Showing papers by "College of Engineering, Pune published in 2010"

Extended-State-Observer-Based Control of Flexible-Joint System With Experimental Validation

Abstract: In this paper, a feedback linearization (FL)-based control law made implementable using an extended state observer (ESO) is proposed for the trajectory tracking control of a flexible-joint robotic system. The FL-based controller cannot be implemented unless the full transformed state vector is available. The design also requires exact knowledge of the system model making the controller performance sensitive to uncertainties. To address these issues, an ESO is designed, which estimates the state vector, as well as the uncertainties in an integrated manner. The FL controller uses the states estimated by ESO, and the effect of uncertainties is compensated by augmenting the FL controller with the ESO-estimated uncertainties. The closed-loop stability of the system under the proposed observer-controller structure is established. The effectiveness of the ESO in the estimation of the states and uncertainties and the effectiveness of the FL + ESO controller in tracking are demonstrated through simulations. Lastly, the efficacy of the proposed approach is validated through experimentation on Quanser's flexible-joint module.

Performance Analysis of MUSIC and ESPRIT DOA Estimation Algorithms for Adaptive Array Smart Antenna in Mobile Communication

Abstract: Adaptive array smart antenna involves the array processing to manipulate the signals induced on various antenna elements in such way that the main beam directing towards the desired signal and forming the nulls towards the interferers. Such smart antennas are widely used in wireless mobile communications as they can increase the channel capacity and coverage range. In adaptive array smart antenna, to locate the desired signal, various direction of arrival (DOA) estimation algorithms are used. This paper investigates and compares MUSIC and ESPRIT, DOA estimation algorithms which are widely used in the design of smart antenna system. MUSIC and ESPRIT algorithms provide high angular resolution and hence they are explored much in detail by varying various parameters of smart antenna system. However simulation in this paper shows that MUSIC algorithm is highly accurate and stable and provides high angular resolution compared to ESPRIT and hence MUSIC algorithm can be widely used in mobile communication to estimate the DOA of the arriving signals.

Artificial neural network model in surface modification by EDM using tungsten–copper powder metallurgy sintered electrodes

Abstract: Electro-discharge machining (EDM) is a widely accepted nontraditional machining process used mostly for machining materials difficult to machine by conventional shearing process. Surface modification by powder metallurgy sintered tools is an uncommon aspect of EDM. Of late, it is being explored by many researchers. In the present paper, attempts have been made to model the surface modification phenomenon by EDM with artificial neural networks. Two output measures, material transfer rate and average layer thickness, have been correlated with different process parameters and presented in the form of plots. The predicted results are matching well with the experimental results.

Learning style recognition using Artificial Neural Network for adaptive user interface in e-learning

Abstract: Traditionally e-learning systems are emphasized on the online content generation and most of them fail in considering the requirements and learning styles of end user, while representing it. Therefore, appears the need for adaptation to the user's learning behavior. Adaptive e-learning refers to an educational system that understands the learning content and the user interface according to pedagogical aspects. End users have unique ways of learning which may directly and indirectly affect on the learning process and its outcome. In order to implement effective and efficient e-learning, the system should be capable not only in adapting the content of course to the individual characteristics of students but also concentrate on the adaptive user interface according to students' requirements. In this paper, at initial stage we are presenting an approach to recognize the learning styles of individual student according to the actions or navigations that he or she has performed on an e-learning application. This recognition technique is based on Machine Learning algorithm called Artificial Neural Networks and Web Usage Mining.

Surface modification of C40 steel using WC-Cu P/M green compact electrodes in EDM

Abstract: This study deals with surface modification of C-40 grade steel using P/M (powder metallurgy) green compacts of WC?Cu mixture as the EDM tool during a die sinking operation in hydrocarbon dielectric fluid. An L8 Taguchi array is used to investigate the process by varying tool parameters like composition and compaction pressure and EDM operating parameters like polarity, peak-current and pulse-duration. An optimal condition, for getting a uniform layer over the surface, is achieved using OEC (overall evaluation criteria). At the optimum condition, a layer thickness of 48.9μm and an increase in hardness up to 1632Hv are achieved.

