Pub Date : 2024-08-07DOI: 10.1088/1748-3190/ad6544
Ji Hou, Changling He, Tao Li, Chunze Zhang, Qin Zhou
The reef ecosystem plays a vital role as a habitat for fish species with limited swimming capabilities, serving not only as a sanctuary and food source but also influencing their behavioral tendencies. Understanding the intricate mechanism through which fish adeptly navigate the moving targets within reef environments within complex water flow, all while evading obstacles and maintaining stable postures, has remained a challenging and prominent subject in the realms of fish behavior, ecology, and biomimetics alike. An integrated simulation framework is used to investigate fish predation problems within intricate environments, combining deep reinforcement learning algorithms (DRL) with high-precision fluid-structure interaction numerical methods-immersed boundary lattice Boltzmann method (lB-LBM). The Soft Actor-Critic (SAC) algorithm is used to improve the intelligent fish's capacity for random exploration, tackling the multi-objective sparse reward challenge inherent in real-world scenarios. Additionally, a reward shaping method tailored to its action purposes has been developed, capable of capturing outcomes and trend characteristics effectively. The convergence and robustness advantages of the method elucidated in this paper are showcased through two case studies: one addressing fish capturing randomly moving targets in hydrostatic flow field, and the other focusing on fish counter-current foraging in reef environments to capture drifting food. A comprehensive analysis was conducted of the influence and significance of various reward types on the decision-making processes of intelligent fish within intricate environments.
{"title":"Learning obstacle avoidance and predation in complex reef environments with deep reinforcement learning.","authors":"Ji Hou, Changling He, Tao Li, Chunze Zhang, Qin Zhou","doi":"10.1088/1748-3190/ad6544","DOIUrl":"10.1088/1748-3190/ad6544","url":null,"abstract":"<p><p>The reef ecosystem plays a vital role as a habitat for fish species with limited swimming capabilities, serving not only as a sanctuary and food source but also influencing their behavioral tendencies. Understanding the intricate mechanism through which fish adeptly navigate the moving targets within reef environments within complex water flow, all while evading obstacles and maintaining stable postures, has remained a challenging and prominent subject in the realms of fish behavior, ecology, and biomimetics alike. An integrated simulation framework is used to investigate fish predation problems within intricate environments, combining deep reinforcement learning algorithms (DRL) with high-precision fluid-structure interaction numerical methods-immersed boundary lattice Boltzmann method (lB-LBM). The Soft Actor-Critic (SAC) algorithm is used to improve the intelligent fish's capacity for random exploration, tackling the multi-objective sparse reward challenge inherent in real-world scenarios. Additionally, a reward shaping method tailored to its action purposes has been developed, capable of capturing outcomes and trend characteristics effectively. The convergence and robustness advantages of the method elucidated in this paper are showcased through two case studies: one addressing fish capturing randomly moving targets in hydrostatic flow field, and the other focusing on fish counter-current foraging in reef environments to capture drifting food. A comprehensive analysis was conducted of the influence and significance of various reward types on the decision-making processes of intelligent fish within intricate environments.</p>","PeriodicalId":55377,"journal":{"name":"Bioinspiration & Biomimetics","volume":null,"pages":null},"PeriodicalIF":3.1,"publicationDate":"2024-08-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141725141","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"计算机科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-08-06DOI: 10.1088/1748-3190/ad679c
Leonardo M Santos, Amy Lang, Redha Wahidi, Andrew Bonacci, Sashank Gautam, Jacob Parsons
This smooth flat experimental study investigates the capability of mako shark scales to control flow separation when placed downstream of the onset of turbulent boundary layer separation and within the reattachment region. The objective of the study is to validate the hypothesis that the shark scales' bristling and recoiling would prevent the flow separation on the flank region (the fastest flow region) of the shark. A rotating cylinder was used to induce an adverse pressure gradient over a flat plate to produce a region of separated flow where the shark skin specimen was mounted. Two types of mako shark scales (flank (B2) and between flank and dorsal fin (B1)) were positioned in the preferred flow direction on a flat plate. The B2 scales are slender, 200μm tall, and can bristle up to 50°. In contrast, B1 scales are wider, shorter, and can bristle at 30°. The bristling angle and shape are the main mechanisms by which the scales act to inhibit flow from moving upstream near the wall. Thus, the difference in the bristling angles and structures of the scales is attributed to the fact that the B2 scales function in a thicker boundary layer (behind the shark's gills) where they must bristle sufficiently high into the boundary layer to control the flow separation, and because the adverse pressure gradient in this region is higher where flow separation is more likely. The scales are placed in the reattachment region to elucidate their ability to control and reattach an already separated turbulent flow. The results show that B2 scales placed in the reattachment region reduce the size of the turbulent separation bubble and decrease the turbulent kinetic energy, while B1 scales have the opposite effect.
