Biomimetics

35 pages, 2121 KB

Open AccessArticle

An Evolutionary-Algorithm-Driven Efficient Temporal Convolutional Network for Radar Image Extrapolation

by Peiyang Wei, Changyuan Fan, Yuyan Wang, Tianlong Li, Jianhong Gan, Can Hu and Zhibin Li

Biomimetics 2026, 11(2), 122; https://doi.org/10.3390/biomimetics11020122 - 6 Feb 2026

Radar image extrapolation serves as a fundamental methodology in meteorological forecasting, facilitating precise short-term weather prediction through spatiotemporal sequence analysis. Conventional approaches remain constrained by progressive image degradation and artifacts, substantially limiting operational forecasting reliability. This research introduces E-HEOA—an enhanced deep learning architecture [...] Read more.

Radar image extrapolation serves as a fundamental methodology in meteorological forecasting, facilitating precise short-term weather prediction through spatiotemporal sequence analysis. Conventional approaches remain constrained by progressive image degradation and artifacts, substantially limiting operational forecasting reliability. This research introduces E-HEOA—an enhanced deep learning architecture with integrated hyperparameter optimization. Our framework incorporates two fundamental innovations: (a) a hybrid metaheuristic optimizer merging a Gaussian-mutated ESOA and Cauchy-mutated HEOA for autonomous learning rate and dropout optimization and (b) embedded ConvLSTM2D modules for enhanced spatiotemporal feature preservation. Experimental validation on 170,000 radar echo samples demonstrates superior performance, demonstrating considerable enhancement in almost all aspects relative to the baseline model while establishing new state-of-the-art benchmarks in prediction fidelity, convergence efficiency, and structural similarity metrics. Full article

(This article belongs to the Special Issue Bio-Inspired Data-Driven Methods and Their Applications in Engineering Control, Optimization and AI)

37 pages, 3961 KB

Open AccessArticle

Theoretical Dynamics Modeling of Pitch Motion and Obstacle-Crossing Capability Analysis for Articulated Tracked Vehicles Based on Myriapod Locomotion Mechanism

by Ningyi Li, Xixia Liu, Hongqian Chen, Yu Zhang and Shaoliang Zhang

Biomimetics 2026, 11(2), 121; https://doi.org/10.3390/biomimetics11020121 - 6 Feb 2026

Abstract

Myriapods achieve remarkable obstacle-crossing capability through inter-segment pitch adjustment and coordinated anterior–posterior propulsion, providing valuable biomimetic inspiration for engineering design. Articulated tracked vehicles, connecting front and rear units via pitch mechanisms, exhibit functional similarity to myriapod body segments. This study develops a comprehensive [...] Read more.

Myriapods achieve remarkable obstacle-crossing capability through inter-segment pitch adjustment and coordinated anterior–posterior propulsion, providing valuable biomimetic inspiration for engineering design. Articulated tracked vehicles, connecting front and rear units via pitch mechanisms, exhibit functional similarity to myriapod body segments. This study develops a comprehensive dynamic model for articulated tracked vehicle pitch motion to reveal its biomimetic connection with myriapod locomotion. A quadratic-function-based non-uniform track–ground contact pressure distribution method with zero-gradient boundary conditions is proposed, effectively eliminating the non-physical negative pressure issue inherent in traditional assumptions. Systematic analyses reveal that the front unit provides primary traction under pitch-up conditions, forming a front-pulling-rear driving mode, while the rear unit dominates under pitch-down and acceleration conditions, forming a rear-pushing-front driving mode. Through pitch attitude adjustment, the maximum surmountable vertical-wall height increased from 263 to 593 mm, representing a 125.45% improvement. This traction distribution pattern closely matches the anterior-guidance and posterior-propulsion mechanism observed in myriapod locomotion. This study quantitatively validates the functional analogy between articulated tracked vehicle pitch dynamics and myriapod inter-segment coordination, providing theoretical foundations for bio-inspired tracked vehicle design. Full article

(This article belongs to the Special Issue Bionics in Engineering Practice: Innovations and Applications)

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24 pages, 152792 KB

Open AccessArticle

Crashworthiness Analysis of Bio-Inspired Multi-Cell Concave Tubes

by Xiaolin Deng, Jinjin Huang and Jialiang Xie

Biomimetics 2026, 11(2), 120; https://doi.org/10.3390/biomimetics11020120 - 6 Feb 2026

Abstract

This study presents a novel bio-inspired multi-cell concave tube (BMCT) inspired by the biomimicry of horse tail grass plants. Following the simulation validation, a comprehensive investigation into the crashworthiness of this structure under axial impact was conducted. Concurrently, both experimental and theoretical analyses [...] Read more.

