Motor control device

Abstract

In this invention, a manual steering command value calculator is configured to use road surface information, including information related to road surface reaction torque, to calculate manual steering command values if a first condition that at least one of input torques for which a dead zone processing part is provided is outside a dead zone range is satisfied, and, if the first condition is not satisfied, the road surface information is not used for the calculation of manual steering command values. When a warning vibration torque is applied, the manual steering command value calculator uses the road surface information to calculate manual steering command values for a certain period of time from the time point when the condition changes from satisfying the first condition to not satisfying the first condition.

Description

[Technical Field]

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

[0002] Patent Document 1 listed below discloses a motor control device that performs angle feedback control of an electric motor based on an integrated angle command value obtained by adding a manual steering command value to an automatic steering command value.

[0003] Patent Document 2 listed below discloses a vehicle steering device including a vibration torque calculation unit that calculates a vibration torque for warning when it is determined that the vehicle is deviating from its lane, and a current control unit that applies vibration to the steering wheel by controlling an electric motor using the vibration torque calculated by the vibration torque calculation unit. The vibration torque calculation unit sets the value of the vibration torque so that the greater the steering torque detected by the torque sensor, the greater the value of the vibration torque, and the smaller the steering torque, the smaller the value of the vibration torque. Specifically, the vibration torque calculation unit stores in advance a map that stores the relationship between the steering torque and the peak value of the vibration torque, and sets the vibration torque based on the steering torque detected by the torque sensor and the map. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 2019-194059 [Patent Document 2] Japanese Patent Application Laid-Open No. 2017-65587 Summary of the Invention [Problem to be solved by the invention]

[0005] An object of the present invention is to provide a motor control device that can control an electric motor based on an integrated angle command value obtained by adding a manual steering command value to an automatic steering command value, and that is suitable for applying warning vibrations to the steering wheel depending on the driving state of the vehicle. [Means for solving the problem]

[0006] One embodiment of the present invention is a motor control device for drive control of an electric motor for steering angle control, the motor control device including an assist torque command value calculation unit that calculates an assist torque command value using a steering torque, a manual steering command value calculation unit that calculates 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 the electric motor based on the integrated angle command value, and a dead band processing unit that is provided for at least one of the input torques, where the steering torque input to the manual steering command value calculation unit, the assist command value input to the manual steering command value calculation unit, and the steering torque input to the assist control unit are taken as input torques. and a warning vibration imparting unit for imparting a vibration torque as a component of a motor torque command value of the electric motor, wherein the manual steering command value calculation unit is configured to use road surface information including information on road surface reaction torque in calculating the manual steering command value when a first condition is satisfied that at least one of the input torques for which the dead band processing unit is provided is outside the range of the dead band, and not to use the road surface information in calculating the manual steering command value when the first condition is not satisfied, and wherein when the warning vibration torque is imparted, the manual steering command value calculation unit uses the road surface information in calculating the manual steering command value for a certain period of time from the point in time when the state changes from satisfying the first condition to not satisfying the first condition.

[0007] This configuration provides a motor control device suitable for applying warning vibrations to the steering wheel depending on the driving state of the vehicle.

[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 Tas relative to the steering torque Ttb. [Figure 4] FIG. 4 is a block diagram showing the configuration of the angle control unit. [Figure 5] FIG. 5 is a schematic diagram showing an example of the configuration of a physical model of an electric power steering system. [Figure 6] FIG. 6 is a block diagram showing the configuration of the disturbance torque estimating unit. [Figure 7] FIG. 7 is a schematic diagram showing the configuration of the torque control unit. [Figure 8] FIG. 8 is a block diagram showing the configuration of the manual steering command value calculation unit. [Figure 9] FIG. 9 is a graph showing input / output characteristics of the first dead band processing unit. [Figure 10] FIG. 10 is a graph showing the input / output characteristics of the second dead band processing unit. [Figure 11A] FIG. 11A is a flowchart showing a part of the procedure of the determination process executed by the determination unit in the driving assistance mode. [Figure 11B] FIG. 11B is a flowchart showing part of the procedure of the determination process executed by the determination unit in the driving assistance mode. [Figure 12] FIG. 12 is a time chart showing an example of a vibration waveform in the warning mode. DETAILED DESCRIPTION OF THE INVENTION

[0010] [Description of the embodiment of the present invention] One embodiment of the present invention is a motor control device for drive control of an electric motor for steering angle control, the motor control device including an assist torque command value calculation unit that calculates an assist torque command value using a steering torque, a manual steering command value calculation unit that calculates 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 the electric motor based on the integrated angle command value, and a dead band processing unit that is provided for at least one of the input torques, where the steering torque input to the manual steering command value calculation unit, the assist command value input to the manual steering command value calculation unit, and the steering torque input to the assist control unit are taken as input torques. and a warning vibration imparting unit for imparting a vibration torque as a component of a motor torque command value of the electric motor, wherein the manual steering command value calculation unit is configured to use road surface information including information on road surface reaction torque in calculating the manual steering command value when a first condition is satisfied that at least one of the input torques for which the dead band processing unit is provided is outside the range of the dead band, and not to use the road surface information in calculating the manual steering command value when the first condition is not satisfied, and wherein when the warning vibration torque is imparted, the manual steering command value calculation unit uses the road surface information in calculating the manual steering command value for a certain period of time from the point in time when the state changes from satisfying the first condition to not satisfying the first condition.

