Top PDF Dynamic Modeling of a Multiple Launch Rocket System

Dynamic Modeling of a Multiple Launch Rocket System

Dynamic Modeling of a Multiple Launch Rocket System

In this paper, dynamic model of a multiple launch rocket system with electromechanical actuators is constructed and the mechanisms for azimuth and elevation are explained. Performances of four different friction models are evaluated on the azimuth axis by comparing simulation results with data measured from the actual system. The Coulomb+ Viscous+StartUp friction model is shown to be the best alternative for the application. This friction model is then implemented into the elevation axis model, which is more complicated than the azimuth axis model due to unbalance loading. It is shown, by comparing the elevation simulations with the test data, that the model is accurate within, on average, 5% of the actual system.
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Modeling and Analysis of a LOXEthanol Liquid Rocket Engine

Modeling and Analysis of a LOXEthanol Liquid Rocket Engine

A liquid rocket engine can be divided into feed system and thrust chamber assembly. The feed system is responsible to lead the propellants to the thrust chamber providing enough pressure energy to overcome all pressure losses in the lines and components and reaching the established combustion chamber pressure. To provide such pressure energy, pressure-fed and turbopump fed system are the options available for launch vehicles technology. The turbopump assembly (TPA) is designated to delivery the required energy to the propellants. Although many configurations of turbopump fed cycle can be found in the literature, most of them are derived from the traditional gas generator cycle (GG), staged combustion (SC), and expander cycle (EC). Another way to categorize the engine cycles is based on the turbine and thrust chamber arrangement. In other words, the cycles can be classified as open or closed. In an open cycle, the turbine is in parallel with the thrust chamber, and the drive gases are either dumped overboard or injected in the divergent section of the nozzle.
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ESA ExoMars: Pre-launch PanCam Geometric Modeling and Accuracy Assessment

ESA ExoMars: Pre-launch PanCam Geometric Modeling and Accuracy Assessment

The ExoMars PanCam system consists of a pair of identical Wide-Angle Cameras (WAC) and one High-Resolution Camera (HRC). The WAC has a larger field of view (FOV) angle i.e. 34° whereas the HRC only has a FOV of 5° (Paar et al., 2010). This can be compared with the MER mission’s Navcam 45° FOV and Pancam 16° FOV (Griffiths et al., 2006). However the HRC’s much longer focal length empowers it can ‘see’ much farther than the WAC. Provided these important characteristics, we have also studied how incorporating the HRC impacts attainable accuracy levels for mapping and localization. The attainable level of accuracy is first analyzed theoretically based on a rover traverse involving only two sites. Then, analysis is extended to a long, multiple-site traverse scenario. In the two- site rover localization model, the location of the rover at the first site is fixed. The location of the rover at the second site is determined by identification of matching features between these two sites. We assume that the only possible errors are those in the measurements of the image coordinates of the features.
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Dynamic response analysis of the electro-pneumatic module of a continuous positive airway pressure in newborns using Bond Graph modeling

Dynamic response analysis of the electro-pneumatic module of a continuous positive airway pressure in newborns using Bond Graph modeling

The Continuous Positive Airway Pressure for Newborns (Neo-CPAP) device is used to maintain the airway at a pressure above the ambient throughout the breathing, and thus preventing the complete removal of the in- spired gas, while maintaining high stability. This technique was applied in cases of hya- line membrane disease in 1971, in which the use of this treatment was able to maintain a normal spontaneous breathing rate with ex- cellent results (Lima et al., 2004). Currently its application occurs mainly among newborns of very low weight, since this technique pro- vides increased functional residual capacity (FRC), pulmonary compliance (PC) and espe- cially the reduction of intrapulmonary devia- tion, in which an improper deviation occurs in the ventilation-perfusion ratio (V/Q), besides the reduction of oxygen diff usion (Kamper, 1999). In a study conducted by Mayor (2010), a chronology of the equipment evolution is pre- sented. The results show delimitations of char- acteristic functions of operation, handling, con- solidated and strongly validated applications (Bonassa, 2000; Borges et al., 2003; Carvalho, 2000; Carvalho e Bonassa, 2000; Postiaux, 2004). However, mathematical models of this disposi- tive are rare and they are often models that use phenomenological laws for obtaining the con- stitutive relations of the basic elements of the pneumatic system. To overcome this limitation, a study was elaborated to obtain a mathemati- cal model of the electro-pneumatic structure of the developed prototype Neo-CPAP. The the- ory used in this study is Bond Graph (BG), a graphing tool developed by H. M. Paytner in 1959 used to describe the physical interactions between physical systems, mechanical, hydrau- lic, electrical, pneumatic quantities, among oth- ers (Rodrigues, 2009). Bond Graph is meant to represent the exchange of energy among com- ponents of a physical system and the compres- sion of the interaction among the components. In general, as literature provides, pneumatic systems are fl uid systems that have multiple subsystems with non-linearities, such as com- pressibility of the air, holes, friction and losses (Garcia, 2009; Guenther et al., 2006). According to Von Linsingen (2001), a hydraulic system is a device by which an input of energy is con- verted and conditioned into useful mechani- cal energy. In this context, electro-pneumatic system of Neo-CPAP fi ts because it is a fl uid power system.
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Dynamic modeling of a compressed air energy storage system in a grid connected photovoltaic plant

