一种机器人铣削颤振抑制用磁流变弹性体吸振器的设计与试验研究

Design and experimental study of a magnetorheological elastomer vibration absorber for chatter suppression in robotic milling

  • 摘要: 为了解决工业机器人铣削加工过程中的低频颤振问题,设计了一种用于抑制振动的磁流变弹性体(magnetorheological elastomer,MRE)吸振器。利用MRE特有的流变特性,研究了不同质量配比的MRE磁流变效应,通过理论计算和数值仿真确定了吸振器内部的线圈匝数及所通电流大小。通过模态仿真和振动台扫频激励试验发现,设计的MRE吸振器具有17.35~45.21 Hz范围内的移频特性。建立了吸振器固有频率‑电流映射关系,在KUKA KR500机器人铣削加工过程中进行了试验验证。结果表明,在低转速加工条件下机器人容易在其低阶固有频率处发生颤振,通过MRE吸振器实现了颤振抑制。相对于不加吸振器的工况,通电调频后机器人主轴X方向上的振动加速度峰峰值降低了70.7%,均方根值降低了64.7%;Y方向峰峰值降低了54.7%,均方根值降低了49.9%。此外,铣削工件的表面加工质量也有明显改善。

     

    Abstract: A magnetorheological elastomer (MRE) vibration absorber is designed to suppress the vibration of industrial robotic milling in order to solve the low frequency chatter problem. The magnetorheological effect of MRE with different mass ratio is studied by using the unique rheological characteristics of MRE. The number of turns of coil and the current in the absorber are determined by theoretical calculation and numerical simulation. It is found that the designed MRE absorber has frequency shift characteristics in the range of 17.35~45.21 Hz through modal simulation and shaking table sweeping excitation experiment. The mapping relationship between natural frequency of absorber and current is established, which is verified by experiments in the milling process of KUKA KR500 robot. The results show that the robot is prone to chatter at its low order natural frequency under low rotational speed machining conditions, and the chatter suppression of the robot is realized by MRE absorber. Compared with the condition without vibration absorber, the peak-to-peak value of the vibration acceleration in the X direction of the robot spindle is reduced by 70.7%, and the root-mean-square value is reduced by 64.7% after being electrified. The peak-to-peak value in the Y direction is decreased by 54.7%, and the root-mean-square value is decreased by 49.9%. In addition, the machining surface quality of workpieces after milling has also been significantly improved.

     

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