检索结果-内蒙古大学图书馆

Classification of surface defects of strips based on invariable moment functions

Guangdian Gongcheng/Opto-Electronic Engineering 2008年第7期35卷 90-94页

作者： Zhang, Yuan Cheng, Wan-Sheng Zhao, Jie State Key Laboratory of Robotics and System Harbin Institute of Technology Harbin 150080 China

A method of feature extraction which is composed of invariable moment functions and Principal Component Analysis (PCA) is presented in order to recognize and classify the surface defects of strips. First, a 22-dimensional eigenvector which was invariable was extracted from images when the image was translated, scaled and rotated. And then, in order to improve the efficiency of classification, PCA was applied to reduce the dimension of the eigenvector. As a result, the 4-dimensional eigenvector was obtained. Finally, using these eigenvectors as input, weights and thresholds of the BP neural network were trained for the purpose of defect classification. Experimental results show that the average efficiency of the correct identification can reach 85%, and it's fit for the application for detection of surface defects of strips.

关键词：不变矩主成分分析法 BP 神经网络特征提取带钢表面缺陷

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Kinematics analysis and gait planning of a three-limb robot

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Beijing Youdian Daxue Xuebao/Journal of Beijing University of Posts and Telecommunications 2008年第1期31卷 57-61页

作者： Fan, Ji-Zhuang Zhu, Yan-He Zhao, Jie Cai, He-Gao State Key Laboratory of Robotics and System Harbin Institute of Technology Harbin 150001 China

Aiming at a three-limb robot with integration of its arm and leg mechanism, regarding robot's limb operating pattern as the special work process of its motion pattern, and translating kinematics analysis of the whole robot into the task of a kinematic combination of each limb acting as a standing or a swinging foot, the unification of kinematics model of the robot under circumstances of locomotion and operation is successfully realized. Working patterns of the three-limb robot in the state of both locomotion and operation are planned. A gait simulation of the three-limb robot is performed, it therefore justifies the previous theoretical analysis and lends a solid theoretical basis to the design of the robot controller in the future.

关键词： Robots

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Ground experimental system of space robot arm

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Harbin Gongye Daxue Xuebao/Journal of Harbin Institute of Technology 2008年第3期40卷 381-385页

作者： Shi, Shi-Cai Xie, Zong-Wu Zhu, Ying-Yuan Liu, Hong State Key Laboratory of Robotics and System Harbin Institute of Technology Harbin 150001 China

The ground experimental system was developed to verify the functions of the reconfigurable space robot arm. The system is designed based on air bearings. Without changing robot arm, the method can easily realize the 3D motions of the robot arm. Using this system, some functions of the space robot arm can be verified, such as total power consumption, kinematics and inverse kinematics arithmetic, and position and orientation accuracy in 3D space. Based on coordinate measuring machine (CMM), a new method easy to manipulate is put forward to measure the position and orientation accuracy. According to the method, a ground experimental system of 6-DOF space robot arm was developed. Through the system, the performances of the space robot arm are acquired, including total power consumption, position accuracy and orientation accuracy, all of which satisfy the technical requirements.

关键词： Robotic arms

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Biological Jumping Mechanism Analysis and Modeling for Frog Robot

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Journal of Bionic Engineering 2008年第3期5卷 181-188页

作者： Meng Wang Xizhe Zang Jizhuang Fan Jie Zhao Harbin Institute of Technology State Key Laboratory of Robotics and System Harbin 150001

This paper presents a mechanical model of jumping robot based on the biological mechanism analysis of frog. By biological observation and kinematic analysis the frog jump is divided into take-off phase, aerial phase and landing phase. We find the similar trajectories of hindlimb joints during jump, the important effect of foot during take-off and the role of forelimb in supporting the body. Based on the observation, the frog jump is simplified and a mechanical model is put forward. The robot leg is represented by a 4-bar spring/linkage mechanism model, which has three Degrees of Freedom (DOF) at hip joint and one DOF (passive) at tarsometatarsal joint on the foot. The shoulder and elbow joints each has one DOF for the balancing function of arm. The ground reaction force of the model is analyzed and compared with that of frog during take-off. The results show that the model has the same advantages of low likelihood of premature lift-off and high efficiency as the frog. Analysis results and the model can be employed to develop and control a robot capable of mimicking the jumping behavior of frog.

关键词： frog jump modality kinematic analysis mechanical model jumping robot

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key techniques of micromanipulation devices for MEMS assembling and packaging

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Jixie Gongcheng Xuebao/Chinese Journal of Mechanical Engineering 2008年第11期44卷 13-19页

作者： Sun, Lining Chen, Liguo Rong, Weibin Xie, Hui Liu, Yanjie State Key Laboratory of Robotics and System Harbin Institute of Technology Harbin 150080 China Robotics Institute Harbin Institute of Technology Harbin 150080 China

The characteristics of micro electro mechanical system (MEMS) assembling and packaging process are analyzed, and the development status of machining devices is given. According to the characteristics of MEMS industry development, the key techniques of MEMS assembling and packaging devices are described, including database of technological parameters, fast precision positioning, modular working tools, fast micro-vision, flexible clamping and automatic material handling techniques. The composition structure and working principle of an anodized bonding device for MEMS pressure sensor and a wire bonding device are introduced, and some experimental results are given. At last, the development trend of MEMS assembling and packaging techniques and devices are discussed.

