The benefits of parametric programming for the design of optimal controllers for constrained systems are widely acknowledged, especially for the case of linear systems. In this work we attempt to exploit these benefit...
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ISBN:
(纸本)9783540726982
The benefits of parametric programming for the design of optimal controllers for constrained systems are widely acknowledged, especially for the case of linear systems. In this work we attempt to exploit these benefits and further extend the theoretical contributions to multi-parametric modelpredictivecontrol (mp-MPC) for non-linear systems with state and input constraints. The aim is to provide an insight and understanding of multi-parametric control and its benefits for non-linear systems and outline key issues for ongoing research work.
In this paper, a new contractive receding horizon scheme is proposed for the stabilization of constrained nonlinear systems. The proposed formulation uses a free finite prediction horizon without explicit use of a con...
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ISBN:
(纸本)9783540726982
In this paper, a new contractive receding horizon scheme is proposed for the stabilization of constrained nonlinear systems. The proposed formulation uses a free finite prediction horizon without explicit use of a contraction stability constraint. Another appealing feature is the fact that the resulting receding horizon control is in pure feedback form unlike existing contractive schemes where open-loop phases or a memorized threshold are used to ensure the contraction property in closed loop. The control scheme is validating on the swing-up and stabilization problem of a simple and a double inverted pendulums.
It has recently been shown that the feedback solution to linear and quadratic constrained modelpredictivecontrol (MPC) problems has an explicit representation as a piecewise linear (PWL) state feedback. For nonlinea...
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ISBN:
(纸本)9783540726982
It has recently been shown that the feedback solution to linear and quadratic constrained modelpredictivecontrol (MPC) problems has an explicit representation as a piecewise linear (PWL) state feedback. For nonlinear MPC the prospects of explicit solutions are even higher than for linear MPC, since the benefits of computational efficiency and verifiability are even more important. Preliminary studies on approximate explicit PWL solutions of convex nonlinear MPC problems, based on multi-parametric nonlinear Programming (mp-NLP) ideas show that sub-optimal PWL controllers of practical complexity can indeed be computed off-line. However, for non-convex problems there is a need to investigate practical computational methods that not necessarily lead to guaranteed properties, but when combined with verification and analysis methods will give a practical tool for development and implementation of explicit NMPC. The present paper focuses on the development of such methods. As a case study, the application of the developed approaches to compressor surge control is considered.
This paper addresses the disturbance attenuation problem in nonlinear moving horizon control. Conceptually a minimax formulation with a general dissipation constraint is suggested and theoretical results on closed-loo...
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ISBN:
(纸本)9783540726982
This paper addresses the disturbance attenuation problem in nonlinear moving horizon control. Conceptually a minimax formulation with a general dissipation constraint is suggested and theoretical results on closed-loop dissipation, L2 disturbance attenuation and stability are discussed. The implementation issue is attacked with respect to tracking a reference trajectory in the presence of external disturbances and control constraints, and a computationally tractable algorithm is given in the framework of LMI optimization. Simulation and comparisons of setpoint tracking control of a CSTR are presented.
In this paper, an alternative approach to the computation of control invariant sets for piecewise affine systems is presented. Based on two approximation operators, two algorithms that provide outer and inner approxim...
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ISBN:
(纸本)9783540726982
In this paper, an alternative approach to the computation of control invariant sets for piecewise affine systems is presented. Based on two approximation operators, two algorithms that provide outer and inner approximations of the maximal robust control invariant set are presented. These algorithms can be used to obtain a robust control invariant set for the system. An illustrative example is presented.
In this paper we present a nonlinearpredictivecontrol strategy for the supervision of networked control systems subject to coordination constraints. Such a system paradigm, referred hereafter to as constrained dynam...
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ISBN:
(纸本)9783540726982
In this paper we present a nonlinearpredictivecontrol strategy for the supervision of networked control systems subject to coordination constraints. Such a system paradigm, referred hereafter to as constrained dynamic network, is characterized by a set of spatially distributed dynamic systems, connected via communication channels, with possible dynamical coupling and constraints amongst them which need to be controlled and coordinated in order to accomplish their overall objective. The significance of the method is that it is capable of ensuring no constraints violation and loss of stability regardless of any, possibly unbounded, time-delay occurrence. An application to the coordination of. two autonomous vehicles under input-saturation and formation accuracy constraints is presented.
A novel robust controller, chance constrained nonlinear MPC, is presented. Time-dependent uncertain variables are considered and described with piecewise stochastic variables over the prediction horizon. Restrictions ...
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ISBN:
(纸本)9783540726982
A novel robust controller, chance constrained nonlinear MPC, is presented. Time-dependent uncertain variables are considered and described with piecewise stochastic variables over the prediction horizon. Restrictions are satisfied with a user-defined probability level. To compute the probability and its derivatives of satisfying process restrictions, the inverse mapping approach is extended to dynamic chance constrained optimization cases. A step of probability maximization is used to address the feasibility problem. A mixing process with both an uncertain inflow rate and an uncertain feed concentration is investigated to demonstrate the effectiveness of the proposed control strategy.
This paper investigates vision based robot control based on a receding horizon control strategy. The stability of the receding horizon control scheme is guaranteed by using the terminal cost derived from an energy fun...
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ISBN:
(纸本)9783540726982
This paper investigates vision based robot control based on a receding horizon control strategy. The stability of the receding horizon control scheme is guaranteed by using the terminal cost derived from an energy function of the visual feedback system. By applying the proposed control scheme to a two-link direct drive manipulator with a CCD camera, it is shown that the stabilizing receding horizon control nicely works for a planar visual feedback system. Furthermore, actual nonlinear experimental results are assessed with respect to the stability and the performance.
A multi-stage nonlinearmodelpredictivecontroller is derived for the real-time coordination of multiple aircraft. In order to couple the versatility of hybrid systems theory with the power of NMPC, a finite state ma...
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ISBN:
(纸本)9783540726982
A multi-stage nonlinearmodelpredictivecontroller is derived for the real-time coordination of multiple aircraft. In order to couple the versatility of hybrid systems theory with the power of NMPC, a finite state machine is coupled to a real time optimal control formulation. This methodology aims to integrate real-time optimal control with higher level logic rules, in order to assist mission design for flight operations like collision avoidance, conflict resolution, and reacting to changes in the environment. Specifically, the controller is able to consider new information as it becomes available. Stability properties for nonlinearmodelpredictivecontrol are described briefly along the lines of a dual-mode controller. Finally, a small case study is presented that considers the coordination of two aircraft, where the aircraft are able to avoid obstacles and each other, reach their targets and minimize a cost function over time.
The paper reports on recent progress in the real-time computation of constrained closed-loop optimal control, in particular the special case of nonlinearmodelpredictivecontrol, of large differential algebraic equat...
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ISBN:
(纸本)9783540726982
The paper reports on recent progress in the real-time computation of constrained closed-loop optimal control, in particular the special case of nonlinearmodelpredictivecontrol, of large differential algebraic equations (DAE) systems arising e.g. from a MoL discretization of instationary PDE. Through a combination of a direct multiple shooting approach and an initial value embedding, a so-called "real-time iteration" approach has been developed in the last few years. One of the basic features is that in each iteration of the optimization process, new process data are being used. Through precomputation - as far as possible - of Hessian, gradients and QP factorizations the response time to perturbations of states and system parameters is minimized. We present and discuss new real-time algorithms for fast feasibility and optimality improvement that do not need to evaluate Jacobians online.
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