Control device, electric power steering device, and control method

Abstract

A control device, an electric power steering device, and a control method. The control device includes: a first assist control unit capable of executing lane maintenance control and generating a first input value; a second assist control unit that generates a second input value on the basis of the steering input value; and an interference sensitivity control unit to which a command value calculated on the basis of the first and second input values multiplied by the first and second gains is input. When the first gain is set as K1 and the second gain is set as K2, K1 = 1-K2 is satisfied. The disturbance sensitivity control unit has a first model tracking control unit that generates a correction value for correcting the command value on the basis of the output of the control target and the first nominal model. The first model tracking control unit restricts the transfer function of the control object to the transfer function of the first nominal model in a frequency band in which the complementary sensitivity gain of the complementary sensitivity function with respect to the modeling error between the control object and the first nominal model is approximately 1. The complementary sensitivity function includes a variable parameter that varies according to the second gain.

Description

Technical Field

[0001] The invention relates to a control device, an electric power steering device and a control method. Background Art

[0002] Conventionally, there is known an electric power steering system mounted on a vehicle (for example, Patent Document 1).

[0003] Patent Document 1: Japanese Patent Application Publication No. 2018-183046

[0004] The electric power steering system as described above may have a control device capable of executing lane keeping control, for example. Lane keeping control is a control that maintains the vehicle in the lane by providing a driving force to the steering mechanism through a motor when the vehicle is about to leave the lane. If the control amount of lane keeping control becomes larger, the discomfort felt by the steersman from the steering wheel becomes larger. On the other hand, if the control amount of lane keeping control is reduced in order to reduce the discomfort felt by the steersman, it is difficult to fully control the vehicle through lane keeping control, and there is a problem of reduced accuracy in maintaining the vehicle in the lane. Summary of the invention

[0005] In view of the above circumstances, one object of the present invention is to provide a control device and a control method that can improve the accuracy of lane keeping control while reducing the discomfort felt by the steersman from the steering wheel, and an electric power steering device having such a control device.

[0006] One embodiment of the present invention is a control device that controls a steering mechanism mounted on a vehicle, wherein the control device includes: a first auxiliary control unit that can perform lane keeping control to keep the vehicle in a lane and generate a first input value; a second auxiliary control unit that generates a second input value based on a steering input value input from a steering wheel of the vehicle; and a disturbance sensitivity control unit that receives an instruction value calculated based on the first input value multiplied by a first gain and the second input value multiplied by a second gain. The first gain and the second gain are variable values. When the first gain is set to K1 and the second gain is set to K2, K1=1-K2 holds. The disturbance sensitivity control unit includes a first model tracking control unit that generates a correction value for correcting the instruction value based on an output of a control object including a motor provided in the steering mechanism and a first nominal model based on the structure of the control object. The first model tracking control unit is configured to constrain the transfer function of the controlled object to the transfer function of the first nominal model in a frequency band in which a gain in a gain characteristic of a complementary sensitivity function with respect to a modeled error between the controlled object and the first nominal model, that is, a complementary sensitivity gain, is approximately 1. The complementary sensitivity function includes a variable parameter that changes according to the second gain.

[0007] One aspect of the present invention is an electric power steering device including the above-mentioned control device and the steering mechanism.

[0008] One embodiment of the present invention is a control method for controlling a steering mechanism mounted on a vehicle, wherein the control method includes the following steps: performing lane keeping control for maintaining the vehicle in a lane; generating a first input value by the lane keeping control; generating a second input value based on a steering input value input from a steering wheel of the vehicle; calculating a command value based on the first input value multiplied by a first gain and the second input value multiplied by a second gain; performing model following control for generating a correction value for correcting the command value based on an output of a control object including a motor provided in the steering mechanism and a first nominal model based on a structure of the control object; and constraining a transfer function of the control object to a transfer function of the first nominal model in a frequency band where a gain in a gain characteristic of a complementary sensitivity function with respect to a modeled error between the control object and the first nominal model, i.e., a complementary sensitivity gain, is approximately 1 by the model following control. The first gain and the second gain are variable values. When the first gain is K1 and the second gain is K2, K1=1-K2 holds. The complementary sensitivity function includes a variable parameter that changes according to the second gain.

[0009] According to one aspect of the present invention, it is possible to improve the accuracy of lane keeping control while reducing the discomfort felt by the steersman from the steering wheel. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] Figure 1 It is a diagram schematically showing the electric power steering device in the first embodiment.

[0011] Figure 2 This is a block diagram showing the configuration of the control device in the first embodiment.

[0012] Figure 3 This is a diagram schematically showing a state in which a vehicle equipped with the lane keeping system according to the first embodiment travels on a lane.

[0013] Figure 4 This is a block diagram showing the configuration of the lane keeping system in the first embodiment.

[0014] Figure 5 This is a block diagram showing the configuration of an imaging device and a first assist control unit in the first embodiment.

[0015] Figure 6 It is a diagram for explaining the lane keeping control in the first embodiment.

[0016] Figure 7 It is a block diagram showing the configuration of the lane keeping control unit in the first embodiment.

[0017] Figure 8 This is a block diagram showing the configuration of the lateral deviation control unit in the first embodiment.

[0018] Fig. 9 1 is a Bode diagram showing an example of the gain of the transfer function of the lateral offset adjustment unit and the gain of the transfer function of the yaw rate adjustment unit in the first embodiment.

[0019] Fig.10 This is a block diagram showing the configuration of the yaw rate control unit in the first embodiment.

[0020] Fig.11 This is a block diagram showing the configuration of the second assist control unit in the first embodiment.

[0021] Fig.12 This is a graph showing an example of the relationship between the input torque and the assist torque in the first embodiment.

[0022] Fig.13 This is a block diagram showing the configuration of the vehicle stabilization control unit in the first embodiment.

[0023] Fig.14 : is a Bode diagram showing the gain of the transfer function of the second nominal model in the first embodiment.

[0024] Fig.15 It is a block diagram showing the configuration of the second state feedback unit in the first embodiment.

[0025] Fig.16 This is a block diagram showing the configuration of a disturbance sensitivity control unit in the first embodiment.

[0026] Fig.17 This is a graph illustrating the gain characteristic of the complementary sensitivity function of the first model tracking control unit in the first embodiment and the gain characteristic of the inverse of the modeling error between the transfer function of the first controlled object and the transfer function of the first nominal model.

[0027] Fig.18 This is a graph showing an example of the relationship between the steering angle and the self-aligning torque.

[0028] Fig.19 It is a block diagram showing the configuration of a lane keeping system in the second embodiment.

[0029] Fig. 20 This is a block diagram showing the configuration of a yaw rate control unit in the third embodiment.

[0030] Description of symbols

[0031] 100, 100A, 100B: control device; 210: first auxiliary control unit; 211: vehicle state calculation unit; 213, 1213: yaw rate control unit; 213b: yaw rate adjustment unit; 213c: yaw rate phase adjustment unit; 214: lateral deviation control unit; 214b: lateral deviation adjustment unit; 220, 220A: second auxiliary control unit; 230: first model tracking control unit; 240, 240A: vehicle stabilization control unit; 241: second model tracking control unit; 290: interference sensitivity control unit; 400: camera device; 5 21: steering wheel; 524a: input shaft; 524b: output shaft; 529A, 529B: tire; 530: steering mechanism; 543: motor; 546: torsion bar; 560: first control object (control object); 1000: electric power steering device; fb1: first frequency band; fb2: second frequency band; GT: complementary sensitivity gain; K1: first gain; K2: second gain; L: lane; m: variable parameter; NM1: first nominal model; NM2: second nominal model; T(0): steady-state gain; T(s): complementary sensitivity function; T ad : Input torque; T ass : Assist torque; T f1 : The first correction torque (correction value); T LKA : 1st command torque (1st input value); T r : The second command torque (the second input value); T rL1 : Command torque (command value); T SAT : automatic return torque; V: vehicle; y of : lateral deviation; γ: yaw rate; γ r , γ r1 , γ r2 , γ r3 : yaw rate target value; θ s : steering angle; θ t : Actual rudder angle. DETAILED DESCRIPTION

[0032] <First embodiment>

[0033] Figure 1 The electric power steering device 1000 of the present embodiment shown in FIG. Figure 1 As shown in FIG. 1 , the electric power steering device 1000 includes a steering mechanism 530 and a control device 100. The steering mechanism 530 includes a steering mechanism portion 520 and an assist mechanism portion 540. The electric power steering device 1000 generates an assist torque by controlling the assist mechanism portion 540 by the control device 100. The assist torque is used to generate an assist torque to the steering torque T generated in the steering mechanism portion 520 when the driver of the vehicle V steers the steering wheel 521.h The assist torque reduces the operation burden of the driver when the driver operates the steering wheel 521. The driver of the vehicle V is a steerer who steers the steering wheel 521 of the vehicle V.

[0034] The steering mechanism 520 includes a steering wheel 521, a steering shaft 522, universal joints 523A and 523B, an input shaft 524a, an output shaft 524b, a rack-and-pinion mechanism 525, a rack shaft 526, left and right ball joints 552A and 552B, tie rods 527A and 527B, knuckles 528A and 528B, and left and right tires 529A and 529B. That is, the steering mechanism 530 includes a steering wheel 521, a steering shaft 522, universal joints 523A and 523B, an input shaft 524a, an output shaft 524b, a rack-and-pinion mechanism 525, a rack shaft 526, left and right ball joints 552A and 552B, tie rods 527A and 527B, knuckles 528A and 528B, and left and right tires 529A and 529B.

[0035] The steering shaft 522 is a shaft extending from the steering wheel 521 steered by the helmsman. One end of the input shaft 524a is connected to the end of the steering shaft 522 on the side opposite to the side connected to the steering wheel 521 via universal couplings 523A and 523B. Thus, the steering wheel 521 is connected to the input shaft 524a via universal couplings 523A and 523B and the steering shaft 522. The output shaft 524b is connected to the input shaft 524a via a torsion bar 546 described later. In more detail, one end of the output shaft 524b is connected to the other end of the input shaft 524a via the torsion bar 546. The other end of the output shaft 524b is connected to the rack shaft 526 via a gear rack mechanism 525.

[0036] The input shaft 524a and the output shaft 524b are coaxially arranged. The input shaft 524a and the output shaft 524b are rotatable about the same central axis. The input shaft 524a and the output shaft 524b are rotatable relative to each other within a range within which a torsion bar 546 described later can twist.

[0037] The auxiliary mechanism unit 540 includes a steering torque sensor 541, a steering angle sensor 542, a motor 543, a speed reduction mechanism 544, an inverter 545, and a torsion bar 546. That is, the steering mechanism 530 includes a steering torque sensor 541, a steering angle sensor 542, a motor 543, a speed reduction mechanism 544, an inverter 545, and a torsion bar 546. The torsion bar 546 connects the input shaft 524a and the output shaft 524b. The torsion bar 546 is coaxially arranged with the input shaft 524a and the output shaft 524b. In the following description, an imaginary axis passing through the common central axis of the input shaft 524a, the output shaft 524b, and the torsion bar 546 is referred to as a rotation axis R. The torsion bar 546 can be twisted around the rotation axis R.

[0038] The steering torque sensor 541 detects the amount of torsion of the torsion bar 546 around the rotation axis R to detect the steering torque T in the steering mechanism 520. h . Steering torque T h is the torsion bar torque generated by the torsion bar 546, and is the torsion moment about the rotation axis R. The steering angle sensor 542 can detect the rotation angle θ of the input shaft 524a about the rotation axis R. a The rotation angle θ of the input shaft 524a is a The steering angle θ of the steering wheel 521 h That is, the steering angle sensor 542 can detect the rotation angle θ of the input shaft 524a. a To detect the steering angle θ of the steering wheel 521 h The rotation angle θ of the output shaft 524b can be detected by the steering torque sensor 541 and the steering angle sensor 542. b The rotation angle θ of the output shaft 524b b is the steering angle θ s .

[0039] The inverter 545 converts the DC power into three-phase AC power of pseudo-sine waves of U phase, V phase and W phase according to the motor drive signal input from the control device 100, and supplies it to the motor 543. The motor 543 is connected to the output shaft 524b via the reduction mechanism 544. The three-phase AC power is supplied to the motor 543 from the inverter 545. The motor 543 is, for example, an interior permanent magnet synchronous motor (IPMSM: Interior Permanent Magnet Synchronous Motor), a surface mounted permanent magnet synchronous motor (SPMSM: Surface mounted Permanent Magnet Synchronous Motor) or a switched reluctance motor (SRM: Switched Reluctance Motor). The motor 543 generates a steering torque T by being supplied with three-phase AC power by the inverter 545.h The motor 543 transmits the generated assist torque to the output shaft 524b via the speed reduction mechanism 544.

[0040] The control device 100 is a control device for controlling the steering mechanism 530 mounted on the vehicle V. In the present embodiment, the control device 100 can control the first control object 560. The first control object 560 is a control object including the motor 543 provided in the steering mechanism 530. In the present embodiment, the first control object 560 includes a steering mechanism 520, a torsion bar 546, a motor 543, and a speed reduction mechanism 544. Since the first control object 560 includes an input shaft 524a and an output shaft 524b that can rotate relative to each other via the torsion bar 546, the motion of the first control object 560 cannot be described by a simple motion equation of one inertial system. The first control object 560 changes between one inertial system and two inertial systems according to the strength with which the steersman holds the steering wheel 521. The harder the steersman holds the steering wheel 521, the closer the first control object 560 is to one inertial system. The weaker the driver grips the steering wheel 521, the closer the first control object 560 is to two inertial systems. Thus, the first control object 560 is composed of two inertial systems.

[0041] The control device 100 is electrically connected to the inverter 545. The control device 100 generates a motor drive signal based on detection signals detected by the steering torque sensor 541, the steering angle sensor 542, and the vehicle speed sensor 300 mounted on the vehicle V, and outputs it to the inverter 545. The control device 100 controls the first control object 560 by controlling the rotation of the motor 543 via the inverter 545. In more detail, the control device 100 controls the switching action of multiple switching elements possessed by the inverter 545. Specifically, the control device 100 generates a control signal for controlling the switching action of each switching element and outputs it to the inverter 545. Each switching element is, for example, a MOSFET (Metal-Oxide-Semiconductor Field-Effect Transistor). In the following description, the control signal for controlling the switching action of each switching element is referred to as a "gate control signal".

[0042] The control device 100 controls the steering torque T hThe torque command value is generated by, for example, controlling the torque of the motor 543 and the rotation speed of the motor 543 by vector control. Vector control is a method of decomposing the current flowing through the motor 543 into a current component that contributes to the generation of torque and a current component that contributes to the generation of magnetic flux, and independently controlling each current component that is perpendicular to each other. The control device 100 is not limited to vector control, and other closed-loop controls can also be performed. The rotation speed of the motor 543 is represented, for example, by the rotation speed of the rotor in 1 minute [rpm (revolutions per minute: revolutions / minute)] or the rotation speed of the rotor in 1 second [rps (revolutions per second: revolutions / second)].

[0043] In addition, the steering torque T can be directly input to the control device 100 from the steering torque sensor 541. h The steering torque T can also be calculated by the control device 100 based on the output value of the steering torque sensor 541. h The steering angle θ of the steering wheel 521 can be directly input to the control device 100 from the steering angle sensor 542. h The control device 100 can also calculate the steering angle θ based on the output value of the steering angle sensor 542. h The value of .

[0044] In addition, the control device 100 and the motor 543 are modularized and manufactured and sold as a motor module. The motor module includes the motor 543 and the control device 100, and is suitable for use in the electric power steering device 1000. In addition, the control device 100 can be manufactured and sold independently of the motor 543 as a control device for controlling the electric power steering device 1000.

[0045] Figure 2 A typical example of the structure of the control device 100 in this embodiment is shown. The control device 100 includes, for example, a power supply circuit 111, an angle sensor 112, an input circuit 113, a communication I / F 114, a drive circuit 115, a ROM 116, and a processor 200. The control device 100 can be implemented as a printed wiring board (PCB: Printed Circuit Board) on which these electronic components are mounted.

[0046] The vehicle speed sensor 300, the steering torque sensor 541, and the steering angle sensor 542 mounted on the vehicle V are connected to the processor 200 in a communicable manner. The vehicle speed is sent from the vehicle speed sensor 300 to the processor 200. The steering torque T is sent from the steering torque sensor 541 to the processor 200. h The steering angle θ is sent from the steering angle sensor 542 to the processor 200. h .

