Bioinspiration & Biomimetics最新文献

Gecko-inspired adhesives offer strong, reversible, and directionally tunable adhesion, yet fabrication methods often depend on cleanroom lithography or proprietary molds, limiting scalability and accessibility. This study presents a low-cost, modular fabrication strategy combining high-resolution digital light processing 3D printing with 1000 lines/mm optical diffraction gratings to create hierarchical elastomeric adhesives. The resulting structures feature macroscale micropillars and embedded sub-micron surface topography, enabling effective contact splitting without advanced microfabrication. Mechanical testing reveals a nonlinear increase in shear performance with contact area, with maximum shear forces exceeding 80 N at 103.2 cm². Peel testing across varied angles and surface areas demonstrates anisotropic adhesion, with peak peel strength of 21.94 N and detachment energy of 3.88 Jm-2at a 30° peel angle for patch area of 103.2 cm². A comparative cost analysis highlights the accessibility of this method, revealing a 10-100xreduction in fabrication cost relative to cleanroom and roll-to-roll-based techniques. This approach enables reproducible microstructure transfer, optical validation, and application-specific tunability, offering a practical, scalable pathway for bio-inspired adhesives in robotics, wall-climbing systems, and soft interface applications.

This paper presents a coupled framework for simulating fish schooling, integrating social interactions through a self-propelled particle (SPP) model and flow dynamics via computational fluid dynamics (CFD). In the SPP model, the fish interact with a finite number of topologically defined neighbors, whereas in the CFD model, the fish follow the positions and orientations prescribed by the SPP model through undulatory motion. The undulatory kinematics are generated using a pre-trained deep reinforcement learning model from prior simulation data. Although the CFD trajectories do not exactly match those of the SPP model, they closely approximate them, providing a useful degree of flexibility that allows for physical realism while preserving computational efficiency. For example, in simulations of a minimal two-fish group, the trailing fish achieves stable locomotion through a slight side-slip, an emergent behavior not explicitly encoded in the SPP input. The model is further extended to large schools, demonstrating that group efficiency increases with the Reynolds number because of more favorable hydrodynamic interactions.

The presence of gaps between feathers is known to enhance the aerodynamic performance of birds during flapping flight. To investigate the underlying flow mechanisms of this phenomenon, we numerically investigate a two-dimensional zero-thickness flat-plate airfoil with a hinged perforation. The immersed boundary-lattice Boltzmann method is employed to simulate the flow over a zero-thickness flat-plate airfoil, where the hinge-representing a feather gap-is prescribed to open during the upstroke and close during the downstroke. The effects of the gap position, size, and maximum opening angle on aerodynamic performance are systematically analyzed. The results demonstrated that, within the studied parameter ranges, upward perforations increased the pressure differential near the leading edge, while downward perforations reduced it. However, hinge-related vortices generated downstream of the perforations partially offset these pressure differential effects. For downward perforations, optimal positioning, larger sizes, and greater maximum opening angles significantly improved the lift and lift efficiency. Upward perforations enhanced the aerodynamic performance only under restricted perforated conditions: positioning at a distance of 0.25 times the chord length from the leading edge, sizes of less than 0.2 times the chord length, and maximum opening angles of less than 30°. Downward perforations generally outperformed upward configurations in terms of lift and lift efficiency, making them preferable for engineering applications, though self-propulsion effects and three-dimensional flow interactions require further investigation. These findings provide insights for optimizing the perforation designs in micro-flapping-wing vehicles.

Traditional soft robotic grippers often lack the structural rigidity required to maintain stable poses under external forces, as well as the fine control and precision offered by rigid grippers or conventional robotic hands. These limitations are particularly significant in tasks requiring dexterous manipulation, such as in-hand manipulating objects. This paper proposes a bio-inspired spine mechanism capable of self-adapting to the variable length of the finger, thus increasing strength and stiffness without compromising the intrinsic compliance of soft fingers. A passive inflatable soft fingertip design is further introduced to enhance grasp stability. The performance of the proposed soft fingers mounted on a reconfigurable palm is evaluated through stiffness characterization, grasping tests, and in-hand manipulation demonstrations. Experiments show that the spine substantially increases both front and side stiffness and improves grasp stability under dynamic conditions. With the combined advantages of reconfigurable palm mechanism and the adaptive soft fingers, the proposed Soft Reconfigurable Hand achieves robust grasping and stable in-hand manipulations across diverse tasks.

