Abstract:

This paper aims to obtain adaptive controllers capable of interacting and controlling a physical system in real time. This task is accomplished using a model with a DC motor platform in order to carry out test and to obtain experimental results. It could then be possible to extend these controllers to other systems with minor changes. To achieve this purpose, MATLAB and Simulink simulation environment are used, creating the models needed through block languages.

In general, control by using conventional regulators is the more common practice (Unizar, 2013), but they have certain limitations (Balzasbravas, 2013), for example, the system identification and the calculation of the controller parameters have to be calculated offline (D. Rodriguez, 2005), so that the nonlinearities in the system can cause instabilities in the response. An advantage of the adaptive control is that it works online but requires a more complex design.

Matlab’s Simulink (Matlab, 2012), provides a powerful tool and incorporates the Real-Time Windows Target module that allows real-time control, with the possibility of exporting the models to another programming language such as C language that it is commonly used in the industry. In the implementation of adaptive controllers comes the difficult problem of managing the real-time discrete states when working in External Mode because it is a complex task. From the 2012 version of MATLAB, a series of facilities make this work more feasible to perform.

The operation of adaptive regulators is composed by four basic steps. The first is ‘to begin with a conventional control" that only takes place in the first moments of time and involves the performance of a conventional control while the identification block obtains a first estimate of the system and from there it begins an iterative process where involves the following three steps: identification of the system by some method such as minimum square with a forgetting factor (Uba, 2010), calculation of the controller parameters and adaptive control of the system with the calculated parameters. While it is true that these steps are more focused on STR drivers (A. Aguado, 2002), it is difficult to make them extensible to other types (Morfe, 2013).

Keywords:

Adaptive control, Control lab, Hardware control.