This note addresses the high-speed, high-precision point-to-point motion control of an air-bearing planar stage. The custom-designed stage uses four air-bearings to levitate the stage for the high-speed frictionless operation. Because of the floating nature, the controller for the system needs to overcome the nonlinear free-moving dynamics of the stage and achieve the required performance. To fulfill this purpose, we propose a unique integrated control structure that allows both velocity and reference position inputs. With the proposed structure and the weighting design, it is possible to use the $H_{\infty }$ chain scattering description ($H_{\infty }$-CSD) synthesis for the control parameters. The single structure is used for both the point-to-point movement and the high precision positioning. The reference velocity input enables the long-stroke time-optimal velocity profile injection. The controller converges to the popular PDF control when the stage comes close to the target position. The $H_{\infty }$ specifications enable a robust performance against the load uncertainty. The control undergoes no switching and is thus free from the undesirable chattering. The experimental results show that the proposed control achieves an ultrahigh precision control of 20 nm within 200 ms for a 9-kg stage with 20-mm x, y motion ranges.

本说明介绍了带空气平面平台的高速，高精度点对点运动控制。定制设计的载物台使用四个空气轴承使载物台悬浮以实现高速无摩擦操作。由于具有浮动特性，因此系统的控制器需要克服平台的非线性自由移动动力学并实现所需的性能。为了实现此目的，我们提出了一种独特的集成控制结构，该结构允许同时输入速度和参考位置。通过建议的结构和权重设计，可以使用$H_{\infty }$ 链散射描述（$H_{\infty }$-CSD）综合控制参数。单一结构可用于点对点移动和高精度定位。参考速度输入可实现长冲程时间最佳速度曲线注入。当载物台接近目标位置时，控制器会收敛到流行的PDF控件。的$H_{\infty }$规格可提供强大的性能以应对负载不确定性。控制器不进行任何切换，因此不会产生不希望的抖动。实验结果表明，对于具有20mm x，y运动范围的9kg载物台，拟议的控制在200ms内实现了20nm的超高精度控制。