V.I.George
@htttps:
Professor and Head EEE Dept
Mar Baselios Christian College of Engg and Technology
Dr. V. I. George
(M) 9448548101, E mail- vig_rect@, drvigeorge@
A Brief Biodata
• V. I. George was born in 1961 and completed BE in Electrical Power Engg. (1983) Mysore University, M.Tech (1987) in Instrumentation and Control Engg from NIT, Calicut, and Ph. D (2004) in ‘Robust Control of Dynamic Systems’ from NIT, Tiruchirappalli.
• He joined MIT, Manipal as a faculty in the department of Electrical and Electronics Engineering in 1985, 1992 promoted as a Reader, 2004 as a Professor and Head in the Dept. of Instrumentation and Control Engineering (ICE). During his tenure as HOD of Dept of ICE started two postgraduate programs, one, in ‘Control systems’, and the other in ‘Astronomy and Space Engg’, which was later renamed as Aerospace Engg, and started the Control Instrumentation System Conference (CISCON) in 2004 at MIT, Manipal.
• Responsibilities at Jaipur: During the period 2012 -13 deputed to Manipal University Jaipur (MUJ) with the duties of Registrar,
EDUCATION
BE in Electrical Power Engg. (1983) Mysore University,
M.Tech (1987) in Instrumentation and Control Engg from NIT, Calicut,
Ph. D (2004) in ‘Robust Control of Dynamic Systems’ from NIT, Tiruchirappalli.
RESEARCH INTERESTS
Control Systems, Instrumentation , Aerospace control
Scopus Publications
Scopus Publications
Anna Merine George, Ciji Pearl Kurian, S. Y. Kulkarni, Veena K N, and V. I. George
IEEE
With the increasing popularity of Internet-of-Things (IoT) based building automation and lighting controls in the interior, the power management of IoT devices is a concern. Researchers globally are working on Indoor high-performance photovoltaics, which can power IoT devices. Here arises the need for experimentation with Indoor Photovoltaics (IPV) under varying interior lighting conditions that includes both artificial light and daylight. This paper focuses on experimental verification of the IPV characterization under indoor lighting conditions, adopting the recent human-centric lighting challenges. The paper presents empirical modeling of indoor irradiance and Photovoltaic cells to estimate its I-V characteristics and focuses on their operation at indoor illumination levels. A crucial requirement for accomplishing self-sustainability is the ability of IoT devices to be self-powered.
Navya Thirumaleshwar Hegde, V. I. George, and C Gurudas Nayak
ACM
This paper gives the dynamic modeling and design of a controller for autonomous Vertical take-off and landing (VTOL) Tri-Tilt rotor hybrid Unmanned Aerial Vehicle (UAV). Nowadays, UAVs have experienced remarkable progress and mainly categorized into fixed-wing UAVs and rotary-wing UAVs. The Tri Tiltrotor UAV models are derived mathematically using Euler's force and moment equations for VTOL to horizontal flight and vice-versa using MATLAB. The development of fully autonomous and self-guided UAVs would reduce the risk to human life. The applications consist of inspection of coasts, terrain, border, patrol buildings, rescue teams, police, and pipelines. A Proportional-Integral-Derivative control method is proposed for UAVs attitude and altitude stabilization. The results reveal that the controller accomplishes adaptability, robust performance and stability in the transition mode.
