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A geometric method based on space arc for pose-configuration simultaneous planning of segmented hyper-redundant manipulators

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Science China(Technological Sciences) 2021年第11期64卷 2389-2407页

作者： HU ZhongHua YUAN Han XU WenFu YANG TaiWei LIU TianLiang LIANG Bin School of Mechanical Engineering and Automation Harbin Institute of TechnologyShenzhen 518055China State Key Laboratory^of Robotics and System Harbin Institute of TechnologyHarbin 150001China Department of Automation Tsinghua UniversityBeijing 100084China

A segmented hyper-redundant manipulator can perform complicated operation tasks in a confined space due to its high flexibility and dexterity. However, the trajectory planning in a narrow space and obstacles environment is very challenging for the manipulator. In this paper, we propose a geometry method to simultaneously plan the end-effector pose and manipulator’s configuration. Firstly, the geometries of each segment are described by an inscribed arc(IA) and a circumscribed arc(CA). Then,the whole kinematics chain is considered as an inscribed curve(IC) or a circumscribed curve(CC) which are composed of multiple IAs or CAs. Furthermore, the IC and CC of the manipulator are divided into multiple spatial single-arc and double-arc groups according to requirements. The pose-configuration simultaneous planning is realized by the spatial single-arc/double-arc modeling and joints angles solving. By numerical iteration, the spatial arcs’ parameters are determined according to desired pose and boundary condition of obstacle avoidance. The angles of joints are analytically solved when the above parameters are known. Finally, a narrow space detection task is simulated and experimented respectively. The results verify the proposed method.

关键词： segmented hyper-redundant manipulator pose-configuration simultaneous planning spatial arc modeling obstacle avoidance geometric planning

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Research on Surface Defect Detection technology of Long-Distance and Long-Span FAST Cable

Research on Surface Defect Detection Technology of Long-Dist...

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Mechatronics and robotics Engineering (ICMRE), International Conference on

作者： Xin Tong Xuehe Zhang Gangfeng Liu Changle Li Jie Zhao State Key Laboratory of Robotics and System Harbin Institute of Technology Harbin China

Aiming at the problems of large cable span, small number of defect samples and complex background environment in the FAST cable defect detection task, a set of real-time defect detection algorithms based on convolutional neural network is proposed to realize the accurate location and classification of defects. It can achieve a good detection effect for defects with multiple angles and sizes, especially suitable for medium and long distances. The algorithm is verified on the dataset, and its recognition accuracy can reach 91.7%. Equipped on the hardware inference platform, it fully meets the efficiency and accuracy requirements of FAST cable inspection site, can be used in actual cable quality inspection tasks, and can be widely promoted to real-time defect detection of various high-altitude hanging cables.

关键词： Mechatronics Simulation Inspection Real-time systems Inference algorithms Hardware Convolutional neural networks

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A Kinematic Decoupling Whole-body Control Method for a Mobile Humanoid Upper Body Robot

A Kinematic Decoupling Whole-body Control Method for a Mobil...

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Frontiers of robotics and Software Engineering (FRSE), International Conference on

作者： Fengjia Ju Hongzhe Jin Jie Zhao State Key Laboratory of Robotics and System Harbin Institute of Technology Harbin China

The mobile humanoid upper body robot combines the humanoid upper body robot with the mobile platform. It has high redundancy and can complete complex tasks. However, coupling joints, including the waist joints and the mobile platform, exist in the configuration of the robot. During the task execution, the motion of the end-effectors on the dual arms are not independent, but interfere with each other through the motion of the waist and the mobile platform. Therefore, we need to decouple the waist and mobile platform from the dual arms. Based on the pseudo-inverse method of the redundant manipulators, we consider the motion of the coupling joints as a disturbance term and propose a kinematic decoupling whole-body control method. The method realizes the decoupling and cooperation of dual arms, avoids the interference of the inverse kinematics model of the dual arms, and fully releases the application potential of the high redundancy. The decoupling method allows the waist joints and the mobile platform to move randomly without affecting the task operation at the end-effectors, and to further plan their movements separately in order to smooth the whole body motion. The simulations on the mobile humanoid upper body robot verifies our method.

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Nonlocal Huygens'meta-lens for high-qualityfactor spin-multiplexing imaging

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Light(Science & Applications) 2025年第3期14卷 695-702页

作者： Jin Yao Yubin Fan Yunhui Gao Rong Lin Zhihui Wang Mu Ku Chen Shumin Xiao Din Ping Tsai Department of Electrical Engineering City University of Hong KongKowloonHong Kong SARChina Centre for Biosystems Neuroscienceand NanotechnologyCity University of Hong KongKowloonHong Kong SARChina State Key Laboratory of Terahertz and Milimeter Waves City University of Hong KongKowloonHong Kong SARChina State Key Laboratory on Tunable Laser Technology Ministry of Industry and Information Technology Key Lab of Micro-Nano Optoelectronic Information SystemShenzhen Graduate SchoolHarbin Institute of TechnologyShenzhen 518055China Pengcheng Laboratory ShenzhenChina

