Motor control device

Abstract

In principle, this motor control device includes: a manual steering angle command value calculation unit that calculates a manual steering angle command value by solving a differential equation in which steering torque is used, the differential equation being an equation of motion of a reference model of a steering device; an integrated angle command value calculation unit that calculates an integrated angle command value on the basis of an automatic steering angle command value and the manual steering angle command value; and a control unit capable of controlling an electric motor on the basis of the integrated angle command value. When a predetermined condition is satisfied, the manual steering angle command value calculation unit resets the initial value of a solution of the differential equation using a value obtained by subtracting the automatic steering angle command value from an actual steering angle.

Description

Motor control device

[0001] This disclosure relates to a motor control device.

[0002] Patent Document 1 discloses a motor control device comprising: an assist torque command value setting unit that sets an assist torque command value using torsion bar torque; a manual steering angle command value generation unit that generates a manual steering angle command value using torsion bar torque and assist torque command value; an integrated angle command value calculation unit that calculates an integrated angle command value by adding the manual steering angle command value to the automatic steering angle command value; and a switching unit that switches between a first control that controls the electric motor based only on the assist torque command value and a second control that controls the electric motor based on the integrated angle command value, based on a switching signal.

[0003] When the driving mode is manual driving mode, the electric motor is controlled by the first control. On the other hand, when driving assistance is in operation, such as lane centering assist (LCA) control, the electric motor is controlled by the second control.

[0004] International Publication No. 2023 / 286169, Japanese Patent Publication No. 2020-132008

[0005] The purpose of this disclosure is to provide a motor control device with a novel configuration.

[0006] One embodiment of the present disclosure provides a motor control device for driving and controlling an electric motor capable of controlling the steering angle of a steering device, and includes, in principle, a manual steering angle command value calculation unit that calculates a manual steering angle command value by solving a differential equation which is the equation of motion of a reference model of the steering device, using steering torque; an integrated angle command value calculation unit that calculates an integrated angle command value based on an automatic steering angle command value and the manual steering angle command value; and a control unit capable of controlling the electric motor based on the integrated angle command value, wherein the manual steering angle command value calculation unit, when a predetermined condition is met, resets the initial value of the solution to the differential equation using a value obtained by subtracting the automatic steering angle command value from the actual steering angle.

[0007] The above-mentioned or further other purposes, features, and effects of this disclosure will be made apparent by the following description of embodiments with reference to the accompanying drawings.

[0008] Figure 1 is a schematic diagram showing the general configuration of an electric power steering system to which the motor control device according to the first embodiment of this disclosure is applied. Figure 2 is a block diagram for explaining the electrical configuration of the motor control ECU. Figure 3 is a schematic diagram showing an example of a reference EPS model used in the manual steering angle command value calculation unit. Figures 4A, 4B, and 4C are graphs for explaining the effects of the first embodiment. Figure 5 is a schematic diagram showing the general configuration of an electric power steering system to which the motor control device according to the second embodiment of this disclosure is applied. Figure 6 is a block diagram for explaining the electrical configuration of the reaction force ECU and the steering ECU. Figure 7 is a schematic diagram showing the general configuration of an electric power steering system to which the motor control device according to the third embodiment of this disclosure is applied. Figure 8 is a block diagram for explaining the electrical configuration of the motor control ECU in Figure 7. Figure 9 is a block diagram for explaining the electrical configuration of the manual steering angle command value calculation unit in Figure 7. Figure 10 is a schematic diagram showing the general configuration of an electric power steering system to which the motor control device according to the fourth embodiment of this disclosure is applied. Figure 11 is a block diagram for explaining the electrical configuration of the motor control ECU in Figure 10. Figure 12 is a block diagram illustrating the electrical configuration of the assist control unit shown in Figure 10. Figure 13 shows the torsion bar torque command value T with respect to lateral G. ｔｂ，ｃｍｄ This is a graph showing an example of the settings. Figure 14 is a block diagram illustrating the electrical configuration of the coordinated steering control unit in Figure 10. Figure 15 is a block diagram illustrating the electrical configuration of the manual steering angle command value calculation unit in Figure 14.

[0009] [Description of Embodiments of the Disclosure] One embodiment of the Disclosure provides a motor control device for driving and controlling an electric motor capable of controlling the steering angle of a steering device, and includes, in principle, a manual steering angle command value calculation unit that calculates a manual steering angle command value by solving a differential equation which is the equation of motion of a reference model of the steering device, using steering torque; an integrated angle command value calculation unit that calculates an integrated angle command value based on an automatic steering angle command value and the manual steering angle command value; and a control unit capable of controlling the electric motor based on the integrated angle command value, wherein the manual steering angle command value calculation unit, when a predetermined condition is met, resets the initial value of the solution to the differential equation using a value obtained by subtracting the automatic steering angle command value from the actual steering angle.

[0010] In one embodiment of the present disclosure, the condition is that it is determined that the automatic steering angle command value has changed abruptly.

[0011] In one embodiment of the present disclosure, the manual steering angle command value calculation unit determines that the condition is met when the absolute value of the amount of change of the automatic steering angle command value per predetermined time is equal to or greater than a predetermined value.

[0012] In one embodiment of the present disclosure, the upper-level ECU provides the manual steering angle command value calculation unit with the automatic steering angle command value and a determination signal indicating whether or not the automatic steering angle command value has changed abruptly. The manual steering angle command value calculation unit determines whether or not the condition has been met based on the determination signal from the upper-level ECU.

[0013] In one embodiment of the present disclosure, a final automatic steering angle command value calculation unit is included that calculates a final automatic steering angle command value based on the automatic steering angle command value, and the final automatic steering angle command value calculation unit is configured to perform a gradual change process so that the final automatic steering angle command value gradually approaches the automatic steering angle command value after the lane change when it is determined that a lane change has been performed, and the condition is that the gradual change process is being executed.

[0014] In one embodiment of the present disclosure, the present invention includes an assist control unit that calculates an assist torque command value used in manual steering mode, a cooperative steering control unit that calculates a cooperative torque command value used in cooperative steering mode, which corresponds to the integrated angle command value, and a combining unit that calculates a final torque command value by adding a value obtained by multiplying the assist torque command value by a first weight corresponding to the steering mode and a value obtained by multiplying the cooperative torque command value by a second weight corresponding to the steering mode, wherein the control unit is configured to control the electric motor based on the final torque command value, and when switching modes from manual steering mode to cooperative steering mode, the first weight and the second weight are controlled to gradually decrease the assist torque command value and gradually increase the cooperative torque command value, and the condition is that the gradual change process is being executed.

[0015] [Detailed Description of Embodiments of the Disclosure] Embodiments of the Disclosure will be described in detail below with reference to the accompanying drawings. Figure 1 is a schematic diagram showing the general configuration of an electric power steering system to which a motor control device according to the first embodiment of the Disclosure is applied. 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 the steering wheels 3 in conjunction with the rotation of the steering wheel 2, and a steering assist mechanism 5 for assisting the driver's steering. The steering wheel 2 and the steering mechanism 4 are mechanically connected via a steering shaft 6 and an intermediate shaft 7.

[0016] 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 rotatable relative to each other.

[0017] A torque sensor 12 is positioned near the torsion bar 10. The torque sensor 12 measures the torsion bar torque (steering torque) T applied to the steering wheel 2 based on the relative rotational displacement of the input shaft 8 and the output shaft 9. ｔｂThe torsion bar torque T detected by the torque sensor 12 is detected. In this embodiment, the torsion bar torque T is detected by the torque sensor 12. ｔｂ For example, the torque for steering to the left is detected as a positive value, and the torque for steering to the right is detected as a negative value, and the larger the absolute value, the greater the torsion bar torque T. ｔｂ Assume that the size of will increase.

[0018] The steering mechanism 4 consists of a rack and pinion mechanism including a pinion shaft 13 and a rack shaft 14 as the steering axis. Steering 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.

[0019] The rack shaft 14 extends linearly along the left-right direction of the vehicle. A rack 17 that meshes with the pinion 16 is formed in the axial middle portion of the rack shaft 14. The rotation of the pinion shaft 13 is converted into axial movement of the rack shaft 14 by the pinion 16 and the rack 17. By moving the rack shaft 14 in the axial direction, the steering wheels 3 can be steered.

[0020] 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. This causes the steering wheel 3 to turn.

[0021] The steering assist mechanism 5 includes an electric motor 18 for generating steering assist force (assist torque) and a reduction gear 19 for amplifying the output torque of the electric motor 18 and transmitting it to the steering mechanism 4. The electric motor 18 is an example of an "electric motor capable of controlling the steering angle of the steering device" in this disclosure. The reduction gear 19 consists of a worm gear mechanism including a worm gear 20 and a worm wheel 21 that meshes with the worm gear 20. The reduction gear 19 is housed in a gear housing 22 which serves as a transmission mechanism housing.

[0022] In the following description, the reduction ratio (gear ratio) of the speed reducer 19 is represented by N. The reduction ratio N is the rotation angle of the worm wheel 21, that is, the worm wheel angle θ ｗｗ with respect to the rotation angle of the worm gear 20, that is, the worm gear angle θ ｗｇ ratio (θ ｗｇ / θ ｗｗ ) is defined as.

[0023] The worm gear 20 is rotationally driven by the electric motor 18. Further, the worm wheel 21 is coupled to the output shaft 9 so as to be rotatable integrally therewith.

[0024] When the worm gear 20 is rotationally driven by the electric motor 18, the worm wheel 21 is rotationally driven, motor torque is applied to the steering shaft 6, and the steering shaft 6 (output shaft 9) rotates. Then, the rotation of the steering shaft 6 is transmitted to the pinion shaft 13 via the intermediate shaft 7. The rotation of the pinion shaft 13 is converted into axial movement of the rack shaft 14. Thereby, the steered wheels 3 are steered. That is, by rotationally driving the worm gear 20 with the electric motor 18, steering assist by the electric motor 18 and steering of the steered wheels 3 can be performed. 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.

[0025] As torques applied to the output shaft 9 (an example of a drive target of the electric motor 18), there are motor torque from the electric motor 18 and disturbance torque T other than the motor torque ｌｃ There is disturbance torque T other than motor torque ｌｃ includes torsion bar torque T ｔｂ , road surface reaction torque (road surface load torque) T ｒｌ , friction torque T ｆ and the like.

[0026] The torsion bar torque T ｔｂ is torque applied to the output shaft 9 from the steering wheel 2 side by a force applied to the steering wheel 2 by a driver, a force generated by steering wheel inertia, or the like.

[0027] Road surface reaction torque T ｒｌ This is the torque applied to the output shaft 9 via the rack shaft 14 from the steering wheel 3 side, due to the self-aligning torque generated in the tires, the force generated by the suspension and tire-wheel alignment, the frictional force of the rack and pinion mechanism, etc.

[0028] The vehicle is equipped with a CCD (Charge Coupled Device) camera 25 for photographing the road ahead in the direction of travel, a GPS (Global Positioning System) 26 for detecting the vehicle's position, a radar 27 for detecting road shape and obstacles, and a map information memory 28 for storing map information. The vehicle is also equipped with two mode switches 31 and 32 for manually switching the steering mode. As will be described later, there are two steering modes: a manual steering mode in which steering is performed by manual driving, and a cooperative steering mode in which steering is possible based on both manual and automated driving.

