Single-Channel Inductive Sensing for Multi-Resonant Position Detection
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Solution Overview
Problem
Existing inductive sensing systems face challenges in accurately differentiating the position of multiple conductive targets due to overlapping resonant frequency states among multiple resonant sensors, which complicates the detection of target positions within a shared sensing range.
Innovation Solution
The implementation of a series-loop topology with an inductance-to-digital conversion (IDC) unit and multiple resonant sensors, each configured for unique nominal and target-sensing resonant frequency states, allows for the generation of a target-sensing resonance control signal that differentiates the position of each target relative to its respective sensor, using resonance control circuitry and loop control circuitry to drive the system to specific resonant states and output sensor data representative of the target position.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multiple resonant sensors are used to sense multiple conductive targets, then the sensing coverage and target detection capability are improved, but the resonant frequency states of different sensors overlap, making it difficult to differentiate target positions
Solution Approach 1:
The patent segments the resonant frequency spectrum by assigning each resonant sensor a unique nominal resonant frequency state. This frequency segmentation allows the IDC unit to differentiate which sensor is being actuated, thereby enabling precise target position differentiation even with multiple sensors operating simultaneously in the same physical space.
Solution Approach 2:
The patent changes the resonant frequency parameter of each sensor to be unique and non-overlapping. By configuring each resonant sensor with a distinct nominal resonant frequency state, the system ensures that when the IDC unit actuates a particular resonant frequency, only the corresponding sensor responds, eliminating frequency overlap issues and enabling accurate multi-target position sensing.
2Measurement precision
If each resonant sensor is configured with unique resonant frequency states, then target position differentiation is improved, but the system complexity and configuration requirements increase
Solution Approach 1:
The IDC unit serves multiple functions: it acts as the actuator for all resonant sensors, the controller for driving them to specific resonant frequency states, and the signal processing unit for determining target positions. This multi-functionality reduces overall system complexity despite the unique frequency configuration of each sensor.
Solution Approach 2:
The system employs feedback through the IDC unit monitoring the resonant response of each sensor. When the IDC unit drives a resonant sensor to its target-sensing resonant frequency state, the feedback signal confirms the sensor's response, enabling automatic differentiation of target positions without requiring complex manual configuration or calibration of each sensor.
3Measurement precision
If the IDC unit drives multiple resonant sensors to different resonant frequency states, then accurate target sensing is achieved, but the control loop complexity and signal processing requirements increase
Solution Approach 1:
The IDC unit employs periodic action by sequentially driving each resonant sensor to its specific resonant frequency state in a systematic manner. This periodic actuation pattern, combined with the unique frequency assignment, allows the control loop to systematically determine which sensor is responding and calculate the target position without requiring complex simultaneous multi-frequency control.
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 configuration enables precise position sensing of multiple conductive targets by ensuring non-overlapping resonant frequency states, allowing for accurate differentiation and representation of target positions through sensor data, enhancing the system's ability to detect proximity or range effectively.
Implementation Method 1
The resonator is driven to operate at steady-state oscillation, projecting magnetic flux energy for sensing a conductive target
Implementation Method 2
magnetic flux energy projected from the inductive sensing coil induces eddy currents in a conductive target within a sensing range/area of the resonant sensor
Implementation Method 3
The resonator is configured for a nominal resonant frequency state (no target present), characterized by steady-state oscillation at a resonant frequency and resonant amplitude
Data Source
AI summary
An inductive sensing system includes multiple resonant sensors interfaced to an inductance-to-digital conversion (IDC) unit through a single channel interface. IDC establishes an IDC control loop that incorporates resonant sensors as loop filters. The IDC control loop drives resonant sensors to a system resonance state in which each resonant sensor is driven to a resonant frequency state. Each resonant sensor is configured for a nominal resonant frequency state that differentiates it from the other resonant sensors. IDC senses changes in system resonance state representative of target-sensing conditions, and responds by driving a target-sensing system resonance state. IDC converts IDC loop (resonance) control signals resulting from a target-sensing condition into sensor data as representing the corresponding target-sensing resonant frequency state as an indication of target position (proximity or range) relative to a target-sensing resonant sensor. The sensor data can be provided to a data processor for proximity/range processing.