My research is summareized in a nutshell on this page. You can find more details about the individual projects under the Research Projects tab on the left menu.

Data-driven micro-climate control in smart buildings:

My recent post-doctoral research work focuses on designing adaptive, data-driven controllers for heating, ventilation, and air-condintioning (HVAC) systems in buildings to simultaneously reduce energy usage and improve occupants' comfort.  This multi-objective control problem is formulated as a semi-Markov decision process (SMDP) and is solved in a reinforcement learning set-up where the controller does not have access to the building model. Leveraging the domain knowledge as well as the SMDP formulation, I designed learning control algorithms that are both data- and computationally efficient, and hence suitable for real-world applications. In view of our novel methodology, we designed a smart thermostat that can learn how to operate optimally in just about a week.

Nonlinear dynamics and structural instabilities for vibration energy harvesting:

My doctoral work focuses on fundamental power limits and robustness issues in nonlinear vibratory energy harvesters (VEHs). I developed a general framework for calculation of these limits for arbitrary excitation and constraints . As a byproduct of this analysis, I characterized a universal, nonlinear optimal law (buy-low-sell-high strategy) that maximizes the harvested power and proposed practical implementation methods by employing intentional nonlinearities. This strategy is able to explain the high effectiveness of the extensively-studied bistable as well as other multi-stable harvesters. To address the robustness issues of VEHs, I proposed a new optimization philosophy for passive harvesters and a novel sliding mode controller for active variants that could successfully move the harvester to any desired attractor in the presence of uncertainties. Furthermore, I postulated the idea of using large-strain structural instabilities, such as, wrinkling for effective energy harvesting.

Structural vibration analysis and control:

Part of my past research focused on system modeling, and vibration analysis and protection of devices/machines with sensitive internal components in harsh environmental conditions. These projects include: 

• system modeling, and shock and random vibration protection of liquid-cooled (via jet-impingement) electronics 
• shock and vibration control of Humvees using semi-active suspension
• high-velocity impact analysis and ruggedization of communication transponders
• mathematical modeling, and shock and vibration protection of proton exchange membrane fuel cells (PEMFCs) for transportation industry
• vibration analysis and protection system design for laptop computers 
• modeling of tire-soil interaction in agricultural machinery 
• bridge vibration analysis and control under dynamic vehicular load