检索结果-内蒙古大学图书馆

arXiv 2020年

作者： Jiao, Yanmei Wang, Yue Fu, Bo Tan, Qimeng Chen, Lei Wang, Minhang Huang, Shoudong Xiong, Rong State Key Laboratory of Industrial Control and Technology Zhejiang University Hangzhou China Beijing Key Laboratory of Intelligent Space Robotic System Technology and Applications Beijing Institute of Spacecraft System Engineering Beijing China Application Lab Huawei Incorporated Company China University of Technology Sydney Australia

Map based visual inertial localization is a crucial step to reduce the drift in state estimation of mobile robots. The underlying problem for localization is to estimate the pose from a set of 3D-2D feature correspondences, of which the main challenge is the presence of outliers, especially in changing environment. In this paper, we propose a robust solution based on efficient global optimization of the consensus maximization problem, which is insensitive to high percentage of outliers. We first introduce translation invariant measurements (TIMs) for both points and lines to decouple the consensus maximization problem into rotation and translation subproblems, allowing for a two-stage solver with reduced search space. Then we show that (i) the rotation can be estimated by minimizing TIMs using only 1-dimensional branch-and-bound (BnB), (ii) the translation can be estimated by running 1-dimensional search for each of the three axes with prioritized progressive voting. Compared with the popular randomized solver, our solver achieves deterministic global convergence without requiring an initial value. Furthermore, ours is exponentially faster compared with existing BnB based methods. Finally, our experiments on both simulation and real-world datasets demonstrate that the proposed method gives accurate pose estimation even in the presence of 90% outliers (only 2 inliers). Copyright © 2020, The Authors. All rights reserved.

关键词： Statistics

来源：评论

学校读者我要写书评

暂无评论

Combine Neural Radiance Fields in Different Reference Coordinates

Combine Neural Radiance Fields in Different Reference Coordi...

引用

Chinese Automation Congress (CAC)

作者： Weili Zhang Zhongheng Li Yu Guo Fei Wang Institute of Artificial Intelligence and Robotics Xi'an Jiaotong University Xi'an China Beijing Key Laboratory of Intelligent Space Robotic Systems Technology and Applications Beijing Institute of Spacecraft System Engineering Beijing China

Neural Radiance Fields (NeRF) leverage deep learning networks to restore high-quality implicit representations of 3D scenes from 2D images, surpassing traditional texture mapping in rendering quality. Typically, reconstructed images by NeRF exist in a reference coordinate system, necessitating consideration of each surface's information in a single shot. Overlapping parts in adjacent images are addressed by obtaining the camera pose through sparse COLMAP reconstruction. However, occluded regions, caused by contact with support surfaces, pose challenges for complete reconstruction. To address this, we propose a scene fusion algorithm based on NeRF, facilitating the amalgamation of neural radiance fields under different reference coordinate systems. This reduces data requirements and shooting conditions, enhancing the implicit 3D reconstruction of real objects. By estimating the translation and rotation relationship between image capture angles and the NeRF model, we fuse neural radiance fields in distinct reference coordinate systems, completing object surface information. Evaluation is conducted on both NeRF synthetic dataset and real objects.

关键词：

来源：评论

学校读者我要写书评

暂无评论

Formulation and verification to invalidation of the error evaluation for coordinate transformation by euclidean distance between markers

Formulation and verification to invalidation of the error ev...

引用

2015 IEEE 12th International Conference on Electronic Measurement & Instruments

作者： Tan Qimeng Sun Yikun Gao Sheng Chen Lei Wei Qingqing Bai Mei Beijing Key Laboratory of Intelligent Space Robotic System Technology and Applications Beijing Institute of Spacecraft System Engineering Beijing Special Engineering Design and Research Institute

Spatial markers can be used to not only complete coordinate transformation between two or more different Cartesian coordinate systems, but also to provide the error evaluation of the above transformation. On the one hand, a group of transforming markers is responsible for accurate parameters i.e. rotation matrix and translation vector;on the other hand, a group of checking markers can be used to quantify the accuracy of the results between coordinate transformation by Euclidean distance between markers. In this article, an invalidation of the error evaluation for coordinate transformation by relative Euclidean distance has been concluded and proven that the indexes are always constant because of an invariant group of checking markers, independent of the other group checking markers.

