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2012


Entropy Search for Information-Efficient Global Optimization
Entropy Search for Information-Efficient Global Optimization

Hennig, P., Schuler, C.

Journal of Machine Learning Research, 13, pages: 1809-1837, -, June 2012 (article)

Abstract
Contemporary global optimization algorithms are based on local measures of utility, rather than a probability measure over location and value of the optimum. They thus attempt to collect low function values, not to learn about the optimum. The reason for the absence of probabilistic global optimizers is that the corresponding inference problem is intractable in several ways. This paper develops desiderata for probabilistic optimization algorithms, then presents a concrete algorithm which addresses each of the computational intractabilities with a sequence of approximations and explicitly adresses the decision problem of maximizing information gain from each evaluation.

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PDF Web Project Page [BibTex]

2012


PDF Web Project Page [BibTex]


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From Dynamic Movement Primitives to Associative Skill Memories

Pastor, P., Kalakrishnan, M., Meier, F., Stulp, F., Buchli, J., Theodorou, E., Schaal, S.

Robotics and Autonomous Systems, 2012 (article)

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Project Page [BibTex]

Project Page [BibTex]


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Two-dimensional autonomous microparticle manipulation strategies for magnetic microrobots in fluidic environments

Pawashe, C., Floyd, S., Diller, E., Sitti, M.

IEEE Transactions on Robotics, 28(2):467-477, IEEE, 2012 (article)

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Project Page [BibTex]

Project Page [BibTex]


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Variants of guided self-organization for robot control

Martius, G., Herrmann, J.

Theory in Biosci., 131(3):129-137, Springer Berlin / Heidelberg, 2012 (article)

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link (url) DOI [BibTex]

link (url) DOI [BibTex]


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Three-dimensional microfiber devices that mimic physiological environments to probe cell mechanics and signaling

Ruder, W. C., Pratt, E. D., Bakhru, S., Sitti, M., Zappe, S., Cheng, C., Antaki, J. F., LeDuc, P. R.

Lab on a Chip, 12(10):1775-1779, Royal Society of Chemistry, 2012 (article)

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[BibTex]

[BibTex]


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Active visual search in unknown environments using uncertain semantics

Aydemir, Alper, Pronobis, Andrzej, Jensfelt, Patric, Sj, Kristoffer, Aydemir, Alper, Jensfelt, Patric, Aydemir, A, Jensfelt, P, Aydemir, A, Jensfelt, P, others

Transactions, 1, pages: 2329-2335, IEEE, 2012 (article)

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[BibTex]

[BibTex]


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Modelling of conductive atomic force microscope probes for scanning tunnelling microscope operation

Ozcan, O, Sitti, M

IET Micro \& Nano Letters, 7(4):329-333, IET, 2012 (article)

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[BibTex]

[BibTex]


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Shape memory polymer-based flexure stiffness control in a miniature flapping-wing robot

Hines, L., Arabagi, V., Sitti, M.

IEEE Transactions on Robotics, 28(4):987-990, IEEE, 2012 (article)

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[BibTex]

[BibTex]


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Micro-manipulation using rotational fluid flows induced by remote magnetic micro-manipulators

Ye, Z., Diller, E., Sitti, M.

Journal of Applied Physics, 112(6):064912, AIP, 2012 (article)

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Project Page [BibTex]

Project Page [BibTex]


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Remotely addressable magnetic composite micropumps

Diller, E., Miyashita, S., Sitti, M.

Rsc Advances, 2(9):3850-3856, Royal Society of Chemistry, 2012 (article)

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[BibTex]

[BibTex]


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Model-free reinforcement learning of impedance control in stochastic environments

Stulp, Freek, Buchli, Jonas, Ellmer, Alice, Mistry, Michael, Theodorou, Evangelos A., Schaal, S.

Autonomous Mental Development, IEEE Transactions on, 4(4):330-341, 2012 (article)

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[BibTex]

[BibTex]


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Shape-Programmable Soft Capsule Robots for Semi-Implantable Drug Delivery

Yim, S., Sitti, M.

Mechatronics, IEEE/ASME Transactions on, 2012 (article)

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Project Page [BibTex]

Project Page [BibTex]


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Control of multiple heterogeneous magnetic microrobots in two dimensions on nonspecialized surfaces

Diller, E., Floyd, S., Pawashe, C., Sitti, M.

IEEE Transactions on Robotics, 28(1):172-182, IEEE, 2012 (article)

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[BibTex]

[BibTex]


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Gecko-Inspired Controllable Adhesive Structures Applied to Micromanipulation

Mengüç, Y., Yang, S. Y., Kim, S., Rogers, J. A., Sitti, M.

