Apparatus and method for controlling motor-driven power steering system

Abstract

Disclosed herein are an apparatus and method for controlling a motor-driven power steering system. The apparatus for controlling a motor-driven power steering system includes: an input / output interface connected to a motor angle sensor, a steering angle sensor, and a position controller; and a processor connected to the input / output interface; wherein, when the motor angle sensor fails, the processor calculates a sum value of a result value obtained by applying a first weight value to the motor angle of the drive motor output from the motor angle sensor and a result value obtained by applying a second weight value to the steering angle of the steering wheel output from the steering angle sensor, and feeding back the sum value to the position controller. The present disclosure can perform stable steering control of a vehicle even when a motor angle sensor malfunctions.

Description

Technical Field

[0001] Exemplary embodiments of the present disclosure relate to an apparatus and method for controlling a motor-driven power steering system, and more particularly, to an apparatus and method for controlling a motor-driven power steering system capable of performing stable steering control of a vehicle even when a motor angle sensor fails. Background Art

[0002] A motor-driven power steering system includes a position controller, a speed controller, a current controller, and a driving motor, each of which calculates a command value based on an error between a sensed value measured by a sensor and a command value, and controls the motor according to the calculated command value.

[0003] Figure 1 : is an example diagram showing a power steering system driven by an R-type motor. Figure 1 As shown, a motor-driven power steering system generally performs position control on a drive motor based on a motor angle of the drive motor detected by a motor angle sensor, and when the motor angle sensor fails, it is necessary to replace the motor angle sensor with another device or method.

[0004] Recently, a technology is being developed to replace the motor angle sensor with a steering angle sensor when the motor angle sensor fails. However, the existing method has a problem in that vibration occurs or steering control becomes unstable during the process of replacing the motor angle sensor with the steering angle sensor.

[0005] The related art of the present disclosure is disclosed in Korean Patent Publication Application No. 10-2022-014460 (published on October 27, 2022). Summary of the invention

[0006] Various embodiments are directed to an apparatus and method for controlling a motor-driven power steering system that stably switches from motor angle-based steering control to steering angle-based steering control when a motor angle sensor fails.

[0007] In one embodiment, a device for controlling a motor-driven power steering system may include: an input / output interface connected to a motor angle sensor, a steering angle sensor, and a position controller; and a processor connected to the input / output interface; wherein, when the motor angle sensor fails, the processor calculates the sum of a result value obtained by applying a first weight value to the motor angle of a drive motor output from the motor angle sensor and a result value obtained by applying a second weight value to the steering angle of a steering wheel output from the steering angle sensor, and feeds the sum value back to the position controller.

[0008] In the present disclosure, the input / output interface can be connected to the speed controller, and when the motor angle sensor fails, the processor can calculate the sum of a result value obtained by applying a first weight value to the motor angle speed of the drive motor output from the motor angle sensor and a result value obtained by applying a second weight value to the steering angle speed of the steering wheel output from the steering angle sensor, and feed the sum value back to the speed controller.

[0009] In the present disclosure, an initial value of the first weight value may be 0, and the processor may gradually reduce the first weight value until the first weight value becomes 0.

[0010] In the present disclosure, an initial value of the second weight value may be 0, and the processor may gradually increase the second weight value until the second weight value becomes 1.

[0011] In the present disclosure, the processor may set the first weight value and the second weight value so that the sum of the first weight value and the second weight value may be 1.

[0012] In the present disclosure, the processor may set the amount of change per unit time of the first weight value and the second weight value based on the steering angular velocity of the steering wheel.

[0013] In the present disclosure, the processor may set the amount of change per unit time to increase as the steering angular velocity of the steering wheel increases.

[0014] In the present disclosure, when the motor angle sensor does not fail, the motor angle of the drive motor output from the motor angle sensor may be fed back to the position controller, and the motor angle speed of the drive motor output from the motor angle sensor may be fed back to the speed controller.

