Wyniki wyszukiwania - BazTech

1

Modal energy transfer by controlled structural connections

Ostrowski Mariusz, Błachowski Bartłomiej, Jankowski Łukasz, Pisarski Dominik

Diagnostyka

|

2020

|

Vol. 21, No. 1

61--70

EN

This paper describes a semi-active control strategy that allows to transfer the vibration energy from an arbitrarily induced to a selected structural mode. The intended aim of the proposed control strategy is energy harvesting from structural vibrations. Another potential application is related to structural safety. In the paper, a mathematical model is first introduced to describe the phenomenon of vibrational energy transfer, and then, based on this model, an efficient semi-active control strategy is proposed. Finally, some problems related to measurement techniques are discussed. The effectiveness of the proposed methodology is demonstrated in an example of energy transfer between vibrational modes of a three-bar planar frame structure.

PL

Niniejszy artykuł opisuje półaktywną strategię sterowania umożliwiającą transfer energii z dowolnej wzbudzonej postaci do innej wybranej postaci drgań własnych konstrukcji. Proponowana strategia sterowania może być wykorzystana w celu pozyskiwania energii z drgań konstrukcji. Inne potencjalne zastosowanie związane jest z kwestiami bezpieczeństwa konstrukcji. W artykule najpierw wprowadzony jest model matematyczny opisujący zjawisko transferu energii drgań, a następnie, w oparciu o ten model, przedstawiona jest efektywna strategia sterowania półaktywnego. Na koniec omówiono zagadnienia związane z technikami pomiarowymi. Skuteczność proponowanej metodologii pokazano na przykładzie transferu energii pomiędzy postaciami drgań płaskiej ramy portalowej.

2

Investigation of local and modal based active vibration control strategies on the example of an elastic system

Peukert Christoph, Pöhlmann Patrick, Merx Marcel, Müller Jens, Ihlenfeldt Steffen

Journal of Machine Engineering

|

2019

|

Vol. 19, No. 2

32--45

EN

Nowadays, feed axes are often equipped with multiple parallel-acting actuators in order to increase the dynamics of the machine tool. Also, additional actuators for active damping are widely used. Normally, the drives or actuators are controlled independently without consideration for the impact on each other. In contrast, by using the modal space control, the system can be decoupled and the modal control loops can be adjusted independently. This control approach is particularly suitable for motion systems, such as machine tools, which have more drives or actuators than degrees of freedom of movement. This paper deals with the pre-investigation of the modal-based vibration control for machine tools with additional actuators. The object of investigation is an elastic system with a movable saddle. The modal-based control is compared with a local control approach. The results obtained experimentally on the test rig are presented. The modal control is superior since, with the modal approach, each control loop corresponds to a specific vibration mode, and the control law for this loop is designed to provide the desired performance of the control system at the corresponding resonance frequency. The parameterisation of the control loops is simplified by modal control, since the modes can be controlled independently.

3

Linear adaptive structure for control of a nonlinear MIMO dynamic plant

Bańka S., Dworak P., Jaroszewski K.

International Journal of Applied Mathematics and Computer Science

|

2013

|

Vol. 23, no. 1

47--63

EN

In the paper an adaptive linear control system structure with modal controllers for a MIMO nonlinear dynamic process is presented and various methods for synthesis of those controllers are analyzed. The problems under study are exemplified by the synthesis of a position and yaw angle control system for a drillship described by a 3DOF nonlinear mathematical model of low-frequency motions made by the drillship over the drilling point. In the proposed control system, use is made of a set of (stable) linear modal controllers that create a linear adaptive controller with variable parameters tuned appropriately to operation conditions chosen on the basis of two measured auxiliary signals. These are the ship’s current forward speed measured in reference to the water and the systematically calculated difference between the course angle and the sea current (yaw angle). The system synthesis is carried out by means of four different methods for system pole placement after having linearized the model of low-frequency motions made by the vessel at its nominal “operating points” in steady states that are dependent on the specified yaw angle and the sea current velocity. The final part of the paper includes simulation results of system operation with an adaptive controller of (stepwise) varying parameters along with conclusions and final remarks.

4

Application of modal control for automobile cruise control

Zbrutsky A. V., Kaveshgar M.

Archive of Mechanical Engineering

|

2011

|

Vol. LVIII, nr 1

115-126

EN

A complete system of a Laser Radar is described in this paper. One explains the principles of the laser and all additional devices used in this system in order to obtain a compact and eye-safe system. The principle and realization of algorithms for controlling the cruise and speed of the vehicle are described. By applying modal control, and choosing the optimal mode for reducing the speed, one derives the system equation and determines its coefficients. Finally, the paper presents simulations of the laser scanning system, the modal control system and the behavior of the system affected by different errors and disturbances. The effects of instrumental errors are defined and simulation is performed illustrating how such a control system is influenced by internal and external disturbances.

