基于方箱的气浮工作台控制系统稳定性分析

The stability analysis of control system of aerostatic worktable based on square box

  • 摘要: 为了进一步开展对气浮静压导轨支承与直线电机驱动相互匹配稳定性研究,设计并研制了一种基于方箱的二维气浮工作台。二维气浮工作台以方箱为机构设计和装配基准可以有效提高其承载性能和运动精度,但由于整个气浮工作台摩擦阻尼小、负载惯性大而导致其控制系统稳定性较差,因而需对其系统的稳定性进行分析并提出其改进措施。论文基于气浮工作台建立了其直线电机数学模型并推导了其控制系统传递函数,采用Matlab对其伯德图进行计算和稳定性裕度分析并搭建了实验平台进行验证。结果表明:气浮工作台两轴向的电流环、速度环以及位置环的相角裕度均大于60°以及幅值裕度大于10 dB,满足系统稳定裕度要求从而保证了控制系统具有良好的稳定性;实验结果与仿真分析结果具有较好的一致性,验证了气浮工作台控制系统的稳定性。

     

    Abstract: In order to further study the matching stability of aerostatic guide rail support and linear motor drive, a two-dimensional aerostatic worktable based on square box was designed and developed. Taking square box as the mechanism design and assembly reference could effectively improve the bearing performance and motion accuracy of the two-dimensional aerostatic worktable. However, the stability of the control system of the whole aerostatic worktable was difference, due to the small friction damping and large load inertia. Therefore, the stability of the system needed to be analyzed and the improvement measures were proposed. In this essay, the mathematical model of the linear motor was established based on the aerostatic worktable, and the transfer function of the control system was derived. The Bode diagram was calculated and the stability margin was analyzed by Matlab, and an experimental platform was built for verification. The results showed that the phase margin of the current loop, the velocity loop and the position loop in the two axial directions of the aerostatic worktable were greater than 60° and the amplitude margin was greater than 10 dB, which met the requirements of the system stability margin and ensured the good stability of the control system. The experimental results were in good agreement with the simulation results, which verifies the stability of the control system of the aerostatic worktable.

     

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