{"title":"The effect of shortfin mako shark skin at the reattachment of a separated turbulent boundary layer.","authors":"Leonardo M Santos, Amy Lang, Redha Wahidi, Andrew Bonacci, Sashank Gautam, Jacob Parsons","doi":"10.1088/1748-3190/ad679c","DOIUrl":"10.1088/1748-3190/ad679c","url":null,"abstract":"<p><p>This smooth flat experimental study investigates the capability of mako shark scales to control flow separation when placed downstream of the onset of turbulent boundary layer separation and within the reattachment region. The objective of the study is to validate the hypothesis that the shark scales' bristling and recoiling would prevent the flow separation on the flank region (the fastest flow region) of the shark. A rotating cylinder was used to induce an adverse pressure gradient over a flat plate to produce a region of separated flow where the shark skin specimen was mounted. Two types of mako shark scales (flank (B2) and between flank and dorsal fin (B1)) were positioned in the preferred flow direction on a flat plate. The B2 scales are slender, 200<i>μ</i>m tall, and can bristle up to 50°. In contrast, B1 scales are wider, shorter, and can bristle at 30°. The bristling angle and shape are the main mechanisms by which the scales act to inhibit flow from moving upstream near the wall. Thus, the difference in the bristling angles and structures of the scales is attributed to the fact that the B2 scales function in a thicker boundary layer (behind the shark's gills) where they must bristle sufficiently high into the boundary layer to control the flow separation, and because the adverse pressure gradient in this region is higher where flow separation is more likely. The scales are placed in the reattachment region to elucidate their ability to control and reattach an already separated turbulent flow. The results show that B2 scales placed in the reattachment region reduce the size of the turbulent separation bubble and decrease the turbulent kinetic energy, while B1 scales have the opposite effect.</p>","PeriodicalId":55377,"journal":{"name":"Bioinspiration & Biomimetics","volume":null,"pages":null},"PeriodicalIF":3.1,"publicationDate":"2024-08-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141762846","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"计算机科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-08-06DOI: 10.1088/1748-3190/ad6726
Md Arif Billah, Imraan A Faruque
Despite progress developing experimentally-consistent models of insect in-flight sensing and feedback for individual agents, a lack of systematic understanding of the multi-agent and group performance of the resulting bio-inspired sensing and feedback approaches remains a barrier to robotic swarm implementations. This study introduces the small-target motion reactive (STMR) swarming approach by designing a concise engineering model of the small target motion detector (STMD) neurons found in insect lobula complexes. The STMD neuron model identifies the bearing angle at which peak optic flow magnitude occurs, and this angle is used to design an output feedback switched control system. A theoretical stability analysis provides bi-agent stability and state boundedness in group contexts. The approach is simulated and implemented on ground vehicles for validation and behavioral studies. The results indicate despite having the lowest connectivity of contemporary approaches (each agent instantaneously regards only a single neighbor), STMR achieves collective group motion. STMR group level metric analysis also highlights continuously varying polarization and decreasing heading variance.
