Rotorcraft Pilot Controls With Variable Friction Tactile Cueing
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Solution Overview
Problem
Rotorcrafts face challenges in providing intuitive and efficient flight control systems, especially as they become larger and more complex, with tightly coupled flight parameters requiring precise control inputs that differ significantly from fixed-wing aircraft, leading to increased pilot workload and the need for advanced tactile feedback systems to enhance stability and control.
Innovation Solution
A fly-by-wire (FBW) system that provides variable friction and force gradient tactile cues to pilots through collective and cyclic sticks, using a flight control computer to determine tactile cueing values based on stick position and operating limits, and applying these cues via friction and force elements, such as trim motors and friction devices, to mimic mechanical resistance and spring-like forces, allowing pilots to feel limits and conditions without direct mechanical connection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a fly-by-wire system is used to decouple flight control elements, then pilot workload is reduced and stability is enhanced, but the system loses direct mechanical connection and tactile feedback
Solution Approach 1:
The patent implements artificial tactile feedback systems that sense flight control stick position and generate corresponding tactile cues through friction and force elements. This feedback loop allows the pilot to perceive system state information through tactile sensations even though direct mechanical connection has been removed, thus resolving the contradiction between reduced workload and loss of tactile information.
Solution Approach 2:
The patent introduces intermediary devices including friction elements and force generating elements that act as mediators between the pilot's control inputs and the flight control system. These intermediaries transmit tactile information to the pilot without requiring direct mechanical coupling, enabling both decoupling benefits and tactile feedback preservation.
2Loss of information
If artificial tactile feedback is added to the fly-by-wire system, then tactile information is restored, but device complexity increases
Solution Approach 1:
The patent designs tactile cueing elements that serve multiple functions: they provide tactile feedback to the pilot, generate control forces, and can be integrated with existing flight control actuators. This multi-functionality reduces overall system complexity by combining several functions into unified components rather than adding separate systems.
Solution Approach 2:
The patent merges the tactile feedback generation function with the existing flight control actuation system by integrating friction elements and force generating elements into the same mechanical pathways. This consolidation reduces component count and system complexity while achieving both control and feedback functions.
3Ease of operation
If variable friction and force gradient cues are implemented, then control intuitiveness is improved, but manufacturing and system complexity increases
Solution Approach 1:
The patent implements variable friction and force gradient cues that dynamically adjust based on flight conditions and stick position. The friction coefficient and force magnitude are modulated in real-time to provide intuitive control feedback that adapts to different operating regimes, enhancing control naturalness while using programmable control logic rather than complex mechanical mechanisms.
Solution Approach 2:
The patent achieves variable tactile cues by changing system parameters including friction coefficients and force magnitudes through controlled adjustment of actuator outputs and friction element characteristics. This allows intuitive control adaptation through software-controlled parameter variation rather than complex mechanical reconfiguration.
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 FBW system reduces pilot workload by decoupling flight control elements, providing intuitive tactile feedback that enhances stability and control, allowing pilots to focus on the environment while maintaining rotorcraft stability, even during dynamic operations, and enabling customized feedback and override capabilities.
Implementation Method 1
providing a first force that is resistant to movement of the pilot control
Implementation Method 2
providing a second force on the pilot control in a direction of the threshold
Data Source
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AI summary
An rotorcraft (101) including a pilot control, a pilot control position sensor (215) connected to the pilot control and operable to generate a position signal indicating a position of the pilot control, a flight control computer (FCC) (205) in signal communication with the pilot control position sensor (215) and operable to provide a tactile cue in the pilot control in response to the position signal indicating the position of the pilot control exceeds a threshold (703) associated with an operating limit, and further operable to determine a tactile cueing value for the tactile cue according to a relationship between the position of the pilot control and the threshold (703), and generate a cue control signal according to the tactile cueing value, and a tactile cue element connected to the pilot control and in signal communication with the FCC (205) and operable to control action of the pilot control in response to the cue control signal.