[0011] This configuration provides a motor control device suitable for applying warning vibrations to the steering wheel depending on the driving state of the vehicle.

[0012] In one embodiment of the present invention, the dead zone processing unit includes a first dead zone processing unit provided for the steering torque input to the manual steering command value calculation unit, and a second dead zone processing unit provided for the assist command value input to the manual steering command value calculation unit.

[0013] In one embodiment of the present invention, the road surface information is calculated based on an integrated torque command value corresponding to the integrated angle command value and the steering angle, and is a high-frequency component of an estimated value of disturbance torque applied to the steering shaft.

[0014] In one embodiment of the present invention, the warning vibration imparting unit is configured to output a vibration torque command value corresponding to the target warning vibration waveform, and the vibration torque command value is added to an integrated torque command value corresponding to the integrated angle command value.

[0015] In one embodiment of the present invention, the warning vibration applying unit is configured to output a vibration angle command value corresponding to the target warning vibration waveform, and the vibration angle command value is added to the integrated angle command value.

[0016] 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.

[0017] 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.

[0018] 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.

[0019] 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.

[0020] A torque sensor 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.

[0021] 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.

[0022] 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.

[0023] 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.

[0024] 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.

[0025] In the following, the reduction ratio (gear ratio) of the reducer 19 may be expressed as N. The reduction ratio N is determined by the rotation angle of the worm wheel 21, that is, the worm wheel angle θ ww The worm gear angle θ is the rotation angle of the worm gear 20 relative to the wg The ratio (θ wg / θ ww )

[0026] 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.

[0027] 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.

[0028] The torque applied to the output shaft 9 (an example of a drive target of the electric motor 18) includes the motor torque from the electric motor 18 and a disturbance torque T lc Disturbance torque other than the motor torque T lc The steering torque T tb, road load torque (road reaction torque) T rl , friction torque T f etc. are included.

[0029] 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, the force generated by steering inertia, etc.

[0030] 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.

[0031] The vehicle is equipped with a CCD (Charge Coupled Device) camera 25 that captures images of the road ahead 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 the like.

[0032] The CCD camera 25, GPS 26, radar 27, and map information memory 28 are connected to a host ECU (Electronic Control Unit) 201 for performing driving assistance control. Based on the information obtained by the CCD camera 25, GPS 26, and radar 27, as well as 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.

[0033] In this embodiment, there are two driving modes: a normal mode and a driving assistance mode. In this embodiment, in the driving assistance mode, the host ECU 201 determines an automatic steering command value θ for the driving assistance mode based on information obtained by the CCD camera 25, the GPS 26, the radar 27, and map information. ad,cmd Generate.

[0034] In this embodiment, the driving assistance is a lane centering assist (LCA) for the vehicle to automatically follow the center of the lane. ad,cmd is a target value of the steering angle (in this embodiment, the rotation angle of the pinion shaft 13) for driving the vehicle along the center of the lane. ad,cmd Since the process of setting the target position is well known, detailed description thereof will be omitted here. Note that the automatic steering control (driving assistance control) may be, for example, lane keeping assist (LKA) control for keeping the vehicle within the lane.

[0035] Furthermore, the host ECU 201 determines whether or not there is a high possibility that the vehicle will deviate from the lane based on the image captured by the CCD camera 25. In this embodiment, when the host ECU 201 determines that there is a high possibility that the vehicle will deviate from the lane, it sets a vibration torque command value T wa,cmd Generate and output.

[0036] In the following, the vibration torque command value T wa,cmd The mode in which the warning mode signal S is output is referred to as the "warning mode." The host ECU 201 outputs a warning mode signal S indicating whether the warning mode is in effect. wa,mode Output.

[0037] The host ECU 201 also outputs a driving mode signal S indicating whether the driving mode is the normal mode or the driving assistance mode. dr,mode Generates the operation mode signal S dr,mode , automatic steering command value θ ad,cmd , warning mode signal S wa,mode and vibration torque command value T wa,cmd is provided to the motor control ECU 202 via the in-vehicle network.

[0038] The steering torque T detected by the torque sensor 12 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.

[0039] FIG. 2 is a block diagram for explaining the electrical configuration of motor control ECU 202. As shown in FIG.

[0040] The following mainly describes the case where the driving mode is the driving assistance mode.

[0041] The motor control ECU 202 includes a microcomputer 50, a drive circuit (inverter circuit) 41 controlled by the microcomputer 50 and supplying power to the electric motor 18, and a current detection circuit 42 for detecting the current flowing through the electric motor 18 (hereinafter referred to as "motor current I").

[0042] The microcomputer 50 includes a CPU and memory (ROM, RAM, nonvolatile memory, etc.), and functions as a plurality of functional processing sections by executing predetermined programs. The plurality of functional processing sections include an assist torque command value setting section 51, a manual steering command value calculation section 52, an integrated angle command value calculation section 53, an angle control section 54, a torque control section (current control section) 55, a selector switch 56, and an adder 57.

