scholarly journals Improved Model-Free Sliding Mode Control Algorithm for Control Non-Linear Systems

2020 ◽  
Vol 27 (4) ◽  
pp. 79-89
Author(s):  
Hasnaa Wasouf ◽  
Jomana Diab
Keyword(s):  
Sliding Mode Control ◽  
Control Algorithm ◽  
Sliding Mode ◽  
Control Signal ◽  
Direct Lyapunov Method ◽  
Mode Control ◽  
Model Free ◽  
Non Linear ◽  
The Stability ◽  
Non Linear System

When testing the performance of the model-free sliding mode control algorithm, it was found that it could not maintain good performance when the system was exposed to noise. this research suggests designing a noise-resistant model-free sliding mode control algorithm. The importance of this algorithm is that it takes into account the effect of the noise, where the noise value is implemented in the model-free algorithm. The sliding surface of the controller is designed based on the improved relationship and to ensure the stability of the system in the closed-loop the control signal was derived based on the direct Lyapunov method. To minimize the effects of chattering in the control signal, the control law was reconfigured using a boundary layer. The improved algorithm was implemented to a second-order non-linear system and the simulation results showed the system's ability to track the desired signal in spite of the presence of the noise as well as its ability to maintain the stability of the controlled system

scholarly journals The Control Algorithm and Experimentation of Coaxial Rotor Aircraft Trajectory Tracking Based on Backstepping Sliding Mode

Aerospace ◽  
2021 ◽  
Vol 8 (11) ◽  
pp. 337
Author(s):  
Jiulong Xu ◽  
Yongping Hao ◽  
Junjie Wang ◽  
Lun Li
Keyword(s):  
Sliding Mode Control ◽  
Trajectory Tracking ◽  
Control Algorithm ◽  
Sliding Mode ◽  
Model Parameters ◽  
External Interference ◽  
Mode Control ◽  
Coaxial Rotor ◽  
Non Linear ◽  
Backstepping Sliding Mode Control

In view of the uncertainty of model parameters, the influence of external disturbances and sensor noise on the flight of coaxial rotor aircraft during autonomous flight, a robust backstepping sliding mode control algorithm for the position and attitude feedback control system is studied to solve the trajectory tracking problem of an aircraft in the case of unknown external interference. In this study, a non-linear dynamic model based on a disturbed coaxial rotor aircraft was established for an unknown flight. Then, a non-linear robust backstepping sliding mode controller was designed, which was divided into two sub-controllers: the attitude controller and the position controller of the coaxial rotor aircraft. In the controller, virtual control was introduced to construct the Lyapunov function to ensure the stability of each subsystem. The effectiveness of the proposed controller was verified through numerical simulation. Finally, the effectiveness of the backstepping sliding mode control algorithm was verified by flight experiments.

scholarly journals Efficient Control of a Non-Linear System Using a Modified Sliding Mode Control

2019 ◽  
Vol 9 (7) ◽  
pp. 1284 ◽  
Author(s):  
Saad Abbasi ◽  
Karam Kallu ◽  
Min Lee
Keyword(s):  
Sliding Mode Control ◽  
Sliding Mode ◽  
Robot Manipulator ◽  
Sliding Surface ◽  
Parameter Uncertainties ◽  
Pass Filter ◽  
Mode Control ◽  
Efficient Control ◽  
Non Linear ◽  
Non Linear System

Trajectory tracking is an essential requirement in robot manipulator movement and localization applications. It is a current research topic of interest, and several researchers have proposed different schemes to achieve the task accurately. This research proposes efficient control of a hydraulic non-linear robot manipulator using a modified sliding mode control, named proportional derivative sliding mode control with sliding perturbation observer (PDSMCSPO), to overcome parameter uncertainties and non-linearity. The proposed new control strategy achieves higher accuracy and better time convergence than the previous one. A positive derivative gain, which has a value less than one, is multiplied with the velocity error term of the sliding surface. The proposed control (PDSMCSPO) also achieves robustness. Results show that by introducing the derivative gain, the chattering from the system has been reduced more than classical sliding mode control (SMC). The reason is that during reaching phase this small gain multiplies with the perturbation and minimizes the effect of perturbation on the system. A smaller value of switching gain K is required as compared to SMC, and the transfer function between sliding surface and perturbation in proportional derivative sliding mode control (PDSMC)has low pass filter characteristics. The proposed PDSMCSPO has a faster response than previous sliding mode control with sliding perturbation observer (SMCSPO), and the output and sliding surface convergence to the desired value is much quicker than conventional logic. Some other characteristics such as error in the output are small because of more attenuation of the perturbation signal. Simulation and experimental results are presented for a link between the hydraulic robot manipulator and the mass damper system.

