Abstract: This work presents an accurate model of a controlled pneumatic actuator. The work is concurrent with the development of a new control algorithm for this kind of systems, based on an accurate thermo-mechanical model and oriented to perform a complete trajectory control. The actuator is composed of a proportional servovalve and a cylinder with magnetical tracking. The cylinder is supported by a pair of linear bearings. The model proposed for the valve is based on a static experimental characterization. The model of the cylinder is obtained assuming that the thermodynamic processes in both chambers are isothermal and that the air is a perfect gas. Numerical simulations are compared with experimental recordings for step and sine input in open chain conditions.