| 摘要 |
PURPOSE:To enhance feed accuracy of a table, by continually counting a deviation value of the moving instruction value to a feed thread from an actual moving value of the table and finely moving a nut, engaged with the feed thread, or the table through a piezoelectric element or the like so as to correct the counted value. CONSTITUTION:A table driving device, if an instruction pulse is output from a control instruction circuit 10 for moving a table 1 in a direction F, rotates a feed thread 5 by a motor 8. Here the table 1, when a clearance is provided in a junction surface between the thread 5 and a nut 6 engaged with the thread 5, is not moved even if the thread 5 rotates. Consequently, a deviation counter 11, adding only the instruction pulse from the circuit 10, increases an output. As a result, the device, controlling one piezoelectric element 7a in a extending direction simultaneously the other piezoelectric element 7b in a contracting direction through a D/A converter circuit 12 and a voltage divider circuit 13, corrects the clearance with the thread 5 by finely moving the nut 6 in the direction F. |
