Control device, control method, and motor module for an electric power steering device

Abstract

To reduce the calculation load on a calculation circuit while achieving both automatic operation and manual operation functions. A control device for controlling a motor used in an electric power steering device having the motor, in which a processor executes, in accordance with a program, the steps of: performing PI control based on a target steering wheel angle and a steering angle, thereby calculating a target assist torque; and controlling the motor based on the target assist torque. The gain of an integrator for I control of the PI control is variable.

Description

Technical Field

[0001] This disclosure relates to a control device, control method, and motor module for an electric power steering system. This application claims priority based on Japanese Patent Application No. 2020-104210, filed on June 17, 2020, the contents of which are incorporated herein by reference. Background Technology

[0002] Typical automobiles are equipped with an electric motor (hereinafter referred to as "motor") and an electric power steering (EPS) system with a control device for the motor. The electric power steering system is a device that assists the driver in operating the steering wheel (or steering wheel) by driving the motor.

[0003] In recent years, with the development of automatic operation technology, it has become necessary to realize both automatic and manual operation functions in EPS (Electrical Power Supply). When using a single actuator to achieve both automatic and manual operation functions, a technique for switching control methods between the two has been proposed. International Publication No. 2019 / 107437 discloses a technique for switching control between the two by adjusting a weighting coefficient (i.e., ratio) used in the weighted addition between an auxiliary control unit for controlling manual operation and an angle control unit for controlling automatic operation.

[0004] Existing technical documents

[0005] Patent documents

[0006] Patent Document 1: International Publication No. 2019 / 107437 Summary of the Invention

[0007] The problem that the invention aims to solve

[0008] The goal is to further reduce the computational load.

[0009] Embodiments of this disclosure provide a control device and control method for an electric power steering system that can reduce computational load while enabling both automatic and manual operation.

[0010] Methods for solving problems

[0011] In a non-limiting and exemplary embodiment, the control device of this disclosure is used in an electric power steering system having a motor for controlling the motor, wherein the control device has: a processor; and a memory storing a program for controlling the operation of the processor, the processor performing the following steps according to the program: performing PI control based on a target steering wheel angle and a steering angle, thereby calculating a target auxiliary torque; and controlling the motor based on the target auxiliary torque, wherein the gain of the integrator of the I control for the PI control is variable.

[0012] In another non-limiting and illustrative embodiment, the control device of this disclosure is used in an electric power steering system having a motor for controlling the motor, wherein the control device has: a processor; and a memory storing a program for controlling the operation of the processor, the processor performing the following steps according to the program: performing PI control based on a target steering wheel angle and a steering angle, thereby calculating a target auxiliary torque; switching the activation and deactivation of an integrator of I control for the PI control in response to a trigger; and controlling the motor according to the target auxiliary torque.

[0013] In a non-limiting and exemplary embodiment, the motor module of this disclosure has a motor and the control device described above.

[0014] In a non-limiting and exemplary embodiment, the control method of this disclosure is used in an electric power steering system having a motor for controlling the motor, wherein the control method includes the steps of: performing PI control based on a target steering wheel angle and a steering angle, thereby calculating a target auxiliary torque; and controlling the motor based on the target auxiliary torque, wherein the gain of the integrator of the I control for the PI control varies according to the steering wheel torque representing an automatic operation signal.

[0015] Invention Effects

[0016] According to exemplary embodiments of the present disclosure, a new control device and control method for an electric power steering system are provided that can reduce computational load while realizing both automatic and manual operation functions. Attached Figure Description

[0017] Figure 1 This is a schematic diagram illustrating a structural example of an electric power steering device 1000 according to an exemplary embodiment of the present disclosure.

[0018] Figure 2 This is a block diagram illustrating a structural example of a control device 100 according to an exemplary embodiment of the present disclosure.

[0019] Figure 3 This is a functional block diagram illustrating the functional blocks of an EPS controller 230 mounted on a processor 200, representing an exemplary embodiment of the present disclosure.

