Actuator plays a significant role in soft robotics.This paper proposed an ultralong stretchable soft actuator(US2A)with a variable and sizeable maximum elongation.The US2A is composed of a silicone rubber tube and a b...Actuator plays a significant role in soft robotics.This paper proposed an ultralong stretchable soft actuator(US2A)with a variable and sizeable maximum elongation.The US2A is composed of a silicone rubber tube and a bellows woven sleeve.The maximal extension can be conveniently regulated by just adjusting the wrinkles’initial angle of the bellows woven sleeve.The kinematics of US2A could be obtained by geometrically analyzing the structure of the bellows woven sleeve when the silicone rubber tube is inflated.Based on the principle of virtual work,the actuating models have been established:the pressure-elongation model and the pressure-force model.These models reflect the influence of the silicone tube’s shell thickness and material properties on the pneumatic muscle’s performance,which facilitates the optimal design of US2A for various working conditions.The experimental results showed that the maximum elongation of the US2A prototype is 257%,and the effective elongation could be variably regulated in the range of 0 and 257%.The proposed models were also verified by pressure-elongation and pressure-force experiments,with an average error of 5%and 2.5%,respectively.Finally,based on the US2A,we designed a pneumatic rehabilitation glove,soft arm robot,and rigid-soft coupling continuous robot,which further verified the feasibility of US2A as a soft driving component.展开更多
In nature,many living organisms exhibiting unique structural coloration and soft-bodied actuation have inspired scientists to develop advanced structural colored soft actuators toward biomimetic soft robots.However,it...In nature,many living organisms exhibiting unique structural coloration and soft-bodied actuation have inspired scientists to develop advanced structural colored soft actuators toward biomimetic soft robots.However,it is challenging to simultaneously biomimic the angle-independent structural color and shape-morphing capabilities found in the plum-throated cotinga flying bird.Herein,we report biomimetic MXene-based soft actuators with angle-independent structural color that are fabricated through controlled self-assembly of colloidal SiO_(2) nanoparticles onto highly aligned MXene films followed by vacuum-assisted infiltration of polyvinylidene fluoride into the interstices.The resulting soft actuators are found to exhibit brilliant,angle-independent structural color,as well as ultrafast actuation and recovery speeds(a maximum curvature of 0.52 mm−1 can be achieved within 1.16 s,and a recovery time of~0.24 s)in response to acetone vapor.As proof-of-concept illustrations,structural colored soft actuators are applied to demonstrate a blue gripper-like bird’s claw that can capture the target,artificial green tendrils that can twine around tree branches,and an artificial multicolored butterfly that can flutter its wings upon cyclic exposure to acetone vapor.The strategy is expected to offer new insights into the development of biomimetic multifunctional soft actuators for somatosensory soft robotics and next-generation intelligent machines.展开更多
A new type of soft actuator material-ionic liquid gel (ILG), which consists of HEMA, BMIMBF4, and TiO2, can be transformed into gel state under the irradiation of ultraviolet (UV) light. In this paper, Mooney-Rivl...A new type of soft actuator material-ionic liquid gel (ILG), which consists of HEMA, BMIMBF4, and TiO2, can be transformed into gel state under the irradiation of ultraviolet (UV) light. In this paper, Mooney-Rivlin hyperelastic model of finite element method is proposed for the first time to study the properties of the ILG. It has been proved that the content of TiO2 has a great influence on the properties of the gel, and Young's modulus of the gel increases with the increase of its content, despite of reduced tensile deformation. The results in this work show that when the TiO2 content is 1.0 wt%, a large tensile deformation and a strong Young's modulus can be obtained to be 325% and 7.8 kPa, respectively. The material parameters of ILG with TiO2 content values of 0.2 wt%, 0.5 wt%, 1.0 wt%, and 1.5 wt% are obtained, respectively, through uniaxial tensile tests, including C10, C01, C20, C11, C02, C30, C21, C12, and C03 elements. In this paper, the large-scaled general finite element software ANSYS is used to simulate and analyze the ILG, which is based on SOLID186 element and nonlinear hyperelastic Mooney-Rivlin model. The finite element simulation analysis based stress-strain curves are almost consistent with the experimental stress-strain curves, and hence the finite element analysis of ILG is feasible and credible. This work presents a new direction for studying the performance of soft actuator for the ILG, and also contributes to the design of soft robot actuator.展开更多
Remote controlled soft actuators have attracted ever-increasing interest in industrial,medical,robotics,and engineering fields.Soft actuators are charming than normal tools in executing dedicate tasks due to small vol...Remote controlled soft actuators have attracted ever-increasing interest in industrial,medical,robotics,and engineering fields.Soft actuators are charming than normal tools in executing dedicate tasks due to small volume and flexible body they have.However,it remains a challenge to design soft actuator that can adapt to multi-environments under remote stimuli with promising nano materials.Herein,we have developed a kind of near-infrared laser driven soft actuators with multi locomotive modes based on WSe2 and graphene nanosheets heterojunction.Different locomotion modes are driven by photothermal effect induced deformation to adapt to different working conditions.Moreover,the specially designed gripper driven by pulsed laser can lift a heavy load which is four times of its weight.This work broadens the choice of advanced nanomaterials for photothermal conversion of soft actuators.It is promising to realize applications including photothermal therapy and complex environment detection through the combination of the intelligent robot design and optical fiber system.展开更多
Liquid crystal elastomers are active materials that combine the anisotropic properties of liquid crystals with the elasticity of polymer networks.The LCEs exhibit remarkable reversible contraction and elongation capab...Liquid crystal elastomers are active materials that combine the anisotropic properties of liquid crystals with the elasticity of polymer networks.The LCEs exhibit remarkable reversible contraction and elongation capabilities in response to external stimuli,rendering them highly promising for diverse applications,such as soft robotics,haptic devices,shape morphing structures,etc,However,the predominant reliance on heating as the driving stimulus for LCEs has limited their practical applications.This drawback can be effectively addressed by incorporating fllers,which can generate heat under various stimuli.The recent progress in LCE composites has significantly expanded the application potential of LCEs.In this minireview,we present the design strategies for soft actuators with LCE composites,followed by a detailed exploration of photothermal and electrothermal LCE.composites as prominent examples.Furthermore,we provide an outlook on the challenges and opportunities in the feld of LCE composites.展开更多