[0047] The processor 200 is a semiconductor integrated circuit, also called a central processing unit (CPU) or a microprocessor. The processor 200 sequentially executes a computer program stored in the ROM 116 and recording a command group for controlling the motor drive, thereby realizing the desired processing. In addition to the processor 200, or in place of the processor 200, the control device 100 may include an FPGA (Field Programmable Gate Array) equipped with a CPU, a GPU (Graphics Processing Unit), an ASIC (Application Specific Integrated Circuit), an ASSP (Application Specific Standard Product), or a combination of two or more circuits selected from these circuits. The processor 200 sets the current command value according to the actual current value and the rotation angle of the rotor of the motor 543, generates a PWM (Pulse Width Modulation) signal, and outputs the PWM signal to the drive circuit 115.

[0048] The power supply circuit 111 is connected to an external power supply (not shown). The power supply circuit 111 generates a DC voltage required by each part of the control device 100. The DC voltage generated in the power supply circuit 111 is, for example, 3V or 5V.

[0049] The angle sensor 112 detects the rotation angle of the rotor of the motor 543 and outputs it to the processor 200. The angle sensor 112 may be a rotary transformer, a Hall element such as a Hall IC, or an MR sensor having a magnetoresistive element. The processor 200 can detect the electrical angle θ of the motor 543 obtained based on the angle sensor 112. m The angular velocity ω [rad / s] of the motor 543 is calculated. In addition, the control device 100 may include a velocity sensor capable of detecting the rotational angular velocity of the motor 543 and an acceleration sensor capable of detecting the rotational angular acceleration of the motor 543 instead of the angle sensor 112 .

[0050] The motor current value detected by the current sensor (not shown) is input to the input circuit 113. In the following description, the motor current value detected by the current sensor (not shown) is referred to as the "actual current value". The input circuit 113 converts the level of the input actual current value to the input level of the processor 200 as needed, and outputs the actual current value to the processor 200. A typical example of the input circuit 113 is an analog / digital conversion circuit.

[0051] The communication I / F 114 is, for example, an input / output interface for transmitting and receiving data in accordance with a vehicle-mounted CAN (Controller Area Network).

[0052] The drive circuit 115 is typically a gate driver or a pre-driver. The drive circuit 115 generates a gate control signal according to the PWM signal, and provides the gate control signal to the gates of the plurality of switching elements of the inverter 545. For example, when the motor 543 as the drive object is a motor that can be driven at a low voltage, the drive circuit 115 as a gate driver may not be necessary. In this case, the function of the gate driver in the drive circuit 115 can be installed in the processor 200.

[0053] The ROM 116 is electrically connected to the processor 200. The ROM 116 is, for example, a writable memory, a rewritable memory, or a read-only memory. As a writable memory, for example, a PROM (Programmable Read Only Memory) is cited. As a rewritable memory, for example, a flash memory and an EEPROM (Electrically Erasable Programmable Read Only Memory) are cited. The ROM 116 stores a control program including a command group for causing the processor 200 to control the motor drive. For example, the control program stored in the ROM 116 is temporarily expanded to a RAM (not shown) during booting.

[0054] like Figure 3 As shown, the control device 100 and the camera device 400 constitute a lane keeping system 1100. The lane keeping system 1100 is a system for keeping a vehicle V driven by a person in the center of a lane L. When the vehicle V is about to leave the center of the lane L, the lane keeping system 1100 controls the steering mechanism 530 through the control device 100 based on the image of the lane L captured by the camera device 400, so as to return the vehicle V to the center of the lane L. The camera device 400 is installed on the windshield FG of the vehicle V, for example.

[0055] like Figure 4As shown, the camera 400 includes a camera body 410 and a camera control unit 420. The camera body 410 captures a portion of the lane L that is located in front of the vehicle V. The camera body 410 is, for example, a camera having a CCD (Charge Coupled Device) image sensor. The camera control unit 420 controls the camera body 410. The camera control unit 420 is a semiconductor integrated circuit similar to the processor 200. The camera control unit 420 outputs the target coordinates x, y based on the image captured by the camera body 410.

[0056] Figure 4 An example of the functional blocks of the processor 200 of the present embodiment is shown. The processor 200 as a computer sequentially executes processing or tasks required for controlling the steering mechanism 530 using each functional block. Figure 4 Each functional block of the processor 200 shown can be installed in the processor 200 as software such as firmware, can be installed in the processor 200 as hardware, or can be installed in the processor 200 as software and hardware. Typically, the processing of each functional block in the processor 200 is described in a computer program in units of software modules and stored in the ROM 116. However, when using an FPGA or the like, all or part of these functional blocks can be installed as a hardware accelerator. In addition, the control method of the control device 100 in this embodiment can be implemented by causing a computer to perform a desired action through a program.

[0057] The processor 200 includes a controller 201, a subtractor SU1, and a torque converter 223. The controller 201 includes a first auxiliary control unit 210, a second auxiliary control unit 220, a vehicle stabilization control unit 240, a disturbance sensitivity control unit 290, a first gain adjustment unit 610, a second gain adjustment unit 620, and an adder AD5. That is, the control device 100 includes a first auxiliary control unit 210, a second auxiliary control unit 220, a vehicle stabilization control unit 240, a disturbance sensitivity control unit 290, a first gain adjustment unit 610, a second gain adjustment unit 620, and an adder AD5. In other words, the functions corresponding to the first auxiliary control unit 210, the second auxiliary control unit 220, the vehicle stabilization control unit 240, the disturbance sensitivity control unit 290, the first gain adjustment unit 610, the second gain adjustment unit 620, and the adder AD1 are installed in the processor 200 of the control device 100.

[0058] The first assist control unit 210 can execute lane keeping control to keep the vehicle V in the lane L. Figure 5As shown, the first assist control unit 210 includes a vehicle state calculation unit 211 and a lane keeping control unit 212. The vehicle state calculation unit 211 calculates a target value of the yaw rate γ of the vehicle V, that is, a yaw rate target value γ, based on input from the imaging device 400. r and the lateral offset y of the vehicle V of Yaw rate target value γ r is the yaw rate γ required for the vehicle V not to deviate from the lane L.

[0059] The yaw rate γ of the vehicle V is a yaw angle indicating the left-right deflection angle of the vehicle V. In other words, the yaw rate γ refers to the angular velocity of the vehicle V when it vibrates in the left-right direction. Figure 3 In the example shown, in a lane L with a curve that turns to the left, the vehicle V before turning the curve is indicated by a solid line, and the vehicle V after turning the curve is indicated by a two-dot chain line. The angle formed by the imaginary line CL1 extending in the direction of travel of the vehicle V indicated by the solid line and the imaginary line CL2 extending in the direction of travel of the vehicle V indicated by the two-dot chain line is the yaw angle that changes when the vehicle V turns the curve. When viewed from above in the vertical direction, for example, imaginary lines CL1 and CL2 coincide with the optical axis of the imaging device body 410. The optical axis of the imaging device body 410 passes through the left-right center of the region IR captured by the imaging device body 410.

[0060] Figure 6 : shows an xy coordinate system. The x-axis is an axis extending in one direction in the horizontal direction. The y-axis is an axis extending in one direction in the horizontal direction and extending in a direction perpendicular to the x-axis. Figure 6 , an example is shown in which a vehicle V moving in the x-axis direction turns in the y-axis direction. of is the y-axis position of the vehicle V relative to the target path R t (x) offset. Target path R t (x) is the center of gravity V of the vehicle V g The path of the target passed is located on the center line LCL of lane L. Figure 6 The xy coordinate position of the vehicle V shown is taken as the center of gravity V of the vehicle V g The xy coordinate position. That is, the lateral offset y of is the target path R t (x) and the center of gravity V g The distance between Figure 6 At the position of the vehicle V shown, the center of gravity V g The xy coordinates of are (0, 0).

[0061] The vehicle state calculation unit 211 calculates the yaw rate target value γ based on the target coordinates x, y input from the camera 400. r and the lateral offset y of In this embodiment, the coordinates (x k-1 ,y k-1 ), coordinates(x k ,y k ) and coordinates (x k+1 ,y k+1 ) are the values ​​of the three target coordinates (x, y). The three target coordinates (x, y) are the target path R on the center line LCL of the target. t (x) contains the coordinates. k-1 ,y k-1 ) is the target path R at the current position of the vehicle V in the x-axis direction t The coordinates on (x). k+1 ,y k+1 ) is the target path R at a position in the x-axis direction ahead of the current position of the vehicle V in the x-axis direction t The coordinates on (x). k ,y k ) is the coordinate (x k-1 ,y k-1 )'s x-axis position and coordinates (x k+1 ,y k+1 ) in the x-axis direction, the target path R at the x-axis direction position of the center t (x) coordinates on the target path R t (x) is the target position in the y-axis direction relative to the position in the x-axis direction. t (x) is represented by, for example, the following formula (1).

[0062]

[0063] Among them, C rp is the coordinate (x k+1 ,y k+1 ) at the target path R t The rate of change of the curvature of (x), C p is the coordinate (x k+1 ,y k+1 ) at the target path R t The curvature of (x), y of is the lateral offset of the vehicle V.

[0064] The vehicle state calculation unit 211 calculates the three coordinates (x k-1 ,y k-1 )、(xk ,y k )、(x k+1 ,y k+1 ) is substituted into the following formula (2) to calculate the values ​​of each term in formula (1). of .

[0065]

[0066] The vehicle state calculation unit 211 calculates the change rate C calculated according to the above formula (2) rp , curvature C p and the coordinate x k-1 , x k+1 Substitute the following formula (3) to calculate the coordinates (x k-1 ,y k-1 ) at the target path R t The radius of curvature R of (x) c (x k-1 ).

[0067]

[0068] The vehicle state calculation unit 211 converts the curvature radius R obtained by the above equation (3) into c (x k-1 ) is substituted into the following formula (4) to calculate the yaw rate target value γ r .

[0069]

[0070] Among them, V v is the driving speed of vehicle V.

[0071] As described above, the vehicle state calculation unit 211 calculates the yaw rate target value γ r and the lateral offset y of .like Figure 5 As shown in FIG. 1 , the yaw rate target value γ calculated in the vehicle state calculation unit 211 is r and the lateral offset y of The information is input to the lane keeping control unit 212 .

[0072] The lane keeping control unit 212 performs lane keeping control. The lane keeping control unit 212 calculates the lane keeping control method so that the vehicle V is on the target path R. t (x) The first command torque T required for driving LKA In this embodiment, the first command torque T LKA is the “first input value” generated by the first assist control unit 210. Figure 7As shown, the lane keeping control unit 212 includes a yaw rate control unit 213, a lateral deviation control unit 214, and an adder AD2. That is, the first assist control unit 210 includes the yaw rate control unit 213, the lateral deviation control unit 214, and an adder AD2.

[0073] The lateral offset control unit 214 is based on the lateral offset y of The lateral offset command torque T is generated y In this embodiment, the lateral offset command torque T y is the "lateral offset command value" generated in the lateral offset control unit 214. Figure 8 As shown, the lateral offset control unit 214 includes a command torque generation unit 214a and a lateral offset adjustment unit 214b. The command torque generation unit 214a generates a torque according to the lateral offset y. of The lateral offset command torque T is generated ya In this embodiment, the command torque generating unit 214a feeds back the lateral displacement y of The output value of the feedback control makes the lateral displacement y of The lateral offset command torque T that converges to zero ya The command torque generation unit 214a performs PI control. The command torque generation unit 214a includes a P gain unit 214c, an I gain unit 214d, an anti-windup control unit 214e, an integral value reset unit 214f, and an adder AD7.

[0074] The lateral offset y is input to the P gain section 214c and the I gain section 214d. of . Lateral offset y of Multiply by the gain K of the P gain unit 214c p The obtained value is input to adder AD7. of Multiply by the gain K of the I gain unit 214d I The obtained value is input to the anti-saturation control unit 214e. The anti-saturation control unit 214e performs anti-saturation control. In I control, if the integral value continues to remain at the set upper and lower limits, it exceeds the target value and overshoots occur. In order to suppress this overshoot, anti-saturation control is performed in the anti-saturation control unit 214e. The output from the anti-saturation control unit 214e is input to the integral value reset unit 214f.

[0075] The integrated value reset unit 214f ​​receives as input the output from the anti-saturation control unit 214e and a signal S indicating whether the lane keeping control is executed. LKA In the signal S LKA When the signal S is a signal indicating that the lane keeping control is being executed, the integrated value reset unit 214f ​​functions as an integrator having a transfer function of 1 / s. s is a Laplace transform. LKAIf the signal indicates that the lane keeping control is not executed, the integral value reset unit 214f ​​sets the output to zero. The output from the integral value reset unit 214f ​​is input to the adder AD7. The adder AD7 adds the output from the P gain unit 214c and the output from the integral value reset unit 214f ​​to generate the lateral deviation instruction torque T ya , and the lateral offset command torque T ya The signal is output to the lateral offset adjustment unit 214b.

[0076] The lateral offset adjustment unit 214b adjusts the lateral offset command torque T t input from the command torque generation unit 214a according to the frequency. ya , and as the lateral offset command torque T y The lateral offset adjustment unit 214b changes the lateral offset command torque T ya Extract the low frequency band and use it as the lateral offset command torque T y And output. Fig. 9 As shown, the transfer function C of the lateral offset adjustment portion 214b is y The gain of (s) is high in a frequency band with a low frequency f, and is low in a frequency band with a high frequency f. More specifically, the transfer function C of the lateral offset adjustment unit 214b in the second frequency band fb2 is y The gain ratio of (s) is the transfer function C of the lateral offset adjustment unit 214b in the first frequency band fb1. y The gain of (s) is low. The second frequency band fb2 is a frequency band higher than the first frequency band fb1. The first frequency band fb1 is a frequency band below the frequency fc. The second frequency band fb2 is a frequency band higher than the frequency fc. The frequency fc is, for example, about 0.1 Hz or more and 0.2 Hz or less. In addition, the first frequency band fb1 and the second frequency band fb2 may also be frequency bands set separately.

[0077] The lateral offset adjustment unit 214b is, for example, a low-pass filter whose cutoff frequency is set to the frequency fc. The lateral offset adjustment unit 214b may also be a phase lag compensation unit that performs phase lag compensation at the frequency fc. The lateral offset adjustment unit 214b adjusts the lateral offset command torque T input from the command torque generation unit 214a to ya The torque in the frequency band below the frequency fc is used as the lateral offset command torque T y Thus, the lateral offset adjustment unit 214b adjusts the lateral offset command torque T according to the frequency f. ya In addition, the lateral offset adjustment unit 214b may also adjust the yaw rate target value γ before conversion into torque according to the frequency f. r , indirectly adjust the lateral offset command torque T according to the frequency f y .

[0078] like Figure 7 As shown, the yaw rate control unit 213 adjusts the yaw rate target value γ according to the yaw rate target value γ. r The yaw rate command torque T is generated γ In this embodiment, the yaw rate command torque T γ is the “yaw rate command value” generated by the yaw rate control unit 213. The yaw rate control unit 213 receives as input the yaw rate target value γ r , the speed of vehicle V v And the coordinates (x k+1 ,y k+1 ) at the target path R t The curvature C of (x) p .like Fig.10 As shown, the yaw rate control unit 213 includes a yaw rate linearization phase compensating unit 213 a , a yaw rate adjusting unit 213 b , a yaw rate phase adjusting unit 213 c , and a torque converting unit 213 d .

[0079] The yaw rate linearization phase compensation unit 213a performs phase compensation so as to linearly approximate the steering torque T without exciting the natural vibration of the yaw rate γ. h In this embodiment, the yaw rate linearization phase compensation unit 213a calculates the input yaw rate target value γ. r Perform phase lag compensation and reduce the specified frequency f d The gain of the frequency band above d is a parameter f set by the model following control in the vehicle stabilization control unit 240. n Low frequency. Parameter f n is the natural frequency f corresponding to the yaw rate γ γ The specified frequency f d For example, it is 0.5 Hz. The natural vibration frequency f corresponding to the yaw rate γ γ The parameter f n For example, it is 2 Hz or more and 4 Hz or less. The yaw rate linearization phase compensation unit 213a adjusts the yaw rate target value γ r Implement phase compensation as the yaw rate target value γ r1 The yaw rate adjustment unit 213 b outputs the yaw rate adjustment unit 213 b .