{"title":"Visually guided swarm motion coordination via insect-inspired small target motion reactions.","authors":"Md Arif Billah, Imraan A Faruque","doi":"10.1088/1748-3190/ad6726","DOIUrl":"10.1088/1748-3190/ad6726","url":null,"abstract":"<p><p>Despite progress developing experimentally-consistent models of insect in-flight sensing and feedback for individual agents, a lack of systematic understanding of the multi-agent and group performance of the resulting bio-inspired sensing and feedback approaches remains a barrier to robotic swarm implementations. This study introduces the small-target motion reactive (STMR) swarming approach by designing a concise engineering model of the small target motion detector (STMD) neurons found in insect lobula complexes. The STMD neuron model identifies the bearing angle at which peak optic flow magnitude occurs, and this angle is used to design an output feedback switched control system. A theoretical stability analysis provides bi-agent stability and state boundedness in group contexts. The approach is simulated and implemented on ground vehicles for validation and behavioral studies. The results indicate despite having the lowest connectivity of contemporary approaches (each agent instantaneously regards only a single neighbor), STMR achieves collective group motion. STMR group level metric analysis also highlights continuously varying polarization and decreasing heading variance.</p>","PeriodicalId":55377,"journal":{"name":"Bioinspiration & Biomimetics","volume":null,"pages":null},"PeriodicalIF":3.1,"publicationDate":"2024-08-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141762847","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"计算机科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Legged robots have received widespread attention in academia and engineering owing to their excellent terrain adaptability. However, most legged robots can only adapt to high-hardness environments instead of flexible environments. Expanding the motion range of legged robots to water is a promising but challenging work. Inspired by basilisk lizards which can run on water surfaces by feet, this paper proposes a bipedal robot for water running by hydrodynamics instead of buoyancy. According to the motion parameters of the basilisk lizard during water running, a single-degree of freedom bipedal mechanism is proposed to reproduce the motion trajectory of the feet of the basilisk lizard. Scale optimization is conducted by a particle swarm optimization algorithm to determine the geometrical parameters of the mechanism. The effects of motion frequency and foot area on mechanism performance are studied and the optimal solutions are determined by the maximum single-cycle lift impulse through numerical calculations. A bipedal water running robot prototype was fabricated, and the experimental results show that the prototype can generate enough support for the robot running on the water by providing a maximum lift of 2.4 times its weight (160 g) and reaching a horizontal forward speed range of 0.3-0.8 m s-1, compared with the basilisk lizard weighs 2-200 g, generates a lift impulse that is 111%-225% of its body weight, and moves at a speed of 1.3 ± 0.1 m s-1.
{"title":"Design of a bipedal robot for water running based on a six-linkage mechanism inspired by basilisk lizards.","authors":"Jingfu Zhao, Jiaxu Han, Wenjie Ju, Wenjie Zhang, Zhenmin Hou, Chenya Bian, Rongjie Kang, Jiansheng Dai, Zhibin Song","doi":"10.1088/1748-3190/ad63ea","DOIUrl":"10.1088/1748-3190/ad63ea","url":null,"abstract":"<p><p>Legged robots have received widespread attention in academia and engineering owing to their excellent terrain adaptability. However, most legged robots can only adapt to high-hardness environments instead of flexible environments. Expanding the motion range of legged robots to water is a promising but challenging work. Inspired by basilisk lizards which can run on water surfaces by feet, this paper proposes a bipedal robot for water running by hydrodynamics instead of buoyancy. According to the motion parameters of the basilisk lizard during water running, a single-degree of freedom bipedal mechanism is proposed to reproduce the motion trajectory of the feet of the basilisk lizard. Scale optimization is conducted by a particle swarm