The design and implementation of an accelerometer-assisted velocity observer

This paper presents a dynamically compensated velocity observer (DCVO), in which acceleration measurement is employed to estimate velocity. Its sensitivity to the noise that is associated with the acceleration measurement is formulated and compared with that of a conventional state-space velocity observer (SSVO). Unlike the SSVO, the DCVO is completely insensitive to an accelerometer offset. The DCVO, the SSVO and a common ITM-based estimator are all realized in a linear motion stage, to determine their effectiveness. A sliding-mode controller is also implemented with different velocity observers, and it is shown that the DCVO enables high-frequency switching of the sliding-mode controller and also practically improves the positioning accuracy.