Faculty Publications
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Item Modeling and design of field programmable gate array based real time robust controller for active control of vibrating smart system(Academic Press, 2015) Parameswaran, A.P.; Ananthakrishnan, B.; Gangadharan, K.V.The current paper focuses on accurate mathematical modeling of a vibrating piezoelectric laminate cantilever beam theoretically as well as experimentally so as to obtain the best replication of the system dynamics on the software platform for simulation studies. The developed models were tested for accuracy in time as well as frequency domain by employing the sweep sine test. The focus of the study is on the flexural modes of vibrations of the cantilever beam. Here, modeling is focused on the first vibratory mode as it has been observed that the effects of felt vibrations would be maximum in terms of system stability and its operational efficiency when the excitation frequency matches with the first natural frequency of the system (fn1). This was validated by appropriate non-parametric modeling of the smart system by subjecting it to the Impact Hammer test. Development of accurate system models play an important role in designing and testing various control algorithms for reliable active vibration control (AVC). In the final stage, a real time active vibration robust controller was designed using a proportional derivative sliding mode control (PDSMC) technique and deployed on a Field Programmable Gate Array (FPGA) platform. The efficiency of the developed real time controller was proved in time as well as frequency domains by subjecting the closed loop system to harmonic excitations at first natural frequency as well as sweep sine test focussing on the first vibratory mode with the conclusion that the developed controller will function satisfactorily at higher modes of vibrations. © 2015 Elsevier Ltd.Item Design and development of a model free robust controller for active control of dominant flexural modes of vibrations in a smart system(Academic Press, 2015) Parameswaran, A.P.; Ananthakrishnan, B.; Gangadharan, K.V.Real physical vibrating smart systems exhibit a lot of nonlinearities in their dynamics. Undesirable vibrations, particularly in the regions of first as well as second resonance, play a very important role in deteriorating the stability of the system as well as its operational efficiency. The work presented in the paper focuses on an analytical technique of mathematical modeling of a vibrating piezoelectric laminate cantilever beam which is considered to be the smart system. The natural frequencies of the vibrating smart system are determined from the ANSYS simulation studies and experimentally, it is found that the vibrations induced voltage is maximum at the first followed by the second natural frequencies. Hence, the smart system is modeled analytically through finite element technique using the Euler-Bernoulli beam theory for the first two flexural modes of vibrations. To account for the possible nonlinearities, a suitable robust controller is designed based on sliding mode technique. Simulation studies on the developed analytical model indicated a high performance of the designed controller in controlling the vibrations at first and second resonance regions. Also, the designed controller was found to be effective in its operations when the excitation varied over a large range covering the first two natural frequencies. In the final stage, the designed robust controller was successfully prototyped on a Field Programmable Gate Array (FPGA) platform using LabVIEW coupled with Compact Reconfigurable Input Output (cRIO-9022) controller configured in its FPGA interface mode and the resulting robust FPGA controller successfully controlled the occurring system vibrations. © 2015 Elsevier Ltd.Item Developing the viscoelastic model and model-based fuzzy controller for the MRE isolator for the wide frequency range vibration isolation(Springer Science and Business Media Deutschland GmbH, 2022) Kiran, K.; Poojary, U.R.; Gangadharan, K.V.The ability to mitigate the vibrations by a magnetorheological elastomer (MRE) isolator varies with the amplitude of the excitation and the magnetic field. To implement semi-active vibration control, a mathematical model representing the dynamic response over a wide frequency range is crucial. In the present study, an attempt was made to develop a mathematical model for the designed MRE isolator over a wide frequency range under different operating conditions. A model-based fuzzy controller was developed to implement semi-active control attributes over a broadband frequency. The methodology entails that the MRE isolator operating in shear mode was designed. The performance of the isolator was evaluated over a frequency range of 15–80 Hz with varying input currents and excitation amplitudes. The transmissibility response of MRE isolator was mathematically represented using viscoelastic constitutive relations. The isolator system was represented in state-space form, and its parameters were determined by minimizing the mean square error between experimental and model responses. A polynomial function was used to generalize variations in viscoelastic model parameters with respect to the input current. Based on the controller stopping frequency, a relationship was established between the current input to the MRE isolator and the excitation amplitude. Using the mathematical equations, a model-based fuzzy controller was developed and tested in simulation and real-time conditions. The results show that the controller effectively isolates the vibration amplitude at various excitation amplitudes and frequencies. © 2022, The Author(s).Item Numerical and Experimental Investigations on Robust Output Feedback Control for Active Vibration Attenuation of Flexible Smart System(Institute of Electrical and Electronics Engineers Inc., 2023) Parameswaran, A.P.; Padmasali, A.N.; Gangadharan, K.V.This paper investigates the prototyping and implementation of an output feedback-based robust controller on a Field Programmable Gate Array (FPGA) platform. The Smart System under Test (SSuT) in this submission is a flexible cantilever beam bonded with Piezoelectric (PZT 5H) patches that act as a sensor as well as an actuator (perturbance creation as well as control actuation). For ease of modeling and subsequent controller design in the laboratory studies, the low-frequency dynamics of the smart system are approximated to only a Single Degree of Freedom (SDOF) in terms of flexural vibrations. The SSuT is modeled analytically through finite element modeling and experimentally through sub-space system identification process. The developed models' accuracy is compared with the experimental results of non - parametric modeling. The developed models are then used to conduct the simulation studies with the designed robust output feedback controller in the closed loop. Apart from the simulation studies, the designed controller was also prototyped on an FPGA platform using LabVIEW FPGA with the associated hardware in loop to carry out the experimental validation of its performance. The robustness and efficiency of the prototype controller to control the system vibrations in real-time were proved through extensive tests at single resonant frequencies and a range of frequencies encompassing the dominant resonant regions in the flexural mode. Findings from this study are further used to ensure satisfactory active vibration control of smart cantilever systems in various heavy/aerospace industries by approximating them to suitable benchmark systems in the laboratory. © 2013 IEEE.