Soft robotics最新文献

Biohybrid robots actuated by living cells/tissues, a soft robot system that integrates many advantages of life systems and mechanical systems, are promising candidates for developing a new generation of biomedical and environmental monitoring robots. However, due to the limited muscle contraction performance and lack of flexible muscle contraction modes, biohybrid robots' low speed and flexibility have become a major challenge for their application. To overcome the limitation, different from the existing contraction mode along the longitudinal axis with pulse stimulation, we firstly adopted the square wave stimulation on triceps femoris tissue with pennate fibers arrangement from bullfrogs and found a novel muscle swinging mode with high flexibility and controllability. Based on it, we developed a biomimetic crawler actuated by triceps femoris tissue. The crawler achieved fast forward movement (average speed: ∼6.19 mm/s; maximum speed: ∼7.35 mm/s) and flexible turning ability (∼14.77°/s and ∼9.55°/s for left and right turning speed, respectively) in a liquid environment at room temperature. We believe that the results provide valuable references for the development of soft robots driven by muscle tissue and pave the way to fulfill lifelike motions and break through limitations in conventional biohybrid robots.

This article presents a method for modifying the propagation speed of deformation waves on a thermoplastic bistable lattice, which consists of multiple bistable structures mechanically connected in a chain. This can be achieved by altering the energy difference between its stable states using thermal bending. Unlike traditional methods requiring material or structural changes, the proposed approach dynamically switches the propagation speed without disassembly. In contrast to magnetic and pneumatic control methods, the thermally tunable bistable lattice requires no external magnetic field, pumps, or tubing and adds minimal extra mass, enabling in situ and local retuning of the propagation speed while preserving a simple, compact system architecture. A caterpillar-like robot, composed of four pairs of oppositely arranged legs, each actuated by a bistable structure, was used to demonstrate the efficacy of the proposed method. The robot achieves crawling locomotion using only a single motor, as the leg movements are sequentially triggered through mechanical propagation of deformation, with the propagation speed tunable via the thermal treatment. Experimental results showed that slower wave propagation enhanced locomotion on a 45° incline by increasing rail grip, achieving a climbing speed of 0.95 mm/s. These results highlight the unique advantages of thermally tunable bistable lattices over conventional actuation schemes and contribute to the development of soft robots capable of adaptive locomotion in unstructured environments such as pipeline/conduit inspection and endoluminal/endoscopic navigation.

With the rapid development of soft robotics, there is a growing demand for compact, high-performance, and flexible actuators. Pneumatic actuators are particularly favored by researchers due to their high efficiency, low cost, and ease of fabrication. However, the existing pneumatic actuators are faced with challenges such as large volume, low actuating frequency, and insufficient propulsion. For the first time, this work presents a novel thin-plate pneumatic actuator based on prestressed principles, featuring an efficient energy storage and release mechanism. The actuator consists of a prestretched layer, a constrained layer, and a chamber (PCC), with a total thickness of less than 1 mm. Therefore, the elastic potential energy is preserved in the prestretched film within the actuator body, which enables high actuating frequency and large propulsion. Effects of key structural parameters on the propulsion of the PCC actuator are investigated by a mathematical model, finite element analysis, and experiments to further elucidate its energy storage and release mechanism. Moreover, the PCC actuator is applied to realize a soft gripper, a prestressed hinge, and a wireless jellyfish-like robot, whose performances are verified by experiments. Results demonstrate the high flexibility and rapid response of the soft gripper and prestressed hinge. In particular, the gripper is capable of stably gripping objects 40 times its weight for extended periods. In addition, the wireless jellyfish-like robot achieves an upward swimming speed of 58.03 mm/s, which is superior to the existing soft jellyfish-like robots of similar size. Overall, the PCC actuator features a lightweight structure and high energy storage capacity, providing significant potential for innovative applications in soft robotics.

