TRƯỜNG ĐẠI HỌC HÀNG HẢI VIỆT NAM

VIETNAM MARITIME UNIVERSITY

Observer-based Trajectory Tracking for a Class of Underactuated Lagrangian Systems Using Higher-order Sliding Modes

Trajectory tracking control of an underactuated mechanical system is a challenging task when tracking errors of all the system coordinates need to be minimized, while the number of control inputs is limited. This paper addresses the observer-based multivariable control of a class of nonlinear, underactuated Lagrangian systems with application to trajectory tracking and sway control of a 3D overhead gantry crane subject to Coulomb friction. A second-order sliding mode observer is proposed for the estimation of velocities.

On sliding dynamics bounding for discrete-time systems with state delay and disturbances

This paper addresses the problem of bounding the reachable set of the sliding dynamics in discrete-time systems subject to time-varying state delay and bounded external disturbances. The sliding motion is determined from the equivalent dynamics chosen from a desired eigen-structure via the pole placement technique. New delay-dependent conditions are derived to guarantee that the trajectories in the sliding mode are prescribed in an ellipsoid with a minimal bound on each coordinate.

FPGA-based fuzzy sliding mode control for sensorless PMSM drive

This paper presents an observer-based fuzzy sliding mode controller for sensorless Permanent Magnet Synchronous Motor (PMSM) drive based on the Field Programmable Gate Array (FPGA) technology. For enhancement of robustness, a sliding mode observer (SMO) is proposed to estimate first the current and back electromotive force (EMF), then to derive the flux angle. These estimated values together with the computed rotor speed of the motor are fed back for the control purpose in both the current loop and the speed loop.

Improved Reachable Set Bounding for Linear Systems with Discrete and Distributed Delays

This paper addresses the problem of reachable set bounding for linear systems in the presence of both discrete and distributed delays. The time delay is assumed to be differentiable and vary within an interval.

Reachable Set Bounding for Linear Discrete-Time Systems with Delays and Bounded Disturbances

This paper addresses the problem of reachable set bounding for linear discrete-time systems that are subject to state delay and bounded disturbances. Based on the Lyapunov method, a sufficient condition for the existence of ellipsoid-based bounds of reachable sets of a linear uncertain discrete system is derived in terms of matrix inequalities. Here, a new idea is to minimize the projection distances of the ellipsoids on each axis with different exponential convergence rates, instead of minimization of their radius with a single exponential rate.

Robust exponential stabilization of underactuated mechanical systems in the presence of bounded disturbances using sliding mode control

This article addresses the robust exponential stabilization problem of underactuated mechanical systems in the presence of bounded external disturbances using sliding mode control. Based on the Lyapunov method, a sufficient condition for the existence of the smallest possible ball which bounds the reduced-order sliding mode dynamics, is first derived in terms of linear matrix inequality (LMI). A sliding mode controller is then synthesized to guarantee that system state trajectories are exponentially convergent to another ball with a prespecified  onvergence rate.

Adaptive fuzzy sliding mode control for uncertain nonlinear underactuated mechanical systems

Sliding mode control has been shown to be a robust and effective control approach for stabilization of nonlinear systems. However the dynamic performance of the controller is a complex function of the system parameters, which is often uncertain or partially known. This paper presents an adaptive fuzzy sliding mode control for a class of underactuated nonlinear mechanical systems. An adaptive fuzzy system is used to approximate the uncertain parts of the underactuated system. The adaptive law is designed based on the Lyapunov method.

APRC-Based Decentralised Model Predictive Control for Parallel Splitting Systems with a Matrix Annihilation

A decentralized model predictive control strategy for interconnected process systems having parallel-splitting structure based on the asymptotically positive realness constraint (APRC) is presented in this paper. Parallel masking and transform descriptor approaches have been employed in previous work for this type of interconnection processes. A robust control perspective has been brought to light in this work to resolve the issue of multiple subprocess parallelised-ly decoupled in a mixed connection configuration of dynamically coupled units.

Partial state estimation for linear systems with output and input time delays

This paper deals with the problem of partial state observer design for linear systems that are subject to time delays in the measured output as well as the control input. By choosing a set of appropriate augmented Lyapunov-Krasovskii functionals with a triple-integral term and using the information of both the delayed output and input, a novel approach to design a minimal-order observer is proposed to guarantee that the observer error is ε-convergent with an exponential rate.

Offshore container crane systems with robust optimal sliding mode control

Open-sea ship-to-ship transfer operation is an alternative way to avoid port congestion. This process involves a relatively small vessel which transports containers between the harbour and a large cargo ship equipped with a container crane. However, the presence of disturbances and uncertainties caused by harsh open-sea conditions can produce an excessive sway to the hoisting ropes of the crane system.