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2024 IEEE International Conference on Unmanned systems, ICUS 2024

作者： Zhang, Shaojie Ni, Fenglei Li, Xueai Li, Xu Ji, Yi Shao, Xiangyu State Key Laboratory of Robotics and Systems Harbin Institute of Technology Harbin China Key Laboratory of Autonomous Intelligent Unmanned Systems Harbin Institute of Technology Harbin China

ISBN: (纸本)9798350384185

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 and walking *** paper proposes a hybrid control strategy combing Nonlinear Model Predictive Control (NMPC) and Whole-Body Control (WBC) to improve the robot's walking stability and reaction safety in collisions *** NMPC generates long-term and macroscopic movements, with capture point theory being utilized for foot placements determination under external *** this foundation, the WBC regulates the robot refinedly in real-time based on task priorities and *** verify the effectiveness of the proposed method, involving uneven terrain walking and external impacts rejection. © 2024 IEEE.

关键词： Anthropomorphic robots

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Bionic Jumping of Humanoid Robot via Online Centroid Trajectory Optimization and High Dynamic Motion Controller

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Journal of Bionic Engineering 2024年第6期21卷 2759-2778页

作者： Xiangji Wang Wei Guo Zhicheng He Rongchao Li Fusheng Zha Lining Sun State Key Laboratory of Robotics and System Harbin Institute of Technology(HIT)Harbin150001China Faculty of Computing Harbin Institute of Technology(HIT)Harbin150001China

The dynamic motion capability of humanoid robots is a key indicator for evaluating their ***,as a typical dynamic motion,is of great significance for enhancing the robot’s flexibility and terrain adaptability in unstructured ***,achieving high-dynamic jumping control of humanoid robots has become a challenge due to the high degree of freedom and strongly coupled dynamic *** idea for this paper originated from the human response process to jumping commands,aiming to achieve online trajectory optimization and jumping motion control of humanoid ***,we employ nonlinear optimization in combination with the Single Rigid Body Model(SRBM)to generate a robot’s Center of Mass(CoM)trajectory that complies with physical constraints and minimizes the angular momentum of the ***,a Model Predictive Controller(MPC)is designed to track and control the CoM trajectory,obtaining the required contact forces at the robot’s ***,a Whole-Body Controller(WBC)is used to generate full-body joint motion trajectories and driving torques,based on the prioritized sequence of tasks designed for the jumping *** control framework proposed in this paper considers the dynamic characteristics of the robot’s jumping process,with a focus on improving the real-time performance of trajectory optimization and the robustness of *** and experimental results demonstrate that our robot successfully executed high jump motions,long jump motions and continuous jump motions under complex working conditions.

关键词： Humanoid robots Jumping motion control Centroid trajectory optimization Optimization and optimal control

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Development of a high-performance bend-actuated piezoelectric tip/tilt stage with low power and simple operation

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Science China Technological Sciences 2025年第6期68卷 234-245页

作者： Jinghan GUAN Shijing ZHANG Jie DENG Weishan CHEN Junkao LIU Yingxiang LIU State Key Laboratory of Robotics and System Harbin Institute of Technology

Piezoelectric tip/tilt stages(PZT stages), which precisely and quickly control laser beam deflection, are widely used in laser communications. Most are driven by piezoelectric stack actuators(PSAs) and have high capacitance and power consumption. The negative voltage causes irreversible damage to PSAs. Therefore, negative voltage operation needs to be prohibited, which complicates manipulating the bidirectional deflection of the mirror. However, the aerospace field places higher requirements on power consumption and ease of operation, which makes the PZT stage require reduced power consumption and simple operation. This paper presents a high-performance bend-actuated PZT stage, which uses ceramic plates for driving, with a capacitance of only 26.4 nF/axis and a power of only 27 mW(at operating conditions of 1 mrad and 100 Hz).The sandwich structure allows for bi-directional voltage, which makes the operation easier. Two channels control two degrees of freedom(DOFs). A theoretical model suitable for bend-actuated structures is proposed. It is used to calculate the deflection angle and resonance frequency, and its validity is verified by finite element analysis. Experimental results show that it has a deflection angle of ±2.97 mrad(x-axis), ±3.24 mrad(y-axis) at 600 V p-p, an unloaded first-order resonance frequency of 1728 Hz, and a quasi-static hysteresis of only 7.5%, which is less than that of PSAs(>10%). With the constructed laser beam deflection system, a circular trajectory is realized, which has the potential for beam steering.