Dynamic modeling of a compressed air energy storage system in a grid connected photovoltaic plant

The other possible operational condition is when the solar energy ramps make the PV farm to not be able to cover the grid demand. For this case, the stored compressed air is reclaimed to be used for generating power by passing through the multiple stage expander set. Naturally, the air should be preheated before being expanded. This is why the heating process in three phases is proposed to be accomplished before each stage of expansion. The first stage of preheating is done with solar heat exchangers supported by the solar heating system. In fact, the hot working fluid stored in the storage tank flows through the shell and tube solar heat exchangers and warms up the air stream up to possible temperatures. In the next step of preheating, the heat stored in the thermal energy storage tank 1 is employed for heating the air stream. These heat exchangers are also shell and tube type. Finally, if still air needs to be heated to higher temperatures, the auxiliary diesel air heaters could be used. After being heated, the air passes through the expanders and runs the turbines. The turbine shaft is synchronized by an electricity generator device and it produces power as much as required. It should be noted that the system is so designed that the air mass flow rate is regulated according to the amount of power shortage in the PV farm. It is also noteworthy that the working fluid outgoing from the solar heat exchangers comes back to the solar storage tank and the working fluid outgoing from the heating heat exchangers goes into the other thermal energy storage tank (No. 2).
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Using an MPI Cluster in the Control of a Mobile Robots System

Using an MPI Cluster in the Control of a Mobile Robots System

Abstract—Recently, HPC (High Performance Computing) systems have gone from supercomputers to clusters. The clusters are used in all tasks that require very high computing power such as weather forecasting, climate research, molecular modeling, physical simulations, cryptanalysis, etc. The use of clusters is increasingly important in the scientific community, where the need for high performance computing (HPC) is still growing. In this paper, we propose an improvement of a mobile robots system control by using an MPI (Message Passing Interface) cluster. This cluster will launch, manipulate and process data from multiple robots simultaneously.
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Bidirectional coupling between astrocytes and neurons mediates learning and dynamic coordination in the brain: a multiple modeling approach.

Bidirectional coupling between astrocytes and neurons mediates learning and dynamic coordination in the brain: a multiple modeling approach.

For many years, astrocytes, a subgroup of glial cells found in the brain, have been thought to support neurons by providing them with vital elements needed for their survival [1–3]. In recent years, several new discoveries have revealed that astrocytes can encapsulate ,10 5 synapses and can connect to multiple neighboring neurons [4,5]. Although astrocytes cannot elicit propagating action potentials (APs) like neurons do, they can communicate in a bidirectional manner with neurons and other astrocytes by release of transmitters (which include glutamate and adenosine triphosphate (ATP) referred to as gliotransmitters) and propagating calcium (Ca 2+ ) waves. In particular, the interaction of glutamate with astrocytic receptors leads to transient elevation in astrocytic intracellular Ca 2+ levels [6–9], which represent a fundamental mode of excitation in astrocytes. In response to these Ca 2+ transients, astrocytes release gliotransmitters which in turn modulate synaptic transmission by acting both on pre- and post-synaptic receptors. As well as intracellular communication, astrocytes communicate with each other through the propagation of Ca 2+ waves, a process which is thought to be mediated via extracellular ATP diffusion and the transmission of inosotil 1, 4, 5-trisphosphate
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ROCKET PRODUCTION IN A LOW COST HYDROPONIC SYSTEM USING BRACKISH WATER

ROCKET PRODUCTION IN A LOW COST HYDROPONIC SYSTEM USING BRACKISH WATER

The Brazilian semiarid region has low and irregular precipitation, and high evapotranspiration rate, which result in a negative water balance. In addition, its soils have predominance of crystalline rocks, which generate high salt rates in the available water, especially in subsoil waters (SANTOS et al., 2010; SOARES et al., 2010), increasing limitations for family farmers in diffuse communities, especially the vulnerability of agricultural production to salinity problems.

