基于主动激励的掘进机回转台振动抑制研究

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

悬臂式掘进机截割过程由于煤岩形状、硬度分布的随机性,当截割到硬岩时截割头会产生无规则的剧烈振动,瞬时高强度的冲击对掘进机关键受力部件回转台影响最大,其动态可靠性和寿命影响着截割效率和截割稳定性,为减弱截割过程回转台的振动,首先,基于截割现场回转台易失效损坏现象,建立截割过程回转台力学模型,推导回转台力学方程,研究回转台受力随截割参数变化规律;通过搭建截割试验台,测试截割过程回转台振动响应,结合有限元进行回转台振动模态分析,求解回转台前6阶固有频率及振型,分析回转台剧烈振动的原因。其次,基于工况路径分析理论,建立截割过程回转台工况传递路径分析模型,模拟回转台合成振动,分析各激励点对回转台振动贡献量及贡献程度,准确找到回转台主要激振源。最后,通过施加外部主动激励的方式,分析不同激励频率加载下回转台振动情况,探寻能够降低截割过程回转台振动的激励频段。试验结果表明:外部激振频率处于20~60 Hz,回转台振动幅值降低明显,此频段激励频率对回转台振动控制效果良好,有益于提高回转台寿命,且激振频率为40 Hz时回转台振动最小,回转台振动抑制效果最佳。研究结果有益于丰富回转台振动相关研究理论,实现在不改变机械结构基础上,降低回转台受力与结构变形,可为掘进机回转台的振动问题提供理论参考。

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.