Top PDF Stabilization and Control Models of Systems With Hysteresis Nonlinearities

Stabilization and Control Models of Systems With Hysteresis Nonlinearities

Stabilization and Control Models of Systems With Hysteresis Nonlinearities

Mechanical and economic systems with hysteresis nonlinearities are studied in article. Dissipativity condition of inverted pendulum under the hysteresis control is obtained. The solution of the optimal production strategy problem was found where price has hysteresis behaviour.

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Universidade Federal de Minas Gerais Escola de Engenharia Programa de Pós-Graduação em Engenharia Elétrica Estabilização Robusta de Sistemas Não Lineares Incertos Utilizando Representações Algébricas Diferenciais

Universidade Federal de Minas Gerais Escola de Engenharia Programa de Pós-Graduação em Engenharia Elétrica Estabilização Robusta de Sistemas Não Lineares Incertos Utilizando Representações Algébricas Diferenciais

As it will be discussed in Chapter 2, the case of nonlinear systems described by vector fields with uncertain parameters is presented in Section 2.2. Clearly the application of feedback lin- earization procedures for this class of systems relies on the nominal system model and this leads to another nonlinear, instead of linear, dynamical system in new coordinates as will be explained in Section 2.4. Accordingly, the degree of nonlinearity of the resulting system is actually un- known. In this scenario, a natural approach is to consider the resulting system as a new uncertain nonlinear system, whose dynamics is possibly closer to that exhibited by a genuine LTI system, and for which one has to synthesize robust stabilizing control laws. This idea is interesting be- cause it makes amenable the use of more general synthesis procedures for uncertain nonlinear systems to solve the problem of robust stabilization. Moreover, it becomes specially important in those general methods that seem to arise from extensions of the robust control theory for LTI systems, such as gain scheduling relying on uncertain Linear Parameter Varying (LPV) models (Rotondo et al., 2014), or the use of more detailed representations to describe the nonlinearities in the system dynamics (Wang et al., 1992, El Ghaoui and Scorletti, 1996, Coutinho et al., 2002, Franco et al., 2006, Coutinho et al., 2008, Trofino and Dezuo, 2014).
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Global Output Feedback Stabilization of Nonholonomic Chained Form Systems with Communication Delay

Global Output Feedback Stabilization of Nonholonomic Chained Form Systems with Communication Delay

direction of current control technology development and innovation[18-22]. The main feature of a NCS is that the components (sensors, controller and actuators) of the system are not connected directly by wires but using a network. The primary advantages of NCSs are low cost, reduced system wiring, simple installation and maintenance, high reliability and ease of system diagnosis and maintenances. As a result, NCSs have been widely applied to many complicated control systems, such as aviation and aerospace fields, and airplane manufacture [23].
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Methods of solving of the optimal stabilization problem for stationary smooth control systems. Part I

Methods of solving of the optimal stabilization problem for stationary smooth control systems. Part I

where ψ – required first integral; a, b, c with indexes are constants. Taking into account relations of equality of the second mixed deriva- tive from ψ , we shall obtain the intermediate system of the linear al- gebraic equations concerning a, b, c, which solution is the 3-parametric family of matrices of coefficients of the noted above system:

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Global Stabilization of Robot Control with Neural Network and Sliding Mode

Global Stabilization of Robot Control with Neural Network and Sliding Mode

A well known approach to the control of uncertain systems by nonlinear feedback laws is the sliding mode control [1]-[3]. Sliding mode controller design provides a systematic approach to the problem of maintaining stability in the face of modeling imprecision and uncertainty. However, chattering problem is a major drawback of sliding mode control. The boundary layer is used to avoid chattering phenomena [4]. The cost of this technology is a reduction in the accuracy of the tracking performance [5, 6].