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Modeling Resource Availability in Dynamic Grid Computing

Modeling Resource Availability in Dynamic Grid Computing

Each provider in the grid is an object with two fields: arrivalTime learns this provider’s arrival time to the market (i.e., the stating uptime interval), and departTime memorizes its departure time (i.e., the starting downtime interval). The first action of each arrival event schedules the next departure event in a random number of time steps, generated from exponential distribution ”ED” with rate λ (i.e., mean = 1/λ). Then, the normal service can be submitted. In other word, the provider is ready to open a new auction and call interested buyers. On the other hand, when the Departure event occurs, the provider is removed from the current list of participated providers, and schedules the arrivals time step in a random-variate generator using Pareto distribution with shape parameter rate α and location parameter β. Here, we should say that the provider is prone to failure, in case of the resource was not free during the departure event. As a conse- quence, the provider must compensate the consumer for the job failure. For the analysis of the departed providers under exponential distribution ”ED”scenario we change the value of the scale parameter λ = {0.005, 0.01, 0.015} for each simulation respectively. For Pareto distribution ”PD” scenario we change the scale paremeter α = {0.515, 1.03, 1.545} for each simulation as well. Figure 2 exhibit the effect of scale parameters upon the departed providers. We can see that there is a significant difference among different scale values. The overall trend is that the number of departed providers increases as the scale values (λ and α) increase as indicated in figures (2a) and (2b) respectively. We also notice that the number of departed provider is fairly modest as λ get smaller. The impact of churn on the job failure is apparent as shown in the graph 3. It indicates the number of jobs that need to be resubmitted because of failure at least once or more. The difference between the different scale values cases is as one would expect: smaller scale values means shorter uptimes and leads to more jobs resubmissions.
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The role of uncertainty in supply chains under dynamic modeling

The role of uncertainty in supply chains under dynamic modeling

Holding cost (UC_S in Fig. 10) influences the NPV of supply if stock-out costs are of a limited amount ( ≤0.25 €/unit*time)). If the product matches the limited amount of obsolescence and shortage cost does not occur, in a stable and trusty market, the demand rate does not influence the position of OPP that could be maintained at any echelon of supply if marginal changes in optimization performances are accepted. In stable markets (with no correlation between events, this permits reference to the first quartile of cumulative standard deviation of demand), OPP does not influence global revenues if products have limited obsolescence (under the first quartile in cost per unit per time). The stability of the market is not relevant if the product requires high costs in maintaining and stock-out probability is limited. Here, OPP requires to be settled at the lowest level of supply (i.e., Retailers). Fixed warehousing costs with limited holding cost (0.25 ≤ Wh_c ≤0.5) in a small or medium market allows OPP fluctuations even though an optimal collocation of the pull/push hinge is admitted. In this case, the position of OPP moves forward from the Factory to the Retailer in a stable (first quartile in demand variation) market with limited unit stock-out cost. In cooperative supplies handling a huge amount of products (cumulative demand rate near 10 4 unit/week—medium enterprises), there exists optimum OPP. Volatility in demand influences Warehouse costs while preferring batch orders although seasonality in demand occurs. Here, pull supplies, under conditions of unstable market and relevant shortage cost per unit per time (i.e., OPP in the Factory), is required for the optimisation of overall performances. A pure push strategy in supply is required whenever stock-out cost is of a limited amount of unit per time (first quartile). OPP moves backwards as uncertainty in market increases. Here, the Warehouse cost influences the OPP location: the Retailer is preferable over the Factory location.
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Dynamic Impact Test of the Railing with Dissipative Elements

Dynamic Impact Test of the Railing with Dissipative Elements

Standards and methodologies for the design, construction and upgrading of roads and the location of buildings and installations in their area should ensure, in the conditions of high tech and economic efficiency, the judicious combination of public roads and exploitation, achieving a uniform road network, storage and use of existing road network upgrading saving and rational use of land, increasing the efficiency and safety of road transport.

