Embedded Digital Control with Microcontrollers

7Transfer Function Based Control System Analysis

A system has its inherent characteristics. These may not satisfy the required target performance criteria. We can make sure that these are satisfied by adding a controller to the system. Hence, we should first understand what are the possible performance criteria. To do so, we will introduce methods to analyze the system in time domain, frequency domain, and complex plane. These three domains are related. However, they provide valuable information on the same system from different perspectives. We will next explore open- and closed-loop controllers as well as their effects on system performance. Although controller design via transfer functions will be covered in Chapter 8, we believe the system analysis should be understood first. Therefore, we will cover fundamental concepts in control system analysis by transfer functions in this chapter. To be more specific, we will analyze digital systems constructed by open- and closed-loop control methods. We will also provide the corresponding Python functions for analysis methods. We will provide performance analysis of the actual DC motor as the end of chapter application.

7.1 Analyzing System Performance

We can analyze the performance of a system in three domains as time, frequency, and complex plane. We will introduce performance criteria for these in this section. Then, we will analyze the effect of open- and closed-loop controllers in time domain, frequency domain, and complex ...