Robotics

Read here about tensegrity structures used in the construction of robots. Skelton, Shai and Vytas SunSpiral are leading researchers on the topic, harnessing tensegrity in order to implement flexibility, dynamism and light-weighting in their robotic structures.

Pages on Robotics in this Wiki

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People investigating Tensegrity and Robotics

A list of people investigating tensegrity and robotics, in no particular order:

• Robert E. Skelton, Structural Systems and Control Laboratory, Department of Mechanical & Aerospace Engineering, University of California, San Diego. Link: http://maeweb.ucsd.edu/~skelton/

• Offer Shai, Department of Solid Mechanics, Materials and Structures, Faculty of Engineering, Tel Aviv University, Israel. Link: http://www.eng.tau.ac.il/~shai/

• Vytas SunSpiral at NASA ARC, Principal Investigator, Adrian Agogino. Link: http://www.nasa.gov/directorates/spacetech/niac/2012_phase_I_fellows_agogino.html

• Alice Agogino at BEST Lab , UC Berkeley. Link: http://best.berkeley.edu/

• Saeed Behzadipour, Advanced Robotics and Control Systems Lab, Mechanical Engineering Department, University of Alberta. Link: http://www.ualberta.ca/~saeedb/index.htm

• Shinichi Hirai, Tensegrity Robots, Deptartment of Robotics, Ritsumeikan University, Shiga, Japan. Link: http://www.ritsumei.ac.jp/se/~hirai/research/tensegrity-e.html

• Ryan Meuth, Professor of Robotics and Embedded Systems, University of Advancing Technology in Tempe, AZ. Link: http://www.uat.edu/academics/faculty_bios.aspx

• Tensegriteam, University of Idaho. Link: http://seniordesign.engr.uidaho.edu/2010-2011/tensegriteam/index.html

Selected Videos of Tensegrity-based Robotics

Lecture by SunSpiral' on tensegrity robotics:

Tensegriteam's Tensegrity-based modular robotic arm is presented at Idaho's annual engineering design Expo.

Selected Readings in Tensegrity Robotics

Selected readings that discuss the application of tensegrity to the field of robotics.

Tensegrities and Caterpillars

What Tensegrities and Caterpillars Can Teach Us About Soft Robotics by Rieffel, Trimmer, Lipson Link: http://www.scribd.com/doc/35313582/What-Tensegrities-and-Caterpillars-Can-Teach-Us-About-Soft-Robotics-by-Rieffel-Trimmer-Lipson

John Rieffel, Barry Trimmer and Hod Lipson address robotic locomotion via dynamic tensegrity structure. They discuss that tensegrity embodies ”morphological computation,” where actuation and control of the structure is embodied within the structural dynamics of the robot itself. The biological musculoskeletal system is thought to work in this way, as is cellular biomechanics. In this paper the authors review some details of a catepillar's anatomy and locomotion as it pertains to morphological computation. They then present related work in which a highly complex mechanical system – a tensegrity structure – is able to achieve locomotion by exploiting the dynamical coupling between modules as an emergent data bus. Finally, they bring these aspects together when describing the design and control of a completely soft robot modeled loosely on the manduca. Their goal is to present morphological computation – the use of mechanism as mind – as the best approach to solving the issues of actuation and control inherent in soft robotics. The examples of morphological computation that they bring - one from biology, the manduca sexta caterpillar, and one from engineering, a modular tensegrity tower - bring the design of a highly articulate, under-controlled, soft robot closer to fruition.

Locomotion of a Tensegrity Robot

Locomotion of a Tensegrity Robot via Dynamically Coupled Modules by Rieffel, Stuk, Cuevas Lipson Link: http://www.scribd.com/doc/29350905/Locomotion-of-a-Tensegrity-Robot-via-Dynamically-Coupled-Modules-by-Rieffel-Stuk-Cuevas-Lipson

Tensegrity structures - dynamically stable systems consisting of disjoint rigid elements (rods) connected by tensile elements (strings) - are an intriguing robotic platform due to their relatively high strength-to-weight ratio, resilience to deformation, and collapsability. Furthermore, the homogeneity of the rigid elements lends itself to a modular design . However, for any such design which requires centralized control, as the scale of these robots increases, inter-modular communication becomes a challenge (not just in terms of logistics, but also in the risk of tangled wires during locomotion). An alternative proposed here is to treat each module as a completely autonomous agent, with no explicit inter-modular communication between them. Rather, the only information transmitted and received between modules is through the tension on their respective strings. As such, locomotion arises through the complex interplay of dynamical forces throughout the structure. In this extended abstract we describe a design for such a system, present an assembled model, and describe a means by which controllers can be evolved in order to produce locomotion.

Gait Production in a Tensegrity Based Robot

Gait Production in a Tensegrity Based Robot by Paul, Roberts, Lipson, Cuevas Link: http://www.scribd.com/doc/29350770/Gait-Production-in-a-Tensegrity-Based-Robot-by-Paul-Roberts-Lipson-Cuevas

The design of legged robots for movement has usually been based on a series of rigid links connected by actuated or passively compliant joints. However, the potential utility of tensegrity, in which form can be achieved using a disconnected set of rigid elements connected by a continuous network of tensile elements, has not been considered in the design of legged robots. This paper introduces the idea of a legged robot based on a tensegrity1, and demonstrates that the dynamics of such structures can be utilized for locomotion. A mobile robot based on a triangular tensegrity prism is presented, which is actuated by contraction of its transverse cables. The automatic design of a controller architecture for forward locomotion is performed in simulation using a genetic algorithm which demonstrates that the structure can generate multiple effective gait patterns for forward locomotion. A real world tensegrity robot is implemented based on the simulated robot, which is shown to be capable of producing forward locomotion. The results suggest that a tensegrity structure can provide the basis for extremely lightweight and robust mobile robots.

