Motor control device

Abstract

This motor control device comprises: a warning determination unit that determines, on the basis of detection information about an obstacle on the side of a vehicle, whether or not to apply a warning torque for preventing a collision of the vehicle with the obstacle; a warning torque calculation unit that calculates a warning torque when the warning determination unit determines that the warning torque should be applied; and a control unit that controls an electric motor so that the warning torque calculated by the warning calculation unit acts as a steering reaction force.

Description

Motor control device

[0001] The present disclosure relates to a control device for an electric motor for steering angle control.

[0002] The following Patent Document 1 discloses a parking assistance device that executes a driving assistance process to assist a vehicle in driving to a target parking position, and executes a collision avoidance process if an obstacle is detected during the driving assistance process. The parking assistance device described in Patent Document 1 is characterized by obtaining a target driving route that minimizes the possibility of assistance interruptions and is as slow as possible.

[0003] In the vehicle information display device described in Patent Document 2, a side monitoring sensor detects information (distance, direction, and relative speed) about vehicles and obstacles present to the sides of the vehicle. Then, based on this information, a risk to the sides of the vehicle is determined. For example, if it is determined that there is a high risk of the rear vehicle contacting the vehicle due to a sudden approach or lane change by a rear vehicle in an adjacent lane, a warning is displayed by the side warning display device. The vehicle information display device described in Patent Document 2 simply displays a warning when it is determined that there is a high risk to the sides of the vehicle.

[0004] JP 2021-62678 A JP 2003-291689 A International Publication No. 2023 / 286169

[0005] An object of the present disclosure is to provide a motor control device that can suppress a vehicle collision with an obstacle on the side of the vehicle using a novel method.

[0006] One embodiment of the present disclosure provides a motor control device for driving and controlling an electric motor of a steering device, the motor control device including: a warning determination unit that determines, based on detection information of an obstacle to the side of the vehicle, whether or not a warning torque should be applied to prevent the vehicle from colliding with the obstacle; a warning torque calculation unit that calculates the warning torque when the warning determination unit determines that a warning torque should be applied; and a control unit that controls the electric motor so that the warning torque calculated by the warning calculation unit acts as a steering reaction force.

[0007] This configuration makes it possible to suppress a collision of the vehicle with an obstacle on the side of the vehicle in a novel way.

[0008] The above and other objects, features, and advantages of the present disclosure will become apparent from the following description of the embodiments with reference to the accompanying drawings.

[0009] Fig. 1 is a schematic diagram showing the general configuration of an electric power steering system to which a motor control device according to an embodiment of the present disclosure is applied. Fig. 2 is a block diagram for explaining the electrical configuration of a motor control ECU. Fig. 3 is a diagram showing the torsion bar torque T ｔｂ Assist torque command value T ａｓ 11A is a schematic diagram showing an example of a trajectory (main trajectory prediction line) predicted when the vehicle is moving forward, and FIG. 11B is a schematic diagram showing an example of a trajectory (main trajectory prediction line) predicted when the vehicle is moving backward. FIG. 12A is a schematic diagram for explaining an example of a method for determining whether or not a first condition, that there is a high possibility of collision with a side obstacle, is satisfied when the vehicle is moving forward, and FIG. 12B is a schematic diagram for explaining an example of a method for determining whether or not the first condition is satisfied when the vehicle is moving backward. FIG. 13 shows θ in equation (11). ｓｔｐ，ＳＯＷ Actual steering angle θ when ｃ Warning torque T ＳＯＷ 14 is a graph showing the characteristics of θ ｓｔｐ，ＳＯＷ Actual steering angle θ when <0 ｃ Warning torque T ＳＯＷ15 is a flowchart showing the procedure of a first modified example of the side obstacle warning torque calculation process executed by the side obstacle warning torque calculation unit. FIG. 16 is a graph showing the characteristics of the first virtual steering angle G1·θ ｃ FIG. 17 is a schematic diagram for explaining that, when a collision determination region is set based on a main locus prediction line set using a trajectory prediction line, a state in which the first condition is satisfied and a state in which the first condition is not satisfied may repeatedly switch within a short period of time. FIG. 17 is a flowchart showing the procedure of a second modified example of the side obstacle warning torque calculation process executed by the side obstacle warning torque calculation unit. FIG. 18 is a schematic diagram for explaining the operation of the side obstacle warning torque calculation unit when the side obstacle warning torque calculation unit performs the side obstacle warning torque calculation process of FIG. 17. FIG. 19 is a block diagram showing a modified example of the manual steering command value calculation unit. FIG. 20 is a block diagram showing a modified example of the motor control ECU.

[0010] [Description of an embodiment of the present disclosure] One embodiment of the present disclosure provides a motor control device for driving and controlling an electric motor of a steering device, the motor control device including: a warning determination unit that determines, based on detection information of an obstacle to the side of the vehicle, whether or not a warning torque should be applied to prevent the vehicle from colliding with the obstacle; a warning torque calculation unit that calculates the warning torque when the warning determination unit determines that a warning torque should be applied; and a control unit that controls the electric motor so that the warning torque calculated by the warning calculation unit acts as a steering reaction force.

[0011] This configuration makes it possible to suppress a collision of the vehicle with an obstacle on the side of the vehicle in a novel way.

[0012] In one embodiment of the present disclosure, the warning determination unit determines that the warning torque should be applied when a condition is met in which the vehicle is highly likely to collide with the obstacle and the vehicle speed is equal to or less than a predetermined first threshold value, or a condition in which the vehicle is highly likely to collide with the obstacle and the torsion bar torque is equal to or greater than a predetermined second threshold value.

[0013] In one embodiment of the present disclosure, the warning determination unit determines that the warning torque should be applied when the following conditions are met: there is a high possibility that the vehicle will collide with the obstacle, the vehicle speed is equal to or less than a predetermined first threshold, and the torsion bar torque is equal to or greater than a predetermined second threshold.

[0014] In one embodiment of the present disclosure, the warning determination unit predicts the trajectory of the vehicle based on the actual steering angle, information indicating whether the vehicle is moving forward or backward, and the vehicle speed, and determines whether there is a high possibility that the vehicle will collide with the obstacle based on the prediction result.

[0015] In one embodiment of the present disclosure, the warning determination unit predicts the trajectory of the vehicle by regarding a virtual steering angle having an absolute value larger than that of the actual steering angle as an actual steering angle based on information indicating whether the vehicle is moving forward or backward, and the vehicle speed, and determines whether there is a high possibility that the vehicle will collide with the obstacle based on the prediction result.

[0016] In one embodiment of the present disclosure, the warning determination unit obtains a first prediction result by predicting a trajectory of the vehicle based on a first virtual steering angle having an absolute value larger than that of an actual steering angle, information indicating whether the vehicle is moving forward or backward, and a vehicle speed, by regarding the first virtual steering angle as an actual steering angle, and obtains a second prediction result by predicting a trajectory of the vehicle based on a second virtual steering angle having an absolute value larger than that of the first virtual steering angle, the information indicating whether the vehicle is moving forward or backward, and the vehicle speed, by regarding the second virtual steering angle as an actual steering angle.If the warning torque is not being applied, the warning determination unit determines whether the vehicle is likely to collide with the obstacle based on the first prediction result, and if the warning torque is being applied, the warning determination unit determines whether the vehicle is likely to collide with the obstacle based on the second prediction result.

[0017] In one embodiment of the present disclosure, the control unit includes a manual steering command value calculation unit that calculates a manual steering command value using a torsion bar torque, an integrated angle command value calculation unit that calculates an integrated angle command value by adding the manual steering command value to an automatic steering command value for driving assistance, and a first control unit for controlling the electric motor based on the integrated angle command value, wherein the manual steering command value is calculated by utilizing an equation of motion of a reference model of the steering device, and the warning torque is added to the equation of motion as a steering reaction force.

[0018] In one embodiment of the present disclosure, a limiting processing unit is provided that limits the absolute value of the torsion bar torque used in the calculation of the manual steering command value calculation unit to an upper limit value or less, and when the warning determination unit determines that the warning torque should be applied, the upper limit value is set to a value lower than the normal upper limit value.

[0019] In one embodiment of the present disclosure, the manual steering command value calculation unit is configured to calculate a manual steering command value based on the torsion bar torque and an assist torque command value calculated using the torsion bar torque, and the motor control device further includes a first limiting processing unit that limits the absolute value of the torsion bar torque used in the calculation of the manual steering command value calculation unit to be equal to or less than a first upper limit value, and a second limiting processing unit that limits the absolute value of the assist torque command value used in the calculation of the manual steering command value calculation unit to be equal to or less than a second upper limit value, and when the warning determination unit determines that the warning torque should be applied, the first upper limit value is set to a value lower than the first upper limit value under normal conditions, and the second upper limit value is set to a value lower than the second upper limit value under normal conditions.

[0020] In one embodiment of the present disclosure, the control unit includes an assist torque command value calculation unit that calculates an assist torque command value using a torsion bar torque, a subtraction unit that subtracts the warning torque from the assist torque command value, and a second control unit that controls the electric motor based on a result of the subtraction by the subtraction unit.

[0021] In one embodiment of the present disclosure, the system includes a first warning processing unit that performs a first warning processing to prevent the vehicle from colliding with a forward obstacle, which is an obstacle in front of the vehicle, based on detection information of the forward obstacle, and a second warning processing unit that performs a second warning processing to prevent the vehicle from colliding with the rear obstacle, which is an obstacle behind the vehicle, based on detection information of the rear obstacle, and if the first warning processing or the second warning processing is performed before it is determined that the warning torque should be applied, the warning torque is not applied as a steering reaction force.

[0022] DETAILED DESCRIPTION OF EMBODIMENTS OF THE PRESENT DISCLOSURE Hereinafter, embodiments of the present disclosure will be described in detail with reference to the accompanying drawings.

[0023] FIG. 1 is a schematic diagram showing a general configuration of an electric power steering system to which a motor control device according to an embodiment of the present disclosure is applied.

[0024] The electric power steering system 1 includes a steering wheel (handle) 2 as a steering member for steering the vehicle, a steering mechanism 4 that steers steered wheels 3 in conjunction with the rotation of the steering wheel 2, and a steering assist mechanism 5 that assists the driver in steering. The steering wheel 2 and the steering mechanism 4 are mechanically connected via a steering shaft 6 and an intermediate shaft 7.

[0025] The steering shaft 6 includes an input shaft 8 connected to the steering wheel 2 and an output shaft 9 connected to the intermediate shaft 7. The input shaft 8 and the output shaft 9 are connected via a torsion bar 10 so as to be capable of relative rotation.

[0026] A torque sensor 12 is disposed near the torsion bar 10. The torque sensor 12 detects the torsion bar torque (steering torque) T applied to the steering wheel 2 based on the amount of relative rotational displacement between the input shaft 8 and the output shaft 9. ｔｂ In this embodiment, the torsion bar torque T ｔｂFor example, the torque for steering left is detected as a positive value, and the torque for steering right is detected as a negative value. The larger the absolute value of the torque, the greater the torsion bar torque T ｔｂ The magnitude of is assumed to be large.

[0027] The steering mechanism 4 is made up of a rack-and-pinion mechanism including a pinion shaft 13 and a rack shaft 14 as a steering shaft. The steered wheels 3 are connected to each end of the rack shaft 14 via tie rods 15 and knuckle arms (not shown). The pinion shaft 13 is connected to the intermediate shaft 7. The pinion shaft 13 rotates in conjunction with the steering of the steering wheel 2. A pinion 16 is connected to the tip of the pinion shaft 13.

[0028] The rack shaft 14 extends linearly in the left-right direction of the vehicle. A rack 17 that meshes with the pinion 16 is formed in the axial middle of the rack shaft 14. The pinion 16 and the rack 17 convert the rotation of the pinion shaft 13 into axial movement of the rack shaft 14. By moving the rack shaft 14 in the axial direction, the steered wheels 3 can be steered.

[0029] When the steering wheel 2 is steered (rotated), this rotation is transmitted to the pinion shaft 13 via the steering shaft 6 and the intermediate shaft 7. The rotation of the pinion shaft 13 is then converted into axial movement of the rack shaft 14 by the pinion 16 and the rack 17. As a result, the steered wheels 3 are steered.

