Theoretical coupling longitudinal-transverse model and experimental verification of transverse vibration of rope for multi-rope friction hoisting system

Using the mass of time-varying length balance rope focused on the hoisting conveyance, the coupling longi- tudinal-transverse model of mine friction hoist was established by using of the Hamilton＇s principle. The modified Galerkin＇s method was used to discretize partial differential Eqs. The mine hoisting system was used to the example to analysis the relation between the load, velocity and transverse vibration of rope. The in situ tests were illustrated to evaluate the proposed mathematical model. The results showed that the modeling method can well represent the transverse vibration of rope.

Study on the instability of airflow in mine hoisting-shaf

In order to discover the airflow pattern in mine shaft which outfitted with hoist equipment （HE）, this paper set up the physical model and anatomized the piston-wind caused by hoist equipment, and researched the flow field and velocity field around the hoist equipment during its moving process, and analyzed the airflow around single and couple hoist equipment as well as decisive range of piston effect and additional effect of hoist equipment to ventilation system. Research conclusion indicate that during hoist equipment movement, airflow pattern changes repeatedly because of the influence of pis-ton effect from hoist equipment, and the study of airflow stability in shaft is the foundation for the stability of ventilation in mine.

Research and Application for the Regularity of Distribution about Curvature Radius and Curvature Center of the Linkage Point Track in a Link Mechanism

It is illustrated that there exists an inflection circle on the linkage rigid body by the principle of relative motion. Confirmed methods of the inflection circle, curvature radius and curvature center of the point track on the linkage rigid body are given in the case of the different contact type of move instantaneous center line and static instantaneous center line. The regularity of distribution of curvature radius and curvature center of the point track is researched. The identification methods called determination parameters and auxiliary vertical line of the diameter and direction of the inflection circle in the four bar mechanism are pointed out. A design method of the crane hoisting mechanism is discussed in the end of this paper.

Research on Energy Efficiency Characteristics of Mining Shovel Hoisting and Slewing System Driven by Hydraulic-Electric Hybrid System

Mining shovel is a crucial piece of equipment for high-efficiency production in open-pit mining and stands as one of the largest energy consumption sources in mining.However,substantial energy waste occurs during the descent of the hoisting system or the deceleration of the slewing platform.To reduce the energy loss,an innovative hydrau-lic-electric hybrid drive system is proposed,in which a hydraulic pump/motor connected with an accumulator is added to assist the electric motor to drive the hoisting system or slewing platform,recycling kinetic and potential energy.The utilization of the kinetic and potential energy reduces the energy loss and installed power of the min-ing shovel.Meanwhile,the reliability of the mining shovel pure electric drive system also can be increased.In this paper,the hydraulic-electric hybrid driving principle is introduced,a small-scale testbed is set up to verify the feasibil-ity of the system,and a co-simulation model of the proposed system is established to clarify the system operation and energy characteristics.The test and simulation results show that,by adopting the proposed system,compared with the traditional purely electric driving system,the peak power and energy consumption of the hoisting electric motor are reduced by 36.7%and 29.7%,respectively.Similarly,the slewing electric motor experiences a significant decrease in peak power by 86.9%and a reduction in energy consumption by 59.4%.The proposed system expands the application area of the hydraulic electric hybrid drive system and provides a reference for its application in over-sized and super heavy equipment.

Research on temperature rise of hoisting machine disk brake

A mathematical model and finite element model for analysis of temperature rise of the hoisting machine brake sys- tem was constructed, limit conditions were defined, and the law of temperature rise of brake shoes during emergent brake course was analyzed and calculated by using finite element software. By analyzing the calculation results, the law of tempera- ture change of surface of brake disk and shoes during the braking process was found. The law of brake shoes surface tempera- ture distribution and the law of temperature change along with thickness of brake shoes at brake time 0.5 s, 1.0 s and 1.5 s was analyzed. A hoisting machine emergent braking test was carried out. Finally, the author concluded that velocity rebound in the process of hoisting machine emergent brake is due to decreased friction coefficient caused by the temperature rise of the brake shoes surface.

Study of Movement Reliability for Hoisting Jack under a Rocket Launcher Vehicle

The transmission mechanism of a jack is required to support the combat vehicle reliably within a very short time. So reliability research is very important because the mechanism completes motions required under the conditions within limited time. If the transmission mechanism of the jack supports the rocket launcher steadily, it needs to go through several stages as follows ： unlocking, starting, operating, braking, stopping, fixing position and locking. The transmission mechanism of the jack is a complicated and single degree of freedom mechanical system; it can be considered an imaginary mechanical model that has an equivalent moment of inertia and equivalent torque. According to the characteristics of each supporting stages, dynamics equations of the mechanism are established. At the stages of starting and operating, a driving moment and resistance moment are dealt with for a Normal distribution. The design principles for movement reliability of completing action are established and the design principles for time reliability of completing action within a limited time are established. Finally, movement reliability of the transmission mechanism of the jack is 0. 9 852, according to our calculation. Reliability of time to complete action is 0. 9 943.

