In this paper, a FIWARE based control implementation framework for supervisory control of inputoutput models, in Discrete Event System (DES) form, will be introduced, through the case study of an industrial product transfer system having a parametric number of conveyor belts. Each conveyor belt has an actuator (motor) for the belt's clockwise move and a sensor for the detection of the presence of a product. The model of each actuator and the model of each sensor of the belt are expressed in DES form. The input-output relation between consecutive conveyor belts is formally expressed. The satisfactory cooperation between consecutive conveyor belts has been guaranteed by developing a set of two types of supervisors for each cooperative pair. The actuators and the sensors of each belt have been described as smart data models. Finally, an implementation of the proposed supervisor scheme in FIWARE has been proposed.

This study explores the challenges of achieving triangular decoupling in a specific group of linear parameter-dependent systems that have uncertain structures, with a particular emphasis on its relevance to four-wheel steering (4WS) vehicles. A new method is presented, combining a state feedback controller that includes static and time-varying elements. The main goal of this controller design is to guarantee triangular decoupling properties and Hurwitz invariability in the face of system uncertainties. The proposed method involves developing the controller and setting solvability criteria to transform the original Parameter Dependent Uncertain System into an uncertain Linear Time-Invariant (LTI) system and subsequently meeting LTI triangular decoupling characteristics. The practical significance of the results is shown by their effective use in controlling the motion of a velocity varying four-wheel steering (4WS) car model with uncertain virtual mass and cornering stiffnesses.

A supervisory control architecture is developed for the discrete event model of a manufacturing educational testbed of a car assembly line in the presence of faults. The task of the plant is the assembly of the chassis and the roof of a car. The backbone of the assembly line is a transporter that makes the link of all sections of the plant. The goal of the paper is the coordination of the line. To accomplish this goal, the model of the plant in the presence of faults is derived, appropriate regular languages describing the desired performance of the plant are developed and finally appropriate supervisors, satisfying the design requirements, are determined in modular form. To satisfy the class of design requirement considered here, general criteria for the physical realizability of a supervisor, with respect to any process, are established.

To improve the manoeuvrability of differential drive mobile robots around a straight path on a horizontal plane, an I/O decoupling control scheme is proposed through a proportional controller that uses real time measurements of the kinetic variables of the mobile robot and measurements of the orientation of the robot, received through a wireless network providing communication delays. The present control scheme is based on the linear approximant of the robot model. The I/O decoupling design requirement is proven to be always satisfied and the controller is proven to be a common controller for various values of the robot parameters The stability and asymptotic command following of the closed loop system is studied. The resemblance of the performance of the closed loop system, using the delayed controller, to the respective response of the closed loop system for zero delay, is accomplished through a metaheuristic algorithm. The efficiency of the derived controller when applied to the nonlinear model of the mobile robot is illustrated through simulations.

The problem of controlling the position of a magnetically levitated ball is studied through a PD state feedback linear controller and the simultaneous satisfaction of a set of individual miscellaneous design requirements including stability, command following, model following and appropriately bounded input. The requirements are defined over the linear approximant of the magnetic levitation system. Also, for the solution of the problem, a metaheuristic algorithm, based on the linear approximant of the magnetic levitation system, is proposed. The performance of the proposed control scheme, for the resulting nonlinear closed loop system, is illustrated through a series of computational experiments.

The problem of active vibration absorption for ride comfort improvement is investigated upon a quarter car model. Using the linear approximant of the plant, a PID controller that minimizes the L1 norm of the impulse response mapping the disturbance to the performance output is proposed. The controller parameters are selected using a metaheuristic algorithm. The performance of the proposed scheme is illustrated through simulation.

The problem of speed control of a permanent magnet synchronous motor is investigated in the presence of time delays due to wireless signal transmission among the controller, the sensors and the actuators. In the present paper, the decoupling controller approach proposed in [1] is extended to compensate the presence of the delays and to achieve satisfactory performance despite their presence. In particular, the research focuses mainly on the stability of the time delay closed loop system.

The general class of linear singular neutral multi delay systems is introduced. The controller is of the general proportional multi delay measurement output feedback type. For the case of regularizable linear singular multi delay systems the design problem of Exact Model Matching (EMM) is solved under the assumption that the ideal model is left invertible. The necessary and sufficient conditions for the problem to admit a realizable controller solution are established and the general solution of the realizable controllers is derived.

