Differential Lock Actuator for Flight Control Surface Stability
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Solution Overview
Problem
Existing actuator systems for moving flight control surfaces in aerial vehicles face challenges such as unconstrained motion due to mechanical disconnects, which can lead to instability and safety issues.
Innovation Solution
A differential actuator system with a differential lock subsystem that can switch between torque-summing and velocity-summing modes, using a compound gear assembly and brakes to control the motion of the flight control surface, thereby mitigating unconstrained motion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If velocity-summing actuators are used to allow operation even when mechanical jam occurs on one input, then operational reliability is improved, but unconstrained motion occurs in case of mechanical disconnect within the drive train
Solution Approach 1:
A differential lock mechanism is introduced as an intermediary device between the two velocity-summing actuators. This differential lock can selectively couple or decouple the actuators, allowing the system to maintain velocity-summing operation under normal conditions while preventing unconstrained motion when mechanical disconnect occurs. The differential lock acts as a mediator that transitions the system between different operational states based on detected conditions.
2Stability of the object's composition
If torque-summing actuators are used to prevent unconstrained motion, then control surface stability is improved, but mechanical jam in one input results in jam of the output
Solution Approach 1:
The system dynamically switches between velocity-summing and torque-summing modes based on operational conditions. During normal operation, the system operates in velocity-summing mode for redundancy. When mechanical disconnect is detected, the differential lock engages to transition the system to torque-summing mode, preventing unconstrained motion. This dynamic adaptation allows the system to optimize between reliability and stability based on real-time conditions.
3Reliability
If dual control lane actuator systems are used to provide redundant control paths, then operational reliability is improved, but device complexity increases
Solution Approach 1:
The differential lock mechanism serves multiple functions: it enables velocity-summing operation during normal conditions, prevents unconstrained motion when disconnect occurs, and can be integrated with existing actuator systems. By making this single component multi-functional, the system achieves enhanced reliability and safety without proportionally increasing overall system complexity.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The system effectively prevents unconstrained motion of the flight control surface, ensuring stability and safety by allowing controlled movement in both torque-summing and velocity-summing modes.
Implementation Method 1
a first gear set having a first input gear driven by the first drive shaft, a first output gear configured to control the flight control surface, and a first gear train operably coupling the first input gear to the first output gear
Implementation Method 2
a differential lock subsystem operably coupled to the first gear set and the second gear set. The differential lock subsystem is switchable between a locked state to couple the first and second gear sets in a torque-summing mode and an unlocked state to couple the first and second gear sets in a velocity-summing mode
Data Source
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AI summary
A differential actuator system for controlling a flight control surface is provided, which includes a first control lane subsystem, a second control lane subsystem, a differential subsystem and a differential lock subsystem. The differential subsystem includes a first gear set forming a first load path from the first control lane to the flight control surface, and a second gear set forming a second load path from the second control lane to the flight control surface. The differential lock subsystem operably couples to the first gear set and the second gear set and is switchable between a locked state to couple the first and second gear sets in a torque-summing mode for moving the flight control surface and an unlocked state to couple the first and second gear sets in a velocity-summing mode for moving the flight control surface. Control signals issued from a controller operate the differential actuator system.