Patent ID: 8384316

Claim:
A vibration device adapted to produce haptic sensations, comprising: a base member; a plurality of actuators being coupled to the base member and including: a first actuator having a first member and a second member, the first member thereof being operatively coupled to the base member, and the second member thereof being moveable relative to the first member of the first actuator, and a second actuator having a first member and a second member, the first member thereof being operatively coupled to the base member, and the second member thereof being moveable relative to the first member of the second actuator; and means for modified synchronization of vibration of at least the first and second ones of the plurality of actuators, wherein the second actuator vibrates at a frequency that is an integer multiple of the vibration frequency of the first actuator, the value of the integer being greater than one; wherein vibrations from the first and second actuators are superimposed to produce a combined force vector F combined according to the following equation: F combined =a 1 A 1 +a 2 A 2 , where a 1 and a 2 are unit vectors aligned with corresponding directions of the first actuator and the second actuator, respectively; wherein the combined force vector F combined is controlled by modifying amplitudes of vibration of the first and second actuators when repeated superposition of peak amplitudes occur.