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International Conference on Fluid Power and Mechatronics (FPM)

作者： Wanlu Jiang Yong Zhu Meng Wang Hebei Provincial Key Laboratory of Heavy Machinery Fluid Power Transmission and Control Yanshan University Qinhuangdao China Key Laboratory of Advanced Forging & Stamping Technology and Science (Yanshan University) Ministry of Education of China Qinhuangdao China

ISBN: (纸本)9781479987719

Aiming at the problem of extracting fault features from hydraulic pump under variable rotating speed, a fault diagnosis method based on order tracking was proposed. Firstly, the original signal was decomposed by ensemble empirical mode decomposition into a series of intrinsic mode function (IMF) components. Afterwards, the fault sensitive IMF was selected by combining energy spectrum and spectral kurtosis. Secondly, the selected IMF was processed by Hilbert demodulation and down-sampling. Moreover, an appropriate frequency band was chosen and the signal was further processed by wavelet cluster-based bandpass filtering. Then, the fault sensitive envelope signal was obtained. Thirdly, the instantaneous frequency was extracted from the envelop signal by wavelet ridge tracking, and the time instant of phase discrimination was further calculated. Moreover, the even angle spaced resample was performed to the envelope signal. Then, the time domain non-stationary signal was transformed to the angular domain stationary signal. Finally, the stationary signal was analyzed by order tracking, and the fault diagnosis was executed according to the order spectrum. Furthermore, an application was performed to the vibration signals of hydraulic pump under variable rotating speed. The signals were respectively acquired in four typical states, which were normal, loose slipper, slipper wear and swash plate wear. Results indicate that the proposed method can effectively extract the fault features of hydraulic pump and further realize fault diagnosis.

关键词： Vibrations Fault diagnosis Feature extraction Time-domain analysis Pumps Valves Demodulation

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Active Disturbance Rejection Trajectory Tracking Control for Two-Joint Driven by Pneumatic Artificial Muscles

Active Disturbance Rejection Trajectory Tracking Control for...

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2015 International Conference on Fluid Power and Mechatronics

作者： Ling Zhao Linlin Ge Yafei Yang Hebei Province Key Laboratory of Heavy Machinery Fluid Power Transmission and Control Yanshan University Key Laboratory of Advanced Forging & Stamping Technology and Science(Yanshan University) Ministry of Education of China School of Electrical Engineering Yanshan University

Active disturbance rejection control is proposed to study the problems on trajectory tracking and decoupling for a two-joint system driven by pneumatic artificial muscles. Because of coupling and nonlinearity, it is very hard to obtain good performance in trajectory tracking for the two-joint system. The active disturbance rejection nonlinear controller includes a tracking differentiator, an extended state observer and a nonlinear error feedback controller. The tracking differentiator is introduced to arrange a transitional process to track input signal and get differential signal. The extended state observer is designed to estimate the non-linearity of system. The nonlinear error feedback controller is designed to improve the performance of system. Simulation results are given to show the effectiveness of proposed controller in this paper.

关键词： Active disturbance rejection control two-joint system decoupling control pneumatic artificial muscle

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A precise frequency-domain integral method of vibration acceleration signal

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ICIC Express Letters 2015年第6期9卷 1617-1624页

作者： Zhu, Yong Jiang, Wanlu Hu, Haosong Kang, Hongzhi Hebei Provincial Key Laboratory of Heavy Machinery Fluid Power Transmission and Control Yanshan University No. 438 Hebei Street Qinhuangdao China Key Laboratory of Advanced Forging and Stamping Technology and Science Ministry of Education Yanshan University No. 438 Hebei Street Qinhuangdao China

Aiming at the defects of traditional frequency-domain integral (TFDI), a precise FDI (PFDI) based on vibration intensity (VI) and feature component extraction (FCE) was proposed. This method applied the merits of ensemble empirical mode decomposition (EEMD), and merged the superiorities of kurtosis, mean square error, energy and singular value decomposition (SVD) on feature extraction. The connotative feature components were extracted, and the desired signal was precisely reconstructed. Meanwhile, the optimal lower limit of cut-off frequency was determined according to the mutation feature of VI. Results indicate that the interference problem of invalid signal is commendably solved. Moreover, the low-frequency error is effectively overcome. © 2015 ICIC International.

