Sliding motion accuracy of proxy-based sliding mode control subjected to measurement noise and disturbance

Author(s):  
Ryo Kikuuwe
Energies ◽  
2021 ◽  
Vol 14 (11) ◽  
pp. 3011
Author(s):  
Paweł Latosiński ◽  
Andrzej Bartoszewicz

Sliding mode control strategies are well known for ensuring robustness of the system with respect to disturbance and model uncertainties. For continuous-time plants, they achieve this property by confining the system state to a particular hyperplane in the state space. Contrary to this, discrete-time sliding mode control (DSMC) strategies only drive the system representative point to a certain vicinity of that hyperplane. In established literature on DSMC, the width of this vicinity has always been strictly greater than zero in the presence of uncertainties. Thus, ideal sliding motion was considered impossible for discrete-time systems. In this paper, a new approach to DSMC design is presented with the aim of driving the system representative point exactly onto the sliding hyperplane even in the presence of uncertainties. As a result, the quasi-sliding mode band width is effectively reduced to zero and ideal discrete-time sliding motion is ensured. This is achieved with the proper selection of the sliding hyperplane, using the unique properties of relative degree two sliding variables. It is further demonstrated that, even in cases where selection of a relative degree two sliding variable is impossible, one can use the proposed technique to significantly reduce the quasi-sliding mode band width.


Energies ◽  
2021 ◽  
Vol 14 (7) ◽  
pp. 1882
Author(s):  
Piotr Leśniewski ◽  
Andrzej Bartoszewicz

In this paper, discrete time reaching law-based sliding mode control of continuous time systems is considered. In sliding mode control methods, usually the assumption of bounded absolute values of disturbances is used. However in many cases, the rate of change of the disturbance is also bounded. In the presented approach, this knowledge is used to improve the control precision and reduce the undesirable chattering. Another advantage of the proposed method is that the disturbance does not have to satisfy the matching conditions. In the paper two new reaching laws are analyzed, one of them ensures the switching quasi-sliding motion and the other the non-switching motion. For both of them, the robustness is assessed by calculating the quasi-sliding mode band width, as well as the greatest possible state error values. Specifically, the state errors are not considered only at the sampling instants, as is usual for discrete time systems, but the bounds on the continuous values “between” the sampling instants are also derived. Then, the proposed approaches are compared and analyzed with respect to energy expenditure of the control signal.


2021 ◽  
Vol 118 (2) ◽  
pp. 215
Author(s):  
Yin Fang-Chen ◽  
Wu Xiang-Cheng

This paper introduces a linear quadratic sliding mode control (LQ-SMC) scheme into a looper control system. First, according to a 1700 mm tandem hot mill, the state-space dynamic model of the looper system was established, and then, the optimal control law of the looper system was obtained based on the established model. Finally, the optimal sliding mode and optimal sliding mode control law of the LQ-SMC scheme were designed such that the sliding motion could satisfy the optimal value of the quadratic performance index. Simulation results show that the proposed control scheme has complete robustness to external disturbances that satisfies certain conditions, and the coupling between the looper angle dynamic and strip tension dynamic is also minimized.


Author(s):  
Omolbanin Yazdanbakhsh ◽  
Saeid Hoseinia

This paper investigates the chaos synchronization problem for a class of uncertain unified chaotic systems with external disturbances. Based on the proportional-integral (PI) switching surface, a sliding mode controller (SMC) is derived to not only guarantee the occurrence of a sliding motion of error states, but also reduce the effect of external disturbances to an H∞-norm performance. Also, a new reaching law is introduced to reduce the chattering problem that is produced by traditional sliding mode control. The parameters necessary for constructing both PI switching surface and the SMC can be found by the linear matrix inequality (LMI) optimization technique. Finally, a numerical simulation is presented to show the effectiveness of the proposed method.


2019 ◽  
Vol 29 (3) ◽  
pp. 517-525 ◽  
Author(s):  
Andrzej Bartoszewicz ◽  
Katarzyna Adamiak

Abstract This study presents a new, reference trajectory based sliding mode control strategy for disturbed discrete time dynamical systems. The desired trajectory, which is generated externally according to an existing switching type reaching law, determines the properties of the emerging sliding motion of the system. It is proved that an appropriate choice of the trajectory generator parameters ensures the existence of the quasi-sliding motion of the system according to the definition by Gao et al. (1995) in spite of the influence of disturbances. Moreover, the paper shows that the application of the desired trajectory based reaching law results in a significant reduction in the quasi-sliding mode band width and errors of all state variables. Therefore, in comparison with Gao’s control method, the system’s robustness is increased. The paper also presents an additional modification of the reaching law, which guarantees a further reduction in the quasi-sliding mode band in the case of slowly varying disturbances. The results are confirmed with a simulation example.


2005 ◽  
Vol 127 (3) ◽  
pp. 292-295
Author(s):  
Wu-Chung Su ◽  
Sergey V. Drakunov ◽  
U¨mit O¨zgu¨ner ◽  
Keith Redmill

Implementation of discrete-time sliding mode control on a sampled-data system leads to sliding motion in an OT2 boundary layer of the discontinuity surface, where T is the sampling period. A truss panel structure vibration control experiment is conducted to demonstrate the effectiveness of the proposed method. This paper utilizes a truncated model to characterize the models of interest and treats all the high frequency modes as disturbances. The experiment includes system identification, state observer design, and discrete-time sliding mode control.


2017 ◽  
Vol 40 (10) ◽  
pp. 3232-3238
Author(s):  
Yonghui Liu ◽  
Yugang Niu

This paper considers sliding mode control for a class of uncertain switched systems with state and input delays. In the control systems, each subsystem is not required to share the same input channel, which is usually assumed in previous works. By employing a weighted sum of the input matrices, a common sliding surface is designed. The sliding surface includes a predictor to compensate for the input delay of the control systems. To guarantee the asymptotic stability of the sliding motion, a switching signal based on the min-projection strategy is proposed. Moreover, it is shown that the state trajectories can be driven onto the specified sliding surface despite the presence of state and input delays and external disturbances. Finally, a numerical example is given to demonstrate the effectiveness of the proposed method.


2013 ◽  
Vol 380-384 ◽  
pp. 476-479 ◽  
Author(s):  
Xiu Qin Yang ◽  
Kai Feng Zou

In paper, the problem of robustify LQR for a class of uncertain linear systems is considered. An optimal controller is designed for the nominal system and an integral sliding surface is constructed. The ideal sliding motion can minimize a given quadratic performance index, and the reaching phase, which is inherent in conventional sliding mode control, is completely eliminated. Then the sliding mode control law is synthesized to guarantee the reachability of the specified sliding surface. The system dynamics is global robust to uncertainties which satisfy matching conditions. A GROSMC is realized. To verify the effectiveness of the proposed scheme, a robust optimal sliding mode controller is developed for rotor position control of an electrical servo drive system.


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