Soft robotics最新文献

Recently, there has been an increased interest in endowing intelligent behaviors and features in soft robotic systems. As a prerequisite for intelligence, a system must integrate sensing, information processing, and the ability to act in response to external stimuli. This work presents a soft robotic crawler that demonstrates locomotion using electroactive liquid crystal elastomers (LCEs). By integrating independent components such as a photo-responsive LCE switch into a conductive electromechanical processing network based on sequential logic, the robot can sense optical indicators and process this information to change direction autonomously. This study expands the design of the individual mechanical material subsystems and experimentally showcases the autonomous operation of the soft robot. The embedded bistable mechanism stores the present operational state of the robot and enforces directional locomotion by controlling the position of a mechanical hard stop that interfaces with the legs. The robot exemplifies the advanced potential of soft intelligent material systems for complex autonomous behavior, leveraging the unique properties of LCEs and a mechanical-electrical network for information processing without the need for traditional electronic controllers.

Robotic links play a vital role in transmitting force and torque, ensuring precise robotic movements. Traditional rigid links, typically made from metals, pose a risk of injury in human-robot interactions or damage to other objects due to their noncompliant and stiff nature and have limited adaptability across various tasks. Variable stiffness robotic links (VSRLs) using hydraulically amplified self-healing electrostatic (HASEL) actuators offer a solution, enhancing safety and adaptability while maintaining precision. This study introduces an electrohydraulic jammed VSRL utilizing a strip-shaped HASEL actuator, which stiffens upon application of high-voltage, pressurizing dielectric liquid encased in a dielectric bladder to achieve stiffness variations up to 8.3 times. The VSRL, optimized by adjusting liquid volume and sealing patterns, is lightweight and compact and eliminates the need for bulky pumps and motors. It also functions as a capacitor, enabling a self-sensing strategy to detect deformation. Experimental results demonstrate significant stiffness variability and effective load-bearing capabilities. Multi-VSRL assemblies further enhance stiffness for practical applications, including collaborative robotic links and wearable robots for joint support. A unique drone application showcases the VSRL's potential for energy-efficient aerial operations. The proposed VSRL represents a promising advancement in robotic technology, offering improved safety, adaptability, and functionality for diverse real-world applications.

Achieving strong adaptability and high-load capacity for small-scale soft robots remains a challenge in current robotics engineering. In this study, inspired by a snail movement, we developed a soft crawling robot capable of controllable locomotion and carrying a load of 204 g-7.7 times its own weight-using just one single motor for robot control. The robot measures 7.6 cm in length, 3 cm in width, and 2.5 cm in height, with a total weight of 26.5 g. The anisotropic friction mechanism on the robot's bottom, comprising a soft origami-based pad and asymmetrical sawtooth structure, enables its strong adhesion to stick to and simultaneously crawl (transitional adhesion) on many surfaces. This design allows the robot to move at speeds up to 3 mm/s and climb a slope of 35° inclinations, also making it suitable for various uneven terrains. Additionally, the robot has enhanced cross-environmental capabilities due to its ability to glide on the water. This research advances the development of relatively simple small-scale single-actuator robots, providing insights into their potential for flexible movement, high-load capacity, and potential swarming behavior.

Existing climbing robots achieve stable movements on limited surface types. However, adapting a single robot design to various surface shapes remains a substantial challenge. Based on the van der Waals (vdW) force-mediated adhesion mechanism of a gecko foot and negative pressure from octopus suckers, this study introduces a biomimetic integration strategy for designing and fabricating a pneumatically actuated switchable adhesion system (SAS). The SAS includes an adhesive material responsible for generating vdW forces and a suction cup with a membrane structure that enables a vacuum suction force. Owing to nonlinear superposition effects, this SAS exhibited a 56.4% higher adhesion force than the algebraic superposition of the vdW and vacuum suction forces. Moreover, the SAS offers a quick switch between adhesion and detachment through pneumatic modulation, achieving a synergistic balance between adaptability, robustness, and load-bearing efficiency. Equipped with this SAS, we developed a pneumo-electrically actuated quadruped-climbing robot that can climb planes with different tilt angles and surfaces with different curvatures.