This study presents a novel bio-inspired multi-cell concave tube (BMCT) inspired by the biomimicry of horse tail grass plants. Following the simulation validation, a comprehensive investigation into the crashworthiness of this structure under axial impact was conducted. Concurrently, both experimental and theoretical analyses were employed to substantiate the reliability of the simulation data. Comparative results concerning crashworthiness indicate that, relative to other structures, the BMCT maintains a relatively constant initial peak force while simultaneously enhancing energy absorption capacity at equivalent mass. Specifically, when compared to corresponding hierarchical multi-cell tubes with the same number of cells, the BMCT exhibits a 41.04% increase in crush force efficiency (CFE) while preserving a relatively unchanged initial peak crushing force (IPCF). Additionally, variations in hierarchical levels yield a 21.22% increase in CFE at the same mass. Full article

(This article belongs to the Section Biomimetics of Materials and Structures)

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30 pages, 4371 KB

Open AccessSystematic Review

Standardizing TEER Measurements in Blood-Brain Barrier-on-Chip Systems: A Systematic Review of Electrode Designs and Configurations

by Nazanin Ghane, Reza Jafari and Naser Valipour Motlagh

Biomimetics 2026, 11(2), 119; https://doi.org/10.3390/biomimetics11020119 - 5 Feb 2026

Abstract

The blood-brain barrier (BBB) is one of the most selective physiological interfaces in the human body. Transendothelial electrical resistance (TEER) has become a widely adopted quantitative metric for assessing its in vitro structural and functional integrity. Although TEER measurements are routinely incorporated into [...] Read more.

The blood-brain barrier (BBB) is one of the most selective physiological interfaces in the human body. Transendothelial electrical resistance (TEER) has become a widely adopted quantitative metric for assessing its in vitro structural and functional integrity. Although TEER measurements are routinely incorporated into BBB-on-chips, the absence of harmonized electrode architectures, measurement settings, and reporting standards continues to undermine reproducibility and translational reliability among laboratories. This systematic review provides the first comprehensive classification and critical comparison of electrode configurations used for TEER assessment, specifically within BBB-on-chip systems. Eligible studies were analyzed and categorized according to electrode design, fabrication method, integration strategy, and operational constraints. We critically evaluated six principal electrode architectures, highlighting their performance trade-offs in terms of uniformity of current distribution, long-term stability, scalability, and compatibility with dynamic shear conditions. Furthermore, we propose a bioinspired TEER reporting framework that consolidates essential metadata, including electrode specification, temperature control, viscosity effects, and blank resistance correction. Our analysis proposes screen-printed and hybrid silver-indium tin oxide (ITO) electrodes as promising candidates for next-generation BBB platforms. Moreover, our review provides a structured roadmap for standardizing TEER electrode design and reporting practices to facilitate interlaboratory consistency and accelerate the adoption of BBB-on-chip systems as truly biomimetic platforms for predictive neuropharmacological workflows. Full article

(This article belongs to the Section Biomimetic Design, Constructions and Devices)

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25 pages, 5479 KB

Open AccessArticle

Design and Performance Evaluation of Biomimetic Suction Cups Inspired by the Abalone Muscular Foot

by Lingmi Wu, Yi Fang and Guoniu Zhu

Biomimetics 2026, 11(2), 118; https://doi.org/10.3390/biomimetics11020118 - 5 Feb 2026

Abstract

This study addresses the limited adsorption efficiency of traditional vacuum suction cups used in applications such as unmanned aerial vehicles (UAVs) and robotic systems. Inspired by the adhesion mechanism of the abalone muscular foot, we propose a novel suction cup design. The design [...] Read more.

This study addresses the limited adsorption efficiency of traditional vacuum suction cups used in applications such as unmanned aerial vehicles (UAVs) and robotic systems. Inspired by the adhesion mechanism of the abalone muscular foot, we propose a novel suction cup design. The design incorporates optimization of the groove geometry, groove distribution, and the positioning of the sealing ring. To assess the mechanical performance of these designs, finite element analysis (FEA) is employed. A prototype exhibiting the most promising simulation results is fabricated and subjected to tensile testing. The experimental results show strong agreement with the simulation outcomes, thereby validating the accuracy and reliability of the FEA. The biomimetic suction cup demonstrates superior adsorption performance compared to the baseline design. Specifically, the maximum von Mises stress is reduced by 5.9%, the maximum pressure is increased by 498%, and the maximum frictional stress rises by 498%. Moreover, the maximum sliding distance is reduced by 38%, while the maximum total circumferential deformation is increased by 21%. This innovative design enhances the stress distribution across the bottom surface of the suction cup, mitigates inward edge contraction, and delays the communication between the inner cavity and the external environment, thereby improving the overall adsorption efficiency of the suction cup. Full article

(This article belongs to the Special Issue Recent Advances in Bioinspired Robot and Intelligent Systems)

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17 pages, 1180 KB

Open AccessArticle

A Pilot Three-Dimensional Evaluation of Acetabular Bony Coverage After Modified Spitzy Shelf Acetabuloplasty

by Fumito Kobayashi, Takehito Hananouchi, Kenichi Oe, Shohei Sogawa, Tomohisa Nakamura and Takanori Saito

Biomimetics 2026, 11(2), 117; https://doi.org/10.3390/biomimetics11020117 - 5 Feb 2026

Abstract

Modified Spitzy shelf acetabuloplasty is a joint-preserving surgical procedure for acetabular dysplasia that aims to enhance bony coverage of the hip joint. Although prior studies have primarily relied on two-dimensional (2D) radiographic evaluations, comprehensive three-dimensional (3D) assessments remain limited. The purpose of this [...] Read more.