[0043] The assist torque command value setting unit 51 sets the assist torque command value T assist The assist torque command value setting unit 51 sets the steering torque T tb Based on this, the assist torque command value T assist Set the steering torque T tb Assist torque command value T assist An example of the configuration is shown in Figure 3.

[0044] Assist torque command value T assistis 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. assist is the steering torque T tb The steering torque T tb The assist torque command value T assist is the steering torque T tb The larger the absolute value of the assist torque command value T assist is input to the first input terminal of the changeover switch 56.

[0045] The assist torque command value setting unit 51 also takes into consideration the vehicle speed detected by a vehicle speed sensor (not shown) to determine the assist torque command value T assist In this case, the assist torque command value T assist is the steering torque T tb The absolute value of the y-axis is set to be larger as the absolute value of the y-axis increases, and the absolute value of the y-axis is set to be smaller as the vehicle speed increases.

[0046] The assist torque command value setting unit 51 sets the steering torque T tb is multiplied by a preset constant to obtain the assist torque command value T assist may be calculated.

[0047] When the driver operates the steering wheel 2, the manual steering command value calculation unit 52 calculates the steering angle (more precisely, the rotation angle of the pinion shaft 13) according to the steering wheel operation as a manual steering command value θ md,cmd The manual steering command value calculation unit 52 is provided to set the steering torque T tb and the assist torque command value T set by the assist torque command value setting unit 51. assist and the manual steering command value θ md,cmd The manual steering command value calculation unit 52 will be described in detail later.

[0048] The integrated angle command value calculation unit 53 calculates the automatic steering command value θ set by the host ECU 201. ad,cmd , manual steering command value θ md,cmd The integrated angle command value θ sint,cmd Calculate the following.

[0049] The angle control unit 54 calculates the integrated angle command value θ sint,cmd Based on this, the integrated angle command value θ sint,cmd The integrated motor torque command value T mint,cmd Calculate the integrated motor torque command value T mint,cmd is input to the second input terminal of the changeover switch 56. The integrated motor torque command value T mint is an example of the "integrated torque command value" in the present invention. Details of the angle control unit 54 will be described later.

[0050] The changeover switch 56 is connected to the operation mode signal S dr,mode The assist torque command value T assist and the integrated motor torque command value T mint,cmd One of these is the first motor torque command value T m1,cmd Specifically, when the driving mode is the driving assistance mode, the changeover switch 56 outputs the integrated motor torque command value T mint,cmd is the first motor torque command value T m1,cmd The first motor torque command value T m1,cmd is provided to the adder 57.

[0051] On the other hand, when the operation mode is the normal mode, the changeover switch 56 changes the assist torque command value T assist is the first motor torque command value T m1,cmd The first motor torque command value T m1cmd is provided to the adder 57.

[0052] Vibration torque command value T wa.cmd If the first motor torque command value T m1,cmd The final motor torque command value T m,cmdThe vibration torque command value T wa.cmd is output, the adder 57 calculates the first motor torque command value T m1,cmd and the vibration torque command value T wa.cmd The sum of these values ​​is the final motor torque command value T m,cmd It is calculated as:

[0053] The torque control unit 55 controls the motor torque of the electric motor 18 to be equal to the motor torque command value T m,cmd The driving circuit 41 is driven so that the value approaches .

[0054] FIG. 4 is a block diagram showing the configuration of the angle control unit 54.

[0055] The angle control unit 54 calculates the integrated angle command value θ sint,cmd Based on this, the integrated motor torque command value T mint,cmd The angle control unit 54 includes a low-pass filter (LPF) 61, a feedback control unit 62, a feedforward control unit 63, a disturbance torque estimating unit 64, a torque adding unit 65, a disturbance torque compensating unit 66, a first reduction ratio dividing unit 67, a reduction ratio multiplying unit 68, a rotation angle calculating unit 69, and a second reduction ratio dividing unit 70.

[0056] The reduction ratio multiplication unit 68 multiplies the first motor torque command value T m1,cmd is multiplied by the reduction ratio N of the reducer 19 to obtain the first motor torque command value T m1,cmd The pinion shaft torque command value N·T acting on the pinion shaft 13 (worm wheel 21) m1,cmd Convert to.

[0057] The rotation angle calculation unit 69 calculates the rotor rotation angle θ of the electric motor 18 based on the output signal of the rotation angle sensor 23. m The second reduction ratio division unit 70 calculates the rotor rotation angle θ calculated by the rotation angle calculation unit 69. m By dividing by the reduction ratio N, the rotor rotation angle θ m The rotation angle (actual steering angle) θ of the pinion shaft 13 p Convert to.

[0058] The low-pass filter 61 calculates the integrated angle command value θ sint,cmd The integrated angle command value θ after low-pass filtering is sin,cmd is provided to the feedback control section 62 and the feedforward control section 63.

[0059] The feedback control unit 62 calculates the steering angle estimated value ^θ calculated by the disturbance torque estimating unit 64. p is the integrated angle command value θ after low-pass filtering. sin,cmd 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 sin,cmd and the estimated steering angle ^θ p Deviation Δθ(=θ sin,cmd -^θ p ) is calculated. The angle deviation calculation unit 62A calculates the integrated angle command value θ sin and the steering angle θ calculated by the second reduction ratio division unit 70. p deviation from (θ sin,cmd -θ p ) may be calculated as the angle deviation Δθ.

