Tonal Noise Prediction of a Distributed Propulsion Unmanned Aerial Vehicle

Pascioni, Kyle A.; Rizzi, Stephen A.

doi:10.2514/6.2018-2951

Cited by 24 publications

(4 citation statements)

References 14 publications

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“…This initial work uses total radiated sound power level, or sound generated by the source, as the acoustic constraint. Although total sound power is not likely to be the constraint ultimately used in future work, its computation is simple and it avoided the complications of estimating sound pressure level at distant observers, as discussed by Pascioni and Rizzi [9].…”

Section: Source Noise Modelmentioning

confidence: 99%

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Feedback Control of Flight Speed to Reduce Unmanned Aerial System Noise

Galles

Schiller

Ackerman

et al. 2018

2018 AIAA/CEAS Aeroacoustics Conference

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The aim of this initial study was to incorporate an acoustic metric into the flight control system of an unmanned aerial vehicle. This could be used to mitigate the noise impact of unmanned aerial systems operating near residential communities. To incorporate an acoustic metric into a flight control system, two things were required: a source noise model, and an acoustic controller. An acoustic model was developed based on Gutin's work to estimate propeller noise. The flight control system was augmented with a controller to reduce propeller noise using feedback control of the commanded flight speed until an acoustic target was met. This control approach focused on modifying flight speed only, with no perturbation to the trajectory. Multiple flight simulations were performed and the results show that integrating an acoustic metric into the flight control system of an unmanned aerial system is possible. Nomenclature c = Speed of sound in air (m/s) ì c(t) = Roll and pitch rates from the path following controller, flight dynamics controller input E = Total energy used (J) e a (t) = Acoustic error (dB re. 10 −12 W) J qn (x) = qn th order Bessel function of the first kind, of the argument x Kv = Motor constant (r pm/V) K p = Proportional gain, tuning parameter (m/s · dB −1 ) K i = Integral gain, tuning parameter (m/s 2 · dB −1 ) K b = Saturation error gain, tuning parameter (s −1 ) k = qω 1 /c, acoustic wave number L W = Total radiated sound power level (dB re. 10 −12 W) M max = Maximum value allowed for u sat (t) (m/s) M min = Minimum value allowed for u sat (t) (m/s) n = Number of propeller blades p r ms = Sound pressure (RMS) at a specified distance, r, and angle, ϑ, from the center of propeller rotation (Pa) P m = Electrical motor power (W) Q = Motor torque (N · m) q = Harmonic index R = Radius of propeller blade (m) r = Distance from center of propeller rotation (m) r(t) = Acoustic target, reference sound power level (dB re. 10 −12 W) ì s d (t) = [x (t) , y (t) , z (t)], time-varying desired point, path following controller input (m) r a (t) = Filtered reference (dB re. 10 −12 W) T = Thrust produced by propeller (N) u(t) = Unsaturated velocity command in the acoustic controller (m/s) u sat (t) = Saturated velocity command in the acoustic controller (m/s) ì u(t) = Flight dynamics controller output vector, plant model input v n (t) = Nominal velocity command, defined by mission requirements (m/s) ∆v a (t) = Change in velocity command based on acoustic error (m/s) v c (t) = Velocity command modified by acoustic controller, path following controller input (m/s) W = Sound power of propellers (W) W 0 = 10 −12 W, reference sound power x = k R sin ϑ, Bessel function argument y a (t) = Source noise estimate, output from acoustic model (dB re. 10 −12 W) ì y(t) = Flight properties vector, system output ϑ = Angle from propeller rotation axis (rad) ρ = Density of air (kg/m 3 ) θ = Motor angular velocity (r pm) Ω = Angular velocity of propeller (rad/s) ω 1 = nΩ, Blade passage frequency (rad/s)

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Section: Source Noise Modelmentioning

confidence: 99%

“…L W, T ot al = 10 log 10 W T ot al W 0 (9) in which L W is the total radiated sound power level and W 0 is the reference power, 10 −12 W.…”

