scholarly journals Chattering-Suppressed Sliding Mode Control for Flexible-Joint Robot Manipulators

Actuators ◽  
2021 ◽  
Vol 10 (11) ◽  
pp. 288
Author(s):  
Xin Cheng ◽  
Huashan Liu ◽  
Wenke Lu
Keyword(s):  
Tracking Control ◽  
Sliding Mode ◽  
Robot Manipulators ◽  
Dynamic Performance ◽  
Singular Perturbation Theory ◽  
External Disturbances ◽  
Flexible Joint ◽  
Control Approach ◽  
Control Objective ◽  
Saturation Factor

In this paper, sliding mode tracking control and its chattering suppression method are investigated for flexible-joint robot manipulators with only state measurements of joint actuators. First, within the framework of singular perturbation theory, the control objective of the system is decoupled into two typical tracking aims of a slow subsystem and a fast subsystem. Then, considering lumped uncertainties (including dynamics uncertainties and external disturbances), a composite chattering-suppressed sliding mode controller is proposed, where a smooth-saturation-function-contained reaching law with adjustable saturation factor is designed to alleviate the inherent chattering phenomenon, and a radial basis function neural network (RBFNN)-based soft computing strategy is applied to avoid the high switching gain that leads to chattering amplification. Simultaneously, an efficient extended Kalman filter (EKF) with respect to a new state variable is presented to enable the closed-loop tracking control with neither position nor velocity measurements of links. In addition, an overall analysis on the asymptotic stability of the whole control system is given. Finally, numerical examples verify the superiority of the dynamic performance of the proposed control approach, which is well qualified to suppress the chattering and can effectively eliminate the undesirable effects of the lumped uncertainties with a smaller switching gain reduced by 80% in comparison to that in the controller without RBFNN. The computational efficiency of the proposed EKF increased by about 26%.

Observer-based adaptive neural sliding mode trajectory tracking control for remotely operated vehicles with thruster constraints

2021 ◽  
pp. 014233122110048
Author(s):  
Zhenzhong Chu ◽  
Yunsai Chen ◽  
Daqi Zhu ◽  
Mingjun Zhang
Keyword(s):  
Neural Networks ◽  
Trajectory Tracking ◽  
Tracking Control ◽  
Sliding Mode ◽  
Auxiliary System ◽  
Rbf Neural Networks ◽  
Remotely Operated Vehicle ◽  
Trajectory Tracking Control ◽  
Control Approach ◽  
Saturation Factor

For a class of remotely operated vehicle (ROV) systems with thruster constraints, immeasurable states, and unknown nonlinearities, the trajectory tracking control problem was discussed in this paper. The unknown nonlinear functions were approximated by radial basis function (RBF) neural networks. An adaptive state observer based on neural networks was designed and the immeasurable states were estimated. Considering the problem of thruster saturation constraints, an auxiliary system for saturation compensation was designed and a saturation factor was constructed by the auxiliary system state. By applying the backstepping design method, an adaptive neural sliding mode trajectory tracking controller was developed, in which the saturation factor is contained in adaptive laws. It was proved that the uniformly ultimately bounded (UUB) of trajectory tracking errors can be obtained. Finally, the effectiveness of the proposed trajectory tracking control approach was checked by simulations.

Tracking control via switched Integral Sliding Mode with application to robot manipulators

2019 ◽  
Vol 90 ◽  
pp. 257-266 ◽  
Author(s):  
Antonella Ferrara ◽  
Gian Paolo Incremona ◽  
Bianca Sangiovanni
Keyword(s):  
Tracking Control ◽  
Sliding Mode ◽  
Robot Manipulators ◽  
Integral Sliding Mode

scholarly journals Adaptive output feedback integral sliding mode attitude tracking control of spacecraft without unwinding

2017 ◽  
Vol 9 (7) ◽  
pp. 168781401771040 ◽  
Author(s):  
Anuchit Jitpattanakul ◽  
Chutiphon Pukdeboon
Keyword(s):  
Output Feedback ◽  
Tracking Control ◽  
Sliding Mode ◽  
Control Technique ◽  
Control Law ◽  
Parameter Uncertainties ◽  
External Disturbances ◽  
Integral Sliding Mode ◽  
Attitude Tracking ◽  
Attitude Tracking Control

This article studies an output feedback attitude tracking control problem for rigid spacecraft in the presence of parameter uncertainties and external disturbances. First, an anti-unwinding attitude control law is designed using the integral sliding mode control technique to achieve accurate tracking responses and robustness against inertia uncertainties and external disturbances. Next, the derived control law is combined with a suitable tuning law to relax the knowledge about the bounds of uncertainties and disturbances. The stability results are rigorously proved using the Lyapunov stability theory. In addition, a new finite-time sliding mode observer is developed to estimate the first time derivative of attitude. A new adaptive output feedback attitude controller is designed based on the estimated results, and angular velocity measurements are not required in the design process. A Lyapunov-based analysis is provided to demonstrate the uniformly ultimately bounded stability of the observer errors. Numerical simulations are given to illustrate the effectiveness of the proposed control method.

