Control Strategy for Smooth Wire Sending and Constant Tension in Multiwire Slicer

In a multiwire slicer, it is very crucial to keep wire sending smooth and tension constant to guarantee the quality of silicon wafers. Since the wire sending status has impact on the wire tension, it needs to be controlled to be smooth enough first. The measurement of the wire sending state is based on the two tensometers near the wire sending point and the tension adjusting unit, respectively. The measuring principle is given in detail. The smooth wire sending control is realized through a position adjusting unit. To achieve good control performance, the wire sending state is divided into several sections, and a novel feedforward multiconditioned P controller is designed. After the smooth wire sending controller is designed, the factors related to the wire tension vibration are analyzed deeply, and then, a self-tuning fuzzy controller is proposed. The parameters of the controller can be tuned according to the wire moving velocity. To show the validity of the proposed method, experiments on real platform are well conducted.