Section: B Implementationmentioning

confidence: 99%

Feedback Control of Flight Speed to Reduce Unmanned Aerial System Noise

Galles

Schiller

Ackerman

et al. 2018

2018 AIAA/CEAS Aeroacoustics Conference

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“…Noise emissions of those eVTOL aircraft are mainly produced by the propulsion and lifting units and are of major concern during certification. During vertical flight operation, usually performed in urban and rural areas, the propulsion units' thrust generates lift forces [3,4] and, simultaneously, a substantial amount of noise emissions. One type of an electric propulsion system is an EDF.…”

Section: Introductionmentioning

confidence: 99%

An Affordable Acoustic Measurement Campaign for Early Prototyping Applied to Electric Ducted Fan Units

Schoder

Schmidt

Fürlinger³

et al. 2023

Fluids

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New innovative green concepts in electrified vertical take-off and landing vehicles are currently emerging as a revolution in urban mobility going into the third dimension (vertically). The high population density of cities makes the market share highly attractive while posing an extraordinary challenge in terms of community acceptance due to the increasing and possibly noisier commuter traffic. In addition to passenger transport, package deliveries to customers by drones may enter the market. The new challenges associated with this increasing transportation need in urban, rural, and populated areas pose challenges for established companies and startups to deliver low-noise emission products. The article’s objective is to revisit the benefits and drawbacks of an affordable acoustic measurement campaign focused on early prototyping. In the very early phase of product development, available resources are often considerably limited. With this in mind, this article discusses the sound power results using the enveloping surface method in a typically available low-reflection room with a reflecting floor according to DIN EN ISO 3744:2011-02. The method is applied to a subsonic electric ducted fan (EDF) unit of a 1:2 scaled electrified vertical take-off and landing vehicle. The results show that considerable information at low costs can be gained for the early prototyping stage, despite this easy-to-use, easy-to-realize, and non-fine-tuned measurement setup. Furthermore, the limitations and improvements to a possible experimental setup are presented to discuss a potentially more ideal measurement environment. Measurements at discrete operating points and transient measurements across the total operating range were conducted to provide complete information on the EDF’s acoustic behavior. The rotor-self noise and the rotor–stator interaction were identified as primary tonal sound sources, along with the highest broadband noise sources located on the rotor. Based on engineering experience, a first acoustic improvement treatment was also quantified with a sound power level reduction of 4 dB(A). In conclusion, the presented method is a beneficial first measurement campaign to quantify the acoustic properties of an electric ducted fan unit under minimal resources in a reasonable time of several weeks when starting from scratch.

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“…Electric and hybrid DEP solutions have become an increasingly attractive option for the aviation industry [1], and have been thoroughly studied in terms of aerodynamics, emissions and costs [2][3][4][5], but more scarcely investigated in terms of noise emissions. Previous efforts were mostly focused on the NASA X-57 [6,7], or NASA GL-10 project [8,9]. Several studies [6,[10][11][12] indicate that DEP architectures offer promising perspectives for noise reduction and appear as a viable solution for delivering the strict mid-to-long term environmental goals set by governmental agencies.…”

Section: Introductionmentioning

confidence: 99%

Measurement and modelling of aero-acoustic installation effects in tractor and pusher propeller architectures

Drofelnik

Andrejašič

Mocan

et al. 2021

Aiaa Aviation 2021 Forum

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HAL is a multi-disciplinary open access archive for the deposit and dissemination of scientific research documents, whether they are published or not. The documents may come from teaching and research institutions in France or abroad, or from public or private research centers. L'archive ouverte pluridisciplinaire HAL, est destinée au dépôt et à la diffusion de documents scientifiques de niveau recherche, publiés ou non, émanant des établissements d'enseignement et de recherche français ou étrangers, des laboratoires publics ou privés.

show abstract

Tonal Noise Prediction of a Distributed Propulsion Unmanned Aerial Vehicle

Cited by 24 publications

References 14 publications

Feedback Control of Flight Speed to Reduce Unmanned Aerial System Noise

Feedback Control of Flight Speed to Reduce Unmanned Aerial System Noise

An Affordable Acoustic Measurement Campaign for Early Prototyping Applied to Electric Ducted Fan Units

Measurement and modelling of aero-acoustic installation effects in tractor and pusher propeller architectures

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