[0015] In one embodiment, a method for controlling a motor-driven power steering system may include: when a motor angle sensor fails, calculating a first result value by applying a first weight value to a motor angle of a drive motor output from the motor angle sensor; calculating a second result value by applying a second weight value to a steering angle of a steering wheel output from a steering angle sensor; and calculating a sum of the first result value and the second result value, and feeding the sum value back to a position controller. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 is an exemplary diagram illustrating a motor-driven power steering system.

[0017] Figure 2 is a block diagram illustrating an apparatus for controlling a motor-driven power steering system according to one embodiment of the present disclosure.

[0018] Figure 3is a block diagram illustrating a processor according to one embodiment of the present disclosure.

[0019] Figure 4 is an exemplary diagram showing relationship information about a setting time according to a steering angular velocity.

[0020] Figure 5 is a flow chart illustrating a method for controlling a motor-driven power steering system according to one embodiment of the present disclosure. DETAILED DESCRIPTION

[0021] The components described in the example embodiments may be implemented by hardware components, for example, the hardware components include at least one digital signal processor (DSP), a processor, a controller, an application-specific integrated circuit (ASIC), a programmable logic element (such as a field programmable gate array (FPGA)), other electronic devices, or a combination thereof. The functions or processes described in at least some of the example embodiments may be implemented by software, and the software may be recorded on a recording medium. The components, functions, and processes described in the example embodiments may be implemented by a combination of hardware and software.

[0022] The method according to the example embodiments may be embodied as a program executable by a computer and may be implemented as various recording media (eg, a magnetic storage medium, an optical reading medium, and a digital storage medium).

[0023] The various techniques described herein may be implemented as digital electronic circuits, or computer hardware, firmware, software, or a combination thereof. The various techniques may be implemented as a computer program product, i.e., a computer program tangibly embodied in an information carrier, for example, the computer program tangibly embodied in a machine-readable storage device (e.g., a computer-readable medium) or embodied in a propagation signal, so as to be processed by the operation of a data processing device (e.g., a programmable processor, a computer, or multiple computers) or to control the operation of a data processing device. The computer program may be written in any form of programming language (including compiled or interpreted languages) and may be deployed in any form including stand-alone programs or modules, components, subroutines, or other units suitable for use in a computing environment. The computer program may be deployed to execute on one or more computers at one site or distributed across multiple sites, or interconnected via a communication network.

[0024] For example, processors suitable for executing computer programs include general and special purpose microprocessors, and any one or more processors of any type of digital computer. Typically, the processor will receive instructions and data from a read-only memory or a random access memory or both. The elements of a computer may include at least one processor for executing instructions and one or more memory devices for storing instructions and data. In general, a computer also includes or is coupled to receive data from one or more mass storage devices, transfer data to one or more mass storage devices, or perform both on one or more mass storage devices, which mass storage devices (e.g., magnetic disks, magneto-optical disks, or optical disks) are used to store data. Examples of information carriers suitable for implementing computer program instructions and data include semiconductor storage devices, such as magnetic media such as hard disks, floppy disks and magnetic tapes, optical media such as compact disk read only memory (CD-ROM), digital video disks (DVD), etc., magneto-optical media such as floppy disks, read only memory (ROM), random access memory (RAM), flash memory, erasable programmable ROM (EPROM) and electrically erasable programmable ROM (EEPROM), and any other known computer readable medium. The processor and memory may be supplemented by or integrated into special purpose logic circuitry.

[0025] The processor can run an operating system (OS), and one or more software applications run on the operating system. The processor device can also access, store, operate, process and create data in response to the execution of the software. For simplicity, the description of the processor device is used as a singular; however, those skilled in the art will understand that the processor device may include multiple processing elements and / or multiple types of processing elements. For example, the processor device may include multiple processors, or a processor and a controller. In addition, different processing configurations are also possible, such as parallel processors.

[0026] Furthermore, non-transitory computer readable media can be any available media that can be accessed by a computer and may include computer storage media and transmission media.

