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.
Increasing the viscosity of elastic joints can significantly improve the performance of elastic joint robots during physical human–robot interactions. However, current approaches for injecting viscous elements requir...
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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 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.
Versatile jumping is crucial for agile and adaptive behavior of humanoid robots in complex environments. However, humanoid robots have to manage impact forces while maintaining balance and stability throughout the tak...
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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...
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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.
Robustness walking and recovery ability in uneven terrains and unexpected collisions are crucial for the practical application of humanoid ***, existing methods struggle to effectively balance stability, motion safety...
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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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An important step before the implantation of an invasive brain-computer interface (BCI) is craniotomy, which provides direct access to the brain. During the craniotomy, the precision of cranial drilling is critical, a...
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The difficulty of moving from aquatic to aerial environment is one of the major challenges limiting the development of trans-medium multi-domain locomotion vehicles. In this paper, the concept of the transformable whe...
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Solar sail technology has been proposed and developed for space explorations with advantages of low launch cost,no-propellant consumption,and continuous thrust,which has great potentials in earth polar detection,inter...
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Solar sail technology has been proposed and developed for space explorations with advantages of low launch cost,no-propellant consumption,and continuous thrust,which has great potentials in earth polar detection,interstellar explorations and *** development of solar sail has made significant progress in structural design,manufacturing,materials,orbit transfer,and stability control in the past few decades,which makes meaningful contributions to astronomy,physics,and aerospace *** breakthroughs of Solar Radiation Pressure(SRP)propulsion and interstellar transfer have been achieved in current solar sail ***,there are still many challenges and problems need to be *** paper attempts to summarize the research schemes and potential applications of solar sailing in space missions from the viewpoint of key technologies,so as to provide an overall perspective for researchers in this *** of the key technologies of solar sailing system design are ***,challenges and prospective development of solar sailing are discussed.
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