关键词： Mechanics

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Singular perturbation control for flexible-joint manipulator based on flexibility compensation

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Jiqiren/Robot 2008年第5期30卷 460-466页

作者： Liu, Ye-Chao Jin, Ming-He Liu, Hong State Key Laboratory of Robotics and System Harbin Institute of Technology Harbin 150001 China Institute of Robotics and Mechatronics German Aerospace Center Munich 82230 Germany

Traditional singular perturbation approach can only be used in robot systems with weak joint flexibility. In order to solve this problem, a joint flexibility compensator is designed, which can greatly increase the equivalent joint stiffness, so the limitation of joint flexibility for singular perturbation approach is eliminated and the approach can be extended to the robot system with normal joint flexibility. Besides, an adaptive controller with projection algorithm as parameter estimation law is designed for the slow subsystem control and its asymptotical stability is proved. The control strategy can be applied conveniently in engineering without any joint flexibility limitation and does not need link acceleration or its differential signal. Finally, an experimental study on the flexible joint manipulator is executed and the results verify the validity and feasibility of the proposed strategy.

关键词： Flexible manipulators

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Research on a New Composite Ultrasonic Energy Transmission Mechanism with Parallel Structure

Research on a New Composite Ultrasonic Energy Transmission M...

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IEEE Conference on robotics, Automation and Mechatronics

作者： Yanjie Liu Lemin Zhang Dongcui Wang Yuetao Liu State Key Laboratory of Robotics and System Harbin Institute of Technology Harbin China

A composite two-dimension ultrasonic vibration system with parallel structure is presented in this paper for the wire bonding application. Compared with other conventional structures, this one uses the structure of the clamping beam, weakening the horizontal deflection stiffness, instead of the clamping ring, which weakens the coupling effects existing in most parallel structures. By means of the self-locking wedge, the piezoelectric ceramics are effectively preload. The length of the horn is optimized according to the relationship between the magnification ratio and the ratio of the horn length. Through the vibration characteristic analysis and FEA verification, it is proved that this parallel structure can increase the composite output amplitude of the ultrasonic horn and the density of ultrasonic energy, and can complete the bonding at a larger area range so that it will shorten the bonding time and improve the bonding efficiency.

关键词： Bonding Vibrations Welding Laboratories Clamps Robots Wire Frequency Flanges Optical coupling

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Energy harvesting with piezoelectric cantilever

Energy harvesting with piezoelectric cantilever

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IEEE Symposium (IUS) Ultrasonics

作者： Jiang-bo Yuan Tao Xie Wei-shan Chen State Key Laboratory of Robotics and System Harbin Institute of Technology Harbin China

Energy harvesting with the piezoelectric cantilever was studied under vibration environment. A theoretical model of piezoelectric cantilever was developed to determine the magnitude of power. The results predicted by the theoretical model were validated by the experimental data. Compared with the rectangular layer piezoelectric cantilever, the trapezoidal piezoelectric cantilever generated higher power with the same force and the volume of PZT. A maximal output power of about 24.2 mW can be obtained from the trapezoidal piezoelectric cantilever at the operating frequency of 130 Hz across a resistive load of 80kOmega with a cyclic stress of 1N.

关键词： Power generation Batteries Vibrations Power system modeling Stress Wireless sensor networks Capacitive sensors Voltage Equations Robots

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Design of a six legged wall-climbing robot

Design of a six legged wall-climbing robot

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IEEE Workshop on Advanced robotics and its Social Impacts, ARSO

作者： Wei Guo Ming Zhong Man-tian Li Yang Li State Key Laboratory of Robotics and System Harbin Institute of Technology Harbin Heilongjiang China

A new type of six legged wall-climbing robot with modular joints for the anti-terrorist field is proposed in this paper. It can move quickly and quietly with help of passive joints on its ankle and a silent vacuum generator. Design of the mobile system is first described. Then the analyses of the torque on each joint and the structure design of them, as well as the vacuum producer are presented in detail. Finally, the kinematics model of robot is also established.

关键词： Robots Joints Legged locomotion Robot sensing systems Vacuum systems Mobile communication Climbing robots

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Design and analysis of a cylindrical ultrasonic motor using bending transducer

Design and analysis of a cylindrical ultrasonic motor using ...

引用

SPAWDA Symposium on Piezoelectricity, Acoustic Waves, and Device Applications

作者： Wei-shan Chen Ying-xiang Liu Jun-kao Liu Sheng-jun Shi State Key Laboratory of Robotics and System Harbin Institute of Technology Harbin Heilongjiang China

A cylindrical ultrasonic motor using bending transducer was proposed in this paper. The stator components of proposed motor contain a cylinder and four bending transducers, and the four uniform bending transducers are set on the exterior surface of cylinder. The bending of transducers is excited by the longitudinal vibration of PZT ceramics. The four transducers are excited with two different groups of signal, and two bending vibrations are generated on the cylinder. When the amplitude of two bending vibrations is equal, and their phase difference on time and space is pi/2, a traveling wave is formed on the cylinder. Thus, an elliptical motion is achieved at the particle on the tooth. And the frictional force between rotor and stator is the driving force to realize the rotation motion of rotor. The PZT ceramics work with d33 mode, which have high electromechanical coupling efficiency and could improve the output characteristics. The working principle of proposed motor was analyzed. The cylinder and transducers were designed with FEM. The sensitive parameters of resonance frequency of transducer and cylinder were gained with modal analysis. The bending resonance frequency of transducers and cylinder were degenerated, and the motion trajectories of nodes on the teeth were analyzed. The result of transient analysis shows that the trajectory of node on the tooth is nearly an ellipse. The results of this paper could be useful in the development of this new type of motor.

关键词： Ultrasonic transducers Engine cylinders Teeth Stators Ceramics Rotors Resonance Resonant frequency Signal generators Space exploration

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