scholarly journals Sliding mode controller design for second-order unstable processes with dead-time

2020 ◽  
Vol 71 (4) ◽  
pp. 237-245
Author(s):  
Mohammad Atif Siddiqui ◽  
Md Nishat Anwar ◽  
Shahedul Haque Laskar
Keyword(s):  
Performance Index ◽  
Dead Time ◽  
Sliding Mode ◽  
Search Algorithm ◽  
Optimization Technique ◽  
Second Order ◽  
The Other ◽  
Control Law ◽  
Continuous Control ◽  
Discontinuous Control

AbstractA new approach is proposed to design the sliding mode (SM) controller for the unstable second-order plus dead-time (SOPDT) processes. The sliding mode control consists of two control laws ie continuous control law and discontinuous control law. The continuous control law parameters have been derived in terms of unstable SOPDT process parameters using the root locus technique. On the other hand, the parameters of discontinuous control law are tuned by optimizing a performance index using a recently developed metaheuristic search algorithm, namely the grasshopper optimization technique. The performance index is framed to achieve a good trade-off between performance and control efforts. Finally, simulations are conducted to validate the effectiveness of the proposed approach over the other existing techniques. It is observed that the proposed approach is able to deliver better disturbance rejection, minimal control efforts and good setpoint tracking.

A New Finite Time Control Solution for Robotic Manipulators Based on Nonsingular Fast Terminal Sliding Variables and the Adaptive Super-Twisting Scheme

2019 ◽  
Vol 14 (3) ◽  
Author(s):  
Vo Anh Tuan ◽  
Hee-Jun Kang
Keyword(s):  
Finite Time ◽  
Control Method ◽  
Sliding Mode ◽  
Robotic Manipulators ◽  
Control Law ◽  
Continuous Control ◽  
Terminal Sliding Mode ◽  
Finite Time Convergence ◽  
Position Errors ◽  
Time Control

In this study, a new finite time control method is suggested for robotic manipulators based on nonsingular fast terminal sliding variables and the adaptive super-twisting method. First, to avoid the singularity drawback and achieve the finite time convergence of positional errors with a fast transient response rate, nonsingular fast terminal sliding variables are constructed in the position errors' state space. Next, adaptive tuning laws based on the super-twisting scheme are presented for the switching control law of terminal sliding mode control (TSMC) so that a continuous control law is extended to reject the effects of chattering behavior. Finally, a new finite time control method ensures that sliding motion will take place, regardless of the effects of the perturbations and uncertainties on the robot system. Accordingly, the stabilization and robustness of the suggested control system can be guaranteed with high-precision performance. The robustness issue and the finite time convergence of the suggested system are totally confirmed by the Lyapunov stability principle. In simulation studies, the experimental results exhibit the effectiveness and viability of our proposed scheme for joint position tracking control of a 3DOF PUMA560 robot.

Second Order Sliding Mode Control of Direct-Drive Ring Permanent Magnet Torque Motor

2011 ◽  
Vol 383-390 ◽  
pp. 5964-5971 ◽  
Author(s):  
Yi Biao Sun ◽  
Ya Nan Jing ◽  
Jia Kuan Xia
Keyword(s):  
Sliding Mode Control ◽  
Permanent Magnet ◽  
Sliding Mode ◽  
Servo System ◽  
Second Order ◽  
Continuous Control ◽  
Direct Drive ◽  
Mode Control ◽  
Twisting Algorithm ◽  
Second Order Sliding Mode

The direct-drive ring permanent magnet torque motor is easily affected by parameters changes and the load torque disturbances, which reduces the servo performance of the system. In order to enhance the robustness of the servo system, the super twisting algorithm based on the second order sliding mode control (SMC) is proposed as the speed controller of the direct-drive servo system. The super twisting algorithm need not know the information of the sliding mode time derivative, which through the continuous control measure the sliding mode and its derivative approach zero in finite time. This method not only guarantees the robustness of the servo system and eliminates chatting, but also enhances the static precision of the servo system. The simulation results show that the servo system of the direct-drive NC rotary table has a very strong robustness by adopting the control method against parameters changes and the external disturbances.

Adaptive smooth second-order sliding mode control method with application to missile guidance

2015 ◽  
Vol 39 (6) ◽  
pp. 848-860 ◽  
Author(s):  
Zheng Wang
Keyword(s):  
Sliding Mode Control ◽  
Finite Time ◽  
Control Method ◽  
Sliding Mode ◽  
Second Order ◽  
Control Law ◽  
Smooth Control ◽  
Mode Control ◽  
Control Command ◽  
Second Order Sliding Mode

This paper proposes an adaptive smooth second-order sliding mode control law for a class of uncertain non-linear systems. The key point of this control law is ensuring a smooth control signal considering parametric uncertainty and disturbances with unknown bounds. The proposed control method is obtained by introducing a continuous function under the integral and using adaptive gains. The switching function and its derivative are forced to zero in finite time. This is achieved using a smooth control command and without the prior knowledge of upper bound parameters of uncertainties. The finite-time stability is proved based on a quadratic Lyapunov approach and the reaching time is estimated. This structure is used to create a homing guidance law and the efficiency is evaluated via simulations.

scholarly journals Discrete time reaching law based variable structure control for fast reaching with reduced chattering

