Papers by Author: Wen Jun Meng

Abstract: This paper presents a multidiscipline coupled-field analysis method to study the temperature distribution of an automotive magnetorheological brake with double coils placed on side housing. First, a new apparent viscosity definition was employed to connect the communication of magnetic field, fluid dynamics, and temperature field. Then, the dynamic model of the brake was established to evaluated the rotation law of the brake disk and the total brake time. At last, multi-physics modeling was established with sequencetial coupling methods, which were based on the Maxwell equations, Naiver-Stokes equations and conjugate heat transfer equations. The results indicate that the overall temperature distribution of the MR brake is relatively uniform at a zero magnetic field during the steady state, and the maximum temperature difference is about 9.7°C. During braking process, the temperature variation regularity for radial and axial points is basically the similar, and the maximum temperature appears in the axial working gap, the maximum value is 113°C which is less than the maximum allowable working temperature of the chosen MR fluid. The results can be taken as reference to the design of the MR brake.

Abstract: The paper analyzes the characteristics and the situation of the control of multivariable coupling system, combining improved PID neural networks with PSO algorithm, and finally designs a suitable controller model. To achieve a controller model, an initial structure of PID neural networks is established in the first place. Then weights in the network is initialized by PSO algorithm and optimized by improved gradient descent algorithm. A simulation, MIMO coupling system, prove this controller has such characteristics with short time and high precision. The research of the paper provides a new idea and approach for control of complex coupling system.

Abstract: To design high quality and efficiency discharging system, according to the analysis of strength and the study of discharging principle for bulk materials between general silo and central cone silo with discharge arms, their theoretical model and simulation model are established. Based on the theoretical calculation and simulation results, it is proved that the central cone silo which has a rotary discharge arm or discharge arms revolving around the central cone has advantages with discharging the difficult bulk materials, which could efficiently prevent the harmful discharging such as bridging, rat-hole and so on. Controlling the outflow of bulk materials, it is easy to automatically discharge the bulk materials and improve the efficiency of silo system. The result shows that the central cone is practical and the discharging way provides a new program for solving technology problems in discharging the difficult bulk materials.

Abstract: The paper established the whole system for stress monitoring and safety assessment of metal structure aimed at kinds of cranes, based on LabVIEW software platform. Introduced function and composition of each subsystem in detail. The system consists of data acquisition, signal analysis and processing, data storage, historical data inquiry, safety assessment, critical security warning and estimation of fatigue life. The system adopted the wireless transmission method at the same time. As a result, feasibility of the system was proved by the case applied and it offered a convenient method for monitoring. The successful application of stress monitoring and safety assessment in the metal construction of large crane equipment makes foundation for its application in projects, which has great practical value.

Abstract: Data mining is a broad term used to describe various methods for discovering patterns in data. A kind of pattern often considered is association rules, probabilistic rules stating that objects satisfying description A also satisfy description B with certain support and confidence. In this study, we first make use of the first-order predicate logic to represent knowledge derived from celestial spectra data. Next, we propose a concept of constrained frequent pattern trees (CFP) along with an algorithm used to construct CFPs, aiming to improve the efficiency and pertinence of association rule mining. The running results show that it is feasible and valuable to apply this method to mining the association rule and the improved algorithm can decrease related computation quantity in large scale and improve the efficiency of the algorithm. Finally, the simulation results of knowledge acquisition for fault diagnosis also show the validity of CFP algorithm.

Abstract: A new hybrid control scheme combining input shaping technique with robust sliding mode control is proposed for a gantry crane system. A cascade sliding-mode controller is designed to control the trolley position and eliminate the sway of load. The transient vibration is reduced further for safety problems by the input shaping technique which utilizes zero-vibration-derivative (ZVD) robust input shapers. This method can not only realize the accurate position of the trolley and eliminate the sway of the load and residual vibration, but also completely eliminate the chattering of conventional sliding mode control and improve the robustness of system. The simulation results proved its effectiveness.

Abstract: Because of the resistances to the belt’s motion in belt conveyors mainly caused by friction and frictional wear of the belt being one of key factors to effect its service life, the paper gives a simple qualitative investigation of frictional characteristic of the belt from its material behavior. Using stimulant coefficient of friction, it could make quantitative analysis for the resistances to the belt’s motion caused by friction etc, and design a belt conveyors synthesized testing system, the aim of the system is to test stimulant coefficient of friction under more type conveyors and more operating modes. Measurement and control of the system is based on VI(Virtual Instrument) software——LabVIEW, and in consequence it simplifies the hardware of the system, it also enhances human-computer interaction of the system’s operational interface.