Authors : Md. Shabiul Islam, M.S. Bhuyan and Sawal H. Md. Ali
Abstract: This study describes a FPGA realization of a Fuzzy Logic Controller (FLC) algorithm for designing a Wheelchair Controller (WC). The controller enables the movement of wheelchair and makes brake in an unstructured environment by the WC sensor to avoid any encountered obstacles. The WC is found to be able to react to the environment appropriately during its navigation to avoid crashing with obstacles by turning to the proper angle while moving. To design the controller unit, a speed sensor and a distance sensor, etc. are placed in front of the wheelchair for its functionality. The numerous data is used to evaluate the algorithm which control an output signal for the brake-power using by the input signals of speed sensor and distance sensor. The FLC has proven a commendable solution in dealing with certain control problems when the situation is ambiguous. One of the main difficulties faced by conventional control systems is the inability to operate in a condition with incomplete and imprecise information. As the complexity of a situation increases, a traditional mathematical model will be difficult to implement. Fuzzy logic is a tool for modeling uncertain systems by facilitating common sense reasoning in decision-making in the absence of complete and precise information. In this study, the WC is designed based on the theories of fuzzy logic (such as fuzzifier, fuzzy rule base, inference mechanism and defuzzifier) and then simulated in MATLAB platform. The designed codes of WC also have written in VHDL language for implementing the hardware blocks of the separate modules of the WC. The verified VHDL code of the WC has been synthesized using Quartus II tool in Altera environment. Finally, the hardware designed codes have downloaded into FPGA board (APEX 20K200EF484) for the circuits functionality verification. From the timing analyzer report during implementation into FPGA board, it is observed that the longest delay from the source pin sel3 to destination pin LED7SEG1 is 24.019 nsec. Hence, the maximum clock speed (fmax) of the wheelchair is 41.63 MHz. During the experiment, researchers have set the hardware working frequency in 40 MHz to be confirmed the reliability in working condition.
Md. Shabiul Islam, M.S. Bhuyan and Sawal H. Md. Ali, 2013. FPGA Realization of a Fuzzy Based Wheelchair Controller. Research Journal of Applied Sciences, 8: 442-448.