In biomimetic underwater systems, high-efficiency and low-power propulsion remains a core challenge. Mimicking the characteristics of fish caudal fins and exploring highly biomimetic muscle-driven approaches is regarded as one of the key strategies to address this issue.This study combines the immersed boundary-lattice Boltzmann method with deep reinforcement learning (DRL) to investigate the interactive effects of caudal fin structural stiffness and active muscle control on propulsive performance and energy consumption.By constructing a virtual fish model with a closed-loop 'perception-decision-action' feature, the agent can autonomously learn to output tail torque based on environmental feedback, thereby regulating the deflection behavior of the caudal fin. The research evaluates the differences in dynamic responses between rigid and flexible caudal fin configurations under both passive states and active control intervention. The results indicate that rigid caudal fins exhibit significant phase lag and increased energy consumption without control; however, driven by DRL strategies, they can achieve phase compensation and a substantial improvement in propulsive performance. In contrast, flexible caudal fins, relying on stronger passive adaptability, can achieve superior propulsive efficiency in the uncontrolled state, while their speed and energy consumption can be further optimized with the introduction of active regulation.To realize dynamic trade-offs between speed and energy consumption, this study develops a task-sensitive multi-objective dynamic reward function, enabling the agent to switch between 'high-speed propulsion' and 'high-efficiency energy-saving' strategies according to requirements. This research not only reveals the synergistic relationship between structural compliance and active control but also demonstrates the potential of DRL in exploring optimal control strategies without prior knowledge. It provides a new research path and theoretical support for the intelligent regulation of bionic fish caudal fins and the design of flexible underwater robots.

Bird forelimbs exhibit complex flight kinematics, including wing morphing and flapping motions with angle asymmetry. However, data on angle-asymmetric flapping in birds are scarce, and well-established theories and methods remain limited. Motivated by this challenge, we present a biofeature reconstruction method of the Morphlight theory that integrates high-speed videography with millimeter resolution 3D scanning to better approximate these kinematic features. Frame-by-frame analysis ofAquila nipalensiswingbeat sequences quantified joint rotations with angle-asymmetric, after which a three-rod Tang model and corresponding flapping equation of the Morphlight theory were formulated to predict the rotational angles of the wing joints. The bird's wings were then scanned to obtain key aerofoil profiles, which were used to construct a bionic airfoil incorporating the secondary remiges. Guided by the measured kinematics, we designed the drive mechanism and implemented a sliding crank-rocker mechanism to realize angle-asymmetric motion during the upstroke and downstroke. The resulting morphing flight vehicleMorphSteppeachieves high biofidelity in both wing geometry and angle-asymmetric flapping kinematics. Both flapping tests without inflow and outdoor flapping experiments were conducted to evaluate the aerodynamic performance and controllability of the morphing flight vehicle. The proposed Morphlight theory inspired by raptor, provides a generalizable framework for high biofidelity design of bird morphing flight vehicle that couples biological morphology with angle-asymmetric flapping kinematics.

Biomimicry offers sustainable, efficient, and adaptable solutions inspired by natural systems. The skeleton of Euplectella aspergillum (EA) represents a highly optimized biological structure. It is composed of silica-based elements known as spicules, which interlock to form a lattice-like framework that provides strength and flexibility. In this study, the structural and functional properties of EA spicules were investigated. The macrostructure revealed a well-organized, multi-component framework consisting of a filter cap, spiral crest, skeletal wall, and anchor base-features that contribute to hydrodynamic efficiency and mechanical stability. The hierarchical architecture was characterized using scanning electron microscopy, atomic force microscopy (AFM), nanoindentation, thermogravimetric analysis, differential scanning calorimetry, and x-ray diffraction (XRD). At the microscale, spicules exhibited a laminated architecture of silica and organic layers, which redirect crack propagation and dissipate energy, enhancing fracture resistance. Nanoindentation and AFM revealed mechanical properties across the spicule cross-section, with an average hardness of 4.436 ± 0.202 GPa, reduced modulus of 39.596 ± 0.374 GPa, and stiffness of 21.200 ± 0.517µN nm^-1. Sink-in behavior indicated the elastic and brittle nature of both silica and organic regions. Localized pile-up near organic interfaces highlighted plastic deformation constraints due to mechanical heterogeneity. Thermal analysis identified approximately 9.83% organic content and confirmed high thermal stability of the silica matrix. A crystallization event occurring at approximately 1090 °C corresponded to the transformation of amorphous silica intoβ-cristobalite, as confirmed by XRD. These findings provide insights into the structural and mechanical properties of EA skeleton, supporting the design of high-performance ceramic materials with enhanced mechanical properties for bioengineering applications.

