[0072] The microcomputer 40 includes a CPU and memories (ROM, RAM, non-volatile memories, etc.), and functions as a plurality of functional processing units by executing a prescribed program. The plurality of functional processing units include a rotational angle calculation unit 41, a reduction ratio division unit 42, a road surface reaction force characteristic setting unit 43, an assist torque command value setting unit 44, a manual steering operation command value generation unit 45, a comprehensive angle command value calculation unit 46, an angle control unit 47, a first weight multiplication unit 48, a second weight multiplication unit 49, an addition unit 50, a torque control unit (current control unit) 51, and a weight setting unit 52.

[0073] The rotational angle calculation unit 41 calculates the rotational angle θ of the rotor of the electric motor 18 based on the output signal of the rotational angle sensor 23. m . The reduction ratio division unit 42 divides the rotor rotational angle θ m by the reduction ratio N, and converts the rotor rotational angle θ m into the rotational angle (actual steering operation angle) θ of the output shaft 9. In this embodiment, the actual steering operation angle θ is represented by the amount of rotation (rotational angle) starting from the neutral position of the output shaft 9. The amount of rotation in the left steering operation direction from the neutral position is represented as a positive value, and the amount of rotation in the right steering operation direction from the neutral position is represented as a negative value.

[0074] The road surface reaction force characteristic setting unit 43 sets the imaginary load spring stiffness coefficient k and the imaginary load viscous coefficient c used by the manual steering operation command value generation unit 45. The road surface reaction force characteristic setting unit 43 is an example of the "equation of motion setting unit" of the present invention. Details of the operation of the road surface reaction force characteristic setting unit 43 will be described later.

[0075] The assist torque command value setting unit 44 sets the target value of the assist torque required for manual operation, that is, the assist torque command value T asst . The assist torque command value setting unit 44 sets the assist torque command value T tb based on the vehicle speed V provided by the upper ECU 201 and the torsion bar torque T detected by the torque sensor 12 asst . In Figure 3 shows a setting example of the assist torque command value T tb with respect to the torsion bar torque T asst .

[0076] The assist torque command value T asst is set to a positive value when a steering assist force for left-direction steering operation should be generated from the electric motor 18, and is set to a negative value when a steering assist force for right-direction steering operation should be generated from the electric motor 18. The assist torque command value T asst with respect to the torsion bar torque T tbThe positive value is set to be positive, relative to the torsion bar torque T tb and the negative value is set to be negative.

[0077] The assist torque command value T asst is set to the absolute value of the torsion bar torque T tb such that the larger its absolute value, the larger its absolute value, and is set such that the larger the vehicle speed V, the smaller its absolute value.

[0078] In addition, the assist torque command value setting unit 44 may also operate the assist torque command value T tb by multiplying the torsion bar torque T asst .

[0079] The manual steering operation command value generation unit 45 is provided to set the steering operation angle corresponding to the steering wheel operation (more precisely, the rotation angle θ of the output shaft 9) as the manual steering operation command value θ MD，cmd when the driver operates the steering wheel 2. The manual steering operation command value generation unit 45 uses the torsion bar torque T detected by the torque sensor 12 tb , the assist torque command value T set by the assist torque command value setting unit 44 asst , the imaginary load spring stiffness coefficient k and the imaginary load viscous damping coefficient c set by the road surface reaction force characteristic setting unit 43 to generate the manual steering operation command value θ MD，cmd . Details of the manual steering operation command value generation unit 45 will be described later.

[0080] The combined angle command value calculation unit 46 adds the automatic steering operation command value θ set by the upper ECU 201 AD，cmd to the manual steering operation command value θ MD，cmd to calculate the combined angle command value θ int，cmd .

[0081] The angle control unit 47 calculates the combined motor torque command value T corresponding to the combined angle command value θ int，cmd based on the combined angle command value θ int，cmd . Details of the angle control unit 47 will be described later. mint，cmd

[0082] The first weight multiplication unit 48 multiplies the assist torque command value T set by the assist torque command value setting unit 44 asst by the first weight W1. The second weight multiplication unit 49 multiplies the combined motor torque command value T mint，cmd by the second weight W2. The first weight W1 and the first weight W2 are set by the weight setting unit 52. Details of the weight setting unit 52 will be described later.

[0083] ​The adder 50 calculates the motor torque command value T for the electric motor 18 by adding the auxiliary torque command value W1·T after being multiplied by the first weight (after the first weighting process) asst and the integrated motor torque command value W2·T after being multiplied by the second weight (after the second weighting process). mint，cmd m，cmd m，cmd

[0084] The torque control unit 51 drives the drive circuit 31 in such a way that the motor torque of the electric motor 18 approaches the motor torque command value T. m，cmd

[0085]

[0085] In this embodiment, the manual steering operation command value generation unit 45 uses a reference EPS model to set the manual steering operation command value θ. MD，cmd

[0086] Figure 4 is a schematic diagram showing an example of the reference EPS model used in the manual steering operation command value generation unit 45.

[0087] Figure 4 The reference EPS model of is an example of the "reference model of the steering device" of the present invention. This reference EPS model is a single inertia model including the lower column. The lower column corresponds to the output shaft 9 and the worm gear 21. In Figure 4 J ref is the inertia of the lower column, and T tb is the torsion bar torque. A torsion bar torque T tb , an auxiliary torque N·T acting on the output shaft 9 from the electric motor 18 asst and a road surface load torque T rl are applied to the lower column. If the rotation angle of the lower column is set as the manual steering operation command value θ MD，cmd , the imaginary road surface load torque (imaginary road surface reaction force) T rl uses the imaginary load spring stiffness coefficient k, the imaginary load viscous damping coefficient c, and the manual steering operation command value θ MD，cmd and is represented by the following formula (1).

[0088] T r1 = -k·θ MD，cmd - c(dθ MD，cmd / dt)…(1)

[0089] The equation of motion of the reference EPS model is represented by the following formula (2).

[0090] J ref ·d 2 θ MD,cmd / dt 2 = T tb + N·T​​asst -k·θ MD，cmd -c(dθ MD,cmd / dt)…(2)

[0091] The values of the virtual load spring stiffness coefficient k and the virtual load viscous damping coefficient c are set by the road surface reaction force characteristic setting unit 43. The virtual load spring stiffness coefficient k and the virtual load viscous damping coefficient c, which are the coefficients of the equation of motion in Equation (2), are an example of the "road surface reaction force characteristic coefficients" of the present invention.

[0092] The manual steering operation command value generation unit 45 substitutes the torsion bar torque T detected by the torque sensor 12 tb into T tb , and substitutes the assist torque command value T asst set by the assist torque command value setting unit 44 into T asst , and solves the differential equation of Equation (2), thereby calculating the manual steering operation command value θ MD，cmd .

[0093] Figure 5 is a block diagram showing the structure of the angle control unit 47.

[0094] The angle control unit 47 calculates the integrated motor torque command value T int，cmd based on the integrated angle command value θ mint，cmd . The angle control unit 47 includes a low-pass filter (LPF) 61, a feedback control unit 62, a feedforward control unit 63, a disturbance torque estimation unit 64, a torque addition unit 65, a disturbance torque compensation unit 66, a reduction ratio division unit 67, and a reduction ratio multiplication unit 68.

[0095] The reduction ratio multiplication unit 68 multiplies the motor torque command value T Figure 2 calculated by the addition unit 50 (see m，cmd ) by the reduction ratio N of the speed reducer 19, thereby converting the motor torque command value T m，cmd into the output shaft torque command value N·T m，cmd acting on the output shaft 9 (worm wheel 21).

[0096] The low-pass filter 61 performs low-pass filtering on the integrated angle command value θ int，cmd . The integrated angle command value θ intL，cmd after low-pass filtering is provided to the feedback control unit 62 and the feedforward control unit 63.

[0097] The feedback control unit 62 is configured to make the steering operation angle estimation value ^θ calculated by the disturbance torque estimation unit 64 equal to the integrated angle command value θ intL，cmdis set close to it. The feedback control unit 62 includes an angular deviation calculation unit 62A and a PD control unit 62B. The angular deviation calculation unit 62A calculates the deviation Δθ of the combined angular command value θ intL，cmd from the steering angle estimation value ^θ (Δθ = θ intL，cmd – ^θ). In addition, the angular deviation calculation unit 62A may also calculate the combined angular command value θ as the angular deviation Δθ intL，cmd , and the deviation (θ Figure 2 ) from the actual steering angle θ calculated by the reduction ratio division unit 42 (refer to intL，cmd -θ).

[0098] The PD control unit 62B calculates the feedback control torque T fb by performing PD operation (proportional derivative operation) on the angular deviation Δθ calculated by the angular deviation calculation unit 62A. The feedback control torque T fb is provided to the torque addition unit 65.

[0099] The feedforward control unit 63 is provided to compensate for the response delay caused by the inertia of the electric power steering system 1 and improve the response of the control. The feedforward control unit 63 includes an angular acceleration calculation unit 63A and an inertia multiplication unit 63B. The angular acceleration calculation unit 63A calculates the target angular acceleration d intL，cmd by performing second-order differentiation on the combined angular command value θ 2 θ intL，cmd / dt 2 .

[0100] The inertia multiplication unit 63B calculates the feedforward control torque T 2 θ intL，cmd / dt 2 by multiplying the target angular acceleration d ff calculated by the angular acceleration calculation unit 63A by the inertia J of the electric power steering system 1, and calculates T 2 θ intL，cmd / dt 2 ). The inertia J is obtained, for example, from the physical model of the electric power steering system 1 described later (refer to Figure 6 ). The feedforward control torque T ff is provided to the torque addition unit 65 as an inertia compensation value.

[0101] The torque addition unit 65 calculates the basic torque command value (T fb + T ff ) by adding the feedback control torque T fb to the feedforward control torque T ff .

[0102] The disturbance torque estimation unit 64 is provided to estimate the non-linear torque (disturbance torque: torque other than the motor torque) generated as a disturbance to the device (the control target of the electric motor 18). The disturbance torque estimation unit 64 estimates the disturbance torque (disturbance load) T m，cmd based on the output shaft torque command value N·T lc , the actual steering angle θ, and the steering angle differential value (angular velocity) dθ / dt. The estimated values of the disturbance torque T lc , the steering angle θ, and the steering angle differential value (angular velocity) dθ / dt are represented by ^T lc , ^θ, and d^θ / dt, respectively. Details of the disturbance torque estimation unit 64 will be described later.

[0103] The estimated disturbance torque value ^T calculated by the disturbance torque estimation unit 64 lc is provided to the disturbance torque compensation unit 66 as a disturbance torque compensation value. The estimated steering angle value ^θ calculated by the disturbance torque estimation unit 64 is provided to the angle deviation calculation unit 62A.

[0104] The disturbance torque compensation unit 66 calculates the combined steering torque command value T fb by subtracting the estimated disturbance torque value ^T ff from the basic torque command value (T lc +T sint，cmd ). Thus, the combined steering torque command value T fb compensated for the disturbance torque is obtained (the torque command value for the output shaft 9). ff -^T lc ). sint，cmd (with respect to the torque command value for the output shaft 9).

[0105] The combined steering torque command value T sint，cmd is provided to the reduction ratio division unit 67. The reduction ratio division unit 67 calculates the combined motor torque command value T sint，cmd by dividing the combined steering torque command value T mint，cmd by the reduction ratio N. This combined motor torque command value T mint，cmd is provided to the second weight multiplication unit 49 (see Figure 2 ).

[0106] The disturbance torque estimation unit 64 will be described in detail. The disturbance torque estimation unit 64 is configured, for example, with a disturbance observer that uses the physical model 101 of the electric power steering system 1 shown in Figure 6 to estimate the disturbance torque T lc , the steering angle θ, and the angular velocity dθ / dt.

[0107] The physical model 101 includes: a device (an example of a motor-driven object) 102 having an output shaft 9 and a worm gear 21 fixed to the output shaft 9. A torsion bar torque T is applied to the device 102 from the steering wheel 2 via the torsion bar 10 tb , and a road surface load torque T is applied to the device 102 from the steering wheel 3 side rl .

[0108] Also, an output shaft torque command value N·T is applied to the device 102 via the worm 20 m，cmd , and a frictional torque T is applied to the device 102 due to the friction between the worm gear 21 and the worm 20 f .

[0109] If the inertia of the device 102 is set to J, the equation of motion for the inertia of the physical model 101 is represented by the following equation (3).

[0110] [Mathematical formula 1]

[0111]

[0112] T lc = T tb + T rl + T f

[0113] d 2 θ / dt 2 is the angular acceleration of the device 102. N is the reduction ratio of the speed reducer 19. T lc represents the disturbance torque other than the motor torque applied to the device 102. In this embodiment, the disturbance torque T lc is expressed as the sum of the torsion bar torque T tb , the road surface load torque T rl and the frictional torque T f , but actually the disturbance torque T lc includes torques other than them.

[0114] For Figure 6 , the state equation of the physical model 101 is represented by the following equation (4).

[0115] [Mathematical formula 2]

[0116]

[0117] In the above equation (4), x is the state variable vector, u1 is the known input vector, u2 is the unknown input vector, and y is the output vector (measurement value). Also, in the above equation (4), A is the system matrix, B1 is the first input matrix, B2 is the second input matrix, C is the output matrix, and D is the direct transmission matrix.

[0118] Extend the above state equation to a system that includes an unknown input vector u2 as one of the states. The state equation of the extended system (extended state equation) is represented by the following equation (5).

[0119] [Equation 3]

[0120]

[0121] In the above equation (5), x e is the state variable vector of the extended system, which is represented by the following equation (6).

[0122] [Equation 4]

[0123]

[0124] In the above equation (5), A e is the system matrix of the extended system, B e is the known input matrix of the extended system, and Ce is the output matrix of the extended system.

[0125] Construct a disturbance observer (extended state observer) represented by the equation of the following equation (7) according to the extended state equation of the above equation (5).

[0126] [Equation 5]

[0127]

[0128] In equation (7), ^x e shows the estimated value of x e . In addition, L is the observer gain. In addition, ^y shows the estimated value of y. ^x e is represented by the following equation (8).

[0129] [Equation 6]

[0130]

[0131] In equation (8), ^θ is the estimated value of θ, and ^T lc is the estimated value of T lc .

[0132] The disturbance torque estimation unit 64 calculates the state variable vector ^x e based on the equation of the above equation (7).

[0133] Figure 7 is a block diagram showing the structure of the disturbance torque estimation unit 64.

