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arXiv 2025年

作者： Zhao, Xiongwei Wang, Yang Sun, Qihao Bai, Haojie Xie, Xingxiang Shenzhen518071 China State Key Laboratory of Robotics and System Harbin Institute of Technology Harbin150006 China School of Information Communication Technology Shenzhen Institute of Information Technology Shenzhen518071 China

LiDAR place recognition (LPR) plays a vital role in autonomous navigation. However, existing LPR methods struggle to maintain robustness under adverse weather conditions such as rain, snow, and fog, where weather-induced noise and point cloud degradation impair LiDAR reliability and perception accuracy. To tackle these challenges, we propose an Iterative Task-Driven Framework (ITDNet), which integrates a LiDAR Data Restoration (LDR) module and a LiDAR Place Recognition (LPR) module through an iterative learning strategy. These modules are jointly trained end-to-end, with alternating optimization to enhance performance. The core rationale of ITDNet is to leverage the LDR module to recover the corrupted point clouds while preserving structural consistency with clean data, thereby improving LPR accuracy in adverse weather. Simultaneously, the LPR task provides feature pseudo-labels to guide the LDR module’s training, aligning it more effectively with the LPR task. To achieve this, we first design a task-driven LPR loss and a reconstruction loss to jointly supervise the optimization of the LDR module. Furthermore, for the LDR module, we propose a Dual-Domain Mixer (DDM) block for frequency-spatial feature fusion and a Semantic-Aware Generator (SAG) block for semantic-guided restoration. In addition, for the LPR module, we introduce a Multi-Frequency Transformer (MFT) block and a Wavelet Pyramid NetVLAD (WPN) block to aggregate multi-scale, robust global descriptors. Finally, extensive experiments on the Weather-KITTI, Boreas, and our proposed Weather-Apollo datasets demonstrate that, demonstrate that ITDNet outperforms existing LPR methods, achieving state-of-the-art performance in adverse weather. The datasets and code will be made publicly available at https://***/Grandzxw/ITDNet. © 2025, CC BY.

关键词： Image coding

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MM-LINS: a Multi-Map LiDAR-Inertial system for Over-Degenerate Environments

arXiv

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arXiv 2025年

作者： Ma, Yongxin Xu, Jie Yuan, Shenghai Zhi, Tian Yu, Wenlu Zhou, Jun Xie, Lihua School of Mechanical Engineering Shandong University Jinan250061 China Key Laboratory of High Efficiency and Clean Mechanical Manufacture Ministry of Education Jinan250061 China State Key Laboratory of Robotics and Systems Harbin Institute of Technology Harbin150001 China College of Mechanical and Electrical Engineering Nanjing University of Aeronautics and Astronautics Jiangsu Nanjing210016 China School of Electrical and Electronic Engineering Nanyang Technological University 639798 Singapore

SLAM plays a crucial role in automation tasks, such as warehouse logistics, healthcare robotics, and restaurant delivery. These scenes come with various challenges, including navigating around crowds of people, dealing with flying plastic bags that can temporarily blind sensors, and addressing reduced LiDAR density caused by cooking smoke. Such scenarios can result in over-degeneracy, causing the map to drift. To address this issue, this paper presents a multi-map LiDAR-inertial system (MM-LINS) for the first time. The front-end employs an iterated error state Kalman filter for state estimation and introduces a reliable evaluation strategy for degeneracy detection. If over-degeneracy is detected, the active map will be stored into sleeping maps. Subsequently, the system continuously attempts to construct new maps using a dynamic initialization method to ensure successful initialization upon leaving the over-degeneracy. Regarding the back-end, the Scan Context descriptor is utilized to detect inter-map similarity. Upon successful recognition of a sleeping map that shares a common region with the active map, the overlapping trajectory region is utilized to constrain the positional transformation near the edge of the prior map. In response to this, a constraint-enhanced map fusion strategy is proposed to achieve high-precision positional and mapping results. Experiments have been conducted separately on both public datasets that exhibited over-degenerate conditions and in real-world environments. These tests demonstrated the effectiveness of MM-LINS in over-degeneracy environment. Our codes are open-sourced on Github 1 Copyright © 2025, The Authors. All rights reserved.

