-
Record 169 of
Title:High-speed data acquisition and processing system for multi-spectral imagery system
Author(s):Wang, Cailing(1); Liu, Xuebin(2); Chen, Xiaolai(2); Hu, Bingliang(2); Li, Yun(2)
Source: 2010 Symposium on Photonics and Optoelectronic, SOPO 2010 - Proceedings Volume: Issue: DOI: 10.1109/SOPO.2010.5504471 Published: 2010
Abstract:This paper describes a high-speed data acquisition and processing system which has been successfully operated on the multi-spectral imagery system. The system, which is based on PCI-E interface, can collect data as 280MBps and store over 60 minutes per times without losing frames. This study discusses several main problems during hardware design and software design. ?2010 IEEE.
Accession Number: 20103013104363
-
Record 170 of
Title:Gaussian Sum Particle Filter for spacecraft attitude estimation
Author(s):Yang, Shaodong(1); Wen, Desheng(1); Sun, Jing(1); Ma, Junyong(1)
Source: ICSPS 2010 - Proceedings of the 2010 2nd International Conference on Signal Processing Systems Volume: 3 Issue: DOI: 10.1109/ICSPS.2010.5555680 Published: 2010
Abstract:A novel and efficient spacecraft attitude estimation method using Gaussian Sum Particle Filter is proposed based on vector observations. The attitude is represented by quaternion, and the local error is represented by the modified Rodrigues parameters. Gaussian mixture model is used to approximate the posterior density of the state, and the state update is carried out by sampling based methods. Meanwhile Expectation Maximization algorithm is introduced to avoid the collapsing of Gaussian mixture terms. The efficiency of Gaussian sum particle filter estimator for spacecraft attitude is validated by numerical simulation. The simulation results show that Gaussian mixture particle filter is superior to Particle Filter and Unscented Kalman Filter for spacecraft attitude estimation. ? 2010 IEEE.
Accession Number: 20104013270873
-
Record 171 of
Title:Fuzzy adaptive control of free-floating space robot based on dead-zone compensator
Author(s):Liu, Shuang(1); Ma, Caiwen(1); Xing, Wei(1); Luo, Cuihua(1)
Source: Proceedings - 2010 International Symposium on Computational Intelligence and Design, ISCID 2010 Volume: 2 Issue: DOI: 10.1109/ISCID.2010.100 Published: 2010
Abstract:This paper proposes a fuzzy adaptive controller based on dead-zone compensator for a free-floating space robot (FFSR) in the presence of the unmodeled nonlinear dynamics and additional disturbances. In the micro-gravity space environment, the FFSR lacks a fixed base. As a result, there is high dynamic coupling between the manipulators and the free-floating base, which leads to two inherent difficulties, which are non-linear parameterization of the dynamic equation and both kinematic and dynamic parameter uncertainties. These uncertainties make the dynamic equation of FFSR more complicated than that of the fix-based comparisons. And the control method for fixbased robot can not be applied directly for the FFSR system. In order to overcome these obstacles, we use the dead-zone compensator including a fuzzy control system to approximate the nonlinear dynamic function. The proposed controller could not only overcome the uncertainty but also efficiently track the desired trajectory of the manipulator joints in a finite time. The stability of the whole system is analyzed and then the structure of the controller is given. Through numerical simulations, the validity of the proposed scheme is also demonstrated. ? 2010 IEEE.
Accession Number: 20110813677344
-
Record 172 of
Title:Robust adaptive control of free-floating space robot based on fuzzy compensation
Author(s):Liu, Shuang(1); Ma, Caiwen(1); Luo, Cuihua(1); Wang, Xiaobai(1)
Source: Proceedings - 2010 7th International Conference on Fuzzy Systems and Knowledge Discovery, FSKD 2010 Volume: 2 Issue: DOI: 10.1109/FSKD.2010.5569382 Published: 2010
Abstract:This paper proposes an adaptive controller for a free-floating space robot (FFSR) in the presence of kinematic and dynamic model uncertainties. Because of high dynamical coupling between the actively operated manipulator and the free-floating base, two inherent difficulties exist, such as non-linear parameterization of the dynamic equation and both kinematic and dynamic parameter uncertainties. In order to compensate these uncertainties, we use the fuzzy logic system (FLS) that has the capability to approximate any nonlinear function. The proposed adaptive controller does not involve complex calculations, but it is still possible for the system to generate a suitable input torque and a compensator to overcome the uncertainties. Then, the stability is proved and the structure of the control method is given. To verify the validity of the proposed method, a computer simulation of a two-link planar FFSR is carried out. ?2010 IEEE.