[0029] The CCD camera 25, GPS 26, radar 27, and map information memory 28 are connected to a higher-level ECU (Electronic Control Unit) 201 for performing driver assistance control and autonomous driving control. Based on the information obtained from the CCD camera 25, GPS 26, and radar 27, as well as map information, the higher-level ECU 201 performs surrounding environment recognition, vehicle position estimation, route planning, etc., and determines control target values ​​for steering and drive actuators.

[0030] In this embodiment, the higher-level ECU 201 sets the automatic steering angle command value θ for automatic steering. ＡＤ Set the following. In this embodiment, automatic steering control is, for example, control to make the vehicle travel along a target driving line (target trajectory). Automatic steering angle command value θ ＡＤ This is the target value for the steering angle required to automatically drive the vehicle along the target driving line.

[0031] In this embodiment, the automatic steering angle command value θ ＡＤThis is expressed as the amount of rotation (rotation angle) from the neutral position of the output shaft 9, where a rotation amount to the left from the neutral position is represented as a positive value, and a rotation amount to the right from the neutral position is represented as a negative value. Automatic steering angle command value θ ＡＤ This is set, for example, based on vehicle speed, lateral deviation from the target driving line, and yaw deviation of the vehicle from the target driving line. Such an automatic steering angle command value θ ＡＤ The process for setting this is well-known, so a detailed explanation will be omitted here.

[0032] Automatic steering control (driving assistance control) may include, for example, lane centering assist (LCA) control, which assists steering to keep the vehicle in the center of the driving lane, or lane keeping assist (LKA) control, which assists steering to keep the vehicle within the driving lane.

[0033] Furthermore, the higher-level ECU 201, based on the operation of the first mode switch 31 and the second mode switch 32, provides a steering mode signal S indicating whether the steering mode (driving mode) is manual steering mode (manual driving mode) or cooperative steering mode (driving assistance mode). ｍｏｄｅ Outputs.

[0034] Specifically, when the first mode switch 31 is turned on by the driver, the higher-level ECU 201 receives a steering mode signal S indicating that the steering mode is manual steering mode. ｍｏｄｅ It outputs the following. On the other hand, when the second mode switch 32 is turned on by the driver, the higher-level ECU 201 outputs a steering mode signal S indicating that the steering mode is cooperative steering mode. ｍｏｄｅ Outputs.

[0035] Auto steering angle command value θ ＡＤ and steering mode signal S ｍｏｄｅ This is provided to the motor control ECU 202 via the in-vehicle network. Torsion bar torque T detected by torque sensor 12 ｔｂ The output signal from 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 higher-level ECU 201.

[0036] Figure 2 is a block diagram illustrating the electrical configuration of the motor control ECU 202. The motor control ECU 202 consists of a microcomputer 50, a drive circuit (inverter circuit) 41 controlled by the microcomputer 50 that supplies power to the electric motor 18, and the current (hereinafter referred to as "motor current I") that flows through the electric motor 18. ｍ It includes a current detection circuit 42 for detecting the following:

[0037] The microcomputer 50 is equipped with a CPU and memory (ROM, RAM, non-volatile memory, etc.) and functions as multiple function processing units by executing a predetermined program. The multiple function processing units include a reduction ratio multiplication unit 51, a rotation angle calculation unit 52, a reduction ratio division unit 53, an assist torque command value setting unit 54, a manual steering angle command value calculation unit 55, an integrated angle command value calculation unit 56, an angle control unit 57, a first switch 58, a second switch 59, an addition unit 60, and a torque control unit (current control unit) 61.

[0038] The microcomputer 50 generates a motor torque command value T at predetermined calculation cycles. ｍ，ｃｍｄ The motor torque command value T is calculated and obtained. ｍ，ｃｍｄ The drive circuit 41 is driven based on this.

[0039] The reduction ratio multiplication unit 51 multiplies the motor torque command value T output from the addition unit 60. ｍ，ｃｍｄ By multiplying this by the reduction ratio N, the motor torque command value T is obtained. ｍ，ｃｍｄ Output shaft torque command value T ｐ，ｃｍｄ Convert to.

[0040] The rotation angle calculation unit 52 calculates the rotor rotation angle θ of the electric motor 18 based on the output signal of the rotation angle sensor 23. ｍ The reduction ratio division unit 53 calculates the rotor rotation angle θ. ｍ By dividing by the reduction ratio N, the rotor rotation angle θ is obtained. ｍ The rotation angle (actual steering angle) of the output shaft 9 is θ ｐ Convert to the actual steering angle θ. In this embodiment, the actual steering angle θ ｐThis is expressed as the amount of rotation (rotation angle) from the neutral position of the output shaft 9, with a positive value representing rotation in the left steering direction from the neutral position, and a negative value representing rotation in the right steering direction from the neutral position.

[0041] The assist torque command value setting unit 54 sets the assist torque command value T, which is the target value of the assist torque required for manual steering. ａｓ The torsion bar torque T is set. The assist torque command value setting unit 54 sets the torsion bar torque T ｔｂ Based on this, the assist torque command value T corresponds to the output value of the electric motor 18. ａｓ Set it.

[0042] As the assist torque command value setting unit 54, for example, the assist torque command value setting unit (51) shown in Figure 2 of International Publication No. 2023 / 286169 (Patent Document 1) can be used. In that case, the torsion bar torque T ｔｂ Assist torque command value T ａｓ As an example of the settings, the example shown in Figure 3 of International Publication No. 2023 / 286169 can be used. The assist torque command value setting unit 54 is set to the torsion bar torque T ｔｂ And the assist torque command value T takes into account the vehicle speed. ａｓ The setting may also be configured. In addition, the assist torque command value setting unit 54 sets the torsion bar torque T ｔｂ By multiplying by a preset constant, the assist torque command value T is obtained. ａｓ You may perform the calculation.

[0043] The manual steering angle command value calculation unit 55, in principle, calculates the steering angle (more precisely, the rotation angle θ of the output shaft 9) corresponding to the steering wheel operation when the driver operates the steering wheel 2 in cooperative steering mode. ｐ ) to the manual steering angle command value θ ＭＤ It is provided for setting as such. However, in the first embodiment, the manual steering angle command value calculation unit 55 calculates the automatic steering angle command value θ ＡＤ When the steering angle changes suddenly, the steering angle θ ｐ Manual steering angle command value θ to suppress sudden changes ＭＤIt has the function of calculating the manual steering angle command value. Details of the operation of the manual steering angle command value calculation unit 55 will be described later.

[0044] The integrated angle command value calculation unit 56 calculates the automatic steering angle command value θ. ＡＤ The manual steering angle command value θ ＭＤ Adding this, the integrated angle command value θ ｃｍｄ Perform the calculation.

[0045] The angle control unit 57 controls the actual steering angle θ calculated by the reduction ratio division unit 53. ｐ The integrated angle command value θ ｃｍｄ (=θ) ＡＤ +θ ＭＤ ) performs control to make it follow the integrated angle command value θ. Specifically, the angle control unit 57 controls the integrated angle command value θ ｃｍｄ The actual steering angle θ is calculated by the reduction ratio division unit 53. ｐ The output shaft torque command value T is calculated by the reduction ratio multiplication unit 51. ｐ，ｃｍｄ Based on this, the integrated angle command value θ ｃｍｄ The corresponding integrated motor torque command value T ｃｍｄ The angle control unit 57 can be, for example, a configuration in which the reduction ratio multiplication unit (68), rotation angle calculation unit (69), and reduction ratio division unit (70) are removed from the angle control unit (54) shown in Figure 5 of International Publication No. 2023 / 286169 (Patent Document 1). The reason for removing the reduction ratio multiplication unit (68), rotation angle calculation unit (69), and reduction ratio division unit (70) is that the reduction ratio multiplication unit (68), rotation angle calculation unit (69), and reduction ratio division unit (70) correspond to the reduction ratio multiplication unit 51, rotation angle calculation unit 52, and reduction ratio division unit 53 in Figure 2 of this application, respectively. Note that θ in Figure 5 of International Publication No. 2023 / 286169 ｓｉｎｔ θ, N・T ｍ and T ｍｉｎｔ These are the θ values ​​in Figure 2 of the present application, respectively. ｃｍｄ , θ ｐ , T ｐ，ｃｍｄ and T ｃｍｄ It corresponds to this.

[0046] The first switch 58 and the second switch 59 receive a steering mode signal S from the higher-level ECU 201. ｍｏｄｅIt is turned on or off accordingly. Specifically, the steering mode signal S indicates that the steering mode is manual steering mode. ｍｏｄｅ If this is input, the first switch 58 is turned on and the second switch 59 is turned off. Meanwhile, the steering mode signal S indicates that the steering mode is the cooperative steering mode. ｍｏｄｅ If this is entered, the first switch 58 is turned off and the second switch 59 is turned on.

[0047] When the first switch 58 is ON and the second switch 59 is OFF, the adder 60 sets the assist torque command value T ａｓ The motor torque command value T ｍ，ｃｍｄ (=T ａｓ ) is output as. On the other hand, when the second switch 59 is ON and the first switch 58 is OFF, the adder 60 outputs the integrated motor torque command value T from the angle control unit 57. ｃｍｄ motor torque command value T ｍ，ｃｍｄ (=T ｃｍｄ The output of the summing unit 60 is the motor torque command value T. ｍ，ｃｍｄ This is supplied to the torque control unit 61.

[0048] The torque control unit 61 controls the motor torque of the electric motor 18 when it reaches the motor torque command value T. ｍ，ｃｍｄ The drive circuit 41 is driven to approach this value. As the torque control unit 61, for example, the torque control unit (55) shown in Figures 2 and 8 of International Publication No. 2023 / 286169 (Patent Document 1) can be used. In that case, the torque control unit 61 receives the motor torque command value T ｍ，ｃｍｄ The current command value is calculated by dividing by the torque coefficient of the electric motor 18. Then, the torque control unit 61 calculates the motor current I detected by the current detection circuit 42. ｍ Feedback control is performed to bring the current command value closer to the target value.

[0049] The operation of the manual steering angle command value calculation unit 55 will be described in detail below. The manual steering angle command value calculation unit 55 calculates the automatic steering angle command value θ at each calculation cycle. ＡＤdetermines whether has suddenly changed, and calculates a manual steering angle command value θ ＭＤ by a calculation method corresponding to the determination result.

[0050] Whether an automatic steering angle command value θ ＡＤ has suddenly changed or not is determined based on whether the absolute value of a change amount of the automatic steering angle command value θ ＡＤ per predetermined time is greater than or equal to a predetermined value. In the present embodiment, whether the automatic steering angle command value θ ＡＤ has suddenly changed or not is determined based on whether the absolute value of a change amount |Δθ ＡＤ between the automatic steering angle command value θ ＡＤ in a previous calculation cycle and the automatic steering angle command value θ ＡＤ | in a current calculation cycle is greater than or equal to a predetermined value α. α is a real number greater than 0. If |Δθ ＡＤ | ≧ α, it is determined that the automatic steering angle command value θ ＡＤ has suddenly changed; and if |Δθ ＡＤ | < α, it is determined that the automatic steering angle command value θ ＡＤ has not suddenly changed.

[0051] In the present embodiment, when it is determined that the automatic steering angle command value θ ＡＤ has not suddenly changed, a manual steering angle command value calculation unit 55 calculates the manual steering angle command value θ ＭＤ using a reference EPS model.

