V.I.George

Scopus Publications

Preface

Non-prehensile Modes of Object Manipulation: A Comprehensive Review
Mukund Kumar Menon, V. I. George, and Shashank Goyal
Springer Nature Singapore

Nonlinear Dynamic Modeling of a Quadrotor and Its Control Using Sliding Mode Controller
Tinu Valsa Paul, George Vadakkekara Itty, and Thirunavukkarasu Indiran
American Society of Civil Engineers (ASCE)

Experimental Investigations towards the Design of Power Management System Using Indoor Photovoltaic
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.

State of the Art Sliding Mode Controller for Quadrotor Trajectory Tracking
Tinu Valsa Paul, Thirunavukkarasu Indiran, George Vadakkekara Itty, Suraj Suresh Kumar, and Chirag Gupta
Springer Nature Singapore

Development of a Nonlinear Model Predictive Control-Based Nonlinear Three-Mode Controller for a Nonlinear System
Suraj Suresh Kumar, Thirunavukkarasu Indiran, George Vadakkekkara Itty, Prajwal Shettigar J, and Tinu Valsa Paul
American Chemical Society (ACS)
This paper presents the novelty on a nonlinear proportional integral derivative (NPID) controller developed from the gain values obtained using the Lyapunov-based nonlinear model predictive controller (LyNMPC). The tuning parameters of the proposed controller are taken from the dynamics of the nonlinear system, and these parmeters are dynamic with their value varying according to the error in the system. In this article, the authors have considered two highly nonlinear systems, namely, batch polymerization reactor and quadrotor unmanned aerial vehicle systems. The nonlinear mathematical modeling of the batch reactor as well as the quadrotor system considered from the past literature of authors. The acrylamide polymerization reaction under consideration is an exothermic reaction, thereby making the temperature profile tracking and control a challenging task. The primary aim of this article is to develop the NPID controller based on the LyNMPC algorithm and to validate the NPID on a batch reactor bench-scale plant and on an hardware-in-the-loop platform for the quadrotor hardware. A comparative study of trajectory tracking and control capabilities of LyNMPC on derived non-linear models of the batch reactor and quadrotor system is presented. The system mathematical models are obtained with the help of the first-principle energy balance equation for the batch reactor and with the nonlinear dynamics of the quadrotor which is derived based on Newton–Euler formulations. With LyNMPC, the stability of the nonlinear systems can be improved because the error sensitivity is considered in the cost function.

Simulation of Nonlinear Proportional Integral Derivative Controller for a Nonlinear Model of a HexSoon EDU 450 Quadrotor Aerial Robot
Suraj Suresh Kumar, Thirunavukkarasu Indiran, George Vadakkekara Itty, and Chirag Gupta
IEEE
This paper is written in conjunction with the research for developing the control schemes for a model of quadrotor unmanned aerial vehicle based on actual hardware. The primary aim is to reflect the outcomes of designing nonlinear control algorithms for in-situ hardware equipment where the physical parameters have been determined through direct measurement and estimation. A comprehensive study of the trajectory tracking and control capabilities of Non-linear Proportional Integral Derivative control on a derived non-linear model of the quadrotor system is presented. The system mathematical model is obtained with the help of the nonlinear dynamics of the quadcopter which is derived with the help of Newton-Euler formulations. Thus, the model obtained includes the aerodynamic effects and the rotor dynamics of the quadrotor. Simulations were used for evaluating and comparing the performances of the two control techniques developed between their dynamic performances and stability.

Tri-Tilting Rotor Fixed-Wing VTOL UAV: Dynamic Modelling and Transition Flight Control
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.

Design and Simulation of a Sliding Mode-Based Control Design for a Quadrotor UAV
Suresh Kumar Suraj, Vadakkekkara Itty George, I. Thirunavukkarasu, and Tinu Valsa Paul
Springer Singapore

Application of robust H-infinity controller in transition flight modeling of autonomous VTOL convertible Quad Tiltrotor UAV
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.

Performance analysis of a fuzzy disparity selector for stereo matching of image segments under radiometric variations
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.

Design, dynamic modelling and control of tilt-rotor UAVs: a review
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.

Multiple data cost-based stereo matching method to generate dense disparity maps from images under radiometric variations
Akhil Appu Shetty, V.I. George, C. Gurudas Nayak, and Raviraj Shetty
Inderscience Publishers

Preface

Performance analysis of a tiltrotor UAV flight stability using PID controller
Navya Thirumaleshwar Hegde, V. I. George, and C. Gurudas Nayak
Springer Singapore

Design of H-infinity controller for VTOL tiltrotor unmanned aerial vehicle
Navya Thirumaleshwar Hegde
Institute of Advanced Scientific Research

A method for navigation of autonomous vehicles in outdoor environment through stereo correspondence
Akhil Appu Shetty
Institute of Advanced Scientific Research

Transition flight modeling and robust control of a VTOL unmanned quad tilt-rotor aerial vehicle

Comparative study of zigBee topologies for IoT-based lighting automation
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.

Daylight-Artificial Light Integrated Scheme Based on Digital Camera and Wireless Networked Sensing-Actuation System
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.

Climate model based test workbench for daylight-artificial light integration
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.

Disparity Maps Based Path Planning Algorithm for Autonomous Robot Navigation
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.

Modelling and Transition flight control of Vertical Take-Off and Landing unmanned Tri-Tilting Rotor Aerial Vehicle
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.

A Comparative Analysis of Longitudinal and Lateral Directional Dynamics of Aircraft from Different Classes
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).

Identifying the Stabilizing Regions of PI Controller based on Frequency Specifications for a Lab Scale Distillation Column
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.

V.I.George

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