| 摘要 |
PROBLEM TO BE SOLVED: To provide a numerically controlled drive unit positively and quickly detecting an accidental collision even when a detection threshold is significantly low. SOLUTION: The drive unit 18a of a load has a motor 14a, and it is provided with the device for detecting an accidental collision, and first and second position sensors 15a and 16a respectively arranged in an upstream side and a downstream side of a transmission assembly 12a, and respectively providing first and second values of position. A calculation unit 20 enables calculation of an error signal d corresponding to a difference of the values of position. A distinguishing means is provided for analyzing consecutive error signals by using a spatial reference coordinate system (x<SB>R</SB>, d) as a function of a path intersected by the load. A filter having a rectangular or an exponential space window is particularly adapted to distinguish between an error due to an accidental collision, and an error due to other causes following normal work. Accordingly, particularly reliable and highly sensitive collision detection can be provided by an extremely low detection threshold. COPYRIGHT: (C)2006,JPO&NCIPI
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