WO2023079764A1

WO2023079764A1 - Motor control device

Info

Publication number: WO2023079764A1
Application number: PCT/JP2021/041058
Authority: WO
Inventors: 悠太酒井; 勉田村; ロバートフックス
Original assignee: 株式会社ジェイテクト
Priority date: 2021-11-08
Filing date: 2021-11-08
Publication date: 2023-05-11

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

motor controller

The present invention relates to a motor control device that controls an electric motor for steering angle control.

Patent Document 1 discloses the following driving assistance technology. That is, the steering control unit calculates the X-coordinate xc of the target passing point and the X-coordinate xe of the estimated passing point at the forward gaze distance. Then, the steering control unit has an operational term obtained by multiplying the deviation (xc-xe) between these X coordinates xc and xe by a first control gain Gl, and an operational term obtained by multiplying the yaw angle θca by a second control gain Gy. are added to calculate the control amount (torque command value) Tc of the motor. The first and second control gains Gl and Gy are set to larger values as the hands-off time is longer, and are set to smaller values as the arousal level is lower or the carelessness level is higher when the hands-free state is not detected. be.

JP 2011-57037 A

The driver's grip on the steering wheel is a prerequisite for driving support functions equivalent to Level 2. Therefore, in the driving assistance mode, if the determination result of the hands-free state continues for a predetermined time or longer, a warning is output, and if the hands-free state continues after the warning, the driving assistance mode is canceled.

For this reason, in the driving support mode, it is necessary to accurately determine whether the user is in a gripping state or in a hands-free state. However, when it is determined whether the driver is in the gripped state or the hands-free state based on the steering torque (torsion bar torque) detected by the torque sensor, the driver may not be able to grip the steering wheel in a situation where the driver torque input is small, such as when driving in a straight line. There is a possibility that it may be erroneously determined that the user is in the hands-free state even though the user is doing so.

An object of an embodiment of the present invention is to provide a motor control device that can accurately determine whether the vehicle is in a gripping state or a hands-free state in a driving assistance mode.

An 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, the steering torque and the assist torque command value. A manual steering command value generation unit that generates a manual steering command value using and an integrated angle that calculates an integrated angle command value by adding the manual steering command value to the automatic steering command value given in the driving support mode a command value calculation unit; a control unit that performs angle control of an electric motor for steering angle control based on the integrated angle command value; the steering torque input to the manual steering command value generating unit, the assist torque command value input to the manual steering command value generating unit, and the a plurality of dead zone processors provided for at least one of the steering torques input to the assist torque command value calculator; and a dead zone width setting section for changing the dead zone width of at least one of the dead zone processing sections when the above continues for a predetermined time or more.

With this configuration, it is possible to accurately determine whether the gripping state or the hands-free state is in the driving support mode.

An embodiment of the present invention includes a torque detection section for detecting steering torque, a steering angle detection section for detecting an actual steering angle, and automatic steering control based on an automatic steering command value given during a driving assistance mode. an automatic steering control unit that sets the steering torque; an assist control unit that sets an assist control amount using the steering torque; and an integrated control amount is calculated by adding the automatic steering control amount and the assist control amount. A motor control device including an integrated control amount calculation unit and a control unit that controls an electric motor for steering angle control based on the integrated control amount, and is in a gripping state in which a driver is gripping a steering wheel. a hands-on/off determination unit that determines whether the driver is in a hands-off state in which the driver does not grip the steering wheel; and an actual automatic steering angle calculator for calculating 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; and the actual manual steering angle calculation unit a dead zone processing unit provided in 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 section for changing the dead zone width of at least one dead zone processing section of the dead zone processing section when the determination result of the hands-on/off determination section that the hands are released is continued for a predetermined time or longer in the mode. A motor controller is provided, further comprising:

The above and further objects, features and effects of the present invention will be made clear by the following description of the embodiments with reference to the accompanying drawings.

FIG. 1 is a schematic diagram showing a schematic configuration of an electric power steering system to which a motor control device according to an embodiment of the invention is applied. FIG. 2 is a block diagram for explaining the electrical configuration of the motor control ECU. FIG. 3 is a graph showing a setting example of the assist torque command value T ^* _m,ad with respect to the steering torque _Ttb . FIG. 4 is a schematic diagram showing an example of a reference EPS model used in the manual steering command value setting section. FIG. 5 is a block diagram showing the configuration of the angle control section. FIG. 6 is a schematic diagram showing a configuration example of a physical model of the electric power steering system. FIG. 7 is a block diagram showing the configuration of the disturbance torque estimator. FIG. 8 is a schematic diagram showing the configuration of the torque control section. FIG. 9 is a flow chart showing the procedure of the first dead zone width setting process performed by the first dead zone width setting section. FIG. 10 is a graph showing an example of input/output characteristics of the first dead band width setting section. FIG. 11 is a time chart showing an example of changes in the first dead zone width _W1 in the driving assistance mode. FIG. 12 is a block diagram for explaining the electrical configuration of the first modified example of the motor control ECU. FIG. 13 is a block diagram for explaining the electrical configuration of a second modification of the motor control ECU. FIG. 14 is a block diagram showing the configuration of the automatic steering control section. FIG. 15 is a schematic diagram showing a configuration example of a physical model of the electric power steering system. FIG. 16 is a block diagram showing the configuration of the disturbance torque estimator. FIG. 17 is a block diagram for explaining the electrical configuration of a third modification of the motor control ECU.

[Description of the embodiment of the present invention]
An 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, the steering torque and the assist torque command value. A manual steering command value generation unit that generates a manual steering command value using and an integrated angle that calculates an integrated angle command value by adding the manual steering command value to the automatic steering command value given in the driving support mode a command value calculation unit; a control unit that performs angle control of an electric motor for steering angle control based on the integrated angle command value; the steering torque input to the manual steering command value generating unit, the assist torque command value input to the manual steering command value generating unit, and the a dead zone processor provided for at least one of the steering torques input to the assist torque command value calculator; and a dead zone width setting section for changing the dead zone width of at least one of the dead zone processing sections when the operation continues for a period of time or more.

In one embodiment of the present invention, when the dead zone processing section whose dead zone width is changed by the dead zone width setting section is a dead zone processing section with a variable dead zone width, the dead zone width setting section, in the driving support mode, The dead zone width variable dead zone processing part is configured to increase the dead zone width when the hands-on/off judging part continues for a predetermined period of time or more to determine that the hands are in the hands-free state.

In one embodiment of the present invention, the dead band width setting unit is in the hands-free state from that point in time when the hands-on/off determination unit determines that the hands-on state is in the hands-free state for a predetermined period of time in the driving assistance mode. While the determination result continues, the dead zone width is gradually increased, and when the dead zone width reaches a predetermined upper limit value, the dead zone width is held at the upper limit value.

In one embodiment of the present invention, the dead band width setting unit, in the driving assistance mode, after the hands-on-off determination unit determines that the hands are released for a predetermined time or longer, the hands-on-off determination unit When the determination result changes to the gripping state, the dead zone width is gradually decreased while the determination result indicating the gripping state continues from that time point, and when the dead zone width reaches a predetermined lower limit value, The dead band width is held at the lower limit.

[Detailed Description of Embodiments of the Invention]
BEST MODE FOR CARRYING OUT THE INVENTION Below, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

[1] Schematic Configuration of Electric Power Steering System FIG. 1 is a schematic diagram showing a schematic configuration of an electric power steering system to which a motor control device according to an embodiment of the present invention is applied.

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

The steering shaft 6 includes an input shaft 8 connected to the steering wheel 2 and an output shaft 9 connected to the intermediate shaft 7. The input shaft 8 and the output shaft 9 are connected via a torsion bar 10 so as to be relatively rotatable.

A torque sensor (torque detector) 12 is arranged near the torsion bar 10 . The torque sensor 12 detects a steering torque (torsion bar torque) _Ttb applied to the steering wheel 2 based on relative rotational displacement amounts of the input shaft 8 and the output shaft 9 . In this embodiment, the steering torque _Ttb detected by the torque sensor 12 is, for example, a positive value for torque for steering to the left and a negative value for torque for steering to the right. , and the magnitude of the steering torque _Ttb increases as the absolute value increases.

The steering mechanism 4 consists 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 steering of the steering wheel 2 . A pinion 16 is connected to the tip of the pinion shaft 13 .

The rack shaft 14 extends linearly along the lateral direction of the vehicle. A rack 17 that meshes with the pinion 16 is formed in the axially intermediate portion of the rack shaft 14 . The pinion 16 and 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 steerable wheels 3 can be steered.

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. Rotation of the pinion shaft 13 is converted into axial movement of the rack shaft 14 by the pinion 16 and the rack 17 . As a result, the steerable wheels 3 are steered.

The steering assist mechanism 5 includes an electric motor 18 for generating a steering assist force (assist torque) and a speed reducer 19 for amplifying the output torque of the electric motor 18 and transmitting it to the steering mechanism 4 . The speed reducer 19 comprises a worm gear mechanism including a worm gear 20 and a worm wheel 21 meshing with the worm gear 20 . The speed reducer 19 is accommodated in a gear housing 22 as a transmission mechanism housing. In the following, the reduction ratio (gear ratio) of the speed reducer 19 may be represented by N. The reduction ratio N is defined as the ratio θ _wg /θ _ww of the rotation angle θ _wg of the worm gear 20 to the rotation angle θ _ww of the worm wheel 21 .

