Contouring error control of machine tool drives with backlash compensation

This article presents ideas for contour error control of machine tools. A demonstration of these ideas is performed on a biaxial drive system exhibiting linear and circular contouring. A new independent contour error control (ICEC) strategy, which utilizes the equations of the well-known cross-coupling controller, is shown to diminish a linear contour error without using any cross-feeding signals between the driving axes. For circular contouring, new exact equations for contour error calculations are presented. These exact equations may lead to some significant control strategies that can be based on the cross-coupling control (CCC) concept. One new CCC strategy, based on one of these exact contour error equations, is shown to be very promising for circular contouring. Finally, the proposed strategies have been further developed for either independent or cross-coupling backlash compensation. These backlash compensation schemes may save complications of having special means for backlash control if CCC systems are intended for implementation.