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Ball and beam system is one of the most enduringly popular and important laboratory models for teaching control systems engineering. There are two main problems for ball and beam control: 1) many laboratories use simple controllers such as PD control, but theoretical analysis is based on linear models. 2) nonlinear controllers for ball and beam system have good theory results, but they are seldom...
This paper focuses on the mechanical design of a low-cost picosatellite structure which complies with the CubeSat program design specifications. Being the quasi-static loads bigger than any other expected load, we consider failures due to column bending as a design criteria. The overall design is validated using finite element methods. The satellite structure is treated as a combination of beams and...
In this article, a mathematical model for controlling the end tip position of a single flexible link robot arm is presented. The model is derived using a finite modal approximation for the solution of the Euler-Bernoulli beam equation, with the clamped-free boundary conditions. The link is bounded to move on the horizontal plane, so that the gravity effects on the link are neglected. An appropriate...
For a class of robot arms, a proportional derivative (PD) controller plus gravity compensation yields the global asymptotic stability for regulation tasks, and some proportional integral derivative (PID) controllers guarantee local regulation without gravity cancelation. However, these controllers cannot render asymptotic stability for tracking tasks. In this paper, a simple sliding PID controller...
In this article, we present an on-line piecewise perturbation identification approach, based on algebraic parameter identification methods, for the output feedback control of an unbalanced rotor model with unknown eccentricity parameters, unknown angular velocity and unknown mass. The eccentricity perturbation effects are regarded as unknown perturbations inputs that need to be approximately identified,...
This paper presents the design of a nonlinear robust observer for the estimation of the neutron precursor power and internal reactivity in a nuclear research reactor when only the input and the neutron power are available for measurement. The observer is based on a differential neural network with internal and external layers. Besides, this observer has two correction terms: Luenberger one and sliding...
This paper deals with the problem of semiactive balancing control of a rotor-bearing system, where one journal bearings is supported on two radial Magneto-Rheological (MR) dampers. The mathematical model of the rotor-bearing system results from a Jeffcott-like model and the dynamics associated to the MR dampers, whose rheological properties depend on the current inputs. For control purposes we use...
In this work, the fault diagnosis problem for nonlinear systems is treated, some results based on a differential algebraic approach are used in order to determine fault diagnosability and one nonlinear observer using a sliding mode technique is given for estimating the faults, another nonlinear observer is also treated with the purpose of comparing results. An academic example is presented and faults...
In this paper we address the endurance optimization problem for an electric powered fixed wing aircraft. An endurance equation in terms of aircraft aerodynamics and electric power plant characteristics is obtained. The endurance equation is optimized as a nonlinear problem and handled using optimization constrained techniques. This gives an optimal basic aircraft sizing with maximum endurance.
CuInS2 thin films were prepared on glass substrates with the spray pyrolysis technique. The films were sprayed at 390degC using different ratios of x = [Cu] / [In] in the aqueous solutions with the objective of studying their compositional, structural, optical and electrical properties. The values of the Cu/In ratio in the aqueous solutions have been changed in the range 0.66 - 1.5. SEM photographs...
The aim of this work was to investigate the crystallization properties and crystallization temperature in SbTe thin films, with different content of Sb, using DSC, optical reflection at 650 nm and XRD measurements. DSC studies showed that crystallization temperature of the films depend on the Sb content. XRD measurements have shown that films with low Sb contents (less that 73 at. %) directly crystallized...
An experimental study of the crystallization process of Cu2O samples from polycrystalline copper plates is presented. The crystallization process consists of two stages: In the first stage polycrystalline copper plates were wholly oxidized at 1020 degC in air, in the second stage the Cu2O samples were crystallized through an annealing process at temperatures in the range of 1040-1070 degC, by several...
Cathodoluminescence (CL) spectra for Silicon Rich Oxide (SRO) films with different silicon excess and nitrogen content are measured at room temperature. The SRO was deposited by Low Pressure Chemical Vapor Deposition (LPCVD) on Si substrates, and nitrogen was introduced into SRO adding NH3 to the reactive gases. The samples were divided in two parts, one part was annealed at 1100degC. The nitrogen...
In this work the field emission at atmospheric pressure from palladium oxide (PdO) nanostructures grown on Si (111) is demonstrated. The process for the growth of PdO nanostructures with average height of 9-45 nm is reported. The structure used for measuring de field emission current posses a diode configuration with a separation between cathode and anode plates of 5.6 mum. The current-voltage (I-V)...
Thin film bulk acoustic wave resonator (FBAR) devices have been fabricated using ZnO films grown by RF magnetron sputtering. The FBARs have been characterized by measuring their microwave frequency performance from 2-5 GHz, It was found that the fundamental resonance frequency was 2.367 GHz. The values for the insertion loss (S21), quality factor (Qs) and the effective electromechanical coupling coefficient...
We present a Verilog-A implementation of an Improved Charge Sheet Model (ICSM) for PD SOI MOSFETs. This model is a physical and continuous compact model for deep-submicron transistors focused in an accurate description of high order derivatives, in order to obtain good approximation of the harmonic distortion behavior. The implementation of the model, using Verilog-A language, allows analog circuit...
This paper presents the performance of optimal filtering; LMS with a nonvolatile analog memory cell fabricated through 1.2um CMOS process, for the adaptive identification signal problem, where transfer functions are unknown and changing. The memory stores the weight in the filter as charge on the floating gate of a transistor pMOS. The update is linear, using a pulse density modulation scheme by means...
One-dimensional model of thermoelectric module is suggested, and the lowest temperature of thermoelectric cooling is obtained. It is supposed that cooling occurs due to the classic Peltier's effect, and the thermoelectric module operates in the mode when no external thermal load is applied.
Technological advances mean that increasingly faster speeds are required for data transmission between devices, and also better tools and resources are required for connecting devices. When various solutions are available for solving data transmission problems, it is necessary to compare solutions to decide which is best for a given system. This paper compares two families of FPGAs both suitable for...
In this paper, an evaluation of experimental results from clock distribution networks fabricated for large systems on chip is presented. Typical 3.3 V 0.35 mum CMOS N-well AMIS process parameters were used for the chip fabrication and analysis. It is shown that local networks represent an appropriate approach when used in system on a chip since these networks are comparable in performance to global...
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