scholarly journals Containment Control of Underactuated Ships with Environment Disturbances and Parameter Uncertainties

2017 ◽  
Vol 2017 ◽  
pp. 1-19 ◽  
Author(s):  
Qidan Zhu ◽  
Junda Ma ◽  
Zhilin Liu ◽  
Ke Liu
Keyword(s):  
Control Algorithm ◽  
Sliding Mode ◽  
Parameter Uncertainties ◽  
Feedback Form ◽  
Tracking Errors ◽  
External Disturbances ◽  
Simulation Experiments ◽  
Containment Control ◽  
State Information ◽  
Control Objective

An implementable robust containment control algorithm is proposed for a group of underactuated ships in the presence of hydrodynamic parameter uncertainties and external disturbances. The control objective is to drive all the followers into the convex hull spanned by the virtual leaders, whose state information is available only to a subset of the followers. For this purpose, the ship model is primarily transformed to a strict-feedback form. In the kinematic design, a virtual containment controller, requiring the state information from its neighbors, is presented based on the results obtained from graph theory. In the dynamic design, a robust containment controller is developed through utilizing upper-to-up sliding mode control. In addition, in order to simplify the implementations of the control law, the command filtered backstepping (CFBP) method is introduced to prevent the analytic differentiations of the virtual law from each design step of the backstepping (BP) method. Subsequently, it is well proven that all the tracking errors could converge to and remain small neighborhoods of the equilibrium point. Finally, several simulation experiments are conducted to demonstrate the performance of the proposed control algorithm.

Finite-time attitude tracking control of air bearing table for spacecraft rendezvous and docking

2016 ◽  
Vol 232 (1) ◽  
pp. 96-110 ◽  
Author(s):  
Cheng Huang ◽  
Yan Wang ◽  
Xing-lin Chen
Keyword(s):  
Finite Time ◽  
Tracking Control ◽  
Sliding Mode ◽  
External Disturbances ◽  
Terminal Sliding Mode ◽  
Finite Time Stability ◽  
Nonsingular Terminal Sliding Mode ◽  
Attitude Tracking ◽  
Attitude Tracking Control ◽  
Rendezvous And Docking

This paper studies the problem of attitude tracking control for spacecraft rendezvous and docking based on a physical ground simulation system. Two finite-time controllers based on quaternion are proposed by using a novel fast nonsingular terminal sliding mode surface associated with the adaptive control, the novel fast nonsingular terminal sliding mode surface not only contains the advantages of the fast nonsingular terminal sliding mode surface, but also can eliminate unwinding caused by the quaternion. The first controller, which is continuous and chattering-free, can compensate unknown constant external disturbances, while the second controller can both compensate parametric uncertainties and varying external disturbances with unknown bounds without chattering. Lyapunov theoretical analysis and simulation results show that the two controllers can make the closed-loop system errors converge to zero in finite time and guarantee the finite-time stability of the system.

Switch-Based Sliding Mode Control for Position-Based Visual Servoing of Robotic Riveting System

2016 ◽  
Vol 139 (4) ◽  
Author(s):  
Yi Min Zhao ◽  
Yu Lin ◽  
Fengfeng Xi ◽  
Shuai Guo ◽  
Puren Ouyang
Keyword(s):  
Visual Servoing ◽  
Sliding Mode ◽  
Dynamic Performance ◽  
Path Following ◽  
External Disturbances ◽  
Control Scheme ◽  
Riveting Process ◽  
The Stability ◽  
Time Required ◽  
Two Stages

The robotic riveting system requires a rivet robotic positioning process for rivet-in-hole insertions, which can be divided into two stages: rivet path-following and rivet spot-positioning. For the first stage, varying parameter-linear sliding surfaces are proposed to achieve robust rivet path-following against robot errors and external disturbances of the robotic riveting system. For the second stage, a second-order sliding surface is applied to attain accurate rivet spot-positioning within a finite time required by the riveting process. In order to improve the dynamic performance of the robot riveting system, the motion of robot end-effector between the two adjacent riveting spots has been properly designed. Overall, the proposed control scheme can guarantee not only the stability of the robot control system but also the robust rivet path-following and quick rivet spot-positioning in the presence of the robot errors and external disturbances of the robotic riveting system. The simulation and experimental results demonstrate the effectiveness of the proposed control scheme.

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