Modified Spitzy shelf acetabuloplasty is a joint-preserving surgical procedure for acetabular dysplasia that aims to enhance bony coverage of the hip joint. Although prior studies have primarily relied on two-dimensional (2D) radiographic evaluations, comprehensive three-dimensional (3D) assessments remain limited. The purpose of this retrospective study was to evaluate changes quantitatively in acetabular coverage following modified Spitzy shelf acetabuloplasty using 3D models reconstructed from computed tomography (CT) images. We retrospectively analyzed 11 hips in 11 patients who underwent staged bilateral modified Spitzy shelf acetabuloplasty. Preoperative and postoperative CT data were used to construct 3D pelvic models, which were registered using anatomical landmarks. Bone graft dimensions, insertion angle, and placement location were evaluated. Acetabular sector angles (ASA), representing circumferential coverage of the femoral head, were measured at 15° intervals on the functional pelvic plane and the anterior pelvic plane. The mean bone graft dimensions were 26.3 ± 3 mm (anteroposterior length) and 12.7 ± 2.7 mm (mediolateral length), providing coverage of 49.5° ± 9.1°. Postoperative ASA increased significantly from 34.5° to 60° on the functional pelvic plane and from 0° to 45° on the anterior pelvic plane (both p < 0.05). 3D analysis demonstrated that modified Spitzy shelf acetabuloplasty effectively enhanced anterosuperior acetabular bony coverage. Although this is a report of a few cases (11 hips), the above findings highlight the value of 3D evaluation in identifying postoperative changes that may not be detected using conventional 2D assessments. Also, further research analyzing the three-dimensional bone graft model revealed in this study may help inform the development of a more ideal biomimetic approach, not only in terms of shape but also function. Full article

(This article belongs to the Special Issue Advancements in 3D Printing and Additive Manufacturing for Orthopedic Applications)

18 pages, 2461 KB

Open AccessArticle

Tissue Regeneration on Implantoplasty-Treated Implants Using a Citric Acid–Collagen–Magnesium-Based Solution: An In Vitro and In Vivo Study

by Samuel Oliván, Pedro Fernández-Domínguez, Javier Gil and Manuel Fernández-Domínguez

Biomimetics 2026, 11(2), 116; https://doi.org/10.3390/biomimetics11020116 - 4 Feb 2026

Abstract

Peri-implantitis is an inflammatory disease caused by bacterial colonization that leads to progressive bone loss around dental implants. Implantoplasty is widely used for biofilm removal; however, it alters the titanium surface, generating particle release and impairing surface properties. This study evaluated whether a [...] Read more.

Peri-implantitis is an inflammatory disease caused by bacterial colonization that leads to progressive bone loss around dental implants. Implantoplasty is widely used for biofilm removal; however, it alters the titanium surface, generating particle release and impairing surface properties. This study evaluated whether a citric acid-based solution supplemented with collagen and magnesium cations could enhance hard and soft tissue regeneration following implantoplasty. Three surfaces were analyzed: physiological saline (Ctr), 25% citric acid (AC), and citric acid with collagen and magnesium nitrate hexahydrate (AC500/Mg). Surface roughness and wettability were assessed on titanium discs. Cytocompatibility, cell adhesion, and proliferation were evaluated using fibroblasts and osteoblasts up to 21 days, and mineralization was analyzed by alkaline phosphatase. In vivo studies were conducted in New Zealand rabbits with implants placed in the femur and muscle tissue. Surface roughness did not differ among treatments, while wettability significantly increased with citric acid-based solutions. All treatments showed good cytocompatibility. AC500/Mg significantly enhanced cell adhesion, proliferation, and osteoblast mineralization, showing threefold higher activity than controls at 21 days. In vivo, AC500/Mg exhibited greater bone contact (67%) and direct muscle integration, whereas AC and Ctr showed lower bone contact and fibrotic encapsulation. These results indicate that AC500/Mg improves soft and hard tissue responses without altering roughness, suggesting its potential as a regenerative strategy following implantoplasty. Full article

(This article belongs to the Special Issue Application of Biomimetic Materials in Regenerative and Restorative Dentistry)

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21 pages, 3762 KB

Open AccessArticle

Motion Strategy Generation Based on Multimodal Motion Primitives and Reinforcement Learning Imitation for Quadruped Robots

by Qin Zhang, Guanglei Li, Benhang Liu, Chenxi Li, Chuanle Zhu and Hui Chai

Biomimetics 2026, 11(2), 115; https://doi.org/10.3390/biomimetics11020115 - 4 Feb 2026

Abstract

With the advancement of task-oriented reinforcement learning (RL), the capability of quadruped robots for motion generation and complex task completion has significantly improved. However, current control strategies require extensive domain expertise and time-consuming design processes to acquire operational skills and achieve multi-task motion [...] Read more.