optimization algorithm to determine the geometrical parameters of the mechanism. The effects of motion frequency and foot area on mechanism performance are studied and the optimal solutions are determined by the maximum single-cycle lift impulse through numerical calculations. A bipedal water running robot prototype was fabricated, and the experimental results show that the prototype can generate enough support for the robot running on the water by providing a maximum lift of 2.4 times its weight (160 g) and reaching a horizontal forward speed range of 0.3-0.8 m s<sup>-1</sup>, compared with the basilisk lizard weighs 2-200 g, generates a lift impulse that is 111%-225% of its body weight, and moves at a speed of 1.3 ± 0.1 m s<sup>-1</sup>.</p>","PeriodicalId":55377,"journal":{"name":"Bioinspiration & Biomimetics","volume":null,"pages":null},"PeriodicalIF":3.1,"publicationDate":"2024-08-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141629335","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"计算机科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-07-29DOI: 10.1088/1748-3190/ad649d
Nicholas Mazzoleni, Matthew Bryant
In traditional hydraulic robotics, actuators must be sized for the highest possible load, resulting in significant energy losses when operating in lower force regimes. Variable recruitment fluidic artificial muscle (FAM) bundles offer a novel bio-inspired solution to this problem. Divided into individual MUs, each with its own control valve, a variable recruitment FAM bundle uses a switching control scheme to selectively bring MUs online according to load demand. To date, every dynamic variable recruitment study in the literature has considered homogeneous bundles containing MUs of equal size. However, natural mammalian muscle MUs are heterogeneous and primarily operate based on Henneman's size principle, which states that MUs are recruited from smallest to largest for a given task. Is it better for a FAM variable recruitment bundle to operate according to this principle, or are there other recruitment orders that result in better performance? What are the appropriate criteria for switching between recruitment states for these different recruitment orders? This paper seeks to answer these questions by performing two case studies exploring different bundle MU size distributions, analyzing the tradeoffs between tracking performance and energetics, and determining how these tradeoffs are affected by different MU recruitment order and recruitment state transition thresholds. The only difference between the two test cases is the overall force capacity (i.e. total size) of the bundle. For each test case, a Pareto frontier for different MU size distributions, recruitment orders, and recruitment state transition thresholds is constructed. The results show that there is a complex relationship between overall bundle size, MU size distributions, recruitment orders, and recruitment state transition thresholds corresponding to the best tradeoffs change along the Pareto frontier. Overall, these two case studies validate the use of Henneman's Size Principle as a variable recruitment strategy, but also demonstrate that it should not be the only variable recruitment method considered. They also motivate the need for a more complex variable recruitment scheme that dynamically changes the recruitment state transition threshold and recruitment order based on loading conditions and known system states, along with a co-design problem that optimizes total bundle size and MU size distribution.
在传统的液压机器人技术中,执行器的大小必须满足尽可能高的负载要求,这就导致在低力状态下工作时能量损失巨大。可变募集流体人工肌肉(FAM)束为这一问题提供了一种新颖的生物启发式解决方案。可变募集流体人工肌肉束分为单个人工肌肉单元,每个单元都有自己的控制阀,它采用开关控制方案,根据负载需求选择性地将人工肌肉单元联机。迄今为止,文献中的所有动态可变招募研究都考虑了包含相同大小 MU 的同质束。然而,自然哺乳动物的肌肉单元是异质的,主要根据海尼曼的大小原则运行,即从最小到最大招募肌肉单元。FAM 可变招募束是根据这一原则运行更好,还是有其他招募顺序能带来更好的性能?对于这些不同的招募顺序,在招募状态之间切换的适当标准是什么?本章试图通过两个案例研究来回答这些问题,这两个案例研究探索了不同的束 MU 大小分布,分析了跟踪性能和能量学之间的权衡,并确定了不同的 MU 招募顺序和招募状态转换阈值对这些权衡的影响。两个测试案例之间的唯一区别在于束的总体受力能力(即总大小)。针对每种测试案例,我们都构建了不同 MU 大小分布、招募顺序和招募状态转换阈值的帕累托前沿。结果表明,总体捆绑规模、MU 规模分布、招募顺序和招募状态转换阈值之间存在复杂的关系,对应于帕累托前沿的最佳折衷变化。总之,这两个案例研究验证了亨尼曼大小原则作为可变招募策略的有效性,但也表明它不应该是唯一可以考虑的方法。
