Abstract: In order to improve the experimental teaching of relevant courses in automatic control, the design of a four-tank system is presented. The hardware is composed of general industrial components, while a Matlab programming environment is used for the software to directly control the system. A graphical user interface is also adopted to provide an easy way to run the system. The four-tank system model is built, and its parameters are identified based on a step response experiment. Furthermore, a distributed internal mode controller is designed for the liquid tracking control of the four-tank system. The results show that the four-tank system, using the internal mode controller, has little effect on the water level of the other tank when the water level of one tank changes, and the system has a satisfactory control effect. This experiment could play an important role in the teaching of relevant courses in automatic control.

Key words: four-tank system, Matlab / graphical user interface ( GUI ) operation interface, internal model control, distributed control