An analysis and performance assessment of double EWMA control systems

Run-to-run (RtR) control technology has received tremendous interest in semiconductor manufacturing industry. Exponentially weighted moving average (EWMA), double EWMA controllers are recognized most popular control schemes for RtR control. In this paper, stability analysis of double EWMA control system is examined in control theory. The novelty of this work is that an iterative method is developed to obtain the best achievable performance of the double EWMA control system. The performance of double EWMA control system is evaluated and the discount factors are retuned. Simulation example is given to show the effectiveness of the proposed method.