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.

A novel robust finite-time tracking control of uncertain robotic manipulators with disturbances

2020 ◽  
pp. 107754632098244
Author(s):  
Hamid Razmjooei ◽  
Mohammad Hossein Shafiei ◽  
Elahe Abdi ◽  
Chenguang Yang
Keyword(s):  
Finite Time ◽  
Control Method ◽  
Sliding Mode ◽  
Robotic Manipulators ◽  
Sliding Mode Controller ◽  
Time Varying ◽  
State Variables ◽  
Terminal Sliding Mode ◽  
Control Laws ◽  
Finite Time Boundedness

In this article, an innovative technique to design a robust finite-time state feedback controller for a class of uncertain robotic manipulators is proposed. This controller aims to converge the state variables of the system to a small bound around the origin in a finite time. The main innovation of this article is transforming the model of an uncertain robotic manipulator into a new time-varying form to achieve the finite-time boundedness criteria using asymptotic stability methods. First, based on prior knowledge about the upper bound of uncertainties and disturbances, an innovative finite-time sliding mode controller is designed. Then, the innovative finite-time sliding mode controller is developed for finite-time tracking of time-varying reference signals by the outputs of the system. Finally, the efficiency of the proposed control laws is illustrated for serial robotic manipulators with any number of links through numerical simulations, and it is compared with the nonsingular terminal sliding mode control method as one of the most powerful finite-time techniques.

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.

Deterministic robust control design for an iron core linear drive including second-order electrical dynamics

2018 ◽  
Vol 232 (8) ◽  
pp. 951-962 ◽  
Author(s):  
Fernando Villegas ◽  
Rogelio Hecker ◽  
Miguel Peña
Keyword(s):  
Robust Control ◽  
Tracking Error ◽  
Second Order ◽  
Iron Core ◽  
State Variables ◽  
State Transformation ◽  
Robust Controller ◽  
Current Controller ◽  
Bounded State ◽  
Robust Control Design

This work proposes a deterministic robust controller to improve tracking performance for a linear motor, taking into account the electrical dynamics imposed by a commercial current controller. The design is split in two parts by means of the backstepping technique, in which the first part corresponds to a typical deterministic robust controller, neglecting the electrical dynamics. In the second part, a second-order electrical dynamics is considered using a particular state transformation. There, the proposed control law is composed of a term to compensate the known part of the model and a robust control term to impose a bound on the effect of uncertainties on tracking error. Stability and boundedness results for the complete controller are given. To this effect, a general result on boundedness and stability of nonlinear systems with conditionally bounded state variables is derived first. Finally, experimental results for the complete controller show an improvement on tracking error of up to 31.7% when compared with the results from the typical controller that neglects the electrical dynamics.

scholarly journals Adaptive Neural Control for Nonaffine Pure-Feedback System Based on Extreme Learning Machine

2019 ◽  
Vol 2019 ◽  
pp. 1-13
Author(s):  
Chenyang Xu ◽  
Humin Lei ◽  
Jiong Li ◽  
Jikun Ye ◽  
Dongyang Zhang
Keyword(s):  
Extreme Learning Machine ◽  
Neural Control ◽  
Control Method ◽  
Tracking Error ◽  
Adjustment Process ◽  
Equivalent Transformation ◽  
State Variables ◽  
Feedback Systems ◽  
Adaptive Neural Control ◽  
Learning Machine

For nonaffine pure-feedback systems, an adaptive neural control method based on extreme learning machine (ELM) is proposed in this paper. Different from the existing methods, this scheme firstly converts the original system into a nonaffine system containing only one unknown term by equivalent transformation, thus avoiding the cumbersome and complex indirect design process of traditional backstepping methods. Secondly, a high-performance finite-time-convergence-differentiator (FD) is designed, through which the system state variables and their derivatives are accurately estimated to ensure the control effect. Thirdly, based on the implicit function theorem, the ELM neural network is introduced to approximate the uncertain items of the system, which simplifies the repeated adjustment process of the network training parameters. Meanwhile, the minimum learning parameter algorithm (MLP) is adopted to design the adaptive law for the norm of the network weight vector, which significantly reduces calculations. And it is theoretically proved that the closed-loop control system is stable and the tracking error is bounded. Finally, the effectiveness of the designed controller is verified by simulation.

scholarly journals New Integrated Guidance and Control of Homing Missiles with an Impact Angle against a Ground Target

2018 ◽  
Vol 2018 ◽  
pp. 1-10 ◽  
Author(s):  
Shengjiang Yang ◽  
Jianguo Guo ◽  
Jun Zhou
Keyword(s):  
Control System ◽  
Control Method ◽  
Sliding Mode ◽  
Lyapunov Stability Theory ◽  
Impact Angle ◽  
Guidance And Control ◽  
Ground Target ◽  
Integrated Guidance And Control ◽  
And Control ◽  
The Impact

A new integrated guidance and control (IGC) law is investigated for a homing missile with an impact angle against a ground target. Firstly, a control-oriented model with impact angle error of the IGC system in the pitch plane is formulated by linear coordinate transformation according to the motion kinematics and missile dynamics model. Secondly, an IGC law is proposed to satisfy the impact angle constraint and to improve the rapidity of the guidance and control system by combining the sliding mode control method and nonlinear extended disturbance observer technique. Thirdly, stability of the closed-loop guidance and control system is proven based on the Lyapunov stability theory, and the relationship between the accuracy of the impact angle and the estimate errors of nonlinear disturbances is derived from stability of the sliding mode. Finally, simulation results confirm that the proposed IGC law can improve the performance of the missile guidance and control system against a ground target.