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Modeling and linear parametervarying  of a twotank system

Modeling and linear parametervarying of a twotank system

Another strong add in the LPV system identification was the introduction of the least squares support vector machines (LS-SVM) from the machine learning field in (TÓTH et al., 2011). The introduction of LS-SVMs in the LPV framework was very important, mainly due to the learning appeal and the use of Kernels that can learn the underlying parameter’s dependency with the scheduling variable. This was a huge advantage over the general methods in regression form, in which one must select an appropriate basis function to define the underlying relationship between regressors and the scheduling variable. As the kernel method became an interesting feature in LPV system identification in IO setting, the subspace approach made important steps toward regularization techniques, such as in (GEBRAAD et al., 2011), where a novel approach using nuclear norm regularization is proposed in the LPV subspace approach. The purpose remained quite the same which is to cope with the curse of dimensionality in data matrices. In fact, the use of kernels dominated the first half of the decade and it is still an active area of research in the LPV identification literature. The LPV LS-SVM identification is investigated under general noise conditions in (LAURAIN et al., 2012). A common assumption in most of the works presented so far is that the scheduling variable is a free noise measured signal. In (LOPES DOS SANTOS et al., 2012) an extension of the algorithm presented in (LOPES DOS SANTOS; RAMOS; MARTINS DE CARVALHO, 2009) is generalized to cope with quasi-stationary scheduling sequences. A separable least squares approach was extended to the LPV case in (LOPES DOS SANTOS et al., 2013). An algorithm that identifies the LPV order in the LS-SVM framework was introduced in (PIGA; TÓTH, 2013). Before that, a study on LPV-ARX order selection had been done in (TÓTH; HJALMARSSON; ROJAS, 2012). The general LS-SVM for the LPV case was extended to cope with noisy scheduling variables in (ABBASI et al., 2014). The separable least squares approach was extended to the LPV LS-SVM framework in (LOPES DOS SANTOS et al., 2014).
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Dynamic modeling and simulation of power transformer maintenance costs

Dynamic modeling and simulation of power transformer maintenance costs

The expected service life of the commercially available CMS is 10 years, and the purchase price is about 10% of the corresponding components purchase price. In the literature, the price and duration of detected faults mostly are ignored, because it is minimal or zero. For safety reasons, it is assumed that the detected defects in the windings and core eliminated in 5 days at a price of 5000 EUR, while on the other components will be eliminated only minor failures. By CMSI of power transformer components enables detection of failures at the earliest stage of development. This increases the intensity of minor and reduces the intensity of major component failures. Reducing the intensity of major failures has resulted in an increase in scale parameter of Weibull's distribution.
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Rev. CEFAC  vol.18 número5

Rev. CEFAC vol.18 número5

A study analyzed the eficacy of two voice treatment programs in 44 dysphonic teachers, divided randomly in three groups, 15 teachers using the sound ield system ChatterVox, 15 teacher in vocal hygiene program, and 14 teachers in control group without treatment. Before and after six weeks period of intervention, the teachers were assessed in acoustic analysis and addressed the Voice Handicap Index (VHI), a self-assessment questionnaire of the dysphonia severity, and one scale of voice and acoustic changes analysis after the treatment. The results showed only the group using ampliication had the lower scores in VHI, decrease in self-perception of general grade of dysphonia, and decrease in acoustic measures jitter and shimmer. The questionnaire investigating the perceived beneits after treatment addressed showed signiicant difference between the group using sound ampliication and the vocal hygiene guidance, and the group with sound ampliication reported more intelligibility of singing and speaking voices, easier to produce voice, and were more adapted to the treatment schedule. The results corroborate with the acoustic indings of the current research, and reinforce the possibility of sound
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Modeling of the Market-Manufacturing System Relationship

Modeling of the Market-Manufacturing System Relationship

Abstract— In order to progress in the present-day complex and unpredictable environment, the company must feature abilities of quick response and favorably reposition itself on the market. Acquisition and preservation of this capacity is the most difficult step for companies as it involves many endogenous and exogenous factors and the process is continuous, dynamic and hardly predictable. The paper goal is a new approach of the manufacturing systems - market assembly, with a view to finding the quantities that characterizes it, the laws that govern it, the relationships that describe it, and on this basis, to design a competitive management system of the assembly as a whole. The approach is general, but the application is focused on the manufacture of mechanical products, in small and medium series, always taking into account the dynamics of the interaction factors such as capital, market and system.
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Adaptive Data Collection Front-End - ADaFE

