My doctoral work at IIT Delhi was in the broad area of Robust Control. After a short stint with simulation studies using Neural Networks and Fuzzy Logic, I preferred to switch over to a more rigorous approach of applying game theory to control problems in nonlinear systems. I succeeded in my attempt to integrate the measures of robustness (the H∞-norm), and intelligence (the reinforcement learning), in the game theoretic setting. I am proud to say that this work was conceived and conceptualized more than a decade ahead of the current software packages and sundry applications in deep neural networks and reinforcement learning.
Dynamic Programming was an integral part of my thesis and working extensively on this goaded me to look at the “computational” issues. Soon after my thesis, I started looking at the controller design problems from a computational complexity point of view and discovered certain interesting issues; for instance, the pole placement problem (full state feedback control) in linear systems with constraints is NP hard (it may take ages to arrive at a satisfactory design), and the complexity of simple and the most popular output feedback control problem is unknown. This problem is still in the list of open problems in Systems & Control. Complexity theory provides a rigorous mathematical framework to study such problems and prompts us to invent computationally tractable algorithms. This line of research is very pragmatic since computation is now regarded as an equal and indispensable partner along with theory and experiment in engineering practice. In the year 2001 I was invited to visit the Institute of Mathematical Sciences Chennai, as an associate professor. This institute has provided facilities for my carrying out this research for three years. Towards late 2002, the Department of Science & Technology (DST, GoI) has approved my proposal for further research in this direction on a larger scale and funded me under its Young Scientists scheme. Since then I have been working towards developing computationally efficient control algorithms. This bringing together control systems and complexity theory of computer science is has been scintillating, and all of my learning and current research has been pivoted on this.
In May 1996 I joined the National Institute of Technology at Tiruchirappalli as a lecturer in the fledgling department of Instrumentation and Control Engineering. Owing to the wider spectrum of courses offered here, I was assigned to devise the “Control Stream” with core courses - Mathematics, Network Theory, Signals and Systems, Microelectronics, Operational Amplifiers, Control Systems, Data Structures and Algorithms, and Modern Control Theory (in that order, semester-wise), and related electives like Robotics, Nonlinear Control, Automotive Control Systems, Intelligent Control, Computational Techniques in Control Engg., Probability & Computing, and Cooperative Control. Most of these courses are regularly offered by me. I also had an opportunity to be the founder-convener for the department's library and the computer center.
Over the years this stream has evolved quiet well with a rich blend of mathematical rigor and physical intuition. I have also developed four core laboratories, primarily for the undergraduate students, where low cost electrical network elements and hands-on experimentation are preferred to expensive demonstration modules. One of the interesting experiments is the non-inverting Deboo Integrator during V and VI semesters. This practice has been well received since it enables the student to apply the theory verbatim and conduct an experiment rather than simply demonstrate. There are several masters' and doctoral students who work in these laboratories for enriching their fundamentals. Using the resources of these laboratories I guide students in designing and developing low-cost self-navigating mobile robots. For the Robotics & Machine Intelligence (RMI) club under the IEEE student chapter, I have guided several projects, including an all-terrain vehicle, self-balancing bicycle, and a virtual xylophone. These activities have been much sought after in the campus, motivating several students into pursuing research in the USA, the UK, and Australia. In turn this motivates me to nurture the student community here. I have summarized my experiences, partly in teaching and partly in research, and authored two textbooks titled Control Engineering: A Comprehensive Foundation and Linear Circuits: Analysis and Synthesis.
Post 2005, NIT Tiruchirappalli added research to its otherwise teaching agenda. Continuing with my research in computational complexity for practical control systems, I have collaborated with the Dept. of Aerospace Engg., Indian Institute of Science Bangalore in 2007. Our joint proposal “Towards Reliable Smart and Adaptable Air-Vehicles” was granted major award by the British Council under its maiden UKIERI scheme 2007-11. This was one of the 7 proposals (among sciences, engineering, medicine and so on), and the only NIT, to get this major grant. In addition to IISc Bangalore, I had an opportunity to work closely with the research groups at the University of Leicester (UK), IIT Bombay, and National Aerospace Laboratories (NAL) Bangalore. In particular, I contributed to the design and analysis of path planning algorithms for UAVs and certain on-board electronics for mini and micro air-vehicles. As a part of this project I guided a PhD in the broad area of Networked Control Systems. This was my getting into the field of cyber-physical systems. A couple of months ago a student of mine got her Ph.D. from our institute for her work on Graph Theoretic Modeling and Control of Decongesting Traffic Networks wherein we tapped on V2V and V2I communications and developed a robust framework for the design of very large intersections.
During January-March 2013, I conducted a Certificate Course in Advanced Control Engineering for the scientists at DRDL Hyderabad, with topics such as State-space controller design, Optimal Control & Dynamic Programming, Computational Techniques, and Kalman Filters, tailored to their research activities. Subsequently, one of the senior scientists of the organization worked on these ideas extensively and submitted his PhD thesis on Modern Control Laws for a class of Missile Systems to our institute under my supervision.
In summary, all through I have been quite proactive in the academic activities, albeit an initial emphasis on undergraduate teaching, pertinent to my parent institution. I strengthened myself in peer-networking over years. I have healthy professional relationship with several universities around the world, as well as with the industry – ABB, NAL, BHEL, DRDO, to name a few.
During 2019, I was invited to deliver a talk “A Fresh Approach to Teaching State-Space Methods in an Undergraduate Course” at the prestigious 12th IFAC Symposium on Advances in Control Education (IFAC-ACE 2019), July 7 – 9, 2019, Philadelphia, USA. Recently I have co-authored a huge reference book Control Systems: Classical, Modern, and AI based Approaches, covering the gamut of control and this is published later in 2019 by the Taylor & Francis group, CRC Press, USA.
All along, in the 25+ years of my service here, there was no compromise on the quality of education I have imparted to the students, both undergraduate and graduate. It has been a source of deep inspiration and immense satisfaction receiving periodic mails of appreciation from my passed-out students who stand witness to my mentoring. I look forward to taking up more exciting projects both in theory and in practice that would enrich my learning, and consequently allow me to work for the welfare and growth of the society around me.
