Faculty Publications
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Publications by NITK Faculty
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Item Development of Guided Autonomous Navigation for Indoor Material Handling Applications(Springer, 2018) Geetha Jayaprakash, A.; Bairampalli, S.; Desai, V.; Bhat, R.In recent past emphasis on material handling requirements in industry has gone up considerably and in particular several researchers have attempted to improve the indoor material handling. In this paper an autonomous navigation system is implemented on a trolley for applications intending to move the trolley along a predefined path without human operator assistance. The trolley operates in two modes: Learning mode and Autonomous mode. In the learning mode the operator has to manually move the trolley along a path, it has to follow autonomously when the autonomous mode is activated. © Springer International Publishing AG 2018.Item Performance and emission studies on the effect of injection timing and diesel replacement on a 4-S LPG-Diesel Dual-Fuel Engine(SAE International, 2003) Sudhir, C.V.; Desai, V.; Kumar, S.Y.; Mohanan, P.Reducing the emissions and fuel consumption are no longer future goals; instead they are the demands of the day. People are concerned about rising fuel costs and effects of emissions on the environment. Diesel engines are the major contributors to the increased levels of pollutants. In the present work an attempt is made for effective utilization of diesel engine with reduced fuel consumption, smoke density and NOx emissions. This is achieved by some minor modifications in diesel engine so as to run it as LPG-Diesel Dual-fuel engine with LPG (Liquefied Petroleum Gas) (70% Butane + 30% Propane) induction at air intake. The important aspect of LPG-Diesel dual-fuel engine is that, it shows significant reduction in smoke density, NOx emission and improved brake thermal efficiency with reduced energy consumption. An existing 4-S, single cylinder, naturally aspirated, water-cooled, direct injection, C.I. engine test rig was used for the experimental purpose. With proper instrumentation the tests were conducted under various LPG flow rates, loads, and injection timings. The influence of the diesel replacement by LPG on smoke density, brake specific energy consumption and brake thermal efficiency was studied. The optimal diesel replacement pertaining to the maximum allowable LPG flow limits could be assessed with these experiments. The influence of the injection timing variation on the engine performance and smoke density was analyzed form the experimental results. It was observed that beyond half load operation of the dual-fuel engine, thermal efficiency increased with diesel replacement, and at full load up to 4% improvement was observed compared to full diesel operation. There was drastic reduction in NOx emissions (up to40- 60 %) for the entire load range, except near full load where NOx increased (by38%) beyond full diesel value at normal injection timing. At full load reduction in smoke density up to 40% to 60% was observed compared to full diesel operation. At advance injection timing of 30°btdc the performance of the dual fuel engine was better with lower smoke density, while the NOx emission was found to be higher. Copyright © 2003 SAE International.Item Studies on influence of injection timing and diesel replacement on LPG-diesel dual-fuel engine(2003) Sudhir, C.V.; Desai, V.; Suresh Kumar, Y.; Mohanan, P.Reducing the emissions and fuel consumption for IC engines are no longer the future goals; instead they are the demands of today. People are concerned about rising fuel costs and effects of emissions on the environment. The major contributor for the increased levels of pollutants is the Diesel engines. Diesel engine finds application in almost in all fields, including transportation sector such as buses, trucks, railway engines, etc. and in industries as power generating units. In the present work an attempt is made for effective utilization of diesel engine aiming for reduction in fuel consumption and smoke density. This is achieved by some minor modifications in diesel engine, so as to run the existing diesel engine as a LPG-Diesel dual-fuel engine with LPG (Liquefied Petroleum Gas) induction at air intake. The important aspect of LPG-Diesel dual-fuel engine is that it shows significant reduction in smoke density and improved brake thermal efficiency with reduced energy consumption. An existing 4-S, single cylinder, naturally aspirated, water-cooled, direct injection, CI engine test rig was used for the experimental purpose. With proper instrumentation the tests were conducted under various LPG flow rates, loads, and injection timings. The influence of the diesel replacement by LPG on smoke density, brake specific energy consumption and brake thermal efficiency were studied. The optimal diesel replacement pertaining to the maximum allowable LPG gas flow limits could be assessed with these experiments. The influence of the injection timing variation on the engine performance and smoke density were analyzed form the experimental results. It was also observed that beyond half load