Variable Gain Proximity Sensor Health Monitoring for False Indications
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Solution Overview
Problem
Existing proximity sensors, particularly those using the ECKO configuration, are prone to faulty operations leading to false proximity indications, which can be costly to diagnose and rectify, increasing system weight and cost when multiple sensors are used for reliability.
Innovation Solution
A proximity sensor design incorporating a variable gain oscillator, feedback circuit, proximity determination circuit, and health monitor circuit, which maintains a constant oscillating signal amplitude and provides health status signals to ensure accurate proximity detection and sensor health assessment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multiple ECKO proximity sensors are used to detect faulty operation, then reliability is improved, but system weight and cost increase
Solution Approach 1:
The patent implements a health monitor circuit that continuously monitors the oscillating electrical signal from the variable gain oscillator and generates a health status signal. This feedback mechanism allows the system to detect faulty operation in real-time without requiring multiple sensors, thereby maintaining reliability while avoiding the weight penalty of redundant sensor arrays.
Solution Approach 2:
The proximity sensor performs self-diagnosis through the health monitor circuit, which autonomously assesses the health of the oscillator and sensor components. This self-service capability eliminates the need for external monitoring systems or multiple redundant sensors, reducing overall system weight while maintaining high reliability through continuous self-assessment.
2Reliability
If multiple ECKO proximity sensors are used to detect faulty operation, then reliability is improved, but system cost increases
Solution Approach 1:
The health monitor circuit provides continuous feedback on the operational status of the oscillator and sensor, enabling reliable fault detection with a single sensor. This approach is more cost-effective than deploying multiple expensive ECKO sensors, as it achieves the same reliability goal through intelligent monitoring rather than redundant hardware.
Solution Approach 2:
Instead of creating multiple physical sensor copies, the system creates a virtual copy of the sensor's operational state through the health status signal. This informational copy allows for reliability monitoring without the cost of additional physical sensors, effectively substituting expensive hardware redundancy with cheaper signal-based monitoring.
3Reliability
If internal diagnostic circuitry is added to a proximity sensor, then reliability is improved, but device complexity increases
Solution Approach 1:
The health monitor circuit implements a straightforward feedback loop that monitors the oscillating signal amplitude and generates a binary health status. This simple feedback mechanism provides reliable diagnostic capability without introducing complex processing logic, maintaining relatively low device complexity while achieving improved reliability.
Solution Approach 2:
The health monitor circuit uses the same oscillating electrical signal that the proximity determination circuit uses, creating a homogeneous monitoring approach. By utilizing the existing signal rather than introducing separate diagnostic signals or mechanisms, the system achieves diagnostic capability with minimal additional complexity.
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 design simplifies and cost-effectively implements diagnostic capabilities, reducing false indications and system costs by providing reliable proximity and health status signals, enhancing overall system reliability.
Implementation Method 1
The variable gain oscillator is adapted to receive electrical energy and includes a sensor coil. The variable gain oscillator has a gain that varies with the proximity of a target to the sensor coil.
Implementation Method 2
The variable gain oscillator is coupled to receive a feedback signal and is configured, in response to the feedback signal, to generate an oscillating electrical signal having a substantially constant amplitude magnitude
Implementation Method 3
One particular configuration is generally referred to as the eddy current kill oscillator (ECKO) configuration. With this configuration, the amplitude of a fixed gain oscillator is reduced or eliminated when a device or component is within a predetermined distance of the proximity sensor.
Implementation Method 4
The health monitor circuit is coupled to receive the oscillating electrical signal and is configured, in response thereto, to supply a health status signal representative of proximity sensor health.
Data Source
AI summary
A proximity sensor includes a relatively simple health monitoring circuit. The proximity sensor includes a variable gain oscillator, a feedback circuit, and a proximity determination circuit. The variable gain oscillator has a gain that varies with the proximity of a target to a sensor coil, generates an oscillating electrical signal having a substantially constant amplitude magnitude, and generates an energy signal representative of the electrical energy needed to sustain oscillations. The feedback circuit supplies feedback to the oscillator, and the proximity determination circuit, based on the energy signal, supplies a proximity signal representative of target proximity to the sensor coil. The health monitor circuit also receives the oscillating electrical signal and supplies a health status signal representative of proximity sensor health.