  In this paper, a frequency separation based adaptive feedforward control
algorithm is developed with the ability to identify the plant and do
compensation region by region. In this algorithm, the accelerometer signal is
filtered by a series of uniformly distributed bandpass filters to generate a
bunch of subband signals which are mutually exclusive in spectrum. In each
subband, the corresponding subband signal acts as the feedforward signal and
only the frequency response of system in that region needs to be identified,
thus a pretty low order model can be expected to have efficient compensation.
Starting from the first region, the feedforward control parameters are learned
simultaneously with the low order plant model in the same region and then moves
to the next region until all the regions are performed.
