-
[show abstract]
[hide abstract]
ABSTRACT: In this paper, a recently developed model governing the cancer growth on a cell population level with combination of immune and chemotherapy is used to develop a reactive (feedback) mixed treatment strategy. The feedback design proposed here is based on nonlinear constrained model predictive control together with an adaptation scheme that enables the effects of unavoidable modeling uncertainties to be compensated. The effectiveness of the proposed strategy is shown under realistic human data showing the advantage of treatment in feedback form as well as the relevance of the adaptation strategy in handling uncertainties and modeling errors. A new treatment strategy defined by an original optimal control problem formulation is also proposed. This new formulation shows particularly interesting possibilities since it may lead to tumor regression under better health indicator profile.
Journal of Theoretical Biology 06/2009; 258(3):444-54. · 2.21 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: In this article, a model-free feedback control design is proposed for the drug administration in mixed cancer therapy. This strategy is very attractive because of the important issue of parameter uncertainties unavoidable when dealing with biological models. The proposed feedback scheme use past measurements to update an on-line simplified model. The control design is then based on model predictive control in which a suitable switching is performed between two different cost functions. The effectiveness of the proposed model-free control strategy is validated using a recently developed model (unknown to the controller) governing the cancer growth on a cells population level under combined immune and chemotherapy and using real human data.
Biotechnology Progress 04/2009; 25(3):690-700. · 2.34 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: This paper presents a reduced mean model of a three-dimensional Eel-like robot. Such a robot is under construction in the context of a national French robotic project. This model is based on mechanical considerations as well as on our experience with an existing 3D continuous model of the target prototype. Identification and validation of the dynamic model are presented here.
Robotics and Biomimetics, 2008. ROBIO 2008. IEEE International Conference on; 03/2009
-
[show abstract]
[hide abstract]
ABSTRACT: In this paper, a multi-variable feedback design for the 3D movement of an eel-like robot is presented. Such a robot is under construction in the context of a national French robotic project. The proposed feedback enables the tracking of a desired 3D position of the eelpsilas head as well as the stabilization of the rolling angle. The control design is based on a recently developed reduced model that have been validated using a 3D complete continuous model described in [3]. Several scenarios are proposed to assess the efficiency of the proposed feedback law.
Intelligent Robots and Systems, 2008. IROS 2008. IEEE/RSJ International Conference on; 10/2008
-
[show abstract]
[hide abstract]
ABSTRACT: In this note, we investigate the problem of remote stabilization via communication networks involving some time-varying delays of known average dynamics. This problem arises when the control law is remotely implemented and leads to the problem of stabilizing an open-loop unstable system with time-varying delay. We use a time-varying horizon predictor to design a stabilizing control law that sets the poles of the closed-loop system. The computation of the horizon of the predictor is investigated and the proposed control law explicitly takes into account an estimation of the average delay dynamics. The resulting closed loop system robustness with respect to some uncertainties on the delay estimation is also considered. Simulation results are finally presented.
IEEE Transactions on Automatic Control 09/2007; · 2.11 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: In this paper, a constrained nonlinear predictive control scheme is proposed for a class of under-actuated nonholonomic systems.
The scheme is based on fast generation of steering trajectories that inherently fulfill the contraints while showing a “translatability” property which is generally needed to derive stability results in receding-horizon schemes. The corresponding open-loop
optimization problem can be solved very efficiently making possible a real-time implementation on fast systems (The resulting
optimization problem is roughly scalar). The whole framework is shown to hold for the well known challenging problem of a
snakeboard constrained stabilization. Illustrative simulations are proposed to assess the efficiency of the proposed solution
under saturation constraints and model uncertainties.
07/2007: pages 1-20;
-
[show abstract]
[hide abstract]
ABSTRACT: This paper relates recent advances in the design of feedback laws for the 3D movement of an Eel-like robot. Such a robot is under construction in the context of a national French robotic project. The proposed feedback enables the tracking of a desired 3D position of the Eel head as well as the stabilization of the rolling angle. A velocity controller is also proposed. The controller is tested on a recently developed complete 3D model in order to assess its efficiency in tackling 3D manoeuvres.
Robotics and Automation, 2007 IEEE International Conference on; 05/2007
-
[show abstract]
[hide abstract]
ABSTRACT: In this paper, a minimum-time oriented state feedback control is proposed for the stabilization of second-ordered chained form system with saturation constraints on the control inputs. The feedback law is based on receding horizon strategy that provides global stabilization of the system for any final desired state. Simulations are given to show the effectiveness of the proposed approach.
Decision and Control, 2005 and 2005 European Control Conference. CDC-ECC '05. 44th IEEE Conference on; 01/2006
-
[show abstract]
[hide abstract]
ABSTRACT: In this paper, voltage stabilization of power systems is considered. The proposed control approach relies on using local feedback strategies to update the OLTC setpoints and a receding horizon global controller to update the reactive power injections and load shedding. The combinatorics associated with the capacitors and load shedding discrete inputs are partially alleviated by using an efficient parametrization and ordering techniques. Simulations are carried out on a benchmark power system to further illustrate the approach.
