查看更多>>摘要：Traditional robotic grippers encounter significant challenges when handling small objects in confined spaces,underscor-ing the need for innovative instruments with enhanced space efficiency and adaptability.Erodium cicutarium awns have evolved hygroresponsive helical deformation,efficiently driving seeds into soil crevices with limited space utilization.Drawing inspiration from this natural mechanism,we developed a biomimetic thin-walled actuator with water-responsive helical capabilities.It features a composite material structure comprising common engineering materials with low toxic-ity.Leveraging fused deposition modeling 3D printing technology and the composite impregnation process,the actuator's manufacturing process is streamlined and cost-effective,suitable for real-world applications.Then,a mathematical model is built to delineate the relationship between the biomimetic actuator's key structural parameters and deformation charac-teristics.The experimental results emphasize the actuator's compact dimension(0.26 mm thickness)and its capability to form a helical tube under 5 mm diameter within 60 s,demonstrating outstanding space efficiency.Moreover,helical char-acteristics and stiffness of the biomimetic actuators are configurable through precise modifications to the composite mate-rial structure.Consequently,it is capable of effectively grasping an object smaller than 3 mm.The innovative mechanism and design principles hold promise for advancing robotic technology,particularly in fields requiring high space efficiency and adaptability,such as fine tubing decongestion,underwater sampling,and medical endoscopic surgery.
查看更多>>摘要：Delaying the sinusoidal plunging in the middle of the up-and down stroke is studied.This form of kinematics can appear if the flapping mechanism is malfunctioning,or while large birds fly in some cases.Aim of this study is to understand the effect of pausing the airfoil during plunging in the equilibrium position.The paused plunging is modelled mathematically by means of a sinusoidal waveform raised to the third power.Evaluation of this waveform is done on two stages;the wake pattern analysis and the aerodynamic and propulsive analysis.Studying this waveform reveals a robust way to generate two triads wake pattern instead of the regular reverse von Karman vortex wake pattern.The thrust generation mechanism is presented.The performance evaluation is done based on the thrust,lift,and power coefficients and the propulsive efficiency at different point in the nondimensional amplitude-reduced frequency space.Regression modeling methods are utilized to stand on the performance of the paused waveform with respect to the regular sinusoidal waveform.These findings underscore the potential of the proposed waveform as a promising alternative for enhancing the aerodynamic performance and propulsive efficiency in the design of Micro Air Vehicles(MAVs),a rapidly evolving field.
查看更多>>摘要：Felids,during intense activities such as jumping and sprinting,adjust their posture by twisting and stretching their body to disperse limb impact and minimize injury.This self-stabilization mechanism has garnered significant attention for inspir-ing biometric robot design.This study investigates the flexibility and cushioning characteristics of a cat's spine,focusing on its biomechanical properties.A high-fidelity 3D model was used to test the range of motion(ROM)under six condi-tions,simulate dorsiflexion to analyze stress distribution.The torsional and compressive stiffness were tested by using five cat spinal specimens.the flexibility principles of the flexible cat's spine were explained via morphological insights.Results indicate that the cat spine has the least rotational stiffness in axial rotation,followed by extension and lateral bending,with a compressive stiffness of 53.62±4.68 N/mm.Stress during dorsiflexion is evenly distributed across vertebrae.The vertebrae heights account for 90.34％of total spinal length with a mean height-to-width ratio of 1.04.Cats'spines,with more articulations and elongated vertebrae,allow for significant twisting and bending,aiding in rapid body posture adjust-ments and impact mitigation.These biomechanical traits could inspire the design of robots for confined rescue operations.
