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

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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Cover Image, Volume 41, Number 1, January 2024

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Journal of Field robotics 2023年第1期41卷

作者： Lefan Guo Gangfeng Liu Yongsheng Luo Peng Jiang Jie Zhao State Key Laboratory of Robotics and System Harbin Institute of Technology Harbin China MNR Key Laboratory for Polar Science Polar Research Institute of China Shanghai China

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A Modular Framework for Task-Agnostic, Energy Shaping Control of Lower-Limb Exoskeletons

TechRxiv

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TechRxiv 2024年

作者： Lin, Jianping Thomas, Gray Cortright Divekar, Nikhil V. Peddinti, Vamsi Gregg, Robert D. State Key Laboratory of Mechanical System and Vibration School of Mechanical Engineering Shanghai Jiao Tong University Shanghai200240 China Department of Mechanical Engineering Texas A&M University College StationTX77843 United States Department of Robotics University of Michigan Ann ArborMI48109 United States Department of Electrical and Computer Engineering University of Michigan Ann ArborMI48109 United States

Various backdrivable lower-limb exoskeletons have demonstrated the electromechanical capability to assist volitional motions of able-bodied users and people with mild to moderate gait disorders, but there does not exist a control framework that can be deployed on any joint(s) to assist any activity of daily life in a provably stable manner. This paper presents the modular, multi-task optimal energy shaping (M-TOES) framework, which uses a convex, data-driven optimization to train an analytical control model to instantaneously estimate assistive joint torques across activities for any lower-limb exoskeleton joint configuration. The presented modular energy basis is sufficiently descriptive to fit normative human joint torques (given normative feedback from signals available to a given joint configuration) across sit-stand transitions, stair ascent/descent, ramp ascent/descent, and level walking at different speeds. We evaluated controllers for four joint configurations (unilateral/bilateral, hip/knee) of the modular M-BLUE exoskeleton on eight able-bodied users navigating a multi-activity course comprising the primary activities of daily life. The two unilateral conditions significantly lowered overall muscle activation across all tasks and subjects (p © 2024, CC BY-NC-SA.

关键词： Exoskeleton (robotics)

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Type Synthesis of Fully-isotropic 2T3R 5-DoF Hybrid Mechanisms

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Journal of the Chinese Society of Mechanical Engineers, Transactions of the Chinese Institute of Engineers, Series C/Chung-Kuo Chi Hsueh Kung Ch'eng Hsuebo Pao 2019年第3期40卷 307-314页

作者： Zhang, Hong Zhou, Hui Qin, Youlei Ge, Shuyi Wang, Kun Cao, Yi School of Mechanical Engineering Jiangnan University Wuxi214122 China State Key Laboratory of Mechanical System and Vibration Shanghai200240 China State Key Laboratory of Robotics and System Harbin150080 China Jiangsu Key Laboratory of Advanced Food Manufacturing Equipment and Technology Wuxi214122 China

In mechanical design, it is necessary to synthesize the mechanism,especially for the fully-isotropic hybrid mechanisms (HMs). This article proposes a simple but very effective approach for fully-isotropic HMs by means of GF set theory. firstly, a type synthesis method for HMs is simply presented, especially, the option standard of the input motion joint and the steps for the integration of the branches are given which provide the theoretical foundations for the integration of the type structure of completely isotropic HMs. Secondly, the process of type synthesis for fully-isotropic HMs is described in detail. To corroborate the usefulness of the proposed method for fully-isotropic HMs, type synthesis of fully-isotropic 2T3R 5-Degree-0f-Freedom (DoF) HMs is illustrated with example, where T denotes translation and R denotes rotation. Finally, the forward displacement analysis of a synthesized 2T3R fully-isotropic HM is carried out. The expression of the Jacobian matrix is deduced, it shows that the Jacobian matrix of the synthesized fully-isotropic HM is a 5×5 identity matrix throughout the entire workspace validating the fully-isotropic feature of the HM and the effectiveness of the type of composite approach for fully-isotropic HMs. © 2019, Chinese Mechanical Engineering Society. All right reserved.

关键词： Jacobian matrices

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Simulation Platform for Autonomous Aerial Manipulation in Dynamic Environments

Simulation Platform for Autonomous Aerial Manipulation in Dy...

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IEEE International Conference on robotics and Biomimetics

作者： Fengyu Quan Huisheng Huang Hongjie Zeng Haoyao Chen Yunhui Liu State Key Laboratory of Robotics and System Harbin Institute of Technology Shenzhen China Chinese University of Hong Kong Hong Kong P. R. China

ISBN: (纸本)9781665405362

The aerial manipulator (AM) is a systematic operational robotic platform in high standard on algorithm robustness. Directly deploying the algorithms to the practical system will take numerous trial and error costs and even cause destructive results. In this paper, a new modular simulation platform is designed to evaluate aerial manipulation related algorithms before deploying. In addition, to realize a fully autonomous aerial grasping, a series of algorithm modules consisting a complete workflow are designed and integrated in the simulation platform, including perception, planning and control modules. This framework empowers the AM to autonomously grasp remote targets without colliding with surrounding obstacles relying only on on-board sensors. Benefiting from its modular design, this software architecture can be easily extended with additional algorithms. Finally, several simulations are performed to verify the effectiveness of the proposed system.

关键词： systematics Software architecture Heuristic algorithms Biological system modeling Software algorithms Grasping Sensors

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Shape Optimization of Soft Pneumatic Bellows for High Energy Density

Shape Optimization of Soft Pneumatic Bellows for High Energy...

