检索结果-内蒙古大学图书馆

Configuration synthesis of planar folded and common overconstrained spatial rectangular pyramid deployable truss units

引用

Chinese Journal of Aeronautics 2019年第7期32卷 1772-1787页

作者： Hui YANG Hongwei GUO Yan WANG Rongqiang LIU Zongquan DENG College of Electrical Engineering and Automation Anhui UniversityHefei230601China State Key Laboratory Robotics and System Harbin Institute of TechnologyHarbin150001China China Electronics Technology Group Corporation No.38Research Hefei230088China

Compared with non-overconstrained deployable units, overconstrained deployable units are widely used in space missions for their higher stiffness characteristics. Besides the performance of a three-step topological structural analysis and design of the rectangular pyramid deployable truss unit(PDTU), conducting a structural synthesis of an overconstrained deployable unit requires the determination of the relative position and direction of each kinematic axis. The structural synthesis of an overconstrained deployable unit is investigated based on screw theory and its topological structure. The possible overconstrained cases of the rectangular PDTUs are analyzed, and corresponding screw expressions are obtained. Thus, the rectangular PDTUs, which can be folded into a plane, are synthesized systemically, and a series of overconstrained rectangular PDTUs is obtained. Furthermore, the feasibility of the folded and deployed motions under one degree of freedom for those deployable units is verified in dynamical simulation by using ADAMS 2010.

关键词： Assembly SAR antenna Common overconstraint Deployable truss structure Screw theory Structural synthesis

来源：评论

学校读者我要写书评

暂无评论

Review of surgical robotic systems for keyhole and endoscopic procedures:state of the art and perspectives

引用

Frontiers of Medicine 2020年第4期14卷 382-403页

作者： Yuyang Chen Shu’an Zhang Zhonghao Wu Bo Yang Qingquan Luo Kai Xu State Key Laboratory of Mechanical System and Vibration School of Mechanical EngineeringShanghai Jiao Tong UniversityShanghai 200240China RII Lab(Lab of Robotics Innovation and Intervention) UM-SJTU Joint InstituteShanghai Jiao Tong UniversityShanghai 200240China Department of Urology Shanghai Changhai Hospitalthe Second Military Medical UniversityShanghai 200433China Shanghai Lung Cancer Center Shanghai Chest HospitalShanghai Jiao Tong UniversityShanghai 200030China

Minimally invasive surgery,including laparoscopic and thoracoscopic procedures,benefits patients in terms of improved postoperative outcomes and short recovery *** challenges in hand–eye coordination and manipulation dexterity during the aforementioned procedures have inspired an enormous wave of developments on surgical robotic systems to assist keyhole and endoscopic procedures in the past *** paper presents a systematic review of the state-of-the-art systems,picturing a detailed landscape of the system configurations,actuation schemes,and control approaches of the existing surgical robotic systems for keyhole and endoscopic *** development challenges and future perspectives are discussed in depth to point out the need for new enabling technologies and inspire future researches.

关键词： surgical robots keyhole surgery endoscopic surgery

来源：评论

学校读者我要写书评

暂无评论

Time-Optimal Control of Underactuated Wheeled Inverted Pendulum Vehicles Along Specified Paths

Time-Optimal Control of Underactuated Wheeled Inverted Pendu...

引用

International Conference on Advanced robotics and Mechatronics (ICARM)

作者： Yigao Ning Ming Yue Zenan Lin School of Automotive Engineering Dalian University of Technology Dalian China State Key Laboratory of Robotics and System Harbin Institute of Technology Harbin China

ISBN: (数字)9781728164793

ISBN: (纸本)9781728164809

This study proposes a time-optimal control method for a wheeled inverted pendulum (WIP) vehicle under specified paths. Firstly, the given path is described with a parametric form, and the kinematic model, velocity constraint and acceleration constraint are all parameterized with a same parameter as the geometric path. Meanwhile, the stabilization constraint of vehicle body is also formulated through the kinematic coupling relationship to take the underactuated characteristic into full consideration. Next, the time-optimal trajectory is constructed by a sequence of minimum acceleration and maximum acceleration trajectories based on phase-plane analysis, and the optimality is illustrated through rigorous analysis. Finally, a time-optimal trajectory tracking controller is designed for the WIP vehicle to realize the minimum-time motion, and numerical simulation results validate the effectiveness of the proposed method.