Adaptive Data Collection Front-End - ADaFE

No entanto novos problemas surgem com essa abordagem. Enquanto os modelos de objectos comuns nos quais a ES se baseia eram a combinação perfeita para as práticas habituais, também eles colocam restrições à velocidade com que se consegue mudar um sistema. O que o ADaFE se propõe a fazer é trabalhar sobre um tipo diferente de modelação de sistemas, designado AOM - Adaptive Object Modeling, tendo em consideração as restrições impostas pelo design para móveis. AOM pode ser considerado um padrão de projecto de software constituído por uma série de padrões mais pequenos direccionados para criar sistemas adaptáveis. Requere a modelação com um nível de abstracção adicional, dividindo os modelos num nível de conhecimento (meta) e outro operacional mais próximo do que os engenheiros de software estão habituados. A necessidade de prever mudanças e aplicar metaprogramação traz alguma complexidade aos sistemas baseados em AOM. Somando isso ao facto de que muitos engenheiros são mais programadores que mode- ladores (especialmente nos mundo dos aparelhos móveis) tende a afastá-los de tais arquitecturas.
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J. Aerosp. Technol. Manag.  vol.4 número2

J. Aerosp. Technol. Manag. vol.4 número2

Abstract: In this paper, we have used the differential evolution to optimize the design of a Micro Air Launch Vehicle and its launch trajectory. Since trajectory design of a launch vehicle requires prior knowledge of the masses and propulsion performance parameters of the Micro Air Launch Vehicle, whereas the vehicle design requires prior knowledge of the required velocity ¨V to insert the required payload into the target orbit, a twostep optimization cycle was adopted. A Micro Air Launch Vehicle was designed to launch a 20kg payload into a 00km circular polar orbit. The preliminary design of the Micro Air Launch Vehicle was conducted given the required ¨V, which was obtained from trajectory optimization, and then applied in mission analysis to obtain the initial masses. These initial masses were used in the vehicle design to get the performance and geometry parameters. The objective function of the Micro Air Launch Vehicle design optimization is to minimize the initial mass under speci¿ed constraints on the insertion orbit. The objective of trajectory optimization is to maximize the payload mass under constraints on orbit speci¿cations and design variables. For the 20kg payload mass, the optimal initial mass is 1267.8 kg and optimal payload is 20.6 kg, which slightly exceeds the mission requirements.
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The Concepts of «System» and «Social System»  in the Modeling of Social Processes

The Concepts of «System» and «Social System» in the Modeling of Social Processes

Парсонсу, социальная система является подсистемой «более общей системы действия, другими составляющими которой являются культурные подсистемы, личностные подсистемы и.. Модели [r]

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J. Braz. Soc. Mech. Sci. & Eng.  vol.29 número3

J. Braz. Soc. Mech. Sci. & Eng. vol.29 número3

This work analyses a real time orbit estimator using the raw navigation solution provided by GPS receivers. The estimation algorithm considers a Kalman filter with a rather simple orbit dynamic model and random walk modeling of the receiver clock bias and drift. Using the Topex/Poseidon satellite as test bed, characteristics of model truncation, sampling rates and degradation of the GPS receiver (Selective Availability) were analysed.

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Denise Schmidt1 ; Vilson J Gabriel1 ; Braulio O Caron1 ; Velci Q Souza2 ; Ricardo Boscaini1 ; Renes R Pinheiro1 ; Carine Cocco1

Denise Schmidt1 ; Vilson J Gabriel1 ; Braulio O Caron1 ; Velci Q Souza2 ; Ricardo Boscaini1 ; Renes R Pinheiro1 ; Carine Cocco1

The aim of this study was to evaluate the influence of different profile colors based on nutrient flux on microclimate, growth and yield of four rocket cultivars. The experiment was conducted during four months in a protected environment in the NLT system, which consisted of benches composed of eight hydroponic profiles for the plants conduction. The treatments were arranged in a 4x2x2 factorial design, with four cultivars (Cultivada, Folha Larga, Rococo and Runway), two color profiles (black and white) and two growing seasons (autumn and winter). The experiments were conducted in a randomized block design with three replications. The evaluations were realized on every four days, throughout the growth period. Leaves fresh and dry mass, stems and roots, plant height, leaf number and leaf area index were evaluated. The different color profiles resulted in variations on crop growth and production due to the thermal changes within the hydroponic profile. The greatest growth and increased productivity were obtained from plants cultivated in white growing channels during the autumn. The cultivars Cultivada, Folha Larga and Rococo have similar performance, better than ‘Runway’.
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