[0134] The disturbance torque inference unit 64 includes an input vector input unit 71, an output matrix multiplication unit 72, a first addition unit 73, a gain multiplication unit 74, an input matrix multiplication unit 75, a system matrix multiplication unit 76, a second addition unit 77, an integration unit 78, and a state variable vector output unit 79.

[0135] The output shaft torque command value N·T Figure 5 calculated by the reduction ratio multiplication unit 68 (refer to m，cmd ) is supplied to the input vector input unit 71. The input vector input unit 71 outputs an input vector u1.

[0136] The output of the integration unit 78 becomes the state variable vector ^x e (refer to the above formula (8)). At the start of the calculation, an initial value is assigned as the state variable vector ^x e . The initial value of the state variable vector ^x e is, for example, 0.

[0137] The system matrix multiplication unit 76 multiplies the state variable vector ^x e by the system matrix A e . The output matrix multiplication unit 72 multiplies the state variable vector ^x e by the output matrix C e .

[0138] The first addition unit 73 subtracts the output (C Figure 2 ) of the output matrix multiplication unit 72 from the actual steering angle θ, which is the output vector (measured value) y calculated by the reduction ratio division unit 42 (refer to e ·^x e ). That is, the first addition unit 73 calculates the difference (y - ^y) between the output vector y and the output vector estimated value ^y (= C e ·^x e ). The gain multiplication unit 74 multiplies the output (y - ^y) of the first addition unit 73 by the observer gain L (refer to the above formula (7)).

[0139] The input matrix multiplication unit 75 multiplies the input vector u1 output from the input vector input unit 71 by the input matrix B e . The second addition unit 77 calculates the differential value d^x e / dt of the state variable vector by adding the output (Be·u1) of the input matrix multiplication unit 75, the output (A e ·^x e ) of the system matrix multiplication unit 76, and the output (L(y - ^y)) of the gain multiplication unit 74. The integration unit 78 calculates the state variable vector ^x e / dt by integrating the output (d^x e. The state variable vector output unit 79 calculates the disturbance torque estimation value ^T e , the steering angle estimation value ^θ, and the angular velocity estimation value d^θ / dt based on the state variable vector ^x. lc

[0140] Different from the above-mentioned extended state observer, a general disturbance observer is composed of an inverse model of the device and a low-pass filter. The equation of motion of the device is represented by Equation (3) as described above. Therefore, the inverse model of the device becomes the following Equation (9).

[0141] [Mathematical formula 7]

[0142]

[0143] The input of the general disturbance observer is J·d 2 θ / dt 2 and N·T m，cmd . Using the second derivative value of the actual steering angle θ, it is greatly affected by the noise of the rotation angle sensor 23. In contrast, in the extended state observer of the above embodiment, the disturbance torque is estimated in an integral form, so the noise influence caused by differentiation can be reduced.

[0144] In addition, as the disturbance torque estimation unit 64, a general disturbance observer composed of an inverse model of the device and a low-pass filter can also be used.

[0145] Figure 8 is a schematic diagram showing the structure of the torque control unit 51.

[0146] The torque control unit 51 (refer to Figure 2 ) includes a motor current command value calculation unit 81, a current deviation calculation unit 82, a PI control unit 83, and a PWM (Pulse Width Modulation) control unit 84.

[0147] The motor current command value calculation unit 81 calculates the motor current command value I by dividing the motor torque command value T Figure 2 calculated by the adder 50 (refer to m，cmd ) by the torque constant Kt of the electric motor 18. m，cmd .

[0148] The current deviation calculation unit 82 calculates the deviation ΔI (= I m，cmd - I m ) between the motor current command value I m，cmd obtained by the motor current command value calculation unit 81 and the motor current I m detected by the current detection circuit 32.

[0149] The PI control unit 83 generates, through PI operation (proportional-integral operation) on the current deviation ΔI calculated by the current deviation calculation unit 82, a drive command value for guiding the motor current I flowing through the electric motor 18 m to the motor current command value I m，cmd The PWM control unit 84 generates a PWM control signal with a duty ratio corresponding to the above drive command value and supplies it to the drive circuit 31. Thereby, electric power corresponding to the drive command value is supplied to the electric motor 18.

[0150] Figure 9 is a flowchart showing the steps of the weight setting process performed by the weight setting unit 52 in the driving assistance mode.

[0151] If the driving mode becomes the driving assistance mode, the weight setting unit 52 sets the first weight W1 to 1 and the second weight W2 to 0 (step S1). Thereby, the control mode of the electric motor 18 becomes the first control mode in which the electric motor 18 is driven and controlled only by the auxiliary torque command value T asst to drive and control the electric motor 18.

[0152] In addition, if the driving mode becomes the driving assistance mode, the upper ECU 201 sets the automatic steering operation command value θ AD，cmd , and this automatic steering operation command value θ AD，cmd , the mode signal S mode and the lateral deviation e L are provided to the motor control ECU 202.

[0153] Next, the weight setting unit 52 discriminates whether the absolute value |e L | of the lateral deviation e L | is greater than a specified value α (step S2). The specified value α is a value greater than 0, and is set, for example, to a value within the range of 0.2 m or more and 1.75 m or less.

[0154] When the absolute value |e L | of the lateral deviation e L | is α or less, (step S2: NO), that is, when the distance between the vehicle reference position and the center of the lane is α or less, the weight setting unit 52 returns to step S2.

[0155] In step S2, when it is discriminated that the absolute value |e L | of the lateral deviation e LWhen it is greater than α (Step S2: Yes), that is, when the distance between the vehicle reference position and the center of the lane is greater than α, the weight setting unit 52 sets the first weight W1 to 0 and sets the second weight W2 to 1 (Step S3). At this time, preferably, the weight setting unit 52 decreases the first weight W1 from 1 to 0 and increases the second weight W2 from 0 to 1. The time for decreasing the first weight W1 from 1 to 0 (the time for increasing the second weight W2 from 0 to 1) may be about 0.1 second, for example.

[0156] Thereby, the control mode of the electric motor 18 becomes the second control mode for driving and controlling the electric motor 18 by synthesizing the motor torque command value T mint，cmd During the period when the first weight W1 is being decreased (the period when the second weight W2 is being increased), based on the auxiliary torque command value W1·T after multiplying by the first weight asst and the synthesized motor torque command value w2·T after multiplying by the second weight mint，cmd the sum of which is used to control the electric motor 18.

[0157] In the second control mode, based on the manual steering operation command value θ MD，cmd and the automatic steering operation command value θ AD，cmd the sum of which, that is, the synthesized angle command value θ int，cmd is used to control the electric motor 18. Therefore, the steering reaction force reflecting the imaginary road surface load torque T MD，cmd based on the operation for the manual steering operation command value θ rl is reflected.

[0158] Next, the weight setting unit 52 determines whether the absolute value |e L | of the lateral deviation e L is α or less (Step S4).

[0159] When the absolute value |e L | of the lateral deviation e L is greater than α (Step S4: No), the weight setting unit 52 returns to Step S4.

[0160] In Step S4, when it is determined that the absolute value |e L | of the lateral deviation e L is α or less (Step S4: Yes), the weight setting unit 52 sets the first weight W1 to 1 and sets the second weight W2 to 0 (Step S5). At this time, the weight setting unit 52 increases the first weight W1 from 0 to 1 and decreases the second weight W2 from 1 to 0. The time for increasing the first weight W1 from 0 to 1 (the time for decreasing the second weight W2 from 1 to 0) may be about 0.1 second, for example.

[0161] Accordingly, the control mode of the electric motor 18 becomes the first control mode. In addition, during the period when the first weight W1 is incremented (the period when the second weight W2 is decremented), based on the auxiliary torque command value W1·T after multiplying by the first weight asst and the combined motor torque command value w2·T after multiplying by the second weight mint，cmd the sum is used to control the electric motor 18.

[0162] In the first control mode, the steering reaction force based on the imaginary road surface load torque T MD，cmd calculated based on the manual steering operation command value θ rl is not reflected.

[0163] If the process of step S5 is performed, the weight setting unit 52 returns to step S2.

[0164] In addition, 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. Therefore, in the normal mode, the electric motor 18 is driven and controlled only based on the auxiliary torque command value T asst .

[0165] Next, the operation of the road surface reaction force characteristic setting unit 43 will be described in detail. The road surface reaction force characteristic setting unit 43 sets the imaginary load spring stiffness coefficient k and the imaginary load viscous damping coefficient c for the calculation of the manual steering operation command value θ MD，cmd . In addition, the calculation of the manual steering operation command value θ MD，cmd is performed by the manual steering operation command value generation unit 45 (see Figure 2 ).

[0166] First, the operation of the road surface reaction force characteristic setting unit 43 when the driving mode is the driving assistance mode will be described.

[0167] In this embodiment, as the imaginary load spring stiffness coefficient k used in the driving assistance mode, two stiffness coefficients, the first imaginary load spring stiffness coefficient kr(e L ) and the second imaginary load spring stiffness coefficient kg, are prepared. On the other hand, as the imaginary load viscous damping coefficient c used in the driving assistance mode, only one imaginary load viscous damping coefficient c(e L ) is prepared.

[0168] Figure 10 is a graph showing setting examples of the first imaginary load spring stiffness coefficient kr(e L ) and the second imaginary load spring stiffness coefficient kg with respect to the lateral deviation e L .

[0169] The stiffness coefficient kr(e) of the first imaginary load spring L ) is set to a constant value k1 when the absolute value |e L | of the lateral deviation e L is equal to or less than the above-mentioned α. k1 is a specified value greater than 0. When the absolute value |e L | of the lateral deviation e L is greater than α, the stiffness coefficient kr(e L ) of the first imaginary load spring is set from k1 to k2 which is greater than k1, and the greater the absolute value |e L | of the lateral deviation e L , the greater the stiffness coefficient kr(e L ). In Figure 10 , although the stiffness coefficient kr(e L ) of the first imaginary load spring changes linearly from k1 to k2, it can also change non-linearly.

[0170] The stiffness coefficient kg of the second imaginary load spring is set to a constant value k3 regardless of the lateral deviation e L . k3 is set to a value greater than 0 and less than k1.

[0171] Figure 10 The values of the stiffness coefficient kr(e L ) of the first imaginary load spring with respect to the lateral deviation e L shown in are stored in the memory as the first spring stiffness coefficient mapping table. In addition, Figure 10 the value k3 of the stiffness coefficient kg of the second imaginary load spring shown in is stored in the memory as the stiffness coefficient kg of the second imaginary load spring.

[0172] Figure 11 is a graph showing an example of setting the viscous damping coefficient c(e L ) of the imaginary load with respect to the lateral deviation e L .

[0173] The viscous damping coefficient c(e L ) of the imaginary load is set to a constant value c1 when the absolute value |e L | of the lateral deviation e L is equal to or less than α. c1 is a specified value greater than 0. When the absolute value |e L | of the lateral deviation e L is greater than α, the viscous damping coefficient c(e L ) of the imaginary load is set from c1 to c2 which is greater than c1, and the greater the absolute value |e L | of the lateral deviation e L , the greater the viscous damping coefficient c(e L ). In Figure 11Among them, the imaginary load viscous attenuation coefficient c(e L ) changes linearly from c1 to c2, but it can also change non-linearly.

[0174] Figure 11 The imaginary load viscous attenuation coefficient c(e L ) with respect to the lateral deviation e L ) is stored in the memory as a viscous attenuation coefficient mapping table.

[0175] In this embodiment, the road surface reaction force characteristic setting unit 43, in the driving assistance mode, for example, based on the stored Figure 11 imaginary load viscous attenuation coefficient c(e L ) with respect to the lateral deviation e L ) value of the viscous attenuation coefficient mapping table and the lateral deviation e L from the upper ECU 201, sets the value of the imaginary load viscous attenuation coefficient c. In addition, the road surface reaction force characteristic setting unit 43, in the driving assistance mode, may also set a predetermined imaginary load viscous attenuation coefficient value (fixed value) as the imaginary load viscous attenuation coefficient c.

[0176] The road surface reaction force characteristic setting unit 43, in the driving assistance mode, performs a spring rigidity coefficient setting process for setting the imaginary load spring rigidity coefficient k. The spring rigidity coefficient setting process will be described later.

[0177] In the driving assistance mode, the state where the vehicle moves toward the lane boundary (the state where the driver has performed a steering operation in such a way that the vehicle moves toward the lane boundary) is referred to as "the state where the vehicle is toward the deviation side". On the other hand, the state where the vehicle moves toward the center of the lane (the state where the vehicle attempts to return to the center of the lane) is referred to as "the state where the vehicle is toward avoiding the deviation side".

[0178] The road surface reaction force characteristic setting unit 43 determines whether it is the state where the vehicle is toward the deviation side or the state where the vehicle is toward avoiding the deviation side based on the lateral deviation e L , the automatic steering operation command value θ AD，cmd and the actual steering operation angle θ. Specifically, it is determined based on the sign of the lateral deviation e L and the angular deviation Δθ AD，cmd between the actual steering operation angle θ and the automatic steering operation command value θ A (= θ - θ AD，cmd ) time differential value dΔθ A / dt.

[0179] When the sign of the lateral deviation e L is negative, that is, when the vehicle reference position is on the right side of the lane center, if the time differential value dΔθA If it is above the specified threshold β (where β > 0), the road surface reaction force characteristic setting unit 43 determines that the vehicle is in a state of turning towards the avoidance deviation side.

[0180] When the lateral deviation e L has a negative sign, if the time differential value dΔθ A / dt is not above β (where β > 0), that is, when the time differential value dΔθ A / dt is greater than -β and less than β and when the time differential value dΔθ A / dt is below -β, the road surface reaction force characteristic setting unit 43 determines that the vehicle is in a state of turning towards the deviation side.

[0181] The specified threshold β is set to prevent frequent switching between the state of the vehicle turning towards the avoidance deviation side and the state of the vehicle turning towards the deviation side within the range where the time differential value dΔθ A / dt is below the threshold β.

[0182] When the time differential value dΔθ A / dt is greater than -β and less than β, the reason why the road surface reaction force characteristic setting unit 43 determines that the vehicle is in a state of turning towards the deviation side is that when the vehicle reference position is near the center of the lane, even when the vehicle slightly turns towards the lane boundary side with the driver keeping the steering wheel in the neutral position, it is determined that the vehicle is in a state of turning towards the deviation side.

[0183] In addition, when the time differential value dΔθ A / dt is greater than -β and less than β, the road surface reaction force characteristic setting unit 43 may also determine that the vehicle is in a state of turning towards the avoidance deviation side.

[0184] Figure 12A , Figure 12B and Figure 12C represent the angle deviation Δθ AD，cmd between the automatic steering operation command value θ A and the actual steering operation angle θ when the vehicle reference position is on the right side of the center of the lane.