[0030] The steering assist mechanism 5 includes an electric motor 18 for generating a steering assist force (assist torque), and a reducer 19 for amplifying the output torque of the electric motor 18 and transmitting it to the steering mechanism 4. The reducer 19 is made up of a worm gear mechanism including a worm gear 20 and a worm wheel 21 that meshes with the worm gear 20. The reducer 19 is housed in a gear housing 22 that serves as a transmission mechanism housing.

[0031] In the following description, the reduction ratio (gear ratio) of the reducer 19 is represented by N. The reduction ratio N is expressed as a function of the worm wheel angle θ, which is the rotation angle of the worm wheel 21. ｗｗThe worm gear angle θ is the rotation angle of the worm gear 20 relative to the ｗｇ The ratio (θ ｗｇ / θ ｗｗ ) is defined as

[0032] The worm gear 20 is rotationally driven by the electric motor 18. The worm wheel 21 is connected to the output shaft 9 so as to be rotatable integrally therewith.

[0033] When the worm gear 20 is rotationally driven by the electric motor 18, the worm wheel 21 is rotationally driven, and motor torque is applied to the steering shaft 6, causing the steering shaft 6 (output shaft 9) to rotate. The rotation of the steering shaft 6 is then transmitted to the pinion shaft 13 via the intermediate shaft 7. The rotation of the pinion shaft 13 is converted into axial movement of the rack shaft 14, thereby turning the steered wheels 3. In other words, by rotating the worm gear 20 with the electric motor 18, steering assistance by the electric motor 18 and steering of the steered wheels 3 become possible. The electric motor 18 is provided with a rotation angle sensor 23 for detecting the rotation angle of the rotor of the electric motor 18.

[0034] The torque applied to the output shaft 9 includes the motor torque from the electric motor 18 and a disturbance torque T ｌｃ Disturbance torque other than the motor torque T ｌｃ Torsion bar torque T ｔｂ , road reaction torque (road load torque) T ｒｌ , friction torque T ｆ etc. are included.

[0035] Torsion bar torque T ｔｂ is the torque applied to the output shaft 9 from the steering wheel 2 side by the force applied to the steering wheel 2 by the driver, the force generated by steering inertia, etc.

[0036] Road reaction torque T ｒｌis the torque applied to the output shaft 9 from the steered wheels 3 side via the rack shaft 14 due to the self-aligning torque generated in the tire, the force generated by the suspension and tire / wheel alignment, the frictional force of the rack and pinion mechanism, etc.

[0037] The vehicle is equipped with a CCD (Charge Coupled Device) camera 25 that photographs the road ahead in the direction of travel of the vehicle, a GPS (Global Positioning System) 26 for detecting the vehicle's position, a radar 27 for detecting road shapes and obstacles, a map information memory 28 that stores map information, and a vehicle speed sensor 29 for detecting vehicle speed V.

[0038] The vehicle is further equipped with a side obstacle sensor 30 for detecting obstacles (hereinafter sometimes referred to as "side obstacles") that exist on the sides of the vehicle (including the diagonally forward and diagonally rearward sides). The sides of the vehicle include the left side of the vehicle, the diagonally forward left side of the vehicle, the diagonally rear left side of the vehicle, the right side of the vehicle, the diagonally forward right side of the vehicle, and the diagonally rear right side of the vehicle.

[0039] For example, a sonar for detecting a side obstacle is used as the side obstacle sensor 30. A CCD camera for detecting a side obstacle or a radar for detecting a side obstacle may also be used as the side obstacle sensor 30.

[0040] The vehicle is further equipped with two mode switches 31 and 32 for manually switching the steering mode.

[0041] As will be described later, the steering modes include a manual steering mode in which steering is performed by manual driving, and a cooperative steering mode in which steering based on both manual driving and automatic driving is possible.

[0042] The CCD camera 25, GPS 26, radar 27, and map information memory 28 are connected to a host ECU (Electronic Control Unit) 201 for performing driving assistance control and automatic driving control. Based on the information obtained by the CCD camera 25, GPS 26, and radar 27 and the map information, the host ECU 201 performs surrounding environment recognition, vehicle position estimation, route planning, etc., and determines control target values ​​for steering and drive actuators.

[0043] In this embodiment, the host ECU 201 controls the automatic steering command value θ ａｄ In this embodiment, the automatic steering control is, for example, a control for driving the vehicle along a target driving line. ａｄ is the target value of the steering angle for automatically driving the vehicle along the target driving line.

[0044] In this embodiment, the automatic steering command value θ ａｄ is expressed as the amount of rotation (rotation angle) of the output shaft 9 from the neutral position, and the amount of rotation from the neutral position in the left steering direction is expressed as a positive value, and the amount of rotation from the neutral position in the right steering direction is expressed as a negative value. ａｄ is set based on, for example, the vehicle speed, the lateral deviation from the target driving line (the center line of the lane), and the yaw deviation of the vehicle from the target driving line. ａｄ The process of setting the value is well known, so a detailed description will be omitted here.

[0045] The automatic steering control (driving assistance control) may be, for example, lane keeping assist (LKA) control, which assists in steering so that the vehicle stays within the driving lane, or lane centering assist (LCA) control, which assists in steering so that the vehicle stays in the center of the driving lane.

[0046] The host ECU 201 also detects a side obstacle based on the side obstacle sensor 30 and outputs the position coordinates of the detected side obstacle (hereinafter referred to as "side obstacle position coordinates X ｏｂｓ ,Y ｏｂｓ ") is calculated. The coordinate of the side obstacle position X ｏｂｓ ,Y ｏｂｓIn this embodiment, the coordinates of a plurality of points on the contour of the lateral obstacle in a planar view (coordinates on the contour) x ｏｂｓ ,y ｏｂｓ Contains x ｏｂｓ and y ｏｂｓ may be, for example, x- and y-coordinate values ​​in a vehicle coordinate system in which the width center line of the vehicle is the Y-axis and a straight line passing through the reference position of the vehicle and extending in the width direction of the vehicle is the X-axis. The reference position of the vehicle is set, for example, at a predetermined position on the width center line of the vehicle.

[0047] Furthermore, the host ECU 201 generates a steering mode signal S , which indicates whether the steering mode (driving mode) is a manual steering mode (manual driving mode) or a cooperative steering mode (driving assistance mode), based on the operation of the first mode switch 31 and the second mode switch 32. ｍｏｄｅ Specifically, when the first mode switch 31 is turned on by the driver, the host ECU 201 outputs a steering mode signal S ｍｏｄｅ On the other hand, when the second mode switch 32 is turned on by the driver, the host ECU 201 outputs a steering mode signal S ｍｏｄｅ Output.

[0048] Automatic steering command value θ ａｄ , the coordinate of the side obstacle position X ｏｂｓ ,Y ｏｂｓ , steering mode signal S ｍｏｄｅ , vehicle speed V and shift position information P ｓｈｉｆｔ is provided to the motor control ECU 202 via the in-vehicle network. ｓｈｉｆｔ is information indicating the current shift position such as Drive, Parking, Reverse, etc.

[0049] Torsion bar torque T detected by torque sensor 12 ｔｂ The output signal of the rotation angle sensor 23 is input to the motor control ECU 202. The motor control ECU 202 controls the electric motor 18 based on these input signals and information provided by the host ECU 201.

[0050] FIG. 2 is a block diagram for explaining the electrical configuration of the motor control ECU 202. As shown in FIG.

[0051] The motor control ECU 202 includes a microcomputer 50, a drive circuit (inverter circuit) 41 controlled by the microcomputer 50 to supply power to the electric motor 18, and a current (hereinafter, "motor current I") flowing through the electric motor 18. ｍ and a current detection circuit 42 for detecting the current.

[0052] The microcomputer 50 includes a CPU and memory (ROM, RAM, non-volatile memory, etc.), and functions as a plurality of functional processing sections by executing predetermined programs. The plurality of functional processing sections include an assist torque command value setting section 51, a side obstacle warning torque calculation section 52 (hereinafter referred to as the “warning torque calculation section 52”), a manual steering command value calculation section 53, an integrated angle command value calculation section 54, an angle control section 55, a first switch 56, a second switch 57, an adder 58, and a torque control section (current control section) 59.

[0053] The assist torque command value setting unit 51, the manual steering command value calculation unit 53, the integrated angle command value calculation unit 54, the angle control unit 55, the second switch 57, the adder 58, and the torque control unit 59 are an example of a "control unit" in the present disclosure. The angle control unit 55, the second switch 57, the adder 58, and the torque control unit 59 are an example of a "first control unit" in the present disclosure.

[0054] The assist torque command value setting unit 51 sets the assist torque command value T ａｓ The assist torque command value setting unit 51 sets the torsion bar torque T ｔｂ and the assist torque command value T ａｓ Set.

[0055] FIG. 3 shows the torsion bar torque T ｔｂ Assist torque command value T ａｓ 10 is a graph showing an example of setting the

[0056] Assist torque command value T ａｓ is set to a positive value when the electric motor 18 is to generate a steering assist force for steering to the left, and is set to a negative value when the electric motor 18 is to generate a steering assist force for steering to the right. ａｓ is the torsion bar torque T ｔｂ The torsion bar torque T ｔｂ The assist torque command value T ａｓ is the torsion bar torque T ｔｂ The larger the absolute value of , the larger the absolute value of , and the larger the vehicle speed V, the smaller the absolute value of .

[0057] The assist torque command value setting unit 51 calculates the torsion bar torque T ｔｂ is multiplied by a preset constant to obtain the assist torque command value T ａｓ may be calculated.

[0058] In the cooperative steering mode, the warning torque calculation unit 52 calculates the side obstacle position coordinate X ｏｂｓ ,Y ｏｂｓ , vehicle speed V and shift position information P ｓｈｉｆｔ and torsion bar torque T ｔｂ and the actual steering angle θ ｃ Based on this, a side obstacle warning torque (hereinafter referred to as "warning torque T") for suppressing a side collision of the vehicle with a side obstacle is calculated. ＳＯＷ ") is calculated.

[0059] Actual steering angle θ ｃ is the rotation angle of the output shaft 9, and is calculated based on the output signal of the rotation angle sensor 23, as will be described later. ｃ is expressed as the amount of rotation (rotation angle) of the output shaft 9 from the neutral position, where the amount of rotation from the neutral position in the left steering direction is expressed as a positive value, and the amount of rotation from the neutral position in the right steering direction is expressed as a negative value. Details of the warning torque calculation unit 52 will be described later.

[0060] When the driver operates the steering wheel 2 in the cooperative steering mode, the manual steering command value calculation unit 53 calculates a steering angle (more precisely, a rotation angle θ of the output shaft 9) corresponding to the steering wheel operation. ｃ ) is the manual steering command value θ ｍｄ However, in this embodiment, the manual steering command value calculation unit 53 also has a function of generating a steering reaction force to suppress a collision of the side of the vehicle with a lateral obstacle in the cooperative steering mode. Note that the manual steering command value calculation unit 53 is also provided to set the manual steering command value θ ｍｄ may be calculated.

[0061] The manual steering command value calculation unit 53 calculates the torsion bar torque T detected by the torque sensor 12. ｔｂ and the assist torque command value T set by the assist torque command value setting unit 51. ａｓ and the warning torque T set by the warning torque calculation unit 52. ＳＯＷ and the manual steering command value θ ｍｄ The manual steering command value calculation unit 53 will be described in detail later.

[0062] The integrated angle command value calculation unit 54 calculates the automatic steering command value θ set by the host ECU 201. ａｄ Manual steering command value θ ｍｄ The integrated angle command value θ ｃｍｄ Calculate the following.

[0063] The angle control unit 55 calculates an integrated angle command value θ ｃｍｄ Based on this, the integrated motor torque command value T ｃｏｍ The angle control unit 55 will be described in detail later.

[0064] The first switch 56 and the second switch 57 are connected to the steering mode signal S ｍｏｄｅ Specifically, the steering mode signal S indicates that the steering mode is the manual steering mode. ｍｏｄｅ is input, the first switch 56 is turned on and the second switch 57 is turned off.

[0065] On the other hand, the steering mode signal S ｍｏｄｅ is input, the first switch 56 is turned off and the second switch 57 is turned on.

[0066] When the first switch 56 is in the ON state and the second switch 57 is in the OFF state, the adder 58 calculates the assist torque command value T ａｓ , the motor torque command value T ｍ，ｃｍｄ (=T ａｓ On the other hand, when the second switch 57 is in the ON state and the first switch 56 is in the OFF state, the adder 58 outputs the integrated motor torque command value T ｃｏｍ The motor torque command value T ｍ，ｃｍｄ (=T ｃｏｍ ) is output.