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Comput. Appl. Math.  vol.24 número1

Comput. Appl. Math. vol.24 número1

The main difficulties found in the control design for real systems are the nonlin- earities and uncertainties. If we treat nonlinearities as uncertainties the obtained results for stability are in general conservatives. In the last years, attractive sta- bility results for nonlinear systems using Takagi-Sugeno (T-S) fuzzy systems [1] based on the theory of stability of nonlinear systems appeared in Feng et al. [2] and Cao et al. [3]. In the same context, stability conditions using LMIs were given in Hong and Langari [4], Li et al. [5] and Wang et al. [6]. Following this trend, the robust stabilization of uncertain nonlinear systems became an ac- tive field of research wherein available robust control techniques for uncertain
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Synthesis of nanoparticeles in ductile iron with small additions of vanadium and niobium and its mechanical properties

Synthesis of nanoparticeles in ductile iron with small additions of vanadium and niobium and its mechanical properties

The another important finding revealed by TEM was the presence of extremely small precipitates which occurred in all examined areas (Fig. 3a). The precipitates, with a diameter on the order of a few nm, gave rise to the typical type of contrast characteristic for large strain fields. The precipitates have a crystalline nature since the they showed the contrast only at certain specimen positions (specimen tilt angle) and produced some extra spots on SAD patterns (Fig. 3b). These relatively strong extra spots along with strain field contrast throughout the samples suggests fairly large volume fraction of these precipitates as well as their coherency with iron matrix. The diffuse extra spots on some diffration patterns and their proximity to the central spot may point to short ordered character of these precipitates. Though the data collected from the TEM investigation turned out to be not sufficient for identification of these precipitates, however, the occurrence of such precipitates was associated with Si content: the higher Si content the more distinct contrast in the TEM images and stronger extra spots on diffraction patterns. This observation was verified by examination of samples containing 2 to and 4.5% of Si. It can be concluded that the stronger is extra spots on diffraction patterns the higher is Rm and R o.2 and lower elongation A
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Quality control of cast brake discs

Quality control of cast brake discs

Investigation of measurement thickness for working part brake - discs effected at help of slide calliper with exactitude 0, 1 mm. Producers nominal data thickness for examined working part brake - discs represent as follows: for not ventilated disc value in range 10,8-11,1 mm and for ventilated brake disc value in standard 24 mm.

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OPTIMAL CONTROL FOR ELECTRIC VEHICLE STABILIZATION

OPTIMAL CONTROL FOR ELECTRIC VEHICLE STABILIZATION

Considering a direct mechanical contact of the steering wheel, for improving handling and stability of vehicle the performance of the proposed control is evaluated under a step lane maneuver by numerical simulation. The optimal control regulates the system responses (state trajectories of the state vector close to origin without excessive control demand) and assure an asymptotically vehicle system such that the performance index (14) is minimized. The obtained results show that the feasibility of the proposed control solution.
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ELEMENTS OF CONTROL OVER HIERARCHIE SYSTEMS WITH ASSUMED HIERARCHY

ELEMENTS OF CONTROL OVER HIERARCHIE SYSTEMS WITH ASSUMED HIERARCHY

The article presents a mathematical model of control over dynamic hierarchy system. The model was proposed for dealing with systems with assumed order in the technical problem of predicting destructions depending onto the amount of defects on different scale levels. The problem of the closest to a certain point of shelf life of hierarchy system is solved. The example of approach control during the given time is given. The problem concerns mathematic

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Epilepsy-induced electrocardiographic alterations following cardiac ischemia and reperfusion in rats

Epilepsy-induced electrocardiographic alterations following cardiac ischemia and reperfusion in rats

Monitoring, recording, and ECG waveform analysis The ECG of the rats was monitored and recorded from the beginning of the stabilization period using a commercial acquisition system (AqDados 7.02; Lynx Tecnologia Ltda., Brazil). The recorded raw data were evaluated using the commercial software included in the acquisition system (AqDAnalysis 7, Lynx Tecnologia Ltda.; Figure 1). Heart rate as well as incidence of reperfusion-induced VA, AVB, and lethality were measured. To simplify the presentation of the results, ventricular fibrillation, torsades de pointes, and ventricular tachycardia parameters were considered only as VA. ECG measurements were evaluated according to Lambeth conventions (28,29). P duration was manually measured as the time from the beginning of the upstroke of the P wave until its return to the isoelectric baseline. QRS duration was measured from the beginning of the Q wave to the peak amplitude of the downward deflection of the S wave. PR interval was measured from the beginning of the upstroke of the P wave until the maximal amplitude of the R wave. RR interval was measured as the time between consecutive R wave peaks. QT interval was measured from the beginning of the Q wave until the T wave returned to the isoelectric baseline (30).
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RGO, Rev. Gaúch. Odontol.  vol.64 número4

