Umberto Saetti

Umberto Saetti
University of Maryland

PhD

About

33
Publications
14,582
Reads
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102
Citations
Introduction
Dr. Saetti's research focuses on modeling, simulation, order reduction, and control of high-order models of the coupled flight dynamics, aerodynamics, and aeroacoustics of aircraft, rotorcraft, and biologically-inspired flying vehicles. These models are used for studies involving immersive simulations that make use of Extended Reality (XR), human-machine interaction, synthesis of advanced flight control laws, anddevelopment of innovative pilot cueing methods.
Additional affiliations
August 2019 - present
Georgia Institute of Technology
Position
  • PostDoc Position
January 2015 - August 2019
Pennsylvania State University
Position
  • Research Assistant
Education
May 2017 - May 2019
Pennsylvania State University
Field of study
  • Electrical Engineering
August 2016 - May 2019
Pennsylvania State University
Field of study
  • Aerospace Engineering
August 2014 - May 2016
Pennsylvania State University
Field of study
  • Aerospace Engineering

Publications

Publications (33)
Thesis
Full-text available
This study presents the integration of a flight simulation code (PSUHeloSim), a high fidelity rotor aeromechanics model with free wake (CHARM Rotor Module), and an industry standard noise prediction tool (PSU-WOPWOP) into a comprehensive noise prediction system. The flight simulation uses a Dynamic Inversion autonomous controller to follow a prescr...
Conference Paper
Full-text available
This paper demonstrates the extension of the harmonic decomposition methodology, originally developed for rotorcraft applications, to the study of periodically-forced fluid flows. Starting from a dynamic systems approach to fluid flows, application of the harmonic decomposition method is demonstrated through two examples involving an oscillating cy...
Conference Paper
Full-text available
This paper describes the implementation and linearization of a free-vortex wake model in state-variable form and its use in the prediction of complex aerodynamic interactions during shipboard launch and recovery operations. Following a detailed mathematical description, the wake model is implemented for a UH-60 rotor and tested in different flight...
Conference Paper
Full-text available
This paper describes the extension of a free-vortex wake method in state-variable form originally developed for rotary-wing applications to flapping-wing flight. Following a detailed mathematical description, the wake model is implemented for a hovering insect representative of a hawk moth. A periodic solution to the wake model is found at hover us...
Conference Paper
Full-text available
This paper describes the implementation and linearization of a free-vortex wake model in state-variable form as applied to a helicopter rotor. Following a detailed mathematical description, the wake model is implemented for a UH-60 rotor and tested in forward flight and for simple control inputs. A periodic solution to the wake model is found by ti...
Article
The objective of this investigation is threefold. First, to assess the flight dynamics of an electric vertical take-off and landing (eVTOL) concept aircraft with a propeller-driven rotor. Second, to develop an automatic flight control system (AFCS) for this concept aircraft. Third, to verify the potential safety benefits of the concept aircraft by...
Article
This paper demonstrates the extension of the harmonic decomposition methodology, originally developed for rotorcraft applications, to the study of the nonlinear time-periodic dynamics of flapping-wing flight. A harmonic balance algorithm based on harmonic decomposition is applied to find the periodic equilibrium and approximate linear time-invarian...
Conference Paper
Full-text available
This paper presents a first step in the extension of subspace identification toward the direct identification of harmonic decomposition linear time-invariant (LTI) models from nonlinear time-periodic (NLTP) system responses. The proposed methodology is demonstrated through examples involving the NLTP dynamics of a flapping-wing micro aerial vehicle...
Conference Paper
Full-text available
A novel trajectory generation and control architecture for fully autonomous autorotative flare is proposed that combines rapid path generation with model-based control. The trajectory generation component uses optical Tau theory to compute flare trajectories for both longitudinal and vertical vertical speed. These flare trajectories are tracked by...
Conference Paper
Full-text available
The objective of this paper is to demonstrate the use of the Julia language for developing complex flight simulation models and performing flight control design. Three simulation models are developed: a simple helicopter model (J-SimpleHel), a higher-fidelity helicopter model (J-GenHel), and a fighter jet model (J-F16). These models are validated a...
Article
The objective of this paper is to summarize the relevant published research studies on the extraction of linear time-periodic (LTP) systems and their higher order linear time-invariant (LTI) reformulations from rotorcraft physics-based models and on the identification of LTP systems from rotorcraft experimental data. The paper begins with an introd...
Article
This paper describes a novel approach to regime recognition based on the notion of motion primitives. Originally developed for path planning, motion primitives decompose a vehicle trajectory into maneuver and trim segments. In a regime recognition context, this decomposition can be used to improve component life tracking through separate classifica...
Article
Condition-based maintenance programs for modern helicopters rely on algorithmic techniques to estimate the useful life remaining for life-limited components. Regime-recognition-based condition-based maintenance programs involve a regime recognition step and a damage estimation step in which damage is calculated based on the identified regimes. Rece...
Conference Paper
Full-text available
The paper discusses the development of a novel linearization algorithm to obtain high-order linear time-invariant (LTI) models of the coupled rotorcraft flight dynamics, vibrations, and acoustics. To demonstrate the methodology, the study makes use a nonlinear simulation model of a generic utility helicopter (PSU-HeloSim) that is coupled with an ae...
Conference Paper
Full-text available
This paper demonstrates the extension of the harmonic decomposition methodology, originally developed for rotor-craft applications, to the study of the nonlinear time-periodic dynamics of flapping-wing flight. A harmonic balance algorithm based on harmonic decomposition is successfully applied to find the periodic equilibrium and approximate linear...
