Control of the filling ratio in the screw conveyer

In the granular transport system composed of a screw conveyer and a hopper, in order to supply the granules quantitatively and transport it efficiently, a outflow rate from the screw conveyer and a filling ratio inside a trough must be controlled at the same time. As the first step, the cotrol of the filling ratio is discussed in this paper. As a control algorithm, generalized predictive cotrol (GPC) method which is useful to a non-minimum phase process with variable dead-time is applied to the screw conveyer process. Moreover GPC algorithm which includes a filter 1/T (z^<-1>) is applied to the process. Their control performances are examined. Finally, the following results are obtained through simulations and experiments. 1) Good response waves for a set-point change and a disturbance input are obtained and granular materials can be transported under the optimal filling ratio by applying the GPC algorithm to the screw conveyer process. 2) By introducing the filter 1/T (z^<-1>) into the GPC algorithm, fluctuation of manipulating variable and controlled variable are suppressed.