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Gupta R.A.,Indian National Institute of Engineering | Wadhwani A.K.,Madhav Institute of Technology and Science | Kapoor S.R.,Rajasthan Technical University Kota
IEEE Transactions on Energy Conversion | Year: 2011

Even though induction motors are frequently used electromagnetic devices in industries owing to their high reliability, high efficiency, and low maintenance requirements, they are prone to various faults and failures. Most of these faults occurring in the induction motors are perceptible in nascent stages. This averts the inopportune machine failures and helps to adeptly plan the maintenance schedules. Most of the methods used for preprediction of faults in induction motors are based on complicated techniques involving tortuous mathematical analysis. Although the importance and accuracy of these methods cannot be overruled, but a simple method is required as a first stage necessary condition test, which can classify the motor health condition into one of the three broad categories, namely, healthy, fault prone, and critical. This paper discusses a simple method based on symbolic dynamic analysis of stator current samples to detect faults in the induction motors. The experimentation has been performed on a 3Φ, 1.5 kW, 4P, 1440 RPM squirrel cage motor to validate the proposed scheme. The data captured through the laboratory setup have been used to corroborate the proposed symbolic dynamic-based scheme. © 2010 IEEE.

Mittal R.,Rajasthan Technical University Kota
Proceedings of 2015 International Conference on Signal Processing, Computing and Control, ISPCC 2015 | Year: 2015

The robust PI controller and state feedback (Linear Quadratic Regulator) controller are designed to stabilize the dynamic responses of active suspension system with parametric uncertainty followed by road irregularities. To take care about the parametric uncertainties in the suspension system, we design the controller to make robust by polytopic representation of the system. A graphical method is used for computing PI controller parameters for all feasible gain and phase margin specifications. For this purpose, a stability boundary locus in (kp, ki) - plane is used. To achieve the specified gain and phase margin of the system, a gain-phase margin tester is used and stability boundary locus is plotted. The controller gains guarantee the stabilization of the system response with uncertain parameters. The simulation results show the effectiveness of the proposed method. © 2015 IEEE.

Parashar S.K.,Rajasthan Technical University Kota
Journal of Intelligent Material Systems and Structures | Year: 2013

Piezoceramic materials are widely used in solid-state actuators and sensors. Since the shear piezoelectric coupling coefficient d15 is much higher than the other piezoelectric coefficients d31 or d33, the application of shear actuators is of particular interest. Shear-induced vibrations in piezoceramics are more complex to describe mathematically than longitudinal or transverse vibrations. Furthermore, as the complexity of the model increases, the coupling of electrical and mechanical terms precludes the analytical solution of the field equations for all but the simplest case. For a moderately complex piezoceramic model, the implementation of an analytical method to obtain the closed-form solution is very challenging. The use of approximate energy methods, such as the Rayleigh-Ritz method, is explored in this work to obtain the eigenvectors and eigenfrequencies for annular piezoceramic actuators. Series comprising orthogonal polynomial functions, generated using the Gram-Schmidt method, is used in the Rayleigh-Ritz method to formulate the linear eigenvalue problem. The advantage of the presented methodology lies in its adaptability for software implementation, which reduces the efforts to obtain fairly accurate results for more complex piezoceramic structures in future. The efficacy of the presented approximate method is assessed by comparing the results with the experiments. © The Author(s) 2013.

Singh G.,Rajasthan Technical University Kota | Kumar M.,Rajasthan Technical University Kota
Proceedings - International Conference on Communication Systems and Network Technologies, CSNT 2012 | Year: 2012

In this paper, a novel frequency reconfigurable antenna design and development is proposed for wireless devices. In the proposed design, a rectangular patch antenna with square slot using two PIN diodes at the centre frequency 10 GHz was designed and simulated frequency reconfiguration is achieved in the frequency range of 10-10.5 GHz and the measured results shows the same effect in the frequency range of 10.216-10.552 GHz. The frequency reconfiguration is carried out by switching the diodes on/off states. In the fabricated structure of proposed geometry the diodes are replaced by micro strip line for on-state as an ideal case. The antenna is designed on FR4 substrate (ε r= 4.54) of thickness (H) 1.6 mm. The proposed structure was simulated by using the electromagnetic (EM) simulation software. The optimized structure was fabricated using microwave integrated circuit (MIC) techniques on same substrate. The return loss was measured using the Vector Network Analyzer. The simulated and measured return loss shows the close agreement. © 2012 IEEE.

