Rudder control driving system current sensor fault detection and identification method based on coordinate transformation

Abstract

The invention discloses a rudder control driving system current sensor fault detection and identification method based on coordinate transformation. The method is suitable for permanent magnet synchronous servo and the situation that only two-phase current sensors are used. According to the method, the phase current of the rudder control driving system and the reference current of the control loop are converted into the first static coordinate system space and the second static coordinate system space which meet fault decoupling by adopting specific coordinate conversion, so that the fault of a certain phase current is only represented in a specific variable and is prevented from being confused with phase current faults of other channels; through designing a reasonable detection statistic and a fault detection threshold, identification of a fault channel current sensor is realized.

Description

Fault Detection and Identification Method for Current Sensor in Steering Control Drive System Based on Coordinate Transformation Technical Field

[0001] This invention belongs to the field of steering system and fault diagnosis technology, and in particular relates to a method for fault detection and identification of current sensor in steering control drive system based on coordinate transformation. Background Technology

[0002] As a critical attitude and trajectory control actuator, the performance and reliability of the rudder control drive system directly affect the safe operation and precise control of the aircraft. The current sensor, a crucial component of the rudder control drive system, undertakes key tasks such as real-time monitoring of motor current and participation in closed-loop control. However, in practical applications, current sensors face various failure risks. For example, factors such as component aging due to long-term operation, external environmental interference (e.g., electromagnetic interference, temperature changes), mechanical vibration, and installation errors can all cause measurement deviations, signal loss, or abnormal output from the current sensor. Once the current sensor fails, it not only leads to a decrease in the control accuracy of the rudder control drive system but may even cause system malfunction.

[0003] Traditional current sensor fault detection methods primarily detect whether the sum of the three-phase currents satisfies Kirchhoff's laws, i.e., whether the sum of the sampled three-phase currents is zero. While this method can detect current sensor faults promptly, it requires current sensors to be installed in all three phases, and its ability to identify and locate faulty current sensors is limited. In particular, most steering control drive systems currently only have two-phase current sensors, making the aforementioned Kirchhoff-based fault detection method difficult to apply. Although model-based approaches can estimate phase currents for current sensor fault detection, model-based designs require high accuracy in the mathematical model of the steering system. Furthermore, the detection effectiveness is significantly reduced when there are uncertainties in the model parameters. Summary of the Invention

[0004] The technical problem solved by this invention is to overcome the shortcomings of the prior art and provide a method for fault detection and identification of current sensor in steering control drive system based on coordinate transformation, so that the fault of a certain phase current is only characterized in a specific variable and will not be confused with the phase current fault of other channels, and the detection effect of sudden fault is better.

[0005] The objective of this invention is achieved through the following technical solution: a method for fault detection and identification of a current sensor in a steering control drive system based on coordinate transformation, comprising: transforming the phase current of the steering control drive system into a first stationary coordinate system to obtain a current in the transformed first stationary coordinate system; transforming the phase current of the steering control drive system into a second stationary coordinate system to obtain a current in the transformed second stationary coordinate system; transforming the reference current of the control loop into a first stationary coordinate system to obtain an estimated current value in the transformed first stationary coordinate system; transforming the reference current of the control loop into a second stationary coordinate system to obtain an estimated current value in the transformed second stationary coordinate system; obtaining a first check statistic based on the current in the transformed first stationary coordinate system and the estimated current value in the transformed first stationary coordinate system; obtaining a second check statistic based on the current in the transformed second stationary coordinate system and the estimated current value in the transformed second stationary coordinate system; obtaining a first fault detection threshold based on the first check statistic; obtaining a second fault detection threshold based on the second check statistic; and obtaining a detection and identification logic for a faulty current sensor based on the first check statistic, the first fault detection threshold, the second check statistic, and the second fault detection threshold.

[0006] In the above method for fault detection and identification of current sensor in steering control drive system based on coordinate transformation, the current in the first stationary coordinate system after transformation is obtained by the following formula: ;in, For phase b current, For phase c current, The current in phase b is in the transformed first stationary coordinate system. Let c be the phase current in the first stationary coordinate system after transformation.

[0007] In the above-mentioned method for fault detection and identification of current sensor in steering control drive system based on coordinate transformation, the current in the transformed second stationary coordinate system is obtained by the following formula: ;in, For phase b current, For phase c current, The current in phase b is in the transformed second stationary coordinate system. Let c be the phase current in the transformed second stationary coordinate system.

