Hybrid Actuator Force Fighting Mitigation via Adaptive Control
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Solution Overview
Problem
Hybrid actuation systems with both hydraulic and electric actuators experience force fighting due to unequal load sharing, leading to structural damage and component failure, especially when manufacturing tolerances and differences in dynamic responses between actuators are not adequately addressed.
Innovation Solution
A drive controller unit with feedforward and feedback regulators, including Linear-Quadratic-Gaussian (LQG) controllers and Model Predictive Control (MPC), is implemented to minimize force fighting by synchronizing the output position and force of actuators, using digital filters and forward-looking algorithms to anticipate and null position, force, and force transient issues.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multiple actuators with different primary power sources (hydraulic and electric) are used in a hybrid actuation system, then system versatility and functional capability are improved, but force fighting and unequal load sharing occur due to differences in dynamic response characteristics
Solution Approach 1:
The patent implements a feedback control system that continuously monitors the position and force of each actuator and adjusts their operation to minimize force fighting. The feedback regulator receives actuator position and force inputs and generates corrective signals to balance load sharing between hydraulic and electric actuators, directly addressing the reliability issue while preserving hybrid actuation benefits
Solution Approach 2:
The system dynamically changes control parameters including feedforward control gains and feedback regulator parameters based on operating conditions. By adapting these parameters in real-time, the system optimizes the dynamic response characteristics of each actuator type, enabling them to work together more effectively and reduce force fighting while maintaining the versatility of hybrid actuation
2Reliability
If feedforward and feedback control systems are implemented to minimize force fighting, then system reliability and load sharing are improved, but device complexity increases
Solution Approach 1:
The control system is segmented into distinct functional modules: feedforward controllers for each actuator, feedback regulators for each actuator, and a central coordinator. This modular segmentation allows each component to be optimized independently and simplifies the overall control architecture, reducing implementation complexity while maintaining reliable load sharing through coordinated operation of the segmented control elements
Data Source
AI summary
Systems for compensating for force fighting in multi-actuator systems are provided. A drive controller unit comprises a first feedforward controller in communication with a first actuator and configured to receive a drive command signal. A first feedback regulator is configured to output a first feedback input into the first feedforward controller, and to receive as input a first actuator position and a first actuator force. The drive controller unit further comprises a second feedforward controller in communication with a second actuator and configured to receive the drive command signal. A second feedback regulator is configured to output a second feedback input into the second feedforward controller, and to receive as input a second actuator position and a second actuator force. The drive controller unit utilizes both feedforward controllers and both feedback regulators to minimize force fighting while driving a common aileron.