Research

@article {101002cae21907, issn = {1099-0542}, author = {Concha Antonio and Delgado Chavez Ana Cristina and Balagurusamy Nagamani and Narayanasamy Rajeswari and Gadi Suresh K.}, title = {A computer-based educational tool for simulating multifactorial experiments of physical processes}, journal = {Computer Applications in Engineering Education}, volume = {26}, number = {3}, pages = {559-565}, keywords = {educational tool, experimental design, generating examples, multifactorial model, problem-based learning}, year = {2018}, month = {feb}, doi = {10.1002/cae.21907}, url = {https://onlinelibrary.wiley.com/doi/abs/10.1002/cae.21907}, eprint = {https://onlinelibrary.wiley.com/doi/pdf/10.1002/cae.21907}, abstract = {In this article, challenges in designing example problems of multifactorial experiments for an academic purpose are identified, and an algorithm for simulating multifactorial experiments is presented. It is based on a proposed mathematical function, which mimics a physical system, can be employed for any number of finite factors, and contains a unique peak, with which a unique optimal solution for an experiment is guaranteed. The proposed algorithm is implemented on an application developed with JavaScript, HTML, and CSS, which has been tested in the classroom for highlighting all characteristics of experimental design.} gsktype = "artJCR", }

@Article{101007s1084601604206, author="S. K. Gadi and Osorio-Cordero, Antonio and Lozano-Leal, Rogelio and Garrido, Ruben A.", title="Stability Analysis of a Human Arm Interacting with a Force Augmenting Device", journal="Journal of Intelligent {\&} Robotic Systems", year="2016", pages="1--10", abstract="This paper presents a stability analysis of the interaction between a human and a linear moving Force Augmenting Device (FAD). The analysis employs a mathematical model of the human arm, the FAD and their interaction. As a depart from past works, this article presents a stability analysis considering time-delays in the human model. A key ingredient in the analysis is the use of the Rekasius substitution for replacing the time-delay terms. It is proved that the human machine interaction is stable when the human model has no delays. When delays are considered in the human model, the analysis provides an upper bound for the time-delays preserving a stable interaction. Numerical simulations allow to assess the human-FAD interaction. An experiment is performed with a laboratory prototype, where a human operator lifts a load. It is observed that the human machine interaction is stable and the human operator is able to move the load to a desired position by experiencing very little effort.", issn="1573-0409", doi="10.1007/s10846-016-0420-6", month=sep, }

@article{101016jifacol201612175, title = "A Novel Numerical Approach to the MCLP Based Resilent Supply Chain Optimization ", journal = "IFAC-PapersOnLine ", volume = "49", number = "31", pages = "137 - 142", year = "2016", note = "12th IFAC Workshop on Intelligent Manufacturing Systems IMS 2016Austin, Texas, USA, 5—7 December 2016 ", issn = "2405-8963", doi = "10.1016/j.ifacol.2016.12.175", url = "http://www.sciencedirect.com/science/article/pii/S2405896316328464", pdf = {https://www.sciencedirect.com/science/article/pii/S2405896316328464/pdf}, author = "V. Azhmyakov and J.P. Fernández-Gutiérrez and S.K. Gadi and St. Pickl", abstract = "This paper deals with the Maximal Covering Location Problem (MCLP) for Supply Chain optimization in the presence of incomplete information. A specific linear-integer structure of a generic mathematical model for Resilient Supply Chain Management System (RSCMS) makes it possible to reduce the originally given \{MCLP\} to two auxiliary optimization Knapsack-type problems. The equivalent transformation (separation) we propose provides a useful tool for an effective numerical treatment of the original \{MCLP\} and reduces the complexity of algorithms. The computational methodology we follow involves a specific Lagrange relaxation procedure. We give a rigorous formal analysis of the resulting algorithm and apply it to a practically oriented example of an optimal \{RSCMS\} design. " }

