Platoon Formation Control of USVs With Output Tracking Error Constraints

2018 ◽  
Author(s):  
Qingzhao Ye ◽  
Shude He ◽  
Shi-Lu Dai
Keyword(s):  
Formation Control ◽  
Tracking Error ◽  
Output Tracking

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.

Output tracking control of high-order nonlinear systems with dynamic uncertainties

2019 ◽  
Vol 42 (8) ◽  
pp. 1511-1520
Author(s):  
Zong-Yao Sun ◽  
Yu-Jie Gu ◽  
Qinghua Meng ◽  
Wei Sun ◽  
Zhen-Guo Liu
Keyword(s):  
Nonlinear Systems ◽  
Tracking Control ◽  
Tracking Error ◽  
High Order ◽  
Approximation Technique ◽  
Zero Dynamic ◽  
Adding A Power Integrator ◽  
Output Tracking ◽  
Output Tracking Control ◽  
Dynamic Uncertainties

This paper investigates the output tracking control problem for a class of nonlinear systems with zero dynamic. On the basis of adding a power integrator method and approximation technique, an appropriate controller is proposed to guarantee that the tracking error turns to a preassigned neighborhood of the origin. The systems under investigation allow unmeasurable dynamic uncertainties, unknown nonlinear functions and unknown high-order terms. As an application, two examples are provided to illustrate the effectiveness of a control strategy.

scholarly journals Adaptive output regulation for a class of nonlinear systems with guaranteed transient performance

2019 ◽  
Vol 42 (6) ◽  
pp. 1180-1190
Author(s):  
Weijie Sun ◽  
Zhenhua Zhu ◽  
Jianglin Lan ◽  
Yunjian Peng
Keyword(s):  
Nonlinear Systems ◽  
Tracking Error ◽  
High Gain ◽  
Output Regulation ◽  
Control Law ◽  
Stabilization Problem ◽  
Transient Performance ◽  
Adaptive Stabilization ◽  
Output Tracking ◽  
Output Constraints

This paper is dedicated to adaptive output regulation for a class of nonlinear systems with asymptotic output tracking and guarantee of prescribed transient performance. With the employment of internal model principle, we first transform this problem into a specific adaptive stabilization problem with output constraints. Then, by integrating the time-varying Barrier Lyapunov Function (BLF) technique together with the high gain feedback method, we develop an output-based control law to solve the constrained stabilization problem and consequently confine the output tracking error to a predefined arbitrary region. The output-based control law enables adaptive output regulation in the sense that, under unknown exosystem dynamics, all the closed-loop system signals are bounded whilst the controlled output constraints are not violated. Finally, efficacy of the proposed design is illustrated through a simulation example.

Indirect Neural Network Adaptive Robust Control of Linear Motor Drive System

2002 ◽  
Author(s):  
J. Q. Gong ◽  
Bin Yao
Keyword(s):  
Neural Network ◽  
Robust Control ◽  
Tracking Error ◽  
Linear Motor ◽  
Adaptive Robust Control ◽  
Operating Conditions ◽  
Tracking Performance ◽  
Motor Drive ◽  
Output Tracking ◽  
On Line

In this paper, an indirect neural network adaptive robust control (INNARC) scheme is developed for the precision motion control of linear motor drive systems. The proposed INNARC achieves not only good output tracking performance but also excellent identifications of unknown nonlinear forces in system for secondary purposes such as prognostics and machine health monitoring. Such dual objectives are accomplished through the complete separation of unknown nonlinearity estimation via neural networks and the design of baseline adaptive robust control (ARC) law for output tracking performance. Specifically, recurrent neural network (NN) structure with NN weights tuned on-line is employed to approximate various unknown nonlinear forces of the system having unknown forms to adapt to various operating conditions. The design is actual system dynamics based, which makes the resulting on-line weight tuning law much more robust and accurate than those in the tracking error dynamics based direct NNARC designs in implementation. With a controlled learning process achieved through projection type weights adaptation laws, certain robust control terms are constructed to attenuate the effect of possibly large transient modelling error for a theoretically guaranteed robust output tracking performance in general. Experimental results are obtained to verify the effectiveness of the proposed INNARC strategy. For example, for a typical point-to-point movement, with a measurement resolution level of ±1μm, the output tracking error during the entire execution period is within ±5μm and mainly stays within ±2μm showing excellent output tracking performance. At the same time, the outputs of NNs approximate the unknown forces very well allowing the estimates to be used for secondary purposes such as prognostics.