As mechanical devices for moving or controlling mechanisms or systems,actuators have attracted increasing attention in various fields.Compared to traditional actuators with rigid structures,soft actuators made up of s...As mechanical devices for moving or controlling mechanisms or systems,actuators have attracted increasing attention in various fields.Compared to traditional actuators with rigid structures,soft actuators made up of stimulus-responsive soft materials are more adaptable to complex working conditions due to soft bodies and diverse control styles.Different from plate-shaped soft actuators,which have the limited deformations between two dimensional(2D)and 3D-configurations such as bending and twisting,fiber-shaped soft actuators(FSAs)own intriguing deformation modes to satisfy diverse practical applications.In this mini review,the recent progress on the controlled fabrication of the FSAs is presented.The advantages and disadvantages of each fabrication method are also demonstrated.Subsequently,the as-developed actuation mechanisms of the FSAs are displayed.Additionally,typical examples of the related applications of the FSAs in different fields have been discussed.Finally,an outlook on the development tendency of the FSAs is put forward as well.展开更多
Small-scale electromagnetic soft actuators are characterized by a fast response and simplecontrol,holding prospects in the field of soft and miniaturized robotics.The use of liquid metal(LM)to replace a rigid conducto...Small-scale electromagnetic soft actuators are characterized by a fast response and simplecontrol,holding prospects in the field of soft and miniaturized robotics.The use of liquid metal(LM)to replace a rigid conductor inside soft actuators can reduce the rigidity and enhance the actuation performance and robustness.Despite research efforts,challenges persist in the flexible fabrication of LM soft actuators and in the improvement of actuation performance.To address these challenges,we developed a fast and robust electromagnetic soft microplate actuator based on a laser-induced selective adhesion transfer method.Equipped with unprecedentedly thin LM circuit and customized low Young’s modulus silicone rubber(1.03 kPa),our actuator exhibits an excellent deformation angle(265.25?)and actuation bending angular velocity(284.66 rad·s^(-1)).Furthermore,multiple actuators have been combined to build an artificial gripper with a wide range of functionalities.Our actuator presents new possibilities for designing small-scaleartificial machines and supports advancements in ultrafast soft and miniaturized robotics.展开更多
Laser-assisted process can enable facile,mask-free,large-area,inexpensive,customizable,and miniaturized patterning of laser-induced porous graphene(LIG)on versatile carbonaceous substrates(e.g.,polymers,wood,food,text...Laser-assisted process can enable facile,mask-free,large-area,inexpensive,customizable,and miniaturized patterning of laser-induced porous graphene(LIG)on versatile carbonaceous substrates(e.g.,polymers,wood,food,textiles)in a programmed manner at ambient conditions.Together with high tailorability of its porosity,morphology,composition,and electrical conductivity,LIG can find wide applications in emerging bioelectronics(e.g.,biophysical and biochemical sensing)and soft robots(e.g.,soft actuators).In this review paper,we first introduce the methods to make LIG on various carbonaceous substrates and then discuss its electrical,mechanical,and antibacterial properties and biocompatibility that are critical for applications in bioelectronics and soft robots.Next,we overview the recent studies of LIG-based biophysical(e.g.,strain,pressure,temperature,hydration,humidity,electrophysiological)sensors and biochemical(e.g.,gases,electrolytes,metabolites,pathogens,nucleic acids,immunology)sensors.The applications of LIG in flexible energy generators and photodetectors are also introduced.In addition,LIG-enabled soft actuators that can respond to chemicals,electricity,and light stimulus are overviewed.Finally,we briefly discuss the future challenges and opportunities of LIG fabrications and applications.展开更多
Soft robots and actuators are emerging devices providing more capabilities in the field of robotics.More flexibility and compliance attributing to soft functional materials used in the fabrication of these devices mak...Soft robots and actuators are emerging devices providing more capabilities in the field of robotics.More flexibility and compliance attributing to soft functional materials used in the fabrication of these devices make them ideal for delivering delicate tasks in fragile environments,such as food and biomedical sectors.Yet,the intuitive nonlinearity of soft functional materials and their anisotropic actuation in compliant mechanisms constitute an existent challenge in improving their performance.Topology optimization(TO)along with four-dimensional(4D)printing is a powerful digital tool that can be used to obtain optimal internal architectures for the efficient performance of porous soft actuators.This paper employs TO analysis for achieving high bending deflection of a 3D printed polyelectrolyte actuator,which shows bending deformations in response to electrical stimuli in an electrolyte solution.The performance of the actuator is studied in terms of maximum bending and actuation rate compared with a solid,uniformly 3D printed and topology-optimized actuator.The experimental results proved the effectiveness of TO on achieving higher bending deformation and actuation rate against a uniformly 3D printed actuator.展开更多
The multi-cavity soft actuator is assembled from single-cavity soft actuator through a reasonable geometric distribution.It has the characteristic that the pneumatic soft actuator is driven by its own deformation and ...The multi-cavity soft actuator is assembled from single-cavity soft actuator through a reasonable geometric distribution.It has the characteristic that the pneumatic soft actuator is driven by its own deformation and has more degrees of freedom.Pneumatic soft actuator is widely used as an emerging discipline and its strong compliance has been greatly developed and applied.However,as the most application potential type of soft actuators,there is still a lack of simple and effective deformation prediction methods for studying the spatial deformation of multi-cavity soft actuators.To solve this problem,a vector equation method is proposed based on the analysis of the principle of the space deformation of the two-cavity,three-cavity and four-cavity soft actuators.Furthermore,a nonlinear mathematical model of the air pressure,space position and deformation trajectory of the soft actuator end is established by combining the vector equation method.Finally,the three-channel soft actuator is verified through experiments.The results show that the mathematical model can better predict the space deformation trajectory of the soft actuator,which provides a new research method for studying the space deformation of the multi-channel soft actuator.展开更多
Dyskinesia of the upper limbs caused by stroke,sports injury,or trafc accidents limits the ability to perform the activities of daily living.Besides the necessary medical treatment,correct and scientifc rehabilitation...Dyskinesia of the upper limbs caused by stroke,sports injury,or trafc accidents limits the ability to perform the activities of daily living.Besides the necessary medical treatment,correct and scientifc rehabilitation training for the injured joint is an important auxiliary means during the treatment of the efected upper limb.Conventional upperlimb rehabilitation robots have some disadvantages,such as a complex structure,poor compliance,high cost,and poor portability.In this study,a novel soft wearable upper limb rehabilitation robot(SWULRR)with reinforced soft pneumatic actuators(RSPAs)that can withstand high pressure and featuring excellent loading characteristics was developed.Driven by RSPAs,this portable SWULRR can perform rehabilitation training of the wrist and elbow joints.In this study,the kinematics of an SWULRR were analyzed,and the force and motion characteristics of RSPA were studied experimentally.The results provide a reference for the development and application of wearable upper limb rehabilitation robots.An experimental study on the rotation angle of the wrist and the pressure of the RSPA was conducted to test the efect of the rehabilitation training and verify the rationality of the theoretical model.The process of wrist rehabilitation training was tested and evaluated,indicating that SWULRR with RSPAs will enhance the fexibility,comfort,and safety of rehabilitation training.This work is expected to promote the development of wearable upper-limb rehabilitation robots based on modular reinforced soft pneumatic actuators.展开更多