With the advancement of task-oriented reinforcement learning (RL), the capability of quadruped robots for motion generation and complex task completion has significantly improved. However, current control strategies require extensive domain expertise and time-consuming design processes to acquire operational skills and achieve multi-task motion control, often failing to effectively manage complex behaviors composed of multiple coordinated actions. To address these limitations, this paper proposes a motion policy generation method for quadruped robots based on multimodal motion primitives and imitation learning. A multimodal motion library was constructed using 3D engine motion design, motion capture data retargeting, and trajectory planning. A temporal domain-based behavior planner was designed to combine these primitives and generate complex behaviors. We developed a RL-based imitation learning training framework to achieve precise trajectory tracking and rapid policy deployment, ensuring the effective application of actions/behaviors on the quadruped platform. Simulation and physical experiments conducted on the Lite3 quadruped robot validated the efficacy of the proposed approach, offering a new paradigm for the deployment and development of motion strategies for quadruped robots. Full article

(This article belongs to the Section Locomotion and Bioinspired Robotics)

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18 pages, 4814 KB

Open AccessFeature PaperArticle

Natural Nacre-Derived Biomimetic Materials for In Vivo Bone Regeneration

by Pierre-Yves Collart-Dutilleul, Naveen Fatima, Richard Younes, Frédéric Cuisinier, Véronique Barragan-Montero and Alban Desoutter

Biomimetics 2026, 11(2), 114; https://doi.org/10.3390/biomimetics11020114 - 4 Feb 2026

Abstract

Bone regeneration in critical-size defects requires biomaterials that provide both structural support and appropriate osteoinductive cues. Natural nacre contains an organic matrix rich in acidic macromolecules with reported osteogenic activity; however, its in vivo regenerative potential remains insufficiently explored. This study evaluated the [...] Read more.

Bone regeneration in critical-size defects requires biomaterials that provide both structural support and appropriate osteoinductive cues. Natural nacre contains an organic matrix rich in acidic macromolecules with reported osteogenic activity; however, its in vivo regenerative potential remains insufficiently explored. This study evaluated the bone regenerative capacity of nacre-derived materials alone and combined with oxidized porous silicon microparticles (pSi-MP), a bioactive material known to release silicic acid and support mineralized tissue formation. Critical-size defects were created in four caudal vertebrae of Wistar rats and filled with nacre, pSi-MP, a nacre–pSi composite, or left empty. After 60 days, bone formation was assessed using micro-computed tomography and non-decalcified histology. Empty defects failed to regenerate, whereas nacre and pSi-MP individually promoted partial mineralized tissue deposition. The nacre–pSi composite produced the most extensive repair, showing near-complete defect bridging, higher bone mineral density, and seamless integration of particles within newly formed bone. No inflammation or adverse reactions were observed, and osteoid deposition occurred directly on material surfaces. These findings demonstrate that nacre-derived materials exert intrinsic osteogenic effects in vivo and that combining nacre with porous silicon yields a synergistic response that significantly enhances bone regeneration. The composite represents a promising candidate for future bone repair strategies. Full article

(This article belongs to the Special Issue Biomimetic Strategies to Enhance Bone Tissue Healing, Remodeling and Regeneration: 2nd Edition)

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22 pages, 8460 KB

Open AccessArticle

Design and Implementation of a Three-Segment Tendon-Driven Continuum Robot with Variable Stiffness for Manipulation in Confined Spaces

by Zhixuan Weng, Liansen Sha, Yufei Chen, Bingyu Fan, Lan Li and Bin Liu

Biomimetics 2026, 11(2), 113; https://doi.org/10.3390/biomimetics11020113 - 4 Feb 2026

Abstract

Continuum robots (CRs) exhibit high compliance and environmental adaptability in confined, tortuous spaces, yet their inherent low stiffness and load capacity limit performance in precise positioning and stable support tasks. To solve the “soft-rigid” paradox, this study proposes and implements a three-segment tendon-driven [...] Read more.

