Coupled Resonant Proximity Sensing for Longer-Range Distance Detection
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Solution Overview
Problem
Existing proximity sensors face challenges with limited operating range and susceptibility to ambient noise, requiring complex signal conditioning and calibration, which increases cost and complexity, especially when detecting ferromagnetic targets at varying distances.
Innovation Solution
The use of specifically designed coupled resonators with active and passive tank circuits, where the electrical response is a function of distance, allowing for detection at larger distances with higher accuracy and robustness, while maintaining simplicity through a passive target circuit.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional inductance sensors are used for proximity detection, then the device structure remains simple, but the operating range is limited and measurement accuracy deteriorates at varying distances
Solution Approach 1:
The patent employs resonant oscillation of tank circuits at specific frequencies to detect proximity. The active tank circuit oscillates at a resonant frequency, and when a passive target enters the detection zone, it perturbs the oscillation, enabling detection. This resonant approach extends operating range and improves accuracy compared to traditional inductance sensors.
Solution Approach 2:
The patent changes the operating parameter from simple inductance measurement to resonant frequency detection. By using tank circuits with specific resonant frequencies and measuring changes in oscillation characteristics, the system achieves extended detection range and improved measurement precision while maintaining structural simplicity.
2Measurement precision
If complex signal conditioning and calibration circuits are added to improve detection accuracy, then measurement precision improves, but device complexity and cost increase
Solution Approach 1:
The passive target circuit serves itself by naturally responding to the active tank circuit's oscillation through magnetic coupling. No external power or complex signal processing is needed at the target side. The system uses the target's own electromagnetic response to provide detection information, eliminating the need for complex signal conditioning and calibration circuits.
Solution Approach 2:
The patent replaces complex mechanical or electronic signal conditioning systems with a simpler electromagnetic resonance-based detection method. By using resonant tank circuits, the system achieves high measurement precision through natural resonant phenomena rather than complex signal processing electronics.
3Object-affected harmful factors
If ferromagnetic targets are detected using traditional sensors, then detection capability is provided, but susceptibility to ambient noise increases and requires additional shielding
Solution Approach 1:
The use of resonant oscillation at specific frequencies creates a distinctive signal signature that is less susceptible to ambient noise. The active and passive tank circuits operate at defined resonant frequencies, allowing the system to distinguish between intentional target responses and random environmental interference, thereby reducing noise susceptibility while maintaining detection reliability.
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 enables detection at greater distances with finer resolution and higher measurement accuracy, reducing the impact of noise and maintaining simplicity, thus improving the operational range and reliability of proximity sensors.
Implementation Method 1
an active resonant tank circuit, which includes a capacitor, an inductor, and an excitation source, and a passive resonant tank circuit, which includes a capacitor and an inductor
Implementation Method 2
specifically designed coupled resonators with active and passive tank circuits, where the electrical response is a function of distance
Data Source
Figure 1
Figure 2
Figure 3A~3D
AI summary
A proximity sensor includes an active sensor (12), a passive target (14), and a measurement circuit (24). The active sensor (12) includes an active resonant tank circuit (26) that includes an excitation source, a first capacitor, and a first inductor. The passive target (14) includes a passive resonant tank circuit (34) that includes a second capacitor and a second inductor, where magnetic coupling between the first inductor and the second inductor varies as a function of physical displacement of the first inductor and the second inductor with respect to one another. The measurement circuit (24) is configured to measure a coupled resonant frequency response in the active resonant tank circuit and provide a measured distance output based on the coupled resonant frequency response.