Fuzzy control of a heat-bending system

This paper discusses the problems associated with detecting displacement phenomena during a NC-controlled heat-bending process. To ensure accurate heat-bending results, it is necessary to control the displacement of a point located at the edge of the plate undergoing heat bending. This is achieved by varying the operating parameters of the numerical control heat-bending (NCHB) machine, e.g. the ratio of Q/V where Q represents the heat input intensity and V the speed of the servomotor driving the heat source (an oxy-acetylene torch in this particular study). It is not easy to accurately predict the plate shape after heating along multiple heating lines. Furthermore, it is difficult to describe the state equation for the dynamic behavior of the displacement since the heat-bending phenomena are described by partial differential equations representing elasto-plastic behavior. In order to predict and control the plate shape after heat bending, this paper proposes a method which combines the inverse method and fuzzy control. Using this method, it is possible to estimate the displacement and, therefore, the plate shape, based upon the values of Q and V, and the position of the heating lines.