Advanced Functional Materials, 22(6):1245-1245, WILEY-VCH Verlag, 2012 (article)

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Project Page [BibTex]

Project Page [BibTex]


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Elastomer surfaces with directionally dependent adhesion strength and their use in transfer printing with continuous roll-to-roll applications

Yang, S. Y., Carlson, A., Cheng, H., Yu, Q., Ahmed, N., Wu, J., Kim, S., Sitti, M., Ferreira, P. M., Huang, Y., others,

Advanced Materials, 24(16):2117-2122, WILEY-VCH Verlag, 2012 (article)

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[BibTex]

[BibTex]


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Effect of retraction speed on adhesion of elastomer fibrillar structures

Abusomwan, U., Sitti, M.

Applied Physics Letters, 101(21):211907, AIP, 2012 (article)

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Project Page [BibTex]

Project Page [BibTex]


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Reinforcement Learning with Sequences of Motion Primitives for Robust Manipulation

Stulp, F., Theodorou, E., Schaal, S.

IEEE Transactions on Robotics, 2012 (article)

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[BibTex]

[BibTex]


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Impact and Surface Tension in Water: a Study of Landing Bodies

Shih, B., Laham, L., Lee, K. J., Krasnoff, N., Diller, E., Sitti, M.

Bio-inspired Robotics Final Project, Carnegie Mellon University, 2012 (article)

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[BibTex]

[BibTex]


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Design and rolling locomotion of a magnetically actuated soft capsule endoscope

Yim, S., Sitti, M.

IEEE Transactions on Robotics, 28(1):183-194, IEEE, 2012 (article)

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Project Page [BibTex]

Project Page [BibTex]


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Design and manufacturing of a controllable miniature flapping wing robotic platform

Arabagi, V., Hines, L., Sitti, M.

The International Journal of Robotics Research, 31(6):785-800, SAGE Publications Sage UK: London, England, 2012 (article)

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[BibTex]

[BibTex]


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Chemotactic steering of bacteria propelled microbeads

Kim, D., Liu, A., Diller, E., Sitti, M.

Biomedical microdevices, 14(6):1009-1017, Springer US, 2012 (article)

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Project Page [BibTex]

Project Page [BibTex]

2008


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Learning to control in operational space

Peters, J., Schaal, S.

International Journal of Robotics Research, 27, pages: 197-212, 2008, clmc (article)

Abstract
One of the most general frameworks for phrasing control problems for complex, redundant robots is operational space control. However, while this framework is of essential importance for robotics and well-understood from an analytical point of view, it can be prohibitively hard to achieve accurate control in face of modeling errors, which are inevitable in com- plex robots, e.g., humanoid robots. In this paper, we suggest a learning approach for opertional space control as a direct inverse model learning problem. A first important insight for this paper is that a physically cor- rect solution to the inverse problem with redundant degrees-of-freedom does exist when learning of the inverse map is performed in a suitable piecewise linear way. The second crucial component for our work is based on the insight that many operational space controllers can be understood in terms of a constrained optimal control problem. The cost function as- sociated with this optimal control problem allows us to formulate a learn- ing algorithm that automatically synthesizes a globally consistent desired resolution of redundancy while learning the operational space controller. From the machine learning point of view, this learning problem corre- sponds to a reinforcement learning problem that maximizes an immediate reward. We employ an expectation-maximization policy search algorithm in order to solve this problem. Evaluations on a three degrees of freedom robot arm are used to illustrate the suggested approach. The applica- tion to a physically realistic simulator of the anthropomorphic SARCOS Master arm demonstrates feasibility for complex high degree-of-freedom robots. We also show that the proposed method works in the setting of learning resolved motion rate control on real, physical Mitsubishi PA-10 medical robotics arm.

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link (url) DOI [BibTex]

2008


link (url) DOI [BibTex]


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ENHANCED ADHESION OF PDMS SURFACES FUNCTIONALIZED BY POLY (n-BUTYL ACRYLATE) BRUSHES INSPIRED BY GECKO FOOT HAIRS

Nese, A., Lee, H., Dong, H., Aksak, B., Cusick, B., Kowalewski, T., Matyjaszewski, K., Sitti, M.

Polymer Preprints, 49(2):107, 2008 (article)

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[BibTex]

[BibTex]


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Design and development of the lifting and propulsion mechanism for a biologically inspired water runner robot

Floyd, S., Sitti, M.

