Biomimetic Intelligence and Robotics最新文献

The selective attenuation and scattering of light in underwater environments cause color distortion and contrast reduction in underwater images, which can impede the ever-growing demand for underwater robot operations. To address these issues, we propose a Multi-Color space Residual Network (MCRNet) for underwater image enhancement. Our method takes advantage of the unique features of color representation in the RGB, HSV, and Lab color spaces. By utilizing the distinct feature representations of images in different color spaces, we can highlight and fuse the most informative features of the three color spaces. Our approach employs a self-attention mechanism in the multi-color space feature fusion module. Extensive experiments demonstrate that our method achieves satisfactory results in color correction and contrast improvement of underwater images, particularly in severely degraded scenes. Consequently, our method outperforms state-of-the-art methods in both subjective visual comparison and objective evaluation metrics.

With high flexibility and slim body, flexible robots have been widely used in minimally invasive surgery because they can safely reach the lesion deep inside the human body through small incisions or natural orifices. However, high stiffness of robot body is also required for transferring force and maintaining the motion accuracy. To meet these two contradictory requirements, various methods have been implemented to enable adjustable stiffness for flexible surgical robots. In this review, we first summarize the anatomic constraints of common natural tracts of human body to provide a guidance for the design of variable stiffness flexible robots. And then, the variable stiffness methods have been categorized based on their basic principles of varying the stiffness. In the end, two variable stiffness methods with great potential and the moving strategy of variable stiffness flexible robots are discussed.

Tactile sensing enables high-precision 3D shape perception when vision is limited. However, tactile-based shape reconstruction remains a challenging problem. In this paper, a novel visuotactile sensor, GelStereo Palm 2.0, is proposed to better capture 3D contact geometry. Leveraging the dense tactile point cloud captured by GelStereo Palm 2.0, an active shape reconstruction pipeline is presented to achieve accurate and efficient 3D shape reconstruction on irregular surfaces. GelStereo Palm 2.0 achieves a spatial resolution of 1.5 mm and a reconstruction accuracy of 0.3 mm. The accuracy of the proposed active shape reconstruction pipeline reaches 2.3 mm within 18 explorations. The proposed method has potential applications in the shape reconstruction of transparent or underwater objects.

Continuum robots, which are characterized by high length-to-diameter ratios and flexible structures, show great potential for various applications in confined and irregular environments. Due to the combination of motion modes, the existence of multiple solutions, and the presence of complex obstacle constraints, motion planning for these robots is highly challenging. To tackle the challenges of online and flexible operation for continuum robots, we propose a flexible head-following motion planning method that is suitable for scalable and bendable continuum robots. Firstly, we establish a piecewise constant curvature (PCC) kinematic model for scalable and bendable continuum robots. The article proposes an adaptive auxiliary points model and a method for updating key nodes in head-following motion to enhance the precise tracking capability for paths with different curvatures. Additionally, the article integrates the strategy for adjusting the posture of local joints of the robot into the head-following motion planning method, which is beneficial for achieving safe obstacle avoidance in local areas. The article concludes by presenting the results of multiple sets of motion simulation experiments and prototype experiments. The study demonstrates that the algorithm presented in this paper effectively navigates and adjusts posture to avoid obstacles, meeting the real-time demands of online operations. The average time for a single-step solution is $4.41\times 10^{-5}$ s, and the average tracking accuracy for circular paths is 7.8928 mm.

Swift perception of interaction forces is a crucial skill required for legged robots to ensure safe human–robot interaction and dynamic contact management. Proprioceptive-based interactive force is widely applied due to its outstanding cross-platform versatility. In this paper, we present a novel interactive force observer, which possesses superior dynamic tracking performance. We propose a dynamic cutoff frequency configuration method to replace the conventional fixed cutoff frequency setting in the traditional momentum-based observer (MBO). This method achieves a balance between rapid tracking and noise suppression. Moreover, to mitigate the phase lag introduced by the low-pass filtering, we cascaded a Newton Predictor (NP) after MBO, which features simple computation and adaptability. The precision analysis of this method has been presented. We conducted extensive experiments on the point-foot biped robot BRAVER to validate the performance of the proposed algorithm in both simulation and physical prototype.

Acoustic propulsion system presents a novel underwater propulsion approach in small scale swimmer. This study introduces a submerged surface acoustic wave (SAW) propulsion system based on the SiO₂/Al/LiNbO ₃ structure. At 19.25 MHz, the SAW propulsion system is proposed and investigated by the propulsion force calculation, PIV measurements and propulsion measurements. 3.3 mN propulsion force is measured at 27.6 V${}_{pp}$. To evaluate the miniature swimmer, the SAW propulsion systems with multiple frequencies are studied. At 2.2 W, the submerged SAW propulsion system at 38.45 MHz demonstrates 0.83 mN/mm${}^2$ propulsion characteristics. At 96.13 MHz and 24 V${}_{pp}$, the movements of miniature swimmer with a fully submerged SAW propulsion system are recorded and analyzed to a maximum of 177 mm/s. Because of miniaturization, high power density, and simple structure, the SAW propulsion system can be expected for some microrobot applications, such as underwater drone, pipeline robot and intravascular robot.

