Differential Lock Actuator for Flight Surface Free-Float Control

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Solution Overview

Problem

Existing actuator systems for moving flight control surfaces in aerial vehicles face challenges such as unconstrained output motion due to mechanical disconnects, which can lead to safety issues and inefficiencies.

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

VSEngineering Contradiction Analysis

1Reliability

If velocity-summing actuators are used to allow operation even when mechanical jam occurs, then operational reliability is improved, but unconstrained motion occurs in case of mechanical disconnect

Engineering Contradiction:

Improveoperational reliabilityVSAvoidunconstrained motion

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The system dynamically switches between velocity-summing mode (for reliability during jams) and torque-summing mode (for precision during normal operation) based on operational conditions, allowing the actuator to adapt its behavior to prevent harmful unconstrained motion while maintaining reliability

Inventive Principle:

Principle #15Dynamics

2Object-affected harmful factors

If torque-summing actuators are used to prevent unconstrained motion, then safety is improved, but output jam occurs when one input source jams

Engineering Contradiction:

Improveunconstrained motionVSAvoidoperational continuity

Core Design Contradiction:

Object-affected harmful factorsVSReliability

Solution Approach 1:

Inventive Principle:

Principle #15Dynamics

3Reliability

If dual control lane actuator systems are used to provide redundancy, then safety is improved, but complex mechanical structure increases device complexity

Engineering Contradiction:

ImprovesafetyVSAvoidmechanical structure

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The differential lock mechanism serves multiple functions: it enables switching between velocity-summing and torque-summing modes, provides mechanical coupling between control lanes, and enables precise control of the flight control surface, reducing the need for separate systems for each function

Inventive Principle:

Principle #6Universality (Multi-functionality)

Data Source

PatentUS12330771B2Differential lock actuator systems and methods for moving flight control surface

Publication Date: 2025.06.17 HONEYWELL INTERNATIONAL INC

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.