Experimental evolutionary programming-based high-precision control

Conventional linear control schemes often fail to provide precise positioning of a control object under the influence of friction, deadzone, saturation, etc. This article proposes a high-precision control scheme for a precise point-to-point positioning system, called an X-Y table, even under the above-noted influences. The proposed scheme is composed of a fuzzy precompensator and a PD controller. The fuzzy precompensator is employed to improve the performance of the PD controller. Its fuzzy rules are obtained from experimental evolutionary programming (EEP), not from an expert. The effectiveness of the scheme is demonstrated by experiments on the X-Y table, with a positioning error of less than 1 μm and settling time of less than 0.15 s, where the maximum velocity and acceleration are 0.25 m/s and 1.7 m/s², respectively.