The soft robotics display huge advantages over their rigid counterparts when interacting with living organisms and fragile objects.As one of the most efficient actuators toward soft robotics,the soft pneumatic actuato...The soft robotics display huge advantages over their rigid counterparts when interacting with living organisms and fragile objects.As one of the most efficient actuators toward soft robotics,the soft pneumatic actuator(SPA)can produce large,complex responses with utilizing pressure as the only input source.In this work,a new approach that combines digital light processing(DLP)and injection-assisted post-curing is proposed to create SPAs that can realize different functionalities.To enable this,we develop a new class of photo-cross linked elastomers with tunable mechanical properties,good stretchability,and rapid curing speed.By carefully designing the geometry of the cavities embedded in the actuators,the resulting actuators can realize contracting,expanding,flapping,and twisting motions.In addition,we successfully fabricate a soft self-sensing bending actuator by injecting conductive liquids into the three-dimensional(3D)printed actuator,demonstrating that the present method has the potential to be used to manufacture intelligent soft robotic systems.展开更多
The human wrist, a complex articulation of skeletal muscles and two-carpal rows, substantially contributes to improvements in maneuverability by agilely performing three-degree-of-freedom(3-DOF) orienting tasks and re...The human wrist, a complex articulation of skeletal muscles and two-carpal rows, substantially contributes to improvements in maneuverability by agilely performing three-degree-of-freedom(3-DOF) orienting tasks and regulating stiffness according to variations in interaction forces. However, few soft robotic wrists simultaneously demonstrate dexterous 3-DOF motion and variable stiffness;in addition, they do not fully consider a soft-rigid hybrid structure of integrated muscles and two carpal rows.In this study, we developed a soft-rigid hybrid structure to design a biomimetic soft robotic wrist(BSRW) that is capable of rotating in the x and y directions, twisting around the z-axis, and possessing stiffness-tunable capacity. To actuate the BSRW, a lightweight soft-ring-reinforced bellows-type pneumatic actuator(SRBPA) with large axial, linear deformation(η_(lcmax)=70.6%,η_(lemax)=54.3%) and small radial expansion(η_(demax)=3.7%) is designed to mimic the motion of skeletal muscles. To represent the function of two-carpal rows, a compact particle-jamming joint(PJJ) that combines particles with a membrane-covered ballsocket mechanism is developed to achieve various 3-DOF motions and high axial load-carrying capacity(>60 N). By varying the jamming pressure, the stiffness of the PJJ can be adjusted. Finally, a centrally positioned PJJ and six independently actuated SRBPAs, which are in an inclined and antagonistic arrangement, are sandwiched between two rigid plates to form a flexible,stable, and compact BSRW. Such a structure enables the BSRW to have a dexterous 3-DOF motion, high load-carrying ability,and stiffness tunability. Experimental analysis verify 3-DOF motion of BSRW, producing force of 29.6 N and 36 N and torque of2.2 Nm in corresponding rotations. Moreover, the range of rotational angle and stiffness-tuning properties of BSRW are studied by applying jamming pressure to the PJJ. Finally, a system combining a BSRW and a soft enclosing gripper is proposed to demonstrate outstanding manipulation capability in potential applications.展开更多
Real-time proprioception presents a significant challenge for soft robots due to their infinite degrees of freedom and intrinsic compliance.Previous studies mostly focused on specific sensors and actuators.There is st...Real-time proprioception presents a significant challenge for soft robots due to their infinite degrees of freedom and intrinsic compliance.Previous studies mostly focused on specific sensors and actuators.There is still a lack of generalizable technologies for integrating soft sensing elements into soft actuators and mapping sensor signals to proprioception parameters.To tackle this problem,we employed multi-material 3D printing technology to fabricate sensorized soft-bending actuators(SBAs)using plain and conductive thermoplastic polyurethane(TPU)filaments.We designed various geometric shapes for the sensors and investigated their strain-resistive performance during deformation.To address the nonlinear time-variant behavior of the sensors during dynamic modeling,we adopted a data-driven approach using different deep neural networks to learn the relationship between sensor signals and system states.A series of experiments in various actuation scenarios were conducted,and the results demonstrated the effectiveness of this approach.The sensing and shape prediction steps can run in real-time at a frequency of50 Hz on a consumer-level computer.Additionally,a method is proposed to enhance the robustness of the learning models using data augmentation to handle unexpected sensor failures.All the methods are efficient,not only for in-plane 2D shape estimation but also for out-of-plane 3D shape estimation.The aim of this study is to introduce a methodology for the proprioception of soft pneumatic actuators,including manufacturing and sensing modeling,that can be generalized to other soft robots.展开更多
Soft robotics is a breakthrough technology to support human-robot interactions.The soft structure of a soft robot can increase safety during human and robot interactions.One of the promising soft actuators for soft ro...Soft robotics is a breakthrough technology to support human-robot interactions.The soft structure of a soft robot can increase safety during human and robot interactions.One of the promising soft actuators for soft robotics is dielectric elastomer actuators(DEAs).DEAs can operate silently and have an excellent energy density.The simple structure of DEAs leads to the easy fabrication of soft actuators.The simplicity combined with silent operation and high energy density make DEAs interesting for soft robotics researchers.DEAs actuation follows the Maxwell-pressure principle.The pressure produced in the DEAs actuation depends much on the voltage applied.Common DEAs requires high voltage to gain an actuation.Since the power consumption of DEAs is in the milli-Watt range,the current needed to operate the DEAs can be neglected.Several commercially available DC-DC converters can convert the volt range to the kV range.In order to get a voltage in the 2-3 kV range,the reliable DC-DC converter can be pricy for each device.This problem hinders the education of soft actuators,especially for a newcomer laboratory that works in soft electric actuators.This paper introduces an entirely do-it-yourself(DIY)Ultrahigh voltage amplifier(UHV-Amp)for education in soft robotics.UHV-Amp can amplify 12 V to at a maximum of 4 kV DC.As a demonstration,we used this UHV-Amp to test a single layer of powdered-based DEAs.The strategy to build this educational type UHV-Amp was utilizing a Cockcroft-Walton circuit structure to amplify the voltage range to the kV range.In its current state,the UHV-Amp has the potential to achieve approximately 4 kV.We created a simple platform to control the UHV-Amp from a personal computer.In near future,we expect this easy control of the UHV-Amp can contribute to the education of soft electric actuators.展开更多
