Lulu Yang

Bio: Lulu Yang is an academic researcher from Hefei University of Technology. The author has contributed to research in topics: Actuator & Bilayer. The author has an hindex of 7, co-authored 17 publications receiving 283 citations.

Electrically and Sunlight-Driven Actuator with Versatile Biomimetic Motions Based on Rolled Carbon Nanotube Bilayer Composite

Abstract: Designing multistimuli responsive soft actuators which can mimic advanced and sophisticated biological movements through simple configuration is highly demanded for the biomimetic robotics application. Here, inspired by the human's flick finger behavior which can release large force output, a soft jumping robot mimicking the gymnast's somersault is designed based on the rolled carbon nanotube/polymer bilayer composite actuator. This new type of rolled bilayer actuator with tubular shape is fabricated and shows electrically and sunlight-induced actuation with remarkable performances including ultralarge deformation from tubular to flat (angel change >200° or curvature >2 cm−1), fast response (<5 s), and low actuation voltage (≤10 V). Besides jumping, the uniquely reversible rolling–unrolling actuation can lead to other smart soft robots with versatile complex biomimetic motions, including light-induced tumbler with cyclic wobbling, electrically/light-induced crawling-type walking robots and grippers, electrically induced mouth movement, and ambient-sunlight-induced blooming of a biomimetic flower. These results open the way for using one simple type of actuator structure for the construction of various soft robots and devices toward practical biomimetic applications.

Self-Locomotive Soft Actuator Based on Asymmetric Microstructural Ti3C2Tx MXene Film Driven by Natural Sunlight Fluctuation.

Abstract: Soft actuators and microrobots that can move spontaneously and continuously without artificial energy supply and intervention have great potential in industrial, environmental, and military applications, but still remain a challenge. Here, a bioinspired MXene-based bimorph actuator with an asymmetric layered microstructure is reported, which can harness natural sunlight to achieve directional self-locomotion. We fabricate a freestanding MXene film with an increased and asymmetric layered microstructure through the graft of coupling agents into the MXene nanosheets. Owing to the excellent photothermal effect of MXene nanosheets, increased interlayer spacing favoring intercalation/deintercalation of water molecules and its caused reversible volume change, and the asymmetric microstructure, this film exhibits light-driven deformation with a macroscopic and fast response. Based on it, a soft bimorph actuator with ultrahigh response to solar energy is fabricated, showing natural sunlight-driven actuation with ultralarge amplitude and fast response (346° in 1 s). By utilizing continuous bending deformation of the bimorph actuator in response to the change of natural sunlight intensity and biomimetic design of an inchworm to rectify the repeated bending deformation, an inchwormlike soft robot is constructed, achieving directional self-locomotion without any artificial energy and control. Moreover, soft arms for lifting objects driven by natural sunlight and wearable smart ornaments that are combined with clothing and produce three-dimensional deformation under natural sunlight are also developed. These results provide a strategy for developing natural sunlight-driven soft actuators and reveal great application prospects of this photoactuator in sunlight-driven soft biomimetic robots, intelligent solar-energy-driven devices in space, and wearable clothing.

A powerful dual-responsive soft actuator and photo-to-electric generator based on graphene micro-gasbags for bioinspired applications.

Abstract: Soft actuators with large deformation and high output force in response to multi-stimuli are highly demanded for the development of biomimetic applications. Here, a bilayer actuator composed of spongy graphene with internal gasbag microstructures and the commercial polyimide adhesive tape is fabricated by a simple and fast method. This actuator produces large deformation, high output force, and dual-stimuli response, owing to the deformation of graphene micro-gasbags coupled with the thermal expansion of polyimide, and the electrothermal and photothermal properties of graphene. Experiments show that upon low voltage (16 V) stimulation the fabricated actuator with a length of 30 mm could generate a bending curvature of 0.55 cm−1 in 5 s, and can simultaneously produce high output force and lift an object 20 times heavier than its own weight. Moreover, a curvature of 0.45 cm−1 can be achieved for the actuator upon light irradiation for 10 s. Based on this bilayer actuator, diversely biomimetic motions including kicking a ball, grabbing a vegetable leaf, human hand movement, and creeping motion are realized, revealing its potential application in soft robotics, artificial muscles, wearable electronics, and biomedical devices. Besides the mechanical deformation output, a photo-to-electric generator is also assembled by associating this actuator with commonly triboelectric materials, further enriching the application range of soft actuators.

Soft Robotic Grippers.

