scholarly journals Fast Terminal Sliding Control of Underactuated Robotic Systems Based on Disturbance Observer with Experimental Validation

Mathematics ◽  
2021 ◽  
Vol 9 (16) ◽  
pp. 1935
Author(s):  
Thaned Rojsiraphisal ◽  
Saleh Mobayen ◽  
Jihad H. Asad ◽  
Mai The Vu ◽  
Arthur Chang ◽  
...  
Keyword(s):  
Finite Time ◽  
Disturbance Observer ◽  
Sliding Mode ◽  
Robotic Systems ◽  
Control Technique ◽  
Control Law ◽  
External Disturbances ◽  
Terminal Sliding Mode ◽  
Inverted Pendulum System ◽  
Fast Terminal Sliding Mode

In this study, a novel fast terminal sliding mode control technique based on the disturbance observer is recommended for the stabilization of underactuated robotic systems. The finite time disturbance observer is employed to estimate the exterior disturbances of the system and develop the finite time control law. The proposed controller can regulate the state trajectories of the underactuated systems to the origin within a finite time in the existence of external disturbances. The stability analysis of the proposed control scheme is verified via the Lyapunov stabilization theory. The designed control law is enough to drive a switching surface achieving the fast terminal sliding mode against severe model nonlinearities with large parametric uncertainties and external disturbances. Illustrative simulation results and experimental validations on a cart-inverted pendulum system are provided to display the success and efficacy of the offered method.

scholarly journals A Composite Guidance Law for Suppressing Measurement Noise of LOS Angular Rate

2019 ◽  
Vol 2019 ◽  
pp. 1-10
Author(s):  
Feng Chen ◽  
Guangjun He ◽  
Qifang He
Keyword(s):  
Sliding Mode Control ◽  
Finite Time ◽  
Disturbance Observer ◽  
Sliding Mode ◽  
Angular Rate ◽  
Measurement Noise ◽  
Terminal Sliding Mode ◽  
Guidance Law ◽  
Fast Terminal Sliding Mode ◽  
Low Altitude

To effectively intercept a low-altitude target in clutter background, a nonsingular fast terminal sliding mode guidance law is designed. The designed guidance law can fully exploit the fast convergence characteristics of linear sliding mode control and the finite-time-convergent characteristics of terminal sliding mode control to ensure that the line-of-sight (LOS) angle converges to a desired angle in a limited time at a faster rate. Utilizing the smooth switching characteristics of the hyperbolic tangent function similar to the saturation function, a finite-time-convergent differentiator is designed. Meanwhile, a new finite-time-convergent disturbance observer designed on the tracking differentiator can effectively track the ideal LOS angular rate, suppress the measurement noise, and make a smooth estimation of the target maneuvering acceleration in clutter background. Combining the estimated value of the disturbance observer, the sign function with switch coefficient is introduced to design a composite nonsingular fast terminal sliding mode guidance law. The simulation results show that the composite guidance law can not only effectively suppress the measurement noise of the LOS angular rate and improve the accuracy of low-altitude target intercepting, but also greatly reduce the energy consumption in the interception process.

Finite-time fault-tolerant attitude tracking control for spacecraft without unwinding

2018 ◽  
Vol 233 (6) ◽  
pp. 2119-2130 ◽  
Author(s):  
Bing Huang ◽  
Ai-jun Li ◽  
Yong Guo ◽  
Chang-qing Wang ◽  
Jin-hua Guo
Keyword(s):  
Finite Time ◽  
Tracking Control ◽  
Fault Tolerant ◽  
Sliding Mode ◽  
External Disturbances ◽  
Terminal Sliding Mode ◽  
Attitude Tracking ◽  
Control Schemes ◽  
Fast Terminal Sliding Mode ◽  
Attitude Tracking Control

This paper investigates the finite-time attitude tracking control problem for spacecraft in the presence of external disturbances and actuator faults. Two anti-unwinding attitude tracking control schemes have been proposed based on the rotation matrix and sliding mode control technology. Utilizing a fast terminal sliding mode surface, the first controller can fulfill the finite-time attitude tracking control task with disturbance rejection ability. The second controller can improve the system reliability when the actuator fault occurs. Rigorous mathematical analysis and proof concludes that the proposed controllers can make a spacecraft track the desired attitude command in finite time. Numerical simulation results are presented to demonstrate the effectiveness of the proposed controllers.

