Soft robotics

Soft Robotics is a subfield of robotics that deals with robots built out of soft and deformable material like silicone, plastic, fabric, rubber, or compliant mechanical parts like springs. Soft robots can actively interact with the environment and can undergo “large” deformations relying on inherent or structural compliance respectively due to the softness or the morphological features of its body.

Aspects of Soft Robots

Soft robots are often, but not necessarily, bio-inspired and are known to have a number of advantages over classical robotic devices based on traditional robotic technologies. Soft and deformable structures are crucial in systems that deal with uncertain and dynamic tasks and environments, e.g. grasping and manipulation of unknown objects, locomotion in rough terrain, and physical contact with

living cells and human bodies[3].

Disadvantages of soft robots are that soft structures are difficult to model and, therefore, complicated to control.

“Soft” may refer to the structural compliance of a robot, that means that the softness comes from ad hoc geometrical arrangements and morphology of hard materials – so that structural strains are magnified compared with local material deformation (e.g. compliant mechanisms). Several industrial robots use compliant mechanisms, such as the KUKA Lightweight Robot (LWR) that is characterized by a low mass-payload ratio and a programmable, active compliance.

“Soft” may also refer to an inherent material compliance that involves bulk material properties – including soft matter (e.g. elastomers, polymers, gels, etc.), which guarantee a safe interaction with the environment. As an example of soft robots, the soft

silicone-based caterpillar robot inspired by the manduca sexta, the GoQBot[4], exploits SMA (Shape Memory Alloy) actuators and the incompressibility of fluids to deliver performance resembling those of the hydrostatic skeletons. The octopus-inspired robots (OCTOPUS (http://www.octopus-project.eu), OctoProp (http://sssa.bioroboticsinstitute.it/projects/CFD-OctoProp) and PoseiDRONE (http://sssa.bioroboticsinstitute.it/projects/PoseiDRONE)) combine the use of soft materials, SMA actuators and cable driven transmission to

accomplish dexterous manipulation by artificial muscular hydrostats[5][6], legged locomotion[7] and swimming by jet propulsion[8],

and use the same principles of octopus vulgaris with a biomimetic design approach[9][10]. The STIFF-FLOP (http://www.stiff-flop.eu) endoscopic device represents another octopus-inspired robot that combines high dexterity and stability thanks to the combination of a

pneumatic actuation and a granular jamming based mechanism[11].

At Harvard University a series of soft robots based on pneumatic actuation has been developed, such as starfish-like[12] and tentacle-

like robots[13], which show large deformation and even camouflage capability. The JamBots (http://jfi.uchicago.edu/~jaeger/group/Soft_Robotics/Details/Entries/2009/8/28_JamBot__A_new_type_of_soft_robot.html) are

another example of how soft materials in combination with soft actuation technologies can be used for robot locomotion[14] and grasping[15]. In JamBots, the material properties can be changed with granular jamming (determining anisotropies) and motion can be

generated with pneumatic actuators or with cable-driven systems, as in the case of the MIT jammable manipulator[16]. Soft and flexible materials can be also be part of the actuation system itself as in the case of the use of EAP (ElectroActive Polymers) in the

starfish-like robot[17] or in the tissue-engineered multi-limbed medusoid robot[18], or in the Meshworm robots where a series of SMA springs arranged in antagonistic manner supported by a flexible braided mesh-tube structure is used to produce a peristaltic motion[19].

Examples of Soft Robots

Here is a list of examples of soft robots (in alphabetical order)

• Soft under-actuated fish robots developed in the Mechanical Engineering Department at MIT [2] (http://newsoffice.mit.edu/2009/robo- fish-0824)
• Octopus robot developed in the EU project OCTOPUS (http://www.octopus-project.eu)
• Stiffness controllable flexible and learn-able manipulator for surgical operations STIFF-FLOP (http://www.stiff-flop.eu/the-project) Soft caterpillar inspired robot from Tufts University [3] (http://www.sciencedaily.com/releases/2007/01/070128105355.htm)
• Soft starfish inspired robot developed by Robert Shepherd (http://www.mae.cornell.edu/people/profile.cfm?netid=rfs247) (Cornell University), see [20] Untethered quadruped soft robot developed by Michael Tolley (http://michaeltolley.com) (UC San Diego) et al., see [2]
• SMART/MIT soft batoids and sensors [4] (http://www.nrf.gov.sg/scientific-advances/science-spotlight/marine-wonderland-in-motion)
• Roboy (http://roboy.devanthro.com) - a tendon driven robot developed by the Artificial Intelligence Laboratory of the University of Zurich
• JamBot (http://jfi.uchicago.edu/~jaeger/group/Soft_Robotics/Details/Entries/2009/8/28_JamBot__A_new_type_of_soft_robot.html) - locomotion based on granular jamming
• GoQBot
• CFD-OctoProp (http://sssa.bioroboticsinstitute.it/projects/CFD-OctoProp)
• PoseiDRONE (http://sssa.bioroboticsinstitute.it/projects/PoseiDRONE)
• ECCE robot (http://eccerobot.org)
• FILOSE

Scientific Community

Although people have been using soft material for robots for a long time, only recently an international community has been formed. For example, since October 2012 exists an IEEE RAS Technical Committee on Soft Robotics (http://www.ieee-ras.org/soft-robotics), which coordinates the international community around this field of research. In 2013 the International Journal on Soft Robotics (http://www.liebertpub.com/soro) was funded. It publishes quarterly results from the field. In October 2013 started RoboSoft (http://www.robosoftca.eu) – A Coordination Action for Soft Robotics funded by the European Commission under the 7th Framework Programme, Future and Emerging Technologies (FET) Open Scheme. RoboSoft aims at creating and consolidating an international scientific community of scientists and roboticists working in the field of soft robotics to combine their efforts and enable the accumulation and sharing of scientific and technological knowledge to maximize the opportunities and materialize the huge potential impact of soft robotics technologies.

International Journals

• Soft Robotics (SoRo) (http://www.liebertpub.com/soro)
• Soft Robotics section of Frontiers in Robotics and AI (http://journal.frontiersin.org/journal/robotics-and-ai/section/soft-robotics)

International Events

• 2016 Soft Robotics week, Livorno, Italy
• 2015 Soft Robotics: Actuation, Integration, and Applications - Blending research perspectives for a leap forward in soft robotics technology (http://robotics.oregonstate.edu/icra2015softrobotics), 2015 IEEE International Conference on Robotics and Automation (ICRA), Seattle WA, May 2014
• 2014 Workshop on Advances on Soft Robotics (http://www.robosoftca.eu/events/rss2014-workshop), 2014 Robotics Science an Systems (RSS) Conference, Berkeley, CA, July 13, 2014
• 2013 International Workshop on Soft Robotics and Morphological Computation (http://www.softrobot2013.ethz.ch), Monte Verità, July 14-19, 2013
• 2012 Summer School on Soft Robotics (http://www.birl.ethz.ch/sssr2012%7CETH), Zurich, June 18-22, 2012