Using a Conventional Servopneumatic System for Robust Motion Control in the Micrometer Range

Conventional pneumatic systems present several advantages over competitive technologies, as they do not exhibit significant heat or magnetic fields and present high force to volume ratios. Nevertheless, they are very difficult to control due to their inherent nonlinearities like friction forces or air compressibility. As a consequence, their use is limited to simple motion tasks. This paper uses a nonlinear control law, previously developed by the authors, to control a servopneumatic system in the micro meter range. Preliminary experimental results show that the control law leads to very accurate motion control in micro meter positioning tasks in any position of the piston stroke. The paper also shows, through experimental results, that the control law is robust to parametric variations (change of payloads) and to external constant disturbances (gravity force).