Motor control device

Abstract

This motor control device comprises: an assist torque command value generation unit that generates an assist torque command value using a steering torque; a manual steering command value generation unit that generates a manual steering command value using the steering torque and the assist torque command value; an integrated angle command value calculation unit that calculates an integrated angle command value by adding the manual steering command value to an automatic steering command value for driving assistance; and a switching unit that, in driving assistance mode, switches between a first control mode, in which an electric motor is controlled on the basis of the assist torque command value or the manual steering command value, and a second control mode, in which the electric motor is controlled on the basis of the integrated angle command value, according to the lateral position of the vehicle with respect to the lane.

Description

[Technical Field]

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

[0002] Patent Document 1 below discloses the following vehicle steering device. That is, in a driving assistance mode, a steering assist current is calculated. A risk level is calculated, and a steering reaction force gain is calculated based on the risk level. A steering reaction force control current is calculated by multiplying the deviation between a target steering angle for steering assistance and the steering angle by the steering reaction force gain, and a steering assist correction gain is calculated based on the steering reaction force gain. An actuator drive current is calculated by adding a value obtained by multiplying the steering assist current by the steering assist correction gain to the steering reaction force control current, and an actuator (electric motor) is driven and controlled based on the actuator drive current. In this way, a reaction force according to the risk is generated, and the risk state is communicated to the driver. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2010-30505 Summary of the Invention [Problem to be solved by the invention]

[0004] 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 driving assistance mode using a novel method. [Means for solving the problem]

[0005] One embodiment of the present invention provides a motor control device for drive control of an electric motor for steering angle control, including an assist torque command value generation unit that generates an assist torque command value using steering torque, a manual steering command value generation unit that generates a manual steering command value using the steering torque and the assist torque command value, an integrated angle command value calculation unit that calculates an integrated angle command value by adding the manual steering command value to an automatic steering command value for driving assistance, and a switching unit that, in a driving assistance mode, switches between a first control mode in which the electric motor is controlled based on the assist torque command value or the manual steering command value, and a second control mode in which the electric motor is controlled based on the integrated angle command value, depending on the lateral position of the vehicle with respect to the lane.

[0006] The above and other objects, features and advantages of the present invention will become apparent from the following description of the embodiments with reference to the accompanying drawings. [Brief explanation of the drawings]

[0007] [Figure 1] FIG. 1 is a schematic diagram showing the general configuration of an electric power steering system to which a motor control device according to one embodiment of the present invention is applied. [Figure 2] FIG. 2 is a block diagram showing the electrical configuration of the motor control ECU. [Figure 3] FIG. 3 is a graph showing an example of setting the assist torque command value Tasst relative to the torsion bar torque Ttb. [Figure 4] FIG. 4 is a schematic diagram showing an example of a reference EPS model used in the manual steering command value generating unit. [Figure 5] FIG. 5 is a graph showing an example of setting the virtual load spring component kvl with respect to the vehicle lateral position Plat. [Figure 6] FIG. 6 is a graph showing an example of setting the virtual load viscous damping coefficient cvl with respect to the vehicle lateral position Plat. [Figure 7] FIG. 7 is a block diagram showing the configuration of the angle control unit. [Figure 8]FIG. 8 is a schematic diagram showing an example of the configuration of a physical model of an electric power steering system. [Figure 9] FIG. 9 is a block diagram showing the configuration of the disturbance torque estimating unit. [Figure 10] FIG. 10 is a schematic diagram showing the configuration of the torque control unit. [Figure 11] FIG. 11 is a flowchart showing the procedure of the weight setting process performed by the weight setting unit in the driving assistance mode. [Figure 12] FIG. 12 is a graph showing an example of the relationship between the vehicle lateral position Plat and the absolute value |Trl| of the road load torque Trl calculated based on the equation (1). [Figure 13] FIG. 13 is a schematic diagram for explaining the steering reaction force generated based on the road load torque Trl in the driving assistance mode. [Figure 14] FIG. 14 is a schematic diagram for explaining the steering reaction force generated based on the virtual road load torque Trl in the driving assistance mode when the first vehicle lateral position and the second vehicle lateral position are set to the same position. [Figure 15] FIG. 15 is a block diagram showing the electrical configuration of a motor control ECU including a weight setting unit according to the second modification. [Figure 16] FIG. 16 is a flowchart showing the procedure of the weight setting process performed by the weight setting unit according to the second modification in the driving assistance mode. [Figure 17] FIG. 17 is a schematic diagram for explaining the steering reaction force generated based on the virtual road surface load torque Trl when the weight setting process is performed according to the procedure of FIG. [Figure 18] FIG. 18 is a schematic diagram for explaining the heading angle θvh. [Figure 19] FIG. 19 is a graph showing an example of setting the virtual load spring stiffness coefficient kvl with respect to the vehicle lateral position Plat. [Figure 20] FIG. 20 is a graph showing an example of the basic characteristics of the spring stiffness coefficient kvl. [Figure 21]FIG. 21 is a graph showing an example of weighting characteristics with respect to the heading angle θvh. [Figure 22] FIG. 22 is a graph showing an example of setting the virtual load viscous damping coefficient cvl with respect to the vehicle lateral position Plat. [Figure 23] FIG. 23 is a graph showing an example of the relationship between the vehicle lateral position Plat and the absolute value |Trl| of the road load torque Trl calculated based on the equation (10). [Figure 24] FIG. 24 is a flowchart showing the procedure of the weight setting process performed by the weight setting unit according to the third modified example in the driving assistance mode. [Figure 25] FIG. 25 is a schematic diagram illustrating the steering reaction force generated based on the virtual road load torque Trl in the driving assistance mode when the first vehicle lateral position is set to PL1, PR1 and the second vehicle lateral position is set to PL2, PR2. [Figure 26] FIG. 26 is a flowchart showing the procedure of the weight setting process performed by the weight setting unit according to the fourth modification in the driving assistance mode. [Figure 27] FIG. 27 is a schematic diagram illustrating the steering reaction force generated based on the virtual road load torque Trl in the driving assistance mode when the first vehicle lateral position is set to PL3, PR3 and the second vehicle lateral position is set to PL4, PR4. [Figure 28] FIG. 28 is a block diagram showing an example of a motor control ECU when lane keep assist (LKA) control and lane centering assist (LCA) control are used in combination. [Figure 29] FIG. 29 is a graph showing an example of setting the virtual load spring stiffness coefficient kvl with respect to the vehicle lateral position Plat. [Figure 30] FIG. 30 is a schematic diagram showing an example of a target vibration waveform. [Figure 31] FIG. 31 is a graph showing an example of the relationship between the vehicle lateral position Plat and the absolute value |Treac| of the steering reaction force Treac when the characteristic of the virtual load spring stiffness coefficient kvl is the characteristic shown in FIG. 29 and the characteristic of the virtual load viscous damping coefficient cvl is similar to the characteristic shown in FIG. 29. DETAILED DESCRIPTION OF THE INVENTION

[0008] [Description of the embodiment of the present invention] One embodiment of the present invention provides a motor control device for drive control of an electric motor for steering angle control, including an assist torque command value generation unit that generates an assist torque command value using steering torque, a manual steering command value generation unit that generates a manual steering command value using the steering torque and the assist torque command value, an integrated angle command value calculation unit that calculates an integrated angle command value by adding the manual steering command value to an automatic steering command value for driving assistance, and a switching unit that, in a driving assistance mode, switches between a first control mode in which the electric motor is controlled based on the assist torque command value or the manual steering command value, and a second control mode in which the electric motor is controlled based on the integrated angle command value, depending on the lateral position of the vehicle with respect to the lane.

[0009] In one embodiment of the present invention, a first lateral position, which is the lateral position at which the first control mode switches to the second control mode, and a second lateral position, which is the lateral position at which the second control mode switches to the first control mode, are set in advance, and the steering reaction force applied to the vehicle when the vehicle moves from the lane boundary of the lane to the second lateral position has a first characteristic in which the reduction rate of the steering reaction force is large, and a second characteristic that is continuous with the first characteristic and in which the reduction rate of the steering reaction force is smaller than the first characteristic.

[0010] In one embodiment of the present invention, a first lateral position, which is the lateral position at which the first control mode switches to the second control mode, and a second lateral position, which is the lateral position at which the second control mode switches to the first control mode, are set to different positions.

[0011] In one embodiment of the present invention, the second lateral position is set closer to the center of the lane than the first lateral position.

[0012] In one embodiment of the present invention, the first lateral position is set closer to the center of the lane than the second lateral position.

[0013] In one embodiment of the present invention, the manual steering command value is calculated in consideration of a virtual road load torque.

[0014] In one embodiment of the present invention, the virtual road load torque is set according to the lateral position of the vehicle relative to the lane.

[0015] 7. The motor control device according to claim 6, wherein in one embodiment of the present invention, the virtual road load torque is set in accordance with an angle formed by the traveling direction of the vehicle with respect to the lane.

[0016] In one embodiment of the present invention, the virtual road load torque is set based on information about the outside of the lane in which the vehicle is traveling.

[0017] Detailed Description of the Embodiments of the Invention Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

[0018] FIG. 1 is a schematic diagram showing the general configuration of an electric power steering system to which a steering device according to one embodiment of the present invention is applied.

[0019] The electric power steering system 1 includes a steering wheel (handle) 2 as a steering member for steering the vehicle, a steering mechanism 4 that steers steered wheels 3 in conjunction with the rotation of the steering wheel 2, and a steering assist mechanism 5 that assists the driver in steering. The steering wheel 2 and the steering mechanism 4 are mechanically connected via a steering shaft 6 and an intermediate shaft 7.

[0020] The steering shaft 6 includes an input shaft 8 connected to the steering wheel 2 and an output shaft 9 connected to the intermediate shaft 7. The input shaft 8 and the output shaft 9 are connected via a torsion bar 10 so as to be capable of relative rotation.

[0021] 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 amount of relative rotational displacement between the input shaft 8 and the output shaft 9. tb In this embodiment, the torsion bar torque T tb For example, the torque for steering left is detected as a positive value, and the torque for steering right is detected as a negative value. The larger the absolute value of the torque, the greater the torsion bar torque T tb The magnitude of the torsion bar torque T tb is an example of the "steering torque" of the present invention.

[0022] The steering mechanism 4 is made up of a rack-and-pinion mechanism including a pinion shaft 13 and a rack shaft 14 as a steering shaft. The steered wheels 3 are connected to each end of the rack shaft 14 via tie rods 15 and knuckle arms (not shown). The pinion shaft 13 is connected to the intermediate shaft 7. The pinion shaft 13 rotates in conjunction with the steering of the steering wheel 2. A pinion 16 is connected to the tip of the pinion shaft 13.

[0023] The rack shaft 14 extends linearly in the left-right direction of the vehicle. A rack 17 that meshes with the pinion 16 is formed in the middle of the rack shaft 14 in the axial direction. The pinion 16 and the rack 17 convert the rotation of the pinion shaft 13 into axial movement of the rack shaft 14. By moving the rack shaft 14 in the axial direction, the steered wheels 3 can be steered.

[0024] When the steering wheel 2 is steered (rotated), this rotation is transmitted to the pinion shaft 13 via the steering shaft 6 and the intermediate shaft 7. The rotation of the pinion shaft 13 is then converted into axial movement of the rack shaft 14 by the pinion 16 and the rack 17. As a result, the steered wheels 3 are steered.

[0025] The steering assist mechanism 5 includes an electric motor 18 for generating a steering assist force (assist torque), and a reducer 19 for amplifying the output torque of the electric motor 18 and transmitting it to the steering mechanism 4. The reducer 19 is made up of a worm gear mechanism including a worm gear 20 and a worm wheel 21 that meshes with the worm gear 20. The reducer 19 is housed in a gear housing 22 that serves as a transmission mechanism housing.

[0026] In the following, the reduction ratio (gear ratio) of the reducer 19 may be expressed as N. The reduction ratio N is determined by the rotation angle of the worm wheel 21, that is, the worm wheel angle θ ww The worm gear angle θ is the rotation angle of the worm gear 20 relative to the wg The ratio (θ wg / θ ww )

[0027] The worm gear 20 is rotationally driven by an electric motor 18. In addition, the worm wheel 21 is connected to the output shaft 9 so as to be integrally rotatable therewith.

[0028] When the worm gear 20 is rotationally driven by the electric motor 18, the worm wheel 21 is rotationally driven, and motor torque is applied to the steering shaft 6, causing the steering shaft 6 (output shaft 9) to rotate. The rotation of the steering shaft 6 is then transmitted to the pinion shaft 13 via the intermediate shaft 7. The rotation of the pinion shaft 13 is converted into axial movement of the rack shaft 14, thereby turning the steered wheels 3. In other words, by rotating the worm gear 20 with the electric motor 18, steering assistance by the electric motor 18 and steering of the steered wheels 3 become possible. The electric motor 18 is provided with a rotation angle sensor 23 for detecting the rotation angle of the rotor of the electric motor 18.

[0029] The torque applied to the output shaft 9 (an example of a drive target of the electric motor 18) includes the motor torque from the electric motor 18 and a disturbance torque T lc Disturbance torque other than the motor torque T lc Torsion bar torque Ttb , road load torque (road reaction torque) T rl , friction torque T f etc. are included.

[0030] Torsion Bar Torque T tb is the torque applied to the output shaft 9 from the steering wheel 2 side by the force applied to the steering wheel 2 by the driver, the force generated by the steering inertia, etc.

[0031] Road load torque T rl is the torque applied to the output shaft 9 from the steered wheels 3 via the rack shaft 14 due to the self-aligning torque generated in the tires, forces generated by the suspension and tire-wheel alignment, frictional forces of the rack-and-pinion mechanism, etc.

