Abstract
The main problem of using servohydraulic machines in fatigue testing comes from the fact that the actual load experienced by the specimen is always different than the load intended to fall on the specimen. In this paper, we present our experience in reducing the above discrepancy by using the intelligent-signal-generation principle. Specifically, we compare two different methods, i.e., the wait principle and the newly proposed inverse filtering method. Simulation results show that the wait principle is more accurate, but the low and unadjustable speed make this method impractical. On the other hand, although the inverse filtering speed is adjustable (with good level of accuracy), the command signal could be so large that it reaches the limiting capability of the hardware.