The worm gear 20 is rotationally driven by the electric motor 18 . Also, the worm wheel 21 is connected to the output shaft 9 so as to be rotatable together.

When the worm gear 20 is rotationally driven by the electric motor 18, the worm wheel 21 is rotationally driven, motor torque is applied to the steering shaft 6, and the steering shaft 6 (output shaft 9) rotates. Rotation of the steering shaft 6 is transmitted to the pinion shaft 13 via the intermediate shaft 7 . Rotation of the pinion shaft 13 is converted into axial movement of the rack shaft 14 . As a result, the steerable wheels 3 are steered. That is, by rotationally driving the worm gear 20 with the electric motor 18, the steering assistance with the electric motor 18 and the steering of the steerable 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 .

The torque applied to the output shaft 9 (an example of the object to be driven by the electric motor 18) includes motor torque by the electric motor 18 and disturbance torque other than the motor torque. The disturbance torque T _lc other than the motor torque includes steering torque T _tb , road load torque (road surface reaction torque) T _rl , friction torque T _f and the like.

The steering torque _Ttb is a torque applied to the output shaft 9 from the steering wheel 2 side by force applied to the steering wheel 2 by the driver (driver torque), force generated by steering inertia, or the like.

The road load torque _Trl is generated by the self-aligning torque generated in the tire, the force generated by the suspension and tire wheel alignment, the frictional force of the rack and pinion mechanism, and the like. is the torque applied to

The vehicle has a CCD (Charge Coupled Device) camera 25 that captures the road in front of the vehicle, a GPS (Global Positioning System) 26 that detects the position of the vehicle, and a radar that detects road shapes and obstacles. 27, a map information memory 28 storing map information and a vehicle speed sensor 29 for detecting vehicle speed V are mounted.

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 driving support control. Based on the information and map information obtained by the CCD camera 25, the GPS 26, the radar 27 and the vehicle speed sensor 29, the host ECU 201 recognizes the surrounding environment, estimates the position of the vehicle, plans routes, etc., and determines control target values for steering and drive actuators. make a decision.

In this embodiment, there are a normal mode and a driving support mode as the driving modes. The host ECU 201 sets an automatic steering command value θ ^* _c,ad for driving assistance in the driving assistance mode. In this embodiment, the driving assistance is Lane Centering Assist (LCA) to keep the vehicle position in the middle of the lane (lane center). The automatic steering command value θ ^* _c,ad is a target steering angle value for driving the vehicle along the center of the lane. The automatic steering command value θ ^* _c,ad is set based on, for example, the vehicle speed, the lateral deviation from the target travel line, and the yaw deviation of the vehicle from the target travel line. Since the processing for setting the automatic steering command value θ ^* _c,ad is well known, detailed description thereof will be omitted here. In the normal mode, the host ECU 201 sets the automatic steering command value θ ^* _c,ad to zero.

The host ECU 201 also outputs a mode signal S _mode indicating whether the driving mode is the normal mode or the driving assistance mode. The mode signal S _mode , the automatic steering command value θ ^* _c,ad set by the host ECU 201, and the vehicle speed V are given to the motor control ECU 202 via the vehicle-mounted network. The steering torque T _tb detected by the torque sensor 12 and the output signal of the rotation angle sensor 23 are input to the motor control ECU 202 . The motor control ECU 202 controls the electric motor 18 based on these input signals and information given from the host ECU 201 .

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

The motor control ECU 202 includes a microcomputer 40, a drive circuit (inverter circuit) 31 that is controlled by the microcomputer 40 to supply electric power to the electric motor 18, and a current flowing through the electric motor 18 (hereinafter referred to as "motor current _{Im, int} ”).

The microcomputer 40 has a CPU and memory (ROM, RAM, non-volatile memory, etc.), and functions as a plurality of functional processing units by executing predetermined programs. The plurality of function processing units include a rotation angle calculation unit 41, a reduction ratio division unit 42, a first dead zone processing unit 43, an assist torque command value setting unit 44, a second dead band processing unit 45, a manual steering A command value generation unit 46, an integrated angle command value calculation unit 47, an angle control unit 48, a torque control unit 49, a hands-on/off determination unit 50, a first dead band width setting unit 51, and a second dead band width setting unit 52 are included.

The rotation angle calculator 41 calculates the rotor rotation angle θ _m,int of the electric motor 18 based on the output signal of the rotation angle sensor 23 . A reduction ratio dividing unit 42 divides the rotor rotation angle θm _,int by the reduction ratio N to convert the rotor rotation angle θm _,int into the rotation angle (actual steering angle) _θc,int of the output shaft 9. .

The steering torque _Ttb is input to the first dead zone processor 43 . When the steering torque T _tb is within the range of -W ₁ /2 or more and W ₁ /2 or less (first dead zone region), the first dead zone processing unit 43, where W ₁ is the first dead zone width, Zero is output as the steering torque Ttb _,de after the first dead zone processing (see FIG. 10 described later).

In a region where the steering torque T _tb is smaller than −W ₁ /2, the first dead zone processing unit 43 sets [T _tb +(W ₁ /2)] as the steering torque T _tb,de after the first dead zone processing. Output. In a region where the steering torque T _tb is greater than W ₁ /2, the first dead zone processing unit 43 outputs [T _tb - (W ₁ /2)] as the steering torque T _tb,de after the first dead zone processing. do. The first dead zone width _W1 is set by the first dead zone width setting section 51 .

The assist torque command value setting unit 44 sets assist torque command values T ^* _{m and md,} which are target values of assist torque required for manual operation. The assist torque command value setting unit 44 sets assist torque command values T ^* _{m and md} based on the vehicle speed V and the steering torque _Ttb detected by the torque sensor 12 . A setting example of the assist torque command values T ^* _{m, md} with respect to the steering torque _Ttb is shown in FIG.

The assist torque command values T ^* _{m, md} are positive values when the electric motor 18 is to generate a steering assist force for left steering, and the electric motor 18 generates a steering assist force for right steering. Negative value when it should. The assist torque command values T ^* _{m, md} are positive for a positive value of the steering torque _Ttb and negative for a negative value of the steering torque _Ttb . The assist torque command values T ^* _{m, md} are set such that the absolute value thereof increases as the absolute value of the steering torque _Ttb increases. The assist torque command values T ^* _{m, md} are set such that the higher the vehicle speed V, the smaller the absolute value thereof.

The assist torque command value setting unit 44 may calculate the assist torque command values T ^* _{m, md} by multiplying the steering torque _Ttb by a preset constant.

The assist torque command values T ^* _{m, md} are input to the second dead zone processing unit 45 . Assuming that the second dead band width is W 2 , the second dead band processing unit ₄₅ adjusts the assist torque command value T ^* _{m, md} within the range of −W ₂ /2 or more and W ₂ /2 or less (second dead band region). In some cases, zero is output as the assist torque command value T ^* _m,md,de after the second dead zone processing.

In a region where the assist torque command values T ^* _{m, md} are smaller than −W ₂ /2, the second dead zone processing unit 45 calculates [T ^* _{m, md} + (W ₂ /2)] after the second dead zone processing. are output as assist torque command values T ^* _{m, md, and de} . In a region where the assist torque command values T ^* _m,md are greater than W ₂ /2, the second dead zone processing unit 45 converts [T ^* _m,md− (W ₂ /2)] to They are output as assist torque command values T ^* _{m, md, and de} . The second dead band width _W2 is set by the second dead band width setting unit 52 .

The manual steering command value generator 46 is provided to set the steering angle corresponding to the steering wheel operation as manual steering command values θ ^* _{c, md} when the driver operates the steering wheel 2 . The manual steering command value generator 46 generates the manual steering command value θ ^* using the steering torque _Ttb,de after the first dead band processing and the assist torque command value T ^* _{m, md, de} after the second dead band processing. Generate _{c and md} . In this embodiment, the manual steering command value generator 46 uses the reference EPS model to generate the manual steering command value θ ^* _c. Set _md .

FIG. 4 is a schematic diagram showing an example of the reference EPS model used in the manual steering command value generator 46. FIG.

This reference EPS model is a single inertia model that includes a lower column. A lower column corresponds to the output shaft 9 and the worm wheel 21 . In FIG. 4, _Jc is the inertia of the lower column, _θc is the rotation angle of the lower column, and Ttb _,de is the steering torque after the first dead zone processing. This reference EPS model is a torque acting on the output shaft 9 from the electric motor 18 based on the steering torque Ttb _,de after the first dead band processing and the assist torque command value T ^* _{m, md, de} after the second dead band processing. This is a model for generating (estimating) the rotation angle _θc of the lower column when N·T ^* _{m, md, de} and road load torque _Trl are applied to the lower column. A road load torque _Trl is expressed by the following equation (1) using a spring constant k and a viscous damping coefficient c.

