LAUSR

Abstract This paper presents experimental parameter identification of a jet pipe electro-pneumatic servo actuator model, which represents a class of high performance fast actuation systems. Parameter identification is given including detailed representation of linear dynamics, hysteresis, and the mass flow rate characteristics of the jet pipe servo valve, besides the static friction model of the linear pneumatic cylinder. Model parameters are identified and the model formulation is validated through simulation and experimentation. The main contribution of this work is threefold. Firstly, the mass flow rate characteristics are identified using the pressure dynamic equation in one cylinder chamber without the use of a flow sensor. Secondly, a lag behaviour related to the non-modelled dynamics is found out by performing an experimental identification of the frequency response of the servo valve. Thirdly, a new experimental setup is presented to give the static friction model as a function of not only the relative velocity but also the pressures in the two cylinder chambers. The agreement between simulations and experimental data indicates that the Parameter identification methods presented are valid and constitute valuable tools, whether in the analysis and the design of actuation systems, or for use in model-based control. The modelling methodology used in this paper can be generalised to similar electro-pneumatic servo actuators.