Design of a single-input fuzzy logic controller and its properties

Most fuzzy logic controllers (FLCs) for minimum phase plants use an UNLP (Upper Negative and Lower Positive) or UPLN type control rule table. This property allows design of a single-input FLC using a sole input fuzzy variable, which is called the SFLC (single-input FLC). It greatly simplifies the design procedure of the conventional FLC and has many advantages. However, it is still difficult to adapt to varying operating conditions. We here design a single-input adaptive fuzzy logic controller (SAFLC) using a switching hyperplane introduced in sliding mode control. In the proposed SAFLC, some parameters of membership functions characterizing linguistic terms of fuzzy rules are adjusted by an adaptive law that directly incorporates linguistic fuzzy control rules into the controller. We also prove that 1) the closed-loop system is globally stable in the sense that all signals involved are bounded and 2) its tracking error converges to zero asymptotically. We perform computer simulation using an inverted pendulum system.

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Controller Design For A Pilot–Scale Heating And Ventilation System Using Fuzzy Logic Approach

Jurnal Teknologi ◽

10.11113/jt.v54.806 ◽

2012 ◽

Author(s):

Nurul Adilla Mohd Subha ◽

Mohd Fua’Ad Rahmat ◽

Kashif M. Ishaq

Keyword(s):

Fuzzy Logic ◽

Fuzzy Logic Controller ◽

Control Method ◽

Controller Design ◽

Ventilation System ◽

Pilot Scale ◽

Computational Time ◽

Distance Method ◽

Fuzzy Logic Approach ◽

Single Input

Dalam kajian ini, pengawal masukan tunggal logik kabur (SIFLC) direka bentuk dan dilaksanakan ke atas sistem VVS–400 dari Instrutek, Larvik, Norway. VVS–400 ini dimodelkan menggunakan struktur model ARX dan model kotak hitam untuk menerbitkan anggaran model matematik bagi sistem tersebut. Reka bentuk SIFLC menawarkan pengurangan yang signifikan dalam peraturan yang digunakan serta memudahkan proses mengawal parameter kawalan. Untuk mengesahkan keberkesanannya, kaedah pendekatan ini disimulasikan dengan anggaran model matematik bagi sistem VVS–400. Anggaran model matematik ini boleh di terbitkan menggunakan perisian pengenalpastian sistem di dalam Matlab. SIFLC telah memberikan beberapa kebaikan dan pembaikan prestasi jika dibandingkan dengan pengawal logik kabur (CFLC) kerana memerlukan peraturan yang mudah serta usaha yang sangat minimum ketika mengawal parameter kawalan. Ini dapat memendekkan masa pengkomputeran untuk menyelesaikan algoritma pengawal. Dalam simulasi, persamaan SIFLC dan CFLC dapat di lihat pada keluaran sistem. Kedua–duanya menghasilkan keluaran yang hampir sama. Namun, kebaikan SIFLC jelas membuktikan keluaran yang sama dapat dihasilkan dengan sedikit pengubahsuaian dari CFLC. Kata kunci: Pengawal logik kabur; VVS–400; kaedah jarak bertanda; pengawal masukan tunggal logik kabur; ARX In this paper, a Single–input fuzzy logic controller (SIFLC) is designed and applied on a nonlinear heating and ventilation plant VVS-400 developed from Instrutek, Larvik, Norway. VVS–400 is modeled using Auto–regressive with exogenous input (ARX) model structure and linear black–box technique. The proposed SIFLC offers significant reduction in rule inferences and simplify the tuning of control parameters. To verify its effectiveness, this control method is simulated with an approximated VVS–400 model. An approximated VVS–400 model is obtained using System Identification toolbox in Matlab. The SIFLC provides several advantages over conventional fuzzy logic controller (CFLC) due to its simple inference rule mechanism, require very minimum tuning effort and minimizing the computational time to accomplish the controller algorithm. Simulations validate the equivalency of both controllers. Results reveal that SIFLC and CFLC have almost similar output performance. However SIFLC requires very minimum tuning effort and has less computational time. Key words: Fuzzy logic controller; VVS–400; signed distance method; single–input fuzzy logic controller; ARX

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