[0027] This specification includes details of many specific embodiments, but it should be understood that these details do not limit any invention or limit the content that can be claimed in the specification, but rather describe the features of specific example embodiments. The features described in the specification in the context of each example embodiment can be implemented as a combination in a single example embodiment. On the contrary, the various features described in the specification in the context of a single example embodiment can be implemented in multiple example embodiments individually or in appropriate sub-combinations. In addition, the features can operate in a specific combination and can be initially described in the combination as required, but in some cases, one or more features can be excluded from the required combination, and the required combination can be changed to a sub-combination or a modification of the sub-combination.

[0028] Similarly, even if operations are described in a particular order on the accompanying drawings, it should not be understood that the operations need to be performed in a particular order or sequence to obtain the desired results, or that all operations need to be performed. In certain circumstances, multitasking and parallel processing may be advantageous. In addition, it should not be understood that the various device components in the above-described example embodiments need to be separated in all example embodiments, and it should be understood that the above-described program components and devices can be incorporated into a single software product or can be packaged in multiple software products.

[0029] It should be understood that the example embodiments disclosed herein are only illustrative and are not intended to limit the scope of the present invention. It is obvious to those skilled in the art that various modifications may be made to the example embodiments without departing from the spirit and scope of the technical solutions of the present disclosure and their equivalents.

[0030] Hereinafter, with reference to the accompanying drawings, embodiments of the present disclosure will be described in detail so that those skilled in the art can easily perform the present disclosure. However, the present disclosure can be embodied in many different forms and is not limited to the embodiments described herein.

[0031] In the following description of the embodiments of the present disclosure, when it may make the subject matter of the present disclosure rather unclear, a detailed description of known functions and configurations contained herein will be omitted. Parts of the drawings that are not related to the description of the present disclosure are omitted, and similar parts are represented by similar reference numerals.

[0032] In the present disclosure, components that are distinguished from each other are intended to clearly illustrate each feature. However, this does not necessarily mean that these components are separate. That is, multiple components can be integrated into one hardware or software unit, or a single component can be distributed to multiple hardware or software units. Therefore, unless otherwise specified, such integrated or distributed implementations are also included in the scope of the present disclosure.

[0033] In the present disclosure, the components described in various embodiments are not necessarily necessary components, and some components may be optional components. Therefore, an embodiment consisting of a subset of the components described in one embodiment is also included in the scope of the present disclosure. In addition, in addition to the components described in each embodiment, an embodiment including other components is also included in the scope of the present disclosure.

[0034] Hereinafter, with reference to the accompanying drawings, embodiments of the present disclosure will be described in detail so that those skilled in the art can easily perform the present disclosure. However, the present disclosure can be embodied in many different forms and is not limited to the embodiments described herein.

[0035] In the following description of the embodiments of the present disclosure, when it may make the subject matter of the present disclosure rather unclear, a detailed description of known functions and configurations contained herein will be omitted. Parts of the drawings that are not related to the description of the present disclosure are omitted, and similar parts are represented by similar reference numerals.

[0036] In the present disclosure, when a component is referred to as being "linked," "coupled," or "connected" to another component, it should be understood that not only a direct connection relationship but also an indirect connection relationship through an intermediate component may be included. In addition, when a component is referred to as "including" or "having" another component, it may mean further including the other component rather than excluding it, unless there is a clear description to the contrary.

[0037] In the present disclosure, the terms "first", "second", etc. are only used to distinguish one component from another component, and do not limit the order or importance of the components, etc., unless otherwise specifically stated. Therefore, within the scope of the present disclosure, a first component in one exemplary embodiment may be referred to as a second component in another embodiment, and similarly, a second component in one exemplary embodiment may be referred to as a first component.

[0038] In the present disclosure, components that are distinguished from each other are intended to clearly illustrate each feature. However, this does not necessarily mean that these components are separate. That is, multiple components can be integrated into one hardware or software unit, or a single component can be distributed to multiple hardware or software units. Therefore, unless otherwise specified, such integrated or distributed implementations are also included in the scope of the present disclosure.

[0039] In the present disclosure, the components described in various embodiments are not necessarily necessary components, and some components may be optional components. Therefore, an embodiment consisting of a subset of the components described in one embodiment is also included in the scope of the present disclosure. In addition, in addition to the components described in each embodiment, an embodiment including other components is also included in the scope of the present disclosure.

