Development of a prototype of a novel spherical mechanism with a parallel kinematical structure and redundant actuation, developed in continuation of my MSc thesis with fellow students at Czech Technical University.

Spherical mechanism HexaSphere was developed as an alternative to traditional Cardan hinge. As an over-actuated mechanism with parallel kinematical structure, it has a large singularity-free workspace (±100°) with potentially high stiffness, accuracy, and fast dynamics. The following videos present the mechanism prototype and its achievable workspace as well as demonstration applications:

For more details, visit the HexaSphere project website.

Related publications:

  • [DOI] M. Valášek, J. Zicha, M. Karásek, and R. Hudec, “Hexasphere—Redundantly Actuated Parallel Spherical Mechanism as a New Concept of Agile Telescope,” Advances in Astronomy, vol. 2010, p. 1–6, 2010.
    abstract = {{\textless}p{\textgreater} The paper deals with the description of a new concept for a spherical mechanism for agile telescopes. It is based on redundantly actuated parallel kinematical structure. Due to the three times overactuated structure and application of several further innovative concepts, the Hexasphere achieves the movability of {\textless}math{\textgreater} {\textless}mo{\textgreater}±{\textless}/mo{\textgreater} {\textless}/math{\textgreater} 100 degrees. This enables the use of a Hexasphere as the basis for mounts of telescopes. Such telescopes can be optimized for minimum weight or for maximum dynamics. The proposed mechanism is expected to play a role in novel robotic telescopes nowadays used in many fields of astronomy and astrophysics, with emphasis on automated systems for alert observations of celestial gamma-ray bursts. {\textless}/p{\textgreater}},
    author = {Val{\'{a}}{\v{s}}ek, Michael and Zicha, Josef and Kar{\'{a}}sek, Mat{\v{e}}j and Hudec, Rene},
    doi = {10.1155/2010/348286},
    issn = {1687-7969},
    journal = {Advances in Astronomy},
    pages = {1--6},
    publisher = {Hindawi Publishing Corporation},
    title = {{Hexasphere—Redundantly Actuated Parallel Spherical Mechanism as a New Concept of Agile Telescope}},
    url = {http://www.hindawi.com/journals/aa/2010/348286/},
    volume = {2010},
    year = {2010}
  • M. Karásek and M. Valášek, “Mechatronic Spherical Joints for Increased Mobility,” in Computational Mechanics, Hrad Nectiny, Czech Republic, 2009, p. 8.
    address = {Hrad Nectiny, Czech Republic},
    author = {Kar{\'{a}}sek, Mat{\v{e}}j and Val{\'{a}}{\v{s}}ek, Michael},
    booktitle = {Computational Mechanics},
    pages = {8},
    title = {{Mechatronic Spherical Joints for Increased Mobility}},
    year = {2009}
  • M. Valášek and M. Karásek, “Kinematical Analysis of HexaSphere,” in Engineering Mechanics 2009, Svratka, Czech Republic, 2009, p. 8.
    address = {Svratka, Czech Republic},
    author = {Val{\'{a}}{\v{s}}ek, Michael and Kar{\'{a}}sek, Mat{\v{e}}j},
    booktitle = {Engineering Mechanics 2009},
    pages = {8},
    title = {{Kinematical Analysis of HexaSphere}},
    year = {2009}
  • M. Karásek, “Model aktivního sférického kloubu (Model of Active Spherical Joint), MSc thesis,” Czech Technical University in Prague 2008.
    author = {Kar{\'{a}}sek, Mat{\v{e}}j},
    institution = {Czech Technical University in Prague},
    pages = {66},
    title = {{Model aktivn{\'{i}}ho sf{\'{e}}rick{\'{e}}ho kloubu (Model of Active Spherical Joint), MSc thesis}},
    year = {2008}