| 摘要 |
PURPOSE: To make a drive circuit simple, by controlling a drive voltage in a way that an absolute value of a secondary differential term applied for an expansion and contraction time is larger than an absolute value of a critical secondary differential term that gives a boundary of dynamic and stationary frictional state between a drive plate and a moving body. CONSTITUTION: A drive voltage is controlled in away that an absolute value of a secondary differential term applied for an expansion time (t1 to t0 ) and a contraction time (t2 to t1 ) is made larger than an absolute value of a critical secondary differential term that gives a boundary of dynamic and stationary frictional state between a driving plate 12 and a moving body 15. When the piezoelectric elements 14a and 14b are shifted to the right during the expansion time, the drive plate 12 and the moving body 15 come in a dynamic frictional state, and the drive plate 12 is shifted just a distance of L5 relatively from the moving body 15, while the moving body 15 is not changed in position. When the piezoelectric elements 14a and 14b are shifted to the left, the drive plate 12 is shifted just a distance of L6 relatively from the moving body 15. |