[0080] In the present embodiment, the disturbance sensitivity control unit 290 can compensate for the disturbance, and the characteristic of the vehicle V can be constrained to the steering torque T by the model following control in the vehicle stabilization control unit 240. h The relationship between the yaw rate γ satisfies T h=Gγ is a linear relationship characteristic. G is a proportionality constant determined by tuning. In the vehicle stabilization control unit 240, the characteristic of the vehicle V can be constrained to a range of the input steering torque T h The frequency f is lower than the natural vibration frequency f of the yaw rate γ γ Therefore, the yaw rate linearization phase compensation unit 213a reduces the relative natural vibration frequency f γ The yaw rate target value γ in the frequency band above the low predetermined frequency f r The gain can satisfy T h = Gγ, use the yaw rate target value γ r Thus, the steering torque T can be linearly approximated without exciting the natural vibration of the yaw rate γ. h In addition, in the present embodiment, by performing phase lag compensation in the yaw rate linearization phase compensator 213a, it is possible to reduce the delay time from when the helmsman recognizes the predicted arrival point to when he actually steers the steering wheel 521 when the first auxiliary control unit 210 is not performing control. Thus, even when the first auxiliary control unit 210 performs auxiliary control, the discomfort felt by the helmsman when steering the steering wheel 521 can be reduced.

[0081] The yaw rate adjustment unit 213b adjusts the yaw rate target value γ according to the frequency. r1 .like Fig. 9 As shown, the transfer function C of the yaw rate adjustment unit 213b is γ The gain of (s) is low in a frequency band with a low frequency f, and is high in a frequency band with a high frequency f. More specifically, the transfer function C of the yaw rate adjustment unit 213b in the first frequency band fb1 is γ The gain of (s) is lower than the transfer function C of the yaw rate adjustment unit 213b in the second frequency band fb2 higher than the first frequency band fb1. γ The yaw rate adjustment unit 213b is, for example, a high-pass filter whose cutoff frequency is set to the frequency fc. The yaw rate adjustment unit 213b may also be a phase lead compensation unit that performs phase lead compensation with a zero point at the frequency fc. The yaw rate adjustment unit 213b adjusts the yaw rate target value γ input from the yaw rate linearization phase compensation unit 213a to r1 The value of the frequency band above the frequency fc in is taken as the yaw rate target value γ r2 In this embodiment, the yaw rate adjustment unit 213b adjusts the yaw rate target value γ according to the frequency f. r1 , thereby adjusting the yaw rate command torque T according to the frequency f γ .

[0082] In this embodiment, the transfer function of the yaw rate adjustment unit 213b is set to C γ (s) Let the transfer function of the lateral offset adjustment unit 214b be C y (s), let K be a constant that is approximately 1 γy When C γ (s) = K γy -C y (s) holds. In this specification, “constant K γy Roughly 1” except for the constant K γy In addition to the case where it is strictly 1, it also includes the constant K γy When the transfer function C of the yaw rate adjustment unit 213b is 0.8 or more and 1.2 or less. γ (s) and the transfer function C of the lateral offset adjustment unit 214b y (s) become mutually complementary.

[0083] For example, when the lateral offset adjustment unit 214b is a phase lag compensation unit, the transfer function C of the lateral offset adjustment unit 214b is y (s) is represented by, for example, the following formula (5).

[0084]

[0085] Where s is the Laplace transform and f1 is the transfer function C y (s) is the frequency of the zero point [Hz], f2 is the transfer function C y (s) frequency of the pole [Hz], K r It is a parameter used to adjust the weighting of lateral offset control and yaw rate control. A graph with the vertical axis representing gain or loop gain and the horizontal axis representing the logarithm of frequency is called a gain graph. In the gain graph, the zero point refers to the intersection of the gain curve and the horizontal axis representing 0dB, and the pole refers to the maximum point of the gain curve. For example, by making the frequency of the pole higher than the frequency of the zero point, phase lead compensation can be applied. The larger the interval between the frequency of the pole and the frequency of the zero point, the greater the phase lead amount.

[0086] By 0≤K r Adjust parameter K within the range of ≤(f1+f2) / f2 r , which can adjust the weighting of the lateral offset control and the yaw rate control. The transfer function C of the lateral offset adjustment unit 214b is y (s) is expressed by the above formula (5), in K r When the yaw rate adjustment unit 213b has a transfer function C γ (s) is represented by the following formula (6).

[0087]

[0088] like Fig.10 As shown in FIG. 1 , the yaw rate phase adjustment unit 213 c receives the yaw rate target value γ output from the yaw rate adjustment unit 213 b. r2 , the speed of vehicle V v , coordinates(x k+1 ,y k+1 ) at the target path R t The curvature C of (x) p The yaw rate phase adjustment unit 213c adjusts the yaw rate target value γ output from the yaw rate adjustment unit 213b. r2 The transfer function C of the yaw rate phase adjustment unit 213c is γp (s) includes a transfer function P of the second nominal model NM2 described later. nv The natural vibration frequency f in (s) and the yaw rate γ γ The equivalent parameter f n In this embodiment, the transfer function C of the yaw rate phase adjustment unit 213c is converted into a transfer function of different parameters. γp (s) can be obtained by converting the transfer function P of the second nominal model NM2 nv The natural vibration frequency f in (s) and the yaw rate γ γ The equivalent parameter f n The transfer function C of the yaw rate phase adjustment unit 213c is converted into a transfer function of different parameters. γp (s) is represented by, for example, the following formula (7).

[0089]

[0090] Where s is the Laplace transform, f n is the natural vibration frequency f related to the yaw rate γ γ The equivalent parameter, f r is the natural vibration frequency f that is related to the yaw rate γ γ The expected value for the corresponding parameter.

[0091] like Fig.10 As shown, the yaw rate phase adjustment unit 213c is based on the above transfer function C γp (s) to adjust the yaw rate target value γ r2 , and used as the yaw rate target value γ r3 The torque conversion unit 213d converts the yaw rate target value γ into r3 Converted into yaw rate command torque T γ As described above, in this embodiment, since the steering torque T h The relationship with the yaw rate γ is T h=Gγ, so the gain of the torque conversion unit 213d is the proportional constant G.

[0092] In addition, the yaw rate adjustment unit 213b adjusts the yaw rate target value γ according to the frequency f. r1 , indirectly adjust the yaw rate command torque T according to the frequency f γ The yaw rate adjustment unit 213b may also be provided after the torque conversion unit 213d, and directly adjust the yaw rate command torque T output from the torque conversion unit 213d according to the frequency f. γ .

[0093] like Figure 7 As shown in FIG. 1 , the yaw rate command torque T outputted from the yaw rate control unit 213 is γ and the lateral deviation command torque T outputted from the lateral deviation control unit 214 y The two torques are added together in the adder AD2 to obtain the first command torque T LKA And output. Figure 4 As shown, the first command torque T outputted from the first assist control unit 210 LKA The signal is input to the first gain adjustment unit 610 .

[0094] The first gain adjustment unit 610 adjusts the first command torque T LKA The first gain adjustment unit 610 adjusts the first command torque T LKA Multiply by the first gain K1 to obtain the first command torque T LKA1 The first gain K1 is a variable value. The first gain K1 is expressed by K1=1-K2 using the second gain K2 of the second gain adjustment unit 620. The first command torque T LKA1 The signal is input to the adder AD5 and the vehicle stabilization control unit 240 .

[0095] The subtractor SU1 receives the steering angle θ detected by the steering angle sensor 542. h Subtractor SU1 is used to calculate the steering angle θ h Subtract the steering angle θ detected by the steering torque sensor 541 and the steering angle sensor 542 s , and output to the torque conversion unit 223.

[0096] The torque conversion unit 223 receives the value output from the subtractor SU1. The torque conversion unit 223 multiplies the value output from the subtractor SU1 by a gain and outputs a steering torque T h The gain in the torque converter 223 is equal to the spring constant K of the torsion bar 546 tor . Steering angle θ h With steering angle θ s The difference is multiplied by the spring constant K of the torsion bar 546 torThe value obtained is the torsion bar torque, that is, the steering torque T h . Steering torque T h The signal is input to the second gain adjustment unit 620 .

[0097] The second gain adjustment unit 620 adjusts the steering torque T h The second gain adjustment unit 620 adjusts the steering torque T h Multiply by the second gain K2 to obtain the steering torque T h1 The second gain K2 is greater than or equal to 0 and less than or equal to 1. The second gain K2 is based on the steering torque T h According to the above relationship K1=1-K2, when the second gain K2 is 1, the first gain K1 is 0, when the second gain K2 is 0.5, the first gain K1 is 0.5, and when the second gain K2 is 0, the first gain K1 is 1. The larger the value of the second gain K2, the greater the steering torque T input by the steersman via the steering wheel 521. h The greater the influence of the first gain K1, the greater the value of the first command torque T outputted from the first assist control unit 210. LKA The first gain K1 when the first auxiliary control unit 210 performs lane keeping control is greater than the first gain K1 when the first auxiliary control unit 210 does not perform lane keeping control. The steering torque T output from the second gain adjustment unit 620 is h1 is input to the adder AD5. The adder AD5 converts the first command torque T LKA1 and steering torque T h1 The values ​​are added and output to the second assist control unit 220 .

[0098] The second assist control unit 220 generates a second command torque T , which is input to the vehicle stabilization control unit 240 , based on the steering input value input from the steering wheel 521 of the vehicle V. r In this embodiment, the steering input value is the steering torque T h In this embodiment, the second command torque T r is a “second input value” generated by the second assist control unit 220. The second assist control unit 220 generates the second command torque T r To control the torque of the motor 543, thereby controlling the reaction force transmitted from the steering wheel 521 to the helmsman. Fig.11 As shown, the second assist control unit 220 includes a basic assist control unit 221 and a phase compensator 222 .

[0099] The basic assist control unit 221 generates a torque bar torque based on the torsion bar 546, that is, the steering torque T h The calculated input torque T ad, generating a self-aligning torque T for the tires 529A and 529B of the vehicle SAT The auxiliary torque T that compensates at least part of ass In this embodiment, the basic assist control unit 221 is based on the steering torque T h The steering torque T obtained by multiplying the second gain K2 h1 With the first command torque T LKA The first command torque T obtained by multiplying the first gain K1 LKA1 The input torque T calculated by adding ad , generating auxiliary torque T ass .

[0100] In this embodiment, the basic assist control unit 221 sets the input torque T ad Multiply by the auxiliary gain K ass The output auxiliary torque T ass . Fig.12 shows the input torque T ad With assist torque T ass An example of a relationship between Fig.12 In the curve diagram, the horizontal axis is the input torque T ad , the vertical axis is the auxiliary torque T ass , assist torque T ass Relative to input torque T ad The slope is the auxiliary gain K ass . Input torque T ad , auxiliary torque T ass and auxiliary gain K ass Meet dT ass / dT ad =K ass Such as Fig.12 As shown, the assist torque T ass For example, with the input torque T ad As it gets bigger, it gets bigger exponentially. Fig.11 As shown, the assist torque T output from the basic assist control unit 221 ass is input to the phase compensator 222.

[0101] In addition, the basic assist control unit 221 may also be configured according to the input torque T ad and the speed V of vehicle V v The auxiliary torque T is generated ass The basic assist control unit 221 may have, for example, a predetermined input torque T ad , driving speed V v and the assist torque T ass The assist torque T is determined by referring to the lookup table (LUT). ass .

[0102] The phase compensator 222 in this embodiment adjusts the gain within the range of the steering frequency that can be taken when the steersman operates the steering wheel 521, and compensates for the rigidity of the torsion bar 546. The range of the steering frequency that can be taken is, for example, 5 Hz or less. The phase compensator 222 may also adjust the gain of the assist torque T when the steering frequency is 5 Hz or less. ass For example, first-order phase compensation is applied. The first-order phase compensation is represented by the transfer function C(s) of equation (8), for example.

[0103]

[0104] Here, s is the Laplace transform, f3 is the frequency of the zero point of the transfer function C(s) [Hz], and f4 is the frequency of the pole of the transfer function C(s) [Hz].

[0105] The phase compensator 222 is based on the assist torque T output from the basic assist control unit 221. ass and the gain of the phase compensator 222 to generate the second command torque T r That is, according to the assist torque T ass The second command torque T is calculated as the second input value. r For example, the phase compensator 222 is a stabilizing compensator that can adjust the assist torque T ass Stability phase compensation is applied. The phase compensator 222 may have a transfer function of the second order or higher whose frequency characteristics vary according to the gain of the transfer function C(s). The transfer function of the second order or higher is represented by a parameter of responsiveness and a parameter of attenuation ratio (damping). The transfer function C(s) of the second order or higher can be represented by equation (9), for example. By setting the order of the transfer function C(s) to the second order, damping can be given to the characteristics of the transfer function C(s). By changing the damping, the phase characteristics can be adjusted.

[0106]

[0107] In equation (9), s is the Laplace transformer, ω3 is the frequency of the zero point of the transfer function C(s), ω4 is the frequency of the pole of the transfer function C(s), ζ3 is the attenuation ratio of the zero point, and ζ4 is the attenuation ratio of the pole. The frequency ω4 of the pole is lower than the frequency ω3 of the zero point.

[0108] like Figure 4 As shown, the vehicle stabilization control unit 240 receives the first command torque T outputted from the first gain adjustment unit 610. LKA1 and the second command torque T outputted from the second assist control unit 220 r .like Fig.13As shown, the vehicle stabilization control unit 240 includes a second model following control unit 241 , a second state feedback unit 242 , a subtractor SU5 , and an adder AD6 .

[0109] The subtractor SU5 receives the first command torque T LKA1 and the second command torque T r The command torque T obtained by adding rL The subtractor SU5 subtracts the input command torque T rL The second correction torque T outputted from the second model following control unit 241 is subtracted. f2 The output from the subtractor SU5 is input to the adder AD6 and the second model following control unit 241. The adder AD6 adds the output from the second state feedback unit 242 to the output from the subtractor SU5 to obtain the command torque T . rL1 Output to the disturbance sensitivity control unit 290. In this embodiment, the command torque T rL1 The first command torque T is multiplied by the first gain K1. LKA1 The second command torque T multiplied by the second gain K2 r And the calculated "instruction value".

[0110] In the present embodiment, the second model following control unit 241 is a model following controller configured to perform model following control. The second model following control unit 241 generates a control signal for the command torque T according to the yaw rate γ and the second nominal model NM2. rL The second correction torque T for correction f2 In this embodiment, the second correction torque T f2 is fed back to the command torque T rL The second nominal model NM2 is an internal model used as a model for constraining the second controlled object 580 when controlling the second controlled object 580. In the present embodiment, the second controlled object 580 is the actual steering angle θ of the tires 529A and 529B. t The device model with yaw rate γ as input and output. Figure 6 As shown, when viewed along the vertical direction, the actual rudder angle θ t It is the angle at which the tires 529A and 529B are inclined in the left-right direction of the vehicle body relative to the front-rear direction of the vehicle body of the vehicle V. Fig.13 The second controlled object 580 shown is the vehicle V. The transfer function G of the second controlled object 580 is θ γ (s) is determined by the characteristics of vehicle V.

[0111] In the present embodiment, the second model following control unit 241 generates the second correction torque T according to the yaw rate γ. f2 , and fed back to the command torque TrL The second model following control unit 241 includes a second inverse nominal model 243 , a filter 244 , a torque conversion unit 245 , and a subtractor SU6 .

[0112] The second model tracking control unit 241 is configured to constrain the transfer function of the second controlled object 580 to be the transfer function P of the second nominal model NM2 in a frequency band where the gain is approximately 1 in the gain characteristic of the complementary sensitivity function of the modeling error between the second controlled object 580 as the plant model and the second nominal model NM2. nv (s).

[0113] In this specification, regarding "the transfer function of a certain controlled object is constrained to be the transfer function of a certain nominal model", for example, when observing the input-output relationship, the control object is controlled so that the transfer function of the certain controlled object appears to be the transfer function of a certain nominal model. In addition, in this specification, regarding "a certain gain is approximately 1", in addition to the case where a certain gain is 1, for example, it also includes the case where a certain gain is greater than 0.8 and less than 1.2. This numerical range is, for example, a range in which the gain of the actual interference suppression characteristic can be adjusted to 1 based on the positive efficiency and reverse efficiency of the worm gear when the reduction mechanism 544 connected to the motor 543 has a worm gear. Since the efficiency of the worm gear is about 0.8, the gain needs to be adjusted by ±0.2 relative to the target value 1.

