Modeling and Analysis on Stream-Tube of Pouring Flow with a Pair of Multi-Pendulum in Self-Transfer-Type Automatic Pouring Robot

摘要

Recently, self-transfer-type (STT) automatic pouring robot has been gradually developed to speed-up of pouring process. This robot moves to pour the molten metal into moving molds on the line. If the ladle and mold are transferred at high speed, the tact time can be shortened. In order to achieve that, liquid falling position must be accurately estimated in consideration of ladle's acceleration. The dynamics of the molten metal are needed which is considered about the liquid characteristics. The streamline of falling liquid can be shown if you use CFD (Computation Fluid Dynamics). However, it's difficult to calculate the falling liquid motion in real time, because its exact model comprised of Navier-Stokes and continuous equations are complicated. Accordingly, we present a novel model to predict liquid falling position. This model is simple constructed by using a pair of multi-pendulum. The advantage of proposed model is that it can predict the stream-tube and then the falling position of the future, when the transfer inputs are determined. In the proposed model, the weights are connected between two multi-pendulums as ladder. These weights pull the multi-pendulum toward the center, which can express the shrink of stream-tube during liquid falling. The active forces on the falling liquid are expressed by the balance of tensile force. The sizes of masses are identified with the pressure which is works on the pouring liquid surface. Through water experiments and model simulation, it is clarified that the proposed model is well agreed with actual phenomenon. The falling position control system with the proposed model will be constructed, which can be designed the transfer velocities in real time by using the predicted falling position of molten metal.