Normal-line detection method, normal-line detection device, and machine tool having normal line detection function

摘要

Provided is a normal-line detection method for finding the normal vector (Vn) of a measurement surface (21) of a measurement target (20) by measuring distances to the measurement target (20) by means of at least one distance detector (30) and calculating the normal vector (Vn) from the measurement results (L) thus obtained. In the method, the normal vector (Vn) of the measurement surface (21) is found by calculating the exterior product of a first vector (Vae) which connects a first measurement point (Qa) and a second measurement point (Qe) and a second vector (V'cg) which connects a third measurement point (Qc) and a fourth measurement point (Qg) and is shifted in parallel such that an end thereof is set at any one of the first measurement point (Qa) and the second measurement point (Qe). The first measurement point (Qa) is a point on the measurement target a distance to which is measured by the distance detector (30) from a first measurement position (Pa). The second measurement point (Qe) is a point on the measurement target a distance to which is measured by the distance detector (30) from a second measurement position (Pe) located opposite to the first measurement position (Pa). The third measurement point (Qc) is a point on the measurement target a distance to which is measured by the distance detector (30) from a third measurement position (Pc) located between the first measurement position (Pa) and the second measurement position (Pe). The fourth measurement point (Qg) is a point on the measurement target a distance to which is measured by the distance detector (30) from a fourth measurement position (Pg) located opposite to the third measurement position (Pc).