关键词： bending piezoelectric actuator tip/tilt stage laser beam deflection piezoelectric ceramic pseudo-rigid body model

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Mechanism of material removal and chip formation of alumina dispersion strengthened copper in micro-milling

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Frontiers of Mechanical Engineering 2025年第1期20卷 27-43页

作者： Chang LIU Chunya WU Xiguang LI Bo HOU Jiahao WU Ruijiang SUN Mingjun CHEN School of Mechatronics Engineering Harbin Institute of TechnologyHarbin 150001China State Key Laboratory of Robotics and System Harbin Institute of TechnologyHarbin 150001China

Alumina dispersion-strengthened copper (ADSC), as a representative particle-reinforced metal matrix composite (PRMMC), exhibits superior wear resistance and high strength. However, challenges arise in their processability because of the non-uniform material properties of biphasic materials. In particular, limited research has been conducted on the reinforcement mechanism and behavior of particles during material cutting deformation of PRMMC with nanoscale particles. In this study, a cutting simulation model for ADSC was established, separating the nanoscale reinforcement particles from the matrix. This model was utilized to analyze the interactions among particles, matrix, and tool during the cutting process, providing insights into chip formation and fracture. Particles with high strength and hardness are more prone to storing stress concentrations, anchoring themselves at grain boundaries to resist grain fibration, thereby influencing the stress distribution in the cutting deformation zone. Stress concentration around the particles leads to the formation of discontinuous chips, indicating that ADSC with high-volume fractions of particle (VFP) exhibits low cutting continuity, which is consistent with the results of cutting experiments. The tool tip that is in contact with particles experiences stress concentration, thereby accelerating tool wear. Cutting ADSC with 1.1% VFP results in tool blunting, which increases the radius of cutting edge from 0.5 to 1.9 μm, accompanied with remarkable coating delamination and wear. Simulation results indicate that the minimum uncut chip thickness increases from 0.04 to 0.07 μm as VFP increases from 0.3% to 1.1%. In conjunction with scratch experiments, MUCT increases with the augmentation of VFP. Computational analysis of the specific cutting force indicates that particles contribute to the material’s size effect. The results of this study provide theoretical guidance for practical engineering machining of ADSC, indicating its g

关键词： alumina dispersion-strengthened copper particle-reinforced metal matrix composites material removal mechanism micro-milling chip formation minimum uncut chip thickness

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Understand anisotropy dependence of damage evolution and material removal during nanoscratch of MgF_(2) single crystals

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International Journal of Extreme Manufacturing 2023年第1期5卷 236-252页

作者： Chen Li Yinchuan Piao Feihu Zhang Yong Zhang Yuxiu Hu Yongfei Wang State Key Laboratory of Robotics and System(HIT) Harbin Institute of TechnologyHarbin 150001People’s Republic of China

To understand the anisotropy dependence of the damage evolution and material removal during the machining process of MgF_(2) single crystals,nanoscratch tests of MgF_(2) single crystals with different crystal planes and directions were systematically performed,and surface morphologies of the scratched grooves under different conditions were *** experimental results indicated that anisotropy considerably affected the damage evolution in the machining process of MgF_(2) single crystals.A stress field model induced by the scratch was developed by considering the anisotropy,which indicated that during the loading process,median cracks induced by the tensile stress initiated and propagated at the front of the *** cracks induced by tensile stress initiated and propagated on the subsurface during the unloading *** addition,surface radial cracks induced by the tensile stress were easily generated during the unloading *** stress change led to the deflection of the propagation direction of lateral ***,the lateral cracks propagated to the workpiece surface,resulting in brittle removal in the form of chunk *** plastic deformation parameter indicated that the more the slip systems were activated,the more easily the plastic deformation *** cleavage fracture parameter indicated that the cracks propagated along the activated cleavage planes,and the brittle chunk removal was owing to the subsurface cleavage cracks propagating to the crystal *** the same processing parameters,the scratch of the(001)crystal plane along the[100]crystal-orientation was found to be the most conducive to achieving plastic machining of MgF_(2) single *** theoretical results agreed well with the experimental results,which will not only enhance the understanding of the anisotropy dependence of the damage evolution and removal process during the machining of MgF_(2) crystals,but also provide a theoretical foundation for achiev

关键词： anisotropy dependence damage evolution stress field crack propagation nanoscratch MgF_(2)single crystal

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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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Cable-driven legged landing gear for unmanned helicopter:Prototype design,optimization and performance assessment

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Science China(Technological Sciences) 2024年第4期67卷 1196-1214页

作者： TIAN BaoLin GAO HaiBo YU HaiTao SHAN HaoMin HOU JunChen YU HongYing DENG ZongQuan State Key Laboratory of Robotics and System Harbin Institute of TechnologyHarbin 150001China China Academy of Aerospace Science and Innovation Beijing 100048China

