| With the development of coal mining to deep coal seam,the high occurrence rate,strong contingency,high casualty rate of geological hazards in deep seam,such as gas explosion,rock collapse,water inrush,which raises a high demand for the reliability,unmanned and adaptability of the drum shearer.The drum shearer is one of the major parts of the fully mechanized coal mining outfit equipment,and plays a decisive role in improving the cutting efficiency of the fully mechanized coal face.A coal seam is always non-homogeneous with hard parcels and rock intercalation,and causes various concerns,including strong impact,heavy loads,and large fluctuations to the drum,which lead to the frequent failures of the cutting transmission system.Aiming at different steady state cutting conditions,when the traction speed changes in a larger range,it is difficult to ensure the drum shearer in the best working state with strong cutting ability,low cutting energy consumption and high lump coal rate.Therefore,the power transmission system of unmanned drum shearer needs to have a high dynamic adaptive ability to working conditions,on the basis of ensuring the reliable operation of the transmission system,to achieve the efficient production of the drum shearer.According to the 4th task of The National Major Basic Research Program of China(973 Program,Grant No.2014CB046304),taking an electric haulage drum shearer as the research object,the research on adaptive control for power transmission system of drum shearer under complex cutting conditions is carried out,to realize the safe operation and high efficiency production of the drum shearer under different conditions.The specific research work is as follows:(1)Considering the time-varying meshing stiffness,dynamic characteristics of the motor as well as drum load characteristic,an electro-mechanical coupling model of the cutting unit,an electro-mechanical coupling model of the traction unit,and a control system model of drive motor are respectively built firstly,then a coupling dynamics model of drum shearer including cutting unit and traction unit as well as control system is built based on the coupling transfer relation of drum loads.(2)Effect of impact loads on electromechanical dynamic characteristics of drum shearer cutting transmission system is conducted,suppression effect of control characteristics of cutting motor on the dynamic loads impact energy of different meshing pairs in cutting transmission system is analyzed,as well as effect of electromagnetic torque ripple of cutting motor on the system dynamic loads impact energy is analyzed.In addition,aimming at the different steady state cutting conditions,effect of drum variable speed cutting on comprehensive performance of coal mining is conducted,including the effect of drum motion parameters on dynamic characteristics of drum shearer cutting transmission system,coal mining productivity,lump coal rate,as well as cutting specific energy consumption.Above all of these lay the foundation for the adaptive control for dynamic loads suppressin of cutting transmission system under impact conditions and cutting-traction speed control for the optimal comprehensive performance of coal mining under different steady state cutting conditions.(3)Amming at the impact conditions,an adaptive control method for dynamic loads suppression based on the active disturbance rejection torque compensation is proposed,which uses the speed difference of elastic axis as a feedback signal.The speed difference is set to be zero as the given tracking target,and transforms the gear dynamic loads suppression problem into the trajectory tracking problem.Then,on basis of the given electromagnetic torque from the DTC controller,the additional compensation torque for dynamic load suppression is superposed.Thus,dynamic loads impact energy can be suppressed by controlling the electromagnetic torque of cutting motor.Wha's more,the parameters of active disturbance rejection controller can be tuned based on the adaptive neuro-fuzzy control technology,and the expert control rules for complex cutting conditions are obtained,which realizes the effective suppression for the dynamic loads impact energy of the cutting transmission system.(4)Aimming at the different steady state cutting conditions,using the traction speed and cutting speed as the design variable,using dynamic loads of gears,coal mining productivity,lump coal percentage as well as cutting energy consumption as the sub-goals,a multi-objective optimization model of comprehensive cutting performance is established.Then,an optimization method for weight coefficients selection of the different cutting performance is proposed based on the weight coefficients transformation,to determine the optimum weight combination for different conditions.Finally,the optimization calculation is conducted based on genetic optimization algorithm,the optimal motion parameters with the change of cutting resistance are obtained under normal coal seam,gangue coal seam and rock fault condition,which realizes the cutting-traction speed control for the optimal comprehensive performance of coal mining under different cutting conditions.On this basis,combining the adaptive control method for dynamic loads suppression under impact conditions,the adaptive control of power transmission system of drum shearer under complex cutting conditions is realized,to ensure the safe operation and high efficiency production of drum shearer.(5)A high dynamic performance test bench for power transmission system of drum shearer is designed and built.In addition,a data acquisition system and a measurement and control system are developed based on dSPACE and QuantumX platform.Then,experimental research on dynamic characteristics of power transmission system of drum shearer under variable loads and variable speed conditions is carried out.What's more,experimental research on the adaptive control method for system dynamic loads impact erengy suppression.Thus,the relevant theoretical results obtained in this paper are verified. |
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