operation of the dual-fuel engine, the brake thermal efficiency increases with diesel replacement, and at full load up to 4% improvement was observed compared to full diesel operation. At full load reduction in smoke density up to 25-36% was observed compared to full diesel operation. At advance injection timing of 30°btdc the performance was better with lower emissions compared to normal and retarded injection timings. Copyright © 2003 by ASME.Item Studies on influence of injection timing and Diesel replacement on LPG-Diesel dual-fuel engine(2003) Sudhir, C.V.; Desai, V.; Suresh Kumar, Y.; Mohanan, P.Reducing the emissions and fuel consumption for IC engines are no longer the future goals; instead they are the demands of today. People are concerned about rising fuel costs and effects of emissions on the environment. The major contributor for the increased levels of pollutants is the Diesel engines. Diesel engine finds application in almost in all fields, including transportation sector such as buses, trucks, railway engines, etc. and in industries as power generating units. In the present work an attempt is made for effective utilization of diesel engine aiming for reduction in fuel consumption and smoke density. This is achieved by some minor modifications in diesel engine, so as to run the existing diesel engine as a LPG-Diesel dual-fuel engine with LPG (Liquefied Petroleum Gas) induction at air intake. The important aspect of LPG-Diesel dual-fuel engine is that it shows significant reduction in smoke density and improved brake thermal efficiency with reduced energy consumption. An existing 4-S, single cylinder, naturally aspirated, water-cooled, direct injection, CI engine test rig was used for the experimental purpose. With proper instrumentation the tests were conducted under various LPG flow rates, loads, and injection timings. The influence of the diesel replacement by LPG on smoke density, brake specific energy consumption and brake thermal efficiency were studied. The optimal diesel replacement pertaining to the maximum allowable LPG gas flow limits could be assessed with these experiments. The influence of the injection timing variation on the engine performance and smoke density were analyzed form the experimental results. It was also observed that beyond half load operation of the dual-fuel engine, the brake thermal efficiency increases with diesel replacement, and at full load up to 4% improvement was observed compared to full diesel operation. At full load reduction in smoke density up to 25-36% was observed compared to full diesel operation. At advance injection timing of 30°btdc the performance was better with lower emissions compared to normal and retarded injection timings.Item Effect of L/D ratio on Al-Si functionally graded material cast through centrifuge technique(2011) Kiran Aithal, A.S.; Narendranath; Desai, V.; Mukunda, P.G.Functionally Graded Material (FGM) is a class of material wherein the properties and structure are varied intentionally from one side to the other side of the specimen. This paper describes the effect of L/D (Length to Diameter) ratio of the cast on cast Al-Si FGM. The present study uses Al-17%wt Si to cast FGM's. The cast is evaluated for Microstructure and Hardness all along the length of the specimen. Three L/D ratios: 0.5, 1.0, 1.5 were cast using the Centrifuge Technique. The microstructures showed that enrichment of primary Si was largest in 1.5 ratio compared to other two. Hardness value of the cast at the upper and lower region were examined and found that gradient of hardness was more in 1.5 case. High volume percentage of primary Si was nearly 26% in the upper region and a hypoeutectic structure in the lower region. © (2011) Trans Tech Publications.Item Effect of process parameters on centrifugally cast Al-Si FGM(Minerals, Metals and Materials Society 184 Thorn Hill Road Warrendale PA 15086, 2013) Kiran Aithal, K.; Desai, V.; Narendranath, S.; Mukunda, P.G.Functionally Graded Materials (FGM) are such kind of materials wherein the properties and structure are varied from one end of the cast to the other intentionally. Centrifuge technique has been used in this study to produce Al-Si FGMs. Several process parameters determine the microstructure and the distribution of phases in the FG casting. These parameters include the size and initial concentration of alloying element, the centrifugal force, solidification rate, cooling rate. In this work an attempt has been made to produce FGMs using three different process variables such as mold temperature, melt temperature and mold rotational speed, their effect on the structure and properties. For this study Al-17wt%Si is used. From the results it is seen that for a particular melt and mold temperatures by increasing the mold rotation speed enhances the segregation of the Si particles at the one end of the casting. Similarly increasing mold or melt temperature only, increases the segregation.Item System simulation approach for helicopter autopilot(Institute of Electrical and Electronics Engineers Inc., 2014) Jamadagni, C.S.; Chethan, C.U.; Jeppu, Y.V.; Kamble, S.B.; Desai, V.This paper discusses an approach for system simulation