[0040] Hereinafter, an apparatus and method for controlling a motor-driven power steering system according to an embodiment of the present disclosure will be described in detail with reference to the accompanying drawings. In the following description, the thickness of the lines and the sizes of the components shown in the accompanying drawings are exaggerated for clarity and convenience of explanation. In addition, the terms described below are defined in consideration of the functions of the present disclosure, and these terms may vary according to the intention or habits of the user or operator. Therefore, the definitions of the terms used herein should follow the context disclosed herein.

[0041] Figure 2 is a block diagram showing an apparatus for controlling a motor-driven power steering system according to one embodiment of the present disclosure, Figure 4 : is a diagram showing an example of relationship information of the setting time according to the steering angular velocity.

[0042] refer to Figure 2 According to one embodiment of the present disclosure, the apparatus 100 for controlling a motor-driven power steering system may include an input / output interface 110, a memory 120, and a processor 130. The components included in the apparatus 100 for controlling a motor-driven power steering system may be connected via a common bus. Each component may be connected via a separate interface or a separate bus instead of a common bus based on the processor 130. In addition to the apparatus 100 for controlling a motor-driven power steering system according to one embodiment of the present disclosure, Figure 2 Various components may be included in addition to the components shown, or some components may be omitted. The apparatus 100 for controlling a motor-driven power steering system according to one embodiment of the present disclosure may be applied to an autonomous driving vehicle, but the present disclosure is not limited thereto.

[0043] The input / output interface 110 may receive data from an external component and output the received data to the processor 130, which will be described below. According to one embodiment, the input / output interface 110 may be connected to a motor angle sensor 20 that detects a motor angle and a motor angle speed of a drive motor 10 provided in a motor-driven power steering system, and the input / output interface 110 may receive information about the motor angle and the motor angle speed of the drive motor 10 output from the motor angle sensor 20. According to one embodiment, the input / output interface 110 may be connected to a steering angle sensor 40 that detects a steering angle and a steering angle speed of a steering wheel 30, and the input / output interface 110 may receive information about the steering angle and the steering angle speed of the steering wheel 30 output from the steering angle sensor 40. According to one embodiment, the input / output interface 110 may be connected to an external device configured to detect a failure of the motor angle sensor 20, and may receive a failure signal of the motor angle sensor 20 output from the external device. The external device may be configured to output a logic high signal when the motor angle sensor 20 fails, and to output a logic low signal when the motor angle sensor 20 does not fail.

[0044] The input / output interface 110 can output the result calculated by the processor 130 to an external component. According to one embodiment, the input / output interface 110 can be connected to a position controller 200 and a speed controller 300 provided in a motor-driven power steering system, and can feed back the result calculated by the processor 130 to the position controller 200 and the speed controller 300.

[0045] The memory 120 may store various information required by the processor 130 when it is running. In addition, the memory 120 may store various information calculated by the processor 130 when it is running.

[0046] The processor 130 is operably connected to the input / output interface 110 and the memory 120. The processor 130 may be implemented as a central processing unit (CPU), a micro controller unit (MCU), or a system on chip (SoC), and may be configured to control a plurality of hardware or software components connected to the processor 130 by executing an operating system or an application program, perform various data processing and calculations, execute at least one command stored in the memory 120, and store the execution result in the memory 120.

[0047] When the motor angle sensor 20 is not faulty, the processor 130 may feed back the motor angle of the drive motor 10 output from the motor angle sensor 20 to the position controller 200, and feed back the motor angle speed of the drive motor 10 output from the motor angle sensor 20 to the speed controller 300. That is, in the present embodiment, under normal circumstances where the motor angle sensor 20 is not faulty, the motor angle and the motor angle speed of the drive motor 10 detected by the motor angle sensor 20 may be used as control parameters of the position controller 200 and the speed controller 300 to perform steering control.

