Motor control device

Abstract

To provide a motor control device which can perform adequate cooperative control according to operation mode.SOLUTION: A motor control device includes: a manual steering command value generation part which generates a manual steering command value by use of a steering torque and an assist torque command value; an integrated angle command value calculation part which calculates an integrated angle command value by adding the manual steering command value to an automatic steering command value; a control part which controls an angle of an electric motor for steering angle control on the basis of the integrated angle command value; a dead zone treatment part which is provided on at least one of the steering torque inputted to the manual steering command value generation part, the assist torque command value inputted to the manual steering command value generation part, and the steering torque inputted to an assist torque command value calculation part; and a dead zone width changing part which changes a dead zone width of at least one dead zone treatment part.SELECTED DRAWING: Figure 2

Description

[Technical Field]

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

[0002] The following Patent Document 1 discloses a motor control device that includes a manual steering command value calculation unit that calculates a manual steering command value using steering torque, 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, and a control unit that controls the angle of an electric motor based on the integrated angle command value.

[0003] In the motor control device described in Patent Document 1, when the driving mode is automatic driving mode, the electric motor is controlled based on an integrated angle command value obtained by adding a manual steering command value to an automatic steering command value. This allows cooperative control that allows manual steering while performing steering control mainly based on automatic steering control, without switching between manual steering control and automatic steering control. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 2019-194059 Summary of the Invention [Problem to be solved by the invention]

[0005] An object of one embodiment of the present invention is to provide a motor control device that can perform appropriate cooperative control depending on the operation mode. [Means for solving the problem]

[0006] One embodiment of the present invention includes a torque detection unit for detecting steering torque, an assist torque command value setting unit for setting an assist torque command value using the steering torque, a manual steering command value generation unit for generating a manual steering command value using the steering torque and the assist torque command value, an integrated angle command value calculation unit for calculating an integrated angle command value by adding the manual steering command value to an automatic steering command value, a control unit for controlling the angle of an electric motor for steering angle control based on the integrated angle command value, and a control unit for controlling the steering torque to be input to the manual steering command value generation unit, the assist torque command value to be input to the manual steering command value generation unit, and the assist torque command value to be input to the manual steering command value generation unit. setting a dead zone processing unit provided for at least one of the steering torques input to a unit, and a dead zone width setting unit that sets the dead zone width of at least one of the dead zone processing units in accordance with a driving mode.

[0007] This configuration allows for appropriate cooperative control depending on the operating mode.

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

[0009] [Figure 1] FIG. 1 is a schematic diagram showing the general configuration of an electric power steering system to which a motor control device according to one embodiment of the present invention is applied. [Figure 2] FIG. 2 is a block diagram illustrating the electrical configuration of the motor control ECU. [Figure 3] FIG. 3 is a graph showing an example of setting the assist torque command value T* m,ad relative to the steering torque Ttb. [Figure 4] FIG. 4 is a schematic diagram showing an example of a reference EPS model used in the manual steering command value setting unit. [Figure 5] FIG. 5 is a block diagram showing the configuration of the angle control unit. [Figure 6]FIG. 6 is a schematic diagram showing an example of the configuration of a physical model of an electric power steering system. [Figure 7] FIG. 7 is a block diagram showing the configuration of the disturbance torque estimating unit. [Figure 8] FIG. 8 is a schematic diagram showing the configuration of the torque control unit. [Figure 9] FIG. 9 is a flowchart showing the procedure of a first dead-band width setting process performed by a first dead-band width setting unit. [Figure 10] FIG. 10 is a graph showing a specific example of the input / output characteristics of the first dead-band width setting unit. [Figure 11] FIG. 11 is a graph showing an example of setting the first dead-band width W1_lane with respect to the vehicle speed V by the first dead-band width setting unit. [Figure 12] FIG. 12 is a block diagram for explaining the electrical configuration of a modified example of the motor control ECU. DETAILED DESCRIPTION OF THE INVENTION

[0010] [Description of the embodiment of the present invention] One embodiment of the present invention includes a torque detection unit for detecting steering torque, an assist torque command value setting unit for setting an assist torque command value using the steering torque, a manual steering command value generation unit for generating a manual steering command value using the steering torque and the assist torque command value, an integrated angle command value calculation unit for calculating an integrated angle command value by adding the manual steering command value to an automatic steering command value, a control unit for controlling the angle of an electric motor for steering angle control based on the integrated angle command value, and a control unit for controlling the steering torque to be input to the manual steering command value generation unit, the assist torque command value to be input to the manual steering command value generation unit, and the assist torque command value to be input to the manual steering command value generation unit. setting a dead zone processing unit provided for at least one of the steering torques input to a unit, and a dead zone width setting unit that sets the dead zone width of at least one of the dead zone processing units in accordance with a driving mode.

[0011] This configuration allows for appropriate cooperative control depending on the operating mode.

[0012] In one embodiment of the present invention, the vehicle speed detection unit that detects the vehicle speed is further included, and the dead zone width setting unit is configured to set the dead zone width of the dead zone processing unit in consideration of the vehicle speed.

[0013] In one embodiment of the present invention, the driving modes include a lane keeping assist mode that prevents the vehicle from deviating from its lane; With other vehicles and an automatic parking mode for automatically parking the vehicle.

