Railway Vehicle Proper Acceleration via Inertial State Estimation
Solution Overview
Problem
Existing methods for determining the proper acceleration of a railway vehicle, essential for precise positioning, rely on additional data that may be unreliable or unavailable, leading to complex system structures and susceptibility to external disturbances.
Innovation Solution
A method utilizing inertial measurements from an accelerometer and gyrometer to calculate proper acceleration, specifically tangential acceleration, through spectral analysis and state estimation, eliminating the need for external data and simplifying system complexity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If additional data (GPS, tachometer, track topology) is used to determine proper acceleration, then positioning accuracy is improved, but system complexity increases and reliability decreases due to susceptibility to external disturbances
Solution Approach 1:
The patent extracts and eliminates the dependency on external data sources (GPS, tachometer, track topology databases) from the proper acceleration determination system. By using only inertial measurements from the accelerometer and gyrometer, the system removes complex external subsystems while maintaining positioning accuracy through sophisticated signal processing of the remaining inertial data.
Solution Approach 2:
The system becomes self-sufficient by determining proper acceleration using only its onboard inertial sensors. The method processes accelerometer and gyrometer data through spectral analysis and state estimation algorithms, eliminating the need for external GPS signals, tachometer feedback, or track topology information, thereby simplifying the overall system architecture.
2Measurement precision
If additional data sources (GPS, tachometer, track topology) are integrated, then positioning accuracy is improved, but reliability worsens due to external disturbances such as weather, obstacles, and wheel slippage
Solution Approach 1:
The patent removes the system's vulnerability to external disturbances by extracting and eliminating dependencies on GPS (affected by weather and obstacles), tachometers (affected by wheel slippage), and external track topology data. The solution relies solely on inertial measurements that are immune to these external factors.
Solution Approach 2:
The system prepares for potential failures of external data sources by designing an inertial-only measurement system from the outset. The sophisticated signal processing methods (spectral analysis, state estimation) are specifically designed to extract accurate proper acceleration information from inertial sensors alone, cushioning against the unreliability of external data sources before failures occur.
3Device complexity
If inertial measurements alone are used to determine proper acceleration, then system complexity is reduced, but measurement precision deteriorates due to inability to separate proper acceleration from gravitational acceleration
Solution Approach 1:
The patent applies dynamic signal processing methods including spectral analysis to separate the proper acceleration signal from gravitational acceleration in the inertial measurements. By analyzing the frequency characteristics and temporal variations of the accelerometer and gyrometer data, the system dynamically distinguishes between motion-induced proper acceleration and constant gravitational effects.
Solution Approach 2:
The system uses state estimation with feedback mechanisms to continuously refine the separation of proper acceleration from gravitational acceleration. The estimation algorithms process the inertial measurements and provide feedback to improve the accuracy of proper acceleration determination, enabling precise positioning without external data sources.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Enables precise determination of proper acceleration and tangential acceleration solely from inertial measurements, enhancing positioning accuracy and reducing system complexity by avoiding reliance on external data sources.
Implementation Method 1
the accelerometer makes it possible to measure the actual accelerations of the railway vehicle along the axis of its movement
Implementation Method 2
the gyrometer able to measure angular accelerations around at least one axis
Data Source
Figure 1~3
AI summary
This method for calculating the self-acceleration of a railway vehicle during its movement along a railway track includes the steps of: estimating the vehicle's speed of movement using a spectral analysis of the first measurements, estimating the roll and pitch attitudes of the vehicle from the first measurements, defining a measurement vector composed of the first measurements, the second measurements, the estimated speed of movement and the estimated roll and pitch attitudes, defining a state vector having at least one component corresponding to the self-acceleration of the vehicle, applying a state estimator to estimate the state vector, and extracting the self-acceleration of the vehicle from this state vector.