A comparative study between two control laws of an electropneumatic actuator

This paper focuses on a comparison between two positioning control laws of a half meter stroke electropneumatic disymmetrical cylinder controlled by two three-way servo-distributors : a fixed gains control law and a control law with scheduling gains. Using physical laws, the first part of this paper describes a nonlinear model of this process and focuses on the difficulty for obtaining servo-distributors mass flow rates. A specific choice of the control inputs leads to a single input model. A tangent linearised model is obtained. The two different control laws are described and implemented using a well-known dSPACE interface card. Experimental results obtained for point to point control are presented and discussed.