Frequency response analysis of microcontroller-based discrete-time lead-lag compensators

摘要

With the rapid advancement of digital processors, filters have been commonlyimplemented using microcomputers. In this study, a low-cost and compact Arduino Unodevelopment board was used to realize digital lead and lag compensators. Arduino boardsare very affordable. Consequently, they were investigated to see if they were capable ofpreserving the frequency response of continuous-time compensators. The experimentsrequired a set of equipment including a function generator, an Arduino Uno developmentboard, a PC-based oscilloscope, and a laptop. The signal frequency was varied from 0to 500 Hz. Two discretization methods were employed, namely bilinear transformationand matched pole-zero mapping. The results showed that an Arduino Uno board canbe utilized to implement lead and lag compensators to some extent. The discrete-timecompensator preserved the capability of filtering out certain frequencies. The change in DCgain was negligible, however, there was a significant difference in the cut-off frequency andtransient slope. For both discretization methods, the frequency responses at high frequencyexperienced a rippling profile.