Continuum robots (CRs) exhibit high compliance and environmental adaptability in confined, tortuous spaces, yet their inherent low stiffness and load capacity limit performance in precise positioning and stable support tasks. To solve the “soft-rigid” paradox, this study proposes and implements a three-segment tendon-driven variable-stiffness CR. Structurally, a segmented constant-curvature model directs the optimization of grid skeletons and notch parameters, enhancing bending consistency and motion predictability. Elongated flat airbag actuators, arranged in annular arrays, enable segment-level stiffness switching through the enhancement of surface properties like axial constraints and friction amplification. A time-sharing drive strategy decouples multi-segment coupling into sequential single-segment subproblems, reducing drivers and kinematic complexity while maintaining dexterity. Experimental results demonstrate that flexible-mode joints maintain near-constant curvature with stable motion (average end-effector trajectory error < 0.9 mm), and in rigid mode, stiffness increases by a factor of 5.77 (rated load: 4.0 N). Shape-locking disturbances during transitions are confined to millimeter levels (remote offset < 1.32 mm), with successful traversal of J/U/S-shaped and irregular paths confirmed in pipeline tests. This work introduces a practical, scalable system for designing variable-stiffness structures and enabling low-complexity multi-segment control, offering valuable insights for minimally invasive devices and industrial endoscopy in confined spaces. Full article

(This article belongs to the Special Issue Advancements in Soft and Continuum Robotics for Medical Applications: Design, Control and Clinical Integration)

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11 pages, 1018 KB

Open AccessArticle

Perceptual Design and Evaluation of a Forearm-Based Vibrotactile Interface for Transfemoral Prosthetic Feedback

by Mohammadmahdi Karimi, Sigurður Brynjólfsson, Kristín Briem, Árni Kristjánsson and Runar Unnthorsson

Biomimetics 2026, 11(2), 112; https://doi.org/10.3390/biomimetics11020112 - 4 Feb 2026

Abstract

The lack of reliable sensory input from prosthetic limbs limits transfemoral amputees’ ability to perceive limb movement without visual monitoring. This study evaluated design parameters of a proposed forearm-based vibrotactile system in a pre-clinical, design-level perceptual evaluation, conveying prosthetic joint positions through patterned [...] Read more.

The lack of reliable sensory input from prosthetic limbs limits transfemoral amputees’ ability to perceive limb movement without visual monitoring. This study evaluated design parameters of a proposed forearm-based vibrotactile system in a pre-clinical, design-level perceptual evaluation, conveying prosthetic joint positions through patterned vibrations to provide non-invasive proprioceptive feedback. Healthy participants completed two experiments assessing detection of tactile cues from dual-actuator bands on the wrist and elbow representing assumed ankle and knee positions. The effects of temporal structuring (sequential vs. simultaneous stimulation), actuator configuration, amplitude and frequency settings, and signal duration on response accuracy were examined. Sequential vibrations produced significantly higher recognition accuracy than simultaneous presentation (72.4% vs. 42.7%, p < 0.001) in a variety of vibration signal parameter values. Actuator placement also influenced performance: simultaneous stimulation on opposite forearm sides yielded significantly lower accuracy (p < 0.001) than same-side configurations, whereas this directional effect was not significant for sequential presentation. Accuracy did not differ significantly between equal and unequal amplitude or frequency levels across actuators. Longer stimulus durations improved accuracy, increasing from 82.3% at 60 ms to 92.5% at 240 ms, though the results indicated a saturation point, suggesting an optimal temporal window. These findings inform the design of forearm-based sensory feedback systems for improved prosthetic limb control. Full article

(This article belongs to the Special Issue Wearable Computing Devices and Their Interactive Technologies)

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19 pages, 1809 KB

Open AccessArticle

Comprehensive Learning-Enhanced Educational Competition Optimizer for Numerical Optimization and Reservoir Production Optimization

by Shuaizhen Li and Jinxiong Luo

Biomimetics 2026, 11(2), 111; https://doi.org/10.3390/biomimetics11020111 - 3 Feb 2026

Abstract

The performance of metaheuristic algorithms in solving high-dimensional, non-convex optimization problems is intricately linked to the balance between global exploration and local exploitation. Inspired by biomimetic principles of swarm intelligence, this study evaluates the Educational Competition Optimizer (ECO), a human learning-inspired metaheuristic, and [...] Read more.

The performance of metaheuristic algorithms in solving high-dimensional, non-convex optimization problems is intricately linked to the balance between global exploration and local exploitation. Inspired by biomimetic principles of swarm intelligence, this study evaluates the Educational Competition Optimizer (ECO), a human learning-inspired metaheuristic, and addresses its vulnerability to rapid population homogenization and premature convergence in complex landscapes. To bridge the gap between rigid hierarchical competition and flexible biological cooperation, we propose the Comprehensive Learning-Enhanced Educational Competition Optimizer (CL-ECO), which introduces a dimension-wise multi-exemplar social learning mechanism to the ECO framework. Analogous to cooperative information sharing in animal swarms, CL-ECO reconstructs search trajectories by learning from different peers across decision variables, thereby promoting population diversity and adaptive exploration. Rigorous validation on the CEC 2017 benchmark suite demonstrates that CL-ECO achieves statistically superior convergence accuracy and robustness compared to seven state-of-the-art algorithms, securing the top Friedman rank (1.5862). Furthermore, the practical utility of CL-ECO is substantiated through a complex reservoir production optimization case study, where it outperforms the baseline algorithm in NPV maximization, proving its capability in managing complex, real-world engineering constraints. Full article

