In the pump-controlled motor hydraulic transmission system,when the pressure pulsation frequencies seperately generated by the pump and the motor are close to each other,the hydraulic system will generate a strong pre...In the pump-controlled motor hydraulic transmission system,when the pressure pulsation frequencies seperately generated by the pump and the motor are close to each other,the hydraulic system will generate a strong pressure beat vibration phenomenon,which will seriously affect the smooth running of the hydraulic system.However,the modulated pressure signal also carries information related to the operating state of the hydraulic system,and a accurate extraction of pressure vibration characteristics is the key to obtain the operating state information of the hydraulic system.In order to extract the pressure beat vibration signal component effectively from the multi-component time-varying aliasing pressure signal and reconstruct the time domain characteristics,an extraction method of the pressure beat vibration characteristics of the hydraulic transmission system based on variational mode decomposition(VMD)is proposed.The experimental results show that the VMD method can accurately extract the pressure beat vibration characteristics from the high-pressure oil pressure signal of the hydraulic system,and the extraction effect is preferable to that of the traditional signal processing methods such as empirical mode decomposition(EMD).展开更多
Oblique cutting is a working condition in fully mechanized mining whose function is making it possible for coal shearer to cut coal wall.Coal shearer often exhibit large vibration amplitudes in oblique cutting since t...Oblique cutting is a working condition in fully mechanized mining whose function is making it possible for coal shearer to cut coal wall.Coal shearer often exhibit large vibration amplitudes in oblique cutting since the shearer is forced to be bent.In this study,dynamic behavior in oblique cutting for the coal shearer cutting unit gearbox(SCUG)is investigated experimentally based on National Coal Mining Equipment Laboratory of China.A new long wall mining test set-up consists of a test coal shearer and other auxiliary machines is developed for operating long wall coal mining process.Realistic oblique cutting process is developed,and vibration response will be more accurate since both cutting loads and test machine in this experiment are realistic.A data-acquisition system consisting of sensors,channel conditioner and computer is developed to capture three-dimensional vibratory accelerations.A test matrix which included various combinations of key cutting load parameters is executed under realistic oblique cutting loads within a wide parameter range to establish database.Experimental data is analyzed in time,domain and time-frequency domains for investigating the rules of dynamic behavior for SCUG.Beat vibration phenomenon and the coupling of gear mesh frequencies are found in experiment,resulting in local resonance and reduce fatigue life of SCUG.The influence of cutting load on beat phenomenon and frequency coupling is demonstrated at the end,and some conclusions are obtained.展开更多
基金National Natural Science Foundation of China(No.51675399)。
文摘In the pump-controlled motor hydraulic transmission system,when the pressure pulsation frequencies seperately generated by the pump and the motor are close to each other,the hydraulic system will generate a strong pressure beat vibration phenomenon,which will seriously affect the smooth running of the hydraulic system.However,the modulated pressure signal also carries information related to the operating state of the hydraulic system,and a accurate extraction of pressure vibration characteristics is the key to obtain the operating state information of the hydraulic system.In order to extract the pressure beat vibration signal component effectively from the multi-component time-varying aliasing pressure signal and reconstruct the time domain characteristics,an extraction method of the pressure beat vibration characteristics of the hydraulic transmission system based on variational mode decomposition(VMD)is proposed.The experimental results show that the VMD method can accurately extract the pressure beat vibration characteristics from the high-pressure oil pressure signal of the hydraulic system,and the extraction effect is preferable to that of the traditional signal processing methods such as empirical mode decomposition(EMD).
基金This paper was supported by the National Basic Research Program of China(2014CB046303).
文摘Oblique cutting is a working condition in fully mechanized mining whose function is making it possible for coal shearer to cut coal wall.Coal shearer often exhibit large vibration amplitudes in oblique cutting since the shearer is forced to be bent.In this study,dynamic behavior in oblique cutting for the coal shearer cutting unit gearbox(SCUG)is investigated experimentally based on National Coal Mining Equipment Laboratory of China.A new long wall mining test set-up consists of a test coal shearer and other auxiliary machines is developed for operating long wall coal mining process.Realistic oblique cutting process is developed,and vibration response will be more accurate since both cutting loads and test machine in this experiment are realistic.A data-acquisition system consisting of sensors,channel conditioner and computer is developed to capture three-dimensional vibratory accelerations.A test matrix which included various combinations of key cutting load parameters is executed under realistic oblique cutting loads within a wide parameter range to establish database.Experimental data is analyzed in time,domain and time-frequency domains for investigating the rules of dynamic behavior for SCUG.Beat vibration phenomenon and the coupling of gear mesh frequencies are found in experiment,resulting in local resonance and reduce fatigue life of SCUG.The influence of cutting load on beat phenomenon and frequency coupling is demonstrated at the end,and some conclusions are obtained.
