International Journal of Control, Automation and Systems

In most literature related to reset control, the reset actions are triggered by continuous monitoring triggering reset conditions, which is not suitable for computer-based implementation. This paper considers periodic triggering reset control, where the reset actions are only triggered at periodically sampling instants. Hybrid system approach is given to analyze the asymptotic stability and L 2 gain property, and less conservative switched system approach is presented for asymptotic stability analysis. The comparison of the two approaches is discussed. Moreover, novel reset conditions are given to improve the overshoot performance. Simulations are presented to support our results.

This paper presents a rank-based formation for swarm agents based on potential functions, where the proposed methods use the relative positions of two neighboring agents. The formation scheme of conventional swarm systems requires communication between agents and a central computer to get the positions of all swarm agents. In the study, as opposed to previous studies, the formation scheme uses the relative positions of two neighboring agents in a local coordinate system. In addition, it introduces a singular agent association that considers only the relative position between an agent and its neighboring agents, instead of multiple associations among all information about all agents. Extensive simulation and experiment result show that the proposed approach verifies the viability and effectiveness of the proposed formation.

Định vị đồng thời và lập bản đồ (SLAM) là một chủ đề quan trọng trong robot thông minh. Trong bài báo này, một thuật toán theo dõi robot trong SLAM với bộ lọc Kalman không mùi Masreliez-Martin (MMUKF) được đề xuất. Mô hình động học của robot dựa trên các đặc điểm của SLAM được sử dụng làm phương trình trạng thái để mô hình hóa chuyển động của robot, và các phương trình đo lường được suy diễn bằng cách tuyến tính hóa mô hình chuyển động. Tiếp theo, hiệp phương sai của tiếng ồn quy trình được ước lượng với một yếu tố thích nghi để cải thiện hiệu suất theo dõi trong MMUKF. Cuối cùng, MMUKF được sử dụng để ước lượng vị trí của robot và các đối tượng chú thích. Thuật toán đề xuất có thể hoàn thành việc theo dõi robot với độ chính xác tốt, và đạt được ước lượng trạng thái đáng tin cậy trong SLAM. Kết quả mô phỏng cho thấy tính hợp lệ của thuật toán đề xuất.

In this paper, we investigate the finite-time H∞ control problem for the class of cascade nonlinear switched systems consisting of two parts which are also switched systems using a state-dependent switching method. The state feedback controller and the switching law are designed respectively, which guarantees that the corresponding closed-loop system is finite-time bounded and has a prescribed H∞ performance index; the corresponding sliding motion problems are also considered. Sufficient conditions for the solvability of the problem are obtained. A numerical example is given to demonstrate the validity of the proposed approach.

In this paper, we propose a new approach to ship berthing by using autonomous tugboats. This approach overcomes the nominal effectiveness problem of actuators at slow speed maneuvering to improve the ship operation in the harbor area. The proposed SMC gave us a sliding mode control law that guarantees position tracking with desired velocity in the presence of environmental disturbances. The thrust allocation problem is solved by using a redistributed pseudo-inverse (RPI) algorithm to determine the thrust and direction of each individual tugboat. The main goal of RPI method is to minimize the power supplied to tugboats and increase their controllability. The proposed approach has been simulated on a model of a supply vessel with excellent results.

An appropriate setting of eventual controller parameters for a derived controller structure represents an integral part of many control design approaches for dynamical systems. This contribution is aimed at a practically applicable and uncomplicated controller tuning method for linear time-invariant time delay systems (LTI-TDSs). It is based on placing the dominant poles as well as zeros of the given infinite-dimensional feedback control system by matching them with the desired ones given by known dynamical properties of a simple fixed finite-dimensional model. The desired placing is done successively by applying the Quasi-Continuous Shifting Algorithm (QCSA) first such that poles and zeros are forced to be as close as possible to those of the model. Concurrently, rests of both system spectra are shifted to the left as far as possible to minimize the spectral abscissa. The obtained results are then enhanced by a non-convex optimization technique applied to a selected objective function reflecting the distance of desired model roots from the eventual system ones and the spectral abscissae. Retarded LTI-TDS are primarily considered; however, systems with neutral delays are touched as well. The efficiency of the proposed method is proved via numerical examples in Matlab/Simulink environment. Some drawbacks and possible improvements or extensions of the algorithm for the future research are also concisely suggested to the reader.

This paper investigates two finite-time controllers for the attitude tracking control of the spacecraft based on the quaternion by terminal sliding mode control. Because quaternion is unable to represent the set of attitudes both globally and uniquely, it can result in unwinding. Unwinding makes a spacecraft perform an unnecessary large-angle maneuver when a small-angle maneuver in the opposite rotational direction is sufficient to achieve the objective. The first controller converges to the equilibrium without singularity in finite time, while the second one converges to the region near the equilibrium without singularity, chattering and unwinding in finite time. Saturation function is introduced to the first controller to eliminate singularity, while a novel fast terminal sliding mode control is introduced to the second controller to eliminate singularity and unwinding. Theoretical analysis shows that the controllers can make the spacecraft follow a time-varying reference attitude signal in finite time and guarantee the stability of the overall closed-loop system. Numerical simulations also demonstrate the effectiveness of the proposed control schemes.

This paper is concerned with the stability analysis of Takagi-Sugeno (T-S) fuzzy systems with time varying delays in a given range. The delay partitioning approach is proposed to solving the problem of stability analysis for T-S fuzzy systems. By employing a new type of Lyapunov-Krasovskii functionals, delay-range-dependent stability criteria are derived for T-S fuzzy systems. The idea of the approach is that the delay interval is uniformly divided into N segments with N a positive integer, and a proper Lyapunov-Krasovskii functional is chosen with different weighted matrices corresponding to different segments in the Lyapunov-Krasovskii functional. All the sufficient criteria are established in terms of linear matrix inequalities (LMIs), which can be solved efficiently by using the LMI algorithm. Finally, numerical example is given to illustrate the less conservatism of the proposed method.

One of the problems of the inverse model-based control techniques is the stability of the identified inverse model after the estimation process by the recursive least square (RLS) method. One solution is to use the all pass filtering (APF) technique to transform non-minimum phase models into minimum phase models [9]. However, there are several cases not cured by the all pass filtering method when the all pass filter algorithm is implemented on the hardware. In this paper, an improved version of the all pass filtering technique is presented to deal with the non-minimum phase models. The factorized APF (fAPF) technique for non-minimum phase models is presented to suggest a simple solution. A simple method for avoiding the calculation of complex numbers is also presented for the easy implementation. Several examples are given to support the proposal.