(This article belongs to the Special Issue Bio-Inspired Intelligent Computation for Optimisation in Business and Engineering Applications)

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46 pages, 4420 KB

Open AccessArticle

EBBO: A Biomimetically Enhanced Optimization Algorithm with Multi-Stage Cooperation for Complex Engineering Applications

by Xuemei Zhu, Haoyu Cai, Shirong Li and Wei Peng

Biomimetics 2026, 11(2), 110; https://doi.org/10.3390/biomimetics11020110 - 3 Feb 2026

Abstract

This study proposes Enhanced Beaver Behavior Optimizer (EBBO) to overcome the original BBO algorithm’s limitations in handling complex optimization problems. EBBO integrates a three-phase cooperative framework, incorporating adaptive mutation, dynamic opposition-based learning, and an risk-aware decision strategy inspired by simulated annealing. Comprehensive evaluations [...] Read more.

This study proposes Enhanced Beaver Behavior Optimizer (EBBO) to overcome the original BBO algorithm’s limitations in handling complex optimization problems. EBBO integrates a three-phase cooperative framework, incorporating adaptive mutation, dynamic opposition-based learning, and an risk-aware decision strategy inspired by simulated annealing. Comprehensive evaluations on the CEC 2017 and CEC 2020 benchmark suites demonstrate that EBBO significantly outperforms nine widely used algorithms (e.g., BBO, FATA, DE) in convergence accuracy, stability, and robustness, especially for high-dimensional and multimodal functions. EBBO achieves average objective value reductions of 15–50% and standard deviation reductions of 30–70% compared to the original BBO, with Wilcoxon rank-sum tests confirming statistical significance across most functions. When applied to three classical engineering design problems—step-cone pulley, pressure vessel, three-bar truss optimization, and 3D UAV path planning—EBBO consistently achieved the best or near-optimal solutions while satisfying all nonlinear constraints. The results confirm that EBBO effectively balances exploration and exploitation, offering a reliable and efficient approach for solving complex constrained optimization challenges in both benchmark and real-world engineering contexts. Full article

(This article belongs to the Section Biological Optimisation and Management)

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26 pages, 9885 KB

Open AccessArticle

Hybrid LQR-H₂ Control of a Kestrel-Based Ornithopter with a Nature-Inspired Flow Control Device for Gust Mitigation

by Saddam Hussain, Ali Hennache, Nouman Abbasi and Dajun Xu

Biomimetics 2026, 11(2), 109; https://doi.org/10.3390/biomimetics11020109 - 3 Feb 2026

Abstract

Unsteady atmospheric disturbances significantly compromise the stability of ornithopters, necessitating advanced turbulence-mitigation strategies. In contrast, natural flyers display remarkable aerodynamic adaptability through dynamic flow-control mechanisms such as covert feathers, enabling stability across unsteady flow regimes. Drawing inspiration from this biological phenomenon, this study [...] Read more.

Unsteady atmospheric disturbances significantly compromise the stability of ornithopters, necessitating advanced turbulence-mitigation strategies. In contrast, natural flyers display remarkable aerodynamic adaptability through dynamic flow-control mechanisms such as covert feathers, enabling stability across unsteady flow regimes. Drawing inspiration from this biological phenomenon, this study presents the modeling and hybrid control of a kestrel-based ornithopter equipped with a Nature-Inspired Flow Control Device (NFCD) that replicates the adaptive feather deployment mechanism observed in kestrels. A reduced-order multibody bond-graph model (BGM) of the full ornithopter is developed, incorporating the main body, propulsion system, rigid wings, and the NFCD subsystem. The model captures key fluid-structure-interaction (FSI) effects between morphing feathers and surrounding airflow. A Linear Quadratic Regulator (LQR) ensures optimal performance under nominal gust conditions (≤3 m/s), while an H₂ controller activates during high-intensity gusts (≥4 m/s) to enhance disturbance rejection through electromechanical feather actuation. A gain-scheduled transition is employed in the intermediate gust range (3–4 m/s) to ensure a smooth transition between controllers. Simulations indicate up to 70% reduction in gust-induced oscillations and 32% gust-mitigation efficiency, achieved through feather actuation in the NFCD combined with hybrid control, stabilizing the ornithopter in less than 1.4 s under higher gust conditions. The close correspondence between simulated responses and previously reported findings validates the proposed approach. Overall, by merging biomimetic aerodynamics, nature-inspired flow control, and advanced control design, the LQR-H₂ governed NFCD provides a promising pathway toward gust-tolerant ornithopters capable of resilient and stable flight in unsteady atmospheric environments. Full article

(This article belongs to the Special Issue Bioinspired Aerodynamic-Fluidic Design)

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11 pages, 1498 KB

Open AccessArticle

In Vitro Mechanical Study of Three-Dimensional Printed Invisible Dental Aligners for Crowded Dentition Problems: A Patient-Specific Study

by Zelafy Reynosa, Hong-Seng Gan and Muhammad Hanif Ramlee

Biomimetics 2026, 11(2), 108; https://doi.org/10.3390/biomimetics11020108 - 3 Feb 2026

Abstract

Clear aligners are a popular alternative to fixed orthodontic appliances; however, technical data on the optimal final aligner shell thickness for directly printed aligners remain limited. This in vitro experimental pilot study evaluated the mechanical response of patient-specific, directly 3D-printed aligners of four [...] Read more.

