Higher order sliding mode-based robust stabilisation of fluid-flow model of TCP/AQM scheme

Abstract

This paper deals with the stabilisation of TCP/AQM scheme from robust control theory perspective. A higher order sliding mode-based controller for the robust stabilisation of indeterminate system is proposed. Fluid-flow model of TCP-queue dynamics proposed in literature is a continuous uncertain system having matched and unmatched uncertainties in both system and input matrices. A novel sliding surface is designed with the aid of quadratic Lyapunov function with constant Jacobian matrix of coefficients in a special form. A second order sliding mode (super twisting) control law is synthesised which gives robustness with respect to matched uncertainties and at the same time reduces the chattering effect due to the continuous nature of the algorithm. The system is exponentially stabilised and the simulation results justify the efficacy of the proposed controller.