Motor control device

Abstract

Provided is a motor control device comprising a dead zone processing unit which is provided to at least one of a steering torque input to a manual steering command value generation unit, an assist torque command value input to the manual steering command value generation unit, and a steering torque input to an assist torque command value calculation unit, and a dead zone width setting unit which changes a dead zone width of at least one dead zone processing unit of the dead zone processing units when, in a driving assistance mode, a result of determination, which is made by a hands-on / off determination unit and indicates that the state is a hands-off state, continues for a predetermined time or longer.

Description

[Technical Field]

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

[0002] Patent Document 1 discloses the following driving assistance technology. That is, a steering control unit calculates an X coordinate xc of a target passing point at the gaze-ahead distance and an X coordinate xe of an estimated passing point. The steering control unit then adds a calculation term obtained by multiplying the deviation (xc-xe) of these X coordinates xc, xe by a first control gain Gl to a calculation term obtained by multiplying the yaw angle θca by a second control gain Gy to calculate a motor control amount (torque command value) Tc. The first and second control gains Gl, Gy are set to larger values ​​the longer the hands-off time is, and when a hands-off state is not detected, the lower the level of wakefulness or the higher the level of absentmindedness is, the smaller the values ​​are set. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2011-57037 Summary of the Invention [Problem to be solved by the invention]

[0004] A prerequisite for driving assistance functions equivalent to Level 2 is that the driver must be holding the steering wheel. Therefore, in driving assistance mode, if the result of the determination that the driver has their hands off the steering wheel continues for a predetermined period of time or more, a warning is output, and if the hands-off state continues even after the warning, the driving assistance mode is canceled.

[0005] For this reason, in the driving assistance mode, it is necessary to accurately determine whether the vehicle is in a gripped state or a hands-off state. However, if the determination of whether the vehicle is in a gripped state or a hands-off state is based on the steering torque (torsion bar torque) detected by a torque sensor, in situations where the driver torque input is small, such as when driving in a straight line, there is a risk that the vehicle may be erroneously determined to be in a hands-off state even though the driver is gripping the vehicle.

[0006] An object of one embodiment of the present invention is to provide a motor control device that can accurately determine whether the hand is in a gripped state or a hands-free state in a driving assistance mode. [Means for solving the problem]

[0007] One embodiment of the present invention includes a torque detection unit for detecting steering torque, an assist torque command value setting unit for setting an assist torque command value using the steering torque, a manual steering command value generation unit for generating a manual steering command value using the steering torque and the assist torque command value, an integrated angle command value calculation unit for calculating an integrated angle command value by adding the manual steering command value to an automatic steering command value given in a driving assistance mode, a control unit for controlling the angle of an electric motor for steering angle control based on the integrated angle command value, and a steering wheel control unit for controlling the angle of an electric motor for steering angle control when the driver is in a gripping state where the driver is gripping the steering wheel or when the driver is in a gripping state where the driver is gripping the steering wheel. A motor control device is provided that includes a hands-on / off determination unit that determines whether the wheel is in a hands-off state and not being gripped; a plurality of dead-band processing units that are provided for at least one of the steering torque input to the manual steering command value generation unit, the assist torque command value input to the manual steering command value generation unit, and the steering torque input to the assist torque command value calculation unit; and a dead-band width setting unit that changes the dead-band width of at least one of the dead-band processing units when the hands-on / off determination unit determines that the wheel is in a hands-off state for a predetermined period of time or more during the driving assistance mode.

[0008] With this configuration, it becomes possible to accurately determine whether the device is in a gripped state or a hands-off state in the driving assistance mode.

[0009] One embodiment of the present invention is a motor control device including a torque detection unit for detecting steering torque, a steering angle detection unit for detecting an actual steering angle, an automatic steering control unit for setting an automatic steering control amount based on an automatic steering command value given in a driving assistance mode, an assist control unit for setting an assist control amount using the steering torque, an integrated control amount calculation unit for calculating an integrated control amount by adding the automatic steering control amount and the assist control amount, and a control unit for controlling an electric motor for steering angle control based on the integrated control amount, and further including a hands-on / off determination unit for determining whether the driver is in a gripped state where the driver is gripping the steering wheel or in a hands-off state where the driver is not gripping the steering wheel, and an actual manual steering angle calculation unit for calculating an actual manual steering angle which is a steering angle for manual steering based on the steering torque and the assist control amount. a steering angle calculation unit; and an actual automatic steering angle calculation unit that calculates an actual automatic steering angle, which is the steering angle for automatic steering based on the automatic steering control amount, by subtracting the actual manual steering angle from the actual steering angle, wherein the automatic steering control unit is configured to set the automatic steering control amount using the automatic steering command value and the actual automatic steering angle, and further includes a dead band processing unit provided for at least one of the steering torque to be input to the actual manual steering angle calculation unit, the assist control amount to be input to the actual manual steering angle calculation unit, and the steering torque to be input to the assist control unit, and a dead band width setting unit that changes the dead band width of at least one of the dead band processing units of the dead band processing unit when the hands-on / off determination unit determines that the vehicle is in a hands-off state for a predetermined period of time or more in the driving assistance mode.

[0010] With this configuration, it becomes possible to accurately determine whether the device is in a gripped state or a hands-off state in the driving assistance mode.

[0011] The above and other objects, features and advantages of the present invention will become apparent from the following description of the embodiments with reference to the accompanying drawings. [Brief explanation of the drawings]

[0012] [Figure 1] FIG. 1 is a schematic diagram showing the general configuration of an electric power steering system to which a motor control device according to one embodiment of the present invention is applied. [Figure 2] FIG. 2 is a block diagram illustrating the electrical configuration of the motor control ECU. [Figure 3] FIG. 3 is a graph showing an example of setting the assist torque command value T* m,ad relative to the steering torque Ttb. [Figure 4] FIG. 4 is a schematic diagram showing an example of a reference EPS model used in the manual steering command value setting unit. [Figure 5] FIG. 5 is a block diagram showing the configuration of the angle control unit. [Figure 6] FIG. 6 is a schematic diagram showing an example of the configuration of a physical model of an electric power steering system. [Figure 7] FIG. 7 is a block diagram showing the configuration of the disturbance torque estimating unit. [Figure 8] FIG. 8 is a schematic diagram showing the configuration of the torque control unit. [Figure 9] FIG. 9 is a flowchart showing the procedure of a first dead-band width setting process performed by a first dead-band width setting unit. [Figure 10] FIG. 10 is a graph showing an example of input / output characteristics of the first dead-zone width setting unit. [Figure 11] FIG. 11 is a time chart showing an example of changes in the first dead-band width W1 in the driving assistance mode. [Figure 12] FIG. 12 is a block diagram for explaining the electrical configuration of a first modified example of the motor control ECU. [Figure 13] FIG. 13 is a block diagram for explaining the electrical configuration of a second modified example of the motor control ECU. [Figure 14]FIG. 14 is a block diagram showing the configuration of the automatic steering control unit. [Figure 15] FIG. 15 is a schematic diagram showing an example of the configuration of a physical model of an electric power steering system. [Figure 16] FIG. 16 is a block diagram showing the configuration of the disturbance torque estimating section. [Figure 17] FIG. 17 is a block diagram for explaining the electrical configuration of a third modified example of the motor control ECU. DETAILED DESCRIPTION OF THE INVENTION

[0013] [Description of the embodiment of the present invention] One embodiment of the present invention includes a torque detection unit for detecting a steering torque, an assist torque command value setting unit for setting an assist torque command value using the steering torque, a manual steering command value generation unit for generating a manual steering command value using the steering torque and the assist torque command value, an integrated angle command value calculation unit for calculating an integrated angle command value by adding the manual steering command value to an automatic steering command value given in a driving assistance mode, a control unit for controlling the angle of an electric motor for steering angle control based on the integrated angle command value, and a control unit for controlling a steering angle control in a state where a driver is gripping the steering wheel or in a state where the driver is gripping the steering wheel. a dead-band processing unit provided for at least one of the steering torque input to the manual steering command value generation unit, the assist torque command value input to the manual steering command value generation unit, and the steering torque input to the assist torque command value calculation unit; and a dead-band width setting unit that changes the dead-band width of at least one of the dead-band processing units when the hands-on / off determination unit determines that the hands are in the hands-off state for a predetermined period of time or more during the driving assistance mode.

[0014] With this configuration, it becomes possible to accurately determine whether the device is in a gripped state or a hands-off state in the driving assistance mode.

[0015] One embodiment of the present invention is a motor control device including a torque detection unit for detecting steering torque, a steering angle detection unit for detecting an actual steering angle, an automatic steering control unit for setting an automatic steering control amount based on an automatic steering command value given in a driving assistance mode, an assist control unit for setting an assist control amount using the steering torque, an integrated control amount calculation unit for calculating an integrated control amount by adding the automatic steering control amount and the assist control amount, and a control unit for controlling an electric motor for steering angle control based on the integrated control amount, and further including a hands-on / off determination unit for determining whether the driver is in a gripped state where the driver is gripping the steering wheel or in a hands-off state where the driver is not gripping the steering wheel, and an actual manual steering angle calculation unit for calculating an actual manual steering angle which is a steering angle for manual steering based on the steering torque and the assist control amount. a steering angle calculation unit; and an actual automatic steering angle calculation unit that calculates an actual automatic steering angle, which is the steering angle for automatic steering based on the automatic steering control amount, by subtracting the actual manual steering angle from the actual steering angle, wherein the automatic steering control unit is configured to set the automatic steering control amount using the automatic steering command value and the actual automatic steering angle, and further includes a dead band processing unit provided for at least one of the steering torque to be input to the actual manual steering angle calculation unit, the assist control amount to be input to the actual manual steering angle calculation unit, and the steering torque to be input to the assist control unit, and a dead band width setting unit that changes the dead band width of at least one of the dead band processing units of the dead band processing unit when the hands-on / off determination unit determines that the vehicle is in a hands-off state for a predetermined period of time or more in the driving assistance mode.

