关键词：控制器；统计过程
摘 要：Indeed, understanding this variation may be a first step towards the improvement of controller performance. Since variation is present in any process, deciding when the variation is natural and when it needs correction is the key to monitor control performance using SPC. In this context, it should be stressed that SPC is a monitoring rather than control technique because no automatic corrective action is taken after an abnormal process situation is detected. SPC can be traced back to Walter Shewhart, who introduced the use of SPC control charts in the 1920s for adapting management processes to create profitable situations for both businesses and consumers. Today, SPC has become more than control charting alone; it is an umbrella term for the set of activities and methods for data analysis and quality control. This chapter contains a brief description of selected SPC techniques: Sect. 8.1 presents some control charts typically used in univariate SPC; multivariate SPC methods are given in Sect. 8.2.