[0014] Detailed Description of the Embodiments of the Invention Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

[0015] [1] Overview of electric power steering system FIG. 1 is a schematic diagram showing the general configuration of an electric power steering system to which a motor control device according to one embodiment of the present invention is applied.

[0016] The electric power steering system 1 includes a steering wheel (handle) 2 as a steering member for steering the vehicle, a steering mechanism 4 that steers steered wheels 3 in conjunction with the rotation of the steering wheel 2, and a steering assist mechanism 5 that assists the driver in steering. The steering wheel 2 and the steering mechanism 4 are mechanically connected via a steering shaft 6 and an intermediate shaft 7.

[0017] The steering shaft 6 includes an input shaft 8 connected to the steering wheel 2 and an output shaft 9 connected to the intermediate shaft 7. The input shaft 8 and the output shaft 9 are connected via a torsion bar 10 so as to be capable of relative rotation.

[0018] A torque sensor (torque detection unit) 12 is disposed near the torsion bar 10. The torque sensor 12 detects the steering torque (torsion bar torque) T applied to the steering wheel 2 based on the amount of relative rotational displacement between the input shaft 8 and the output shaft 9. tb In this embodiment, the steering torque T tb For example, the torque for steering left is detected as a positive value, and the torque for steering right is detected as a negative value. The larger the absolute value of the torque, the greater the steering torque T tb The magnitude of is assumed to be large.

[0019] The steering mechanism 4 is made up of a rack-and-pinion mechanism including a pinion shaft 13 and a rack shaft 14 as a steering shaft. The steered wheels 3 are connected to each end of the rack shaft 14 via tie rods 15 and knuckle arms (not shown). The pinion shaft 13 is connected to the intermediate shaft 7. The pinion shaft 13 rotates in conjunction with the steering of the steering wheel 2. A pinion 16 is connected to the tip of the pinion shaft 13.

[0020] The rack shaft 14 extends linearly in the left-right direction of the vehicle. A rack 17 that meshes with the pinion 16 is formed in the middle of the rack shaft 14 in the axial direction. The pinion 16 and the rack 17 convert the rotation of the pinion shaft 13 into axial movement of the rack shaft 14. By moving the rack shaft 14 in the axial direction, the steered wheels 3 can be steered.

[0021] When the steering wheel 2 is steered (rotated), this rotation is transmitted to the pinion shaft 13 via the steering shaft 6 and the intermediate shaft 7. The rotation of the pinion shaft 13 is then converted into axial movement of the rack shaft 14 by the pinion 16 and the rack 17. As a result, the steered wheels 3 are steered.

[0022] The steering assist mechanism 5 includes an electric motor 18 for generating a steering assist force (assist torque), and a reducer 19 for amplifying the output torque of the electric motor 18 and transmitting it to the steering mechanism 4. The reducer 19 is made up of a worm gear mechanism including a worm gear 20 and a worm wheel 21 that meshes with the worm gear 20. The reducer 19 is housed in a gear housing 22 that serves as a transmission mechanism housing. In the following, the reduction ratio (gear ratio) of the reducer 19 may be represented by N. The reduction ratio N is determined by the rotation angle θ of the worm wheel 21. ww The rotation angle θ of the worm gear 20 relative to wg The ratio θ wg / θ ww is defined as:

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

[0024] When the worm gear 20 is rotationally driven by the electric motor 18, the worm wheel 21 is rotationally driven, and motor torque is applied to the steering shaft 6, causing the steering shaft 6 (output shaft 9) to rotate. The rotation of the steering shaft 6 is then transmitted to the pinion shaft 13 via the intermediate shaft 7. The rotation of the pinion shaft 13 is converted into axial movement of the rack shaft 14, thereby turning the steered wheels 3. In other words, by rotating the worm gear 20 with the electric motor 18, steering assistance by the electric motor 18 and steering of the steered wheels 3 become possible. The electric motor 18 is provided with a rotation angle sensor 23 for detecting the rotation angle of the rotor of the electric motor 18.

[0025] The torque applied to the output shaft 9 (an example of a drive target of the electric motor 18) includes motor torque from the electric motor 18 and disturbance torque other than the motor torque. Disturbance torque T lc The steering torque T tb , road load torque (road reaction torque) T rl , friction torque T f etc. are included.

[0026] Steering torque T tb is the torque applied to the output shaft 9 from the steering wheel 2 side by the force applied to the steering wheel 2 by the driver (driver torque) and the force generated by steering inertia.

[0027] Road load torque T rl is the torque applied to the output shaft 9 from the steered wheels 3 via the rack shaft 14 due to the self-aligning torque generated in the tires, forces generated by the suspension and tire-wheel alignment, frictional forces of the rack-and-pinion mechanism, etc.

[0028] The vehicle is equipped with a CCD (Charge Coupled Device) camera 25 that photographs the road ahead in the direction of travel of the vehicle, a GPS (Global Positioning System) 26 for detecting the vehicle's position, a radar 27 for detecting road shapes and obstacles, a map information memory 28 that stores map information, and a vehicle speed sensor (vehicle speed detection unit) 29 for detecting vehicle speed V.

[0029] The CCD camera 25, GPS 26, radar 27, map information memory 28, and vehicle speed sensor 29 are connected to a host ECU (Electronic Control Unit) 201 for performing automatic driving control (including driving assistance control). Based on the information obtained by the CCD camera 25, GPS 26, radar 27, and vehicle speed sensor 29 and map information, the host ECU 201 performs surrounding environment recognition, vehicle position estimation, route planning, etc., and determines control target values ​​for steering and drive actuators.

