A set of three-dimensional profile detection system based on machine vision is designed for profile detection of parts on product line. This system mainly consists of a data acquisition module based on CCD (charge cou...
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A set of three-dimensional profile detection system based on machine vision is designed for profile detection of parts on product line. This system mainly consists of a data acquisition module based on CCD (charge coupled device), an embedded data processing module based on FPGA (field programmable gate array), a data transmitting module based on USB (universal serial bus), and an image display module based on OpenGL. The structure of this system is very compact, and it can reach higher resolution for parts moving in high speed on product line. Data processing module can run many arithmetics in it, therefore we can choose better. USB data transmitting interface offers faster data transmitting speed, and allows plugging and pulling device when the computer is powered on, so it avoids disadvantages of PCI (peripheral component interconnection) interface which is based on slot, and needs opening of the chassis. Display module based on VC shows detection result in graphic mode, it is more direct and conveniently realizes intercommunication between people and computer.
A new method which can segment gesture from general and complex backgrounds is introduced. First, this method deals the gesture picture which is get in the general background by convolute filter, and verifies clusteri...
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A new method which can segment gesture from general and complex backgrounds is introduced. First, this method deals the gesture picture which is get in the general background by convolute filter, and verifies clustering character of complexion, then by the complexion and geometry characters of the gestures, this method segments gestures from the backgrounds successfully. At last, by experiments of different backgrounds and eight different gestures, the validity of the method is verified, static state identify rate is 99%.
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-dimensi...
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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.
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 wh...
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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.
By integrating mean shift and particle filter, a new method for robotics visual tracking is proposed based on similarity distance. The method mainly depends on particle filter, and the particle number is proportional ...
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By integrating mean shift and particle filter, a new method for robotics visual tracking is proposed based on similarity distance. The method mainly depends on particle filter, and the particle number is proportional to the similarity distance. When the particle number exceeds the threshold, a small number of particles integrated with mean shift replace the traditional particle filter. After the tracking algorithm of each frame is finished, the similarity distance between the target and the model is calculated, which will adjust the number of the particles and determine whether the mean shift algorithm is called for the next frame. Moreover, the correlation coefficient between the particle number and the similarity distance is set through experiments. A frame tracking consumes about 5-10 ms. The experiment shows that our method can achieve accurate and real time tracking.
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 3...
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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.
Focusing on issues of map-distortion caused by accumulated error in mapping with only odometer and sonar sensors, new infrared location lags as absolute landmarks are introduced and build a topological map. Then a gri...
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Focusing on issues of map-distortion caused by accumulated error in mapping with only odometer and sonar sensors, new infrared location lags as absolute landmarks are introduced and build a topological map. Then a grid map is also built in the topological map and landmark information updates related incremental map on Bayesian theory. As result, the hybrid map reduces the accumulated error of sensors and improves the stability of the built map. Moreover, improved particle filter is used for robot localization, which based on the high weight adaptive algorithm can solve particle degradation of the traditional particle filters, because high weight particles and the surrounding space describe robot pose with high probability. Finally, results of experiments show that the map is effectively build based on grid map guided by absolute landmarks in 250 cm × 500 cm area, and improved particle filter can finish self-localization, error of which is less than 2 cm. Besides, localization test proves that improved particle is effective to solve degradation of particles.
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 a...
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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.
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 ...
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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.
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 equ...
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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.
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