IEEE transactions on robotics, 24(3):698-709, IEEE, 2008 (article)

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[BibTex]

[BibTex]


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Control of Cell Behavior by Aligned Micro/Nanofibrous Biomaterial Scaffolds Fabricated by Spinneret-Based Tunable Engineered Parameters (STEP) Technique

Nain, A. S., Phillippi, J. A., Sitti, M., MacKrell, J., Campbell, P. G., Amon, C.

Small, 4(8):1153-1159, Wiley Online Library, 2008 (article)

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[BibTex]

[BibTex]


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Adaptation to a sub-optimal desired trajectory

M. Mistry, E. A. G. L. T. Y. S. S. M. K.

Advances in Computational Motor Control VII, Symposium at the Society for Neuroscience Meeting, Washington DC, 2008, 2008, clmc (article)

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PDF [BibTex]

PDF [BibTex]


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Rolling and spinning friction characterization of fine particles using lateral force microscopy based contact pushing

Sümer, B., Sitti, M.

Journal of Adhesion Science and Technology, 22(5-6):481-506, Taylor & Francis Group, 2008 (article)

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[BibTex]

[BibTex]


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Modeling the soft backing layer thickness effect on adhesion of elastic microfiber arrays

Long, R., Hui, C., Kim, S., Sitti, M.

Journal of Applied Physics, 104(4):044301, AIP, 2008 (article)

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Project Page [BibTex]

Project Page [BibTex]


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Cross-talk compensation in atomic force microscopy

Onal, C. D., Sümer, B., Sitti, M.

Review of scientific instruments, 79(10):103706, AIP, 2008 (article)

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[BibTex]

[BibTex]


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Operational space control: A theoretical and emprical comparison

Nakanishi, J., Cory, R., Mistry, M., Peters, J., Schaal, S.

International Journal of Robotics Research, 27(6):737-757, 2008, clmc (article)

Abstract
Dexterous manipulation with a highly redundant movement system is one of the hallmarks of hu- man motor skills. From numerous behavioral studies, there is strong evidence that humans employ compliant task space control, i.e., they focus control only on task variables while keeping redundant degrees-of-freedom as compliant as possible. This strategy is robust towards unknown disturbances and simultaneously safe for the operator and the environment. The theory of operational space con- trol in robotics aims to achieve similar performance properties. However, despite various compelling theoretical lines of research, advanced operational space control is hardly found in actual robotics imple- mentations, in particular new kinds of robots like humanoids and service robots, which would strongly profit from compliant dexterous manipulation. To analyze the pros and cons of different approaches to operational space control, this paper focuses on a theoretical and empirical evaluation of different methods that have been suggested in the literature, but also some new variants of operational space controllers. We address formulations at the velocity, acceleration and force levels. First, we formulate all controllers in a common notational framework, including quaternion-based orientation control, and discuss some of their theoretical properties. Second, we present experimental comparisons of these approaches on a seven-degree-of-freedom anthropomorphic robot arm with several benchmark tasks. As an aside, we also introduce a novel parameter estimation algorithm for rigid body dynamics, which ensures physical consistency, as this issue was crucial for our successful robot implementations. Our extensive empirical results demonstrate that one of the simplified acceleration-based approaches can be advantageous in terms of task performance, ease of parameter tuning, and general robustness and compliance in face of inevitable modeling errors.

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link (url) [BibTex]

link (url) [BibTex]


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Adhesion of biologically inspired oil-coated polymer micropillars

Cheung, E., Sitti, M.

Journal of Adhesion Science and Technology, 22(5-6):569-589, Taylor & Francis Group, 2008 (article)

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[BibTex]

[BibTex]


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Vision-based feedback strategy for controlled pushing of microparticles

Lynch, N. A., Onal, C. D., Schuster, E., Sitti, M.

Journal of Micro-Nano Mechatronics, 4(1-2):73-83, Springer-Verlag, 2008 (article)

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[BibTex]

[BibTex]


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Effect of quantity and configuration of attached bacteria on bacterial propulsion of microbeads

Behkam, B., Sitti, M.

Applied Physics Letters, 93(22):223901, AIP, 2008 (article)

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[BibTex]

[BibTex]


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A library for locally weighted projection regression

Klanke, S., Vijayakumar, S., Schaal, S.

Journal of Machine Learning Research, 9, pages: 623-626, 2008, clmc (article)

Abstract
In this paper we introduce an improved implementation of locally weighted projection regression (LWPR), a supervised learning algorithm that is capable of handling high-dimensional input data. As the key features, our code supports multi-threading, is available for multiple platforms, and provides wrappers for several programming languages.