@InProceedings{101109iceee20126421189, author = {S. K. Gadi and R. Lozano and R. Garrido and A. Osorio}, title = {{Stability Analysis and Experiments for a Force Augmenting Device}}, booktitle = {2012 9{th} International Conference on Electrical Engineering, Computing Science and Automatic Control (CCE)}, year = {2012}, pages = {1--6}, month = sep, publisher = {Institute of Electrical {\&} Electronics Engineers ({IEEE})}, abstract = {We present preliminary results of a one degree of freedom (DOF) linear moving force augmenting device (FAD) with a force sensor for enhancing the lifting capabilities of a human user. We perform a stability test of the feedback loop formed by the device and a model of the human operator. It is shown that the operator lifts a small fraction of the total weight of the load. The proposed control scheme is illustrated using numerical simulations and an experiment.}, doi = {10.1109/iceee.2012.6421189}, keywords = {force feedback;force sensors;lifting equipment;stability;FAD;feedback loop;force sensor;lifting capability enhancement;load handling;numerical simulation;one-DOF linear moving force augmenting device;one-degree of freedom linear moving force augmenting device;stability analysis;Force;Force sensors;Humans;Mathematical model;Stability analysis;Torque;Trajectory;Exoskeleton;force augmenting device;load handling}, }

@INPROCEEDINGS{101109ICEEE20167751223, author={R. Juarez and V. Azhmyakov and S. K. Gadi and F. G. Salas}, booktitle={2016 13th International Conference on Electrical Engineering, Computing Science and Automatic Control (CCE)}, title={Robust control for a class of continuous dynamical system governed by semi-explicit DAE with data-sample outputs}, year={2016}, pages={1--7}, abstract={This paper addresses the problem of robust control for a class of nonlinear dynamical systems in the continuous time domain. We deal with nonlinear models described by differential algebraic equations (DAEs) in the presence of bounded uncertainties. The full model of the control system under consideration is completed by linear sampling-type outputs. Main contribution of present manuscript is the proposal of a linear state feedback control design for this type of uncertain nonlinear system obtaining the required stability and robustness. Due to the need to the state feedback there is a need of the implementation of a Luenberguer observer. Finally, the applicability of the proposed method is illustrated by a computational example. A brief discussion on the main implementation issue is also included.}, keywords={control system synthesis;differential algebraic equations;nonlinear control systems;observers;robust control;state feedback;Luenberguer observer;continuous dynamical system;continuous time domain;data-sample outputs;differential algebraic equations;linear sampling-type outputs;linear state feedback control design;nonlinear dynamical systems;nonlinear models;robust control problem;semi-explicit DAE;state feedback;uncertain nonlinear system;Electronic mail;Ellipsoids;Linear matrix inequalities;Mathematical model;Robustness;Stability analysis;Symmetric matrices}, doi={10.1109/ICEEE.2016.7751223}, month=sep, }

@INPROCEEDINGS{101109ICEEE20167751224, author={V. Azhmyakov and R. Juarez and S. K. Gadi and L. A. G. Trujillo}, booktitle={2016 13th International Conference on Electrical Engineering, Computing Science and Automatic Control (CCE)}, title={Attractive ellipsoids based robust control design of switched systems: A geometrical approach}, year={2016}, pages={1--7}, abstract={This contribution deals with a robust control design for general switched affine control systems. Dynamical models under consideration are described by ordinary differential equations involving a switching mechanism and in the presence of bounded uncertainties. The design procedure we analyse is based on the newly elaborated attractive ellipsoids method ([33]). The stability and robustness of the resulting closed-loop system involves an abstract Clarke stability theorem. A short discussion on the obtained analytic results and possible applications and extensions is also included.}, keywords={closed loop systems;control system synthesis;differential equations;robust control;switching systems (control);Clarke stability theorem;attractive ellipsoid method;bounded uncertainties;closed-loop system;design procedure;dynamical models;ordinary differential equations;robust control design;switched systems;switching mechanism;Ellipsoids;Estimation;Robust control;Stability analysis;Switched systems;Switches}, doi={10.1109/ICEEE.2016.7751224}, month=sep, }