scholarly journals An Active Fault-Tolerant Control for Robotic Manipulators Using Adaptive Non-Singular Fast Terminal Sliding Mode Control and Disturbance Observer

Actuators ◽  
2021 ◽  
Vol 10 (12) ◽  
pp. 332
Author(s):  
Van-Cuong Nguyen ◽  
Phu-Nguyen Le ◽  
Hee-Jun Kang
Keyword(s):  
Sliding Mode Control ◽  
Finite Time ◽  
Disturbance Observer ◽  
Fault Tolerant ◽  
Sliding Mode ◽  
Robotic Manipulators ◽  
Terminal Sliding Mode Control ◽  
Terminal Sliding Mode ◽  
Finite Time Convergence ◽  
Fast Terminal Sliding Mode

In this study, a fault-tolerant control (FTC) tactic using a sliding mode controller–observer method for uncertain and faulty robotic manipulators is proposed. First, a finite-time disturbance observer (DO) is proposed based on the sliding mode observer to approximate the lumped uncertainties and faults (LUaF). The observer offers high precision, quick convergence, low chattering, and finite-time convergence estimating information. Then, the estimated signal is employed to construct an adaptive non-singular fast terminal sliding mode control law, in which an adaptive law is employed to approximate the switching gain. This estimation helps the controller automatically adapt to the LUaF. Consequently, the combination of the proposed controller–observer approach delivers better qualities such as increased position tracking accuracy, reducing chattering effect, providing finite-time convergence, and robustness against the effect of the LUaF. The Lyapunov theory is employed to illustrate the robotic system’s stability and finite-time convergence. Finally, simulations using a 2-DOF serial robotic manipulator verify the efficacy of the proposed method.

Disturbance observer and finite-time tracker design of disturbed third-order nonholonomic systems using terminal sliding mode

2016 ◽  
Vol 23 (2) ◽  
pp. 181-189 ◽  
Author(s):  
Saleh Mobayen ◽  
Shamsi Javadi
Keyword(s):  
Finite Time ◽  
Tracking Control ◽  
Disturbance Observer ◽  
Sliding Mode ◽  
Approximation Error ◽  
Nonholonomic Systems ◽  
Control Technique ◽  
Third Order ◽  
Terminal Sliding Mode ◽  
Finite Time Convergence

This paper proposes a novel recursive terminal sliding mode structure for tracking control of third-order chained–form nonholonomic systems in the presence of the unknown external disturbances. Finite-time convergence of the disturbance approximation error is guaranteed using the designed disturbance observer. Under the proposed terminal sliding model tracking control technique, the finite-time convergence of the states of the closed-loop system is guaranteed via Lyapunov analysis. A new reaching control law is proposed to guarantee the existence of the sliding mode around the recursive TSM surface in a finite-time. Simulation results are illustrated on a benchmark example of third-order chained-form nonholonomic systems: a wheeled mobile robot. The results demonstrate that the proposed control technique achieves promising tracking performance for nonholonomic systems.

scholarly journals Stabilization of a Class of Nonlinear Underactuated Robotic Systems through Nonsingular Fast Terminal Sliding Mode Control

2020 ◽  
Vol 2020 ◽  
pp. 1-9
Author(s):  
Yaobin Song ◽  
Hui Li ◽  
Xiaoling Shi
Keyword(s):  
Sliding Mode Control ◽  
Control Method ◽  
Sliding Mode ◽  
Direct Method ◽  
Robotic Systems ◽  
Control Technique ◽  
Terminal Sliding Mode Control ◽  
Terminal Sliding Mode ◽  
Mode Control ◽  
Fast Terminal Sliding Mode

To facilitate the stabilization of nonlinear underactuated robotic systems under perturbation, a novel nonsingular fast terminal sliding mode control method is proposed. Based on the system transformation into an integrator chain, the combination of twisting-like algorithm and a nonsingular fast terminal sliding mode control technique is employed to achieve the stabilization of the studied systems, which can drive the robot states (joint positions and velocities) to the desired region and then maintain the system at the equilibrium point in finite time. The robustness of the proposed method is validated by the Lyapunov direct method. Finally, numerical simulation results further demonstrate that the proposed method has better performance on the convergent speed of the system state (robot joint positions and velocities) than state-of-the-art methods, especially for the underactuated joints.