Suresh Kumar Suraj, Vadakkekkara Itty George, I. Thirunavukkarasu, and Tinu Valsa Paul
Springer Singapore
Navya Thirumaleshwar Hegde, V. I. George, C. Gurudas Nayak, and Aldrin Claytus Vaz
Emerald
PurposeThis paper aims to provide a mathematical modeling and design of H-infinity controller for an autonomous vertical take-off and landing (VTOL) Quad Tiltrotor hybrid unmanned aerial vehicles (UAVs). The variation in the aerodynamics and model dynamics of these aerial vehicles due to its tilting rotors are the key issues and challenges, which attracts the attention of many researchers. They carry parametric uncertainties (such as non-linear friction force, backlash, etc.), which drives the designed controller based on the nominal model to instability or performance degradation. The controller needs to take these factors into consideration and still give good stability and performance. Hence, a robust H-infinity controller is proposed that can handle these uncertainties.Design/methodology/approachA unique VTOL Quad Tiltrotor hybrid UAV, which operates in three flight modes, is mathematically modeled using Newton–Euler equations of motion. The contribution of the model is its ability to combine high-speed level flight, VTOL and transition between these two phases. The transition involves the tilting of the proprotors from 90° to 0° and vice-versa in 15° intervals. A robust H-infinity control strategy is proposed, evaluated and analyzed through simulation to control the flight dynamics for different modes of operation.FindingsThe main contribution of this research is the mathematical modeling of three flight modes (vertical takeoff–forward, transition–cruise-back, transition-vertical landing) of operation by controlling the revolutions per minute and tilt angles, which are independent of each other. An autonomous flight control system using a robust H-infinity controller to stabilize the mode of transition is designed for the Quad Tiltrotor UAV in the presence of uncertainties, noise and disturbances using MATLAB/SIMULINK. This paper focused on improving the disturbance rejection properties of the proposed UAV by designing a robust H-infinity controller for position and orientation trajectory regulation in the presence of uncertainty. The simulation results show that the Tiltrotor achieves transition successfully with disturbances, noise and uncertainties being present.Originality/valueA novel VTOL Quad Tiltrotor UAV mathematical model is developed with a special tilting rotor mechanism, which combines both aircraft and helicopter flight modes with the transition taking place in between phases using robust H-infinity controller for attitude, altitude and trajectory regulation in the presence of uncertainty.
Akhil Appu SHETTY, Vadakekara Itty GEORGE, Chempi Gurudas NAYAK, and Raviraj SHETTY
The Scientific and Technological Research Council of Turkey (TUBITAK-ULAKBIM) - DIGITAL COMMONS JOURNALS
Stereo matching algorithms generate disparity maps, which contain the depth information of the environment, from two or more images of a scene taken from different viewpoints. The process of obtaining dense disparity maps is a problem which is still being actively researched. The presence of radiometric differences in the images only further complicates the stereo matching problem. In the present research work, the images are initially split into small patches of pixels, such that pixels in each patch have similar intensities. The authors attempt to study the effect of the parameters, namely, tuning parameter ‘α ’ and the number of segments, while the images are subjected to variations in exposure and illumination. The value ‘α ’ performs the function of a weight signifying the contribution of each data cost, when the two data costs are combined in a linear fashion. Lastly, the results of this methodology are compared with other methods that try to tackle the problem of stereo matching under radiometric variations.
Navya Thirumaleshwar Hegde, V.I. George, C. Gurudas Nayak, and Kamlesh Kumar
Emerald
Purpose The purpose of this paper is to give reviews on the platform modeling and design of a controller for autonomous vertical take-off and landing (VTOL) tilt rotor hybrid unmanned aerial vehicles (UAVs). Nowadays, UAVs have experienced remarkable progress and can be classified into two main types, i.e. fixed-wing UAVs and VTOL UAVs. The mathematical model of tilt rotor UAV is time variant, multivariable and non-linear in nature. Solving and understanding these plant models is very complex. Developing a control algorithm to improve the performance and stability of a UAV is a challenging task. Design/methodology/approach This paper gives a thorough description on modeling of VTOL tilt rotor UAV from first principle theory. The review of the design of both linear and non-linear control algorithms are explained in detail. The robust flight controller for the six degrees of freedom UAV has been designed using H-infinity optimization with loop shaping under external wind and aerodynamic disturbances. Findings This review will act as a basis for the future work on modeling and control of VTOL tilt rotor UAV by the researchers. The development of self-guided and fully autonomous UAVs would result in reducing the risk to human life. Civil applications include inspection of rescue teams, terrain, coasts, border patrol buildings, police and pipelines. The simulation results show that the controller achieves robust stability, good adaptability and robust performance. Originality/value The review articles on quadrotors/quadcopters, hybrid UAVs can be found in many literature, but there are comparatively a lesser amount of review articles on the detailed description of VTOL Tilt rotor UAV. In this paper modeling, platform design and control algorithms for the tilt rotor are presented. A robust H-infinity loop shaping controller in the presence of disturbances is designed for VTOL UAV.
