FPGA BASED P/PI/PD/PID-LIKE INTERVAL TYPE -2 FLC DESIGN FOR CONTROL SYSTEMS

Abstract

Type-2iFuzzyilogicicontrol contains footprint of uncertainty (FOUi) that is able to handle the numerical uncertainties, nonlinearities, and linguistic associated with the inputs and outputs. This paper presents the structure of P/PI/PD/PID-like Interval Type-2 Fuzzy Logic Controller (IT2-FLC) that is designed and simulated using MATLAB SIMULINK. This controller is designed by combining the advantages of fuzzy inference and different structures of controller. The type of the controller is selected using two bits control inputs. The inputs to the controller are: input-output gains, set-point, and the actual output. Karnick-Mendel (KM) algorithm is used to implement the IT2-FLC. IT2FLC has two triangular shaped membership functions. The range of the universe of discourse (-1.5 to 1.5) is selected for each input and output. The defuzzification technique is selected as Centroid method. The sampling time is (0.01), and the choice of rules is by using trial and error. The programs are written in MATLAB SIMULINK and converted into VHDL and Verilog languages. The program generated must achieve small FPGA size and as a result less execution time must achieve vs. acceptable accuracy. Linear and nonlinear models were used to test the Controller. Trial and error method was used to tune the gain factors to obtain the best response with minimum overshoot, minimum settling time, minimum Root Mean Squared Error (RMSE), and minimum structure design.