2020 ◽  
Vol 9 (1) ◽  
pp. 51
Author(s):  
Pournami Padmalatha ◽  
Susy Thomas
Keyword(s):  
Discrete Time ◽  
Sliding Mode ◽  
Variable Structure Control ◽  
Variable Structure ◽  
The Other ◽  
Control Law ◽  
Sliding Surface ◽  
Structure Control ◽  
Reaching Law ◽  
Speed Up

In this paper, a variable structure control law is proposed for discrete time sliding mode control so as to reduce both reaching time and quasi sliding mode band reduction. This new law is composed of two different sliding variable dynamics; one to achieve fast reaching and the other to counter its effect on widening the quasi sliding mode band. This is accomplished<br />by introducing a boundary layer around the sliding surface about which the transformation of the sliding variable dynamics takes place. This provides the flexibility to choose the initial dynamics in such a way as to speed up the reaching phase and then at the boundary transform this dynamics to one that reduces the quasi sliding mode band. Thus, the law effectively<br />coalesces the advantageous traits of hitherto proposed reaching laws that succeed in either the reduction of reaching phase or the elimination of quasi sliding mode band. The effectiveness of the proposed reaching law is validated through simulations.<br /><br />

Dynamical Adaptive First and Second-Order Sliding Backstepping Control of Nonlinear Nontriangular Uncertain Systems

2000 ◽  
Vol 122 (4) ◽  
pp. 746-752 ◽  
Author(s):  
J. C. Scarratt ◽  
A. Zinober ◽  
R. E. Mills ◽  
Miguel Rios-Bolı´var ◽  
A. Ferrara ◽  
...  
Keyword(s):  
Sliding Mode Control ◽  
Uncertain Systems ◽  
Sliding Mode ◽  
Original System ◽  
Second Order ◽  
Control Law ◽  
Adaptive Backstepping ◽  
Mode Control ◽  
Unmatched Uncertainties

In this paper combined algorithms for the control of nontriangular nonlinear systems with unmatched uncertainties will be presented. The controllers consist of a combination of Dynamical Adaptive Backstepping (DAB) and Sliding Mode Control (SMC) of first and second order. In order to solve a tracking problem, the DAB algorithm (a generalization of the backstepping technique) makes use of virtual functions as well as tuning functions to construct a transformed system for which a regulation problem has to be solved. The new state is extended by an n−ρth order subsystem in canonical form where n is the order of the original system and ρ is the relative degree. The role of the sliding mode control is to replace the last step of the design of the control law to obtain more robustness toward disturbances and unmodeled dynamics. The main advantages of the second-order sliding mode algorithm are the prevention of chattering, higher accuracy, and a significant simplification of the control law. A comparative study of these first and second order sliding controllers will be presented. [S002-0434(00)02604]

Sliding mode control for non-linear systems with global invariance

1997 ◽  
Vol 211 (1) ◽  
pp. 75-82 ◽  
Author(s):  
C-L Chen ◽  
W-Y Lin
Keyword(s):  
Sliding Mode Control ◽  
Sliding Mode ◽  
External Disturbance ◽  
Parametric Uncertainty ◽  
Invariance Property ◽  
Control Law ◽  
Continuous Control ◽  
Mode Control ◽  
Non Linear Systems ◽  
The Cost

In the conventional sliding mode control, a discontinuous control signal is applied to achieve the sliding condition. This control makes the system invariant to parametric uncertainty and external disturbance, but also causes chattering. Modified approaches are introduced to eliminate chattering at the cost of the invariance property or accuracy. This paper describes the use of the concept of extended systems, such that a continuous control is obtained using a sliding mode control design scheme. A sliding surface is assigned so that the sliding mode motion will occur while the proposed control law is applied. This results in a system with global invariance.

A Terminal Sliding Mode Control of Disturbed Nonlinear Second-Order Dynamical Systems

2016 ◽  
Vol 11 (5) ◽  
Author(s):  
Pawel Skruch
Keyword(s):  
Dynamical Systems ◽  
Nonlinear Dynamical Systems ◽  
Sliding Mode ◽  
Second Order ◽  
Control Law ◽  
Sliding Surface ◽  
Terminal Sliding Mode ◽  
Nonlinear Dynamical ◽  
Second Order Differential Equations ◽  
Bounded Disturbance

The paper presents a terminal sliding mode controller for a certain class of disturbed nonlinear dynamical systems. The class of such systems is described by nonlinear second-order differential equations with an unknown and bounded disturbance. A sliding surface is defined by the system state and the desired trajectory. The control law is designed to force the trajectory of the system from any initial condition to the sliding surface within a finite time. The trajectory of the system after reaching the sliding surface remains on it. A computer simulation is included as an example to verify the approach and to demonstrate its effectiveness.

Vibration Control of Redundant Flexible-Joint Manipulators

1997 ◽  
Vol 119 (1) ◽  
pp. 119-125
Author(s):  
Fengfeng Xi
Keyword(s):  
Numerical Simulations ◽  
Vibration Control ◽  
Control Method ◽  
Optimization Technique ◽  
Main Idea ◽  
The Other ◽  
Control Law ◽  
Flexible Joint ◽  
Flexible Joint Manipulator

Presented in this paper is a method for controlling vibrations of a redundant flexible-joint manipulator. The main idea behind this method is to utilize joint redundancy to minimize the change in the manipulator inertia, so that a simple gain-fixed control law can be used to control joint vibrations. For this purpose, two optimal joint trajectory generators are proposed; one is based on the extended Jacobian method and the other is based on an optimization technique. Numerical simulations are provided to demonstrate the effectiveness of the proposed control method.

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