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Simultaneously improving fabrication accuracy and interfacial bonding strength of multi-material projection stereolithography by multi-step exposure

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International Journal of Smart and Nano Materials 2024年第2期15卷 387-404页

作者： Xinghong Deng Guangyu Zhang Yi Mo Zhiyuan Huang Dekai Zhou Jing Qiao Longqiu Li State Key Laboratory of Robotics and System Harbin Institute of TechnologyHarbinChina School of Materials Science and Engineering Harbin Institute of TechnologyHarbinChina

Multi-material additive manufacturing(MMAM)takes full advantage of the ability to arbitrarily place materials of addi-tive manufacturing technology,enabling immense design free-dom and functional print *** MMAM technologies,projection stereolithography(PSL)exhibits a great balance of high resolution and fast printing ***,fabrication accuracy of multi-material PSL is hin-dered by large overcure used to strengthen interfacial bond-ing weakened by chemical affinity and material-exchange *** present a novel multi-step exposure method for multi-material PSL process to overcome this ***,the whole layer is moderately exposed producing over-cure of single-material PSL level to generate *** weakened interfaces are strengthened individually with addi-tional steps of *** multi-step exposure is integrated into the already efficient materials printing order of multi-material PSL *** depth and overcure of photocur-able resins are modeled and *** required to achieve sufficient interfacial bonding of single-material interfaces built through material-exchange process and multi-material interfaces with altering materials printing order is determined with tensile *** channels are used to compare fabrication accuracy of traditional single-step exposure and our multi-step exposure *** method can be widely applied in multi-material PSL to improve fabri-cation accuracy in a variety of applications including micro-fluidic devices.

关键词： Additive manufacturing multi-material projection stereolithography multi-step exposure interfacial bonding

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Motion Attitude and Aerodynamic Characteristics Research of Flapping Wings Driven by Micro Servoactuator

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Journal of Bionic engineering 2024年第6期21卷 2830-2846页

作者： Tianyou Mao Bosong Duan Bihui Yin Chuangqiang Guo State Key Laboratory of Robotics and System Harbin Institute of TechnologyHarbin150001China School of Mechanical Engineering Zhejiang UniversityHangzhou310027China

Compared to the traditional flapping-wing structure with single motion mode,a micro servoactuator driven Flapping-Wing Air Vehicle(FWAV)breaks free from the limitations imposed by the motion parameters of the crank-connecting rod *** allows for simultaneous control of wings’position and velocity attitude through pulse width modulation,showcasing unrivaled controllability and promising extensive ***,this method of motion control also brings new challenges to the design of the wings’motion *** study seeks to investigate the relationship between the motion parameters of micro servoactuator driven FWAV and its aerodynamic characteristics,then explore a servo control method that can optimize its thrust-producing *** achieve this,this paper involves the establishment of Amplitude Loss Model(ALM),Flapping Wing Dynamic Model(FWDM),and Power Load Model(PLM),followed by motion capture experiments,dynamic monitoring experiments,and power monitoring *** results show that the proposed modeling method,which fully considers the amplitude loss effect and advanced twisting effect in flapping-wing motion,can accurately calculate thrust,power,and power load,with prediction errors of less than 10%,5%and 13%,*** high-precision model can effectively optimize motion parameters,allowing for better performance of flapping-wing motion.

关键词： Flapping wing Micro servoactuator Motion attitude Aerodynamic model

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Using spanwise flexibility of caudal fin to improve swimming performance for small fishlike robots

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Journal of Hydrodynamics 2018年第5期30卷 859-871页

作者： Dan Xia Wei-shan Chen Jun-kao Liu Xiang Luo School of Mechanical Engineering Southeast UniversityNanjing 211189China State Key Laboratory of Robotics and System Harbin Institute of TechnologyHarbin 150001China

This paper examines the beneficial effects of the spanwise flexibility of the caudal fin for the improvement of the swimming performance for small fishlike robots. A virtual swimmer is adopted for controlled numerical experiments by varying the spanwise flexible trajectories and the spanwise flexible size of the caudal fin while keeping the body kinematics fixed. 3-D Navier-Stokes equations are used to compute the viscous flow over the robot. Elliptical, parabolic and hyperbola trajectories are chosen to describe the spanwise flexible profile of the caudal fin. According to the sign（positive or negative） of the phase difference of the swinging motion, the spanwise flexibility can be divided into the fin surface of ＂bow＂ and the fin surface of ＂scoop＂. It is observed that for both the fin surface of ＂bow＂ and the fin surface of ＂scoop＂, the spanwise elliptical trajectory has the optimal swimming velocity, thrust, lateral force, and efficiency. With comparisons, using the flexible caudal fin with the fin surface of ＂bow＂, the lateral force and the power consumption can be reduced effectively and the swimming stability can be increased while reducing little the swimming velocity and thrust. Meanwhile, using the flexible caudal fin with the fin surface of ＂scoop＂ can greatly improve the swimming velocity, thrust, and efficiency while increasing part of the lateral force and the power consumption. Three-dimensional flow structures clearly indicate the evolution process around the swimming robot. It is suggested that the fish, the dolphin, and other aquatic animals may benefit their hydrodynamic performance by the spanwise flexibility of the caudal fin.

