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arXiv 2021年

作者： Yan, Shuaizheng Chen, Xingyu Wu, Zhengxing Tan, Min Yu, Junzhi The Laboratory of Cognitive and Decision Intelligence for Complex System Institute of Automation Chinese Academy of Sciences Beijing100190 China The Department of Mechanical Engineering Fuzhou University Fuzhou350000 China The School of Artificial Intelligence University of Chinese Academy of Sciences Beijing100049 China Xiaobing.AI Beijing100080 China The State Key Laboratory for Turbulence and Complex Systems Department of Advanced Manufacturing and Robotics College of Engineering Peking University Beijing100871 China

Robust vision restoration of underwater images remains a challenge. Owing to the lack of well-matched underwater and in-air images, unsupervised methods based on the cyclic generative adversarial framework have been widely investigated in recent years. However, when using an end-to-end unsupervised approach with only unpaired image data, mode collapse could occur, and the color correction of the restored images is usually poor. In this paper, we propose a data- and physics-driven unsupervised architecture to perform underwater image restoration from unpaired underwater and in-air images. For effective color correction and quality enhancement, an underwater image degeneration model must be explicitly constructed based on the optically unambiguous physics law. Thus, we employ the Jaffe-McGlamery degeneration theory to design a generator and use neural networks to model the process of underwater visual degeneration. Furthermore, we impose physical constraints on the scene depth and degeneration factors for backscattering estimation to avoid the vanishing gradient problem during the training of the hybrid physical-neural model. Experimental results show that the proposed method can be used to perform high-quality restoration of unconstrained underwater images without supervision. On multiple benchmarks, the proposed method outperforms several state-of-the-art supervised and unsupervised approaches. We demonstrate that our method yields encouraging results in real-world applications. © 2021, CC BY-NC-ND.

关键词： Image reconstruction

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A generalized model for predicting the optimal overlap rate and height of successive single-layer involved in laser metal deposition process based on the aspect ratio

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Optics & Laser Technology 2025年 191卷

作者： Enjie Dong Tingyu Chang Gan Li Ze Liu Liming Xia Linjie Zhao Junwen Lu Jiaxuan Chen Mingjun Chen Jian Cheng State Key Laboratory of Robotics and System Harbin Institute of Technology Harbin Heilongjiang 150001 China Department of Mechanical Engineering City University of Hong Kong Hong Kong China School of Mechanical Engineering and Automation Harbin Institute of Technology Shenzhen Guangdong 518055 China State Key Laboratory of Fluid Power and Mechatronic Systems Zhejiang University Hangzhou 310027 China Aircraft Repair & Overhaul Plant/Sichuan Province Engineering Technology Research Center of General Aircraft Maintenance Civil Aviation Flight University of China Guanghan 618307 China Zhengzhou Research Institute Harbin Institute of Technology Zhengzhou 450000 China

The surface flatness of single-layer islands deposition is essential for high-quality multi-layer component deposition and the stability of the Laser metal deposition (LMD) manufacturing process. The aspect ratio of single-track deposition and the overlap rate are critical factors influencing the flatness of single-layer island deposition. Existing methods for determining the optimal overlap rate, whether through experimental approaches or simplified recursive overlap models, still suffer from long development cycles and limited accuracy. In this study, a generalized, efficient and reliable model for predicting the optimal overlap rate only using the aspect ratio of the single-track deposition as the input parameter was developed after fully understanding the influence of the aspect ratio and overlap rate on the morphology, stacking effect and flatness of single-layer islands. Besides, a prediction model for the height of the single-layer island, based on the input parameters of the aspect ratio and the overlap rate has also been developed. Further, verification datasets from different experimental batches and materials were used to validate the accuracy and generalizability of the island height prediction model. The validation results indicated that the relative error between the predicted and actual values was less than 10%. The single-track aspect ratio can be directly used to guide the LMD multi-layer component deposition, regardless of the combination of powder and substrate materials, using these reliable and generalized prediction models for the optimal overlap rate and the island height developed in current study. The single-layer island deposition stage was completely eliminated, thereby significantly shorten the development cycle and reduce the cost of LMD process parameter development.