Clear aligners are a popular alternative to fixed orthodontic appliances; however, technical data on the optimal final aligner shell thickness for directly printed aligners remain limited. This in vitro experimental pilot study evaluated the mechanical response of patient-specific, directly 3D-printed aligners of four nominal shell thicknesses (0.04, 0.06, 0.08, and 0.10 mm) fabricated from BioMed Clear resin. A single subject with dental crowding was scanned and a set of aligner shells was designed and printed (n = 3 per thickness). Compressive tests up to 1000 N were performed and compressive extension (mm) recorded; group means ± SD were compared by means of one-way ANOVA. No statistically significant differences in compressive extension were found among the four thickness groups (ANOVA, F(3,8) = 2.242, p = 0.161). The 0.08 mm group showed a lower mean compressive extension in this dataset, but the difference did not reach statistical significance; given the small sample size and single-subject nature of the study, this result should be considered exploratory. This recent study clarifies printing and post-processing parameters and highlights limitations and directions for future work. Full article

(This article belongs to the Section Development of Biomimetic Methodology)

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23 pages, 755 KB

Open AccessReview

Dental Erosion Management: From Remineralization to Emerging Regenerative Approaches—A Narrative Review

by Ruvienath Daham Weerasinghe Rajapaksa, Yu-Ching Wang, Yong Chen Chin, Kevin Jang, Abdala Abdal-hay, Sašo Ivanovski and Sandleen Feroz

Biomimetics 2026, 11(2), 107; https://doi.org/10.3390/biomimetics11020107 - 3 Feb 2026

Abstract

Dental erosion has emerged as a significant modern oral health problem, characterized by the chemical dissolution of tooth structure resulting from frequent exposure to intrinsic or extrinsic acids. With a high global prevalence ranging from 30% to 50% in children and 20% to [...] Read more.

Dental erosion has emerged as a significant modern oral health problem, characterized by the chemical dissolution of tooth structure resulting from frequent exposure to intrinsic or extrinsic acids. With a high global prevalence ranging from 30% to 50% in children and 20% to 40% in adults, its management is a clinical priority to prevent long-term complications like dentine hypersensitivity and functional impairment. This review outlines the multifactorial etiology of erosion, encompassing dietary acids, gastroesophageal reflux, and reduced salivary flow. The historical context of oral care is explored, leading to a discussion on contemporary management strategies centered on remineralization. Fluoride ions play a crucial role by inhibiting demineralization, facilitating the formation of acid-resistant fluorapatite, and exerting antibacterial effects. A major focus is placed on advanced biomimetic, calcium phosphate-based topical agents such as Casein Phosphopeptide–Amorphous Calcium Phosphate (CPP-ACP), functionalized Tricalcium Phosphate (fTCP), and Hydroxyapatite (HAP), which effectively replenish lost minerals. The review further explores innovative methods, such as laser-assisted and electrically enhanced remineralization. Finally, it outlines next-generation regenerative strategies, including self-assembling peptides (P11-4), stem cell therapies, 3D bioprinting, and gene-editing (CRISPR) technologies, which aim to biologically regenerate lost enamel and dentine. The field is rapidly evolving from a preventive to a restorative paradigm, with future directions focusing on biologically based, minimally invasive therapies to fully restore tooth structure and function. Full article

(This article belongs to the Special Issue Application of Biomimetic Materials in Regenerative and Restorative Dentistry)

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15 pages, 3625 KB

Open AccessArticle

Parameter Optimization of Biodegradable Composite PLA–Wood with New-Generation Infill Pattern

by Mehmet Kivanc Turan, Altug Bakirci, Yusuf Alptekin Turkkan and Fatih Karpat

Biomimetics 2026, 11(2), 106; https://doi.org/10.3390/biomimetics11020106 - 2 Feb 2026

Abstract

The increasing interest in sustainable materials has led to the development of bio-based composites for additive manufacturing applications. This study aimed to investigate the influence of key printing parameters and new-generation infill patterns together on the maximum compressive force of PLA–wood bio-composites produced [...] Read more.