[0052] FIG. 3 is a schematic diagram illustrating an example of a reference EPS model used in the manual steering angle command value calculation unit 55. The reference EPS model in FIG. 3 is an example of "the reference model of a steering device" in the present disclosure. This reference EPS model is a single inertia model including a lower column. The lower column corresponds to an output shaft 9 and a worm wheel 21. However, this model is merely an example, and may be an inertia model including configurations other than those described above (for example, a rack shaft). In FIG. 3, J ｃ is inertia of the lower column (hereinafter referred to as "column inertia"), θ ｃ is a rotation angle of the lower column, and T ｔｂ is torsion bar torque. The torsion bar torque T ｔｂTorque N.T acting from the electric motor 18 to the output shaft 9 ｍ and road surface reaction torque (virtual reaction force) T ｒｌ T is given. ｍ This is the motor torque of the electric motor 18.

[0053] Road surface reaction torque T ｒｌ This is the spring constant of the virtual spring (hereinafter referred to as "virtual spring constant k") ＭＤ " and the viscous damping coefficient of the virtual damper (hereinafter referred to as "virtual viscous damping coefficient c") ＭＤ It is expressed by the following equation (1) using the virtual spring constant k. ＭＤ and virtual viscous damping coefficient c ＭＤ This has been determined in advance through experiments, analyses, etc.

[0054]

[0055] The equations of motion for the reference EPS model are given by equation (2) below. In equation (2), J ｃ d ２ θ ｃ / dt ２ This is the moment of inertia acting on the lower column.

[0056]

[0057] The manual steering angle command value calculation unit 55 is T ｔｂ Torsion bar torque T detected by torque sensor 12 ｔｂ Substitute T ｍ The assist torque command value T is set by the assist torque command value setting unit 54. ａｓ By substituting and solving the differential equation (2), we can find the rotation angle θ of the lower column. ｃ The manual steering angle command value calculation unit 55 then calculates the rotation angle θ of the lower column obtained. ｃ The manual steering angle command value θ ＭＤ Set it as follows.

[0058] In other words, the automatic steering angle command value θ ＡＤ If it is determined that there has been no sudden change, the manual steering angle command value calculation unit 55 calculates T in equation (2). ｍ to T ａｓReplace it with, and also with θ in equation (2) ｃ θ ＭＤ By solving the differential equation (3) below, with the substitution θ, the manual steering angle command value θ can be obtained. ＭＤ Calculate k. ＭＤ θ ＭＤ This may also be called a virtual spring reaction force. Also, c ＭＤ ・(dθ) ＭＤ The force ( / dt) may also be called the virtual damper reaction force.

[0059]

[0060] Auto steering angle command value θ ＡＤ If it is determined that the steering angle has changed suddenly, in this embodiment, the manual steering angle command value calculation unit 55 calculates the manual steering angle command value θ based on the following equation (4). ＭＤ Perform the calculation.

[0061]

[0062] In other words, the automatic steering angle command value θ ＡＤ If it is determined that the steering angle has changed suddenly, the manual steering angle command value calculation unit 55 calculates the current actual steering angle θ. ｐ From the current auto steering angle command value θ ＡＤ The value obtained by subtracting this value is the manual steering angle command value θ. ＭＤ Set it as follows.

[0063] In other words, the manual steering angle command value calculation unit 55 calculates the manual steering angle command value θ by, in principle, solving the differential equation (3) above. ＭＤ The automatic steering angle command value θ is calculated. ＡＤ If it is determined that the value has changed abruptly, the initial value of the solution to the differential equation (3) above is (θ ｐ -θ ＡＤ Set it to ).

[0064] The effects of the first embodiment will now be described. When the steering mode is set to manual steering mode, the first switch 58 is turned on and the second switch 59 is turned off. When the steering mode is set to coordinated steering mode, the first switch 58 is turned off and the second switch 59 is turned on. In other words, this motor control ECU 202 makes it possible for the driver to switch the steering mode between manual steering mode and coordinated steering mode by operating the mode switches 31 and 32.

[0065] When the steering mode is set to cooperative steering mode, the following situation is assumed: The higher-level ECU 201 receives the automatic steering angle command value θ. ＡＤ Regarding this, initially a positive (left) value is output, and then at a predetermined point in the middle (hereinafter referred to as "θ") ＡＤ This is called the "switching point." At this point, the value switches to a negative (right) value. The driver keeps the steering wheel in the neutral position (0 degrees). The driver uses the automatic steering angle command value θ, not the actual road reaction torque. ＡＤ I feel a reaction torque, as if being pulled in that direction.

[0066] Under these circumstances, the conditions we want to satisfy are the following two conditions: • Condition 1: Actual steering angle θ ｐ The integrated angle command value θ ｃｍｄ (=θ) ＡＤ +θ ＭＤ By following the command value θ, the automatic steering angle command value θ ＡＤ Due to the sudden change, the actual steering angle θ ｐ We also want to suppress sudden changes. In other words, the automatic steering angle command value θ ＡＤ We want to prevent the steering wheel from rotating rapidly due to a sudden change in the temperature. • Second condition: θ ＡＤ The automatic steering angle command value θ at the time of switching. ＡＤ Actual steering angle θ ｐ Direction {(θ) ＡＤ -θ ｐ We want to reliably communicate to the driver, as a reaction force, that the sign of ) has switched.

[0067] To satisfy the first condition, the auto steering angle command value θ ＡＤ Limiting the amount of change, or the automatic steering angle command value θＡＤ One could gradually change the value. However, with that method, the reaction force is not transmitted correctly, and the second condition cannot be satisfied.

[0068] To satisfy the second condition, the auto steering angle command value θ ＡＤ The steering angle θ can be changed in a stepwise manner, but ｐ Because the condition changes suddenly, the first condition cannot be met.

[0069] Figure 4A shows θ ＡＤ The automatic steering angle command value θ changes in a step-like manner at the switching point t1. ＡＤ The input is then passed directly to the integrated angle command value calculation unit 56, and the manual steering angle command value calculation unit 55 calculates the manual steering angle command value θ based on the differential equation (3). ＭＤ When calculating θ, ＡＤ , θ ＭＤ and the actual steering angle θ ｐ This is a graph showing the change. In this case, the actual steering angle θ at time t1. ｐ The torque changes abruptly, and the torque felt by the driver also changes abruptly.

[0070] Figure 4B shows the automatic steering angle command value θ at time t1. ＡＤ When the setting changes, the automatic steering angle command value θ ＡＤ The amount of change is limited, and the manual steering angle command value calculation unit 55 calculates the manual steering angle command value θ based on the differential equation (3). ＭＤ When calculating θ, ＡＤ , θ ＭＤ and the actual steering angle θ ｐ This graph shows the changes. In Figure 4B, the upward or downward arrows indicate the reaction torque felt by the driver. The same applies to Figure 4C.

[0071] In this case, the actual steering angle θ ｐ The value remains unchanged from 0 degrees, and the driver can maintain steering at 0 degrees. However, as shown in Figure 4B, the automatic steering angle command value θ ＡＤ During the change limit at the time of switching, the driver feels a reaction torque that pulls them to the left. In other words, the driver feels a reaction torque in the opposite direction to what the driver assistance system intended. Also, the automatic steering angle command value θ ＡＤIf you release your hands while the amount of change limit is being reached during the switchover, steering wheel 2 may turn to the left once. In other words, the automatic steering angle command value θ ＡＤ During the change limit at the time of switching, the actual steering angle θ ｐ This could result in an angle that is contrary to the intention of the driver assistance system.

[0072] Figure 4C shows θ when control is performed according to the first embodiment. ＡＤ , θ ＭＤ and the actual steering angle θ ｐ This graph shows the change in the automatic steering angle command value θ at time t1. ＡＤ When the switch occurs, the manual steering angle command value calculation unit 55 calculates the actual steering angle θ ｐ From the automatic steering angle command value θ ＡＤ The value obtained by subtracting this value is the manual steering angle command value θ. ＭＤ It is calculated as follows: that is, the automatic steering angle command value θ. ＡＤ The sudden change in the value is measured by the manual steering angle command value θ. ＭＤ This is absorbed by changing the value. As a result, the integrated angle command value θ is finally input to the angle control unit 57. ｃｍｄ (=θ) ＡＤ +θ ＭＤ This results in a smoother value, preventing sudden steering maneuvers.

[0073] Also, the automatic steering angle command value θ ＡＤ When the setting changes, even if you release the steering wheel, the automatic steering angle command value θ from before the change will remain. ＡＤ The steering wheel 2 will not rotate to the side. Furthermore, the automatic steering angle command value θ ＡＤ The moment the switch occurs, the reaction torque also switches, allowing the driver to correctly understand the intentions of the driver assistance system.

[0074] In other words, in the first embodiment, the automatic steering angle command value θ ＡＤ If the steering angle changes suddenly, ｐ This prevents sudden changes in the steering angle command value θ. ＡＤ This sudden change can prevent the steering wheel 2 from rotating rapidly. In the first embodiment, the automatic steering angle command value θ ＡＤ The value suddenly changed, and the automatic steering angle command value θ ＡＤActual steering angle θ ｐ When the direction changes, the automatic steering angle command value θ is set at the time of the change. ＡＤ Actual steering angle θ ｐ This allows the driver to reliably receive a reaction force indicating a change in direction.

[0075] Figure 5 is a schematic diagram showing the general configuration of a steering system to which a motor control device according to the second embodiment of this disclosure is applied. The steering system 101 includes a steering wheel (handle) 102 as a steering member for steering the vehicle, a steering mechanism 104 for steering the steering wheels 103, and a steering shaft 105 connected to the steering wheel 102. However, there is no mechanical connection between the steering shaft 105 and the steering mechanism 104 that transmits movements such as torque or rotation.

[0076] The steering shaft 105 includes a first shaft 107 with one end connected to the steering wheel 102, a torsion bar 108 with one end connected to the other end of the first shaft 107, and a second shaft 109 with one end connected to the other end of the torsion bar 108.

[0077] A torque sensor 111 is positioned near the torsion bar 108. The torque sensor 111 determines the torsion bar torque T applied to the steering wheel 102 based on the relative rotational displacement of the first shaft 107 and the second shaft 109. ｔｂ The torsion bar torque T detected by the torque sensor 111 is detected. In this embodiment, the torsion bar torque T is detected by the torque sensor 111. ｔｂ For example, the torque for steering to the left is detected as a positive value, and the torque for steering to the right is detected as a negative value, and the larger the absolute value, the greater the torsion bar torque T. ｔｂ Assume that the size of will increase.

[0078] A reaction motor 113 is connected to the second shaft 109 via a reduction gear 112 to control the rotation angle of the second shaft 109 (hereinafter sometimes referred to as the "actual steering angle"). The reaction motor 113 is an electric motor that applies a reaction torque to the second shaft 109. The reaction motor 113 is an example of an "electric motor capable of controlling the steering angle" in this disclosure.

[0079] The reduction gear 112 consists of a worm gear mechanism including a worm shaft (not shown) that is integrally rotatably connected to the output shaft of the reaction motor 113, and a worm wheel (not shown) that meshes with the worm shaft and is integrally rotatably connected to the second shaft 109. The reaction motor 113 is provided with a rotation angle sensor 114 for detecting the rotation angle of the reaction motor 113.

