Variable-Pitch Blade Control for Engine Actuator Wear Reduction
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Solution Overview
Problem
Existing turbine engines experience wear issues due to frequent and rapid adjustments in operating conditions, particularly during steady-state operations, leading to premature degradation of actuators and effectors.
Innovation Solution
Implementing a controller that switches between normal and wear reduction modes, temporarily locking primary actuators and utilizing secondary effectors to manage small signal changes, thereby reducing wear and prolonging the life cycle of engine components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If frequent and rapid adjustments in operating conditions are made during steady-state operations, then engine responsiveness and adaptability are improved, but actuator and effector wear increases
Solution Approach 1:
The control system dynamically switches between normal operating mode and wear reduction mode based on detected operating conditions. In wear reduction mode, the system dynamically adjusts the bandwidth of control loops and limits the rate of change of effector positions, providing time-varying control characteristics that reduce wear during steady-state operations while maintaining responsiveness when needed
Solution Approach 2:
The system changes control parameters such as bandwidth and rate limits based on operating conditions. During wear reduction mode, the bandwidth of the effector control loop is reduced and rate limits are applied, transforming the control system's behavior from high-frequency responsive to low-frequency wear-minimizing, thereby resolving the contradiction between responsiveness and wear
2Duration of action of stationary object
If primary actuators are locked to reduce wear, then component lifespan is extended, but engine control flexibility decreases
Solution Approach 1:
The system dynamically adjusts effector bandwidth based on operating mode. In wear reduction mode, bandwidth is reduced to minimize actuator activity and extend component lifespan, while in normal mode, full bandwidth is restored to maintain complete control flexibility, allowing the system to adapt between these conflicting requirements
Solution Approach 2:
The control system introduces an intermediary layer that mediates between the locked effector state and the control demand. This intermediary adjusts the bandwidth and rate limits to allow sufficient control authority for necessary adjustments while filtering out high-frequency commands that would cause wear, thus balancing lifespan extension with control flexibility
Data Source
AI summary
An engine may include a processor communicatively coupled to a pitch actuator configured to affect a pitch of a plurality of variable pitch blades and a secondary thrust effector device. The processor is configured to change the pitch of the plurality of variable pitch blades via the pitch actuator in response to changes in a target engine parameter a normal operating mode, detect a trigger condition for a wear reduction mode, and switch from the normal operating mode to the wear reduction mode, wherein in the wear reduction mode, the pitch of the plurality of variable pitch blades is maintained at a first angle, and the secondary thrust effector device is controlled in response to the changes in the target engine parameter.