Embedded shape morphing for morphologically adaptive robots.

Shape-morphing robots can change their morphology to fulfill different tasks in varying environments, but existing shape-morphing capability is not embedded in a robot's body, requiring bulky supporting equipment. Here, we report an embedded shape-morphing scheme with the shape actuation, sensing, and locking, all embedded in a robot's body. We showcase this embedded scheme using three morphing robotic systems: 1) self-sensing shape-morphing grippers that can adapt to objects for adaptive grasping; 2) a quadrupedal robot that can morph its body shape for different terrestrial locomotion modes (walk, crawl, or horizontal climb); 3) an untethered robot that can morph its limbs' shape for amphibious locomotion. We also create a library of embedded morphing modules to demonstrate the versatile programmable shapes (e.g., torsion, 3D bending, surface morphing, etc.). Our embedded morphing scheme offers a promising avenue for robots to reconfigure their morphology in an embedded manner that can adapt to different environments on demand.

On-demand, remote and lossless manipulation of biofluid droplets.

The recent global outbreaks of epidemics and pandemics have shown us that we are severely under-prepared to cope with infectious agents. Exposure to infectious agents present in biofluids (e.g., blood, saliva, urine etc.) poses a severe risk to clinical laboratory personnel and healthcare workers, resulting in hundreds of millions of hospital-acquired and laboratory-acquired infections annually. Novel technologies that can minimize human exposure through remote and automated handling of infectious biofluids will mitigate such risk. In this work, we present biofluid manipulators, which allow on-demand, remote and lossless manipulation of virtually any liquid droplet. Our manipulators are designed by integrating thermo-responsive soft actuators with superomniphobic surfaces. Utilizing our manipulators, we demonstrate on-demand, remote and lossless manipulation of biofluid droplets. We envision that our biofluid manipulators will not only reduce manual operations and minimize exposure to infectious agents, but also pave the way for developing inexpensive, simple and portable robotic systems, which can allow point-of-care operations, particularly in developing nations.

Twisted-and-Coiled Actuators with Free Strokes Enable Soft Robots with Programmable Motions.

Various actuators (e.g., pneumatics, cables, dielectric elastomers, etc.) have been utilized to actuate soft robots. Besides widely used actuators, a relatively new artificial muscle-twisted-and-coiled actuators (TCAs)-is promising for actuating centimeter-scale soft robots because they are low cost, have a large work density, and can be driven by electricity. However, existing works on TCA-actuated soft robots in general can only generate simple bending motion. The reason is that TCAs fabricated with conventional methods have to be preloaded to generate a large contraction, and thus cannot actuate soft robots properly. In this work, an upgraded technique is presented to fabricate TCAs that can deliver 48% free strokes (contraction without preloading). We first compare the static performance of TCAs with free strokes with conventional TCAs, and then characterize how will the fabrication parameters influence the TCAs' stroke and force capability. After that, we demonstrate that such TCAs can actuate centimeter-scale soft robots with programmable motions (gripping, twisting, and three-dimensional bending). Finally, we combine those motions to demonstrate a soft robotic arm that can perform a pick-and-place task. We expect that TCAs with free strokes can enable miniature soft robots with rich three-dimensional motions for both locomotion and manipulation. Because TCAs are electrically driven, we can also potentially develop untethered soft robots by carrying onboard batteries and control circuits.

Leveraging elastic instabilities for amplified performance: Spine-inspired high-speed and high-force soft robots.

Soft machines typically exhibit slow locomotion speed and low manipulation strength because of intrinsic limitations of soft materials. Here, we present a generic design principle that harnesses mechanical instability for a variety of spine-inspired fast and strong soft machines. Unlike most current soft robots that are designed as inherently and unimodally stable, our design leverages tunable snap-through bistability to fully explore the ability of soft robots to rapidly store and release energy within tens of milliseconds. We demonstrate this generic design principle with three high-performance soft machines: High-speed cheetah-like galloping crawlers with locomotion speeds of 2.68 body length/s, high-speed underwater swimmers (0.78 body length/s), and tunable low-to-high-force soft grippers with over 1 to 103 stiffness modulation (maximum load capacity is 11.4 kg). Our study establishes a new generic design paradigm of next-generation high-performance soft robots that are applicable for multifunctionality, different actuation methods, and materials at multiscales.