关键词： Spanwise flexibility caudal fin fishlike robot swimming performance flow structures

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DP4AuSu: Autonomous Surgical Framework for Suturing Manipulation Using Diffusion Policy With Dynamic Time Wrapping-Based Locally Weighted Regression

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The International Journal of Medical robotics and Computer Assisted Surgery 2025年第3期21卷

作者： Wenda Xu Zhihang Tan Zexin Cao Haofei Ma Gongcheng Wang Han Wang Weidong Wang Zhijiang Du State Key Laboratory of Robotics and System Harbin Institute of Technology Harbin China Department of Industrial and Systems Engineering The Hong Kong Polytechnic University Hong Kong China

Background Emerging imitation learning (IL) approaches have provided innovative solutions for completing surgical robotic suturing autonomously, significantly aiding surgeons in their manipulations. Methods We introduce Diffusion Policy for Autonomous Suturing (DP4AuSu), a novel framework that leverages diffusion policy (DP) and dynamic time wrapping-based locally weighted regression to achieve autonomous robotic suturing. Results In simulation, DP4AuSu achieved a 94% success rate for insertion subtasks over 50 trials. In a real-world setting, it achieves 85% success rate over 20 trials for suturing manipulations in 390.55–41.59s faster than conventional diffusion policy. Conclusions Our novel framework can capture the multimodality in demonstrations and successfully learn the suturing policy and reduce the suturing time. To the best of our knowledge, this work represents the first application of diffusion policy for robotic suturing. We hope this research paves the way for the automation of more complex surgical tasks.

关键词： autonomous suturing dynamic time wrapping imitation learning locally weighted regression robot learning surgical robot

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Improving Kinematic Flexibility and Walking Performance of a Six-legged Robot by Rationally Designing Leg Morphology

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Journal of Bionic engineering 2019年第4期16卷 608-620页

作者： Jie Chen Zhongchao Liang Yanhe Zhu Jie Zhao School of Mechanical Engineering and Automation Northeastern UniversityShenyang 110819China State Key Laboratory of Robotics and System Harbin Institute of TechnologyHarbin 150001China

This paper explores the design of leg morphology in a six-legged *** by nature,where animals have different leg morphology,we examined how the difference in leg morphology influences behaviors of the *** this end,a systematic search was conducted by scanning over the parameter space consisting of default angles of leg joints of the six-legged robot,with two main objectives:to maximize the kinematic flexibility and walking performance of the *** show that(1)to have a high kinematic flexibility with both the torso and swing legs,the femur segment should tilt downwards by 5°-10°and the tibia segment should be vertically downwards or with a slight inward tilt;(2)to achieve relatively energy-efficient and steady walking,the tibia segment should be approximately vertically downwards,with the femur segment tilting upwards to lower the torso *** results of this study suggest that behaviors of legged robots can be passively enhanced by careful mechanical design choices,thereby leading to more competent legged machines.

关键词： six-legged robot leg morphology kinematic flexibility walking performance

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Precise semi-analytical inverse kinematic solution for 7-DOF offset manipulator with arm angle optimization

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Frontiers of Mechanical engineering 2021年第3期16卷 435-450页

作者： Boyu MA Zongwu XIE Zainan JIANG Hong LIU School of Mechatronics Engineering Harbin Institute of TechnologyHarbin 150001China State Key Laboratory of Robotics and System Harbin Institute of TechnologyHarbin 150001China

Seven-degree-of-freedom redundant manipulators with link offset have many advantages,including obvious geometric significance and suitability for configuration *** configuration is similar to that of the experimental module manipulator(EMM)in the Chinese Space Station Remote Manipulator ***,finding the analytical solution of an EMM on the basis of arm angle parameterization is *** study proposes a high-precision,semi-analytical inverse method for ***,the analytical inverse kinematic solution is established based on joint angle ***,the analytical inverse kinematic solution for a non-offset spherical-roll-spherical(SRS)redundant manipulator is derived based on arm angle *** approximate solution of the EMM is calculated in accordance with the relationship between the joint angles of the EMM and the SRS ***,the error is corrected using a numerical method through the analytical inverse solution based on joint angle *** selecting the stride and termination condition,the precise inverse solution is computed for the EMM based on arm angle ***,case solutions confirm that this method has high precision,and the arm angle parameterization method is superior to the joint angle parameterization method in terms of parameter selection.

