@article{MAKHILLRJAS2013899330,
    title = {FPGA Realization of a Fuzzy Based Wheelchair Controller},
    journal = {Research Journal of Applied Sciences},
    volume = {8},
    number = {9},
    pages = {442-448},
    year = {2013},
    issn = {1815-932x},
    doi = {rjasci.2013.442.448},
    url = {https://makhillpublications.co/view-article.php?issn=1815-932x&doi=rjasci.2013.442.448},
    author = {Md. Shabiul,M.S. and},
    keywords = {Wheelchair controller,fuzzy logic rules,VHDL,dynthesis,FPGA},
    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 circuit’s 
  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.}
    }