Sliding mode controller with state observer for TITO systems with time delay

2017 ◽  
Vol 6 (2) ◽  
pp. 799-808 ◽  
Author(s):  
C. B. Kadu ◽  
A. A. Khandekar ◽  
C. Y. Patil
2020 ◽  
Vol 143 (2) ◽  
Author(s):  
Lyes Nechak

Abstract This paper is dedicated to the robust nonlinear control of friction-induced vibrations (FIV), more particularly those generated according to the mode-coupling mechanism. A nonlinear scheme which consists of a sliding-mode controller implemented by using a high-gain state observer is proposed. The main objective is to suppress or mitigate the generated vibrations by taking into account of the nonlinearities and uncertainties inherent to friction systems. Hence, this study proposes the analysis of the closed-loop performances of the high-gain observer-based sliding-mode controller when used for the active control of vibrations issued from the mode-coupling mechanism. Based on numerical simulations, the proposed controller has shown suitable performances distinguished from an effective suppress of the generated vibrations. Otherwise, it is shown that the gain of the used nonlinear state observer must be tuned in order to ensure a suitable compromise between the robustness level of the performances with respect to parameter uncertainty and the robustness level with respect to the measurement noise.


2021 ◽  
Vol 2021 ◽  
pp. 1-19
Author(s):  
Ouxun Li ◽  
Ju Jiang ◽  
Li Deng ◽  
Shutong Huang

Aiming at the uncertainty and external disturbance sensitivity of the near space vehicles (NSV), a novel sliding mode controller based on the high-order linear extended state observer (LESO) is designed in this paper. In the proposed sliding mode controller, the double power reaching law is adopted to enhance the state convergence rate, and the high-order LESO is designed to improve the antidisturbance ability. Moreover, the appropriate observer bandwidth and extended order are selected to further reduce or even eliminate the disturbance by analyzing their influences on the observer performance. Finally, the simulation demonstrations are given for the NSV control system with uncertain parameters and external disturbances. The theoretical analyses and simulation results consistently indicate that the proposed high-order LESO with carefully selected extended order and observer bandwidth has better performance than the traditional ones for the nonlinear NSV system with parametric uncertainty and external disturbance.


2020 ◽  
Vol 17 (3) ◽  
pp. 172988142092642
Author(s):  
Yaoyao Wang ◽  
Rui Zhang ◽  
Feng Ju ◽  
Jinbo Zhao ◽  
Bai Chen ◽  
...  

To effectively reduce the mass and simplify the structure of traditional aerial manipulators, we propose novel light cable-driven manipulator for the aerial robots in this article. The drive motors and corresponding reducers are removed from the joints to the base; meanwhile, force and motion are transmitted remotely through cables. Thanks to this design, the moving mass has been greatly reduced. In the meantime, the application of cable-driven technology also brings about extra difficulties for high-precise control of cable-driven manipulators. Hence, we design a nonsingular terminal sliding mode controller using time-delay estimation. The time-delay estimation is applied to obtain lumped system dynamics and found an attractive model-free scheme, while the nonsingular terminal sliding mode controller is utilized to enhance the control performance. Stability is analyzed based on Lyapunov theory. Finally, the designed light cable-driven manipulator and presented time-delay estimation-based nonsingular terminal sliding mode controller are analyzed. Corresponding results show that (1) our proposed cable-driven manipulator has high load to mass ratio of 0.8 if we only consider the moving mass and (2) our proposed time-delay estimation-based nonsingular terminal sliding mode is model-free and can provide higher accuracy than the widely used time-delay estimation-based proportional–derivative (PD) controller.


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