T _rl =−k·θ _c −c(dθ _c /dt) (1)
In this embodiment, the spring constant k and the viscous damping coefficient c are set to predetermined values obtained in advance through experiments, analyses, or the like.

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

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 generator 46 calculates the rotation angle _θc of the lower column by solving the differential equation of equation (2). Then, the manual steering command value generator 46 sets the obtained rotation angle _θc of the lower column as the manual steering command value θ ^* _c,md .

The integrated angle command value calculation unit 47 adds the manual steering command value θ*c, _md to the automatic steering command value θ ^* _c,ad set by the host ECU 201 to calculate the integrated angle command value θ ^* _c,int ^. do.

The angle control unit 48 calculates a motor torque command value T ^* m _,int , which is a target value of the motor torque of the electric motor 18, based on the integrated angle command value θ ^* c _,int . The torque control unit 49 drives the drive circuit 31 so that the motor torque of the electric motor 18 approaches the motor torque command value T ^* _m,int . That is, the control unit including the angle control unit 48 and the torque control unit 49 controls the actual steering angle θ _c,int (the rotation angle θ _c,int of the output shaft 9) to approach the integrated angle command value θ ^* _c,int. , drive and control the drive circuit 31 . Details of the operations of the angle control section 48 and the torque control section 49 will be described later.

The hands-on/off determination unit 50 determines whether the driver is gripping the steering wheel 2 (hands-on) or the driver is not gripping the steering wheel 2 (hands-off). The hands-on/off determination unit 50 estimates the driver torque, which is the torque applied to the steering wheel 2 by the driver, based on, for example, the steering torque _Ttb and the actual steering angle _θc,int or the rotor rotation angle _θm,int. If the driver torque is equal to or greater than a predetermined threshold value, it may be determined that the gripped state is present, and if the driver torque is less than the threshold value for a predetermined time or longer, it may be determined that the hand is released. In this case, after the driver torque changes from a state equal to or greater than the threshold value to less than the threshold value, it is determined to be in the gripping state until it is determined to be in the hands-free state.

As such a hands-on/off determination unit 50, for example, A "steering wheel operation state determination unit" described in JP-A-2003-200053 or the like can be used.

For _example , if the steering torque _Ttb is equal to or greater than a predetermined threshold value, the hands-on/off determination unit 50 determines that the gripping state is established. It may be determined that there is. In this case, after the steering torque _Ttb changes from the threshold value or more to less than the threshold value, the gripping state is determined until the hands-free state is determined.

A first dead band width setting unit 51 and a second dead band width setting unit 52 respectively set a first dead band width _W1 and a second dead band width W based on the hands-on/off determination result of the hands-on/off determination unit 50 in the driving assistance mode. Set ₂ . The details of the operations of the first dead band width setting section 51 and the second dead band width setting section 52 will be described later.

FIG. 5 is a block diagram showing the configuration of the angle control section 48. As shown in FIG.

The angle control unit 48 calculates a motor torque command value T ^* m _{, int} based on the integrated angle command value θ ^* c _{, 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, and a reduction ratio division. A section 67 and a speed reduction ratio multiplication section 68 are included.

The reduction ratio multiplication unit 68 multiplies the motor torque command value T ^* _m,int calculated by the reduction ratio division unit 67 by the reduction ratio N of the reduction gear 19 to output the motor torque command value T ^* _m,int . Convert to an output shaft torque command value T ^* _c,int (=N·T ^* _m,int ) acting on the shaft 9 .

The low-pass filter 61 performs low-pass filter processing on the integrated angle command value θ ^* _c,int . The integrated angle command value θ ^* _{c, intf} after low-pass filtering is given to the feedback control section 62 and the feedforward control section 63 .

The feedback control unit 62 is provided to bring the actual steering angle _θc,int calculated by the reduction ratio dividing unit 42 (see FIG. 2) closer to the integrated angle command value θ ^* _c,intf after low-pass filtering. there is The feedback control section 62 includes an angular deviation calculation section 62A and a PD control section 62B. An angle deviation ^calculation unit 62A calculates a deviation Δθ _c, _int (=θ ^* c _, _intf −θ _{c, int} ). The angle deviation calculation unit 62A ^{calculates the deviation (θ*} ^c _, _intf _- ^θ _c,int ) may be calculated as the angular deviation Δθ _c,int .

The PD control section 62B calculates the feedback control torque T _fb _{,int by performing a PD calculation (proportional differential calculation) on the angular deviation Δθ c,} int calculated by the angular deviation calculating section 62A. The feedback control torque T _fb,int is applied to the torque adder 65 .

The feedforward control section 63 is provided to compensate for the response delay due to the inertia of the electric power steering system 1 and improve the control response. Feedforward control section 63 includes an angular acceleration calculation section 63A and an inertia multiplication section 63B. The angular acceleration calculator 63A calculates a target angular acceleration d ² θ ^* _c,intf /dt ² by second-order differentiating the integrated angle command value θ ^* _c, intf.

The inertia multiplier 63B multiplies the target angular acceleration d ² θ ^* _c,intf /dt ² calculated by the angular acceleration calculator 63A by the inertia J of the electric power steering system 1 to obtain the feedforward control torque _{Tff. , int} (=J·d ² θ ^* _{c, intf} /dt ² ). The inertia J is obtained, for example, from a physical model (see FIG. 6) of the electric power steering system 1, which will be described later. The feedforward control torque Tff _,int is given to the torque adder 65 as an inertia compensation value.

The torque adder 65 calculates a basic torque command value (T _fb,int +T _ff, _int ) by adding the feedforward control torque T _ff,int to the feedback control torque T fb,int .

The disturbance torque estimator 64 is provided for estimating nonlinear torque (disturbance torque: torque other than motor torque) generated as a disturbance in the plant (controlled object of the electric motor 18). The disturbance torque estimator 64 calculates the output shaft torque command value T ^* _c,int (=N·T ^* _m,int ), which is the input value to the plant, and the actual steering angle _{θc,int, which} is the output of the plant. Based on this, the disturbance torque (disturbance load) T _lc , the steering angle θ _c,int and the steering angle differential value (angular velocity) dθ _c,int /dt are estimated. Estimated values of disturbance torque T _lc , steering angle θ _c,int and steering angle differential value (angular velocity) dθ _c,int /dt are respectively given by ^T _lc , ^θ _c,int and d^θ _c,int /dt. show. Details of the disturbance torque estimator 64 will be described later.

The disturbance torque estimation value ̂T _lc calculated by the disturbance torque estimator 64 is given to the disturbance torque compensator 66 as a disturbance torque compensation value.

The disturbance torque compensator 66 subtracts the disturbance torque estimated value ̂Tlc from the basic torque command value (Tfb _,int + Tff _,int ) to obtain the output shaft torque command value T ^* _c _,int (=Tfb _{, int} +T _{ff, int} −̂T _lc ). As a result, the output shaft torque command value T ^* _c,int (torque command value for the output shaft 9) in which the disturbance torque is compensated is obtained.

The output shaft torque command value T ^* _c,int is given to the reduction ratio dividing section 67 . A reduction ratio division unit 67 divides the output shaft torque command value T ^* _c,int by the reduction ratio N to calculate a 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).

The disturbance torque estimator 64 will be described in detail. The disturbance torque estimator 64 uses, for example, the physical model 101 _of the electric power _steering system 1 _shown in FIG. Consists of observers.

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 is provided with a steering torque _Ttb from the steering wheel 2 through the torsion bar 10 and a road load torque _Trl from the steered wheels 3 side.

Further, the plant 102 is given an output shaft torque command value T ^* _c,int (=N·T ^* _m,int ) via the worm gear 20, and the friction between the worm wheel 21 and the worm gear 20 causes friction A torque _Tf is applied.

Assuming that 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).

d ² θ _c,int /dt ² is the angular acceleration of plant 102 . N is the speed reduction ratio of the speed reducer 19 . _Tlc indicates disturbance torque other than the motor torque applied to the plant 102 . In this embodiment, the disturbance torque _Tlc is shown as the sum of the steering torque _Ttb , _the road load torque _Trl , and the friction torque _Tf . contains.

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

In the above equation (4), x is a state variable vector, _u1 is a known input vector, _u2 is an unknown input vector, and y is an output vector (measured value). (4), A is the system matrix, _B1 is the first input matrix, _B2 is the second input matrix, C is the output matrix, and D is the feedthrough matrix.

We extend the above state equation to a system that includes the unknown input vector _u2 as one of the states. The state equation of the extended system (extended state equation) is represented by the following equation (5).

In the above equation (5), x _e is a state variable vector of the extended system and is expressed by the following equation (6).

In the above equation (5), A _e is a system matrix of the extended system, B _e is a known input matrix of the extended system, and C _e is an output matrix of the extended system.

A disturbance observer (extended state observer) represented by the following equation (7) is constructed from the extended state equation of equation (5) above.

In equation (7), ̂x _e represents the estimated value of x _e . Also, L is an observer gain. Also, ^y represents the estimated value of y. ^x _e is represented by the following equation (8).

In equation (8), ̂θc _,int is the estimated value of θc _,int , and _̂Tlc is the estimated value of _Tlc .

