The novel autonomous rolling performance is realized by the pair of pectoral fins of a three-dimensional(3-D)bionic dolphin in this paper numerically.3-D Navier-Stokes equations are employed to simulate the viscous fl...
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The novel autonomous rolling performance is realized by the pair of pectoral fins of a three-dimensional(3-D)bionic dolphin in this paper numerically.3-D Navier-Stokes equations are employed to simulate the viscous fluid around the bionic *** effect of self-rolling manoeuvrability is ex-plored using the dynamic mesh technology and user-defined function(UDF).By varying the parameter ratios,the interaction of flexible pectoral fins is divided into two motion modes,amplitude differential and frequency differential *** the primary driving source,the differential motion of a pair of pec-toral fins can effectively provide the rolling torque,and the trajectory of the entire rolling process is approximately the clockwise *** results demonstrate that the rolling angular velocity and driving torque in the steady state can be improved by increasing parameter ratios,and the rolling efficiency can reach the maximum under the optimal parameter ***,different parameter ratios do not af-fect the rolling radius of the self-rolling *** evolution process around the pair of pectoral fins is shown by the flow structures in self-rolling swimming,reasonably revealing that self-rolling locomotion is produced by the pressure and wake vortices surrounding the pair of pectoral fins,and the wake struc-tures depend primarily on the variation of parameter *** properly turns out that the application of the pair of pectoral fins can realize the self-rolling performance through parameter differential modes.
Model-guided design of dielectric elastomer actuators(DEAs) is essential for enabling their application in soft robotics. However, current modeling methods primarily rely on the finite element method(FEM), which s...
Model-guided design of dielectric elastomer actuators(DEAs) is essential for enabling their application in soft robotics. However, current modeling methods primarily rely on the finite element method(FEM), which suffers from low computational efficiency. Additionally, the simulation-to-reality(Sim2Real) gap, mainly arising from variations in material properties and manufacturing processes, poses a significant challenge. In this work, we propose a data-driven modeling framework aimed at accurately and rapidly predicting voltage-induced displacements while minimizing the Sim2Real gap. The framework integrates a multi-layer perceptron(MLP) model, which serves as a computationally efficient surrogate for the FEM model, and a cycle-generative adversarial network(CycleGAN) model, which mitigates the Sim2Real gap by leveraging adversarial learning to process both simulation and experimental data. Dimensional analysis is performed to extend the framework's applicability across different DEA scales. The surrogate model delivers global predictions in just 0.8 s, achieving linear coefficients of determination(R2) of 0.99106 for release distance prediction and 0.99375 for actuation distance prediction compared to experimental results. Our model can quickly identify the feasible range of biaxial prestretch ratios required for generating the desired deformation, thereby streamlining the design process. Finally, a soft robotic gripper is designed and fabricated, demonstrating versatile object-grasping capabilities.
The inverse kinematics problems of robots are usually decomposed into several Paden–Kahan subproblems based on the product of exponential model. However, the simple combination of subproblems cannot solve all the inv...
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The inverse kinematics problems of robots are usually decomposed into several Paden–Kahan subproblems based on the product of exponential model. However, the simple combination of subproblems cannot solve all the inverse kinematics problems, and there is no common approach to solve arbitrary three-joint subproblems in an arbitrary postural relationship. The novel algebraic geometric (NAG) methods that obtain the general closed-form inverse kinematics for all types of three-joint subproblems are presented in this paper. The geometric and algebraic constraints are used as the conditions precedent to solve the inverse kinematics of three-joint subproblems. The NAG methods can be applied in the inverse kinematics of three-joint subproblems in an arbitrary postural relationship. The inverse kinematics simulations of all three-joint subproblems are implemented, and simulation results indicating that the inverse solutions are consistent with the given joint angles validate the general closed-form inverse kinematics. Huaque III minimally invasive surgical robot is used as the experimental platform for the simulation, and a master–slave tracking experiment is conducted to verify the NAG methods. The simulation result shows the inverse solutions and six sets given joint angles are consistent. Additionally, the mean and maximum of the master–slave tracking experiment for the closed-form solution are 0.1486 and 0.4777 mm, respectively, while the mean and maximum of the master–slave tracking experiment for the compensation method are 0.3188 and 0.6394 mm, respectively. The experiments results demonstrate that the closed-form solution is superior to the compensation method. The results verify the proposed general closed-form inverse kinematics based on the NAG methods.
Although significant advances in the design of soft robotic hands have been made to mimic the structure of the human hands,there are great challenges to control them for coordinated and human-like *** on the principle...
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Although significant advances in the design of soft robotic hands have been made to mimic the structure of the human hands,there are great challenges to control them for coordinated and human-like *** on the principle of postural synergies in the human hand,we present a synergistic approach for coordinated control of a soft robotic hand to replicate the human-like grasp *** this end,we firstly develop a kinematic model to describe the control variables and the various postures of the soft robotic *** on the postural synergies,we use the developed model and Principal Component Analysis(PCA)method to describe the various postures of the soft robotic hand in a low-dimensional space formed by the synergies of actuator ***,the coordinates of these synergies can be used as low-dimensional control inputs for the soft robotic hand with a higher-dimensional postural ***,we establish an experimental platform on a customized soft robotic hand with6 pneumatical actuators to verify the effectiveness of the *** results demonstrate that with only a 2-dimensional control input,the soft robotic hand can reliably replicate 30 grasp postures in the Feix taxonomy of the human hand.