[0060] The PD control unit 62B performs a PD calculation (proportional differential calculation) on the angle deviation Δθ calculated by the angle deviation calculation unit 62A, thereby obtaining a feedback control torque T fb Calculate the feedback control torque T fb is given to the torque adder 65.

[0061] 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 sin,cmd By taking the second derivative, the target angular acceleration d 2 θ sin,cmd / dt 2Calculate the following.

[0062] The inertia multiplication unit 63B multiplies the target angular acceleration d calculated by the angular acceleration calculation unit 63A by 2 θ sin,cmd / dt 2 is multiplied by the inertia J of the electric power steering system 1 to obtain the feedforward control torque T ff (=J·d 2 θ sin,cmd / dt 2 The inertia J can be calculated from, for example, a physical model 121 (see FIG. 5) of the electric power steering system 1, which will be described later. The feedforward control torque T ff is given to the torque adder 65 as an inertia compensation value.

[0063] The torque adder 65 calculates the feedback control torque T fb to the feedforward control torque T ff By adding fb +T ff ) is calculated.

[0064] The disturbance torque estimating unit 64 is provided to estimate a nonlinear torque (disturbance torque: torque other than motor torque) that occurs as a disturbance in the plant (the object to be controlled by the electric motor 18). The disturbance torque estimating unit 64 estimates the pinion shaft torque command value N·T m1,cmd and steering angle θ p Based on this, the disturbance torque (disturbance load) T lc , steering angle θ p and steering angle differential value (angular velocity) dθ p / dt is estimated. lc , steering angle θ p and steering angle differential value (angular velocity) dθ p / dt estimates, respectively, lc , ^θ p and d^θ p The disturbance torque estimating section 64 will be described in detail later.

[0065] 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, and is also given to the manual steering command value calculator 52 (see FIG. 2). The steering angle estimated value ^θ calculated by the disturbance torque estimator 64 p is given to the angle deviation calculation unit 62A.

[0066] The disturbance torque compensator 66 calculates the basic torque command value (T fb +T ff ) to the estimated disturbance torque ^T lc By subtracting pint,cmd (=T fb +T ff -^T lc ) is calculated. As a result, the integrated steering torque command value T pint,cmd (torque command value for the pinion shaft 13) is obtained.

[0067] Integrated steering torque command value T pint,cmd is given to a first reduction ratio division unit 67. The first reduction ratio division unit 67 calculates the integrated steering torque command value T pint,cmd By dividing by the reduction ratio N, the integrated motor torque command value T mint,cmd This integrated motor torque command value T mint,cmd is given to the changeover switch 56 (see FIG. 2).

[0068] The disturbance torque estimation unit 64 will be described in detail. The disturbance torque estimation unit 64 uses, for example, a physical model 121 of the electric power steering system 1 shown in FIG. 5 to estimate the disturbance torque T lc , steering angle θ p and angular velocity dθ p It consists of a disturbance observer that estimates / dt.

[0069] This physical model 121 includes a plant (an example of a motor-driven object) 122 including an output shaft 9 and a worm wheel 21 fixed to the output shaft 9. The plant 122 receives a steering torque T tbis applied, and a road reaction torque T rl is given.

[0070] Furthermore, the plant 122 receives a pinion shaft torque command value N·T via the worm gear 20. m1,cmd is given, and friction torque T f is given.

[0071] When the inertia of the plant 122 is J, the equation of motion for the inertia of the physical model 121 is expressed by the following equation (3).

[0072]

number

[0073] d 2 θ p / dt 2 is the angular acceleration of the plant 122. N is the reduction ratio of the reducer 19. T lc represents a disturbance torque other than the motor torque applied to the plant 122. In this embodiment, the disturbance torque T lc is the steering torque T tb and road reaction torque T rl and friction torque T f However, in reality, the disturbance torque T lc includes torques other than these.

[0074] The state equation for the physical model 121 in FIG. 5 is expressed by the following equation (4).

[0075]

number

[0076] In the above formula (4), x is a state variable vector, u1 is a known input vector, u2 is an unknown input vector, and y is an output vector (measured value). Also, in the above formula (4), A is a system matrix, B1 is a first input matrix, B2 is a second input matrix, C is an output matrix, and D is a direct feedthrough matrix.

[0077] 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).

[0078]

number

[0079] In the formula (5), x e is the state variable vector of the extended system and is expressed by the following equation (6).

[0080]

number

[0081] In the formula (5), A e is the system matrix of the extended system, B e is the known input matrix of the extended system, and Ce is the output matrix of the extended system.

[0082] From the extended state equation of the above formula (5), a disturbance observer (extended state observer) expressed by the following formula (7) is constructed.

[0083]

number

[0084] In equation (7), ^x e x e represents the estimated value of . Also, L is the observer gain. Also, ^y represents the estimated value of y. ^x e is expressed by the following equation (8).

[0085]

number

[0086] In equation (8), ^θ p is θ p is an estimate of ^T lc is T lc is an estimate of

[0087] The disturbance torque estimation unit 64 calculates the state variable vector ^x based on the equation (7). e Calculate the following.