The disturbance torque estimator 64 calculates the state variable vector _̂xe based on the equation (7).

FIG. 7 is a block diagram showing the configuration of the disturbance torque estimator 64. As shown in FIG.

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 It includes an addition section 87 , an integration section 88 and a state variable vector output section 89 .

The output shaft torque command value T ^* _c,int (=N·T ^* _m,int ) calculated by the reduction ratio multiplication section 68 (see FIG. 5) is given to the input vector input section 81 . The input vector input unit 81 outputs an input vector _u1 .

The output of the integrator 88 is the state variable vector ̂x _e (see equation (8) above). At the start of computation, an initial value is given as the state variable vector _̂xe . The initial value of the state variable vector ̂x _e is 0, for example.

A system matrix multiplier 86 multiplies the state variable vector ̂x _e by the system matrix A _e . The output matrix multiplier 82 multiplies the state variable vector ̂x _e by the output matrix C _e .

The first adder 83 converts the output vector (measured value) y, which is the actual steering angle θ _c,int calculated by the reduction ratio divider 42 (see FIG. 2), to the output (C _e · ^x _e ). That is, the first adder 83 calculates the difference (y−̂y) between the output vector y and the output vector estimated value ̂y (=C _e ·̂x _e ). The gain multiplier 84 multiplies the output (y−̂y) of the first adder 83 by the observer gain L (see the above equation (7)).

The input matrix multiplication unit 85 multiplies the input vector u1 output from the input vector input unit ₈₁ by the input matrix _Be . The second adder 87 outputs the output (Be·u ₁ ) of the input matrix multiplier 85, the output (A _e ·̂x _e ) of the system matrix multiplier 86, and the output of the gain multiplier 84 (L(y− ̂y)) is added to calculate the differential value d̂x _e /dt of the state variable vector. The integrator 88 calculates the state variable vector ̂x _e by integrating the output (d̂x _e /dt) of the second adder 87 . A state variable vector output unit 89 calculates an estimated disturbance torque value ̂T _lc , an estimated steering angle value ̂θ _c,int, and an estimated angular velocity value d̂θ _c,int /dt based on the state variable vector ̂x _e . .

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 becomes the following equation (9).

Inputs to a general disturbance observer are J·d ² θ _c,int /dt ² and N·T ^* _{m, int} _. 23 noise. On the other hand, in the extended state observer of the above-described embodiment, since the disturbance torque is estimated in an integral manner, the noise effect due to differentiation can be reduced.

As the disturbance torque estimator 64, a general disturbance observer composed of an inverse model of the plant and a low-pass filter may be used.

FIG. 8 is a block diagram showing the electrical configuration of the torque control section 49. As shown in FIG. Torque controller 49 includes a motor current command value calculator 91 , a current deviation calculator 92 , a PI controller 93 , and a PWM (Pulse Width Modulation) controller 94 .

The motor current command value calculation unit 91 divides the motor torque command value T ^* _m,int calculated by the angle control unit 48 by the torque constant _Kt of the electric motor 18 to obtain the motor current command value I ^* _m,int. to calculate

^A current deviation calculator 92 calculates a deviation ΔI _m _,int ₍ =I ^* _m,int - _Im,int ).

The PI control unit 93 performs PI calculation (proportional-integral calculation) on the current deviation ΔI _m,int calculated by the current deviation calculation unit 92, thereby converting the motor current _{Im, int} flowing through the electric motor 18 into the motor current command value. Generate a drive command value for leading to I ^* _m,int . The PWM control section 94 generates a PWM control signal having a duty ratio corresponding to the drive command value, and supplies it to the drive circuit 31 . As a result, electric power corresponding to the drive command value is supplied to the electric motor 18 .

Next, operations of the first dead band width setting section 51 and the second dead band width setting section 52 will be described in detail. The first dead zone width setting unit 51 performs a first dead zone width setting process for setting the first dead zone width _W1 in the driving support mode. The second dead band width setting unit 52 performs a second dead band width setting process for setting the second dead band width _W2 in the driving support mode.

FIG. 9 is a flowchart showing the procedure of the first dead zone width setting process performed by the first dead zone width setting section 51. FIG. The first dead band width setting process shown in FIG. 9 is started each time the driving assistance mode is started, and is repeatedly performed at predetermined calculation cycles until the driving assistance mode is canceled.

In the following, ΔT is the time (sampling time) corresponding to one calculation cycle. T _off is the duration of the hands-free state. _{W1_min} is a preset minimum value of the first dead zone width _W1 (hereinafter referred to as “first dead zone width minimum value _{W1_min} ”). The normal value of the first dead band width _W1 is set as the minimum first dead band width W1 _,min . _{W1_max} is the preset maximum value of the first dead zone width _W1 (hereinafter referred to as "first dead zone width maximum value _{W1_max} "). _{W1_decrease} is a first dead band width decrease amount in a preset one calculation cycle. _{W1_increase} is the amount of increase in the width of the first dead band in one calculation cycle set in advance. The initial value of _W1 is _{W1_min} . The initial value of _Toff is zero.

The first dead band width setting unit 51 determines whether or not the determination result of the hands-on/off determination unit 50 is the hands-free state (step S1).

If the determination result of the hands-on/off determining unit 50 is the gripping state (step S1: NO), the first dead zone width setting unit 51 sets the duration _Toff of the hands-free state to zero (step S2). Then, the first dead band width setting unit 51 determines whether or not the first dead band width _W1 is larger than the first dead band width minimum value _{W1_min} (step S3).

When the first dead band width _W1 is greater than the first dead band width minimum value _{W1_min} (step S3: YES), the first dead band width setting unit 51 sets the first dead band width decrease amount from the first dead band width _W1. The value obtained by subtracting _{W1_decrease} is set as the first dead zone width _W1 (step S4). However, when the value obtained by subtracting the first dead band width decrease amount _{W1_decrease} from the first dead band width _W1 is smaller than the first dead band width minimum value _{W1_min} , the first dead band width setting unit 51 sets the first dead band width The width minimum value _{W1_min} is set as the first dead zone width _W1 . Then, the first dead band width setting unit 51 ends the processing in the current calculation cycle.

When it is determined in step S3 that the first dead band width _W1 is equal to or less than the first dead band width minimum value _{W1_min} (step S3: NO), the first dead band width setting unit 51 sets the first dead band width minimum The value _{W1_min} is set as the first dead zone width _W1 (step S5). Then, the first dead band width setting unit 51 ends the processing in the current calculation cycle.

In step S1, when the determination result of the hands-on/off determination unit 55 is determined to be the hands-free state (step S1: YES), the first dead band width setting unit 51 adds ΔT to the hands-free state duration _Toff . The added value is set to _Toff (step S6). That is, the duration _Toff of the hands-free state is updated.

Next, the first dead band width setting unit 51 determines whether or not the duration _Toff of the hands-free state is longer than the predetermined time _{T_start} (step S7). If the continuation time T _off of the hands-free state is equal to or less than the predetermined time T _{_start} , that is, if T _off ≦T _{_start} (step S7: NO), the first dead band width setting unit 51 proceeds to step S3.

If it is determined in step S7 that the duration T _off of the hands-free state is longer than the predetermined time T _{_start} , that is, if it is determined that T _off >T _{_start} (step S7: YES), the first The dead zone width setting unit 51 determines whether or not the first dead zone width _W1 is smaller than the first dead zone width maximum value _{W1_max} (step S8). When the first dead zone width _W1 is smaller than the first dead zone width maximum value _{W1_max} (step S8: YES), the first dead zone width setting unit 51 sets the first dead zone width _W1 to the first dead zone width increase amount. The value obtained by adding _{W1_increase} is set as the first dead zone width _W1 (step S9). However, when the value obtained by adding the first dead band width increase amount _{W1_increase} to the first dead band width _W1 is larger than the first dead band width maximum value _{W1_max} , the first dead band width setting unit 51 sets the first dead band width The width maximum value _{W1_max} is set as the first dead zone width _W1 . Then, the first dead band width setting unit 51 ends the processing in the current calculation cycle.

If it is determined in step S8 that the first dead band width _W1 is greater than or equal to the first dead band width maximum value _{W1_max} (step S8: NO), the first dead band width setting unit 51 sets the first dead band width maximum The value _{W1_maxx} is set as the first dead zone width _W1 (step S10: NO). Then, the first dead band width setting unit 51 ends the processing in the current calculation cycle.

FIG. 10 is a graph showing an example of input/output characteristics of the first dead zone processing section 43. FIG.

A polygonal line L1 indicates the input/output characteristics of the first dead zone processing section 43 when the first dead zone width _W1 is set to the first dead zone width minimum value _{W1_min} . A polygonal line L2 indicates the input/output characteristics of the first dead zone processor 43 when the first dead zone width _W1 is set to the first dead zone width maximum value _{W1_max} .

Normally, the first dead zone width _W1 is set to the first dead zone width minimum value _{W1_min} . When the duration _Toff of the hands-free state is longer than the predetermined time _{T_start} , the first dead zone width _W1 is a value within the range of _{W1_min} < _W1 ≦ _{W1_max} .

FIG. 11 is a time chart showing an example of changes in the first dead zone width _W1 in the driving support mode.

