US-12623717-B2 - Apparatus and method for detecting failure of torque sensor for motor-driven power steering system

US12623717B2US 12623717 B2US12623717 B2US 12623717B2US-12623717-B2

Abstract

Disclosed are apparatuses and methods for detecting a failure of a torque sensor for a motor-driven power steering system, the apparatus including a processor configured to detect a failure in a first torque sensor and a second torque sensor based on main torque signals and sub-torque signals, compare a first torque value of the first torque sensor and a second torque value of the second torque sensor, in response to the first torque sensor and the second torque sensor being normal, measure an amount of change in first torque of the first torque sensor and an amount of change in second torque of the second torque sensor by applying electric current to a motor, in response to the comparison result being abnormal, and determine a failure in the first torque sensor and the second torque sensor based on the amount of change in first torque and second torque.

Inventors

Sung Kyu JE
Won Mo YANG
Ji Hoon Yoo

Assignees

HYUNDAI MOBIS CO., LTD.

Dates

Publication Date: 20260512
Application Date: 20230323
Priority Date: 20230110

Claims (12)

1 . An apparatus for detecting a failure of a torque sensor for a motor-driven power steering system, the apparatus comprising: a first torque sensor and a second torque sensor; and a processor configured to determine whether a failure exists in the first torque sensor and the second torque sensor based on main torque signals and sub-torque signals of the first torque sensor and the second torque sensor, respectively, wherein, in response to a determination that no failure exists in the first torque sensor and the second torque sensor, the processor is further configured to: compare a first torque value of the first torque sensor with a second torque value of the second torque sensor, and determine whether a result of the comparison is abnormal; in response to the comparison result being abnormal, apply an electric current to a motor of the motor-driven power steering system, the electric current having a predetermined magnitude and being applied for a predetermined time to provide a small amount of vibration in the steering system, to measure an amount of change in a first torque of the first torque sensor and an amount of change in a second torque of the second torque sensor; and determine a failure in the first torque sensor and the second torque sensor based on the respective amounts of change in the first torque and the second torque, wherein applying the electric current to the motor to determine the failure is performed only when a difference between the first torque value and the second torque value exceeds a third reference torque value and is less than or equal to a fourth reference torque value for at least a third reference time, or when the difference exceeds the fourth reference torque value for at least a fourth reference time.
2 . The apparatus of claim 1 , wherein the processor is further configured to: calculate a first difference between a column torque value of a first main torque signal of the first torque sensor and a column torque value of a first sub-torque signal of the first torque sensor; and diagnose the first torque sensor with a failure, in response to the first difference being larger than a first reference torque value and equal to or smaller than a second reference torque value for a first reference time or more or in response to the first difference being larger than the second reference torque value for a second reference time or more.
3 . The apparatus of claim 2 , wherein the processor is further configured to: calculate a second difference between a column torque value of a second main torque signal of the second torque sensor and a column torque value of a second sub-torque signal of the second torque sensor; and diagnose the second torque sensor with a failure, in response to the second difference being larger than the first reference torque value and equal to or smaller than the second reference torque value for the first reference time or more or in response to the second difference being larger than the second reference torque value for the second reference time or more.
4 . The apparatus of claim 3 , wherein the first reference torque value is smaller than the second reference torque value, and wherein the first reference time is longer than the second reference time.
5 . The apparatus of claim 1 , wherein the processor is further configured to: calculate the first torque value based on a column torque value of a first main torque signal of the first torque sensor and a column torque value of a first sub-torque signal of the first torque sensor; and calculate the second torque value based on a column torque value of a second main torque signal of the second torque sensor and a column torque value of a second sub-torque signal of the second torque sensor.
6 . The apparatus of claim 1 , wherein the processor is further configured to: determine that the first torque sensor is normal, in response to the amount of change in first torque varying; determine that the first torque sensor is failing, in response to the amount of change in first torque not varying; determine that the second torque sensor is normal, in response to the amount of change in second torque varying; and determine that the second torque sensor fails, in response to the amount of change in second torque not varying.
7 . The apparatus of claim 1 , wherein the third reference torque value is smaller than the fourth reference torque value, and wherein the third reference time is longer than the fourth reference time.
8 . The apparatus of claim 1 , wherein in response to a vehicle being turned on, the processor is further configured to: select a normal torque sensor between the first torque sensor and the second torque sensor on the basis of torque sensor failure information stored in a memory; detect failure of the normal torque sensor and other torque sensor while controlling the motor by using the torque signal from the normal torque sensor; and update the torque sensor failure information stored in the memory, in response to the vehicle being turned off.
9 . The apparatus of claim 8 , wherein the processor is further configured to: determine whether the other torque sensor is normal based on the torque sensor failure information, in response to the normal torque sensor failing; use the other torque sensor for a control process, in response to the other torque sensor being normal; and change a mode to a limp home mode or a manual mode, in response to the other torque sensor failing.
10 . A processor-implemented method of detecting a failure of a torque sensor for a motor-driven power steering system of a vehicle, the method comprising: storing torque sensor failure information in a memory; in response to a detection result indicating that a first torque sensor and a second torque sensor are normal, comparing a first torque value of the first torque sensor with a second torque value of the second torque sensor, and determining whether a result of the comparison is abnormal; in response to the comparison result being abnormal, applying an electric current to a motor of the motor-driven power steering system, the electric current having a predetermined magnitude and being applied for a predetermined time to provide a small amount of vibration in the steering system, to measure an amount of change in the first torque of the first torque sensor and an amount of change in the second torque of the second torque sensor; selecting, by a processor, a normal torque sensor from among the first torque sensor and the second torque sensor, in response to the vehicle being turned on; detecting, by the processor, a failure of at least one of the normal torque sensor or the other torque sensor while controlling the motor using a torque signal from the normal torque sensor; and updating, by the processor, the torque sensor failure information based on a failure detection result, in response to the vehicle being turned off, wherein applying the electric current to the motor to determine the failure is performed only when a difference between the first torque value and the second torque value exceeds a third reference torque value and is less than or equal to a fourth reference torque value for at least a third reference time, or when the difference exceeds the fourth reference torque value for at least a fourth reference time.
11 . The method of claim 10 , wherein the detecting of the failure further comprises: detecting a failure in the first torque sensor and the second torque sensor on the basis of main torque signals and sub-torque signals of the first torque sensor and the second torque sensor, respectively.
12 . The method of claim 10 , wherein the detection of the failure comprises: determining whether the other torque sensor is normal based on the information on the failure of the torque sensor, in response to the normal torque sensor being diagnosed with a failure; using the other torque sensor for a control process, in response to the other torque sensor being normal; and changing a mode to a limp home mode or a manual mode, in response to the other torque sensor failing.

