Observer based robust control of a linear motor actuated vacuum air bearing

A vacuum air bearing based linear drive is to be positioned with a relative accuracy in the nanometer range. This is achieved by use of the new control technique, observer based robust control (OBRC) originated by the second named author and its motion control application published here for the first time. It is shown that the amplitude of the vibration mode of the vacuum air bearing excited by motion of the air molecules in the vacuum air bearing can be reduced from ±20nm (using a cascaded controller) to ±10nm using OBRC. Comparisons are made between simulations and experiments.