Discrete Time Sliding Mode Control Scheme for Nonlinear Systems With Bounded Uncertainties

2018 ◽  
Vol 7 (2) ◽  
pp. 15-33 ◽  
Author(s):  
Jalel Ghabi ◽  
Ahmed Rhif ◽  
Sundarapandian Vaidyanathan
Keyword(s):  
Sliding Mode Control ◽  
Discrete Time ◽  
Sliding Mode ◽  
System Stability ◽  
Switching Function ◽  
External Disturbances ◽  
Mode Control ◽  
Control Scheme ◽  
Control Methodology ◽  
Discrete Sliding Mode Control

This article introduces a sliding mode controller to stabilize a discrete-time nonlinear system in the presence of uncertainties and external disturbances. The proposed controller is derived to guarantee the existence of a quasi-sliding mode, taking into account the upper bound of uncertainties. With this method, a recursive switching function is used, which allows for recovering lost invariance and robustness properties of a discrete sliding mode control. As for the system stability, it is found that the system is stabilized and finally restricted to a known region. This control scheme ensures robustness against parametric uncertainties and external disturbances as well as the elimination of chattering. In this article, after a detailed formalization of the proposed control design, a numerical example for an inverted pendulum is considered, proving the effectiveness of the control methodology.

Hybrid robust discrete sliding mode control for generalized continuous chaotic systems subject to external disturbances

2018 ◽  
Vol 29 ◽  
pp. 74-84 ◽  
Author(s):  
Jason Sheng-Hong Tsai ◽  
Jiunn-Shiou Fang ◽  
Jun-Juh Yan ◽  
Ming-Cheng Dai ◽  
Shu-Mei Guo ◽  
...  
Keyword(s):  
Sliding Mode Control ◽  
Chaotic Systems ◽  
Sliding Mode ◽  
External Disturbances ◽  
Mode Control ◽  
Discrete Sliding Mode Control

Fuzzy PID Sliding Mode Control for Robotics: An Application to Surgical Robot

2019 ◽  
Vol 12 (2) ◽  
pp. 118-129
Author(s):  
Mohd S. Qureshi ◽  
Pankaj Swarnkar ◽  
Sushma Gupta
Keyword(s):  
Sliding Mode Control ◽  
Sliding Mode ◽  
Robot Manipulator ◽  
Technological Development ◽  
Minimal Invasive ◽  
Surgical Robot ◽  
System Stability ◽  
Surgical Robots ◽  
Mode Control ◽  
Control Methodology

Background: Continually in view of the fact that digital technology entered in the Operating Theatre (OT), surgery has moved out through one of the big revolutions in medical field. Robotic-Assisted Surgery (RAS) is a way of technological development in the medical environment, designed to thrash the limitations of Minimal Invasive Surgery (MIS). Surgical robots carry out operation with the motion control of manipulator joints on the patient. Precise and fine control of these robots is very imperative. Methods: The paper depicts the control methodology for surgical robots based on the combination of Sliding Mode Control (SMC) with Fuzzy Logic Control (FLC). The destructive chattering phenomenon in SMC is circumvented by espousing FLC in SMC. System stability is investigated using Lyapunov theorem. All numerical simulations have been carried out using MATLAB tool for 2 DOF robot manipulator formulated for trajectory tracking process which shows the efficacy of the proposed methodology. Results: The simulation results of FSMC are compared with the conventional SMC which represents the improvement of control law for the attainment of optimized results. Conclusion: The proposed methodology in the paper is very much suitable in controlling surgical robot during typical surgical operations. The effectiveness of proposed control methodology is shown using simulation studies in the paper.

A Variable-Gain Discrete Sliding Mode Control Strategy With PID-Type Sliding Surface for an Ultra-Precision Wafer Stage

2016 ◽  
Author(s):  
Min Li ◽  
Yu Zhu ◽  
Kaiming Yang ◽  
Chuxiong Hu ◽  
Haihua Mu
Keyword(s):  
Sliding Mode Control ◽  
Sliding Mode ◽  
Frequency Noise ◽  
Main Concern ◽  
Sliding Surface ◽  
External Disturbances ◽  
Variable Gain ◽  
Mode Control ◽  
Ultra Precision ◽  
Discrete Sliding Mode Control

The ultra-precision wafer stage is an important mechatronic unit in a wafer scanner for manufacturing integrated circuits while its motion control is still the main concern. To overcome the performance-limiting trade-offs of fixed-gain discrete sliding mode control (DSMC), a novel variable-gain DSMC strategy with PID-type sliding surface is proposed for an ultra-precision wafer stage. Specially, PID-type sliding surface is employed to avoid the steady-state error induced by external disturbances. Via the exponential reaching law approach, DSMC with PID-type sliding surface is synthesized. Variable-gain control methodology is newly introduced into DSMC, and the control gain varies with the trajectory phase that the wafer stage is in and the tracking error magnitude. Performance assessment on a developed wafer stage validates that with nano-scale tracking accuracy the proposed strategy not only improves the low-frequency tracking ability without the amplification of high-frequency noise, but also possesses the excellent robustness to external disturbances.