The increasing interest in sustainable materials has led to the development of bio-based composites for additive manufacturing applications. This study aimed to investigate the influence of key printing parameters and new-generation infill patterns together on the maximum compressive force of PLA–wood bio-composites produced by Material Extrusion. By optimizing this material, low-cost wood-like products can be produced. New-generation 3D infill patterns (octet, cubic-subdivision, and lightning which is a biomimetic infill pattern) infill densities, printing temperatures, and layer heights were selected as variables/factors, and the Taguchi method was applied for design of the experiment. The signal-to-noise ratio and Analysis of Variance were used to evaluate the statistical significance and contribution of each parameter to the mechanical response. The signal-to-noise ratio indicated that the optimal printing settings were as follows: printing temperature, 205 °C; infill density, 80%; infill pattern, octet; and layer height, 0.2 mm (7123.4 N). ANOVA results showed that infill density was the most significant factor affecting maximum compressive force at 60%, while infill pattern also exhibited a notable effect. According to these results, infill density and infill pattern are the most important factors for achieving high compressive strength. These findings suggest that optimizing infill architecture and density can improve the mechanical performance of PLA–wood composites, also they can offer assistive design guidelines for lightweight and eco-friendly components. Full article

(This article belongs to the Special Issue Bio-Inspired Design for Structural and Sustainable Applications: 2nd Edition)

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30 pages, 1510 KB

Open AccessArticle

An Improved Mantis Search Algorithm for Solving Optimization Problems

by Yanjiao Wang and Tongchao Dou

Biomimetics 2026, 11(2), 105; https://doi.org/10.3390/biomimetics11020105 - 2 Feb 2026

Abstract

The traditional mantis search algorithm (MSA) suffers from limitations such as slow convergence and a high likelihood of converging to local optima in complex optimization scenarios. This paper proposes an improved mantis search algorithm (IMSA) to overcome these issues. An adaptive probability conversion [...] Read more.

The traditional mantis search algorithm (MSA) suffers from limitations such as slow convergence and a high likelihood of converging to local optima in complex optimization scenarios. This paper proposes an improved mantis search algorithm (IMSA) to overcome these issues. An adaptive probability conversion factor is designed, which adaptively controls the proportion of individuals entering the search phase and the attack phase so that the algorithm can smoothly transition from large-scale global exploration to local fine search. In the search phase, a probability update strategy based on both subspace and full space is designed, significantly improving the adaptability of the algorithm to complex problems by dynamically adjusting the search range. The elite population screening mechanism, based on Euclidean distance and fitness double criteria, is introduced to provide dual guidance for the evolution direction of the algorithm. In the attack stage, the base vector adaptive probability selection mechanism is designed, and the algorithm’s pertinence in different optimization stages is enhanced by dynamically adjusting the base vector selection strategy. Finally, in the stage of sexual cannibalism, the directed random disturbance update method of inferior individuals is adopted, and the population is directly introduced through the non-greedy replacement strategy, which effectively overcomes the loss of population diversity. The experimental results of 29 test functions on the CEC2017 test set demonstrate that the IMSA exhibits significant advantages in convergence speed, calculation accuracy, and stability compared to the original MSA and the five best meta-heuristic algorithms. Full article

(This article belongs to the Section Biological Optimisation and Management)

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43 pages, 1592 KB

Open AccessReview

Review of Soft Robotic Gloves and Functional Electrical Stimulation Affecting Hand Function Rehabilitation for Stroke Patients

by Xiaohui Wang, Yilin Fang, Zhaowei Zhang, Xingang Zhao, Dezhen Xiong and Junlin Li

Biomimetics 2026, 11(2), 104; https://doi.org/10.3390/biomimetics11020104 - 2 Feb 2026

Abstract

Stroke often results in impaired hand motor function, making effective hand rehabilitation essential for restoring activities of daily living (ADLs). Motor rehabilitation and neurorehabilitation are two major pathways to functional recovery. Rehabilitation gloves have proven to be effective tools for motor rehabilitation, and [...] Read more.

Stroke often results in impaired hand motor function, making effective hand rehabilitation essential for restoring activities of daily living (ADLs). Motor rehabilitation and neurorehabilitation are two major pathways to functional recovery. Rehabilitation gloves have proven to be effective tools for motor rehabilitation, and among them, soft robotic gloves (SRGs) have emerged as a research focus due to their lightweight design and inherent safety. Functional electrical stimulation (FES), which applies electrical currents to muscles and nerves, shows promise in promoting motor neural reorganization and restoring muscle strength in the hands of stroke survivors. The technologies applied to hand rehabilitation must possess the characteristics of safety, comfort, and practicality, while overcoming critical challenges such as portability, user-friendliness, and wearability. Motivated by the rehabilitation needs of post-stroke patients, this paper reviews recent advances in SRGs, FES, and hybrid hand rehabilitation systems (HHRSs) for hand rehabilitation, systematically examining progress in actuation strategies, intention sensing, and control algorithms across these three technologies. Furthermore, the limitations and technical challenges of current HHRSs are analyzed and four key future research directions are identified to pave the way for further development in this field. Full article

(This article belongs to the Special Issue Bioinspired Soft Robotics and Intelligent Actuation for Medical Rehabilitation, Prosthetic, and Surgical Systems)

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