scholarly journals Formation Control of Unmanned Vessels with Saturation Constraint and Extended State Observation

2021 ◽  
Vol 9 (7) ◽  
pp. 772
Author(s):  
Huixuan Fu ◽  
Shichuan Wang ◽  
Yan Ji ◽  
Yuchao Wang
Keyword(s):  
Formation Control ◽  
Control Method ◽  
Tracking Error ◽  
External Environment ◽  
Control Force ◽  
Extended State ◽  
Parameter Perturbation ◽  
State Observation ◽  
Saturation Constraint ◽  
The Stability

This paper addressed the formation control problem of surface unmanned vessels with model uncertainty, parameter perturbation, and unknown environmental disturbances. A formation control method based on the control force saturation constraint and the extended state observer (ESO) was proposed. Compared with the control methods which only consider the disturbances from external environment, the method proposed in this paper took model uncertainties, parameter perturbation, and external environment disturbances as the compound disturbances, and the ESO was used to estimate and compensate for the disturbances, which improved the anti-disturbance performance of the controller. The formation controller was designed with the virtual leader strategy, and backstepping technique was designed with saturation constraint (SC) function to avoid the lack of force of the actuator. The stability of the closed-loop system was analyzed with the Lyapunov method, and it was proved that the whole system is uniformly and ultimately bounded. The tracking error can converge to arbitrarily small by choosing reasonable controller parameters. The comparison and analysis of simulation experiments showed that the controller designed in this paper had strong anti-disturbance and anti-saturation performance to the compound disturbances of vessels and can effectively complete the formation control.

scholarly journals Extended-State-Observer-Based Super Twisting Control for Pneumatic Muscle Actuators

Actuators ◽  
2021 ◽  
Vol 10 (2) ◽  
pp. 35
Author(s):  
Yu Cao ◽  
Zhongzheng Fu ◽  
Mengshi Zhang ◽  
Jian Huang
Keyword(s):  
Control Method ◽  
Experimental Studies ◽  
State Observer ◽  
Extended State Observer ◽  
Extended State ◽  
Pneumatic Muscle ◽  
System States ◽  
The Stability ◽  
Twisting Control ◽  
Muscle Actuators

This paper presents a tracking control method for pneumatic muscle actuators (PMAs). Considering that the PMA platform only feedbacks position, and the velocity and disturbances cannot be observed directly, we use the extended-state-observer (ESO) for simultaneously estimating the system states and disturbances by using measurable variables. Integrated with the ESO, a super twisting controller (STC) is design based on estimated states to realize the high-precision tracking. According to the Lyapunov theorem, the stability of the closed-loop system is ensured. Simulation and experimental studies are conducted, and the results show the convergence of the ESO and the effectiveness of the proposed method.

Velocity-free distributed geometric formation control for underactuated UAVs

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Yanjie Chen ◽  
Weiwei Zhan ◽  
Yibin Huang ◽  
Zhiqiang Miao ◽  
Yaonan Wang
Keyword(s):  
Attitude Control ◽  
Formation Control ◽  
Control Method ◽  
Controller Design ◽  
Linear Velocity ◽  
Nonlinear Controller ◽  
Content Type ◽  
Distributed Controller ◽  
Cascade Structure ◽  
The Stability

Purpose This paper aims to investigate the distributed formation control problem for a multi-quadrotor unmanned aerial vehicle system without linear velocity feedbacks. Design/methodology/approach A nonlinear controller is proposed based on the orthogonal group SE(3) to obviate singularities and ambiguities of the traditional parameterized attitude representations. A cascade structure is applied in the distributed controller design. The inner loop is responsible for attitude control, and the outer loop is responsible for translational dynamics. To ensure a linear-velocity-free characteristic, some auxiliary variables are introduced to construct virtual signals in distributed controller design. The stability analysis of the proposed distributed control method by the Lyapunov function is provided as well. Findings A group of four quadrotors with constant reference linear velocity and a group of six quadrotors with varying reference linear velocity are adopted to verify the effectiveness of the proposed strategy. Originality/value This is a new innovation for multi-robot formation control method to improve assembly automation.

scholarly journals Iterative Learning Control with Extended State Observer for Telescope System

2015 ◽  
Vol 2015 ◽  
pp. 1-8 ◽  
Author(s):  
Huaxiang Cai ◽  
Yongmei Huang ◽  
Junfeng Du ◽  
Tao Tang ◽  
Dan Zuo ◽  
...  
Keyword(s):  
Iterative Learning Control ◽  
Control Method ◽  
Tracking Error ◽  
Learning Control ◽  
State Observer ◽  
Iterative Learning ◽  
Extended State Observer ◽  
Extended State ◽  
Nonlinear Disturbances ◽  
Telescope System

An Iterative Learning Control (ILC) method with Extended State Observer (ESO) is proposed to enhance the tracking precision of telescope. Telescope systems usually suffer some uncertain nonlinear disturbances, such as nonlinear friction and unknown disturbances. Thereby, to ensure the tracking precision, the ESO which can estimate system states (including parts of uncertain nonlinear disturbances) is introduced. The nonlinear system is converted to an approximate linear system by making use of the ESO. Besides, to make further improvement on the tracking precision, we make use of the ILC method which can find an ideal control signal by the process of iterative learning. Furthermore, this control method theoretically guarantees a prescribed tracking performance and final tracking accuracy. Finally, a few comparative experimental results show that the proposed control method has excellent performance for reducing the tracking error of telescope system.