[0032] The vehicle is equipped with a CCD (Charge Coupled Device) camera 25 that photographs the road ahead in the direction of travel of the vehicle, a GPS (Global Positioning System) 26 for detecting the vehicle's position, a radar 27 for detecting road shapes and obstacles, a map information memory 28 that stores map information, and a vehicle speed sensor 29.

[0033] The CCD camera 25, GPS 26, radar 27, map information memory 28, and vehicle speed sensor 29 are connected to a host ECU (Electronic Control Unit) 201 for performing driving assistance control. Based on the information obtained by the CCD camera 25, GPS 26, radar 27, and vehicle speed sensor 29 and map information, the host ECU 201 performs surrounding environment recognition, vehicle position estimation, route planning, etc., and determines control target values ​​for steering and drive actuators.

[0034] In this embodiment, there are two driving modes: a normal mode and a driving assistance mode. In the driving assistance mode, the host ECU 201 controls the automatic steering command value θ AD,cmdIn this embodiment, the driving assistance is a lane keep assist (LKA) for preventing the vehicle from deviating from its lane. AD,cmd is the target value of the steering angle for driving the vehicle along the target driving line.

[0035] Automatic steering command value θ AD,cmd is set based on, for example, the vehicle speed, the lateral deviation with respect to the target driving line, and the yaw deviation of the vehicle with respect to the target driving line. AD,cmd The process of setting the value is well known, so a detailed description will be omitted here.

[0036] The host ECU 201 also outputs a mode signal S indicating whether the driving mode is the normal mode or the driving assistance mode. mode , a left / right discrimination signal S indicating whether the vehicle reference position is on the left or right side of the lane center. LR and vehicle lateral position P lat The vehicle reference position is a predetermined reference position at the center of the vehicle width.

[0037] Vehicle lateral position P lat is the distance from the boundary of the lane on which the vehicle is currently traveling (hereinafter referred to as "lane boundary") to the vehicle reference position. Specifically, when the vehicle reference position is to the left of the center, the vehicle lateral position P lat is the distance from the left lane boundary to the vehicle reference position. When the vehicle reference position is to the right of the lane center, the vehicle lateral position P lat is the distance from the right lane boundary to the vehicle reference position.

[0038] Mode signal S mode , left / right discrimination signal S LR , Vehicle lateral position P lat and the automatic steering command value θ AD,cmd is given to the motor control ECU 202 via the in-vehicle network. tbThe output signal of the rotation angle sensor 23 is input to the motor control ECU 202. The motor control ECU 202 controls the electric motor 18 based on these input signals and information provided by the host ECU 201.

[0039] FIG. 2 is a block diagram showing the electrical configuration of the motor control ECU 202. As shown in FIG.

[0040] The following mainly describes the operation when the driving mode is the driving assistance mode.

[0041] The motor control ECU 202 includes a microcomputer 40, a drive circuit (inverter circuit) 31 controlled by the microcomputer 40 to supply power to the electric motor 18, and a current flowing through the electric motor 18 (hereinafter referred to as the "motor current I m The circuit includes a current detection circuit 32 for detecting the current.

[0042] The microcomputer 40 includes a CPU and memory (ROM, RAM, nonvolatile memory, etc.), and functions as a plurality of functional processing sections by executing a predetermined program. The plurality of functional processing sections include an assist torque command value setting section 41, a manual steering command value generating section 42, an integrated angle command value calculating section 43, an angle control section 44, a first weight multiplying section 45, a second weight multiplying section 46, an adding section 47, a torque control section (current control section) 48, and a weight setting section 49.

[0043] The first weight multiplier 45, the second weight multiplier 46, the adder 47, and the weight setting unit 49 are an example of the "switching unit" in the present invention.

[0044] The assist torque command value setting unit 41 sets the assist torque command value T asst The assist torque command value setting unit 41 sets the torsion bar torque T tb Based on this, the assist torque command value T asst Set the torsion bar torque Ttb Assist torque command value T asst An example of the configuration is shown in Figure 3.

[0045] Assist torque command value T asst is set to a positive value when the electric motor 18 is to generate a steering assist force for steering to the left, and is set to a negative value when the electric motor 18 is to generate a steering assist force for steering to the right. asst is the torsion bar torque T tb The torsion bar torque T tb The assist torque command value T asst is the torsion bar torque T tb The larger the absolute value of , the larger the absolute value is set.

[0046] The assist torque command value setting unit 41 acquires the vehicle speed from the host ECU 201 and calculates the vehicle speed and the torsion bar torque T tb Based on this, the assist torque command value T asst In this case, the assist torque command value T asst is the torsion bar torque T tb The higher the vehicle speed V, the higher the assist torque command value T asst is set so that the absolute value of

[0047] The assist torque command value setting unit 41 determines the torsion bar torque T tb is multiplied by a preset constant to obtain the assist torque command value T asst may be calculated.

[0048] When the driver operates the steering wheel 2, the manual steering command value generating unit 42 generates a steering angle (more precisely, a rotation angle θ of the output shaft 9) corresponding to the steering wheel operation as a manual steering command value θ MD,cmd The manual steering command value generating unit 42 is provided to set the torsion bar torque Ttb , the assist torque command value T set by the assist torque command value setting unit 41 asst and the manual steering command value θ MD,cmd The manual steering command value generating unit 42 will be described in detail later.

[0049] The integrated angle command value calculation unit 43 calculates the automatic steering command value θ set by the host ECU 201. AD,cmd , manual steering command value θ MD,cmd The integrated angle command value θ int,cmd Calculate the following.

[0050] The angle control unit 44 calculates the integrated angle command value θ int,cmd Based on this, the integrated angle command value θ int,cmd The integrated motor torque command value T mint,cmd The angle control unit 44 will be described in detail later.

[0051] The first weight multiplier 45 multiplies the assist torque command value T asst The second weight multiplier 46 multiplies the integrated motor torque command value T mint,cmd is multiplied by the second weight W2. The first weight W1 and the second weight W2 are set by the weight setting unit 49. Details of the weight setting unit 49 will be described later.

[0052] The adder 47 calculates the assist torque command value W1·T after multiplication by the first weight (after the first weighting process). asst and the integrated motor torque command value W2·T after multiplication by the second weight (after second weighting processing) mint,cmd By adding these, the motor torque command value T m,cmd Calculate the following.

[0053] The torque control unit 48 controls the motor torque of the electric motor 18 to be equal to the motor torque command value T m,cmd The driving circuit 31 is driven so that the value approaches .

[0054] In this embodiment, the manual steering command value generating unit 42 uses the reference EPS model to calculate the manual steering command value θ MD,cmd Set.

[0055] FIG. 4 is a schematic diagram showing an example of a reference EPS model used in the manual steering command value generating unit 42.

[0056] This reference EPS model is a single-inertia model including a lower column. The lower column corresponds to the output shaft 9 and the worm wheel 21. In FIG. 4, J ref is the inertia of the lower column, and T tb is the torsion bar torque. The lower column has a torsion bar torque T tb , assist torque command value T asst and road load torque T rl The rotation angle of the lower column is given by the manual steering command value θ MD,cmd Then, the road load torque (virtual road load torque) T rl is the virtual load spring stiffness coefficient k vl , virtual load viscous damping coefficient c vl and manual steering command value θ MD,cmd Using this, it is expressed by the following equation (1).

[0057] T rl =-k vl θ MD,cmd -c vl (dθ MD,cmd / dt) …(1) However, k vl =k vl (P lat ),c vl =c vl (P lat ) As shown in the above formula (1), the virtual load spring stiffness coefficient k vl and the virtual load viscous damping coefficient c vl is the vehicle lateral position P lat It is set corresponding to.

[0058] Figure 5 shows the lateral position of the vehicle P lat Virtual load spring stiffness coefficient kvl 5 is a graph showing an example of setting. The subscript L of the symbols in Fig. 5 indicates that the symbol is applied when the vehicle reference position is to the left of the center of the lane, and the subscript R indicates that the symbol is applied when the vehicle reference position is to the right of the center of the lane. The same applies to Fig. 6, which will be described later.

[0059] Vehicle lateral position P lat is the left lane boundary relative to the given P L_start or above or to the right lane boundary as specified P R_start If it is greater than or equal to the virtual load spring stiffness coefficient k vl is a predetermined value k vl,start It is set to P L_start is set to about 60 cm, for example. R_start is set to, for example, about 70 cm.

[0060] Vehicle lateral position P lat However, P L_start smaller than the given P L_small Above and P L_start If it is less than the virtual load spring stiffness coefficient k vl is the vehicle lateral position P lat P L_start The smaller the value of k (the closer the vehicle reference position is to the left lane boundary), the vl,start From k vl,L_max It is set according to the characteristics that gradually increase up to P L_small is set to, for example, about 40 cm.

[0061] Vehicle lateral position P lat However, P R_start smaller than the given P R_small That's all. R_start If it is less than the virtual load spring stiffness coefficient k vl is the vehicle lateral position P lat P R_start The smaller the value of k (the closer the vehicle reference position is to the right lane boundary), the vl,start From k vl,R_max It is set according to the characteristics that gradually increase up to P R_small is set to, for example, about 50 cm.

[0062] Vehicle lateral position P lat is P relative to the left lane boundary L_small If it is less than the virtual load spring stiffness coefficient k vl is k vl,L_max Vehicle lateral position P lat is P relative to the right lane boundary R_small If it is less than the virtual load spring stiffness coefficient k vl is k vl,R_max In this way, the virtual load spring stiffness coefficient k vl The reason for the limitation is the virtual road load torque T rl This is to prevent the situation where the steering force becomes too large and the driver is unable to intervene in the steering.

[0063] Figure 6 shows the lateral position of the vehicle P lat Virtual load viscous damping coefficient c vl 10 is a graph showing an example of setting the

[0064] Vehicle lateral position P lat is the left lane boundary relative to the given P L_start or above or to the right lane boundary as specified P R_start If it is greater than or equal to the virtual load viscous damping coefficient c vl is a predetermined value c vl,start is set to

[0065] Vehicle lateral position P lat However, P L_start smaller than the given P L_small Above and P L_start If it is less than the virtual load viscous damping coefficient c vl is the vehicle lateral position P lat P L_start The smaller the value is from (the closer the vehicle reference position is to the left lane boundary), the vl,start From c vl,L_max The characteristic is set according to the increasing characteristics.

[0066] Vehicle lateral position P lat However, P R_start smaller than the given PR_small That's all. R_start If it is less than the virtual load viscous damping coefficient c vl is the vehicle lateral position P lat P R_start As the vehicle reference position gets closer to the right lane boundary, c vl,start From c vl,R_max The characteristic is set according to the increasing characteristics.

[0067] Vehicle lateral position P lat is P relative to the left lane boundary L_small If it is less than the virtual load viscous damping coefficient c vl is c vl,L_max Vehicle lateral position P lat is P relative to the right lane boundary R_small If it is less than the virtual load viscous damping coefficient c vl is c vl,R_max is set to

[0068] The equation of motion of the reference EPS model is expressed by the following equation (2).

[0069] J ref ·d 2 θ MD,cmd / dt 2 =T tb +T asst -k vl θ MD,cmd -c vl (dθ MD,cmd / dt) …(2) The manual steering command value generating unit 42 is T tb The torsion bar torque T detected by the torque sensor 12 is tb Substituting, T asst The assist torque command value T set by the assist torque command value setting unit 41 is asst By substituting and solving the differential equation (2), the manual steering command value θ MD,cmd Calculate the following.

[0070] In addition, the vehicle lateral position P lat The virtual load spring stiffness coefficient k corresponding to vlis, for example, the vehicle lateral position P lat and the vehicle lateral position P in Fig. 5 lat Virtual load spring stiffness coefficient k vl The vehicle lateral position P lat The virtual load viscous damping coefficient c corresponding to vl is, for example, the vehicle lateral position P lat and the vehicle lateral position P in Fig. 6 lat Virtual load viscous damping coefficient c vl is calculated based on the map in which the

[0071] In addition, the virtual road load torque T rl The virtual load spring stiffness coefficient k vl and the virtual load viscous damping coefficient c vl For example, the virtual road load torque T may be set depending on whether there is an adjacent lane to the lane, whether there is no adjacent lane to the lane, or whether there is a protective fence such as a guardrail to the lane. rl The virtual load spring stiffness coefficient k vl and the virtual load viscous damping coefficient c vl In this case, the information on the outside of the lane is provided from the host ECU 201 to the motor control ECU 202.

[0072] FIG. 7 is a block diagram showing the configuration of the angle control unit 44.

[0073] The angle control unit 44 calculates the integrated angle command value θ int,cmd Based on this, the integrated motor torque command value T mint,cmd The angle control unit 44 includes a low-pass filter (LPF) 51, a feedback control unit 52, a feedforward control unit 53, a disturbance torque estimating unit 54, a torque adding unit 55, a disturbance torque compensating unit 56, a first reduction ratio dividing unit 57, a reduction ratio multiplying unit 58, a rotation angle calculating unit 59, and a second reduction ratio dividing unit 60.

[0074] The reduction ratio multiplication unit 58 multiplies the motor torque command value T m,cmd is multiplied by the reduction ratio N of the reducer 19 to obtain the motor torque command value T m,cmd is the output shaft torque command value N·T acting on the output shaft 9 (worm wheel 21). m,cmd Convert to.