[0030] In this embodiment, the driving modes include a normal mode, a lane keeping assist mode, an automatic emergency avoidance mode, and an automatic parking mode. The normal mode is set by adjusting the manual steering command value θ * c,md or assist torque command value T * m,mdThe lane keeping assist mode is a mode in which steering is performed based on the vehicle's lane direction. The lane keeping assist mode is a mode in which driving assistance is performed to prevent the vehicle from deviating from its lane. For example, lane keep assist (LKA) is an example of an application that is executed in the lane keeping assist mode.

[0031] The automatic emergency avoidance mode is a mode in which automatic emergency avoidance steering is performed to automatically avoid a collision with another vehicle, etc. The automatic parking mode is a mode in which automatic parking steering is performed to automatically park the vehicle in a parking space. For example, Intelligent Parking Assist (IPA) is an example of an application that runs in the automatic parking mode.

[0032] In the lane keeping assist mode, the host ECU 201 sets an automatic steering command value θ * c,ad In the automatic emergency avoidance mode, the host ECU 201 sets an automatic steering command value θ * c,ad In the automatic parking mode, the host ECU 201 sets an automatic steering command value θ * c,ad Such an automatic steering command value θ * c,ad Since the process of setting the automatic steering command value θ is well known, a detailed description thereof will be omitted here. * c,ad Set to zero.

[0033] The host ECU 201 also outputs a mode signal S indicating the driving mode. mode The mode signal S mode , the automatic steering command value θ set by the host ECU 201 * c,ad and the vehicle speed V are provided to the motor control ECU 202 via the in-vehicle network. tbThe output signal of the rotation angle sensor 23 is input to the motor control ECU 202. The motor control ECU 202 controls the electric motor 18 based on these input signals and information provided by the host ECU 201.

[0034] [2] Motor control ECU202 FIG. 2 is a block diagram for explaining the electrical configuration of motor control ECU 202. As shown in FIG.

[0035] The motor control ECU 202 includes a microcomputer 40, a drive circuit (inverter circuit) 31 controlled by the microcomputer 40 to supply power to the electric motor 18, and a current flowing through the electric motor 18 (hereinafter referred to as the "motor current I m,int The device is provided with a current detection circuit 32 for detecting the current.

[0036] The microcomputer 40 includes a CPU and memory (ROM, RAM, nonvolatile memory, etc.), and functions as a plurality of functional processing sections by executing predetermined programs. The plurality of functional processing sections include a rotation angle calculation section 41, a reduction ratio division section 42, a first dead-band processing section 43, an assist torque command value setting section 44, a second dead-band processing section 45, a manual steering command value generation section 46, an integrated angle command value calculation section 47, an angle control section 48, a torque control section 49, a first dead-band width setting section 51, and a second dead-band width setting section 52.

[0037] The rotation angle calculation unit 41 calculates the rotor rotation angle θ of the electric motor 18 based on the output signal of the rotation angle sensor 23. m,int The reduction ratio division unit 42 calculates the rotor rotation angle θ m,int By dividing by the reduction ratio N, the rotor rotation angle θ m,int The rotation angle (actual steering angle) of the output shaft 9 is θ c,int Convert to.

[0038] The first dead zone processing unit 43 receives the steering torque T tb The first dead zone processing unit 43 receives the steering torque T tbis within the range of -W1 / 2 or more and W1 / 2 or less (first dead band region), zero is set as the steering torque T after the first dead band processing. tb,de (See FIG. 10, which will be described later.)

[0039] Steering torque T tb In the region where [T tb +(W1 / 2)] is the steering torque T after the first dead band processing. tb,de The steering torque T tb In the region where [T tb -(W1 / 2)] is the steering torque T after the first dead zone processing. tb,de The first dead zone width W1 is set by the first dead zone width setting unit 51.

[0040] The assist torque command value setting unit 44 sets the assist torque command value T * m,md The assist torque command value setting unit 44 sets the assist torque command value T tb Based on this, the assist torque command value T * m,md Set the steering torque T tb Assist torque command value T * m,md An example of the configuration is shown in Figure 3.

[0041] Assist torque command value T * m,md is set to a positive value when the electric motor 18 is to generate a steering assist force for steering to the left, and is set to a negative value when the electric motor 18 is to generate a steering assist force for steering to the right. * m,md is the steering torque T tb The steering torque T tb The assist torque command value T * m,md is the steering torque Ttb The larger the absolute value of the assist torque command value T * m,md is set so that the absolute value thereof decreases as the vehicle speed V increases.

[0042] The assist torque command value setting unit 44 sets the steering torque T tb is multiplied by a preset constant to obtain the assist torque command value T * m,md may be calculated.

[0043] The second dead zone processing unit 45 receives the assist torque command value T * m,md The second dead zone processing unit 45 receives the assist torque command value T * m,md is within the range of -W2 / 2 or more and W2 / 2 or less (second dead band area), zero is set as the assist torque command value T * m,md,de Output as

[0044] Assist torque command value T * m,md In the region where [T * m,md +(W2 / 2)] is the assist torque command value T * m,md,de The assist torque command value T * m,md In the region where [T * m,md -(W2 / 2)] is the assist torque command value T after the second dead band processing. * m,md,de The second dead zone width W2 is set by the second dead zone width setting unit 52.

