Mikulas Huba

Performance Portrait Method: a new CAD Tool

A revised view on teaching basic process control for bachelor and master students is presented. Practical topics are emphasized at the expense of a number of traditional theoretical topics. New teaching material in the form of interactive simulators, instructional videos, and a number of identical portable laboratory rigs have increased the pedagocical quality. The main results are an increase of the practical applicability of the course and more content students and instructors.Abstract The Performance Portrait Method opens new possibilities for analysis and design of the optimal and robust control. In different settings and in a simple and graspable way it allows to visualize influence of chosen control parameters on the loop performance, no matter how a peculiar dynamics is considered (with a long dead time, parameter uncertainties, constraints, etc.). Its use in design of the PI control for a single integrator + dead time is considered.

Constrained Pole Assignment Control

This chapter gives an overview of simple controllers for SISO systems based on the generalization of the linear pole assignment method for constrained systems with dynamics ranging from relay minimum time systems to linear pole assignment systems. The design is based on splitting the nth-order system dynamics into n first-order ones, which can be constrained without any problems with stability and overshooting. It requires a successive decrease of the distance of the representative point from the next invariant set with lower dimension. Since the distance of the representative point to such invariant set can be defined in many ways, the construction of the constrained controllers is not unique. The controllers derived from the second-order integrator are simple, appropriate also for extremely fast application, and easy to tune by a procedure that generalizes the well-known methods by Ziegler and Nichols, or ?Astrom and Hagglund, respectively.

New Thermo-Optical Plants for Laboratory Experiments

Abstract This paper explains motivation and gives a brief development history of a laboratory model of thermo-optical plant. Then it continues with a short description of linear and nonlinear identification and control experiments that may be carried out with the recently innovated model directly in a classroom from the Matlab/Simulink environment, or remotely via Internet.

Noise attenuation motivated controller design. Part II: Position control

This paper treats a noise attenuation motivated position controller design outlined in [1]. This modular approach to a filtered PD and a disturbance observer based filtered PID (FPD and DO-FPID) control design, including an experimental evaluation of an optimal filter degree choice, is extended to a constrained control grounded in the invariant set approach [2]-[4]. Loop performance is evaluated by recently introduced measures for deviations from monotonic and two-pulse shapes of transients typical for control of plants with dominant 2nd order dynamics. The analysis shows that a simplified disturbance observer (DO) based constrained filtered PID controller (DO-CFPID) derived for a double integrator plant model gives an interesting performance also for constrained integral systems with a stable mode. It remains simple and it offers an excellent performance also from the point of view of the noise attenuation versus speed of transients.

Experimental evaluation of a DO-FPID controller with different filtering properties

Abstract The paper brings experimental results and evaluation to modular disturbance observer based filtered PD and PID controller design based on theoretical results of papers Huba (2013b,c). The approach is focused on achieving the possibly best filtering properties by keeping nearly constant dynamics of the setpoint responses. The developed controller applied to a positional DC motor control is evaluated for different values of the tuning parameter T D and different filter orders n by using time and shape related performance measures.

Symbolic Computation for Nonlinear Systems Using Quotients over Skew Polynomial Ring

Nonlinear control systems are more difficult to handle than linear, since the associativity is not valid. Laplace transforms and transfer functions, which form a symbolic computation for linear systems, are, therefore, disabled. A modern development of nonlinear control systems is thus related mainly to the systematic use of differential algebraic methods. However, such methods allow us to introduce similar symbolic computation also for nonlinear systems. To provide a basis for such a symbolic computation the theory of non-commutative polynomials over the field of meromorphic functions is introduced. In that respect, differential operators, which act on one-forms, play a key role. They form the left skew polynomial ring. Quotients of such polynomials stand for transfer functions of nonlinear systems. In other words, presented paper tries to show that there is no reason to believe well known dogma saying that nonlinear systems have no transfer functions

Open flexible P-controller design

The paper represents first part of two contributions dealing with simplified modular design of constrained P and disturbance observer (DO) based PI control with different filtering properties illustrated by example of speed servo control. This first part is devoted to analysis of the core structure of the P controller tuned for different types of nonmodelled or filter dynamics. Openness of the approach means that for approximating additional dynamics of the P-controller structure different filters may be used without necessity to repeat in the nominal case analysis of the optimal and critical tuning. By simpler means, flexible approach enabling to fit requirements of particular loop and simultaneously offering reasonably better performance than the traditional controller design based on Luenberger disturbance observer for reconstruction of the velocity signal is proposed. Achieved performance is evaluated by newly introduced measures for deviations from monotonic and one-pulse shapes of transients typical for control of plants with dominant 1st order dynamics.

Modular PID-controller design with different filtering properties

The paper presents second part of two contributions dealing with simplified modular design of filtered PD and disturbance observer (DO) based filtered PID control (DO-FPID) illustrated by example of positional servo control. This second part is devoted to the analysis of DO-FPID controller tuned for different types of nonmodelled or filter dynamics. By employing nth-order filters, openness of the new approach allows to keep nearly fixed dynamics of the transients and to change noise attenuation without necessity to repeat in the nominal case analysis of the optimal and critical tuning. Thereby, the number of tuning parameters remains minimal. Achieved performance is evaluated by newly introduced measures for deviations from monotonic, one- and two-pulse shapes of transients typical for control of plants with the dominant 2nd order dynamics.

Experiments in Control Education

Abstract This paper reports about experience in building Control Laboratory and in organising the learning process with the aim to foster an active and creative learning by doing.

Open flexible PD-controller design for different filtering properties

The paper represents first part of two contributions dealing with simplified modular design of filtered PD (FPD) and disturbance observer (DO) based filtered PID control (FPID) illustrated by example of positional servo control. This first part is devoted to analysis of the FPD controller tuned for different types of nonmodelled or filter dynamics. Openness of the approach means that different order filters required for implementation of these controllers and noise attenuation may be introduced without necessity to repeat in the nominal case analysis of the optimal and critical tuning. By simpler means, flexible approach enabling to fit filtering requirements of particular loop is proposed. Achieved performance is evaluated by newly introduced measures for deviations from monotonic and two-pulse shapes of transients typical for control of plants with dominant 2nd order dynamics.