Designing soft robots that are able to perceive unstructured,dynamic environments and their deformations has been a long-term goal.Previously reported self-sensing soft actuators were mostly constructed via integratin...Designing soft robots that are able to perceive unstructured,dynamic environments and their deformations has been a long-term goal.Previously reported self-sensing soft actuators were mostly constructed via integrating separate actuators and sensors.The actuation performances and the sensing reliability are affected owing to the unmatched materials and weak connections.Realizing a seamless integration of soft actuators and sensors remains a grand challenge.Here,we report a fabrication strategy to endow soft actuators with sensing capability and programmable actuation performances.The foam inside the actuator functions as actuator and sensor simultaneously,effectively addressing the conformability and connection reliability issues that existed in current self-sensing actuators.The actuators are lightweight(a decrease of 58%in weight),powerful(lifting a load of 433 times of its own weight),and versatile(coupling twisting and contraction motions).Furthermore,the actuators are able to detect multiple physical stimuli with high reliability,demonstrating their exteroception and proprioception capability.Two self-sensing soft robotic prototypes,including a bionic bicep and a bionic neck,are constructed to illustrate their multifunctionality.Our study opens up new possibilities for the design of soft actuators and has promising potential in a variety of applications,ranging from human-robot interaction,soft orthotics,to wearable robotics.展开更多
Electrochemical actuators based on conductive polymers are emerging as a strong competitive in the field of soft actuators because of their intrinsically conformable/elastic nature,low cost,low operating voltage and a...Electrochemical actuators based on conductive polymers are emerging as a strong competitive in the field of soft actuators because of their intrinsically conformable/elastic nature,low cost,low operating voltage and air-working ability.Recent development has shown that adding electroactive materials,such as CNT and graphene,can improve their actuation performance.Despite the complex material systems used,their output strains(one of the key factors)are generally lower than 1%,which limited further applications of them in multiple scenarios.Here,we report soft electrochemical actuators based on conductive polymer ionogels by embedding polyaniline particles between the PEDOT:PSS nanosheets.Results show that such a hierarchical structure not only leads to a high conductivity(1250 S/cm)but also improved electrochemical activities.At a low operating voltage of 1 V,the maximum strain of these soft actuators reaches an exceptional value of 1.5%,with a high blocking force of 1.3 mN.Using these high-performance electrochemical actuators,we demonstrate soft grippers for manipulating object and a bionic flower stimulated by an electrical signal.This work sets an important step towards enabling the enhanced performance of electrochemical actuators based on conductive polymers with designed microstructures.展开更多
The versatile motion capability of snake robots offers themselves robust adaptability in varieties of challenging environments where traditional robots may be incapacitated.This study reports a novel flexible snake ro...The versatile motion capability of snake robots offers themselves robust adaptability in varieties of challenging environments where traditional robots may be incapacitated.This study reports a novel flexible snake robot featuring a rigid-flexible coupling structure and multiple motion gaits.To better understand the robot's behavior,a bending model for the soft actuator is established.Furthermore,a dynamic model is developed to map the relationship between the input air pressure and joint torque,which is the model base for controlling the robot effectively.Based on the wave motion generated by the joint coupling direction function in different planes,multiple motion gait planning methods of the snake-like robot are proposed.In order to evaluate the adaptability and maneuverability of the developed snake robot,extensive experiments were conducted in complex environments.The results demonstrate the robot's effectiveness in navigating through intricate settings,underscoring its potential for applications in various fields.展开更多
Bioinspired Soft Bending Actuators (SBA) are increasingly being used in rehabilitation, assistant robots, and grippers. Despite many investigations on free motion modeling, understanding how these actuators interact w...Bioinspired Soft Bending Actuators (SBA) are increasingly being used in rehabilitation, assistant robots, and grippers. Despite many investigations on free motion modeling, understanding how these actuators interact with the environment requires more detailed research. It is caused by high compliance and nonlinearity of bioinspired soft material, which leads to serious challenges in contact conditions. In this paper, a continuous deformation analysis is presented to describe the free motion nonlinear behavior of the actuator. Based on the achieved result, this study proposes static modeling of SBA affected by a concentrated external force. For this purpose, the finite rigid element method is utilized, which is based on discretizing the actuator into smaller parts and assuming these parts as rigid serial links connected by nonlinear torsional springs. To verify the proposed model, two kinds of forces are considered to be acting on the actuator, i.e. following force and constant direction force. In addition, the effect of gravity on the actuator configuration is also investigated. The validity of the model has been demonstrated through experiments in free motion, contact conditions and the presence of gravity. It generally shows that the prediction error of robot configuration is lower than 7.5%.展开更多
基金National Natural Science Foundation of China(Grant No.U2013212)Key Research and Development Program of Zhejiang(Grant No.2021C04015)Fundamental Research Funds for the Provincial Universities of Zhejiang(Grant No.RF-C2019004)。
文摘Actuator plays a significant role in soft robotics.This paper proposed an ultralong stretchable soft actuator(US2A)with a variable and sizeable maximum elongation.The US2A is composed of a silicone rubber tube and a bellows woven sleeve.The maximal extension can be conveniently regulated by just adjusting the wrinkles’initial angle of the bellows woven sleeve.The kinematics of US2A could be obtained by geometrically analyzing the structure of the bellows woven sleeve when the silicone rubber tube is inflated.Based on the principle of virtual work,the actuating models have been established:the pressure-elongation model and the pressure-force model.These models reflect the influence of the silicone tube’s shell thickness and material properties on the pneumatic muscle’s performance,which facilitates the optimal design of US2A for various working conditions.The experimental results showed that the maximum elongation of the US2A prototype is 257%,and the effective elongation could be variably regulated in the range of 0 and 257%.The proposed models were also verified by pressure-elongation and pressure-force experiments,with an average error of 5%and 2.5%,respectively.Finally,based on the US2A,we designed a pneumatic rehabilitation glove,soft arm robot,and rigid-soft coupling continuous robot,which further verified the feasibility of US2A as a soft driving component.