scholarly journals Neural Network PID Algorithm for a Class of Discrete-Time Nonlinear Systems

2018 ◽  
Vol 14 (02) ◽  
pp. 103 ◽  
Author(s):  
Huifang Kong ◽  
Yao Fang
Keyword(s):  
Neural Network ◽  
Nonlinear System ◽  
Sliding Mode Control ◽  
Discrete Time ◽  
Control Algorithm ◽  
Sliding Mode ◽  
Model Parameters ◽  
Pid Algorithm ◽  
Mode Control ◽  
Model Free

<p class="0abstract"><span lang="EN-US">The control of nonlinear system is the hotspot in the control field. The paper proposes an algorithm to solve the tracking and robustness problem for the discrete-time nonlinear system. The completed control algorithm contains three parts. First, the dynamic linearization model of nonlinear system is designed based on Model Free Adaptive Control, whose model parameters are calculated by the input and output data</span><span lang="EN-US"> of system</span><span lang="EN-US">. Second, the model error is estimated using the Quasi-sliding mode control algorithm</span><span lang="EN-US">, hence, the whole model of system is estimated</span><span lang="EN-US">. Finally, the neural network </span><span lang="EN-US">PID </span><span lang="EN-US">controller is designed to get the optimal control law. The convergence and BIBO stability of the control system is proved by the Lyapunov function. The simulation results </span><span lang="EN-US">in</span><span lang="EN-US"> the </span><span lang="EN-US">linear and </span><span lang="EN-US">nonlinear system validate the effectiveness and robustness of the algorithm.</span><span lang="EN-US"> The robustness </span><span lang="EN-US">effort </span><span lang="EN-US">of </span><span lang="EN-US">Quasi-sliding mode control algorithm</span><span lang="EN-US"> in nonlinear system is also verified in the paper.</span></p>

Design of an adaptive chattering avoidance global sliding mode tracker for uncertain non-linear time-varying systems

2016 ◽  
Vol 39 (10) ◽  
pp. 1547-1558 ◽  
Author(s):  
Saleh Mobayen ◽  
Fairouz Tchier
Keyword(s):  
Sliding Mode Control ◽  
Tracking Control ◽  
Sliding Mode ◽  
Linear Time ◽  
Time Varying ◽  
Mode Control ◽  
Global Sliding Mode Control ◽  
Non Linear ◽  
Time Varying Systems ◽  
Non Linear System

In this paper, a novel adaptive global sliding mode control technique is suggested for the tracking control of uncertain and non-linear time-varying systems. The proposed scheme composed of a global sliding mode control structure to eliminate reaching mode and an adaptive tracker to construct the auxiliary control term for eliminating the impacts of unwanted perturbations. Using the Lyapunov direct method, the tracking control of the non-linear system is guaranteed. Moreover, superior position tracking performance is obtained, the control effort is considerably decreased and the chattering phenomenon is removed. Furthermore, using adaptation laws, information about the upper bounds of the system perturbations is not required. To indicate the effectiveness of the suggested scheme, three simulation examples are presented. Simulation results demonstrate the superiority and capability of the offered control law to improve the transient performance of a closed-loop system using online adaptive parameters.

A Novel Exoskeleton with Fractional Sliding Mode Control for Upper Limb Rehabilitation

Robotica ◽  
2020 ◽  
Vol 38 (11) ◽  
pp. 2099-2120 ◽  
Author(s):  
Md Rasedul Islam ◽  
Mehran Rahmani ◽  
Mohammad Habibur Rahman
Keyword(s):  
Sliding Mode Control ◽  
Upper Limb ◽  
Control Algorithm ◽  
Sliding Mode ◽  
Lyapunov Theory ◽  
Upper Limb Rehabilitation ◽  
Mode Control ◽  
Wide Range ◽  
The Stability ◽  
Limb Rehabilitation

SUMMARYThe robotic intervention has great potential in the rehabilitation of post-stroke patients to regain their lost mobility. In this paper, firstly, we present a design of a novel, 7 degree-of-freedom (DOF) upper limb robotic exoskeleton (u-Rob) that features shoulder scapulohumeral rhythm with a wide range of motions (ROM) compared to other existing exoskeletons. An ergonomic shoulder mechanism with two passive DOF was included in the proposed exoskeleton to provide scapulohumeral motion with corresponding full ROM. Also, the joints of u-Rob have more range of motions compared to its existing counterparts. Secondly, we propose a fractional sliding mode control (FSMC) to control u-Rob. Applying the Lyapunov theory to the proposed control algorithm, we showed the stability of it. To control u-Rob, FSMC has shown effectiveness to handle unmodeled dynamics (e.g. friction, disturbance, etc.) in terms of better tracking and chatter compared to traditional SMC.

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