Faculty Publications
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Item Towards a Domain Specific Modeling Tool for Home Automation Systems(Institute of Electrical and Electronics Engineers Inc., 2020) Patil, P.; Aparna, R.; Chandrasekaran, K.There is a steadily growing market for applications enabling home automation system connectivity to control various applications and home appliances for managing and security purposes. Development of Home Automation (HA) systems involves a lot of complexity resulting from the heterogeneous nature of the system and its need to be able to provide data security and authenticity. The software development life cycle can be shortened if there exists a solution that enables a suitable transformation from design to crude implementation. There are less known integrated framework for HA system development from model to implementation. This solution can be obtained through Model-driven Development. This paper aims to propose a Model-driven Development based solution which models the Home automation domain using meta-modeling technique and a platform-independent Domain-specific Modelling Language (DSML) which can be used for developing platform dependant DSML to achieve automated code generation using a model. The DSML proposed has been validated with the help of a proof of concept, using case studies. This approach can shorten the development duration and more emphasis can be given for the better design of the system. © 2020 IEEE.Item On Feature Models of Home Automation Systems towards Smart Sensing(Institute of Electrical and Electronics Engineers Inc., 2020) Patil, P.; Aparna, R.; Chandrasekaran, K.; Rathnamma, M.V.; Ramana, V.V.The growing need for innovation in software products and an increase in their complexity has demanded an evolution in the software industry in recent years. Domain Analysis assists software developers in understanding the domains leading to significant improvement in their software development. Domain Analysis can be easily carried out using Feature Modelling by identifying the commonalities and variations among attributes of the domain. On the other hand, Home Automation is a developing domain and is now seeing an increase in the number and complexity of products. The heterogeneity of the home automation system elements introduced a lot of complexity to the developers. The commonly observable features and variations arising from HA systems allow us to visualize Home Automation (HA) systems as a Software Product Line (SPL). In this paper, we aim to adopt the Feature Modelling technique for Domain Analysis of the HA system. The efficacy and validity of this approach is evaluated with the help of proof of concepts. © 2020 IEEE.Item Dynamic modeling and performance study of a stand-alone photovoltaic system with battery supplying dynamic load(International Journal of Renewable Energy Research icolak@gazi.edu.tr, 2014) Sabhahit, N.S.; Gaonkar, D.N.; Balan, A.; Patil, P.; Raza, S.A.Autonomous photovoltaic power generation is weather and time dependent which need energy storage to balance generation and demand. This paper presents modeling, simulation and performance study of a stand-alone photovoltaic system along with battery back up. The modeling and simulation of the considered system are accomplished in MATLAB/Simulink environment. The simulation model consists of solar energy source, maximum power point tracking (MPPT) controller, battery energy storage element with controller with associated power electronics converters. A pulse-width-modulated (PWM) threephase inverter controller is developed to regulate three-phase ac bus voltage and frequency. The dynamic load such as a three phase induction motor and DC load are considered to study the performance analysis of the system. Simulation results show that under dynamic and steady state condition the control strategies work satisfactorily to supply power to the load.Item Enhanced PID Controller for Non-Minimum Phase Second Order plus Time Delay System(De Gruyter peter.golla@degruyter.com, 2019) Patil, P.; Sankar Rao, C.A tuning method is developed for the stabilization of the non-minimum phase second order plus time delay systems. It is well known that the presence of positive zeros pose fundamental limitations on the achievable control performance. In the present method, the coefficients of corresponding