1,962 research outputs found
A versatile and reconfigurable microassembly workstation
In this paper, a versatile and reconfigurable
microassembly workstation designed and realized as a research
tool for investigation of the problems in microassembly and
micromanipulation processes and recent developments on
mechanical and control structure of the system with respect to
the previous workstation are presented. These developments
include: (i) addition of a manipulator system to realize more
complicated assembly and manipulation tasks, (ii) addition of
extra DOF for the vision system and sample holder stages in
order to make the system more versatile (iii) a new optical
microscope as the vision system in order to visualize the
microworld and determine the position and orientation of micro
components to be assembled or manipulated, (iv) a modular
control system hardware which allows handling more DOF. In
addition several experiments using the workstation are presented
in different modes of operation like tele-operated, semiautomated
and fully automated by means of visual based
schemes
Determination of cellular strains by combined atomic force microscopy and finite element modeling
Many organs adapt to their mechanical environment as a result of physiological change or disease. Cells are both the detectors and effectors of this process. Though many studies have been performed in vitro to investigate the mechanisms of detection and adaptation to mechanical strains, the cellular strains remain unknown and results from different stimulation techniques cannot be compared. By combining experimental determination of cell profiles and elasticities by atomic force microscopy with finite element modeling and computational fluid dynamics, we report the cellular strain distributions exerted by common whole-cell straining techniques and from micromanipulation techniques, hence enabling their comparison. Using data from our own analyses and experiments performed by others, we examine the threshold of activation for different signal transduction processes and the strain components that they may detect. We show that modulating cell elasticity, by increasing the F-actin content of the cytoskeleton, or cellular Poisson ratio are good strategies to resist fluid shear or hydrostatic pressure. We report that stray fluid flow in some substrate-stretch systems elicits significant cellular strains. In conclusion, this technique shows promise in furthering our understanding of the interplay among mechanical forces, strain detection, gene expression, and cellular adaptation in physiology and disease
Microfluidics and Bio-MEMS for Next Generation Healthcare.
Ph.D. Thesis. University of Hawaiʻi at Mānoa 2018
Recent advances in the study of Micro/Nano Robotics in France.
International audienceIn France, during the last decade, significant research activities have been performed in the field of micro and nano robotics. Generally speaking the microrobotic field deals with the design, the fabrication and the control of microrobots and microrobotic cells. These microrobots are intended to perform various tasks in the so-called Microworld. The scale effects from macroworld to microworld deeply affect robots in the sense that new hard constraints appear as well as new manufacturing facilities. Concerning the nanorobotics, in order to achieve high-efficiency and three-dimensional nanomanipulation and nanoassembly, parallel imaging/manipulation force microscopy and three-dimensional manipulation force microscope, as well as nanmanipulation in the scanning electron microscope, have been developed. Manipulation of nanocomponents, such as nanoparticles, nanowires and nanotubes, have been addressed to build two-dimensional nano patterns and three-dimensional nano structure
マルチ スケール キノウ ヲ ユウスル コウソク ジドウ マイクロ マニピュレーション システム
Ebubekir Avci, Chanh-Nghiem Nguyen, Kenichi Ohara, Yasushi Mae, Tatsuo Arai, Analysis and suppression of residual vibration in microhand for high-speed single-cell manipulation, International Journal of Mechatronics and Automation, 2013-Vol.3, No.2, pp.110-11
A master relation defines the nonlinear viscoelasticity of single fibroblasts
Cell mechanical functions like locomotion, contraction and division are
controlled by the cytoskeleton, a dynamic biopolymer network whose mechanical
properties remain poorly understood. We perform single-cell uniaxial stretching
experiments on 3T3 fibroblasts. By superimposing small amplitude oscillations
on a mechanically prestressed cell, we find a transition from linear
viscoelastic behavior to power-law stress stiffening. Data from different cells
over several stress decades can be uniquely scaled to obtain a master-relation
between the viscoelastic moduli and the average force. Remarkably, this
relation holds independently of deformation history, adhesion biochemistry, and
intensity of active contraction. In particular, it is irrelevant whether force
is actively generated by the cell or externally imposed by stretching. We
propose that the master-relation reflects the mechanical behavior of the force
bearing actin cytoskeleton, in agreement with stress stiffening known from
semiflexible filament networks.Comment: 12 pages, 11 figures. Accepted for publication in Biophysical
Journal, scheduled to appear in May 200
Autonomous planning and control of soft untethered grippers in unstructured environments
The use of small, maneuverable, untethered and reconfigurable robots could provide numerous advantages in various micromanipulation tasks. Examples include microassembly, pick-and-place of fragile microobjects for lab-on-a-chip applications, assisted hatching for in-vitro fertilization and minimally invasive surgery. This study assesses the potential of soft untethered magnetic grippers as alternatives or complements to conventional tethered or rigid micromanipulators. We demonstrate closed-loop control of untethered grippers and automated pick-and-place of biological material on porcine tissue in an unstructured environment. We also demonstrate the ability of the soft grippers to recognize and sort non-biological micro-scale objects. The fully autonomous nature of the experiments is made possible by the integration of planning and decision-making algorithms, as well as by closed-loop temperature and electromagnetic motion control. The grippers are capable of completing pick-and-place tasks of biological material at an average velocity of 1.8±0.71 mm/s and a drop-off error of 0.62±0.22 mm. Color-sensitive sorting of three micro-scale objects is completed at a velocity of 1.21±0.68 mm/s and a drop-off error of 0.85±0.41 mm. Our findings suggest that improved autonomous un-tethered grippers could augment the capabilities of current soft-robotic instruments especially in advanced tasks involving manipulation
3D 6DOF Manipulation of Micro-object Using Laser Trapped Microtool
Proceedings of the 2006 IEEE International Conference on Robotics and Automation, Orlando, Florida, May 200
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