[0020] Figure 4A This is a functional block diagram illustrating the function blocks of the angle control unit 231 of the EPS controller 230 in the state where the integrator 12c of the first embodiment is activated.

[0021] Figure 4B This is a functional block diagram illustrating other structures of the angle control unit 231 in the state where the integrator 12c of the first embodiment is activated.

[0022] Figure 5 This illustrates the gain or weight of the integrator 12c in the first embodiment in relation to the steering wheel torque T. h A graph showing the relationship between the two.

[0023] Figure 6 This illustrates the effect based on the manual steering wheel angle θ. d With the automatic target steering wheel angle θ r A graph showing the gain that varies with the ratio.

[0024] Figure 7A This is a functional block diagram illustrating the function blocks of the angle control unit 231 of the EPS controller 230 in the manual operation mode of the second embodiment.

[0025] Figure 7B This is a functional block diagram illustrating the function blocks of the angle control unit 231 of the EPS controller 230 in the automatic operation mode of the second embodiment.

[0026] Figure 8A This is a functional block diagram illustrating other structures of the angle control unit 231 of the EPS controller 230 in the manual operation mode of the second embodiment.

[0027] Figure 8B This is a functional block diagram illustrating other structures of the angle control unit 231 of the EPS controller 230 in the automatic operation mode of the second embodiment.

[0028] Figure 9 This illustrates the gain of the integrator 12c in the second embodiment and its relationship with the steering wheel torque T. h A graph showing the relationship between the two. Detailed Implementation

[0029] Before describing the embodiments of this disclosure, the insights discovered by the inventors and the technical background will be explained.

[0030] In the control device disclosed in International Publication No. 2019 / 107437, the auxiliary control unit and the angle control unit are provided as separate control units. The auxiliary control unit sets a target value for the auxiliary torque required for manual operation, and the angle control unit sets a target value for the torque required for angle control. Angle deviation, depending on the driver's input state indicating manual or automatic operation, is input to the shared control unit as input information. The shared control unit calculates a weighting coefficient for weighted addition based on the target values ​​set by the auxiliary control unit and the angle control unit, and outputs the target auxiliary torque. However, according to this method, the functions of both the auxiliary control unit and the angle control unit need to be processed simultaneously, placing a large computational load on the arithmetic circuitry. As a result, there is a problem of requiring expensive arithmetic circuitry with a large data processing capacity.

[0031] According to the research of the inventors, in the control device of an electric power steering system, the gain of the integrator performing the I control in PI control is made variable, or the activation and deactivation of the integrator are switched, depending on the input target steering wheel angle. Thus, it was discovered that the functions of both the auxiliary control unit related to manual operation and the angle control unit related to automatic operation can be realized with a single angle control unit, thereby completing the present invention.

[0032] Hereinafter, with reference to the accompanying drawings, the control device, control method, and embodiments of the electric power steering system of the present disclosure will be described in detail. However, sometimes details beyond what is necessary will be omitted. For example, detailed descriptions of well-known matters and repetitive descriptions of substantially the same structures will be omitted. This is to avoid unnecessarily lengthy descriptions and to facilitate understanding by those skilled in the art.

[0033] The following embodiments are illustrative, and the control device and control method of the electric power steering system disclosed herein are not limited to the following embodiments. For example, the values, steps, and order of the steps shown in the following embodiments are merely examples, and various changes can be made as long as they do not create technical contradictions. The embodiments described below are merely illustrative, and various combinations can be made as long as they do not create technical contradictions.

[0034] 【1. Structure of the Electric Power Steering System 1000】

[0035] Figure 1 This is a schematic diagram illustrating a structural example of the electric power steering device 1000 according to this embodiment.

[0036] The electric power steering system 1000 (hereinafter referred to as "EPS") has a steering system 520 and an auxiliary torque mechanism 540 that generates auxiliary torque. The EPS 1000 generates auxiliary torque that assists the steering torque of the steering system generated by the driver's operation of the steering wheel. The auxiliary torque reduces the driver's workload.

