Mechanical Engineering-Engineering Mechanics News

The ME-EM Graduate Seminar speaker on Thursday, September 10 at 4:00 in 103 EERC will be Dr. Brandon Dilworth from MIT Lincoln Laboratory.

The title of his presentation will be ‘LLCD Experimental Line-of-Sight Jitter Testing’.

The Lunar Laser Communication Demonstration (LLCD) program at MIT Lincoln Laboratory is the first space laser commu-nication system for NASA. The optical communications terminal will be carried into lunar orbit by the Lunar Atmosphere and Dust Environment Explorer (LADEE) spacecraft which launched on September 6, 2013. The primary goal of the LLCD program is to demonstrate optical communication from lunar orbit to the Earth’s surface.

Optical communication systems have many advantages over radio frequency (RF) systems which include achieving higher data rates using lower size, weight and power (SWaP). Optical communication systems rely on much narrower beams than RF systems to achieve these advantages; the penalty is that the optical beam must have good stability in order to maintain the communication link between the transmitter and receiver. There are a number of factors that play a role in the stability of the optical beam, but the focus of this talk is on the residual line-of-sight (LOS) jitter resulting from unrejected spacecraft excitation.

During early program development mathematical analyses, starting from simple hand calculations and evolving through complex computational techniques, are used to drive the design. As with any type of analytical analyses, many assumptions are used to identify different characteristics of the system. As programs develop, these mathematical models are used to drive the design so there is a strong desire to validate these models as the design continues to mature. Experimentation with physical hardware is a common method for validating mathematical models, including residual LOS jitter models. The LLCD program developed a test bench in order to validate the residual LOS jitter model which provides higher confidence in the computational results.

This presentation will provide an overview of the LLCD program, summarize some of the components of the Optical Module and to describe the efforts behind validating the residual LOS jitter model using experimental techniques.
This work is sponsored by the National Aeronautics and Space Administration under Air Force Contract #FA8721-05-C-0002. Opinions, interpretations, conclusions and recommendations are those of the author and are not necessarily endorsed by the United States Government.

I graduated from Michigan Tech with Master’s in 2006 and PhD in 2009 working in the Dynamic Systems Lab under Jason Blough. My focus was on structural dynamics and acoustics with heavy emphasis on experimental techniques and signal processing.

I started working at MIT Lincoln Laboratory immediately after graduation from Tech in 2009 as part of the Mechanical Engineering Group within the Engineering Division. My first pro-gram involvement at Lincoln was on the Lunar Laser Communication Demonstration (LLCD) program sponsored by NASA – which some of the work is highlighted during this seminar. For the LLCD program, I worked as a unit lead/design engineer and as a test development engineer. Since the successful completion of LLCD, my primary efforts have been as the Lead Engineer of a ground terminal for generic free space laser communication diagnostics.

My design efforts on LLCD were recognized with two Group merit awards in 2011. I received the Division Early Career Award in 2012. The LLCD team received the Laboratory Team Award in 2013. I was also part of a team investigating a short-term, high visibility effort which received the MIT Excellence Award in 2015. I currently sit on the Advanced Concepts Committee within Lincoln which focuses on development of new and novel technologies of national interest.

The ME-EM Graduate Seminar speaker on Thursday, September 3 at 4:00 in 103 EERC will be Dr. Wangda Zuo from the University of Miami.

The title of his presentation will be ‘Equation-Based Modeling and Simulations for Sustainable Buildings’.

Buildings account for about 41% of energy consumption, 10% of water consumption and 39% of CO2 emission in the U.S. To enable the design and operation of sustainable buildings, building system solutions need to adapt to the local availability of sources and sinks for thermal conditioning, ventilation, lighting, electricity production and water collection, while respecting constraints for occupant health and comfort, building service levels, building system maintainability and aesthetic considerations. As a result, the building becomes an integrated system of multi-physics, multi-scale heterogeneous subsystems. The underlying equations are nonlinear systems of ordinary differential equations, partial differential equations and algebraic equations with continuous and discrete time, as well as control events. Modeling, simulation and analysis of such systems pose new challenges as systems become increasingly integrated. This presentation introduces some of our recent research in developing and applying Modelica-based simulation technology for the design, operation and optimization of sustainable buildings. Modelica is an equation-based object-oriented modeling language for dynamic systems. With the support of US Department of Energy, we developed an open source Modelica Buildings library for building energy and control systems. We will briefly discuss the fundamental challenges in modeling the building systems using the equation-based language. We will also demonstrate the usage of Modelica-based technology in real world research projects. Finally, we will discuss our research initiatives in urban scale simulation.

Dr. Wangda Zuo is an Assistant Professor at the University of Miami. His research focuses on developing and applying innovative physical models and simulation technology for sustainable building systems. He is the Research Committee Chair of International Building Performance Simulation Association (IBPSA) – USA Chapter, Voting Member of American Society of Heating Refrigeration and Air-Conditioning Engineering (ASHRAE) Technical Committee 4.7, 4.10 and 7.4. Before joining the University of Miami, Dr. Zuo was a Research Scientist at the DOE’s Lawrence Berkeley National Laboratory. Dr. Zuo received his Ph.D. in Mechanical Engineering from Purdue University, M.S. in Computational Engineering from the University of Erlangen and Nuremberg in Germany, M. Eng and B.S. in Automation from Chongqing University in China.