666 research outputs found
Recommended from our members
Stable reflex-based walking of forelimbs of a bio-inspired quadruped robot-modeled cheetah
In contrast to the high movement adaptability of
quadruped animals in many environmental conditions, it is
hard for conventional quadruped robots to operate in complex
environment conditions. We investigate the adaptability of
animalsâ musculo-skeletal systems, by building a bio-inspired
quadruped robot named âPneupardâ which duplicates a feline
musculo-skeletal system. In this study, we built Pneupardâs
forelimb which has 14 active muscles, 4 passive muscles and 8
degrees of freedom (DOF). We propose sole reflex-based control
and verify its effectiveness by conducting walking experiments,
in which the robot performed stable walking with a two-dimensional
restriction.This work was partially supported by a Grant-in-Aid for Scientific
Research(23220004) from the Japanese Ministry of Education, Culture,
Sports, Science and Technology.This is the accepted manuscript. The final version is available at http://dx.doi.org/10.1109/ROBIO.2013.673973
Recommended from our members
Pneupard: A biomimetic musculoskeletal approach for a feline-inspired quadruped robot
Feline locomotion combines great acrobatic proficiency,
unparalleled balance and higher accelerations than
other animals. Capable of accelerating from 0 to 100 km hâ1 in
three seconds, the cheetah (Acinonyx jubatus) is still a mystery
which intrigues scientists. Aiming for a better understanding
of the source of such higher speeds, we develop a biomimetic
platform, where musculoskeletal parameters (range of motion
and moment arms) from the biological system can be evaluated
with air muscles within a lightweight robotic structure. We performed
experiments validating the muscular structure during
a treadmill walk, successfully reproducing animal locomotion
while adopting an EMG based control method.This work was partially supported by KAKENHI Kiban(S) 23220004.This is the accepted manuscript. The final version is available at http://dx.doi.org/10.1109/IROS.2013.6696540
Producing alternating gait on uncoupled feline hindlimbs: Muscular unloading rule on a biomimetic robot
Studies on decerebrate walking cats have shown that phase transition is strongly related to muscular sensory signals at limbs. To further investigate the role of such signals terminating the stance phase, we developed a biomimetic feline platform. Adopting link lengths and moment arms from an Acinonyx jubatus, we built a pair of hindlimbs connected to a hindquarter and attached it to a sliding strut, simulating solid forelimbs. Artificial pneumatic muscles simulate biological muscles through a control method based on EMG signals from walking cats (Felis catus). Using the bio-inspired muscular unloading rule, where a decreasing ground reaction force triggers phase transition, stable walking on a treadmill was achieved. Finally, an alternating gait is possible using the unloading rule, withstanding disturbances and systematic muscular changes, not only contributing to our understanding on how cats may walk, but also helping develop better legged robots.The authors acknouledge the Japanese Research Grant KAKENHI Kiban 23220004 and 25540117.This is the author accepted manuscript. The final version is available from Taylor & Francis via http://dx.doi.org/10.1080/01691864.2013.87049
Recommended from our members
Exploring muscular contribution during stepping of biomimetic feline hindlimbs
Although robotic locomotion have greatly advanced
over the past years, the abyss that separates such locomotion
from even the simplest animal locomotions prompt us to
approach robotic locomotion taking cues from animals. The animal
musculoskeletal structure, often ignored by roboticists due
to its high redundancy and complexity, might hold the secret
for self-stable locomotion observed in bipeds and quadrupeds.
Aiming to better understand how muscles contribute to selfstable
locomotion we take the feline structure as a model on
a biomimetic approach. Using 6 air muscles per hindlimb to
mimic real muscles, this robot walks stably on a treadmill while
supported by a slider, simulating forelimbs. We individually
evaluate muscle contribution to walking stability, performing a
comparison between mono and biarticular synergistic muscles
at the ankle and concluding that a higher compliance on
the biarticular muscle improved walking stability. A better
understanding of such complex phenomena may help on the
development of better legged robots in the future, truly taking
advantage of concepts developed by nature over the years.This work was partially supported by KAKENHI Kiban(S) 23220004.This is the accepted manuscript. The final version is available at http://ieeexplore.ieee.org/xpls/abs_all.jsp?arnumber=6739573&tag=1
N=2 Supersymmetric Sigma Models and D-branes
We study D-branes of N=2 supersymmetric sigma models. Supersymmetric
nonlinear sigma models with 2-dimensional target space have D0,D1,D2-branes,
which are realized as A-,B-type supersymmetric boundary conditions on the
worldsheet. When we embed the models in the string theory, the Kahler potential
is restricted and leads to a 2-dim black hole metric with a dilaton background.
The D-branes in this model are susy cycles and consistent with the analysis of
conjugacy classes. The generalized metrics with U(n) isometry is proposed and
dynamics on them are realized by linear sigma models. We investigate D-branes
of the linear sigma models and compare the results with those in the nonlinear
sigma models.Comment: 23 pages, 5 figure
Realization of three-dimensional walking of a cheetah-modeled bio-inspired quadruped robot
Adaptability of quadruped animals is not solely
reached by brain control, but by the interaction between its
body, environment, and control. Especially, morphology of the
body is supposed to contribute largely to the adaptability. We
have tried to understand quadrupedal locomotion by building
a bio-inspired quadruped robot named âPneupardâ, which has
a feline-like muscular-skeletal structure. In our previous study,
we successfully realized alternative gait of hindlimbs by reflex
control based on the sole touch information, which is called an
unloading rule, and that of forelimbs as well. In this paper, we
finally connect forelimbs and hindlimbs by a rigid spine, and
conduct 3D walking experiments only with the simple unloading
rule. Through several preliminary experiments, we realize that
the touch information on the sole is the most critical for stable
3D walking.This work was partially supported by Grant-in-Aid for Scientific Research
on 23220004, 25540117 of Japan.This is the accepted manuscript. The final version is available at http://dx.doi.org/10.1109/ROBIO.2014.7090426
Bacterial Biofilms and Their Implications in Pathogenesis and Food Safety
Biofilm formation is an integral part of the microbial life cycle in nature. In food processing environments, bacterial transmissions occur primarily through raw or undercooked foods and by cross-contamination during unsanitary food preparation practices. Foodborne pathogens form biofilms as a survival strategy in various unfavorable environments, which also become a frequent source of recurrent contamination and outbreaks of foodborne illness. Instead of focusing on bacterial biofilm formation and their pathogenicity individually, this review discusses on a molecular level how these two physiological processes are connected in several common foodborne pathogens such as Listeria monocytogenes, Staphylococcus aureus, Salmonella enterica and Escherichia coli. In addition, biofilm formation by Pseudomonas aeruginosa is discussed because it aids the persistence of many foodborne pathogens forming polymicrobial biofilms on food contact surfaces, thus significantly elevating food safety and public health concerns. Furthermore, in-depth analyses of several bacterial molecules with dual functions in biofilm formation and pathogenicity are highlighted
- âŠ