[0008] In the above-mentioned method for fault detection and identification of current sensor in steering control drive system based on coordinate transformation, the current estimate in the first stationary coordinate system after transformation is obtained by the following formula: ;in, The direct-axis reference current output by the controller. The quadrature-axis reference current output by the controller. This is the estimated value of the direct-axis reference current in the transformed first stationary coordinate system. This is the estimated value of the cross-axis reference current in the transformed first stationary coordinate system. This refers to the electrical angle of the servo motor.

[0009] In the above-mentioned method for fault detection and identification of current sensor in steering control drive system based on coordinate transformation, the current estimate in the transformed second stationary coordinate system is obtained by the following formula: ;in, The direct-axis reference current output by the controller. The quadrature-axis reference current output by the controller. This is the estimated value of the direct-axis reference current in the transformed first stationary coordinate system. This is the estimated value of the cross-axis reference current in the transformed first stationary coordinate system. This refers to the electrical angle of the servo motor.

[0010] In the above-mentioned method for fault detection and identification of current sensor in steering control drive system based on coordinate transformation, the first inspection statistic... It can be obtained through the following formula: ;in, The current in phase b is in the transformed first stationary coordinate system. This is the estimated value of the direct-axis reference current in the transformed first stationary coordinate system.

[0011] In the above-mentioned method for fault detection and identification of current sensor in steering control drive system based on coordinate transformation, the second inspection statistic... It can be obtained through the following formula: ;in, The current in phase b is in the transformed second stationary coordinate system. This is the estimated value of the direct-axis reference current in the transformed first stationary coordinate system.

[0012] In the above-mentioned method for fault detection and identification of current sensor in steering control drive system based on coordinate transformation, the first fault detection threshold is... It can be obtained through the following formula: ;in, As the first inspection statistic, As the first design margin, Data length for evaluation; second fault detection threshold It can be obtained through the following formula: ;in, This is the second inspection statistic. This is for the second design margin.

[0013] In the above-mentioned method for fault detection and identification of current sensors in steering control drive systems based on coordinate transformation, the detection and identification logic of the faulty current sensor is as follows: ;in, As the first inspection statistic, This is the second inspection statistic. The first fault detection threshold is set at... This is the second fault detection threshold.

[0014] A fault detection and identification system for a current sensor in a rudder control drive system based on coordinate transformation includes: a first module for transforming the phase current of the rudder control drive system into a first stationary coordinate system to obtain a current in the transformed first stationary coordinate system, and transforming the phase current of the rudder control drive system into a second stationary coordinate system to obtain a current in the transformed second stationary coordinate system; and a second module for transforming the reference current of the control loop into a reference current in the first stationary coordinate system to obtain an estimated current in the transformed first stationary coordinate system, and transforming the reference current of the control loop into an estimated current in the second stationary coordinate system. The system comprises five modules: a first module for obtaining a current estimate in a stationary coordinate system; a second module for obtaining a current estimate in a transformed first stationary coordinate system; a third module for obtaining a first check statistic based on the current in a transformed second stationary coordinate system and the current estimate in a transformed second stationary coordinate system; a fourth module for obtaining a first fault detection threshold based on the first check statistic and a second fault detection threshold based on the second check statistic; and a fifth module for obtaining the detection and identification logic of the fault current sensor based on the first check statistic, the first fault detection threshold, the second check statistic, and the second fault detection threshold.

[0015] Compared with the prior art, the present invention has the following advantages: The present invention is designed to realize the coordinate transformation of the fault channel decoupling, so that the fault of a certain phase current is only characterized in a specific variable and will not be confused with the phase current fault of other channels, and the detection effect of sudden fault is better. Attached Figure Description

[0016] Various other advantages and benefits will become apparent to those skilled in the art upon reading the following detailed description of preferred embodiments. The accompanying drawings are for illustrative purposes only and are not intended to limit the invention. Furthermore, the same reference numerals denote the same parts throughout the drawings. In the drawings: Figure 1 is a schematic diagram of a fault detection and identification design for a current sensor in a steering control drive system provided by an embodiment of the present invention; Figure 2 is a schematic diagram of a fault detection and identification design method for a current sensor in a steering control drive system provided by an embodiment of the present invention; Figure 3 is a schematic diagram of a current sensor fault detection and identification design method for a steering control drive system provided by an embodiment of the present invention; Figure 3 is a schematic diagram of a current sensor with an amplitude of... , A diagram illustrating the fault detection effect of a current sensor under a sine wave command. Detailed Implementation