Noise Estimation and Noise Removal Techniques for Speech Recognition in Adverse Environment

Abstract: Noise is ubiquitous in almost all acoustic environments. The speech signal, that is recorded by a microphone is generally infected by noise originating from various sources. Such contamination can change the characteristics of the speech signals and degrade the speech quality and intelligibility, thereby causing significant harm to human-to-machine communication systems.

Current differential protection of transmission line using the moving window averaging technique

Abstract: We propose a new approach to current differential protection of transmission lines. In this approach, we transform the instantaneous line current(s) by using a moving window averaging technique. If the time span of moving window is equal to one-cycle time, then the steady-state value of the transformed current is zero for a periodic signal which is composed of fundamental and harmonic frequencies. Signal distortions (e.g., a fault) cause the transformed currents to deviate from the nominal zero value. This permits the development of a sensitive, secure, fast, and yet simple current differential protection scheme. The scheme can be applied in toto to series-compensated transmission lines. Results on a four-machine ten-bus system and comparative evaluation with state-of-the-art methods brings out promise of the proposed method.

Adaptive current differential protection schemes for transmission-line protection

Abstract: Throughout the history of power system protection, researchers have strived to increase sensitivity and speed of apparatus protection systems without compromising security. With the significant technological advances in wide-area measurement systems, for transmission system protection, current differential protection scheme outscores alternatives like overcurrent and distance protection schemes. Therefore, in this paper, we address this challenge by proposing a methodology for adaptive control of the restraining region in a current differential plane. First an error analysis of conventional phasor approach for current differential protection is provided using the concept of dynamic phasor. Subsequently, we extend the methodology for protection of series compensated transmission lines. Finally, we also evaluate the speed versus accuracy conflict using phasorlets. Electromagnetic Transient Program simulations are used to substantiate the claims. The results demonstrate the utility of the proposed approach.

Design of a discrete-time sliding mode controller for a magnetic levitation system using multirate output feedback

Abstract: The advent of highly efficient and superior digital computers and microprocessors in controller implementation has led to a significant interest in the field of discrete time controller design Design of a discrete time sliding mode controller for a magnetic levitation system based on a multirate output feedback strategy is presented The control objective is to precisely stabilize the position of a ferromagnetic ball above the ground by levitating it against the force of gravity using an electromagnet For this application, we designed a discrete time sliding mode controller using the equivalent discrete time reaching law Furthermore, we developed a new formulation on discrete time sliding mode control using multirate output feedback for this application, guaranteeing a system response close to that obtained through implementation of a continuous time sliding mode control Simulation results show that for a magnetic levitation system the later, multirate output feedback based discrete time sliding mode controller is more robust than the former, discrete time sliding mode controller Also, the phenomenon of chattering present in practical continuous time sliding mode controllers is significantly reduced in the discrete time counterparts

Adaptive Neuro-fuzzy Inference System with Subtractive Clustering: A Model to Predict Fiber and Yarn Relationship:

Abstract: The spinning process is an important process in the Textile Industry. The yarn (output) coming out of the spinning process has a unique relationship with the input fibers. The input and output prop...

A fast and light classifier for data streams

Abstract: Analysis of data streams is becoming a key area of data mining research, as the number of applications demanding such processing increases. Modern information technology allows information to be collected at a far greater rate than ever before. Machine learning offers promise of a solution, but the field mainly focuses on achieving high accuracy when data supply is limited. While this has created sophisticated classification algorithms, many do not cope with increasing data set size. When the data set size gets to a point where it could be considered to represent a continuous supply or data stream then incremental classification algorithms are required. When tackling with non-stationary concepts, ensemble of classifiers has several advantages over single classifier methods. They are easy to scale and parallelize, they can adapt to change quickly by pruning underperforming parts of the ensemble and they therefore usually generate more accurate concept descriptions and efficient results. But the effectiveness of an algorithm cannot simply be assessed by accuracy alone. Consideration needs to be given to the memory available to the algorithm and the speed at which data is processed in terms of both the time taken to predict the class of a new data sample and the time taken to include this sample in an incrementally updated classification model. This paper proposes a fast and light classifier for data stream classification.