PL

W artykule opisano kompletny system radaru laserowego. Wyjaśniono zasady działania lasera i wszystkich dodatkowych elementów zastosowanych po to, by uzyskać system o małych rozmiarach i bezpieczny dla wzroku. Opisano zasadę i realizację algorytmów sterowania przebiegiem i prędkością pojazdu. Stosując sterowanie modalne i wybierając optymalny sposób redukcji prędkości wyprowadzono układ równań i wyznaczono ich współczynniki. W końcowej części zaprezentowano symulację laserowego systemu skanowania, systemu sterowania modalnego i działania systemu w obecności błędów i zakłóceń. Zdefiniowano skutki błędów aparaturowych i przeprowadzono symulację ilustrującą wpływ wewnętrznych i zewnętrznych zakłóceń na działanie takiego systemu.

5

O sterowaniu nieliniowymi obiektami dynamicznymi MIMO w przełączalnej strukturze liniowych regulatorów modalnych

Bańka S., Dworak P., Brasel M.

Pomiary Automatyka Kontrola

|

2010

|

R. 56, nr 5

385-391

PL

W artykule przedstawia się wieloregulatorową, przełączalną strukturę układu sterowania nieliniowymi obiektami dynamicznymi MIMO na przykładzie sterowania położeniem statku wiertniczego z wykorzystaniem nieliniowego modelu wolnozmiennych ruchów statku nad punktem wiercenia w trzech stopniach swobody ruchu (3DOF). W proponowanej strukturze układu wykorzystuje się zestaw liniowych regulatorów modalnych współpracujących z dodatkowym układem sterowania w pętli otwartej, odsprzęgniętym statycznie lub dynamicznie. Syntezy układu dokonuje się poprzez linearyzację przyjętego opisu obiektu sterowania w nominalnych "punktach pracy", zależnych od zadawanego kąta kursowego statku i wartości prądu morskiego. Prezentowane wyniki badań dotyczą trzech odmian przełączalnej struktury układu: (i) klasycznej, z regulatorami modalnymi przełączanymi w momencie zmiany wartości sygnałów odniesienia gdy powodują one zmianę "punktu pracy" układu oraz nieklasycznej, w której regulatory modalne są przełączane dopiero po zadziałaniu pomocniczego układu sterowania, odsprzęgniętego (ii) statycznie lub (iii) dynamicznie. Działanie zaproponowanych odmian układów sterowania zilustrowano przykładami symulacji z nieliniowym modelem ruchów statku wiertniczego WIMPEY SEALAB w środowisku MATLAB/Simulink.

EN

In the paper a multicontroller-based switchable control system structure is proposed to control nonlinear MIMO plants. The considered structure contains a set of linear feedback controllers operating together with an additional, decoupled loop of the control system. The nonlinear model of low-frequency (LF) motions of a drilling vessel in three degrees of freedom (3DOF) on the sea surface is used as a MIMO plant to be controlled. The system synthesis is carried out by linearisation of the adopted nonlinear plant model at its nominal "working points" that depend on the preset ship yaw angle and the see current velocity. The investigation results presented concern three types of switched structures: (i) the classic one with a set of (stable) modal controllers switched at the moment of changing the reference signals with subsequent changes of the system "working point", and the non-classic structure in which modal controllers are switched after running an auxiliary decoupled control loop either statically (ii) or dynamically (iii). Performance of the proposed control systems is illustrated by examples of simulation results carried out in MATLAB/Simulink using the nonlinear model of motions of the WIMPEY SEALAB drilling vessel.

6

Control system of beam vibration using piezo elements

Gosiewski Z., Sochacki A.

Archives of Control Sciences

|

2003

|

Vol. 13, no. 3

375-385

EN

In modern mechanical contructions active damping seems to be essential. But real mechanical contructions are complicated in shape and are composed of components with distributed parameters. That is why advanced modeling techniques should be implemented in the process of designing of vibration control system. In this paper we design a vibration control system for cantilever beam. As a sensor of the beam movement and as an actuator we use piezoelectric elements coupled with hardware of dSpace and software of Matlab-Simulink. The relations describing influence of piezo-actuator on the beam bending has been found. Measurement equation for piezo sensor was also prepared. Control system was designed for a few controlled modes. The influence of control system on non-controlled modes is considered.

7

Modal control approach to the test maneuver design for aircraft flight tests

Brusov V., Ovcharenko V.

Research Bulletin / Warsaw University of Technology, Institute of Aeronautics and Applied Mechanics

|

2001

|

nr 11

25-28

EN

A problem of test maneuver design is discussed in the case of statically unstable aircraft. The results obtained can be applied to formulation of the control laws for an aircraft within a predetermined frequency range. There appears a kind of duality for such control laws, namely, an input signal stabilizes and disturbs the dynamic system states at the same time.

8

Control of plate vibrations using smart technology

Chantalakhana C., Stanway R.

Applied Mechanics and Engineering

|

2000

|

Vol. 5, no 1

251-267

EN

In this paper, the authors describe progress on the development of a hybrid (active/passive) scheme for use in adaptive structures. An aluminium plate is employed as the demonstrator. The technique is based upon the use of a finite element model of the plate, extended to include passive control in the form of viscoelastic and constraining layers. Experimental results are presented to demonstrate the validity of the finite element model of the plate. Onto this framework is superimposed an active control scheme, formulated in modal state space. Emphasis is placed upon model reduction to obtain a low-order controller and to minimise the spillover effects which are induced when such controllers are implemented. Through a series of numerical experiments, it is shown how the presence of passive control introduces damping to improve robustness of modal control strategies. The paper concludes with a discussion of issues which remain to be resolved.