Adhesion and Anisotropic Friction Enhancements of Angled Heterogeneous Micro-Fiber Arrays with Spherical and Spatula Tips

@article{karagozler-TCCS12,
  author = {Karagozler, Mustafa Emre and Goldstein, Seth Copen and
     Ricketts, David S.},
  journal = {Circuits and Systems I: Regular Papers, IEEE Transactions
     on},
  title = {Analysis and Modeling of Capacitive Power Transfer in
     Microsystems},
  year = {2012},
  month = {July},
  volume = {59},
  number = {7},
  pages = {1557 -1566},
  keywords = {Actuation, Adhesion,Power},
  doi = {10.1109/TCSI.2011.2177011},
  issn = {1549-8328},
}

@inproceedings{bkirby-iros07,
  author = {Kirby, Brian and Aksak, Burak and Goldstein, Seth Copen
     and Hoburg, James F. and Mowry, Todd C. and Pillai, Padmanabhan},
  title = {A Modular Robotic System Using Magnetic Force Effectors},
  booktitle = {Proceedings of the IEEE International Conference on
     Intelligent Robots and Systems ({IROS '07})},
  venue = {IEEE/RSJ International Conference on Intelligent Robots and
     Systems (IROS)},
  year = {2007},
  month = {October},
  abstract = {One of the primary impediments to building ensembles
     with many modular robots is the complexity and number of
     mechanical mechanisms used to construct the individual modules.
     As part of the Claytronics project---which aims to build very
     large ensembles of modular robots---we investigate how to
     simplify each module by eliminating moving parts and reducing the
     number of mechanical mechanisms on each robot by using
     force-at-a-distance actuators. Additionally, we are also
     investigating the feasibility of using these unary actuators to
     improve docking performance, implement intermodule adhesion,
     power transfer, communication, and sensing.},
  keywords = {Actuation, Adhesion},
  url = {http://www.cs.cmu.edu/~claytronics/papers/bkirby-iros07.pdf},
}

@inproceedings{aksak-pass07,
  author = {Murphy, M.P. and Aksak, Burak and Sitti, Metin},
  title = {Adhesion Behavior of Vertical and Aligned Polymer
     Microfibers},
  booktitle = {Proceedings of Adhesion Society Symposium},
  venue = {Proceedings of Adhesion Society Symposium},
  year = {2007},
  month = {February},
  keywords = {Adhesion, Dry Adhesive},
  url = {http://www.cs.cmu.edu/~claytronics/papers/aksak-pass07.pdf},
}

@article{aksak-jast07,
  author = {Murphy, M.P. and Aksak, Burak and Sitti, Metin},
  title = {Adhesion and Anisotropic Friction Enhancements of Angled
     Heterogeneous Micro-Fiber Arrays with Spherical and Spatula
     Tips},
  journal = {Journal of Adhesion Science and Technology},
  venue = {Journal of Adhesion Science and Technology},
  year = {2007},
  institution = {NanoRobotics Laboratory, Department of Mechanical
     Engineering, Carnegie Mellon University, Pittsburgh, Pennsylvania
     15213},
  abstract = {Angled polyurethane fiber arrays are modified by adding
     soft spherical and spatula shaped tips by dipping. These fibers
     are characterized for adhesion and friction and compared with
     unmodified fibers and flat material samples. Sphere and spatula
     tip fiber samples demonstrate increased adhesion, with 10 and 23
     times the maximum adhesion of the unmodified fiber sample,
     respectively. The sphere and spatula tip fiber samples also show
     increased friction, with 1.6 and 4.7 times the maximum friction
     of the unmodified fiber sample, respectively. Simultaneous
     friction and adhesion is observed in a synthetic dry angled
     fibrillar adhesive sample (spatula tip fiber sample) for the
     first time. The direction dependent friction of angled fibers is
     investigated and observed. The adhesion and friction results
     reported in this paper suggest that fibers with negligible
     adhesion can be modified to exhibit significant adhesion and
     friction enhancement by the proposed fiber tip modifications.},
  keywords = {Gecko, Adhesion, Angled Fiber Array, Friction, Dry
     Adhesive, Bioinspired adhesive},
  url = {http://www.cs.cmu.edu/~claytronics/papers/aksak-jast07.pdf},
}

