| 摘要 |
<p>A reversible positioning device contains a piezoelectric actuator (10) of a linear contact type urged against a rotary or a linear type movable element (20). The actuator is equipped with two sets of electrodes: (90), (110), (80) and (100), (120), (80) respectively. The control unit supplies electrical impulses to either one of the theses sets of electrodes to initiate periodic oscillations of the actuator (10) causing elastic compressions of the movable element (20) and subsequent movements in either one of the opposite directions. One particularly useful application is in the movable arm of the disk drive data storage system such as a CD-ROM or alike. Extreme accuracy of positioning of a readout head and a low inertia allow for fast response time approaching 2 msec. a novel control method is in supplying a higher voltage from a control unit for the longer forward motion of the positioning device followed by a shorter back movement due to lower voltage. That control method increases the positioning accuracy even further to as low as 0.2 microns.</p> |
