Themed collection Soft Robotics

Anand Kumar Mishra, Zhihong Nie, Jamie Paik and Robert Shepherd introduce the Soft Matter themed issue on Soft Robotics.

The creation of highly effective oral drug delivery systems (ODDSs) has long been the main objective of pharmaceutical research.

Compared to traditional rigid-bodied robots, soft robots are constructed using physically flexible/elastic bodies and electronics to mimic nature and enable novel applications in industry, healthcare, aviation, military, etc.

The seamless integration of multiple units greatly enhances the functionalities and adaptability of miniature soft robots. This review delivers the recent progress in multicomponent and multifunctional integrated miniature soft robots.

Electrically driven liquid crystal network (LCN) actuators, combining the merits of electrical modulation and the great actuation properties of LCN, have been advanced towards practical applications, new robotic functions and advanced motion control.

The swelling of a hydrogel can exert enormous osmotic swelling stress, which can be harnessed to achieve robust hydrogel actuators. A hydrogel jack that can lift a weight 2000 times its own weight is demonstrated.

Soft 3D-printable adhesive elastomers with self-healing capabilities were formulated. These materials were 3D printed into complex structures and used to modify soft robots for shape-selective lifting.

We propose a novel sensorless estimation method for soft pneumatic actuators through injecting pressure oscillations and monitoring pressure response. We demonstrate this approach by sensing force and displacement without use of dedicated sensors.

Stiffness modulation is paramount in the design of soft robotics and magnetorheological jamming beams, which combine magnetorheological fluid with scaffolding material, providing a novel method for achieving magnetically tunable stiffening ranges.

Examining the properties of amorphous entangled systems through in silico simulations and in living aggregates of worm blobs, large-amplitude changes of the particle's shape improve the entanglement and tensile strength of the collective.

We propose a neural architecture to make sense of the nonlinear relationship between the perceived intensity of the magnetic field and the shape of a continuum soft robot and improve efficiency by injecting priori knowledge from a kinematic model.

Here, we report soft electrochemical systems that could enable pump-free pneumatic actuation. Besides, the electrochemical approach requires only a few volts to actuate, unlike dielectric actuators, which require ∼kV.

A thin, fully-soft, and stretchable variable stiffness device through electrorheological fluid was proposed, which could conform to complex surfaces in its inactive state, hang on it in its active state, and detach when the electric field is removed.

This paper describes an analytical formulation of the deformation of an ellipsoid soft membrane, applied to a purely mechanically driven haptic feedback system, in particular, to the membrane of the fingertip sensor.

E-skins consisting of soft pressure sensors are enabling technology for soft robots, bio-integrated devices, and deformable touch panels.

We present a method of 3D printing handed shearing auxetics for scalable, motorized soft robotic actuators. The auxetics are assembled into multi-degree-of-freedom legs that enable fast, untethered locomotion over long operation times.

Orthogonal actuation for power and control in untethered small-scale machines is achieved with self-powered protein chemical motors and plasticized liquid crystal networks.

An earthworm-inspired soft-burrowing robot with a 3D-printed artificial hydrostatic skeleton.

Liquid metal soft composite morphology is quantified through X-ray scattering and real-space image analysis, providing global-averaged particle size and size distributions for material design.

TiO₂ particles are added into silicone matrices to develop highly reflective composite coatings. Coated soft optical waveguides and strain sensors demonstrate superior environmental light shielding, and tolerance to bending, folding, and indentation.

We have developed a magnetic vitrimer-based soft robot that can pass through a confined space, dramatically change its configuration, self-heal without any contact, catch, secure and release a fast-moving object, and move along a planned path.

In this work, we report 3D printable soft composites that are simultaneously stretchable and tough.

The InFoam method combines liquid rope coiling and regular plotting to fabricate structures softer than their original material and with graded porosity. This combination can be used to realize soft robotics structures such as soft fluidic actuators.

The stretchable and adhesive liquid-free ionic conductive elastomers were developed and assembled into triboelectric nanogenerators for use as human–machine interactive keyboards.

Dielectric elastomer actuators (DEAs) are soft electromechanical transducers for robotic applications. We report a method to continuously monitor high voltage capacitance during DEA actuation to directly measure the electrical energy consumption.

A new soft 3D printable elastomer allows for improvements to soft pneumatic actuators that can both expand and contract under different pressures. The actuators exhibit excellent performance metrics and are shown to be viable in soft mobile robots.