Cross-coupled fuzzy logic control for biaxial servomechanisms

This paper presents a design and implementation case study that focuses on contour of a biaxial CNC machine tools. However, it is difficult to obtain an accurate nonlinear mathematical model of cross-coupled multi-axis machine tools. In this paper we investigate an alternative to conventional approaches where we employ cross-coupled fuzzy logic controllers for improving contouring accuracy of multi-axis CNC machine tools. A new fuzzy rule-generated method which is based on a performance index of the contour error obtained from an online estimation algorithm is proposed. Experimental results have shown that the desired contouring accuracy can be achieved, and the proposed approach outperforms over uncoupled approaches. In conventional control, increasing contour feedrate for productivity may result in larger contour errors. However, the experimental results have shown that the performance of the proposed approach is still quite good with the increasing contour feedrate