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FPGA implementation of a real-time pedestrian detection processor aided by E-HOG IP

Journal of Computers (Taiwan) 2017年第2期28卷 87-103页

作者： Guo, Ai-Ying Xu, Mei-Hua Ran, Feng Li, Ang School of Mechatronics Engineering and Automation Shanghai University Shanghai China Department of Electrical and Mechanical Engineering Shan Xi Light Industry and Technical College Taiyuan China Microelectronics Research and Development Center Shanghai University Shanghai China

This paper describes a real-time pedestrian detection processor of Field Programmable Gate Arrays (FPGA) using a novel structure aided by E-HOG IP. This structure proposes a three stages detection to reduce the amount of calculation and improve the processing speed. Compared to the traditional methods, in the first stage, the Sobel-step can select windows of interest before feature extraction and classification. In the second stage, the uniform-LBP (Local Binary Pattern), which is implemented cell by cell, has approximately half-dimension of HOG and simultaneous SVM (Support Vector Machine) to decrease total computation. In the third stage, improved HOG (Histogram of Oriented Gradient), called E-HOG (Efficient-HOG), is suitable to be realized in hardware. E-HOG and SVM are adopted to improve the detection rate. To evaluate the performance, the proposed structure is implemented into an FPGA while the E-HOG is manufactured as one common IP. The results indicate that this processor can detect pedestrians with 48 fps for VGA resolution under 25Mhz in low FPGA series and satisfy the demand of real-time.

关键词： Support vector machines

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Vibration signal model for fault diagnosis of sun gear in epicyclical gearboxes

Vibration signal model for fault diagnosis of sun gear in ep...

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作者： Zhang, Lun Hu, Niaoqing Hu, Lei Gu, Fengshou Laboratory of Science and Technology on Integrated Logistics Support National University of Defense Technology Changsha Hunan410073 China College of Mechatronics and Automation National University of Defense Technology Changsha Hunan410073 China Centre for Efficiency and Performance Engineering University of Huddersfield Queensgate HuddersfieldHD1 3DH United Kingdom

Signal models of machinery components are helpful to understand influence and character of various fault modes without conducting costly and timeconsuming experiments;it also brings convenience to validate new fault diagnosis methods for scientist and engineers. Researchers have built models such as lumped parameter model and finite element model to study problem of interest. However, these models are time-consuming to simulate faults in epicyclical gearbox, some of them could not implant fault on specified gear tooth. In this paper, a simplified fault implantable signal model is established considering meshing regularity between given sun gear tooth and planet gear, as well as amplitude modulation effect caused by rotating of carrier. Theoretical derivations are validated through spectrum analysis of simulation signal, moreover, experimental data collected from fault-seeded and baseline experiments are analyzed to validate the model, computing time of new model and lumped parameter model are compared to show computational efficiency of the model. According to signal analysis and computing time comparison, the signal model proposed in this paper is effective and efficient. © 2018 COMADEM International. All Rights Reserved.

关键词： Failure analysis

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A new metallic coriolis vibratory gyroscope (CVG) with multiple-shell structure 10

A new metallic coriolis vibratory gyroscope (CVG) with multi...

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10th DGON Inertial Sensors and Systems, ISS 2016

作者： Xi, X. Wu, Y.L. Xiao, D.B. Zhang, Y.M. Wu, X.Z. College of Mechatronics Engineering and Automation National University of Defense Technology Yanwachi Street 47 Changsha410073 China

ISBN: (纸本)9781509025152

A type of new metallic coriolis vibratory gyroscope (CVG) with multiple-shell structure is presented. Based on principle of structural topology evolution, a 30 mm diameter resonator comprising a bottom plate, a cylindrical support and 3 resonant shells is designed. The proposed multiple-shell structure increases the effective vibrating mass of the resonator and simultaneously avoids Q factor decrease compared with the single-thick-shell design. The design methodology, manufacture process and circuit strategy of the new CVG is discussed in the paper. The tested Q factor of the metallic resonator is about 10,000 in the atmospheric environment, and the gyroscope prototype without vacuum package presents a bias instability of about 18.5/°h under room temperature. © 2016 IEEE.

