Helicopter Load Estimation via Sensor Fusion
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Solution Overview
Problem
Current engine control systems for helicopters face challenges in accurately estimating engine output shaft power and maintaining constant rotor speed during aggressive flight maneuvers, while also mitigating the impact of rotor torsional resonance, which affects power delivery and flight control quality.
Innovation Solution
A control system for gas turbine engines that includes a load control module, engine control module, and a load estimation module, which uses sensor measurements and feedback signals to estimate power turbine speed, torque, and rotor load, employing algorithms such as sensor fusion and model-based estimation to integrate physical and model-based data, and filters to refine these estimates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a damping approach is used to mitigate rotor torsional resonance, then the impact of rotor resonance is reduced, but flight control quality and power delivery performance are compromised
Solution Approach 1:
The patent implements a feedback control system that uses rotor speed sensors to detect actual rotor speed deviations caused by torsional resonance. The control module processes this feedback information and adjusts fuel injection timing and quantity to counteract resonance effects in real-time, eliminating the need for damping approaches that compromise performance. This closed-loop feedback mechanism maintains flight control quality while mitigating resonance impact.
Solution Approach 2:
The patent replaces mechanical damping approaches with an electronic control system that uses sensors, processors, and fuel injection control. Instead of using mechanical elements to dampen resonance vibrations, the system uses electronic detection and electronic fuel control to actively compensate for resonance effects, thereby maintaining full power delivery capability and flight control quality without performance compromise.
2Productivity
If aggressive flight maneuvers are performed, then power demand changes rapidly, but rotor speed stability deteriorates and rotor excursions increase
Solution Approach 1:
The control system performs preliminary action by continuously monitoring engine state measurements and predicting upcoming power demand changes during aggressive maneuvers. The system proactively adjusts fuel injection parameters before rotor speed deviations occur, maintaining rotor speed stability while enabling rapid power demand response. This predictive control prevents rotor excursions rather than reacting to them after they occur.
Solution Approach 2:
The patent implements dynamic control that continuously adapts fuel injection timing and quantity based on real-time rotor speed feedback and power demand conditions. During aggressive maneuvers, the system dynamically adjusts control parameters to maintain optimal rotor speed stability while accommodating rapid power demand changes, rather than using fixed control settings that would compromise either responsiveness or stability.
3Speed
If torque and speed measurements are used directly for control, then power delivery is responsive, but measurements are disturbed by rotor resonance
Solution Approach 1:
The patent introduces an intermediary processing layer between the raw torque and speed measurements and the control decisions. The control module receives sensor measurements and processes them through algorithms that filter out resonance-induced disturbances while preserving the essential power delivery information. This intermediary processing stage cleans the measurement signals before they are used for control, maintaining both responsiveness and measurement accuracy.
Solution Approach 2:
The system creates a model-based copy or representation of the engine state that is less susceptible to resonance measurement disturbances. By comparing actual sensor measurements with model-predicted values, the control system can identify and compensate for resonance-induced measurement errors, using the cleaner model-based information for control decisions while maintaining responsive power delivery.
Data Source
AI summary
A method and control system for an aircraft using a gas turbine engine is provided. The control system includes a controller that includes a load and engine control modules and communicates control signals to a plant that includes a gas generator and a rotor load, an engine estimation module that receives engine state measurements and effector feedback/command signals from the controller and communicates a power turbine torque estimate, and a load estimation module that receives signals including the power turbine torque estimate, a first power turbine speed value, a first power turbine torque value, a second power turbine speed value, a second power turbine torque value, and a rotor speed value. The load estimation module generates one or more of a power turbine speed estimate, a power turbine torque estimate, and a rotor load estimate based on the received signals.