Flight Attitude Control Prioritization for VTOL-Biplane Transition
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current aircraft transitioning between thrust-borne lift in VTOL orientation and wing-borne lift in biplane orientation face challenges in efficiently controlling flight attitudes, particularly in maintaining hover stability and transitioning between these modes due to downwash inefficiencies and complex control requirements.
Innovation Solution
A method and system that prioritize the use of flight attitude controls by determining optimal flight states, monitoring current states, identifying deviations, and implementing the highest order flight attitude control to bias the aircraft towards the optimal state, utilizing a flight control computing system to manage thrust vectoring, rotor speed, and aerosurface position.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If tiltrotor aircraft use fixed wing for forward flight, then forward airspeed and range are improved, but downwash inefficiencies occur during vertical takeoff and landing due to interference from the fixed wing
Solution Approach 1:
The patent employs dynamic reconfiguration of the propulsion system, where proprotors can rotate between horizontal and vertical planes, and nacelles can tilt relative to the fixed wing. This dynamic adaptability allows the aircraft to optimize performance for different flight phases: horizontal proprotor orientation for forward flight to maintain speed and range, and vertical orientation for takeoff/landing to eliminate downwash interference with the fixed wing.
Solution Approach 2:
The invention introduces a rotational dimension to the proprotors, enabling them to change their plane of rotation from horizontal to vertical. This dimensional change allows the same propulsion element to serve dual functions: generating forward thrust during horizontal flight and providing vertical lift during takeoff and landing, thereby resolving the conflict between forward airspeed and downwash efficiency.
2Loss of energy
If tiltwing aircraft rotate wing to vertical orientation for VTOL, then vertical thrust efficiency is improved, but control during hover becomes more difficult due to large surface area exposed to crosswinds
Solution Approach 1:
The patent segments the control functions by separating the lift-generating function (performed by the vertically oriented proprotors) from the control function (performed by dedicated flight control surfaces and thrust vectoring). This segmentation allows the large vertical surface area to be used purely for thrust generation without compromising hover control, as independent control mechanisms can counteract crosswind effects on the vertical wing.
Solution Approach 2:
The invention introduces intermediary control elements such as flight control computers and thrust vectoring systems that mediate between pilot inputs and the actual control surfaces. These intermediaries process control commands and coordinate multiple control effects to maintain stable hover despite the large surface area exposed to crosswinds, thereby improving ease of operation.
3Adaptability or versatility
If aircraft use multiple flight attitude controls for transition between VTOL and biplane orientation, then adaptability is improved, but device complexity increases
Solution Approach 1:
The patent implements universal control mechanisms where the flight control system and propulsion assemblies serve multiple functions across different flight phases. The same flight control computer manages both VTOL and biplane orientation transitions, and the same propulsion assemblies provide both vertical lift and forward thrust. This multi-functionality reduces the need for separate dedicated control systems for each flight mode, thereby reducing overall device complexity.
Solution Approach 2:
The invention employs dynamic control authority distribution where the relative importance and activation of different control surfaces change automatically based on the current flight phase. During VTOL operations, thrust vectoring and rotor pitch controls have higher authority, while during biplane flight, conventional aerodynamic control surfaces become more prominent. This dynamic reconfiguration of control authority simplifies the control system by automatically adapting to flight conditions rather than requiring manual switching between complex control modes.
Data Source
AI summary
Systems and methods of prioritizing the use of flight attitude controls of aircraft operable to transition between thrust-borne lift in a VTOL orientation and wing-borne lift in a biplane orientation. A method includes determining an optimal flight attitude state for the aircraft during flight, the aircraft including first and second wings with first and second pylons coupled therebetween forming an airframe with a two-dimensional distributed thrust array and a plurality of aerosurfaces coupled to the airframe; monitoring the current flight attitude state of the aircraft; identifying deviations between the current flight attitude state and the optimal flight attitude state; ordering the flight attitude controls of the aircraft based upon the flight attitude control authority of each in the current flight attitude state; and implementing the highest order flight attitude control to bias the aircraft from the current flight attitude state toward the optimal flight attitude state.