Flow rate estimation using unscented Kalman filter in automatic pouring robot

We describe here a method for estimating the pouring flow rate for tilting-ladle-type automatic pouring robot used in casting industries. To precisely pour molten metal into the mold, controlling the flow rate of liquid flowing out of the ladle is mandatory. However, it is difficult to directly measure the pouring flow rate by using a conventional flow meter, because the flow meter is damaged by the high temperature molten metal. Therefore, in this study, we used a soft sensing technique as part of the pouring flow rate estimation system. The extended Kalman filter was applied to the flow rate estimation of the automatic pouring robot in previous study. The previous approach can be applied only the ladle with smooth shape, because of derivation of Jacobian matrix. However, some ladles with complicated shape which the Jacobian matrix cannot be derived have been used in an actual casting plant. In this paper, an unscented Kalman filter which does not need the Jacobian matrix is applied into the flow rate estimation. The effectiveness of the proposed flow rate estimation method is demonstrated through simulations and experiments.