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Development of two-dimensional piezoelectric laser scanner with large steering angle and fast response characteristics

Development of two-dimensional piezoelectric laser scanner w...

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ASPEN/ASPE 2017 Spring Topical Meeting on Manufacture and Metrology of Structured and Freeform Surfaces for Functional Applications

作者： Kim, Ho-Sang Lee, Chan-Hee Lee, Won-Gi Lee, Dae-Hee Center for Robot and Manufacturing Technology Institute for Advanced Engineering Yongin Kyonggi-do Korea Republic of

We describe a two-dimensional piezoelectric laser scanner designed and tested to obtain the large steering angle of 1 degree and fast response characteristics with 200 Hz. To overcome the relatively small expansion capability of piezoelectric actuator, the displacement amplification mechanisms are employed to magnify the end tip of the lever which is connected to the 0.5" aluminum mirror. For fast response characteristics, several shapes of the displacement amplification mechanisms are proposed and their natural frequencies calculated by using finite element analysis technique. As a result of performance testing of hinge mechanisms by exciting the actuator, the resolution of the proposed piezoelectric scanner shows the excellent capability in beam steering. Also, the actual machining test of the proposed laser scanner in the burning paper are performed to show that it is capable of steering the laser beam in 1 degree and with frequency of 200 Hz.

关键词： Piezoelectric actuators

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Driving force synchronous control of redundantly actuated parallel manipulator

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Jisuanji Jicheng Zhizao Xitong/Computer Integrated Manufacturing Systems, CIMS 2018年第9期24卷 2140-2149页

作者： Liu, Xiaofei Yao, Jiantao Zhao, Yongsheng Key Laboratory of Advanced Forging and Stamping Technology and Science Ministry of Education Yanshan University Qinhuangdao066004 China Key Laboratory of Parallel Robot and Mechatronic System of Hebei Province Yanshan University Qinhuangdao066004 China

To improve the actuation coordination of redundantly actuated parallel manipulator, a novel model-based driving force synchronous control method was proposed. With 6PUS+UPU parallel manipulator as the research object, the dynamics model was deduced based on virtual work principle, and the coordination mechanism of driving force under scheduled motion was analyzed. On the basis of force-position hybrid actuation, a driving force synchronous control method was proposed, and the control algorithm was designed with coordination mechanism. Simulation and prototype experiment were used to verify the proposed control method. © 2018, Editorial Department of CIMS. All right reserved.

关键词： Manipulators

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Model-based Synchronous Control of Redundantly Actuated Parallel Manipulator with Neural Network

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Nongye Jixie Xuebao/Transactions of the Chinese Society for Agricultural Machinery 2018年第2期49卷 367-375页

Redundantly actuated parallel manipulator demands higher actuation coordination than the non-redundantly actuated one, thanks to its degree of actuation exceeding its degree of freedom. To improve the actuation coordination of redundantly actuated parallel manipulator, a novel model-based driving force synchronous control method with neural network was proposed. With 6PUS+UPU parallel manipulator as object, dynamic model was derived based on virtual work principle. To improve the actuation coordination of redundantly actuated parallel manipulator, a novel driving force synchronous control method was proposed on basis of force-position hybrid actuation. The synchronous control method was based on the driving force error of actuated joints and driving force adjustment was calculated by the synchronous controller. The synchronous controller was designed with neural network. What's more, the learning law of neural network controller was derived with manipulator's dynamic model to improve the learning efficiency. Model simulation and prototype experiment were carried out, and a performance comparison analysis with traditional force-position hybrid actuation method was made to verify the proposed control method. Comparison analysis revealed that, comparing with the traditional force-position hybrid actuation method, driving force synchronous control with neural network proposed could effectively improve the actuation coordination of redundantly actuated parallel manipulator. The results revealed that the synchronous control method reduced the driving force errors of whole manipulator by properly magnifying the control error of force actuated joint. © 2018, Chinese Society of Agricultural Machinery. All right reserved.

关键词： Dynamic models

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Effect of Rolling Reduction Rate on the Microstructure of Hot Rolling Stainless Steel Clad Plate 5

Effect of Rolling Reduction Rate on the Microstructure of Ho...

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2018 5th International Conference on advanced Composite Materials and Manufacturing Engineering, ACMME 2018

作者： Jin, Herong Zhang, Lei Yi, Yali Key Lab. of Advanced Forging and Stamping Technology and Science of Ministry of National Education Yanshan University Qinhuangdao066004 China Parallel Robot and Mechatronic System Laboratory of Hebei Province Yanshan University Qinhuangdao066004 China School of Mechanical Engineering Yanshan University Qinhuangdao066004 China

The macro-scale and meso-scale simulation models of stainless steel clad plate were established by DEFORM-3D. The multi-scale coupling simulations of clad plate with different rolling parameters were carried out. The seven pass hot rolling process of stainless steel clad plate was simulated by numerical simulation. By contrasting the vertical stress and the deformation resistance of cladding layer, the rolling reduction rate satisfying interface bonding was obtained. The grain distribution at the center of the substrate layer was analyzed and reasonable hot rolling reduction rates were selected considering their effects on the recrystallization volume percent and the grain size. The results show that the grain size decreases with the increase of reduction rate. However, too much reduction rate will decrease the rate of recrystallization volume percent and the refining effect of grain is not obvious. To ensure uniform grain size distribution, it is most reasonable to set the rolling temperature to 1150°C and the reduction rate to 50%. © Published under licence by IOP Publishing Ltd.