查看更多>>摘要：In this study,we present the design and development evaluation of BalanSENS toward the realization of the Integrated Balance Rehabilitation(I-BaR)framework.BalanSENS is designed to encourage active participation by integrating multi-sensory information with the co-improvement of sensory and motor functions.Moreover,it can offer individual rehabili-tation design with the integration of three phases.The first phase provides foot-ankle muscle activation and movement sensation development.In the second phase,sensory weighting skills and upper extremities independence can be improved by using multi-sensory input.In the last/stepping phase,walking parameters are aimed to be improved with modulated distance.The parallel manipulator is designed through simulations to determine actuation properties and analyze the load-bearing capacity and feasibility of the materials.Drawing from simulation outcomes,an operational 3 DoF platform is constructed to demonstrate their design suitability for the I-BaR framework.Furthermore,design evaluations demonstrated promising results in quantifying force and real-time data monitoring during the passive ankle preparation phase.
查看更多>>摘要：Along with the flourishing of brain-computer interface technology,the brain-to-brain information transmission between different organisms has received high attention in recent years.However,specific information transmission mode and implementation technology need to be further studied.In this paper,we constructed a brain-to-brain information transmis-sion system between pigeons based on the neural information decoding and electrical stimulation encoding technologies.Our system consists of three parts:(1)the"perception pigeon"learns to distinguish different visual stimuli with two discrepant frequencies,(2)the computer decodes the stimuli based on the neural signals recorded from the"perception pigeon"through a frequency identification algorithm(neural information decoding)and encodes them into different kinds of electrical pulses,(3)the"action pigeon"receives the Intracortical Microstimulation(ICMS)and executes correspond-ing key-pecking actions through discriminative learning(electrical stimulation encoding).The experimental results show that our brain-to-brain system achieves information transmission from perception to action between two pigeons with the average accuracy of about 72％.Our study verifies the feasibility of information transmission between inter-brain based on neural information decoding and ICMS encoding,providing important technical methods and experimental program references for the development of brain-to-brain communication technology.
查看更多>>摘要：The anthropometric differences between European/American and Chinese population are remarkable and have significant influences on pedestrian kinematics and injury response in vehicle crashes.Therefore,the current study aims to develop.and validate a Finite Element(FE)human body model representing the anthropometry of Chinese 50th percentile adult male for pedestrian safety analysis and development of Chinese ATDs(Anthropomorphic Test Devices).Firstly,a human body pedestrian model,named as C-HBM(Chinese Human Body Model),was developed based on the medical image data of a volunteer selected according to both anthropometry and anatomy characteristics of 50th percentile Chinese adult male.Then,the biofidelity of the C-HBM pedestrian model was validated against cadaver impact test data reported in the literature at the segment and full-body level.Finally,the validated C-HBM pedestrian model was employed to predict Chinese pedestrian injuries in real world vehicle crashes.The results indicate that the C-HBM pedestrian model has a good capability in predicting human body mechanical response in cadaver tests and Chinese leg and thorax injuries in vehicle crashes.Kinematic analysis shows that the C-HBM pedestrian model has less sliding on the hood surface,shorter movement in the horizontal direction,and higher pelvis displacement in the vertical direction than cadavers and the pedestrian model in the anthropometry of westerner due to anthropometric differences in the lower limbs.The currently developed C-HBM pedestrian model provides a basic tool for vehicle safety design and evaluation in China market,and for development of Chinese ATDs.
查看更多>>摘要：Micro-and nano-structures are intentionally incorporated into various biological surfaces,such as fish scales,snakeskin,and burr-covered plant leaves,to enhance their interactions with other surfaces.The mechanical anisotropy affects fric-tion,interlocking,propulsion,and mobility on substrates.This study investigates a novel method for developing a robust,stratified,soft,lubricating coating on a surface.3-Methacryloyloxypropyl-trimethoxysilane(MPS)is a cohesive adhesion promoter that functions by infiltrating Polydimethylsiloxane(PDMS)silicone elastomers to maintain low friction levels and high mechanical load-bearing capacity.MPS makes it easier for organic and inorganic materials to adhere to the surface of the initiator layer P(AAm-co-AA-co-PDMS/Fe).We investigate how the tough hydrogel layer of the module impacts the lubricating ability of the multilayer coating when the tough hydrogel layer of the module adheres to the bio-based polyurethane substrate.After 1,000 sliding cycles with a 1 N load,the improved PDMS's Coefficient of Friction(COF)remains steady and low(COF＜0.81).We recommend using the suggested structure and a standard set of optimal variables to enhance the functional efficiency of such systems.In conclusion,we have demonstrated the optimal simula-tion of these parameters for stimulus-responsive,adjustable surface systems.