关键词： 7-DOF redundant manipulator inverse kinematics semi-analytical arm angle link offset

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An energy harvester combining a piezoelectric cantilever and a single degree of freedom elastic system

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Journal of Zhejiang University-Science A(Applied Physics & engineering) 2012年第7期13卷 526-537页

作者： Hong-yan WANG Xiao-biao SHAN Tan XIE State Key Laboratory of Robotics and System Harbin Institute of Technology Harbin 150001China College of Computer and Control Engineering Qiqihar UniversityQiqihar 161006China

This paper presents a type of vibration energy harvester combining a piezoelectric cantilever and a single degree of freedom (SDOF) elastic system. The main function of the additional SDOF elastic system is to magnify vibration displacement of the piezoelectric cantilever to improve the power output. A mathematical model of the energy harvester is developed based on Hamilton's principle and Rayleigh-Ritz method. Furthermore, the effects of the structural parameters of the SDOF elastic system on the electromechanical outputs of the energy harvester are analyzed numerically. The accuracy of the output performance in the numerical solution is identified from the finite element method (FEM). A good agreement is found between the numerical results and FEM results. The results show that the power output can be increased and the frequency bandwidth can be improved when the SDOF elastic system has a larger lumped mass and a smaller damping ratio. The numerical results also indicate that a matching load resistance under the short circuit resonance condition can obtain a higher current output, and so is more suitable for application to the piezoelectric energy harvester.

关键词： Piezoelectric cantilever Single degree of freedom elastic (SDOF) system Energy harvesting Finite element analysis(FEA)

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Learning to Identify Footholds from Geometric Characteristics for a Six-legged Robot over Rugged Terrain

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Journal of Bionic engineering 2020年第3期17卷 512-522页

作者： Jie Chen Chong Liu Haibin Zhao Yanhe Zhu Jie Zhao School of Mechanical Engineering and Automation Northeastern UniversityShenyang 110819China State Key Laboratory of Robotics and System Harbin Institute of TechnologyHarbin 150001China

Foothold identification is a key ability for legged robots that allows generating terrain adaptive behaviors(e.g.,gait and control parameters)and thereby improving mobility in complex *** this end,this paper addresses the issue of foothold characterization and identification over rugged terrain,from the terrain geometry point of *** a terrain region that might be a potential foothold of a robotic leg,the characteristic features are extracted as two first-order partial derivatives and two curvature parameters of a quadric regression surface at this *** features are able to give an intuitive and,more importantly,accurate characterization towards the specific geometry of the ground *** this basis,a supervised learning technique,Support Vector Machine(SVM),is employed,seeking to Ieam a foothold identification policy from human expert *** a result,an SVM classifier is leamt using the extracted features and human-demonstrated labels,which is able to identify whether or not a certain ground location is suited as a safe foot support for a robotic *** is shown that over 90%identification rate can be achieved with the proposed ***,preliminary experiment is implemented with a six-legged robot to demonstrate the effectiveness of the proposed approach.

关键词： six-legged robot foothold characterization foothold identification geometric characteristics support vector machine

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Parametric Gait Online Generation of a Lower-limb Exoskeleton for Individuals with Paraplegia

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Journal of Bionic engineering 2018年第6期15卷 941-949页

作者： Tianjiao Zheng Yanhe Zhu ZongweiZhang Sikai Zhao Jie Chen Jie Zhao State Key Laboratory of Robotics and System Harbin Institute of Technology Harbin 150001 China School of Mechanical Engineering and Automation Northeastern University Shenyang 110819 China

Lower-limb exoskeletons can provide paraplegics with the ability to restore gait function. In the community ambulation, the user would frequently meet different floors, doorsills, and other obstacles. Therefore, parametric gait generation is a significant issue for this kind of exoskeletons. In this paper, a parametric gait online generation approach is proposed, which combines a parametric gait control method with a torque compensation control strategy, based on the state machine. In the torque compensation control, the reference tra- jectories of joint positions are obtained through compensating gravity, inertia, and friction, which is intent on the natural and well-directed source data. Based on the reference trajectories, the parametric gait control method is established, in which the gait can be controlled via three parameters： velocity, step-length, and step-height. Two test cases are performed on three healthy subjects. The results demonstrate that the parametric gait can be online generated smoothly and correctly, meanwhile every variable step can be triggered as users expect. The effectiveness and practicability of the gait generation approach proposed in this paper are validated. In addition, this research is the foundation of autonomous gait planning.

关键词： exoskeleton parametric gait gait online generation paraplegic bionic design

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QRS detection algorithm for long term Holter records

QRS detection algorithm for long term Holter records

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14th International Conference on Computer systems and Technologies, CompSysTech 2013

作者： Georgieva-Tsaneva, Galya Institute of System Engineering and Robotics Bulgarian Academy of Sciences Bulgaria

ISBN: (纸本)9781450320214

In this paper an exact QRS detection algorithm of Holter electrocardiogram signals using Wavelet Transform is present. The orthogonal wavelet functions - Haar and Daubechies - is studied and compared. Analysis is carried out using Visual C++ Software. The results show that the described algorithm provides excellent QRS detection even if the signals are contaminated with noises. The presented algorithm is less computationally involved. This makes it ideal for wide range of diagnostic applications, especially for real-time Holter monitoring. © 2013 ACM.

关键词： Electrocardiograms

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