[0185] In Figure 12A , Figure 12B and Figure 12C , the steering wheel angle of the large steering wheel 301 schematically represents the actual steering operation angle θ, and the steering wheel angle of the small steering wheel 302 schematically represents the automatic steering operation command value θ AD，cmd .

[0186] Figure 12AIt is a schematic diagram showing an example of the position of the vehicle 300 when the vehicle reference position is located on the right side of 313 from the center of the lane. In addition, the reference numeral 311 denotes the white line of the left lane boundary, and the reference numeral 312 denotes the white line of the right lane boundary. In this case, the lateral deviation e L has a negative sign.

[0187] Figure 12B It is a schematic diagram showing an example of the actual steering angle θ, the automatic steering command value θ AD，cmd , and the angle deviation Δθ A (=θ - θ AD，cmd ). In the case where the actual steering angle θ and the automatic steering command value θ AD，cmd are in this relationship, for example, if the driver turns the steering wheel in the left steering direction (positive direction), the angle deviation Δθ A increases, and the time differential value dΔθ A / dt is positive.

[0188] On the other hand, in the case where the actual steering angle θ and the automatic steering command value θ AD，cmd are in this relationship, for example, if the driver turns the steering wheel in the right steering direction (negative direction), the angle deviation Δθ A decreases, and the time differential value dΔθ A / dt is negative.

[0189] Figure 12C It is a schematic diagram showing an example of the actual steering angle θ, the automatic steering command value θ AD，cmd , and the angle deviation Δθ A (=θ - θ AD，cmd ). In the case where the actual steering angle θ and the automatic steering command value θ AD，cmd are in this relationship, for example, if the driver turns the steering wheel in the left steering direction (positive direction), the angle deviation Δθ A increases (approaches 0), and the time differential value dΔθ A / dt is positive.

[0190] On the other hand, in the case where the actual steering angle θ and the automatic steering command value θ AD，cmd are in this relationship, for example, if the driver turns the steering wheel in the right steering direction (negative direction), the angle deviation Δθ A decreases (moves away from 0), and the time differential value dΔθ A / dt is negative.

[0191] When the sign of the lateral deviation e L is positive, that is, when the vehicle reference position is located on the left side of the center of the lane, if the time differential value dΔθA When / dt is less than or equal to -β, the road surface reaction force characteristic setting unit 43 determines that the vehicle is in a state of turning toward the avoidance deviation side.

[0192] When the sign of the lateral deviation e L is positive, if the time differential value dΔθ A / dt is not less than -β, that is, when the time differential value dΔθ A / dt is greater than -β and less than β, and when the time differential value dΔθ A / dt is greater than or equal to β, the road surface reaction force characteristic setting unit 43 determines that the vehicle is in a state of turning toward the deviation side.

[0193] When the time differential value dΔθ A / dt is greater than -β and less than β, the reason why the road surface reaction force characteristic setting unit 43 determines that the vehicle is in a state of turning toward the deviation side is as described above.

[0194] In addition, when the time differential value dΔθ A / dt is greater than -β and less than β, the road surface reaction force characteristic setting unit 43 may also determine that the vehicle is in a state of turning toward the avoidance deviation side.

[0195] Figure 13 is a flowchart showing the steps of the spring stiffness coefficient setting process performed by the road surface reaction force characteristic setting unit 43 in the driving assistance mode. Figure 13 The shown spring stiffness coefficient setting process starts each time the driving assistance mode is started and is repeatedly executed in units of a specified operation cycle until the driving assistance mode is canceled.

[0196] The road surface reaction force characteristic setting unit 43 first obtains the lateral deviation e provided from the upper ECU 201 L and the automatic steering operation command value θ AD，cmd and the actual steering operation angle θ calculated by the reduction ratio division unit 42 (step S11).

[0197] Next, the road surface reaction force characteristic setting unit 43 determines whether the lateral deviation e L is less than 0 (step S12). In other words, the road surface reaction force characteristic setting unit 43 determines whether the sign of the lateral deviation e L is negative.

[0198] When the lateral deviation e L is less than 0 (step S12: YES), the road surface reaction force characteristic setting unit 43 determines the angle deviation Δθ between the actual steering operation angle θ and the automatic steering operation command value θ AD，cmd (=θ - θ A (=θ - θAD，cmd ) time differential value dΔθ A / dt is β or more (step S13).

[0199] When the time differential value dΔθ A / dt is β or more (step S13: YES), the road surface reaction force characteristic setting unit 43 determines that the vehicle is in a state of turning toward the avoidance deviation side, and sets the second imaginary load spring rigidity coefficient kg as the imaginary load spring rigidity coefficient k (step S14). Then, the processing for this operation cycle is ended.

[0200] In step S13 described above, when it is determined that the time differential value dΔθ A / dt is less than β (step S13: NO), the road surface reaction force characteristic setting unit 43 determines that the vehicle is in a state of turning toward the deviation side, and sets the first imaginary load spring rigidity coefficient kr(e L ) as the imaginary load spring rigidity coefficient k (step S15).

[0201] Specifically, the road surface reaction force characteristic setting unit 43 is based on the storage of Figure 10 with respect to the lateral deviation e L the first imaginary load spring rigidity coefficient kr(e L ) value of the first spring rigidity coefficient mapping table and the lateral deviation e obtained in step S11 L , and the first imaginary load spring rigidity coefficient kr(e L ) value corresponding to the lateral deviation e L ) is set as the imaginary load spring rigidity coefficient k. Then, the processing for this operation cycle is ended.

[0202] In step S12 described above, when it is determined that the lateral deviation e L is 0 or more (step S12: NO), the road surface reaction force characteristic setting unit 43 determines whether the time differential value dΔθ A / dt is -β or less (step S16).

[0203] When the time differential value dΔθ A / dt is -β or less (step S16: YES), the road surface reaction force characteristic setting unit 43 determines that the vehicle is in a state of turning toward the avoidance deviation side, and sets the second imaginary load spring rigidity coefficient kg as the imaginary load spring rigidity coefficient k (step S17). Then, the processing for this operation cycle is ended.

[0204] In step S16 described above, when it is determined that the time differential value dΔθ AWhen the / dt ratio is greater than β (step S16: No), the road surface reaction force characteristic setting unit 43 determines that the vehicle is in a state of deviating toward the deviation side, and sets the first imaginary load spring stiffness coefficient kr(e L ) as the imaginary load spring stiffness coefficient k (step S18). Then, the processing of this operation cycle is ended.

[0205] In addition, in steps S14 and S17, in the previous operation cycle, when the first imaginary load spring stiffness coefficient kr(e L ) is set as the imaginary load spring stiffness coefficient k, it is preferable to decrease the imaginary load spring stiffness coefficient k from the previous value of the imaginary load spring stiffness coefficient k to the value of the second imaginary load spring stiffness coefficient kg.

[0206] Similarly, in steps S15 and S18, in the previous operation cycle, when the second imaginary load spring stiffness coefficient kg is set as the imaginary load spring stiffness coefficient k, it is preferable to increase the imaginary load spring stiffness coefficient k from the previous value of the imaginary load spring stiffness coefficient k to the value of the first imaginary load spring stiffness coefficient kr(e L ).

[0207] 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 the manual steering operation command value θ MD，cmd does not reflect the motor torque command value T m，cmd . In other words, the steering reaction force based on the manual steering operation command value θ MD，cmd is not reflected. However, in this embodiment, in the normal mode, the manual steering operation command value generation unit 45 causes the road surface reaction force characteristic setting unit 43 to set the imaginary load spring stiffness coefficient k and the imaginary load viscous damping coefficient c in order to be able to continue the operation of the manual steering operation command value θ MD，cmd .

[0208] Specifically, when the driving mode is the normal mode, the road surface reaction force characteristic setting unit 43 sets the imaginary load spring stiffness coefficient k to a preset specified value k M , and sets the imaginary load viscous damping coefficient c to a preset specified value c M . k M For example, it can also be set to Figure 10 k1. c M For example, it can also be set to Figure 11 c1.

[0209] In addition, in the normal mode, the operation of the manual steering operation command value generation unit 45 can also be stopped. In this case, the road surface reaction force characteristic setting unit 43 can also not set the imaginary load spring rigidity coefficient k and the imaginary load viscous damping coefficient c in the normal mode.

[0210] In the above structure, in the driving assistance mode, when it is determined that the vehicle is in a state of deviating toward the deviation side, the first imaginary load spring rigidity coefficient kr(e L ) is set as the imaginary load spring rigidity coefficient k. On the other hand, when it is determined that the vehicle is in a state of avoiding the deviation side, the second imaginary load spring rigidity coefficient kg is set as the imaginary load spring rigidity coefficient k.

[0211] Thereby, it is possible to set the imaginary load spring rigidity coefficient k that is respectively suitable for the state in which the vehicle is oriented toward the deviation side and the state in which the vehicle is oriented toward the avoidance of the deviation side. Thereby, it is possible to generate a steering reaction force that is respectively suitable for the state in which the vehicle is oriented toward the deviation side and the state in which the vehicle is oriented toward the avoidance of the deviation side. That is, in the first embodiment, in the driving assistance mode, it is possible to apply a steering reaction force to the driver by a new method.

[0212] Specifically, in the state where the vehicle is oriented toward the deviation side, since the greater the distance of the vehicle reference position from the center of the lane, the greater the steering reaction force, it is possible to effectively prevent the vehicle from deviating from the lane. In the state where the vehicle is oriented toward the avoidance of the deviation side, compared with the state where the vehicle is oriented toward the deviation side, the steering reaction force becomes smaller, so the stabilization of the vehicle behavior and the discomfort of the driver are reduced.

[0213] In addition, as Figure 10 shown, it is preferable that the second imaginary load spring rigidity coefficient kg is smaller than the first imaginary load spring rigidity coefficient kr(e L ).

[0214] However, in the first embodiment, when the distance of the vehicle reference position from the center of the lane is within α, the first weight W1 is set to 1 and the second weight W2 is set to 0, so the manual steering operation command value θ MD，cmd is not reflected in the motor torque command value T m，cmd . In other words, the steering reaction force based on the manual steering operation command value θ MD，cmd is not reflected. Even so, since the vehicle reference position is located at a position relatively close to the center of the lane, the vehicle does not deviate from the lane.

[0215] In the technology described in Patent Document 1, the control gain is changed based on the yaw angle of the vehicle with respect to the driving lane. Since the detection of the yaw angle is delayed with respect to the driver's operation, there is a problem that the timing of changing the control gain is delayed with respect to the driver's operation.

[0216] In contrast, in this first embodiment, based on the actual steering angle θ and the automatic steering command value θ AD，cmd angle deviation Δθ A (= θ - θ AD，cmd ), the time differential value dΔθ A / dt of is determined to be a state where the vehicle is oriented toward the deviation side or a state where the vehicle is oriented toward avoiding the deviation side, and the virtual load spring stiffness coefficient k is switched based on the determination result. The time differential value dΔθ A / dt is less likely to be delayed with respect to the driver's operation, so the virtual load spring stiffness coefficient k can be switched quickly with respect to the switching of the steering operation direction performed by the driver. As a result, the driver obtains an intuitive steering feeling.

[0217] [Explanation of the first modification of the road surface reaction force characteristic setting unit 43]

[0218] An explanation of the first modification of the road surface reaction force characteristic setting unit 43 will be given. In the above first embodiment, in the driving assistance mode, when it is determined that the vehicle is in a state of facing the deviation side and when it is determined that the vehicle is in a state of facing the side avoiding the deviation, the virtual load spring stiffness coefficient k is switched.

[0219] In the first modification of the road surface reaction force characteristic setting unit 43, in the driving assistance mode, when it is determined that the vehicle is in a state of facing the deviation side and when it is determined that the vehicle is in a state of facing the side avoiding the deviation, both the virtual load spring stiffness coefficient k and the virtual load viscous damping coefficient c are switched.

[0220] In this case, as the virtual load spring stiffness coefficient k, two stiffness coefficients, the first virtual load spring stiffness coefficient kr(e L ) and the second virtual load spring stiffness coefficient kg, are prepared, and as the virtual load viscous damping coefficient c, two damping coefficients, the first virtual load viscous damping coefficient cr(e L ) and the second virtual load viscous damping coefficient cg, are prepared.

[0221] Figure 14 is a graph showing a setting example of the first virtual load viscous damping coefficient cr(e L ) with respect to the lateral deviation e L ) and the second virtual load viscous damping coefficient cg.

[0222] The first hypothetical load viscous attenuation coefficient cr(e L ) when the lateral deviation e L has an absolute value |e L | less than or equal to α, is set to a constant value c1. c1 is a specified value greater than 0. When the absolute value of the lateral deviation e L |e L | is greater than α, the first hypothetical load viscous attenuation coefficient cr(e L ) is set to increase from c1 to c2 (where c2 is greater than c1) according to the characteristic that the greater the absolute value |e L | of the lateral deviation e L , the greater the first hypothetical load viscous attenuation coefficient cr(e L ). In Figure 14 , the first hypothetical load viscous attenuation coefficient cr(e L ) may vary non-linearly although it varies linearly from c1 to c2.

[0223] The second hypothetical load viscous attenuation coefficient cg is set to a constant value c3 regardless of the lateral deviation e L . c3 is set to a value greater than 0 and less than c1. As Figure 14 shown, it is preferable that the second hypothetical load viscous attenuation coefficient cg is less than the first hypothetical load viscous attenuation coefficient cr(e L ). However, as Figure 14 shown by the dotted line, for the purpose of mitigating the restoration of the steering operation reaction force, the second hypothetical load viscous attenuation coefficient cg may also be set to a value (c4) greater than c1.

[0224] Figure 14 The value of the first hypothetical load viscous attenuation coefficient cr(e L ) with respect to the lateral deviation e L as shown in Figure 14 is stored in the memory as a first viscous attenuation coefficient mapping table. Additionally,

[0225] Figure 15 is a flowchart showing the steps of the road surface reaction force characteristic setting process performed by the road surface reaction force characteristic setting unit 43 in the first modification example in the driving assistance mode. Figure 15 The road surface reaction force characteristic setting process shown in

[0226] starts each time the driving assistance mode is started and is repeatedly executed in units of a specified operation cycle until the driving assistance mode is canceled. Figure 15 In Figure 13 , steps corresponding to the respective steps of the above Figure 13Same step numbers.

[0227] The processing of steps S14A, S15A, S17A, and S18A is different from that of steps S14, S15, S17, and S18 of Figure 13 respectively. The processing of the other steps S11, S12, S13, and S16 is the same as that of steps S11, S12, S13, and S16 of Figure 13 respectively.