关键词： Mean square error

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Incentives of nonlinear dynamics behaviors in electro-hydraulic servo system

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ICIC Express Letters 2015年第1期9卷 231-236页

作者： Zhu, Yong Jiang, Wanlu Liu, Siyuan Liu, Zhiqiang Hebei Provincial Key Laboratory of Heavy Machinery Fluid Power Transmission and Control Yanshan University No. 438 Hebei Street Qinhuangdao China Key Laboratory of Advanced Forging and Stamping Technology and Science Ministry of Education of China Yanshan University No. 438 Hebei Street Qinhuangdao China

Based on the nonlinear dynamics principle, the nonlinear dynamic model of electro-hydraulic servo system (EHSS) was established. The influence laws of nonlinear spring force and friction on dynamic characteristics of EHSS were explored. Moreover, the bifurcation characteristics arising from primary excitations were investigated. The incentives of nonlinear dynamics behaviors (NDBs) in EHSS were revealed. Results show that the dynamic differential equations of EHSS can be described by Duffing-Van Der Pol equation. When EHSS is in working, excitation force, spring force nonlinear term and damping can result in complicated NDBs. The results can provide theoretical guidance for the parameter optimization during EHSS designing.

关键词： Dynamics

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Solution of suspension cylinder subject to cosine distribution pressure and normal stress on both ends

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ICIC Express Letters 2015年第5期9卷 1513-1517页

作者： Zhao, Jingyi Zhang, Chunhui Liu, Wen Hebei Provincial Key Laboratory of Heavy Machinery Fluid Power Transmission and Control No. 438 Hebei Ave Qinhuangdao China Key Laboratory of Advanced Forging and Stamping Technology and Science No. 438 Hebei Ave Qinhuangdao China Colloge of Science Yanshan University No. 438 Hebei Ave Qinhuangdao China

In this paper, a stress function which meets both the biharmonic equations and boundary conditions are constructed in the three-dimensional space. Furthermore, the solution of a suspension cylinder subject to cosine distribution pressure on its inner and outer surfaces and normal stress on both ends are deduced. When strain values of cylinder are recorded by static strain tester on suspension cylinder, the experimental results are in accordance with the theoretic calculation. The analytic solution paves the way for the mathematic building and solution of cylinder with randomly uneven pressure. © 2015 ICIC International

关键词： Cylinders (shapes)

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Principle of Multi-roller Straightening Process and Quantitative Resolutions of Straightening Strategies

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Journal of Iron and Steel Research International 2014年第9期21卷 823-829页

作者： Jing YIN Jun ZHAO Shi-yan WANG Xian-song WAN Yue-lin LI College of Mechanical Engineering Ningbo University of Technology Key Laboratory of Advanced Forging and Stamping Technology and Science(Yanshan University) Ministry of Education of China CISDI R&D Co. Ltd.

The multi-roller straightening process of section steel is analyzed by the springback theory of small curva- ture plane bending. The theoretical analysis results prove the curvature unification in straightening process and clear- ly reveal the principle of the multi-roller straightening process. The principle can be described as~ the initial curva- tures are reduced by several times anti-bendingl meanwhile the initial curvature differences are diminished and the residual curvatures are unified~ finally, the member after curvature unification is straightened by the last anti-ben- ding. With the plastic region ratios becoming larger, the initial curvatures are more easily unified in straightening process. Based on the plastic region ratios and the required number of roller systems for unifying the initial curva- tures, the large deformation straightening strategy and the small deformation straightening strategy are redefined. The new definition provides an important theoretical basis for setting reliable reduction rules. Through the theoretical analysis results, a new straightener design philosophy is proposed to improve the straightening quality and further increase the adjustment precision as well as the flexibility of the last roller system. The adjustable end roller emerges as the times required, achieving a good effect in practical application.

关键词： section steel multi-roller straightening curvature unification plastic region ratio straightening strategy

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Solution of suspension cylinder subject to linear distribution pressure and different bending moment and shearing force on both ends

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ICIC Express Letters, Part B: Applications 2015年第6期6卷 1639-1644页

作者： Zhang, Chunhui Zhao, Jingyi Liu, Wen Hebei Provincial Key Laboratory of Heavy Machinery Fluid Power Transmission and Control Yanshan University No. 438 Hebei Ave Qinhuangdao China Key Laboratory of Advanced Forging and Stamping Technology and Science Yanshan University No. 438 Hebei Ave Qinhuangdao China Colloge of Science Yanshan University No. 438 Hebei Ave Qinhuangdao China

The suspension cylinder of a mining dump truck is usually stressed to deform and crack. In order to solve this problem so as to improve the service life and safety, the analytic solution meeting boundary conditions for internal surface of suspension cylinder subjected to linear distribution pressure and different bending moment and shearing force on both ends is deduced on the basis of structure of the cylinder and displacement functions. When strain values of cylinder are recorded by static strain tester on suspension cylinder, the experimental results are in accordance with the theoretic calculation. The study laid a foundation for the design and application of suspension cylinder. © 2015 ISSN.