@article{aksak-langmuir2007,
  author = {Aksak, Burak and Murphy, M.P. and Sitti, Metin},
  title = {Adhesion of Biologically Inspired Vertical and Angled
     Polymer Microfiber Arrays},
  journal = {Langmuir},
  venue = {Langmuir},
  year = {2007},
  month = {February},
  volume = {23},
  pages = {3322--32},
  number = {6},
  institution = {NanoRobotics Laboratory, Department of Mechanical
     Engineering, Carnegie Mellon University, Pittsburgh, Pennsylvania
     15213},
  issn = {0743-7463},
  keywords = {Adhesion, Biologically Inspired},
  abstract = {This paper proposes an approximate adhesion model for
     fibrillar adhesives for developing a fibrillar adhesive design
     methodology and compares numerical simulation adhesion results
     with macroscale adhesion data from polymer microfiber array
     experiments. A technique for fabricating microfibers with a
     controlled angle is described for the first time. Polyurethane
     microfibers with different hardnesses, angles, and aspect ratios
     are fabricated using optical lithography and polymer micromolding
     techniques and tested with a custom tensile adhesion measurement
     setup. Macroscale adhesion and overall work of adhesion of the
     microfiber arrays are measured and compared with the models to
     observe the effect of fiber geometry and preload. The adhesion
     strength and work of adhesion behavior of short and long vertical
     and long angled fiber arrays have similar trends with the
     numerical simulations. A scheme is also proposed to aid in
     optimized fiber adhesive design.},
  url = {http://www.cs.cmu.edu/~claytronics/papers/aksak-langmuir2007.pdf},
}

@inproceedings{karagozler-iros07,
  author = {Karagozler, Mustafa Emre and Campbell, Jason D. and
     Fedder, Gary K. and Goldstein, Seth Copen and Weller, Michael
     Philetus and Yoon, Byung W.},
  title = {Electrostatic Latching for Inter-module Adhesion, Power
     Transfer, and Communication in Modular Robots},
  booktitle = {Proceedings of the IEEE International Conference on
     Intelligent Robots and Systems ({IROS '07})},
  venue = {IEEE/RSJ International Conference on Intelligent Robots and
     Systems (IROS)},
  see = {karagozler-msreport07},
  year = {2007},
  month = {October},
  abstract = {A simple and robust inter-module latch is possibly the
     most important component of a modular robotic system. This paper
     describes a latch based on capacitive coupling which not only
     provides significant adhesion forces, but can also be used for
     inter-module power transmission and communication. The key
     insight that enables electrostatic adhesion to be effective at
     the macroscale is to combine flexible electrodes with a geometery
     that uses shear forces to provide adhesion. To measure the
     effectiveness of our latch we incorporated it into a 28cm x 28cm
     x 28cm modular robot. The result is a latch which requires almost
     zero static power and yet can hold over 0.6N/cm^2 of latch
     area.},
  keywords = {Actuation, Adhesion},
  url = {http://www.cs.cmu.edu/~claytronics/papers/karagozler-iros07.pdf},
}

@mastersthesis{karagozler-msreport07,
  author = {Karagozler, Mustafa Emre},
  title = {Harnessing Capacitance for Inter-Robot Latching,
     Communication, and Power Transfer},
  venue = {Masters Thesis},
  also = {Electrostatic Latching for Inter-module Adhesion, Power
     Transfer, and Communication in Modular Robots in IROS '07},
  month = {May},
  year = {2007},
  school = {Carnegie Mellon University},
  abstract = {A simple and robust inter-module latch is possibly the
     most important component of a modular robotic system. This report
     describes a latch based on capacitive coupling which not only
     provides significant adhesion forces, but can also be used for
     inter-module power transmission and communication. The key
     insight that enables electrostatic adhesion to be effective at
     the macro scale is to combine flexible electrodes with a geometry
     that uses shear forces to provide adhesion. To measure the
     effectiveness of our latch we incorporated it into a 28cm x 28cm
     x 28cm modular robot. The result is a latch which requires almost
     zero static power and yet can hold over 0.6N/cm2 of latch area.},
  keywords = {Actuation, Adhesion, Power},
  url = {http://www.cs.cmu.edu/~claytronics/papers/karagozler-msreport07.pdf},
}

@inproceedings{weller-iros07,
  author = {Weller, Michael Philetus and Karagozler, Mustafa Emre and
     Kirby, Brian and Campbell, Jason D. and Goldstein, Seth Copen},
  title = {Movement Primitives for an Orthogonal Prismatic
     Closed-Lattice-Constrained Self-Reconfiguring Module},
  booktitle = {Workshop on Self-Reconfiguring Modular Robotics at the
     IEEE International Conference on Intelligent Robots and Systems
     (IROS) '07},
  venue = {Workshop on Self-Reconfigurable Robots/Systems and
     Applications at IROS},
  year = {2007},
  month = {October},
  keywords = {Adhesion, Robotics, Planning},
  abstract = {We describe a new set of prismatic movement primitives
     for cubic modular robots. Our approach appears more practical
     than previous metamodule-based approaches. We also describe
     recent hardware developments in our cubic robot modules that have
     sufficient stiffness and actuator strength so that when they work
     together they can realize, in earth's gravity, all of the motion
     primitives we describe here.},
  url = {http://www.cs.cmu.edu/~claytronics/papers/weller-iros07.pdf},
}

