Bioinspiration & Biomimetics最新文献

A corrugated wing is known to significantly enhance aerodynamic efficiency in the low Reynolds number regime. Although the result may be relatable directly to two-winged insects, larger insects flying at similar Reynolds numbers, like dragonflies, have four wings, and the role of the gap between the fore and hind wings in flight has rarely been analyzed. In particular, we perform direct numerical simulations of the flow past a tandem corrugated airfoil configuration at a chord Reynolds number of 10⁴that is of relevance to the micro-unmanned aerial vehicle (MAV) community. We assessed the tandem wing configuration for different horizontal and vertical offsets. In general, the aerodynamic efficiency for tandem configurations is quite high (∼ 10). Furthermore, we find that vertical offsets have a greater impact on aerodynamic forces than horizontal offsets. Positioning the hindwing below the forewing improves aerodynamic efficiency compared to placing the hindwing above because of the generation of a favorable pressure gradient on the forewing. The vortex shedding and correlations evaluate the hindwing/forewing interaction and the fluctuation of the forces. The horizontal offset results demonstrate improved aerodynamic efficiency and reduced flow unsteadiness as the gap between the two wings is minimized, primarily because the interaction between the forewing's wake and the hindwing is suppressed. A study with NACA 0008 is done to corroborate the range of optimal configurations and assess performance benefits of corrugated profile. In addition, the study reveals that the tandem wing configuration maintains efficiency comparable to that of a single wing, allowing us to utilize its advantages for MAV applications.

This study investigates the influence of center-of-mass (CoM) positioning on the pitch dynamics of damselfly-inspired flapping-wing micro aerial vehicles. We develop a simulation framework that integrates computational fluid dynamics, rigid-body dynamics, and self-propulsion model. Using experimentally measured and fixed wing kinematics, we systematically examine how different CoM positions affect pitch attitude, aerodynamic moments, and flight velocity. The results reveal that variations in CoM position significantly influence body pitch motion, which in turn alters local flow conditions, vortex formation, and moment arm interactions. These changes give rise to a passive pitching mechanism that regulates pitch oscillations and prevents divergence over short timescales. This bounded behavior suggests that insects may achieve transient flight stability through passive aerodynamic-inertial coupling, even in the absence of active control. Additionally, a rearward CoM suppresses downward pitch motion and promotes ascent, while a forward CoM increases forward velocity but limits ascent capability. The findings demonstrate that transient stabilization and flight modulation can be achieved solely through mass distribution, offering a low-complexity design strategy for bio-inspired MAVs.

Dexterous robotic hands have been a central focus in robotics research, aiming to replicate the versatility and functionality of the human hand. This review provides a comprehensive analysis of the latest advancements in the literature on dexterous robotic hands, covering both hardware designs and implementation methods. We categorize robotic hand dexterity into potential dexterity, grasp dexterity, and manipulation dexterity, offering a systematic framework for evaluating robotic hand performance. Various dexterous hands are then organized based on their number of digits, transmission mechanisms, actuation methods, and sensing technologies, with their dexterity compared using different evaluation criteria. Finally, we introduce various dexterous grasping and manipulation methods, including analytical approaches, machine-learning techniques, and sampling-based methods.

With the in-depth integration of research across multiple disciplines, such as biomimetics, robotics, and sensing technology, significant advancements have been made in swarm robotics technology, which has been applied in areas including drone swarms, mobile robot swarms, and underwater robot swarms. However, due to the limitations of underwater communication technologies, underwater robot swarms have lagged behind aerial and ground swarms in their development. This paper primarily explores the applications and advancements of swarm intelligence (SI) in multiple underwater robot swarms. Inspired by the behavior of animal swarms, researchers have translated this concept into the design and control strategies of underwater robot swarms. This approach draws on the self-organization, robustness, and adaptability inherent in collective behaviors, significantly enhancing the performance of underwater robot swarms. This paper provides a comprehensive review of the current research status of bio-inspired swarming of multiple underwater robots, including the design and classification of swarm underwater robots, SI algorithms and their applications in multiple underwater robots, and communication mechanisms for underwater robots. Furthermore, this paper highlights critical technical challenges that need to be addressed in research, along with proposed solutions, and discusses the vast application prospects of bio-inspired underwater swarming in military and civilian fields, providing clear directions for future research.