[0114] The complementary sensitivity function with respect to the modeled error between the second controlled object 580 and the second nominal model NM2 is a complementary sensitivity function of the inner loop formed by the second model tracking control unit 241. In the present embodiment, the complementary sensitivity function in the second model tracking control unit 241 is equal to the transfer function Q3(s) of the filter 244. The transfer function Q3(s) as the complementary sensitivity function has a gain of approximately 0 dB in the frequency band that the filter 244 passes, that is, the gain in the transfer function is approximately 1. That is, in the present embodiment, the second model tracking control unit 241 is configured to convert the transfer function Q3(s) of the second controlled object 580 into a frequency band in which the gain is approximately 1 in the gain characteristic of the transfer function Q3(s). θ γ (s) is constrained to be the transfer function P of the second nominal model NM2 nv Thus, the vehicle stabilization control unit 240 performs the model following control by the second model following control unit 241, and changes the transfer function G of the second controlled object 580 as the plant model to θ γ (s) The transfer function P of the second nominal model NM2 is constrained to be specified nv (s).

[0115] The second inverse nominal model 243 is an inverse model of the second nominal model NM2 for constraining the second controlled object 580. The transfer function P of the second nominal model NM2 is nv (s) is represented by the following equation (10), for example. The transfer function P of the second inverse nominal model 243 nv -1 (s) is represented by the following formula (11).

[0116]

[0117] Where s is the Laplace transform, f n is the natural frequency f corresponding to the yaw rate γ γ The parameter G θ γ (0) is the actual steering angle θ of the tires 529A and 529B of the vehicle V. t The steady-state gain of the transfer function to the yaw rate γ.

[0118] The transfer function P of the second nominal model NM2 nv The gain in (s) is, for example, Fig.14 As Fig.14 As shown, the transfer function P of the second nominal model NM2 nv The gain in (s) is equal to the natural vibration frequency f corresponding to the yaw rate γ. γ The parameter f n The steady-state gain G is θ γ (0), in the ratio parameter f n As described above, by reducing the yaw rate target value γ in the yaw rate linearization phase compensation unit 213a, r The specified frequency f d The gain of the above frequency band can be obtained in the transfer function P of the second nominal model NM2. nv The gain in (s) becomes the steady-state gain G θ γ The second control object 580 is controlled in the region of (0).

[0119] The second inverse nominal model 243 receives as input the output of the second controlled object 580, that is, the yaw rate γ. The second inverse nominal model 243 outputs the steering angle θ based on the above equation (11) and the input yaw rate γ. tp . Rudder angle θ tp When the output value of the second nominal model NM2 becomes the same as the output value of the second controlled object 580, the actual steering angle θ input to the second nominal model NM2 is t The value of is equal. tpis input to the torque conversion unit 245. The torque conversion unit 245 converts the steering angle θ tp Convert to torque T p2 And output.

[0120] The subtractor SU6 subtracts the output of the subtractor SU5 from the output of the torque converter 245 to generate a differential torque T a2 The differential torque T output from the subtractor SU6 a2 is input to the filter 244. The filter 244 processes the differential torque T a2 Filtering is performed to obtain the second correction torque T f2 And the output is given to the subtractor SU5.

[0121] By constraining the second controlled object 580 to the second nominal model NM2 by the second model following control unit 241, the natural frequency f of the yaw rate γ can be set to γ The transfer function P of the second nominal model NM2 is constrained to nv The parameter f in (s) n In this embodiment, the transfer function C of the yaw rate phase adjustment unit 213c is expressed by the above-mentioned equation (7): γp (s), the transfer function P of the second nominal model NM2 can be nv The denominator in (s) is the transfer function C γp The numerator of (s) cancels out and is replaced by the transfer function C γp Thus, the parameter f n The value of is converted into the parameter f in formula (7) r Therefore, the transfer function C of the yaw rate phase adjustment unit 213c is γp (s), the transfer function P of the second nominal model NM2 can be nv The natural vibration frequency f in (s) and the yaw rate γ γ The equivalent parameter f n Converted to the desired different value. The natural vibration frequency f of the desired yaw rate γ γ The equivalent parameter f r For example, according to the curvature C p For example, in the case of curvature C p When it is smaller, increase the parameter f r , at curvature C p When it is larger, reduce the parameter f r Parameter f r Preferably, it is about 2 Hz or more and 4 Hz or less.

[0122] In addition, when the second model tracking control unit 241 is not constrained to the parameter f n In the case of yaw rate γ, the natural vibration frequency f γFor example, it is about 1 Hz or more and 1.5 Hz or less. By using the second model tracking control unit 241 to adjust the natural frequency f of the yaw rate γ to γ Constraints for parameters f r , which can increase the natural vibration frequency f of the yaw rate γ γ , the resonance of the yaw rate γ can be less likely to occur. As a result, the running of the vehicle V can be further stabilized.

[0123] The second state feedback unit 242 generates a state feedback signal based on the yaw rate γ or the steering angle θ of the vehicle V. s , outputs the state feedback torque T used to make the characteristics of the vehicle V approximate to the transfer function of the first-order lag fb .like Fig.15 As shown in FIG. 1 , the second state feedback unit 242 includes a yaw rate converter 242a, a switch unit 242b, and a torque converter 242c. The switch unit 242b switches the yaw rate γ of the vehicle V and the steering angle θ. s Which one is used to calculate the state feedback torque T fb When there is a signal from the camera 400, the switch unit 242b outputs the yaw rate γ calculated based on the camera 400 to the torque converter 242c. When there is no signal from the camera 400, the switch unit 242b outputs the yaw rate γ calculated based on the steering angle θ. s The calculated yaw rate γ is output to the torque conversion unit 242c. The yaw rate conversion unit 242a converts the input steering angle θ into s The yaw rate is converted to yaw rate γ and output to the switch unit 242b. The transfer function of the yaw rate converter 242a is G θ γ (s) / g tot To indicate. θ γ (s) is the actual rudder angle θ t The transfer characteristic to the yaw rate γ is the transfer function of the second controlled object 580. 1 / g tot is the steering angle θ s To the actual rudder angle θ t Conversion gain. g tot is related to the steering angle θ s To the actual rudder angle θ t Parameters equivalent to the gear ratio.

[0124] The torque conversion unit 242c converts the yaw rate γ input from the switch unit 242b into the state feedback torque T fb The transfer function C1(s) of the torque conversion unit 242c is expressed by the following equation (12).

[0125]

[0126] Among them, s is the Laplace transform, G θ γ (0), C r and τ n is a constant value determined by the specifications of the vehicle V. G θ γ (0), C r and τ n For example, according to the driving speed V v , wheelbase, the turning force of tires 529A and 529B, and the yaw moment of vehicle V. θ γ (0) is the actual steering angle θ of the tires 529A and 529B of the vehicle V. t The steady-state gain of the transfer function to the yaw rate γ.

[0127] like Fig.13 As shown, the state feedback torque T output from the second state feedback unit 242 is fb The output from the subtractor SU5 is added to the adder AD6. The adder AD6 adds the state feedback torque T to the output from the subtractor SU5. fb As the command torque T rL1 , and output to the interference sensitivity control unit 290.

[0128] The transfer function of the second controlled object 580, that is, the transfer function G of the characteristic of the vehicle V θ γ (s) is represented by the following formula (13).

[0129]

[0130] Where s is the Laplace transform, ω n is the parameter of responsiveness, ξ is the parameter of attenuation ratio (damping), G θ γ (0) is a constant determined by the specifications of the vehicle V, T g is determined by the specifications of the vehicle V and the driving speed V of the vehicle V v Determined constant.

[0131] The second state feedback unit 242 multiplies the state feedback gain K by feedback. d The calculated state feedback torque T fb , the parameter ξ of the attenuation ratio of the above equation (13) can be controlled. If the parameter ξ of the attenuation ratio is set to 1 by the second state feedback unit 242, the right term of the above equation (13) can be approximated by a first-order lag transfer function as shown in the following equation (14).

[0132]

[0133] Among them, f γ is the natural vibration frequency of the yaw rate γ.

[0134] By being able to approximate the transfer function of the second controlled object 580 as in the above-mentioned equation (14), it is possible to easily constrain the second controlled object 580 to have the transfer function P shown in the above-mentioned equation (10): nv In addition, by expressing the second nominal model NM2 with a first-order lag transfer function such as equation (10), even if the device characteristics of the second controlled object 580 change due to a change in the number of passengers in the vehicle V, the natural vibration frequency f of the yaw rate γ can be adjusted by the second nominal model NM2. γ Constrained to be the desired parameter f r As described above, in the present embodiment, by combining the state feedback by the second state feedback unit 242 and the model following control by the second model following control unit 241 , it is possible to realize the characteristics of the vehicle V that is stable and easy to steer.

[0135] For example, if the second controlled object 580 is constrained to the second nominal model NM2 by the model following control to change the natural frequency f of the yaw rate γ, γ , when the modeling error between the second controlled object 580 and the second nominal model NM2 is large, the robustness stability is reduced and the natural vibration frequency f of the yaw rate γ cannot be adjusted. γ In contrast, in the present embodiment, the state feedback gain K of the second state feedback unit 242 is adjusted in the vehicle stabilization control unit 240. d As described above, the transfer function G of the second controlled object 580 is θ γ (s) By performing a first-order approximation, the transfer function G of the second controlled object 580 can be θ γ (s) is close to the transfer function P of the second nominal model NM2 nv (s), the modeling error can be reduced. Thus, by performing the model following control in the second model following control unit 241, a stable and desired natural vibration frequency f of the yaw rate γ can be achieved. γ The relationship between the modeling error and the robust stability in the model following control will be described in detail in the model following control of the first model following control unit 230 described later.

[0136] like Fig.16 As shown, the command torque T outputted from the vehicle stabilization control unit 240 is rL1The disturbance sensitivity control unit 290 is inputted. The disturbance sensitivity control unit 290 includes a first model tracking control unit 230, a first state feedback unit 280, an adder AD3, and a subtractor SU2.

[0137] The first model following control unit 230 generates a response to the command torque T based on the output of the first controlled object 560 including the motor 543 provided in the steering mechanism 530 and the first nominal model NM1 based on the structure of the first controlled object 560. rL1 The first correction torque T for correction f1 In this embodiment, the first correction torque T f1 is the command torque T which is the correction value. rL1 The first correction torque T is the "correction value". If the command value is an angle, the correction value is an angle. f1 is fed back to the command torque T rL1 The first nominal model NM1 is an internal model of the model used to constrain the first controlled object 560 when controlling the first controlled object 560. The first nominal model NM1 will be described in detail in the following section. The first model tracking control unit 230 is a model tracking controller configured to perform model tracking control. The specific structure of the first model tracking control unit 230 will be described in detail in the following section.

[0138] Subtractor SU2 subtracts the command torque T rL1 The first correction torque T outputted from the first model following control unit 230 is subtracted. f1 The output from the subtractor SU2 is input to the adder AD3 and the first model following control unit 230. The adder AD3 adds the command torque T rL2 Output to adder AD1, the command torque T rL2 The adder AD1 adds the output from the adder AD3 to the output from the first state feedback unit 280. h and disturbance torque T d The obtained value of the command torque T rL3 The first controlled object 560 is outputted to the first controlled object 560. The first controlled object 560 is inputted as the command torque T rL3 , set the output to the steering angle θ s The control object. Fig.13 As shown, the steering angle θ output from the first control object 560 is s is input to the conversion unit 570. The conversion unit 570 converts the steering angle θ s Multiply by the conversion gain 1 / g tot The actual steering angle θ is output t The actual steering angle θ output from the conversion unit 570 tis input to the second control object 580. Figure 4 , the first controlled object 560 , the conversion unit 570 , and the second controlled object 580 are collectively represented as a controlled object block 590 .

[0139] Disturbance torque T d It is the difference between the actual output torque of the motor 543 and the ideal output torque of the motor 543. d The disturbance torque T includes the disturbance torque applied from the outside to the first controlled object 560. d For example, it includes the excess torque caused by friction and vibration caused by mechanical elements such as the motor 543 and the speed reduction mechanism 544, the torque fluctuation caused by the motor 543, the self-aligning torque T SAT And the interference torque that may be generated when driving on unpaved sloped roads or gravel roads.

[0140] like Fig.16 As shown, in this embodiment, the first model tracking control unit 230 is based on the steering angle θ s The first correction torque T is generated. f1 , and fed back to the command torque T rL1 The first model tracking control unit 230 includes a first inverse nominal model 231, a first filter 232a, a second filter 232b, an auxiliary adjustment unit 270, a subtractor SU3, and an adder AD4. In the present embodiment, the first filter 232a is a high-pass filter. The first filter 232a has a first cutoff frequency Cf1. The first cutoff frequency Cf1 is, for example, greater than 2 Hz and less than 10 Hz. In the present embodiment, the first cutoff frequency Cf1 is greater than 5 Hz and less than 10 Hz.

[0141] In the present embodiment, the second filter 232b is a low-pass filter. The second filter 232b has a second cut-off frequency Cf2 higher than the first cut-off frequency Cf1. The second cut-off frequency Cf2 is, for example, above 3 Hz and below 50 Hz. However, the upper limit of the second cut-off frequency Cf2 can be set to a range of about 140 Hz and below 200 Hz. The order of the second filter 232b is above three orders. The second filter 232b can also be composed of a plurality of low-pass filters, for example. The first filter 232a and the second filter 232b are coupled in series.

[0142] The first model tracking control unit 230 is configured to adjust the transfer function P of the first controlled object 560 to a value within a frequency band where the gain of the complementary sensitivity function T(s) with respect to the modeling error between the first controlled object 560 and the first nominal model NM1, that is, the complementary sensitivity gain GT, is approximately 1. s (s) is constrained to be the transfer function P of the first nominal model NM1sn (s).

[0143] The complementary sensitivity function T(s) is the complementary sensitivity function of the inner loop formed by the first model tracking control unit 230. Fig.17 , the complementary sensitivity gain GT in the complementary sensitivity function T(s) is shown. The complementary sensitivity gain GT is the gain of the complementary sensitivity function T(s) as a transfer function, and is the absolute value of the complementary sensitivity function T(s). Fig.17 As shown, in the frequency band where the frequency f is above the first cutoff frequency Cf1 and below the second cutoff frequency Cf2, the gain of the complementary sensitivity function T(s) is 0 dB, that is, the complementary sensitivity gain GT in the transfer function is 1. That is, the first cutoff frequency Cf1 is the lower limit value of the frequency band where the complementary sensitivity gain GT becomes 1. The second cutoff frequency Cf2 is the upper limit value of the frequency band where the complementary sensitivity gain GT becomes 1.

[0144] The transfer function P of the first controlled object 560 s (s) is the plant characteristic for model following control. The transfer function P of the first controlled object 560 is s (s) is represented by, for example, the following formula (15).

[0145]

[0146] Here, s is the Laplace transform, J is a parameter representing the inertia moment of the steering mechanism 520, and B is a parameter representing the viscous friction coefficient of the steering mechanism 520. SAT Is the automatic return torque gain. Automatic return torque gain K SAT is the self-aligning torque T generated by the tires 529A and 529B of the vehicle V SAT Relative to the steering angle θ s The slope of . Fig.18 The self-aligning torque T SAT With steering angle θ s An example of a relationship between Fig.18 In the curve diagram, the horizontal axis is the steering angle θ s , the vertical axis is the self-aligning torque T SAT , automatic return torque T SAT Relative to the steering angle θ s The slope is the automatic return torque gain K SAT . Steering angle θ s , Automatic return torque T SAT And the automatic return torque gain K SAT Meet dT SAT / dθ s =K SAT Such as Fig.18 As shown, for example, at a steering angle θs Before the steering angle θ s The larger the self-aligning torque T SAT The larger the steering angle θ is, the s When the steering angle θ is larger than a certain value, s The larger the self-aligning torque T SAT The smaller.

[0147] The first inverse nominal model 231 is an inverse model of the first nominal model NM1 for constraining the first controlled object 560. The transfer function P of the first nominal model NM1 is sn (s) is represented by the following equation (16), for example. The transfer function P of the first inverse nominal model 231 is sn -1 (s) is represented by, for example, the following formula (17).

