Analysis Of Hoist Dangerous Load And Study On Its Prewarning System

Mine hoisting is an important link of coal production and directly related toproduction safety and efficiency. However, by so far safety incidents during hoistingrepresent a large proportion of the mechanical and electrical accidents in mines, andlots of them are caused by Hoist Dangerous Load. So study on dangerous loadwarning system was carried out on the basis of kinetic analysis on dangerous load,which was to upgrade hoist safety by identification and Prewarning of dangerous load.In kinetic analysis of dangerous loads, a vibration model was built, whichincluded a container, a wire rope, useful load, etc. With modal analysis method baseon Ritz Series, vibration of the wire rope while overloading, incomplete unloading,container jamming, and rope slack take place was researched. Relations betweendifferent types and varying degrees of dangerous load and rope vibrationcharacteristics was found, which could provide necessary foundation for parametersselection for load monitoring and the identification of dangerous loads. With actualexamples, Rayleigh ratio effectiveness for fundamental frequency estimation of therope and container was verified, Ritz Series convergence during the solving of elasticrod vibration problems was proved.Genetic algorithms based on outside point penalty function was adopt in thestudy on constrained optimization research of multi-sensor fusion system for hoistloads. Under the premise that the system validity had been achieved, generalized costof the system was minimized. An information fusion experiment device was built totest hoist loads, which could imitate and record kinds of dangerous load models.Based on D-S evidence theory, an information fusion model was built; uncertainty ofmulti-sensor information was reduced. Effectiveness of this theory for the modelidentification of Hoist Dangerous Loads was verified with the actual faults seriousoverloading and slight container jamming.Three methods which are wavelet de-noising, EMD de-noising based oncorrelation coefficient, energy period/average density, EEMD de-noising were appliedin the processing of hoist load signals. They were compared on the respects ofreal-time performance, adaptability and influencing factors, etc. It was pointed outthat EMD de-noising method has the comprehensive advantages and is more suitablefor the dangerous load Prewarning system. Lipchitz method based on wavelettransform modulus maxima was used in singularity analysis on hoist loads, which showed that it could catch and locate the singular feature during the process of ropeslack, container jamming, loading and unloading, and reflect impact strength.A dangerous load warning system was built based on production rules. The modeof browser/server based on web was adopted in expert knowledge acquisition.Knowledge fusion was realized with the methods of influence diagram and maximumlikelihood estimation. Data-socket technology based on DSTP protocol was used inthe realization of expert online service. For field hoist load monitoring and protectingdevice which is directly link to the dynamic library of the expert system, mechanical,electrical and software parts were designed. Sensors selection was achieved with leastsquare estimation and F-test methods. How the input impedance, radiation type andeffective length of an antenna affect wireless communication was illustrated. Forseveral parts of the system that works in the environment where there could beexplosive mixtures, flameproof explosion-proof design was conducted from therespects of explosion-resistance and explosion-proof performance. Hoist loadmonitoring devices developed have been applied in mine field.