{"title":"Investigation of the tradeoffs between tracking performance and energetics in heterogeneous variable recruitment fluidic artificial muscle bundles.","authors":"Nicholas Mazzoleni, Matthew Bryant","doi":"10.1088/1748-3190/ad649d","DOIUrl":"10.1088/1748-3190/ad649d","url":null,"abstract":"<p><p>In traditional hydraulic robotics, actuators must be sized for the highest possible load, resulting in significant energy losses when operating in lower force regimes. Variable recruitment fluidic artificial muscle (FAM) bundles offer a novel bio-inspired solution to this problem. Divided into individual MUs, each with its own control valve, a variable recruitment FAM bundle uses a switching control scheme to selectively bring MUs online according to load demand. To date, every dynamic variable recruitment study in the literature has considered homogeneous bundles containing MUs of equal size. However, natural mammalian muscle MUs are heterogeneous and primarily operate based on Henneman's size principle, which states that MUs are recruited from smallest to largest for a given task. Is it better for a FAM variable recruitment bundle to operate according to this principle, or are there other recruitment orders that result in better performance? What are the appropriate criteria for switching between recruitment states for these different recruitment orders? This paper seeks to answer these questions by performing two case studies exploring different bundle MU size distributions, analyzing the tradeoffs between tracking performance and energetics, and determining how these tradeoffs are affected by different MU recruitment order and recruitment state transition thresholds. The only difference between the two test cases is the overall force capacity (i.e. total size) of the bundle. For each test case, a Pareto frontier for different MU size distributions, recruitment orders, and recruitment state transition thresholds is constructed. The results show that there is a complex relationship between overall bundle size, MU size distributions, recruitment orders, and recruitment state transition thresholds corresponding to the best tradeoffs change along the Pareto frontier. Overall, these two case studies validate the use of Henneman's Size Principle as a variable recruitment strategy, but also demonstrate that it should not be the only variable recruitment method considered. They also motivate the need for a more complex variable recruitment scheme that dynamically changes the recruitment state transition threshold and recruitment order based on loading conditions and known system states, along with a co-design problem that optimizes total bundle size and MU size distribution.</p>","PeriodicalId":55377,"journal":{"name":"Bioinspiration & Biomimetics","volume":null,"pages":null},"PeriodicalIF":3.1,"publicationDate":"2024-07-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141635871","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"计算机科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-07-24DOI: 10.1088/1748-3190/ad61a8
Meng Yu, Xiang Cheng, Shigang Peng, Liangyu Zhao, Pengfei Wang
Tactile sensors play an important role when robots perform contact tasks, such as physical information collection, force or displacement control to avoid collision. For these manipulations, excessive contact may cause damage while poor contact cause information loss between the robotic end-effector and the objects. Inspired by skin structure and signal transmission method, this paper proposes a tactile sensing system based on the self-sensing soft pneumatic actuator (S-SPA) capable of providing tactile sensing capability for robots. Based on the adjustable height and compliance characteristics of the S-SPA, the contact process is safe and more tactile information can be collected. And to demonstrate the feasibility and advantage of this system, a robotic hand with S-SPAs could recognize different textures and stiffness of the objects by touching and pinching behaviours to collect physical information of the various objects under the positive work states of the S-SPA. The result shows the recognition accuracy of the fifteen texture plates reaches 99.4%, and the recognition accuracy of the four stiffness cuboids reaches 100%by training a KNN model. This safe and simple tactile sensing system with high recognition accuracies based on S-SPA shows great potential in robotic manipulations and is beneficial to applications in domestic and industrial fields.