[0045] When the driver operates the steering wheel 2, the manual steering command value generating unit 46 generates a steering angle according to the steering wheel operation as a manual steering command value θ * c,md The manual steering command value generating unit 46 is provided to set the steering torque T after the first dead zone processing as tb,de and the assist torque command value T after the second dead band processing * m,md,de and the manual steering command value θ * c,md In this embodiment, the manual steering command value generating unit 46 generates the manual steering command value θ using the reference EPS model. * c.md Set.

[0046] FIG. 4 is a schematic diagram showing an example of a reference EPS model used in the manual steering command value generating unit 46.

[0047] This reference EPS model is a single-inertia model including a lower column. The lower column corresponds to the output shaft 9 and the worm wheel 21. In FIG. 4, J c is the inertia of the lower column, and θ c is the rotation angle of the lower column, and T tb,de is the steering torque after the first dead band processing. This reference EPS model uses the steering torque T tb,de and the assist torque command value T after the second dead band processing * m,md,de The torque N·T acting on the output shaft 9 from the electric motor 18 is * m,md,de and road load torque T rl The rotation angle θ of the lower column when c This is a model for generating (estimating) the road load torque T rl is expressed by the following equation (1) using the spring constant k and the viscous damping coefficient c.

[0048] 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, etc.

[0049] The equation of motion of the reference EPS model is expressed by the following equation (2).

[0050] J c ·d 2 θ c / dt 2 =T tb,de +N·T * m,md,de -k θ c -c(dθ c / dt) …(2) The manual steering command value generating unit 46 calculates the rotation angle θ of the lower column by solving the differential equation of the formula (2). c Then, the manual steering command value generating unit 46 calculates the obtained rotation angle θ of the lower column. c The manual steering command value θ * c,md Set as.

[0051] The integrated angle command value calculation unit 47 calculates the automatic steering command value θ set by the host ECU 201. * c,ad Manual steering command value θ * c,md The integrated angle command value θ * c,int Calculate the following.

[0052] The angle control unit 48 calculates the integrated angle command value θ * c,int Based on this, the motor torque command value T * m,int The torque control unit 49 calculates the motor torque of the electric motor 18 in accordance with the motor torque command value T * m,int That is, the control unit consisting of the angle control unit 48 and the torque control unit 49 controls the actual steering angle θ c,int (The rotation angle of the output shaft 9 is θ c,int ) is the integrated angle command value θ *c,int The drive circuit 31 is controlled so that the angle of the rotational axis 48 approaches the angle of the rotational axis 49. The operations of the angle control unit 48 and the torque control unit 49 will be described in detail later.

[0053] The first dead zone width setting unit 51 and the second dead zone width setting unit 52 each receive the mode signal S mode The first dead zone width W1 and the second dead zone width W2 are set based on the (operation mode). The operations of the first dead zone width setting unit 51 and the second dead zone width setting unit 52 will be described in detail later.

[0054] FIG. 5 is a block diagram showing the configuration of the angle control unit 48.

[0055] The angle control unit 48 calculates the integrated angle command value θ * c,int Based on the motor torque command value T * m,int The angle control unit 48 includes a low-pass filter (LPF) 61, a feedback control unit 62, a feedforward control unit 63, a disturbance torque estimation unit 64, a torque addition unit 65, a disturbance torque compensation unit 66, a reduction ratio division unit 67, and a reduction ratio multiplication unit 68.

[0056] The reduction ratio multiplication unit 68 multiplies the motor torque command value T * m,int is multiplied by the reduction ratio N of the reducer 19 to obtain the motor torque command value T * m,int is the output shaft torque command value T * c,int (=N·T * m,int )

[0057] The low-pass filter 61 calculates the integrated angle command value θ * c,int The integrated angle command value θ after low-pass filtering is * c,intf is provided to the feedback control section 62 and the feedforward control section 63.

[0058] The feedback control unit 62 calculates the actual steering angle θ calculated by the reduction ratio division unit 42 (see FIG. 2). c,int is the integrated angle command value θ after low-pass filtering. * c,intf The feedback control unit 62 includes an angle deviation calculation unit 62A and a PD control unit 62B. The angle deviation calculation unit 62A calculates an integrated angle command value θ * c,intf and the actual steering angle θ calculated by the reduction ratio division unit 42. c,int Deviation Δθ c,int (=θ * c,intf -θ c,int ) is calculated. The angle deviation calculation unit 62A calculates the integrated angle command value θ * c,intf and the steering angle estimated value ^θ calculated by the disturbance torque estimator 64. c,int deviation from (θ * c,intf -^θ c,int ) and the angle deviation Δθ c,int It may be calculated as follows.

[0059] The PD control unit 62B calculates the angle deviation Δθ calculated by the angle deviation calculation unit 62A. c,int By performing PD calculation (proportional differential calculation) on the feedback control torque T fb,int Calculate the feedback control torque T fb,int is given to the torque adder 65.

[0060] The feedforward control unit 63 is provided to compensate for a delay in response due to the inertia of the electric power steering system 1, thereby improving the response of the control. The feedforward control unit 63 includes an angular acceleration calculation unit 63A and an inertia multiplication unit 63B. The angular acceleration calculation unit 63A calculates an integrated angle command value θ * c,intf By taking the second derivative, the target angular acceleration d 2 θ * c,intf / dt 2 Calculate the following.

