The Parametric Identification Of A Stationary Process

In the problems of identification it is supposed that the process has at least one measurable input size and at least one measurable output size. The identification of a process has three stages: the obtaining of a registration of process measurable sizes; the choice of a proper mathematical model for the process; the extract of the parameter values of the mathematical models from registered data. The parametric identification problem is an optimization problem, in which the best combination of values for the model parameters set is searched. In the paper is presented the parametric identification of a water flow process in a laboratory stand. The identification had the following dims: detailed understanding of how the stand works, finding a new illustrative experiment for the stand, the application of advanced techniques of automat control, and the development of a project of new stand, meant to allow a large variety of experiments

On The Snubber Influence To The Switching And Conduction Losses In A Converter Using Switched Capacitor

The paper deals to design and to compute the snubber parameters influence on the switching and conduction losses of the transistors (IGBT) used as bidirectional switches in a converter with switched capacitor. The converter was modelled with difference equations, and the transistors during turn-on and turn-off processes were simulated by dynamically varying resistance models. The energy loss per switching, commutation time, the variation of the transistor voltage etc. and the influence of snubber parameters in each of these cases are shown in the context of a converter used as a 50Hz reactive power controller uni

Sliding mode control applied in trajectory-tracking of WMRs and autonomous vehicles

Tese de doutoramento apresentada à Fac. de Ciências e Tecnologia da Universidade de CoimbraThe thesis is structured as follows: • Chapter 2: Trajectory tracking problems are summarized. • Chapter 3: Kinematic and dynamic modeling of theWMRs and car-like robots are presented. • Chapter 4: The concept of sliding mode are first introduced. Then the fundamentals of SMC are summarized, including basic definitions, methods of sliding surface and control law design, robustness properties and the methods on handling chattering problems. New sliding-mode trajectory-tracking and slidingmode path-following controllers for WMRs and car-like vehicles, are also proposed in this chapter. • Chapter 5: The trajectory/path planning are developed, including the velocity profile. • Chapter 6: A model with two freedom degrees is considered for the HNC model. The user comfort is examined not only in the time domain, but also in the frequency domain. • Chapter 7: Experimental results obtained with the implementation of the proposed controllers in RobChair are summarized and discussed. • Chapter 8: Finally, conclusions are drawn and some suggestions for future work are provided

Sliding Mode Control for Trajectory Tracking of an Intelligent Wheelchair

This paper deal with a robust sliding-mode trajectory tracking controller, fornonholonomic wheeled mobile robots and its experimental evaluation by theimplementation in an intelligent wheelchair (RobChair). The proposed control structureis based on two nonlinear sliding surfaces ensuring the tracking of the three outputvariables, with respect to the nonholonomic constraint. The performances of theproposed controller for the trajectory planning problem with comfort constraint areverified through the real time acceleration provided by an inertial measurement unit

FUZZY MODELS AS DECISION-SUPPORT APPLICATIONS OF ELECTRICAL ENERGY TARIFFING

The paper is a decision – support application which design and use two fuzzy models to estimation an electrical energy tariff, as it to be sell at consumers. The fuzzy tariff estimation model integrate not only the S.C Electrica S.A. rate position, but and some constraints/ compulsions of National Authority of Settlements from Energy (NASE), beginning with 1999, in this transition period from Romania. The paper not refer to a price concrete case (internal tariff used in certain year, production price, transport price, distribution price, spot price, or an external price to be sold electrical energy – EE, etc). The paper shows how, by changing the parameters of S.C Electrica S.A and NASE, it is possible to can perform sensitivity tests on the tariff function model until we obtain an acceptable price. Much more: the two fuzzy models use different rules (conservative and aggressive, with hedge operators, respectively) for pricing. Finally, the paper not finished all fuzzy possibilities (rules) which can influences the expected value of a some EE tariff but, can create a discussion base about the way of approximate/ fuzzy reasoning, as a decision-support application to find a new EE price

Real Time Compensation of the Load Torque for DC Drive System

The objective of this paper is to improve the control quality of the DC drive system based on Arduino platform. The nameplate DC motor data are useful to provide the DC motor parameters. The cascade control loops provides good dynamic performances for the DC drive system. By using an adequate electric generator, the DC motor is loaded appropriately. Compared to the conventional control methods, in order to improve the load torque disturbances, this paper introduces feedforward load control loop. The simulation and experimental results are shown in this paper

Three fuzzy reasoning models as a decision suport aid, to find an electrical energy tariff

This contribution is a laboratory-work developed as an example of approximate (fuzzy) reasoning for students, possible to be used as a decision – support to estimate an electrical energy (EE) price for consumers. The three fuzzy tariff estimation models that are developed, integrate not only the S.C Electrica S.A.-single-supplier rate position, but and some (social) constraints/ compulsions of National Authority of Settlements from Energy (NASE) beginning with 1999, in this transition period from Romania. Although is possible, the paper not refer to a partial-price concrete case (internal tariff used in certain year, production price, transport price, distribution price, spot price, or an external price to be sold electrical energy, etc). This “laboratory-work-paper” shows how, by changing the parameters of S.C Electrica S.A. and NASE, it is possible to can perform sensitivity tests on the tariff function model, until can obtain an acceptable and true price. In this aim, the three fuzzy models use different rules for pricing: conservative, aggressive, and different order of words concerning the rules respectively, finally doing a comparation among prices and models. The paper not finished all fuzzy possibilities (rules) which can influences the expected value of a some EE tariff but, with certitude, can create a discussion base, about the way of approximate/ fuzzy reasoning, as a modality to find and to refine an EE price

On-line Identification of the DC motor Parameters by using Least Mean Square Recursive Method

The on-line least square parameters (electrical and mechanical) identification method of the separately DC motor is presented in this paper. The parameters of the DC machine are time dependent; therefore, for the DC drive control the on-line parameters identification procedure is mandatory. By knowing accurately the DC motor parameters, the parameters of the DC speed and current cascade controllers can be obtained