Flapping Counter Torque (FCT) is an intrinsic mechanism in flapping-wing flight of animals, where the rotation of an animal's body creates asymmetric left-right wing motion, leading to a counter torque that opposes the body rotation. FCT corresponds to a passive damping effect that could be harnessed for disturbance rejection and flight stabilization, but its role in fast maneuvers remains unclear. In this work, we used the reconstructed escape flight of hummingbirds to test the effects of FCT in fast maneuvers, which features rapid and simultaneous body pitch, roll, and yaw, and linear accelerations. In addition to Computational Fluid Dynamics (CFD) simulation of free-body flight, we also performed a fixed-body CFD simulation by removing the body-rotation induced wing velocities while retaining the wing kinematics relative to the body. The aerodynamic torques from the fixed-body flight are considered active torques, and the differences between the free and fixed-body flights are considered the FCTs. Our results show that the FCT in the roll axis is particularly strong during downstroke, due to the large bilateral wing velocity asymmetry associated with the body roll, as well as changes to the wings' angle of attack by body rotations around the other axes. To overcome the strong damping and sustain the rotation, the bird utilizes an active torque to overcome the FCT during downstrokes and also employs the wing kinematics that would incur less FCT during upstrokes. Overall, the hummingbird is able to alleviate and control the FCT and still achieve great agility in the maneuver.

There is a growing interest in unmanned aerial vehicles (UAVs) being able to perch onto objects, which expands their scope of applications. Many perching strategies are inspired by natural organisms, including birds, insects, and helical morphologies such as tendrils and tails. Inspired by these helical structures, a bistable hybrid gripper is developed that enables a quadcopter to perch on branches and perform aerial grasping. The gripper integrates a bistable steel shell (BSS) as the stiff element, analogous to skeletal support, with a soft 3D-printed helical exoskeleton, analogous to muscular compliance, to achieve both structural strength and adaptability. This hybrid design not only enables conformal wrapping and high load capacity but also allows the UAV to grasp without continuous energy input due to its bistable mechanism. Static models are established to predict the pneumatic transition pressure between the two states, and the results are validated experimentally. Furthermore, the holding and grasping forces, along with robustness against tilt and rotation offsets, are systematically characterized, confirming adaptability to branches with varying diameters and orientations. Experimental demonstrations confirm that UAVs equipped with the gripper can reliably perch on tree branches and perform aerial grasping in realistic field environments.

Adaptive handling of thick or composition-changing fluids is difficult for conventional pumps. In animals, the intestine addresses this challenge by switching between segmental mixing and peristaltic transport according to the physical state of the contents. We translate this principle into a silicone soft pump composed of four pneumatic chambers, each driven by its own phase oscillator. Two tunable factors govern the collective behaviour: (i) the coupling strength, which attempts to maintain neighbouring oscillators in a travelling-wave relationship, and (ii) the local sensor feedback, which forces each oscillator to correct the deformation error of its own chamber. Numerical bifurcation analysis and time-domain simulations show that when the two strengths are balanced within an intermediate range, the controller first generates an antiphase pattern that homogenises a viscous mixture, and then spontaneously shifts to a quarter-cycle travelling wave that drives the now-fluid contents downstream. We built a physical prototype and experimentally confirmed autonomous mode switching between two glycerol-based fluids of contrasting viscosity. These results demonstrate that a minimal, bioinspired, distributed controller can endow soft devices with adaptive, multifunctional pumping capability, thereby opening new routes to food-processing, biomedical, and chemical-handling systems that operate under uncertain conditions.