A core soft-robotics challenge for underwater locomotion is reconciling soft actuation's compliance with the control tractability and robustness of rigid structures. We present SpineWave, a biomimetic robotic fish that adopts a compliant design within a hybrid soft-rigid architecture: rigid, additively manufactured vertebrae embed opposing magnets that provide passive magnetic compliance, enabling soft-like undulatory bending and impact tolerance while retaining a pressure-tolerant, analytically tractable backbone. Rather than manual tuning, we optimize a low-parameter central-pattern-generator (CPG) controller via hardware-in-the-loop efficient global optimization (EGO). The EGO-tuned gaits deliver a 38% increase in cruising speed and a 35% reduction in turning radius relative to pre-optimization baselines, and achieve 29% energy savings when exploiting vortex wakes, while maintaining stable body-wave propagation across modular morphologies. To our knowledge, SpineWave is the first fish robot to realize soft-like compliance and field robustness using an entirely rigid, magnetically coupled exoskeleton-endoskeleton. This combination of passive magnetic compliance and data-driven CPG optimization advances soft-robotic locomotion and offers a pressure-tolerant, modular platform for long-duration environmental monitoring and exploration.

In muscle tissues, muscle fibers generate active force, muscle spindles provide passive proprioceptive feedback, and connective tissues tightly bind their movements together, forming a reliable biological system. Inspired by this, we propose a single material fabrication method to monolithically print pneumatic proprioceptive actuators (MPPPAs). By leveraging the multifunctional properties of thermoplastic polyurethane (TPU), including inherent flexibility, fusibility, and translucency, and employing a desktop-level fused deposition modeling printer, airtight chambers and embedded optical waveguides are realized within a continuous printing process. Optimized printing parameters lead to fully densified chambers, resulting in a leakage rate of only 0.85% under 200 kPa and maintaining 462.55 kPa after 10 minutes from an initial 500 kPa. The optical waveguides exhibit robust proprioception, maintaining a stable signal over 5000 bending cycles with less than 0.5% drift. Mechanical tests confirm synchronized deformation and continuous structural integration across the monolithically co-printed actuator-sensor region, enabling MPPPAs to achieve reliable actuation-sensing performance with sensing errors below 1.82%. Demonstrations include precise surface contour measurement with the root mean square error of 0.16 mm and real-time gripping width estimation, validating the method's effectiveness in fabricating compact and stable proprioceptive actuators. This research advances actuation-sensing integration in soft robotics, enabling streamlined fabrication and improved reliability for future intelligent systems.

To test food, drug formulations, and medical devices, extensive research has focused on developing in vitro gastric simulators. Existing simulators range from rigid mechanical systems to flexible polymer-based designs, each with distinct limitations in replicating the stomach's complex biomechanical properties. While soft pneumatic actuators provide a foundation for soft robotics-based systems, achieving biomimetic functionality requires control strategies that address both contraction motility precision and compliant interaction dynamics. In this study, we integrate admittance control with finite-time state-dependent Riccati equation (FT-SDRE) and propose a compliant and robust combined force and displacement control for a soft actuator used in robotic gastric simulator. This approach enables a more biomimetic simulation of smooth muscle in gastrointestinal (GI) system when the actuators contact the contents and can help reduce excessive stress on the soft actuator. A three-phase contact model is proposed to describe the force-deformation behavior of the actuator while interacting with the contents, followed by experimental validation. The novel admittance-controlled FT-SDRE enhances both safety and physiological realism in soft tissue interaction. Experimental validation was conducted using three objects: an irregular-shaped gelatin sample, a regular-shaped gelatin sample (same material, different geometry), and an air-filled latex balloon. Compared with nonadmittance FT-SDRE control, the admittance-controlled FT-SDRE reduced 11.19% to 38.46% average contact force according to different objects. Across all tests, the time spent above a force threshold was reduced by 35-39%, which highlights the potential of the proposed method to improve safety, adaptability, and biomimicry in next-generation in vitro gastric simulation platforms.