{"title":"A tactile sensing system capable of recognizing objects based on bioinspired self-sensing soft pneumatic actuator.","authors":"Meng Yu, Xiang Cheng, Shigang Peng, Liangyu Zhao, Pengfei Wang","doi":"10.1088/1748-3190/ad61a8","DOIUrl":"10.1088/1748-3190/ad61a8","url":null,"abstract":"<p><p>Tactile sensors play an important role when robots perform contact tasks, such as physical information collection, force or displacement control to avoid collision. For these manipulations, excessive contact may cause damage while poor contact cause information loss between the robotic end-effector and the objects. Inspired by skin structure and signal transmission method, this paper proposes a tactile sensing system based on the self-sensing soft pneumatic actuator (S-SPA) capable of providing tactile sensing capability for robots. Based on the adjustable height and compliance characteristics of the S-SPA, the contact process is safe and more tactile information can be collected. And to demonstrate the feasibility and advantage of this system, a robotic hand with S-SPAs could recognize different textures and stiffness of the objects by touching and pinching behaviours to collect physical information of the various objects under the positive work states of the S-SPA. The result shows the recognition accuracy of the fifteen texture plates reaches 99.4%, and the recognition accuracy of the four stiffness cuboids reaches 100%by training a KNN model. This safe and simple tactile sensing system with high recognition accuracies based on S-SPA shows great potential in robotic manipulations and is beneficial to applications in domestic and industrial fields.</p>","PeriodicalId":55377,"journal":{"name":"Bioinspiration & Biomimetics","volume":null,"pages":null},"PeriodicalIF":3.1,"publicationDate":"2024-07-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141581615","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"计算机科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-07-23DOI: 10.1088/1748-3190/ad62cf
Jinsheng Zhao, Neng Xia, Li Zhang
In the early twenty-first century, extensive research has been conducted on geckos' ability to climb vertical walls with the advancement of microscopy technology. Unprecedented studies and developments have focused on the adhesion mechanism, structural design, preparation methods, and applications of bioinspired dry adhesives. Notably, strong adhesion that adheres to both the principles of contact splitting and stress uniform distribution has been discovered and proposed. The increasing popularity of flexible electronic skins, soft crawling robots, and smart assembly systems has made switchable adhesion properties essential for smart adhesives. These adhesives are designed to be programmable and switchable in response to external stimuli such as magnetic fields, thermal changes, electrical signals, light exposure as well as mechanical processes. This paper provides a comprehensive review of the development history of bioinspired dry adhesives from achieving strong adhesion to realizing switchable adhesion.
{"title":"A review of bioinspired dry adhesives: from achieving strong adhesion to realizing switchable adhesion.","authors":"Jinsheng Zhao, Neng Xia, Li Zhang","doi":"10.1088/1748-3190/ad62cf","DOIUrl":"10.1088/1748-3190/ad62cf","url":null,"abstract":"<p><p>In the early twenty-first century, extensive research has been conducted on geckos' ability to climb vertical walls with the advancement of microscopy technology. Unprecedented studies and developments have focused on the adhesion mechanism, structural design, preparation methods, and applications of bioinspired dry adhesives. Notably, strong adhesion that adheres to both the principles of contact splitting and stress uniform distribution has been discovered and proposed. The increasing popularity of flexible electronic skins, soft crawling robots, and smart assembly systems has made switchable adhesion properties essential for smart adhesives. These adhesives are designed to be programmable and switchable in response to external stimuli such as magnetic fields, thermal changes, electrical signals, light exposure as well as mechanical processes. This paper provides a comprehensive review of the development history of bioinspired dry adhesives from achieving strong adhesion to realizing switchable adhesion.</p>","PeriodicalId":55377,"journal":{"name":"Bioinspiration & Biomimetics","volume":null,"pages":null},"PeriodicalIF":3.1,"publicationDate":"2024-07-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141602209","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"计算机科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-07-23DOI: 10.1088/1748-3190/ad622d
Jinan Liu, Yiqiang Fu, Yifei Wu, Haihui Ruan
This work examines the acoustically actuated motions of artificial flagellated micro-swimmers (AFMSs) and compares the motility of these micro-swimmers with the predictions based on the corrected resistive force theory (RFT) and the bar-joint model proposed in our previous work. The key ingredient in the theory is the introduction of a correction factorKin drag coefficients to correct the conventional RFT so that the dynamics of an acoustically actuated AFMS with rectangular cross-sections can be accurately modeled. Experimentally, such AFMSs can be easily manufactured based on digital light processing of ultra-violet (UV)-curable resins. We first determined the viscoelastic properties of a UV-cured resin through dynamic mechanical analysis. In particular, the high-frequency storage moduli and loss factors were obtained based on the assumption of time-temperature superposition (TTS), which were then applied in theoretical calculations. Though the extrapolation based on the TTS implied the uncertainty of high-frequency material response and there is limited accuracy in determining head oscillation amplitude, the differences between the measured terminal velocities of the AFMSs and the predicted ones are less than 50%, which, to us, is well acceptable. These results indicate that the motions of acoustic AFMS can be predicted, and thus, designed, which pave the way for their long-awaited applications in targeted therapy.