[0067] The motor torque command value T ｍ，ｃｍｄ is given to the torque control section 59.

[0068] The torque control unit 59 controls the motor torque of the electric motor 18 to be equal to the motor torque command value T ｍ，ｃｍｄ The torque control unit 59 drives the drive circuit 41 so that the torque approaches the torque. Details of the torque control unit 59 will be described later.

[0069] The manual steering command value calculation unit 53 will now be described in detail.

[0070] First, the manual steering command value θ generated by the manual steering command value generating unit described in Patent Document 3 (WO 2023 / 286169) ｍｄ This section explains how to set this up.

[0071] The manual steering command value generating unit calculates the manual steering command value θ using the reference EPS model shown in FIG. ｍｄ The reference EPS model in FIG. 4 is an example of a "reference model of the steering device" in the present disclosure.

[0072] This reference EPS model is a single inertia model including a lower column. The lower column corresponds to the output shaft 9 and the worm wheel 21. However, this model is only an example, and an inertia model including a configuration other than the above (for example, a rack bar) may also be used. In FIG. 4, J ｍｄ is the inertia of the lower column (hereinafter referred to as "column inertia"), and θ ｃｏｌ is the rotation angle of the lower column, and T ｔｂ is the torsion bar torque. ｔｂ , torque N·T acting on the output shaft 9 from the electric motor 18 ｍ and road reaction torque (virtual reaction force) T ｒｌ is given.

[0073] Road reaction torque T ｒｌ is the spring constant k of the virtual spring ｍｄ and the viscous damping coefficient c of the virtual damper ｍｄ Using the above, it is expressed by the following equation (1).

[0074]

[0075] Spring constant k ｍｄ and the viscous damping coefficient c ｍｄ has been obtained in advance through experiments, analysis, etc. In the following, k ｍｄ ・θ ｃｏｌ is called the virtual spring reaction force, and c ｍｄ · (dθ ｃｏｌ / dt) is sometimes called a virtual damper reaction force.

[0076] The equation of motion of the reference EPS model is expressed by the following equation (2).

[0077]

[0078] In formula (2), J ｍｄ ・d ２ θ ｃｏｌ / dt ２ is the moment of inertia acting on the lower column.

[0079] The manual steering command value generating unit is T ｔｂ The torsion bar torque T detected by the torque sensor 12 ｔｂSubstituting, T ｍ The assist torque command value T ａｓ By substituting the above and solving the differential equation (2), the rotation angle θ of the lower column is obtained. ｃｏｌ Then, the manual steering command value generating unit calculates the obtained rotation angle θ of the lower column. ｃｏｌ The manual steering command value θ ｍｄ In this way, the manual steering command value θ ｍｄ The method of setting is called the comparison method.

[0080] The equation of motion in equation (2) is T ｍ T ａｓ and θ ｃｏｌ θ ｍｄ is equivalent to the equation of motion in which

[0081] In this embodiment, the manual steering command value calculation unit 53 calculates the manual steering command value θ using the equation of motion (2) of the reference EPS model described above. ｍｄ Specifically, in this embodiment, the manual steering command value calculation unit 53 calculates the manual steering command value θ based on the equation of motion obtained by modifying the equation of motion (2) of the reference EPS model described above. ｍｄ Calculate the following.

[0082] FIG. 5 is a block diagram showing the configuration of the manual steering command value calculation unit 53.

[0083] In FIG. ｍｄ is the column inertia. s is the differential operator. θ ｍｄ is the manual steering command value, and the rotation angle θ of the lower column in the comparison method ｃｏｌ Equivalent to: ｍｄ is the viscous damping coefficient of the virtual damper, which is determined in advance through experiments, analysis, etc. ｍｄ is the spring constant of the virtual spring, which is determined in advance by experiment, analysis, etc.

[0084] The manual steering command value calculation unit 53 includes a reduction ratio multiplication unit 101, an addition / subtraction unit 102, an inertia division unit 103, a first integration unit 104, a second integration unit 105, a virtual damper reaction force calculation unit 106, and a virtual spring reaction force calculation unit 107.

[0085] The reduction ratio multiplication unit 101 calculates the assist torque command value T ａｓ is multiplied by the reduction ratio N to obtain the assist torque command value T ａｓ is the assist torque command value N·T for the output shaft 9. ａｓ The assist torque command value N·T for the output shaft 9 calculated by the reduction ratio multiplication unit 101 is converted into ａｓ is given to the addition / subtraction unit 102.

[0086] The addition / subtraction unit 102 receives the torsion bar torque T ｔｂ and the assist torque command value N·T for the output shaft 9 calculated by the reduction ratio multiplication unit 101. ａｓ and warning torque T ＳＯＷ and the virtual damper reaction force c given by the virtual damper reaction force calculation unit 106 ｍｄ ・dθ ｍｄ / dt and the virtual spring reaction force k given by the virtual spring reaction force calculation unit 107 ｍｄ ・θ ｍｄ is input.

[0087] The addition / subtraction unit 102 calculates the torsion bar torque T ｔｂ Assist torque command value N·T for output shaft 9 ａｓ The result of the addition is used to calculate the warning torque T ＳＯＷ , virtual damper reaction force c ｍｄ ・dθ ｍｄ / dt and virtual spring reaction force k ｍｄ ・θ ｍｄ As a result, the adder / subtractor 102 subtracts J on the left side of the equation (2). ｍｄ ・d ２ θ ｃｏｌ / dt ２ The moment of inertia J corresponds to ｍｄ ・d ２ θ ｍｄ / dt ２ (=T ｔｂ +N.T. ａｓ -c ｍｄ ・dθ ｍｄ / dt-k ｍｄ ・θ ｍｄ -T ＳＯＷ ) is calculated.

[0088] The inertia division unit 103 divides the moment of inertia J calculated by the addition / subtraction unit 102. ｍｄ ・d ２ θ ｍｄ / dt ２ The column inertia J ｍｄ By dividing by , the manual steering command value θ ｍｄ The second derivative d ２ θ ｍｄ / dt ２ Calculate the following.

[0089] The first integration unit 104 calculates the manual steering command value θ ｍｄ The second derivative d ２ θ ｍｄ / dt ２ By integrating the manual steering command value θ ｍｄ The first derivative dθ ｍｄ / dt is calculated.

[0090] The second integration unit 105 calculates the manual steering command value θ ｍｄ The first derivative dθ ｍｄ By integrating / dt, the manual steering command value θ ｍｄ This manual steering command value θ ｍｄ is output from the manual steering command value calculation unit 53.

[0091] The virtual damper reaction force calculation unit 106 calculates the manual steering command value θ ｍｄ The first derivative dθ ｍｄ / dt with viscous damping coefficient c ｍｄ By multiplying by ｍｄ ・dθ ｍｄ / dt is calculated. This virtual damper reaction force c ｍｄ ・dθ ｍｄ / dt is fed back to the addition / subtraction unit 102 .

[0092] The virtual spring reaction force calculation unit 107 calculates the manual steering command value θ ｍｄ Spring constant k ｍｄ By multiplying by ｍｄ ・θ ｍｄ This virtual spring reaction force k ｍｄ ・θ ｍｄ is fed back to the addition / subtraction unit 102.

[0093] That is, the manual steering command value calculation unit 53 calculates the manual steering command value θ based on the equation of motion shown in the following equation (3). ｍｄ Calculate the following.

[0094]

[0095] In formula (3), J ｍｄ ・d ２ θ ｍｄ / dt ２ is the moment of inertia. N.T ａｓ is the assist torque command value for the output shaft 9. ｍｄ ・dθ ｍｄ / dt is the virtual damper reaction force. ｍｄ ・θ ｍｄ is the virtual spring reaction force. ＳＯＷ is the warning torque T ＳＯＷ is.

[0096] In this embodiment, the manual steering command value calculation unit 53 adds "-T" to the right side of the equation of motion in the above-mentioned formula (2). ＳＯＷ Based on the equation of motion to which " has been added, the manual steering command value θ ｍｄ This calculates the warning torque T ＳＯＷ This acts as a steering reaction force that suppresses steering (driver operation) in a direction that would cause the side of the vehicle to collide with a side obstacle. This suppresses the side of the vehicle from colliding with a side obstacle. This will be described in detail later.

[0097] In this embodiment, the assist torque command value N·T for the output shaft 9 is ａｓ is given to the adding / subtracting unit 102, and the assist torque command value N·T for the output shaft 9 ａｓ may not be given to the adding / subtracting unit 102. In this case, the adding / subtracting unit 102 calculates the torsion bar torque T ｔｂ From, warning torque T ＳＯＷ , virtual damper reaction force c ｍｄ ・dθ ｍｄ / dt and virtual spring reaction force k ｍｄ ・θ ｍｄ In this case, the manual steering command value calculation unit 53 subtracts "N.T" from the right side of the above equation (3). ａｓ」Based on the equation of motion from which is removed, the manual steering command value θ ｍｄ The following calculation is performed.

[0098] FIG. 6 is a block diagram showing the configuration of the angle control unit 55.

[0099] The angle control unit 55 calculates an integrated angle command value θ ｃｍｄ Based on this, the integrated motor torque command value T ｃｏｍ The angle control unit 55 includes a low-pass filter (LPF) 61, a feedback control unit 62, a feedforward control unit 63, a disturbance torque estimating unit 64, a torque adding unit 65, a disturbance torque compensating unit 66, a first reduction ratio dividing unit 67, a reduction ratio multiplying unit 68, a rotation angle calculating unit 69, and a second reduction ratio dividing unit 70.

[0100] The reduction ratio multiplication unit 68 multiplies the motor torque command value T ｍ，ｃｍｄ is multiplied by the reduction ratio N of the reducer 19 to obtain the motor torque command value T ｍ，ｃｍｄ is the output shaft torque command value N·T acting on the output shaft 9 (worm wheel 21). ｍ，ｃｍｄ Convert to.

[0101] The rotation angle calculation unit 69 calculates the rotor rotation angle θ of the electric motor 18 based on the output signal of the rotation angle sensor 23. ｍ The second reduction ratio division unit 70 calculates the rotor rotation angle θ calculated by the rotation angle calculation unit 69. ｍ By dividing by the reduction ratio N, the rotor rotation angle θ ｍ The rotation angle (actual steering angle) θ of the output shaft 9 ｃ Convert to.

[0102] The low-pass filter 61 calculates the integrated angle command value θ ｃｍｄ The integrated angle command value θ after low-pass filtering is ｃｍｄｌ is given to the feedback control section 62 and the feedforward control section 63. The low-pass filter 61 does not have to be provided.

[0103] The feedback control unit 62 calculates the steering angle estimated value ^θ calculated by the disturbance torque estimating unit 64. ｃis the integrated angle command value θ after low-pass filtering. ｃｍｄｌ The feedback control unit 62 includes an angle deviation calculation unit 62A and a PD control unit 62B. The angle deviation calculation unit 62A calculates an integrated angle command value θ ｃｍｄｌ and the estimated steering angle ^θ ｃ Deviation Δθ (= θ ｃｍｄｌ -^θ ｃ ) is calculated. The angle deviation calculation unit 62A calculates the integrated angle command value θ ｃｍｄｌ and the actual steering angle θ calculated by the second reduction ratio division unit 70. ｃ deviation from (θ ｃｍｄｌ -θ ｃ ) may be calculated as the angle deviation Δθ.

[0104] The PD control unit 62B performs a PD calculation (proportional differential calculation) on the angle deviation Δθ calculated by the angle deviation calculation unit 62A, thereby obtaining a feedback control torque T ｆｂ The feedback control torque T ｆｂ is given to the torque adder 65.

[0105] The feedforward control unit 63 is provided to compensate for a delay in response due to the inertia of the electric power steering system 1, thereby improving the response of the control. The feedforward control unit 63 includes an angular acceleration calculation unit 63A and an inertia multiplication unit 63B. The angular acceleration calculation unit 63A calculates an integrated angle command value θ ｃｍｄｌ By differentiating twice, the target angular acceleration d ２ θ ｃｍｄｌ / dt ２ Calculate the following.

[0106] The inertia multiplication unit 63B multiplies the target angular acceleration d calculated by the angular acceleration calculation unit 63A by ２ θ ｃｍｄｌ / dt ２ is multiplied by the inertia J of the electric power steering system 1 to obtain the feedforward control torque T ｆｆ (=J.d ２ θ ｃｍｄｌ / dt ２The inertia J can be calculated from, for example, a physical model (see FIG. 7) of the electric power steering system 1, which will be described later. The feedforward control torque T ｆｆ is given to the torque adder 65 as an inertia compensation value.