Combining bright-feld and edge-enhanced imaging affords an effective avenue for extracting complex morphological information from objects,which is particularly beneficial for biological *** metalenses present promising candidates for achieving this ***,current multiplexing meta-lenses lack spectral modulation,and crosstalk between different wavelengths hampers the imaging quality,especilly for biological samples requiring precise wavelength ***,we experimentally demonstrate the nonlocal Huygens'meta-lens for high-quality-factor spin-multiplexing ***-bound states in the continuum(q-BlCs)are excited to provide a high quality factor of 90 and incident-angle *** generalized Kerker condition,driven by Fano-like interactions between q-BIC and in-plane Mie resonances,breaks the radiation symmetry,resulting in a transmission peak with a geometric phase for polarization-converted light,while unconverted light exhibits a transmission dip without a geometric *** polarization conversion efficiency of 65%is achieved,accompanied by a minimal unconverted value,surpassing the theoretical limit of traditional thin nonlocal *** these effects,the output polarization-converted state exhibits an efficient wavelengthselective focusing phase *** unconverted counterpart serves as an effective spatial frequency filter based on incident-angular dispersion,passing high-frequency edge ***-field imaging and edge detection are thus presented under two output spin *** work provides a versatile framework for nonlocal metasurfaces,boosting biomedical imaging and sensing applications.

关键词： nonlocal Huygensmeta lens biological imagingmultiplexing metalenses bright field imaging edge enhanced imaging high quality factor spin multiplexing imaging extracting complex morphological information biological samples spectral modulationand

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A Light Space Manipulator with High Load-to-Weight Ratio: system Development and Compliance Control

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Space(Science & technology) 2021年第1期2021卷 107-118页

作者： Zhiwei Wu Yongting Chen Wenfu Xu The School of Mechanical Engineering and Automation Harbin Institute of TechnologyShenzhen 518055China The State Key Laboratory of Robotics and System Harbin Institute of TechnologyHarbin 150001China

In order to meet the requirements of the space environment for the lightweight and load capacity of the manipulator,this paper designs a lightweight space manipulator with a weight of 9.23 kg and a load of 2 *** adopts the EtherCAT communication protocol and has the characteristics of high load-to-weight *** order to achieve constant force tracking under the condition of unknown environmental parameters,an integral adaptive admittance control method is *** control law is expressed as a third-order linear system equation,the operating environment is equivalent to a spring model,and the control error transfer function is *** control performance under the step response is further *** simulation results show that the proposed integral adaptive admittance control method has better performance than the traditional *** has no steady-state error,overcomes the problems caused by nonlinear discrete compensation,and can facilitate analysis in the frequency domain,realize parameter optimization,and improve calculation accuracy.

关键词： overcome load EtherCAT

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Design and Implementation of Quasi-Direct-Drive Legs for a Frog-Like Jumping Robot

Design and Implementation of Quasi-Direct-Drive Legs for a F...

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Computer, Control and robotics (ICCCR), International Conference on

作者： Dong Zhihui Fan Jizhuang Du Qilong Zhao Jie State Key Laboratory of Robotics and System Harbin Institute of Technology Harbin China

This study aims to design and optimize a motor-driven frog-like jumping robot leg for efficient vertical jumps and multiple consecutive horizontal jumps. We have conducted bionic research on frog legs' structure and motion characteristics and further explored their motion mechanism, providing new ideas and methods for designing and manufacturing robots with high mobility and adaptability. First, our research team designed a robot leg prototype based on the frog's body structure, optimized the robot using computer-aided design software, and selected a suitable motor-driven actuator. Secondly, the weight reduction optimization of the robot body is carried out regarding material selection and topology optimization to improve the robot's maneuverability and jump height. Finally, after manufacturing the prototype of the robot legs, the robot is experimentally verified. The results show that the robot legs can achieve efficient vertical jumps (the maximum height is 1.40 meters, about 7.8 times the length of the leg link). It can also jump multiple times consecutively, which is significant for applying robots in dangerous environments, search and rescue, and other fields.

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Aerodynamic Analysis and Deployment Mechanism of A Foldable Mars Quadrotor

Aerodynamic Analysis and Deployment Mechanism of A Foldable ...

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IEEE International Conference on Mechatronics and Automation

作者： Kaijie Zhu Dewei Tang Qiquan Quan Kaiyi Wang Yachao Dong Zongquan Deng State Key Laboratory of Robotics and System Harbin Institute of Technology Harbin China

The Mars quadrotor is a vertical take-off and landing aerial platform developed to enhance the efficiency of Mars exploration. The four-blade rotor has a high thrust coefficient due to its high solidity, which enables the quadrotor to navigate the Martian atmospheric environment efficiently. This paper proposes a payload-carrying Mars quadrotor featuring four four-bladed rotors that can fold along the rotor arms. The computational fluid dynamics (CFD) method is employed to perform numerical hovering simulations, exploring the propulsion capability and aerodynamic efficiency of rotors with different diameters. The mass distribution and hovering time are estimated when the quadrotor consists of the rotors with the highest figure of merit. The results demonstrate that a larger rotor diameter of the quadrotor yields greater payload capacity and shorter hovering time. During the launch, the quadrotor is folded and constrained within an envelope to protect it from vibrations and shocks. A lifting mechanism with shape-constraint slides is utilized for quadrotor deployment.