关键词： Plastic containers

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Uapgo: Uncertainty-Aware Pose Graph Optimization for Lidar-Based Slam systems

SSRN

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SSRN 2024年

作者： Zhi, Tian Xu, Jie Ma, Yongxin Yu, Wenlu Liu, Shenglan Yuan, Shenghai College of Mechanical and Electrical Engineering Nanjing University of Aeronautics and Astronautics Jiangsu Nanjing210016 China School of Electrical and Electronic Engineering Nanyang Technological University Singapore639798 Singapore State Key Laboratory of Robotics and Systems Harbin Institute of Technology Harbin150001 China School of Mechanical Engineering Shandong University Jinan250061 China

Addressing uncertainty errors, although crucial, may sometimes be deprioritized in the optimization process ofLiDAR-based SLAM systems due to the inherent complexity of the task. The practice of applying uniform weights, which simplifies the uncertainty management, when incorporating factors can inadvertently degrade the pose graph optimization, particularly within complex environments. In response to this, we propose anuncertainty-aware pose graph optimization technique, along with an innovative keyframe selection strategy. We develop a model for estimating the covariance of relative pose transformations, utilizing frontend odometry output and the Huber robust kernel function. This model assigns weights based on the uncertainty error of pose transformations. Upon detection of a loop closure, the system optimizes keyframe poses, effectively reducing cumulative error. Our keyframe selection strategy takes into account the maximum eigenvalue of the translational component of pose covariance as an uncertainty measure. If this value surpasses a certain threshold, the pose is selected as a keyframe, thereby enhancing data precision and computational efficiency, and subsequently improving the SLAM system’s ability to handle uncertainty. Ablation studies validate our approach, demonstrating its effectiveness in enhancing performance, especially in complex environments and conditions of data degradation. Wealso provide the associated open-source code for further research. © 2024, The Authors. All rights reserved.

关键词： Eigenvalues and eigenfunctions

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Domain Consistency Representation Learning for Lifelong Person Re-Identification

arXiv

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arXiv 2024年

作者： Liu, Shiben Fan, Huijie Wang, Qiang Ren, Weihong Fan, Baojie Tang, Yandong The State Key Laboratory of Robotics Shenyang Institute of Automation Chinese Academy of Sciences Shenyang110016 China The University of Chinese Academy of Sciences Beijing100049 China The Key Laboratory of Manufacturing Industrial Integrated Shenyang University Shenyang110044 China The Harbin Institute of Technology Shenzhen518055 China The Department of Automation college Nanjing University of Posts and Telecommunications Nanjing210000 China

Lifelong person re-identification (LReID) exhibits a contradictory relationship between intra-domain discrimination and inter-domain gaps when learning from continuous data. Intra-domain discrimination focuses on individual nuances (i.e., clothing type, accessories, etc.), while inter-domain gaps emphasize domain consistency. Achieving a trade-off between maximizing intra-domain discrimination and minimizing inter-domain gaps is a crucial challenge for improving LReID performance. Most existing methods strive to reduce inter-domain gaps through knowledge distillation to maintain domain consistency. However, they often ignore intra-domain discrimination. To address this challenge, we propose a novel domain consistency representation learning (DCR) model that explores global and attribute-wise representations as a bridge to balance intra-domain discrimination and inter-domain gaps. At the intra-domain level, we explore the complementary relationship between global and attribute-wise representations to improve discrimination among similar identities. Excessive learning intra-domain discrimination can lead to catastrophic forgetting. We further develop an attribute-oriented anti-forgetting (AF) strategy that explores attribute-wise representations to enhance inter-domain consistency, and propose a knowledge consolidation (KC) strategy to facilitate knowledge transfer. Extensive experiments show that our DCR model achieves superior performance compared to state-of-the-art LReID methods. Our code will be available soon. © 2024, CC BY.

关键词： Contrastive Learning

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Locomotion Stability Analysis of Lower Extremity Augmentation Device

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Journal of Bionic Engineering 2019年第1期16卷 99-114页

作者： Likun Wang Chaofeng Chen Wei Dong Zhijiang Du Yi Shen Guangyu Zhao State Key Laboratory of Robotics and System Harbin Institute of TechnologyHarbin 150001China School of Astronautics Harbin Institute of TechnologyHarbin 150001China Weapon Equipment Research Institute China Ordnance Industries GroupBeijing 102202China

Stability is of great significance in the theoretical framework of biped ***-time control and walking patterns planning are on the premise that the robot works in the stable *** this paper,we address the crucial issue of the locomotion stability based on the modified Poincare return map and the hybrid *** akin to the traditional stability criteria,i.e.,the Zero Moment Point(ZMP)and the Center of Mass(CoM),the modified Poincare return map is more appropriate for both dynamic walking arid non-periodic ***,a novel high-level reinforcement learning methodology,so-called active PI2 CMA-ES,is proposed in this paper to plan the exoskeleton *** proposed learning methodology demonstrates that the locomotion of the exoskeleton is asymptotically stable according to the modified Poincare return map ***,the proposed learning methodology is tested by the Lower Extremity Augmentation Device(LEAD)and its effectiveness is verified by the experiments.

