Cascaded filter PID paradigm for error-based active disturbance rejection control: equivalence, design, and implementation guidelines

Aiming to implement an “advanced” control concept in a form familiar to industrial practitioners, this article proposes a cascaded filter PID paradigm for error-based active disturbance rejection control (eADRC). The proposed paradigm reveals that a PID controller can be transformed into an equivalent eADRC scheme by cascading a filter and then selecting the parameters of the filter and controller according to the derived rules. Such a transformation procedure can easily inject the beneficial characteristics of eADRC into an existing PID-type scheme while fully retaining and utilizing the original algorithm. Although some results on the seamless connection between those two control schemes have recently emerged, their analyses are limited to low-order systems. This article extends the discussion to general cases. Different implementation forms of eADRC are summarized, and comprehensive guidelines for controller design are provided. Moreover, the proposed paradigm and implementation guidelines are applied to position control of a permanent magnet synchronous motor system. A brief theoretical analysis and sufficient hardware experiments verify the effectiveness of the proposed methodology.