关键词： Shells (structures)

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Design and Performance Analysis of a New Environmental Energy Powered Marine Vehicle

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IOP Conference Series: Materials Science and engineering 2018年第5期394卷

作者： Chongfei Sun Jianzhong Shang Zirong Luo Zhongyue Lu Yiming Zhu Guoheng Wu College of Mechatronics and Automation National University of Defense Technology Changsha 410073 China School of Mechanical Aerospace and Civil Engineering University of Manchester Manchester M17JR UK

The efficient and reliable marine vehicle is an important tool to develop marine resources, and the lack of reliable power supply methods is one of the important issues that restrict the development of marine vehicle. This paper designs a new type of marine vehicle that can use environmental energy to absorb wave energy and convert it into electricity. The generated electric energy is temporarily stored in a battery or directly supplied to its own equipment. This article describes the main structure of the new marine vehicle and focuses on the energy module of the vehicle. And the energy module has been analysed and optimized. In this paper, the influence of the blade angle on the performance characteristics of the energy module is numerically analysed, and its variation law which lays a foundation for further structural optimization is obtained.

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Analysis of Wave Energy and Energy Storage Characteristics of Wave Energy Converters

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IOP Conference Series: Materials Science and engineering 2018年第4期394卷

作者： Chongfei Sun Zirong Luo Jianzhong Shang Zhongyue Lu Yiming Zhu Guoheng Wu College of Mechatronics and Automation National University of Defense Technology Changsha 410073 China School of Mechanical Aerospace and Civil Engineering University of Manchester Manchester M17JR UK

With the development of wave energy extraction technology, the performance requirements of wave energy converters have also become higher in order to maximize operating efficiency and the use of wave energy. In this paper, the wave energy characteristics and energy storage characteristics of current common wave energy converters are studied for this demand. Because small-scale wave energy convertors are characterized by their strong mobility and relatively lower power generation, it is not easy to integrate the generated energy directly into the power grid. Therefore, a small, highly efficient and environmentally friendly storage method is needed. Through investigation, the lithium battery pack is used to store the energy output from the convertors by means of a filtered regulated charging circuit.

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Adaptive higher order sliding mode attitude control for hypersonic glide vehicles 35

Adaptive higher order sliding mode attitude control for hype...

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35th Chinese Control Conference, CCC 2016

作者： Weijie, Kong Hao, Yuan Peng, Li Zhiqiang, Zheng College of Mechatronics Engineering and Automation National University of Defense Technology Changsha410073 China College of Aerospace and Materials Engineering National University of Defense Technology Changsha410073 China

ISBN: (纸本)9789881563910

In this paper, a robust adaptive higher order sliding mode attitude control scheme is proposed for near space hypersonic glide vehicles. This problem can be viewed as the finite time stabilization of a higher order input-output dynamic system with bounded uncertainties. The control scheme developed is based on geometric homogeneity and dual layer adaptive sliding mode control. Simulation results show the effectiveness of the proposed controller to track the guidance instruction for the 6-DOF model of hypersonic reentry vehicles. © 2016 TCCT.

关键词： dual layer adaptation high order sliding mode hypersonic glide vehicles Near space

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Understanding coupled factors that affect the modelling accuracy of typical planar compliant mechanisms

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Frontiers of Mechanical engineering 2016年第2期11卷 129-134页

作者： Guangbo HAO Haiyang LI Suzen KEMALCAN Guimin CHEN Jingjun YU School of Engineering University College Cork Cork T12 YN60Ireland School of Engineering University College Cork Cork T12 YN60Ireland Department of Mechanical Engineering Trakya UniversityEdirne Turkey School of Mechatronics Xidian University Xi'an 710071 China School of Mechanical Engineering and Automation Beihang UniversityBeijing 100191 China

In order to accurately model compliant mechanism utilizing plate flexures, qualitative planar stress （Young＇s modulus） and planar strain （plate modulus） assumptions are not feasible. This paper investigates a quantitative equivalent modulus using nonlinear finite element analysis （FEA） to reflect coupled factors in affecting the modelling accuracy of two typical distrib- uted-compliance mechanisms. It has been shown that all parameters have influences on the equivalent modulus with different degrees; that the presence of large load-stiffening effect makes the equivalent modulus significantly deviate from the planar assumptions in two ideal scenarios; and that a plate modulus assumption is more reasonable for a very large out-of-plane thickness if the beam length is large.