[0048] When the motor angle sensor 20 fails, the processor 130 may calculate a first sum value, which is a sum of a result value obtained by applying a first weight value to the motor angle of the drive motor 10 output from the motor angle sensor 20 and a result value obtained by applying a second weight value to the steering angle of the steering wheel 30 output from the steering angle sensor 40, and feed the calculated first sum value back to the position controller 200. In addition, the processor 130 may calculate a second sum value, which is a sum of a result value obtained by applying the first weight value to the motor angle speed of the drive motor 10 output from the motor angle sensor 20 and a result value obtained by applying the second weight value to the steering angle speed of the steering wheel 30 output from the steering angle sensor 40, and feed the calculated second sum value back to the speed controller 300. The processor 130 may repeatedly perform the process of calculating the first and second sum values ​​and feeding the first and second sum values ​​back to the position controller 200 and the speed controller 300 at a preset cycle.

[0049] The initial value of the first weight value (the weight value at the time point when the motor angle sensor fails) can be set to 1, and the processor 130 can repeatedly perform a process of gradually reducing the first weight value until the first weight value becomes zero, and calculating and feeding back the first and second sum values. In addition, the initial value of the second weight value can be set to zero, and the processor 130 can repeatedly perform a process of gradually increasing the second weight value until the second weight value becomes 1, and calculating and feeding back the first and second sum values. The processor 130 can set the first weight value and the second weight value so that the sum of the first weight value and the second weight value is always 1.

[0050] According to one embodiment, the processor 130 may calculate the first sum value by the following Equation 1, and calculate the second sum value by the following Equation 2.

[0051] [Equation 1]

[0052] T1=K*A1+(1-K)*B1

[0053] [Equation 2]

[0054] T2=K*A2+(1-K)*B2

[0055] Here, T1 may represent a first sum value, K may represent a first weight value, 1-K may represent a second weight value, A1 may represent a motor angle, B1 may represent a steering angle, A2 may represent a motor angle speed, and B2 may represent a steering angle speed.

[0056] In this embodiment, when the motor angle sensor 20 fails, the first steering control method in which the motor angle of the drive motor 10 is used as the control parameter of the position controller 200 and the motor angle speed of the drive motor 10 is used as the control parameter of the speed controller 300 can be switched to a second steering control method in which the steering angle of the steering wheel 30 is used as the control parameter of the position controller 200 and the steering angle speed of the steering wheel 30 is used as the control parameter of the speed controller 300.

[0057] Meanwhile, when the first steering control method is switched to the second steering control method, a sudden output change may occur as the control parameters change, thereby becoming a factor that reduces vehicle stability. Therefore, in the present embodiment, when the motor angle sensor 20 fails, instead of changing the control parameters of the position controller 200 and the speed controller 300 from the motor angle and the motor angle speed to the steering angle and the steering angle speed, the motor angle and the steering angle are mixed for a predetermined time to be fed back to the position controller 200 and the motor angle speed and the steering angle speed are mixed for a predetermined time to be fed back to the speed controller 300, thereby solving the above-mentioned problem.

[0058] The processor 130 may determine the amount of change per unit time of the first and second weight values ​​based on the steering angular velocity of the steering wheel 30. Relation information about the amount of change per unit time according to the steering angular velocity may be pre-calculated and stored in the memory 120, and the processor 130 may detect the amount of change per unit time corresponding to the steering angular velocity output from the steering angle sensor 40 from the relationship information stored in the memory 120, and use the amount of change per unit time. The amount of change per unit time of the first and second weight values ​​may be set to be larger as the steering angular velocity increases.

[0059] The processor 130 may determine the set time based on the steering angular velocity of the steering wheel 30, and calculate and feed back the first sum value and the second sum value, while gradually changing the first weight value and the second weight value so that at a time point when the set time has passed from a time point when the motor angle sensor 20 fails, the first weight value becomes 0, and the second weight value becomes 1. Relationship information about the set time according to the steering angular velocity may be pre-calculated and stored in the memory 120, and the processor 130 may detect the set time corresponding to the steering angular velocity output from the steering angle sensor 40 from the relationship information stored in the memory 120 and use the set time. The set time is a factor for determining the amount of change per hour in the first weight value and the second weight value, and may be set to be smaller as the steering angular velocity increases. According to one embodiment, as Figure 3 As shown, the setting time may be inversely proportional to the steering angle velocity. According to one embodiment, the processor 130 may set the setting time using the steering angle velocity output from the steering angle sensor 40 at the time point when the motor angle sensor 20 is determined to have failed.

