Wyniki wyszukiwania - BazTech

1

SDRE applied to position and vibration control of a robot manipulator with a flexible link

Lima J. J., Tusset A. M., Janzen F. C., Piccirillo V., Nascimento C. B., Balthazar J. M., Brasil R. M. L. R. F.

Journal of Theoretical and Applied Mechanics

|

2016

|

Vol. 54 nr 4

1067--1078

EN

This paper presents position and vibration control of a flexible robot composed of two rigid and one flexible links. Position is controlled by the current applied to the DC motor armature. To control vibrations of the flexible structure, Shape Memory Alloys (SMA) are used. Due to phase transformations, the SMA can change its stiffness through temperature variation, considering and taking advantage of this characteristic the vibration control is done. Control is achieved via the State Dependent Ricatti Equations (SDRE) technique, which uses suboptimal control and system local stability search. The simulation results show the feasibility of the proposed control for the considered system.

2

A nonlinear electromechanical pendulum arm with a nonlinear energy sink control (NES) approach

Alişverişçi G. F., Bayıroluǧlu H., Felix J. L. P., Balthazar J. M., Brasil R. M. L. R. F.

Journal of Theoretical and Applied Mechanics

|

2016

|

Vol. 54 nr 3

975--986

EN

This paper considers the nonlinear dynamics of an electromechanical device with a pendulum arm and a Nonlinear Energy Sink (NES) put on the point of the pendulum suspension. It is shown that the (NES) is capable of absorbing energy from the system. The numerical results are shown in a bifurcation diagram, phase plane, Poincar´e map and Lyapunov exponents.

3

On suppression of chaotic motions of a portal frame structure under non-ideal loading using a magneto-rheological damper

Tusset A. M., Piccirillo V., Balthazar J. M., Brasil R. M. L. R. F.

Journal of Theoretical and Applied Mechanics

|

2015

|

Vol. 53 nr 3

653--664

EN

We consider chaotic motions of a portal frame structure under non-ideal loading. To suppress this chaotic behavior, a controlling scheme is implemented. The control strategy involves application of two control signals and nonlinear feedforward control to maintain a desired periodic orbit, and state feedback control to bring the system trajectory into the desired periodic orbit. Additionally, the control strategy includes an active magneto-rheological damper to actuate the system. The control force of the damper is a function of the voltage applied in the coil of the damper that is based on the force given by the controller.

4

Influence of ideal and non-ideal excitation sources on the dynamics of a nonlinear vibro-impact system

Moraes F. H., Pontes B. R. (jr), Silveira M., Balthazar J. M., Brasil R. M. L. R. F.

Journal of Theoretical and Applied Mechanics

|

2013

|

Vol. 51 nr 3

763--774

EN

The objective of the present work is to analyze the dynamics of a vibro-impact system consisting of two blocks of different mass coupled by a spring with two stages. Two different types of excitation sources for the system are used in the analysis: the first is an ideal excitation in form of a harmonic force, and the second is a non-ideal excitation in form of a DC electric motor with limited power supply which has an unbalanced rotor. The control parameter for both situations is the excitation frequency of the system. The analysis includes time histories of displacements and velocities, phase portraits and diagrams of the displacement and frequency, used to show the Sommerfeld effect. For certain values of the parameters of the system, the motion is chaotic. The mathematical model of the system is used to obtain an insight to the global dynamics of the vibro-impact system. The model with a non-ideal excitation is more realistic, complete and complex than the model with the ideal excitation.