关键词： Stainless steel

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Dynamics analysis and simulation of a new 6-DOF lower limb rehabilitation robot

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IOP Conference Series: Materials Science and Engineering 2019年第6期490卷

作者： Hongbo Wang Musong Lin Yonggan Yan Guowei Liu Bowen Su Chaosheng Zhao Fuhao Wang Parallel Robot and Mechatronic System Laboratory of Hebei Province Yanshan University Qinhuangdao China Academy for Engineering & Technology Fudan University Shanghai China Key Laboratory of Advanced Forging & Stamping Technology and Science of Ministry of Education Yanshan University Qinhuangdao China

This paper proposes a new hybrid (parallel–serial) 6-DOF lower limb rehabilitation robot including two mechanical legs and an adjustable seat, which could train in sitting, lying and standing three postures. Each mechanical leg consists of hip joint, knee joint and ankle joint. The dynamics and DOF of the robot are analysed, and the result is verified by the software ADAMS. The result lay the foundation for prototype build in future.

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Inverse Dynamics Modeling of robotic Manipulator with Hierarchical Recurrent Network

Inverse Dynamics Modeling of Robotic Manipulator with Hierar...

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2019 IEEE/RSJ International Conference on Intelligent robots and Systems (IROS)

作者： Pengfei Sun Zhenzhou Shao Ying Qu Yong Guan Jindong Tan College of Information Engineering Beijing Advanced Innovation Center for Imaging Technology and Beijing Key Laboratory of Light Industrial Robot and Safety Verification Capital Normal University Beijing China Department of Electrical Engineering and Computer Science The University of Tennessee Knoxville TN USA Department of Mechanical Aerospace and Biomedical Engineering The University of Tennessee Knoxville TN USA

Inverse dynamics modeling is a critical problem for the computed-torque control of robotic manipulator. This paper presents a novel recurrent network based on the modified Simple Recurrent Unit (SRU) with hierarchical memory (SRU-HM), which is achieved by the nested SRU structure. In this way, it enables the capability to retain the long-term information in the distant past, compared with the conventional stacked structure. The hidden state of SRU is able to provide more complete information relevant to current prediction. Experimental results demonstrate that the proposed method can improve the accuracy of dynamics model greatly, and outperforms the state-of-the-art methods.

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Kinematic characteristics analysis and assembly application of a spatial symmetric 7R mechanism

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Hangkong Xuebao/Acta Aeronautica et Astronautica Sinica 2019年第4期40卷 422536页

作者： Han, Bo Xu, Yundou Yao, Jiantao Zheng, Dong Zhang, Shuo Zhao, Yongsheng Parallel Robot and Mechatronic System Laboratory of Hebei Province Yanshan University Qinhuangdao066004 China Key Laboratory of Advanced Forging & Stamping Technology and Science of Ministry of Education Yanshan University Qinhuangdao066004 China

A spatial symmetric 7R mechanism is proposed in this paper, constructing space deployable mechanisms. Firstly, the overall degree of freedom (DOF) is analyzed based on the screw constraint topology diagram, obtaining the variation of DOFs of the whole mechanism when the orientation of the joint axes changes. Then, the number and nature of DOFs of the motion output component in different orientations of the joint axes are analyzed based on the inverse screw theory. and the transient nature of the DOFs are analyzed. It is found that passive DOF and instantaneous DOF occurred in the arrangement of different joint axes orientations. Furthermore, the singular characteristics of the mechanism in different driving conditions are analyzed, obtaining the geometric conditions of the mechanism in the singular configuration under different driving conditions. Finally, a class of single-DOF polygonal pyramid-shaped space deployable mechanism is constructed by combining spatial symmetric 7R mechanisms with DOF at one. By setting the joint axes orientations, the mechanism yields a large folding rate, and due to its singular properties, it has good mechanical properties. Through the combination of a plurality of pyramid-shaped space deployable mechanisms, new large-scale space deployable mechanisms can be constructed, showing good application prospects in the aerospace field. © 2019, Press of Chinese Journal of Aeronautics. All right reserved.

关键词： Mechanisms

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Reducing MAC operation in convolutional neural network with sign prediction

Reducing MAC operation in convolutional neural network with ...

