scholarly journals A Chattering Free Discrete-Time Global Sliding Mode Controller for Optoelectronic Tracking System

2013 ◽  
Vol 2013 ◽  
pp. 1-8 ◽  
Author(s):  
Yan Ren ◽  
Zhenghua Liu ◽  
Xiaodong Liu ◽  
Yu Zhang
Keyword(s):  
Discrete Time ◽  
High Frequency ◽  
Sliding Mode ◽  
Tracking System ◽  
Tracking Error ◽  
Switching Function ◽  
Sliding Mode Controller ◽  
Control Input ◽  
Reaching Law ◽  
Chattering Free

Aiming at the uncertainties including parameter variations and external disturbances in optoelectronic tracking system, a discrete-time global sliding mode controller (DGSMC) is proposed. By the design of nonlinear switching function, the initial state of control system is set on the switching surface. An adaptive discrete-time reaching law is introduced to suppress the high-frequency chattering at control input, and a linear extrapolation method is employed to estimate the unknown uncertainties and commands. The global reachability for sliding mode and the chattering-free property are proven by means of mathematical derivation. Numerical simulation presents that the proposed DGSMC scheme not only ensures strong robustness against system uncertainties and small tracking error, but also suppresses the high-frequency chattering at control input effectively, compared with the SMC scheme using conventional discrete-time reaching law.

DESIGN AND ANALYSIS OF SUPER TWISTING SLIDING MODE CONTROL FOR MACHINE TOOLS

2016 ◽  
Vol 78 (10-3) ◽  
Author(s):  
Chiew Tsung Heng ◽  
Zamberi Jamaludin ◽  
Ahmad Yusairi Bani Hashim ◽  
Nur Aidawaty Rafan ◽  
Lokman Abdullah ◽  
...  
Keyword(s):  
Machine Tools ◽  
Sliding Mode ◽  
Tracking Error ◽  
Control Algorithms ◽  
Sliding Mode Controller ◽  
Control Input ◽  
Positioning System ◽  
Direct Drive ◽  
Chattering Effect

High demands of precision on machine tools are hardly cope by using existing classic control algorithms. This paper focuses on the design, analysis and validation of a super twisting sliding mode controller on a single axis direct drive positioning system for improved tracking performances. The second order positioning system parameters were determined using input and output of measured data. Effects of two gain parameters in control algorithm on the quality of the control input and tracking error were analysed experimentally. The gain parameters were selected based on magnitude reduction in chattering during practical application. The performance of tuned super twisting sliding mode controller was compared with a traditional sliding mode controller using sigmoid-like function. Results showed that super twisting sliding mode controller reduced the chattering effect and improved the performance of system in terms of tracking error by 16.5%.  

Research on Control by Sliding Form of Variable Structure in Follow-Up System

2014 ◽  
Vol 602-605 ◽  
pp. 1099-1102
Author(s):  
Na Fang ◽  
Han Lin Huang ◽  
Feng Li ◽  
Zhi Min Deng
Keyword(s):  
Discrete Time ◽  
Sliding Mode ◽  
Variable Structure ◽  
Sliding Mode Controller ◽  
Simulation Test ◽  
Reaching Law ◽  
Load Disturbance ◽  
Control Criteria ◽  
Parameter Robustness

The article designs a discrete-time sliding mode controller based on reaching law according to the follow-up system’s largely changed loads and strict control criteria for the position. It analyzes the different results by comparison of PID and sliding form of variable structures. Various results from simulation test shows that the control by sliding form of variable structures has better ability to guard load disturbance and parameter robustness.

A chattering-free fuzzy hybrid sliding mode control of an electrohydraulic active suspension

2016 ◽  
Vol 40 (1) ◽  
pp. 222-238 ◽  
Author(s):  
Bassel Shaer ◽  
Jean-Pierre Kenné ◽  
Claude Kaddissi ◽  
Charles Fallaha
Keyword(s):  
Sliding Mode ◽  
Vertical Motion ◽  
Active Suspension ◽  
Switching Function ◽  
Sliding Mode Controller ◽  
Hybrid Controller ◽  
Controller Performance ◽  
Low Pass ◽  
Chattering Free ◽  
Exponential Reaching Law

This paper introduces a new hybrid controller for position and force control of an electrohydraulic car active suspension. In most hybrid controllers, a switching function is normally used in order to take advantage of two separate controllers. Switching between the two controllers produces a chattering in the system, in addition to the chattering that may be inherent to the controller itself, which deteriorates the system performance. In this work, we resolved the switching limitations dilemma by transitioning from one controller to another through two low-pass filters. These filters are used with variable gains to improve the new hybrid position/force controller performance that we developed. The produced control signal is a structured combination, in which the signal coming from the position controller reduces the effect of road perturbations on passengers by bringing the car’s vertical motion to zero. Simultaneously, the signal from the force controller tracks a reference force and thus reduces the force transmitted to passengers. To eliminate the chattering that is inherent to the sliding mode controller, we introduced an exponential reaching law function to the hybrid sliding mode controller. This exponential function also reduced the response time, consequently speeding up the system reaction to suppress perturbations. In addition to that, a recent sliding surface-based controller is applied to vary the filters’ gains and obtain better performance. The frequency analysis is done to verify the controller performance. The proposed hybrid controller is also validated in real time on active suspension workbench and compared with a classical PID controller.

