Aircraft Turbine Engine Speed Control via Sensor Bypass
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Solution Overview
Problem
Aircraft turbine engines face a critical issue where closed-loop control of rotational speed is disrupted and potentially halted due to failure of position sensors, leading to loss of thrust and electrical energy generation, especially on single-engine aircraft, as existing systems rely heavily on accurate position measurements for control loops.
Innovation Solution
A control system that bypasses position sensor measurements by directly adjusting the actuator based on deviations between rotational speed setpoints and measurements, utilizing a nominal-mode and degraded-mode processing chain to maintain engine operation, including a mode management module that switches between nominal and degraded-mode control currents depending on sensor failure detection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a double control loop with position sensor is used to control rotational speed, then measurement precision is improved, but reliability deteriorates because the system stops when the position sensor fails
Solution Approach 1:
The invention extracts the position measurement function from the control loop by eliminating the position sensor dependency. The control system now determines metering slide position indirectly through the relationship between rotational speed and fuel flow rate, removing the single point of failure that caused reliability deterioration while maintaining sufficient measurement precision for control purposes
Solution Approach 2:
The rotational speed sensor serves multiple functions: it provides feedback for closed-loop control and indirectly provides position information through the speed-position relationship model. This multi-functionality eliminates the need for a separate position sensor, improving reliability while maintaining control precision
2Reliability
If two position sensors are used to detect sensor failure, then reliability is improved through redundancy, but device complexity increases
Solution Approach 1:
The invention removes the redundant position sensors and their associated failure detection logic. Instead, it uses the existing rotational speed sensor and a mathematical model to detect position-related anomalies, significantly reducing device complexity while maintaining reliability through the indirect detection method
Solution Approach 2:
The control unit acts as an intermediary that processes rotational speed data and uses it to infer position information and detect sensor failures. This intermediary approach eliminates the need for multiple position sensors while maintaining the ability to detect control system anomalies
3Productivity
If closed-loop control based on position measurement is used, then productivity is improved through better response to speed setpoint, but loss of information occurs when position sensor fails
Solution Approach 1:
The invention replaces the mechanical position sensing system with a computational approach that uses rotational speed data and a mathematical model to determine position information. This substitution maintains the closed-loop control capability and response to speed setpoints while preventing information loss by not relying on fragile position sensors
Solution Approach 2:
The system uses rotational speed feedback to continuously adjust fuel flow rate, maintaining closed-loop control without position sensors. The feedback loop ensures that the engine responds accurately to speed setpoints while the control unit monitors for anomalies that would indicate loss of position information
Data Source
AI summary
A system and method for controlling an aircraft turbine engine. The control system includes: a nominal-mode processing chain including a global corrector designed to control a speed of rotation of the turbine engine by delivering a position setpoint for a fuel metering device, and a local corrector designed to control a position of the fuel metering device by delivering a nominal-mode control current, a degraded-mode processing chain including a direct corrector designed to control the speed of rotation of the turbine engine by delivering a degraded-mode control current, and a mode management module designed to deliver, to the fuel metering device, the nominal-mode control current in the absence of failure of a position sensor measuring a position of the fuel metering device, and the degraded-mode control current in the case of failure of the position sensor.