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International Conference on Information and Communication technology Convergence (ICTC)

作者： Jiho Chang Yoonsung Choi Taegyoung Lee Junhee Cho Intelligent Robot System Research Group Electronics and Telecommunications Research Institute Daejeon Korea School of Computing Korea Advanced Institute of Science and Technology Daejeon Korea

Due to recent researches on artificial neural net- work algorithms and machine learning, the accuracy of image recognition and natural language processing has increased to the level of human beings in specific fields. Especially, researches to improve the accuracy of algorithms are being actively conducted, and researches on hardware accelerators that implement such algorithms quickly and efficiently are actively under way. In order to utilize artificial intelligence reasoning ability as well as computing speed in mobile or embedded environment, it is necessary to reduce the power consumption and memory usage of artificial intelligence hardware. In this paper, we propose a algorithm to reduce the computational complexity in designing the CNN accelerator. We tried to reduce the MAC computation by encoding the inputs and predicting the sign of the MAC oper- ation. We confirmed the performance improvement by evaluating the sign predictor through the simulation results.

关键词： Neural networks Convolution Encoding Hardware Two dimensional displays Image coding Arrays

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High-Speed Active Release End-Effector Motions for Precise Positioning of Adhered Micro-Objects

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World Journal of Engineering and technology 2018年第1期6卷 81-103页

作者： Eunhye Kim Masaru Kojima Kazuto Kamiyama Mitsuhiro Horade Yasushi Mae Tatsuo Arai Department of Systems Innovation Graduate School of Engineering Science Osaka University Osaka Japan Beijing Advanced Innovation Center for Intelligent Robot and Systems Beijing Institute of Technology Beijing China The University of Electro-Communications Tokyo Japan

This paper presents a release method for micro-objects. To improve position accuracy after release, we propose 3D high-speed end-effector motions. The classical release task focuses on the detachment of a micro-object from an end-effector. The technique utilizes merely the vibration of the end-effector regardless of the pattern of movement. To release different sizes of micro- objects and place them precisely at the desired locations in both air and liquid media, in this paper, we propose high-speed motions by analyzing the adhesion force and movement of micro-objects after separation. To generate high end-effector acceleration, many researchers have applied simple vibration by using an additional actuator. However, in our research, 3D high-speed motion with apt amplitude is accomplished by using only a compact parallel mechanism. To verify the advantages of the proposed motion, we compare five motions, 1D motions (in X-, Y-, and Z-directions) and circular motions (clockwise and counterclockwise directions), by changing the frequency and amplitude of the end-effector. Experiments are conducted with different sizes of microbeads and NIH3T3 cells. From these experiments, we conclude that a counterclockwise circular motion can release the objects precisely in air, while 1D motion in the Y direction and two circular motions can detach the objects at the desired positions after release in a liquid environment.

关键词： Adhesion Force Vibration Generation Releasing Strategy Micro-Manipulation

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Real-time imaging of accelerated solid-liquid-gas reactions with nanobubbles

Research Square

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Research Square 2020年

作者： Wang, Wen Xu, Tao Chen, Jige Shangguan, Junyi Dong, Hui Ma, Huishu Zhang, Qiubo Bai, Tingting Guo, Zhirui Fang, Haiping Zheng, Haimei Sun, Litao SEU-FEI Nano-Pico Center Key Laboratory of MEMS of Ministry of Education Collaborative Innovation Center for Micro/Nano Fabrication Device and System Southeast University Nanjing210096 China Materials Sciences Division Lawrence Berkeley National Laboratory BerkeleyCA94720 United States Shanghai Synchrotron Radiation Facility Zhangjiang Laboratory Shanghai Advanced Research Institute Chinese Academy of Sciences Shanghai201204 China Department of Physics East China University of Science and Technology Shanghai200237 China Department of Materials Science and Engineering University of California BerkeleyCA94720 United States Shanghai Institute of Applied Physics Chinese Academy of Sciences Shanghai201800 China Key Laboratory of Welding Robot and Application Technology of Hunan Province Engineering Research Center of Complex Tracks Processing Technology Equipment of Ministry of Education Xiangtan University Xiangtan411105 China The Second Affiliated Hospital Key Laboratory for Aging & Disease Nanjing Medical University Nanjing210011 China

Solid-liquid-gas reactions are ubiquitous. An understanding of how gases influence the reactions at the nanoscale is significant for achieving the enhanced triple-phase reactions. Here, we report a real-time observation of the accelerated etching of gold nanorods with oxygen nanobubbles in aqueous hydrobromic acid using liquid cell transmission electron microscopy (TEM). Our observation reveals that when an oxygen nanobubble is close to a nanorod below the critical distance (~1nm), the local etching rate is significantly enhanced with over an order of magnitude faster. Molecular dynamics simulations results show that the strong attractive van der Waals interaction between the gold nanorod and oxygen molecules facilitates the transport of oxygen through the thin liquid layer to the gold surface and thus plays a crucial role in increasing the etching rate. This result sheds light on the rational design of solid-liquid-gas reactions for enhanced activities. © 2020, CC BY.

关键词： Molecular dynamics

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