A problem with traditional hard robots is their inability to hold or grip or move objects less dense than they are. These robots either lack the ability to grip, or they grip so non-compliantly they crush whatever’s in their grasp. In essence, they cannot interact effectively with real-world situations – like packaging soft materials or interacting with humans in a medical scenario.
Enter soft robotics. Soft robotics can interact more effectively and safely with humans, unknown objects and rough terrain – anything more compliant or non-linear.
New fabrication technologies that allow for the combination of hard and soft materials necessary for actuators, sensors and soft robotic casings. Constructing a robot from compliant materials, such as elastomers or stretchy plastics, gives them a far greater ability to interact with objects less rigid than they are.
Several universities are pushing the boundaries of soft gripper mechanisms, haptic object visualization, and origami-style robots – one of which is the University of California, San Diego’s Bioinspired Robotics and Design Lab.
Gecko-inspired adhesive grippers:
The importance and the challenge of a gripping mechanism that’s both compliant and receptive cannot be understated. Mike Tolley, Ph.D, leads the UC San Diego’s Bioinspired Robotics and Design Lab, and tests elastomer actuators for the gripping surface of robots powered by internal fluid pressure. Tolley mimics the gecko’s toe behavior to achieve high strength grasps with near instant actuation for both large and small objects. The trick here is that the fluid actuators enable an even gripping pressure across the structure so that an object can be uniformly grasped.
Soft robotic gripper sensor skins for haptic object visualization:
Adapting to changing or uncertain environments is a problem for robots. Tolley and his team have been studying sensors capable of recognizing complex motions.
His team assembles what amount to robotic “fingers” that can be inflated independently. Their results are approaching soft robot grippers capable of a complex range of motions and proprioception, which will help future robots better understand the environments with which they interact. Read more about explicitly how these are developed in this eBook.
3D printed soft fluidic actuators
Fluid is known to be one of the best compliance substances and Tolley and his team are working with fluidically actuated soft robots in unknown environmental conditions. Typically, fluidic actuators are inefficient, expensive and/or prone to leaks. The Robotics and Design Lab has devised a way to use not only pressure or vacuum as a means of actuation but also differential press actuation. The technological advancements in 3D printing materials allow Tolley’s team to 3D print soft robotic modules.
3D printed soft actuators for a legged robot on unstructured terrain
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UCSD developed a four-legged robot capable of walking over uneven surfaces is in preparation for exploration of terrains inhospitable to humans, such as deserts or rock faces. This type of soft robot is particularly well-suited to being deployed in search-and-rescue operations.
The legs of the robot are designed based on a bellows system, where each ‘bubbled’ segment is connected to the other allowing air to pass through. Air is provided by a system of tubes connecting to the top of the body, creating a tarantula-like movement as the compartments are emptied and filled.
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The legs were printed with a Stratasys Object 350 Connex 3 system using a combination of the rubbery TangoBlackPlus and rigid VeroClear, giving the desired consistency for friction moving over a surface, and stability to keep the robot upright.
Read more about the design of the robot here.
Soft robotic glove for kinesthetic haptic feedback in virtual reality
Sensory feedback is vital in the virtual reality world. Current versions of robotic gloves are rigid, which aren’t conducive to interactivity. Tolley’s team is working on a wearable soft robotic glove that can actually apply force to the fingers of the user.
Origami-style robots
Tolley’s team is also working with untethered quadruped soft robots and fabrication by folding, or origami-style soft robotics, drawing from nature again but until recently, lacking the material and fabrication capabilities now available to them through the use of multi-material 3D printing.
The potential applications for soft roboritcs far-reaching implications in medicine, disaster recovery, warehouse and distribution, agriculture and more.
Get up-to-speed on these applications across a range of industries and learn more about UCSD’s Bioinspired Robotics and Design Lab’s work by downloading Stratasys’ Robotics Inspiration Guide, 3D Printing Your Way From Idea to Application eBook.
