Page 76 - ASME DSCC 2015 Program

Technical Program

Mathematical Model for Coordinated Motion of Modular Mechatronic Modeling of flexible Structures by Means of Least Square Support
Device (MechaCells) Vector Machine
Contributed regular paper. DSCC2015-9896 Contributed regular paper. DSCC2015-9673
Stefan Ristevski, Melih Cakmakci, Bilkent University, Ankara, Turkey hammam Tamimi, dirk Söffker, University of Duisburg-Essen, Duisburg,
Germany
Manufacturing techniques have advanced exponentially in recent years,
providing means for micro even nano scale manufacturing of different This paper investigates modeling of flexible structures by means of the
structures. Mechanical and electrical components are being manufactured least squares support vector machine (LS-SVM) algorithm. Modeling is the
at micro/nano scale, producing amazing opportunity in micro/nano modular first step to obtain a suitable model-based controller for any given system.
robot development, modules that are smaller and more powerful. Develop- Accurate modeling of a flexible structures based on experimental data using
ment of mathematical models for such modular devices has an important LS-SVM algorithm requires less knowledge about the physical system. Least
role in the design and development of control strategies for coordinated squares support vector machine algorithm can achieve global and unique
movement. Our work focuses on developing a mathematical model for a solution when compared with other soft computing algorithms. Also, LS-SVM
modular mechatronic device, MechaCell. In the mathematical model inter- algorithm requires less training time. In this paper, the successful use of sup-
action forces module—workpiece are modeled as noise to the system and port vector machine algorithm to model the flexible cantilever is provided.
are compensated with a closed loop controller. Experiments with an actual The acquired model is able to provide accurate prediction of the system
workpiece are conducted and experimental data fits to the simulation data. output under different operating conditions. Experimental results demon-
Our future work will include development of better control strategies for strate the efficiency and high precision of the proposed approach
coordinated motion and object transportation and caging stratifies. Thermal Model of fuse Dynamics for Simulation under Intermittent DC
a Model of Liquid-drop Spreading for electrohydrodynamic jet printing faults
Contributed regular paper. DSCC2015-9995 Contributed regular paper. DSCC2015-9815
Christopher Pannier, Kira Barton, University of Michigan, Ann Arbor, MI, Bharatkumar Hegde, Shawn Midlam-Mohler, Punit Tulpule, The Ohio
United States, David Hoelzle, Zhi Wang, University of Notre Dame, Notre State University, Columbus, OH, United States
Dame, IN, United States
Thermal Model of Fuse Dynamics for Simulation under Intermittent DC Faults
Electrohydrodynamic jet (E-jet) printing is a recent technique for high reso- Modulation of nonlinear Hydrodynamic Damping in finite Amplitude
lution additive micromanufacturing. With high resolution comes sensitivity to underwater oscillations of flanged Structures
small disturbances, which has kept this technique from reaching its industrial
Contributed regular paper. DSCC2015-9778
potential. Closed loop control of E-jet printing can overcome these distur-
Syed n. Ahsan, Matteo Aureli, University of Nevada, Reno, Reno, NV,
bances, but it requires an improved understanding of ink droplet spreading
United States
on the substrate and a physical model to predict printed feature locations
and geometries from process inputs and disturbances. This manuscript In this paper, we study the fluid-structure interaction problem of the harmon-
examines a model of ink droplet spreading that uses assumptions that ic oscillations of a flanged lamina in a quiescent, Newtonian, viscous fluid.
are important to the e-jet process. Our model leverages previous energy Here, the flanges are introduced to elicit specific vortex-structure inter-
balance models that were derived for larger length scale droplets. At the actions, with the ultimate goal of modulating the nonlinear hydrodynamic
smaller length scale, we find that viscous losses are a significant portion of damping experienced by the oscillating structure. The hydrodynamic forc-
the energy budget and must be accounted for; this is in contrast to models ing, incorporating added mass and hydrodynamic damping effects, is eval-
at length scales two orders of magnitude larger. Our model predicts the uated through boundary element method and computational fluid dynamics
droplet height, base radius and contact angle in time from an initial volume simulations. This allows to identify a model for the hydrodynamic forces in
and E-jet printing control parameters. The model is validated with published the form of a complex-valued function of three nondimensional parameters,
droplet spreading data and new measurements of E-jet-printed droplets of describing oscillation frequency and amplitude and flange size. We find that
diameter 8 micrometers. The viscous friction calculated in the new model is the presence of the flanges results into larger fluid entrainment during the
found to be significant compared to surface energy. lamina oscillation, thus affecting the added mass. Further, we highlight the
existence of a minimum in the hydrodynamic damping which is governed by
complex dynamics of vortex-structure interaction. This peculiar phenomenon
is discussed from physical grounds by analysis of the pertinent hydrodynam-
ic fields. Finally, we propose a tractable form for the hydrodynamic function,
to be used in the study of large amplitude underwater flexural vibrations of
flanged structures.

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