[0148]

[0149] In equations (16) and (17), s is the Laplace transform, J n is a parameter representing the inertia moment of the first nominal model NM1, B n is a parameter representing the viscous friction coefficient of the first nominal model NM1. sn (s) and the transfer function P of the first inverse nominal model 231 sn -1 (s) is not limited to the examples shown in formula (16) and formula (17), and is not particularly limited.

[0150] like Fig.16 As shown, the first inverse nominal model 231 receives the output of the first controlled object 560. Specifically, the first inverse nominal model 231 receives the steering angle θ s The first inverse nominal model 231 is based on the above equation (17) and the input steering angle θ s The output torque T p That is, the first model following control unit 230 calculates the torque T using the first nominal model NM1 based on the output of the first controlled object 560. p When the output value of the first nominal model NM1 becomes the same as the output value of the first controlled object 560, the torque T p It is equal to the value of the torque input to the first nominal model NM1.

[0151] The subtractor SU3 subtracts the output of the subtractor SU2 from the output of the first inverse nominal model 231 to generate a differential torque T a That is, the subtractor SU3 subtracts the torque T p Subtract the first correction torque T fed backf1 Then the state compensation value V described later is fed back s The previous command torque T rL1 The differential torque T a . Differential torque T a For example, the disturbance torque T d The differential torque T output from the subtractor SU3 is a After being input to the second filter 232b and subjected to low-pass filtering, it is input to the first filter 232a and subjected to high-pass filtering. The differential torque T after being subjected to filtering by the first filter 232a and the second filter 232b is a The differential torque T after filtering by the first filter 232a and the second filter 232b is input to the adder AD4. a The frequency components lower than the first cutoff frequency Cf1 and the frequency components higher than the second cutoff frequency Cf2 are removed. That is, the differential torque T after filtering by the first filter 232a and the second filter 232b is a The frequency component T is above the first cutoff frequency Cf1 and below the second cutoff frequency Cf2. aM .

[0152] The auxiliary adjustment unit 270 generates a compensation value for friction and interference, and adjusts the differential torque T a In this embodiment, the auxiliary adjustment unit 270 adjusts the differential torque T a The frequency component T aM The auxiliary adjustment unit 270 is coupled in parallel to the first filter 232a. The auxiliary adjustment unit 270 includes a friction compensation value calculation unit 250, a disturbance compensation value calculation unit 260, and a subtractor SU4.

[0153] The subtractor SU4 subtracts the output value from the first filter 232a from the output value from the second filter 232b. Here, the output value from the second filter 232b is obtained from the differential torque T a The value of the frequency component higher than the second cutoff frequency Cf2 is removed. The output value from the first filter 232a is obtained from the differential torque T a The value of the frequency component higher than the second cutoff frequency Cf2 and the frequency component lower than the first cutoff frequency Cf1 is removed. Therefore, the value output from the subtractor SU4 becomes the differential torque T a The frequency component T lower than the first cutoff frequency Cf1 in aL The output of the subtractor SU4 is input to the friction compensation value calculation unit 250 and the disturbance compensation value calculation unit 260. The frequency component T aL Including friction, self-aligning torque T SAT, disturbance torque caused by looseness of the first controlled object 560 , and torque fluctuation generated by the first controlled object 560 , etc.

[0154] The friction compensation value calculation unit 250 calculates the friction compensation value according to the differential torque T a The friction compensation value V for compensating at least a part of the friction force generated by the first controlled object 560 is calculated. f As described above, the value input to the friction compensation value calculation unit 250 from the subtractor SU4 becomes the differential torque T a The frequency component T lower than the first cutoff frequency Cf1 in aL Therefore, in the present embodiment, the friction compensation value calculation unit 250 calculates the friction compensation value according to the differential torque T a The friction compensation value V is calculated by using the frequency component lower than the first cut-off frequency Cf1 in f .

[0155] The friction compensation value calculation unit 250 includes a limiter 252 and a gain adjuster 253. The limiter 252 limits the output value from the subtractor SU4. When the input value exceeds the upper or lower threshold, the limiter 252 limits the input value to the upper or lower threshold. The gain adjuster 253 multiplies the output value from the limiter 252 by a gain K3. The friction compensation value calculation unit 250 calculates the differential torque T a The frequency components lower than the first cut-off frequency Cf1 in the friction compensation value V are calculated by applying the limiter 252 and the gain K3. f The threshold value of the limiter 252 and the value of the gain K3 are predetermined to be set, for example, based on the friction force actually generated by the first controlled object 560 .

[0156] The friction compensation value V output from the friction compensation value calculation unit 250 is f is the differential torque T a The frequency component T aL Generally, since the first controlled object 560 requires moderate friction, the friction compensation value calculation unit 250 calculates a value smaller than the friction actually generated by the first controlled object 560 as the friction compensation value V f Thus, it is possible to achieve high-precision friction compensation while maintaining a moderate friction force on the first controlled object 560. Based on the friction compensation value V f The objects of friction compensation are, for example, the friction of the motor 543, the friction of the speed reduction mechanism 544, and the left-right difference in friction of the speed reduction mechanism 544.

[0157] Here, the differential torque T a The frequency component T aLIn addition to the friction component, the self-aligning torque T generated by the first controlled object 560 is also included. SAT , the disturbance torque caused by the looseness of the first controlled object 560, and the torque fluctuation generated by the first controlled object 560. Therefore, after the frequency component T is adjusted by the limiter 252 and the gain adjuster 253, aL The friction compensation value V obtained by processing f The automatic return torque T generated on the first control object 560 is also included. SAT , a compensation value for compensating at least a portion of a disturbance torque caused by looseness generated by the first controlled object 560 and a torque fluctuation generated by the first controlled object 560 .

[0158] The vehicle V equipped with the electric power steering device 1000 can travel in a driving mode having an automatic driving mode and a manual driving mode. In this case, the gain K3 of the gain adjuster 253 can also be switched according to the driving mode. The greater the gain K3 of the gain adjuster 253, the greater the degree of friction reduction.

[0159] The disturbance compensation value calculation unit 260 calculates the self-aligning torque T generated on the first controlled object 560. SAT The interference compensation value V for compensating at least a part of d In this embodiment, the interference compensation value V d The compensation value includes a compensation value for compensating at least a part of the friction force generated by the first controlled object 560, the disturbance torque caused by the looseness generated by the first controlled object 560, and the torque fluctuation generated by the first controlled object 560. The disturbance compensation value calculation unit 260 calculates the torque T output from the first inverse nominal model 231. p With the command torque T rL1 The differential torque T a To calculate the interference compensation value V d That is, the disturbance compensation value calculation unit 260 calculates the torque T based on the output of the first controlled object 560 using the first nominal model NM1. p With the command torque T rL1 The differential torque T a To calculate the interference compensation value V d As described above, the value from the subtractor SU4 input to the disturbance compensation value calculation unit 260 becomes the differential torque T a Therefore, in this embodiment, the disturbance compensation value calculation unit 260 calculates the frequency component lower than the first cut-off frequency Cf1 according to the differential torque T a The interference compensation value V is calculated by using the frequency components lower than the first cutoff frequency Cf1 in d .

[0160] The disturbance compensation value calculation unit 260 includes a limiter 262 and a gain adjuster 263. The limiter 262 imposes a limit on the output value from the subtractor SU4. When the input value exceeds the upper or lower threshold, the limiter 262 limits the input value to the upper or lower threshold. The threshold of the limiter 262 is different from the threshold of the limiter 252, for example. The gain adjuster 263 multiplies the output value from the limiter 262 by a gain K4. In the transfer function P of the first control object 560, s (s) is constrained to be the transfer function P of the first nominal model NM1 sn Under the condition of (s), the maximum value of the gain K4 of the gain adjuster 263 is determined. The value of the gain K4 is different from the value of the gain K3, for example. The value of the gain K4 is, for example, about 0.1 or more and about 0.8 or less in the manual driving mode. The value of the gain K4 is, for example, about 1 in the automatic driving mode. The value of the gain K4 being about 1 includes the value of the gain K4 being 0.8 or more and about 1 or less. The gain K4 of the gain adjuster 263 may also be switched according to the driving mode of the vehicle V.

[0161] Interference compensation value V d is the differential torque T a The frequency component T aL The disturbance compensation value calculation unit 260 calculates, for example, a value corresponding to the self-aligning torque T actually generated by the first controlled object 560. SAT The value of about half of V is used as the interference compensation value d The self-aligning torque T actually generated by the first controlled object 560 SAT For example, the value of the threshold value of the limiter 262 and the gain K4 of the disturbance compensation value calculation unit 260 is adjusted to the self-aligning torque T calculated in advance in the manual driving mode. SAT The disturbance compensation value V is calculated as a value of about 0.1 times or more and about 0.8 times or less of the magnitude of d The threshold value of the limiter 262 and the gain K4 of the disturbance compensation value calculation unit 260 are adjusted to the self-aligning torque T calculated in advance in the automatic driving mode. SAT The disturbance compensation value V is calculated by taking a value which is approximately 1 times the size of d The disturbance compensation value V calculated in the disturbance compensation value calculation unit 260 is d is the friction compensation value V calculated in the friction compensation value calculation unit 250. f Different values.

[0162] Here, the differential torque T a The frequency component T aL In addition to the automatic return torque TSAT In addition, it also includes the friction force generated by the first controlled object 560, the disturbance torque caused by the looseness generated by the first controlled object 560, and the torque fluctuation generated by the first controlled object 560. Therefore, when the frequency component T is adjusted by the limiter 262 and the gain adjuster 263, aL The interference compensation value V obtained by processing d The compensation value for compensating for at least a portion of the friction force generated by the first controlled object 560 , the disturbance torque caused by the looseness generated by the first controlled object 560 , and the torque fluctuation generated by the first controlled object 560 is also included.

[0163] In order to adjust the first correction torque T used in the model following control of the first model following control unit 230 f1 The friction compensation and disturbance compensation applied in the auxiliary adjustment unit 270 need to pay attention to the stability condition of the model tracking control. This condition is that, according to the small gain theorem described later, the gain in the gain characteristic of the transfer function of the auxiliary adjustment unit 270 constrained to take into account the stability characteristics does not exceed 1. This is derived based on the design conditions of the second filter 232b. In this embodiment, a subtractor SU4 is set in the front stage of the limiter 252 and 262 to apply a subtraction process so that the values ​​of the gains K3 and K4 in the gain adjusters 253 and 263 are 1 at most, and the gain in the gain characteristic is 1 under this condition. In other words, the auxiliary adjustment unit 270 acts as a low-pass filter having a transfer function of 1-Q1(s). Q1(s) is the transfer function of the first filter 232a as a high-pass filter. The auxiliary adjustment unit 270 performs low-pass filtering processing with a transfer function of 1-Q1(s) on the torque output from the second filter 232 b , and adjusts and outputs the processed values ​​in the friction compensation value calculation unit 250 and the disturbance compensation value calculation unit 260 .

[0164] In addition, for example, in both the manual driving mode and the automatic driving mode, the values ​​of the above-mentioned gains K3 and K4 are determined in such a way that the friction component is 100% compensated. Here, the compensation object of the friction compensation value calculation unit 250 is only the friction component, while the compensation object of the interference compensation value calculation unit 260 is all interferences that also include friction components. In the automatic driving mode, for example, it is preferable to compensate for substantially all interferences, so the gain K4 of the interference compensation value calculation unit 260 is substantially 1. In this case, the friction component is also substantially fully compensated by the compensation of the interference compensation value calculation unit 260, so the gain K3 of the friction compensation value calculation unit 250 is zero. On the other hand, in the passive driving mode, it is preferable to retain a portion of the self-aligning torque T SATThe tire reaction force of the disturbance compensation value calculation unit 260 is reduced to make it easier for the steerer to steer the vehicle V, and the friction component is 100% compensated. Therefore, in the manual driving mode, it is preferred that the gain K4 of the disturbance compensation value calculation unit 260 is less than 1, and the friction component not compensated by the disturbance compensation value calculation unit 260 is compensated by the friction compensation value calculation unit 250. For example, in the manual driving mode, when the gain K4 of the disturbance compensation value calculation unit 260 is 0.8, the gain K3 of the friction compensation value calculation unit 250 is set to 0.2, and the friction component of 20% not compensated by the disturbance compensation value calculation unit 260 is compensated by the friction compensation value calculation unit 250.

[0165] The adder AD4 adds the output value from the auxiliary adjustment unit 270 and the output value from the first filter 232a. That is, the adder AD4 adds the friction compensation value V f and interference compensation value V d With frequency component T aM The frequency component T is output from adder AD4. aM , Friction compensation value V f And the interference compensation value V d The first correction torque T calculated by adding f1 The first correction torque T output from the adder AD4 f1 The input fed back to the first controlled object 560, namely, the command torque T rL1 Thus, in the present embodiment, the first model following control unit 230 removes the frequency components lower than the first cutoff frequency Cf1 through the first filter 232a which is a high-pass filter. a , that is, the frequency component T aM Add friction compensation value V f and interference compensation value V d The first correction torque T is generated. f1 .

[0166] The first state feedback unit 280 adjusts the apparent transfer function of the first controlled object 560 to be close to the transfer function P of the first nominal model NM1 according to the output of the first controlled object 560. sn (s) to the command torque T rL1 Feedback state compensation value V s. The apparent transfer function of the first controlled object 560 is, for example, a transfer function of a portion located inside the feedback loop created by the first model tracking control unit 230 when the portion is regarded as a single portion. Specifically, in the present embodiment, the apparent transfer function of the first controlled object 560 refers to a transfer function of the entire portion from the subtractor SU2 to the output of the first controlled object 560, and is a transfer function of a portion that combines the first state feedback unit 280 and the first controlled object 560. In the present embodiment, the first state feedback unit 280 is a transfer function of the first correction torque T f1 The command torque T after correction and before input to the first controlled object 560 rL1 Feedback state compensation value V s .

[0167] State compensation value V s The state compensation value V includes a compensation value for compensating at least a part of the inertial force generated by the first controlled object 560, the viscosity force generated by the first controlled object 560, and the friction force generated by the first controlled object 560. More specifically, the state compensation value V s The state compensation value V includes a compensation value for compensating at least a part of the inertial force generated by the motor 543, the viscous force generated by the motor 543, and the friction force generated by the motor 543. In this embodiment, the state compensation value V s These are compensation values ​​that include the inertial force generated by the motor 543 , the viscous force generated by the motor 543 , and the friction force generated by the motor 543 .

[0168] The first state feedback unit 280 includes an inertia compensator 281, a viscosity compensator 282, and a friction compensator 283. The inertia compensator 281 adjusts the inertia compensator 281 according to the steering angle θ. s , calculates a compensation value for compensating at least a portion of the inertial force generated by the motor 543. The viscosity compensator 282 is adjusted according to the steering angle θ s , calculates a compensation value for compensating at least a portion of the viscous force generated by the motor 543. The friction compensator 283 is configured according to the steering angle θ. s , calculates a compensation value for compensating at least a portion of the friction force generated by the motor 543. In this embodiment, the state compensation value V s The compensation value calculated by the inertia compensator 281, the compensation value calculated by the viscosity compensator 282, and the compensation value calculated by the friction compensator 283 are output to the adder AD3 and added to the first correction torque T f1 Corrected command torque T rL1 Add.

[0169] Next, the control of the first model tracking control unit 230 will be described in further detail. The first model tracking control unit 230 uses the inverse model of the first nominal model NM1 as an internal model, that is, the first inverse nominal model 231 to control the first controlled object 560. In this embodiment, the feedback loop created by the first model tracking control unit 230 can compensate for torque fluctuations and the like depending on the angular velocity of the motor 543.

[0170] The first model tracking control unit 230 is similar in structure to the existing disturbance inference device (disturbance observer), but has different target actions / effects. The existing disturbance inference device infers the disturbance torque by setting the inverse plant model as an internal model to a model close to the first control object 560, and reduces the influence of the disturbance by adding or subtracting the disturbance torque in advance.

[0171] The control of the first model following control unit 230 of the present embodiment uses the transfer function P of the first controlled object 560 to be converted into s (s) The constraint is the transfer function P of the first nominal model NM1 as the internal model. sn For example, if the first nominal model NM1 is defined in a manner that does not have torque fluctuations, the transfer function P of the first controlled object 560 is set to s (s) is constrained to have a characteristic of no torque fluctuation, and as a result, by applying compensation for torque fluctuation, the torque fluctuation can be reduced. In addition, by making the first nominal model NM1 a low inertia model and using the first nominal model NM1 to constrain the first control object 560, the first control object 560 can be treated as a low inertia model. In addition, by making the first nominal model NM1 a low viscosity model and using the first nominal model NM1 to constrain the first control object 560, the first control object 560 can also be treated as a low viscosity model. By performing model tracking control by the first model tracking control unit 230, in addition to compensating for the torque fluctuation of the motor 543, for example, loss torque compensation or motor inertia compensation is also performed. In the above-mentioned equations (16) and (17), by appropriately setting J n and B n , the transfer function P of the first controlled object 560 can be s (s) imparts desired frequency characteristics.

