Aircraft Mini-Stick Cam Feedback Mechanism for Force Jump Precision
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Solution Overview
Problem
Conventional force feedback mechanisms for aircraft pilot sticks, which rely on mechanical systems with springs and operating clearances, face issues of initial adjustment and drift over time due to wear and friction, making them less precise, reliable, and more expensive.
Innovation Solution
A force feedback mechanism that incorporates a cam with a profiled surface for a follower roller to simulate the desired force law with jumps, using a single spring and cam system to provide precise and reliable resistance feedback, avoiding mechanical drift and requiring fewer adjustments.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional force feedback mechanisms use multiple springs and operating clearances to achieve force jumps, then the desired force law with discontinuities can be obtained, but the mechanism suffers from initial adjustment problems and drift over time due to wear and friction
Solution Approach 1:
The patent combines multiple springs and operating clearances into a single spring system by integrating the force jump function directly into the spring's mechanical structure. The spring is designed with an inclined portion that automatically engages at specific displacement points, eliminating the need for separate springs and clearances while maintaining the desired force law with jumps.
Solution Approach 2:
The spring incorporates an inclined portion with a specific curvature profile that enables the force jump mechanism. This curved geometry allows the spring to naturally engage and disengage force transmission at predetermined points during compression, creating the discontinuous force law without requiring additional mechanical components or adjustment mechanisms.
2Adaptability or versatility
If conventional force feedback mechanisms incorporate operating clearances and multiple springs to produce force jumps, then the force law with discontinuities is achieved, but the mechanism requires frequent adjustments and is more expensive
Solution Approach 1:
The patent merges the force jump functionality into the spring's inherent geometry, eliminating the need for multiple separate springs and clearance adjustments. This single-spring design with an integrated inclined portion reduces manufacturing steps, assembly complexity, and adjustment requirements while maintaining the ability to customize force laws through geometric design.
Solution Approach 2:
The patent achieves different force laws and force jump characteristics by changing the geometric parameters of the spring's inclined portion, such as its angle, length, and curvature radius. This allows customization of the force feedback characteristics through simple geometric modifications rather than requiring complex mechanical assemblies or multiple components.
3Manufacturing precision
If conventional force feedback mechanisms use multiple springs and play in the mechanism to achieve force jumps, then the resistance force discontinuity is obtained, but the parts subjected to play wear down through friction and wear over time
Solution Approach 1:
The patent extracts and eliminates the operating clearances and multiple spring system that cause wear and friction. By using a single spring with an integrated inclined portion, the design removes the problematic play and contact interfaces between multiple components, thereby eliminating the source of friction-induced wear while maintaining precise force feedback throughout the service life.
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 mechanism achieves precise and reliable force feedback with reduced parts and assembly complexity, resulting in a more compact and economical solution.
Implementation Method 1
a spring, integrated under load, which exerts, relative to a fixed frame, an effort which is transmitted, under rolling friction, to a follower roller, pressed against it by the spring
Implementation Method 2
an effort which is transmitted, under rolling friction, to a follower roller, pressed against it by the spring
Data Source
Figure 1
Figure 2~3
Figure 4~5
AI summary
This force feedback mechanism (1) comprises a fixed frame (10) intended to be attached to an aircraft chassis, at least one spring (60, 61) opposing the movement of the mini-stick (2) relative to the frame, and mechanical motion transmission means (20, 30, 40, 41, 50, 51), carried by the frame in a movable manner and adapted to transmit a rotational movement, around a first axis of rotation (X1), between the mini-stick and said at least one spring by applying a force law according to which the resistance force, which said at least one spring opposes, via the transmission means, to the rotational movement of the mini-stick around the first axis of rotation, is dependent on the angular position of the mini-stick around the first axis of rotation, this force law comprising at least one part including at least one force jump which corresponds to a discontinuity in the intensity of the resistance force without a change in the direction of this resistance force.In order to make this force return mechanism more precise, more compact and more reliable, the transmission means include a cam (30), which is adapted to be linked to the mini-sleeve rotating about the first axis of rotation and which is provided with at least one profiled surface (32, 33) which is shaped so as to define said at least a part of the force law.