Research On Dynamic Monitoring Method Of Lifting Load Of Multi-rope Friction Hoister

Wire ropes tension is one of the main safety parameters of coal mine safety improvement,which directly affects the mine safety production.However,wire ropes endure vibration and shock in lifting process of hoisters in coal mine,which interferes with measurement of wire rope tension and lifting load seriously.Aiming at the complexity of tension monitoring of wire ropes in dynamic process,this paper studies the dynamic monitoring method of lifting load of multi-rope friction hoist.This paper designs an oil cavity sensor installed between the piston and slider of balance cylinder of multi-rope friction hoist.The wire rope tension signal is converted into the pressure signal between piston and slider to measure,which eliminates the safety hazard by tension sensor in series with wire rope to measure the tension,and improves the safety of lifting load of the hoist dynamic monitoring.In this paper,oil cavity structure is designed in the sensor which converts the measured signal into oil pressure signal to measure.By this way,the influence of measured signal pressure fluctuation on the measurement is eliminated,which solves the problem of the interference of transient tension on wire rope effective tension measurement during the lifting process.In this paper,the weakening vibration model of oil cavity sensor is established by using the method of concentrated parameter equivalent,and two critical frequencies is determined which affect the weakening vibration characteristics of the sensor,and the control method of low frequency noise is obtained.By using the pressure fluctuation equation in the flow field,the law of pressure distribution is got,and the cutoff frequency of the high-order wave is determined,which can further explain attenuation law of the high-frequency pressure wave of the oil cavity.Based on the energy consumption of the damping,the gap structure is set in the oil cavity to increase damp for controlling the pressure amplitude in the oil cavity,which contributes for eliminating the influence of transient tension fluctuation on the effective tension measurement of the wire rope.At the same time,the oil cavity structure of the sensor is improved,and the pressure fluctuation amplitude of oil cavity is controlled by the small hole damping,which avoids the influence of the oil cavity resonance on the strain zone signal.In this paper,the LMS Virtual.lab simulation software is used for modal analysis and the fluid and solid coupling simulation based on the modal space to verify the correctness of the weakening vibration model of the sensor.At the same time,by changing the simulation parameters,the influence of the oil cavity structure parameters and the fluid type on the vibration characteristics of the oil cavity sensor is studied for guiding the structural design of the oil cavity sensor.A test of the new sensor for linearity testing,calibration and temperature rise is carried out by laboratory,which ensures the sensor measurement accuracy;According to the thermal expansion characteristics of the crystal and the equation of state,the pressure variation of the sensor at different temperatures can be obtained as the basis of temperature compensation;The calibration method of the sensor is put forward,and the filter vibration characteristics of the new sensor are verified by comparing with the oil pressure sensor and the universal pressure block sensor;Finally,a new type of sensor based on the wire rope test platform is developed,through the application in the coal field,indicating that the new sensor can not only effectively monitor the rope tension,calculate the lifting load,you can also use the measurement data on the hoist on-site fault diagnosis.