Educational Case Study on H-Infinity Robust Performance Design

This paper deals with the design of a robust controller according to the H-infinity norm of mixed sensitivity functions. The motivation and origin are given by educational reasons. It compares how settings of individual weighting functions affect the quality of control when designing a sub-optimal controller. First, a controller for a system without uncertainty is considered (a nominal system representing a motor with a flexible clutch) and then the design is modified for a perturbated system with uncertainty in gain and also in the time constant

Dual Observer Based Adaptive Controller for Hybrid Drones

A biplane quadrotor (hybrid vehicle) benefits from rotary-wing and fixed-wing structures. We design a dual observer-based autonomous trajectory tracking controller for the biplane quadrotor. Extended state observer (ESO) is designed for the state estimation, and based on this estimation, a Backstepping controller (BSC), Integral Terminal Sliding Mode Controller (ITSMC), and Hybrid Controller (HC) that is a combination of ITSMC + BSC are designed for the trajectory tracking. Further, a Nonlinear disturbance observer (DO) is designed and combined with ESO based controller to estimate external disturbances. In this simulation study, These ESO-based controllers with and without DO are applied for trajectory tracking, and results are evaluated. An ESO-based Adaptive Backstepping Controller (ABSC) and Adaptive Hybrid controller (AHC) with DO are designed, and performance is evaluated to handle the mass change during the flight despite wind gusts. Simulation results reveal the effectiveness of ESO-based HC with DO compared to ESO-based BSC and ITSMC with DO. Furthermore, an ESO-based AHC with DO is more efficient than an ESO-based ABSC with DO

Closed-loop swing-up and stabilization of inverted pendulum by finite-horizon LQR applied in 2-DOF concept

The general framework of this paper is the control design of complex nonlinear systems. The proposed approach is demonstrated with the use of a case study regarding a typical mechatronic system - control design of inverted pendulum on the cart. The methodology used for the solution of this problem is based on two- degree of freedom control structure (2-DOF) with feed-forward and feedback terms. Feed-forward term represents a solution of trajectory generation problem and feedback term stands for a state controller. Both of these parts generally fall into the category of optimal control problems. The article focuses on the design of a finite-horizon linear quadratic controller and its application in 2-DOF structure with the use of customized LQR computation procedure, showing all necessary steps of the design, including source codes. It is proposed that the developed methodology is general and can be adopted for most of other nonlinear mechatronic systems, including unstable or non-minimum phase systems. This has been already tested successfully for models of both double and triple inverted pendulums. The functionality of the concept under real conditions can also be seen in Ozana (2018a) and Ozana (2018b) showing preliminary experiments with real apparatus

XShields: Cross-platform Application for the Design of Shields against Ionizing Radiation

In many cases medical diagnosis is based on information obtained through a process involving the emission of different forms of ionizing radiation. The safety of the medical staff and patients exposed to ionizing radiation is highly dependent on the proper design of the shielding used in the laboratory. Therefore, the authors propose a multi-platform application supporting such a design through the computation of the critical parameters of shielding. The specific requirements for shielding are defined by government authorities so the algorithm must comply with all the written standards. The application was implemented using Xamarin. Forms for cross-platform development. The results obtained with the use of the developed tool were compared with those calculated manually for the design of stationary shields developed, deployed, and validated by local inspection

Initial Study on Implementation of the Low-Frequency Wave Markers for the Purpose of Diagnostic Tests’ Performance and Neurofeedback Therapy

The paper focuses on automation of signal processing, which also considers analysis of biomedical data, such as EEG. The results of the study prove that this enables a better understanding of signal changes and makes it possible to address some specific disturbances. It also makes it possible to describe the relevant changes in signals mathematically and helps to create markers of various brain disorders. This paper presents the study at the initial stage and focuses on the mathematical markers of concentration disorders associated with Theta waves. The presented markers presented are based on Welch’s periodograms. The obtained results are very promising and further studies aimed at refining them are currently being carried out

Arquivo de Antropologia Física do Museu Nacional: fontes para a história da eugenia no Brasil The National Museum's physical anthropology archive: sources on the history of eugenics in Brazil

Apresenta um conjunto de fontes documentais que integram o Arquivo de Antropologia Física, de responsabilidade do Setor de Antropologia Biológica do Museu Nacional/UFRJ. O arquivo contém importante documentação sobre o Primeiro Congresso Brasileiro de Eugenia, realizado em 1929, no Rio de Janeiro, em comemoração ao centenário da Academia Nacional de Medicina. Além de originais dos trabalhos apresentados no evento - alguns inéditos -, constam também nesse arquivo documentos reunidos pela secretaria do Congresso, como convocações para a sua realização, ficha dos inscritos, correspondências, recortes de jornais e revistas com artigos sobre eugenia, bem como moções, relatórios e atas finais, constituindo acervo fundamental para a compreensão da história da eugenia no Brasil.<br>The article presents a set of documental sources that are part of the physical anthropology archive administered by the National Museum's biological anthropology sector (UFRJ). The archive holds important documentation on the first Brazilian congress of eugenics, held in Rio de Janeiro in 1929, in celebration of the National Academy of Medicine centennial. In addition to the originals of papers presented at the event (some unpublished), the archive also contains a series of documents compiled by the congress organizers, including announcements of the event, attendee registrations, correspondence, newspaper and magazine clippings of articles on eugenics, as well as motions, reports, and final minutes, all of which makes this collection invaluable in understanding the history of eugenics in Brazil