[0080] The steering mechanism 104 consists of a rack and pinion mechanism including a pinion shaft 115 and a rack shaft 116. Steering wheels 103 are connected to each end of the rack shaft 116 via tie rods 117 and knuckle arms (not shown). The pinion shaft 115 is connected to the output shaft of the steering motor 119 via a reduction gear 118. The reduction gear 118 consists of a worm gear mechanism including a worm shaft (not shown) that is integrally rotatably connected to the output shaft of the steering motor 119, and a worm wheel (not shown) that meshes with this worm shaft and is integrally rotatably connected to the pinion shaft 115. A pinion 115A is connected to the tip of the pinion shaft 115. The steering motor 119 is provided with a rotation angle sensor 120 for detecting the rotation angle of the steering motor 119.

[0081] In the following, the reduction ratio (gear ratio) of the reducer 112 is set to N １ This is expressed as N, and the reduction ratio of the reducer 118 is N ２ It is sometimes expressed as follows: The reduction ratio is the worm wheel angle θ, which is the rotation angle of the worm wheel. ｗｗ The worm gear angle θ is the rotation angle of the worm gear relative to the given value. ｗｇ The ratio θ ｗｇ / θ ｗｗ It is defined as follows.

[0082] The rack shaft 116 extends linearly along the left-right direction of the vehicle. A rack 116A is formed on the rack shaft 116, which meshes with the pinion 115A. When the steering motor 119 rotates, its rotational force is transmitted to the pinion shaft 115 via the reduction gear 118. Then, the rotation of the pinion shaft 115 is converted into axial movement of the rack shaft 116 by the pinion 115A and the rack 116A. As a result, the steering wheel 103 is steered.

[0083] The vehicle is equipped with a CCD camera 25, GPS 26, radar 27, and map information memory 28, similar to the first embodiment. The CCD camera 25, GPS 26, radar 27, and map information memory 28 are connected to a higher-level ECU 301 for performing driver assistance control and autonomous driving control. Similar to the higher-level ECU 201 in the first embodiment, the higher-level ECU 301 uses information obtained from the CCD camera 25, GPS 26, and radar 27, as well as map information obtained from the map information memory 28, to determine the automatic steering angle command value θ for automatic steering. ＡＤ Set it.

[0084] In this embodiment, the automatic steering angle command value θ ＡＤ This is expressed as the amount of rotation (rotation angle) of the pinion shaft 115 from the neutral position, with a positive value representing rotation in the left steering direction from the neutral position, and a negative value representing rotation in the right steering direction from the neutral position. The manual steering angle command value θ will be described later. ＭＤ This is expressed as the amount of rotation (angle of rotation) from the neutral position of the second axis 109, where a positive value represents the amount of rotation in the left steering direction from the neutral position, and a negative value represents the amount of rotation in the right steering direction from the neutral position.

[0085] The automatic steering angle command value θ is set by the higher-level ECU 301. ＡＤ This signal is transmitted to the reaction force ECU 302 and the steering ECU 303 via the in-vehicle network. The reaction force ECU 302 is an ECU for controlling the reaction force motor 113, and the steering ECU 303 is an ECU for controlling the steering motor 119.

[0086] Torsion bar torque T detected by torque sensor 111 ｔｂ The output signal from the rotation angle sensor 114 is input to the reaction force ECU 302. The reaction force ECU 302 controls the reaction force motor 113 based on these input signals and information provided by the higher-level ECU 301.

[0087] The output signal from the rotation angle sensor 120 is input to the steering ECU 303. The steering ECU 303 controls the steering motor 119 based on the output signal from the rotation angle sensor 120, information provided by the reaction force ECU 302, and information provided by the higher-level ECU 301.

[0088] Figure 6 is a block diagram illustrating the electrical configuration of the reaction force ECU 302 and the steering ECU 303. The reaction force ECU 302 includes a microcomputer 140, a drive circuit (inverter circuit) 131 controlled by the microcomputer 140 and supplying power to the reaction force motor 113, and the current (hereinafter referred to as "motor current I") that flows through the reaction force motor 113. ｒｍ It includes a current detection circuit 132 for detecting the following:

[0089] The microcomputer 140 is equipped with a CPU and memory (ROM, RAM, non-volatile memory, etc.) and functions as multiple function processing units by executing a predetermined program. These multiple function processing units include an assist torque command value setting unit 141, a manual steering angle command value calculation unit 142, a reaction force integrated angle command value calculation unit 143, a reaction force angle control unit 144, a rotation angle calculation unit 145, and a reduction ratio division unit 146.

[0090] The rotation angle calculation unit 145 calculates the rotor rotation angle θ of the reaction motor 113 based on the output signal of the rotation angle sensor 114. ｒｍ The reduction ratio division unit 146 calculates the rotor rotation angle θ. ｒｍ Reduction ratio N １ By dividing by θ, the rotor rotation angle θ ｒｍ The rotation angle (actual steering angle) θ of the second axis 109 ｒｐ Convert to this. The operation of the assist torque command value setting unit 141 is the same as the operation of the assist torque command value setting unit 54 in the first embodiment, so its explanation will be omitted.

[0091] The operation of the manual steering angle command value calculation unit 142 is substantially the same as the operation of the manual steering angle command value calculation unit 55 in the first embodiment. However, the lower column of the reference EPS model in Figure 3 corresponds, for example, to the second shaft 109 and the worm wheel of the reduction gear 112. In addition, the lower column has a torsion bar torque T detected by the torque sensor 111. ｔｂ Torque N acting from reaction motor 113 to second shaft 109 １ ・T ｍ and road surface reaction torque (virtual reaction force) T ｒｌ It is given.

[0092] The manual steering angle command value calculation unit 142 calculates the automatic steering angle command value θ ＡＤ When it is determined that there has been no sudden change, the manual steering angle command value θ is obtained by solving the differential equation (5) below, which is similar to equation (3) above. ＭＤ Perform the calculation.

[0093]

[0094] J in equation (5) ｃ For example, the inertia of the worm wheel of the second shaft 109 and the reduction gear 112 can be used. Also, the T in equation (5) ｔｂ For example, the torsion bar torque T detected by the torque sensor 111 in Figure 5 ｔｂ This is used. Also, T in equation (5) ａｓ The assist torque command value set by the assist torque command value setting unit 141 in Figure 6 is used.

[0095] The manual steering angle command value calculation unit 142 calculates the automatic steering angle command value θ ＡＤ When it is determined that the steering angle has changed suddenly, the current actual steering angle θ ｒｐ From the current auto steering angle command value θ ＡＤ The value obtained by subtracting (θ) ｒｐ -θ ＡＤ ) to the manual steering angle command value θ ＭＤ It is calculated as follows.

[0096] The integrated angle command value calculation unit 143 for reaction force calculates the automatic steering angle command value θ ＡＤ The manual steering angle command value θ is calculated by the manual steering angle command value calculation unit 142. ＭＤAdding this, the integrated angle command value θ for reaction force ｒｃｍｄ The integrated angle command value calculation unit 143 for reaction force is an example of the "integrated angle command value calculation unit" in this disclosure.

[0097] The reaction force angle control unit 144 sets the integrated reaction force angle command value θ. ｒｃｍｄ Based on this, the reaction force motor 113 is angle-controlled. More specifically, the reaction force angle control unit 144 controls the actual steering angle θ ｒｔ (The rotation angle of the second axis 109) is the integrated angle command value θ for reaction force. ｒｃｍｄ The drive circuit 131 is controlled to follow the movement.

[0098] As the reaction force angle control unit 144, a configuration can be used in which the rotation angle calculation unit (67) and the reduction ratio division unit (68) are removed from the reaction force angle control unit (45) shown in Figure 6 of Japanese Patent Application Publication No. 2020-132008 (Patent Document 2). The reason for removing the rotation angle calculation unit (67) and the reduction ratio division unit (68) is that the rotation angle calculation unit (67) and the reduction ratio division unit (68) correspond to the rotation angle calculation unit 145 and the reduction ratio division unit 146 in Figure 6 of this application, respectively. Note that θ in Figure 6 of Japanese Patent Application Publication No. 2020-132008 ｒｔ This is θ in Figure 6 of the present application. ｒｐ It corresponds to this.

[0099] The steering ECU 303 includes a microcomputer 180, a drive circuit (inverter circuit) 171 controlled by the microcomputer 180 that supplies power to the steering motor 119, and the current (hereinafter referred to as "motor current I") that flows through the steering motor 119. ｓｍ It includes a current detection circuit 172 for detecting the following:

[0100] The microcomputer 180 is equipped with a CPU and memory (ROM, RAM, non-volatile memory, etc.), and functions as multiple function processing units by executing a predetermined program. These multiple function processing units include a steering integrated angle command value calculation unit 181, a steering angle control unit 182, a rotation angle calculation unit 183, and a reduction ratio division unit 184.

[0101] The rotation angle calculation unit 183 calculates the rotor rotation angle θ of the steering motor 119 based on the output signal of the rotation angle sensor 120. ｓｍ The reduction ratio division unit 184 calculates the rotor rotation angle θ. ｓｍ Reduction ratio N ２ By dividing by θ, the rotor rotation angle θ ｓｍ The rotation angle (actual steering angle) of the pinion shaft 115 is θ ｓｐ Convert to.

[0102] The steering integrated angle command value calculation unit 181 calculates the automatic steering angle command value θ set by the higher-level ECU 301. ＡＤ The manual steering angle command value θ is calculated by the manual steering angle command value calculation unit 142 in the reaction force ECU 302. ＭＤ Adding this, the integrated steering angle command value θ ｓｃｍｄ Perform the calculation.

[0103] The steering angle control unit 182 controls the integrated steering angle command value θ. ｓｃｍｄ Based on this, the steering motor 119 is angle-controlled. More specifically, the steering angle control unit 182 controls the actual steering angle θ ｓｐ (The rotation angle of the pinion shaft 115) is the integrated steering angle command value θ ｓｃｍｄ The drive circuit 171 is controlled to follow the movement.

[0104] As the steering angle control unit 182, a configuration can be used in which the rotation angle calculation unit (97) and the reduction ratio division unit (98) are removed from the steering angle control unit (82) shown in Figure 7 of Japanese Patent Application Publication No. 2020-132008 (Patent Document 2). The reason for removing the rotation angle calculation unit (97) and the reduction ratio division unit (98) is that the rotation angle calculation unit (97) and the reduction ratio division unit (98) correspond to the rotation angle calculation unit 183 and the reduction ratio division unit 184 in Figure 6 of this application, respectively.

[0105] In the second embodiment, the same effects as in the first embodiment can be obtained. That is, in the second embodiment, the automatic steering angle command value θ ＡＤ If the steering angle changes suddenly, ｒｐ This prevents sudden changes in the steering angle command value θ. ＡＤThis prevents the steering wheel 102 from rotating rapidly due to a sudden change in the steering angle command value θ. In the second embodiment, the automatic steering angle command value θ ＡＤ The value suddenly changed, and the automatic steering angle command value θ ＡＤ Actual steering angle θ ｒｐ When the direction changes, the automatic steering angle command value θ is set at the time of the change. ＡＤ Actual steering angle θ ｒｐ This allows the driver to reliably receive a reaction force indicating a change in direction.

[0106] In the first and second embodiments described above, the automatic steering angle command value θ ＡＤ The determination of whether or not the steering angle has changed suddenly is made by the manual steering angle command value calculation unit 55, 142, which calculates the automatic steering angle command value θ ＡＤ This is done by determining whether the absolute value of the change per predetermined time is α or greater. However, the higher-level ECUs 201 and 301 determine the automatic steering angle command value θ ＡＤ When transmitting the motor control ECU 202 (or reaction force ECU 302), the automatic steering angle command value θ ＡＤ A determination signal indicating whether or not a sudden change has occurred may be sent to the motor control ECU 202 (or reaction force ECU 302).