Task-space asymptotic tracking control of robots using a direct adaptive Taylor series controller

2018 ◽  
Vol 24 (23) ◽  
pp. 5570-5584 ◽  
Author(s):  
Seyed Mohammad Ahmadi ◽  
Mohammad Mehdi Fateh
Keyword(s):  
Taylor Series ◽  
Control Method ◽  
Tracking Error ◽  
Time Derivative ◽  
Approximation Error ◽  
Task Space ◽  
Control Approach ◽  
Control Scheme ◽  
Asymptotic Tracking ◽  
The Stability

This paper presents a robust task-space control approach using a direct adaptive Taylor series controller for electrically driven robot manipulators. In an adaptive Taylor series control scheme, the parameters of controller are directly tuned in order to reduce the task-space tracking error in the presence of structured and unstructured uncertainty. Also, the upper bound of approximation error is estimated to form a robustifying term and the asymptotic convergence of task-space tracking error and its time derivative is proven based on the stability analysis. Simulation results are included to verify the effectiveness of the proposed control method.

Active Control of Longitudinal Vibration of a Time-Varying Shafting System With a Dynamic Interpolating Adaptive Method

2018 ◽  
Vol 141 (1) ◽  
Author(s):  
Hongbo Zheng ◽  
Fang Hu ◽  
Hui Qin ◽  
Zhiyi Zhang
Keyword(s):  
Thrust Bearing ◽  
Control Method ◽  
Longitudinal Vibration ◽  
Adaptive Methods ◽  
Adaptive Method ◽  
Control Force ◽  
Time Varying ◽  
The Stability ◽  
The Right ◽  
Parameter Dependent

An adaptive control method with dynamic interpolation is proposed for the active longitudinal vibration control of propulsion shafting systems. In such systems, the dynamics of longitudinal vibration change with the speed-dependent stiffness, which can result in a time-varying system as the shaft speed changes with time. A longitudinal vibration model is established for the investigation of the dynamic interpolating adaptive method (DIAM). In this model, the longitudinal vibration is induced by the disturbance exerted on the propeller (the left mass) and the control force is exerted on the thrust bearing (the right mass), which defines the disturbance channel and the control channel. The proposed DIAM is used to suppress longitudinal vibration transmission from the propeller to the thrust bearing by applying an active force on the right mass. The interpolation technique in DIAM updates the parameter-dependent compensator dynamically and eliminates the influence of parameter-dependent dynamics on the stability of control. Simulation results have demonstrated that the proposed DIAM is effective in suppressing longitudinal vibration of the thrust bearing in comparison to conventional adaptive methods.

Boundary Stabilization of Parachute Dams in Contact With Fluid

2011 ◽  
Vol 133 (6) ◽  
Author(s):  
Ali Najafi ◽  
Mohammad Eghtesad ◽  
Farhang Daneshmand ◽  
Amir Lotfazar
Keyword(s):  
Stability Analysis ◽  
Lyapunov Functional ◽  
Control Method ◽  
Nonlinear Partial Differential Equations ◽  
Coupled System ◽  
Control Force ◽  
Boundary Stabilization ◽  
Boundary Feedback ◽  
Boundary Control Method ◽  
The Stability

The boundary stabilization of a coupled fluid-structure system consisting of a vibrating parachute dam in contact with a fluid is studied in this paper. The parachute dam dynamics is presented by nonlinear partial differential equations. The fluid is assumed to be Newtonian, barotropic, and compressible. For the stability analysis of the coupled system, the boundary control method is used; a boundary feedback is constructed to stabilize the vibrations of the dam and the fluid simultaneously. The control force consists of the feedback from dam tension at its end. Moreover, the exponential stabilization of the parachute dam is achieved using a Lyapunov functional and boundary feedback.

scholarly journals Method of Cooperative Formation Control for Underactuated USVS Based on Nonlinear Backstepping and Cascade System Theory

2021 ◽  
Vol 28 (1) ◽  
pp. 149-162
Author(s):  
Zaopeng Dong ◽  
Yang Liu ◽  
Hao Wang ◽  
Tao Qin
Keyword(s):  
System Theory ◽  
Control System ◽  
Formation Control ◽  
Control Method ◽  
Tracking Error ◽  
Lyapunov Stability Theory ◽  
State Variables ◽  
State Transformation ◽  
Cascade System ◽  
Control Laws

