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Zhao J.,Hebei Provincial Key Laboratory of Heavy Machinery Fluid Power Transmission and Control | Zhao J.,Key Laboratory of Advanced Forging and Stamping Technology and Science | Zhang C.,Hebei Provincial Key Laboratory of Heavy Machinery Fluid Power Transmission and Control | Zhang C.,Key Laboratory of Advanced Forging and Stamping Technology and Science | Liu W.,Yanshan University
ICIC Express Letters | Year: 2015

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 Source


Feng J.C.,Yanshan University | Feng J.C.,Northern Heavy Industries Group Co. | Kong X.D.,Yanshan University | Kong X.D.,Hebei Provincial Key Laboratory of Heavy Machinery Fluid Power Transmission and Control | And 3 more authors.
Applied Mechanics and Materials | Year: 2014

This paper researches and analyzes the modeling of electro-hydraulic proportional servo system to improve the characteristics of forging hydraulic servo control system and meet their requirements of forging a variety of materials. Based on robust compensator design, PID control strategy is proposed with uncertain disturbance of hydraulic press hydraulic servo system and the response characteristics of the system is simulated and analyzed. The results show that hydraulic press servo system which uses robust compensator has better performance than the traditional PID control and the chattering is eliminated. The test results and simulation results are compared by building simulation test system of 60MN hydraulic press electro-hydraulic proportional control system. © 2014 Trans Tech Publications, Switzerland. Source


Liu S.,Hebei Provincial Key Laboratory of Heavy Machinery Fluid Power Transmission and Control | Liu S.,Yanshan University | Yang M.,Hebei Provincial Key Laboratory of Heavy Machinery Fluid Power Transmission and Control | Yang M.,Yanshan University | Zhang W.,Yanshan University
Proceedings of 2015 International Conference on Fluid Power and Mechatronics, FPM 2015 | Year: 2015

Aiming at the problem of multi-fault identification method of axial piston pump, a new method combining correlation dimension and support vector machine was proposed. Firstly, the envelope demodulation was performed to several typical fault vibration signals of pump by using wavelet packet decomposition and Hilbert transform method. Then, the useful signals corresponding to feature band were obtained. Secondly, using the embedded dimension as characteristic attribute, the correlation dimension feature information of the useful signals was extracted by correlation dimension analysis method. At the same time, the feature sample set consists of the correlation dimension feature information and the energy feature information was built. Finally, the feature sample set was utilized as input, and the multi-fault modes of the axial piston pump were identified by support vector machine. Moreover, the experiments were respectively performed to the pump including slipper wear, loose slipper failure and central spring failure. The results confirmed that the fault recognition accuracy of SVM can be improved, and the faults can be effectively identified. © 2015 IEEE. Source


Kong X.,Yanshan University | Kong X.,State Key Laboratory of Fluid Power Transmission and Control | Kong X.,Hebei Provincial Key Laboratory of Heavy Machinery Fluid Power Transmission and Control | Cao Y.,Yanshan University | And 4 more authors.
Proceedings of 2015 International Conference on Fluid Power and Mechatronics, FPM 2015 | Year: 2015

For the vibration of the aero pipeline and the conveying pipeline exists universally and the vibration has effects on the pipeline life, the detection accuracy and the system stability, the research on the natural characteristic of the pipeline vibration has promising prospects. In this paper, the vibration mathematical model is built with the simple and practical Rayleigh-Ritz energy method to calculate the natural frequency and the mode of vibration theoretically. In addition, the finite element simulation model is built in the ADINA software to obtain the simulation results of the natural frequency. Moreover, the experiment is conducted through hitting the pipeline with the force hammer and the three directions acceleration detected by the three-axis acceleration sensor are obtained with the NI compact RIO acquisition equipment. The experiment data is processed with the Fast Fourier transform and power spectral density method involved with wavelet de-noising to get the tested natural frequency, which indicates that the theoretical analysis results are close to the experimental results. The researches above show that the Rayleigh-Ritz energy method is a simple, rapid and practical method to calculate the theoretically natural frequency of the pipeline vibration and the simulation model in ADINA can be used for vibration characteristic analysis with some proper boundaries conditions, which will provide the foundation for the vibration reduction theory research and the engineering application. © 2015 IEEE. Source


Ba K.,Yanshan University | Yu B.,Yanshan University | Yu B.,Hebei Provincial Key Laboratory of Heavy Machinery Fluid Power Transmission and Control | Cao Y.,Yanshan University | And 3 more authors.
Proceedings of 2015 International Conference on Fluid Power and Mechatronics, FPM 2015 | Year: 2015

The joint drive of quadruped robot, the highly integrated valve-controlled cylinder (HIVC), whose control performance could effect on the whole machine of the robot directly. In this paper, based on the structure principles of flow servo valve and pressure-flow servo valve, the mathematical models of above two kinds of servo valve are established to analyze their dynamical performance respectively. To ensure the accuracy of the analysis results, the flow gain of above two kinds of servo valve are unified, then using them for force close loop control of HIVC on the performance test platform of HIVC, the effects of step force and sinusoidal force on the force control performance of HIVC with different forward channel gain are tested, moreover, the force control performance of HIVC under different frequency position disturbance are tested. The test results indicates both flow servo valve and pressure-flow servo valve can realize force close loop control of HIVC, but by comparison, due to the load pressure which is existed in pressure-flow servo valve power level spool equilibrium process, the output flow decrease sharply with load force increasing, which can lead the load force control performance of HIVC which consists of pressure-flow servo valve is inferior to those which consists of flow servo valve. All the research conclusions can provide a theoretical and experimental foundation for the selection of servo control element of HIVC. © 2015 IEEE. Source

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