基于电磁激励的滑动轴承轴心轨迹主动控制研究

发布时间：2018-01-25 12:02

  本文关键词： 滑动轴承 轴心轨迹控制 混合灵敏度 回路成形 半实物仿真　出处：《山东大学》2011年硕士论文　论文类型：学位论文

【摘要】：非圆异形截面结构能够显著提高零件的性能和使用寿命,但由于非圆异形截面结构的特殊性,给此类零件的加工提出了难题。本文以基于电磁激励的滑动轴承系统的主轴运动轨迹控制为出发点,研究了转子运动轨迹的主动控制技术,以期为非圆异形截面零件的加工提供一种新方法。综合分析了传统的以及最新发展的各种加工非圆异形截面零件的方法以及伺服驱动装置,提出了基于电磁激励控制的滑动轴承中心轨迹的方法,来实现主轴按照预定非圆轨迹运动。实现思路是油膜力作为主要支撑力,电磁力作为控制力,通过伺服控制技术实时控制励磁电流,从而控制电磁铁与转子之间的作用力,从而达到控制转子运动轨迹的目的。 对轴承系统进行了理论研究,建立了滑动轴承倾转主轴的运动模型和动力学模型,推导了主轴发生倾转时的油膜压力分布Reynolds方程,推导了油膜厚度方程。用差分法对油膜压力分布进行了计算,用辛普森积分法对油膜力矩进行了求解。推导了电磁力矩的表达式,用运动学方法对转子轴心轨迹进行了计算。基于轴承的局部线性化的模型建立了扰动压力Reynolds方程,对轴承系统八个特性系数进行了理论分析计算。研究了转速和励磁电流对特性系数的影响,建立了被控对象的无量纲动力学模型,对控制方案进行了分析。 研究了滑动轴承系统基于鲁棒Hoo的控制方法,被控对象可观可控,可以通过状态反馈实现输入输出解耦。基于全局寻优的遗传算法设计鲁棒H∞混合灵敏度控制器,该控制器实现被控对象输出对参考信号的良好跟踪,并对外界扰动有一定的抑制作用,但由于解耦矩阵对模型摄动比较敏感,仅能容许模型小幅摄动。基于鲁棒H∞回路成形方法直接对耦合系统设计控制器,实现输入输出解耦,对控制器进行降阶处理,该控制器对模型摄动和外界扰动均有较好的抑制作用,满足鲁棒性能和鲁棒稳定性要求。 对滑动轴承转子轨迹控制实验进行了设计,提出基于xPC Target的硬件在回路的控制仿真实验方法。搭建了xPC Target仿真平台,对xPC Target平台进行了通信和信号输入输出测试,对电容式位移传感器进行了标定,由于时间和实验条件有限,未完成硬件在回路仿真实验。
[Abstract]:Non-circular special-section structure can significantly improve the performance and service life of the parts, but due to the particularity of non-circular special-shaped cross-section structure. In this paper, the active control technology of rotor motion trajectory is studied based on the spindle motion trajectory control of the sliding bearing system based on electromagnetic excitation. In order to provide a new method for the machining of non-circular special-section parts, this paper synthetically analyzes the traditional and newly developed methods of machining non-circular special-section parts and the servo drive device. A method based on electromagnetic excitation control is proposed to realize the spindle moving according to the predetermined non-circular trajectory. The realization idea is that the oil film force is the main supporting force and the electromagnetic force is the control force. The excitation current is real-time controlled by servo control technology to control the force between the electromagnet and the rotor, so as to control the track of the rotor motion. This paper studies the bearing system theoretically, establishes the motion model and dynamic model of sliding bearing tilting spindle, and deduces the Reynolds equation of oil film pressure distribution when the spindle tilts. The oil film thickness equation is derived, the oil film pressure distribution is calculated by difference method, the oil film torque is solved by Simpson integral method, and the expression of electromagnetic torque is derived. The rotor axis trajectory is calculated by kinematics method, and the Reynolds equation of disturbance pressure is established based on the local linearization model of the bearing. Eight characteristic coefficients of bearing system are theoretically analyzed and calculated. The effects of rotational speed and excitation current on the characteristic coefficients are studied. The dimensionless dynamic model of the controlled object is established and the control scheme is analyzed. The control method of sliding bearing system based on robust Hoo is studied. The controlled object is observable and controllable. The robust H 鈭，

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