Miroslav Fikar | Slovak University of Technology (original) (raw)

Papers by Miroslav Fikar

IFAC Proceedings Volumes, 2014

IFAC Proceedings Volumes, 2006

2013 European Control Conference, 2013

We exploit the controllable canonical form of single-input linear parameter-varying (LPV) systems... more We exploit the controllable canonical form of single-input linear parameter-varying (LPV) systems to synthesize explicit Model Predictive Control (MPC) feedback laws. The nonlinear state-parameter dependence is first moved into the feedback term, followed by devising a suitable input constraint set. This allows the MPC problem to be formulated with a quadratic performance index, avoiding costly dynamic programming iterations. The resulting MPC optimization is shown to be convex and can be solved parametrically. The explicit solution takes a form of a piecewise affine (PWA) function which allows to implement the feedback law quickly even with limited computational resources.

2007 European Control Conference, Jul 1, 2007

We consider the problem of reducing the memory footprint of explicit MPC feedback laws for linear... more We consider the problem of reducing the memory footprint of explicit MPC feedback laws for linear systems. A controller defined by a continuous Piecewise Affine (PWA) function is simplified using separation functions. If a state resides in a saturated region, control value is given by the sign of the separator. Thus, instead of storing and evaluating all regions, only the unconstrained regions and the separator are needed. A large case study is provided to evidence that such separators can be constructed efficiently even for very complex explicit MPC solutions.

This report deals with the description of dynamic optimization toolbox (DOTcvp) which is able to ... more This report deals with the description of dynamic optimization toolbox (DOTcvp) which is able to solve constrained optimal control problems (OCP) with the control vector parameterization (CVP) approach. The original continuous problem is transformed into the finite dimensional OCP. Then it is possible to solve the resulting nonlinear programming (NLP) problem with the help of any gradient method with the combination of initial value problem (IVP) solver. For all of this is used SUNDIALS tool which was modified for automatic generation of the necessary gradients in two ways. One of them is a finite difference and the second one, a more accurate method, is the sensitivity equations approach. Several NLP solvers, deterministic and stochastic were implemented in order to ensure higher accuracy not only for small problems. All of this is covered by the MATLAB environment, which offers to us a comfortable control and a pretty graphical output. The toolbox contains an environment for a FORTRAN compiler too, for enabling this option it is needed to have installed a FORTRAN compiler in a MATLAB environment.

49Th Ieee Conference on Decision and Control, 2010

The idea of Explicit Model Predictive Control (MPC) is to find the optimal control input as an ex... more The idea of Explicit Model Predictive Control (MPC) is to find the optimal control input as an explicit Piecewise Affine (PWA) function of the initial conditions. The function, however, is often too complex to be processed by a typical control hardware setup in real time. Therefore the paper proposes a novel method of replacing a generic continuous PWA function by a different function of significantly lower complexity in such a way that optimal closed-loop performance, stability and constraint satisfaction are preserved. The idea is based on eliminating a significant portion of the regions of the PWA function over which the function attains a saturated value. An extensive case study is presented which confirms that a significant reduction of complexity is achieved in general.

Chemical Papers Slovak Academy of Sciences, Mar 31, 2010

This paper presents a case study of model predictive control (MPC) applied to a continuous stirre... more This paper presents a case study of model predictive control (MPC) applied to a continuous stirred tank reactor (CSTR). It is proposed to approximate nonlinear behavior of a plant by several local linear models, enabling a piecewise affine (PWA) description of the model used to predict and optimize future evolution of the reactor behavior. Main advantage of the PWA model

This paper studies a problem of uncertainties in optimal process control of batch processes. We a... more This paper studies a problem of uncertainties in optimal process control of batch processes. We assume that several batches are processed and that run-to-run optimisation can be performed. We propose an integrated two-time scale that optimises between batches to meet terminal constraints and within batches to improve calculated optimal trajectory for model-mismatch. The results obtained from a batch reactor control indicate that the resulting scheme has better convergence properties than individual schemes dealing either with terminal constraints adaptation or with in-batch neighbouring-extremal (NE) control.

2009 European Control Conference, Aug 1, 2009

1997 European Control Conference, Jul 1, 1997

International Journal of Online Engineering, Feb 16, 2012

2015 European Control Conference (ECC), 2015

ABSTRACT The goal of this paper is to present the software tool WebPIDDESIGN for complex manageme... more ABSTRACT The goal of this paper is to present the software tool WebPIDDESIGN for complex management of PID controller design. This tool is suitable for those who need to design the PID controller for the simple closed-loop feedback in an effective and user-friendly way. As the WebPIDDESIGN interface has been currently placed on the Internet, the users may benefit from the simple utilization without the need of complex software and hardware requirements. The features of this tool determine its usability especially for educational purpose. Users of WebPIDDESIGN can reap the benefits of its online form, especially interactivity, information value, ease of use, and accessibility 24/7. This software includes system analysis and identification features, various PID controller design methods, closed loop simulations and evaluation of control quality. As a tool for education, it also provides appropriate theoretical background to specific control design and identification tasks, in such an extent that user is able to understand all performed tasks without an exhaustive effort.

2012 IEEE 51st IEEE Conference on Decision and Control (CDC), 2012

A control input correction strategy is developed whereby an arbitrary given control law may be de... more A control input correction strategy is developed whereby an arbitrary given control law may be deployed when constraint satisfaction, closed-loop stability and safety-critical certification are required. Furthermore the proposed approach allows for notification in case the given control law fails in satisfying basic performance criteria, or when hijacking of communications links or sabotage is suspected. The proposed approach employs a multi-parametric programming approach to least-invasively correct a given controller in a way that is implementable in a manner certifiable for safety-critical deployments.