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A Positioning Method Based on Kalman Filter for FAST Feed Support Cable Inspection Robot

A Positioning Method Based on Kalman Filter for FAST Feed Su...

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Mechatronics and robotics Engineering (ICMRE), International Conference on

作者： Xiangyu Sun Gangfeng Liu Xuehe Zhang Changle Li Jie Zhao State Key Laboratory of Robotics and System Harbin Institute of Technology Harbin China

In this paper, a positioning system developed for cable inspection robot system which works on feed support cables of Five-hundred-meter Aperture Spherical radio Telescope (FAST) is introduced. The positioning system consists of wheeled odometers and a Real-tme kinematic (RTK) based Global Navigation Satellite system (GNSS). Firstly, the cable with fixed ends and free suspension in the middle is modeled, and the influence of wind on the cable in FAST site is analyzed. Then, the data of the four odometers on the robot are processed, and the odometer information is fused with GNSS information through Kalman filtering. Then the best position estimation of the cable inspection robot is determined. A simulation is finally established to verify the proposed robot positioning method. The result shows that the method can work pretty well under the real working situation.

关键词： Vibrations Global navigation satellite system Analytical models Solid modeling Inspection Mathematical models Feeds

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Data Augmentation for Improving CNNs in Medical Image Classification

Data Augmentation for Improving CNNs in Medical Image Classi...

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6th International Conference on Intelligent Computing and Signal Processing (ICSP)

作者： Yi Ren Zengmin He Yang Deng Bo Huang State Key Laboratory of Robotics and System Harbin Institute of Technology Harbin China

Medical image is essential for physicians to diagnose diseases. And convolutional neural networks (CNNs) have gained momentum for computer-aided diagnosis (CAD) medical image. However, there are still challenges in CNNs related to a lack of data and class-imbalanced datasets. Data augmentation is utilized to address the issues mentioned above. In this study, the Pseudo-color enhancement algorithm (OCEAN and TWILIGHT), common linear transform, CLAHE enhancement, and K-means clustering algorithm were applied to pneumonia X-ray images for data augmentation. Thus, five processed datasets were finally obtained. The results indicated that five data-augmentation methods effectively improved the performance of CNNs for the pneumonia X-ray images binary classification detection, in which the CLAHE enhancement and OCEAN enhancement methods had the accuracy and F1 Score with 97.42%, 97.19%, and 97.42%, 98.36%, respectively. DenseNet121 showed the best classification performance of four CNNs utilized in this study, as evidenced by the area under the receiver operating characteristic (ROC) curves (AUC). To verify the generalizability of the two enhancement methods, CLAHE and OCEAN enhancement methods were applied to the Magnetic Resonance Imaging (MRI) dataset of Alzheimer's disease, which had the accuracy and F1 Score with 98.15% , 98.15%, and 97.22%, 97.68%, respectively. Therefore, these simple and efficient data-augmentation methods effectively improve the performance of CNNs for diagnosing medical image, which can provide theoretical reference for physicians to diagnose the above two diseases, and advance the application of clinical medicine.

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Structural Design and Experiment of a Small Wheel-legged Mobile Robot with Variable Configuration

Structural Design and Experiment of a Small Wheel-legged Mob...

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IEEE International Conference on Mechatronics and Automation

作者： Xiulong Cui Jizhuang Fan Zhihui Dong Yue Ou Jie Zhao The State Key Laboratory of Robotics and System Harbin Institute of Technology Harbin China

In this paper, we made an improved design on the traditional quadruped robot structure and developed a new small wheel-legged mobile robot structure. It has four legged configurations, which can be selected according to different situations, improving the mobility and operability of the robot. In wheeled mode, the robot can adjust its center of gravity according to actual needs. Including the rotational degree of freedom of the wheel, each leg has four degrees of freedom. Each leg adopts a series structure and moves the knee drive motor to the fuselage position using a parallel four-link mechanism and is symmetrically arranged with the hip drive motor. A wheel is installed at the end of the shank, and a DC brushless motor is built inside it, enabling the robot to have the function of wheeled motion. This article introduces the details of the wheel-legged robot, emphasizing the innovative design of the physical structure and the diversity of deformation. The forward kinematics was analyzed. Based on the full-elbow configuration (a type of legged configuration), a cycloidal motion optimization simulation was completed for the single leg structure. Simulation experiment has proven that the optimized robot’s single leg motion is smoother. Finally, we conducted a typical experiment using an embedded controller to control single leg motion. The experimental results verify that the optimized cycloidal motion of the robot meets the desired motion effect.

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