@INPROCEEDINGS{101109ICPCSI20178391942, author={A. Concha and E. K. Varadharaj and N. M. Hernandez-Rivera and S. K. Gadi}, booktitle={2017 IEEE International Conference on Power, Control, Signals and Instrumentation Engineering (ICPCSI)}, title={A novel implementation technique for genetic algorithm based auto-tuning PID controller}, year={2017}, pages={1403-1408}, abstract={The auto-tuning proportional-integral-derivative (PID) controllers based on genetic algorithms have many limitations in their implementation. For example, some chromosomes of the tuned genetic algorithms may cause closed-loop system instability, and some chromosomes tuned for an operating condition may cause instability for other operating conditions. This article provides the possible solutions for these problems. An implementation technique of a genetic algorithm is proposed based on these solutions. Numerical simulations are given to evaluate the proposed method applied to a system with variable parameters. Moreover, this technique is also used for controlling a brushless servo motor.}, keywords={Biological cells;Closed loop systems;Genetic algorithms;Linear programming;Sociology;Statistics;Tuning;Genetic algorithm;PID tuning}, doi={10.1109/ICPCSI.2017.8391942}, month={Sept}, }

@InProceedings{101109icstcc20146982382, author = {S. K. Gadi and Antonio Osorio and Rogelio Lozano}, title = {{Study of the Interaction between a One Degree of Freedom Force Augmenting Device and a Human Operator}}, booktitle = {2014 18{th} International Conference on System Theory, Control and Computing ({ICSTCC})}, year = {2014}, pages = {7--12}, month = oct, publisher = {Institute of Electrical {\&} Electronics Engineers ({IEEE})}, abstract = {In this paper a one degree of freedom (DOF) force augmenting device (FAD) is presented. A laboratory set-up has been built and some tests of the interaction between the FAD and a user were performed. The stability of the closed loop system is essential for the performance of the FAD. The FAD by itself is a stable device, but what is important is to assure the stability of the interaction between the FAD and a human being. To deal with this matter, two situations were analyzed. The case of no delays in the model is first considered. This situation might appear unrealistic, for this reason, a second analysis is performed considering a human model with delays. In order to deal with delays a Rekasius substitution is used. To perform the stability analysis, it is sufficient to apply the Routh-Hurtwitz criteria. Attempts with other techniques have given more conservative stability results. The stability has been proven for delays smaller than upper-bounds which have been computed. None of these upper-bounds are reached by any healthy human being. Therefore, we can assure that the whole system is stable for most of the practical situations. This proves the robustness of the closed loop system with respect to delays. In real time experiments, measurement from the sensors are normally noisy. In order to reduce the effect of the noise, a low pass filter was included. The introduction of this filter alters the order of the system, changing the stability conditions of the whole set up. So the stability analysis is performed again with the inclusion of the filter.}, doi = {10.1109/icstcc.2014.6982382}, keywords = {closed loop systems;man-machine systems;stability;DOF;FAD;Rekasius substitution;Routh-Hurtwitz criteria;closed loop system;human operator;one degree of freedom force augmenting device;stability analysis;Delays;Force;Laboratories;Mathematical model;Spinal cord;Stability criteria}, }

@InProceedings{101115imece201363751, author = {S. K. Gadi and Ruben A. Garrido and Rogelio Lozano and Antonio Osorio}, title = {{Stability Analysis for a Force Augmenting Device Considering Delays in the Human Model}}, booktitle = {Volume 12: Systems and Design}, year = {2013}, pages = {1--9}, month = nov, organization = {American Society of Mechanical Engineers}, publisher = {{ASME} International}, abstract = {This paper presents a stability analysis of the interaction between a human and a linear moving Force Augmenting Device (FAD). The analysis employs the mathematical models of the human, the FAD and their interaction. As a depart from past works, this article presents a stability analysis considering time-delays in the human model. A key ingredient in the analysis is the use of the Rekasius substitution for replacing the time-delay terms. It is proved that the human machine interaction is stable when the human model has no delays. The analysis provides an upper bound for the time-delays preserving a stable interaction. Numerical simulations allow to assess the human-FAD interaction. An experiment is performed with a laboratory prototype, where a human operator lifts a load. It is observed that the human machine interaction is stable and the human operator is able to move the load to its desired position by experiencing very little effort.}, }