Sharma R.,Rajasthan Technical University Kota | Kumar M.,Rajasthan Technical University Kota
Proceedings - 4th International Conference on Computational Intelligence and Communication Networks, CICN 2012 | Year: 2012

In this paper, the performance of two dual-band printed fed-fed antennas is investigated, which have circular and hexagonal geometrical shapes. The hexagonal antenna shows the centre frequencies 1.6GHz and 3.8GHz and the circular antenna operates on 1.6GHz and 4GHz. These dual band antennas show the good simulated return loss and radiation characteristics. The proposed antenna designs are simulated on electromagnetic (EM) simulation software using FR-4 substrate with dielectric constant of 4.4 and thickness of 1.6 millimeter(mm). The proposed antennas have compact structures, the total size is 60x64 mm 2 and fed with 50Ω microstrip line by optimizing the width of partial ground. With the design, the return loss is lower than-10dB. A single rectangular slot is cut to obtain dual band operation. The proposed antenna is easy to integrate with microwave circuitry for low manufacturing cost. The antenna structure is flat, and its design is simple and straightforward. These antennas can be used in wireless communication. © 2012 IEEE.

Saraswat R.K.,Government of Rajasthan | Kumar M.,Rajasthan Technical University Kota
Progress In Electromagnetics Research B | Year: 2015

An octagonal shape patch antenna with switchable inverted L-shaped slotted ground is designed for frequency band reconfigurable and experimentally validated. The antenna is capable of frequency band switching at five different states including an ultra wideband (UWB) state, two narrowband states and a dual-band state by using RF switching element p-i-n diodes. In the case of ultrawide band (UWB) state, the proposed antenna operates over impedance bandwidth of 141% (2.87- 16.56GHz) under simulation and 139% (2.85-15.85 GHz) in measurement with return loss S11 < -10 dB. For two narrowband states, 10 dB impedance bandwidth achieved is 16% (5.05-5.91 GHz) and 11% (8.76-9.80 GHz) under simulation and 14% (5.01-5.79 GHz) and 10% (8.68-9.69 GHz) in measurement, respectively. For the dual band state, 10 dB impedance bandwidth of 2.21-2.52 GHz (13%) & 5.07- 5.89 GHz (15%) and 2.18-2.52 GHz (14%) & 8.78-9.71 GHz (10%) under simulation and 2.20-2.50 GHz (12%) & 5.05-5.90 GHz (15%) and 2.19-2.50 GHz (13%) & 8.70-9.60 GHz (9%) in measurement with return loss S11 < -10 dB. The proposed antenna is capable to serve in different wireless communication applications such as WLAN [802.11b/g/n (2.4-2.48 GHz), 802.11a/h/j/n (5.2 GHz), ISM band (2.4- 2.5GHz)], Bluetooth (2400-2484 MHz), WiMAX (2.3-2.4 & 5.15-5.85 GHz), WiFi (2.40-2.48, 5.15-5.85 GHz) and UWB (3.1-10.6GHz). It also works at 9.2 GHz where airborne radar applications are found. Next, the antenna gain is improved with the help of a circular loop frequency selective surface (FSS) and a PEC (perfect electric conductor) sheet. Measured peak gain represents average improvements about 4 dB-5 dB over the UWB band. Experimental results seem in good agreement with the simulated ones of the proposed antenna with and without the frequency selective surface.

Gupta R.,Rajasthan Technical University Kota
Journal of Electrical Engineering and Technology | Year: 2010

This paper proposes the use of fuzzy applications to a 4-machine and 10-bus system tocheck stability in open conditions. Fuzzy controllers and the excitation of a synchronousgenerator are added. Power system stabilizers (PSSs) are added to the excitation system to enhance damping during low frequency oscillations. A fuzzy logic power system stabilizer (PSS) for stability enhancement of a multi-machine power system is also presented. To attain stability enhancement, speed deviation (Δω) and acceleration (Δω̄) of the Kota Thermal synchronous generator rotor are taken as inputs to the fuzzy logic controller. Thesevariables have significant effects on the damping of generator shaft mechanical oscillations. The stabilizing signals are computed using fuzzy membership functions that are dependent on these variables. The performance of the fuzzy logic PSS is compared with the openpower system, after which the simulations are tested under different operating conditionsand changes in reference voltage. The simulation results are quite encouraging and satisfactory. Similarly, the system is tested for the different defuzzification methods, and based on the results, the centroid method elicits the best possible system response.