关键词： error evaluation coordinate transformation Euclidean distance between markers formulation

来源：评论

学校读者我要写书评

暂无评论

Design and Analysis of a Flying-crawling Spherical Robot for Multi-mode Movement

Design and Analysis of a Flying-crawling Spherical Robot for...

引用

IEEE International Conference on robotics and Biomimetics

作者： Pengfei Lu Kun Xu Xilun Ding Shuiqing Jiang Zixin Tang Yaobing Wang Robotics Institute of School of Mechanical Engineering and Automation Beihang University Beijing China Beijing Key Laboratory of Intelligent Space Robotic Systems Technology and Applications Beijing Institute of Spacecraft System Engineering Beijing China

A novel spherical robot named flying-crawling spherical robot is designed in this paper. It can fly or roll on ground with its single rotor and eight tail fins. When its limbs stretch out it can crawl on the supporting surface. Besides, with its limbs the robot can realize carrying objects, landing on uneven ground and walking on the supporting surface. Dynamic model of the robot in flight mode is established and the motion characteristics are analyzed. A PID control system is designed to enable the robot to achieve stable flight. Trot gait planning of the robot is given and a PID controller is designed for tail fins assistant in crawling mode. Corresponding simulations are carried out and the simulation results verify the proposed methods.

关键词：

来源：评论

学校读者我要写书评

暂无评论

Compact isolators and waveguides for flexural waves in plates

Compact isolators and waveguides for flexural waves in plate...

引用

第八届国际振动工程会议

作者： Yunhao Zhang Guangyuan Su Hao Zhou Bing Li Yongquan Liu State Key Laboratory for Strength and Vibration of Mechanical Structures School of Aerospace EngineeringXi'an Jiaotong University Beijing Key Laboratory of Intelligent Space Robotic Systems Technology and Applications Beijing Institute of Spacecraft System EngineeringChina Academy of Space Technology School of Aeronautics Northwestern Polytechnical University

Manipulation of flexural waves in plates has attracted extensive attention for vibration isolation and structural health monitoring. However, existing methods are difficult to be applied in practical engineering due to their bulky size, complex structure, and damage to the overall carrying capacity. In this work, we introduce a different way to steer flexural waves in plates to realize arbitrary isolators and waveguides without fabrication limitations and destruction of *** to appropriate impedance mismatch, periodic and sparse array of subwavelength and unitary units are preliminarily devised to isolate flexural waves, in a way of omnidirectional reflection. We then utilize this feature to realize various ultrathin isolators and waveguides. As verification, a circular isolator and a Z-shaped waveguide are designed and tested, respectively. They numerically and experimentally show excellent isolating and waveguiding performance. It opens up a range of opportunities to mitigating and guiding the energy in plate-like bearing structures.

关键词： Compact isolators and waveguides for flexural waves in plates

来源：评论

学校读者我要写书评

暂无评论

Dynamic Fluorescent Imaging for robotic Patch Clamp in vivo: Modeling and Control

Dynamic Fluorescent Imaging for Robotic Patch Clamp in vivo:...

