Search results for "Ar system"
showing 10 items of 6176 documents
Estimation of Sway-angle Based on Hybrid State Observer Using Continuous and Discrete Sensing
2019
A hybrid state observer design is presented herein to estimate sway-angle and angular velocity in trolley systems with pendulum. In general, anti-sway control for trolley systems with pendulum such as overhead cranes are designed based on sway-angle signals detected by angular sensors. Opposed to that, a state observer without those sensors is proposed to estimate the sway-angle of the pendulum. A standard linear continuous feedback observer causes estimation error owing to the system nonlinearity and modeling error. This paper proposes a hybrid state observer incorporating discrete sensor signals. In the hybrid state observer, the estimation performance is improved by correcting the state …
Parallel distributed compensation for voltage controlled active magnetic bearing system using integral fuzzy model
2018
Parallel Distributed Compensation (PDC) for current-controlled Active Magnetic Bearing System (AMBS) has been quite effective in recent years. However, this method does not take into account the dynamics associated with the electromagnet. This limits the method to smaller scale applications where the electromagnet dynamics can be neglected. Voltage-controlled AMBS is used to overcome this limitation but this comes with serious challenges such as complex mathematical modelling and higher order system control. In this work, a PDC with integral part is proposed for position and input tracking control of voltage-controlled AMBS. PDC method is based on nonlinear Takagi-Sugeno (T-S) fuzzy model. …
Fuzzy Modeling for Uncertain Nonlinear Systems Using Fuzzy Equations and Z-Numbers
2018
In this paper, the uncertainty property is represented by Z-number as the coefficients and variables of the fuzzy equation. This modification for the fuzzy equation is suitable for nonlinear system modeling with uncertain parameters. Here, we use fuzzy equations as the models for the uncertain nonlinear systems. The modeling of the uncertain nonlinear systems is to find the coefficients of the fuzzy equation. However, it is very difficult to obtain Z-number coefficients of the fuzzy equations.
State Observer with Round-Robin Aperiodic Sampled Measurements with Jitter
2021
International audience; A sampled-data observer is proposed for linear continuous-time systems whose outputs are sequentially sampled via non-uniform sampling intervals repeating a prescribed Round-Robin sequence. With constant sampling intervals (jitter-free case) we provide constructive necessary and sufficient conditions for the design of an asymptotic continuous-discrete observer whose estimation error is input-to-state stable (ISS) from process disturbances and measurement noise. We use a time-varying gain depending on the elapsed time since the last measurement. With non-constant sampling intervals (jitter-tolerant case), our design conditions are only sufficient. A suspension system …
Linearized Piecewise Affine in Control and States Hydraulic System: Modeling and Identification
2018
In this paper, the modeling and identification of a nonlinear actuated hydraulic system is addressed. The full-order model is first reduced in relation to the load pressure and flow dynamics and, based thereupon, linearized over the entire operational state-space. The dynamics of the proportional control valve is identified, analyzed, and intentionally excluded from the reduced model, due to a unity gain behavior in the frequency range of interest. The input saturation and dead-zone nonlinearities are considered while the latter is identified to be close to 10% of the valve opening. The mechanical part includes the Stribeck friction detected and estimated from the experiments. The lineariza…
On stability of linear dynamic systems with hysteresis feedback
2020
The stability of linear dynamic systems with hysteresis in feedback is considered. While the absolute stability for memoryless nonlinearities (known as Lure's problem) can be proved by the well-known circle criterion, the multivalued rate-independent hysteresis poses significant challenges for feedback systems, especially for proof of convergence to an equilibrium state correspondingly set. The dissipative behavior of clockwise input-output hysteresis is considered with two boundary cases of energy losses at reversal cycles. For upper boundary cases of maximal (parallelogram shape) hysteresis loop, an equivalent transformation of the closed-loop system is provided. This allows for the appli…
Dissipativity-Based Small-Gain Theorems for Stochastic Network Systems
2016
In this paper, some small-gain theorems are proposed for stochastic network systems which describe large-scale systems with interconnections, uncertainties and random disturbances. By the aid of conditional dissipativity and showing times of stochastic interval, small-gain conditions proposed for the deterministic case are extended to the stochastic case. When some design parameters are tunable in practice, we invaginate a simpler method to verify small-gain condition by selecting one subsystem as a monitor. Compared with the existing results, the existence-and-uniqueness of solution and ultimate uniform boundedness of input are removed from requirements of input-to-state stability and smal…
Drenaggio toracico in Pronto Soccorso
2021
Riassunto Il drenaggio toracico e una procedura comune in medicina d’urgenza, indicata per gli pneumotoraci spontanei (primari o secondari) o traumatici e i versamenti pleurici liquidi: emotorace, pleurite purulenta o versamento parapneumonico complicato. Il drenaggio toracico si inserisce in una gestione multidisciplinare che coinvolge urgentisti, pneumologi, chirurghi toracici e rianimatori. La tecnica utilizzata deve essere nota ai medici che prendono in carico questi pazienti. Possono essere utilizzati diversi tipi di drenaggio e le loro indicazioni differiscono a seconda della natura del versamento. Il classico drenaggio con trocar resta, attualmente, indicato in caso di versamento liq…
Detección sistemática del cáncer colorrectal
2019
El cancer colorrectal, uno de los principales problemas de salud publica, cumple con las condiciones para la deteccion en la poblacion general. Los resultados disponibles muestran que una prueba de sangre oculta en heces puede reducir la mortalidad por cancer colorrectal. Por eso, la Comision Europea recomienda la realizacion de esta deteccion en las poblaciones de riesgo. En la actualidad, nuevas pruebas, las pruebas inmunologicas que permiten una lectura automatizada y cuantitativa, han sustituido a las pruebas de primera generacion, las pruebas del guayacol. Representan un gran avance: duplican la tasa de deteccion de canceres y multiplican por 3-4 la de los adenomas con alto riesgo de t…
Rezept für Bewegung in der Nephrologie
2018
ZusammenfassungDie Behandlung der chronischen Niereninsuffizienz (chronic kidney disease, CKD) in Klinik und Praxis, auch unter der Dialysetherapie, beinhaltet stets eine umfangreiche medikamentöse Gabe und eine regelmäßige Überwachung. Die Niereninsuffizienz als chronische Erkrankung gehört zu der Gruppe von Krankheiten, die auch von einer nicht medikamentösen Therapie profitiert – nämlich von einer regelmäßigen körperlichen Aktivität. Trotz zahlreicher Publikationen zu diesem Thema werden Bewegung und körperliche Aktivität noch zu wenig bei Patienten mit CKD eingesetzt. Mit den Ergebnissen des Trainings während der Dialyse und dem Rezept für Bewegung gibt es effektive Ansätze, die Faktore…