Distance Measurement Using Imaginary Admittance
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Solution Overview
Problem
Existing proximity sensors face accuracy issues due to temperature dependencies and manufacturing tolerances in component values, affecting the precision of position readings.
Innovation Solution
A distance measurement system that determines distance between an excitation tank circuit and a resonant target circuit based on the imaginary component of the reflected admittance, which is temperature-independent, while using the real component to estimate temperature, thereby reducing variations from temperature and component tolerances.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the real component of reflected admittance is used for distance measurement, then temperature sensitivity is improved, but measurement precision deteriorates due to temperature variations
Solution Approach 1:
The reflected admittance is segmented into real and imaginary components, each serving different measurement purposes. The imaginary component is used for distance measurement to eliminate temperature dependence, while the real component is used for temperature sensing, thereby resolving the contradiction between temperature sensitivity and measurement precision.
Solution Approach 2:
The patent changes the measurement parameter from the traditional real component of impedance to the imaginary component of reflected admittance for distance measurement. This parameter change eliminates temperature dependence while maintaining distance measurement capability, and simultaneously uses the real component for temperature sensing.
2Manufacturing precision
If component values with tight tolerances are used, then manufacturing precision is improved, but device complexity and cost increase
Solution Approach 1:
The system uses the temperature sensor (real component) to self-compensate for temperature effects on component values. By continuously monitoring temperature and adjusting measurements accordingly, the system eliminates the need for tight component tolerances, reducing manufacturing complexity while maintaining measurement accuracy.
Solution Approach 2:
The patent implements feedback by using the real component of reflected admittance to sense temperature and compensating for temperature effects on the imaginary component measurements. This feedback mechanism allows the use of standard tolerance components while maintaining high measurement precision.
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 position readings with minimal variation due to temperature or component tolerances, ensuring accurate distance and temperature measurements.
Implementation Method 1
a tank circuit including a transmit coil coupled to a transmit capacitor... a target resonant circuit including a receive coil coupled to a receive capacitor. The receive coil is to receive a magnetic field generated by the tank circuit.
Implementation Method 2
Some proximity sensors operate based by exciting a tank circuit with a sinusoidal waveform. Eddy currents are induced in a nearby metal object, which in turn can be sensed in the tank circuit as a variable parallel impedance.
Data Source
AI summary
A distance measurement system includes a tank circuit including a transmit coil coupled to a transmit capacitor, a distance calculation circuit coupled to the transmit coil, and a target resonant circuit including a receive coil coupled to a receive capacitor. The receive coil is to receive a magnetic field generated by the tank circuit. The distance calculation circuit is to determine a reflected admittance. The reflected admittance includes a real component and an imaginary component. The distance calculation circuit is to determine a distance between the transmit and receive coils based on the imaginary component of the reflected admittance.