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exponential-stabilization
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Dynamic feedback stabilization of timoshenko beam with internal input delays
, Article WSEAS Transactions on Mathematics ; Volume 17 , 2018 , Pages 101-112 ; 11092769 (ISSN) ; Jalili Rahmati, A ; Badpar, F ; Sharif University of Technology
World Scientific and Engineering Academy and Society
2018
Abstract
In this paper, we consider the exponential stabilization problem of a Timoshenko beam with interior local controls with input delays. In the past, most of the stabilization results for the Timoshenko beam were on the boundary control with input delays. In the present paper we shall extend the method treating the boundary control with delays to the case of interior local control with delays. Essentially we design a new dynamic feedback control laws that stabilizes exponentially the system. Detail of the design procedure of the dynamic feedback controller and analysis of the exponential stability are given. © 2018 World Scientific and Engineering Academy and Society. All Rights Reserved
Boundary Control of Vibration in Satellite Flexible Solar Panels
, M.Sc. Thesis Sharif University of Technology ; Alasty, Aria (Supervisor) ; Salarieh, Hassan (Supervisor) ; Vatankhah, Ramin (Co-Advisor)
Abstract
Many spacecrafts and satellites have long flexible components, the most common ones are the satellites with flexible solar panels, which are used to provide the satellite energy. The governing equations of the satellite rigid motion along with the solar panels vibrations are the combination of the coupled partial and ordinary differential equations. Various reasons, such as the satellite maneuvers and the external disturbances, cause the vibration of panels. Due to the dependence between the governing equations of the satellite rigid motion and the flexible components vibrations, these vibrations affect the satellite rigid dynamics and the control aims; therefore, in addition to the...
Vibration Control of Nonclassical Microbeams Using Boundary Control Theory of Partial Differential Equations
, Ph.D. Dissertation Sharif University of Technology ; Alasty, Aria (Supervisor)
Abstract
Nowadays, continuous systems such as strings, bars, beams and plates have become widespread in science and engineering applications. To achieve the control purposes of continuous systems, most of engineers use discretization techniques to reduce the governing partial differential equation (PDE) into a set of ordinary differential equations (ODEs). From practical point of view, this model reduction can cause many problems such as in-domain measurement and actuation and control spillover. This thesis attempts to investigate the problem of vibration control of nonclassical microscale beams using the partial differential equation control theory which eliminates spillover instabilities. To this...
A modification on performance of MEMS gyroscopes by parametro-harmonic excitation
, Article ASME 2010 10th Biennial Conference on Engineering Systems Design and Analysis, ESDA2010, 12 July 2010 through 14 July 2010 ; Volume 5 , 2010 , Pages 433-441 ; 9780791849194 (ISBN) ; Salarieh, H ; Vossoughi, G ; Alasty, A ; Sharif University of Technology
Abstract
In this paper, parametric excitation for MEMS gyroscope proposed by Oropeza-Ramos, et al. [1-4] is examined and problems associated with this kind of excitation are shown. It is proved that origin has exponential stability for some sets of parameter values (including those considered in [1-4]). This stability is shown to be global for linearized system and local for the general nonlinear system. Hence, it is concluded that if there would be a periodic orbit, the system has difficulties reaching it. As a solution, a harmonic term to the parametric excitation is added and the new actuation is referred to as parametro-harmonic excitation. It is shown that there are some parameter values for...
Design of Continuous and Time-Invariant Controllers for Exponential Stabilization of Periodic Walking and Running Locomotion in Planar Bipedal Robots
, Ph.D. Dissertation Sharif University of Technology ; Sadati, Nasser (Supervisor)
Abstract
During the last decades there have been enormous advances in robot control of dynamic walking and running. The desire to study legged locomotion has been motivated by 1) the desire to replace humans in hazardous occupations, 2) the desire to assist disabled people to walk and 3) the desire to investigate the complicated motions of the mankind. The control of dynamic walking and running is complicated by (i) limb coordination, (ii) hybrid nature of running due to presence of impact and takeoff, (iii) underactuation and overactuation, (iv) inability to apply the Zero Moment Point (ZMP) criterion, (v) lack of algorithms to achieve feasible period-one orbits, and (vi) conservation of angular...
On the stability issues for fuzzy large-scale systems
, Article Fuzzy Sets and Systems ; Volume 174, Issue 1 , July , 2011 , Pages 31-49 ; 01650114 (ISSN) ; Sadati, N ; Zarif, M. H ; Sharif University of Technology
2011
Abstract
The main objective of this paper is to investigate the stability and stabilization problem of fuzzy large-scale systems in which the system is composed of a number of Takagi-Sugeno fuzzy subsystems with interconnection. Instead of fuzzy parallel distributed compensation (PDC) design, nonlinear state feedback controllers are used in stabilization of the overall large-scale system. Based on Lyapunov stability theory, linear matrix inequalities (LMIs) conditions are derived for asymptotic and exponential stability. Two numerical examples are given to confirm the analytical results and illustrate the effectiveness of the proposed strategy
Continuous-time update laws with radial basis step length for control of bipedal locomotion
, Article Electronics Letters ; Volume 46, Issue 21 , 2010 , Pages 1431-1433 ; 00135194 (ISSN) ; Sadati, N ; Gruver, W. A ; Dumont, G. A ; Sharif University of Technology
2010
Abstract
Presented is a novel approach for designing continuous-time update laws to update the parameters of stabilising controllers during continuous phases of bipedal walking such that (i) a general cost function, such as the energy of the control input over single support, can be minimised in an online manner, and (ii) the exponential stability of the corresponding limit cycle for the closed-loop impulsive system is not affected. Formally, a class of update laws with a radial basis step length is developed to minimise a cost function in terms of the stabilising controller parameters and initial states of the mechanical system
Boundary control of anti-symmetric vibration of satellite with flexible appendages in planar motion with exponential stability
, Article Acta Astronautica ; Volume 147 , 2018 , Pages 219-230 ; 00945765 (ISSN) ; Salarieh, H ; Alasty, A ; Vatankhah, R ; Sharif University of Technology
Elsevier Ltd
2018
Abstract
In this research, we have investigated the planar maneuver of a flexible satellite with appendages anti-symmetric vibration. The hybrid governing equations are comprised of coupled partial and ordinary differential equations which are derived by employing Hamilton's principle. In this paper, control goals are the tracking desired pitch angle along with the flexible appendages vibration suppression simultaneously by using only one control torque which is applied to the central hub. The boundary control is proposed to fulfill these control aims; furthermore, this boundary control ensures that spillover instability phenomenon is eliminated, and in-domain sensors and actuators implement are...
Exponential stabilization of flexural sway vibration of gantry crane via boundary control method
, Article JVC/Journal of Vibration and Control ; Volume 26, Issue 1-2 , 2020 , Pages 36-55 ; Najafi Ardekany, A ; Alasty, A ; Sharif University of Technology
SAGE Publications Inc
2020
Abstract
This paper aims to develop a boundary control solution for complicated gantry crane coupled motions. In addition to the large angle sway motion, the crane cable has a flexural transverse vibration. The Hamilton principle has been utilized to derive the governing partial differential equations of motion. The control objectives which are sought include: moving the payload to the desired position; reducing the payload swing with large sway angle; and finally suppressing the cable transverse vibrations in the presence of boundary disturbances simultaneously. These simultaneous boundary control objectives make the problem challenging. The proposed control approach is based on the original...