Variable Damping Coefficient for Hybrid Helicopter Flight Control Linkage
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Solution Overview
Problem
Hybrid helicopters face challenges in providing effective haptic feedback to pilots, especially at high speeds, which can lead to pitching-up phenomena and excessive load factors, compromising safety and accuracy due to the lack of tactile sensation of reaction forces from airfoil surfaces.
Innovation Solution
A method and system for variable-coefficient damping in the flight-attitude changing linkage of a hybrid helicopter, using a rotary damper with a variable damping coefficient that adjusts based on the instantaneous load factor and thrust position, providing haptic feedback to the pilot through the manual flight control device to maintain load factors within limits.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If constant damping is applied to flight control, then the control response is stable, but haptic feedback accuracy deteriorates at varying load factors
Solution Approach 1:
The patent implements a variable damping coefficient that dynamically adjusts based on the instantaneous load factor. The damping coefficient λ is calculated as λ = λ₀ × (n_z / n_z0), where λ₀ is the reference damping coefficient, n_z is the instantaneous load factor, and n_z0 is the reference load factor. This dynamic adjustment ensures optimal haptic feedback accuracy across varying flight conditions while maintaining control stability.
Solution Approach 2:
The patent changes the damping parameter from a constant value to a variable value that depends on the load factor. By modifying the damping coefficient according to the load factor ratio, the system adapts to different flight conditions, providing accurate haptic feedback whether the aircraft is experiencing high or low load factors.
2Reliability
If high damping force is applied to prevent pitching-up, then flight safety improves, but pilot comfort and control accuracy deteriorate
Solution Approach 1:
The system dynamically adjusts damping forces based on real-time load factor measurements. During normal flight conditions with moderate load factors, the damping coefficient remains low, providing smooth control and pilot comfort. When the load factor approaches critical thresholds that could cause pitching-up, the damping coefficient increases automatically, providing stronger stabilizing forces to ensure flight safety.
Solution Approach 2:
The damping parameter is changed from a fixed high value to a variable value that scales with the load factor. This allows the system to provide minimal damping during comfortable flight conditions and maximal damping only when necessary for safety, optimizing both pilot comfort and flight reliability.
3Ease of operation
If low damping is applied for smooth control, then pilot comfort improves, but the risk of excessive load factors and pitching-up increases
Solution Approach 1:
The system continuously monitors the instantaneous load factor n_z and uses this feedback to adjust the damping coefficient in real-time. When the load factor remains within normal ranges, low damping is maintained for pilot comfort. When the load factor approaches dangerous thresholds, the feedback loop triggers an increase in damping coefficient to prevent pitching-up, thus eliminating the need to choose between comfort and safety.
4Measurement precision
If variable damping coefficient is used to improve haptic feedback, then device complexity increases
Solution Approach 1:
The patent replaces complex mechanical variable damping mechanisms with an electronic control system. A load factor sensor measures n_z, and an electronic controller calculates the appropriate damping coefficient and actuates the damping device accordingly. This substitution of mechanical complexity with electronic control achieves variable damping functionality while simplifying the overall system architecture.
Solution Approach 2:
The system introduces an electronic control unit as an intermediary between the load factor sensor and the damping device. This intermediary processes the load factor information and generates the appropriate control signals for the damping actuator, enabling precise variable damping control without requiring direct mechanical coupling or complex mechanical mechanisms.
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 enhances pilot feedback and safety by maintaining load factors within limits, reducing the risk of pitching-up and improving the accuracy and comfort of piloting, while also extending the aircraft's component lifespan and reliability.
Implementation Method 1
a rotary damper with a variable damping coefficient that adjusts based on the instantaneous load factor
Implementation Method 2
providing haptic feedback to the pilot through the manual flight control device
Data Source
AI summary
The present invention relates to haptic feedback for operating at least one manual flight control device (21) for controlling the cyclic pitch of the blades (5) of a rotary wing (4) of a hybrid helicopter (1) via power assistance (27). Said operations of said control device (21) are defined according to a predetermined damping force relationship (A) that is a function of an instantaneous load factor of the hybrid helicopter (1) in such a manner that the instantaneous load factor is maintained between its minimum and maximum limit values in proportion to a position of a thrust control member (20) between its minimum and maximum thrust values (23, 22).