Reprogrammable, intelligent soft origami LEGO coupling actuation, computation, and sensing

Design and Motion Analysis of a Soft Modular Robot for Diverse Environments

This article introduces the design and development of a modular soft robot capable of performing multiple movement modes. The core unit module features a four-chamber soft structure, separated by a cross-shaped thin plate. By selectively applying pneumatic pressure to different chambers and changing connector configurations, the robot achieves diverse modular configurations and movement modes, enabling it to adapt to various environments. To address the challenges posed by the material's nonlinear behavior and its infinite degrees of freedom, a three-dimensional spatial mathematical modeling approach is proposed. This method, grounded in classical plate theory and the chained composite model, establishes a static model for the soft robot's spatial bending motion with constant curvature. In addition, a single-controller framework based on a central pattern generator is developed to facilitate the generation of multiple movement gaits. By tuning parameters such as oscillator phase, frequency, load factor, and amplitude, the controller can generate a wide range of movement patterns. To validate the proposed theoretical and experimental models, we developed a pneumatic control platform that demonstrated the robot's multimodal locomotion capabilities through systematic testing in terrains with varying complexity.

Reversible and Programmable Wettability of Laser-Induced Graphene Papers via In Situ Joule Heating-Triggered Superslippery Surfaces

Reversible surface materials with programmable wettability play an increasingly vital role in a wide variety of fields from science to industry. Based on laser-induced graphene (LIG) technology, we innovatively propose a paraffin-infused porous LIG paper (P-LIGP) with tunable superslippery wettability. On account of graphene's excellent electrical property, paraffin in P-LIGP can transit rapidly from a solid-to-liquid state in response to the in situ Joule heating effect. Thus, a LIGP surface is created with a dynamic and reversible transition between slippery and nonslippery state. In addition, combining the patternable performance with tunable LIGP resistance, the paraffin layer from P-LIGP can be selectively melted based on Ohm's law and Kirchhoff's laws, thus enabling special flow pathways with programmable wettability for manipulating the droplets with various straight/oblique/arc/S-shaped sliding patterns. These applications with customizable LIG resistance performance promise the in situ Joule heating of P-LIGP for designing intelligent and flexible temperature-responsive surfaces.

Printing Untethered Self-Reconfigurable, Self-Amputating Soft Robots from Recyclable Self-Healing Fibers

Regarding the challenge of self-reconfiguration and self-amputation of soft robots, existing studies mainly focus on modular soft robots and connection methods between modules. Different from these studies, this study focus on the behavior of individual soft robots from a material perspective. Here, a kind of soft fibers, which consist of hot melt adhesive particles, magnetizable microparticles, and ferroferric oxide microparticles embedded in a thermoplastic polyurethane matrix are proposed. The soft fibers can achieve wireless self-healing and reversible bonding of the fibers by eddy current heating and can be actuated by magnetic fields. Moreover, the soft fibers are recyclable and printable. Building on this material foundation, an integrated material-structure-actuation printing strategy using soft fibers for the design and fabrication of soft robots are reported. The robots printed by this strategy can achieve their untethered motions and wireless self-healing. Soft gripper, soft crawling robot, and soft multi-legged robot, are then fabricated which demonstrates the self-healing, self-reconfigurable, self-amputating, and sustainable performances of soft robots so as to adapt to different environments and tasks. This integrated material-structure-actuation printing strategy using soft fibers is universal, easy to implement, and mass-manufactured, opening a door for sustainable, eco-friendly, untethered, self-reconfigurable, self-amputating soft robots.

Tri-Prism Origami Enabled Soft Modular Actuator for Reconfigurable Robots

Soft actuators hold great potential for applications in surgical operations, robotic manipulation, and prosthetic devices. However, they are limited by their structures, materials, and actuation methods, resulting in disadvantages in output force and dynamic response. This article introduces a soft pneumatic actuator capable of bending based on triangular prism origami. The origami creases are crafted by utilizing fabrics to gain swift response and fatigue-resistant properties. By connecting two actuators in series, combined motions including extension and diversified compound bending can be achieved, facilitating control in complex scenarios. After modularizing the soft actuator via mortise and tenon structures, several actuators can be programmed to execute a variety of intricate tasks by adjusting the timing sequences of their contraction and expansion. We showcase its applications in reconfigurable robots, and the results confirm that such a design is adequate for flexibly performing tasks such as soft gripping, navigational movement, and obstacle avoidance. These findings highlight the significance of our actuator in developing soft robots for versatile tasks.

An intelligent spinal soft robot with self-sensing adaptability

Self-sensing adaptability is a high-level intelligence in living creatures and is highly desired for their biomimetic soft robots for efficient interaction with the surroundings. Self-sensing adaptability can be achieved in soft robots by the integration of sensors and actuators. However, current strategies simply assemble discrete sensors and actuators into one robotic system and, thus, dilute their synergistic and complementary connections, causing low-level adaptability and poor decision-making capability. Here, inspired by vertebrate animals supported by highly evolved backbones, we propose a concept of a bionic spine that integrates sensing and actuation into one shared body based on the reversible piezoelectric effect and a decoupling mechanism to extract the environmental feedback. We demonstrate that the soft robots equipped with the bionic spines feature locomotion speed improvements between 39.5% and 80% for various environmental terrains. More importantly, it can also enable the robots to accurately recognize and actively adapt to changing environments with obstacle avoidance capability by learning-based gait adjustments. We envision that the proposed bionic spine could serve as a building block for locomotive soft robots toward more intelligent machine-environment interactions in the future.

Variable Stiffness Fibers Enabled Universal and Programmable Re-Foldability Strategy for Modular Soft Robotics

Origami is a rich source of inspiration for creating soft actuators with complex deformations. However, implementing the re-foldability of origami on soft actuators remains a significant challenge. Herein, a universal and programmable re-foldability strategy is reported to integrate multiple origami patterns into a single soft origami actuator, thereby enabling multimode morphing capability. This strategy can selectively activate and deactivate origami creases through variable stiffness fibers. The utilization of these fibers enables the programmability of crease pattern quantity and types within a single actuator, which expands the morphing modes and deformation ranges without increasing their physical size and chamber number. The universality of this approach is demonstrated by developing a series of re-foldable soft origami actuators. Moreover, these soft origami actuators are utilized to construct a bidirectional crawling robot and a multimode soft gripper capable of adapting to object size, grasping orientation, and placing orientation. This work represents a significant step forward in the design of multifunctional soft actuators and holds great potential for the advancement of agile and versatile soft robots.