Sliding mode control of quadruple tank process

The process investigated herein is the quadruple tank system that is stable only within a limited zone of operating parameters. The process model has been developed from fundamentals and tuned with experimental data. A controller design based on feedback linearization has been tested on this process model. Coupling feedback linearization with sliding mode algorithm provides robust control of the process and performs far superior to conventional PI control. A PC based controller interfaced to the experimental quadruple tank experimental set up has been used to implement this algorithm and test its performance. Inserting a ‘boundary layer’ around the sliding surface reduced the ‘chattering’ associated with sliding mode control. The implemented controller provides robust control and excellent set point tracking.