[0061] The inertia multiplication unit 63B multiplies the target angular acceleration d calculated by the angular acceleration calculation unit 63A by 2 θ * c,intf / dt 2 is multiplied by the inertia J of the electric power steering system 1 to obtain the feedforward control torque T ff,int (=J·d 2 θ * c,intf / dt 2 The inertia J can be calculated from, for example, a physical model (see FIG. 6) of the electric power steering system 1, which will be described later. The feedforward control torque T ff,int is given to the torque adder 65 as an inertia compensation value.

[0062] The torque adder 65 calculates the feedback control torque T fb,int to the feedforward control torque T ff,int By adding fb,int +T ff,int ) is calculated.

[0063] The disturbance torque estimating unit 64 is provided to estimate a nonlinear torque (disturbance torque: torque other than motor torque) that occurs as a disturbance in the plant (the object to be controlled by the electric motor 18). The disturbance torque estimating unit 64 estimates an output shaft torque command value T * c,int (=N·T * m,int ) and the actual steering angle θ, which is the plant output c,int Based on this, the disturbance torque (disturbance load) T lc , steering angle θ c,int and steering angle differential value (angular velocity) dθ c,int / dt is estimated. lc , steering angle θ c,int and steering angle differential value (angular velocity) dθ c,int / dt estimates, respectively, lc , ^θ c,int and d^θ c,int The disturbance torque estimating section 64 will be described in detail later.

[0064] The disturbance torque estimated value ^T calculated by the disturbance torque estimator 64 lc is given to the disturbance torque compensator 66 as a disturbance torque compensation value.

[0065] The disturbance torque compensator 66 calculates the basic torque command value (T fb,int +T ff,int ) to the estimated disturbance torque ^T lc By subtracting the output torque command value T * c,int (=T fb,int +T ff,int -^T lc ) is calculated. This results in the output shaft torque command value T * c,int (torque command value for output shaft 9) is obtained.

[0066] Output shaft torque command value T * c,int is given to the reduction ratio division unit 67. The reduction ratio division unit 67 calculates the output shaft torque command value T * c,int By dividing by the reduction ratio N, the motor torque command value T * m,int This motor torque command value T * m,int is given to the torque control section 49 (see FIG. 2).

[0067] The disturbance torque estimation unit 64 will be described in detail. The disturbance torque estimation unit 64 uses, for example, a physical model 101 of the electric power steering system 1 shown in FIG. 6 to estimate the disturbance torque T lc , steering angle θ c,int and angular velocity dθ c,int It consists of a disturbance observer that estimates / dt.

[0068] This physical model 101 includes a plant (an example of a motor-driven object) 102 including an output shaft 9 and a worm wheel 21 fixed to the output shaft 9. The plant 102 receives a steering torque T tbis applied, and a road load torque T rl is given.

[0069] Furthermore, the plant 102 receives an output shaft torque command value T * c,int (=N·T * m,int ) is given, and friction torque T f is given.

[0070] When the inertia of the plant 102 is J, the equation of motion for the inertia of the physical model 101 is expressed by the following equation (3).

[0071]

number

[0072] The state equation for the physical model 101 in FIG. 6 is expressed by the following equation (4).

[0073]

number

[0074] The state equation is expanded to a system including the unknown input vector u2 as one of the states. The state equation of the expanded system (expanded state equation) is expressed by the following equation (5).

[0075]

number

[0076]

number

[0077] From the extended state equation of the above formula (5), a disturbance observer (extended state observer) expressed by the following formula (7) is constructed.

[0078]

number

[0079]

number

[0080] The disturbance torque estimation unit 64 calculates the state variable vector ^x based on the equation (7).e Calculate the following.

[0081] FIG. 7 is a block diagram showing the configuration of the disturbance torque estimating unit 64.

[0082] The disturbance torque estimation unit 64 includes an input vector input unit 81, an output matrix multiplication unit 82, a first addition unit 83, a gain multiplication unit 84, an input matrix multiplication unit 85, a system matrix multiplication unit 86, a second addition unit 87, an integration unit 88, and a state variable vector output unit 89.

[0083] The output shaft torque command value T calculated by the reduction ratio multiplication unit 68 (see FIG. 5) * c,int (=N·T * m,int ) is given to the input vector input unit 81. The input vector input unit 81 outputs the input vector u1.

[0084] The output of the integrator 88 is the state variable vector ^x e (See equation (8) above.) At the start of calculation, the state variable vector ^x e The initial value is given as the state variable vector ^x e The initial value of is, for example, 0.

[0085] The system matrix multiplication unit 86 multiplies the state variable vector ^x e In the system matrix A e The output matrix multiplication unit 82 multiplies the state variable vector ^x e into the output matrix C e Multiply by.

[0086] The first adder 83 calculates the actual steering angle θ calculated by the reduction ratio divider 42 (see FIG. 2). c,int From the output vector (measurement value) y, which is e ^x e ) is subtracted from the output vector y. That is, the first adder 83 subtracts the output vector estimate ^y(=C e ^x eThe gain multiplication unit 84 multiplies the output (y-^y) of the first addition unit 83 by the observer gain L (see equation (7) above).