[0172] When the transfer function P of the first controlled object 560 is s (s) and the transfer function P of the first nominal model NM1 sn When the modeling error of (s) is Δ(s), the transfer function P of the first controlled object 560 is s (s) is represented by, for example, the following formula (18).

[0173]

[0174] In addition, the transfer function P of the first controlled object 560 is s (s), that is, the plant characteristics in the model following control of the first model following control unit 230 is not limited to the example of the above-mentioned equation (18), and can be expressed arbitrarily. The transfer function P of the first controlled object 560 is s (s) can be expressed as two inertial systems or by an equation derived by a higher-order approximation.

[0175] The transfer function P of the first controlled object 560 s The gain characteristic of (s) has peaks at two frequency values, for example. The modeling error Δ(s) appears, for example, near the peak with the higher frequency of the two peaks in the gain characteristic of the first controlled object 560. Therefore, Fig.17 As shown in FIG. 1 , the inverse of the modeling error Δ(s) 1 / Δ(s) has a bottom in a relatively high frequency region. Fig.17 In the example, the modeling error Δ(s) is expressed as an absolute value. When the modeling error Δ(s) increases, the transfer function P of the first controlled object 560 s (s) and the transfer function P of the first nominal model NM1 sn As the deviation of (s) increases, the control of the first controlled object 560 by the first model tracking control unit 230 using the first nominal model NM1 becomes unstable. Therefore, in the region where the modeling error Δ(s) is relatively small, the gain of the complementary sensitivity function T(s) is set to 1, and the first controlled object 560 is constrained to the first nominal model NM1, thereby enabling the first controlled object 560 to be stably and appropriately controlled. The transfer function P of the first nominal model NM1 can be adjusted to sn J in (s) n and B n The frequency characteristics of the modeling error Δ(s) are adjusted. The frequency band in which the gain of the complementary sensitivity function T(s) is 1 can be adjusted by adjusting the first cutoff frequency Cf1 and the second cutoff frequency Cf2. Thus, the gain of the complementary sensitivity function T(s) can be adjusted to 1 in the frequency band in which the modeling error Δ(s) is small.

[0176] exist Fig.17 , 1 / Δ(s) is relatively high in the frequency band below the second cutoff frequency Cf2, and decreases sharply in the frequency band higher than the second cutoff frequency Cf2. The model following control that constrains the first controlled object 560 to the first nominal model NM1 can be stably performed in the range where 1 / Δ(s) is greater than 1, that is, greater than 0 dB. Therefore, Fig.17As shown, by adjusting in a frequency band where the gain of the complementary sensitivity function T(s) is 1 in a manner such that 1 / Δ(s) is greater than 1, when the gain of the complementary sensitivity function T(s) is 1, the first control object 560 can be constrained to the first nominal model NM1 and controlled stably and appropriately.

[0177] For example, in order to expand the frequency band in which the first controlled object 560 can be constrained to the first nominal model NM1 and stably and appropriately controlled, as long as 1 / Δ(s) is not less than 1, that is, Fig.17 In the frequency band where the curve representing 1 / Δ(s) intersects with the horizontal axis at a low frequency, the second cutoff frequency Cf2 can be increased. However, when the second cutoff frequency Cf2 is too high, in the frequency band higher than the second cutoff frequency Cf2, although 1 / Δ(s) becomes lower, the gain of the complementary sensitivity function T(s) is still high, and the control may become unstable. In contrast, in the present embodiment, since the order of the second filter 232b as a low-pass filter is set to be three or more, the gain of the complementary sensitivity function T(s) can be sharply reduced in the region where the frequency is higher than the second cutoff frequency Cf2. Thus, even if the second cutoff frequency Cf2 is made relatively high, the gain of the complementary sensitivity function T(s) can be immediately reduced in the frequency band higher than the second cutoff frequency Cf2, so that the control of the first control object 560 can be suppressed from becoming unstable.

[0178] The robust stability of the first model tracking control unit 230 is ensured when the small gain theorem expressed by the following equation (19) holds true between the complementary sensitivity function T(s) and the modeling error Δ(s).

[0179]

[0180] As described above, in order to perform model tracking control using the first nominal model NM1 in the first model tracking control unit 230, the complementary sensitivity gain GT of the complementary sensitivity function T(s) only needs to be approximately 1, but if robust stability is considered, the above-mentioned formula (19) must be satisfied. As can be seen from this, it is impossible to take into account both making the complementary sensitivity gain GT approximately 1 in all frequency bands and formula (19), and it is impossible to take into account both the suppression of interference and the like by the first model tracking control unit 230 and robust stability.

[0181] like Fig.17 As shown, in the low frequency region FA1 where the frequency f is lower than the first cutoff frequency Cf1, the complementary sensitivity gain GT of the complementary sensitivity function T(s) is also less than 1. In the region where the complementary sensitivity gain GT of the complementary sensitivity function T(s) is less than 1, the command torque T rL1As described above, in the high frequency region FA2, which is an area with a frequency higher than the second cutoff frequency Cf2, the complementary sensitivity gain GT of the complementary sensitivity function T(s) is greatly reduced, and the first correction torque T from the first model tracking control unit 230 is obtained. f1 The state in which there is almost no feedback to the input of the first controlled object 560. On the other hand, in the low frequency region FA1, the complementary sensitivity gain GT of the complementary sensitivity function T(s) is set to a certain value, and the first correction torque T f1 Feedback to the input of the first controlled object 560. In the low-frequency region FA1, the compensation value generated in the auxiliary adjustment unit 270 is fed back to the input of the first controlled object 560 according to the complementary sensitivity gain GT of the complementary sensitivity function T(s).

[0182] The control device 100 performs torque control in the first auxiliary control unit 210, the second auxiliary control unit 220, and the vehicle stabilization control unit 240 for the low-frequency torque signal lower than the first cutoff frequency Cf1, and performs control to make the angular velocity substantially zero for the high-frequency disturbance higher than the second cutoff frequency Cf2, thereby stabilizing the steering so that the steering wheel 521 is not removed. In order to achieve this purpose, the control device 100 performs the first auxiliary control unit 210, the second auxiliary control unit 220, and the vehicle stabilization control unit 240 to reduce the high-frequency gain of the torque control and the first model tracking control unit 230 to adjust the transfer function P of the first control object 560 s (s) Constraint to a characteristic of reducing high frequency gain The reason for performing the latter process is to prevent the first controlled object 560 from reacting to the disturbance when the disturbance is input to the first controlled object 560 .

[0183] When the steering angle θ is input h The transfer function of the portion from the subtractor SU1 to the adder AD1 to which the output of the disturbance sensitivity control unit 290 is input is C2(s), and the disturbance torque T is the disturbance sensitivity characteristic. d (s), namely, the first correction torque T f1 When the ratio of the disturbance input to the first controlled object 560 is set as a variable parameter m, the disturbance torque T d (s) to steering torque T h The transfer characteristic of (s) is expressed as shown in the following equation (20) using the complementary sensitivity function T(s), and the complementary sensitivity function T(s) is expressed as shown in the following equation (21).

[0184]

[0185] According to the above formula (20), if the complementary sensitivity function T(s) is 1, the interference is completely suppressed, and if the complementary sensitivity function T(s) is less than 1, at least a part of the interference is transmitted. Therefore, by dividing the interference to be transmitted and the interference to be suppressed in the frequency region and performing frequency shaping on the complementary sensitivity function T(s) accordingly, the interference sensitivity design for each frequency region can be performed. The variable parameter m in the above formulas (20) and (21) is related to the first correction torque T f1 Disturbance torque T d The proportion of compensation is equal, T f1 =mT d For example, if the variable parameter m is 0.5, then the first correction torque T f1 Interference torque T d 50% compensation is performed. In the present embodiment, when the assist control of the first assist control unit 210 is not performed, the variable parameter m is greater than 0.1 and less than 0.8. When the assist control of the first assist control unit 210 is performed, the variable parameter m is approximately 1. The variable parameter m being approximately 1 includes the variable parameter m being greater than 0.8 and less than 1.

[0186] When the transfer function P of the first controlled object 560 is s When (s) is set to the above formula (18), it becomes C2(s)=K tor +K ass Therefore, the steady-state gain T(0) of the complementary sensitivity function T(s) when s=0 is expressed as the following equation (22) according to the above equation (21). That is, when the spring constant of the torsion bar 546 is set to K tor , the self-aligning torque T generated by the tires 529A and 529B of the vehicle V SAT With respect to the steering angle θ as the rotation angle of the output shaft 524b s The slope of SAT , the auxiliary torque T ass Relative to input torque T ad The slope is set to K ass , the steady-state gain is set to T(0), the disturbance input to the first controlled object 560, that is, the first correction torque T f1 With the interference torque T d When the ratio, that is, the variable parameter is set to m, the following formula (22) holds.

[0187]

[0188] When the steering wheel 521 is at the center position or near the center position and the vehicle V is traveling at a speed V v In the case of high steady state, the auxiliary gain K assThe spring constant K of the torsion bar 546 is close to zero. tor Sufficiently smaller than the automatic return torque gain K SAT Therefore, when the steering wheel 521 is at the center position or near the center position and the vehicle V is traveling at a speed V v In the steady-state state, the steady-state gain T(0) becomes close to the first correction torque T according to the above formula (22). f1 With the interference torque T d (s) is the value of the variable parameter m. The steady-state gain T(0) of the complementary sensitivity function T(s) represented by the above equation (22) is greater than 0.1. In the present embodiment, the steady-state gain T(0) is greater than 0.3. The steady-state gain T(0) is, for example, less than 0.5. The steady-state gain T(0) is the minimum value of the complementary sensitivity gain GT in the low-frequency area FA1.

[0189] Conventionally, for example, the complementary sensitivity function T(s) in the low-frequency region FA1 is Fig.17 In this embodiment, by performing the model tracking control of the first model tracking control unit 230, the steady-state gain T(0) of the complementary sensitivity function T(s) can be made as shown in the above equation (22), and the complementary sensitivity function T(s) can be shaped with respect to the frequency f as Fig.17 The waveform is as shown by the solid line.

[0190] In this embodiment, Fig.17 The low-frequency region FA1 of the waveform of the complementary sensitivity gain GT of the complementary sensitivity function T(s) shown in FIG. 1 is generated by the first filter 232a, the auxiliary adjustment unit 270, and the adder AD4 in the first model tracking control unit 230. More specifically, the frequency component T output from the first filter 232a as a high-pass filter is converted into the low-frequency region FA1. aM The friction compensation value V output from the auxiliary adjustment unit 270 functioning as a low-pass filter is f and interference compensation value V d The value at which the frequency f in the low-frequency part TFA1 becomes zero is the value of s=0 in the complementary sensitivity function T(s), which is the steady-state gain T(0) represented by the above equation (22).

[0191] like Fig.17 As shown, the first cut-off frequency Cf1 is higher than the first resonance frequency f yaw High. The first resonance frequency f yaw The natural vibration frequency f of the yaw rate γ of the vehicle V γ That is, the lower limit ratio of the frequency band in which the complementary sensitivity gain GT becomes 1 is equal to the natural vibration frequency f of the yaw rate γ of the vehicle V.γ Equal first resonance frequency f yaw High. The natural vibration frequency f at the yaw rate γ γ is not constrained by the second model tracking control unit 241 as the parameter f r In the case of yaw For example, it is about 1 Hz or more and 1.5 Hz or less. In the present embodiment, as described above, the natural frequency f of the yaw rate γ of the vehicle V can be γ Constrained to be the desired parameter f r , so the first resonance frequency f yaw It is about 2 Hz or more and 4 Hz or less.

[0192] Fig.17 The second resonance frequency f st is the resonant frequency of the steering mechanism 530. More specifically, the second resonant frequency f st The inertia and self-aligning torque T of the steering mechanism 530 are generated. SAT The resonant frequency of the mode formed by the spring elements. The second resonant frequency f st Compared with the first resonance frequency f yaw The second resonance frequency f is higher than the first cutoff frequency Cf1 which is the lower limit of the frequency band in which the complementary sensitivity gain GT is 1. st For example, it is about 3 Hz or more and 5 Hz or less. The second resonance frequency f st The complementary sensitivity gain GT under the first resonance frequency f yaw The complementary sensitivity gain GT is high. The second resonance frequency f st The complementary sensitivity gain GT under the condition of is greater than or equal to 0.5 and less than 1. In this embodiment, the second resonance frequency f st The complementary sensitivity gain GT is above 0.8.

[0193] In this embodiment, Fig.17 The high-frequency region FA2 of the waveform of the complementary sensitivity gain GT of the complementary sensitivity function T(s) shown, that is, the high-frequency portion TFA2 is generated by the second filter 232 b in the first model tracking control unit 230 .

[0194] The low-frequency region FA1 of the waveform of the complementary sensitivity gain GT of the complementary sensitivity function T(s), i.e., the low-frequency portion TFA1, can also be produced by a phase lead compensator. Specifically, the first filter 232a can also be a phase lead compensator. In this case, the complementary sensitivity function T(s) is a function including the transfer function of the second filter 232b as a low-pass filter and the transfer function of the phase lead compensator. Even in this case, the complementary sensitivity gain GT of the complementary sensitivity function T(s) can be appropriately adjusted to the above-mentioned numerical range, which can achieve Fig.17 The waveform of the complementary sensitivity gain GT is as shown.

[0195] When the low-frequency region FA1 of the waveform of the complementary sensitivity gain GT of the complementary sensitivity function T(s), i.e., the low-frequency portion TFA1, is produced by a phase lead compensator, the transfer function F(s) of the phase lead compensator is expressed by the following equation (23).

[0196]

[0197] Where s is the Laplace transform, ω a ,ω b This is a parameter that is appropriately set according to the ratio between the assist control by the first assist control unit 210 and the assist control by the second assist control unit 220 .

[0198] The variable parameter m is the steady-state gain F(0) of the above equation (23). That is, m=ω a / ω b Therefore, in ω a =ω b In the case of the self-aligning torque T, the maximum compensation can be made. SAT The disturbance torque T d Specifically, in ω a =ω b In the case of d When the first assist control unit 210 performs lane keeping control, the compensation is performed by about 100%. a =ω b Or a ≈ω b , preferably m is set to 1 or a value close to 1 to maximize the compensation of the disturbance torque T d When the assist control of the first assist control unit 210 is not performed and only the assist control of the second assist control unit 220 is performed, if the disturbance torque T transmitted to the steering operator is d Assuming the ratio of is n, then m = 1-n holds. Thus, by finding the variable parameter m, the parameter ω can be calculated. a ,ωb .

[0199] In the case of shared control in which the assist control by the first assist control unit 210 and the assist control by the second assist control unit 220 are performed simultaneously, the steering torque T h Adaptively adjust the parameter ω a In this case, the parameter ω a It is expressed by the following formula (24).

[0200]

[0201] Among them, m ＊ is the compensation disturbance torque T when only the assist control of the second assist control unit 220 is executed without executing the assist control of the first assist control unit 210. d The constant of proportionality, T h ＊ The steering torque is obtained when the assist control of the first assist control unit 210 is not performed and only the assist control of the second assist control unit 220 is performed. ＊ It is a constant in the range of 0.1 to 0.8.

[0202] The variable parameter m changes according to the second gain K2. The variable parameter m is given by m=m ＊ ×K2+K1. When the assist control of the first assist control unit 210 is not performed, the second gain K2 is 1. When the second gain K2 is 1, the first gain K1 is zero, and the variable parameter m is a constant m. ＊ , that is, 0.1 or more and 0.8 or less. In addition, according to the relationship K1=1-K2, if 1-m ＊ Set to m ＊＊ , then the variable parameter m is expressed as m = 1-m ＊＊ × K2. According to this formula, the larger the second gain K2, the smaller the variable parameter m, and the smaller the second gain K2, the larger the variable parameter m. That is, the variable parameter m and the second gain K2 are complementary to each other. In this embodiment, the variable parameter m is equal to the above-mentioned gain K4.