[0060] In the case of a failure of the motor angle sensor 20, the control parameters need to be switched more quickly due to the large steering angular velocity. Therefore, in the present embodiment, when the steering angular velocity is relatively large, the control parameters of the position controller 200 and the speed controller 300 are switched more quickly, and when the steering angular velocity is relatively small, the control parameters of the position controller 200 and the speed controller 300 are switched more stably.

[0061] Meanwhile, the motor-driven power steering system to which the present embodiment is applied may include a position controller 200, a speed controller 300, a current controller 400, and a drive motor 10. The position controller 200 may calculate a command speed based on a command steering angle provided from an external component (e.g., an autonomous driving system) and a value fed back by the processor 130. The position controller 200 may output a command speed by compensating for the difference (i.e., a steering angle error) between the command steering angle provided externally and the value fed back by the processor 130. The command speed may be output to the speed controller 300. The position controller 200 may be a proportional integral derivative (PID) controller, but the present disclosure is not limited thereto.

[0062] The speed controller 300 may calculate a command current based on the command speed output from the position controller 200 and the value fed back by the processor 130. The speed controller 300 may output a command current by compensating for the difference (i.e., steering angular velocity error) between the command speed output from the position controller 200 and the value fed back by the processor 130. The command current may be output to the current controller 400. The speed controller 300 may be a PID controller, but the present disclosure is not limited thereto.

[0063] The current controller 400 may calculate a final command current based on the command current output from the speed controller 300 and the current value of the drive motor 10 detected by the current sensor, and may output the calculated final command current to the drive motor 10. The current controller 400 may be a PID controller, but the present disclosure is not limited thereto.

[0064] Figure 3 is a block diagram illustrating a processor according to one embodiment of the present disclosure.

[0065] refer to Figure 4 , the processor 130 may include a first filter module 131, a second filter module 132 and a mixing processing module 133. The modules in the embodiment are components responsible for some operations of the processor 130, the modules are classified according to functions, and the operations performed by each module can be understood as operations performed by the processor 130.

[0066] The first filter module 131 may remove noise included in the motor angle and the motor angle speed of the driving motor 10 output from the motor angle sensor 20. The first filter module 131 may be a low pass filter (LPF).

[0067] The second filter module 132 may remove noise included in the steering angle and the steering angular velocity of the steering wheel 30 output from the steering angle sensor 40. The second filter module 132 may be an LPF.

[0068] When the motor angle sensor 20 is not faulty, the hybrid processing module 133 may feed back the motor angle of the drive motor 10 output from the first filter module 131 to the position controller 200, and feed back the motor angle speed of the drive motor 10 output from the first filter module 131 to the speed controller 300. When the drive signal is logic low, the hybrid processing module 133 may determine that the motor angle sensor 20 is not faulty.

[0069] When the motor angle sensor 20 fails, the hybrid processing module 133 may calculate a first sum value, which is the sum of a result value obtained by applying the first weight value to the motor angle of the drive motor 10 output from the first filter module 131 and a result value obtained by applying the second weight value to the steering angle of the steering wheel 30 output from the second filter module 132, and feed the calculated first sum value back to the position controller 200. In addition, the hybrid processing module 133 may calculate a second sum value, which is the sum of a result value obtained by applying the first weight value to the motor angle speed of the drive motor 10 output from the first filter module 131 and a result value obtained by applying the second weight value to the steering angle speed of the steering wheel 30 output from the second filter module 132, and feed the calculated second sum value back to the speed controller 300. When the drive signal is logic high, the hybrid processing module 133 may determine that the motor angle sensor 20 fails.