RGO, Rev. Gaúch. Odontol. vol.64 número4

The use of rapid prototyping in medical and dental ields consists of three-dimensional models using Computer Aided Design systems and Computer Aided Manufacturing systems. Such systems focus speciically on enhanced 3D visualization tools that provide a precise preoperative planning opportunity through three-dimensional printing, to the professional. The objective of this study was to describe the main steps in the biomodel manufacturing using an Objet 3D printer (CONNEX 350), whose raw material is a light-curing resin. The steps are adopted by researchers from three-dimensional technologies laboratory (LT3D), of the Center for Strategic Technologies in Health (NUTES), from the State University of Paraíba (UEPB), Brazil. It begins with the acquisition of tomographic images that are processed through speciic software and exported to the digital Stereo lithography (STL) format. The additive manufacturing technique is Stereo lithography, which consists in the construction of biomodel by photopolymerization of a liquid epoxy resin using ultraviolet radiation. The biomodel that comes from this process was brought to a pressurizing machine to remove the resin support, washing it with water jets. After this step, this biomodel was sent to the health professional in charge. The use of biomodels constitutes a major breakthrough in the area of Dentistry, allowing more precise diagnosis by professionals, simulation and surgical planning, previous adaptation of biomaterials and orthoses, as well as interaction between the surgeon and the patient, thus obtaining more satisfactory aesthetic results and decreased surgical time.
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Microstructural and mechanical properties of gravity-die-cast A356 alloy inoculated with yttrium and Al-Ti-B grain refiner simultaneously

Microstructural and mechanical properties of gravity-die-cast A356 alloy inoculated with yttrium and Al-Ti-B grain refiner simultaneously

Aluminium alloys constitute a significant proportion of lightweight metals used in various industries for applications ranging from automotive components to aerospace parts etc [4]. There is always a constant need to improve the microstructure and its inherent mechanical properties of aluminium alloys castings due to the increasing awareness of reducing green house emissions by using lightweight materials in automotive industries. Aluminium alloys are known to have excellent strength to weight ratio compared with other conventional metals like steels. A356 is one of the most widely used aluminium alloys in many industrial applications because of its excellent castability, corrosion resistance and good mechanical properties. It has lower production cost, fast machining rate and good recyclability. Typical commercial grain refiners use to refine A356 aluminium castings are Al-Ti-B and Al-Ti-C master alloys. The efficiency of these grain refiners can be easily undermined by alloying elements like Zr and V [5]. In recent years, yttrium has been regarded as a promising element in superalloys for its ability to improve creep property and oxidation resistance of cast stainless steel [6-7]. However, very little work was done to investigate the effect of yttrium on the grain refining efficiency of Ti-B based grain refiner in A356 casting. Therefore, the research presented by this paper intends to study the effect of rare earth yttrium on the grain refinement efficiency of Al-T-B master alloy by using gravity die casting as the casting process.
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Stabilization of guava nectar with hydrocolloids and pectinases

Stabilization of guava nectar with hydrocolloids and pectinases

The soluble solids content of the guava nectar formulations were significantly higher (14.03 ± 0.12), when compared to the control, except for the formulation with guar gum (T3). The increase in soluble solids was expected, due to the addition of solids in all formulations. The formulation with the pectinase enzyme and rice flour (T8) was the one with the highest amount of soluble solids (16.10 °Brix), and the highest values were observed in the formulations containing pectinases enzymes (T5, T6, T7, T8). These results are probably due to the action of the pectinolytic enzymes that hydrolyze the α (1→4) glycosidic bonds, which increases the soluble solids content in solution. According to Sreenath et al. [29] the enzyme improves the quality of the
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Mitigation of Power Quality Issues by Nine Switches UPQC Using  PI & ANN with Hysteresis Control

Mitigation of Power Quality Issues by Nine Switches UPQC Using PI & ANN with Hysteresis Control

