Control method of profile measuring apparatus

At least one tangible, non-transitory computer-readable medium storing an executable set of instructions for controlling a profile measuring apparatus that includes a probe having a stylus head at a distal end and a displacement mechanism displacing the probe, the profile measuring apparatus detecting contact between the stylus head and a surface of a work piece, and measuring a profile of the work piece, wherein the set of instructions, when executed by a computer processor, cause the computer processor to execute operations comprising:

• finding a scanning path along which the stylus head is displaced based on design data of the work piece;
• while controlling a depression amount of the probe toward the work piece to maintain a standard depression amount, displacing the stylus head along the scanning path;
• generating, via a motion controller of the profile measuring apparatus, a probe displacement instruction according to a composite speed vector V represented by the following equation:
• composite speed vector V=Gf·Vf+Ge·Ve+sg(p)·Gc·Vc2
• wherein:
• a path speed vector Vf is a vector along which the probe is displaced along the scanning path,
• a depression correction vector Ve is a vector maintaining the depression amount of the probe toward the work piece at the standard depression amount,
• a second course correction vector Vc2 is represented by (Vc1·q)q,
• a first course correction vector Vc1 is a vector in a direction correcting a probe position such that the stylus head is oriented along a scanning course,
• a course correction direction vector q is a vector given by a vector product of the normal line of the surface of the work piece and the path speed vector Vf,
• when the normal direction of a measured surface, which is calculated based on the design data of the work piece, is defined as a nominal normal direction vector Nw, p is a scalar product of the second course correction vector Vc2 and the nominal normal direction vector Nw, and a mathematical sign determination function sg(p) is a function returning +1 or −1 in accordance with a value of p, and
• Gf, Ge, and Gc are each a predetermined coefficient;
• and
• displacing the probe in accordance with the generated probe displacement instruction.