In daily living, people grasp an object through the steps of "pre-shaping" and "enclosing," with the thumb playing a crucial role with its multiple degrees of freedom. When assisting individuals with hand impairments using soft wearable robots, it is important to simplify the robot by reducing the number of actuators and to provide different grasping strategies based on various objects being handled. In this article, we propose a tendon-driven soft wearable hand robot, Exo-Glove Poly III, that uses a single actuator for assisting two types of grasping strategies for people with hand impairment. To move the thumb and other fingers with a single actuator, we developed a slack-based sequential mechanism that allows movements to occur at different timings by varying the initial slack lengths of each tendon. Based on our observations of grasping strategies and the proposed novel actuation system, a slack-based sequential actuator (318 g, including electronic circuits) was designed and integrated with the glove (90 g) using a commercial armband to make the system portable. The robotic system was evaluated by a healthy subject, showing how the thumb moves by the tendon routings and how the mechanism works for each grasping strategy.

Respiratory assistance is commonly used to treat respiratory system diseases or support postoperative recovery, playing a crucial role in patient rehabilitation. However, existing respiratory assistance devices rely on rigid systems, which may pose risks to the human body. To address this, we propose a novel soft abdominal compression robot for respiratory assistance (SACR-RA), which offers personalized and adaptive support. This novel ability is achieved by dynamically adjusting the pressure applied to the abdomen in real-time on the basis of the user's respiratory characteristics. First, we developed a pressure-deformation model for soft pneumatic actuators and confirmed its accuracy through experiments. Next, we developed a human respiratory model that links respiratory assistance levels to lung conditions, enabling flexible adjustment of control strategies on the basis of the user's condition. Accordingly, we designed respiratory pattern control and respiratory intensity control strategies to ensure adaptable support for the user's respiratory needs. Finally, we validated the effectiveness of SACR-RA through respiratory flow and electromyography experiments. The results demonstrated that SACR-RA significantly improves the exchange of air between the user and the environment and reduces the burden on respiratory muscles.

Throughout the development of soft robots, shape memory alloy (SMA) actuators have received considerable attention due to their inherent advantages, such as high power-to-weight ratio, low driving voltage, and high response speed. This study presents a lattice-reinforced SMA actuator with improved response speed and increased deformation range. The SMA wires are used to drive the actuator to achieve bending, while the high elastic wire's elasticity is used to achieve recovery. The actuator is cast into a lattice structure with five connection nodes, named Lattice-N5. Lattice-N5's fast response properties are validated through finite element analysis and experiments. Compared with the actuator without lattice structure (nonlattice), lattice-N5's bending deformation increases by up to 390.59% and 204.4% under optimal (voltage of 20 V, duty ratio of 30%, and frequency of 4 Hz) and practical (voltage of 20 V, duty ratio of 20% and frequency of 1 Hz) conditions, respectively, while reaching a stable state more rapidly under a periodic actuation. Therefore, the lattice-reinforced actuator exhibits robust actuation capabilities and improved response frequencies and thus can be employed in a biomimetic jellyfish robot for underwater monitoring and detection by combining a flexible pressure sensor. Moreover, the jellyfish robot with Lattice-N5 actuators exhibits a speed improvement of 111% under the optimal condition (duty ratio of 20% and frequency of 4 Hz) and 55% under the practical condition (voltage of 20 V, duty ratio of 20% and frequency of 1 Hz) compared with the robot with the nonlattice. This study provides a simple and effective design scheme for improving the performance of SMA actuators and prompting the development of underwater soft robots.