Crocodiles, one of the oldest and most resilient species on Earth, have demonstrated remarkable locomotor abilities both on land and in water, evolving over millennia to adapt to diverse environments. In this study, we draw inspiration from crocodiles and design a highly biomimetic crocodile robot equipped with multiple degrees of freedom and articulated trunk joints. This design is based on comprehensive analysis of the structural and motion characteristics of real crocodiles. The bionic crocodile robot has a problem of limb-torso incoordination during movement. To solve this problem, we used the D-H method for both forward and inverse kinematics analysis of the robot’s legs and spine. Through a series of simulation experiments, we investigated the robot’s motion stability, fault tolerance, and adaptability to environments in two motor patterns: with and without spine and tail movements. The experimental results show that the bionic crocodile robot exhibits superior motion performance when the spine and tail cooperate with the extremities. This study not only demonstrates the potential of biomimicry in robotics but also underscores the significance of understanding how nature’s designs can inform and enhance technological innovations.

With the increase in the number of stroke patients, there is a growing demand for rehabilitation training. Robot-assisted training is expected to play a crucial role in meeting this demand. To ensure the safety and comfort of patients during rehabilitation training, it is important to have a patient-cooperative compliant control system for rehabilitation robots. In order to enhance the motion compliance of patients during rehabilitation training, a hierarchical adaptive patient-cooperative compliant control strategy that includes patient-passive exercise and patient-cooperative exercise is proposed. A low-level adaptive backstepping position controller is selected to ensure accurate tracking of the desired trajectory. At the high-level, an adaptive admittance controller is employed to plan the desired trajectory based on the interaction force between the patient and the robot. The results of the patient–robot cooperation experiment on a rehabilitation robot show a significant improvement in tracking trajectory, with a decrease of 76.45% in the dimensionless squared jerk (DSJ) and a decrease of 15.38% in the normalized root mean square deviation (NRMSD) when using the adaptive admittance controller. The proposed adaptive patient-cooperative control strategy effectively enhances the compliance of robot movements, thereby ensuring the safety and comfort of patients during rehabilitation training.

The performance of Aquatic Unmanned Aerial Vehicle (AquaUAV) has always been limited so far and far from practical applications, due to insufficient propulsion, large-resistance structure etc. Aerial-aquatic amphibians in nature may facilitate the development of AquaUAV since their excellent amphibious locomotion capabilities evolved under long-term natural selection. This article will take four typical aerial-aquatic amphibians as representatives, i.e., gannet, cormorant, flying fish and flying squid. We summarized the multi-mode locomotion process of common aerial-aquatic amphibians and the evolutionary trade-offs they have made to adapt to amphibious environments. The four typical propulsion mechanisms were investigated, which may further inspire the propulsion design of the AquaUAV. And their morphological models could guide the layout optimization. Finally, we reviewed the state of art in AquaUAV to validate the potential value of our bioinspiration, and discussed the future prospects.

In the field of pipeline inner wall inspection, the snake robot demonstrates significant advantages over other inspection methods. While a simple traveling wave or meandering motion will suffice for inspecting the inner wall of small-diameter pipes, comprehensively and meticulously inspecting the inner wall of large-diameter pipes requires the snake robot to adopt a helical gait that closely adheres to the inner wall. Our review of existing literature indicates that most research and development on the helical gait of snake robots has focused on the outer surface of cylinders, with very few studies dedicated to developing a helical gait specifically for the inspection of the inner wall of pipes. Therefore, in this study, we propose a helical gait that is suitable for the inner wall of pipes and meets the requirements of gas pipeline engineering. The helical gait is designed using the backbone curve method. First, we create a mathematical model for a circular helix curve with constant curvature and torsion, ensuring it is applicable to a snake robot prototype in a laboratory environment. Subsequently, we calculate the joint angles required for two conical spiral curves with variable curvature and torsion, establish a new model, and define the physical significance of the specific parameters. To ensure the feasibility of the proposed gait, we conduct experiments involving meandering and traveling wave motions to verify the communication and control between the host computer and the snake robot. Building upon this foundation, we further validate the mathematical model of the complex helical motion gait through simulation experiments. Our findings provide a theoretical basis for realizing helical movement with a real snake robot.