scholarly journals Terminal Sliding Mode Control with a Novel Reaching Law and Sliding Mode Disturbance Observer for Inertial Stabilization Imaging Sensor

Sensors ◽  
2020 ◽  
Vol 20 (11) ◽  
pp. 3107
Author(s):  
Xin Che ◽  
Dapeng Tian ◽  
Ping Jia ◽  
Yang Gao ◽  
Yan Ren
Keyword(s):  
High Performance ◽  
Sliding Mode ◽  
State Variables ◽  
Terminal Sliding Mode ◽  
Reaching Law ◽  
Gain Term ◽  
Sliding Mode Disturbance Observer ◽  
Exponential Reaching Law ◽  
Imaging Sensors ◽  
Imaging Sensor

High-performance control of inertial stabilization imaging sensors (ISISs) is always challenging because of the complex nonlinearities induced by friction, mass imbalance, and external disturbances. To overcome this problem, a terminal sliding mode controller (TSMC) based on a novel exponential reaching law (NERL) method with a high-order terminal sliding mode observer (HOTSMO) is suggested. First, the TSMC based on NERL is adopted to improve system performance. The NERL incorporates the power term and switching gain term of the system state variables into the conventional exponential reaching law, and the convergent speed of the TSMC is accelerated. Then, an HOTSMO is designed, which considers the speed and lumped disturbances of the system as the observation object. The estimated disturbance is then provided as a compensation for the controller, which enhances the disturbance rejection ability of the system. Comparative simulation and experimental results show that the proposed method achieves the best tracking performance and the strongest robustness than PID and the traditional TSMC methods.

scholarly journals Nonsingular Terminal Sliding Mode Control of PMSM Based on Improved Exponential Reaching Law

Electronics ◽  
2021 ◽  
Vol 10 (15) ◽  
pp. 1776
Author(s):  
Changhong Jiang ◽  
Qiming Wang ◽  
Zonghao Li ◽  
Niaona Zhang ◽  
Haitao Ding
Keyword(s):  
Sliding Mode Control ◽  
Permanent Magnet ◽  
Sliding Mode ◽  
Permanent Magnet Synchronous Motor ◽  
Terminal Sliding Mode Control ◽  
Terminal Sliding Mode ◽  
Reaching Law ◽  
Mode Control ◽  
Nonsingular Terminal Sliding Mode ◽  
Exponential Reaching Law

When a permanent magnet synchronous motor runs at low speed, the inverter will output discontinuous current and generate torque ripple; when the motor is runs at high speed, a large amount of stator harmonic current generates, which affects its speed following ability and torque stability. To ensure the fast and smooth switching of a permanent magnet synchronous motor in the full speed domain, this paper proposes the nonsingular terminal sliding mode control of PMSM speed control based on the improved exponential reaching law. Firstly, the improved exponential reaching law is composed of the state variables and power terms of the sliding mode surface functions. The reaching law function is designed in sections to balance the fast dynamic response of the system and chattering control. Secondly, an improved exponential reaching law based on the sliding mode control strategy of the PMSM speed loop is proposed. By designing the initial value of the integral term in the nonsingular terminal sliding mode surface function, the initial state of the system is located on the sliding mode surface. The integral sliding mode surface is used to reduce the system steady-state error, while the proposed sliding mode reaching law is used to increase the arrival speed and suppress system chattering, ultimately affecting modeling error problems, complex working conditions, and uncertainty factors. This paper proposes a sliding mode observer based on an improved exponential reaching law to compensate for the disturbances. Lyapunov stability theory can prove that this system can make the speed tracking error converge to zero in finite time. Hardware-in-the-loop experiments were used to validate the effectiveness of the proposed method.

A nonsingular fast terminal sliding mode control with an exponential reaching law for robot manipulators

2018 ◽  
Vol 233 (5) ◽  
pp. 1575-1587 ◽  
Author(s):  
Liyin Zhang ◽  
Yuxin Su ◽  
Haihong Wang
Keyword(s):  
Sliding Mode Control ◽  
Finite Time ◽  
Sliding Mode ◽  
Robot Manipulators ◽  
Terminal Sliding Mode Control ◽  
Terminal Sliding Mode ◽  
Reaching Law ◽  
Mode Control ◽  
Fast Terminal Sliding Mode ◽  
Exponential Reaching Law

This paper presents an improved robust tracking control for uncertain robot manipulators. An approximate fast terminal sliding mode control is proposed by integrating a nonsingular fast terminal sliding surface with an exponential reaching law. Lyapunov stability theory is employed to prove the global approximate finite-time stability ensuring that the tracking errors converge to an arbitrary small ball centered at zero within a finite time and thereafter arrive at zero asymptotically. The benefits of this integrated design are that it can ensure faster transient and higher steady-state tracking precision with lower chattering. Simulations and experiments are presented to demonstrate the effectiveness and improved performances of the proposed approach.

