Horizontal Stabilizer Trim Actuator Assembly With Resolver Feedback
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Solution Overview
Problem
Conventional manual control systems for aircraft horizontal stabilizer trim actuators are complex, bulky, and difficult to maintain due to mechanical linkages, which also result in inaccurate position feedback.
Innovation Solution
The system replaces mechanical linkages with motors and resolvers, allowing the trim wheel to directly control the actuator through electric signals, providing accurate position feedback and enabling override of automatic control for manual operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If mechanical linkages and pulleys are used for manual control, then the system can provide direct manual override capability, but the system becomes bulky, heavy, and difficult to maintain
Solution Approach 1:
The patent replaces the mechanical linkage and pulley system with an electrical control system. The manual control wheel is connected to a motor (first motor) that receives manual input, and this motor controls a second motor that actuates the stabilizer. This substitution eliminates the complex mechanical linkages while maintaining manual control capability, directly resolving the contradiction between reliability and device complexity.
2Ease of operation
If complex mechanical linkages are used to connect manual control to actuator, then manual override is achievable, but maintenance becomes time intensive and expensive
Solution Approach 1:
The electrical motor-based control system replaces the mechanical linkage system, making the system easier to maintain. Electrical components are generally simpler to diagnose and replace compared to complex mechanical linkages with multiple moving parts. The patent maintains ease of operation by keeping the manual control wheel accessible in the cockpit while simplifying the underlying control mechanism to electric motors and control circuits, directly addressing the maintenance difficulty issue.
3Measurement precision
If three independent motors with hydraulic control valve are used for automatic control, then precise position control is achieved, but the system becomes overly complex
Solution Approach 1:
The patent implements a multi-functional control system where the same motor and resolver combination serves both automatic and manual control modes. The first motor receives commands from either the flight control computer (automatic mode) or the manual control wheel (manual mode), and both modes use the same actuation mechanism through the second motor. This universal approach maintains position control accuracy while eliminating the need for separate control systems, directly resolving the complexity issue.
Solution Approach 2:
The patent uses resolvers to provide position feedback to the flight control computer, enabling precise position control. The resolvers detect the position of the stabilizer and feed this information back to the control system, allowing for accurate positioning in both automatic and manual modes. This feedback mechanism maintains measurement precision while working within a simplified control architecture.
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
This configuration simplifies maintenance, improves position feedback accuracy, and reduces system weight and complexity, making it easier to maintain and more responsive.
Implementation Method 1
a first motor and a first resolver connected to the manual control element and a second motor and a second resolver
Implementation Method 2
The transfer means comprising a first motor and a first resolver connected to the manual control element and a second motor and a second resolver
Data Source
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 and a first resolver connected to the manual control element and a second motor and a second resolver arranged to communicate with the first motor and the first resolver and to cause corresponding movement of the actuator, in use.