@inproceedings{aksak-pass07,
  author = {Murphy, M.P. and Aksak, Burak and Sitti, Metin},
  title = {Adhesion Behavior of Vertical and Aligned Polymer
     Microfibers},
  booktitle = {Proceedings of Adhesion Society Symposium},
  venue = {Proceedings of Adhesion Society Symposium},
  year = {2007},
  month = {February},
  keywords = {Adhesion, Dry Adhesive},
  url = {http://www.cs.cmu.edu/~claytronics/papers/aksak-pass07.pdf},
}

@article{aksak-jast07,
  author = {Murphy, M.P. and Aksak, Burak and Sitti, Metin},
  title = {Adhesion and Anisotropic Friction Enhancements of Angled
     Heterogeneous Micro-Fiber Arrays with Spherical and Spatula
     Tips},
  journal = {Journal of Adhesion Science and Technology},
  venue = {Journal of Adhesion Science and Technology},
  year = {2007},
  institution = {NanoRobotics Laboratory, Department of Mechanical
     Engineering, Carnegie Mellon University, Pittsburgh, Pennsylvania
     15213},
  abstract = {Angled polyurethane fiber arrays are modified by adding
     soft spherical and spatula shaped tips by dipping. These fibers
     are characterized for adhesion and friction and compared with
     unmodified fibers and flat material samples. Sphere and spatula
     tip fiber samples demonstrate increased adhesion, with 10 and 23
     times the maximum adhesion of the unmodified fiber sample,
     respectively. The sphere and spatula tip fiber samples also show
     increased friction, with 1.6 and 4.7 times the maximum friction
     of the unmodified fiber sample, respectively. Simultaneous
     friction and adhesion is observed in a synthetic dry angled
     fibrillar adhesive sample (spatula tip fiber sample) for the
     first time. The direction dependent friction of angled fibers is
     investigated and observed. The adhesion and friction results
     reported in this paper suggest that fibers with negligible
     adhesion can be modified to exhibit significant adhesion and
     friction enhancement by the proposed fiber tip modifications.},
  keywords = {Gecko, Adhesion, Angled Fiber Array, Friction, Dry
     Adhesive, Bioinspired adhesive},
  url = {http://www.cs.cmu.edu/~claytronics/papers/aksak-jast07.pdf},
}

@article{aksak-jast07,
  author = {Murphy, M.P. and Aksak, Burak and Sitti, Metin},
  title = {Adhesion and Anisotropic Friction Enhancements of Angled
     Heterogeneous Micro-Fiber Arrays with Spherical and Spatula
     Tips},
  journal = {Journal of Adhesion Science and Technology},
  venue = {Journal of Adhesion Science and Technology},
  year = {2007},
  institution = {NanoRobotics Laboratory, Department of Mechanical
     Engineering, Carnegie Mellon University, Pittsburgh, Pennsylvania
     15213},
  abstract = {Angled polyurethane fiber arrays are modified by adding
     soft spherical and spatula shaped tips by dipping. These fibers
     are characterized for adhesion and friction and compared with
     unmodified fibers and flat material samples. Sphere and spatula
     tip fiber samples demonstrate increased adhesion, with 10 and 23
     times the maximum adhesion of the unmodified fiber sample,
     respectively. The sphere and spatula tip fiber samples also show
     increased friction, with 1.6 and 4.7 times the maximum friction
     of the unmodified fiber sample, respectively. Simultaneous
     friction and adhesion is observed in a synthetic dry angled
     fibrillar adhesive sample (spatula tip fiber sample) for the
     first time. The direction dependent friction of angled fibers is
     investigated and observed. The adhesion and friction results
     reported in this paper suggest that fibers with negligible
     adhesion can be modified to exhibit significant adhesion and
     friction enhancement by the proposed fiber tip modifications.},
  keywords = {Gecko, Adhesion, Angled Fiber Array, Friction, Dry
     Adhesive, Bioinspired adhesive},
  url = {http://www.cs.cmu.edu/~claytronics/papers/aksak-jast07.pdf},
}

