eVTOL Wing Tilt Control Using Differential Motor Torque
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Solution Overview
Problem
Existing VTOL aircraft face challenges such as high weight and energy intensity due to redundant actuation systems and limited operational surfaces, restricting their usability and payload capacity, especially in military and remote applications.
Innovation Solution
The design features angularly offset electric motors with variable pitch propellers and a control system that adjusts rotational speeds to generate turning moments for wing tilt, eliminating the need for large actuators and enabling operation on various surfaces by using brushless DC motors and electronic speed controllers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If traditional actuators and bearings are used to control wing inclination, then the wing tilt function is achieved, but the aircraft weight increases significantly
Solution Approach 1:
The patent extracts the wing tilt control function from traditional heavy actuators and bearings, and implements it through a distributed electric motor system. Each motor unit independently controls the inclination of individual propeller assemblies, eliminating the need for a single complex actuation system and significantly reducing overall weight.
Solution Approach 2:
The wing tilt control system is segmented into multiple independent motor units, each responsible for controlling specific propeller assemblies. This segmentation allows for distributed control without requiring a single heavy actuator system, and enables redundant control capability across multiple units.
2Reliability
If redundant actuation systems are implemented, then system reliability improves, but device complexity and weight increase
Solution Approach 1:
Each electric motor unit serves multiple functions: it provides thrust for flight, controls wing inclination, and acts as a redundant backup for other motor units. This multi-functionality achieves system reliability without requiring separate dedicated redundant actuation systems, thereby avoiding increased complexity.
Solution Approach 2:
The distributed motor system provides self-service redundancy where any motor unit can compensate for the failure of another. The system automatically redistributes control functions among remaining operational units, maintaining reliability without complex monitoring and switching systems.
3Power
If encased fans are used for take-off and landing, then thrust generation is effective, but operational surfaces are limited to hardstand surfaces
Solution Approach 1:
The propeller assemblies are designed with dynamic tilt capability, allowing them to adjust their inclination angle relative to the wing. This dynamic adjustment enables the aircraft to optimize thrust vectoring for different operational surfaces, transitioning from vertical thrust for hardstand operations to angled thrust for unprepared surfaces.
Solution Approach 2:
The system changes the operational parameters of the propellers by adjusting their tilt angles and rotational speeds based on the detected surface type. For unprepared surfaces, the propellers operate at reduced speeds and optimized angles to prevent ground effect interference and ensure safe operations.
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
This solution reduces weight, increases system reliability, and allows VTOL aircraft to operate on non-hardstand surfaces, enhancing payload capacity and flight range while maintaining stability and redundancy.
Implementation Method 1
brushless DC motors
Implementation Method 2
variable pitch propellers
Implementation Method 3
generate turning moments for wing tilt
Data Source
Figure 1~2
Figure 3~4
Figure 5~6
AI summary
A vertical take-off and landing (VTOL) aircraft (10) includes a fuselage and first and second forward wings (20, 22), each wing (20, 22) having a fixed leading edge and a trailing control surface (50) which is pivotal about a generally horizontal pivot axis. The aircraft (10) includes first and second electric motors (60) each having rotors (70), the electric rotors (70) being pivotal with the trailing control surface (50) between a first position in which each rotor (70) has a generally vertical axis of rotation, and a second position in which each rotor (70) has a generally horizontal axis of rotation, a control system (90) is configured to selectively operate the first electric motor (60) and the second electric motor (60) at different rotational speeds to generate a turning moment to pivot the control surface (50) about the pivot axis (33).