[0107] The torque adder 65 calculates the feedback control torque T ｆｂ The feedforward control torque T ｆｆ By adding ｆｂ +T ｆｆ ) is calculated.

[0108] The disturbance torque estimating unit 64 is provided to estimate a nonlinear torque (disturbance torque: torque other than motor torque) that occurs as a disturbance in the plant (the object to be controlled by the electric motor 18). The disturbance torque estimating unit 64 estimates the output shaft torque command value N·T ｍ，ｃｍｄ and the actual steering angle θ ｃ Based on this, the disturbance torque (disturbance load) T ｌｃ , steering angle θ and steering angle differential value (angular velocity) dθ ｃ / dt is estimated. ｌｃ , steering angle θ ｃ and steering angle differential value (angular velocity) dθ ｃ The estimated values ​​of / dt are respectively ｌｃ , ^θ ｃ and d^θ ｃ The disturbance torque estimation unit 64 will be described in detail later.

[0109] The disturbance torque estimated value ^T calculated by the disturbance torque estimator 64 ｌｃ is given to the disturbance torque compensator 66 as a disturbance torque compensation value. The steering angle estimated value ^θ calculated by the disturbance torque estimator 64 ｃ is given to the angle deviation calculation unit 62A.

[0110] The disturbance torque compensator 66 calculates the basic torque command value (T ｆｂ +T ｆｆ ) to the estimated disturbance torque value ^T ｌｃ By subtracting ｃｏ (=T ｆｂ +T ｆｆ -^Tｌｃ ) is calculated. As a result, the integrated torque command value T ｃｏ (torque command value for the output shaft 9) is obtained.

[0111] Integrated torque command value T ｃｏ is given to the first reduction ratio division unit 67. The first reduction ratio division unit 67 calculates the integrated torque command value T ｃｏ is divided by the reduction ratio N to obtain the integrated motor torque command value T ｃｏｍ (torque command value for the electric motor 18). This integrated motor torque command value T ｃｏｍ is applied to the second switch 57 (see FIG. 2).

[0112] The disturbance torque estimation unit 64 will be described in detail. The disturbance torque estimation unit 64 uses, for example, a physical model 300 of the electric power steering system 1 shown in FIG. 7 to estimate the disturbance torque T ｌｃ , steering angle θ ｃ and angular velocity dθ ｃ It is composed of a disturbance observer that estimates / dt.

[0113] This physical model 300 includes a plant (an example of a motor-driven object) 301 including an output shaft 9 and a worm wheel 21 fixed to the output shaft 9. The plant 301 receives a torsion bar torque T ｔｂ is applied, and a road reaction torque T ｒｌ is given.

[0114] Furthermore, the plant 301 receives an output shaft torque command value N·T via a worm gear 20. ｍ，ｃｍｄ is applied, and friction torque T ｆ is given.

[0115] When the inertia of the plant 301 is J, the equation of motion for the inertia of the physical model 300 is expressed by the following equation (4).

[0116]

[0117] d ２ θ ｃ / dt ２ is the angular acceleration of the plant 301. N is the reduction ratio of the reducer 19. T ｌｃ represents a disturbance torque other than the motor torque applied to the plant 301. In this embodiment, the disturbance torque T ｌｃ is the torsion bar torque T ｔｂ and road reaction torque T ｒｌ and friction torque T ｆ However, in reality, the disturbance torque T ｌｃ includes torques other than these.

[0118] The state equation for the physical model 300 in FIG. 7 is expressed by the following equation (5).

[0119]

[0120] In the above formula (5), x is the state variable vector, u １ is the known input vector, u ２ is the unknown input vector, y is the output vector (measurement value). In addition, in the above formula (5), A is the system matrix, B １ is the first input matrix, B ２ is the second input matrix, C is the output matrix, and D is the direct feedthrough matrix.

[0121] The state equation is expressed as follows: ２ The state equation of the extended system (extended state equation) is expressed by the following equation (6).

[0122]

[0123] In the formula (6), x ｅ is the state variable vector of the extended system, and is expressed by the following equation (7).

[0124]

[0125] In the formula (6), A ｅ is the system matrix of the extended system, B ｅ is the known input matrix of the extended system, C ｅ is the output matrix of the augmented system.

[0126] From the extended state equation of the above-mentioned equation (6), a disturbance observer (extended state observer) expressed by the following equation (8) is constructed.

[0127]

[0128] In equation (8), ^x ｅ Ha x ｅ represents the estimated value of . Also, L is the observer gain. Also, ^y represents the estimated value of y. ^x ｅ is expressed by the following equation (9).

[0129]

[0130] In equation (9), ^θ ｃ is θ ｃ is an estimate of ^T ｌｃ is T ｌｃ is an estimate of

[0131] The disturbance torque estimation unit 64 calculates the state variable vector ^x based on the equation (8). ｅ Calculate the following.

[0132] FIG. 8 is a block diagram showing the configuration of the disturbance torque estimating section 64.

[0133] The disturbance torque estimation unit 64 includes an input vector input unit 81, an output matrix multiplication unit 82, a first addition unit 83, a gain multiplication unit 84, an input matrix multiplication unit 85, a system matrix multiplication unit 86, a second addition unit 87, an integration unit 88, and a state variable vector output unit 89.

[0134] The output shaft torque command value N·T calculated by the reduction ratio multiplication unit 68 (see FIG. 6) ｍ，ｃｍｄ is given to the input vector input unit 81. The input vector input unit 81 receives the input vector u １ Output.

[0135] The output of the integrator 88 is the state variable vector ^x ｅ (See the above equation (9)). At the start of the calculation, the state variable vector ^x ｅ The initial value is given as the state variable vector ^x ｅ The initial value of is, for example, 0.

[0136] The system matrix multiplication unit 86 multiplies the state variable vector ^x ｅ system matrix A ｅ The output matrix multiplication unit 82 multiplies the state variable vector ^x ｅ into the output matrix C ｅ Multiply by.

[0137] The first adder 83 calculates the actual steering angle θ calculated by the second reduction ratio divider 70 (see FIG. 6). ｃ From the output vector (measurement value) y, the output of the output matrix multiplication unit 82 (C ｅ ・^x ｅ ) is subtracted from the output vector y. That is, the first adder 83 subtracts the output vector estimate ^y (=C ｅ ・^x ｅ The gain multiplication unit 84 multiplies the output (y−^y) of the first addition unit 83 by the observer gain L (see equation (8) above).

[0138] The input matrix multiplication unit 85 multiplies the input vector u output from the input vector input unit 81. １ Input matrix B ｅ The second adder 87 multiplies the output (B ｅ ・u １ ), and the output of the system matrix multiplication unit 86 (A ｅ ・^x ｅ ) and the output (L(y-^y)) of the gain multiplication unit 84, the differential value d^x of the state variable vector is obtained. ｅ The integrator 88 calculates the output of the second adder 87 (d^x ｅ / dt), the state variable vector ^x ｅ The state variable vector output unit 89 calculates the state variable vector ^x ｅ Based on this, the disturbance torque estimate ^T ｌｃ , steering angle estimate ^θ ｃ and the estimated angular velocity d^θ ｃ / dt is calculated.

[0139] Unlike the above-mentioned extended state observer, a general disturbance observer is composed of an inverse model of the plant and a low-pass filter. The equation of motion of the plant is expressed by equation (3) as described above. Therefore, the inverse model of the plant is expressed by the following equation (10).

[0140]

[0141] The input to a general disturbance observer is J·d ２ θ ｃ / dt ２ and N.T. ｍ，ｃｍｄ and the actual steering angle θ ｃ Since the second-order differential value of is used, it is significantly affected by noise from the rotation angle sensor 23. In contrast, the extended state observer of the above-described embodiment estimates the disturbance torque in an integral manner, so that it is possible to reduce the influence of noise due to differentiation.

[0142] The disturbance torque estimating unit 64 may be a general disturbance observer that is configured from an inverse model of the plant and a low-pass filter.

[0143] FIG. 9 is a schematic diagram showing the configuration of the torque control unit 59.

[0144] The torque control unit 59 (see FIG. 2) includes a motor current command value calculation unit 91 , a current deviation calculation unit 92 , a PI control unit 93 , and a PWM (Pulse Width Modulation) control unit 94 .

[0145] The motor current command value calculation unit 91 calculates the motor torque command value T ｍ，ｃｍｄ is the torque constant K of the electric motor 18. ｔ By dividing by , the motor current command value I ｍ，ｃｍｄ Calculate the following.

[0146] The current deviation calculation unit 92 calculates the motor current command value I obtained by the motor current command value calculation unit 91. ｍ，ｃｍｄ and the motor current I detected by the current detection circuit 42. ｍ Deviation ΔI (=I ｍ，ｃｍｄ -I ｍ ) is calculated.

[0147] The PI control unit 93 performs a PI calculation (proportional integral calculation) on the current deviation ΔI calculated by the current deviation calculation unit 92, thereby calculating the motor current I flowing through the electric motor 18 as a motor current command value I ｍ，ｃｍｄ The PWM control unit 94 generates a drive command value for guiding the electric motor 18 to the above-described drive command value. The PWM control unit 94 generates a PWM control signal with a duty ratio corresponding to the drive command value and supplies the PWM control signal to the drive circuit 41. As a result, electric power corresponding to the drive command value is supplied to the electric motor 18.

[0148] Next, a description will be given of the warning torque calculation unit 52. Referring to Fig. 2, the warning torque calculation unit 52 includes a warning determination unit 52A and a warning torque calculation unit 52B.

[0149] The warning determination unit 52A uses the side obstacle detection information to determine whether or not a warning torque should be applied to prevent the vehicle from colliding with the side obstacle. ｏｂｓ ,Y ｏｂｓ , actual steering angle θ ｃ , shift position information P ｓｈｉｆｔ Whether or not a warning torque should be applied is determined based on the coordinates of the side obstacle position X ｏｂｓ ,Y ｏｂｓ is an example of "detection information of an obstacle on the side of the vehicle" in the present disclosure.

[0150] When the warning determination unit determines that a warning torque should be applied, the warning torque calculation unit 52B calculates the steering angle of the vehicle (actual steering angle θ ｃ ) based on the warning torque T ＳＯＷ Calculate the warning torque T ＳＯＷ The calculation method will be described in detail later.

[0151] The warning torque calculation unit 52 performs side obstacle warning torque calculation processing in the cooperative steering mode. Note that the warning torque calculation unit 52 may also perform side obstacle warning torque calculation processing in the manual steering mode.

[0152] 10 is a flowchart showing the procedure of the side obstacle warning torque calculation process executed by the warning torque calculation unit 52. The process of FIG. 10 is repeatedly executed at predetermined calculation intervals.

[0153] The warning torque calculation unit 52 sets a main locus prediction line for collision determination (step S1). In this embodiment, the warning torque calculation unit 52 calculates a main locus prediction line based on the actual steering angle θ ｃ , shift position information P ｓｈｉｆｔ and vehicle speed V, the trajectory of the vehicle is predicted, and a main trajectory prediction line for collision detection is set.

[0154] Specifically, when the vehicle is moving forward, the warning torque calculation unit 52 calculates the actual steering angle θ as shown in FIG. 11A, for example. ｃ , shift position information P ｓｈｉｆｔ and vehicle speed V, the predicted position coordinates of the reference position Q of the vehicle 120 are calculated at regular intervals, thereby generating a trajectory prediction line 130 of the reference position Q of the vehicle 120. Then, the warning torque calculation unit 52 sets the obtained trajectory prediction line 130 as the main trajectory prediction line 130.

[0155] When the vehicle is moving backward, the warning torque calculation unit 52 calculates the actual steering angle θ as shown in FIG. 11B, for example. ｃ , shift position information P ｓｈｉｆｔ and vehicle speed V, the predicted position coordinates of the reference position Q of the vehicle 120 are calculated at regular intervals, thereby generating a trajectory prediction line 140 of the reference position Q of the vehicle 120. Then, the warning torque calculation unit 52 sets the obtained trajectory prediction line 140 as the main trajectory prediction line 140.

[0156] Next, the warning torque calculation unit 52 calculates the main trajectory prediction line 130 (140) and the side obstacle position coordinates X ｏｂｓ ,Y ｏｂｓ Based on the above, it is determined whether or not a first condition that there is a high possibility of collision with a side obstacle is met (step S2).

