This article proposes a finite-time disturbance observer-based modified super-twisting algorithm (FDO-STA) for disturbed high-order integrator-chain systems under matched and mismatched disturbances. We first design a...
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This article proposes a finite-time disturbance observer-based modified super-twisting algorithm (FDO-STA) for disturbed high-order integrator-chain systems under matched and mismatched disturbances. We first design a finite-time observer for disturbance estimation, in which we show the finite-time convergence of disturbance estimation errors to zero. Second, by employing the estimates of disturbances and their derivatives, a new dynamic sliding surface is derived, which ensures the finite-time convergence of the controlled output to zero in the sliding phase. Then, based on the estimates of disturbances and their derivatives, the designed sliding surface, and a modified super-twisting algorithm, we develop the FDO-STA, which guarantees the finite-time convergence of the sliding variable to zero in the reaching phase. Rigorous analysis is provided to show the finite-time stability of the overall closed-loop system under the proposed control scheme. We finally apply the proposed FDO-STA framework to the path following control for fixed-wing UAVs under wind disturbances. Various simulation results are provided to show the effectiveness of the proposed controller, compared with the existing control approaches.
In this paper, a novel robust collective blade pitch controller (CBPC) is proposed for the semisubmersible floating offshore wind turbine (FOWT) above the rated wind speed. The proposed CBPC is based on the modified s...
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In this paper, a novel robust collective blade pitch controller (CBPC) is proposed for the semisubmersible floating offshore wind turbine (FOWT) above the rated wind speed. The proposed CBPC is based on the modifiedsuper-twisting sliding-mode (MSTSM) algorithm. Firstly, based on a control-oriented model of the semi-submersible FOWT, the dynamics of the rotor speed and the platform pitch rate considering the lumped disturbances, which consist of external disturbances, parametric uncertainties and unmodeled dynamics, are derived. Afterward, the MSTSM algorithm-based CBPC (MSTSM-CBPC) is designed for regulating the generator power to its rated value and reducing the platform pitching motion. Comparative co-simulation tests among the gain-scheduling proportional-integral CBPC, the standard STSM algorithm-based CBPC and the proposed MSTSM-CBPC are performed. Simulation results validate the effectiveness and the superiority of the proposed MSTSM-CBPC.
This article proposes a real-time maximum tire-road friction tracking control method with disturbance compensation for aircraft antiskid braking system (ABS). Conventional aircraft ABS cannot accurately set the optima...
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This article proposes a real-time maximum tire-road friction tracking control method with disturbance compensation for aircraft antiskid braking system (ABS). Conventional aircraft ABS cannot accurately set the optimal slip ratio in real time for runways with different friction characteristics, resulting in the maximum tire-road friction not being completely utilized in real time. To address this problem, first, a runway identification method is developed to determine the optimal slip ratio of the initial runway. Then, an optimal slip ratio update algorithm based on the Burckhardt model is proposed to update the optimal slip ratio according to the tire-road friction characteristics. Adaptive forgetting factor recursive least squares is employed to handle the most important parametric uncertainty in aircraft ABS, i.e., the brake torque conversion factor. The residual uncertainties and external disturbances are observed by constructing an extended state observer (ESO). In addition, by effectively integrating modified super-twisting algorithm with ESO, a continuous and chattering-free slip ratio tracking algorithm with disturbance compensation is developed. The proposed method can eliminate the adverse effects of major parametric uncertainties and greatly reduce the burden on ESO, so it achieves accurate tracking while greatly reducing the feedback gain. Finally, the effectiveness of the proposed method is verified by comparative simulation and experimental results.
This paper presents a fault diagnosis strategy for actuators faults in an octorotor unmanned aerial vehicle (UAV) using sliding modes techniques. First, system states are estimated using a second order sliding-mode ob...
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ISBN:
(纸本)9783952426937
This paper presents a fault diagnosis strategy for actuators faults in an octorotor unmanned aerial vehicle (UAV) using sliding modes techniques. First, system states are estimated using a second order sliding-mode observer (SOSMO) based on the modified super-twisting algorithm. Second, faults are estimated by considering the system control as an unknown input. After the convergence of the observer, the equivalent output injection is used to estimate the unknown input and thus to identify losses in the actuators. The effectiveness of this approach is illustrated by numerical simulations on Matlab/Sinnolink, and also a real experimental application on a coaxial octorotor UAV.
This paper proposes a model reference adaptive sliding mode control (MRASMC) scheme that uses time delay estimation (TDE) technique and adaptive modified super-twisting algorithm (AMSTA), then applies the scheme to ov...
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This paper proposes a model reference adaptive sliding mode control (MRASMC) scheme that uses time delay estimation (TDE) technique and adaptive modified super-twisting algorithm (AMSTA), then applies the scheme to overhead crane with uncertainties to ensure the payload can be transported to the desired position rapidly while simultaneously eliminating swing. Firstly, a desired reference model for improving transient performance was designed. More specifically, a new chattering-free reaching law is designed to achieve fast convergence of system state errors and improve system transient performance. To enhance the control performance, then, a time-delay estimation is employed to approximate the uncertainties and control law is designed based on modified adaptive super-twistingalgorithm, which can reduce the chattering phenomenon and achieve finite-time convergence. The stability and convergence of the controlled system is analyzed using Lyapunov theory. Moreover, Simulation results are presented to illustrate the effectiveness of the proposed controller.
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