Time filter

Source Type

Xuan X.,Beijing Institute of Technology | Kun H.,Beijing Institute of Technology | Yang L.,China North Optical Electrical Technology Co. | Yuan L.,Beijing Institute of Technology
International Conference on Signal Processing Proceedings, ICSP | Year: 2017

Kalman filter has been extensively applied in vast areas. However, it is widely acknowledged that the performance of Kalman filter depends on the accuracy of priori information such as model structure, statistics information of process and observation noise. Obtaining the covariance matrix of process noise is difficult in some application scenarios. Considering such background, this paper presents a process noise estimation algorithm based on the noise observation sequence. By constructing a transform matrix and removing the state variables from the observation, the noise observation sequence can be established, through which the covariance matrix of process noise can be estimated. Comparing to conventional adaptive filter, this algorithm needs less calculation. Moreover, the noise estimation process is separated from Kalman filter thus ensures Kalman Filters independence and optimality. The simulation results show that the new algorithm can effectively estimate the process noise covariance, and remain uninfluenced by the initial condition. © 2016 IEEE.


An Y.,CAS Changchun Institute of Optics and Fine Mechanics and Physics | Song C.-P.,China North Optical electrical Technology Co. | Kuang R.-J.,TTS BoHai Machinery Dalian Co. | Jin G.,CAS Changchun Institute of Optics and Fine Mechanics and Physics
Proceedings of SPIE - The International Society for Optical Engineering | Year: 2010

The opto-electronic platform is the main equipment for aviation reconnaissance. It is a surveillance system with the function of search, recognition orientation and tracking by opto- electronic instruments. It is made up of opto-electronic instruments which are used to get high quality image , and stabilization tracking system to control stabilization and gesture of platform for exact tracking. The opto-electronic platform purpose is to achieve high quality image. Besides the impact of optic system, the image quality of the system is influenced greatly in the vibration environment. The research worked by Zhao peng which demonstrated the affection caused by angular vibration was worse than which caused by line vibration, and what was multiplied direct ratio with plane altitude. So it is necessary to design a new device which could be used widely and has good angular vibration isolation effect. According to the theory of parallelogram, the non-angular vibration device had been designed with spatial links, and the theory of non-angular vibration was analyzed. The three-dimensional model was set with UG, the analysis was done by ADAMS/vibration software. The acceleration and displacement response of the device in each direction was calculated by inspiriting it with sine wave of the acceleration in three directions, and the stiffness and damp were studied. All the work prove the design principle of the device is reasonable, and the device is adopted to keep the platform motion moving horizontally, at the meantime the device is good at isolating vibration in all directions. © 2010 SPIE.


Han L.,China North Optical electrical Technology Co. | Xu D.,CAS Institute of Automation | Zhang Y.,Chongqing University of Posts and Telecommunications
International Journal of Modelling, Identification and Control | Year: 2010

When a mobile robot navigates in an indoor environment using visual dead reckoning method, its positioning accuracy suffers from accumulated errors. Therefore, it is necessary to use landmarks to make correction. This paper investigates the natural landmark-based localisation for an indoor mobile robot. The landmarks used here include smoke detection sensors, speakers and lights on the ceiling that are widely available in many offices and corridors. To improve the real-time performance, the proposed method utilises global and local strategies to search lines on the ceiling, as well as the line fitting algorithm based on Hough transform and random sample consensus. The pose of mobile robot is estimated with visual dead reckoning method, and then corrected via PnP-based positioning method with natural landmarks. Experimental results verify the effectiveness of the proposed methods.


He J.-F.,Harbin Institute of Technology | Jin J.,Harbin Institute of Technology | Li B.-P.,China North Optical Electrical Technology Co. | Ye Z.-M.,Harbin Institute of Technology | Han J.-W.,Harbin Institute of Technology
Harbin Gongye Daxue Xuebao/Journal of Harbin Institute of Technology | Year: 2010

The hydraulically driven 6-DOF parallel Gough-Stewart mechanism was used as a motion simulator to simulate the real motions of carrier for testing firing control systems in laboratory. The bidirectional force/torque versus velocity interactions between mechanical dynamics system and its hydraulic driving system was explored to establish an integrated dynamic model. Then the couplings of pose outputs were presented and experimental results show that the couplings between these outputs will become more intense with the increase of motion frequency within natural frequency of the Gough-Stewart mechanism. Moreover, for the safety of the motion simulator, a simple criterion which only uses the lengths of legs instead of complicated and time-consuming method of condition number of Jacobian is proposed to distinguish singular area from the workspace. Amplitude and Phase Control (APC) and random wave duplication techniques were employed to greatly improve the simulation fidelity not only for sine waveform but for random waveform as well.


