Reaction force cancellation without a balance mass

n many precision machines with an internal motion stage, the requirements for
throughput and accuracy pose conflicting demands on the system design. In this article, we show that active vibration isolation systems can be used to cancel the reaction forces of a motion stage placed on the payload while simultaneously isolating it from the floor. This cancellation is done in a feedforward manner, and system uncertainties and changes can be tracked by making the feedforward adaptive. The experimental validation shows that it is possible to almost completely remove the part of the payload acceleration that is correlated to the stage motion and the floor acceleration, over a wide frequency band.