[0017] Exemplary embodiments of the present disclosure will now be described in more detail with reference to the accompanying drawings. While exemplary embodiments of the present disclosure are shown in the drawings, it should be understood that the present disclosure may be implemented in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided to enable a more thorough understanding of the present disclosure and to fully convey the scope of the disclosure to those skilled in the art. It should be noted that, unless otherwise specified, the embodiments and features described herein can be combined with each other. The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0018] Considering the case of using only two-phase current sensors, researching fault detection and identification methods for current sensors in rudder control drive systems has significant practical implications. This embodiment provides a coordinate transformation-based method for fault detection and identification of current sensors in rudder control drive systems. The method includes: transforming the phase current of the rudder control drive system into a first stationary coordinate system to obtain the current in the transformed first stationary coordinate system; transforming the phase current of the rudder control drive system into a second stationary coordinate system to obtain the current in the transformed second stationary coordinate system; transforming the reference current of the control loop into a first stationary coordinate system to obtain an estimated current value in the transformed first stationary coordinate system; transforming the reference current of the control loop into a second stationary coordinate system to obtain an estimated current value in the transformed second stationary coordinate system; and obtaining a first check statistic based on the current in the transformed first stationary coordinate system and the estimated current value in the transformed first stationary coordinate system. The second check statistic is obtained based on the current in the transformed second stationary coordinate system and the current estimate in the transformed second stationary coordinate system. According to the first inspection statistic Obtain the first fault detection threshold According to the second inspection statistic Obtain the second fault detection threshold According to the first inspection statistic First fault detection threshold Second inspection statistics Second fault detection threshold The detection and identification logic of the fault current sensor is obtained.

[0019] This embodiment transforms the phase current of the steering drive system and the reference current of the control loop to the first and second stationary coordinate system spaces that satisfy fault decoupling through a specific coordinate transformation. This ensures that the fault of a certain phase current is only represented in a specific variable, avoiding confusion with the phase current faults of other channels. By designing reasonable detection statistics and fault detection thresholds, the identification of the fault channel current sensor can be achieved.

[0020] The current in the transformed first stationary coordinate system is obtained by the following formula: ;in, For phase b current, For phase c current, The current in phase b is in the transformed first stationary coordinate system. Let c be the phase current in the first stationary coordinate system after transformation.

[0021] The current in the transformed second stationary coordinate system is obtained by the following formula: ;in, For phase b current, For phase c current, The current in phase b is in the transformed second stationary coordinate system. Let c be the phase current in the transformed second stationary coordinate system.

[0022] The current estimate in the transformed first stationary coordinate system is obtained by the following formula: ;in, The direct-axis reference current output by the controller. The quadrature-axis reference current output by the controller. This is the estimated value of the direct-axis reference current in the transformed first stationary coordinate system. This is the estimated value of the cross-axis reference current in the transformed first stationary coordinate system. This refers to the electrical angle of the servo motor.

[0023] The current estimate in the transformed second stationary coordinate system is obtained by the following formula: ;in, The direct-axis reference current output by the controller. The quadrature-axis reference current output by the controller. This is the estimated value of the direct-axis reference current in the transformed first stationary coordinate system. This is the estimated value of the cross-axis reference current in the transformed first stationary coordinate system. This refers to the electrical angle of the servo motor.

[0024] First inspection statistic It can be obtained through the following formula: ;in, The current in phase b is in the transformed first stationary coordinate system. This is the estimated value of the direct-axis reference current in the transformed first stationary coordinate system.

[0025] Second inspection statistic It can be obtained through the following formula: ;in, The current in phase b is in the transformed second stationary coordinate system. This is the estimated value of the direct-axis reference current in the transformed first stationary coordinate system.

[0026] First fault detection threshold It can be obtained through the following formula: ;in, As the first inspection statistic, As the first design margin, Data length for evaluation; second fault detection threshold It can be obtained through the following formula: ;in, This is the second inspection statistic. This is for the second design margin.

[0027] The detection and identification logic of the fault current sensor is as follows: ;in, As the first inspection statistic, This is the second inspection statistic. The first fault detection threshold is set at... This is the second fault detection threshold.

[0028] This embodiment presents a fault detection and identification method for current sensors in a steering control drive system based on coordinate transformation. The design principle of the scheme is shown in Figure 1. The key design aspects are the decoupling design of the fault channel and the design of the fault detection and identification module based on coordinate transformation.

