Research of a Self-organizing Fuzzy PID Controller in LED die Source-measure System

The Auto LED die Mapping and Sorting System is a key manufacturing Equipment in LED production. This paper chooses the LED test system as experimental platform, based on which a precise and programmable multi-range digital Source-meter System (SMS) has been developed. In the embedded control part, a Self-organizing Fuzzy PID Controller (SFPID) is designed. a normalized acceleration as the indicator of system response speed is used to build up the self-organizing mechanism, in which the integral and derivative coefficients of the fuzzy PID controller (FPID) are adjusted in an online manner according to the system error, and the phases identified with the aid of the normalized acceleration in the control process. With the coefficients tuned, the mapping relation between the fuzzy sets of the input and output variables are changeable. Compared to three-dimensional FPID, by means of the normalized acceleration r_v(k), this SFPID can subtract the fuzzy rules obviously and reduce the control design complexity without decreasing the input dimensions. The results of calibration test to a red LED (STP60NF06) with the SMS show that the SMS response time is 2.88 mS, and the stable accuracy is 0.1%.