Plasma Actuator Waveform Control for Fast Aircraft Airflow Switching

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Solution Overview

Problem

Plasma actuators used for airflow control on aircraft wings face challenges in quickly switching off the induced airflow and changing flow states due to hysteresis effects, leading to response delays and difficulties in controlling airflow states.

Innovation Solution

A flow control apparatus and method utilizing a plasma actuator with a control system that adjusts the AC voltage waveform by storing and referencing changing conditions to quickly switch between airflow states, including using burst and continuous waveforms to manage airflow states and reduce hysteresis effects.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a plasma actuator is used to control airflow on aircraft wings, then airflow control capability is improved, but response delay occurs due to hysteresis effects

Engineering Contradiction:

Improveairflow control capabilityVSAvoidresponse delay

Core Design Contradiction:

Adaptability or versatilityVSLoss of time

Solution Approach 1:

The patent applies periodic action by using alternating current (AC) voltage with specific waveforms (sine wave, square wave, triangular wave) to drive the plasma actuator. The AC voltage periodically switches the plasma discharge on and off, creating periodic induced flow that can be tuned by adjusting frequency and waveform parameters. This periodic driving mechanism enables rapid switching between different airflow states, overcoming the hysteresis-induced response delay while maintaining effective airflow control capability.

Inventive Principle:

Principle #19Periodic action

2Speed

If AC voltage waveform is adjusted to quickly switch airflow states, then response speed is improved, but control complexity increases

Engineering Contradiction:

Improveresponse speedVSAvoidcontrol complexity

Core Design Contradiction:

SpeedVSDevice complexity

Solution Approach 1:

The patent implements parameter changes by systematically varying AC voltage parameters including waveform type (sine, square, triangular), frequency, and amplitude to achieve different airflow control states. The control system adjusts these electrical parameters to rapidly switch between airflow states without requiring complex mechanical modifications. This approach achieves fast response speed while keeping the control system relatively simple by leveraging the direct relationship between electrical parameters and plasma actuator performance.

Inventive Principle:

Principle #35Parameter changes

3Device complexity

If plasma actuator is used instead of moving control surfaces, then device simplicity is improved, but difficulty in quickly switching off induced airflow occurs

Engineering Contradiction:

Improvedevice simplicityVSAvoiddifficulty in switching off airflow

Core Design Contradiction:

Device complexityVSEase of operation

Solution Approach 1:

The patent replaces traditional mechanical control surfaces (ailerons, flaps) with a plasma actuator driven by AC voltage. This substitution eliminates mechanical linkages, moving parts, and complex actuation mechanisms, achieving device simplicity. The AC voltage waveform control provides direct and rapid switching capability - simply changing the electrical signal immediately affects the plasma discharge and induced flow, making the system easier to operate despite the initial concern about switching off airflow.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

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 rapid switching and control of airflow states, reducing response delays and allowing for efficient suppression or reduction of delamination, adjustment of aerodynamic lift, and angle of attack, effectively utilizing plasma actuators for various airflow control purposes.

Implementation Method 1

The plasma actuator is configured to cause discharge in a discharge area by applying an alternating-current (AC) voltage between electrodes to form an induced flow of gas

Methodology Applied

Scientific EffectPlasma discharge: Plasma

Implementation Method 2

DBD-PA, which uses a dielectric barrier discharge (DBD) to create air flow, is practical as a plasma actuator attached to an aircraft wing

Methodology Applied

Scientific EffectDielectric barrier discharge:

Implementation Method 3

DBD-PA is a plasma actuator in which electrodes are arranged across a dielectric, and plasma is generated only on one side of the dielectric by applying a high alternating-current (AC) voltage between the electrodes

Methodology Applied

Scientific EffectDielectric: Dielectric

Data Source

PatentUS11174007B2Flow control apparatus, flow control method, and aircraft

Publication Date: 2021.11.16 SUBARU CORP

AI summary

A flow control apparatus includes a plasma actuator, a storage device, and a control circuit. The plasma actuator causes discharge in a discharge area by applying an alternating-current (AC) voltage between electrodes to form an induced flow of gas. The electrodes are shifted relatively to each other with a dielectric disposed between them. The storage device stores a changing condition of an AC voltage waveform for changing a gas flow state formed in a flow control area of gas from a first state to a second state by adding the induced flow of gas. The control circuit refers to the changing condition of the AC voltage waveform and control the AC voltage waveform based on the changing condition of the AC voltage waveform, in a case of changing the gas flow state formed in the gas flow control area from the first flow state to the second flow state.