Motion systems with multiple control loops often run at a single sampling rate for simplicity of implementation and controller design. The achievable performance in terms of position accuracy is determined by the data acquisition hardware, such as sensors, actuators, and analog-to-digital/digital-to-analog converters, which is typically limited due to economic cost considerations. The aim of this paper is to develop a multirate approach to go beyond this traditional performance/cost tradeoff, i.e., to use different sampling rates in different control loops to optimally use hardware resources. The approach appropriately deals with the inherent time-varying behavior that is introduced by multirate sampling. A multirate feedforward control design framework is presented to optimize the tracking of a dual-stage multirate system. The application of the proposed approach to an industrial dual-stage wafer system demonstrates the advantages of multirate control, both in simulations and experiments.

中文翻译：

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运动控制中超越性能/成本的权衡：应用于双阶段晶圆系统的多速率前馈设计

为了简化实现和控制器设计，具有多个控制回路的运动系统通常以单个采样率运行。就位置精度而言，可实现的性能由数据采集硬件（例如传感器，执行器和模数/数模转换器）确定，这些性能通常由于经济成本方面的考虑而受到限制。本文的目的是开发一种超越传统性能/成本折衷的多速率方法，即在不同的控制环路中使用不同的采样率来最佳地利用硬件资源。该方法适当地处理了由多速率采样引入的固有时变行为。提出了一种多速率前馈控制设计框架，以优化对双级多速率系统的跟踪。