Wenbo Li

Inspired by the geometry-mediated deformation mechanism of Viola seed capsules, this study proposes a high-contraction actuator composed of rhombic framework and stacked actuation units. The expansion of the stacked hydraulically amplified self-healing electrostatic units is mechanically converted by the rhombic frame into large axial contraction, enabling the local deformation of individual units to accumulate into a high overall contraction strain. Then, an analytical model based on geometric constraints and the minimum potential energy principle is developed to quantitatively predict the actuator output and validated through experiments. Furthermore, the effects of key design parameters and driving signals on the static response are systematically investigated. The proposed high-contraction rhombic electrohydraulic actuators demonstrate pronounced contraction capability, with an unloaded maximum steady-state contraction ratio approximately 100% and achieve a 42% linear contraction with 5 g load. These findings provide a new strategy for the design and application of compact and high-performance bioinspired soft actuators.

Organisms achieve adaptive survival through highly integrated closed‐loop systems of perception, feedback, and execution. This highly coordinated structure–function collaboration mode provides important inspiration for the design of soft robots. However, current intelligent soft robots are typically based on modular integration of discrete sensing and actuation units, making it difficult to achieve organism‐like highly coordinated full‐surface sensing–actuation coupling. As functionally tunable intelligent materials with high water content, softness, biocompatibility, and stimulus‐responsive behavior, hydrogels can integrate sensing and actuation into one material structure, which lays a material foundation for the development of next‐generation intelligent soft robotic systems. In this review, we comprehensively discuss the design requirements for hydrogels used in soft robots across different application fields in terms of material properties, sensing capabilities, and actuation functions. Based on the diverse functionalities of hydrogels, we emphasize the importance of integrating sensing and actuation, with particular attention to the evolutionary trajectory from the integration of discrete functional modules to structure–function integration and ultimately to closed‐loop feedback intelligent systems. Finally, we provide insightful perspectives on the current challenges and prospects in the field. This review aims to provide a systematic reference for the design and development of highly integrated, adaptive, and autonomous soft robotic systems.

Soft electrohydraulic actuators (SEHAs) represent a novel class of electrostatic‐driven soft actuators sharing a common working principle: the coupling of electrostatic actuation with dielectric liquid transmission or hydrodynamic actuation. As a result, SEHAs inherit the combined advantages of both actuation mechanisms, including high response speed, high force density, diverse actuation modes, silent operation, low power consumption, and minimal heat emission—attributes that have attracted much attention and applications in soft robotics and human‐machine interaction recently. This review provides the first holistic overview of SEHAs, with a primary focus on three categories classified according to the different coupling methods between electrostatic actuation and dielectric liquids: hydraulically amplified self‐healing electrostatic (HASEL), electro‐ribbon (ER), and electrohydrodynamic (EHD) actuators. We then compare and contrast their similarities and differences, while elaborating on their actuation mechanisms, structural designs tailored to different actuation modes, material selection strategies, fabrication techniques, and potential application scenarios. Finally, we discuss the key challenges and prospective research directions, including reducing operating voltage, enhancing actuation performance, and advancing integration and intelligent technologies for practical applications. This review is expected to provide guidance and inspiration for the high‐performance soft actuators, while continuously stimulating the innovation and application of SEHAs in next‐generation flexible electromechanical systems.

Controllable adhesive interfaces offer unique opportunities for dynamic object capture, especially for aerospace engineering. However, existing approaches often lack the capability to efficiently dissipate impact energy and rapidly protect the adhesive interface during rebound and typically rely on complex mechanical and control systems to fulfill multiple functions. Here, we present a sequential phase-switching adhesion strategy using shape memory polymers (SMPs) to facilitate full-cycle capture operations. The engineered SMP-frame adhesive structure captures targets with normalized kinetic energies exceeding 3800 joules per square meter, empowered by the intrinsic viscoelasticity of the material to provide both strong energy dissipation and rapid adhesive interface strengthening. The dynamic strengthening mechanism delays crack propagation and greatly enhances detachment toughness, enabling unprecedented rebound suppression within the short timescales of collision. The adhesive-integrated system successfully performs dynamic capture, manipulation, and release under free-floating conditions, demonstrating the effectiveness of the sequential phase-switching adhesion strategy. The proposed concept and design offer a paradigm for robust, multifunctional capture in high-dynamics environments.

Soft robots, with their compliant bodies, minimal environmental disturbance, and ability to withstand ambient pressures, offer promising solutions for deep-sea exploration. However, a common challenge of stiffening in soft materials impairs their effective actuation in harsh conditions. In this work, we integrated a liquid dielectric plasticizer within an electrohydraulic soft robot, serving dual critical functions as a softening agent to maintain the softness of the polymer shell and an electrohydraulic fluid for efficient actuation. In addition, by using the surrounding seawater as alternating electrodes, we prevented charge retention in dielectric layers, enabling sustained actuation performance. Field tests at depths of ~1360, 3176, and ~4071 meters confirmed the robot’s ability to sense the environment, navigate complex trajectories, and withstand unsteady disturbances. Our work offers a generalized and straightforward framework for developing soft materials tailored for deep-sea applications, paving the way for soft robots to execute real-world missions.

