Piezoelectric Thrust Vectoring Flaps for UAV Roll Control
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Solution Overview
Problem
Tailsitter UAVs face challenges in maneuvering near obstacles due to reduced roll maneuverability when propeller ducting is used for efficiency and propeller strike prevention, necessitating enhanced control over thrust direction for both vertical and horizontal movements.
Innovation Solution
Equipping ducted fans with piezoelectric-actuated thrust vectoring flaps that pivot under the control of piezoelectric bimorph actuators to adjust the direction of thrust, allowing for low-energy high-rate maneuvers by controlling the angular position of the flaps to manage roll and pitch.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If propeller ducting is used to prevent propeller strike and improve propulsion efficiency, then safety and efficiency are improved, but roll maneuverability deteriorates due to reduced torque dynamics
Solution Approach 1:
The patent introduces dynamically adjustable thrust vectoring flaps on the ducted fan assembly that can pivot to redirect thrust vectors. This dynamic adjustment capability allows the system to maintain maneuverability by compensating for the reduced torque dynamics of ducted fans, enabling roll control through differential thrust vectoring while preserving the safety benefits of propeller ducting.
2Use of energy by moving object
If propeller ducting is used to improve propulsion efficiency, then energy efficiency is improved, but the ability to perform low-energy high-rate maneuvers deteriorates
Solution Approach 1:
The thrust vectoring flaps enable dynamic redistribution of thrust vectors without requiring high-power actuators. By redirecting existing thrust rather than generating additional force, the system achieves high-rate maneuvers with low energy consumption, maintaining both propulsion efficiency and maneuver productivity.
Solution Approach 2:
The thrust vectoring flaps act as an intermediary mechanism that translates the thrust from the ducted fan into controllable directional forces. This intermediary allows the system to achieve rapid maneuvers by redirecting thrust vectors rather than directly manipulating propeller torque, thereby maintaining propulsion efficiency while improving maneuver capability.
3Ease of operation
If thrust vectoring flaps with piezoelectric actuators are added to ducted fans, then maneuverability is improved, but device complexity increases
Solution Approach 1:
The patent replaces traditional mechanical actuation systems with piezoelectric actuators that directly convert electrical signals into precise angular positioning of the thrust vectoring flaps. This substitution eliminates complex mechanical linkages, gears, and motors, reducing overall device complexity while achieving precise thrust direction control through the piezoelectric effect.
Solution Approach 2:
The piezoelectric actuators enable precise control of flap angular position by changing electrical parameters (voltage) rather than mechanical parameters. This parameter change approach allows for fine-grained control of thrust vectoring with minimal mechanical complexity, as the piezoelectric material directly translates electrical signals into precise angular adjustments.
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 enhances the maneuverability of UAVs by enabling precise control over thrust direction, allowing for safe navigation near obstacles and improved roll and pitch control, addressing the limitations of ducted fan systems.
Implementation Method 1
a piezoelectric actuator operatively coupled to the flap and configured to drive movement of the flap by flexing in response to receipt of electric power
Implementation Method 2
A bimorph is a cantilevered beam or plate used for actuation which consists of two piezoelectrically active layers. It can also have a passive layer between the two active layers. In actuator applications, one active layer contracts and the other expands when a sufficient voltage is applied, thereby causing the piezoelectric bimorph actuator to bend.
Data Source
AI summary
A ducted-fan unmanned aerial vehicle (UAV) capable of low-energy high-rate maneuvers for both vertical roll control and horizontal pitch control. The UAV includes ducted fans which are with respective piezoelectric-actuated thrust vectoring flaps. Thrust vector control is achieved by controlling the angular positions of a plurality of thrust vector flaps pivotably coupled at respective outlets of a plurality of ducts having fan rotors at the inlets. Each thrust vectoring flap has only one degree of freedom in the frame of reference of the UAV, namely, rotation about a single axis that is perpendicular to the axis of the duct. The angular position of the flap is controlled by sending electrical signals to a piezoelectric actuator (e.g., a piezoelectric bimorph actuator) having a voltage sufficient to cause the piezoelectric actuator to bend.