The problem of triangular decoupling with simultaneous disturbance rejection (TDDR) is studied for general neutral multi delay systems via a realizable dynamic multi delay controller feeding back measurable disturbances and the plant measurement outputs. The necessary and sufficient conditions for the problem to have a solution are established and the general analytical expression of the realizable multi delay dynamic controllers solving the problem is derived. The results are successfully applied to control an activated sludge process with varying dissolved oxygen concentration at the influent.

A robust control scheme for an electro hydraulic actuator is presented. A PID (Proportional - Integral - Derivative) controller is designed for controlling the position of the actuator in a wide range of physical uncertainties and external disturbances. The performance of the actuator variables is illustrated via simulations. In the future the present results will be applied to a real experimental system involving a double acting cylinder (Festo - model), with an electro hydraulic servo valve or an ON - OFF hydraulic valve where the PID controller will be realized in MATLAB environment with a Q4 Quanser card.

The problem of fault detection is investigated for the case of Sequential Interindustry Models (SIMs). The model is in discrete time descriptor form including non measurable total outputs and uncertain final demand orders. For this model category the problem of fault detection is studied on the basis of the design of two observers.

Time delay system descriptions are usually met in mechanical systems and industrial processes. Here, the general class of linear singular neutral multi delay systems is introduced. The controller is of the general proportional multi delay state feedback type. For the case of regularizable linear singular neutral multi delay systems the design problem of disturbance decoupling (DD) is solved under the constraint that the closed loop system must be left invertible. The necessary and sufficient conditions for the problem to admit a realizable solution are established and the general solution of the realizable controllers is derived.

In this paper a robust tracking controller is designed for a hydraulic actuator controlled by a variable displacement vane pump. The nonlinear model of the actuator is linearized around equilibrium points and a robust tracking controller is designed for the linear model covering step and ramp reference and disturbance signals. The proposed robust controller is applied to the nonlinear model. The robust stability of the closed loop linear model and the local stability of the nonlinear model are guaranteed under sufficient conditions. The robust controller is derived using a finite step algorithm based on a Hurwitz invariability technique. Simulation results for various uncertain model parameters are presented indicating the satisfactory performance of the robust controller for the nonlinear model of the hydraulic actuator.

In this paper the problem of fault detection is investigated for the case of a time varying input-output Leontief model with non measurable total outputs and uncertain net product vector. The capital coefficient matrix is considered to be block diagonal and singular. For this model category the problem of fault detection is solved on the basis of the design an appropriate unknown input observer.

The problem of block decoupling is studied for the case of general neutral multi delay systems. The system is not restricted to be square and invertible. The controller is of the general neutral dynamic type involving a dynamic feedback and dynamic precompensator. Two different cases of feedback are studied. The first is the case of measurable output feedback and second is the case of performance output feedback. The controller is restricted to be realizable. The necessary and sufficient conditions for the problem to be solvable are established. The general class of the realizable controllers solving the problem is derived. The closed loop transfer function is proven to have arbitrary characteristic polynomial thus facilitating command tracking and stability.

A multi flight condition aircraft control autopilot system is proposed to control the horizontal flight of an aircraft involving atmospheric gusts. The control system involves a robust PID controller that stabilizes the closed loop system for various flight conditions. Considering the stability derivatives of the aircraft and the velocity of the aircraft to be uncertain parameters the robust stabilizing and disturbance attenuation controller is designed to cover full envelop pitch control. The robust PID controller parameters are computed using a finite step algorithm based on a Hurwitz invariability technique. Solvability conditions are derived. Simulation results for four different flight conditions are presented indicating the satisfactory performance of the robust controller in the presence of atmospheric gusts.

For the class of non square general neutral time delay systems the problem of triangular decoupling is extensively solved using a dynamic realizable controller with dynamic measurement output feedback and dynamic precompensator. The necessary and sufficient condition for the solvability of the problem is established and a general class of realizable controller matrices solving the problem is derived. The condition is proven to be the right invertibility of the open loop system. The above results are successfully applied to a small scale activated sludge process (ASP) where a two stage dynamic controller is designed. The inner loop controller is a triangular decoupling controller while the outer loop controller, is used to compensate model uncertainties and nonlinearities of the plant. The performance of the closed loop system is illustrated through simulation.