FEASIBILITY AND EXPERIMENT ANALYSIS OF FOUR-ROPES FRICTION HOIST WITHOUT ROPE GROOVES CUTTING

Based on theoretical analysis and experiment, when the difference between the ropes length is ensured, the radius difference between the rope grooves and the difference of the rope strain of a double rope friction hoist will decrease with the increasing of hoisting times. Then the rope grooves cutting are not needed. If the connection form of the ropes or the structure of the frictional wheel of a four ropes friction hoist are changed into as a double ropes hoists, the hoist rope grooves will not need to be cut as well, and the working time will be saved and the service life of the rope lining will be lengthened also.

利用模拟退火技术求解多Hoist调度问题(英文)

多 Hoist调度在许多制造过程的设计与控制中是一个关键问题 .当 Hoist数与工作台数很大时 ,求解调度问题非常困难 .建立了多 Hoist调度问题的数学模型 ,并利用模拟退火算法提出了一种启发式求解方法 .随机模拟的大量算例表明 ,该启发式方法十分有效 。

Fault diagnosis of a mine hoist using PCA and SVM techniques

A new method based on principal component analysis (PCA) and support vector machines (SVMs) is proposed for fault diagnosis of mine hoists. PCA is used to extract the principal features associated with the gearbox. Then, with the irrelevant gearbox variables removed, the remaining gearbox, the hydraulic system and the wire rope parameters were used as input to a multi-class SVM. The SVM is first trained by using the one class-based multi-class optimization algorithm and it is then applied to fault identification. Comparison of various methods showed the PCA-SVM method successfully removed redundancy to solve the dimensionality curse. These results show that the algorithm using the RBF kernel function for the SVM had the best classification properties.

Frictional heat analysis of mine hoist and numerical simulation on temperature field of gasket

The frictional performance of gaskets is greatly affected by frictional heat in operational mine hoists. Based on frictional mechanism and heat transfer theory, the mathematical model of the temperature field of the PVC gasket in an operational mine hoist was investigated, a numerical simulation using ANSYS is presented and the distribution of the temperature and heat flux were studied under basic assumptions. The results show that the temperature gradually decreases as the radius of the model increases and the isotherms are arcs of concentric semi-circle. The heat flux is of bilateral symmetry in the model and decreases radially. The theoretical values correspond with the measured values for a short time (τ≤ 100 s) when the steel wire rope slides.

Hoist technology of a new agile naval gun shell-feeding system

Shell-feeding velocity is an important factor affecting naval gun shooting capacity. An agile shell-feeding system was designed to ensure quick implementation of the shell-feeding task. Based on composition of the agile shell-feeding system, hoist technology was studied. Working principles were discussed and the hydraulic pressure system of the hoist was constructed. The hydraulic pressure cylinder and the accumulator were analyzed and calculated. Finally, PRO/E and ADAMS were used to simulate the hoist and its hydraulic system. It was found that this type of virtual prototype provides a good method to actualize a physical prototype.

Inhibition characteristics of circulating current in parallel inverter driving system of mine hoist

This research investigated the outputting circulation current inhibition characteristic which are controlled by the instantaneous feedback voltage in inverter parallel driving of the mine hoist. We established a transfer function of the parallel inverters controlled by the close-loop adjustment of instantaneous voltage feedback. The influence of the parameters of the close-loop feedback circuit to the inhibition effects to the outputting circulation current is observed. After analyzing the circulating current inhibition characteristics, the proportion integration （PI） controller is introduced into the close-loop adjustment by instantaneous voltage feedback. The characteristics equation is gained to determine the PI parameters by drawing the Bode plots. The inhibition effects of the proposed controller are examined by the established simulation model of parallel inverter system. The harmonic distortion rate at the outputting voltage frequency value of 4, 10, 20, 41 and 50 Hz, are all lower than 2.32 % by the instantaneous outputting voltage feedback.