关键词： coupling factors modelling accuracy com-pliant mechanisms equivalent modulus

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Investigation of flow characteristics in helical separator

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IOP Conference Series: Materials Science and engineering 2018年第4期452卷

作者： Chuangchuang Zhou Hua Guo Xiaohu Sang Xiaojun Zhou School of Mechatronics Engineering and Automation Shanghai University Shanghai 20007 China. Shanghai Technical Institute of Electronics & Information Shanghai 201411 China. College of Information & Mechanical and Electrical Engineering Ningde Normal University Ningde 352100 China.

The oil recovery technology of submersible electric pump has the advantages of multi-function and strong adaptability, which has become one of the important lifting methods at present. High gas-liquid ratio and low downhole pressure in oil well will lead to a large amount of natural gas in crude oil. Cavitation and air lock will shorten the pump operation cycle. Therefore, a gas separator is installed at the inlet of the pump to separate the gas from the well fluid, reducing the volume fraction of the gas entering the pump and improving the production efficiency of the pump. In this study, the flow passage of the helical separator is treated as an equal-section pipeline in the research process. Through theoretical analysis and numerical simulation, the separation efficiency and pressure loss in the helical separator are studied and the expression of the total liquid phase drag multiplier applicable to the separator structure is obtained by the method of fitting.

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Combustion simulation and key parameter optimization for opposite axial piston engine in small-scale

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Journal of Central South University 2015年第9期22卷 3397-3408页

作者：张雷徐海军潘存云徐小军 College of Mechatronics Engineering and Automation National University of Defense Technology

As potential alternative power sources used in portable electric generators, opposite axial piston engines in small-scale were investigated to show their advantages in power density. A novel cylinder charge system was introduced, based on which a quasi-dimension model and a CFD(computational fluid dynamics) model were established. Comparison of those two models was carried out to validate the quasi-dimension model. Furthermore, optimal diameter of charge cylinder and speed were determined after evaluating the quasi-dimension model based on different parameters. High agreement between the quasi-dimension model and the CFD model validates the quasi-dimension model. Further studies show that the power of engine increases with the diameter of charge cylinder. However, a too big charge cylinder lowers the fuel efficiency instead. Taking economic influence into consideration the charge cylinder should be 1.4 times power cylinder, which could ensure the power density, volumetric efficiency and fuel economic at the same time. Axial piston engine running at 1.0×104 r/min could achieve a better overall performance. The maximal power of engine with optimal parameters is 0.82 k W, which fits the power need of the portable electric generators completely.

关键词： opposite axial piston engine quasi-dimension model computational fluid dynamics（CFD） optimal design

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Modeling and simulation of CMS04 maglev train with active controller

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Journal of Central South University 2015年第4期22卷 1366-1377页

作者：李金辉周丹峰李杰张耿余佩倡 College of Mechatronics Engineering and Automation National University of Defense Technology

The application of new-designed levitation controller requires extensive validation prior to enter into commercial service. However, huge mounts of approximations and assumptions lead the theoretical analysis away from the engineering practice. The experimental methods are time-consuming and financial expensive, even unrealizable due to the lack of suitable sensors. Numerical simulations can bridge the gap between the theoretical analysis and experimental techniques. A complete overall dynamic model of maglev levitation system is derived in this work, which includes the simple-supported bridges, the calculation of electromagnetic force with more details, the stress of levitation modules and the cabin. Based on the aforementioned model, it shows that the inherent nonlinearity, inner coupling, misalignments between the sensors and actuators, and self-excited vibration are the main issues that should be considered during the design process of controller. Then, the backstepping controller based on the mathematical model of the module with reasonable simplifications is proposed, and the stability proofs are listed. To show the advantage of controller, two numerical simulation experiments are carried out. Finally, the results illustrating closed-loop performance are provided.

关键词： maglev modeling simulation levitation backstepping

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