[0070] The mixing processing module 133 may gradually reduce the first weight value until the first weight value becomes 0, and calculate and feed back the first sum value and the second sum value. The mixing processing module 133 may gradually increase the second weight value until the second first weight value becomes 1, and calculate and feed back the first sum value and the second sum value. The mixing processing module 133 may set the first weight value and the second weight value so that the sum of the first weight value and the second weight value is always 1. The initial value of the first weight value may be set to 1, and the initial value of the second weight value may be set to 0.

[0071] The hybrid processing module 133 may determine a decrease amount of the first weight value per unit time (or an increase amount of the second weight value per unit time) based on the steering angular velocity of the steering wheel 30. The hybrid processing module 133 may set the decrease amount of the first weight value per unit time (or the increase amount of the second weight value per unit time) to be greater as the steering angular velocity of the steering wheel 30 increases.

[0072] After the second weight value reaches 1, the mixing processing module 133 can feed back the steering angle of the steering wheel 30 output from the second filter module 132 to the position controller 200 without performing separate mixing processing, and feed back the steering angular velocity of the steering wheel 30 output from the second filter module 132 to the speed controller 300.

[0073] Figure 5 is a flow chart illustrating a method of controlling a motor-driven power steering system according to one embodiment of the present disclosure.

[0074] In the following, reference will be made to Figure 5A method for controlling a motor-driven power steering system according to an embodiment of the present disclosure is described. Some of the processes described below may be performed in an order different from the order described below, or may be omitted.

[0075] First, the processor 130 may determine whether the motor angle sensor 20 fails (S501). The processor 130 may determine whether the motor angle sensor 20 fails based on a fault signal received from an external component.

[0076] When the motor angle sensor 20 is not faulty, the processor 130 may feed back the motor angle of the drive motor 10 output from the motor angle sensor 20 to the position controller 200 and feed back the motor angle speed of the drive motor 10 output from the motor angle sensor 20 to the speed controller 300 ( S503 ).

[0077] When the motor angle sensor 20 fails, the processor 130 can calculate a first sum value, which is the sum of a result value obtained by applying a first weight value to the motor angle of the drive motor 10 output from the motor angle sensor 20 and a result value obtained by applying a second weight value to the steering angle of the steering wheel 30 output from the steering angle sensor 40 (S505).

[0078] Subsequently, the processor 130 may calculate a second sum value which is a sum of a result value obtained by applying the first weight value to the motor angle velocity of the drive motor 10 output from the motor angle sensor 20 and a result value obtained by applying the second weight value to the steering angle velocity of the steering wheel 30 output from the steering angle sensor 40 (S507). Operation S507 may be performed in parallel with operation S505.

[0079] Subsequently, the processor 130 may feed back the first sum value calculated in operation S505 to the position controller 200, and feed back the second sum value calculated in operation S507 to the speed controller 300 (S509). The processor 130 may repeatedly perform operations S505 to S509 while gradually reducing the first weight value and gradually increasing the second weight value. These processes may be repeated until the first weight value becomes 0 and the second weight value becomes 1. Then, the processor 130 may feed back the steering angle and steering angular velocity of the steering wheel 30 output from the steering angle sensor 40 to the position controller 200 and the speed controller 300. In this case, the processor 130 may determine the time required for the first weight value to become 0 and the second weight value to become 1 (i.e., the set time) based on the steering angular velocity of the steering wheel 30.

[0080] As described above, according to an apparatus and method for controlling a motor-driven power steering system according to an embodiment of the present disclosure, when a motor angle sensor fails, the steering control based on the motor angle is switched to the steering control based on the steering angle, so that stable steering control of the vehicle can be ensured even when the motor angle sensor fails. In addition, according to an apparatus and method for controlling a motor-driven power steering system according to an embodiment of the present disclosure, the steering control based on the motor angle is stably switched to the steering control based on the steering angle, so that unstable factors such as vibration that may occur in the process of switching from the steering control based on the motor angle sensor to the steering control based on the steering angle sensor can be minimized.

