Design of Sliding Mode Control Based on Nonlinear Observer for Nonlinear System

2011 ◽  
Vol 109 ◽  
pp. 541-546 ◽  
Author(s):  
Hui Da Duan ◽  
Yan Tao Tian ◽  
De Jun Liu

A new sliding mode controller for trajectory tracking of ball and plate system is proposed. In the controller, a nonlinear observer which is independent on plant model is used to observer the uncertainties and disturbance of the system. This paper proved that the nonlinear observer is convergence by properly selecting the parameters of observer. Sliding mode controller based on nonlinear observer is designed for the ball and plate system and it can guarantee stabilization of closed-loop system. The results of simulation and experiments indicate that the proposed nonlinear observer can observer uncertainties and disturbance of system, the proposed sliding mode control method is effectively to solve the problems of trajectory tracking in the nonlinear ,uncertain system.

2017 ◽  
Vol 40 (7) ◽  
pp. 2227-2239 ◽  
Author(s):  
Haoping Wang ◽  
Qiankun Qu ◽  
Yang Tian

In this paper, a nonlinear observer based sliding mode control (NOSMC) approach for air-path and a model-based observer for oxygen concentration in the diesel engine equipped with a variable geometry turbocharger and exhaust gas recirculation is introduced. We propose a less conservative observer design technique for Lipschitz nonlinear systems using Ricatti equations. The observer gains are obtained by solving the linear matrix inequality (LMI). Then a robust nonlinear control method, sliding mode control is applied for the states of intake and exhaust manifold pressure and compressor mass flow rate for the sake of the minimization of emissions. The proposed NOSMC controller is applied on a mean value model of turbocharged diesel engine. Besides this, a model-based observer is developed to estimate the oxygen concentration in the intake and exhaust manifolds owing to its significance in reducing emissions of diesel engines. The validation and efficiency of the proposed method are demonstrated by AMESim and Matlab/Simulink co-simulation results.


2020 ◽  
Vol 26 (17-18) ◽  
pp. 1425-1434 ◽  
Author(s):  
Sunhua Huang ◽  
Jie Wang

In this study, a fractional-order sliding mode controller is effectively proposed to stabilize a nonlinear power system in a fixed time. State trajectories of a nonlinear power system show nonlinear behaviors on the angle and frequency of the generator, phase angle, and magnitude of the load voltage, which would seriously affect the safe and stable operation of the power grid. Therefore, fractional calculus is applied to design a fractional-order sliding mode controller which can effectively suppress the inherent chattering phenomenon in sliding mode control to make the nonlinear power system converge to the equilibrium point in a fixed time based on the fixed-time stability theory. Compared with the finite-time control method, the convergence time of the proposed fixed-time fractional-order sliding mode controller is not dependent on the initial conditions and can be exactly evaluated, thus overcoming the shortcomings of the finite-time control method. Finally, superior performances of the fractional-order sliding mode controller are effectively verified by comparing with the existing finite-time control methods and integral order sliding mode control through numerical simulations.


2013 ◽  
Vol 347-350 ◽  
pp. 302-306 ◽  
Author(s):  
Ji Chen Li ◽  
Feng Qi Gao ◽  
Guang Long Wang ◽  
Ming Wang ◽  
Wen Jie Zhu ◽  
...  

Novel reaching law to nonsingular terminal sliding mode control for the control of the second order nonlinear uncertain system is introduced in this paper. The problems of singularity, chattering and slow convergence of the terminal sliding mode control, and verify the stability of the new controller is analyzed. Due to the premise of eliminating the singular value in the nonsingular terminal sliding mode control, the new reaching law based on the power reaching law enables the finite time convergence of the system equilibrium. By applying the new controller to the inverted pendulum system, the sliding surface had been proved fast and the system chattering had been reduced at the same time. Simulation results indict that the system converges to the equilibrium in a short time and the proposed method is feasible and effective.


