Deep Reinforcement Learning Attitude Control of Fixed-Wing UAVs Using Proximal Policy Optimization

Contemporary autopilot systems for unmanned aerial vehicles (UAVs) are far more limited in their flight envelope as compared to experienced human pilots, thereby restricting the conditions UAVs can operate in and the types of missions they can accomplish autonomously. This paper proposes a deep reinforcement learning (DRL) controller to handle the nonlinear attitude control problem, enabling extended flight envelopes for fixed-wing UAVs. A proof-of-concept controller using the proximal policy optimization (PPO) algorithm is developed, and is shown to be capable of stabilizing a fixed-wing UAV from a large set of initial conditions to reference roll, pitch and airspeed values. The training process is outlined and key factors for its progression rate are considered, with the most important factor found to be limiting the number of variables in the observation vector, and including values for several previous time steps for these variables. The trained reinforcement learning (RL) controller is compared to a proportional-integral-derivative (PID) controller, and is found to converge in more cases than the PID controller, with comparable performance. Furthermore, the RL controller is shown to generalize well to unseen disturbances in the form of wind and turbulence, even in severe disturbance conditions.Comment: 11 pages, 3 figures, 2019 International Conference on Unmanned Aircraft Systems (ICUAS

Reimagining the Liberal Arts in an Age of Technoscientific Progress

The following study will investigate the impact of dismantling liberal arts curriculum during an era of dramatic technoscientific progress. I will explore the development of the posthuman focusing specifically on the areas of virtual reality and biomedicine. As I unravel the implications that virtual reality and biomedicine will have on society in the coming decades, I will describe how a new liberal arts curriculum must be entertained by educators in order to maintain innovation, play, and ethical considerations in posthuman developments. In order for our students to become contributing members of a global community, they must be given the opportunity to learn how to think critically through an immersion in a new curriculum that will focus on modern/postmodern art, literature, and film productions. This study will explore how the disciplines of the sciences and those of the liberal arts might coalesce for the betterment of our students and our society

Atrium

Architectural history has overlooked the significance of one of its oldest and most fundamental elements. Present at the origins of architecture and characteristically essential to almost any contemporary design (over two floors), the atrium consistently finds itself in the lapse of history’s judgment - perhaps due to its consistent presence. The atrium has ranged from the hole in primitive shelters for smoke management, to its introduction as a proper space in the Roman domus and finally manifesting itself at its most extravagant in Portman’s hotel designs. However, as the atrium acts as the auspice for all vertical openings in a building, it is at once the space - in the form of the courtyard - that protects primitive tribes from surrounding threats - and elsewhere, the mezzanine, allowing the viewer to see the stage in the theatre for the upper class. But it is this same variability that makes the atrium everywhere and nowhere, causing its most important contribution to architecture and society to go unnoticed. As the central space in the building in which people gather, the atrium is an element of collectivity that has played a core historical role, as a catalyst or antagonist, in the urban development of mankind through social interaction

Conan the transmedial. Identity and metamorphoses in a transmedial character

[Abstract] The goal of our work is to investigate, from a sociosemiotic point of view, the status of character (and serial carachter in particular) in transmedial storytelling and the persistence of his identity through the different medial platforms. In this paper (part of a larger study) we will examine what we consider an examplary case: Conan the Barbarian. Conan is in fact a hero who has a long history of remakes and translations from one medium to another: it was originally created as a literary character by Robert Howard on the page of the pulp magazine «Weird Tales»; after his creator’s death, the life history of Conan w caosmpleted by several tales written by L.S. De Camp and Lin Carter, then the same two writers and several other authors «continued» it in a long series of apocryphal novels. Finally the carachter was translated and replicated by most other media: illustration (from the pulp covers of the'30s to the drawings of Frank Franzetta, who has somehow established his canonical iconography), comics (Marvel Comics, then Dark Storm), movies (2 films, and a third in production) a nadlso — what is less known — television (the TV serial «Conan», and two series of cartoons), computer and role playing games. What is left of the character, in this sequence of translations, remakes and rewritings? Vanished a figurative identity (partially modified over time), and changed, of course, even his narrative attributes; does at least his modal identity (in the sense of Greimasian semiotics) still remain? Paolo Bertetti is professor of Semiotics of audiovisual text at the University of Sienne, and of Philosophy and theory and of languages at the Polytechnic of Turin. He has been secretary and vicepresident of AISS, (Associazione Italiana di Studi Semiotici). He is editorial coordinator of the magazine Carte Semiotiche and Italian correspondent of De Signis, organ of FELSA.m ong his recent books: Semiofood. Comunicazione e cultura del cibo (2006; ed. With Giovanni Manetti and Alessandro Prato), Mediamerica. Semiotica e analisi dei media in America latina (2007; ed. with Carlos Scolari)