{"title":"Propulsion mechanism of artificial flagellated micro-swimmers actuated by acoustic waves-theory and experimental verification.","authors":"Jinan Liu, Yiqiang Fu, Yifei Wu, Haihui Ruan","doi":"10.1088/1748-3190/ad622d","DOIUrl":"10.1088/1748-3190/ad622d","url":null,"abstract":"<p><p>This work examines the acoustically actuated motions of artificial flagellated micro-swimmers (AFMSs) and compares the motility of these micro-swimmers with the predictions based on the corrected resistive force theory (RFT) and the bar-joint model proposed in our previous work. The key ingredient in the theory is the introduction of a correction factor<i>K</i>in drag coefficients to correct the conventional RFT so that the dynamics of an acoustically actuated AFMS with rectangular cross-sections can be accurately modeled. Experimentally, such AFMSs can be easily manufactured based on digital light processing of ultra-violet (UV)-curable resins. We first determined the viscoelastic properties of a UV-cured resin through dynamic mechanical analysis. In particular, the high-frequency storage moduli and loss factors were obtained based on the assumption of time-temperature superposition (TTS), which were then applied in theoretical calculations. Though the extrapolation based on the TTS implied the uncertainty of high-frequency material response and there is limited accuracy in determining head oscillation amplitude, the differences between the measured terminal velocities of the AFMSs and the predicted ones are less than 50%, which, to us, is well acceptable. These results indicate that the motions of acoustic AFMS can be predicted, and thus, designed, which pave the way for their long-awaited applications in targeted therapy.</p>","PeriodicalId":55377,"journal":{"name":"Bioinspiration & Biomimetics","volume":null,"pages":null},"PeriodicalIF":3.1,"publicationDate":"2024-07-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141592150","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"计算机科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-07-15DOI: 10.1088/1748-3190/ad5ee7
Richard J Nash, Yaning Li
Inspired by the protective armors in nature, composites with asymmetric 3D articulated tiles attached to a soft layer are designed and fabricated via a multi-material 3D printer. The bending resistance of the new designs are characterized via three-point bending experiments. Bending rigidity, strength, and final deflection of the designs are quantified and compared when loaded in two different in-plane and two different out-of-plane directions. It is found that in general, the designs with articulated tiles show direction-dependent bending behaviors with significantly increased bending rigidity, strength, and deflection to final failure in certain loading directions, as is attributed to the asymmetric tile articulation (asymmetric about the mid-plane of tiles) and an interesting sliding-induced auxetic effect. Analytical, numerical, and experimental analyses are conducted to unveil the underlying mechanisms.
