Abstract: In the paper, an approach, based on bounded-error estimation via interval analysis, is presented to identify viscous damping coefficient and Coulomb friction coefficient of such-rod pumping system of directional well. The approach assumes the error of colleted output data of suck-rod pumping system is bounded. Hence, the problem of parameter estimation can be viewed as that of set inversion, which will be effectively solved via interval analysis. The main advantage of the proposed method in comparison with the traditional estimation methods is that, as it is global, it bypasses the problem of initialization. Moreover, the method avoids amount error due to transformation of measurement output data. An identification example is given to show the correctness and efficiency of the proposed method.
Abstract: This paper proposes a new method of motor fault detection. ML Estimation is proposed as a key technique for signal processing. The stator current is used data for motor fault analysis. ML Estimation is generally applied to estimate signals for nonlinear model. The expectation is that the method can provide information for fault analysis. The method is tested on 3 different motor conditions: healthy, stator fault, and rotor fault motor at full load condition. Based on experiments, the method can differentiate conditions clearly and be also able to measure fault severity levels.
Abstract: Hydrostatic transmission with secondary regulation based on constant pressure network (CPN) has the advantages of stepless speedless regulation, high power density, etc. This paper applies it to a Towbarless Tractor (TLT) transmission system and aims to improve its wheel control precision. A control strategy for TLT wheel coordination under driving condition is proposed and simulation is carried out in our facing-backward simulation model. The results show that good control performance can be realized by the control strategy. It can effectively achieve the goal of antislip. Moreover, the simulation analysis provides significant reference values for further development of wheel coordination controllers.
Abstract: To figure out the problem of turbulence simulation of underwater ammunition fuze turbine numerical simulation, respectively, realizable k-ε turbulence model and SST k-ω turbulence model are used for two-phase flow numerical simulation of the turbine rotation. The analysis compared the calculation results of the two turbulence models. The results showed that: the cavitation scale obtained from realizable k-ε turbulence model is shorter than that of SST k-ω turbulence model; turbine surface pressure distribution trends are similar of this two model, the results of realizable k-ε turbulence model are bigger than SST k-ω turbulence model; the turbine axial pressure coefficients using realizable k-ε turbulence model are also bigger than that of SST k-ω turbulence model, and the deviation increases with the speed increase.
Abstract: A operation stability prediction model faced to wind power equipment group based on Internet of Things(IOT) is research. It’s beneficial to improve the operation stability of key equipment group and promote the emerging IOT technology application in equipment maintenance. The prediction model mainly including: based on IOT constructing the system of remote online sample acquisition and operation stability prediction; proposing operation trend prediction algorithm based on energy decoupling faced to wind power rotating machinery, realizing of operation trend feature extraction of equipment group; constructing operation stability trend prediction model faced to equipment group. Operation trend feature is used to predict fault trend of wind power in order to ensure safe and stable operation of wind power group.
Abstract: This paper presents an analysis on the effect of ply angle for laminated composite plates on wind induced vibration. With Hamilton’s principle and the Rayleigh-Ritz method, the equation of motion for the wind induced vibration is derived. The displacements in time domain and the mean-square value of the transverse response under wind pressure are studied for laminated plates with different ply angles. From the numerically simulation results it is seen that the ply angle of the laminated plate can significantly affect the wind induced vibration. For different rectangle plate the optimal ply angles of minimum displacement is different. The analytical methodology in this paper can be expanded to other kinds of random vibration such as water flow induced vibration.
Abstract: Hydraulic motor is one of the elements with a high occurrence rate of failure in hydraulic system of amphibious assault vehicles. When the fan pump leakage reaches the limit value allowed, the fan pump should be renewed or overhauled. Through an analysis of the influencing factors that affect fan pump leakage of amphibious assault vehicles, this article establishes a support vector machine (SVM) regression model for fan pump leakage and gets a maximum relative error of 4% between the fitted value and the measured value of fan pump, which offers more reliable evidence for scientific determination of renewal period or overhaul period of fan pump.
Abstract: For the spectrum characteristics of the motor vibration, the vibration fault diagnosis method of motor rotor rubbing based on wavelet packet transform and real-valued negative selection algorithm is put forward. Using wavelet packet analysis to energy analysis of rotor rubbing and extracting the fault feature vectors, then by real-valued negative selection algorithm to identify the normal and failure mode eigenvectors. The experimental results show that with this method all the rotor rubbing faults can be detected comprehensive and rapidly. This method has high feasibility of the wavelet packet analysis and real-valued negative selection algorithm in the rotor rubbing fault diagnosis.
Abstract: The natural frequencies of the reduced scale model are higher than that of the prototype, which make it quite difficult to conduct the experimental research on the dynamic characteristics of the rotor system by using normal rotor model. Aiming at this problem, this paper has deduced the similarity criterion of abnormal rotor model based on equation analysis, and the dynamic similarity conditions between abnormal rotor model and the prototype are also discussed. Next, the mass matrix and flexibility matrix are presented based on the lumped parameter model of the rotor system. Finally, the similarities among normal rotor model, abnormal rotor model and the prototype are comparatively analyzed. The results show that the natural frequencies of abnormal rotor model and that of the prototype are all the same while the radial scaling factor is the square of the axial scaling factor. And it provided the theoretical basis for experimentally studying the dynamic characteristics of the rotor system.
Abstract: Applying the viewpoints and methods of sport biomechanics, and from the conservation of momentum, we have analysed Sanda rotation technique and elaborated on Sanda movement inertia mechanical characteristics and requirements, to make Sanda coaches and athletes on the basis of these laws of Sanda technique teaching and training, and to achieve the best results of training and sparring competition results.