长行程精密直线运动平台的滑模控制研究

发布时间：2018-11-13 17:26

【摘要】：光刻机系统中涉及大量的运动部件,它们的形式、指标各不相同,通过协调完成换台、步进、扫描等复杂运动,但其本质都属于运动平台。由于系统对运动控制极高的性能要求,有必要专门针对运动平台展开研究,因此本文选取了光刻机系统中具有典型代表性的长行程精密直线运动平台展开研究。为了抑制平台上存在的各种干扰,本文将滑模控制应用到平台上,经过仿真和试验验证了控制器的有效性,使系统跟踪精度和快速性得到了提高。首先,对运动平台的工作特点以及各部分结构、性能指标进行介绍,并针对平台的运动特点规划了S曲线,作为参考轨迹。通过对平台上的干扰进行分析,指出平台上存在非线性扰动、参数摄动、模型不确定性以及机械谐振等不利于控制的情况。最后通过扫频实验获取了平台的频域响应,并利用二阶传递函数拟合,从而获得平台的传递函数。其次,为了克服平台上的各种不利条件,提升系统性能,在扫频获得的传递函数基础上,提出了一种利用改进型粒子群算法进行参数优化的滑模控制方法。该方法采用线性滑模面,通过边界层方法对滑模项加以改进,以达到抑制抖振的目的。最后在仿真时表现出了比PID控制方法更强的干扰抑制能力,并取得了更好跟踪精度和快速性。再次,上述滑模算法虽然相对传统的PID算法性能有提升,但是存在:快速性有待提高,抖振问题较为严重的问题,因此有必要对算法进行改进。为了提高快速性,将之前的滑模面换成了终端型滑模面,提升了状态到达滑模面上的速度,并且提高了精度。为了抑制抖振,摒弃了之前的边界层法,而选择了二阶滑模。这种控制方法在不降低滑模抗扰动能力的情况下大幅抑制了抖振,而且跟踪精度进一步提升。通过将三种滑模控制方法进行仿真对比,结果表明了二阶非奇异快速终端算法的优越性。最后,对运动平台控制系统的各个环节进行介绍,将所上述各种控制方法在硬件平台上实现,控制运动平台进行实验。从跟踪精度、快速性、抖振情况三个方面对各个控制算法进行对比,证明了二阶非奇异快速终端滑模的优越性,使系统性能得到了提升。
[Abstract]:A large number of moving parts are involved in the lithography system, their forms and indexes are different, and the complex motion such as changing, stepping, scanning and so on are completed through coordination, but their essence belongs to the motion platform. Due to the high performance requirement of motion control, it is necessary to study the motion platform. Therefore, this paper selects the typical long-stroke precision linear motion platform in the lithography system to carry out the research. In order to suppress all kinds of interference on the platform, the sliding mode control is applied to the platform in this paper. The effectiveness of the controller is verified by simulation and experiment, and the tracking accuracy and rapidity of the system are improved. Firstly, the working characteristics, the structure and the performance index of the platform are introduced, and the S curve is designed as the reference track according to the motion characteristics of the platform. By analyzing the disturbance on the platform, it is pointed out that the nonlinear disturbance, parameter perturbation, model uncertainty and mechanical resonance are not conducive to the control of the platform. Finally, the frequency domain response of the platform is obtained by the sweep experiment, and the second order transfer function is used to fit the platform transfer function. Secondly, in order to overcome the disadvantages of the platform and improve the performance of the system, a sliding mode control method using improved particle swarm optimization (PSO) is proposed on the basis of the transfer function obtained by sweep frequency. The linear sliding mode surface is used to improve the sliding mode term through the boundary layer method in order to suppress buffeting. Finally, the simulation results show that the interference suppression ability is stronger than the PID control method, and better tracking accuracy and rapidity are obtained. Thirdly, although the performance of the sliding mode algorithm is improved compared with the traditional PID algorithm, there are some problems, such as the need to improve the rapidity and the more serious buffeting problem, so it is necessary to improve the algorithm. In order to improve the rapidity, the former sliding mode surface is replaced by the terminal sliding mode surface, which improves the speed of the state reaching the sliding mode surface and improves the accuracy. In order to suppress buffeting, the boundary layer method is abandoned and the second-order sliding mode is chosen. This control method can greatly suppress the chattering and improve the tracking accuracy without reducing the anti-disturbance ability of the sliding mode. The simulation results of three sliding mode control methods show the superiority of the second order nonsingular fast terminal algorithm. Finally, every link of the motion platform control system is introduced, the above control methods are realized on the hardware platform, and the motion platform is controlled for experiment. The control algorithms are compared in terms of tracking accuracy, rapidity and buffeting. The advantages of the sliding mode of the second order nonsingular fast terminal are proved, and the performance of the system is improved.
【学位授予单位】：哈尔滨工业大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TP273;TN405

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