{"title":"Direction-dependent bending resistance of 3D printed bio-inspired composites with asymmetric 3D articulated tiles.","authors":"Richard J Nash, Yaning Li","doi":"10.1088/1748-3190/ad5ee7","DOIUrl":"10.1088/1748-3190/ad5ee7","url":null,"abstract":"<p><p>Inspired by the protective armors in nature, composites with asymmetric 3D articulated tiles attached to a soft layer are designed and fabricated via a multi-material 3D printer. The bending resistance of the new designs are characterized via three-point bending experiments. Bending rigidity, strength, and final deflection of the designs are quantified and compared when loaded in two different in-plane and two different out-of-plane directions. It is found that in general, the designs with articulated tiles show direction-dependent bending behaviors with significantly increased bending rigidity, strength, and deflection to final failure in certain loading directions, as is attributed to the asymmetric tile articulation (asymmetric about the mid-plane of tiles) and an interesting sliding-induced auxetic effect. Analytical, numerical, and experimental analyses are conducted to unveil the underlying mechanisms.</p>","PeriodicalId":55377,"journal":{"name":"Bioinspiration & Biomimetics","volume":null,"pages":null},"PeriodicalIF":3.1,"publicationDate":"2024-07-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141499698","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"计算机科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-07-15DOI: 10.1088/1748-3190/ad5c25
Stan R R Baeten, Ana Kochovski, Jovana Jovanova, Aimée Sakes
This review explores the present knowledge of the unique properties of shark skin and possible applications of its functionalities, including drag reduction and swimming efficiency. Tooth-like denticles, with varied morphologies, sizes, and densities across the shark's body, significantly influence the flow and interaction of fluids. Examining dermal denticle morphology, this study unveils the functional properties of real shark skin, including mechanical properties such as stiffness, stress-strain characteristics, and denticle density's impact on tensile properties. The adaptive capabilities of the Mako shark scales, especially in high-speed swimming, are explored, emphasizing their passive flow-actuated dynamic micro-roughness. This research contains an overview of various studies on real shark skin, categorizing them into skin properties, morphology, and hydrodynamics. The paper extends exploration into industrial applications, detailing fabrication techniques and potential uses in vessels, aircraft, and water pipes for friction reduction. Three manufacturing approaches, bio-replicated forming, direct fabrication, and indirect manufacturing, are examined, with 3D printing and photoconfiguration technology emerging as promising alternatives. Investigations into the mechanical properties of shark skin fabrics reveal the impact of denticle size on tensile strength, stress, and strain. Beyond drag reduction, the study highlights the shark skin's role in enhancing thrust and lift during locomotion. The paper identifies future research directions, emphasizing live shark testing and developing synthetic skin with the help of 3D printing incorporating the bristling effect.
{"title":"Characterization of shark skin properties and biomimetic replication.","authors":"Stan R R Baeten, Ana Kochovski, Jovana Jovanova, Aimée Sakes","doi":"10.1088/1748-3190/ad5c25","DOIUrl":"10.1088/1748-3190/ad5c25","url":null,"abstract":"<p><p>This review explores the present knowledge of the unique properties of shark skin and possible applications of its functionalities, including drag reduction and swimming efficiency. Tooth-like denticles, with varied morphologies, sizes, and densities across the shark's body, significantly influence the flow and interaction of fluids. Examining dermal denticle morphology, this study unveils the functional properties of real shark skin, including mechanical properties such as stiffness, stress-strain characteristics, and denticle density's impact on tensile properties. The adaptive capabilities of the Mako shark scales, especially in high-speed swimming, are explored, emphasizing their passive flow-actuated dynamic micro-roughness. This research contains an overview of various studies on real shark skin, categorizing them into skin properties, morphology, and hydrodynamics. The paper extends exploration into industrial applications, detailing fabrication techniques and potential uses in vessels, aircraft, and water pipes for friction reduction. Three manufacturing approaches, bio-replicated forming, direct fabrication, and indirect manufacturing, are examined, with 3D printing and photoconfiguration technology emerging as promising alternatives. Investigations into the mechanical properties of shark skin fabrics reveal the impact of denticle size on tensile strength, stress, and strain. Beyond drag reduction, the study highlights the shark skin's role in enhancing thrust and lift during locomotion. The paper identifies future research directions, emphasizing live shark testing and developing synthetic skin with the help of 3D printing incorporating the bristling effect.</p>","PeriodicalId":55377,"journal":{"name":"Bioinspiration & Biomimetics","volume":null,"pages":null},"PeriodicalIF":3.1,"publicationDate":"2024-07-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141460889","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"计算机科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}