The control problem of a central heating system is studied via a PD controller feeding back the environment temperature and the performance output, i.e. the temperature of the heated room. The design goal is to compensate the influence of the environment temperature to the room temperature. To achieve this goal, a PI controller has supplementary been used. Even though, the controller is simple and easily implementable to low level control architectures, the performance the closed loop system is satisfactory. The parameters of the controller are computed using pure and mixed heuristic schemes based on the linearization of the nonlinear general neutral plant and minimizing the norm of the influence of the disturbance to the plant output.

The problem of robust pole placement in a specific disk is solved for uncertain polynomials having uncertain degree. This particular problem is used for enhancing the results of many robust control problems based on Hurwitz invariability such as robust stabilizability of uncertain systems via static state feedback, robust asymptotic command tracking, robust PID design, etc.. The present results are successfully applied to control the pressure of a variable displacement hydraulic pump having uncertain leakage flow coefficient through asymptotic command tracking.

Simple algebraic criteria are derived for the solvability of the combined problem of Triangular Decoupling and Disturbance Rejection (TDDR) for general neutral multi-delay systems with measurable and non-measurable disturbances, via proportional measurable disturbance feedback and measurement output feedback. Additionally, the necessary and sufficient conditions, for the problem to admit a realizable solution, are established and the general analytical expression of the realizable controller matrices solving the problem are determined.

The application of multivariable step-wise safe switching controllers (MSWSS) for climate control of a greenhouse is presented. The system of the greenhouse is described by a simplified model, incorporating heating and natural ventilation. The advantages of applying MSWSS on the greenhouse are presented and the performance of the algorithm is illustrated through simulation results. The application of MSWSS controllers improves significantly the greenhousepsilas performance with respect to settling time and disturbance attenuation, considering as performance variable the inside air temperature of the greenhouse.

The performance of Multivariable Step-Wise Safe Switching Iterative Feedback Tuning is studied for a constant turning force system under varying cutting conditions. The tuning technique does not use a plantpsilas model, neither nonlinear or approximate linearized, and is based on specific experiments performed on the closed-loop plant. Controller parameter tuning aims to achieve minimization of a quadratic performance criterion, that limits cutting force deviations from a desired value, as cutting depth varies with time. A state feedback PI controller is combined with a state observer estimating the acceleration of the servomechanism feeding the cutting machine. The proposed tuning algorithm is shown through simulation results to improve the performance of ldquocommonrdquo controllers initially tuned through a metaheuristic search algorithm.

Simple algebraic criteria are derived for the solvability of the combined problem of I/O Decoupling and Disturbance Rejection (DDR) for general neutral multi-delay systems with measurable and nonmeasurable disturbances, via proportional measurable disturbance feedback and measurement output feedback. Additionally, the necessary and sufficient conditions, for the problem to admit a realizable solution, are established and the general analytical expression of the realizable controller matrices solving the problem are determined.

A heuristic control design scheme is proposed for multivariable nonlinear processes. The control design problem is considered to be formulated as an optimization under constraints problem. Actuator, state and/or output variable constraints may be considered. The proposed heuristic control design scheme is based on a metaheuristic search algorithm, that utilizes process simulation blocks in a black-box approach. At each iteration of the algorithm new candidate controllers are randomly selected within the controller parameter space. The location and the range of the search area changes adaptively during the iterations of the algorithm.

Iterative Feedback Tuning (IFT) Safe Switching Algorithm is extended for the case of multivariable nonlinear systems with unknown descriptions. The proposed scheme incorporates multivariable IFT techniques, with a multivariable step-wise safe switching algorithm. Using the IFT algorithm for tuning safe switching controllers eliminates the need for identifying the MIMO linear models that describe the plant around trim (operating) points. Instead of that, specific experiments proposed by multivariable IFT are performed, in order to tune the parameters of "common" MIMO controllers for adjacent trim points. Controller tuning is based on optimizing a cost criterion appropriately defined to express the desired closed loop performance characteristics simultaneously for adjacent operating areas.

