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Introducing Jeff Friesen — Tensegrity Robot Designer Extraordinaire

I would like to take the opportunity to highlight the work of Jeff Friesen, one of the most talented robot designers I have had the pleasure to work with!  He is a PhD student at UCSD in the Coordinated Robotics Lab, who has been working with our lab both as a summer student, and as a central part of our team for the last few years with the support of a NASA Space Technology Research Fellowships (NSTRF).  Jeff is delightfully talented at mechatronic design and controls algorithms, and has built a number of very innovative tensegrity robots over the years.  With his rapid iteration on building new robots, he has encountered and addressed a number of unique design challenges that are common to many tensegrity robots, and a number of his ideas have been integrated into our current SUPERball 2.0 robot designs (which he also participated in developing).

While some of Jeff’s most innovative and impactful work is waiting for publication, I would like to highlight one of the  robots that Jeff developed over a couple years and through two design iterations,

Jeff Friesen’s Duct Climbing Tetrahedral Tensegrity (DuCTT) Robot

namely the Duct Climbing Tetrahedral Tensegrity (DuCTT) Robot.  The intent of the robot was to develop a machine which could climb and maneuver through tight constrained spaces, such as ducts in buildings, or small tunnels or natural crevasses.  The challenge is to  be able to both lift and move in a vertical shaft, while also being able to turn corners.  Because most duct systems (and all natural tunnels) have complex internal features, simply using wheels to roll along is not sufficient, but instead requires that the system be able to lift and place limbs of some sort.  In attempting to address all these requirements with more traditional designs, past efforts have generally resulted in overly complex mechanisms which are too heavy or fragile for real use.

As is often the case, designing a robot with tensegrity principles in mind, Jeff was able to develop a simple and light weight solution which can climb and turn as required.  The system is composed of 2 tetrahedral sections, connected by a network of cables, which enable the sections to inchworm up the shaft.  In fact, there could be as many modules as needed, if a longer robot with different payloads or sensors was required.   Each tetrahedron has a linear motor in one of the bars to control the width of the tetrahedron,  allowing it to press and hold firmly against the shaft, or tuck in compactly to move around an obstacle.  This next video shows DuCTT climbing up out of a vertical shaft.

Since it is a bit hard to see all the details of how the robot moves, the next animated video (based on the first generation robot) shows how the inchworm action occurs.

Finally, the following video shows DuCTT exercising its full range of motion, which shows how it could turn a corner within a duct system.

For more information about this robot, see the following papers:

Jeffrey Michael Friesen, Michael Fanton, Paul Glick, Pavlo Manovi, Alexander Xydes, Thomas Bewley, Vytas SunSpiral, “The Second Generation Prototype of A Duct Climbing Tensegrity Robot, DuCTTv2”, In proceedings of 2016 IEEE International Conference on Robotics and Automation, (ICRA2016), May 2016, Stockholm, Sweden. Download PDF.

Jeffrey Michael Friesen, Alexandra Pogue, Thomas Bewley, Mauricio de Oliveira, Robert E. Skelton, Vytas SunSpiral, “A Compliant Tensegrity Robot for Exploring Duct Systems”, In Proceedings of International Conference on Robotics and Automation (ICRA), Hong Kong, June 2014 Download PDF.



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Interviews, Media Coverage, and Deep Learning

There has been some nice media coverage of our Tensegrity Robotics research “recently”. I’m a bit behind on updating this blog, so “recent” really means “in the last 6 months” or so.

Most exciting is an interview by Zygote Quarterly. This is a magazine dedicated to bio-inspired design, and the interview gives some nice insights into how I’ve found inspiration in fusing engineering and biological inspiration in developing the field of tensegrity robotics. And since it is a design magazine, its really pretty with some nice inspirational photos. Worth the read!

Next, back in January the BBC released a nice short video about our research. I always appreciate when someone does independent research and pulls together a story including prior videos and information we have released. It is so refreshing to see given how much of online media is slapped together with minimal effort and is often wildly inaccurate, especially around science topics. As usual, the BBC continues to maintain standards for real content. Thanks!