[0228] In steps S14A and S17A, the road surface reaction force characteristic setting unit 43 sets the second imaginary load spring stiffness coefficient kg to the imaginary load spring stiffness coefficient k, and sets the second imaginary load viscous damping coefficient cg to the imaginary load viscous damping coefficient c. Then, the processing of this operation cycle is ended.

[0229] In steps S15A and S18A, the road surface reaction force characteristic setting unit 43 sets the first imaginary load spring stiffness coefficient kr(e L ) to the imaginary load spring stiffness coefficient k and sets the first imaginary load viscous damping coefficient cr(e L ) to the imaginary load viscous damping coefficient c.

[0230] Specifically, the road surface reaction force characteristic setting unit 43 is based on the first spring stiffness coefficient mapping table storing the value of the first imaginary load spring stiffness coefficient kr with respect to the lateral deviation e Figure 10 and the lateral deviation e obtained in step S11 L . The value of the first imaginary load spring stiffness coefficient kr corresponding to the lateral deviation e L is set to the imaginary load spring stiffness coefficient k. L

[0231] In addition, the road surface reaction force characteristic setting unit 43 is based on the first viscous damping coefficient mapping table storing the value of the first imaginary load viscous damping coefficient cr(e Figure 14 ) with respect to the lateral deviation e L and the lateral deviation e obtained in step S11 L . The value of the first imaginary load viscous damping coefficient cr(e L ) corresponding to this lateral deviation e L is set to the imaginary load viscous damping coefficient c. L

[0232] The operation of the road surface reaction force characteristic setting unit 43 in the normal mode is the same as that in the first embodiment described above.

[0233] [Explanation of the second modification of the road surface reaction force characteristic setting unit 43]

[0234] A second modification example of the road surface reaction force characteristic setting unit 43 will be described. In the first modification example of the road surface reaction force characteristic setting unit 43 described above, in the driving assistance mode, when it is determined that the vehicle is in a state of facing the deviation side, and when it is determined that the vehicle is in a state of facing away from the deviation side, the imaginary load spring rigidity coefficient k and the imaginary load viscous damping coefficient c are switched.

[0235] In the second modification example of the road surface reaction force characteristic setting unit 43, in the driving assistance mode, when it is determined that the vehicle is in a state of facing the deviation side, and when it is determined that the vehicle is in a state of facing away from the deviation side, only the imaginary load viscous damping coefficient c is switched.

[0236] The road surface reaction force characteristic setting unit 43, in the driving assistance mode, for example, based on Figure 10 stored with respect to the lateral deviation e L of the first imaginary load spring rigidity coefficient kr(e L ) value of the viscous damping coefficient mapping table and the lateral deviation e from the upper ECU 201 L , sets the value of the imaginary load spring rigidity coefficient k. In addition, the road surface reaction force characteristic setting unit 43, in the driving assistance mode, may also set a predetermined specified imaginary load spring rigidity coefficient value (fixed value) as the imaginary load spring rigidity coefficient k.

[0237] As the imaginary load viscous damping coefficient c, for example, prepare Figure 14 shown in the first imaginary load viscous damping coefficient cr(e L ) and the second imaginary load viscous damping coefficient cg these two damping coefficients. Figure 14 shown with respect to the lateral deviation e L of the first imaginary load viscous damping coefficient cr(e L ) value as the first viscous damping coefficient mapping table is stored in the memory. In addition, Figure 14 shown in the second imaginary load viscous damping coefficient cg value c3 is stored in the memory.

[0238] The road surface reaction force characteristic setting unit 43, in the driving assistance mode, executes a viscous damping coefficient setting process for setting the imaginary load viscous damping coefficient c.

[0239] Figure 16 is a flowchart showing the steps of the viscous damping coefficient setting process performed by the road surface reaction force characteristic setting unit 43 in the driving assistance mode. Figure 16 The viscous damping coefficient setting process shown starts each time the driving assistance mode is started, and is repeatedly executed in units of a specified operation cycle before the driving assistance mode is released.

[0240] InFigure 16 In this case, step numbers are marked for the steps corresponding to the above Figure 13 steps and the same step numbers are used to represent them as Figure 13 those in

[0241] The processing of steps S14B, S15B, S17B, and S18B is different from that of steps S14, S15, S17, and S18 in Figure 13 respectively. The processing of the other steps S11, S12, S13, and S16 is the same as that of steps S11, S12, S13, and S16 in Figure 13 respectively.

[0242] In steps S14B and S17B, the road surface reaction force characteristic setting unit 43 sets the second imaginary load viscous damping coefficient cg to the imaginary load viscous damping coefficient c. Then, the processing of this operation cycle is ended.

[0243] In steps S15B and S18B, the road surface reaction force characteristic setting unit 43 sets the first imaginary load viscous damping coefficient cr(e L ) to the imaginary load viscous damping coefficient c.

[0244] Specifically, the road surface reaction force characteristic setting unit 43, based on Figure 14 the spring rigidity coefficient mapping table of the first imaginary load viscous damping coefficient cr(e L ) with respect to the lateral deviation e L in L and the lateral deviation e L obtained in step S11, sets the value of the first imaginary load viscous damping coefficient cr(e L ) corresponding to this lateral deviation e

[0245] The operation of the road surface reaction force characteristic setting unit 43 in the normal mode is the same as that in the above first embodiment.

[0246] [Explanation of the modified example of the weight setting unit 52]

[0247] An explanation of the modified example of the weight setting unit 52 is given. In the above first embodiment ( Figure 2 and Figure 9 ), the weight setting unit 52 sets the first weight W1 and the second weight W2 based on the mode signal S mode and the lateral deviation e L . The weight setting unit 52 in the modified example sets the first weight W1 and the second weight W2 only based on the mode signal S mode .

[0248] 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. Other aspects are the same as those in the first embodiment above. That is, the operation of the road surface reaction force characteristic setting unit 43 is the same as the operation Figure 13 shown above.

[0249] Therefore, even in this modification, similar to the first embodiment above, when in the driving assistance mode, if it is determined that the vehicle is in a state of deviating towards the deviation side, the first imaginary load spring stiffness coefficient kr(e L ) is set to the imaginary load spring stiffness coefficient k. On the other hand, if it is determined that the vehicle is in a state of avoiding the deviation side, the second imaginary load spring stiffness coefficient kg is set to the imaginary load spring stiffness coefficient k.

[0250] In this modification, different from the first embodiment above, when in the driving assistance mode, even if the vehicle reference position is within α from the center of the lane, the first weight W1 is set to 0 and the second weight W2 is set to 1. Therefore, when in the driving assistance mode, even if the vehicle reference position is within α from the center of the lane, the steering reaction force based on the manual steering operation command value θ MD，cmd will be reflected.

[0251] Even when the road surface reaction force characteristic setting unit 43 in the first modification above is used as the road surface reaction force characteristic setting unit 43 (refer to Figure 15 ) or when the road surface reaction force characteristic setting unit 43 in the second modification above is used as the road surface reaction force characteristic setting unit 43 (refer to Figure 16 ), the weight setting unit 52 of the modification can be used as the weight setting unit 52.

[0252] [Description of the Second Embodiment]

[0253] In the second embodiment, the operations of the weight setting unit 52 and the road surface reaction force characteristic setting unit 43 are different from those in the first embodiment above.

[0254] In the second embodiment, similar to the modification of the weight setting unit 52 above, 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.

[0255] In addition, in the second embodiment, the road surface reaction force characteristic setting unit 43 obtains the lateral deviation e provided from the upper ECU 201 in units of a prescribed operation cycle in the driving assistance mode. L and the automatic steering operation command value θ AD，cmd and the actual steering operation angle θ calculated by the reduction ratio division unit 42. Next, the road surface reaction force characteristic setting unit 43 determines whether the lateral deviation e L is within the range of -α to +α. Moreover, the road surface reaction force characteristic setting unit 43 performs processing corresponding to the determination result. In other words, in the second embodiment, different operations are performed when the lateral deviation e L is within the range of -α to +α and when the lateral deviation e L is outside the range of -α to +α.

[0256] Specifically, when it is determined that the lateral deviation e L is outside the range of -α to +α, the road surface reaction force characteristic setting unit 43 performs the processing after step S12 of the above-described Figure 13 first embodiment. As the imaginary load viscous damping coefficient c used at this time, the imaginary load viscous damping coefficient c(e Figure 11 ) shown in L may be used, or a preset prescribed value (fixed value) may be used.

[0257] On the other hand, when it is determined that the lateral deviation e L is within the range of -α to +α, the road surface reaction force characteristic setting unit 43 does not determine whether the vehicle is in a state of avoiding the deviation side or a state of approaching the deviation side, but sets the imaginary load spring stiffness coefficient k to a preset prescribed value (for example, Figure 10 k1), and sets the imaginary load viscous damping coefficient c to a preset prescribed value (for example, Figure 11 c1).

[0258] The road surface reaction force characteristic setting unit 43 may also perform the following operation according to the determination result of whether the lateral deviation e L is within the range of -α to +α in the driving assistance mode. That is, when it is determined that the lateral deviation e L is outside the range of -α to +α, the road surface reaction force characteristic setting unit 43 performs the processing after step S12 of the above-described Figure 15 . On the other hand, when it is determined that the lateral deviation e L is within the range of -α to +α, the road surface reaction force characteristic setting unit 43 sets the imaginary load spring stiffness coefficient k and the imaginary load viscous damping coefficient c to preset prescribed values, respectively.

[0259] In addition, the road surface reaction force characteristic setting unit 43 may also, in the driving assistance mode, according to the lateral deviation e L Whether the discrimination result is within the range of -α to +α, perform the following actions. That is, when it is determined that the lateral deviation e L is outside the range of -α to +α, the road surface reaction force characteristic setting unit 43 performs the processing after the above-mentioned Figure 16 Step S12. On the other hand, when it is determined that the lateral deviation e L is within the range of -α to +α, the road surface reaction force characteristic setting unit 43 sets the imaginary load spring stiffness coefficient k and the imaginary load viscous damping coefficient c to predetermined specified values respectively.

[0260] In this second embodiment, when the lateral deviation e L is outside the range of -α to +α, lane keeping assistance (LKA) is performed. When the lateral deviation e L is within the range of -α to +α, lane centering assistance (LCA) control is performed.

[0261] [Description of the Third Embodiment]

[0262] In the third embodiment, the operations of the weight setting unit 52 and the road surface reaction force characteristic setting unit 43 are different from those of the above-mentioned first embodiment.

[0263] In the third embodiment, similar to the modification example of the above-mentioned weight setting unit 52, 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.

[0264] In addition, in the third embodiment, the road surface reaction force characteristic setting unit 43 performs different operations when the lateral deviation e L is within the range of -α to +α, and when the lateral deviation e L is outside the range of -α to +α.

[0265] Specifically, in the third embodiment, the road surface reaction force characteristic setting unit 43 performs the road surface reaction force characteristic setting process shown in Figure 17 in the driving assistance mode. In Figure 17 , the same steps as those in Figure 13 are labeled and shown with the same step numbers as those in Figure 13 the same steps. Figure 17The road surface reaction force characteristic setting process shown starts each time the driving assistance mode is started and is repeatedly executed in units of a specified operation cycle until the driving assistance mode is canceled.

[0266] The road surface reaction force characteristic setting unit 43 first obtains the lateral deviation e provided from the upper ECU 201 L and the automatic steering operation command value θ AD，cmd and the actual steering operation angle θ calculated by the reduction ratio division unit 42 (step S11).

[0267] Next, the road surface reaction force characteristic setting unit 43 determines whether the lateral deviation e L is within the range of -α ≤ e L ≤ +α (step S21). In other words, the road surface reaction force characteristic setting unit 43 determines whether the lateral deviation e L is within the range of -α to +α.

[0268] When it is determined that the lateral deviation e L is outside the range of -α ≤ e L ≤ +α (step S21: No), the road surface reaction force characteristic setting unit 43 moves to step S12. Specifically, the road surface reaction force characteristic setting unit 43 determines whether the lateral deviation e L is less than 0. The processes of steps S12 to S18 are the same as those of Figure 13 steps S12 to S18, so their detailed descriptions are omitted.

[0269] In step S21, when it is determined that the lateral deviation e L is within the range of -α ≤ e L ≤ +α (step S21: Yes), the road surface reaction force characteristic setting unit 43 determines the angular deviation Δθ AD，cmd between the actual steering operation angle θ and the automatic steering operation command value θ A (= θ - θ AD，cmd ) and determines whether it is less than 0 (step S22). In other words, the road surface reaction force characteristic setting unit 43 determines whether the sign of the angular deviation Δθ A is negative.

[0270] When the angular deviation Δθ A is less than 0 (step S22: Yes), the road surface reaction force characteristic setting unit 43 moves to step S13.

[0271] On the other hand, when the angular deviation Δθ A is 0 or more (step S22: No), the road surface reaction force characteristic setting unit 43 moves to step S16.

[0272] In Figure 17Among them, when the lateral deviation e is identified as L -α ≤ e L ≤ +α, and it is outside this range, the same processing as that shown in Figure 13 is performed. In this case, based on the lateral deviation e L and the angular deviation Δθ A (= θ - θ AD，cmd ), the time differential value dΔθ A / dt is used to determine whether the vehicle is in a state of deviating towards the deviation side or a state of deviating towards the side avoiding the deviation.

[0273] However, when the lateral deviation e is identified as L -α ≤ e L ≤ +α, and it is within this range, it is determined whether the angular deviation Δθ A (= θ - θ AD，cmd ) is less than 0. In this regard, Figure 17 the processing is different from that shown in Figure 13 . In this case, based on the angular deviation Δθ A (= θ - θ AD，cmd ) and its time differential value dΔθ A / dt, it is determined whether the vehicle is in a state of deviating towards the deviation side or a state of deviating towards the side avoiding the deviation.

[0274] Regarding the difference in processing when the identified lateral deviation e L is -α ≤ e L ≤ +α and it is outside this range and when the identified lateral deviation e L is -α ≤ e L ≤ +α and it is within this range, Figure 12B and Figure 12C are specifically described.

[0275] The relationship where the actual steering angle θ and the automatic steering command value θ AD，cmd are in Figure 12C (the vehicle is on the right side of the center of the lane and θ - θ AD，cmd < 0), and the lateral deviation e L is -α ≤ e L ≤ +α is defined as the first state. In the first state, for example, if the driver turns the steering wheel to the left steering direction (positive direction), the angular deviation Δθ A increases, and the time differential value dΔθ A / dt is positive. In this case, in Figure 17 step S21 of AWhen it exceeds the threshold value β, it becomes YES in step S13. Thus, it is determined that the vehicle is in a state of turning towards the avoidance deviation side, and the second imaginary load spring rigidity coefficient kg is set to the imaginary load spring rigidity coefficient k. That is, it becomes the same result as the processing in the case outside the range where L -α ≤ e L ≤ +α ( Figure 13 processing).