The problem of controlling the suspension deflection of a quarter-car active suspension system using a robust tracking controller is proposed. The proposed robust asymptotic tracking and disturbance attenuation controller aims to keep the suspension deflection asymptotically to zero despite road disturbances and physical system uncertainties. The robust controller design technique is based on the respective results of Hurwitz invariability. The robust controller parameters are computed using an analytic algorithm. The effectiveness of the proposed controller is illustrated to an uncertain and disturbed environment.

The problem of controlling the lateral position of tractor- trailer vehicle is studied. A robust asymptotic tracking and disturbance attenuation controller is proposed. The goal of the controller is to keep the vehicle centered to a desired lane despite physical uncertainties and velocity variations. The robust controller parameters are computed using an analytic algorithm. The effectiveness of the results is illustrated through simulation.

A control design scheme is proposed for sloshing suppression during liquid transfer using robotic manipulators. The container of the liquid is transferred by an articulated manipulator. The motion of the liquid is approximated using the well-known pendulum-type model. The proposed control scheme combines a partial inverse dynamics controller with a PID controller tuned with a "metaheuristic" search algorithm. The proposed controller exploits measurements of the manipulator and the container position and velocity variables, but does not require measurements of the pendulum's position and velocity. The proposed design technique succeeds to sufficiently suppress liquid sloshing within the container, while dealing with practical problems like the lack of measurements of the liquid's motion within the tank.

The application of a metaheuristic search algorithm is proposed to determine the degrees of freedom of a linear state feedback control law, designed to achieve independent force and position control of multitask cooperating robotic manipulators. The determination of the appropriate values for the controller's degrees of freedom may be formulated as an optimization under constraints problem. The metaheuristic search algorithm provides an easy to implement and computationally efficient solution for this problem, which is complicated due to the large number of constraints, in addition to the highly nonlinear structure of the functions that determine the " squeezing forces".

In a previous paper we introduced a supervisory control framework for setting the operating point of an industrial process with unknown characteristics. Here we extend this methodology for the case of MIMO processes. The proposed supervisory control framework is agent-based and it involves modeling agents and intelligent agents. The modeling agents derive local steady-state models of the process during normal process operation by using various identification techniques, each of which corresponds to a different instantiation of our system. The intelligent agents are proposed to be implemented using finite automata units. The performance of the proposed scheme is illustrated through simulation results on well-known benchmark problems of chemical industry.

The problem of disturbance rejection (DR) for general linear left-invertible neutral multi-delay systems, via proportional realizable controller feeding back measurable disturbances and measurement outputs, is studied here. The necessary and sufficient conditions for the problem to have a realizable solution are established and the general analytical expressions of the controller matrices solving the problem are derived. The conditions and the solution of the controller are computed using a finite number of explicit algebraic manipulations.

Finite precision dynamic output feedback controllers are proposed for robust pole assignment of SISO linear systems with nonlinear uncertain structure. The realizability of the controller is guaranteed by designing an independent from the uncertainties controller. Necessary and sufficient conditions for the problem to have a solution, as well as the general solution for the controller parameters are derived.

The present work contributes towards the development of a scheme for control of squeezing forces, which are exerted by cooperating manipulators on a carried load subject to holonomic constraints. The forces space is decomposed into moving forces, which cause the load's motion, and controllable forces, which can be controlled independently from the load's position. A way of modeling the controllable forces is introduced, such that the controllable forces are directly related to the squeezing forces applied on the load. The proposed technique contributes towards more efficient control of squeezing forces.

A generic heuristic algorithm is introduced for the derivation of "common" PI controllers that is PI controllers that achieve specific performance requirements simultaneously for all members of a set of linear models, called the target set. Common PI controllers find application for the control of processes with multi-linear description, since they can achieve safe and satisfactory performance for all switching events between the linear models of the target set. The heuristic algorithm is generic, simple to use and can be extended for other classes of controllers. The performance of the heuristic algorithm is illustrated for the case of a double effect evaporator process

The problem of exact model matching with simultaneous disturbance rejection (EMMDR) for general neutral multi-delay systems, via proportional realizable controller feeding back measurable disturbances and measurement outputs, is studied. The desired model is assumed to be left-invertible. For this problem the following two major issues are resolved: the necessary and sufficient conditions for the problem to have a realizable solution and the general analytical expression of the controller matrices solving the problem. The results have been applied to control an internal combustion (IC) engine