Actuator Fault Estimation (FE) and Fault Tolerant Control (FTC) strategies designed with model-based observers for Vertical TakeOff and Landing (VTOL) aerial vehicles are proposed and validated experimentally in this paper. Three observers are considered for FE: a nonlinear adaptive observer and a linear Proportional-Integral Observer (PIO) applied to a Planar VTOL and a quasi-Linear Parameter Varying (qLPV) PIO applied to a quadcopter vehicle. The fault detection is done by comparing the fault estimation signal with a predefined threshold. Fault isolation is achieved by analyzing the sign of the fault estimation signal. The Available Control Authority Index (ACAI) method is used to analyze the controllability properties of the vehicles under actuator faults. The main contribution of this work is the design and the experimental validation of complete active FTC schemes by using the proposed FE systems in order to accommodate a soft actuator fault and reconfigure an aggressive fault, even when the vehicle is flying in a non-hover position. Finally, the proposed FTC schemes are validated in different cases of flight tests for illustrating the effectiveness of the strategies.

In this article, various investigations on soft exoskeletons are presented and their functional and structural characteristics are analyzed. The present work is oriented to the studies of the last decade and covers the upper and lower joints, specifically the shoulder, elbow, wrist, hand, hip, knee, and ankle. Its functionality, applicability, and main characteristics are exposed, such as degrees of freedom, force, actuators, power transmission methods, control systems, and sensors. The purpose of this work is to show the current trend in the development of soft exoskeletons, in addition to specifying the essential characteristics that must be considered in its design and the challenges that its construction implies.

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El objetivo de la presente investigación fue identificar las características, conductas y herramientas docentes que, según el estudiantado de una licenciatura en recursos humanos del occidente de México, promovieron el aprendizaje durante las clases en línea durante la COVID-19. La investigación fue cualitativa, no experimental, exploratoria y transversal. Se aplicó un cuestionario de respuestas abiertas, a 109 participantes (78% mujeres y 22% hombres; 22.6 años de edad promedio). Como resultado se tiene que el profesorado que promueve el aprendizaje se caracteriza por ser explicativo, comprensivo, paciente, dinámico y empático; en términos conductuales explica los temas, programa actividades prácticas, da constantemente retroalimentación, establece tareas flexibles y está disponible para el alumnado cuando se requiere. Además, se obtuvo que las herramientas docentes más eficaces fueron los videos, diapositivas, videollamadas, aulas virtuales y repositorios digitales.

Extractive distillation with salts, unlike other dehydration technologies, is better due to the null toxicity that exists in the distillate, since salt cannot be evaporated. With this distillation technology, it is possible to obtain a high concentration of ethanol, however, there are still problems in the control of the distillation columns in the presence of disturbances. The present work deals with the simulation and control of an extractive distillation column using CaCl2 as a separating agent, for which the Aspen Dynamics® simulator is used. The measurement and control of the ethanol composition are carried out by means of temperature, in addition, four control structures are evaluated and compared. These structures are L, D, LV, and DV, which are the most common in conventional distillation, and their performance is measured by means of deterministic indicators applying changes (disturbances) of composition and the flow rate in the main feed of the column. The most relevant results of this work lead to the fact that by applying a controller, it is possible to maintain the desired purity above the international purity standards (99% ethanol) that govern biofuels.