A New Approach to Model a Pneumatic Positioning System

Abstract

Pneumatic positioning systems are relatively light, clean andoflow costpresenting a good relationship between weight and power. These features make this kind of system a good choice of actuating for most applications. It appears, however, that the nonlinearities inherent to these systems are factors that complicate there application, turning them into subject of research for different authors. In this context, it is observed that there is a point less explored then other ones, related to the mathematical modeling of the dynamics of the adopted control valve. Several authors neglect this dynamic behavior by considering it is very high compared to the rest of the systems dynamics. Related to this claim, it is intended, in this paper, to develop a mathematical model representative of a pneumatic positioning system including the dynamic behavior of a proportional directional control valve to establish its real relevance in the global model of the pneumatic positioning system. The theoretical analysis that allows the formulation of the mathematical model is based on the concepts of fluid mechanics and on the laws of conservation of mass and energy. The results for the validation of the model are obtained by computer simulation, which are then compared to experimental results.