Valve Position Sensor Arbitration via Virtual Model
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Solution Overview
Problem
Existing valve position sensor redundancy systems face challenges in accurately arbitrating between multiple sensors, especially when only two sensors are available, making it difficult to determine which sensor is operating correctly.
Innovation Solution
A method and apparatus that estimate the valve position using a model representing the position as a function of pressure values from different chambers of a valve actuator, and a virtual position sensor is simulated to arbitrate between the outputs of redundant position sensors, selecting the appropriate sensor based on differences in measured and estimated positions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If redundant position sensors are used to improve reliability, then system reliability is improved, but device complexity increases
Solution Approach 1:
A model-based virtual position sensor is introduced as an intermediary to arbitrate between redundant physical sensors. The model computes an estimated valve position based on actuator control signals and physical characteristics, serving as a mediator to compare against actual sensor readings and identify faulty sensors without adding complex arbitration logic
Solution Approach 2:
A virtual copy of the position sensing function is created through mathematical modeling. Instead of relying solely on multiple physical sensors, the system creates a software-based model that replicates position detection capabilities, allowing comparison between model predictions and actual sensor readings to detect failures
2Measurement precision
If model-based position estimation is used to arbitrate between sensors, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The system changes parameters by using multiple physical characteristics of the valve actuator (pressure values from different chambers, control signals) to compute position through mathematical relationships. This approach transforms the measurement problem from direct sensor reading to parameter-based estimation, improving precision while keeping computations manageable
3Reliability
If pressure-based position estimation is used, then reliability is improved, but use of energy increases
Solution Approach 1:
The system uses existing actuator operating parameters (pressure values and control signals) that are already being measured and processed for valve control. By deriving position information from these self-generated data sources rather than additional sensors, the system improves reliability without significant additional energy consumption
Data Source
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AI summary
Example methods and apparatus to arbitrate valve position sensor redundancy are disclosed. A disclosed example method comprises measuring a first value representative of a position of a valve (115), measuring a second value (ZT1,ZT2) representative of the position of the valve, computing a first estimated position of the valve, selecting one of the first and second values based on the first estimated position, and generating a first valve control signal for the valve based on the selected one of the first and second values.