Abstract: In order to restrain the extra torque and improve the loading precision of servo system load simulator, a fuzzy-PID torque controller based on grey prediction was proposed. According to the variation trend of the data measured by sensors, the grey prediction model predicted the future values of loading torque circularly, and took those prediction values as the operation basis of the torque controller. When the error was large, the controller performed a switch control; while the error was small, the controller performed a fuzzy-PID control. Meanwhile, a flexible factor depending on error was introduced to adjust the universe of the input variable dynamically and enhance the control ability of the fuzzy controller. The simulation and experiment results show that, compared with the traditional PID control, the proposed control strategy can reduce the extra torque by about one half, and therefore, it can be used to control the dynamical loading of servo systems.

Key words: automatic control technology, servo system, grey prediction, fuzzy-PID control, variable universe, load simulator