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An Approach for Multi-Objective Obstacle Avoidance Using Dynamic Occupancy Grid Map

An Approach for Multi-Objective Obstacle Avoidance Using Dyn...

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IEEE International Conference on Mechatronics and Automation

作者： Yanjie Liu Jiao Chen Xinyu Bai State Key Laboratory of Robotics and System Harbin Institute of Technology Harbin Heilongjiang Province China Sinopec International Business Co. Ltd. No. 22 North Chaoyang Gate Street Chaoyang District Beijing China

ISBN: (数字)9781728164168

ISBN: (纸本)9781728164175

Path planning in dynamic environments is an important guarantee for mobile robots to complete navigation tasks safely. However, human motion is unpredictable, changing its speed or direction arbitrarily, and traditional dynamic obstacle avoidance strategies based on object detection require massive computing resources in the prediction step, which reduces the real time characteristics of the system. To address this question, we propose a dynamic obstacle avoidance framework. It defines the environment as a random dynamic system by using dynamic grid maps, and obtains the velocity of multiple objects with low delay under GPU parallel acceleration calculations. Naturally, we introduce the relative velocity into the artificial potential field function. By expanding the data structure of costmaps, the dynamic grid map is effectively connected with the local obstacle avoidance algorithm. Our approach reduces the detour time of the robot and improves the system security.

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Enhancing wide-band trajectory tracking and finite-time control of Dielectric Elastomer Actuators using Nonsingular terminal sliding mode control scheme

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Mechatronics 2025年 109卷

作者： Kassim, Shakiru Olajide Zou, Jiang Behnamgol, Vahid Vaziri, Vahid Aphale, Sumeet S. Group School of Engineering University of Aberdeen ScotlandAB24 3UE United Kingdom The state Key Laboratory of Mechanical System and Vibration Shanghai Jiao Tong University Shanghai China The Robotics Institute School of Mechanical Engineering Shanghai Jiao Tong University Shanghai China Renewable Energy Research Centre Damavand Branch Islamic Azad University Tehran Iran Department of Electrical and Computer Engineering The Federal Polytechnic Damaturu Yobe State 620221 Nigeria

The utilization of Dielectric Elastomer Actuators (DEAs) in soft robotics is becoming increasingly popular due to their distinctive properties. However, controlling these actuators is challenging due to their nonlinear nature. This study addresses precise control of DEAs while minimizing nonlinear effects over a wide frequency range using a Sliding Mode Control (SMC) scheme. Traditional SMC approaches face two main issues: they do not ensure finite-time convergence during the sliding phase and compromise tracking accuracy due to approximations used to reduce chattering. This work presents a non-singular terminal sliding mode control combined with an enhanced boundary layer switching function to improve precision and finite-time stability. Using stability analysis, extensive MATLAB/SIMULINK simulations, and experimental validation on a conical DEA across diverse reference trajectories and its resilience against uncertainties, the proposed scheme demonstrates superior performance in trajectory tracking compared to PID-based and conventional SMC schemes. The results highlight the scheme's effectiveness in high-frequency trajectory tracking and its robustness to possible uncertainties and disturbances, offering a robust theoretical framework for dielectric elastomer actuator control and a promising approach for advancing soft robotic technologies. © 2025 The Authors

关键词： Intelligent robots

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Static modeling of a cross-spring flexure pivot with variable cross-section

Static modeling of a cross-spring flexure pivot with variabl...