引用

第42届中国控制会议

作者： Ruimin Li Jinyu Qiu Minghui Li Mingzhu Sun Xin Zhao Qili Zhao Institute of Robotics and Automatic Information System (IRAIS) Nankai University Tianjin Key Laboratory of Intelligent Robotic (tjKLIR) Nankai University Institute of Intelligence Technology and Robotic Systems Shenzhen Research Institute of Nankai University Beijing Advanced Innovation Center for Intelligent Robots and Systems Beijing Institute of Technology

Fluorescent imaging through fluorescent dye injection is the key technique for lighting the in vivo environment and localizing the target cell in it for patch clamp operation in vivo. At present, manual fluorescent imaging is usually a labor-intensive high-skill requisite work, significantly limiting the application of patch clamp operation in vivo. In this paper, a computational modeling of the diffusion process of the injected fluorescent dye is established using the commercial ANSYS Fluent software. Based on this model, the distribution of the mass fraction, proven to be linearly related to fluorescence intensity,was calculated to simulate the fluorescent field formed by fluorescent dye injection. Further, an ADRC controller was developed to generate feedback-controlled fluorescent fields. With the above model and controller, a mobile fluorescent field, and varying fluorescent field with constant mass fraction at the target position are generated to fulfill the requirement of in vivo environment observation, search and localization of the target cell in patch clamp operation, respectively. The above results prove the feasibility of ADRC-controlled dynamic fluorescent imaging in the patch clamp operation in vivo.

关键词：

来源：评论

学校读者我要写书评

暂无评论

Trajectory Planning Simulation of 3-DoF Parallel Wrist Mechanisms Based on SimMechanics

Trajectory Planning Simulation of 3-DoF Parallel Wrist Mecha...

引用

IEEE International Conference on Cyber technology in Automation, Control, and intelligent systems

作者： Chen Yang Liu Xin Wei Shimin Zhang Ying Huang Qineng School of Automation Beijing University of Posts and Telecommunications Beijing PR China Beijing Institute of Spacecraft System Engineering Beijing Key Laboratory of Intelligent Space Robotic System Technology and Applications Beijing PR China

ISBN: (数字)9781728107707

ISBN: (纸本)9781728107714

In this paper, the trajectory planning problem of a 3-DoF parallel wrist mechanism based on SimMechanics is proposed, which is a symmetric spherical 3-RRR parallel mechanism. The formulation of the inverse kinematics for the mechanism is firstly established by D-H matrix method, and the analytical solution is obtained. Then, the trajectory planning analysis of the mechanism is performed. Finally, the mechanism model is constructed based on the SimMechanics module of Matlab/Simulink, and the trajectory planning simulation of the mechanism is carried out. The simulation results agree well with the theoretical results, which indicate that the proposed method is feasible and convenient for the trajectory simulation of parallel mechanisms.

关键词： Kinematics Trajectory Conferences Automation intelligent systems Wrist

来源：评论

学校读者我要写书评

暂无评论

2-Entity RANSAC for robust visual localization in changing environment

2-Entity RANSAC for robust visual localization in changing e...

引用

2019 IEEE/RSJ International Conference on intelligent Robots and systems (IROS)

作者： Yanmei Jiao Yue Wang Bo Fu Xiaqing Ding Qimeng Tan Lei Chen Rong Xiong State Key Laboratory of Industrial Control and Technology Zhejiang University Hangzhou P.R. China Beijing Key Laboratory of Intelligent Space Robotic System Technology and Applications Beijing Institute of Spacecraft System Engineering Beijing P.R. China

Visual localization has attracted considerable attention due to its low-cost and stable sensor, which is desired in many applications, such as autonomous driving, inspection robots and unmanned aerial vehicles. However, current visual localization methods still struggle with environmental changes across weathers and seasons, as there is significant appearance variation between the map and the query image. The crucial challenge in this situation is that the percentage of outliers, i.e. incorrect feature matches, is high. In this paper, we derive minimal closed form solutions for 3D-2D localization with the aid of inertial measurements, using only 2 point matches or 1 point match and 1 line match. These solutions are further utilized in the proposed 2-entity RANSAC, which is more robust to outliers as both line and point features can be used simultaneously and the number of matches required for pose calculation is reduced. Furthermore, we introduce three feature sampling strategies with different advantages, enabling an automatic selection mechanism. With the mechanism, our 2-entity RANSAC can be adaptive to the environments with different distribution of feature types in different segments. Finally, we evaluate the method on both synthetic and real-world datasets, validating its performance and effectiveness in inter-session scenarios.