In FIG. 11, it is assumed that the first dead zone width _W1 is set to the normal first dead zone width minimum value _{W1_min} at time t0. In the example of FIG. 11, from time t0 to time t1, the determination result of the hands-on/off determining unit 50 is the gripping state (gripping determination). From time t1 to time t4, the hands-on/off determination unit 50 determines that the hands are released (determined hands are released). After the time t4, the determination result of the hands-on/off determination unit 50 is the grasping state (holding determination).

During the period from time t0 to time t1, the determination result of the hands-on/off determination unit 50 is the grasping state (holding determination), so the first dead band width _W1 maintains the first dead band width minimum value _{W1_min} .

Even if the determination result of the hands-on/off determination unit 50 changes to the hands-free state (hands-free determination) at time t1, the first dead zone width _W1 remains the first dead zone width minimum value until the predetermined time _{T_start} elapses from time t1. Maintain W _{1_min} .

When the predetermined time _{T_start} has passed from time t1 (time t2), the first dead zone width _W1 increases. When the first dead band width _W1 reaches the first dead band width maximum value _{W1_max} (time t3), the first dead band width _W1 maintains the first dead band width maximum value _{W1_max} .

When the determination result of the hands-on/off determination unit 50 changes to the gripping state (gripping determination) at time t4, the first dead zone width _W1 decreases. When the first dead band width _W1 reaches the first dead band minimum width _{W1_min} (time t5), the first dead band width _W1 maintains the first dead band width minimum value _{W1_min} .

As shown in FIG. 11, the absolute value of the amount of change per unit time of the first dead band width _W1 when the first dead band width _W1 is increased (the absolute value of the slope of the graph between t2 and t3 in FIG. 11) To increase the absolute value of the amount of change per unit time of the first dead band width W ₁ (absolute value of the slope of the graph between t4 and t5 in FIG. 11) when the first dead band width W ₁ is reduced is preferred. That is, it is preferable to make the first dead band width decrease amount _{W1_decrease} larger than the first dead band width increase amount _{W1_increase} .

The reason for this is as follows. The increase in the first dead zone width _W1 is performed at the time of hands-free determination. Since the hands-off determination is more dubious than the gripping determination, it is preferable that the amount of change per unit time of the first dead zone width _W1 when the first dead zone width increases is relatively small. On the other hand, the first dead zone width _W1 is decreased during grip determination. Since the grip judgment is more accurate than the hands-free judgment, it is preferable to return the first dead zone width _W1 to the normal state as soon as possible when the first dead zone width decreases. However, the first dead zone width increase amount _{W1_increase} and the first dead zone width decrease amount _{W1_decrease} may be the same value.

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. However, in the second dead band width setting process, the first dead band width W ₁ , the first dead band minimum value W _{1 — min} , the first dead band width maximum value W _{1 — max} , the first dead band width decrease amount W _{1 —} decrease, and the first dead band width W 1 — The dead band width increase amount _{W1_increase} is the second dead band width _W2 , the second dead band width minimum value _{W2_min} , the second dead band width maximum value _{W2_max} , the second dead band width decrease amount _{W2_decrease} , and the second dead band width increase amount, respectively. W _{2_increase} .

When the operation mode is the normal mode, the first dead band width setting unit 51 sets the first dead band width minimum value _{W1_min} as the first dead band width _{W1_min} , and the second dead band width setting unit 52 sets the second dead band width W1_min. The dead zone width minimum value _{W2_min} is set as the second dead zone width _W2 . That is, in the normal mode, the first dead zone width _W1 and the second dead zone width _W2 are not changed.

In the above-described embodiment, in the driving support mode, the first dead zone width _W1 and the second dead zone width _W2 are increased when the hands-on/off determination unit 50 determines that the driver is in a hands-free state for a predetermined time or longer. be. When the first dead zone width _W1 and the second dead zone width _W2 are increased, the manual steering command values θ ^* _{c, md} with respect to the driver torque (driver input) are decreased. As a result, the amount of rotation of the output shaft 9 based on the driver torque is reduced, so that the torsion bar 10 is easily twisted even by a relatively small rotation of the steering wheel 2 by the driver's operation. As a result, the steering torque _Ttb and the driver torque increase, so that the accuracy of the hands-on/off determination by the hands-on/off determination unit 50 increases. As a result, it is possible to prevent or suppress an erroneous determination that the driver is not holding the steering wheel 2 even though the driver is gripping the steering wheel 2 when the driver torque input is small, such as when the vehicle is running straight.

[3] First Modification of Motor Control ECU 202 FIG. 12 is a block diagram for explaining the electrical configuration of a modification of the motor control ECU 202. As shown in FIG. In FIG. 12, the same reference numerals as in FIG. 2 are given to the parts corresponding to the parts in FIG. 2 described above.

In the first modified example, the configuration of the functional processing section in the microcomputer 40A is different from that in FIG. Specifically, in the first modification, instead of the first dead zone processor 43, the second dead zone processor 45, the first dead zone width setting part 51, and the second dead zone width setting part 52 of FIG. A processing unit 53 and a third dead band width setting unit 54 are provided.

The third dead zone processing section 53 is arranged upstream of both the assist torque command value setting section 44 and the manual steering command value generating section 46 . When the steering torque _Ttb is within the range of -W ₃ /2 or more and W ₃ /2 or less (third dead zone region), where W ₃ is the third dead zone width, the third dead zone processing unit 53: Zero is output as the steering torque Ttb _,de after the third dead zone processing.

In a region where the steering torque T _tb is smaller than −W ₃ /2, the third dead zone processing unit 53 sets [T _tb +(W ₃ /2)] as the steering torque T _tb,de after the third dead zone processing. Output. In a region where the steering torque T _tb is greater than W ₃ /2, the third dead zone processing unit 53 outputs [T _tb −(W ₃ /2)] as the steering torque T _tb,de after the third dead zone processing. do.

The third dead zone width _W3 is set by the third dead zone width setting section 54 . The third dead band width setting unit 54 sets the third dead band 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 in the driving support mode.

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 in FIG. However, in the third dead band width setting _process _, in _FIG _. The dead band width increase amount _{W1_increase} is the third dead band width _W3 , the third dead band width minimum value _{W3_min} , the third dead band width maximum value _{W3_max} , the third dead band width decrease amount _{W3_decrease} , and the third dead band width increase amount. W is replaced by _{3_increase} .

In the first modification, the assist torque command value setting unit 44 sets the assist torque command values T ^* _m,md based on the steering torque Ttb _,de and the vehicle speed V after the third dead zone processing. The manual steering command value generator 46 calculates a manual steering command value θ _*c,md based on the assist torque command value T ^* _m,md and the steering torque _Ttb,de after the third dead zone processing.

Specifically, the manual steering command value generation unit 46 substitutes the steering torque Ttb _,de after the third dead zone processing for Ttb, _de in Equation (2), and T ^* _m,md in Equation (2). _{, de} are substituted with the assist torque command values T ^* _{m and md} , and the differential equation of equation (2) is solved to calculate the rotation _angle _θc of the lower column. Set the angle θ as _c,md .

In the driving assistance mode, when the hands-on/off determination unit 50 determines that the driver is in a hands-free state for a predetermined period of time or longer, the third dead zone width _W3 is increased. Effects similar to those of the embodiment can be obtained.

When the operation mode is the normal mode, the third dead zone width setting unit 54 sets the third dead zone width minimum value _{W3_min} as the third dead zone width _W3 . That is, in the normal mode, the third dead band width _W3 is not changed.

[4] Second Modification of Motor Control ECU 202 FIG. 13 is a block diagram for explaining the electrical configuration of a modification of the motor control ECU 202. As shown in FIG.

The motor control ECU 202 includes a microcomputer 40B, a drive circuit (inverter circuit) 31 that is controlled by the microcomputer 40B, and a drive circuit (inverter circuit) 31 that supplies electric power to the electric motor 18 _{. int} ”).

The microcomputer 40B has a CPU and memory (ROM, RAM, non-volatile memory, etc.), and functions as a plurality of functional processing units by executing predetermined programs. The plurality of functional processing units include an assist control unit 111, an automatic steering control unit 112, an integrated torque calculation unit (integrated control amount calculation unit) 113, a torque control unit (control unit) 114, and an actual steering angle calculation unit. a fourth dead zone processor 116; a fifth dead zone processor 117; an actual automatic steering angle calculator 118; a hands-on/off determination module 119; a fourth dead zone width setting part 120; 121.

The assist control unit 111 sets an assist torque command value (assist control amount) T ^* _{m, md,} which is a target value of the assist torque required for manual steering. The assist control unit 111 sets assist torque command values T ^* _{m and md} based on the vehicle speed V and the steering torque _Ttb detected by the torque sensor 12 . The assist control unit 111 sets the assist torque command values T ^* _{m and md} in the same manner as the assist torque command value setting unit 44 in FIG.

The automatic steering control unit 112 uses an automatic steering angle command value θ ^* _c,ad given from the host ECU 201 and an actual automatic steering angle _θc,ad described later to determine an automatic steering torque command value (automatic steering torque command value) necessary for automatic steering. Steering control amount) T ^* _m,ad is set. Details of the automatic steering control unit 112 will be described later.