[0087] The input matrix multiplication unit 85 multiplies the input vector u1 output from the input vector input unit 81 by the input matrix B e The second adder 87 multiplies the output (Be·u1) of the input matrix multiplier 85 by the output (A e ^x e ) and the output (L(y-^y)) of the gain multiplication unit 84, the differential value d^x of the state variable vector is obtained. e The integrator 88 calculates the output (d^x e / dt), the state variable vector ^x e The state variable vector output unit 89 calculates the state variable vector ^x e Based on this, the disturbance torque estimate ^T lc , steering angle estimate ^θ c,int and the estimated angular velocity d^θ c,int Calculates / dt.

[0088] Unlike the extended state observer described above, a general disturbance observer consists of an inverse model of the plant and a low-pass filter. The equation of motion of the plant is expressed by equation (3) as described above. Therefore, the inverse model of the plant is expressed by the following equation (9).

[0089]

number

[0090] The disturbance torque estimating unit 64 may be a general disturbance observer that is configured from an inverse model of the plant and a low-pass filter.

[0091] 8 is a block diagram showing the electrical configuration of torque control unit 49. Torque control unit 49 includes a motor current command value calculation unit 91, a current deviation calculation unit 92, a PI control unit 93, and a PWM (Pulse Width Modulation) control unit 94.

[0092] The motor current command value calculation unit 91 calculates the motor torque command value T * m,int The torque constant K of the electric motor 18 t By dividing by, the motor current command value I * m,int Calculate the following.

[0093] The current deviation calculation unit 92 calculates the motor current command value I obtained by the motor current command value calculation unit 91. * m,int and the motor current I detected by the current detection circuit 32 m,int Deviation ΔI m,int (=I * m,int -I m,int ) is calculated.

[0094] The PI control unit 93 calculates the current deviation ΔI m,int By performing a PI calculation (proportional integral calculation) on m,int The motor current command value I * m,int The PWM control unit 94 generates a PWM control signal with a duty ratio corresponding to the drive command value and supplies it to the drive circuit 31. As a result, power corresponding to the drive command value is supplied to the electric motor 18.

[0095] Next, a detailed description will be given of the operations of the first dead-band width setting unit 51 and the second dead-band width setting unit 52. The first dead-band width setting unit 51 performs a first dead-band width setting process to set the first dead-band width W1. The second dead-band width setting unit 52 performs a second dead-band width setting process to set the second dead-band width W2.

[0096] Fig. 9 is a flowchart showing the procedure of the first dead-zone width setting process performed by the first dead-zone width setting unit 51. The first dead-zone width setting process shown in Fig. 9 is repeatedly performed at predetermined calculation intervals.

[0097] The first dead zone width setting unit 51 is configured to set the mode signal S mode Based on this, it is determined whether the driving mode is the normal mode, the automatic parking mode, the automatic emergency avoidance mode, or the lane keeping assist mode (steps S1, S2, S3, S4).

[0098] If the operation mode is the normal mode (step S1: YES), the first dead band width setting unit 51 sets the first dead band width W1 to a preset first dead band width W for the normal mode. 1_standard (Step S5). Then, the first dead-band width setting unit 51 ends the processing for the current calculation cycle.

[0099] If the driving mode is the automatic parking mode (step S2: YES), the first dead band width setting unit 51 sets the first dead band width W1 to a preset first dead band width W for the automatic parking mode. 1_park (Step S6). Then, the first dead-band width setting unit 51 ends the processing for the current calculation cycle.

[0100] If the operation mode is the automatic emergency avoidance mode (step S3: YES), the first dead band width setting unit 51 sets the first dead band width W1 to a preset first dead band width W for the automatic emergency avoidance mode. 1_emergency (Step S7). Then, the first dead-band width setting unit 51 ends the processing for the current calculation cycle.

[0101] If the driving mode is the lane keeping assist mode (step S4: YES), the first dead band width setting unit 51 sets the first dead band width W1 to a predetermined first dead band width W for the lane keeping assist mode. 1_lane (Step S8). Then, the first dead-band width setting unit 51 ends the processing for the current calculation cycle.

[0102] W 1_park , W 1_emergency and W 1_lane is W 1_park >W 1_emergency >W 1_lane It is preferable that the relationship be set so as to satisfy the following.

[0103] The reason for this will be explained below. When the first dead zone width W1 is set to a large value, the manual steering angle command value θ * c,md Therefore, the vehicle can follow the target route better. On the other hand, it becomes more difficult for the driver to intervene in the steering.

[0104] In the automatic parking mode, it is necessary to improve the tracking ability. However, in the automatic parking mode, the steering wheel 2 is rotated at a relatively high speed, so that the steering wheel 2 is likely to suddenly accelerate or stop. When the steering wheel 2 suddenly accelerates or stops, the inertia torque of the steering wheel 2 increases the twist of the torsion bar 10, and the steering torque T detected by the torque sensor 12 tb In this case, even though the steering wheel is not in a hands-off state, the manual steering angle command value θ * c,md becomes larger, and the tracking ability to the target driving route deteriorates. * c,md In order to prevent the first dead band width W1 from becoming large, it is preferable to set the first dead band width W1 to a large value in the automatic parking mode. In this way, if the first dead band width W1 is set to a large value, the steering intervention function will be reduced, but since the automatic parking mode is premised on a hands-free state, the need for the steering intervention function is low, so this is not a problem.