[0037] The steering system 520 includes, for example, a steering wheel 521, a steering shaft 522, universal joints 523A and 523B, a rotary shaft 524, a rack and pinion mechanism 525, a rack shaft 526, left and right ball joints 552A and 552B, a steering tie rod 527A and 527B, a steering knuckle 528A and 5528, and left and right steering wheels 529A and 529B.

[0038] The auxiliary torque mechanism 540 includes, for example, a steering torque sensor 541, a steering angle sensor 542, an automotive electronic control unit (ECU) 100, a motor 543, a reduction gear 544, an inverter 545, and a torsion bar 546. The steering torque sensor 541 detects the steering torque in the steering system 520 by detecting the amount of torsion in the torsion bar 546. The steering angle sensor 542 detects the steering angle of the steering wheel. Alternatively, the steering torque may not be the value from the steering torque sensor, but rather an inferred value derived through calculation. The steering angle can also be calculated based on the output value of an angle sensor.

[0039] The ECU 100 generates a motor drive signal based on detection signals from the steering torque sensor 541, steering angle sensor 542, and vehicle speed sensor (not shown), and outputs it to the inverter 545. For example, the inverter 545 converts DC power into three-phase AC power as pseudo-sine waves (A-phase, B-phase, and C-phase) based on the motor drive signal and supplies it to the motor 543. The motor 543, for example, is a surface magnet synchronous motor (SPMSM) or a switched reluctance motor (SRM), and generates an auxiliary torque corresponding to the steering torque upon receiving the three-phase AC power supply. The motor 543 transmits the generated auxiliary torque to the steering system 520 via a reduction gear 544. Hereinafter, the ECU 100 will be referred to as the EPS control device 100.

[0040] The control unit 100 and the motor are modularized and manufactured and sold as a motor module. The motor module, having both a motor and the control unit 100, is suitable for use with EPS. Alternatively, the control unit 100 can be manufactured and sold independently of the motor as a control device for controlling EPS.

[0041] 【2. Example of the structure of control device 100】

[0042] Figure 2This is a block diagram illustrating a typical example of the structure of the control device 100 of this embodiment. 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 circuit board (PCB) on which these electronic components are mounted.

[0043] The vehicle speed sensor 300, steering torque sensor 541, and steering angle sensor 542 mounted on the vehicle are electrically connected to the processor 200, and send vehicle speed v, steering torque Ts, and steering angle θ to the processor 200 from the vehicle speed sensor 300, steering torque sensor 541, and steering angle sensor 542, respectively.

[0044] Control device 100 and inverter 545 (see reference) Figure 1 Electrical connection. The control device 100 controls the switching operation of multiple switching elements (e.g., MOSFETs) in the inverter 545. Specifically, the control device 100 generates control signals (hereinafter referred to as "gate control signals") to control the switching operation of each switching element and outputs them to the inverter 545.

[0045] The control device 100 generates torque command values ​​based on vehicle speed v, steering torque Ts, etc., and controls the torque and rotational speed of motor 543, for example, through vector control. The control device 100 is not limited to vector control and can also perform other closed-loop controls. The rotational speed is expressed as the rotor speed (rpm) per unit time (e.g., 1 minute) or the rotor speed (rps) per unit time (e.g., 1 second). Vector control is a method that decomposes the current flowing in the motor into current components that contribute to torque generation and current components that contribute to magnetic flux generation, and independently controls these mutually orthogonal current components.

[0046] The power supply circuit 111 is connected to an external power source (not shown) to generate the DC voltage required by each block within the circuit. The generated DC voltage is, for example, 3V or 5V.

[0047] Angle sensor 112 is, for example, a rotary transformer or a Hall effect IC. Alternatively, angle sensor 112 can also be implemented by a combination of an MR sensor with a magnetoresistive (MR) element and a sensor magnet. Angle sensor 112 detects the rotation angle of the rotor and outputs it to processor 200. Control device 100 may replace angle sensor 112 with speed sensor or acceleration sensor that detects the rotational speed and acceleration of the motor.

