The Variable Stiffness Actuator vsaUT-II: Mechanical Design, Modeling, and Identification

Stefan Groothuis, Giacomo Rusticelli, Andrea Zucchelli, Stefano Stramigioli, Raffaella Carloni

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    133 Citations (Scopus)
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    In this paper, the rotational variable stiffness actuator vsaUT-II is presented. This actuation system is characterized by the property that the apparent stiffness at the actuator output can be varied independently from its position. This behavior is realized by implementing a variable transmission ratio between the internal elastic elements and the actuator output, i.e., a lever arm with variable pivot point position. The pivot point is moved by a planetary gears mechanism, which acquires a straight motion from only rotations, thereby providing a low-friction transmission. The working principle details of the vsaUT-II are elaborated and the design is presented. The actuator dynamics are described by means of a lumped parameter model. The relevant parameters of the actuator are estimated and identified in the physical setup and measurements are used to validate both the design and the derived model.
    Original languageUndefined
    Pages (from-to)589-597
    Number of pages9
    JournalIEEE/ASME transactions on mechatronics
    Issue number2
    Publication statusPublished - Apr 2014


    • EWI-23359
    • IR-86213
    • METIS-297645
    • CE-Advanced Robotics

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