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

作者： Yunpeng Miao Feifei Chen State Key Laboratory of Mechanical System and Vibration Shanghai Jiao Tong University Robotics Institute School of Mechanical Engineering Shanghai Jiao Tong University Shanghai China

ISBN: (纸本)9781665431545

Pneumatic bellows can perform extending or contracting and output certain forces at the same time. However, after many years of development, there are few detailed shape design of soft bellows, which leads to relatively low energy density and hinders miniaturization of soft robotic systems. In this paper, to explore the design space, linear bellows are parameterized by variables concerning the cross section and lateral profile with sinusoid functions. Then, a fast finite element analysis script is developed to evaluate the mechanical behavior of bellows under different parameter sets. With the maximal radius ballooning strain constrained below 0.1, the optimal design is obtained with the axial strain up to 0.74, blocking force up to 228.7 N, and volumetric energy density up to 6549.7 J/m 3 . Besides, we also adopt the idea of modular design which makes this soft bellow easy to be integrated. The developed soft pneumatic bellows are promising for use in scenarios where compact soft robots are expected.

关键词： Bellows Mechatronics Shape Machine vision Soft robotics Space exploration Finite element analysis

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Multi-Parameter Optimization for a Robust RGB-D SLAM system

Multi-Parameter Optimization for a Robust RGB-D SLAM System

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IEEE International Conference on robotics and Automation (ICRA)

作者： Yizhao Wang Xiaoxiao Zhu Guohan He Qixin Cao State Key Laboratory of Mechanical System and Vibration Shanghai Jiao Tong University Shanghai China Institute of Medical Robotics Shanghai Jiao Tong University Shanghai China

SLAM systems can retrieve their metric scales and depth information using RGB-D cameras. However, limited by the sensing range and objects structure, RGB-D cameras can not always work well, resulting in failures sometimes. In this work, we present initialization and localization methods based on maximum-a-posteriori estimation. Our system endows monocular keypoints with valid depth values and introduce them into bundle adjustment. Depth bias coefficient and scale factor are also optimized in the local window, obtaining robustness in large scale environments and long-running operations. The experimental results indicate that our system provides the best robustness compared with other excellent methods in the literature, being able to process the most challenging sequences in the TUM RGB-D dataset.

关键词： Location awareness Measurement Simultaneous localization and mapping Tracking Conferences Pose estimation Cameras

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A Biomimetic impedance controller for Robotic Hand Variable Stiffness Grasping

A Biomimetic impedance controller for Robotic Hand Variable ...

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IEEE International Conference on Mechatronics and Automation

作者： Bingchen Liu Li Jiang Shaowei Fan Chongyang Li State Key Laboratory of Robotics and System Harbin Institute of Technology Harbin China

ISBN: (数字)9781728164168

ISBN: (纸本)9781728164175

The accuracy of human hand grasp is due to many reasons, e.g. the feedbacks of force, temperature, pressure, and position, etc. It is impossible to mimic this complicated system for a robotic hand. Therefore, simplification of the robotic control system with relative accurate operations is necessary. In this study, a biomimetic impedance controller was utilized on a robotic hand, where the control parameters were based on a biomechanical model of the human hand. The relationship between the grasp force and surface electromyography (sEMG) was measured, and the impedance of the joint was calculated through a series of dynamic vibration tests subsequently. The effectiveness of the biomimetic impedance controller is verified through human operating the robotic hand reproducing a variety of grasping tasks.

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Research on Structural Optimization Design and Trajectory Planning of Frog-inspired Robot

Research on Structural Optimization Design and Trajectory Pl...

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International Conference on Information Science and Technology (ICIST)

作者： He Zhang Jizhuang Fan Bowen Yuan Gangfeng Liu State Key Laboratory of Robotics and System Harbin Institute of Technology Harbin China

ISBN: (数字)9781728155586

ISBN: (纸本)9781728155593

The marine environment is complex and dangerous, underwater robots instead of humans to explore the ocean have become an inevitable trend of future technological development. Frogs are explosive and flexible when they swim, these advantages provide important ideas for designing underwater robots. Based on the previous research results of our team, a new generation of frog inspired robot is designed in this paper. While optimizing structural performance, we add two degrees of freedom to the hip joint. The motion space of the hind limb is obtained through kinematics analysis, combining the observation data of wild frogs, the three-dimensional trajectory of the frog-inspired robot in each motion phase is fitted, and the acceleration planning is focused on the propulsion phase. Finally, the rationality of the trajectory planning and the reliability of the structure are verified through experiments.

关键词： Trajectory Planning Hip Robot kinematics Acceleration

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A Kind of Kinematics Modeling of 2 DOFs Notched Continuum Manipulator

A Kind of Kinematics Modeling of 2 DOFs Notched Continuum Ma...

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International Conference on Information Science and Control Engineering (ICISCE)

作者： Xiaolong Wang Zhiyuan Yan Haodong Wang Yongzhuo Gao Zhijiang Du State Key Laboratory of Robotics and System Harbin Institute of Technology Harbin China

It’s difficult for traditional rigid manipulators to complete relevant operations in the single port laparoscopic. The notched continuum manipulator owns the features of flexibility and biocompatibility which can make it possible applied in the single port laparoscopic. A kinematics modeling similar to the constant-curvature approximations is proposed in this paper. It can be utilized to describe the mapping relationship between the length change value of two driven wires and the end position. This method simplifies the complexity of kinematic modeling. And it makes the control method of the continuum manipulator easier to achieve as well. The accuracy of the model has been verified by the prototype.

关键词： Laparoscopes Information science Control engineering Shape Wires Force feedback Prototypes

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