关键词： biped locomotion dynamic walking Dynamic Movement Primitives (DMP),stability exoskeleton bioinspiration

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Maximize the foot clearance for a hopping robotic leg considering motor saturation

arXiv

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arXiv 2021年

作者： Su, Juntong Jin, Bingchen Ye, Shusheng Ruan, Lecheng Sun, Caiming Ding, Ning Fu, Yili Luo, Jianwen Shenzhen518172 China Shenzhen518172 China Beijing100000 China State Key Laboratory of Robotics and System Harbin Institute of Technology Harbin150000 China

A hopping leg, no matter in legged animals or humans, usually behaves like a spring during the periodic hopping. Hopping like a spring is efficient and without the requirement of complicated control algorithms. Position and force control are two main methods to realize such a spring-like behaviour. The position control usually consumes the torque resources to ensure the position accuracy and compensate the tracking errors. In comparison, the force control strategy is able to maintain a high elasticity. Currently, the position and force control both leads to the discount of motor saturation ratio as well as the bandwidth of the control system, and thus attenuates the performance of the actuator. To augment the performance, this letter proposes a motor saturation strategy based on the force control to maximize the output torque of the actuator and realize the continuous hopping motion with natural dynamics. The proposed strategy is able to maximize the saturation ratio of motor and thus maximize the foot clearance of the single leg. The dynamics of the two-mass model is utilized to increase the force bandwidth and the performance of the actuator. A single leg with two degrees of freedom is designed as the experiment platform. The actuator consists of a powerful electric motor, a harmonic gear and encoder. The effectiveness of this method is verified through simulations and experiments using a robotic leg actuated by powerful high reduction ratio actuators. © 2021, CC BY-NC-ND.

关键词： Actuators

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SUBPIXEL EDGE LOCALIZATION BASED ON CONVERTED INTENSITY SUMMATION UNDER STABLE EDGE REGION

arXiv

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arXiv 2025年

作者： Yang, Yingyuan Liang, Guoyuan Wang, Xianwen Wang, Kaiming Wang, Can Wu, Xiaojun Shenzhen Institutes of Advanced Technology Chinese Academy of Sciences Shenzhen518055 China University of Chinese Academy of Sciences Beijing10049 China Guangdong Provincial Key Laboratory of Robotics and Intelligent System Shenzhen Institutes of Advanced Technology Chinese Academy of Sciences Shenzhen518055 China Guilin University of Technology Guilin541000 China School of Mechanical Engineering and Automation Harbin Institute of Technology at Shenzhen Shenzhen518055 China

To satisfy the rigorous requirements of precise edge detection in critical high-accuracy measurements, this article proposes a series of efficient approaches for localizing subpixel edge. In contrast to the fitting based methods, which consider pixel intensity as a sample value derived from a specific model. We take an innovative perspective by assuming that the intensity at the pixel level can be interpreted as a local integral mapping in the intensity model for subpixel localization. Consequently, we propose a straightforward subpixel edge localization method called Converted Intensity Summation (CIS). To address the limited robustness associated with focusing solely on the localization of individual edge points, a Stable Edge Region (SER) based algorithm is presented to alleviate local interference near edges. Given the observation that the consistency of edge statistics exists in the local region, the algorithm seeks correlated stable regions in the vicinity of edges to facilitate the acquisition of robust parameters and achieve higher precision positioning. In addition, an edge complement method based on extension-adjustment is also introduced to rectify the irregular edges through the efficient migration of SERs. A large number of experiments are conducted on both synthetic and real image datasets which cover common edge patterns as well as various real scenarios such as industrial PCB images, remote sensing and medical images. It is verified that CIS can achieve higher accuracy than the state-of-the-art method, while requiring less execution time. Moreover, by integrating SER into CIS, the proposed algorithm demonstrates excellent performance in further improving the anti-interference capability and positioning accuracy. Copyright © 2025, The Authors. All rights reserved.

