Verification method for position sensor, position sensor and vehicle electronic power steering system

Abstract

The invention provides a calibration method for a position sensor, the position sensor comprises a first sensor and a second sensor, the first sensor comprises a first chip B1 and a second chip A1, the second sensor comprises a first chip A2 and a second chip B2, the second chip A1 and the first chip A2 send a first angle signal to a microcontroller A, and the microcontroller B sends a second angle signal to a microcontroller C; and the first chip B1 and the second chip B2 send a second angle signal to the microcontroller B. The method comprises the following steps: respectively verifying the working states of the microcontroller A and the microcontroller B by using a full-bridge angle cross detection method; when the microcontroller A or the microcontroller B breaks down, the working state of the chip is verified through common-mode detection so as to determine the sensor which breaks down. According to the technical scheme, the microcontroller can accurately judge that a certain path in the MPS is abnormal, the single-point failure fault caused by the fact that the first sensor and the second sensor have faults when the faults occur is avoided, and the comprehensiveness and the safety of system detection are improved.

Description

Technical Field

[0001] The invention relates to the field of sensors, and in particular to a calibration method for a position sensor, a position sensor and a vehicle electronic power steering system. Background Art

[0002] The vehicle's motor position sensor (MPS) is used to provide the microcontrollers MCUA and MCUB with motor angle information to ensure that the motor provides the correct power assist. In the prior art, two chips are usually redundantly designed in each motor position sensor, namely the first chip and the second chip. The second chip of the first sensor and the first chip of the second sensor are connected to microcontroller A and detect the motor angle, and the first chip of the first sensor and the second chip of the second sensor are connected to microcontroller B and detect the motor angle. During fault detection, a full-bridge angle cross check (Angle Cross Check by Full Bridge) is used for any MPS. A fault in any chip in the MPS will cause the full-bridge angle cross check to obtain a fault result, so it is impossible to determine the faulty chip. As a result, a single point failure occurs, which increases the risk of power assist failure, reduces system reliability and robustness, and fails to meet the safety requirements of autonomous driving. Summary of the invention

[0003] In order to overcome the above technical defects, the purpose of the present invention is to provide a calibration method for a position sensor, so that a redundantly designed microcontroller can accurately determine whether a chip in the MPS is abnormal, thereby increasing the comprehensiveness and safety of system detection.

[0004] Specifically, the calibration method for a position sensor of the present invention, the position sensor includes a first sensor and a second sensor, the first sensor includes a first chip B1 and a second chip A1, the second sensor includes a first chip A2 and a second chip B2, the second chip A1 and the first chip A2 send a first angle signal to a microcontroller A, and the microcontroller A sends an A-channel signal according to the first angle signal; the first chip B1 and the second chip B2 send a second angle signal to a microcontroller B, and the microcontroller B sends a B-channel signal according to the second angle signal; comprising:

[0005] Use a full-bridge angle cross detection method to respectively verify the working states of the microcontroller A and the microcontroller B, and verify whether the position sensor is faulty;

[0006] When the microcontroller A or microcontroller B fails, the failed sensor is checked respectively through common mode detection.

[0007] Preferably, the working states of the microcontroller A and the microcontroller B are respectively verified using the full-bridge angle crossover, including: for the microcontroller A, verifying the working states of the first sensor and the second sensor according to the full-bridge output signal of the first chip A2 or the second chip A1;

[0008] For the microcontroller B, the working states of the first sensor and the second sensor are verified according to the full-bridge output signal of the first chip B1 or the second chip B2.

[0009] Preferably, the first angle difference θ1 between the angles measured by the first chip A2 and the second chip A1 and the second angle difference θ2 between the angles measured by the first chip B1 and the second chip B2 are calculated respectively according to formula (1) and formula (2):

[0010] θ1=AnglechipA2(θ)-AnglechipA1(θ) Formula (1);

[0011] θ2=AnglechipB1(θ)-AnglechipB2(θ) Formula (2);

[0012] Wherein, AnglechipB1(θ) and AnglechipA1(θ) are the angle values ​​measured by the first chip B1 and the second chip A1 respectively; AnglechipB2(θ) and AnglechipA2(θ) are the angle values ​​measured by the second chip B2 and the first chip A2 respectively;

[0013] When the first angle difference θ1 or the second angle difference θ2 exceeds a first threshold range, the position sensor fails.

