Electromechanical Friction Device for Helicopter Flight Control
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Solution Overview
Problem
Existing flight control systems for aircraft, particularly helicopters, face issues with friction mechanisms that are mechanically complex, unreliable, and difficult to adjust, leading to discomfort and inefficiency in pilot control, especially in the absence of trim actuators.
Innovation Solution
A friction device with a contact piece that can be moved electromechanically between engaged and disengaged positions, featuring a hemispherical contact mechanism, automatic wear compensation, and adjustable friction limits, integrated into the flight control system to optimize pilot comfort and stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional friction mechanisms are used to anchor stabilization actuators, then the control stick can be held in position, but the mechanism becomes mechanically complex and unreliable
Solution Approach 1:
The patent replaces the traditional mechanical friction mechanism with an electromechanical system. A motor-driven screw mechanism actuates a friction element through a threaded connection, converting rotational motor motion into linear motion of the friction element. This substitution reduces mechanical complexity by using a controlled electromechanical actuation system instead of purely mechanical friction devices, while improving reliability through precise electronic control of the friction application.
2Ease of operation
If friction mechanisms are made accessible for adjustment, then pilot can optimize control, but the mechanism becomes more complex and harder to maintain
Solution Approach 1:
The friction mechanism is designed with self-adjusting capabilities through the electromechanical actuation system. The motor-driven screw mechanism can be controlled to automatically maintain optimal friction levels, and the system includes features that allow the pilot to make adjustments without complex procedures. The threaded connection and friction element arrangement enable simple manual adjustments when needed, while the electromechanical system handles routine optimization automatically.
3Stability of the object's composition
If friction force is increased to prevent stick movement, then control stability improves, but pilot comfort deteriorates due to difficulty in moving the stick
Solution Approach 1:
The friction mechanism is designed to be dynamic rather than static. The electromechanical actuation system continuously monitors and adjusts the friction force applied to the control stick, varying the friction level based on operational conditions. During normal flight, friction is optimized for stability, while during pilot input phases, the system reduces friction to facilitate smooth stick movement. This dynamic adjustment resolves the contradiction between stability and ease of operation.
4Duration of action of stationary object
If friction elements are made wear-resistant, then durability improves, but the mechanism becomes more complex and heavier
Solution Approach 1:
The patent incorporates a feedback mechanism that monitors the wear state of the friction elements and automatically compensates for wear accumulation. Sensors detect changes in friction element dimensions or friction force characteristics, and this information feeds back to the control system. The electromechanical actuation system then adjusts the friction element position or applied force to maintain optimal performance despite wear, extending service life without requiring complex replacement mechanisms or excessive material hardness that would increase 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 solution provides a lightweight, easily accessible, and reliable friction mechanism that enhances pilot control comfort and stability, allowing for remote engagement and disengagement, reducing wear and ensuring safe manual piloting even in case of device seizure.
Implementation Method 1
a contact piece (16) movable between a stable disengaged position and a stable engaged position and vice versa, said stable engaged position corresponding to a position in which the contact piece (16) bears against the control member (2) so as to establish a determined friction force
Data Source
Figure 1~2
Figure 3~4
Figure 5
AI summary
The device (11) has a contact piece (16) moved between a declutched stable position and a clutched stable position and vice versa. The clutched stable position corresponds to a position in which the contact piece is supported on a manual control unit (2) i.e. cyclic stick, of an aircraft in such a manner to establish a determined friction force. An electromechanical drive unit moves the contact piece between the declutched and clutched stable positions, and a remote control unit (14) activates and deactivates the drive unit. An independent claim is also included for a simplified automatic control system comprising a manual control unit acted on a control axis of an aircraft.