Bioinspiration & Biomimetics最新文献

This study aims to enhance our understanding of human locomotion's adaptability to ground-level downward perturbations, focusing on hopping at preferred frequencies. By categorizing perturbations into early (ESP), mid (MSP), and late (LSP) stance phase and by analyzing the resulting biomechanical responses, we develop and validate a model that accurately replicates and predicts these behaviors. The spring-loaded inverted pendulum (SLIP) model, while capturing basic hopping dynamics, was inadequate for explaining subjects' responses. We introduced the sensory modulated spring (SMS) model, incorporating force, length, and velocity feedback (VFB), with gains optimized through genetic algorithms for enhanced accuracy. Our findings indicate distinct response patterns based on perturbation timing, highlighting the complexity of human adaptive mechanisms. The SMS model outperformed the SLIP model in replicating normal hopping behavior, while length and force feedback enable stable and economic human-like hopping, and VFB enables replicating humans' transient response to perturbation. Inspired by energy flow and behavioral changes in the experimental data, we introduced an extended SMS model with event-based adaptation at maximum compression and apex moment. The capability of this model to predict human perturbation recovery in hopping is demonstrated through systematic evaluation, including stability analyses and assessment of transient and steady-state responses. This study advances template-based modeling by integrating high-level reflexes besides local sensory feedback, offering a novel tool for understanding the inherent adaptability of human locomotion. The introduced adaptive model provides a novel framework for future research on adjustments to environmental challenges, with potential applications in designing effective rehabilitation protocols and assistive locomotion devices.

Maneuvering in fish is complex and offers inspiration in the development of the next generation bio-inspired underwater vehicles (BUVs). Balancing desired functionality with minimal mechanical complexity is a challenge in developing a BUV. This study presents a single-actuator turning strategy for the Tunabot, a bio-inspired robotic fish, using asymmetric tail-beat timing to generate turning forces. Biological fish, such as tuna, adjust tail kinematics for maneuverability. Following this principle, the proposed control method modifies stroke duration through a single motor, synchronized by a digital encoder. Experiments were conducted in a tank, using the dorsal-view high-speed video and DeepLabCut motion tracking technology to analyze and quantify turning radius and swimming velocity. A 66% asymmetric difference in tail-beat timing resulted in a turning radius of 1.42 body lengths at a certain base frequency. Scaling laws were developed to reveal the fluid dynamics and predict the turning radius and swimming speed of the Tunabot given known tailbeat frequencies. Power consumption data was gathered for asymmetric maneuvers and compared to their symmetric equivalents. These findings demonstrate that asymmetric tail-beat control enables effective turning without dedicated steering mechanisms, offering novel insights for designing highly maneuverable underwater bio-robots with low power consumption.

The tail of a bird-or a bird-inspired aerial robot-is an aerodynamically effective structure that enhances efficiency, stability, and manoeuvrability through attitude control and morphing. Optimising the morphology and structure of the tail can further improve the flight performance of such flyers. Inspired by previous studies on bird tails, we designed and developed a flexible tail capable of deforming in a bird-like manner. We investigated the effect of tail flexibility on the flight performance of a bird-inspired aerial robot through wind tunnel experiments and computational fluid dynamic analyses. Our results demonstrate that passive morphing of a tail with appropriate flexibility can adjust the tail surface orientation to direct aerodynamic force forward via pressure at the leading edge, thereby improving the lift-to-drag ratio and overall flight efficiency of the aerial robot. The proposed design also enables tail weight reduction, contributing to improved stability and manoeuvrability. These findings highlight tail flexibility as a key design parameter for improving the performance of bird-inspired aerial robots.

This paper presents the design and fabrication of a compact underdriven bionic frog robot, which is inspired by the locomotion stance of a frog. The robot's hind legs were ingeniously built using an underdriven associative 8-bar linkage mechanism with a single motor drive to mimic the swimming motion of a frog. To enhance the robot's biomechanics and locomotor capabilities, the robot's shell was designed to mimic biological features and adjust buoyancy. In addition, the body of the robot has three sealed chambers, which include a module for adjusting its center of gravity, an energy module, and a control and communication module. The robot is equipped with an integrated E30-170T27D transceiver chip specifically designed for wireless communication in shallow water. The Tensilica Xtensa LX6 microprocessor can perform sensor data acquisition and control robotic movements. Prototype experiments demonstrated that the frog robot is capable of achieving stable autonomous swimming and three-dimensional longitudinal movement. This is made possible by using two independently driven hind legs and a center-of-gravity adjustment mechanism. The robot exhibits an average speed of 100 mm s^-1. Furthermore, owing to its low drive, high bionic, and small design, the robot minimized perturbations to the water environment during underwater movement. This allows a stable water environment for underwater measurements and improves the overall endurance time. This study improves the overall endurance and provides a theoretical basis for the design of underdrive mechanisms for future bionic underwater robots.