Although the mobility of climbing robots has made significant progress, especially the flipping climbing robots which possess strong adaptability to unstructured environments, their movement in complex unstructured constrained environments remains a challenge. This work proposes a flipping continuous wall-climbing robot, which maintains the capabilities of wall climbing, turning, obstacle overcoming, and transitioning between different planes. It can continuously move across unstructured wall surfaces, traverse narrow gaps, and crawl on walls in constrained spaces. The robot is composed of a trunk formed by three segments of continuous joint groups and magnetic adhesion modules at both ends, utilizing an untethered design. We conducted an analysis of the robot's kinematic model and workspace. Experimental results demonstrate that the robot is equipped with multiple basic locomotion abilities, allowing it to execute 360° transitions between surfaces, navigate through apertures measuring 15 cm in diameter (0.37 body length), and move along the side walls of confined spaces that are 11 cm wide (0.27 body length). Additionally, the robot is capable of variable-radius flipping locomotion, supporting an effective payload of 520 g on the wall surface, and facilitating coordinated movement among multiple robots.

Robotic systems' mobility is fundamentally constrained by their power sources and wiring requirements. While electrical actuation systems have achieved autonomy through battery power and wireless control, pneumatic actuators remain tethered to air supply sources. Liquid-to-gas phase change actuators utilizing low-boiling-point liquids offer a potential solution, though they typically require substantial thermal input through heating elements that maintain electrical dependencies. External heat sources, particularly light energy, present an alternative for terrestrial applications. However, despite their optical transparency, silicone-based materials have a high volumetric heat capacity and low thermal conductivity, which limits efficient photothermal energy transfer. Previous attempts to address this issue through the incorporation of graphene or metallic powder have compromised material properties, including reduced transparency and altered elastic moduli. Inspired by the tapetum lucidum structure found in the eyes of nocturnal animals, which enables efficient light utilization in low-light conditions, this study proposes a novel anisotropic bilayer soft actuator incorporating Laser-Induced Graphene (LIG) on the inner surface of the light-irradiated silicone layer. This creates an anisotropic structure with enhanced photothermal conversion capabilities while maintaining the advantageous properties of silicone. Comparative analysis demonstrates that the proposed actuator exhibits significantly higher photo-induced bending efficiency than conventional silicone-based actuators. The response time improved by 54%, decreasing from 142 s for pure silicone to 65 s, with recovery response time showing a 48% improvement. This design maintains the silicone's transparency and flexibility while utilizing LIG, which can be fabricated under ambient conditions, facilitating manufacturing and diverse applications.

Tensegrity-based continuum manipulators (TCMs) are rigid-flexible coupling mechanisms that show great promise for applications in unstructured environments by actively or passively conforming to objects. However, the coupling effects of TCMs require significant effort in resolving the actuation redundancy for performing dexterous manipulation tasks. Inspired by the functions of the elephant trunk, this article proposes a modular TCM composed of preprogrammable bend-twist modules (PBTMs) that employ enhanced segmented actuation. This actuation strategy effectively decouples adjacent segments and separates curvature and directional control, simplifying both mechanical integration and control implementation. By designing a preprogramming template attached to the end module, various twisting motions can be achieved in situ, achieving the multimodal deformation of the PBTM. In this setup, the manipulator is capable of bending or twisting in various planes, enabling the manipulator to better conform with objects of varying shape and pose. Then, we derived a dynamic model in terms of natural coordinates with clustered cable (CTC) elements to predict the configuration of the manipulator. Based on the numerical results, we analyze the effect of the CTCs' rest length on the cable slack phenomenon during the bending motion, as well as the in situ preprogrammed twist motion of the manipulator. Finally, we fabricated a manipulator prototype consisting of two PBTMs and showcased its versatile multimodal deformation in experimental scenarios for object wrapping and obstacle avoidance. The experimental results demonstrate that our proposed modular TCM provides a feasible paradigm, which reduces the control complexity of the continuum manipulator system.

Soft robotics solutions to unmet clinical needs represent an emergent disruptive technology. However, clear guidelines on the selection of sterilization methods that consider the preservation of essential physical and functional characteristics of such materials are presently lacking. We reviewed 76 studies that assessed the morphological, mechanical, and functional impact of sterilization on chemically stable and stimuli-responsive hydrogels and polymers. Gamma irradiation was well-tolerated in both stable and stimuli-responsive polymers and conferred additional beneficial material properties. Steam sterilization was suitable for most hydrogels and stimuli-responsive polymers, whereas ethylene oxide sterilization produced mixed effects in stable polymers.