| 摘要 |
First, second and third sensors 11, 12 and 13 emit electromagnetic waves, receive electromagnetic waves emitted by the first, second and third sensors 11, 12 and 13 and reflected by an object 9 or electromagnetic wave emitted by the object 9 that received the electromagnetic waves emitted by the first, second and third sensors 11, 12 and 13, and specify distances between themselves and the object 9, respectively, based on time differences between emissions and receptions of the electromagnetic waves, and a control section 3 specifies three-dimensional coordinates of the object 9 based on the distances between the respective sensors 11, 12 and 13 and the object 9, determines whether or not the three-dimensional coordinate of the object 9 falls within a predetermined region and stops a motor when the three-dimensional coordinates of the object 9 falls within the region. |