To enhance the motion flexibility and environmental adaptability of underwater robots, this study proposes a novel design, Seeker-M, inspired by the locomotion mechanism of the mantis shrimp. The robot imitates the mantis shrimp's multi-pleopod swimming mode and has multi-modal locomotion ability. The robot features a multifunctional flexible spine capable of active bending (maximum angle of 30°) and dynamic center of gravity adjustment (up to 30% of body length). A pitch control system is developed based on this adjustable structure, employing the linear active disturbance rejection control (LADRC) algorithm. Experimental results demonstrate that the LADRC algorithm maintains robust attitude stability under disturbances from pleopod motion, offering an effective approach for underwater attitude control in complex environments.

Tensegrity describes a structural principle featuring a self-stabilizing system that consists of continuous tension elements and discontinuous compression elements. This paper undertakes a comprehensive systematic review of the overall development status and defining characteristics of the tensegrity field, employing bibliometric analysis methods and adopting an evolutionary perspective. Based on data spanning a 35 year period on the tensegrity theme sourced from the Web of Science database, we conducted detailed analyses of annual publication trends, significant authors, research areas, journals and co-occurrence maps of author keywords. These analyses collectively provide a nuanced description of the current state of the tensegrity field, as well as two pivotal sub-fields: biotensegrity and tensegrity robots. Through an analysis of research keywords and a timeline of evolving research hotspots within the tensegrity field, we have discerned a continuous evolution in the primary research focuses; from the initial conceptual application of tensegrity in the biological domain, to the subsequent refinement and development of tensegrity theory, and finally to ongoing advancements in tensegrity robots. From an evolutionary perspective, the dynamic transitions of research hotspots in tensegrity studies reflect both the field's progressive maturation and its expansion into emerging research frontiers. In addition, bioinspiration focuses on abstracting principles from nature to inspire novel solutions in other fields or sub-fields. Tensegrity structures exhibit explanatory compatibility with biological architectures. Based on this, the biotensegrity and tensegrity robots each belong to two bioinspiration pathways within the tensegrity framework. Tensegrity robots have emerged as the most prominent research sub-field within the broader conceptual framework of tensegrity, exhibiting a steadily increasing share of publications in the overall tensegrity literature. However, tensegrity robots still face a series of fundamental challenges, including the complexity of dynamic modeling and control, as well as the dilemma in structural optimization. Addressing these issues will likely depend on (1) improved theoretical models of tensegrity systems, (2) specialized tensegrity models tailored to different bio-inspired prototypes, and (3) novel integrations with various control methodologies. These directions are expected to remain key research focuses in the coming years.

Fish across many species share similar schooling behavior in which abundance flow interactions occur with hydrodynamic advantages from the vortex flow shed by the conspecifics. This study investigates the mechanisms of schooling interactions in thunniform swimmers, focusing on body effects, using high-fidelity three-dimensional direct numerical simulations of a pair of closely swimming tuna-like models with realistic body morphology and swimming kinematics. An in-house immerse-boundary-method-based incompressible Navier-Stokes flow solver is employed to resolve near-body vortex topology, and the results are analyzed in detail. The interaction mechanism is evaluated by varying the streamwise distance in the stagger formation from 0 to 1 body length (BL) in increments of 0.1 BL, and by introducing tailbeat phase differences at the optimal streamwise spacing, ranging from 0°to 360°in 45°increments. Results identify an optimal streamwise distance of 0.5 BL, where the following fish achieve enhanced forward force production and propulsive efficiency. Notably, the following fish benefits from improved performance across all tailbeat phase differences, as the wake-fin interaction remains robust for its thrust enhancement. Flow analysis reveals that the vortex interception contributes to a 16% thrust improvement on the in-phase follower, while its drag reduction results from a combination of constructive pressure field interactions generating strong anterior suction and wake-body interactions producing forward force on the posterior body. These effects are amplified by tailbeat phase differences, with a 270°phase difference yielding a 19% drag reduction on the following fish and 180°enabling constant drag reduction throughout the motion cycle. This study highlights the enhanced swimming performance of closely paired tuna-like swimmers and identifies interaction mechanisms, offering valuable insights into the hydrodynamics of fish schooling and potential applications in underwater robotics.

In pipe systems, the emergence of pipe-crawling robots (PCRs) has attracted significant attention for pipe inspection and repair applications. However, conventional PCRs are bulky and heavy, limiting their speed and adaptability, particularly in confined spaces. Additionally, their reliance on tethered power and signal transmission restricts mobility due to the constraints of external cables. To address those challenges, we propose a novel compact, untethered PCR powered by a battery-driven electromagnetic actuator inspired by earthworms. The optimized overlapping design of the magnet and coil enhances driving force, effectively supporting the robot and its onboard battery. We design a control module integrated into a printed circuit board (PCB) to achieve untethered functionality. To further enhance crawling efficiency, we incorporate bioinspired bristles with anisotropic friction at the robot's head and tail to ensure stable anchors during locomotion. Integrating electromagnetic actuator, PCB, and bristles, our bioinspired PCR achieves a lightweight, compact, untethered design capable of fast crawling, even in vertical orientations. Finally, our untethered PCR bears a 12 g onboard battery for both horizontal and vertical crawling, achieving remarkable crawling speeds of 55 BL min^-1(48.5 mm s^-1) horizontally and 16.3 BL min^-1(13 mm s^-1) vertically.

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.