Method and apparatus for controlling vibrotactile sensations for haptic
feedback devices. An actuator in a haptic feedback device includes a
rotatable eccentric mass, and information is received at the haptic
feedback device causing a drive signal. The drive signal controls the
actuator to oscillate the mass in two directions about an axis of
rotation of the actuator such that the oscillation of the mass induces a
vibration in the haptic feedback device. The magnitude and frequency of
the vibration can be independently controlled by adjusting a magnitude
and a frequency, respectively, of the drive signal. The vibrations can
also be provided in a bi-directional mode or uni-directional mode to
provide the most efficient magnitude of the vibrotactile sensations. The
haptic feedback device can be, for example, a gamepad controller
receiving commands from a host computer providing a graphical
environment.