Automatic Control of a Concrete Distributor in a Floor Slab Element Precasting Plant

An important task in a floor slab element precasting plant is the distribution of concrete onto predefined areas on a pallet. Problems arise through disturbances caused by changing concrete consistency, the geometery of the floor slab elements, and the dynamics of the plant and measurement instrumentation. The solution to this difficult task is, to control the speed of the machine traversing the pallet and to control flap valves in the direction perpendicular to the direction of motion. The speed control is achieved using a discrete PID-controller with superimposed compensation for the nonlinear plant behaviour. In the paper, the following results are presented: modelling of the machine, simulation of the dynamic behaviour, controller design and its implementation on a microcomputer. Several simulation results and actual measurements in the plant are presented.