@article{1033736jaspe4082018, title={Comparison of Control Algorithms Using a Generalized Model for a Human with an Exoskeleton}, author={Concha, Antonio and S{\'a}nchez, Francisco Emmanuel Gonz{\'a}lez and Velasco, Efrain Ram{\'\i}rez and S{\'a}nchez, Mart{\'\i}n and Gadi, Suresh Kumar}, journal={Journal of Applied Science \& Process Engineering}, volume={5}, number={1}, year={2018}, abstract = {This article presents a pictorial representation of a generalized model for a human interacting with an exoskeleton or a force-augmenting device. This model is used for comparing four different control schemes, which are: 1) Kazerooni's algorithm, 2) BLEEX's algorithm, 3) technique inspired by fictitious gain, and 4) Force control with velocity and position feedback. The hardware and software requirements for the presented control algorithms are also discussed.}, url={http://publisher.unimas.my/ojs/index.php/JASPE/article/view/408}, doi={10.33736/jaspe.408.2018}, pdf={http://publisher.unimas.my/ojs/index.php/JASPE/article/view/408/574}, }

@article{1033736jaspe4372017, title={Human Adaptation Towards a Force Augmenting Device: Experimental Results}, author={Gadi, SK and Osorio-Cordero, A and Lozano, Rogelio and Garrido, R}, journal={Journal of Applied Science \& Process Engineering}, volume={4}, number={2}, year={2017}, doi={10.33736/jaspe.437.2017}, url={http://publisher.unimas.my/ojs/index.php/JASPE/article/view/437}, pdf={http://publisher.unimas.my/ojs/index.php/JASPE/article/view/437/385}, abstract={This short communication article presents an experiment to test the existence of mental workload (MWL) and adaptability of a human operator (HO) in handling force augmenting devices (FADs). An experiment is conducted where the HOs of three different ages are allowed to handle a FAD with high augmentation factor. Augmentation factor gives the factor by which the HO's force is amplified. It is observed that the HOs were unable to stabilize the FAD for the first time. With the help of these experiments, it is observed that a human adapts itself to achieve a stable HA-FAD interaction. In another perspective, it can be observed that HO undergoes MWL to handle a FAD with high augmentation factor.}, }

@Article{103390sym10100461, AUTHOR = {Luviano-Cruz, David and Garcia-Luna, Francesco and Pérez-Domínguez, Luis and Gadi, S. K.}, TITLE = {Multi-Agent Reinforcement Learning Using Linear Fuzzy Model Applied to Cooperative Mobile Robots}, JOURNAL = {Symmetry}, VOLUME = {10}, YEAR = {2018}, NUMBER = {10}, ARTICLE-NUMBER = {461}, URL = {http://www.mdpi.com/2073-8994/10/10/461}, pdf = {https://res.mdpi.com/d_attachment/symmetry/symmetry-10-00461/article_deploy/symmetry-10-00461.pdf}, ISSN = {2073-8994}, ABSTRACT = {A multi-agent system (MAS) is suitable for addressing tasks in a variety of domains without any programmed behaviors, which makes it ideal for the problems associated with the mobile robots. Reinforcement learning (RL) is a successful approach used in the MASs to acquire new behaviors; most of these select exact Q-values in small discrete state space and action space. This article presents a joint Q-function linearly fuzzified for a MAS’ continuous state space, which overcomes the dimensionality problem. Also, this article gives a proof for the convergence and existence of the solution proposed by the algorithm presented. This article also discusses the numerical simulations and experimental results that were carried out to validate the proposed algorithm.}, DOI = {10.3390/sym10100461} gsktype = "artJCR", }

@ARTICLE {2019aconchaskgadi, author = "A. Concha and S. K. Gadi", title = "Multifactorial Experiment Simulator: An Android App to Teach The Experimental Design", journal = "International Journal of Advances in Science Engineering and Technology", year = "2019", volume = "7", number = "Spl. Issue-2", pages = "28--31", month = "mar", abstract = "This article presents the problems associated in generating examples for the experimental design. The android app Multifactorial Experiment Simulator (MES) is presented in this document which simulates a multi-factorial process. This app can be used by an individual or by a teacher in a classroom to learn or teach the optimization techniques in the area of experimental design. Also, an example of finding optimal parameters is presented.", keywords = {Experimental Design, Experiment Simulator, Android App}, pdf = {http://ijaseat.iraj.in/paper_detail.php?paper_id=15315}, url = {http://www.iraj.in/journal/journal_file/journal_pdf/6-553-156051668128-31.pdf}, }

