Patent ID: 7639232

Claim:
A method for braking an actuator comprising: generating a first actuator signal having a frequency approximately resonant to the actuator, the first actuator signal configured to drive the actuator; transmitting the first actuator signal to the actuator; generating a second actuator signal having approximately the frequency of the first actuator signal and a phase approximately 180 degrees out of phase to the first actuator signal, the second actuator signal configured to cause a braking force on the actuator; and transmitting the second actuator signal to the actuator, wherein generating the first actuator signal comprises: generating a first rectangular wave having a frequency approximately resonant to the actuator, generating a second rectangular wave having approximately the same frequency by logically exclusive-ORing the first rectangular wave with a digital signal in a first logic state; and generating the second actuator signal comprises: changing the digital signal to a second logic state, generating a third rectangular wave having approximately the frequency of the first actuator signal and a phase approximately 180 degrees out of phase to the first actuator signal by logically exclusive-ORing the first rectangular wave with the digital signal in a second logic state.