[0157] Specifically, the warning torque calculation unit 52 first sets a collision determination area E based on the main trajectory prediction line 130 (140). Then, the warning torque calculation unit 52 determines whether at least a part of a lateral obstacle is present within the collision determination area E, thereby determining whether a first condition, that a collision with a lateral obstacle is highly likely, is satisfied.

[0158] As described above, in this embodiment, the side obstacle position coordinate X ｏｂｓ ,Y ｏｂｓ is the coordinates of a plurality of points on the contour of a lateral obstacle in a plan view (coordinates on the contour) x ｏｂｓ ,y ｏｂｓ Multiple coordinates x on the contour ｏｂｓ ,y ｏｂｓ may be coordinates of a plurality of points on the contour of the side obstacle, spaced apart by a predetermined distance. The predetermined distance is preferably set to a value of 5 cm or less. The warning torque calculation unit 52 calculates the coordinates x on the contour by calculating the coordinates x ｏｂｓ ,y ｏｂｓ If at least one of the coordinates x on the contour is included in the collision determination area E, it is determined that at least a part of the side obstacle is present in the collision determination area E. ｏｂｓ ,y ｏｂｓ If none of the above is included within the collision determination area E, it is determined that no side obstacle exists within the collision determination area E. The same applies hereinafter.

[0159] 12A, for example, the warning torque calculation unit 52 generates trajectory prediction lines for the left and right rear wheel positions RL and RR of the vehicle body (hereinafter referred to as "auxiliary trajectory prediction lines 131, 132") based on the main trajectory prediction line 130. The auxiliary trajectory prediction lines 131, 132 include a left auxiliary trajectory prediction line 131 that is a trajectory prediction line for the left rear wheel position RL, and a right auxiliary trajectory prediction line 132 that is a trajectory prediction line for the right rear wheel position RR.

[0160] Specifically, the warning torque calculation unit 52 determines the predicted vehicle position and vehicle attitude for each predetermined time based on, for example, the main trajectory prediction line 130. Then, the warning torque calculation unit 52 generates a left auxiliary trajectory prediction line 131 by connecting the left rear wheel positions RL for each predetermined time. The warning torque calculation unit 52 also generates a right auxiliary trajectory prediction line 132 by connecting the right rear wheel positions RR for each predetermined time.

[0161] Next, the warning torque calculation unit 52 sets the area sandwiched between the two auxiliary trajectory prediction lines 131, 132 (area 133 indicated by dotted hatching in FIG. 12A ) as a collision determination area E. Then, the warning torque calculation unit 52 determines whether or not at least a part of a lateral obstacle is present within the collision determination area E. In FIG. 12A , reference numeral 121 denotes a lateral obstacle.

[0162] Note that instead of generating trajectory prediction lines for the left and right rear wheel positions RL, RR of the vehicle body as the auxiliary trajectory prediction lines 131, 132, the warning torque calculation unit 52 may generate trajectory prediction lines (not shown) for the left and right corners RCL, RCR (see FIG. 12A) at the rear of the vehicle body as the auxiliary trajectory prediction lines 131, 132. In this case, the auxiliary trajectory prediction lines 131, 132 include a left auxiliary trajectory prediction line 131 that is a trajectory prediction line for the left corner RCL at the rear of the vehicle body, and a right auxiliary trajectory prediction line 132 that is a trajectory prediction line for the right corner RCR at the rear of the vehicle body.

[0163] The warning torque calculation unit 52 determines that the first condition is met if at least a portion of a lateral obstacle is present within the collision determination area E, and determines that the first condition is not met if no lateral obstacle is present within the collision determination area E.

[0164] When the vehicle 120 is moving forward and the steering direction is a left steering direction, the warning torque calculation unit 52 may set the collision determination region E as follows. That is, the warning torque calculation unit 52 generates a left auxiliary trajectory prediction line 131 (see FIG. 12A ), which is a trajectory prediction line 131 of the left rear wheel position RL on the vehicle body, based on the main trajectory prediction line 130. Then, the warning torque calculation unit 52 sets the region sandwiched between the main trajectory prediction line 130 and the left auxiliary trajectory prediction line 131 as the collision determination region E.

[0165] When the vehicle 120 is moving forward and the steering direction is a right steering direction, the warning torque calculation unit 52 may set the collision determination region E as follows. That is, the warning torque calculation unit 52 generates a right auxiliary trajectory prediction line 132 (see FIG. 12A ), which is a trajectory prediction line 132 of the right rear wheel position RR on the vehicle body, based on the main trajectory prediction line 130. Then, the warning torque calculation unit 52 sets the region sandwiched between the main trajectory prediction line 130 and the right auxiliary trajectory prediction line 132 as the collision determination region E.

[0166] 12B , for example, the warning torque calculation unit 52 generates trajectory prediction lines for the left and right corners FCL, FCR in the front of the vehicle body (hereinafter referred to as "auxiliary trajectory prediction lines 141, 142") based on the main trajectory prediction line 140. The auxiliary trajectory prediction lines 141, 142 include a left auxiliary trajectory prediction line 141 that is a trajectory prediction line for the front left corner FCL of the vehicle body, and a right auxiliary trajectory prediction line 142 that is a trajectory prediction line for the front right corner FCR of the vehicle body.

[0167] Specifically, the warning torque calculation unit 52 determines the predicted vehicle position and vehicle attitude for each predetermined time period based on, for example, the main trajectory prediction line 140. Then, the warning torque calculation unit 52 generates a left auxiliary trajectory prediction line 141 by connecting the positions of the front left corner FCL of the vehicle body for each predetermined time period. The warning torque calculation unit 52 also generates a right auxiliary trajectory prediction line 142 by connecting the positions of the front right corner FCR of the vehicle body for each predetermined time period.

[0168] Next, the warning torque calculation unit 52 sets the area sandwiched between the two auxiliary trajectory prediction lines 141, 142 (area 143 indicated by dotted hatching in FIG. 12B ) as a collision determination area E. Then, the warning torque calculation unit 52 determines whether or not at least a part of the coordinates of a side obstacle is present within the collision determination area E. In FIG. 12B , reference numeral 121 denotes a side obstacle.

[0169] Note that instead of generating trajectory prediction lines for the left and right corners FCL, FCR at the front of the vehicle body as the auxiliary trajectory prediction lines 141, 142, respectively, the warning torque calculation unit 52 may generate trajectory prediction lines (not shown) for the left and right front wheel positions FL, FR (see FIG. 12B ) at the vehicle body as the auxiliary trajectory prediction lines 141, 142. In this case, the auxiliary trajectory prediction lines 141, 142 include a left auxiliary trajectory prediction line 141 that is a trajectory prediction line for the left front wheel position FL and a right auxiliary trajectory prediction line 142 that is a trajectory prediction line for the right front wheel position FR.

[0170] The warning torque calculation unit 52 determines that the first condition is met if at least a portion of a lateral obstacle is present within the collision determination area E, and determines that the first condition is not met if no lateral obstacle is present within the collision determination area E.

[0171] When the vehicle 120 is moving backward and the steering direction is a left steering direction (a right steering direction when facing backward), the warning torque calculation unit 52 may set the collision determination region E as follows. That is, the warning torque calculation unit 52 generates a right auxiliary trajectory prediction line 142 (see FIG. 12B ), which is a trajectory prediction line for a right corner FCR in front of the vehicle body, based on the main trajectory prediction line 140. Then, the warning torque calculation unit 52 sets the region sandwiched between the main trajectory prediction line 140 and the right auxiliary trajectory prediction line 142 as the collision determination region E.

[0172] When the vehicle 120 is moving backward and the steering direction is a right steering direction (left steering direction when facing backward), the warning torque calculation unit 52 may set the collision determination region E as follows. That is, the warning torque calculation unit 52 generates a left auxiliary trajectory prediction line 141 (see FIG. 12B ), which is a trajectory prediction line for the left corner FCL in front of the vehicle body, based on the main trajectory prediction line 140. Then, the warning torque calculation unit 52 sets the region sandwiched between the main trajectory prediction line 140 and the left auxiliary trajectory prediction line 141 as the collision determination region E.

[0173] If it is determined in step S2 that the first condition is satisfied (step S2: YES), the warning torque calculation unit 52 proceeds to step S3.

[0174] In step S3, the warning torque calculation unit 52 determines whether the vehicle speed V is equal to or less than a predetermined first threshold value and whether the torsion bar torque T ｔｂ is equal to or greater than a predetermined second threshold value and the shift position is other than Parking. The first threshold value may be set to a predetermined value of 8 km / h or more and 12 km / h or less. The second threshold value may be set to a predetermined value of 0.3 Nm or more and 0.7 Nm or less. The reason why the second condition includes the vehicle speed condition and the torsion bar torque condition will be described later.

[0175] If the second condition is met (step S3: YES), the warning torque calculation unit 52 determines whether or not a warning torque application flag F is set (step S4). The warning torque application flag F is a flag that stores whether or not a state in which a warning torque should be applied is present, and is set (F=1) if a state in which a warning torque should be applied is present, and is reset (F=0) if a state in which a warning torque should not be applied is present. The initial value of the warning torque application flag F is 0.

[0176] If the warning torque application flag F is reset (F=0) (step S4: NO), the warning torque calculation unit 52 sets the warning torque application flag F (F=1) (step S5) and then proceeds to step S6.

[0177] In step S6, the warning torque calculation unit 52 calculates the actual steering angle θ when the warning torque application flag F is set. ｃ The actual steering angle θ just before the warning torque is applied ｓｔｐ，ＳＯＷ After that, the warning torque calculation unit 52 proceeds to step S7 and stores the warning torque T ＳＯＷ Calculate the following.

[0178] If it is determined in step S4 that the warning torque application flag F is set (F=1) (step S4: YES), the warning torque calculation unit 52 proceeds to step S7 without performing the processing of steps S5 and S6.

[0179] That is, only when the determination in step S3 is affirmative while the warning torque application flag F is reset, the warning torque application flag F is changed from the reset state to the set state, and the actual steering angle θ at that time is ｃ is the actual steering angle θ just before the warning torque is applied ｓｔｐ，ＳＯＷ In other words, the actual steering angle θ immediately before the warning torque application is started is stored as ｓｔｐ，ＳＯＷ will be updated.

[0180] On the other hand, if the determination in step S3 is affirmative while the warning torque application flag F is set, the warning torque application flag F remains set, but the actual steering angle θ immediately before the start of application of the warning torque is ｓｔｐ，ＳＯＷ is not updated.

[0181] In step S7, the warning torque calculation unit 52 calculates the warning torque T ＳＯＷ The warning torque T ＳＯＷ The initial value of is zero.

[0182]

[0183] In equation (11), k ＳＯＷ is the spring constant for calculating the warning torque (where k ＳＯＷ >0) and is set in advance.

[0184] FIG. 13 shows the relationship between θ ｓｔｐ，ＳＯＷ Actual steering angle θ when ｃ Warning torque T ＳＯＷ 1 is a graph showing the characteristics of

[0185] Actual steering angle θ ｃ is θ ｓｔｐ，ＳＯＷ If the steering direction is less than the warning torque T ＳＯＷ is set to zero. Actual steering angle θ ｃ is θ ｓｔｐ，ＳＯＷ If the steering direction is the direction in which the vehicle approaches the lateral obstacle, the warning torque T ＳＯＷ is the actual steering angle θ ｃ The larger the actual steering angle θ ｃ is θ ｓｔｐ，ＳＯＷIn the example of FIG. 13, the warning torque T ＳＯＷ increases linearly, but may also increase nonlinearly.

[0186] In addition, the actual steering angle θ ｃ Warning torque T ＳＯＷ The characteristic of θ is shown by the broken line in FIG. ｃ is a predetermined value A (where A>θ ｓｔｐ，ＳＯＷ ) or more, the warning torque T ＳＯＷ The characteristic may be such that θ is constant. ｃ = θ ｓｔｐ，ＳＯＷ Warning torque T in the vicinity ＳＯＷ When the torque rises from zero, the warning torque T ＳＯＷ may be increased more smoothly.

[0187] In addition, the actual steering angle θ ｃ is θ ｓｔｐ，ＳＯＷ If the torque is greater than or equal to the predetermined torque, the warning torque T ＳＯＷ may be calculated.

[0188]

[0189] In formula (12), c ＳＯＷ is the viscous damping coefficient for calculating the warning torque (where c ＳＯＷ >0) and is set in advance.