基金supported by the National Natural Science Foundation of China(Nos.51973155,52173181,and 52173262)Jiangsu Innovation Team Program,Natural Science Foundation of Tianjin(20JCYBJC00810).
文摘In nature,many living organisms exhibiting unique structural coloration and soft-bodied actuation have inspired scientists to develop advanced structural colored soft actuators toward biomimetic soft robots.However,it is challenging to simultaneously biomimic the angle-independent structural color and shape-morphing capabilities found in the plum-throated cotinga flying bird.Herein,we report biomimetic MXene-based soft actuators with angle-independent structural color that are fabricated through controlled self-assembly of colloidal SiO_(2) nanoparticles onto highly aligned MXene films followed by vacuum-assisted infiltration of polyvinylidene fluoride into the interstices.The resulting soft actuators are found to exhibit brilliant,angle-independent structural color,as well as ultrafast actuation and recovery speeds(a maximum curvature of 0.52 mm−1 can be achieved within 1.16 s,and a recovery time of~0.24 s)in response to acetone vapor.As proof-of-concept illustrations,structural colored soft actuators are applied to demonstrate a blue gripper-like bird’s claw that can capture the target,artificial green tendrils that can twine around tree branches,and an artificial multicolored butterfly that can flutter its wings upon cyclic exposure to acetone vapor.The strategy is expected to offer new insights into the development of biomimetic multifunctional soft actuators for somatosensory soft robotics and next-generation intelligent machines.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.51538009 and 51605334)the Natural Science Foundation of Shanghai Municipality,China(Grant No.08002360285)
文摘A new type of soft actuator material-ionic liquid gel (ILG), which consists of HEMA, BMIMBF4, and TiO2, can be transformed into gel state under the irradiation of ultraviolet (UV) light. In this paper, Mooney-Rivlin hyperelastic model of finite element method is proposed for the first time to study the properties of the ILG. It has been proved that the content of TiO2 has a great influence on the properties of the gel, and Young's modulus of the gel increases with the increase of its content, despite of reduced tensile deformation. The results in this work show that when the TiO2 content is 1.0 wt%, a large tensile deformation and a strong Young's modulus can be obtained to be 325% and 7.8 kPa, respectively. The material parameters of ILG with TiO2 content values of 0.2 wt%, 0.5 wt%, 1.0 wt%, and 1.5 wt% are obtained, respectively, through uniaxial tensile tests, including C10, C01, C20, C11, C02, C30, C21, C12, and C03 elements. In this paper, the large-scaled general finite element software ANSYS is used to simulate and analyze the ILG, which is based on SOLID186 element and nonlinear hyperelastic Mooney-Rivlin model. The finite element simulation analysis based stress-strain curves are almost consistent with the experimental stress-strain curves, and hence the finite element analysis of ILG is feasible and credible. This work presents a new direction for studying the performance of soft actuator for the ILG, and also contributes to the design of soft robot actuator.
基金This work was financed by the National Natural Science Foundation of China(No.62175225)Zhejiang Provincial Natural Science Foundation of China(No.LZ21E020004)Fundamental Research Funds for the Provincial Universities of Zhejiang,Young Top Talent Plan of Zhejiang(No.ZJWR0308004).
文摘Remote controlled soft actuators have attracted ever-increasing interest in industrial,medical,robotics,and engineering fields.Soft actuators are charming than normal tools in executing dedicate tasks due to small volume and flexible body they have.However,it remains a challenge to design soft actuator that can adapt to multi-environments under remote stimuli with promising nano materials.Herein,we have developed a kind of near-infrared laser driven soft actuators with multi locomotive modes based on WSe2 and graphene nanosheets heterojunction.Different locomotion modes are driven by photothermal effect induced deformation to adapt to different working conditions.Moreover,the specially designed gripper driven by pulsed laser can lift a heavy load which is four times of its weight.This work broadens the choice of advanced nanomaterials for photothermal conversion of soft actuators.It is promising to realize applications including photothermal therapy and complex environment detection through the combination of the intelligent robot design and optical fiber system.
基金supported by the Fundamental Research Funds for the Central Universities[YWF-22-K-101]National Natural Science Foundation of China[12202120]Science Technology and Innovation Program of Shenzhen[JCYJ20220531095210022].
文摘Liquid crystal elastomers are active materials that combine the anisotropic properties of liquid crystals with the elasticity of polymer networks.The LCEs exhibit remarkable reversible contraction and elongation capabilities in response to external stimuli,rendering them highly promising for diverse applications,such as soft robotics,haptic devices,shape morphing structures,etc,However,the predominant reliance on heating as the driving stimulus for LCEs has limited their practical applications.This drawback can be effectively addressed by incorporating fllers,which can generate heat under various stimuli.The recent progress in LCE composites has significantly expanded the application potential of LCEs.In this minireview,we present the design strategies for soft actuators with LCE composites,followed by a detailed exploration of photothermal and electrothermal LCE.composites as prominent examples.Furthermore,we provide an outlook on the challenges and opportunities in the feld of LCE composites.
基金supported by the National Natural Science Foundation of China(NSFC)(Grant No.21875160)State Key Laboratory for Modification of Chemical Fibers and Polymer Materials(Grant No.KF2219)+1 种基金JK20202A030463,the Natural Science Foundation of Tianjin City(Grant No.20JCQNJC00870)the Scientific Research Project of Tianjin Municipal Education Commission(Grant No.2020KJ054).
