Synchronization strategy research of pneumatic servo system based on separate control of meter-in and meter-out

In the pneumatic synchronization system based on separate control of meter-in and meter-out, both motion trajectory and pressure trajectory could be tracked in a single pneumatic cylinder and then the cylinder could be controlled completely without internal dynamics. In this paper, an adaptive robust pressure controller is used to keep the pressure level in chamber of cylinder on an even keel when the pneumatic cylinder is moving, which will result in small variation of cylinder's friction force and facilitate the precise modeling of friction force, and an adaptive robust motion controller is designed to improve the motion tracking accuracy of pneumatic cylinder, and on-line parameter estimation of the flow coefficient is utilized to have improved model compensation, and moreover a synchronization controller is added to further reduce the synchronization error. Experimental results demonstrate that this synchronization strategy could not only make two cylinders synchronized moving accurately, but also obtain very smooth control inputs which indicate the effectiveness of model compensation.