[0276] In the first state, for example, if the driver turns the steering wheel to the right steering operation direction (negative direction), the angle deviation Δθ A becomes smaller, and the time differential value dΔθ A / dt is negative. In this case, in Figure 17 step S21, it becomes YES, in step S22, it becomes YES, and in step S13, it becomes NO. Thus, it is determined that the vehicle is in a state of turning towards the deviation side, and the first imaginary load spring rigidity coefficient kr (e L ) is set to the imaginary load spring rigidity coefficient k. That is, it becomes the same result as the processing in the case outside the range where L -α ≤ e L ≤ +α ( Figure 13 processing).

[0277] The state where the actual steering angle θ and the automatic steering command value θ AD，cmd are in the Figure 12B relationship (the vehicle is on the right side of the center of the lane, and the relationship is θ - θ AD，cmd ≥ 0), and the lateral deviation e L is within the range of -α ≤ e L ≤ +α is called the second state. In the second state, for example, if the driver turns the steering wheel to the left steering operation direction (positive direction), the angle deviation Δθ A becomes larger, and the time differential value dΔθ A / dt is positive. In this case, in Figure 17 step S21, it becomes YES, in step S22, it becomes NO, and in step S16, it becomes NO. Thus, it is determined that the vehicle is in a state of turning towards the deviation side, and the first imaginary load spring rigidity coefficient kr (e L ) is set to the imaginary load spring rigidity coefficient k.

[0278] In this case, it becomes a result different from the processing in the case where the identified lateral deviation e L is within the range of -α ≤ e L ≤ +α ( Figure 13 processing). That is, when the lateral deviation e LWhen it is within the range of -α to +α, when the driver gives a further steering operation angle θ that exceeds the automatic steering operation command value θ AD，cmd such as the actual steering operation angle θ, it is determined that the vehicle is in a state of deviating toward the deviation side. In other words, when the possibility that the driver oversteers and exceeds the center of the lane becomes high, it is determined that the vehicle is in a state of deviating toward the deviation side

[0279] In the second state, for example, if the driver turns the steering wheel in the right steering operation direction (negative direction), the angle deviation Δθ A becomes smaller, and the time differential value dΔθ A / dt is negative. In this case, in Figure 17 step S21, it becomes yes, in step S22, it becomes no, and when the time differential value dΔθ A / dt is lower than the threshold value -β, it becomes yes in step S16. Thus, it is determined that the vehicle is in a state of avoiding the deviation side, and the second imaginary load spring stiffness coefficient kg is set to the imaginary load spring stiffness coefficient k. In this case, it becomes different from the processing in the case where the lateral deviation e L is outside the range of -α ≤ e L ≤ +α ( Figure 13 processing).

[0280] The road surface reaction force characteristic setting unit 43 may also replace Figure 17 each of the processes in steps S14, S15, S17, and S18, and perform Figure 15 the processes in steps S14A, S15A, S17A, and S18A of

[0281] In addition, the road surface reaction force characteristic setting unit 43 may also replace Figure 17 each of the processes in steps S14, S15, S17, and S18, and perform Figure 16 the processes in steps S14B, S15B, S17B, and S18B of

[0282] [Description of the Fourth Embodiment]

[0283] In the fourth embodiment, the operations of the weight setting unit 52 and the road surface reaction force characteristic setting unit 43 are different from those in the first embodiment above.

[0284] In the fourth embodiment, similar to the modification example of the weight setting unit 52 described above, 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.

[0285] In the fourth embodiment, the road surface reaction force characteristic setting unit 43 performs the road surface reaction force characteristic setting process shown in Figure 18 when in the driving assistance mode. In Figure 18 , the same steps as those in Figure 13 are labeled and represented with the same step numbers as those in Figure 13 . Figure 18 The road surface reaction force characteristic setting process shown starts each time the driving assistance mode is started and is repeatedly executed in units of a prescribed operation cycle until the driving assistance mode is canceled.

[0286] Figure 18 Step S12A in Figure 13 is different from step S12 in Figure 18 . That is, in the road surface reaction force characteristic setting process in AD，cmd , in step S12A, the road surface reaction force characteristic setting unit 43 discriminates the angular deviation Δθ A (=θ - θ AD，cmd ) between the actual steering operation angle θ and the automatic steering operation command value θ A to see if it is less than 0. Moreover, when it is determined that the angular deviation Δθ A is less than 0, the road surface reaction force characteristic setting unit 43 proceeds to step S13, and when it is determined that the angular deviation Δθ Figure 13 is 0 or more, the road surface reaction force characteristic setting unit 43 proceeds to step S16.

[0287] In addition, as the imaginary load viscous damping coefficient c used in the driving assistance mode, the imaginary load viscous damping coefficient c(e Figure 11 ) shown in L can be used, or a preset prescribed value (fixed value) can also be used.

[0288] In addition, the road surface reaction force characteristic setting unit 43 can perform the processes of steps S14A, S15A, S17A, and S18 in Figure 18 instead of the respective processes of steps S14, S15, S17, and S18. Figure 15

[0289] Furthermore, the road surface reaction force characteristic setting unit 43 can perform the processes of steps S14B, S15B, S17B, and S18 in Figure 18 instead of the respective processes of steps S14, S15, S17, and S18. Figure 16

[0290] [Description of a modification example of the motor control ECU]

[0291] Figure 19 It is a block diagram showing a first modification example of an ECU for motor control. In Figure 19 , the parts corresponding to the respective parts of the above Figure 2 are labeled and shown with the same reference numerals as Figure 2 .

[0292] In Figure 19 the motor control ECU 202A, in the following (1) and (2), it is different from Figure 2 the motor control ECU 202.

[0293] (1) Instead of Figure 2 the road surface reaction force characteristic setting unit 43, a motion equation setting unit 43A is provided.

[0294] (2) The structure of the manual steering operation command value generation unit 45A is different from that of Figure 2 the manual steering operation command value generation unit 45.

[0295] The motion equation setting unit 43A sets the target imaginary spring reaction force T L based on the lateral deviation e tb，d provided from the upper ECU 201 L . In addition, the motion equation setting unit 43A sets the imaginary load spring stiffness coefficient k md and the imaginary load viscous damping coefficient c md used by the manual steering operation command value generation unit 45A. In addition, the motion equation setting unit 43A sets the third to sixth weights W3 to W6 used by the manual steering operation command value generation unit 45A. The motion equation setting unit 43A performs the coefficient / weight setting process described later in the driving assistance mode.

[0296] In addition, 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 normal mode. 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.

[0297] Therefore, when the driving mode is the normal mode, the auxiliary torque T asst set by the auxiliary torque command value setting unit 44 is provided to the torque control unit 51 as the motor torque command value T m，cmd . On the other hand, when the driving mode is the driving assistance mode, the combined motor torque command value T mint，cmd calculated by the angle control unit 47 is provided to the torque control unit 51 as the motor torque command value T m，cmd .

[0298] Figure 20 represents the target imaginary spring reaction force T L with respect to the lateral deviation e tb，d (e L ). The diagram shows an example of the setting.

[0299] For the lateral deviation e L ranging from -e L，S (where e L，S > 0) to e L，S , the target imaginary spring reaction force T tb，d (e L ) ranges from -T tb，d，S (where T tb，d，S > 0) to T tb，d，S , and is set to be larger as the lateral deviation e L becomes larger. In this example, the target imaginary spring reaction force T tb，d (e L ) varies linearly, but it can also vary non-linearly. In this example, e L，S is set to a specified value greater than zero and less than half of the driving lane width.

[0300] For the lateral deviation e L ranging from e L，S to e L，m (where e L，m > e L，S ), the target imaginary spring reaction force T tb，d (e L ) ranges from T tb，d，S to T tb，d，m (where T tb，d，m > T tb，d，S ), and is set to be larger as the lateral deviation e L becomes larger. For the lateral deviation e L ranging from e L，S to e L，m , compared with the range where the lateral deviation e L ranges from -e L，S to e L，S , the slope of the straight line representing the target imaginary spring reaction force T tb，d (e L ) is set to be larger. In this example, the target imaginary spring reaction force T tb，d (e L ) varies linearly, but it can also vary non-linearly. In the range where the lateral deviation e L is larger than e L，m , the target imaginary spring reaction force T tb，d (e L ) is set to T tb，d，m .

[0301] In the lateral deviation e L from -e L，S to -e L，m (where -e L，m <-e L，S ), the target imaginary spring reaction force T tb，d (e L ), from -T tb，d，S to -T tb，d，m (where -T tb，d，m <-T tb，d，S ), the lateral deviation e L is set to be smaller as it gets smaller. In the range where the lateral deviation e L is from -e L，S to -e L，m , compared with the range where the lateral deviation e L is from -e L，S to e L，S , the slope of the straight line representing the target imaginary spring reaction force T tb，d (e L ) is set to be larger. In this example, although the target imaginary spring reaction force T tb，d (e L ) changes linearly, it can also change non-linearly. In the range where the lateral deviation e L is less than -e L，m , the target imaginary spring reaction force T tb，d (e L ) is set to -T tb，d，m .

[0302] The target imaginary spring reaction force T tb，d (e L ) set by the motion equation setting unit 43A is provided to the manual steering operation command value generation unit 45A.

[0303] In this modification example, as the imaginary load spring stiffness coefficient k md used in the driving assistance mode, two stiffness coefficients, the first imaginary load spring stiffness coefficient kr and the second imaginary load spring stiffness coefficient kg, are prepared.

[0304] Figure 21 is a graph showing setting examples of the first imaginary load spring stiffness coefficient kr and the second imaginary load spring stiffness coefficient kg with respect to the lateral deviation e L .

[0305] The first imaginary load spring stiffness coefficient kr is only set when the absolute value |e L | of the lateral deviation e L is Figure 20 eL，S The following ranges. The first imaginary load spring stiffness coefficient kr is set to a constant value k1 regardless of the lateral deviation e. L The second imaginary load spring stiffness coefficient kg is set to a constant value k3 regardless of the lateral deviation e. L k3 is set to a value greater than 0 and less than k1. Figure 21 The value k1 of the first imaginary load spring stiffness coefficient kr and the value k3 of the second imaginary load spring stiffness coefficient kg shown in FIG. are stored in the memory.

[0306] In this modification example, as the imaginary load viscous damping coefficient c used in the driving assistance mode, md two types of damping coefficients, the first imaginary load viscous damping coefficient cr(e L ) and the second imaginary load viscous damping coefficient cg, are prepared.

[0307] Figure 22 is a graph showing a setting example of the first imaginary load viscous damping coefficient cr(e L ) with respect to the lateral deviation e L ) and the second imaginary load viscous damping coefficient cg.

[0308] The first imaginary load viscous damping coefficient c(e L ) is set to a constant value c1 when the absolute value |e L | of the lateral deviation e L | is e L，S or less. c1 is a specified value greater than 0. When the absolute value |e L | of the lateral deviation e L | is greater than e L，S , the first imaginary load viscous damping coefficient c(e L ) is set from c1 to c2 which is greater than c1 according to the characteristic that the larger the absolute value |e L | of the lateral deviation e L , the larger the first imaginary load viscous damping coefficient c(e L ). In Figure 22 , the first imaginary load viscous damping coefficient c(e L ) changes linearly from c1 to c2, but may also change non-linearly.

[0309] The second imaginary load viscous damping coefficient cg is set to a constant value c3 regardless of the lateral deviation e L . c3 is set to a value greater than 0 and less than c1.

[0310] Figure 22 The first imaginary load viscous damping coefficient c(e L ) with respect to the lateral deviation e shown in FIG.L ) The value is stored in the memory as a viscous damping coefficient mapping table. Additionally, Figure 22 The value c3 of the viscous damping coefficient cg of the second imaginary load shown is stored in the memory.

[0311] The manual steering operation command value generation unit 45A will be described.

[0312] First, the manual steering operation command value θ generated by the manual steering operation command value generation unit (hereinafter referred to as the (comparative example manual steering operation command value generation unit)) described in Patent Document 2 (International Publication No. 2023 / 286169). MD，cmd The setting method will be described.

[0313] The comparative example manual steering operation command value generation unit uses Figure 23 the reference EPS model to generate the manual steering operation command value θ MD，cmd . Figure 23 The reference EPS model is an example of the "reference model of the steering operation device" of the present invention.

[0314] This reference EPS model is a single inertia model including the lower column. The lower column corresponds to the output shaft 9 and the worm wheel 21. However, this model is an example, and it can also be an inertia model including structures other than the above (for example, a rack, etc.). In Figure 23 , J md is the inertia of the lower column (hereinafter referred to as "column inertia"), θ col is the rotation angle of the lower column, and T tb is the torsion bar torque. The torsion bar torque T is applied to the lower column tb , the torque N·T acting on the output shaft 9 from the electric motor 18 m and the road surface reaction force torque (imaginary reaction force) T rl .

[0315] The road surface reaction force torque T rl uses the stiffness coefficient of the imaginary spring, that is, the imaginary load spring stiffness coefficient k md and the viscous damping coefficient of the imaginary shock absorber, that is, the imaginary load viscous damping coefficient c md , and is represented by the following formula (10).

[0316] [Mathematical formula 8]

[0317]

[0318] The imaginary load spring stiffness coefficient k md and the imaginary load viscous damping coefficient c md are obtained through preliminary experiments, analysis, etc. Hereinafter, k md·θ col is called the imaginary spring reaction force, c md (dθ col / dt) is called the imaginary shock absorber reaction force.

[0319] The motion equation of the reference EPS model is expressed by the following equation (11).

[0320] [Mathematical formula 9]

[0321]

[0322] In formula (11), J md ·d 2 θ col / dt 2 is the moment of inertia acting on the lower column.

[0323] The manual steering command value generating unit of the comparative example generates the torsion bar torque T detected by the torque sensor 12. tb Substitute T tb The assist torque command value T set by the assist torque command value setting unit 44 is asst Substitute T m , and solve the differential equation of formula (11) to calculate the rotation angle θ of the lower column col The manual steering command value generating unit of the comparative example sets the manual steering command value θ as MD，cmd The resulting rotation angle θ of the lower column col In this way, the manual steering command value θ is set MD，cmd The method is called the comparison method.