A Novel Multi-feature Multi-classifier Scheme for Unconstrained Handwritten Devanagari Character Recognition

Abstract: This paper presents a novel approach for recognition of unconstrained handwritten Marathi characters. The recognition is carried out using multistage feature extraction and classification scheme. The initial stages of feature extraction are based upon the structural features and the classification of the characters is done according to their parameters. The final stage of feature extraction employs Radon transform and Euclidean distance transform and applied to two separate feed forward back propagation neural networks. The hybrid classifier at the final stage takes the input from two neural network classifiers and template matching classifier and decides the final output based on maximum voting rule. This multistage feature extraction and classification scheme improves the recognition accuracy over individual classifiers considerably. The recognition rate achieved from the proposed method is 95.40%.

Material based characterization of aqueous metal oxide based supercapacitors

Abstract: Supercapacitors (SC) / Electro Chemical Double Layer Capacitor (EDLC) is yet to experience widespread use. Recently, advances have been made in improving both energy and power density. Due to their limited power and energy capabilities, they saw use in applications such as memory backups. New applications in the area of FCV, EV, EHV, space, military, automotive subsystems and industrial automation are being attempted at an increasing rate. Its use in electronic devices like mobiles, Laptops and communication systems is gaining momentum. Supercapacitor is mainly a pulse power device even though it is seen as a replacement to battery in low power applications. In pulse power, the width of pulse, stability, repetition rate along with commercial aspects like cost, volume, weight and life requires attention. Aqueous metal oxide based supercapacitors are more compatible with battery. Material based models which are useful in fabrication of electrode are presented for their comparative study.

Temperature Estimation of Visible Heat Sources by Digital Photography and Image Processing

Abstract: This paper proposes a novel noncontact temperature measurement technique using a consumer-grade digital still camera. The images of various visible heat sources are captured. Using color image segmentation, source zones are identified. The actual temperature is measured by placing a miniature thermocouple in each zone. The color temperature correlation is established by applying various analytical techniques. Different equations are formulated for different zones observing color dominance in the respective zone. The results indicate that the image-based measurements agree with the corresponding contact measurements within an error range of about ±5% for most of the sources. The technique is successfully used for measuring the temperature distribution of different industrial applications, like muffle furnace, salt bath furnace, induction furnace, etc.

Novel integrated development environment for implementing PLC on FPGA by converting ladder diagram to synthesizable VHDL code

Abstract: Programmable logic controllers (PLCs) are the universally accepted automation components in industrial control. IEC61131–3 standard was developed to unify textual and graphical ways of describing the control specification for PLCs; ladder diagram being one such control specifications. However, PLCs available in the market as on today are vendor specific and replacement of PLC of one vendor in a process equipment by PLC of another vendor is not possible due to lack of standardization among EDA tools from PLC vendors. Secondly, heart of PLCs is a sequential processor which cannot execute parallel rungs of ladder diagram concurrently. Perhaps this aspect did not pose any problem so far due to large response times associated with industrial processes. However with introduction of high speed MEMS sensors along with increased control complexity, the need for high speed PLCs has been spelt out. Further, the safety features of control system are now expected to be integral part of ladder control specification. Field Programmable Gate Arrays (FPGAs) have better portability support, ability to support implementation of concurrent logic and security aspects. They have been mentioned in the literature as prospective programmable devices to implement control logic of PLCs. However, utilization of FPGAs for implementing control specification demands development of integrated environment to convert ladder logic as per IEC61131–3 to HDL. This HDL specification further can be ported to any of the standard FPGA development environments. It is seen through literature that not enough efforts have been focused on developing such integrated environment. This paper focuses on the details of such environment being developed by authors to convert IEC-61131–3 control specification standard to VHDL for direct synthesis.

