【作者】 周智勇；

【导师】 王福全；

【作者基本信息】 重庆大学 ， 仪器科学与技术， 2022， 硕士

【摘要】 双驱气浮平台是一种精密定位平台,是高精度测量CT系统的主要组成部件之一。双驱气浮平台关键技术主要包括精确运动控制技术和误差补偿技术,其中,直线电机伺服控制系统是保证系统稳定运行的关键,误差补偿可以进一步提升平台定位精度。本文以自主设计的双驱气浮平台为研究对象,主要研究双驱气浮平台的运动控制和误差补偿技术,主要内容如下:(1)通过基本理论研究,建立双驱气浮平台数学模型,设计双驱气浮平台结构。分析系统的关键技术指标。对平台的驱动电机、位置测量系统等关键部件进行选型、加工、装配、调试等。(2)结合实际控制系统的需求,提出一种模糊PID控制算法来改善直线电机的动态响应性能。在Matlab/Simulink上进行PMLSM速度控制仿真,在研制的平台上进行PMLSM速度控制实验。实验结果表明:提出的模糊PID控制方法能够减小系统超调,加快系统响应速度。为进一步提高平台定位精度,在各轴模糊PID控制算法的基础上加入前馈控制,以减小单轴跟踪误差;在两平行轴间设计交叉耦合控制器,减小两平行轴的同步误差。在双驱气浮平台上进行定位实验。实现结果表明:所提控制方法能够提高双驱气浮平台的定位精度。(3)研究各参数变量对平台定位精度的影响。通过改变控制系统参数变量,测量平台定位误差的变化,分析环境变量、控制算法、运动速度、运动加速度和运动步距对定位误差的影响。(4)研究双驱气浮平台定位误差分离与补偿方法,提出一种三次样条插值结合正弦级数和函数拟合的方法对几何误差进行补偿。首先,将双驱气浮平台的定位误差分离成随机误差和几何误差,利用统计学的方法得到修正后的随机误差补偿值,再通过三次样条插值结合正弦级数和函数拟合对几何误差建模,然后对其进行误差补偿。实验结果表明:所提补偿方法可以较大幅度提升双驱气浮平台的双向定位精度和双向重复定位精度。通过该方法,双驱气浮平台的双向定位精度由20.822μm提高到0.247μm,提高了98.81%;双向重复定位精度由0.228μm提高到0.206μm,提高了9.65%,满足双驱气浮平台的技术指标。更多还原

【Abstract】 The double-drive air bearing stage is a precision positioning stage and one of the main components of a high-precision measurement CT system.The key technologies of the double-drive air bearing stage mainly include precise motion control technology and error compensation technology.Among them,the linear motor servo control system is the key to ensure the stable operation of the system,and error compensation can further improve the positioning accuracy of the stage.This thesis takes the self-designed double-drive air bearing stage as the research object,and mainly studies the motion control and error compensation of the double-drive air bearing stage.The main contents are as follows:(1)Through basic theoretical research,the mathematical model of the double-drive air bearing stage is established,and the structure of the double-drive air bearing stage is designed.The key technical indicators of the system are analyzed.The key components such as the drive motor and position measurement system of the stage are selected,processed,assembled,and debugged.(2)Combined with the requirements of the actual control system,a fuzzy PID control algorithm is proposed to improve the dynamic response performance of the linear motor.The PMLSM speed control simulation is carried out on Matlab/Simulink,and the PMLSM speed control experiment is carried out on the developed stage.The experimental results show that the proposed fuzzy PID control method can reduce the system overshoot and speed up the system response.In order to further improve the positioning accuracy of the stage,feedforward control is added on the basis of the fuzzy PID control algorithm of each axis to reduce the single-axis tracking error;a cross-coupled controller is designed to reduce the synchronization error of the two parallel axes.The positioning experiment is carried out on the double-drive air bearing stage.The implementation results show that the proposed control method can improve the positioning accuracy of the double-drive air bearing stage.(3)The influence of each parameter variable on the positioning accuracy of the stage is studied.By changing the parameter variables of the control system,the changes in the positioning error of the stage are measured,and the effects of environmental variables,control algorithms,movement speed,movement acceleration and movement step distance on the positioning error are analyzed.(4)The method of separating and compensating the positioning error of the double-drive air bearing stage is studied,and a method of cubic spline interpolation combined with sum function of sine series is proposed to compensate the geometric error.First,the positioning error of the double-drive air bearing stage is separated into random errors and geometric errors,and the corrected random error compensation value is obtained by statistical methods,and then the positioning error is compensated.The experimental results show that the proposed compensation method can greatly improve the bidirectional accuracy of positioning and bidirectional repeatability of positioning of the double-drive air bearing stage.Through this method,the bidirectional accuracy of positioning of the double-drive air bearing stage is increased from 20.822μm to0.247μm,an increase of 98.81%;the bidirectional repeatability of positioning is increased from 0.228μm to 0.206μm,an increase of 9.65%,which meets the technical indicators of the double-drive air bearing stage.更多还原