Akhil Appu Shetty, V.I. George, C. Gurudas Nayak, and Raviraj Shetty
Inderscience Publishers
Navya Thirumaleshwar Hegde, V. I. George, and C. Gurudas Nayak
Springer Singapore
Navya Thirumaleshwar Hegde
Institute of Advanced Scientific Research
Akhil Appu Shetty
Institute of Advanced Scientific Research
Susan G. Varghese, Ciji Pearl Kurian, V.I. George, Anupriya John, Varsha Nayak, and Anil Upadhyay
Institution of Engineering and Technology (IET)
ZigBee standard is the popular communication protocol for wireless sensor networks (WSN) and Internet of Things (IoT) networks. An energy efficient WSN technology is a good choice for an IoT based lighting control technology. This article is a comparative analysis for finding the quality of service parameters provided by the different topologies of ZigBee for a wireless networked lighting control system. In order to estimate the energy consumption in ZigBee topologies for lighting automation, this work analyses the star, mesh, and tree topology-based WSN with two routing protocols Adhoc on-demand distance vector (AODV) and dynamic source routing (DSR). Lighting automation using wireless control networks with sensor-actuator nodes in a laboratory is considered as the test scenario. The applicability of ZigBee topologies for IoT-based lighting automation is discussed by the evaluation of performance parameters like average jitter, throughput, end-to-end delay, and energy model.
Susan G. Varghese, Ciji Pearl Kurian, Vadakekkara Itty George, and T. S. Sudheer Kumar
Institute of Electrical and Electronics Engineers (IEEE)
Automated lighting can achieve significant energy savings. A daylight-artificial light integrated system with the camera as the sensor and wireless sensor actuator networked (WSAN) system is presented here. The workplane luminance, the window luminance, and the discomfort glare position of the user are extracted from the image of the workspace captured by the camera. The findings of this paper are the usage of the camera as luminance meter and how this information is used in the control of LED dimming based on consumer comfort. A novel camera-based fuzzy controller for window blind, considering visual, and thermal comfort, is designed, based on the parameters extracted from the image, to optimize the illuminance and uniformity for a test space. The control system integrates luminaire and window blind control. The model-based design approach provides visual and thermal comfort for the consumer without compromising on energy consumption. The real time implementation of the shading and lighting integrated model, with daylight adaptation and the wireless networked sensor-actuation system is shown in this paper. The performance of the wireless networked lighting scheme is analyzed, by evaluating the energy consumption of the nodes in idle, transmit, and receive mode.
SG Varghese, CP Kurian, VI George, M Varghese, and TM Sanjeev Kumar
SAGE Publications
Energy efficiency strategies based on daylight-artificial light integration have grown exponentially in recent years. Taking into account the dynamics to be considered for control and the dependence on natural and occupancy factors, it is better to use a test workbench prior to setting up the final control scheme. This work describes a climate model based test workbench for the real time testing of the control of luminaires and window blinds in a daylight-artificial light integrated scheme. The established climate model based control scheme suitable for the optimum integration of visual comfort, thermal comfort, and energy consumption can be tested for any ecological conditions. The input irradiance from a BF5 sensor, the internal temperature from a Micro DAQ logger, the occupancy and photo sensors associated with the luminaire all provide input data for the test workbench. A fuzzy logic based motorized window blind controller and look-up table based dimming of LED luminaires are used to set the required illuminance with reduced load on the heating, ventilation, and air conditioning system. The anticipated synergetic effects of the test workbench have been validated using real time climate data. The test work bench is established on a Labview platform and developed as a standalone system using myRIO.