[0190] FIG. 14 shows the relationship between θ ｓｔｐ，ＳＯＷ Actual steering angle θ when <0 ｃ Warning torque T ＳＯＷ 1 is a graph showing the characteristics of

[0191] Actual steering angle θ ｃ is θ ｓｔｐ，ＳＯＷ If the steering direction is larger than the warning torque T ＳＯＷ is set to zero. Actual steering angle θ ｃ is θ ｓｔｐ，ＳＯＷ If the actual steering angle θ is less than θ , the steering direction is the direction in which the vehicle approaches the lateral obstacle. ｃ The smaller the actual steering angle θ, the smaller the ｃ is θ ｓｔｐ，ＳＯＷIn the example of FIG. 14, if the warning torque T ＳＯＷ is decreasing linearly, but may also decrease nonlinearly.

[0192] In addition, the actual steering angle θ ｃ Warning torque T ＳＯＷ The characteristic of θ is shown by the broken line in FIG. ｃ is equal to or less than a predetermined value −A, the warning torque T ＳＯＷ The characteristic may be such that θ is constant. ｃ = θ ｓｔｐ，ＳＯＷ Warning torque T in the vicinity ＳＯＷ When the torque falls from zero, the warning torque T ＳＯＷ may be decreased more smoothly.

[0193] In addition, the actual steering angle θ ｃ is θ ｓｔｐ，ＳＯＷ If the value is less than the above, the warning torque T ＳＯＷ may be calculated.

[0194] When the processing of step S7 is completed, the warning torque calculation unit 52 ends the processing of the current calculation cycle.

[0195] In step S2, if it is determined that the first condition is not satisfied (step S2: NO), the warning torque calculation unit 52 resets the warning torque application flag F (F=0) (step S8), and then calculates the warning torque T ＳＯＷ = 0 (step S9). Then, the warning torque calculation unit 52 ends the processing for the current calculation cycle.

[0196] In step S3, if it is determined that the second condition is not satisfied (step S3: NO), the warning torque calculation unit 52 resets the warning torque application flag F (F=0) (step S8), and then calculates the warning torque T ＳＯＷ = 0 (step S9). Then, the warning torque calculation unit 52 ends the processing for the current calculation cycle.

[0197] 10 are performed by the warning determination unit 52 A. Step S7 is performed by the warning torque calculation unit 52 B.

[0198] The reason why the vehicle speed condition and the torsion bar torque condition are included in the second condition is as follows. The condition that the vehicle speed V is equal to or less than the first threshold value is set as follows. ＳＯＷ It is assumed that applying the torsion bar torque T is particularly effective in avoiding collisions with side obstacles when entering or leaving the parking lot. This condition is set because the vehicle speed is basically low when entering or leaving the parking lot. ｔｂ The reason for setting the condition that the absolute value of the warning torque T is equal to or greater than the predetermined second threshold value is as follows. ＳＯＷ The condition is set because it is assumed that the safety function operates when the driver is steering.

[0199] The operation of this embodiment will be described below.

[0200] In this embodiment, the manual steering mode is defined as the assist torque command value T ａｓ The cooperative steering mode refers to a steering mode in which the electric motor 18 is controlled based only on the automatic steering command value θ ａｄ and manual steering command value θ ｍｄ The integrated angle command value θ ｃｍｄ This refers to a steering mode in which the electric motor 18 is controlled based on the steering angle.

[0201] When the steering mode is set to the manual steering mode, the first switch 56 is turned on and the second switch 57 is turned off. When the steering mode is set to the cooperative steering mode, the first switch 56 is turned off and the second switch 57 is turned on. In other words, the motor control ECU 202 can switch the steering mode between the manual steering mode and the cooperative steering mode by the driver operating the mode switches 31 and 32.

[0202] Although the steering mode is switched by mode switches 31 and 32, host ECU 201 may switch the steering mode in response to an ON / OFF signal for the driving assistance function or the automatic driving function, obstacles, the driver's state, driver operations such as accelerator and brake, and the running state of the vehicle. In this case, host ECU 201 generates a mode setting signal in response to an ON / OFF signal for the driving assistance function or the automatic driving function, obstacles, the driver's state, driver operations such as accelerator and brake, and the running state of the vehicle, and provides the signal to motor control ECU 202.

[0203] In the above embodiment, the integrated angle command value θ ｃｍｄ and a cooperative steering mode in which the electric motor 18 can be controlled based on the assist torque command value T ａｓ This allows switching between a manual steering mode in which the electric motor 18 can be controlled based only on the steering angle.

[0204] That is, the integrated angle command value θ ｃｍｄ In the electric power steering system 1, the electric motor 18 can be controlled based on the assist torque command value T ａｓ Therefore, the electric motor 18 can be controlled based only on the above.

[0205] In the above-described embodiment, in the manual steering mode, the assist torque command value T ａｓ Since the electric motor 18 is controlled based only on the road surface reaction torque, the driver can receive the actual road surface reaction torque.

[0206] In the above-described embodiment, when it is determined that the first condition is satisfied in step S2 of FIG. 10 and the second condition is satisfied in step S3 during the cooperative steering mode, the warning torque T ＳＯＷ In the cooperative steering mode, the manual steering command value calculation unit 53 adds "-T" to the right side of the equation of motion in the formula (2). ＳＯＷ Based on the equation of motion to which " has been added, the manual steering command value θ ｍｄ (See equation (3)). ＳＯＷThis acts as a steering reaction force that suppresses steering (driver operation) in a direction that would cause the side of the vehicle to collide with a side obstacle, thereby making it possible to suppress the side of the vehicle from colliding with a side obstacle.

[0207] In the manual mode, the first switch 56 is turned off, the second switch 57 is turned on, and the automatic steering command value θ ａｄ may be set to 0. In this case, the warning torque calculation unit 52 and the manual steering command value calculation unit 53 are operated even in the manual mode. In this case, the manual steering mode is set to 0 when the manual steering command value θ ｍｄ This is the steering mode in which the electric motor 18 is controlled based only on the steering angle.

[0208] [Explanation of First Modification of Side Obstacle Warning Torque Calculation Process] The warning torque calculation unit 52 may perform a side obstacle warning torque calculation process as shown in Fig. 15 instead of the side obstacle warning torque calculation process of Fig. 10. In Fig. 15, steps that perform the same processes as the steps of the parts in Fig. 10 are denoted by the same step numbers as in Fig. 10. The process of Fig. 15 is repeatedly executed at predetermined calculation intervals.

[0209] The warning torque calculation unit 52 first determines whether or not the second condition is satisfied (step S3). The second condition is the same as the second condition described above.

[0210] In step S3, if the second condition is not satisfied (step S3: NO), the warning torque calculation unit 52 proceeds to step S8. After performing the process of step S8, the warning torque calculation unit 52 performs the process of step S9. Then, the warning torque calculation unit 52 ends the process for the current calculation cycle.

[0211] If it is determined in step S3 that the second condition is satisfied (step S3: YES), the warning torque calculation unit 52 sets a predicted main trajectory line (step S1) and then proceeds to step S2. If it is determined in step S2 that the first condition is satisfied (step S2: YES), the warning torque calculation unit 52 proceeds to step S4.

[0212] If the warning torque application flag F is reset (F=0) in step S4 (step S4: NO), the warning torque calculation unit 52 performs the processes of steps S5 and S6, and then proceeds to step S7.

[0213] If it is determined in step S4 that the warning torque application flag F is set (F=1) (step S4: YES), the warning torque calculation unit 52 proceeds to step S7 without performing the processing of steps S5 and S6.

[0214] In step S7, the warning torque calculation unit 52 calculates the warning torque T ＳＯＷ Then, the warning torque calculation unit 52 ends the processing for the current calculation cycle.

[0215] If it is determined in step S2 that the first condition is not satisfied (step S2: NO), the warning torque calculation unit 52 proceeds to step S8.

[0216] [Description of Modified Example of Main Locus Prediction Line] In the above embodiment, the warning torque calculation unit 52 calculates the actual steering angle θ ｃ , shift position information P ｓｈｉｆｔ and vehicle speed V, a trajectory prediction line of the reference position Q of the vehicle 120 is generated, and the obtained trajectory prediction line is set as the main trajectory prediction line 130 (see FIG. 11A), 140 (see FIG. 11B).

[0217] However, the warning torque calculation unit 52 calculates the actual steering angle θ ｃ The main trajectory prediction line may be set by predicting the trajectory of the vehicle using a steering angle having an absolute value greater than the actual steering angle θ. ｃ a first virtual steering angle G1·θ, which is a value obtained by multiplying the first virtual steering angle G1 by a first gain G1 greater than 1. ｃ may be regarded as the actual steering angle, a trajectory prediction line of the reference position Q of the vehicle 120 may be generated, and the obtained trajectory prediction line may be set as the main trajectory prediction line. ｃ The actual steering angle θ ｃHereinafter, the main locus prediction line set using the steering angle whose absolute value is larger than the actual steering angle θ may be referred to as a "first main locus prediction line." ｃ The main trajectory prediction line set using the above formula may be referred to as the "basic main trajectory prediction line."

[0218] An example of the first main trajectory prediction line when the basic main trajectory prediction line is the curve 130 in Figure 11A is shown by the dashed-dotted line 150 in Figure 11A. An example of the first main trajectory prediction line when the basic main trajectory prediction line is the curve 140 in Figure 11B is shown by the dashed-dotted line 160 in Figure 11B.

[0219] The collision detection region E is set in the same manner as described in the above embodiment. However, a first main trajectory prediction line is used instead of the basic main trajectory prediction line used in the above embodiment. When the collision detection region E is set based on the first main trajectory prediction line, collisions with lateral obstacles can be more reliably suppressed than when the collision detection region E is set based on the basic main trajectory prediction line.

[0220] On the other hand, when the collision determination region E is set based on the first main trajectory prediction line, there is a risk that the state where the first condition is satisfied and the state where the first condition is not satisfied may be repeatedly switched within a short period of time. ＳＯＷ The state in which the warning torque T ＳＯＷ There is a risk that the state may repeatedly switch between being granted and not being granted in a short period of time.

[0221] This point will be explained using Figure 16. In the explanation of Figure 16, it is assumed that the second condition is satisfied. Figure 16 shows state changes when the vehicle 120 moves forward while turning left. In Figure 16, the dashed line 131 indicates the left auxiliary trajectory prediction line generated based on the basic main trajectory prediction line, and the solid line 151 indicates the left auxiliary trajectory prediction line generated based on the first main trajectory prediction line.

[0222] The collision detection area E set based on the basic main trajectory prediction line is, for example, the area sandwiched between the left auxiliary trajectory prediction line 131 and the corresponding right auxiliary trajectory prediction line (or basic main trajectory prediction line) (not shown). The collision detection area E set based on the first main trajectory prediction line is, for example, the area sandwiched between the left auxiliary trajectory prediction line 151 and the corresponding right auxiliary trajectory prediction line (or first main trajectory prediction line) (not shown).

[0223] At time t1, the side obstacle 121 does not exist within the collision determination area E set based on the first main trajectory prediction line, so the first condition is not satisfied. ＳＯＷ is not granted.

[0224] At time t2, the side obstacle 121 is not present in the collision determination area E set based on the basic main trajectory prediction line, but at least a part of the side obstacle 121 is present in the collision determination area E set based on the first main trajectory prediction line, so the first condition is satisfied. ＳＯＷ will be granted.

[0225] When the vehicle advances a little after time t2 (time t3), the side obstacle 121 is no longer present in the collision determination area E set based on the first main trajectory prediction line, and the first condition is no longer satisfied. ＳＯＷ will no longer be granted.

[0226] When the collision determination area E is set based on the first main locus predicted line, such a state change is likely to be repeated. ＳＯＷ The state in which the warning torque T ＳＯＷ There is a risk that the state may repeatedly switch between being granted and not being granted in a short period of time.

[0227] The warning torque calculation unit 52 may set the first main locus prediction line as follows: ｃ The offset sign (θ ｃ ) * α is added to the first virtual steering angle (θ ｃ +sign(θ ｃ ) * α). sign(θ ｃ) is θ ｃ If θ is >0, it becomes 1, and ｃ If θ = 0, it becomes 0, and θ ｃ If α is less than 0, it is set to −1. α is a predetermined value (real number) greater than 0. Then, the warning torque calculation unit 52 calculates the first virtual steering angle (θ ｃ +sign(θ ｃ ) * α) is regarded as the actual steering angle, a trajectory prediction line of the reference position Q of the vehicle 120 is generated, and the obtained trajectory prediction line is set as the first main trajectory prediction line.

