Research on vibration suppression of roadheader rotary table based on active excitation

Due to the randomness of the shape and hardness distribution of coal and rock in the cutting process of the cantilever roadheader, the cutting head will produce irregular violent vibration when cutting into hard rock. The instantaneous high-intensity impact has the greatest impact on the rotary table, which is the key force component of the roadheader. Its dynamic reliability and life affect the cutting efficiency and cutting stability. In order to reduce the vibration of the rotary table in the cutting process, firstly, based on the phenomenon that the rotary table in the cutting site is easy to fail and damage, the mechanical model of the rotary table in the cutting process is established, and the mechanical equation of the rotary table is deduced. The variation law of the force of the rotary table with the cutting parameters is studied. By building a cutting test bench, the vibration response of the rotary table during the cutting process is tested. Combined with the finite element, the vibration modal analysis of the rotary table is carried out to solve the first six natural frequencies and vibration modes of the rotary table, and the reasons for the severe vibration of the rotary table are analyzed. Secondly, based on the theory of working condition path analysis, the transmission path analysis model of cutting process rotary table working condition is established, the synthetic vibration of rotary table is simulated, the contribution and contribution degree of each excitation point to the vibration of rotary table are analyzed, and the main excitation source of rotary table is accurately found. Finally, by applying external active excitation, the vibration of the rotary table under different excitation frequencies is analyzed, and the excitation frequency band that can reduce the vibration of the rotary table during the cutting process is explored. The experimental results show that the external excitation frequency is between 20-60 Hz, and the vibration amplitude of the rotary table is significantly reduced. The excitation frequency of this frequency band has a good effect on the vibration control of the rotary table, which is beneficial to improve the life of the rotary table. When the excitation frequency is 40 Hz, the vibration of the rotary table is the smallest and the vibration suppression effect of the rotary table is the best. The research results are beneficial to enrich the research theory of rotary table vibration, and reduce the force and structural deformation of rotary table without changing the mechanical structure, which can provide theoretical reference for the vibration problem of rotary table of roadheader.