Higher-order nonlinear electromechanical effects in wurtzite GaN/AlN quantum dots

Abstract: As we demonstrated earlier, conventional mathematical models based on linear approximations may be inadequate in the analysis of properties of low-dimensional nanostructures and band structure calculations. In this work, a general three-dimensional axisymmetric coupled electromechanical model accounting for lattice mismatch, spontaneous polarization and higher-order nonlinear electrostriction effects has been applied to analyze properties of GaN/AlN quantum dots coupled with wetting layer. The generalized model that accounts for five independent electrostriction coefficients has been solved numerically via a finite-element implementation. The results, exemplified for truncated conical GaN/AlN quantum dots, demonstrate that the effect of nonlinear electrostriction in GaN/AlN nanoheterostructure quantum dots could be significant. In particular, the influence of nonlinear electromechanical effects on optoelectronic properties is highlighted by the results on band structure calculations based on a multiband effective mass theory.

Synthesis of nanosized barium titanate/epoxy resin composites and measurement of microwave absorption

Abstract: Barium titanate/epoxy resin composites have been synthesized and tested for microwave absorption/transmission. Nanocrystalline barium titanate (BaTiO3 or BT) was synthesized by the hydrothermal method and the composites of BT/epoxy resin were fabricated as thin solid slabs of four different weight ratios. BT was obtained in the cubic phase with an average particle size of 21 nm, deduced from the X-ray diffraction data. The reflection loss (RL) and transmission loss (TL) of the composite materials were measured by the reflection/transmission method using a vector network analyser R&S: ZVA40, in the frequency range 8·0–18·5 GHz (X and Ku-bands). The RL was found to be better than −10 dB over wide frequency bands. The higher RL for lower concentration of BT could be due to increase in impedance matching effects. Low TL values indicate that the absorption by BT is quite low. This could be due to formation of BT in the cubic paraelectric phase.

Subjective and Spectrogram Analysis of Speech Synthesizer for Marathi TTS Using Concatenative Synthesis

Abstract: Paper describe the TTS system using Concatenative synthesis techniques for Marathi language with unit selection speech databases and discuss the issues relevant to the development of a Marathi speech synthesizer using different choice of units: words, phonemes, syllables as a database. The most important qualities of a speech synthesis system are naturalness and intelligibility. We Synthesize the Marathi sentences from the text. Performed the subjective evaluations and spectrogram analysis of the synthesized speech. As per the result 81% of speech synthesized by the proposed method was preferred to that by the conventional method, 40 speech sample were synthesized out of the different kinds of data . Naturalness increases with highest value of data. Spectrogram analysis for different words of the sentences with syllables & phonemes as unit.

Detecting power imbalance in multi-cylinder inline diesel engine generator set

Abstract: The main purpose of this paper is to develop the model of fuel injection adjustment for balancing the four stroke six cylinder inline diesel engine coupling generator set by detecting unbalance in operating engine by the frequency analysis of the crankshaft's speed variation. In this work the crankshaft considered to be a rigid body, so that the variation of its angular speed could be directly correlated to the total gas-pressure torque. Actually, the variation of the crankshaft's speed has a complex nature being influenced by the torsional stiffness of the cranks, the mass moments of inertia of the reciprocating and rotating masses and the average speed and load on the engine. Analyzing only the lower harmonic orders (½, 1, and 1½) of the speed variation spectrum can filter out the distortions produced by the dynamic response of the crankshaft. The information carried by these harmonic orders permits to establish correlations between measurements and the average gas pressure torque of the engine, and to detect unbalance and identify faulty cylinders. Detail experimental reading were taken on diesel engine coupling genset on the test bed of Greaves Cotton Ltd Pune, India.

