RSS 2015 Workshop

Robotic Uses for Tails

July 17th, 2015

Aaron M. Johnson*, D. E. Koditschek†
*: Robotics Institute, Carnegie Mellon University, USA
†: GRASP Lab, University of Pennsylvania, USA

Tails and tail-like appendages have shown the potential to greatly enhance robot agility, enabling such feats as leaping over broken rubble [1–3], making hairpin turns [4–6], and responding dynamically to disturbances [7–9]. Recently there has been an explosion in new robot designs that feature tail-like appendages, ranging in scale from a few grams [3,5] to tens of kilograms [7]. Tails have been used on robots with many vastly different morphologies, including wheeled [1,4], bipedal [3,9], quadrupedal [7], hexapedal [2,5,6,8], and even flying [10] platforms. These robots have been inspired by the even greater variety in the form and function of tails in nature, as exhibited, for example, by moths [10], lizards [1,11], kangaroos [9], cheetahs [4,7], and dinosaurs [12]. Researchers are only beginning to understand the fundamental trade-offs involved in either adding a new limb or reusing an existing limb for some inertial, aerodynamic, or gyroscopic benefit. Whereas these initial studies suggest that tails are not a mere novelty but may really provide a useful new affordance in locomotion, no broad conclusion can yet be drawn from the limited instances of illustrative behaviors in specific scenarios.

Workshop Organization:
This workshop seeks to push toward a more comprehensive and systematic approach to the problem domain by bringing together many of the roboticists and biologists who have begun to explore tail-like appendages. The format will consist of a number of invited and contributed presentations on cutting edge research in the field, as well as an open discussion prompted by the questions listed below. Invited speakers will include some researchers already active in the area, e.g. [1–12], as well as some that work in related fields such as legged locomotion, dynamic manipulation, and biomechanics. The organizers will assign a chair to each session who will be responsible for reading in advance the material to be presented. In addition to moderating questions from the workshop participants, the chair will raise specific questions prepared in advance of each speaker after their talk. Beyond these question periods between speakers, a dedicated discussion session in the afternoon will provide a venue to summarize the conclusions of the day's proceedings and consider the future and potential of this line of research. A few discussion questions will be sent to the presenters and listed on the workshop website in advance so that participants can have time to prepare and consider their answers. Presenters will also be encouraged to touch on the following set of overarching topics in their talks.

Workshop Organization:

This workshop seeks to push toward a more comprehensive and systematic approach to the problem domain by bringing together many of the roboticists and biologists who have begun to explore tail-like appendages. The format will consist of a number of invited and contributed presentations on cutting edge research in the field, as well as an open discussion prompted by the questions listed below. Invited speakers will include some researchers already active in the area, e.g. [1–12], as well as some that work in related fields such as legged locomotion, dynamic manipulation, and biomechanics.
The organizers will assign a chair to each session who will be responsible for reading in advance the material to be presented. In addition to moderating questions from the workshop participants, the chair will raise specific questions prepared in advance of each speaker after their talk. Beyond these question periods between speakers, a dedicated discussion session in the afternoon will provide a venue to summarize the conclusions of the day's proceedings and consider the future and potential of this line of research. A few discussion questions will be sent to the presenters and listed on the workshop website in advance so that participants can have time to prepare and consider their answers. Presenters will also be encouraged to touch on the following set of overarching topics in their talks.

Discussion Questions:
What sorts of behaviors could benefit most from the use of tails or other appendages?
What are the costs of a tail-like appendage to an animal or robot and when are the benefits truly worth the cost?
What remains unknown about the use of tails in biology or robotics?

Program/Schedule:
Presenting author marked with a *
8:30 - 9:00 Welcome: Overview, Prospects, and Challenges
9:00 - 10:30 Session 1: Observing Tail Use in Animals (Chaired by Tom Libby)
Amir Patel* and Edward Boje	On the Conical Motion and Aerodynamics of the Cheetah Tail
Tonia Hsieh*	Impacts of Tail Loss and Surface Breadth on Running Stability in a Tree-Dwelling Lizard
Bruno Grossi and Javier Ruiz-del-Solar*	Dinosaurs, Robots and Tails
Andrew Spence*	The Jockey as a Tail: How Can a Jockey Influence Horse Performance?
10:30 - 11:00 Break
11:00 - 12:30 Session 2: Experiments with Robotic Tails (Chaired by Pei-Chun Lin)
Matt Estrada and Mark Cutkosky*	The Tail of KlingOn
Garrett J. Wenger*, Avik De, and Daniel E. Koditschek	Roll Stabilization on a Tailed Biped
Ivan Penskiy*, C. Casarez, A. Fein, and S. Bergbreiter	Bio-Inspired Tail in Miniature Robots
Kamilo Melo*, T. Horvat, R. Tandiackal, and A. Ijspeert	Use of Tails in Amphibious Locomotion
12:30 - 2:30 Lunch
2:30 - 4:00 Session 3: Modeling and Understanding Tail Function (Chaired by Mark Cutkosky)
Chad Kessens* and Craig T. Lennon	Robotic Uses of Tails: Self-Righting
Tom Libby*, A. Johnson, R. Full, and D. Koditschek	Design and Comparative Morphology for Inertial Reorientation
Po-Wei Tseng and Pei-Chun Lin*	Motion Optimization of a Planar Kangaroo Model
Sangbae Kim*	Momentum Control Using Limbs, Tails in Mobile Robots: Challenges and Tradeoffs
4:00 - 4:30 Break
4:30 - 6:00 Discussion Session

