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Symposia
A DISCUSSION ABOUT CAE-BASED METHODS FOR ANALYZING
AND DESIGNING SPATIAL COMPLIANT MECHANISMS
Giovanni Berselli
DIME - Department of Mechanical, Energy,
Management and Transportation Engineering
University of Genova, Italy
Abstract
Compliant Mechanisms (CMs) and Mechatronic Systems formed therewith
are currently employed in several engineering applications requiring high
precision and reduced number of parts. For a given mechanism topology,
CM analysis and synthesis may be developed resorting to several
methods, here including the well-known Pseudo-Rigid Body (PRB)
approximation, where flexible members undergoing large deformations
are modelled via a series of spring-loaded revolute joints. The PRB
approach is not only intended as a design tool for the first attempt sizing of
the mechanism, but it is also useful for reducing computational costs
during simulation and control of engineering systems containing compliant WHY MORPH?
members. In particular, from a CM analysis standpoint, the applicability of
a generic PRB model requires the determination of the kinematic pairs’
location and the stiffness of a set of generalized springs. In parallel, from a
design standpoint, a PRB model representing the kinetostatic behavior of
a flexible system should allow to determine the flexures’ characteristics
providing the desired compliance. In light of these considerations, the
objective of the present talk is to critically discuss, on the basis of our
experience, engineering methods and related CAD/CAE tools allowing for
the automatic computation of accurate PRB model parameters and for the
shape optimization of complex-shaped flexures comprising out-of-plane
displacements and distributed compliance. The proposed procedure
leverages on the simulation capabilities of modern parametric CAE
packages, which provide built-in functions for modelling the motion of
flexible members and can be interfaced with external optimizers. After a
brief overview of current and past projects, few case studies are briefly
discussed, namely: 1) a fully-compliant four bar linkage comprising flexures
with non-trivial shape affected by out-of-plane motions; 2) a compliant
RCC device for pin insertion, whose aim is to test the method also in
presence of contacts between parts; 3) a smart-actuated monolithic
compliant clutch, for application on switching Variable Stiffness Actuators functional and ii) can be easily integrated in the aircraft structure. While
for safe human-machine interaction. The proposed simulation technique,
which combines reliable numerical results to the visual insight of CAD/CAE technology transition with demonstrated performance improvements has
tools, may be particularly useful for analysing/designing spatial CMs
composed of complex flexure topologies.
Biography
Giovanni Berselli is Associate Professor in Design Methods and Tools for
Industrial Engineering at the University of Genova, Italy, where he teaches
the courses of Design of Automatic Machines and Computer Aided
Design. He was previously Visiting Professor with the Robotics and
Mechatronics (RAM) Lab of the University of Twente, The Netherlands, and
18 also Research Associate with Monash University, Australia, and with the
University of Navarra, Spain. Prof. Berselli has been involved in several
European projects and contracts with private companies (e.g. WP Leader
for the EU project AREUS - Automation and Robotics for EUropean
Sustainabile manufacturing, Task Leader for the project ADAPTIVE
- Technology Cluster “Intelligent Factory”). He has authored more than 130
publications in peer-reviewed international scientific journals and
conference proceedings, and he has been Editor of one international
book, recipient of an IEEE I-RAS Young Author and an IFToMM Best Paper
Awards, invited speaker in several international research institution or
universities, and finalist for an ERC starting grant in 2016. Prof. Berselli’s
scientific activity is strongly focused on the development of engineering
methods and tools for the conceptual design, the modelling and
optimisation, and the experimental evaluation of innovative mechanical/
mechatronic systems (especially automatic machines). Specific examples
are: i) Compliant mechanisms and smart-material-based transducers for
safe and effective human-machine and environment-machine interaction;
ii) Virtual Prototyping of Automatic Machines with focus on energy-aware
design methods for sustainable & green automation.
SYMPOSIUM 4
Jayanth N. Kudva
NextGen Aeronautics, Inc.
Torrance, CA
Abstract
Morphing, i.e., changing the shape (or more generally the state) of an
aircraft has been a major focus of the smart materials and structures R&D
community for more than two decades. The overarching goal is to provide
multi-point optimization at the system level, for example to realize wing
shapes which could be optimal across a wide speed range, potentially
enabling development of aircraft which are ultra-efficient and have
multi-mission capabilities.
Key and critical technology enablers are materials which are: i) multi-
much fundamental and applied research has been conducted in this area,
been limited. The reasons for this are many and varied; this talk will
discuss the rationale for morphing aircraft designs, potential benefits and
costs, technology and operational limitations, and thoughts on the future
course of smart materials technology development. The talk will also
explore related and complementary technologies including health
monitoring and structurally integrated antenna structures which would
have synergistic benefits at the system level for development of
continuously optimal and operationally flexible aircraft.