IDEAS home Printed from
MyIDEAS: Log in (now much improved!) to save this paper

Dynamic Gravity Cancellation and Regulation Control in Robots with Flexible Transmissions: Constant, Nonlinear, and Variable Stiffness

Listed author(s):
  • Alessandro De Luca


    (Dipartimento di Informatica e Sistemistica "Antonio Ruberti" Sapienza, Universita' di Roma)

  • Fabrizio Flacco


    (Dipartimento di Informatica e Sistemistica "Antonio Ruberti" Sapienza, Universita' di Roma)

Registered author(s):

    We consider the problem of perfect cancellation of gravity effects in the dynamics of robot manipulators having flexible transmissions at the joints. Based on the feedback equivalence principle, we aim at designing feedback control laws that let the system outputs behave as those of the same robot device when gravity is absent. The cases of constant stiffness (elastic joints), nonlinear flexible, and variable nonlinear flexible transmissions with antagonistic actuation are analyzed. As a particular case, antagonistic actuation with transmissions having constant but different stiffness is also considered. In all these situations, viable solutions are obtained either in closed algebraic form or by a simple numerical technique. The compensated system can then be controlled without taking into account the gravity bias, which is particularly relevant for safe physical human-robot interaction tasks where such compliant manipulators are commonly used. Moreover, dynamic gravity cancellation allows to design new PD-type regulation controllers and to show their global asymptotic stability without the need of any positive lower bound neither on the stiffness nor on the proportional control gain. A Lyapunov-based proof is provided for the case of robots with elastic joints. Simulation results are reported to illustrate the obtained performance in the various robotic systems with flexible transmissions.

    If you experience problems downloading a file, check if you have the proper application to view it first. In case of further problems read the IDEAS help page. Note that these files are not on the IDEAS site. Please be patient as the files may be large.

    File URL:
    Download Restriction: no

    Paper provided by Department of Computer, Control and Management Engineering, Universita' degli Studi di Roma "La Sapienza" in its series DIS Technical Reports with number 2010-11.

    in new window

    Date of creation: 2010
    Handle: RePEc:aeg:wpaper:2010-11
    Contact details of provider: Phone: +390677274140
    Fax: +39 0677274129
    Web page:

    More information through EDIRC

    No references listed on IDEAS
    You can help add them by filling out this form.

    This item is not listed on Wikipedia, on a reading list or among the top items on IDEAS.

    When requesting a correction, please mention this item's handle: RePEc:aeg:wpaper:2010-11. See general information about how to correct material in RePEc.

    For technical questions regarding this item, or to correct its authors, title, abstract, bibliographic or download information, contact: (Antonietta Angelica Zucconi)

    If you have authored this item and are not yet registered with RePEc, we encourage you to do it here. This allows to link your profile to this item. It also allows you to accept potential citations to this item that we are uncertain about.

    If references are entirely missing, you can add them using this form.

    If the full references list an item that is present in RePEc, but the system did not link to it, you can help with this form.

    If you know of missing items citing this one, you can help us creating those links by adding the relevant references in the same way as above, for each refering item. If you are a registered author of this item, you may also want to check the "citations" tab in your profile, as there may be some citations waiting for confirmation.

    Please note that corrections may take a couple of weeks to filter through the various RePEc services.

    This information is provided to you by IDEAS at the Research Division of the Federal Reserve Bank of St. Louis using RePEc data.