[0324] The equation of motion of formula (11) is equivalent to replacing T m Replace with T asst And θ col Replace with θ MD，cmd equation of motion.

[0325] In the comparison method, the spring stiffness coefficient k for the imaginary load is used as the imaginary spring reaction force. md Multiply the following column J md The rotation angle θ col (Manual steering command value θ MD，cmd ) is obtained. Therefore, as the virtual load spring stiffness coefficient k md Even if a value corresponding to the lateral position of the vehicle reference position is used, it is not possible to set a torque corresponding to the lateral position of the vehicle reference position as the virtual spring reaction force. Therefore, in the comparison method, in the coordinated control mode, the virtual spring reaction force k md ·θ col (=kmd ·θ MD，cmd ) becomes a reaction force that is left to develop.

[0326] In this modification, the manual steering operation command value generation unit 45A uses the equation of motion of the above reference EPS model (Equation (11)) to calculate the manual steering operation command value θ MD，cmd . Specifically, in this modification, the manual steering operation command value generation unit 45A uses the equation of motion obtained by deforming the equation of motion of the above reference EPS model (Equation (11)) to calculate the manual steering operation command value θ MD，cmd .

[0327] Figure 24 is a block diagram showing the structure of the manual steering operation command value generation unit 45A.

[0328] In Figure 24 , J md is the inertia of the column. s is the differential operator. θ MD，cmd is the manual steering operation command value, which corresponds to the rotation angle θ of the lower column in the comparison method col . md is the imaginary load spring stiffness coefficient, which is set by the equation of motion setting unit 43A. c md is the imaginary load viscous damping coefficient, which is set by the equation of motion setting unit 43A. T asst is the assist torque command value set by the assist torque command value setting unit 44.

[0329] The manual steering operation 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, an imaginary shock absorber reaction force calculation unit 405, a first imaginary spring reaction force calculation unit 406, a third weight multiplication unit 407, a second imaginary 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.

[0330] The reduction ratio multiplication unit 431 multiplies the assist torque command value T asst by the reduction ratio N of the speed reducer 19 to convert the assist torque command value T asst with respect to the rotation shaft of the electric motor 18 into the assist torque command value N·T asst with respect to the output shaft 9. The assist torque command value N·T asst calculated by the reduction ratio multiplication unit 431 is supplied to the addition / subtraction unit 401 and is also supplied to the first addition unit 410.

[0331] The torsion bar torque T is supplied to the addition / subtraction unit 401tb The auxiliary torque command value N·T with respect to the output shaft 9 calculated by the reduction ratio multiplication unit 431 asst The virtual shock absorber reaction force c provided by the virtual shock absorber reaction force calculation unit 405 md ·dθ MD，cmd / dt, and the addition result X of the third addition unit 414

[0332] The addition and subtraction unit 401 adds the torsion bar torque T tb to the auxiliary torque command value N·T with respect to the output shaft 9 asst , and subtracts the virtual shock absorber reaction force θ md ·dθ MD，cmd / dt and X from the addition result. Thus, the addition and subtraction unit 401 calculates J equivalent to the left side of the above formula (11) md ·d 2 θ col / dt 2 The moment of inertia J md ·d 2 θ MD，cmd / dt 2 (=T tb +N·T asst -c md ·dθ MD，cmd / dt-X).

[0333] The inertia division unit 402 divides the moment of inertia J md ·d 2 θ MD，cmd / dt 2 calculated by the addition and subtraction unit 401 by the column inertia J md to calculate the second derivative value d MD，cmd θ 2 of the manual steering operation command value θ MD，cmd / dt 2 .

[0334] The first integration unit 403 integrates the second derivative value d MD，cmd θ 2 of the manual steering operation command value θ MD，cmd / dt 2 to calculate the first derivative value dθ MD，cmd / dt of the manual steering operation command value θ MD，cmd .

[0335] The second integration unit 404 integrates the first derivative value dθ MD，cmd / dt of the manual steering operation command value θ MD，cmd to calculate the manual steering operation command value θ MD，cmd . This manual steering operation command value θMD，cmd is output from the manual steering operation command value generation unit 45A.

[0336] The virtual shock absorber reaction force calculation unit 405 calculates the virtual shock absorber reaction force c·dθ / dt by multiplying the first derivative dθ / dt of the manual steering operation command value θ calculated by the first integration unit 403 by the virtual load viscous damping coefficient c. This virtual shock absorber reaction force c·dθ / dt is fed back to the addition / subtraction unit 401. MD，cmd of the manual steering operation command value θ MD，cmd by the virtual load viscous damping coefficient c md to calculate the virtual shock absorber reaction force c md ·dθ MD，cmd / dt. This virtual shock absorber reaction force c md ·dθ MD，cmd / dt is fed back to the addition / subtraction unit 401.

[0337] The first virtual spring reaction force calculation unit 406 calculates the first virtual spring reaction force k·θ by multiplying the manual steering operation command value θ calculated by the second integration unit 404 by the virtual load spring stiffness coefficient k. MD，cmd by the virtual load spring stiffness coefficient k md to calculate the first virtual spring reaction force k md ·θ MD，cmd .

[0338] The third weight multiplication unit 407 multiplies the first virtual spring reaction force k md ·θ MD，cmd by the third weight W3.

[0339] The second virtual spring reaction force calculation unit 408 calculates the second virtual spring reaction force k·θ by multiplying the manual steering operation command value θ calculated by the second integration unit 404 by the virtual load spring stiffness coefficient k. MD，cmd by the virtual load spring stiffness coefficient k md to calculate the second virtual spring reaction force k md ·θ MD，cmd .

[0340] The fifth weight multiplication unit 409 multiplies the second virtual spring reaction force k md ·θ MD，cmd by the fifth weight W5.

[0341] The first addition unit 410 adds the target virtual spring reaction force T (e) to the auxiliary torque command value N·T with respect to the output shaft 9 calculated by the reduction ratio multiplication unit 431. The sixth weight multiplication unit 411 multiplies the operation result (T (e)) + N·T of the first addition unit 410 by the sixth weight W6. tb，d (e L ) to the auxiliary torque command value N·T with respect to the output shaft 9 calculated by the reduction ratio multiplication unit 431. The sixth weight multiplication unit 411 multiplies the operation result (T asst ) of the first addition unit 410 by the sixth weight W6. tb，d (e L ) + N·T asst ) by the sixth weight W6.

[0342] The second addition unit 412 adds the operation result W5·k of the fifth weight multiplication unit 409md ·θ MD，cmd and the operation result W6·(T tb，d (e L ) + N·T asst ) are added together.

[0343] The fourth weight multiplication unit 413 multiplies the operation result {W5·k md ·θ MD，cmd + W6·(T tb，d (e L ) + N·T asst )} of the second addition unit 412 by the fourth weight W4.

[0344] The third addition unit 414 adds the operation result W3·k md ·θ MD，cmd of the third weight multiplication unit 407 and the operation result W4·{W5·k md ·θ MD，cmd + W6·(T tb，d (e L ) + N·T asst )} of the fourth weight multiplication unit 413. The addition result [{W3·k md ·θ MD，cmd}+ W4·{W5·k md ·θ MD，cmd + W6·(T tb，d (e L ) + N·T asst )}] of the third addition unit 414 is fed back to the addition and subtraction unit 401 as X.

[0345] In this modified example, as will be described later, when the vehicle is in a state of facing away from the deviation side (non - deviation side), the third weight W3 is set to 1 and the fourth weight W4 is set to 0. On the other hand, when the vehicle is in a state of facing the deviation side, the third weight W3 is set to 0 and the fourth weight W4 is set to 1.

[0346] In addition, when the vehicle is in a state of facing the deviation side, when the lateral deviation e L is greater than -e L，S and less than e L，S , the driving assistance mode becomes the lane centering assistance mode (LCA mode), the fifth weight W5 is set to 1, and the sixth weight W6 is set to 0.

[0347] On the other hand, when the vehicle is in a state of facing the deviation side, when the lateral deviation e L is -e L，S or less, or e L，SIn the above case, the driving assistance mode becomes the lane keeping assistance mode (LKA mode), the fifth weight W5 is set to zero, and the sixth weight W6 is set to 1.

[0348] When the vehicle is in a state of facing away from the deviation side (non-deviation side), the addition result X of the third adder 414 becomes k md ·θ MD，cmd . Therefore, the operation result of the addition and subtraction unit 401 becomes (T tb +N·T asst -c md ·dθ MD，cmd / dt-k md ·θ MD，cmd ). As will be described later, in this case, c is set to cg (see md ), k md =kg (see tb ), so the operation result of the addition and subtraction unit 401 becomes (T asst +N·T MD，cmd -cg·dθ MD，cmd / dt-kg·θ MD，cmd ).

[0349] In this case, the manual steering operation command value generation unit 45A calculates the manual steering operation command value θ based on the following equation of motion (12). md .

[0350] [Mathematical formula 10]

[0351]

[0352]

[0353] In Equation (12), J 2 ·d MD，cmd θ 2 / dt MD，cmd is the moment of inertia. cg·dθ MD，cmd / dt is the imaginary shock absorber reaction force. kg·θ md is the imaginary spring reaction force.

[0353] That is, when the vehicle is in a state of facing away from the deviation side, the manual steering operation command value generation unit 45A uses cg·dθ col / dt as the imaginary shock absorber reaction force c MD，cmd ·dθ md / dt in the equation of motion of the above Equation (11), and uses kg·θ col ·θ MD，cmd as the imaginary spring reaction force k MD，cmd in the equation of motion of the above Equation (11) to calculate the manual steering operation command value θMD，cmd .

[0354] When in a state where the vehicle is facing the deviation side and the lateral deviation e L is greater than -e L，S and less than e L，S , the addition result X of the third adder 414 becomes k md ·θ MD，cmd . Therefore, the operation result of the addition / subtraction unit 401 becomes (T tb +N·T asst -c md ·dθ MD，cmd / dt-k md ·θ MD，cmd ). As described later, in this case, c is set to be md =cr(e L )(see Figure 22 ), and k md =kr(see Figure 21 ). So the operation result of the addition / subtraction unit 401 becomes (T tb +N·T asst -cr(e L )·dθ MD，cmd / dt-kr·θ MD，cmd ).

[0355] In this case, the manual steering operation command value generation unit 45A calculates the manual steering operation command value θ based on the following equation of motion (13). MD，cmd .

[0356] [Mathematical formula 11]

[0357]

[0358] In Equation (13), J md ·d 2 θ MD，cmd / dt 2 is the moment of inertia. cr(e L )·dθ MD，cmd is the imaginary shock absorber reaction force. kr·θ MD，cmd is the imaginary spring reaction force.

[0359] That is, in the LCA mode, the manual steering operation command value generation unit 45A uses cr(e md ·dθ col / dt corresponding to the lateral deviation e L as the imaginary shock absorber reaction force c L )·dθ MD，cmd / dt, as the imaginary spring reaction force k in the equation of motion of the above formula (11) md ·θ col Use kr·θ MD，cmd to calculate the manual steering operation command value θ MD，cmd . Therefore, in the LCA mode, compared with the case where the vehicle is in a state of avoiding the deviation side, the imaginary shock absorber reaction force and the imaginary spring reaction force can be increased.

[0360] When the vehicle is in a state of facing the deviation side and the lateral deviation e L is -e L，S or when e L，S is above a certain value, the addition result X of the third addition unit 414 becomes T tb，d (e L ) + N·T asst ). Therefore, the operation result of the addition and subtraction unit 401 becomes (T tb -c md ·dθ MD，cmd / dt - T tb，d (e L ). As will be described later, in this case, c md is set to cr(e L ) (see Figure 22 ), so the operation result of the addition and subtraction unit 401 becomes (T tb -cr(e L )·dθ MD，cmd / dt - T tb，d (e L ).

[0361] In this case, the manual steering operation command value generation unit 45A calculates the manual steering operation command value θ based on the equation of motion of the following formula (14) MD，cmd .

[0362] [Mathematical formula 12]

[0363]

[0364] In formula (14), J md ·d 2 θ MD，cmd / dt 2 is the moment of inertia. cr(e L )·dθ MD，cmd is the imaginary shock absorber reaction force. T tb，d (e L ) is the target imaginary spring reaction force.

[0365] That is, in the LKA mode, the manual steering operation command value generation unit 45A sets N·T m (= N·T asst ) in the equation of motion of the above formula (11) to 0, and uses the imaginary shock absorber reaction force cr(e md ·dθ col ) / dt corresponding to the lateral deviation e L as the imaginary shock absorber reaction force c L ·dθ MD，cmd / dt in the equation of motion of the above formula (11), and uses the target imaginary spring reaction force T md (e col ) corresponding to the lateral deviation e L as the imaginary spring reaction force k tb，d ·θ L in the equation of motion of the above formula (11) to calculate the manual steering operation command value θ MD，cmd .

[0366] Therefore, in the LKA mode, the imaginary shock absorber reaction force can be increased compared with the case where the vehicle is in a state of avoiding the deviation side. In addition, in the LKA mode, compared with the LCA mode, the steering operation reaction force corresponding to the lateral deviation e L can be applied to the driver. Thus, the driver can easily recognize the distance from the center of the driving lane or the distance to the lane.

[0367] In addition, in Figure 24 , although the operation result N·T asst of the reduction ratio multiplication unit 431 is provided to the first adder 410, it is also possible not to provide the operation result N·T asst of the reduction ratio multiplication unit 431 to the first adder 410. In this case, in the LKA mode, the manual steering operation command value generation unit 45A calculates the manual steering operation command value asst based on the equation of motion obtained by adding N·T MD，cmd to the right side of the above formula (14).

[0368] Figure 25A And Figure 25B are flowcharts showing the steps of the coefficient / weight setting process performed by the equation of motion setting unit 43A in the driving assistance mode. Figure 25A And Figure 25B The coefficient / weight setting process shown starts each time the driving assistance mode is started and is repeatedly executed in units of a prescribed operation cycle until the driving assistance mode is canceled.

[0369] The equation of motion setting unit 43A first obtains the lateral deviation e Land the automatic steering operation command value θ AD，cmd and the actual steering operation angle θ calculated by the reduction ratio division unit 42 (step S31).

[0370] Next, the motion equation setting unit 43A determines whether the lateral deviation e L is less than 0 (step S32). In other words, the motion equation setting unit 43A determines the sign of the lateral deviation e L is negative.

[0371] When the lateral deviation e L is less than 0 (step S32: Yes), the motion equation setting unit 43A determines the angular deviation Δθ AD，cmd between the actual steering operation angle θ and the automatic steering operation command value θ A (= θ - θ AD，cmd ) and determines whether the time differential value dΔθ A / dt is greater than or equal to a specified threshold value β (where β > 0) (step S33).