Description

CROSS-REFERENCE TO RELATED APPLICATION This application claims the benefit under 35 USC § 119(a) of Korean Patent Application No. 10-2023-0003411, filed on Jan. 10, 2023, the entire disclosure of which are incorporated herein by reference for all purposes. BACKGROUND 1. Field The present disclosure relate to an apparatus and method for detecting a failure of a torque sensor for a motor-driven power steering system, which is capable of normally detecting a failure of a torque sensor when a torque signal within a normal range set for failure detection is transmitted even though the torque sensor is damaged by external environmental factors. 2. Description of Related Art In general, a motor-driven power steering (MDPS) system uses an electric motor and provides auxiliary torque in a direction in which a driver steers a vehicle, thereby allowing the driver to smoothly handle a steering wheel. Unlike a hydraulic power steering (HPS) system in the related art, the motor-driven power steering system automatically can control an operation of the electric motor on the basis of a traveling condition of the vehicle, thereby improving steering performance and steering operability. In this case, the motor-driven power steering system includes a torque sensor configured to measure steering torque of the driver inputted to the steering wheel, a steering angle sensor configured to measure a steering angle of the steering wheel, a vehicle speed sensor configured to measure a vehicle speed, and the like and determines the traveling condition of the vehicle. Meanwhile, recently, two torque sensors have been used for the motor-driven power steering system in order to improve a redundancy operation. In case that one torque sensor fails, the motor-driven power steering system normally operates by using the other normal torque sensor. In case that the two torque sensors fail, the motor-driven power steering system is switched to a manual mode. In this case, the failure of each of the torque sensors is detected by checking a normal range of a voltage value of a torque signal and comparing two torque voltage values in the torque sensors. That is, the detection of the failure of the torque sensor is performed by checking whether the torque voltage values of the two torque sensors are within the normal range and checking whether a torque voltage difference is within a normal range. When the voltage value deviates from the normal range, the torque sensor is diagnosed with a failure. The detection of the failure of the torque sensor may be performed in case that a voltage out of a normal range is transmitted as the torque signal is short-circuited/opened with an adjacent reference voltage, GND, or the like. However, in case that a voltage within a normal range is transmitted even though the torque sensor is damaged by external environmental factors such as water (salt or corrosion), the failure of the torque sensor cannot be normally detected. For this reason, there is a problem in that an abnormal torque value is consistently used, which causes dangerous traveling such as a self-rotation. The background technology of the present disclosure is disclosed in Korean Patent Application Laid-Open No. 2008-0078428 (published on Aug. 27, 2008 and entitled “Torque Sensor Center Point Compensation Method For Use In Electric Power Steering Apparatus”). SUMMARY This Summary is provided to introduce a selection of concepts in a simplified form that are further described below in the Detailed Description. This Summary is not intended to identify key features or essential features of the claimed subject matter, nor is it intended to be used as an aid in determining the scope of the claimed subject matter. In one general aspect, there is provided an apparatus for detecting a failure of a torque sensor for a motor-driven power steering system, the apparatus including torque sensors including a first torque sensor and a second torque sensor, and a processor configured to determine that there is not a failure in the first torque sensor and the second torque sensor on the basis of main torque signals and sub-torque signals of the first torque sensor and the second torque sensor, respectively, in response to the determining that there is not a failure in the first torque sensor and the second torque sensor, compare a first torque value of the first torque sensor and a second torque value of the second torque sensor, measure an amount of change in first torque of the first torque sensor and an amount of change in second torque of the second torque sensor by applying electric current to a motor, in response to the comparison result being abnormal, and determine a failure in the first torque sensor and the second torque sensor on the basis of the amount of change in first torque and the amount of change in second torque, respectively. The processor may be configured to calculate a first difference between a column torque value of a first main torque signal o