The integrated torque calculation unit 113 calculates an integrated torque command value (integrated control amount) T ^* _m, int by adding the automatic steering torque command value T ^* m _,ad to the assist torque command value T ^* _m,md. .

The torque control unit 114 drives the drive circuit 31 so that the motor torque of the electric motor 18 approaches the integrated torque command value T ^* _m,int . Since the configuration of the torque control section 114 is the same as the configuration of the torque control section 49 shown in FIG. 8, description thereof will be omitted.

The actual steering angle calculator 115 calculates the rotation angle θ _c,int of the output shaft 9 based on the output signal of the rotation angle sensor 23 . Specifically, the actual steering angle calculator 115 includes a rotation angle calculator 115A and a reduction ratio divider 115B. The rotation angle calculator 115A calculates the rotor rotation angle θ _m,int of the electric motor 18 based on the output signal of the rotation angle sensor 23 . The reduction ratio division unit 115B divides the rotor rotation angle θm _,int calculated by the rotation angle calculation unit 115A by the reduction ratio N of the speed reducer 19, thereby dividing the rotor rotation angle θm _,int into the rotation of the output shaft 9. The angle (actual steering angle) θ is converted to _c,int .

The actual steering angle θc _,int is the steering angle for manual steering (hereinafter referred to as “actual manual steering angle _θc,md ”) based on the steering torque _Ttb and the assist torque command value T ^* _m,md , and the automatic steering angle θc,md. and a steering angle for automatic steering based on the steering torque command value T ^* _m,ad (hereinafter referred to as "actual automatic steering angle _θc,ad ").

The steering torque _Ttb is input to the fourth dead zone processing unit 116 . If the width of the fourth dead band is _W4 , and the steering torque _Ttb is within the range of _-W4 /2 or more and _W4 /2 or less (fourth dead band region), the fourth dead band processing unit 116: Zero is output as the steering torque Ttb _,de after the fourth dead zone processing.

In a region where the steering torque T _tb is smaller than −W ₄ /2, the fourth dead zone processing unit 116 sets [T _tb +(W ₄ /2)] as the steering torque T _tb,de after the fourth dead zone processing. Output. In a region where the steering torque T _tb is greater than W ₄ /2, the fourth dead zone processing unit 116 outputs [T _tb −(W ₄ /2)] as the steering torque T _tb,de after the fourth dead zone processing. do. The fourth dead band width _W4 is set by the fourth dead band width setting section 120 .

The assist torque command values T ^* _{m, md} are input to the fifth dead zone processing unit 117 . Assuming that the width of the fifth dead band is _W5 , the fifth dead band processing unit 11 sets the assist torque command value T ^* _{m, md} within a range of _-W5 /2 or more and _W5 /2 or less (fifth dead band region). In some cases, zero is output as the assist torque command value T ^* _m,md,de after the fifth dead zone processing.

In a region where the assist torque command values T ^* _{m, md} are smaller than -W ₅ /2, the fifth dead zone processing unit 11 calculates [T ^* _{m, md} + (W ₅ /2)] after the fifth dead zone processing. are output as assist torque command values T ^* _{m, md, and de} . In a region where the assist torque command values T ^* _{m, md} are greater than W ₅ /2, the fifth dead zone processing unit 11 converts [T ^* _{m, md} - (W ₅ /2)] to They are output as assist torque command values T ^* _{m, md, and de} . The fifth dead band width _W5 is set by the fifth dead band width setting section 121 .

The actual automatic steering angle calculator 118 calculates the actual automatic steering angle θc _,ad included in the actual steering angle θc _,int . Specifically, the actual automatic steering angle calculator 118 includes an actual manual steering angle calculator 118A and a subtractor 118B. The actual manual steering angle calculator 118A calculates the actual manual steering angle θc based on the steering torque Ttb _,de after the fourth dead band processing and the assist torque command value T ^* _{m, md, de} after the fifth dead band processing _{. , md} . The subtraction unit 118B subtracts the actual manual steering angle θc,md calculated by the actual manual steering angle calculation unit 118A from the actual steering angle θc _,int calculated by the actual steering angle calculation unit 115, thereby obtaining the actual automatic steering angle θc, _md . A steering angle θc _,ad is calculated. This actual automatic steering angle θ _c,ad is given to the automatic steering control section 112 .

In this embodiment, the actual manual steering angle calculator 118A uses a reference model (reference EPS model) of the electric power steering system 1 to calculate the actual manual steering angles _θc,md .

The actual manual steering angle calculator 118A calculates the actual manual steering angle _θc,md using, for example, the reference EPS model shown in FIG.

Referring to FIG. 4, the road load torque _Trl is expressed by the above equation (1) using the spring constant k and the viscous damping coefficient c. Also in this modification, the spring constant k and the viscous damping coefficient c are set in advance.

The equation of motion of the reference EPS model in FIG. 4 is represented by the above-described equation (2). The actual manual steering angle calculation unit 118A substitutes the steering torque Ttb _,de after the fourth dead zone processing for Ttb,de in Equation (2), and substitutes T ^* _m,md,de for T* _m,md,de in Equation (2) with the fifth By substituting the assist torque command values T ^* _{m, md, and de} after the dead zone processing and solving the differential equation of formula (2), the rotation angle _θc of the lower column is calculated, and the obtained rotation angle _θc is calculated as It is set as the actual manual steering angle θc _,md .

The hands-on/off determination unit 119 determines whether the user is in a gripping state or in a hands-free state by the same method as the hands-on/off determination unit 50 in FIG.

The fourth dead band width setting unit 120 and the fifth dead band width setting unit 121 respectively set the fourth dead band width _W4 and the fifth dead band width W based on the hands-on/off determination result of the hands-on/off determination unit 119 during the driving assistance mode. Set ₅ . The operations of the fourth dead band width setting section 120 and the fifth dead band width setting section 121 will be described later.

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

FIG. 14 is a block diagram showing the configuration of the automatic steering control section 112. As shown in FIG.

The automatic steering control unit 112 calculates an automatic steering torque command value T ^* _m ,ad using the automatic steering angle command value θ ^* _c,ad and the actual automatic steering angle _θc,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 A division unit 167 and a reduction ratio multiplication unit 168 are included.

A reduction ratio multiplication unit 168 multiplies the automatic steering torque command value T ^* _m,ad calculated by the reduction ratio division unit 167 by the reduction ratio N of the reduction gear 19, thereby obtaining the automatic steering torque command value T ^* _m,ad. is converted into an automatic output shaft torque command value N·T ^* _m,ad (=T ^* _c,ad ) acting on the output shaft 9 (worm wheel 21).

A low-pass filter 161 performs low-pass filter processing on the automatic steering angle command value θ ^* _c,ad . The automatic steering angle command value θ ^* _{c, adf} after low-pass filtering is provided to feedback control section 162 and feedforward control section 163 .

The feedback control unit 162 brings the actual automatic steering angle _θc,ad calculated by the actual automatic steering angle calculation unit 118 (see FIG. 13) closer to the automatic steering angle command value θ ^* _c,adf after low-pass filtering. is provided in Feedback control section 162 includes an angular deviation calculation section 162A and a PD control section 162B. The angle deviation calculator 162A calculates a deviation Δθ _c,ad (=θ ^* _c,adfd −θ _c,ad ₎ between the automatic steering angle command value θ ^* _c,adf and the actual automatic steering angle θc,ad. The _angle deviation calculation unit 162A calculates the deviation (θ ^* _c ^, _adfd −^θ _c,ad ) may be calculated as the angular deviation Δθ _c,ad .

The PD control section 162B calculates the feedback control torque T _fb _{,ad by performing PD calculation (proportional differential calculation) on the angular deviation Δθ c,} ad calculated by the angular deviation calculating section 162A. The feedback control torque T _fb,ad is applied to the torque adder 165 .

The feedforward control unit 163 is provided to compensate for the response delay due to the inertia of the electric power steering system 1 and improve the control response. Feedforward control section 163 includes an angular acceleration calculation section 163A and an inertia multiplication section 163B. The angular acceleration calculator 163A calculates a target angular acceleration ^d2θ ^* _c, adf/ ^dt2 by second-order differentiating the automatic steering angle command value θ ^* _c,adf .

The inertia multiplier 163B multiplies the target angular acceleration d ² θ ^* _{c, adf} /dt ² calculated by the angular acceleration calculator 163A 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 is obtained, for example, from a physical model (see FIG. 15) of the electric power steering system 1, which will be described later. The feedforward control torque Tff _,ad is given to the torque adder 165 as an inertia compensation value.

The torque adder 165 calculates a basic torque command value (T _fb,ad +T _ff, _ad ) by adding the feedforward control torque T _ff,ad to the feedback control torque T fb,ad .

The _disturbance torque estimating unit 164 _{mainly calculates an} automatic disturbance torque estimation value ^ It is provided to compute Tlc _,ad . The disturbance torque T _lc,ad for the automatic steering is the torque for the object (plant) to be driven by the electric motor 18, assuming that only the automatic steering control based on the automatic steering torque command value T ^* _m,ad is performed. Refers to torque other than motor torque that is generated as a disturbance.

