A new geometric proof of super-twisting control with actuator saturation

In this note, the stability of an uncertain system with actuator saturation using super-twisting controller (STC) is analysed. First, a new proof of STC ensuring finite-time stability of the system is proposed using geometric method which gives a new gain conditions. Then, using the proposed proof the domain of attraction (DOA) is explicitly calculated for the system with bounded control

Output Tracking of Nonminimum-Phase Systems via Reduced-Order Sliding-Mode Design

In this paper, a method to design the reduced-order sliding-mode control is proposed for the robust output tracking of an arbitrary signal for nonminimum-phase systems. The main contributions in this paper include the design of the reduced-order switching function that ensures the asymptotic tracking of an arbitrary reference signal during sliding motion, the design of the reduced-order sliding-mode controller that enforces the sliding motion in finite time, and the computation of bounds on stable and virtually stable zero dynamics that is required for the output tracking. To show the effectiveness of the proposed design method, results of implementation on the experimental setup of an inverted pendulum system are also presented here

Comparative study of back-stepping controller and super twisting sliding mode controller for indirect power control of wind generator

© 2021 Springer. This is the accepted manuscript version of an article which has been published in final form at https://doi.org/10.1007/s13198-019-00905-7This paper presents the application nonlinear control to regulate the rotor currents and control the active and reactive powers generated by the Doubly Fed Induction Generator used in the Wind Energy Conversion System (WECS). The proposed control strategies are based on Lyapunov stability theory and include back-stepping control (BSC) and super-twisting sliding mode control. The overall WECS model and control scheme are developed in MATLAB/Simulink and the simulation results have shown that the BSC leads to superior performance and improved transient response as compared to the STSMC controller.Peer reviewe

Smooth integral sliding mode controller for the position control of Stewart platform

This paper proposes the application of a new algorithm for the position control of a Stewart platform. The conventional integral sliding mode controller is a combination of nominal control and discontinuous feedback control hence the overall control is discontinuous in nature. The discontinuity in the feedback control is undesirable for practical applications due to chattering which causes the wear and tear of the mechanical actuators. In this paper the existing integral sliding mode control law for systems with matched disturbances is modified by replacing the discontinuous part by a continuous modified twisting control. This proposed controller is continuous in nature due to the combinations of two continuous controls. The desired position of the platform has been achieved using the proposed controller even in the presence of matched disturbances. The effectiveness of the proposed controller has been proved with the simulation results. (C) 2015 ISA. Published by Elsevier Ltd. All rights, reserved

A New Algorithm for Continuous Sliding Mode Control With Implementation to Industrial Emulator Setup

This paper presents a new control algorithm for obtaining continuous sliding mode control, based on integral sliding-mode control (ISMC), where the discontinuous part of the ISMC is replaced with a continuous control. It is shown that the well-known super twisting control (STC), which replaces the discontinuous part of the ISMC acts as a disturbance observer, and hence, cancels the matched disturbance. As the overall controller is continuous the proposed method is advantageous over the existing ISMC, which has a discontinuous term. Also from the practical implementation point of view, in particular for mechanical systems, discontinuous term will result in chattering, which is undesirable. The proposed algorithm has been implemented on a practical system and its superiority has been demonstrated

A new geometric proof of super-twisting control with actuator saturation

In this note, the stability of an uncertain system with actuator saturation using super-twisting controller (STC) is analysed. First, a new proof of STC ensuring finite-time stability of the system is proposed using geometric method which gives a new gain conditions. Then, using the proposed proof the domain of attraction (DOA) is explicitly calculated for the system with bounded control. (C) 2017 Elsevier Ltd. All rights reserved

Simultaneous state and parameter estimation method for a conventional ozonation system

This article presents a simultaneous state (via a nonlinear form of Luenberger observer) and parameter (using a proportional–integral least mean square form) estimator design method for a conventional ozonation system. The suggested state observer assumes that the only available output signal is the concentration of the ozone gas at the output of the reactor. The estimation of the reaction rate constants of ozonation in the presence of contaminants uses the suggested proportional–integral estimation method. The convergence proof of the developed state-parameter identification method was confirmed using a Lyapunov based stability analysis. This analysis characterizes the quality of estimation considering the presence of modeled uncertainties and external perturbations. The implementation of the super-twisting algorithm as a robust and exact differentiator allowed to perform the estimation of the reaction rate constants of the ozonation, the temporal evolution of the dissolved ozone and the evolution of contaminants concentrations. The simultaneous state and parameter estimator design method was implemented in real-time using phenol as a model contaminant. The numerically simulated and real-time implementations showed that the method provides accurate estimates of the contaminant concentration and the reaction rate coefficient in all the evaluated cases

Implementation of Super-Twisting Control: Super-Twisting and Higher Order Sliding-Mode Observer-Based Approaches

In this paper, an output feedback stabilization of perturbed double-integrator systems using super-twisting control (STC) is studied. It is shown that when STC is implemented based on super-twisting observer (STO), then it is not possible to achieve second-order slidingmode (SOSM) using continuous control on the chosen sliding surface. Two methodologies are proposed to circumvent the above-mentioned problem. In the first method, control input is discontinuous, which may not be desirable for practical systems. In the second method, continuous STC is proposed based on higher order sliding mode observer (HOSMO) that achieves SOSM on the chosen sliding surface. For simplicity, we are considering here only the perturbed double integrator, which can be generalized for an arbitrary-order systems. Numerical simulations and experimental validation are also presented to show the effectiveness of the proposed method