[0048] Input circuit 113 receives the motor current value (hereinafter referred to as "actual current value") detected by a current sensor (not shown), converts the level of the actual current value to the input level of processor 200 as needed, and outputs the actual current value to processor 200. A typical example of input circuit 113 is an analog-to-digital converter circuit.

[0049] Processor 200 is a semiconductor integrated circuit, also known as a central processing unit (CPU) or microprocessor. Processor 200 sequentially executes a computer program stored in ROM 116, which describes a set of instructions for controlling the motor drive, to achieve the desired processing. Processor 200 is widely interpreted as including FPGA (Field Programmable Gate Array), ASIC (Application Specific Integrated Circuit), or ASSP (Application Specific Standard Product) devices equipped with a CPU. Processor 200 sets a target current value based on the actual current value and the rotor's rotation angle, generates a PWM signal, and outputs it to the drive circuit 115.

[0050] The communication I / F 114 is, for example, an input / output interface used for transmitting and receiving data based on the vehicle's control area network (CAN).

[0051] The drive circuit 115 is typically a gate driver (or pre-driver). The drive circuit 115 generates gate control signals based on the PWM signal, providing these signals to the gates of the multiple switching elements in the inverter 545. When the driven object is a motor that can be driven at low voltage, a gate driver may not always be necessary. In this case, the gate driver function can be implemented in the processor 200.

[0052] ROM 116 is electrically connected to processor 200. ROM 116 is, for example, a writable memory (e.g., PROM), a rewritable memory (e.g., flash memory, EEPROM), or a read-only memory. ROM 116 stores a control program containing a set of instructions for enabling processor 200 to control motor drive. For example, the control program is temporarily expanded in RAM (not shown) during boot.

[0053] Figure 3This is a functional block diagram illustrating the EPS controller 230 of an exemplary embodiment of the present disclosure, mounted on the processor 200. The processor 200 in the exemplary embodiment of the present disclosure can be implemented by the EPS controller 230, which has an angle control unit 231, a current control unit 232, and a PWM (Pulse Width Modulation) modulation unit 233 as functional blocks. Typically, the processing (or tasks) of the functional blocks corresponding to each unit are described in a computer program as software modules and stored in ROM 116. However, when using an FPGA or the like, all or part of these functional blocks can be mounted as hardware accelerators.

[0054] When each functional block is installed as software (or firmware) in the control device 100, the execution entity of the software may be the processor 200. In one embodiment, the control device of this disclosure has a processor 200 and a memory storing a program that controls the operation of the processor 200. The processor 200 executes the following steps according to the program: (1) based on the target steering wheel angle and steering angle θ g To perform PI control, the target auxiliary torque T is calculated. r ; and (2), based on the target auxiliary torque T r To control the motor. Based on the target auxiliary torque T r Controlling the motor includes the following: based on the target auxiliary torque T r The current is controlled to calculate the command voltage Vr; and the command voltage Vr is modulated using PWM to generate a PWM signal. Here, the gain of the integrator used for PI control is variable.

[0055] In another manner, the processor 200 performs the following steps according to the program: (1) based on the target steering wheel angle and steering angle θ g To perform PI control, the target auxiliary torque T is calculated. r (2) In response to a trigger, the integrator of the I-control for PI control is switched on and off; and (3) Based on the target auxiliary torque T r This is used to control the motor. Examples of triggers include hand-on / hand-off commands indicating a hands-on or hands-off state, signals that vary based on the relationship between the steering wheel torque or torsional torque (indicating automatic operation) and a threshold value, or mode commands output from a higher-level device. An example of a higher-level device is a higher-level ECU (Electronic Control Unit). Details about triggers will be explained later.