查看更多>>摘要：Photovoltaic(PV)power generation is highly regarded for its capability to transform solar energy into electrical power.However,in real-world applications,PV modules are prone to issues such as increased self-heating and surface dust accu-mulation,which contribute to a reduction in photoelectric conversion efficiency.Furthermore,elevated temperatures can adversely affect the components'operational longevity.To augment the efficiency and extend the lifespan of PV modules,it is crucial to implement cooling strategies and periodic surface dust removal.In this research,we introduce a composite PV module design that amalgamates a hygroscopic hydrogel with self-cleaning attributes.The design incorporates a super-hydrophobic polydimethylsiloxane(PDMS)film as its exposed surface layer and employs a PAM-CaCl2-SiC hygroscopic hydrogel for rear cooling.This arrangement is intended to facilitate efficient surface self-cleaning and passive cooling of the composite PV module.Experimental studies were conducted to evaluate the performance of this innovative composite PV module design,and the results showed that the composite PV panel had an increase of about 1.39％in power genera-tion compared to an ordinary PV panel in the spring of Shenzhen,China.
查看更多>>摘要：The shortage of transplantable skin is the leading cause of death in patients with extensive skin defect.Addressing this chal-lenge urgently requires the development of skin substitutes capable of wound repair and facilitating skin regeneration.In this study,a biomimetic bilayer skin tissue model consisting of collagen,gelatin/sodium alginate,fibroblasts,human umbilical vein endothelial cells,keratinocytes,melanocytes,and verteporfin was devised.Then,the skin model was fabricated using precise extrusion/inkjet bioprinters,and it reconstruction capabilities were evaluated through skin defect repair experiments.The printed skin tissue reduced the inflammatory response of the wound by 38％and inhibited the expression of TGF-β and YAP,and promoted the transformation of macrophages from Ml phenotype to M2 phenotype,thus promoting the reason-able reconstruction of fibronectin and collagen on the wound,finally promoting the wound healing,and reducing the wound contraction and scar formation.In addition,the proliferation and differentiation of human umbilical vein endothelial cells,keratinocytes,and melanocytes in printed skin increased the number of regenerated blood vessels by 123％,while promoting the reconstruction of multilayer epidermal structure and skin color.The outcomes of this investigation present a promising skin model and therapeutic strategy for skin injury,offering a potential avenue for the reconstruction of skin structure and function.
查看更多>>摘要：Aiming to address the issues of poor optimization-seeking ability and easily falling into local optimization of the Snow Ablation Optimizer(SAO),a Physically Hybrid strategy-based Improved Snow Ablation Optimizer(PHISAO)is pro-posed.In this paper,a snow blowing strategy was introduced during the initialization phase of the population to improve population diversity.Secondly,the dual-population iterative strategy of SAO has been replaced by a multi-population iterative strategy,which is supplemented with a position update formula for the water evaporation phase.Additionally,Cauchy mutation perturbation has been introduced in the snow melting phase.This set of improvements better balances the exploration and exploitation phases of the algorithm,enhancing its ability to pursue excellence.Finally,a fluid acti-vation strategy is added to activate the potential of the algorithm when its update iterations enter stagnation,helping the algorithm to escape from the local optimum.Comparison experiments between PHISAO and six metaheuristics were conducted on the CEC(Congress on Evolutionary Computation)-2017 and CEC-2022 benchmark suites.The experimental results demonstrate that the PHISAO algorithm exhibits excellent performance and robustness.In addition,the PHISAO is applied into the unmanned aerial vehicle trajectory planning problem together with particle swarm optimization,beluga whale optimization,sand cat swarm optimization,and SAO.The simulation results show that the proposed PHISAO can plan the optimal trajectory in all two different maps.The proposed PHISAO objective function values were reduced by an average of 29.49％(map 1),and 18.34％(map 2)compared to SAO.
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