Process operating mode monitoring : switching online the right controller

This paper presents a structure which deals with process operating mode monitoring and allows the control law reconfiguration by switching online the right controller. After a short review of the advances in switching based control systems during the last decade, we introduce our approach based on the definition of operating modes of a plant. The control reconfiguration strategy is achieved by online selection of an adequate controller, in a case of active accommodation. The main contribution lies in settling up the design steps of the multicontroller structure and its accurate integration in the operating mode detection and accommodation loop. Simulation results show the effectiveness of the operating mode detection and accommodation (OMDA) structure for which the design steps propose a method to study the asymptotic stability, switching performances improvement, and the tuning of the multimodel based detector

Unsupervised Contact Learning for Humanoid Estimation and Control

This work presents a method for contact state estimation using fuzzy clustering to learn contact probability for full, six-dimensional humanoid contacts. The data required for training is solely from proprioceptive sensors - endeffector contact wrench sensors and inertial measurement units (IMUs) - and the method is completely unsupervised. The resulting cluster means are used to efficiently compute the probability of contact in each of the six endeffector degrees of freedom (DoFs) independently. This clustering-based contact probability estimator is validated in a kinematics-based base state estimator in a simulation environment with realistic added sensor noise for locomotion over rough, low-friction terrain on which the robot is subject to foot slip and rotation. The proposed base state estimator which utilizes these six DoF contact probability estimates is shown to perform considerably better than that which determines kinematic contact constraints purely based on measured normal force.Comment: Submitted to the IEEE International Conference on Robotics and Automation (ICRA) 201

Beneficios clínicos de los ácidos grasos Omega 3 en esquizofrenia

La esquizofrenia es una enfermedad mental grave del grupo de las psicosis cuya etiología está aún hoy en día sin determinar de forma fiable, que cursa con numerosas alteraciones biológicas y conlleva un alto deterioro de la funcionalidad, la independencia y la calidad de vida de quien la padece. El omega 3 es un ácido graso poliinsaturado de cadena larga que ha mostrado múltiples beneficios para la salud humana, tanto física como mental, pero que debe consumirse a través de la dieta. Numerosos estudios han aportado evidencia de que los pacientes con esquizofrenia presentan una insuficiencia de omega 3, bien por un estilo de vida poco saludable, bien por mecanismos metabólicos alterados propios de la enfermedad o de la medicación antipsicótica. Esta revisión resulta especialmente relevante para determinar las principales características que subyacen al potencial restablecimiento clínico, metabólico y funcional tras la intervención nutricional con omega 3 en esquizofrenia. El objetivo del presente trabajo es determinar los posibles beneficios clínicos del tratamiento suplementario con omega 3 en pacientes con esquizofrenia: mejora en índices sintomatológicos, funcionales, antropométricos, metabólicos o de neuroinflamación. Para ello, se realizó una revisión sistemática de la bibliografía disponible hasta la fecha escogiendo los principales motores de búsqueda y bases de datos, tanto en inglés como en español. Además de las características de la suplementación con omega 3, se analizaron variables tales como el tipo de paciente, el tratamiento aplicado o las herramientas de evaluación. Los resultados de nuestra revisión revelan que los ácidos grasos omega 3 parecen tener beneficios clínicos significativos como tratamiento coadyuvante a la terapia farmacológica en pacientes con esquizofrenia. Sin embargo, esto no ocurre en todas las variables estudiadas, ni todos los tipos de pacientes se ven beneficiados, por lo que más investigación se hace necesaria para determinar las mejores condiciones y contextos de aplicación.Grado en Nutrición Humana y Dietétic

Fachadas mendocinas : la identidad de lo culto y lo popular

Fil: Rotella, María Inés. Universidad Nacional de Cuyo. Facultad de Artes y Diseñ

Trajectory generation for multi-contact momentum-control

Simplified models of the dynamics such as the linear inverted pendulum model (LIPM) have proven to perform well for biped walking on flat ground. However, for more complex tasks the assumptions of these models can become limiting. For example, the LIPM does not allow for the control of contact forces independently, is limited to co-planar contacts and assumes that the angular momentum is zero. In this paper, we propose to use the full momentum equations of a humanoid robot in a trajectory optimization framework to plan its center of mass, linear and angular momentum trajectories. The model also allows for planning desired contact forces for each end-effector in arbitrary contact locations. We extend our previous results on LQR design for momentum control by computing the (linearized) optimal momentum feedback law in a receding horizon fashion. The resulting desired momentum and the associated feedback law are then used in a hierarchical whole body control approach. Simulation experiments show that the approach is computationally fast and is able to generate plans for locomotion on complex terrains while demonstrating good tracking performance for the full humanoid control

Single-cell protein dynamics reproduce universal fluctuations in cell populations

Protein variability in single cells has been studied extensively in populations, but little is known about temporal protein fluctuations in a single cell over extended times. We present here traces of protein copy number measured in individual bacteria over multiple generations and investigate their statistical properties, comparing them to previously measured population snapshots. We find that temporal fluctuations in individual traces exhibit the same universal features as those previously observed in populations. Scaled fluctuations around the mean of each trace exhibit the same universal distribution shape as found in populations measured under a wide range of conditions and in two distinct microorganisms. Additionally, the mean and variance of the traces over time obey the same quadratic relation. Analyzing the temporal features of the protein traces in individual cells, reveals that within a cell cycle protein content increases as an exponential function with a rate that varies from cycle to cycle. This leads to a compact description of the protein trace as a 3-variable stochastic process - the exponential rate, the cell-cycle duration and the value at the cycle start - sampled once each cell cycle. This compact description is sufficient to preserve the universal statistical properties of the protein fluctuations, namely, the protein distribution shape and the quadratic relationship between variance and mean. Our results show that the protein distribution shape is insensitive to sub-cycle intracellular microscopic details and reflects global cellular properties that fluctuate between generations

Momentum Control with Hierarchical Inverse Dynamics on a Torque-Controlled Humanoid

Hierarchical inverse dynamics based on cascades of quadratic programs have been proposed for the control of legged robots. They have important benefits but to the best of our knowledge have never been implemented on a torque controlled humanoid where model inaccuracies, sensor noise and real-time computation requirements can be problematic. Using a reformulation of existing algorithms, we propose a simplification of the problem that allows to achieve real-time control. Momentum-based control is integrated in the task hierarchy and a LQR design approach is used to compute the desired associated closed-loop behavior and improve performance. Extensive experiments on various balancing and tracking tasks show very robust performance in the face of unknown disturbances, even when the humanoid is standing on one foot. Our results demonstrate that hierarchical inverse dynamics together with momentum control can be efficiently used for feedback control under real robot conditions.Comment: 21 pages, 11 figures, 4 tables in Autonomous Robots (2015