BIOLOGICALLY INSPIRED INTELLIGENT ROBOTS USING
ARTIFICIAL MUSCLE
Artificial
Intelligence is a branch of Science
which deals with helping machines finds solutions to complex problems in a more
human-like fashion. This generally involves borrowing characteristics from
human intelligence, and applying them as algorithms in a computer friendly way.
A more or less flexible or efficient approach can be taken depending on the
requirements established, which influences how artificial the intelligent
behavior appears.
Humans throughout history have
always sought to mimic the appearance, mobility, functionality, intelligent
operation, and thinking process of biological creatures. This field of
biologically inspired technology, having the moniker biometrics, has evolved
from making static copies of human and animals in the form of statues to the
emergence of robots that operate with realistic appearance and behavior. This
paper covers the current state-of-the-art and challenges to making biomimetic
robots using artificial muscles.
Introduction:
AI
is generally associated with Computer
Science, but it has many important links with other fields such as Math’s, Psychology, Cognition,
Biology and Philosophy, among many others. The
ability to combine knowledge from all these fields will ultimately benefit the
progress in the quest of creating an intelligent artificial being. Advances in medicine have led to the
availability of artificial blood, replacement
joints, heart valves, and heart-lung machines that are common implanted. device.
Muscle is a critically needed organ and its availability in an artificial form
for medical use can greatly contribute to the improvement of the quality of
life of many humans. Thus these electroactive polymers (EAP) that are also
known as artificial muscles can potentially address this need. These materials
are human made actuators that have the closest operation similarity to
biological muscles.
Motivation of Artificial Intelligence:
Computers
are fundamentally well suited to performing mechanical computations, using
fixed programmed rules. This allows artificial machines to perform simple
monotonous tasks efficiently and reliably, which humans are ill-suited to. For
more complex problems, things get more difficult... Unlike humans, computers
have trouble understanding specific situations, and adapting to new situations.
Artificial Intelligence aims to improve machine behavior in tackling such complex
tasks.
Technology:
There
are many different approaches to Artificial Intelligence, some are obviously
more suited than others in some cases, but any working alternative can be
defended. Over the years, trends have emerged based on the state of mind of
influential researchers, funding opportunities as well as available computer
hardware.
Artificial life through robotics:
Laws of Robotics:
1. A robot may not injure a
human being or, through inaction, allow a human being to come to harm.
2. A robot must obey the
orders given it by human beings except where such orders would conflict with
the first law.
3. A robot must protect its
own existence as long as such protection does not conflict with the first or
second law.
Robotics has been an evolution of the field of automation
where there was a desire to emulate biologically inspired characteristics of
manipulation and mobility. In recent years, significant advances have been made
in robotics, artificial intelligence and others fields allowing to make
sophisticate biologically inspired robots [Bar-Cohen and Brea zeal.
Biologically inspired robotics is a subset of the interdisciplinary field of
biomimetics. Technology progress resulted in machines that can recognize facial
expressions, understand speech, and perform mobility very similar to living
creatures including walking, hopping, and swimming. Further, advances in
polymer sciences led to the emergence of artificial muscles using Electro
active Polymer (EAP) materials that show functional characteristics remarkably
similar to biological muscles. Making
creatures that behave like the biological model is a standard procedure for the
animatronics industry that is quite well graphically animates the appearance
and behavior of such creatures. However, engineering such biomimetic
intelligent creatures as realistic robots is still challenge due to the need to
physical and technological constraints.
Artificial muscles:
Muscles are the key to the
mobility and manipulation capability of biological creatures and when creating
biomimetic it is essential to create actuators that emulate muscles. The
potential to make such actuators is increasingly becoming feasible with the
emergence of the electro active polymers (EAP), which are also known as
artificial muscles [Bar-Cohen, 2001]. These materials have functional
similarities to biological muscles, including resilience, damage tolerance, and
large actuation strains. Moreover, these materials can be used to make
mechanical devices with no traditional components like gears, and bearings,
which are responsible to their high costs, weight and premature failures. The
large displacement that can be obtained with EAP using low mass, low power and,
in some of these materials also low voltage, makes them attractive actuators.
The capability of EAPs to emulate muscles offers robotic capabilities that have
been in the realm of science fiction when relying on existing actuators.
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FIGURE
1: A graphic illustration of the grand
challenge for the development of EAP actuated robotics – an arm wrestling match
against human.
Unfortunately, the EAP materials
that have been developed so far are still exhibiting low conversion efficiency,
are not robust, and there are no standard commercial materials available for
consideration in practical applications. In order to be able to take these
materials from the development phase to application as effective actuators,
there is a need for an established infrastructure. For this purpose, it is
necessary to develop comprehensive understanding of EAP materials' behavior, as
well as effective processing, shaping and characterization techniques. The
technology of artificial muscles is still in its emerging stages but the
increased resources, the growing number of investigators conducting research
related to EAP, and the improved collaboration among developers, users, and
sponsors are leading to a rapid progress.