And, now to give this post some more fun technical content — back in May we presented a Tensegrity Deep Learning paper at the International Conference on Robotics and Automation (ICRA) that was developed jointing with our colleagues at UC Berkeley who led the algorithm development. In it we demonstrated the first example of learned continuous locomotion on the actual SUPERball robot. What is particularly amazing is that we were able to do all the training in simulation, and have the learned policy work directly on the real robot. This is unusual in the world of robotics, and I believe that it highlight the value of flexible, compliant robots like our tensegrity robot — the compliance that makes it resilient to unexpected contact also makes it robust to approximately tuned controllers. You can read the paper, find the code, and more on the project website.

Or just watch the video here:

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My 2016 NASA Ames Summer Series Presentation: SUPERball: A Biologically Inspired Robot for Planetary Exploration

Back in June of 2016 I was very honored to be invited to present as part of the NASA Ames Summer Series. Each summer, the Office of the Chief Scientist at NASA Ames produces a lecture platform with leaders whose high achievements generate innovative discussion, as well as inspire and catalyze scientific progress. This year, the Summer Series consisted of 18 seminars by lecturers from NASA Ames Research Center, external NASA staff, as well as renowned colleagues who lectured on topics that span across multiple advanced subject areas including space technology and space exploration. It was an honor to be included in the lecture series!

Exploration and Innovation both require bold leaps into the unknown, beyond the boundaries of current knowledge and experience. Exploring the unknown frontiers of space requires resilient and adaptable robots capable of surviving the unexpected, qualities which humans excel at. Moving beyond the traditional designs for rigidly constructed fragile robots, Vytas draws inspiration from the flexible tensile network of muscle and tendons of our bodies to develop a new class of “Dynamic Tensegrity Robots.” His current project, SUPERball, is intended to survive high-speed landings without an airbag, and thus enable exploration of treacherous terrains where slipping and falling is an unavoidable possibility. These new robots break the rules of traditional robotics engineering, requiring innovation at all levels of mechanical design, actuation, sensing, and control strategies. Modern neuroscience provides insights into how decentralized rhythmic controllers can enable self-organizing control strategies for this new class of biologically inspired robot and provides insight into our core human qualities of thought, motion, inspiration, and our essential ability to see connections between people and ideas which is at the heart of innovation.

Vytas SunSpiral is an entrepreneurial researcher moving fluidly between leading startups and building research labs to explore cutting edge robotic and AI technologies. He is a Fellow of the NASA Innovative Advanced Concepts (NIAC) program,, and currently leads the Dynamic Tensegrity Robotics Lab (DTRL) within the Intelligent Robotics Group at NASA Ames Research Center. His research spans a multi-disciplinary fusion of robotics, physiology, AI, mechatronics, and neuroscience, with the goal of understanding human intelligence via the foundational role that motion plays in our evolution. This quest led to a fundamental new approach to robotics that has the potential to reinvent how we explore the solar system. He is an author of ~50 journal and conference articles and was a contributing author of the 2013 Roadmap for US Robotics. Over the last 20 years he has also been the Founder, CTO, and Advisor to multiple startups, including Mobot, which sold the worlds first commercially available autonomous tour guide robots. Vytas holds a Masters in Computer Science and a BA in Symbolic Systems from Stanford University.

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New Video Highlighting Jonathan Bruce’s Research

Jonathan Bruce is a UC Santa Cruz PhD student who has been a central member of my lab for many years now. He has been instrumental to all of our successes, and is a gifted mechatronics engineer who is pushing the boundaries of tensegrity robotics design and control. The UARC program is a mechanism by which UC Santa Cruz and other UC campuses collaborate with NASA Ames, and they recently choose to highlight his innovative work and contribution to NASA’s research success. They sent a film crew to interview him and get context on our broader research project, including our collaboration with the BAIR and BEST labs at UC Berkeley. The resulting video is a *really* excellent overview of our research and well worth watching.

Finally: A Big THANK YOU to Jonathan for all his contributions!
Check out the many Journal and Conference publications he has led or co-authored.

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