Rotorcraft Control Member Travel Reduction via Dynamic Law Switching
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional rotorcraft control systems require large travel distances for control members, leading to ergonomic challenges and discomfort in the cockpit, as they lack the ability to use control members with small travel while maintaining full rotor control range and sensitivity.
Innovation Solution
A control system with selector means to define two disjoint position ranges for the control member, allowing distinct control laws to be applied, one linear in position and the other linear in speed, to reduce travel distance while maintaining control range and sensitivity, and including monitor means to activate these laws based on the rotorcraft's landed state.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If conventional control members with large travel are used, then the full rotor control range is covered and good piloting sensitivity is achieved, but the cockpit ergonomics deteriorate and pilot comfort is reduced
Solution Approach 1:
The control system dynamically switches between two control laws based on the rotorcraft's operational state (grounded vs. airborne). When grounded, a first control law with amplified control authority is applied, allowing short travel. When airborne, a second control law takes over to maintain full control range. This dynamic adaptation resolves the contradiction by adjusting control characteristics according to flight phase.
Solution Approach 2:
The system changes the control law parameters based on the rotorcraft state. The selector means switches between a first control law (suitable for grounded operation with short travel) and a second control law (suitable for flight with full range). This parameter change allows the control member to have short travel while still achieving full rotor control authority when needed.
2Length of moving object
If a single proportional control law is used, then the control system is simple, but the control member travel must be very large to cover the full rotor movement range
Solution Approach 1:
The control system uses a selector means that dynamically chooses between two control laws based on rotorcraft state. This dynamic switching allows the system to use short-travel control members while maintaining full control authority through appropriate law selection, avoiding the need for excessively large travel distances.
Solution Approach 2:
The control law is segmented into two distinct laws: a first control law for grounded operation and a second control law for flight operation. Each law is optimized for its specific operational context, allowing short travel to suffice while maintaining full control range through selective application of the appropriate law.
3Length of moving object
If electrical or optical controls with servo-control are used, then the control member can be mechanically decoupled from the rotor, but the control member travel remains very large equivalent to mechanical systems
Solution Approach 1:
The system changes control law parameters based on operational state. The first control law provides amplified control authority for grounded operation, allowing short travel. The second control law maintains full range for flight. This parameter adaptation enables short-travel control members to achieve full rotor control authority.
Solution Approach 2:
The control system dynamically switches between control laws to adapt to flight phase. This dynamic behavior allows the use of short-travel control members while maintaining full control capability through appropriate law selection based on rotorcraft state.
Data Source
AI summary
A control system for controlling a rotorcraft rotor, to a rotorcraft fitted therewith, and to a corresponding control method. The system comprises selector means for defining at least two disjoint position ranges for the control member between two physical abutments corresponding to the movement limits of the control member, a first position range being defined between at least two first limit values about a zero force position of the control member, and at least one second position range being defined between at least one of the at least two first limit values and at least one second limit value; and control means for allocating a first control law to the first position range of the control member and a second control law to the second position range of the control member, the first and second control laws being selected to be mutually distinct.