Shuanghe Yu

Adaptive Autopilot Design of Time-Varying Uncertain Ships With Completely Unknown Control Coefficient

This paper develops an adaptive course controller for time-varying parametric uncertain nonlinear ships with completely unknown time-varying bounded control coefficient. The proposed design method does not require any a priori knowledge of the sign of the unknown time-varying control coefficient. The designed adaptive autopilot can guarantee the regulation of the ship course to any prescribed accuracy and the global uniform ultimate boundedness of all signals in the closed-loop system. The effectiveness of the presented autopilot has been demonstrated in a simulation involving a ship of 45 m in length.

Adaptive Robust Nonlinear Ship Course Control Based on Backstepping and Nussbaum Gain

Abstract Ship steering design presents challenges because the dynamic properties of the vessel itself vazy significantly. This paper develops an adaptive robust nonlineaz course controller for ship steering with unknown parameters, especially completely urdmown control coefficient, and under unknown bounded environrnental disturbances induced by waves, wind, and ocean currents. Based on the incorporation of the Nussbaum-type gain into backstepping algorithm and some technical lemmas, the proposed design method does not require any priori knowledge of the sign of the unknown control coefficient. It is proved that the designed adaptive robust controller can guarantee the uniform ultimate boundedness of all signals in the resulting closed-loop system. The control performance can be guazanteed by an appropriate choice of the design parameters. Simulation results on a 45-meter long ship are presented to validate the proposed controller.

Nonsmooth Finite-Time Control of Uncertain Affine Planar Systems

Nonsmooth finite-time stabilizing control laws have been developed for the double integrator system. The objective of this paper is to further explore the finite-time tracking control problem of a general form of uncertain second-order affine nonlinear system with the new forms of terminal sliding mode (TSM). Discontinuous and continuous finite-time controllers are also developed respectively without the singularity problem. Complete robustness can be acquired with the former, and enhanced robustness compared with the conventional boundary layer method can be expressed as explicit bounded function with the latter. Simulation results on the stabilizing and tracking problems are presented to demonstrate the effectiveness of the control algorithms

An enhanced back propagation algorithm for parameter estimation of rational models

In this study, an enhanced back propagation (EBP) algorithm for estimating the parameters of non-linear rational models is presented to improve convergence rate. The effectiveness of the EBP algorithm is initially demonstrated by simulations.

Consensus of linear multi-agent systems via reduced-order observer

This paper is concerned with the consensus problem for continuous time linear multi-agent systems with directed communication topology. An estimation error dynamic is proposed to design the reduced-order observer for dealing with unknown coefficient matrices. To guarantee the consensus, control protocols based on the reduced-order observer are designed to utilize the relative outputs of neighboring agents whose communication topology contains a directed spanning tree. Then the algorithms are extended to the model reference consensus case, where the case of zero control input for reference node is not assumed. Numerical examples are given to illustrate the effectiveness of proposed approaches.

Asymptotic Average Consensus of Continuous-time Multi-agent Systems with Dynamically Quantized Communication

Abstract This paper focuses on the consensus problem of continuous-time single-integrator and double-integrator multi-agent systems (MASs) with dynamically quantized information transmission. The connected undirected graphs are utilized to characterize the interaction topology between the agents. Dynamic quantizers are firstly introduced for a linear asymptotically stable system with a less conservative update interval. Through certainty equivalent quantized feedback controller and state transformation, the consensus problems of single-integrator and double-integrator MASs are then converted to the linear asymptotic stabilization problem, meanwhile the proposed dynamic quantization strategy is naturally applied to MAS to achieve asymptotic quantized average consensus. Finally, numerical examples are provided to illustrate the effectiveness of the theoretical results.

Continuous Finite-Time Terminal Sliding Mode IDA-PBC Design for PMSM with the Port-Controlled Hamiltonian Model

Finite-time control scheme for speed regulation of permanent magnet synchronous motor (PMSM) is investigated under the port-controlled Hamiltonian (PCH), terminal sliding mode (TSM), and fast TSM stabilization theories. The desired equilibrium is assigned to the PCH structure model of PMSM by maximum torque per ampere (MTPA) principle, and the desired Hamiltonian function of state error is constructed in the form of fractional power structure as TSM and fast TSM, respectively. Finite-time TSM and fast TSM controllers are designed via interconnection and damping assignment passivity-based control (IDA-PBC) methodology, respectively, and the finite-time stability of the desired equilibrium point is also achieved under the PCH framework. Simulation results validate the improved performance of the presented scheme.

Adaptive Control for a Class of Time-varying Uncertain Nonlinear Systems

This paper develops an adaptive nonlinear control scheme for time-varying parametric uncertain nonlinear system with completely unknown time-varying bounded control coefficient. The proposed design method does not require any a priori knowledge of the sign of the unknown time-varying control coefficient, based on incorporating Nussbaum function gain and smooth projection algorithm into backstepping. It is proved that the designed adaptive nonlinear controller can guarantee the stability and the global uniform ultimate boundedness of all signals of the resulting closed-loop system. The control performances of the system can be guaranteed by an appropriate choice of the design parameters. Simulation studies are included to illustrate the feasibility and effectiveness of the presented approach