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 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.

Constant force control for aluminum wheel hub grinding based on ESO + backstepping

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Shijie Dai ◽  
Yufeng Zhao ◽  
Wenbin Ji ◽  
Jiaheng Mu ◽  
Fengbao Hu
Keyword(s):  
Control Strategy ◽  
Force Control ◽  
Control Method ◽  
Response Speed ◽  
Backstepping Control ◽  
Constant Force ◽  
Content Type ◽  
Disturbance Rejection Control ◽  
The Stability ◽  
Differential Control

Purpose This paper aims to present a control method to realize the constant force grinding of automobile wheel hub. Design/methodology/approach A constant force control strategy combined by extended state observer (ESO) and backstepping control is proposed. ESO is used to estimate the total disturbance to improve the anti-interference and stability of the system and Backstepping control is used to improve the response speed of the system. Findings The simulation and grinding experimental results show that, compared with the proportional integral differential control and active disturbance rejection control, the designed controller can improve the dynamic response performance and anti-interference ability of the system and can quickly track the expected force and improve the grinding quality of the hub surface. Originality/value The main contribution of this paper lies in the proposed of a new constant force control strategy, which significantly improved the stability and precision of grinding force.

Rotational and relative translational control for satellite electromagnetic formation flying in low earth orbit

2017 ◽  
Vol 89 (6) ◽  
pp. 815-825 ◽  
Author(s):  
Li Fan ◽  
Min Hu ◽  
Mingqi Yang
Keyword(s):  
Control Problem ◽  
Translational Control ◽  
Attitude Control ◽  
Formation Flying ◽  
Sliding Mode ◽  
Large Angle ◽  
Translation Control ◽  
Nonlinear Controller ◽  
Content Type ◽  
Hybrid Particle Swarm Optimization

Purpose The purpose of this paper is to develop a theoretical design for the attitude control of electromagnetic formation flying (EMFF) satellites, present a nonlinear controller for the relative translational control of EMFF satellites and propose a novel method for the allocation of electromagnetic dipoles. Design/methodology/approach The feedback attitude control law, magnetic unloading algorithm and large angle manoeuvre algorithm are presented. Then, a terminal sliding mode controller for the relative translation control is put forward and the convergence is proved. Finally, the control allocation problem of electromagnetic dipoles is formulated as an optimization issue, and a hybrid particle swarm optimization (PSO) – sequential quadratic programming (SQP) algorithm to optimize the free dipoles. Three numerical simulations are carried out and results are compared. Findings The proposed attitude controller is effective for the sun-tracking process of EMFF satellites, and the magnetic unloading algorithm is valid. The formation-keeping scenario simulation demonstrates the effectiveness of the terminal sliding model controller and electromagnetic dipole calculation method. Practical implications The proposed method can be applied to solve the attitude and relative translation control problem of EMFF satellites in low earth orbits. Originality/value The paper analyses the attitude control problem of EMFF satellites systematically and proposes an innovative way for relative translational control and electromagnetic dipole allocation.

A finite-time H-infinite adaptive fault-tolerant controller considering time delay for flutter suppression of airfoil flutter

2019 ◽  
Vol 234 (2) ◽  
pp. 293-307
Author(s):  
Gao Ming-Zhou ◽  
Chen Xin-Yi ◽  
Han Rong ◽  
Yao Jian-Yong
Keyword(s):  
Finite Time ◽  
Control Method ◽  
Controller Design ◽  
Fault Tolerant ◽  
Linear Matrix ◽  
Control Methods ◽  
Actuator Faults ◽  
Control Delay ◽  
Modeling Uncertainties ◽  
The Stability

To suppress airfoil flutter, a lot of control methods have been proposed, such as classical control methods and optimal control methods. However, these methods did not consider the influence of actuator faults and control delay. This paper proposes a new finite-time H∞ adaptive fault-tolerant flutter controller by radial basis function neural network technology and adaptive fault-tolerant control method, taking into account actuator faults, control delay, modeling uncertainties, and external disturbances. The theoretic section of this paper is about airfoil flutter dynamic modeling and adaptive fault-tolerant controller design. Lyapunov function and linear matrix inequality are employed to prove the stability of the proposed control method of this paper. The numeral simulation section further proves the effectiveness and robustness of the proposed control algorithm of this paper.