Robots, which could build other
robots, tried to protect humans from everything until people could not do
anything by themselves. Biggest supporters of AI research is military. One of
the reasons is that in "...a nuclear age, a new generation of very
intelligent computers incorporating AI could actually defend the country
better, faster, and more rationally than humans.
Biometric robots using EAP:
Mimicking nature would
significantly expand the functionality of robots allowing performance of tasks that are currently
impossible. As technology evolves, great number of biologically inspired robots
actuated by EAP materials emulating biological creatures is expected to emerge.
The challenges to making such robots can be seen graphically in Figure 2 where
humanlike and dog-like robots are shown to hop and express joy. Both tasks are
easy for humans and dogs to do but are extremely complex to perform by existing
robots.
FIGURE
2: Making a joyfully hopping human-like and
dog-like robots actuated by EAP materials are great challenges for biomimetic
robots
FIGURE
3: An android head and a robotic hand that are
serving as biomimetic platforms for the development of artificial muscles.
Categories of EAP:
EAP can be divided into two major categories based on their activation
mechanism including ionic and electronic. The electronic EAP are driven by
Coulomb forces and they include: Dielectric EAP (shown in Fig.4a),
Electrostrictive Graft Elastomers, Electrostrictive Paper, Electro-Viscoelastic
Elastomers, Ferroelectric Polymers and Liquid Crystal Elastomers (LCE). This
type of EAP materials can be made to hold the induced displacement while
activated under a DC voltage, allowing them to be considered forrobotic
applications. These materials have a greater mechanical energy density and they
can be operated in
air with no major constraints. However, the
electronic EAP require a high activation fields (>30-V/μm) that may be close
to the breakdown level. In contrast to the electronic EAP, ionic EAP are
materials that involve
mobility or diffusion of ions and they
consist of two electrodes and an electrolyte. The activation of the ionic EAP
can be made by as low as 1-2 Volts and mostly a bending displacement is
induced. The ionic
EAP include Carbon Nanotubes (CNT),
Conductive Polymers (CP), Electro Rheological Fluids (ERF), Ionic Polymer Gels
(IPG), and Ionic Polymer Metallic Composite (IPMC) (shown in Fig.4b). Their
disadvantages are the need to maintain wetness and they pose difficulties to
sustain constant displacement under activation of a DC voltage (except for
conductive polymers).
a. Dielectric EAP in relaxed (top) and
activated states (bottom)
b. IPMC in relaxed (left) and activated
states (right)
Examples of EAP materials in relaxed and
activated states.
The induced displacement of both the electronic and ionic EAP materials
can be designed geometrically to bend, stretch or contract. Any of the existing
EAP materials can be made to bend with a significant bending response, offering
an actuator with an easy to see reaction.
FIGURE4a. Dielectric EAP in relaxed (top) and
activated states (bottom).
FIGURE4b. IPMC in relaxed (left) and
activated states (right)
Making Robots Actuated by EAP:
Biomimetic intelligent creatures as
realistic robots were a significant challenge due to the physical and
technological constraints and shortcomings of existing technology. Making such
robots that can hop and land safely without risking damage to the mechanism, or
making body and facial expression of joy and excitement are very easy tasks for
human and animals to do but extremely complex to engineer. The use of
artificial intelligence, effective artificial muscles and other biomimetic
technologies are expected to make the possibility of realistically looking and
behaving robots into more practical engineering models. To promote the
development of effective EAP actuators, which could impact future robotics,
toys and animatronics, two test-bed platforms were developed. The conventional electric motors are
producing the required deformations to make relevant facial expressions of the
Android. Once effective EAP materials are chosen, they will be modelled into
the control system in terms of surface shape modifications and control
instructions for the creation of the desired facial expressions. Further, the
robotic hand is equipped with tandems and sensors for the operation of the
various joints mimicking human hand. The index finger of this hand is currently
being driven by conventional motors in order to establish a baseline and they
would be substituted by EAP when such materials are developed as effective
actuators. The growing availability of EAP materials that exhibit high
actuation displacements and forces is opening new avenues to bioengineering in
terms of medical devices and assistance to humans in overcoming different forms
of disability. Areas that are being considered include an angioplasty steering
mechanism, and rehabilitation robotics. For the latter, exoskeleton structures
are being considered to augment the mobility and functionalities of patients
with weak muscles.
Remote presence via
haptic interfaces:
Remotely operated robots and
simulators that involve virtual reality and the ability to “feel” remote or
virtual environment are highly attractive and offer unmatched capabilities
[Chapter 4 in Bar-Cohen and Brea zeal, 2003]. To address this need, the
engineering community are developing haptic (tactile and force) feedback systems that
are allowing users to immerse themselves in the display medium
while being connected thru haptic and
tactile interfaces to allow them to perform telepresence and “feel" at the
level of their fingers and toes. Recently, the potential of making such a
capability with high resolution and small workspace was enabled with the novel
MEMICA system (Mechanical Mirroring using Controlled stiffness and Actuators).
