Abstract: A program-controlled system used for the high frequency fatigue testing machine i?introduced in this paper. The 8031 single chip microcomputer is taken as the kernel of control elements in the developed system, it will transform the static and dynamic load data inputted by users on keyboard into the load control signals of the fatigue testing machine with two 12-bit D / A converters and simultaneously sample the load signals from the prior amplifer through a multiplexer, a sample-hold and a 12-bit A / D converter, then make the automatic regulation of the dynamic and static loads based on the load errors and load error rates in accordance with the fuzzy principle so that the closed-loop controls to the dynamic and static loads are realized. The counting of the dynamic load cycles is made by INT1 interruption activated by the prior amplifier signal processed through regulation and differentiation circuts.

Key words: program-controlled system, dynamic load, static load, fuzzy control