What is Soft Robotics?

Above image from Pneubotics.

Above image from Pneubotics.

Soft robotics describes an area of research building compliant actuators from soft-elastomers and textiles.  They are fluidic systems using fluids or air to actuate.  Soft robots offer unique benefits.  They are safer in proximity to humans as exoskeletons and manipulator arms.  They can handle delicate objects and spaces such as coral reefs.  They’re compliant, cost-effective, and light weight.

 

Soft Actuator Types


Soft Elastomeric Actuators

Soft elastomeric actuators are generally made up of molded silicone.  You might experiment with some of Smooth-on’s products for this.  In 2014, Harvard SEAS released a Soft Robotics Toolkit aimed at taking soft robotics open-sourced.  You can check it out here at http://softroboticstoolkit.com/ .  I do not recommend you try to build the cardiac simulator at home.  If you do, maybe don’t test it on anyone.

Visit the soft robotic toolkit site and you will find research videos.  Like this multi-gait demo from the Whitesides Research Group.

 

 

MCKIBBENS

Sometimes these actuators are referred to as Pneumatic Artificial Muscles, sometimes McKibbens air muscles.  This type of actuator was invented in the 50s.  The design is simple. They’re made up of an outer braid which is long and narrow under load and an internal bladder.  When the bladder is filled, the braid expands in width and shrinks in length.  Again, the Harvard site shows the simplest construction of a McKibben.  You can fabricate your own following their Fabrication steps.

You can find soft robotics video tutorials, like the one below, by XYZAidan.  He is currently working at Super Releaser.

 

MULTIFILAMENT MUSCLES

 

Multifilament Muscles that look like a series of strings, used by University of Tokyo, are made form a series of narrow Mckibbens actuators.  For their gait model, they used OpenSim.

 

 

FABRIC ACTUATORS

At Otherlab they skip the molded silicone and go for fabric with an air-tight bladder.  This is much like the construction of a kite-surfing kite.  I could talk more than I should about these actuators, as I know them intimately.  There are two projects at Otherlab working on this technology.  Pneubotics is building manipulator arms and Roam Robotics is building exoskeletons.  For high entertainment value, check out the Otherlab Channel on Youtube.

 

 

Bowden Cable Actuators

 

Harvard's Exosuit uses Bowden cable style actuators for gait assistance.

Check out the biodesign lab at Harvard to read more about these devices.

 

Tensegrity Robots

Another example of robotics actuated by tensioning steel cables is at NASA.  The Intelligent Robotics Group has been experimenting with possibilities in soft robotics for years.  With tensegrity robots, they're able to actuate a collapsible structure.  These robots can handle hard landings and are mobile in variable terrain.

 

Knitted Exoskeletons

At Drexel University, they're using Shima Seiki Knitting Machines to knit gloves with embedded actuation.  "The Exo-Skin is controlled by an Arduino-based system communicating via serial link with the nearest computer or Bluetooth enabled device. For human-computer interaction applications, the “Leap Motion” sensor provides sub-millimeter accurate location information to place the user's hand within a computational 3D space."

 

APPLICATIONS

 

Deep Sea Exploration

Soft robotic grippers are gentle with delicate objects and environments.

 

Soft Exoskeletons and Exosuits

DARPA created an initiative called Warrior Web to create an exoskeleton that would assist in improving the abilities of soldiers especially during load carriage.  Read more about the Warrior Web Project.  To learn more about different companies and academic institutions working in this space, check out this article on Exoskeleton Report.

 

Rehabilitative Devices

A full exoskeleton may not be necessary for specific use cases.  Smaller devices that are local to the area being treated may be more impactful.

Harvard has created a Soft Robotic Glove from their soft elastomeric actuators. 

 

Industry

PROTOTYPING

 

The field of soft robotics is open for exploration by anyone interested.  Fellow RISD Alumni, Matthew Borgatti, founded Super Releaser.  Which is a prototyping lab in Brooklyn, NY to make soft robotics for clients such as: Google X, NASA, and SOLS.  Super Releaser also has made several of their in-house projects open source.

 

COMMERCIALIZATION:

 

Soft Robotics Inc

One of the few companies that is commercializing soft robotics, is called Soft Robotics Inc.  They make end effectors meant for use in warehousing, food handling, and advanced assembly.

 

Empire Robotics

Empire has created a soft robotic end effector called Versaball, which used vacuum to grip small objects.  This Jimmy Fallon parody gives an example of it working with ping pongs.  The capabilities extend from grasping objects as large as smart phones and light bulbs to objects the size of pills.

 

 

Soft Robotics Journal

You can read the peer reviewed soft robotics journal to learn about state of the art publication and research in this space.

 

IEEE Spectrum Robotics News

Follow the Robotics thread for news and updates in the Robotics community, like this Octo-bot from The BioRobotics Institute at Sant'Anna School of Advanced Studies in Italy.

 

Tools of the Trade

OpenSim

OpenSim is described as: "OpenSim is a powerful and freely available tool for modeling and simulation of movement. Watch the video below to get an overview of the project and see how OpenSim can be used to help plan surgery for children with cerebral palsy." Understanding gait and other movements is critical for Soft Robotics Exoskeleton applications particularly for rehabilitation.

 

Soft Actuator Design Tool

At École Polytechnique Federale De Lausanne, the Reconfigurable Robotics Lab has released a software for designing soft actuators using FEM.  You can also read more about it at Harvard's Soft Robotics Toolkit.