关键词： Acceleration Trajectory Mechatronics Kinematics Mobile robots Trajectory tracking

来源：评论

学校读者我要写书评

暂无评论

Nonequilibrium Effects on Rapid Directional Solidification Microstructures During Additive Manufacturing: A Quantitative Phase Field Study

SSRN

引用

SSRN 2024年

作者： Li, Leiji Xiao, Fei Li, Zhu He, Shiyu Liu, Yang Cai, Xiaorong Hou, Ruihang Zhou, Ying Zuo, Shungui Zhang, Chongfeng Gao, Jinzhong Shen, Xiaopeng Zhu, Tianchi Gu, Yijia Jin, Xuejun State Key Lab of Metal Matrix Composite School of Materials Science and Engineering Shanghai Jiao Tong University 800 Dong Chuan Road Shanghai200240 China Institute of Medical Robotics Shanghai Jiao Tong University Shanghai200240 China National Key Laboratory of Aerospace Mechanism Aerospace System Engineering Shanghai 3805 Jin Du Road Shanghai201108 China Department of Materials Science and Engineering Missouri University of Science and Technology RollaMO65409 United States National Engineering Research Center of Advanced Magnetic Resonance Technologies for Diagnosis and Therapy School of Materials Science and Engineering Shanghai Jiao Tong University 800 Dong Chuan Road Shanghai200240 China Department of Materials Science and Engineering Graduate School of Engineering Osaka University 2-1 Yamada-oka Osaka Suita565-0871 Japan Shanghai Key Laboratory of Materials Laser Processing and Modification China

Fusion-based metal additive manufacturing (AM) is a technology that builds objects layer by layer, with rapid solidification referring to the quick transition of material from liquid to solid. During this process, solute trapping, a nonequilibrium effect characterized by velocity-dependent partition coefficient, significantly influences microstructure kinetics, morphology, and phase formation. This study utilizes the latest quantitative phase field (PF) model to systematically investigate the solute trapping, solute drag, and their effects on pattern formation during rapid solidification at velocities relevant to AM, in both one and two dimensions. Under different temperature gradients and pulling velocities, we observed that the growth mode transits from planar to cellular to dendritic, then back to cellular, and finally to planar, which is consistent with classic solidification theory. A solidification microstructure selection map is constructed based on PF simulations. Furthermore, we compared primary dendritic/cell spacing calculated by the PF model with theoretical models. The simulated morphologies and arm spacing showed good agreement with experimental observations for Al-4Si and Ti-20Nb alloys during rapid solidification. These results demonstrate the potential of the PF model for predicting and controlling microstructure formation under rapid solidification conditions in the melt pool of AM processes. © 2024, The Authors. All rights reserved.

关键词： Morphology

来源：评论

学校读者我要写书评

暂无评论

A Novel Path Planning Approach with Bidirectional A* Algorithm Based on Road Characteristics

A Novel Path Planning Approach with Bidirectional A* Algorit...

引用

International Conference on Mechatronics and Machine Vision in Practice (M2VIP)

作者： Weihua Li Bowen Chen Pengpeng Li Xuewen Geng Jianfeng Wang State Key Laboratory of Robotics and System Harbin Institute of Technology Harbin China School of Automotive Engineering Harbin Institute of Technology-Weihai Weihai China SGCC Smart Energy and Electric Transportation Technology Innovation Center (Suzhou) Co.Ltd. Suzhou China

ISBN: (纸本)9781665431545

The global path planning of a traditional A* algorithm is investigated to obtain the shortest path, which considers only the straight-line distance between grids without considering the effects of road slope and road resistance on the path distance and the energy consumption for ground vehicles. The heuristic function of shortest path based on road slope and the heuristic function of minimum energy consumption based on road resistance coefficient are respectively developed in this paper. Combining the two improvements, a novel comprehensive heuristic function is proposed in this paper. Through the distribution of weight coefficients between the shortest path and the minimum energy consumption, one more reasonable path can be obtained. In addition, a bidirectional A* search algorithm is also applied. The case studies validate that the improved A* search algorithm in this paper can generate a more reasonable path considering the distance and the energy consumption.

