مجله کنترل
سال سیزدهم شماره 1 (بهار 1398)

In this paper a finite-time flocking of multi-agent system with input saturation is investigated. By introducing a new control protocol, it is show that speed and position of agents with double-integrator dynamics converge to the speed and position of leader in finite time. It is assumed that the graph between the agents is connected and that at least one agent is informed of the leader speed and position. It is shown that the agents do not collide under this control protocol and the graph remains connected. Further, conditions are provided by which the control signal level remains less than the limiting saturation range.

This paper reviews the service quality management control and upgrade as well as the communications and information technology enhancement. The purpose of this research is the control and improvement of the service quality management as well as the enhancement of the parent telecommunications network of I.R.Iran that finally, taking the specific conditions into consideration, the quality management service model of the telecommunications parent network of Iran will precisely be used as the whole in the format of the communications and information technology enhancement model after identifying and specifying the levels of the relationships existing among the models, and the standards of the communications and information technology management. The study shows developing such a model in the industry of ICT with emphasis and establishment in the parent telecommunications network of Iran, benefit of human capital with the latest technology and presenting modern services to the customers, the service quality management will be upgraded and will lead to the improvement in quality management in the field of ICT.

Stability and stabilization of impulsive switched system have been considered in recent decades, but there are some issues that are not yet fully addressed such as actuator saturation. This paper deals with expo-nential stabilization for a class of nonlinear impulsive switched systems with different types of non-vanishing uncertainties under the norm-bounded control input. Due to the constrained control signal, the local stabilization is here considered. To establish local stabilization criteria, at first, based on multiple Lyapunov functions technique and minimum dwell-time approach, sufficient conditions for a more gen-eral model of impulsive switched systems are proposed. These conditions are also local which increases the chances of achieving the goals compared to existing global techniques. Also, unlike conventional mul-tiple Lyapunov function techniques, this paper considers converging to a sufficient small ultimate bound because of non-vanishing property of the uncertainties. Secondly, the proposed conditions for the general model are applied to the given system and the sufficient stability conditions are formed into linear and bi-linear matrix inequalities. After these, to achieve the parameters of stabilizing control signal along with the largest convergence area and smallest ultimate bound, an optimization problem is proposed. Finally, some illustrative numerical examples are presented to demonstrate the proposed approach.

This paper has been devoted to the design of a distributed consensus control for a class of uncertain nonlinear multi-agent systems in the strict-feedback form. The communication between the agents has been described by a directed graph. Radial-basis function neural networks have been used for the approximation of the uncertain and heterogeneous dynamics of the followers as well as the effect of the neighbors of each agent in the multi-agent system. Then, the proposed scheme based on the dynamic surface control approach has been presented. Stability analysis of the closed-loop system shows that all the signals of the closed-loop system are uniformly ultimately bounded. The proposed scheme solves the consensus problem in the multi-agent systems with uncertain dynamics and avoids the "explosion of complexity" problem. The simulation results of the proposed approach are presented on a group of single-link robots with uncertain dynamics including four followers and one leader. The presented results verify the effectiveness of the proposed method.

This paper aims is to design an integrated navigation system constituted by low-cost inertial sensors to estimate the orientation of an Autonomous Underwater Vehicle (AUV) during all phases of under water and surface missions. The proposed approach relied on global positioning system, inertial measurement unit (accelerometer & rate gyro), magnetometer and complementary filter technique. Complementary filter operates based on low pass filter and high pass filter to remove noise and bias error of measurement data in the integrated navigation structure, respectively. Consequently, a relatively accurate orientation estimation is provided for guidance/control system. The most important feature of the proposed approach is the ability of switching between GPS and magnetometer sensor consistent with phase-change in the AUV motion. This brings about more accurate estimation of heading angle in both the surface and underwater phase compared to gyro-based navigation. The performance of the proposed algorithm is assessed in a field test executed on a research AUV and in comparison, with Kalman filter.

The main goal of this research is to design a new digital controller for a boost-switching converter in Continuous Conduction Mode (CCM), which operates in Voltage Mode Control (VMC). Boost converter transfer function in the mentioned modes have one Right Half Plane (RHP) zero and a pair of complex poles while their places are severely dependent on input voltage, reference voltage and converter elements. Parameters of the proposed controller have been obtained by using a meta-heuristic multi-objective optimization method to gain an improved converter behavior in startup, load change and reference voltage change conditions along with appropriate gain and phase margins. The proposed controller is a combination of a standard typeIII controller and a PID controller with complex zeros. Simulation and experimental results illustrate that converter performance based on the proposed controller has a significant improvement rather than typeIII controller. Main benefits of the proposed controller includes achieving a suitable response in whole range of converter operation, not to need a current feedback, appropriate stability and simple and cost-effective implementation.

In this paper, we examine the design of a sliding mode control for stochastic systems with data packet losses. It is assumed that there is a network connection in the system's feedback loop and that part of the information may be lost during transmission. The innovation of this paper is to peresent a new method with better  performance In this paper, we first consider an estimated method to compensate for lost data. Then we define an integral sliding surface and design the slider surface controller. Using the Lyapunov method, we will show that this method (with square approximation) will be stable. In the end, numerical examples and simulation results with the help of the content software confirm the sustainability and effectiveness of the proposed method.