Patent attributes
In a noncircular shape machining apparatus, a tool 7 is moved reciprocally in an X-axis direction by a tool-moving mechanism. A first acceleration sensor 6 is disposed on a saddle 11, which is an immovable section of the tool-moving mechanism. Further, a second acceleration sensor 15 is disposed on a spindle bearing 5 of a spindle that holds and causes a workpiece 1 to rotate. Additionally, displacements of the saddle 11 and the workpiece 1 are measured by these two acceleration sensors 6 and 15, and displacement in the relative distance between the workpiece 1 and the tool 7 is acquired as relative displacement on the basis of the two displacements that have been obtained. Additionally, the position of the tool 7 is calculated from the obtained displacement and the output value of an X-axis linear scale 12.
