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Simulation and analysis of asteroid force closure anchoring performance based on discrete element method

Chinese Journal of Aeronautics 2023年第8期36卷 381-394页

作者： Tingzhang WANG Qiquan QUAN Hongshuai GAO Mengxue LI Dewei TANG Zongquan DENG State Key Laboratory of Robotics and System Harbin Institute of TechnologyHarbin 150001China

Asteroid exploration is significant for studying the origin of the solar system,establishing planetary defenses,and alleviating the resource crisis of the *** anchoring is the basis of in-situ exploration and resource development and ***,the performance of asteroid force-closure anchoring is investigated using the discrete element *** micro parameters of the simulated materials are calibrated with angle of repose and uniaxial compression experiments,based on which the regional modeling method is adopted to establish the anchoring discrete element *** anchoring experiments are conducted on a self-developed microgravity simulation platform to verify the accuracy of the simulation *** asteroid anchoring simulations are performed to investigate the influence of external force on the anchoring *** analysis of anchoring force varying with time and the interaction between the anchor and regolith particles reveals the influence mechanism of external force direction on the anchoring *** external force direction affects the critical anchoring force by influencing the failure of the force-closure *** comprehensive analysis of simulation results clarifies the variation of the critical anchoring force with the external ***,a stable anchoring region is established,beneficial for asteroid anchoring device design.

关键词： Anchoringforce Asteroid exploration Discrete element method Force closureanchoring Simulationverification

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A policy iteration method for improving robot assembly trajectory efficiency

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Chinese Journal of Aeronautics 2023年第3期36卷 436-448页

作者： Qi ZHANG Zongwu XIE Baoshi CAO Yang LIU State Key Laboratory of Robotics and System Harbin Institute of TechnologyHarbin 150001China

Bolt assembly by robots is a vital and difficult task for replacing astronauts in extravehicular activities(EVA),but the trajectory efficiency still needs to be improved during the wrench insertion into hex hole of *** this paper,a policy iteration method based on reinforcement learning(RL)is proposed,by which the problem of trajectory efficiency improvement is constructed as an issue of RL-based objective ***,the projection relation between raw data and state-action space is established,and then a policy iteration initialization method is designed based on the projection to provide the initialization policy for *** iteration based on the protective policy is applied to continuously evaluating and optimizing the action-value function of all state-action pairs till the convergence is *** verify the feasibility and effectiveness of the proposed method,a noncontact demonstration experiment with human supervision is *** results show that the initialization policy and the generated policy can be obtained by the policy iteration method in a limited number of demonstrations.A comparison between the experiments with two different assembly tolerances shows that the convergent generated policy possesses higher trajectory efficiency than the conservative *** addition,this method can ensure safety during the training process and improve utilization efficiency of demonstration data.

关键词： Bolt assembly Policy initialization Policy iteration Reinforcement learning(RL) Robotic assembly Trajectory efficiency

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Hybrid Static-dynamic Sensation Electrotactile Feedback for Hand Prosthesis Tactile and Proprioception Feedback

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Journal of Bionic Engineering 2023年第1期20卷 267-277页

作者： Bin Yang Li Jiang State Key Laboratory of Robotics and System Harbin Institute of TechnologyHarbin150001China

Tactile and proprioception feedback are essential to myoelectric hand prostheses control for regaining functionality of lost hands of *** studies focus on tactile feedback,while the lack of appropriate multisensory feedback,especially proprioception feedback,limits the grasping ***,a typical non-invasive stimulation scheme for sensation feedback uses stimulation on the stationary site of the skin continuously,which can lead to fatigue and adaptation of sensation,further reduces the feedback consistency,and increases the cognitive burden for the *** the sensitivity and modality matching of sensation,this study presented a multimodal sensations feedback scheme based on hybrid static-dynamic sensation elicited by multisite Transcutaneous Electrical Nerve Stimulation(TENS)to deliver grasping force and joint position *** the proposed scheme,stimulation of single electrode produced only in-loco tactile sensation under the electrode,and the sensation intensity was adjusted according to grasping force;sequential activation of multi-electrodes produced an illusion dynamic sensation of a stimulus moving,and the velocity and direction of movement were adjusted according to finger joint *** test results demonstrated the identifiability of stimulus in the proposed ***,prosthetic hand closed-loop grasping tasks evaluate the effectiveness of the proposed feedback *** results showed that the proposed feedback scheme could substantially improve the grasping accuracy and *** addition,the study outcomes also demonstrated the benefit of artificial proprioception feedback in grasping rapidity and security.

关键词： TENS-Prosthetic hand control-Bioinspired sensation-Multimodal sensations Proprioception feedback Tactilefeedback Myoelectric control

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A 3-DOF piezoelectric robot with continuous walking gait aiming at cross-scale smooth motion

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Science China(Technological Sciences) 2023年第1期66卷 233-242页

作者： YU HongPeng LIU YingXiang DENG Jie ZHANG ShiJing CHEN WeiShan State Key Laboratory of Robotics and System Harbin Institute of TechnologyHarbin 15000lChina

Piezoelectric robots play important roles in the field of micromanipulation, but it is difficult for them to generate steady precision motion at any moment. In order to eliminate the changing inertial force and improve the motion smoothness, this work proposes a piezoelectric robot with continuous walking gait inspired by ants. The idea is verified with theoretical models and numerical simulation, and the performances are evaluated with experiments. The robot is proven to have the ability to generate 3-DOF(dgeree of freedom) continuous smooth motions with constant speeds. The maximum and minimum smooth velocities have a difference of six orders of magnitude, realizing cross-scale velocity control. Besides, the motion resolution reaches several nanometers with the unlimited workspace, so the cross-scale displacement control can be also obtained. Furthermore, with great robustness against varying loads, the stable actuation capability of the robot is more than 22 times of the self-weight. To sum up,the proposed robot generates cross-scale smooth motion in both aspects of displacement and velocity, so it has good prospects in the applications requiring steady precision motion. The design philosophy and research methods in this work can be valuable references for further advances of micromanipulation robots.

