SYNOPSIS

An improved predictive model of pneumatic jacks is introduced in order to develop a component oriented model library for the numerical prototyping of pneumatic actuators. First, the valve orifices model is derived from the ISO standard as a function of the orifice opening. Then the gas chamber behaviour is modelled using a rigorous theoretical development of conservation laws. Consequently, no assumption is required concerning the evolution of the gas only being considered as ideal. A fix parameter convective model is found acceptable to define the heat exchange between the gas and the jack environment. Finally, a representation model of the internal jack friction is proposed including the influence of pressure and working quadrant on viscous and Coulomb effects. The simulation structure is then presented and the model is validated using a step by step procedure.

KEY WORDS: pneumatic actuator, friction, pneumatic valve, gas chambers, dynamics.