Autonomous Parafoil Takeoff via Wing Attitude Feedback Control

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Solution Overview

Problem

Flexible-wing aircraft face challenges in automatic take-off due to uncontrolled wing behavior and sensitivity to wind, requiring skilled piloting or remote control, which can lead to malfunctions and failure.

Innovation Solution

Equipping the aircraft with a wing attitude sensor featuring accelerometers and gyroscopes, communicating with an autopilot to control actuators on lines and motor means, enabling precise management of take-off parameters and eliminating the need for human intervention.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the sail is inflated by relative wind during takeoff, then the lift necessary to carry the load is created, but the uncontrolled wing behavior causes swings, collapses, and changes of direction that risk overturning the carriage

Engineering Contradiction:
Improvetakeoff reliabilityVSAvoidwing stability
Core Design Contradiction:
ReliabilityVSStability of the object's composition

Solution Approach 1:

The patent implements a feedback control system where sensors detect the actual position and orientation of the wing during inflation, and the autopilot continuously adjusts actuator commands to correct deviations from the desired takeoff trajectory. This closed-loop control stabilizes the wing behavior during the critical inflation phase, preventing swings and collapses while maintaining reliable takeoff.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The system achieves autonomous takeoff by integrating sensors, autopilot, and actuators that work together without human intervention. The carriage self-regulates its position and the wing self-stabilizes during inflation through automated control algorithms, eliminating the need for pilot skill while ensuring safe takeoff execution.

Inventive Principle:
Principle #25Self-service

2Extent of automation

If remote control is used for takeoff, then the aircraft can be operated without a pilot on board, but the delay and poor anticipation by the remote pilot amplify the rocking phenomenon

Engineering Contradiction:
Improveautomatic operation capabilityVSAvoidcontrol responsiveness
Core Design Contradiction:
Extent of automationVSEase of operation

Solution Approach 1:

The patent replaces remote mechanical control with an integrated onboard autonomous control system. Sensors mounted on the carriage directly measure the actual motion parameters, and the autopilot processes this data in real-time to generate actuator commands, eliminating the time delay and anticipation limitations of remote piloting while maintaining full automation.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

3Ease of manufacture

If the carriage is driven by traction means such as a winch to deploy the sail, then the sail can be hoisted above the carriage, but the system complexity and potential failure points increase

Engineering Contradiction:
Improvetakeoff maneuverabilityVSAvoidtraction system complexity
Core Design Contradiction:
Ease of manufactureVSDevice complexity

Solution Approach 1:

The patent employs a self-service approach where the carriage uses its own propulsion motor to achieve the necessary speed for natural wing inflation, eliminating the need for external winch systems. The motorized carriage accelerates along the runway, generating the relative wind needed to inflate the wing, thereby reducing mechanical complexity while maintaining effective sail deployment.

Inventive Principle:
Principle #25Self-service

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 reliable, automatic, and synchronized take-off without pilot skill, ensuring safe and stable flight initiation, even in challenging conditions, by processing inertial data for precise control of flight surfaces and motorization.

Implementation Method 1

said wing being equipped with at least one wing attitude sensor, comprising at least one accelerometer on at least two axes and at least one gyrometer on at least two axes

Methodology Applied
Scientific EffectAccelerometer: Accelerometer

Implementation Method 2

said wing attitude sensor, comprising at least one accelerometer on at least two axes and at least one gyrometer on at least two axes

Methodology Applied
Scientific EffectGyroscope: Gyroscope

Implementation Method 3

the sail is designed to be inflated by the relative wind which creates the lift necessary to carry a load

Methodology Applied
Scientific EffectLift: Aerofoil

Data Source

PatentEP2521670B1Autonomous take-off method of a parafoil aircraft, air expandable wing and aircraft
Publication Date: 2014.03.19 SWISSAVIA

AI summary

The invention relates to an automatic takeoff method for an aircraft with a flexible airfoil, comprising a carriage suspended by rigging lines from an airfoil. According to said method: - said carriage is provided with an autopilot controlling actuators that control said rigging lines; - said airfoil is provided with an airfoil attitude sensor, comprising a biaxial accelerometer and a biaxial rate gyro, capable of defining the position of an airfoil reference frame in relation to the ground, and means for communicating with said autopilot; - during takeoff, information is received from said airfoil attitude sensor and transmitted to said autopilot for the purpose of controlling said actuators. The invention also relates to an airfoil for the implementation of said method, comprising an airfoil attitude sensor with an inertial unit with a biaxial accelerometer and a biaxial rate gyro, and means for communicating with an autopilot. The invention further relates to an aircraft comprising such an airfoil.