[0029] It is mainly achieved through the following technical solution: Based on the collected current sensing values ​​of the steering control drive system (considering the case of using only two-phase current sensors, taking phase b and phase c current sensing as an example) and the direct axis and quadrature axis reference currents, the fault channel is decoupled based on the coordinate transformation method, and fault detection and fault sensor identification are performed. The specific steps include: Step A1: Based on the real-time collected phase b and phase c current sensing values, the two-phase currents are transformed to the first stationary coordinate system and the second stationary coordinate system respectively using the following coordinate transformation to obtain the currents in the transformed first and second stationary coordinate systems.

[0030] ,

[0031] in, , For phase current, , The current is in the first stationary coordinate system after transformation. , The current is in the transformed second stationary coordinate system.

[0032] Step A2: Based on the real-time collected direct-axis and quadrature-axis reference current values, the direct-axis and quadrature-axis reference currents are transformed to the first stationary coordinate system and the second stationary coordinate system respectively using the following coordinate transformation to obtain the current estimate in the first stationary coordinate system after transformation.

[0033] ,

[0034] in, , The direct-axis and quadrature-axis reference currents output by the controller. , This is the estimated current value in the first stationary coordinate system after transformation. , This is the current estimate in the transformed second stationary coordinate system. This refers to the electrical angle of the servo motor.

[0035] Step A3: Calculate the inspection statistics as follows, ,

[0036] in, This is the absolute value operator.

[0037] Step A4: Assess normal conditions and The maximum value of the fluctuation is used as a basis to design an anomaly detection threshold with an added design margin. and as follows,

[0038]

[0039] in, For the length of the data used in the evaluation, This is a design margin added by human intervention.

[0040] Step A5: The detection and identification logic of the fault current sensor is designed as follows:

[0041] This implementation case is a rudder system, with a given amplitude of... , The sinusoidal command signal is injected into the b-phase current sensor channel via software to provide a 2A constant bias fault, thus meeting design verification requirements. In the design... and All are set to 0.8.

[0042] Figure 3 shows the amplitude. , The fault detection effect diagram of the current sensor under the sine wave command shows that an error occurred within the interval from the 18th second to the 22nd second. The fault was determined to be in the phase b current sensor.

[0043] This embodiment also provides a coordinate transformation-based fault detection and identification system for a current sensor in a steering control drive system. The system includes: a first module for transforming the phase current of the steering control drive system in a first stationary coordinate system to obtain a transformed current in the first stationary coordinate system, and transforming the phase current of the steering control drive system in a second stationary coordinate system to obtain a transformed current in the second stationary coordinate system; a second module for transforming the reference current of the control loop in the first stationary coordinate system to obtain a current estimate in the transformed first stationary coordinate system, and transforming the reference current of the control loop in the second stationary coordinate system to obtain a current estimate in the transformed second stationary coordinate system; and a third module for obtaining a first check statistic based on the transformed current in the first stationary coordinate system and the current estimate in the transformed first stationary coordinate system. The second check statistic is obtained based on the current in the transformed second stationary coordinate system and the current estimate in the transformed second stationary coordinate system. The fourth module is used to determine the first inspection statistic. Obtain the first fault detection threshold According to the second inspection statistic Obtain the second fault detection threshold The fifth module is used to determine the first inspection statistic. First fault detection threshold Second inspection statistics Second fault detection threshold The detection and identification logic of the fault current sensor is obtained.

[0044] This embodiment is designed to achieve coordinate transformation that can decouple fault channels, so that the fault of a certain phase current is only characterized in a specific variable and will not be confused with the phase current fault of other channels, thus achieving better detection effect for sudden faults.

[0045] Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make possible changes and modifications to the technical solutions of the present invention by utilizing the methods and techniques disclosed above without departing from the spirit and scope of the present invention. Therefore, any simple modifications, equivalent changes and alterations made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solutions of the present invention shall fall within the protection scope of the technical solutions of the present invention.

Claims

1. A method for fault detection and identification of current sensor in a steering control drive system based on coordinate transformation, characterized in that... include: The phase current of the steering control drive system is transformed into a first stationary coordinate system to obtain the current in the transformed first stationary coordinate system. The phase current of the steering control drive system is then transformed into a second stationary coordinate system to obtain the current in the transformed second stationary coordinate system. The reference current of the control loop is transformed into a first stationary coordinate system to obtain an estimated current value in the transformed first stationary coordinate system. The reference current of the control loop is then transformed into a second stationary coordinate system to obtain an estimated current value in the transformed second stationary coordinate system. A first check statistic is obtained based on the current in the transformed first stationary coordinate system and the estimated current value in the transformed first stationary coordinate system. A second check statistic is obtained based on the current in the transformed second stationary coordinate system and the estimated current value in the transformed second stationary coordinate system. A first fault detection threshold is obtained based on the first check statistic, and a second fault detection threshold is obtained based on the second check statistic. The detection and identification logic for the fault current sensor is obtained based on the first check statistic, the first fault detection threshold, the second check statistic, and the second fault detection threshold.