@article{2019conchaandroid, author = {Concha, A and Luna-Ochoa, CM and Vejar, Set and Gadi, SK}, title = {An android application for system identification and automatic control}, booktitle={Memorias del Congreso Nacional de Control Automático}, year={2019}, pages={600--605}, abstract={This paper proposes a novel Android application, named Control and Identification Toolbox (CIT), for performing real-time experiments of system response, automatic control, and parameter identification of dynamic systems. It permits tuning a traditional Proportional Integral Derivative controller (PID), whose performance under constant or noise disturbances, introduced by the app, can be analyzed during the experiments. Moreover, this app allows estimating the parameters of first- and second-order linear systems by means of the Recursive Least Squares Method. The parameter estimates, as well as control system signals produced under common test input signals are displayed by the app. It runs in any Android device supporting a universal serial bus (USB), which is connected with Arduino Uno or Mega boards that carry out data acquisition. Experimental results obtained using a physical circuit, composed by a first-order low-pass filter, confirm the effectiveness of the proposed application.}, keywords={Android application, real-time experiments, system response, parameter identification, automatic control}, month=oct, url = {http://www.amca.mx/RevistaDigital/cnca2019/files/0065.pdf}, eprint = {http://www.amca.mx/RevistaDigital/cnca2019/files/0065.pdf}, pdf = {http://www.amca.mx/RevistaDigital/cnca2019/files/0065.pdf} }

@inbook{9788478347919, author = {Inty Omar Hernández De Lira and Lilia E Montañez Hernández and Adriana López and Antonio Rodríguez Martínez Villanueva and Suresh Kumar Gadi and Nagamani Balagurusamy}, editor = {Helena Cabal Cuesta and Efraín Gómez Arias and Antonio Rodríguez Martínez}, title = {Perspectivas de Sustentabilidad en México}, chapter = {Avances, Retos y Perspectivas de Bioenergía en México}, pages = {69-81}, publisher = {Editorial Ciemat}, year = 2017, address = {Avda. Complutense, 40, 28040-Madrid}, edition = 1, month = 12, isbn = {978-84-7834-791-9}, abstract = {El gobierno mexicano ha implementado una serie de reformas en busca de la promoción de energías limpias como la bioenergía, con el objetivo de alcanzar las metas propuestas para el año 2024, donde el 35% de la generación eléctrica provenga de energías limpias. La bioenergía en México representa el 4.22% del total de la generación de la electricidad en el país, destacando principalmente la tecnología del biogás y la quema de la biomasa directa a través del bagazo de caña de azúcar con 92 GWh y 986 MWh respectivamente. Los estados del país que tienen alto potencial de generación son el Estado de México, Coahuila y Jalisco, por otra parte, los estados con mayor generación eléctrica a partir de bioenergía son Veracruz, Jalisco y Nuevo León, con una suma total de 855 GWh por año. México cuenta con gran potencial para la generación de biocombustibles, sin embargo, es un área que no ha sido explotada satisfactoriamente. Cabe mencionar que el país no cuenta con refinerías para la producción de etanol y actualmente sólo se contabilizan 4 plantas de biodiesel. Los impactos medioambientales producto de la bioenergía en México, son poco estudiados, sin embargo, la aplicación del análisis de ciclo de vida permitirá evaluar las cargas ambientales de esta forma de generación de energía.}, }

