Feedback Control of a Compliant Bipedal Walker and Runner

MABEL Running

MABEL Running

Designing controllers that allow for robustly stable, energy efficient, and fast locomotion over unstructured terrain is essential for applications, such as first response, and disaster robotics. Our research contributes to the theoretical foundations of robotic bipedal locomotion and advances the experimental state of the art as well.

On the theoretical side, a mathematical formalism for designing provably stable, walking and running gaits in bipedal robots with compliance is developed. A key contribution is a novel method of force control in robots with compliance, which results in combining the analytical tractability afforded by the hybrid zero dynamics framework, with physically intuitive compliance control to induce reliable, fast running, as well as large unexpected step-down’s while walking. This is the first formal control design, with experimental validity, for bipedal runners with non-trivial morphologies.

On the experimental side, the designed controllers are validated on MABEL, a planar bipedal test bed with no feet, weighing 65 Kg, 1 m tall at the hips, and having a novel transmission with compliance. MABEL is a high degree-of-freedom, nonlinear, hybrid system, with several degrees of underactuation and subject to unilateral ground constraints. Current research has accomplished the following:

Publications

  1.  Embedding Active Force Control within the Compliant Hybrid Zero Dynamics to Achieve Stable, Fast Running on MABEL. Koushil Sreenath, Hae-Won Park, Ioannis Poulakakis, and Jessy W. Grizzle. The International Journal of Robotics Research (IJRR), 32(3):324--345, March 2013. pdf Video
    @article{ IJRR2013,
    author={ Koushil Sreenath and Hae-Won Park and Ioannis Poulakakis and Jessy W. Grizzle },
    title={ Embedding Active Force Control within the Compliant Hybrid Zero Dynamics to Achieve Stable, Fast Running on MABEL },
    journal={ The International Journal of Robotics Research (IJRR) },
    volume={ 32 },
    number={ 3 },
    pages={ 324--345 },
    month={ March },
    year={ 2013 },
    }
  2. Compliant Hybrid Zero Dynamics Controller for achieving Stable, Efficient and Fast Bipedal Walking on MABEL. Koushil Sreenath, Hae-Won Park, Ioannis Poulakakis, and Jessy W. Grizzle. The International Journal of Robotics Research (IJRR), 30(9):1170--1193, August 2011. pdf Video
    @article{ IJRR2011,
    author={ Koushil Sreenath and Hae-Won Park and Ioannis Poulakakis and Jessy W. Grizzle },
    title={ Compliant Hybrid Zero Dynamics Controller for achieving Stable, Efficient and Fast Bipedal Walking on MABEL },
    journal={ The International Journal of Robotics Research (IJRR) },
    volume={ 30 },
    number={ 9 },
    pages={ 1170--1193 },
    month={ August },
    year={ 2011 },
    }
  3. Identification of a Bipedal Robot with a Compliant Drivetrain: Parameter estimation for control design. Hae-Won Park, Koushil Sreenath, Jonathan Hurst, and Jessy W. Grizzle. IEEE Control Systems Magazine (CSM), 31(2):63--88, April 2011. This paper was the cover article on IEEE CSM, April 2011 issue. pdf Video
    @article{ CSM2011,
    author={ Hae-Won Park and Koushil Sreenath and Jonathan Hurst and Jessy W. Grizzle },
    title={ Identification of a Bipedal Robot with a Compliant Drivetrain: Parameter estimation for control design },
    journal={ IEEE Control Systems Magazine (CSM) },
    volume={ 31 },
    number={ 2 },
    pages={ 63--88 },
    month={ April },
    year={ 2011 },
    }
  4. Design and Experimental Implementation of a Compliant Hybrid Zero Dynamics Controller with Active Force Control for Running on MABEL. Koushil Sreenath, Hae-Won Park, and Jessy W. Grizzle. IEEE International Conference on Robotics and Automation (ICRA), pages 51--56, Saint Paul, MN, May 2012. pdf
    @conference{ ICRA2012a,
    author={ Koushil Sreenath and Hae-Won Park and Jessy W. Grizzle },
    title={ Design and Experimental Implementation of a Compliant Hybrid Zero Dynamics Controller with Active Force Control for Running on MABEL },
    booktitle={ IEEE International Conference on Robotics and Automation (ICRA) },
    pages={ 51--56 },
    month={ May },
    year={ 2012 },
    address={ Saint Paul, MN },
    }
  5. Switching Control Design for Accommodating Large Step-down Disturbances in Bipedal Robot Walking. Hae-Won Park, Koushil Sreenath, Alireza Ramezani, and Jessy W. Grizzle. IEEE International Conference on Robotics and Automation (ICRA), pages 45--50, Saint Paul, MN, May 2012. pdf Video
    @conference{ ICRA2012b,
    author={ Hae-Won Park and Koushil Sreenath and Alireza Ramezani and Jessy W. Grizzle },
    title={ Switching Control Design for Accommodating Large Step-down Disturbances in Bipedal Robot Walking },
    booktitle={ IEEE International Conference on Robotics and Automation (ICRA) },
    pages={ 45--50 },
    month={ May },
    year={ 2012 },
    address={ Saint Paul, MN },
    }
  6. Design and Experimental Implementation of a Compliant Hybrid Zero Dynamics Controller for Walking on MABEL. Koushil Sreenath, Hae-Won Park, Ioannis Poulakakis, and Jessy W. Grizzle. IEEE Conference on Decision and Control (CDC), pages 280--287, Atlanta, GA, USA, December 2010. pdf Video
    @conference{ CDC2010,
    author={ Koushil Sreenath and Hae-Won Park and Ioannis Poulakakis and Jessy W. Grizzle },
    title={ Design and Experimental Implementation of a Compliant Hybrid Zero Dynamics Controller for Walking on MABEL },
    booktitle={ IEEE Conference on Decision and Control (CDC) },
    pages={ 280--287 },
    month={ December },
    year={ 2010 },
    address={ Atlanta, GA, USA },
    }
  7. MABEL, A New Robotic Bipedal Walker and Runner. Jessy W. Grizzle, Jonathan Hurst, Benjamin Morris, Hae-Won Park, and Koushil Sreenath. American Control Conference (ACC), pages 2030--2036, St. Louis, MO, USA, June 2009. pdf Video
    @conference{ ACC2009,
    author={ Jessy W. Grizzle and Jonathan Hurst and Benjamin Morris and Hae-Won Park and Koushil Sreenath },
    title={ MABEL, A New Robotic Bipedal Walker and Runner },
    booktitle={ American Control Conference (ACC) },
    pages={ 2030--2036 },
    month={ June },
    year={ 2009 },
    address={ St. Louis, MO, USA },
    }