Apple Inc.
Dampening mechanical modes of a haptic actuator using a delay

Abstract:

Described herein is a method for determining a higher order resonance mode frequency of a haptic actuator for an electronic device. The higher order resonance mode frequency may correspond to a frequency in which a mass of the haptic actuator exhibits undesired movement. The movement may cause the mass to collide or otherwise impact an enclosure of the haptic actuator. Once the higher order resonance mode frequency is determined, a delay or a polarity inversion may be added to one or more of a series of input waveforms to suppress or brake the undesired movement.