Lou Y.,China North Optical electrical Technology Co.
Proceedings of SPIE - The International Society for Optical Engineering | Year: 2010

The traditional contact measuring methods could not satisfy the current optical elements measuring requirements. Noncontact high precision measuring theory, principle and instrument of the surface form tolerances and central thickness for optical elements were studied in the paper. In comparison with other types of interferometers, such as Twyman-Green and Mach-Zehnder, a Fizeau interferometer has the advantages of having fewer optical components, greater accuracy, and is easier to use. Some relations among the 3/A(B/C), POWER/PV and N/ΔN were studied. The PV with POWER removed can be the reference number of ΔN. The chromatic longitudinal aberration of a special optical probe can be used for non-contanct central thickness measurement. © 2010 Copyright SPIE - The International Society for Optical Engineering.


Xu D.,Henan Polytechnic University | Wang D.,Henan Polytechnic University | Wang C.,Advanced Technology and Materials Co. | Han F.,China North Optical Electrical Technology Co.
Xiyou Jinshu/Chinese Journal of Rare Metals | Year: 2012

Three groups of PCB specimens were soldered by 96.5Sn3.0Ag0.5Cu lead-free solder with no-clean flux NCF and water-soluble flux WSF. Electrochemical migration tests were conducted to evaluate insulation reliability of flux residues. Results showed that the first group specimens soldered by NCF and the third group specimens soldered by WSF could meet the standard; insulation resistance of the second group specimens soldered by WSF dropped greatly and could not meet standard requirement, besides, dendrites were found under the magnification microscopy, and it illustrated that the existence of flux residues made the occurrence of electrochemical migration. The reasons of electrochemical migration were discussed, and it was considered that electrochemical migration was related to cleaning technology, ingredient of flux, solid content and acidity.


Zhao X.,China North Optical electrical Technology Co.
Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics) | Year: 2010

This paper proposed a new algorithm of face recognition using genetic algorithm for classification. After initialization, selection and recombination are executed in a loop until fitness criterion is reached. The fitness function is calculated by an information theoretical measure. Experimental results presented here show that the proposed face recognition algorithm is effective. © 2010 Springer-Verlag.


He J.-F.,Harbin Institute of Technology | Jiang H.-Z.,Harbin Institute of Technology | Tong Z.-Z.,Harbin Institute of Technology | Li B.-P.,China North Optical Electrical Technology Co Ltd | Han J.-W.,Harbin Institute of Technology
JVC/Journal of Vibration and Control | Year: 2012

In this paper, we study dynamic isotropy using natural frequency analysis for a class of symmetric spatial parallel mechanisms (SSPMs) with 2p (p≥3) struts. This kind of dynamic isotropy has been defined as the square roots of the eigenvalues of the equivalent mass-spring systems formed via the interactions between rigid-body mechanical systems and their driving systems. Analytic expressions for these eigenvalues are then derived in the task space, which is linearly dependent on p. Furthermore, a general compliance center was found for all the SSPMs in which the parallel mechanisms are fully decoupled. Based on the dynamically decoupling, then, dynamic isotropy for the SSPM is discussed which shows that though taking the inertial parameters into consideration, the SSPM can not attain complete dynamic isotropy and the optimal dynamic isotropy index is the quartic root of two. At the end of the paper, to demonstrate these results, an example is given. © 2011 The Author(s).


Zhao X.,China North Optical electrical Technology Co.
2010 International Conference on Measuring Technology and Mechatronics Automation, ICMTMA 2010 | Year: 2010

This paper proposed a new algorithm of face recognition based on transductive learning classifier. Transductive learning classifier is based on SVM, it used the user feedback information to mark a few face images beforehand, then it adopted the transductive learning classifier to identify and mark the massive unknown face images. Experimental result shows that the proposed face recognition algorithm is effective, false acceptance rate and false rejection rate is lower than PCA and LDA. © 2010 IEEE.


He J.-F.,Harbin Institute of Technology | Li B.-P.,Chinanorth Optical Electrical Technology Co. | Tong Z.-Z.,Harbin Institute of Technology | Yang H.-B.,Chinanorth Optical Electrical Technology Co. | Han J.-W.,Harbin Institute of Technology
Zhendong yu Chongji/Journal of Vibration and Shock | Year: 2011

A shaking table is an important facility for earthquake damage testing of large scale structures like high buildings, large bridges and infrastructural systems. To improve the payload capacity in the test for large-scale structures or real-scale structures, hydraulically redundant actuated parallel mechanisms are usually adopted. By exploring the interactions between the mechanical parts and the hydraulially actuated systems, an integrated model of hydraulically redundant actuated shaking table was provided. Then, a framework of degree-of-freedom (DoF) control for this type of shaking table was put forward. To regulate forces among the redundant actuated systems and to reduce force couplings, an inner force balancing control method based on pseudo-inverse of Jacobian matrix was also employed. Simulations validated the proposed DoF control and inner force balancing method.

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