powers of s, s2 and s3 in the numerator are equated to ?, ? and ?times those of the denominator of the closed-loop system. The method gives three simple linear equations to get the PID parameter. The optimal tuning parameters ?, ? and ?are estimated by minimizing the Integral Time weighted Absolute Error (ITAE) for servo problem using fminsearch MATLAB solver aimed at providing lower maximum sensitivity function and keeping in check with the stability. The performance under model uncertainty is also analysed considering perturbation in one model parameter at a time using Kharitonov's theorem. The closed loop performance of the proposed method is compared with the methods reported in the literature. It is observed that the proposed method successfully stabilizes and improves the performance of the uncertain system under consideration. The simulation results of three case studies show that the proposed method provides enhanced performance for the set-point tracking and disturbance rejection with improved time domain specifications. © 2019 Walter de Gruyter GmbH, Berlin/Boston.Item Hot corrosion behavior of plasma-sprayed NiCrAlY/TiO2 and NiCrAlY/Cr2O3/YSZ cermets coatings on alloy steel(Elsevier B.V., 2021) Reddy, M.; Prasad, C.D.; Patil, P.; Ramesh, M.R.; Nageswara Rao, N.The objective of the Present research work is to evaluate the hot corrosion resistance of plasma-sprayed 70% NiCrAlY+ 30% TiO2 and 70% NiCrAlY+ 25% Cr2O3+5% YSZ coatings on MDN 420 alloy. Hot corrosion tests are carried out under molten salt environment of Na2SO4+60 % V2O5 salt mixture at 700°C for 50 cycles. Each cycle consisting of 1 hour heating in a silicon carbide tubular furnace followed by 20 min of cooling. The thermogravimetric technique was used to determine the kinetics of corrosion. The scanning electron microscopy (SEM), energy dispersive analysis (EDAX), electron probe microanalyser (EPMA) and X-ray diffracton (XRD) techniques were used to evaluate the characterization of coatings with regard to coating bondstrength, thickness, microhardness and porosity. The parabolic rate constants of coated steels are lower when compared to the uncoated substrate. The NiCrAlY+ Cr2O3+YSZ coating is found to be more protective when compared to NiCrAlY+ TiO2 coating. The oxides of Al2O3, NiCr2O4, and Cr2O3 are formed on the outermost layer of the coatings which gives the resistance the coatings to high-temperature corrosion. © 2020Item High-Temperature Oxidation Studies of Plasma-Sprayed NiCrAlY/TiO2 and NiCrAlY/Cr2O3/YSZ Cermet Composite Coatings on MDN-420 Special Steel Alloy(Springer, 2021) Madhu Sudana Reddy, G.; Prasad, C.D.; Shetty, G.; Ramesh, M.R.; Rao, T.N.; Patil, P.The plasma spray process was used to form 70%NiCrAlY + 30%TiO2 and 70%NiCrAlY + 25%Cr2O3 + 5%YSZ cermet coatings on MDN-420 special steel alloy. Cyclic oxidation testing was conducted on coated and uncoated specimens at 700°C under a static air environment. Thermogravimetric analysis was applied to establish the oxidation kinetics. X-ray diffraction (XRD), scanning electron microscopy (SEM)/energy-dispersive x-ray spectroscopy (EDS), and electron probe microanalysis (EPMA) techniques were used to analyze the oxidized products. The NiCrAlY + Cr2O3 + YSZ coating was found to be most resistive when compared with the NiCrAlY + TiO2 coating in the aggressive oxidation environment. Net weight loss was observed for bare MDN-420 alloy due to sputtering. The oxidation resistance of the coatings was due to formation of Cr2O3, NiCr2O4, NiO, and Al2O3 phases. © 2021, ASM International.Item High-temperature oxidation behavior of plasma-sprayed NiCrAlY/TiO2 and NiCrAlY/Cr2O3/YSZ coatings on titanium alloy(Springer Science and Business Media Deutschland GmbH, 2022) Reddy, G.M.S.; Prasad, C.D.; Shetty, G.; Ramesh, M.R.; Rao, T.N.; Patil, P.The 70% NiCrAlY + 30% TiO2 and 70% NiCrAlY + 25% Cr2O3 + 5% YSZ metallic coatings are sprayed on titanium-15 alloy of ASTM B338, Grade 2, by using the plasma spray coating technology. Cyclic oxidation studies are conducted on the uncoated and coated alloys at 700 °C under static air environment. The kinetics of oxidation is studied by using the thermo-gravimetric method. Phase, microstructural, and chemical analysis tests are performed on as-sprayed and oxidized coatings. The coated alloys are found to be more resistant when compared to the uncoated alloys. The