[0056] In another embodiment, where the functional blocks are installed as software and / or hardware in the control device 100, the control device 100 of this disclosure includes an angle control unit that adjusts the target steering wheel angle and steering angle θ. g To perform PI control, the target auxiliary torque T is calculated. r The current control unit, based on the target auxiliary torque T... r The system performs current control, thereby calculating the command voltage Vr; and a PWM modulation unit, which modulates the command voltage Vr to generate a PWM signal. Here, the gain of the integrator for PI control is variable. Furthermore, in another embodiment, the control device 100 includes an angle control unit that can adjust the target steering wheel angle and steering angle θ based on the target steering wheel angle and steering angle θ. g To perform PI control, the target auxiliary torque T is calculated. r The integrator for PI control is activated and deactivated in response to a trigger; the current control unit, based on the target auxiliary torque T... r The current control is performed to calculate the command voltage Vr; and the PWM modulation unit modulates the command voltage Vr to generate a PWM signal.

[0057] EPS controller 230 calculates the target steering wheel angle and steering angle θ. g To perform PI control, the target auxiliary torque T is calculated. r The target steering wheel angle in embodiments of this disclosure may include the manual steering wheel angle θ. d and automatic target steering wheel angle θ r In this manual, the manual steering wheel angle θ is sometimes referred to as... d Or automatically target steering wheel angle θ r It is described as the target steering wheel angle.

[0058] The EPS control device 200 in the embodiments of this disclosure can be considered as an angle controller. The EPS controller 230 in the embodiments of this disclosure includes an angle control unit 231, a current control unit 232, and a PWM modulation unit 233. The automatic target steering wheel angle θ is controlled by... r Manual steering wheel angle θ d and steering angle θ g The input signal is given to the EPS controller 230. The EPS controller 230 performs input with the automatic target steering wheel angle θ. r Manual steering wheel angle θ d The control switches between manual and automatic operation modes by switching the angle-related command values ​​and adjusting the integral term.

[0059] Angle control unit 231 determines the automatic target steering wheel angle θ based on the angle of the steering wheel.r Or manually adjust the steering wheel angle θ d and steering angle θ g To calculate the target auxiliary torque T r And output. Manual steering wheel angle θ d This indicates the angle of the steering wheel moved by the driver in manual mode. Automatic target steering wheel angle θ r This represents the target value of the steering wheel angle derived from sensors such as cameras in automatic operation mode. In embodiments of this disclosure, based on the target steering wheel angle, the gain of the integrator in PI control is changed, or the integrator is switched between being active and inactive.

[0060] In manual operation mode, the angle control unit 231 adjusts the steering angle θ. g Follow the manual steering wheel angle θ d While power-assisted control is being implemented, residual deviations in this power-assisted control become steering torque. Meanwhile, in automatic operation mode, the angle control unit 231 adjusts the steering angle θ. g Follows the automatic target steering wheel angle θ r This eliminates residual deviations. Thus, the functions of both the auxiliary control involved in manual operation and the angle control involved in automatic operation are integrated into a single angle control unit. The difference between manual and automatic operation modes lies in the difference in angle-related command values, and specifically, the presence or absence of an integrator for I-control (described later).

[0061] In embodiments of this disclosure, the EPS controller 230 generally has a manual operation mode and an automatic operation mode, but can further divide the above two modes into four control modes based on a combination of the target steering wheel angle input to the angle control unit 231 and the effective, ineffective, or variable gain of the I control. The four control modes are listed below. In the second to fourth control modes described below, by changing the gain in the I control according to the target steering wheel angle, the steering feel perceived by the driver can be appropriately adjusted.

[0062]

Control Mode 1

[0063] The first control mode causes the processor to execute actions based on the manual steering wheel angle θ. d The P control mode corresponds to the manual operation mode. The driver can feel the residual deviation of the steering angle relative to the manual steering wheel angle during steering, which serves as the steering feel.

[0064] [Second Control Mode]

[0065] The second control mode enables the processor to execute actions based on the manual steering wheel angle θ. dIt uses PI control mode. This mode corresponds to manual operation mode, but torque is assisted by additional I control. Therefore, the driver is less likely to experience fatigue.

[0066] [Third Control Mode]

[0067] The third control mode enables the processor to execute actions based on the manual steering wheel angle θ. d and automatic target steering wheel angle θ r The PI control mode corresponds to the semi-automatic operation mode. The driver has further feedback on the steering wheel angle.

