基于重复控制的静压轴承-主轴系统非圆轴心轨迹成型技术研究

Research on Non-circular Journal Orbit Forming Technology of Hydrostatic Bearing-spindle System Based on Repetitive Control

非圆轴心轨迹成型技术可用于异形曲面加工等特殊用途。为提高非圆轴心轨迹的成型精度,提出了可控静压轴承主轴系统的重复控制方法。可控静压轴承主轴系统是一个多变量耦合系统,模型复杂。为了便于控制器的设计,对系统原有线性参变模型进行了简化,建立了线性解耦模型。根据非圆轴心轨迹成型的特点,将重复控制器引入原PI控制系统,并根据稳定性准则,设计了重复控制器各参数,同时,为保证系统对非圆轨迹的跟踪精度,分析了增益参数对系统稳定性和性能之间的影响。最后建立了可控静压轴承主轴仿真与实验系统,并将重复控制与传统PI控制策略进行了对比。结果表明,该重复控制系统具有较强的鲁棒性且稳态误差更小,控制精度相较于PI控制系统有显著的提升。

The non-circular journal orbit forming technology can be used for special applications such as shaped surface processing.In order to improve the forming accuracy of non-circular journal orbit,a repetitive control method of controllable hydrostatic bearing spindle system is proposed.The controllable hydrostatic bearing spindle system is a multivariable coupled system with a complex model.In order to facilitate the design of the controller,the original linear parametric model of the system is simplified and a linear decoupling model is established.According to the characteristics of non-circular journal orbit forming,the repetitive controller is introduced into the original PI control system,and each parameter of the repetitive controller is designed according to the stability criterion.Meanwhile,to ensure the tracking accuracy of the system for non-circular trajectory,the influence between the gain parameters on the stability and performance of the system is analyzed.Finally,a controlled hydrostatic bearing spindle simulation and experiment system is established,and the repetitive control is compared with the traditional PI control strategy.The results show that the repetitive control system has stronger robustness and smaller steady-state error,meanwhile,the control accuracy is significantly improved compared with the PI control system.