关键词： Pixels

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Characterization of plasma discharge channel in EDM using photography and spectroscopy

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Procedia CIRP 2022年 113卷 184-189页

作者： Ling Qin Chen Liu Ruixue Zhang Ya-ou Zhang Xiaodong Yang Wansheng Zhao State Key Laboratory of Mechanical System and Vibration China School of Mechanical Engineering Shanghai Jiao Tong University 800 Dongchuan Road Shanghai 200240 China Department of Mechanical Engineering and Automation Harbin Institute of Technology Harbin 150001 China

The plasma discharge channel of electrical discharge machining (EDM) brings a temperature of several thousands of degrees Celsius into the gap between the anode and cathode, resulting in the material removal by means of melting and evaporating. To investigate the characteristics of the plasma discharge channel, high-speed imaging technology is adopted to observe the dimension of the plasma. A spectrometer is used to calibrate the temperature of the plasma as well. Then the particle-in-cell with Monte Carlo collision (PIC-MCC) simulation is conducted to analyze the variation and distribution of the plasma and heat flux. The experimental results demonstrate that the discharge channels’ morphology obtained is stable after a few microseconds of expansion after breakdown, and the diameter of discharge channel and the current density increases with the increase of discharge current. Besides, the emission intensity of plasma increases with the increase of electrical parameters. However, the temperature of plasma decreases after high current, which means debris particles make machining condition deteriorated. Finally, the simulation results demonstrate that despite the current density increases, the maximum heat flux at the center of electrode reduces rapidly with the expansion of the discharge channel. The distribution of heat flux upon electrode evolves towards "wider and flatter", leading to larger debris particles than exceptional size.

关键词： EDM plasma discharge channel spectrometer high-speed photography PIC-MCC

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Potential damage threats to downstream optics caused by Gaussian mitigation pits on rear KDP surface

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High Power Laser Science and Engineering 2020年第4期8卷 59-67页

作者： Hao Yang Jian Cheng Zhichao Liu Qi Liu Linjie Zhao Chao Tan Jian Wang Mingjun Chen State Key Laboratory of Robotics and System Harbin Institute of TechnologyHarbin 150001China Research Center of Laser Fusion China Academy of Engineering PhysicsMianyang 621900China

To determine whether a potassium dihydrogen phosphate(KDP)surface mitigated by micro-milling would potentially threaten downstream optics,we calculated the light-field modulation based on angular spectrum diffraction theory,and performed a laser damage test on downstream fused *** results showed that the downstream light intensification caused by a Gaussian mitigation pit of 800μm width and 10μm depth reached a peak value near the KDP rear surface,decreased sharply afterward,and eventually kept stable with the increase in downstream *** solved peak value of light intensification exceeded 6 in a range 8–19 mm downstream from the KDP rear surface,which is the most dangerous for downstream *** damage sites were then induced on the fused silica surface in subsequent laser damage *** the distance downstream was greater than 44 mm with a downstream light intensification of less than 3,there were no potential damage threats to downstream *** study proves that a mitigated KDP surface can cause laser damage to downstream optical components,to which attention should be paid in an actual *** this work,we find that the current manufacturing process and the mitigation index still need to be *** research methods and calculation models are also of great reference significance for related studies like optics mitigation and laser damage.

关键词： downstream threats KDP laser damage micro-milling mitigation

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Trackerless Freehand Ultrasound with Sequence Modelling and Auxiliary Transformation Over Past and Future Frames

Trackerless Freehand Ultrasound with Sequence Modelling and ...

引用

IEEE International Symposium on Biomedical Imaging

作者： Qi Li Ziyi Shen Qian Li Dean C Barratt Thomas Dowrick Matthew J Clarkson Tom Vercauteren Yipeng Hu Department of Medical Physics and Biomedical Engineering Centre for Medical Image Computing Wellcome/EPSRC Centre for Interventional and Surgical Sciences University College London London U.K. State Key Laboratory of Robotics and System Harbin Institute of Technology Harbin China School of Biomedical Engineering & Imaging Sciences King’s College London London U.K.

Three-dimensional (3D) freehand ultrasound (US) reconstruction without a tracker can be advantageous over its two-dimensional or tracked counterparts in many clinical applications. In this paper, we propose to estimate 3D spatial transformation between US frames from both past and future 2D images, using feed-forward and recurrent neural networks (RNNs). With the temporally available frames, a further multi-task learning algorithm is proposed to utilise a large number of auxiliary transformation-predicting tasks between them. Using more than 40,000 US frames acquired from 228 scans on 38 forearms of 19 volunteers in a volunteer study, the hold-out test performance is quantified by frame prediction accuracy, volume reconstruction overlap, accumulated tracking error and final drift, based on ground-truth from an optical tracker. The results show the importance of modelling the temporal-spatially correlated input frames as well as output transformations, with further improvement owing to additional past and/or future frames. The best performing model was associated with predicting transformation between moderately-spaced frames, with an interval of less than ten frames at 20 frames per second (fps). Little benefit was observed by adding frames more than one second away from the predicted transformation, with or without LSTM-based RNNs. Interestingly, with the proposed approach, explicit within-sequence loss that encourages consistency in composing transformations or minimises accumulated error may no longer be required. The implementation code and volunteer data 1 will be made publicly available ensuring reproducibility and further research.

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