IEEE Robotics & Automation Magazine - March 2016 - 43

Conclusion
Inspired by the principle of learning through practice, we applied a sampling-based search to optimize locomotion controllers that significantly expand the repertoire of motion skills for
StarlETH, our quadruped robot. We addressed the high-dimensional, nonsmooth nature of the locomotion control problem by finding a good tradeoff between feedforward motion
primitives, which are optimized based on the design of the
robot, and robust state-feedback control, which compensates
for modeling errors and sensor noise and rejects unanticipated
disturbances. We showed that by appropriately modeling the
contact and actuator dynamics of our compliant quadruped,
the simulation-based optimization results were directly applicable to the real platform. Based on our results, we believe that
our approach constitutes an important step toward a fully automatic solution for generating behaviors and motion skills for
a wide variety of legged robots. To promote further work in
this area, we have open-sourced our implementation of the
state estimator and motion controller, both of which can be
found on our website: http:// leggedrobotics.ethz.ch.
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Christian Gehring, Swiss Federal Institute of Technology,
Zurich, Switzerland. E-mail: gehrinch@ethz.ch.
Stelian Coros, Carnegie Mellon University, Pittsburgh, Pennsylvania, United States. E-mail: scoros@andrew.cmu.edu.
Marco Hutter, Swiss Federal Institute of Technology, Zurich,
Switzerland. E-mail: mahutter@ethz.ch.
C. Dario Bellicoso, Swiss Federal Institute of Technology,
Zurich, Switzerland. E-mail: bellicosodario@gmail.com.
Huub Heijnen, Swiss Federal Institute of Technology, Zurich,
Switzerland. E-mail: hheijnen@student.ethz.ch.
Remo Diethelm, Swiss Federal Institute of Technology, Zurich,
Switzerland. E-mail: rdiethelm@gmail.com.
Michael Bloesch, Swiss Federal Institute of Technology, Zurich,
Switzerland. E-mail: bloeschm@ethz.ch.
Péter Fankhauser, Swiss Federal Institute of Technology,
Zurich, Switzerland. E-mail: pfankhauser@ethz.ch.
Jemin Hwangbo, Swiss Federal Institute of Technology, Zurich,
Switzerland. E-mail: jhwangbo@ethz.ch.
Markus A. Hoepflinger, Swiss Federal Institute of Technology, Zurich, Switzerland. E-mail: hoepflinger@mavt.ethz.ch.
Roland Siegwart, Swiss Federal Institute of Technology, Zurich,
Switzerland. E-mail: rsiegwart@ethz.ch.

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Table of Contents for the Digital Edition of IEEE Robotics & Automation Magazine - March 2016
