Advanced Materials Research Vol. 619

Abstract: In order to fine working states of a continuous miner hydraulic system, diagnose quickly and effectively its faults, reduce failure rate, save maintenance time and improve the reliability and productivity of a continuous miner, the GA-PSO hybrid optimization method of fuzzy neural network is used in fault diagnosis of a continuous miner hydraulic system in the paper, a intelligent fault diagnosis expert system of a hydraulic system is designed by means of taking VC 6.0 as the programming platform, using SQL SERVER 2000 as database, embedding MATLAB7.1 in the internal. The system is simple in man-machine interface and good in man-machine conversation, capable of analyzing accurately and judging properly failures of a continuous miner hydraulic system.

Abstract: Dynamic characteristics of the hydraulic control system for the cutting system of roadheaders are very important for analyzing the working performance. This paper supplies the modularization design method for hydraulic control system of cutting system of roadheaders. It utilizes the Matlab/Simulink to establish the mathematical model for each hydraulic components of the cutting system. And the hydraulic control system model is simulated by Matlab/Simulink. It’s useful for predicting and optimize the dynamic response of the hydraulic control system.

Abstract: A hydraulic Control Loading System (CLS) based on velocity-loop was developed and installed on our flight simulator earlier days, but the CLS cannot keep stable in some conditions. This problem is discussed in this paper. The mathematical model of velocity-loop-based CLS is firstly developed with the method of transfer function block diagram. Then, system’s stability conditions are put forward using Roth criterion based on the system model developed. At last, the experiments proves the stability

Abstract: In order to estimate the stability of the roadheader rear support system, took the heavy cantilever roadheader of a coal company as the research object, rigid-flex coupled dynamic model of its rear support system was established based on Pro/E, ADAMS and ANSYS. The hydraulic control system model of rear support was researched in EASY5. These two models built the mechanical-hydraulic coupling system. Analysed the mechanical dynamic simulation results and verified the reliability of hydraulic system when the co-simulation of rear support was made.

Abstract: The electrode feeding mechanism and the feeding speed control system of the electroslag remelting furnace are studied. The electrode feeding mechanism is designed based on the electro-hydraulic proportional control technique, and the mechanism’s three-dimensional model is established. The electrode feeding mechanism’s electro-hydraulic proportional control system is simulated. The basic feeding speed model and the error-correction feeding speed model are established; and the S style speed control curve of the electrode feeding system is designed. Experiments were carried out; the system control curves and the experimental production dissection results were obtained. It was found that, the electrode feeding system and the feeding speed control system studied in this paper met the craft procedure and technique requirements of large electroslag remelting furnace, and the method’s validity was verified.

Abstract: Snake mobile conveyor is a special structure new conveyor, its body composed of a number of independent frames which relative rotation and achieved conveyor’s horizontal turning. In order to insure smoothness and controllability of turning, system executed predict the feedback control on the steering fuel tank using a hydraulic-assisted steering system. Control programs: the establishment of the virtual prototype of the machine - record tractor turning angle - calculation orbit of tractor frame - to calculate the steering cylinder corresponding stretched time and displacement - the controller to control assisted steering - Complete trajectory , and simulation analysis proved that this control method is feasible.

Abstract: Hydraulic cylinder is an important actuator in hydraulic system, affecting the system running correctly and effectively. It’s closed and difficult to observe the failure symptoms, and result the difficulties of fault diagnosis and elimination for hydraulic cylinder. In this paper, a fault detection instrument and system for hydraulic cylinder are developed to diagnose the fault mode through position and pressure signals and infer decision based on FMEA base.

Abstract: High temperature has great influence on the rational clearance between the spool and the sleeve, even cause to the valve not working. So it is necessary to research the flow rate control valve’s thermodynamic characteristics. The 45 steel’s thermodynamic characteristic is compared with the GH783 alloy’s in this paper. The results show that the temperature raised quickly near the orifice, the time that the 45 steel takes to reach to thermal equilibration is shorter than the GH783 alloy’s. The 45 steel’s deformation tendency is similar to the GH783 alloy’s, but the 45 steel’s deformation quantity is larger than the GH783 alloy’s. At high temperature, the flow area of the valve made of GH783 alloy has little change, which has little affluence on the valve’s regulating characteristic.

Abstract: The study on an advanced equipment of a new pumping unit is presented to satisfy the mining technology demands of large load, long stroke and low pumping speed during petroleum exploitation process. The method of using a full hydraulic system drive rather than the traditional way is adopted to overcome the disadvantages in a traditional oil production equipment such as complex mechanical structure, large volume,many transmissions, low efficiency and high manufacturing cost. In addition, the hydraulic circuit which is made up of an accumulator, a hydraulic motor and two hydraulic pumps is used to realize power recovery for energy saving. The mechanical mathematical model and the hydraulic one of a novel hydraulic oil production mechanism were established and analyzed. Good results are eventually obtained. This equipment has been the national patent.

Abstract: The reversing valve is a vital servo component in the hydraulic system, which reversing the movement of the execute component by the movement of the valve core to change on-off of the hydraulic channels. The model for a three-position four-way electromagnetic reversing valve used in some hydraulic system was established based on AMESim. The simulation operation results showed that the model had realized the same function with that of the actual valve, and had been consistent with the actual one on dynamic characteristics. The established of the model and the dynamic simulation analysis laid foundation for the hydraulic system operation reliably and effectively.