@article{doi101002cae22145, author = {Concha, Antonio and Luviano-Cruz, David and Calderon, G. and Gadi, S. K.}, title = {Control and Identification Toolbox (CIT): An Android application for teaching automatic control and system identification}, journal = {Computer Applications in Engineering Education}, volume = {27}, number = {5}, pages = {1186-1201}, keywords = {Android application, automatic control, parameter identification, real-time experiments, system response}, doi = {10.1002/cae.22145}, url = {https://onlinelibrary.wiley.com/doi/abs/10.1002/cae.22145}, eprint = {https://onlinelibrary.wiley.com/doi/pdf/10.1002/cae.22145}, abstract = {This article presents a free Android application, named as Control and Identification Toolbox (CIT), for teaching and learning the system response, automatic control, and the parameter identification of dynamic systems. The CIT app performs real-time experiments and permits tuning a traditional proportional-integral-derivative controller, whose performance under constant or noise disturbances, introduced by the app, can be analyzed. Moreover, this app allows estimating the parameters of first- and second-order linear systems by means of the recursive least squares method. The parameter estimates as well as the control system signals produced under common test input signals are displayed by the app. It runs in any Android device supporting a universal serial bus, which is connected with Arduino Uno or Mega boards that carry out data acquisition. Experimental results obtained using first- and second-order low-pass filters confirm the effectiveness of the proposed application. Moreover, undergraduate students evaluated the CIT app, and their responses are also presented.}, year = {2019}, }

@thesis{Gadi2009a, type = {mathesis}, gskthesislevel = "Master's", author = {S. K. Gadi}, title = {{Design of Factory Floor Tester for {HVAC} Controller and Remote Monitoring Unit}}, school = {VIT University}, year = {2009}, month = jun, pdf = {https://drive.google.com/file/d/0B6A_I6W9HjBDN0ZfQ3BtZGVhNVE/view}, abstract = {In a factory, final product needs to be thoroughly inspected before delivering to customer. This is achieved by factory floor tester. Factory floor tester is responsible for automation of testing final product's completeness, assembly exactness and correct functionality. The project deals with design of the factory floor tester. This includes the hardware design, software design, integration of software with fabricated hardware and testing the whole setup. Hardware design includes the design of electronic circuit and simulation. Software design is development of a GUI interface to the designed hardware. This includes the coding in embedded C, embedded C++ and Visual C++. The software code and other data is dumped in the fabricated unit's memory, the unit is allowed to interface with the PC for the GUI module to take control over it. The final phase is to test and debug the software to assure the proper integration between both software and hardware setup. The advancement of virtual instrument allows us to perform more complex testing operations. This project also deals with developing an test equipment which is responsible of testing complex functionalities like GSM communication (multi threading operations), handling multiple grounds effectively (implementing complex algorithms), connecting database and making database available for analysis (manipulating database over network). Identifying the System transfer function gives the detail information of the system. In this project we have attempted to automate the process of identifying the transfer function of an electrical system.}, }

@thesis{Gadi2014a, type = {phdthesis}, gskthesislevel = "PhD", author = {S. K. Gadi}, title = {{Modelado y Control de un Dispositivo de Aumento de Fuerza}}, school = {Centro de Investigaci{\'o}n y de Estudios Avanzados del Instituto Polit{\'e}cnico Nacional (CINVESTAV-IPN)}, year = {2014}, month = may, pdf={https://drive.google.com/file/d/0B6A_I6W9HjBDWTd0SVZETTZuaFU/view}, abstract = {This thesis presents a one degree of freedom (DOF) linear force augmenting device (FAD), a human arm (HA) model, a model of the FAD-HA interaction, a stability analysis for the system resulting from the FAD-HA interaction, and finally numerical simulations and experimental results. The FAD consists of an electrical motor and a ball-screw mechanism that converts the torque generated by the electric motor to a force that moves a load. A force sensor is attached to the load to capture the force applied by the human operator to the FAD. The control algorithm presented in this thesis allows the user to feel part of the load all the time, even at the rest position. A linear model for the HA is employed to study the stability of the FAD-HA interaction. As a depart from past works, this work presents a stability analysis considering time-delays in the human model. A key ingredient in the analysis is the use of the Rekasius substitution for replacing the time-delay terms. It is proved that the FAD-HA interaction is stable when the human model has no delays. When delays are considered in the human model, the analysis performed provides upper bounds for the time-delays below which a stable interaction is assured. Numerical simulations are presented, which allow assessing the FAD-HA interaction. Experimentation is performed with a laboratory prototype with which several human operators lift a load. It is observed that the FAD-HA interaction is stable and that the human operator is able to lift the load to its desired position by experiencing an effort that can always be controlled.}, }