[0014] Preferably, the full-bridge output signal is sinp(θ)+sinn(θ), where θ is the angle measured by the chip;

[0015] Detect the full-bridge output signals of the first chip A2 and the second chip A1 respectively, and the corresponding chip whose full-bridge output signal is not constant is faulty;

[0016] The full-bridge output signal of the first chip B1 or the second chip B2 is detected respectively, and the corresponding chip whose full-bridge output signal is not constant is faulty;

[0017] According to the failed chip, it is determined that the failed sensor is the first sensor and / or the second sensor.

[0018] Another aspect of the present invention provides a position sensor, which is calibrated using any of the above-mentioned calibration methods for a position sensor.

[0019] Preferably, the position sensor includes a first sensor, a second sensor and a verification module, the first sensor includes a first chip B1 and a second chip A1, the second sensor includes a first chip A2 and a second chip B2, the second chip A1 and the first chip A2 send a first angle signal to the microcontroller A, the first chip B1 and the second chip B2 send a second angle signal to the microcontroller B,

[0020] The verification module is used to continuously detect the working status of the microcontroller A and the microcontroller B using a full-bridge angle cross detection method, and when the microcontroller A or microcontroller B fails, the working status of the chip is verified respectively through common mode detection to determine the faulty sensor.

[0021] Preferably, the verification module is used to verify the working state of the chip according to the full-bridge output signal sinp(θ)+sinn(θ) of the chip, and to determine that the corresponding chip whose full-bridge output signal is non-constant is faulty, wherein θ is the angle measured by the chip, and based on the faulty chip, determine whether the faulty sensor is the first sensor and / or the second sensor.

[0022] Another aspect of the present invention provides a vehicle electronic power steering system, comprising any position sensor as described above.

[0023] After adopting the above technical solution, compared with the existing technology, the microcontroller A or B can accurately determine whether an abnormality occurs in a certain path in the MPS, rather than determining that both the first sensor and the second sensor will fail, resulting in a single-point failure. This increases the comprehensiveness, safety, reliability, robustness and robustness of system detection, reduces the risk of power assist failure, optimizes product performance, and meets the safety performance of autonomous driving. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 is a schematic diagram of a position sensor according to an embodiment of the present invention;

[0025] Figure 2 It is a detection result image of the full-bridge angle crossing detection method used in the prior art;

[0026] Figure 3 A calibration method for a position sensor according to an embodiment of the present invention;

[0027] Figure 4 for Figure 3 An image of the detection result using the common mode detection method in the embodiment;

[0028] Figure 5 FIG. 4 is a schematic diagram of a position sensor according to an embodiment of the present invention. DETAILED DESCRIPTION

[0029] The advantages of the present invention are further described below in conjunction with the accompanying drawings and specific embodiments.

[0030] Exemplary embodiments will be described in detail herein, examples of which are shown in the accompanying drawings. When the following description refers to the drawings, the same numbers in different drawings represent the same or similar elements unless otherwise indicated. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with the present disclosure. Instead, they are merely examples of devices and methods consistent with some aspects of the present disclosure as detailed in the appended claims.

[0031] The terms used in this disclosure are for the purpose of describing specific embodiments only and are not intended to limit the disclosure. The singular forms of "a", "said" and "the" used in this disclosure and the appended claims are also intended to include plural forms unless the context clearly indicates otherwise. It should also be understood that the term "and / or" used herein refers to and includes any or all possible combinations of one or more associated listed items.

[0032] It should be understood that although the terms first, second, third, etc. may be used in the present disclosure to describe various information, such information should not be limited to these terms. These terms are only used to distinguish the same type of information from each other. For example, without departing from the scope of the present disclosure, the first information may also be referred to as the second information, and similarly, the second information may also be referred to as the first information. Depending on the context, the word "if" as used herein may be interpreted as "at the time of" or "when" or "in response to determining".

[0033] An embodiment of the present invention provides a calibration method for a position sensor, such as Figure 1 As shown, the position sensor includes a first sensor MPS1 and a second sensor MPS2, the first sensor MPS1 includes a first chip B1 and a second chip A1, the second sensor MPS2 includes a first chip A2 and a second chip B2, the second chip A1 and the first chip A2 send a first angle signal to a microcontroller A (MCUA), and the first chip B1 and the second chip B2 send a second angle signal to a microcontroller B (MCUB). The method for verifying the position sensor in this embodiment includes:

[0034] Use a full-bridge angle cross detection method to respectively verify the working states of the microcontroller A and the microcontroller B, and verify whether the position sensor is faulty;

[0035] When the microcontroller A or microcontroller B fails, the working status of the chips is checked respectively through common mode detection to determine the failed sensor.