@article{aksak-jast07,
  author = {Murphy, M.P. and Aksak, Burak and Sitti, Metin},
  title = {Adhesion and Anisotropic Friction Enhancements of Angled
     Heterogeneous Micro-Fiber Arrays with Spherical and Spatula
     Tips},
  journal = {Journal of Adhesion Science and Technology},
  venue = {Journal of Adhesion Science and Technology},
  year = {2007},
  institution = {NanoRobotics Laboratory, Department of Mechanical
     Engineering, Carnegie Mellon University, Pittsburgh, Pennsylvania
     15213},
  abstract = {Angled polyurethane fiber arrays are modified by adding
     soft spherical and spatula shaped tips by dipping. These fibers
     are characterized for adhesion and friction and compared with
     unmodified fibers and flat material samples. Sphere and spatula
     tip fiber samples demonstrate increased adhesion, with 10 and 23
     times the maximum adhesion of the unmodified fiber sample,
     respectively. The sphere and spatula tip fiber samples also show
     increased friction, with 1.6 and 4.7 times the maximum friction
     of the unmodified fiber sample, respectively. Simultaneous
     friction and adhesion is observed in a synthetic dry angled
     fibrillar adhesive sample (spatula tip fiber sample) for the
     first time. The direction dependent friction of angled fibers is
     investigated and observed. The adhesion and friction results
     reported in this paper suggest that fibers with negligible
     adhesion can be modified to exhibit significant adhesion and
     friction enhancement by the proposed fiber tip modifications.},
  keywords = {Gecko, Adhesion, Angled Fiber Array, Friction, Dry
     Adhesive, Bioinspired adhesive},
  url = {http://www.cs.cmu.edu/~claytronics/papers/aksak-jast07.pdf},
}

@article{aksak-jast07,
  author = {Murphy, M.P. and Aksak, Burak and Sitti, Metin},
  title = {Adhesion and Anisotropic Friction Enhancements of Angled
     Heterogeneous Micro-Fiber Arrays with Spherical and Spatula
     Tips},
  journal = {Journal of Adhesion Science and Technology},
  venue = {Journal of Adhesion Science and Technology},
  year = {2007},
  institution = {NanoRobotics Laboratory, Department of Mechanical
     Engineering, Carnegie Mellon University, Pittsburgh, Pennsylvania
     15213},
  abstract = {Angled polyurethane fiber arrays are modified by adding
     soft spherical and spatula shaped tips by dipping. These fibers
     are characterized for adhesion and friction and compared with
     unmodified fibers and flat material samples. Sphere and spatula
     tip fiber samples demonstrate increased adhesion, with 10 and 23
     times the maximum adhesion of the unmodified fiber sample,
     respectively. The sphere and spatula tip fiber samples also show
     increased friction, with 1.6 and 4.7 times the maximum friction
     of the unmodified fiber sample, respectively. Simultaneous
     friction and adhesion is observed in a synthetic dry angled
     fibrillar adhesive sample (spatula tip fiber sample) for the
     first time. The direction dependent friction of angled fibers is
     investigated and observed. The adhesion and friction results
     reported in this paper suggest that fibers with negligible
     adhesion can be modified to exhibit significant adhesion and
     friction enhancement by the proposed fiber tip modifications.},
  keywords = {Gecko, Adhesion, Angled Fiber Array, Friction, Dry
     Adhesive, Bioinspired adhesive},
  url = {http://www.cs.cmu.edu/~claytronics/papers/aksak-jast07.pdf},
}

@article{aksak-jast07,
  author = {Murphy, M.P. and Aksak, Burak and Sitti, Metin},
  title = {Adhesion and Anisotropic Friction Enhancements of Angled
     Heterogeneous Micro-Fiber Arrays with Spherical and Spatula
     Tips},
  journal = {Journal of Adhesion Science and Technology},
  venue = {Journal of Adhesion Science and Technology},
  year = {2007},
  institution = {NanoRobotics Laboratory, Department of Mechanical
     Engineering, Carnegie Mellon University, Pittsburgh, Pennsylvania
     15213},
  abstract = {Angled polyurethane fiber arrays are modified by adding
     soft spherical and spatula shaped tips by dipping. These fibers
     are characterized for adhesion and friction and compared with
     unmodified fibers and flat material samples. Sphere and spatula
     tip fiber samples demonstrate increased adhesion, with 10 and 23
     times the maximum adhesion of the unmodified fiber sample,
     respectively. The sphere and spatula tip fiber samples also show
     increased friction, with 1.6 and 4.7 times the maximum friction
     of the unmodified fiber sample, respectively. Simultaneous
     friction and adhesion is observed in a synthetic dry angled
     fibrillar adhesive sample (spatula tip fiber sample) for the
     first time. The direction dependent friction of angled fibers is
     investigated and observed. The adhesion and friction results
     reported in this paper suggest that fibers with negligible
     adhesion can be modified to exhibit significant adhesion and
     friction enhancement by the proposed fiber tip modifications.},
  keywords = {Gecko, Adhesion, Angled Fiber Array, Friction, Dry
     Adhesive, Bioinspired adhesive},
  url = {http://www.cs.cmu.edu/~claytronics/papers/aksak-jast07.pdf},
}