[0088] FIG. 6 is a block diagram showing the configuration of the disturbance torque estimating unit 64.

[0089] 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.

[0090] The pinion shaft torque command value N·T calculated by the reduction ratio multiplication unit 68 (see FIG. 4) m1,cmd is given to the input vector input unit 81. The input vector input unit 81 outputs the input vector u1.

[0091] 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.

[0092] 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.

[0093] The first adder 83 calculates the steering angle θ calculated by the second reduction ratio divider 70 (see FIG. 4). p From the output vector (measurement value) y, which is e ^x e ) is subtracted from the output vector y. That is, the first adder 83 subtracts the output vector estimate ^y(=C e ^x e The gain multiplication unit 84 multiplies the output (y-^y) of the first addition unit 83 by the observer gain L (see equation (7) above).

[0094] 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 , the steering angle estimated value ^θ and the angular velocity estimated value d^θ / dt are calculated.

[0095] 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).

[0096]

number

[0097] The input to a typical disturbance observer is J d 2 θ p / dt 2 and N.T. m1,cmd and the steering angle θ p Since the second-order differential value of is used, it is significantly affected by noise from the rotation angle sensor 23. In contrast, the extended state observer of the above-described embodiment estimates the disturbance torque in an integral manner, so that it is possible to reduce the influence of noise due to differentiation.

[0098] 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.

[0099] FIG. 7 is a schematic diagram showing the configuration of the torque control unit 55.

[0100] The torque control unit 55 (see FIG. 2) includes a motor current command value calculation unit 91, a current deviation calculation unit 92, a PI control unit 93, and a PWM (Pulse Width Modulation) control unit 94.

[0101] The motor current command value calculation unit 91 calculates the motor torque command value T m,cmd The torque constant K of the electric motor 18 t By dividing by, the motor current command value I m,cmd Calculate the following.

[0102] The current deviation calculation unit 92 calculates the motor current command value I obtained by the motor current command value calculation unit 91. m,cmd and the motor current I detected by the current detection circuit 42. m Deviation ΔI (=I m,cmd -I m ) is calculated.

[0103] The PI control unit 93 performs a PI calculation (proportional integral calculation) on the current deviation ΔI calculated by the current deviation calculation unit 92, thereby controlling the motor current I m The motor current command value I m,cmdThe 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 41. As a result, power corresponding to the drive command value is supplied to the electric motor 18.

[0104] The manual steering command value calculation unit 52 will be described in detail below.

[0105] FIG. 8 is a block diagram showing the configuration of the manual steering command value calculation unit 52.

[0106] The manual steering command value calculation unit 52 includes a high-pass filter 101 , a determination unit 102 , a first dead-band processing unit 103 , a second dead-band processing unit 104 , and a command value calculation unit 105 .

[0107] The high-pass filter 101 is a filter for detecting the disturbance torque estimated value ^T lc High frequency components of HPF(^T lc In this embodiment, the disturbance torque estimate ^T lc High frequency components of HPF(^T lc ) is an example of "road surface information including at least information related to road surface reaction torque" in the present invention.

[0108] The first dead zone processing unit 103 receives the steering torque T tb As shown in FIG. 9, the first dead zone processing unit 103 calculates the steering torque T tb is within the range of -W1 / 2 or more and W1 / 2 or less (first dead band region), zero is set as the steering torque T after the first dead band processing. tb,de Output as

[0109] 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 [Ttb -(W1 / 2)] is the steering torque T after the first dead zone processing. tb,de Output as

[0110] The second dead zone processing unit 104 receives the assist torque T assist When the second dead zone width is W2, the second dead zone processing unit 104 calculates the assist torque T assist is within the range of -W2 / 2 or more and W2 / 2 or less (second dead band area), zero is set to the assist torque T after the second dead band processing. assist,de Output as

[0111] Assist torque T assist In the region where is smaller than −W2 / 2, the second dead band processing unit 104 calculates [T assist +(W2 / 2)] is the assist torque T after the second dead band processing. assist,de The assist torque T assist In the region where [T assist -(W1 / 2)] is the assist torque T after the second dead band processing. assist,de Output as

[0112] The determination unit 102 outputs the warning mode signal S wa,mode , steering torque T tb and the assist torque command value T assist Based on this, the manual steering command value θ md,cmd The disturbance torque estimate ^T lc High frequency components of HPF(^T lc ) is used. Then, the determining unit 102 determines whether or not to use the manual steering command value θ md,cmd The disturbance torque estimate ^T lc High frequency components of HPF(^T lc ) is used, the variable T x to HPF(^T lc ) and set the manual steering command value θ md,cmd The disturbance torque estimate ^T lc High frequency components of HPF(^T lc ) is not used, the variable T xSet to 0.

[0113] 11A and 11B are flowcharts showing the procedure of the determination process executed by the determination unit 102 in the driving assistance mode.

[0114] The determination process shown in steps S4 to S18 in FIGS. 11A and 11B is repeatedly executed at predetermined calculation intervals Δt.

[0115] Referring to FIG. 11A, when the power is turned on (step S1), the determination unit 102 sets the count value k to 0 (step S2), and also sets the latch flag T x_switch_latch is set to 0 (step S3). Then, the determination unit 102 proceeds to step S4.