[0068] [4th Control Mode]

[0069] The fourth control mode enables the processor to execute actions based on the automatic target steering wheel angle θ. r The PI control mode corresponds to a fully automatic operation mode. The driver can keep the vehicle moving even when the hands are off the wheel.

[0070] Reference Figures 4A to 6 This section provides a detailed description of the functions and operations of the angle control unit 231 in the EPS controller 230.

[0071] (First Embodiment)

[0072] According to the EPS controller 230 in this embodiment, the gain of the integrator used in the I-control of PI control is variable, triggered by certain signals or commands. The integrator used for I-control in PI control is optimized.

[0073] Figure 4A This is a functional block diagram illustrating the function block of the angle control unit 231 of the EPS controller 230 when the integrator 12c is activated. Figure 4B This is a functional block diagram illustrating other structures of the angle control unit 231 in the state where the integrator 12c is activated. Figure 5 This illustrates the relationship between the gain or weight of integrator 12c and steering wheel torque T. h A graph showing the relationship between the two.

[0074] like Figure 4A As illustrated, the angle control unit 231 includes a subtractor 10, a torsion bar stiffening unit 11, a P controller 12a, a D controller 12b, an I controller 12c, and an adder 13. In this specification, the I controller is sometimes referred to as an integrator, and the D controller as a differentiator. The angle control unit 231 determines the target steering wheel angle and the steering angle θ. g To perform PI control, the target auxiliary torque T is calculated. r .

[0075] exist Figure 5 In the example of the curve shown, the steering wheel torque T h The state where the hand is released is either nonexistent or, even if present, very minor. This state corresponds to the automatic operation mode. The EPS controller 230 operates according to the fourth control mode. Here, the steering wheel torque T... h This indicates an automatic operation signal. In control mode 4, the gain of integrator 12c is at its maximum, and this gain is independent of the steering wheel torque T. h And represents a constant value.

[0076] Steering wheel torque T h The system is always in manual operation mode. The EPS controller 230 operates according to the second control mode. In the second control mode, the gain of the integrator 12c is not exactly zero, but represents a small value. However, this value is constant.

[0077] Steering wheel torque T in the specified 2nd and 4th control modes h The area between automatic and manual operation is the hand-held state. The EPS controller 230 operates according to the third control mode. In the third control mode, with the steering wheel torque T... h As the gain increases, the gain of integrator 12c decreases continuously. However, this is not limited to this example; for instance, the gain of integrator 12c can decrease in stages or change continuously without linearity.

[0078] like Figure 4A As illustrated, integrator 12c is activated regardless of the control mode. The manual steering wheel angle θ is... d and automatic target steering wheel angle θ r At least one of the values ​​is input to the angle control unit 231 as the target steering wheel angle. In the second and third control modes, the value output from the subtractor 10 includes the manual steering wheel angle θ. d and automatic target steering wheel angle θ r The target steering wheel angle and steering angle θ are included. g The deviations are input to P controller 12a, D controller 12b, and I controller 12c, respectively. In the fourth control mode, the automatic target steering wheel angle θ output from subtractor 10... r With steering angle θ g The deviations are input to P controller 12a, D controller 12b, and I controller 12c, respectively. Adder 13 adds the output values ​​from P controller 12a, D controller 12b, and I controller 12c to output the target auxiliary torque T. r However, as Figure 4BAs shown, the D controller 12b is not a necessary component; the angle control unit 231 only needs to have at least the P controller 12a and the I controller 12c. By utilizing the D controller 12b, the responsiveness to instantaneous disturbances can be improved.

[0079] Steering wheel torque T h It can be used to determine whether a hand is gripping or releasing its grip. Figure 5 In the example, the gain of integrator 12c, when the third control mode is selected, is based on the steering wheel torque T. h The value changes continuously. By keeping the integrator 12c always active, any residual deviation that may remain can be reduced to zero by P control alone. This eliminates the angular error between the target steering wheel angle and the actual steering angle, resulting in the ability to travel along the target trajectory. As a variation, the steering wheel torque T can be replaced... h And using torsional torque T tor The value of .