A new method to accurately measure the drift of shipborne floated gyro

Shell-feeding velocity is an important factor affecting naval gun shooting capacity. An agile shell-feeding system was designed to ensure quick implementation of the shell-feeding task. Based on composition of the agile shell-feeding system, hoist technology was studied. Working principles were discussed and the hydraulic pressure system of the hoist was constructed. The hydraulic pressure cylinder and the accumulator were analyzed and calculated. Finally, PRO/E and ADAMS were used to simulate the hoist and its hydraulic system. It was found that this type of virtuaU674.7l prototype provides a good method to actualize a physical prototype.

Theoretical analysis of thermoviscoelastic contact between friction lining and wire rope in mine friction hoists

Serious accidents of mine hoists caused by high-speed sliding between friction lining and wire rope are often seen in coal mines.In order to solve this problem,we analyzed the contact characteristics between friction lining and wire rope.Then we carried out a dynamic mechanical analysis(DMA) to explain the change in mechanical properties of the friction lining as function of temperature and load frequency and found that temperature has a stronger effect on the mechanical properties than the frequency.We used multiple regression analysis to obtain the thermoviscoelastic constitutive relations of the friction lining.As well we derived the analytic solution for the thermoviscoelastic contact radius and pressure by combining the theory of viscoelastic contact mechanics with thermoviscoelastic constitutive relations.

Hydrodynamic Characteristics of Three-Bucket Jacket Foundation for Offshore Wind Turbines During the Lowering Process

The three-bucket jacket foundation is a new type of foundation for offshore wind turbine that has the advantages of fast construction speed and suitability for deep water. The study of the hoisting and launching process is of great significance to ensure construction safety in actual projects. In this paper, a new launching technology is proposed that is based on the foundation of the three-bucket jacket for offshore wind turbine. A complete time domain simulation of the launching process of three-bucket jacket foundation is carried out by a theoretical analysis combined with hydrodynamic software Moses. At the same time, the effects of different initial air storage and sea conditions on the motion response of the structure and the hoisting cable tension are studied. The results show that the motion response of the structure is the highest when it is lowered to 1.5 times the bucket height. The natural period of each degree of freedom of the structure increases with the increase of the lowering depth. The structural motion response and the hoisting cable tension vary greatly in the early phases of Stages Ⅰ and Ⅲ, smaller in Stage Ⅱ, and gradually stabilize in the middle and late phases of Stage Ⅲ.

Mine-Hoist Active Fault Tolerant Control System and Strategy

Based on fault diagnosis and fault tolerant technologies, the mine-hoist active fault-tolerant control system (MAFCS) is presented with corresponding strategies,, which includes the fault diagnosis module (FDM), the dynamic library (DL) and the fault-tolerant control module (FCM). When a fault is judged from some sensor by FDM, FCM reconfigure the state of MAFCS by calling the parameters from all sub libraries in DL, in order to ensure the reliabil- ity and safety of mine hoist. The simulating result shows that, MAFCS is of certain intelligence, which can adopt the corresponding control strategies according to different fault modes, even when there are quite difference between the real data and the prior fault modes.

Application of Over-Winding and Over-Falling Buffer Unit in Coal Mines of Datong Coal Group Company

Dynamic force of BS buffer unit in the enwinding hoisting system is calculated, and the buffer unit is in- stalled and tested. The result shows that this buffer unit is accurate in its regulated braking force and convenient in ad- justment and restoration. It can be repeatedly used as a bumper for both over-winding and over-falling without replacing any parts, providing an applicable device for safety operation in coal mining.

Electrochemical corrosion behavior of steel wires in a coalmine with a corrosive medium

A6×19 point-contact hoisting cable was used as our research object to examine the progress of corrosion of steel wires in a laboratory,simulating the actual working conditions in a coalmine.An electrochemical method was used to investigate the corrosion behavior of steel wires with different surface treatments of a corrosive acid solution.The results show that anode activation of steel wire mainly occurs during pre-corrosion,where the anode activation process of bare steel wires is the fastest as is their corresponding corrosion speed,while the anode activation process of oil coated steel wires and their corresponding corrosion speed are the lowest.During the intermediate and late immersion periods, a passive film is generated on the surface of steel wires,which are gradually damaged with the passage of time.Local pitting corrosion occurs easily on the surface of steel wires with a high-polarization potential. Suitable equivalent circuits were chosen to fit the electrochemical impedance spectroscopy（EIS）of steel wires over various corrosive times and different surface treatments,which indicate good fitting results. The double electrical layer charge-transfer resistance increases in the sequence：bare steel wire, untreated steel wire and oil coated steel wire and their corrosion resistance decreases in turn,which is consistent with their polarization curves.The oil layer provides a certain protective effect on untreated steel wires,but its effect is not entirely clear.