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.

Adaptive altitude flight control of quadcopter under ground effect and time-varying load: theory and experiments

2021 ◽  
pp. 107754632110501
Author(s):  
Ji-Won Lee ◽  
Nguyen Xuan-Mung ◽  
Ngoc Phi Nguyen ◽  
Sung Kyung Hong
Keyword(s):  
Flight Control ◽  
Control Algorithm ◽  
Sliding Mode ◽  
Ground Effect ◽  
Lyapunov Theory ◽  
Control Technique ◽  
Time Varying ◽  
Control Performance ◽  
Parameter Uncertainties ◽  
Altitude Control

In recent years, the boom of the quadcopter industry resulted in a broad range of real-world applications which highlighted the urgent need to improve quadcopter control quality. Typically, external disturbances, such as wind, parameter uncertainties caused by payload variations, or the ground effect, can severely degrade the quadcopter’s altitude control performance. Meanwhile, widely used controllers like the proportional-integral-derivative control cannot guarantee control performance when the system is critically affected by factors that exhibit a high degree of variability with time. In this paper, an adaptive control algorithm is proposed to improve quadcopter altitude tracking performance in the presence of both the ground effect and a time-varying payload. First, we derive an adaptive altitude control algorithm using the sliding mode control technique to account for these uncertainties in the quadcopter dynamics model. Second, we apply Lyapunov theory to analyze the stability of the closed-loop system. Finally, we conduct several numerical simulations and experiments to validate the effectiveness of the proposed method.

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.

Asymptotic stabilization of a class of uncertain nonlinear time-delay fractional-order systems via a robust delay-independent controller

2017 ◽  
Vol 24 (19) ◽  
pp. 4541-4550 ◽  
Author(s):  
T. Binazadeh ◽  
M. Yousefi
Keyword(s):  
Time Delay ◽  
Fractional Order ◽  
Sliding Mode ◽  
Robust Stabilization ◽  
Delay Systems ◽  
Time Varying ◽  
State Variables ◽  
Parameter Uncertainties ◽  
External Disturbances ◽  
Sliding Manifold

This paper studies the robust stabilization for a class of nonlinear time-delay fractional order (FO) systems in the presence of some practical aspects. The considered aspects in the FO system include: nonlinear Lipschitz functions; time-varying norm-bounded uncertain terms; and time-delays in the state variables. A major challenge in the control of time-delay systems is that the value of delay is usually not perfectly known or it may be even time-varying. In this paper, a novel asymptotic stabilizing control law is proposed which is delay independent and also has a robust manner in the presence of uncertain terms in the model which may be due to model uncertainties (parameter uncertainties or model simplification) and/or external disturbances. The proposed controller is a FO sliding mode controller that is designed such that the closed-loop system is asymptotically delay-independent stable. For this purpose, a FO sliding manifold is introduced and the occurrence of the reaching phase in a finite time is proved. Finally, in order to validate the theoretical results, an example is given and simulation results confirm the appropriate performance of the proposed controller.

scholarly journals Chebyshev Neural Network-Based Adaptive Nonsingular Terminal Sliding Mode Control for Hypersonic Vehicles

2020 ◽  
Vol 2020 ◽  
pp. 1-10
Author(s):  
Ruimin Zhang ◽  
Qiaoyu Chen ◽  
Haigang Guo
Keyword(s):  
Sliding Mode Control ◽  
Attitude Control ◽  
Sliding Mode ◽  
Hypersonic Vehicle ◽  
Parameter Uncertainties ◽  
External Disturbances ◽  
Terminal Sliding Mode ◽  
Mode Control ◽  
Adaptive Law ◽  
Nonsingular Terminal Sliding Mode

This paper presents an adaptive nonsingular terminal sliding mode control approach for the attitude control of a hypersonic vehicle with parameter uncertainties and external disturbances based on Chebyshev neural networks (CNNs). First, a new nonsingular terminal sliding surface is proposed for a general uncertain nonlinear system. Then, a nonsingular sliding mode control is designed to achieve finite-time tracking control. Furthermore, to relax the requirement for the upper bound of the lumped uncertainty including parameter uncertainties and external disturbances, a CNN is used to estimate the lumped uncertainty. The network weights are updated by the adaptive law derived from the Lyapunov theorem. Meanwhile, a low-pass filter-based modification is added into the adaptive law to achieve fast and low-frequency adaptation when using high-gain learning rates. Finally, the proposed approach is applied to the attitude control of the hypersonic vehicle and simulation results illustrate its effectiveness.