[0105] In the tracking control in the lane keeping assist mode, the steering wheel 2 does not suddenly accelerate or stop, so the manual steering angle command value θ * c,md Therefore, there is little need to increase the first dead-band width W1 to improve tracking ability. On the other hand, in the lane keeping assist mode, the steering intervention function becomes important for lane changes, etc. Therefore, it is preferable to set the first dead-band width W1 to a small value in the lane keeping assist mode.

[0106] In the automatic emergency avoidance mode, both tracking ability and steering intervention function are required, so the first dead band width W1 is set to be equal to the first dead band width W 1_park and the first dead zone width W in lane keeping assist mode 1_lane It is preferable to set it to an intermediate value between

[0107] FIG. 10 is a graph showing a specific example of the input / output characteristics of the first dead band processing unit 43. In FIG.

[0108] The broken line L1 indicates that the first dead band width W1 is W 1_lane The broken line L2 shows the input / output characteristics of the first dead band processing unit 43 when the first dead band width W1 is set to W 1_emergency The broken line L3 shows the input / output characteristics of the first dead band processing unit 43 when the first dead band width W1 is set to W 1_park 1 shows the input / output characteristics of the first dead band processing unit 43 when the first dead band width W 1_standard is W 1_lpark and W 1_lane It is preferable to set it to an intermediate value between

[0109] The second dead-band width setting process performed by the second dead-band width setting unit 52 is the same as the first dead-band width setting process in Fig. 9. However, in the second dead-band width setting process, W1 and W 1_standard , W 1_park , W 1_emergency and W 1_laneare W2 and W 2_standard , W 2_park , W 2_emergency and W 2_lane In this case, too, W 2_park , W 2_emergency and W 2_lane is W 2_park >W 2_emergency >W 2_lane It is preferable that the relationship be set so as to satisfy the following.

[0110] In the above-described embodiment, the first dead zone width W1 and the second dead zone width W2 are set according to the operation mode, thereby enabling appropriate cooperative control according to the operation mode.

[0111] As shown by the broken lines in FIG. 2, the first dead zone width setting unit 51 and the second dead zone width setting unit 52 are supplied with a mode signal S mode In addition to the above, the vehicle speed V may be input. When the driving mode is the lane keeping assist mode, the first dead zone width setting unit 51 and the second dead zone width setting unit 52 each set the first dead zone width W 1_lane and the second dead band width W 2_lane may be set according to the vehicle speed V.

[0112] FIG. 11 shows the first dead-band width W relative to the vehicle speed V calculated by the first dead-band width setting unit 51. 1_lane 10 is a graph showing an example of setting the

[0113] In the low speed range of vehicle speed V between 0 and V1, the first dead band width W 1_lane is set to a first predetermined value A. When the vehicle speed V is in the medium speed range of V1 to V2, the first dead band width W 1_lane is set according to a characteristic that it gradually decreases from the first predetermined value A to the second predetermined value B as the vehicle speed V increases. In the high speed range of the vehicle speed V between V2 and V3, the first dead band width W 1_lane is set to a second predetermined value B.

[0114] Second dead band width W 2_lane Regarding the first dead band width W 1_lane is set in the same way.

[0115] The first dead band width W 1_lane The reason why is set as shown in FIG. 11 will be explained. When the vehicle speed V is high, even a small movement of the steering wheel 2 will result in a large change in the vehicle behavior. When the vehicle speed V is low, even a large movement of the steering wheel 2 will not result in a large change in the vehicle behavior. For this reason, when the vehicle speed V is low, the automatic steering angle command value θ * c,ad is allowed to change significantly, but when the vehicle speed V is high, the automatic steering angle command value θ * c,ad is not allowed to vary significantly.

[0116] Therefore, the automatic steering angle command value θ * c,ad At low speeds where there is a possibility that the value of the first dead band width W 1_lane On the other hand, the automatic steering angle command value θ * c,ad At high speeds where there are no significant changes, the first dead zone width W 1_lane is made smaller.

[0117] Even when the driving mode is the automatic parking mode or the automatic emergency avoidance mode, the first dead zone width setting unit 51 and the second dead zone width setting unit 52 each set the first dead zone width W 1_park ,W 1_emergency and the second dead band width W 2_park ,W 2_emergency may be set in accordance with the vehicle speed V. In this case, the first dead-band width setting unit 51 and the second dead-band width setting unit 52 each set the first dead-band width W 1_park ,W 1_emergency and the second dead band width W 2_park ,W 2_emergency may be set to be large.

[0118] In the above-described embodiment, both the first dead band width W1 used in the first dead band processing unit 43 and the second dead band width W2 used in the second dead band processing unit 45 are controlled based on the driving mode only or the driving mode and the vehicle speed V, but only one of the first dead band width W1 and the second dead band width W2 may be controlled based on the driving mode only or the driving mode and the vehicle speed V.

[0119] [3] Modification of motor control ECU 202 Fig. 12 is a block diagram for explaining the electrical configuration of a modified example of motor control ECU 202. In Fig. 12, parts corresponding to those in Fig. 2 described above are denoted by the same reference numerals as in Fig. 2.

[0120] In the modified example of Fig. 12, the configuration of the functional processing unit in the microcomputer 40A is different from that in Fig. 2. Specifically, in the modified example of Fig. 12, a third dead band processing unit 53 and a third dead band width setting unit 54 are provided instead of the first dead band processing unit 43, the second dead band processing unit 45, the first dead band width setting unit 51, and the second dead band width setting unit 52 in Fig. 2.