文摘As mechanical devices for moving or controlling mechanisms or systems,actuators have attracted increasing attention in various fields.Compared to traditional actuators with rigid structures,soft actuators made up of stimulus-responsive soft materials are more adaptable to complex working conditions due to soft bodies and diverse control styles.Different from plate-shaped soft actuators,which have the limited deformations between two dimensional(2D)and 3D-configurations such as bending and twisting,fiber-shaped soft actuators(FSAs)own intriguing deformation modes to satisfy diverse practical applications.In this mini review,the recent progress on the controlled fabrication of the FSAs is presented.The advantages and disadvantages of each fabrication method are also demonstrated.Subsequently,the as-developed actuation mechanisms of the FSAs are displayed.Additionally,typical examples of the related applications of the FSAs in different fields have been discussed.Finally,an outlook on the development tendency of the FSAs is put forward as well.
基金supported by the National Natural Science Foundation of China(Nos.52122511,61927814,and U20A20290)Anhui Provincial Natural Science Foundation(2308085QF218)+5 种基金China National Postdoctoral Program for Innovative Talents(BX20230351)China Postdoctoral Science Foundation(2023M733382)National Key R&D Program of China(2021YFF0502700)Major Scientific and Technological Projects in Anhui Province(202203a05020014)Fundamental Research Funds for the Central Universities(WK5290000003 and WK2090000058)Youth Innovation Promotion Association CAS(Y2021118)。
文摘Small-scale electromagnetic soft actuators are characterized by a fast response and simplecontrol,holding prospects in the field of soft and miniaturized robotics.The use of liquid metal(LM)to replace a rigid conductor inside soft actuators can reduce the rigidity and enhance the actuation performance and robustness.Despite research efforts,challenges persist in the flexible fabrication of LM soft actuators and in the improvement of actuation performance.To address these challenges,we developed a fast and robust electromagnetic soft microplate actuator based on a laser-induced selective adhesion transfer method.Equipped with unprecedentedly thin LM circuit and customized low Young’s modulus silicone rubber(1.03 kPa),our actuator exhibits an excellent deformation angle(265.25?)and actuation bending angular velocity(284.66 rad·s^(-1)).Furthermore,multiple actuators have been combined to build an artificial gripper with a wide range of functionalities.Our actuator presents new possibilities for designing small-scaleartificial machines and supports advancements in ultrafast soft and miniaturized robotics.
基金financial support from the NSF grant(ECCS-1917630)and University of Missouri-Columbia startup fund.
文摘Laser-assisted process can enable facile,mask-free,large-area,inexpensive,customizable,and miniaturized patterning of laser-induced porous graphene(LIG)on versatile carbonaceous substrates(e.g.,polymers,wood,food,textiles)in a programmed manner at ambient conditions.Together with high tailorability of its porosity,morphology,composition,and electrical conductivity,LIG can find wide applications in emerging bioelectronics(e.g.,biophysical and biochemical sensing)and soft robots(e.g.,soft actuators).In this review paper,we first introduce the methods to make LIG on various carbonaceous substrates and then discuss its electrical,mechanical,and antibacterial properties and biocompatibility that are critical for applications in bioelectronics and soft robots.Next,we overview the recent studies of LIG-based biophysical(e.g.,strain,pressure,temperature,hydration,humidity,electrophysiological)sensors and biochemical(e.g.,gases,electrolytes,metabolites,pathogens,nucleic acids,immunology)sensors.The applications of LIG in flexible energy generators and photodetectors are also introduced.In addition,LIG-enabled soft actuators that can respond to chemicals,electricity,and light stimulus are overviewed.Finally,we briefly discuss the future challenges and opportunities of LIG fabrications and applications.
文摘Soft robots and actuators are emerging devices providing more capabilities in the field of robotics.More flexibility and compliance attributing to soft functional materials used in the fabrication of these devices make them ideal for delivering delicate tasks in fragile environments,such as food and biomedical sectors.Yet,the intuitive nonlinearity of soft functional materials and their anisotropic actuation in compliant mechanisms constitute an existent challenge in improving their performance.Topology optimization(TO)along with four-dimensional(4D)printing is a powerful digital tool that can be used to obtain optimal internal architectures for the efficient performance of porous soft actuators.This paper employs TO analysis for achieving high bending deflection of a 3D printed polyelectrolyte actuator,which shows bending deformations in response to electrical stimuli in an electrolyte solution.The performance of the actuator is studied in terms of maximum bending and actuation rate compared with a solid,uniformly 3D printed and topology-optimized actuator.The experimental results proved the effectiveness of TO on achieving higher bending deformation and actuation rate against a uniformly 3D printed actuator.
基金the National Natural Science Foundation of China(No.11604205)。
文摘The multi-cavity soft actuator is assembled from single-cavity soft actuator through a reasonable geometric distribution.It has the characteristic that the pneumatic soft actuator is driven by its own deformation and has more degrees of freedom.Pneumatic soft actuator is widely used as an emerging discipline and its strong compliance has been greatly developed and applied.However,as the most application potential type of soft actuators,there is still a lack of simple and effective deformation prediction methods for studying the spatial deformation of multi-cavity soft actuators.To solve this problem,a vector equation method is proposed based on the analysis of the principle of the space deformation of the two-cavity,three-cavity and four-cavity soft actuators.Furthermore,a nonlinear mathematical model of the air pressure,space position and deformation trajectory of the soft actuator end is established by combining the vector equation method.Finally,the three-channel soft actuator is verified through experiments.The results show that the mathematical model can better predict the space deformation trajectory of the soft actuator,which provides a new research method for studying the space deformation of the multi-channel soft actuator.
基金Supported by National Natural Science Foundation of China(Grant Nos.51975505 and U2037202)Science and Technology Project of Hebei Education Department(Grant No.SLRC2019039)+1 种基金Postgraduate Innovation Ability Cultivation Funded Project of Hebei Province(Grant No.CXZZBS2021135)Open Project of Hebei Industrial Manipulator Control and reliability Technology Innovation Center,Hebei University of Water Resources and Electric Engineering(Grant No.JXKF2102).