[0228] [Description of Second Modification of Side Obstacle Warning Torque Calculation Processing] Warning torque T ＳＯＷ The state in which the warning torque T ＳＯＷ In order to prevent the state in which the warning torque is applied from repeatedly switching between a state in which the warning torque is applied and a state in which the warning torque is not applied within a short period of time, the warning torque calculation unit 52 may perform a side obstacle warning torque calculation process as shown in Fig. 17. The process in Fig. 17 is repeatedly executed at predetermined calculation intervals.

[0229] The warning torque calculation unit 52 first determines whether or not the second condition is satisfied (step S11). For example, the warning torque calculation unit 52 determines whether or not the vehicle speed V is equal to or less than a predetermined first threshold value and the torsion bar torque T ｔｂ is equal to or greater than a predetermined second threshold value and the shift position is other than Parking. The setting ranges of the first threshold value and the second threshold value are as described above.

[0230] If the second condition is not satisfied (step S11: NO), the warning torque calculation unit 52 resets the warning torque application flag F (F=0) (step S18). The initial value of the warning torque application flag F is 0. After this, the warning torque calculation unit 52 calculates the warning torque T ＳＯＷ = 0 (step S19). ＳＯＷ The initial value of is 0. Then, the warning torque calculation unit 52 ends the processing for the current calculation cycle.

[0231] If it is determined in step S11 that the second condition is satisfied (step S11: YES), the warning torque calculation unit 52 sets a first main locus prediction line and a second main locus prediction line (step S12).

[0232] Specifically, the warning torque calculation unit 52 calculates the actual steering angle θ ｃ a first virtual steering angle G1·θ, which is a value obtained by multiplying the first virtual steering angle G1 by a first gain G1 greater than 1. ｃ is regarded as the actual steering angle, a trajectory prediction line of the reference position Q of the vehicle is generated, and the obtained trajectory prediction line is set as the first main trajectory prediction line. ｃ is multiplied by a second gain G2 that is greater than the first gain G1, ｃ is regarded as the actual steering angle, a trajectory prediction line of the reference position Q of the vehicle is generated, and the obtained trajectory prediction line is set as the second main trajectory prediction line.

[0233] An example of the first main trajectory prediction line and the second main trajectory prediction line when the basic main trajectory prediction line is the curve 130 in Fig. 11A is shown by the dashed-dot line 150 and the dashed-two-dot line 170 in Fig. 11A. An example of the first main trajectory prediction line and the second main trajectory prediction line when the basic main trajectory prediction line is the curve 140 in Fig. 11B is shown by the dashed-dot line 160 and the dashed-two-dot line 180 in Fig. 11B.

[0234] Next, the warning torque calculation unit 52 determines whether or not the warning torque application flag F has been reset (F=0) (step S13). The initial value of the warning torque application flag F is 0.

[0235] If the warning torque application flag F is reset (F=0) (step S13: YES), the warning torque calculation unit 52 calculates the first main trajectory prediction line 150 (160) and the side obstacle position coordinate X ｏｂｓ ,Y ｏｂｓ Based on the above, it is determined whether or not a third condition that there is a high possibility of collision with a side obstacle is met (step S14).

[0236] Specifically, the warning torque calculation unit 52 sets a collision determination area E (hereinafter referred to as the "first collision determination area E1") based on the first main trajectory prediction line 150 (160). The first collision determination area E1 is set in the same manner as described in the above embodiment. However, the first main trajectory prediction line 150 (160) is used instead of the basic main trajectory prediction line in the above embodiment.

[0237] The warning torque calculation unit 52 then determines whether or not at least a part of a side obstacle is present within the first collision determination area E1. If at least a part of a side obstacle is present within the first collision determination area E1, the warning torque calculation unit 52 determines that the third condition is satisfied, and if no side obstacle is present within the first collision determination area E1, the warning torque calculation unit 52 determines that the third condition is not satisfied.

[0238] That is, in this modified example, the warning torque T ＳＯＷ When no virtual steering angle G1·θ is given (when F=0), ｃ is regarded as the actual steering angle, and based on the trajectory of the vehicle predicted (first prediction result), it is determined whether or not there is a high possibility that the vehicle will collide with a lateral obstacle.

[0239] If it is determined in step S14 that the third condition is satisfied (step S14: YES), the warning torque calculation unit 52 sets the warning torque application flag F (F = 1) (step S15) and then proceeds to step S16.

[0240] In step S16, the warning torque calculation unit 52 calculates the actual steering angle θ when the warning torque application flag F is set. ｃ The actual steering angle θ just before the warning torque is applied ｓｔｐ，ＳＯＷ After that, the warning torque calculation unit 52 proceeds to step S17 and stores the warning torque T ＳＯＷ Calculate the warning torque T ＳＯＷ The initial value of is 0. The process of step S17 is the same as the process of step S7 in Fig. 10, and therefore a description thereof will be omitted. Then, the warning torque calculation unit 52 ends the process of the current calculation cycle.

[0241] If it is determined in step S14 that the third condition is not satisfied (step S14: NO), the warning torque calculation unit 52 proceeds to step S18.

[0242] In step S13, when it is determined that the warning torque application flag F is set (F=1) (step S13: NO), the warning torque calculation unit 52 calculates the second main trajectory prediction line 170 (180) and the side obstacle position coordinate X ｏｂｓ ,Y ｏｂｓ Based on the above, it is determined whether or not a fourth condition that there is a high possibility of collision with a side obstacle is met (step S20).

[0243] Specifically, the warning torque calculation unit 52 sets a collision determination area E (hereinafter referred to as the "second collision determination area E2") based on the second main trajectory prediction line 170 (180). The second collision determination area E2 is set in the same manner as described in the above embodiment. However, the second main trajectory prediction line 170 (180) is used instead of the basic main trajectory prediction line in the above embodiment.

[0244] The warning torque calculation unit 52 then determines whether or not at least a part of a side obstacle is present within the second collision determination area E2. If at least a part of a side obstacle is present within the second collision determination area E2, the warning torque calculation unit 52 determines that the fourth condition is satisfied, and if no side obstacle is present within the second collision determination area E2, the warning torque calculation unit 52 determines that the fourth condition is not satisfied.

[0245] That is, in this modified example, the warning torque T ＳＯＷ When F is given (when F=1), the second virtual steering angle G2·θ ｃ is regarded as the actual steering angle, and based on the trajectory of the vehicle predicted (second prediction result), it is determined whether or not there is a high possibility that the vehicle will collide with a lateral obstacle.

[0246] In step S20, when it is determined that the fourth condition is satisfied (step S20: YES), the warning torque calculation unit 52 proceeds to step S17, and calculates the warning torque T ＳＯＷ Then, the warning torque calculation unit 52 ends the processing for the current calculation cycle.

[0247] If it is determined in step S20 that the fourth condition is not satisfied (step S20: NO), the warning torque calculation unit 52 proceeds to step S18.

[0248] In the second modification of the side obstacle warning torque calculation process, the warning torque T ＳＯＷ When the second and third conditions are satisfied in the case where the warning torque is not applied (F=0), the warning torque application flag F is set (F=1) and the warning torque T ＳＯＷ The application of the warning torque T ＳＯＷ When the second condition is not satisfied or the fourth condition is not satisfied in the state where the flag F is set (F=1), the flag F is reset (F=0) and the warning torque T ＳＯＷ will no longer be granted.

[0249] That is, the warning torque T ＳＯＷ When the second and third conditions are not applied (F=0), the warning torque T ＳＯＷ This is the condition for starting the application of the warning torque T ＳＯＷ When the second condition is not satisfied (F=1), or when the warning torque T ＳＯＷ When the warning torque T ＳＯＷ This is a condition for granting or canceling the bonus.

[0250] The operation of the second modified example of the side obstacle warning torque calculation process will be described with reference to Fig. 18 . In the description of Fig. 18 , it is assumed that the second condition is satisfied. Fig. 18 shows state changes when the vehicle 120 moves forward while turning left. In Fig. 18 , the dashed line 131 indicates the left auxiliary trajectory prediction line generated based on the basic main trajectory prediction line, the solid line 151 indicates the left auxiliary trajectory prediction line generated based on the first main trajectory prediction line, and the solid line 171 indicates the left auxiliary trajectory prediction line generated based on the second main trajectory prediction line.

[0251] The first collision determination area E1 set based on the first main trajectory prediction line is, for example, the area between the left auxiliary trajectory prediction line 151 and the corresponding right auxiliary trajectory prediction line (or first main trajectory prediction line), not shown. The second collision determination area E2 set based on the second main trajectory prediction line is, for example, the area between the left auxiliary trajectory prediction line 171 and the corresponding right auxiliary trajectory prediction line (or second main trajectory prediction line), not shown.

[0252] At time t1, the warning torque application flag F is reset (F=0). At time t1, the side obstacle 121 does not exist within the first collision determination area E1, so the third condition is not satisfied. Therefore, the warning torque T ＳＯＷ is not granted.

[0253] At time t2, at least a part of the side obstacle 121 is present within the first collision determination area E1, so the third condition is satisfied. ＳＯＷ The warning torque application flag F is set (F=1).

[0254] At time t3, the side obstacle 121 is no longer present in the first collision determination area E1, but at least a part of the side obstacle 121 is present in the second collision determination area E2, so the fourth condition is satisfied. ＳＯＷ The state in which the value is assigned is maintained.

[0255] At time t4, the side obstacle 121 is no longer present within the second collision determination area E2, and therefore the fourth condition is no longer satisfied. ＳＯＷ The warning torque application flag F is reset (F=0).

[0256] In the second modification of the side obstacle warning torque calculation process, the warning torque T ＳＯＷ When the second and third conditions are satisfied in a state where the warning torque T ＳＯＷ On the other hand, the warning torque T ＳＯＷ When the second condition is satisfied in the state where the warning torque TＳＯＷ The warning torque T ＳＯＷ The state in which the warning torque T ＳＯＷ This makes it less likely that the state where the message is given and the state where it is not given will repeatedly switch within a short period of time.

[0257] In step S12, the warning torque calculation unit 52 may set the first main locus prediction line as follows: That is, the warning torque calculation unit 52 calculates the first main locus prediction line based on the actual steering angle θ ｃ The offset (sign(θ ｃ ) × α) is added to form a first virtual steering angle (θ ｃ +sign(θ ｃ )×α). The warning torque calculation unit 52 then calculates the first virtual steering angle (θ ｃ +sign(θ ｃ )×α) is regarded as the actual steering angle, a trajectory prediction line of the reference position Q of the vehicle 120 is generated, and the obtained trajectory prediction line is set as the first main trajectory prediction line.

[0258] The warning torque calculation unit 52 also calculates the first virtual steering angle (θ ｃ +sign(θ ｃ ) × α) with an offset (sign(θ ｃ ) × β) is added to form a second virtual steering angle (θ ｃ +sign(θ ｃ ) × α + sign(θ ｃ ) × β), where β is a predetermined value (real number) greater than 0. Then, the second virtual steering angle (θ ｃ +sign(θ ｃ ) × α + sign(θ ｃ ) × β) is regarded as the actual steering angle, a trajectory prediction line of the reference position Q of the vehicle 120 is generated, and the obtained trajectory prediction line is set as the second main trajectory prediction line.

[0259] That is, the warning torque calculation unit 52 calculates the actual steering angle θ ｃThe first main trajectory prediction line is set by regarding the first virtual steering angle, which is a steering angle with an absolute value larger than the first virtual steering angle, as the actual steering angle and predicting the trajectory of the reference position Q of the vehicle 120, and the second main trajectory prediction line is set by regarding the second virtual steering angle, which is a steering angle with an absolute value larger than the first virtual steering angle, as the actual steering angle and predicting the trajectory of the reference position Q of the vehicle 120.

[0260] [Description of a Modified Example of the Manual Steering Command Value Calculation Unit] Fig. 19 is a block diagram showing a modified example of the manual steering command value calculation unit. In Fig. 19, parts corresponding to those in Fig. 5 are denoted by the same reference numerals as in Fig. 5.

[0261] The manual steering command value calculation unit 53A in Fig. 19 differs from the manual steering command value calculation unit 53 in Fig. 5 in that a first limiter 111 and a second limiter 112 are added. The first limiter 111 is an example of a "first limiting processing unit" in the present disclosure, and the second limiter 112 is an example of a "second limiting processing unit" in the present disclosure.