Distributed attitude consensus tracking control for spacecraft formation flying via adaptive nonsingular fast terminal sliding mode control

2021 ◽  
pp. 095441002110422
Author(s):  
Xiong Xie ◽  
Tao Sheng ◽  
Liang He ◽  
Zhijun Chen ◽  
Yong Zhao
Keyword(s):  
Tracking Control ◽  
Sliding Mode ◽  
Control Law ◽  
Model Uncertainties ◽  
External Disturbances ◽  
Terminal Sliding Mode ◽  
Spacecraft Formation ◽  
Spacecraft Formation Flying ◽  
Consensus Tracking ◽  
Fast Terminal Sliding Mode

This article investigates the distributed attitude consensus tracking control for spacecraft formation flying with unknown external disturbances and model uncertainties. First, a terminal sliding mode disturbance observer (TSMDO) is constructed to estimate the generalized disturbances including external disturbances and model uncertainties. The finite-time convergence of the estimation errors using TSMDO is analyzed. Second, a variable structure control law is developed to avoid introducing initial errors of the TSMDO. Third, a novel adaptive nonsingular fast terminal sliding mode (ANFTSM) control law based on TSMDO is proposed to ensure the convergence of attitude tracking errors to zero. Based on theoretical analysis, the finite-time stability can be guaranteed by Lyapunov theory. Finally, the effectiveness of the developed control law is verified via numerical simulations.

Design of a non-singular fast terminal sliding mode control for second-order nonlinear systems with compound disturbance

2021 ◽  
pp. 095440622110329
Author(s):  
Mohammad Reza Salehi Kolahi ◽  
Mohammad Reza Gharib ◽  
Ali Heydari
Keyword(s):  
Sliding Mode Control ◽  
Sliding Mode ◽  
Path Tracking ◽  
Second Order ◽  
Control Technique ◽  
Terminal Sliding Mode Control ◽  
Terminal Sliding Mode ◽  
Mode Control ◽  
Fast Terminal Sliding Mode ◽  
Compound Disturbance

This paper investigates a new disturbance observer based non-singular fast terminal sliding mode control technique for the path tracking and stabilization of non-linear second-order systems with compound disturbance. The compound disturbance is comprised of both parametric and non-parametric uncertainties. While warranting fast convergence rate and robustness, it also dominates the singularity and complex-value number issues associated with conventional terminal sliding mode control. Furthermore, due to the estimation properties of the observer, knowledge about the bounds of the uncertainties is not required. The simulation results of two case studies, the velocity and path tracking of an autonomous underwater vehicle and the stabilization of a chaotic Φ6-Duffing oscillator, validate the efficacy of the proposed method.

scholarly journals Design of Composite Disturbance Observer and Continuous Terminal Sliding Mode Control for Piezoelectric Nanopositioning Stage

Electronics ◽  
2021 ◽  
Vol 10 (18) ◽  
pp. 2242
Author(s):  
Pengyu Qiao ◽  
Jun Yang ◽  
Chen Dai ◽  
Xi Xiao
Keyword(s):  
Sliding Mode Control ◽  
Control Strategy ◽  
Disturbance Observer ◽  
Sliding Mode ◽  
Accurate Estimation ◽  
Terminal Sliding Mode Control ◽  
External Disturbances ◽  
Terminal Sliding Mode ◽  
Composite Control ◽  
Mode Control

The nonlinearities of piezoelectric actuators and external disturbances of the piezoelectric nanopositioning stage impose great, undesirable influences on the positioning accuracy of nanopositioning stage systems. This paper considers nonlinearities and external disturbances as a lumped disturbance and designs a composite control strategy for the piezoelectric nanopositioning stage to realize ultra-high precision motion control. The proposed strategy contains a composite disturbance observer and a continuous terminal sliding mode controller. The composite disturbance observer can estimate both periodic and aperiodic disturbances so that the composite control strategy can deal with the disturbances with high accuracy. Meanwhile, the continuous terminal sliding mode control is employed to eliminate the chattering phenomenon and speed up the convergence rate. The simulation and experiment results show that the composite control strategy achieves accurate estimation of different forms of disturbances and excellent tracking performance.

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