[0107] In this case, the automatic steering angle command value θ comes from the higher-level ECUs 201 and 301. ＡＤ The judgment signal is then provided to the manual steering angle command value calculation units 55 and 142. The manual steering angle command value calculation units 55 and 142 calculate the automatic steering angle command value θ ＡＤ When a judgment signal indicating a sudden change is given from the higher-level ECUs 201 and 301, the automatic steering angle command value θ ＡＤ It is determined that the condition has suddenly worsened.

[0108] Figure 7 is a schematic diagram showing the general configuration of an electric power steering system to which the motor control device according to the third embodiment of this disclosure is applied. In Figure 7, parts corresponding to parts in Figure 1 are denoted by the same reference numerals as in Figure 1. Hereinafter, the act of a moving vehicle moving to an adjacent lane will be referred to as a "lane change".

[0109] The configuration of the electric power steering system 1A in Figure 7 is almost the same as the configuration of the electric power steering system 1 in Figure 1. However, the operation of the higher-level ECU 201A and the motor control ECU 202A differ from the operation of the higher-level ECU 201 and the motor control ECU 202 in Figure 1, respectively.

[0110] The upper-level ECU 201A sends the automatic steering angle command value θ to the motor control ECU 202A. ＡＤ and mode signal S ｍｏｄｅ In addition, Lane Change Flag F ＬＣ It is given.

[0111] The higher-level ECU 201A determines whether the driver intends to change lanes based on the driver's turn signal lever operation, vehicle position, etc. If it determines that the driver intends to change lanes, the higher-level ECU 201A sets an automatic steering angle command value θ. ＡＤ The automatic steering angle command value θ corresponds to the lane after the lane change. ＡＤ Switch to this.

[0112] Furthermore, if the higher-level ECU 201A determines that the driver intends to change lanes, it will activate the lane change flag F for a predetermined period of time from the time of determination until that time has elapsed (hereinafter referred to as the "lane change transition period"). ＬＣ Set (F ＬＣ =1) Do as follows. Except during the lane change transition period, the upper ECU 201A will set the lane change flag F. ＬＣ Reset (F ＬＣ Set to state =0. Lane change flag F ＬＣ The initial value is 0.

[0113] Figure 8 is a block diagram illustrating the electrical configuration of the motor control ECU 202A. In Figure 8, parts corresponding to each part in Figure 2 are denoted by the same reference numerals as in Figure 2. The motor control ECU 202A differs from the motor control ECU 202 in Figure 2 in the configuration of the microcomputer 50A. Specifically, the microcomputer 50A contains the automatic steering angle command value θ ＡＤ and lane change flag F ＬＣBased on , the final automatic steering angle command value θ ＡＤＦ is added a final automatic steering angle command value calculation unit 62 that calculates . In addition, the operation of the manual steering angle command value calculation unit 55A is different from the operation of the manual steering angle command value calculation unit 55 in FIG. 2. Other configurations inside the microcomputer 50A are the same as those of the microcomputer 50 in FIG. 2.

[0114] It should be noted that, as the angle control unit 57, a configuration obtained by removing the reduction ratio multiplication unit (68), the rotation angle calculation unit (69) and the reduction ratio division unit (70) from the angle control unit (54) shown in FIG. 5 of International Publication No. WO 2023 / 286169 (Patent Document 1) is used. The angle control unit (54) described in International Publication No. WO 2023 / 286169 includes a low-pass filter (51), a feedback control unit (66), a feedforward control unit (63), a disturbance torque estimation unit (64), and the like. The feedback control unit (66) includes an angle deviation calculation unit (62A) and a PD control unit (62B). The feedforward control unit (63) includes an angular acceleration calculation unit (63A) and an inertia multiplication unit (63B). However, in the following description, for convenience of explanation, it is assumed that the low-pass filter (51) is not provided. Hereinafter, the output of the feedback control unit (66) is referred to as "feedback control torque T ｆｂ ", and the output of the feedforward control unit (63) is referred to as "feedforward control torque T ｆｆ ".

[0115] The operation of the final automatic steering angle command value calculation unit 62 will be described. F ＬＣ = 0, the final automatic steering angle command value calculation unit 62 uses the automatic steering angle command value θ ＡＤ as the final automatic steering angle command value θ ＡＤＦ and outputs it as it is. When F ＬＣ = 1, that is, during the lane change transition period, the final automatic steering angle command value calculation unit 62 calculates and outputs the final automatic steering angle command value θ ＡＤＦ based on the following formula (6).

[0116]

[0117] In formula (6), θ ＡＤ＿ｂｅｆｏｒｅ is FＬＣ represents the automatic steering angle command value θ immediately before F changes from 0 to 1 ＡＤ . The final automatic steering angle command value calculation unit 62, for example, stores the previous value of automatic steering angle command value θ ＡＤ and when F ＬＣ changes from 0 to 1, sets the stored previous value of automatic steering angle command value θ ＡＤ as θ ＡＤ＿ｂｅｆｏｒｅ .

[0118] In the formula (6), α ＡＤ is the weight multiplied by the automatic steering angle command value θ ＡＤ and (1-α ＡＤ ) is the weight multiplied by θ ＡＤ＿ｂｅｆｏｒｅ . During a lane change transition period, the final automatic steering angle command value calculation unit 62 performs gradual change processing such as gradually increasing α ＡＤＦ from 0 to 1 so that the final automatic steering angle command value θ ＡＤ gradually approaches the automatic steering angle command value θ after the lane change ＡＤ .

[0119] When a lane change is performed, the automatic steering angle command value θ ＡＤ is switched from the automatic steering angle command value θ for the lane before the lane change ＡＤ＿ｂｅｆｏｒｅ to the automatic steering angle command value θ for the lane after the lane change ＡＤ . If this switching is performed in a stepwise manner, the motor torque command value will fluctuate significantly, which may increase the torque fluctuation perceived by the driver. Therefore, in order to suppress the torque fluctuation perceived by the driver during a lane change, when F ＬＣ = 1, the final automatic steering angle command value calculation unit 62 is configured to perform the aforementioned gradual change processing.

[0120] This makes it possible to suppress fluctuation of the motor torque command value during a lane change. On the other hand, the appropriate length of the lane change transition period varies depending on vehicle conditions and the driver. However, since the length of the lane change transition period is set to a fixed value, the length of the lane change transition period cannot be set to an appropriate length according to vehicle conditions and the driver, which may cause the driver to feel discomfort.

[0121] Therefore, in this third embodiment, even when the length of the lane change transition period is set to a constant value, a manual steering angle command value calculation unit 55A with the configuration shown in Figure 9 is used to mitigate the torque fluctuations felt by the driver.

[0122] In Figure 9, J ｃ This is column inertia. Column inertia J ｃ This consists, for example, of the inertia of the output shaft 9 and the worm wheel 21. ＭＤ c is a virtual spring constant and is pre-set. ＭＤ This is the virtual viscous damping coefficient, which is pre-set.

[0123] The manual steering angle command value calculation unit 55A includes a first addition / subtraction unit 401, a second addition / subtraction unit 402, an inertia division unit 403, a first integration unit 404, a second integration unit 405, a virtual damper reaction force calculation unit 406, a virtual spring reaction force calculation unit 407, a first addition unit 408, and a reduction ratio multiplication unit 409.

[0124] The second addition / subtraction unit 402 calculates the actual steering angle θ. ｐ From the final auto steering angle command value θ ＡＤＦ By subtracting (θ), ｐ -θ ＡＤＦ ) is calculated.

[0125] The reduction ratio multiplication unit 409 multiplies the assist torque command value T ａｓ By multiplying this by the reduction ratio N of the gearbox 19, the assist torque command value T, which corresponds to the output value of the electric motor 18, is obtained. ａｓ This corresponds to the assist torque command value N.T. which is the torque acting on the output shaft 9 (pinion shaft 13). ａｓ Convert to (the pinion shaft equivalent value of the motor torque of the electric motor 18).

[0126] The first addition unit 408 receives the virtual damper reaction force c from the virtual damper reaction force calculation unit 406. ＭＤ dθ ＭＤ / dt and the virtual spring reaction force k provided by the virtual spring reaction force calculation unit 407 ＭＤ θ ＭＤ By adding these together, the virtual load torque (virtual road surface load torque) T is obtained. ｌｏａｄ Perform the calculation.

[0127] The first addition / subtraction unit 401 is a torsion bar torque T ｔｂ Assist torque command value N・T ａｓ Add the values, and from the result of that addition, the virtual load torque T ｌｏａｄ Subtracting this, the first addition / subtraction unit 401 calculates the moment of inertia J on the left side of equation (3). ｃ d ２ θ ＭＤ / dt ２ (=T ｔｂ +N・T ａｓ -k ＭＤ θ ＭＤ -c ＭＤ dθ ＭＤ Calculate ( / dt).

[0128] The inertia division unit 403 calculates the moment of inertia J calculated by the first addition / subtraction unit 401. ＭＤ d ２ θ ＭＤ / dt ２ Column inertia J ｃ By dividing by θ, the manual steering angle command value θ ＭＤ The second derivative of d ２ θ ＭＤ / dt ２ Perform the calculation.

[0129] The first integrating unit 404 uses the manual steering angle command value θ. ＭＤ The second derivative of d ２ θ ＭＤ / dt ２ By integrating, the manual steering angle command value θ ＭＤ The first derivative dθ ＭＤ The calculation is performed by / dt. Specifically, the first integral unit 404 includes a first multiplication unit 411, a second addition unit 412, and a first delay unit 413. The first multiplication unit 411 is the manual steering angle command value θ ＭＤ The second derivative of d ２ θ ＭＤ / dt ２ Calculation period T ｓａｍｐ Multiply by . The first delay unit 413 outputs the output of the second adder unit 412 with a delay of one calculation period. The second adder unit 412 outputs the output T of the first multiplier unit 411. ｓａｍｐ d ２ θ ＭＤ / dt ２By adding the output of the first delay unit 413 (the previous value of the output of the second adder unit 412) to this, the manual steering angle command value θ ＭＤ The first derivative dθ ＭＤ The calculation is performed by / dt. In other words, the first integral unit 404 is T ｓａｍｐ d ２ θ ＭＤ / dt ２ The manual steering angle command value θ ＭＤ The first derivative dθ ＭＤ By adding the previous value of / dt, we obtain the current first derivative dθ. ＭＤ Calculate / dt.

[0130] The second integrating unit 405 controls the manual steering angle command value θ. ＭＤ The first derivative dθ ＭＤ By integrating / dt, the manual steering angle command value θ is obtained. ＭＤ The manual steering angle command value θ is calculated. ＭＤ The manual steering angle command value is output from the manual steering angle command value calculation unit 55A. Specifically, the second integration unit 405 includes a second multiplication unit 421, a third addition unit 422, a second delay unit 423, and a switching unit 424. The second multiplication unit 421 calculates the manual steering angle command value θ. ＭＤ The first derivative dθ ＭＤ / dt is the calculation period T ｓａｍｐ The result is multiplied by . The second delay unit 423 outputs the output of the third adder unit 422 with a delay of one calculation period.