[0036] Among them, the full-bridge angle cross detection method is used to locate the sensor with working error. The full-bridge angle cross detection is also called the Wheatstone bridge working principle. The Wheatstone bridge is one of the most common and simplest bridge networks / circuits, which can be used to measure resistance very accurately. Usually the Wheatstone bridge is used with sensors to measure physical quantities such as temperature, pressure, strain, etc. The Wheatstone bridge is used in applications where small changes in resistance are measured in sensors. This is used to convert changes in resistance into voltage changes of the transducer. The combination of the bridge and the operational amplifier is widely used in industry for various sensors and transducers. For example, the resistance of a thermistor changes when the temperature changes. Similarly, the resistance of a strain gauge changes when it is subjected to pressure, force or displacement. When applied to a position sensor, the angle value of each chip can be measured more accurately using the full-bridge angle cross detection method, but when a working error occurs, it is impossible to determine which chip's angle value is correct, the first chip or the second chip. Figure 2 This is the measurement result of the full-bridge angle crossover detection method when the second chip fails.

[0037] In this embodiment, the working state of the chip is further verified by using common mode detection, and further detection and determination are performed on the faulty sensor to determine the specific faulty sensor.

[0038] In another embodiment of the present invention, Figure 3 As shown, the calibration method of the position sensor includes:

[0039] According to formula (1) and formula (2), a first angle difference θ1 between the angles measured by the first chip A2 and the second chip A1 and a second angle difference θ2 between the angles measured by the first chip B1 and the second chip B2 are calculated respectively:

[0040] θ1=AnglechipA2(θ)-AnglechipA1(θ) Formula (1);

[0041] θ2=AnglechipB1(θ)-AnglechipB2(θ) Formula (2);

[0042] Wherein, AnglechipB1(θ) and AnglechipA1(θ) are the angle values ​​measured by the first chip B1 and the second chip A1 respectively; AnglechipB2(θ) and AnglechipA2(θ) are the angle values ​​measured by the second chip B2 and the first chip A2 respectively;

[0043] When the first angle difference θ1 exceeds the first threshold range, the first sensor and the second sensor fail. When the second angle difference θ2 exceeds the first threshold range, the first sensor and the second sensor fail. Since the first chip and the second chip are redundant designs, the angle difference measured by the two chips should be within a preset threshold range, that is, the first threshold range. If it exceeds the threshold range, it can be determined that a chip has failed. It can be understood that the first threshold range can be determined by querying the functional safety manual of the chip and is a property of the chip. The thresholds (upper limit and lower limit) can be determined by querying the functional safety manual of the chip.

[0044] The full-bridge output signal is sin p (θ)+sin n (θ), where θ is the angle measured by the chip:

[0045] When the first sensor and the second sensor fail, for path A (i.e., microcontroller A): check whether the first sensor fails or the second sensor fails based on the full-bridge output signal of the common-mode detection of the first chip A2 or the second chip A1. For path B (i.e., microcontroller B): check whether the first sensor fails or the second sensor fails based on the full-bridge output signal of the common-mode detection of the first chip B1 and the second chip B2.

[0046] When the chip works normally, the value of the full-bridge output signal is a constant, such as Figure 4 As shown, when the chip works normally, the voltage value of the full-bridge output signal remains stable. Once the full-bridge output signal of the chip fluctuates, it can be considered that the chip is faulty.

[0047] Furthermore, the present method does not require the addition of hardware detection devices. It only requires the addition of detection steps for the chip of the faulty sensor through software to verify the working status of the specific chip. Combined with the redundant design of the chip and the sensor, it is possible to timely verify whether the microcontroller receiving the two-way chip signal is effective, thereby meeting the safety requirements for the vehicle's electronic power steering controller.

[0048] Another embodiment of the present invention includes a position sensor such as Figure 1 , 5As shown, the position sensor includes a first sensor, a second sensor and a verification module, the first sensor includes a first chip B1 and a second chip A1, the second sensor includes a first chip A2 and a second chip B2, the second chip A1 and the first chip A2 send a first angle signal to the microcontroller A, the first chip B1 and the second chip B2 send a second angle signal to the microcontroller B, the verification module is used to continuously detect the working status of the microcontroller A and the microcontroller B using a full-bridge angle cross detection method, and when the microcontroller A or the microcontroller B fails, the working status of the chip is respectively verified by common mode detection to determine the sensor that fails. The position sensor in this embodiment is verified using any of the verification methods for position sensors described above.

[0049] Another embodiment of the present invention includes a vehicle electronic power steering system, including the position sensor described in the above embodiment.

