This paper investigates the effect of quantization gain factors, at the input side, and the scaling gain, at the output side, of a fuzzy controller. A fuzzy control system is designed with two main parts: a basic fuzzy controller (BFC) which produces the output control signal and supervisor fuzzy controllers (SFCs) to continuously adjust, on-line, the I/O scaling or gain factors of the (BFC) in order to improve its performance against different dynamic operating conditions. The designed self tuning controller is used to position control of a DC motor with un known parameters according to the feed back inputs, a tracking error (e) and change of error (Δe), based on the proposed fuzzy rules. The system implementation and tests are carried out using LabVIEW software ( V8.2 ) with a data acquisition card type (NI PCI-6251) from National Semiconductors to achieve real time measurements.
Keywords: self-tuning, fuzzy controller, position control, scaling gain, LabVIEW .