[0016] With this configuration, it becomes possible to accurately determine whether the device is in a gripped state or a hands-off state in the driving assistance mode.

[0017] In one embodiment of the present invention, if the dead zone processing unit whose dead zone width is changed by the dead zone width setting unit is a dead zone processing unit with a variable dead zone width, the dead zone width setting unit is configured to increase the dead zone width of the variable dead zone processing unit when the hands-on / off determination unit determines that the vehicle is in a hands-off state for a predetermined period of time or more during the driving assistance mode.

[0018] In one embodiment of the present invention, when the hands-on / off determination unit determines that the vehicle is in a hands-off state for a predetermined period of time during the driving assistance mode, the dead zone width setting unit gradually increases the dead zone width from that point onwards as long as the determination that the vehicle is in a hands-off state continues, and when the dead zone width reaches a predetermined upper limit value, the dead zone width is maintained at the upper limit value.

[0019] In one embodiment of the present invention, when, in the driving assistance mode, the hands-on / off determination unit determines that the vehicle is in a hands-off state for a predetermined period of time or more, and then the determination result by the hands-on / off determination unit changes to a gripped state, the dead zone width setting unit gradually reduces the dead zone width from that point onwards as long as the determination result that the vehicle is in a gripped state continues, and when the dead zone width reaches a predetermined lower limit value, the dead zone width is maintained at the lower limit value.

[0020] Detailed Description of the Embodiments of the Invention Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

[0021] [1] Overview of electric power steering system FIG. 1 is a schematic diagram showing the general configuration of an electric power steering system to which a motor control device according to one embodiment of the present invention is applied.

[0022] 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.

[0023] 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.

[0024] A torque sensor (torque detection unit) 12 is disposed near the torsion bar 10. The torque sensor 12 detects the steering torque (torsion bar torque) T applied to the steering wheel 2 based on the amount of relative rotational displacement between the input shaft 8 and the output shaft 9. tb In this embodiment, the steering torque T tb For example, the torque for steering left is detected as a positive value, and the torque for steering right is detected as a negative value. The larger the absolute value of the torque, the greater the steering torque T tb The magnitude of is assumed to be large.

[0025] 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.

[0026] The rack shaft 14 extends linearly in the left-right direction of the vehicle. A rack 17 that meshes with the pinion 16 is formed in the middle of the rack shaft 14 in the axial direction. The pinion 16 and the rack 17 convert the rotation of the pinion shaft 13 into axial movement of the rack shaft 14. By moving the rack shaft 14 in the axial direction, the steered wheels 3 can be steered.

[0027] 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.

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

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

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

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

[0032] Steering 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 (driver torque) and the force generated by steering inertia.

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

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

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

[0036] In this embodiment, there are two driving modes: a normal mode and a driving assistance mode. In the driving assistance mode, the host ECU 201 controls the automatic steering command value θ * c,ad In this embodiment, the driving assistance is a lane centering assist (LCA) for maintaining the vehicle position in the center of the lane. * c,ad is the target value of the steering angle for driving the vehicle along the center of the lane. * c,ad is set based on, for example, the vehicle speed, the lateral deviation with respect to the target driving line, and the yaw deviation of the vehicle with respect to the target driving line. * c,ad Since the process of setting the automatic steering command value θ is well known, a detailed description thereof will be omitted here. * c,ad Set to zero.

[0037] The host ECU 201 also outputs a mode signal S indicating whether the driving mode is the normal mode or the driving assistance mode. mode The mode signal S mode , the automatic steering command value θ set by the host ECU 201 * c,ad and the vehicle speed V are provided to the motor control ECU 202 via the in-vehicle network. tb The output signal of the rotation angle sensor 23 is input to the motor control ECU 202. The motor control ECU 202 controls the electric motor 18 based on these input signals and information provided by the host ECU 201.

[0038] [2] Motor control ECU202 FIG. 2 is a block diagram for explaining the electrical configuration of motor control ECU 202. As shown in FIG.

[0039] The motor control ECU 202 includes a microcomputer 40, a drive circuit (inverter circuit) 31 controlled by the microcomputer 40 to supply power to the electric motor 18, and a current flowing through the electric motor 18 (hereinafter referred to as the "motor current I m,int The device is provided with a current detection circuit 32 for detecting the current.

[0040] The microcomputer 40 includes a CPU and memory (ROM, RAM, nonvolatile memory, etc.), and functions as a plurality of functional processing sections by executing predetermined programs. The plurality of functional processing sections include a rotation angle calculation section 41, a reduction ratio division section 42, a first dead-band processing section 43, an assist torque command value setting section 44, a second dead-band processing section 45, a manual steering command value generation section 46, an integrated angle command value calculation section 47, an angle control section 48, a torque control section 49, a hands-on / off determination section 50, a first dead-band width setting section 51, and a second dead-band width setting section 52.

[0041] The rotation angle calculation unit 41 calculates the rotor rotation angle θ of the electric motor 18 based on the output signal of the rotation angle sensor 23. m,intThe reduction ratio division unit 42 calculates the rotor rotation angle θ m,int By dividing by the reduction ratio N, the rotor rotation angle θ m,int The rotation angle (actual steering angle) of the output shaft 9 is θ c,int Convert to.

[0042] The first dead zone processing unit 43 receives the steering torque T tb The first dead zone processing unit 43 receives the steering torque T tb is within the range of -W1 / 2 or more and W1 / 2 or less (first dead band region), zero is set as the steering torque T tb,de (See FIG. 10, which will be described later.)

[0043] Steering torque T tb In the region where [T tb +(W1 / 2)] is the steering torque T after the first dead band processing. tb,de The steering torque T tb In the region where [T tb -(W1 / 2)] is the steering torque T after the first dead zone processing. tb,de The first dead zone width W1 is set by the first dead zone width setting unit 51.

[0044] The assist torque command value setting unit 44 sets the assist torque command value T * m,md The assist torque command value setting unit 44 sets the assist torque command value T tb Based on this, the assist torque command value T * m,md Set the steering torque T tb Assist torque command value T * m,md An example of the configuration is shown in Figure 3.

[0045] Assist torque command value T * m,mdis 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. * m,md is the steering torque T tb The steering torque T tb The assist torque command value T * m,md is the steering torque T tb The larger the absolute value of the assist torque command value T * m,md is set so that the absolute value thereof decreases as the vehicle speed V increases.

[0046] The assist torque command value setting unit 44 sets the steering torque T tb is multiplied by a preset constant to obtain the assist torque command value T * m,md may be calculated.

[0047] The second dead zone processing unit 45 receives the assist torque command value T * m,md The second dead zone processing unit 45 receives the assist torque command value T * m,md is within the range of -W2 / 2 or more and W2 / 2 or less (second dead band area), zero is set as the assist torque command value T * m,md,de Output as

[0048] Assist torque command value T * m,md In the region where [T * m,md +(W2 / 2)] is the assist torque command value T * m,md,de The assist torque command value T * m,mdIn the region where [T * m,md -(W2 / 2)] is the assist torque command value T after the second dead band processing. * m,md,de The second dead zone width W2 is set by the second dead zone width setting unit 52.

[0049] When the driver operates the steering wheel 2, the manual steering command value generating unit 46 generates a steering angle according to the steering wheel operation as a manual steering command value θ * c,md The manual steering command value generating unit 46 is provided to set the steering torque T after the first dead zone processing as tb,de and the assist torque command value T after the second dead band processing * m,md,de and the manual steering command value θ * c,md In this embodiment, the manual steering command value generating unit 46 generates the manual steering command value θ using the reference EPS model. * c.md Set.

[0050] FIG. 4 is a schematic diagram showing an example of a reference EPS model used in the manual steering command value generating unit 46.

[0051] This reference EPS model is a single-inertia model including a lower column. The lower column corresponds to the output shaft 9 and the worm wheel 21. In FIG. 4, J c is the inertia of the lower column, and θ c is the rotation angle of the lower column, and T tb,de is the steering torque after the first dead band processing. This reference EPS model uses the steering torque T tb,de and the assist torque command value T after the second dead band processing * m,md,de The torque N·T acting on the output shaft 9 from the electric motor 18 is * m,md,de and road load torque T rl The rotation angle θ of the lower column whenc This is a model for generating (estimating) the road load torque T rl is expressed by the following equation (1) using the spring constant k and the viscous damping coefficient c.

[0052] T rl =-k θ c -c(dθ c / dt) …(1) In this embodiment, predetermined values ​​obtained in advance through experiments, analyses, etc. are set as the spring constant k and the viscous damping coefficient c.

[0053] The equation of motion of the reference EPS model is expressed by the following equation (2).