Bhati P.S.,Rajasthan Technical University Kota | Gupta R.,University of Kota
International Journal of Electrical Power and Energy Systems | Year: 2013

A robust fuzzy logic power system stabilizer (FLPSS) based on evolution and learning is proposed in this paper. A hybrid algorithm that combines learning and evolution is developed whereby each one complements other's strength. Parameters of FLPSS are encoded in chromosome (individual) of genetic algorithm (GA) population. Population of FLPSS in GA learns to stabilize electromechanical oscillations in power system at an operating point, as the best fitness becomes large steady value during successive generations. Operating region of FLPSS is enlarged by learning more operating points over the operating domain. Best FLPSS drawn from last generation is saved as designed FLPSS. Effectiveness of the proposed method is validated on a single machine infinite bus (SMIB) power system. Promising optimal stabilizing performance with designed FLPSS for considered power system is obtained at wide range of operating points. © 2013 Elsevier Ltd. All rights reserved.

Jamwal P.K.,Rajasthan Technical University Kota | Xie S.Q.,University of Auckland | Hussain S.,University of Auckland | Parsons J.G.,University of Auckland
IEEE/ASME Transactions on Mechatronics | Year: 2014

This paper presents the development of a novel adaptive wearable ankle robot for the treatments of ankle sprain through physical rehabilitation. The ankle robot has a bioinspired design, devised after a careful study of the improvement opportunities in the existing ankle robots. Robot design is adaptable to subjects of varying physiological abilities and age groups. Ankle robot employs lightweight but powerful pneumatic muscle actuators (PMA) which mimics skeletal muscles in actuation. To address nonlinear characteristics of PMA, a fuzzy-based disturbance observer (FBDO) has been developed. Another instance of an adaptive fuzzy logic controller based on Mamdani inference has been developed and appended with the FBDO to compensate for the transient nature of the PMA. With the proposed control scheme, it is possible to simultaneously control four parallel actuators of the ankle robot and achieve three rotational degrees of freedom. To evaluate the robot design, the disturbance observer, and the adaptive fuzzy logic controller, experiments were performed. The ankle robot was used by a neurologically intact subject. The robot-human interaction was kept as active-passive while the robot was operated on predefined trajectories commonly adopted by the therapists. Trajectory tracking results are reported in the presence of an unpredicted human user intervention, use of compliant and nonlinear actuators, and parallel kinematic structure of the ankle robot. © 1996-2012 IEEE.

Nigam H.,Rajasthan Technical University Kota | Kumar M.,Rajasthan Technical University Kota
International Conference on Advanced Communication Technology, ICACT | Year: 2014

OFDM based Ultra Wideband (UWB) system combines OFDM modulation technique with a multi banding approach, which divides the spectrum into several sub-bands, whose bandwidth is approximately 528MHz. It is a popular method for high data rate wireless communications. MIMO techniques promise a significant boost in the performance of OFDM systems. In this paper, a novel design UWB MIMO OFDM system using a compact double-sided printed antenna having ultra-wideband and band-notched characteristic is proposed. The UWB antennas are designed on CST Microwave studio simulation software with return loss less than -10dB, and further using the results from CST, OFDM transmission and reception on a MIMO system is done on MATLAB software. The MIMO UWB antennas are designed using polarization diversity of the individual antennas. The performance of this system is studied using BPSK modulation and finally bit error rate and operating range is obtained. The transmitting bandwidth is UWB (i.e. 3.1-10.6GHz) and the receiving bandwidth is notch UWB (notch bandwidth 5-5.9GHz) are chosen to reduce the interference at the receiver side. Furthermore, a MIMO UWB system is designed at a frequency of 9.4GHz that is used for micro power radar application in the ultra wideband removing the interference from WLAN band. © 2014 Global IT Research Institute (GIRI).

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