Oscillating Sensor Dynamic Gain Control
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Solution Overview
Problem
Inductive sensors face challenges in maintaining high sensitivity and adaptability due to temperature dependency and low reproducibility of non-linear semiconductor-based gain characteristics, leading to instability and reduced sensitivity in detecting objects entering their sensing range.
Innovation Solution
An oscillating sensor device with a resonance circuit and an amplifier featuring non-linear gain characteristics, controlled by a unit that sets and maintains a preset oscillation amplitude, allowing for dynamic adjustment of open loop gain to ensure high sensitivity and adaptability across varying environments.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If non-linear semiconductor effects are used to form gain characteristics, then sensitivity of detection for objects entering the sensing range is improved, but temperature dependency increases and reproducibility decreases
Solution Approach 1:
The patent replaces semiconductor-based electronic gain control with a mechanical switching system. The switch element (transistor or FET) mechanically connects or disconnects the feedback path based on the oscillation state, eliminating temperature-dependent semiconductor effects while maintaining the desired non-linear gain characteristics for sensitivity.
Solution Approach 2:
The patent introduces a switch element as an intermediary between the oscillator and feedback amplifier. This intermediary mechanically controls the feedback path based on oscillation amplitude, providing temperature-independent gain control while preserving the non-linear characteristics needed for high detection sensitivity.
2Measurement precision
If open loop gain characteristics are made too flat (constant amplification), then sensitivity for dynamic attenuation is improved, but recovery time after substantial attenuation becomes too long
Solution Approach 1:
The patent implements dynamic gain control where the feedback path is automatically switched based on real-time oscillation amplitude. During normal operation, feedback is active for high sensitivity; during substantial attenuation, feedback is reduced or disconnected to enable faster recovery, thus dynamically adapting to operational conditions.
Solution Approach 2:
The patent anticipates substantial attenuation events by monitoring oscillation amplitude and preemptively adjusting the feedback gain. When attenuation is detected, the system reduces feedback to prevent oscillation collapse and prepare for faster recovery, counteracting the harmful effect before it fully develops.
3Stability of the object's composition
If open loop gain characteristics are made too flat, then stability at operating point is improved, but no fixed operating point exists for unattenuated condition
Solution Approach 1:
The patent uses feedback from the oscillation output to control the gain of the amplifier. The feedback signal is proportional to the oscillation amplitude, and this feedback controls the gain to maintain a stable operating point, ensuring both stability and a fixed operating condition for unattenuated states.
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 solution enables high sensitivity and adaptability to environmental changes, ensuring stable operation and quick recovery from attenuation, with automatic adjustment of the operating point, reducing the need for further calibration and maintaining high sensitivity in detecting dynamic changes.
Implementation Method 1
the oscillator oscillates while the sensing coil produces an alternating magnetic field
Implementation Method 2
the presence of an object in the sensing range leads to a decrease of a quality factor of the sensing coil caused by an energy loss due to the production of eddy currents in the object
Data Source
Figure 1~2
Figure 3~4
Figure 5
AI summary
The present invention relates to an oscillating sensor device (2), particularly for a proximity sensor, for sensing a dynamic change of attenuation caused by a measurable physical effect, comprising: - an oscillator including a resonance circuit (21) and an amplifier (22) fed back to the resonance circuit (21) and configured to maintain oscillation of the oscillator wherein the amplifier (22) comprises a non-linear gain characteristics defining an operating point at a preset amplitude of oscillation, and - a control unit (3) configured to control the open loop gain of the oscillator; wherein the control unit (3) is configured to control the open loop gain of the oscillator so that the operating point is set to a preset amplitude of the oscillation.