This paper deals with the design of sliding mode controller (SMC) with proportional plus integral sliding surface for regulation and tracking of uncertain process control systems. However, design method requires linear state model of the system. Tuning parameter of SMC has been determined using linear quadratic regulator (LQR) approach. This results in optimum sliding surface for selected performance index. Matched uncertainty is considered to obtain the stability condition in terms of its upper bound. A conventional state observer has been used to estimate the states. The estimated states are then fed to controller for determining control signal. The simulation study and experimentation on real-life level system have been carried out to validate performance and applicability of the proposed controller.