Algorithm for Secured Online Authentication Using CAPTCHA

Abstract: CAPTCHA stands for Completely Automated Public Turing Tests to Tell Computers and Humans Apart. A CAPTCHA is a program that protects websites against bots –automated scripts by generating and grading tests that humans can pass but current computer programs cannot. For example, humans can read distorted text but current computer programs can't. The threats from bots is growing rapidly and also increasing in technical sophistication causing various types of attacks. These attacks are affecting social aspects of human beings. Human being or legitimate users are cheated by false requests disturbing their social life. This paper aims to provide secured authentification by verifying strength of CAPTCHA. The strength of CAPTCHA can be verified by solving it. The CAPTCHA solving has mainly three steps such as preprocessing, segmentation and character recognition. The input distorted image of CAPTCHA is passed through preprocessing module which removes noise and gives raw image which is then segmented. These segmented characters are recognized using pattern-matching technique achieving 88% accuracy. The result shows that this algorithm provides secured social relevance to avail free Internet services and in turn improve usability of well-claimed CAPTCHA.

Intelligent controllers applied to SVM-DTC based induction motor drives: A comparative study

Abstract: Direct Torque Control (DTC) has been popular amongst researchers in last few decades. Dynamic and ripple-free control of electric drive has become possible using Space Vector Modulation (SVM) based DTC. Owing the simple structure and wide operating range, PI controllers are used to control torque and flux independently in case of SVM-DTC. But these controllers are less adaptive in situations of change in load, uncertain model or nonlinearities. This demands either for tuning of PI controllers or altogether different control algorithm. This paper presents a comparative study of three algorithms applied to SVM-DTC. 1. Fuzzy Inference System (FIS) tuned PI control algorithm 2. Variable Structure Control based Sliding Mode Control (SMC) algorithm 3. Fuzzy-Sliding Mode Control (FSMC) algorithm. These design strategies are then compared for normal as well as dynamic operating conditions and their capability to handle parameter variations, disturbance rejection is studied. Also a term Integral Time Absolute Error (ITAE) is used as a performance measure to present numerical comparison of the algorithms.

Multi objective optimization of planetary gear train

Abstract: In present work, multi-objective optimization of multi-stage planetary gear train is done. Optimization of multi-stage speed reducer is difficult due to involvement of integer variables. Minimizing surface fatigue life factor and minimization of volume of gear box are two conflicting objective functions under consideration. Two methods, one classical (SQP) and other nontraditional (NSGA-II) have been used for analysis to satisfy strength and other geometric criteria. Previous work is concentrated on optimization of spur or helical gears. This work is an extension to earlier work in a sense that planetary gear train with reduced speed involves more geometric constraints.

Design of firmware update system of RT-Middleware for embedded system

Abstract: In this paper, we propose the design of firmware (FW) update system for RTC-CANopen, including system structure and FW update algorithm. RTC-CANopen enables embedded and robotic systems to use existing CANopen device easily. We developed update algorithm and system based on the CANopen software update standard. Thus, our proposed system is able to support standard CANopen devices. By accomplishing our research, we can easily maintain the FW of embedded system as well as robotic system adopting RTC-CANopen.

An Intelligent System for Hepatitis B Disease Diagnosis

Abstract: In spite of all standardization efforts, medical diagnosis is still considered as an art owing to its uncertainty that today’s computing machinery cannot cope with. This research is performed for the search of substitutes to the resolution of complex medical diagnosis where human knowledge is detained in a general fashion. Artificial neural network algorithms provide a reasonably high-quality solution for medical problems and this paper is concerned with the diagnosis of hepatitis B. In this paper, we present an intelligent system for hepatitis B diagnosis using a standard feed-forward network with multilayer perceptron (MLP) structure and back propagation algorithm. The results obtained reveal that neural networks can be successfully used for the diagnosis of hepatitis B. Also, a comparative analysis is performed with a number of other knowledge-based systems designed for hepatitis B diagnosis, to prove the effectiveness of the proposed intelligent system based on MLP.

Analysis and design of ICU Knowledge Management System (IKMS) for Indian environment with usability perspective

Abstract: In this paper, we have proposed ICU Knowledge Management System (IKMS). Intensive Care Unit (ICU) is specialty-nursing unit for critical patients. An IKMS presented in this paper is designed with usability perspective in Indian ICU environment. This design is based on a study about the scope of ergonomic design and usability for ICU through the fieldwork at various hospitals in India. The feedback received from ICU staff, observations about ICU facilities and usage of medical equipment have been vital inputs in design of IKMS. Our research highlights the need to use such knowledge management system supported by ICU knowledgebase to assess the quality standard focusing on ergonomic design and usability of ICU. We feel that hospital administrators, academicians, researchers and equipment manufacturers will also benefit from this system. Therefore, this research work with Indian ICUs and related IKMS will prove to be extremely helpful in assessing and improving the quality and usability standards of ICUs.