Conference Paper
This paper addresses the use of dynamic inversion with direct load feedback to provide combined load alleviation and flight control of rotorocraft. The method is applied to a compound utility rotorcraft with similar airframe properties as a UH-60A along with a lifting wing. The controller makes use of flaperons and horizontal stabilizer in addition...
Article
In this paper, a numerical method is proposed for determining the periodic state and control solutions of nonlinear time-periodic systems. Starting from an initial guess at the solution, the algorithm uses a harmonic balance technique to refine the solution through a gradient-based optimization approach. The algorithm introduces three major innovat...
Conference Paper
Full-text available
An alternative approach to regime recognition that is based on the notion of motion primitives is developed. The algorithm developed is non-causal and leverages the ideas of maneuvers and trims as defined in a motion primitive context. The algorithm functions in three major steps. Given a state and control input time history obtained from flight da...
Conference Paper
Full-text available
The objective of this investigation is three-fold. First, to assess the flight dynamics of an electric Vertical Take-Off and Landing (eVTOL) concept aircraft with a propeller-driven rotor. Second, to develop a Stability and Control Augmentation System (SCAS) for this concept aircraft. Third, to verify the potential safety benefits of the concept ai...
Conference Paper
Full-text available
Modern flight vehicle development typically involves significant uncertainty in aerodynamic loads and vehicle control responses. In many cases, it may be necessary to consider this uncertainty in preliminary evaluations of stability, handling qualities (HQ), and performance. This paper introduces a novel methodology for computing these quantities i...
Article
The objective of this research effort is to assess the impact of load alleviation control on the quantitative handling qualities specifications (also known as predicted handling qualities) of both conventional helicopters and compound rotorcraft in forward flight. First, an overview on how the harmonic decomposition methodology is used toward load...
Article
The objectives of this paper are to advance dynamic inversion (DI) and explicit model following (EMF) flight control laws for quadrotor unmanned aerial systems (UAS) and to develop an efficient strategy to compute the stability and performance robustness statistics of such control laws given parametric model uncertainty. For this purpose, a paramet...
Article
The present study considers two notional rotorcraft models: a conventional utility helicopter, representative of an H-60, and a wing-only compound utility rotorcraft, representative of an H-60 with a wing similar to the X-49A wing. An explicit model following (EMF) control scheme is designed to achieve stability and desired rate command / attitude...
Conference Paper
Full-text available
This paper proposes a novel mathematical methodology for probabilistic handling qualities evaluation using the Koopman operator. The Koopman operator is used to quantify the impact of parametric uncertainty in a pilot model to specific pilot-vehicle system performance specifications and to perceived vehicle handling qualities. The considered specif...
Thesis
Full-text available
The objective of this research effort is to develop rotorcraft flight control laws that minimize unsteady rotor loads by acting solely through the primary flight controls (first harmonic swashplate control). As opposed to Higher-Harmonic Control, this strategy does not affect stationary (periodic trim) loads, and is therefore effective only in mane...
Conference Paper
Full-text available
The objective of the paper is to study the F-Helix eVTOL concept. This concept modifies the SH-4 Silvercraft light helicopter to use electric propulsion and a tip driven rotor. It is intended to compete with rotorcraft in the lightweight class and address future urban air mobility needs. The elimination of shaft driven propulsion is intended to red...
Conference Paper
Full-text available
The objective of this paper is to develop helicopter flight control laws that minimize unsteady rotor loads while meeting desired handling qualities. These control laws are meant to act solely through the primary flight controls. First, an overview on how the harmonic decomposition methodology is used towards load alleviation control is presented....
Conference Paper
Full-text available
A quadrotor was assembled with commercial off-the-shelf (COTS) components readily available on the market as a platform for future research at Penn State. As a first step in this research, a model of the quadrotor is identified from flight data. Given the largely decoupled dynamics at low speed, frequency sweeps in different channels are performed...
Conference Paper
Full-text available
The present study considers two notional rotorcraft models: a conventional utility helicopter, representative of an H-60, and a wing-only compound utility rotorcraft, representative of an H-60 with with a wing similar to the X-49A wing. An Explicit Model Following (EMF) control scheme is designed to achieve stability and desired Rate Command / Atti...
Conference Paper
Full-text available
An Explicit Model Following (EMF) control scheme is designed to achieve stability and desired Rate Command / Attitude Hold (RCAH) response around the roll, pitch and yaw axes, while alleviating vibratory loads through both feed-forward and feedback compensation. First, the effect of command model tailoring is explored to understand the effect of fe...
Conference Paper
Full-text available
This study presents the integration of a flight simulation code (PSUHeloSim), a high fidelity rotor aeromechanics model with free wake (CHARM Rotor Module), and an industry standard noise prediction tool (PSU-WOPWOP) into a comprehensive noise prediction system. The flight simulation uses an autonomous controller to follow a prescribed trajectory f...
Conference Paper
Full-text available
This paper is focused on gaining a deeper understanding on how different flight procedures relate to noise generation and how helicopter rotor noise may be abated. The paper describes a noise prediction system composed of a flight simulation model, a rotor airloads and airwake model, and a rotor noise prediction code which can be used to predict th...

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