关键词： piezoelectric robot continuous walking gait cross-scale displacement cross-scale velocity smooth motion constant speed

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High-efficiency inspecting method for mobile robots based on task planning for heat transfer tubes in a steam generator

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Frontiers of Mechanical Engineering 2023年第2期18卷 161-175页

作者： Biying XU Xuehe ZHANG Yue OU Kuan ZHANG Zhenming XING Hegao CAI Jie ZHAO Jizhuang FAN State Key Laboratory of Robotics and System Harbin Institute of TechnologyHarbin 150001China

Many heat transfer tubes are distributed on the tube plates of a steam generator that requires periodic inspection by *** inspection robots are usually involved in issues:Robots with manipulators need complicated installation due to their fixed base;tube mobile robots suffer from low running efficiency because of their structural *** there are thousands of tubes to be checked,task planning is essential to guarantee the precise,orderly,and efficient inspection *** in-service robots check the task tubes using row-by-row and column-bycolumn *** leads to unnecessary inspections,resulting in a long shutdown and affecting the regular operation of a nuclear power ***,this paper introduces the structure and control system of a dexterous robot and proposes a task planning *** method proceeds into three steps:task allocation,base position search,and sequence *** allocate the task regions,this method calculates the tool work matrix and proposes a criterion to evaluate a *** then all tasks contained in the sub-region are considered globally to search the base ***,we apply an improved ant colony algorithm for base sequence planning and determine the inspection orders according to the planned *** validated the optimized algorithm by conducting task planning experiments using our robot on a tube *** results show that the proposed method can accomplish full task coverage with few repetitive or redundant inspections and it increases the efficiency by 33.31% compared to the traditional planning algorithms.

关键词： steam generator transfer tubes mobile robot dexterous structure task planning efficient inspection

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Light weight design and integrated method for manufacturing hydraulic wheel-legged robots

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2024年第9期25卷 701-715页

作者： Xu LI Haoyang YU Huaizhi ZONG Haibo FENG Yili FU State Key Laboratory of Robotics and System Harbin Institute of TechnologyHarbin 150001China State Key Laboratory of Fluid Power and Mechatronic Systems Zhejiang UniversityHangzhou 310058China

Design and manufacturing play pivotal roles in hydraulic-driven robotic ***,previous studies have emphasized mainly results and performance,often overlooking the specifics of the design and manufacturing *** paper introduces a novel approach known as light weight design and integrated manufacturing(LD&IM)for hydraulic wheel-legged *** LD&IM method leverages topology optimization and generative design techniques to achieve a substantial 45%weight reduction,enhancing the robot’s dynamic motion *** innovative design method not only streamlines the design process but also upholds the crucial attributes of light weight construction and high strength essential for hydraulic wheel-legged ***,the integrated manufacturing method,incorporating selective laser melting(SLM)and high-precision subtractive manufacturing(SM)processes,expedites the fabrication of high-quality *** the LD&IM approach,a hydraulic-driven single wheel-legged robot,denoted as WLR-IV,has been successfully *** robot boasts low mass and inertia,high strength,and a simplified component *** assess its dynamic jumping capabilities,the control loop integrates a linear quadratic regulator(LQR)and zero dynamic-based controller,while trajectory planning uses the spring-loaded inverted pendulum(SLIP)*** jumping results confirm the WLR-IV single-legged robot’s exceptional dynamic performance,validating both the effectiveness of the LD&IM method and the rationale behind the control strategy.

关键词： Wheel-legged robot Hydraulic driven Topology optimization Wheel-legged robot Hydraulic driven Topology optimization Additive manufacturing(AM) Jump control

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Hemispherical resonator with low subsurface damage machined by small ball-end fine diamond grinding wheel:A novel grinding technique

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Chinese Journal of Aeronautics 2024年第5期37卷 570-585页

作者： Biao QIN Henan LIU Jian CHENG Jinchuan TIAN Jiangang SUN Zihan ZHOU Chuanzhen MA Mingjun CHEN State Key Laboratory of Robotics and System Harbin Institute of TechnologyHarbin 150001China Center for Precision Engineering Harbin Institute of TechnologyHarbin 150001China

As for the ultra-precision grinding of the hemispherical fused silica resonator,due to the hard and brittle nature of fused silica,subsurface damage(SSD)is easily generated,which enormously influences the performance of such ***,ultra-precision grinding experiments are carried out to investigate the surface/subsurface quality of the hemispherical resonator machined by the small ball-end fine diamond grinding *** influence of grinding parameters on the surface roughness(SR)and SSD depth of fused silica samples is then *** experimental results indicate that the SR and SSD depth decreased with the increase of grinding speed and the decrease of feed rate and grinding *** addition,based on the material strain rate and the maximum undeformed chip thickness,the effect of grinding parameters on the subsurface damage mechanism of fused silica samples is ***,a multi-step ultra-precision grinding technique of the hemispherical resonator is proposed based on the interaction influence between grinding depth and feed ***,the hemispherical resonator is processed by the proposed grinding technique,and the SR is improved from 454.328 nm to 110.449 nm while the SSD depth is reduced by 94%from 40μm to 2.379μ*** multi-step grinding technique proposed in this paper can guide the fabrication of the hemispherical resonator.

关键词： Fused silica Ultra-precision grinding Hemispherical resonator Subsurface damage Grinding technique

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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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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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