  Gear box dynamics is characterised by a periodically changing stiffness and a
backlash which can lead to a loss of the contact between the teeth. Due to
backlash, the gear system has piecewise linear stiffness characteristics and,
in consequence, can vibrate regularly or chaoticaly depending on the system
parameters and the initial conditions. We examine the possibility of a
nonfeedback system control by introducing a weak resonant excitation term and
through adding an additional degree of freedom to account for shaft flexibility
on one side of the gearbox. We shall show that by correctly choosing the
coupling values the system vibrations may be controlled.