Learning control of flexible manipulator with unknown dynamics

2017 ◽  
Vol 37 (3) ◽  
pp. 304-313 ◽  
Author(s):  
Zhiguang Chen ◽  
Chenguang Yang ◽  
Xin Liu ◽  
Min Wang
Keyword(s):  
Control Method ◽  
Controller Design ◽  
Design Method ◽  
Weight Ratio ◽  
Response Speed ◽  
Dynamic Surface Control ◽  
Flexible Manipulator ◽  
Dynamic Surface ◽  
Content Type ◽  
Surface Control

Purpose The purpose of this paper is to study the controller design of flexible manipulator. Flexible manipulator system is a nonlinear, strong coupling, time-varying system, which is introduced elastodynamics in the study and complicated to control. However, due to the flexible manipulator, system has a significant advantage in response speed, control accuracy and load weight ratio to attract a lot of researchers. Design/methodology/approach Since the order of flexible manipulator system is high, designing controller process will be complex, and have a large amount of calculation, but this paper will use the dynamic surface control method to solve this problem. Findings Dynamic surface control method as a controller design method which can effectively solve the problem with the system contains nonlinear and reduced design complexity. Originality/value The authors assume that the dynamic parameters of flexible manipulator system are unknown, and use Radial Basis Function neural network to approach the unknown system, combined with the dynamic surface control method to design the controller.

scholarly journals Attitude Control of a Single Tilt Tri-Rotor UAV System: Dynamic Modeling and Each Channel's Nonlinear Controllers Design

2013 ◽  
Vol 2013 ◽  
pp. 1-6 ◽  
Author(s):  
Juing-Shian Chiou ◽  
Huu-Khoa Tran ◽  
Shou-Tao Peng
Keyword(s):  
Attitude Control ◽  
Controller Design ◽  
Nonlinear Controller ◽  
Closed Loop System ◽  
Nonlinear Simulation ◽  
Human Thought ◽  
Control Rules ◽  
Nonlinear Controllers ◽  
Nonlinear Mathematical Models ◽  
Raphson Method

This paper has implemented nonlinear control strategy for the single tilt tri-rotor aerial robot. Based on Newton-Euler’s laws, the linear and nonlinear mathematical models of tri-rotor UAVs are obtained. A numerical analysis using Newton-Raphson method is chosen for finding hovering equilibrium point. Back-stepping nonlinear controller design is based on constructing Lyapunov candidate function for closed-loop system. By imitating the linguistic logic of human thought, fuzzy logic controllers (FLCs) are designed based on control rules and membership functions, which are much less rigid than the calculations computers generally perform. Effectiveness of the controllers design scheme is shown through nonlinear simulation model on each channel.

A Nonlinear Controller Design Method for Fuel-Injected Automotive Engines

1988 ◽  
Vol 110 (3) ◽  
pp. 313-320 ◽  
Author(s):  
D. Cho ◽  
J. K. Hedrick
Keyword(s):  
Fuel Injection ◽  
Control Method ◽  
Controller Design ◽  
Sliding Mode ◽  
Design Method ◽  
Model Errors ◽  
Nonlinear Controller ◽  
Engine Model ◽  
Automotive Engines ◽  
On Line

A nonlinear, “sliding mode” fuel-injection controller is designed based on a physically motivated, mathematical engine model. The designed controller can achieve a commanded air-to-fuel ratio with excellent transient properties, which offers the potential for improving fuel economy, torque transients, and emission levels. The controller is robust to model errors as well as to rapidly changing maneuvers of throttle and spark advance. The sliding mode control method offers a great potential for future engine control problems, since: it results in a relatively simple control structure that requires little on-line computing and no table lookups; it is robust to model errors and disturbances; and it can be easily adapted to a family of engines.

scholarly journals Attitude Control with Auxiliary Structure Based on Adaptive Dynamic Programming for Reentry Vehicles