Akhil Appu Shetty, V. I. George, C Gurudas Nayak, and Raviraj Shetty
IEEE
This paper discusses a method of using disparity maps, generated from a stereo matching process, to be used for obstacle detection. The disparity map is a direct indicator of the distances the various objects have with respect to the cameras. This information can be further segmented to highlight the obstacle regions. Once the obstacle regions are highlighted, this information can be used for a path planning algorithm to generate the required control signals to direct the robot from a source position to destination position while avoiding the detected obstacles.
Navya Thirumaleshwar Hegde, V. I. George, and C Gurudas Nayak
IEEE
This paper explains the mathematical modelling and flight controller design for autonomous Vertical take-off and landing (VTOL) Tri-Tilt rotor hybrid Unmanned Aerial Vehicle (UAV). A tri Tilt rotor UAV is a combination of vertical flight performance of a helicopter and forward flight capability of an aircraft. The front two rotors are used to tilt from the horizontal position to the vertical and vice versa, and the third middle rotor is placed in the aft of centerline of fuselage with a lesser angle. UAVs can be classified into two main types, i.e., fixed-wing UAVs and VTOL UAVs. The mathematical model of the Tri Tilt rotor UAV using force and moment equations are derived for vertical take-off to horizontal flight and vice-versa using MATLAB/SIMULINK. The development of self-guided and fully autonomous UAVs would result in reducing the risk to human life. Civil applications include inspection of rescue teams, terrain, coasts, border patrol buildings, police, and pipelines. A Proportional-Derivative control approach is used to stabilize the altitude and attitude of the UAV. The results obtained from the simulation reveals that the proposed controller achieves robust stability, good adaptability and robust performance in the transition corridor.
Navya Thirumaleshwar Hegde, V. I. George, and C Gurudas Nayak
IEEE
The comparative study and analysis of five different aircrafts namely, Cessna 182 (Class I), Beech 99 (Class II), Cessna T37A (Class II), Boeing 747 200 (Class III), McDonnell Douglas F4 (Class IV) at different flight conditions is presented in this paper. The mathematical model and dynamic characteristics of a generic aircraft is simulated, where some assumptions are made while deriving the models. The aircraft dynamic characteristics are derived as MATLAB functions and simulated. It gives full 6DoF aircraft mathematical modelling using Euler angles, trimming at desired flight conditions and generation of linearized model. Simulation results shows that the stability of longitudinal/lateral directional dynamics depends on the aircraft geometric parameters, inertial characteristics and flight conditions. Greater the value of ωNSP, higher the airspeed, resulting in faster dynamics of short period mode. As the altitude decreases, magnitude of ωNSP also decreases with increase in air density. The aircraft of lower size and weight associated with smaller value of Iyy leads to greater value of ωNSP. At low subsonic flight conditions (high values of CL1, low values for CDu) the value of ζPH is less as compared to the aircraft at higher subsonic conditions (lower values of CL1, higher values for CDu).
R Janani, Vinayambika S. Bhat, I. Thirunavukkarasu, and V. I. George
IEEE
In this article the authors have made an attempt to design and validate the PI controller based on the frequency based specifications on a lab scale distillation column. In general, the literature reveals the controller design based a specific formula, which leads to a static controller. In lab/Industrial scale most of the processes are dynamic in nature, hence the static controller concepts fail to prove its effectiveness in the presence of dynamic behaviors of the plant. In this article, wide range of stable $\\mathrm {K}_{\\mathrm {p}}$ and Ki values are plotted with fixed Kd for specific gain and phase margin. The design engineers are permitted to select any $\\mathrm {K}_{\\mathrm {p}}$ and Ki values based on the closed loop specifications required. The presented algorithm is simulated for the closed loop response of the lab scale binary distillation column model identified by Vinaya and Arasu [6], [7], [8]. The closed loop simulation with 30% uncertainty in all process parameters are also analyzed presented in this article. The Performance measure calculations for servo and regulatory responses are also reported. The experimental validation of the given control algorithm on a lab scale pilot plant distillation column is also found satisfactory to prove the control algorithm effectiveness.