Tensegrity and Robotic Movement Overview

Robots Growing Up, Tensegrity and Robotic Movement by Earnhardt Link: http://www.scribd.com/doc/35312931/Robots-Growing-Up-Tensegrity-and-Robotic-Movement-by-Earnhardt-PPT-Notes

A general overview of the application of tensegrity concepts to robotics.

Design and Control of Tensegrity Robots for Locomotion

Design and Control of Tensegrity Robots for Locomotion by Paul, Cuevas Lipson Link: http://www.scribd.com/doc/35269799/Design-and-Control-of-Tensegrity-Robots-for-Locomotion-by-Paul-Cuevas-Lipson Link: http://www.scribd.com/doc/35311717/Design-and-Control-of-Tensegrity-Robots-for-Locomotion-by-Paul-Cuevas-Lipson

Abstract—The static properties of tensegrity structures have been widely appreciated in civil engineering as the basis of extremely lightweight yet strong mechanical structures. However, the dynamic properties and their potential utility in the design of robots have been...

Planar Tensegrity Structures

Planar Tensegrity Structures for Robotic Applications by Schmalz A thesis submitted to the Faculty of the University of Delaware in partial fulfillment of the requirements for the degree of Master of Science in Mechanical Engineering, Fall 2006

Link: http://www.scribd.com/doc/35312833/Planar-Tensegrity-Structures-for-Robotic-Applications-by-Schmalz

Robot Tensegrity Structure Crawling

Crawling by Body Deformation of Tensegrity Structure Robots, by Mizuho Shibata, Fumio Saijyo, and Shinichi Hirai, 2009 IEEE International Conference on Robotics and Automation Kobe International Conference Center Kobe, Japan, May 12-17, 2009,

In this paper, the authors describe the design of a deformable robot with a tensegrity structure that can crawl. Rresults of experiments showing the ability of these robots to crawl are shown. Link: http://www.scribd.com/doc/35312881/Robot-Tensegrity-Structure-ICRA2009shibataTensegrity Link: http://www.scribd.com/doc/29350564/Crawling-by-Body-Deformation-of-Tensegrity-Structure-Robots-by-Shibata-Saijyo-Hirai

Aerial, Terrestrial and Aquatic Microbots

Aerial, Terrestrial and Aquatic Microbots by Wood Link: http://www.scribd.com/doc/35190347/Aerial-Terrestrial-and-Aquatic-Microbots-by-Wood

A powerpoint presentation on tiny flying robots. includes review of the 0.1g MFI, the 0.06g Harvard Microrobotic Fly, the fixed wing MAV and others. Tensegrity exoskeletons or airframes are sought as they are thought to be efficient and lightweight. Other topics covered include robotic fish, battery issues and more.

Planar Tensegrity Structures

Planar Tensegrity Structures for Robotic Applications by Schmalz Link: http://www.scribd.com/doc/35522946/Planar-Tensegrity-Structures-for-Robotic-Applications-by-Schmalz

Andrew Peter Schmalz's thesis submitted to the Faculty of the University of Delaware, fall 2006. In a typical robotic control methods, links are activated that can supply both tensile and compressive force. In tensegrity devices, however, these are strictly isolated: a tendon cannot communicate a compressive force to the structure. Schmalz focuses on planar tensegrity structures as he finds they have only two Cartesian two dimensions to analyze. In planar structures, rods may possess at most three degrees of freedom (two translational, one rotational) making dynamic analysis considerably simpler than with three dimensional models that have six degrees of freedom. Schmalz analyzes robotic arms and deployable structures. His discussion proceeds in chapters. Chapter 2 elaborates his classification scheme and outlines his assumptions. Chapter 3 develops aspects of control for tensegrity systems, focussing on the constraint mentioned above, that that positive tensions be maintained in all cables. A solution is found using redundant cables. Chapter 4 gives workspaces, meaning configurations a tensegrity structure may reach from a given initial state while maintaining tensions which are within a specified range. Such workspaces have not yet been defined for tensegrity systems. Chapter 5 presents experimental results including reports of physical models that were constructed. For more information, see http://tensegrity.wikispaces.com/Portal+To+Robotics

Morphological Communication

J. R. Soc. Interface-2010-Rieffel-613-21 Link: http://www.scribd.com/doc/29350942/Morphological-Communication-J-R-Soc-Interface-2010-Rieffel-613-21

Traditional engineering approaches strive to avoid, or actively suppress, nonlinear dynamic coupling among components. Biological systems, in contrast, are often rife with these dynamics. Could there be, in some cases, a benefit to high degrees of dynamical coupling? Here we present a distributed robotic control scheme inspired by the biological phenomenon of tensegrity-based mechanotransduction. This emergence of morphology-as-informationconduit or ‘morphological communication’, enabled by time-sensitive spiking neural networks, presents a new paradigm for the decentralized control of large, coupled, modular systems. These results significantly bolster, both in magnitude and in form, the idea of morphological computation in robotic control. Furthermore, they lend further credence to ideas of embodied anatomical computation in biological systems, on scales ranging from cellular structures up to the tendinous networks of the human hand.