Accession Number: 20104813422498
-
Record 173 of
Title:Adaptive control of free-floating space robot with disturbance based on robust fuzzy compensator
Author(s):Liu, Shuang(1); Ma, Caiwen(1); Luo, Cuihua(1); Wang, Xiaobai(1)
Source: Proceedings - 2010 2nd International Conference on Intelligent Human-Machine Systems and Cybernetics, IHMSC 2010 Volume: 1 Issue: DOI: 10.1109/IHMSC.2010.13 Published: 2010
Abstract:This paper proposes an adaptive controller for a free-floating space robot (FFSR) in the presence of friction, disturbance and variation of payload based on robust fuzzy compensator. In the micro-gravity environment, the FFSR lacks a fixed base, so the high dynamic coupling between the manipulators and the free-floating base leads to two inherent difficulties, such as non-linear parameterization of the dynamic equation and both kinematic and dynamic parameter uncertainties. In order to overcome these obstacles, we use the fuzzy logic system (FLS) to approximate the nonlinear dynamic function. The proposed controller does not involve any complex calculations, but it is still possible to overcome the uncertainty and efficiently track the desired trajectory of the manipulators in a short time. The stability of the controller is demonstrated, and meanwhile, the structure of the controller is given. Through numerical simulations, the validity of the proposed scheme is also demonstrated. ? 2010 IEEE.
Accession Number: 20104713407161
-
Record 174 of
Title:The design and control of fine tracking loop of ATP system for free space laser communication
Author(s):Xing, Wei(1); Liang, Yanbing(1); Liu, Shuang(1)
Source: 2nd International Conference on Information Engineering and Computer Science - Proceedings, ICIECS 2010 Volume: Issue: DOI: 10.1109/ICIECS.2010.5677752 Published: 2010
Abstract:High accuracy of laser-beam pointing is crucial for reliable operation of Free Space Laser Communication. The tracking accuracy and bandwidth of rejection frequency response are directly determined by the performance of the fine tracking loop of Acquisition, Tracking and Pointing (ATP) system. In this paper, the architecture of the fine tracking system for the designing optical communication terminal is described. And each component's unique function, hardware choice and operating principle will be discussed. Furthermore, in order to track with the beacon real time and high precisely, a novel control algorithm is presented in this paper - dynamic matrix control (DMC), which performs well in tracking system and compared with traditional PID control it has many advantages such as better Robust, less demanding on the system model and better control effect. ?2010 IEEE.
Accession Number: 20110813673605
-
Record 175 of
Title:Scale transformation for detecting weak periodic signal of stochastic resonance
Author(s):Wang, Guo-Fu(1,2); Zhang, Hai-Ru(1); Zhang, Fa-Quan(1); Ye, Jin-Cai(1); Wei, Li(1)
Source: Proceedings - 2010 International Conference on Intelligent Computing and Integrated Systems, ICISS2010 Volume: Issue: DOI: 10.1109/ICISS.2010.5656058 Published: 2010
Abstract:Aiming at the issue of the traditional stochastic resonance only applicable to deal with low-frequency signals, a high-frequency weak signal detection method based on scale transformation is proposed in this paper. The high-frequency weak signal mixed with noise is scaled to a low frequency signal. The signal conforms to the adiabatic elimination theory. So when it acts on stochastic resonance systems, the stochastic resonance can arise. The original high frequency weak signal mixed with noise can be retrieved by scaled up by the same ratio. To deal with the unknown frequency mixed with noise, the high frequency mixed signal is scaled down continuously to achieve a suitable matching parameters for the stochastic system. According to the change of resonance spectral peak value, the unknown frequency can be found from the mixed signal. This method is effective for future application. ? 2010 IEEE.
Accession Number: 20110313596136
-
Record 176 of
Title:Multi-target detection based on Hough transform and mean shift multi-scale clustering
Author(s):Li, Zhe(1,2); Su, Xiuqin(1)
Source: Proceedings - 2010 3rd International Congress on Image and Signal Processing, CISP 2010 Volume: 2 Issue: DOI: 10.1109/CISP.2010.5646940 Published: 2010
Abstract:Detection based on Hough Transform is a good way frequently employed to detect straight-line targets, but it bears problems as difficulty in selecting an appropriate threshold coefficient and target misjudgment. To solve those technical problems mentioned above, this paper proposes a novel algorithm based on Hough Transform and Mean Shift Multi-Scale Clustering (MSMSCHT). Firstly, the outline of targets is extracted and a primary selection is conducted by taking a low threshold. Then, the primary targets are treated with Multi-Scale Clustering, and the class centers can be obtained via Mean Shift algorithm. Finally, the target number and attitude parameters can be calculated adaptively by optimization of scales. For multi-target shaped in straight lines in sky background, this algorithm proposed can avoid the difficulty in the choice of an appropriate threshold by taking clustering method, thus can successfully complete detecting mission. Experimental results verify the efficacy of the proposed algorithm. ?2010 IEEE.