Unmanned helicopters equipped with adaptive landing gear will dramatically extend their application especially in dealing with challenging *** study presents a novel cable-driven legged landing gear(CLG)with differential transmission for unmanned helicopters in complex landing *** obtain the preferred configuration of the legged mechanism,a multi-objective optimization framework for the CLG is constructed by concurrently considering terrain adaptability,landing stability and reasonable linkage of internal *** non-dominated sorting genetic algorithmⅡis employed to numerically acquire the optimal scale parameters that guide the mechanical design of the *** unmanned helicopter prototype equipped with the devised CLG is developed with key performance *** results show that the devised CLG can provide energy-efficient support over uneven terrains(totally driven torque demand less than 0.1 N m)in quasi-static landing tests,and favorable terrain adaptability(posture fluctuation of the fuselage less than±1°)in unknown slope landing *** exhibited merits give the proposed CLG the potential to enhance the landing performance of future aircraft in extreme environments.

关键词： unmanned helicopter adaptive landing gear experimental verification

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3D printing of high-precision and ferromagnetic functional devices

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International Journal of Extreme Manufacturing 2023年第3期5卷 646-656页

作者： Zhiyuan Huang Guangbin Shao Dekai Zhou Xinghong Deng Jing Qiao Longqiu Li State Key Laboratory of Robotics and System Harbin Institute of TechnologyHarbinHeilongjiang 150001People’s Republic of China

The development of projection-based stereolithography additive manufacturing techniques and magnetic photosensitive resins has provided a powerful approach to fabricate miniaturized magnetic functional devices with complex three-dimensional spatial ***,the present magnetic photosensitive resins face great challenges in the trade-off between high ferromagnetism and excellent printing *** address these challenges,we develop a novel NdFeB-Fe_(3)O_(4) magnetic photosensitive resin comprising 20 wt.%solid loading of magnetic particles,which can be used to fabricate high-precision and ferromagnetic functional devices via micro-continuous liquid interface production *** resin combining ferromagnetic NdFeB microparticles and strongly absorbing Fe_(3)O_(4) nanoparticles is able to provide ferromagnetic capabilities and excellent printing quality simultaneously compared to both existing soft and hard magnetic photosensitive *** established penetration depth model reveals the effect of particle size,solid loading,and absorbance on the curing characteristics of magnetic photosensitive resin.A high-precision forming and ferromagnetic capability of the NdFeB-Fe_(3)O_(4) magnetic photosensitive resin are comprehensively *** is found that the photosensitive resin(NdFeB:Fe_(3)O_(4)=1:1)can print samples with sub-40μm fine features,reduced by 87%compared to existing hard magnetic photosensitive resin,and exhibits significantly enhanced coercivity and remanence in comparison with existing soft magnetic photosensitive resins,showing by an increase of 24 times and 6 times,*** reported NdFeB-Fe_(3)O_(4) magnetic photosensitive resin is anticipated to provide a new functional material for the design and manufacture of next-generation micro-robotics,electromagnetic sensor,and magneto-thermal devices.

关键词： magnetic device magnetic photosensitive resins 3D printing NdFeB Fe_(3)O_(4)

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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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Multi-granularity sequence generation for hierarchical image classification

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Computational Visual Media 2024年第2期10卷 243-260页

作者： Xinda Liu Lili Wang State Key Laboratory of Virtual Reality Technology and Systems Beihang UniversityBeijing 100191China Peng Cheng Laboratory Shengzhen 518000China

Hierarchical multi-granularity image classification is a challenging task that aims to tag each given image with multiple granularity labels *** methods tend to overlook that different image regions contribute differently to label prediction at different granularities,and also insufficiently consider relationships between the hierarchical multi-granularity *** introduce a sequence-to-sequence mechanism to overcome these two problems and propose a multi-granularity sequence generation(MGSG)approach for the hierarchical multi-granularity image classification ***,we introduce a transformer architecture to encode the image into visual representation ***,we traverse the taxonomic tree and organize the multi-granularity labels into sequences,and vectorize them and add positional *** proposed multi-granularity sequence generation method builds a decoder that takes visual representation sequences and semantic label embedding as inputs,and outputs the predicted multi-granularity label *** decoder models dependencies and correlations between multi-granularity labels through a masked multi-head self-attention mechanism,and relates visual information to the semantic label information through a crossmodality attention *** this way,the proposed method preserves the relationships between labels at different granularity levels and takes into account the influence of different image regions on labels with different *** on six public benchmarks qualitatively and quantitatively demonstrate the advantages of the proposed *** project is available at https://***/liuxindazz/mgs.

关键词： hierarchical multi-granularity classification vision and text transformer sequence generation fine-grained image recognition cross-modality attenti

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