[0116] In step S4, the determination unit 102 determines the steering torque T tb Absolute value of |T tb | is outside the first dead zone or the assist torque command value T assist Absolute value of |T assist It is determined whether or not the determination condition that |T is outside the second dead zone is satisfied. tb The first condition is |>(W1 / 2) and |T assist On the other hand, if neither the first condition nor the second condition is satisfied, that is, if the steering torque T tb is within the first dead zone and the assist torque command value T assist is within the second dead zone, the determining unit 102 determines that the determination condition is not satisfied.

[0117] In step S4, if it is determined that the determination condition is satisfied (step S4: YES), the determination unit 102 sets the switching flag T x_switch The determination unit 102 also sets the latch flag T x_switch_latchis set to 1 (step S6). Then, the determination unit 102 sets the count value k to 0 (step S7), and then proceeds to step S14.

[0118] In step S4, if it is determined that the determination condition is not satisfied (step S4: NO), as shown in FIG. 11B, the determination unit 102 sets the switching flag T x_switch is set to 0 (step S8).

[0119] Next, the determination unit 102 sets the latch flag T x_switch_latch It is determined whether or not the value is set to 1 (step S9).

[0120] Latch Flag T x_switch_latch If it is set to 0 (step S9: NO), the decision unit 102 proceeds to step S14.

[0121] In step S9, the latch flag T x_switch_latch If it is determined that the count value k is set to 1 (step S9: YES), the determination unit 102 increments the count value k by 1 (step S10). _th In other words, it is determined whether the time from when the count value k was set to 0 in the most recent step S7 to the present time is greater than (k _th × Δt) s It is determined whether the predetermined time T s An example of the setting will be described later.

[0122] The count value k is a predetermined threshold k _th If it is greater than (step S11: YES), the decision unit 102 sets the latch flag T x_switch_latch After setting it to 0 (step S12), the process proceeds to step S14.

[0123] In step S11, the count value k is equal to or smaller than a predetermined threshold value k _thIf it is determined that the value is equal to or less than the latch flag T x_switch_latch After setting it to 1 (step S13), the process proceeds to step S14.

[0124] Returning to FIG. 11A, in step S14, the determination unit 102 determines whether the warning mode signal S wa,mode If the device is in the warning mode (step S14: YES), the determination unit 102 proceeds to step S16.

[0125] In step S14, if it is determined that the warning mode is not in effect (step S14: NO), the determination unit 102 sets the latch flag T x_switch_latch , switch flag T x_switch (Step S15). Then, the determination unit 102 proceeds to Step S16.

[0126] In step S16, the determination unit 102 sets the latch flag T x_switch_latch Determine whether the latch flag T is 1. x_switch_latch If T is 1 (step S16: YES), the decision unit 102 x to HPF(^T lc ) (step S17). Then, the determination unit 102 returns to step S4.

[0127] In step S16, the latch flag T x_switch_latch If it is determined that T is 0 (step S16: NO), the determination unit 102 x Then, the determination unit 102 returns to step S4.

[0128] Predetermined time T s An example of setting the predetermined time T will be described. For example, when the vibration waveform during the warning mode is a waveform as shown in FIG. s In the warning mode shown in Fig. 12, the target vibration waveform consisting of a 20 Hz sine wave is repeated for six periods, and then an interval time TA A set consists of three repetitions of the pattern.

[0129] Predetermined time T s is the interval time T A or more is preferable, and the interval time T A The time T is the time when one period of the target vibration waveform is added to B More preferably, the predetermined time T s is the total time T for one set of warning mode C It is preferable that:

[0130] In the warning mode of Figure 12, the period of the sine wave, which is the target vibration waveform, is T w If the time is 0.05 seconds, the predetermined time T s is 2×T w (=0.1 seconds) or more is preferable, and 3×T w (=0.15 seconds) or more is more preferable. s is 24×T w (=1.2 seconds) or less is preferable.

[0131] According to the determination process of FIG. 11, the steering torque T tb and the assist torque command value T assist If at least one of the above is outside the dead zone (if the judgment conditions are met), T x_switch = 1, and T x_switch_latch In this case, even if the warning mode is not active, T is set to 1 and k is set to 0 (see steps S5, S6, and S7). x_switch_latch = 1, so regardless of whether the system is in warning mode or not, T x =HPF(^T lc ) (see steps S16 and S17).

[0132] On the other hand, the steering torque T tb and the assist torque command value T assist If both are in the insensitive area (if the judgment condition is not met), T x_switch = 0 (see step S8). In this case, in step S9, Tx_switch_latch If it is determined that T = 0, even if the warning mode is not active, the T x_switch_latch = 0, regardless of whether the warning mode is active or not. x =0 (see steps S16 and S18).

[0133] In other words, the steering torque T tb and the assist torque command value T assist If at least one of the above is outside the insensitive area (if the judgment conditions are met), then in principle, T x =HPF(^T lc ) Steering torque T tb and the assist torque command value T assist If both are in the insensitive area (if the judgment conditions are not met), then in principle, T x =0.