[0080] Figure 6 This illustrates the effect based on the manual steering wheel angle θ. d With the automatic target steering wheel angle θ r The gain curve varies with the ratio. In one mode, the gain of integrator 12c can be adjusted according to the manual steering wheel angle θ. d With the automatic target steering wheel angle θ r The slope of the line changes according to the ratio. This ratio, i.e., the slope of the line, can be determined based on the mode command output from the host device. Figure 6 In the example, the ratio changes linearly, but it is not limited to this; it can change non-linearly or in stages.

[0081] Refer again Figure 3 .

[0082] For example, the target auxiliary torque T r Motor angle θ m and the actual current value I m The signal is input to the current control unit 232 as an input signal. The current control unit 232, for example, uses vector control based on the target auxiliary torque T. r Motor angle θ m and the actual current value I m Current control is performed to calculate the command voltage Vr. The PWM modulation unit 233 modulates the command voltage Vr to generate a PWM signal and outputs it to the drive circuit 115.

[0083] According to this embodiment, manual and automatic operation modes are controlled using a single angle controller, thus reducing the amount of data that processing circuits such as processors must process compared to existing technologies. As a result, the cost of the processing circuits can be reduced.

[0084] (Second Implementation)

[0085] Reference Figures 7A to 9 The EPS controller 230 in the second embodiment will be described below. Hereinafter, the differences from the EPS controller 230 in the first embodiment will be mainly described.

[0086] Figure 7A This is a functional block diagram illustrating the function block of the angle control unit 231 of the EPS controller 230 in manual operation mode. Figure 7B This is a functional block diagram illustrating the function block of the angle control unit 231 of the EPS controller 230 in automatic operation mode. Figure 8A This is a functional block diagram illustrating other structures of the angle control unit 231 of the EPS controller 230 in manual operation mode. Figure 8B This is a functional block diagram illustrating other structures of the angle control unit 231 of the EPS controller 230 in automatic operation mode. Figure 9 This example illustrates the relationship between the gain of integrator 12c and steering wheel torque T. h A graph showing the relationship between the two.

[0087] In this embodiment, the EPS controller 230 is triggered by certain signals or instructions to switch the activation and deactivation of the integrator 12c used for PI control. For example... Figure 9 As illustrated, the control modes in this embodiment include a first control mode and a fourth control mode. The steering wheel torque T... h In a state where the element is absent or present but minimal (i.e., when the hand is released), the EPS controller 230 operates according to control mode 4. The integrator 12c is activated, and its gain is fixed to a constant value. For example... Figure 7B As shown, the angle control unit 231 determines the automatic target steering wheel angle θ based on the angle of the steering wheel. r and steering angle θ g To calculate the target auxiliary torque T r However, as Figure 8B As shown, differentiator 12b is not required.

[0088] Steering wheel torque T h In the always-occurring state, i.e., the hand-held state, the EPS controller 230 operates according to the first control mode. The integrator 12c is completely disabled, resulting in a gain of zero. For example... Figure 7AAs shown, the angle control unit 231 adjusts the manual steering wheel angle θ according to the angle of the manual steering wheel. d and steering angle θ g To calculate the target auxiliary torque T r However, as Figure 8A As shown, differentiator 12b is not required.

[0089] Examples of triggers include hand grip / release commands indicating a gripping or releasing state, mode commands output from a higher-level device, or steering wheel torque T indicating an automatic operation signal. h With threshold V th The signal changes according to the magnitude of the torque. However, it can replace the steering wheel torque T. h And using torsional torque T tor The value of . For example Figure 9 As shown, at the steering wheel torque T h Less than threshold V th Within the specified range, the EPS controller 230 operates according to the fourth control mode, with the steering wheel torque T... h Threshold V th Within the above range, the EPS controller 230 operates according to the first control mode.

