Parallel control structure based sliding mode controller for second order unstable processes with Dead-Time

Document Type : Article


Department of Electrical Engineering, National Institute of Technology Patna, Patna, India


As one or more poles are located on the right side of the s-plane, the unstable processes are challenging to control. The presence of dead time in such systems makes control much more difficult. This work focuses on the control of unstable processes with dead-time using sliding mode control in parallel control structure. Two controllers for set-point tracking and load-disturbance rejection are designed with PIDA based sliding surface. The parameters of continuous and discontinuous control law are obtained using particle swarm optimization technique. An objective function is constituted in terms of performance measure (integral absolute error). The proposed sliding mode controller design in parallel structure gives enhanced set-point tracking and load disturbance rejection. Illustrative examples demonstrate the superiority of the proposed controller over earlier reported work in this realm, especially in terms of load rejection. Furthermore, robustness of the proposed controller is also investigated by inclusion of perturbations in the parameters. The obtained results clearly show how well the suggested controller works.


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