关键词： Resistance Energy consumption Mechatronics Roads Heuristic algorithms Machine vision Focusing

来源：评论

学校读者我要写书评

暂无评论

A novel approach for flexible manipulator conducting screwing task based on robot–environment contact classification

引用

Proceedings of the Institution of Mechanical Engineers, Part C: Journal of Mechanical Engineering Science 2019年第8期235卷 1357 - 1367页

作者： Qi Zhang Zongwu Xie Yang Liu Xiaoyu Zhao Yikun Gu Hong Liu State Key Laboratory of Robotics and System Harbin Institute of Technology Harbin China

Bolt screwing assembly task is a crucial part for robot fine manipulation. For widely applied flexible joints robot with six-dimensional force/torque sensor, data collected could not be seen as the contact force since it consists of internal force caused by deformation of the manipulator joints. Force analysis and geometric analysis could not be applied to judge the relative pose between robot end-effector and the environment. To this end, logistic regression method was used to classify the contact state by force signals. Besides, the criterion that bolt has entered the thread hole is also significant, while a boundary condition was proposed to solve this problem. A bolt screwing experiment was conducted to evaluate the proposed strategy, and the results demonstrate the effectiveness of the contact state classification and the boundary condition for judging the bolt entering the thread hole.

关键词： Flexible manipulator logistic regression classification bolt screwing assembly

来源：评论

学校读者我要写书评

暂无评论

Research on impedance control of flexible joint space manipulator on-orbit servicing

Research on impedance control of flexible joint space manipu...

引用

2019 IEEE International Conference on robotics and Biomimetics, ROBIO 2019

作者： Liu, Dongyu Liu, Hong Liu, Yechao Li, Zhiqi China Academy of Space Technology Institute of Manned Spacecraft System Engineering Beijing China Harbin Institute of Technology State Key Laboratory of Robotics and System Harbin Heilongjiang Province China

ISBN: (纸本)9781728163215

In this paper, the positional accuracy and contact force index requirements of the manipulator are analyzed according to the tolerance index of the space manipulator screwing. An position-based in Cartesian space impedance control strategy based on friction identification and compensation is proposed. By using joint friction torque compensation to improve the system control precision and setting the desired Cartesian position of the manipulator end point to control the contact force, this strategy solves the contradiction between the positional accuracy index and the contact force index requirement of manipulator during contact operating. The control algorithm is designed based on the system dynamics model, and the stability analysis of the control algorithm is given. The correctness of the control strategy is verified by simulation and on-orbit implementation. China's space manipulator has successfully completed the actual on-orbit servicing mission based on impedance control for the first time. © 2019 IEEE.

关键词： Friction

来源：评论

学校读者我要写书评

暂无评论

GRNet: Gridding Residual Network for Dense Point Cloud Completion 16th

GRNet: Gridding Residual Network for Dense Point Cloud Compl...

引用

16th European Conference on Computer Vision, ECCV 2020

作者： Xie, Haozhe Yao, Hongxun Zhou, Shangchen Mao, Jiageng Zhang, Shengping Sun, Wenxiu State Key Laboratory of Robotics and System Harbin Institute of Technology Harbin China Faculty of Computing Harbin Institute of Technology Harbin China SenseTime Research Shenzhen China Nanyang Technological University Singapore Singapore The Chinese University of Hong Kong Hong Kong SAR China Peng Cheng Laboratory Shenzhen China SenseTime Research Hong Kong SAR China

ISBN: (纸本)9783030585440

Estimating the complete 3D point cloud from an incomplete one is a key problem in many vision and robotics applications. Mainstream methods (e.g., PCN and TopNet) use Multi-layer Perceptrons (MLPs) to directly process point clouds, which may cause the loss of details because the structural and context of point clouds are not fully considered. To solve this problem, we introduce 3D grids as intermediate representations to regularize unordered point clouds and propose a novel Gridding Residual Network (GRNet) for point cloud completion. In particular, we devise two novel differentiable layers, named Gridding and Gridding Reverse, to convert between point clouds and 3D grids without losing structural information. We also present the differentiable Cubic Feature Sampling layer to extract features of neighboring points, which preserves context information. In addition, we design a new loss function, namely Gridding Loss, to calculate the L1 distance between the 3D grids of the predicted and ground truth point clouds, which is helpful to recover details. Experimental results indicate that the proposed GRNet performs favorably against state-of-the-art methods on the ShapeNet, Completion3D, and KITTI benchmarks. © 2020, Springer Nature Switzerland AG.