Complexity ◽  
2020 ◽  
Vol 2020 ◽  
pp. 1-19
Author(s):  
Xu Li ◽  
Zhongtao Cheng ◽  
Bo Wang ◽  
Yongji Wang ◽  
Lei Liu
Keyword(s):  
Dynamic Programming ◽  
Attitude Control ◽  
Control Method ◽  
Sliding Mode ◽  
Adaptive Dynamic Programming ◽  
Selection Strategy ◽  
Adaptive Dynamic ◽  
Time Scale Separation ◽  
Reentry Vehicles ◽  
The Stability

This paper presents an attitude control scheme combined with adaptive dynamic programming (ADP) for reentry vehicles with high nonlinearity and disturbances. Firstly, the nonlinear attitude dynamics is divided into inner and outer loops according to the time scale separation and the cascade control principle, and a general sliding mode control method is employed to construct the main controllers for the double loops. Considering the shortage of main controllers in handling nonlinearity and sudden disturbances, an ADP structure is introduced into the outer attitude loop as an auxiliary. And the ADP structure utilizes neural network estimators to minimize the cost function and generate optimal signals through online learning, so as to compensate defect of the main controllers’ adaptability speed and accuracy. Then, the stability is analyzed by the Lyapunov method, and the parameter selection strategy of the ADP structure is derived to guide implementation. In addition, this paper puts forward skills to speed up ADP training. Finally, simulation results show that the control strategy with ADP possesses stronger adaptability and faster response than that without ADP for the nonlinear vehicle system.

scholarly journals A Theoretical Concept of Decoupled Current Control Scheme for Grid-Connected Inverter with L-C-L Filter

2021 ◽  
Vol 11 (14) ◽  
pp. 6256
Author(s):  
Mohamad Amin Ghasemi ◽  
Seyed Fariborz Zarei ◽  
Saeed Peyghami ◽  
Frede Blaabjerg
Keyword(s):  
Control Method ◽  
Controller Design ◽  
Current Control ◽  
System Stability ◽  
State Equations ◽  
Lcl Filter ◽  
Control Scheme ◽  
Grid Connected Inverter ◽  
The Stability ◽  
Grid Side

This paper proposes a nonlinear decoupled current control scheme for a grid-connected inverter with LCL filter. Decoupling the active and reactive current control channels is one of the main demands in the control of inverters. For inverters with an L filter, the decoupling can be achieved by a proper feed-forward of grid voltages. However, the coupling of channels is a complex issue for converters with LCL filters. The resonance mode of the LCL filter may cause instability, which adds more complexity to the analysis. In this paper, state equations of the system are provided, which highlight the coupling between active and reactive currents injected into the grid. Accordingly, a non-linear control scheme is proposed which effectively decouples the channels and dampens the resonant modes of the LCL filter. The stability of the proposed control method is verified by the Lyapunov criterion. Independency of the system stability to the grid-impedance is another feature of the proposed approach. Moreover, only grid-side currents are needed for implementation of the proposed scheme, avoiding the need for additional current sensors for the output capacitor and grid-side inductor. For accurate modelling of the inverter, the computation and PWM sampling delays are included in the controller design. Finally, various case studies are provided that verify the performance of the proposed approach and the stability of the system.

scholarly journals Model predictive control of magnetic levitation system

2020 ◽  
Vol 10 (6) ◽  
pp. 5802
Author(s):  
Lafta E. Jumaa Alkurawy ◽  
Khalid G. Mohammed
Keyword(s):  
Model Predictive Control ◽  
Predictive Control ◽  
Controller Design ◽  
Magnetic Levitation ◽  
Lagrange Function ◽  
Sufficient Conditions ◽  
Nonlinear Controller ◽  
Levitation System ◽  
Magnetic Levitation System ◽  
The Stability

In this work, we suggest a technique of controller design that applied to systems based on nonlinear. We inform the sufficient conditions for the stability of closed loop system. The asymptotic stability of equilibrium and the nonlinear controller can be applied to improvement the stability of Magnetic Levitation system(MagLev). The MagLev nonlinear nodel can be obtained by state equation based on Lagrange function and Model Predictive Control has been used for MagLev system.

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