中国开放科研知识云: 检索

Modeling and analysis of machining force in elliptical vibration cutting 会议论文
4th International Conference on Manufacturing Science and Engineering, ICMSE 2013, March 30, 2013 - March 31, 2013, Dalian, China
Lin J. Q.; Liu J. H.; Gao X. P.; Wang S. Q.

收藏 | 浏览/下载：28/0 | 提交时间：2014/05/15

Precision analysis of simulation systems with hardware-in-loop caused by performance of three-Axis virtual flight motion simulator (EI CONFERENCE) 会议论文
2011 International Conference on Manufacturing Science and Technology, ICMST 2011, September 16, 2011 - September 18, 2011, Singapore, Singapore
Wang T.; Zhu M.-C.; Yin S.-L.; Jia H.-G.

收藏 | 浏览/下载：33/0 | 提交时间：2013/03/25

Simulation systems with hardware-in-loop are composed by three-Axis virtual flight motion simulator simulation computer load torque simulator and visual simulation systems. Three-Axis Virtual Flight Motion Simulator are used to simulate the attitude of missile in simulation system with hardware-in-loop so its performance influenced the result of simulation directly. This paper mainly analyzed the factors which influenced the performance of a three-Axis virtual flight motion simulator which we are used now in the lab then analyzed the entire simulation system's error caused by these factors through numerical simulation method. By analysis we can see that bandwidth is the main factor influenced the precision of simulation systems with hardware-in-loop mechanical device installation error and measurement error may also cause some errors of the systems at the same time.

Design of motion adjusting system for space camera based on ultrasonic motor (EI CONFERENCE) 会议论文
International Symposium on Photoelectronic Detection and Imaging 2011: Space Exploration Technologies and Applications, May 24, 2011 - May 26, 2011, Beijing, China
Xu K.; Jin G.; Gu S.; Yan Y.; Sun Z.

收藏 | 浏览/下载：74/0 | 提交时间：2013/03/25

Drift angle is a transverse intersection angle of vector of image motion of the space camera. Adjusting the angle could reduce the influence on image quality. Ultrasonic motor (USM) is a new type of actuator using ultrasonic wave stimulated by piezoelectric ceramics. They have many advantages in comparison with conventional electromagnetic motors. In this paper some improvement was designed for control system of drift adjusting mechanism. Based on ultrasonic motor T-60 was designed the drift adjusting system which is composed of the drift adjusting mechanical frame the ultrasonic motor the driver of Ultrasonic Motor the photoelectric encoder and the drift adjusting controller. The TMS320F28335 DSP was adopted as the calculation and control processor photoelectric encoder was used as sensor of position closed loop system and the voltage driving circuit designed as generator of ultrasonic wave. It was built the mathematic model of drive circuit of the ultrasonic motor T-60 using matlab modules. In order to verify the validity of the drift adjusting system was introduced the source of the disturbance and made simulation analysis. It designed the control systems of motor drive for drift adjusting system with the improved PID control. The drift angle adjusting system has such advantages as the small space simple configuration high position control precision fine repeatability self locking property and low powers. It showed that the system could accomplish the mission of drift angle adjusting excellent. 2011 SPIE.

Design of motion compensation mechanism of satellite remote sensing camera (EI CONFERENCE) 会议论文
International Symposium on Photoelectronic Detection and Imaging 2011: Space Exploration Technologies and Applications, May 24, 2011 - May 26, 2011, Beijing, China
Gu S.; Yan Y.; Xu K.; Jin G.

收藏 | 浏览/下载：37/0 | 提交时间：2013/03/25

Geocentric distance's errors' correction of space cameras based on USGS DEM (EI CONFERENCE) 会议论文
2011 IEEE 3rd International Conference on Communication Software and Networks, ICCSN 2011, May 27, 2011 - May 29, 2011, Xi'an, China
Yan D.; Xu S.; Li W.

收藏 | 浏览/下载：14/0 | 提交时间：2013/03/25

In order to correct the geocentric distance's error of TDI (Time Delay and Integration) CCD space camera in calculation of image motion compensation the data source of the earth's height above sea level USGS DEM (United States Geological Survey Digital Elevation Model) has been introduced to make digital elevation map the match error of the forward direction (the integral direction of TDI CCD) has been greatly decreased by correcting the geocentric distance error and eliminate the influence to the relative error of image motion velocity and correct the error generated by the different heights above sea level. After correcting which greatly improves the imaging quality of TDI CCD space camera. 2011 IEEE. a model of image motion calculation of nadir has been introduced the calculation and analysis of the model shows that: the maximum error of image motion velocity about 1.72% has been decreased to 0.06% and the influence of the geocentric distance error to the relative error of image motion velocity has been analyzed with the model

The new approach for infrared target tracking based on the particle filter algorithm (EI CONFERENCE) 会议论文
International Symposium on Photoelectronic Detection and Imaging 2011: Advances in Infrared Imaging and Applications, May 24, 2011 - May 24, 2011, Beijing, China
Sun H.; Han H.-X.

