Patent ID: 6218764
Filing Date: 2001-04-17
Classification: H02N

Abstract:
An actuator, comprising:an electromechanical transducer for repeatedly producing linear displacement in a predetermined direction;a first member fixedly coupled to one end of said electromechanical transducer;a second member frictionally coupled to said first member, said first member and said second member being moveable in the predetermined direction; anda drive pulse generating means for supplying a drive pulse to said electromechanical transducer, wherein said drive pulse has the shape of a sawtooth waveform having a gradually changing portion and a rapidly changing portion, said drive pulse satisfying the following equations (a) and (b):0.4<(T1/T)<0.8 (a)0.35<(T2/T1)<0.95 (b)wherein T is a wavelength of the drive pulse;T1 is a pulse width of the drive pulse; andT2 is a width of the gradually changing portion of the drive pulse.