Inductive Resonance Sensor for Actuator Position Detection
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Solution Overview
Problem
Conventional angle or position sensors in industrial settings fail to accurately measure the exact position of actuators due to limitations in resonance-based inductive measuring systems, such as signal interference, low energy levels, and phase shifts, which restrict sampling rate and distance, and lack fail-safe mechanisms for critical industrial processes.
Innovation Solution
A sensor system utilizing an LC circuit with active excitation and multiple position indicators with distinct resonance frequencies, allowing for high-resolution position detection and fail-safe operation by generating sine and cosine signals for precise calculation and plausibility checks, and enabling measurement through metallic housings and longer distances.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If passive excitation by field is used in resonance based inductive measuring systems, then the resonant circuit can be excited, but the measuring signal is influenced by the excitation signal which limits the sampling rate
Solution Approach 1:
The patent inverts the conventional passive excitation approach by implementing active excitation where the sensor circuit board actively generates the excitation signal through an oscillator circuit, rather than relying on passive field excitation. This allows precise control of the excitation signal and separation from the measurement signal, enabling higher sampling rates without signal interference.
Solution Approach 2:
The patent introduces an intermediary oscillator circuit on the sensor circuit board that generates the excitation signal. This intermediary component mediates between the power source and the resonant circuit, providing controlled excitation that prevents signal interference and enables higher sampling rates.
2Measurement precision
If the resonant circuit has high Q-factor for strong signal, then the oscillation amplitude is sufficient, but the distance between position indicator and sensor circuit board is limited
Solution Approach 1:
The patent implements dynamic excitation frequency adjustment where the oscillator circuit on the sensor circuit board can adaptively tune the excitation frequency to match the resonant frequency of the position indicator's LC circuit. This dynamic adjustment maintains strong signal strength over varying distances by optimizing the resonant coupling conditions.
Solution Approach 2:
The patent changes the parameter of excitation frequency dynamically to match the resonant frequency of the target LC circuit. By adjusting this parameter, the system maintains high Q-factor benefits and strong signal strength even at increased distances between the sensor circuit board and position indicator.
3Measurement precision
If conventional angle or position sensors are used, then basic sensing function is provided, but accurate measurement of exact position cannot be achieved
Solution Approach 1:
The patent replaces conventional mechanical or passive inductive position sensors with an active resonant system using LC circuits and oscillators. This substitution enables precise position measurement through resonant frequency detection and signal processing, achieving high measurement accuracy while managing system complexity through integrated circuit design.
Solution Approach 2:
The sensor circuit board performs multiple functions: generating excitation signals, receiving measurement signals, processing signals to determine position, and providing fail-safe monitoring. This multi-functionality integrates what would otherwise require separate components, achieving high measurement precision without proportionally increasing device complexity.
4Use of energy by moving object
If passive excitation method is used, then the resonant circuit can operate, but energy is limited which restricts distance and causes problems with foreign material
Solution Approach 1:
The patent implements preliminary action by having the sensor circuit board generate and send the excitation signal to the position indicator before measurement begins. This active pre-excitation ensures sufficient energy is available to penetrate metal housings and overcome interference from foreign materials, enabling reliable operation in challenging industrial environments.
Solution Approach 2:
The oscillator circuit acts as an intermediary that provides controlled energy to the resonant system. This intermediary supplies sufficient energy to overcome the shielding effect of metal housings and interference from foreign materials, enabling the system to operate reliably through and around such obstacles.
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, high-resolution position detection directly on the actuator, improves signal strength and sampling rate, and ensures fail-safe operation by canceling out influencing parameters and detecting errors, suitable for industrial processes requiring accurate actuator positioning.
Implementation Method 1
a sensor PCB (106) with sensor windings (110, 112). The sensor system (100, 120, 130) operates according an inductive resonance method
Implementation Method 2
the resonant circuit of the position indicator must have a high Q-factor... the excitation signal must hit exactly the resonant frequency of the oscillating circuit
Data Source
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AI summary
A sensor system and method of operating the sensor system can include an indicator that is operable in resonance, the indicator being connected to a movable element of an actuator, and a sensor including sensor windings arranged in direct proximity to the indicator and external to a closed housing. The sensor can receive a position or an angle of the indicator, and can measure the position or the angle of the movable element inside the actuator through the closed housing based on inductive resonance facilitated by the indicator.