Output-Boundary Regulation for Nonlinear Nonminimum-Phase Systems

2016 ◽  
Author(s):  
Arom Boekfah ◽  
Santosh Devasia
Keyword(s):  
State Transition ◽  
Tracking Error ◽  
System State ◽  
Full System ◽  
Nonminimum Phase ◽  
Output Tracking ◽  
Output Error ◽  
Nonminimum Phase Systems ◽  
Phase Systems ◽  
Boundary Regulation

Exact output tracking requires preview information of the desired output for nonminimum-phase systems. For situations when preview information is not available, this article proposes an output-boundary regulation (OBR) approach that maintains the output-tracking error within prescribed bounds for nonlinear nonminimum-phase systems. OBR transitions the output-tracking error to zero whenever the output error reaches a set magnitude using polynomial output trajectories for each transition. The main contribution is to show that an output-transition-based OBR (O-OBR, which uses post-actuation input to transition the system state after the output-error transition is completed) can enable OBR of more aggressive output trajectories when compared to a state-transition-based OBR (S-OBR) that transitions the full system state and therefore achieves the output transition as well. Results from an example simulation system is used to illustrate the proposed OBR approach and comparatively evaluate the S-OBR and O-OBR approaches, which show that, for the example system, the O-OBR can track 3 times faster desired output trajectory than the S-OBR approach.

Error-based output tracking for a one-dimensional wave equation with harmonic type disturbance

2020 ◽  
Vol 37 (4) ◽  
pp. 1447-1467
Author(s):  
Ziqing Tian ◽  
Xiao-Hui Wu
Keyword(s):  
Wave Equation ◽  
Closed Loop ◽  
Tracking Error ◽  
Difficult Case ◽  
Closed Loop System ◽  
One Dimensional ◽  
Output Tracking ◽  
Planning Approach ◽  
Uniformly Bounded ◽  
Dimensional Wave

Abstract In this paper, we consider output tracking for a one-dimensional wave equation, where the boundary disturbances are either collocated or non-collocated with control. The regulated output and the control are supposed to be non-collocated with control, which represents a difficult case for output tracking of PDEs. We apply the trajectory planning approach to design an observer, in terms of tracking error only, to estimate both states of the system and the exosystem from which the disturbances are produced. An error-based feedback control is proposed by solving a standard regulator equation. It is shown that (a) the closed-loop system is uniformly bounded whenever the exosystem is bounded; (b) when the disturbance is zero, the closed-loop is asymptotically stable; and (c) the tracking error converges to zero asymptotically as time goes to infinity. Numerical simulations are performed to validate the effectiveness of the proposed control.

Distributed Adaptive Formation Control for Underactuated Quadrotors with Guaranteed Performances

2021 ◽  
Author(s):  
Xingling Shao ◽  
Xiaohui Yue ◽  
Jun Liu
Keyword(s):  
Formation Control ◽  
Estimation Error ◽  
Tracking Error ◽  
Synchronization Errors ◽  
Control Scheme ◽  
Transient Solutions ◽  
Uncertain Disturbances ◽  
Formation Pattern ◽  
Consensus Strategy ◽  
Error Dynamics

Abstract This paper investigates a distributed adaptive formation control problem for underactuated quadrotors with guaranteed performances. To ensure a robust and stable formation pattern with predefined behavior bounds, by transforming the original constrained formation synchronization error dynamics into an equivalent unconstrained one, a prescribed performance mechanism is introduced in the translational loop to render the formation regulation as a prior. Based on the graph theory and Lyapunov stability analysis, a state estimator-based minimal learning parameter (SE-MLP) neuroadaptive consensus strategy is developed for follower quadrotors to achieve a distributed cooperative formation with prescribed tracking abilities via exchanging local information with neighbors. The presented control scheme has the following salient merits: 1) the formation synchronization errors can be guaranteed within pre-assigned bounds with desired transient behaviors despite of uncertain disturbances; 2) by using a state estimation error to update neural network (NN) parameters, rather than the tracking error that widely applied in traditional NN approximators, and with the help of MLP technique, the proposed SE-MLP observer capable of decreasing the computational complexity can achieve a fast identification of lumped disturbances without causing high-frequency oscillations even using a large adaptive gain, and the transient solutions of L 2 norm of the differential of neural weights are established to illustrate the mechanism of SE-MLP observer in reducing chattering behaviors. Simulation results are given to validate the efficiency of developed technique.

Robust Control for a Class of Nonlinear Systems Based on Backstepping

2011 ◽  
Vol 50-51 ◽  
pp. 110-114
Author(s):  
Nai Bao He ◽  
Qian Gao
Keyword(s):  
Robust Control ◽  
Tracking Error ◽  
Small Neighborhood ◽  
Control Law ◽  
Closed Loop System ◽  
Unknown Parameters ◽  
Feedback Form ◽  
Output Tracking ◽  
Adaptive Parameter ◽  
Adaptive Parameter Control

Based on coordinate transform, the paper deduced the principle with which Chua’s chaotic system can be translated into the so-called general strict-feedback form. Combining the backstepping method with robust control technology, an adaptive parameter control law is developed and thus the output tracking is successfully accomplished for the system with unknown parameters and dynamic uncertainties. It is proved that all states of the closed-loop system are globally uniformly　ultimately bounded, and lead the system tracking error to a small neighborhood. Finally simulation results are provided to show the effectiveness of the proposed approach.

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