scholarly journals Joint torque control of flexible joint robots based on sliding mode technique

2019 ◽  
Vol 16 (3) ◽  
pp. 172988141984671 ◽  
Author(s):  
Gen-Liang Xiong ◽  
Hai-Chu Chen ◽  
Jing-Xin Shi ◽  
Fa-Yun Liang
Keyword(s):  
Sliding Mode ◽  
Joint Stiffness ◽  
Torque Control ◽  
Joint Torque ◽  
Parameter Uncertainties ◽  
External Disturbances ◽  
Control Approach ◽  
Flexible Joint Robots ◽  
Mode Technique ◽  
Sliding Mode Technique

For robots with flexible joints, the joint torque dynamics makes it difficult to control. An effective solution is to carry out a joint torque controller with fast enough dynamic response. This article is dedicated to design such a torque controller based on sliding mode technique. Three joint torque control approaches are proposed: (1) The proportional-derivative (PD)-type controller has some degree of robustness by properly selecting the control gains. (2) The direct sliding mode control approach which fully utilizes the physical properties of electric motors. (3) The sliding mode estimator approach was proposed to compensate the parameter uncertainties and the external disturbances of the joint torque system. These three joint torque controllers are tested and verified by the simulation studies with different reference torque trajectories and under different joint stiffness.

On adaptive sliding mode control for improved quadrotor tracking

2017 ◽  
Vol 24 (14) ◽  
pp. 3219-3230 ◽  
Author(s):  
Sudhir Nadda ◽  
A Swarup
Keyword(s):  
Sliding Mode Control ◽  
Control Method ◽  
Sliding Mode ◽  
Lyapunov Stability Theory ◽  
Adaptive Method ◽  
Adaptation Strategy ◽  
Adaptive Sliding Mode Control ◽  
Parameter Uncertainties ◽  
External Disturbances ◽  
Mode Control

The tracking control of a quadrotor has been considered in this paper. The application of sliding mode control provides robustness against parametric uncertainties, but it requires knowledge of the upper bounds of uncertainties. An adaptation strategy has been proposed to implement sliding mode control, which does not require the upper bound of the uncertainties. The adaptive control law is derived on the basis of Lyapunov stability theory, which guarantees the tracking performance. The adaptation can be tuned faster by proper tuning, and convergence with good tracking can be achieved. The proposed adaptive method has improved robustness and provided simpler implementation. Through an illustrative simulation example, the performance of the proposed control method is presented and also compared with classical sliding mode control from the literature. It is demonstrated that the performance of quadrotor altitude tracking and convergence has been considerably improved while maintaining stability, even in presence of external disturbances and parameter uncertainties.

Modelling and adaptive dynamic sliding mode control of dielectrophoresis-based micromanipulation

2016 ◽  
Vol 40 (1) ◽  
pp. 122-134 ◽  
Author(s):  
Hua Luo ◽  
Weijie Sun ◽  
John TW Yeow
Keyword(s):  
Sliding Mode ◽  
Analytical Models ◽  
Parameter Uncertainties ◽  
Biochemical Engineering ◽  
External Disturbances ◽  
Trajectory Tracking Control ◽  
Adaptive Law ◽  
Challenge Control ◽  
Dynamic Sliding Mode Control ◽  
Dynamic Sliding Mode

Automated, precise single particle manipulation in the microscale is in great demand and is one of the great challenges in biomedical and biochemical engineering. Automatic micromanipulation has also become a microrobotics challenge. Following this challenge, control technology is integrated with dielectrophoresis (DEP)-based micromanipulation technology in this paper to construct automatic DEP-based micromanipulation systems. DEP micromanipulation systems with electrodes of quadrupole polynomial geometry are developed as controllable microactuators. A semianalytical modelling method is proposed to formulate the analytical models of the DEP manipulation systems, which manifests that the DEP manipulation systems are non-affine non-linear systems. Then, taking the parameter uncertainties, unmodelled dynamics and external disturbances into account, an adaptive law combined with a dynamic sliding mode controller is designed for two-dimensional trajectory tracking control of a DEP micromanipulation system. The closed-loop system is proved stable in the presence of bounded lumped uncertainty based on the Lyapunov theorem. Finally, simulation results show the validity of the proposed control design.

