IMPLEMENTATION OF THE LQG CONTROLLER FOR A WIND TURBINE TOWER-NACELLE MODEL WITH AN MR TUNED VIBRATION ABSORBER

Vibration of a wind turbine tower is related to fatigue wear, influencing reliability of the whole structure. The current paper deals with the problem of Linear-Quadratic-Gaussian (LQG) tower vibration control using specially designed and built simulation and laboratory tower-nacelle models with a horizontally aligned, magnetorheological (MR) damper based tuned vibration absorber located at the nacelle. Force excitation applied horizontally to the tower itself, or to the nacelle, is considered. The MR damper LQG control algorithm, including the Kalman state observer and LQR (Linear-Quadratic-Regulator) controller is analysed numerically and implemented on the laboratory ground, in comparison with the system with a deactivated absorber. Simulation and experimental results are presented

EVALUATION OF AN ENERGY HARVESTING MR DAMPER-BASED VIBRATION REDUCTION SYSTEM

The paper deals with an MR damper-based vibration reduction system with energy harvesting capability. The main part of the system creates an MR damper and a power generator based on an electromagnetic transduction mechanism, which are integrated into a stand--alone device (so called energy harvesting MR damper). The main objective of the work is to evaluate performance of the proposed vibration reduction system employed in a single DOF mechanical structure. The material outlines the design structure and characteristics of the energy harvesting MR damper, presents the vibration reduction system based on this damper and explores experimental testing of the system implemented in a single DOF mechanical structure. To demonstrate that the devised system is feasible, performance figures maps completed by experimental data are shown

Semi-active suspension system with an MR rotary damper Półaktywny system zawieszenia z rotacyjnym tłumikiem MR /

Tyt. z nagłówka.Bibliografia s. [64].Dostępny również w formie drukowanej.ABSTRACT: The paper is concerned with a laboratory semi-active suspension system (SAS), built to demonstrate and test a number of control algorithms. The heart of the system is the automotive engineering magnetorheological (MR) rotary damper used as an actuator. The MR rotary damper enables to control the SAS damping torque in a continuous way. A designed on-off controller automatically adjusts the damping coefficient to generate the torque required to reduce the amount of energy transmitted from the source of vibrations to the suspended equipment. The experimental results of laboratory investigations of the designed control algorithm in respect to the RD-2087-01 damper have been presented. STRESZCZENIE: W artykule przedstawiono laboratoryjny system półaktywnego zawieszenia pojazdu, przeznaczony do analizy i testowania algorytmów sterujących. Jako element wykonawczy zastosowano obrotowy tlumik magnetoreologiczny (MR). Tłumik ten umożliwia sterowanie w sposób ciągły momentem tłumienia poprzez zmianę wartości prądu w cewce. Zaproponowany w pracy regulator on-off dostosowuje współczynnik tłumienia do wytworzenia momentu tłumiącego, wymaganego do zredukowania energii mechanicznej przekazywanej ze źródła wibracji do chronionej układem zawieszenia masy. Przedstawiono wyniki badań eksperymentalnych na zbudowanym stanowisku laboratoryjnym, przeprowadzonych z wykorzystaniem zaprojektowanego regulatora dla użytego tłumika RD-2087-01. SŁOWA KLUCZOWE: tłumik magnetoreologiczny, system półaktywnego zawieszenia, algorytmy sterujące. KEYWORDS: fast prototyping, MR damper, semiactive suspension, control algorithms

MODELLING OF THE SEMI-ACTIVE SUSPENSION SYSTEM

The paper is concerned with a mathematical model of the Semi-Active Suspension system (SAS) of a vehicle equipped with the magnetorheological rotary brake manufactured by the Lord Corporation. SAS is a laboratory system animating the suspension action of a car quarter. A simulation model written in the MATLAB/Simulink environment is shown. The parameters of the mathematical model are identified by optimization procedures based on experimental data collected in the real-time. The mathematical model is verified. It means that appropriate system trajectories of SAS and the simulation model are compared

Ability of energy harvesting MR damper to act as a velocity sensor in vibration control systems