[0090] In this embodiment, the angle control unit 231 responds to a hand grip / hand release command indicating a hand gripping state or a hand release state, or a mode command output from a host device, to select the manual steering wheel angle θ. d and automatic target steering wheel angle θ r One of the input values ​​is used as the input value for PI control. The angle control unit 231 switches the integrator 12c between active and inactive states based on the selected input value. More specifically, the angle control unit 231 responds to a hand grip / hand release command indicating the hand-release state and selects the automatic target steering wheel angle θ. r As the input value for PI control, the integrator 12c is activated. Conversely, the angle control unit 231 responds to a hand grip / hand release command indicating the hand grip state and selects the manual steering wheel angle θ. d As an input value used for PI control, it disables integrator 12c.

[0091] According to this embodiment, similar to the first embodiment, manual / automatic operation mode control is achieved using a single angle controller. Therefore, compared to the prior art, the amount of data that the processing circuitry such as the processor needs to process can be reduced. As a result, the cost of the processing circuitry can be suppressed.

[0092] Industrial availability

[0093] The embodiments of this disclosure can be used in control devices for controlling EPS mounted in vehicles.

[0094] Label Explanation

[0095] 100: Control device; 111: Power supply circuit; 112: Angle sensor; 113: Input circuit; 114: Communication I / F; 115: Drive circuit; 116: ROM; 200: Processor; 230: EPS controller; 231: Angle control unit; 232: Current control unit; 233: PWM modulation unit.

Claims

1. A control device used in an electric power steering system having a motor, for controlling said motor, wherein, The control device has: Processor; and The memory stores programs that control the operation of the processor. The processor performs the following steps according to the program: PI control is performed based on the target steering wheel angle and steering angle to calculate the target auxiliary torque; and The motor is controlled according to the target auxiliary torque. The gain of the I-controlled integrator used for the PI control is variable, depending on the input target steering wheel angle. The target steering wheel angle includes the manual steering wheel angle and the automatic target steering wheel angle. The gain varies according to the ratio of the manual steering wheel angle to the automatic target steering wheel angle. The ratio is determined based on the mode command output from the host device.

2. A control device used in an electric power steering system having a motor, for controlling the motor, wherein, The control device has: Processor; and The memory stores programs that control the operation of the processor. The processor performs the following steps according to the program: PI control is performed based on the target steering wheel angle and steering angle to calculate the target auxiliary torque. Based on the input target steering wheel angle, the integrator of the I-control used for the PI control is activated and deactivated in response to a trigger; and The motor is controlled according to the target auxiliary torque. The target steering wheel angle includes the manual steering wheel angle and the automatic target steering wheel angle. The gain of the integrator varies according to the ratio of the manual steering wheel angle to the automatic target steering wheel angle. The ratio is determined based on the mode command output from the host device.

3. The control device according to claim 2, wherein, The trigger is a command indicating whether the hand is in a gripping or releasing state.

4. The control device according to claim 2, wherein, The trigger is a signal that varies based on the relationship between the steering wheel torque or torsional torque, which represents an automatic operation signal, and a threshold value.

5. The control device according to claim 2, wherein, The trigger is a mode command output from the host device.

6. The control device according to claim 2, wherein, The processor responds to a hand grip / release command indicating a hand gripping or releasing state, or a mode command output from a host device, and selects either the manual steering wheel angle or the automatic target steering wheel angle as the input value for the PI control. The processor switches between validating and invalidating the integrator based on the selected input value.

7. The control device according to any one of claims 1 to 6, wherein, The PI control also includes D control.

8. A motor module comprising: Motor; and The control device according to any one of claims 1 to 7.

9. A control method used in an electric power steering system having a motor, for controlling the motor, wherein, The control method includes the following steps: PI control is performed based on the target steering wheel angle and steering angle to calculate the target auxiliary torque; and The motor is controlled according to the target auxiliary torque. The gain of the integrator used for the PI control varies according to the steering wheel torque or torsional torque representing the automatic operation signal. The target steering wheel angle includes the manual steering wheel angle and the automatic target steering wheel angle. The gain varies according to the ratio of the manual steering wheel angle to the automatic target steering wheel angle. The ratio is determined based on the mode command output from the host device. This further reduces the computational load.

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