2. The method for fault detection and identification of current sensor in steering control drive system based on coordinate transformation according to claim 1, characterized in that: The current in the transformed first stationary coordinate system is obtained by the following formula: ;in, For phase b current, For phase c current, The current in phase b is in the transformed first stationary coordinate system. Let c be the phase current in the first stationary coordinate system after transformation.

3. The method for fault detection and identification of current sensor in steering control drive system based on coordinate transformation according to claim 1, characterized in that: The current in the transformed second stationary coordinate system is obtained by the following formula: ;in, For phase b current, For phase c current, The current in phase b is in the transformed second stationary coordinate system. Let c be the phase current in the transformed second stationary coordinate system.

4. The method for fault detection and identification of current sensor in steering control drive system based on coordinate transformation according to claim 1, characterized in that: The current estimate in the transformed first stationary coordinate system is obtained by the following formula: ;in, The direct-axis reference current output by the controller. The quadrature-axis reference current output by the controller. This is the estimated value of the direct-axis reference current in the transformed first stationary coordinate system. This is the estimated value of the cross-axis reference current in the transformed first stationary coordinate system. This refers to the electrical angle of the servo motor.

5. The method for fault detection and identification of current sensor in steering control drive system based on coordinate transformation according to claim 1, characterized in that: The current estimate in the transformed second stationary coordinate system is obtained by the following formula: ;in, The direct-axis reference current output by the controller. The quadrature-axis reference current output by the controller. This is the estimated value of the direct-axis reference current in the transformed first stationary coordinate system. This is the estimated value of the cross-axis reference current in the transformed first stationary coordinate system. This refers to the electrical angle of the servo motor.

6. The method for fault detection and identification of current sensor in steering control drive system based on coordinate transformation according to claim 1, characterized in that: First inspection statistic It can be obtained through the following formula: ;in, The current in phase b is in the transformed first stationary coordinate system. This is the estimated value of the direct-axis reference current in the transformed first stationary coordinate system.

7. The method for fault detection and identification of current sensor in steering control drive system based on coordinate transformation according to claim 1, characterized in that: Second inspection statistic It can be obtained through the following formula: ;in, The current in phase b is in the transformed second stationary coordinate system. This is the estimated value of the direct-axis reference current in the transformed first stationary coordinate system.

8. The method for fault detection and identification of current sensor in steering control drive system based on coordinate transformation according to claim 1, characterized in that: First fault detection threshold It can be obtained through the following formula: ;in, The first inspection statistic, As the first design margin, Data length for evaluation; second fault detection threshold It can be obtained through the following formula: ;in, This is the second inspection statistic. This is for the second design margin.

9. The method for fault detection and identification of current sensor in a steering control drive system based on coordinate transformation according to claim 1, characterized in that: The detection and identification logic of the fault current sensor is as follows: ;in, The first inspection statistic, This is the second inspection statistic. The first fault detection threshold is set at... This is the second fault detection threshold.

10. A fault detection and identification system for a current sensor in a steering control drive system based on coordinate transformation, characterized in that... include: The first module is used to perform coordinate transformation on the phase current of the steering control drive system in a first stationary coordinate system space to obtain the current in the transformed first stationary coordinate system, and to perform coordinate transformation on the phase current of the steering control drive system in a second stationary coordinate system space to obtain the current in the transformed second stationary coordinate system. The second module is used to perform coordinate transformation on the reference current of the control loop in a first stationary coordinate system space to obtain the current estimate in the transformed first stationary coordinate system, and to perform coordinate transformation on the reference current of the control loop in a second stationary coordinate system space to obtain the current estimate in the transformed second stationary coordinate system. The third module is used to obtain a first inspection statistic based on the current in the transformed first stationary coordinate system and the current estimate in the transformed first stationary coordinate system; and to obtain a second inspection statistic based on the current in the transformed second stationary coordinate system and the current estimate in the transformed second stationary coordinate system; the fourth module is used to obtain a first fault detection threshold based on the first inspection statistic and a second fault detection threshold based on the second inspection statistic. The fifth module is used to obtain the detection and identification logic of the fault current sensor based on the first inspection statistic, the first fault detection threshold, the second inspection statistic, and the second fault detection threshold.

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