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Abstract In this paper, an Optimal Super-Twisting Algorithm (OSTA) with time delay estimation is designed based on Input/Output feedback linearization for uncertain robot manipulators. The design procedure consists on three steps. Firstly, an Input/Output feedback linearization is applied to transform the nonlinear model into a linear equivalent one. Secondly, by defining a quadratic performance, an optimal sliding surface will be designed. Finally, a super-twisting algorithm with time delay estimation is proposed for high accuracy tracking trajectory. Lyapunov theory is used to prove the finite-time convergence of the sliding surface and its derivative. This structure is used to estimate unknown dynamics and to reduce the control effort and the chattering phenomenon. Highlights • The problem of trajectory tracking for uncertain robot manipulators is addressed. • An equivalent linear system is obtained using Input-Output Feedback Linearization. • An optimal sliding surface is designed based on the obtained linear system. • Combination of STA and TDE method is proposed and the stability is proved. • Simulation and experimental results are presented and compared to other controllers. [ABSTRACT FROM AUTHOR]

In this manuscript, the high-accuracy stator currents tracking issue is considered for a six-phase induction motor subject to external perturbations and uncertainties due to unmeasurable rotor currents and electrical parameter variations. To achieve the control goals, the common two-cascade controllers structure is required for this type of motor. The first controller in the outer loop consists of a proportional integral to regulate the speed. Then, the second is the proposed inner nonlinear stator currents controller based on a robust discrete-time terminal super-twisting algorithm supported by the time-delay estimation method. For the design procedure, the discrete-time stator currents dynamics are derived; for example, the vector of the matched perturbations and unmeasurable rotor currents are specified to simplify the estimation. A detailed stability analysis of the closed-loop error dynamics using Lyapunov theory is given. Finally, a real asymmetrical six-phase induction motor is used to implement in real-time the developed method and to illustrate its effectiveness and robustness. The results obtained reveal a satisfactory stator currents tracking in steady state and transient conditions and under variation in the magnetizing inductance. Moreover, a comparative study with an existing method in steady state for two different rotor speeds is presented to show the superiority of the proposed discrete-time technique. [ABSTRACT FROM AUTHOR]