Rail Vehicle Sensor Interference Compensation via Resonant Circuit Modes
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Inductively operating sensor devices used in railway systems for track vacancy detection are susceptible to interference from rail currents, leading to incorrect detection of magnetic field changes caused by passing wheels, and existing solutions for interference compensation are costly and prone to errors.
Innovation Solution
The sensor device operates the transmitting resonant circuit in alternating modes to differentiate between measurement signals caused by the wheel and interference, allowing for the determination and subtraction of interference variables, thereby generating compensated measured values without significant hardware additions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If inductive sensor devices are used for track occupancy detection, then wheel detection capability is provided, but susceptibility to interference from rail currents occurs
Solution Approach 1:
The transmitting resonant circuit is operated periodically in two different modes: a first mode for normal measurement and a second mode for interference measurement. By alternating between these modes, the system captures both the wheel signal and the interference signal separately, enabling accurate differentiation and compensation of the interference effect.
Solution Approach 2:
The interference component is extracted from the total measurement signal by performing a measurement in the second operating mode where only interference is present. This extracted interference signal is then subtracted from the first measurement to obtain the pure wheel detection signal, effectively separating the harmful interference from the useful measurement.
2Object-affected harmful factors
If existing interference compensation solutions are implemented, then interference immunity is improved, but hardware costs and device complexity increase
Solution Approach 1:
The sensor device performs its own interference compensation by utilizing its existing transmitting and receiving resonant circuits. The system measures interference using its own components and processes both measurements through its built-in evaluation unit, eliminating the need for separate compensation hardware and making the system self-sufficient.
Solution Approach 2:
The existing transmitting and receiving resonant circuits are made multi-functional by operating them in two different modes. The same hardware components perform both normal wheel detection and interference measurement, maximizing the utility of existing resources without adding dedicated interference compensation hardware.
3Measurement precision
If measurement periods are extended to capture interference patterns, then interference compensation accuracy improves, but sampling rate decreases
Solution Approach 1:
The interference measurement in the second operating mode is performed for a relatively short duration compared to the full wheel passage time. This partial measurement is sufficient to capture the interference pattern without requiring the entire measurement period, thus maintaining high sampling rates while achieving adequate interference compensation accuracy.
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
This approach effectively reduces interference influence on measurement results with minimal hardware expenditure, ensuring accurate detection of wheel passages without compromising sampling rate or quality.
Implementation Method 1
at least one transmitting resonant circuit for generating a magnetic field, at least one receiving resonant circuit for generating at least one measurement signal caused by the magnetic field
Implementation Method 2
operating the transmitting resonant circuit in a first period with a first operating mode and in a second period with a second operating mode different from the first operating mode
Data Source
Figure 1~2
Figure 3~4
Figure 5~6
AI summary
The invention relates to a sensor device (1) for detecting a change in the magnetic field caused by an object approaching the sensor device (1), in particular by a wheel (8) of a rail vehicle, wherein the sensor device (1) comprises at least one transmitting resonant circuit (4) for generating a magnetic field (12), at least one receiving resonant circuit (5) for generating at least one measurement signal (13) caused by the magnetic field (12) and at least one processing device (6) for processing the at least one measurement signal (13).To provide a sensor device (1) that is insensitive to interference, the invention provides that the sensor device (1) is configured for interference compensation by operating the transmitting resonant circuit (4) in a first operating mode during a first period (T1) and in a second operating mode (T2) that differs from the first operating mode, and that the processing device (6) is configured such that at least one first measured value is determined from the measurement signal (13) during the first period (T1) and at least one second measured value is determined during the second period (T2), and the first and second measured values are used to generate at least one compensated measured value. The invention also relates to a method for detecting a change in the magnetic field.