Candidate: Felipe Barreto Campelo Cruz
Program: UFSC / POSMEC
Date: November, 2003
Advisor: Victor Juliano De Negri
Co-advisor: Raul Guenther
Cruz, F. B. C. Modelagem e controle não-lineares de um posicionador servopneumático industrial. 2003. Dissertação (Mestrado em Engenharia Mecânica). Universidade Federal de Santa Catarina, Florianópolis.
Abstract: The aim of this work is to optimize the performance of a servo-pneumatic positioning unit commanded by two electro-pneumatic pressure-regulator servo-valves, and to contribute to the development and improvement of controllers for pneumatic positioning systems that can enable the improvement of their dynamic performance and, consequently, allow the expansion of their application to tasks where the demands of velocity and accuracy are severe. The proposition is to adopt a control strategy that will allow the overcoming of the nonlinearities of the system associated to the air flow in the servo-valves, the keeping of the oscillations, due to the compressibility of the air, within limits, and the development of a way to solve the difficulties introduced by the friction between the contacting surfaces of the slider-piston system. Such a controller is a Proportional-Derivative (PD) with compensation of the effects of inertia and friction force, obtained through an estimate of both. Experimental implementation has confirmed the efficiency of the proposed control strategy for the overcoming of these difficulties. Detailed knowledge of the components, whether they be pneumatic or electric, has shown to be importante for the understanding of the problem. An IBM-PC computer equipped with a data acquisition board featuring a DSP (digital signal processor) was used for acquisition, control and signal processing.