Wordlength and Sampling Rate Considerations in the Implementation of Digital Controllers
Williamson · 1986
The performance of continuous time controllers can be matched by a digital controller operating under a fast sampling rate. However, this can lead to severe numerical ill conditioning in the implementation of the algorithm unless a suitable structure is chosen. In this paper we show how the ideas of scaling originally developed for analogue computer simulations can be used to advantage in the digital design. Emphasis is placed on a particular structure requiring only 3N multiplications per sample period where N is the number of controller poles. Scaling which is designed to achieve low dynamic range in controller parameters also achieves good scaling with respect to the controller states.