[0131] The switching unit 424 receives the output of the second delay unit 423 (the previous value of the output of the third adder unit 422) and the output of the second addition / subtraction unit 402 (θ ｐ -θ ＡＤＦ ) is input. Switching unit 424 is Lane change flag F ＬＣ Based on the flag value, select one of those inputs and output it. Specifically, F ＬＣ When = 0, the switching unit 424 selects and outputs the output of the second delay unit 423. On the other hand, F ＬＣ When = 1, that is, during the lane change transition period, the switching unit 424 outputs (θ) of the second addition / subtraction unit 402. ｐ -θ ＡＤＦ Select ) and output.

[0132] The third adder 422 receives the output T of the second multiplier 421.ｓａｍｐ dθ ＭＤ By adding the output of the switching unit 424 to / dt, the manual steering angle command value θ is obtained. ＭＤ Calculate F ＬＣ When = 0, the third adder 422 is T ｓａｍｐ dθ ＭＤ / dt is the manual steering angle command value θ ＭＤ By adding the previous value, the manual steering angle command value θ ＭＤ Perform the calculation.

[0133] F ＬＣ When = 1, the third adder 422 is T ｓａｍｐ dθ ＭＤ / dt, manual steering angle command value θ ＭＤ Instead of the previous value of (θ ｐ -θ ＡＤＦ By adding ) the manual steering angle command value θ ＭＤ Perform the calculation.

[0134] The virtual damper reaction force calculation unit 406 calculates the manual steering angle command value θ calculated by the first integration unit 404. ＭＤ The first derivative dθ ＭＤ / dt is the virtual viscous damping coefficient c ＭＤ By multiplying by this, the virtual damper reaction force c ＭＤ dθ ＭＤ Calculate / dt. This virtual damper reaction force c ＭＤ dθ ＭＤ / dt is provided to the first adder 408.

[0135] The virtual spring reaction force calculation unit 407 calculates the manual steering angle command value θ calculated by the second integration unit 405. ＭＤ The virtual spring constant k ＭＤ By multiplying by this, the virtual spring reaction force k ＭＤ θ ＭＤ This is calculated. This virtual spring reaction force k ＭＤ θ ＭＤ This is applied to the first adding unit 408. Below, virtual spring reaction force k ＭＤ θ ＭＤ T ｓｐｒｉｎｇ It can sometimes be represented as follows.

[0136] In other words, the manual steering angle command value calculation unit 55A basically calculates the manual steering angle command value θ based on the equation of motion shown in equation (3) above. ＭＤ The calculation is performed. However, the lane change transition period (F ＬＣ During the period of =1, the manual steering angle command value θ ＭＤ Instead of the previous value, (θ ｐ -θ ＡＤＦ ) is used to obtain the manual steering angle command value θ ＭＤ This is calculated. This makes it possible to mitigate the torque fluctuations felt by the driver, even when the length of the lane change transition period is set to a constant value.

[0137] This point will be explained in more detail. A comparative example will be a configuration using a second integral unit that, instead of the second integral unit 405 of the third embodiment, provides the output of the second delay unit 423 to the third adder unit 422 without going through the switching unit 424. The behavior of the comparative example during lane changes is expressed by the following equations (7a), (7b), and (7c). This behavior is, in the third embodiment, F ＬＣ The behavior is the same as when the value is 0.

[0138]

[0139] To simplify the explanation, let's consider the behavior during lane changes with hands off the handlebars. In the comparative example, with hands off the handlebars, T ｔｂ = 0, T ａｓ = 0, T ｌｏａｄ = 0. Also, considering the static state when released, dθ ＭＤ Assuming the previous value of / dt is zero, the behavior during lane changes in the hands-free state in the comparative example is expressed by the following equations (8a), (8b), and (8c).

[0140]

[0141] Influence of the comparative example on angle control during lane changes (feedback control torque T) ｆｂ + Feedforward controlled torque T ｆｆ ) is expressed by the following equation (9), where the hands are released.

[0142]

[0143] In equation (9), k ０ is the proportional gain in feedback control. k １ is the derivative gain in feedback control. k ２ is the feedforward gain. k ０ , k １ and k ２ are represented by the following equation (10). In equation (10), ζ is the target damping coefficient of PD control. ω ｐｏｌｅ is the target response frequency of PD control.

[0144]

[0145] Behavior during lane change in the third embodiment (when F ＬＣ = 1) is represented by the following formulas (11a), (11b), (11c).

[0146]

[0147] In the third embodiment, in the hands-off state, T ｔｂ = 0, T ａｓ = 0. For simplicity of explanation, the virtual load torque T ｌｏａｄ during lane change in the third embodiment is assumed to be only the virtual spring reaction force (T ｐｒｉｎｇ = k ＭＤ ·θ ＭＤ ). In addition, in consideration of the static state when hands are off, the previous value of dθ ＭＤ / dt is regarded as zero. Furthermore, during lane change, since the absolute value of (θ ｐ - θ ＡＤＦ ) is larger than the absolute value of the term { - (T ｓａｍｐ ２ ) / J ｐｒｉｎｇ )·T ｃ ｓａｍｐ ２} containing T, the term { - (T ｓａｍｐ ２ ) / J ｐｒｉｎｇ )·T ｃ ｓａｍｐ ２} containing T is regarded as zero. Accordingly, in the third embodiment, during lane change in the hands-off state, T ｌｏａｄ = Tｓｐｒｉｎｇ = k ＭＤ (θ ｐ -θ ＡＤＦ ) Thus, the behavior during lane changes in the hands-free state in the third embodiment is expressed by the following equations (12a), (12b), and (12c).

[0148]

[0149] Influence of the third embodiment on angle control during lane changes (T ｆｂ +T ｆｆ ) is expressed by the following equation (13), where it is assumed that the hands are released.

[0150]

[0151] Comparing equation (9) and equation (13), the right-hand side (θ ＡＤＦ -θ ｐ The coefficients of (θ) in equation (13) are different. ＡＤＦ -θ ｐ Of the coefficients of ), the second term is 2ζ・ω ｐｏｌｅ ・k ＭＤ ・T ｓａｍｐ The value of is T ｓａｍｐ Since is small, the value is small. Also, (θ) in equation (13) ＡＤＦ -θ ｐ The first term of the coefficient of ) ＭＤ (θ) ＡＤＦ -θ ｐ k is the coefficient of ) ０ It is set to be smaller compared to the comparative example. Therefore, the sum of the feedforward control torque and the feedback control torque during lane changes is smaller in the third embodiment compared to the comparative example. For this reason, in the third embodiment, the final automatic steering angle command value θ during lane changes ＡＤＦ The responsiveness to the changes is lower compared to the comparative example. As a result, in the third embodiment, fluctuations in the torque command value during lane changes can be suppressed compared to the comparative example. This makes it possible to mitigate the torque fluctuations felt by the driver, even when the length of the lane change transition period is set to a constant value.

[0152] Figure 10 is a schematic diagram showing the general configuration of an electric power steering system to which a motor control device according to the fourth embodiment of this disclosure is applied. In Figure 10, parts corresponding to parts in Figure 1 are denoted by the same reference numerals as in Figure 1. The configuration of the electric power steering system 1B in Figure 10 is substantially the same as the configuration of the electric power steering system 1 in Figure 1. However, the operation of the higher-level ECU 201B and the motor control ECU 202B differ from the operation of the higher-level ECU 201 and the motor control ECU 202 in Figure 1, respectively.

[0153] The upper-level ECU 201B is connected to a CCD camera 25, GPS 26, radar 27, map information memory 28, first mode switch 31 and second mode switch 32, as well as a vehicle speed sensor 29 for detecting the vehicle speed V. The upper-level ECU 201B sends the automatic steering angle command value θ to the motor control ECU 202B. ＡＤ and mode signal S ｍｏｄｅ In addition, the vehicle speed V is given.

[0154] Figure 11 is a block diagram illustrating the electrical configuration of the motor control ECU 202B. In Figure 11, parts corresponding to the parts in Figure 2 are denoted by the same reference numerals as in Figure 2. The motor control ECU 202B differs from the motor control ECU 202 in Figure 2 in the configuration of the microcomputer 50B. The microcomputer 50B includes a rotation angle calculation unit 71, a first reduction ratio division unit 72, an assist control unit 73, a coordinated steering control unit 74, a combination unit 75, a second reduction ratio division unit 76, a torque control unit 77, and a steering mode determination / weight setting unit 78.

[0155] The operation of the rotation angle calculation unit 71, the first reduction ratio division unit 72, and the torque control unit 77 is the same as that of the rotation angle calculation unit 52, the first reduction ratio division unit 53, and the torque control unit 61 in Figure 2, respectively, so their explanation will be omitted.

[0156] The assist control unit 73 sets the assist torque command value T used in manual steering mode. ｐ１，ｃｍｄ The assist torque command value T is calculated. ｐ１，ｃｍｄThis is a torque command value (the pinion shaft equivalent value of the motor torque of the electric motor 18) that corresponds to the torque acting on the pinion shaft 13. As shown in Figure 12, the assist control unit 73 includes an axial force estimation unit 81, a lateral G calculation unit 82, a torsion bar torque command value setting unit 83, and a torque feedback control unit 84.

[0157] The axial force estimation unit 81 calculates the rack axial force estimate T based on, for example, the following equation (14). ｒａｃｋ The rack axial force estimate T is calculated. ｒａｃｋ In this embodiment, this is an estimated value of the pinion axis equivalent of the rack axial force, which is the force applied in the axial direction of the rack axis 14.

[0158]

[0159] In equation (14), T ｍ＿ｐｉｎｉｏｎ This is the pinion shaft equivalent value of the motor torque of the electric motor 18. In this embodiment, T ｍ＿ｐｉｎｉｏｎ This is not an actual measured value, but a target value (assist torque command value T). ｐ１，ｃｍｄ ) is used. J is the inertia of the electric power steering system 1B and is preset. For example, J is the inertia of the lower column (column inertia) including the output shaft 9 and the worm wheel 21. ｃ You may also use [this].

[0160] The axial force estimation unit 81 calculates the rack axial force estimate T based on, for example, the following equation (15). ｒａｃｋ You may also perform the calculation. In equation (15), c ＥＰ This is the viscous damping coefficient of the electric power steering system 1B, which is preset. ＥＰ This is the spring constant of the electric power steering system 1B, and is preset.

[0161]

[0162] The lateral G calculation unit 82 calculates the rack axial force estimate T calculated by the axial force estimation unit 81. ｒａｃｋ The lateral G (acceleration acting in the lateral direction) is determined based on the vehicle speed V. The lateral G calculation unit 82 calculates, for example, the rack axial force estimate T for each vehicle speed V. ｒａｃｋ The lateral G value for a given direction can be determined based on a stored map.

[0163] The torsion bar torque command value setting unit 83 sets the torsion bar torque command value (steering torque command value) T based on the lateral G calculated by the lateral G calculation unit 82. ｔｂ，ｃｍｄ Set the torsion bar torque command value T for lateral G. ｔｂ，ｃｍｄ An example of the settings is shown in Figure 13. Torsion bar torque command value T ｔｂ，ｃｍｄ This value is positive for positive lateral G values ​​and negative for negative lateral G values. Torsion bar torque command value T ｔｂ，ｃｍｄ The torsion bar torque command value T increases as the absolute value of lateral G increases. ｔｂ，ｃｍｄ The absolute value of is set to be large. The characteristic shown in Figure 13 is that the torsion bar torque command value T is relative to the absolute value of lateral G. ｔｂ，ｃｍｄ Although it has the characteristic of changing nonlinearly, the torsion bar torque command value T is relative to the absolute value of lateral G. ｔｂ，ｃｍｄ It may have the characteristic of changing linearly.