Active flow control on cambered airfoils at ultralow Reynolds using synthetic jets

Active flow control methods have been widely studied for more than a decade in order to improve the airfoil's efficiency. This study is focused on fluidic actuation (the addition or subtraction of momentum to/from the boundary layer by blowing and/or sucking fluid). A synthetic jet is a very particular type of fluidic actuation that involves periodic blowing and suction with zero-net-mass-flow over a the full period. Its success as an active flow control device has been extensively reported by several authors. As it can be seen synthetic jet technology provides good results on boundary layer reattachment and therefore, an improvement on the airfoil's efficiency. What is more, is a generic system that can be widespread on multiple types of airfoils such as unmanned aerial vehicles and conventional airplanes airfoils. The effectiveness of control in mitigating boundary separation depends on a number of parameters related both to the flow itself and the control input such as: frequency and amplitude of the excitation, the excitation shape, exit diameter and cavity shape. Since the synthetic jet system has several degrees of freedom and the flux is unpredictable, multiple simulations have to be done in order to assess the best configuration to achieve the maximum airfoil's efficiency. The well-known excitation of the synthetic jet is the zero-net-mass-flow that combines both expulsion and suction periodically. In this study, we also evaluate other types of excitations that imply more or less energy into the system that is characterized with the momentum coefficient. The goal is to assess thoroughly this existent trade-off between the aerodynamics performance and the momentum coefficient. And finally, extract deep conclusions and assess the best synthetic jet configuration where the aerodynamics performances are improved with a low momentum coefficient.. To extract suitably conclusions we pass through a thorough and intricate process that starts with the adapted and generic discretized surface for the synthetic jet that we use to solve the Navier-Stokes equations, then the appropriate conversions to simulate with spectral element framework Nektar++ and finally the detailed extraction of results. Moreover, we adopt to this study a practical approach with an unmanned aerial vehicle (UAV Skywalker x6) airfoil's photogrammetry that we use to simulate

Spartan Daily, February 25, 2000

Volume 114, Issue 21https://scholarworks.sjsu.edu/spartandaily/9518/thumbnail.jp

Reading in the Disciplines: The Challenges of Adolescent Literacy

A companion report to Carnegie's Time to Act, focuses on the specific skills and literacy support needed for reading in academic subject areas in higher grades. Outlines strategies for teaching content knowledge and reading strategies together

Decomposition-based mission planning for fixed-wing UAVs surveying in wind

This paper presents a new method for planning fixed-wing aerial survey paths that ensures efficient image coverage of a large complex agricultural field in the presence of wind. By decomposing any complex polygonal field into multiple convex polygons, the traditional back-and-forth boustrophedon paths can be used to ensure coverage of these decomposed regions. To decompose a complex field in an efficient and fast manner, a top-down recursive greedy approach is used to traverse the search space in order to minimise flight time of the survey. This optimisation can be computed fast enough for use in the field. As wind can severely affect flight time, it is included in the flight time calculation in a systematic way using a verified cost function that offer greatly reduced survey times in wind. Other improved cost functions have been developed to take into account real world problems, e.g. No Fly Zones, in addition to flight time. A number of real surveys are performed in order to show the flight time in wind model is accurate, to make further comparisons to previous techniques and to show that the proposed method works in real-world conditions providing total image coverage. A number of missions are generated and flown for real complex agricultural fields. In addition to this, the wind field around a survey area is measured from a multi-rotor carrying an ultrasonic wind speed sensor. This shows that the assumption of steady uniform wind holds true for the small areas and time scales of a Unmanned Aerial Vehicle (UAV) aerial survey.</div