[0075] The rotation angle calculation unit 59 calculates the rotor rotation angle θ of the electric motor 18 based on the output signal of the rotation angle sensor 23. m The second reduction ratio division unit 60 calculates the rotor rotation angle θ calculated by the rotation angle calculation unit 59. m By dividing by the reduction ratio N, the rotor rotation angle θ m is converted into the rotation angle (actual steering angle) θ of the output shaft 9.

[0076] The low-pass filter 51 calculates the integrated angle command value θ int,cmd The integrated angle command value θ after low-pass filtering is intL,cmd is given to the feedback control section 52 and the feedforward control section 53.

[0077] The feedback control unit 52 converts the steering angle estimated value ^θ calculated by the disturbance torque estimating unit 54 into an integrated angle command value θ after low-pass filtering. intL,cmd The feedback control unit 52 includes an angle deviation calculation unit 52A and a PD control unit 52B. The angle deviation calculation unit 52A calculates an integrated angle command value θ intL,cmd and the deviation Δθ(=θ intL,cmd The angle deviation calculation unit 52A calculates the integrated angle command value θ intL,cmd and the deviation (θ intL,cmd -θ) may be calculated as the angle deviation Δθ.

[0078] The PD control unit 52B performs a PD calculation (proportional differential calculation) on the angle deviation Δθ calculated by the angle deviation calculation unit 52A, thereby obtaining a feedback control torque T fbCalculate the feedback control torque T fb is given to the torque adder 55.

[0079] The feedforward control unit 53 is provided to compensate for a delay in response due to the inertia of the electric power steering system 1, thereby improving the response of the control. The feedforward control unit 53 includes an angular acceleration calculation unit 53A and an inertia multiplication unit 53B. The angular acceleration calculation unit 53A calculates an integrated angle command value θ intL,cmd By differentiating twice, the target angular acceleration d 2 θ intL,cmd / dt 2 Calculate the following.

[0080] The inertia multiplication unit 53B multiplies the target angular acceleration d calculated by the angular acceleration calculation unit 53A by 2 θ intL,cmd / dt 2 is multiplied by the inertia J of the electric power steering system 1 to obtain the feedforward control torque T ff (=J·d 2 θ intL,cmd / dt 2 The inertia J can be calculated from, for example, a physical model (see FIG. 8) of the electric power steering system 1, which will be described later. The feedforward control torque T ff is given to the torque adder 55 as an inertia compensation value.

[0081] The torque adder 55 calculates the feedback control torque T fb to the feedforward control torque T ff By adding fb +T ff ) is calculated.

[0082] The disturbance torque estimating unit 54 is provided to estimate a nonlinear torque (disturbance torque: torque other than motor torque) that occurs as a disturbance in the plant (the object to be controlled by the electric motor 18). The disturbance torque estimating unit 54 estimates the output shaft torque command value N·T m,cmd and the actual steering angle θ, the disturbance torque (disturbance load) T lc, steering angle θ and steering angle differential value (angular velocity) dθ / dt are estimated. lc , the estimated values ​​of the steering angle θ and the steering angle differential (angular velocity) dθ / dt are respectively ^T lc , ^θ and d^θ / dt. The disturbance torque estimating unit 54 will be described in detail later.

[0083] The disturbance torque estimated value ^T calculated by the disturbance torque estimator 54 lc is given as a disturbance torque compensation value to the disturbance torque compensator 56. The steering angle estimated value ^θ calculated by the disturbance torque estimator 54 is given to the angle deviation calculator 52A.

[0084] The disturbance torque compensator 56 calculates the basic torque command value (T fb +T ff ) to the estimated disturbance torque ^T lc By subtracting sint,cmd (=T fb +T ff -^T lc ) is calculated. As a result, the integrated steering torque command value T sint,cmd (torque command value for output shaft 9) is obtained.

[0085] Integrated steering torque command value T sint,cmd is given to the first reduction ratio division unit 57. The first reduction ratio division unit 57 calculates the integrated steering torque command value T sint,cmd By dividing by the reduction ratio N, the integrated motor torque command value T mint,cmd This integrated motor torque command value T mint,cmd is given to the second weight multiplication unit 46 (see FIG. 2).

[0086] The disturbance torque estimation unit 54 will be described in detail. The disturbance torque estimation unit 54 uses, for example, a physical model 101 of the electric power steering system 1 shown in FIG. 8 to estimate the disturbance torque T lc , and a disturbance observer that estimates the steering angle θ and the angular velocity dθ / dt.

[0087] This physical model 101 includes a plant (an example of a motor-driven object) 102 including an output shaft 9 and a worm wheel 21 fixed to the output shaft 9. The plant 102 receives a torsion bar torque T tb is applied, and a road load torque T rl is given.

[0088] Furthermore, the plant 102 receives an output shaft torque command value N·T via a worm gear 20. m,cmd is given, and friction torque T f is given.

[0089] When the inertia of the plant 102 is J, the equation of motion for the inertia of the physical model 101 is expressed by the following equation (3).

[0090]

number

[0091] d 2 θ / dt 2 is the angular acceleration of the plant 102. N is the reduction ratio of the reducer 19. T lc represents a disturbance torque other than the motor torque applied to the plant 102. In this embodiment, the disturbance torque T lc is the torsion bar torque T tb and road load torque T rl and friction torque T f However, in reality, the disturbance torque T lc includes torques other than these.

[0092] The state equation for the physical model 101 in FIG. 8 is expressed by the following equation (4).

[0093]

number

[0094] In the above formula (4), x is a state variable vector, u1 is a known input vector, u2 is an unknown input vector, and y is an output vector (measured value). Also, in the above formula (4), A is a system matrix, B1 is a first input matrix, B2 is a second input matrix, C is an output matrix, and D is a direct feedthrough matrix.

[0095] The state equation is expanded to a system including the unknown input vector u2 as one of the states. The state equation of the expanded system (expanded state equation) is expressed by the following equation (5).

[0096]

number

[0097] In the formula (5), x e is the state variable vector of the extended system and is expressed by the following equation (6).

[0098]

number

[0099] In the formula (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.

[0100] From the extended state equation of the above formula (5), a disturbance observer (extended state observer) expressed by the following formula (7) is constructed.

[0101]

number

[0102] In equation (7), ^x e x e represents the estimated value of . Also, L is the observer gain. Also, ^y represents the estimated value of y. ^x eis expressed by the following equation (8).

[0103]

number

[0104] In equation (8), ^θ is the estimated value of θ, and ^T lc is T lc is an estimate of

[0105] The disturbance torque estimation unit 54 calculates the state variable vector ^x based on the equation (7). e Calculate the following.

[0106] FIG. 9 is a block diagram showing the configuration of the disturbance torque estimating section 54. As shown in FIG.

[0107] The disturbance torque estimation unit 54 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.

[0108] The output shaft torque command value N·T calculated by the reduction ratio multiplication unit 58 (see FIG. 7) m,cmd is given to the input vector input unit 71. The input vector input unit 71 outputs the input vector u1.

[0109] The output of the integrator 78 is the state variable vector ^x e (See equation (8) above.) At the start of calculation, the state variable vector ^x e The initial value is given as the state variable vector ^x e The initial value of is, for example, 0.

[0110] The system matrix multiplication unit 76 multiplies the state variable vector ^x e In the system matrix A e The output matrix multiplication unit 72 multiplies the state variable vector ^x e into the output matrix C e Multiply by.

[0111] The first adder 73 calculates the output (C e ^x e ) is subtracted from the output vector y. That is, the first adder 73 subtracts the output vector estimate ^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 (see equation (7) above).

[0112] 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 adder 77 multiplies the output (Be·u1) of the input matrix multiplier 75 by the output (A e ^x e ) and the output (L(y-^y)) of the gain multiplication unit 74, the differential value d^x of the state variable vector is obtained. e The integrator 78 calculates the output (d^x e / dt), the state variable vector ^x e The state variable vector output unit 79 calculates the state variable vector ^x e Based on this, the disturbance torque estimate ^T lc , the steering angle estimated value ^θ and the angular velocity estimated value d^θ / dt are calculated.

[0113] Unlike the extended state observer described above, a general disturbance observer consists of an inverse model of the plant and a low-pass filter. The equation of motion of the plant is expressed by equation (3) as described above. Therefore, the inverse model of the plant is expressed by the following equation (9).

[0114]

number

[0115] The input to a typical disturbance observer is J d 2θ / dt 2 and N.T. m,cmd and uses the second-order differential value of the actual steering angle θ, so it is significantly affected by noise from the rotation angle sensor 23. In contrast, the extended state observer of the above-described embodiment estimates the disturbance torque in an integral manner, so it is possible to reduce the influence of noise due to differentiation.

[0116] The disturbance torque estimating unit 54 may be a general disturbance observer that is configured from an inverse model of the plant and a low-pass filter.

[0117] FIG. 10 is a schematic diagram showing the configuration of the torque control unit 48.

[0118] The torque control unit 48 (see FIG. 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.

[0119] The motor current command value calculation unit 81 calculates the motor torque command value T m,cmd The torque constant K of the electric motor 18 t By dividing by, the motor current command value I m,cmd Calculate the following.

[0120] The current deviation calculation unit 82 calculates the motor current command value I obtained by the motor current command value calculation unit 81. m,cmd and the motor current I detected by the current detection circuit 32. m Deviation ΔI (=I m,cmd -I m ) is calculated.

[0121] The PI control unit 83 performs a PI calculation (proportional-plus-integral calculation) on the current deviation ΔI calculated by the current deviation calculation unit 82, thereby controlling the motor current I m The motor current command value I m,cmdThe PWM control unit 84 generates a PWM control signal with a duty ratio corresponding to the drive command value and supplies it to the drive circuit 31. As a result, power corresponding to the drive command value is supplied to the electric motor 18.

[0122] FIG. 11 is a flowchart showing the procedure of the weight setting process performed by the weight setting unit 49 in the driving assistance mode.

[0123] When the driving mode is changed to the driving assistance mode, the weight setting unit 49 sets the first weight W1 to 1 and the second weight W2 to 0 (step S1). As a result, the control mode of the electric motor 18 is changed to the assist torque command value T asst This results in a first control mode in which the electric motor 18 is driven and controlled only by the power supply.

[0124] When the driving mode is changed to the driving assistance mode, the host ECU 201 controls the automatic steering command value θ AD,cmd is set, and the automatic steering command value θ AD,cmd , mode signal S mode , left / right discrimination signal S LR and vehicle lateral position P lat is given to the motor control ECU 202.

[0125] Next, the weight setting unit 49 calculates the left / right discrimination signal S LR Based on this, it is determined whether the vehicle reference position is on the left side of the center of the lane (step S2).

[0126] If the vehicle reference position is on the left side of the center of the lane (step S2: YES), the weight setting unit 49 calculates the vehicle lateral position P lat P L_start (see FIGS. 5 and 6) (step S3).

[0127] P lat ≧P L_start If so (step S3: NO), the weight setting unit 49 returns to step S2.

[0128] In step S3, Plat <P L_start If it is determined that the first weight W1 is 0 (step S3: YES), the weight setting unit 49 sets the first weight W1 to 0 and the second weight W2 to 1 (step S4). At this time, it is preferable that the weight setting unit 49 gradually decreases the first weight W1 from 1 to 0 and gradually increases the second weight W2 from 0 to 1. The time taken to gradually decrease the first weight W1 from 1 to 0 (the time taken to gradually increase the second weight W2 from 0 to 1) may be, for example, about 0.1 seconds.

[0129] As a result, the control mode of the electric motor 18 is set to the integrated motor torque command value T mint,cmd The second control mode is set in which the electric motor 18 is driven and controlled by the following equation. While the first weight W1 is gradually decreasing (while the second weight W2 is gradually increasing), the assist torque command value W1·T after multiplication by the first weight is asst and the integrated motor torque command value w2·T after multiplication by the second weight mint,cmd The electric motor 18 is controlled based on the sum of

[0130] In the second control mode, the manual steering command value θ MD,cmd and the automatic steering command value θ AD,cmd The integrated angle command value θ int,cmd Since the electric motor 18 is controlled based on the manual steering command value θ MD,cmd The virtual road load torque T used in the calculation of rl The steering reaction force based on the above will be reflected.

[0131] Next, the weight setting unit 49 calculates the vehicle lateral position P lat P L_start greater than a given P L_return (see FIG. 12) (step S5). L_return is set to, for example, 80 cm. L_return is a threshold value used to return the control mode to the first control mode when the vehicle reference position is to the left of the center of the lane and the control mode is the second control mode.

[0132] P lat ≦PL_return If so (step S5: NO), the weight setting unit 49 returns to step S5.

[0133] In step S5, P lat >P L_return If it is determined that the first weight W1 is 1 and the second weight W2 is 0 (step S5: YES), the weight setting unit 49 sets the first weight W1 to 1 and the second weight W2 to 0 (step S6). At this time, it is preferable that the weight setting unit 49 gradually increases the first weight W1 from 0 to 1 and gradually decreases the second weight W2 from 1 to 0. The time taken to gradually increase the first weight W1 from 0 to 1 (the time taken to gradually decrease the second weight W2 from 1 to 0) may be, for example, about 0.1 seconds.

[0134] As a result, the control mode of the electric motor 18 becomes the first control mode. Note that while the first weight W1 is gradually increased (while the second weight W2 is gradually decreased), the assist torque command value W1·T after multiplication by the first weight asst and the integrated motor torque command value w2·T after multiplication by the second weight mint,cmd The electric motor 18 is controlled based on the sum of

[0135] In the first control mode, the manual steering command value θ MD,cmd The virtual road load torque T used in the calculation of rl The steering reaction force based on the steering angle is not reflected.

[0136] After the process of step S6 is performed, the weight setting unit 49 returns to step S2.

