Moderator:
Alex Slocum, PhD, Pappalardo Professor of Mechanical
Engineering MacVicar Faculty Fellow, MIT, slocum@mit.edu
Bio-Inspired Robot Design
with Compliant Mechanism Fabrication
Sangbae Kim, PhD, Post-doctorate fellow, Micro-robotics
Laboratory, Harvard University, sangbae@mit.edu
Mobile robot designers are increasingly
searching for inspiration and design cues from biological models. Biomechanical
studies on running animals underscore the importance of the passive
properties of muscles, tendons, and other elements of the musculoskeletal
system. These elements play significant roles in self-stabilization
and elastic energy storage, resulting in smoother and more efficient
performance in natural environments. Through abstraction and simplification
of biological inspiration, fundamental design principles are embodied
in a number of bio-inspired robots. To demonstrate this process, the
core design features of three legged robots are described, focusing
on compliant under-actuated mechanism made by multi-material manufacturing
process called shape deposition manufacturing. The first bio-inspired
robot is iSprawl, a cockroach-inspired hexapod with compliant, under-actuated
legs. Its passive hip joints and a light and flexible push-pull cable
transmission allow it to run at 15 body-lengths per second. The second
robot is Spinybot, a hexapod that uses its toes with microspines to
climb rough surfaces, including stucco, concrete and brick walls. The
last robot is Stickybot, a gecko-inspired quadruped that climbs smooth
vertical surfaces using directional dry adhesion. Stickybot contains
several types of under-actuated mechanisms in its body, legs and toes.
At the smallest length scale, the undersides of the toes are covered
with a unique material called directional polymeric stalk (DPS), inspired
by the directional setae and lamellae of the gecko. The future direction
of Sangbae Kim's research involves several design principles toward
bio-inspired robots and a novel manufacturing technology that enables
hybrid structures combining multiple materials, including multi-grade
elastomeric/solid materials, liquid, and gas with embedded sensors and
actuators.
Fluidic Logic_-
Merging Chemistry and Computation with Microfluidics
Manu Prakesh, PhD, Elected Junior Fellow (Physics),
Harvard Society of Fellows; Visiting Scholar, MIT, manup@mit.edu
Starting from genetic blueprints,
biological materials turn into complex, multi-compartmental "living"
things with algorithmic precision. One fundamental difference between
biological and physical materials is their inherent computational ability.
Though we have long understood that "Information representation
is invariably physical", we are only now beginning to exploit this
insight to shape, program and manipulate matter in engineered systems.
Manu Prakesh will introduce a paradigm in computation where bits can
simultaneously transport and manipulate both materials and information,
similar to how integrated circuits allow us to control the flow of electrons.
He will describe an entirely new digital logic family which implements
universal Boolean logic in an all-fluidic system, exploiting purely
hydrodynamic nonlinearities in low-Reynolds number two-phase flow. Such
a physical implementation thus provides a flow control mechanism for
sub-nanoliter droplets operating at KHz frequencies with no moving parts.
A "lego-set" like toolbox comprising of microfluidic circuits
including AND/OR/NOT gates, flip-flops, counters, ring-oscillators and
synchronizers will be introduced. These show the nonlinearity, gain,
bistability, synchronization, cascadability, feedback and programmability
required for scalable universal computation and all-fluidic control.
This platform technology represents initial steps towards modular design
of sub-nanoliter droplet reactors with applications in high throughput
screening for novel materials, combinatorial chemistry and implanted
devices.
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