scholarly journals Adaptive Synchronization Control of Multiple Vessels with Switching Communication Topologies and Time Delay

2015 ◽  
Vol 2015 ◽  
pp. 1-11
Author(s):  
Fuguang Ding ◽  
Yanqin Ma ◽  
Yuanwei Zhou ◽  
Jiangjun Li
Keyword(s):  
Communication Network ◽  
Time Delay ◽  
Control Algorithm ◽  
Sliding Mode ◽  
Tracking Error ◽  
Movement Control ◽  
Adaptive Synchronization ◽  
Synchronization Control ◽  
External Disturbances ◽  
Varying Time Delay

Recently, synchronization movement control of multiple vessels has been studied broadly. In most of the studies, the communication network among vessels is considered to be fixed and the time delay is often ignored. However, the communication network among vessels maybe vary because of switching of different tasks, and the time delay is necessary to be considered when the communication network is unreliable. In this paper, the synchronization movement of multiple vessels with switching connected communication topologies is studied, and an adaptive synchronization control algorithm that is based on backstepping sliding mode control is proposed. The control algorithm is achieved by defining cross coupling error which is combination of the trajectory tracking error and velocity tracking error. And an adaptive control term is used to estimate the external disturbances, so that the unknown external disturbances can be compensated. Furthermore, the robustness of the control law to time-varying time delay is also discussed. At last, some simulations are carried out to validate the effectiveness of the proposed synchronization control algorithm.

A New Nonsingular Terminal Sliding Mode Control for Rigid Spacecraft Attitude Tracking

2017 ◽  
Vol 140 (5) ◽  
Author(s):  
Zeng Wang ◽  
Yuxin Su ◽  
Liyin Zhang
Keyword(s):  
Equilibrium Point ◽  
Finite Time ◽  
Sliding Mode ◽  
Tracking Errors ◽  
Robust Controller ◽  
External Disturbances ◽  
Terminal Sliding Mode ◽  
Nonsingular Terminal Sliding Mode ◽  
Attitude Tracking ◽  
Rigid Spacecraft

This paper addresses the finite time attitude tracking for rigid spacecraft with inertia uncertainties and external disturbances. First, a new nonsingular terminal sliding mode (NTSM) surface is proposed for singularity elimination. Second, a robust controller based on NTSM is designed to solve the attitude tracking problem. It is proved that the new NTSM can converge to zero within finite time, and the attitude tracking errors converge to an arbitrary small bound centered on equilibrium point within finite time and then go to equilibrium point asymptotically. The appealing features of the proposed control are fast convergence, high precision, strong robustness, and easy implementation. Simulations verify the effectiveness of the proposed approach.

Robust Adaptive Controller Design for a Quadrotor Helicopter

2013 ◽  
Vol 284-287 ◽  
pp. 2296-2300 ◽  
Author(s):  
Kuang Shine Yang ◽  
Chi Cheng Cheng
Keyword(s):  
Attitude Control ◽  
Degrees Of Freedom ◽  
Controller Design ◽  
Sliding Mode ◽  
Underactuated System ◽  
Parameter Uncertainties ◽  
Unknown Parameters ◽  
External Disturbances ◽  
Quadrotor Helicopter ◽  
Robust Adaptive

The quadrotor helicopter is designed to easily move in particular environments because it can take off and land in limited space and easily hover at a fixed location. For this reason, a robust adaptive sliding mode controller is developed to control of a quadrotor helicopter in the presence of external disturbances and parameter uncertainties. The quadrotor helicopter system is a typical underactuated system, which has fewer independent control actuators than degrees of freedom to be controlled. The main contribution here is to afford simulation and verification for the quadrotor helicopter flight controller under the assumption of unknown parameters. By utilizing the Lyapunov stability theorem, we can achieve asymptotic tracking of desired reference commands for the quadrotor helicopter, which is subject to both external disturbances and parametric uncertainties. From the simulation results, the controller was sufficient to achieve position and attitude control of the quadrotor helicopter system, which permits possible real time applications in the near future.

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