V. DESIGNING & TRAINING OF ANN An ANN is essentially a cluster of suitably interconnected non-linear elements of very simple form that possess the ability of learning and adaptation. These networks are characterized by their topology, the way in which they communicate with their environment, the manner in which they are trained and their ability to process information [18]. Their ease of use, inherent reliability and fault tolerance has made ANNs a viable medium for control. An alternative to fuzzy controllers in many cases, neural controllers share the need to replace hard controllers with intelligent controllers in order to increase control quality [19]. A feed forward neural network works as compensation signal generator. This network is designed with three layers. The input layer with seven neurons, the hidden layer with 21 and the output layer with 3 neurons. Activation functions chosen are tan sigmoidal and pure linear in the hidden and output layers respectively.
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Structure of X5CrNi18-10 and S355NL Steels after Remelting with the Electric Arc

Structure of X5CrNi18-10 and S355NL Steels after Remelting with the Electric Arc

The tested steels have wide application as a construction material, meeting particular conditions of loading during exploitation. Steel S355NL is often used in building constructions and machine construction, operating, among others areas in mining, drilling and motor industry. Steel X5CrNi18-10 according to the standard PN-EN 10088, is ranked as resistant to corrosion. It is used in many industrial branches such as in food and chemical industry, in devices used in medicine or households. The type is widely used due to its chemical capacity in contact with many types of chemical compounds.
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A Model Transformation Environment for Embedded Control Software Design with Simulink Models and UML Models

A Model Transformation Environment for Embedded Control Software Design with Simulink Models and UML Models

We consider the case in which the calculation of the values of EngineRevolution, EngineStatus and AcceleratorOpening and the calculation of the values of TargetTorque and Throt- tleOpening are executed by different periodic task. If the priority of the former task is higher than the priority of the latter task, the latter task may be preempted by the former task. So a mechanism of mutual exclusion or inter- task communication is needed for data integrity. Here, we use buffering mechanism, which is one of wait-free inter-task communications. Figure 5 shows the class diagram of the aspect pattern of buffering, which connects a producer object and a consumer object. Class Buffer has attribute buf to store the value, method update to get the value from Producer and store the value in buf, and method get for Consumer to get the value stored in buf. The class diagram of the aspect pattern is enclosed by a package with stereotype <<aspect>>, which represents that the enclosed diagram is an aspect.
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Digital controller design considering hardware constraints: application in a paraplegic patient

Digital controller design considering hardware constraints: application in a paraplegic patient

linearized model of the plant. This result was expected, because according to Ogata (2011), the linear system exhibits the same behavior as the non-linear system only in a region very close to the operation point. However, by analyzing Figure 8, it is observed that the differences between the responses obtained with Matlab and ISIS Proteus were small, demonstrating the feasibility of the implementation of the hardware considered and of the control algorithm embedded in it. Although the controller was designed with the linearized model of the plant, in Figure 8 it is observed that the design specifications were met. Thus, the non-linearities of the plant neglected in the linearization process did not affect the response of the system.
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Simultaneous Determination Of Adjusted Ranks Of Sample Observations And Their Sums And Products

Simultaneous Determination Of Adjusted Ranks Of Sample Observations And Their Sums And Products

Sometimes one may have a sample drawn from a population that may be a measurement on as low as the ordinal scales that are not necessarily continuous or even numeric. Research interest is in using ranks instead of raw scores in statistical analyses. In this case one may have to first assign ranks to each of the observations before further analyses. A problem that often arises is how to systematically assign ranks to these data without having to arrange them in any order, either from the smallest to the largest or from the largest to the smallest. It is acknowledged that several methods exist for generating rank sums, products, sums of squares and breaking of ties between sample observations in their rankings (Gibbons J. D. 1973; Hollander and Wolfe, 1999; Siegel Sidney, 1956; Oyeka et al, 2014) adopting different approaches. We, in this paper, propose to develop a statistical method along the line of Oyeka et al (2013) to help in systematically assigning ranks to a sample of observations without first arranging them in any order. We also develop a statistical method for the estimation of the sums of squares and products of ranks in the presence of tied observations in which some or all the observations are tied and therefore assigned mean ranks.
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Synchronization Criteria of Chaos Systems with Time-delay Feedback Control

Synchronization Criteria of Chaos Systems with Time-delay Feedback Control

For the time-delay feedback control of chaos synchronization problem, an idea of Lyapunov functional with time-delay decomposition is presented. Some delay-dependent synchronization criteria are formulated in the form of matrix inequalities. The controller gain with maximum allowed time- delay can be achieved by solving a set of linear matrix inequalities (LM Is). A simulation example is given to illustrate the effectiveness of the design method.

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