of an autopilot system designed for a Bell helicopter model. The flight controls for the helicopter is designed in Matlab/Simulink and the same is visualized in X-Plane flight simulator. The approach involves software in loop simulation method where controls are designed in Matlab/Simulink and the responses are observed on X-Plane plant. The interaction between the Matlab/Simulink and X-Plane is through UDP. A parameter identification of the X-Plane model is carried out from data obtained through UDP. This simulation setup is a good way to learn the intricacies of systems development, plant identification and control. © 2014 IEEE.Item Characterization of aircraft electro hydrostatic actuator using virtual instrumentation(Institute of Electrical and Electronics Engineers Inc., 2015) Sp, K.; Desai, V.; Jeppu, Y.V.In Aerospace industry, implementation of Automated Test System (ATS) at the assembly and manufacturing floor improves characterization accuracy and plays a vital role to substantiate the airworthiness of the aircraft components. It is very useful in realizing high quality standards of aircraft components by virtue of meeting predefined acceptance test criteria. This paper outlines comprehensive design and development of the noise and vibration monitoring system at assembly and manufacturing floor for characterization of Electro Hydrostatic Actuator (EHA) of aircraft using progressions in virtual instrumentation. In aircraft, the flight control actuation system are powered by centralized hydraulic pumps that are driven by the aircraft engine, while the back-up system are driven by electric or ram turbines. Distributed control of electric actuators with integration of control function in Flight Control Computer (FCC) and power electronics is a cost effective approach. EHA does also play a significant role in electrical actuation system, which use distributed electric power drive in driving a hydraulic transmission system. Hence, before integrating with the primary flight control actuation systems in aircraft, EHA's are required to be subjected to noise and vibration characterization, as part of assembly and manufacturing level testing. This method is intended at replacing the monotonous and time consuming traditional method of noise and vibration characterization of the electric actuators at assembly and manufacturing floor and to improve the reliability of the electric actuation components supplied to the aircraft manufacturers. The tests have been performed using a LabVIEW controlled virtual instrument measurement system that monitored the noise and vibration waveform with reference to the tacho signal. © 2014 IEEE.Item System identification for helicopter longitudinal dynamics model - Best practices(Institute of Electrical and Electronics Engineers Inc., 2015) Kamble, S.B.; Desai, V.; Jeppu, Y.V.; PrajnaFor estimation of mathematical model and parameters of a system, the system identification has been widely applied in various domains such as the automatic control, aviation, spaceflight, civil and mechanical engineering, medicine, biology, chemical processes, marine ecology, geology etc. The main aim of this work is to perform preliminary studies to design a control law for helicopter model making it as autopilot. X-plane flight simulator will be used with Matlab wherein the estimated model is imported and simulated for its practical behavior. A longitudinal state-space model of the Puma, SA330 research helicopter is used as a reference model. First, the model is described and with standard reference input test signals, output data set is generated, then this input-output dataset is used for system identification purpose. Both traditional methods such as subspace & prediction-error minimization (PEM) method along with modern ways of identification methods such as neural networks are used. A practical comparison between used identification methods and best suitable type of input for estimation is discussed. © 2015 IEEE.Item Effect of process parameters on centrifugally cast Al-Si FGM(Springer International Publishing, 2016) Kiran Aithal, A.S.; Desai, V.; Narendranath, S.; Mukunda, P.G.Functionally Graded Materials (FGM) are such kind of materials wherein the properties and structure are varied from one end of the cast to the other intentionally. Centrifuge technique has been used in this study to produce Al-Si FGMs. Several process parameters determine the microstructure and the distribution of phases in the FG casting. These parameters include the size and initial concentration of alloying element, the centrifugal force, solidification rate, cooling rate. In this work an attempt has been made to produce FGMs using three different process variables such as mold temperature, melt temperature and mold rotational speed, their effect on the structure and properties. For this study Al-17wt%Si is used. From the results it is seen that for a particular melt and mold temperatures by increasing the mold rotation speed enhances the segregation of the Si particles at the one end of the casting. Similarly increasing mold or melt temperature only, increases the segregation. © The Minerals, Metals & Materials Society 2016.