Sliding Mode Control of an Exothermic Continuous Stirred Tank Reactor

A continuous action state-feedback sliding mode controller (SMC) is developed for nonlinear systems under the influence of disturbances not in the span of control input space. Constraints are imposed on the control action and its rate of change. These developments are then applied to the design of a SMC system to maintain a constant outlet product concentration in an exothermic continuous stirred tank reactor (ECSTR). Robustness with respect to model uncertainties of the example reactor control system is demostrated. System performance is analyzed for set-point regulation, Damköhler number variations and disturbance rejection. Simulations demonstrate fast and safe control.