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2018 International Symposium on Flexible Automation, ISFA 2018

作者： Chen, Yi Yang, Miao Wu, Dongmei Du, Zhijiang Dong, Wei State key laboratory of robotics and system Harbin Institute of Technology Harbin150080 China

A cross-spring flexure pivot with variable cross-section is studied in this paper, with the purpose of overcoming the disadvantages of the conventional cross-spring flexure pivot with uniform cross-section, such as axis drift and low axial stiffness. The work started with deducing the load-displacement relationship of a variable cross-section spring leaf by using the improved Awart’s beam constrained model. Then, a mechanical model of the proposed flexure pivot was established. The effectiveness of the deformation model is verified by finite element analysis. Finally, the proposed flexure pivot is compared with a conventional one, and the results show that the flexure pivot with variable cross-section has a higher rotational accuracy and a higher axial support stiffness. Copyright © 2018 by ISFA

关键词： Stiffness

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Development of a percussive ultrasonic drill driver 15

Development of a percussive ultrasonic drill driver

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15th IEEE International Conference on Mechatronics and Automation, ICMA 2018

作者： Quan, Qiquan Bulading, Aimaiti Zhao, Zhijun Bai, Deen Tang, Dewei Deng, Zongquan State Key Laboratory of Robotics and System Harbin Institute of Technology Harbin150001 China

ISBN: (纸本)9781538660720

Compared with the conventional drill driven by magnetic motors, percussive ultrasonic drill (PUD) shows advantages of small size, low power, low axial load, and lubrication free, making it available for the extraterrestrial rock sampling, especially for the minor planet with a weak gravitational field. The influence of the environment, load and aging of the components cause the resonance frequency of the PUD to drift, which causes the drilling efficiency of the PUD decreases drastically. During the PUD drilling rocks, the load imposed on the transducer is fickle. Though, the conventional frequency tracking control which tracking frequency by locking fixed phase does not perform well for the PUD. This paper presents a novel driving approach for the PUD, including the working principle of the PUD and a detailed design approach for the PUD driver. A driving circuit and a control algorithm were developed successfully. The experimental results show that the driver can drive the PUD effectively and make the drill work stably near the resonant frequency under different conditions. © 2018 IEEE.

关键词： Drills

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BTI Aging Monitoring based on SRAM Start-up Behavior

BTI Aging Monitoring based on SRAM Start-up Behavior

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Asian Test Symposium (ATS)

作者： Shengyu Duan Peng Wang Gaole Sai School of Computer Engineering and Science Shanghai University Shanghai China State Key Laboratory of Computer Architecture Institute of Computing Technology Chinese Academy of Sciences China State Key Laboratory of Mathematical Engineering and Advanced Computing Wuxi China Guangdong Provincial Key Lab of Robotics and Intelligent System Shenzhen Institutes of Advanced Technology Chinese Academy of Sciences China CAS Key Laboratory of Human-Machine Intelligence-Synergy Systems Shenzhen Institutes of Advanced Technology China

ISBN: (数字)9781728174679

ISBN: (纸本)9781728174686

Bias Temperature Instability (BTI) is one of the dominant CMOS aging mechanisms. It causes time-dependent variation, threatening circuit lifetime reliability. BTI-induced circuit errors are not detectable at the fabrication stage. On-line monitoring schemes are therefore necessary to capture the degradations during the operational time. Traditional aging monitoring techniques exhibit high implementation complexity and low stability. In this paper, we propose a BTI monitoring approach by simply tracking the start-up behavior of SRAM cells. SRAM is a widely used on-chip device in many applications. We study the impact of BTI for SRAM start-up values and age some cells in a manipulated manner. The BTI degradation is evaluated based on the number of SRAM cells starting with a certain value. This technique can be used to estimate the degradation for on-chip logic circuits without introducing additional circuitry, and thus has very low implementation complexity. We use an SRAM array with 1024 cells to estimate the degradations for multiple logic circuits, and show the average mean absolute percentage error as 8.48%. In addition, this technique is robust considering process, voltage and temperature variations.

关键词： Degradation Monitoring Logic circuits Transistors SRAM cells Aging system-on-chip

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Walking of biped robot with variable stiffness at the ankle joint

Walking of biped robot with variable stiffness at the ankle ...

