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observer-controllers
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Robust H∞ hybrid observer-controller design with application to attitude control of 2-DOF helicopter
, Article ASME International Mechanical Engineering Congress and Exposition, Proceedings (IMECE) ; Vol. 4A , 2014 ; ISBN: 9780791846476 ; Merat, K ; Salarieh, H ; Alasty, A ; Meghdari, A ; Sharif University of Technology
Abstract
In this paper, a class of uncertain piecewise affine (PWA) systems, subject to system and measurement external disturbances are studied. The uncertainties are assumed to be norm bounded and the external disturbance signals belong to the L2 space. The problem of optimizing the system response in the H?sense, by means of a piecewise affine observer-controller, is formulated as an optimization problem subject to a number of constraints in the form of matrix inequalities. The derived constraints are obtained by considering a partially piecewise quadratic Lyapunov function in combination with the general conditions for H?stability. Then the uncertain PWA approximation of the nonlinear attitude...
Observer based feedback control of a biodynamical model of tumor growth with sampled measurements
, Article 2016 European Control Conference, ECC 2016, 29 June 2016 through 1 July 2016 ; 2017 , Pages 2423-2428 ; 9781509025916 (ISBN) ; Salarieh, H ; Alasty, A ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
2017
Abstract
This paper deals with the cancer treatment scheduling via observer-based feedback control of a tumor growth biodynamical model. An experimental nonlinear model is utilized to design a feedback controller. This model was validated by a pharmacological study on xenograft models obtained by transplantation of colon carcinoma cell lines in athymic mice. Input-output feedback linearization approach is used to linearize the nonlinear model of the system and design a control law. It is assumed that tumor weight can be measured in definite intervals. So a continuous-discrete observer is designed to estimate states of the system based on discrete sampled data which are tumor weight in this case. To...
Designing Hybrid Controller, Impleimentation on Experiment Model and Proving Stability for 3-Pole AMB
, M.Sc. Thesis Sharif University of Technology ; Salarieh, Hassan (Supervisor) ; Alasti, Aria (Supervisor)
Abstract
The design and implementation of the hybrid control method for a three-pole active magnetic bearing (AMB) is proposed in this paper. The system is inherently nonlinear and conventional nonlinear controllers are a little complicated while the proposed hybrid controller has a piecewise linear form, i.e., linear in each sub-region. A state-feedback hybrid controller is designed in this study and the unmeasurable states are estimated by an observer. The gains of the hybrid controller are obtained by the LQR method in each sub-region. To evaluate the performance, the designed controller is implemented on an experimental setup. The experimental results show that the proposed method can efficiently...
Hybrid Control of an Unmanned Helicopter System Maneuver
, M.Sc. Thesis Sharif University of Technology ; Salarieh, Hassan (Supervisor)
Abstract
As a subset of hybrid systems, piecewise affine (PWA) systems are capable of approximating the behavior of a wide range of nonlinear systems. Considering the preliminaries regarding these systems and the vast literature gathered around them, the main contributions of the current study are presented in two separate sections. In the first section a class of uncertain piecewise affine systems subject to additive noise are studied. The problem of minimizing the bound on the variance of the steady response of these systems, by means of a piecewise affine observer-controller, is formulated as an optimization problem subject to a number of constraints in the form of matrix inequalities. Then the...
Observer based minimum variance control of uncertain piecewise affine systems subject to additive noise
, Article Nonlinear Analysis: Hybrid Systems ; Volume 19 , 2016 , Pages 153-167 ; 1751570X (ISSN) ; Merat, K ; Salarieh, H ; Alasty, A ; Meghdari, A ; Sharif University of Technology
Elsevier Ltd
Abstract
In this paper, a class of uncertain piecewise affine (PWA) systems, subject to system and measurement additive noises is studied. The additive noise signals considered here do not vanish at the equilibrium and the uncertainties are norm bounded. The problem of minimizing the bound on the variance of the steady response of uncertain PWA systems, by means of a hybrid observer-controller, is formulated as an optimization problem subject to a number of constraints in the form of matrix inequalities. The derived constraints are obtained by considering a piecewise quadratic Lyapunov function in combination with the general stability conditions regarding the existence of an upper stochastic bound...
Adjacent segments biomechanics following lumbar fusion surgery: a musculoskeletal finite element model study
, Article European Spine Journal ; Volume 31, Issue 7 , 2022 , Pages 1630-1639 ; 09406719 (ISSN) ; Arjmand, N ; Shirazi-Adl, A ; Sharif University of Technology
Springer Science and Business Media Deutschland GmbH
2022
Abstract
Purpose: This study exploits a novel musculoskeletal finite element (MS-FE) spine model to evaluate the post-fusion (L4–L5) alterations in adjacent segment kinetics. Methods: Unlike the existing MS models with idealized representation of spinal joints, this model predicts stress/strain distributions in all passive tissues while organically coupled to a MS model. This generic (in terms of musculature and material properties) model uses population-based in vivo vertebral sagittal rotations, gravity loads, and an optimization algorithm to calculate muscle forces. Simulations represent individuals with an intact L4–L5, a preoperative severely degenerated L4–L5 (by reducing the disc height by ~...
Pole assignment and distributed output feedback control via graph-based decomposition
, Article International Journal of Control ; 2022 ; 00207179 (ISSN) ; Babazadeh, M ; Sharif University of Technology
Taylor and Francis Ltd
2022
Abstract
A new distributed observer-based output feedback control design with an arbitrary control structure is proposed. Assuming that the linear time-invariant (LTI) system does not have any fixed-modes with respect to the control structure, the pole placement at the desired locations becomes theoretically feasible. In this paper, the structural output feedback controller design is transformed into equivalent problems based on a graph-theoretic approach. Two augmented structures are established and formulated as the solution of a set of binary linear programs (BLP). The first one facilitates the incorporation of the maximum number of edges in the principal bipartite graph and the second one results...