[0081] The implementation described herein may also be implemented, for example, by a method or process, a device, a software program, a data stream, or a signal. Even if only discussed in a single implementation form in the context (e.g., discussed only as a method), the implementation of the discussed features may also be implemented in other forms (e.g., a device or program). The device may be implemented with suitable hardware, software, and firmware. The method may be implemented in a device such as a processor, which is generally referred to as a processing device, including, for example, a computer, a microprocessor, an integrated circuit, or a programmable logic device. The processor also includes communication devices, such as computers, cellular phones, portable / personal digital assistants (PDAs), and other devices that facilitate information communication between end users.

[0082] According to the present disclosure, when a motor angle sensor fails, steering control based on a motor angle is switched to steering control based on a steering angle, thereby ensuring stable steering control of a vehicle even when a failure occurs in the motor angle sensor.

[0083] According to the present disclosure, motor angle-based steering control is stably switched to steering angle-based steering control, so that unstable factors such as vibrations that may occur during switching from motor angle-based steering control to steering sensor-based steering control can be minimized.

[0084] Meanwhile, it should be noted that the effects of the present disclosure are not limited to the above-mentioned effects, and other unmentioned effects of the present disclosure can be clearly understood by those skilled in the art from the above description.

[0085] Although the present disclosure has been described with reference to the embodiments shown in the accompanying drawings, these embodiments are merely illustrative, and it should be understood that those skilled in the art can derive various modifications and other equivalent embodiments based on the embodiments. Therefore, the true technical scope of the present disclosure should be limited by the technical solutions of the attached present disclosure.

Claims

1. A device for controlling a power steering system driven by a motor, the device comprising: An input / output interface connected to a motor angle sensor, a steering angle sensor, and a position controller; as well as a processor connected to the input / output interface; In which, when the motor angle sensor fails, the processor calculates the sum of a result value obtained by applying a first weight value to the motor angle of the drive motor output from the motor angle sensor and a result value obtained by applying a second weight value to the steering angle of the steering wheel output from the steering angle sensor, and feeds the sum value back to the position controller.

2. The device according to claim 1, wherein: The input / output interface is connected to a speed controller; and When the motor angle sensor fails, the processor calculates a sum of a result value obtained by applying the first weight value to the motor angle speed of the drive motor output from the motor angle sensor and a result value obtained by applying the second weight value to the steering angle speed of the steering wheel output from the steering angle sensor, and feeds the sum value back to the speed controller.

3. The device according to claim 1, wherein: The initial value of the first weight value is 1; and The processor gradually reduces the first weight value until the first weight value becomes zero.

4. The device according to claim 3, wherein: The initial value of the second weight value is 0; and The processor gradually increases the second weight value until the second weight value becomes 1.

5. The device according to claim 4, wherein: The processor sets the first weight value and the second weight value so that a sum of the first weight value and the second weight value is 1.

6. The device according to claim 4, wherein: The processor sets the amount of change per unit time of the first weight value and the second weight value based on the steering angular velocity of the steering wheel.

7. The device according to claim 6, wherein: The processor sets the amount of change per unit time to increase as the steering angular velocity of the steering wheel increases.

8. The device according to claim 1, wherein: When the motor angle sensor does not fail, the motor angle of the drive motor output from the motor angle sensor is fed back to the position controller, and the motor angle speed of the drive motor output from the motor angle sensor is fed back to the speed controller.

9. A method for controlling a motor-driven power steering system, the method being executed in a computing device including a processor, the method comprising: When a motor angle sensor fails, calculating a first result value by applying a first weight value to a motor angle of a driving motor output from the motor angle sensor; calculating a second result value by applying a second weight value to a steering angle of a steering wheel output from a steering angle sensor; as well as A sum of the first result value and the second result value is calculated, and the sum is fed back to a position controller.

10. The method according to claim 9, further comprising: calculating a third result value by applying the first weight value to the motor angle speed of the drive motor output from the motor angle sensor; calculating a fourth result value by applying the second weight value to the steering angular velocity of the steering wheel output from the steering angle sensor; as well as A sum of the third result value and the fourth result value is calculated, and the sum is fed back to the speed controller.

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