Loading...
Search for:
external-disturbances
0.006 seconds
Total 48 records
Enhancing the roll dynamics of an AUV by contra-rotating-propellers
, Article Ships and Offshore Structures ; 2020 ; Kamali, A ; Abbaspour, M ; Sharif University of Technology
Taylor and Francis Ltd
2020
Abstract
Roll control of the Autonomous Underwater Vehicles (AUVs) is a significant issue in the current field of research for many researchers in the subject of AUV control system designation. Especially at higher speeds, the roll angle generated by a single rotating propeller or other external disturbances can considerably influence the whole dynamics and therefore the operation of the vehicle. In this paper, the utilisation of a system of contra-rotating-propellers (CRP) to enhance the roll dynamics of an AUV is evaluated by developing a six-degrees-of-freedom (6DOF) dynamics and control systems’ simulator. The results show that: 1. The single propeller system can cause roll angle deflections...
Fault-tolerant predictive trajectory tracking of an air vehicle based on acceleration control
, Article IET Control Theory and Applications ; Volume 14, Issue 5 , 2020 , Pages 750-762 ; Banazadeh, A ; Sharif University of Technology
Institution of Engineering and Technology
2020
Abstract
A novel fault-tolerant model predictive control (MPC)-based trajectory tracking approach for an aerial vehicle is presented in this study. A generalised online sequential extreme learning machine is introduced first to identify the corresponding coefficients of actuator faults. Subsequently, a robust trajectory tracking control is developed based on MPC, where the system constraints can be effectively considered in the designed control scheme. Trajectory tracking control is achieved by controlling only the acceleration of the aerial robot in the MPC structure. This leads to less computational burden and faster closed-loop dynamics. In addition, an effective disturbance observer is employed,...
Adaptive synchronization of uncertain fractional-order chaotic systems using sliding mode control techniques
, Article Proceedings of the Institution of Mechanical Engineers. Part I: Journal of Systems and Control Engineering ; Volume 234, Issue 1 , 2020 , Pages 3-9 ; Siahi Shadbad, A ; Safavi, K ; Salarieh, H ; Sharif University of Technology
SAGE Publications Ltd
2020
Abstract
In this article, an adaptive nonlinear controller is designed to synchronize two uncertain fractional-order chaotic systems using fractional-order sliding mode control. The controller structure and adaptation laws are chosen such that asymptotic stability of the closed-loop control system is guaranteed. The adaptation laws are being calculated from a proper sliding surface using the Lyapunov stability theory. This method guarantees the closed-loop control system robustness against the system uncertainties and external disturbances. Eventually, the presented method is used to synchronize two fractional-order gyro and Duffing systems, and the numerical simulation results demonstrate the...
Adaptive fuzzy nonlinear sliding-mode controller for a car-like robot
, Article 5th IEEE Conference on Knowledge Based Engineering and Innovation, KBEI 2019, 28 February 2019 through 1 March 2019 ; 2019 , Pages 686-691 ; 9781728108728 (ISBN) ; Shojaeefard, M. H ; Amirkhani, A ; Behroozi, H ; Intelligent Systems Scientific Society of Japan; Iran Computer and Video Games Foundation; Islamic World Science Citation Center (ISC) ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
2019
Abstract
In this paper, a nonlinear controller, which can be updated online by means of fuzzy logic, has been proposed for tracking the trajectory of a car-like robot. The advantage of this control scheme is that it eliminates the effects of model disturbances and uncertainties, which cannot be avoided; and especially when we consider the difficult task of determining the exact kinematic and dynamic models of car-like robots. The proposed approach comprises a robust nonlinear section that uses the sliding mode control and a fuzzy section that can update, online, parameters of the nonlinear controller. The stability and the error convergence of the closed-loop system are verified through the Lyapunov...
Simultaneous trajectory tracking and aerial manipulation using a multi-stage model predictive control
, Article Aerospace Science and Technology ; Volume 112 , 2021 ; 12709638 (ISSN) ; Banazadeh, A ; Sharif University of Technology
Elsevier Masson s.r.l
2021
Abstract
With the exception of a few works, the current approaches to aerial manipulation control do not typically consider the system constraints in the control design process. Also, the issue of closed-loop stability in the presence of system constraints is not thoroughly analyzed. In this paper, a novel multi-stage model predictive control (MPC)-based approach for aerial manipulation is proposed to ensure the closed-loop stability in the presence of model uncertainties and external disturbances, while satisfying the operational constraints. The detailed nonlinear model of a general aerial manipulator, consisting of a quadrotor equipped with a 3 degrees of freedom manipulator, is first developed...
Decentralized control of parallel connection of two distributed generation units
, Article 35th Annual Conference of the IEEE Industrial Electronics Society, IECON 2009, Porto, 3 November 2009 through 5 November 2009 ; 2009 , Pages 358-362 ; Karimi, H ; Iravani, R ; Sharif University of Technology
Abstract
This paper presents a decentralized control strategy for the autonomous (islanded) operation of parallel connection of two distributed generation (DG) units. The DG units are electronically interfaced to the host grid at the same point of common coupling (PCC), where the local load is also supplied. In the grid-connected mode, the voltage-sourced converter (VSC) of each DG unit controls the exchange of real and reactive power components with the host grid, based on the conventional dq-current control strategy. In the islanded mode, one of the DG units provides voltage and frequency control for the island, and the other DG unit continues to operate with the pre-islanding dq-current control...
Predictive functional control for active queue management in congested TCP/IP networks
, Article ISA Transactions ; Volume 48, Issue 1 , 2009 , Pages 107-121 ; 00190578 (ISSN) ; Haeri, M ; Sharif University of Technology
2009
Abstract
Predictive functional control (PFC) as a new active queue management (AQM) method in dynamic TCP networks supporting explicit congestion notification (ECN) is proposed. The ability of the controller in handling system delay along with its simplicity and low computational load makes PFC a privileged AQM method in the high speed networks. Besides, considering the disturbance term (which represents model/process mismatches, external disturbances, and existing noise) in the control formulation adds some level of robustness into the PFC-AQM controller. This is an important and desired property in the control of dynamically-varying computer networks. In this paper, the controller is designed based...
A supervisory fuzzy-PID controller for a MIMO biped robot balance in frontal plane
, Article 2008 ASME International Mechanical Engineering Congress and Exposition, IMECE 2008, Boston, MA, 31 October 2008 through 6 November 2008 ; Volume 2 , 2009 , Pages 307-314 ; 9780791848630 (ISBN) ; Haghshenas Jaryani, M ; Farahmand, F ; Sharif University of Technology
2009
Abstract
In this paper we propose to control a bipedal robot in an unstable position by means of a PID controller that gains are turned by a fuzzy logic system. For that, a model of planar 3 linked segment consisting of limb, trunk and extended arms with fixed base is used. Fuzzy if-then rules are constructed based on human expert knowledge and biomechanics studies for tuning of PID's gain. For construction of tuning rules, we have developed an optical measuring system to record experimental data of balance keeping of a human in an unstable position. The control model is based on three sets of different global variables: (1) limb orientation and its derivative, (2) trunk/upper attitude and its...