[0134] In step S9, T x_switch_latch = 1, and the time elapsed since the count value k was reset in the most recent step S7 is equal to or exceeds the predetermined time T s If it is greater than T x_switch_latch In this case, even if the warning mode is not active, T is set to 0 in step S15. x_switch_latch = 0, regardless of whether the warning mode is active or not. x =0 (see steps S16 and S18).

[0135] In step S9, T x_switch_latch = 1, and the time elapsed since the count value k was reset in the most recent step S7 is equal to or exceeds the predetermined time T s If the condition is not met, T x_switch_latch = 1 (see step S13). In this case, if the warning mode is not active, the process in step S15 sets T x_switch_latch = 0, so T x = 0 (see steps S16 and S18). On the other hand, if the warning mode is active, the process of step S15 is not performed, and therefore T x =HPF(^Tlc ) (see steps S16 and S17).

[0136] That is, in the calculation cycle following the calculation cycle in which the count value k was set to 0 in step S7, if it is determined that the judgment condition is not satisfied and the state in which the judgment condition is not satisfied continues, the time elapsed since the count value k was set to 0 in step S7 is equal to or exceeds the predetermined time T s If it is within the time limit and in warning mode, T x =HPF(^T lc ) If the condition continues not to be met after that, T x =0.

[0137] This allows you to x =HPF(^T lc ) state and T x = 0 state is prevented from being repeated frequently.

[0138] The command value calculation unit 105 uses the reference EPS model to calculate the manual steering command value θ md,cmd The reference EPS model is a single-inertia model that includes the lower column.

[0139] Specifically, the command value calculation unit 105 calculates the manual steering command value θ by solving the differential equation of the following equation (10): md,cmd Calculate the following.

[0140] J md ·d 2 θ md,cmd / dt 2 =T tb,de +N·T assist,de -k1·θ md,cmd -c1(dθ md,cmd / dt)-T x …(10) In equation (10), J md is the inertia of the lower column, and T tb,de is the steering torque after the first dead zone processing, N is the reduction ratio of the reducer 19, and T assist,deis the assist torque after the second dead band processing, k1 is the spring constant, c1 is the viscous damping coefficient, and T x is a variable set by the determining unit 102. In this embodiment, the spring constant k1 and the viscous damping coefficient c1 are set in advance.

[0141] In the following, the steering torque T tb , assist torque command value T assist and warning mode signal S wa,mode Regardless of the T in Eq. (10), x as HPF(^T lc ) to obtain the manual steering command value θ md,cmd The motor control ECU that calculates the above will be referred to as a first comparative example.

[0142] In the first comparative example, even when the driver does not intervene in the steering during the driving assistance mode, the HPF(^T lc ) is generated, the problem is that the vehicle does not track the target route well.

[0143] Therefore, the steering torque T tb and the assist torque command value T assist When at least one of the above is outside the insensitive region, T in Eq. (10) x to HPF(^T lc ) and the steering torque T tb and the assist torque command value T assist When both are in the insensitive region, T in Eq. (10) x It is possible to set 0 to T x Using this, the manual steering command value θ md,cmd The motor control ECU in which the above is calculated will be referred to as a second comparative example.

[0144] That is, in the second comparative example, if the determination in step S4 of FIG. 11 is affirmative (YES), T x to HPF(^T lc ) is set, and if the determination in step S4 of FIG. 11 is negative (NO), T x is set to 0. In other words, Tx_switch If =1, then T x to HPF(^T lc ) is set, and T x_switch If =1, then T x is set to 0.

[0145] In the second comparative example, when the driver does not intervene in the steering during the driving assistance mode (T tb and T assist If both are in the insensitive region, the HPF(^T lc ) is no longer generated, the ability to follow the target driving route is improved compared to the first comparative example.

[0146] However, in the warning mode, the vibration torque command value T wa.cmd The steering torque T tb and the assist torque command value T assist is outside the insensitive region, and the steering torque T tb and the assist torque command value T assist As a result, the manual steering command value θ md,cmd changes in a short cycle, causing the steering angle to move excessively.

[0147] In this embodiment, when the warning mode is not being executed, the steering torque T tb and the assist torque command value T assist If at least one of these is outside the insensitive region, T x to HPF(^T lc ) is set, and the steering torque T tb and the assist torque command value T assist When both are in the insensitive region, T x is set to 0. This improves the ability to follow the target driving route compared to the first comparative example.

[0148] In this embodiment, during the warning mode, the steering torque T tb and the assist torque command value T assistFrom the first state in which at least one of the above is outside the insensitive region, the steering torque T tb and the assist torque command value T assist When the state changes to the second state in which both of the first and second states are in the insensitive region, a predetermined time T s Until time has passed, T x to HPF(^T lc ) remains set. This allows you to x =HPF(^T lc ) state and T x This prevents the state of the manual steering command value θ from being frequently repeated during the warning mode. md,cmd Since it is possible to suppress short-period changes in the steering angle, it is possible to suppress excessive movement of the steering angle during the warning mode.

[0149] Although the embodiment and modifications of the present invention have been described above, the present invention can also be embodied in other forms.

[0150] In the above-described embodiment, in step S17 of FIG. 11A, the determination unit 102 determines whether T x to HPF(^T lc However, in step S17 of FIG. 11A, the determination unit 102 determines that T x , the estimated disturbance value ^T lc may be set.

