A Matlab® Approach for Implementing Control Algorithms in Real-Time: RTWT

Abstract

The literature about real-time systems presents digital control or computer controlled systems as one of its most important practical applications. However, it is very difficult to find in these textbooks real-time control aspects (Gambier, 2005). It seems to be more natural that these applications should be treated as part of digital control courses. In spite of that, control system literature rarely includes extensively the real-time subject and it does normally not pay much attention to real-time implementation aspects. Nevertheless, in practice there is the requirement for the design of control algorithms which run in the specified time without detriment to quality and functionality. Thanks to the improvement in some software products, new control algorithms can be designed and tested in real life practical applications very quickly with excellent quality, giving a new optic to the control engineering courses. Software like Matlab/Simulink with its RTW (Real Time Workshop) and the RTWT (Real Time Windows Target) give us the opportunity to work from an easy interface and produce good results, while one deals with time-critical applications. This chapter attempts to give a guide for the implementation of real-time control systems, using the RTWT toolbox, as a practical tool for students in control engineering. A digital PID controller will be tested in a real-life application (Hernandez et al., 2011), in order to present a description of the implementation procedure. The outline of the paper is as follows: a brief introduction to the application problem is depicted in the next section. Definitions and characteristics of real-time systems are described in Section 3. Section 4 treats the implementation of real-time controllers using RTWT in Matlab®. Section 5 is devoted to the configuration of RTWT for our specific application as an example, including some experimental results. Final conclusions are drawn in the last section.