The integral sliding mode control of a pneumatic force servo for the polishing process
The integral sliding mode control of a pneumatic force servo for the polishing process
复制标题
抛光过程气动力伺服系统的积分滑模控制
DOI：
10.1016/j.precisioneng.2018.09.001
复制
发表时间：
2019-01-01
影响因子：
3.6
通讯作者：
Sun, Lining
中科院分区：
文献类型：
--
作者：
Fan, Cheng;Hong, Geok Soon;Sun, Lining
抛光过程的自动化是提高生产效率和零件表面质量的关键。控制策略是自动抛光过程的一大瓶颈，涉及到位置/力的控制。本文主要研究抛光过程中气动力的精确控制。首先，描述了一种位置/力解耦抛光系统，该系统由刀具轨迹控制子系统和基于气动力伺服的抛光力控制子系统组成。然后，以伪随机二进制序列(PRBS)信号作为输入，通过估计系统输出来辨识气动力伺服系统的动态模型。基于该动态输入输出模型，针对辨识出的非最小相位系统，设计了一种由等效控制和切换控制组成的新型积分滑模控制器。力控制实验表明，该控制器能有效地抑制主轴旋转的外部扰动和由于气动系统的非线性特性引起的模型不确定性，且抛光力的控制精度比传统的PID控制器和RST控制器有所提高。最后，对材料去除均匀的球面进行了抛光实验，抛光结果表明，抛光后表面粗糙度由135.8 nm提高到14.7 nm。这种新的积分滑模控制方法是有效的，在进一步的工业抛光力控制中具有很大的应用潜力。
The automation of the polishing process is essential to improve the production efficiency and the quality of the part surfaces. The control strategy, which involves the position/force control, is a big bottleneck for the automated polishing process. This paper focuses on the precise control of the pneumatic force in polishing. Firstly, a position/force decoupled polishing system is described, which consists of a tool-path control subsystem and a polishing force control subsystem based on a pneumatic force servo. Then, the dynamic model of the pneumatic force servo is identified by evaluating the system output while the input is provided by the Pseudo Random Binary Sequence (PRBS) signals. Based on this dynamic input-output model, a new integral sliding mode controller (ISMC), which is composed by equivalent control and switching control, is especially designed for the non-minimum phase system identified. The force control experiments show that the proposed controller is effective in suppressing the external disturbance of spindle rotation and model uncertainties due to the nonlinear characteristics of the pneumatic system; and the control accuracy of the polishing force is improved compared to the traditional PID controller and RST controller. Finally, the polishing experiment of a spherical surface with uniform material removal has been conducted and the polishing results show that the surface roughness greatly improved from 135.8 nm to 14.7 nm. This new integral sliding model control method is effective and has great potential application in the further industrial polishing force control.