Decision and Control, 2005 and 2005 European Control Conference. CDC-ECC '05. 44th IEEE Conference on; 01/2006
-
IFAC World Congress; 01/2005
-
[show abstract]
[hide abstract]
ABSTRACT: We investigate the problem of remote stabilization via communication networks. This problem arises when the control law is remotely implemented. The exchange of data between the controller and the system is done via a data communication network described by a deterministic model. This leads to the problem of stabilizing an open-loop unstable system with time-varying delay. Assuming a known general model for the time-delay dynamics, we develop a time-varying horizon predictor, which is used as a basis to build a stabilizing control law that includes explicitly the delay dynamics. This control law is then applied to the case of TCP networks. The experimental results are presented.
Control Applications, 2004. Proceedings of the 2004 IEEE International Conference on; 10/2004
-
[show abstract]
[hide abstract]
ABSTRACT: A discontinuous state-feedback law is proposed for the stabilization of nonholonomic systems in power form. The feedback law is based on receding-horizon strategy in which the open-loop optimization problem is a minimum-time steering one. Sub-optimal formulations are explicitly used to meet real-time implementability requirements. Stability is established in a sampled-data context and illustrative simulations are given to show the effectiveness and the real-time implementability of the proposed scheme.
Decision and Control, 2002, Proceedings of the 41st IEEE Conference on; 01/2003
-
[show abstract]
[hide abstract]
ABSTRACT: A transformation is proposed for single chained form systems. This transformation puts chained form systems in a form close to the Brunovsky linear canonical form and can be utilized to derive an almost stabilizing feedback. This feedback is then extended in order to treat the singularity that arises for some initial conditions in the previous approach. The so obtained feedback is static and discontinuous and globally exponentially stabilizes chained form systems. This feedback law has the advantageous property of being bounded for bounded states and converging to zero along the trajectories of the closed-loop system. This work is straightforwardly extendable to multi-input chained systems.
Decision and Control, 2002, Proceedings of the 41st IEEE Conference on; 01/2003
-
[show abstract]
[hide abstract]
ABSTRACT: Further results are proposed that concern the design and the
convergence of receding-horizon nonlinear observers. The key feature is
the definition of observability radius in relation with a prespecified
compact set of initial configurations. This enables a semiglobal
convergence result to be derived that turns out to be a global
convergence result when appropriate regularity assumptions are made. A
simple example is proposed to illustrate the basic features of the note
IEEE Transactions on Automatic Control 08/2002; · 2.11 Impact Factor
-
International Journal of Control 01/2002; 75(6):421-433. · 0.98 Impact Factor
-
M. Alamir
[show abstract]
[hide abstract]
ABSTRACT: In this paper, a new formulation of constrained stabilizing
receding horizon control is proposed. This formulation is based on the
use of open loop steering path generators. The underlying open loop
optimization problem is scalar in which the decision variable is the
prediction horizon length. Stability is proved in a sampling control
scheme
Decision and Control, 2001. Proceedings of the 40th IEEE Conference on; 02/2001
-
[show abstract]
[hide abstract]
ABSTRACT: A MATLAB based environment is proposed to illustrate the concept
of zero dynamics appearing in nonlinear control design. This is done
through the study of the stability of (torque/flux) oriented control of
an AC-motor. The proposed tool is realized using the MATLAB GUI facility
Decision and Control, 2001. Proceedings of the 40th IEEE Conference on; 02/2001
-
[show abstract]
[hide abstract]
ABSTRACT: In this paper, results are proposed that concern the design and
the convergence of receding-horizon nonlinear observers. The key feature
is the definition of the observability radius in relation to a
pre-specified compact set of initial configurations. This enables a
semi-global convergence result to be derived that turns out to be a
global convergence result when appropriate regularity assumptions are
made. A simple example is proposed to illustrate the basic features of
the observers
Decision and Control, 2001. Proceedings of the 40th IEEE Conference on; 02/2001
-
M. Alamir
[show abstract]
[hide abstract]
ABSTRACT: A robust globally asymptotically stabilizing feedback law is
proposed for the control of rotating stall and surge in axial flow
compressors. This is done in two steps. First, a globally asymptotically
stabilizing parameterized feedback is proposed. Then a numerical design
procedure is developed to compute the feedback parameters in accordance
with some pre-specified robustness criteria. Simulations are proposed to
validate the proposed schemes
Decision and Control, 2000. Proceedings of the 39th IEEE Conference on; 02/2000
-
M. Alamir
[show abstract]
[hide abstract]
ABSTRACT: An algorithm for computing the solutions of nonlinear optimal and robust H<sub>∞</sub> control problems is proposed. The algorithm is based on the use of the collocation method to transform the PDEs into ODEs. Some convergence results are given and several examples are presented
Decision and Control, 2000. Proceedings of the 39th IEEE Conference on; 02/2000
