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Zhao P.,Beihang University | Liu Z.,Beihang University | Cheng W.,Chinese Helicopter Research and Development Institute
Advances in Intelligent and Soft Computing | Year: 2012

Mean-shift based tracking technique is successfully used in target tracking. However, classic Mean-shift based tracking algorithm uses fixed kernel-bandwidth, which limits the performance when the target's orientation and scale change. In this article, we firstly outlines the basic concepts of Mean Shift Algorithm, and Mean Shift algorithm for target tracking in the visual tracking and its application in visual tracking. Then an improved adaptive kernel-based object tracking is proposed, which extends 2-dimentional mean shift to 4-dimentional, meanwhile combine s multiple scale and orientation theory into tracking algorithm. A multi-kernel method is also brought forward to improve the tracking Accuracy. Finally, experimental results validate that the new algorithm can adapt to the changes of orientation and scale of the target effectively. © 2012 Springer-Verlag GmbH Berlin Heidelberg.

Ren Y.,Beihang University | Ren Y.,Inner Mongolia University of Science and Technology | Liu Z.,Beihang University | Cheng W.,Chinese Helicopter Research and Development Institute | Zhou R.,Beihang University
Advances in Intelligent and Soft Computing | Year: 2012

Friction torque is the main factor that influences dynamic response performance of high precise servo systems. To compensate for the friction torque, a compound control strategy based on backstepping and acceleration feedback with friction observer is proposed. In this control strategy, the backstepping controller with integral element was used for the position loop; the acceleration feedback controller with friction observer was introduced to compensate for friction torque. The simulation results show that dynamic friction torque is inhibited more effectively, and the robustness of system for the exterior disturbance is also improved simultaneously. © 2012 Springer-Verlag GmbH Berlin Heidelberg.

Chen Y.,Nanjing University of Aeronautics and Astronautics | Chen Y.,Chinese Helicopter Research and Development Institute | Gao L.,Huazhong University of Science and Technology | Wang C.,Commercial Aircraft Corporation of China | And 2 more authors.
Zhongguo Jixie Gongcheng/China Mechanical Engineering | Year: 2010

In order to improve helicopter collaborative design, a method of regionalization design in context for DMU was proposed and the system frame for implementation of the method was designed. Based on the characteristics of helicopter development, the expression model of DMU regionalization based on hierarchical tree of axis aligned bounding box (AABB) was proposed to search the DMU region; the relationship graphic of model link (RGML) was proposed to express the relationship of model link (RML) in DMU, and the impacts of correlative models in context can be analyzed effectively. The method was used to develop some helicopters, the accuracy rate of models search and the efficiency of models loading from whole helicopter DMU are improved, and the cycle of sub-system optimization and part change is shortened.

Zhang M.,Beihang University | Meng Q.,Beihang University | Hu W.,Beihang University | Shi S.,Chinese Helicopter Research and Development Institute | And 2 more authors.
International Journal of Fatigue | Year: 2010

According to the law of thermodynamics, a new damage evolution equation is advanced in the present study to predict the fatigue life of the Pitch-Change-Link component. As its premise, the fatigue life prediction method for smooth specimens under the repeated loading with constant strain amplitude is constructed. In addition, based on the theory of conservative integral, the closed form relation for notched specimens between the maximum stress and fatigue life is derived, by reference to which the material parameters in damage evolution equation are obtained with fatigue experiment data of standard specimens. The damage mechanics-finite element method operates with APDL language code on the ANSYS platform. Finally, the mean fatigue crack initiation life of Pitch-Change-Link is predicted with the newly proposed method, that is damage mechanics-finite element method. What's most important, the calculated results comply with the experimental data. © 2010 Elsevier Ltd. All rights reserved.

Huang X.,Jiujiang Vocational and Technical College | Wang W.,Chinese Helicopter Research and Development Institute | Jiang W.,Chinese Helicopter Research and Development Institute
Jixie Qiangdu/Journal of Mechanical Strength | Year: 2012

Rotor system is the core component of the helicopter, flexible blade with the spherical thrust bearing connected to provide the wielding, shimmy and pitch degrees of freedom, the stiffness characteristics is one of the main mechanical properties. Test the spherical thrust bearing compression, torsion and bending stiffness characteristics by twisting the screw to drive the semi-circular fixture. These results indicated that the test method is distinctive and general. It can accurately determine whether the spherical thrust bearing is qualified and provide a test before installing for different type of spherical thrust bearings.

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