Methods for analyzing system operator coupling susceptibility are
described herein. In one embodiment, an open loop frequency response can
be compared to a related over-steer point. An over-steer point can be the
condition where, as operator gain is increased for an open loop system,
the corresponding closed loop gain at a corresponding resonance peak
increases by at least approximately the same amount as the increase in
operator gain or at least approximately a selected larger amount than the
increase in operator gain. In other embodiments, an open loop frequency
response can be compared to a critical gain rate. The critical gain rate
can be the rate of change of open loop gain per open loop phase angle of
the corresponding open loop system response at an over-steer point that
is associated with a zero decibel closed loop gain.