[0054] J c ·d 2 θ c / dt 2 =T tb,de +N·T * m,md,de -k θ c -c(dθ c / dt) …(2) The manual steering command value generating unit 46 calculates the rotation angle θ of the lower column by solving the differential equation of the formula (2). c Then, the manual steering command value generating unit 46 calculates the obtained rotation angle θ of the lower column. c The manual steering command value θ * c,md Set as.

[0055] The integrated angle command value calculation unit 47 calculates the automatic steering command value θ set by the host ECU 201. * c,ad Manual steering command value θ * c,md The integrated angle command value θ * c,int Calculate the following.

[0056] The angle control unit 48 calculates the integrated angle command value θ * c,int Based on this, the motor torque command value T * m,intThe torque control unit 49 calculates the motor torque of the electric motor 18 in accordance with the motor torque command value T * m,int That is, the control unit consisting of the angle control unit 48 and the torque control unit 49 controls the actual steering angle θ c,int (rotation angle θ of output shaft 9 c,int ) is the integrated angle command value θ * c,int The drive circuit 31 is controlled so that the angle of the rotational axis 48 approaches the angle of the rotational axis 49. The operations of the angle control unit 48 and the torque control unit 49 will be described in detail later.

[0057] The hands-on / off determination unit 50 determines whether the driver is in a gripping state (hands-on) where the driver is gripping the steering wheel 2, or in a hands-off state (hands-off) where the driver is not gripping the steering wheel 2. The hands-on / off determination unit 50 determines, for example, the steering torque T tb and the actual steering angle θ c,int or rotor rotation angle θ m,int Based on the above, the driver torque, which is the torque applied to the steering wheel 2 by the driver, is estimated, and if the driver torque is equal to or greater than a predetermined threshold, the state is determined to be gripped, and if the state in which the driver torque is less than the threshold continues for a predetermined time or more, the state is determined to be hands-off. In this case, after the driver torque changes from a state equal to or greater than the threshold to a state less than the threshold, the state is determined to be gripped until the state is determined to be hands-off.

[0058] As such a hands-on / off determination unit 50, for example, a "steering wheel operation state determination unit" described in Patent Publication No. 2017-114324, Patent Publication No. 2018-165156, Patent Publication No. 2020-142703, Patent Publication No. 2020-59361, Patent Publication No. 2020-59362, etc. can be used.

[0059] The hands-on / off determination unit 50 determines, for example, the steering torque T tb is equal to or greater than a predetermined threshold, it is determined that the vehicle is in a gripping state, and the steering torque T tbThe steering torque T may be determined to be in a hands-off state when the steering torque T is less than the threshold value for a predetermined period of time. tb After the value of the threshold value changes from a value equal to or greater than the threshold value to a value less than the threshold value, the state is determined to be the grip state until the state is determined to be the no-hand state.

[0060] In the driving assistance mode, the first dead zone width setting unit 51 and the second dead zone width setting unit 52 respectively set the first dead zone width W1 and the second dead zone width W2 based on the hands-on / off determination result of the hands-on / off determination unit 50. The operations of the first dead zone width setting unit 51 and the second dead zone width setting unit 52 will be described in detail later.

[0061] FIG. 5 is a block diagram showing the configuration of the angle control unit 48.

[0062] The angle control unit 48 calculates the integrated angle command value θ * c,int Based on the motor torque command value T * m,int The angle control unit 48 includes a low-pass filter (LPF) 61, a feedback control unit 62, a feedforward control unit 63, a disturbance torque estimation unit 64, a torque addition unit 65, a disturbance torque compensation unit 66, a reduction ratio division unit 67, and a reduction ratio multiplication unit 68.

[0063] The reduction ratio multiplication unit 68 multiplies the motor torque command value T * m,int is multiplied by the reduction ratio N of the reducer 19 to obtain the motor torque command value T * m,int is the output shaft torque command value T * c,int (=N·T * m,int )

[0064] The low-pass filter 61 calculates the integrated angle command value θ * c,int The integrated angle command value θ after low-pass filtering is * c,intfis provided to the feedback control section 62 and the feedforward control section 63.

[0065] The feedback control unit 62 calculates the actual steering angle θ calculated by the reduction ratio division unit 42 (see FIG. 2). c,int is the integrated angle command value θ after low-pass filtering. * c,intf 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 * c,intf and the actual steering angle θ calculated by the reduction ratio division unit 42. c,int Deviation Δθ c,int (=θ * c,intf -θ c,int ) is calculated. The angle deviation calculation unit 62A calculates the integrated angle command value θ * c,intf and the steering angle estimated value ^θ calculated by the disturbance torque estimator 64. c,int deviation from (θ * c,intf -^θ c,int ) and the angle deviation Δθ c,int It may be calculated as follows.

[0066] The PD control unit 62B calculates the angle deviation Δθ calculated by the angle deviation calculation unit 62A. c,int By performing PD calculation (proportional differential calculation) on the feedback control torque T fb,int Calculate the feedback control torque T fb,int is given to the torque adder 65.

[0067] 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 * c,intf By taking the second derivative, the target angular acceleration d 2 θ *c,intf / dt 2 Calculate the following.

[0068] The inertia multiplication unit 63B multiplies the target angular acceleration d calculated by the angular acceleration calculation unit 63A by 2 θ * c,intf / dt 2 is multiplied by the inertia J of the electric power steering system 1 to obtain the feedforward control torque T ff,int (=J·d 2 θ * c,intf / dt 2 The inertia J can be calculated from, for example, a physical model (see FIG. 6) of the electric power steering system 1, which will be described later. The feedforward control torque T ff,int is given to the torque adder 65 as an inertia compensation value.

[0069] The torque adder 65 calculates the feedback control torque T fb,int to the feedforward control torque T ff,int By adding fb,int +T ff,int ) is calculated.

[0070] 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 an output shaft torque command value T * c,int (=N·T * m,int ) and the actual steering angle θ, which is the plant output c,int Based on this, the disturbance torque (disturbance load) T lc , steering angle θ c,int and steering angle differential value (angular velocity) dθ c,int / dt is estimated. lc , steering angle θ c,int and steering angle differential value (angular velocity) dθ c,int / dt estimates, respectively, lc , ^θ c,intand d^θ c,int The disturbance torque estimating section 64 will be described in detail later.

[0071] 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.

[0072] The disturbance torque compensator 66 calculates the basic torque command value (T fb,int +T ff,int ) to the estimated disturbance torque ^T lc By subtracting the output torque command value T * c,int (=T fb,int +T ff,int -^T lc ) is calculated. This results in the output shaft torque command value T * c,int (torque command value for output shaft 9) is obtained.

[0073] Output shaft torque command value T * c,int is given to the reduction ratio division unit 67. The reduction ratio division unit 67 calculates the output shaft torque command value T * c,int By dividing by the reduction ratio N, the motor torque command value T * m,int This motor torque command value T * m,int is given to the torque control section 49 (see FIG. 2).

[0074] The disturbance torque estimation unit 64 will be described in detail. The disturbance torque estimation unit 64 uses, for example, a physical model 101 of the electric power steering system 1 shown in FIG. 6 to estimate the disturbance torque T lc , steering angle θ c,int and angular velocity dθ c,int It consists of a disturbance observer that estimates / dt.

[0075] This physical model 101 includes a plant (an example of a motor-driven object) 102 including an output shaft 9 and a worm wheel 21 fixed to the output shaft 9. The plant 102 receives a steering torque T tb is applied, and a road load torque T rl is given.

[0076] Furthermore, the plant 102 receives an output shaft torque command value T * c,int (=N·T * m,int ) is given, and friction torque T f is given.

[0077] When the inertia of the plant 102 is J, the equation of motion for the inertia of the physical model 101 is expressed by the following equation (3).

[0078]

number

[0079] d 2 θ c,int / dt 2 is the angular acceleration of the plant 102. N is the reduction ratio of the reducer 19. T lc represents a disturbance torque other than the motor torque applied to the plant 102. In this embodiment, the disturbance torque T lc is the steering torque T tb and road load torque T rl and friction torque T f However, in reality, the disturbance torque T lc includes torques other than these.

[0080] The state equation for the physical model 101 in FIG. 6 is expressed by the following equation (4).

[0081]

number

[0082] In the above formula (4), x is a state variable vector, u1 is a known input vector, u2 is an unknown input vector, and y is an output vector (measurement value). In the above formula (4), A is a system matrix, B1 is a first input matrix, B2 is a second input matrix, C is an output matrix, and D is a direct feedthrough matrix.

[0083] The state equation is expanded to a system including the unknown input vector u2 as one of the states. The state equation of the expanded system (expanded state equation) is expressed by the following equation (5).

[0084]

number

[0085] In the formula (5), x e is the state variable vector of the extended system and is expressed by the following equation (6).

[0086]

number

[0087] In the formula (5), A e is the system matrix of the extended system, B e is the known input matrix of the extended system, C e is the output matrix of the augmented system.

[0088] From the extended state equation of the above formula (5), a disturbance observer (extended state observer) expressed by the following formula (7) is constructed.

[0089]

number

[0090] In equation (7), ^x e x erepresents 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 (8).

[0091]

number

[0092] In equation (8), ^θ c,int is θ c,int is an estimate of ^T lc is T lc is an estimate of

[0093] The disturbance torque estimation unit 64 calculates the state variable vector ^x based on the equation (7). e Calculate the following.