[0137] In step S2, if it is determined that the vehicle reference position is on the right side of the center of the lane (step S2: NO), the weight setting unit 49 calculates the vehicle lateral position P lat P R_start (see FIGS. 5 and 6) (step S7).

[0138] P lat ≧P R_start If so (step S7: NO), the weight setting unit 49 returns to step S2.

[0139] In step S7, P lat <P R_start If it is determined that the first weight W1 is 0 (step S7: YES), the weight setting unit 49 sets the first weight W1 to 0 and the second weight W2 to 1 (step S8). At this time, it is preferable that the weight setting unit 49 gradually decreases the first weight W1 from 1 to 0 and gradually increases the second weight W2 from 0 to 1.

[0140] As a result, the control mode of the electric motor 18 is set to the second control mode. In the second control mode, the virtual road load torque T rl The steering reaction force based on the above will be reflected.

[0141] Next, the weight setting unit 49 calculates the vehicle lateral position P lat P R_start greater than a given P R_return (see FIG. 12) (step S9). R_return is set to, for example, 90 cm. R_return is a threshold value used to return the control mode to the first control mode when the vehicle reference position is to the right of the center of the lane and the control mode is the second control mode.

[0142] P lat ≦P R_return If so (step S9: NO), the weight setting unit 49 returns to step S9.

[0143] In step S9, P lat >P R_return If it is determined that the first weight W1 is 1 and the second weight W2 is 0 (step S9: YES), the weight setting unit 49 sets the first weight W1 to 1 and the second weight W2 to 0 (step S10). At this time, it is preferable that the weight setting unit 49 gradually increases the first weight W1 from 0 to 1 and gradually decreases the second weight W2 from 1 to 0.

[0144] As a result, the control mode of the electric motor 18 is set to the first control mode. In the first control mode, the virtual road load torque T rlThe steering reaction force based on the steering angle is not reflected.

[0145] After the process of step S10 is performed, the weight setting unit 49 returns to step S2.

[0146] When the driving mode is the normal mode, the weight setting unit 49 sets the first weight W1 to 1 and the second weight W2 to 0. Therefore, in the normal mode, the assist torque command value T asst The electric motor 18 is controlled based only on the above.

[0147] Figure 12 shows the lateral position of the vehicle P lat and the virtual road load torque T calculated based on equation (1) rl Absolute value of |T rl 12 is a graph showing an example of the relationship between θ MD,cmd and dθ MD,cmd Vehicle lateral position P when / dt is assumed to be constant lat and the absolute value of the virtual road load torque |T rl | indicates the relationship.

[0148] In Fig. 12, the virtual road load torque T rl The virtual load spring stiffness coefficient k vl and the virtual load viscous damping coefficient c vl is set.

[0149] Vehicle lateral position P lat is P relative to the left lane boundary L_start or above, or P R_start In the above cases, the virtual load spring composition coefficient k vl is k vl,start and the virtual load viscous damping coefficient c vl is c vl,start Therefore, the absolute value of the virtual road load torque |T rl | is a constant value.

[0150] Vehicle lateral position P lat However, P L_small Above and P L_start If it is less than the absolute value of the virtual road load torque |T rl | is the vehicle lateral position P lat P L_start The smaller the |T| becomes (the closer the vehicle reference position is to the left lane boundary), the larger the |T| becomes. rl | increases linearly, but |T rl may be made to increase nonlinearly.

[0151] Vehicle lateral position P lat P L_small When the absolute value of the virtual road load torque |T rl | is the vehicle lateral position P lat P L_small The absolute value of the virtual road load torque when |T rl | is fixed.

[0152] Vehicle lateral position P lat However, P R_small Above and P R_start If it is less than the absolute value of the virtual road load torque |T rl | is the vehicle lateral position P lat P R_start The smaller the |T| becomes (the closer the vehicle reference position is to the left lane boundary), the larger the |T| becomes. rl | increases linearly, but |T rl may be made to increase nonlinearly.

[0153] Vehicle lateral position P lat P R_small When the virtual road load torque T rl Absolute value of |T rl | is the vehicle lateral position P lat P R_small The absolute value of the virtual road load torque when |T rl | is fixed.

[0154] In the example of FIG. 12, the vehicle lateral position P lat PL_start or P R_start The absolute value of the virtual road load torque |T rl The virtual load spring stiffness coefficient k is set so that | increases in the order of when there is an adjacent lane, when there is no adjacent lane, and when there is a safety fence. vl and the virtual load viscous damping coefficient c vl is set.

[0155] Fig. 13 shows the virtual road load torque T rl 10 is a schematic diagram for explaining a steering reaction force generated based on the steering angle. FIG.

[0156] At time t0, the control mode is the first mode, and the vehicle reference position is in the center of the lane. Since the control mode is the first control mode, W1=1, W2=0, and the manual steering command value θ MD,cmd The virtual road load torque T used in the calculation of rl The steering reaction force based on is 0.

[0157] Immediately after time t0, the driver steers the vehicle to the right, causing the vehicle to start moving to the right. Then, at time t1, the vehicle lateral position P lat P R_start When W1 reaches t2, W1 is gradually decreased and W2 is gradually increased, and at time t2, W1=0 and W2=1. That is, the control mode becomes the second control mode.

[0158] From time t0 to time t1, the manual steering command value θ MD,cmd The virtual road load torque T used in the calculation of rl is 0, but from time t1 to time t2, the virtual road load torque T rl Since a part of the steering reaction force based on the virtual road load torque T is reflected, the steering reaction force gradually increases. Then, from time t2, the control mode becomes the second control mode, and the virtual road load torque T rl The steering reaction force based on the steering angle becomes even larger.

[0159] Then, when the vehicle reference position reaches the right lane boundary (time t3), the steering reaction force reaches the maximum reaction force value. When the driver feels the steering reaction force and stops steering to the right, the vehicle moves toward the center of the lane. Then, when the vehicle reference position enters the lane center side beyond the right lane boundary (time t4), the virtual road load torque T rl The steering reaction force based on the vehicle lateral position P lat P R_start When it reaches (time t5), the virtual road load torque T rl The steering reaction force based on this becomes a constant value.

[0160] After this, the vehicle lateral position P lat P R_return (time t6), W1 is gradually increased and W2 is gradually decreased, and at time t7, W1 = 1 and W2 = 0. In other words, the control mode switches to the first control mode. As can be seen from FIG. 13, in the period from time t4 to time t5, the steering reaction force characteristic becomes a characteristic (first characteristic) in which the reduction rate of the steering reaction force is large, and in the period from time t5 to time t6, which will be described later, the steering reaction force characteristic becomes a characteristic (second characteristic) in which the reduction rate of the steering reaction force is small. This makes it possible to stabilize the vehicle behavior when the vehicle returns to the center of the lane.

[0161] 13, the reduction rate of the steering reaction force in the second characteristic is 0 (i.e., the steering reaction force is constant), but the reduction rate of the steering reaction force in the second characteristic may be a value other than 0 as long as it is lower than the reduction rate of the steering reaction force in the first characteristic. In this embodiment, by setting the reduction rate of the steering reaction force in the second characteristic to 0, it is possible to reliably stabilize the vehicle behavior when the vehicle returns to the center of the lane.

[0162] From time t6 to time t7, the virtual road load torque T rl Since a part of the steering reaction force based on the virtual road load torque T is reflected, the steering reaction force gradually decreases. rl The steering reaction force based on this is 0.

[0163] In the above-described embodiment, the manual steering command value generating unit 42 can design the steering reaction force independently of the steering angle control for the assist control and the driving assistance.

[0164] Furthermore, in the above-described embodiment, the driver can feel the reaction force according to the lateral position of the vehicle as a steering torque, which improves the effectiveness of preventing departure from the lane.

[0165] In the above-described embodiment, the first vehicle lateral position for switching the first weight W1 from 1 to 0 (the second weight W1 from 0 to 1) and the second vehicle lateral position for switching the first weight W1 from 0 to 1 (the second weight W1 from 1 to 0) are set to different positions. Specifically, the second vehicle lateral position is set closer to the lane center than the first vehicle lateral position. This makes it possible to both generate a reaction force to the driver when heading in the lane departure direction and stabilize the vehicle behavior when returning to the lane center.

[0166] In other words, if the second vehicle lateral position is set to the same position as the first vehicle lateral position, the control mode will be switched from the second control mode to the first control mode when a large steering reaction force is acting, which may cause the vehicle behavior to become unstable.

[0167] Furthermore, in the above-described embodiment, the driver can intuitively recognize the degree of danger according to the environment outside the current driving lane (presence or absence of adjacent lanes, presence or absence of guardrails, etc.) through the steering wheel.

[0168] A modified example of the procedure of the weight setting process performed by the weight setting unit 49 in the driving assistance mode (a modified example of the weight setting unit 49) will be described below.

[0169] [First Modification of Weight Setting Unit 49] In the first variant, the first vehicle lateral position for switching the first weight W1 from 1 to 0 (the second weight W1 from 0 to 1) and the second vehicle lateral position for switching the first weight W1 from 0 to 1 (the second weight W1 from 1 to 0) are set to the same position.

[0170] Here, P is the first vehicle position and P is the second vehicle position when the vehicle is on the left side of the lane center. L_return is set, and P is the first and second vehicle positions when the vehicle is on the right side of the lane center. R_return is assumed to be set.

[0171] In this case, the procedure of the weight setting process performed by the weight setting unit 49 in the driving support mode is almost the same as the procedure shown in Fig. 11. However, P in step S3 of Fig. 11 lat <P L_start The condition is P lat <P L_return In addition, the condition P in step S7 of FIG. lat <P R_start The condition is P lat <P R_return The rest of the procedure is the same as that in Figure 11.

[0172] FIG. 14 shows the virtual road load torque T rl 10 is a schematic diagram for explaining a steering reaction force generated based on the steering angle. FIG.

[0173] At time t0, the control mode is the first mode, and the vehicle reference position is in the center of the lane. Since the control mode is the first control mode, W1=1, W2=0, and the manual steering command value θ MD,cmd The virtual road load torque T used in the calculation of rl The steering reaction force based on is 0.

[0174] Immediately after time t0, the driver steers the vehicle to the right, causing the vehicle to start moving to the right. Then, at time t1, the vehicle lateral position P lat P R_return When the vehicle crosses the boundary of the right lane, W1 is gradually decreased and W2 is gradually increased, and at time t2, W1=0 and W2=1. That is, the control mode changes to the second control mode.

[0175] From time t0 to time t1, the manual steering command value θ MD,cmd The virtual road load torque T used in the calculation of rl is 0, but from time t1 to time t2, the virtual road load torque T rl Since a part of the steering reaction force based on the virtual road load torque T is reflected, the steering reaction force gradually increases. Then, from time t2, the control mode becomes the second control mode, and the virtual road load torque T rl The steering reaction force based on the steering angle becomes even larger.

[0176] Then, when the vehicle reference position reaches the right lane boundary (time t3), the steering reaction force reaches the maximum reaction force value. When the driver feels the steering reaction force and stops steering to the right, the vehicle moves toward the center of the lane. Then, when the vehicle reference position enters the lane center side beyond the right lane boundary (time t4), the virtual road load torque T rl The steering reaction force based on the vehicle lateral position P lat P R_start When it reaches (time t5), the virtual road load torque T rl The steering reaction force based on this becomes a constant value.

[0177] After this, at time t6, the vehicle lateral position P lat P R_return When the vehicle crosses the lane center, W1 gradually increases and W2 gradually decreases, and at time t7, W1 = 1 and W2 = 0. In other words, the control mode switches to the first control mode. As can be seen from FIG. 14, in the period from time t4 to time t5, the steering reaction force characteristic becomes a characteristic (first characteristic) in which the reduction rate of the steering reaction force is large, and in the period from time t5 to time t6 (described later), the steering reaction force characteristic becomes a characteristic (second characteristic) in which the reduction rate of the steering reaction force is small. This makes it possible to stabilize the vehicle behavior when the vehicle returns to the lane center.

[0178] In Fig. 14, the reduction rate of the steering reaction force in the second characteristic is 0 (i.e., the steering reaction force is constant), but the reduction rate of the steering reaction force in the second characteristic may be a value other than 0 as long as it is lower than the reduction rate of the steering reaction force in the first characteristic. In this embodiment, by setting the reduction rate of the steering reaction force in the second characteristic to 0, it is possible to reliably stabilize the vehicle behavior when the vehicle returns to the center of the lane.

[0179] From time t6 to time t7, the virtual road load torque T rl Since a part of the steering reaction force based on the virtual road load torque T is reflected, the steering reaction force gradually decreases. rl The steering reaction force based on this is 0.

[0180] [Second Modification of Weight Setting Unit 49] Fig. 15 is a block diagram showing the electrical configuration of a motor control ECU 0202 including a weight setting unit 49 according to a second modification. In Fig. 15, parts corresponding to those in Fig. 2 described above are denoted by the same reference numerals as in Fig. 2.

[0181] 15 is provided with a hands-on / off determination unit 50. The hands-on / off determination unit 50 determines whether the driver is in a gripping state (hands-on) where the driver is gripping the steering wheel 2, or in a hands-off state (hands-off) where the driver is not gripping the steering wheel 2. The determination result of the hands-on / off determination unit 50 is provided to a weight setting unit 49.

