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Design of Fractional Order Fuzzy Sliding Mode Controller Chapter | 9 265

9.6 OPTIMIZATION OF CONTROLLER GAINS BY GA
Tuning of the controller parameter plays a vital role in the perfect design of
controllers like SMC. A properly tuned controller tries to minimize the
objective function of overall system and it assures the process output to track
the desired trajectory as well as to reduce the effect of disturbances coming
to the system. To tune a variable order controller like SMC, there is not any
method that has been specified in the literature survey. In the present work,
GA is used to tune the controller parameters.

9.6.1 Description of GA
The idea of GA was developed by John Holland and his coworkers in the
1960s and 1970s. The concept of GA is based on the biological evolution
which has been based on the principle of Charles Darwin’s theory of natural
selection (Yang, 2014). GA has the ability to deal with parallelism as well as
complex problems. Following is the procedure to find the optimization of a
mathematical expression or a complex control problem which can be also
described by a flow chart as shown in Fig. 9.9.
1. Firstly, the algorithm encodes the cost function or objective function
which has to be minimized.
2. After that selection criteria will be defined.
3. Further, random population of an individual solution will be created.

FIGURE 9.9 Flow chart of GA.