Horizontal Stabilizer Trim Actuator Assembly Without Mechanical Linkage
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Solution Overview
Problem
The existing manual control systems for aircraft horizontal stabilizer trim actuators are complex, bulky, and difficult to maintain due to their mechanical linkage, which affects accuracy and maintenance efficiency.
Innovation Solution
The system replaces the mechanical linkage with motors and resolvers, allowing one of the automatic control motors to be used for manual control, providing accurate position feedback and simplifying maintenance by eliminating the need for a separate mechanical input.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a mechanical linkage system with cables and pulleys is used for manual control, then the pilot can directly control the actuator from the cockpit, but the system becomes bulky, heavy, and difficult to maintain
Solution Approach 1:
The patent replaces the mechanical linkage system (cables, pulleys, and mechanical transmission components) with an electrical control system. The manual control element generates electrical signals that are processed by a flight control computer, which then controls an actuator motor to move the stabilizer. This substitution eliminates the need for complex mechanical linkages while maintaining manual control capability, directly resolving the contradiction between ease of operation and device complexity
Solution Approach 2:
The actuator motor serves dual purposes: it functions as the actuator motor during automatic control mode and as the second motor during manual control mode. This multi-functionality eliminates the need for separate mechanical linkage systems for manual control, reducing overall system complexity while preserving both automatic and manual control capabilities
2Measurement precision
If three independent motors are used for automatic control with hydraulic valve, then accurate position control is achieved, but the system becomes complex and maintenance-intensive
Solution Approach 1:
The patent implements a control system where one of the three motors designated for automatic control can be reassigned to function as the second motor for manual control. The flight control computer manages the switching between automatic and manual modes, allowing the same motor to serve different functions based on operational requirements. This reduces the total number of motors needed while maintaining position control accuracy through electronic feedback and control algorithms
Solution Approach 2:
The system incorporates position feedback mechanisms that provide real-time information about stabilizer position to the flight control computer. This feedback enables precise position control during both automatic and manual operation, allowing the system to maintain high measurement precision while using fewer physical components. The electronic feedback loop compensates for the reduced mechanical complexity
Data Source
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AI summary
An assembly for manual control of an HSTA for controlling the position of a moveable surface, the assembly comprising a user-operated manual control element (1') e.g. a trim wheel in the cockpit, a first motor (5) and a first resolver (6) connected to the manual control element and a second motor (7) and a second resolver (8) arranged to communicate with the first motor and the first resolver and to cause corresponding movement of the actuator, in use.