[0182] The hands-on / off determination unit 50 determines, for example, the torsion bar torque T tb and the actual steering angle θ or rotor rotation angle θ mThe hands-on / off determination unit 50 may estimate the driver torque, which is the torque applied to the steering wheel 2 by the driver, based on the estimated value, and determine the state as being gripped if the driver torque is equal to or greater than a predetermined threshold, and determine the state as being hands-off if the driver torque remains below the threshold for a predetermined period of time. In this case, the state is determined as being gripped after the driver torque changes from a state equal to or greater than the threshold to a state below the threshold until the state as being hands-off is determined. As such a hands-on / off determination unit 50, for example, a "steering wheel operation state determination unit" described in Japanese Patent Application Laid-Open No. 2017-114324, Japanese Patent Application Laid-Open No. 2018-165156, Japanese Patent Application Laid-Open No. 2020-142703, Japanese Patent Application Laid-Open No. 2020-59361, Japanese Patent Application Laid-Open No. 2020-59362, etc. may be used.

[0183] The hands-on / off determination unit 50 determines, for example, the torsion bar torque T tb is equal to or greater than a predetermined threshold, it is determined that the gripping state is established, and the torsion bar torque T tb The torsion bar torque T may be determined to be in a hands-off state when the state where the torsion bar torque T is less than the threshold value continues for a predetermined time or more. tb After the value of the threshold value changes from a value equal to or greater than the threshold value to a value less than the threshold value, the state is determined to be the grip state until the state is determined to be the no-hand state.

[0184] FIG. 16 is a flowchart showing the procedure of the weight setting process performed by the weight setting unit 49 according to the second modification in the driving assistance mode.

[0185] When the driving mode is changed to the driving assistance mode, the weight setting unit 49 sets the first weight W1 to 1 and the second weight W2 to 0 (step S11). As a result, the control mode of the electric motor 18 is changed to the assist torque command value T asst This results in a first control mode in which the electric motor 18 is driven and controlled only by the power supply.

[0186] When the driving mode is changed to the driving assistance mode, the host ECU 201 controls the automatic steering command value θ AD,cmd is set, and the automatic steering command value θ AD,cmd , mode signal Smode , left / right discrimination signal S LR and vehicle lateral position P lat is given to the motor control ECU 202.

[0187] Next, the weight setting unit 49 calculates the left / right discrimination signal S LR Based on this, it is determined whether the vehicle reference position is on the left side of the center of the lane (step S12).

[0188] If the vehicle reference position is on the left side of the center of the lane (step S12: YES), the weight setting unit 49 calculates the vehicle lateral position P lat P L_start (see FIGS. 5 and 6) (step S13).

[0189] P lat ≧P L_start If so (step S13: NO), the weight setting unit 49 returns to step S12.

[0190] In step S13, P lat <P L_start If it is determined that the first weight W1 is 0 (step S13: YES), the weight setting unit 49 sets the first weight W1 to 0 and the second weight W2 to 1 (step S14). At this time, it is preferable that the weight setting unit 49 gradually decreases the first weight W1 from 1 to 0 and gradually increases the second weight W2 from 0 to 1. The time taken to gradually decrease the first weight W1 from 1 to 0 (the time taken to gradually increase the second weight W2 from 0 to 1) may be, for example, about 0.1 seconds.

[0191] As a result, the control mode of the electric motor 18 is set to the integrated motor torque command value T mint,cmd The second control mode is set in which the electric motor 18 is driven and controlled by the following equation. While the first weight W1 is gradually decreasing (while the second weight W2 is gradually increasing), the assist torque command value W1·T after multiplication by the first weight is asst and the integrated motor torque command value w2·T after multiplication by the second weight mint,cmd The electric motor 18 is controlled based on the sum of

[0192] In the second control mode, the manual steering command value θ MD,cmd and the automatic steering command value θ AD,cmd The integrated angle command value θ int,cmd Since the electric motor 18 is controlled based on the manual steering command value θ MD,cmd The virtual road load torque T used in the calculation of rl The steering reaction force based on the above will be reflected.

[0193] Next, the weight setting unit 49 calculates the vehicle lateral position P lat P L_start greater than a given P L_return (See FIG. 12) or the vehicle lateral position P lat P L_start It is determined whether or not the second condition is satisfied, that is, whether the distance is greater than the predetermined distance and the determination result of the hands-on / off determination unit 50 indicates the gripping state (step S15). L_return is set to, for example, 80 cm.

[0194] If neither the first condition nor the second condition is satisfied (step S15: NO), the weight setting unit 49 returns to step S15.

[0195] If it is determined in step S15 that either the first condition or the second condition is satisfied (step S15: YES), the weight setting unit 49 sets the first weight W1 to 1 and the second weight W2 to 0 (step S16). At this time, it is preferable that the weight setting unit 49 gradually increases the first weight W1 from 0 to 1 and gradually decreases the second weight W2 from 1 to 0. The time taken to gradually increase the first weight W1 from 0 to 1 (the time taken to gradually decrease the second weight W2 from 1 to 0) may be, for example, about 0.1 seconds.

[0196] As a result, the control mode of the electric motor 18 becomes the first control mode. Note that while the first weight W1 is gradually increased (while the second weight W2 is gradually decreased), the assist torque command value W1·T after multiplication by the first weight asst and the integrated motor torque command value w2·T after multiplication by the second weight mint,cmdThe electric motor 18 is controlled based on the sum of

[0197] In the first control mode, the manual steering command value θ MD,cmd The virtual road load torque T used in the calculation of rl The steering reaction force based on the steering angle is not reflected.

[0198] After the process of step S16 is performed, the weight setting unit 49 returns to step S12.

[0199] In step S12, when it is determined that the vehicle reference position is on the right side of the center of the lane (step S12: NO), the weight setting unit 49 calculates the vehicle lateral position P lat P R_start (see FIGS. 5 and 6) (step S17).

[0200] P lat ≧P R_start If so (step S17: NO), the weight setting unit 49 returns to step S12.

[0201] In step S17, P lat <P R_start If it is determined that the first weight W1 is 0 (step S17: YES), the weight setting unit 49 sets the first weight W1 to 0 and the second weight W2 to 1 (step S18). At this time, it is preferable that the weight setting unit 49 gradually decreases the first weight W1 from 1 to 0 and gradually increases the second weight W2 from 0 to 1.

[0202] As a result, the control mode of the electric motor 18 is set to the second control mode. In the second control mode, the virtual road load torque T rl The steering reaction force based on the above will be reflected.

[0203] Next, the weight setting unit 49 calculates the vehicle lateral position P lat P R_start greater than a given P R_return (See Figure 12) or the vehicle lateral position P lat P R_startIt is determined whether or not the fourth condition is satisfied, that is, the position is greater than the position where the hand is held and the determination result of the hands-on / off determination unit 50 indicates the gripping state (step S19). R_return is set to, for example, 90 cm.

[0204] If neither the third nor the fourth condition is satisfied (step S19: NO), the weight setting unit 49 returns to step S19.

[0205] In step S19, if it is determined that either the third condition or the fourth condition is satisfied (step S19: YES), the weight setting unit 49 sets the first weight W1 to 1 and the second weight W2 to 0 (step S20). At this time, it is preferable that the weight setting unit 49 gradually increases the first weight W1 from 0 to 1 and gradually decreases the second weight W2 from 1 to 0.

[0206] As a result, the control mode of the electric motor 18 is set to the first control mode. In the first control mode, the virtual road load torque T rl The steering reaction force based on the steering angle is not reflected.

[0207] After the process of step S20 is performed, the weight setting unit 49 returns to step S12.

[0208] FIG. 17 shows the virtual road load torque T rl 10 is a schematic diagram for explaining a steering reaction force generated based on the steering angle. FIG.

[0209] The operation from time t0 to time t5 in Fig. 17 is the same as that in Fig. 13. At time t4, the vehicle starts to move from the right lane boundary to the center of the lane, and the vehicle lateral position P lat P R_start When it reaches (time t5), the virtual road load torque T rl The steering reaction force based on this becomes a constant value.

[0210] After this, the vehicle lateral position P lat P R_returnIf the hands-on / off state result becomes the gripped state (time t8) before the vehicle crosses the center of the lane, the fourth condition of step S19 in Fig. 16 is satisfied. As a result, W1 is gradually increased and W2 is gradually decreased, and at time t9, W1 = 1 and W2 = 0. In other words, the control mode becomes the first control mode.

[0211] In other words, the vehicle lateral position P lat P R_start When the vehicle moves closer to the center of the lane than the vehicle lateral position P lat P R_return The second control mode can be switched to the first control mode even if the vehicle does not cross the lane center line.

[0212] From time t8 to time t9, the virtual road load torque T rl Since a part of the steering reaction force based on the virtual road load torque T is reflected, the steering reaction force gradually decreases. rl The steering reaction force based on this is 0.

[0213] [Modification of the manual steering command value generating unit 42] Below, a modified example of the manual steering command value generating unit 42 will be described.

[0214] In the above embodiment, the virtual load spring stiffness coefficient k vl and the virtual load viscous damping coefficient c vl is the vehicle lateral position P lat It is set corresponding to.

[0215] In this modified example of the manual steering command value generating unit 42, the virtual load spring stiffness coefficient k vl and the virtual load viscous damping coefficient c vl is the vehicle lateral position P lat and heading angle θ vh The heading angle θ is set corresponding to vh As shown in Fig. 18, the angle (0°≦θ vh<180°), which is positive when the vehicle is heading from the center of the lane toward the lane boundary, and negative when the vehicle is heading toward the center of the lane. When the vehicle's direction of travel is parallel to the lane center line, the heading angle θ vh will be 0 degrees.

[0216] Heading angle θ vh 1 and 2, is given from the host ECU 201 to the manual steering command value generating unit 42 in the motor control ECU 202. In addition, when the weight setting process shown in FIG. 24 or the weight setting process shown in FIG. 26 is performed by the weight setting unit 49, the heading angle θ vh is also given to the weight setting unit 49.

[0217] In this modified example of the manual steering command value generating unit 42, the rotation angle of the lower column in FIG. 4 is converted into a manual steering command value θ MD,cmd Then, the road load torque (virtual road load torque) T rl is the virtual load spring stiffness coefficient k vl , virtual load viscous damping coefficient c vl and manual steering command value θ MD,cmd Using this, it is expressed by the following equation (10).

[0218] T rl =-k vl θ MD,cmd -c vl (dθ MD,cmd / dt) …(10) However, k vl =k vl (P lat ,θ vh ),c vl =c vl (P lat ,θ vh ) As shown in the above equation (10), the virtual load spring stiffness coefficient k vl and the virtual load viscous damping coefficient c vl is the vehicle lateral position P lat and heading angle θ vh It is set corresponding to.

[0219] Figure 19 shows the lateral position of the vehicle P lat Virtual load spring stiffness coefficient k vl 10 is a graph showing an example of setting the

[0220] In Figure 19, the heading angle θ vh When the heading angle is 0[deg], vh is 2[deg], and the heading angle θ vh An example where the angle is -0.5[deg] is shown.

[0221] The subscript L of the symbols in Fig. 19 indicates that the symbol applies when the vehicle reference position is to the left of the center of the lane, and the subscript R indicates that the symbol applies when the vehicle reference position is to the right of the center of the lane. The same applies to Fig. 22, which will be described later.

[0222] P in FIG. 19 and FIGS. 20 to 23 described later L_return , P L_start , P L_return and P R_start are the P in Figure 12, respectively. L_return , P L_start , P L_return and P R_start 19 and 20 to 23 described later, or may be set at a different position. L_return , P L_start , P L_return and P R_start are the P in Figure 12, respectively. L_return , P L_start , P L_return and P R_start It is assumed to be set in the same position as

[0223] Vehicle lateral position P lat is the left lane boundary. L_return The designated P is closer to the center of the lane than L1 or above or to the right lane boundary R_return The designated P is closer to the center of the lane than R1 If it is greater than or equal to the virtual load spring stiffness coefficient k vlis set to 0. P L1 and P R1 is set to, for example, about 110 cm.

[0224] Vehicle lateral position P lat is on the left side of the lane center, and the vehicle's lateral position P lat is 0 or more and P L1 If it is less than the virtual load spring stiffness coefficient k vl is the vehicle lateral position P lat and heading angle θ vh and depending on the vehicle lateral position P lat P L1 The virtual load spring stiffness coefficient k is set according to the characteristic that it gradually increases as it decreases (as the vehicle reference position approaches the left lane boundary). vl increases linearly, but the virtual load spring stiffness coefficient k vl may increase nonlinearly.

[0225] Virtual load spring stiffness coefficient k in this section vl is the heading angle θ vh When the heading angle θ is positive (when the vehicle is moving toward the left lane boundary), vh On the other hand, the larger the heading angle θ vh When is negative (the vehicle is moving toward the center of the lane), the virtual load spring stiffness coefficient k vl is the heading angle θ vh The larger the absolute value of , the smaller it becomes.

[0226] Vehicle lateral position P lat is on the right side of the lane center, and the vehicle's lateral position P lat is 0 or more and P R2 If it is less than the virtual load spring stiffness coefficient k vl is the vehicle lateral position P lat and heading angle θ vh and depending on the vehicle lateral position P lat P R1 The virtual load spring stiffness coefficient k is set according to the characteristic that it gradually increases as it decreases (as the vehicle reference position approaches the right lane boundary). vlincreases linearly, but the virtual load spring stiffness coefficient k vl may increase nonlinearly.

[0227] Virtual load spring stiffness coefficient k in this section vl is the heading angle θ vh When the heading angle θ is positive (when the vehicle is moving toward the right lane boundary), vh On the other hand, the larger the heading angle θ vh When is negative (the vehicle is moving towards the left lane boundary), the virtual load spring stiffness coefficient k vl is the heading angle θ vh The larger the absolute value of , the smaller it becomes.

[0228] An example of a method for setting the virtual load spring stiffness coefficient characteristic as shown in FIG. 19 will be described.