[0164] The torque feedback control unit 84 controls the torsion bar torque T ｔｂ Torsion bar torque command value T ｔｂ，ｃｍｄ Torque feedback control is performed to make it follow the torsion bar torque command value T. Specifically, the torque feedback control unit 84 controls the torsion bar torque command value T. ｔｂ，ｃｍｄ Torsion bar torque T ｔｂ The deviation from (T ｔｂ，ｃｍｄ -T ｔｂ By performing PD (proportional-derivative) calculation or PID (proportional-derivative-integral) calculation on ), the assist torque command value T is obtained. ｐ１，ｃｍｄ The assist torque command value T calculated by the torque feedback control unit 84 is calculated. ｐ１，ｃｍｄ This is supplied to the composite unit 75 (see Figure 11) and also to the axial force estimation unit 81.

[0165] Returning to Figure 11, the coordinated steering control unit 74 sets the coordinated torque command value T used in coordinated steering mode. ｐ２，ｃｍｄ The coordinated torque command value T is calculated. ｐ２，ｃｍｄThis is a torque command value (the pinion shaft equivalent value of the motor torque of the electric motor 18) that corresponds to the torque acting on the pinion shaft 13. As shown in Figure 14, the coordinated steering control unit 74 includes a manual steering angle command value generation unit 91, an integrated angle command value calculation unit 92, an angle feedback control unit 93, and a disturbance torque compensation unit 94.

[0166] The manual steering angle command value generation unit 91 basically generates a steering angle (more precisely, the rotation angle θ of the pinion shaft 13) corresponding to the steering wheel operation when the driver operates the steering wheel 2. ｐ ) to the manual steering angle command value θ ｍｄ It is provided for setting as follows. The manual steering angle command value generation unit 91 generates the torsion bar torque T detected by the torque sensor 12. ｔｂ Based on this, the manual steering angle command value θ ｍｄ Generates.

[0167] The manual steering angle command value generation unit 91 includes an assist torque command value setting unit 95 and a manual steering angle command value calculation unit 96. The assist torque command value setting unit 54 shown in Figure 2 can be used as the assist torque command value setting unit 95.

[0168] The manual steering angle command value calculation unit 96 calculates the torsion bar torque T detected by the torque sensor 12. ｔｂ The assist torque command value T set by the assist torque command value setting unit 95. ａｓ And the automatic steering angle command value θ ＡＤ And the actual steering angle θ ｐ And, the virtual spring constant k ＭＤ And the virtual viscous damping coefficient c ＭＤ Then, using the first flag F1 and the second flag F2 described later, the manual steering angle command value θ is determined. ＭＤ Generates a virtual spring constant k. ＭＤ and virtual viscous damping coefficient c ＭＤ This is pre-set. Details of the manual steering angle command value calculation unit 96 will be described later.

[0169] The integrated angle command value calculation unit 92 calculates the automatic steering angle command value θ ＡＤ The manual steering angle command value θ ＭＤ Adding this, the integrated angle command value θ ｃｍｄPerform the calculation.

[0170] The angle feedback control unit 93 controls the actual steering angle θ. ｐ The integrated angle command value θ ｃｍｄ Angle feedback control is performed to make it follow the movement. Specifically, the angle feedback control unit 93 controls the integrated angle command value θ. ｃｍｄ and the actual steering angle θ ｐ The deviation (θ) ｃｍｄ -θ ｐ By performing a PD (proportional-derivative) operation on ), the basic coordinated torque command value T is obtained. ｐ２，ｂｃｍｄ Perform the calculation.

[0171] The angle feedback control unit 93 controls the integrated angle command value θ. ｃｍｄ Then, the steering angle estimate ^θ calculated by the disturbance torque estimation unit 97, which will be described later, is calculated. ｐ The deviation (θ) ｃｍｄ -θ ｐ By performing PD calculations on ), the basic coordinated torque command value T ｐ２，ｂｃｍｄ You may perform the calculation.

[0172] The disturbance torque compensation unit 94 controls the basic coordinated torque command value T ｐ２，ｂｃｍｄ The system performs processing to remove the disturbance torque contained within it. The disturbance torque compensation unit 94 includes a disturbance torque estimation unit 97 and a subtraction unit 98.

[0173] The disturbance torque estimation unit 97 is provided to estimate the nonlinear torque (disturbance torque) that occurs as a disturbance in the plant (the object driven by the electric motor 18) during cooperative steering mode and during the slow change processing described later. In other words, the disturbance torque estimation unit 97 estimates the disturbance torque T, which is a torque other than the motor torque applied to the plant. ｌｃ It is established to estimate [the value of the

[0174] In this embodiment, the disturbance torque estimation unit 97 calculates the coordinated torque command value T ｐ２，ｃｍｄ and the actual steering angle θ ｐ Based on this, the disturbance torque T ｌｃ , steering angle θ ｐ and steering angular velocity (derivative value of steering angle) dθ ｐ The disturbance torque T / dt is estimated by the disturbance torque estimation unit 97. ｌｃ, steering angle θ ｐ and steering angular velocity dθ ｐ / dt represents the estimated disturbance torque ^T. ｌｃ , steering angle estimated value^θ ｐ and steering angular velocity estimate d^θ ｐ There are cases where it is written as / dt.

[0175] As the disturbance torque estimation unit 97, for example, the disturbance torque estimation unit (64) shown in Figure 5 of International Publication No. 2023 / 286169 (Patent Document 1) can be used. Note that the θ and N·T input to the disturbance torque estimation unit (64) in Figure 5 of International Publication No. 2023 / 286169 ｍ These are the θ values ​​that are input to the disturbance torque estimation unit 97 in Figure 14 of the present application. ｐ and T ｐ２，ｃｍｄ It corresponds to this.

[0176] The subtraction unit (disturbance torque removal unit) 98 calculates the basic coordinated torque command value T ｐ２，ｂｃｍｄ Estimated disturbance torque ^T ｌｃ By subtracting this, the coordinated torque command value T ｐ２，ｃｍｄ The calculation is performed. The coordinated torque command value T calculated by the subtraction unit 98. ｐ２，ｃｍｄ This is supplied to the disturbance torque estimation unit 97 and the synthesis unit 75 (see Figure 11).

[0177] Returning to Figure 11, the synthesis unit 75 includes a first weight multiplication unit 75A, a second weight multiplication unit 75B, and an addition unit 75C. The first weight multiplication unit 75A calculates the assist torque command value T calculated by the assist control unit 73. ｐ１，ｃｍｄ The first weight α is multiplied to the second weight multiplication unit 75B. ｐ２，ｃｍｄ The second weight (1-α) is multiplied by the second weight (1-α). The addition unit 75C multiplies the result of the first weight multiplication unit 75A, α・T. ｐ１，ｃｍｄ And the result of the second weight multiplication unit 75B (1-α)・T ｐ２，ｃｍｄ By adding these together, the final torque command value T is obtained. ｐ，ｃｍｄ (=α・T) ｐ１，ｃｍｄ + (1-α)・T ｐ２，ｃｍｄ ) is calculated. Final torque command value T ｐ，ｃｍｄ This is the torque command value for the pinion shaft 13.

[0178] The first weight α and the second weight (1-α) are set by the steering mode determination / weight setting unit 78. The steering mode determination / weight setting unit 78 receives the mode signal S from the higher-level ECU 201. ｍｏｄｅ and Torsion bar torque T ｔｂ The steering mode is determined based on this, and the first weight α and the second weight (1-α) are set based on the steering mode determination result.

[0179] The steering mode determination / weight setting unit 78, in principle, receives the steering mode signal S. ｍｏｄｅ The steering mode is determined based on the steering mode. However, if it is determined that an override operation has been performed by the driver when the steering mode is cooperative steering mode, the steering mode is determined to be manual steering mode, and a steering mode change command is sent to the higher-level ECU 201 to change the steering mode from cooperative steering mode to manual steering mode. When the higher-level ECU 201 receives the steering mode change command from the steering mode determination / weight setting unit 78, it changes the steering mode signal S from the signal representing cooperative steering mode to the signal representing manual steering mode. ｍｏｄｅ Change it.

[0180] In this embodiment, whether or not the driver overrides the operation is determined by the torsion bar torque T ｔｂ The determination is made based on the torsion bar torque T. Specifically, the steering mode determination / weight setting unit 78 determines the torsion bar torque T. ｔｂ If the absolute value of is greater than or equal to a predetermined threshold β (β > 0), it is determined that an override operation has occurred, and the torsion bar torque T ｔｂ If the absolute value of is less than β, it is determined that no override operation was performed.

[0181] In principle, the steering mode determination / weight setting unit 78 sets the first weight α to 1 (the second weight (1-α) to 0) if the steering mode determination result is manual steering mode, and sets the first weight α to 0 (the second weight (1-α) to 1) if the steering mode determination result is cooperative steering mode.

[0182] However, when switching steering modes, the steering mode determination / weight setting unit 78 gradually increases the first weight α from 0 to 1 or gradually decreases the first weight α from 1 to 0 in order to suppress fluctuations in motor torque. As a result, when switching steering modes, the assist torque command value T ｐ１，ｃｍｄ and coordinated torque command value T ｐ２，ｃｍｄ During this process, a gradual change is performed in which the torque command value corresponding to the steering mode before the switch is gradually reduced, and the torque command value corresponding to the steering mode after the switch is gradually increased.

[0183] Specifically, when the steering mode switches from manual steering mode to cooperative steering mode, the steering mode determination / weight setting unit 78 gradually decreases the first weight α from 1 to 0. On the other hand, when the steering mode switches from cooperative steering mode to manual steering mode, the steering mode determination / weight setting unit 78 gradually increases the first weight α from 0 to 1. In the following, the gradual change process performed when switching from manual steering mode to cooperative steering mode may be referred to as the first gradual change process, and the gradual change process performed when switching from cooperative steering mode to manual steering mode may be referred to as the second gradual change process.

[0184] Furthermore, the steering mode determination / weight setting unit 78 generates a first flag F1 and a second flag F2 and provides them to the manual steering angle command value calculation unit 96 in the cooperative steering control unit 74.

[0185] The steering mode determination / weight setting unit 78 sets the first flag F1 (F1=1) when the steering mode switches from manual steering mode to cooperative steering mode. After setting the first flag F1 (F1=1), the steering mode determination / weight setting unit 78 resets the first flag F1 (F1=0) in the next calculation cycle. The initial value of the first flag F1 is 0.

[0186] The steering mode determination / weight setting unit 78 sets the second flag F2 (F2 = 1) during the period in which the first gradual change process is being performed (hereinafter referred to as the "first transition period"). During periods other than the first transition period, the steering mode determination / weight setting unit 78 resets the second flag F2 (F2 = 0). The initial value of the second flag F2 is 0.

[0187] When the steering mode is coordinated steering mode, the integrated steering angle command value θ ｃｍｄ Actual steering angle θ ｐ Because it follows, θ ＡＤ +θ ＭＤ = θ ｐ However, the manual steering angle command value calculation unit 96 calculates the manual steering angle command value θ based on the same equation of motion as in equation (3). ＭＤ When calculating this, during the transition from manual steering mode to coordinated steering mode (first transition period), the manual steering angle command value θ is used when the proportion of coordinated steering mode is low (the value of α is large). ＭＤ The calculation is not performed correctly. Therefore, when the proportion of coordinated steering mode becomes sufficiently high, the final torque command value T ｐ，ｃｍｄ There is a risk of significant fluctuations.