In recent years, the use of isotropic bionic fibrillar adhesives (BFA) in space non-cooperative target capture missions has become a research hotspot in the aerospace field. However, accurately evaluating the adhesion performance of these materials remains a critical challenge. To bridge this gap, we experimentally investigate the detachment behavior of two representative BFA types: mushroom-shaped fibrillar adhesives and flat-shaped fibrillar adhesives. The experimental results reveal that the critical detachment force (i.e. pull-off force) is significantly influenced by preload, detachment velocity, and detachment angle. Unlike the monotonic effects observed for preload and velocity, the detachment angle exhibits a non-monotonic relationship with the pull-off force. Specifically, as the detachment angle increases from 0° to 90°, the pull-off force first decreases and then increases. Further experimental validation and numerical simulations indicate that the equivalent bending moment induced by the pull-off force modulates the critical detachment angle-a phenomenon not reported in the existing literature. In addition, the fracture mode transitions from bilateral to unilateral crack propagation as the detachment angle decreases. Simulation results further demonstrate that the detachment angle alters the stress distribution at the adhesive interface, thereby affecting the crack propagation mode. Based on these findings, an approximate pull-off force model for BFA specimens is developed using linear elastic fracture mechanics, which incorporates the effects of preload, detachment velocity, and detachment angle. Following parameter identification, the proposed model accurately predicts the pull-off force for various loading conditions.

This article attempts to show that current trends in bio-inspired robotics research are incompatible with the transformations needed to address the current ecological crisis. A large part of the scientific community takes refuge behind short-term challenges to avoid facing the truth : contrary to some stated ambitions, bio-inspired and soft-robotics research activities are contributing to the overstepping of planetary limits, including the decline of biodiversity and global warming.

Owls have evolved remarkable adaptations for near-silent flight, offering a compelling model for understanding aerodynamic noise reduction. Their morphological specialisations-such as leading-edge serrations, trailing-edge fringes, and velvety wing surfaces-provide crucial insights into bioinspired solutions for various engineering applications. However, the exact aeroacoustic mechanisms underlying these adaptations remain only partially understood. This review provides a comprehensive synthesis of the key biomechanisms associated with silent flight, including both historical perspectives and the latest experimental and computational findings. We also systematically classify and analyse current biomimetic applications in various engineering contexts-including aircraft noise reduction, wind turbine blade optimisation, and other industrial implementations-thereby establishing a clear mechanistic link between fundamental aeroacoustic principles and real-world engineering solutions. Finally, we discuss the key challenges and future directions in owl-inspired aeroacoustics, emphasising the integration of morphological adaptations, wing flexibility, and flight kinematics. By bridging biological insights with engineering innovation, this work underscores the potential of owl-inspired designs to drive the development of quieter, more eco-friendly technologies.

In this paper, we investigate the hydrodynamic characteristics of harbor seal locomotion, focusing on the role of hind flippers in thrust generation and wake dynamics. Through three-dimensional numerical simulations using an immersed boundary method at Reynolds number of 3000, we analyze the impact of varying Strouhal number (St = 0.2-0.35) and propulsive wavelength (λ∗= 1.0-1.2) on swimming performance. Our findings reveal two distinct wake patterns: a single-row structure at lower Strouhal numbers (St⩽0.25) and a double-row configuration at higher St (St⩾0.3). Increasing wavelength generally enhances thrust production by reducing both pressure and friction of drag components. Additionally, we identify critical vortex interactions between the front and hind flippers, with destructive interference occurring at lower St and constructive patterns emerging at higher St. Circulation analysis confirms stronger vortex formation at higher St andλ∗, particularly during the left stroke phase. These results provide novel insights into the hydrodynamic mechanisms underlying seal locomotion and contribute to our understanding of efficient aquatic propulsion systems.

The application of unmanned aerial vehicles (UAVs) is surging across several industries, paralleled by growing demand for these UAVs. However, the noise emitted by UAVs remains a significant impediment to their widespread use even though in areas such as product delivery, they can be more environmentally friendly than traditional delivery methods. Nature has often been a source of inspiration for devices that are efficient and eco-friendly. In the current study, we leverage the previous work by Seoet al(2021Bioinsp. Biomim.16046019) on the aeroacoustics of flapping wing flight in mosquitoes and fruit flies to propose and examine a simple strategy for reducing the aeroacoustic noise from drone rotors. In particular, inspired by these insects, we explore how an increase in the planform area of the rotor could be used to reduce the rotation rate and the associated aeroacoustic noise from small-scale rotors. The study employs a sharp-interface immersed boundary solver for the flow simulations and the aeroacoustic sound is predicted by the Ffowcs Williams-Hawkings equation. Simulations indicate that the simple strategy of employing rotors with larger planform areas could lead not just to reduced aeroacoustic noise but improved power economy as well.