Air Spring Height Sensor Frequency Hopping for EMI Resistance
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Solution Overview
Problem
Existing air spring height sensors in vehicles are prone to faults and interference from electromagnetic interference (EMI) in noisy and vibrating environments, leading to inaccurate height measurements.
Innovation Solution
An air spring height sensor system that switches between multiple carrier frequencies to avoid interference, using a carrier frequency switching unit and evaluation unit with a frequency filter to determine if a frequency is free from interference before transmitting, allowing for accurate height measurements even in EMI-prone conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a fixed carrier frequency is used for height measurement, then the measurement system is simple, but the system is vulnerable to electromagnetic interference and faults
Solution Approach 1:
The patent applies dynamics by making the carrier frequency switchable rather than fixed. The transmitter unit can switch between different carrier frequencies (e.g., first carrier frequency and second carrier frequency) depending on interference conditions. This dynamic adaptation allows the system to avoid electromagnetic interference by changing frequencies, thereby improving reliability without requiring completely redundant measurement systems.
Solution Approach 2:
The patent changes the parameter of carrier frequency dynamically. The evaluation unit detects interference on the current carrier frequency and triggers a switch to a different carrier frequency. This parameter change enables the system to maintain reliable measurements in electromagnetic environments by selecting frequencies that are free from interference, resolving the contradiction between reliability and system complexity.
2Reliability
If the carrier frequency is switched frequently to avoid interference, then the interference resistance improves, but the measurement time increases
Solution Approach 1:
The patent applies preliminary action by having the evaluation unit continuously monitor the current carrier frequency for interference before a measurement is critically needed. When interference is detected, the system proactively switches to an alternative carrier frequency in advance, preventing measurement delays. This preliminary detection and switching mechanism reduces the actual time loss during critical measurement phases.
Solution Approach 2:
The patent implements periodic action through continuous monitoring of the carrier frequency for interference. The evaluation unit periodically checks the signal quality and triggers frequency switching when interference thresholds are exceeded. This periodic monitoring ensures that frequency switches occur only when necessary, balancing interference resistance with minimal measurement time loss.
3Measurement precision
If multiple carrier frequencies are used for measurement, then the measurement accuracy improves, but the device complexity increases
Solution Approach 1:
The patent applies universality by designing a single transceiving coil arrangement that can operate with multiple carrier frequencies. The same transmitter unit, transceiving coil, and evaluation unit handle both the first and second carrier frequencies, switching between them as needed. This multi-functional design allows the system to achieve measurement accuracy through frequency diversity without requiring separate measurement systems for each frequency, thus limiting the increase in device complexity.
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 system provides fault-resistant and interference-resistant height measurements by continuously switching between frequencies, ensuring accurate data collection and reducing the impact of EMI, thus maintaining sensor performance in challenging environments.
Implementation Method 1
a transmitter unit (102) for transmitting a height measuring signal
Implementation Method 2
a receiver unit (101) for sensing a height signal
Data Source
AI summary
The subject invention relates to an air spring height sensor comprising a transmitter unit (102) for transmitting a height measuring signal, a receiver unit (101) for sensing a height signal, a carrier frequency switching unit (103), and an evaluation unit (200). The receiver unit and the transmitter unit are adapted for being mounted to opposing mounting elements (10, 20) of an air spring (1). The transmitter unit is switchable between different carrier frequencies (121, 122) of a height measuring signal. The evaluation unit comprises a frequency filter (213) being switchable between different carrier frequencies, wherein the carrier frequency switching unit is adapted for switching the carrier frequency of the frequency filter at a predetermined first point of time and the corresponding carrier frequency of the transmitter unit at a predetermined second point of time, wherein the first point of time is prior to the second point of time.