[0262] The first limiter 111 is configured to limit the torsion bar torque T ｔｂ The second limiter 112 limits the absolute value of the assist torque command value T ａｓ The absolute value of is limited to a second upper limit value β (β>0) or less.

[0263] The first upper limit value α and the second upper limit value β are set, for example, by the warning torque calculation unit 52. When the warning torque application flag F is reset (F=0), the warning torque calculation unit 52 sets the first upper limit value α and the second upper limit value β to α1 and β1, respectively. When the warning torque application flag F is set (F=1), the warning torque calculation unit 52 sets the first upper limit value α and the second upper limit value β to α2, which is smaller than α1, and β2, which is smaller than β1, respectively. Furthermore, the first upper limit value α and the second upper limit value β are set based on the angular deviation (θ ｃ -θ ｓｔｐ，ＳＯＷ ) and over time.

[0264] As a result, when the first and second conditions are satisfied, the torsion bar torque T ｔｂ and the assist torque command value T ａｓ This reduces the absolute value of the torsion bar torque T ｔｂ and the assist torque command value T ａｓ Warning torque T for the absolute value of the sum of ＳＯＷ Since the ratio of the absolute value of the vehicle speed becomes larger, it becomes possible to more effectively suppress a collision of the vehicle side with a lateral obstacle.

[0265] [Description of Modified Motor Control ECU] Figure 20 is a block diagram showing a modified motor control ECU. In Figure 20, parts corresponding to those in Figure 2 are designated by the same reference numerals as in Figure 2.

[0266] Even when this modification is applied, the side obstacle position coordinate X ｏｂｓ ,Y ｏｂｓ , vehicle speed V and shift position information P ｓｈｉｆｔ is transmitted from the host ECU 201 to the motor control ECU 202A. In this modified example, for the sake of convenience, the host ECU 201 transmits the automatic steering command value θ ａｄ and steering mode signal S ｍｏｄｅ is not transmitted to the motor control ECU 202A.

[0267] The microcomputer 50 in the motor control ECU 202A includes, as a plurality of functional processing units, an assist torque command value setting unit 51, a warning torque calculation unit 52, a subtraction unit 58A, a torque control unit 59, a rotation angle calculation unit 69, and a reduction ratio division unit 70. The assist torque command value setting unit 51, the subtraction unit 58A, and the torque control unit 59 are examples of the "control unit" in the present disclosure. The subtraction unit 58A and the torque control unit 59 are examples of the "second control unit" in the present disclosure.

[0268] The assist torque command value setting unit 51 and the torque control unit 59 are similar to the assist torque command value setting unit 51 and the torque control unit 59 in Fig. 2, respectively, and therefore their description will be omitted. Also, the rotation angle calculation unit 69 and the reduction ratio division unit 70 are similar to the rotation angle calculation unit 69 and the reduction ratio division unit 70 in Fig. 6, and therefore their description will be omitted.

[0269] The warning torque calculation unit 52 constantly performs a side obstacle warning torque calculation process similar to the side obstacle warning torque calculation process described with reference to FIG. 10. The warning torque T ＳＯＷ is given to subtraction unit 58A.

[0270] The subtraction unit 58A subtracts the assist torque command value T ａｓ From the above, the warning torque T calculated by the warning torque calculation unit 52 is ＳＯＷ is subtracted, and the subtraction result is used as the motor torque command value T ｍ，ｃｍｄ Output as

[0271] In this modified example of the motor control ECU, for example, when the first condition in step S2 of FIG. 10 is satisfied and the second condition in step S3 is satisfied, the warning torque T ＳＯＷ Then, the subtraction unit 58A calculates the assist torque command value T ａｓ Warning torque T ＳＯＷ is subtracted, and the subtraction result is used as the motor torque command value T ｍ，ｃｍｄ This outputs the warning torque T ＳＯＷ This acts as a steering reaction force that suppresses steering (driver operation) in a direction that would cause the side of the vehicle to collide with a side obstacle, thereby making it possible to suppress the side of the vehicle from colliding with a side obstacle.

[0272] In this modified example of the motor control ECU, the warning torque calculation unit 52 may also perform side obstacle warning torque calculation processing similar to the side obstacle warning torque calculation processing described using FIG. 11 or FIG.

[0273] Although the embodiments and modifications of the present disclosure have been described above, the present disclosure can also be embodied in other forms.

[0274] In the embodiment and the modified example of the present disclosure, the second condition is that the vehicle speed V is equal to or less than a predetermined first threshold value, and the torsion bar torque T ｔｂ The second condition is that the absolute value of the torsion bar torque T is equal to or greater than a predetermined second threshold value, and the shift position is other than Parking. ｔｂ The second condition may be that the absolute value of the torsion bar torque T is equal to or greater than a predetermined second threshold and equal to or less than a predetermined third threshold, and the shift position is other than Parking. The third threshold may be set to a predetermined value of, for example, 4.5 Nm to 5.5 Nm. The second condition may be that the vehicle speed V is equal to or less than a predetermined first threshold, or that the torsion bar torque T is equal to or greater than a predetermined first threshold. ｔｂ The condition may be that the absolute value of the torsion bar torque T ｔｂ The condition may be that the absolute value of is equal to or greater than a predetermined second threshold and equal to or less than a predetermined third threshold.

[0275] In the above-described embodiment and the modified example of the motor control ECU, the vehicle may be equipped with a front obstacle sensor for detecting a front obstacle in front of the vehicle and a rear obstacle sensor for detecting a rear obstacle in the rear of the vehicle. When the front obstacle sensor detects a front obstacle, a first warning process may be performed to prevent the vehicle from colliding with the front obstacle. Similarly, when the rear obstacle sensor detects a rear obstacle, a second warning process may be performed to prevent the vehicle from colliding with the rear obstacle.

[0276] The first warning process may be to warn the driver by an image or sound (audio) that the vehicle is approaching an obstacle ahead, and the second warning process may be to warn the driver by an image or sound (audio) that the vehicle is approaching an obstacle behind.

[0277] The first warning process or the second warning process is performed when the warning torque T ＳＯＷ If the warning torque T ＳＯＷ may be configured not to be applied as a steering reaction force.

[0278] In the above-described embodiment, the angle control unit 55 (see FIG. 6) includes the feedforward control unit 63, but the feedforward control unit 63 may be omitted. In this case, the feedback control torque T ｆｂ is the basic target torque.

[0279] In addition, although the above-described embodiment shows an example in which the present disclosure is applied to motor control of a column-type EPS, the present disclosure can also be applied to motor control of EPS other than column-type EPS. Furthermore, the present disclosure can also be applied to control of an electric motor for steering angle control in a steer-by-wire system.

[0280] Although the embodiments of the present disclosure have been described in detail, these are merely examples used to clarify the technical content of the present disclosure, and the present disclosure should not be construed as being limited to these examples, and the scope of the present disclosure is limited only by the appended claims.

[0281] This application claims priority based on Patent Application No. 2023-205910 filed with the Japan Patent Office on December 6, 2023, the entire contents of which are incorporated herein by reference.

[0282] 1...electric power steering device, 3...steered wheels, 4...steering mechanism, 18...electric motor, 51...assist torque command value setting section, 52...side obstacle warning torque calculation section, 52A...warning determination section, 52B...warning torque calculation section, 53...manual steering command value calculation section, 54...integrated angle command value calculation section, 55...angle control section, 56...first switch, 57...second switch, 58...addition section, 58A...subtraction section, 59...torque control section, 201...host ECU, 202, 202A...motor control ECU

Claims

1. A motor control device for controlling the drive of an electric motor of a steering device, comprising: a warning determination unit that determines whether or not a warning torque should be applied to prevent the vehicle from colliding with an obstacle based on detection information of the obstacle on the side of the vehicle; a warning torque calculation unit that calculates the warning torque when the warning determination unit determines that a warning torque should be applied; and a control unit that controls the electric motor so that the warning torque calculated by the warning calculation unit acts as a steering reaction force.

2. A motor control device as described in claim 1, wherein the warning determination unit determines that the warning torque should be applied when a condition is met that the vehicle is highly likely to collide with the obstacle and the vehicle speed is equal to or less than a predetermined first threshold, or a condition is met that the vehicle is highly likely to collide with the obstacle and the torsion bar torque is equal to or greater than a predetermined second threshold.

3. A motor control device as described in claim 1, wherein the warning determination unit determines that the warning torque should be applied when the following conditions are met: there is a high possibility that the vehicle will collide with the obstacle, the vehicle speed is below a predetermined first threshold, and the torsion bar torque is greater than or equal to a predetermined second threshold.

4. A motor control device as described in claim 2 or 3, wherein the warning determination unit predicts the vehicle's trajectory based on the actual steering angle, information indicating whether the vehicle is moving forward or backward, and the vehicle speed, and determines whether there is a high possibility that the vehicle will collide with the obstacle based on the prediction result.

5. A motor control device as described in claim 2 or 3, wherein the warning determination unit predicts the vehicle's trajectory by regarding a virtual steering angle, which has an absolute value greater than that of the actual steering angle, information indicating whether the vehicle is moving forward or backward, and the vehicle speed, as if the virtual steering angle were an actual steering angle, and determines whether or not there is a high possibility that the vehicle will collide with the obstacle based on the prediction result.

6. The motor control device according to claim 2 or 3, wherein the warning determination unit obtains a first prediction result by predicting a trajectory of the vehicle based on a first virtual steering angle having an absolute value larger than the actual steering angle, information indicating whether the vehicle is moving forward or backward, and the vehicle speed, by regarding the first virtual steering angle as an actual steering angle, and obtains a second prediction result by predicting a trajectory of the vehicle based on a second virtual steering angle having an absolute value larger than the first virtual steering angle, the information indicating whether the vehicle is moving forward or backward, and the vehicle speed, by regarding the second virtual steering angle as an actual steering angle; when the warning torque is not applied, the motor control device determines whether or not the vehicle is likely to collide with the obstacle based on the first prediction result; and when the warning torque is applied, the motor control device determines whether or not the vehicle is likely to collide with the obstacle based on the second prediction result.

7. A motor control device as described in claim 1, wherein the control unit includes: a manual steering command value calculation unit that calculates a manual steering command value using a torsion bar torque; an integrated angle command value calculation unit that calculates an integrated angle command value by adding the manual steering command value to an automatic steering command value for driving assistance; and a first control unit for controlling the electric motor based on the integrated angle command value, wherein the manual steering command value is calculated by utilizing an equation of motion of a reference model of the steering device, and the warning torque is added to the equation of motion as a steering reaction force.

8. A motor control device as described in claim 7, further comprising a limiting processing unit that limits the absolute value of the torsion bar torque used in the calculation of the manual steering command value calculation unit to an upper limit value or less, and when the warning determination unit determines that the warning torque should be applied, the upper limit value is set to a value lower than the normal upper limit value.

9. The motor control device according to claim 8, wherein the manual steering command value calculation unit is configured to calculate a manual steering command value based on the torsion bar torque and an assist torque command value calculated using the torsion bar torque, and the motor control device further comprises a first limiting processing unit that limits the absolute value of the torsion bar torque used in the calculation of the manual steering command value calculation unit to a first upper limit value or less, and a second limiting processing unit that limits the absolute value of the assist torque command value used in the calculation of the manual steering command value calculation unit to a second upper limit value or less, and when the warning determination unit determines that the warning torque should be applied, the first upper limit value is set to a value lower than the first upper limit value under normal conditions, and the second upper limit value is set to a value lower than the second upper limit value under normal conditions.

10. A motor control device as described in claim 1, wherein the control unit includes: an assist torque command value calculation unit that calculates an assist torque command value using a torsion bar torque; a subtraction unit that subtracts the warning torque from the assist torque command value; and a second control unit that controls the electric motor based on a result of the subtraction by the subtraction unit.

11. A motor control device as described in claim 1, comprising: a first warning processing unit that performs a first warning processing based on detection information of a forward obstacle, which is an obstacle in front of the vehicle, to prevent the vehicle from colliding with the forward obstacle; and a second warning processing unit that performs a second warning processing based on detection information of a rear obstacle, which is an obstacle behind the vehicle, to prevent the vehicle from colliding with the rear obstacle, wherein if the first warning processing or the second warning processing is performed before it is determined that the warning torque should be applied, the warning torque is not applied as a steering reaction force.

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