Analysis Of The Vibration Characteristics Of Roadheader In Cutting Process

The maladjustment of coal mining and roadway driving is increasingly evident in the current coal production.It is of great significance to improve the working efficiency of roadheader and reduce the system failure rate to alleviate the imbalance between coal mining and roadway driving.The vibration impact caused by the coal wall breaking of the roadheader will not only accelerate the wear and tear of the parts of the roadheader and reduce the service life,but also easily cause the failure of the electrical control system and hydraulic drive system arranged on the fuselage and increase the maintenance period.Therefore,the study of vibration characteristics of roadheader has a positive effect on improving mechanical performance and reducing failure rate.This paper takes longitudinal-axial cantilever roadheader as the research object.By Adopting the method of combining theoretical modeling and numerical simulation.the vibration characteristics of roadheader under different working conditions and its response law under the action of system parameters are studied.The main contents are as follows:（1）Based on the analysis of pick load and its position distribution on the cutting head,the calculation formula of cutting head load is established;Through the analysis of the running resistance of the crawler walking mechanism,the calculation formula of the output driving force of the crawler walking mechanism is obtained;Establishing the cutting arm-continuum model and obtaining the main mode function and the dynamic response of.the cutting arm.（2）The theory of multibody dynamics is adopted.On the basis of the cutting head load and driving force calculation formula of crawler walking mechanism established,considering the flexible deformation of cutting arm in vibration,based on the Hamiltonian principle,the dynamic model of roadheader under vertical and rotary cutting conditions is established.The multi-scale method is used to solve the dynamic equation and the resonance characteristic equation of the system is obtained.（3）Based on the established dynamic model of vertical direct cutting and rotary cutting of roadheader,the dynamic response of system vibration and the vibration distribution of the cutting arm were obtained by numerical solution of Matlab software.The results show that the displacement vibration range of the body of the roadheader in the vertical direction is±4.1mm.The displacement vibration range of the turning mechanism of the roadheader in the vertical direction is±6.8mm.The displacement vibration range of the body in the driving direction is±4.7mm.The vibration range of the end of the cutting arm in the vertical cutting condition is the largest,and the displacement vibration range is±27.8mm;The rotation hydraulic pressure in the rotary cutting condition is±27.8mm.The displacement vibration range of the cylinder is±2.4mm.The vibration range of the rotary foundation is±3.9×10^-3rad,and the vibration range of the end of the cutting arm is±22.4mm.（4）The system resonance characteristic equation was obtained based on the multi-scale method,and the influence law of system internal parameters on the system vibration amplitude was analyzed by Matlab software.The influence of stiffness,damping and load excitation on the system resonance is obtained by comparing the amplitude response under different values of a single parameter.The results show that the damage of resonance to the system can be reduced by increasing the connection stiffness,increasing the system damping and controlling the driving parameters reasonably to reduce the load excitation amplitude.