[0229] First, the heading angle θ vh When the vehicle lateral position P is 0[deg] lat Virtual load spring stiffness coefficient k vl The characteristics of the spring stiffness coefficient k vl The spring stiffness coefficient k is set. vl An example of the basic characteristics is shown in Figure 20.

[0230] Next, the heading angle θ vh Set the weight (heading weight) for the heading angle θ vh An example of the weighting characteristics for the heading angle θ vh For example, in FIG. 21, the weighting characteristics for the heading angle θ vh Although the weighting characteristic increases and decreases linearly with the increase and decrease of , it may also increase and decrease nonlinearly. Also, the weighting may be set to a constant value for a specific angle range. In FIG. 21, in order to suppress changes in the steering reaction force when the traveling direction of the vehicle is in the departure direction and is approximately parallel to the lane center line, the weighting characteristic is set to a constant value for the heading angle θ within an angle range from 0 [deg] to 1 [deg]. vh The gain is set to 1 for

[0231] The spring stiffness coefficient k in Figure 20 vl The basic characteristics of the head angle θ in Figure 21 vh Based on the weight characteristics for the heading angle θ vh For each, the vehicle lateral position P lat Virtual load spring stiffness coefficient k vl For example, the heading angle θ vh The characteristics for 2[deg] are the spring stiffness coefficient k vl The basic characteristics are set by multiplying them by 1.25, which is the weight for 2[deg].

[0232] Figure 22 shows the lateral position of the vehicle P lat Virtual load viscous damping coefficient c vl 10 is a graph showing an example of setting the

[0233] Figure 22 shows the heading angle θ vh When the heading angle is 0[deg], vh is 2[deg], and the heading angle θ vh An example where the angle is -0.5[deg] is shown.

[0234] Vehicle lateral position P lat Virtual load viscous damping coefficient c vl The characteristics of the vehicle lateral position P lat Virtual load spring stiffness coefficient k vl The characteristics are similar to those of the lateral position P lat Virtual load viscous damping coefficient c vl The characteristics of the vehicle lateral position P lat Virtual load spring stiffness coefficient k vl It is set in a similar way to how the properties of

[0235] As in the above-described embodiment, the manual steering command value generating unit 42 calculates the manual steering command value θ MD,cmd where the virtual load spring stiffness coefficient k vl and the virtual load viscous damping coefficient c vlAs shown in equation (10), the vehicle lateral position P lat and heading angle θ vh The virtual load spring stiffness coefficient k vl and the virtual load viscous damping coefficient c vl is used.

[0236] Vehicle lateral position P lat and heading angle θ vh The virtual load spring stiffness coefficient k corresponding to vl is, for example, the vehicle lateral position P lat and multiple heading angles θ vh Vehicle lateral position P lat Virtual load spring stiffness coefficient k vl The vehicle lateral position P lat and heading angle θ vh The virtual load viscous damping coefficient c corresponding to vl is, for example, the vehicle lateral position P lat and multiple heading angles θ vh Vehicle lateral position P lat Virtual load viscous damping coefficient c vl is calculated based on the stored map (see the graph in FIG. 22).

[0237] Figure 23 shows the lateral position of the vehicle P lat and the road load torque T calculated based on Equation (10) rl Absolute value of |T rl 10 is a graph showing an example of the relationship between |

[0238] In Figure 23, the heading angle θ vh When the heading angle is 0[deg], vh is 2[deg], and the heading angle θ vh An example where the angle is -0.5[deg] is shown.

[0239] Vehicle lateral position P lat is P relative to the left lane boundary L1or above, or P R1 In the above cases, the virtual load spring composition coefficient k vl and the virtual load viscous damping coefficient c vl is 0, so the absolute value of the virtual road load torque |T rl | becomes 0.

[0240] Vehicle lateral position P lat is on the left side of the lane center, and the vehicle's lateral position P lat is 0 or more and P L1 If it is less than the absolute value of the virtual road load torque |T rl | is the vehicle lateral position P lat P L1 The smaller the |T| becomes (the closer the vehicle reference position is to the left lane boundary), the larger the |T| becomes. rl | increases nonlinearly.

[0241] Vehicle lateral position P lat is on the right side of the lane center, and the vehicle's lateral position P lat is 0 or more and P R1 If it is less than the absolute value of the virtual road load torque |T rl | is the vehicle lateral position P lat P R1 The smaller the |T| becomes (the closer the vehicle reference position is to the left lane boundary), the larger the |T| becomes. rl | increases nonlinearly.

[0242] Next, the virtual load spring stiffness coefficient k vl and the virtual load viscous damping coefficient c vl is the vehicle lateral position P lat and heading angle θ vh The operation of the weight setting unit 49 when the weights are set in accordance with the above will be described.

[0243] As shown in Figure 23, P L1 and P L_strt Between L_return is set, and P R1 and P R_strt Between R_returnis set, the weight setting unit 49 can perform the weight setting process according to the procedure in Fig. 9 or the procedure in Fig. 16. Furthermore, the weight setting unit 49 can perform the weight setting process described in the first modified example of the weight setting unit 49 (a modified example in which the first vehicle lateral position and the second vehicle lateral position are the same).

[0244] Virtual load spring stiffness coefficient k vl and the virtual load viscous damping coefficient c vl is the vehicle lateral position P lat and heading angle θ vh In the following, for the sake of convenience, the weight setting unit 49 may perform the weight setting process in accordance with the P L_return and P L_start The corresponding positions are P L2 and P L3 In addition, P in Figs. R_return and P R_start The corresponding positions are P R2 and P R3 This is expressed as:

[0245] [Third Modification of Weighting Setting Unit 49] In the third modified example, when the vehicle is on the left side of the lane center, the first vehicle lateral position for switching the first weight W1 from 1 to 0 (the second weight W1 from 0 to 1) is set to P L2 (P in Figure 12 L_return (the position corresponding to the L1 The first vehicle lateral position when the vehicle is on the left side of the lane center is set within the following range. L1 In addition, when the vehicle is on the left side of the lane center, the second vehicle lateral position for switching the first weight W1 from 0 to 1 (the second weight W1 from 1 to 0) is P L2 is set to

[0246] When the vehicle is on the right side of the lane center, the first vehicle lateral position for switching the first weight W1 from 1 to 0 (the second weight W1 from 0 to 1) is P R2 (P in Figure 12 R_return (the position corresponding to the R1 In this case, the first vehicle lateral position when the vehicle is on the right side of the lane center is set within the range P R1 When the vehicle is on the right side of the lane center, the second vehicle lateral position for switching the first weight W1 from 0 to 1 (the second weight W1 from 1 to 0) is set to P R2 is set to

[0247] FIG. 24 is a flowchart showing the procedure of the weight setting process performed by the weight setting unit 49 according to the third modified example in the driving assistance mode.

[0248] When the driving mode is changed to the driving assistance mode, the weight setting unit 49 sets the first weight W1 to 1 and the second weight W2 to 0 (step S21). As a result, the control mode of the electric motor 18 is changed to the assist torque command value T asst This results in a first control mode in which the electric motor 18 is driven and controlled only by the power supply.

[0249] When the driving mode is changed to the driving assistance mode, the host ECU 201 controls the automatic steering command value θ AD,cmd is set, and the automatic steering command value θ AD,cmd , mode signal S mode , left / right discrimination signal S LR and vehicle lateral position P lat is given to the motor control ECU 202.

[0250] Next, the weight setting unit 49 calculates the left / right discrimination signal S LR Based on this, it is determined whether the vehicle reference position is on the left side of the center of the lane (step S22).

[0251] If the vehicle reference position is on the left side of the lane center (step S22: YES), the weight setting unit 49 calculates the vehicle lateral position P lat P L1(See Figure 25) and the heading angle θ vh It is determined whether or not the fifth condition that P is greater than 0 is satisfied (step S23). L1 is set to, for example, 110 cm.

[0252] If the fifth condition is not met (step S23: NO), the weight setting unit 49 returns to step S22.

[0253] If it is determined in step S23 that the fifth condition is satisfied (step S23: YES), the weight setting unit 49 sets the first weight W1 to 0 and the second weight W2 to 1 (step S24). At this time, it is preferable that the weight setting unit 49 gradually decreases the first weight W1 from 1 to 0 and gradually increases the second weight W2 from 0 to 1. The time taken to gradually decrease the first weight W1 from 1 to 0 (the time taken to gradually increase the second weight W2 from 0 to 1) may be, for example, about 0.1 seconds.

[0254] As a result, the control mode of the electric motor 18 is set to the integrated motor torque command value T mint,cmd The second control mode is set in which the electric motor 18 is driven and controlled by the following equation. While the first weight W1 is gradually decreasing (while the second weight W2 is gradually increasing), the assist torque command value W1·T after multiplication by the first weight is asst and the integrated motor torque command value w2·T after multiplication by the second weight mint,cmd The electric motor 18 is controlled based on the sum of

[0255] In the second control mode, the manual steering command value θ MD,cmd and the automatic steering command value θ AD,cmd The integrated angle command value θ int,cmd Since the electric motor 18 is controlled based on the manual steering command value θ MD,cmd The virtual road load torque T used in the calculation of rl The steering reaction force based on the above will be reflected.

[0256] Next, the weight setting unit 49 calculates the vehicle lateral position P lat P L2(See Figure 25) and the heading angle θ vh It is determined whether or not the sixth condition that is smaller than 0 is satisfied (step S25).

[0257] If the sixth condition is not met (step S25: NO), the weight setting unit 49 returns to step S25.

[0258] If it is determined in step S25 that the sixth condition is satisfied (step S25: YES), the weight setting unit 49 sets the first weight W1 to 1 and the second weight W2 to 0 (step S26). At this time, it is preferable that the weight setting unit 49 gradually increases the first weight W1 from 0 to 1 and gradually decreases the second weight W2 from 1 to 0. The time taken to gradually increase the first weight W1 from 0 to 1 (the time taken to gradually decrease the second weight W2 from 1 to 0) may be, for example, about 0.1 seconds.

[0259] As a result, the control mode of the electric motor 18 becomes the first control mode. Note that while the first weight W1 is gradually increased (while the second weight W2 is gradually decreased), the assist torque command value W1·T after multiplication by the first weight asst and the integrated motor torque command value w2·T after multiplication by the second weight mint,cmd The electric motor 18 is controlled based on the sum of

[0260] In the first control mode, the manual steering command value θ MD,cmd The virtual road load torque T used in the calculation of rl The steering reaction force based on the steering angle is not reflected.

[0261] After the process of step S26 is performed, the weight setting unit 49 returns to step S22.

[0262] In step S22, when it is determined that the vehicle reference position is on the right side of the center of the lane (step S22: NO), the weight setting unit 49 calculates the vehicle lateral position P lat P R1 (See Figure 25) and the heading angle θ vhIt is determined whether or not the seventh condition that P is greater than 0 is satisfied (step S27). R1 is set to, for example, 110 cm.

[0263] If the seventh condition is not met (step S27: NO), the weight setting unit 49 returns to step S22.

[0264] If it is determined in step S27 that the seventh condition is satisfied (step S27: YES), the weight setting unit 49 sets the first weight W1 to 0 and the second weight W2 to 1 (step S28). At this time, it is preferable that the weight setting unit 49 gradually decreases the first weight W1 from 1 to 0 and gradually increases the second weight W2 from 0 to 1.

[0265] As a result, the control mode of the electric motor 18 is set to the second control mode. In the second control mode, the virtual road load torque T rl The steering reaction force based on the above will be reflected.

[0266] Next, the weight setting unit 49 calculates the vehicle lateral position P lat P R2 (See Figure 25) and the heading angle θ vh It is determined whether or not the eighth condition that is smaller than 0 is satisfied (step S29).

[0267] If the eighth condition is not satisfied (step S29: NO), the weight setting unit 49 returns to step S29.

[0268] If it is determined in step S29 that the eighth condition is satisfied (step S29: YES), the weight setting unit 49 sets the first weight W1 to 1 and the second weight W2 to 0 (step S30). At this time, it is preferable that the weight setting unit 49 gradually increases the first weight W1 from 0 to 1 and gradually decreases the second weight W2 from 1 to 0.

[0269] As a result, the control mode of the electric motor 18 is set to the first control mode. In the first control mode, the virtual road load torque T rl The steering reaction force based on the steering angle is not reflected.

[0270] After the process of step S30 is performed, the weight setting unit 49 returns to step S22.

[0271] Figure 25 shows the first vehicle lateral position P L1 ,P R1 and the second vehicle lateral position is set to P L2 ,P R2 When the setting is made, the virtual road load torque T rl 10 is a schematic diagram for explaining a steering reaction force generated based on the steering angle. FIG.

[0272] At time t0, the control mode is the first mode, and the vehicle reference position is in the center of the lane. Since the control mode is the first control mode, W1=1, W2=0, and the manual steering command value θ MD,cmd The virtual road load torque T used in the calculation of rl The steering reaction force based on is 0.

[0273] Immediately after time t0, the driver steers the vehicle to the right, causing the vehicle to start moving to the right. Then, at time t1, the vehicle lateral position P lat P R1 When the vehicle crosses the boundary of the right lane, θ vh >0, the seventh condition of step S27 in Fig. 24 is satisfied. As a result, W1 is gradually decreased and W2 is gradually increased, and at time t2, W1 = 0 and W2 = 1. That is, the control mode becomes the second control mode.

[0274] From time t0 to time t1, the manual steering command value θ MD,cmd The virtual road load torque T used in the calculation of rl is 0, but from time t1 to time t2, the virtual road load torque T rlSince a part of the steering reaction force based on the virtual road load torque T is reflected, the steering reaction force gradually increases. Then, from time t2, the control mode becomes the second control mode, and the virtual road load torque T rl The steering reaction force based on the steering angle becomes even larger.

