Design and control of a hydraulic press

The present paper describes the development of a 100kN hydraulic actuated press to perform aluminum stamping operations as well as mechanical tests. The press has two hydraulic servomechanisms: a hydraulic cylinder, driven by a servo-solenoid flow control valve, to support the punch tool; a hydraulic cylinder, where the chamber pressure is controlled by a servo-solenoid pressure control valve, to support the operations of loading and unloading of the press blank holder. A real time DSP based control card form dSPACE, which is directly programmed by the Matlab/Simulink environment, is used to implement the control and monitoring tasks and to perform data acquisition. The cylinders piston positions and chambers pressures are acquired with two optical scales and with analogue pressure sensors, respectively. The software setup allows the implementation of a hybrid controller (force + position) for the punch in such a way that it will be easy to switch between position and/or force control. A computer vision system is also integrated with the press control system in order to measure experimental data based on video images. An experiment to automatically measure the springback angle on an aluminum stamping operation is used, as an example, to show the functionality of the overall control and instrumentation systems.