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Design of Fractional Order Fuzzy Sliding Mode Controller Chapter | 9  267



               TABLE 9.4 Optimized Gain Parameters of IOSMCPD and FOFSMCPD
               Controllers
               Parameters                        IOSMCPD       FOFSMCPD
                                                Link-1 Link-2  Link-1  Link-2
               Normalized fuzzy input gain                    314.42  228.73
               Exponential law gains          311.74   87.60  128.16  58.92
                                     g  E
                                               43.58  220.53  174.46  157.71

                                     g
                                      k
               Boundary layer ΔðÞ               0.64    0.64    0.77   0.77
               Sliding surface error gain λ    38.88   38.88   38.97  38.97
                                ðÞ
               Integer / Fractional order for   1       1       0.89   0.53
               derivative αðÞ


                   0.8
                                                               IOSMCPD
                                                               FOFSMCPD
                   0.6            × 10 –3
                 Objective function  0.4  2.2 2 96.396 96.398  96.4 96.402 96.404 96.406


                                1.8
                                1.6
                   0.2


                    0
                     0    10   20   30   40   50   60   70   80   90  100
                                           Generation
             FIGURE 9.10 Objective functions versus iteration curve for IOSMCPD and FOFSMCPD
             controllers.
             this figure that the convergence of the FOFSMCPD controller is better than
             the IOSMCPD controller. The value of objective functions obtained for the
             IOSMCPD controller is 0.0020 whereas for the FOFSMCPD controller it is
             0.0017 for trajectory tracking task as depicted in Table 9.5. An improvement
             of 18.18% is obtained in IAE by the FOFSMCPD over the IOSMCPD con-
             troller for link-1 whereas link-2 offered the same IAE values by both the
             controllers. About 15% improvement in objective functions has been
             obtained by the FOFSMCPD on the IOSMCPD controller. Reference trajec-
             tory tracking curves for both links, their controller outputs, and error curves
             are shown in Figs. 9.12 9.14. A careful observation is obtained from
             Fig. 9.13 that after taking the value of chatter in the account of objective
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