收藏 | 浏览/下载：50/0 | 提交时间：2013/03/25

Target tracking on the complex background in the infrared image sequence is hot research field. It provides the important basis in some fields such as video monitoring precision and video compression human-computer interaction. As a typical algorithms in the target tracking framework based on filtering and data connection the particle filter with non-parameter estimation characteristic have ability to deal with nonlinear and non-Gaussian problems so it were widely used. There are various forms of density in the particle filter algorithm to make it valid when target occlusion occurred or recover tracking back from failure in track procedure but in order to capture the change of the state space it need a certain amount of particles to ensure samples is enough and this number will increase in accompany with dimension and increase exponentially this led to the increased amount of calculation is presented. In this paper particle filter algorithm and the Mean shift will be combined. Aiming at deficiencies of the classic mean shift Tracking algorithm easily trapped into local minima and Unable to get global optimal under the complex background. From these two perspectives that "adaptive multiple information fusion" and "with particle filter framework combining" we expand the classic Mean Shift tracking framework.Based on the previous perspective we proposed an improved Mean Shift infrared target tracking algorithm based on multiple information fusion. In the analysis of the infrared characteristics of target basis Algorithm firstly extracted target gray and edge character and Proposed to guide the above two characteristics by the moving of the target information thus we can get new sports guide grayscale characteristics and motion guide border feature. Then proposes a new adaptive fusion mechanism used these two new information adaptive to integrate into the Mean Shift tracking framework. Finally we designed a kind of automatic target model updating strategy to further improve tracking performance. Experimental results show that this algorithm can compensate shortcoming of the particle filter has too much computation and can effectively overcome the fault that mean shift is easy to fall into local extreme value instead of global maximum value.Last because of the gray and fusion target motion information this approach also inhibit interference from the background ultimately improve the stability and the real-time of the target track. 2011 Copyright Society of Photo-Optical Instrumentation Engineers (SPIE).

Design and analysis of auto-focus assembly for spaceborne remote sensing camera (EI CONFERENCE) 会议论文
2011 International Conference on Electronics, Communications and Control, ICECC 2011, September 9, 2011 - September 11, 2011, Ningbo, China
Chen W.; Ding Y.; Hui S.; Gao X.

收藏 | 浏览/下载：20/0 | 提交时间：2013/03/25

Spaceborne remote sensing camera may be out of focus when the environment and photographic distance changes. In order to get higher ground sampled distance for the camera based on the experience gained from the development of a remote sensing camera working principle of auto-focus assembly control system was discussed. Time of waveform extraction was reduced. It sets force an auto-focus assembly that uses cam and line guide rail in order to move the lens group. The motion error of the auto-focus assembly was difficult to be eliminated and would affect on the focusing accuracy of the spaceborne remote sensing camera directly. So it was analyzed at both ends of the focusing structure. The CCD detector can keep stable when the remote sensing camera is imaging. The motion error was tested to verify the validity of the simulation result and it is less than 0.01mm. Its accuracy meets using demand. The focusing method of moving focal plane is suitable for spaceborne remote sensing camera. 2011 IEEE.

Approach for detecting crowd panic behavior based on fluid kinematic features and entropy (EI CONFERENCE) 会议论文
International Workshop on Advanced Computational Intelligence and Intelligent Informatics, IWACIII 2011, November 19, 2011 - November 23, 2011, Suzhou, China
Cao S.; Zhang X.; Cao W.; Liu C.; Li Y.; Li P. C.

收藏 | 浏览/下载：21/0 | 提交时间：2013/03/25

Crowd panic behavior detection is an important task in video analysis and event recognition whose purpose is to detect when the panic behavior happened and alarming the abnormal event timely. In this paper the crowd is regard as a fluid and the crowd motion is described by four fluid kinematic features (divergence vorticity gradient tensor invariant and rotation tensor invariant). To discriminate the panic event from normal crowd behavior an information entropy is calculated as a high level feature based on the fluid kinematic features. Experimental results show that the entropy raised dramatically once a panic event happened.

Image motion compensation for a certain aviation camera based on Lucy-Richardson algorithm (EI CONFERENCE) 会议论文
2011 International Conference on Electronics and Optoelectronics, ICEOE 2011, July 29, 2011 - July 31, 2011, Dalian, China
Zhong C.; Fu J.; Ding Y.

收藏 | 浏览/下载：15/0 | 提交时间：2013/03/25

According to the actual situation when high quality and high precision are required for the image both beforehand and afterwards compensation should be used. In this paper we use Lucy-Richardson algorithm to compensate image motion of a certain aviation camera as an afterwards compensation. Firstly we analyze the imaging principle of the camera and the reasons that cause image motion. Then we have a brief introduce of the Lucy-Richardson algorithm. At last in order to show the feasibility of the method we do some simulation. Through theoretical and practical analysis experiments and test we conclude the Lucy-Richardson algorithm can be used to compensate image motion for the certain camera. 2011 IEEE.

United steering of control moment gyros for small satellite with limited gimbal rate (EI CONFERENCE) 会议论文
2010 IEEE International Conference on Information and Automation, ICIA 2010, June 20, 2010 - June 23, 2010, Harbin, Heilongjiang, China
Xu K.; Jin G.; Chen C.

收藏 | 浏览/下载：16/0 | 提交时间：2013/03/25

Single Gimbal Control Moment Gyroscopes (SGCMG) can could provide large control torque and quick attitude maneuver rate to small satellites without any increase in power volume and mass which will help small satellites become more powerful. Singularity avoidance and failure steering are two important problems to SGCMGs and also the main focus in this field. A new united steering law for SGCMGs with capabilities of singularity avoidance and quick transition of singularity surfaces is developed in this paper. To ensuring the existence of null motion the commanded output of controller was changed real-timely as the variation of singularity measurement of SGCMGs which can avoid the gimbal angle rate saturation. This developed steering law could help the SGCMGs provide real-time control toques in spite of limitation of gimbal angle rate. Simulation analysis is conducted for a certain 4-SGCMG system mounted on a small satellite. Simulation results indicate that the steering law is very effective in singularity avoidance. 2010 IEEE.

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