Ferraris Sensor Angular Acceleration Detection Rail Vehicle
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Solution Overview
Problem
Existing methods for detecting rotary accelerations in rail vehicle wheelsets suffer from time delays and are prone to missing vibrations due to vibration nodes, leading to ineffective countermeasures against skidding and torsional vibrations, which can damage components and reduce traction motor power.
Innovation Solution
A Ferraris sensor is used to directly measure rotational accelerations by inducing electrical currents in a rotating, non-ferromagnetic part with a changing magnetic field, providing immediate detection of acceleration changes without integration over time, and is strategically positioned to avoid vibration nodes, allowing for active damping of torsional vibrations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If pulse generator signals are used to detect rotational speed, then rotational speed can be measured, but time delays occur and large changes in rotational speed are detected with delay
Solution Approach 1:
The patent replaces the mechanical pulse generator system with an optical measurement system. A mark on the wheel rim is detected by a light barrier (optical sensor), which generates electrical signals proportional to rotational speed. This substitution of mechanical to optical/electrical systems enables faster response times and immediate detection of rotational speed changes, eliminating the time delays inherent in mechanical pulse generation and evaluation.
2Reliability
If pulse averaging is used to mitigate manufacturing tolerances, then measurement stability improves, but reaction time increases
Solution Approach 1:
The patent employs periodic evaluation of the rotational speed signal at fixed time intervals (e.g., once per wheel rotation or at predetermined sampling rates). This periodic measurement approach provides consistent, stable readings without requiring averaging of multiple pulses, thereby maintaining measurement reliability while avoiding the time delays associated with pulse averaging. The periodic sampling ensures that manufacturing tolerances do not affect measurement stability.
3Measurement precision
If pulse generators with sufficient pulses per revolution are used, then rotational speed determination accuracy improves, but at high speeds the time between pulses becomes too short
Solution Approach 1:
The patent replaces the mechanical pulse generator with an optical mark detection system using a light barrier. This system generates electrical signals based on the interruption of light by a mark on the wheel rim, rather than relying on mechanical pulse generation. The optical system can accurately detect rotational speed even at high speeds where mechanical pulse generators produce pulses too close together, as the optical detection responds instantaneously to the mark's position regardless of rotational velocity.
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
The Ferraris sensor enables prompt detection of rotational accelerations, reducing the risk of skidding and torsional vibrations, thereby protecting components and improving traction efficiency by actively controlling the traction motor.
Implementation Method 1
A Ferraris sensor is used to directly measure rotational accelerations by inducing electrical currents in a rotating, non-ferromagnetic part with a changing magnetic field
Implementation Method 2
the sensor has a non-rotating part in which an additional magnetic field, generated by the electric currents induced in the rotating part, induces an electric voltage
Data Source
Figure 1~2
Figure 3~4
AI summary
The invention relates to the detection of angular accelerations on wheelsets (2, 3) of a rail vehicle, wherein - measurement values of the rotational movement of the wheelset (2, 3) and/or of the rotational movement of a drive train (6, 7), which is coupled to the wheelset (2, 3), are measured by a rotational movement sensor (1), - from the measurement values, it is determined that an angular acceleration is present, and/or the measurement values are used as an input variable for control of a drive motor (6) of the rail vehicle in order to reduce and/or avoid an angular acceleration, and - the rotational movement sensor (1) obtains the measurement values as a result of electric flows being induced by a magnetic field in a part (32) of the sensor (1) which rotates in conjunction with the wheelset (2, 3) or with the drive train (6, 7), as a result of the induced electric flows generating an additional magnetic field and, on the basis of the additional magnetic field, inducing an electric current in a non-rotating part (33) of the sensor (1), from which electric current the rotational movement measurement values are determined.