[0094] FIG. 7 is a block diagram showing the configuration of the disturbance torque estimating unit 64.

[0095] 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.

[0096] The output shaft torque command value T calculated by the reduction ratio multiplication unit 68 (see FIG. 5) * c,int (=N·T * m,int ) is given to the input vector input unit 81. The input vector input unit 81 outputs the input vector u1.

[0097] The output of the integrator 88 is the state variable vector ^x e (See equation (8) above.) At the start of calculation, the state variable vector ^x e The initial value is given as the state variable vector ^x e The initial value of is, for example, 0.

[0098] The system matrix multiplication unit 86 multiplies the state variable vector ^x e In the 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.

[0099] The first adder 83 calculates the actual steering angle θ calculated by the reduction ratio divider 42 (see FIG. 2). c,int From the output vector (measurement value) y, which is 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 ) and calculates the difference (y-^y). The gain multiplication unit 84 multiplies the output (y-^y) of the first addition unit 83 by the observer gain L (see equation (7) above).

[0100] The input matrix multiplication unit 85 multiplies the input vector u1 output from the input vector input unit 81 by the input matrix B e The second adder 87 multiplies the output (Be·u1) of the input matrix multiplier 85 by the output (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 (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,int and the estimated angular velocity d^θ c,int Calculates / dt.

[0101] Unlike the extended state observer described above, a general disturbance observer consists of an inverse model of the plant and a low-pass filter. The equation of motion of the plant is expressed by equation (3) as described above. Therefore, the inverse model of the plant is expressed by the following equation (9).

[0102]

number

[0103] The input to a typical disturbance observer is J d 2 θ c,int / dt 2 and N.T. * m,int and the actual steering angle θ c,int 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.

[0104] 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.

[0105] 8 is a block diagram showing the electrical configuration of torque control unit 49. Torque control unit 49 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.

[0106] The motor current command value calculation unit 91 calculates the motor torque command value T * m,int The torque constant K of the electric motor 18 t By dividing by, the motor current command value I * m,int Calculate the following.

[0107] The current deviation calculation unit 92 calculates the motor current command value I obtained by the motor current command value calculation unit 91. * m,intand the motor current I detected by the current detection circuit 32 m,int Deviation ΔI m,int (=I * m,int -I m,int ) is calculated.

[0108] The PI control unit 93 calculates the current deviation ΔI m,int By performing a PI calculation (proportional integral calculation) on m,int The motor current command value I * m,int The PWM control unit 94 generates a PWM control signal with a duty ratio corresponding to the drive command value and supplies it to the drive circuit 31. As a result, power corresponding to the drive command value is supplied to the electric motor 18.

[0109] Next, a detailed description will be given of the operations of the first dead-band width setting unit 51 and the second dead-band width setting unit 52. The first dead-band width setting unit 51 performs a first dead-band width setting process to set a first dead-band width W1 in the driving assistance mode. The second dead-band width setting unit 52 performs a second dead-band width setting process to set a second dead-band width W2 in the driving assistance mode.

[0110] Fig. 9 is a flowchart showing the procedure of the first dead-zone width setting process performed by the first dead-zone width setting unit 51. The first dead-zone width setting process shown in Fig. 9 is started every time the driving assistance mode is started, and is repeatedly performed at predetermined calculation intervals until the driving assistance mode is cancelled.

[0111] In the following, ΔT is the time (sampling time) corresponding to one calculation period. off is the duration of the release state. W 1_min is the minimum value of the first dead band width W1 set in advance (hereinafter referred to as the "first dead band width minimum value W 1_min The normal value of the first dead band width W1 is the minimum value of the first dead band width W 1,min It is set as W 1_maxis the maximum value of the first dead band width W1 set in advance (hereinafter referred to as "maximum first dead band width W 1_max "). W 1_decrease is the amount of decrease in the first dead band width in one preset calculation period. 1_increase is the preset increase in the first dead band width in one calculation cycle. The initial value of W1 is W 1_min T off The initial value of is 0.

[0112] The first dead-band width setting unit 51 determines whether the result of the determination by the hands-on / off determination unit 50 is a hands-off state (step S1).

[0113] If the determination result of the hands-on / off determination unit 50 is the gripping state (step S1: NO), the first dead zone width setting unit 51 sets the duration T off is set to zero (step S2). Then, the first dead-band width setting unit 51 sets the first dead-band width W1 to the first dead-band width minimum value W 1_min It is determined whether it is greater than (step S3).

[0114] The first dead band width W1 is the first dead band width minimum value W 1_min If the first dead band width W1 is larger than the first dead band width W2 (step S3: YES), the first dead band width setting unit 51 reduces the first dead band width W1 by the first dead band width reduction amount W 1_decrease The value obtained by subtracting W from the first dead band width W is set as the first dead band width W1 (step S4). 1_decrease The value obtained by subtracting this is the first dead band width minimum value W 1_min If the first dead zone width setting unit 51 determines that the first dead zone width minimum value W 1_min is set as the first dead-band width W1. Then, the first dead-band width setting unit 51 ends the processing for the current calculation cycle.

[0115] In step S3, the first dead zone width W1 is set to the first dead zone width minimum value W 1_min If it is determined that the value is equal to or less than the first dead zone width minimum value W (step S3: NO), the first dead zone width setting unit 51 sets the first dead zone width minimum value W 1_minis set as the first dead-band width W1 (step S5). Then, the first dead-band width setting unit 51 ends the processing in the current calculation cycle.

[0116] In step S1, when the hands-on / off determination unit 55 determines that the hand is not in the hands-off state (step S1: YES), the first dead-band width setting unit 51 sets the duration T off The value obtained by adding ΔT to off (Step S6). In other words, the duration of the hands-off state T off will be updated.

[0117] Next, the first dead zone width setting unit 51 determines the duration T off is a given time T _start (Step S7) off is a given time T _start If it is less than or equal to T off ≦T _start If so (step S7: NO), the first dead-band width setting unit 51 proceeds to step S3.

[0118] In step S7, the duration T off is a given time T _start If it is determined to be longer than T off >T _start If it is determined that the first dead zone width W1 is equal to or greater than the first dead zone width maximum value W 1_max (Step S8) It is determined whether the first dead zone width W1 is smaller than the first dead zone width maximum value W 1_max If it is smaller than (step S8: YES), the first dead-band width setting unit 51 adds the first dead-band width W1 to the first dead-band width increase amount W 1_increase The value obtained by adding the first dead band width W1 to the first dead band width W2 is set as the first dead band width W1 (step S9). 1_increase The value obtained by adding these is the maximum value of the first dead band width W 1_max If the first dead zone width setting unit 51 determines that the first dead zone width maximum value W 1_maxis set as the first dead-band width W1. Then, the first dead-band width setting unit 51 ends the processing for the current calculation cycle.

[0119] In step S8, the first dead zone width W1 is set to the first dead zone width maximum value W 1_max If it is determined that the value is equal to or greater than the first dead zone width (step S8: NO), the first dead zone width setting unit 51 sets the first dead zone width maximum value W 1_maxx is set as the first dead-band width W1 (step S10: NO), and the first dead-band width setting unit 51 ends the processing in the current calculation cycle.

[0120] FIG. 10 is a graph showing an example of input / output characteristics of the first dead band processing unit 43. In FIG.

[0121] The broken line L1 indicates that the first dead band width W1 is equal to the first dead band width minimum value W 1_min The broken line L2 shows the input / output characteristics of the first dead band processing unit 43 when the first dead band width W1 is set to the first dead band width maximum value W 1_max 10 shows the input / output characteristics of the first dead band processing unit 43 when the setting is

[0122] Normally, the first dead band width W1 is the minimum value W 1_min The duration of the hands-off state is set to T off is a given time T _start If the width of the first dead band W1 is longer than W 1_min <W1≦W 1_max The value will be in the range.

[0123] FIG. 11 is a time chart showing an example of changes in the first dead-band width W1 in the driving assistance mode.

[0124] In FIG. 11, at time t0, the first dead band width W1 is the normal value, the first dead band width minimum value W 1_minIn the example of Fig. 11, from time t0 to time t1, the judgment result of the hands-on / off judgment unit 50 is the gripping state (grip judgment). From time t1 to time t4, the judgment result of the hands-on / off judgment unit 50 is the no-hands state (no-hands judgment). From time t4 onwards, the judgment result of the hands-on / off judgment unit 50 is the gripping state (grip judgment).

[0125] During the period from time t0 to time t1, the result of the judgment by the hands-on / off judgment unit 50 is the grip state (grip judgment), so the first dead zone width W1 is the first dead zone width minimum value W 1_min Maintain.

[0126] Even if the determination result of the hands-on / off determination unit 50 changes to the hands-off state (hands-off determination) at time t1, _start Until time has elapsed, the first dead band width W1 is equal to the first dead band width minimum value W 1_min Maintain.

[0127] A predetermined time T from time t1 _start After the time t2 has elapsed, the first dead band width W1 increases. Then, the first dead band width W1 reaches the first dead band width maximum value W 1_max (time t3), the first dead band width W1 reaches the first dead band width maximum value W 1_max Maintain.