Numerous studies have attempted to develop medical devices using vine robots due to their potential for frictionless locomotion and adaptability in confined environments. However, for applications in colonoscopy, challenges such as high stiffness, limited steering capabilities, difficulties in integrating tethered sensors, and issues related to safe retraction have hindered their practical application. This article addresses these challenges and presents a comprehensive solution that simultaneously resolves these issues while preserving the intrinsic features of vine robots. We propose a novel soft robotic endoscope that leverages an optimized eversion mechanism to maintain low stiffness and ensure compliance with the natural curvature of the colon, minimizing bowel distension. To enable real-time imaging, we introduce a passive tethered camera stabilization system that secures the camera at the distal tip with minimal internal tension. Additionally, the device integrates active steering capabilities using fabric pneumatic artificial muscles, allowing for precise two-degree-of-freedom steering to navigate through complex pathways. A non-sealed, self-retractable mechanism ensures safe and reliable retraction by preventing buckling while maintaining the robot's compliance, even with an embedded tethered sensor inside the inner channel. Comprehensive characterization of key parameters, such as vine diameter and retraction channel geometry, further enhances the system's performance in endoscopic applications. The effectiveness of the proposed endoscope was validated through extensive testing in endoscopic phantom models and in vivo trials, demonstrating significant reductions in insertion forces and colon deformation compared with conventional endoscopes. In phantom studies, the device demonstrated an 80% reduction in mesentery extension compared with a conventional flexible endoscope. In vivo, the soft growing endoscope (SGE) reached the ileocecal valve within 2 min while maintaining real-time imaging, internal channel integrity, and buckling-free retraction. By overcoming key challenges in adapting vine robots for endoscopy, this SGE offers a minimally invasive, safer, and more effective solution for colonoscopy, enhancing patient comfort and procedural efficiency while reducing physical strain on physicians.

Sim-to-real transfer remains a significant challenge in soft robotics due to the unpredictability introduced by common manufacturing processes such as 3D printing and molding. These processes often result in deviations from simulated designs, requiring multiple prototypes before achieving a functional system. In this study, we propose a novel methodology to address these limitations by combining advanced rapid prototyping techniques and an efficient optimization strategy. First, we employ rapid prototyping methods typically used for rigid structures, leveraging their precision to fabricate compliant components with reduced manufacturing errors. Second, our optimization framework minimizes the need for extensive prototyping, significantly reducing the iterative design process. The methodology enables the identification of stiffness parameters that are more practical and achievable within current manufacturing capabilities. The proposed approach demonstrates a substantial improvement in the efficiency of prototype development while maintaining the desired performance characteristics. This work represents a step forward in bridging the sim-to-real gap in soft robotics, paving the way toward a faster and more reliable deployment of soft robotic systems.

Hydraulically amplified self-healing electrostatic (HASEL) actuators are known for their muscle-like activation, rapid operation, and direct electrical control, making them highly versatile for use in soft robotics. While current methods for enhancing HASEL actuator performance largely emphasize material innovation, our approach offers an additional architectural strategy. In this study, we introduce a novel hydraulically amplified rigidity-adaptive electrostatic (HARIE) actuator designed to significantly enhance HASEL actuator performance while maintaining controllability by elucidating the underlying issues of the pull-in instability. Our experimental results indicate that the HARIE actuator achieves a significant improvement, with over a 200% increase in angular output and consistently strong torque compared with HASEL actuators with flexible electrodes. Notably, the maximum step of the HARIE actuator is 21.8°/kV, approximately one third of that of the HASEL actuator with rigid electrodes (62.3°/kV), suggesting smoother motion control. The HARIE actuator's effectiveness is further demonstrated in practical applications; it successfully grasps an orange weighing 15.2 g and a delicate dandelion. Additionally, the actuator's precise targeting capability is evidenced by its ability to manipulate a laser to induce heat accumulation, leading to the balloon's breakdown, thereby showcasing its high level of controllability. The rigidity-adaptive method mitigates the negative impacts of suboptimal materials and demonstrates the potential for significant enhancement when combined with superior materials.