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2019 IEEE International Conference on robotics and Biomimetics, ROBIO 2019

作者： Bi, Qing Liu, Yixiang Zang, Xizhe Song, Rui Wang, Haibin Li, Weimin Chinese Academy of Sciences Shandong Institute of Advanced Technology Jinan250001 China Shandong University School of Control Science and Engineering Jinan250061 China Harbin Institute of Technology State Key Laboratory of Robotics and System Harbin150080 China

ISBN: (纸本)9781728163215

Achieving versatile and efficient walking on biped robots is an important research objective. The impact between the foot and the ground has significant effects on the walking stability of biped robots. Research on human walking indicates that the joints in human lower limbs show different stiffness values in different phases of walking. Inspired by humans, this paper presents the realization of biped robot walking with variable stiffness at the ankle joint. A walking control scheme which combines PD control and variable impedance control is designed for the biped robot. Results of dynamic walking simulation verified that variable stiffness at the ankle joint could contribute to the improvement of walking stability and energy efficiency. © 2019 IEEE.

关键词： Energy efficiency

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Human-like Walking of a Biped Robot Actuated by Pneumatic Artificial Muscles and Springs*

Human-like Walking of a Biped Robot Actuated by Pneumatic Ar...

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IEEE International Conference on Automation Science and Engineering (CASE)

作者： Yixiang Liu Qing Bi Xizhe Zang Yibin Li School of Control Science and Engineering Shandong University Jinan China State Key Laboratory of Robotics and System Harbin Institute of Technology Harbin China Engineering Research Center of Intelligent Unmanned System Ministry of Education Jinan China Shandong Institute of Advanced Technology Chinese Academy of Sciences Jinan China

ISBN: (数字)9781728169040

ISBN: (纸本)9781728169057

Human walking gait is much more natural looking and energy efficient compared with biped robots. This paper presents a bio-inspired approach to realizing more human-like biped robotic walking. For this purpose, a biped robot actuated coordinately by pneumatic artificial muscles and springs is developed, capable of exploiting passive compliance of the mechanical system in locomotion. And a control scheme for human-like walking is designed based on finite state machine. Experiments show that the biped robot can walk stably on the treadmill even with some small obstacles. The realized gait has the important features of human walking, including heel strike and toe off, stretched knees, and variation in the height of the body's center of mass, which demonstrates the effectiveness of the proposed approach.

关键词： Conferences Automation Computer aided software engineering

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Optimal reaction control for the flexible base redundant manipulator system

Optimal reaction control for the flexible base redundant man...

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2019 IEEE International Conference on robotics and Biomimetics, ROBIO 2019

作者： Zhang, Yaowen Liu, Yechao Xie, Zongwu Moallem, Mehrdad Harbin Institute of Technology State Key Laboratory of Robotics and System Harbin Heilongjiang Province150006 China School of Mechatronic Systems Engineering Simon Fraser University VancouverBCV3T 0A3 Canada

ISBN: (纸本)9781728163215

The null space of the Jacobian for the redundant manipulators can be utilized to reach dual control goals and optimal effects. For the flexible base redundant manipulator system, the reaction force from the motion of the manipulator should be carefully handled while the end effector is tracking a desired trajectory. Different optimal goals are discussed, including the minimization of base deflection force/torque and base energy dissipation path. Considering the base reaction dynamic, the reaction force/torque is treated as the input of the base and the deflection energy is treated as the output, an integrated optimal goal is built and solved based on the LQR control to get an optimal feedback for the closed-loop dynamics. We discuss the different optimal goals and implement trough the redefined acceleration. We test the different control laws on the three- link manipulators which mounted on a three-DoF flexible base. Simulation results demonstrate that optimal goal in LQR form can be advantageous in terms of flexible base manipulator. © 2019 IEEE.

关键词： Redundant manipulators

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