关键词： Cylinders (shapes)

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Active Disturbance Rejection Trajectory Tracking Control for Pneumatic Servo System Based on Backstepping Approach

Active Disturbance Rejection Trajectory Tracking Control for...

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第三十四届中国控制会议

作者： Yafei Yang Ling Zhao Xiaozhao Fan Zhixin Liu School of Electrical Engineering Yanshan University Hebei Province Key Laboratory of Heavy Machinery Fluid Power Transmission and Control Yanshan University Key Laboratory of Advanced Forging & Stamping Technology and Science (Yanshan University) Ministry of Education of China College of Mechanical Engineering Yanshan University

ISBN: (纸本)9781467374439

This paper presents an improved active disturbance rejection controller to study the trajectory tracking problem of a pneumatic servo system. It is a challenging job to track a given trajectory for pneumatic system with strong nonlinearity. The designed active disturbance rejection controller consists of tracking differentiator, extended state observer and nonlinear *** differentiator is designed to arrange a transition process for the given signal and get its corresponding differential *** state observer has advantages in observing states and estimating the nonlinear part of system. Moreover, a nonlinear controller is derived on the basis of backstepping approach. Finally, simulation results indicate the capabilities of the proposed method.

关键词： Active disturbance rejection control,Backstepping approach,Rodless pneumatic cylinder,Trajectory tracking

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Process of back pressure deep drawing with solid granule medium on sheet metal

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Journal of Central South University 2014年第7期21卷 2617-2626页

作者：董国疆赵长财曹秒艳 College of Vehicles and Energy Yanshan University Key Laboratory of Advanced Forging & Stamping Technology and Science of Ministry of Education of China (Yanshan University) National Engineering Research Center for Equipment and Technology of Cold Strip Rolling (Yanshan University)

The experimental die apparatus of the solid granules medium forming on sheet metal was designed and *** parts,such as conical,parabolic,cylindrical and square-box-shaped components,were successfully trial-produced as *** to the analysis of the changing trends of the cross-section shape and the wall thickness during the process,it can be found that the shape of the free deformation zone of the sheet metal,which is the most critical thinning area,can be described as an approximately spherical *** to this forming feature,back pressure deep drawing technology with solid granules medium on sheet metal was proposed to restrain drastic thinning at the bottom of the part through the joint friction effect of solid granules medium,the back pressure tringle and the sheet ***,the deep drawing limit of the sheet metal is significantly *** order to fabricate thin-walled rotary parts with great drawing ratio and complex cross-sections,a finite element model based on the material property test of the solid granules medium was established to optimize the scheme of the back pressure deep *** effects on the forming performance of sheet metal from back pressure load and the approach of blank holding control were analyzed through this model.

关键词： solid granules medium forming drawing sheet metal finite element simulation

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Sliding mode control for network control systems with packets dropout

Sliding mode control for network control systems with packet...

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第三十四届中国控制会议

作者： Luyang Zhang Ling Zhao Li Li Institute of Electrical Engineering Yanshan University Hebei Province Key Laboratory of Heavy Machinery Fluid Power Transmission and Control Yanshan University Key Laboratory of Advanced Forging & Stamping Technology and Science (Yanshan University) Ministry of Education of China College of Mechanical Engineering Yanshan University

ISBN: (纸本)9781467374439

In this paper, we investigate the problems of stabilization of networked control systems with packets dropout via delta operator approach. A sliding mode controller is constructed to analyze the stochastic stability of the closed-loop networked control systems. The process of packets dropout is modeled as a Bernoulli process. Sufficient LMI conditions are developed to guarantee the existence of the discrete linear sliding surfaces. By solving the conditions, a linear sliding surface is characterized and a sliding mode controller is designed. Simulation results are given to demonstrate the effectiveness of the proposed approach.

关键词： Sliding mode control,network control systems(NCSs),delta operator system,packets dropout

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