Robust variable-gain backstepping control for nonlinear systems with real-time application to induction motor

This study proposes a novel variable-gain mechanism with a minimal number of tuning parameters to enhance the performance of conventional backstepping controllers for nonlinear systems while avoiding singularity and peaking phenomena. The proposed approach is simple, computationally efficient, and well suited for real-time implementation without imposing a significant computational burden. Its effectiveness is validated through real-time experiments conducted using a dSPACE DS1104 controller board and a 7.5-kW induction motor (IM). Simulation results demonstrate that the proposed controller outperforms the conventional backstepping controller. Robustness analyses under variations in stator resistance, load inertia, and viscous friction coefficient reveal substantial reductions in the integral squared error (ISE), from 42.78 to 0.73, 67.4 to 1.38, and 3.65 to 0.53, respectively. Experimental results further confirm that the proposed method achieves superior tracking performance and enhanced robustness against disturbances compared with existing methods reported in the literature.