NiCrAlY + Cr2O3 + YSZ coating is found to be more protective when compared to NiCrAlY + TiO2 coating. It is concluded that the formation of Cr2O3, NiCr2O4, and Al2O3 is attributed to the development of oxidation resistance in the coatings. © 2022, International Institute of Welding.Item Solid Particle Erosion Behaviour of Plasma-Sprayed (WC–Co)/(Cr3C2–NiCr) Coatings(Springer Science and Business Media Deutschland GmbH, 2022) Reddy, G.M.S.; Ramesh, S.; Anne, G.; Ramesh, M.R.; Rao, T.N.; Patil, P.This study reports the high-temperature erosion behaviour of plasma-sprayed 35% (WC–Co)/65% (Cr3C2–NiCr) coating on MDN-420 alloy. Plasma spray coatings have always played a pivotal role in enabling industries to combat problems of premature degradation of components that operate in harsh environments. (WC–Co) + (Cr3C2–NiCr) coating is investigated for erosion under various laboratory-simulated conditions. Coating surface is characterized by using an optical microscope, scanning electron microscope (SEM), and X-ray diffraction (XRD). Porosity, microhardness, surface roughness, and adhesion strength of the coating are measured. The solid particle erosion test is conducted at the temperatures of 300 °C, 500 °C and 700 °C with the impact angles of 30° and 90° by using Al2O3 as an erodent in the hot air jet erosion testing machine. The optical profilometer is used to evaluate the erosion volume loss of the coated and uncoated samples. It is observed that erosion resistance of the substrate is found to be higher than the coating at the different test temperatures. As the temperature increases, the erosion resistance of the coating is also increased at all the temperatures for both impact angles of 30° and 90°.The eroded coating surface morphology reveals that the generalized behaviour of the coating is ductile in nature. © 2022, The Author(s), under exclusive licence to Springer Nature Switzerland AG.Item Elevated temperature erosion performance of plasma sprayed NiCrAlY/TiO2coating on MDN 420 steel substrate(Institute of Physics, 2022) Reddy G, M.S.; Prasad, C.D.; Patil, P.; Naresh, N.; Ramesh, M.R.The current study deals with the erosion behaviour of a plasma-sprayed 70% NiCrAlY + 30% TiO2 coating on MDN 420 steel substrate at extreme temperatures. The coating was characterized by using an optical microscope, Scanning Electron Microscopy and X-ray diffraction methods. The coating's porosity, microhardness, surface roughness, and adhesion strength were all examined. The solid particle erosion experiments were carried out at temperatures of 300 °C, 500 °C, and 700 °C, with impact angles of 30° and 90°. The tests were conducted by using the alumina as an erodent in the hot air jet erosion testing machine. The erosion volume loss of coated and uncoated samples was measured using an optical profilometer. It is observed that erosion resistance of the coating was found to be more when compared to the substrate for the different test temperatures chosen. As the temperature increases, the erosion resistance of the coating also found increased from 300 °C to 700 °C at both impact angles of 30° and 90°. The morphology of the eroded coating surface reveals that the generalized behaviour of the coating is ductile in nature. © 2022 IOP Publishing Ltd.Item Improved PID controller design for an unstable second order plus time delay non-minimum phase systems(Elsevier B.V., 2022) Patil, P.; Anchan, S.S.; Sankar Rao, C.S.Principally the fundamental limitations for achieving better control performance is caused due to the existence of positive zeros. This study proposes a method to stabilize the unstable non-minimum phase Second Order Plus Time Delay (SOPTD) process. It adopts the Taylor series expansion to produce the equal order of numerator and denominator for the closed loop transfer function. The coefficient of corresponding powers of s, s2 and s3 in numerators are equated to α, β, γ times of the denominator and solved for PID controller setting using multi-objective optimization problems. The stability of the controller is then analysed by minimizing the Integral Time weighted Absolute Error (ITAE) and maximum sensitivity function using MATLAB solvers. The observations from various simulation studies clearly suggests that the proposed method provides significant superior responses when compared with the methods reported. © 2022 The Author(s)