[0151] In step S17 of FIG. 11A, the determination unit 102 determines whether T x , the estimated disturbance value ^T lc to steering torque T tb The value obtained by subtracting (^T lc -T tb ) high frequency components of HPF(^T lc -T tb ) can be set. HPF(^T lc -T tb ) is (^T lc -T tb ) can be obtained by performing a high-pass filter process.

[0152] In step S17 of FIG. 11A, the determination unit 102 determines whether T x , the estimated disturbance value ^T lc to steering torque T tb The value obtained by subtracting (^T lc -T tb ) may be set.

[0153] In step S17 of FIG. 11A, the determination unit 102 determines whether T x , the estimated disturbance value ^T lc to steering torque T tb and friction torque T f The value obtained by subtracting (^T lc -T tb -T f ) high frequency components of HPF(^T lc -T tb -T f ) can be set. HPF(^T lc -T tb -T f ) is (^T lc -T tb -T f ) can be obtained by high-pass filtering. f can be estimated using, for example, a friction model that estimates the friction occurring in the reducer 19.

[0154] In step S17 of FIG. 11A, the determination unit 102 determines whether T x , the estimated disturbance value ^T lc to steering torque T tb and friction torque T f The value obtained by subtracting (^T lc -T tb -T f ) may be set.

[0155] In addition, instead of the second dead zone processing unit 104, the steering torque T tbIn this case, the dead zone width of the third dead zone processing unit 103 may be the same as or different from the dead zone width W1 of the second dead zone processing unit 103. In this case, in step S4 of FIG. 11A, the determination unit 102 determines whether the steering torque T tb Absolute value of |T tb | is outside the first dead zone or the steering torque T tb Absolute value of |T tb is outside the dead-band region of the third dead-band processing unit.

[0156] In addition, instead of the first dead zone processing unit 103 and the second dead zone processing unit 104, a common steering torque T tb In this case, in step S4 of FIG. 11A, the determination unit 102 determines whether the steering torque T tb Absolute value of |T tb is outside the dead-band region of the fourth dead-band processing unit.

[0157] In the above embodiment, the angle control unit 54 (see FIG. 4) includes the feedforward control unit 63, but the feedforward control unit 63 may be omitted. In this case, the feedback control torque T calculated by the feedback control unit 62 is fb is the basic target torque.

[0158] In the above embodiment, the present invention is applied to the motor control of a column-type EPS, but the present invention can also be applied to the motor control of an EPS other than a column-type EPS.The present invention can also be applied to the control of an electric motor for steering angle control in a steer-by-wire system.

[0159] 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]

[0160] 1... electric power steering device, 3... steered wheels, 4... steering mechanism, 18... electric motor, 51... assist torque command value setting section, 52... manual steering command value calculation section, 53... integrated angle command value calculation section, 54... angle control section, 55... torque control section, 56... switching section, 57... addition section, 61... low-pass filter (LPF), 62... feedback control section, 63... feedforward control section, 64... disturbance torque estimating section, 65... torque addition section, 66... ​​disturbance torque compensation section, 101... high-pass filter, 102... determination section, 103... first dead-band processing section, 104... second dead-band processing section, 105... command value calculation section

Claims

1. A motor control device for driving and controlling an electric motor for steering angle control, an assist torque command value calculation unit that calculates an assist torque command value using the steering torque; a manual steering command value calculation unit that calculates 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 the electric motor based on the integrated angle command value; where the steering torque input to the manual steering command value calculation unit, the assist torque command value input to the manual steering command value calculation unit, and the steering torque input to the assist torque command value calculation unit are defined as input torques, a dead band processing unit is provided for at least one of the input torques; a warning vibration applying unit that applies a warning vibration torque as a component of a motor torque command value of the electric motor, the manual steering command value calculation unit is configured to use road surface information including information about a road surface reaction torque in the calculation of the manual steering command value when a first condition is satisfied that at least one of the input torques for which the dead zone processing unit is provided is outside a dead zone range, and not to use the road surface information in the calculation of the manual steering command value when the first condition is not satisfied, The motor control device, when the warning vibration torque is applied, the manual steering command value calculation unit uses the road surface information in calculating the manual steering command value for a certain period from the point in time when the state changes from satisfying the first condition to not satisfying the first condition.

2. 2. The motor control device according to claim 1, wherein the dead zone processing unit includes a first dead zone processing unit provided for the steering torque input to the manual steering command value calculation unit, and a second dead zone processing unit provided for the assist torque command value input to the manual steering command value calculation unit.

3. 3. The motor control device according to claim 1, wherein the road surface information is calculated based on an integrated torque command value corresponding to the integrated angle command value and a steering angle, and is a high-frequency component of an estimated value of disturbance torque applied to a steering shaft.

4. 4. The motor control device according to claim 1, wherein the warning vibration providing unit is configured to output a vibration torque command value corresponding to a target warning vibration waveform, and the vibration torque command value is added to an integrated torque command value corresponding to the integrated angle command value.

5. 4. The motor control device according to claim 1, wherein the warning vibration providing unit is configured to output a vibration angle command value corresponding to a target warning vibration waveform, and the vibration angle command value is added to the integrated angle command value.

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