关键词：

来源：评论

学校读者我要写书评

暂无评论

Design of Planar Antenna and space Deployable Mast Based on a New 8r Origami Mechanism

SSRN

引用

SSRN 2024年

作者： Li, Ruixing Zhou, Guangwu Luo, Pei Zhao, Zhijun School of Aeronautics and Astronautics Sichuan University Chengdu610065 China Sichuan University Chengdu610065 China Beijing Key Laboratory of Intelligent Space Robotic Systems Technology and Applications Beijing Institute of Spacecraft System Engineering Beijing100092 China

The modular origami mechanism has great application prospect. In this paper, origami based on 8R mechanism is designed, the mechanism can be array. The kinematics of the 8R origami mechanism is analyzed, and the model reconstruction and motion bifurcation of the mechanism are found. There are two kinds of 8R mechanism that can satisfy the array: MMMN mechanism and NNNM mechanism. The motion bifurcation and model reconstruction of the mechanism are avoided in the design of thickness-plate origami. Taking into account the bearing capacity of the mechanism, the 8R mechanism of heavy plate origami is designed. The motion bifurcation and model reconstruction of the mechanism are avoided in the design of thickness-plate origami. The twisting direction of MMMN mechanism and NNNM mechanism is opposite. The planar antenna is designed using multiple MMMN mechanisms. The spread area of the planar antenna reaches 1350〖cm〗^2. NNNM mechanism and MMMN mechanism are used to design space deployable mast. The performance of planar antenna and space deployable mast is tested. The space deployable mast has a self-locking function in the unfolded state. The space deployable mast has a load-carrying capacity of more than 41N and requires only 6N folding force. © 2024, The Authors. All rights reserved.

关键词： Bifurcation (mathematics)

来源：评论

学校读者我要写书评

暂无评论

Near-Zero Thermal Mismatch Flexure Metamaterial with High-Resonant Frequency

SSRN

引用

SSRN 2022年

作者： Zhou, Hao Yu, Huabin Wang, Zhe Guo, Xiaogang Qi, Junfeng Zhang, Xiaoyu Fang, Daining Beijing Key Laboratory of Intelligent Space Robotic Systems Technology and Applications Beijing Institute of Spacecraft System Engineering China Academy of Space Technology No. 104 Youyi Road Beijing100094 China Beijing Key Laboratory of Lightweight Multi-functional Composite Materials and Structures Beijing Institute of Technology No. 5 Zhongguancun South Street Beijing100081 China Beijing Spacecrafts Manufacture Company Beijing100094 China

Heterogeneous mechanical metamaterials, especially fabricated by additive manufacturing techniques, have attracted attention in lightweight multifunctional material engineering. Near-zero thermal expansion materials play an important role in precision equipment. However, undesired thermal mismatch flexure distortion occurs when the precision equipment is mounted on the main load-bearing structures of spacecraft and the environmental temperature changes. The present study presents a near-zero thermal mismatch flexure metamaterial, including the design strategy inspired by plants with axisymmetric distributing anisotropic microstructures , the thermal deformation constitutive relation derived by the flexibility method, and the fabrication of this metamaterial sandwich structure by selective laser melting. Thermal deformation experiments demonstrate that the coefficient of thermal flexure reduces by 92.4% compared with traditional bi-material plates connected by screws. Mechanical vibration experiments demonstrate that the fundamental resonant frequency of this metamaterial sandwich structure can be as high as 956 Hz, which is 5.8 times larger than the common requirements of functional components for spacecraft to avoid mechanical resonance with the main structure during launch. The excellent thermal mismatch shape stability and high-resonant frequency properties make it a potential candidate for thermal geometric stable structures working in variable thermal and mechanical environments. © 2022, The Authors. All rights reserved.

关键词： Metamaterials

来源：评论

学校读者我要写书评

暂无评论

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案：

请选择收藏分类：

通借通还

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：