[0128] When the determination result of the hands-on / off determination unit 50 changes to the grip state (grip determination) at time t4, the first dead zone width W1 decreases. Then, the first dead zone width W1 decreases to the first dead zone width minimum value W 1_min (time t5), the first dead band width W1 reaches the first dead band width minimum value W 1_min Maintain.

[0129] 11, it is preferable to make the absolute value of the amount of change per unit time of the first dead-band width W1 when decreasing the first dead-band width W1 (the absolute value of the slope of the graph between t4 and t5 in FIG. 11) larger than the absolute value of the amount of change per unit time of the first dead-band width W1 when increasing the first dead-band width W1 (the absolute value of the slope of the graph between t2 and t3 in FIG. 11). 1_increase The first dead band width reduction amount W 1_decrease It is preferable to increase

[0130] The reason for this is as follows: The first dead band width W1 is increased when a hands-off determination is made. Since a hands-off determination is a more doubtful determination than a grip determination, it is preferable that the amount of change per unit time of the first dead band width W1 when the first dead band width is increased is relatively small. On the other hand, the first dead band width W1 is decreased when a grip determination is made. Since a grip determination is a more accurate determination than a hands-off determination, it is preferable that the first dead band width W1 is returned to the normal state as quickly as possible when the first dead band width is decreased. However, the first dead band width increase amount W 1_increase and the first dead band width reduction amount W 1_decrease may have the same value.

[0131] The second dead-band width setting process performed by the second dead-band width setting unit 52 is the same as the second dead-band width setting process of Fig. 9. However, in the second dead-band width setting process, the first dead-band width W1 and the first dead-band width minimum value W 1_min , maximum value of first dead band width W 1_max , first dead band width reduction amount W 1_decrease and the first dead band width increase amount W 1_increase are the second dead band width W2 and the second dead band width minimum value W 2_min , second dead band width maximum value W 2_max , second dead band width reduction amount W 2_decrease and the second dead band width increase amount W 2_increase can be replaced by

[0132] When the operation mode is the normal mode, the first dead zone width setting unit 51 sets the first dead zone width minimum value W 1_minis set as the first dead zone width W1, and the second dead zone width setting unit 52 sets the second dead zone width minimum value W 2_min is set as the second dead band width W2. In other words, in the normal mode, the first dead band width W1 and the second dead band width W2 are not changed.

[0133] In the above-described embodiment, in the driving assistance mode, when the hands-on / off determination unit 50 determines that the driver is in a hands-off state for a predetermined period of time or more, the first dead zone width W1 and the second dead zone width W2 are increased. When the first dead zone width W1 and the second dead zone width W2 are increased, the manual steering command value θ * c,md As a result, the amount of rotation of the output shaft 9 based on the driver torque becomes smaller, so that the torsion bar 10 is more likely to twist even with a relatively small rotation of the steering wheel 2 operated by the driver. tb and driver torque increases, which increases the accuracy of the hands-on / off determination by the hands-on / off determination unit 50. This makes it possible to prevent or suppress erroneous determination that the driver is in a hands-off state despite gripping the steering wheel 2 in situations where there is little driver torque input, such as when driving in a straight line.

[0134] [3] First Modification of Motor Control ECU 202 Fig. 12 is a block diagram for explaining the electrical configuration of a modified example of motor control ECU 202. In Fig. 12, parts corresponding to those in Fig. 2 described above are denoted by the same reference numerals as in Fig. 2.

[0135] In the first modified example, the configuration of the functional processing unit in the microcomputer 40A is different from that in Fig. 2. Specifically, in the first modified example, a third dead band processing unit 53 and a third dead band width setting unit 54 are provided instead of the first dead band processing unit 43, the second dead band processing unit 45, the first dead band width setting unit 51, and the second dead band width setting unit 52 in Fig. 2.

[0136] The third dead zone processing unit 53 is disposed before both the assist torque command value setting unit 44 and the manual steering command value generating unit 46. When the third dead zone width is W3, the third dead zone processing unit 53 calculates the steering torque T tb is within the range of -W3 / 2 or more and W3 / 2 or less (third dead band area), zero is set as the steering torque T tb,de Output as

[0137] Steering torque T tb In the region where [T tb +(W3 / 2)] is the steering torque T after the third dead band processing. tb,de The steering torque T tb In the region where [T tb -(W3 / 2)] is the steering torque T after the third dead band processing. tb,de Output as

[0138] The third dead zone width W3 is set by a third dead zone width setting unit 54. In the driving assistance mode, the third dead zone width setting unit 54 sets the third dead zone width W3 based on the hands-on / off determination result of the hands-on / off determination unit 50. In the driving assistance mode, the third dead zone width setting unit 54 performs a third dead zone width setting process for setting the third dead zone width W3.

[0139] The third dead-band width setting process performed by the third dead-band width setting unit 54 is the same as the first dead-band width setting process shown in Fig. 9. However, in the third dead-band width setting process, the first dead-band width W1 and the first dead-band width minimum value W 1_min , maximum value of first dead band width W 1_max , first dead band width reduction amount W 1_decrease and the first dead band width increase amount W 1_increase are the third dead band width W3 and the third dead band width minimum value W 3_min , the third dead band width maximum value W 3_max , third dead band width reduction amount W 3_decrease and the third dead band width increase amount W 3_increase can be replaced by

[0140] In the first modified example, the assist torque command value setting unit 44 sets the steering torque T tb,de and the vehicle speed V, the assist torque command value T * m,md The manual steering command value generating unit 46 sets the assist torque command value T * m,md and the steering torque T after the third dead band processing tb,de Based on this, the manual steering command value θ *c,md Calculate the following.

[0141] Specifically, the manual steering command value generating unit 46 calculates T tb,de After the third dead band processing, the steering torque T tb,de Substituting T in equation (2), * m,md,de The assist torque command value T * m,md By substituting and solving the differential equation (2), the rotation angle θ of the lower column is c Calculate the rotation angle θ c Actual manual steering angle θ c,md Set as.

[0142] In the driving assistance mode, when the hands-on / off determination unit 50 determines that the vehicle is in a hands-off state for a predetermined period of time or longer, the third dead zone width W3 is increased, so that the same effect as in the above-described embodiment can be obtained in the first variant.

[0143] When the operation mode is the normal mode, the third dead zone width setting unit 54 sets the third dead zone width minimum value W 3_min is set as the third dead band width W3. In other words, in the normal mode, the third dead band width W3 is not changed.

[0144] [4] Second Modification of Motor Control ECU 202 FIG. 13 is a block diagram for explaining the electrical configuration of a modified example of motor control ECU 202. In FIG.

[0145] The motor control ECU 202 includes a microcomputer 40B, a drive circuit (inverter circuit) 31 controlled by the microcomputer 40B to supply power to the electric motor 18, and a current flowing through the electric motor 18 (hereinafter referred to as the "motor current I m,int The device is provided with a current detection circuit 32 for detecting the current.

[0146] The microcomputer 40B includes a CPU and memory (ROM, RAM, nonvolatile memory, etc.), and functions as a plurality of functional processing sections by executing predetermined programs. The plurality of functional processing sections include an assist control section 111, an automatic steering control section 112, an integrated torque calculation section (integrated control amount calculation section) 113, a torque control section (control section) 114, an actual steering angle calculation section 115, a fourth dead band processing section 116, a fifth dead band processing section 117, an actual automatic steering angle calculation section 118, a hands-on / off determination section 119, a fourth dead band width setting section 120, and a fifth dead band width setting section 121.

[0147] The assist control unit 111 calculates an assist torque command value (assist control amount) T * m,md The assist control unit 111 sets the vehicle speed V and the steering torque T detected by the torque sensor 12. tb Based on this, the assist torque command value T * m,md The assist control unit 111 sets the assist torque command value T * m,md Set.

[0148] The automatic steering control unit 112 receives an automatic steering angle command value θ * c,ad and the actual automatic steering angle θ c,ad Using this, the automatic steering torque command value (automatic steering control amount) T required for automatic steering is calculated. * m,ad The automatic steering control unit 112 will be described in detail later.

[0149] The integrated torque calculation unit 113 calculates the assist torque command value T * m,md The automatic steering torque command value T * m,ad By adding these, the integrated torque command value (integrated control amount) T * m,int Calculate the following.

[0150] The torque control unit 114 controls the motor torque of the electric motor 18 to be equal to the integrated torque command value T * m,int The drive circuit 31 is driven so that the torque control section 114 approaches the torque control section 49 shown in Fig. 8. The configuration of the torque control section 114 is the same as the configuration of the torque control section 49 shown in Fig. 8, and therefore a description thereof will be omitted.

[0151] The actual steering angle calculation unit 115 calculates the rotation angle θ of the output shaft 9 based on the output signal of the rotation angle sensor 23. c,int Specifically, the actual steering angle calculation unit 115 includes a rotation angle calculation unit 115A and a reduction ratio division unit 115B. The rotation angle calculation unit 115A calculates the rotor rotation angle θ of the electric motor 18 based on the output signal of the rotation angle sensor 23. m,int The reduction ratio division unit 115B calculates the rotor rotation angle θ calculated by the rotation angle calculation unit 115A. m,int is divided by the reduction ratio N of the reducer 19, the rotor rotation angle θ m,int The rotation angle (actual steering angle) of the output shaft 9 is θ c,int Convert to.

