Fuzzy logic control of a positioning table with DSP real-time implementation

Recently numerous advanced control techniques have been developed for motion control of electromechanical systems containing unknown parameters and uncertainties such as variations in payloads and unmodeled friction. Due to the limitation of sampling rates in low-cost, general-purpose microprocessors, it is difficult to implement those advanced algorithms in real-time for industrial applications. This is particularly true for high-speed and high precision control of various motion devices. In this paper we develop a rule-based fuzzy logic controller (FLC) for trajectory tracking control of an x-y axis positioning table. Using a DSP-based real-time control testbed, we were able to perform experiments with different sampling frequencies, motion speeds, and payloads. The effects of these parameters on the control performance are examined. The control performance of the FLC system proposed here is compared experimentally with that of a conventional PI control system. The results demonstrate the effectiveness of the proposed control system, especially for high-speed and high precision control of the x-y table with parameter variations