[0275] Then, when the vehicle reference position reaches the right lane boundary (time t3), the steering reaction force reaches the maximum reaction force value. When the driver feels the steering reaction force and stops steering to the right, the vehicle moves toward the center of the lane. Then, when the vehicle reference position enters the lane center side beyond the right lane boundary (time t4), the virtual road load torque T rl Then, at time t5, the vehicle lateral position P lat P R2 When the vehicle crosses the center of the lane, θ vh <0, the eighth condition of step S29 in Fig. 24 is satisfied. As a result, W1 is gradually increased and W2 is gradually decreased, and at time t6, W1 = 1 and W2 = 0. That is, the control mode becomes the first control mode.

[0276] From time t5 to time t6, the virtual road load torque T rl Since a part of the steering reaction force based on the virtual road load torque T is reflected, the steering reaction force gradually decreases. rl The steering reaction force based on this is 0.

[0277] The third modified example has the following advantages over the previous embodiment described with reference to Fig. 12. When the vehicle is traveling in a direction that will cause it to deviate from its lane, it is preferable to promptly notify the driver of this. In the third modified example, the first vehicle lateral position is set closer to the center of the lane than the second vehicle lateral position in the previous embodiment, so that when the vehicle is traveling in a direction that will cause it to deviate from its lane, it is possible to transmit a steering reaction force to the driver earlier than in the previous embodiment.

[0278] [Fourth Modification of Weighting Setting Unit 49] In the fourth modified example, when the vehicle is on the left side of the lane center, the first vehicle lateral position for switching the first weight W1 from 1 to 0 (the second weight W1 from 0 to 1) is set to P L3 (P in Figure 12 L_start When the vehicle is on the left side of the lane center, the second vehicle lateral position for switching the first weight W1 from 0 to 1 (the second weight W1 from 1 to 0) is set to a value greater than 0 and P L3 (P in Figure 12 L_start In this case, the second vehicle lateral position when the vehicle is on the left side of the lane center is set within the range of P L4 It is assumed that it is set to.

[0279] When the vehicle is on the right side of the lane center, the first vehicle lateral position for switching the first weight W1 from 1 to 0 (the second weight W1 from 0 to 1) is P R3 (P in Figure 12 R_start When the vehicle is on the right side of the lane center, the second vehicle lateral position for switching the first weight W1 from 0 to 1 (the second weight W1 from 1 to 0) is set to a value greater than 0 and P R3 (P in Figure 12 R_start In this case, the second vehicle lateral position when the vehicle is on the right side of the lane center is set within the range of P R4 It is assumed that it is set to.

[0280] FIG. 26 is a flowchart showing the procedure of the weight setting process performed by the weight setting unit 49 according to the fourth modification in the driving assistance mode.

[0281] When the driving mode is changed to the driving assistance mode, the weight setting unit 49 sets the first weight W1 to 1 and the second weight W2 to 0 (step S31). As a result, the control mode of the electric motor 18 is changed to the assist torque command value T asst This results in a first control mode in which the electric motor 18 is driven and controlled only by the power supply.

[0282] When the driving mode is changed to the driving assistance mode, the host ECU 201 controls the automatic steering command value θ AD,cmd is set, and the automatic steering command value θ AD,cmd , mode signal S mode , left / right discrimination signal S LR and vehicle lateral position P lat is given to the motor control ECU 202.

[0283] Next, the weight setting unit 49 calculates the left / right discrimination signal S LR Based on this, it is determined whether the vehicle reference position is on the left side of the center of the lane (step S32).

[0284] If the vehicle reference position is on the left side of the lane center (step S32: YES), the weight setting unit 49 calculates the vehicle lateral position P lat P L3 (See Figure 27) and the heading angle θ vh It is determined whether or not the ninth condition that is greater than 0 is satisfied (step S33).

[0285] If the ninth condition is not met (step S33: NO), the weight setting unit 49 returns to step S32.

[0286] If it is determined in step S33 that the ninth condition is satisfied (step S33: YES), the weight setting unit 49 sets the first weight W1 to 0 and the second weight W2 to 1 (step S34). At this time, it is preferable that the weight setting unit 49 gradually decreases the first weight W1 from 1 to 0 and gradually increases the second weight W2 from 0 to 1. The time taken to gradually decrease the first weight W1 from 1 to 0 (the time taken to gradually increase the second weight W2 from 0 to 1) may be, for example, about 0.1 seconds.

[0287] As a result, the control mode of the electric motor 18 is set to the integrated motor torque command value T mint,cmd The second control mode is set in which the electric motor 18 is driven and controlled by the following equation. While the first weight W1 is gradually decreasing (while the second weight W2 is gradually increasing), the assist torque command value W1·T after multiplication by the first weight is asstand the integrated motor torque command value w2·T after multiplication by the second weight mint,cmd The electric motor 18 is controlled based on the sum of

[0288] In the second control mode, the manual steering command value θ MD,cmd and the automatic steering command value θ AD,cmd The integrated angle command value θ int,cmd Since the electric motor 18 is controlled based on the manual steering command value θ MD,cmd The virtual road load torque T used in the calculation of rl The steering reaction force based on the above will be reflected.

[0289] Next, the weight setting unit 49 calculates the vehicle lateral position P lat P L4 (See Figure 27) and the heading angle θ vh It is determined whether the tenth condition that P is smaller than 0 is satisfied (step S35). L4 is set to, for example, 30 cm.

[0290] If the tenth condition is not met (step S35: NO), the weight setting unit 49 returns to step S35.

[0291] If it is determined in step S35 that the tenth condition is satisfied (step S35: YES), the weight setting unit 49 sets the first weight W1 to 1 and the second weight W2 to 0 (step S36). At this time, it is preferable that the weight setting unit 49 gradually increases the first weight W1 from 0 to 1 and gradually decreases the second weight W2 from 1 to 0. The time taken to gradually increase the first weight W1 from 0 to 1 (the time taken to gradually decrease the second weight W2 from 1 to 0) may be, for example, about 0.1 seconds.

[0292] As a result, the control mode of the electric motor 18 becomes the first control mode. Note that while the first weight W1 is gradually increased (while the second weight W2 is gradually decreased), the assist torque command value W1·T after multiplication by the first weight asst and the integrated motor torque command value w2·T after multiplication by the second weight mint,cmdThe electric motor 18 is controlled based on the sum of

[0293] In the first control mode, the manual steering command value θ MD,cmd The virtual road load torque T used in the calculation of rl The steering reaction force based on the steering angle is not reflected.

[0294] After the process of step S36 is performed, the weight setting unit 49 returns to step S32.

[0295] In step S32, when it is determined that the vehicle reference position is on the right side of the center of the lane (step S32: NO), the weight setting unit 49 calculates the vehicle lateral position P lat P R3 (See Figure 27) and the heading angle θ vh It is determined whether or not the eleventh condition that is greater than 0 is satisfied (step S37).

[0296] If the eleventh condition is not met (step S37: NO), the weight setting unit 49 returns to step S32.

[0297] If it is determined in step S37 that the eleventh condition is satisfied (step S37: YES), the weight setting unit 49 sets the first weight W1 to 0 and the second weight W2 to 1 (step S28). At this time, it is preferable that the weight setting unit 49 gradually decreases the first weight W1 from 1 to 0 and gradually increases the second weight W2 from 0 to 1.

[0298] As a result, the control mode of the electric motor 18 is set to the second control mode. In the second control mode, the virtual road load torque T rl The steering reaction force based on the above will be reflected.

[0299] Next, the weight setting unit 49 calculates the vehicle lateral position P lat P R4 (See Figure 27) and the heading angle θ vh It is determined whether or not the twelfth condition that P is smaller than 0 is satisfied (step S39).R4 is set to, for example, 30 cm.

[0300] If the twelfth condition is not satisfied (step S39: NO), the weight setting unit 49 returns to step S39.

[0301] If it is determined in step S39 that the twelfth condition is satisfied (step S39: YES), the weight setting unit 49 sets the first weight W1 to 1 and the second weight W2 to 0 (step S40). At this time, it is preferable that the weight setting unit 49 gradually increases the first weight W1 from 0 to 1 and gradually decreases the second weight W2 from 1 to 0.

[0302] As a result, the control mode of the electric motor 18 is set to the first control mode. In the first control mode, the virtual road load torque T rl The steering reaction force based on the steering angle is not reflected.

[0303] After the process of step S40 is performed, the weight setting unit 49 returns to step S32.

[0304] Figure 27 shows the first vehicle lateral position P L3 ,P R3 and the second vehicle lateral position is set to P L4 ,P R4 When the setting is made, the virtual road load torque T rl 10 is a schematic diagram for explaining a steering reaction force generated based on the steering angle. FIG.

[0305] At time t0, the control mode is the first mode, and the vehicle reference position is in the center of the lane. Since the control mode is the first control mode, W1=1, W2=0, and the manual steering command value θ MD,cmd The virtual road load torque T used in the calculation of rl The steering reaction force based on is 0.

[0306] Immediately after time t0, the driver steers the vehicle to the right, causing the vehicle to start moving to the right. Then, at time t1, the vehicle lateral position P lat P R3When the vehicle crosses the boundary of the right lane, θ vh >0, the eleventh condition of step S37 in Fig. 26 is satisfied. As a result, W1 is gradually decreased and W2 is gradually increased, and at time t2, W1 = 0 and W2 = 1. That is, the control mode becomes the second control mode.

[0307] From time t0 to time t1, the manual steering command value θ MD,cmd The virtual road load torque T used in the calculation of rl is 0, but from time t1 to time t2, the virtual road load torque T rl Since a part of the steering reaction force based on the virtual road load torque T is reflected, the steering reaction force gradually increases. Then, from time t2, the control mode becomes the second control mode, and the virtual road load torque T rl The steering reaction force based on the steering angle becomes even larger.

[0308] Then, when the vehicle reference position reaches the right lane boundary (time t3), the steering reaction force reaches the maximum reaction force value. When the driver feels the steering reaction force and stops steering to the right, the vehicle moves toward the center of the lane. Then, when the vehicle reference position enters the lane center side beyond the right lane boundary (time t4), the virtual road load torque T rl Then, at time t5, the vehicle lateral position P lat P R4 When the vehicle crosses the center of the lane, θ vh <0, the twelfth condition of step S39 in Fig. 26 is satisfied. As a result, W1 is gradually increased and W2 is gradually decreased, and at time t6, W1 = 1 and W2 = 0. In other words, the control mode becomes the first control mode.

[0309] From time t5 to time t6, the virtual road load torque T rl Since a part of the steering reaction force based on the virtual road load torque T is reflected, the steering reaction force gradually decreases. rl The steering reaction force based on this is 0.

[0310] The fourth modified example has the following advantages over the previous embodiment described with reference to FIG. 12. In the fourth modified example, the second vehicle lateral position is set closer to the lane boundary than the first vehicle lateral position in the previous embodiment. Therefore, when the driver steers the vehicle in a direction to return it to the center of the lane after the control mode is switched from the first control mode to the second control mode, the steering reaction force to the driver can be nullified earlier than in the previous embodiment. This reduces the uncomfortable steering feeling caused by unnecessary steering reaction force when the driver operates the vehicle to return it to the center of the lane.

[0311] Although the embodiment and modifications of the present invention have been described above, the present invention can also be embodied in other forms.

[0312] In the above-described embodiment or modification, the virtual load spring stiffness coefficient k vl and the virtual load viscous damping coefficient c vl is the vehicle lateral position P lat or vehicle lateral position P lat and heading angle V vh The vehicle lateral position P lat The time differential value of the heading angle, etc. may be set to change depending on the time differential value of the heading angle, etc.

[0313] Also, the virtual load spring stiffness coefficient k vl and the virtual load viscous damping coefficient c vl A preset fixed value may be used for the .times. ...

[0314] In the above-described embodiment, the vehicle lateral position P lat is the distance from the boundary of the lane in which the vehicle is currently traveling (lane boundary) to the vehicle reference position, but the vehicle lateral position P lat may be the distance from the center of the lane in which the vehicle is currently traveling to the vehicle reference position.

[0315] In the above embodiment, the assist torque command value T asst is multiplied by the first weight W1, and the assist torque command value after multiplication by the first weight W1·T asstis given to the adder 47. However, instead of this, the manual steering command value θ MD,cmd The manual torque command value corresponding to the torque command value may be multiplied by a first weight W1, and the manual torque command value after multiplication with the first weight W1 may be provided to the adder 47.

[0316] In the above embodiment, the angle control unit 44 (see FIG. 5) includes the feedforward control unit 53, but the feedforward control unit 53 may be omitted. In this case, the feedback control torque T calculated by the feedback control unit 52 is fb is the basic target torque.

[0317] Furthermore, the driving assist control (LKA) according to this embodiment can also be used in conjunction with a lane centering assist (LCA) control that causes the vehicle to travel along the center of the lane.

[0318] Fig. 28 is a block diagram showing an example of a motor control ECU 40A when lane keep assist (LKA) control and lane centering assist (LCA) control are used together. In Fig. 28, parts corresponding to those in Fig. 2 are denoted by the same reference numerals as in Fig. 2.

[0319] In the motor control ECU 202A of FIG. 28, compared to the motor control ECU 202 of FIG. 2, the functional configuration of the microcomputer 40A is different from the functional configuration of the microcomputer 40 of FIG.