Akhil Appu SHETTY, V. I. GEORGE, C Gurudas NAYAK, and Raviraj SHETTY
The Scientific and Technological Research Council of Turkey (TUBITAK-ULAKBIM) - DIGITAL COMMONS JOURNALS
Stereo matching algorithms are capable of generating depth maps from two images of the same scene taken simultaneously from two different viewpoints. Traditionally, a single cost function is used to calculate the disparity between corresponding pixels in the left and right images. In the present research, we have considered a combination of simple data costs. A new method to combine multiple data costs is presented and a fuzzy-based disparity selection method is proposed. Experiments with different combinations of parameters are conducted and compared through the Middlebury and Kitti Stereo Vision Benchmark.
Ciji Pearl Kurian, V.I. George, K. Pallavi, and Manu Varghese
IEEE
LED Luminaire integrating lighting control strategies has a significant role to pay in transforming the way energy used in commercial spaces. Though lighting control is a proven concept, the complexity and high capital investment prevent the deployment of such schemes. This simulation assisted study investigates the energy and cost implications of a large office located in India specifically at 9.9252°N, 78.1198°E. The energy savings and payback time of T5&CFL and LED luminaire with control schemes is presented, study shows the best results with scheduled occupancy with a photo sensor for window zones. For this to launch, a grouping of luminaires is carried out after accurate simulation of the building. The 3D plan prepared in AutoCAD is simulated using DIALux Evo 7, which gives the design, analysis and visualization of interior lighting. A MATLAB interface module helps to analyze the daylight dependency, perceived adequacy of illumination, energy comparison and payback period.
Anna Merine George, V.I. George, and Mary Ann George
IEEE
Traffic Congestion and traffic monitoring is one of the important problems all over the world. This work uses IOT and Adaptive Neuro Fuzzy Inference System (ANFIS) to improve traffic conditions. An ANFIS traffic light controller with inputs as waiting time and vehicle density is developed using MATLAB SIMULINK environment. A camera is used to capture the traffic scenes and this image is transferred to the cloud using Arduino UNO and ThingSpeak Platform. The image is then analyzed in the server using ANFIS controller and appropriate control signals are sent to the traffic signals.
Vinayambika S. Bhat, I. Thirunavukkarasu, V. I. George, and C Sreelatha
IEEE
The binary distillation column is a highly nonlinear and higher order system, where the control of temperatures plays a very vital role in maintaining the purity of the end products. The article deals with the Proportional Integral Derivative (PID) controller design in both centralized and decentralized control strategy. The decentralized controller is designed with an additional controller called as the decoupler. The centralized controller that is designed is with decoupling process with an additional integral for better control with limited control interactions. The closed loop servo response is recorded. Also, both the control algorithm are validated by implementing it on a pilot plant binary distillation column.
Vidya S. Rao, V. I. George, Surekha Kamath, and C. Shreesha
IEEE
Station keeping, or hovering in spite of uncertainties like sensor or actuator failures, is important for a variety of applications like load delivery and air-sea rescue. During rescue operations helicopter will be in hazardous surroundings often which may lead to sensor or actuator failure. These failures may take helicopter to instability. Rescue operation should not be affected along with the assurance of stability of helicopter even under sensor or actuator failure. Since it is a manned air vehicle due to sensor, actuator failures during its operation, human life should not be at risk. Hence control algorithm should be reliable. This has motivated the present work to build a reliable robust PID controller to tolerate the system sensor, actuator failures. The experimentation is carried on TRMS because it has similar dynamic characteristics as that of helicopter system though some simplifications are made and TRMS has been proven to be a good benchmark problem to test and explore flight control methodologies. Design of reliable robust PID controller is done using MATLAB which is interfaced with TRMS setup. The simulation and real time implementation results are presented.