Passive Gust Load Alleviation via Counterweighted Control Surface
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Solution Overview
Problem
Aircraft and other vehicles experience adverse effects from transient or sustained wind gusts, which impose gust loads on aerodynamic panels, affecting ride quality and structural loads, and existing solutions rely on sensor-based active load detection and actuation, leading to signal latency and time lag.
Innovation Solution
Passive gust load alleviation devices using a free-floating counterweighted aerodynamic control surface connected via a revolute joint, which deflects to oppose gust loads without active sensor detection, combined with a controllable servo tab for selective position control and optional actuator for active modal suppression.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If sensor-based active load detection and actuator-based load reduction systems are used, then gust load alleviation can be achieved, but signal latency and time lag occur between gust onset and control response
Solution Approach 1:
The control surface is designed to automatically respond to gust loads through its own aerodynamic forces and counterweight mechanism, without requiring external sensors or actuators. The system serves itself by using the gust-induced motion to trigger the counterweight, which then generates the opposing aerodynamic force to alleviate the load.
Solution Approach 2:
A counterweight is introduced as an intermediary element between the gust load and the control surface. The counterweight translates the gust-induced control surface motion into an opposing aerodynamic force, acting as a mediator that eliminates the need for electronic sensors and actuators while providing instantaneous response.
2Reliability
If sensor-based active control systems are implemented, then gust load detection is possible, but system complexity increases due to additional hardware and control algorithms
Solution Approach 1:
The complex electronic control system (sensors, processors, actuators) is extracted and removed from the design. Instead, a purely passive mechanical-aerodynamic system is used where the counterweight and control surface geometry alone provide the gust load detection and response functions without any electronic components.
Solution Approach 2:
The system detects and responds to gust loads through inherent aerodynamic and gravitational forces acting on the control surface and counterweight, eliminating the need for external detection and control systems. The physics of the system itself provides the sensing and actuation functions.
3Speed
If free-floating counterweighted control surfaces are used, then instantaneous gust load response is achieved, but operator control capability may be reduced
Solution Approach 1:
The control surface is designed with dynamic characteristics that allow it to be free-floating and responsive to gusts during normal flight, but capable of being constrained or held in position when operator input is applied. The system transitions between passive and active control modes as needed.
Solution Approach 2:
A servo tab or similar intermediary mechanism is used to translate operator control inputs into control surface deflections. The servo tab acts as a mediator that allows the operator to maintain control authority while the main control surface remains free to respond passively to gusts.
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
Quickly and effectively reduces gust loads without latency, maintaining aerodynamic control and improving ride quality by instantly deflecting in response to wind gusts, while simplifying system complexity and eliminating the need for active control systems.
Implementation Method 1
A counterweight is operatively connected to the control surface and has a center of gravity (COG) located forward of an axis of rotation of the revolute joint. This configuration and forward placement enables the control surface to passively deflect about the axis of rotation to instantly alleviate transient or sustained gust loads
Implementation Method 2
An aerodynamic control surface that is integrated with or mounted to the aerodynamic panel deflects in response to an impulsive wind gust, and does so to an angular degree that is sufficient for aerodynamically opposing resulting structural motion of the aerodynamic panel
Data Source
AI summary
A passive gust load alleviation device for an aerodynamic panel includes a free-floating aerodynamic control surface connected to the panel via a revolute joint. A counterweight is connected to the control surface. Relative to a direction of ambient airflow, the counterweight has a center of gravity forward of the axis of rotation. The counterweight is configured to passively deflect the control surface about the axis to alleviate a gust load. A vehicle includes an aerodynamic panel connected to a body and extending into ambient airflow, and the control surface and counterweight. A method for alleviating the gust load on an aircraft panel includes connecting the control panel, via the revolute joint, along a trailing edge of the panel, and during a flight of an aircraft having the panel, passively deflecting the control panel about the axis in response to an incident wind gust.