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link (url) [BibTex]

link (url) [BibTex]


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Preface to the Journal of Micro-Nano Mechatronics

Dario, P., Fukuda, T., Sitti, M.

Journal of Micro-Nano Mechatronics, 4(1-2):1-1, Springer-Verlag, 2008 (article)

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[BibTex]

[BibTex]


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A legged anchoring mechanism for capsule endoscopes using micropatterned adhesives

Glass, P., Cheung, E., Sitti, M.

IEEE Transactions on Biomedical Engineering, 55(12):2759-2767, IEEE, 2008 (article)

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Project Page [BibTex]

Project Page [BibTex]


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Optimization strategies in human reinforcement learning

Hoffmann, H., Theodorou, E., Schaal, S.

Advances in Computational Motor Control VII, Symposium at the Society for Neuroscience Meeting, Washington DC, 2008, 2008, clmc (article)

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PDF [BibTex]

PDF [BibTex]


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Dynamic modeling of stick slip motion in an untethered magnetic microrobot

Pawashe, C., Floyd, S., Sitti, M.

Proceedings of Robotics: Science and Systems IV, Zurich, Switzerland, 2008 (article)

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[BibTex]

[BibTex]

2007


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Bacterial flagella-based propulsion and on/off motion control of microscale objects

Behkam, B., Sitti, M.

Applied Physics Letters, 90(2):023902, AIP, 2007 (article)

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[BibTex]

2007


[BibTex]


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Friction of partially embedded vertically aligned carbon nanofibers inside elastomers

Aksak, B., Sitti, M., Cassell, A., Li, J., Meyyappan, M., Callen, P.

Applied Physics Letters, 91(6):061906, AIP, 2007 (article)

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[BibTex]

[BibTex]


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Enhanced friction of elastomer microfiber adhesives with spatulate tips

Kim, S., Aksak, B., Sitti, M.

Applied Physics Letters, 91(22):221913, AIP, 2007 (article)

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Project Page [BibTex]

Project Page [BibTex]


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The new robotics - towards human-centered machines

Schaal, S.

HFSP Journal Frontiers of Interdisciplinary Research in the Life Sciences, 1(2):115-126, 2007, clmc (article)

Abstract
Research in robotics has moved away from its primary focus on industrial applications. The New Robotics is a vision that has been developed in past years by our own university and many other national and international research instiutions and addresses how increasingly more human-like robots can live among us and take over tasks where our current society has shortcomings. Elder care, physical therapy, child education, search and rescue, and general assistance in daily life situations are some of the examples that will benefit from the New Robotics in the near future. With these goals in mind, research for the New Robotics has to embrace a broad interdisciplinary approach, ranging from traditional mathematical issues of robotics to novel issues in psychology, neuroscience, and ethics. This paper outlines some of the important research problems that will need to be resolved to make the New Robotics a reality.

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link (url) [BibTex]

link (url) [BibTex]


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Microscale and nanoscale robotics systems [grand challenges of robotics]

Sitti, M.

IEEE Robotics \& Automation Magazine, 14(1):53-60, IEEE, 2007 (article)

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[BibTex]

[BibTex]


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A new biomimetic adhesive for therapeutic capsule endoscope applications in the gastrointestinal tract

Glass, P., Sitti, M., Appasamy, R.

Gastrointestinal Endoscopy, 65(5):AB91, Mosby, 2007 (article)

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[BibTex]

[BibTex]


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Visual servoing-based autonomous 2-D manipulation of microparticles using a nanoprobe

Onal, C. D., Sitti, M.

IEEE Transactions on control systems technology, 15(5):842-852, IEEE, 2007 (article)

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[BibTex]

[BibTex]


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Adhesion of biologically inspired vertical and angled polymer microfiber arrays

Aksak, B., Murphy, M. P., Sitti, M.

Langmuir, 23(6):3322-3332, ACS Publications, 2007 (article)

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Project Page [BibTex]

Project Page [BibTex]


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Waalbot: An agile small-scale wall-climbing robot utilizing dry elastomer adhesives

Murphy, M. P., Sitti, M.

IEEE/ASME transactions on Mechatronics, 12(3):330-338, IEEE, 2007 (article)

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[BibTex]

[BibTex]


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Subfeature patterning of organic and inorganic materials using robotic assembly

Tafazzoli, A., Cheng, C., Pawashe, C., Sabo, E. K., Trofin, L., Sitti, M., LeDuc, P. R.

Journal of materials research, 22(06):1601-1608, Cambridge University Press, 2007 (article)

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[BibTex]

[BibTex]