[0188] In particular, when the steering mode switches from manual steering mode to coordinated steering mode while the driver is applying driver torque, even if the first gradual change process is performed, the final torque command value T ｐ，ｃｍｄ There is a risk of significant fluctuations. In other words, the torque fluctuations felt by the driver will be large. An example of a case where the steering mode switches from manual steering mode to coordinated steering mode while driver torque is applied is when the vehicle is traveling on a curved road and the steering mode switches from manual steering mode to coordinated steering mode.

[0189] By setting a longer first transition period, the torque fluctuations felt by the driver can be mitigated, but the start of automatic steering control (driving assistance control) is delayed, resulting in a delay in the automatic steering angle command value θ. ＡＤ The ability to follow the response to this will decrease.

[0190] Therefore, in this fourth embodiment, even if the first transition period is set to a relatively short period (for example, less than 1 sec), the manual steering angle command value calculation unit 96 shown in Figure 15 is used to mitigate the torque fluctuations felt by the driver. In Figure 15, the parts corresponding to the parts in Figure 9 are denoted by the same reference numerals as in Figure 9. Hereafter, the inertia J of the electric power steering system 1B will be referred to as the column inertia J ｃIt is assumed that the following is being used. Referring to Figure 15, the manual steering angle command value calculation unit 96 includes a first addition / subtraction unit 401, a second addition / subtraction unit 402A, an inertia division unit 403, a first integration unit 404A, a second integration unit 405A, a virtual damper reaction force calculation unit 406, a virtual spring reaction force calculation unit 407, a first addition unit 408, and a reduction ratio multiplication unit 409.

[0191] The operation of the second addition / subtraction unit 402A, the first integration unit 404A, and the second integration unit 405A differs from the operation of the second addition / subtraction unit 402, the first integration unit 404, and the second integration unit 405 in Figure 9. The second addition / subtraction unit 402A operates on the actual steering angle θ. ｐ From the automatic steering angle command value θ ＡＤ By subtracting (θ), ｐ -θ ＡＤ ) is calculated.

[0192] The first integrating unit 404A controls the manual steering angle command value θ. ＭＤ The second derivative of d ２ θ ＭＤ / dt ２ By integrating, the manual steering angle command value θ ＭＤ The first derivative dθ ＭＤ The calculation is performed by / dt. Specifically, the first integral unit 404A includes a first multiplication unit 411, a second addition unit 412, a first delay unit 413, and a first switching unit 414. The first multiplication unit 411 is the manual steering angle command value θ ＭＤ The second derivative of d ２ θ ＭＤ / dt ２ Calculation period T ｓａｍｐ Multiply by . The first delay unit 413 outputs the output of the second adder unit 412 with a delay of one calculation period.

[0193] The first switching unit 414 receives the output of the first delay unit 413 (the previous value of the output of the second adder unit 412) and 0 as inputs. Based on the flag value of the first flag F1, the first switching unit 414 selects one of these inputs and outputs it. Specifically, when F1 = 0, the first switching unit 414 selects and outputs the output of the first delay unit 413. On the other hand, when F1 = 1, the first switching unit 414 selects and outputs 0.

[0194] The second adder 412 receives the output T of the first multiplier 411.ｓａｍｐ d ２ θ ＭＤ / dt ２ By adding the output of the first switching unit 414 to this, the manual steering angle command value θ ＭＤ The first derivative dθ ＭＤ The calculation is performed by / dt. Specifically, when F1 = 0, the second adder 412 calculates T ｓａｍｐ d ２ θ ＭＤ / dt ２ The manual steering angle command value θ ＭＤ The first derivative dθ ＭＤ By adding the previous value of / dt, the manual steering angle command value θ is obtained. ＭＤ The first derivative dθ ＭＤ The current value of / dt is calculated. In contrast, when F1 = 1, the second adder 412 calculates T ｓａｍｐ d ２ θ ＭＤ / dt ２ The manual steering angle command value θ ＭＤ The first derivative dθ ＭＤ By adding 0 to the previous value of / dt, the manual steering angle command value θ is reduced. ＭＤ The first derivative dθ ＭＤ The current value of / dt is calculated. In this case, dθ is output from the first integrator 404A. ＭＤ / dt is dθ ＭＤ / dt = T ｓａｍｐ d ２ θ ＭＤ / dt ２ This is the result.

[0195] The second integrating unit 405A controls the manual steering angle command value θ. ＭＤ The first derivative dθ ＭＤ By integrating / dt, the manual steering angle command value θ is obtained. ＭＤ The manual steering angle command value θ is calculated. ＭＤ This is output from the manual steering angle command value calculation unit 96.

[0196] Specifically, the second integration unit 405A includes a second multiplication unit 421, a third addition unit 422, a second delay unit 423, and a second switching unit 424A. The second multiplication unit 421 is the manual steering angle command value θ. ＭＤ The first derivative dθ ＭＤ / dt is the calculation period T ｓａｍｐThe result is multiplied by . The second delay unit 423 outputs the output of the third adder unit 422 with a delay of one calculation period.

[0197] The second switching unit 424A receives the output of the second delay unit 423 (the previous value of the output of the third adder unit 422) and the output of the second addition / subtraction unit 402A (θ ｐ -θ ＡＤ ) is input. The second switching unit 424A switches these inputs based on the flag value of the second flag F2. Specifically, when F2 = 0, the second switching unit 424A selects and outputs the output of the second delay unit 423 (the previous value of the output of the third adder unit 422). On the other hand, when F2 = 1, the second switching unit 424A selects and outputs the output of the second addition / subtraction unit 402A (θ ｐ -θ ＡＤ Select ) and output.

[0198] The third adder 422 receives the output T of the second multiplier 421. ｓａｍｐ dθ ＭＤ By adding the output of the second switching unit 424A to / dt, the manual steering angle command value θ is obtained. ＭＤ The current value is calculated. Specifically, when F2 = 0, the third adder 422 calculates T ｓａｍｐ dθ ＭＤ / dt is the manual steering angle command value θ ＭＤ By adding the previous value, the manual steering angle command value θ ＭＤ The calculation is performed. In contrast, when F2 = 1, the third adder 422 performs T ｓａｍｐ dθ ＭＤ / dt, manual steering angle command value θ ＭＤ Instead of the previous value, (θ ｐ -θ ＡＤ By adding ) the manual steering angle command value θ ＭＤ We calculate the current value.

[0199] The manual steering angle command value calculation unit 96 basically calculates the manual steering angle command value θ based on the equation of motion shown in equation (3). ＭＤ The following is calculated. However, during the transition from manual steering mode to coordinated steering mode (first transition period), when the proportion of coordinated steering mode is low (the value of α is large), the manual steering angle command value θ ＭＤThe calculation is not performed correctly. Therefore, when the steering mode switches from manual steering mode to coordinated steering mode (when F1 = 1), the first integrating unit 404A calculates the manual steering angle command value θ. ＭＤ The first derivative dθ ＭＤ The previous value of / dt is replaced with 0. In other words, the accumulated integral value up to that point is reset to 0. Also, during the first transition period (the period when F2 = 1), the second integrator 405A controls the manual steering angle command value θ. ＭＤ Instead of the previous value of (θ ｐ -θ ＡＤ Using the manual steering angle command value θ, ＭＤ This calculates the manual steering angle command value θ. ＭＤ Using the previous value, the manual steering angle command value θ ＭＤ A more appropriate manual steering angle command value θ than when calculating it. ＭＤ This allows for the calculation of torque fluctuations felt by the driver during the first transition period, even when the first transition period is set to a short duration.

[0200] In the fourth embodiment described above, the first integrator 404A includes a first switching unit 414, but the first integrator 404A does not necessarily have to include a first switching unit 414. In that case, the second adder 412 is supplied with the output of the multiplier 411 and the output of the delay unit 413. In that case, the first flag F1 is not required.

[0201] While embodiments of this disclosure have been described in detail, these are merely examples used to illustrate the technical content of this disclosure, and this disclosure should not be construed as being limited to these examples. The scope of this disclosure is limited only to the attached claims.

[0202] 18...Electric motor, 54, 95...Assist torque command value setting unit, 55, 55A, 96...Manual steering angle command value calculation unit, 56...Integrated angle command value calculation unit, 57...Angle control unit, 58...First switch, 59...Second switch, 60...Addition unit, 61...Torque control unit, 62...Final automatic steering angle command value calculation unit, 73...Assist control unit, 74...Coordinated steering control unit, 75...Combination unit, 78...Steering mode determination / weight setting unit, 113...Reaction force motor, 141...Assist torque command value setting unit, 142...Manual steering angle command value calculation unit, 143...Integrated angle command value calculation unit for reaction force, 144...Angle control unit for reaction force, 402, 402A...Second addition / subtraction unit, 404, 404A...First integration unit, 405, 405A...Second multiplication unit, 414, 424, 424A...Switching unit

Claims

1. A motor control device for driving and controlling an electric motor capable of controlling the steering angle of a steering device, comprising: a manual steering angle command value calculation unit that calculates a manual steering angle command value by solving a differential equation that is, in principle, the equation of motion of the reference model of the steering device, using steering torque; an integrated angle command value calculation unit that calculates an integrated angle command value based on the automatic steering angle command value and the manual steering angle command value; and a control unit capable of controlling the electric motor based on the integrated angle command value, wherein the manual steering angle command value calculation unit resets the initial value of the solution to the differential equation using a value obtained by subtracting the automatic steering angle command value from the actual steering angle when predetermined conditions are met.

2. The motor control device according to claim 1, wherein the condition is determined to be that the automatic steering angle command value has changed abruptly.

3. The motor control device according to claim 2, wherein the manual steering angle command value calculation unit determines that the condition is met when the absolute value of the amount of change of the automatic steering angle command value per predetermined time is equal to or greater than a predetermined value.

4. The motor control device according to claim 2, wherein the higher-level ECU provides the manual steering angle command value calculation unit with the automatic steering angle command value and a determination signal indicating whether or not the automatic steering angle command value has changed abruptly, and the manual steering angle command value calculation unit determines whether or not the condition has been met based on the determination signal from the higher-level ECU.

5. The motor control device according to claim 1, comprising a final automatic steering angle command value calculation unit that calculates a final automatic steering angle command value based on the automatic steering angle command value, wherein when it is determined that a lane change has been performed, the final automatic steering angle command value calculation unit is configured to perform a gradual change process so that the final automatic steering angle command value gradually approaches the automatic steering angle command value after the lane change, and the condition is that the gradual change process is being executed.

6. A motor control device according to claim 1, comprising: an assist control unit that calculates an assist torque command value used in manual steering mode; a cooperative steering control unit that calculates a cooperative torque command value used in cooperative steering mode, which corresponds to the integrated angle command value; and a combining unit that calculates a final torque command value by adding a value obtained by multiplying the assist torque command value by a first weight corresponding to the steering mode and a value obtained by multiplying the cooperative torque command value by a second weight corresponding to the steering mode, wherein the control unit is configured to control the electric motor based on the final torque command value, and when switching modes from manual steering mode to cooperative steering mode, the first weight and the second weight are controlled to gradually decrease the assist torque command value and gradually increase the cooperative torque command value, wherein the condition is that the gradually increasing process is being executed.

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