[0121] The third dead zone processing unit 53 is disposed before both the assist torque command value setting unit 44 and the manual steering command value generating unit 46. When the third dead zone width is W3, the third dead zone processing unit 53 calculates the steering torque T tb is within the range of -W3 / 2 or more and W3 / 2 or less (third dead band area), zero is set to the steering torque T tb,de Output as

[0122] Steering torque T tb In the region where [T tb +(W3 / 2)] is the steering torque T after the third dead band processing. tb,de The steering torque T tb In the region where [T tb -(W3 / 2)] is the steering torque T after the third dead band processing. tb,de Output as

[0123] The third dead zone width W3 is set by the third dead zone width setting unit 54. The third dead zone width setting unit 54 is configured to set the third dead zone width W3 in response to the mode signal S mode The third dead band width W3 is set based on the (operation mode). The third dead band width setting unit 54 performs a third dead band width setting process for setting the third dead band width W3.

[0124] 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. 9. However, in the third dead-band width setting process, W1 and W 1_standard , W 1_park , W 1_emergency and W 1_lane are W3 and W 3_standard , W 3_park , W 3_emergency and W 3_lane In this case, too, W 3_park , W 3_emergency and W 3_lane is W 3_park >W 3_emergency >W 3_lane It is preferable that the relationship be set so as to satisfy the following.

[0125] In the modification of FIG. 12, the assist torque command value setting unit 44 sets the steering torque T tb,de and the vehicle speed V, the assist torque command value T * m,md The manual steering command value generating unit 46 sets the assist torque command value T * m,md and the steering torque T after the third dead band processing tb,de Based on this, the manual steering command value θ * c,md Calculate the following.

[0126] Specifically, the manual steering command value generating unit 46 calculates T tb,de After the third dead band processing, the steering torque T tb,de Substituting T in equation (2), * m,md,de The assist torque command value T * m,mdBy substituting and solving the differential equation (2), the rotation angle θ of the lower column is c Calculate the rotation angle θ c Actual manual steering angle θ c,md Set as.

[0127] In this modification, the third dead band width W3 is also set in accordance with the operation mode, so that appropriate cooperative control can be performed in accordance with the operation mode.

[0128] As shown by the broken line in FIG. 12, the third dead zone width setting unit 54 receives the mode signal S mode In addition to the above, the vehicle speed V may be input. When the driving mode is the lane keeping assist mode, the third dead zone width setting unit 54 sets the third dead zone width W 3_lane is the first dead zone width W 1_lane Similarly, it may be set according to the vehicle speed V.

[0129] In addition, even when the driving mode is the automatic parking mode or the automatic emergency avoidance mode, the third dead band width W 3_park ,W 3_emergency may be set in accordance with the vehicle speed V. In this case, the third dead band width setting unit 54 sets the third dead band width W 3_park ,W 3_emergency may be set to be large.

[0130] In the above-described embodiment and modified example, when the operation mode is the normal mode, the assist torque command value T * m,md Specifically, in the normal mode, the electric motor 18 may be controlled based only on the motor torque command value T * m,int Instead, the assist torque command value T * m,md may be input to the torque control unit 49.

[0131] In the above embodiment, an example was shown in which the present invention is applied to motor control of a column-type EPS, but the present invention can also be applied to motor control of EPS other than column types.

[0132] Although the embodiments of the present invention have been described in detail, these are merely examples used to clarify the technical contents of the present invention, and the present invention should not be construed as being limited to these examples, and the scope of the present invention is limited only by the appended claims. [Explanation of symbols]

[0133] 1... electric power steering device, 3... steered wheels, 4... steering mechanism, 18... electric motor, 43... first dead zone processing unit, 44... assist torque command value setting unit, 45... second dead zone processing unit, 46... manual steering command value generation unit, 47... integrated angle command value calculation unit, 48... angle control unit, 49... torque control unit, 50... hands on / off determination unit, 51... first dead zone width setting unit, 52... second dead zone width setting unit, 53... third dead zone width processing unit, 54... third dead zone width setting unit, 201... host ECU 201, 202... motor control ECU

Claims

1. a torque detection unit for detecting a steering torque; an assist torque command value setting unit that sets an assist torque command value using the steering torque; a manual steering command value generating unit that generates a manual steering command value using the steering torque and the assist torque command value; an integrated angle command value calculation unit that calculates an integrated angle command value by adding the manual steering command value to an automatic steering command value; a control unit that controls the angle of an electric motor for steering angle control based on the integrated angle command value; a dead band processing unit provided for at least one of the steering torque input to the manual steering command value generation unit, the assist torque command value input to the manual steering command value generation unit, and the steering torque input to the assist torque command value setting unit; a dead-band width setting unit that sets a dead-band width of at least one of the dead-band processing units according to an operation mode.

2. Further including a vehicle speed detection unit for detecting a vehicle speed, The motor control device according to claim 1 , wherein the dead-zone width setting unit is configured to set the dead-zone width of the dead-zone processing unit in consideration of the vehicle speed.

3. 3. The motor control device according to claim 1, wherein the driving modes include a lane keeping assist mode that prevents the vehicle from deviating from its lane, an automatic emergency avoidance mode that automatically avoids a collision with another vehicle, and an automatic parking mode that automatically parks the vehicle.

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