Abstract This paper presents a method for the cooperative formation control of a group of underactuated USVs. The problem of formation control is first converted to one of stabilisation control of the tracking errors of the follower USVs using system state transformation design. The followers must keep a fixed distance from the leader USV and a specific heading angle in order to maintain a certain type of formation. A global differential homeomorphism transformation is then designed to create a tracking error system for the follower USVs, in order to simplify the description of the control system. This makes the complex formation control system easy to analyse, and allows it to be decomposed into a cascaded system. In addition, several intermediate state variables and virtual control laws are designed based on nonlinear backstepping, and actual control algorithms for the follower USVs to control the surge force and yaw moment are presented. A global system that can ensure uniform asymptotic stability of the USVs’ cooperative formation control is achieved by combining Lyapunov stability theory and cascade system theory. Finally, several simulation experiments are carried out to verify the validity, stability and reliability of our cooperative formation control method.

Observer based direct adaptive fuzzy second-order-like sliding mode control for unknown nonlinear systems

2020 ◽  
pp. 095440892095259
Author(s):  
Hongzhuang Wu ◽  
Songyong Liu ◽  
Cheng Cheng ◽  
Changlong Du
Keyword(s):  
Sliding Mode Control ◽  
Control Method ◽  
Nonlinear Dynamical Systems ◽  
Sliding Mode ◽  
Tracking Error ◽  
Second Order ◽  
Control Law ◽  
Adaptive Fuzzy ◽  
Mode Control ◽  
The Stability

This work proposes a novel observer based direct adaptive fuzzy second-order-like sliding mode control (SMC) method for a certain class of high order unknown nonlinear dynamical systems with unmeasurable states. An observer is firstly developed to estimate the tracking error vector directly, and the stability of the observer is analyzed based on Meyer-Kalman-Yakubovich (MKY) lemma. Based on the observer, the equivalent control law is approximated by a double-input single-output fuzzy logic system (FLS), in which the observation of the sliding surface and its derivative are applied as the inputs. In addition, an adaptive switching control law is added to mitigate the system chattering and improve the stability of the system. The free parameters of the controller are adjusted online by the adaptive laws that are derived from the Lyapunov stability analysis. Finally, the convergence of the overall closed-loop system is demonstrated, and the simulation examples illustrate the efficacy of the proposed control method.

Integral terminal sliding mode formation control of non-holonomic robots using leader follower approach

Robotica ◽  
2016 ◽  
Vol 35 (7) ◽  
pp. 1473-1487 ◽  
Author(s):  
Muhammad Asif ◽  
Muhammad Junaid Khan ◽  
Attaullah Y. Memon
Keyword(s):  
Formation Control ◽  
Sliding Mode ◽  
Tracking Error ◽  
Obstacle Detection ◽  
Lyapunov Theory ◽  
Terminal Sliding Mode ◽  
Loop Control ◽  
The Stability ◽  
Close Loop Control ◽  
Multi Robot

SUMMARYMulti-robot formation control has become an important area of research due to its advantages and applications. This paper presents multi-robot formation control using a leader–follower approach without considering the leader's velocity information or estimation. The leader–follower formation is formulated by incorporating the model uncertainties and disturbances. A novel formation controller is presented using integral terminal sliding mode (ITSM) control, which drives the formation tracking error convergence to zero in finite-time. The stability of the close-loop control scheme is verified by using Lyapunov theory. Furthermore, obstacle detection and avoidance are incorporated to avoid collision while maintaining the formation. The effectiveness of the proposed controller is verified and validated using sine and lamniscate curve trajectories. Moreover, the performance of the proposed ITSM formation controller is compared with the standard linear sliding mode (LSM) control.

scholarly journals Decoupling Attitude Control of a Hypersonic Glide Vehicle Based on a Nonlinear Extended State Observer

2020 ◽  
Vol 2020 ◽  
pp. 1-11 ◽  
Author(s):  
Jian Chen ◽  
Nannan Du ◽  
Yu Han
Keyword(s):  
Attitude Control ◽  
Closed Loop ◽  
Control Method ◽  
Tracking Error ◽  
State Observer ◽  
Extended State Observer ◽  
Decoupling Control ◽  
Extended State ◽  
Loop Control ◽  
Nonlinear Extended State Observer

Aiming at solving the attitude control problem of a hypersonic glide vehicle, this paper proposes a decoupling control method based on a nonlinear extended state observer (NESO). According to the decentralized robust control theory of Tornambè, the coupling terms and the uncertainties are regarded as generalized uncertainties, and the NESO-based estimation and compensation signals are added to the closed-loop control law. The theoretical deduction proves that the proposed method can ensure that the tracking error of the closed-loop system is uniformly bounded. The simulation is carried out on the hypersonic glide vehicle model and compared with the traditional subchannel feedback control method. The simulation results show that the designed decoupling control method has superior control performances, and the influence of channel-coupling and uncertainty is compensated to a great extent.

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