[0203] According to the above formula (22), the larger the variable parameter m is, the larger the steady-state gain T(0) of the complementary sensitivity function T(s) is. In the present embodiment, the steady-state gain T(0) of the complementary sensitivity function T(s) when the first auxiliary control unit 210 performs auxiliary control, i.e., lane keeping control is greater than the steady-state gain T(0) of the complementary sensitivity function T(s) when the first auxiliary control unit 210 does not perform lane keeping control.

[0204] In the control method for controlling the steering mechanism 530 mounted on the vehicle V by the control device 100, the lane keeping control includes the following steps: calculating a target value of the yaw rate γ of the vehicle V, that is, a yaw rate target value γ, based on input from the camera device 400. r and the lateral offset y of the vehicle V of ; According to the yaw rate target value γ r The yaw rate command torque T is generated γ ; According to the lateral offset y of The lateral offset command torque T is generated y In the yaw rate adjustment unit 213b, the yaw rate command torque T is adjusted according to the frequency f γ and adjusting the lateral offset command torque T according to the frequency f in the lateral offset adjustment unit 214b y .

[0205] In addition, the control method of controlling the steering mechanism 530 mounted on the vehicle V by the control device 100 includes the following steps: generating the first command torque T by performing lane keeping control to keep the vehicle V in the lane L. LKA According to the steering torque T input from the steering wheel 521 of the vehicle V h The second command torque T is generated r ; According to the first command torque T multiplied by the first gain K1 LKA The second command torque T multiplied by the second gain K2 r To calculate the command torque T rL1 Execute the command torque T generated based on the output of the first control object 560 including the motor 543 provided in the steering mechanism 530 and the first nominal model NM1 based on the structure of the first control object 560 rL1 The first correction torque T for correction f1 model tracking control; and by the model tracking control, in a frequency band where the gain in the gain characteristic of the complementary sensitivity function T(s) with respect to the modeled error Δ(s) between the first controlled object 560 and the first nominal model NM1, i.e., the complementary sensitivity gain GT, is approximately 1, the transfer function P of the first controlled object 560 is s (s) is constrained to be the transfer function P of the first nominal model NM1 ns (s).

[0206] According to the present embodiment, the control device 100 includes a first auxiliary control unit 210 capable of executing lane keeping control to keep the vehicle V in the lane L. The first auxiliary control unit 210 includes a vehicle state calculation unit 211 that calculates a target value of the yaw rate γ of the vehicle V, that is, a yaw rate target value γ, based on input from the camera device 400. r and the lateral displacement y of the vehicle Vof ; The yaw rate control unit 213, which is based on the yaw rate target value γ r The yaw rate command torque T is generated γ And a lateral offset control unit 214, which according to the lateral offset y of The lateral offset command torque T is generated y The yaw rate control unit 213 has a function of adjusting the yaw rate command torque T according to the frequency f. γ The lateral deviation control unit 214 has a yaw rate adjustment unit 213b. The lateral deviation control unit 214 has a lateral deviation command torque T adjusted according to the frequency f. y The transfer function C of the yaw rate adjustment unit 213b in the first frequency band fb1 is γ The gain of (s) is lower than the transfer function C of the yaw rate adjustment unit 213b in the second frequency band fb2 higher than the first frequency band fb1. γ The transfer function C of the lateral offset adjustment unit 214b in the second frequency band fb2 is y The gain of (s) is lower than the transfer function C of the lateral offset adjustment unit 214b in the first frequency band fb1. y (s) gain.

[0207] Here, the yaw rate γ is adjusted by rotating the steering wheel 521 to tilt the traveling direction of the vehicle V, while the lateral deviation y of The adjustment is made by maintaining the state of the traveling direction tilted to a certain extent for a certain period of time. Therefore, when adjusting the yaw rate γ, the frequency of steering the steering wheel 521 is easier to be than when adjusting the lateral deviation y. of Therefore, by reducing the transfer function C of the yaw rate adjustment unit 213b in the relatively low first frequency band fb1, γ The gain of (s) is reduced to reduce the transfer function C of the lateral offset adjustment unit 214b in the relatively high second frequency band fb2. y The gain of (s) can easily control the yaw rate γ and lateral offset y in the preferred frequency band respectively. of Specifically, in the relatively high second frequency band fb2, the yaw rate command torque T for adjusting the yaw rate γ is easily increased. γ The influence of the first frequency band fb1 is relatively low, and it is easy to increase the adjustment of the lateral offset y of The lateral offset command torque T y Thus, by enhancing the control band of the yaw rate γ and enhancing the lateral offset y of The control band of the control is separated, and the yaw rate γ and lateral deviation y can be controlled simultaneously with high precision. ofThus, in the lane keeping control, the accuracy of maintaining the vehicle V in the lane L can be improved. In the present embodiment, the control device 100 has a yaw rate γ and a lateral offset y. of These two feedback units can adjust various parameters with high precision.

[0208] According to the present embodiment, when the transfer function of the yaw rate adjustment unit 213b is set to C γ (s) Let the transfer function of the lateral offset adjustment unit 214b be C y (s), let K be a constant that is approximately 1 γy When C γ (s) = K γy -C y (s) holds. Therefore, the transfer function C of the yaw rate adjustment unit 213b can be made γ (s) and the transfer function C of the lateral offset adjustment unit 214b y (s) are in a substantially complementary relationship with each other. As a result, the yaw rate command torque T can be divided more appropriately. γ The frequency band in which the influence becomes greater and the lateral offset command torque T y Therefore, the yaw rate γ and the lateral offset y can be more appropriately controlled according to the frequency band. of Therefore, in the lane keeping control, the accuracy of keeping the vehicle V within the lane L can be further improved.

[0209] According to the present embodiment, the control device 100 includes a vehicle stabilization control unit 240. The vehicle stabilization control unit 240 uses the actual steering angle θ of the tires 529A and 529B of the vehicle V to control the vehicle stabilization. t The transfer function G of the plant model, that is, the second controlled object 580, which takes the yaw rate γ as an input and outputs θ γ (s) The transfer function P of the second nominal model NM2 is constrained to be specified nv The vehicle stabilization control unit 240 includes a second model tracking control unit 241 that performs model tracking control. The second model tracking control unit 241 is configured to adjust the transfer function G of the second controlled object 580 to the frequency band where the gain of the complementary sensitivity function to the modeling error between the second controlled object 580 and the second nominal model NM2 is approximately 1. θ γ (s) is constrained to be the transfer function P of the second nominal model NM2 nv (s). The transfer function P of the second nominal model NM2 nv (s) includes the natural vibration frequency f corresponding to the yaw rate γ γ The parameter f nThe yaw rate control unit 213 has a yaw rate target value γ r The yaw rate phase adjustment unit 213c is configured to adjust the phase of the yaw rate phase. The transfer function of the yaw rate phase adjustment unit 213c includes a transfer function P of the second nominal model NM2. nv The natural vibration frequency f in (s) and the yaw rate γ γ The equivalent parameter f n Therefore, by the model following control performed by the second model following control unit 241, the characteristics of the vehicle V can be constrained to the second nominal model NM2, and the natural vibration frequency f in the second nominal model NM2 and the yaw rate γ can be γ The equivalent parameter f n Adjust to the desired value, i.e. parameter f r As a result, the driving stability of the vehicle V can be further improved.

[0210] According to the present embodiment, the control device 100 has a steering torque T as a steering input value input from the steering wheel 521 of the vehicle V. h The second command torque T is generated as the second input value to the vehicle stabilization control unit 240. r The first assist control unit 210 generates a first command torque T as a first input value. LKA The second assist control unit 220 receives the first command torque T multiplied by the first gain K1. LKA1 and the steering torque T multiplied by the second gain K2 h1 The first gain K1 and the second gain K2 are variable values. When the first gain is set to K1 and the second gain is set to K2, K1=1-K2 holds. Therefore, by adjusting the value of the second gain K2, the first command torque T input from the first auxiliary control unit 210 to the second auxiliary control unit 220 can be changed. LKA1 Thus, in the shared control in which the assist control of the first assist control unit 210 and the assist control of the second assist control unit 220 are performed simultaneously, the steering torque T h The control amount of the assist control by the first assist control unit 210 is adjusted by adjusting the size of the assist control, etc.

[0211] According to the present embodiment, the first command torque T LKA1The input is also input to the vehicle stabilization control unit 240. Therefore, the same input as the input mechanically transmitted to the steering mechanism 530 by the helmsman steering the steering wheel 521 can also be input from the first auxiliary control unit 210. As a result, the auxiliary control of the first auxiliary control unit 210 can be made close to the case where the helmsman steers the steering wheel 521. Therefore, when the auxiliary control is performed by the first auxiliary control unit 210, the discomfort caused by the helmsman can be reduced.

[0212] Conventionally, lane keeping control needs to function within a safer torque range, so it is necessary to adjust auxiliary functions for lane keeping control, which takes time. The safer torque range refers to the steering torque T that can be easily corrected according to the intention of the steersman even if an abnormal output is output due to lane keeping control. h In addition, in the past, if the torque used for lane keeping control, that is, the control amount of lane keeping control, is increased, the steersman will feel uncomfortable, so it is difficult to increase the control amount of lane keeping control, and sometimes the accuracy of lane keeping control cannot be fully improved.

[0213] To solve the above problem, according to the present embodiment, the control device 100 includes a disturbance sensitivity control unit 290, which receives a first command torque T multiplied by a first gain K1 as a first input value. LKA1 and the second command torque T as the second input value multiplied by the second gain K2 r The calculated command torque T rL1 The disturbance sensitivity control unit 290 includes a first model tracking control unit 230 that generates a response to the command torque T based on the output of the first control object 560 including the motor 543 provided in the steering mechanism 530 and a first nominal model NM1 based on the structure of the first control object 560. rL1 The first correction torque T for correction f1 The first model tracking control unit 230 is configured to adjust the transfer function P of the first controlled object 560 to a frequency band in which the gain of the complementary sensitivity function T(s) with respect to the modeled error Δ(s) between the first controlled object 560 and the first nominal model NM1, that is, the complementary sensitivity gain GT, is approximately 1. s (s) is constrained to be the transfer function P of the first nominal model NM1 ns (s) The complementary sensitivity function T(s) includes a variable parameter m that changes according to the second gain K2.

[0214] Therefore, the self-aligning torque T can be compensated by the model following control of the first model following control unit 230 of the disturbance sensitivity control unit 290. SATThus, when the first auxiliary control unit 210 performs lane keeping control, even if the control amount of the first auxiliary control unit 210 is reduced, the lane keeping control can be performed with high accuracy. Therefore, the control amount of the first auxiliary control unit 210 can be reduced to reduce the discomfort felt by the steersman from the steering wheel 521, and the accuracy of the lane keeping control can be improved. In addition, since the disturbance can be compensated by the model tracking control, the auxiliary function adjustment for the lane keeping control mentioned above is not required even if the control amount of the first auxiliary control unit 210 is reduced. In addition, the complementary sensitivity function T(s) in the first model tracking control unit 230 includes a variable parameter m that changes according to the second gain K2. Therefore, the proportion of the disturbance compensated by the first model tracking control unit 230 is adjusted according to the change of the second gain K2. Thus, for example, when the second gain K2 becomes smaller and the lane keeping control of the first auxiliary control unit 210 becomes stronger, the variable parameter m can be changed to increase the compensation ratio of the disturbance. Therefore, the compensation ratio of the disturbance can be adjusted according to the ratio of the control of the first auxiliary control unit 210 and the control of the second auxiliary control unit 220. Therefore, the accuracy of the lane keeping control can be further improved while further reducing the discomfort felt by the steersman from the steering wheel 521.

[0215] In addition, according to the present embodiment, the first gain K1 when the first auxiliary control unit 210 performs lane keeping control is greater than the first gain K1 when the first auxiliary control unit 210 does not perform lane keeping control. The steady-state gain T(0) of the complementary sensitivity function T(s) when the first auxiliary control unit 210 performs lane keeping control is greater than the steady-state gain T(0) of the complementary sensitivity function T(s) when the first auxiliary control unit 210 does not perform lane keeping control. Therefore, when the first auxiliary control unit 210 performs lane keeping control, the proportion of interference compensated by the first model tracking control unit 230 can be increased compared to when the lane keeping control is not performed. As a result, the accuracy of the lane keeping control can be further improved while reducing the control amount of the first auxiliary control unit 210.

[0216] In addition, according to the present embodiment, the larger the variable parameter m is, the larger the steady-state gain T(0) of the complementary sensitivity function T(s) is. The variable parameter m and the second gain K2 are in a complementary relationship with each other. Therefore, the larger the ratio of the lane keeping control of the first auxiliary control unit 210 relative to the control of the second auxiliary control unit 220 is, the greater the compensation ratio of the disturbance sensitivity control unit 290 to the disturbance can be continuously increased. Thus, the accuracy of the lane keeping control can be more appropriately improved while the control amount of the first auxiliary control unit 210 is appropriately reduced according to the ratio of the control of the first auxiliary control unit 210. In addition, the auxiliary control of the first auxiliary control unit 210, that is, the lane keeping control and the auxiliary control of the second auxiliary control unit 220 can be adjusted linearly and continuously. Thus, in the shared control of the auxiliary control of the first auxiliary control unit 210 and the auxiliary control of the second auxiliary control unit 220, the switching characteristics of the control can be suppressed from becoming nonlinear, and the discomfort of the steersman can be reduced.

[0217] According to the present embodiment, the second assist control unit 220 controls the steering torque T h The calculated input torque T ad , generating a self-aligning torque T for the tires 529A and 529B of the vehicle V SAT The auxiliary torque T that compensates at least part of ass According to the assist torque T ass The second command torque T is calculated as the second input value. r The variable parameter m is the first correction torque T f1 The ratio of the disturbance input to the first controlled object 560. When the spring constant of the torsion bar 546 is K tor , the self-aligning torque T generated by the tires 529A and 529B of the vehicle V SAT With respect to the steering angle θ as the rotation angle of the output shaft 524b s The inclination is set to K SAT , the auxiliary torque T ass Relative to input torque T ad The slope is set to K ass When the steady-state gain of the complementary sensitivity function T(s) is set to T(0) and the variable parameter is set to m, the above equation (22) holds. By expressing the steady-state gain T(0) of the complementary sensitivity function T(s) by equation (22) including the variable parameter m, the compensation ratio of the interference can be further easily adjusted according to the change of the second gain K2.

[0218] In addition, in the present embodiment, the yaw rate command value generated in the yaw rate control unit 213 and the lateral offset command value generated in the lateral offset control unit 214 are not limited to torques, but may be angles. When the yaw rate command value and the lateral offset command value are angles, the first input value output from the first auxiliary control unit 210 may be torque or angles. When the first input value output from the first auxiliary control unit 210 is an angle, the input value input to the second auxiliary control unit 220 is also an angle. In this case, the input value input to the vehicle stabilization control unit 240 is also an angle.

[0219] <Second embodiment>

[0220] like Fig.19 As shown, the configuration of the controller 201A of the processor 200A of the control device 100A of the lane keeping system 1100A of this embodiment is different from that of the first embodiment. In this embodiment, the steering torque T output from the torque conversion unit 223 h The second assist control unit 220A has the following input values: h The second assist control unit 220A is the same as the second assist control unit 220 of the first embodiment except for this point. The second command torque T outputted from the second assist control unit 220A is r The second gain adjustment unit 620A has a second command torque T output from the second assist control unit 220A. r The second gain adjustment unit 620A is the same as the second gain adjustment unit 620 of the first embodiment except for this point. r The second command torque T is multiplied by the second gain K2. r1 , and the second command torque T r1 The signal is output to the vehicle stabilization control unit 240A.

[0221] In the present embodiment, the first command torque T outputted from the first gain adjustment unit 610 is LKA1 The first command torque T is input only to the vehicle stabilization control unit 240A. LKA1 and the second command torque T r1 The other configuration of the vehicle stabilization control unit 240A is the same as that of the vehicle stabilization control unit 240 in the first embodiment.

[0222] In the present embodiment, the vehicle stabilization control unit 240A receives the first command torque T 240A as a first input value independently of each other. LKA1 and the second command torque T as the second input valuer1 Therefore, the output from the first auxiliary control unit 210 adjusted by the first gain K1 and the output from the second auxiliary control unit 220A adjusted by the second gain K2 can be input to the vehicle stabilization control unit 240A independently of the output of the other. This makes it easy to adjust the control amount of each auxiliary control unit separately.

