FaultParamsExtract Module Documentation

Toolbox: RflySim PHM

Introduction

One-sentence Description: This module extracts parameters associated with a specified fault ID from input arrays of fault identifiers and corresponding parameters, and outputs a fault presence indicator.

This module serves as a fundamental preprocessing component within the RflySim PHM (Prognostics and Health Management) fault prediction and management toolchain. It enables filtering and parsing of multi-fault information output by the PX4 flight controller. In scenarios involving fault injection and PHM algorithm simulation and verification for unmanned aerial vehicles (UAVs), this module typically interfaces with batch fault data generated by PX4 or CopterSim, extracting parameters for user-specified faults to provide structured input data for subsequent fault diagnosis and health assessment algorithms.

This module can be used in conjunction with the fault injection modules, PX4 flight control simulation environment, and RflySim3D visualization environment of the RflySim platform, enabling rapid completion of information preprocessing for PHM algorithm simulation and verification, and accommodating simulation and verification requirements for various UAV actuators and sensors.

Port Descriptions

Input Ports (Inputs)

Port Name	Data Type	Dimension	Description
FaultID	double	1×1	Target fault identifier to be detected
inInts	double	1×N	[To be confirmed] Integer array storing multiple candidate fault identifiers
inFloats	double	1×N	[To be confirmed] Floating-point array corresponding one-to-one with inInts, storing fault parameters

Output Ports (Outputs)

Port Name	Data Type	Dimension	Description
hasFault	double	1×1	Detection result for the target fault: returns 1 (logical true) if the target fault is detected, otherwise returns 0 (logical false)
FaultParam	double	1×20	Stores extracted fault parameters. If the target fault is detected, the first 16 elements correspond to the fault parameters, and the last 4 elements are the final 4 values from the inFloats array; if no fault is detected, default zero values are used for padding

Parameter Configuration (Parameters)

This module has no configurable parameters.

Module Characteristics (Block Characteristics)

Characteristic	Value
Supported Data Types	double, single, int, boolean
Direct Feedthrough	Yes
Sample Time	Inherited
Code Generation Support	No

Data Communication Protocol

This module does not involve network communication.

Related Modules

Module Name	Description
ActuatorFaultInject	Injects predefined fault signals into actuators of fixed-wing UAVs
PropFaultInject	Injects predefined fault signals into motors of multi-rotor UAVs
SensorFaultInject	Injects predefined fault signals into sensors of UAVs
FaultDetectionCheck	Evaluates the accuracy rate of fault detection results for UAV sensors and actuators
PHMDataRecv	Receives raw PHM-related data from the flight controller for fault diagnosis and prediction
RULCalculate	Calculates remaining useful life (RUL) for degradation faults and outputs evaluation errors
HealthIndicatorExtract	Extracts health indicator signals during UAV system operation
FaultIDEncode	Encodes fault IDs and corresponding parameters into a standardized fault data array
MultipleFaultsExtract	Extracts parameter information for multiple faults from an encoded multi-fault data array
IMUOnlineCalibration	Implements online calibration of IMU in simulation environments
BarometerOnlineCalibration	Implements online calibration of barometers in simulation environments
GPSOnlineCalibration	Implements online calibration of GPS in simulation environments
MagnetometerOnlineCalibration	Implements online calibration of magnetometers in simulation environments
RangeFinderOnlineCalibration	Implements online calibration of ranging sensors in simulation environments
OpticalFlowOnlineCalibration	Implements online calibration of optical flow sensors in simulation environments
VIOOnlineCalibration	Implements online calibration of VIO sensors in simulation environments
ESCOnlineCalibration	Implements online calibration of electronic speed controllers (ESCs) in simulation environments

Quick Start

Minimum steps to use this module in a Simulink model.

1. Execute RegisterMatlab in MATLAB to register the RflySim PHM toolbox.
2. Locate the FaultParamsExtract module in the RflySim PHM library within the Simulink Library Browser.
3. Drag the module into your fault diagnosis simulation model and connect input/output signals according to the port definitions.

% Initialize workspace; example fault configuration
FaultID = 1; % Target fault ID to be detected

Usage Examples

Basic Usage: Detecting a Specific Actuator Stiction Fault

% Example model initialization script
% Define the target fault ID to be detected: 1 corresponds to left actuator stiction fault
targetFaultID = 1;

% Example input arrays: list of fault IDs currently present in the simulation
inputInts = [0, 1, 3]; % 0 indicates no fault, 1 indicates left actuator stiction, 3 indicates GPS signal anomaly
% Corresponding fault parameters: left actuator stiction angle is 15 degrees, GPS offset parameters are [2.5, 1.8, 0], additional status parameters are [12, 0, 0, 0]
inputFloats = [0, 15, 2.5, 1.8, 0, 12, 0, 0, 0];

In the Simulink model, after connecting `targetFaultID` to the FaultID input port and connecting `inputInts` and `inputFloats` to their respective input ports, the output `hasFault` returns `true` indicating that the target fault has been detected. The first 16 elements of the `FaultParam` array store the stuck parameter value `15`, and the last 4 elements store the final 4 values of the input `inputFloats`, i.e., `[12, 0, 0, 0]`.

### Multi-Fault Detection Scenario

```matlab
% Initialization script for sequentially detecting multiple faults
faultIDList = [1, 2, 3]; % List of fault IDs to be detected in sequence
for i = 1:length(faultIDList)
    currentFaultID = faultIDList(i);
    % Input currentFaultID into the FaultParamsExtract module to obtain whether the corresponding fault exists and its parameters
end

Notes and Common Issues

• Input Dimension Matching: The length of the inInts array must not exceed that of the inFloats array, and each fault ID in inInts must correspond to at least one parameter in inFloats; otherwise, a dimension mismatch error will occur.
• Fixed Output Array Length: The FaultParam output is always a floating-point array of fixed length 20, regardless of whether the target fault is detected; unused elements default to 0.
• Fault ID Uniqueness: If multiple identical FaultID values exist in inInts, the module returns the fault parameters corresponding to the first matching FaultID.
• Parameter Storage Rule: For a single fault, if the number of associated parameters exceeds 16, only the first 16 parameters are stored in the first 16 elements of FaultParam; the remaining parameters are truncated.
• Sample Time Matching: This module is a combinatorial logic block; it is recommended to set its sample time to match that of the fault input signals to avoid parameter read errors caused by mismatched simulation step sizes.

Change Log

• v4.10 (2024-07-24): Added the FaultParamsExtract fault parameter extraction module, supporting extraction of fault parameters corresponding to a specified FaultID from input integer and floating-point arrays.