Control Algorithm Study on Cantilever Machine Teaching-Playback

2014 ◽  
Vol 635-637 ◽  
pp. 1212-1215
Author(s):  
Ruo Han Liu ◽  
Chun Hua Li
Keyword(s):  
Control System ◽  
Intelligent Control ◽  
Control Algorithm ◽  
Control Method ◽  
Tracking Error ◽  
Cutting Parameters ◽  
Configuration Software ◽  
Monitoring Site ◽  
Software Monitoring ◽  
Operation Panel

In order to realize intelligent control, the cutting trajectory of TBM research machine adopts the principle of teaching and reappearing cutting trajectory control method, combining with the control system of teaching and reappearing and SIMATIC C7, operation interface is realized by using configuration software monitoring, monitoring site visually through the operation panel parameters change, timely adjust the cutting parameters. The experimental results show that the tracking error within the scope of the permit. The method to improve the intelligence of machine cutting control provides a reference basis.

Design of Missile Longitudinal Control System Based on Backstepping Control

2014 ◽  
Vol 496-500 ◽  
pp. 1401-1406
Author(s):  
Mei Hong Li ◽  
Jian Yin ◽  
Xue Yang Sun ◽  
Jin Xiang Xu ◽  
Mei Mei Zhang
Keyword(s):  
Control System ◽  
Control Method ◽  
Input Saturation ◽  
Lyapunov Stability Theory ◽  
Feedback System ◽  
Backstepping Control ◽  
Control Input ◽  
Backstepping Method ◽  
Longitudinal Control ◽  
And Control

Missile control system is not block strict feedback system which is suitable to use backstepping method. So in this paper, a backstepping control method is proposed to design a missile longitudinal autopilot and is proved to be asymptotically stable by Lyapunov stability theory. The simulation results show that the designed system can still track commands quickly and accurately and is robust with aerodynamic perturbation and control input saturation.

scholarly journals Adaptive Sliding Mode Control for a Class of Manipulator Systems with Output Constraint

Complexity ◽  
2021 ◽  
Vol 2021 ◽  
pp. 1-7
Author(s):  
Guangshi Li
Keyword(s):  
Sliding Mode Control ◽  
Control Method ◽  
Sliding Mode ◽  
Tracking Error ◽  
Lyapunov Stability Theory ◽  
Adaptive Sliding Mode Control ◽  
Compact Set ◽  
Adaptive Sliding Mode ◽  
Mode Control ◽  
System Output

In this paper, an adaptive sliding mode control method based on neural networks is presented for a class of manipulator systems. The main characteristic of the discussed system is that the output variable is required to keep within a constraint set. In order to ensure that the system output meets the time-varying constraint condition, the asymmetric barrier Lyapunov function is selected in the design process. According to Lyapunov stability theory, the stability of the closed-loop system is analyzed. It is demonstrated that all signals in the resulted system are bounded, the tracking error converges to a small compact set, and the system output limits in its constrained set. Finally, the simulation example is used to show the effectiveness of the presented control strategy.

Active Vibration Control Method for Space Mechanical Structure with Piezostacks

2013 ◽  
Vol 198 ◽  
pp. 433-438
Author(s):  
Andrzej Piotr Koszewnik
Keyword(s):  
Control System ◽  
Vibration Control ◽  
Control Method ◽  
Active Vibration Control ◽  
Three Dimensional ◽  
Control Laws ◽  
Distributed Parameters ◽  
Short Period ◽  
Lqr Controller ◽  
Active Vibration

Mechanical structures are spatial, three-dimensional (3D) systems of distributed parameters. They present quite complicated plants, if methods of control systems theory are applied. The design process of the vibration control system for such plants is extremely difficult and requires an extensive heuristic knowledge. The subject of the control system is to eliminate the vibrations of the free end at the plane parallel to the foundation Similar problems are met, when the stabilization of robot arms, antennas, satellite solar batteries or slender skyscrapers is considered. In the paper we have presented the 3D bar structure with sticked parallel two piezo-stacks into bars. Recall piezo-elements are actuators, but sensors are two eddy-current sensors located in near free end the structure in perpendicular directions X and Y. Thus the whole structure is TITO (Two Input Two Output) system. For such system the control law was designed with used LQR controller. Above controller was designed for coupled and decoupled system also. In both case a correct damp and very short period of the vibration were criteria to choose the controller parameters. All investigations were carried out in two steps. In the first step control laws were designed in computer simulation. In the second step these control laws were verified experimentally on the laboratory stand by using DSP. Finally, desired control laws were compared.

Automatically Controlled Anti-Collision Manoeuvre and its Numerical Simulation with Disturbances

2013 ◽  
Vol 210 ◽  
pp. 156-165
Author(s):  
Jerzy Graffstein
Keyword(s):  
Numerical Simulation ◽  
Control System ◽  
Automatic Control ◽  
Numerical Simulations ◽  
Abrupt Change ◽  
State Variables ◽  
Control Laws ◽  
Analysis Of Results ◽  
System Robustness ◽  
And Control

The article presents the discussion focused on specific features of the problem of flying objects motion when performing an example of anti collision manoeuvre. To realise this task, the structure of automatic control system with appropriate control laws are proposed. The nature of discussed manoeuvre needs the appropriate numerical method for computing desired values of state variables for subsequent phases of objects motion. These values are obtained adequately for their roles in several phases of motion. Numerical simulations are completed for the aircraft performing the anti collision manoeuvre consisted in abrupt change of yaw. Objects behaviour was tested in case of motion affected by disturbances. The analysis of results obtained by numerical simulations makes possible conclusions on stability of objects motion and control system robustness to assumed kind and level of disturbances.

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