[0223] In this specification, “the first input value and the second input value are input independently of each other to the vehicle stabilization control unit” means, for example, that the first input value and the second input value input to the vehicle stabilization control unit are calculated independently of the other input value.

[0224] The other configurations of the control device 100A are the same as those of the control device 100 in the first embodiment. The other configurations of the lane keeping system 1100A are the same as those of the lane keeping system 1100 in the first embodiment.

[0225] In addition, in the present embodiment, the first input value output from the first auxiliary control unit 210 may also be an angle. In this case, the first input value may be input to the vehicle stabilization control unit 240A while maintaining the angle, or may be input to the vehicle stabilization control unit 240A after being converted into torque. When the first input value is input to the vehicle stabilization control unit 240A while maintaining the angle, the second input value output from the second auxiliary control unit 220A and input to the vehicle stabilization control unit 240A is also an angle.

[0226] <Third embodiment>

[0227] like Fig. 20 As shown, in the control device 100B of the present embodiment, the yaw rate control unit 1213 is different from the yaw rate control unit 213 in the first embodiment and does not include a yaw rate phase adjustment unit 213c. In the present embodiment, the yaw rate target value γ outputted from the yaw rate adjustment unit 213b is r2 is input to the torque conversion unit 213d and converted into the yaw rate command torque T γ The other configurations of the yaw rate control unit 1213 are the same as those of the yaw rate control unit 213 in the first embodiment.

[0228] In this embodiment, the transfer function P of the second nominal model NM2 is nv (s) is represented by, for example, the following formula (25).

[0229]

[0230] Where s is the Laplace transform, f r is the natural vibration frequency f that is related to the yaw rate γ γThe expected parameters are equivalent to the parameters G θ γ (0) is the actual steering angle θ of the tires 529A and 529B of the vehicle V. t The transfer function P of the second nominal model NM2 in this embodiment is nv (s) In addition to the transfer function P of the second nominal model NM2 in the first embodiment nv Parameter f of (s) n is replaced by parameter f r In addition to this point, the transfer function P of the second nominal model NM2 in the first embodiment is different from that of the first embodiment. nv (s)Same.

[0231] In this embodiment, the second model following control unit 241 performs a control operation by converting the transfer function G of the second controlled object 580 into θ γ (s) is constrained to have a natural vibration frequency f as a function of the yaw rate γ γ The expected parameter f r The model following control of the second nominal model NM2 can make the transfer function G of the second controlled object 580 θ γ The natural frequency f of the yaw rate γ in (s) γ That is, in the present embodiment, the second model tracking control unit 241 adjusts the transfer function P of the second nominal model NM2 to nv The natural vibration frequency f in (s) and the yaw rate γ γ The equivalent parameter f r , to adjust the transfer function G of the second controlled object 580 as the plant model θ γ The natural frequency f of the yaw rate γ in (s) γ As a result, the driving stability of the vehicle V can be further improved.

[0232] The other structures of the control device 100B are the same as those of the control device 100 in the first embodiment. In addition, the structure of the control device 100B in this embodiment can also be applied to the control device 100A in the second embodiment.

[0233] The present invention is not limited to the above-mentioned embodiments, and other structures and other methods can also be adopted within the scope of the technical concept of the present invention. The first frequency band is not particularly limited. The second frequency band is not particularly limited as long as it is a frequency band higher than the first frequency band. The transfer function of the yaw rate adjustment unit and the transfer function of the lateral offset adjustment unit may not be complementary to each other. The variable parameter can be any variable parameter as long as it changes according to the second gain. When performing lane keeping control, the variable parameter and the second gain may not be complementary to each other.

[0234] In addition, the present technology can adopt the following structures.

[0235] [1] A control device for controlling a steering mechanism mounted on a vehicle, wherein the control device comprises: a first auxiliary control unit capable of executing lane keeping control for maintaining the vehicle within a lane and generating a first input value; a second auxiliary control unit capable of generating a second input value based on a steering input value input from a steering wheel of the vehicle; and a disturbance sensitivity control unit to which is input a command value calculated based on the first input value multiplied by a first gain and the second input value multiplied by a second gain, wherein the first gain and the second gain are variable values, and when the first gain is set to K1 and the second gain is set to K2, K1=1-K2 holds, so The disturbance sensitivity control unit includes a first model tracking control unit, which generates a correction value for correcting the command value based on the output of the control object including the motor provided in the steering mechanism and a first nominal model based on the structure of the control object. The first model tracking control unit is configured to constrain the transfer function of the control object to be the transfer function of the first nominal model in a frequency band in which the gain in the gain characteristics of the complementary sensitivity function with respect to the modeled error between the control object and the first nominal model, i.e., the complementary sensitivity gain, is approximately 1, and the complementary sensitivity function includes a variable parameter that changes according to the second gain.

[0236] [2] A control device according to [1], wherein the first gain when the first auxiliary control unit performs the lane keeping control is greater than the first gain when the first auxiliary control unit does not perform the lane keeping control, and the steady-state gain of the complementary sensitivity function when the first auxiliary control unit performs the lane keeping control is greater than the steady-state gain of the complementary sensitivity function when the first auxiliary control unit does not perform the lane keeping control.

[0237] [3] A control device according to [1] or [2], wherein the larger the variable parameter is, the larger the steady-state gain of the complementary sensitivity function is, and the variable parameter and the second gain are complementary to each other.

[0238] [4] A control device according to any one of [1] to [3], wherein the steering mechanism comprises: an input shaft connected to a steering wheel steered by a steersman; an output shaft connected to the input shaft via a torsion bar; and the motor connected to the output shaft, wherein the second auxiliary control unit generates an auxiliary torque for compensating for at least a portion of the self-aligning torque generated by the tires of the vehicle based on the input torque calculated based on the torsion bar torque generated by the torsion bar, and the second input value is calculated based on the auxiliary torque, and the variable parameter is a ratio of the correction value to the disturbance input to the control object, and when the spring constant of the torsion bar is set to K tor , the slope of the self-aligning torque generated by the tire of the vehicle with respect to the steering angle as the rotation angle of the output shaft is set to K SAT , the slope of the assist torque relative to the input torque is set to K ass , when the steady-state gain of the complementary sensitivity function is set to T(0) and the variable parameter is set to m, the following equation holds:

[0239]

[0240] [5] A control device according to any one of [1] to [4], wherein the control device has a vehicle stabilization control unit that constrains a transfer function of a device model that uses an actual steering angle of the vehicle's tires as an input and a yaw rate of the vehicle as an output to be a transfer function of a second nominal model through model tracking control, the vehicle stabilization control unit having a second model tracking control unit that performs model tracking control, the second model tracking control unit being configured to constrain the transfer function of the device model to be a transfer function of the second nominal model in a frequency band where a gain in a gain characteristic of a complementary sensitivity function with respect to a modeling error between the device model and the second nominal model is approximately 1, the first input value and the second input value being input independently to the vehicle stabilization control unit.

[0241] [6] A control device according to [5], wherein the first auxiliary control unit has a yaw rate control unit that generates a yaw rate command value based on a yaw rate target value, the transfer function of the second nominal model includes a parameter corresponding to the natural vibration frequency of the yaw rate, the yaw rate control unit has a yaw rate phase adjustment unit that adjusts the phase of the yaw rate target value, and the transfer function of the yaw rate phase adjustment unit includes a transfer function capable of converting the parameter in the transfer function of the second nominal model that is corresponding to the natural vibration frequency of the yaw rate into a different value.

[0242] [7] A control device according to [5], wherein the transfer function of the second nominal model includes a parameter corresponding to the natural vibration frequency of the yaw rate, and the second model tracking control unit adjusts the natural vibration frequency of the yaw rate in the transfer function of the device model by adjusting the parameter corresponding to the natural vibration frequency of the yaw rate in the transfer function of the second nominal model.

[0243] [8] A control device according to any one of [1] to [5], wherein the first auxiliary control unit comprises: a vehicle state calculation unit, which calculates a target value of the yaw rate of the vehicle, i.e., a yaw rate target value, and a lateral offset of the vehicle based on input from a camera device; a yaw rate control unit, which generates a yaw rate command value based on the yaw rate target value; and a lateral offset control unit, which generates a lateral offset command value based on the lateral offset, the yaw rate control unit comprising a yaw rate adjustment unit for adjusting the yaw rate command value based on a frequency, the lateral offset control unit comprising a lateral offset adjustment unit for adjusting the lateral offset command value based on a frequency, the gain of the transfer function of the yaw rate adjustment unit in a first frequency band being lower than the gain of the transfer function of the yaw rate adjustment unit in a second frequency band higher than the first frequency band, and the gain of the transfer function of the lateral offset adjustment unit in the second frequency band being lower than the gain of the transfer function of the lateral offset adjustment unit in the first frequency band.

[0244] [9] The control device according to [8], wherein the transfer function of the yaw rate adjustment unit is set to C γ (s), the transfer function of the lateral offset adjustment unit is set to C y (s), let K be a constant that is approximately 1 γy When C γ (s) = K γy -C y (s) established.

[0245]

[10] An electric power steering device comprising: the control device described in any one of [1] to [9]; and the steering mechanism.

[0246]

[11] A control method for controlling a steering mechanism mounted on a vehicle, wherein the control method comprises the following steps: executing lane keeping control to maintain the vehicle within a lane; generating a first input value through the lane keeping control; generating a second input value based on a steering input value input from a steering wheel of the vehicle; calculating a command value based on the first input value multiplied by a first gain and the second input value multiplied by a second gain; and executing the generation of a command value based on an output of a control object including a motor provided in the steering mechanism and a first nominal model based on the structure of the control object. A model tracking control of a correction value for correcting a value; and through the model tracking control, in a frequency band in which the gain in the gain characteristics of the complementary sensitivity function relative to the modeled error between the control object and the first nominal model, i.e., the complementary sensitivity gain, is approximately 1, the transfer function of the control object is constrained to be the transfer function of the first nominal model, the first gain and the second gain are variable values, when the first gain is set to K1 and the second gain is set to K2, K1=1-K2 holds, and the complementary sensitivity function includes a variable parameter that changes according to the second gain.

[0247] The structures and methods described above in this specification can be appropriately combined within a range that does not contradict each other.

Claims

1. A control device for controlling a steering mechanism mounted on a vehicle, wherein: The control device has: a first assist control unit capable of executing lane keeping control for keeping the vehicle in a lane and generating a first input value; a second assist control unit that generates a second input value based on a steering input value input from a steering wheel of the vehicle; as well as a disturbance sensitivity control unit to which is input a command value calculated based on the first input value multiplied by the first gain and the second input value multiplied by the second gain, The first gain and the second gain are variable values, When the first gain is set to K1 and the second gain is set to K2, K1=1-K2 holds. The disturbance sensitivity control unit includes a first model tracking control unit that generates a correction value for correcting the command value based on an output of a control object including a motor provided in the steering mechanism and a first nominal model based on a structure of the control object. The first model tracking control unit is configured to constrain the transfer function of the controlled object to the transfer function of the first nominal model in a frequency band where a gain in a gain characteristic of a complementary sensitivity function with respect to a modeled error between the controlled object and the first nominal model, i.e., a complementary sensitivity gain, is approximately 1; The complementary sensitivity function includes a variable parameter that changes according to the second gain.

2. The control device according to claim 1, wherein: the first gain when the first assist control unit executes the lane keeping control is greater than the first gain when the first assist control unit does not execute the lane keeping control, A steady-state gain of the complementary sensitivity function when the first assist control unit executes the lane keeping control is greater than a steady-state gain of the complementary sensitivity function when the first assist control unit does not execute the lane keeping control.

3. The control device according to claim 1, wherein: The larger the variable parameter, the larger the steady-state gain of the complementary sensitivity function. The variable parameter and the second gain are in a complementary relationship with each other.

4. The control device according to claim 1, wherein: The steering mechanism comprises: An input shaft to which a steering wheel operated by a helmsman is connected; an output shaft connected to the input shaft via a torsion bar; and The motor is connected to the output shaft. The second assist control unit generates an assist torque for compensating for at least a portion of a self-aligning torque generated by a tire of the vehicle, based on an input torque calculated based on a torsion bar torque generated by the torsion bar. calculating the second input value based on the assist torque, The variable parameter is the ratio of the correction value to the disturbance input to the control object. When the spring constant of the torsion bar is set to K tor , the slope of the self-aligning torque generated by the tire of the vehicle with respect to the steering angle as the rotation angle of the output shaft is set to K SAT , the slope of the assist torque relative to the input torque is set to K ass , when the steady-state gain of the complementary sensitivity function is set to T(0) and the variable parameter is set to m, the following equation holds: 。 5. The control device according to claim 1, wherein: The control device includes a vehicle stabilization control unit that constrains a transfer function of a plant model that takes an actual steering angle of a tire of the vehicle as an input and a yaw rate of the vehicle as an output to a transfer function of a second nominal model through model following control. The vehicle stabilization control unit includes a second model following control unit that performs model following control. The second model tracking control unit is configured to constrain the transfer function of the device model to the transfer function of the second nominal model in a frequency band where the gain of the gain characteristic of the complementary sensitivity function with respect to the modeling error between the device model and the second nominal model is substantially 1, The vehicle stabilization control unit receives the first input value and the second input value independently of each other.

6. The control device according to claim 5, wherein: The first assist control unit includes a yaw rate control unit that generates a yaw rate command value based on a yaw rate target value. The transfer function of the second nominal model includes a parameter corresponding to the natural frequency of the yaw rate. The yaw rate control unit includes a yaw rate phase adjustment unit for adjusting the phase of the yaw rate target value. The transfer function of the yaw rate phase adjustment unit includes a transfer function capable of converting a parameter corresponding to the natural frequency of the yaw rate in the transfer function of the second nominal model into a different value.

7. The control device according to claim 5, wherein: The transfer function of the second nominal model includes a parameter corresponding to the natural frequency of the yaw rate. The second model following control unit adjusts the natural frequency of the yaw rate in the transfer function of the plant model by adjusting a parameter corresponding to the natural frequency of the yaw rate in the transfer function of the second nominal model.

8. The control device according to claim 1, wherein: The first auxiliary control unit includes: a vehicle state calculation unit that calculates a target value of the yaw rate of the vehicle, that is, a yaw rate target value, and a lateral deviation of the vehicle based on an input from a camera device; a yaw rate control unit that generates a yaw rate command value based on the yaw rate target value; as well as a lateral offset control unit that generates a lateral offset command value according to the lateral offset, The yaw rate control unit includes a yaw rate adjustment unit for adjusting the yaw rate command value according to a frequency. The lateral offset control unit includes a lateral offset adjustment unit for adjusting the lateral offset command value according to the frequency. a gain of the transfer function of the yaw rate adjustment unit in a first frequency band is lower than a gain of the transfer function of the yaw rate adjustment unit in a second frequency band higher than the first frequency band; A gain of the transfer function of the lateral offset adjustment section in the second frequency band is lower than a gain of the transfer function of the lateral offset adjustment section in the first frequency band.

9. The control device according to claim 8, wherein: When the transfer function of the yaw rate adjustment unit is set to C γ (s), the transfer function of the lateral offset adjustment unit is set to C y (s), let K be a constant that is approximately 1 γy When C γ (s) = K γy -C y (s) established.

10. An electric power steering device, comprising: The control device according to any one of claims 1 to 9; and The steering mechanism.

11. A control method for controlling a steering mechanism mounted on a vehicle, wherein: The control method comprises the following steps: performing lane keeping control to maintain the vehicle within a lane; generating a first input value through the lane keeping control; generating a second input value based on a steering input value input from a steering wheel of the vehicle; calculating a command value based on the first input value multiplied by a first gain and the second input value multiplied by a second gain; executing a model following control for generating a correction value for correcting the command value based on an output of a control object including a motor provided in the steering mechanism and a first nominal model based on a structure of the control object; as well as By the model tracking control, the transfer function of the controlled object is constrained to be the transfer function of the first nominal model in a frequency band where a gain in a gain characteristic of a complementary sensitivity function with respect to a modeled error between the controlled object and the first nominal model, i.e., a complementary sensitivity gain, is approximately 1. The first gain and the second gain are variable values, When the first gain is set to K1 and the second gain is set to K2, K1=1-K2 holds. The complementary sensitivity function includes a variable parameter that changes according to the second gain.

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