Novel Super Twisting Observer Based Integral Terminal Sliding Mode Control for MIMO Nonlinear Systems With Uncertainties*

In this article, a novel super twisting observer (STO) based integral terminal sliding mode control (ITSMC) strategy is proposed to discuss the multi-input multi-output (MIMO) nonlinear systems with uncertainties. Firstly, the idea of proportion-integration-differentiation (PID) is introduced to design the integral-type terminal mode function. Secondly, the exponential reaching law is proposed to improve the convergence speed of sliding mode variables. The super twisting estimation algorithm is utilized to deal with the problem of model uncertainty and external disturbance of the system. Further, the ITSMC-STO strategy is constructed to improve the control performances which are tracking accuracy and anti-disturbance. Finally, the simulation results by the two-tank liquid level system as a typical process example is applied to confirm that the strategy proposed has good performances than the other methods.