A Comparative Study of Life Cycle Cost Analysis of Pumps

Abstract: For a product to be commercially successful and increasingly competitive in this global market place, it is imperative that engineers must understand and design for each phase in the life cycle of a product. The life cycle cost (LCC) of any piece of equipment, such as a pump represents the total cost to procure, install, operate, maintain and dispose of that equipment. For sustainment dominated products or systems, the lifetime energy and/or maintenance costs dominate the life cycle cost as compared to its initial cost. The initial cost is only a fraction of the life cycle cost. Therefore, a due consideration to the life cycle cost issues at product design stage is quite essential. The LCC analysis is recommended only at the product design phase, as up to 80% of product LCC is committed at this phase. A better understanding of the cost components that make up the life cycle cost is expected to provide the product designers an opportunity to considerably reduce product LCC. In this paper, a methodology for LCC analysis based on reliability and maintainability principles has been applied to three different pumps and the results of analysis have been compared. For analysis purpose, two pumps have been selected from the literature and the data available therein is utilized. The third pump is selected from a well known pump manufacturer from India and the required data is obtained directly from the manufacturer. To model the maintenance and repair cost the concept of expected number of failures in a given time interval has been applied. The maintenance and repair cost is estimated for two different maintenance and repair strategies, the renewal/replacement upon failure strategy and minimal repair upon failure strategy and under the conditions of constant failure rate (exponential distribution) in first case and increasing failure rate (Weibull distribution) in the second case. The results obtained have been presented and compared at the end. The methodology presented in this paper is expected to help the pump designers to estimate and compare the life cycle cost of their different design alternatives.Copyright © 2010 by ASME

Performance of a disc brake friction material

Abstract: The friction materials used in brakes are required to provide a stable coefficient of friction and a lower wear rate at various operating speeds, pressures, temperatures and environmental conditions. These friction materials must also be compatible with the rotor material in order to reduce its extensive wear, vibration and noise during braking. All of these requirements need to be achieved at a reasonable cost and minimum environmental load. Selection of the material is often based on experience or a trial and error method. This paper deals with the performance of a disc brake friction material for a vehicle. There are different friction performance properties such as base line check, average coefficient of friction. The physical properties are studied according to Indian standards. The results are discussed and correlated to the observed friction phenomenon.

Improvement in thermal, mechanical and water resistance properties of epoxy/glass particulate composites

Abstract: Glass particulate reinforced epoxy matrix composites containing 0 to 32 vol% glass particulate were prepared by mechanical mixing followed by hot pressing. For this, lead borosilicate glass of composition 75PbO, 7B2O3, 14SiO2, 3Al2O3, and 1P2O3 (by wt%) was prepared by melting the requisite ingredient at 900 °C and quenching the melt to produce glass frit. Prepared composites were characterized by various characterization techniques. Scanning electron microscope showed good dispersion of glass particulates in the matrix. However, some porosity was found at higher glass content. Vickers hardness increased by 4 folds for 32 vol% composite. It correlates well a modified rule of mixtures with strengthening efficiency parameter (β) equal to 0.25. The coefficient of thermal expansion (CTE) decreased by 40 % for 32 vol% composite. Experimental CTE is slightly lower than that of theoretical CTE due to the good adhesion between the epoxy and the glass particulates. The moisture absorption of the composites measured at 95 °C follows Fickian diffusion. The parabolic rate constant decreased from 0.20 to 0.022 cm−2 h−1/2 as the glass content increased from 0 to 32 vol%. The 2 h boiling water test showed that the moisture absorption rate of composite decreased by 8 folds compared to pure epoxy.