List of Speakers:
Mark Cutkosky, Stanford University
Tonia Hsieh, Temple University
Chad Kessens, U.S. Army Research Labs
Sangbae Kim, Massachusetts Institute of Technology
Tom Libby, University of California, Berkeley
Pei-Chun Lin, National Taiwan University
Kamilo Melo, École Politechnique Fédérale de Lausanne (EPFL)
Amir Patel, University of Cape Town
Ivan Penskiy, University of Maryland
Javier Ruiz-del-Solar, Universidad de Chile
Andrew Spence, Temple University
Garrett Wenger, University of Pennsylvania

Important Dates:
May 15th - Early-bird registration deadline for RSS
June 15th - 1 page extended abstract and talk titles due
July 13–17th - RSS Conference
July 17th - Workshop

Resources:
Robotics: Science and Systems (RSS) 2015
RSS 2015 Workshop Information
RSS 2015 Registration Information
Throwing Your Weight Around: Using Appendage Inertia (CLAWAR 2012 Special Session)

References:
[1] E. Chang-Siu, T. Libby, M. Tomizuka, and R. J. Full, "A lizard-inspired active tail enables rapid maneuvers and dynamic stabilization in a terrestrial robot," in Intelligent Robots and Systems, San Fransisco, CA, USA, Sept. 2011.
[2] A. M. Johnson, T. Libby, E. Chang-Siu, M. Tomizuka, R. J. Full, and D. E. Koditschek, "Tail assisted dynamic self righting," in Proceedings of the International Conference on Climbing and Walking Robots, Baltimore, USA, July 2012, pp. 611-620.
[3] J. Zhao, T. Zhao, N. Xi, F. J. Cintron, M. W. Mutka, and L. Xiao, "Controlling aerial maneuvering of a miniature jumping robot using its tail," in Intelligent Robots and Systems (IROS), 2013 IEEE/RSJ International Conference on. IEEE, 2013, pp. 3802-3807.
[4] A. Patel and M. Braae, "Rapid turning at high-speed: Inspirations from the cheetah's tail," in Intelligent Robots and Systems (IROS), 2013 IEEE/RSJ International Conference on. IEEE, 2013, pp. 5506-5511.
[5] C. Casarez, I. Penskiy, and S. Bergbreiter, "Using an inertial tail for rapid turns on a miniature legged robot," in Robotics and Automation (ICRA), 2013 IEEE International Conference on. IEEE, 2013, pp. 5469-5474.
[6] N. Kohut, A. Pullin, D. Haldane, D. Zarrouk, and R. Fearing, "Precise dynamic turning of a 10 cm legged robot on a low friction surface using a tail," in Robotics and Automation (ICRA), 2013 IEEE International Conference on. IEEE, 2013, pp. 3299-3306.
[7] R. Briggs, J. Lee, M. Haberland, and S. Kim, "Tails in biomimetic design: Analysis, simulation, and experiment," in Intelligent Robots and Systems (IROS), 2012 IEEE/RSJ International Conference on. IEEE, 2012, pp. 1473-1480.
[8] J. Ackerman, X. Da and J. Seipel, "Mobility of legged robot locomotion with elastically-suspended loads over rough terrain," in Proceedings of the International Conference on Climbing and Walking Robots, Baltimore, USA, July 2012.
[9] Guan-Horng Liu, Hou-Yi Lin, Huai-Yu Lin, Shao-Tuan Chen, Pei-Chun Lin, "A Bio-Inspired Hopping Kangaroo Robot with an Active Tail," Journal of Bionic Engineering, Volume 11, Issue 4, October 2014, Pages 541–555.
[10] A. Demir, M. M. Ankarali, J. P. Dyhr, K. A. Morgansen, T. L. Daniel and N. J. Cowan, "Inertial redirection of thrust forces for flight stabilization," in Proceedings of the International Conference on Climbing and Walking Robots, Baltimore, USA, July 2012.
[11] A. Jusufi, D. T. Kawano, T. Libby, and R. J. Full, "Righting and turning in mid-air using appendage inertia: reptile tails, analytical models and bio-inspired robots," Bioinspiration & Biomimetics, vol. 5, no. 4, p. 045001, 2010.
[12] T. Libby, T. Y. Moore, E. Chang-Siu, D. Li, D. J. Cohen, A. Jusufi, and R. J. Full, "Tail-assisted pitch control in lizards, robots and dinosaurs," Nature, vol. 481, no. 7380, pp. 181-184, 2012.