Accession Number: 20105213529875
-
Record 177 of
Title:Modelling and simulation of a two-axis tracking system
Author(s):Zhao, Z.M.(1); Yuan, X.Y.(1); Guo, Y.(1); Xu, F.(2); Li, Z.G.(3)
Source: Proceedings of the Institution of Mechanical Engineers. Part I: Journal of Systems and Control Engineering Volume: 224 Issue: 2 DOI: 10.1243/09596518JSCE830 Published: March 1, 2010
Abstract:In this paper, the modelling and simulation of a two-axis tracking system are introduced. First, dynamic modelling of a two-axis tracking system that is based on the Lagrange-Maxwell dynamic equation is presented. According to the established dynamic equation the coupling of system velocity and the inertia characteristics between the two axes are analysed. Then, the controller of the tracking system is designed using the inverse system method. Based on a certain type two-axis tracking system, the simulation is then made with MATLAB/Simulink, which includes position tracking and tracking error analysis. The simulation using Adams and Simulink is also presented. A comparison of the results from the two kinds of simulation indicates that the modelling of the two-axis tracking system is reasonable and the simulation results are rational. ? 2010 Author.
Accession Number: 20101612867663
-
Record 178 of
Title:A sub-pixel centroid algorithm for star image based on gaussian distribution
Author(s):Sun, Jing(1,2); L, Guangrui(1,3); Wen, Desheng(1); Xue, Bin(1); Yang, Shaodong(1,2)
Source: Transactions of the Japan Society for Aeronautical and Space Sciences Volume: 53 Issue: 182 DOI: 10.2322/tjsass.53.307 Published: 2010
Abstract:A novel centroid algorithm is proposed to acquire better centroid performance in a star image. Since photons incident on pixels of stars present a Gaussian point spread function (PSF), so, the centroid locations on the x and y-axis are calculated using the pixel intensity ratio and expand the Gaussian PSF to polynomials with respect to the centroid location. The angular separation error between star pairs is used to verify the proposed algorithm indirectly. The result clearly shows that the centroid accuracy achieves 1/33 of a pixel and is about two times better than the moment method, indicating the new algorithm is effective. ? 2011 The Japan Society for Aeronautical and Space Sciences.
Accession Number: 20113714314742
-
Record 179 of
Title:Testing & simulation of disturbance torque caused by cables in acquisition, tracking & pointing system
Author(s):Xu, Feng(1); Li, Zhi-Guo(2)
Source: 2010 IEEE International Conference on Mechatronics and Automation, ICMA 2010 Volume: Issue: DOI: 10.1109/ICMA.2010.5588754 Published: 2010
Abstract:In an acquisition, tracking & pointing system (ATPS), there are many cables as usual. The torque caused by cables (TC) is so powerful that it may influent on the control accuracy of the system. In this paper, a way of how to test TC was put forward. And the model of TC was made via the experiment results. It includes two parts. One is elastic force, the other is damp. Next, the influence on ATPS was simulated. The simulation results show that the influence of TC is very limit on closed loop system and is considerable on open loop system. So it should be thought much in the process of design. ? 2010 IEEE.
Accession Number: 20104813423707
-
Record 180 of
Title:The analyze of the interference hyper-spectral image features and compression
Author(s):Zhang, Lei(1,2,3); Zhang, Shancong(2); Bin, Xiangli(2); Quan, Shengxue(2)
Source: Proceedings of SPIE - The International Society for Optical Engineering Volume: 7658 Issue: DOI: 10.1117/12.867626 Published: 2010
Abstract:Interference hyper spectral image and the images contain some interference information which are collected by the LASIS are only middle results of the spectrometer, is a three-dimensional image. The amount of the data is large size, and need to be compressed. For testing the actual interference hyper spectral image, use different composed way, to compose of LAMIS and LADIS image, the LASIS image has different target with different spectral band, LAMIS has the same target with different spectrum, LADIS has the same spectrum with different target. The spatial correlation and spectral correlation are analyzed. The self-coefficient and cross-coefficient are also calculated. The method that LASIS extract into LADIS is proposed, which separate interference information form spatial image, and it is a new foundation for interference information protection of LASIS image. The feather of LASIS image is revealed, the results obtained can be use LASIS image processing and compressing. ? 2010 Copyright SPIE - The International Society for Optical Engineering.
Accession Number: 20105213525756