文摘Dyskinesia of the upper limbs caused by stroke,sports injury,or trafc accidents limits the ability to perform the activities of daily living.Besides the necessary medical treatment,correct and scientifc rehabilitation training for the injured joint is an important auxiliary means during the treatment of the efected upper limb.Conventional upperlimb rehabilitation robots have some disadvantages,such as a complex structure,poor compliance,high cost,and poor portability.In this study,a novel soft wearable upper limb rehabilitation robot(SWULRR)with reinforced soft pneumatic actuators(RSPAs)that can withstand high pressure and featuring excellent loading characteristics was developed.Driven by RSPAs,this portable SWULRR can perform rehabilitation training of the wrist and elbow joints.In this study,the kinematics of an SWULRR were analyzed,and the force and motion characteristics of RSPA were studied experimentally.The results provide a reference for the development and application of wearable upper limb rehabilitation robots.An experimental study on the rotation angle of the wrist and the pressure of the RSPA was conducted to test the efect of the rehabilitation training and verify the rationality of the theoretical model.The process of wrist rehabilitation training was tested and evaluated,indicating that SWULRR with RSPAs will enhance the fexibility,comfort,and safety of rehabilitation training.This work is expected to promote the development of wearable upper-limb rehabilitation robots based on modular reinforced soft pneumatic actuators.
基金the National Natural Science Foundation of China(Nos.11572002 and 12002032)the China Postdoctoral Science Foundation(Nos.BX20200056 and 2020M670149)。
文摘The soft robotics display huge advantages over their rigid counterparts when interacting with living organisms and fragile objects.As one of the most efficient actuators toward soft robotics,the soft pneumatic actuator(SPA)can produce large,complex responses with utilizing pressure as the only input source.In this work,a new approach that combines digital light processing(DLP)and injection-assisted post-curing is proposed to create SPAs that can realize different functionalities.To enable this,we develop a new class of photo-cross linked elastomers with tunable mechanical properties,good stretchability,and rapid curing speed.By carefully designing the geometry of the cavities embedded in the actuators,the resulting actuators can realize contracting,expanding,flapping,and twisting motions.In addition,we successfully fabricate a soft self-sensing bending actuator by injecting conductive liquids into the three-dimensional(3D)printed actuator,demonstrating that the present method has the potential to be used to manufacture intelligent soft robotic systems.
基金supported by the National Natural Science Foundation of China(Grant No. 52075556)the Key R&D Program of Hunan Province(Grant No. 2021SK2016)。
文摘The human wrist, a complex articulation of skeletal muscles and two-carpal rows, substantially contributes to improvements in maneuverability by agilely performing three-degree-of-freedom(3-DOF) orienting tasks and regulating stiffness according to variations in interaction forces. However, few soft robotic wrists simultaneously demonstrate dexterous 3-DOF motion and variable stiffness;in addition, they do not fully consider a soft-rigid hybrid structure of integrated muscles and two carpal rows.In this study, we developed a soft-rigid hybrid structure to design a biomimetic soft robotic wrist(BSRW) that is capable of rotating in the x and y directions, twisting around the z-axis, and possessing stiffness-tunable capacity. To actuate the BSRW, a lightweight soft-ring-reinforced bellows-type pneumatic actuator(SRBPA) with large axial, linear deformation(η_(lcmax)=70.6%,η_(lemax)=54.3%) and small radial expansion(η_(demax)=3.7%) is designed to mimic the motion of skeletal muscles. To represent the function of two-carpal rows, a compact particle-jamming joint(PJJ) that combines particles with a membrane-covered ballsocket mechanism is developed to achieve various 3-DOF motions and high axial load-carrying capacity(>60 N). By varying the jamming pressure, the stiffness of the PJJ can be adjusted. Finally, a centrally positioned PJJ and six independently actuated SRBPAs, which are in an inclined and antagonistic arrangement, are sandwiched between two rigid plates to form a flexible,stable, and compact BSRW. Such a structure enables the BSRW to have a dexterous 3-DOF motion, high load-carrying ability,and stiffness tunability. Experimental analysis verify 3-DOF motion of BSRW, producing force of 29.6 N and 36 N and torque of2.2 Nm in corresponding rotations. Moreover, the range of rotational angle and stiffness-tuning properties of BSRW are studied by applying jamming pressure to the PJJ. Finally, a system combining a BSRW and a soft enclosing gripper is proposed to demonstrate outstanding manipulation capability in potential applications.
基金supported by International Cooperation Program of the Natural Science Foundation of China(Grant No.52261135542)Zhejiang Provincial Natural Science Foundation of China(Grant No.LD22E050002)+1 种基金Zhejiang University Global Partnership Fundgrateful to the Russian Science Foundation(Grant No.23-43-00057)for financial support。
文摘Real-time proprioception presents a significant challenge for soft robots due to their infinite degrees of freedom and intrinsic compliance.Previous studies mostly focused on specific sensors and actuators.There is still a lack of generalizable technologies for integrating soft sensing elements into soft actuators and mapping sensor signals to proprioception parameters.To tackle this problem,we employed multi-material 3D printing technology to fabricate sensorized soft-bending actuators(SBAs)using plain and conductive thermoplastic polyurethane(TPU)filaments.We designed various geometric shapes for the sensors and investigated their strain-resistive performance during deformation.To address the nonlinear time-variant behavior of the sensors during dynamic modeling,we adopted a data-driven approach using different deep neural networks to learn the relationship between sensor signals and system states.A series of experiments in various actuation scenarios were conducted,and the results demonstrated the effectiveness of this approach.The sensing and shape prediction steps can run in real-time at a frequency of50 Hz on a consumer-level computer.Additionally,a method is proposed to enhance the robustness of the learning models using data augmentation to handle unexpected sensor failures.All the methods are efficient,not only for in-plane 2D shape estimation but also for out-of-plane 3D shape estimation.The aim of this study is to introduce a methodology for the proprioception of soft pneumatic actuators,including manufacturing and sensing modeling,that can be generalized to other soft robots.
基金This work was supported by Japan Society for the Promotion of Science,Japan for their support under Grants-in-Aid for Scientific Research on Innovative Areas(18H05473)the JSPS,Japan KAKENHI(21J15489 and 23K13290).