[0152] Actual steering angle θ c,int is the steering torque T tb and the assist torque command value T * m,md The steering angle of the manual steering based on the actual manual steering angle θ c,md ") and the automatic steering torque command value T * m,ad The steering angle for automatic steering based on the actual automatic steering angle θ c,ad ").

[0153] The fourth dead zone processing unit 116 receives the steering torque T tbThe fourth dead zone processing unit 116 receives the steering torque T tb is within the range of -W4 / 2 or more and W4 / 2 or less (fourth dead band area), zero is set as the steering torque T tb,de Output as

[0154] Steering torque T tb In the region where [T tb +(W4 / 2)] is the steering torque T after the fourth dead band processing. tb,de The steering torque T tb In the region where [T tb -(W4 / 2)] is the steering torque T after the fourth dead band processing tb,de The fourth dead-band width W4 is set by the fourth dead-band width setting unit 120.

[0155] The fifth dead zone processing unit 117 receives the assist torque command value T * m,md The fifth dead zone processing unit 11 receives the assist torque command value T * m,md is within the range of -W5 / 2 or more and W5 / 2 or less (fifth dead band area), zero is set as the assist torque command value T * m,md,de Output as

[0156] Assist torque command value T * m,md In the region where [T * m,md +(W5 / 2)] is the assist torque command value T * m,md,de The assist torque command value T * m,md In the region where [T * m,md -(W5 / 2)] is the assist torque command value T* m,md,de The fifth dead zone width W5 is set by the fifth dead zone width setting unit 121.

[0157] The actual automatic steering angle calculation unit 118 calculates the actual steering angle θ c,int The actual automatic steering angle θ included in c,ad Specifically, the actual automatic steering angle calculation unit 118 includes an actual manual steering angle calculation unit 118A and a subtraction unit 118B. The actual manual steering angle calculation unit 118A calculates the steering torque T after the fourth dead zone processing. tb,de and the assist torque command value T after the fifth dead band processing * m,md,de Based on this, the actual manual steering angle θ c,md The subtraction unit 118B calculates the actual steering angle θ calculated by the actual steering angle calculation unit 115. c,int The actual manual steering angle θ calculated by the actual manual steering angle calculation unit 118A from c,md By subtracting the actual automatic steering angle θ c,ad The actual automatic steering angle θ c,ad is given to the automatic steering control unit 112.

[0158] In this embodiment, the actual manual steering angle calculation unit 118A calculates the actual manual steering angle θ using a reference model (reference EPS model) of the electric power steering system 1. c,md Calculate the following.

[0159] The actual manual steering angle calculation unit 118A calculates the actual manual steering angle θ using, for example, the reference EPS model shown in FIG. 4 described above. c,md Calculate the following.

[0160] Referring to Figure 4, the road load torque T rl is expressed by the above-mentioned formula (1) using the spring constant k and the viscous damping coefficient c. In this modified example, the spring constant k and the viscous damping coefficient c are also set in advance.

[0161] The equation of motion of the reference EPS model in FIG. 4 is expressed by the above-mentioned equation (2). The actual manual steering angle calculation unit 118A calculates T tb,deAfter the fourth dead band processing, the steering torque T tb,de Substituting T in equation (2), * m,md,de The assist torque command value T after the fifth dead band processing * m,md,de By substituting and solving the differential equation (2), the rotation angle θ of the lower column is c Calculate the rotation angle θ c Actual manual steering angle θ c,md Set as.

[0162] The hands-on / off determination unit 119 determines whether the device is in a gripped state or a hands-off state using a method similar to that used by the hands-on / off determination unit 50 in FIG.

[0163] In the driving assistance mode, the fourth dead zone width setting unit 120 and the fifth dead zone width setting unit 121 respectively set the fourth dead zone width W4 and the fifth dead zone width W5 based on the hands-on / off determination result of the hands-on / off determination unit 119. The operations of the fourth dead zone width setting unit 120 and the fifth dead zone width setting unit 121 will be described later.

[0164] The automatic steering control unit 112 will be described in detail below.

[0165] FIG. 14 is a block diagram showing the configuration of the automatic steering control unit 112.

[0166] The automatic steering control unit 112 calculates the automatic steering angle command value θ * c,ad and the actual automatic steering angle θ c,ad and the automatic steering torque command value T * m,ad The automatic steering control unit 112 includes a low-pass filter (LPF) 161, a feedback control unit 162, a feedforward control unit 163, a disturbance torque estimation unit 164, a torque addition unit 165, a disturbance torque compensation unit 166, a reduction ratio division unit 167, and a reduction ratio multiplication unit 168.

[0167] The reduction ratio multiplication unit 168 multiplies the automatic steering torque command value T *m,ad is multiplied by the reduction ratio N of the reducer 19 to obtain the automatic steering torque command value T * m,ad is the automatic output shaft torque command value N·T acting on the output shaft 9 (worm wheel 21). * m,ad (=T * c,ad )

[0168] The low-pass filter 161 detects the automatic steering angle command value θ * c,ad The automatic steering angle command value θ after low-pass filtering is * c,adf is given to the feedback control section 162 and the feedforward control section 163.

[0169] The feedback control unit 162 receives the actual automatic steering angle θ calculated by the actual automatic steering angle calculation unit 118 (see FIG. 13). c,ad is the automatic steering angle command value θ after low-pass filtering. * c,adf The feedback control unit 162 includes an angle deviation calculation unit 162A and a PD control unit 162B. The angle deviation calculation unit 162A calculates an automatic steering angle command value θ * c,adf and the actual automatic steering angle θ c,ad Deviation Δθ c,ad (=θ * c,adfd -θ c,ad ) is calculated. The angle deviation calculation unit 162A calculates the automatic steering angle command value θ * c,adf and the actual automatic steering angle estimated value ^θ calculated by the disturbance torque estimation unit 164. c,ad deviation from (θ * c,adfd -^θ c,ad ) and the angle deviation Δθ c,ad It may be calculated as:

[0170] The PD control unit 162B calculates the angle deviation Δθ calculated by the angle deviation calculation unit 162A. c,adBy performing PD calculation (proportional differential calculation) on the feedback control torque T fb,ad Calculate the feedback control torque T fb,ad is given to the torque adder 165.

[0171] The feedforward control unit 163 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 163 includes an angular acceleration calculation unit 163A and an inertia multiplication unit 163B. The angular acceleration calculation unit 163A calculates an automatic steering angle command value θ * c,adf By taking the second derivative, the target angular acceleration d 2 θ * c,adf / dt 2 Calculate the following.

[0172] The inertia multiplication unit 163B multiplies the target angular acceleration d calculated by the angular acceleration calculation unit 163A by 2 θ * c,adf / dt 2 is multiplied by the inertia J of the electric power steering system 1 to obtain the feedforward control torque T ff,ad (=J·d 2 θ * c,adf / dt 2 The inertia J can be calculated from, for example, a physical model (see FIG. 15) of the electric power steering system 1, which will be described later. The feedforward control torque T ff,ad is given to the torque adder 165 as an inertia compensation value.

[0173] The torque adder 165 calculates the feedback control torque T fb,ad to the feedforward control torque T ff,ad By adding fb,ad +T ff,ad ) is calculated.

[0174] The disturbance torque estimation unit 164 mainly estimates the disturbance torque T other than the motor torque acting on the object to be driven by the electric motor 18. lc The disturbance torque T for automatic steering included in lc,ad The automatic disturbance torque estimate ^T lc,ad The disturbance torque T for automatic steering is calculated. lc,ad The automatic steering torque command value T * m,ad This refers to torque other than the motor torque that occurs as a disturbance in the driven object (plant) of the electric motor 18 when it is assumed that only automatic steering control based on the above is being performed.

[0175] Automatic steering torque command value T * m,ad If we assume that only automatic steering control based on the above is performed, the target value of the plant is the automatic output shaft torque command value N·T * m,ad (=T * c,ad ) and the plant output is the actual automatic steering angle θ c,ad Therefore, the disturbance torque estimation unit 164 calculates the automatic output shaft torque command value N·T * m,ad (=T * c,ad ) and actual automatic steering angle θ c,ad and based on the automatic disturbance torque T lc,ad and the actual automatic steering angle θ c,ad and the actual automatic steering angle θ c,ad Derivative value (actual automatic angular velocity) dθ c,ad / dt. In the following, T lc,ad , θ c,ad and dθ c,ad / dt estimates, respectively, lc,ad , ^θ c,ad and ^dθ c,ad The disturbance torque estimation unit 164 will be described in detail later.

[0176] The automatic disturbance torque estimated value ^T calculated by the disturbance torque estimation unit 164 lc,ad is given to the disturbance torque compensator 166 as an automatic disturbance torque compensation value.

[0177] The disturbance torque compensator 166 calculates the basic torque command value (T fb,ad +T ff,ad ) to the automatic disturbance torque estimate ^T lc,ad By subtracting the automatic output shaft torque command value T * c,ad (=T fb,ad +T ff,ad -^T lc,ad ) is calculated. This results in the automatic output shaft torque command value T * c,ad (target torque for output shaft 9) is obtained.

[0178] Automatic output shaft torque command value T * c,ad is given to the reduction ratio division unit 167. The reduction ratio division unit 167 calculates the automatic output shaft torque command value T * c,ad By dividing by the reduction ratio N, the automatic steering torque command value T * m,ad (target torque for the electric motor 18). * m,ad is given to the integrated torque calculation unit 113 (see FIG. 13).