Sensor faults tolerance control for a novel multi-rotor aircraft based on sliding mode control

2017 ◽  
Vol 233 (1) ◽  
pp. 180-196 ◽  
Author(s):  
Chunyang Fu ◽  
Yantao Tian ◽  
Cheng Peng ◽  
Xun Gong ◽  
Lei Zhang ◽  
...  
Keyword(s):  
Angular Velocity ◽  
Sliding Mode Control ◽  
Sliding Mode ◽  
Lyapunov Theory ◽  
System Stability ◽  
Sensor Faults ◽  
External Disturbances ◽  
Outer Loop ◽  
Velocity Sensor ◽  
Mode Control

This paper deals with the controllers design using a novel siding mode control and proportional–derivative control for the trajectory tracking problem of a new multi-rotor aircraft, which experiences angular velocity sensor faults and external disturbances. The control system is divided into two parts: the inner loop for attitude subsystem and outer loop for position subsystem. For the inner loop, the angular velocity sensor faults, including bias, drift, loss of accuracy, and loss of effectiveness are considered as equivalent mismatched disturbances, while the system internal coupling, nonlinearity, and external disturbances are considered as equivalent matched disturbances. A novel sliding mode control approach is proposed for inner loop controller design, which includes a nonlinear disturbance observer to estimate both mismatched and matched disturbances, a novel switching surface based on the estimation of the mismatched disturbance to counteract its impact, a double power reaching law to attenuate the chattering problem, and a compensation for the matched disturbance to reduce the controller gains. The sensor faults are handled without fault detection and controller reconfiguration, making the method require less computation and easy implementation. The proposed method enhances the robustness without sacrificing the nominal properties. For outer loop, the proportional–derivative approach is used to design the virtual controller. The closed-loop system stability is proved by the Lyapunov theory. Finally, various simulation experiments are shown to validate the effectiveness, robustness, and the superiority of the proposed flight control scheme.

Discrete Sliding Mode Control Design With Invariant Sliding Sectors

2000 ◽  
Vol 122 (4) ◽  
pp. 776-782 ◽  
Author(s):  
Xinghuo Yu ◽  
Shuanghe Yu
Keyword(s):  
Sliding Mode Control ◽  
Control Systems ◽  
Discrete Time ◽  
Sliding Mode ◽  
Design Procedure ◽  
Control Design ◽  
Higher Order ◽  
Mode Control ◽  
Simulation Results ◽  
Discrete Sliding Mode Control

In this paper, a new concept of invariant sliding sector is proposed for the design of discrete time sliding mode control. A methodology is developed which ensures the existence of the invariant sliding sector and conditions to guarantee the existence of the invariant sliding sector are derived. The second-order discrete sliding mode control systems are used to inform the discussion. Simulation results are presented to demonstrate the usefulness of the concept and effectiveness of the methodology proposed. It should be noted that most of the design procedure could be extended to higher order discrete sliding mode control systems. [S0022-0434(00)02004-9]

Robust predictive sliding mode control for input rate-constrained discrete-time system

2018 ◽  
Vol 36 (3) ◽  
pp. 901-919 ◽  
Author(s):  
Rong Li ◽  
Qingxian Wu
Keyword(s):  
Sliding Mode Control ◽  
Discrete Time ◽  
Sliding Mode ◽  
Input Rate ◽  
Discrete Time System ◽  
Control Approach ◽  
Mode Control ◽  
Discrete Time Systems ◽  
Control Scheme ◽  
Time Systems

Abstract This paper investigates a class of uncertain linear discrete-time systems subject to input rate saturation. A predictive sliding mode control approach is proposed which guarantees the control inputs remain bounded in the input rate saturation. Furthermore, the disturbance observer is developed to compensate for the system uncertainty and disturbance. Finally, the simulations demonstrate the effectiveness of the proposed predictive sliding mode control scheme.

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