2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Gangfeng Yan

Purpose The purpose of this paper is to achieve high-precision sliding mode control without chattering; the control parameters are easy to adjust, and the entire controller is easy to use in engineering practice. Design/methodology/approach Using double sliding mode surfaces, the gain of the control signal can be adjusted adaptively according to the error signal. A kind of sliding mode controller without chattering is designed and applied to the control of ultrasonic motors. Findings The results show that for a position signal with a tracking amplitude of 35 mm, the traditional sliding mode control method has a maximum tracking error of 0.3326 mm under the premise of small chattering; the boundary layer sliding mode control method has a maximum tracking error of 0.3927 mm without chattering, and the maximum tracking error of continuous switching adaptive sliding mode control is 0.1589 mm, and there is no chattering. Under the same control parameters, after adding a load of 0.5 kg, the maximum tracking errors of the traditional sliding mode control method, the boundary layer sliding mode control method and the continuous switching adaptive sliding mode control are 0.4292 mm, 0.5111 mm and 0.1848 mm, respectively. Originality/value The proposed method not only switches continuously, but also the amplitude of the switching signal is adaptive, while maintaining the robustness of the conventional sliding mode control method, which has strong engineering application value.


2018 ◽  
Vol 2018 ◽  
pp. 1-19 ◽  
Author(s):  
Jianguo Guo ◽  
Hao Zhang ◽  
Xiaodong Lu ◽  
Jun Zhou

In this paper, a new adaptive sliding mode control method is presented for the longitudinal model of a generic hypersonic vehicle subject to uncertainties and external disturbance. Firstly, an oriented-control model with mismatched uncertainties is built for a generic hypersonic vehicle. Secondly, the back-stepping technique is introduced to design a sliding mode controller with an adaptive law to adapt to the disturbance and uncertainty. Thirdly, a set of nonlinear disturbance observers are designed to estimate the lumped disturbance and compensate the sliding mode controller, and the stability of the proposed controller is analyzed by utilizing Lyapunov stability theory. Finally, simulation results show that the effectiveness of the proposed controller is validated by the nonlinear model and the proposed method exhibits promising robustness to mismatched uncertainties.


2011 ◽  
Vol 378-379 ◽  
pp. 521-524
Author(s):  
Li Ping Fan ◽  
Ying Song ◽  
Jun Zhang

Bioprocesses have high nonlinearity and parameter uncertainty. In view of these specific natures of the bioreactor, system identification method was firstly used to linearize the nonlinear system and simplify the model of the biological reactor; then a new sliding mode controller with adaptive reaching law is designed for the reactor. The control method can not only analysis the sliding mode movement near or along the switching surface, but also design the dynamic process in trending segments of the system effectively, thus ensure good movement quality in the entire state space. Simulation results prove that the sliding mode control with adaptive reaching law can improve the control performance with negligible chattering and enhanced robustness.


2005 ◽  
Vol 11 (7) ◽  
pp. 903-922 ◽  
Author(s):  
Nurkan Yagiz ◽  
Yuksel Hacioglu

In this paper, we develop a new control method that brings together the advantages of fuzzy logic and sliding mode control. First, we introduce a non-chattering robust sliding mode control. Then, in order to improve the performance of the controller a fuzzy logic algorithm is integrated with the sliding mode controller. This algorithm decides the slope of the sliding surface of the sliding mode controller dynamically. Thus, the system is caught on the sliding surface rapidly and remains over it, more successfully improving the performance of the controller. Afterwards, to test the success of the controller introduced, it is applied to a planar robot, which is to follow a certain trajectory only using the control inputs produced. The results are compared with those of a conventional PID controlled system and a sliding mode controller with constant surface slope. In order to check the robust behavior of the controller designed, an unexpected change in the mass of the second link is introduced and to make the conditions tougher it is assumed that this change is not sensed by the controllers. Noise resistance of the proposed controller is also checked by introducing normally distributed noise components into the equations of motion of the robot model.


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