[0179] The disturbance torque estimation unit 164 will be described in detail. The disturbance torque estimation unit 164 uses, for example, a physical model 101A of the electric power steering system 1 shown in FIG. 15 to calculate an automatic disturbance torque estimated value ^T lc,ad , actual automatic steering angle estimate ^θ c,ad and actual automatic angular velocity estimate ^dθ c,ad The automatic steering torque command value T * m,ad This shows a physical model assuming that only automatic steering control based on

[0180] This physical model 101A includes a plant (an example of a motor-driven object) 102A including an output shaft 9 and a worm wheel 21 fixed to the output shaft 9. The plant 102A includes a steering torque (torsion bar torque) T tb is applied, and a road load torque T rl,ad Furthermore, the plant 102A receives an automatic output shaft torque command value N·T from the motor via the worm gear 20. * m,ad is given, and friction torque T f,ad is given.

[0181] When the inertia of the plant 102A is J, the equation of motion for the inertia of the physical model 101A is expressed by the following equation (10).

[0182]

number

[0183] d 2 θ c,ad / dt 2 is the angular acceleration of the plant 102A. N is the reduction ratio of the reducer 19. T lc,ad denotes the automatic disturbance torque applied to the plant 102A. In this embodiment, the automatic disturbance torque T lc,ad is the steering torque T tb and road load torque T rl,ad and friction torque T f,ad However, in reality, the automatic disturbance torque T lc,ad includes torques other than these.

[0184] The state equation for the physical model 101A in FIG. 15 is expressed by the following equation (11).

[0185]

number

[0186] In the above equation (11), x is a state variable vector, u1 is a known input vector, u2 is an unknown input vector, and y is an output vector. In the above equation (11), A is a system matrix, B1 is a first input matrix, B2 is a second input matrix, C is an output matrix, and D is a direct feedthrough matrix.

[0187] The state equation is expanded to a system including the unknown input vector u2 as one of the states. The state equation of the expanded system (expanded state equation) is expressed by the following equation (12).

[0188]

number

[0189] In the formula (12), x e is the state variable vector of the extended system and is expressed by the following equation (13).

[0190]

number

[0191] In the formula (12), 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.

[0192] From the extended state equation of the above-mentioned equation (12), a disturbance observer (extended state observer) expressed by the following equation (14) is constructed.

[0193]

number

[0194] In equation (14), ^x e x e represents the estimated value of . Also, L is the observer gain. Also, ^y represents the estimated value of y. ^x eis expressed by the following equation (15).

[0195]

number

[0196] In equation (15), ^θ c,ad is the actual automatic steering angle θ c,ad is the estimated value of ^dθ c,ad / dt is angular velocity dθ c,ad is an estimate of / dt, and ^T lc,ad is the automatic disturbance torque T lc,ad is an estimate of

[0197] The disturbance torque estimation unit 164 calculates the state variable vector ^x based on the equation (14). e Calculate the following.

[0198] FIG. 16 is a block diagram showing the configuration of the disturbance torque estimation unit 164.

[0199] The disturbance torque estimation unit 164 includes an input vector input unit 181, an output matrix multiplication unit 182, a first addition unit 183, a gain multiplication unit 184, an input matrix multiplication unit 185, a system matrix multiplication unit 186, a second addition unit 187, an integration unit 188, and a state variable vector output unit 189.

[0200] The automatic output shaft torque command value N·T calculated by the reduction ratio multiplication unit 168 (see FIG. 14) * m,ad (=T * c,ad ) is given to the input vector input unit 181. The input vector input unit 181 outputs the input vector u1.

[0201] The output of the integrator 188 is the state variable vector ^x e (See the above equation (15)). 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.

[0202] The system matrix multiplication unit 186 multiplies the state variable vector ^x e In the system matrix A e The output matrix multiplication unit 182 multiplies the state variable vector ^x e into the output matrix C e Multiply by.

[0203] The first adder 183 calculates the actual automatic steering angle θ c,ad From the output vector y, which is e ^x e ) is subtracted from the output vector y. That is, the first adder 183 subtracts the output vector estimate ^y(=C e ^x e ) and calculates the difference (y-^y). The gain multiplication unit 184 multiplies the output (y-^y) of the first addition unit 183 by the observer gain L (see the above equation (14)).

[0204] The input matrix multiplication unit 185 multiplies the input vector u1 output from the input vector input unit 181 by the input matrix B e The second adder 187 multiplies the output (B e u1) and the output of the system matrix multiplication unit 186 (A e ^x e ) and the output (L(y-^y)) of the gain multiplication unit 184, the differential value d^x of the state variable vector is obtained. e The integrator 188 calculates the output (d^x e / dt), the state variable vector ^x e The state variable vector output unit 189 calculates the state variable vector ^x e Based on this, the automatic disturbance torque estimate ^T lc,ad , actual automatic steering angle estimate ^θ c,ad and actual automatic angular velocity estimate d^θ c,ad Calculates / dt.

[0205] Instead of the above-mentioned extended state observer, a disturbance observer consisting of an inverse model of the plant and a low-pass filter may be used. In this case, the equation of motion of the plant is expressed by Equation (10) as described above.

[0206] Therefore, the inverse model of the plant is given by the following equation (16).

[0207]

number

[0208] The input to the disturbance observer using the inverse model of the plant is J·d 2 θ c,ad / dt 2 and N.T. * m,ad and the actual steering angle θ c,ad 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 described above estimates the disturbance torque in an integral manner, which has the advantage of reducing the influence of noise due to differentiation.

[0209] Next, the operations of the fourth dead-band width setting unit 120 and the fifth dead-band width setting unit 121 will be described. The fourth dead-band width setting unit 120 performs a fourth dead-band width setting process for setting a fourth dead-band width W4 during the driving assistance mode. The fifth dead-band width setting unit 121 performs a fifth dead-band width setting process for setting a fifth dead-band width W5 during the driving assistance mode.

[0210] The fourth dead-band width setting process performed by the fourth dead-band width setting unit 120 is the same as the first dead-band width setting process in Fig. 9. However, in the fourth dead-band width setting process, the first dead-band width W1 and the first dead-band width minimum value W 1_min , maximum value of first dead band width W 1_max , first dead band width reduction amount W 1_decrease and the first dead band width increase amount W 1_increase are the fourth dead band width W4 and the fourth dead band width minimum value W 4_min , 4th dead band width maximum value W 4_max , 4th dead band width reduction amount W4_decrease and the fourth dead band width increase amount W 4_increase can be replaced by

[0211] The fifth dead-band width setting process performed by the fifth dead-band width setting unit 121 is the same as the first dead-band width setting process in Fig. 9. However, in the fifth dead-band width setting process, the first dead-band width W1 and the first dead-band width minimum value W 1_min , maximum value of first dead band width W 1_max , first dead band width reduction amount W 1_decrease and the first dead band width increase amount W 1_increase are the fifth dead band width W5 and the fifth dead band width minimum value W 5_min , 5th dead band width maximum value W 5_max , 5th dead zone width reduction amount W 5_decrease and the fifth dead band width increase amount W 5_increase can be replaced by

[0212] In the second modification, the feedback control torque T fb,ad The automatic steering torque command value T is calculated based on the * m,ad and the assist torque command value T * m,md The integrated torque command value T * m,int Therefore, in the driving assistance mode, the electric motor 18 is driven based on the automatic steering torque command value T * m,ad The output shaft 9 is rotated based on the torque, and the steering torque T tb and the assist torque command value T * m,md The output shaft 9 is rotated based on the

[0213] In the driving assistance mode, when the hands-on / off determination unit 119 determines that the vehicle is in a hands-off state for a predetermined period of time or more, the fourth dead zone width W4 and the fifth dead zone width W5 are increased. When the fourth dead zone width W4 and the fifth dead zone width W5 are increased, the actual manual steering angle θ c,md, that is, the absolute value of the angle at which the driver is allowed to steer in response to driving assistance, becomes smaller than normal.

[0214] As a result, the actual automatic steering angle θ used for feedback control c,ad The value of becomes larger than normal, and the feedback control torque T fb,ad , automatic steering torque command value T * m,ad are transmitted in order and reflected in the torque command value of the motor.

[0215] As a result, the amount of rotation of the output shaft 9 based on the driver torque is reduced, similar to the embodiment of FIG. 2. This makes it difficult for the rotation of the steering wheel 2 to be transmitted, making it easier for the torsion bar 10 to twist. This reduces the steering torque T tb and driver torque increases, which increases the accuracy of the hands-on / off determination by the hands-on / off determination unit 119. This makes it possible to prevent or suppress erroneous determination that the driver is in a hands-off state despite gripping the steering wheel 2 in situations where the driver torque input is small, such as when driving in a straight line.

[0216] In the second modification, in the normal mode, the assist torque command value T * m,md is the integrated torque command value T * m,int Therefore, in the normal mode, the assist torque command value T * m,md The drive circuit 31 is driven based only on the signal.

[0217] [4] Third Modification of Motor Control ECU 202 Figure 17 is a block diagram for explaining the electrical configuration of a third modified example of motor control ECU 202. In Figure 17, parts corresponding to those in Figure 13 described above are denoted by the same reference numerals as in Figure 13.