文摘Soft robotics is a breakthrough technology to support human-robot interactions.The soft structure of a soft robot can increase safety during human and robot interactions.One of the promising soft actuators for soft robotics is dielectric elastomer actuators(DEAs).DEAs can operate silently and have an excellent energy density.The simple structure of DEAs leads to the easy fabrication of soft actuators.The simplicity combined with silent operation and high energy density make DEAs interesting for soft robotics researchers.DEAs actuation follows the Maxwell-pressure principle.The pressure produced in the DEAs actuation depends much on the voltage applied.Common DEAs requires high voltage to gain an actuation.Since the power consumption of DEAs is in the milli-Watt range,the current needed to operate the DEAs can be neglected.Several commercially available DC-DC converters can convert the volt range to the kV range.In order to get a voltage in the 2-3 kV range,the reliable DC-DC converter can be pricy for each device.This problem hinders the education of soft actuators,especially for a newcomer laboratory that works in soft electric actuators.This paper introduces an entirely do-it-yourself(DIY)Ultrahigh voltage amplifier(UHV-Amp)for education in soft robotics.UHV-Amp can amplify 12 V to at a maximum of 4 kV DC.As a demonstration,we used this UHV-Amp to test a single layer of powdered-based DEAs.The strategy to build this educational type UHV-Amp was utilizing a Cockcroft-Walton circuit structure to amplify the voltage range to the kV range.In its current state,the UHV-Amp has the potential to achieve approximately 4 kV.We created a simple platform to control the UHV-Amp from a personal computer.In near future,we expect this easy control of the UHV-Amp can contribute to the education of soft electric actuators.
基金supported by the National Natural Science Foundation of China(Grant No.52205073)Zhejiang Provincial Natural Science Foundation of China(Grant No.LD22E050002)+1 种基金China National Postdoctoral Program for Innovative Talents(Grant No.BX2021258)China Postdoctoral Science Foundation(Grant No.2022M710125)。
文摘Designing soft robots that are able to perceive unstructured,dynamic environments and their deformations has been a long-term goal.Previously reported self-sensing soft actuators were mostly constructed via integrating separate actuators and sensors.The actuation performances and the sensing reliability are affected owing to the unmatched materials and weak connections.Realizing a seamless integration of soft actuators and sensors remains a grand challenge.Here,we report a fabrication strategy to endow soft actuators with sensing capability and programmable actuation performances.The foam inside the actuator functions as actuator and sensor simultaneously,effectively addressing the conformability and connection reliability issues that existed in current self-sensing actuators.The actuators are lightweight(a decrease of 58%in weight),powerful(lifting a load of 433 times of its own weight),and versatile(coupling twisting and contraction motions).Furthermore,the actuators are able to detect multiple physical stimuli with high reliability,demonstrating their exteroception and proprioception capability.Two self-sensing soft robotic prototypes,including a bionic bicep and a bionic neck,are constructed to illustrate their multifunctionality.Our study opens up new possibilities for the design of soft actuators and has promising potential in a variety of applications,ranging from human-robot interaction,soft orthotics,to wearable robotics.
基金This work was supported by China Postdoctoral Science Foundation(2022M711372)Postdoctoral Research Program of Jiangsu Province(2021K544C)+4 种基金the General Program of Natural Science Foundation for Higher Education in Jiangsu Province(21KJB510004)G.Cheng acknowledges the support from young&middle-aged academic leaders of Jiangsu Blue Project and Jiangsu 333 talent fundL.Xu acknowledges the support from National Natural Science Foundation of China(NSFC No.51905222)Natural Science Foundation of Jiangsu Province(Grant No.BK20211068)This work was also supported by International Science and Technology Cooperation Project in Zhenjiang City(Grant No:GJ2020009)。
文摘Electrochemical actuators based on conductive polymers are emerging as a strong competitive in the field of soft actuators because of their intrinsically conformable/elastic nature,low cost,low operating voltage and air-working ability.Recent development has shown that adding electroactive materials,such as CNT and graphene,can improve their actuation performance.Despite the complex material systems used,their output strains(one of the key factors)are generally lower than 1%,which limited further applications of them in multiple scenarios.Here,we report soft electrochemical actuators based on conductive polymer ionogels by embedding polyaniline particles between the PEDOT:PSS nanosheets.Results show that such a hierarchical structure not only leads to a high conductivity(1250 S/cm)but also improved electrochemical activities.At a low operating voltage of 1 V,the maximum strain of these soft actuators reaches an exceptional value of 1.5%,with a high blocking force of 1.3 mN.Using these high-performance electrochemical actuators,we demonstrate soft grippers for manipulating object and a bionic flower stimulated by an electrical signal.This work sets an important step towards enabling the enhanced performance of electrochemical actuators based on conductive polymers with designed microstructures.
基金support by the Shenzhen-Hong Kong-Macao Science and Technology Project(Category C)sponsored by the Science Technology and Innovation Committee of Shenzhen Municipality(SGDX20201103093003017)Shenzhen Key Basic Research Project(JCYJ20200109114827177)Hong Kong RGC General Research Fund(CityU 11216421).
基金financially supported by the Joint Fund of National Natural Science Foundation of China with Shenzhen City(U2013212)the National Key R&D Program of China(2020YFB1313001).
文摘The versatile motion capability of snake robots offers themselves robust adaptability in varieties of challenging environments where traditional robots may be incapacitated.This study reports a novel flexible snake robot featuring a rigid-flexible coupling structure and multiple motion gaits.To better understand the robot's behavior,a bending model for the soft actuator is established.Furthermore,a dynamic model is developed to map the relationship between the input air pressure and joint torque,which is the model base for controlling the robot effectively.Based on the wave motion generated by the joint coupling direction function in different planes,multiple motion gait planning methods of the snake-like robot are proposed.In order to evaluate the adaptability and maneuverability of the developed snake robot,extensive experiments were conducted in complex environments.The results demonstrate the robot's effectiveness in navigating through intricate settings,underscoring its potential for applications in various fields.
文摘Bioinspired Soft Bending Actuators (SBA) are increasingly being used in rehabilitation, assistant robots, and grippers. Despite many investigations on free motion modeling, understanding how these actuators interact with the environment requires more detailed research. It is caused by high compliance and nonlinearity of bioinspired soft material, which leads to serious challenges in contact conditions. In this paper, a continuous deformation analysis is presented to describe the free motion nonlinear behavior of the actuator. Based on the achieved result, this study proposes static modeling of SBA affected by a concentrated external force. For this purpose, the finite rigid element method is utilized, which is based on discretizing the actuator into smaller parts and assuming these parts as rigid serial links connected by nonlinear torsional springs. To verify the proposed model, two kinds of forces are considered to be acting on the actuator, i.e. following force and constant direction force. In addition, the effect of gravity on the actuator configuration is also investigated. The validity of the model has been demonstrated through experiments in free motion, contact conditions and the presence of gravity. It generally shows that the prediction error of robot configuration is lower than 7.5%.