Biologically inspired
robots:
The evolution in capabilities
that are inspired by biology has increased to a level where more sophisticated
and demanding fields, such as space science, are considering the use of such
robots. At JPL, a six-legged robot is currently being developed for
consideration in future missions to such planets as Mars. Such robots include
the LEMUR (Limbed Excursion Mobile Utility Robot). This type of robot would
potentially perform mobility in complex terrains, sample acquisition and
analysis, and many other functions that are attributed to legged animals including
grasping and object manipulation. This evolution may potentially lead to the
use of life-like robots in future NASA missions that involve landing on various
planets including Mars.
The details of such future
missions will be designed as a plot, commonly used in entertainment shows
rather than conventional mission plans of a rover moving in a terrain and
performing simple autonomous tasks. Equipped with multifunctional tools and
multiple cameras, the LEMUR robots are intended to inspect and maintain
installations beyond humanity's easy reach in space with the ability to operate
in harsh planetary environments that are hazardous to human. This spider
looking robot has 6 legs, each of which has interchangeable end-effectors to
perform the required mission (see Figure 4). The axis symmetric layout is a lot
like a starfish or octopus, and it has a panning camera system that allows
omni-directional movement and manipulation operations.
FIGURE
4: A new class of multi-limbed robots called
LEMUR (Limbed Excursion Mobile Utility Robot) is under development at JPL
Robots as part of the
human society:
As robots are getting the appearance and functionalities of humans and
animals there is a growing need to make them interact and communicate as a
sociable partner rather than a tool. This trend is requiring that robots would
be able to communicate, cooperate, and learn from people in familiar
human-oriented terms. Such a capability poses new challenges and motivates new
domestic, entertainment, educational, and health related applications for
robots that play a part in our daily lives. It requires obeying a wide range of
social rules and learned behaviors that guide the interactions with, and
attitudes toward, interactive technologies. Such robots are increasingly
emerging and one example of such a robot is the Kismet that was developed by
Breazeal [2002]. Kismet perceives a variety of natural social cues from visual
and auditory channels, and delivers social signals to people through gaze
direction, facial expression, body posture, and vocalizations.
Natural language processing will
provide important services for people who speak different languages. If a
computer is able to understand natural languages, it will also be able to
translate from one language to another. The "universal translator"
widely used Star Trek may actually become a reality! This, of course, also
includes voice recognition, or speech recognition.
Future of Artificial Intelligence:
In the near future
things such as object recognition, voice recognition, and natural language
understanding will be a reality. Will there be systems so advanced that they
have to be given rights similar to those of humans? Probably not in the
foreseeable future. But maybe in a little more than half a century, if the
humanity survives that long, such machines may very well develop.
Advantage Of Future
Artificial
Intelligence:
They will probably be increasingly used
in the field of medicine. Knowledge based expert system, which can
cross-reference symptoms and diseases will greatly improve the accuracy of
diagnostics. Object recognition will also be a great aid to doctors. Along with
images from cats cans or X-ray machines, they will be able to get preliminary
analysis of those images. This of course will be possible only if people solve
legal questions that arise by giving power to a machine to control or influence
the health of a human.
Idea of Artificial Intelligence
is being replaced by artificial life or anything with a form or body.
- The consensus among scientists is that a requirement
for life is that it has an embodiment in some physical form, but this will
change. Programs may not fit this requirement for life yet.
Applications:
The potential applications of Artificial Intelligence are
abundant. They stretch from the military
for autonomous control and target identification, to the entertainment industry for computer
games and robotic pets. And also big establishments dealing with huge amounts
of information such as hospitals,
banks and insurances, who can use AI to predict
customer behavior and detect trends.
Suggestion And Success:
Use of EAP liquid, called
Electro-Rheological Fluid (ERF), which becomes viscous under electro-activation
we could design miniature Electrically Controlled Stiffness (ECS) elements and
actuators. Using this system, the feeling of the stiffness and forces applied
at remote or virtual environments will be reflected to the users via
proportional changes in ERF viscosity.
The success in developing
EAP actuated robotic arms that can win a wrestling match with human opponent
can greatly
benefit from the development by neurologists.
Using such a capability to control prosthetics which would require feedback to
allow the human operator to “feel” the environment around the artificial limbs.
Such feedback can be provided with the aid of tactile sensors, haptic devices,
and other interfaces. Besides providing feedback, sensors will be needed to
allow the users to monitor the prosthetics from potential damage (heat,
pressure, impact, etc.) just as we are doing with biological limbs. The
development of EAPmaterials that can provide tactile sensing
CONCLUSION:
Using effective EAP
actuators
would immensely expand the collection and
functionality of the actuators that are currently available as well as enable
making artificial organs. The prospect of developing technology that would
enable making “bionic” humans with artificial muscles. These man-made materials
operate as actuators with the closest functional similarity to biological
muscles including resilience, quiet operation, damage tolerance, and large
actuation strains (stretching, contracting or bending).Visco-elastic EAP
materials can provide more lifelike aesthetics, vibration and shock dampening,
and more flexible actuator important addition to this capability can be the
application of telepresence combined with virtual reality using haptic
interfaces. Thus more intelligent biomimetics to improve our lives can be made
in response to the wear inspired by the biology which will increasingly find
challenges to the implementations.
ISRO
