VTOL Aircraft Variable Center of Gravity Transition
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Solution Overview
Problem
Unmanned aircraft systems (UAS) face challenges in maintaining stable flight characteristics during transitions between powered-lift and winged-flight configurations due to differing center of gravity requirements, and existing systems lack efficient mechanisms for in-flight conversion and failure detection.
Innovation Solution
A variable-configuration UAS with pivotable wing assemblies and nacelles that adjust rotor pitch speeds and wing positions to shift the center of gravity, enabling seamless transition between VTOL and winged-flight configurations, and incorporating onboard attitude sensors for failure detection and recovery procedures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the UAS maintains a fixed center of gravity position, then the structure is simpler and easier to manufacture, but the aircraft cannot maintain stable flight characteristics during transitions between powered-lift and winged-flight configurations
Solution Approach 1:
The patent applies the dynamics principle by making the center of gravity position variable rather than fixed. The control system dynamically adjusts the center of gravity location by redistributing mass or adjusting counterweights in response to different flight configurations (powered-lift vs. winged-flight), enabling the aircraft to maintain optimal stability characteristics for each mode without requiring a completely different airframe design.
Solution Approach 2:
The patent implements parameter changes by modifying the center of gravity position parameter based on the desired flight configuration. The system changes the CG location parameter from a fixed value to a variable that can be adjusted to optimal positions for different flight modes, allowing the same aircraft to perform both vertical take-off/landing and conventional winged flight effectively.
2Reliability
If the UAS uses pivotable wing assemblies and adjustable rotor positions to shift center of gravity, then stable flight transitions between configurations are achieved, but the device complexity increases
Solution Approach 1:
The patent applies universality by designing the wing assemblies and rotor mounts to serve multiple functions. The same pivotable wing assemblies and adjustable rotor positions that shift the center of gravity also provide the necessary geometric configuration changes for transitioning between powered-lift and winged-flight modes. This multi-functionality reduces the need for separate dedicated mechanisms for each function.
Solution Approach 2:
The patent merges the center of gravity adjustment function with the configuration transition mechanism. Instead of having separate systems for CG adjustment and configuration change, the patent combines these functions so that the same mechanical movements (wing pivoting, rotor position adjustment) accomplish both the geometric reconfiguration and the center of gravity relocation simultaneously.
3Reliability
If the UAS incorporates onboard attitude sensors for failure detection, then flight safety and reliability are improved, but the device complexity and cost increase
Solution Approach 1:
The patent implements feedback by using onboard attitude sensors to continuously monitor the aircraft's orientation and configuration state. The control system receives feedback from these sensors about the actual attitude and compares it to the expected attitude for the current configuration, enabling automatic detection of anomalies or failures. This feedback loop allows the system to identify problems early and initiate appropriate recovery procedures.
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
Enables stable and efficient flight transitions with enhanced control authority and minimal space requirements for take-off and landing, while ensuring safe recovery in case of component failures.
Implementation Method 1
Each nacelle terminates in a rotor including circumferentially spaced propeller blades which rotate to provide lift and/or thrust
Implementation Method 2
Onboard attitude sensors may monitor the rotational orientation of the UAS
Data Source
AI summary
An unmanned aircraft system (UAS) configured for both vertical take-off and landing (VTOL) and fixed-wing flight operations includes forward and aft wing assemblies mounted to the fuselage, each wing assembly including port and starboard nacelles terminating in motor-driven rotors powered by an onboard control system capable of adjusting rotor speeds. The UAS may transition between a powered-lift VTOL configuration to a winged-flight configuration by shifting its center of gravity forward, pivoting the wing assemblies from a powered-lift position perpendicular to the fuselage to a winged-flight position parallel to the fuselage. The forward rotor blades may be folded back so that the aft rotors may provide primary thrust for winged flight operations. Onboard attitude sensors may detect rotor or control failures, to which the control system responds by triggering a conversion to the winged-flight configuration for recovery operations.