Assuming that only the automatic steering control based on the automatic steering torque command value T ^* _m,ad 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 output of the plant becomes the actual automatic steering angle _θc,ad . Therefore ^, the _disturbance torque ^estimator ₁₆₄ calculates the automatic disturbance torque T _lc _{, ad} , the actual automatic steering angle _θc,ad , and the differential value (actual automatic angular velocity) _dθc _,ad /dt of the actual automatic steering angle θc,ad. In the following we denote the estimated values of T _lc,ad , θ _c,ad and dθ _c,ad /dt by ̂T _lc,ad , ̂θ _c,ad and ̂dθ _c,ad /dt, respectively. The details of the disturbance torque estimator 164 will be described later.

The automatic disturbance torque estimation value _̂Tlc,ad calculated by the disturbance torque estimator 164 is given to the disturbance torque compensator 166 as an automatic disturbance torque compensation value.

The disturbance torque compensator 166 subtracts the automatic disturbance torque estimation value ̂T _lc,ad from the basic torque command value (T _fb,ad +Tff _,ad ) to obtain the automatic output shaft torque command value T ^* _c,ad ( =T _fb,ad +T _ff,ad −̂T _lc,ad ). As a result, the automatic output shaft torque command value T ^* _c,ad (target torque for the output shaft 9) in which the automatic disturbance torque is compensated is obtained.

The automatic output shaft torque command value T ^* _c,ad is given to the reduction ratio dividing section 167 . A reduction ratio division unit 167 divides the automatic output shaft torque command value T ^* _c,ad by the reduction ratio N to calculate an automatic steering torque command value T ^* _m,ad (target torque for the electric motor 18). This automatic steering torque command value T ^* _m,ad is given to the integrated torque calculator 113 (see FIG. 13).

The disturbance torque estimator 164 will be described in detail. The disturbance torque estimator 164 uses, for example, the physical model 101A _of the electric power steering system 1 shown in FIG _. It consists of a disturbance observer that calculates the actual automatic angular velocity estimate ̂dθ _c,ad /dt. However, FIG. 15 shows a physical model assuming that only the automatic steering control based on the automatic steering torque command value T ^* _m,ad is performed.

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 is provided with a steering torque (torsion bar torque) _Ttb , which is a twisting torque of the torsion bar 10, and is provided with a road load torque _Trl,ad from the steered wheels 3 side. Further, the plant 102A is given an automatic output shaft torque command value N·T ^* _m,ad from the motor via the worm gear 20, and the friction between the worm wheel 21 and the worm gear 20 produces a friction torque _Tf,ad. is given.

Assuming that 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).

d ² θ _c,ad /dt ² is the angular acceleration of plant 102A. N is the speed reduction ratio of the speed reducer 19 . _Tlc,ad indicates the automatic disturbance torque applied to the plant 102A. In this embodiment, the automatic disturbance torque Tlc _,ad is shown as the sum of the steering torque _Ttb , the road load torque _Trl,ad, and the friction torque _Tf,ad . Tlc _,ad includes other torques.

The state equation for the physical model 101A of FIG. 15 is expressed by the following equation (11).

(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 equation (11), A is the system matrix, B1 is the first input matrix, B2 is the second input matrix, C is the output matrix, and D is the feedthrough matrix.

We extend the above state equation to a system that includes the unknown input vector _u2 as one of the states. The state equation of the extended system (extended state equation) is represented by the following equation (12).

In the above equation (12), x _e is the state variable vector of the extended system and is expressed by the following equation (13).

In the above equation (12), A _e is the system matrix of the extended system, B _e is the known input matrix of the extended system, and C _e is the output matrix of the extended system.

A disturbance observer (extended state observer) represented by the following equation (14) is constructed from the extended state equation of equation (12) above.

In equation (14), ̂x _e represents an estimate of x _e . Also, L is an observer gain. Also, ^y represents the estimated value of y. ^x _e is represented by the following equation (15).

In equation (15), ^θc _,ad is the estimated value of the actual automatic steering angle _θc,ad , ^dθc _,ad /dt is the estimated value of the angular velocity _dθc,ad /dt, and ^ _{Tlc , ad} is the estimated value of the automatic disturbance torque Tlc _,ad .

The disturbance torque estimator 164 calculates the state variable vector ̂x _e based on the equation (14).

FIG. 16 is a block diagram showing the configuration of the disturbance torque estimator 164. As shown in FIG.

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 It includes an addition section 187 , an integration section 188 and a state variable vector output section 189 .

The automatic output shaft torque command value N·T ^* _m,ad (=T ^* _c,ad ) calculated by the reduction ratio multiplication section 168 (see FIG. 14) is given to the input vector input section 181 . The input vector input unit 181 outputs an input vector _u1 .

The output of the integrator 188 is the state variable vector ̂x _e (see equation (15) above). At the start of computation, an initial value is given as the state variable vector _̂xe . The initial value of the state variable vector ̂x _e is 0, for example.

A system matrix multiplier 186 multiplies the state variable vector ̂x _e by the system matrix A _e . The output matrix multiplier 182 multiplies the state variable vector ̂x _e by the output matrix C _e .

The first adder 183 subtracts the output (C _e ·̂x _e ) of the output matrix multiplier 182 from the output vector y, which is the actual automatic steering angle θ _c,ad . That is, the first adder 183 calculates the difference (y−̂y) between the output vector y and the output vector estimate value ̂y (=C _e ·̂x _e ). The gain multiplier 184 multiplies the output (y−̂y) of the first adder 183 by the observer gain L (see formula (14) above).

The input matrix multiplication unit 185 multiplies the input vector u1 output from the input vector input unit ₁₈₁ by the input matrix _Be . The second adder 187 outputs the input matrix multiplier 185 output (B _e ·u ₁ ), the system matrix multiplier 186 output (A _e ·̂x _e ), and the gain multiplier 184 output (L(y −^y)) is added to calculate the differential value d^x _e /dt of the state variable vector. The integrator 188 calculates the state variable vector ̂x _e by integrating the output (d̂x _e /dt) of the second adder 187 . A state variable vector output unit ₁₈₉ outputs an automatic disturbance torque estimation value _̂Tlc,ad , an actual automatic steering angle estimation value ̂θc _,ad, and an actual automatic angular velocity estimation value d̂θc based on the state variable vector _{̂xe. , ad} /dt.

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

Therefore, the inverse model of the plant is the following formula (16).

Inputs to the disturbance observer using the inverse model of the plant are J·d ² θ _c,ad /dt ² and N·T ^* _m,ad _. , is greatly affected by noise from the rotation angle sensor 23 . On the other hand, the extended state observer described above estimates the disturbance torque in an integral manner, and therefore has the advantage of being able to reduce the noise effect due to differentiation.

Next, operations of the fourth dead band width setting section 120 and the fifth dead band width setting section 121 will be described. The fourth dead band width setting unit 120 performs a fourth dead band width setting process for setting the fourth dead band width _W4 in the driving assistance mode. The fifth dead band width setting unit 121 performs a fifth dead band width setting process for setting the fifth dead band width _W5 in the driving assistance mode.

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. However, in the fourth dead band width setting process, the first dead band width _W1 , the first dead band minimum value _{W1_min} , the first dead band maximum value _{W1_max} , the first dead band width decrease amount _{W1_decrease} and the first dead band width W1_min shown in FIG. The dead band width increase amount _{W1_increase} is the fourth dead band width _W4 , the fourth dead band width minimum value _{W4_min} , the fourth dead band width maximum value _{W4_max} , the fourth dead band width decrease amount _{W4_decrease} , and the fourth dead band width increase amount. W is replaced by _{4_increase} .

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. However, in the fifth dead band width setting process, the first dead band width W ₁ , the first dead band minimum value W _{1 — min} , the first dead band width maximum value W _{1 — max} , the first dead band width decrease amount W _{1 —} decrease, and the first dead band width W 1 — The dead band width increase _{W1_increase} is the fifth dead band width _W5 , the fifth dead band width minimum value _{W5_min} , the fifth dead band width maximum value _{W5_max} , the fifth dead band width decrease _{W5_decrease} , and the fifth dead band width increase. W is replaced by _{5_increase} .

In the second modification, the integrated torque command value is the sum of the automatic steering torque command value T ^* m, _ad calculated based on the feedback control torque Tfb _,ad and the assist torque command value T ^* _m,md. The electric motor 18 is driven based on T ^* _m,int . Therefore, in the driving support mode, the output shaft 9 is normally rotated based on the automatic steering torque command value T ^* _m,ad , and the steering torque _Ttb and the assist torque command value generated based on the driver torque. The output shaft 9 is rotated based on T ^* _m,md .

The fourth dead zone width _W4 and the fifth dead zone width _W5 are increased when the hands-on/off determining unit 119 continues to determine that the vehicle is in a hands-free state for a predetermined time or longer in the driving support mode. When the fourth dead band width _W4 and the fifth dead band width _W5 are increased, the absolute value of the actual manual steering angle θ _c,md with respect to the driver torque, that is, the angle at which the driver is permitted to steer for driving assistance. is smaller than normal.

