Dariusz Grzybek

LQG Control of the Smart Truss with the Piezoelectric Active Members

A truss is one of the most important parts of different structures applied in several areas of the contemporary industry. One of the most often appeared problems is the undesirable truss vibration activated, for example by the wind. The limitation of the undesired vibration is possible by the increase of the truss dimensions, but it leads to the increasing of the truss mass. The other way of the vibration damping is possible by the introduction of active elements, which generate the control forces acting on selected nodes of the truss. The piezoelectric actuators can be applicable elements to generate such control forces. Special active members are designed in order to introduce the piezoelectric actuators in the truss structure. A project of the control algorithm steering such members is a difficult task, because the truss with active members is MIMO control object. This article presents the results of the simulation research of LQG control system installed in exemplary truss with one, two or three piezoelectric active members. On the basis of the conducted simulation research one can claim that LQG control system could influence the increase of the vibration damping of such piezoelectric smart truss structure, without the increase of the truss mass.

Piezoelectric Generators in the Energy Harvesting Systems

Piezoelectric generator is a device used to convert mechanical energy into electrical energy. The basic element of the generator is made from piezoelectric material in which electrical energy is created as a result of deformations caused by reactions of mechanical structure of the generator. The amount of obtained electrical energy depends mainly on the piezoelectric material used, construction of the generator as well as a type of the source of mechanical energy. Construction of the generator is adjusted to the type of the source of mechanical energy. In order to obtain electrical energy from mechanical vibrations, the most frequent solution is beam structure. Effective electric energy generation by the piezoelectric generators depends on the following main factors: piezoelectric material used, generator structure, electronic system of the control and storage of energy, and the generator size. Generated by piezoelectric generators electric energy, can be used to power of miniaturized electronic devices with low power supply demand. The goal may be monitoring of the structure or industrial processes in hardly accessible places or/and in systems requiring the use of a big number of sensors. It will make cutting the operating costs possible and allow to create the eco-friendly technology without waste discharged batteries.