Robust control by fuzzy sliding mode (original) (raw)

A new fuzzy sliding mode control scheme

Proceedings of the 3rd World Congress on Intelligent Control and Automation (Cat. No.00EX393), 2000

Absrrucr-In this paper, a new fuzzy sliding mode control scheme is proposed for second-order linear timevarying systems in order to obtain faster error convergence and desired error dynamics. It is well known that a second-order linear time-varying system can be used to model higher order linear time invariant systems piece-wisely. Therefore, it is necessary to do deep investigation for the stability and robustness analysis and the design of advanced tracking controllers for second-order linear time-varying systems. It is shown that the design of sliding mode control system is divided into two steps. A linear sliding mode controller is designed first to speed up the error convergence when the error is greater than one. A terminal sliding mode controller is then designed to guarantee that the error can converge to zero in a finite time when the error is around the system origin. In order to have a smooth switching from the linear sliding mode control to the terminal sliding mode control, a fuzzy logic technique.is used to connect two sliding mode surfaces. The stability of the proposed fuzzy sliding mode controller is analyzed, and the convergence and robustness properties are demonstrated in a simulation example with a secondorder system.

A simple robust fuzzy-logic sliding-mode controller of the diagonal type

Intelligent Systems for Manufacturing, 1998

The paper presents a reduced-complexity sliding-mode fuzzy-Iogic controller (RC-SMFLC) of the diagonal type which keeps the system under control on the sliding surface, thus assuring stability of the closed-Ioop system. This controller does not need the prior knowledge of the system or the prior design of the rule base, or the prior selection of the shape of the membership functions. Simulation results obtained for both linear and nonlinear systems showed the excellent performance of the controller.

Design a robust self-tuning fuzzy sliding mode control for second order systems

2012

Robotic systems as second-order systems are essential part in the industry world. Controls of These systems are critical outstanding to a wide range of their application. Robustness and stability are two important demands in any control system. Control of Robot manipulators is challenged because they are multi-input multi-output (MIMO), nonlinear, time variant and have uncertainty. Furthermore, the robot manipulators used in unknown and unstructured situation, so they provide sophisticated systems. Therefore, it is a challenge to design an adaptive nonlinear robust controller, with has had suitable performance (e.g., minimum error, good trajectory, disturbance rejection). Non-classical Control methods used the artificial intelligence theory (e.g., fuzzy logic, neural network, and neuro fuzzy) to reduce the limitation of these types of systems. In This paper by using fuzzy rules and a non-classic method, an adaptive fuzzy sliding mode controller will be presented.

A Simple Robust Sliding-Mode Fuzzy-Logic Controller of the Diagonal Type

Journal of Intelligent and Robotic Systems, 1999

This paper derives and analyzes a new robust fuzzy-logic sliding-mode controller of the diagonal type, which does not need the prior design of the rule base. The basic objective of the controller is to keep the system on the sliding surface so as to ensure the asympotic stability of the closed-loop system. The control law consists of two rules: (i) IF sign(e(t)ė(t)) 0 THEN change the control action, where e(t) = x(t) − xd(t) is the system state error, and the control action can be either an increase or decrease of the control signal, which is realized through the use of fuzzy rules. The proposed controller, which does not need the prior knowledge of the system model and the prior design of the membership functions" shape, was tested, by simulation, on linear and nonlinear systems. The performance was in all cases excellent (very fast trajectory tracking, no chattering) . Of course, as in traditional control, there was a trade-off between the rise-time and the overshoot of the system response.

Design of fuzzy sliding-mode control systems

Fuzzy Sets and Systems, 1998

In this paper the design of fuzzy sliding-mode control is discussed. For a complex physical system represented by an aggregated fuzzy global model which compromises a set of linear models, conditions for the fuzzy sliding mode control to stabilize the global fuzzy model are given. Simulations are presented to show the effectiveness of the control strategy.

Robust Fuzzy Sliding Mode Controller for Discrete Nonlinear Systems

International Journal of Computers Communications & Control, 2008

In this work we are interested to discrete robust fuzzy sliding mode control. The discrete SISO nonlinear uncertain system is presented by the Takgi- Sugeno type fuzzy model state. We recall the principle of the sliding mode control theory then we combine the fuzzy systems with the sliding mode control technique to compute at each sampling time the control law. The control law comports two terms: equivalent control law and switching control law which has a high frequency. The uncertainty is replaced by its upper bound. Inverted pendulum and mass spring dumper are used to check performance of the proposed fuzzy robust sliding mode control scheme.

Sliding Mode Control of Fuzzy Dynamic Systems

2006 9th International Conference on Control, Automation, Robotics and Vision, 2006

In this paper, a sliding mode control scheme is developed for a class of complex nonlinear systems with their T-S fuzzy models. It is shown that a set of extreme fuzzy subsystems are first derived, and a constructive sliding mode control law is then developed to guarantee the stability of the closed-loop fuzzy system. Simulation results are presented in support of the proposed scheme.

Adaptive fuzzy sliding mode control of uncertain nonlinear systems

Saude E Sociedade, 2010

This paper presents a detailed discussion about the convergence properties of a variable structure controller for uncertain single-input-single-output nonlinear systems (SISO). The adopted approach is based on the sliding mode control strategy and enhanced by an adaptive fuzzy algorithm to cope with modeling inaccuracies and external disturbances that can arise. The boundedness of all closed-loop signals and the convergence properties of the tracking error are analytically proven using Lyapunov's direct method and Barbalat's lemma. This result corrects flawed conclusions previously reached in the literature. An application of this adaptive fuzzy sliding mode controller to a second-order nonlinear system is also presented. The obtained numerical results demonstrate the improved control system performance.

Analysis on Advancement of Hybrid Fuzzy Sliding Mode Controllers for Nonlinear Systems

arXiv (Cornell University), 2019

Chattering phenomena is the major problem affecting sliding mode control (SMC). Also, finding a suitable structure and appropriate parameters values of fuzzy logic system (FLS) is a complex and difficult task. In addition, the stability of a general FLS is difficult to guarantee. Many types of combinations between FLS and SMC have been used to form an intelligent and robust controller that deviates from the limitations of each constituent and benefit from the advantages of each constituent. In this study, a survey of recent developments on the Hybridization of FLS (type-1) and SMC is presented. In addition, the differences between using the SMC in FLC or using FLC in SMC as well as their limitation and advantages are highlighted. It is found that the majority of the combinations made are intended to approximate the nonlinear sliding surface within the boundary layer. Limitations of the previous approaches and future research directions are pointed out. For novice researchers, this survey can serve as a foundation for their work while for expert researchers this review can serve as a benchmark for further advancement and exploration of other hybridization methods.

Design and stability analysis of a new sliding-mode fuzzy logic controller of reduced complexity

Machine Intelligence and Robotic Comtrol, vol. 1, no. 1, 27-41, 1999

This paper derives and analyzes a new robust fuzzy-logic sliding-mode controller of diagonal type which does not need prior design of the rule base. The controller was tested by simulation on linear and nonlinear systems. In all cases the performance was proved quite satisfactory (very fast trajectory and no chattering).