关键词： Computer vision

来源：评论

学校读者我要写书评

暂无评论

Static Force Analysis of Foot of Electrically Driven Heavy-Duty Six-Legged Robot under Tripod Gait

引用

Chinese Journal of Mechanical Engineering 2018年第4期31卷 58-72页

作者： Zhen Liu Hong-Chao Zhuang Hai-Bo Gao Zong-Quan Deng Liang Ding State Key Laboratory of Robotics and System Harbin Institute of Technology College of Mechanical Engineering Tianjin University of Technology and Education

The electrically driven six-legged robot with high carrying capacity is an indispensable equipment for planetary exploration, but it hinders its practicability because of its low efficiency of carrying energy. Meanwhile, its load capacity also affects its application range. To reduce the power consumption, increase the load to mass ratio, and improve the stability of robot, the relationship between the walking modes and the forces of feet under the tripod gait are researched for an electrically driven heavy-duty six-legged robot. Based on the configuration characteristics of electrically driven heavy-duty six-legged, the typical walking modes of robot are analyzed. The mathematical models of the normal forces of feet are respectively established under the tripod gait of typical walking modes. According to the MATLAB software, the variable tendency charts are respectively gained for the normal forces of feet. The walking experiments under the typical tripod gaits are implemented for the prototype of electrically driven heavy-duty six-legged robot. The variable tendencies of maximum normal forces of feet are acquired. The comparison results show that the theoretical and experimental data are in the same trend. The walking modes which are most available to realize the average force of distribution of each foot are confirmed. The proposed method of analyzing the relationship between the walking modes and the forces of feet can quickly determine the optimal walking mode and gait parameters under the average distribution of foot force, which is propitious to develop the excellent heavy-duty multi-legged robots with the lower power consumption, larger load to mass ratio, and higher stability.

关键词： Electrically driven Heavy-duty six-legged robot Tripod gait Force of foot Walking mode

来源：评论

学校读者我要写书评

暂无评论

A visual calibration method of monocular camera and pan-tilt for mobile robots

A visual calibration method of monocular camera and pan-tilt...

引用

2019 IEEE International Conference on Real-Time Computing and robotics, RCAR 2019

作者： Sun, Jingwen Zhao, Lijun Wang, Ke Zhao, Yujia Meng, Xiangbo Mao, Chuwei Wang, Jiancheng State Key Laboratory of Robotics and System Harbin Institute of Technology Harbin China School of Electrical Engineering Automation Harbin Institute of Technology Harbin China

ISBN: (纸本)9781728137261

In the competition of 'RoboMaster', the robot, a mobile platform with a two-axis pan-tilt and a barrel, needs to shoot the target by launching a projectile. In order to detect and shoot the target automatically, we develop a visual system with a monocular camera mounted on the chassis. Based on some target detection algorithms, the target's 3D pose in the camera coordinate system is obtained. As the launching mechanism of the robot is on the two-axis pan-tilt, it demands to further obtain target's pose in the pan-tilt coordinate system to achieve precise shooting. Therefore, how to obtain the relative position between the camera coordinate system and the pan-tilt coordinate system is the main problem in our research. We propose a fast and effective method for the relative position calibration between the camera and two-axis pan-tilt based on specular reflection. We utilize a plane mirror to reflect the laser pointer light path mounted on the barrel. Then, the camera calibration method is applied to obtain the rotation matrix between the camera coordinate system and the world coordinate system. We finally verify the effectiveness of our method through experiments and achieve the first place in the competition. © 2019 IEEE.

关键词： Calibration

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：