[0320] Specifically, the microcomputer 40A in Fig. 28 does not include the weight setting unit 49 in Fig. 2. That is, the microcomputer 40A includes an assist torque command value setting unit 41, a manual steering command value generating unit 42, an integrated angle command value calculating unit 43, an angle control unit 44, a first weight multiplying unit 45, a second weight multiplying unit 46, an adding unit 47, and a torque control unit 48.

[0321] The first weight W1 used in the first weight multiplication unit 45 and the first weight W2 used in the second weight multiplication unit 46 are set to predetermined values ​​in advance. For example, when lane keep assist (LKA) control and lane centering assist (LCA) control are used in combination, the first weight W1 is set to 0 and the second weight W2 is set to 1. When fully manual steering is performed, the first weight W1 is set to 1 and the second weight W2 is set to 0. Here, it is assumed that the first weight W1 is set to 0 and the second weight W2 is set to 1.

[0322] The operations of the assist torque command value setting unit 41, angle control unit 44 and torque control unit 48 are similar to those of the assist torque command value setting unit 41, angle control unit 44 and torque control unit 48 in FIG. 2, and therefore will not be described again.

[0323] The operation of the manual steering command value generating unit 42 will be described.

[0324] Road load torque (virtual road load torque) T rl is the virtual load spring stiffness coefficient k vl , virtual load viscous damping coefficient c vl and manual steering command value θ MD,cmd is expressed by the above formula (1).

[0325] Figure 29 shows the lateral position of the vehicle P lat Virtual load spring stiffness coefficient k vl 29 is a graph showing an example of setting the following: The subscript L of the symbol in Fig. 29 indicates that the symbol is applied when the vehicle reference position is to the left of the center of the lane, and the subscript R indicates that the symbol is applied when the vehicle reference position is to the right of the center of the lane.

[0326] Vehicle lateral position P lat is the left lane boundary relative to the given P LA or above or to the right lane boundary as specified P RA If it is greater than or equal to the virtual load spring stiffness coefficient k vl is set to a predetermined value k1.

[0327] Vehicle lateral position P latHowever, P LA smaller than the given P LB Above and P LA If it is less than the virtual load spring stiffness coefficient k vl is the vehicle lateral position P lat P LA As the vehicle reference position gets closer to the left lane boundary, the value of k1 to k max The characteristic is set according to the increasing characteristics.

[0328] Vehicle lateral position P lat However, P LA smaller than the given P RB Above and P RA If it is less than the virtual load spring stiffness coefficient k vl is the vehicle lateral position P lat P RA As the vehicle reference position gets closer to the right lane boundary, the value of k1 to k max The characteristic is set according to the increasing characteristics.

[0329] Vehicle lateral position P lat is P relative to the left lane boundary LB If it is less than the virtual load spring stiffness coefficient k vl is k max Vehicle lateral position P lat is P relative to the right lane boundary RB If it is less than the virtual load spring stiffness coefficient k vl is k max is set to

[0330] Vehicle lateral position P lat Virtual load viscous damping coefficient c vl However, the characteristics are different depending on the vehicle lateral position P lat Virtual load spring stiffness coefficient k vl The vehicle lateral position P lat Virtual load viscous damping coefficient c vl A detailed description of the above will be omitted.

[0331] The manual steering command value generating unit 42 calculates the manual steering command value θ based on the above equation (2). MD,cmd Specifically, the manual steering command value generating unit 42 calculates T tb The torsion bar torque T detected by the torque sensor 12 is tb Substituting T in equation (2), asst The assist torque command value T set by the assist torque command value setting unit 41 is asst By substituting and solving the differential equation (2), the manual steering command value θ MD,cmd Calculate the following.

[0332] Referring to FIG. 28, the host ECU (not shown) detects the vehicle lateral position P lat and the automatic steering command value θ AD,cmd is generated and given to the motor control ECU 202A. In this example, the automatic steering command value θ AD,cmd is the target value of the steering angle for driving the vehicle along the center line of the lane.

[0333] Furthermore, the upper ECU detects the vehicle lateral position P lat is P relative to the left lane boundary LB If P is RB If the target vibration waveform is less than the predetermined value, the vibration angle command value θ cv,cmd is generated and given to the motor control ECU 202A. cv,cmd is an instantaneous value of the target vibration waveform expressed in terms of the rotation angle of the output shaft (steering shaft) 9. The target vibration waveform has a specified target amplitude and a predetermined target frequency.

[0334] An example of a target vibration waveform is shown in Fig. 30. In the example of Fig. 30, the target amplitude is set to 0.5 [deg], and the target frequency is set to 30 [Hz].

[0335] The integrated angle command value calculation unit 43 receives the manual steering command value θ calculated by the manual steering command value generation unit 42. MD,cmdThe integrated angle command value calculation unit 43 further receives an automatic steering command value θ AD,cmd and vibration angle command value θ cv,cmd is given.

[0336] The integrated angle command value calculation unit 43 receives the vibration angle command value θ cv,cmd is not given, the integrated angle command value calculation unit 43 calculates the automatic steering command value θ AD,cmd , manual steering command value θ MD,cmd The integrated angle command value θ int,cmd The vibration angle command value θ cv,cmd is given, the integrated angle command value calculation unit 43 calculates the automatic steering command value θ AD,cmd , vibration angle command value θ cv,cmd and manual steering command value θ MD,cmd The integrated angle command value θ int,cmd Calculate the following.

[0337] The angle control unit 44 calculates the integrated angle command value θ int,cmd Based on this, the integrated angle command value θ int,cmd The integrated motor torque command value T mint,cmd In this example, the first weight W1 is set to 0 and the second weight W2 is set to 1, so the integrated motor torque command value T mint,cmd is the motor torque command value T m,cmd is given to the torque control section 48 as

[0338] Figure 31 shows the virtual load spring stiffness coefficient k vl The characteristics are shown in Figure 29, and the virtual load viscous damping coefficient c vl The vehicle lateral position P lat and steering reaction force T reac Absolute value of |T reac 10 is a graph showing an example of the relationship between |

[0339] Vehicle lateral position P lat is P relative to the left lane boundary LA In the above cases, the steering reaction force T reac Absolute value of |T reac|(Virtual road load torque T rl Absolute value of |T rl |) is P from the center of the lane LA The closer to , the greater the difference between 0 and T reac1 In the example in Figure 31, |T reac | increases linearly. In this range, lane centering assist (LCA) control is performed.

[0340] Vehicle lateral position P lat However, P LB Above and P LA If it is less than the steering reaction force T reac Absolute value of |T reac |(Virtual road load torque T rl Absolute value of |T rl |) is the vehicle lateral position P lat P LA The smaller the value is (the closer the vehicle reference position is to the left lane boundary), the greater the T reac1 From T reac2 In the example in Figure 31, |T reac | increases nonlinearly. In this range, lane keep assist (LKA) control is performed.

[0341] Vehicle lateral position P lat P LB When the steering reaction force T reac Absolute value of |T reac | is T reac2 Vibration angle command value θ cv,cmd Vibration torque T according to cv This results in the sum of both lateral positions P lat P LB When the vehicle speed drops below this threshold, a warning vibration can be transmitted to the driver.

[0342] Vehicle lateral position P lat is P relative to the right lane boundary RA In the above cases, the steering reaction force T reac Absolute value of |T reac |(Virtual road load torque T rl Absolute value of |T rl |) is P from the center of the lane RAThe closer to , the greater the difference between 0 and T reac1 In the example in Figure 31, |T reac | increases linearly. In this range, lane centering assist (LCA) control is performed.

[0343] Vehicle lateral position P lat However, P RB Above and P RA If it is less than the steering reaction force T reac Absolute value of |T reac |(Virtual road load torque T rl Absolute value of |T rl |) is the vehicle lateral position P lat P RA The smaller the value is (the closer the vehicle reference position is to the left lane boundary), the greater the T reac1 From T reac2 In the example in Figure 31, |T reac | increases nonlinearly. In this range, lane keep assist (LKA) control is performed.

[0344] Vehicle lateral position P lat P RB When the steering reaction force T reac Absolute value of |T reac | is T reac2 Vibration angle command value θ cv,cmd Vibration torque T according to cv This results in the sum of both lateral positions P lat P RB When the vehicle speed drops below this threshold, a warning vibration can be transmitted to the driver.

[0345] In the above-described embodiment and modified examples, the present invention is applied to a column-type EPS, but the present invention can also be applied to EPSs other than column types. The present invention can also be applied to steer-by-wire systems.

[0346] Although the embodiments of the present invention have been described in detail, these are merely examples used to clarify the technical contents of the present invention, and the present invention should not be construed as being limited to these examples, and the scope of the present invention is limited only by the appended claims.

[0347] This application corresponds to an international patent application (PCT / JP2021 / 041059) filed with the Japan Patent Office as a receiving office on November 8, 2021, the entire disclosure of which is incorporated herein by reference. [Explanation of symbols]

[0348] 1... electric power steering device, 3... steered wheels, 4... steering mechanism, 18... electric motor, 41... assist torque command value setting unit, 42... manual steering command value generation unit, 43... integrated angle command value calculation unit, 44... angle control unit, 45... first weight multiplication unit, 46... second weight multiplication unit, 47... addition unit, 48... torque control unit, 49... weight setting unit, 50... hands-on / off determination unit

Claims

1. A motor control device for driving and controlling an electric motor for steering angle control, an assist torque command value generating unit that generates an assist torque command value using the steering torque; a manual steering command value generating unit that generates a manual steering command value using the steering torque and the assist torque command value; an integrated angle command value calculation unit that calculates an integrated angle command value by adding the manual steering command value to an automatic steering command value for driving assistance; a switching unit that switches, in a driving assistance mode, between a first control mode in which the electric motor is controlled based on the assist torque command value or the manual steering command value and a second control mode in which the electric motor is controlled based on the integrated angle command value, in accordance with a lateral position of the vehicle with respect to a lane; The manual steering command value is calculated in consideration of a virtual road surface load torque, A motor control device wherein the virtual road load torque is set according to a lateral position of the vehicle relative to the lane.

2. a first lateral position, which is the lateral position at which the control mode is switched from the first control mode to the second control mode, and a second lateral position, which is the lateral position at which the control mode is switched from the second control mode to the first control mode, are set in advance; 2. The motor control device according to claim 1, wherein the steering reaction force applied to the driver when the vehicle moves from the lane boundary to the second lateral position has a first characteristic in which the rate of decrease of the steering reaction force is large, and a second characteristic that is continuous with the first characteristic and in which the rate of decrease of the steering reaction force is smaller than the first characteristic.

3. 2. The motor control device according to claim 1, wherein a first lateral position at which the first control mode is switched to the second control mode and a second lateral position at which the second control mode is switched to the first control mode are set to different positions.

4. The motor control device according to claim 3 , wherein the second lateral position is set closer to the center of the lane than the first lateral position.

5. The motor control device according to claim 3 , wherein the first lateral position is set closer to the center of the lane than the second lateral position.

6. A motor control device for driving and controlling an electric motor for steering angle control, comprising: an assist torque command value generating unit that generates an assist torque command value using the steering torque; a manual steering command value generating unit that generates a manual steering command value using the steering torque and the assist torque command value; an integrated angle command value calculation unit that calculates an integrated angle command value by adding the manual steering command value to an automatic steering command value for driving assistance; a switching unit that switches, in a driving assistance mode, between a first control mode in which the electric motor is controlled based on the assist torque command value or the manual steering command value and a second control mode in which the electric motor is controlled based on the integrated angle command value, in accordance with a lateral position of the vehicle with respect to a lane; a first lateral position, which is the lateral position at which the control mode is switched from the first control mode to the second control mode, and a second lateral position, which is the lateral position at which the control mode is switched from the second control mode to the first control mode, are set in advance; A motor control device wherein the steering reaction force applied to the driver when the vehicle moves from the lane boundary of the lane to the second lateral position has a first characteristic in which the rate of decrease of the steering reaction force is large, and a second characteristic that is continuous with the first characteristic and in which the rate of decrease of the steering reaction force is smaller than the first characteristic.

7. A motor control device as described in Claim 6, wherein the manual steering command value is configured to be calculated taking into account a virtual road surface load torque.

8. A motor control device for driving and controlling an electric motor for steering angle control, comprising: an assist torque command value generating unit that generates an assist torque command value using the steering torque; a manual steering command value generating unit that generates a manual steering command value using the steering torque and the assist torque command value; an integrated angle command value calculation unit that calculates an integrated angle command value by adding the manual steering command value to an automatic steering command value for driving assistance; a switching unit that switches, in a driving assistance mode, between a first control mode in which the electric motor is controlled based on the assist torque command value or the manual steering command value and a second control mode in which the electric motor is controlled based on the integrated angle command value, in accordance with a lateral position of the vehicle with respect to a lane; The manual steering command value is calculated in consideration of a virtual road surface load torque, The motor control device, wherein the virtual road load torque is set in accordance with an angle formed by the traveling direction of the vehicle with respect to the lane.

9. A motor control device for driving and controlling an electric motor for steering angle control, comprising: an assist torque command value generating unit that generates an assist torque command value using the steering torque; a manual steering command value generating unit that generates a manual steering command value using the steering torque and the assist torque command value; an integrated angle command value calculation unit that calculates an integrated angle command value by adding the manual steering command value to an automatic steering command value for driving assistance; a switching unit that switches, in a driving assistance mode, between a first control mode in which the electric motor is controlled based on the assist torque command value or the manual steering command value and a second control mode in which the electric motor is controlled based on the integrated angle command value, in accordance with a lateral position of the vehicle with respect to a lane; The manual steering command value is calculated in consideration of a virtual road surface load torque, A motor control device wherein the virtual road load torque is set based on information about the outside of the lane in which the vehicle is traveling.

Images