Abstract: Advances in soft robotics, materials science, and stretchable electronics have enabled rapid progress in soft grippers. Here, a critical overview of soft robotic grippers is presented, covering different material sets, physical principles, and device architectures. Soft gripping can be categorized into three technologies, enabling grasping by: a) actuation, b) controlled stiffness, and c) controlled adhesion. A comprehensive review of each type is presented. Compared to rigid grippers, end-effectors fabricated from flexible and soft components can often grasp or manipulate a larger variety of objects. Such grippers are an example of morphological computation, where control complexity is greatly reduced by material softness and mechanical compliance. Advanced materials and soft components, in particular silicone elastomers, shape memory materials, and active polymers and gels, are increasingly investigated for the design of lighter, simpler, and more universal grippers, using the inherent functionality of the materials. Embedding stretchable distributed sensors in or on soft grippers greatly enhances the ways in which the grippers interact with objects. Challenges for soft grippers include miniaturization, robustness, speed, integration of sensing, and control. Improved materials, processing methods, and sensing play an important role in future research.

Significance of Nanomaterials in Wearables: A Review on Wearable Actuators and Sensors.

Abstract: Together with the evolution of digital health care, the wearable electronics field has evolved rapidly during the past few years and is expected to be expanded even further within the first few years of the next decade. As the next stage of wearables is predicted to move toward integrated wearables, nanomaterials and nanocomposites are in the spotlight of the search for novel concepts for integration. In addition, the conversion of current devices and attachment-based wearables into integrated technology may involve a significant size reduction while retaining their functional capabilities. Nanomaterial-based wearable sensors have already marked their presence with a significant distinction while nanomaterial-based wearable actuators are still at their embryonic stage. This review looks into the contribution of nanomaterials and nanocomposites to wearable technology with a focus on wearable sensors and actuators.

Smart Textile-Integrated Microelectronic Systems for Wearable Applications

Abstract: The programmable nature of smart textiles makes them an indispensable part of an emerging new technology field. Smart textile-integrated microelectronic systems (STIMES), which combine microelectronics and technology such as artificial intelligence and augmented or virtual reality, have been intensively explored. A vast range of research activities have been reported. Many promising applications in healthcare, the internet of things (IoT), smart city management, robotics, etc., have been demonstrated around the world. A timely overview and comprehensive review of progress of this field in the last five years are provided. Several main aspects are covered: functional materials, major fabrication processes of smart textile components, functional devices, system architectures and heterogeneous integration, wearable applications in human and nonhuman-related areas, and the safety and security of STIMES. The major types of textile-integrated nonconventional functional devices are discussed in detail: sensors, actuators, displays, antennas, energy harvesters and their hybrids, batteries and supercapacitors, circuit boards, and memory devices.

Carbon-Based Photothermal Actuators

Abstract: Actuators that can convert environmental stimuli into mechanical work are widely used in intelligent systems, robots, and micromechanics. To produce robust and sensitive actuators of different scales, efforts are devoted to developing effective actuating schemes and functional materials for actuator design. Carbon-based nanomaterials have emerged as preferred candidates for different actuating systems because of their low cost, ease of processing, mechanical strength, and excellent physical/chemical properties. Especially, due to their excellent photothermal activity, which includes both optical absorption and thermal conductivities, carbon-based materials have shown great potential for use in photothermal actuators. Herein, the recent advances in photothermal actuators based on various carbon allotropes, including graphite, carbon nanotubes, amorphous carbon, graphene and its derivatives, are reviewed. Different photothermal actuating schemes, including photothermal effect–induced expansion, desorption, phase change, surface tension gradient creation, and actuation under magnetic levitation, are summarized, and the light-to-heat and heat-towork conversion mechanisms are discussed. Carbon-based photothermal actuators that feature high light-to-work conversion efficiency, mechanical robustness, and noncontact manipulation hold great promise for future autonomous systems.

Soft Actuators for Soft Robotic Applications: A Review

Abstract: The authors acknowledge generous support of the King Abdullah University of Science and Technology (KAUST). The authors acknowledge Dr. Joanna M. Nassar, Dr. Galo A. Torres, Dr. Mohamed T. Ghoneim, Andres A. Aguirre-Pablo, Davide Priante, Dr. Jhonathan P. Rojas, Sigurdur T. Thoroddsen, and Prof. Boon S. Ooi who contributed to the “pause-embed-resume” data. The authors thank Kelly Rader for proof reading this manuscript.