Swarming magnetic micro/nanorobots hold great promise for biomedical applications,but at present suffer from inferior capabilities to perceive and respond to chemical signals in local *** we demonstrate swarming magne...
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Swarming magnetic micro/nanorobots hold great promise for biomedical applications,but at present suffer from inferior capabilities to perceive and respond to chemical signals in local *** we demonstrate swarming magnetic photonic crystal microrobots(PC-bots)capable of sponta-neously performing on-the-fly visual pH detection and self regulated drug delivery by perceiving local pH *** magnetic PC-bots consist of pH-responsive hydrogel microspheres with encapsulated one-dimensional periodic assemblies of Fe3O4 *** programming extemnal rotating magnetic fields,they can self-organize into large swarms with much-enhanced collective velocity to actively find targets while shining bright“blinking”structural *** approaching the target with abnormal pH conditions(*** ulcerated superficial tumor lesion),the PC-bots can visualize local pH changes on the fly via pH-responsive structural colors,and realize self-regulated release of the loaded drugs by recognizing local *** work facilita tes the develop-ment of intelligent micro/nanorobots for active“motile-targeting”tumor diag-nosis and treatment.
The hydrodynamic performance of the virtual underwater vehicle under self-yaw is investigated numerically in this paper,we aim to explore the fluid laws behind this plane motion achieved by the bionic flexibility,espe...
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The hydrodynamic performance of the virtual underwater vehicle under self-yaw is investigated numerically in this paper,we aim to explore the fluid laws behind this plane motion achieved by the bionic flexibility,especially the spanwise flexibility of the caudal *** kinematics of the chordwise flexible body and the spanwise flexible caudal fin are explored through dynamic mesh technology and user-defined functions(UDF).The 3-D Navier-Stokes equations are applied to simulate the viscid fluid surrounding the bionic *** study focuses on quantitative problems about the fluid dynamics behind the specific motion law,including speed of movement,energy loss and working *** current results show that the self-yaw can be composed of two motions,autonomous propulsion and active *** addition,the degree of the flexible caudal fin can produce different yaw *** chordwise phase differenceФis dominant in the propulsion function,while the spanwise phase differenceδhas a more noticeable effect on the steering *** pressure distribution on the surface of the dolphin and the wake vortex generated in the flow field reasonably reveal the evolution of *** properly turns out that the dolphin can combine the spanwise flexible caudal fin and the chordwise flexible body to achieve self-yaw motion.
It is vital to recognize the intention of finger motions for human-machine interaction(HMI).The latest research focuses on fine myoelectric control through the decoding of neural motor unit action potential trains(MUA...
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It is vital to recognize the intention of finger motions for human-machine interaction(HMI).The latest research focuses on fine myoelectric control through the decoding of neural motor unit action potential trains(MUAPt) from high-density surface electromyographic(sEMG) ***,the existing EMG decoding algorithms rarely obtain the spatial matching relationship between decoded motion units(MU) and designated muscles,and the control interface can only recognize the trained hand *** this study,a semi-supervised HMI based on MU-muscle matching(MMM) is proposed to recognize individual finger motions and even the untrained combined multi-finger *** automatic channel selection from high-density s EMG signals,the optimal spatial positions to monitor the MU activation of finger muscles are *** tapping experiment is carried out on ten subjects,and the experimental results show that the proposed s EMG decomposition algorithm based on MMM can accurately identify single finger motions with an accuracy of 93.1%±1.4%,which is comparable to that of state-of-the-art pattern recognition ***,the MMM allows unsupervised recognizing the untrained combined multi-finger motions with an accuracy of 73%±3.8%.The outcomes of this study benefit the practical applications of HMI,such as controlling prosthetic hand and virtual keyboard.
Small pipes exist in industrial and biomedical fields,and require microrobots with high operational precision and large load capacity to inspect or perform functional tasks.A piezoelectric inertial pipeline robot usin...
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Small pipes exist in industrial and biomedical fields,and require microrobots with high operational precision and large load capacity to inspect or perform functional tasks.A piezoelectric inertial pipeline robot using a“stick-slip”mechanism was proposed to address this *** this study,the driving principle of the proposed robot was analyzed,and the strategy of the design scheme was presented.A dynamics model of the stick-slip system was established by combining the dynamics model of the driving foot system and the LuGre friction model,and the simulation analysis of the effect of system parameters on the operating trajectory was *** experimental system was established to examine the output characteristics of the proposed *** results show that the proposed pipeline robot with inertial stick-slip mechanism has a great load capacity of carrying 4.6 times(70 g)its own mass and high positioning *** speed of the pipeline robot can reach up to 3.5 mm/s(3 mm/s)in the forward(backward)direction,with a minimum step distance of 4µ*** potential application for fine operation in the pipe is exhibited by a demonstration of contactless transport.
Given an untrimmed video, repetitive actions counting aims to estimate the number of repetitions of class-agnostic actions. To handle the various length of videos and repetitive actions, also optimization challenges i...
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Accurate identification of the subthalamic nucleus (STN) borders is time-consuming, relying heavily on the neurosurgeon expertise in manually interpreting the electrophysiological signals. Local field potentials (LFPs...
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