[0372] When the time differential value dΔθ A / dt is greater than or equal to β (step S33: Yes), the motion equation setting unit 43A determines that the vehicle is in a state of turning toward the avoidance deviation side (non-deviation side), and proceeds to step S34.

[0373] In step S34, the motion equation setting unit 43A sets the third weight W3 to 1, sets the fourth weight W4 to 0, sets the second imaginary load spring stiffness coefficient kg to the imaginary load spring stiffness coefficient k md , and sets the second imaginary load viscous damping coefficient cg to the imaginary load viscous damping coefficient c md . Thus, the manual steering operation command value generation unit 45A calculates the manual steering operation command value θ MD，cmd based on the above formula (12). If the process of step S34 is performed, the motion equation setting unit 43A ends the processing of this calculation cycle.

[0374] In step S33 above, when it is determined that the time differential value dΔθ A / dt is less than β (step S33: No), the motion equation setting unit 43A determines that the vehicle is in a state of turning toward the deviation side, and proceeds to step S35.

[0375] In step S35, the motion equation setting unit 43A sets the third weight W3 to 0 and sets the fourth weight W4 to 1. Also, the motion equation setting unit 43A sets the first imaginary load viscous damping coefficient cr(e L ) to the imaginary load viscous damping coefficient c md. Specifically, the motion equation setting unit 43A is based on the storage of Figure 22 with respect to the lateral deviation e L of the first imaginary load viscous damping coefficient cr(e L ), and the lateral deviation e obtained in step S31 L , and the first imaginary load viscous damping coefficient cr(e corresponding to this lateral deviation e L ) value is set as the imaginary load viscous damping coefficient c L . md .

[0376] Moreover, the motion equation setting unit 43A determines whether the lateral deviation e L is greater than -e L，S and less than e L，S , that is, whether the LCA mode condition is satisfied (step S36).

[0377] When the LCA mode condition is satisfied (step S36: Yes), the motion equation setting unit 43A sets the fifth weight W5 to 1, sets the sixth weight W6 to 0, and sets the first imaginary load spring stiffness coefficient kr to the imaginary load spring stiffness coefficient k md (step S37). Thus, the manual steering operation command value generation unit 45A calculates the manual steering operation command value θ based on the above formula (13) MD，cmd . If the process of step S37 is performed, the motion equation setting unit 43A ends the processing of this operation cycle.

[0378] In the above step S36, when it is determined that the LCA mode condition is not satisfied (step S36: No), the motion equation setting unit 43A sets the fifth weight W5 to 0 and sets the sixth weight W6 to 1 (step S38). Thus, the manual steering operation command value generation unit 45A calculates the manual steering operation command value θ based on the above formula (14) MD，cmd . If the process of step S38 is performed, the motion equation setting unit 43A ends the processing of this operation cycle.

[0379] In the above step S32, when it is determined that the lateral deviation e L is 0 or more (step S32: No), the motion equation setting unit 43A determines whether the time differential value dΔθ A / dt is -β or less (step S39).

[0380] When the time differential value dΔθ A / dt is -β or less (step S39: Yes), the motion equation setting unit 43A determines that the vehicle is in a state of avoiding the deviation side and moves to step S40.

[0381] In step S40, the motion equation setting unit 43A sets the third weight W3 to 1, sets the fourth weight W4 to 0, sets the second imaginary load spring stiffness coefficient kg to the imaginary load spring stiffness coefficient k md , and sets the second imaginary load viscous damping coefficient cg to the imaginary load viscous damping coefficient c md . Thus, the manual steering operation command value generation unit 45A calculates the manual steering operation command value θ based on the above formula (12) MD，cmd . If the process of step S40 is performed, the motion equation setting unit 43A ends the process of this calculation cycle

[0382] In the above step S39, when it is determined that the time differential value dΔθ A / dt is greater than -β (step S39: No), the motion equation setting unit 43A determines that the vehicle is in a state of deviating toward the deviation side and moves to step S41

[0383] In step S41, the motion equation setting unit 43A sets the third weight W3 to 0 and sets the fourth weight W4 to 1. The motion equation setting unit 43A also sets the first imaginary load viscous damping coefficient cr(e L ) to the imaginary load viscous damping coefficient c md .

[0384] Moreover, the motion equation setting unit 43A determines whether the lateral deviation e L is greater than -e L，S and less than e L，S to satisfy the LCA mode condition (step S42)

[0385] When the LCA mode condition is satisfied (step S42: Yes), the motion equation setting unit 43A sets the fifth weight W5 to 1, sets the sixth weight W6 to 0, and sets the first imaginary load spring stiffness coefficient kr to the imaginary load spring stiffness coefficient k md (step S43). Thus, the manual steering operation command value generation unit 45A calculates the manual steering operation command value θ based on the above formula (13) MD，cmd . If the process of step S43 is performed, the motion equation setting unit 43A ends the process of this calculation cycle

[0386] In the above step S42, when it is determined that the LCA mode condition is not satisfied (step S42: No), the motion equation setting unit 43A sets the fifth weight W5 to 0 and sets the sixth weight W6 to 1 (step S44). Thus, the manual steering operation command value generation unit 45A calculates the manual steering operation command value θ based on the above formula (14) MD，cmdIf the process of step S44 is performed, the motion equation setting unit 43A ends the process for this operation cycle.

[0387] [Explanation of a modification example of coefficient / weight setting process]

[0388] Preferably, when the virtual load spring stiffness coefficient k md is switched from the first virtual load spring stiffness coefficient kr to the second virtual load spring stiffness coefficient kg, the virtual load spring stiffness coefficient k md is decreased from the first virtual load spring stiffness coefficient kr to the second virtual load spring stiffness coefficient kg. Preferably, when the virtual load spring stiffness coefficient k md is switched from the second virtual load spring stiffness coefficient kg to the first virtual load spring stiffness coefficient kr, the virtual load spring stiffness coefficient k md is increased from the first virtual load spring stiffness coefficient kr to the second virtual load spring stiffness coefficient.

[0389] Preferably, when the virtual load viscous damping coefficient c md is switched from the first virtual load viscous damping coefficient cr(e L ) to the second virtual load viscous damping coefficient cg, the virtual load viscous damping coefficient c md is decreased from the first virtual load viscous damping coefficient cr(e L ) to the second virtual load viscous damping coefficient cg. Preferably, when the virtual load viscous damping coefficient c md is switched from the second virtual load viscous damping coefficient cg to the first virtual load viscous damping coefficient cr(e L ), the virtual load viscous damping coefficient c md is increased from the second virtual load viscous damping coefficient cg to the first virtual load viscous damping coefficient cr(e L ).

[0390] Preferably, when the third weight W3 is switched from 1 to 0, the third weight W3 is decreased from 1 to 0. Similarly, preferably, when the third weight W3 is switched from 0 to 1, the third weight W3 is increased from 0 to 1. The same applies to the other weights W4 to W6.

[0391] In the case where 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 the manual steering operation command value θ MD，cmd is not reflected in the motor torque command value T m，cmd . In other words, the steering reaction force based on the manual steering operation command value θ MD，cmd is not reflected. However, in order to enable the manual steering operation command value generation unit 45A to continue the manual steering operation command value θ even in the normal modeMD，cmd The operation action can also cause the motion equation setting unit 43A to set the imaginary load spring stiffness coefficient k md , the imaginary load viscous damping coefficient c md and the target imaginary spring reaction force T tb，d (e L ).

[0392] In this case, when the driving mode is the normal mode, the motion equation setting unit 43A sets the imaginary load spring stiffness coefficient k md to the preset specified value k M , sets the imaginary load viscous damping coefficient c md to the preset specified value c M , and sets the target imaginary spring reaction force T tb，d (e L ) to the preset specified value T tb，dM . k M For example, it can also be set to Figure 21 k1. c M For example, it can also be set to Figure 22 c1. T tb，dM For example, it can also be set to Figure 20 T tb，d，S .

[0393] In addition, in the normal mode, the operation of the manual steering operation command value generation unit 45A can also be stopped. In this case, in the normal mode, the motion equation setting unit 43A can also set the imaginary load spring stiffness coefficient k md , the imaginary load viscous damping coefficient c md and the target imaginary spring reaction force T tb，d (e L ).

[0394] In addition, in step S33, when it is determined that the time differential value dΔθ A / dt is less than β (step S33: No), as shown by the dashed step S51 in Figure 25A , the third weight W3 and the fifth weight W5 can also be set to 0, the fourth weight W4 and the sixth weight W6 can be set to 1, and the first imaginary load viscous damping coefficient cr(e L ) can be set to the imaginary load viscous damping coefficient c md .

[0395] Similarly, in step S39, when it is determined that the time differential value dΔθ A / dt is greater than -β (step S39: No), as shown in Figure 25BAs shown by the step S52 of the dashed line, the third weight W3 and the fifth weight W5 can also be set to 0, and the fourth weight W4 and the sixth weight W6 can be set to 1. The first imaginary load viscous damping coefficient cr(e L ) is set to the imaginary load viscous damping coefficient c md .

[0396] In addition, in the above modification, although the imaginary load viscous damping coefficient c md is switched when it is determined that the vehicle is in a state of facing the avoidance deviation side and when it is determined that the vehicle is in a state of facing the deviation side, the switching may not be performed during the above period. Specifically, the value of the imaginary load viscous damping coefficient c md may also be a fixed value.

[0397] Figure 19 [Explanation of the modification example of the manual steering command value generation unit]

[0398] Instead of Figure 19 the manual steering command value generation unit 45A, as Figure 19 shown by the dashed line, a manual steering command value generation unit 45B that also substitutes the automatic steering command value θ AD .c md can be used. Hereinafter, the motor control ECU 202B that uses the manual steering command value generation unit 45B instead of the manual steering command value generation unit 45A is referred to as the second modification example of the motor control ECU.

[0399] Figure 26 is a block diagram showing the configuration of the manual steering command value generation unit 45B. In Figure 26 , parts corresponding to the respective parts of the above Figure 19 are labeled and shown with the same reference numerals as Figure 19 .

[0400] The manual steering command value generation unit 45B 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 imaginary shock absorber reaction force calculation unit 405, a first imaginary spring reaction force calculation unit 406, a third weight multiplication unit 407, a second imaginary spring reaction force calculation unit 408, a fifth weight multiplication unit 409, a first order differential unit 421, a second imaginary shock absorber reaction force calculation unit 422, a second order differential 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.

[0401] In Figure 26 ​In the manual steering operation command value generation unit 45B, compared with Figure 24 the manual steering operation command value generation unit 45A, a first-order differentiator 421, a second imaginary shock absorber reaction force calculation unit 422, a second-order differentiator 423, and an inertia multiplier 424 are added.

[0402] The first-order differentiator 421 performs a first-order differentiation on the automatic steering operation command value θ AD，cmd . The second imaginary shock absorber reaction force calculation unit 422 calculates the second imaginary shock absorber reaction force c AD，cmd by multiplying the first-order differential value dθ AD，cmd / dt of the automatic steering operation command value θ md by the imaginary load viscous damping coefficient c md , resulting in c AD，cmd ·dθ md / dt. The second imaginary shock absorber reaction force c AD，cmd ·dθ AD，cmd / dt is the imaginary shock absorber reaction force with respect to the automatic steering operation command value θ md ·dθ md，cmd / dt is hereinafter referred to as the first imaginary shock absorber reaction force.

[0403] The second-order differentiator 423 performs a second-order differentiation on the automatic steering operation command value θ AD，cmd . The inertia multiplier 424 calculates the inertia moment J AD，cmd with respect to the automatic steering operation command value θ 2 θ AD，cmd / dt 2 by multiplying the second-order differential value d md θ AD，cmd / dt md by the column inertia J 2 θ AD，cmd / dt 2 .

[0404] The first adder 410 adds the imaginary shock absorber reaction force (second imaginary shock absorber reaction force) c AD，cmd ·dθ md / dt with respect to the automatic steering operation command value θ AD，cmd to the inertia moment J AD，cmd ·d md θ 2 / dt AD，cmd with respect to the automatic steering operation command value θ 2 , the target imaginary spring reaction force T tb，d (e L) and the auxiliary torque command value N·T with respect to the output shaft 9 asst .

[0405] The sixth weight multiplication unit 411 multiplies the operation result (c md ·dθ AD，cmd / dt + J md ·d 2 θ AD，cmd / dt 2 + T tb，d (e L ) + N·T asst ) by the sixth weight W6.

[0406] The second addition unit 412 adds the operation result W5·k md ·θ MD，cmd of the fifth weight multiplication unit 409, and the operation result W6·(c md ·dθ AD，cmd / dt + J md ·d 2 θ AD，cmd / dt 2 + T tb，d (e L ) + N·T asst ).

[0407] The fourth weight multiplication unit 413 multiplies the operation 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 )} of the second addition unit 412 by the fourth weight W4.

[0408] The third addition unit 414 adds the operation result W3·k md ·θ MD，cmd of the third weight multiplication unit 407, and the operation 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·Tasst )} Add. The addition result [{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 to the addition / subtraction unit 401 as Y.

[0409] In this modification, the equation of motion setting unit 43A also performs the same process as the coefficient / weight setting process described using Figure 25A and Figure 25B in the driving assistance mode.

[0410] Therefore, when the vehicle is in a state of facing the avoidance deviation side (non-deviation side), the third weight W3 is set to 1 and the fourth weight W4 is set to zero. On the other hand, when the vehicle is in a state of facing the deviation side, the third weight W3 is set to zero and the fourth weight W4 is set to 1.

[0411] In addition, when the vehicle is in a state of facing the deviation side, when the lateral deviation e L is larger than -e L，S and smaller than e L，S , the driving assistance mode becomes the LCA mode, the fifth weight W5 is set to 1, and the sixth weight W6 is set to zero.

[0412] On the other hand, when the vehicle is in a state of facing the deviation side, when the lateral deviation e L is -e L，S or less or e L，S or more, the driving assistance mode becomes the LKA mode, the fifth weight W5 is set to zero, and the sixth weight W6 is set to 1.

[0413] When the vehicle is in a state of facing the avoidance deviation side (non-deviation side), the addition result Y of the third addition unit 414 becomes k md ·θ MD，cmd . Therefore, the operation result of the addition / subtraction unit 401 becomes (T tb +N·T asst -c md ·dθ MD，cmd / dt-k md ·θ MD，cmd)。In this case, it is set to c md = cg (reference Figure 22 ), k md = kg (reference Figure 21 ), so the operation result of the addition / subtraction unit 401 becomes (T tb + N·T asst - cg·dθ MD，cmd / dt - kg·θ MD，cmd ).