A novel robust finite-time tracking control of uncertain robotic manipulators with disturbances

2020 ◽  
pp. 107754632098244
Author(s):  
Hamid Razmjooei ◽  
Mohammad Hossein Shafiei ◽  
Elahe Abdi ◽  
Chenguang Yang
Keyword(s):  
Finite Time ◽  
Control Method ◽  
Sliding Mode ◽  
Robotic Manipulators ◽  
Sliding Mode Controller ◽  
Time Varying ◽  
State Variables ◽  
Terminal Sliding Mode ◽  
Control Laws ◽  
Finite Time Boundedness

In this article, an innovative technique to design a robust finite-time state feedback controller for a class of uncertain robotic manipulators is proposed. This controller aims to converge the state variables of the system to a small bound around the origin in a finite time. The main innovation of this article is transforming the model of an uncertain robotic manipulator into a new time-varying form to achieve the finite-time boundedness criteria using asymptotic stability methods. First, based on prior knowledge about the upper bound of uncertainties and disturbances, an innovative finite-time sliding mode controller is designed. Then, the innovative finite-time sliding mode controller is developed for finite-time tracking of time-varying reference signals by the outputs of the system. Finally, the efficiency of the proposed control laws is illustrated for serial robotic manipulators with any number of links through numerical simulations, and it is compared with the nonsingular terminal sliding mode control method as one of the most powerful finite-time techniques.

Terminal sliding mode control of permanent magnet synchronous motor based on the reaching law

2019 ◽  
Vol 234 (7) ◽  
pp. 849-859
Author(s):  
Peikun Zhu ◽  
Yong Chen ◽  
Meng Li
Keyword(s):  
Sliding Mode Control ◽  
Permanent Magnet ◽  
Parameter Uncertainty ◽  
Control Algorithm ◽  
Sliding Mode ◽  
Permanent Magnet Synchronous Motor ◽  
Synchronous Motor ◽  
Terminal Sliding Mode ◽  
Reaching Law ◽  
Mode Control

Aiming at the parameter uncertainty and load torque disturbance of permanent magnet synchronous motor system, a terminal sliding mode control algorithm for permanent magnet synchronous motor based on the reaching law is proposed. First, a sliding mode control algorithm for sliding mode reaching law is proposed, which can dynamically adapt to the changes in system state. Second, a sliding mode disturbance observer is designed to estimate the lumped disturbance in real time and to compensate the controller for disturbance. On this basis, an online identification method based on disturbance observer for viscous friction coefficient and moment of inertia is used to reduce the influence of parameter uncertainty on the control system. Simulation and experimental results show the effectiveness of the method.

Super-twisting disturbance observer-based finite- time attitude stabilization of flexible spacecraft subject to complex disturbances

2018 ◽  
Vol 25 (5) ◽  
pp. 1008-1018 ◽  
Author(s):  
Ruidong Yan ◽  
Zhong Wu
Keyword(s):  
Attitude Control ◽  
Disturbance Observer ◽  
Sliding Mode ◽  
State Variables ◽  
Attitude Dynamics ◽  
Attitude Control System ◽  
Terminal Sliding Mode ◽  
Nonlinear Disturbance Observer ◽  
Attitude Stabilization ◽  
Nonsingular Terminal Sliding Mode

There exist complex disturbances in the attitude control system of flexible spacecrafts, such as space environmental disturbances, flexible vibrations, inertia uncertainties, payload motions, etc. To suppress the effects of these disturbances on the performance of attitude stabilization, a super-twisting disturbance observer (STDO)-based nonsingular terminal sliding mode controller (NTSMC) is proposed in this paper. First, STDO is designed for a second-order dynamical system constructed by applying the lumped disturbance and its integral as state variables, and applying the integral as virtual measurement. Since the virtual measurement is obtained by integrating the inverse attitude dynamics, STDO not only avoids the differential operation of angular velocity, but also fully utilizes the information of a nonlinear model. By combining STDO with NTSMC, a composite controller is designed to achieve high-accuracy spacecraft attitude stabilization. Since most of the disturbances are compensated for by a STDO-based feedforward compensator, only a small switching gain is required to deal with the residual disturbances and uncertainties. Thus, the chattering phenomenon of the controller can be alleviated to a great extent. Finally, numerical simulations for the comparison between STDO-based NTSMC and nonlinear disturbance observer-based NTSMC are carried out in the presence of complex disturbances to verify the effectiveness of the proposed approach.

scholarly journals Exponential Reaching Law and Sensorless DTC IM Control with Neural Network Online Parameters Estimation based on MRAS

2018 ◽  
Vol 7 (2) ◽  
pp. 77
Author(s):  
Legrioui Said ◽  
Rezgui Salah Eddine ◽  
Benalla Hocine
Keyword(s):  
Neural Network ◽  
Time Constant ◽  
Sliding Mode ◽  
Direct Torque Control ◽  
Parameters Estimation ◽  
Torque Control ◽  
System Control ◽  
Reaching Law ◽  
Exponential Reaching Law ◽  
Stator Resistance

The most important problem in the control of induction machine (IM) is the change of its parameters, especially the stator resistance and rotor-time constant. The objective of<em> </em>this paper is to implement a new strategy in sensorless direct torque control (DTC) of an IM drive. The rotor flux based model reference adaptive system (MRAS) is used<em> </em>to estimate conjointly<em> </em>the rotor<em> </em>speed, the stator resistance and the inverse rotor time constant, the process of the estimation is performed on-line by a new MRAS-based artificial neural network (ANN) technique. Furthermore, the drive is complemented with a new exponential reaching law (ERL), based on the sliding mode control (SMC) to significantly improve the performances of the system control compared to the conventional SMC which is known to be susceptible to the annoying chattering phenomenon. An experimental investigation was carried out via the Matlab/Simulink with real time interface (RTI) and dSPACE (DS1104) board where the behavior of the proposed method was tested at different points of IM operation.

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