The study investigates the self-sensing ability in an energy harvesting magnetorheological damper (EHMRD). The device consists of a conventional linear MR damper and an electromagnetic harvester. The objective of the work is to demonstrate that the EHMRD with specific self-powered feature can also serve as a velocity sensor. Main components of the device and design structure are summarized and its operation principle is highlighted. The diagram of the experimental set-up incorporating the measurement and processing unit is provided, the experimental procedure is outlined and data processing is discussed. The self-sensing function is proposed whereby the relative velocity of the EHMRD can be reconstructed from the electromotive force (emf) induced in the harvester coil. To demonstrate the adequacy of the self-sensing action (i.e., the induced emf should agree well with the relative velocity), the proposed self-sensing function is implemented and tested in the embedded system that will be a target control platform. Finally, the test results of the system utilizing a switching control algorithm are provided to demonstrate the potentials of the EHMRD acting as a velocity sensor and to confirm its applicability in semi-active vibration control systems

Ability of Energy Harvesting Mr Damper to Act as a Velocity Sensor in Vibration Control Systems

The study investigates the self-sensing ability in an energy harvesting magnetorheological damper (EHMRD). The device consists of a conventional linear MR damper and an electromagnetic harvester. The objective of the work is to demonstrate that the EHMRD with specific self-powered feature can also serve as a velocity sensor. Main components of the device and design structure are summarized and its operation principle is highlighted. The diagram of the experimental set-up incorporating the measurement and processing unit is provided, the experimental procedure is outlined and data processing is discussed. The self-sensing function is proposed whereby the relative velocity of the EHMRD can be reconstructed from the electromotive force (emf) induced in the harvester coil. To demonstrate the adequacy of the self-sensing action (i.e., the induced emf should agree well with the relative velocity), the proposed self-sensing function is implemented and tested in the embedded system that will be a target control platform. Finally, the test results of the system utilizing a switching control algorithm are provided to demonstrate the potentials of the EHMRD acting as a velocity sensor and to confirm its applicability in semi-active vibration control systems

Fractional order, state space model of the temperature field in the pcb plate

In the paper the fractional order, state space model of a temperature field in a two-dimensional metallic surface is addressed. The proposed model is the two dimensional generalization of the one dimensional, fractional order, state space of model of the heat transfer process. It uses fractional derivatives along time and length. The proposed model assures better accuracy with lower order than models using integer order derivatives. Elementary properties of the proposed model are analysed. Theoretical results are experimentally verifed using data from industrial thermal camera

Implementacja podstawowego elementu ułamkowego na mikrokontrolerze

The paper presents the implementation of the basic fractional order element sγ, γ ∈ R on the STM32 microcontroller platform. The implementation employs the typical CFE and FOBD approximations, the accuracy of approximation as well as duration of calculations are experimentally tested. Microcontroller implementation of fractional order elements is known; however, real-time tests of such implementations have been not presented yet. Results of experiments show that both methods can be implemented at the considered platform. The FOBD approximation is more accurate, but the CFE one is faster. The presented experimental results prove that the STM32F7 family processor could be used to develop the embedded fractional-order control systems for a broad class of linear and nonlinear dynamic systems. This is crucial during the implementation of the fractional-order control in the hard real-time or embedded systems.W pracy przedstawiono implementację podstawowego układu ułamkowego rzędu sγ, γ ∈ R na platformie mikrokontrolera STM32. Implementacja wykorzystuje typowe aproksymacje CFE oraz FOBD. Dokładność aproksymacji oraz czas trwania obliczeń testowane są eksperymentalnie. Implementacja układów ułamkowych na mikrokontroler jest znana, jednak ich testy w czasie rzeczywistym nie były jak dotąd omawiane w literaturze. Wyniki wskazują, że obie metody można wdrożyć na rozważanej platformie. Aproksymacja FOBD jest dokładniejsza, z kolei CFE jest szybsza. Przedstawione rezultaty eksperymentów dowodzą, że procesor z rodziny STM32F7 może zostać wykorzystany do opracowania wbudowanych ułamkowych układów sterowania dla szerokiej klasy liniowych i nieliniowych układów dynamicznych. Zaprezentowane wyniki są istotne z punktu widzenia implementacji algorytmów ułamkowych w twardych systemach czasu rzeczywistego lub w systemach wbudowanych

The Frequency and Real-Time Properties of the Microcontroller Implementation of Fractional-Order PID Controller

The paper presents time, frequency, and real-time properties of a fractional-order PID controller (FOPID) implemented at a STM 32 platform. The implementation uses CFE approximation and discrete version of a Grünwald–Letnikov operator (FOBD). For these implementations, experimental step responses and Bode frequency responses were measured. Real-time properties of the approximations are also examined and analyzed. Results of tests show that the use of CFE approximation allows to better keep the soft real-time requirements with an accuracy level a bit worse than when using the FOBD. The presented results can be employed in construction-embedded fractional control systems implemented at platforms with limited resources