[0414] In this case, the manual steering operation command value generation unit 45B calculates the manual steering operation command value θ MD，cmd .

[0415] When it is in the state where the vehicle is facing the deviation side and the lateral deviation e L is larger than -e L，S and smaller than e L，S , the addition result Y of the third addition unit 414 becomes k md ·θ MD，cmd . Therefore, the operation result of the addition / subtraction unit 401 becomes (T tb + N·T asst - c md ·dθ MD，cmd / dt - k md ·θ MD，cmd ). In this case, it is set to c md = cr(e L )(reference Figure 22 ), k md = kr (reference Figure 21 ), so the operation result of the addition / subtraction unit 401 becomes (T tb + N·T asst - cr(e L )·dθ MD，cmd / dt - kr·θ md，cmd ).

[0416] In this case, the manual steering operation command value generation unit 45B calculates the manual steering operation command value θ MD .

[0417] Therefore, in the LCA mode, compared with the case where the vehicle is in the state of avoiding the deviation side, the virtual shock absorber reaction force and the virtual spring reaction force can be increased.

[0418] When it is in the state where the vehicle is facing the deviation side and the lateral deviation e L is -e L，S or less, or e L，SIn the above case, the addition result Y of the third adder 414 becomes (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 operation result of the addition / subtraction unit 401 becomes (T tb - c md ·dθ MD，cmd / dt - c md ·dθ AD，cmd / dt - J md ·d2θ AD，cmd / dt2 - T tb，d (e L ). In this case, it is set that c md = cr(e L ) (see Figure 22 ), so the operation result of the addition / subtraction unit 401 becomes {(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 )}.

[0419] In this case, the manual steering operation command value generation unit 45B calculates the manual steering operation command value θ MD .

[0420] [Mathematical formula 13]

[0421]

[0422] In formula (15), (J md ·d 2 θ MD，cmd / dt 2 + J md ·d 2 θ AD，cmd / dt 2 ) is the inertial moment. (cr(e L )·dθ MD，cmd / dt + cr(e L )·dθ AD，cmd / dt) is the reaction force of the imaginary shock absorber. T tb，d (e L ) is the target imaginary spring reaction force.

[0423] That is, in the LKA mode, the manual steering operation command value generation unit 45B sets N·T in the equation of motion of the above formula (11) m (= N·T asst ) to 0, and uses it as the moment of inertia J in the above formula (11) md ·d 2 θ col / dt 2 , the reaction force c of the imaginary shock absorber md ·dθ col / dt and the reaction force k of the imaginary spring md ·θ col , and respectively use (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 calculate the manual steering operation command value θ MD，cmd .

[0424] Therefore, in the LKA mode, compared with the case where the vehicle is in a state of avoiding the deviation side, the reaction force of the imaginary shock absorber can be increased. In addition, in the LKA mode, compared with the LCA mode, a steering operation reaction force corresponding to the lateral deviation e L can be applied to the driver. Thus, the driver can easily recognize the distance from the center of the driving lane or the distance to the lane.

[0425] In addition, in Figure 26 , although the operation result N·T of the reduction ratio multiplication unit 431 is provided to the first adder 410, it is also possible not to provide the operation result N·T of the reduction ratio multiplication unit 431 to the first adder 410 asst . In this case, in the LKA mode, the manual steering operation command value generation unit 45B calculates the manual steering operation command value θ asst based on the equation of motion obtained by adding N·T asst to the right side of the above formula (15). MD，cmd .

[0426] In the second modification example of the motor control ECU, the same effects as those of the first modification example of the above motor control ECU are achieved. In the second modification example of the motor control ECU, compared with the first modification example of the motor control ECU, in the LKA mode, the effect of being able to reduce the discomfort of the driver is achieved. Hereinafter, this will be described.

[0427] Refer to Figure 19 and Figure 5 , in the coordinated steering operation mode, the electric motor 18 is controlled in such a manner that the actual rotation angle θ follows the combined angle command value θ int，cmd . Assuming that the actual rotation angle θ completely follows the combined angle command value θ int，cmd , then the relationship of θ int，cmd = θ - θ AD，cmd holds.

[0428] In this case, the hypothetical shock absorber reaction force cr(e MD，cmd )·dθ L / dt in the above formula (15) with respect to the manual steering operation command value θ MD，cmd is represented by the following formula (16).

[0429] [Mathematical formula 14]

[0430]

[0431] In addition, the inertia moment J MD，cmd in the above formula (15) with respect to the manual steering operation command value θ md ·d 2 θ MD，cmd / dt 2 is represented by the following formula (17).

[0432] [Mathematical formula 15]

[0433]

[0434] That is, cr(e L )·dθ MD，cmd / dt includes the actual rotation angle component cr(e L )·dθ / dt corresponding to the first-order differential of the actual rotation angle θ, and the automatic steering operation component -cr(e AD，cmd )·dθ L / dt corresponding to the first-order differential of the automatic steering operation command value θ AD，cmd . Similarly, J md ·d 2 θ MD，cmd / dt 2 includes the actual rotation angle component J md ·d2 θ / dt 2 and the automatic steering control component -J corresponding to the second derivative of the automatic steering control command value θ AD，cmd ·d md ·d 2 θ AD，cmd / dt 2 .

[0435] The above actual cornering component cr(e L )·dθ / dt and J md ·d 2 θ / dt 2 correspond to the driver's actions, so the driver will not feel discomfort. On the other hand, the above automatic steering control component -cr(e L )·dθ AD，cmd / dt and -J md ·d 2 θ AD，cmd / dt 2 has nothing to do with the driver's actions, so there is a concern that the driver may feel discomfort. The absolute value of -dθ AD，cmd / dt is larger than that of -d 2 θ AD，cmd / dt 2 , so in particular, the automatic steering control component -cr(e L )·dθ AD，cmd / dt of the imaginary shock absorber reaction force is likely to have a negative impact on the steering feel.

[0436] In the second modification example of the motor control ECU, as the equation of motion of the imaginary shock absorber reaction force in the above formula (15), in addition to the imaginary shock absorber reaction force cr(e MD，cmd )·dθ L / dt with respect to the manual steering control command value θ MD，cmd it also includes the imaginary shock absorber reaction force cr(e AD，cmd )·dθ L / dt with respect to the automatic steering control command value θ AD，cmd . In addition, as the inertial moment in the equation of motion of the above formula (15), in addition to the inertial moment J MD，cmd ·d md ·d 2 θ MD，cmd / dt 2 with respect to the manual steering control command value θ AD，cmd it also includes the inertial moment J md ·d 2 θ AD，cmd / dt 2 .

[0437] This can reduce the manual steering command value θ md The hypothetical shock absorber reaction force cr(e L )·dθ MD，cmd / dt contains the automatic steering control component -cr(e L )·dθ AD，cmd / dt. Similarly, it is possible to reduce the manual steering command value θ MD，cmd The moment of inertia J md ·d 2 θ md，cmd / dt 2 Automatic steering components contained -J md ·d 2 θ AD，cmd / dt 2 As a result, the driver's discomfort can be reduced in the LKA mode.

[0438] Assuming that θ MD，cmd =θ-θ AD，cmd When such a relationship holds, the motion equation of equation (15) is expressed as follows: equation (18).

[0439] [Formula 16]

[0440]

[0441] In this case, cr(e L )·dθ MD，cmd / dt contains the automatic steering control component -cr(e L )·dθ AD，cmd / dt is compensated, and only the actual rotation angle component cr (e) relative to the actual rotation angle θ remains L )·dθ / dt. In addition, J md ·d 2 θ MD，cmd / dt 2 Automatic steering components contained -J md ·d 2 θ AD，cmd / dt 2 is compensated, leaving only J relative to the actual rotation angle θ md ·d 2 θ / dt 2 .

[0442] The contents described in the above-mentioned [Description of a Modification Example of Coefficient / Weight Setting Processing] can also be applied to Figure 19 A modified example of the manual steering command value generating unit 45A is the manual steering command value generating unit 45B.

[0443] In addition, in the first and second modified examples of the ECU for motor control, the weight setting unit 52 may also perform the same weight processing as described above in the driving assistance mode. However, Figure 9 in steps S2 and S4, α is replaced with e Figure 9 L，s (see Figures 20 - 22 ).

[0444] In this case, in the driving assistance mode, when the distance between the vehicle reference position and the center of the lane is greater than e L，S , the weight setting unit 52 sets the first weight W1 to 0 and the second weight W2 to 1. On the other hand, in the driving assistance mode, when the distance between the vehicle reference position and the center of the lane is e L，s or less, the weight setting unit 52 sets the first weight W1 to 1 and the second weight W2 to 0. Therefore, even in the driving assistance mode, when the distance between the vehicle reference position and the center of the lane is e L，s or less, the drive control of the electric motor 18 is not based on the combined motor torque command value T mint，cmd but on the auxiliary torque command value T asst .

[0445] In addition, when switching the first weight W1 from 1 to 0, it is preferable to decrease the first weight W1 from 1 to 0. Similarly, when switching the first weight W1 from 0 to 1, it is preferable to increase the first weight W1 from 0 to 1. The same applies to the second weight W2.

[0446] In addition, 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.

[0447] Although the first to fourth embodiments of the present invention, the modified examples of the weight setting unit, and the modified examples of the ECU for motor control have been described above, the present invention can also be implemented in other forms.

[0448] In the above first to fourth embodiments and the modified examples of the ECU for motor control, the distance from the center of the lane in which the vehicle is currently traveling to the vehicle reference position, that is, the lateral deviation e L , is used as the vehicle lateral position. 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.

[0449] In the above first to fourth embodiments and the modified examples of the ECU for motor control, the auxiliary torque command value T asst is multiplied by the first weight W1, and the auxiliary torque command value W1·T asst ​It is supplied to the addition unit 50. However, instead, the manual torque command value corresponding to the manual steering operation command value θ MD，cmd is multiplied by the first weight W1, and the manual torque command value after being multiplied by the first weight is supplied to the addition unit 50.

[0450] In addition, in the above-described first to fourth embodiments and the modification example of the motor control ECU, although the angle control unit 47 (refer to Figure 5 ) includes the feedforward control unit 63, the feedforward control unit 63 may be omitted. In this case, the feedback control torque T calculated by the feedback control unit 62 fb becomes the basic target torque.

[0451] In the above-described first to fourth embodiments and the modification example of the motor control ECU, although an example in which the present invention is applied to a column type EPS is shown, the present invention can also be applied to an EPS other than the column type. In addition, the present invention can also be applied to an electric power steering system.

[0452] Although the embodiments of the present invention have been described in detail, they are merely specific examples for clarifying the technical content of the present invention, and the present invention should not be construed as being limited to the above specific examples. The scope of the present invention is defined only by the appended claims.

[0453] This application corresponds to Japanese Patent Application No. 2022-181888 filed with the Japan Patent Office on November 14, 2022, and all the disclosures of this application are incorporated herein by reference.

[0454] Description of Reference Numerals

[0455] 1... Electric power steering device, 3... Steering wheel, 4... Steering mechanism, 18... Electric motor, 43... Road surface reaction force characteristic setting unit, 43A... Equation of motion setting unit, 44... Assist torque command value setting unit, 45, 45A, 45B... Manual steering operation command value generation unit, 46... Composite angle command value calculation unit, 47... Angle control unit, 48... First weight multiplication unit, 49... Second weight multiplication unit, 50... Addition unit, 51... Torque control unit, 52... Weight setting unit, 201... Host ECU, 202, 202A, 202B... Motor control ECU.

Claims

1. A motor control device for driving and controlling an electric motor of a steering control device, comprising: A manual steering command value generation unit that generates a manual steering command value using the equation of motion of a reference model of the steering control device; A combined angle command value calculation unit that calculates a combined angle command value by adding the automatic steering command value provided in the driving assistance mode to the manual steering command value; A control unit that performs angle control on the electric motor for corner control based on the combined angle command value; and An equation of motion setting unit that changes the equation of motion according to the time derivative of the angle deviation between the automatic steering command value and the actual steering angle.

2. The motor control device according to claim 1, wherein, The above-mentioned equation of motion includes a road surface reaction force characteristic coefficient. The equation of motion setting unit changes the above-mentioned equation of motion by changing the value of at least one of the road surface reaction force characteristic coefficients included in the above-mentioned equation of motion.

3. The motor control device according to claim 1, wherein, The equation of motion setting unit is configured to change the above-mentioned equation of motion by switching between a first equation of motion and a second equation of motion. In the above-mentioned first equation of motion, as the imaginary spring reaction force, a target imaginary spring reaction force corresponding to the lateral position of the vehicle reference position with respect to the driving lane is used. In the above-mentioned second equation of motion, as the imaginary spring reaction force, an imaginary spring reaction force set with an imaginary load spring stiffness coefficient that uses a constant value regardless of the above-mentioned lateral position is used.

4. The 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 in a state of facing the deviation side or a state of facing away from the deviation side based on either the lateral position of the vehicle reference position with respect to the driving lane and the above-mentioned angle deviation, or the above-mentioned time differential value, and change the above-mentioned equation of motion based on the determination result.

5. The motor control device according to claim 2, wherein, The equation of motion setting unit determines whether the vehicle is in a state of facing the deviation side or a state of facing away from the deviation side based on either the lateral position of the vehicle reference position with respect to the driving lane and the above-mentioned angle deviation, or the above-mentioned time differential value. In the state where the vehicle is facing away from the deviation side, the value of at least one of the road surface reaction force characteristic coefficients included in the above-mentioned equation of motion is reduced compared to the state where the vehicle is facing the deviation side.

6. The motor control device according to claim 2, wherein, The equation of motion setting unit determines whether the vehicle is in a state of facing the deviation side or a state of facing away from the deviation side based on either the lateral position of the vehicle reference position with respect to the driving lane and the above-mentioned angle deviation, or the above-mentioned time differential value. In the state where the vehicle is facing the deviation side, at least one of the road surface reaction force characteristic coefficients included in the above-mentioned equation of motion is changed according to the above-mentioned lateral position.

7. The motor control device according to claim 3, wherein, The equation of motion setting unit uses the above-mentioned time differential value to determine whether the vehicle is in a state of facing the deviation side or a state of facing away from the deviation side. In the state where the vehicle is facing the deviation side, the above-mentioned first equation of motion is set as the above-mentioned equation of motion, and in the state where the vehicle is facing away from the deviation side, the above-mentioned second equation of motion is set as the above-mentioned equation of motion.

Images