scholarly journals Sensor less control of PMSM fed from three phase four switch inverter based on back EMF observer and sliding mode controller with fast reaching law

2018 ◽  
Vol 7 (2) ◽  
pp. 725
Author(s):  
Ashok kumar R ◽  
Balaji K
Keyword(s):  
Sliding Mode ◽  
Permanent Magnet Synchronous Motor ◽  
Control Technique ◽  
Switching Function ◽  
Sliding Mode Controller ◽  
Position Sensor ◽  
Loop Control ◽  
Reaching Law ◽  
Three Phase ◽  
Speed Regulator

Closed Loop control of PMSM drives require rotor position and angular velocity information, the use of position sensor increases cost of the drive and increases complexity in motor construction. A position sensor less vector control technique is proposed where a back EMF observer is used to estimate motors speed and position signal. Back EMF observer method is simple and has high accuracy in estimating speed of PMSM motor. Permanent magnet synchronous motor is fed from a three-phase four-switch inverter and sliding mode controller is used as a speed regulator. Fast reaching law is added to sliding mode speed controller, which replaces constant switching gain function by variable switching function based on sliding surface. Variable switching function for SMC eliminates the chattering problem that occurs due to high value of constant switching gain. The proposed reaching law for sliding mode controller reduces the time taken for the controller to reach convergence and also increases robustness of the drive during parameter variation and full load conditions. Use of sensor less control technique and four-switch inverter reduced the overall cost of the drive whilst maintaining the performance of the system. Merits of pro-posed sensor less control technique and sliding mode controller with fast reaching law is verified by simulations using MATLAB/Simulink software.

Minimum Tracking Error Control of Flexible Ball Screw Drives Using a Discrete-Time Sliding Mode Controller

2009 ◽  
Vol 131 (5) ◽  
Author(s):  
Chinedum Okwudire ◽  
Yusuf Altintas
Keyword(s):  
Discrete Time ◽  
Error Control ◽  
Sliding Mode ◽  
Tracking Error ◽  
Open Loop ◽  
Ball Screw ◽  
Sliding Mode Controller ◽  
Tracking Accuracy ◽  
Ball Screw Drives ◽  
Tracking Error Control

This paper presents modeling, identification, and discrete-time sliding mode control of ball screw drives with structural flexibility. The mechanical system of the drive is modeled by a two degree-of-freedom system dominated by the coupled longitudinal and torsional dynamics of the drive assembly whose parameters are identified. A mode-compensating disturbance adaptive discrete-time sliding mode controller is then designed to actively suppress the vibrations of the drive. However, it is shown theoretically that, without using minimum tracking error filters, the tracking errors of the drive do not go to zero when sliding mode is reached. Therefore, a method for designing stable and robust minimum tracking error filters, irrespective of the identified open-loop behavior of the drive is proposed. The identification and control of flexible ball screw drives are experimentally tested, and the tracking accuracy of the drives is shown to improve considerably as a result of the designed minimum tracking error filters.

scholarly journals A Novel Fuzzy Sliding-Mode Control for Discrete-Time Uncertain System

2016 ◽  
Vol 2016 ◽  
pp. 1-9 ◽  
Author(s):  
T. H. Yan ◽  
B. Wu ◽  
B. He ◽  
W. H. Li ◽  
R. B. Wang
Keyword(s):  
Fuzzy Logic ◽  
Sliding Mode Control ◽  
Discrete Time ◽  
Sliding Mode ◽  
Dynamic Performance ◽  
Uncertain System ◽  
Sliding Mode Controller ◽  
Reaching Law ◽  
Mode Control ◽  
Dynamic Performances

This paper considers the sliding-mode control problem for discrete-time uncertain systems. It begins by presenting a discrete variable speed reaching law and a discrete-time sliding-mode controller (DSMC) designed using the proposed reaching law, followed by an analysis of their stability and dynamic performance. A sliding-mode controller with simple fuzzy logic is then proposed to further strengthen the dynamic performance of the proposed sliding-mode controller. Finally, the presented DSMC and the DSMC with fuzzy control for adjusting the parameters in this paper are compared with one of the previous proposed classic DSMC systems. The results of this simulation show that the DSMC presented here can suppress chatter and ensure good dynamic performances when fuzzy logic is used to tune the parameters.

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