As a result, the value of the actual automatic steering angle θc _,ad used for feedback control becomes larger than the normal value, and the motor is driven through the feedback control torque Tfb _,ad and the automatic steering torque command value T ^* _m,ad in order. Reflected in the torque command value.

As a result, the amount of rotation of the output shaft 9 based on the driver torque is reduced, as in the embodiment of FIG. As a result, even if the steering wheel 2 is rotated, the rotation is less likely to be transmitted, and the torsion bar 10 is more likely to be twisted. As a result, the steering torque _Ttb and the driver torque increase, so that the accuracy of the hands-on/off determination by the hands-on/off determination unit 119 increases. As a result, it is possible to prevent or suppress an erroneous determination that the driver is not holding the steering wheel 2 even though the driver is gripping the steering wheel 2 when the driver torque input is small, such as when the vehicle is running straight.

In the second modification, in the normal mode, assist torque command value T ^* _m,md set by assist control unit 111 is given to torque control unit 114 as integrated torque command value T ^* _m,int . Therefore, in the normal mode, drive circuit 31 is driven based only on assist torque command values T ^* _{m, md} .

[4] Third Modification of Motor Control ECU 202 FIG. 17 is a block diagram for explaining the electrical configuration of a third modification of the motor control ECU 202. As shown in FIG. In FIG. 17, the same reference numerals as in FIG. 13 denote the parts corresponding to the parts in FIG. 13 described above.

In the third modified example, the configuration of the functional processing section in the microcomputer 40C is different from that in FIG. Specifically, in the third modification, instead of the fourth dead zone processing section 116, the fifth dead zone processing section 117, the fourth dead zone width setting section 120, and the fifth dead zone width setting section 121 of FIG. A processing unit 123 and a sixth dead band width setting unit 124 are provided.

The sixth dead zone processing section 123 is arranged in the front stage of both the assist control section 111 and the actual manual steering angle calculation section 118A. If the width of the sixth dead band is _W6 , and the steering torque _Ttb is within the range of _-W6 /2 or more and _W6 /2 or less (sixth dead band region), the sixth dead band processing unit 123: Zero is output as the steering torque Ttb _,de after the sixth dead zone processing.

In a region where the steering torque T _tb is smaller than −W ₆ /2, the sixth dead zone processing unit 123 sets [T _tb +(W ₆ /2)] as the steering torque T _tb,de after the sixth dead zone processing. Output. In a region where the steering torque T _tb is greater than W ₆ /2, the sixth dead zone processing unit 123 outputs [T _tb −(W ₆ /2)] as the steering torque T _tb,de after the sixth dead zone processing. do.

The sixth dead zone width _W6 is set by the sixth dead zone width setting section 124 . The sixth dead band width setting unit 124 sets the sixth dead band 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 in the driving assistance mode.

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. However, in the sixth dead band width setting process, the first dead band width W ₁ , the first dead band width minimum value W _{1 — min} , the first dead band width maximum value W _{1 — max} , the first dead band width decrease amount W _{1 —} decrease, and the first dead band width W 1 — The dead band width increase _{W1_increase} is the sixth dead band width _W6 , the sixth dead band width minimum value _{W6_min} , the sixth dead band width maximum value _{W6_max} , the third dead band width decrease _{W6_decrease} , and the sixth dead band width increase. W _{6_increase} .

In the third modification, the assist control unit 111 sets the assist torque command values T ^* _m,md based on the steering torque Ttb _,de and the vehicle speed V after the sixth dead zone processing. The actual manual steering angle calculation unit 118A calculates the actual manual steering angle _θc,md based on the assist torque command value T ^* _m,md and the steering torque Ttb _,de after the sixth dead zone processing.

Specifically, the actual manual steering angle calculation unit 118A substitutes the steering torque _Ttb,de after the sixth dead zone processing for Ttb, _de in the equation (2), and calculates T ^* _m,md in the equation (2). _{, de} are substituted with the assist torque command values T ^* _{m and md} , and the differential equation of equation (2) is solved to calculate the rotation _angle _θc of the lower column. Set the angle θ as _c,md .

In the driving support mode, when the hands-on/off determining unit 119 continues to determine that the driver is in a hands-free state for a predetermined period of time or more, the sixth dead zone width _W6 is increased. An effect similar to that of the second modification can be obtained.

In the third modification, in the normal mode, assist torque command value T ^* _m,md set by assist control unit 111 is given to torque control unit 114 as integrated torque command value T ^* _m,int . Therefore, in the normal mode, drive circuit 31 is driven based only on assist torque command values T ^* _{m, md} .

In the above-described embodiment, as shown in FIG. 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 Although the control is based on the OFF determination result, only one of the first dead zone width _W1 and the second dead zone width _W2 may be controlled based on the hands-on/off determination result. Alternatively, only one of the first dead zone processor 43 and the second dead zone processor 45 may be provided, and the dead zone used by the dead zone processor may be controlled based on the hands-on/off determination result.

In the second modification described above, as shown in FIG. 13, both the fourth dead zone width _W4 used in the fourth dead zone processing section 116 and the fifth dead zone width _W5 used in the fifth dead zone processing section 117 are , are controlled based on the hands-on/off determination result, but only one of the fourth dead zone width _W4 and the fifth dead zone width _W5 may be controlled based on the hands-on/off determination result. Alternatively, only one of the fourth dead zone processing section 116 and the fifth dead zone processing section 117 may be provided, and the dead zone used by the dead zone processing section may be controlled based on the hands-on/off determination result.

In the above-described embodiment, an example in which the present invention is applied to column-type EPS motor control has been shown, but the present invention can also be applied to motor control of EPSs other than column-type EPS.

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

REFERENCE SIGNS LIST 1 electric power steering device 3 steered wheels 4 steering mechanism 18 electric motor 43 first dead zone processing section 44 assist torque command value setting section 45 second dead zone processing section 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 band width setting unit 52 Second dead band width Setting unit 53 Third dead band width processing unit 54 Third dead band 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 part 119...Hands-on/off determination part 120...Fourth dead zone width setting part 121...Fifth dead zone width setting part 122...Sixth dead zone width processing part 123...Sixth dead zone width setting part 201...

Upper ECUs

201, 202 ... ECU for motor control

Claims

a torque detector for detecting 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 generation unit that generates a manual steering command value using the steering torque and the assist torque command value;
an integrated angle command value calculation unit that calculates an integrated angle command value by adding the manual steering command value to the automatic steering command value given in the driving assistance mode;
a control unit that performs angle control 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 gripping the steering wheel or is in a hands-free state where the driver is not gripping the steering wheel;
at least one of the steering torque input to the manual steering command value generation section, the assist torque command value input to the manual steering command value generation section, and the steering torque input to the assist torque command value calculation section; a provided dead zone processing unit;
Dead zone width setting for changing the dead zone width of at least one of the dead zone processors when the hands-on/off determination part determines that the hands are released for a predetermined time or more during the driving support mode. and a motor control device.
A torque detection unit for detecting steering torque, a steering angle detection unit for detecting actual steering angle, and an automatic steering control unit for setting an automatic steering control amount based on an automatic steering command value given in the driving assistance mode. an assist control unit that sets an assist control amount using the steering torque; an integrated control amount calculation unit that calculates an integrated control amount by adding the automatic steering control amount and the assist control amount; A motor control device including a control unit that controls 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 gripping the steering wheel or is in a hands-free state where the driver is not gripping the steering wheel;
an actual manual steering angle calculation unit that calculates an actual manual steering angle that is a steering angle corresponding to 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 corresponding to 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 zone provided in at least one of the steering torque input to the actual manual steering angle calculation section, the assist control amount input to the actual manual steering angle calculation section, and the steering torque input to the assist control section. a processing unit;
Dead zone width setting for changing the dead zone width of at least one of the dead zone processors when the hands-on/off determination part determines that the hands are released for a predetermined time or more during the driving support mode. and a motor controller.
Assuming that the dead band processing unit whose dead band width is changed by the dead band width setting unit is a dead band processing unit with a variable dead band width,
The dead zone width setting part increases the dead zone width of the dead zone processing part with a variable dead zone width when the hands-on/off determination part determines that the hand is released for a predetermined time or longer in the driving support mode. 3. A motor controller according to claim 1 or 2, configured to:
In the driving support mode, when the hands-on/off determining unit continues to make a determination that the hands are released for a predetermined period of time, the dead band width setting unit continues to determine that the hands are released from that time point. 4. The motor control device according to claim 3, wherein said dead band width is gradually increased while said dead band width is on, and when said dead band width reaches a predetermined upper limit value, said dead band width is held at said upper limit value.
In the driving assistance mode, the dead band width setting unit determines that the hands-on/off determination unit determines that the hands-on/off state has changed to the gripping state after a determination result of the hands-on/off determination unit that the hands are released is continued for a predetermined time or longer. Sometimes, the width of the dead zone is gradually decreased while the determination result indicating that the gripping state continues from that time point, and when the width of the dead zone reaches a predetermined lower limit, the width of the dead zone is reduced to the lower limit. 5. The motor controller of claim 4, holding.