[0050] The technical features of the position sensor and the vehicle electronic power steering system are the same as the technical features of the above-mentioned verification method, and the present invention will not be elaborated here.

[0051] The present invention adds a common-mode detection mechanism through a software method on the basis of the original hardware, so that MCUA or MCUB can accurately determine whether a certain chip in the position sensor is abnormal, thereby increasing the comprehensiveness, safety, reliability, robustness and robustness of system detection, reducing the risk of power failure, optimizing product performance, and meeting the safety performance of autonomous driving.

[0052] It should be noted that the embodiments of the present invention have better practicability and do not impose any form of limitation on the present invention. Any technician familiar with the field may use the technical content disclosed above to change or modify it into an equivalent effective embodiment. However, any modification or equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solution of the present invention are still within the scope of the technical solution of the present invention.

Claims

1. A calibration method for a position sensor, the position sensor comprising a first sensor and a second sensor, the first sensor comprising a first chip B1 and a second chip A1, the second sensor comprising a first chip A2 and a second chip B2, the second chip A1 and the first chip A2 send a first angle signal to a microcontroller A, and the microcontroller A sends an A-path signal according to the first angle signal; the first chip B1 and the second chip B2 send a second angle signal to a microcontroller B, and the microcontroller B sends a B-path signal according to the second angle signal; characterized in that include: Use a full-bridge angle cross detection method to respectively verify the working states of the microcontroller A and the microcontroller B, and verify whether the position sensor is faulty; When the microcontroller A or microcontroller B fails, the working status of the chips is verified respectively through common mode detection to determine the failed sensor.

2. The calibration method for a position sensor according to claim 1, characterized in that: The working states of the microcontroller A and the microcontroller B are respectively verified using full-bridge angle crossover, including: For the microcontroller A, verify the working status of the first sensor and the second sensor according to the full-bridge output signal of the first chip A2 or the second chip A1; For the microcontroller B, the working states of the first sensor and the second sensor are verified according to the full-bridge output signal of the first chip B1 or the second chip B2.

3. The calibration method for a position sensor according to claim 2, characterized in that: According to formula (1) and formula (2), a first angle difference θ1 between the angles measured by the first chip A2 and the second chip A1 and a second angle difference θ2 between the angles measured by the first chip B1 and the second chip B2 are calculated respectively: θ1=AnglechipA2(θ)-AnglechipA1(θ) Formula (1); θ2=AnglechipB1(θ)-AnglechipB2(θ) Formula (2); Wherein, AnglechipB1(θ) and AnglechipA1(θ) are the angle values ​​measured by the first chip B1 and the second chip A1 respectively; AnglechipB2(θ) and Anglechip A2(θ) are the angle values ​​measured by the second chip B2 and the first chip A2 respectively; When the first angle difference θ1 or the second angle difference θ2 exceeds a first threshold range, the position sensor fails.

4. The calibration method for a position sensor according to claim 3, characterized in that: The full-bridge output signal is sinp(θ)+sinn(θ), where θ is the angle measured by the chip; Detect the full-bridge output signals of the first chip A2 and the second chip A1 respectively, and the corresponding chip whose full-bridge output signal is not a constant is faulty; The full-bridge output signal of the first chip B1 or the second chip B2 is detected respectively, and the corresponding chip whose full-bridge output signal is not constant is faulty; According to the failed chip, it is determined that the failed sensor is the first sensor and / or the second sensor.

5. A position sensor, characterized in that: The calibration is performed using the calibration method for a position sensor as described in any one of claims 1 to 4.

6. The position sensor according to claim 5, characterized in that The position sensor includes a first sensor, a second sensor and a verification module. The first sensor includes a first chip B1 and a second chip A1. The second sensor includes a first chip A2 and a second chip B2. The second chip A1 and the first chip A2 send a first angle signal to the microcontroller A. The first chip B1 and the second chip B2 send a second angle signal to the microcontroller B. The verification module is used to continuously detect the working status of the microcontroller A and the microcontroller B using a full-bridge angle cross detection method, and when the microcontroller A or microcontroller B fails, the working status of the chip is verified respectively through common mode detection to determine the faulty sensor.

7. The position sensor according to claim 6, characterized in that The verification module is used to verify the working state of the chip according to the full-bridge output signal sinp(θ)+sinn(θ) of the chip, and to determine that the corresponding chip whose full-bridge output signal is non-constant is faulty, wherein θ is the angle measured by the chip, and according to the faulty chip, determine whether the faulty sensor is the first sensor and / or the second sensor.

8. A vehicle electronic power steering system, characterized in that: Comprising a position sensor as described in any one of claims 5-7.

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