[0218] In the third modified example, the configuration of the function processing units in the microcomputer 40C is different from that in Fig. 13. Specifically, in the third modified example, a sixth dead band processing unit 123 and a sixth dead band width setting unit 124 are provided instead of the fourth dead band processing unit 116, the fifth dead band processing unit 117, the fourth dead band width setting unit 120, and the fifth dead band width setting unit 121 in Fig. 13.

[0219] The sixth dead zone processing unit 123 is disposed before both the assist control unit 111 and the actual manual steering angle calculation unit 118A. When the sixth dead zone width is W6, the sixth dead zone processing unit 123 calculates the steering torque T tb is within the range of -W6 / 2 or more and W6 / 2 or less (the sixth dead band region), zero is set to the steering torque T after the sixth dead band processing. tb,de Output as

[0220] Steering torque T tb In the region where [T tb +(W6 / 2)] is the steering torque T after the 6th dead band processing. tb,de The steering torque T tb In the region where [T tb -(W6 / 2)] is the steering torque T after the sixth dead zone processing. tb,de Output as

[0221] The sixth dead zone width W6 is set by a sixth dead zone width setting unit 124. In the driving assistance mode, the sixth dead zone width setting unit 124 sets the sixth dead zone width W6 based on the hands-on / off determination result of the hands-on / off determination unit 119. In the driving assistance mode, the sixth dead zone width setting unit 124 performs a sixth dead zone width setting process for setting the sixth dead zone width W6.

[0222] The sixth dead-band width setting process performed by the sixth dead-band width setting unit 124 is the same as the first dead-band width setting process in Fig. 9. However, in the sixth dead-band width setting process, the first dead-band width W1 and the first dead-band width minimum value W 1_min , maximum value of first dead band width W 1_max, first dead band width reduction amount W 1_decrease and the first dead band width increase amount W 1_increase are the sixth dead band width W6 and the sixth dead band width minimum value W 6_min , 6th dead band width maximum value W 6_max , third dead zone width reduction amount W 6_decrease and the sixth dead band width increase amount W 6_increase can be replaced by

[0223] In the third modified example, the assist control section 111 calculates the steering torque T tb,de and the vehicle speed V, the assist torque command value T * m,md The actual manual steering angle calculation unit 118A sets the assist torque command value T * m,md and the steering torque T after the sixth dead band processing tb,de Based on this, the actual manual steering angle θ c,md Calculate the following.

[0224] Specifically, the actual manual steering angle calculation unit 118A calculates T tb,de The steering torque T after the sixth dead band processing tb,de Substituting T in equation (2), * m,md,de The assist torque command value T * m,md By substituting and solving the differential equation (2), the rotation angle θ of the lower column is c Calculate the rotation angle θ c Actual manual steering angle θ c,md Set as.

[0225] In the driving assistance mode, when the hands-on / off determination unit 119 determines that the vehicle is in a hands-off state for a predetermined period of time or longer, the sixth dead zone width W6 is increased, so that the third variant also achieves the same effect as the second variant described above.

[0226] In the third modification, in the normal mode, the assist torque command value T * m,md is the integrated torque command value T *m,int Therefore, in the normal mode, the assist torque command value T * m,md The drive circuit 31 is driven based only on the signal.

[0227] 2, both the first dead-band width W1 used in the first dead-band processing unit 43 and the second dead-band width W2 used in the second dead-band processing unit 45 are controlled based on the hands-on / off determination result, but only one of the first dead-band width W1 and the second dead-band width W2 may be controlled based on the hands-on / off determination result.Alternatively, only one of the first dead-band processing unit 43 and the second dead-band processing unit 45 may be provided, and the dead band used in that dead-band processing unit may be controlled based on the hands-on / off determination result.

[0228] 13, both the fourth dead band width W4 used in the fourth dead band processing unit 116 and the fifth dead band width W5 used in the fifth dead band processing unit 117 are controlled based on the hands-on / off determination result, but only one of the fourth dead band width W4 and the fifth dead band width W5 may be controlled based on the hands-on / off determination result.Alternatively, only one of the fourth dead band processing unit 116 and the fifth dead band processing unit 117 may be provided, and the dead band used in that dead band processing unit may be controlled based on the hands-on / off determination result.

[0229] In the above embodiment, an example was shown in which the present invention is applied to motor control of a column-type EPS, but the present invention can also be applied to motor control of EPS other than column types.

[0230] Although the embodiments of the present invention have been described in detail, these are merely examples used to clarify the technical contents of the present invention, and the present invention should not be construed as being limited to these examples, and the scope of the present invention is limited only by the appended claims. [Explanation of symbols]

[0231] 1...electric power steering device, 3...steered wheels, 4...steering mechanism, 18...electric motor, 43...first dead zone processing unit, 44...assist torque command value setting unit, 45...second dead zone processing unit, 46...manual steering command value generation unit, 47...integrated angle command value calculation unit, 48...angle control unit, 49...torque control unit, 50...hands on / off determination unit, 51...first dead zone width setting unit, 52...second dead zone width setting unit, 53...third dead zone width processing unit, 54...third dead zone width setting unit, 111...assist control unit, 112...automatic steering control unit, 113...integrated torque calculation unit (integrated control amount calculation unit), 114...torque control unit (control unit), 115...actual steering angle calculation unit, 116...fourth dead band processing unit, 117...fifth dead band processing unit, 118...actual automatic steering angle calculation unit, 118A...actual manual steering angle calculation unit, 118B...subtraction unit, 119...hands on / off determination unit, 120...fourth dead band width setting unit, 121...fifth dead band width setting unit, 122...sixth dead band width processing unit, 123...sixth dead band width setting unit, 201...host ECU 201, 202...motor control ECU

Claims

1. a torque detection unit for detecting a steering torque; an assist torque command value setting unit that sets an assist torque command value using the steering torque; a manual steering command value generating unit that generates a manual steering command value using the steering torque and the assist torque command value; an integrated angle command value calculation unit that calculates an integrated angle command value by adding the manual steering command value to an automatic steering command value given in a driving assistance mode; a control unit that controls the angle of an electric motor for steering angle control based on the integrated angle command value; a hands-on / off determination unit that determines whether the driver is in a gripped state where the driver is gripping the steering wheel or in a hands-off state where the driver is not gripping the steering wheel; a dead band processing unit provided for at least one of the steering torque input to the manual steering command value generation unit, the assist torque command value input to the manual steering command value generation unit, and the steering torque input to the assist torque command value setting unit; a dead zone width setting unit that changes the dead zone width of at least one of the dead zone processing units when the hands-on / off determination unit determines that the vehicle is in a hands-off state for a predetermined period of time or more during the driving assistance mode.

2. A motor control device including: a torque detection unit for detecting steering torque; a steering angle detection unit for detecting an actual steering angle; an automatic steering control unit for setting an automatic steering control amount based on an automatic steering command value given in a driving assistance mode; an assist control unit for setting an assist control amount using the steering torque; an integrated control amount calculation unit for calculating an integrated control amount by adding the automatic steering control amount and the assist control amount; and a control unit for controlling an electric motor for steering angle control based on the integrated control amount, a hands-on / off determination unit that determines whether the driver is in a gripped state where the driver is gripping the steering wheel or in a hands-off state where the driver is not gripping the steering wheel; an actual manual steering angle calculation unit that calculates an actual manual steering angle, which is a steering angle for manual steering based on the steering torque and the assist control amount; an actual automatic steering angle calculation unit that calculates an actual automatic steering angle, which is a steering angle for automatic steering based on the automatic steering control amount, by subtracting the actual manual steering angle from the actual steering angle, the automatic steering control unit is configured to set the automatic steering control amount using the automatic steering command value and the actual automatic steering angle, a dead band processing unit provided for at least one of the steering torque input to the actual manual steering angle calculation unit, the assist control amount input to the actual manual steering angle calculation unit, and the steering torque input to the assist control unit; a dead zone width setting unit that changes the dead zone width of at least one of the dead zone processing units when the hands-on / off determination unit determines that the vehicle is in a hands-off state for a predetermined period of time or more during the driving assistance mode.

3. When the dead-zone processing unit whose dead-zone width is changed by the dead-zone width setting unit is a variable dead-zone processing unit, 3. The motor control device according to claim 1, wherein the dead zone width setting unit is configured to increase the dead zone width of the variable dead zone processing unit when the hands-on / off determination unit determines that the vehicle is in a hands-off state for a predetermined period of time or more during the driving assistance mode.

4. 4. The motor control device according to claim 3, wherein, when the hands-on / off determination unit determines that the vehicle is in a hands-off state for a predetermined period of time during the driving assistance mode, the dead zone width setting unit gradually increases the dead zone width from that point on while the hands-on / off determination unit determines that the vehicle is in a hands-off state, and when the dead zone width reaches a predetermined upper limit value, the dead zone width is maintained at the upper limit value.

5. 5. The motor control device according to claim 4, wherein, in the driving assistance mode, when the hands-on / off determination unit determines that the vehicle is in a hands-off state for a predetermined period of time or more and then changes the determination result by the hands-on / off determination unit to a gripped state, the dead zone width setting unit gradually reduces the dead zone width from that point onwards while the determination result that the vehicle is in a gripped state continues, and when the dead zone width reaches a predetermined lower limit value, the dead zone width is maintained at the lower limit value.

Images