Soft robots are exceptionally suited to exploring complex environments, including amphibious navigations, due to their flexible and adaptive characteristics. However, achieving efficient actuation and multimodal locomotion or transition in amphibious environments for soft robots is challenging. In this paper, we present a multimodal amphibious robot with radial symmetry configuration and 3 different locomotion modes (crawling on land and underwater, swimming in water). The robot consists of 3 soft electrohydraulic flippers, which can be independently or synergistically actuated to rotate or oscillate in both air and water and generate the propulsion for amphibious locomotion. Theoretical analysis and experimental tests have verified the remarkable amphibious actuation performance of the soft electrohydraulic flippers with effective electrode encapsulation process. Optimal actuation frequencies are also obtained for maximizing the efficiency of the robot’s movements in different mediums. Based on the 3 powerful soft electrohydraulic flippers with radial symmetry distribution, the robot can smoothly transition from crawling on land to crawling underwater, and swim up from the bottom to the surface of water, without reconfiguration of the robot. This work demonstrates the first amphibious soft robot based on electrohydraulic actuators with multimodal locomotion transition in an amphibious environment and may open up more possibilities for the development of multimodal soft robots.

Active origami enabled by soft actuation has demonstrated excellent shape morphing and reconfiguration capability and unleashed great potential in many fields. However, available active origami structures or actuators usually have limited strain and speed, provide few active degrees of freedom or flexibility. Here, we report a multi-degree-of-freedom electrohydraulic origami (EHO) actuator with lightweight, high dynamic performance, flexibility and multi-functionality. We have achieved ultra large actuation strain (3300%) and strain rate (over 23500 % s^-1) for the actuators, and constructed various types of active deployable structures with programmable and rapid shape morphing controlled by the extension, rotation, translation folding or actuation modes of the actuator units. We also demonstrate three origami robots with high-speed bidirectional sliding, multi-directional jumping and crawling respectively based on the reconfiguration and shape morphing of the active origami structures. This study may accelerate the development and application of active origami towards high-speed and agile robotics.

Reconfigurable soft robots exhibit superior flexibility and adaptability when coping with complex environments and variable tasks. However, conventional modular design strategy based on soft actuator modules with specific structure and actuation mode as the basic constructing element for reconfigurable soft robots always has limited reprogrammability or scalability. Here, a hierarchical reconfigurable strategy is reported that not only offers conventional module reconfiguration as the first level to build different robot prototypes, but also provides the elastically‐guided multimodal actuation (contraction, bend, and twist) as the second level which can be reprogrammed to construct different actuator modules. This strategy deepens the modularity to a higher dimensionality and provides more choices for robots to adjust various conformations and functions as needed, for example, a peristalsis robot, an omnidirectional crawling robot, and a soft manipulator can be easily constructed using the module‐level reconfiguration. Moreover, soft manipulators with various preprogrammed deformation trajectories based on the mode reconfiguration are proven to dramatically reduce the operation difficulty and cost in potential applications such as environment detection and human‐robot interaction. This work provides a hierarchical framework for reconfigurable soft robots and may open up a new way for modular design.

Underwater soft robots inspired by marine life have shown great potential in ocean exploration, monitoring, scientific research, etc., due to their excellent safety, compatibility and adaptability when interacting with underwater environments. However, most of their soft actuators suffer performance degradation when operating in water, which leads to the limited cruising speed and maneuverability of underwater soft robots, especially for the electrically actuated ones. Here, we present a manta ray-inspired fast-swimming soft robotic fish based on a new kind of soft electrohydraulic actuator. Two pectoral fin-like actuators are symmetrically arranged to generate flapping motion and propel the robot. An improved electrode encapsulation strategy is proposed for promoting the underwater actuation performance for the actuators, which is also verified by the theoretical analysis, multi-physics simulation and experiments, respectively. The maximum underwater flapping angle can achieve 68 degrees for the encapsulated actuators which is very close to the angle in air. Based on the powerful and noise-free underwater actuation, the soft electrohydraulic robotic fish can swim at an average cruising speed of 111.2 mm/s (2.22 body lengths per second), substantially faster than most of the reported electrically driven soft robotic fish. The robot also has a maximum turning speed of 96°/s with a turning radius of 11.13 cm. This work suggests the high potential of soft electrohydraulic actuators for developing high-performance underwater soft robots, and applicability of our design and waterproof encapsulation strategy for underwater actuation scenarios.

Soft material‐based robots, known for their safety and compliance, are expected to play an irreplaceable role in human‐robot collaboration. However, this expectation is far from real industrial applications due to their complex programmability and poor motion precision, brought by the super elasticity and large hysteresis of soft materials. Here, a soft collaborative robot (Soft Co‐bot) with intuitive and easy programming by contact‐based drag teaching, and also with exceptional motion repeatability (< 0.30% of body length) and ultra‐low hysteresis (< 2.0%) is reported. Such an unprecedented capability is achieved by a biomimetic antagonistic design within a pneumatic soft robot, in which cables are threaded to servo motors through tension sensors to form a self‐sensing system, thus providing both precise actuation and dragging‐aware collaboration. Hence, the Soft Co‐bots can be first taught by human drag and then precisely repeat various tasks on their own, such as electronics assembling, machine tool installation, etc. The proposed Soft Co‐bots exhibit a high potential for safe and intuitive human‐robot collaboration in unstructured environments, promoting the immediate practical application of soft robots.