Single-Channel Inductive Sensing for Multiple Resonant Sensors
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Solution Overview
Problem
Existing inductive sensing systems face challenges in differentiating multiple resonant sensors and accurately determining target position or proximity due to overlapping resonant frequency states, which affects the precision of position or range sensing.
Innovation Solution
An inductance-to-digital conversion circuit and method that utilizes a single channel interface to configure multiple resonant sensors in a series-loop topology, establishing a control loop to drive each sensor to a unique resonant frequency state, allowing for distinct differentiation and accurate sensing of target positions through non-overlapping resonant frequency states.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If multiple resonant sensors are used in inductive sensing systems, then sensing coverage and measurement capability are improved, but differentiation between sensors and measurement precision deteriorate due to overlapping resonant frequency states
Solution Approach 1:
The patent applies parameter changes by dynamically adjusting the resonant frequency of each sensor through variable capacitors or variable inductors. This allows each sensor to operate at a unique, non-overlapping frequency state, enabling clear differentiation between multiple sensors while maintaining broad sensing coverage. The resonant frequency parameter is changed in real-time based on which sensor detects the target, eliminating frequency overlap issues.
2Adaptability or versatility
If multiple resonant sensors operate simultaneously, then sensing capability is enhanced, but device complexity increases due to the need for multiple interface channels
Solution Approach 1:
The patent implements universality by designing a single interface channel that can sequentially communicate with multiple resonant sensors. The system multiplexes the single channel to serve different sensors at different time slots or frequency states, allowing one interface to perform the function of multiple dedicated interfaces. This reduces device complexity while maintaining the ability to sense with multiple sensors.
Solution Approach 2:
The system employs periodic action by sequentially activating and measuring each resonant sensor in turn through the single interface channel. Each sensor is driven at its unique resonant frequency during its designated time slot, and measurements are taken periodically for each sensor. This time-division multiplexing approach allows multiple sensors to share a single interface without requiring simultaneous operation, thereby reducing interface complexity.
3Measurement precision
If resonant sensors are driven to steady-state oscillation, then sensing accuracy is improved, but energy consumption increases due to continuous excitation
Solution Approach 1:
The patent applies periodic action by driving each resonant sensor into steady-state oscillation only during its designated measurement time slot, then deactivating it. Instead of continuous excitation of all sensors, the system periodically activates individual sensors sequentially through the single interface channel. This allows each sensor to achieve the necessary steady-state oscillation for accurate measurement while minimizing overall energy consumption by ensuring sensors are active only when needed.
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
Enables precise and differentiated sensing of target positions or ranges by converting resonance control signals into sensor data, effectively differentiating between resonant sensors and providing accurate proximity or range information.
Implementation Method 1
For inductive sensing, magnetic flux energy projected from the inductive sensing coil induces eddy currents in 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
Implementation Method 3
The resonator is driven to operate at steady-state oscillation, projecting magnetic flux energy for sensing a conductive target
Data Source
Figure 1A~1B
Figure 2
Figure 3
AI summary
An inductive sensing system (10) includes multiple resonant sensors (20) interfaced to an IDC (30) through a single channel interface (31). IDC (30) establishes an IDC control loop that incorporates resonant sensors (20) as loop filters. The IDC control loop drives resonant sensors (20) 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 (30) senses changes in system resonance state representative of target-sensing conditions, and responds by driving a target-sensing system resonance state. IDC (30) converts IDC loop 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 relative to a target-sensing resonant sensor. The sensor data can be provided to a data processor (50) for proximity/range processing.